WorldWideScience

Sample records for microporous pilcs synthesis

  1. Fluoride-assisted synthesis of bimodal microporous SSZ-13 zeolite

    NARCIS (Netherlands)

    Zhu, Xiaochun; Kosinov, Nikolay; Hofmann, Jan P.; Mezari, Brahim; Qian, Qingyun; Rohling, Roderigh; Weckhuysen, Bert M.; Ruiz-Martinez, Javier; Hensen, Emiel J. M.

    2016-01-01

    The presence of small amount of fluoride in alkaline hydrothermal synthesis of SSZ-13 zeolite yields bimodal microporous particles with substantially improved performance in the methanol-to-olefins (MTO) reaction. Hydrocarbon uptake measurements and fluorescence microspectroscopy of spent catalysts

  2. Fluoride-assisted synthesis of bimodal microporous SSZ-13 zeolite.

    Science.gov (United States)

    Zhu, Xiaochun; Kosinov, Nikolay; Hofmann, Jan P; Mezari, Brahim; Qian, Qingyun; Rohling, Roderigh; Weckhuysen, Bert M; Ruiz-Martínez, Javier; Hensen, Emiel J M

    2016-02-21

    The presence of small amount of fluoride in alkaline hydrothermal synthesis of SSZ-13 zeolite yields bimodal microporous particles with substantially improved performance in the methanol-to-olefins (MTO) reaction. Hydrocarbon uptake measurements and fluorescence microspectroscopy of spent catalysts demonstrate enhanced diffusion through micropores at the grain boundaries of nanocrystals running through the zeolite particles. Fluoride-assisted SSZ-13 synthesis is a cheap and scalable approach to optimize the performance of MTO zeolite catalysts.

  3. Conjugated microporous polymers: design, synthesis and application.

    Science.gov (United States)

    Xu, Yanhong; Jin, Shangbin; Xu, Hong; Nagai, Atsushi; Jiang, Donglin

    2013-10-21

    Conjugated microporous polymers (CMPs) are a class of organic porous polymers that combine π-conjugated skeletons with permanent nanopores, in sharp contrast to other porous materials that are not π-conjugated and with conventional conjugated polymers that are nonporous. As an emerging material platform, CMPs offer a high flexibility for the molecular design of conjugated skeletons and nanopores. Various chemical reactions, building blocks and synthetic methods have been developed and a broad variety of CMPs with different structures and specific properties have been synthesized, driving the rapid growth of the field. CMPs are unique in that they allow the complementary utilization of π-conjugated skeletons and nanopores for functional exploration; they have shown great potential for challenging energy and environmental issues, as exemplified by their excellent performance in gas adsorption, heterogeneous catalysis, light emitting, light harvesting and electrical energy storage. This review describes the molecular design principles of CMPs, advancements in synthetic and structural studies and the frontiers of functional exploration and potential applications.

  4. HYDROTHERMAL SYNTHESIS OF NANO-METER MICROPOROUS ZINC FERRITE

    Institute of Scientific and Technical Information of China (English)

    Xiaoling Hu; Ping Guan; Xin Yan

    2004-01-01

    Nano-meter microporous zinc ferrite was prepared by a hydrothermal method, using triethylamine as a template. Adsorption curves showed that the product had a microporous structure. The effects of precursor pH, reaction temperature and reaction time on the preparation were studied, yielding optimal conditions: pH=11,448 K, 360 min. The morphology of zinc ferrite as observed by TEM, showed that zinc ferrite was well-crystallized and well-dispersed with little conglomeration.

  5. Electrochemical Synthesis of a Microporous Conductive Polymer Based on a Metal-Organic Framework Thin Film

    KAUST Repository

    Lu, Chunjing

    2014-05-22

    A new approach to preparing 3D microporous conductive polymer has been demonstrated in the electrochemical synthesis of a porous polyaniline network with the utilization of a MOF thin film supported on a conducting substrate. The prepared porous polyaniline with well-defined uniform micropores of 0.84 nm exhibits a high BET surface area of 986 m2 g−1 and a high electric conductivity of 0.125 S cm−1 when doped with I2, which is superior to existing porous conducting materials of porous MOFs, CMPs, and COFs.

  6. Functionalized polymer networks: synthesis of microporous polymers by frontal polymerization

    Indian Academy of Sciences (India)

    N S Pujari; A R Vishwakarma; T S Pathak; A M Kotha; S Ponrathnam

    2004-12-01

    A series of glycidyl methacrylate (GMA)–ethylene dimethacrylate (EGDM) copolymers of varying compositions were synthesized by free-radically triggered thermal frontal polymerization (FP) as well as by suspension polymerization (SP) using azobisisobutyronitrile [AIBN] as initiator. The two sets of copolymers were characterized by IR spectroscopy and mercury intrusion porosimetry, for determination of epoxy number and specific surface area. Frontal polymerization was more efficient, yielding greater conversions at much shorter reaction times. The self-propagating frontal polymerization also generates microporous material with narrow pore size distribution. It yields higher internal pore volume and surface area than suspension polymerization, surface morphologies are, however, inferior.

  7. Synthesis of Microporous Materials and Their VSC Adsorption Properties

    Science.gov (United States)

    Yokogawa, Y.; Morikawa, H.; Sakanishi, M.; Utaka, H.; Nakamura, A.; Kishida, I.

    2011-10-01

    Oral malodor is caused by volatile sulfur compounds (VSC) such as hydrogen sulfide (H2S), methyl mercaptan and dimethyl sulfide produced in mouth. VSC induces permeability of mucous membrane and oral malodor formation. Thus, the adsorbent which highly adsorbs VSC should be useful for health in mouth and may prevent teeth from decaying. The microporous material, hydrotalcite, was synthesized by a wet method, and the H2S adsorption was studied. The samples, identified by powder X-ray diffraction method, were put into glass flask filled with H2S gas. The initial concentration of H2S was 30 ppm. The change in concentrations of H2S was measured at rt, and the amount of H2S absorbed on the hydrotalcite for 24 h was 300 micro L/g. The samples were taken out from the above glass flask and put into a pyrolysis plant attached to gas chromatography-mass spectrometry to determine the amount of H2S desorbed from samples. Only 3 % of H2S was desorbed when heated at 500 °C. H2S in water was also found to adsorb into hydrotalcite, which was confirmed by the headspace gas chromatography with flame photometric detector. The hydrotalcite material should be expected to be an adsorbent material, useful for health in mouth.

  8. Adsorption of Phenol and Its Chlorine Derivatives on PILCS and Organo-PILCS

    Science.gov (United States)

    Tahani, A.; Karroua, M.; El Farissi, M.; Levitz, P.; van Damme, H.; Bergaya, F.; Margulies, L.

    1999-03-01

    Modification of smectite by highly charged inorganic polycations gives a type of materials called Pillared Clays (PILCS). These materials are also potential candidates for sorbents of compounds of agricultural interest , or of pollutants molecules in wastewater treatment. Modified PILCS by the cationic surfactant (BTDDMAC) or by its polar head, the benzyl trimethyl ammonium chloride (BTMAC), are used as sorbent supports for phenol and its chlorine derivatives, as pollutants molecules. The adsorption results of these organic molecules are compared to there adsorption on non treated PILCS. Generally, the organophilic nature of PILCS increases the adsorption of chlorophenols. The adsorption properties of phenol are considerably improved on BTMAC treated PILCS. La modification des smectites par les polycations inorganiques très fortement chargés donne des matériaux appelés argiles à piliers (PILCS). Ces matériaux sont potentiellement intéressants comme supports d'adsorption pour des molécules d'intérêt agronomique ou pour des molécules polluantes dans le cas du traitement des eaux usées. Les PILCS modifiés par un tensioactif cationique (BTDDMAC) ou par sa tête polaire, le chlorure de benzyl trimethyl ammonium (BTMAC) ont été utilisés comme supports d'adsorption du phénol et de ses dérivés chlorés. Les résultats d'adsorption de ces petites molécules organiques ont été comparés à leur adsorption sur des argiles à piliers non traitées (non organophiles). Globalement, la nature organophile des organo-PILCS accroit l'adsorption des chlorophénols. Les propriétés d'adsorption du phénol sont très nettement améliorées par le traitement des PILCS par le BTMAC.

  9. Synthesis and characterization of microporous inorganic membranes for propylene/propane separation

    Science.gov (United States)

    Ma, Xiaoli

    Membrane-based gas separation is promising for efficient propylene/propane (C3H6/C3H8) separation with low energy consumption and minimum environment impact. Two microporous inorganic membrane candidates, MFI-type zeolite membrane and carbon molecular sieve membrane (CMS) have demonstrated excellent thermal and chemical stability. Application of these membranes into C3H6/C3H 8 separation has not been well investigated. This dissertation presents fundamental studies on membrane synthesis, characterization and C3H 6/C3H8 separation properties of MFI zeolite membrane and CMS membrane. MFI zeolite membranes were synthesized on α-alumina supports by secondary growth method. Novel positron annihilation spectroscopy (PAS) techniques were used to non-destructively characterize the pore structure of these membranes. PAS reveals a bimodal pore structure consisting of intracrystalline zeolitic micropores of ~0.6 nm in diameter and irregular intercrystalline micropores of 1.4 to 1.8 nm in size for the membranes. The template-free synthesized membrane exhibited a high permeance but a low selectivity in C3H 6/C3H8 mixture separation. CMS membranes were synthesized by coating/pyrolysis method on mesoporous gamma-alumina support. Such supports allow coating of thin, high-quality polymer films and subsequent CMS membranes with no infiltration into support pores. The CMS membranes show strong molecular sieving effect, offering a high C3H 6/C3H8 mixture selectivity of ~30. Reduction in membrane thickness from 500 nm to 300 nm causes an increase in C3H8 permeance and He/N2 selectivity, but a decrease in the permeance of He, N 2 and C3H6 and C3H6/C 3H8 selectivity. This can be explained by the thickness dependent chain mobility of the polymer film resulting in final carbon membrane of reduced pore size with different effects on transport of gas of different sizes, including possible closure of C3H6-accessible micropores. CMS membranes demonstrate excellent C3H6/C 3H8 separation

  10. Fast and efficient synthesis of microporous polymer nanomembranes via light-induced click reaction

    Science.gov (United States)

    An, Qi; Hassan, Youssef; Yan, Xiaotong; Krolla-Sidenstein, Peter; Mohammed, Tawheed; Lang, Mathias; Bräse, Stefan

    2017-01-01

    Conjugated microporous polymers (CMPs) are materials of low density and high intrinsic porosity. This is due to the use of rigid building blocks consisting only of lightweight elements. These materials are usually stable up to temperatures of 400 °C and are chemically inert, since the networks are highly crosslinked via strong covalent bonds, making them ideal candidates for demanding applications in hostile environments. However, the high stability and chemical inertness pose problems in the processing of the CMP materials and their integration in functional devices. Especially the application of these materials for membrane separation has been limited due to their insoluble nature when synthesized as bulk material. To make full use of the beneficial properties of CMPs for membrane applications, their synthesis and functionalization on surfaces become increasingly important. In this respect, we recently introduced the solid liquid interfacial layer-by-layer (LbL) synthesis of CMP-nanomembranes via Cu catalyzed azide–alkyne cycloaddition (CuAAC). However, this process featured very long reaction times and limited scalability. Herein we present the synthesis of surface grown CMP thin films and nanomembranes via light induced thiol–yne click reaction. Using this reaction, we could greatly enhance the CMP nanomembrane synthesis and further broaden the variability of the LbL approach.

  11. Fast and efficient synthesis of microporous polymer nanomembranes via light-induced click reaction.

    Science.gov (United States)

    An, Qi; Hassan, Youssef; Yan, Xiaotong; Krolla-Sidenstein, Peter; Mohammed, Tawheed; Lang, Mathias; Bräse, Stefan; Tsotsalas, Manuel

    2017-01-01

    Conjugated microporous polymers (CMPs) are materials of low density and high intrinsic porosity. This is due to the use of rigid building blocks consisting only of lightweight elements. These materials are usually stable up to temperatures of 400 °C and are chemically inert, since the networks are highly crosslinked via strong covalent bonds, making them ideal candidates for demanding applications in hostile environments. However, the high stability and chemical inertness pose problems in the processing of the CMP materials and their integration in functional devices. Especially the application of these materials for membrane separation has been limited due to their insoluble nature when synthesized as bulk material. To make full use of the beneficial properties of CMPs for membrane applications, their synthesis and functionalization on surfaces become increasingly important. In this respect, we recently introduced the solid liquid interfacial layer-by-layer (LbL) synthesis of CMP-nanomembranes via Cu catalyzed azide-alkyne cycloaddition (CuAAC). However, this process featured very long reaction times and limited scalability. Herein we present the synthesis of surface grown CMP thin films and nanomembranes via light induced thiol-yne click reaction. Using this reaction, we could greatly enhance the CMP nanomembrane synthesis and further broaden the variability of the LbL approach.

  12. Sn-PILC: A novel Efficient and Recyclable Catalyst for One-pot Three Component Povarov’s Inverse-electron-demand Hetero Diels-Alder Reaction for a Facile Synthesis of Tetrahydropyranoquinoline Derivatives under Neat Conditions

    Directory of Open Access Journals (Sweden)

    Megha Rai

    2016-07-01

    Full Text Available The Povarov’s inverse-electron-demand hetero Diels–Alder one-pot three components reaction of aromatic aldehyde, aromatic amine with DHF has been developed using Sn-PILC as a catalyst under a neat condition which may helpful to society to get pharmacologically more active compounds. In the present study a novel series of tetrahydroquinoline 4(a-f were synthesized and characterized by IR, 1HNMR, 13CNMR, Mass spectral analysis and elemental analysis. The synthetic details and characterization results are discussed. DOI: http://dx.doi.org/10.17807/orbital.v8i3.801

  13. Synthesis of Two-dimensional Microporous Carbonaceous Polymer Nanosheets and Their Application as High-performance CO2 Capture Sorbent.

    Science.gov (United States)

    Zhang, Miao; Liu, Lin; He, Teng; Wu, Guotao; Chen, Ping

    2016-06-21

    The synthesis of two-dimensional (2D) polymer nanosheets with a well-defined microporous structure remains challenging in materials science. Here, a new kind of 2D microporous carbonaceous polymer nanosheets was synthesized through polymerization of a very low concentration of 1,4-dicyanobenzene in molten zinc chloride at 400-500 °C. This type of nanosheets has a thickness in the range of 3-20 nm, well-defined microporosity, a high surface area (∼537 m(2)  g(-1) ), and a large micropore volume (∼0.45 cm(3)  g(-1) ). The microporous carbonaceous polymer nanosheets exhibit superior CO2 sorption capability (8.14 wt % at 298 K and 1 bar) and a relatively high CO2 selectivity toward N2 (25.6). Starting from different aromatic nitrile monomers, a variety of 2D carbonaceous polymer nanosheets can be obtained showing a certain universality of the ionothermal method reported herein.

  14. Lanthanum-catalysed synthesis of microporous 3D graphene-like carbons in a zeolite template

    Science.gov (United States)

    Kim, Kyoungsoo; Lee, Taekyoung; Kwon, Yonghyun; Seo, Yongbeom; Song, Jongchan; Park, Jung Ki; Lee, Hyunsoo; Park, Jeong Young; Ihee, Hyotcherl; Cho, Sung June; Ryoo, Ryong

    2016-07-01

    Three-dimensional graphene architectures with periodic nanopores—reminiscent of zeolite frameworks—are of topical interest because of the possibility of combining the characteristics of graphene with a three-dimensional porous structure. Lately, the synthesis of such carbons has been approached by using zeolites as templates and small hydrocarbon molecules that can enter the narrow pore apertures. However, pyrolytic carbonization of the hydrocarbons (a necessary step in generating pure carbon) requires high temperatures and results in non-selective carbon deposition outside the pores. Here, we demonstrate that lanthanum ions embedded in zeolite pores can lower the temperature required for the carbonization of ethylene or acetylene. In this way, a graphene-like carbon structure can be selectively formed inside the zeolite template, without carbon being deposited at the external surfaces. X-ray diffraction data from zeolite single crystals after carbonization indicate that electron densities corresponding to carbon atoms are generated along the walls of the zeolite pores. After the zeolite template is removed, the carbon framework exhibits an electrical conductivity that is two orders of magnitude higher than that of amorphous mesoporous carbon. Lanthanum catalysis allows a carbon framework to form in zeolite pores with diameters of less than 1 nanometre; as such, microporous carbon nanostructures can be reproduced with various topologies corresponding to different zeolite pore sizes and shapes. We demonstrate carbon synthesis for large-pore zeolites (FAU, EMT and beta), a one-dimensional medium-pore zeolite (LTL), and even small-pore zeolites (MFI and LTA). The catalytic effect is a common feature of lanthanum, yttrium and calcium, which are all carbide-forming metal elements. We also show that the synthesis can be readily scaled up, which will be important for practical applications such as the production of lithium-ion batteries and zeolite-like catalyst

  15. Molecular template-directed synthesis of microporous polymer networks for highly selective CO2 capture.

    Science.gov (United States)

    Shi, Yao-Qi; Zhu, Jing; Liu, Xiao-Qin; Geng, Jian-Cheng; Sun, Lin-Bing

    2014-11-26

    Porous polymer networks have great potential in various applications including carbon capture. However, complex monomers and/or expensive catalysts are commonly used for their synthesis, which makes the process complicated, costly, and hard to scale up. Herein, we develop a molecular template strategy to fabricate new porous polymer networks by a simple nucleophilic substitution reaction of two low-cost monomers (i.e., chloromethylbenzene and ethylene diamine). The polymerization reactions can take place under mild conditions in the absence of any catalysts. The resultant materials are interconnected with secondary amines and show well-defined micropores due to the structure-directing role of solvent molecules. These properties make our materials highly efficient for selective CO2 capture, and unusually high CO2/N2 and CO2/CH4 selectivities are obtained. Furthermore, the adsorbents can be completely regenerated under mild conditions. Our materials may provide promising candidates for selective capture of CO2 from mixtures such as flue gas and natural gas.

  16. Template-mediated Synthesis of Hollow Microporous Organic Nanorods with Tunable Aspect Ratio

    Science.gov (United States)

    Li, Qingyin; Jin, Shangbin; Tan, Bien

    2016-08-01

    Hollow microporous organic nanorods (HMORs) with hypercrosslinked polymer (HCPs) shells were synthesized through emulsion polymerization followed by hypercrosslinking. The HMORs have tunable aspect ratios, high BET surface areas and monodispersed morphologies, showing good performance in gas adsorpion.

  17. Hollow fibre microporous silica membranes for gas separation and pervaporation: synthesis, performance and stability

    NARCIS (Netherlands)

    Soest-Vercammen, E.L.J. van; Peters, T.A.; Fontalvo, J.; Vorstman, M.A.G.; Benes, N.E.; Dam, R.A. van; Vroon, Z.A.E.P.; Keurentjes, J.T.F.

    2005-01-01

    Thin microporous silica membranes were prepared on the outer surface of hollow fibre ceramic substrates. In principle this enables relatively fast and inexpensive production of large membrane surface area, combined with a low support resistance and a high membrane surface area/module volume ratio (>

  18. Synthesis and characterization of functional thienyl-phosphine microporous polymers for carbon dioxide capture.

    Science.gov (United States)

    Chen, Xianghui; Qiao, Shanlin; Du, Zhengkun; Zhou, Yuanhang; Yang, Renqiang

    2013-07-25

    A novel kind of functional organic microporous polymer is designed by introducing polar organic groups (P=O and P=S) and electron-rich heterocyclic into the framework to obtain high carbon dioxide capture capacity. The estimated Brunauer-Emmett-Teller (BET) surface areas of these polymers are about 600 m(2) g(-1) and the highest CO2 uptake is 2.26 mmol g(-1) (1.0 bar/273 K). Interestingly, the polymer containing P=O groups shows greater CO2 capture capacity than that containing P=S groups at the same temperature. In addition, these polymers show high isosteric heats of CO2 adsorption (28.6 kJ mol(-1) ), which can be competitive with some nitrogen-rich networks. Therefore, these microporous polymers are promising candidates for carbon dioxide capture.

  19. Aryl Gels and Related Materials. Synthesis and Characterization of a New Class of Microporous Materials

    Science.gov (United States)

    1994-08-16

    t.• ,.,-o, ,, e l,-e,Vsi0 " / "I "I~ 1. 00 0 -0el Silica Bridged Polysilsesquioxane Polysilsesquioxanes are molecular composites, hybrid...surface areas ranging from 400 to 700 m 2/g. The average pore size falls in the low mesopore to micropore domain (ន A). Molecular Determinants of...DSC and TGA analysis of alkylene bridged poiysilsesquioxanes are distinguished by the absence of a Tg. In addition, the onset of decomposition occurs

  20. Synthesis and gas adsorption properties of tetra-armed microporous organic polymer networks based on triphenylamine.

    Science.gov (United States)

    Yang, Xiao; Yao, Shuwen; Yu, Miao; Jiang, Jia-Xing

    2014-04-01

    Two novel tetra-armed microporous organic polymers have been designed and synthesized via a nickel-catalyzed Yamamoto-type Ullmann cross-coupling reaction or Suzuki cross-coupling polycondensation. These polymers are stable in various solvents, including concentrated hydrochloric acid, and are thermally stable. The homocoupled polymer YPTPA shows much higher Brunauer-Emmet-Teller-specific surface area up to 1557 m(2) g(-1) than the copolymer SPTPA (544 m(2) g(-1)), and a high CO2 uptake ability of 3.03 mmol g(-1) (1.13 bar/273 K) with a CO2 /N2 sorption selectivity of 17.3:1. Both polymers show high isosteric heats of CO2 adsorption (22.7-26.5 kJ mol(-1)) because the incorporation of nitrogen atoms into the skeleton of microporous organic polymers enhances the interaction between the pore wall and the CO2 molecules. The values are higher than those of the porous aromatic frameworks, which contain neither additional polar functional groups nor nitrogen atoms, and are rather close to those of previously reported microporous organic polymers containing the nitrogen atoms on the pore wall. These data show that these materials would be potential candidates for applications in post-combustion CO2 capture and sequestration technology. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  1. Controlled synthesis of conjugated microporous polymer films: versatile platforms for highly sensitive and label-free chemo- and biosensing.

    Science.gov (United States)

    Gu, Cheng; Huang, Ning; Gao, Jia; Xu, Fei; Xu, Yanhong; Jiang, Donglin

    2014-05-05

    Conjugated microporous polymers (CMPs), in which rigid building blocks form robust networks, are usually synthesized as insoluble and unprocessable powders. We developed a methodology using electropolymerization for the synthesis of thin CMP films. The thickness of these films is synthetically controllable, ranging from nanometers to micrometers, and they are obtained on substrates or as freestanding films. The CMP films combine a number of striking physical properties, including high porosity, extended π conjugation, facilitated exciton delocalization, and high-rate electron transfer. We explored the CMP films as versatile platforms for highly sensitive and label-free chemo- and biosensing of electron-rich and electron-poor arenes, metal ions, dopamine, and hypochloroic acid, featuring rapid response, excellent selectivity, and robust reusability.

  2. Synthesis and characterization of super-microporous material with enhanced hydrothermal stability

    Indian Academy of Sciences (India)

    Shujie Wu; Ke Song; Jingqi Guan; Qiubin Kan

    2011-07-01

    Super-microporouos silicon material with high hydrothermal stability denoted as MCM-41-T has been prepared from mesoporous MCM-41 by high temperature treatment. The structural and chemical property of MCM-41-T has been characterized by X-ray diffraction, transmission electron microscopy, N2 adsorption-desorption, infrared spectroscopy and 29Si MAS NMR. The characteristic results show that Si–OH groups are forced to condense by high temperature treatment, and the pore size of MCM-41-T is around 1.5 nm in the super-microporous range. Compared with the original material MCM-41, the hydrothermal stability of MCM-41-T has been significantly enhanced.

  3. One-Step Synthesis of Microporous Carbon Monoliths Derived from Biomass with High Nitrogen Doping Content for Highly Selective CO2 Capture

    Science.gov (United States)

    Geng, Zhen; Xiao, Qiangfeng; Lv, Hong; Li, Bing; Wu, Haobin; Lu, Yunfeng; Zhang, Cunman

    2016-08-01

    The one-step synthesis method of nitrogen doped microporous carbon monoliths derived from biomass with high-efficiency is developed using a novel ammonia (NH3)-assisted activation process, where NH3 serves as both activating agent and nitrogen source. Both pore forming and nitrogen doping simultaneously proceed during the process, obviously superior to conventional chemical activation. The as-prepared nitrogen-doped active carbons exhibit rich micropores with high surface area and high nitrogen content. Synergetic effects of its high surface area, microporous structure and high nitrogen content, especially rich nitrogen-containing groups for effective CO2 capture (i.e., phenyl amine and pyridine-nitrogen) lead to superior CO2/N2 selectivity up to 82, which is the highest among known nanoporous carbons. In addition, the resulting nitrogen-doped active carbons can be easily regenerated under mild conditions. Considering the outstanding CO2 capture performance, low production cost, simple synthesis procedure and easy scalability, the resulting nitrogen-doped microporous carbon monoliths are promising candidates for selective capture of CO2 in industrial applications.

  4. One-Step Synthesis of Microporous Carbon Monoliths Derived from Biomass with High Nitrogen Doping Content for Highly Selective CO2 Capture

    Science.gov (United States)

    Geng, Zhen; Xiao, Qiangfeng; Lv, Hong; Li, Bing; Wu, Haobin; Lu, Yunfeng; Zhang, Cunman

    2016-01-01

    The one-step synthesis method of nitrogen doped microporous carbon monoliths derived from biomass with high-efficiency is developed using a novel ammonia (NH3)-assisted activation process, where NH3 serves as both activating agent and nitrogen source. Both pore forming and nitrogen doping simultaneously proceed during the process, obviously superior to conventional chemical activation. The as-prepared nitrogen-doped active carbons exhibit rich micropores with high surface area and high nitrogen content. Synergetic effects of its high surface area, microporous structure and high nitrogen content, especially rich nitrogen-containing groups for effective CO2 capture (i.e., phenyl amine and pyridine-nitrogen) lead to superior CO2/N2 selectivity up to 82, which is the highest among known nanoporous carbons. In addition, the resulting nitrogen-doped active carbons can be easily regenerated under mild conditions. Considering the outstanding CO2 capture performance, low production cost, simple synthesis procedure and easy scalability, the resulting nitrogen-doped microporous carbon monoliths are promising candidates for selective capture of CO2 in industrial applications. PMID:27488268

  5. One-Step Synthesis of Microporous Carbon Monoliths Derived from Biomass with High Nitrogen Doping Content for Highly Selective CO2 Capture.

    Science.gov (United States)

    Geng, Zhen; Xiao, Qiangfeng; Lv, Hong; Li, Bing; Wu, Haobin; Lu, Yunfeng; Zhang, Cunman

    2016-08-04

    The one-step synthesis method of nitrogen doped microporous carbon monoliths derived from biomass with high-efficiency is developed using a novel ammonia (NH3)-assisted activation process, where NH3 serves as both activating agent and nitrogen source. Both pore forming and nitrogen doping simultaneously proceed during the process, obviously superior to conventional chemical activation. The as-prepared nitrogen-doped active carbons exhibit rich micropores with high surface area and high nitrogen content. Synergetic effects of its high surface area, microporous structure and high nitrogen content, especially rich nitrogen-containing groups for effective CO2 capture (i.e., phenyl amine and pyridine-nitrogen) lead to superior CO2/N2 selectivity up to 82, which is the highest among known nanoporous carbons. In addition, the resulting nitrogen-doped active carbons can be easily regenerated under mild conditions. Considering the outstanding CO2 capture performance, low production cost, simple synthesis procedure and easy scalability, the resulting nitrogen-doped microporous carbon monoliths are promising candidates for selective capture of CO2 in industrial applications.

  6. Microporous Polymers from a Carbazole-Based Triptycene Monomer: Synthesis and Their Applications for Gas Uptake.

    Science.gov (United States)

    Zhai, Tian-Long; Tan, Liangxiao; Luo, Yi; Liu, Jun-Min; Tan, Bien; Yang, Xiang-Liang; Xu, Hui-Bi; Zhang, Chun

    2016-01-01

    Two kinds of novel organic microporous polymers TCPs (TCP-A and TCP-B) were prepared by two cost-effective synthetic strategies from the monomer of tricarbazolyltriptycene (TCT). Their structure and properties were characterized by FT-IR, solid (13) C NMR, powder XRD, SEM, TEM, and gas absorption measurements. TCP-B displayed a high surface area (1469 m(2)  g(-1) ) and excellent H2 storage (1.70 wt % at 1 bar/77 K) and CO2 uptake abilities (16.1 wt % at 1 bar/273 K), which makes it a promising material for potential application in gas storage.

  7. Mutation of the conserved calcium-binding motif in Neisseria gonorrhoeae PilC1 impacts adhesion but not piliation.

    Science.gov (United States)

    Cheng, Yuan; Johnson, Michael D L; Burillo-Kirch, Christine; Mocny, Jeffrey C; Anderson, James E; Garrett, Christopher K; Redinbo, Matthew R; Thomas, Christopher E

    2013-11-01

    Neisseria gonorrhoeae PilC1 is a member of the PilC family of type IV pilus-associated adhesins found in Neisseria species and other type IV pilus-producing genera. Previously, a calcium-binding domain was described in the C-terminal domains of PilY1 of Pseudomonas aeruginosa and in PilC1 and PilC2 of Kingella kingae. Genetic analysis of N. gonorrhoeae revealed a similar calcium-binding motif in PilC1. To evaluate the potential significance of this calcium-binding region in N. gonorrhoeae, we produced recombinant full-length PilC1 and a PilC1 C-terminal domain fragment. We show that, while alterations of the calcium-binding motif disrupted the ability of PilC1 to bind calcium, they did not grossly affect the secondary structure of the protein. Furthermore, we demonstrate that both full-length wild-type PilC1 and full-length calcium-binding-deficient PilC1 inhibited gonococcal adherence to cultured human cervical epithelial cells, unlike the truncated PilC1 C-terminal domain. Similar to PilC1 in K. kingae, but in contrast to the calcium-binding mutant of P. aeruginosa PilY1, an equivalent mutation in N. gonorrhoeae PilC1 produced normal amounts of pili. However, the N. gonorrhoeae PilC1 calcium-binding mutant still had partial defects in gonococcal adhesion to ME180 cells and genetic transformation, which are both essential virulence factors in this human pathogen. Thus, we conclude that calcium binding to PilC1 plays a critical role in pilus function in N. gonorrhoeae.

  8. Calcium binding properties of the Kingella kingae PilC1 and PilC2 proteins have differential effects on type IV pilus-mediated adherence and twitching motility.

    Science.gov (United States)

    Porsch, Eric A; Johnson, Michael D L; Broadnax, Angela D; Garrett, Christopher K; Redinbo, Matthew R; St Geme, Joseph W

    2013-02-01

    Kingella kingae is an emerging bacterial pathogen that is being recognized increasingly as an important etiology of septic arthritis, osteomyelitis, and bacteremia, especially in young children. The pathogenesis of K. kingae disease begins with bacterial adherence to respiratory epithelium, which is dependent on type IV pili and is influenced by two PilC-like proteins called PilC1 and PilC2. Production of either PilC1 or PilC2 is necessary for K. kingae piliation and bacterial adherence. In this study, we set out to further investigate the role of PilC1 and PilC2 in type IV pilus-associated phenotypes. We found that PilC1 contains a functional 9-amino-acid calcium-binding (Ca-binding) site with homology to the Pseudomonas aeruginosa PilY1 Ca-binding site and that PilC2 contains a functional 12-amino-acid Ca-binding site with homology to the human calmodulin Ca-binding site. Using targeted mutagenesis to disrupt the Ca-binding sites, we demonstrated that the PilC1 and PilC2 Ca-binding sites are dispensable for piliation. Interestingly, we showed that the PilC1 site is necessary for twitching motility and adherence to Chang epithelial cells, while the PilC2 site has only a minor influence on twitching motility and no influence on adherence. These findings establish key differences in PilC1 and PilC2 function in K. kingae and provide insights into the biology of the PilC-like family of proteins.

  9. Synthesis and characterization of a new microporous cesium silicotitanate (SNL-B) molecular sieve

    Energy Technology Data Exchange (ETDEWEB)

    NYMAN,MAY D.; GU,B.X.; WANG,L.M.; EWING,R.C.; NENOFF,TINA M.

    2000-03-20

    Ongoing hydrothermal Cs-Ti-Si-O-H{sub 2}O phase investigations has produced several new ternary phases including a novel microporous Cs-silicotitanate molecular sieve, SNL-B with the approximate formula of Cs{sub 3}TiSi{sub 3}O{sub 9.5}{center_dot}3H{sub 2}O. SNL-B is only the second molecular sieve Cs-silicotitanate phase reported to have been synthesized by hydrothermal methods. Crystallites are very small (0.1 x 2 microns) with a blade-like morphology. SNL-B is confirmed to be a 3-dimensional molecular sieve by a variety of characterization techniques (N{sub 2} adsorption, ion exchange, water adsorption/desorption, solid state CP-MAS NMR). SNL-B is able to desorb and adsorb water from its pores while retaining its crystal structure and exchanges Cs cations readily. Additional techniques were used to describe fundamental properties (powder X-ray diffraction, FTIR, {sup 29}Si and {sup 133}/Cs MAS NMR, DTA, SEM/EDS, ion selectivity, and radiation stability). The phase relationships of metastable SNL-B to other hydrothermally synthesized Cs-Ti-Si-O-H{sub 2}O phases are discussed, particularly its relationship to a Cs-silicotitanate analogue of pharmacosiderite, and a novel condensed phase, a polymorph of Cs{sub 2}TiSi{sub 6}O{sub 15}(SNL-A).

  10. Synthesis of a novel β-ketoenamine-linked conjugated microporous polymer with Nsbnd H functionalized pore surface for carbon dioxide capture

    Science.gov (United States)

    Shuangzhi, Chai; Liu, Haohan; Zhang, Xue; Han, Yang; Hu, Nantao; Wei, Liangming; Cong, Fengsong; Wei, Hao; Wang, Lin

    2016-10-01

    A novel β-ketoenamine-linked conjugated microporous polymer (KECMP-1) was synthesized via Schiff base condensation between 1,3,5-triformylphloroglucinol and m-phenylenediamine by conventional solvothermal synthesis without a template or a metal catalyst. KECMP-1 exhibits a considerable Brunauer-Emmett-Teller specific surface area (691 m2 g-1) and high physicochemical stability. By utilizing the bottom-up strategy, the surfaces of the pore walls were covered with the Nsbnd H sites, together with their microporous structures, lead to the high carbon dioxide (CO2) adsorption capability (10.5 wt% at 273 K and 1.0 bar) and heat of adsorption (34.6 kJ mol-1).

  11. Facile synthesis of microporous carbon through a soft-template pathway and its performance in desulfurization and denitrogenation

    Institute of Scientific and Technical Information of China (English)

    Bo Sun; Gang Li; Xiaoxing Wang

    2010-01-01

    Wormlike/lamellar microporous carbons were prepared by using long alkyl chain primary amine hydrochloride as the template and resorcinol/formaldehyde as the carbon source under highly acidic conditions. The template can be eliminated by high temperature treatment under an inert atmosphere. The obtained carbon materials were characterized by N2 adsorption-desorption, transmission electron microscopy, thermogravimetry and scanning electron microscopy. The results show that dodecylamine hydrochloride surfactant can be used as the template of wormlike micropores structure while octadecylamine hydrochloride results in both lamellar and wormlike micropores. The obtained carbon materials have the similar pore size in the range of 0.5~0.59 nm, but with various morphologies such as monolith, spheres, and coralline. The microporous carbon obtained from dodecytamine hydrochloride surfactant shows good "adsorption performance to remove the refractory sulfur compounds and nitrogen-containing compounds in fuel.

  12. Synthesis of nitrogen doped microporous carbons prepared by activation-free method and their high electrochemical performance

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Ki-Seok [Department of Chemistry, Inha University, Incheon 402-751 (Korea, Republic of); Park, Soo-Jin, E-mail: sjpark@inha.ac.kr [Department of Chemistry, Inha University, Incheon 402-751 (Korea, Republic of)

    2011-11-30

    Graphical abstract: This describes the increase of specific capacitance in hybrid electrodes as a function of melamine content. Display Omitted Highlights: > For N-enriched hybrid carbons, co-precursors, PVDF/melamine composites, were used. > Microporous carbons were formed by only carbonization without chemical activation. > The nitrogen content of microporous carbons was controlled by melamine content. > N-doped carbons showed higher specific capacitance compared to microporous carbons. > It was attributed to the easy electron transfer and pseudocapacitance. - Abstract: Nitrogen-doped microporous carbons (N-MCs) were prepared by the carbonization of the polyvinylidene fluoride (PVDF)/melamine mixture without chemical activation. The electrochemical performance of the N-MCs was investigated as a function of PVDF/melamine ratio. It was found that, without additional activation, the N-MCs had a high specific surface area (greater than 560 m{sup 2}/g) because of the micropore formation by the release of fluorine groups. In addition, although the specific surface area decreased, nitrogen groups were increased with increasing melamine content, leading to an enhanced electrochemical performance. Indeed, the N-MCs showed a better electrochemical performance than that of microporous carbons (MCs) prepared by PVDF alone, and the highest specific capacitance (310 F/g) was obtained at a current density of 0.5 A/g, as compared to a value of 248 F/g for MCs. These results indicate that the microporous features of N-MC lead to feasible ion transfer during charge/discharge duration and the presence of nitrogen groups as strong electron donor on the N-MC electrode in electrolyte could provide a pseudocapacitance by the redox reaction.

  13. A microporous potassium vanadyl phosphate analogue of mahnertite. Hydrothermal synthesis and crystal structure

    Energy Technology Data Exchange (ETDEWEB)

    Yakubovich, Olga V. [M.V. Lomonosov Moscow State Univ. (Russian Federation). Dept. of Crystallography; Russian Academy of Science, Moscow (Russian Federation). Inst. of Geology of Deposits, Petrography, Mineralogy and Geochemistry; Steele, Ian M. [Notre Dame Univ., IN (United States). Notre Dame Integrated Imaging Facility; Kiriukhina, Galina V.; Dimitrova, Olga V. [M.V. Lomonosov Moscow State Univ. (Russian Federation). Dept. of Crystallography

    2015-09-01

    The novel phase K{sub 2.5}Cu{sub 5}Cl(PO{sub 4}){sub 4}(OH){sub 0.5}(VO{sub 2}).H{sub 2}O was prepared by hydrothermal synthesis at 553 K. Its crystal structure was determined using low-temperature (100 K) single-crystal synchrotron diffraction data and refined against F{sup 2} to R = 0.035. The compound crystallizes in the tetragonal space group I4/mmm, with unit-cell parameters a =9.8120(8), c = 19.954(1) Aa, V = 1921.1(2) Aa{sup 3}, and Z = 4. Both symmetrically independent Cu{sup 2+} sites show elongated square-pyramidal coordination. The V{sup 5+} ions reside in strongly distorted five-vertex VO{sub 5} polyhedra with 50% occupancy. The structure is based on a 3D anionic framework built from Cu- and V-centered five-vertex polyhedra and PO{sub 4} tetrahedra. Channels in the [100] and [010] directions accommodate large K atoms and H{sub 2}O molecules. The compound is a new structural representative of the topology shown by the lavendulan group of copper arsenate and phosphate minerals. Their tetragonal or pseudotetragonal crystal structures are characterized by two types of 2D slabs alternating along one axis of their unit cells. One slab, described by the formula [Cu{sub 4}X(TO{sub 4}){sub 4}]{sub 8} (where X = Cl, O and T = As, P), is common to all phases, whereas the slab content of the other set differs among the group members. We suggest interpreting this family of compounds in terms of the modular concept and also consider the synthetic phase Ba(VO)Cu{sub 4}(PO{sub 4}){sub 4} as a simplest member of this polysomatic series.

  14. "Stereoscopic" 2D super-microporous phosphazene-based covalent organic framework: Design, synthesis and selective sorption towards uranium at high acidic condition.

    Science.gov (United States)

    Zhang, Shuang; Zhao, Xiaosheng; Li, Bo; Bai, Chiyao; Li, Yang; Wang, Lei; Wen, Rui; Zhang, Meicheng; Ma, Lijian; Li, Shoujian

    2016-08-15

    So far, only five primary elements (C, H, O, N and B) and two types of spatial configuration (C2-C4, C6 and Td) are reported to build the monomers for synthesis of covalent organic frameworks (COFs), which have partially limited the route selection for accessing COFs with new topological structure and novel properties. Here, we reported the design and synthesis of a new "stereoscopic" 2D super-microporous phosphazene-based covalent organic framework (MPCOF) by using hexachorocyclotriphosphazene (a P-containing monomer in a C3-like spatial configuration) and p-phenylenediamine (a linker). The as-synthesized MPCOF shows high crystallinity, relatively high heat and acid stability and distinctive super-microporous structure with narrow pore-size distributions ranging from 1.0-2.1nm. The results of batch sorption experiments with a multi-ion solution containing 12 co-existing cations show that in the pH range of 1-2.5, MPCOF exhibits excellent separation efficiency for uranium with adsorption capacity more than 71mg/g and selectivity up to record-breaking 92%, and furthermore, an unreported sorption capacity (>50mg/g) and selectivity (>60%) were obtained under strong acidic condition (1M HNO3). Studies on sorption mechanism indicate that the uranium separation by MPCOF in acidic solution is realized mainly through both intra-particle diffusion and size-sieving effect.

  15. Synthesis of N-rich microporous carbon materials from chitosan by alkali activation using Na{sub 2}CO{sub 3}

    Energy Technology Data Exchange (ETDEWEB)

    Ilnicka, Anna; Lukaszewicz, Jerzy P., E-mail: jerzy_lukaszewicz@o2.pl

    2015-11-15

    Highlights: • The novel manufacturing procedure of nitrogen-rich carbon materials. • The biopolymer chitosan can be activated by sodium carbonate. • The effect of the addition of activator and the temperature of carbonization was investigated. • The N-rich carbon materials exhibit high specific surface area and microporous structure. - Abstract: The paper presents the first systematic study on the synthesis of nitrogen-rich nanoporous activated carbons by chitosan carbonization in the presence of a hard template (activator), i.e. Na{sub 2}CO{sub 3}. Carbonization process was carried out in the range of 600–900 °C under a flow of nitrogen. The effect of the addition of different volumes of activator and the temperature of carbonization on the development of specific surface area and pore structure (pore volume and median pore diameter) of the activated carbons was investigated. Additionally, the nitrogen content and nitrogen-containing surface species were determined by means of XPS and combustion elemental analysis. The nitrogen content was placed in the range of 2.4–13.1 wt.%. On the grounds of the low-temperature adsorption of nitrogen, it was found that obtained adsorption isotherms were of type-I, based on the IUPAC classification, which is typical for microporous materials.

  16. Hollow microporous organic capsules

    National Research Council Canada - National Science Library

    Li, Buyi; Yang, Xinjia; Xia, Lingling; Majeed, Muhammad Irfan; Tan, Bien

    2013-01-01

    Fabrication of hollow microporous organic capsules (HMOCs) could be very useful because of their hollow and porous morphology, which combines the advantages of both microporous organic polymers and non-porous nanocapsules...

  17. Synthesis and effect of physical aging on gas transport properties of a microporous polyimide derived from a novel spirobifluorene-based dianhydride

    KAUST Repository

    Ma, Xiaohua

    2015-02-17

    A novel generic method is reported for the synthesis of a spirobifluorene-based dianhydride (SBFDA). An intrinsically microporous polyimide was obtained by polycondensation reaction with 3,3′-dimethylnaphthidine (DMN). The corresponding polymer (SBFDA-DMN) exhibited good solubility, excellent thermal stability, as well as significant microporosity with high BET surface area of 686 m2/g. The O2 permeability of a methanol-treated and air-dried membrane was 1193 Barrer with a moderate O2/N2 selectivity of 3.2. The post-treatment history and aging conditions had great effects on the membrane performance. A significant drop in permeability coupled with an increase in selectivity was observed after long-term aging. After storage of 200 days, the gas separation properties of SBFDA-DMN were located slightly above the latest Robeson upper bounds for several gas pairs such as O2/N2 and H2/N2.

  18. Solvothermal Synthesis and Crystal Structure of a Zn(II) Microporous Metal-organic Framework%Solvothermal Synthesis and Crystal Structure of a Zn(II) Microporous Metal-organic Framework

    Institute of Scientific and Technical Information of China (English)

    LI Dong-Ping; LI Jing; LI Xu; CHEN Ping-Hua; JIAO Xiao-Yan; LI Yong-Xiu

    2012-01-01

    A novel three-dimensional Zn(II) coordination polymer, Zn3(C2H2N3)4(SiF6), has been synthesized under solvothermal conditions using 1H-1,2,4-triazole-3-carboxylic acid and zinc fluoride as the starting materials. The complex has been characterized by elemental analysis, IR, TG analysis and single-crystal X-ray diffraction analysis. The complex crystallizes in the tetragonal 14/mmm space group with a = 11.592(0), c = 7.526(1) A~, V= 1011.3(2)A3, Z = 2, M,. = 610.46, D, = 2.005 g/cm3 and F(000) = 596. The final R = 0.0312 and wR = 0.067 for 319 observed reflections with 1 〉 20(/). In the title complex, the Zn centers are interconnected by μ3-bridging triazole ligands to form a microporous three-dimensional metal-organic framework.

  19. Adsorption and oxidation of elemental mercury over Ce-MnOx/Ti-PILCs.

    Science.gov (United States)

    He, Chuan; Shen, Boxiong; Chen, Jianhong; Cai, Ji

    2014-07-15

    A series of innovative Ce-Mn/Ti-pillared-clay (Ce-Mn/Ti-PILC) catalysts combining the advantages of PILCs and Ce-Mn were investigated for elemental mercury (Hg0) capture at 100-350 °C in the absence of HCl in the flue gas. The fresh and used catalysts were characterized by scanning electron microscopy (SEM), nitrogen adsorption-desorption, X-ray diffraction (XRD), and X-ray photoelectron spectroscopy (XPS). The catalyst characterization indicated that the 6%Ce-6%MnOx/Ti-PILC catalyst possessed a large specific surface area and high dispersion of Ce and Mn on the surface. The experimental results indicated that the 6%Ce-6%MnOx/Ti-PILC catalyst exhibited high Hg0 capture (>90%) at 100-350 °C. During the first stage of the reaction, the main Hg0 capture mechanism for the catalyst was adsorption. As the reaction proceeded, the Hg0 oxidation ability was substantially enhanced. Both the hydroxyl oxygen and the lattice oxygen on the surface of the catalysts participated in Hg0 oxidation. At a low temperature (150 °C), the hydroxyl oxygen and lattice oxygen from Ce4+→Ce3+ and Mn3+→Mn2+ on the surface contributed to Hg0 oxidation. However, at a high temperature (250 °C), the hydroxyl oxygen and lattice oxygen from Mn4+→Mn3+ contributed to Hg0 oxidation. Hg0 oxidation was preferred at a high temperature. The 6%Ce-6%MnOx/Ti-PILC catalyst was demonstrated to a good Hg0 adsorbent and catalytic oxidant in the absence of HCl in the flue gas.

  20. Mn-CeOx/Ti-PILCs for selective catalytic reduction of NO with NH3 at low temperature.

    Science.gov (United States)

    Shen, Boxiong; Ma, Hongqing; Yao, Yan

    2012-01-01

    Titanium-pillared clays (Ti-PILCs) were obtained by different ways from TiCl4, Ti(OC3H7)4 and TiOSO4, respectively. Mn-CeO(x)/)Ti-PILCs were then prepared and their activities of selective catalytic reduction (SCR) of NO with NH3 at low-temperature were evaluated. Mn-CeO(x)/Ti-PILCs were characterized by X-ray diffraction, N2 adsorption, Fourier transform infrared spectroscopy, thermal analysis, temperature-programmed desorption of ammonia and H2-temperature-programmed reduction. It was found that Ti-pillar tend to be helpful for the enlargement of surface area, pore volume, acidity and the enhancement of thermal stability for Mn-CeO(x)/Ti-PILCs. Mn-CeO(x)/Ti-PILCs catalysts were active for the SCR of NO. Among three resultant Mn-CeO(x)/Ti-PILCs, the catalyst from TiOSO4 showed the highest activity with 98% NO conversion at 220 degrees C, it also exhibited good resistance to H2O and SO2 in flue gas. The catalyst from TiCl4 exhibited the lowest activity due to the unsuccessful pillaring process.

  1. Facile synthesis of triazine-triphenylamine-based microporous covalent polymer adsorbent for flue gas CO2 capture

    KAUST Repository

    Das, Swapan Kumar

    2017-07-17

    The sustainable capture and sequestration of CO2 from flue gas emission is an important and unavoidable challenge to control greenhouse gas release and climate change. In this report, we describe a triazine-triphenylamine-based microporous covalent organic polymer under mild synthetic conditions. 13C and 15N solid-state NMR and FTIR analyses confirm the linkage of the triazine and triphenylamine components in the porous polymer skeleton. The material is composed of spherical particles 1.0 to 2.0 μm in size and possesses a high surface area (1104 m2/g). The material exhibits superb chemical robustness under acidic and basic conditions and high thermal stability. Single-component gas adsorption exhibits an enhanced CO2 uptake of 3.12 mmol/g coupled with high sorption selectivity for CO2/N2 of 64 at 273 K and 1 bar, whereas the binary gas mixture breakthrough study using a model flue gas composition at 298 K shows a high CO2/N2 selectivity of 58. The enhanced performance is attributed to the high Lewis basicity of the framework, as it favors the interaction with CO2.

  2. Synthesis and Characterization of a Novel Microporous Dihydroxyl-Functionalized Triptycene-Diamine-Based Polyimide for Natural Gas Membrane Separation

    KAUST Repository

    Alaslai, Nasser Y.

    2017-07-10

    An intrinsically microporous polyimide is synthesized in m-cresol by a one-pot high-temperature condensation reaction of 4,4\\'-(hexafluoroisopropylidene)diphthalic anhydride (6FDA) and newly designed 2,6 (7)-dihydroxy-3,7(6)-diaminotriptycene (DAT1-OH). The 6FDA-DAT1-OH polyimide is thermally stable up to 440 °C, shows excellent solubility in polar solvents, and has moderately high Brunauer-Teller-Emmett (BET) surface area of 160 m2 g-1 , as determined by nitrogen adsorption at -196 °C. Hydroxyl functionalization applied to the rigid 3D triptycene-based diamine building block results in a polyimide that exhibits moderate pure-gas CO2 permeability of 70 Barrer combined with high CO2 /CH4 selectivity of 50. Mixed-gas permeation studies demonstrate excellent plasticization resistance of 6FDA-DAT1-OH with impressive performance as potential membrane material for natural gas sweetening with a CO2 permeability of 50 Barrer and CO2 /CH4 selectivity of 40 at a typical natural gas well partial pressure of 10 atm.

  3. Synthesis and Characterization of a Novel Microporous Dihydroxyl-Functionalized Triptycene-Diamine-Based Polyimide for Natural Gas Membrane Separation.

    Science.gov (United States)

    Alaslai, Nasser; Ma, Xiaohua; Ghanem, Bader; Wang, Yingge; Alghunaimi, Fahd; Pinnau, Ingo

    2017-07-10

    An intrinsically microporous polyimide is synthesized in m-cresol by a one-pot high-temperature condensation reaction of 4,4'-(hexafluoroisopropylidene)diphthalic anhydride (6FDA) and newly designed 2,6 (7)-dihydroxy-3,7(6)-diaminotriptycene (DAT1-OH). The 6FDA-DAT1-OH polyimide is thermally stable up to 440 °C, shows excellent solubility in polar solvents, and has moderately high Brunauer-Teller-Emmett (BET) surface area of 160 m(2) g(-1) , as determined by nitrogen adsorption at -196 °C. Hydroxyl functionalization applied to the rigid 3D triptycene-based diamine building block results in a polyimide that exhibits moderate pure-gas CO2 permeability of 70 Barrer combined with high CO2 /CH4 selectivity of 50. Mixed-gas permeation studies demonstrate excellent plasticization resistance of 6FDA-DAT1-OH with impressive performance as potential membrane material for natural gas sweetening with a CO2 permeability of 50 Barrer and CO2 /CH4 selectivity of 40 at a typical natural gas well partial pressure of 10 atm. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  4. INFLUENCIA DEL pH EN PROCESOS FOTO-FENTON UTILIZANDO Fe-PILCs COMO CATALIZADOR

    OpenAIRE

    Carolina Noya; Andrea De León; Marta Sergio; Juan Bussi

    2011-01-01

    En este trabajo se reporta la actividad catalítica de una arcilla pilareada con hierro (Fe-PILC) en la degradación de naranja de metilo mediante la técnica foto-Fenton heterogénea. Se prepararon Fe-PILCs a partir de una arcilla natural empleando diferentes temperaturas de calcinación: 350°C y 500°C. Los sólidos obtenidos se caracterizaron por análisis termogravimétrico y adsorción de nitrógeno, no observándose diferencias significativas de sus parámetros texturales (área específica y volumen ...

  5. One-step synthesis of a novel N-doped microporous biochar derived from crop straws with high dye adsorption capacity.

    Science.gov (United States)

    Lian, Fei; Cui, Guannan; Liu, Zhongqi; Duo, Lian; Zhang, Guilong; Xing, Baoshan

    2016-07-01

    N-doping is one of the most promising strategies to improve the adsorption capacity and selectivity of carbon adsorbents. Herein, synthesis, characterization and dye adsorption of a novel N-doped microporous biochar derived from direct annealing of crop straws under NH3 is presented. The resultant products exhibit high microporosity (71.5%), atomic percentage of nitrogen (8.81%), and adsorption capacity to dyes, which is about 15-20 times higher than that of original biochar. Specifically, for the sample NBC800-3 pyrolyzed at 800°C in NH3 for 3 h, its adsorption for acid orange 7 (AO7, anionic) and methyl blue (MB, cationic) is up to 292 mg g(-1) and 436 mg g(-1), respectively, which is among the highest ever reported for carbonaceous adsorbents. The influences of N-doping and porous structure on dye adsorption of the synthesized carbons are also discussed, where electrostatic attraction, π-π electron donor-accepter interaction, and Lewis acid-base interaction mainly contribute to AO7 adsorption, and surface area (especially pore-filling) dominates MB adsorption. The N-doped biochar can be effectively regenerated and reused through direct combustion and desorption approaches.

  6. EXTRUIDOS DE AlFe-PILC EN LA OXIDACIÓN CATALÍTICA DE FENOL

    Directory of Open Access Journals (Sweden)

    Nancy R. Sanabria

    2010-09-01

    Full Text Available Extruidos de AlFe-PILC con forma de cilindro compacto se emplearon como catalizadores en la reacción de oxidación de fenol en medio acuoso. Debido a que el proceso de elaboración de los extruidos con fase activa AlFe-PILC afecta la actividad intrínseca del catalizador, en este trabajo se determinaron la resistencia mecánica y la estabilidad química del catalizador conformado, así como las limitaciones difusionales por efecto de la aglomeración. Los extruidos se elaboraron con la proporción másica 42/28/30 de arcilla intercalada con AlFe, aglomerante (mezcla 50/50 de bentonita sódica y cálcica y agua, exhibiendo elevada resistencia mecánica y estabilidad química a la inmersión en agua. Los extruidos de AlFe-PILC presentaron un factor de efectividad menor a 1; por tanto, la reacción se encuentra limitada por la difusión intrapartícula.

  7. Saccharide-derived microporous spherical biochar prepared from hydrothermal carbonization and different pyrolysis temperatures: synthesis, characterization, and application in water treatment.

    Science.gov (United States)

    Tran, Hai Nguyen; Lee, Chung-Kung; Nguyen, Tien Vinh; Chao, Huan-Ping

    2017-08-24

    Three saccharides (glucose, sucrose, and xylose) were used as pure precursors for synthesizing spherical biochars (GB, SB, and XB), respectively. The two-stage synthesis process comprised: (1) the hydrothermal carbonization of saccharides to produce spherical hydrochar' and (2) pyrolysis of the hydrochar at different temperatures from 300°C to 1200°C. The results demonstrated that the pyrolysis temperatures insignificantly affected the spherical morphology and surface chemistry of biochar. The biochar' isoelectric point ranged from 2.64 to 3.90 (abundant oxygen-containing functionalities). The Brunauer-Emmett-Teller (BET)-specific surface areas (SBET) and total pore volumes (Vtotal) of biochar increased with the increasing pyrolysis temperatures. The highest SBET and Vtotal were obtained at a pyrolysis temperature of 900°C for GB (775 m(2)/g and 0.392 cm(3)/g), 500°C for SB (410 m(2)/g and 0.212 cm(3)/g), and 600°C for XB (426 m(2)/g and 0.225 cm(3)/g), respectively. The spherical biochar was a microporous material with approximately 71-98% micropore volume. X-ray diffraction results indicated that the biochar' structure was predominantly amorphous. The spherical biochar possessed the graphite structure when the pyrolysis temperature was higher than 600°C. The adsorption capacity of GB depended strongly on the pyrolysis temperature. The maximum Langmuir adsorption capacities ([Formula: see text]) of 900GB exhibited the following selective order: phenol (2.332 mmol/g) > Pb(2+) (1.052 mmol/g) > Cu(2+) (0.825 mmol/g) > methylene green 5 (0.426 mmol/g) > acid red 1 (0.076 mmol/g). This study provides a simple method to prepare spherical biochar - a new and potential adsorbent for adsorbing heavy metals and aromatic contaminants.

  8. Microporous polymeric materials

    Directory of Open Access Journals (Sweden)

    Peter M Budd

    2004-04-01

    Full Text Available Microporous materials are solids that contain interconnected pores of molecular dimensions (i.e. <2 nm. Such materials possess large surface areas, typically 300-1500 m2 g−1, and are of great technological importance for adsorption and heterogeneous catalysis1. There are two main classes of microporous materials widely used in industry: crystalline zeolites (aluminosilicates and activated carbons. In the past decade, there has been an intense effort to optimize the porosity of these materials for various applications2,3. However, it is recognized that the design of entirely new microporous materials would open up exciting opportunities for fundamental research and industrial applications3.

  9. INFLUENCIA DEL pH EN PROCESOS FOTO-FENTON UTILIZANDO Fe-PILCs COMO CATALIZADOR

    Directory of Open Access Journals (Sweden)

    Carolina Noya

    2011-01-01

    Full Text Available En este trabajo se reporta la actividad catalítica de una arcilla pilareada con hierro (Fe-PILC en la degradación de naranja de metilo mediante la técnica foto-Fenton heterogénea. Se prepararon Fe-PILCs a partir de una arcilla natural empleando diferentes temperaturas de calcinación: 350°C y 500°C. Los sólidos obtenidos se caracterizaron por análisis termogravimétrico y adsorción de nitrógeno, no observándose diferencias significativas de sus parámetros texturales (área específica y volumen de poros. Se estudió la influencia del pH del medio en el proceso catalítico y se verificó que la remoción de naranja de metilo fue efectiva a pH 3 pero no a pH 6. Este comportamiento puede explicarse por cambios en la polaridad de la molécula del colorante que afectan su adsorción sobre la arcilla. A pH 3 se estudió además la influencia de diferentes factores sobre el proceso catalítico.

  10. Catalytic oxidation with Al-Ce-Fe-PILC as a post-treatment system for coffee wet processing wastewater.

    Science.gov (United States)

    Sanabria, Nancy R; Peralta, Yury M; Montañez, Mardelly K; Rodríguez-Valencia, Nelson; Molina, Rafael; Moreno, Sonia

    2012-01-01

    The effluent from the anaerobic biological treatment of coffee wet processing wastewater (CWPW) contains a non-biodegradable compound that must be treated before it is discharged into a water source. In this paper, the wet hydrogen peroxide catalytic oxidation (WHPCO) process using Al-Ce-Fe-PILC catalysts was researched as a post-treatment system for CWPW and tested in a semi-batch reactor at atmospheric pressure and 25 °C. The Al-Ce-Fe-PILC achieved a high conversion rate of total phenolic compounds (70%) and mineralization to CO(2) (50%) after 5 h reaction time. The chemical oxygen demand (COD) of coffee processing wastewater after wet hydrogen peroxide catalytic oxidation was reduced in 66%. The combination of the two treatment methods, biological (developed by Cenicafé) and catalytic oxidation with Al-Ce-Fe-PILC, achieved a 97% reduction of COD in CWPW. Therefore, the WHPCO using Al-Ce-Fe-PILC catalysts is a viable alternative for the post-treatment of coffee processing wastewater.

  11. Microporous niobia-silica membrane with very low CO2 permeability

    NARCIS (Netherlands)

    Boffa, V.; ten Elshof, J.E.; Petukhov, A.V.; Blank, D.H.A.

    2008-01-01

    A sol-gel-derived microporous ceramic membrane with an exceptionally low permeability for CO2 from gaseous streams was developed and characterized. The sols were prepared from a mixture of niobium and silicon alkoxide precursors by acid-catalyzed synthesis. Microporous films were formed by coating a

  12. Microporous Niobia-Silica Membrane with Very Low CO2 Permeability

    NARCIS (Netherlands)

    Boffa, Vittorio; Elshof, ten Johan E.; Petukhov, Andrei V.; Blank, Dave H.A.

    2008-01-01

    A sol-gel-derived microporous ceramic membrane with an exceptionally low permeability for CO2 from gaseous streams was developed and characterized. The sols were prepared from a mixture of niobium and silicon alkoxide precursors by acid-catalyzed synthesis. Microporous films were formed by coating a

  13. Physicochemical properties of vanadium impregnated Al-PILCs: Effect of vanadium source

    Energy Technology Data Exchange (ETDEWEB)

    Balci, Suna, E-mail: sunabalci@gazi.edu.tr; Tecimer, Aylin

    2015-03-01

    Graphical abstract: - Highlights: • Vanadium was incorporated into Al-PILC using NaVO{sub 3} or VOSO{sub 4}·3H{sub 2}O precursors by wet impregnation, washing after wet impregnation and impregnation from solution methods. • The layered structure of the supports was retained after the vanadium incorporation. • Incorporation took place both by settling and ion exchange mechanism with the treatment VOSO{sub 4}·3H{sub 2}O precursor while settling was dominant in the use of NaVO{sub 3} precursor. • Treatment with VOSO{sub 4}·3H{sub 2}O which was acidic in solution resulted in more structural deformation. • V{sub 2}O{sub 5} and VO{sub 2} were found as the major oxide forms on the impregnated samples. Loading of vanadyl sulfate hydrate (VOSO{sub 4}·H{sub 2}O) resulted in higher V/Si ratio. Most of the vanadium was bonded in +5 oxide form. • Changes in the FTIR signals after vanadium incorporation caused by Brønsted and Lewis sites, silanol, water and vanadium vibrations were occured. • Dehydroxylation of the structure took place around 300 °C. Samples obtained by impregnation and washing after wet impregnation methods resulted in similar mass losses and the wet impregnated sample showed the highest mass loss among the impregnated samples. - Summary: Clay from the Middle Anatolian previously pillared by Al{sub 13}-Keggin ions and then calcined at 300 °C (Al-PILC) was impregnated with aqueous solutions of vanadium precursors by impregnation from solution (I), wet impregnation (WI) and washing after wet impregnation (WWI) methods. The crystal and textural properties were evaluated by X-ray powder diffraction (XRD), nitrogen sorption and transmission electron microscopy (TEM) images. Vanadium incorporation into the Al-PILC resulted decreases in the basal spacing from 1.75 nm to 1.35 nm with the preserved typical layered structure. The use of sodium metavanadate (NaVO{sub 3}) as the source and the impregnation from solution as the incorporation method

  14. Fractal dimension and energetic heterogeneity of gold-modified Al-Fe-Ce pilc's

    Energy Technology Data Exchange (ETDEWEB)

    Carriazo, J.G.; Molina, R. [Estado Solido y Catalisis Ambiental (ESCA), Departamento de Quimica, Facultad de Ciencias, Universidad Nacional de Colombia, Carrera 30 No. 45-03, Bogota (Colombia); Moreno, S. [Estado Solido y Catalisis Ambiental (ESCA), Departamento de Quimica, Facultad de Ciencias, Universidad Nacional de Colombia, Carrera 30 No. 45-03, Bogota (Colombia)], E-mail: smorenog@unal.edu.co

    2008-12-30

    This paper studies the energetic and topographical changes that occur on the surface of a series of clays pillared with the mixed Al-Fe-Ce system and on the surface of solids synthesized by the deposition of gold nanoparticles over these pillared clays. The energetic heterogeneity of the solids was analyzed by means of the distribution of the adsorption potential, while the variations in the fractal dimension were determined from the nitrogen adsorption isotherms at 77 K, using the equation proposed by Avnir-Jaroniec. Results show the generation of microporous structures with important topographical modifications indicating an increase in the roughness (fractal geometry) of the surface of the solids as a consequence of the pillaring, revealing a positive effect of cerium addition in the synthesis process and the possible formation of nanoparticles of iron species and gold on the surface of pillared clays. The solids were also analyzed by transmission electron microscopy (TEM), confirming the formation of nanoparticles on the surface.

  15. DESHIDROGENACIÓN OXIDATIVA DE PROPANO POR FOSFATOS DE TIERRAS RARAS SOPORTADOS SOBRE PILC-AL

    Directory of Open Access Journals (Sweden)

    Carolina De Los Santos

    2012-01-01

    Full Text Available Se presenta la actividad catalítica en la deshidrogenación oxidativa de propano de diferentes fosfatos de tierra rara LnPO 4 (donde Ln = La, Ce, Pr, Nd, Sm y de los mismos soportados sobre una arcilla pilareada con aluminio de alta superficie específica. Los sólidos fueron caracterizados por ATG, DR X, adsorción de nitrógeno y análisis inmediato post reacción para determinar la eventual formación de carbón superficial. Los ensayos catalíticos usando como mezcla de reacción C 3 H 8 /O 2 /Ar = 10/10/80 se hicieron a temperaturas entre 400ºC y 600ºC. Todos los catalizadores fuer on activos. Los principales productos de reacción fueron: H 2 , CO, CO 2 , CH 4 , C 2 H 4 y C 3 H 6 , no detectándose compuestos orgánicos oxigenados. Aunque todos los sistemas investigados fueron activos, los catalizadores soportados sobre PILC-Al presentaron una actividad mayor que los másicos, siendo el mayor efecto para el samario en que el rendimiento a 600oC aumenta del 4% al 10%. Este efecto fue atribuido al incremento en el área superficial específica.

  16. Highly Selective Bifunctional Luminescent Sensor toward Nitrobenzene and Cu(2+) Ion Based on Microporous Metal-Organic Frameworks: Synthesis, Structures, and Properties.

    Science.gov (United States)

    Yang, Lirong; Lian, Chen; Li, Xuefei; Han, Yuyang; Yang, Lele; Cai, Ting; Shao, Caiyun

    2017-05-24

    Two metal-organic frameworks (MOFs), namely, [Ni(DTP)(H2O)]n (I) and [Cd2(DTP)2(bibp)1.5]n (II) (H2DPT = 4'-(4-(3,5-dicarboxylphenoxy) phenyl)-4,2':6',4″-terpyridine; bibp = 1,3-di(1H-imidazol-1-yl)propane), that present structural diversity were solvothermally prepared. Single-crystal X-ray diffraction analysis indicates that they consist of {NiN2O4} building units (for I) and {CdO4N2} and {CdO3N3} building units (for II), which are further linked by multicarboxylate H2DPT to construct microporous three-dimensional frameworks. The remarkable character of these frameworks is that coordination polymer II demonstrates highly selective and sensitive bifunctional luminescent sensor toward nitrobenzene and Cu(2+) ion. The fluorescence quenching mechanism of II caused by nitrobenzene is ascribed to electron transfer from electron-rich (II) to electron-deficient nitrobenzene. The result was also evidenced by the density functional theory. Furthermore, anti-ferromagnetic as well as electrochemical characters of Ni-MOF (I) were also investigated in this paper.

  17. Synthesis and kinetics investigation of meso-microporous Cu-SAPO-34 catalysts for the selective catalytic reduction of NO with ammonia.

    Science.gov (United States)

    Liu, Jixing; Yu, Fuhong; Liu, Jian; Cui, Lifeng; Zhao, Zhen; Wei, Yuechang; Sun, Qianyao

    2016-10-01

    A series of meso-microporous Cu-SAPO-34 catalysts were successfully synthesized by a one-pot hydrothermal crystallization method, and these catalysts exhibited excellent NH3-SCR performance at low temperature. Their structure and physic chemical properties were characterized by means of X-ray diffraction patterns (XRD), Scanning electron microscopy (SEM), Transmission electron microscopy (TEM), N2 sorption-desorption, nuclear magnetic resonance (NMR), Inductively Coupled Plasma-Atomic Emission spectrometer (ICP-AES), X-ray absorption spectroscopy (XPS), Temperature-programmed desorption of ammonia (NH3-TPD), Ultraviolet visible diffuse reflectance spectroscopy (UV-Vis DRS) and Temperature programmed reduction (TPR). The analysis results indicate that the high activities of Cu-SAPO-34 catalysts could be attributed to the enhancement of redox property, the formation of mesopores and the more acid sites. Furthermore, the kinetic results verify that the formation of mesopores remarkably reduces diffusion resistance and then improves the accessibility of reactants to catalytically active sites. The 1.0-Cu-SAPO-34 catalyst exhibited the high NO conversion (>90%) among the wide activity temperature window in the range of 150-425°C.

  18. Synthesis, characterization and rate capability performance of the micro-porous MnO{sub 2} nanowires as cathode material in lithium batteries

    Energy Technology Data Exchange (ETDEWEB)

    R, Ranjusha; S, Sonia T.; S, Roshny; V, Lakshmi [Nano Solar Division, Amrita Centre for Nanosciences, Kochi 682 041 (India); Kalluri, Sujith [Institute for Superconducting and Electronic Materials, University of Wollongong, New South Wales 2500 (Australia); Kim, Taik Nam [Department of Materials Engineering, Paichai University, Daejeon 302-735 (Korea, Republic of); Nair, Shantikumar V. [Nano Solar Division, Amrita Centre for Nanosciences, Kochi 682 041 (India); Balakrishnan, A., E-mail: avinash.balakrishnan@gmail.com [Nano Solar Division, Amrita Centre for Nanosciences, Kochi 682 041 (India)

    2015-10-15

    Graphical abstract: Translating MnO{sub 2} nanowires as cathode materials in coin cell and studying their discharge behavior and cycling stability at different C-rates. - Highlights: • MnO{sub 2} nanowires have been synthesized via hydrothermal route. • The nanowires were employed as cathode materials in Li-batteries. • Discharge and cycling stability were studied at different C-rates. • Specific capacity and power density of 251 mAh g{sup −1} and 200 W kg{sup −1} were attained. - Abstract: A peculiar architecture of one-dimensional MnO{sub 2} nanowires was synthesized by an optimized hydrothermal route and has been lucratively exploited to fabricate highly efficient microporous electrode overlays for lithium batteries. These fabricated electrodes comprised of interconnected nanoscale units with wire-shaped profile which exhibits high aspect ratio in the order of 10{sup 2}. Their outstanding intercalation/de-intercalation prerogatives have also been studied to fabricate lithium coin cells which revealed a significant specific capacity and power density of 251 mAh g{sup −1} and 200 W kg{sup −1}, respectively. A detailed electrochemical study was performed to elucidate how surface morphology and redox reaction behaviors underlying these electrodes influence the cyclic behavior of the electrode. Rate capability tests at different C-rates were performed to evaluate the capacity and cycling performance of these coin cells.

  19. A facile approach to the synthesis of non-porous and microporous sub-micron spherical zirconia and alumina-zirconia solid solution.

    Science.gov (United States)

    Ghotbi, Mohammad Yeganeh; Nasiri, Vida; Rafiee, Mehdi

    2013-01-01

    Amorphous monodisperse sub-micron spherical zirconia and alumina/zirconia solid solution particles were prepared by hydrolysis of zirconium and aluminum salts in ethanol. The heat-treatment process of the amorphous materials in air atmosphere at 500°C for 2h leaded to the production of non-porous zirconia and alumina/zirconia solid solution in tetragonal phase. The alkaline etching process of the as-prepared alumina/zirconia solid solution resulted in the formation of mono-modal microporous material with specific surface area of 125.0 m(2) g(-1) in comparison with 2. 9m(2) g(-1) for the parent material. Thermal analysis of the solid solution revealed that the incorporation of aluminum ions in the zirconia structure has decreased the phase transformation temperature from amorphous to crystalline structure. Moreover, optical study confirmed the presence of oxygen vacancy defect by substitution of tetravalent cations, Zr(4+) by trivalent cations, Al(3+) in zirconia lattice.

  20. Emulsification using microporous membranes

    Directory of Open Access Journals (Sweden)

    Goran T. Vladisavljević

    2011-10-01

    Full Text Available Membrane emulsification is a process of injecting a pure dispersed phase or pre-emulsion through a microporous membrane into the continuous phase. As a result of the immiscibility of the two phases, droplets of the dispersed phase are formed at the outlets of membrane pores. The droplets formed in the process are removed from the membrane surface by applying cross-flow or stirring of the continuous phase or using a dynamic (rotating or vibrating membrane. The most commonly used membrane for emulsification is the Shirasu Porous Glass (SPG membrane, fabricated through spinodal decomposition in a melt consisting of Japanese volcanic ash (Shirasu, boric acid and calcium carbonate. Microsieve membranes are increasingly popular as an alternative to highly tortuous glass and ceramic membranes. Microsieves are usually fabricated from nickel by photolithography and electroplating or they can be manufactured from silicon nitride via Reactive Ion Etching (RIE. An advantage of microsieves compared to the SPG membrane is in much higher transmembrane fluxes and higher tolerance to fouling by the emulsion ingredients due to the existence of short, straight through pores. Unlike conventional emulsification devices such as high-pressure valve homogenisers and rotor-stator devices, membrane emulsification devices permit a precise control over the mean pore size over a wide range and during the process insignificant amount of energy is dissipated as heat. The drop size is primarily determined by the pore size, but it depends also on other parameters, such as membrane wettability, emulsion formulation, shear stress on the membrane surface, transmembrane pressure, etc.

  1. Effect of chromium oxide as active site over TiO2-PILC for selective catalytic oxidation of NO.

    Science.gov (United States)

    Zhang, Jingxin; Zhang, Shule; Cai, Wei; Zhong, Qin

    2013-12-01

    This study introduced TiO2-pillared clays (TiO2-PILC) as a support for the catalytic oxidation of NO and analyzed the performance of chromium oxides as the active site of the oxidation process. Cr-based catalysts were prepared by a wet impregnation method. It was found that the 10 wt.% chromium doping on the support achieved the best catalytic activity. At 350 degrees C, the NO conversion was 61% under conditions of GHSV = 23600 hr(-1). The BET data showed that the support particles had a mesoporous structure. H2-TPR showed that Cr(10)TiP (10 wt.% Cr doping on TiO2-PILC) clearly exhibited a smooth single peak. EPR and XPS were used to elucidate the oxidation process. During the NO + O2 adsorption, the intensity of evolution of superoxide ions (O2(-)) increased. The content of Cr3+ on the surface of the used catalyst was 40.37%, but when the used catalyst continued adsorbing NO, the Cr3+ increased to 50.28%. Additionally, O(alpha)/O(beta) increased markedly through the oxidation process. The NO conversion decreased when SO2 was added into the system, but when the SO2 was removed, the catalytic activity recovered almost up to the initial level. FT-IR spectra did not show a distinct characteristic peak of SO4(2-).

  2. Microporous Silica Based Membranes for Desalination

    Directory of Open Access Journals (Sweden)

    João C. Diniz da Costa

    2012-09-01

    Full Text Available This review provides a global overview of microporous silica based membranes for desalination via pervaporation with a focus on membrane synthesis and processing, transport mechanisms and current state of the art membrane performance. Most importantly, the recent development and novel concepts for improving the hydro-stability and separating performance of silica membranes for desalination are critically examined. Research into silica based membranes for desalination has focussed on three primary methods for improving the hydro-stability. These include incorporating carbon templates into the microporous silica both as surfactants and hybrid organic-inorganic structures and incorporation of metal oxide nanoparticles into the silica matrix. The literature examined identified that only metal oxide silica membranes have demonstrated high salt rejections under a variety of feed concentrations, reasonable fluxes and unaltered performance over long-term operation. As this is an embryonic field of research several target areas for researchers were discussed including further improvement of the membrane materials, but also regarding the necessity of integrating waste or solar heat sources into the final process design to ensure cost competitiveness with conventional reverse osmosis processes.

  3. Synthesis of microporous material faujasite-type from kaolin waste; Sintese de material microporoso do tipo faujasita a partir de rejeito de caulim

    Energy Technology Data Exchange (ETDEWEB)

    Hildebrando, E.A.; Valenzuela-Diaz, F.R., E-mail: edemarino@usp.b [Universidade de Sao Paulo (USP), SP (Brazil). Dept. de Engenharia Metalurgica e de Materiais. Lab. de Materias-Primas Particuladas e Solidos nao Metalicos; Angelica, R.S. [Universidade Federal do Para (UFPA), Belem, PA (Brazil). Inst. de Geociencias. Fac. de Geologia; Neves, R.F. [Universidade Federal do Para (UFPA), Belem, PA (Brazil). Inst. de Tecnologia. Fac. de Engenharia Quimica

    2010-07-01

    Zeolite with structure faujasite was synthesized using kaolin waste from kaolin processing industries for paper coating as predominant source of silicon and aluminum; the starting material was characterized by XRF, XRD, DTA/TG, SEM, and products obtained by XRD and SEM. Synthesis in hydrothermal conditions occurred on autoclave and time-temperature effects, as well as the relationship Si/Al were considered. The results show that the methodology developed with the waste of calcined kaolin reacting at 90 deg C for 20 hours in an alkaline medium, in the presence of an additional source of silica was obtained zeolite Y as single phase present in the product. (author)

  4. Methods for synthesizing microporous crystals and microporous crystal membranes

    Energy Technology Data Exchange (ETDEWEB)

    Dutta, Prabir; Severance, Michael; Sun, Chenhu

    2017-02-07

    A method of making a microporous crystal material, comprising: a. forming a mixture comprising NaOH, water, and one or more of an aluminum source, a silicon source, and a phosphate source, whereupon the mixture forms a gel; b. heating the gel for a first time period, whereupon a first volume of water is removed from the gel and micoroporous crystal nuclei form, the nuclei having a framework; and c.(if a membrane is to be formed) applying the gel to a solid support seeded with microporous crystals having a framework that is the same as the framework of the nuclei; d. heating the gel for a second time period. during which a second volume of water is added to the gel; wherein the rate of addition of the second volume of water is between about 0.5 and about 2.0 fold the rate of removal of the first volume of water.

  5. Methods for synthesizing microporous crystals and microporous crystal membranes

    Science.gov (United States)

    Dutta, Prabir; Severance, Michael; Sun, Chenhu

    2017-02-07

    A method of making a microporous crystal material, comprising: a. forming a mixture comprising NaOH, water, and one or more of an aluminum source, a silicon source, and a phosphate source, whereupon the mixture forms a gel; b. heating the gel for a first time period, whereupon a first volume of water is removed from the gel and micoroporous crystal nuclei form, the nuclei having a framework; and c.(if a membrane is to be formed) applying the gel to a solid support seeded with microporous crystals having a framework that is the same as the framework of the nuclei; d. heating the gel for a second time period. during which a second volume of water is added to the gel; wherein the rate of addition of the second volume of water is between about 0.5 and about 2.0 fold the rate of removal of the first volume of water.

  6. Phenomenon of Structural Transformation of Ethylenediamine-Oriented Synthesis of Microporous Cobalt Phosphate%乙二胺导向合成的微孔晶体磷酸钴的转化现象

    Institute of Scientific and Technical Information of China (English)

    罗倩倩; 周世东; 任元; 李牛; 黄志鹏; 关乃佳; 项寿鹤

    2013-01-01

    Microporous cobalt phosphate structures can be synthesized using ethylenediamine as a structure directing agent. During the syntheses of CoPO-en-1, CoPO-en-2, CoPO-en-3, and CoPO-en-4, it was found that they could interconvert during hydrothermal or calcination conditions. CoPO-en-2 and CoPO-en-4 are the crystallization intermediates of CoPO-en-1 and CoPO-en-3, respectively. During hydrothermal synthesis, CoPO-en-2 and CoPO-en-4 could be obtained at lower temperature or higher temperature during the initial crystallization stage. Extended synthesis time at higher temperature the two former structures transform into the two latter. CoPO-en-2, CoPO-en-3, and CoPO-en-4 could also convert to CoPO-en-1 during calcination, and these transformations indicated the sequence of structure stability. During synthesis under hydrothermal conditions, CoPO-en-2, CoPO-en-3, and CoPO-en-4 could convert to CoPO-en-1. During muffle furnace roasting, CoPO-en-2, CoPO-en-3, and CoPO-en-4 could also convert to CoPO-en-1. Different structures in the liquid or solid phases could be transformed into the same structure using different approaches.%  以乙二胺为模板剂(SDA)合成微孔晶体磷酸钴,可以得到多种不同的结构.本文在合成四种不同结构类型的微孔磷酸钴(命名为CoPO-en-1, CoPO-en-2, CoPO-en-3, CoPO-en-4, en为乙二胺的英文缩写)过程中发现,它们之间不仅可以在水热合成条件下相互转化,在焙烧处理条件下也能实现转化.研究发现,在水热合成过程中, CoPO-en-2、CoPO-en-4分别是CoPO-en-1、CoPO-en-3的晶化中间物,在较低晶化温度下或者较高温度的晶化初期,可以发现它们的身影.一旦晶化温度升高或者晶化时间延长,它们就分别转化为CoPO-en-1和CoPO-en-3.在合成产物的热处理过程中发现:CoPO-en-2、CoPO-en-3、CoPO-en-4都能够通过焙烧转化为CoPO-en-1.这种现象表明,几种微孔磷酸钴结构间的稳定性存在递变关系.

  7. Characterization of Microporous Insulation, Microsil

    Energy Technology Data Exchange (ETDEWEB)

    Thomas, R. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)

    2017-06-15

    Microsil microporous insulation has been characterized by Lawrence Livermore National Laboratory for possible use in structural and thermal applications in the DPP-1 design. Qualitative test results have provided mechanical behavioral characteristics for DPP-1 design studies and focused on the material behavioral response to being crushed, cyclically loaded, and subjected to vibration for a confined material with an interference fit or a radial gap. Quantitative test results have provided data to support the DPP-1 FEA model analysis and verification and were used to determine mechanical property values for the material under a compression load. The test results are documented within this report.

  8. Methyllithium-Doped Naphthyl-Containing Conjugated Microporous Polymer with Enhanced Hydrogen Storage Performance.

    Science.gov (United States)

    Xu, Dan; Sun, Lei; Li, Gang; Shang, Jin; Yang, Rui-Xia; Deng, Wei-Qiao

    2016-06-01

    Hydrogen storage is a primary challenge for using hydrogen as a fuel. With ideal hydrogen storage kinetics, the weak binding strength of hydrogen to sorbents is the key barrier to obtain decent hydrogen storage performance. Here, we reported the rational synthesis of a methyllithium-doped naphthyl-containing conjugated microporous polymer with exceptional binding strength of hydrogen to the polymer guided by theoretical simulations. Meanwhile, the experimental results showed that isosteric heat can reach up to 8.4 kJ mol(-1) and the methyllithium-doped naphthyl-containing conjugated microporous polymer exhibited an enhanced hydrogen storage performance with 150 % enhancement compared with its counterpart naphthyl-containing conjugated microporous polymer. These results indicate that this strategy provides a direction for design and synthesis of new materials that meet the US Department of Energy (DOE) hydrogen storage target.

  9. Organic microporous materials and their interactions with different gases

    Energy Technology Data Exchange (ETDEWEB)

    Shepodd, T.J.; Miller, D.L. [Sandia National Labs., Livermore, CA (United States). Materials Chemistry Dept.; Lagasse, R.R. [Sandia National Labs., Albuquerque, NM (United States). Organic Materials Processing Dept.

    1997-04-01

    This work explored the interactions of various organic microporous materials with different gases. The authors were attempting to make substances that could separate gases through differential adsorption or store gases at reduced pressures. They synthesized xerogels that were highly crosslinked, allowing relatively large amounts of micro- and mesopores within the organic polymers. The monomers were polymerized in a solvent which was removed forming xerogels. Then exhaustive drying was performed to yield the tested microporous materials. The xerogels were exposed to four gases to observe their gas adsorption affinities (methane, carbon dioxide, hydrogen, and isobutane). For each microporous polymer the authors measured BET surface area, nitrogen isotherm, bulk density, pycnometric density, and equilibrium gas adsorption. Pore volume and pore size distribution were also calculated for some samples. Adsorption characteristics paralleled, but were not directly proportional to surface area or pore size distribution changes. Changes in adsorption magnitude and selectivity have been made through various formulations and derivatization. Increasing polarity showed increased affinities towards carbon dioxide, slightly increased affinities towards isobutane, and unchanged affinities towards methane and hydrogen. These materials could adsorb significant amounts of gas; about half the amount of some commercial carbons. Considering the minimal processing involved in their synthesis, these materials could be cost effective replacements for carbons in low-cost applications where high adsorption efficiencies are not a priority.

  10. Microporous metal organic framework [M{sub 2}(hfipbb){sub 2}(ted)] (M=Zn, Co; H{sub 2}hfipbb=4,4-(hexafluoroisopropylidene)-bis(benzoic acid); ted=triethylenediamine): Synthesis, structure analysis, pore characterization, small gas adsorption and CO{sub 2}/N{sub 2} separation properties

    Energy Technology Data Exchange (ETDEWEB)

    Xu, William W. [Department of Chemistry and Chemical Biology, Rutgers University, Piscataway, NJ 0854 (United States); Princeton High School, 151 Moore Street, Princeton, NJ 08540 (United States); Pramanik, Sanhita [Department of Chemistry and Chemical Biology, Rutgers University, Piscataway, NJ 0854 (United States); Zhang, Zhijuan [Department of Chemistry and Chemical Biology, Rutgers University, Piscataway, NJ 0854 (United States); Department of Chemistry and Chemical Engineering, South China University of Technology, Guangzhou 510641 (China); Emge, Thomas J. [Department of Chemistry and Chemical Biology, Rutgers University, Piscataway, NJ 0854 (United States); Li, Jing, E-mail: jingli@rutgers.edu [Department of Chemistry and Chemical Biology, Rutgers University, Piscataway, NJ 0854 (United States)

    2013-04-15

    Carbon dioxide is a greenhouse gas that is a major contributor to global warming. Developing methods that can effectively capture CO{sub 2} is the key to reduce its emission to the atmosphere. Recent research shows that microporous metal organic frameworks (MOFs) are emerging as a promising family of adsorbents that may be promising for use in adsorption based capture and separation of CO{sub 2} from power plant waste gases. In this work we report the synthesis, crystal structure analysis and pore characterization of two microporous MOF structures, [M{sub 2}(hfipbb){sub 2}(ted)] (M=Zn (1), Co (2); H{sub 2}hfipbb=4,4-(hexafluoroisopropylidene)-bis(benzoic acid); ted=triethylenediamine). The CO{sub 2} and N{sub 2} adsorption experiments and IAST calculations are carried out on [Zn{sub 2}(hfipbb){sub 2}(ted)] under conditions that mimic post-combustion flue gas mixtures emitted from power plants. The results show that the framework interacts with CO{sub 2} strongly, giving rise to relatively high isosteric heats of adsorption (up to 28 kJ/mol), and high adsorption selectivity for CO{sub 2} over N{sub 2}, making it promising for capturing and separating CO{sub 2} from CO{sub 2}/N{sub 2} mixtures. - Graphical abstract: Microporous [Zn{sub 2}(hfipbb){sub 2}(ted)] demonstrates high adsorption selectivity for CO{sub 2} over N{sub 2} under conditions that mimic flue gas mixtures. Highlights: ► Two new porous MOFs were synthesized and characterized by rational design. ► The small pore size leads to greatly enhanced CO{sub 2}–MOF interaction. ► High adsorption selectivity of the Zn–MOF for CO{sub 2} over N{sub 2} is achieved.

  11. Microporous metal organic framework [M2(hfipbb)2(ted)] (M=Zn, Co; H2hfipbb=4,4-(hexafluoroisopropylidene)-bis(benzoic acid); ted=triethylenediamine): Synthesis, structure analysis, pore characterization, small gas adsorption and CO2/N2 separation properties

    Science.gov (United States)

    Xu, William W.; Pramanik, Sanhita; Zhang, Zhijuan; Emge, Thomas J.; Li, Jing

    2013-04-01

    Carbon dioxide is a greenhouse gas that is a major contributor to global warming. Developing methods that can effectively capture CO2 is the key to reduce its emission to the atmosphere. Recent research shows that microporous metal organic frameworks (MOFs) are emerging as a promising family of adsorbents that may be promising for use in adsorption based capture and separation of CO2 from power plant waste gases. In this work we report the synthesis, crystal structure analysis and pore characterization of two microporous MOF structures, [M2(hfipbb)2(ted)] (M=Zn (1), Co (2); H2hfipbb=4,4-(hexafluoroisopropylidene)-bis(benzoic acid); ted=triethylenediamine). The CO2 and N2 adsorption experiments and IAST calculations are carried out on [Zn2(hfipbb)2(ted)] under conditions that mimic post-combustion flue gas mixtures emitted from power plants. The results show that the framework interacts with CO2 strongly, giving rise to relatively high isosteric heats of adsorption (up to 28 kJ/mol), and high adsorption selectivity for CO2 over N2, making it promising for capturing and separating CO2 from CO2/N2 mixtures.

  12. Mn-CeOx/Ti-PILC的制备、表征及脱硝性能研究%Study on preparation, characterization and de-NO activity of Mn-CeOx/Ti-PILC

    Institute of Scientific and Technical Information of China (English)

    沈伯雄; 马宏卿; 杨晓燕; 姚燕

    2012-01-01

    Titania-pillared clay (Ti-PILC) was prepared from butyltitanate, then Mn-CeOx/Ti-PILC was prepared by impregnating method on the Ti-PILC. The catalysts were characterized by BET, FT-IR, XRD, XPS and NH3-TPD. The results showed that, the pillaring process was efficient. Active components exist in Mn2O3 and CeO2 in catalyst Mn-CeOx/Ti-PILC which was a porous mesopore material with high BET surface area (133.7 m2/g), the activity test also indicted that this catalyst had good de-NOx activity, the removal efficiency could reach 83.1% even at 180 ℃.%采用钛酸丁酯溶胶法制备了钛基柱撑黏土(Ti-PILC),通过浸渍法制备Mn-CeOx/Ti-PILC,运用BET、FT-IR、XRD、NH3-TPD、XPS等技术对催化剂进行表征分析.结果说明,经过钛交联柱撑制备的Mn-CeOx/Ti-PILC是一种具备较大比表面积(133.7 m2/g)的多孔性介孔材料;活性成分主要为CeO2以及Mn2O3.Mn-CeOx/Ti-PILC低温下具有较好的选择性能催化剂还原(SCR)脱硝活性,180℃下,脱硝活性达到83.1%.

  13. 前驱物对Mn-Ce/Ti-PILC低温SCR脱硝的影响%Study on the effect of Mn-Ce/Ti-PILC on low temperature SCR activity prepared with different precursors

    Institute of Scientific and Technical Information of China (English)

    杨晓燕; 沈伯雄; 马宏卿; 刘亭; 左琛

    2012-01-01

    Titania - pillared clay ( Ti-PILC) was obatined with two different Ti precursors of TiCl4 and Ti(OC3H7)4; with Ti-PILC as support, Mn-Ce/Ti-PILCs catalysts were prepared through impregnation. The catalytic activity of Mn-Ce/Ti-PILCs in low temperature SCR of NO with NH3 was investigated. XRD, BET, FT-IR, NHj-TPD and SEM measurements indicated that the pillaring process can change the structure of the clay; compared with the original clay, the specific surface area, the pore volume and the acidity of Ti-PILCs are increased; meanwhile, Mn-Ce/Ti-PILCs also exhibits higher catalytic activity than Mn-Ce/clay. Moreover, Ti( OC3H7 )4 as Ti precursor is more effective in enhancing the catalytic activity of Mn-Ce/Ti-PILCs than TiCl4.%分别采用TiCl4和钛酸丁酯为Ti前驱物制备了钛基交联黏土(Ti-PILC),通过浸渍法将锰铈负载于Ti-PILC上,制得催化剂Mn-Ce/Ti-PILCs和Mn-Ce/clay,测试了该催化剂在以氨气为还原剂的低温SCR过程中的催化活性,分析了Ti前驱物对黏土结构及催化性能的影响.XRD、BET、FT-IR、NH3-TPD和SEM等表征结果表明,与原土(clay)相比,经钛交联柱撑后,Ti-PILC的微观结构更加合理,其比表面积和孔容都有了一定程度的增加,表面酸性有所增强.与原土负载的Mn-Ce/clay催化剂相比,Mn-Ce/Ti-PILCs的催化活性明显提高.而且,钛酸丁酯作前驱物进行交联比TiCl4交联效果更明显,所得到的催化剂低温活性更好.

  14. Burned Microporous Alumina-Graphite Brick

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    @@ 1 Scope This standard specifies the definition,classifica-tion,technical requirements,test methods,inspection rules,marking,packing,transportation and quality certificate of burned microporous alumina-graphite brick.

  15. Novel Microporous Films and Their Composites

    Directory of Open Access Journals (Sweden)

    P.C. Wu, Ph.D

    2007-04-01

    Full Text Available Cost-effective microporous films and composites can be made by using polyolefinic material and inorganic fillers. These microporous films and their composites can be designed and manufactured at high speed using commercial equipment for disposable hygiene articles, protective health care garments, building construction and many other industrial applications where air and moisture breathability is needed. The theory, formulations and methods of making these cost-effective polyolefinic-calcium carbonate compositions are discussed. Special engineering fibers and their fabrics can be combined with these novel microporous films to achieve a variety of properties for practical applications. However, one should keep intellectual property considerations in mind when contemplating the manufacture of microporous film products, their companies and their applications.

  16. Novel Microporous Films and Their Composites

    OpenAIRE

    P.C. Wu, Ph.D; Greg Jones, Ph.D; Chris Shelley, Ph.D; Bert Woelfli, Ph.D

    2007-01-01

    Cost-effective microporous films and composites can be made by using polyolefinic material and inorganic fillers. These microporous films and their composites can be designed and manufactured at high speed using commercial equipment for disposable hygiene articles, protective health care garments, building construction and many other industrial applications where air and moisture breathability is needed. The theory, formulations and methods of making these cost-effective polyolefinic-calcium ...

  17. Mesoporous and microporous titania membranes

    NARCIS (Netherlands)

    Sekulic-Kuzmanovic, Jelena

    2004-01-01

    The research described in this thesis deals with the synthesis and properties of ceramic oxide membrane materials. Since most of the currently available inorganic membranes with required separation properties have limited reliability and long-term stability, membranes made of new oxide materials tha

  18. 21 CFR 177.2250 - Filters, microporous polymeric.

    Science.gov (United States)

    2010-04-01

    ... as Components of Articles Intended for Repeated Use § 177.2250 Filters, microporous polymeric. Microporous polymeric filters identified in paragraph (a) of this section may be safely used, subject to the... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Filters, microporous polymeric. 177.2250 Section...

  19. A Perylene-Based Microporous Coordination Polymer Interacts Selectively with Electron-Poor Aromatics.

    Science.gov (United States)

    Tran, Ly D; Ma, Jialiu; Wong-Foy, Antek G; Matzger, Adam J

    2016-04-11

    The design, synthesis, and properties of the new microporous coordination polymer UMCM-310 are described. The unique electronic character of the perylene-based linker enables selective interaction with electron-poor aromatics leading to efficient separation of nitroaromatics. UMCM-310 possesses high surface area and large pore size and thus permits the separation of large organic molecules based on adsorption rather than size exclusion.

  20. Lithographically defined microporous carbon-composite structures

    Energy Technology Data Exchange (ETDEWEB)

    Burckel, David Bruce; Washburn, Cody M.; Lambert, Timothy N.; Finnegan, Patrick Sean; Wheeler, David R.

    2016-12-06

    A microporous carbon scaffold is produced by lithographically patterning a carbon-containing photoresist, followed by pyrolysis of the developed resist structure. Prior to exposure, the photoresist is loaded with a nanoparticulate material. After pyrolysis, the nanonparticulate material is dispersed in, and intimately mixed with, the carbonaceous material of the scaffold, thereby yielding a carbon composite structure.

  1. INFLUENCE OF SYNTHESIS PARAMETERS ON MORPHOLOGICAL PROPERTIES OF ALUMINUM(III-PILLARED BENTONITES

    Directory of Open Access Journals (Sweden)

    ANA-MARIA GEORGESCU

    2016-10-01

    Full Text Available Al-pillared interlayered clays (Al-PILCs have been prepared from Romanian natural calcium bentonite (Orasu Nou deposit and the effect of some parameters on the morphological properties has been investigated. The synthesis of Al-pillared bentonite consists in the following five steps: bentonite purification, ionic exchange of bentonite with Cu(II ions, preparation of pillaring agent, intercalation of ionic exchanged bentonite with pillaring agent and calcination. The pillared clays present a rigid structure, a high thermal stability given by the oxido-metallic pillars formed after calcination. The raw material and the obtained nanomaterials were characterized by scanning electron microscopy (SEM coupled with energy-dispersive X-ray spectroscopy (EDX and transmission electron microscopy (TEM. The intercalation of the Al-polyhydroxocations into the interlayer of montmorillonite strongly modified the morphology of the Al-PILCs. The material with the best characteristics will be chosen in the aim of its using in liquid effluents remediation.

  2. Bimodal micropore size distribution in active carbons

    Energy Technology Data Exchange (ETDEWEB)

    Vartapetyan, R.S.; Voloshchuk, A.M.; Limonov, N.A.; Romanov, Y.A. (Russian Academy of Sciences, Moscow (Russian Federation). Inst. of Physical Chemistry)

    1993-03-01

    The porous structure of active carbon was compared with that of the original mineral coal and its carbonization products. The parameters of the porous structure were calculated from the adsorption isotherms of CO[sub 2] (298 K) and H[sub 2]O (293 K). It was shown that carbonization of the original coal at 1120 K causes changes in the chemical composition, consolidation of the part which is amorphous to X-rays, generation of an ordered defect-containing structure on its basis, an increase in the volume of the micropores, and a decrease in the mean diameter. Activation of the carbonized coal affords a microporous structure with a bimodal size distribution.

  3. Method for making a microporous membrane

    Science.gov (United States)

    Gavalas, Lillian Susan (Inventor)

    2013-01-01

    A method for making a microporous membrane comprises the steps of: providing a plurality of carbon nanotubes having a hollow interior diameter of 20 Angstroms or less; sonicating the plurality of carbon nanotubes utilizing a solution comprising deionized, distilled water and a surfactant that coats at least one of the plurality of carbon nanotubes; collecting the coated carbon nanotubes; forming a matrix that supports the plurality of carbon nanotubes; embedding the coated carbon nanotubes into the matrix; rinsing the coated nanotubes to remove at least a portion of the surfactant; curing the nanotube-matrix assembly; and cutting the nanotube-matrix assembly to a particular thickness so as to open the ends of the embedded nanotubes. The hollow interiors of the plurality of embedded carbon nanotubes comprise the pores of the microporous membrane.

  4. Formation Mechanism of Micropores on the Surface of Pure Aluminum Induced by High-Current Pulsed Electron Beam Irradiation

    Institute of Scientific and Technical Information of China (English)

    ZOU Yang; CAI Jie; WAN Ming-Zhen; LV Peng; GUAN Qing-Feng

    2011-01-01

    The mechanism of micropores formed on the surface of polycrystalline pure aluminum under high-current pulsed electron beam (HCPEB) irradiation is explained. It is discovered that dispersed micropores with sizes of 0.1-1μm on the irradiated surface of pure aluminum can be successfully fabricated after HCPEB irradiation. The dominant formation mechanism of the surface micropores should be attributed to the formation of supersaturation vacancies within the near surface during the HCPEB irradiation and the migration of vacancies along gra,in boundaries and/or dislocations towards the irradiated surface. It is expected that the HCPEB technique will become a new method for the rapid synthesis of surface porous materials.%The mechanism of micropores formed on the surface of polycrystalline pure aluminum under high-current pulsed electron beam (HCPEB) irradiation is explained.It is discovered that dispersed micropores with sizes of 0.1-1μm on the irradiated surface of pure aluminum can be successfully fabricated after HCPEB irradiation.The dominant formation mechanism of the surface micropores should be attributed to the formation of supersaturation vacancies within the near surface during the HCPEB irradiation and the migration of vacancies along grain boundaries and/or dislocations towards the irradiated surface.It is expected that the HCPEB technique will become a new method for the rapid synthesis of surface porous materials.High-current pulsed electron beams (HCPEBs)have attracted much attention in the field of material surface modification.[1-7] During the transient bombardment process a high energy (108-109 W·cm-2) is deposited only in a very thin layer (less than tens of micrometers) within a very short time (a few microseconds) and thereby causes ultrafast heating and cooling on the irradiated surface of materials.The dynamic stress fields induced in these processes can induce intense deformation on the material surface.

  5. Pd-Cu-Ti-PILC上丙烯选择催化还原NO的活性研究%Pd-Cu-Ti-PILC for selective catalytic reduction of NO by propylene

    Institute of Scientific and Technical Information of China (English)

    陆光; 马国辉; 曲振平; 李新勇

    2015-01-01

    Cu-Ti-PILC and Pd/Cu-Ti-PILC catalysts were prepared using ion exchange strategy and used for selective catalytic reduction ( SCR ) of NO by propylene. The influences of Pd species on catalyst structure and catalytic performance were investigated by XRD,TPR,NO-TPD and C3 H6-SCR. The results of XRD showed that Pd destroyed interlayer arrangement of clay and did not change the interlayer distance of Ti-PILC. TPR results showed that Pd changed the redox of Cu species. NO-TPD results showed that Pd increased the nitrate amount. The results of C3 H6-SCR showed that Pd improved the N2 yield over Cu-Ti-PILC.%采用浸渍法制备Cu-Ti-PILC和Pd/Cu-Ti-PILC催化剂,结合X射线衍射谱( XRD)、程序升温还原( TPR)、NO程序升温脱附( NO-TPD)、丙烯选择催化还原NO( C3 H6-SCR)研究Pd组分对Cu-Ti-PILC催化剂结构和催化还原NO能力的影响。 XRD结果表明,Pd物种破坏了蒙脱土的层间排列但未改变Ti-PILC的层间距;TPR结果表明, Pd改变Cu-Ti-PILC催化剂表面上铜物种的还原性能;NO-TPD结果表明,Pd组分提高催化剂化学吸附NO;C3 H6-SCR结果显示Pd物种能够提高Cu-Ti-PILC催化效果。

  6. Transport Properties of Fluids in Micropores by Molecular Dynamics Simulation

    Institute of Scientific and Technical Information of China (English)

    LIU, Ying-Chun(刘迎春); WANG, Qi(王琦); Lü, Ling-Hong(吕玲红)

    2004-01-01

    The transport properties of fluid argon in micropores, i.e. diffusivity and viscosity, were studied by molecular dynamics simulations. The effects of pore width, temperature and density on diffusivity and viscosity were analyzed in micropores with pore widths from 0.8 to 4.0 nm. The results show that the diffusivity in micropores is much lower than the bulk diffusivity, and it decreases as the pore width decreases; but the viscosity in micropores is significantly larger than the bulk one, and it increases sharply in narrow micropores. The diffusivity in channel parallel direction is obviously larger than that in channel perpendicular direction. The temperature and density are important factors that obviously affect diffusivity and viscosity in micropores.

  7. Synthesis and Characterisation of Aluminophosphate Molecular Sieves

    Energy Technology Data Exchange (ETDEWEB)

    Halvorsen, E.N.

    1996-02-01

    Catalysts are very important in petrochemical processes. One of the properties that make crystalline, microporous materials attractive for catalytic purposes is their well-defined structure and ability to act as shape selective catalysts. This doctoral thesis presents the synthesis and characterization of a number of crystalline, microporous aluminophosphates and silicoaluminophosphates. 99 refs., 50 figs., 12 tabs.

  8. Emerging functional chiral microporous materials: synthetic strategies and enantioselective separations

    Directory of Open Access Journals (Sweden)

    Ming Xue

    2016-11-01

    Full Text Available In recent years, chiral microporous materials with open pores have attracted much attention because of their potential applications in enantioselective separation and catalysis. This review summarizes the recent advances on chiral microporous materials, such as metal-organic frameworks (MOFs, hydrogen-bonded organic frameworks (HOFs and covalent organic frameworks (COFs. We will introduce the synthetic strategies in detail and highlight the current status of chiral microporous materials on solid enantioselective adsorption, chiral chromatography resolution and membrane separation.

  9. Micropores and methods of making and using thereof

    Energy Technology Data Exchange (ETDEWEB)

    Perroud, Thomas D.; Patel, Kamlesh D.; Meagher, Robert J.

    2016-08-02

    Disclosed herein are methods of making micropores of a desired height and/or width between two isotropic wet etched features in a substrate which comprises single-level isotropic wet etching the two features using an etchant and a mask distance that is less than 2.times. a set etch depth. Also disclosed herein are methods using the micropores and microfluidic devices comprising the micropores.

  10. Proximate analysis for determination of micropores in granulated activated carbon

    Energy Technology Data Exchange (ETDEWEB)

    Berman, Ya. G.; Nikolaev, V.B.; Shepelev, A.N.

    1987-02-01

    A method is discussed for determining the specific micropore volume of granulated activated carbon used for water treatment in Soviet coking plants. Toluene molecules with a diameter of 0.67 nm are sorbed by activated carbon with micropore diameter ranging from 0.7 to 1.4 nm. Therefore, sorptive properties of activated carbon in relation to toluene supply information on micropore volume in carbon. A formula which describes this relation is derived. The method for determining micropore volume on the basis of toluene adsorption was tested using 8 types of activated carbon produced from coal and petroleum. Types of activated carbon characterized by the highest adsorption were selected. 1 ref.

  11. Solvent-resistant microporous polymide membranes

    Science.gov (United States)

    Miller, Warren K.; McCray, Scott B.; Friesen, Dwayne T.

    1998-01-01

    An asymmetric microporous membrane with exceptional solvent resistance and highly desirable permeability is disclosed. The membrane is made by a solution-casting or solution-spinning process from a copolyamic acid comprising the condensation reaction product in a solvent of at least three reactants selected from certain diamines and dianhydrides and post-treated to imidize and in some cases cross-link the copolyamic acid. The membrane is useful as an uncoated membrane for ultrafiltration, microfiltration, and membrane contactor applications, or may be used as a support for a permselective coating to form a composite membrane useful in gas separations, reverse osmosis, nanofiltration, pervaporation, or vapor permeation.

  12. Attractive forces in microporous carbon electrodes for capacitive deionization

    NARCIS (Netherlands)

    Biesheuvel, P.M.; Porada, S.; Levi, M.; Bazant, M.Z.

    2014-01-01

    The recently developed modified Donnan (mD) model provides a simple and useful description of the electrical double layer in microporous carbon electrodes, suitable for incorporation in porous electrode theory. By postulating an attractive excess chemical potential for each ion in the micropores

  13. Microporous calcium phosphate ceramics driving osteogenesis through surface architecture

    NARCIS (Netherlands)

    Zhang, J.; Barbieri, D.; Hoopen, ten H.W.M.; Bruijn, de J.D.; Blitterswijk, van C.A.; Yuan, H.

    2015-01-01

    The presence of micropores in calcium phosphate (CaP) ceramics has shown its important role in initiating inductive bone formation in ectopic sites. To investigate how microporous CaP ceramics trigger osteoinduction, we optimized two biphasic CaP ceramics (i.e., BCP-R and BCP-S) to have the same che

  14. Towards high water permeability in triazine-framework-based microporous membranes for dehydration of ethanol.

    Science.gov (United States)

    Tang, Yu Pan; Wang, Huan; Chung, Tai Shung

    2015-01-01

    The microstructural evolution of a series of triazine framework-based microporous (TFM) membranes under different conditions has been explored in this work. The pristine TFM membrane is in situ fabricated in the course of polymer synthesis via a facile Brønsted-acid-catalyzed cyclotrimerizaiton reaction. The as-synthesized polymer exhibits a microporous network with high thermal stability. The free volume size of the TFM membranes gradually evolved from a unimodal distribution to a bimodal distribution under annealing, as analyzed by positron annihilation lifetime spectroscopy (PALS). The emergence of the bimodal distribution is probably ascribed to the synergetic effect of quenching and thermal cyclization reaction. In addition, the fractional free volume (FFV) of the membranes presents a concave trend with increasing annealing temperature. Vapor sorption tests reveal that the mass transport properties are closely associated with the free volume evolution, which provides an optimal condition for dehydration of biofuels. A promising separation performance with extremely high water permeability has been attained for dehydration of an 85 wt % ethanol aqueous solution at 45 °C. The study on the free volume evolution of the TFM membranes may provide useful insights about the microstructure and mass transport behavior of the microporous polymeric materials.

  15. Tuning the Surface Polarity of Microporous Organic Polymers for CO2 Capture.

    Science.gov (United States)

    Chen, Jian; Li, He; Zhong, Mingmei; Yang, Qihua

    2017-09-05

    CO2 capture is very important to reduce the CO2 concentration in atmosphere. Herein, we report the preparation of microporous polymers with tunable surface polarity for CO2 capture. Porous polymers functionalized with -NH2 , -SO3 H, and -SO3 Li have been successfully prepared by using a post-synthesis modification of microporous polymers (P-PhPh3 prepared with 1,3,5-triphenylbenzene as the monomer and AlCl3 as the catalyst) by chemical transformations, such as nitration-reduction, sulfonation, and cationic exchange. The CO2 adsorption selectivity (CO2 /N2 and CO2 /H2 ) and isosteric heats of the microporous polymers increase markedly after modification, P-PhPh3 -NH2 and P-PhPh3 -SO3 Li afford higher CO2 uptake capacity than P-PhPh3 at pressures of less than 0.15 bar due to the enhanced interaction between CO2 and the -NH2 and -SO3 Li functional groups. Moreover, functionalized porous polymers could be stably used for CO2 capture. Surface modification is an efficient approach to tune the CO2 capture properties of porous polymers. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  16. Structure-activity relationship of Cr/Ti-PILC catalysts using a pre-modification method for NO oxidation and their surface species study.

    Science.gov (United States)

    Zhong, Lei; Yu, Yang; Cai, Wei; Geng, Xinxin; Zhong, Qin

    2015-06-14

    The performances of Cr/Ti-PILC catalysts, which were prepared by the pre-modification method, are studied for the selective catalytic oxidation of NO. The aim of this paper is to elucidate the detailed relationship between physical nanoparticle structure and chemical properties. The maximum NO conversion over the Cr-HP(3)/TP catalyst reached 71.4% at 280 °C. The catalysts were characterized by powder X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), temperature-programmed reduction of H2 (H2-TPR), temperature-programmed desorption (TPD) and diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS) techniques. The characterization results demonstrated that the enhanced catalytic activity was ascribed to several beneficial effects, which were caused by the pre-modification such as the inhibition of crystallite size, improvement of Cr species dispersion and increase of the amount of active sites. XPS and FTIR experiments indicated that two Cr(VI) species, oxidized state CrO3 and chromate species with the anionic form, were generated via pre-modification, which played different roles in the catalytic reaction. In addition, the TPR and TPD results suggest that the increased active sites (Cr(VI) species) were conducive for the preferential adsorption and activation of NO. Furthermore, DRIFTS results revealed that the intermediates, NO(+) and nitrates, interacted quickly to generate gaseous NO2.

  17. Insights into synergistic effect of chromium oxides and ceria supported on Ti-PILC for NO oxidation and their surface species study

    Science.gov (United States)

    Zhong, Lei; Cai, Wei; Yu, Yang; Zhong, Qin

    2015-01-01

    The insights of synergistic effect between chromium oxides and ceria supported on Ti-PILC were studied for NO oxidation. The aim of this study was to investigate the role of chromium oxides and ceria and their synergistic effect in textural properties, redox performance and surface species over the Cr1-xCex/TP catalysts. These catalysts were investigated in detail by means of Brunauer-Emmertt-Teller (BET) surface area analysis, X-ray diffraction (XRD), transmission electron microscope (TEM), temperature-programmed reduction of H2 (H2-TPR), temperature-programmed desorption (NO-TPD, O2-TPD), photoluminescence spectra (PL), X-ray photoelectron spectroscopy (XPS) and in situ diffuse reflectance infrared Fourier transform spectroscopy (in situ DRIFTS). It has been found that CrOx were beneficial to adsorb and activate NO to form NO+ and then generate nitrates while ceria were inclined to activate O2 via oxygen vacancies to produce nitrates. Besides, the results of in situ DRIFTS further demonstrated that surface species were associated with not only reaction atmosphere but also reaction temperature. Hence, a possible reaction model was tentatively proposed.

  18. Efficient fixation of CO2 by a zinc-coordinated conjugated microporous polymer.

    Science.gov (United States)

    Xie, Yong; Wang, Ting-Ting; Yang, Rui-Xia; Huang, Nian-Yu; Zou, Kun; Deng, Wei-Qiao

    2014-08-01

    Zinc-coordinated conjugated microporous polymers (Zn-CMPs), prepared by linking salen zinc and 1,3,5-triethynylbenzene, exhibit extraordinary activities (turnover frequencies of up to 11600 h(-1) ), broad substrate scope, and group tolerance for the synthesis of functional organic carbonates by coupling epoxides with CO2 at 120 °C and 3.0 MPa without the use of additional solvents. The catalytic activity of Zn-CMP is comparable to those of homogeneous catalysts and superior to those of other heterogeneous catalysts. This catalyst could be reused more than ten times without a significant decrease in performance.

  19. Synthesis of new hybrid sorbent by grafting 2,6-diacetyl pyridine onto microporous β-zeolite and its application in solid phase extraction of heavy metals from environmental samples

    Indian Academy of Sciences (India)

    HARINATH YAPATI; SREENU BHOGINENI; SURESH CHIRUMAMILLA; K SESHAIAH

    2016-05-01

    The aim of this study was synthesis of a new hybrid material and its application in solid phaseextraction of metal ions from environmental samples. The hybrid material was synthesized by grafting3-aminopropyl trimethoxy silane onto Β-zeolite and functionalizing with 2,6-diacetyl pyridine in a stepwise covalentprocess. This hybrid material was characterized by FT-IR and XRD studies. The hybrid material was usedas sorbent in solid phase extraction of Pb(II), Ni(II), Cu(II) and Cd(II). The method is based on the collectionof metal ions onto 2,6-DAP-PA-Β-zeolite and the sorbed metal ions were eluted with 10mL of 1M $HNO_{3}.The influences of analytical parameters such as pH of the sample solution, volume of sample, type and volumeof eluent, flow rate of the sample and eluent that govern the efficiency and throughput of the method wereevaluated. The influence effects of matrix ions (common ions other than the analyte that are present in the sample)on the retentions of the metal ions were also examined. The maximum adsorption capacity values for themetal ions onto 2,6-DAP-PA-Β-zeolite, as calculated from the Langmuir model, were 112.7, 94.2, 105, and102.8mg $g^{-1}$ respectively. The relative standard deviation under optimum conditions was lower than 3.10%.The limits of detection were 0.035 for Pb(II), 0.076 for Ni(II), 0.083 for Cu(II) and 0.059 mg $L^{-1}$ for Cd(II),respectively. The accuracy of the method was estimated by analyzing reference standard materials. The resultsindicate that the method is efficient for the solid phase extraction of trace levels of Pb(II), Ni(II), Cu(II) andCd(II) from environmental samples.

  20. Microporous material from kanemite for drug inclusion and release.

    Science.gov (United States)

    Ambrogi, V; Chiappini, I; Fardella, G; Grandolini, G; Marmottini, F; Perioli, L

    2001-01-01

    A microporous material obtained from kanemite, a layered polysilicate, was studied in order to investigate its feasibility of including drugs and then releasing them. Diphenydramine hydrochloride was chosen as a model drug. The preparation of the microporous material and its loading with the drug are described. As kanemite is able to intercalate anions between its layers, the intercalation compound of diphenydramine and kanemite was also prepared. Both the drug-loaded microporous material and the intercalation compound were submitted to dissolution tests at pH 7.5. The drug release profiles from these two different materials and from a physical mixture were compared.

  1. Insights into synergistic effect of chromium oxides and ceria supported on Ti-PILC for NO oxidation and their surface species study

    Energy Technology Data Exchange (ETDEWEB)

    Zhong, Lei [School of Environmental and Biological Engineering, Nanjing University of Science and Technology, Nanjing 210094 (China); Nanjing AIREP Environmental Protection Technology Co., Ltd., Nanjing, Jiangsu 210091 (China); Cai, Wei; Yu, Yang [School of Chemical Engineering, Nanjing University of Science and Technology, Nanjing 210094 (China); Nanjing AIREP Environmental Protection Technology Co., Ltd., Nanjing, Jiangsu 210091 (China); Zhong, Qin, E-mail: zq304@mail.njust.edu.cn [School of Environmental and Biological Engineering, Nanjing University of Science and Technology, Nanjing 210094 (China); School of Chemical Engineering, Nanjing University of Science and Technology, Nanjing 210094 (China); Nanjing AIREP Environmental Protection Technology Co., Ltd., Nanjing, Jiangsu 210091 (China)

    2015-01-15

    Graphical abstract: - Highlights: • Synergistic effect between CrO{sub x} and ceria supported on TP were studied for NO oxidation. • TPD results indicated NO and O{sub 2} were activated by CrO{sub x} and ceria, respectively. • H{sub 2}-TPR analysis suggested that CrO{sub x} undertook the main function in catalysis. • The nature and stability of surface-bound species were investigated by in situ DRIFTS. - Abstract: The insights of synergistic effect between chromium oxides and ceria supported on Ti-PILC were studied for NO oxidation. The aim of this study was to investigate the role of chromium oxides and ceria and their synergistic effect in textural properties, redox performance and surface species over the Cr{sub 1−x}Ce{sub x}/TP catalysts. These catalysts were investigated in detail by means of Brunauer–Emmertt–Teller (BET) surface area analysis, X-ray diffraction (XRD), transmission electron microscope (TEM), temperature-programmed reduction of H{sub 2} (H{sub 2}-TPR), temperature-programmed desorption (NO-TPD, O{sub 2}-TPD), photoluminescence spectra (PL), X-ray photoelectron spectroscopy (XPS) and in situ diffuse reflectance infrared Fourier transform spectroscopy (in situ DRIFTS). It has been found that CrO{sub x} were beneficial to adsorb and activate NO to form NO{sup +} and then generate nitrates while ceria were inclined to activate O{sub 2} via oxygen vacancies to produce nitrates. Besides, the results of in situ DRIFTS further demonstrated that surface species were associated with not only reaction atmosphere but also reaction temperature. Hence, a possible reaction model was tentatively proposed.

  2. Attractive forces in microporous carbon electrodes for capacitive deionization

    CERN Document Server

    Biesheuvel, P M; Levi, M; Bazant, M Z

    2013-01-01

    The recently developed modified Donnan (mD) model provides a simple and useful description of the electrical double layer in microporous carbon electrodes, suitable for incorporation in porous electrode theory. By postulating an attractive excess chemical potential for each ion in the micropores that is inversely proportional to the total ion concentration, we show that experimental data for capacitive deionization (CDI) can be accurately predicted over a wide range of applied voltages and salt concentrations. Since the ion spacing and Bjerrum length are each comparable to the micropore size (few nm), we postulate that the attraction results from fluctuating bare Coulomb interactions between individual ions and the metallic pore surfaces (image forces) that are not captured by meanfield theories, such as the Poisson-Boltzmann-Stern model or its mathematical limit for overlapping double layers, the Donnan model. Using reasonable estimates of the micropore permittivity and mean size (and no other fitting parame...

  3. Structure and Capacitance of Electrical Double Layers inside Micropores

    Science.gov (United States)

    Feng, Guang; Qiao, Rui; Huang, Jingsong; Sumpter, Bobby G.; Meunier, Vincent

    2010-03-01

    Recent experiments indicate that the specific capacitance of micropores (diameter less than 2nm) increases anomalously as the pore size decreases^[1]. To understand the physical origin of this discovery, we performed a series of molecular dynamics simulations to study the electrical double layers (EDLs) in micropores with different shapes (tube vs slit) and pore sizes (0.668nm - 3.342nm). Several different aqueous electrolytes (K^+, Na^+, Cl^-, and F^- in water) were used in these micropores. We quantified the structure of EDLs inside the pores, and computed the capacitance of EDLs. The scaling of capacitance shows a qualitative agreement with the experimental observations. We attribute the anomalous enhancement of capacitance in micropores to the short-range ionelectrode and ionsolvent interactions.[1] J. Chmiola, G. Yushin, Y. Gogotsi, C. Portet, P. Simon, and P.L. Taberna, Science 2006, 313, 1760.

  4. Nitrogen-doped micropore-dominant carbon derived from waste pine cone as a promising metal-free electrocatalyst for aqueous zinc/air batteries

    Science.gov (United States)

    Lei, Xiaoke; Wang, Mengran; Lai, Yanqing; Hu, Langtao; Wang, Hao; Fang, Zhao; Li, Jie; Fang, Jing

    2017-10-01

    The exploitation for highly effective and low-cost metal-free catalysts with facile and environmental friendly method for oxygen reduction reaction is still a great challenge. To find an effective method for catalyst synthesis, in this manuscript, waste biomass pine cone is employed as raw material and nitrogen-doped micropore-dominant carbon material with excellent ORR catalytic activity is successfully synthesized. The as-prepared N-doped micropore-dominant carbon possesses a high surface area of 1556 m2 g-1. In addition, this carbon electrocatalyst loaded electrode exhibits a high discharge voltage 1.07 V at the current density of 50 mA cm-2, which can be ascribed to the rich micropores and high content of pyridinic N of the prepared carbon, indicative of great potential in the application of zinc/air batteries.

  5. Diclofenac delays micropore closure following microneedle treatment in human subjects.

    Science.gov (United States)

    Brogden, Nicole K; Milewski, Mikolaj; Ghosh, Priyanka; Hardi, Lucia; Crofford, Leslie J; Stinchcomb, Audra L

    2012-10-28

    Drugs absorbed poorly through the skin are commonly delivered via injection with a hypodermic needle, which is painful and increases the risk of transmitting infectious diseases. Microneedles (MNs) selectively and painlessly permeabilize the outermost skin layer, allowing otherwise skin-impermeable drugs to cross the skin through micron-sized pores and reach therapeutic concentrations. However, rapid healing of the micropores prevents further drug delivery, blunting the clinical utility of this unique transdermal technique. We present the first human study demonstrating that micropore lifetime can be extended following MN treatment. Subjects received one-time MN treatment and daily topical application of diclofenac sodium. Micropore closure was measured with impedance spectroscopy, and area under the admittance-time curve (AUC) was calculated. AUC was significantly higher at MN+diclofenac sodium sites vs. placebo, suggesting slower rates of micropore healing. Colorimetry measurements confirmed the absence of local erythema and irritation. This mechanistic human proof-of-concept study demonstrates that micropore lifetime can be prolonged with simple topical administration of a non-specific cyclooxygenase inhibitor, suggesting the involvement of subclinical inflammation in micropore healing. These results will allow for longer patch wear time with MN-enhanced delivery, thus increasing patient compliance and expanding the transdermal field to a wider variety of clinical conditions. Copyright © 2012 Elsevier B.V. All rights reserved.

  6. 稀土元素对Mn/TiO_2-PILC低温SCR性能影响研究%The Modified Effects of Rare Earth to Mn/TiO_2-PILC for Low Temperature SCR

    Institute of Scientific and Technical Information of China (English)

    姚燕; 马宏卿; 沈伯雄; 唐雪娇

    2012-01-01

    8%Mn/Titania-pillared clays(8%Mn/TiO_2-PILC) and rare earth modified catalysts 8%Mn-2%R/TiO_2-PILC were prepared by the impregnation method for the low-temperature selective catalytic reduction(SCR) of NO with NH_3,their resistance to water vapor and sulfur dioxide.It was found that the addition of rare earth would change the phy-chemstry properties of 8%Mn/TiO_2-PILC and inhence inprove the NO conversion.The addition of rare earth,especially Ce,suppresses the deactivation to a degree although the SO_2 resistances of the catalysts are weak.%通过浸渍法制备了8%Mn/TiO_2-PILC以及稀土元素R(Ce,La)改性的8%Mn-2%R/TiO_2-PILC催化剂,考察了所制备催化剂的低温NH_3-SCR活性和抗水抗硫特性。结果发现,Ce的添加改变了催化剂的物相以及氧化还原特性,从而改变了催化剂的NO去除活性;稀土元素的添加可以减缓催化剂的失活速率,但是抗水抗硫特性仍然不理想。

  7. Triazine containing N-rich microporous organic polymers for CO2 capture and unprecedented CO2/N2 selectivity

    Science.gov (United States)

    Bhunia, Subhajit; Bhanja, Piyali; Das, Sabuj Kanti; Sen, Tapas; Bhaumik, Asim

    2017-03-01

    Targeted synthesis of microporous adsorbents for CO2 capture and storage is very challenging in the context of remediation from green house gases. Herein we report two novel N-rich microporous networks SB-TRZ-CRZ and SB-TRZ-TPA by extensive incorporation of triazine containing tripodal moiety in the porous polymer framework. These materials showed excellent CO2 storage capacities: SB-TRZ-CRZ displayed the CO2 uptake capacity of 25.5 wt% upto 1 bar at 273 K and SB-TRZ-TPA gave that of 16 wt% under identical conditions. The substantial dipole quadruple interaction between network (polar triazine) and CO2 boosts the selectivity for CO2/N2. SB-TRZ-CRZ has this CO2/N2 selectivity ratio of 377, whereas for SB-TRZ-TPA it was 97. Compared to other porous polymers, these materials are very cost effective, scalable and very promising material for clean energy application and environmental issues.

  8. Filtration performance of microporous ceramic supports.

    Science.gov (United States)

    Belouatek, Aissa; Ouagued, Abdellah; Belhakem, Mustapha; Addou, Ahmed

    2008-04-24

    The use of inorganic membranes in pollution treatment is actually limited by the cost of such membranes. Advantages of inorganic membranes are their chemical, thermal and pH properties. The purpose of this work was the development of microporous ceramic materials based on clay for liquid waste processing. The supports or ceramic filters having various compositions were prepared and thermally treated at 1100 degrees C. The results show that, at the temperature studied, porosity varied according to the support composition from 12% for the double-layered (ceramic) support to 47% for the activated carbon- filled support with a mean pore diameter between 0.8 and 1.3 microm, respectively. Volumes of 5 l of distilled water were filtered tangentially for 3 h under an applied pressure of 3.5 and 5.5 bar. The retention of tubular supports prepared was tested with molecules of varying size (Evans blue, NaCl and Sacharose). The study of the liquid filtration and flow through these supports showed that the retention rate depends on support composition and pore diameter, and solute molecular weight. The S1 support (mixture of barbotine and 1% (w/w) activated carbon) gave a flux for distilled water of 68 L/m2 h while the double-layered support resulted in a flux of 8 L/m2 h for the same solution at the pressure of 3.5 bar. At a pressure of 5.5 bar an increase in the distilled water flux through the various supports was observed. It was significant for the S1 support (230 L/m h).

  9. Molecular Simulation of Adsorption in Microporous Materials

    Directory of Open Access Journals (Sweden)

    Yiannourakou M.

    2013-11-01

    Full Text Available The development of industrial software, the decreasing cost of computing time, and the availability of well-tested forcefields make molecular simulation increasingly attractive for chemical engineers. We present here several applications of Monte-Carlo simulation techniques, applied to the adsorption of fluids in microporous solids such as zeolites and model carbons (pores < 2 nm. Adsorption was computed in the Grand Canonical ensemble with the MedeA®-GIBBS software, using energy grids to decrease computing time. MedeA®-GIBBS has been used for simulations in the NVT or NPT ensembles to obtain the density and fugacities of fluid phases. Simulation results are compared with experimental pure component isotherms in zeolites (hydrocarbon gases, water, alkanes, aromatics, ethanethiol, etc., and mixtures (methane-ethane, n-hexane-benzene, over a large range of temperatures. Hexane/benzene selectivity inversions between silicalite and Na-faujasites are well predicted with published forcefields, providing an insight on the underlying mechanisms. Also, the adsorption isotherms in Na-faujasites for light gases or ethane-thiol are well described. Regarding organic adsorbents, models of mature kerogen or coal were built in agreement with known chemistry of these systems. Obtaining realistic kerogen densities with the simple relaxation approach considered here is encouraging for the investigation of other organic systems. Computing excess sorption curves in qualitative agreement with those recently measured on dry samples of gas shale is also favorable. Although still preliminary, such applications illustrate the strength of molecular modeling in understanding complex systems in conditions where experiments are difficult.

  10. Fluvastatin as a micropore lifetime enhancer for sustained delivery across microneedle-treated skin.

    Science.gov (United States)

    Ghosh, Priyanka; Brogden, Nicole K; Stinchcomb, Audra L

    2014-02-01

    Microneedles (MNs), a physical skin permeation enhancement technique, facilitate drug delivery across the skin, thus enhancing the number of drugs that can be delivered transdermally in therapeutically relevant concentrations. The micropores created in the skin by MNs reseal because of normal healing processes of the skin, thus limiting the duration of the drug delivery window. Pore lifetime enhancement strategies can increase the effectiveness of MNs as a drug delivery mechanism by prolonging the delivery window. Fluvastatin (FLU), a HMGCoA reductase inhibitor, was used in this study to enhance the pore lifetime by inhibiting the synthesis of cholesterol, a major component of the stratum corneum lipids. The study showed that using FLU as a pretreatment it is possible to enhance the pore lifetime of MN-treated skin and thus allow for sustained drug delivery. The skin recovered within a 30-45-min time period following the removal of occlusion, and there was no significant irritation observed due to the treatment compared to the control sites. Thus, it can be concluded that localized skin treatment with FLU can be used to extend micropore lifetime and deliver drugs for up to 7 days across MN-treated skin.

  11. Capture and Reversible Storage of Volatile Iodine by Novel Conjugated Microporous Polymers Containing Thiophene Units.

    Science.gov (United States)

    Qian, Xin; Zhu, Zhao-Qi; Sun, Han-Xue; Ren, Feng; Mu, Peng; Liang, Weidong; Chen, Lihua; Li, An

    2016-08-17

    Conjugated microporous polymers having thiophene building blocks (SCMPs), which originated from ethynylbenzene monomers with 2,3,5-tribromothiophene, were designedly synthesized through Pd(0)/CuI catalyzed Sonogashira-Hagihara cross-coupling polymerization. The morphologies, structure and physicochemical properties of the as-synthesized products were characterized through scanning electron microscope (SEM), thermogravimeter analysis (TGA), (13)C CP/MAS solid state NMR and Fourier transform infrared spectroscope (FTIR) spectra. Nitrogen sorption-desorption analysis shows that the as-synthesized SCMPs possesses a high specific surface area of 855 m(2) g(-1). Because of their abundant porosity, π-conjugated network structure, as well as electron-rich thiophene building units, the SCMPs show better adsorption ability for iodine and a high uptake value of 222 wt % was obtained, which can compete with those nanoporous materials such as silver-containing zeolite, metal-organic frameworks (MOFs) and conjugated microporous polymers (CMPs), etc. Our study might provide a new possibility for the design and synthesis of functional CMPs containing electron-rich building units for effective capture and reversible storage of volatile iodine to address environmental issues.

  12. Temperature-regulated guest admission and release in microporous materials

    Science.gov (United States)

    Li, Gang (Kevin); Shang, Jin; Gu, Qinfen; Awati, Rohan V.; Jensen, Nathan; Grant, Andrew; Zhang, Xueying; Sholl, David S.; Liu, Jefferson Z.; Webley, Paul A.; May, Eric F.

    2017-06-01

    While it has long been known that some highly adsorbing microporous materials suddenly become inaccessible to guest molecules below certain temperatures, previous attempts to explain this phenomenon have failed. Here we show that this anomalous sorption behaviour is a temperature-regulated guest admission process, where the pore-keeping group's thermal fluctuations are influenced by interactions with guest molecules. A physical model is presented to explain the atomic-level chemistry and structure of these thermally regulated micropores, which is crucial to systematic engineering of new functional materials such as tunable molecular sieves, gated membranes and controlled-release nanocontainers. The model was validated experimentally with H2, N2, Ar and CH4 on three classes of microporous materials: trapdoor zeolites, supramolecular host calixarenes and metal-organic frameworks. We demonstrate how temperature can be exploited to achieve appreciable hydrogen and methane storage in such materials without sustained pressure. These findings also open new avenues for gas sensing and isotope separation.

  13. Responsive Guest Encapsulation of Dynamic Conjugated Microporous Polymers.

    Science.gov (United States)

    Xu, Lai; Li, Youyong

    2016-06-30

    The host-guest complexes of conjugated microporous polymers encapsulating C60 and dye molecules have been investigated systematically. The orientation of guest molecules inside the cavities, have different terms: inside the open cavities of the polymer, or inside the cavities formed by packing different polymers. The host backbone shows responsive dynamic behavior in order to accommodate the size and shape of incoming guest molecule or guest aggregates. Simulations show that the host-guest binding of conjugated polymers is stronger than that of non-conjugated polymers. This detailed study could provide a clear picture for the host-guest interaction for dynamic conjugated microporous polymers. The mechanism obtained could guide designing new conjugated microporous polymers.

  14. Microporous adsorbents for CO2 capture – a case for microporous polymers?

    Directory of Open Access Journals (Sweden)

    Chao Xu

    2014-10-01

    Full Text Available Microporous polymers (MOPs belong to a relatively new class of polymers that could find applications in gas separation processes, both as adsorbents and as polymer membranes. These polymers are constructed from purely organic building blocks by covalent bonds. It is possible to synthesize them by a range of different reactions that are either catalyzed with or without metal centers. Recently, these polymers have been researched in detail as potential sorbents, or membrane materials for a separation of CO2 from flue gas. Both adsorption driven and membrane driven separation of CO2 from flue gas could offer more cost effective alternatives to the methods currently in use. Here, we review recent papers and present our view on the opportunities and challenges when it comes to the use of MOPs in carbon capture and storage (CCS.

  15. A large deformation poroplasticity theory for microporous polymeric materials

    Science.gov (United States)

    Anand, Lallit

    2017-01-01

    A coupled theory accounting for fluid diffusion and large deformations of elastic-viscoplastic microporous polymeric materials is presented. The theory is intended to represent the coupled deformation-diffusion response of a material which at a microscopic scale consists of a porous polymeric skeleton and a freely moving fluid in a fully connected pore space. Potential applications of the theory include modeling the response of polymer microfiltration membranes, as well as modeling the response of several hydrated biological tissues which are microporous polymeric materials containing a high concentration of liquids.

  16. Formation of titanium carbide coating with micro-porous structure

    Science.gov (United States)

    Luo, Yong; Ge, Shirong; Jin, Zhongmin; Fisher, John

    2010-03-01

    Micro-porous titanium carbide coating was successfully synthesized in a vacuum gas carburizing furnace by using a sequential diffusion technology. The composition and structure of the as-synthesized TiC were examined by X-ray diffraction, X-ray photoelectron spectroscopy (XPS) and glow discharge mass spectrometry (GDMS), and scanning electron microscopy (SEM). All of the XRD, XPS and GDMS analysis results indicate that carbon atoms effectively diffused into the titanium alloys and formed a uniform acicular TiC coating with micro-porous structure.

  17. Preparation of PILCs With Different Pillar Materials Loading Mn-Ce and De-NO Activity%不同柱撑物负载Mn-Ce层柱黏土制备及脱硝性能

    Institute of Scientific and Technical Information of China (English)

    沈伯雄; 孙喜; 杨晓燕

    2013-01-01

    为了考察不同柱撑物对层柱黏土为载体的低温SCR催化剂性能的影响,分别选择钛氧化物、锆氧化物和铁氧化物为柱撑物质,得到不同的层柱黏土.采用浸渍法分别负载锰铈后得到相应催化剂.分别运用BET、XRD、H2-TPR、NH3-TPD对催化剂进行表征分析.并在固定床反应器上测试其低温SCR催化活性.结果表明3种层柱黏土制得催化剂的比表面积、孔体积、表面还原性和酸性与未进行柱撑的黏土制得的催化剂相比均有明显提高.而Mn-Ce/Zr-PILC的SCR脱硝活性最佳,在240℃时,脱硝活性达到90%.实验结果表明,催化剂的活性受比表面积、表面酸性和还原性等因素的共同制约,其中,催化剂表面的酸性起到的作用更加明显.%To investigate the effect of different pillar materials on low-temperature de-NO activity of PILCs, the study attempted to pillar the clay with three different kinds of metal oxides (titanium oxides, zirconium oxides, iron oxides) to obtain different kinds of PILCs, then load them with manganese and cerium oxides using the method of impregnation. BET, XRD, H2-TPR and NH3-TPD characterization methods were used to study the property-activity relationship of the catalysts, and evaluate the low temperature SCR activity of the catalysis. The results indicate that the specific surface area, pore volume, deoxidization property and surface acidity of the catalysts derived from PILCs are all improved compared with those derived from the clays without pillared. Mn-Ce/Zr-PILC is proved to be the most efficient in the SCR of de-NO with NH3, its de-NO activity is as high as 90% at 240 °C. According to the test results, the de-NO activities of the catalysts are affected by the combination of the specific surface area, surface acidity and reduction property, among them, the surface acidity is the most important.

  18. Intrinsically microporous polyesters from betulin - toward renewable materials for gas separation made from birch bark.

    Science.gov (United States)

    Jeromenok, Jekaterina; Böhlmann, Winfried; Antonietti, Markus; Weber, Jens

    2011-11-15

    Betulin, an abundant triterpene, can be extracted from birch bark and can be used as a renewable monomer in the synthesis of microporous polyesters. Cross-linked networks and hyperbranched polymers are accessible by an A(2) + B(3) reaction, with betulin being the A(2) monomer and B(3) being a trifunctional acid chloride. Reaction of betulin with a diacid dichloride results in linear, soluble polyesters. The present communication proves that the polyreaction follows the classic schemes of polycondensation reactions. The resulting polymers are analyzed with regard to their micro-porosity by gas sorption, NMR spectroscopy, and X-ray scattering methods. The polymers feature intrinsic microporosity, having ultrasmall pores, which makes them candidates for gas separation membranes, e.g., for the separation of CO(2) from N(2) .

  19. Separating mixtures by exploiting molecular packing effects in microporous materials

    NARCIS (Netherlands)

    Krishna, R.

    2014-01-01

    We examine mixt. sepns. with microporous adsorbents such as zeolites, metal-​org. frameworks (MOFs) and zeolitic imidazolate frameworks (ZIFs)​, operating under conditions close to pore satn. Pore satn. is realized, for example, when sepg. bulk liq. phase mixts. of polar compds. such as water, alcs.

  20. Hydrothermal stability of microporous silica and niobia-silica membranes

    NARCIS (Netherlands)

    Boffa, V.; Blank, David H.A.; ten Elshof, Johan E.

    2008-01-01

    The hydrothermal stability of microporous niobia–silica membranes was investigated and compared with silica membranes. The membranes were exposed to hydrothermal conditions at 150 and 200 °C for 70 h. The change of pore structure before and after exposure to steam was probed by single-gas permeation

  1. Tunable Reactive Wetting of Sn on Microporous Cu Layer

    Institute of Scientific and Technical Information of China (English)

    Qingquan Lai; Lei Zhang; Cai Chen; J.K. Shang

    2012-01-01

    Wetting of microporous Cu layer by liquid Sn resulted in contact angles from 0 to 33 deg., tunable by varying wetting temperature and porous microstructure. The wetting was dominated by the interracial metallurgical reaction, which can lead to pore closure phenomenon, as the liquid infiltration facilitating the wetting process.

  2. Fabrication and characterization of non-linear parabolic microporous membranes.

    Science.gov (United States)

    Rajasekaran, Pradeep Ramiah; Sharifi, Payam; Wolff, Justin; Kohli, Punit

    2015-01-01

    Large scale fabrication of non-linear microporous membranes is of technological importance in many applications ranging from separation to microfluidics. However, their fabrication using traditional techniques is limited in scope. We report on fabrication and characterization of non-linear parabolic micropores (PMS) in polymer membranes by utilizing flow properties of fluids. The shape of the fabricated PMS corroborated well with simplified Navier-Stokes equation describing parabolic relationship of the form L - t(1/2). Here, L is a measure of the diameter of the fabricated micropores during flow time (t). The surface of PMS is smooth due to fluid surface tension at fluid-air interface. We demonstrate fabrication of PMS using curable polydimethylsiloxane (PDMS). The parabolic shape of micropores was a result of interplay between horizontal and vertical fluid movements due to capillary, viscoelastic, and gravitational forces. We also demonstrate fabrication of asymmetric "off-centered PMS" and an array of PMS membranes using this simple fabrication technique. PMS containing membranes with nanoscale dimensions are also possible by controlling the experimental conditions. The present method provides a simple, easy to adopt, and energy efficient way for fabricating non-linear parabolic shape pores at microscale. The prepared parabolic membranes may find applications in many areas including separation, parabolic optics, micro-nozzles / -valves / -pumps, and microfluidic and microelectronic delivery systems.

  3. The structure and reactivity of microporous and oxide catalysts

    Science.gov (United States)

    Lewis, Dewi Wyn

    Microporous and metal oxide heterogeneous catalysts have been investigated using a range of computational techniques. The results of studies of the factors influencing the synthesis, structure and activity of these materials are presented here. A study of the interactions between zeolitic frameworks and organic templates has demonstrated how the efficacy of a template can be determined and an energetic rationalisation of templating ability is demonstrated. The location of templates within frameworks are found to be accurately determined and subtle differences in framework structure are rationalised in terms of the template used. We have been able to determine the templating action of bis-quaternary ammonium cations in the aluminophosphate DAF-1, results which have allowed the synthesis of new compositions of this material. We have further used these results to design a new template which will not form DAF-1 and which we propose as a termplate which may favour a new material. We demonstrate that such computer-aided design of templates can be used to assist the search for new materials. We have successfully modelled the local geometry of the iron and Bronsted acid site in Fe-ZSM5 using atomistic simulation techniques. A broad range of cation T sites are predicted to be occupied by iron, with T19 and T18 being the most energetically favourable. The accuracy of the calculations is demonstrated by the reproduction of the experimental EXAFS. We further propose improved models which better describe the local environment and which improve on the fit to experimental data. The effect of the inclusion of iron on the physical properties and catalytic activity is determined and compared to similar results for A1-ZSM5. The subtle differences between these two materials is reproduced. Iron incorporation modifies the pore dimensions, reducing the maximum pore dimension by 0.4A, an effect which can be correlated to experimental data on the selectivity of the material. Calculations

  4. Molecular imprinting of bulk, microporous silica

    Science.gov (United States)

    Katz, Alexander; Davis, Mark E.

    2000-01-01

    Molecular imprinting aims to create solid materials containing chemical functionalities that are spatially organized by covalent or non-covalent interactions with imprint (or template) molecules during the synthesis process. Subsequent removal of the imprint molecules leaves behind designed sites for the recognition of small molecules, making the material ideally suited for applications such as separations, chemical sensing and catalysis. Until now, the molecular imprinting of bulk polymers and polymer and silica surfaces has been reported, but the extension of these methods to a wider range of materials remains problematic. For example, the formation of substrate-specific cavities within bulk silica, while conceptually straightforward, has been difficult to accomplish experimentally. Here we describe the imprinting of bulk amorphous silicas with single aromatic rings carrying up to three 3-aminopropyltriethoxysilane side groups; this generates and occupies microporosity and attaches functional organic groups to the pore walls in a controlled fashion. The triethoxysilane part of the molecules' side groups is incorporated into the silica framework during sol-gel synthesis, and subsequent removal of the aromatic core creates a cavity with spatially organized aminopropyl groups covalently anchored to the pore walls. We find that the imprinted silicas act as shape-selective base catalysts. Our strategy can be extended to imprint other functional groups, which should give access to a wide range of functionalized materials.

  5. Yeast-based microporous carbon materials for carbon dioxide capture.

    Science.gov (United States)

    Shen, Wenzhong; He, Yue; Zhang, Shouchun; Li, Junfen; Fan, Weibin

    2012-07-01

    A hierarchical microporous carbon material with a Brunauer-Emmett-Teller surface area of 1348 m(2) g(-1) and a pore volume of 0.67 cm(3) g(-1) was prepared from yeast through chemical activation with potassium hydroxide. This type of material contains large numbers of nitrogen-containing groups (nitrogen content >5.3 wt%), and, consequently, basic sites. As a result, this material shows a faster adsorption rate and a higher adsorption capacity of CO(2) than the material obtained by directly carbonizing yeast under the same conditions. The difference is more pronounced in the presence of N(2) or H(2)O, showing that chemical activation of discarded yeast with potassium hydroxide could afford high-performance microporous carbon materials for the capture of CO(2).

  6. Microporous polymer electrolyte based on PVDF-PEO

    Institute of Scientific and Technical Information of China (English)

    LI Jian; XI Jingyu; SONG Qing; TANG Xiaozhen

    2005-01-01

    @@ Since Wright et al.[1] found that the complex of PEO/alkali metals salt had the ability of ionic conductivity in 1973, in-depth studies have been carried out about various polymer electrolytes, which were applied to replacing the liquid electrolytes in lithium ion battery[2,3]. At present, polymer electrolytes mainly include three kinds: dry polymer electrolytes, gel polymer electrolytes and microporous polymer electrolytes.

  7. Microporous calcium phosphate ceramics driving osteogenesis through surface architecture.

    Science.gov (United States)

    Zhang, Jingwei; Barbieri, Davide; ten Hoopen, Hetty; de Bruijn, Joost D; van Blitterswijk, Clemens A; Yuan, Huipin

    2015-03-01

    The presence of micropores in calcium phosphate (CaP) ceramics has shown its important role in initiating inductive bone formation in ectopic sites. To investigate how microporous CaP ceramics trigger osteoinduction, we optimized two biphasic CaP ceramics (i.e., BCP-R and BCP-S) to have the same chemical composition, equivalent surface area per volume, comparable protein adsorption, similar ion (i.e., calcium and phosphate) exchange and the same surface mineralization potential, but different surface architecture. In particular, BCP-R had a surface roughness (Ra) of 325.4 ± 58.9 nm while for BCP-S it was 231.6 ± 35.7 nm. Ceramic blocks with crossing or noncrossing channels of 250, 500, 1000, and 2000 µm were implanted in paraspinal muscle of dogs for 12 weeks. The percentage of bone volume in the channels was not affected by the type of pores (i.e., crossing vs. closed) or their size, but it was greatly influenced by the ceramic type (i.e., BCP-R vs. BCP-S). Significantly, more bone was formed in the channels of BCP-R than in those of BCP-S. Since the two CaP ceramics differed only in their surface architecture, the results hereby demonstrate that microporous CaP ceramics may induce ectopic osteogenesis through surface architecture.

  8. Fabrication of interconnected microporous biomaterials with high hydroxyapatite nanoparticle loading

    Energy Technology Data Exchange (ETDEWEB)

    Zhang Wei; Yao Donggang [School of Polymer Textile and Fiber Engineering, Georgia Institute of Technology, Atlanta, GA (United States); Zhang Qingwei; Lelkes, Peter I [School of Biomedical Engineering, Science, and Health Systems, Drexel University, Philadelphia, PA 19104 (United States); Zhou, Jack G, E-mail: yao@gatech.ed [Department of Mechanical Engineering and Mechanics, Drexel University, Philadelphia, PA 19104 (United States)

    2010-09-15

    Hydroxyapatite (HA) is known to promote osteogenicity and enhance the mechanical properties of biopolymers. However, incorporating a large amount of HA into a porous biopolymer still remains a challenge. In the present work, a new method was developed to produce interconnected microporous poly(glycolic-co-lactic acid) (PLGA) with high HA nanoparticle loading. First, a ternary blend comprising PLGA/PS (polystyrene)/HA (40/40/20 wt%) was prepared by melt blending under conditions for formation of a co-continuous phase structure. Next, a dynamic annealing stage under small-strain oscillation was applied to the blend to facilitate nanoparticle redistribution. Finally, the PS phase was sacrificially extracted, leaving a porous matrix. The results from different characterizations suggested that the applied small-strain oscillation substantially accelerated the migration of HA nanoparticles during annealing from the PS phase to the PLGA phase; nearly all HA particles were uniformly presented in the PLGA phase after a short period of annealing. After dissolution of the PS phase, a PLGA material with interconnected microporous structure was successfully produced, with a high HA loading above 30 wt%. The mechanisms beneath the experimental observations, particularly on the enhanced particle migration process, were discussed, and strategies for producing highly particle loaded biopolymers with interconnected microporous structures were proposed.

  9. Development and evaluation of microporous osmotic tablets of diltiazem hydrochloride.

    Science.gov (United States)

    Bathool, Afifa; Gowda, D V; Khan, Mohammed S; Ahmed, Ayaz; Vasudha, S L; Rohitash, K

    2012-04-01

    Microporous osmotic tablet of diltiazem hydrochloride was developed for colon targeting. These prepared microporous osmotic pump tablet did not require laser drilling to deliver the drug to the specific site of action. The tablets were prepared by wet granulation method. The prepared tablets were coated with microporous semipermeable membrane and enteric polymer using conventional pan coating process. The incorporation of sodium lauryl sulfate (SLS), a leachable pore-forming agent, could form in situ delivery pores while coming in contact with gastrointestinal medium. The effect of formulation variables was studied by changing the amounts of sodium alginate and NaCMC in the tablet core, osmogen, and that of pore-forming agent (SLS) used in the semipermeable coating. As the amount of hydrophilic polymers increased, drug release rate prolonged. It was found that drug release was increased as the concentration of osmogen and pore-former was increased. Fourier transform infrared spectroscopy and Differential scanning calorimetry results showed that there was no interaction between drug and polymers. Scanning electron microscopic studies showed the formation of pores after predetermined time of coming in contact with dissolution medium. The formation of pores was dependent on the amount of pore former used in the semipermeable membrane. in vitro results showed acid-resistant, timed release at an almost zero order up to 24 hours. The developed osmotic tablets could be effectively used for prolonged delivery of Diltiazem HCl.

  10. Development and evaluation of microporous osmotic tablets of diltiazem hydrochloride

    Directory of Open Access Journals (Sweden)

    Afifa Bathool

    2012-01-01

    Full Text Available Microporous osmotic tablet of diltiazem hydrochloride was developed for colon targeting. These prepared microporous osmotic pump tablet did not require laser drilling to deliver the drug to the specific site of action. The tablets were prepared by wet granulation method. The prepared tablets were coated with microporous semipermeable membrane and enteric polymer using conventional pan coating process. The incorporation of sodium lauryl sulfate (SLS, a leachable pore-forming agent, could form in situ delivery pores while coming in contact with gastrointestinal medium. The effect of formulation variables was studied by changing the amounts of sodium alginate and NaCMC in the tablet core, osmogen, and that of pore-forming agent (SLS used in the semipermeable coating. As the amount of hydrophilic polymers increased, drug release rate prolonged. It was found that drug release was increased as the concentration of osmogen and pore-former was increased. Fourier transform infrared spectroscopy and Differential scanning calorimetry results showed that there was no interaction between drug and polymers. Scanning electron microscopic studies showed the formation of pores after predetermined time of coming in contact with dissolution medium. The formation of pores was dependent on the amount of pore former used in the semipermeable membrane. in vitro results showed acid-resistant, timed release at an almost zero order up to 24 hours. The developed osmotic tablets could be effectively used for prolonged delivery of Diltiazem HCl.

  11. Microporous bilayer osmotic tablet for colon-specific delivery.

    Science.gov (United States)

    Chaudhary, Anil; Tiwari, Neha; Jain, Vikas; Singh, Ranjit

    2011-05-01

    Microporous bilayer osmotic tablet bearing dicyclomine hydrochloride and diclofenac potassium was developed using a new oral drug delivery system for colon targeting. The tablets were coated with microporous semipermeable membrane and enteric polymer using conventional pan-coating process. The developed microporous bilayer osmotic pump tablet (OPT) did not require laser drilling to form the drug delivery orifice. The colon-specific biodegradation of pectin could form in situ delivery pores for drug release. The effect of formulation variables like inclusion of osmogen, amount of HPMC and NaCMC in core, amount of pore former in semipermeable membrane was studied. Scanning electron microscopic photographs showed formation of in situ delivery pores after predetermined time of coming in contact with dissolution medium. The number of pores was dependent on the amount of the pore former in the semipermeable membrane. In vitro dissolution results indicated that system showed acid-resistant, timed release and was able to deliver drug at an approximate zero order up to 24h. The developed tablets could be effectively used for colon-specific drug delivery to treat IBS. Copyright © 2011 Elsevier B.V. All rights reserved.

  12. 基于含锌有机配位聚合物的微孔碳的合成及其电化学性能%Synthesis and Electrochemical Performance of Microporous Carbon Using a Zinc(Ⅱ)-Organic Coordination Polymer

    Institute of Scientific and Technical Information of China (English)

    钱佳晟; 刘明贤; 甘礼华; 吕耀康; 陈玲艳; 叶瑞杰; 陈龙武

    2013-01-01

    Microporous carbon was prepared using a novel procedure based on a zinc(Ⅱ)-organic coordination polymer.The polymer was prepared through the coordination interaction of zinc ions with tartaric acid,and then it was introduced into the open networks of resorcinol/formaldehyde (R/F) resol using hydrogen-bonding interactions.The R/F resol and zinc-organic coordination compound system copolymerized to produce an R/F and zinc-organic coordination copolymer.The copolymer was then heat-treated at 950 ℃C to decompose and evaporate zinc to fabricate microporous carbon materials.The carbon materials possessed relatively regular large micropores,with a specific surface area of up to 1260 m2· g-1 and a total pore volume of 0.63 cm3· g-1.The resultant microporous carbon materials were used as supercapacitor electrodes,exhibiting an equivalent series resistance of 0.46 Ω,and ideal capacitive behavior with a rectangular shape in cyclic voltammograms.Galvanostatic charge/discharge measurements of the carbon materials gave a specific capacitance of 196 F·g-1 at a current density of 1 A·g-1 and 137 F· g-1 at a large current density of 10 A· g-1.A high retention of 98% was measured for the long-term cycling stability (~1000 cycles) of the mesoporous carbon.Overall,the microporous carbon materials exhibited very good electrochemical performance.This study highlights the potential of well-designed microporous carbon materials as electrodes for diverse supercapacitor applications.%报道了一种基于含锌(Ⅱ)有机配位聚合物制备微孔碳的新方法.通过锌离子和酒石酸之间的配位作用获得含锌有机配位化合物,并通过氢键作用将其引入到间苯二酚/甲醛低聚物溶胶的开放网络结构中.使含锌有机配位化合物和酚醛低聚物溶胶体系发生共聚反应得到酚醛和含锌有机配位共聚物,在950℃C下热处理分解以及锌蒸气蒸发后制得微孔碳.微孔碳材料典型样品具有相对较大以及

  13. Phenol Solvothermal Synthesis of JBW-Type Zeolites

    Institute of Scientific and Technical Information of China (English)

    WEI Bo; WANG Ye; XIN Ming-hong; QIU Shi-lun

    2007-01-01

    Phenol was used as an aromatic and acidic solvent in solvothermal synthesis. JBW- type zeolites were successfully synthesized in a phenolic system. The as-synthesized microporous crystals were characterized by powder X-ray diffraction analysis and scanning electron microscopy techniques. The results indicate that phenol is a good organic solvent and has a huge potential of application in studying crystallization mechanism and synthesizing novel microporous materials.

  14. Interface physics in microporous media : LDRD final report.

    Energy Technology Data Exchange (ETDEWEB)

    Yaklin, Melissa A.; Knutson, Chad E.; Noble, David R.; Aragon, Alicia R.; Chen, Ken Shuang; Giordano, Nicholas J. (Purdue University, West Lafayette, IN); Brooks, Carlton, F.; Pyrak-Nolte, Laura J. (Purdue University, West Lafayette, IN); Liu, Yihong (Purdue University, West Lafayette, IN)

    2008-09-01

    This document contains a summary of the work performed under the LDRD project entitled 'Interface Physics in Microporous Media'. The presence of fluid-fluid interfaces, which can carry non-zero stresses, distinguishes multiphase flows from more readily understood single-phase flows. In this work the physics active at these interfaces has been examined via a combined experimental and computational approach. One of the major difficulties of examining true microporous systems of the type found in filters, membranes, geologic media, etc. is the geometric uncertainty. To help facilitate the examination of transport at the pore-scale without this complication, a significant effort has been made in the area of fabrication of both two-dimensional and three-dimensional micromodels. Using these micromodels, multiphase flow experiments have been performed for liquid-liquid and liquid-gas systems. Laser scanning confocal microscopy has been utilized to provide high resolution, three-dimensional reconstructions as well as time resolved, two-dimensional reconstructions. Computational work has focused on extending lattice Boltzmann (LB) and finite element methods for probing the interface physics at the pore scale. A new LB technique has been developed that provides over 100x speed up for steady flows in complex geometries. A new LB model has been developed that allows for arbitrary density ratios, which has been a significant obstacle in applying LB to air-water flows. A new reduced order model has been developed and implemented in finite element code for examining non-equilibrium wetting in microchannel systems. These advances will enhance Sandia's ability to quantitatively probe the rich interfacial physics present in microporous systems.

  15. Microporous aluminoborates with large channels: structural and catalytic properties.

    Science.gov (United States)

    Yang, Tao; Bartoszewicz, Agnieszka; Ju, Jing; Sun, Junliang; Liu, Zheng; Zou, Xiaodong; Wang, Yingxia; Li, Guobao; Liao, Fuhui; Martín-Matute, Belén; Lin, Jianhua

    2011-12-23

    Channel zapping: PKU-1 and newly synthesized PKU-2 (Al(2)B(5)O(9)(OH)(3)⋅n H(2)O; see picture) possess microporous structures with 18-ring and 24-ring channels, respectively. They show high reactivity and size selectivity in the cyanosilylation of aldehydes as heterogeneous Lewis acid catalysts. The different channel sizes determine the substrate selectivity. These examples demonstrate the potential of octahedron-based aluminoborate channels in catalysis. Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  16. Emulsion preparation for novel micro-porous polymeric hemi-shells

    CSIR Research Space (South Africa)

    Naidoo, Kersch

    2008-01-01

    Full Text Available -dichloromethane (DCM) oil phase and emulsification in an acidic polyvinyl alcohol (PVA) aqueous phase, micro-porous hemi-shells formed as solvent evaporated. CO2 gas evolution from the porogen created particles with an externally micro-porous shell and a large internal...

  17. Guest-responsive reversible swelling and enhanced fluorescence in a super-absorbent, dynamic microporous polymer.

    Science.gov (United States)

    Rao, K Venkata; Mohapatra, Sudip; Maji, Tapas Kumar; George, Subi J

    2012-04-10

    A swell idea! The guest-responsive reversible swelling and fluorescence enhancement of a dynamic, microporous polymer network is presented. Guest-induced breathing of hydrophobic pores imparts multi-functional properties, such as super-absorbency, phase-selective swelling of oil from water and encapsulation of C(60) (see figure), to this soft micro-porous organic polymer.

  18. Observation of microporous cesium salts of 12-tungstosilicic acid using scanning transmission electron microscopy.

    Science.gov (United States)

    Hiyoshi, Norihito; Kamiya, Yuichi

    2015-06-21

    Heteropolyanions and their arrays in microporous cesium salts of 12-tungstosilicic acid, Cs2.5H1.5[SiW12O40] and Cs4.0[SiW12O40], were observed by aberration-corrected scanning transmission electron microscopy. Microstructures that form micropores in the polyoxometalates were visualized.

  19. A Smörgåsbord of Separation Strategies Using Microporous Crystalline Materials

    NARCIS (Netherlands)

    Krishna, R.

    2014-01-01

    Ordered crystalline microporous materials such as zeolites, metal-organic frameworks and zeolitic imidazolate frameworks, with pores in the 3-20 Å range, offer considerable potential for use in a wide variety of separations in the process industries. For many separation tasks, microporous adsorbents

  20. Improved bioresorbable microporous intravascular stents for gene therapy.

    Science.gov (United States)

    Ye, Y W; Landau, C; Meidell, R S; Willard, J E; Moskowitz, A; Aziz, S; Carlisle, E; Nelson, K; Eberhart, R C

    1996-01-01

    Drug imbibing microporous stents are under development at a number of centers to enhance healing of the arterial wall after balloon coronary angioplasty procedures. The authors improved the mechanical strength and reservoir properties of a biodegradable microporous stent reported to this Society in 1994. A combined tubular/helical coil stent is readily fabricated by flotation/precipitation and casting/ winding techniques. A two stage solvent swelling technique allows precise adjustment of the surface hydrophilic/hydrophobic balance. These developments permit seven-fold improvement in drug capacity without significantly altering mechanical properties. Stents modified in this manner retain tensile and compressive strength and are suitable for remote deployment. Elution kinetics of these modified stents suggest they are suitable for gene delivery. Successful gene transfer and transmural expression have been demonstrated after implantation of stents impregnated with a recombinant adenovirus carrying a nuclear localizing beta-galactosidase reporter gene into rabbit carotid arteries. These studies suggest that surface modified, bioresorbable polymer stents ultimately may be useful adjunctive devices for gene transfer during percutaneous transluminal revascularization.

  1. SURFACE MODIFICATION OF POLYPROPYLENE MICROPOROUS MEMBRANE BY TETHERING POLYPEPTIDES

    Institute of Scientific and Technical Information of China (English)

    Zhen-mei Liu; Zhi-kang Xu; Mathias Ulbricht

    2006-01-01

    Two kinds of polypeptides were tethered onto the surface of polypropylene microporous membrane (PPMM)through a ring opening polymerization of L-glutamate N-carboxyanhydride initiated by amino groups which were introduced by ammonia plasma and γ-aminopropyl triethanoxysilane treatments. X-ray photoelectron spectroscopy (XPS), attenuated total reflectance Fourier transform infrared spectroscopy (FT-IR/ATR), scanning electron microscopy (SEM), together with water contact angle measurements were used to characterize the modified membranes. XPS analyses and FT-IR/ATR spectra demonstrated that polypeptides are actually grafted onto the membrane surface. The wettability of the membrane surface increases at first and then decreases with the increase in grafting degrees of polypeptide. Platelet adhesion and murine macrophage attachment experiments reveal an enhanced hemocompatibility for the polypeptide modified PPMMs. All these results give evidence that polypeptide grafting can simultaneously improve the hemocompatibility as well as reserve the hydrophobicity for the membrane, which will provide a potential approach to improve the performance of polypropylene hollow fiber microporous membrane used in artificial oxygenator.

  2. In vivo iontophoretic delivery of salmon calcitonin across microporated skin.

    Science.gov (United States)

    Vemulapalli, Viswatej; Bai, Yun; Kalluri, Haripriya; Herwadkar, Anushree; Kim, Hyun; Davis, Shawn P; Friden, Phil M; Banga, Ajay K

    2012-08-01

    The purpose of this study was to determine the effect of microneedle (MN) technology and its combination with iontophoresis (ITP) on the in vivo transdermal delivery of salmon calcitonin (sCT). Maltose MNs (500 µm) were used to porate skin prior to application of the drug, with or without ITP. Micropores created by maltose MNs were characterized by histological sectioning and calcein imaging studies, which indicated uniformity of the created micropores. In vivo studies were performed in hairless rats to assess the degree of enhancement achieved by ITP (0.2 mA/cm² for 1 h), MNs (81 MNs), and their combination. In vivo studies indicate a serum maximal concentration of 0.61 ± 0.42 ng/mL, 1.79 ± 0.72 ng/mL, and 5.51 ± 0.32 ng/mL for ITP, MNs, and combination treatment, respectively. MN treatment alone increased serum concentration 2.5-fold and the combination treatment increased the concentration ninefold as compared with iontophoretic treatment alone. Combination treatment of ITP and MNs resulted in the highest delivery of sCT and therapeutic levels were achieved within 5 min of administration.

  3. Microporous nano-MgO/diatomite ceramic membrane with high positive surface charge for tetracycline removal.

    Science.gov (United States)

    Meng, Xian; Liu, Zhimeng; Deng, Cheng; Zhu, Mengfu; Wang, Deyin; Li, Kui; Deng, Yu; Jiang, Mingming

    2016-12-15

    A novel microporous nano-MgO/diatomite ceramic membrane with high positive surface charge was prepared, including synthesis of precursor colloid, dip-coating and thermal decomposition. Combined SEM, EDS, XRD and XPS studies show the nano-MgO is irregularly distributed on the membrane surface or pore walls and forms a positively charged nano coating. And the nano-MgO coating is firmly attached to the diatomite membrane via SiO chemical bond. Thus the nano-MgO/diatomite membrane behaves strong electropositivity with the isoelectric point of 10.8. Preliminary filtration tests indicate that the as-prepared nano-MgO/diatomite membrane could remove approximately 99.7% of tetracycline in water through electrostatic adsorption effect. The desirable electrostatic property enables the nano-MgO/diatomite membrane to be a candidate for removal of organic pollutants from water. And it is convinced that there will be a great application prospect of charged ceramic membrane in water treatment field. Copyright © 2016 Elsevier B.V. All rights reserved.

  4. Preparation and characterization of microporous fibers for sample preparation and LC-MS determination of drugs.

    Science.gov (United States)

    Buszewski, Boguslaw; Nowaczyk, Jacek; Ligor, Tomasz; Olszowy, Pawel; Ligor, Magdalena; Wasiniak, Bartlomiej; Miekisch, Wolfram; Schubert, Jochen K; Amann, Anton

    2009-07-01

    The aim of this study was the preparation of polypyrrole (PPy) fibers for solid phase microextraction (SPME). PPy coatings were obtained during the electrochemical polymerization process. The utility of various metal wires (Fe, Cu, Ag, Cu/Ag, kanthal and medical stainless steel) as a support for polymers was compared. Various experimental conditions of the synthesis process such as scan rate, voltage limits and number of scans and deposition time were applied. The average polymer thickness was in the range of 7-125 microm and its weight was in the scope of 0.65-5.6 mg. Different techniques, mainly elemental analysis, Fourier transform infrared spectroscopy, microscopy, and chromatography were performed for the characterization of obtained fibers with microporous structure. The extraction efficiency of cardiovascular drugs (metoprolol, propranolol, oxprenolol, propafenone and mexiletine) by means of fibers was tested. The concentration of mentioned compounds in standard solution was in the span of 10-150 ng/mL. LC-MS was employed for determination of drugs in desorption solution. LODs varied from 0.013 to 1.51 ng/mL for metoprolol and mexiletine respectively. The repeatability of extraction was obtained with the RSD values lower than 10%.

  5. From microporous regular frameworks to mesoporous materials with ultrahigh surface area: dynamic reorganization of porous polymer networks.

    Science.gov (United States)

    Kuhn, Pierre; Forget, Aurélien; Su, Dangsheng; Thomas, Arne; Antonietti, Markus

    2008-10-08

    High surface area organic materials featuring both micro- and mesopores were synthesized under ionothermal conditions via the formation of polyaryltriazine networks. While the polytrimerization of nitriles in zinc chloride at 400 degrees C produces microporous polymers, higher reaction temperatures induce the formation of additional spherical mesopores with a narrow dispersity. The nitrogen-rich carbonaceous polymer materials thus obtained present surface areas and porosities up to 3300 m(2) g(-1) and 2.4 cm(3) g(-1), respectively. The key point of this synthesis relies on the occurrence of several high temperature polymerization reactions, where irreversible carbonization reactions coupled with the reversible trimerization of nitriles allow the reorganization of the dynamic triazine network. The ZnCl2 molten salt fulfills the requirement of a high temperature solvent, but is also required as catalyst. Thus, this dynamic polymerization system provides not only highly micro- and mesoporous materials, but also allows controlling the pore structure in amorphous organic materials.

  6. Characterization of cellulose acetate micropore membrane immobilized acylase I

    Institute of Scientific and Technical Information of China (English)

    郭永胜; 王杰; 宋锡谨

    2004-01-01

    This paper describes an innovative method for the immobilization of acylase I, which was entrapped into the CA-CTA micropore membrane. The most suitable casting solutions proportion for immobilizing the enzyme was ob tained through orthogonal experiment. Properties of the enzyme membrane were investigated and compared with those of free enzyme and blank membrane. The thermal stability and pH stability of the enzyme inside the membrane were changed by immobilization. The optimum pH was found to be 6.0, which changes 1.0 unit compared with that of free acylase I. The optimum temperature was found to be about 90 ℃C, which is higher than that of free acylase I (60 ℃). Experimental results showed that immobilization had effects on the kinetic parameters of acylase I.

  7. Modelling of cycling of lithium battery with microporous carbon electrode

    Directory of Open Access Journals (Sweden)

    D. Portnyagin

    2008-12-01

    Full Text Available Charge/discharge cycles of lithium cell with microporous carbon electrode under potentiodynamic control have been modelled. Predictions of the models with variable and constant diffusion coefficient neglecting the electric field inside the particle (CPM, DFM are compared to the predictions of the models with variable and constant diffusion coefficient in which electrostatic interaction inside the particles of carbon electrode (CPME, DFME is taken into account. There is observed a considerable difference between both. Electrostatic interactions of lithium ions with each other and the charge distributed inside the particle promote intercalation during the discharge of the cell and deintercalation during the charge. The dependance of the effect of hysteresis during the cycling of the cell on the rate of change of the applied voltage is studied. The larger is the speed of change of the applied voltage the more effective is hysteresis. We have also obtained concentration profiles at different stages of charge/discharge process.

  8. Microporous Cokes Formed in Zeolite Catalysts Enable Efficient Solar Evaporation

    KAUST Repository

    Wang, Jianjian

    2017-03-13

    Cokes are inevitably generated during zeolite-catalyzed reactions as deleterious side products that deactivate the catalyst. In this study, we in-situ converted cokes into carbons within the confined microporous zeolite structures and evaluated their performances as absorbing materials for solar-driven water evaporation. With a properly chosen zeolite, the cokederived carbons possessed ordered interconnected pores and tunable compositions. We found that the porous structure and the oxygen content in as-prepared carbons had important influences on their energy conversion efficiencies. Among various investigated carbon materials, the carbon derived from the methanol-to-olefins reaction over zeolite Beta gave the highest conversion efficiency of 72% under simulated sunlight with equivalent solar intensity of 2 suns. This study not only demonstrates the great potential of traditionally useless cokes for solar thermal applications but also provides new insights into the design of carbon-based absorbing materials for efficient solar evaporation.

  9. Electrochemically Produced Graphene for Microporous Layers in Fuel Cells.

    Science.gov (United States)

    Najafabadi, Amin Taheri; Leeuwner, Magrieta J; Wilkinson, David P; Gyenge, Előd L

    2016-07-01

    The microporous layer (MPL) is a key cathodic component in proton exchange membrane fuel cells owing to its beneficial influence on two-phase mass transfer. However, its performance is highly dependent on material properties such as morphology, porous structure, and electrical resistance. To improve water management and performance, electrochemically exfoliated graphene (EGN) microsheets are considered as an alternative to the conventional carbon black (CB) MPLs. The EGN-based MPLs decrease the kinetic overpotential and the Ohmic potential loss, whereas the addition of CB to form a composite EGN+CB MPL improves the mass-transport limiting current density drastically. This is reflected by increases of approximately 30 and 70 % in peak power densities at 100 % relative humidity (RH) compared with those for CB- and EGN-only MPLs, respectively. The composite EGN+CB MPL also retains the superior performance at a cathode RH of 20 %, whereas the CB MPL shows significant performance loss.

  10. Preparation of Microporous Membranes for Lithium ion battery

    Science.gov (United States)

    Ren, Xumei; Gu, Hui; Wu, Feng; Huang, Xuejie

    PVDF-HFP based microporous films were prepared by phase inverse process. PVDF-HFP copolymer powder was dissolved in a mixture of acetone and a PVDF non-solvent (glycerol). The proportion of non-solvent was low enough to allow the dissolution and high enough to allow the phase separation during evaporation. The ratio of PVDF/acetone/glycerol in weight was controlled to 10-15/85-75/5-10. The membrane exhibit a spongy structure without clearly outlined skin layers when wet method is used, while it has skin if dry method is applied. The effects of solution composition, exposure time prior to coagulation and temperature of the coagulation bath on the micro-structure of prepared membranes were investigated. The porosity increase with the content of non-solvent, and decrease with the concentration of PVDF.

  11. Microporous PVdF gel for lithium-ion batteries

    Science.gov (United States)

    Boudin, F.; Andrieu, X.; Jehoulet, C.; Olsen, I. I.

    A novel ionic conductor for lithium-ion batteries was developed. This electrolyte is based on a porous polymer matrix filled and swollen by a liquid. The polymer matrix obtained by phase inversion was characterized in terms of porosity and average pore size. The microporous PVdF gel formed by impregnation of this polymer matrix with liquid electrolyte exhibited a high equivalent conductivity and a good temperature stability. Complete lithium-ion batteries using this polymer-based electrolyte were manufactured with a new process. Preliminary cycling results show a good rate capability and a capacity evolution similar to that of regular lithium-ion cells. The interest of this technology, as many other lithium-polymer ones, also lies in the possibility of designing and manufacturing new battery shapes at lower cost.

  12. Wear and Friction Behavior of Metal Impregnated Microporous Carbon Composites

    Science.gov (United States)

    Goller, Gultekin; Koty, D. P.; Tewari, S. N.; Singh, M.; Tekin, A.

    1996-01-01

    Metal-matrix composites have been prepared by pressure-infiltration casting of copper-base alloy melts into microporous carbon preforms. The carbon preforms contained varying proportions of amorphous carbon and graphite. Load dependence of the wear and friction behavior of the composite pins has been examined under ambient conditions against cast-iron plates, using a pin-on-plate reciprocating wear tester. The wear resistance of the composite is significantly improved, as compared with the base alloy. Contrary to the normally expected behavior, the addition of graphite to the amorphous carbon does not reduce the friction coefficient, especially at high loads. The wear and friction behavior of the composites is very sensitive to the size and distribution of the microstructural constituents.

  13. Reactive Infiltration of Silicon Melt Through Microporous Amorphous Carbon Preforms

    Science.gov (United States)

    Sangsuwan, P.; Tewari, S. N.; Gatica, J. E.; Singh, M.; Dickerson, R.

    1999-01-01

    The kinetics of unidirectional capillary infiltration of silicon melt into microporous carbon preforms have been investigated as a function of the pore morphology and melt temperature. The infiltrated specimens showed alternating bands of dark and bright regions, which corresponded to the unreacted free carbon and free silicon regions, respectively. The decrease in the infiltration front velocity for increasing infiltration distances, is in qualitative agreement with the closed-form solution of capillarity driven fluid flow through constant cross section cylindrical pores. However, drastic changes in the thermal response and infiltration front morphologies were observed for minute differences in the preforms microstructure. This suggests the need for a dynamic percolation model that would account for the exothermic nature of the silicon-carbon chemical reaction and the associated pore closing phenomenon.

  14. Microporous carbonaceous adsorbents for CO2 separation via selective adsorption

    KAUST Repository

    Zhao, Yunfeng

    2015-01-01

    Selective adsorption of CO2 has important implications for many energy and environment-related processes, which require the separation of CO2 from other gases (e.g. N2 and CH4) with high uptakes and selectivity. The development of high-performance adsorbents is one of the most promising solutions to the success of these processes. The present review is focused on the state-of-the-art of carbon-based (carbonaceous) adsorbents, covering microporous inorganic carbons and microporous organic polymers, with emphasis on the correlation between their textural and compositional properties and their CO2 adsorption/separation performance. Special attention is given to the most recently developed materials that were not covered in previous reviews. We summarize various effective strategies (N-doping, surface functionalization, extra-framework ions, molecular design, and pore size engineering) for enhancing the CO2 adsorption capacity and selectivity of carbonaceous adsorbents. Our discussion focuses on CO2/N2 separation and CO2/CH4 separation, while including an introduction to the methods and criteria used for evaluating the performance of the adsorbents. Critical issues and challenges regarding the development of high-performance adsorbents as well as some overlooked facts and misconceptions are also discussed, with the aim of providing important insights into the design of novel carbonaceous porous materials for various selective adsorption based applications. This journal is © The Royal Society of Chemistry.

  15. Kinetic modelling of molecular hydrogen transport in microporous carbon materials.

    Science.gov (United States)

    Hankel, Marlies; Zhang, Hong; Nguyen, Thanh X; Bhatia, Suresh K; Gray, Stephen K; Smith, Sean C

    2011-05-07

    The proposal of kinetic molecular sieving of hydrogen isotopes is explored by employing statistical rate theory methods to describe the kinetics of molecular hydrogen transport in model microporous carbon structures. A Lennard-Jones atom-atom interaction potential is utilized for the description of the interactions between H(2)/D(2) and the carbon framework, while the requisite partition functions describing the thermal flux of molecules through the transition state are calculated quantum mechanically in view of the low temperatures involved in the proposed kinetic molecular sieving application. Predicted kinetic isotope effects for initial passage from the gas phase into the first pore mouth are consistent with expectations from previous modeling studies, namely, that at sufficiently low temperatures and for sufficiently narrow pore mouths D(2) transport is dramatically favored over H(2). However, in contrast to expectations from previous modeling, the absence of any potential barrier along the minimum energy pathway from the gas phase into the first pore mouth yields a negative temperature dependence in the predicted absolute rate coefficients-implying a negative activation energy. In pursuit of the effective activation barrier, we find that the minimum potential in the cavity is significantly higher than in the pore mouth for nanotube-shaped models, throwing into question the common assumption that passage through the pore mouths should be the rate-determining step. Our results suggest a new mechanism that, depending on the size and shape of the cavity, the thermal activation barrier may lie in the cavity rather than at the pore mouth. As a consequence, design strategies for achieving quantum-mediated kinetic molecular sieving of H(2)/D(2) in a microporous membrane will need, at the very least, to take careful account of cavity shape and size in addition to pore-mouth size in order to ensure that the selective step, namely passage through the pore mouth, is also

  16. Sorption of water by biochar: Closer look at micropores

    Science.gov (United States)

    Spokas, Kurt; Hall, Kathleen; Joseph, Stephan; Kammann, Claudia; Novak, Jeffrey; Gámiz, Beatriz; Cox, Lucia

    2017-04-01

    Typically, biochar has been assumed to increase total water content of the soil system and thereby positively influence plant-soil moisture hydraulics. In this work, we focused on water's interaction with micro-pores (biochar pores. The temporal scale of liquid water entry into biochar's pore network is very complex, with observed bubbling occurring days, weeks, and even months after a piece of biochar is immersed under water at ambient conditions. Elevated temperature biochar typically has a positive heat of immersion measured calorimetrically, whereas the calculated BET energy of sorption from a water sorption isotherm typically decrease with production temperatures. To further complicate matters, different pieces of biochar interact differently with water even though the entire batch was created in the same reactor at the same time and after liquid water exposure the physical structure of biochar is irreversibly altered, sometimes negligible other times catastrophically. Nevertheless, based on the estimations of diffusion coefficients in biochar from drying curve analyses, pore surface moieties do reduce the effective diffusivity of water vapor in biochar. Contrary to the rule of thumb in soil physics, where higher gas filled porosity correlates with higher soil moisture holding capacities, our results indicate that biochar's water sorption rate and capacity is actually reduced at ambient conditions by an increase in microporous volume. Thereby, biochar's hydrophobic behavior is partly due to the entrapment of gas within the air-filled porosity which prevents liquid water's entry, even though these biochars possess elevated gas phase sorption capacities (e.g., BET N2/CO2 surface areas).

  17. Micro-porous TiO2 thin films grown on surface of Ti substrate

    Institute of Scientific and Technical Information of China (English)

    WU Xiao-hong; QIN Wei; JIANG Zhao-hua; HU Xin-guo; Li Qing-fen

    2004-01-01

    Microporous titanium dioxide thin films have been grown on titanium plates by the micro-plasma oxidation method with different current densities (4, 6, 10 and 14 A/dm2). X-ray diffraction, scanning electronic microscopy and UV-Vis spectrophotometry were used to characterize the films. It is found that the films grown are microporous and consist of crystalline titanium dioxide. The micropore size and the content of anatase and rutile TiO2 phase increase with the applied voltage. The relatively higher degradation efficiency for rhodamine B is obtained in the film produced with a current density of 10 A/dm2.

  18. The nonlinear propagation of acoustic waves in a viscoelastic medium containing cylindrical micropores

    Institute of Scientific and Technical Information of China (English)

    Feng Yu-Lin; Liu Xiao-Zhou; Liu Jie-Hui; Ma Li

    2009-01-01

    Based on an equivalent medium approach,this paper presents a model describing the nonlinear propagation of acoustic waves in a viscoelastic medium containing cylindrical micropores. The influences of pores' nonlinear oscillations on sound attenuation,sound dispersion and an equivalent acoustic nonlinearity parameter are discussed. The calculated results show that the attenuation increases with an increasing volume fraction of mieropores. The peak of sound velocity and attenuation occurs at the resonant frequency of the micropores while the peak of the equivalent acoustic nonlinearity parameter occurs at the half of the resonant frequency of the micropores. Furthermore,multiple scattering has been taken into account,which leads to a modification to the effective wave number in the equivalent medium approach. We find that these linear and nonlinear acoustic parameters need to be corrected when the volume fraction of micropores is larger than 0.1%.

  19. Healing behavior of preexisting hydrogen micropores in aluminum alloys during plastic deformation

    Energy Technology Data Exchange (ETDEWEB)

    Toda, H., E-mail: toda@pse.tut.ac.jp [Department of Production Systems Engineering, Toyohashi University of Technology, Toyohashi, Aichi 441-8580 (Japan); Minami, K. [Department of Production Systems Engineering, Toyohashi University of Technology, Toyohashi, Aichi 441-8580 (Japan); Koyama, K.; Ichitani, K. [Furukawa-Sky Aluminum Corp., 1351, Uwanodai, Fukaya, Saitama 366-8511 (Japan); Kobayashi, M. [Department of Production Systems Engineering, Toyohashi University of Technology, Toyohashi, Aichi 441-8580 (Japan); Uesugi, K.; Suzuki, Y. [Japan Synchrotron Radiation Research Institute, Mikazuki-cho, Sayo-gun, Hyogo 679-5198 (Japan)

    2009-09-15

    Synchrotron X-ray microtomography was used to observe the shrinkage and annihilation behaviors of hydrogen micropores in three dimensions during hot and cold plastic deformation of an Al-Mg alloy. Whether complete healing of micropores is achieved after plastic deformation was examined by exposing the material to a high temperature after plastic deformation. Although micropores generally show a pattern of shrinking and closing, closer inspection of a single specimen revealed a variety of geometrically variable behaviors. It is noteworthy that some of the micropores are reinitiated in positions identical to those before their annihilation, even after an 8-22% macroscopic strain has been further applied after annihilation. We attribute local variations such as these to significant local strain variation, which we measured in a series of tomographic volumes by tracking the microstructural features.

  20. Citrate impairs the micropore diffusion of phosphate into pure and C-coated goethite

    Science.gov (United States)

    Mikutta, Christian; Lang, Friederike; Kaupenjohann, Martin

    2006-02-01

    Anions of polycarboxylic low-molecular-weight organic acids (LMWOA) compete with phosphate for sorption sites of hydrous Fe and Al oxides. To test whether the sorption of LMWOA anions decreases the accessibility of micropores (citrate-induced changes in microporosity and the phosphate sorption kinetics of synthetic goethite in the presence and absence of citrate in batch systems for 3 weeks (500 μM of each ion, pH 5). We also used C-coated goethite obtained after sorption of dissolved organic matter in order to simulate organic coatings in the soil. We analyzed our samples with N 2 adsorption and electrophoretic mobility measurements. Citrate clogged the micropores of both adsorbents by up to 13% within 1 h of contact. The micropore volume decreased with increasing concentration and residence time of citrate. In the absence of citrate, phosphate diffused into micropores of the pure and C-coated goethite. The C coating (5.6 μmol C m -2) did not impair the intraparticle diffusion of phosphate. In the presence of citrate, the diffusion of phosphate into the micropores of both adsorbents was strongly impaired. We attribute this to the micropore clogging and the ligand-induced dissolution of goethite by citrate. While the diffusion limitation of phosphate by citrate was stronger when citrate was added before phosphate to pure goethite, the order of addition of both ions to C-coated goethite had only a minor effect on the intraparticle diffusion of phosphate. Micropore clogging and dissolution of microporous hydrous Fe and Al oxides may be regarded as potential strategies of plants to cope with phosphate deficiency in addition to ligand-exchange.

  1. Catalytic effect of transition metals on microwave-induced degradation of atrazine in mineral micropores.

    Science.gov (United States)

    Hu, Erdan; Cheng, Hefa

    2014-06-15

    With their high catalytic activity for redox reactions, transition metal ions (Cu(2+) and Fe(3+)) were exchanged into the micropores of dealuminated Y zeolites to prepare effective microporous mineral sorbents for sorption and microwave-induced degradation of atrazine. Due to its ability to complex with atrazine, loading of copper greatly increased the sorption of atrazine. Atrazine sorption on iron-exchanged zeolites was also significantly enhanced, which was attributed to the hydrolysis of Fe(3+) polycations in mineral micropores and electrostatic interactions of protonated atrazine molecules with the negatively charged pore wall surface. Copper and iron species in the micropores also significantly accelerated degradation of the sorbed atrazine (and its degradation intermediates) under microwave irradiation. The catalytic effect was attributed to the easy reducibility and high oxidation activity of Cu(2+) and Fe(3+) species stabilized in the micropores of the zeolites. It was postulated that the surface species of transition metals (monomeric Cu(2+), Cu(2+)-O-Cu(2+) complexes, FeO(+), and dinuclear Fe-O-Fe-like species) in the mineral micropores were thermally activated under microwave irradiation, and subsequently formed highly reactive sites catalyzing oxidative degradation of atrazine. The transition metal-exchanged zeolites, particularly the iron-exchanged ones, were relatively stable when leached under acidic conditions, which suggests that they are reusable in sorption and microwave-induced degradation. These findings offer valuable insights on designing of effective mineral sorbents that can selectively uptake atrazine from aqueous solutions and catalyze its degradation under microwave irradiation.

  2. Asymmetric hydration structure around calcium ion restricted in micropores fabricated in activated carbons

    Science.gov (United States)

    Ohkubo, Takahiro; Kusudo, Tomoko; Kuroda, Yasushige

    2016-11-01

    The adsorbed phase and hydration structure of an aqueous solution of Ca(NO3)2 restricted in micropores fabricated in activated carbons (ACs) having different average pore widths (0.63 and 1.1 nm) were investigated with the analysis of adsorption isotherms and x-ray absorption fine structure (XAFS) spectra on Ca K-edge. The adsorbed density of Ca2+ per unit micropore volume in the narrower pore was higher than in the wider pore, while the adsorbed amount per unit mass of carbon with the narrower pore was half of the amount of ACs with the larger pore. On the other hand, variations in the bands assigned to double-electron (KM I) and 1s  →  3d excitations in XAFS spectra demonstrate the formation of a distorted hydration cluster around Ca2+ in the micropore, although the structural parameters of hydrated Ca2+ in the micropores were almost consistent with the bulk aqueous solution, as revealed by the analysis of extended XAFS (EXAFS) spectra. In contrast to the hydration structure of monovalent ions such as Rb+, which generally presents a dehydrated structure in smaller than 1 nm micropores in ACs, the present study clearly explains that the non-spherically-symmetric structure of hydrated Ca2+ restricted in carbon micropores whose sizes are around 1 nm is experimentally revealed where any dehydration phenomena from the first hydration shell around Ca2+ could not be observed.

  3. Triptycene dimethyl-bridgehead dianhydride-based intrinsically microporous hydroxyl-functionalized polyimide for natural gas upgrading

    KAUST Repository

    Alghunaimi, Fahd

    2016-07-28

    The synthesis and gas permeation properties of a high-performance hydroxyl-functionalized PIM-polyimide (TDA1-APAF) prepared from a novel 9,10-dimethyl-2,3,6,7-triptycene tetracarboxylic dianhydride (TDA1) and a commercially available 2,2-bis(3-amino-4-hydroxyphenyl)-hexafluoropropane (APAF) diamine monomer are reported. The microporous polymer had a BET surface area based on nitrogen adsorption of 260 m2 g−1. A freshly prepared sample exhibited excellent gas permeation properties: (i) CO2 permeability of 40 Barrer coupled with a CO2/CH4 selectivity of 55 and (ii) H2 permeability of 94 Barrer with a H2/CH4 selectivity of 129. Physical aging over 250 days resulted in significantly enhanced CO2/CH4 and H2/CH4 selectivities of 75 and 183, respectively with only ~ 25% loss in CO2 and H2 permeability. Aged TDA1-APAF exhibited 5-fold higher pure-gas CO2 permeability (30 Barrer) and two-fold higher CO2/CH4 permselectivity over conventional dense cellulose triacetate membranes at 2 bar. In addition, TDA1-APAF polyimide had a N2/CH4 selectivity of 2.3, thereby making it potentially possible to bring natural gas with low, but unacceptable nitrogen content to pipeline specification. Gas mixture permeation experiments with a 1:1 CO2/CH4 feed mixture demonstrated higher mixed- than pure-gas selectivity and plasticization resistance up to 30 bar. These results suggest that intrinsically microporous hydroxyl-functionalized triptycene-based polyimides are promising candidate membrane materials for removal of CO2 from natural gas and hydrogen purification in petrochemical refinery applications.

  4. Microporous gel electrolytes based on amphiphilic poly(vinylidene fluoride-co-hexafluoropropylene) for lithium batteries

    Science.gov (United States)

    Yu, Shicheng; Chen, Lie; Chen, Yiwang; Tong, Yongfen

    2012-03-01

    Poly(vinylidene fluoride-co-hexafluoropropylene) grafted poly(poly(ethylene glycol) methyl ether methacrylate) (PVDF-HFP-g-PPEGMA) is simply prepared by single-step synthesis directly via atom transfer radical polymerization (ATRP) of poly(ethylene glycol) methyl ether methacrylate (PEGMA) from poly(vinylidene fluoride-co-hexafluoropropylene) (PVDF-HFP). Thermal, mechanical, swelling and electrochemical properties, as well as microstructures of the prepared polymer electrolytes, are evaluated and the effects of the various contents and average molecular weights of PEGMA on those properties are also been investigated. By phase inversion technique, the copolymer membranes tend to form well-defined microporous morphology with the increase of content and average molecular weight of PEGMA, due to the competition and cooperation between the hydrophilic PEGMA segments and hydrophobic PVDF-HFP. When these membranes are gelled with 1 M LiCF3SO3 in ethylene carbonate (EC)/propylene carbonate (PC) (1:1, v/v), their saturated electrolyte uptakes (up to 323.5%) and ion conductivities (up to 2.01 × 10-3 S cm-1) are dramatically improved with respect to the pristine PVDF-HFP, ascribing to the strong affinity of the hydrophilic PEGMA segments with the electrolytes. All the polymer electrolytes are electrochemically stable up to 4.7 V versus Li/Li+, and show good mechanical properties. Coin cells based on the polymer electrolytes show stable charge-discharge cycles and deliver discharge capacities to LiFePO4 is up to 156 mAh g-1.

  5. Microporous gel electrolytes based on amphiphilic poly(vinylidene fluoride-co-hexafluoropropylene) for lithium batteries

    Energy Technology Data Exchange (ETDEWEB)

    Yu Shicheng [Institute of Polymers, Nanchang University, 999 Xuefu Avenue, Nanchang 330031 (China); Chen Lie, E-mail: chenlienc@163.com [Institute of Polymers, Nanchang University, 999 Xuefu Avenue, Nanchang 330031 (China) and Jiangxi Provincial Key Laboratory of New Energy Chemistry, Nanchang University, 999 Xuefu Avenue, Nanchang 330031 (China); Chen Yiwang, E-mail: ywchen@ncu.edu.cn [Institute of Polymers, Nanchang University, 999 Xuefu Avenue, Nanchang 330031 (China); Jiangxi Provincial Key Laboratory of New Energy Chemistry, Nanchang University, 999 Xuefu Avenue, Nanchang 330031 (China); Tong Yongfen [Institute of Polymers, Nanchang University, 999 Xuefu Avenue, Nanchang 330031 (China); School of Environmental and Chemical Engineering, Nanchang Hangkong University, 696 Fenghe South Avenue, Nanchang 330063 (China)

    2012-03-15

    Poly(vinylidene fluoride-co-hexafluoropropylene) grafted poly(poly(ethylene glycol) methyl ether methacrylate) (PVDF-HFP-g-PPEGMA) is simply prepared by single-step synthesis directly via atom transfer radical polymerization (ATRP) of poly(ethylene glycol) methyl ether methacrylate (PEGMA) from poly(vinylidene fluoride-co-hexafluoropropylene) (PVDF-HFP). Thermal, mechanical, swelling and electrochemical properties, as well as microstructures of the prepared polymer electrolytes, are evaluated and the effects of the various contents and average molecular weights of PEGMA on those properties are also been investigated. By phase inversion technique, the copolymer membranes tend to form well-defined microporous morphology with the increase of content and average molecular weight of PEGMA, due to the competition and cooperation between the hydrophilic PEGMA segments and hydrophobic PVDF-HFP. When these membranes are gelled with 1 M LiCF{sub 3}SO{sub 3} in ethylene carbonate (EC)/propylene carbonate (PC) (1:1, v/v), their saturated electrolyte uptakes (up to 323.5%) and ion conductivities (up to 2.01 Multiplication-Sign 10{sup -3} S cm{sup -1}) are dramatically improved with respect to the pristine PVDF-HFP, ascribing to the strong affinity of the hydrophilic PEGMA segments with the electrolytes. All the polymer electrolytes are electrochemically stable up to 4.7 V versus Li/Li{sup +}, and show good mechanical properties. Coin cells based on the polymer electrolytes show stable charge-discharge cycles and deliver discharge capacities to LiFePO{sub 4} is up to 156 mAh g{sup -1}.

  6. Fabrication of resorbable microporous intravascular stents for gene therapy applications.

    Science.gov (United States)

    Rajasubramanian, G; Meidell, R S; Landau, C; Dollar, M L; Holt, D B; Willard, J E; Prager, M D; Eberhart, R C

    1994-01-01

    The authors have produced resorbable, microporous endoluminal stents from Poly-L-lactic acid (PLLA)/Poly epsilon-caprolactone (PCL) blends. Both helical and tube stent designs have been obtained by solvent casting and flotation-precipitation fabrication techniques. A range of PLLA/PCL blend ratios and process variables were employed to investigate their influence on mechanical properties, porosity, and degradation rate. Polymer blends with higher PLLA proportions exhibit higher elastic moduli and ultimate tensile strength, and lower elongation, porosity, and degradation rates than do materials with higher PCL content. Stents with suitable mechanical properties for deployment and support of the vessel wall were obtained. Poly(ethylene oxide) was incorporated into these devices using an acid swelling technique, opening the pore structure and improving the hydrophilic character, thereby enabling the uptake of recombinant adenoviral vectors. The 50:50 PLLA/PCL blended stents were impregnated with recombinant adenovirus (AdCMB beta Gal, encoding a nuclear localizing variant of Escherichia coli beta-galactosidase). Cultured CV-1 cells incubated with stents impregnated with the recombinant virus expressed nuclear localized beta-galactosidase activity, confirming that absorbed virus is released from the matrix in an infectious form, with kinetics suggesting that genetically enhanced endovascular devices of this design are feasible.

  7. Microporous device for local electric recordings on model lipid bilayers

    Science.gov (United States)

    Kaufeld, Theresa; Steinem, Claudia; Schmidt, Christoph F.

    2015-01-01

    A powerful approach for characterizing lipid membranes and embedded proteins is the reconstitution of model lipid bilayers. The extreme fragility of 5 nm thick bilayers is a challenge for device design and requires a trade off of stability against accessibility. We here present a microporous lab-on-chip device that allows us to form stable, solvent-free lipid bilayers from giant unilamellar vesicles (GUVs) in a geometry that provides a unique set of access possibilities. The device is constructed around a micro-fabricated silicon chip with clusters of 1 µm-diameter pores and provides optical access to the lipid bilayers for high-NA epifluorescence imaging. At the same time, solvent exchange is possible on both sides of the lipid bilayer. Complete coverage can be achieved with GUVs, so that voltages can be applied across the lipid bilayer and single-channel currents can be measured using external or integrated silver/silver chloride electrodes. We describe the micro-fabrication by standard cleanroom techniques and the characterization of the device by atomic force microscopy, scanning electron microscopy and impedance spectroscopy. In proof-of-concept experiments we demonstrate that the device is capable of low-noise, single-ion-channel recordings. Electronic Supplementary Information (ESI) available: See DOI: 10.1039/b000000x/

  8. A framework for predicting surface areas in microporous coordination polymers.

    Science.gov (United States)

    Schnobrich, Jennifer K; Koh, Kyoungmoo; Sura, Kush N; Matzger, Adam J

    2010-04-20

    A predictive tool termed the linker to metal cluster (LiMe) ratio is introduced as a method for understanding surface area in microporous coordination polymers (MCPs). Calibrated with geometric accessible surface area computations, the LiMe ratio uses molecular weight of building block components to indicate the maximum attainable surface area for a given linker and metal cluster combination. MOF-5 and HKUST-1 are used as prototypical structures to analyze MCPs with octahedral M(4)O(CO(2)R)(6) and paddlewheel M(2)(CO(2)R)(4) metal clusters. Insight into the effects of linker size, geometry, number of coordinating groups, and framework interpenetration is revealed through the LiMe ratio analysis of various MCPs. Experimental surface area deviation provides indication that a material may suffer from incomplete guest removal, structural collapse, or interpenetration. Because minimal data input are required, the LiMe ratio surface area analysis is suggested as a quick method for experimental verification as well as a guide for the design of new materials.

  9. Microporous silica gels from alkylsilicate-water two phase hydrolysis

    Energy Technology Data Exchange (ETDEWEB)

    Chu, L.; Tejedor-Tejedor, M.I.; Anderson, M.A. [Univ. of Wisconsin, Madison, WI (United States). Water Chemistry Program

    1994-12-31

    Microporous silica gels have been synthesized through a nano-particulate sol-gel route. These gels have uniformly distributed and extremely small pores(< 15 {angstrom} in diameter). Hydrolysis and condensation reactions leading to these gels were carried out in an alkyl silicate-water (ammonia) two phase system. These reactions took place at the alkyl silicate droplet-water interfacial boundary. No alcohol was added. A clear, stable and uniformly distributed colloidal silica suspension having an average particle size less than 6 nm was prepared by this method. Fast hydrolysis, slow condensation and low solubility all contribute to a high supersaturation level and result in the formation of small particles. This process is consistent with classic nucleation theory. When the particles are produced under acidic rather than under basic reaction conditions, smaller particles are formed due to the slower condensation rate and lower solubility of these silica particles in acidic conditions. At the same pH, alkylsilicates having smaller alkyl groups react faster with water leading to smaller primary particles. Homogeneous nucleation conditions are achieved when the water/alkylsilicate ratio is high.

  10. Separating mixtures by exploiting molecular packing effects in microporous materials.

    Science.gov (United States)

    Krishna, Rajamani

    2015-01-07

    We examine mixture separations with microporous adsorbents such as zeolites, metal-organic frameworks (MOFs) and zeolitic imidazolate frameworks (ZIFs), operating under conditions close to pore saturation. Pore saturation is realized, for example, when separating bulk liquid phase mixtures of polar compounds such as water, alcohols and ketones. For the operating conditions used in industrial practice, pore saturation is also attained in separations of hydrocarbon mixtures such as xylene isomers and hexane isomers. Separations under pore saturation conditions are strongly influenced by differences in the saturation capacities of the constituent species; the adsorption is often in favor of the component with the higher saturation capacity. Effective separations are achieved by exploiting differences in the efficiency with which molecules pack within the ordered crystalline porous materials. For mixtures of chain alcohols, the shorter alcohol can be preferentially adsorbed because of its higher saturation capacity. With hydrophilic adsorbents, water can be selectively adsorbed from water-alcohol mixtures. For separations of o-xylene-m-xylene-p-xylene mixtures, the pore dimensions of MOFs can be tailored in such a manner as to allow optimal packing of the isomer that needs to be adsorbed preferentially. Subtle configurational differences between linear and branched alkane isomers result in significantly different packing efficiencies within the pore topology of MFI, AFI, ATS, and CFI zeolites. A common characteristic feature of most separations that are reliant on molecular packing effects is that adsorption and intra-crystalline diffusion are synergistic; this enhances the separation efficiencies in fixed bed adsorbers.

  11. Microporous separators for Fe/V redox flow batteries

    Science.gov (United States)

    Wei, Xiaoliang; Li, Liyu; Luo, Qingtao; Nie, Zimin; Wang, Wei; Li, Bin; Xia, Guan-Guang; Miller, Eric; Chambers, Jeff; Yang, Zhenguo

    2012-11-01

    The Fe/V redox flow battery has demonstrated promising performance with distinct advantages over other redox flow battery systems. Due to the less oxidative nature of the Fe(III) species, hydrocarbon-based ion exchange membranes or separators can be used. Daramic® microporous polyethylene separators were tested on Fe/V flow cells using sulphuric/chloric mixed acid-supporting electrolytes. Among them, separator C exhibited good flow cell cycling performance with satisfactory repeatability over a broad temperature range of 5-50 °C. Energy efficiency (EE) of C remains around 70% at current densities of 50-80 mA cm-2 in temperatures ranging from room temperature to 50 °C. The capacity decay problem could be circumvented through hydraulic pressure balancing by means of applying different pump rates to the positive and negative electrolytes. Stable capacity and energy were obtained over 20 cycles at room temperature and 40 °C. These results show that extremely low-cost separators ($1-20 m-2) are applicable in the Fe/V flow battery system with acceptable energy efficiency. This represents a remarkable breakthrough: a significant reduction of the capital cost of the Fe/V flow battery system, which could further its market penetration in grid stabilization and renewable integration.

  12. Site-specific metal and ligand substitutions in a microporous Mn(2+)-based metal-organic framework.

    Science.gov (United States)

    Huxley, Michael; Coghlan, Campbell J; Burgun, Alexandre; Tarzia, Andrew; Sumida, Kenji; Sumby, Christopher J; Doonan, Christian J

    2016-03-14

    The precise tuning of the structural and chemical features of microporous metal-organic frameworks (MOFs) is a crucial endeavour for developing materials with properties that are suitable for specific applications. In recent times, techniques for preparing frameworks consisting of mixed-metal or ligand compositions have emerged. However, controlled spatial organisation of the components within these structures at the molecular scale is a difficult challenge, particularly when species possessing similar geometries or chemical properties are used. Here, we describe the synthesis of mixed-metal and ligand variants possessing the Mn3L3 (Mn-MOF-1; H2L = bis(4-(4'-carboxyphenyl)-3,5-dimethylpyrazolyl)methane) structure type. In the case of mixed-ligand synthesis using a mixture of L and its trifluoromethyl-functionalised derivative (H2L' = bis(4-(4'-carboxyphenyl)-3,5-di(trifluoromethyl)pyrazolyl)methane), a mixed-ligand product in which the L' species predominanantly occupies the pillar sites lining the pores is obtained. Meanwhile, post-synthetic metal exchange of the parent Mn3L3 compound using Fe(2+) or Fe(3+) ions results in a degree of cation exchange at the trinuclear carboxylate-based clusters and metalation at the pillar bispyrazolate sites. The results demonstrate the versatility of the Mn3L3 structure type toward both metal and ligand substitutions, and the potential utility of site-specific functionalisations in achieving even greater precision in the tuning of MOFs.

  13. Growth of Casting Microcrack and Micropore in Single-crystal Superalloys Analysed by Three-Dimensional Unit Cell

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    Finite element (FE) analysis was employed to investigate the casting microcrack and micropore growth in nickel-base single-crystal superalloys DD3. Based on the finite deformation rate-dependent crystallographic constitutive equation, the simulations of casting microcrack and micropore growth in three-dimensional unit cell model were carried out in a range of parameters including stress triaxiality, Lode parameter and type of activated slip systems. The FE results show that the stress triaxiality has profound effects on growth behavior,and the Lode parameter is also important for the casting microcrack and micropore growth. The type of operative slip systems has remarkable effect on casting microcrack and micropore growth, so the life of singlecrystal component is associated with the type of activated slip systems, which is related to Schmid factor and the number of activated slip systems. The growth comparison between microcrack and micropore reveals that when the material is subjected to large deformation, the growth rate of microcrack is faster than that of micropore, i.e. microcrack is more dangerous than micropore; the microcrack is easier to result in brittle fracture than micropore. The stress triaxiality and Lode parameter have strong influence on the growth of microcrack and micropore.

  14. Development of an alternating magnetic-field-assisted finishing process for microelectromechanical systems micropore x-ray optics.

    Science.gov (United States)

    Riveros, Raul E; Yamaguchi, Hitomi; Mitsuishi, Ikuyuki; Takagi, Utako; Ezoe, Yuichiro; Kato, Fumiki; Sugiyama, Susumu; Yamasaki, Noriko; Mitsuda, Kazuhisa

    2010-06-20

    X-ray astronomy research is often limited by the size, weight, complexity, and cost of functioning x-ray optics. Micropore optics promises an economical alternative to traditional (e.g., glass or foil) x-ray optics; however, many manufacturing difficulties prevent micropore optics from being a viable solution. Ezoe et al. introduced microelectromechanical systems (MEMS) micropore optics having curvilinear micropores in 2008. Made by either deep reactive ion etching or x-ray lithography, electroforming, and molding (LIGA), MEMS micropore optics suffer from high micropore sidewall roughness (10-30nmrms) which, by current standards, cannot be improved. In this research, a new alternating magnetic-field-assisted finishing process was developed using a mixture of ferrofluid and microscale abrasive slurry. A machine was built, and a set of working process parameters including alternating frequency, abrasive size, and polishing time was selected. A polishing experiment on a LIGA-fabricated MEMS micropore optic was performed, and a change in micropore sidewall roughness of 9.3+/-2.5nmrms to 5.7+/-0.7nmrms was measured. An improvement in x-ray reflectance was also seen. This research shows the feasibility and confirms the effects of this new polishing process on MEMS micropore optics.

  15. Micropore closure kinetics are delayed following microneedle insertion in elderly subjects.

    Science.gov (United States)

    Kelchen, Megan N; Siefers, Kyle J; Converse, Courtney C; Farley, Matthew J; Holdren, Grant O; Brogden, Nicole K

    2016-03-10

    Transdermal delivery is an advantageous method of drug administration, particularly for an elderly population. Microneedles (MNs) allow transdermal delivery of otherwise skin-impermeable drugs by creating transient micropores that bypass the barrier function of the skin. The response of aging skin to MNs has not been explored, and we report for the first time that micropore closure is delayed in elderly subjects in a manner that is dependent upon MN length, number, and occlusion of the micropores. Twelve control subjects (25.6±2.8years) and 16 elderly subjects (77.3±6.8years) completed the study. Subjects were treated with MNs of 500μm or 750μm length, in arrays containing 10 or 50 MNs. Impedance measurements made at baseline, post-MN insertion, and at predetermined time points demonstrated that restoration of the skin barrier is significantly slower in elderly subjects under both occluded and non-occluded conditions. This was confirmed via calculation of the total permeable area created by the micropores (which would approximate the area available for drug delivery), as well as calculation of the micropore half-life. This pilot study demonstrates that longer timeframes are required to restore the barrier function of aged skin following MN insertion, suggesting that drug delivery windows could be longer following one treatment with a MN array.

  16. Random lasing of microporous surface of Cr2+:ZnSe crystal induced by femtosecond laser

    Directory of Open Access Journals (Sweden)

    Xianheng Yang

    2015-06-01

    Full Text Available We demonstrate a random lasing emission based on microporous surface of Cr2+:ZnSe crystal prepared by femtosecond pulsed laser ablation in high vacuum (below 5 × 10−4 Pa. The scanning electron microscope results show that there are a mass of micropores with an average size of ∼13 μm and smaller ones with ∼1.2 μm on the surface of Cr2+:ZnSe crystal. The adjacent micropore spacing of the smaller micropores ranges from 1 μm to 5 μm. Under 1750 nm excitation of Nd:YAG (355 nm pumped optical parametric oscillator, a random lasing emission with center wavelength of 2350 nm and laser-like threshold of 0.3 mJ/pulse is observed. The emission lifetime of 2350 nm laser reduces from 800 ns to 30 ns as the pump energy increases above threshold. The emission spectra and decay time of smooth surface, groove and microporous surface of Cr2+:ZnSe crystal are contrasted. The optional pump wavelength range is from 1500 nm to 1950 nm, which in accordance with the optical absorption property of Cr2+:ZnSe crystal. The peak position of excitation spectra is almost identical to the strongest absorption wavelength.

  17. Electrochemically deposited and etched membranes with precisely sized micropores for biological fluids microfiltration

    Science.gov (United States)

    Hamzah, A. A.; Zainal Abidin, H. E.; Yeop Majlis, B.; Mohd Nor, M.; Ismardi, A.; Sugandi, G.; Tiong, T. Y.; Dee, C. F.; Yunas, J.

    2013-07-01

    This paper presents simple and economical, yet reliable techniques to fabricate a micro-fluidic filter for MEMS lab-on-chip (LoC) applications. The microporous filter is a crucial component in a MEMS LoC system. Microsized components and contaminants in biological fluids are selectively filtered using copper and silicon membranes with precisely controlled microsized pores. Two techniques were explored in microporous membrane fabrication, namely copper electroplating and electrochemical etching (ECE) of silicon. In the first technique, a copper membrane with evenly distributed micropores was fabricated by electroplating the copper layer on the silicon nitride membrane, which was later removed to leave the freestanding microporous membrane structure. The second approach involves the thinning of bulk silicon down to a few micrometers thick using KOH and etching the resulting silicon membrane in 5% HF by ECE to create micropores. Upon testing with nanoparticles of various sizes, it was observed that electroplated copper membrane passes nanoparticles up to 200 nm wide, while porous silicon membrane passes nanoparticles up to 380 nm in size. Due to process compatibility, simplicity, and low-cost fabrication, electroplated copper and porous silicon membranes enable synchronized microfilter fabrication and integration into the MEMS LoC system.

  18. An activated microporous carbon prepared from phenol-melamine-formaldehyde resin for lithium ion battery anode

    Energy Technology Data Exchange (ETDEWEB)

    Zhu, Yinhai; Xiang, Xiaoxia [Key Laboratory of Environmentally Friendly Chemistry and Applications of Ministry of Education, College of Chemistry, Xiangtan University, Hunan 411105 (China); Liu, Enhui, E-mail: liuenhui99@sina.com.cn [Key Laboratory of Environmentally Friendly Chemistry and Applications of Ministry of Education, College of Chemistry, Xiangtan University, Hunan 411105 (China); Wu, Yuhu; Xie, Hui; Wu, Zhilian; Tian, Yingying [Key Laboratory of Environmentally Friendly Chemistry and Applications of Ministry of Education, College of Chemistry, Xiangtan University, Hunan 411105 (China)

    2012-08-15

    Highlights: ► Microporous carbon was prepared by chemical activation of phenol-melamine-formaldehyde resin. ► Activation leads to high surface area, well-developed micropores. ► Micropores lead to strong intercalation between carbon and lithium ion. ► Large surface area promotes to improve the lithium storage capacity. -- Abstract: Microporous carbon anode materials were prepared from phenol-melamine-formaldehyde resin by ZnCl{sub 2} and KOH activation. The physicochemical properties of the obtained carbon materials were characterized by scanning electron microscope, X-ray diffraction, Brunauer–Emmett–Teller, and elemental analysis. The electrochemical properties of the microporous carbon as anode materials in lithium ion secondary batteries were evaluated. At a current density of 100 mA g{sup −1}, the carbon without activation shows a first discharge capacity of 515 mAh g{sup −1}. After activation, the capacity improved obviously. The first discharge capacity of the carbon prepared by ZnCl{sub 2} and KOH activation was 1010 and 2085 mAh g{sup −1}, respectively. The reversible capacity of the carbon prepared by KOH activation was still as high as 717 mAh g{sup −1} after 20 cycles, which was much better than that activated by ZnCl{sub 2}. These results demonstrated that it may be a promising candidate as an anode material for lithium ion secondary batteries.

  19. Restricted access: on the nature of adsorption/desorption hysteresis in amorphous, microporous polymeric materials.

    Science.gov (United States)

    Jeromenok, Jekaterina; Weber, Jens

    2013-10-22

    The phenomenon of low-pressure adsorption/desorption hysteresis, which is commonly observed in microporous polymers, is investigated by detailed gas adsorption studies. Diffusional limitations by pore blocking effects, which arise as a consequence of the micropore morphology and connectivity, are discussed as the origin of the hysteresis rather than swelling effects, which have been suggested previously. Micropores with narrow openings, which cannot be filled easily, are expected to be present next to open pores. Those pores are termed restricted-access pores and are only filled in the course of the adsorption process as a consequence of the increasing solvation pressure exhibited from already filled micropores. As a consequence of the results presented here, it is suggested to use the desorption branch in addition to the adsorption branch for the extraction of the porosity characteristics, such as specific surface area, pore volume, and pore size distribution. The magnitude of the low-pressure hysteresis might hence give an idea of the micropore connectivity, which is important information for potential applications.

  20. Microporous-mesoporous carbons for energy storage synthesized by activation of carbonaceous material by zinc chloride, potassium hydroxide or mixture of them

    Science.gov (United States)

    Härmas, M.; Thomberg, T.; Kurig, H.; Romann, T.; Jänes, A.; Lust, E.

    2016-09-01

    Various electrochemical methods have been applied to establish the electrochemical characteristics of the electrical double layer capacitor (EDLC) consisting of the 1 M triethylmethylammonium tetrafluoroborate solution in acetonitrile and activated carbon based electrodes. Activated microporous carbon materials used for the preparation of electrodes have been synthesized from the hydrothermal carbonization product (HTC) prepared via hydrothermal carbonization process of D-(+)-glucose solution in H2O, followed by activation with ZnCl2, KOH or their mixture. Highest porosity and Brunauer-Emmett-Teller specific surface area (SBET = 2150 m2 g-1), micropore surface area (Smicro = 2140 m2 g-1) and total pore volume (Vtot = 1.01 cm3 g-1) have been achieved for HTC activated using KOH with a mass ratio of 1:4 at 700 °C. The correlations between SBET, Smicro, Vtot and electrochemical characteristics have been studied to investigate the reasons for strong dependence of electrochemical characteristics on the synthesis conditions of carbon materials studied. Wide region of ideal polarizability (ΔV ≤ 3.0 V), very short characteristic relaxation time (0.66 s), and high specific series capacitance (134 F g-1) have been calculated for the mentioned activated carbon material, demonstrating that this system can be used for completing the EDLC with high energy- and power densities.

  1. Ultrananocrystalline Diamond-Coated Microporous Silicon Nitride Membranes for Medical Implant Applications

    Science.gov (United States)

    Skoog, Shelby A.; Sumant, Anirudha V.; Monteiro-Riviere, Nancy A.; Narayan, Roger J.

    2012-04-01

    Ultrananocrystalline diamond (UNCD) exhibits excellent biological and mechanical properties, which make it an appropriate choice for promoting epidermal cell migration on the surfaces of percutaneous implants. We deposited a ~150 nm thick UNCD film on a microporous silicon nitride membrane using microwave plasma chemical vapor deposition. Scanning electron microscopy and Raman spectroscopy were used to examine the pore structure and chemical bonding of this material, respectively. Growth of human epidermal keratinocytes on UNCD-coated microporous silicon nitride membranes and uncoated microporous silicon nitride membranes was compared using the 3-(4,5-dimethylthiazol-2-yl)2,5-diphenyltetrazolium bromide (MTT) assay. The results show that the UNCD coating did not significantly alter the viability of human epidermal keratinocytes, indicating potential use of this material for improving skin sealing around percutaneous implants.

  2. Determination of Energy Characteristic and Microporous Volume by Immersion Calorimetry in Carbon Monoliths

    Directory of Open Access Journals (Sweden)

    Juan Carlos Moreno-Piraján

    2012-01-01

    Full Text Available Activated carbon monoliths disc and honeycomb type were prepared by chemical activation of coconut shell with zinc chloride at different concentrations, without using a binder. The structures were characterized by N2 adsorption at 77 K and immersion calorimetry into benzene. The experimental results showed that the activation with zinc chloride produces a wide microporous development, with micropore volume between 0,38 and 0,79 cm3g-1, apparent BET surface area between 725 and 1523 m2g-1 and immersion enthalpy between 73,5 and 164,2 Jg-1. We compared the experimental enthalpy with calculated enthalpy by equation Stoeckli-Kraehenbuehl finding a data dispersion from which can infer that the structures are not purely microporous; this fact is ratified with similar behavior that the evidence t the product EoWo.

  3. Hierarchically Structured Graphene Coupled Microporous Organic Polymers for Superior CO2 Capture.

    Science.gov (United States)

    Liu, Fa-Qian; Wang, Li-Li; Li, Guo-Hua; Li, Wei; Li, Chao-Qin

    2017-10-04

    Hierarchically porous materials containing interconnected macro-/meso-/micropores are promising candidates for energy storage, catalysis, and gas separation. Here, we present an effective approach for synthesizing three-dimensional (3D) sulfonated graphene coupled microporous organic polymers (SG-MOPs). The resulting SG-MOPs possess uniform macropores with an average size of ca. 350 nm, abundant mesopores, and micropores with an average size of ca. 0.6 nm. The SG-supported adsorbents exhibit a high nitrogen content (more than 38.1 wt %), high adsorption capacity (up to 3.37 mmol CO2 g(-1)), high CO2/N2 selectivity from 42 to 51, moderate heat of adsorption, as well as good stability because of the hierarchical porous structure and excellent thermal conductivity of the SG scaffold. Thus, these nitrogen-enriched adsorbents allow the overall CO2 capture process to be promising and sustainable.

  4. Influence of carbonization conditions on micro-pore structure of foundry formed coke produced with char

    Energy Technology Data Exchange (ETDEWEB)

    Jun Qiao; Jianjun Wu; Jingru Zu; Zhiyuan Gao; Guoli Zhou

    2009-07-01

    There are few studies on coke's micro-pore structure in recent years, however, micro-pore structure of foundry coke determines its macroscopically quality index and reactivity in cupola furnace. Effect of such factors on micro-pore structure were investigated under different carbonization conditions with certain ratio of raw materials and material forming process in this article as charging temperature (A); braised furnace time (B); heating rate of the first stage (C)and the second stage (D) and holding time of ultimate temperature (E). Research showed that charging temperature was the most influential factor on the coke porosity, pore volume, pore size and specific surface area. It is suggested that formation of plastic mass and releasing rate of volatile during carbonization period are two main factors on microstructure of foundry coke while charging temperature contributes most to the above factors. 6 refs., 4 figs., 9 tabs.

  5. Organic Microporous Nanofillers with Unique Alcohol Affinity for Superior Ethanol Recovery toward Sustainable Biofuels.

    Science.gov (United States)

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

    2017-05-09

    To minimize energy consumption and carbon footprints, pervaporation membranes are fast becoming the preferred technology for alcohol recovery. However, this approach is confined to small-scale operations, as the flux of standard rubbery polymer membranes remain insufficient to process large solvent volumes, whereas membrane separations that use glassy polymer membranes are prone to physical aging. This study concerns how the alcohol affinity and intrinsic porosity of networked, organic, microporous polymers can simultaneously reduce physical aging and drastically enhance both flux and selectivity of a super glassy polymer, poly-[1-(trimethylsilyl)propyne] (PTMSP). Slight loss in alcohol transportation channels in PTMSP is compensated by the alcohol affinity of the microporous polymers. Even after continuous exposure to aqueous solutions of alcohols, PTMSP pervaporation membranes loaded with the microporous polymers outperform the state-of-the-art and commercial pervaporation membranes. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  6. Self-assembly of an electronically conductive network through microporous scaffolds.

    Science.gov (United States)

    Sebastian, H Bri; Bryant, Steven L

    2017-06-15

    Electron transfer spanning significant distances through a microporous structure was established via the self-assembly of an electronically conductive iridium oxide nanowire matrix enveloping the pore walls. Microporous formations were simulated using two scaffold materials of varying physical and chemical properties; paraffin wax beads, and agar gel. Following infiltration into the micropores, iridium nanoparticles self-assembled at the pore wall/ethanol interface. Subsequently, cyclic voltammetry was employed to electrochemically crosslink the metal, erecting an interconnected, and electronically conductive metal oxide nanowire matrix. Electrochemical and spectral characterization techniques confirmed the formation of oxide nanowire matrices encompassing lengths of at least 1.6mm, 400× distances previously achieved using iridium nanoparticles. Nanowire matrices were engaged as biofuel cell anodes, where electrons were donated to the nanowires by a glucose oxidizing enzyme. Copyright © 2017 Elsevier Inc. All rights reserved.

  7. Hierarchical mesoporous/microporous carbon with graphitized frameworks for high-performance lithium-ion batteries

    Directory of Open Access Journals (Sweden)

    Yingying Lv

    2014-11-01

    Full Text Available A hierarchical meso-/micro-porous graphitized carbon with uniform mesopores and ordered micropores, graphitized frameworks, and extra-high surface area of ∼2200 m2/g, was successfully synthesized through a simple one-step chemical vapor deposition process. The commercial mesoporous zeolite Y was utilized as a meso-/ micro-porous template, and the small-molecule methane was employed as a carbon precursor. The as-prepared hierarchical meso-/micro-porous carbons have homogeneously distributed mesopores as a host for electrolyte, which facilitate Li+ ions transport to the large-area micropores, resulting a high reversible lithium ion storage of 1000 mA h/g and a high columbic efficiency of 65% at the first cycle.

  8. Sorption of phenanthrene and benzene on differently structural kerogen: important role of micropore-filling.

    Science.gov (United States)

    Zhang, Yulong; Ma, Xiaoxuan; Ran, Yong

    2014-02-01

    Shale was thermally treated to obtain a series of kerogen with varied maturation. Their chemical, structural and porous properties were related to the sorption and/or desorption behaviors of phenanthrene and benzene. As the treatment temperature increases, aliphatic and carbonyl carbon of the kerogen samples decrease, while their aromaticity and maturation increase. Meanwhile, the isothermal nonlinearity of phenanthrene and benzene increases whereas the sorption capacity and micropore adsorption volumes (Vo,d) initially increase and then decrease. The Vo,d of benzene is significantly correlated with, but higher than that of phenanthrene, suggesting similar micropore filling mechanism and molecular sieve effect. The benzene desorption exhibits hysteresis, which is related to the pore deformation of the kerogen and the entrapment of solute in the kerogen matrix. The Vo,d of phenanthrene and benzene on the kerogen samples accounts for 23-46% and 36-65% of the maximum sorption volumes, respectively, displaying the importance of the micropore filling.

  9. Intrinsically Microporous Polymer Membranes for High Performance Gas Separation

    KAUST Repository

    Swaidan, Raja

    2014-11-01

    This dissertation addresses the rational design of intrinsically microporous solutionprocessable polyimides and ladder polymers for highly permeable and highly selective gas transport in cornerstone applications of membrane-based gas separation – that is, air enrichment, hydrogen recovery and natural gas sweetening. By virtue of rigid and contorted chains that pack inefficiently in the solid state, polymers of intrinsic microporosity (PIMs) have the potential to unite the solution-processability, mechanical flexibility and organic tunability of commercially relevant polymers with the microporosity characteristics of porous crystalline materials. The performance enhancements of PIMs over conventional low-free-volume polymers have been primarily permeability-driven, compromising the selectivity essential to commercial viability. An approach to unite high permeability with high selectivity for performance transcending the state-of-the-art in air and hydrogen separations was demonstrated via a fused-ring integration of a three-dimensional, shape persistent triptycene moiety optimally substituted with short, branched isopropyl chains at the 9,10-bridgeheads into a highly inflexible backbone. The resulting polymers exhibited selectivities (i.e., O2/N2, H2/N2, H2/CH4) similar to or higher than commercial materials matched with permeabilities up to three hundred times higher. However, the intra-chain rigidity central to such conventional PIM-design principles was not a singular solution to suppression of CO2-induced plasticization in CO2/CH4 mixedgas separations. Plasticization diminishes the sieving capacity of the membrane, resulting in costly hydrocarbon losses that have significantly limited the commercialization of new polymers. Unexpectedly, the most permeable and selective PIMs designed for air and hydrogen separations strongly plasticized in 50:50 CO2/CH4 mixtures, enduring up to three-fold increases in mixed-gas CH4 permeability by 30 bar and strong drops in

  10. Natural Gas Sweetening by Ultra-Microporous Polyimides Membranes

    KAUST Repository

    Alghunaimi, Fahd

    2017-05-01

    Most natural gas fields in Saudi Arabia contain around 10 mol.% carbon dioxide. The present technology to remove carbon dioxide is performed by chemical absorption, which has many drawbacks. Alternatively, membrane-based gas separation technology has attracted great interest in recent years due to: (i) simple modular design, (ii) potential cost effectiveness, (iii) ease of scale-up, and (iv) environmental friendliness. The state-of-the-art membrane materials for natural gas sweetening are glassy cellulose acetate and polyimide, which were introduced in the 1980s. In the near future, the kingdom is planning to boost its production of natural gas for power generation and increase the feedstock for new petrochemical plants. Therefore, the kingdom and worldwide market has an urgent need for better membrane materials to remove carbon dioxide from raw natural gas. The focus of this dissertation was to design new polyimide membrane materials for CO2/CH4 separation exhibiting high permeability and high selectivity relative to the standard commercial materials tested under realistic mixed-gas feed conditions. Furthermore, this study provided a fundamental understanding of structure/gas transport property relationships of triptycene-based PIM-polyimides. Optimally designed intrinsically microporous polyimide (PIM-PIs) membranes in this work exhibited drastically increased CO2/CH4 selectivities of up to ~75. In addition, a novel triptycene-based hydroxyl-containing polyimide (TDA1-APAF) showed 5-fold higher permeabilities over benchmark commercial materials such as cellulose acetate. Furthermore, this polyimide had a N2/CH4 selectivity of 2.3, thereby making it possible to simultaneously treat CO2- and N2-contaminated natural gas. Also, TDA1-APAF showed a CO2 permeability of 21 Barrer under binary 1:1 CO2/CH4 mixed-gas feed with a selectivity of 72 at a partial CO2 pressure of 10 bar which are significantly better than cellulose triacetate. These results suggest that TDA1

  11. Functional MOF coatings by electrochemical synthesis

    OpenAIRE

    Ameloot, Rob; Stappers, Linda; Fransaer, Jan; Alaerts, Luc; Sels, Bert; De Vos, Dirk

    2008-01-01

    While most efforts in MOF research have been focused on the synthesis and elucidation of new crystal structures, the potential of this new class of microporous solids is clear in areas such as gas storage, molecular separation, catalysis, etc. These applications are generally based on the use of MOFs as bulk powders. In order to fully exploit the potential of these new materials for membranes, sensors and integration with microelectronics, MOF crystals should preferably be grown as patterned ...

  12. Microporous Zeolites as Catalysts for the Preparation of Decyl Glucoside from Glucose with 1-Decanol by Direct Glucosidation

    Directory of Open Access Journals (Sweden)

    Kyong-Hwan Chung

    2016-12-01

    Full Text Available The catalytic properties of microporous zeolite catalysts were evaluated in the synthesis of decyl glucoside from glucose with 1-decanol by direct glucosidation. The effects of the acidic properties and pore structure of the zeolite catalysts on the glucose conversions and decyl glucoside yields were investigated. The conversions of glucose on the H+ ion-exchanged FAU, MFI, and BEA zeolite catalysts were above 70%. The conversion increased with decreasing acid strength of the catalysts. The highest conversion and yield of decyl glucoside were exhibited on the H-FAU(3 zeolite catalyst. The catalytic activities were enhanced with increasing amounts of acid sites. The selectivity of decyl glucopyranoside increased with decreasing Si/Al values for the same zeolite catalysts. The pore structure of H-FAU zeolite would allow sufficient spatial restriction to produce decyl glucopyranoside through the isomerization of decyl glucofuranoside into decyl glucopyranoside in its extensive pore channels. The selectivities of the decyl glucoside isomers relied significantly on the restricted transition state to the primary products due to their pore topologies.

  13. Selective oxidation of benzene and cyclohexane using amorphous microporous mixed oxides; Selektive Oxidation von Benzol und Cyclohexan mit amorphen mikroporoesen Mischoxiden

    Energy Technology Data Exchange (ETDEWEB)

    Stoeckmann, M.

    2000-07-01

    Phenol was to be produced by direct oxidation of benzene with environment-friendly oxidants like hydrogen peroxide, oxygen, or ozone. Catalysts were amorphous microporous mixed oxides whose properties can be selected directly in the sol-gel synthesis process. Apart from benzene, also cyclohexane was oxidized with ozone using AMM catalysts in order to get more information on the potential of ozone as oxidant in heterogeneously catalyzed reactions. [German] Ziel dieser Arbeit war die Herstellung von Phenol durch die Direktoxidation von Benzol mit umweltfreundlichen Oxidationsmitteln wie Wasserstoffperoxid, Sauerstoff oder Ozon. Als Katalysatoren dienten amorphe mikroporoese Mischoxide, da deren Eigenschaften direkt in der Synthese durch den Sol-Gel-Prozess gezielt eingestellt werden koennen. Neben Benzol wurde auch Cyclohexan mit Ozon unter der Verwendung von AMM-Katalysatoren oxidiert, um das Potential von Ozon als Oxiationsmittel in heterogen katalysierten Reaktionen naeher zu untersuchen. (orig.)

  14. Influence of microwave radiation on the growth of gold nanoparticles and microporous zincophosphates in a reverse micellar system.

    Science.gov (United States)

    Doolittle, John W; Dutta, Prabir K

    2006-05-09

    The water core of reverse micelles has been extensively used as the site for synthesis of a variety of materials. However, water-in-oil reverse micelles have a limited range of temperatures over which they are stable as a single phase. Directing heat to the water cores, the usual site of synthesis without heating the bulk provides added opportunities for synthesis. Microwave radiation is a method for superheating the water cores. In this study, we use an H2O-sodium bis(2-ethylhexyl) sulfosuccinate (AOT)-heptane reverse micelle system for the synthesis of Au particles by hydrazine reduction of HAuCl4 in the presence and absence of microwave radiation. The duration of the microwave radiation was limited to a 2-min duration at a power of 300 W, thereby ensuring that the reverse micelle phase is maintained during the synthesis. At all hydrazine concentrations studied (0.5-2 M), the presence of microwave radiation led to an increase in the particle size of Au. The second system examined was the growth of microporous zincophosphate-X (ZnPO-X, an analogue of the faujasite structure) synthesized from H2O-dioctyldimethylammonium chloride (DODMAC)-heptane reverse micelle system. Microwave radiation was applied for 1 min at 150 W at various stages of the nucleation and growth process, and did not disrupt the reverse micelle system. Product analysis after 48 h of reaction showed that the 1-min microwave pulse, if applied during the nucleation stage (the first 4 h), promoted the formation of NaZnPO4.H2O over ZnPO-X. The effect of the microwave pulse at the growth stage was to promote the formation of ZnPO-X. Absorption of the microwave radiation by the water core and surrounding polar surfactant molecules leads to a rapid rise in local temperature (predicted to be approximately 150 degrees C/min for the AOT system), increasing the rates of intramicellar reactions.

  15. PLASMA POLYMERIZATION OF HYDROPHILIC AND HYDROPHOBIC MONOMERS FOR SURFACE MODIFICATION OF NUCLE-MICROPOROUS MEMBRANE

    Institute of Scientific and Technical Information of China (English)

    LI Xuefen; LI Zhifen; CHEN Chuanfu; WU Wenhui

    1990-01-01

    Surface modification of nucle-microporous membrane by plasma polymerization of HEMA, NVP and D4 has been studied. The hydrophilicity of membranes was increased with increasing of plasma polymerization time of hydrophilic monomers HEMA and NVP. The flow rate of water through the membrane was increased remarkably after plasma polymerization of HEMA on it.

  16. Unidirectional Fast Growth and Forced Jumping of Stretched Droplets on Nanostructured Microporous Surfaces.

    Science.gov (United States)

    Aili, Abulimiti; Li, Hongxia; Alhosani, Mohamed H; Zhang, TieJun

    2016-08-24

    Superhydrophobic nanostructured surfaces have demonstrated outstanding capability in energy and water applications by promoting dropwise condensation, where fast droplet growth and efficient condensate removal are two key parameters. However, these parameters remain contradictory. Although efficient droplet removal is easily obtained through coalescence jumping on uniform superhydrophobic surfaces, simultaneously achieving fast droplet growth is still challenging. Also, on such surfaces droplets can grow to larger sizes without restriction if there is no coalescence. In this work, we show that superhydrophobic nanostructured microporous surfaces can manipulate the droplet growth and jumping. Microporous surface morphology effectively enhances the growth of droplets in pores owing to large solid-liquid contact area. At low supersaturations, the upward growth rate (1-1.5 μm/s) of these droplets in pores is observed to be around 15-25 times that of the droplets outside the pores. Meanwhile, their top curvature radius increases relatively slowly (∼0.25 μm/s) due to pore confinement, which results in a highly stretched droplet surface. We also observed forced jumping of stretched droplets in pores either through coalescence with spherical droplets outside pores or through self-pulling without coalescence. Both experimental observation and theoretical modeling reveal that excess surface free energy stored in the stretched droplet surface and micropore confinement are responsible for this pore-scale-forced jumping. These findings reveal the insightful physics of stretched droplet dynamics and offer guidelines for the design and fabrication of novel super-repellent surfaces with microporous morphology.

  17. Microporous silica and doped silica membrane for alcohol dehydration by pervaporation

    NARCIS (Netherlands)

    Sekulic, J.; Luiten, M.W.J.; Elshof, ten J.E.; Benes, N.E.; Keizer, K.

    2002-01-01

    The aim of this work is the development of inorganic membranes that will enable broad application of pervaporation/vapour permeation technology in the chemical industry. This can be achieved by improvement of the existing microporous membranes and the development of new types with enhanced thermoche

  18. Selective capture of water using microporous adsorbents to increase the lifetime of lubricants.

    Science.gov (United States)

    Ng, Eng-Poh; Delmotte, Luc; Mintova, Svetlana

    2009-01-01

    Long live lubricants: The selective capture of water from lubricants using nanosized microporous aluminophosphate (AEI) and aluminosilicate materials was studied. Nearly 98 % of the moisture was removed from the lubricating oil under ambient conditions, resulting in a significant improvement in the lubricating service lifetime. Moreover, both the lubricant and the microporous sorbents can be recovered and reused.The selective capture of water from lubricants using nanosized microporous aluminophosphate and aluminosilicate materials was studied with an aim to increase the lifetime of the lubricating mineral oil. The amount of water present in oxidized lubricating oil before and after treatment with microporous materials was studied by FTIR spectroscopy and determined quantitatively using the Karl Fischer titration method. Nanosized aluminophosphate revealed a high selectivity for water without adsorbing other additives, in contrast to nanosized aluminosilicates which also adsorb polar oxidation products and ionic additives. About 98 % of the initial moisture could be removed from the lubricating oil under ambient conditions, resulting in a significant improvement in the lubricating service lifetime. Moreover, no by-products are formed during the process and both the lubricant and the sorbents can be recovered and reused, thus the method is environmentally friendly.

  19. Redox-active conjugated microporous polymers: a new organic platform for highly efficient energy storage.

    Science.gov (United States)

    Xu, Fei; Chen, Xiong; Tang, Zhiwei; Wu, Dingcai; Fu, Ruowen; Jiang, Donglin

    2014-05-14

    Conjugated microporous polymers are developed as a new platform for lithium-battery energy storage, which features a near-unity coulombic efficiency, high capacity and cycle stability. The polymers exhibit synergistic structural effects on facilitating charge dynamics by virtue of their built-in redox skeletons, open nanopores and large surface areas.

  20. Super absorbent conjugated microporous polymers: a synergistic structural effect on the exceptional uptake of amines.

    Science.gov (United States)

    Liu, Xiaoming; Xu, Yanhong; Guo, Zhaoqi; Nagai, Atsushi; Jiang, Donglin

    2013-04-21

    Conjugated microporous polymers exhibit a synergistic structural effect on the exceptional uptake of amines, whereas the dense porphyrin units facilitate uptake, the high porosity offers a large interface and the swellability boosts capacity. They are efficient in the uptake of both vapor and liquid amines, are applicable to various types of amines, and are excellent for cycle use.

  1. Evaluation of procedures for estimation of the isosteric heat of adsorption in microporous materials

    NARCIS (Netherlands)

    Krishna, R.

    2014-01-01

    The major objective of this communication is to evaluate procedures for estn. of the isosteric heat of adsorption, Qst, in microporous materials such as zeolites, metal org. frameworks (MOFs)​, and zeolitic imidazolate frameworks (ZIFs)​. For this purpose we have carefully analyzed published exptl.

  2. Size and spacial distribution of micropores in SBA-15 using CM-SANS

    Energy Technology Data Exchange (ETDEWEB)

    Pollock, Rachel A [ORNL; Walsh, Brenna R [ORNL; Fry, Jason A [ORNL; Ghampson, Tyrone [University of Maine; Centikol, Ozgul [Joint Bioenergy Institute; Melnichenko, Yuri B [ORNL; Kaiser, Helmut [ORNL; Pynn, Roger [ORNL; Frederick, Brian G [ORNL

    2011-01-01

    Diffraction intensity analysis of small-angle neutron scattering measurements of dry SBA-15 have been combined with nonlocal density functional theory (NLDFT) analysis of nitrogen desorption isotherms to characterize the micropore, secondary mesopore, and primary mesopore structure. The radial dependence of the scattering length density, which is sensitive to isolated surface hydroxyls, can only be modeled if the NLDFT pore size distribution is distributed relatively uniformly throughout the silica framework, not localized in a 'corona' around the primary mesopores. Contrast matching-small angle neutron scattering (CM-SANS) measurements, using water, decane, tributylamine, cyclohexane, and isooctane as direct probes of the size of micropores indicate that the smallest pores in SBA-15 have diameter between 5.7 and 6.2 {angstrom}. Correlation of the minimum pore size with the onset of the micropore size distribution provides direct evidence that the shape of the smallest micropores is cylinderlike, which is consistent with their being due to unraveling of the polymer template.

  3. Massive preparation of pitch-based organic microporous polymers for gas storage.

    Science.gov (United States)

    Li, Wenqing; Zhang, Aijuan; Gao, Hui; Chen, Mingjie; Liu, Anhua; Bai, Hua; Li, Lei

    2016-02-14

    A general challenge for preparing organic microporous polymers (MOPs) is to use cheap and sustainable building blocks while retaining the advanced functions. We demonstrate a strategy to massively prepare pitch-based MOPs, which are thermally and chemically stable. A maximum BET surface area of 758 m(2) g(-1) and high gas storage capacity were achieved.

  4. A sixfold interpenetrated microporous MOF constructed from heterometallic tetranuclear cluster exhibiting selective gas adsorption.

    Science.gov (United States)

    Li, Yun-Wu; Wang, Li-Fu; He, Kun-Huan; Chen, Qiang; Bu, Xian-He

    2011-10-28

    A sixfold interpenetrated microporous MOF has been constructed from a heterometallic tetranuclear cluster. The framework contains two types of 1D micro-channels along different directions. Moreover, this compound exhibits high selective gas sorption for H(2) over N(2).

  5. Describing mixture diffusion in microporous materials under conditions of pore saturation

    NARCIS (Netherlands)

    Krishna, R.; van Baten, J.M.

    2010-01-01

    In a variety of practical applications involving microporous materials such as zeolites and metal organic frameworks (MOFs), the operating conditions are such that the concentration of guest molecules within the pore space approaches saturation conditions. This situation arises, for example, in CO2

  6. Quasi-elastic neutron scattering study of the mobility of methane in microporous silica

    NARCIS (Netherlands)

    Benes, Nieck E.; Jobic, Herve; Verweij, Henk

    2001-01-01

    The dynamics of translation and rotation of methane in microporous bulk silica have been studied with quasi-elastic neutron scattering. At T=200 K the self-diffusion coefficient of translation is DS=1.1×10−8 m2 s−1 with an estimated activation energy of 4 kJ mol−1. Any variation of DS with occupanc

  7. Modelling the effect of wettability distributions on oil recovery from microporous carbonate reservoirs

    Science.gov (United States)

    Kallel, W.; van Dijke, M. I. J.; Sorbie, K. S.; Wood, R.; Jiang, Z.; Harland, S.

    2016-09-01

    Carbonate-hosted hydrocarbon reservoirs are known to be weakly- to moderately oil-wet, but the pore-scale wettability distribution is poorly understood. Moreover, micropores, which often dominate in carbonate reservoirs, are usually assumed to be water-wet and their role in multi-phase flow is neglected. Modelling the wettability of carbonates using pore network models is challenging, because of our inability to attribute appropriate chemical characteristics to the pore surfaces and over-simplification of the pore shapes. Here, we implement a qualitatively plausible wettability alteration scenario in a two-phase flow network model that captures a diversity of pore shapes. The model qualitatively reproduces patterns of wettability alteration recently observed in microporous carbonates via high-resolution imaging. To assess the combined importance of pore-space structure and wettability on petrophysical properties, we consider a homogeneous Berea sandstone network and a heterogeneous microporous carbonate network, whose disconnected coarse-scale pores are connected through a sub-network of fine-scale pores. Results demonstrate that wettability effects are significantly more profound in the carbonate network, as the wettability state of the micropores controls the oil recovery.

  8. The function of microporous layers and the interaction between the anode and cathode in DMFCs

    DEFF Research Database (Denmark)

    Zhang, H. F.; Wang, SY; Pei, PC

    2008-01-01

    A combined effect of microporous layers (MPLs) on direct methanol fuel cells (DMFCs) is investigated. From the distribution of the outstanding carbon loading combinations of the cathode MPL and anode MPL as well as the evolutions of polarization curves, a combined effect in which the contribution...

  9. Preparation and Haemocompatibility of Regular Array Microporous PLGA Films on Stainless Steel Surface

    Institute of Scientific and Technical Information of China (English)

    2005-01-01

    Regular array microporous films from poly ( L-lactic-co-glycolic acid) ( PLGA ) were prepared on stainless steel substrates utilizing the condensation of water droplets on polymer solutions. The size of the pores and regularity can be controlled by atmospheric humidity and concentration of polymer solution. The microporons films have strong hydrophobicity and good haemocompatibility.

  10. Hydrothermal Synthesis and Characterization of a Metal-Organic Framework by Thermogravimetric Analysis, Powder X-Ray Diffraction, and Infrared Spectroscopy: An Integrative Inorganic Chemistry Experiment

    Science.gov (United States)

    Crane, Johanna L.; Anderson, Kelly E.; Conway, Samantha G.

    2015-01-01

    This advanced undergraduate laboratory experiment involves the synthesis and characterization of a metal-organic framework with microporous channels that are held intact via hydrogen bonding of the coordinated water molecules. The hydrothermal synthesis of Co[subscript 3](BTC)[subscript 2]·12H[subscript 2]O (BTC = 1,3,5-benzene tricarboxylic acid)…

  11. Hydrothermal Synthesis and Characterization of a Metal-Organic Framework by Thermogravimetric Analysis, Powder X-Ray Diffraction, and Infrared Spectroscopy: An Integrative Inorganic Chemistry Experiment

    Science.gov (United States)

    Crane, Johanna L.; Anderson, Kelly E.; Conway, Samantha G.

    2015-01-01

    This advanced undergraduate laboratory experiment involves the synthesis and characterization of a metal-organic framework with microporous channels that are held intact via hydrogen bonding of the coordinated water molecules. The hydrothermal synthesis of Co[subscript 3](BTC)[subscript 2]·12H[subscript 2]O (BTC = 1,3,5-benzene tricarboxylic acid)…

  12. Pool boiling characteristics and critical heat flux mechanisms of microporous surfaces and enhancement through structural modification

    Science.gov (United States)

    Ha, Minseok; Graham, Samuel

    2017-08-01

    Experimental studies have shown that microporous surfaces induce one of the highest enhancements in critical heat flux (CHF) during pool boiling. However, microporous surfaces may also induce a very large surface superheat (>100 °C) which is not desirable for applications such as microelectronics cooling. While the understanding of the CHF mechanism is the key to enhancing boiling heat transfer, a comprehensive understanding is not yet available. So far, three different theories for the CHF of microporous surfaces have been suggested: viscous-capillary model, hydrodynamic instability model, and dryout of the porous coatings. In general, all three theories account for some aspects of boiling phenomena. In this study, the theories are examined through their correlations with experimental data on microporous surfaces during pool boiling using deionized (DI) water. It was found that the modulation of the vapor-jet through the pore network enables a higher CHF than that of a flat surface based on the hydrodynamic instability theory. In addition, it was found that as the heat flux increases, a vapor layer grows in the porous coatings described by a simple thermal resistance model which is responsible for the large surface superheat. Once the vapor layer grows to fill the microporous structure, transition to film boiling occurs and CHF is reached. By disrupting the formation of this vapor layer through the fabrication of channels to allow vapor escape, an enhancement in the CHF and heat transfer coefficient was observed, allowing CHF greater than 3500 kW/m2 at a superheat less than 50 °C.

  13. A polystyrene-based microfluidic device with three-dimensional interconnected microporous walls for perfusion cell culture

    Science.gov (United States)

    Chan, Chung Yu; Goral, Vasiliy N.; DeRosa, Michael E.; Huang, Tony Jun

    2014-01-01

    In this article, we present a simple, rapid prototyped polystyrene-based microfluidic device with three-dimensional (3D) interconnected microporous walls for long term perfusion cell culture. Patterned 3D interconnected microporous structures were created by a chemical treatment together with a protective mask and the native hydrophobic nature of the microporous structures were selectively made hydrophilic using oxygen plasma treatment together with a protective mask. Using this polystyrene-based cell culture microfluidic device, we successfully demonstrated the support of four days perfusion cell culture of hepatocytes (C3A cells). PMID:25379110

  14. Synthesis of a new meso/microporous composite molecular sieve of MCM-41/mordenite

    Institute of Scientific and Technical Information of China (English)

    WANG Shan; DOU Tao; LI Yuping; ZHANG Ying; YAN Zichun; LI Xiaofeng

    2005-01-01

    An MCM-41/mordenite composite with twofold porous structure and stepwise-distributed acidity was prepared for the first time by using zeolite mordenite as the silica-alumina source. The composite molecular sieve has been investigated and compared with a mechanical mixture of mordenite and MCM-41 for their structure, acidity and catalytic activity by means of XRD, N2 adsorption and desorption, HRTEM, DTG, NH3-TPD and catalytic reaction. The characterization results show that the structure and property of the composite molecular sieve are quite different from those of the mechanical mixture, which might be ascribed to the incorporation of secondary building units characteristic of zeolite mordenite into the mesoporous walls of the composite which gives rise to the thicker mesoporous walls, the higher hydrothermal stability and more strong acid sites. Furthermore, the new strategy could be used as a new general method for the preparation of catalysts for the reaction system with multifold large molecules, and the results were well confirmed by the dealkylation of C10+ aromatic hydrocarbon.

  15. Biological function evaluation and effects of laser micro-pore burn-denatured acellular dermal matrix.

    Science.gov (United States)

    Zhang, Youlai; Zeng, Yuanlin; Xin, Guohua; Zou, Lijin; Ding, Yuewei; Duyin, Jiang

    2017-08-18

    In the field of burns repairs, many problems exist in the shortage of donor skin, the expense of allograft or xenograft skin, temporary substitution and unsatisfactory extremity function after wound healing. Previous studies showed that burn-denatured skin could return to normal dermis formation and function. This study investigates the application of laser micro-pore burn-denatured acellular dermis matrix (DADM) from an escharotomy in the repair of burn wounds and evaluates the biological properties and wound repair effects of DADM in implantation experiments in Kunming mice. Specific-pathogen-free (SPF) Kunming mice were used in this study. A deep II° burn wound was created on the dorsum of the mice by an electric heated water bath. The full-thickness wound tissue was harvested. The necrotic tissue and subcutaneous tissue were removed. The denatured dermis was preserved and treated with 0.25% trypsin, 0.5% Triton X-100. The DADM was drilled by laser micro-pore. The biological properties and grafting effects of laser micro-pore burn-DADM were evaluated by morphology, cytokine expression levels and subcutaneous implantation experiments in Kunming mice. We found statistical significance (Plaser micro-pore burn-DADM (experimental group) compared to the control group (no laser micro-pore burn-DADM). Cytokine expression level was different in the dermal matrixes harvested at various time points after burn (24h, 48h, 72h and infected wound group). Comparing the dermal matrix from 24h burn tissue to infected wound tissue, the expression level of IL-6, MMP-24, VE-cadherin and VEGF were decreased. We found no inflammatory cells infiltration in the dermal matrix were observed in both experimental and control groups (24h burn group), while the obviously vascular infiltration and fiber fusion were observed in the experimental group after subcutaneous implantation experiments. There was better bio-performance, low immunogenicity and better dermal incorporation after treated

  16. THERMODYNAMIC STUDY OF HIGH-PRESSURE ADSORPTION OF METHANE AND HEATS OF METHANE ADSORPTION ON MICROPOROUS CARBONS

    Institute of Scientific and Technical Information of China (English)

    杨晓东; 林文胜; 郑青榕; 顾安忠; 鲁雪生; 宋燕

    2002-01-01

    The study was done for high-pressure adsorption of methane on microporous carbons, which has an ANG vehicular application background. Adsorption isotherm of methane on super activated carbon up to 6 MPa was measured and isosteric heats of methane adsorption on a number of microporous carbons were determined from adsorption isosteres by the Clausius-Clapeyron equation. The variation of the isosteric heats of adsorption with the amount of methane adsorbed was discussed.

  17. Direct determination of intermolecular structure of ethanol adsorbed in micropores using X-ray diffraction and reverse Monte Carlo analysis

    OpenAIRE

    Iiyama, Taku; Hagi, Kousuke; Urushibara, Takafumi; Ozeki, Sumio

    2009-01-01

    The intermolecular structure of C(2)H(5)OH molecules confined in slit-shaped graphitic micropore of activated carbon fiber was investigated by in situ X-ray diffraction (XRD) measurement and reverse Monte Carlo (RMC) analysis. The pseudo-3-dimensional intermolecular structure Of C(2)H(5)OH adsorbed in the micropores was determined by applying the RMC analysis to XRD data, assuming a simple slit-shaped space composed of double graphene sheets. The results were consistent with conventional Mont...

  18. Structural study and fluorescent property of a novel organic microporous crystalline material

    Energy Technology Data Exchange (ETDEWEB)

    Cheng, Zhao; Yang, Bingqin; Yang, Meipan; Zhang, Binglin, E-mail: yangbq@nwu.edu.cn [Key Laboratory of Synthetic and Natural Functional Molecule Chemistry of Ministry of Education, College of Chemistry and Materials Science, Northwest University (China)

    2014-01-15

    A novel microporous organic material [(2-{2-[2-(bis-methoxycarbonylmethylamino)phenoxy] ethoxy}-4-benzimidazole-phenyl)methoxycarbonylmethylamino]acetic acid methyl ester 6 was synthesized and characterized by single crystal X-ray diffraction, Fourier transform infrared spectroscopy (FT-IR), electron spray ionization-mass spectrometry (ESI-HRMS), X-ray powder diffraction (PXRD), {sup 1}H and {sup 13}C NMR. 6 crystallizes in the centrosymmetric monoclinic space group C2/c, with unit cell parameters a = 35.648(3) Å, b = 14.3240(12) Å, c = 15.3693(13) Å, a = 90.00, ß = 94.8190(10), γ = 90.00, V = 7820.16 Å{sup 3} and Z = 8 at 296(2) K. As indicated by crystal packing, the molecular conjugation planes arrange along the c axis to form micropores due to the hydrogen bonds. In addition, the fluorescent spectrum and luminescence lifetime were studied for 6. (author)

  19. esearch and Application of Burned Microporous High Alumian—Graphite(Al/C) Brick in Blast Furnace

    Institute of Scientific and Technical Information of China (English)

    ZHANXiaoming; SONGMusen

    1999-01-01

    This paper inroduces the research background,technology,product property and application of burned microporous high alumina-graphite brick (Al2O3-C brick) used in blast furnace,The difference of property between Al2O3-C brick and other blast furnace refractories is discussed .The results of simulative tests show that ,Al2O3-C brick has good alkali resistance,slag resistance,thermal shock resistance,oxidation resistance,high thermal conductivity,low permeability and low solubility in molten iron,The brick with micropores of average radius less than 1μm has been successively applied to fourteen blast furnaces, the lining life of the brick is almost as long as that of Si3N4 bonded SiC brick Al2O3-C brick will be widely used in lower stack ,belly,bosh and hearth in the future.

  20. Microporous carbon nanosheets with redox-active heteroatoms for pseudocapacitive charge storage

    Science.gov (United States)

    Yun, Y. S.; Kim, D.-H.; Hong, S. J.; Park, M. H.; Park, Y. W.; Kim, B. H.; Jin, H.-J.; Kang, K.

    2015-09-01

    We report microporous carbon nanosheets containing numerous redox active heteroatoms fabricated from exfoliated waste coffee grounds by simple heating with KOH for pseudocapacitive charge storage. We found that various heteroatom combinations in carbonaceous materials can be a redox host for lithium ion storage. The bio-inspired nanomaterials had unique characteristics, showing superior electrochemical performances as cathode for asymmetric pseudocapacitors.We report microporous carbon nanosheets containing numerous redox active heteroatoms fabricated from exfoliated waste coffee grounds by simple heating with KOH for pseudocapacitive charge storage. We found that various heteroatom combinations in carbonaceous materials can be a redox host for lithium ion storage. The bio-inspired nanomaterials had unique characteristics, showing superior electrochemical performances as cathode for asymmetric pseudocapacitors. Electronic supplementary information (ESI) available. See DOI: 10.1039/c5nr04231c

  1. Microporous La-metal-organic framework (MOF) with large surface area.

    Science.gov (United States)

    Pal, Souvik; Bhunia, Asamanjoy; Jana, Partha P; Dey, Subarna; Möllmer, Jens; Janiak, Christoph; Nayek, Hari Pada

    2015-02-09

    A microporous La-metal-organic framework (MOF) has been synthesized by the reaction of La(NO3 )3 ⋅6 H2 O with a ligand 4,4',4''-s-triazine-1,3,5-triyltri-p-aminobenzoate (TATAB) featuring three carboxylate groups. Crystal structure analysis confirms the formation of 3D MOF with hexagonal micropores, a Brunauer-Emmett-Teller (BET) surface area of 1074 m(2)  g(-1) and high thermal and chemical stability. The CO2 adsorption capacities are 76.8 cm(3)  g(-1) at 273 K and 34.6 cm(3)  g(-1) at 293 K, a highest measured CO2 uptake for a Ln-MOFs. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  2. SURFACE MODIFICATION OF POLYPROPYLENE MICROPOROUS MEMBRANES BY THE ADSORPTION OF NON-IONIC SURFACTANTS

    Institute of Scientific and Technical Information of China (English)

    Ya-jie Xie; Hai-yin Yu; Zhi-kang Xu

    2006-01-01

    Surface modification by physical adsorption of a series of non-ionic surfactants including Tween 20, Tween 40,Tween 60, Tween 80 and Tween 85, was accomplished on polypropylene microporous hollow fiber and flat membranes. The adsorption curve of the membrane surface was analyzed by weight measurements and the typical results showed a twoplatform character similarly. Differences in the degree and curve shape of adsorption resulting from such factors as concentration, temperature, as well as water cleaning time were observed for Tween 85 among other Tweens. Attenuated total reflection - Fourier transform infrared spectroscopy analysis and field emission scanning electron microscopy observation showed that the adsorption of Tween on polypropylene microporous membrane (PPMM) is effective and occurs mainly in the pores of PPMMs at low adsorption amount, and on the membrane surface also at high adsorption value.

  3. Preparation and characterization of a novel composite microporous polymer electrolyte for Li-ion batteries

    Institute of Scientific and Technical Information of China (English)

    CHEN Zuofeng; JIANG Yanxia; ZHUANG Quanchao; DONG Quanfeng; WANG Ye; SUN Shigang

    2005-01-01

    A novel composite microporous polymer electrolyte composed of poly(vinylidene fluoride-co-hexafluorop- ropylene) (PVdF-HFP) and mesoporous SBA-15 was prepared. The composite solid polymer electrolyte (CSPE) exhibits ionic conductivity as high as 0.30 mS·cm-1 with a composition of SBA-15:PVdF-HFP=3:8 at room temperature. Infrared transmission spectroscopic results suggested that the mechanism of micropore formation is similar to that of the phase inversion. X-ray diffraction (XRD) results demonstrated that the addition of SBA-15 inhibits the crystallization of PVdF-HFP, while the SBA-15 preserves well its ordered mesoporous structure during the course of preparation. The Li/CSPE/MCF of half-cell was assembled, and it showed a good electrochemical and cyclability performance during charge-discharge cycles.

  4. Efficient fixation of CO2 at mild conditions by a Cr-conjugated microporous polymer

    Institute of Scientific and Technical Information of China (English)

    Yong; Xie; Rui-Xia; Yang; Nian-Yu; Huang; Hua-Jun; Luo; Wei-Qiao; Deng

    2014-01-01

    We reported a bifunctional material, Cr-salen implanted conjugated microporous polymer(Cr-CMP), which is able to capture excellent CO2amounts and has a remarkable catalytic activity towards the cycloaddition reaction of CO2to epoxides forming cyclic carbonates at mild conditions without additional solvents. This heterogeneous Cr-CMP catalyst has a superior catalytic activity to its related homogeneous catalyst and can be reused more than ten times without a significant decrease in catalytic activity.

  5. Mobility of hydrogen in microporous silica studied with quasi-elastic neutron scattering

    NARCIS (Netherlands)

    Benes, Nieck E.; Jobic, Herve; Reat, Valerie; Bouwmeester, Henny J.M.; Verweij, Henk

    2003-01-01

    The mobility of H2 in microporous amorphous silica is studied using quasi-elastic neutron scattering. At T=90 K the self-diffusion coefficient is approximately Ds=1.2×10−8 m2 s−1 for low degrees of occupancy (<20%) and decreases slightly to Ds=0.95×10−8 m2 s−1 for an occupancy of 31%. A rough esti

  6. Mathematical modeling of wastewater treatment from multicomponent pollution by through microporous filling

    Science.gov (United States)

    Bomba, A.; Klymiuk, Yu.; Prysiazhniuk, I.; Prysiazhniuk, O.; Safonyk, A.

    2016-10-01

    The nonlinear singularly perturbed convection-diffusion process of the adsorption mass transfer in multicomponent multilayer filter pollution, each layer of which consists of particles of microporous structure is modeled. We construct the asymptotic expansion resolving relevant model boundary problem and on this basis conduct numerical experiment that allows to evaluate the impact of the various components of the process for the distribution of contaminants in the filter.

  7. Electroless plating of thin gold films directly onto silicon nitride thin films and into micropores.

    Science.gov (United States)

    Whelan, Julie C; Karawdeniya, Buddini Iroshika; Bandara, Y M Nuwan D Y; Velleco, Brian D; Masterson, Caitlin M; Dwyer, Jason R

    2014-07-23

    A method to directly electrolessly plate silicon-rich silicon nitride with thin gold films was developed and characterized. Films with thicknesses plating free-standing ultrathin silicon nitride membranes, and we successfully plated the interior walls of micropore arrays in 200 nm thick silicon nitride membranes. The method is thus amenable to coating planar, curved, and line-of-sight-obscured silicon nitride surfaces.

  8. Electrochemical route to fabricate film-like conjugated microporous polymers and application for organic electronics.

    Science.gov (United States)

    Gu, Cheng; Chen, Youchun; Zhang, Zhongbo; Xue, Shanfeng; Sun, Shuheng; Zhang, Kai; Zhong, Chengmei; Zhang, Huanhuan; Pan, Yuyu; Lv, Ying; Yang, Yanqin; Li, Fenghong; Zhang, Suobo; Huang, Fei; Ma, Yuguang

    2013-07-05

    Film-like conjugated microporous polymers (CMPs) are fabricated by the novel strategy of carbazole-based electropolymerization. The CMP film storing a mass of counterions acting as an anode interlayer provides a significant power-conversion efficiency of 7.56% in polymer solar cells and 20.7 cd A(-1) in polymer light-emitting diodes, demonstrating its universality and potential as an electrode interlayer in organic electronics.

  9. Fluorinated microporous organic polymers: design and applications in CO₂ adsorption and conversion.

    Science.gov (United States)

    Yang, Zhen-Zhen; Zhao, Yanfei; Zhang, Hongye; Yu, Bo; Ma, Zhishuang; Ji, Guipeng; Liu, Zhimin

    2014-11-21

    Fluorinated microporous organic polymers (F-MOPs) were designed, showing twice higher CO2 adsorption capacity than corresponding non-fluorous MOPs. The incorporation of phenanthroline moieties into F-MOPs afforded them the ability to coordinate with Ag(I), and the resultant F-MOP-Ag(I) displayed high efficiency for the reaction of CO2 with propargyl alcohols to form α-alkylidene cyclic carbonates at 25 °C.

  10. Adsorption of pharmaceuticals to microporous activated carbon treated with potassium hydroxide, carbon dioxide, and steam.

    Science.gov (United States)

    Fu, Heyun; Yang, Liuyan; Wan, Yuqiu; Xu, Zhaoyi; Zhu, Dongqiang

    2011-01-01

    Adsorption of sulfapyridine, tetracycline, and tylosin to a commercial microporous activated carbon (AC) and its potassium hydroxide (KOH)-, CO-, and steam-treated counterparts (prepared by heating at 850°C) was studied to explore efficient adsorbents for the removal of selected pharmaceuticals from water. Phenol and nitrobenzene were included as additional adsorbates, and nonporous graphite was included as a model adsorbent. The activation treatments markedly increased the specific surface area and enlarged the pore sizes of the mesopores of AC (with the strongest effects shown on the KOH-treated AC). Adsorption of large-size tetracycline and tylosin was greatly enhanced, especially for the KOH-treated AC (more than one order of magnitude), probably due to the alleviated size-exclusion effect. However, the treatments had little effect on adsorption of low-size phenol and nitrobenzene due to the predominance of micropore-filling effect in adsorption and the nearly unaffected content of small micropores causative to such effect. These hypothesized mechanisms on pore-size dependent adsorption were further tested by comparing surface area-normalized adsorption data and adsorbent pore size distributions with and without the presence of adsorbed antibiotics. The findings indicate that efficient adsorption of bulky pharmaceuticals to AC can be achieved by enlarging the adsorbent pore size through suitable activation treatments.

  11. A thermodynamic analysis of gas adsorption on microporous materials: evaluation of energy heterogeneity.

    Science.gov (United States)

    Llorens, Joan; Pera-Titus, Marc

    2009-03-15

    This paper presents a thermodynamic isotherm derived from solution thermodynamics principles to describe gas adsorption on microporous materials. This isotherm relies on a potential relationship between the integral free energy of adsorption relative to saturation, Psi/RT, expressed by the Kiselev equation, and the variable Z = 1/-Ln(Pi), being Pi the relative pressure. A mathematical analysis reveals that the adsorption energy heterogeneity in the micropores is collected in a characteristic parameter of the isotherm, m, that can be related to the alpha parameter of the Dubinin-Astakhov isotherm in a simple way (m = alpha + 1). The isotherm also predicts a plateau in Psi/RT at extremely low pressures (Pi < 10(-7)). Neimark's thermodynamic equation accounting for gas adsorption on mesoporous solids is found to be a particular case of the isotherm presented in this study. The Langmuir isotherm only shows consistency with the thermodynamic isotherm for a reduced combination of values of the relevant parameters, not usually found in common adsorbents. The suitability of the thermodynamic isotherm is experimentally assessed by testing a collection of microporous materials, including activated carbons, carbon nanotubes, and zeolites.

  12. Fabrication of high-transmission microporous membranes by proton beam writing-based molding technique

    Science.gov (United States)

    Wang, Liping; Meyer, Clemens; Guibert, Edouard; Homsy, Alexandra; Whitlow, Harry J.

    2017-08-01

    Porous membranes are widely used as filters in a broad range of micro and nanofluidic applications, e.g. organelle sorters, permeable cell growth substrates, and plasma filtration. Conventional silicon fabrication approaches are not suitable for microporous membranes due to the low mechanical stability of thin film substrates. Other techniques like ion track etching are limited to the production of randomly distributed and randomly orientated pores with non-uniform pore sizes. In this project, we developed a procedure for fabricating high-transmission microporous membranes by proton beam writing (PBW) with a combination of spin-casting and soft lithography. In this approach, focused 2 MeV protons were used to lithographically write patterns consisting of hexagonal arrays of high-density pillars of few μm size in a SU-8 layer coated on a silicon wafer. After development, the pillars were conformably coated with a thin film of poly-para-xylylene (Parylene)-C release agent and spin-coated with polydimethylsiloxane (PDMS). To facilitate demolding, a special technique based on the use of a laser-cut sealing tape ring was developed. This method facilitated the successful delamination of 20-μm thick PDMS membrane with high-density micropores from the mold without rupture or damage.

  13. Capture and conversion of CO2 at ambient conditions by a conjugated microporous polymer.

    Science.gov (United States)

    Xie, Yong; Wang, Ting-Ting; Liu, Xiao-Huan; Zou, Kun; Deng, Wei-Qiao

    2013-01-01

    Conjugated microporous polymers are a new class of porous materials with an extended π-conjugation in an amorphous organic framework. Owing to the wide-ranging flexibility in the choice and design of components and the available control of pore parameters, these polymers can be tailored for use in various applications, such as gas storage, electronics and catalysis. Here we report a class of cobalt/aluminium-coordinated conjugated microporous polymers that exhibit outstanding CO2 capture and conversion performance at atmospheric pressure and room temperature. These polymers can store CO2 with adsorption capacities comparable to metal-organic frameworks. The cobalt-coordinated conjugated microporous polymers can also simultaneously function as heterogeneous catalysts for the reaction of CO2 and propylene oxide at atmospheric pressure and room temperature, wherein the polymers demonstrate better efficiency than a homogeneous salen-cobalt catalyst. By combining the functions of gas storage and catalysts, this strategy provides a direction for cost-effective CO2 reduction processes.

  14. Low aspect ratio micropores for single-particle and single-cell analysis.

    Science.gov (United States)

    Goyal, Gaurav; Mulero, Rafael; Ali, Jamel; Darvish, Armin; Kim, Min Jun

    2015-05-01

    This paper describes microparticle and bacterial translocation studies using low aspect ratio solid-state micropores. Micropores, 5 μm in diameter, were fabricated in 200 nm thick free-standing silicon nitride membranes, resulting in pores with an extremely low aspect ratio, nominally 0.04. For microparticle translocation experiments, sulfonated polystyrene microparticles and magnetic microbeads in size range of 1-4 μm were used. Using the microparticle translocation characteristics, we find that particle translocations result in a change only in the pore's geometrical resistance while the access resistance remains constant. Furthermore, we demonstrate the ability of our micropore to probe high-resolution shape information of translocating analytes using concatenated magnetic microspheres. Distinct current drop peaks were observed for each microsphere of the multibead architecture. For bacterial translocation experiments, nonflagellated Escherichia coli (strain HCB 5) and wild type flagellated Salmonella typhimurium (strain SJW1103) were used. Distinct current signatures for the two bacteria were obtained and this difference in translocation behavior was attributed to different surface protein distributions on the bacteria. Our findings may help in developing low aspect ratio pores for high-resolution microparticle characterization and single-cell analysis.

  15. CO2 Capture in the Sustainable Wheat-Derived Activated Microporous Carbon Compartments

    Science.gov (United States)

    Hong, Seok-Min; Jang, Eunji; Dysart, Arthur D.; Pol, Vilas G.; Lee, Ki Bong

    2016-10-01

    Microporous carbon compartments (MCCs) were developed via controlled carbonization of wheat flour producing large cavities that allow CO2 gas molecules to access micropores and adsorb effectively. KOH activation of MCCs was conducted at 700 °C with varying mass ratios of KOH/C ranging from 1 to 5, and the effects of activation conditions on the prepared carbon materials in terms of the characteristics and behavior of CO2 adsorption were investigated. Textural properties, such as specific surface area and total pore volume, linearly increased with the KOH/C ratio, attributed to the development of pores and enlargement of pores within carbon. The highest CO2 adsorption capacities of 5.70 mol kg‑1 at 0 °C and 3.48 mol kg‑1 at 25 °C were obtained for MCC activated with a KOH/C ratio of 3 (MCC-K3). In addition, CO2 adsorption uptake was significantly dependent on the volume of narrow micropores with a pore size of less than 0.8 nm rather than the volume of larger pores or surface area. MCC-K3 also exhibited excellent cyclic stability, facile regeneration, and rapid adsorption kinetics. As compared to the pseudo-first-order model, the pseudo-second-order kinetic model described the experimental adsorption data methodically.

  16. CO2 Capture in the Sustainable Wheat-Derived Activated Microporous Carbon Compartments

    Science.gov (United States)

    Hong, Seok-Min; Jang, Eunji; Dysart, Arthur D.; Pol, Vilas G.; Lee, Ki Bong

    2016-01-01

    Microporous carbon compartments (MCCs) were developed via controlled carbonization of wheat flour producing large cavities that allow CO2 gas molecules to access micropores and adsorb effectively. KOH activation of MCCs was conducted at 700 °C with varying mass ratios of KOH/C ranging from 1 to 5, and the effects of activation conditions on the prepared carbon materials in terms of the characteristics and behavior of CO2 adsorption were investigated. Textural properties, such as specific surface area and total pore volume, linearly increased with the KOH/C ratio, attributed to the development of pores and enlargement of pores within carbon. The highest CO2 adsorption capacities of 5.70 mol kg−1 at 0 °C and 3.48 mol kg−1 at 25 °C were obtained for MCC activated with a KOH/C ratio of 3 (MCC-K3). In addition, CO2 adsorption uptake was significantly dependent on the volume of narrow micropores with a pore size of less than 0.8 nm rather than the volume of larger pores or surface area. MCC-K3 also exhibited excellent cyclic stability, facile regeneration, and rapid adsorption kinetics. As compared to the pseudo-first-order model, the pseudo-second-order kinetic model described the experimental adsorption data methodically. PMID:27698448

  17. A single-ligand ultra-microporous MOF for precombustion CO2 capture and hydrogen purification.

    Science.gov (United States)

    Nandi, Shyamapada; De Luna, Phil; Daff, Thomas D; Rother, Jens; Liu, Ming; Buchanan, William; Hawari, Ayman I; Woo, Tom K; Vaidhyanathan, Ramanathan

    2015-12-01

    Metal organic frameworks (MOFs) built from a single small ligand typically have high stability, are rigid, and have syntheses that are often simple and easily scalable. However, they are normally ultra-microporous and do not have large surface areas amenable to gas separation applications. We report an ultra-microporous (3.5 and 4.8 Å pores) Ni-(4-pyridylcarboxylate)2 with a cubic framework that exhibits exceptionally high CO2/H2 selectivities (285 for 20:80 and 230 for 40:60 mixtures at 10 bar, 40°C) and working capacities (3.95 mmol/g), making it suitable for hydrogen purification under typical precombustion CO2 capture conditions (1- to 10-bar pressure swing). It exhibits facile CO2 adsorption-desorption cycling and has CO2 self-diffusivities of ~3 × 10(-9) m(2)/s, which is two orders higher than that of zeolite 13X and comparable to other top-performing MOFs for this application. Simulations reveal a high density of binding sites that allow for favorable CO2-CO2 interactions and large cooperative binding energies. Ultra-micropores generated by a small ligand ensures hydrolytic, hydrostatic stabilities, shelf life, and stability toward humid gas streams.

  18. Microporous and mesoporous ZSM-5 catalyst for catalytic cracking of C5 raffinate to light olefins.

    Science.gov (United States)

    Lee, Joongwon; Hong, Ung Gi; Hwang, Sunhwan; Youn, Min Hye; Song, In Kyu

    2014-11-01

    ZSM5 catalysts (PAM(X)-ZSM5) with micropores and mesopores were prepared using polyacrylamide (PAM) as a soft template at different PAM content (X = 0, 0.12, 0.25, 0.53, 0.64, and 0.78 wt%), and they were applied to the production of light olefins (ethylene and propylene) through catalytic cracking of C5 raffinate. The effect of PAM content of PAM(X)-ZSM5 catalysts on the physicochemical properties and catalytic activities was investigated. N2 adsorption-desorption isotherms of PAM(X)-ZSM5 catalysts exhibited a broad hysteresis loop at high relative pressure, indicating the existence of mesopores in the catalysts. It was found that the catalytic performance of PAM(X)-ZSM5 catalysts was closely related to the mesoporosity of the catalysts. Conversion of C5 raffinate and yield for light olefins showed volcano-shaped trends with respect to mesopore/micropore volume ratio of the catalysts. Thus, an optimal PAM content was required to achieve maximum production of light olefins through catalytic cracking of C5 raffinate over microporous and mesoporous PAM(X)-ZSM5 catalysts.

  19. Metal Microporous Aromatic Polymers with Improved Performance for Small Gas Storage.

    Science.gov (United States)

    Fu, Xian; Zhang, Yindong; Gu, Shuai; Zhu, Yunlong; Yu, Guipeng; Pan, Chunyue; Wang, Zhonggang; Hu, Yuehua

    2015-09-14

    A novel metal-doping strategy was developed for the construction of iron-decorated microporous aromatic polymers with high small-gas-uptake capacities. Cost-effective ferrocene-functionalized microporous aromatic polymers (FMAPs) were constructed by a one-step Friedel-Crafts reaction of ferrocene and s-triazine monomers. The introduction of ferrocene endows the microporous polymers with a regular and homogenous dispersion of iron, which avoids the slow reunion that is usually encountered in previously reported metal-doping procedures, permitting a strong interaction between the porous solid and guest gases. Compared to ferrocene-free analogues, FMAP-1, which has a moderate BET surface area, shows good gas-adsorption capabilities for H2 (1.75 wt % at 77 K/1.0 bar), CH4 (5.5 wt % at 298 K/25.0 bar), and CO2 (16.9 wt % at 273 K/1.0 bar), as well as a remarkably high ideal adsorbed solution theory CO2 /N2 selectivity (107 v/v at 273 K/(0-1.0) bar), and high isosteric heats of adsorption of H2 (16.9 kJ mol(-1) ) and CO2 (41.6 kJ mol(-1) ). © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  20. Modeling water adsorption in carbon micropores: study of water in carbon molecular sieves.

    Science.gov (United States)

    Rutherford, S W

    2006-01-17

    Measurements of water adsorption equilibrium in a carbon molecular sieve are undertaken in order to gain insight into the nature of water adsorption in carbon micropores. The measurements are taken at low concentrations to emphasize the role of oxygen-containing functional groups in the adsorption of water. Comparisons are made with previously published water adsorption data at higher concentrations to provide a data set spanning a wide range of loading. The assembled data set provides an opportunity for comparison of various theories for prediction of water adsorption in carbon micropores. Shortcomings of current theories are outlined, and an analytical theory that is free of these deficiencies is proposed in this investigation. With the consideration of micropore volume and pore size distribution, the experimental data and proposed isotherm model are consistent with previous studies of Takeda carbon molecular sieves. Also investigated is the uptake kinetics of water, which is characterized by a Fickian diffusion mechanism. The Maxwell-Stefan formulation is applied to characterize the dependence of the diffusional mobility upon loading.

  1. A dual-spatially-confined reservoir by packing micropores within dense graphene for long-life lithium/sulfur batteries

    Science.gov (United States)

    Li, Hongfei; Yang, Xiaowei; Wang, Xiaomin; He, Yu-Shi; Ye, Fangmin; Liu, Meinan; Zhang, Yuegang

    2016-01-01

    In lithium/sulfur batteries, micropores could bring about strong interactions with polysulfides, but could not alleviate the partial polysulfide overflowing outside because of the volume expansion of the lithiated sulfur. A dual-spatially-confined reservoir for sulfur by wrapping microporous carbon with dense graphene, micro@meso-porous DSC (dual-spatial carbon), is synthesized to solve this issue. Such a structure is prepared through two distinctive methods: graphene promoted in situ hydrothermal carbonization of organics to grow micropores on itself, and liquid mediated drying of graphene hydrogel to form mesoporous graphene frameworks. In contrast to previously reported hierarchical carbon/S, the inner micropores are mainly responsible for loading sulfur, which could help confine its particle size, thus increasing the electrical/ionic conductivity and the utilization of sulfur, and restrain lithium polysulfide dissolution because of strong interaction with pore walls; while the outer mesopores act as another reservoir to stabilize the overflowed polysulfide and to enhance the Li+ transport. The S-micro@meso-porous DSC cathode exhibits better discharge capacity and cycling performance than S-microporous AC and S-micro@macro-porous DSC, i.e., 59% and 37% higher capacity remaining at 0.5 C than the latter two, respectively.In lithium/sulfur batteries, micropores could bring about strong interactions with polysulfides, but could not alleviate the partial polysulfide overflowing outside because of the volume expansion of the lithiated sulfur. A dual-spatially-confined reservoir for sulfur by wrapping microporous carbon with dense graphene, micro@meso-porous DSC (dual-spatial carbon), is synthesized to solve this issue. Such a structure is prepared through two distinctive methods: graphene promoted in situ hydrothermal carbonization of organics to grow micropores on itself, and liquid mediated drying of graphene hydrogel to form mesoporous graphene frameworks. In

  2. Facile Carbonization of Microporous Organic Polymers into Hierarchically Porous Carbons Targeted for Effective CO2 Uptake at Low Pressures.

    Science.gov (United States)

    Gu, Shuai; He, Jianqiao; Zhu, Yunlong; Wang, Zhiqiang; Chen, Dongyang; Yu, Guipeng; Pan, Chunyue; Guan, Jianguo; Tao, Kai

    2016-07-20

    The advent of microporous organic polymers (MOPs) has delivered great potential in gas storage and separation (CCS). However, the presence of only micropores in these polymers often imposes diffusion limitations, which has resulted in the low utilization of MOPs in CCS. Herein, facile chemical activation of the single microporous organic polymers (MOPs) resulted in a series of hierarchically porous carbons with hierarchically meso-microporous structures and high CO2 uptake capacities at low pressures. The MOPs precursors (termed as MOP-7-10) with a simple narrow micropore structure obtained in this work possess moderate apparent BET surface areas ranging from 479 to 819 m(2) g(-1). By comparing different activating agents for the carbonization of these MOPs matrials, we found the optimized carbon matrials MOPs-C activated by KOH show unique hierarchically porous structures with a significant expansion of dominant pore size from micropores to mesopores, whereas their microporosity is also significantly improved, which was evidenced by a significant increase in the micropore volume (from 0.27 to 0.68 cm(3) g(-1)). This maybe related to the collapse and the structural rearrangement of the polymer farmeworks resulted from the activation of the activating agent KOH at high temperature. The as-made hierarchically porous carbons MOPs-C show an obvious increase in the BET surface area (from 819 to 1824 m(2) g(-1)). And the unique hierarchically porous structures of MOPs-C significantly contributed to the enhancement of the CO2 capture capacities, which are up to 214 mg g(-1) (at 273 K and 1 bar) and 52 mg g(-1) (at 273 K and 0.15 bar), superior to those of the most known MOPs and porous carbons. The high physicochemical stabilities and appropriate isosteric adsorption heats as well as high CO2/N2 ideal selectivities endow these hierarchically porous carbon materials great potential in gas sorption and separation.

  3. Microporous dermal-mimetic electrospun scaffolds pre-seeded with fibroblasts promote tissue regeneration in full-thickness skin wounds.

    Directory of Open Access Journals (Sweden)

    Paul P Bonvallet

    Full Text Available Electrospun scaffolds serve as promising substrates for tissue repair due to their nanofibrous architecture and amenability to tailoring of chemical composition. In this study, the regenerative potential of a microporous electrospun scaffold pre-seeded with dermal fibroblasts was evaluated. Previously we reported that a 70% collagen I and 30% poly(Ɛ-caprolactone electrospun scaffold (70:30 col/PCL containing 160 μm diameter pores had favorable mechanical properties, supported fibroblast infiltration and subsequent cell-mediated deposition of extracellular matrix (ECM, and promoted more rapid and effective in vivo skin regeneration when compared to scaffolds lacking micropores. In the current study we tested the hypothesis that the efficacy of the 70:30 col/PCL microporous scaffolds could be further enhanced by seeding scaffolds with dermal fibroblasts prior to implantation into skin wounds. To address this hypothesis, a Fischer 344 (F344 rat syngeneic model was employed. In vitro studies showed that dermal fibroblasts isolated from F344 rat skin were able to adhere and proliferate on 70:30 col/PCL microporous scaffolds, and the cells also filled the 160 μm pores with native ECM proteins such as collagen I and fibronectin. Additionally, scaffolds seeded with F344 fibroblasts exhibited a low rate of contraction (~14% over a 21 day time frame. To assess regenerative potential, scaffolds with or without seeded F344 dermal fibroblasts were implanted into full thickness, critical size defects created in F344 hosts. Specifically, we compared: microporous scaffolds containing fibroblasts seeded for 4 days; scaffolds containing fibroblasts seeded for only 1 day; acellular microporous scaffolds; and a sham wound (no scaffold. Scaffolds containing fibroblasts seeded for 4 days had the best response of all treatment groups with respect to accelerated wound healing, a more normal-appearing dermal matrix structure, and hair follicle regeneration

  4. Mild photochemical synthesis of the antioxidant hydroxytyrosol via conversion of tyrosol.

    Science.gov (United States)

    Azabou, Samia; Najjar, Wahiba; Ghorbel, Abdelhamid; Sayadi, Sami

    2007-06-13

    Hydroxytyrosol, a naturally occurred orthodiphenolic antioxidant molecule found in olive oil and olive mill wastewaters, was obtained from the wet hydrogen peroxide photocatalytic oxidation of its monophenolic precursor tyrosol. The liquid-phase oxidation of tyrosol to hydroxytyrosol was performed by use of an iron-containing heterogeneous catalyst (Al-Fe)PILC with the assistance of UV irradiation at 254 nm and at room temperature. The spectroscopic and HPLC data of the synthesized compound proved to coincide fully with those of a pure sample obtained by continuous countercurrent extraction. This reaction was found to be light-induced. The hydroxytyrosol synthesis reaction reached its maximum yield of 64.36% under the optimized operating conditions of 3.6 mM tyrosol, 0.5 g L(-1) catalyst, and 10(-2) M H2O2 with the assistance of UV light. Increasing the initial hydrogen peroxide concentration more than 10(-2) M has a diminishing return on the reaction efficiency. Catalyst can be recuperated by means of filtration and then reused in a next run after regeneration since its activity did not significantly decrease (<10%). The reaction synthesis is operationally simple and could find application for industrial purposes.

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

    Science.gov (United States)

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

    2016-06-01

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

  6. A dual-spatially-confined reservoir by packing micropores within dense graphene for long-life lithium/sulfur batteries.

    Science.gov (United States)

    Li, Hongfei; Yang, Xiaowei; Wang, Xiaomin; He, Yu-Shi; Ye, Fangmin; Liu, Meinan; Zhang, Yuegang

    2016-01-28

    In lithium/sulfur batteries, micropores could bring about strong interactions with polysulfides, but could not alleviate the partial polysulfide overflowing outside because of the volume expansion of the lithiated sulfur. A dual-spatially-confined reservoir for sulfur by wrapping microporous carbon with dense graphene, micro@meso-porous DSC (dual-spatial carbon), is synthesized to solve this issue. Such a structure is prepared through two distinctive methods: graphene promoted in situ hydrothermal carbonization of organics to grow micropores on itself, and liquid mediated drying of graphene hydrogel to form mesoporous graphene frameworks. In contrast to previously reported hierarchical carbon/S, the inner micropores are mainly responsible for loading sulfur, which could help confine its particle size, thus increasing the electrical/ionic conductivity and the utilization of sulfur, and restrain lithium polysulfide dissolution because of strong interaction with pore walls; while the outer mesopores act as another reservoir to stabilize the overflowed polysulfide and to enhance the Li(+) transport. The S-micro@meso-porous DSC cathode exhibits better discharge capacity and cycling performance than S-microporous AC and S-micro@macro-porous DSC, i.e., 59% and 37% higher capacity remaining at 0.5 C than the latter two, respectively.

  7. Bioprocess intensification of antibiotic production by Streptomyces coelicolor A3(2) in micro-porous culture

    Energy Technology Data Exchange (ETDEWEB)

    Ndlovu, T.M., E-mail: tm.ndlovu@nutriss.com [NUTRISS Limited, INEX, Herschel Annex, Kings Road, Newcastle upon Tyne NE1 7RU (United Kingdom); Ward, A.C. [School of Biology, Newcastle University, Newcastle upon Tyne, NE1 7RU (United Kingdom); Department of Microbiology, Chung-Ang University, College of Medicine, Seoul, Republic of Korea 156-756 (Korea, Republic of); Glassey, J. [School of Chemical Engineering and Advanced Materials, Newcastle University, Newcastle upon Tyne NE1 7RU (United Kingdom); Eskildsen, J. [NUTRISS Limited, INEX, Herschel Annex, Kings Road, Newcastle upon Tyne NE1 7RU (United Kingdom); Akay, G. [School of Chemical Engineering and Advanced Materials, Newcastle University, Newcastle upon Tyne NE1 7RU (United Kingdom)

    2015-04-01

    A novel functionalized micro-porous matrix was developed with well-controlled physicochemical proprieties such as pore size and surface chemistry. The matrix was used as a solid support in the growth of “Streptomyces coelicolor” A3(2) to enhance the production of antibiotics. The results shown support a higher production of prodigiosin and actinorhodin with overall production increase of 2–5 and 6–17, respectively, compared to conventional submerged liquid culture, offering a potential improvement in volumetric productivity. Scanning Electron Microscopy was used to evaluate pore size as well as bacterial adhesion, penetration, proliferation and migration within the micro-porous matrix. - Highlights: • Preparation of novel micro-porous matrix with different physiochemical proprieties • S. coelicolor A3(2) was cultured in those micro-porous and antibiotics was enhanced. • Matrix pore sizes and surface chemistry influenced bacterial signalling. • Bacterial signalling has a profound effect in the overproduction of Prodigiosin and actinorhodin. • Prodigiosin and actinorhodin production within micro-porous was 5–17 times higher compared with liquid growth.

  8. Core-shell meso/microporous carbon host for sulfur loading toward applications in lithium-sulfur batteries

    Institute of Scientific and Technical Information of China (English)

    Juan Zhang; Huan Ye; Yaxia Yin; Yuguo Guo

    2014-01-01

    Lithium-sulfur (Li-S) batteries belong to one of the promising technologies for high-energy-density rechargeable batteries. However, sulfur cathodes suffer from inherent problems of its poor electronic conductivity and the shuttling of highly dissoluble lithium polysulfides generated during the cycles. Loading sulfur into porous carbons has been proved to be an effective approach to alleviate these issues. Mesoporous and microporous carbons have been widely used for sulfur accommodation, but mesoporous carbons have poor sulfur confinement, whereas microporous carbons are impeded by low sulfur loading rates. Here, a core-shell carbon, combining both the merits of mesoporous carbon with large pore volume and microporous carbon with effective sulfur confinement, was prepared by coating the mesoporous CMK-3 with a microporous carbon (MPC) shell and served as the carbon host (CMK-3@MPC) to accommodate sulfur. After sulfur infusion, the as-obtained S/(CMK-3@MPC) cathode delivered a high initial capacity of up to 1422 mAh·g-1 and sustained 654 mAh·g-1 reversible specific capacity after 36 cycles at 0.1 C. The good performance is ascribed to the unique core-shell structure of the CMK-3@MPC matrix, in which sulfur can be effectively confined within the meso/microporous carbon host, thus achieving simultaneously high electrochemical utilization.

  9. Highly efficient indoor air purification using adsorption-enhanced-photocatalysis-based microporous TiO2 at short residence time.

    Science.gov (United States)

    Lv, Jinze; Zhu, Lizhong

    2013-01-01

    A short residence time is a key design parameter for the removal of organic pollutants in catalyst-based indoor air purification systems. In this study, we synthesized a series of TiO2 with different micropore volumes and studied their removal efficiency of indoor carbonyl pollutants at a short residence time. Our results indicated that the superior adsorption capability of TiO2 with micropores improved its performance in the photocatalytic degradation of cyclohexanone, while the photocatalytic removal of the pollutant successfully kept porous TiO2 from becoming saturated. When treated with 1 mg m(-3) cyclohexanone at a relatively humidity of 18%, the adsorption amount on microporous TiO2 was 5.4-7.9 times higher than that on P25. Removal efficiency via photocatalysis followed'the same order as the adsorption amount: TiO2-5 > TiO2-20 > TiO2-60 > TiO2-180 > P25. The advantage of microporous TiO2 over P25 became more pronounced when the residence time declined from 0.072 to 0.036 s. Moreover, as the concentration of cyclohexanone deceased from 1000 ppb to 500 ppb, removal efficiency by microporous TiO2 increased more rapidly than P25.

  10. The Influence of Micropore Oxygen Aeration on the Pond Water Quality Environment

    Directory of Open Access Journals (Sweden)

    Xiao-Jiang Chen

    2013-11-01

    Full Text Available In order to know the effects of micropore oxygen aeration on the water quality and economic output, take each 3 of micropore oxygen aeration (experimental pond and impeller oxygenation (control pond to make the comparison, indexs of two different aeration methods water were detected from May, 2012 to October, 2012. Such as water temperature, dissolved oxygen, ammonia nitrogen and nitrite, phytoplankton, chemical oxygen demand (CODMn. Results showed that, (1 the indexes of the dissolved oxygen, ammonia nitrogen, chemical oxygen demand(CODMn and nitrite of the experimental pond are all superior to that of the control pond, of which the concentration of the dissolved oxygen of the experimental pond is 8.37 mg/L which is higher than that of the control pond (5.7 mg/L. And, (CODMn in the experimental pond is 7.54 mg/L, lower than that in the control pond (10.19 mg/L. The difference between the control pond and the experimental pond was statistically significant (p<0.01. The ammonia nitrogen of the experimental pond is 0.1 mg/L, obviously lower than the control pond (0.16 mg/L. Besides, the nitrite is 0.13 mg/L in the experimental pond, lower than that of the control pond (0.21 mg/L. (2 Compared with the control pond, the experimental pond has quite higher general abundance of algae, with about 5.69×108 ind/L. Yet, there is no obvious difference between them. (3 Compared to the impeller oxygenation, the micropore oxygen aeration technology can be better to increase the dissolved oxygen in the aquaculture pond and improve the water quality. However, there is no significant influence to the phytoplankton abundance and diversity.

  11. Electroosmotic flow can generate ion current rectification in nano- and micropores.

    Science.gov (United States)

    Yusko, Erik C; An, Ran; Mayer, Michael

    2010-01-26

    This paper introduces a strategy for generating ion current rectification through nano- and micropores. This method generates ion current rectification by electroosmotic-driven flow of liquids of varying viscosity (and hence varying conductance) into or out of the narrowest constriction of a pore. The magnitude of current rectification was described by a rectification factor, R(f), which is defined by the ratio of the current measured at a positive voltage divided by the current measured at a negative voltage. This method achieved rectification factors in the range of 5-15 using pores with diameters ranging from 10 nm to 2.2 microm. These R(f) values are similar to the rectification factors reported in other nanopore-based methods that did not employ segmented surface charges. Interestingly, this work showed that in cylindrical nanopores with diameters of 10 nm and a length of at least 275 nm, electroosmotic flow was present and could generate ion current rectification. Unlike previous methods for generating ion current rectification that require nanopores with diameters comparable to the Debye length, this work demonstrated ion current rectification in micropores with diameters 500 times larger than the Debye length. Thus this method extends the concept of fluidic diodes to the micropore range. Several experiments designed to alter or remove electroosmotic flow through the pore demonstrated that electroosmotic flow was required for the mode of ion current rectification reported here. Consequently, the magnitude of current rectification could be used to indicate the presence of electroosmotic flow and the breakdown of electroosmotic flow with decreasing ionic strength and hence increasing electric double layer overlap inside nanopores.

  12. Ab initio molecular dynamics study of the interlayer and micropore structure of aqueous montmorillonite clays

    Science.gov (United States)

    Suter, James L.; Kabalan, Lara; Khader, Mahmoud; Coveney, Peter V.

    2015-11-01

    Ab initio molecular dynamics simulations have been performed to gain an understanding of the interfacial microscopic structure and reactivity of fully hydrated clay edges. The models studied include both micropore and interlayer water. We identify acidic sites through dissociation mechanisms; the resulting ions can be stabilized by both micropore and interlayer water. We find clay edges possess a complex amphoteric behavior, which depends on the face under consideration and the location of isomorphic substitution. For the neutral (1 1 0) surface, we do not observe any dissociation on the timescale accessible. The edge terminating hydroxyl groups participate in a hydrogen bonded network of water molecules that spans the interlayer between periodic images of the clay framework. With isomorphic substitutions in the tetrahedral layer of the (1 1 0) clay edge, we find the adjacent exposed apical oxygen behaves as a Brönsted base and abstracts a proton from a nearby water molecule, which in turn removes a proton from an AlOH2 group. With isomorphic substitutions in the octahedral layer of the (1 1 0) clay edge the adjacent exposed apical oxygen atom does not abstract a proton from the water molecules, but increases the number of hydrogen bonded water molecules (from one to two). Acid treated clays are likely to have both sites protonated. The (0 1 0) surface does not have the same interfacial hydrogen bonding structure; it is much less stable and we observe dissociation of half the terminal SiOH groups (tbnd Sisbnd Osbnd H → tbnd Sisbnd O- + H+) in our models. The resulting anions are stabilized by solvation from both micropore and interlayer water molecules. This suggests that, when fully hydrated, the (0 1 0) surface can act as a Brönsted acid, even at neutral pH.

  13. In situ formed lithium sulfide/microporous carbon cathodes for lithium-ion batteries.

    Science.gov (United States)

    Zheng, Shiyou; Chen, Yvonne; Xu, Yunhua; Yi, Feng; Zhu, Yujie; Liu, Yihang; Yang, Junhe; Wang, Chunsheng

    2013-12-23

    Highly stable sulfur/microporous carbon (S/MC) composites are prepared by vacuum infusion of sulfur vapor into microporous carbon at 600 °C, and lithium sulfide/microporous carbon (Li2S/MC) cathodes are fabricated via a novel and facile in situ lithiation strategy, i.e., spraying commercial stabilized lithium metal powder (SLMP) onto a prepared S/MC film cathode prior to the routine compressing process in cell assembly. The in situ formed Li2S/MC film cathode shows high Coulombic efficiency and long cycling stability in a conventional commercial Li-ion battery electrolyte (1.0 M LiPF6 + EC/DEC (1:1 v/v)). The reversible capacities of Li2S/MC cathodes remain about 650 mAh/g even after 900 charge/discharge cycles, and the Coulombic efficiency is close to 100% at a current density of 0.1C, which demonstrates the best electrochemical performance of Li2S/MC cathodes reported to date. Furthermore, this Li2S/MC film cathode fabricated via our in situ lithiation strategy can be coupled with a Li-free anode, such as graphite, carbon/tin alloys, or Si nanowires to form a rechargeable Li-ion cell. As the Li2S/MC cathode is paired with a commercial graphite anode, the full cell of Li2S/MC-graphite (Li2S-G) shows a stable capacity of around 600 mAh/g in 150 cycles. The Li2S/MC cathodes prepared by high-temperate sulfur infusion and SLMP prelithiation before cell assembly are ready to fit into current Li-ion batteries manufacturing processes and will pave the way to commercialize low-cost Li2S-G Li-ion batteries.

  14. Modeling micro-porous surfaces for secondary electron emission control to suppress multipactor

    Science.gov (United States)

    Sattler, J. M.; Coutu, R. A.; Lake, R.; Laurvick, T.; Back, T.; Fairchild, S.

    2017-08-01

    This work seeks to understand how the topography of a surface can be engineered to control secondary electron emission (SEE) for multipactor suppression. Two unique, semi-empirical models for the secondary electron yield (SEY) of a micro-porous surface are derived and compared. The first model is based on a two-dimensional (2D) pore geometry. The second model is based on a three-dimensional (3D) pore geometry. The SEY of both models is shown to depend on two categories of surface parameters: chemistry and topography. An important parameter in these models is the probability of electron emissions to escape the surface pores. This probability is shown by both models to depend exclusively on the aspect ratio of the pore (the ratio of the pore height to the pore diameter). The increased accuracy of the 3D model (compared to the 2D model) results in lower electron escape probabilities with the greatest reductions occurring for aspect ratios less than two. In order to validate these models, a variety of micro-porous gold surfaces were designed and fabricated using photolithography and electroplating processes. The use of an additive metal-deposition process (instead of the more commonly used subtractive metal-etch process) provided geometrically ideal pores which were necessary to accurately assess the 2D and 3D models. Comparison of the experimentally measured SEY data with model predictions from both the 2D and 3D models illustrates the improved accuracy of the 3D model. For a micro-porous gold surface consisting of pores with aspect ratios of two and a 50% pore density, the 3D model predicts that the maximum total SEY will be one. This provides optimal engineered surface design objectives to pursue for multipactor suppression using gold surfaces.

  15. Method and electrochemical cell for synthesis and treatment of metal monolayer electrocatalysts metal, carbon, and oxide nanoparticles ion batch, or in continuous fashion

    Science.gov (United States)

    Adzic, Radoslav; Zhang, Junliang; Sasaki, Kotaro

    2015-04-28

    An apparatus and method for synthesis and treatment of electrocatalyst particles in batch or continuous fashion is provided. In one embodiment, the apparatus comprises a sonication bath and a two-compartment chamber submerged in the sonication bath. The upper and lower compartments are separated by a microporous material surface. The upper compartment comprises a cover and a working electrode (WE) connected to a Pt foil contact, with the foil contact connected to the microporous material. The upper chamber further comprises reference counter electrodes. The lower compartment comprises an electrochemical cell containing a solution of metal ions. In one embodiment, the method for synthesis of electrocatalysts comprises introducing a plurality of particles into the apparatus and applying sonication and an electrical potential to the microporous material connected to the WE. After the non-noble metal ions are deposited onto the particles, the non-noble metal ions are displaced by noble-metal ions by galvanic displacement.

  16. Method and electrochemical cell for synthesis and treatment of metal monolayer electrocatalysts metal, carbon, and oxide nanoparticles ion batch, or in continuous fashion

    Energy Technology Data Exchange (ETDEWEB)

    Adzic, Radoslav; Zhang, Junliang; Sasaki, Kotaro

    2015-04-28

    An apparatus and method for synthesis and treatment of electrocatalyst particles in batch or continuous fashion is provided. In one embodiment, the apparatus comprises a sonication bath and a two-compartment chamber submerged in the sonication bath. The upper and lower compartments are separated by a microporous material surface. The upper compartment comprises a cover and a working electrode (WE) connected to a Pt foil contact, with the foil contact connected to the microporous material. The upper chamber further comprises reference counter electrodes. The lower compartment comprises an electrochemical cell containing a solution of metal ions. In one embodiment, the method for synthesis of electrocatalysts comprises introducing a plurality of particles into the apparatus and applying sonication and an electrical potential to the microporous material connected to the WE. After the non-noble metal ions are deposited onto the particles, the non-noble metal ions are displaced by noble-metal ions by galvanic displacement.

  17. Dynamic nuclear polarization NMR spectroscopy allows high-throughput characterization of microporous organic polymers.

    Science.gov (United States)

    Blanc, Frédéric; Chong, Samantha Y; McDonald, Tom O; Adams, Dave J; Pawsey, Shane; Caporini, Marc A; Cooper, Andrew I

    2013-10-16

    Dynamic nuclear polarization (DNP) solid-state NMR was used to obtain natural abundance (13)C and (15)N CP MAS NMR spectra of microporous organic polymers with excellent signal-to-noise ratio, allowing for unprecedented details in the molecular structure to be determined for these complex polymer networks. Sensitivity enhancements larger than 10 were obtained with bis-nitroxide radical at 14.1 T and low temperature (∼105 K). This DNP MAS NMR approach allows efficient, high-throughput characterization of libraries of porous polymers prepared by combinatorial chemistry methods.

  18. FABRICATION OF MICROPOROUS SILICA CERAMICS WITH VARIED POLYMORPHIC FORMS AND INVESTIGATION OF THEIR THERMAL SHOCK BEHAVIOUR

    OpenAIRE

    Şan, Osman; Koç, Muhterem

    2011-01-01

    In this study; the SiO2 micro-porous ceramics in the phase α-quartz, α-cristobalite and β-cristobalite were produced and thermal shock resistance of products were compared. In the production of ceramic materials; α-quartz obtained from natural quartz powder, α-cristobalite from pure silica powder which prepared by Stöber technique and β-cristobalite from sol-gel approach. The β-composition was designed as 1 x x x / 2 2 Si Al Ca O - where x = 0.05 and obt...

  19. EXPERIMENTAL STUDY ON THE GAS-LIQUID FLOW IN THE MEMBRANE MICROPORE AERATION BIOREACTOR

    Directory of Open Access Journals (Sweden)

    DONG LIU

    2008-12-01

    Full Text Available Particle Image Velocimetry (PIV has been developed to measure the typical two-phase flow of various work conditions in Membrane Micropore Aeration Bioreactor (MMAB. The fluid phase is separated out using image processing techniques, which provides accurate measurements for the Bioreactor’s flow field, and makes it possible for quantitative analysis of the momentum exchange, heat exchange and the process of micro-admixture. The experimental method PIV used in this paper can preferably measure the complex flow in the reactor and initiates a new approach for the bioreactor design which mainly depends on experience at present.

  20. H{sub 2} storage in microporous materials: a comparison between zeolites and Mos

    Energy Technology Data Exchange (ETDEWEB)

    Ricchiardi, G.; Regli, L.; Vitillo, J. G.; Cocina, D.; Bordiga, S.; Lamberti, C.; Spoto, G.; Zecchina, A.; Bjorgen, M.; Lillerud, K. P.

    2005-07-01

    One of the main concerns about a hydrogen-based energy economy is the efficient storage and transport of this highly flammable gas. Many strategies have been followed or suggested in recent years to solve this problem. The most important ones are: 1) storage in metals and alloys; 2) storage in complex hydrides (alanates, borides); 3) storage by trapping in clathrates (ice and others); 4) storage in microporous materials (carbons, zeolitic materials, metal-organic frameworks, polymers). [1, 2] In this work we have focused our attention on microporous materials, where the crucial point is the strength of the interaction between the molecular hydrogen and the internal surfaces of micropores and/ or of cages of entrapping materials. It is known from fundamental studies that H2 strongly interacts with ions in the gas but that the presence of counterions decreases the interaction energy substantially. The most prominent class of microporous materials, which contains isolated and exposed cations, are zeolites and zeotypes: ideal systems to investigate the interaction of H2 with both dispersive and electrostatic forces [3]. So, even if they are not sufficiently light to represent the final solution to H2 storage, the availability of a large variety of frameworks and chemical compositions combined with low cost and superior mechanical and thermal stabilities increases the interest in these materials. In this work we have studied in detail, by means of volumetric and spectroscopic measurements, zeolites with CHA topology (as they are characterized by a strong acidity and by a big surface area). H-SSZ-13 zeolite, characterized by a low Al content (Si/Al = 11), has shown the best properties in hydrogen storage in respect to all the other zeolites and zeotypes with different compositions and topologies [4]. The results have been compared with those obtained for MOF-5 [5], a well known Metal-Organic Framework, indicated as a very good material for molecular hydrogen storage [6

  1. FORMATION AND MICROSTRUCTURE OF POLYETHYLENE MICROPOROUS MEMBRANES THROUGH THERMALLY INDUCED PHASE SEPARATION

    Institute of Scientific and Technical Information of China (English)

    LI Wenjun; YUAN Youxin; CABASSO,Israel

    1995-01-01

    Microporous membranes of low-high density polyethylene and their blends were prepared by thermally-induced phase separation of polymer/long-aliphatic chain alcohol (diluent)mixtures.The microstructures of this particular membrane, which depends on the diluent properties,polymer concentration and cooling rate, were observed by scanning electron microscopy."Beehive-type,"leafy-like, and lacy porous structure morphologies can be formed,depending on the blend composition and phase separation conditions, which were discussed by the polymer and diluent crystallization processes.

  2. RPM3: a multifunctional microporous MOF with recyclable framework and high H2 binding energy.

    Science.gov (United States)

    Lan, Anjian; Li, Kunhao; Wu, Haohan; Kong, Lingzhu; Nijem, Nour; Olson, David H; Emge, Thomas J; Chabal, Yves J; Langreth, David C; Hong, Maochun; Li, Jing

    2009-08-03

    A microporous metal organic framework structure, Zn(2)(bpdc)(2)(bpee).2DMF (DMF: N,N-dimethylformamide), has been synthesized via solvothermal reactions. The compound is a new member of the RPM series (RPM = Rutgers Recyclable Porous Material) that possesses a flexible and recyclable three-dimensional framework containing one-dimensional channels. It exhibits interesting and multifold functionality, including porosity, commensurate adsorption for hydrocarbons, high hydrogen binding energy (determined by isosteric heats of hydrogen adsorption and confirmed by van der Waals density functional calculations) as a result of multifold binding to aromatic ligands (determined by IR spectroscopy), strong photoluminescence emission, and reversible fluorescence quenching properties.

  3. Conjugated Microporous Poly(Benzochalcogenadiazole)s for Photocatalytic Oxidative Coupling of Amines under Visible Light.

    Science.gov (United States)

    Wang, Zi Jun; Garth, Kim; Ghasimi, Saman; Landfester, Katharina; Zhang, Kai A I

    2015-10-26

    Metal-free visible-light photocatalysts offer a clean, sustainable solution to many pressing environmental issues. Herein, we present a molecular design strategy to fine-tune the valence and conduction band levels of a series of conjugated microporous polymer networks based on poly(benzochalcogenadiazole) for heterogeneous photocatalysis. Enhanced photocatalytic efficiency was observed by altering the chalcogene moieties in the electron-accepting benzochalcogenadiazole unit of the polymer backbone structure. Photooxidative coupling of benzylamines was chosen as a model reaction. This design strategy leading to enhanced efficiency could potentially improve a wide range of photoredox reactions.

  4. Importance of Micropore-Mesopore Interfaces in Carbon Dioxide Capture by Carbon-Based Materials.

    Science.gov (United States)

    Durá, Gema; Budarin, Vitaliy L; Castro-Osma, José A; Shuttleworth, Peter S; Quek, Sophie C Z; Clark, James H; North, Michael

    2016-08-01

    Mesoporous carbonaceous materials (Starbons®) derived from low-value/waste bio-resources separate CO2 from CO2 /N2 mixtures. Compared to Norit activated charcoal (AC), Starbons® have much lower microporosities (8-32 % versus 73 %) yet adsorb up to 65 % more CO2 . The presence of interconnected micropores and mesopores is responsible for the enhanced CO2 adsorption. The Starbons® also showed three-four times higher selectivity for CO2 adsorption rather than N2 adsorption compared to AC.

  5. Development of a New Combinatorial Approach to Multifunctional Catalysts: Metal Silsesquioxanes as Precursors to Microporous Metallosilicates

    Institute of Scientific and Technical Information of China (English)

    MAXIM, Nicolae

    2001-01-01

    Microporous, silica-supported netal oxides with a very narrow pore size distribution around 0.6 nm diameter, typicalsurface areas ranging from 350 to 700 m2/g, and loadings of well-dispersed metal oxide (up to w=10% of metal) result from thecontrolled calcination of silsesquioxane metal complexes. A versatile new methodology is envisioned that, in a combinatorial fashion, enables catalyst preparation with control over metal content and dispersity, together with adjustable Lewis and Bronsted acidity, In addition, the method is suitable for the preparation of bi-andmultifunctional catalysts containing different metals.

  6. Hierarchical zeolites: Enhanced utilisation of microporous crystals in catalysis by advances in materials design

    DEFF Research Database (Denmark)

    Perez-Ramirez, Javier; Christensen, Claus H.; Egeblad, Kresten

    2008-01-01

    in these materials often imposes intracrystalline diffusion limitations, rendering low utilisation of the zeolite active volume in catalysed reactions. This critical review examines recent advances in the rapidly evolving area of zeolites with improved accessibility and molecular transport. Strategies to enhance...... the properties of the resulting materials and the catalytic function. We particularly dwell on the exciting field of hierarchical zeolites, which couple in a single material the catalytic power of micropores and the facilitated access and improved transport consequence of a complementary mesopore network...

  7. Rationally tuned micropores within enantiopure metal-organic frameworks for highly selective separation of acetylene and ethylene.

    Science.gov (United States)

    Xiang, Sheng-Chang; Zhang, Zhangjing; Zhao, Cong-Gui; Hong, Kunlun; Zhao, Xuebo; Ding, De-Rong; Xie, Ming-Hua; Wu, Chuan-De; Das, Madhab C; Gill, Rachel; Thomas, K Mark; Chen, Banglin

    2011-02-22

    Separation of acetylene and ethylene is an important industrial process because both compounds are essential reagents for a range of chemical products and materials. Current separation approaches include the partial hydrogenation of acetylene into ethylene over a supported Pd catalyst, and the extraction of cracked olefins using an organic solvent; both routes are costly and energy consuming. Adsorption technologies may allow separation, but microporous materials exhibiting highly selective adsorption of C(2)H(2)/C(2)H(4) have not been realized to date. Here, we report the development of tunable microporous enantiopure mixed-metal-organic framework (M'MOF) materials for highly selective separation of C(2)H(2) and C(2)H(4). The high selectivities achieved suggest the potential application of microporous M'MOFs for practical adsorption-based separation of C(2)H(2)/C(2)H(4).

  8. Micropore diffusion in coal chars under reactive conditions: Quarterly technical progress report, 15 September 1986-15 December 1986

    Energy Technology Data Exchange (ETDEWEB)

    Calo, J.M.

    1986-01-01

    This project is concerned with the development of a new technique for measuring the rates of diffusion of gases on the microporous structure of coal chars. Mass transport in pores of molecular dimensions is known to be an activated, relatively slow process. The gasification of coal chars may be transport-limited. To correlate and predict gasification reactivity, it is quite important to know over what range of conditions such limitations may control. The initial transient behavior of a gaseous species exposed to such chars primarily reflects the transport resistance offered by the micropores. When this process is conducted using a well-defined perturbation in a mixed reactor, the diffusion step can often be separated from the subsequent reaction steps, so that measurements can be conducted under actual gasification conditions. We will apply this technique to a few well-characterized coal/carbon chars. Micropore diffusion times in these samples will be determined for various gaseous species relevant to the gasification environments. The primary variables will be temperature and degree of conversion (i.e., burn-off). Measurements will be examined with respect to changes occurring in the pore structure of the chars. In this first quarterly technical progress report, the background and objectives of the study and the requisite experimental preparations to begin the micropore diffusion studies are presented. In particular, during the reporting period: the graduate assistant on this project conducted a literature review of the general area of micropore diffusion and began to acquire the necessary background for the experimental study; the inception of a pore model was undertaken involving micropore diffusion; and the Autoclave Engineers 3'' Berty catalytic reactor has been refurbished and modified for the study. 59 refs., 2 figs.

  9. A Novel Micro-porous Polymer Electrolyte Comprising SnO_2 Nanorods and P(MMA-AN)

    Institute of Scientific and Technical Information of China (English)

    P.Zhang; H.P.Zhang; Z.H.Li; Y.P.Wu

    2007-01-01

    1 Results Micro-porous polymer electrolytes(MPEs), which almost obtained by the conventional methods of phase inversion process or immersion precipitation method, have significant advantages such as high ionic conductivity and excellent mechanical properties[1].In our work, micro-porous structure is obtained by adding SnO2 nanorods usually used as gas senor materials into the polymer matrix, which proves a new way to prepare MPEs.SnO2 nanorods were synthesized by microemulsion hydrothermal method[2]. Th...

  10. Using Microporous Polytetrafluoroethylene Thin Sheets as a Flexible Solar Diffuser to Minimize Sunlight Glint to Cameras in Space

    Science.gov (United States)

    Choi, Michael K.

    2016-01-01

    An innovative design of using microporous PTFE thin sheets as a solar diffuser for MLI blankets or mechanical structure has been developed. It minimizes sunlight or stray-light glint to cameras when it is incident on these components in space. A microporous black PTFE thin sheet solar diffuser has been qualified for flight at NASA GSFC and installed to the TAGSAM arm MLI, OCAMS PolyCam sunshade MLI and SamCam motor riser MLI in the NASA OSIRIS-REx mission to meet the SamCam camera BRDF requirement.

  11. Inelastic neutron scattering study of binding of para-hydrogen in an ultra-microporous metal-organic framework

    OpenAIRE

    Yang, Sihai; Ramirez - Cuesta, Anibal J.; Schröder, Martin

    2014-01-01

    Metal-organic framework (MOF) materials show promise for H2 storage and it is widely predicted by computational modelling that MOFs incorporating ultra-micropores are optimal for H2 binding due to enhanced overlapping potentials. We report the investigation using inelastic neutron scattering of the interaction of H2 in an ultra-microporous MOF material showing low H2 uptake capacity. The study has revealed that adsorbed H2 at 5 K has a liquid recoil motion along the channel with very little i...

  12. Enhancement of Heat Transfer with Pool and Spray Impingement Boiling on Microporous and Nanowire Surface Coatings

    Energy Technology Data Exchange (ETDEWEB)

    Thiagarajan, S. J.; Wang, W.; Yang, R.; Narumanchi, S.; King, C.

    2010-09-01

    The DOE National Renewable Energy Laboratory (NREL) is leading a national effort to develop next-generation cooling technologies for hybrid vehicle electronics. The goal is to reduce the size, weight, and cost of power electronic modules that convert direct current from batteries to alternating current for the motor, and vice versa. Aggressive thermal management techniques help to increase power density and reduce weight and volume, while keeping chip temperatures within acceptable limits. The viability of aggressive cooling schemes such as spray and jet impingement in conjunction with enhanced surfaces is being explored. Here, we present results from a series of experiments with pool and spray boiling on enhanced surfaces, such as a microporous layer of copper and copper nanowires, using HFE-7100 as the working fluid. Spray impingement on the microporous coated surface showed an enhancement of 100%-300% in the heat transfer coefficient at a given wall superheat with respect to spray impingement on a plain surface under similar operating conditions. Critical heat flux also increased by 7%-20%, depending on flow rates.

  13. Injectable and microporous scaffold of densely-packed, growth factor-encapsulating chitosan microgels.

    Science.gov (United States)

    Riederer, Michael S; Requist, Brennan D; Payne, Karin A; Way, J Douglas; Krebs, Melissa D

    2016-11-01

    In this work, an emulsion crosslinking method was developed to produce chitosan-genipin microgels which acted as an injectable and microporous scaffold. Chitosan was characterized with respect to pH by light scattering and aqueous titration. Microgels were characterized with swelling, light scattering, and rheometry of densely-packed microgel solutions. The results suggest that as chitosan becomes increasingly deprotonated above the pKa, repulsive forces diminish and intermolecular attractions cause pH-responsive chain aggregation; leading to microgel-microgel aggregation as well. The microgels with the most chitosan and least cross-linker showed the highest yield stress and a storage modulus of 16kPa when condensed as a microgel paste at pH 7.4. Two oppositely-charged growth factors could be encapsulated into the microgels and endothelial cells were able to proliferate into the 3D microgel scaffold. This work motivates further research on the applications of the chitosan microgel scaffold as an injectable and microporous scaffold in regenerative medicine.

  14. Enhanced adsorption of humic acids on ordered mesoporous carbon compared with microporous activated carbon.

    Science.gov (United States)

    Liu, Fengling; Xu, Zhaoyi; Wan, Haiqin; Wan, Yuqiu; Zheng, Shourong; Zhu, Dongqiang

    2011-04-01

    Humic acids are ubiquitous in surface and underground waters and may pose potential risk to human health when present in drinking water sources. In this study, ordered mesoporous carbon was synthesized by means of a hard template method and further characterized by X-ray diffraction, N2 adsorption, transition electron microscopy, elemental analysis, and zeta-potential measurement. Batch experiments were conducted to evaluate adsorption of two humic acids from coal and soil, respectively, on the synthesized carbon. For comparison, a commercial microporous activated carbon and nonporous graphite were included as additional adsorbents; moreover, phenol was adopted as a small probe adsorbate. Pore size distribution characterization showed that the synthesized carbon had ordered mesoporous structure, whereas the activated carbon was composed mainly of micropores with a much broader pore size distribution. Accordingly, adsorption of the two humic acids was substantially lower on the activated carbon than on the synthesized carbon, because of the size-exclusion effect. In contrast, the synthesized carbon and activated carbon showed comparable adsorption for phenol when the size-exclusion effect was not in operation. Additionally, we verified by size-exclusion chromatography studies that the synthesized carbon exhibited greater adsorption for the large humic acid fraction than the activated carbon. The pH dependence of adsorption on the three carbonaceous adsorbents was also compared between the two test humic acids. The findings highlight the potential of using ordered mesoporous carbon as a superior adsorbent for the removal of humic acids.

  15. A transverse isotropic model for microporous solids: Application to coal matrix adsorption and swelling

    Science.gov (United States)

    Espinoza, D. N.; Vandamme, M.; Dangla, P.; Pereira, J.-M.; Vidal-Gilbert, S.

    2013-12-01

    Understanding the adsorption-induced swelling in coal is critical for predictable and enhanced coal bed methane production. The coal matrix is a natural anisotropic disordered microporous solid. We develop an elastic transverse isotropic poromechanical model for microporous solids which couples adsorption and strain through adsorption stress functions and expresses the adsorption isotherm as a multivariate function depending on fluid pressure and solid strains. Experimental data from the literature help invert the anisotropic adsorptive-mechanical properties of Brzeszcze coal samples exposed to CO2. The main findings include the following: (1) adsorption-induced swelling can be modeled by including fluid-specific and pressure-dependent adsorption stress functions into equilibrium equations, (2) modeling results suggest that swelling anisotropy is mostly caused by anisotropy of the solid mechanical properties, and (3) the total amount of adsorbed gas measured by immersing coal in the adsorbate overestimates adsorption amount compared to in situ conditions up to ˜20%. The developed fully coupled model can be upscaled to determine the coal seam permeability through permeability-stress relationships.

  16. Three-dimensional microporous polypyrrole/polysulfone composite film electrode for supercapacitance performance

    Energy Technology Data Exchange (ETDEWEB)

    Feng, Xiaojuan, E-mail: cherry-820@163.com; Shi, Yanlong; Jin, Shuping

    2015-10-30

    The three-dimensional microporous polypyrrole/polysulfone (PPY/PSF) composite film was fabricated via a simple polymerization method. The morphology structure and chemical composition of the composite film were characterized by scanning electron microscopy (SEM) and Fourier transform infrared spectroscopy (FTIR), respectively. The electrochemical properties of the composite film electrode were evaluated by cyclic voltammetry, galvanostatic charging-discharging and electrochemical impedance spectroscopy. The material exhibits excellent capacitance performance including high capacitance of 500 F g{sup −1} at 0.3 A g{sup −1} current density, good cycle stability in 800 continuous cycles (only 4.5% decay after 800 cycles at 0.3 A g{sup −1}), and low inter resistance. The good property of the PPY/PSF electrode should be attributed to its structural features, including two-layer microporous structure which facilitates the penetration of electrolytes into the inner surface, high surface area which provides more active sites. These results show that the composite film is a promising candidate for high energy electrochemical capacitors.

  17. On an isotherm thermodynamically consistent in Henry's region for describing gas adsorption in microporous materials.

    Science.gov (United States)

    Pera-Titus, Marc

    2010-05-15

    The Dubinin-Astakhov and Dubinin-Radushkevich isotherms, originally formulated from the classical volume filling theory of micropores, constitute the most accepted models for describing gas adsorption in microporous materials. The most important weakness of these equations relies on the fact that they do not reduce to Henry's law at low pressures, not providing therefore a proper characterization of adsorbents in the early stage of adsorption. In this paper, we propose a way out of this inherent problem using the thermodynamic isotherm developed in a previous study [J. Llorens, M. Pera-Titus, J. Colloid Interface Sci. 331 (2009) 302]. This isotherm allows the generation of a series of equations that make available a comprehensive description of gas adsorption for the whole set of relative pressures (including Henry's region), also providing explicit information about energy heterogeneity of the adsorbent through the two characteristic m parameters of the thermodynamic isotherm (i.e., m(1) and m(2)). The obtained isotherm converges into the Dubinin-Astakhov isotherm for relative pressures higher than 0.1, the characteristic α parameter of this isotherm being expressed as α=m(2)-1 and the affinity coefficient (β) as a sole function of m(2). An expression differing from the Dubinin-Astakhov isotherm has been obtained for describing Henry's region, providing relevant information about confinement effects when applied to zeolites.

  18. Microporous Titanium through Metal Injection Moulding of Coarse Powder and Surface Modification by Plasma Oxidation

    Directory of Open Access Journals (Sweden)

    Mohammed Menhal Shbeh

    2017-01-01

    Full Text Available Titanium is one of the most attractive materials for biomedical applications due to having excellent biocompatibility accompanied by good corrosion resistance. One popular processing technique for Ti is Metal Injection Moulding (MIM. However, there are several issues associated with the use of this technique, such as the high cost of the fine powder used, the high level of contamination and consequent alteration to material properties, as well as the large volume shrinkage that occurs during sintering. In this study, the use of a relatively coarse Ti powder with a mean particle size of 75 μm to process Ti parts with the potential for biomedical applications by MIM will be examined, compared to a commercial Ti feedstock, and subsequently coated using Plasma Electrolytic Oxidation (PEO. The results show that samples produced with the coarse powder shrink 35% less and have a relative density 14% less with an average pore size three-times larger than that of the commercial feedstock. This helps increase the potential competitiveness of MIM in the production of biomedical parts, as it reduces cost, shrinkage and results in more intentionally-induced micropores, such as are desired for biomedical implants. PEO treatment of the samples yields a thick rough coating comprised of a mixture of rutile and anatase with interconnected microporous channels and openings resembling the mouth of a volcanic crater.

  19. 3D Microporous Scaffolds Manufactured via Combination of Fused Filament Fabrication and Direct Laser Writing Ablation

    Directory of Open Access Journals (Sweden)

    Mangirdas Malinauskas

    2014-09-01

    Full Text Available A 3D printing fused filament fabrication (FFF approach has been implemented for the creation of microstructures having an internal 3D microstructure geometry. These objects were produced without any sacrificial structures or additional support materials, just by precisely tuning the nozzle heating, fan cooling and translation velocity parameters. The manufactured microporous structures out of polylactic acid (PLA had fully controllable porosity (20%–60% and consisted of desired volume pores (~0.056 μm3. The prepared scaffolds showed biocompatibility and were suitable for the primary stem cell growth. In addition, direct laser writing (DLW ablation was employed to modify the surfaces of the PLA structures, drill holes, as well as shape the outer geometries of the created objects. The proposed combination of FFF printing with DLW offers successful fabrication of 3D microporous structures with functionalization capabilities, such as the modification of surfaces, the generation of grooves and microholes and cutting out precisely shaped structures (micro-arrows, micro-gears. The produced structures could serve as biomedical templates for cell culturing, as well as biodegradable implants for tissue engineering. The additional micro-architecture is important in connection with the cell types used for the intention of cell growing. Moreover, we show that surface roughness can be modified at the nanoscale by immersion into an acetone bath, thus increasing the hydrophilicity. The approach is not limited to biomedical applications, it could be employed for the manufacturing of bioresorbable 3D microfluidic and micromechanic structures.

  20. MICROPOROUS PVDF-HFP-BASED POLYMER MEMBRANES FORMED FROM SUPERCRITICAL CO2 INDUCED PHASE SEPARATION

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    Microporous poly(vinylidene fluoride-co-hexafluoropropylene)(PVDF-HFP)membranes following supercritical CO2 induced phase separation process were prepared using four solvents.The solid electrolytes of PVDF-HFP were formed by microporous PVDF-HFP membranes filled and swollen by a liquid electrolyte.The effect of the solvents on the morphology and structure,electrolyte absorptions and lithium ionic conductivity of the activated membranes were investigated.It was approved that all the membrane had the similar"sponge-like"and asymmetric structure when different solvent was used.As the mutual affinity between solvent and supercritical CO2 decreased,the membrane porosity and the average pore diameter increased.The PVDF-HFP membrane with porosity at 88% and pore size at 10 μm were successfully prepared.The uptake of electrolyte solution and lithium ionic conductivity could reach 487 wt% and 3.09×10-3 S/cm respectively for obtained membrane.

  1. Effects of bentonite clay solids on poliovirus concentration from water by microporous filter methods.

    Science.gov (United States)

    Sobsey, M D; Cromeans, T

    1985-01-01

    To determine whether suspended solids interfere with enteric virus recovery from water by microporous filter methods, the effects of bentonite clay solids at a concentration of 10 nephelometric turbidity units on the recovery of poliovirus type 1 from seeded, activated carbon-treated, filtered tap water were studied. Volumes (500 ml) of virus-laden water at pH 5.5 or 7.5, with and without 50 mM MgCl2, were filtered through 47-mm-diameter, electropositive (Virosorb 1MDS) and electronegative (Filterite) filters that had been pretreated with Tween 80 to minimize direct virus adsorption to filter surfaces. Bentonite solids enhanced virus retention on both types of filters, even under conditions in which viruses were not solids associated. However, bentonite solids also interfered with elution of retained viruses when eluting with 0.3% beef extract-50 mM glycine (pH 9.5). Under some conditions, overall virus recoveries were lower from water with bentonite solids than from solids-free control water. The results of this study indicate that clay turbidity can interfere somewhat with virus recovery by current microporous filter methods. PMID:2988438

  2. Enhancement of Pool Boiling Heat Transfer in Water Using Sintered Copper Microporous Coatings

    Directory of Open Access Journals (Sweden)

    Seongchul Jun

    2016-08-01

    Full Text Available Pool boiling heat transfer of water saturated at atmospheric pressure was investigated experimentally on Cu surfaces with high-temperature, thermally-conductive, microporous coatings (HTCMC. The coatings were created by sintering Cu powders on Cu surfaces in a nitrogen gas environment. A parametric study of the effects of particle size and coating thickness was conducted using three average particle sizes (APSs of 10 μm, 25 μm, and 67 μm and various coating thicknesses. It was found that nucleate boiling heat transfer (NBHT and critical heat flux (CHF were enhanced significantly for sintered microporous coatings. This is believed to have resulted from the random porous structures that appear to include reentrant type cavities. The maximum NBHT coefficient was measured to be approximately 400 kW/m2k with APS 67 μm and 296 μm coating thicknesses. This value is approximately eight times higher than that of a plain Cu surface. The maximum CHF observed was 2.1 MW/m2 at APS 67 μm and 428 μm coating thicknesses, which is approximately double the CHF of a plain Cu surface. The enhancement of NBHT and CHF appeared to increase as the particle size increased in the tested range. However, two larger particle sizes (25 μm and 67 μm showed a similar level of enhancement.

  3. Development and Characterization of Non-Conventional Micro-Porous Layers for PEM Fuel Cells

    Directory of Open Access Journals (Sweden)

    Riccardo Balzarotti

    2015-07-01

    Full Text Available Gas diffusion medium (GDM is a crucial component in proton exchange membrane fuel cells (PEMFCs. Being composed of a gas diffusion layer (GDL with a micro-porous layer (MPL coated onto it, it ensures a proper water management due to the highly hydrophobic materials employed in cell assembly. In current commercial applications, the desired water repellent behaviour is usually obtained by using polytetrafluoroethylene (PTFE. In this work, Fluorolink® P56 (Solvay Specialty Polymers, Milan, Italy, a commercially available, anionic, segmented high molecular weight polyfluorourethane with perfluoropolyether groups was extensively evaluated as an alternative to PTFE for micro-porous layer hydrophobization. A change in polymer used is desirable in order to simplify the production process, both in terms of ink formulation and thermal treatment, as well as to get a higher hydrophobicity and, consequently, more efficient water management. Innovative prepared samples were compared to a PTFE-based GDM, in order to assess differences both from morphological and from an electrochemical point of view.

  4. Laser Engineering Net Shaping (LENSTM of Micro-porous Ti-6Al-4V Filters

    Directory of Open Access Journals (Sweden)

    Amit Bandyopadhyay

    2016-10-01

    Full Text Available In many applications porous metal structures are necessary for proper and optimal function. Yet these structures can be difficult to build. It is especially difficult if the pore size desired is very fine or on the micro scale. For this reason, additive manufacturing processes have been looked at to build these structures. In this study LENS processing was experimented with to see if it could be a viable process to create micro-porous interconnected structures. Using Ti6Al4V and only changing processing parameters, porous structures were created having porosity ranging from 21.5% to 15.4%. The microstructure proved to be that of traditional laser processed Ti6Al4V parts. Compression test of the samples showed that the ultimate compressive strength varied from 645-556MPa. Overall LENS proved to be a viable method to make unique micro-porous interconnected structures that could be easily added to any build without having to change the design.

  5. Automated and inexpensive method to manufacture solid- state nanopores and micropores in robust silicon wafers

    Science.gov (United States)

    Vega, M.; Granell, P.; Lasorsa, C.; Lerner, B.; Perez, M.

    2016-02-01

    In this work an easy, reproducible and inexpensive technique for the production of solid state nanopores and micropores using silicon wafer substrate is proposed. The technique is based on control of pore formation, by neutralization etchant (KOH) with a strong acid (HCl). Thus, a local neutralization is produced around the nanopore, which stops the silicon etching. The etching process was performed with 7M KOH at 80°C, where 1.23µm/min etching speed was obtained, similar to those published in literature. The control of the pore formation with the braking acid method was done using 12M HCl and different extreme conditions: i) at 25°C, ii) at 80°C and iii) at 80°C applying an electric potential. In these studies, it was found that nanopores and micropores can be obtained automatically and at a low cost. Additionally, the process was optimized to obtain clean silicon wafers after the pore fabrication process. This method opens the possibility for an efficient scale-up from laboratory production.

  6. Structural heterogeneity of microporous materials from nitrogen adsorption at 77 K

    Directory of Open Access Journals (Sweden)

    Gil, A.

    2000-08-01

    Full Text Available The structural heterogeneity of four microporous materials, namely an alumina pillared clay; an activated carbon and two zeolites, Y-82 and ZSM-5, and of their physical binary mixtures (50-50 wt% has been studied by nitrogen adsorption at 77 K. The Dubinin-Radushkevich (DR and Dubinin-Astakhov (DA equations have been applied to characterize the microporous properties and to obtain the adsorption potential distributions.

    La heterogeneidad estructural de cuatro materiales microporosos (una arcilla intercalada con una disolución hidrolizada de aluminio; un carbón activado y dos zeolitas comerciales, Y-82 y ZSM-5, así como sus respectivas mezclas físicas binarias (50- 50 % en peso se analizaron a partir de la adsorción de nitrógeno a la temperatura de 77 K. Las ecuaciones de Dubinin- Radushkevich (DR y de Dubinin-Astakhov (DA se emplearon para caracterizar las propiedades microporosas de estos materiales, así como para obtener las distribuciones de potencial de adsorción.

  7. Microporous and mesoporous carbide-derived carbons for strain modification of electromechanical actuators.

    Science.gov (United States)

    Torop, Janno; Arulepp, Mati; Sugino, Takushi; Asaka, Kinji; Jänes, Alar; Lust, Enn; Aabloo, Alvo

    2014-03-18

    Low-voltage stimuli-responsive actuators based on carbide-derived carbon (CDC) porous structures were demonstrated. Bending actuators showed a differential electromechanical response defined by the porosity of the CDC used in the electrode layer. Highly porous CDCs prepared from TiC (mainly microporous), B4C (micromesoporous), and Mo2C (mainly mesoporous) precursors were selected to demonstrate the influence of porosity parameters on the electromechanical performance of actuators. CDC-based bending-type actuators showed a porosity-driven displacement response over a frequency range of 200 to 0.005 Hz at an applied excitation voltage of ±2 V. The displacement response of the CDC actuators increased with an increasing number of mesopores in the electrode layer, and the generated strain of the bending actuators was proportional to the total porosity (micropores and mesopores) of the CDC. The modifiable electromechanical response that arises from the precise porosity control attained through tailoring the CDC architecture demonstrates that these actuators hold great promise for smart, low-voltage-driven actuation devices.

  8. Tracing the origins of transient overshoots for binary mixture diffusion in microporous crystalline materials.

    Science.gov (United States)

    Krishna, Rajamani

    2016-06-21

    Separation of mixtures using microporous crystalline materials is normally achieved by exploiting differences in the adsorption strengths of the constituent species. The focus of the current investigation is on diffusion-selective separations that exploit differences in intra-crystalline diffusivities of guest molecules. A number of experimental investigations report overshoots in intra-crystalline loadings of the more mobile species during transient mixture uptake. Analogous overshoots in fluxes occur for mixture permeation across thin microporous membrane layers. The attainment of supra-equilibrium loadings is a common characteristic of diffusion-selective separations; this allows the over-riding of adsorption selectivities. The primary objective of the current investigation is to demonstrate that the Maxwell-Stefan diffusion formulation, using chemical potential gradients as driving forces, is capable of providing a quantitative description of the temporal and spatial overshoots found in diverse experimental studies. The origins of the overshoots can be traced to thermodynamic coupling effects that emanate from sizable off-diagonal contributions of the matrix of thermodynamic correction factors. If thermodynamic coupling effects are neglected, the overshoots are not realized. It is also demonstrated that while the transport of the more mobile partner is uphill of its loading gradient, its transport is downhill the gradient of its chemical potential. The deliberate exploitation of uphill diffusion to achieve difficult separations is highlighted.

  9. Boehmite particle coating modified microporous polyethylene membrane: A promising separator for lithium ion batteries

    Science.gov (United States)

    Yang, Chongwen; Tong, Hua; Luo, Chuanpeng; Yuan, Shuanglong; Chen, Guorong; Yang, Yunxia

    2017-04-01

    To exploit high-quality separators for lithium ion batteries, current research activities are mainly focused on the modification of microporous polyolefin membranes by coating them with inorganic particles to achieve comprehensive improvements in their thermal stability, electrochemical compatibility, and overcharge protection. Here, we report a separator made by coating boehmite (AlOOH) particles on microporous polyethylene (PE) membranes. Compared to the commercially applied coating materials, e.g., aluminum oxide (Al2O3), AlOOH allows for a substantial reduction in the coating thickness, while ensuring excellent thermal stability of the modified PE membrane. Our study shows that this is due to the formation of an interlocking interface structure that interconnects the PE membrane and AlOOH coating layer as soon as PE melts at about 140 °C, preventing the modified PE membrane from shrinking at subsequently elevated temperatures. The modified PE membrane exhibits suitable electrolyte wettability to facilitate ion transport through it. Thus, the lithium ion batteries employing it as a separator could attain substantially improved electrochemical performance. Furthermore, the AlOOH-coated PE separator was also found to provide an excellent overcharge protection.

  10. Three-dimensional microporous polypyrrole/polysulfone composite film electrode for supercapacitance performance

    Science.gov (United States)

    Feng, Xiaojuan; Shi, Yanlong; Jin, Shuping

    2015-10-01

    The three-dimensional microporous polypyrrole/polysulfone (PPY/PSF) composite film was fabricated via a simple polymerization method. The morphology structure and chemical composition of the composite film were characterized by scanning electron microscopy (SEM) and Fourier transform infrared spectroscopy (FTIR), respectively. The electrochemical properties of the composite film electrode were evaluated by cyclic voltammetry, galvanostatic charging-discharging and electrochemical impedance spectroscopy. The material exhibits excellent capacitance performance including high capacitance of 500 F g-1 at 0.3 A g-1 current density, good cycle stability in 800 continuous cycles (only 4.5% decay after 800 cycles at 0.3 A g-1), and low inter resistance. The good property of the PPY/PSF electrode should be attributed to its structural features, including two-layer microporous structure which facilitates the penetration of electrolytes into the inner surface, high surface area which provides more active sites. These results show that the composite film is a promising candidate for high energy electrochemical capacitors.

  11. Resistance to SO2 poisoning of V2O5/TiO2-PILC catalyst for the selective catalytic reduction of NO by NH3%氨法选择性还原氮氧化物 V2O5/TiO2-PILC催化剂的抗硫性能

    Institute of Scientific and Technical Information of China (English)

    臧思淼; 张桂臻; 邱文革; 宋丽云; 张然; 何洪

    2016-01-01

    A titania pillared interlayered clay (Ti‐PILC) supported vanadia catalyst (V2O5/TiO2‐PILC) was pre‐pared by wet impregnation for the selective catalytic reduction (SCR) of NO with ammonia. Com‐pared to the traditional V2O5/TiO2 and V2O5‐MoO3/TiO2 catalysts, the V2O5/TiO2‐PILC catalyst exhib‐ited a higher activity and better SO2 and H2O resistance in the NH3‐SCR reaction. Characterization using TPD, in situ DRIFT and XPS showed that surface sulfate and/or sulfite species and ionic SO42-species were formed on the catalyst in the presence of SO2. The ionic SO42-species on the catalyst surface was one reason for deactivation of the catalyst in SCR. The formation of the ionic SO42-spe‐cies was correlated with the amount of surface adsorbed oxygen species. Less adsorbed oxygen species gave less ionic SO42-species on the catalyst.%选择性催化还原(SCR)是目前去除氮氧化物最有效的方法之一. V2O5/TiO2催化剂被广泛应用于氨法选择性还原氮氧化物(NH3-SCR)反应,但该催化剂存在工作温度高(300–400oC)及 SO2氧化率高引起设备腐蚀和管路堵塞等问题,开发低温 SCR催化剂具有重要意义.过渡金属氧化物(如 Fe2O3, MnOx和 CuO等)催化剂用于低温SCR先后见诸文献报道,但这些催化剂在 SO2和 H2O存在下易失活.近年来柱撑黏土(PILC)引起科学家广泛关注, Yang等首次将 V2O5/TiO2-PILC催化剂应用于 NH3-SCR反应,发现其催化活性高于传统 V2O5/TiO2催化剂.柱撑黏土基催化剂在 NH3-SCR反应中也显示出良好抗硫性能,但 V2O5/TiO2-PILC催化剂的抗硫机理至今尚未见深入研究.因此我们制备了一系列 V2O5/TiO2-PILC催化剂,采用原位漫反射红外等方法详细研究了其抗硫性能较好的原因.  首先采用离子交换法制备出 TiO2-PILC载体,之后采用浸渍法制备了不同钒含量(质量分数x/%=0,3,4,5)的xV2O5/TiO2-PILC催化剂.同时,制备了传统 V2O5/TiO2和 V2O5-MoO3/TiO2催化剂作为

  12. The role of the nature of pillars in the structural and magnetic properties of magnetic pillared vlays

    DEFF Research Database (Denmark)

    Bachir, Cherifa; Lan, Yanhua; Mereacre, Valeriu;

    2011-01-01

    -PILCs, respectively) were produced at different calcination temperatures and then magnetic pillared clays (Ti-M-PILCs, Al-M-PILCs, and Zr-M-PILCs) were prepared at ambient temperature. The synthesis involves a reduction in aqueous solution of the original Fe-exchanged pillared clay using NaBH4. The structural...... properties of pillared clays and their magnetic forms were investigated using X-ray diffraction, N-2 adsorption, cation exchange capacity determination, and X-ray fluorescence (XRF) measurements. The properties of the magnetic pillared clays were investigated by superconducting quantum interference devices...

  13. Highly Luminescent Microporous Organic Polymer with Lewis Acidic Boron Sites on the Pore Surface: Ratiometric Sensing and Capture of F(-) Ions.

    Science.gov (United States)

    Suresh, Venkata M; Bandyopadhyay, Arkamita; Roy, Syamantak; Pati, Swapan K; Maji, Tapas Kumar

    2015-07-20

    Reversible and selective capture/detection of F(-) ions in water is of the utmost importance, as excess intake leads to adverse effects on human health. Highly robust Lewis acidic luminescent porous organic materials have potential for efficient sequestration and detection of F(-) ions. Herein, the rational design and synthesis of a boron-based, Lewis acidic microporous organic polymer (BMOP) derived from tris(4-bromo-2,3,5,6-tetramethylphenyl)boron nodes and diethynylbiphenyl linkers with a pore size of 1.08 nm for selective turn-on sensing and capture of F(-) ion are reported. The presence of a vacant pπ orbital on the boron center of BMOP results in intramolecular charge transfer (ICT) from the linker to boron. BMOP shows selective turn-on blue emission for F(-) ions in aqueous mixtures with a detection limit of 2.6 μM. Strong B-F interactions facilitate rapid sequestration of F(-) by BMOP. The ICT emission of BMOP can be reversibly regenerated by addition of an excess of water, and the polymer can be reused several times.

  14. Granular bamboo-derived activated carbon for high CO(2) adsorption: the dominant role of narrow micropores.

    Science.gov (United States)

    Wei, Haoran; Deng, Shubo; Hu, Bingyin; Chen, Zhenhe; Wang, Bin; Huang, Jun; Yu, Gang

    2012-12-01

    Cost-effective biomass-derived activated carbons with a high CO(2) adsorption capacity are attractive for carbon capture. Bamboo was found to be a suitable precursor for activated carbon preparation through KOH activation. The bamboo size in the range of 10-200 mesh had little effect on CO(2) adsorption, whereas the KOH/C mass ratio and activation temperature had a significant impact on CO(2) adsorption. The bamboo-derived activated carbon had a high adsorption capacity and excellent selectivity for CO(2) , and also the adsorption process was highly reversible. The adsorbed amount of CO(2) on the granular activated carbon was up to 7.0 mmol g(-1) at 273 K and 1 bar, which was higher than almost all carbon materials. The pore characteristics of activated carbons responsible for high CO(2) adsorption were fully investigated. Based on the analysis of narrow micropore size distribution of several activated carbons prepared under different conditions, a more accurate micropore range contributing to CO(2) adsorption was proposed. The volume of micropores in the range of 0.33-0.82 nm had a good linear relationship with CO(2) adsorption at 273 K and 1 bar, and the narrow micropores of about 0.55 nm produced the major contribution, which could be used to evaluate CO(2) adsorption on activated carbons.

  15. Microporous hollow fibre membrane modules as gas-liquid contactors. Part 1. Physical mass transfer processes : A specific application

    NARCIS (Netherlands)

    Kreulen, H.; Versteeg, G.F.; Swaaij, W.P.M. van

    1993-01-01

    Gas-liquid mass transfer has been studied in a membrane module with non-wetted microporous fibres in the laminar flow regime. This new type of gas/liquid contactor can be operated stabily over a large range of gas and liquid flows because gas and liquid phase do not influence each other directly. Th

  16. Effect of adsorption of charged macromolecules on streaming and membrane potential values measured with a microporous polysulfone membrane

    DEFF Research Database (Denmark)

    Benavente, J.; Jonsson, Gunnar Eigil

    1997-01-01

    Changes in streaming and membrane potentials measured across a commercial microporous polysulfone membrane as a result of the adsorption of differently charged macromolecules were studied. Measurements were carried out with different NaCl solutions (10(-3) M to 5 x 10(-2) M) and their mixtures...

  17. Microporous hollow fibre membrane modules as gas-liquid contactors. Part 1. Physical mass transfer processes : A specific application

    NARCIS (Netherlands)

    Kreulen, H.; Versteeg, G.F.; Swaaij, W.P.M. van

    1993-01-01

    Gas-liquid mass transfer has been studied in a membrane module with non-wetted microporous fibres in the laminar flow regime. This new type of gas/liquid contactor can be operated stabily over a large range of gas and liquid flows because gas and liquid phase do not influence each other directly.

  18. Preparation of mesohollow and microporous carbon nanofiber and its application in cathode material for lithium–sulfur batteries

    Energy Technology Data Exchange (ETDEWEB)

    Wu, Yuanhe; Gao, Mingxia, E-mail: gaomx@zju.edu.cn; Li, Xiang; Liu, Yongfeng; Pan, Hongge, E-mail: hgpan@zju.edu.cn

    2014-09-01

    Highlights: • Mesohollow and microporous carbon fibers were prepared via electrospinning and carbonization. • Sulfur (S) incorporated into the porous fibers by thermal heating in 60 wt.%, forming composite. • S fills fully in the micropores and partially in the mesohollows of the carbon fibers. • The composite shows high capacity and capacity retention as cathode material for Li–S batteries. • Mesohollow and microporous structure is effective in improving the property of S cathode. - Abstract: Mesohollow and microporous carbon nanofibers (MhMpCFs) were prepared by a coaxial electrospinning with polyacrylonitrile (PAN) and polymethylmethacrylate (PMMA) as outer and inner spinning solutions followed by a carbonization. The carbon fibers were thermal treated with sublimed sulfur to form S/MhMpCFs composite, which was used as cathode material for lithium–sulfur batteries. Electrochemical study shows that the S/MhMpCFs cathode material provides a maximum capacity of 815 mA h/g after several cycles of activation, and the capacity retains 715 mA h/g after 70 cycles, corresponding to a retention of 88%. The electrochemical property of the S/MhMpCFs composite is much superior than the S-incorporated solid carbon fibers prepared from electrospinning of single PAN. The mechanism of the enhanced electrochemical property of the S/MhMpCFs composite is discussed.

  19. Rapid biofabrication of tubular tissue constructs by centrifugal casting in a decellularized natural scaffold with laser-machined micropores.

    Science.gov (United States)

    Kasyanov, Vladimir A; Hodde, Jason; Hiles, Michael C; Eisenberg, Carol; Eisenberg, Leonard; De Castro, Luis E F; Ozolanta, Iveta; Murovska, Modra; Draughn, Robert A; Prestwich, Glenn D; Markwald, Roger R; Mironov, Vladimir

    2009-01-01

    Centrifugal casting allows rapid biofabrication of tubular tissue constructs by suspending living cells in an in situ cross-linkable hydrogel. We hypothesize that introduction of laser-machined micropores into a decellularized natural scaffold will facilitate cell seeding by centrifugal casting and increase hydrogel retention, without compromising the biomechanical properties of the scaffold. Micropores with diameters of 50, 100, and 200 mum were machined at different linear densities in decellularized small intestine submucosa (SIS) planar sheets and tubular SIS scaffolds using an argon laser. The ultimate stress and ultimate strain values for SIS sheets with laser-machined micropores with diameter 50 mum and distance between holes as low as 714 mum were not significantly different from unmachined control SIS specimens. Centrifugal casting of GFP-labeled cells suspended in an in situ cross-linkable hyaluronan-based hydrogel resulted in scaffold recellularization with a high density of viable cells inside the laser-machined micropores. Perfusion tests demonstrated the retention of the cells encapsulated within the HA hydrogel in the microholes. Thus, an SIS scaffold with appropriately sized microholes can be loaded with hydrogel encapsulated cells by centrifugal casting to give a mechanically robust construct that retains the cell-seeded hydrogel, permitting rapid biofabrication of tubular tissue construct in a "bioreactor-free" fashion.

  20. Core-shell conjugated microporous polymers: a new strategy for exploring color-tunable and -controllable light emissions.

    Science.gov (United States)

    Xu, Yanhong; Nagai, Atsushi; Jiang, Donglin

    2013-02-25

    A core-shell strategy is demonstrated for designing a conjugated microporous polymer that allows the tuning of light emission over a wide wavelength range in a controlled manner. The polymers not only emit efficiently with an eight-fold enhanced luminescence but also sustain light emissions, irrespective of solvent and state.

  1. Sulfur loaded in micropore-rich carbon aerogel as cathode of lithium-sulfur battery with improved cyclic stability

    Science.gov (United States)

    Li, Zihao; Li, Xiaogang; Liao, Youhao; Li, Xiaoping; Li, Weishan

    2016-12-01

    We report a novel composite of sulfur loaded in micropore-rich carbon aerogel (CA-S), as cathode of lithium-sulfur battery. Carbon aerogel (CA) is synthesized through phenol-formaldehyde reaction with a low catalyst concentration and carbonization under high temperature, and loaded with sulfur via chemical deposition and heat treatment. The physical properties of the resulting CA and the electrochemical performances of the resulting CA-S are investigated by scanning electron microscopy, thermal gravimetric analysis, Brunauer-Emmett-Teller characterization, electrochemical impedance spectroscopy, and galvanostatic discharge/charge test, with a comparison of a common carbon material, acetylene black (AB), and sulfur loaded in AB (AB-S). It is found that the CA is micropore-rich with micropore volume over 66% of total pore volume, and the CA-S exhibits significantly improved cyclic stability compared with AB-S. The improved performance of CA-S is attributed to the confinement of the micropores in CA to small sulfur allotropes and corresponding lithium sulfides.

  2. The role of sulfur trapped in micropores in the catalytic partial oxidation of hydrogen sulfide with oxygen

    NARCIS (Netherlands)

    Steijns, M.; Mars, P.

    1974-01-01

    The catalytic oxidation of hydrogen sulfide into sulfur with molecular oxygen has been studied in the temperature range 130–200 °C. Active carbon, molecular sieve 13X and liquid sulfur were used as catalysts. Sulfur is adsorbed in the micropores (3 < r < 40 Å) of the catalysts. Experiments with a su

  3. Ultra-Small MgH2 Nanoparticles Embedded Into an Ordered Microporous Carbon Showing Rapid Hydrogen Sorption Kinetics

    NARCIS (Netherlands)

    Zlotea, C.; Oumellal, Y.; Hwang, S-J; Ghimbeu, C.M.; de Jongh, Petra; Latroche, M.

    2015-01-01

    MgH2 nanoparticles with different average sizes have been prepared into an ordered microporous carbon by tuning the Mg amount from 15 to 50 wt%. Ultra-small particles with mean size of 1.3 and 3.0 nm have been obtained for 15 and 25wt% Mg content, respectively. The hydrogen desorption properties str

  4. Template-Free Synthesis of Hierarchical Porous Metal-Organic Frameworks

    Energy Technology Data Exchange (ETDEWEB)

    Yue, Yanfeng [ORNL; Qiao, Zhen-an [University of Tennessee, Knoxville (UTK); Fulvio, Pasquale F [ORNL; Dai, Sheng [ORNL; Binder, Andrew J [ORNL; Tian, Chengcheng [ORNL; Nelson, Kimberly M [ORNL; Zhu, Xiang [ORNL

    2013-01-01

    A template-free synthesis of a hierarchical microporous-mesoporous metal-organic framework (MOF) of Zn(II)-2,5-dihydroxy-1,4-benzenedicarboxylate, namely Zn-MOF-74, is reported. The surface morphology and porosity of the bimodal materials can be modified by etching the pore walls with the synthesis solvent under different reaction times and different solvents. This template-free strategy allows for the preparation of stable frameworks with mesopores exceeding 15 nm, which was previously unattained by the synthesis of MOFs by ligand exten-sion method.

  5. Non-isothermal two-phase transport in the polymer electrolyte membrane fuel cell microporous layer

    Science.gov (United States)

    Ge, Nan

    This thesis investigates the water transport mechanisms in the crack-free microporous layer (MPL) of a polymer electrolyte membrane (PEM) fuel cell. Synchrotron X-ray radiography was used to visualize and quantify the in situ liquid water in the gas diffusion layers (GDLs) of an operating fuel cell. A methodology was developed to correct the artefact of imaging sample movement. Furthermore, to address inaccuracies due to the scattering effect and higher harmonics at the synchrotron beamline, a calibration technique was introduced in order to experimentally determine the liquid water X-ray attenuation coefficient. Through in situ radiography, liquid water breakthrough events were observed in the MPL, and measured water thicknesses were used as inputs into a one-dimensional (1D) heat and mass transport model. The 1D model was used to describe the coupled relationship between liquid and vapour transport through the cathode MPL and the temperature distributions in the operating fuel cell.

  6. UV-Visible and Plasmonic Nanospectroscopy of the CO2 Adsorption Energetics in a Microporous Polymer.

    Science.gov (United States)

    Nugroho, Ferry A A; Xu, Chao; Hedin, Niklas; Langhammer, Christoph

    2015-10-20

    In the context of carbon capture and storage (CCS), micro- and mesoporous polymers have received significant attention due to their ability to selectively adsorb and separate CO2 from gas streams. The performance of such materials is critically dependent on the isosteric heat of adsorption (Qst) of CO2 directly related to the interaction strength between CO2 and the adsorbent. Here, we show using the microporous polymer PIM-1 as a model system that its Qst can be conveniently determined by in situ UV-vis optical transmission spectroscopy directly applied on the adsorbent or, with higher resolution, by indirect nanoplasmonic sensing based on localized surface plasmon resonance in metal nanoparticles. Taken all together, this study provides a general blueprint for efficient optical screening of micro- and mesoporous polymeric materials for CCS in terms of their CO2 adsorption energetics and kinetics.

  7. Surface texture and percolation effects in microporous oriented films of polyolefins

    Science.gov (United States)

    Novikov, D. V.; Kuryndin, I. S.; Bukošek, V.; Elyashevich, G. K.

    2012-11-01

    The surface structure of polypropylene and polyethylene microporous films prepared by the extrusion of the polymer melt with the subsequent stages of annealing, uniaxial extension, and thermal fixation of the samples has been analyzed using scanning electron microscopy. It has been shown that percolation through pores corresponds to the axial texture of the surface with the channel structure described by the fractal cluster model. The transition from open pores (through-flow channels) to closed pores leads to the formation of surface regions with a biaxial texture. An increase in the density of the solid phase cluster is accompanied by the formation of a homogeneous biaxial texture with a period of alternation of the density in two mutually perpendicular directions, one of which coincides with the direction of orientation of the films.

  8. Microporous layer based on SiC for high temperature proton exchange membrane fuel cells

    Science.gov (United States)

    Lobato, Justo; Zamora, Héctor; Cañizares, Pablo; Plaza, Jorge; Rodrigo, Manuel Andrés

    2015-08-01

    This work reports the evaluation of Silicon Carbide (SiC) for its application in microporous layers (MPL) of HT-PEMFC electrodes and compares results with those obtained using conventional MPL based on Vulcan XC72. Influence of the support load on the MPL prepared with SiC was evaluated, and the MPL were characterized by XRD, Hg porosimetry and cyclic voltammetries. In addition, a short lifetest was carried out to evaluate performance in accelerated stress conditions. Results demonstrate that SiC is a promising alternative to carbonaceous materials because of its higher electrochemical and thermal stability and the positive effect on mass transfer associated to its different pore size distribution. Ohmic resistance is the most significant challenge to be overcome in further studies.

  9. Laser Control of Self-Organization Process in Microscopic Region and Fabrication of Fine Microporous Structure

    Directory of Open Access Journals (Sweden)

    Yukimasa Matsumura

    2012-01-01

    Full Text Available We present a controlling technique of microporous structure by laser irradiation during self-organization process. Self-organization process is fabrication method of microstructure. Polymer solution was dropped on the substrate at high humid condition. Water in air appears dropping air temperature below the dew point. The honeycomb structure with regularly aligned pores on the film was fabricated by attaching water droplets onto the solution surface. We demonstrate that it was possible to prevent forming pores at the region of laser irradiation and flat surface was fabricated. We also demonstrated that a combination structure with two pore sizes and flat surface was produced by a single laser-pulse irradiation. Our method is a unique microfabrication processing technique that combines the advantages of bottom-up and top-down techniques. This method is a promising technique that can be applied to produce for photonic crystals, biological cell culturing, surface science and electronics fields, and so forth.

  10. Ionic transport in P(VdF–HFP)–PEO based novel microporous polymer electrolytes

    Indian Academy of Sciences (India)

    M Deka; A Kumar

    2009-12-01

    A novel microporous polymer electrolyte (MPE) comprising blends of poly(vinylidene fluoride-cohexafluoropropylene) [P(VdF–HFP)] and polyethylene oxide (PEO) was prepared by phase inversion technique. It was observed that addition of PEO improved the pore configuration, such as pore size, pore connectivity and porosity of P(VdF–HFP) based membranes. The room temperature ionic conductivity was significantly enhanced. The highest porosity of about 65% and ionic conductivity of about 7 × 10-4 S cm-1 was obtained when the weight ratio of PEO was 40%. The liquid electrolyte uptake was found to increase with increase in porosity and pore size. However, at higher weight ratio of PEO (> 40%) porosity, pore size and ionic conductivity was decreased. This descending trend with further increase of PEO weight ratio was attributed to conglomeration effect of PEO at the pores.

  11. Thermochemistry of organic reactions in microporous oxides by atomistic simulations: benchmarking against periodic B3LYP.

    Science.gov (United States)

    Bleken, Francesca; Svelle, Stian; Lillerud, Karl Petter; Olsbye, Unni; Arstad, Bjørnar; Swang, Ole

    2010-07-15

    The methylation of ethene by methyl chloride and methanol in the microporous materials SAPO-34 and SSZ-13 has been studied using different periodic atomistic modeling approaches based on density functional theory. The RPBE functional, which earlier has been used successfully in studies of surface reactions on metals, fails to yield a qualitatively correct description of the transition states under study. Employing B3LYP as functional gives results in line with experimental data: (1) Methanol is adsorbed more strongly than methyl chloride to the acid site. (2) The activation energies for the methylation of ethene are slightly lower for SSZ-13. Furthermore, the B3LYP activation energies are lower for methyl chloride than for methanol.

  12. A microporous Zn(II)-MOF with open metal sites: structure and selective adsorption properties.

    Science.gov (United States)

    Zheng, Xiaofang; Huang, Yumei; Duan, Jingui; Wang, Chenggang; Wen, Lili; Zhao, Jinbo; Li, Dongfeng

    2014-06-14

    A three-dimensional microporous framework, Zn(II)-MOF [Zn(HPyImDC)(DMA)]n (1) (H3PyImDC = 2-(pyridine-4-yl)-1H-4,5-imidazoledicarboxylic, DMA = N,N'-dimethylacetamide), with open metal sites and small-sized pores, exhibits excellent selective capture of CO2 over N2 and CH4 at 273 K, as well as alcohols from water. The excellent CO2 adsorption selectivity of 1 allows its potential use in the capture of CO2 from industrial flue gas or the removal of CO2 from natural gas. More interestingly, compound represents the rare case of porous materials separating propanol isomers, which may be caused by the relative flexibility of the linear n-propanol considering that both n-propanol and i-propanol have similar kinetic diameters.

  13. PREPARATION AND CHARACTERIZATION OF PVDF-HFP MICROPOROUS MEMBRANE BY TEMPLATE METHOD

    Institute of Scientific and Technical Information of China (English)

    Jian-hua Cao; Bao-ku Zhu; You-yi Xu

    2006-01-01

    Porous poly(vinylidene fluoride-co-hexafluoropropylene) (PVDF-HFP) membranes were successfully prepared using dibutyl phthalate (DBP), polyvinylpyrrolidone (PVP-K30), polyethylene glycol 200 (PEG200) as templates. SEM was used to examine the morphology of the PVDF-HFP porous membranes. It was found that these membranes have an asymmetric structure and the blends of PVDF-HFP/DBP formed nanoporous membranes, whereas the blends of PVDF-HFP/PVP-K30 formed "sponge-like" and microporous membranes. Moreover, the average pore size and porosity was about 0.3 μm and 48.7%, respectively. The crystallinity, thermal stability and mechanical strength of membranes were characterized by XRD, DSC, TGA and stress-strain tests. The results showed that the membranes are α crystals with excellent thermal stability. It was an effective way to regulate pore size and morphology of the PVDF-HFP membranes.

  14. Water distillation with microporous membrane; Destilacion de agua con membranas microporosas por pervaporacion

    Energy Technology Data Exchange (ETDEWEB)

    Odicino, I. A.; Perello, D.; Follari, J.; Lesino, G.

    2004-07-01

    We develop a distillation cell that uses for their operation a microporous membrane manufactured in the laboratories of chemistry of our university. This membrane is made of polisulfona . We use like force instigator the difference of concentration of vapor generated by the temperature in the side of the feeding and in another end of the pore for the load of absolute humidity that has under the environmental conditions the air that is used as haulage gas. We carry out experimentations under controlled conditions of laboratory and we compare the experimental data with the theoretical values. The experimental results are highly consistent with the developed theory, and they allow to propose a compact cell design to build. (Author)

  15. Light Hydrocarbons Adsorption Mechanisms in Two Calcium-based Microporous Metal Organic Frameworks

    KAUST Repository

    Plonka, Anna M.

    2016-01-25

    The adsorption mechanism of ethane, ethylene and acetylene (C2Hn; n=2, 4, 6) on two microporous metal organic frameworks (MOFs) is described here that is consistent with observations from single crystal and powder X-ray diffraction, calorimetric measurments and gas adsorption isotherm measurements. Two calcium-based MOFs, designated as SBMOF-1 and SBMOF-2 (SB: Stony Brook), form three-dimensional frameworks with one-dimensional open channels. As determined form single crystal diffraction experiments channel geometries of both SBMOF-1 and SBMOF-2 provide multiple adsorption sites for hydrocarbon molecules trough C-H…π and C-H…O interactions, similarly to interactions in the molecular and protein crystals. Both materials selectively adsorb C2 hydrocarbon gases over methane as determined with IAST and breakthrough calculations, with C2H6/CH4 selectivity as high as 74 in SBMOF-1.

  16. Novel thiophene-bearing conjugated microporous polymer honeycomb-like porous spheres with ultrahigh iodine uptake.

    Science.gov (United States)

    Ren, Feng; Zhu, Zhaoqi; Qian, Xin; Liang, Weidong; Mu, Peng; Sun, Hanxue; Liu, Jiehua; Li, An

    2016-07-28

    Two conjugated microporous polymers containing thiophene-moieties (SCMPs) were obtained by the polymerization of 3,3',5,5'-tetrabromo-2,2'-bithiophene and ethynylbenzene monomers through the palladium-catalyzed Sonogashira-Hagihara crosscoupling reaction. The resulting SCMPs show high thermal stability with a decomposition temperature above 300 °C. Scanning electron microscopy images show that the resulting SCMPs formed as an aggregation composed of micrometer-sized SCMP spheres, in which honeycomb-like porous spheres with penetrated pores on the surface were observed. Taking advantage of such a unique honeycomb-like porous morphology as well as π-conjugated structures, the SCMPs show ultrahigh absorption performance for iodine vapour with an uptake of up to 345 wt% obtained, which is the highest value reported to date for CMPs, thus making the resulting SCMPs ideal absorbent materials for reversible iodine capture to address environmental issues.

  17. New Microporous Polymer Electrolyte Based on Polysiloxane Grafted with Imidazolium Iodide Moieties for DSSC

    Directory of Open Access Journals (Sweden)

    Yan Yang

    2011-01-01

    Full Text Available Two types of polysiloxane grafted with different ratio of imidazolium iodide moieties (IL-SiO2 have been synthesized to develop a micro-porous polymer electrolyte for quasi-solid-state dye-sensitized solar cells. The samples were characterized by 1HNMR, FT-IR spectrum, XRD, TEM and SEM, respectively. Moreover, the ionic conductivity of the electrolytes was measured by electrochemical workstation. Nanostructured polysiloxane containing imidazolium iodide showed excellent compatibility with organic solvent and polymer matrix for its ionic liquid characteristics. Increasing the proportion of imidazolium iodide moieties in polysiloxane improved the electrochemical behavior of the gel polymer electrolyte. A dye-sensitized solar cell with gel polymer electrolyte yielded an open-circuit voltage of 0.70 V, short-circuit current of 11.19 mA cm−2, and the conversion efficiency of 3.61% at 1 sun illumination.

  18. Effect of nanoparticle coating on the thermal conductivity of microporous thermal insulations.

    Science.gov (United States)

    Lee, Dong-Bok; Kwon, Hyuk-Chon; Kim, Yun-Il; Park, Sung; Lee, Jae Chun; Misture, Scott

    2010-05-01

    Microporous thermal insulations were prepared from mixtures of nano-sized fumed silica, micron-sized fibers and opacifier particles. Those micron-sized particles were dry coated with nano-sized fumed silica particles by mechanical process using a compressive-shear type mill. The effect of nanoparticle coating on the thermal conductivity of the insulation media was investigated using a hot-wire method. Effect of nanoparticle coating was found to be more pronounced for the insulation composed of fumed silica and fiber than for the one composed of fumed silica, fiber and an opacifier. By adding 15% SiC or TiO2 opacifier, the thermal conductivity of the insulation samples could be lowered to 0.08 Wm(-1) K(-1) at temperature range of 805 approximately 817 degrees C. The temperature dependent thermal conductivity of the sample containing glass fiber did not exhibit any remarkable changes compared to the one containing ceramic fiber.

  19. Ab initio study of adsorption of molecular hydrogen on microporous metal-organic frameworks.

    Science.gov (United States)

    Hamel, Sébastien; Côté, Michel

    2004-03-01

    In the ongoing search for promising compounds for hydrogen storage, novel porous metal-organic frameworks (MOF) have been discovered recently [1]. Well defined binding sites were deduced from inelastic neutron scattering (INS) spectroscopy of the rotational transitions of the adsorbed molecular hydrogen. In light of this discovery we performed ab initio density functional theory (DFT) calculations of the adsorption of molecular hydrogen on this class of microporous MOF to compare different adsorption sites. Different approximations for the exchange-correlation potentials were accessed for a set of relevant properties such as binding energy, energetically favored configuration and distance between the adsorbents and adsorbates. In particular, theoretical rotational spectra of the adsorbed H2 were obtained that could be compared to the experimental INS spectra. [1] Rosi et al., Science Vol. 300, 1127 (2003)

  20. FABRICATION OF MICROPOROUS SILICA CERAMICS WITH VARIED POLYMORPHIC FORMS AND INVESTIGATION OF THEIR THERMAL SHOCK BEHAVIOUR

    Directory of Open Access Journals (Sweden)

    Osman ŞAN

    2011-06-01

    Full Text Available In this study; the SiO₂ micro-porous ceramics in the phase α-quartz, α-cristobalite and β-cristobalite were produced and thermal shock resistance of products were compared. In the production of ceramic materials; α-quartz obtained from natural quartz powder, α-cristobalite from pure silica powder which prepared by Stöber technique and β-cristobalite from sol-gel approach. The β-composition was designed as Si₁₋⨯Al⨯Ca⨯/₂O₂ where x=0.05 and obtained gel was calcined at 850 °C. Before shaping, α-quartz powder and calcined β-cristobalite powder were grind in the planetary mill and the powder produced by Stöber technique was shaped directly without any milling process. The prepared powders were shaped by uniaxally press at 50 bars. The samples produced from α-quartz and β-cristobalite powders were sintered at 1150 °C and α-cristobalite obtained by Stöber technique was sintered at 1400 °C. In the defined polymorphic structure, micro-porous materials with pore size ~0.1-5 µm were produced and thermal shock tests were applied. Irrespective of β-cristobalite material, the samples were cracked and the tests could only repeat on the samples with β-cristobalite material. In the result, the β-cristobalite sample is believed to be great potential to use as a membrane filters for harsh thermal environments.

  1. Functionalized PCL/HA nanocomposites as microporous membranes for bone regeneration

    Energy Technology Data Exchange (ETDEWEB)

    Basile, Maria Assunta; Gomez d' Ayala, Giovanna; Malinconico, Mario [Institute for Polymers, Composites and Biomaterials, CNR, Via Campi Flegrei 34, Pozzuoli (Naples) (Italy); Laurienzo, Paola, E-mail: paola.laurienzo@ipcb.cnr.it [Institute for Polymers, Composites and Biomaterials, CNR, Via Campi Flegrei 34, Pozzuoli (Naples) (Italy); Coudane, Jean; Nottelet, Benjamin [Institut des Biomolécules Max Mousseron (IBMM), Artificial Biopolymers Group, CNRS UMR 5247, University of Montpellier 1, Faculty of Pharmacy, 15 Av. C. Flahault, Montpellier 34093 (France); Ragione, Fulvio Della [Department of Biochemistry and Biophysics, Second University of Naples, Via L. De Crecchio 7, Naples (Italy); Oliva, Adriana, E-mail: adriana.oliva@unina2.it [Department of Biochemistry and Biophysics, Second University of Naples, Via L. De Crecchio 7, Naples (Italy)

    2015-03-01

    In the present work, microporous membranes based on poly(ε-caprolactone) (PCL) and PCL functionalized with amine (PCL-DMAEA) or anhydride groups (PCL-MAGMA) were realized by solvent–non solvent phase inversion and proposed for use in Guided Tissue Regeneration (GTR). Nanowhiskers of hydroxyapatite (HA) were also incorporated in the polymer matrix to realize nanocomposite membranes. Scanning Electron Microscopy (SEM) showed improved interfacial adhesion with HA for functionalized polymers, and highlighted substantial differences in the porosity. A relationship between the developed porous structure of the membrane and the chemical nature of grafted groups was proposed. Compared to virgin PCL, hydrophilicity increases for functionalized PCL, while the addition of HA influences significantly the hydrophilic characteristics only in the case of virgin polymer. A significant increase of in vitro degradation rate was found for PCL-MAGMA based membranes, and at lower extent of PCL-DMAEA membranes. The novel materials were investigated regarding their potential as support for cell growth in bone repair using multipotent mesenchymal stromal cells (MSC) as a model. MSC plated onto the various membranes were analyzed in terms of adhesion, proliferation and osteogenic capacity that resulted to be related to chemical as well as porous structure. In particular, PCL-DMAEA and the relative nanocomposite membranes are the most promising in terms of cell-biomaterial interactions. - Graphical abstract: Functionalized PCL is used to realize nanocomposites with hydroxyapatite (HA) in the form of microporous membranes. The influence of different grafted groups on mechanical properties, in vitro degradation, porous membrane structure and interaction with mesenchymal stromal cells (MSC) is discussed. - Highlights: • Functionalized PCL shows faster in vitro degradation rate. • Functionalized PCL shows superior cell adhesion, proliferation and differentiation. • Nanocomposites based

  2. Effect of microporation on passive and iontophoretic delivery of diclofenac sodium.

    Science.gov (United States)

    Patel, Hiren; Joshi, Abhay; Joshi, Amit; Stagni, Grazia

    2015-01-01

    Skin pretreatment with a microneedle roller (microporation (MP)) appears a simple and inexpensive technique to increase transdermal delivery of topically applied drug products. This study investigates the effect of MP on the passive and iontophoretic delivery of diclofenac (DCF) by quantifying dermis and plasma levels of DCF in a rabbit model. New Zealand albino female rabbits received either: (i) a topical application of 4 g of Voltaren® 1% gel with or without pretreatment with a microroller (0.5 mm needle length; density 23 microneedles per cm(2) area) or (ii) a DCF solution (40 mg/2.5 mL) via iontophoresis (IOMED transQ(E) medium size patch), with or without microroller pretreatment. A 300 µA/cm(2) cathodic current was applied for 20 min for a total of 80 mA. DCF concentrations were monitored in dermis with microdialysis sampling every 20 min for 5 h. Plasma samples were collected over the same period. In the passive delivery studies, microroller pretreatment increased Cmax by 1.5- and 2.0-fold in skin and plasma, respectively, and AUC by 1.5- and 2.4-fold in skin and plasma, respectively. In the iontophoresis delivery studies, microporation increased Cmax by 2.0-fold both in skin and in plasma, and AUC by 1.1- and 1.8-fold in skin and plasma, respectively. In conclusion, microneedle pretreatment increased significantly the systemic exposure of DCF from either passive or iontophoretic delivery, whereas the effect in skin was less pronounced.

  3. Gas separation using sol-gel derived microporous zirconia membranes with high hydrothermal stability☆

    Institute of Scientific and Technical Information of China (English)

    Li Li; Hong Qi

    2015-01-01

    A microporous zirconia membrane with hydrogen permeance about 5 × 10−8 mol·m−2·s−1·Pa−1, H2/CO2 permselectivity of ca. 14, and excellent hydrothermal stability under steam pressure of 100 kPa was fabricated via polymeric sol–gel process. The effect of calcination temperature on single gas permeance of sol–gel derived zirconia membranes was investigated. Zirconia membranes calcined at 350 °C and 400 °C showed similar single gas permeance, with permselectivities of hydrogen towards other gases, such as oxygen, nitrogen, methane, and sulfur hexafluoride, around Knudsen values. A much lower CO2 permeance (3.7 × 10−9 mol·m−2·s−1·Pa−1) was observed due to the interaction between CO2 molecules and pore wall of membrane. Higher calcination tem-perature, 500 °C, led to the formation of mesoporous structure and, hence, the membrane lost its molecular siev-ing property towards hydrogen and carbon dioxide. The stability of zirconia membrane in the presence of hot steam was also investigated. Exposed to 100 kPa steam for 400 h, the membrane performance kept unchanged in comparison with freshly prepared one, with hydrogen and carbon dioxide permeances of 4.7 × 10−8 and~3 × 10−9 mol·m−2·s−1·Pa−1, respectively. Both H2 and CO2 permeances of the zirconia membrane de-creased with exposure time to 100 kPa steam. With a total exposure time of 1250 h, the membrane presented hydrogen permeance of 2.4 × 10−8 mol·m−2·s−1·Pa−1 and H2/CO2 permselectivity of 28, indicating that the membrane retains its microporous structure.

  4. Effect of sol size on nanofiltration performance of a sol-gel derived microporous zirconia membrane

    Institute of Scientific and Technical Information of China (English)

    Guizhi Zhu; Qian Jiang; Hong Qi; Nanping Xu

    2015-01-01

    This paper reports the effect of sol size on nanofiltration performances of sol–gel derived microporous zirconia membranes. Microstructure, pure water flux, molecular weight cut-off (MWCO) and salt retention of zirconia membranes derived from zirconia sols with different sizes were characterized. Thermal evolution, phase compo-sition, microstructure and chemical stability of unsupported zirconia membranes (powder) were determined by thermogravimetric and differential thermal analysis, X-ray diffraction, nitrogen adsorption–desorption and static solubility measurements. Results show that nanofiltration performance of zirconia membranes is highly depen-dent on sol size. The sol with an average size of 3.8 nm, which is smaller than the pore size of theγ-Al2O3 support (pore size:5–6 nm), forms a discontinuous zirconia separation layer because of excessive penetration of sol into the support. This zirconia membrane displays a MWCO value towards polyethylene glycol higher than 4000 Da. A smooth and defect-free zirconia membrane with a MWCO value of 1195 Da (pore size:1.75 nm) and relative high retention rates towards MgCl2 (76%) and CaCl2 (64%) was successfully fabricated by dip-coating the sol with an appropriate size of 8.6 nm. Zirconia sol with an average size of 12 nm exhibits colloidal nature and forms a zirconia membrane with a MWCO value of 2332 Da (pore size:2.47 nm). This promising microporous zirconia membrane presents sufficiently high chemical stability in a wide pH range of 1–12.

  5. Effects of alkali metals on catalyst of MnOx-CeO2/ZrO2-PILC in the low-temperature selective catalytic reduction%碱土金属对MnOx-CeO2/ZrO2-PILC催化剂SCR活性影响研究

    Institute of Scientific and Technical Information of China (English)

    沈伯雄; 陈建宏; 姚燕; 胡国丽

    2012-01-01

    The poisoning effects of alkali metals on low-temperature selective catalytic reduction (SCR) catalyst MnOx-CeO2/ZrO2-PILC were invested by the method of impregnation in the laboratory. It was indicated that the addition of Ca/Mg would decrease the activities of the catalyst, and the poisoning effects were contacted with the amount and acidity of the doped-alkali metal. X-ray diffraction (XRD) , H2-temperature programmed reduction (H2-TPR) , N2 adsorption-desorption and temperature-programmed desorption of NH3(NH3-TPD) were used to characterize the properties of the fresh and alkali earth doped catalysts. According to the results, the doped-alkali metals would inhibit the reduction properties, induce the loss in surface area and surface acidity.%采用浸渍法模拟低温选择性催化还原(SCR)催化剂MnOx-CeO2/ZrO2-PILC的碱土金属中毒特性,研究了碱土金属及其负载量对中毒程度的影响.实验表明,钙/镁的添加会引起催化剂中毒,催化剂中毒失活程度与碱土金属的负载量有关.运用X射线衍射(XRD)、H2程序升温还原(H2-TPR)、氮气吸脱附及NH3程序升温脱附(NH3-TPD)对新鲜催化剂以及碱土金属中毒后的催化剂进行了表征.结果表明,钙/镁中毒后催化剂的比表面积降低、催化剂氧化还原性和表面酸性减少,进而造成催化剂失活.

  6. Synthesis and Gas Sorption Properties of Cupric Microporous Metal-Organic Framework Based on 1,1'-Ethynebenzene-3,3',5,5'-tetracarboxylate%基于1,1′-二苯乙炔-3,3′,5,5′-四羧酸微孔铜配位聚合物的合成和气体吸附性质

    Institute of Scientific and Technical Information of China (English)

    胡云霞; 章文伟; 王立锋; 白俊峰

    2013-01-01

    The synthesis,crystal structure,and sorption properties of[Cu2(EBTC)(H2O)2]·8H2O·DMF·DMSO (abbreviated as 1,EBTC =1,1'-ethynebenzene-3,3',5,5'-tetracarboxylate; DMF=N,N-dimethyl formamide; DMSO =dimethyl sulfoxide) are reported.1 features two kinds of cavities with a diameter of 0.85 nm and 0.85×2.15 nm,which are enclosed respectively by six and twelve tetracarboxylate-bridged [Cu2(CO2)4] paddle-wheels and extended by the EBTC linkers into a three-dimensional (3D) supramolecular structure with 1D channels accommodating the solvent molecules.It adopts the (3,4)-c net of fof (sqc 1575) topology,possesses very large solvent accessible pore volume which reaches 72.8% of the unit cell volume.After removal of the solvent molecules,the desolvated 1a exhibits permanent porosity verified by an N2 sorption isotherm with a Langmuir surface area of 2844 m2·g-1 and Brunauer-Emmett-Teller (BET) surface area of 1 852 m2· g-1.It displays significant uptake of gases (H2,CO2,CH4,C2H2) and relatively high adsorption enthalpies.Especially,it is notable that 1a exhibits the highest acetylene storage of 252 cm3·g-1 at 273 K under 1.0×105 Pa with higher adsorption enthalpy (34.5 kJ ·mol-1 at the coverage of 1 mmol·g-1) among all porous metal-organic materials reported to date.CCDC:744108.%本文报道了配合物[Cu2(EBTC)(H2O)2]· 8H2O· DMF· DMSO(1,EBTC=1,1′-二苯乙炔-3,3′,5,5′-四羧酸根;DMF=N,N-二甲基甲酰胺;DMSO=二甲基亚砜)的合成、晶体结构和吸附性质.1拥有内径为0.85 nm和0.85 nm×2.15 nm的两种孔洞,分别被6个和12个四羧酸根桥联的[Cu2(CO2)4]螺旋桨式结构围绕,并被EBTC连接成三维超分子结构,该结构拥有可容纳溶剂分子的一维孔道.1为(3,4)-连接的fof(sqc 1575)拓扑结构,具有非常大的孔体积,其值高达单位晶胞体积的72.8%.去除溶剂分子后的1a表现出永久孔性,其Langmuir表面积为2844 m2·g-1,BET表面积为1 852 m2·g-1.它对H2、CO2、CH4和C2H2具有可

  7. Light-emitting conjugated polymers with microporous network architecture: interweaving scaffold promotes electronic conjugation, facilitates exciton migration, and improves luminescence.

    Science.gov (United States)

    Xu, Yanhong; Chen, Long; Guo, Zhaoqi; Nagai, Atsushi; Jiang, Donglin

    2011-11-09

    Herein we report a strategy for the design of highly luminescent conjugated polymers by restricting rotation of the polymer building blocks through a microporous network architecture. We demonstrate this concept using tetraphenylethene (TPE) as a building block to construct a light-emitting conjugated microporous polymer. The interlocked network successfully restricted the rotation of the phenyl units, which are the major cause of fluorescence deactivation in TPE, thus providing intrinsic luminescence activity for the polymers. We show positive "CMP effects" that the network promotes π-conjugation, facilitates exciton migration, and improves luminescence activity. Although the monomer and linear polymer analogue in solvents are nonemissive, the network polymers are highly luminescent in various solvents and the solid state. Because emission losses due to rotation are ubiquitous among small chromophores, this strategy can be generalized for the de novo design of light-emitting materials by integrating the chromophores into an interlocked network architecture.

  8. Ozone treatment of coal- and coffee grounds-based active carbons: Water vapor adsorption and surface fractal micropores

    Energy Technology Data Exchange (ETDEWEB)

    Tsunoda, Ryoichi; Ozawa, Takayoshi; Ando, Junichi [Kanagawa Industrial Technology Research Inst., Ebina, Kanagawa (Japan)

    1998-09-15

    Characteristics of the adsorption iostherms of water vapor on active carbons from coal and coffee grounds and those ozonized ones from the surface fractal dimension analysis are discussed. The upswing of the adsorption isotherms in the low relative pressure of coffee grounds-based active carbon, of which isotherms were not scarcely affected on ozonization, was attributed to the adsorption of water molecules on the metallic oxides playing the role of oxygen-surface complexes, which formed the corrugated surfaces on the basal planes of micropore walls with the surface fractal dimension D{sub s} > 2. On the other hand, coal-based active carbon with D{sub s} < 2, which indicated the flat surfaces of micropore walls, showed little effect on the upswing even on ozonization, even though the adsorption amounts of water vapor were increased in the low relative pressure.

  9. Extension of the Dubinin-Astakhov equation for evaluating the micropore size distribution of a modified carbon molecular sieve.

    Science.gov (United States)

    Gil, A; Korili, S A; Cherkashinin, G Yu

    2003-06-15

    A new method for the characterization of the pore size distribution of microporous solids is applied on data obtained for activated carbon molecular sieve samples. In this method, based on the Dubinin-Astakhov equation, a simple numerical algorithm is used for the reconstruction of the micropore size distribution from the integral equation that represents the experimental nitrogen adsorption isotherm. The results are compared with the ones obtained on the basis of the well-known Horvath-Kawazoe method. The samples used in this study come from a carbon molecular sieve that has been treated with solutions of concentrated HNO3 at various temperatures and with solutions of H2O2 of various concentrations.

  10. Xe Adsorption and Separation Properties of a Series of Microporous Metal–Organic Frameworks (MOFs) with V-Shaped Linkers

    Energy Technology Data Exchange (ETDEWEB)

    Banerjee, Debasis; Elsaidi, Sameh K.; Thallapally, Praveen K.

    2017-08-28

    A series of microporous Metal-Organic Frameworks (MOFs) constructed by a V-shaped linker, 4,4’-sul-fonyldibenzoic acid were evaluated for their Xe gas adsorption properties. In particular, a cadmium based MOF exhibit noteworthy Xe adsorption and separation properties in presence of other gases under nuclear reprocessing conditions. The difference in Xe adsorption and separation properties of the materials were attributed towards their topology and pore size.

  11. Microporous metal–organic framework with dual functionalities for highly efficient removal of acetylene from ethylene/acetylene mixtures

    OpenAIRE

    Hu, T.L.; Wang, H.; Li, B.; R. Krishna; Wu, H; Zhou, W.; Zhao, Y.; Han, Y.; Wang, X.; Zhu, W.; Yao, Z; Xiang, S.; Chen, B

    2015-01-01

    The removal of acetylene from ethylene/acetylene mixtures containing 1% acetylene is a technologically very important, but highly challenging task. Current removal approaches include the partial hydrogenation over a noble metal catalyst and the solvent extraction of cracked olefins, both of which are cost and energy consumptive. Here we report a microporous metal–organic framework in which the suitable pore/cage spaces preferentially take up much more acetylene than ethylene while the functio...

  12. Ordered hierarchical mesoporous/microporous carbon derived from mesoporous titanium-carbide/carbon composites and its electrochemical performance in supercapacitor

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Hai-Jing; Wang, Jie; Wang, Cong-Xiao; Xia, Yong-Yao [Department of Chemistry and Shanghai Key Laboratory of Molecular, Catalysis and Innovative Materials, Institute of New Energy, Fudan University, Shanghai (China)

    2011-11-15

    Novel ordered hierarchical mesoporous/microporous carbon (OHMMC) derived from mesoporous titanium-carbide/carbon composites was prepared for the first time by synthesizing ordered mesoporous nanocrystalline titanium-carbide/carbon composites, followed by chlorination of titanium carbides. The mesostructure and microstructure can be conveniently tuned by controlling the TiC contents of mesoporous TiC/C composite precursor, and chlorination temperature. By optimal condition, the OHMMC has a high surface area (1917 m{sup 2}g{sup -1}), large pore volumes (1.24 cm{sup 3}g{sup -1}), narrow mesopore-size distributions (centered at about 3 nm), and micropore size of 0.69 and 1.25 nm, and shows a great potential as electrode for supercapacitor applications: it exhibits a high capacitance of 146 Fg{sup -1} in noaqueous electrolyte and excellent rate capability. The ordered mesoporous channel pores are favorable for retention and immersion of the electrolyte, providing a more favorable path for electrolyte penetration and transportation to achieve promising rate capability performance. Meanwhile, the micropores drilled on the mesopore-walls can increase the specific surface area to provide more sites for charge storage. (Copyright copyright 2011 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  13. Highly microporous carbons derived from a complex of glutamic acid and zinc chloride for use in supercapacitors

    Science.gov (United States)

    Dong, Xiao-Ling; Lu, An-Hui; He, Bin; Li, Wen-Cui

    2016-09-01

    The selection of carbon precursor is an important factor when designing carbon materials. In this study, a complex derived from L-glutamic acid and zinc chloride was used to prepare highly microporous carbons via facile pyrolysis. L-glutamic acid, a new carbon precursor with nitrogen functionality, coordinated with zinc chloride resulted in a homogeneous distribution of Zn2+ on the molecular level. During pyrolysis, the evaporation of the in situ formed zinc species creates an abundance of micropores together with the inert gases. The obtained carbons exhibit high specific surface area (SBET: 1203 m2 g-1) and a rich nitrogen content (4.52 wt%). In excess of 89% of the pore volume consists of micropores with pore size ranging from 0.5 to 1.2 nm. These carbons have been shown to be suitable for use as supercapacitor electrodes, and have been tested in 6 M KOH where a capacitance of 217 F g-1 was achieved at a current density of 0.5 A g-1. A long cycling life of 30 000 cycles was achieved at a current density of 1 A g-1, with only a 9% loss in capacity. The leakage current through a two-electrode device was measured as 2.3 μA per mg of electrode and the self-discharge characteristics were minimal.

  14. Investigation into the Catalytic Activity of Microporous and Mesoporous Catalysts in the Pyrolysis of Waste Polyethylene and Polypropylene Mixture

    Directory of Open Access Journals (Sweden)

    Kaixin Li

    2016-06-01

    Full Text Available Catalytic pyrolysis behavior of synthesized microporous catalysts (conventional Zeolite Socony Mobil–5 (C-ZSM-5, highly uniform nanocrystalline ZSM-5 (HUN-ZSM-5 and β-zeolite, Mesoporous catalysts (highly hydrothermally stable Al-MCM-41 with accessible void defects (Al-MCM-41(hhs, Kanemite-derived folded silica (KFS-16B and well-ordered Al-SBA-15 (Al-SBA-15(wo were studied with waste polyethylene (PE and polypropylene (PP mixture which are the main constituents in municipal solid waste. All the catalysts were characterized by Brunauer-Emmett-Teller (BET, X-ray powder diffraction (XRD, and NH3-temperature programmed desorption (TPD. The results demonstrated that microporous catalysts exhibited high yields of gas products and high selectivity for aromatics and alkene, whereas the mesoporous catalysts showed high yields of liquid products with considerable amounts of aliphatic compounds. The differences between the microporous and mesoporous catalysts could be attributed to their characteristic acidic and textural properties. A significant amount of C2–C4 gases were produced from both types of catalysts. The composition of the liquid and gas products from catalytic pyrolysis is similar to petroleum-derived fuels. In other words, products of catalytic pyrolysis of plastic waste can be potential alternatives to the petroleum-derived fuels.

  15. Degradation of N-nitrosodimethylamine (NDMA) and its precursor dimethylamine (DMA) in mineral micropores induced by microwave irradiation.

    Science.gov (United States)

    He, Yuanzhen; Cheng, Hefa

    2016-05-01

    Removal of N-nitrosodimethylamine (NDMA) in drinking water treatment poses a significant technical challenge due to its small molecular size, high polarity and water solubility, and poor biodegradability. Degradation of NDMA and its precursor, dimethylamine (DMA), was investigated by adsorbing them from aqueous solution using porous mineral sorbents, followed by destruction under microwave irradiation. Among the mineral sorbents evaluated, dealuminated ZSM-5 exhibited the highest sorption capacities for NDMA and DMA, which decreased with the density of surface cations present in the micropores. In contrast, the degradation rate of the sorbed NDMA increased with the density of surface cations under microwave irradiation. Evolutions of the degradation products and C/N ratio indicate that the sorbed NDMA and DMA could be eventually mineralized under continuous microwave irradiation. The degradation rate was strongly correlated with the bulk temperature of ZSM-5 and microwave power, which is consistent with the mechanism of pyrolysis caused by formation of micro-scale "hot spots" within the mineral micropores under microwave irradiation. Compared to existing treatment options for NDMA removal, microporous mineral sorption coupled with microwave-induced degradation has the unique advantages of being able to simultaneously remove NDMA and DMA and cause their full mineralization, and thus could serve as a promising alternative method. Copyright © 2016 Elsevier Ltd. All rights reserved.

  16. Ozonation of azo dye Acid Red 14 in a microporous tube-in-tube microchannel reactor: decolorization and mechanism.

    Science.gov (United States)

    Gao, Meiping; Zeng, Zequan; Sun, Baochang; Zou, Haikui; Chen, Jianfeng; Shao, Lei

    2012-09-01

    The ozonation of synthetic wastewater containing azo dye Acid Red 14 (AR 14) was investigated in a high-throughput microporous tube-in-tube microchannel reactor. The effects of design and operating parameters such as micropore size, annular channel width, liquid volumetric flow rate, ozone-containing gas volumetric flow rate, initial pH of the solution and initial AR 14 concentration on decolorization efficiency and ozone utilization efficiency were studied with the aim to optimize the operation conditions. An increase of the ozone-containing gas or liquid flow rate could greatly intensify the gas-liquid mass transfer. Reducing the micropore size and the annular channel width led to a higher mass transfer rate and was beneficial to decolorization. Decolorization efficiency increased with an increasing ozone-containing gas volumetric flow rate, as well as a decreasing liquid volumetric flow rate and initial AR 14 concentration. The optimum initial pH for AR 14 ozonation was determined as 9.0. The degradation kinetics was observed to be a pseudo-first-order reaction with respect to AR 14 concentration. The difference between the decolorization and COD removal efficiency indicated that many intermediates existed in AR 14 ozonation. The formation of six organic intermediates during ozonation was detected by GC/MS, while the concentration of nitrate and sulfate ions was determined by ion chromatography. The possible degradation mechanism of AR 14 in aqueous solution was proposed.

  17. A novel composite microporous polymer electrolyte prepared with molecule sieves for Li-ion batteries

    Science.gov (United States)

    Jiang, Yan-Xia; Chen, Zuo-Feng; Zhuang, Quan-Chao; Xu, Jin-Mei; Dong, Quan-Feng; Huang, Ling; Sun, Shi-Gang

    Molecular sieves of NaY, MCM-41, and SBA-15 were used as fillers in a poly(vinylidene fluoride- co-hexafluoropropylene) (PVdF-HFP) copolymer matrix to prepare microporous composite polymer electrolyte. The SBA-15-based composite polymer film was found to show rich pores that account for an ionic conductivity of 0.50 mS cm -1. However, the MCM-41 and NaY composite polymer films exhibited compact structure without any pores, and the addition of MCM-41 even resulted in aggregation of fillers in the polymer matrix. These differences were investigated and interpreted by their different compatibility with DMF solvent and PVdF-HFP matrix. Results of linear sweep voltammetry (LSV), electrochemical impedance spectroscopy (EIS), X-ray diffraction (XRD) and differential scanning calorimetry (DSC) have revealed that the addition of SBA-15 has extended the electrochemical stability window of polymer electrolyte, enhanced the interfacial stability of polymer electrolyte with lithium electrode, and inhibited also the crystallization of PVdF-HFP matrix. Half-cell of Li/SBA-15-based polymer electrolyte/MCF was assembled and tested. The results have demonstrated that the coulombic efficiency of the first cycle was around 87.0% and the cell remains 94.0% of the initial capacity after 20 cycles, which showed the potential application of the composite polymer electrolyte in lithium ion batteries.

  18. A novel composite microporous polymer electrolyte prepared with molecule sieves for Li-ion batteries

    Energy Technology Data Exchange (ETDEWEB)

    Jiang, Yan-Xia; Chen, Zuo-Feng; Zhuang, Quan-Chao; Xu, Jin-Mei; Dong, Quan-Feng; Huang, Ling; Sun, Shi-Gang [State Key Laboratory of Physical Chemistry of Solid Surfaces, Department of Chemistry, College of Chemistry and Chemical Engineering, Xiamen University, 422, South Road of Siming, Xiamen 361005 (China)

    2006-10-06

    Molecular sieves of NaY, MCM-41, and SBA-15 were used as fillers in a poly(vinylidene fluoride-co-hexafluoropropylene) (PVdF-HFP) copolymer matrix to prepare microporous composite polymer electrolyte. The SBA-15-based composite polymer film was found to show rich pores that account for an ionic conductivity of 0.50mScm{sup -1}. However, the MCM-41 and NaY composite polymer films exhibited compact structure without any pores, and the addition of MCM-41 even resulted in aggregation of fillers in the polymer matrix. These differences were investigated and interpreted by their different compatibility with DMF solvent and PVdF-HFP matrix. Results of linear sweep voltammetry (LSV), electrochemical impedance spectroscopy (EIS), X-ray diffraction (XRD) and differential scanning calorimetry (DSC) have revealed that the addition of SBA-15 has extended the electrochemical stability window of polymer electrolyte, enhanced the interfacial stability of polymer electrolyte with lithium electrode, and inhibited also the crystallization of PVdF-HFP matrix. Half-cell of Li/SBA-15-based polymer electrolyte/MCF was assembled and tested. The results have demonstrated that the coulombic efficiency of the first cycle was around 87.0% and the cell remains 94.0% of the initial capacity after 20 cycles, which showed the potential application of the composite polymer electrolyte in lithium ion batteries. (author)

  19. A microporous silk carbon-ionic liquid composite for the electrochemical sensing of dopamine.

    Science.gov (United States)

    Wang, Min; Bai, Lu; Zhang, Lingling; Sun, Guangping; Zhang, Xiaowei; Dong, Shaojun

    2016-04-21

    Porous silk carbon (Silk C) was obtained through carbonization and KOH activation of natural silk cocoons. The as-prepared Silk C presented the good characteristics of a large surface area (SBET: 2854.53 m(2) g(-1)) and a high volume of pores (1.54 cm(3) g(-1)) with uniform micropores (2.5 nm) and multiple defects. The metal-free silk carbon-ionic liquid (Silk C-IL) composite, synthesized by modifying Silk C with ionic liquid through non-covalent (π-π) interactions under grinding conditions, was prepared for electrochemical determination of dopamine (DA). The detection limit of DA was 79 nM (S/N = 3) with a linear range from 0.6 μM to 140 μM. Meanwhile, the as-made Silk C-IL/GCE presented good selectivity for DA detection from other possible interferences, such as ascorbic acid, glucose and uric acid. Furthermore, the Silk C-IL/GCE was also successfully used for the detection of DA in fetal bovine serum and dopamine hydrochloride injection samples.

  20. Ab initio density-functional calculations in materials science: from quasicrystals over microporous catalysts to spintronics.

    Science.gov (United States)

    Hafner, Jürgen

    2010-09-29

    During the last 20 years computer simulations based on a quantum-mechanical description of the interactions between electrons and atomic nuclei have developed an increasingly important impact on materials science, not only in promoting a deeper understanding of the fundamental physical phenomena, but also enabling the computer-assisted design of materials for future technologies. The backbone of atomic-scale computational materials science is density-functional theory (DFT) which allows us to cast the intractable complexity of electron-electron interactions into the form of an effective single-particle equation determined by the exchange-correlation functional. Progress in DFT-based calculations of the properties of materials and of simulations of processes in materials depends on: (1) the development of improved exchange-correlation functionals and advanced post-DFT methods and their implementation in highly efficient computer codes, (2) the development of methods allowing us to bridge the gaps in the temperature, pressure, time and length scales between the ab initio calculations and real-world experiments and (3) the extension of the functionality of these codes, permitting us to treat additional properties and new processes. In this paper we discuss the current status of techniques for performing quantum-based simulations on materials and present some illustrative examples of applications to complex quasiperiodic alloys, cluster-support interactions in microporous acid catalysts and magnetic nanostructures.

  1. Modelling metal centres, acid sites and reaction mechanisms in microporous catalysts.

    Science.gov (United States)

    O'Malley, Alexander J; Logsdail, A J; Sokol, A A; Catlow, C R A

    2016-07-04

    We discuss the role of QM/MM (embedded cluster) computational techniques in catalytic science, in particular their application to microporous catalysis. We describe the methodologies employed and illustrate their utility by briefly summarising work on metal centres in zeolites. We then report a detailed investigation into the behaviour of methanol at acidic sites in zeolites H-ZSM-5 and H-Y in the context of the methanol-to-hydrocarbons/olefins process. Studying key initial steps of the reaction (the adsorption and subsequent methoxylation), we probe the effect of framework topology and Brønsted acid site location on the energetics of these initial processes. We find that although methoxylation is endothermic with respect to the adsorbed system (by 17-56 kJ mol(-1) depending on the location), there are intriguing correlations between the adsorption/reaction energies and the geometries of the adsorbed species, of particular significance being the coordination of methyl hydrogens. These observations emphasise the importance of adsorbate coordination with the framework in zeolite catalysed conversions, and how this may vary with framework topology and site location, particularly suited to investigation by QM/MM techniques.

  2. Preparing two-dimensional microporous carbon from Pistachio nutshell with high areal capacitance as supercapacitor materials

    Science.gov (United States)

    Xu, Jiandong; Gao, Qiuming; Zhang, Yunlu; Tan, Yanli; Tian, Weiqian; Zhu, Lihua; Jiang, Lei

    2014-07-01

    Two-dimensional (2D) porous carbon AC-SPN-3 possessing of amazing high micropore volume ratio of 83% and large surface area of about 1069 m2 g-1 is high-yield obtained by pyrolysis of natural waste Pistachio nutshells with KOH activation. The AC-SPN-3 has a curved 2D lamellar morphology with the thickness of each slice about 200 nm. The porous carbon is consists of highly interconnected uniform pores with the median pore diameter of about 0.76 nm, which could potentially improve the performance by maximizing the electrode surface area accessible to the typical electrolyte ions (such as TEA+, diameter = ~0.68 nm). Electrochemical analyses show that AC-SPN-3 has significantly large areal capacitance of 29.3/20.1 μF cm-2 and high energy density of 10/39 Wh kg-1 at power of 52/286 kW kg-1 in 6 M KOH aqueous electrolyte and 1 M TEABF4 in EC-DEC (1:1) organic electrolyte system, respectively.

  3. An electrochemical and high-speed imaging study of micropore decontamination by acoustic bubble entrapment.

    Science.gov (United States)

    Offin, Douglas G; Birkin, Peter R; Leighton, Timothy G

    2014-03-14

    Electrochemical and high-speed imaging techniques are used to study the abilities of ultrasonically-activated bubbles to clean out micropores. Cylindrical pores with dimensions (diameter × depth) of 500 μm × 400 μm (aspect ratio 0.8), 125 μm × 350 μm (aspect ratio 2.8) and 50 μm × 200 μm (aspect ratio 4.0) are fabricated in glass substrates. Each pore is contaminated by filling it with an electrochemically inactive blocking organic material (thickened methyl salicylate) before the substrate is placed in a solution containing an electroactive species (Fe(CN)6(3-)). An electrode is fabricated at the base of each pore and the Faradaic current is used to monitor the decontamination as a function of time. For the largest pore, decontamination driven by ultrasound (generated by a horn type transducer) and bulk fluid flow are compared. It is shown that ultrasound is much more effective than flow alone, and that bulk fluid flow at the rates used cannot decontaminate the pore completely, but that ultrasound can. In the case of the 125 μm pore, high-speed imaging is used to elucidate the cleaning mechanisms involved in ultrasonic decontamination and reveals that acoustic bubble entrapment is a key feature. The smallest pore is used to explore the limits of decontamination and it is found that ultrasound is still effective at this size under the conditions employed.

  4. Intrinsically Microporous Polymer Retains Porosity in Vacuum Thermolysis to Electroactive Heterocarbon.

    Science.gov (United States)

    Rong, Yuanyang; He, Daping; Sanchez-Fernandez, Adrian; Evans, Craig; Edler, Karen J; Malpass-Evans, Richard; Carta, Mariolino; McKeown, Neil B; Clarke, Tomos J; Taylor, Stuart H; Wain, Andrew J; Mitchels, John M; Marken, Frank

    2015-11-10

    Vacuum carbonization of organic precursors usually causes considerable structural damage and collapse of morphological features. However, for a polymer with intrinsic microporosity (PIM-EA-TB with a Brunauer-Emmet-Teller (BET) surface area of 1027 m(2)g(-1)), it is shown here that the rigidity of the molecular backbone is retained even during 500 °C vacuum carbonization, yielding a novel type of microporous heterocarbon (either as powder or as thin film membrane) with properties between those of a conducting polymer and those of a carbon. After carbonization, the scanning electron microscopy (SEM) morphology and the small-angle X-ray scattering (SAXS) Guinier radius remain largely unchanged as does the cumulative pore volume. However, the BET surface area is decreased to 242 m(2)g(-1), but microporosity is considerably increased. The new material is shown to exhibit noticeable electrochemical features including two pH-dependent capacitance domains switching from ca. 33 Fg(-1) (when oxidized) to ca. 147 Fg(-1) (when reduced), a low electron transfer reactivity toward oxygen and hydrogen peroxide, and a four-point-probe resistivity (dry) of approximately 40 MΩ/square for a 1-2 μm thick film.

  5. Bifunctionalized Intrinsically Microporous Polyimides with Simultaneously Enhanced Gas Permeability and Selectivity.

    Science.gov (United States)

    Ma, Xiaohua; Mukaddam, Mohsin; Pinnau, Ingo

    2016-06-01

    Two novel intrinsically microporous copolyimides synthesized by condensation reaction of 4,4'-(hexafluoroisopropylidene) diphthalic anhydride (6FDA), 3,3,3',3'-tetramethyl-1,1'-spirobisindane-5,5'-diamino-6,6'-diol, and 3,5-diaminobenzoic acid with diamine ratios of 80/20 (Co-80/20) and 50/50 (Co-50/50) are reported. Unexpectedly, the Co-80/20 not only demonstrates higher microporosity (300 m(2) g(-1) ) than the PIM-6FDA-OH homopolymer (190 m(2) g(-1) ) but also exhibits simultaneously enhanced CO2 permeability (from 119 to 171 Barrer) and CO2 /CH4 selectivity (from 35 to 41) after thermal annealing at 250 °C. This higher permeability originates from enhanced diffusivity (D CO2 ) and the higher selectivity results from its increased diffusion selectivity (D CO2 /D CH4 ). After crosslinking at 300 °C, the Co-80/20 exhibits an even higher CO2 permeability (261 Barrer) and almost unchanged CO2 /CH4 selectivity.

  6. Extraordinary Capability for Water Treatment Achieved by a Perfluorous Conjugated Microporous Polymer

    Science.gov (United States)

    Yang, Rui-Xia; Wang, Ting-Ting; Deng, Wei-Qiao

    2015-05-01

    Oils, organic solvents, dyes, and heavy metal ions are primary pollutants in water resources. Currently, no sorbent material can effectively remove these types of pollutants simultaneously. Here we report a perfluorous conjugated microporous polymer with superhydrophobicity and a large surface area, which exhibits outstanding adsorption capacities, kinetics, and recyclability for a wide range of organic solvents, oils, dyes, and heavy metal ions. The adsorption capacities of this polymer, 1376.7 mg g-1 for Congo red, 808.2 mg g-1 for Pb(II) and 303.2 mg g-1 for As(V), are higher than the adsorption capacities of any previously described porous materials. Our theoretical calculation reveals that the superior properties of this polymer are due to fluorination and triple bonds within the polymer. A benchmark experiment indicates that this polymer can efficiently remove these pollutants simultaneously. Application of this polymer may lead to the development of next-generation reusable and portable water purification appliances.

  7. Release Kinetics and Antibacterial Efficacy of Microporous β-TCP Coatings

    Directory of Open Access Journals (Sweden)

    Michael Seidenstuecker

    2013-01-01

    Full Text Available Purpose. The aim of this study was to impregnate microporous β-TCP scaffolds with different antibiotic solutions and to determine their release behavior. Materials and Methods. We impregnated a β-TCP scaffold with antibiotics by using three methods: drop, dip, and stream coating with 120 mg/mL of antibiotic solution. After drying for 72 h at 37°C, 2 mL of distilled water was added to the antibiotic-coated plugs and incubated at 37°C. After defined time points (1, 2, 3, 6, 9, and 14 days, the liquid was completely replaced. The extracted liquid was analyzed by capillary zone electrophoresis and the Kirby Bauer disc diffusion test. For statistical analysis, we calculated a mean and standard deviation and carried out an analysis of variance using ANOVA. Results. The VAN and CLI release from the β-TCP scaffolds was rapid, occurring within 24 h with 89 ± 0.8% VAN and 90.4 ± 1.5% CLI regardless of the type of insulation. After six days, the VAN and CLI were completely released. All samples taken at later time points had a VAN or CLI concentration below the detection limit of 4 µg/mL. The released amounts of VAN and CLI within the first three days revealed antimicrobial activity.

  8. Hybrid Mesoporous Silicas and Microporous POSS-Based Frameworks Incorporating Evaporation-Induced Self-Assembly

    Directory of Open Access Journals (Sweden)

    Jheng-Guang Li

    2015-06-01

    Full Text Available We fabricated a series of mesoporous silicas and mesoporous organosilicates with hierarchical porosity through evaporation-induced self-assembly using Pluronic F127 as a template in this study. We could tailor the mesophase of each mesoporous silica sample by varying the weight ratio of its two silica sources: tetraethyl orthosilicate (TEOS and triethoxysilane hydrosilylated octavinyl polyhedral oligomeric silsesquioxane (OV-POSS-SILY. The mesophases ranged from an ordered body-centered cubic (bcc structure (TEOS alone to ordered face-centered cubic (fcc structure (10 and 20 wt.% of OV-POSS-SILY and finally to disordered spherical pores (≥30 wt.% of OV-POSS-SILY. We used small-angle X-ray scattering (SAXS and transmission electron microscopy (TEM to study the transformations of these mesophases, while N2 isotherm sorption curves revealed the porosities of these mesoporous silicate samples. Moreover, 29Si CP/MAS solid state nuclear magnetic resonance spectroscopy allowed us to analyze the compositions of the POSS-containing silicate frameworks. Such functional mesoporous silica samples incorporating microporous POSS building units have potential applications in various systems, including optical and electronic devices.

  9. The hydrogen-storing microporous silica 'Microcluster' reduces acetaldehyde contained in a distilled spirit.

    Science.gov (United States)

    Kato, Shinya; Miwa, Nobuhiko

    2016-12-01

    Acetaldehyde is a detrimental substance produced in alcoholic liquor aging. We assessed an ability of hydrogen-storing microporous silica 'Microcluster' (MC+) to reduce acetaldehyde, as compared with autoclave-dehydrogenated MC+ (MC-). Acetaldehyde was quantified spectrophotometrically by an enzymatic method. Authentic acetaldehyde was treated by MC+ for 20min, and decreased from 43.4ppm to 10.9ppm, but maintained at 49.3ppm by MC-. On the other hand, acetaldehyde contained in a distilled spirit was decreased from 29.5ppm to 3.1ppm at 20min by MC+, but not decreased by MC-. Addition of MC+ or MC- to distilled water without acetaldehyde showed no seeming effect on the quantification used. Accordingly acetaldehyde in a distilled spirit is reduced to ethanol by hydrogen contained in MC+, but not by the silica moiety of MC+. Hydrogen gas of 1.2mL was released for 20min from MC+ of 0.59g in water, resulting in dissolved hydrogen of 1.09ppm and an oxidation- reduction potential of -687.0mV indicative of a marked reducing ability. Thus, MC+ has an ability to reduce acetaldehyde in a distilled spirit due to dissolved hydrogen released from MC+. Copyright © 2016 Elsevier B.V. All rights reserved.

  10. Carbon molecular sieve gas separation membranes based on an intrinsically microporous polyimide precursor

    KAUST Repository

    Ma, Xiaohua

    2013-10-01

    We report the physical characteristics and gas transport properties for a series of pyrolyzed membranes derived from an intrinsically microporous polyimide containing spiro-centers (PIM-6FDA-OH) by step-wise heat treatment to 440, 530, 600, 630 and 800 C, respectively. At 440 C, the PIM-6FDA-OH was converted to a polybenzoxazole and exhibited a 3-fold increase in CO2 permeability (from 251 to 683 Barrer) with a 50% reduction in selectivity over CH4 (from 28 to 14). At 530 C, a distinct intermediate amorphous carbon structure with superior gas separation properties was formed. A 56% increase in CO2-probed surface area accompanied a 16-fold increase in CO2 permeability (4110 Barrer) over the pristine polymer. The graphitic carbon membrane, obtained by heat treatment at 600 C, exhibited excellent gas separation properties, including a remarkable CO2 permeability of 5040 Barrer with a high selectivity over CH4 of 38. Above 600 C, the strong emergence of ultramicroporosity (<7 Å) as evidenced by WAXD and CO2 adsorption studies elicits a prominent molecular sieving effect, yielding gas separation performance well above the permeability-selectivity trade-off curves of polymeric membranes. © 2013 Elsevier Ltd. All rights reserved.

  11. Spontaneous cracking of amorphous solid water films and the dependence on microporous structure

    Science.gov (United States)

    Bu, Caixia; Dukes, Catherine A.; Baragiola, Raúl A.

    2016-11-01

    Vapor-deposited, porous, amorphous, water-ice films, also called amorphous solid water (ASW), crack spontaneously during growth when the film thickness exceeds a critical value (Lc). We measured the Lc during growth of ASW films as a function of growth temperature (Tg = 10 K, 30 K, and 50 K) and deposition angle (θ = 0°, 45°, and 55°) using a quartz crystal microbalance, an optical interferometer, and an infrared spectrometer. The critical thickness, 1-5 μm under our experimental conditions, increases with Tg and θ, an indication of film porosity. We suggest that ASW films undergo tensile stress due to the mismatch between substrate adhesion and contracting forces derived from the incompletely coordinated molecules on the surfaces of the pores. We provide a model to explain the observed dependences of Lc on the Tg and θ in the context of Griffith theory and estimate the tensile strength of low-temperature ASW to be ˜25-40 MPa. Our model can be applied more generally to describe fracture of other solids with microporous structures, such as metallic or ceramic materials with voids.

  12. Thermomechanical analysis and durability of commercial micro-porous polymer Li-ion battery separators

    Science.gov (United States)

    Love, Corey T.

    2011-03-01

    Static and dynamic thermomechanical analysis was performed with a dynamic mechanical analyzer (DMA) to identify thermal and mechanical transitions for commercially available polymer separators under mechanical loading. Clear transitions in deformation mode were observed at elevated temperatures. These transitions identified the onset of separator "shutdown" which occurred at temperatures below the polymer melting point. Mechanical loading direction was critical to the overall integrity of the separator. Anisotropic separators (Celgard 2320, 2400 and 2500) were mechanically limited when pulled in tensile in the transverse direction. The anisotropy of these separators is a result of the dry technique used to manufacture the micro-porous membranes. Separators prepared using the wet technique (Entek Gold LP) behaved more uniformly, or biaxially, where all mechanical properties were nearly identical within the separator plane. The information provided by the DMA can also be useful for predicting the long-term durability of polymer separators in lithium-ion batteries exposed to electrolyte (solvent and salt), thermal fluctuations and electrochemical cycling. Small losses in mechanical integrity were observed for separators exposed to the various immersion environments over the 4-week immersion time.

  13. Enhanced Salt Removal in an Inverted Capacitive Deionization Cell Using Amine Modified Microporous Carbon Cathodes.

    Science.gov (United States)

    Gao, Xin; Omosebi, Ayokunle; Landon, James; Liu, Kunlei

    2015-09-15

    Microporous SpectraCarb carbon cloth was treated using nitric acid to enhance negative surface charges of COO(-) in a neutral solution. This acid-treated carbon was further modified by ethylenediamine to attach -NH2 surface functional groups, resulting in positive surface charges of -NH3(+) via pronation in a neutral solution. Through multiple characterizations, in comparison to pristine SpectraCarb carbon, amine-treated SpectraCarb carbon displays a decreased potential of zero charge but an increased point of zero charge, which is opposed to the effect obtained for acid-treated SpectraCarb carbon. An inverted capacitive deionization cell was constructed using amine-treated cathodes and acid-treated anodes, where the cathode is the negatively polarized electrode and the anode is the positively polarized electrode. Constant-voltage switching operation using NaCl solution showed that the salt removal capacity was approximately 5.3 mg g(-1) at a maximum working voltage of 1.1/0 V, which is an expansion in both the salt capacity and potential window from previous i-CDI results demonstrated for carbon xerogel materials. This improved performance is accounted for by the enlarged cathodic working voltage window through ethylenediamine-derived functional groups, and the enhanced microporosity of the SpectraCarb electrodes for salt adsorption. These results expand the use of i-CDI for efficient desalination applications.

  14. Vanadium nitride quantum dot/nitrogen-doped microporous carbon nanofibers electrode for high-performance supercapacitors

    Science.gov (United States)

    Wu, Yage; Ran, Fen

    2017-03-01

    In this article, vanadium nitride quantum dot/nitrogen-doped microporous carbon nanofibers (VNQD/CNF) is developed by a method of combination of electrostatic spinning and high-temperature calcination under the atmosphere of NH3: N2 = 3: 2 for high performance supercapacitors. VNQD dispersing into CNF, enrichment of N atom doped in carbon bulk, and abundant porous structure not only prevent the growth and aggregation of VN nanoparticles, improve electrical conductivity, wettability, and stability of the electrode materials, but also enhance fast migration of electrolyte ions during the electrochemical process. Thus, VNQD/CNF exhibits a high specific capacitance of 406.5 F g-1 at 0.5 A g-1 and a good rate capability with a capacitance retention of 75.1% at 5.0 A g-1. Additionally, VNQD/CNF as a negative electrode are combined with Ni(OH)2 as a positive electrode to fabricate the hybrid supercapacitor of VNQD/CNF//Ni(OH)2. Remarkably, at a power density of 774.6 W kg-1, the supercapacitor device delivers an ultrahigh energy density of 31.2 Wh kg-1.

  15. Analysis of ammonia separation from purge gases in microporous hollow fiber membrane contactors.

    Science.gov (United States)

    Karami, M R; Keshavarz, P; Khorram, M; Mehdipour, M

    2013-09-15

    In this study, a mathematical model was developed to analyze the separation of ammonia from the purge gas of ammonia plants using microporous hollow fiber membrane contactors. A numerical procedure was proposed to solve the simultaneous linear and non linear partial differential equations in the liquid, membrane and gas phases for non-wetted or partially wetted conditions. An equation of state was applied in the model instead of Henry's law because of high solubility of ammonia in water. The experimental data of CO₂-water system in the literature was used to validate the model due to the lack of data for ammonia-water system. The model showed that the membrane contactor can separate ammonia very effectively and with recoveries higher than 99%. SEM images demonstrated that ammonia caused some micro-cracks on the surfaces of polypropylene fibers, which could be an indication of partial wetting of membrane in long term applications. However, the model results revealed that the membrane wetting did not have significant effect on the absorption of ammonia because of very high solubility of ammonia in water. It was also found that the effect of gas velocity on the absorption flux was much more than the effect of liquid velocity.

  16. Natural gas storage in microporous carbon obtained from waste of the olive oil production

    Directory of Open Access Journals (Sweden)

    Cecilia Solar

    2008-12-01

    Full Text Available A series of activated carbons (AC were prepared from waste of the olive oil production in the Cuyo Region, Argentine by two standard methods: a physical activation by steam and b chemical activation with ZnCl2. The AC samples were characterized by nitrogen adsorption at 77 K and evaluated for natural gas storage purposes through the adsorption of methane at high pressures. The activated carbons showed micropore volumes up to 0.50 cm³.g-1 and total pore volumes as high as 0.9 cm³.g-1. The BET surface areas reached, in some cases, more than 1000 m².g-1. The methane adsorption -measured in the range of 1-35 bar- attained values up to 59 V CH4/V AC and total uptakes of more than 120 cm³.g-1 (STP. These preliminary results suggest that Cuyo's olive oil waste is appropriate for obtaining activated carbons for the storage of natural gas.

  17. Preparation and supercapacitive behaviors of the ordered mesoporous/microporous chromium carbide-derived carbons

    Science.gov (United States)

    Wu, Chun; Gao, Jiao; Zhao, Qinglan; Zhang, Youwei; Bai, Yansong; Wang, Xingyan; Wang, Xianyou

    2014-12-01

    A series of ordered mesoporous/microporous carbon materials derived from chromium carbide-derived carbons (CDCs) are prepared by nanocasting the chromic acetate and furfuryl alcohol precursor into SBA-15 and subsequent chlorination. The structure and morphology of the CDCs are characterized by N2 adsorption/desorption isotherm, scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The results show that all of the synthesized CDCs present large specific surface area and pore volume. Especially, the CDCs-2 prepared at the mass ratio of 1/1 (chromic acetate/furfuryl alcohol) exhibits the chain-like morphology with high surface area (1236 m2 g-1), large pore volume (0.76 cm3 g-1), and the good mesopore size centered at 3.43 nm. The electrochemical properties of all the CDCs are studied by cyclic voltammetry, constant current charge/discharge, electrochemical impedance spectroscopy and cycle life measurements in 6 M KOH electrolyte. The results display that the sample CDCs-2 exhibits a high capacitance of 242.7 F g-1 at the current density of 1 A g-1 and good cycling stability with coulombic efficiency of 100% over 10000 cycles.

  18. Surface modifying of microporous PTFE capillary for bilirubin removing from human plasma and its blood compatibility

    Energy Technology Data Exchange (ETDEWEB)

    Jin Gu [Department of Chemistry, University of Science and Technology of China, HeFei, 230026 (China)], E-mail: Gjin@ustc.edu.cn; Yao Qizhi; Zhang Shanzi [Department of Chemistry, University of Science and Technology of China, HeFei, 230026 (China); Zhang Lei [Department of Chemistry, University of Science and Technology of China, HeFei, 230026 (China); AnHui Entry Exit Inspection and Quarantine Bureau, HeFei, 230001 (China)

    2008-12-01

    In this study, human serum albumin (HSA) was covalently immobilized onto the inner surface of microporous poly(tetrafluoroethylene) (MPTFE) capillaries for direct bilirubin removal from human plasma. To obtain active binding sites for HSA, the MPTFE capillaries were chemically functionalized by using a coating of poly(vinyl alcohol) (PVA)-glycidyl methacrylate (GMA) copolymers. Characterization of grafted MPTFE capillaries was verified by XPS, Fourier transform infrared spectroscopy (FT-IR), scanning electronic microscopy (SEM). Non-specific adsorption on the PVA-GMA coated capillary remains low (< 0.38 mg bilirubin/g), and higher affinity adsorption capacity, of up to 73.6 mg bilirubin/g polymer was obtained after HSA is immobilized. Blood compatibility of the grafted MPTFE capillary was evaluated by SEM and platelet rich plasma (PRP) contacting experiments. The experimental data on blood compatibility indicated that PVA-coated and PVA-GMA-HSA coated PTFE capillary showed a sharp suppress on platelets adhesion. The proposed method has the potential of serving in bilirubin removal in clinical application.

  19. Evaluation of a new microporous filtration membrane system for therapeutic plasma exchange.

    Science.gov (United States)

    Kurtz, S R; Carey, P M; McGill, M; Pineda, A A; Zaroulis, C G; Case, M T

    1987-01-01

    A new therapeutic plasma exchange device developed by Sarns Inc./3M was evaluated in plasmapheresis of 20 healthy volunteers and in a multicenter clinical study of therapeutic plasma exchange that included 49 patients. Safety and efficacy of plasma separation from whole blood were assessed for a module that contains Durapore microporous surfactant-free polyvinylidene fluoride membrane (Millipore Corp., Bedford, Mass., USA). The extra-corporeal volume was 80 ml. Citrate and heparin anticoagulants were utilized. Mean plasma separation efficiency was 62% with unhindered passage of plasma proteins through the membrane pores and no hemolysis or activation of complement as measured by total hemolytic complement (CH50) and C3 conversion. Mean decrease in platelet count after procedures was 10%. No severe reactions occurred, and citrate effects (13%) were comparable to values reported with centrifugal instruments. The Sarns Inc./3M Therapore device is a rapid, safe and efficient system for plasma exchange and potentially for source plasma collection. The principal benefits are small extracorporeal volume and cell-free filtrate.

  20. Layered hybrid perovskites with micropores created by alkylammonium functional silsesquioxane interlayers.

    Science.gov (United States)

    Kataoka, Sho; Banerjee, Subhabrata; Kawai, Akiko; Kamimura, Yoshihiro; Choi, Jun-Chul; Kodaira, Tetsuya; Sato, Kazuhiko; Endo, Akira

    2015-04-01

    Layered organic-inorganic hybrid perovskites that consist of metal halides and organic interlayers are a class of low-dimensional materials. Here, we report the fabrication of layered hybrid perovskites using metal halides and silsesquioxane with a cage-like structure. We used a silsesquioxane as an interlayer to produce a rigid structure and improve the functionality of perovskite layers. Propylammonium-functionalized silsesquioxane and metal halide salts (CuCl2, PdCl2, PbCl2, and MnCl2) were self-assembled to form rigid layered perovskite structures with high crystallinity. The rigid silsesquioxane structure produces micropores between the perovskite layers that can potentially be filled with different molecules to tune the dielectric constants of the interlayers. The obtained silsesquioxane-metal halide hybrid perovskites exhibit some characteristic properties of layered perovskites including magnetic ordering (CuCl4(2-) and MnCl4(2-)) and excitonic absorption/emission (PbCl4(2-)). Our results indicate that inserting silsesquioxane interlayers into hybrid perovskites retains and enhances the low-dimensional properties of the materials.

  1. Absorption of Low Concentration Sulfur Dioxide Using Liquid-containing Microporous Membrane

    Institute of Scientific and Technical Information of China (English)

    薛娟琴; 兰新哲; 孟令嫒; 李伟达

    2007-01-01

    The absorption of low concentration SO2 in flue gas by using the module of liquid-containing microporous membrane which iS made up of hollow fiber and citric acid-sodium citrate buffer solution was investigated.The absorption efficiency of hydrophilic and hydrophobic membranes by using the concept of dynamic contact angle was mainly studied.The infuences on absorption efficiency from absorption time,flowrate of gas phase,SO2 concentration of gas phase,air pressure,citrate concentration,pH value of solution as well as the generation of sulfate radical in absorption solution were examined.The results indicate that the hydrophobic hollow fiber membrane is better than hydrophilic membrane,the absorption efficiency decreases with increasing absorption time,gas phase flowrate,gas phase SO2 concentration and air pressure,the absorption rate and capacity of SO2 can be improved by increasing the citrate concentration,the absorption efficiency can be improved by increasing the pH value of citrate solution,the concentration of SO4z- in absorption solution increases linearly with the absorption time at a rate around 0.192g/(L·h).

  2. Correlating N2 and CH4 adsorption on microporous carbon using a new analytical model

    Science.gov (United States)

    Sun, Jielun; Chen, S.; Rood, M.J.; Rostam-Abadi, M.

    1998-01-01

    A new pore size distribution (PSD) model is developed to readily describe PSDs of microporous materials with an analytical expression. Results from this model can be used to calculate the corresponding adsorption isotherm to compare the calculated isotherm to the experimental isotherm. This aspect of the model provides another check on the validity of the model's results. The model is developed on the basis of a 3-D adsorption isotherm equation that is derived from statistical mechanical principles. Least-squares error minimization is used to solve the PSD without any preassumed distribution function. In comparison with several well-accepted analytical methods from the literature, this 3-D model offers a relatively realistic PSD description for select reference materials, including activated-carbon fibers. N2 and CH4 adsorption is correlated using the 3-D model for commercial carbons BPL and AX-21. Predicted CH4 adsorption isotherms at 296 K based on N2 adsorption at 77 K are in reasonable agreement with experimental CH4 isotherms. Use of the model is also described for characterizing PSDs of tire-derived activated carbons and coal-derived activated carbons for air-quality control applications.

  3. Lanthanide metal-organic frameworks as selective microporous materials for adsorption of heavy metal ions.

    Science.gov (United States)

    Jamali, Abbas; Tehrani, Alireza Azhdari; Shemirani, Farzaneh; Morsali, Ali

    2016-06-14

    Four microporous lanthanide metal-organic frameworks (MOFs), namely Ln(BTC)(H2O)(DMF)1.1 (Ln = Tb, Dy, Er and Yb, DMF = dimethylformamide, H3BTC = benzene-1,3,5-tricarboxylic acid), have been used for selective adsorption of Pb(ii) and Cu(ii). Among these MOFs, the Dy-based MOF shows better adsorption property and selectivity toward Pb(ii) and Cu(ii) ions. Adsorption isotherms indicate that sorption of Pb(ii) and Cu(ii) on MOFs is via monolayer coverage. Preconcentration is based on solid-phase extraction in which MOFs were rapidly injected into water samples and adsorption of metal ions was rapid because of good contact with analyte; then adsorbed Pb(ii) and Cu(ii) ions were analyzed by FAAS. The optimized methodology represents good linearity between 1 and 120 μg L(-1) and detection limit of 0.4 and 0.26 μg L(-1) for Pb(ii) and Cu(ii), respectively. Subsequently the method was evaluated for preconcentration of target metal ions in some environmental water samples.

  4. Microporous Organic Polymers Based on Hyper-Crosslinked Coal Tar: Preparation and Application for Gas Adsorption.

    Science.gov (United States)

    Gao, Hui; Ding, Lei; Bai, Hua; Li, Lei

    2017-02-08

    Hyper-crosslinked polymers (HCPs) are promising materials for gas capture and storage, but high cost and complicated preparation limit their practical application. In this paper, a new type of HCPs (CTHPs) was synthesized through a one-step mild Friedel-Crafts reaction with low-cost coal tar as the starting material. Chloroform was utilized as both solvent and crosslinker to generate a three-dimensional crosslinked network with abundant micropores. The maximum BET surface area of the prepared CTHPs could reach up to 929 m(2)  g(-1) . Owing to the high affinity between the heteroatoms on the coal-tar building blocks and the CO2 molecules, the adsorption capacity of CTHPs towards CO2 reached up to 14.2 wt % (1.0 bar, 273 K) with a high selectivity (CO2 /N2 =32.3). Furthermore, the obtained CTHPs could adsorb 1.27 wt % H2 at 1.0 bar and 77.3 K, and also showed capacity for the capture of high organic vapors at room temperature. In comparison with other reported porous organic polymers, CTHPs have the advantages of low-cost, easy preparation, and high gas-adsorption performance, making them suitable for mass production and practical use in the future.

  5. Hybrid Mesoporous Silicas and Microporous POSS-Based Frameworks Incorporating Evaporation-Induced Self-Assembly

    Science.gov (United States)

    Li, Jheng-Guang; Chu, Wei-Cheng; Kuo, Shiao-Wei

    2015-01-01

    We fabricated a series of mesoporous silicas and mesoporous organosilicates with hierarchical porosity through evaporation-induced self-assembly using Pluronic F127 as a template in this study. We could tailor the mesophase of each mesoporous silica sample by varying the weight ratio of its two silica sources: tetraethyl orthosilicate (TEOS) and triethoxysilane hydrosilylated octavinyl polyhedral oligomeric silsesquioxane (OV-POSS-SILY). The mesophases ranged from an ordered body-centered cubic (bcc) structure (TEOS alone) to ordered face-centered cubic (fcc) structure (10 and 20 wt.% of OV-POSS-SILY) and finally to disordered spherical pores (≥30 wt.% of OV-POSS-SILY). We used small-angle X-ray scattering (SAXS) and transmission electron microscopy (TEM) to study the transformations of these mesophases, while N2 isotherm sorption curves revealed the porosities of these mesoporous silicate samples. Moreover, 29Si CP/MAS solid state nuclear magnetic resonance spectroscopy allowed us to analyze the compositions of the POSS-containing silicate frameworks. Such functional mesoporous silica samples incorporating microporous POSS building units have potential applications in various systems, including optical and electronic devices.

  6. Estimation of diffusion anisotropy in microporous crystalline materials and optimization of crystal orientation in membranes.

    Science.gov (United States)

    Gounaris, Chrysanthos E; First, Eric L; Floudas, Christodoulos A

    2013-09-28

    The complex nature of the porous networks in microporous materials is primarily responsible for a high degree of intracrystalline diffusion anisotropy. Although this is a well-understood phenomenon, little attention has been paid in the literature with regards to classifying such anisotropy and elucidating its effect on the performance of membrane-based separation systems. In this paper, we develop a novel methodology to estimate full diffusion tensors based on the detailed description of the porous network geometry through our recent advances for the characterization of such networks. The proposed approach explicitly accounts for the tortuosity and complex connectivity of the porous framework, as well as for the variety of diffusion regimes that may be experienced by a guest molecule while it travels through the different localities of the crystal. Results on the diffusion of light gases in silicalite demonstrate good agreement with results from experiments and other computational techniques that have been reported in the literature. A comprehensive computational study involving 183 zeolite frameworks classifies these structures in terms of a number of anisotropy metrics. Finally, we utilize the computed diffusion tensors in a membrane optimization model that determines optimal crystal orientations. Application of the model in the context of separating carbon dioxide from nitrogen demonstrates that optimizing crystal orientation can offer significant benefit to membrane-based separation processes.

  7. PREPARATION OF EVOH MICROPOROUS MEMBRANES via THERMALLY INDUCED PHASE SEPARATION USING BINARY SOLVENTS

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    Microporous ethylene-vinyl alcohol copolymer (EVOH) flat membranes and hollow-fiber membranes with 38 mol% ethylene content were prepared via thermally induced phase separation (TIPS) using the mixture of 1,4-butanediol and poly(ethylene glycol)(PEG400) as diluents. Effects of the ratio of 1,4-butanediol to PEG400 on the phase diagrams, phase separation mechanism and membrane morphology were studied by small angle light scattering (SALS) measurements, differential scanning calorimetry (DSC), and scanning electron microscopy (SEM). It was found that by varying the composition of the binary solvent, the phase diagrams and membrane morphology can be controlled successfully. Moreover, the phase diagrams showed that broader regions of Liquid-Liquid (L-L) phase separation were obtained, as well as closer distances between L-L phase separation lines and Solid-Liquid (S-L) phase separation lines. Interconnected structures observed both in the flat membrane and hollow fiber membrane consist with the above results.

  8. Fabrication of chitosan/gallic acid 3D microporous scaffold for tissue engineering applications.

    Science.gov (United States)

    Thangavel, Ponrasu; Ramachandran, Balaji; Muthuvijayan, Vignesh

    2016-05-01

    This study explores the potential of gallic acid incorporated chitosan (CS/GA) 3D scaffolds for tissue engineering applications. Scaffolds were prepared by freezing and lyophilization technique and characterized. FTIR spectra confirmed the presence of GA in chitosan (CS) gel. DSC and TGA analysis revealed that the structure of chitosan was not altered due to the incorporation of GA, but thermal stability was significantly increased compared to the CS scaffold. SEM micrographs showed smooth, homogeneous, and microporous architecture of the scaffolds with good interconnectivity. CS/GA scaffolds exhibited approximately 90% porosity on average, increased swelling (600-900%) and controlled biodegradation (15-40%) in PBS (pH 7.4 at 37°C) with 1 mg/mL of lysozyme. CS/GA scaffolds showed 2-4 fold decrease in CFUs (p < 0.05) for both gram positive and gram negative bacteria compared to the CS scaffold. Cytotoxicity of these scaffolds was evaluated using NIH 3T3 L1 fibroblast cells. CS/GA 0.25% scaffold showed similar viability with CS scaffold at 24 and 48 h. CS/GA scaffolds (0.5-1.0%) showed 60-75% viability at 24 h and 90% at 48 h. SEM images showed that an increased cell attachment was observed for CS/GA scaffolds compared to CS scaffolds. These findings authenticate that CS/GA scaffolds were cytocompatible and would be useful for tissue engineering applications.

  9. Bifunctionalized Intrinsically Microporous Polyimides with Simultaneously Enhanced Gas Permeability and Selectivity

    KAUST Repository

    Ma, Xiaohua

    2016-03-29

    Two novel intrinsically microporous copolyimides synthesized by condensation reaction of 4,4′-(hexafluoroisopropylidene) diphthalic anhydride (6FDA), 3,3,3′,3′-tetramethyl-1,1′-spirobisindane-5,5′-diamino-6,6′-diol, and 3,5-diaminobenzoic acid with diamine ratios of 80/20 (Co-80/20) and 50/50 (Co-50/50) are reported. Unexpectedly, the Co-80/20 not only demonstrates higher microporosity (300 m2 g−1) than the PIM-6FDA-OH homopolymer (190 m2 g−1) but also exhibits simultaneously enhanced CO2 permeability (from 119 to 171 Barrer) and CO2/CH4 selectivity (from 35 to 41) after thermal annealing at 250 °C. This higher permeability originates from enhanced diffusivity (D CO2) and the higher selectivity results from its increased diffusion selectivity (D CO2/D CH4). After crosslinking at 300 °C, the Co-80/20 exhibits an even higher CO2 permeability (261 Barrer) and almost unchanged CO2/CH4 selectivity.

  10. Synthesis, characterization and quantitative analysis of porous metal microstructures: Application to microporous copper produced by solid state foaming

    Directory of Open Access Journals (Sweden)

    Mark A. Atwater

    2016-05-01

    Full Text Available Porous metals can be created through a wide variety of processing techniques, and the pore morphology resulting from these processes is equally diverse. The structural and functional properties of metal foams are directly dependent on the size, shape, interconnectedness and volume fraction of pores, so accurately quantifying the pore characteristics is of great importance. Methods for analyzing porous materials are presented here and applied to a copper-based metallic foam generated through solid state foaming via oxide reduction and expansion. This process results in large voids (10s of microns between sintered particles and small pores (10 microns to less than 50 nm within particles. Optical and electron microscopy were used to image the porosity over this wide range, and the pore characteristics were quantified using image segmentation and statistical analysis. Two-dimensional pore analysis was performed using the Chan-Vese method, and two-point correlation and lineal path functions were used to assess three-dimensional reconstructions from FIB tomography. Two-dimensional analysis reveals distinct size and morphological differences in porosity between particles and within them. Three-dimensional analysis adds further information on the high level interconnectedness of the porosity and irregular shape it takes, forming tortuous pathways rather than spherical cells. Mechanical polishing and optical microscopy allow large areas to be created and analyzed quickly, but methods such as focused ion beam (FIB sectioning can provide additional insight about microstructural features. In particular, after FIB milling is used to create a flat surface, that surface can be analyzed for structural and compositional information.

  11. Microporous heptazine functionalized (3,24)-connected rht-metal-organic framework: Synthesis, structure, and gas sorption analysis

    KAUST Repository

    Luebke, Ryan

    2014-02-05

    Here we synthesized the highly porous rht-MOF-9 as the first example of an rht-MOF having a polycyclic central core. This material was synthesized from a predesigned polyheterocyclic nitrogen-rich hexacarboxylate (tri-isophthalate) ligand, which serves as the 3-connected, trigonal molecular building block (MBB). When reacted under the proper conditions, this ligand, having three coplanar isophthalic acid moieties, codes for the in situ formation of the targeted 24-connected copper-based supermolecular building block (SBB) having rhombicuboctahedral geometry. This combination of a 24-connected building block linked through 3-connected nodes results in a novel material with the singular rht topology. The rht-MOF-9 compound exhibits promising H2 and CO2 adsorption properties in comparison to previously reported rht-MOFs. © 2014 American Chemical Society.

  12. Bioresorbable microporous stents deliver recombinant adenovirus gene transfer vectors to the arterial wall.

    Science.gov (United States)

    Ye, Y W; Landau, C; Willard, J E; Rajasubramanian, G; Moskowitz, A; Aziz, S; Meidell, R S; Eberhart, R C

    1998-01-01

    The use of intravascular stents as an adjunct for percutaneous transluminal revascularization is limited by two principal factors, acute thrombosis and neointimal proliferation, resulting in restenosis. To overcome these limitations, we have investigated the potential of microporous bioresorbable polymer stents formed from poly(L-lactic acid) (PLLA)/poly(epsilon-caprolactone) (PCL) blends to function both to provide mechanical support and as reservoirs for local delivery of therapeutic molecules and particles to the vessel wall. Tubular PLLA/PCL stents were fabricated by the flotation-precipitation method, and helical stents were produced by a casting/winding technique. Hybrid structures in which a tubular sheath is deposited on a helical skeleton were also generated. Using a two-stage solvent swelling technique, polyethylene oxide has been incorporated into these stents to improve hydrophilicity and water uptake, and to facilitate the ability of these devices to function as drug carriers. Stents modified in this manner retain axial and radial mechanical strength sufficient to stabilize the vessel wall against elastic recoil caused by vasoconstrictive and mechanical forces. Because of the potential of direct gene transfer into the vessel wall to ameliorate thrombosis and neointimal proliferation, we have investigated the capacity of these polymer stents to function in the delivery of recombinant adenovirus vectors to the vessel wall. In vitro, virus stock was observed to readily absorb into, and elute from these devices in an infectious form, with suitable kinetics. Successful gene transfer and expression has been demonstrated following implantation of polymer stents impregnated with a recombinant adenovirus carrying a nuclear-localizing betaGal reporter gene into rabbit carotid arteries. These studies suggest that surface-modified polymer stents may ultimately be useful adjunctive devices for both mechanical support and gene transfer during percutaneous

  13. Vapor-Particle Separation Using Microporous Metallic Membrane in Crossflow Filtration

    Energy Technology Data Exchange (ETDEWEB)

    Cheng, Mengdawn [ORNL

    2013-01-01

    Simultaneous separation of vapor and particles in industrial processes could be a key step toward manufacturing of high-quality goods. The separation is critical for successful measurement of volatile or semi-volatile aerosol particles, which no reliable technique exists. We have developed a technique for separation of vapor and particles simultaneously using a specialty microporous metallic membrane. The separator allows the thermally denuded particles traverse straight through the membrane tube, while the vapor molecules permeate through the membrane, separate from the particles and are removed subsequently. The separation technique virtually eliminates the possibility of contamination by vapor re- condensation. We tested the prototype of the vapor-particle separator (VPS) using aerosols prepared from sodium chloride to represent non-volatile aerosols. Chemical like dioctyl phthalate was chosen to represent volatile particles. The test aerosol particles were generated by an atomizer followed by a tandem differential mobility analyser to produce a stream of monodisperse particles in the size range of 10 to 100 nm. In real world particles, we tested the VPS using diesel engine particles that is a mixture of complex chemical composition. Number concentration of the nonvolatile particles reduced as the temperature increased, but the mode diameter of the aerosol population remained unchanged. Number concentration of the volatile particles was also reduced as the temperature increased, but their mode diameters became smaller as particles shrunk in diameter. Differences in the thermal behaviour of the particles were attributed to its transition energy barrier and evaporation rate. Mass balance analysis suggests the separation of vapor and test particles was reasonably complete. Thus, we conclude the VPS could provide an effective means for quantitative characterization of aerosol volatility and separation of vapors from particles.

  14. Protein adsorption in two-dimensional electrochromatography packed with superporous and microporous cellulose beads

    Institute of Scientific and Technical Information of China (English)

    Dongmei WANG; Guodong JIA; Liang XU; Xiaoyan DONG; Yan SUN

    2009-01-01

    Anion-exchange superporous cellulose (DEAE-SC) and microporous cellulose (DEAE-MC) adsorbents were packed in an electrochromatographic column, and the effect of external electric field (eEF) on the dynamic adsorption was investigated. The column was designed to provide longitudinal, transverse or 2-dimensional (2D) eEF. It was found that the electro-kinetic effect caused by the introduction of an electric field played an important role in the dynamic adsorption of bovine serum albumin to the adsorbents. The dynamic binding capacity (DBC) in the presence of2D eEF was higher than in the presence of a one-dimensional eEF. The effect of flow velocity on the DBC of the two adsorbents was also demonstrated. It was found that the effect of electric field. on the DEAE-MC column was more remarkable than that on the DEAE-SC column at the same flow rate, whereas the DEAE-SC column showed higher DBC and adsorption efficiency (AE) than the DEAE-MC column. With increasing flow rate, the DEAE-SC column could still offer high DBC and AE in the presence of the 2D eEF. For example, a DBC of 21.4 mg/mL and an AE of 57.7% were obtained even at a flow rate as high as 900 cm/h. The results indicate that the 2D electrochromatography packed with the superporous cellulose adsorbent is promising for high-speed protein chromatography.

  15. Peri- and intra-implant bone response to microporous Ti coatings with surface modification.

    Science.gov (United States)

    Braem, Annabel; Chaudhari, Amol; Vivan Cardoso, Marcio; Schrooten, Jan; Duyck, Joke; Vleugels, Jozef

    2014-02-01

    Bone growth on and into implants exhibiting substantial surface porosity is a promising strategy in order to improve the long-term stable fixation of bone implants. However, the reliability in clinical applications remains a point of discussion. Most attention has been dedicated to the role of macroporosity, leading to the general consensus of a minimal pore size of 50-100 μm in order to allow bone ingrowth. In this in vivo study, we assessed the feasibility of early bone ingrowth into a predominantly microporous Ti coating with an average thickness of 150 μm and the hypothesis of improving the bone response through surface modification of the porous coating. Implants were placed in the cortical bone of rabbit tibiae for periods of 2 and 4 weeks and evaluated histologically and histomorphometrically using light microscopy and scanning electron microscopy. Bone with osteocytes encased in the mineralized matrix was found throughout the porous Ti coating up to the coating/substrate interface, highlighting that osseointegration of microporosities (<10 μm) was achievable. The bone trabeculae interweaved with the pore struts, establishing a large contact area which might enable an improved load transfer and stronger implant/bone interface. Furthermore, there was a clear interconnection with the surrounding cortical bone, suggesting that mechanical interlocking of the coating in the host bone in the long term is possible. When surface modifications inside the porous structure further reduced the interconnective pore size to the submicrometer level, bone ingrowth was impaired. On the other hand, application of a sol-gel-derived bioactive glass-ceramic coating without altering the pore characteristics was found to significantly improve bone regeneration around the coating, while still supporting bone ingrowth. Copyright © 2013 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

  16. Evaluation of microporous polycaprolactone matrices for controlled delivery of antiviral microbicides to the female genital tract.

    Science.gov (United States)

    Asvadi, Naghme Hajarol; Dang, Nhung T T; Davis-Poynter, Nicholas; Coombes, Allan G A

    2013-12-01

    Acyclovir (ACV) as a model antiviral microbicide, was incorporated in controlled-release polycaprolactone (PCL) matrices designed for application as intra-vaginal ring inserts (IVRs). Microporous materials incorporating acyclovir up to a level of ~10 % w/w were produced by rapidly cooling suspensions of drug powder in PCL solution followed by solvent extraction from the hardened matrices. Around 21, 50 and 78 % of the drug content was gradually released from matrices over 30 days in simulated vaginal fluid at 37 °C, corresponding to drug loadings of 5.9, 7.0 and 9.6 % w/w. The release behaviour of matrices having the lowest drug loading followed a zero order model, whereas, the release kinetics of 7.0 and 9.6 % ACV-loaded PCL matrices could be described effectively by the Higuchi model, suggesting that Fickian diffusion is controlling drug release. Corresponding values of the diffusion co-efficient for ACV in the PCL matrices of 3.16 × 10(-9) and 1.07 × 10(-8) cm(2)/s were calculated. Plaque reduction assays provided an IC50 value of 1.09 μg/mL for acyclovir against HSV-2 and confirmed the antiviral activity of released acyclovir against HSV-2 replication in primate kidney cells (Vero) at levels ~70 % that of non-formulated acyclovir at day 30. Estimated minimum in vivo acyclovir concentrations produced by a PCL IVR (19 μg/mL) exceeded by a factor of 20 the IC50 value against HSV-2 and the reported ACV vaginal concentrations in women (0.5-1.0 μg/mL) following oral administration. These findings recommend further investigations of PCL matrices for vaginal delivery of antiviral agents in the treatment and prevention of sexually transmitted infections such as AIDS.

  17. Hierarchically microporous/macroporous scaffold of magnesium-calcium phosphate for bone tissue regeneration.

    Science.gov (United States)

    Wei, Jie; Jia, Junfeng; Wu, Fan; Wei, Shicheng; Zhou, Huanjun; Zhang, Hongbo; Shin, Jung-Woog; Liu, Changsheng

    2010-02-01

    Hierarchically 3D microporous/macroporous magnesium-calcium phosphate (micro/ma-MCP) scaffolds containing magnesium ammonium phosphate hexahydrate [NH(4)MgPO(4).6H(2)O] and hydroxyapatite [Ca(10)(PO(4))(6)(OH)(2)] were fabricated from cement utilizing leaching method in the presence of sodium chloride (NaCl) particles and NaCl saturated water solution. NaCl particles produced macroporosity, and NaCl solution acted as both cement liquid and porogens, inducing the formation of microporosity. The micro/ma-MCP scaffolds with porosities varied from 52 to 78% showed well interconnected and open macropores with the sizes of 400-500 microm, and degradation of the scaffolds was significantly enhanced in Tris-HCl solution compared with macroporous MCP (ma-MCP) and corresponding calcium phosphate cement (CPC) scaffolds. Cell attachment and proliferation of MG(63) on micro/ma-MCP were significantly better than ma-MCP and CPC scaffolds because of the presence of microporosity, which enhanced the surface area of the scaffolds. Moreover, the alkaline phosphatase (ALP) activity of the MG(63) cells on micro/ma-MCP was significantly higher than ma-MCP and CPC scaffolds at 7 days, and the MG(63) cells with normal phenotype spread well and formed confluent layers across the macroporous walls of the micro/ma-MCP scaffolds. Histological evaluation confirmed that the micro/ma-MCP scaffolds improved the efficiency of new bone regeneration, and exhibited excellent biocompatibility, biodegradability and faster and more effective osteogenesis in vivo.

  18. Nitrogen doped microporous carbon by ZnCl2 activation of protein

    Science.gov (United States)

    Wilson, Praveen; Vijayan, Sujith; Prabhakaran, K.

    2017-09-01

    ZnCl2 activation of protein containing biomass has been studied for the preparation of N-doped activated carbon (NDC) using powdered dry fish as a source of protein. Nearly 52% increase in the yield of NDC is observed by activation with ZnCl2 due to an increase in the thermal stability of Zn2+-fish protein complex compared to the protein alone. The NDCs obtained are characterized by XRD, IR, XPS, Raman spectroscopy, SEM, TEM, elemental analysis and N2 adsorption–desorption studies. The activation at 550 °C produces NDC with the highest surface area and total pore volume of 1001 m2 g‑1 and 0.719 cm3 g‑1, respectively, at a ZnCl2 to fish powder weight ratio of 3. A maximum micropore volume of 0.273 cm3 g‑1 is obtained at a ZnCl2 to fish powder weight ratio of 1:1. The N-content (12.4–5.2 wt%) decreases with an increase in activation temperature and ZnCl2 to fish powder weight ratio. The NDC obtained by activation at 550 °C at a ZnCl2 to fish powder weight ratio of 1:1 shows the maximum CO2 adsorption capacity of 2.4 and 3.73 mmol g‑1 at 25 and 0 °C, respectively, at 1 atmosphere. The CO2 adsorption on the NDC shows excellent cyclic stability and high selectivity over nitrogen gas.

  19. Long-term result of guided nerve regeneration with an inert microporous polytetrafluoroethylene conduit

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    Objective: To evaluate the long-term outcome of Polytetrafluoroethylene (PTFE) conduit in nerve repair and to provide more evidence in view of its potential application to achieve a satisfactory functional recovery in clinical settings. Methods: Thirty-six Wistar rats had their right sciatic nerve transected and were repaired with either conventional microsuture technique (Control group, n=18) or a PTFE conduit with a gap of 5 mm left between the nerve stumps (PTFE group, n=18). At 6 and 9 months after the operation, electrophysiological assessment and measurement of gastrocnemius muscle weight were conducted and morphology of the regenerated nerves were studied with image analysis. Results: At 6 months postoperatively, the nerve conduction velocity recovered to 60.86% and 54.36% (P>0.05), and the gastrocnemius muscle weight recovered to 50.89% and 46.11% (P>0.05) in the Control group and the PTFE group respectively. At 9 months postoperatively, the recovery rate was 65.99% and 58.79% for NCV (P>0.05), and 52.56% and 47.89% for gastrocnemius muscle weight (P>0.05) in the Control group and the PTFE group respectively. Regenerated nerve fibers in the PTFE group had a regular round shape with no fragmentation, wrinkling or splitting of the myelin sheath. Image analysis revealed that the ratio of the myelin area to the total fiber area was larger at 9 months than at 6 months in both groups (P<0.01). Conclusions: Microporous PTFE conduit may be an alternative for nerve repair allowing of guided nerve regeneration and functional recovery with no obvious adverse effect at long-term.

  20. Phase-field simulation of micropores constrained by the dendritic network during solidification

    Energy Technology Data Exchange (ETDEWEB)

    Meidani, H., E-mail: hossein.meidani@epfl.ch [Computational Materials Laboratory, Institute of Materials, Ecole Polytechnique Federale de Lausanne, 1015 Lausanne (Switzerland); Jacot, A. [Computational Materials Laboratory, Institute of Materials, Ecole Polytechnique Federale de Lausanne, 1015 Lausanne (Switzerland); Calcom ESI SA, Parc Scientifique, PSE-A, 1015 Lausanne (Switzerland)

    2011-05-15

    Highlights: > Direct description of the complex morphology of micropores in using phase-field. > Presence of solid substantially influences the pressure and volume of the pores. > Hydrogen content is an influencing factor that was not considered previously. > Pore curvature depends on the statistical distribution of liquid channel widths. - Abstract: A phase-field model has been developed to describe the morphology of pores constrained by a dendritic solid network, and are forced to adopt complex non-spherical shapes. The distribution of the solid, liquid and gas phases was calculated with a multiphase-field approach which accounts for the pressure difference between the liquid and the gas. The model considers the partitioning of the dissolved gas at interfaces, gas diffusion and capillary forces at the solid/liquid, liquid/gas and gas/solid interfaces. The model was used to study the influence of the dendrite arm spacing (DAS) and the solid fraction on the state of a pore. The calculations show that a pore constrained to grow in a narrow liquid channel exhibits a substantially higher mean curvature, a larger pressure and a smaller volume than an unconstrained pore. Comparisons with simple geometrical models indicate that analytical approaches show a good trend but tend to underestimate the pore curvature, in particular at high solid fractions, where pores have to penetrate the thin liquid channels. For pores spanning over distances larger than the average DAS, the simulations showed that the radius of curvature can vary between two limits, which are given by the size of the narrowest section that the pore needs to pass in order to expand and by the largest sphere that can be fitted in the interdendritic liquid. The pore curvature is therefore a complex non-monotonic function of the DAS, the solid fraction, the hydrogen content and statistical variations of the liquid channel width.

  1. Preparation of nitrogen-doped cotton stalk microporous activated carbon fiber electrodes with different surface area from hexamethylenetetramine-modified cotton stalk for electrochemical degradation of methylene blue

    Science.gov (United States)

    Li, Kunquan; Rong, Zhang; Li, Ye; Li, Cheng; Zheng, Zheng

    Cotton-stalk activated carbon fibers (CSCFs) with controllable micropore area and nitrogen content were prepared as an efficient electrode from hexamethylenetetramine-modified cotton stalk by steam/ammonia activation. The influence of microporous area, nitrogen content, voltage and initial concentration on the electrical degradation efficiency of methylene blue (MB) was evaluated by using CSCFs as anode. Results showed that the CSCF electrodes exhibited excellent MB electrochemical degradation ability including decolorization and COD removal. Increasing micropore surface area and nitrogen content of CSCF anode leaded to a corresponding increase in MB removal. The prepared CSCF-800-15-N, which has highest N content but lowest microporous area, attained the best degradation effect with 97% MB decolorization ratio for 5 mg/L MB at 12 V in 4 h, implying the doped nitrogen played a prominent role in improving the electrochemical degradation ability. The electrical degradation reaction was well described by first-order kinetics model. Overall, the aforesaid findings suggested that the nitrogen-doped CSCFs were potential electrode materials, and their electrical degradation abilities could be effectively enhanced by controlling the nitrogen content and micropore surface area.

  2. 微孔聚酰亚胺的研究进展%Research Progress of Microporous Polyimide

    Institute of Scientific and Technical Information of China (English)

    张海玲; 许云书

    2012-01-01

    微孔聚酰亚胺不仅具有聚酰亚胺的低介电、耐高低温等特性,而且兼备了微孔材料的密度小、质轻等诸多优点,起始分解温度一般在250℃以上,介电常数一般在2.5左右,平均密度一般小于0.3g/cm3,在航空航天、微电子领域都有应用前景.综述了微孔聚酰亚胺的制备方法,结合耐热性能、力学性能、介电常数、吸声性能等的表征,总结了微孔聚酰亚胺的研究方法,并展望了微孔聚酰亚胺的应用前景.%Microporous polyimide not only has the properties of polyimide such as low dielectric, high temperature resistance, but also has low density, light weight, and many other advantages of the microporous materials. Its starting decomposition temperature is above 25O℃ commonly, dielectric constant is about 2. 5 in general and the average density is less than 0. 3g/cm3. In addition, it has application prospect in aerospace and microelectronics area. The preparation method of the microporous polyimide is reviewed, the characterization methods of the properties such as heat resistance, mechanical strength, dielectric constant, sound absorption and other aspects are summarized, and the application prospect of microporous polyimide is discussed.

  3. Blocked-micropores, surface functionalized, bio-compatible and silica-coated iron oxide nanocomposites as advanced MRI contrast agent

    Energy Technology Data Exchange (ETDEWEB)

    Darbandi, Masih, E-mail: masih.darbandi@uni-due.de [Vanderbilt University, Department of Physics and Vanderbilt Institute of Nanoscale Science and Engineering (VINSE) (United States); Laurent, Sophie [University of Mons, Department of General, Organic and Biomedical Chemistry NMR and Molecular Imaging Laboratory (Belgium); Busch, Martin [University of Duisburg-Essen, Nanoparticle Process Technology, Faculty of Engineering and Center for Nanointegration Duisburg-Essen (CeNIDE) (Germany); Li Zian [University of Duisburg-Essen, Faculty of Physics and Center for Nanointegration Duisburg-Essen (CeNIDE) (Germany); Yuan Ying; Krueger, Michael [University of Freiburg, Department of Microsystems Engineering and Freiburg Materials Research Centre (Germany); Farle, Michael [University of Duisburg-Essen, Faculty of Physics and Center for Nanointegration Duisburg-Essen (CeNIDE) (Germany); Winterer, Markus [University of Duisburg-Essen, Nanoparticle Process Technology, Faculty of Engineering and Center for Nanointegration Duisburg-Essen (CeNIDE) (Germany); Vander Elst, Luce; Muller, Robert N. [University of Mons, Department of General, Organic and Biomedical Chemistry NMR and Molecular Imaging Laboratory (Belgium); Wende, Heiko [University of Duisburg-Essen, Faculty of Physics and Center for Nanointegration Duisburg-Essen (CeNIDE) (Germany)

    2013-05-15

    Biocompatible magnetic nanoparticles have been found promising in several biomedical applications for tagging, imaging, sensing and separation in recent years. In this article, a systematic study of the design and development of surface-modification schemes for silica-coated iron oxide nanoparticles (IONP) via a one-pot, in situ method at room temperature is presented. Silica-coated IONP were prepared in a water-in-oil microemulsion, and subsequently the surface was modified via addition of organosilane reagents to the microemulsion system. The structure and the morphology of the as synthesized nanoparticles have been investigated by means of transmission electron microscopy (TEM) and measurement of N{sub 2} adsorption-desorption. Electron diffraction and high-resolution transmission electron microscopic (TEM) images of the nanoparticles showed the highly crystalline nature of the IONP structures. Nitrogen adsorption indicates microporous and blocked-microporous structures for the silica-coated and amine functionalized silica-coated IONP, respectively which could prove less cytotoxicity of the functionalized final product. Besides, the colloidal stability of the final product and the presence of the modified functional groups on top of surface layer have been proven by zeta-potential measurements. Owing to the benefit from the inner IONP core and the hydrophilic silica shell, the as-synthesized nanocomposites were exploited as an MRI contrast enhancement agent. Relaxometric results prove that the surface functionalized IONP have also signal enhancement properties. These surface functionalized nanocomposites are not only potential candidates for highly efficient contrast agents for MRI, but could also be used as ultrasensitive biological-magnetic labels, because they are in nanoscale size, having magnetic properties, blocked-microporous and are well dispersible in biological environment.

  4. Applicability of the theory of volume filling of micropores to adsorption of caprolactam from aqueous solutions with active carbons

    Energy Technology Data Exchange (ETDEWEB)

    Khodorov, E.I.; Kazakov, V.A.; Semerikova, V.V.; Surinova, S.I.

    1985-06-10

    The absence of a scientifically based method of selecting adsorbents in the extraction of organic substances from waste water and solution which would allow for their multicycle use in adsorption-desorption stages often prevents the introduction of adsorption technology into industrial practice. This paper demonstrates the possibility of calculating the adsorption equilibrium of highly soluble organic compounds with the theory of volume filling of micropores equations in consideration of the activities of the extracted component in the solution and the change in the partial affinity coefficient with the degree of filling of the adsorption volume on the example of extraction of caprolactam from aqueous solutions.

  5. The moisture-triggered controlled release of a natural food preservative from a microporous metal-organic framework.

    Science.gov (United States)

    Wang, Hao; Lashkari, Elham; Lim, Hyuna; Zheng, Chong; Emge, Thomas J; Gong, Qihan; Yam, Kit; Li, Jing

    2016-02-01

    In this work we demonstrate that allyl isothiocyanate (AITC), a common food flavoring agent and food preservative, can be effectively captured by and released in a controlled manner from a microporous metal-organic framework (MOF). The extent of AITC-MOF interactions is quantitatively measured by orbital overlap population calculations. Controlled release experiments show that loaded AITC can be released by applying higher relative humidity. Further analysis reveals that the underlying mechanism of the controlled release is associated with the transformation of the MOF from a porous to a nonporous structure at high humidity. This study represents the first example of making use of MOF porosity in food preservation.

  6. Microporous Metal-Organic Framework Based on Ligand-Truncation Strategy with High Performance for Gas Adsorption and Separation.

    Science.gov (United States)

    Liu, Jianqiang; Wang, Wenjing; Luo, Zhidong; Li, Baohong; Yuan, Daqiang

    2017-09-05

    By using the ligand-truncation strategy, a microporous metal-organic framework (1) with high surface area was designedly synthesized. MOF 1 shows a new (4, 4)-connected net with a Schläfli symbol of (4(4).6(2))(4(3).6(2).8)2(4(2).8(2).10(2)) and exhibits a high H2 capture capacity (193 cm(3) g(-1) at 1 atm and 77 K) and selectivities for CO2 over N2 and CH4 at low pressure.

  7. Preparation and Characterization of Microporous Nano-Tungsten Trioxide and Its Photocatalytic Activity after Doping Rare Earth

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    Aqueous sols and gels of tungstic acid were prepared from Na2WO4 with protonated cation-exchange resin. Nano-tungsten oxide of a microporous lamella was synthesized by means of washing of WO3*2H2O with distilled water under ultrasonic wave agitation and centrifuging repeatedly, and the specific surface area tended to increase gradually with washing and centrifuging. The sample of centrifuged 7 h has more than 2 times highs specific surface area and more high photocatalytic activity . The mechanisms are also discussed.

  8. Effect of Adsorbed Protein on the Hydraulic Permeability, Membrane and Streaming Potential Values Measured across a Microporous Membrane

    DEFF Research Database (Denmark)

    Benavente, Juana; Jonsson, Gunnar Eigil

    1998-01-01

    different experimental conditions may be attributed to different mechanisms for the adsorption of proteins in the membrane: (i) a protein deposition on the membrane pores; () an adsorbed layer of protein on the membrane surface. In this latter case, the whole membrane system can be considered......The effect of the adsorption of a protein, bovine serum albumin (BSA), on the membrane potential, flux reduction and streaming potential measured across a microporous polysulphone membrane with different NaCl solutions and pH values is studied. From electrokinetic phenomena, information about...

  9. Effect of coadsorbed CO 2 on the magnetic properties of O 2 confined in graphitic slit-shaped micropores

    Science.gov (United States)

    Tohdoh, A.; Kaneko, K.

    2001-05-01

    The magnetic susceptibility of coadsorbed O 2 and CO 2 confined in a slit-shaped graphitic micropore was measured over the temperature range 2-300 K. Coadsorbed CO 2 markedly repressed the susceptibility of confined O 2 because CO 2 restricts the O 2 molecular arrangement to form spin clusters. Curie-Weiss plots show that the coadsorbed CO 2 reduced the effective spin concentration while the negative Weiss constant with CO 2 was larger than that of pure O 2. These results also indicate that the coadsorbed CO 2 promotes the formation of smaller clusters of O 2 molecules than for pure O 2.

  10. Nanoscale Fluorescent Metal-Organic Framework@Microporous Organic Polymer Composites for Enhanced Intracellular Uptake and Bioimaging.

    Science.gov (United States)

    Wang, Lei; Wang, Weiqi; Zheng, Xiaohua; Li, Zhensheng; Xie, Zhigang

    2017-01-26

    Polymer-modified metal-organic frameworks combine the advantages of both soft polymers and crystalline metal-organic frameworks (MOFs). It is a big challenge to develop simple methods for surface modification of MOFs. In this work, MOF@microporous organic polymer (MOP) hybrid nanoparticles (UNP) have been synthesized by epitaxial growth of luminescent boron-dipyrromethene (BODIPYs)-imine MOPs on the surface of UiO-MOF seeds, which exhibit low cytotoxicity, smaller size distribution, well-retained pore integrity, and available functional sites. After folic acid grafting, the enhanced intracellular uptake and bioimaging was validated.

  11. Shedding Light on Structure-Property Relationships for Conjugated Microporous Polymers: The Importance of Rings and Strain.

    Science.gov (United States)

    Zwijnenburg, Martijn A; Cheng, Ge; McDonald, Tom O; Jelfs, Kim E; Jiang, Jia-Xing; Ren, Shijie; Hasell, Tom; Blanc, Frédéric; Cooper, Andrew I; Adams, Dave J

    2013-10-08

    The photophysical properties of insoluble porous pyrene networks, which are central to their function, differ strongly from those of analogous soluble linear and branched polymers and dendrimers. This can be rationalized by the presence of strained closed rings in the networks. A combined experimental and computational approach was used to obtain atomic scale insight into the structure of amorphous conjugated microporous polymers. The optical absorption and fluorescence spectra of a series of pyrene-based materials were compared with theoretical time-dependent density functional theory predictions for model clusters. Comparison of computation and experiment sheds light on the probable structural chromophores in the various materials.

  12. Microwave-assisted Ionothermal Synthesis and Characteriza- tion of Zeolitic Imidazolate Framework-8

    Institute of Scientific and Technical Information of China (English)

    杨丽莎; 卢惠民

    2012-01-01

    The zeolitic imidazolate framework-8 (ZIF-8) was successfully synthesized using ionic liquids as struc- ture-directing agent under microwave irradiation. Ionic liquids are green solvents with low vapour pressure and good thermal stability. They are appropriate templates for microporous materials and ideal microwave absorbers. The microwave-assisted ionothermal synthesis applied in this paper was expected to be a promising method for the preparation of microporous materials. Results showed that the as-synthesized samples (300---500 nm in diameter) could be synthesized in a short time (60 min) and possessed regular morphology, stable structure and high thermal stability (up to 720 ~C in argon atmosphere). Nitrogen adsorption-desorption test illustrated that samples produced by microwave heating had a higher surface area. Carbon dioxide adsorption test indicated that the samples synthe- sized by microwave heating had better carbon dioxide adsorption ability than those by conventional heating.

  13. Preparation of a new micro-porous poly(methyl methacrylate)-grafted polyethylene separator for high performance Li secondary battery

    Energy Technology Data Exchange (ETDEWEB)

    Gwon, Sung-Jin [Radiation Research Division for Industry and Environment, Advanced Radiation Technology Institute, Korea Atomic Energy Research Institute, Jeongeup-si, Jeollabuk-do 580-185 (Korea, Republic of); Department of Materials Engineering, Chnugnam National University, Yuseong-gu, Daejeon 305-764 (Korea, Republic of); Choi, Jae-Hak; Sohn, Joon-Yong [Radiation Research Division for Industry and Environment, Advanced Radiation Technology Institute, Korea Atomic Energy Research Institute, Jeongeup-si, Jeollabuk-do 580-185 (Korea, Republic of); Ihm, Young-Eon [Department of Materials Engineering, Chnugnam National University, Yuseong-gu, Daejeon 305-764 (Korea, Republic of); Nho, Young-Chang [Radiation Research Division for Industry and Environment, Advanced Radiation Technology Institute, Korea Atomic Energy Research Institute, Jeongeup-si, Jeollabuk-do 580-185 (Korea, Republic of)], E-mail: ycnho@kaeri.re.kr

    2009-10-01

    In this study, micro-porous poly(methyl methacrylate)-grafted polyethylene separators (PE-g-PMMA) were prepared by a radiation-induced graft polymerization of methyl methacrylate onto a conventional PE separator followed by a phase inversion. After the phase inversion, the micro-pores were generated in the grafted PMMA layer. The prepared micro-porous PE-g-PMMA separators showed an improved electrolyte uptake and ionic conductivity due to their improved affinity with a liquid electrolyte and the presence of pores in the grafted PMMA layer. The PE-g-PMMA separators exhibited a lower thermal shrinkage compared to the original PE separator. The PE-g-PMMA separators showed a better oxidation stability up to 5.0 V when compared to the original PE separator (4.5 V)

  14. Preparation of a new micro-porous poly(methyl methacrylate)-grafted polyethylene separator for high performance Li secondary battery

    Science.gov (United States)

    Gwon, Sung-Jin; Choi, Jae-Hak; Sohn, Joon-Yong; Ihm, Young-Eon; Nho, Young-Chang

    2009-10-01

    In this study, micro-porous poly(methyl methacrylate)-grafted polyethylene separators (PE-g-PMMA) were prepared by a radiation-induced graft polymerization of methyl methacrylate onto a conventional PE separator followed by a phase inversion. After the phase inversion, the micro-pores were generated in the grafted PMMA layer. The prepared micro-porous PE-g-PMMA separators showed an improved electrolyte uptake and ionic conductivity due to their improved affinity with a liquid electrolyte and the presence of pores in the grafted PMMA layer. The PE-g-PMMA separators exhibited a lower thermal shrinkage compared to the original PE separator. The PE-g-PMMA separators showed a better oxidation stability up to 5.0 V when compared to the original PE separator (4.5 V).

  15. Micropore diffusion in coal chars under reactive conditions: Quarterly technical progress report, 15 December 1986-15 March 1987. [Effect of activated diffusion in small pores

    Energy Technology Data Exchange (ETDEWEB)

    Calo, J.M.; Perkins, M.T.; Lilly, W.D.

    1987-01-01

    In this second quarterly technical progress report, we present some additional developments concerning the analysis of the effect of activated micropore diffusion on gasification reactivity, and report on progress with the experimental apparatus: (1) The Autoclave Engineers 3'' Berty catalytic reactor has been reassembled and tested, and has been found to function satisfactorily. However, the mass spectrometer malfunctioned and had to be repaired. (2) The effect of sorbate partial pressure on miropore diffusion and gasification reactivity have been examined. It was found that: pressure can have a significant effect on micropore diffusivities; increasing pressure generally increases the microparticle effectiveness factor for pressures far from saturation (while the opposite is true at near-saturation conditions); and the effect of sorbate partial pressure should be considered in conducting and interpreting measurements regarding micropore diffusion. 6 refs., 1 fig., 1 tab.

  16. Nitrogen-doped MOF-derived micropores carbon as immobilizer for small sulfur molecules as a cathode for lithium sulfur batteries with excellent electrochemical performance.

    Science.gov (United States)

    Li, Zhaoqiang; Yin, Longwei

    2015-02-25

    Nitrogen-doped carbon (NDC) spheres with abundant 22 nm mesopores and 0.5 nm micropores are obtained by directly carbonization of nitrogen-contained metal organic framework (MOF) nanocrystals. Large S8 and small S2-4 molecules are successfully infiltrated into 22 nm mesopores and 0.5 nm micropores, respectively. We successfully investigate the effect of sulfur immobilization in mesopores and micropores on the electrochemical performance of lithium-sulfur (Li-S) battery based on NDC-sulfur hybrid cathodes. The large S8 molecules in 22 nm mesopores can be removed by a prolonged heat treatment, with only small molecules of S2-4 immobilized in micropores of NDC matrices. The NDC/S2-4 hybrid exhibits excellent cycling performance, high Coulombic efficiency, and good rate capability as cathode for Li-S batteries. The confinement of smaller S2-4 molecules in the micropores of NDS efficiently avoids the loss of active sulfur and formation of soluble high-order Li polysulfides. The porous carbon can buffer the volume expansion and contraction changes, promising a stable structure for cathode. Furthermore, N doping in MOF-derived carbon not only facilitates the fast charge transfer but also is helpful in building a stronger interaction between carbon and sulfur, strengthening immobilization ability of S2-4 in micropores. The NDS-sulfur hybrid cathode exhibits a reversible capacity of 936.5 mAh g(-1) at 100th cycle with a Coulombic efficiency of 100% under a current density of 335 mA g(-1). It displays a superior rate capability performance, delivering a capacity of 632 mAh g(-1) at a high rate of 5 A g(-1). This uniquely porous NDC derived from MOF nanocrystals could be applied in related high-energy storage devices.

  17. Theoretical study on the 4-angstrom carbon nanotube growth mechanisms inside microporous aluminum phosphate-5

    Science.gov (United States)

    Liu, Jianwen

    The growth mechanisms of mono-sized and parallel-aligned single wall carbon nanotube (CNT) in the microporous channels of AlPO4-5 are investigated by density functional theory calculations. Detailed mechanisms are proposed for the decomposition of TPA, the formation of aromatic ring, and the growth of carbon nanotubes. In the first part, the mechanisms for the dissociation of TPA are studied under three types of conditions. The unimolecular dissociation is initiated by the breaking of either the N-Calpha and Calpha -Cbeta bonds and leads to many complicated processes. Within the confined space inside neutral zeolite channels, the diffusion of H radicals enhances a cycle of reactions, which accounts for the experimental observation of dipropylamine and monopropylamine. In the presence of an acidic site, the dissociation of TPA goes through catalyzed successive steps to produce ammonia and propylene molecules. In the second part, A T5 cluster model is used to investigate mechanisms of propylene aromatization to benzene, which involves chemisorption, dimerization, cyclization and dehydrogenation. Propylene can be chemisorbed to form two distinct products, n-propoxide and i-propoxide, which can further be dimerizated to form longer chain olefins 1-hexene and 2-hexene (from n-propoxide), and 4-methyl-1-pentene and 4-methyl-2-penetene (from i-propoxide). Initiated by H2 elimination, these dimerization products can further go through cyclization process to generated either 6-member ring cyclohexene or 5-member ring methyl-cyclopentene. Catalyzed by zeolite, cyclohexene can directly dehydrogenate to form benzene whereas methyl-cyclopentene can dehydrogenate to form fulven, an isomer to benzene. Under acidic zeolite environment, a fulvene can readily be transformed to the thermodynamically more stable benzene. In the last part, two distinct paths are proposed to investigate the carbon nanotube growth mechanism using benzene as the growth seed and propylene as carbon

  18. Evaluation of a low-cost ceramic micro-porous filter for elimination of common disease microorganisms

    Science.gov (United States)

    Simonis, Jean Jacques; Basson, Albertus Koetzee

    In this research project, the microbiological quality of the water processed by a low cost, newly developed micro-porous ceramic filter is evaluated. As 66% of the human body is made up of water, it is important to ensure the availability of clean, potable water that is free from pathogens. Even clean-looking water can still contain bacteria and other toxic impurities. Annually, millions of people contract severe illnesses from drinking water. One simple but effective way of making sure that water is of good quality is by making use of a household water filter. It is, however, of critical importance that such a low cost water filter is capable of removing suspended solids, pathogenic bacteria and other toxins from the drinking water. A low cost, micro-porous ceramic water filter with micron-sized pores was developed using the slip casting process. Naturally occurring water from two streams and a lake containing different species of bacteria was used in testing the ceramic filter’s effectiveness in eliminating bacteria. The filter proved to be effective in providing protection from bacteria and suspended solids found in natural water. This filtration process is suggested as a possible solution for the problem faced by more than 250 million people in Africa without provision of clean drinking water.

  19. Time-Dependent CO[subscript 2] Sorption Hysteresis in a One-Dimensional Microporous Octahedral Molecular Sieve

    Energy Technology Data Exchange (ETDEWEB)

    Espinal, Laura; Wong-Ng, Winnie; Kaduk, James A.; Allen, Andrew J.; Snyder, Chad R.; Chiu, Chun; Siderius, Daniel W.; Li, Lan; Cockayne, Eric; Espinal, Anais E.; Suib, Steven L. (IIT); (NIST); (Connecticut)

    2014-09-24

    The development of sorbents for next-generation CO{sub 2} mitigation technologies will require better understanding of CO{sub 2}/sorbent interactions. Among the sorbents under consideration are shape-selective microporous molecular sieves with hierarchical pore morphologies of reduced dimensionality. We have characterized the non-equilibrium CO{sub 2} sorption of OMS-2, a well-known one-dimensional microporous octahedral molecular sieve with manganese oxide framework. Remarkably, we find that the degree of CO{sub 2} sorption hysteresis increases when the gas/sorbent system is allowed to equilibrate for longer times at each pressure step. Density functional theory calculations indicate a 'gate-keeping' role of the cation in the tunnel, only allowing CO{sub 2} molecules to enter fully into the tunnel via a highly unstable transient state when CO{sub 2} loadings exceed 0.75 mmol/g. The energy barrier associated with the gate-keeping effect suggests an adsorption mechanism in which kinetic trapping of CO{sub 2} is responsible for the observed hysteretic behavior.

  20. The osteogenic capacity of biomimetic hierarchical micropore/nanorod-patterned Sr-HA coatings with different interrod spacings.

    Science.gov (United States)

    Zhou, Jianhong; Li, Bo; Han, Yong; Zhao, Lingzhou

    2016-07-01

    Advanced titanium based bone implant with fast established, rigid and stable osseointegration is stringently needed in clinic. Here the hierarchical micropore/nanorod-patterned strontium doped hydroxyapatite (Ca9Sr1(PO4)6(OH)2, Sr1-HA) coatings (MNRs) with different interrod spacings varying from about 300 to 33nm were developed. MNRs showed dramatically differential biological performance closely related to the interrod spacing. Compared to micropore/nanogranule-patterned Sr1-HA coating (MNG), MNRs with an interrod spacing of larger than 137nm resulted in inhibited in vitro mesenchymal stem cell functions and in vivo osseointegration, while those of smaller than 96nm gave rise to dramatically enhanced the biological effect, especially those of mean 67nm displayed the best effect. The differential biological effect of MNRs was related to their modulation on the focal adhesion mediated mechanotransduction. These results suggest that MNRs with a mean interrod spacing of 67nm may give rise to an advanced implant of improved clinical performance.

  1. Effects of textural and surface characteristics of microporous activated carbons on the methane adsorption capacity at high pressures

    Energy Technology Data Exchange (ETDEWEB)

    Bastos-Neto, M. [Grupo de Pesquisas em Separacoes por Adsorcao (GPSA), Departamento de Engenharia Quimica, Universidade Federal do Ceara, Campus Universitario do Pici, Bl 709 60455-760 Fortaleza, CE (Brazil); Canabrava, D.V. [Grupo de Pesquisas em Separacoes por Adsorcao (GPSA), Departamento de Engenharia Quimica, Universidade Federal do Ceara, Campus Universitario do Pici, Bl 709 60455-760 Fortaleza, CE (Brazil); Torres, A.E.B. [Grupo de Pesquisas em Separacoes por Adsorcao (GPSA), Departamento de Engenharia Quimica, Universidade Federal do Ceara, Campus Universitario do Pici, Bl 709 60455-760 Fortaleza, CE (Brazil); Rodriguez-Castellon, E. [Departamento de Quimica Inorganica, Cristalografia y Mineralogia (Unidad Asociada al ICP-CSIC), Facultad de Ciencias, Universidad de Malaga, 29071 Malaga (Spain); Jimenez-Lopez, A. [Departamento de Quimica Inorganica, Cristalografia y Mineralogia (Unidad Asociada al ICP-CSIC), Facultad de Ciencias, Universidad de Malaga, 29071 Malaga (Spain); Azevedo, D.C.S. [Grupo de Pesquisas em Separacoes por Adsorcao (GPSA), Departamento de Engenharia Quimica, Universidade Federal do Ceara, Campus Universitario do Pici, Bl 709 60455-760 Fortaleza, CE (Brazil)]. E-mail: diana@gpsa.ufc.br; Cavalcante, C.L. [Grupo de Pesquisas em Separacoes por Adsorcao (GPSA), Departamento de Engenharia Quimica, Universidade Federal do Ceara, Campus Universitario do Pici, Bl 709 60455-760 Fortaleza, CE (Brazil)

    2007-04-30

    The objective of this study is to relate textural and surface characteristics of selected microporous activated carbons to their methane storage capacity. In this work, a magnetic suspension balance (Rubotherm, Germany) was used to measure methane adsorption isotherms of several activated carbon samples. Textural characteristics were assessed by nitrogen adsorption on a regular surface area analyzer (Autosorb-MP, by Quantachrome, USA). N{sub 2} adsorption was analysed by conventional models (BET, DR, HK) and by Monte Carlo molecular simulations. Elemental and surface analyses were performed by X-ray photoelectronic spectroscopy (XPS) for the selected samples. A comparative analysis was then carried out with the purpose of defining some correlation among the variables under study. For the system under study, pore size distribution and micropore volume seem to be a determining factor as long as the solid surface is perfectly hydrophobic. It was concluded that the textural parameters per se do not unequivocally determine natural gas storage capacities. Surface chemistry and methane adsorption equilibria must be taken into account in the decision-making process of choosing an adsorbent for gas storage.

  2. Furfuralcohol Co-Polymerized Urea Formaldehyde Resin-derived N-Doped Microporous Carbon for CO2 Capture

    Science.gov (United States)

    Liu, Zhen; Yang, Yi; Du, Zhenyu; Xing, Wei; Komarneni, Sridhar; Zhang, Zhongdong; Gao, Xionghou; Yan, Zifeng

    2015-08-01

    Carbon-based adsorbent is considered to be one of the most promising adsorbents for CO2 capture form flue gases. In this study, a series of N-doped microporous carbon materials were synthesized from low cost and widely available urea formaldehyde resin co-polymerized with furfuralcohol. These N-doped microporous carbons showed tunable surface area in the range of 416-2273 m2 g-1 with narrow pore size distribution within less than 1 nm and a high density of the basic N functional groups (2.93-13.92 %). Compared with the carbon obtained from urea resin, the addition of furfuralcohol apparently changed the surface chemical composition and pore size distribution, especially ultramicropores as can be deduced from the X-ray photoelectron spectroscopy (XPS), Fourier transform infrared (FT-IR), and pore size distribution measurements and led to remarkable improvement on CO2 adsorption capacity. At 1 atm, N-doped carbons activated at 600 °C with KOH/UFFC weight ratio of 2 (UFFA-2-600) showed the highest CO2 uptake of 3.76 and 1.57 mmol g-1 at 25 and 75 °C, respectively.

  3. Improvement of the antifouling characteristics in a bioreactor of polypropylene microporous membrane by the adsorption of Tween 20

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    Surface modification by physical adsorption of Tween 20 was accomplished on polypropylene microporous membranes (PPMMs). Attenuated total reflection-Fourier transform infrared spectroscopy (ATR/FT-IR) and scanning electron microscope (SEM) were used to characterize the chemical and morphological changes on the membrane surfaces. Water contact angles and relative pure water fluxes were measured. The data showed that the hydrophilic performance for the modified membranes increased with the increase in the adsorption amount of Tween 20 onto the surface or into the pores of polypropylene microporous membranes. To test the antifouling property of the membranes by the adsorption of Tween 20 in a membrane bioreactor (MBR), filtration for active sludge was performed using synthetic wastewater. With the help of the data of water fluxes and the FE-SEM photos of the modified PPMMs before or after operating in a MBR for about 12 d, the PPMMs with monolayer adsorption of Tween 20 showed higher remained flux and stronger antifouling ability than unmodified membrane and other modification membranes studied.

  4. Gas/vapour separation using ultra-microporous metal–organic frameworks: insights into the structure/separation relationship

    KAUST Repository

    Adil, Karim

    2017-05-30

    The separation of related molecules with similar physical/chemical properties is of prime industrial importance and practically entails a substantial energy penalty, typically necessitating the operation of energy-demanding low temperature fractional distillation techniques. Certainly research efforts, in academia and industry alike, are ongoing with the main aim to develop advanced functional porous materials to be adopted as adsorbents for the effective and energy-efficient separation of various important commodities. Of special interest is the subclass of metal-organic frameworks (MOFs) with pore aperture sizes below 5-7 Å, namely ultra-microporous MOFs, which in contrast to conventional zeolites and activated carbons show great prospects for addressing key challenges in separations pertaining to energy and environmental sustainability, specifically materials for carbon capture and separation of olefin/paraffin, acetylene/ethylene, linear/branched alkanes, xenon/krypton, etc. In this tutorial review we discuss the latest developments in ultra-microporous MOF adsorbents and their use as separating agents via thermodynamics and/or kinetics and molecular sieving. Appreciably, we provide insights into the distinct microscopic mechanisms governing the resultant separation performances, and suggest a plausible correlation between the inherent structural features/topology of MOFs and the associated gas/vapour separation performance.

  5. Eliminating micro-porous layer from gas diffusion electrode for use in high temperature polymer electrolyte membrane fuel cell

    Science.gov (United States)

    Su, Huaneng; Xu, Qian; Chong, Junjie; Li, Huaming; Sita, Cordellia; Pasupathi, Sivakumar

    2017-02-01

    In this work, we report a simple strategy to improve the performance of high temperature polymer electrolyte membrane fuel cell (HT-PEMFC) by eliminating the micro-porous layer (MPL) from its gas diffusion electrodes (GDEs). Due to the absence of liquid water and the general use of high amount of catalyst, the MPL in a HT-PEMFC system works limitedly. Contrarily, the elimination of the MPL leads to an interlaced micropore/macropore composited structure in the catalyst layer (CL), which favors gas transport and catalyst utilization, resulting in a greatly improved single cell performance. At the normal working voltage (0.6 V), the current density of the GDE eliminated MPL reaches 0.29 A cm-2, and a maximum power density of 0.54 W cm-2 at 0.36 V is obtained, which are comparable to the best results yet reported for the HT-PEMFCs with similar Pt loading and operated using air. Furthermore, the MPL-free GDE maintains an excellent durability during a preliminary 1400 h HT-PEMFC operation, owing to its structure advantages, indicating the feasibility of this electrode for practical applications.

  6. Evaluation of a Cyclodextrin-silica Hybrid Microporous Composite for the Solid-phase Extraction of Polycyclic Aromatic Hydrocarbons.

    Science.gov (United States)

    Soler-Seguí, Salomé; Belenguer-Sapiña, Carolinakn-Aut-Sei; Amorós, Pedro; Mauri-Aucejo, Adela

    2016-01-01

    Solid-phase extraction (SPE) coupled with high-performance liquid chromatography (HPLC) with fluorescence detection were employed to determine trace polycyclic aromatic hydrocarbons in water samples. In this way, the use of cartridges containing cyclodextrin-silica hybrid microporous solid phases was proposed. The experimental results indicated that the method provided relative standard deviations of below 15% and detection limits recorded were 12, 1.2, 12, 38, 4, 6 and 4 ng L(-1) for benzo[b]fluoranthene, benzo[k]fluoranthene, benzo[g,h,i]perylene, indeno[1,2,3]pyrene, benzo[a]pyrene, dibenzo[a,h]anthracene and benzo[a]anthracene, respectively. Moreover, the method was successfully applied for the determination of these organic compounds in water samples, where they were found to be in the 7 to 580 ng L(-1) range. It can be concluded that the major advantages of cyclodextrin-silica hybrid microporous solid phases are that they reduce the consumption and the toxicity of the solvent and the time consumption of the sample treatment step.

  7. Graphene-wrapped sulfur/metal organic framework-derived microporous carbon composite for lithium sulfur batteries

    Directory of Open Access Journals (Sweden)

    Renjie Chen

    2014-12-01

    Full Text Available A three-dimensional hierarchical sandwich-type graphene sheet-sulfur/carbon (GS-S/CZIF8-D composite for use in a cathode for a lithium sulfur (Li-S battery has been prepared by an ultrasonic method. The microporous carbon host was prepared by a one-step pyrolysis of Zeolitic Imidazolate Framework-8 (ZIF-8, a typical zinc-containing metal organic framework (MOF, which offers a tunable porous structure into which electro-active sulfur can be diffused. The thin graphene sheet, wrapped around the sulfur/zeolitic imidazolate framework-8 derived carbon (S/CZIF8-D composite, has excellent electrical conductivity and mechanical flexibility, thus facilitating rapid electron transport and accommodating the changes in volume of the sulfur electrode. Compared with the S/CZIF8-D sample, Li-S batteries with the GS-S/CZIF8-D composite cathode showed enhanced capacity, improved electrochemical stability, and relatively high columbic efficiency by taking advantage of the synergistic effects of the microporous carbon from ZIF-8 and a highly interconnected graphene network. Our results demonstrate that a porous MOF-derived scaffold with a wrapped graphene conductive network structure is a potentially efficient design for a battery electrode that can meet the challenge arising from low conductivity and volume change.

  8. Graphene-wrapped sulfur/metal organic framework-derived microporous carbon composite for lithium sulfur batteries

    Science.gov (United States)

    Chen, Renjie; Zhao, Teng; Tian, Tian; Cao, Shuai; Coxon, Paul R.; Xi, Kai; Fairen-Jimenez, David; Vasant Kumar, R.; Cheetham, Anthony K.

    2014-12-01

    A three-dimensional hierarchical sandwich-type graphene sheet-sulfur/carbon (GS-S/CZIF8-D) composite for use in a cathode for a lithium sulfur (Li-S) battery has been prepared by an ultrasonic method. The microporous carbon host was prepared by a one-step pyrolysis of Zeolitic Imidazolate Framework-8 (ZIF-8), a typical zinc-containing metal organic framework (MOF), which offers a tunable porous structure into which electro-active sulfur can be diffused. The thin graphene sheet, wrapped around the sulfur/zeolitic imidazolate framework-8 derived carbon (S/CZIF8-D) composite, has excellent electrical conductivity and mechanical flexibility, thus facilitating rapid electron transport and accommodating the changes in volume of the sulfur electrode. Compared with the S/CZIF8-D sample, Li-S batteries with the GS-S/CZIF8-D composite cathode showed enhanced capacity, improved electrochemical stability, and relatively high columbic efficiency by taking advantage of the synergistic effects of the microporous carbon from ZIF-8 and a highly interconnected graphene network. Our results demonstrate that a porous MOF-derived scaffold with a wrapped graphene conductive network structure is a potentially efficient design for a battery electrode that can meet the challenge arising from low conductivity and volume change.

  9. Nitrogen-containing microporous conjugated polymers via carbazole-based oxidative coupling polymerization: preparation, porosity, and gas uptake.

    Science.gov (United States)

    Chen, Qi; Liu, De-Peng; Luo, Min; Feng, Li-Juan; Zhao, Yan-Chao; Han, Bao-Hang

    2014-01-29

    Facile preparation of microporous conjugated polycarbazoles via carbazole-based oxidative coupling polymerization is reported. The process to form the polymer network has cost-effective advantages such as using a cheap catalyst, mild reaction conditions, and requiring a single monomer. Because no other functional groups such as halo groups, boric acid, and alkyne are required for coupling polymerization, properties derived from monomers are likely to be fully retained and structures of final polymers are easier to characterize. A series of microporous conjugated polycarbazoles (CPOP-2-7) with permanent porosity are synthesized using versatile carbazolyl-bearing 2D and 3D conjugated core structures with non-planar rigid conformation as building units. The Brunauer-Emmett-Teller specific surface area values for these porous materials vary between 510 and 1430 m(2) g(-1) . The dominant pore sizes of the polymers based on the different building blocks are located between 0.59 and 0.66 nm. Gas (H2 and CO2 ) adsorption isotherms show that CPOP-7 exhibits the best uptake capacity for hydrogen (1.51 wt% at 1.0 bar and 77 K) and carbon dioxide (13.2 wt% at 1.0 bar and 273 K) among the obtained polymers. Furthermore, its high CH4 /N2 and CO2 /N2 adsorption selectivity gives polymer CPOP-7 potential application in gas separation.

  10. Preparation of Microporous Polypropylene/Titanium Dioxide Composite Membranes with Enhanced Electrolyte Uptake Capability via Melt Extruding and Stretching

    Directory of Open Access Journals (Sweden)

    Shan Wang

    2017-03-01

    Full Text Available In this work, a blending strategy based on compounding the hydrophilic titanium dioxide (TiO2 particles with the host polypropylene (PP pellets, followed by the common membrane manufacture process of melt extruding/annealing/stretching, was used to improve the polarity and thus electrolyte uptake capability of the PP-based microporous membranes. The influence of the TiO2 particles on the crystallinity and crystalline orientation of the PP matrix was studied using differential scanning calorimetry (DSC, X-ray diffraction (XRD, and infrared dichroic methods. The results showed that the TiO2 incorporation has little influence on the oriented lamellar structure of the PP-based composite films. Investigations of the deformation behavior indicated that both the lamellar separation and interfacial debonding occurred when the PP/TiO2 composite films were subjected to uniaxial tensile stress. The scanning electron microscopy (SEM observations verified that two forms of micropores were generated in the stretched PP/TiO2 composite membranes. Compared to the virgin PP membrane, the PP/TiO2 composite membranes especially at high TiO2 loadings showed significant improvements in terms of water vapor permeability, polarity, and electrolyte uptake capability. The electrolyte uptake of the PP/TiO2 composite membrane with 40 wt % TiO2 was 104%, which had almost doubled compared with that of the virgin PP membrane.

  11. A 2D Semiquinone Radical-Containing Microporous Magnet with Solvent-Induced Switching from Tc = 26 to 80 K.

    Science.gov (United States)

    Jeon, Ie-Rang; Negru, Bogdan; Van Duyne, Richard P; Harris, T David

    2015-12-23

    The incorporation of tetraoxolene radical bridging ligands into a microporous magnetic solid is demonstrated. Metalation of the redox-active bridging ligand 2,5-dichloro-3,6-dihydroxy-1,4-benzoquinone (LH2) with Fe(II) affords the solid (Me2NH2)2[Fe2L3]·2H2O·6DMF. Analysis of X-ray diffraction, Raman spectra, and Mössbauer spectra confirm the presence of Fe(III) centers with mixed-valence ligands of the form (L3)(8-) that result from a spontaneous electron transfer from Fe(II) to L(2-). Upon removal of DMF and H2O solvent molecules, the compound undergoes a slight structural distortion to give the desolvated phase (Me2NH2)2[Fe2L3], and a fit to N2 adsorption data of this activated compound gives a BET surface area of 885(105) m(2)/g. Dc magnetic susceptibility measurements reveal a spontaneous magnetization below 80 and 26 K for the solvated and the activated solids, respectively, with magnetic hysteresis up to 60 and 20 K. These results highlight the ability of redox-active tetraoxolene ligands to support the formation of a microporous magnet and provide the first example of a structurally characterized extended solid that contains tetraoxolene radical ligands.

  12. Inelastic neutron scattering study of binding of para-hydrogen in an ultra-microporous metal-organic framework

    Science.gov (United States)

    Yang, Sihai; Ramirez-Cuesta, Anibal J.; Schröder, Martin

    2014-01-01

    Metal-organic framework (MOF) materials show promise for H2 storage and it is widely predicted by computational modelling that MOFs incorporating ultra-micropores are optimal for H2 binding due to enhanced overlapping potentials. We report the investigation using inelastic neutron scattering of the interaction of H2 in an ultra-microporous MOF material showing low H2 uptake capacity. The study has revealed that adsorbed H2 at 5 K has a liquid recoil motion along the channel with very little interaction with the MOF host, consistent with the observed low uptake. The low H2 uptake is not due to incomplete activation or decomposition as the desolvated MOF shows CO2 uptake with a measured pore volume close to that of the single crystal pore volume. This study represents a unique example of surprisingly low H2 uptake within a MOF material, and complements the wide range of studies on systems showing higher uptake capacities and binding interactions.

  13. Glucose sensing in transdermal body fluid collected under continuous vacuum pressure via micropores in the stratum corneum.

    Science.gov (United States)

    Gebhart, Suzanne; Faupel, Mark; Fowler, Richard; Kapsner, Candis; Lincoln, Daniel; McGee, Valarie; Pasqua, John; Steed, Leigh; Wangsness, Michael; Xu, Fan; Vanstory, Madeleine

    2003-01-01

    Application of continuous vacuum pressure on skin perforated with tiny micropores created by a focused beam from a low-cost laser system can result in access to a clear, transdermal body fluid (TDF) for the continuous measurement of glucose in vivo. Two clinical studies were performed to assess the feasibility of this approach. In the first study, 56 diabetic subjects were porated on either the arm or abdomen, and glucose was measured in their TDF using a custom assay system contained in a patch that was affixed to the skin above the poration site. The continuous readings of glucose in TDF were compared with fingerstick blood measured every half-hour over a 2-day period, resulting in 1,167 paired data points that yielded a correlation of 0.8745 with 97.75% of the readings in the Clarke Error Grid A and B zones. In a second study, 187 diabetic and 65 nondiabetic subjects had glucose measurements from their TDF made using a commercially available glucose strip and meter. A total of 4,059 data pairs (discrete TDF and capillary blood) were collected over a 2-day period, resulting in a correlation of 0.946 with 99% of the readings in the Clarke Error Grid A and B zones. These studies indicate that TDF drawn through micropores in the stratum corneum of the skin potentially can provide a lesser invasive and continuous method of measuring glucose in diabetic individuals.

  14. Morphological, physical and chemical evaluation of the Vascugraft arterial prosthesis: comparison of a novel polyurethane device with other microporous structures.

    Science.gov (United States)

    Zhang, Z; King, M W; Guidoin, R; Therrien, M; Pezolet, M; Adnot, A; Ukpabi, P; Vantal, M H

    1994-06-01

    In this study the morphology, physical properties, surface chemical characteristics and microstructure of the Vascugraft arterial prosthesis have been investigated. This is a novel microporous polyurethane device, recently developed by the company Braun-Melsungen AG in Germany for use as a small calibre arterial substitute. This comparative study included two other synthetic grafts: the Mitrathane prosthesis, a hydrophilic prototype polyetherurethane urea graft with closed internal pores, and the commercially successful expanded polytetrafluoroethylene reinforced Goretex prosthesis with an open microporous structure. The Vascugraft prosthesis contains a network of fused microfibres of varying thickness and orientation which provide open and communicating pores similar in size to those in the Goretex material. In addition, they extend from one side of the graft wall to the other. As well as having superior longitudinal and radial compliance to the reinforced Goretex device, the Vascugraft prosthesis has more than adequate bursting and suture retention strengths. Through the use of contact angle measurements, electron spectroscopy for chemical analysis, Fourier transform infrared spectroscopy, differential scanning calorimetry and molecular weight analysis by size exclusion chromatography, the surface of the Vascugraft prosthesis has been shown to be uniquely hydrophobic, as well as containing carbonate groups within an aliphatic polyesterurethane polymer. In addition, variations in micro-phase separation structure of hard and soft segment domains between different sizes and batches of product are marginal. Because of the interesting physical and chemical properties, it is recommended that in vitro biocompatibility and biostability studies be undertaken prior to using the prosthesis in animal or clinical trials.

  15. Highly selective sieving of small gas molecules by using an ultra-microporous metal–organic framework membrane

    KAUST Repository

    Kang, Zixi

    2014-09-12

    © 2014 The Royal Society of Chemistry. Two tailor-made microporous metal-organic framework (MOF) membranes were successfully fabricated on nickel screens by secondary growth. The effect of pore structures on gas separation was examined by means of single and binary gas permeation tests. The MOF JUC-150 membrane with its ultra-micropores showed marked preferential permeance to H2 relative to other gas molecules. The selectivity factors of this membrane were 26.3, 17.1 and 38.7 for H2/CH4, H2/N2 and H2/CO2, respectively, at room temperature. To the best of our knowledge, these values represent unprecedentedly high separation selectivity among those for all MOF membranes reported to date. The JUC-150 membrane also shows high thermal stability and outstanding separation performance at a high temperature of 200 °C. The separation performance of these membranes persists even after more than 1 year exposure to air. The superiority of the tailored pore size, high selectivity for H2 over other gases, significant stability and recyclability make these materials potential candidates for industrial H2 recycling applications.

  16. Graphene-wrapped sulfur/metal organic framework-derived microporous carbon composite for lithium sulfur batteries

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Renjie, E-mail: kx210@cam.ac.uk, E-mail: chenrj@bit.edu.cn; Zhao, Teng [Beijing Key Laboratory of Environmental Science and Engineering, School of Chemical Engineering and Environment, Beijing Institute of Technology, Beijing 100081 (China); Department of Materials Science and Metallurgy, University of Cambridge, Cambridge CB3 0FS (United Kingdom); Tian, Tian; Fairen-Jimenez, David [Department of Chemical Engineering and Biotechnology, University of Cambridge, Pembroke Street, Cambridge CB2 3RA (United Kingdom); Cao, Shuai; Coxon, Paul R.; Xi, Kai, E-mail: kx210@cam.ac.uk, E-mail: chenrj@bit.edu.cn; Vasant Kumar, R.; Cheetham, Anthony K. [Department of Materials Science and Metallurgy, University of Cambridge, Cambridge CB3 0FS (United Kingdom)

    2014-12-01

    A three-dimensional hierarchical sandwich-type graphene sheet-sulfur/carbon (GS-S/C{sub ZIF8-D}) composite for use in a cathode for a lithium sulfur (Li-S) battery has been prepared by an ultrasonic method. The microporous carbon host was prepared by a one-step pyrolysis of Zeolitic Imidazolate Framework-8 (ZIF-8), a typical zinc-containing metal organic framework (MOF), which offers a tunable porous structure into which electro-active sulfur can be diffused. The thin graphene sheet, wrapped around the sulfur/zeolitic imidazolate framework-8 derived carbon (S/C{sub ZIF8-D}) composite, has excellent electrical conductivity and mechanical flexibility, thus facilitating rapid electron transport and accommodating the changes in volume of the sulfur electrode. Compared with the S/C{sub ZIF8-D} sample, Li-S batteries with the GS-S/C{sub ZIF8-D} composite cathode showed enhanced capacity, improved electrochemical stability, and relatively high columbic efficiency by taking advantage of the synergistic effects of the microporous carbon from ZIF-8 and a highly interconnected graphene network. Our results demonstrate that a porous MOF-derived scaffold with a wrapped graphene conductive network structure is a potentially efficient design for a battery electrode that can meet the challenge arising from low conductivity and volume change.

  17. High-performance carbon molecular sieve membranes for ethylene/ethane separation derived from an intrinsically microporous polyimide

    KAUST Repository

    Salinas, Octavio

    2015-11-18

    An intrinsically microporous polymer with hydroxyl functionalities, PIM-6FDA-OH, was used as a precursor for various types of carbon molecular sieve (CMS) membranes for ethylene/ethane separation. The pristine polyimide films were heated under controlled N2 atmosphere at different stages from 500 to 800 °C. All CMS samples carbonized above 600 °C surpassed the polymeric ethylene/ethane upper bound. Pure-gas selectivity reached 17.5 for the CMS carbonized at 800 °C with an ethylene permeability of about 10 Barrer at 2 bar and 35 °C, becoming the most selective CMS for ethylene/ethane separation reported to date. As expected, gravimetric sorption experiments showed that all CMS membranes had ethylene/ethane solubility selectivities close to one. The permselectivity increased with increasing pyrolysis temperature due to densification of the micropores in the CMS membranes, leading to enhanced diffusivity selectivity. Mixed-gas tests with a binary 50:50 v/v ethylene/ethane feed showed a decrease in selectivity from 14 to 8.3 as the total feed pressure was increased from 4 to 20 bar. The selectivity drop under mixed-gas conditions was attributed to non-ideal effects: (i) Competitive sorption that reduced the permeability of ethylene and (ii) dilation of the CMS that resulted in an increase in the ethane permeability.

  18. Carbon Dioxide Removal from Flue Gas Using Microporous Metal Organic Frameworks

    Energy Technology Data Exchange (ETDEWEB)

    Lesch, David A

    2010-06-30

    UOP LLC, a Honeywell Company, in collaboration with Professor Douglas LeVan at Vanderbilt University (VU), Professor Adam Matzger at the University of Michigan (UM), Professor Randall Snurr at Northwestern University (NU), and Professor Stefano Brandani at the University of Edinburgh (UE), supported by Honeywell's Specialty Materials business unit and the Electric Power Research Institute (EPRI), have completed a three-year project to develop novel microporous metal organic frameworks (MOFs) and an associated vacuum-pressure swing adsorption (vPSA) process for the removal of CO{sub 2} from coal-fired power plant flue gas. The project leveraged the team's complementary capabilities: UOP's experience in materials development and manufacturing, adsorption process design and process commercialization; LeVan and Brandani's expertise in high-quality adsorption measurements; Matzger's experience in syntheis of MOFs and the organic components associated with MOFs; Snurr's expertise in molecular and other modeling; Honeywell's expertise in the manufacture of organic chemicals; and, EPRI's knowledge of power-generation technology and markets. The project was successful in that a selective CO{sub 2} adsorbent with good thermal stability and reasonable contaminant tolerance was discovered, and a low cost process for flue gas CO{sub 2} capture process ready to be evaluated further at the pilot scale was proposed. The team made significant progress toward the current DOE post-combustion research targets, as defined in a recent FOA issued by NETL: 90% CO{sub 2} removal with no more than a 35% increase in COE. The team discovered that favorable CO{sub 2} adsorption at more realistic flue gas conditions is dominated by one particular MOF structure type, M/DOBDC, where M designates Zn, Co, Ni, or Mg and DOBDC refers to the form of the organic linker in the resultant MOF structure, dioxybenzenedicarboxylate. The structure of the M/DOBDC MOFs

  19. Thermal Tuning of Ethylene/Ethane Selective Cavities of Intrinsically Microporous Polymers

    KAUST Repository

    Salinas, Octavio

    2016-06-21

    Ethylene is the most important organic molecule with regard to production volume. Therefore, the energy spent in its separation processes, based on old-fashioned distillation, takes approx. 33% of total operating costs. Membranes do not require significant thermal energy input; therefore, membrane processes may separate hydrocarbons cheaply and just as reliably as distillation columns. Olefin/paraffin separations are the future targets of commercial membrane applications, provided high-performing materials become available at reasonable prices. This thesis addresses the development of advanced carbon molecular sieve (CMS) membranes derived from intrinsically microporous polymers (PIMs). Chronologically, Chapter 4 of this work reports the evaluation of PIMs as potential ethylene/ethane selective materials, while Chapters 5 to 7 propose PIMs as carbonization precursors. The gravimetric sorption studies conducted in this work regarding both the polymers and their heated-derivatives revealed that this separation is entirely controlled by diffusion differences. The pristine polymers examined in this study presented BET surface areas from 80 to 720 m2g-1. Furthermore, the effect of using bromine-substituted PIM-polyimides elucidated a boost in ethylene permeability, but with a significant drop in selectivity. The hydroxyl functionalization of PIM-polyimides was confirmed as a valuable strategy to increase selectivity. Functionalized PMDA-HSBF is the most selective polyimide of intrinsic microporosity known to date (= 5.1) due to its hydrogen-bonded matrix. In spite of their novelty, pristine PIMs based on the spirobisindane moiety were not tight enough to distinguish between the 0.2 Å difference in diameter of the ethylene/ethane molecules. Therefore, they did not surpass the upper bound limit performance of known polymeric membranes. Nevertheless, the carbons derived from these polymers were excellent ethylene/ethane sieves by virtue of their narrow and tight

  20. Microporous hollow fibre membrane modules as gas-liquid contactors. Part 1: Physical mass transfer processes. A specific application: mass transfer in highly viscous liquids

    NARCIS (Netherlands)

    Kreulen, H.; Versteeg, G.F.; Smolders, C.A.; Swaaij, van W.P.M.

    1993-01-01

    Gas-liquid mass transfer has been studied in a membrane module with non-wetted microporous fibres in the laminar flow regime. This new type of gas/liquid contactor can be operated stabily over a large range of gas and liquid flows because gas and liquid phase do not influence each other directly. Th

  1. A new microporous carbon material synthesized via thermolysis of a porous aromatic framework embedded with an extra carbon source for low-pressure CO2 uptake.

    Science.gov (United States)

    Zhang, Yiming; Li, Baiyan; Williams, Kia; Gao, Wen-Yang; Ma, Shengqian

    2013-11-11

    Pre-introducing an extra carbon source into the porous aromatic framework of PAF-1 followed by thermolysis affords a new microporous carbon material, which demonstrates a CO2 uptake capacity of 93 cm(3) g(-1) (equivalent to 4.1 mmol g(-1) or 18.2 wt%) at 295 K and 1 bar.

  2. Controlled long-term release of small peptide hormones using a new microporous polypropylene polymer: its application for vasopressin in the Brattleboro rat and potential perinatal use

    Energy Technology Data Exchange (ETDEWEB)

    Kruisbrink, J.; Boer, G.J.

    1984-12-01

    Based on drug release by microporous hollow fibers and the recent introduction of microporous polymers, a new technique was developed for controlled delivery of peptides. Small-diameter microporous polypropylene tubing, lumen-loaded with microgram quantities of vasopressin, and coated with collodion, releases vasopressin after in vitro immersion slowly (1-100 ng/d) and constantly for months. The mechanism of pseudo-zero-order delivery is based on high adsorption of vasopressin, keeping the void volume concentration of dissolved vasopressin constant, which is consequently a constant driving force of outward diffusion. The collodion coating prevents the entry of proteinaceous compounds which would result in rapid desorption of vasopressin. The present delivery module provides a lasting release for other peptides as well (lysine-vasopressin, oxytocin, alpha-melanocyte-stimulating hormone and, to a lesser extent, Met-enkephalin). The microporous polymer-collodion device is biocompatible and, loaded with vasopressin, successfully alleviates the diabetes insipidus of Brattleboro rats deficient for vasopressin. Subcutaneous implantation normalized diuresis for a period of 60 d and constant urine vasopressin excretion is observed. When the commercially available osmotic minipump is too large for implantation, the small size of the present controlled-delivery system allows peptide treatment of young and immature laboratory rats, even if located in utero.

  3. A rod-packing microporous hydrogen-bonded organic framework for highly selective separation of C2H2/CO2at room temperature

    KAUST Repository

    Li, Peng

    2014-11-13

    Self-assembly of a trigonal building subunit with diaminotriazines (DAT) functional groups leads to a unique rod-packing 3D microporous hydrogen-bonded organic framework (HOF-3). This material shows permanent porosity and demonstrates highly selective separation of C2H2/CO2 at ambient temperature and pressure.

  4. A microporous Cu-MOF with optimized open metal sites and pore spaces for high gas storage and active chemical fixation of CO2.

    Science.gov (United States)

    Gao, Chao-Ying; Tian, Hong-Rui; Ai, Jing; Li, Lei-Jiao; Dang, Song; Lan, Ya-Qian; Sun, Zhong-Ming

    2016-09-25

    A microporous Cu-MOF with optimized open metal sites and pore space was constructed based on a designed bent ligand; it exhibits high-capacity multiple gas storage under atmospheric pressure and efficient catalytic activity for chemical fixation of CO2 under mild conditions.

  5. Highly Sensitive, Flexible, and Wearable Pressure Sensor Based on a Giant Piezocapacitive Effect of Three-Dimensional Microporous Elastomeric Dielectric Layer.

    Science.gov (United States)

    Kwon, Donguk; Lee, Tae-Ik; Shim, Jongmin; Ryu, Seunghwa; Kim, Min Seong; Kim, Seunghwan; Kim, Taek-Soo; Park, Inkyu

    2016-07-06

    We report a flexible and wearable pressure sensor based on the giant piezocapacitive effect of a three-dimensional (3-D) microporous dielectric elastomer, which is capable of highly sensitive and stable pressure sensing over a large tactile pressure range. Due to the presence of micropores within the elastomeric dielectric layer, our piezocapacitive pressure sensor is highly deformable by even very small amounts of pressure, leading to a dramatic increase in its sensitivity. Moreover, the gradual closure of micropores under compression increases the effective dielectric constant, thereby further enhancing the sensitivity of the sensor. The 3-D microporous dielectric layer with serially stacked springs of elastomer bridges can cover a much wider pressure range than those of previously reported micro-/nanostructured sensing materials. We also investigate the applicability of our sensor to wearable pressure-sensing devices as an electronic pressure-sensing skin in robotic fingers as well as a bandage-type pressure-sensing device for pulse monitoring at the human wrist. Finally, we demonstrate a pressure sensor array pad for the recognition of spatially distributed pressure information on a plane. Our sensor, with its excellent pressure-sensing performance, marks the realization of a true tactile pressure sensor presenting highly sensitive responses to the entire tactile pressure range, from ultralow-force detection to high weights generated by human activity.

  6. Molecular dynamics investigation of separation of hydrogen sulfide from acidic gas mixtures inside metal-doped graphite micropores.

    Science.gov (United States)

    Huang, Pei-Hsing

    2015-09-21

    The separation of poisonous compounds from various process fluids has long been highly intractable, motivating the present study on the dynamic separation of H2S in acidic-gas-mixture-filled micropores. The molecular dynamics approach, coupled with the isothermal-isochoric ensemble, was used to model the molecular interactions and adsorption of H2S/CO2/CO/H2O mixtures inside metal-doped graphite slits. Due to the difference in the adsorption characteristics between the two distinct adsorbent materials, the metal dopant in the graphitic micropores leads to competitive adsorption, i.e. the Au and graphite walls compete to capture free adsorbates. The effects of competitive adsorption, coupled with changes in the gas temperature, concentration, constituent ratio and slit width on the constituent separation of mixtures were systematically studied. The molecule-wall binding energies calculated in this work (those of H2S, H2O and CO on Au walls and those of H2O, CO and CO2 on graphite walls) show good agreement with those obtained using density functional theory (DFT) and experimental results. The z-directional self-diffusivities (Dz) for adsorbates inside the slit ranged from 10(-9) to 10(-7) m(2) s(-1) as the temperature was increased from 10 to 500 K. The values are comparable with those for a typical microporous fluid (10(-8)-10(-9) m(2) s(-1) in a condensed phase and 10(-6)-10(-7) m(2) s(-1) in the gaseous state). The formation of H-bonding networks and hydrates of H2S is disadvantageous for the separation of mixtures. The results indicate that H2S can be efficiently separated from acidic gas mixtures onto the Au(111) surface by (i) reducing the mole fraction of H2S and H2O in the mixtures, (ii) raising the gas temperature to the high temperature limit (≥400 K), and (iii) lowering the slit width to below the threshold dimension (≤23.26 Å).

  7. 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.

  8. Microporous metal-organic framework with dual functionalities for highly efficient removal of acetylene from ethylene/acetylene mixtures

    Science.gov (United States)

    Hu, Tong-Liang; Wang, Hailong; Li, Bin; Krishna, Rajamani; Wu, Hui; Zhou, Wei; Zhao, Yunfeng; Han, Yu; Wang, Xue; Zhu, Weidong; Yao, Zizhu; Xiang, Shengchang; Chen, Banglin

    2015-06-01

    The removal of acetylene from ethylene/acetylene mixtures containing 1% acetylene is a technologically very important, but highly challenging task. Current removal approaches include the partial hydrogenation over a noble metal catalyst and the solvent extraction of cracked olefins, both of which are cost and energy consumptive. Here we report a microporous metal-organic framework in which the suitable pore/cage spaces preferentially take up much more acetylene than ethylene while the functional amine groups on the pore/cage surfaces further enforce their interactions with acetylene molecules, leading to its superior performance for this separation. The single X-ray diffraction studies, temperature dependent gas sorption isotherms, simulated and experimental column breakthrough curves and molecular simulation studies collaboratively support the claim, underlying the potential of this material for the industrial usage of the removal of acetylene from ethylene/acetylene mixtures containing 1% acetylene at room temperature through the cost- and energy-efficient adsorption separation process.

  9. DNA damage induced by bare and loaded microporous coordination polymers from their ground and electronic excited states.

    Science.gov (United States)

    Yañuk, Juan G; Alomar, María L; Gonzalez, M Micaela; Simon, Francisco; Erra-Balsells, Rosa; Rafti, Matías; Cabrerizo, Franco M

    2015-05-21

    We report on interactions of cell free double-stranded DNA (dsDNA) with a selected subgroup of Microporous Coordination Polymers (MCPs). In particular, we have studied the influence of different metal ion constituents and chemically modified linkers using a set of five benzene carboxylate-based MCPs. Our results suggest that the DNA moiety can be structurally modified in two different ways: by direct MCPs-dsDNA interaction and/or through photosensitized processes. The extent of the observed damage was found to be strongly dependent on the charge density of the material. The potential use of the MCPs tested as inert carriers of photosensitizers was demonstrated by analyzing the interaction between dsDNA and harmine-loaded Cr-based materials, both in the absence of light and upon UVA irradiation.

  10. Quantum dynamics of adsorbed H2 in the microporous framework MOF-5 analyzed using diffuse reflectance infrared spectroscopy

    Science.gov (United States)

    Fitzgerald, S. A.; Allen, K.; Landerman, P.; Hopkins, J.; Matters, J.; Myers, R.; Rowsell, J. L. C.

    2008-06-01

    Diffuse reflectance infrared spectroscopy is used to measure the quantum dynamics of molecular hydrogen adsorbed in the microporous material MOF-5. Low-temperature spectra reveal at least three distinct binding sites. The induced redshifts in the vibrational mode frequencies allow the estimation of site-specific binding energies ranging from 2.5 to 4 kJ/mol. Splittings in the rovibrational sidebands are consistent with the existing theories and indicate that H2 is relatively freely rotating even at temperatures as low as 10 K. Ortho to para conversion of the adsorbed H2 is observed to occur over the course of several hours. A translational sideband of 84cm-1 arises from the center-of-mass motion of H2 at the primary adsorption site and indicates that the zero-point energy is a substantial fraction of the binding energy of this site.

  11. Super-microporous solid base MgO-ZrO2 composite and their application in biodiesel production

    Science.gov (United States)

    Su, Jiaojiao; Li, Yongfeng; Wang, Huigang; Yan, Xiaoliang; Pan, Dahai; Fan, Binbin; Li, Ruifeng

    2016-10-01

    The super-microporous microcrystalline MgO-ZrO2 nanomaterials (pore size 1-2 nm) was prepared successfully via a facile one-pot evaporation-induced self-assembly (EISA) method and employed in the transesterification of soybean oil and methanol. X-ray diffraction, transmission electron microscope, temperature programmed desorption of CO2, and N2 adsorption porosimetry were employed to characterize the nanocomposites. Nitrogen sorption isotherms revealed that these materials had large surface areas of more than 200 m2/g. Moreover, the sample with a Mg/Zr molar ratio of 0.5 and calcined at 400 °C showed high biodiesel yield (around 99% at 150 °C).

  12. Microporous metal–organic framework with dual functionalities for highly efficient removal of acetylene from ethylene/acetylene mixtures

    KAUST Repository

    Hu, Tong-Liang

    2015-06-04

    The removal of acetylene from ethylene/acetylene mixtures containing 1% acetylene is a technologically very important, but highly challenging task. Current removal approaches include the partial hydrogenation over a noble metal catalyst and the solvent extraction of cracked olefins, both of which are cost and energy consumptive. Here we report a microporous metal–organic framework in which the suitable pore/cage spaces preferentially take up much more acetylene than ethylene while the functional amine groups on the pore/cage surfaces further enforce their interactions with acetylene molecules, leading to its superior performance for this separation. The single X-ray diffraction studies, temperature dependent gas sorption isotherms, simulated and experimental column breakthrough curves and molecular simulation studies collaboratively support the claim, underlying the potential of this material for the industrial usage of the removal of acetylene from ethylene/acetylene mixtures containing 1% acetylene at room temperature through the cost- and energy-efficient adsorption separation process.

  13. 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.

  14. Physicochemical and electrochemical characterization of battery separator prepared by radiation induced grafting of acrylic acid onto microporous polypropylene membranes

    Directory of Open Access Journals (Sweden)

    2009-05-01

    Full Text Available Mutual radiation grafting technique was used to graft acrylic acid on micrometer thick micro-porous polypropylene membrane using high-energy gamma radiation. Grafting could not be achieved in aqueous acrylic acid solution. The presence of Mohr’s salt effectively retarded the homopolymerization of acrylic acid but did not lead to grafting enhancement. Mohr’s salt in presence of acids was found to be effective in enhancing the grafting yield. Contact angle measurement studies of the grafted and radiation treated polypropylene showed that initial grafting as well as radiation treatment of poly(propylene in aqueous medium and in presence of Mohr’s salt enhances its affinity towards the grafting solution. The enhancement in the polar component of surface energy of treated polypropylene membrane is the primary cause of grafting enhancement. The membranes grafted to an extent of ~20% were found to perform comparably with the battery separator presently being used by battery industry.

  15. Fabrication of a carbon nanofiber sheet as a micro-porous layer for proton exchange membrane fuel cells

    Energy Technology Data Exchange (ETDEWEB)

    Duan, Qiongjuan; Wang, Jiong; Lu, Yonggen [College of Material Science and Engineering, Donghua University, Shanghai 201620 (China); Wang, Biao; Wang, Huaping [State Key Laboratory for Modification of Chemical Fibers and Polymer Materials, Donghua University, Shanghai 201620 (China); College of Material Science and Engineering, Donghua University, Shanghai 201620 (China)

    2010-12-15

    A carbon nanofiber sheet (CNFS) has been prepared by electrospinning, stabilisation and subsequent carbonisation processes. Imaging with scanning electron microscope (SEM) indicates that the CNFS is formed by nonwoven nanofibers with diameters between 400 and 700 nm. The CNFS, with its three-dimensional pores, shows excellent electrical conductivity and hydrophobicity. In addition, it is found that the CNFS can be successfully applied as a micro-porous layer (MPL) in the cathode gas diffusion layer (GDL) of a proton exchange membrane fuel cell (PEMFC). The GDL with the CNFS as a MPL has higher gas permeability than a conventional GDL. Moreover, the resultant cathode GDL exhibits excellent fuel cell performance with a higher peak power density than that of a cathode GDL fabricated with a conventional MPL under the same test condition. (author)

  16. Cobalt Ferrite Bearing Nitrogen-Doped Reduced Graphene Oxide Layers Spatially Separated with Microporous Carbon as Efficient Oxygen Reduction Electrocatalyst.

    Science.gov (United States)

    Kashyap, Varchaswal; Singh, Santosh K; Kurungot, Sreekumar

    2016-08-17

    The present work discloses how high-quality dispersion of fine particles of cobalt ferrite (CF) could be attained on nitrogen-doped reduced graphene oxide (CF/N-rGO) and how this material in association with a microporous carbon phase could deliver significantly enhanced activity toward electrochemical oxygen reduction reaction (ORR). Our study indicates that the microporous carbon phase plays a critical role in spatially separating the layers of CF/N-rGO and in creating a favorable atmosphere to ensure the seamless distribution of the reactants to the active sites located on CF/N-rGO. In terms of the ORR current density, the heat-treated hybrid catalyst at 150 °C (CF/N-rGO-150) is found to be clearly outperforming (7.4 ± 0.5 mA/cm(2)) the state-of-the-art 20 wt % Pt-supported carbon catalyst (PtC) (5.4 ± 0.5 mA/cm(2)). The mass activity and stability of CF-N-rGO-150 are distinctly superior to PtC even after 5000 electrochemical cycles. As a realistic system level exploration of the catalyst, testing of a primary zinc-air battery could be demonstrated using CF/N-rGO-150 as the cathode catalyst. The battery is giving a galvanostatic discharge time of 15 h at a discharge current density of 20 mA/cm(2) and a specific capacity of ∼630 mAh g(-1) in 6 M KOH by using a Zn foil as the anode. Distinctly, the battery performance of this system is found to be superior to that of PtC in less concentrated KOH solution as the electrolyte.

  17. A Highly Stable Microporous Covalent Imine Network Adsorbent for Natural Gas Upgrading and Flue Gas CO2 Capture

    KAUST Repository

    Das, Swapan Kumar

    2016-06-06

    The feasible capture and separation of CO2 and N2 from CH4 is an important task for natural gas upgrading and the control of greenhouse gas emissions. Here, we studied the microporous covalent imine networks (CIN) material prepared through Schiff base condensation and exhibited superior chemical robustness under both acidic and basic conditions and high thermal stability. The material possesses a relatively uniform nanoparticle size of approximately 70 to 100 nm. This network featured permanent porosity with a high surface area (722 m2g-1) and micropores. A single-component gas adsorption study showed enhanced CO2 and CH4 uptakes of 3.32 mmol/g and 1.14 mmol/g, respectively, at 273 K and 1 bar, coupled with high separation selectivities for CO2/CH4, CH4/N2, and CO2/N2 of 23, 11.8 and 211, respectively. The enriched Lewis basicity in the porous skeletons favours the interaction of quadrupolar CO2 and polarizable CH4, resulting in enhanced CH4 and CO2 uptake and high CH4/N2, CO2/CH4 and CO2/N2 selectivities. Breakthrough experiments showed high CO2/CH4, CH4/N2 and CO2/N2 selectivities of 7.29, 40 and 125, respectively, at 298 K and 1 bar. High heats of adsorption for CH4 and CO2 (QstCH4; 32.61 kJ mol-1 and QstCO2; 42.42 kJ mol-1) provide the ultimate validation for the high selectivity. To the best of our knowledge, such a versatile adsorbent material that displays both enhanced uptake and selectivity for a variety of binary gas mixtures, including CO2/ CH4, CO2/N2 and CH4/N2, has not been extensively explored.

  18. Electrochemical ion transfer across liquid/liquid interfaces confined within solid-state micropore arrays--simulations and experiments.

    Science.gov (United States)

    Strutwolf, Jörg; Scanlon, Micheál D; Arrigan, Damien W M

    2009-01-01

    Miniaturised liquid/liquid interfaces provide benefits for bioanalytical detection with electrochemical methods. In this work, microporous silicon membranes which can be used for interface miniaturisation were characterized by simulations and experiments. The microporous membranes possessed hexagonal arrays of pores with radii between 10 and 25 microm, a pore depth of 100 microm and pore centre-to-centre separations between 99 and 986 microm. Cyclic voltammetry was used to monitor ion transfer across arrays of micro-interfaces between two immiscible electrolyte solutions (microITIES) formed at these membranes, with the organic phase present as an organogel. The results were compared to computational simulations taking into account mass transport by diffusion and encompassing diffusion to recessed interfaces and overlapped diffusion zones. The simulation and experimental data were both consistent with the situation where the location of the liquid/liquid (l/l) interface was on the aqueous side of the silicon membrane and the pores were filled with the organic phase. While the current for the forward potential scan (transfer of the ion from the aqueous phase to the organic phase) was strongly dependent on the location of the l/l interface, the current peak during the reverse scan (transfer of the ion from the organic phase to the aqueous phase) was influenced by the ratio of the transferring ion's diffusion coefficients in both phases. The diffusion coefficient of the transferring ion in the gelified organic phase was ca. nine times smaller than in the aqueous phase. Asymmetric cyclic voltammogram shapes were caused by the combined effect of non-symmetrical diffusion (spherical and linear) and by the inequality of the diffusion coefficient in both phases. Overlapping diffusion zones were responsible for the observation of current peaks instead of steady-state currents during the forward scan. The characterisation of the diffusion behaviour is an important requirement

  19. [Study on the preparation and properties of novel silica microporous antireflective coating by sol-gel process].

    Science.gov (United States)

    Shang, Meng-Ying; Cao, Lin-Hong; Liu, Miao; Luo, Xuan; Ren, Hong-Bo; Ye, Xin; Tang, Yong-Jian; Jiang, Xiao-Dong

    2013-04-01

    Silica sol was prepared by acid catalyzed sol-gel process using tetraethylorthosilicate (TEOS) as precursor and dimethyldietoxysilane (DDS) as pore-forming agent. A novel kind of monolayer microporous silica anti-reflective (AR) coating was obtained on K9 glass substrate by dip-coating technique and then heat treated at 500 degrees C. The effects of different DDS/TEOS molar ratios on refractive index, transmittance and hardness were investigated. A positive correlation was found between the transmittance and the DDS/TEOS molar ratio due to the increasing porosity. The maximum transmittance can reach 99.7% with the molar ratio of DDS/TEOS rising to 1 : 1. Meanwhile, the refractive index was found quite close to the ideal value 1.22. Nevertheless, higher molar ratio will lead to a bad film-forming property. On the other hand, the hardness of the coatings decreased with the DDS increasing but still remained more than 2 h when the transmittance reached highest. Besides, these coatings exhibit a well abrasion-resistance and excellent adhesivity. The maximum transmittance was only dropped by 0.071% and 0.112% after abrasion for 500 and 1 000 times respectively. Accelerated corrosion tests indicated that the transmittance of traditional coatings rapidly fell down to the substrate level (-92%) after immersion for 5 min, while the transmittance of our novel coating almost linearly decreased and was kept 93.2% after 56 min. In other words, the environment-resistance of our novel silica AR coating is ten times higher than that of traditional ones. The promotions of the coating performances benefit from its micropore structure (-0. 4 nm) with which water molecule can be effectively prevented. With its high transmittance, good mechanical properties and high environment-resistance, this kind of novel coating has a potential application in the field of solar glass modification to improve its anti-reflective properties.

  20. Fischer-Tropsch synthesis over MOF-supported cobalt catalysts (Co@MIL-53(Al)).

    Science.gov (United States)

    Isaeva, V I; Eliseev, O L; Kazantsev, R V; Chernyshev, V V; Davydov, P E; Saifutdinov, B R; Lapidus, A L; Kustov, L M

    2016-07-26

    Novel nanohybrid materials were prepared by immobilizing Co nanoparticles on a microporous framework MIL-53(Al) as a porous host matrix. The synthesized cobalt-containing materials were characterized by XRD, STEM, and oxygen titration. The catalytic performance of Co@MIL-53(Al) nanohybrids was examined in Fischer-Tropsch synthesis (FTS) for the first time. A higher selectivity to C5+ hydrocarbons and lower selectivity to methane for Co@MIL-53(Al) as compared to conventional Co/Al2O3 were observed.

  1. Centimetre-scale micropore alignment in oriented polycrystalline metal-organic framework films via heteroepitaxial growth

    Science.gov (United States)

    Falcaro, Paolo; Okada, Kenji; Hara, Takaaki; Ikigaki, Ken; Tokudome, Yasuaki; Thornton, Aaron W.; Hill, Anita J.; Williams, Timothy; Doonan, Christian; Takahashi, Masahide

    2016-12-01

    The fabrication of oriented, crystalline films of metal-organic frameworks (MOFs) is a critical step toward their application to advanced technologies such as optics, microelectronics, microfluidics and sensing. However, the direct synthesis of MOF films with controlled crystalline orientation remains a significant challenge. Here we report a one-step approach, carried out under mild conditions, that exploits heteroepitaxial growth for the rapid fabrication of oriented polycrystalline MOF films on the centimetre scale. Our methodology employs crystalline copper hydroxide as a substrate and yields MOF films with oriented pore channels on scales that primarily depend on the dimensions of the substrate. To demonstrate that an anisotropic crystalline morphology can translate to a functional property, we assembled a centimetre-scale MOF film in the presence of a dye and showed that the optical response could be switched `ON’ or `OFF’ by simply rotating the film.

  2. Centimetre-scale micropore alignment in oriented polycrystalline metal-organic framework films via heteroepitaxial growth

    Science.gov (United States)

    Falcaro, Paolo; Okada, Kenji; Hara, Takaaki; Ikigaki, Ken; Tokudome, Yasuaki; Thornton, Aaron W.; Hill, Anita J.; Williams, Timothy; Doonan, Christian; Takahashi, Masahide

    2017-03-01

    The fabrication of oriented, crystalline films of metal-organic frameworks (MOFs) is a critical step toward their application to advanced technologies such as optics, microelectronics, microfluidics and sensing. However, the direct synthesis of MOF films with controlled crystalline orientation remains a significant challenge. Here we report a one-step approach, carried out under mild conditions, that exploits heteroepitaxial growth for the rapid fabrication of oriented polycrystalline MOF films on the centimetre scale. Our methodology employs crystalline copper hydroxide as a substrate and yields MOF films with oriented pore channels on scales that primarily depend on the dimensions of the substrate. To demonstrate that an anisotropic crystalline morphology can translate to a functional property, we assembled a centimetre-scale MOF film in the presence of a dye and showed that the optical response could be switched `ON’ or `OFF’ by simply rotating the film.

  3. Effect of preparation parameters on the microporous structure of Ni/SiO{sub 2} catalysts

    Energy Technology Data Exchange (ETDEWEB)

    Castillon, F.F.; Bodganchikova, N. [Centro de Investigacion Cientifica y de Educacion Superior, Ensenada (Mexico); Fuentes, S.; Avalos, M. [Univ. Nacional Autonoma de Mexico, Ensenada (Mexico). Inst. de Fisica

    1996-12-31

    In this work the authors report the synthesis of Ni/SiO{sub 2} catalysts promoted by group 2 (IIA) cations (calcium and barium) which are currently used as hydrogenation catalysts. The effect of the preparation parameters-aging, base agent, and type of cation, on the surface area of catalysts--is evaluated. Catalysts were prepared by precipitation of the precursor silicic acid, along with nickel nitrate and calcium and barium carbonates, with NaOH, NH{sub 4}OH and Na{sub 2}CO{sub 3} as precipitating agents. Catalysts were characterized by diffuse reflectance spectra (DRS) and by BET-surface area measurements. Results are discussed in terms of sol-gel chemistry.

  4. Synthesis and characterization of TiO2-pillared Romanian clay and their application for azoic dyes photodegradation.

    Science.gov (United States)

    Dvininov, E; Popovici, E; Pode, R; Cocheci, L; Barvinschi, P; Nica, V

    2009-08-15

    The synthesis and properties of metal oxide pillared cationic clays (PILCs) has been subject to numerous studies in the last decades. In order to obtain TiO(2)-pillared type materials, sodium montmorillonite from Romania-areal of Valea Chioarului, having the following composition (% wt): SiO(2)-72.87; Al(2)O(3)-14.5; MgO-2.15; Fe(2)O(3)-1.13; Na(2)O-0.60; K(2)O-0.60; CaO-0.90; PC-5.70 and cation exchange capacity, determined by ammonium acetate method, of 82 meq/100g, as matrix, was used. Sodium form of the clay was modified, primarily, by intercalation of cetyl-trimethylammonium cations between negatively charged layers which will lead to the expansion of the interlayer space. For the preparation of the TiO(2)-pillared clay, the alkoxide molecules, as titania precursor, were adsorbed onto/into clay samples (1 mmol Ti/g clay), in hydrochloric acid environment, the resulted species being converted into TiO(2) pillars by calcination. The as-prepared materials have been used as catalysts for Congo Red dye photodegradation, under UV. The photocatalytic activity of the pillared clays is a function of TiO(2) pillars size, their increase leading to the enhancement of the contact areas between dye solution and photoactive species present in the interlayer space. The structural characteristics and properties of the obtained materials were investigated by X-ray Diffraction, Thermogravimetry Analysis, UV-vis Diffuse Reflectance, Transmission Electron Microscopy and Energy Dispersive X-ray Analysis.

  5. Preparation and characterization of a micro-porous polymer electrolyte with cross-linking network structure for dye-sensitized solar cell

    Energy Technology Data Exchange (ETDEWEB)

    Wei, T.C.; Wan, C.C.; Wang, Y.Y. [Department of Chemical Engineering, National Tsing-Hua University, 101, Section 2, Kuang Fu Road, Hsin-Chu 300 (China)

    2007-12-14

    A PVdF-HFP/PEG/PEGDMA cross-linking film has been prepared as the electrolyte for dye-sensitized solar cell (DSSC). The film can be made porous by controlling the evaporation behavior of solvents. Room temperature ionic conductivity of the micro-porous film exceeds 1 mS/cm. In addition, we also evaluated the significance of cell gap in DSSC by analyzing the impedance spectroscopy of the cell with polymer electrolyte. Finally, by decreasing the film thickness, the DSSC equipped with 11 {mu}m, micro-porous and cross-linked film showed a conversion efficiency over 4% and 5% under 1 and 0.16 Sun, respectively. (author)

  6. Microporous spongy chitosan monoliths doped with graphene oxide as highly effective adsorbent for methyl orange and copper nitrate (Cu(NO3)2) ions.

    Science.gov (United States)

    Wang, Ying; Liu, Xu; Wang, Hongfang; Xia, Guangmei; Huang, Wei; Song, Rui

    2014-02-15

    In the current study, microporous spongy chitosan monoliths doped with small amount of graphene oxide (CSGO monoliths) with high porosity (96-98%), extraordinary high water absorption (more than 2000%) and low density (0.0436-0.0607 g cm(-3)) were prepared by the freeze-drying method and used as adsorbents for anionic dyes methyl orange (MO) and Cu(2+) ions. The adsorption behavior of the CSGO monoliths and influencing factors such as pH value, graphene oxide (GO) content, concentration of pollutants as well as adsorption kinetics were studied. Specifically, the saturated adsorption capacity for MO is 567.07 mg g(-1), the highest comparing with other publication results, and it is 53.69 mg g(-1) for Cu(2+) ions. Since they are biodegradable, non-toxic, efficient, low-cost and easy to prepare, we believe that these microporous spongy CSGO monoliths will be the promising candidates for water purification.

  7. Design and Syntheses of Conjugated Microporous Polymers%共轭微孔聚合物的设计与合成

    Institute of Scientific and Technical Information of China (English)

    许彦红; 姚婵

    2015-01-01

    Conjugated microporous polymers( CMPs)are a class of organic porous polymers that combine π-conjugated skeletons with permanent nanopores. It has attracted intensive attention due to well-controlled structure ,high surface areas,and good physical and chemical stability. This article focuses on the CMPs molecular design principles and methods of preparation.%共轭微孔聚合物( Conjugated Microporous Polymers,CMPs)是一类结合π-共轭骨架和永久性的纳米多孔结构的有机多孔聚合物,由于其结构可控,高的比表面积和良好的物理化学稳定性而日益受到人们的重视。这篇文章重点介绍了CMPs的分子设计原则和制备方法。

  8. A Tröger's base-derived microporous organic polymer: design and applications in CO2/H2 capture and hydrogenation of CO2 to formic acid.

    Science.gov (United States)

    Yang, Zhen-Zhen; Zhang, Hongye; Yu, Bo; Zhao, Yanfei; Ji, Guipeng; Liu, Zhimin

    2015-01-25

    A Tröger's base-derived microporous organic polymer (TB-MOP) was designed, which could adsorb CO2 and coordinate with a Ru(III) complex. The resultant TB-MOP-Ru showed good CO2 and H2 adsorbing performances, and high efficiency for catalysing hydrogenation of CO2 to HCOOH with a turnover number up to 2254 at 40 °C.

  9. Fabrication of a micro-porous Ti–Zr alloy by electroless reduction with a calcium reductant for electrolytic capacitor applications

    Energy Technology Data Exchange (ETDEWEB)

    Kikuchi, Tatsuya, E-mail: kiku@eng.hokudai.ac.jp [Faculty of Engineering, Hokkaido University, N13-W8, Kita-ku, Sapporo, Hokkaido 060-8628 (Japan); Yoshida, Masumi [Faculty of Engineering, Hokkaido University, N13-W8, Kita-ku, Sapporo, Hokkaido 060-8628 (Japan); Taguchi, Yoshiaki [Graduate School of Chemical Science and Engineering, Hokkaido University, N13-W8, Kita-ku, Sapporo, Hokkaido 060-8628 (Japan); Habazaki, Hiroki; Suzuki, Ryosuke O. [Faculty of Engineering, Hokkaido University, N13-W8, Kita-ku, Sapporo, Hokkaido 060-8628 (Japan)

    2014-02-15

    Highlights: • A metallic Ti–Zr alloy was obtained by electroless reduction for capacitor applications. • The reduction mechanisms were studied by SEM, XRD, EPMA, and an oxygen analyzer. • The alloy was obtained by electroless reduction in the presence of excess calcium reductant. • A micro-porous Ti–Zr alloy was successfully obtained. • The alloy has a low oxygen content and a large surface area. -- Abstract: A metallic titanium and zirconium micro-porous alloy for electrolytic capacitor applications was produced by electroless reduction with a calcium reductant in calcium chloride molten salt at 1173 K. Mixed TiO{sub 2}–70 at%ZrO{sub 2} oxides, metallic calcium, and calcium chloride were placed in a titanium crucible and heated under argon atmosphere to reduce the oxides with the calcium reductant. A metallic Ti–Zr alloy was obtained by electroless reduction in the presence of excess calcium reductant and showed a micro-porous morphology due to the sintering of each of the reduced particles during the reduction. The residual oxygen content and surface area of the reduced Ti–Zr alloy decreased over time during the electroless reduction. The element distributions were slightly different at the positions of the alloy and were in the composition range of Ti-69.3 at% to 74.3 at%Zr. A micro-porous Ti–Zr alloy with low oxygen content (0.20 wt%) and large surface area (0.55 m{sup 2} g{sup −1}) was successfully fabricated by electroless reduction under optimal conditions. The reduction mechanisms of the mixed and pure oxides by the calcium reductant are also discussed.

  10. Desenvolvimento de argamassas microporosas para a construção civil Development of microporous mortar for the civil construction

    Directory of Open Access Journals (Sweden)

    M. A. Coimbra

    1999-12-01

    Full Text Available Esse trabalho consistiu na obtenção e estudo de uma argamassa de peso leve para o uso na construção civil através da adição combinada, de aditivos formadores de microporosidade, mais a utilização de cargas que incorporam resíduos industriais. A técnica vem sendo recentemente apontada como uma promissora alternativa para a construção de estruturas leves, onde o compromisso da resistência mecânica aliada às ações ambientais, tais como degradações físico-químicas provocadas por intemperismo, não representam pré-requisitos básicos da construção civil, que possam impedir a utilização de argamassas de baixa densidade, com micro porosidade controlada. Assim sendo, esse trabalho utilizou aditivos adequados para a formação de bolhas estáveis, e quando necessário, agentes promotores de resistência mecânica, tais que puderam compensar perdas de resistência devido a presença excessiva das bolhas. A avaliação da influência dos aditivos, bem como do método de preparação das argamassas leves que incluem o mecanismo de mistura, o desenvolvimento microestrutural e propriedades são correlacionados, visando a obtenção de uma composição adequada que possa ser utilizada na fabricação de estruturas leves.The purpose of that work was to obtain a lightweight mortar for use in the civil construction through the combined addition of micropore chemical formers and industrial residues. Recently, the lightweight mortar technique has been pointed out as an alternative for the construction of light structures, where the commitment of the mechanical resistance associated with the climate actions, such as physical-chemical degradation caused by environmental actions, do not represent basic requirements for civil construction that could restrain the use of low density mortar, with micropore controlled structure. The work analysed the influence of additives adapted for the formation of stable bubbles, and in some cases, the use of

  11. 有机微孔聚合物研究进展%Research Progress on Microporous Organic Polymers

    Institute of Scientific and Technical Information of China (English)

    徐叔军; 梁丽芸; 李步怡; 罗亚莉; 刘承美; 谭必恩

    2011-01-01

    Microporous organic polymers(MOPs) are a new type of porous materials,which have advantages with synthetic diversity,chemical and physical stability,pore size controllability,and pore surface modifiability.In recent years,MOPs have attracted an enormous attention in energy gas storage and greenhouse gas capture due to their great potential physisorptive gas storage.This paper describes the structure and characteristics of MOPs.The four different kinds of MOPs,such as polymers of intrinsic microporosity(PIMs),hyper-crosslinked polymers(HCPs),covalent organic frameworks(COFs) and conjugated microporous polymers(CMPs) are introduced respectively,including the recent research progress and the relationship between structures and properties.The applications of MOPs such as catalysis,separations and gas storage are discussed briefly.We also discuss the development of MOPs in future.%有机微孔聚合物(MOPs)是一类新型的多孔材料,具有合成方法多样、化学和物理性质稳定、孔尺寸可调控、表面可修饰等优点。近年来,MOPs在物理吸附储存气体方面表现出巨大潜力,从而在储氢和温室气体封存方面成为研究的热点之一。本文首先介绍了MOPs的结构类型及特点,分别介绍了自具微孔聚合物、超交联聚合物、共价有机网络以及共轭微孔聚合物的最新进展,分析结构与性能间的关系,并对其在催化、分离和气体储存方面的应用做了简单总结。最后对MOPs未来的研究进行了展望。

  12. Gas Permeation and Physical Aging Properties of Iptycene Diamine-Based Microporous Polyimides

    KAUST Repository

    Alghunaimi, Fahd

    2015-05-12

    The synthesis and gas permeation properties of two 6FDA-dianhydride-based polyimides prepared from 2,6-diaminotriptycene (6FDA-DAT1) and its extended iptycene analog (6FDA-DAT2) are reported. The additional benzene ring on the extended triptycene moiety in 6FDA–DAT2 increases the free volume over 6FDA-DAT1 and reduces the chain packing efficiency. The BET surface area based on nitrogen adsorption in 6FDA-DAT2 (450 m2g−1) is ~40% greater than that of 6FDA-DAT1 (320 m2g−1). 6FDA-DAT1 shows a CO2 permeability of 120 Barrer and CO2/CH4 selectivity of 38, whereas 6FDA-DAT2 exhibits a 75% increase in CO2 permeability to 210 Barrer coupled with a moderate decrease in selectivity (CO2/CH4=30). Interestingly, minimal physical aging was observed over 150 days for both polymers and attributed to the high internal free volume of the shape-persistent iptycene geometries. The aged polyimides maintained CO2/CH4 selectivities of 25-35 along with high CO2 permeabilities of 90-120 Barrer up to partial CO2 pressures of 10 bar of an aggressive 50:50 CO2:CH4 mixed-gas feed, suggesting potential application in membranes for natural gas sweetening.

  13. Effect of phase inversion on microporous structure development of Al 2O 3/poly(vinylidene fluoride-hexafluoropropylene)-based ceramic composite separators for lithium-ion batteries

    Science.gov (United States)

    Jeong, Hyun-Seok; Kim, Dong-Won; Jeong, Yeon Uk; Lee, Sang-Young

    To improve the thermal shrinkage of the separators that are essential to securing the electrical isolation between electrodes in lithium-ion batteries, we develop a new separator based on a ceramic composite membrane. Introduction of microporous, ceramic coating layers onto both sides of a polyethylene (PE) separator allows such a progress. The ceramic coating layers consist of nano-sized alumina (Al 2O 3) powders and polymeric binders (PVdF-HFP). The microporous structure of the ceramic coating layers is observed to be crucial to governing the thermal shrinkage as well as the ionic transport of the ceramic composite separators. This microporous structure is determined by controlling the phase inversion, more specifically, nonsolvent (water) contents in the coating solutions. To provide a theoretical basis for this approach, a pre-investigation on the phase diagram for a ternary mixture comprising PVdF-HFP, acetone, and water is conducted. On the basis of this observation, the effect of phase inversion on the morphology and air permeability (i.e. Gurley value) of ceramic coating layers is systematically discussed. In addition, to explore the application of ceramic composite separators to lithium-ion batteries, the influence of the structural change in the coating layers on the thermal shrinkage and electrochemical performance of the separators is quantitatively identified.

  14. 污水处理厂微孔曝气器选型的探讨%Discussion of Selecting Microporous Aerator in Sewage Treatment Plant

    Institute of Scientific and Technical Information of China (English)

    周鹏飞

    2013-01-01

    Aerator is the core equipment of sewage treatment plant. Current prevalent microporous aeration is an effective and energy-saving aeration mode. It's very important to select feasible microporous aerator. It should not only ensure stable operation and low cost, but also save equipment investment and maintenance costs. Based on the application effect in sewage treatment plant, analyzed characteristics, merits and advantages of several microposous aerators and discussed the selection of microporous aerators.%曝气器是污水处理厂的核心设备.目前广泛运用的鼓风机微孔曝气是一种高效节能的曝气方式.选择适当的微孔曝气器是非常重要的,不仅保障污水处理效果稳定,运行成本较低,还能节省设备投资和维护费用.结合微孔曝气器在污水处理厂的运用效果,分析了各种微孔曝气器的性能、特点和优劣,并对污水处理厂微孔曝气器的选型进行了探讨.

  15. Ruthenium oxide/carbon composites with microporous or mesoporous carbon as support and prepared by two procedures. A comparative study as supercapacitor electrodes

    Energy Technology Data Exchange (ETDEWEB)

    Pico, F. [Instituto de Ciencia de Materiales de Madrid (ICMM), Consejo Superior de Investigaciones Cientificas (CSIC), Sor Juana Ines de la Cruz 3, Cantoblanco, E-28049-Madrid (Spain); Morales, E. [Instituto de Ciencia y Tecnologia de Polimeros (ICTP), CSIC, Juan de la Cierva 3, E-28006-Madrid (Spain); Fernandez, J.A.; Centeno, T.A. [Instituto Nacional del Carbon (INCAR), CSIC, Francisco Pintado Fe 26, E-33011-Oviedo (Spain); Ibanez, J. [Centro Nacional de Investigaciones Metalurgicas (CENIM), CSIC, Avda. Gregorio del Amo 8, E-28040-Madrid (Spain); Rojas, R.M.; Amarilla, J.M. [Instituto de Ciencia de Materiales de Madrid (ICMM), Consejo Superior de Investigaciones Cientificas (CSIC), Sor Juana Ines de la Cruz 3, Cantoblanco, E-28049-Madrid (Spain); Rojo, J.M. [Instituto de Ciencia de Materiales de Madrid (ICMM), Consejo Superior de Investigaciones Cientificas (CSIC), Sor Juana Ines de la Cruz 3, Cantoblanco, E-28049-Madrid (Spain)], E-mail: jmrojo@icmm.csic.es

    2009-03-01

    Composites are prepared by deposition of nanoparticles of RuO{sub 2}.xH{sub 2}O (1-4 nm) on two carbons: microporous carbon (1.3 nm of average micropore size) and mesoporous carbon (11 nm of average mesopore size). Two-preparation procedures are used: (i) procedure A consisting of repetitive impregnations of the carbons with RuCl{sub 3}.0.5H{sub 2}O solutions, and (ii) procedure B based on impregnation of the carbons with Ru(acac){sub 3} vapour. The procedure B leads to supported RuO{sub 2}.xH{sub 2}O particles that appear more crystalline than those obtained by the procedure A. Specific capacitance and specific surface area of the composites are discussed as functions of the RuO{sub 2} content, and different dependences for the composites derived from the two carbons are found. Mesoporous carbon is better support than microporous carbon. Procedure A leads to supported RuO{sub 2}.xH{sub 2}O particles with higher specific capacitance than the particles deposited by procedure B.

  16. Microporous Ni@NiO nanoparticles prepared by chemically dealloying Al3Ni2@Al nanoparticles as a high microwave absorption material

    Science.gov (United States)

    Pang, Yu; Xie, Xiubo; Li, Da; Chou, Wusheng; Liu, Tong

    2017-03-01

    The Al3Ni2@Al nanoparticles (NPs) were prepared from Ni45Al55 master alloy by hydrogen plasma-metal reaction method, and were subsequently dealloyed to produce porous Ni@NiO NPs of 36 nm. The pore size ranges from 0.7 to 1.6 nm, leading to large specific surface area of 69.5 m2/g and big pore volume of 0.507 cc/g. The saturation magnetization (MS) and coercivity (HC) of the microporous Ni@NiO NPs are 11.5 emu/g and 5.2 Oe. They exhibit high microwave absorption performance with a minimum reflection coefficient (RC) of -86.9 dB and an absorption bandwidth of 2.6 GHz (RC≤-10 dB) at thickness of 4.5 mm. The enhanced microwave absorption properties are attributed to the synergistic effect of the magnetic Ni core and dielectric NiO shell, and the micropore architecture. The NPs with micropore morphology and core/shell structure open a new way to modify the microwave absorption performance.

  17. PREPARATION OF MICROPOROUS ULTRA HIGH MOLECULAR WEIGHT POLYETHYLENE (UHMWPE) BY THERMALLY INDUCED PHASE SEPARATION OF A UHMWPE/LIQUID PARAFFIN MIXTURE

    Institute of Scientific and Technical Information of China (English)

    Lie Shen; Mao Peng; Fei Qiao; Jie-lai Zhang

    2008-01-01

    Ultra-high molecular weight polyethylene (UHMWPE) with a microporous structure was prepared via thermally induced phase separation (TIPS).Liquid paraffin (LP) was used as a diluent in the preparation of microporous UHMWPE.Small angle laser light scattering (SALLS) and differential scanning calorimetry (DSC) were used to determine the phase separation temperatures,I.e.the cloud points and the dynamic crystallization temperatures,respectively.It was found that the cloud points were coincident with the crystallization temperatures,indicating that a solid-liquid phase separation occurred during thermal quenching of the UHMWPE/LP solution,while,no liquid-liquid phase separation above the crystallization temperature was observed.The effects of the content and the molecular weight of UHMWPE on the morphology and average pore size were investigated with field emission scanning electron microscopy (FE-SEM) and mercury porosimetry.With the increase of the content of UHMWPE,the average pore size of the microporous material decreased and the molecular weight of UHMWPE could also influence the pore size slightly.

  18. Impregnación de platino y dimensión fractal en dos tipos de sólidos microporosos Platinum impregnation and fractal dimension on two types of micro-porous solids

    Directory of Open Access Journals (Sweden)

    José G. Carriazo

    2010-01-01

    Full Text Available El presente trabajo muestra la modificación de una zeolita-Y y una arcilla pilarizada (tipo saponita mediante impregnación con diferentes cargas de Pt (catalizadores a base de Pt. Los sólidos se caracterizaron en cuanto a su composición química y su textura. La caracterización textural revela cambios importantes en los sólidos, mostrando que se genera microporosidad en la serie de catalizadores zeolíticos y se bloquean las estructuras microporosas en la serie de catalizadores obtenidos a partir de la arcilla pilarizada. La determinación de la dimensión fractal (mediante el método de Avnir-Jaroniec indica que la modificación con Pt afecta significativamente las características topográficas de la superficie de la arcilla pilarizada como consecuencia de la posible formación de agregados de Pt.This research shows the modification of a zeolite Y and a pillared clay (saponite by impregnation with different platinum quantities (synthesis of Pt catalysts. The solids were characterized about the chemical composition and texture. The textural characterization reveals important changes in the solids, showing that in the zeolitic catalysts microporosity is formed, whereas in the pillared clay the microporous structures are partially blocked. Fractal dimension (by Avnir-Jaroniec method indicates that the topographic features of the pillared clay surface are significantly affected due to the modification with platinum, probably as a consequence of platinum clusters formation.

  19. Optimisation of the microporous layer for a polybenzimidazole-based high temperature PEMFC - effect of carbon content

    Energy Technology Data Exchange (ETDEWEB)

    Lobato, J.; Canizares, P.; Rodrigo, M.A.; Ubeda, D.; Pinar, F.J.; Linares, J.J. [Department of Chemical Engineering, University of Castilla-La Mancha, Av. Camilo Jose Cela, n 12. 13071, Ciudad Real (Spain)

    2010-10-15

    This work aims at studying the role of the microporous layer (MPL) in electrodes prepared for high temperature PBI-based PEMFC. The two main components of this layer are carbon black and a polymeric binder (Teflon). This work addresses the effect of the MPL carbon amount on the performance of a high temperature PEMFC. Thus, gas diffusion layers (GDLs) containing MPL with different carbon contents (from 0.5 to 4 mg cm{sup -2}) were prepared. Firstly, they were physically characterised by Hg-porosimetry measuring pore size distribution, porosity, tortuosity and mean pore size. Permeability measurements were also performed. The higher the carbon content was the lower both porosity and permeability were. Afterwards, electrodes were prepared with these GDLs and were electrochemically characterised. Electrochemical surface area (ESA) was determined and fuel cell performance was evaluated under different fuel and comburent stoichiometries, supporting these results with impedance spectra. This made it possible to see the benefits of the MPL inclusion in the electrode structure, with a significant increase in the fuel cell performance and ESA. Once the goodness of the MPL was confirmed, result analysis led to an optimum MPL composition of 2 mg cm{sup -2} of carbon for both electrodes, anode and cathode. (Abstract Copyright [2010], Wiley Periodicals, Inc.)

  20. Feasibility of clinoptilolite application as a microporous carrier for pH-controlled oral delivery of aspirin.

    Science.gov (United States)

    Tondar, Mahdi; Parsa, Mohammad Javad; Yousefpour, Yaser; Sharifi, Ali Mohammad; Shetab-Boushehri, Seyed Vahid

    2014-01-01

    Clinoptilolite is a natural zeolite which due to high surface area/volume ratio has found many applications in industries and medicine. Aspirin is a non-steroidal anti-inflammatory drug which is currently used as an anticoagulant, antinociceptive, antipyretic, and anti-inflammatory drug. It is an acidic drug which induces gastric irritation due to inhibition of cyclooxygenase I located in gastric mucosa. In the present work, adsorption and desorption of aspirin on Iranian clinoptilolite micronized particles were studied in acidic and relatively alkaline pHs. Effect of particle size of clinoptilolite was also investigated on adsorption and desorption of aspirin. Specific surfaces, particle sizes, and zeta potentials of clinoptilolite particles were also determined. Scanning electron micrograph was used to study the morphology and crystallinity of clinoptilolite particles. The results showed that adsorption and desorption of aspirin on clinoptilolite are particle size- and pH-dependent. The present work proposes clinoptilolite as an inexpensive, efficient, and non-toxic natural available microporous material for aspirin oral delivery.

  1. Surface Modification of Polypropylene Microporous Membrane by Atmospheric-pressure Plasma Induced N-vinyl-2-pyrrolidone Graft Polymerization

    Institute of Scientific and Technical Information of China (English)

    ZHONG Shaofeng

    2012-01-01

    Membrane surfaces modified with poly(N-vinyl-2-pyrrolidone) (PNVP) can be endowed with hydrophilicity,biocompatibility and functionality.In this work,atmospheric pressure dielectric barrier discharge plasma graft polymerization of N-vinyl-2-pyrrolidone (NVP) onto polypropylene (PP) microporous membrane surface was studied.The experimental results reveal that plasma treatment conditions,such as discharge power,treatment time and adsorbed NVP amount,have remarkable effects on the grafting degree of NVP.Structural and morphological changes on the membrane surfaces were characterized by attenuated total reflection-Fourier transform infrared spectroscopy (FT-IR/ATR),X-ray photoelectron spectroscope (XPS) and field emission scanning electron microscopy (FE-SEM).Water contact angles of the membrane surfaces were also measured by the sessile drop method.Water contact angles on the membrane surfaces decrease with the increase of NVP grafting degree,which indicates an enhanced hydrophilicity for the modified membranes.The effects of grafting degrees on pure water fluxes were also measured.It is shown that pure water fluxes increase with grafting degree firstly and then decrease adversely.Finally,filtration of bovine serum albumin (BSA) solution and platelets adhesion of the PNVP modified membranes show good protein resistance and potential biocompatibility due to the enhancement of surface hydrophilicity.

  2. Application of a self-supporting microporous layer to gas diffusion layers of proton exchange membrane fuel cells

    Science.gov (United States)

    Ito, Hiroshi; Heo, Yun; Ishida, Masayoshi; Nakano, Akihiro; Someya, Satoshi; Munakata, Tetsuo

    2017-02-01

    The intrinsic effect of properties of a self-supporting microporous layer (MPL) on the performance of proton exchange membrane fuel cells (PEMFCs) is identified. First, a self-supporting MPL is fabricated and applied to a gas diffusion layer (GDL) of a PEMFC, when the GDL is either an integrated sample composed of a gas diffusion backing (GDB, i.e., carbon paper) combined with MPL or a sample with only MPL. Cell performance tests reveal that, the same as the MPL fabricated by the coating method, the self-supporting MPL on the GDB improves the cell performance at high current density. Furthermore, the GDL composed only of the MPL (i.e., GDB-free GDL) shows better performance than does the integrated GDB/MPL GDL. These results along with literature data strongly suggest that the low thermal conductivity of MPL induces a high temperature throughout the GDL, and thus vapor diffusion is dominant in the transport of product water through the MPL.

  3. Effect of annealing and UV-radiation time over micropore architecture of self-assembled block copolymer thin film

    Directory of Open Access Journals (Sweden)

    G. del C. Pizarro

    2015-06-01

    Full Text Available Block copolymers have been recognized as versatile materials to prepare nanoporous polymer films or membranes, but their potential has not been completely explored. This study focuses on the formation and characterization of nanoporous polymer films based on poly(styrene-block-(methylmethacrylate/methacrylic acid; (PS-b-MMA/MAA were obtained through atom transfer radical polymerization (ATRP, by using two different protocols: annealing and annealingirradiation; for improving the formation of microporous surface. The composition, crystallinity and structural order of the films were studied by Raman spectroscopy. The film polymer thickness was obtained through very high resolution ellipsometry (VHRE. Finally, atomic force microcopy (AFM and scanning electron microscopy (SEM techniques were used to detect changes in the porous-structure. These results show that the morphological properties of the block copolymer were affected via the modification of two variables, UV-radiation time and annealing. SEM and AFM micrographs showed that the morphology exhibit a porous ordered structure. Contact angle measurement suggests additional interactions between hydrophilic functional groups that influence the film wettability.

  4. Preparation, characterization, and silanization of 3D microporous PDMS structure with properly sized pores for endothelial cell culture.

    Science.gov (United States)

    Zargar, Reyhaneh; Nourmohammadi, Jhamak; Amoabediny, Ghassem

    2016-01-01

    Nowadays, application of porous polydimethylsiloxane (PDMS) structure in biomedical is becoming widespread, and many methods have been established to create such structure. Although the pores created through these methods are mostly developed on the outer surface of PDMS membrane, this study offers a simple and cost-efficient technique for creating three-dimensional (3D) microporous PDMS structure with appropriate pore size for endothelial cell culture. In this study, combination of gas foaming and particulate leaching methods, with NaHCO3 as effervescent salt and NaCl as progen are used to form a 3D PDMS sponge. The in situ chemical reaction between NaHCO3 and HCl resulted in the formation of small pores and channels. Moreover, soaking the samples in HCl solution temporarily improved the hydrophilicity of PDMS, which then facilitated the penetration of water for further leaching of NaCl. The surface chemical modification process was performed by (3-aminopropyl)triethoxysilane to culture endothelial cells on porous PDMS matrix. The results are an indication of positive response of endothelial cells to the fabricated PDMS sponge. Because of simplicity and practicality of this method for preparing PDMS sponge with appropriate pore size and biological properties, the fabricated matrix can perfectly be applied to future studies in blood-contacting devices. © 2015 International Union of Biochemistry and Molecular Biology, Inc.

  5. Surface modification of polypropylene microporous membrane to improve its antifouling characteristics in an SMBR: N2 plasma treatment.

    Science.gov (United States)

    Yu, Hai-Yin; He, Xiao-Chun; Liu, Lan-Qin; Gu, Jia-Shan; Wei, Xian-Wen

    2007-12-01

    Fouling is the major obstacle in membrane processes applied in water and wastewater treatment. The polypropylene hollow fiber microporous membranes (PPHFMMs) were surface modified by N(2) low-temperature plasma treatment to improve the antifouling characteristics. Morphological changes on the membrane surface were characterized by field emission scanning electron microscopy (FE-SEM). The change of surface wettability was monitored by contact angle measurements. The static water contact angle of the modified membrane reduced obviously; the relative pure water flux of the modified membranes increased with the increase of plasma treatment time. To assess the relation between plasma treatment and membrane fouling in a submerged membrane bioreactor (SMBR), filtration of activated sludge was carried out by using synthetic wastewater. After continuous operation in the SMBR for about 90 h, flux recoveries for the N(2) plasma-treated PPHFMM for 8 min were 62.9% and 67.8% higher than those of the virgin membrane after water and NaOH cleaning. The irreversible fouling resistance decreased after plasma treatment.

  6. Improving amphiphilic polypropylenes by grafting poly(vinylpyrrolidone) and poly(ethylene glycol) methacrylate segments on a polypropylene microporous membrane

    Science.gov (United States)

    Chen, Huirong; Ma, Wenzhong; Xia, Yanping; Gu, Yi; Cao, Zheng; Liu, Chunlin; Yang, Haicun; Tao, Shengxi; Geng, Haoran; Tao, Guoliang; Matsuyama, Hideto

    2017-10-01

    An amphiphilic polypropylene-g-poly[vinylpyrrolidone-co-poly(ethylene glycol) methacrylate] (PP-g-(NVP-co-PEGMA)) modifier was prepared by melt grafting polymerization using N-vinyl pyrrolidone (NVP) as the grafting monomer and poly(ethylene glycol) (PEGMA) as the comonomer. Fourier transform infrared (FTIR) spectroscopy and elemental analysis showed that the hydrophilic branched chains (NVP-g-PEGMA) were successfully grafted to polypropylene (PP) macromolecular chains. The largest NVP grafting degree for PP-g-(NVP-co-PEGMA) (up to 20.4%) was obtained when the mass ratio of PP/NVP/PEGMA was 100/30/15. Hydrophilic PP microporous membranes were prepared by stretching cast films of PP/PP-g-(NVP-co-PEGMA) blends. The membrane thermostability (including the modifier) was better than that of the pure PP membrane with a similar surface pore structure. The porosity of the modified membranes was only slightly lower than that of the pure PP membranes. Contact angle measurements were used to examine the hydrophilicity of the membranes. The water contact angle of the membranes decreased when PP-g-(NVP-co-PEGMA) was added, and the minimum contact angle was 64.5°. Therefore, this work provides a good application for stretched hydrophilic PP membrane fabrication.

  7. Direct Observation of Xe and Kr Adsorption in a Xe-Selective Microporous Metal-Organic Framework.

    Science.gov (United States)

    Chen, Xianyin; Plonka, Anna M; Banerjee, Debasis; Krishna, Rajamani; Schaef, Herbert T; Ghose, Sanjit; Thallapally, Praveen K; Parise, John B

    2015-06-10

    The cryogenic separation of noble gases is energy-intensive and expensive, especially when low concentrations are involved. Metal-organic frameworks (MOFs) containing polarizing groups within their pore spaces are predicted to be efficient Xe/Kr solid-state adsorbents, but no experimental insights into the nature of the Xe-network interaction are available to date. Here we report a new microporous MOF (designated SBMOF-2) that is selective toward Xe over Kr under ambient conditions, with a Xe/Kr selectivity of about 10 and a Xe capacity of 27.07 wt % at 298 K. Single-crystal diffraction results show that the Xe selectivity may be attributed to the specific geometry of the pores, forming cages built with phenyl rings and enriched with polar -OH groups, both of which serve as strong adsorption sites for polarizable Xe gas. The Xe/Kr separation in SBMOF-2 was investigated with experimental and computational breakthrough methods. These experiments showed that Kr broke through the column first, followed by Xe, which confirmed that SBMOF-2 has a real practical potential for separating Xe from Kr. Calculations showed that the capacity and adsorption selectivity of SBMOF-2 are comparable to those of the best-performing unmodified MOFs such as NiMOF-74 or Co formate.

  8. Influence of the Joule-Thomson effect on the flow of a vapor through a micro-porous membrane

    Science.gov (United States)

    Loimer, Thomas

    2005-11-01

    The flow of a fluid near saturation through a micro-porous membrane is considered. Upstream of the membrane, the fluid is in a state of saturated vapor. Downstreams, there is unsaturated vapor which is, due to the Joule-Thomson effect, cooler than at the upstream side. The flow is described taking into account the Joule-Thomson effect and the wetting properties between the fluid and the membrane material, i.e., the capillary pressure across a curved meniscus and capillary condensation. Different types of flow occur, depending on the permeability of the membrane, on the wetting properties between the fluid and the membrane and on the pressure difference. The fluid condenses either fully or partially at the front surface of the membrane, or a liquid film forms in front of the membrane. Liquid or a two-phase mixture flows through a part or all of the membrane and evaporates either within the membrane or at the downstream front of the membrane, or the fluid evaporates at the upstream front of the membrane and vapor flows through the entire membrane. The different types of flow are discussed and the conditions under which they occur are presented.

  9. XPS study and physico-chemical properties of nitrogen-enriched microporous activated carbon from high volatile bituminous coal

    Energy Technology Data Exchange (ETDEWEB)

    Robert Pietrzak [Adam Mickiewicz University, Poznan (Poland). Laboratory of Coal Chemistry and Technology

    2009-10-15

    N-enriched microporous active carbons of different physico-chemical parameters have been obtained from high volatile bituminous coal subjected to the processes of ammoxidation, carbonisation and activation in different sequences. Ammoxidation was performed by a mixture of ammonia and air at the ratio 1:3 (flow ratio 250 ml/min:750 ml/min) at 350{sup o}C, at each stage of production i.e. that of precursor, carbonisate and active carbon. Ammoxidation performed at the stage of demineralised coal or carbonisate has been shown to lead to a significant nitrogen enrichment and to have beneficial effect on the porous structure of the carbon during activation, allowing obtaining samples of the surface area of 2600-2800 m{sup 2}/g and pore volume 1.29-1.60 cm{sup 3}/g to be obtained with the yield of about 50%. The amount of nitrogen introduced into the carbon structure was found to depend on the sequence of the processes applied. The greatest amount of nitrogen was introduced for the processes in the sequence carbonisation {yields} activation {yields} ammoxidation. The introduction of nitrogen at the stage of active carbon leads to a reduction in the surface area and lowering of its sorption capacity. From the XPS study, ammoxidation introduces nitrogen mainly in the form of imines, amines, amides, N-5 and N-6, irrespective of the processing stage at which it is applied. 40 refs., 2 figs., 5 tabs.

  10. 铜电化学沉积在微孔金属化中的应用%Application of Copper Electrochemical Deposition for the Metallization of Micropores

    Institute of Scientific and Technical Information of China (English)

    杨防祖; 吴伟刚; 田中群; 周绍民

    2011-01-01

    以分布有微孔的印刷线路板(PCB)作为模板,按照PCB孔金属化工艺路线,研究乙醛酸化学镀铜和柠檬酸盐体系铜电沉积工艺在PCB微孔金属化中的应用.结果表明,乙醛酸化学镀铜和柠檬酸盐体系电沉积铜可以成功地应用于PCB微孔金属化加工工艺中.微孔化学镀铜金属化导电处理后,铜附着于微孔内壁,颗粒细小,但排列疏松且局部区域发生漏镀现象.微孔一经电镀铜加厚,镀层电阻显著下降;孔壁内外的铜沉积速率达到0.8∶1.0;铜颗粒具有一定的侧向生长能力,能够完全覆盖化学镀铜时产生的微小漏镀区域;微孔内壁铜镀层连续、结构致密并紧密附着于内壁,大大增强了PCB 上下层互连的导电性能.%According to established routes for the microporous metallization of printed circuit boards (PCB), electroless copper plating using glyoxylic acid as a reducing agent and copper electroplating in a citrate bath were used for microporous metallization with PCB distributing micropores as a template. The results show that electroless copper plating using glyoxylic acid as a reducing agent and copper electroplating in a citrate bath can be successfully applied to the microporous metallization of PCB. After an electric conducting treatment of the micropores by electroless copper plating the copper deposited as fine grains and attached to the inner walls of the micropores. The copper deposit was also found in the loose grain arrangement and the leak plating area. Immediately after thickening treatment by copper electroplating, the resistance toward the copper coating of the inner wall decreased notably. The ratio of the copper electroplating rates at the inner and outer micropores was found to be 0.8:1.0. The copper electrodeposit fully covered the surface of the inner wall including the leak plating area, which means that the electroplated copper grains have a certain sideway growing ability. The copper coating on the

  11. 微波前处理酶法制备微孔淀粉研究%Study on Preparation of Microporous Starch by Enzymatic Method after Microwave Pretreatment

    Institute of Scientific and Technical Information of China (English)

    李维杰; 杨光; 刘灿召; 耿玮蔚; 袁超

    2009-01-01

    [Objective] The study was to increase the adsorption properties of microporous starch, and shorten its production time. [Method] With native corn starch as the material, it was treated by ultrasonic with 40 W/g for 10 min, and then the microporous starch was prepared by pH buffer of α-amylase and glucosidase. The effects of factors on oil absorption ratio of microporous starch were studied. [Result]When other factors were fixed, the oil absorption ratio of microporous starch was the lowest when reaction temperature was 30 ℃ and it was higher when reaction temperature was 50-55 ℃. The oil absorption ratio of microporous starch was higher when pH value of the buffer was 5.0-5.5, but it was decreased sharply when pH value of the buffer was higher than 5.5. When pH value of the buffer was 5.0, reaction temperature was 50 ℃, reaction time was 12 h with α-amylase amount of 75 U/g and glucosidase amount of 46 U/g, the oil absorption ratio of microporous starch was the highest, reaching 132.8%. [Conclusion] Microwave pretreatment could increase the oil absorption ratio of microporous starch.%[目的] 提高微孔淀粉的吸附性能,缩短其生产时间.[方法] 以玉米原淀粉为材料,对其施加40 W/g的超声波处理10 min,然后用α-淀粉酶和葡萄糖苷酶的pH缓冲液制备微孔淀粉,研究各因素对微孔淀粉吸油率的影响.[结果] 其他因素固定不变,当反应温度为30 ℃时,微孔淀粉的吸油率最低,反应温度在50~55 ℃时,微孔淀粉的吸油率较高;缓冲液pH值在5.0~5.5时,微孔淀粉的吸油率较高,缓冲液pH值高于5.5时,微孔淀粉的吸油率急剧下降;当缓冲液pH值为5.0,反应温度为50 ℃,反应时间为12 h,α-淀粉酶用量为75 U/g,葡萄糖苷酶用量为46 U/g时,微孔淀粉的吸油率最高,达132.8%.[结论] 微波预处理可提高微孔淀粉的吸油率.

  12. Role of binder in the synthesis of titania membrane

    Indian Academy of Sciences (India)

    K S Seshadri; M Selvaraj; R Kesava Moorthy; K Varatharajan; M P Srinivasan; K B Lal

    2003-02-01

    The synthesis of titania membrane through sol–gel route involves hydrolysis of alkoxide, peptization of hydrous oxide of titanium to obtain a sol, adjustment of the sol viscosity by including a binder and filtration of the viscous sol through a microporous support, gelation and sintering to desired temperature. The binder plays an important role in that it not only helps in adjustment of sol viscosity but also helps in binding the sol particle with porous support. Here a comparative study on the role of different binders, viz. polyvinyl alcohol, polyethyleneimine, polyacrylamide, effect of their viscosity and surface tension effect on the morphology of the titania membrane is presented. The results show that among the three binders studied polyvinyl alcohol gave rise to membranes of desired characteristics when the sol viscosity was 0.08 pa.s.

  13. Superior capture of CO2 achieved by introducing extra-framework cations into N-doped microporous carbon

    KAUST Repository

    Zhao, Yunfeng

    2012-12-21

    We designed and prepared a novel microporous carbon material (KNC-A-K) for selective CO2 capture. The combination of a high N-doping concentration (>10 wt %) and extra-framework cations, which were introduced into carbonaceous sorbents for the first time, endowed KNC-A-K with exceptional CO2 adsorption capabilities, especially at low pressures. Specifically, KNC-A-K exhibited CO2 uptake of 1.62 mmol g -1 at 25 C and 0.1 bar, far exceeding the CO2 adsorption capability of most reported carbon material to date. Single component adsorption isotherms indicated that its CO2/N2 selectivity was 48, which also significantly surpasses the selectivity of conventional carbon materials. Furthermore, breakthrough experiments were conducted to evaluate the CO2 separation capability of KNC-A-K on CO2/N2 (10:90 v/v) mixtures under kinetic flow conditions, and the obtained CO 2/N2 selectivity was as high as 44, comparable to that predicted from equilibrium adsorption data. Upon facile regeneration, KNC-A-K showed constant CO2 adsorption capacity and selectivity during multiple mixed-gas separation cycles. Its outstanding low-pressure CO 2 adsorption ability makes KNC-A-K a promising candidate for selective CO2 capture from flue gas. Theoretical calculations indicated that K+ ions play a key role in promoting CO2 adsorption via electrostatic interactions. In addition, we found that HCl molecules anchored in N-doped carbon have a similar promotion effect on CO 2 adsorption, which contradicts the conventional wisdom that the neutralization of basic sites by acids diminishes the adsorption of acidic CO2 gas. © 2012 American Chemical Society.

  14. Characteristics and controlling factors of micropore structures of the Longmaxi Shale in the Jiaoshiba area, Sichuan Basin

    Directory of Open Access Journals (Sweden)

    Xusheng Guo

    2014-12-01

    Full Text Available Pore structures in shales are a main factor affecting the storage capacity and production performance of shale gas reservoirs. Taking Longmaxi Shales in the Jiaoshiba area of the Sichuan Basin as a study object, we systematically study the microscopic pore structures of shales by using Argon-ion polishing Scanning Electron Microscope (SEM, high-pressure mercury injection and low-temperature nitrogen adsorption and desorption experiments. The study results show that: the Longmaxi Shale in this area are dominated by nano-scale pores which can be classified into organic pores, inorganic pores (intergranular pores, intragranular pores, inter-crystalline pores and dissolution pores, microfractures (intragranular structure fractures, interlayer sliding fractures, diagenetic shrinkage joints and abnormal-pressure fractures from organic evolution, among which organic pores and clay mineral pores are predominant and organic pores are the most common; a TOC value shows an obvious positive correlation with the content of organic pores, which account for up to 50% in the lower-quality shales with a TOC of over 2% where they are most developed; microscopic pore structures are very complex and open, with pores being mainly in cylinder shape with two ends open, or in parallel tabular shape with four sides open and 2–30 nm in diameter, being mostly medium pores. On this basis, factors affecting the micropore structures of shales in this area are studied. It is concluded that organic matter abundance and thermal maturity are the major factors controlling the microscopic pore structures of shales, while the effects of clay mineral content are relatively insignificant.

  15. Evaluation of pharmacokinetics and pharmacodynamics relationships for Salvianolic Acid B micro-porous osmotic pump pellets in angina pectoris rabbit

    Directory of Open Access Journals (Sweden)

    Shu-Ling Kan

    2014-06-01

    Full Text Available The work aims to investigate the in vitro release, pharmacokinetics (PK, pharmacodynamics (PD and PK–PD relationships of Salvianolic Acid B micro-porous osmotic pump pellets (SalB-MPOPs in angina pectoris New Zealand White (NZW rabbits, compared with those of SalB immediate-release pellets (SalB-IRPs. The SalB plasma concentrations and Superoxide dismutase levels (PD index were recorded continuously at predetermined time interval after administration, and the related parameters were calculated by using WinNonlin software. The release profile of MPOPs was more sustained than that of IRPs. PK results indicated that the mean Cmax was significantly lower, the SalB plasma concentrations were steadier, both area under concentration-time curve from 0 to 24 h (AUC0–24 h and from 0 to infinity (AUC0–∞ were presented larger, and both the peak concentration time (Tmax and mean residence time (MRT were prolonged for MPOPs, as compared with those of IRPs. PD results suggested that peak drug effect (Emax was lower and the equilibration rate constant (ke0 between the central compartment and the effect compartment was higher of MPOPs vs. those of IRPs. PK–PD relationships demonstrated that the effect-concentration-time (ECT course of MPOPs was clockwise hysteresis loop, and that of IRPs was counter-clockwise hysteresis loop. Collectively, those results demonstrated that MPOPs were potential formulations in treating angina pectoris induced by atherosclerosis.

  16. 交联微孔木薯淀粉的制备及其性能研究%Preparation and performance of crosslinked microporous cassawa starch

    Institute of Scientific and Technical Information of China (English)

    吴思芸; 王继虎; 张燕萍; 于丹凤; 邵思盼; 李冬亮; 贺正果; 唐忠锋

    2013-01-01

    Crosslinked microporous starch was prepared with cassava starch as raw materials, phosphorus oxychloride as crosslinking agent,glucoamylase and alpha amylase as composite enzyme.The results showed that the dosages of starch content,crosslinking agent and composite enzyme,pH,reaction temperature and reaction time remarkable influenced the performance of crosslinked microporous starch. The optimum technological conditions were starch content 30% , crosslinking agent for 80μL, pH4.5, compound amylase amount of 2.0%, enzymatic hydrolysis temperature at 50℃ and enzymatic hydrolysis time of 12h.The structure and morphology of the crosslinked microporous starch were characterized by SEM,XRD and TGA.%以木薯淀粉为原料,三氯氧磷为交联剂,糖化酶与α-淀粉酶为复合酶,对交联微孔木薯淀粉的制备及其性能进行了研究.结果表明:交联淀粉乳浓度、交联剂的用量、复合酶用量、缓冲液pH、酶解温度和酶解时间对交联微孔淀粉性能影响较显著.当交联淀粉乳浓度为30%、交联剂用量为80μL、缓冲液pH4.5、复合酶用量2.0%、酶解温度50℃、酶解时间12h时,交联微孔淀粉具有较佳吸水率和吸油能力.通过SEM、XRD和TGA对交联微孔淀粉进行了测定与分析.

  17. Preparation and thermodynamics characterization of micro-porous TiC%TiC微孔陶瓷的制备及其热力学表征

    Institute of Scientific and Technical Information of China (English)

    罗勇; 田茂财; 杨莉

    2012-01-01

    Material thermodynamics is used to analyze the carburization of titanium alloy for the purpose of research on the formation mechanism of micro-porous TiC ceramics. And then TiC miero-porous ceramics are successfully synthesized on the surface of titanium alloys using se- quential carburization. Finally, the properties of micro-porous TiC ceramics are examined. It is found that the sequential carburization is thermodynamically feasible, and graphite is obtained after the carburization. It also reveals that the high hardness could provide excellent support to the titanium alloy substrate. The results show that compact micro-porous titanium carbide with a face-centred cubic structure has high hardness value of 16.1 GPa, which indicates that micro --porous TiC ceramics is a potential biomaterial due to its excellent protection of the titanium substrate.%为了研究TiC微孔陶瓷的形成机理,采用材料热力学分析了钛合金的渗碳工艺,采用分级渗碳法在钛合金表面制备出了TiC微孔陶瓷,并对微孔陶瓷进行了性能表征.研究后认为钛合金分级渗碳在热力学上可行,同时在分级渗碳中得到的是石墨碳;其硬度很高能够对钛合金形成很好的支撑作用.结果表明:面心立方结构的碳化钛微孔陶瓷的纳米硬度值达到了16.1GPa,将对钛合金基体起到很好的保护作用,是一种很有前途的生物材料.

  18. Preparation of Micro-pored Silicone Elastomer Through Radiation Crosslinking%辐射交联法制备微孔化硅橡胶的研究

    Institute of Scientific and Technical Information of China (English)

    高小铃; 古梅; 谢续兵; 黄玮

    2013-01-01

    The radiation crosslinking was adopted to prepare the micro-pored silicone elastomer,which was performed by vulcanization and foaming respectively.Radiation crosslinking is a new method to prepare micro-pored material with high performance by use of radiation technology.Silicon dioxide was used as filler,and silicone elastomer was vulcanized by electron beams,then the micro-pored material was made by heating method at a high temperature.The effects of absorbed dose and filler content on the performance and morphology were investigated.The structure and distribution of pores were observed by SEM.The results show that the micro-pored silicon elastomer can be prepared successfully by controlling the absorbed dose and filler content.It has a smooth surface similar to a rubber meanwhile the pores are round and unconnected to each other with the minimum size of 14 μm.And the good mechanical performance can be suitable for further uses.%采用辐射交联法制备微孔化硅橡胶材料,实现硫化与发泡分步进行,是探索射线技术用于制备高性能微孔材料的一种新方法.以二氧化硅为填料,以电子加速器为射线源辐照实现硅橡胶的硫化,再经高温发泡为微孔材料.主要研究辐照条件、填料含量等关键因素对硅橡胶性能与结构的影响,并用扫描电镜观察泡孔的形态结构.结果表明,通过控制吸收剂量和填料含量等条件,实现了硅橡胶材料微孔化.微孔化硅橡胶材料表面光滑,接近橡胶形态,而材料内部具有丰富的μm级小孔,孔壁完整,孔与孔间彼此不贯通,泡孔细小,胞体尺寸(平均)最小达14 μm,泡孔的均匀性好,其力学性能较好.

  19. The dehydrated copper silicate Na2[Cu2Si4O11]: a three-dimensional microporous framework with a linear Si—O—Si linkage

    OpenAIRE

    2008-01-01

    The structure of the title dehydrated copper silicate, disodium dicopper undecaoxide tetrasilicate, Na2(Cu2O11Si4), was determined by single-crystal X-ray diffraction from a non-merohedral twin. It exhibits an effective three-dimensional microporous framework with the major channels, in which the Na+ cations are placed, running along the a-axis direction and smaller channels observed along the b-axis direction. The structure is unusual in that it contains a symmetry-constrained Si—OR...

  20. Computer analysis of microporous structure by employing the LBET class models with various variants of the adsorption energy distribution in comparison to the classical equations.

    Science.gov (United States)

    Kwiatkowski, Mirosław

    2007-02-27

    The paper presents a properties study of the new LBET class models for heterogeneous multilayer adsorption and its applicability to analysis of microporous carbonaceous adsorbents in comparison to the selected classical equations. This paper shows that the LBET formulas give a good insight into the pore size distribution and dominant pore shape. Moreover, they provide more reliable evaluation of material surface area than the popular classical equations. This research constitutes a significant development and completion of the author's earlier works and provides a basis for the evaluation of reliability of parameters calculated for real systems.

  1. Use of fast multivariant identification of the parameters of adsorption systems to study the impact of activating agent on microporous structure formation during activation.

    Science.gov (United States)

    Kwiatkowski, Mirosław

    2009-12-01

    The possibility of using fast multivariant identification of adsorption system parameters to evaluate the influence of the activation conditions on the microporous structure of carbonaceous adsorbents was examined. The fitted models used in the procedure are based on a unique approach to the modeling of adsorption processes, which is a significant development of the conventional BET approach. This takes into account the occurrence of branched clusters and surface heterogeneity. The approach considers heterogeneity from the perspectives of both geometry and energy, and discusses geometrical and energy limitations of creating clusters and the adhesive forces in layers above the first one.

  2. A triptycene-based microporous organic polymer bearing tridentate ligands and its application in Suzuki-Miyaura cross-coupling reaction.

    Science.gov (United States)

    Wen, Qiang; Zhou, Tian-You; Zhao, Qiao-Ling; Fu, Jie; Ma, Zhi; Zhao, Xin

    2015-02-01

    A triptycene-based microporous organic polymer (MOP) in which 2,6-bis(benzimidazol-2-yl)pyridine (bbp) is incorporated as linkage and coordination site is designed and synthesized. Pd(II) ions are further immobilized in this MOP through the coordination interactions between Pd(II) ion and nitrogen atoms of bbp. The resulting material shows high stability and exhibits excellent heterogeneously catalytic activity for the Suzuki-Miyaura cross-coupling reaction. Its high efficiency can be maintained after being reused for a number of cycles.

  3. HCl-Catalyzed Polymerization of Benzoxazine and Chemical Transformations along Pyrolysis to Microporous Carbons in Advanced and Emerging Polybenzoxazine Science and Technology

    Science.gov (United States)

    2015-08-29

    materials (pore size < 2 nm), ranging from inorganic zeolites to metal oxide frameworks ( MOFs ), to crystalline covalent organic frameworks (COFs), to...and were tested for CO2 adsorption : meso/macro ! 33 porosity provides for near open-air diffusion and access to the entire microporous skeletal...framework [75], which should adsorb CO2. Indeed, adsorption isotherms at 0 oC up to a relative pressure of P/Po=0.03 (1 atm) show that both A- and H

  4. Study on the Gel-freezing Method Preparation Chinese Sweet Potato Microporous Starch%凝胶-冷冻法制备红薯微孔淀粉工艺的研究

    Institute of Scientific and Technical Information of China (English)

    傅新征; 许海基; 张仪秀

    2015-01-01

    以红薯淀粉为原材料制备红薯微孔淀粉,以红薯微孔淀粉的吸水率和吸油率为指标,探讨并优化凝胶–冷冻法制备红薯微孔淀粉的工艺参数。结果表明,制备红薯微孔淀粉的优化工艺参数为:红薯淀粉乳浓度100 g/L、糊化时间40 min、冷冻时间39 h、糊化温度90℃,此工艺下制备的红薯微孔淀粉吸水率为467.51%、吸油率为76.36%。%Chinese sweet potato starch was used as the raw materials to prepared Chinese sweet potato microporous starch. The water absorption rate and oil absorption rate of Chinese sweet potato microporous starch were used as indexes, discuss and optimize the process conditions of the gel-freezing method preparation Chinese sweet potato microporous starch. The results showed that the optimum prepara-tion process conditions of Chinese sweet potato microporous starch:Chinese sweet potato starch milk concentration 10g/100ml, gelatiniza-tion time 40min, freezing time 39h, gelatinization temperature 90℃. Under the condition, the water absorption rate of Chinese sweet potato microporous starch was 467.51%, and the oil absorption rate of Chinese sweet potato microporous starch was 76.36%.

  5. Structure and growth of polymeric niobia-silica mixed-oxide sols for microporous molecular sieving membranes: a SAXS study

    NARCIS (Netherlands)

    Boffa, V.; Castricum, H.L.; Garcia, R.; Schmuhl, R.; Petukhov, A.V.; Blank, D.H.A.; ten Elshof, J.E.

    2009-01-01

    Branched polymeric niobia-silica (NS) mixed-oxide sols with a Nb:Si molar ratio between 0.33 and 0.8 were made by acid-catalyzed sol-gel synthesis and characterized using small-angle X-ray scattering (SAXS) and dynamic light scattering (DLS). The growth rate of NS sols after addition of a niobium al

  6. Modular structure of a robust microporous MOF based on Cu2 paddle-wheels with high CO2 selectivity.

    Science.gov (United States)

    Seco, José M; Fairen-Jimenez, David; Calahorro, Antonio J; Méndez-Liñán, Laura; Pérez-Mendoza, Manuel; Casati, Nicola; Colacio, Enrique; Rodríguez-Diéguez, Antonio

    2013-12-14

    The synthesis of a new MOF with Cu2 paddle-wheels connected to glutarate and 1,3-bis(4-pyridyl)propane linkers has been explored. Experimental gas adsorption measurements reveal that the MOF is essentially non-porous to methane whereas it presents a type III isotherm upon CO2 adsorption, leading to high capacity and outstanding CO2 selectivity.

  7. Hybrid nanostructured microporous carbon-mesoporous carbon doped titanium dioxide/sulfur composite positive electrode materials for rechargeable lithium-sulfur batteries

    Science.gov (United States)

    Zegeye, Tilahun Awoke; Kuo, Chung-Feng Jeffrey; Wotango, Aselefech Sorsa; Pan, Chun-Jern; Chen, Hung-Ming; Haregewoin, Atetegeb Meazah; Cheng, Ju-Hsiang; Su, Wei-Nien; Hwang, Bing-Joe

    2016-08-01

    Herein, we design hybrid nanostructured microporous carbon-mesoporous carbon doped titanium dioxide/sulfur composite (MC-Meso C-doped TiO2/S) as a positive electrode material for lithium-sulfur batteries. The hybrid MC-Meso C-doped TiO2 host material is produced by a low-cost, hydrothermal and annealing process. The resulting conductive material shows dual microporous and mesoporous behavior which enhances the effective trapping of sulfur and polysulfides. The hybrid MC-Meso C-doped TiO2/S composite material possesses rutile TiO2 nanotube structure with successful carbon doping while sulfur is uniformly distributed in the hybrid MC-Meso C-doped TiO2 composite materials after the melt-infusion process. The electrochemical measurement of the hybrid material also shows improved cycle stability and rate performance with high sulfur loading (61.04%). The material delivers an initial discharge capacity of 802 mAh g-1 and maintains it at 578 mAh g-1 with a columbic efficiency greater than 97.1% after 140 cycles at 0.1 C. This improvement is thought to be attributed to the unique hybrid nanostructure of the MC-Meso C-doped TiO2 host and the good dispersion of sulfur in the narrow pores of the MC spheres and the mesoporous C-doped TiO2 support.

  8. Three-dimensional study of poly(lactic co-glycolic acid) micro-porous microspheres using hard X-ray nano-tomography.

    Science.gov (United States)

    Wang, Dajiang; Li, Na; Wang, Zhili; Gao, Kun; Zhang, Yongming; Luo, Yuyan; Wang, Shengxiang; Bao, Yuan; Shao, Qigang; Wu, Ziyu

    2014-09-01

    Poly(lactic co-glycolic acid) (PLGA) is widely used in diverse fields, especially in delivering biologically active proteins and drugs. For these applications, the knowledge of morphology and microstructure of PLGA micro-porous microspheres is of great importance since they strongly influence the drug delivering efficiency. In this study, micro-porous PLGA microspheres loaded by bovine serum albumin are investigated by using a full-field Zernike phase contrast transmission hard X-ray microscope. From three-dimensional reconstructions and segmentations, fundamental microstructural parameters such as size, shape, distribution and volume ratio among pores and proteins inside PLGA microspheres were obtained. These parameters are useful to understand the relationship between the internal microstructure and drug encapsulation, as well as the drug release efficiency of PLGA microspheres. The presented results demonstrate the capability of hard X-ray nano-tomography to characterize porous microspheres loaded with proteins and drugs, and also open a way to analyse, optimize and design new PLGA microspheres for specific applications.

  9. In vitro and in vivo study of microporous ceramics using MC3T3 cells, CAM assay and a pig animal model.

    Science.gov (United States)

    Tomco, Marek; Petrovova, Eva; Giretova, Maria; Almasiova, Viera; Holovska, Katarina; Cigankova, Viera; Jenca, Andrej; Jencova, Janka; Jenca, Andrej; Boldizar, Martin; Balazs, Kosa; Medvecky, Lubomir

    2017-09-01

    Bone tissue engineering combines biomaterials with biologically active factors and cells to hold promise for reconstructing craniofacial defects. In this study the biological activity of biphasic hydroxyapatite ceramics (HA; a bone substitute that is a mixture of hydroxyapatite and β-tricalcium phosphate in fixed ratios) was characterized (1) in vitro by assessing the growth of MC3T3 mouse osteoblast lineage cells, (2) in ovo by using the chick chorioallantoic membrane (CAM) assay and (3) in an in vivo pig animal model. Biocompatibility, bioactivity, bone formation and biomaterial degradation were detected microscopically and by radiology and histology. HA ceramics alone demonstrated great biocompatibility on the CAM as well as bioactivity by increased proliferation and alkaline phosphatase secretion of mouse osteoblasts. The in vivo implantation of HA ceramics with bone marrow mesenchymal stem cells (MMSCs) showed de novo intramembranous bone healing of critical-size bone defects in the right lateral side of pig mandibular bodies after 3 and 9 weeks post-implantation. Compared with the HA ceramics without MMSCs, the progress of bone formation was slower with less-developed features. This article highlights the clinical use of microporous biphasic HA ceramics despite the unusually shaped elongated micropores with a high length/width aspect ratio (up to 20) and absence of preferable macropores (>100 µm) in bone regenerative medicine.

  10. Water-dispersible Hollow Microporous Organic Network Spheres as Substrate for Electroless Deposition of Ultrafine Pd Nanoparticles with High Catalytic Activity and Recyclability.

    Science.gov (United States)

    Wang, Zhifang; Chang, Jing; Hu, Yuchen; Yu, Yifu; Guo, Yamei; Zhang, Bin

    2016-11-22

    Microporous organic networks (MONs) have been considered as an ideal substrate to stabilize active metal nanoparticles. However, the development of highly water-dispersible hollow MONs nanostructures which can serve as both the reducing agent and stabilizer is highly desirable but still challenging. Here we report a template-assisted method to synthesize hollow microporous organic network (H-MON) spheres using silica spheres as hard template and 1,3,5-triethynylbenzene as the building blocks through a Glaser coupling reaction. The obtained water-dispersible H-MON spheres bearing sp- and sp(2) -hybridized carbon atoms possess a highly conjugated electronic structure and show low reduction potential; thus, they can serve as a reducing agent and stabilizer for electroless deposition of highly dispersed Pd clusters to form a Pd/H-MON spherical hollow nanocomposite. Benefitting from their high porosity, large surface area, and excellent solution dispersibility, the as-prepared Pd/H-MON hollow nanocomposite exhibits a high catalytic performance and recyclability toward the reduction of 4-nitrophenol.

  11. A New Class of P(VdF-HFP-CeO2-LiClO4-Based Composite Microporous Membrane Electrolytes for Li-Ion Batteries

    Directory of Open Access Journals (Sweden)

    G. Vijayakumar

    2011-01-01

    Full Text Available Composite microporous membranes based on Poly (vinylidene fluoride–co-hexafluoro propylene P(VdF-co-HFP-CeO2 were prepared by phase inversion and preferential polymer dissolution process. It was then immersed in 1M LiClO4-EC/DMC (v/v=1:1 electrolyte solution to obtain their corresponding composite microporous membrane electrolytes. For comparison, composite membrane electrolytes were also prepared by conventional phase inversion method. The surface morphology of composite membranes obtained by both methods was examined by FE-SEM analysis, and their thermal behaviour was investigated by DSC analysis. It was observed that the preferential polymer dissolution composite membrane electrolytes (PDCMEs had better properties, such as higher porosity, electrolyte uptake (216 wt%, ionic conductivity (3.84 mS⋅cm−1 and good electrochemical stability (4.9 V, than the phase inversion composite membrane electrolytes (PICMEs. As a result, a cell fabricated with PDCME in between mesocarbon microbead (MCMB anode and LiCoO2 cathode had better cycling performance than a cell fabricated with PICME.

  12. Confined Amorphous Red Phosphorus in MOF-Derived N-Doped Microporous Carbon as a Superior Anode for Sodium-Ion Battery.

    Science.gov (United States)

    Li, Weihan; Hu, Shuhe; Luo, Xiangyu; Li, Zhongling; Sun, Xizhen; Li, Minsi; Liu, Fanfan; Yu, Yan

    2017-04-01

    Red phosphorus (P) has attracted intense attention as promising anode material for high-energy density sodium-ion batteries (NIBs), owing to its high sodium storage theoretical capacity (2595 mAh g(-1) ). Nevertheless, natural insulating property and large volume variation of red P during cycling result in extremely low electrochemical activity, leading to poor electrochemical performance. Herein, the authors demonstrate a rational strategy to improve sodium storage performance of red P by confining nanosized amorphous red P into zeolitic imidazolate framework-8 (ZIF-8) -derived nitrogen-doped microporous carbon matrix (denoted as P@N-MPC). When used as anode for NIBs, the P@N-MPC composite displays a high reversible specific capacity of ≈600 mAh g(-1) at 0.15 A g(-1) and improved rate capacity (≈450 mAh g(-1) at 1 A g(-1) after 1000 cycles with an extremely low capacity fading rate of 0.02% per cycle). The superior sodium storage performance of the P@N-MPC is mainly attributed to the novel structure. The N-doped porous carbon with sub-1 nm micropore facilitates the rapid diffusion of organic electrolyte ions and improves the conductivity of the encapsulated red P. Furthermore, the porous carbon matrix can buffer the volume change of red P during repeat sodiation/desodiation process, keeping the structure intact after long cycle life. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  13. 锥面-微孔组合端面机械密封性能%Performance of mechanical face seals with both surface micropores and convergent coning

    Institute of Scientific and Technical Information of China (English)

    彭旭东; 刘鑫; 孟祥铠; 白少先; 盛颂恩

    2011-01-01

    在收敛锥面密封和多孔端面机械密封研究的基础上,提出了锥面-微孔组合端面新型机械密封,建立了该组合密封端面液膜压力控制的理论模型并采用有限元法求解,获得了端面液膜压力分布.在给定径向微孔比、周向微孔比和微孔深径比等微孔几何结构参数的条件下,分析了端面锥度、锥面宽度比、扇形微孔区的径向位置等组合密封几何结构参数在低压和高压工况下对密封性能的影响规律,研究了组合密封的开启特性,指出了锥面与扇形微孔区不同组合方式的特点及各自的使用范围.结果表明:在低压工况下,收敛锥面能提高机械密封的开启特性,扇形微孔区开设在端面高压侧能获得较好的密封性能;在高压工况下,微孔的动压效应能提高机械密封的稳定性,扇形微孔区设在低压侧能获得较好的密封性能;当端面特征几何结构参数选取为:锥度1.5~2.5,锥面宽度比0.2~0.6,内坝区宽度比0.1~0.3时,密封可获得优良的综合性能.%Based on the study of mechanical face seals with convergent coning or surface micropores, a new type of mechanical seal with both surface micropores and convergent coning was presented. The definitions of face geometric parameters of such a new type of seal were made. Such parameters included the radial taper of the coned face, the width ratio of the coned face to the seal face, and the width ratio of sealing dam to seal face. A theoretical analysis model for controlling fluid film pressure between the two faces of such a seal was set up and was solved with the finite element method. The fluid film pressure profile between the faces was then obtained. Analyses were made about the effect of face geometric parameters on seal performance, such as opening force, leakage and axial film stiffness under low pressure or high pressure of the sealed medium, in which the radial length ratio of micropore zone to face width

  14. Synthesis and gas permeation properties of a novel thermally-rearranged polybenzoxazole made from an intrinsically microporous hydroxyl-functionalized triptycene-based polyimide precursor

    KAUST Repository

    Alghunaimi, Fahd

    2017-06-06

    A hydroxyl-functionalized triptycene-based polyimide of intrinsic microporosity (TDA1-APAF) was converted to a polybenzoxazole (PBO) by heat treatment at 460 °C under nitrogen atmosphere. TDA1-APAF treated for 15 min (TR 460) resulted in a PBO conversion of 95% based on a theoretical weight loss of 11.7 wt% of the polyimide precursor. The BET surface area of the TR 460 (680 m2 g−1) was significantly higher than that of the TDA1-APAF polyimide (260 m2 g−1) as determined by nitrogen adsorption at −196 °C. Heating TDA1-APAF for 30 min (TRC 460) resulted in a weight loss of 13.5 wt%, indicating full conversion to PBO and partial main-chain degradation. The TR 460 membrane displayed excellent O2 permeability of 311 Barrer coupled with an O2/N2 selectivity of 5.4 and CO2 permeability of 1328 Barrer with a CO2/CH4 selectivity of 27. Interestingly, physical aging over 150 days resulted in enhanced O2/N2 selectivity of 6.3 with an O2 permeability of 185 Barrer. The novel triptycene-based TR 460 PBO outperformed all previously reported APAF-polyimide-based PBOs with gas permeation performance close to recently reported polymers located on the 2015 O2/N2 upper bound. Based on this study, thermally-rearranged membranes from hydroxyl-functionalized triptycene-based polyimides are promising candidate membrane materials for air separation, specifically in applications where space and weight of membrane systems are of utmost importance such as nitrogen production for inert atmospheres in fuel lines and tanks on aircrafts and off-shore oil- or natural gas platforms. Mixed-gas permeation experiments also demonstrated good performance of the TR 460 membrane for natural gas sweetening with a CO2 permeability of ∼1000 Barrer and CO2/CH4 selectivity of 22 at a typical CO2 wellhead partial pressure of 10 bar.

  15. Investigation of Graphene Oxide on Modification of Polyurethane Microporous Membrane%氧化石墨烯对聚氨酯微孔膜的改性研究

    Institute of Scientific and Technical Information of China (English)

    王乾乾; 王全杰

    2012-01-01

    采用改进的Hummers法制备氧化石墨(GO),超声剥离得到氧化石墨烯(GOs),借助TEM、AFM、FT—IR和XRD对样品的形貌结构进行了表证,结果表明制得了富有合氧基团(C=O、-0H、-c00H、c-0-c等)的具有较好稳定性的GOs。通过湿法成膜制备了GOs改性的聚氨酯微孔膜,探讨了加入的GOs含量对复合聚氨酯PU微孔膜相关性能的影响,结果表明:当加入质量分数0.1%的GOs时,Pu微孔膜的力学性能提高最明显;随着GOs含量的增加,复合膜体积电阻系数较空白样先增大后减小,在加入1.0%的GOs时,体积电阻系数开始低于空白样的即导电性有所提高;复合膜的吸湿率、孔隙率和透湿量,随着GOs添加量的增加均呈现增大的趋势,说明GOs的加入对PU微孔膜通透性能的改善亦有显著影响。%The graphite oxide(GO) was prepared through the improved Hummers method, then the graphene oxide(COs) was obtained via ultrasonic stripping. The representations of TEM, AFM, FT - IR and XRD on the morphology and structure of the sam- pies, indicated that the stable graphene oxide was obtained owning their bearing various oxygen functional groups ( C = O, C - OH, -COOH and C -O- C). Then the wet polyurethane microporous membrane modified with the graphene oxide was prepared. The effects of additive amounts of GOs on the mechanical properties, electrical behavior and permeability of as - prepared polyurethane microporous membranes were investigated by means of tensile test and megger equipment. The results showed that the mechanical property of polyurethane microporous membrane containing O. lwt. % GOs was significantly improved; with increasing the content of GOs, at the initial stage of relatively lower volume of addition, the volume resistivity of the prepared polyurethane samples first in- creased and then showed a decreasing trend. The conductivity of the polyurethane microporous

  16. Potential application of microporous structured poly(vinylidene fluoride-hexafluoropropylene)/poly(ethylene terephthalate) composite nonwoven separators to high-voltage and high-power lithium-ion batteries

    Energy Technology Data Exchange (ETDEWEB)

    Jeong, Hyun-Seok; Choi, Eun-Sun [Department of Chemical Engineering, Kangwon National University, Chuncheon, Kangwondo, 200-701 (Korea, Republic of); Kim, Jong Hun [Batteries R and D, LG Chem, Yusong-gu, Daejon, 305-380 (Korea, Republic of); Lee, Sang-Young, E-mail: syleek@kangwon.ac.kr [Department of Chemical Engineering, Kangwon National University, Chuncheon, Kangwondo, 200-701 (Korea, Republic of)

    2011-05-30

    Highlights: > Microporous-structured PVdF-HFP/PET composite nonwoven separators for Li-batteries. > Well-developed microporous structure and liquid electrolyte wettability. > Provision of facile ion transport and suppressed growth of cell impedance. > Superior cell performance at high-voltages/high-current densities. - Abstract: We demonstrate potential application of a new composite non-woven separator, which is comprised of a phase inversion-controlled, microporous polyvinylidene fluoride-hexafluoropropylene (PVdF-HFP) gel polymer electrolyte and a polyethylene terephthalate (PET) non-woven support, to high-voltage and high-power lithium-ion batteries. In comparison to a commercialized polyethylene (PE) separator, the composite non-woven separator exhibits distinct improvements in microporous structure and liquid electrolyte wettability. Based on the understanding of the composite non-woven separator, cell performances of the separator at challenging charge/discharge conditions are investigated and discussed in terms of ion transport of the separator and AC impedance of the cell. The aforementioned advantageous features of the composite non-woven separator play a key role in providing facile ion transport and suppressing growth of cell impedance during cycling, which in turn contribute to superior cell performances at harsh charge/discharge conditions such as high voltages and high current densities.

  17. Organic Synthesis

    OpenAIRE

    Romea, Pedro

    2014-01-01

    Organic Synthesis is a one-semester course of the fourth year of the Chemistry Degree at the Universitat de Barcelona. This course covers the most important transformations in Organic Chemistry, including a short introduction to the Retrosynthetic Analysis. The aim is to provide a solid knowledge of the main reactions and their mechanism, which could later be improved during Master studies.

  18. Ultrafast Li-storage of MoS2 nanosheets grown on metal-organic framework-derived microporous nitrogen-doped carbon dodecahedrons

    Science.gov (United States)

    Shao, Jie; Gao, Tian; Qu, Qunting; Shi, Qiang; Zuo, Zhichen; Zheng, Honghe

    2016-08-01

    The nanocomposites of MoS2 nanosheets and microporous nitrogen-doped carbon dodecahedron (MNCD) are prepared through the pyrolysis of metal-organic framework (MOF) and subsequent growth of MoS2. The porous and active surface of MNCDs enables uniform growth of ultrathin MoS2 nanosheets. When the MNCD@MoS2 composite is used as the anode material of Li-ion batteries, a reversible capacity of 915 mAh g-1 can be obtained even at the extremely high current density of 10 A g-1. The ultrafast charge/discharge ability of MNCD@MoS2 can be attributed to its unique core-shell structure with the inner MNCDs serving as the reservoir of Li-ions and transport media of electrons.

  19. Large pore volume mesoporous copper particles and scaffold microporous carbon material obtained from an inorganic-organic nanohybrid material, copper-succinate-layered hydroxide.

    Science.gov (United States)

    Ghotbi, Mohammad Yeganeh; Bagheri, Narjes; Sadrnezhaad, S K

    2011-10-01

    Copper-succinate-layered hydroxide (CSLH), a new nanohybrid material, was synthesized as an inorganic-organic nanohybrid, in which organic moiety was intercalated between the layers of a single cation layered material, copper hydroxide nitrate. Microporous scaffold carbon material was obtained by thermal decomposition of the nanohybrid at 500 °C under argon atmosphere followed by acid washing process. Furthermore, the heat-treated product of the nanohybrid at 600 °C was ultrafine mesoporous metallic copper particles. The results of this study confirmed the great potential of CSLH to produce the carbon material with large surface area (580 m(2)/g) and high pore volume copper powder (2.04 cm(3)/g).

  20. Micro-PIXE and micro-RBS characterization of micropores in porous silicon prepared using microwave-assisted hydrofluoric acid etching.

    Science.gov (United States)

    Ahmad, Muthanna; Grime, Geoffrey W

    2013-04-01

    Porous silicon (PS) has been prepared using a microwave-assisted hydrofluoric acid (HF) etching method from a silicon wafer pre-implanted with 5 MeV Cu ions. The use of microbeam proton-induced X-ray emission (micro-PIXE) and microbeam Rutherford backscattering techniques reveals for the first time the capability of these techniques for studying the formation of micropores. The porous structures observed from micro-PIXE imaging results are compared to scanning electron microscope images. It was observed that the implanted copper accumulates in the same location as the pores and that at high implanted dose the pores form large-scale patterns of lines and concentric circles. This is the first work demonstrating the use of microwave-assisted HF etching in the formation of PS.