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Sample records for surfactant intercalated montmorillonite

  1. Preparation and Characterization of Montmorillonite Intercalation Compounds with Quaternary Ammonium Surfactant: Adsorption Effect of Zearalenone

    Directory of Open Access Journals (Sweden)

    Yujin Li

    2014-01-01

    Full Text Available Montmorillonite (Mt was used as the original material to prepare intercalation compounds with quaternary ammonium surfactant (QAS. The adsorption of zearalenone (ZEA onto Mt and organomodified Mt was investigated in vitro. Effects of QAS in binding ZEA were studied. By the method of intercalation with dioctadecylmethylbenzylammonium chloride (DOMBAC, the sample exhibited the highest adsorption rate of ZEA (93.2% which was much higher than that of Mt (10.5%. Several methods were adopted to characterize samples, including XRD, TG/DSC, N2 adsorption/desorption, and FTIR. Adsorption isotherm parameters were obtained from Langmuir and Freundlich and the adsorption data fitted better to Langmuir. All results indicate that organomodified Mt has great potential to be a high-performance material to control ZEA contamination.

  2. Intercalation of Amido Cationic Drug with Montmorillonite

    Institute of Scientific and Technical Information of China (English)

    ZHENG Junping; WANG Hongyan; ZHUANG Hong; XI Lifei; YAO Kangde

    2007-01-01

    The intercalation of drug molecules with montmorillonit (MMT) using Acyclovir (ACV) as the model drug was focused on. The optimum conditions were studied based on orthogonal design, such as intercalation time and temperature. The intercalation composites were characterized by X-ray diffraction (XRD), Fourier transformed infrared (FT-IR), and thermogravimetric analysis (TGA). The experimental results reveal that ACV is successfully intercalated into the interlayers of MMT. The in vitro release experiments reveal that ACV is released from MMT steadily and pH dependent

  3. Preparation and Properties of Phenolic Resin/Montmorillonite Intercalation Nanocomposites

    Institute of Scientific and Technical Information of China (English)

    YU Jian-ying; WEI Lian-qi; CAO Xian-kun

    2003-01-01

    Phenolic resin/ montmorillonite intercalation composites were prepared by using the methods of pressing intercalation and melt intercalation. Properties and structure of the composites were investigated by using XRD , TG and test of softening point. It is indicated that both the pressing intercalation and melt intercalation can be used to prepare the phenolic resin/organo-montmorillonite intercalation nanocomposites. Compared with phenolic resin, the intercalation nanocomposites have better heat-resistance, higher decomposition temperatures and less thermal weight-loss. However , these two intercalation methods have different effects on the softening point of the intercalation nanocomposites . Pressing intercalation almost does not affect the softening point of the intercalation nanocomposites, while melt intercalation signifwantly increases the softening point of the intercalation nanocomposites ,probably due to the chemical actions happening in the process of melt intercalation.

  4. Modification of Nanocomposites by Melting Intercalation of Polypropylene in Montmorillonite

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    The polypropylene was modified by ultraviolet irradiation.The polypropylene-montmorillonite nanocomposites were prepared by direct melting intercalation of polypropylene powders.The structure of polypropylene,the polyproprlene irradiated, montmorillinote and polypropylene-montmorillonite composites were studied by XRD, IR and DSC. The results show that the PP molecules can are oxidized during ultraviolet irradiation,melt polypropylene can intercalate into montmorillonite layer.As a result,the layered distance (d001) of montmorillonite increases, and the melt absorption peak of polypropylene in layer is eliminated.

  5. Morphology and Structure of Amino-fatty Acid Intercalated Montmorillonite

    Science.gov (United States)

    Reyes, Larry; Sumera, Florentino

    2015-04-01

    Natural clays and its modified forms have been studied for their wide range of applications, including polymer-layered silicate, catalysts and adsorbents. For nanocomposite production, montmorillonite (MMT) clays are often modified with organic surfactants to favor its intermixing with the polymer matrix. In the present study, Na+-montmorillonite (Na+-MMT) was subjected to organo-modification with a protonated 12-aminolauric acid (12-ALA). The amount of amino fatty acid surfactants loaded was 25, 50, 100 and 200% the cation exchange capacity (CEC) of Na+-MMT (25CEC-AMMT, 50CEC-AMMT, 100CEC-AMMT and 200CEC-AMMT). Fatty acid-derived surfactants are an attractive resource of intercalating agents for clays due to their renewability and abundance. X-ray diffraction (XRD) and Fourier Transform Infrared Spectroscopy (FTIR) were performed to determine the occurrence of intercalation of 12-ALA and their molecular structure in the clay's silicates. XRD analysis revealed that the interlayer spacing between the alumino-silicate layers increased from 1.25 nm to 1.82 nm with increasing ALA content. The amino fatty acid chains were considered to be in a flat monolayer structure at low surfactant loading, and a bilayered to a pseudotrilayered structure at high surfactant loading. On the other hand, FTIR revealed that the alkyl chains adopt a gauche conformation, indicating their disordered state based on their CH2symmetric and asymmetric vibrations. Thermogravimetric analyses (TGA) allows the determination of the moisture and organic content in clays. Here, TGA revealed that the surfactant in the clay was thermally stable, with Td ranging from 353° C to 417° C. The difference in the melting behavior of the pristine amino fatty acids and confined fatty acids in the interlayer galleries of the clay were evaluated by Differential Scanning Calorimerty (DSC). The melting temperatures (Tm) of the amino fatty acid in the clay were initially found to be higher than those of the free

  6. Melt-intercalation studies of polystyrene ionomers in pristine montmorillonite

    Science.gov (United States)

    Bhiwankar, Nikhil N.

    The main objective of this study was to examine the use of ionomers, specifically alkylamine-neutralized sulfonated polystyrene (SPS) for promoting intercalation into unmodified sodium montmorillonite clay and its use as a compatabilizer for intercalating another polymer into unmodified silicate clay. The processing parameters and chemical structure of polymers which led to the formation of partially intercalated/exfoliated morphologies were investigated. Melt-intercalated polymer layered silicate nanocomposites (PLSNs) are made by mixing polymers and organically modified silicates by the application of shear forces. However, the thermal decomposition temperatures of the organic modifications are usually comparable to the processing temperatures of most of the polymers. Hence, in this work modification of the polymer, rather than the clay, for promoting melt intercalation, specifically the introduction of alkyl ammonium salt groups along the polymer chain was considered. In this study the effects of viscosity, shear rates and mixing times on the morphology of nanocomposites were investigated. The effect of ionic content in the polymer chain of SPS in the batch mixtures of SPS and PS was researched. We also compared the effect on the extent of intercalation in these silicate clay galleries as a function of size of the counter-ions by varying the alkyl chain length and as a function of basicity of these counter-ions by varying the number of alkyl substituents that are attached on the N of the amine. The melt mixing of pristine Na-Mmt with alkyl ammonium and quaternary ammonium salts of SPS ionomers, resulted in an increase in the silicate gallery spacing consistent with intercalation. Mixtures of the ionomer with PS exhibited similar gallery spacing increases, indicating that the ionomer is an effective compatibilizing agent for the melt-intercalation of hydrophobic polymers into the clay. The extent of intercalation was independent of the melt processing conditions

  7. Preparation of a cationic azobenzene dye-montmorillonite intercalation compound and its photochemical behavior

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    Montmorillonite/cationic azobenzene dye (GTL) intercalation compounds were prepared by the conventional ion exchange method. As compared with that of pure GTL, the thermal stability of the intercalated GTL was greatly enhanced, and the absorption band corresponding to azobenzene group in intercalated GTL shifted towards a longer wavelength by 55 nm, which could be ascribed to the strong conjugation of GTL supramolecular order structure (J cluster) confined in a nanoscale space of montmorillonite interlayer gallery. The microstructures of the resulting intercalation compounds could be successfully controlled by varying the amount of dye loaded as evidenced by the basal spacing of the intercalation compounds. The intercalated azo dye in the montmorillonite interlayer space exhibited reversible trans-to-cis photoisomerization and thermal cis-to-trans reaction. FTIR proved the successful intercalation of GTL into the silicate layer.

  8. Preparation and Photochemical Behavior of a Cationic Azobenzene Dye-Montmorillonite Intercalation Compound

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    Montmorillonite/cationic azobenzene dye(p-(δ-triethylammoniobutoxy)-p'-methyl-azobenzene bromide) intercalation compounds were prepared by the conventional ion exchange method. As compared with that of pure cationic azo-dye, the thermal stability of the intercalated dye was greatly enhanced, and the absorption band corresponding to azobenzene group in intercalated dye shifted towards longer wave length by 38 nm. This could be ascribed to the strong conjugation of cationic azo-dye supramolecular order structure(J cluster) confined in a nanoscale space of montmorillonite interlayer gallery. UV/vis spectra data show that the intercalated azo dye in the montmorillonite interlayer space exhibited reversible trans-to-cis photoisomerization and daylight cis-to-trans back reaction. FTIR indicates the successful intercalation of cationic azo-dye into the montmorillonite interlayer.

  9. Degradation of surfactant-modified montmorillonites in HCl

    Energy Technology Data Exchange (ETDEWEB)

    Madejova, Jana, E-mail: jana.madejova@savba.sk [Institute of Inorganic Chemistry, SAS, Dubravska cesta 9, SK-845 36 Bratislava (Slovakia); Palkova, Helena, E-mail: helena.palkova@savba.sk [Institute of Inorganic Chemistry, SAS, Dubravska cesta 9, SK-845 36 Bratislava (Slovakia); Jankovic, Lubos, E-mail: lubos.jankovic@savba.sk [Institute of Inorganic Chemistry, SAS, Dubravska cesta 9, SK-845 36 Bratislava (Slovakia)

    2012-06-15

    The effect of surfactant size on the extent of montmorillonites decomposition in HCl was investigated. Na-SAz montmorillonite and tetraalkylammonium salts of alkyl-chains length increasing from methyl- Me{sub 4}N to pentyl- Pe{sub 4}N were used for organo-montmorillonites preparation. Decreasing intensity of d{sub 001} diffraction proved destruction of montmorillonite structure connected with gradual surfactant release. A shift of the SiO stretching band to 1097 cm{sup -1} confirmed formation of amorphous silica phase. A new band near 7315 cm{sup -1} corresponding to SiOH overtone revealed creation of protonated silica. This band was observed in the spectra of all acid-treated samples, also in those with minor decomposition of the structure. The size of the cations significantly affected decomposition of montmorillonites in HCl. The less stable were Na-SAz and Me{sub 4}N-SAz in which the content of octahedral atoms dropped to {approx}5% of their original values upon 8 h treatments. Et{sub 4}N-SAz and Pr{sub 4}N-SAz were slightly more resistant mainly at short times. Bu{sub 4}N-SAz and Pe{sub 4}N-SAz showed the least structural modifications, only 50% and 35% of octahedral atoms, respectively, were released into solution within 8 h treatments. This observation proves that bulky alkylammonium cations covering the inner and outer surfaces of montmorillonite prevent effectively the access of protons to the layers protecting the mineral from degradation in the acid. - Highlights: Black-Right-Pointing-Pointer Hybrid materials were prepared from montmorillonite and alkylammonium cations with short alkyl chains. Black-Right-Pointing-Pointer The effect of surfactant on organo-montmorillonites dissolution in HCl was studied. Black-Right-Pointing-Pointer With increasing size of cation the extent of montmorillonite decomposition decreased. Black-Right-Pointing-Pointer Bulky surfactants prevent the access of protons to the layers and thus protect montmorillonite from

  10. Study on intercalation of ionic liquid into montmorillonite and its property evaluation

    Energy Technology Data Exchange (ETDEWEB)

    Takahashi, Chisato; Shirai, Takashi [Advanced Ceramics Research Laboratory, Nagoya Institute of Technology, 3-101-1, Honmachi, Tajimi, Gifu 507-0033 (Japan); Fuji, Masayoshi, E-mail: fuji@nitech.ac.jp [Advanced Ceramics Research Laboratory, Nagoya Institute of Technology, 3-101-1, Honmachi, Tajimi, Gifu 507-0033 (Japan)

    2012-08-15

    Present study report fabrication of a solid-liquid intercalated compound using montmorillonite and ionic liquid [IL; 1-Butyl-3-methylimidazolium tetrafluoroborate; ([BMIM][BF{sub 4}])]. The intercalation of IL into the interlayer of montmorillonite was revealed by swelling behavior measured by X-ray diffraction (XRD) and cation exchange capacity (CEC). The crystal swelling structure of intercalation compound was further evidenced by transmission electron microscope (TEM). From these results, the arrangement of [BMIM]{sup +} ions (cationic part of IL) into the unit layer were proposed. Furthermore, the montmorillonite showed electrical conductivity with the aid of IL. This demonstrates a successful attempt to fabricate a solid-liquid state nano-structure compound as possible transparent electrically conducting thin film. -- Highlights: Black-Right-Pointing-Pointer Direct intercalation of ionic liquid into the montmorillonite was studied. Black-Right-Pointing-Pointer The crystal swelling structure in liquid state was successfully characterized by TEM. Black-Right-Pointing-Pointer We proposed the atomic arrangement of intercalated compound using ionic liquid. Black-Right-Pointing-Pointer Ionic liquid is useful for fabricating an intercalated compound with electrical-conductivity.

  11. Synthesis and characterization of montmorillonite clay intercalated with molecular magnetic compounds

    Energy Technology Data Exchange (ETDEWEB)

    Martins, Marcel G.; Martins, Daniel O.T.A.; Carvalho, Beatriz L.C. de [Instituto de Química, Universidade Federal Fluminense, Niterói, RJ 24.020–150 (Brazil); Mercante, Luiza A. [Laboratório Nacional de Nanotecnologia para o Agronegócio (LNNA), Embrapa Instrumentação, São Carlos, SP 13560 970 (Brazil); Soriano, Stéphane [Instituto de Física, Universidade Federal Fluminense, Niterói, RJ 24.210 346 (Brazil); Andruh, Marius [Inorganic Chemistry Laboratory, Faculty of Chemistry, University of Bucharest, Str. Dumbrava Rosie nr. 23, Bucharest (Romania); Vieira, Méri D., E-mail: gqimeri@vm.uff.br [Instituto de Química, Universidade Federal Fluminense, Niterói, RJ 24.020–150 (Brazil); Vaz, Maria G.F., E-mail: mariavaz@vm.uff.br [Instituto de Química, Universidade Federal Fluminense, Niterói, RJ 24.020–150 (Brazil)

    2015-08-15

    In this work montmorillonite (MMT) clay, whose matrix was modified with an ammonium salt (hexadecyltrimethylammonium bromide – CTAB), was employed as an inorganic host for the intercalation of three different molecular magnetic compounds through ion exchange: a nitronyl nitroxide derivative 2-[4-(N-ethyl)-pyridinium]-4,4,5,5-tetramethylimidazoline-1-oxyl-3-oxide (p-EtRad{sup +}) and two binuclear coordination compounds, [Ni(valpn)Ln]{sup 3+}, where H{sub 2}valpn stands for 1,3-propanediyl-bis(2-iminomethylene-6-methoxy-phenol), and Ln=Gd{sup III}; Dy{sup III}. The pristine MMT and the intercalated materials were characterized by X-ray powder diffraction (XRD), infrared spectroscopy (IR), scanning electron microscopy (SEM), thermogravimetric analysis (TGA) and magnetic measurements. The X-ray diffraction data analysis showed an increase of the interlamellar space of the intercalated MMT, indicating the intercalation of the magnetic compounds. Furthermore, the magnetic properties of the hybrid compounds were investigated, showing similar behavior as the pure magnetic guest species. - Graphical abstract: Montmorillonite clay was employed as inorganic host for the intercalation of three different molecular magnetic compounds through ion exchange - Highlights: • Montmorillonite was employed as a host material. • Three molecular magnetic compounds were intercalated through ion exchange. • The compounds were successful intercalated maintaining the layered structure. • The hybrid materials exhibited similar magnetic behavior as the pure magnetic guest.

  12. Controlled Release of Agrochemicals Intercalated into Montmorillonite Interlayer Space

    Directory of Open Access Journals (Sweden)

    Harrison Wanyika

    2014-01-01

    Full Text Available Periodic application of agrochemicals has led to high cost of production and serious environmental pollution. In this study, the ability of montmorillonite (MMT clay to act as a controlled release carrier for model agrochemical molecules has been investigated. Urea was loaded into MMT by a simple immersion technique while loading of metalaxyl was achieved by a rotary evaporation method. The successful incorporation of the agrochemicals into the interlayer space of MMT was confirmed by several techniques, such as, significant expansion of the interlayer space, reduction of Barrett-Joyner-Halenda (BJH pore volumes and Brunauer-Emmett-Teller (BET surface areas, and appearance of urea and metalaxyl characteristic bands on the Fourier-transform infrared spectra of the urea loaded montmorillonite (UMMT and metalaxyl loaded montmorillonite (RMMT complexes. Controlled release of the trapped molecules from the matrix was done in water and in the soil. The results reveal slow and sustained release behaviour for UMMT for a period of 10 days in soil. For a period of 30 days, MMT delayed the release of metalaxyl in soil by more than 6 times. It is evident that MMT could be used to improve the efficiency of urea and metalaxyl delivery in the soil.

  13. Controlled Release of Agrochemicals Intercalated into Montmorillonite Interlayer Space

    Science.gov (United States)

    2014-01-01

    Periodic application of agrochemicals has led to high cost of production and serious environmental pollution. In this study, the ability of montmorillonite (MMT) clay to act as a controlled release carrier for model agrochemical molecules has been investigated. Urea was loaded into MMT by a simple immersion technique while loading of metalaxyl was achieved by a rotary evaporation method. The successful incorporation of the agrochemicals into the interlayer space of MMT was confirmed by several techniques, such as, significant expansion of the interlayer space, reduction of Barrett-Joyner-Halenda (BJH) pore volumes and Brunauer-Emmett-Teller (BET) surface areas, and appearance of urea and metalaxyl characteristic bands on the Fourier-transform infrared spectra of the urea loaded montmorillonite (UMMT) and metalaxyl loaded montmorillonite (RMMT) complexes. Controlled release of the trapped molecules from the matrix was done in water and in the soil. The results reveal slow and sustained release behaviour for UMMT for a period of 10 days in soil. For a period of 30 days, MMT delayed the release of metalaxyl in soil by more than 6 times. It is evident that MMT could be used to improve the efficiency of urea and metalaxyl delivery in the soil. PMID:24696655

  14. In Situ Molecular Spectroscopic Evidence for CO2 Intercalation into Montmorillonite in Supercritical Carbon Dioxide

    Energy Technology Data Exchange (ETDEWEB)

    Loring, John S.; Schaef, Herbert T.; Turcu, Romulus VF; Thompson, Christopher J.; Miller, Quin RS; Martin, Paul F.; Hu, Jian Z.; Hoyt, David W.; Qafoku, Odeta; Ilton, Eugene S.; Felmy, Andrew R.; Rosso, Kevin M.

    2012-04-25

    The interaction of anhydrous supercritical CO2 (scCO2) with both kaolinite and ~1W (i.e. close to but less than one layer of hydration) calcium-saturated montmorillonite was investigated under conditions relevant to geologic carbon sequestration (50 °C and 90 bar). The CO2 molecular environment was probed in situ using a combination of three novel high-pressure techniques: X-ray diffraction, magic angle spinning nuclear magnetic resonance spectroscopy and attenuated total reflection infrared spectroscopy. We report the first direct evidence that the expansion of montmorillonite under scCO2 conditions is due to CO2 migration into the interlayer. Intercalated CO2 molecules are rotationally constrained and do not appear to react with waters to form bicarbonate or carbonic acid. In contrast, CO2 does not intercalate into kaolinite. The findings show that predicting the seal integrity of caprock will have complex dependence on clay mineralogy and hydration state.

  15. In situ molecular spectroscopic evidence for CO2 intercalation into montmorillonite in supercritical carbon dioxide.

    Science.gov (United States)

    Loring, John S; Schaef, Herbert T; Turcu, Romulus V F; Thompson, Christopher J; Miller, Quin R S; Martin, Paul F; Hu, Jianzhi; Hoyt, David W; Qafoku, Odeta; Ilton, Eugene S; Felmy, Andrew R; Rosso, Kevin M

    2012-05-08

    The interaction of anhydrous supercritical CO(2) (scCO(2)) with both kaolinite and ~1W (i.e., close to but less than one layer of hydration) calcium-saturated montmorillonite was investigated under conditions relevant to geologic carbon sequestration (50 °C and 90 bar). The CO(2) molecular environment was probed in situ using a combination of three novel high-pressure techniques: X-ray diffraction, magic angle spinning nuclear magnetic resonance spectroscopy, and attenuated total reflection infrared spectroscopy. We report the first direct evidence that the expansion of montmorillonite under scCO(2) conditions is due to CO(2) migration into the interlayer. Intercalated CO(2) molecules are rotationally constrained and do not appear to react with waters to form bicarbonate or carbonic acid. In contrast, CO(2) does not intercalate into kaolinite. The findings show that predicting the seal integrity of caprock will have complex dependence on clay mineralogy and hydration state.

  16. Confinement of a nonionic surfactant membrane within a montmorillonite as a new way to prepare organoclay materials

    Energy Technology Data Exchange (ETDEWEB)

    Guegan, Regis, E-mail: regis.guegan@univ-orleans.fr [Universite d' Orleans (France); Giovanela, Marcelo [Universidade de Caxias do Sul (UCS), RS (Brazil)

    2016-11-15

    The aim of this study was to prepare and characterize a hybrid layered material (organoclay) with a Na-montmorillonite and the triethylene glycol mono-n-decyl ether (C{sub 10}E{sub 3} ) nonionic surfactant which forms a lamellar phase at room temperature. The synthesized organoclay was characterized by complementary techniques (Fourier transform infrared spectroscopy and X-ray diffraction). Experiments in conjunction with electron density analysis showed that a bilayer or membrane of C{sub 10}E{sub 3} was intercalated within the interlayer space of a naturally exchanged Na-montmorillonite. The intercalation of a bilayer of C{sub 10}E{sub 3} in a clay mineral offers new perspectives for the manufacturing of nanomaterials. While showing a hydrophobic surface and a large interlayer space value, the resulting organoclay preserves the compensating cations within the interlayer space allowing one to perform ion exchanges, making easier the intercalation of further organic molecules of important size with functional properties or for environmental purposes. (author)

  17. Hydrocarbon chain conformation in an intercalated surfactant monolayer and bilayer

    Indian Academy of Sciences (India)

    N V Venkataraman; S Vasudevan

    2001-10-01

    Cetyl trimethyl ammonium (CTA) ions have been confined within galleries of layered CdPS3 at two different grafting densities. Low grafting densities are obtained on direct intercalation of CTA ions into CdPS3 to give Cd0.93PS3(CTA)0.14. Intercalation occurs with a lattice expansion of 4.8 Å with the interlamellar surfactant ion lying flat forming a monolayer. Intercalation at higher grafting densities was effected by a two-step ion-exchange process to give Cd0.83PS3(CTA)0.34, with a lattice expansion of 26.5 Å. At higher grafting densities the interlamellar surfactant ions adopt a tilted bilayer structure. 13C NMR and orientation-dependent IR vibrational spectroscopy on single crystals have been used to probe the conformation and orientation of the methylene ‘tail’ of the intercalated surfactant in the two phases. In the monolayer phase, the confined methylene chain adopts an essentially all-trans conformation with most of the trans chain aligned parallel to the gallery walls. On lowering the temperature, molecular plane aligns parallel, so that the methylene chain lies flat, rigid and aligned to the confining surface. In the bilayer phase, most bonds in the methylene chain are in trans conformation. It is possible to identify specific conformational sequences containing a gauche bond, in the interior and termini of the intercalated methylene. These high energy conformers disappear on cooling leaving all fifteen methylene units of the intercalated cetyl trimethyl ammonium ion in trans conformational registry at 40 K.

  18. Preparation of the Thermoplastic Starch/Montmorillonite Nanocomposites by Melt-intercalation

    Institute of Scientific and Technical Information of China (English)

    Ming Fu HUANG; Jiu Gao YU; Xiao Fei MA

    2005-01-01

    In this paper, the conception of melt-intercalation was introduced into the natural polymer field, and the thermoplastic starch/ethanolamine-activated montmorillonite (TPS/EMMT)nanocomposites were prepared by extruding the composites of EMMT and TPS, plasticized with ethanolamine/formamide. Wide angle X-ray diffraction (WAXD) and transmission electron microscope (TEM) revealed that TPS was intercalated into the layers of EMMT successfully and formed the intercalation nanocomposites with EMMT. When EMMT content was wt. 10%, the mechanical testing indicated that the tensile stress of the nanocomposites reached 9.69 MPa, and the tensile strain reached 74.07%, Youngs modulus increased from the 47.23 MPa of TPS to 184.11after they had been stored at RH25% for 14 days.

  19. ORGANIC-INORGANIC HYBRIDS PREPARED FROM ALKYL PHOSPHONIUM SALTS INTERCALATED MONTMORILLONITES

    Directory of Open Access Journals (Sweden)

    SAHELI GANGULY

    2012-12-01

    Full Text Available Present investigation is focused on systematic and detailed characterization of alkyl phosphonium intercalated montmorillonite (MMT. The objective of the work is to provide a better understanding of the specific changes in properties of the hybrid material with changes in structure of incoming organic cations. In the present work, Na-MMT was intercalated with phosphonium salts of two different cationic head compositions namely alkyl triphenyl and alkyl tributyl groups. Length of alkyl chain was also varied. Resultant organic-inorganic hybrids were characterized by X-ray diffraction (XRD, Transmission electron microscopy (TEM, Thermogravimetry (TG and Fourier transformed infrared spectroscopy (FTIR. Effective volume occupied by the cationic heads influenced interlayer arrangements. Intercalated MMT with two different cationic heads behaved differently in relation to thermal decomposition patterns. Possible explanation was given based on hybridization of bonds. Van der Waals attachment of alkyl chains influenced the interlayer stacking and organic loading. Attempts were made to correlate the changes in properties of intercalated MMT with the structural aspects of incoming organic cations.

  20. DISPERSION AND TENSILE BEHAVIOR OF POLYPROPYLENE/MONTMORILLONITE NANOCOMPOSITES PRODUCED VIA MELT INTERCALATION

    Institute of Scientific and Technical Information of China (English)

    Qin Zhang; Ke Wang; Y. Men; Qiang Fu

    2003-01-01

    Most of the articles on polymer nanocomposites focus on the importance of chemistry used to modify the surface of the clay, usually montmorillonite (MMT), and characterization of the nano-scale structure obtained. The role and importance of processing were also discussed recently. However, few papers concerning the correlation between morphology of MMT and mechanical properties were published. In order to understand the tensile behavior of PP/Montmorillonite(MMT) nanocomposites better, and to further improve the reinforcement efficiency, we first prepared the PP nanocomposites via direct melt intercalation using conventional twin-screw extrusion. The dispersion and tensile property of the composites were then investigated by SEM, XRD, TEM and a video-controlled tensile set-up. The macroscopic and microscopic dispersion of MMT in PP matrix was verified by XRD and TEM, combined with SEM. The tensile properties were obtained by video-controlled tensile set-up, which gives true stress-strain curve. It was found that a partly intercalated and partly exfoliated structure (also called incomplete exfoliation) existed in the system. Though the tensile strength of PPnanocomposites is not much improved in engineering stress-strain curves, more than 20% increase of true stress was found ina true stress-strain experiment at high true strain, which indicates that only oriented silicate layers can have a big effect ontensile properties. Not only orientation of silicate platelets but also the degree of exfoliation is a key factor to determine thereinforcement efficiency. The reinforcement efficiency of MMT has been discussed based on the "continuum" Halpin-Tsaiequations. A good agreement was found between experimental data and theoretical prediction by changing N value (numberofplatelets per stack) which corresponding to different state of the dispersion of MMT in PP matrix.

  1. Molecular Simulation Models of Carbon Dioxide Intercalation in Hydrated Sodium Montmorillonite

    Energy Technology Data Exchange (ETDEWEB)

    Myshakin, Evgeniy [National Energy Technology Lab. (NETL), Pittsburgh, PA, (United States); Saidi, Wissam [Univ. of Pittsburgh, PA (United States); Romanov, Vyacheslav [National Energy Technology Lab. (NETL), Pittsburgh, PA, (United States); Cygan, Randall [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Jordan, Kenneth [National Energy Technology Lab. (NETL), Pittsburgh, PA, (United States); Univ. of Pittsburgh, PA (United States); Guthrie, George [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2016-11-22

    In this study, classical molecular dynamics simulations and density functional theory (DFT)-based molecular dynamics are used to elucidate the process of CO2 intercalation into hydrated Na-montmorillonite at P-T conditions relevant to geological formations suitable for CO2 storage. Of particular interest are the structural and transport properties of interlayer species after CO2 intercalation. The conducted simulations allowed the research team to quantify expansion/contraction of smectite as a function of CO2 and H2O compositions. The resulting swelling curves can be used to gauge the amount of stored CO2, compare it to the experiment, and estimate changes in geomechanical properties of the storage formation. The obtained results showed that the infrared signal of the asymmetric stretch vibration of CO2 molecule is extremely sensitive to the solvent environment. The extent of the frequency shift relative to the gas-phase value can be used to probe hydration level in the interlayer with intercalated CO2. Interaction of supercritical CO2 with brine in deep geological formations promotes an increase of hydrophobicity of clay surfaces. As a result of wettability alteration, estimated diffusion constants of CO2 and H2O increase with the increased CO2 load; this can contribute to faster migration of CO2 throughout the formation.

  2. Adsorption and intercalation of anionic surfactants onto layered double hydroxides—XRD study

    Indian Academy of Sciences (India)

    R Anbarasan; W D Lee; S S Im

    2005-04-01

    Layered double hydroxides (LDH) with brucite like structure was modified with various anionic surfactants containing sulfonate, carboxyl, phosphonate and sulfate end group through ion-exchange method. XRD reports indicated that the sulfonate group containing surfactants led to an adsorption process whereas the sulfate, carboxyl and phosphonate group containing surfactant led to an intercalation process. This can be evidenced from the change in basal spacing of LDH. The presence of anionic surfactants in the LDH was supported by FTIR spectroscopy. The FTIR spectrum indicated that complete removal of carbonate anion from the inter layer space of LDH is very difficult. The phosphonate intercalated HT showed less thermal stability than pristine LDH.

  3. Uptake of permanganate from aqueous environment by surfactant modified montmorillonite batch and fixed bed studies

    Indian Academy of Sciences (India)

    N Mahadevaiah; B Vijayakumar; K Hemalatha; B S Jai Prakash

    2011-12-01

    Organo-clay was prepared by incorporating different amounts (in terms of CEC, ranging from 134–840 mg of quaternary ammonium cation (QACs) such as hexadecytrimethylammonium bromide ([C19H42N]Br) into the montmorillonite clay. Prepared organo-clays are characterized by CHN analyser and XRD to measure the amount of elemental content and interlayer spacing of surfactant modified clay. The batch experiments of sorption of permanganate from aqueous media by organo-clays was studied at different acidic strengths (pH 1–7). The experimental results show that the rate and amount of adsorption of permanganate was higher at lower pH compared to raw montmorillonite. Laboratory fixed bed experiments were conducted to evaluate the breakthrough time and nature of breakthrough curves. The shape of the breakthrough curves shows that the initial cationic surfactant loadings at 1.0 CEC of the clay is enough to enter the permanganate ions in to the interlamellar region of the surfactant modified smectile clays. These fixed bed studies were also applied to quantify the effect of bed-depth and breakthrough time during the uptake of permanganate. Calculation of thermodynamic parameters shows that the sorption of permanganate is spontaneous and follows the first order kinetics.

  4. Silicone fluids intercalation into montmorillonite clay. SAXS/WAXD morphological evaluation; Intercalacao de fluidos de silicona em argila montmorillonita. Avaliacao morfologica por SAXS/WAXD

    Energy Technology Data Exchange (ETDEWEB)

    Kaneko, Manuela L.Q.A.; Yoshida, Inez Valeria P. [Universidade Estadual de Campinas (UNICAMP), SP (Brazil). Inst. de Quimica]. E-mail: manuela_andrade@yahoo.com; valeria@iqm.unicamp.br; Torriani, Iris [Universidade Estadual de Campinas (UNICAMP), SP (Brazil). Inst. de Fisica Gleb Wataglin; Laboratorio Nacional de Luz Sincrotron (LNLS), Campinas, SP (Brazil)

    2005-07-01

    The morphological aspects related to the intercalation of three different silicone fluids into montmorillonite clay (MMT) were investigated by small and wide angle X-ray scattering (SAXS/WAXD). The MMT dispersions prepared with the different silicone fluids showed an intercalated morphology. The extent of intercalation into the gallery, swelling and orientation of the platelets varied according to the nature of the silicone fluid. Particle thickness of 78 and 63 Angstrom for some of the silicone/MMT dispersions was calculated from the X-ray scattering profiles. (author)

  5. Sodium montmorillonite/amine-containing drugs complexes: new insights on intercalated drugs arrangement into layered carrier material.

    Directory of Open Access Journals (Sweden)

    Murilo L Bello

    Full Text Available Layered drug delivery carriers are current targets of nanotechnology studies since they are able to accommodate pharmacologically active substances and are effective at modulating drug release. Sodium montmorillonite (Na-MMT is a clay that has suitable properties for developing new pharmaceutical materials due to its high degree of surface area and high capacity for cation exchange. Therefore Na-MMT is a versatile material for the preparation of new drug delivery systems, especially for slow release of protonable drugs. Herein, we describe the intercalation of several amine-containing drugs with Na-MMT so we can derive a better understanding of how these drugs molecules interact with and distribute throughout the Na-MMT interlayer space. Therefore, for this purpose nine sodium montmorillonite/amine-containing drugs complexes (Na-MMT/drug were prepared and characterized. In addition, the physicochemical properties of the drugs molecules in combination with different experimental conditions were assessed to determine how these factors influenced experimental outcomes (e.g. increase of the interlayer spacing versus drugs arrangement and orientation. We also performed a molecular modeling study of these amine-containing drugs associated with different Na-MMT/drug complex models to analyze the orientation and arrangement of the drugs molecules in the complexes studied. Six amine-containing drugs (rivastigmine, doxazosin, 5-fluorouracil, chlorhexidine, dapsone, nystatin were found to successfully intercalate Na-MMT. These findings provide important insights on the interlayer aspect of the molecular systems formed and may contribute to produce more efficient drug delivery nanosystems.

  6. Preparation and Characterization of Polyurethane Nanocomposites Using Vietnamese Montmorillonite Modified by Polyol Surfactants

    Directory of Open Access Journals (Sweden)

    C. N. Ha Thuc

    2014-01-01

    Full Text Available This study focuses on the preparation of thermoplastic polyurethane (TPU nanocomposite using Vietnamese montmorillonite (MMT as the reinforced phase. The MMT was previously modified by intercalating polyethylene oxide (PEO and polyvinyl alcohol (PVA molecules between the clay layers. X-ray diffraction (XRD results of organoclays revealed that galleries of MMT were increased to 18.2 Å and 27 Å after their intercalation with PEO and PVA, respectively. Thermoplastic polyurethane (TPU nanocomposites composed of 1, 3, 5, and 7%wt organoclays were synthesized. The result of XRD and transmission electron microscopic (TEM analyses implied that the PEO modified MMT was well dispersed, at 3%wt, in polyurethane matrix. Fourier Transform Infrared Spectroscopic (FTIR has confirmed this result by showing the hydrogenous interaction between the urethane linkage and OH group on the surface of silicate layer. Thermogravimetric (TG showed that the organoclay samples also presented improved thermal stabilities. In addition, the effects of the organoclays on mechanical performance and water absorption of the PU nanocomposite were also investigated.

  7. XRD study of intercalation in statically annealed composites of ethylene copolymers and organically modified montmorillonites. 2. One-tailed organoclays

    Directory of Open Access Journals (Sweden)

    Sara Filippi

    2014-01-01

    Full Text Available Ethylene copolymers with different polar comonomers, such as vinyl acetate, methyl acrylate, glycidyl methacrylate, and maleic anhydride, were used for the preparation of polymer/clay nanocomposites by statically annealing their mechanical mixtures with different commercial or home-made organically modified montmorillonites containing only one long alkyl tail. The nanostructure of the products was monitored by X-ray diffraction, and the dispersion of the silicate particles within the polymer matrix was qualitatively evaluated through microscopic analyses. The effect of the preparation conditions on the structure and the morphology of the composites was also addressed through the characterization of selected samples with similar composition prepared by melt compounding. In agreement with the findings reported in a previous paper for the composites filled with two-tailed organoclays, intercalation of the copolymer chains within the tighter galleries of the one-tailed clays occurs easily, independent of the application of a mechanical stress. However, the shear-driven break-up of the intercalated clay particles into smaller platelets (exfoliation seems more hindered. A collapse of the organoclay interlayer spacing was only observed clearly for a commercial one-tailed organoclay – Cloisite® 30B – whereas the same effect was almost negligible for a home-made organoclay with similar structure.

  8. Methotrexate intercalated layered double hydroxides with the mediation of surfactants: Mechanism exploration and bioassay study

    Energy Technology Data Exchange (ETDEWEB)

    Dai, Chao-Fan; Tian, De-Ying; Li, Shu-Ping, E-mail: lishuping@njnu.edu.cn; Li, Xiao-Dong

    2015-12-01

    Methotrexatum intercalated layered double hydroxides (MTX/LDHs) hybrids were synthesized by the co-precipitation method and three kinds of nonionic surfactants with different hydrocarbon chain lengths were used. The resulting hybrids were then characterized by X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy and transmission electron microscopy (TEM). XRD and FTIR investigations manifest the successful intercalation of MTX anions into the interlayer of LDHs. TEM graphs indicate that the morphology of the hybrids changes with the variation of the chain length of the surfactants, i.e., the particles synthesized using polyethylene glycol (PEG-7) present regular disc morphology with good monodispersity, while samples with the mediation of alkyl polyglycoside (APG-14) are heavily aggregated and samples with the addition of polyvinylpyrrolidone (PVP-10) exhibit irregular branches. Furthermore, the release and bioassay experiments show that monodisperse MTX/LDHs present good controlled-release and are more efficient in the suppression of the tumor cells. - Highlights: • Surfactants could be used to modify the dispersing state of MTX/LDHs hybrids. • Surfactants have great effect on the morphology of MTX/LDHs hybrids. • MTX/LDHs with good monodisperse degree are more efficient in the suppression of the tumor cells.

  9. Efficient inhibition of heavy metal release from mine tailings against acid rain exposure by triethylenetetramine intercalated montmorillonite (TETA-Mt).

    Science.gov (United States)

    Gong, Beini; Wu, Pingxiao; Huang, Zhujian; Li, Yuanyuan; Yang, Shanshan; Dang, Zhi; Ruan, Bo; Kang, Chunxi

    2016-11-15

    The potential application of triethylenetetramine intercalated montmorillonite (TETA-Mt) in mine tailings treatment and AMD (acid mine drainage) remediation was investigated with batch experiments. The structural and morphological characteristics of TETA-Mt were analyzed with XRD, FTIR, DTG-TG and SEM. The inhibition efficiencies of TETA-Mt against heavy metal release from mine tailings when exposed to acid rain leaching was examined and compared with that of triethylenetetramine (TETA) and Mt. Results showed that the overall inhibition by TETA-Mt surpassed that by TETA or Mt for various heavy metal ions over an acid rain pH range of 3-5.6 and a temperature range of 25-40°C. When mine tailings were exposed to acid rain of pH 4.8 (the average rain pH of the mining site where the mine tailings were from), TETA-Mt achieved an inhibition efficiency of over 90% for Cu(2+), Zn(2+), Cd(2+) and Mn(2+) release, and 70% for Pb(2+) at 25°C. It was shown that TETA-Mt has a strong buffering capacity. Moreover, TETA-Mt was able to adsorb heavy metal ions and the adsorption process was fast, suggesting that coordination was mainly responsible. These results showed the potential of TETA-Mt in AMD mitigation, especially in acid rain affected mining area.

  10. Synthesis of an organic–inorganic hybrid material by solid state intercalation of 2-mercaptopyridine into Na-, Al(III)- and Co(II)-montmorillonite

    Indian Academy of Sciences (India)

    I Bekri-Abbes; E Srasra

    2006-06-01

    The preparation of an organic–inorganic hybrid material by solid state intercalation of 2-merca-ptopyridine (2Mpy) into Na-, Co(II)- and Al(III)-montmorillonite has been studied using a variety of techniques. The extension of 001 from XRD proves that the intercalation of 2-mercaptopyridine into Na-, Co(II)- and Al(III)-mont occurs at ambient temperature in 5 mn. When the intercalated samples were heated at different temperatures, we found that the 001 gave different values. For instance, for intercalated Al(III)- and Co(II)-, 001 remained unchanged for a temperature under 500°C. However, for intercalated Na-mont, it shifted to 14 Å for a temperature of 300°C, the washing of different samples with a methanol solution shifted the 001 of intercalated Na-mont to 14 Å. However, for intercalated Al(III) and Co(II), it did not change. This proves that in the case of Na-mont, the molecules of 2-mercaptopyridine interact with the clay through hydrogen bindings and physical interactions. However, for Al(III) and Co(II), it forms coordination linking and physical interaction. 13C NMR and FTIR spectroscopy have been employed for the characterization of the intercalation compounds. Tautomeric equilibrium between thiol and thione species of 2-mercaptopyridine must be taken into account to explain the arrangement of molecular aggregates and their particular orientation in the interlayer space. The isotherm of adsorption–desorption of nitrogen and topographic AFM images prove that intercalation of 2Mpy is accompanied by a total blockage of clay porosity and an increase in roughness.

  11. Synthesis and surfactant modification of clinoptilolite and montmorillonite for the removal of nitrate and preparation of slow release nitrogen fertilizer.

    Science.gov (United States)

    Bhardwaj, Deepesh; Sharma, Monika; Sharma, Pankaj; Tomar, Radha

    2012-08-15

    This article introduces the synthesis of clinoptilolite and montmorillonite, and their surfactant modification by using solutions of hexadecyltrimethylammonium bromide (CH(3)(CH(2))(15)N(Br)(CH(3))(3), HDTMAB) and dioctadecyldimethylammonium bromide ((CH(3)(CH(2))(17))(2)N(Br)(CH(3))(2), DODMAB). The feasibility of using surfactant modified silicates (SMSs) as a potential adsorbent for nitrate and for slow release of nutrient has been investigated. Adsorption isotherms of NO(3)(-) on SMSs have been measured at aqueous concentration of 160-280 mg L(-1). The SMSs show much higher adsorption capacity than the unmodified materials as determined by Langmuir adsorption isotherm. The surfactant modification and increased surfactant loading concentration enhance the nitrate anion retaining capacity of silicates (montmorillonite (16.05 mg g(-1))clinoptilolite (30.58 mg g(-1))clinoptilolite (75.19 mg g(-1))clinoptilolite (125.00 mg g(-1))). The adsorption data fitted well with the Langmuir and Freundlich isotherms. The slow nutrient release studies have been performed by thin layers-funnel analytical test and soil column percolating system. The obtained results indicate that SMSs are very good adsorbent for NO(3)(-) and a slow release of nitrogen is achievable as it releases NO(3)(-) still after 15-20 days of leaching study.

  12. Design of Wood/Montmorillonite (MMT) Intercalation NanocompositeCollege of Material Science and Technology, Beijing Forestry University, Beijing 100083, P.R.China

    Institute of Scientific and Technical Information of China (English)

    Lü Wenhua; Zhao Guangjie

    2004-01-01

    Studying new wood composites through nano science and technology (NSC) will develop new compounding theory of wood, and accelerate the combination of new technology, wood science, material science and other disciplines. The compounding of wood and inorganic MMT on nanoscale molecular level has high potential to greatly improve the mechanical properties, fire retardance, abrasion resistance, decay resistance, dimensional stability and other properties of wood. Based on the great achievements of polymer/montmorillonite (MMT) nanocomposites, this paper reviewed nano intercalation compounding methods (i.e. in-situ intercalative polymerization and direct polymer intercalation), and discussed the structure, properties and modification of montmorillonite (MMT). According to the main chemical components and particular structure of wood, the authors discussed the liquefaction and plasticization of wood, compared the dissolvability and meltability between wood and polymer, and then systematically put forward the basic idea, technological processes and schematic diagram to prepare wood/MMT nanocomposites (WMNC). The key technology to prepare WMNC is either to introduce delaminated MMT nanolayers into wood with the help of some intermediate polymers, or to obtain liquefied wood or plasticized wood from the complicated natural composite. It is applicable and effective to realize wood/MMT nanoscale compounding with the help of proper intercalation agent and medium polymer through the proposed "one-step" or "two-step" impregnating processes.

  13. Effective and Selective Trapping of Volatile Organic Sulfur Derivatives by Montmorillonite Intercalated with a μ-oxo Fe(III)-Phenanthroline Complex.

    Science.gov (United States)

    Bernini, Fabrizio; Castellini, Elena; Malferrari, Daniele; Castro, German Rafael; Sainz Díaz, Claro Ignacio; Brigatti, Maria Franca; Borsari, Marco

    2017-01-11

    The μ-oxo Fe(III)-phenanthroline complex [(OH2)3(Phen)FeOFe(Phen) (OH2)3](+4) intercalated in montmorillonite provides a stable hybrid material. In this study, the ability and efficiency of this material to immobilize thiols in gas phase, acting as a trap at the solid-gas interface, were investigated. Aliphatic thiols containing both hydrophilic and hydrophobic end groups were chosen to test the selectivity of this gas trap. DR-UV-vis, IR, elemental analysis, thermal analysis and evolved gas mass spectrometry, X-ray powder diffraction, and X-ray absorption spectroscopy techniques were employed to characterize the hybrid material before and after thiol exposure and to provide information on the entrapping process. Thiol immobilization is very large, up to 21% w/w for heptanethiol. In addition, evidence was obtained that immobilization occurs through the formation of a covalent bond between the iron of the complex and the sulfur of the thiol. This provides an immobilization process characterized by a higher stability with respect to the methods based on physi-adsorption. Thiol immobilization resulted thermally reversible at least for 20 adsorption/desorption cycles. Unlike standard desulfurization processes like hydrotreating and catalytic oxidation which work at high temperatures and pressures, the present system is able to efficiently trap thiols at room temperature and pressure, thus saving energy. Furthermore, we found that the selectivity of thiol immobilization can be tuned acting on the amount of complex intercalated in montmorillonite. In particular, montmorillonite semisaturated with the complex captures both hydrophobic and hydrophilic thiols, while the saturated montmorillonite shows a strong selectivity toward the hydrophobic molecules.

  14. Effect of the intercalated cation-exchanged on the properties of nanocomposites prepared by 2-aminobenzene sulfonic acid with aniline and montmorillonite

    Energy Technology Data Exchange (ETDEWEB)

    Toumi, I. [Laboratoire de Chimie Organique, Macromoleculaire et des Materiaux, Universite de Mascara, Bp 763 Mascara 29000 (Algeria); Benyoucef, A., E-mail: ghani29000@yahoo.fr [Laboratoire de Chimie Organique, Macromoleculaire et des Materiaux, Universite de Mascara, Bp 763 Mascara 29000 (Algeria); Yahiaoui, A. [Laboratoire de Chimie Organique, Macromoleculaire et des Materiaux, Universite de Mascara, Bp 763 Mascara 29000 (Algeria); Quijada, C. [Departamento de Ingenieria Textil y Papelera, Universidad Politecnica de Valencia, Pza Ferrandiz i Carbonel, E-03801 Alcoy, Alicante (Spain); Morallon, E. [Departamento de Quimica Fisica e Instituto Universitario de Materiales, Universidad de Alicante, Apartado 99, E-03080 Alicante (Spain)

    2013-02-25

    Polymer/montmorillonite nanocomposites were prepared. Intercalation of 2-aminobenzene sulfonic acid with aniline monomers into montmorillonite modified by cation was followed by subsequent oxidative polymerization of monomers in the interlayer spacing. The clay was prepared by cation exchange process between sodium cation in (M-Na) and copper cation (M-Cu). XRD analyses show the manifestation of a basal spacing (d-spacing) for M-Cu changes depending on the inorganic cation and the polymer intercalated in the M-Cu structure. TGA analyses reveal that polymer/M-Cu composites is less stable than M-Cu. The conductivity of the composites is found to be 10{sup 3} times higher than that for M-Cu. The microscopic examinations including TEM picture of the nanocomposite demonstrated an entirely different and more compatible morphology. Remarkable differences in the properties of the polymers have also been observed by UV-Vis and FTIR, suggesting that the polymer produced with presence of aniline has a higher degree of branching. The electrochemical behavior of the polymers extracted from the nanocomposites has been studied by cyclic voltammetry which indicates the electroactive effect of nanocomposite gradually increased with aniline in the polymer chain.

  15. VERUCLAY – a new type of photo-adsorbent active in the visible light range: modification of montmorillonite surface with organic surfactant

    Science.gov (United States)

    Montmorillonite K10 was treated with VeruSOL-3, a biodegradable and food-grade surfactant mixture of coconut oil, castor oil and citrus extracts, to manufacture a benign catalytic adsorbent that is active in the visible light. Veruclay was characterized by SEM, XRD, TGA, UVDRS, a...

  16. Comparison between the removal of phenol and catechol by modified montmorillonite with two novel hydroxyl-containing Gemini surfactants

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Yuening; Gao, Manglai, E-mail: mlgao@cup.edu.cn; Gu, Zheng; Luo, Zhongxin; Ye, Yage; Lu, Laifu

    2014-02-01

    Highlights: • Organo-clays were prepared by two novel hydroxyl-containing Gemini surfactants. • The kinetics and thermodynamics of the novel organo-clays were studied. • The hydroxyl group of organo-clays can increase the adsorption capacity. • BHHP-Mt was proved to be a high-efficiency adsorbent to remove phenols. - Abstract: Na-montmorillonites were modified with two novel hydroxyl-containing Gemini surfactants, 1,3-bis(hexadecyldimethylammonio)-2-hydroxypropane dichloride (BHHP) and 1,3-bis(octyldimethylammonio)-2-hydroxypropane dichloride (BOHP), via ion-exchange reaction in this study. The modified samples were characterized by X-ray diffraction (XRD) and Fourier Transform Infrared (FT-IR) spectroscopy. Phenol and catechol were removed from aqueous solution by these two kinds of organo-montmorillonites in a batch system. Important parameters have been investigated, which affect the adsorption efficiency, such as the amount of modifier, temperature, pH and contact time. The adsorption kinetics of phenol and catechol were discussed using pseudo-first-order, pseudo-second-order and intra-particle diffusion model. It indicated that the experimental data fitted very well with the pseudo-second-order kinetic model, and the equilibrium adsorption data was proved in good agreement with the Langmuir isotherm. The result also showed the adsorption capacity of catechol was higher than that of phenol in the same conditions, which might result from the extra hydroxyl in the structure of catechol. Thermodynamic quantities such as Gibbs free energy (ΔG°), the enthalpy (ΔH°), and the entropy change of sorption (ΔS°) were also determined. These parameters suggested the adsorption of phenol was a spontaneous and exothermic process, while the sorption of catechol was endothermic.

  17. Response surface analysis of structural, mechanical, and permeability properties of polyethylene/Na+-montmorillonite composites, prepared by slurry-fed melt intercalation

    Directory of Open Access Journals (Sweden)

    S. I. S. Shahabadi

    2012-08-01

    Full Text Available Samples were produced by injecting Na+-montmorillonite (Na+-MMT slurry into a co-rotating twin-screw extruder. Na+-MMT was modified inside the extruder, in an in-situ process, and blended with the LDPE/LLDPE in melt state. Three different types of alkyl ammonium salt (ALAMS were used as modifier to study the effect of chemical composition and chain length of ALAMS on the dispersion of nanoparticles. Also, the effect of nanoclay content on structural, mechanical, and permeability properties of the samples was investigated. To translate the data into intelligible trends, response surface method was utilized to analyze the effects of the factors on the results. Moreover, transmission electron microscopy was implemented to observe the dispersion of nanoclay platelets. The results suggested that the chain length of ALAMS dramatically affects its ability to modify nanoclay platelets. What is more, while nanoclay increase deteriorates nanoparticles dispersion, it brings about better mechanical and gas barrier properties. The improvement in the properties was higher than those of nanocomposites prepared by conventional method. By studying the effects of feeding rate on nanoclay dispersion, we proved that unlike conventional melt intercalation, water-assisted melt intercalation is controlled by diffusion rather than shear stress. In the end, we proposed a mechanism for this process.

  18. Adsorption of dimeric surfactants in lamellar silicates

    Energy Technology Data Exchange (ETDEWEB)

    Balcerzak, Mateusz; Pietralik, Zuzanna [Department of Macromolecular Physics, Faculty of Physics, A. Mickiewicz University, Umultowska 85, 61-614 Poznań (Poland); Domka, Ludwik [Department of Metalorganic Chemistry, Faculty of Chemistry, A. Mickiewicz University, Grunwaldzka 6, 60-780 Poznań (Poland); Skrzypczak, Andrzej [Institute of Chemical Technology, Poznań University of Technology, Berdychowo 4, 60-965 Poznań (Poland); Kozak, Maciej, E-mail: mkozak@amu.edu.pl [Department of Macromolecular Physics, Faculty of Physics, A. Mickiewicz University, Umultowska 85, 61-614 Poznań (Poland)

    2015-12-01

    Highlights: • The intercalation of dimeric surfactants changed the morphology of MMT samples. • XRD indicated structures formed by surfactant molecules in interlayer space. • The four-step thermal decomposition of dimeric surfactant, confirms intercalation. - Abstract: The adsorption of different types of cationic surfactants in lamellar silicates changes their surface character from hydrophilic to hydrophobic. This study was undertaken to obtain lamellar silicates modified by a series of novel dimeric (gemini) surfactants of different length alkyl chains and to characterise these organophilised materials. Synthetic sodium montmorillonite SOMASIF® ME 100 (M) and enriched bentonite of natural origin (Nanoclay – hydrophilic bentonite®) were organophilised with dimeric (gemini) surfactants (1,1′-(1,4-butanediyl)bis(alkoxymethyl)imidazolium dichlorides). As a result of surfactant molecule adsorption in interlamellar space, the d-spacing (d{sub 001}) increased from 0.97 nm (for the anhydrous structure) to 2.04 nm. A Fourier transform infrared spectroscopy (FTIR) analysis of the modified systems reveals bands assigned to the stretching vibrations of the CH{sub 2} and CH{sub 3} groups and the scissoring vibrations of the NH group from the structure of the dimeric surfactants. Thermogravimetric (TG) and derivative thermogravimetric (DTG) studies imply a four-stage process of surfactant decomposition. Scanning electron microscopy (SEM) images provide information on the influence of dimeric surfactant intercalation into the silicate structures. Particles of the modified systems show a tendency toward the formation of irregularly shaped agglomerates.

  19. Simultaneous adsorption of Cd²⁺ and BPA on amphoteric surfactant activated montmorillonite.

    Science.gov (United States)

    Liu, Chongmin; Wu, Pingxiao; Zhu, Yajie; Tran, Lytuong

    2016-02-01

    The study mainly investigated the simultaneous adsorption of bisphenol A (BPA) and Cd(2+) from aqueous solution on octadecane-betaine modified montmorillonite (BS-Mt). The characteristics of the obtained materials were analyzed by X-ray diffraction (XRD), Fourier-transform infrared (FTIR), Specific surface area (BET) and Scanning electron microscopy/Energy disperse spectroscopy (SEM/EDS), confirming that BS-18 was successfully introduced into Mt. Also, factors including initial solution pH, initial Cd(2+)/BPA concentration, contact time and adsorbent dosage on the adsorption processes were shown to be crucial for Cd(2+) adsorption, whereas had negligible effects on BPA adsorption. In this study, we found that pseudo-second-order model fitted well with the adsorption kinetic studies for both Cd(2+) and BPA with an equilibrium time of 24 h. The Cd(2+) and BPA adsorption isotherm could be well described by Freundlich model and Langmuir model, respectively. On the basis of kinetic models, the maximum adsorption capacity of Cd(2+) in aqueous solution was slightly enhanced after modification, indicating that Cd(2+) adsorption on BS-Mt was mainly attributed to direct electrostatic attraction and the chelate reaction, while the dramatic enhancement of maximum adsorption capacity for BPA was due to the hydrophobic interaction.

  20. PREPARATION AND CHARACTERISATION OF HYDROPHOBIC AND CATIONIC MONTMORILLONITE

    Institute of Scientific and Technical Information of China (English)

    W. Liu; Y. Ni; H. Xiao

    2004-01-01

    Hydrophilic and cationic montmorillonite is desirable for pitch control in the pulp and paper industry. In this paper, polyaminoamide - epichlorohydrin (PAE)modified montmorillonite was prepared. The modified montmorillonite was characterized using X-ray diffraction, FTIR and thermal gravimetric analysis. The amount of PAE intercalated and cationic charge densities of the modified montmorillonite were determined. Finally, it was found that both the solution and melt-intercalated samples with different charge densities exhibited strong interactions with dispersed colloidal rosin acid.

  1. 戊二醛交联型骨胶/MMT复合物的性能研究%Study on Performance of Montmorillonite Intercalated by Bone Glue Modified by Glutaraldehyde

    Institute of Scientific and Technical Information of China (English)

    苏秀霞; 杨玉娜; 王培霖; 景洁

    2012-01-01

    将骨胶(BG)经戊二醛交联改性后,插层到蒙脱土(MMT)中,得到了交联型骨胶/MMT插层复合物。对骨胶插层的影响因素及改性后骨胶的性能进行了研究、讨论,并对改性后骨胶的结构和性能进行了表征。结果表明,制备交联型骨胶/MMT复合物的最佳工艺为反应温度30℃、反应时间1h、pH-7,所得骨胶的韧性得到了改善,热稳定性也有所提高。%The modified bone glue was prepared by grafting copolymerization with glutaraldehyde as modifier, and then it was intercalated by montmorillonite. The influencing factors and performance of glutaraldehyde bone glue intercalated by montmorillonite was studied and discussed. The performance was characterized. The result showed that the optimum process conditions are reaction temperature 30 ℃, reaction time 1 h, and pH value 7; the toughness and thermal stability of the bone glue is improved under these conditions.

  2. Influence of montmorillonites exchange capacity on the basal spacing of cation–anion organo-montmorillonites

    Energy Technology Data Exchange (ETDEWEB)

    Sanqin, Wu [School of Materials Sciences and Technology, China University of Geosciences, No. 29 Xueyuan Road, Beijing, 100083 (China); Zepeng, Zhang, E-mail: unite508@163.com [School of Materials Sciences and Technology, China University of Geosciences, No. 29 Xueyuan Road, Beijing, 100083 (China); Yunhua, Wang [Zhejiang Fenghong New Material Co., Ltd. (China); Libing, Liao [School of Materials Sciences and Technology, China University of Geosciences, No. 29 Xueyuan Road, Beijing, 100083 (China); Jiansheng, Zhang [Tangshan College, Tangshan 063000 (China)

    2014-11-15

    Graphical abstract: This picture shows the distribution of organic modifier (CTAB and SDS) in Mt interlayer and the basal spacing changes of Mt modified by CTAB and SDS. Organic modifier molecule in Mt interlayer is more and more orderly. The basal spacing of Mt is from 1.5 nm to 5 nm as modifier added. - Highlights: • The d{sub 001} of Ca-Mt, R-Na-Mt, Na-Mt modified by CTAB and SDS can reach 5 nm. • It is easier to get cation–anion OMt with greater d{sub 001} if CEC is lower. • The organic molecules distribution in cation–anion OMt was analyzed. • The influence mechanism of Ca-Mt CEC on the d{sub 001} was discussed. - Abstract: With cationic and anionic surfactants cetyltrimethylammonium bromide (CTAB) and sodium dodecylsulfonate (SDS) as modifiers, Ca-montmorillonites (Ca-Mt), artificial Na-montmorillonites (R-Na-Mt) and natural Na-montmorillonites (Na-Mt) with different cation exchange capacity (CEC) were modified by solution intercalation method, respectively. Then cation–anion organo-montmorillonites (OMt) were prepared. The influence of CEC on the basal spacing of cation–anion OMt and the influence mechanism were discussed by X-ray diffraction (XRD) and zeta potential testing. The results indicate that the basal spacing of cation–anion OMt is related to CEC. For the same type montmorillonites, the basal spacing of cation–anion OMt decreases with the increase of CEC and it is easier to get cation–anion OMt with greater basal spacing when CEC is lower. Moreover, the CEC of Na-Mt has the greatest influence on the basal spacing of cation–anion OMt.

  3. Engineering New Layered Solids from Exfoliated Inorganics: a Periodically Alternating Hydrotalcite - Montmorillonite Layered Hybrid

    Science.gov (United States)

    Chalasani, Rajesh; Gupta, Amit; Vasudevan, Sukumaran

    2013-12-01

    Two-dimensional (2D) nanosheets obtained by exfoliating inorganic layered crystals have emerged as a new class of materials with unique attributes. One of the critical challenges is to develop robust and versatile methods for creating new nanostructures from these 2D-nanosheets. Here we report the delamination of layered materials that belonging to two different classes - the cationic clay, montmorillonite, and the anionic clay, hydrotalcite - by intercalation of appropriate ionic surfactants followed by dispersion in a non-polar solvent. The solids are delaminated to single layers of atomic thickness with the ionic surfactants remaining tethered to the inorganic and consequently the nanosheets are electrically neutral. We then show that when dispersions of the two solids are mixed the exfoliated sheets self-assemble as a new layered solid with periodically alternating hydrotalcite and montmorillonite layers. The procedure outlined here is easily extended to other layered solids for creating new superstructures from 2D-nanosheets by self-assembly.

  4. Preparation and characterization of 3-aminopropyl-triethoxysilane grafted montmorillonite and acid-activated montmorillonite

    Institute of Scientific and Technical Information of China (English)

    SHEN Wei; HE HongPing; ZHU JianXi; YUAN Peng; MA YueHong; LIANG XiaoLiang

    2009-01-01

    3-aminopropyltriethoxysilane grafted montmorilionites were synthesized with montmorillonite, acid-activated montmorillonites and 3-aminopropyltriethoxysilane in ethanol-water mixture. The resulting products were investigated using Fourier transform infrared (FTIR) spectroscopy, X-ray diffraction (XRD), thermogravimetric analysis (TG). XRD patterns demonstrated that silane was intercalated into the montmorillonite gallery, indicated by increasing basal spacings. These intercalated silanes proba-bly adopt bilayer arrangement models within the montmorillonite and acid-activated montmorillonites interlayer spaces. TG and DTG curves indicate that acidification results in a decrease of the thermal stability of the resultant montmorillonites. Silane grafting leads to a surface property transformation of montmorillonite from hydrophilicity to lipophilicity and an increase of the thermal stability of the con-densed silanes.

  5. Study on Modification of Epoxy Resin by Intercalation Polymerization Method with Using Nano Montmorillonite as Raw Materials%纳米蒙脱土插层聚合改性环氧树脂

    Institute of Scientific and Technical Information of China (English)

    李成吾; 张天罡; 刘艳辉; 左继成; 于柱

    2011-01-01

    以纳米蒙脱土为原料,采用插层聚合法制备了改性增韧环氧树脂.通过正交实验考查了混合时间、混合温度、蒙脱土类型、蒙脱土含量对改性环氧树脂断裂伸长率的影响.实验结果表明混合时间对改性环氧树脂的断裂伸长率影响最大,当混合时间为2h,混合温度为70℃,采用DK1类型的蒙脱土,添加量为2%时,制备的改性环氧树脂断裂伸长率为12.11%,冲击强度为13.61MPa.%The modified toughened epoxy resin was preparcd with using nano montmorillonite as materials by intercalation polymerization method.The effects of reaction temperature, reaction time, montmorillonite type and content on the elongation at break of the modified epoxy resin were investigated by orthogonal experiment. The results showed that reaction time had a great effect on elongation at break of the modified epoxy resin.When the reaction temperature was 70℃, reaction time was 2h, montmorillonite type was DK1 and content was 2%, the elongation at breaking of the modified epoxy resin was up to 12.11% and the impact strength was 13.61MPa.

  6. Effect of alkyl length of cationic surfactants on desorption of Cs from contaminated clay

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Bo Hyun; Park, Chan Woo; Yang, Hee Man; Seo, Bum Kyoung; Lee, Kune Woo [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of); Park, So Jin [Chungnam National University, Daejeon (Korea, Republic of)

    2017-03-15

    In this study, desorption characteristics of Cs from clay according to the hydrophobic alkyl chain length of the cationic surfactant were investigated. Alkyltrimethylammonium bromide was used as a cationic surfactant, and the length of the hydrophobic alkyl chain of the cationic surfactant was varied from –octyl to –cetyl. The adsorbed amount of the cationic surfactant on montmorillonite increased with the length of the hydrophobic alkyl chain, and intercalation of the cationic surfactant into the clay interlayer increased the interlayer distances. The Cs removal efficiency was also enhanced with increasing alkyl chain length, and the cationic surfactant with the cetyl group showed a maximum Cs removal efficiency of 99±2.9%.

  7. 氧化锌插层蒙脱土纳米复合材料的制备及其光催化活性%Facile Synthesis of ZnO Intercalated Montmorillonite Nanocomposites and Their Photocatalytic Activity

    Institute of Scientific and Technical Information of China (English)

    刘俊莉; 赵燕茹; 马建中; 马歌

    2016-01-01

    Herein,we report a facile synthesis of ZnO/montmorillonite (MMT)nanocomposites.The layered structures of MMT was firstly expanded and partly exfoliated into ultrathin few layer structures by fully hydrating and freezing and then ZnO nanoparticles (NPs)were embedded into the layers by a controllable hydrolysis process.The results indicated that ZnO NPs (1-3 nm in diameter)were intercalated in the layers of MMT or (10-25 nm in dia-meter)anchored on the surface of MMT.The nanocomposites was found to have an excellent performance for the deg-radation of methyl orange (MO),which inferred a potential application as a novel photocatalyst.Analysis showed the interlayer charge of the intercalated nanostructure can significantly inhibit the electron-hole recombination in photoca-talysis process.The enhanced photocatalytic activity of ZnO/MMT nanocomposites could be ascribed to the synergis-tic effect of the MMT loaded with nano-ZnO.%采用一种简便的方法制备了氧化锌插层蒙脱土纳米复合材料。首先将蒙脱土充分充水后进行冷冻,具有层状结构的蒙脱土充水后会发生膨胀,部分从块状的蒙脱土上剥离形成超薄的片层结构。然后通过可控的水热过程使氧化锌纳米粒子进入蒙脱土层间或覆盖于表面。结果表明,直径1~3 nm 的纳米氧化锌会插层于蒙脱土的层间,而直径达10~25 nm的纳米氧化锌则会镶嵌在蒙脱土表面。该纳米复合材料对模拟污染物甲基橙具有优异的光催化性能。

  8. POLYMER/MONTMORILLONITE COMPLEXES:PREPARATION AND INTERACTIONS WITH ROSIN ACID

    Institute of Scientific and Technical Information of China (English)

    Lihong Zhao; Wenxia Liu

    2004-01-01

    Polymer/montmorillonite complexes were prepared via intercalating polymers of low molecular weight into layers of montmorillonite and evaluated for their interactions with rosin acid. Three polymers from various amines modified by epichlorohydrin and an acidified diethylenetriamine were separately intercalated into montmorillonite via direct solution intercalation. X-ray diffraction patterns are performed to obtain information about the intercalation of these agents. The examination revealed that it was feasible for the direct intercalation of polymers, while hard for the unmodified diethylenetriamine. Adsorption isotherm curves were established to assess the efficiency of the various montmorillonites including the intercalated montmorillonites, the simple mixtures of the corresponding intercalation agents and ordinary montmorillonite in removing pitch from water solution. From the adsorption behavior of various samples, it was found that the interaction of the montmorillonite with pitch was not only through van der Waals attraction, but also through electrostatic interactions. Both the organo-philic and the surface electrostatic properties of the montmorillonites are important for successful pitch control.

  9. Adsorption of Environmental Pollutants on Pillared Montmorillonite

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    Both inorganic and organic pillared montmorillonites were used to adsorb phenol.Batch kinetics and isotherm studies were carried out to evaluate the effect of equilibrium time and pH on adsorption of phenol by montmorillouites and re-adsorbing characteristics of pillared montmorillonites.The adsorption of phenol increased with increasing solution pH values.The elimination ratio of phenol from the solution by the absorption of organic modified pillared montmorillonite (OrPMt) reached equilibrium quickly after vibrating for 5 minutes.Meanwhile for organic montmorillonite (OrMt),pillared montmorillouite (PMt) and montmorillonite (Mt),the time to reach phenol-absorption equilibrium were 20,30 and 90 minutes,respectively.The adsorbing capacity of the pillared montmorillonite modified with surfactant improved greatly.The phenol-adsorbing capacity of pillared montmorillonites mainly depended on microporous structure and surface component of the modified clays.After calcination at 500 ℃,the pillar structure and the basal spacing (1.83 nm) were still stable.So the pillared montmorillonite could be recycled,and it was a potential material for adsorbing environmental pollutants.

  10. EFFECT OF ORGANOPHILIZATION AND INTERLAMELLAR SILYLATION OF MONTMORILLONITE ON COMPATIBLIZATION OF POLYMER COMPOSITES

    Directory of Open Access Journals (Sweden)

    Mamdouh Abdel Rahim

    2016-12-01

    Full Text Available Sodium montmorillonite (Na-Mt was modified by cetyltriemethylammoniumbromide (CTAB through cation exchange technique followed by grafting with 3-aminopropyltriethoxysilane (APT. The effects of organophillic surface treatments of montmorillonite on compatibilization of natural rubber (NR /acrylonitrile butadiene rubber (NBR blends was investigated. Physico-mechanical properties of rubber nanocomposites compatibilized with organomodified montmorillonite revealed strong nanocomposite with high tensile properties, impact strength and good resistance to flex fatigue, abrasion and compression set. Dynamic mechanical thermal analysis (DMTA revealed a marked increase in storage modulus (E' and lesser damping characteristics of organically modified clay mineral polymer nanocomposites (CPN due to intercalation of organophilic montmorillonite by rubber matrix. The morphology of the blends became homogeneous and smoother with the presence of exofoliated/intercalated organically modified montmorillonite. Organomodified layered silicate sheets of montmorillonite greatly enhanced barrier properties by creating tortuous path that retarded the progress of solvent molecules through rubber matrix.

  11. Synthesis and characterization of nanohybrid of montmorillonite and zinc oxide

    Energy Technology Data Exchange (ETDEWEB)

    Chagas, Beatriz S.; Mendes, Luis C.; Brito, Alice S., E-mail: biachagas@ima.ufrj.b [Universidade Federal do Rio de Janeiro (IMA/UFRJ), RJ (Brazil). Inst. de Macromoleculas Profa. Eloisa Mano

    2009-07-01

    Zinc oxide-aluminosilicate nanohybrids through a hydrothermal reaction of a colloidal suspension of exfoliated montmorillonite nanosheets and zinc oxide in acid solution, performed in three different routes, were synthesized. The products were characterized by wide angle X-ray diffraction (WAXD). In all routes, it was found that the intercalation of zinc oxide into the host montmorillonite gallery was successfully performed so that the crystalline peaks of the montmorillonite and zinc oxide were suppressed from the X-ray patterns. The use of ultrasound decreased the reaction time.(author)

  12. 羧基功能化和表面活性剂修饰对石墨烯电化学性能的影响%Superior Electrochemical Performance of Graphene via Carboxyl Functionalization and Surfactant Intercalation

    Institute of Scientific and Technical Information of China (English)

    于建华; 许丽丽; 朱倩倩; 王晓霞; 云茂金; 董立峰

    2016-01-01

    通过简单的两步溶液法对石墨烯进行羧基接枝和表面活性剂修饰,并研究其电化学性能。研究结果表明,与纯石墨烯(比电容50 F/g)相比,表面活性剂本身并不能有效提高石墨烯的比电容(45 F/g),羧基功能化可以将石墨烯的比电容提高至130 F/g。而羧基功能化和表面活性剂修饰双处理工艺能够将石墨烯的比电容提高到230 F/g,且经800次充放电循环后其比电容仍然具有95%的保持率,表明该材料具有良好的循环稳定性。因此,调控石墨烯的表面化学特性对提高其电化学性能具有重要的意义。%Superior capacitance of carboxyl functionalized and surfactant-intercalated graphene were prepared by a relatively simple with two-step solution-based processing technique. In comparison to pristine graphene, surface car-boxyl functionalization and surfactant intercalation can tailor its specific capacitance from 50 F/g to 230 F/g. Mean-while, the modified materials retain more than 95% of their capacitance after 800 charge-discharge cycles, demon-strating good cyclic stability. Surfactant itself cannot improve the performance of pristine graphene as graphene inter-calated with surfactant has a specific capacitance of 45 F/g, however, carboxyl groups can dramatically enhance spe-cific capacitance to 130 F/g. The excellent performance of functionalized graphene emphasizes the importance of con-trolling its surface chemistry.

  13. Silylation of montmorillonite surfaces: dependence on solvent nature.

    Science.gov (United States)

    Su, Linna; Tao, Qi; He, Hongping; Zhu, Jianxi; Yuan, Peng; Zhu, Runliang

    2013-02-01

    Silylation of clay mineral surfaces has attracted much attention due to their extensive applications in materials science and environmental engineering. Silylation of montmorillonite surfaces with 3-aminopropyltriethoxysilane was carried out in polar-protic and nonpolar solvents. The swelling property of the silylated montmorillonites was investigated by intercalating with cetyltrimethylammonium bromide. Silylated montmorillonites prepared in nonpolar solvents showed a larger amount of loaded silane and a higher extent of condensation among different silane molecules, comparing with those prepared in polar-protic solvents with high dielectric constant. Meanwhile, the silylated montmorillonites prepared in nonpolar solvents displayed poor swelling property due to the linkage between silane oligomers and clay layers, that is, the neighboring clay layers were locked by the silane oligomers. The present study demonstrated that the polarity of the solvents used had an important influence on the extent of grafting, interlayer structure, and swelling property of the silylated products. This is of high importance for synthesis and application of silylated clay minerals.

  14. AFM study of montmorillonite

    Energy Technology Data Exchange (ETDEWEB)

    Pettersson, Torbjoern; Thormann, Esben; Claesson, Per (Dept. of Chemistry, Surface Chemistry, Royal Inst. of Technology, Stockholm (Sweden))

    2010-02-15

    Na-montmorillonite and Ca-montmorillonite particles have been attached to molecularly flat mica surfaces using simple evaporation of montmorillonite solutions. The particles stick to the surface by strong van der Waals forces. The homogeneity of the montmorillonite particle surfaces has been evaluated by AFM imaging and by AFM force raster measurements. As a control, molecularly smooth mica surfaces were used, and the data obtained for montmorillonite was compared with the data obtained for mica. In images of the size 100x100 nm we can identify variations on the Na-montmorillonite particle surfaces. This variation is attributed to inhomogeneities of the montmorillonite particles. The inhomogeneous nature of the montmorillonite surface is also clearly demonstrated by the force raster measurement, in particular the force raster adhesion maps show larger variations and a more patterned structure for montmorillonite than for mica. Thus, any attempt to model the interaction between montmorillonite particles using a model of ideally flat surfaces with a homogeneous charge distribution is an oversimplification. We suggest that this explains the differences between measured swelling pressures and modelling results

  15. Effect of compound organification of montmorillonite on the structure and properties of polypropylene/montmorillonite nanocomposites

    Institute of Scientific and Technical Information of China (English)

    HONG Haoqun; JIA Demin; HE Hui

    2007-01-01

    In this paper,reactive organic montmorillonite (RMMT),prepared with compound alkylammoniums,were used in ternary-monomer solid phase graft copolymerization in order to enhance the melting intercalation of montmoril-lonite (MMT),stabilize the intercalated structure,and prepare the exfoliated polypropylene/montrnorillonite (PP/MMT) nanocomposites (PPMN).The structure and properties of PPMN were studied by X-ray diffraction (XRD),Fourier transform infrared spectroscopy (FTIR),transmission elec-tron microscope (TEM),etc.Results show that the compound organification,solid phase graft copolymerization really favored the melting intercalation.The compound organifica- tion and exothermic process of the solid phase copolymeriza-tion promoted the melting intercalation.The mechanical properties,melt flow rate and Vicat softening point of PPMN significantly had a preferable reinforced state at 6-8 phr PP/MMT graft copolymers (PPGM).The increase of the mechanical properties and thermal properties was owed to the reinforcement of the exfoliated MMT and the compatibiliza-tion of the oligomers built by the polar monomers during the solid phase graft copolymerization.The improvement of the fluidity of PPMN derived from the plasticization of the exfoliated MMT and oligomers.

  16. Structure and Dynamics of Nonionic Surfactant Aggregates in Layered Materials.

    Science.gov (United States)

    Guégan, Régis; Veron, Emmanuel; Le Forestier, Lydie; Ogawa, Makoto; Cadars, Sylvian

    2017-09-26

    The aggregation of surfactants on solid surfaces as they are adsorbed from solution is the basis of numerous technological applications such as colloidal stabilization, ore flotation, and floor cleaning. The understanding of both the structure and the dynamics of surfactant aggregates applies to the development of alternative ways of preparing hybrid layered materials. For this purpose, we study the adsorption of the triethylene glycol mono n-decyl ether (C10E3) nonionic surfactant onto a synthetic montmorillonite (Mt), an aluminosilicate clay mineral for organoclay preparation with important applications in materials sciences, catalysis, wastewater treatment, or as drug delivery. The aggregation mechanisms follow those observed in an analogous natural Mt, with the condensation of C10E3 in a bilayer arrangement once the surfactant self-assembles in a lamellar phase beyond the critical micelle concentration, underlining the importance of the surfactant state in solution. Solid-state (1)H nuclear magnetic resonance (NMR) at fast magic-angle spinning (MAS) and high magnetic field combined with(1)H-(13)C correlation experiments and different types of (13)C NMR experiments selectively probes mobile or rigid moieties of C10E3 in three different aggregate organizations: (i) a lateral monolayer, (ii) a lateral bilayer, and (iii) a normal bilayer. High-resolution (1)H{(27)Al} CP-(1)H-(1)H spin diffusion experiments shed light on the proximities and dynamics of the different fragments and fractions of the intercalated surfactant molecules with respect to the Mt surface. (23)Na and (1)H NMR measurements combined with complementary NMR data, at both molecular and nanometer scales, precisely pointed out the location of the C10E3 ethylene oxide hydrophilic group in close contact with the Mt surface interacting through ion-dipole or van der Waals interactions.

  17. Influence of the surfactant in the shear-induced crystallization kinetics of HDPE/MMT nano composites; Influencia do tratamento superficial da montmorilonita na cinetica de cristalizacao induzida por fluxo de nanocompositos de HDPE

    Energy Technology Data Exchange (ETDEWEB)

    Bonel, A.B. [Universidade Federal de Sao Carlos (DEMA/UFSCAR), SP (Brazil). Dept. de Engenharia de Materiais; Beatrice, C.A.G.; Marini, J.; Bretas, R.E.S., E-mail: bretas@ufscar.b [Universidade Federal de Sao Carlos (UFSCAR), SP (Brazil). Programa de Pos-Graduacao em Ciencia e Engenharia de Materiais

    2010-07-01

    High-density polyethylene (HDPE) compatibilized with ethylene vinyl-acetate copolymer (EVA)r, with 5 wt% of two different organically modified montmorillonite (with polar and non-polar surfactant) were prepared by melt blending in a corrotational twin-screw extruder at 225 deg C, 100rpm and 3kg/h. Both nanocomposites were characterized by wide-angle x-ray scattering (WAXS), transmission electron microscopy (TEM) and rheological measurements. The nanoclay's lamellas were intercalated in both samples. The storage and the loss moduli of the nanocomposites, at low frequencies, showed that the particles of the nanoclay modified with a polar surfactant were well dispersed thru the HDPE matrix, while the particles of the other nanoclay were well distributed thru the matrix. The presence of a nanoclay modified with a non-polar surfactant reduced the induction times for the crystals growth, due to the strong interactions with the HDPE chains. (author)

  18. Properties of Wood/Montmorillonite Nanocomposites

    Institute of Scientific and Technical Information of China (English)

    LV Wenhua; ZHAO Guangjie

    2006-01-01

    With montmorillonite (MMT) organically modified as organophilic-MMT (OMMT) and water-soluble phenol formaldehyde resin (PF) as intermediate, the nanocomposites of Chinese fir (Cunninghamia lanceolata) wood and MMT, i.e. WMNC, were prepared via nano intercalation compounding, some properties of WMNC were analyzed. Results show that, compared with Chinese fir wood and its PF-impreg, WMNC has lower humidity and water absorption, better dimension stability, higher longitudinal compressive strength, abrasive resistance, fire-resistance, and water-leaching resistance with a very low mass ratio about 3% of MMT. The nano intercalation compounding of wood and exfoliated MMT nanolamellae is very promising. More studies should be carried out to fully reveal the nanosize effects and the special properties of WMNC.

  19. Preparation and characterization of mixed hydroxy-Fe-Al pillared montmorillonite with large basal spacing

    Institute of Scientific and Technical Information of China (English)

    ZENG Xiu-qiong; LIU Wei-ping

    2004-01-01

    Mixed hydroxy-Al-Fe pillared montmorillonites with large basal spacing were successfully prepared through cation-exchanging of Na+ - montmorillonite with mixed hydroxy-Al and hydroxy-Fe pillaring solutions made from hydrolysis of corresponding metal salts, followed by calcination to convert hydroxy-Al and hydroxy-Fe into intercalated polycations. According to XRD analysis, the basal spacing d(001 ) of pillared products dramatically enlarged from 12.7 A in the Na-montmorillonite to 81 A in the hydroxy-Fe -montmorillonite and 77.5 A in mixed hydroxy-Al-Fe-montmorillonite. The N2 BET surface areas of the pillared montmorillonites also greatly increased to more than 200m2/g as compared to about 27 m2/g for the Na-montmorillonite. IR analysis of hydroxy-Fe, and mixed hydroxy-Al-Fe pillared montmorillonites revealed a new absorption vibration at 1384 cm-1 wavelength. XRF elemental analysis data also showed a high content of Fe2 O3 in the hydroxy-Fe pillared montmorillonite.

  20. Nanocomposites of polyamide 6/residual monomer with organic-modified montmorillonite and their nanofibers produced by electrospinning

    Directory of Open Access Journals (Sweden)

    Cesar Augusto Gonçalves Beatrice

    2012-08-01

    Full Text Available Nanocomposites of an organic-modified montmorillonite (MMT and polyamide 6 (PA6 with a residual monomer were produced by melt mixing in a torque rheometer. By wide angle X-rays diffraction (WAXD, intercalated/exfoliated structures were observed in the PA6/MMT nanocomposites with 3 and 5 wt. (% of MMT; on the other hand, when 7 wt. (% of MMT was added, a nanocomposite with exfoliated structures was obtained due to the predominant linking reactions between the residual monomer and the "nanoclays" organic surfactant. Solutions of these PA6/MMT nanocomposites at 15, 17 and 20 wt. (% in formic acid were prepared. The 3 and 5 wt. (% nanocomposites were successfully electrospun; however, electrospinning of the 7 wt. (% nanocomposite was not possible. WAXD, scanning and transmission electron microscopy results showed that the 3 and 5 wt. (% nanofibers with average diameter between 80-250 nm had exfoliated structures. These results indicate that the high elongational forces developed during the electrospinning process changed the initial intercalated/exfoliated structure of the nanocomposites to an exfoliated one.

  1. Effect of different montmorillonites on rheological properties of bitumen/clay nanocomposites

    Institute of Scientific and Technical Information of China (English)

    陶园园; 余剑英; 李斌; 冯鹏程

    2008-01-01

    Different composites of organomodified montmorillonite(OMMT)/bitumen were prepared by melt blending with hexadecyl dimethyl benzyl ammonium modified montmorillonite(HBM) and double octadecyl dimethyl ammonium modified montmorillonite(DOM).The structures of two kinds of montmorillonite modified bitumen were characterized by X-ray diffraction(XRD).The effects of different montmorillonites on the dynamic rheological properties of the modified bitumens were investigated by dynamic shear rheometer(DSR).The XRD results show that DOM modified bitumen forms an intercalated structure,whereas the HBM modified bitumen forms an exfoliated structure.DSR results indicate that OMMT modified bitumens exhibit higher complex modulus,lower phase angle than pristine bitumen,which means that the resistance to rutting at high temperatures of pristine bitumen is improved due to the introduction of OMMT.Compared with DOM modified bitumen,HBM modified bitumen shows better rutting resistance,which is contributed to the formation of exfoliated structure in HBM modified bitumen.

  2. The Effect of a Rapid Heating Rate, Mechanical Vibration and Surfactant Chemistry on the Structure–Property Relationships of Epoxy/Clay Nanocomposites

    Science.gov (United States)

    Nuhiji, Betime; Attard, Darren; Thorogood, Gordon; Hanley, Tracey; Magniez, Kevin; Bungur, Jenny; Fox, Bronwyn

    2013-01-01

    The role of processing conditions and intercalant chemistry in montmorillonite clays on the dispersion, morphology and mechanical properties of two epoxy/clay nanocomposite systems was investigated in this paper. This work highlights the importance of employing complementary techniques (X-ray diffraction, small angle X-ray scattering, optical microscopy and transmission electron microscopy) to correlate nanomorphology to macroscale properties. Materials were prepared using an out of autoclave manufacturing process equipped to generate rapid heating rates and mechanical vibration. The results suggested that the quaternary ammonium surfactant on C30B clay reacted with the epoxy during cure, while the primary ammonium surfactant (I.30E) catalysed the polymerisation reaction. These effects led to important differences in nanocomposite clay morphologies. The use of mechanical vibration at 4 Hz prior to matrix gelation was found to facilitate clay dispersion and to reduce the area fraction of I.30E clay agglomerates in addition to increasing flexural strength by over 40%. PMID:28811457

  3. The Effect of a Rapid Heating Rate, Mechanical Vibration and Surfactant Chemistry on the Structure–Property Relationships of Epoxy/Clay Nanocomposites

    Directory of Open Access Journals (Sweden)

    Kevin Magniez

    2013-08-01

    Full Text Available The role of processing conditions and intercalant chemistry in montmorillonite clays on the dispersion, morphology and mechanical properties of two epoxy/clay nanocomposite systems was investigated in this paper. This work highlights the importance of employing complementary techniques (X-ray diffraction, small angle X-ray scattering, optical microscopy and transmission electron microscopy to correlate nanomorphology to macroscale properties. Materials were prepared using an out of autoclave manufacturing process equipped to generate rapid heating rates and mechanical vibration. The results suggested that the quaternary ammonium surfactant on C30B clay reacted with the epoxy during cure, while the primary ammonium surfactant (I.30E catalysed the polymerisation reaction. These effects led to important differences in nanocomposite clay morphologies. The use of mechanical vibration at 4 Hz prior to matrix gelation was found to facilitate clay dispersion and to reduce the area fraction of I.30E clay agglomerates in addition to increasing flexural strength by over 40%.

  4. Hydrotalcite-TiO2 magnetic iron oxide intercalated with the anionic surfactant dodecylsulfate in the photocatalytic degradation of methylene blue dye.

    Science.gov (United States)

    Miranda, Liany D L; Bellato, Carlos R; Milagres, Jaderson L; Moura, Luciano G; Mounteer, Ann H; de Almeida, Marciano F

    2015-06-01

    The new magnetic photocatalysts HT/TiO2/Fe and HT-DS/TiO2/Fe, modified with the anionic surfactant sodium dodecylsulfate (DS) were successfully synthesized in this work. Titanium dioxide (anatase) followed by iron oxide were deposited on the hydrotalcite support. Several catalyst samples were prepared with different amounts of titanium and iron. The photocatalysts were characterized by infrared and Raman spectroscopy, X-ray diffraction, scanning electron microscopy. Photocatalytic performance was analyzed by UV-visible radiation (filter cutoff, λ > 300 nm) of an aqueous solution (24 mg/L) of methylene blue (MB). The most efficient catalyst was obtained at an iron oxide:TiO2 molar ratio of 2:3. This catalyst showed high photocatalytic activity, removing 96% of the color and 61% of total organic carbon from the MB solution after 120 min. It was easily removed from solution after use because of its magnetic properties. The reuse of the HT-DS/TiO2/Fe23 catalyst was viable and the catalyst was structurally stable for at least four consecutive photocatalytic cycles.

  5. Flow-induced crystallization of a nano composite of poly(butylene adipate-co-terephthalate)/montmorillonite; Cinetica de cristalizacao induzida por fluxo de nanocomposito de poli(butileno adipato-co-tereftalato)/montmorilonita

    Energy Technology Data Exchange (ETDEWEB)

    Bonel, Alan B. [Universidade Federal de Sao Carlos. UFSCar, Departamento de Engenharia de Materiais DEMa, SP (Brazil); Rego, Bruna T.; Beatrice, Cesar A.G.; Marini, Juliano; Bretas, Rosario E.S., E-mail: bretas@ufscar.br [Universidade Federal de Sao Carlos. UFSCar, Programa de Pos-Graduacao em Ciencia e Engenharia de Materiais, SP (Brazil)

    2011-07-01

    Poly(butylene adipate-co-terephthalate) (PBAT) with 5wt% of an organically modified montmorillonite with polar surfactant was prepared by melt blending in a co-rotational twin-screw extruder at 160 degree C. 100rpm and 1 kg/h. Both pure polymer and nano composite were characterized by wide measurements. The study of the flow-induced crystallization was also done by rheological measurements, monitoring the viscosity as a function of time. The nano clay's lamellas were intercalated in the polymer m loss moduli of the nano composite, at low frequencies, showed that the particles of the nano clay were well dispersed and distributed thru the PBAT matrix. Finally, the presence of the nano clay's particles reduced the induction tim crystals growth, due to the strong interactions with the PBAT chains. (author)

  6. Research on the Preparation and Mechanism of the Organic Montmorillonite and Its Application in Drilling Fluid

    Directory of Open Access Journals (Sweden)

    Xiaolong Wang

    2015-01-01

    Full Text Available The study focused on the relation of structure, property, and application of composite prepared by organic cation intercalated montmorillonite (Mt. Herein a new kind of green and steady ionic liquid, 1-hexadecyl-3-methylimidazolium chloride monohydrate (C12mimCl, was chosen as the intercalated agent. This study used molecular dynamics (MD modeling to examine the interlayer microstructures of montmorillonite intercalated with C12mimCl. The C12mimCl intercalation was relatively fast with a large rate constant. The process was affected by the initial concentration of the solution; the basal spacing increased to 2.08 nm after intercalation. The coordination of electrostatic interaction and hydrogen bonding expelled water molecules out of the clay gallery and bound the layer together, which led to the dehydration of clay. The intercalation of C12minCl into Mt interlayer space affected rheology of the system and improved various properties. This organic clay composite was environmentally friendly and could be used in drilling fluid system. These models provided insights into the prediction of synthesized organic cationic-clay microstructure and guidelines for relevant engineering applications.

  7. Modification of nano-sized layered double hydroxides by long-chain organic aliphatic surfactants

    OpenAIRE

    RAMASAMY ANBARASAN; SEUNG SOON IM; WANDUC LEE

    2008-01-01

    The inter-layer anion of layered double hydroxides (LDH) with a hydrotalcite (HT)-like structure was ion-exchanged with various organic surfactants, particularly with long chain aliphatic surfactants. After the ion-exchange process, the basal spacing of the LDH was increased and the increase of the basal spacing depended on various factors, such as the intercalation capacity functionality and orientation capability of the surfactant. Of the employed surfactants, stearic acid intercalated LDH ...

  8. Effect of Different Organic Modifiers on the Tensile Properties of PVC/EVA/Montmorillonite Composites

    Institute of Scientific and Technical Information of China (English)

    Chao Ying WAN; Yong ZHANG; Yin Xi ZHANG

    2004-01-01

    Poly (vinyl chloride)/ethylene-vinyl acetate/montmorillonite (PVC/EVA/OMMT) composites were prepared by melt blending method. Two kinds of montmorillonites were organically modified by trimethyloctadecyl ammonium and dimethyl bis (hydrogenated tallow) ammonium, respectively. The morphology and tensile properties of the resultant composites were discussed in terms of the modifier type and OMMT content. The PVC/EVA/OMMT composites have intercalated structure, which is independent of the polarity of the modifiers, while the tensile properties show strong dependence on the modifier type. The OMMT modified by polar modifier gives higher tensile ductile and strength of PVC/EVA/OMMT composites.

  9. Structures and Mechanical Properties of PVC/Na+- Montmorillonite Nanocomposites

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    Poly (vinyl chloride)/Na+-montmorillonite (PVC/MMT) nanocomposites with different MMT contents were prepared via melt blending. Wide-angle X-ray diffraction (WAXD) and transmission electron microscopy (TEM) were used to characterize the structures. Effects of MMT content on the mechanical properties were also studied. It is found that PVC molecular chains can intercalate into the gallery of MMT layers during melt blending process, the stiffness and toughness of the composites are improved simultaneously within 0.5~7wt% MMT content, and the transparency and mechanical properties decrease as MMT content further increases.

  10. Effects of Hydrophilic Monomer Types and Level on Polystyrene-Acrylate/montmorillonite Nanocomposite Made by Emulsion Polymerization

    Institute of Scientific and Technical Information of China (English)

    F.A.Zhang; L.Chen; J.Q.Ma; X.Yang

    2007-01-01

    1 Results Nanocomposite has attracted more and more interest all over the world.Polystyrene (PS) is a commercialized and mass-productive polymer,continuous research efforts have been devoted to the development of polystyrene/montmorillonite (PS/MMT) nanocomposites[1-2].But the polarity of styrene (St) is too small to intercalate the space between the clay layers.The polarity of hydrophilic monomer is so strong that it can intercalate the MMT easily,the intercalated smectic clays maybe exfoliated by usin...

  11. THE SYNTHESIS OF Cr2O3-PILLARED MONTMORILLONITE (CrPM AND ITS USAGE FOR HOST MATERIAL OF p-NITROANILINE

    Directory of Open Access Journals (Sweden)

    Karna Wijaya

    2010-06-01

    Full Text Available The synthesis of Cr2O3-pillared montmorillonite (CrPM and its usage for host material of p-nitroaniline have been conducted. The Cr2O3-pillared montmorillonite clays was prepared by a direct ion exchange method. First, the polyhydroxychromium as a pillaring spesies was intercalated into the interlayer region of the montmorillonite clays (purified clay in the monocation form, result in a montmorillonite-polyoxychromium intercalation compound. The precursors/pillaring spesies was not stable, hence it must be stabilized by calcination in order to transform the polyoxychromium via dehydration and dehydroxylation processes into Cr2O3. This oxide constituts the so-called pillar that prop the clay layers apart to a relatively large distance. The Cr2O3-pillared clays as a host material was added into ethanol solution saturated with p-nitroaniline, and mixture was stirred for 24 h at room temperature. The Na-montmorillonite, Cr2O3-pillared clay and p-nitroaniline-Cr2O3-pillared clay (pNA-CrPM were characterized by X-Ray Diffraction (XRD, Gas Sorption Analysis, Infrared Spectroscopy (FTIR and Activated Neutron Analysis (ANA methods. The result of research showed that basal spacing (d001 of Cr2O3-pillared montmorillonite (CrPM was 18,55 Å, meanwhile the basal spacing of the hydrated Na-montmorillonite was 14,43 Å. The specific surface area of the Cr2O3-pillared montmorillonite was 174,308 m2/g, whereas p-nitroaniline-Cr2O3-pillared clay (pNA-CrPM was 133,331641 m2/g. This fact indicated that p-nitroaniline has been included into the pore of the Cr2O3-pillared clay.   Keyword: montmorillonite, pillared-clay, ion exchange, intercalate.

  12. Synthesis of poly(furfuryl alcohol)/montmorillonite nanocomposites by direct in-situ polymerization

    Indian Academy of Sciences (India)

    Djamal Eddine Kherroub; Mohammed Belbachir; Saad Lamouri

    2015-02-01

    The purpose of this study was to obtain poly(furfuryl alcohol) nanocomposites with Algerian organically modified clay (termed 12-montmorillonite). The formation of poly(furfuryl alcohol) was confirmed by infrared spectroscopy (IR); the prepared nanocomposites were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM) and thermogravimetric analysis (TGA). The evolution of mechanical properties was also studied. The obtained results confirm the intercalation of molecules of salt in the clay layers, and a good interaction with the polymer, showing the formation of intercalated and/or exfoliated structures. The nanocomposites showed higher thermal stability compared to pure polymer, and the mechanical properties presented interesting and promising results.

  13. Synthesis of Polyamide-6/Montmorillonite Nanocomposites by Direct In-situ Polymerization Catalysed by Exchanged Clay

    Directory of Open Access Journals (Sweden)

    Djamal Eddine Kherroub

    2014-01-01

    Full Text Available The purpose of this study was to obtain polyamide-6 nanocomposites with national organically modified clay (termed 12-montmorillonite. The formation of polyamide-6 was confirmed by infrared spectroscopy (IR, the prepared nanocomposites were characterized by X-ray diffraction (XRD, transmission electron microscopy (TEM and thermogravimetric analysis (TGA. The evolution of mechanical properties was also studied. The obtained results confirm the intercalation of molecules of salt in the clay layers, and a good interaction with the polymer, showing the formation of intercalated and/or partially exfoliated structures. The nanocomposites showed higher thermal stability compared to pure polymer, and the mechanical properties presented interesting and promising results.

  14. Storylines in intercalation chemistry.

    Science.gov (United States)

    Lerf, A

    2014-07-21

    Intercalation chemistry will soon be a hundred years old. The period of greatest activity in this field of solid state chemistry and physics was from about 1970 to 1990. The intercalation reactions are defined as topotactic solid state reactions and the products--the intercalation compounds--are clearly distinguished from inclusion and interstitial compounds. After a short historical introduction emphasizing the pioneering work of Ulrich Hofmann, the central topics and concepts will be reviewed and commented on. The most important ones, in my view, are: dichalcogenide intercalation compounds, the electrochemical intercalation and the search for new battery electrodes, the physics of graphite intercalation compounds, and the staging and interstratification phenomena. The relation to other fields of actual research and the demands for forthcoming research will also be addressed.

  15. Polystyrene/Montmorillonite Nanocomposites: Study of the Morphology and Effects of Sonication Time on Thermal Stability

    Directory of Open Access Journals (Sweden)

    Mashael Alshabanat

    2013-01-01

    Full Text Available Polymer nanocomposites of polystyrene matrix containing 10% wt of organo-montmorillonite (organo-MMT were prepared using the solution method with sonication times of 0.5, 1, 1.5, and 2 hours. Cetyltrimethylammonium bromide (CTAB is used to modify the montmorillonite clay after saturating its surface with Na+ ions. Fourier transform infrared spectroscopy (FTIR, X-ray diffraction (XRD, scanning electron microscopy (SEM, and transmission electron microscopy (TEM were used to characterize the montmorillonite before and after modification by CTAB. The prepared nanocomposites were characterized using the same analysis methods. These results confirm the intercalation of PS in the interlamellar spaces of organo-MMT with a very small quantity of exfoliation of the silicate layers within the PS matrix of all samples at all studied times of sonication. The thermal stability of the nanocomposites was measured using thermogravimetric analysis (TGA. The results show clear improvement, and the effects of sonication time are noted.

  16. SYNTHESIS AND CHARACTERIZATION OF ORGANOMONTMORILLONITE AND POLYAMIDE 66/MONTMORILLONITE NANOCOMPOSITES

    Institute of Scientific and Technical Information of China (English)

    Cheng-shen Zhu; Xin Kang; Su-qin He; Liu-yang Wang; Li-yun Lu

    2002-01-01

    The montmorillonites (MMTs), layered, smectite-type silicates, were premodified by two different methods priorto the polymer melt intercalation. In one case MMTs were modified with cetyltrimethylammonium bromide (CTAB), andtermed as organomontmorillonites (OMMTs); in the other case MMTs were modified by nylon, and the products were calledmodified montmorillonites (MMMTs). The effects of CTAB and nylon on the MMTs were investigated by using TG andWAXD. The results show that interlayer spacings of CTAB and nylon modified MMTs are larger than that of sodium MMTs.Then, polyamide 66 (PA 66)/MMT nanocomposites were obtained through the method of melt intercalation of polymers. Thenanocomposites were characterized by WAXD, TEM and Molau experiments. The results indicate that the MMTs dispersehomogeneously in the PA 66 matrix. The mechanical properties of nanocomposites, such as tensile properties and flexuralproperties, were also measured and show a tendency to increase with increase of MMT content and reach the maximumvalues at 5phr MMT content. The heat distortion temperature (HDT) of the nanocomposites (7 phr) is about 32 K higher thanthat of pure PA 66.

  17. Controlled swelling and adsorption properties of polyacrylate/montmorillonite composites

    Energy Technology Data Exchange (ETDEWEB)

    Natkanski, Piotr [Faculty of Chemistry, Jagiellonian University, Ingardena 3, 30-060 Krakow (Poland); Kustrowski, Piotr, E-mail: kustrows@chemia.uj.edu.pl [Faculty of Chemistry, Jagiellonian University, Ingardena 3, 30-060 Krakow (Poland); Bialas, Anna; Piwowarska, Zofia [Faculty of Chemistry, Jagiellonian University, Ingardena 3, 30-060 Krakow (Poland); Michalik, Marek [Institute of Geological Sciences, Jagiellonian University, Oleandry 2a, 30-063 Krakow (Poland)

    2012-10-15

    A series of novel polyacrylate/montmorillonite composites was synthesized by in situ polymerization in aqueous slurry of clay. Dissociated (obtained by adding ammonium or sodium hydroxide) and undissociated forms of acrylic acid were used as monomers in the hydrogel synthesis. The structure and composition of the samples were studied by powder X-ray diffraction, diffuse reflectance infra-red Fourier transform spectroscopy, thermogravimetry and elemental analysis. It has been found that the kind of monomer influences strongly the location of a polymer chain in the formed composite. Complete intercalation of hydrogel into the interlayer space of montmorillonite was observed for sodium polyacrylate, whereas polyacrylic acid and ammonium polyacrylate mainly occupied the outer surface of the clay. The position of hydrogel determined the swelling and adsorption properties of the studied composites. The important factor influencing the kinetics of Fe(III) cation adsorption was pH. The analysis of adsorption isotherms allowed to propose the mechanism of Fe(III) cation adsorption. Highlights: Black-Right-Pointing-Pointer Polyacrylate hydrogels can be introduced into the interlayers of clay. Black-Right-Pointing-Pointer The position of hydrogel in the composite depends on the polymer type. Black-Right-Pointing-Pointer Ammonium polyacrylate places outside the clay, sodium one is intercalated into it. Black-Right-Pointing-Pointer Swelling and adsorption capacities can be controlled by the polymer position. Black-Right-Pointing-Pointer High adsorption efficiency in Fe(III) removal was observed.

  18. PREPARATION AND CHARACTERIZATION OF SOY PROTEIN ISOLATE(SPI)/MONTMORILLONITE(MMT) BIONANOCOMPOSITES

    Institute of Scientific and Technical Information of China (English)

    傅强

    2009-01-01

    The bionanocomposites of soy protein isolate(SPI)/montmorillonite(MMT) have been prepared successfully via simple melt mixing,in which MMT was used as nanofiller and glycerol was used as plasticizer.Their structures and properties were characterized with X-ray diffraction(XRD),differential scanning calorimetry(DSC),scanning electron microscopy(SEM),thermogravimetric analysis and tensile testing.XRD、TEM and SEM results indicated that the MMT layers could be easily intercalated by the SPI matrix even by si...

  19. Influence of Laurolactam Content on the Clay Intercalation of Polyamide 6,12/Clay Nanocomposites Synthesized by Open Ring Anionic Polymerization

    OpenAIRE

    E. N. Cabrera Álvarez; L. F. Ramos de Valle; Rodríguez González, F. J.; Soriano-Corral, F.; Díaz De León, R. E.

    2012-01-01

    In situ anionic homo- and copolymerization of caprolactam (CL) and laurolactam (LL) with sodium montmorillonite clay (NaMMT) was carried out using two different initiators, sodium caprolactamate (CLNa) and caprolactam magnesium bromide (CLMgBr). Degree of conversion and final molecular weight were used to assess the advancement and efficiency of the polymerization reaction and X-ray diffraction and electron microscopy were used to evaluate the sodium montmorillonite clay intercalation/exfolia...

  20. Removal of aromatic amines from water by montmorillonite-(cerium or zirconium) phosphate crosslinked compounds

    Energy Technology Data Exchange (ETDEWEB)

    Gonzalez-Pradas, E.; Villafranca-Sanchez, M.; Urena-Amate, M.D. (Univ. of Almeria (Spain). Dept. of Inorganic Chemistry); Del Rey-Bueno, F.; Garcia-Rodriguez, A. (Univ. of Granada (Spain). Dept. of Inorganic Chemistry)

    To evaluate the potential use of two montmorillonite-(Ce or Zr) phosphate crosslinked compounds in removing organic pollutants such as aniline, p-toluidine, and p-acetylaniline from water, adsorption experiments were performed under conditions of varied temperature (288 and 308 K). Adsorption on the montmorillonite-Ce-phosphate compound was best described by a hyperbolic (H-type) isotherm, whereas for the montmorillonite-Zr-phosphate compound, S-type isotherms were obtained for p-toluidine and aniline and L-type for p-acetylaniline. Amines adsorption increases with increasing temperature on the cerium crosslinked material, while for the zirconium-crosslinked compound, adsorption decreases as temperature increases from 288 to 308 K, possibly due to a mainly physical process. Fourier-transform infrared (FTIR) spectroscopy indicated that at the pH generated by the adsorbents, the protonated species of these amines plays an important role in the adsorption process. X-ray diffraction analysis showed that the aromatic amines are intercalated into the adsorbents. For any given amine, the cerium-montmorillonite adsorbent shows a higher capacity of adsorption compared with zirconium-montmorillonite adsorbent, so it might be reasonably used in removing aromatic amines from water.

  1. Molecular Simulation Study of Montmorillonite in Contact with Variably Wet Supercritical Carbon Dioxide

    KAUST Repository

    Kadoura, Ahmad Salim

    2017-03-07

    We perform grand canonical Monte Carlo simulations to study the detailed molecular mechanism of intercalation behavior of CO2 in Na-, Ca-, and Mg- montmorillonite exposed to variably hydrated supercritical CO2 at 323.15 K and 90 bar, The simulations indicate that the intercalation of CO2 strongly depends on the relative humidity (RH). The intercalation of CO2 in the dehydrated interlayer is inhibited, followed by the swelling of the interlayer region due to uptake of water and CO2 as the RH increases. In all of the hydrated clay samples, the amount of the intercalated CO2 generally decreases as a function of increasing RH, which is attributed mainly to the weakening of the interaction between CO2 and clay. At low RH values, Ca- and Mg- montmorillonite are relatively more efficient in capturing CO2. The amount of CO2 trapped in all clay samples shows similar values above RH of similar to 60%. Molecular dynamics simulations show that the diffusion coefficient of each species generally increases with increasing RH due to the associated expansion of the interlayer distance of the clay. For all the hydrated samples, the diffusion coefficients of CO2 and water in the interlayers are mostly comparable due to the fact that CO2 molecules are well solvated. The diffusion of CO2 in each hydration state is mostly independent of the type of cation in accordance with the fact that CO2 molecules hardly migrate into the first hydration shell of the interlayer cations.

  2. Comparative Effects of MMT Clay Modified with Two Different Cationic Surfactants on the Thermal and Rheological Properties of Polypropylene Nanocomposites

    Directory of Open Access Journals (Sweden)

    Meshal Al-Samhan

    2017-01-01

    Full Text Available Polypropylene montmorillonite (MMT nanocomposites were prepared by melt blending using two different organoclays modified with imidazolium and alkylammonium surfactants. The imidazolium and ammonium modified organoclays were characterized by the FTIR and SEM analysis. The effect of organic clay (MMT on the physical properties of polypropylene was evaluated, thermal and rheological properties with different filler weight percentage. Differential scanning calorimetric results showed that imidazolium modified clay (IMMT exhibits low melting temperature compared to the ammonium modified clay (AMMT. The crystallinity analysis showed that crystallization improved in all nanocomposites irrespective of surface modification; the thermogravimetric analysis showed that the imidazolium modified polymer composites are more thermally stable than conventional ammonium modified composites. The Transmission Electron Microscopy (TEM analyses indicated that the PP-IMMT composites displayed exfoliated morphologies compared with the intercalated structure in PP-AMMT, and the rheological analysis at 180°C showed an enhancement in the viscoelastic properties as the clay concentration increases. The melt viscosity, crossover modulus, and relaxation times were comparable for both the surface modified composites with two different cations. The imidazolium based surfactant was found to be an effective organic modification for MMT to prepare thermally stable PP/MMT nanocomposites.

  3. Effect of Textured Surfactant Brushes on Polymer-Layered Silicate Nanocomposite Morphology

    Science.gov (United States)

    2004-02-01

    melt processing a mixture of stearylammonium-exchanged montmorillonite, maleic anhydride -modified polypropylene oligomer, and homopolypropylene (29–31...molecular weights was performed using both the XMASS (Bruker) and Polymerix (Sierra Analytics) software packages. Surfactant nomenclature and...properties are recorded in table 1. The nomenclature used is such that for any surfactant it provides information about its approximate molecular weight

  4. Preparation of PAA/AM/MMT Hybrid by Intercalation Polymerization

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    @@ Over the last few years, Montmorillonite (MMT) was widely used as a special inorganic material for preparing Polymer/MMT nanocompsites. MMT is a clay imineral consisting of stacked silicate sheets whose thickness is about 10A. Through intercalation a large number of polymer-clay nanocomposites have been prepared such as Nylon-clay hybrid [1], PS-clay hybrid [2], Poly (methyl methacrylate) (PMMA)-clay hybrid [3], etc. In this article, the synthesis and properties of Poly (acrylic acid/acrylamide)/MMT hybrid (PAAAM/MMT) were studied. X-ray diffraction and Transmission electron microscopy were used to characterize the hybrid material. DSC has been used to study its property. Results showed that the intercalating reagents have entered the space of MMT's layers and enlarged them. At the same time, the MMT dispersed homogeneously in acrylic acid and acrylamide monomers that allow MMT to disperse in PAAAM matrix in the monolayer form.

  5. Montmorillonite/Poly (L-Lactide microcomposite spheres as reservoirs of antidepressant drugs and their controlled release property

    Directory of Open Access Journals (Sweden)

    Shalini Rajkumar

    2015-10-01

    Full Text Available This work evaluates intercalation of Nortriptyline (NT and Venlafaxine (VFX in an interlayer gallery of Na+-MMT (Montmorillonite, which was further compounded with Poly (L-Lactide (PLLA to form microcomposite spheres (MPs for oral controlled drug delivery. The XRD patterns, thermal and spectroscopic analyses indicated intercalation of drugs into the MMT interlayer that was stabilized by electrostatic interaction. No significant changes in structural and functional properties of drugs were found in the MMT layers. In vitro drug release studies showed controlled release pattern.

  6. Characterization of synthesized polyurethane/montmorillonite nanocomposites foams

    Science.gov (United States)

    Ansari, Farahnaz; Sachse, Sophia; Michalowski, S.; Kavosh, Masoud; Pielichowski, Krzysztof; Njuguna, James

    2014-08-01

    Nanophased hybrid composites based on polyurethane/montmorillonite (PU/MMT) have been fabricated. The nanocomposite which was formed by the addition of a polyol premix with 4,4'-diphenylmethane diisocyanate to obtain nanophased polyurethane foams which were then used for fabrication of nanocomposite panels has been shown to have raised strength, stiffness and thermal insulation properties. The nanophased polyurethane foam was characterized by means of scanning electron microscope (SEM), transmission electron microscope (TEM) measurements and X-ray diffraction (XRD). TEM and SEM analysis indicated that nanophased particles are dispersed homogeneously in the polyurethane matrix on the nanometer scale indicating that PU/MMT is an intercalated nanocomposite with a 2-3 nm nanolayer thickness.

  7. Theoretical characterization of formamide on the inner surface of montmorillonite

    Science.gov (United States)

    Shi, Jing; Lou, Zhaoyang; Yang, Mingli; Zhang, Yao; Liu, Houbin; Meng, Yingfeng

    2014-06-01

    Density functional theory calculations were performed to characterize the low-lying structures of formamide (FA) and protonated formamide (FAH) in the interlayer space of montmorillonite (MMT). The interactions among FA/FAH, H2O, Na+, and the inner surface of MMT were systematically analyzed. The carbonyl-O of FA/FAH has strong coulomb interaction with Na+, while its amide-H forms hydrogen bonds (HBs) with water and MMT surface. The adsorption of FA is promoted by H2O, which exhibits a cooperative adsorption effect by enhancing the FA-Na+ coulomb interaction and by forming HBs with FA. Our study reveals the structural basis of FA/FAH as an intercalator for MMT splitting.

  8. Montmorillonite Poly-L-lactide microcomposites of procainamide for controlled drug delivery: In vitro and in vivo evaluation

    Directory of Open Access Journals (Sweden)

    B B Kevadiya

    2013-01-01

    Full Text Available The research work reported in this paper is extension of our previous findings related to intercalation of procainamide hydrochloride, an antiarrythmia drug in interlayer gallery of Na + -clay (montmorillonite. The microcomposite particles prepared from procainamide-montmorillonite hybrid and poly L-lactide were characterised by scanning electron microscope and atomic force microscopy analysis. In vitro drug release study in simulated intestinal fluid showed controlled release pattern up to ~72 h and significant reduction in the drug release in gastric environment. In vivo pharmacokinetics and biodistribution in rats showed that the plasma/tissue drug levels were within therapeutic window as compared with free drug. The data from toxicity biomarker estimations and clinical biochemistry/haematological parameters showed significant reduction in drug toxicity when formulated in montmorillonite/poly L-lactide as compared with free drug, which is of considerable value in achieving improved therapy with reduced side effects.

  9. Improvement of the barrier properties of Nafion(R) by fluoro-modified montmorillonite

    Energy Technology Data Exchange (ETDEWEB)

    Thomassin, Jean-Michel; Pagnoulle, Christophe; Jerome, Robert [Center for Education and Research on Macromolecules (CERM), University of Liege, Sart-Tilman, B6, B-4000 Liege (Belgium); Bizzari, Didier; Caldarella, Giuseppe; Germain, Albert [Laboratoire de Chimie Industrielle, Institut de Chimie B6, University of Liege, Sart Tilman, B-4000 Liege (Belgium)

    2006-05-15

    Montmorillonite (MMT) was modified by two types of cationic fluorosurfactants in order to improve compatibility with and dispersion within Nafion(R) membranes. Perfluoropolyether-containing cationic surfactant improved efficiency, by improving the barrier properties of Nafion(R) towards methanol. Moreover, the fluoro-modified MMT had no deleterious impact on the ionic conductivity of the membranes in contrast to conventional organo-modified MMT. The performances of a small size fuel cell were accordingly improved. (author)

  10. Silver bromide in montmorillonite as visible light-driven photocatalyst and the role of montmorillonite

    Science.gov (United States)

    Sohrabnezhad, Sh.; Pourahmad, A.; Razavi, M.

    2016-09-01

    In this study, novel plasmonic photocatalyst, Ag/AgBr-montmorillonite (MMT) nanocomposite, was prepared by dispersion method and light irradiation. The structure, composition and optical properties of such material was investigated by transmission electron microscopy, UV-visible diffuse reflectance spectroscopy, X-ray diffraction and Fourier transform infrared spectroscopy. The powder X-ray diffraction showed intercalation of Ag/AgBr nanoparticles into the clay interlayer space. The results showed that the prepared sample has a similar phase composition. However, their photocatalytic activity varied significantly. The photocatalytic testing result showed that the Ag/AgBr-MMT nanocomposite was more efficient photocatalyst in the discoloration of methylene blue under visible light illumination. The Ag/AgBr-MMT nanocomposite in pH = 2 and under visible light degraded 92 % of dye at the irradiation time of 20 min. MMT as matrix showed excellent role in separation efficiency of electron-hole pairs. The mechanism of separation of the photogenerated electrons and holes at the Ag/AgBr-MMT nanocomposite was discussed.

  11. Thin flexible intercalation anodes

    Energy Technology Data Exchange (ETDEWEB)

    Levy, S.C.; Cieslak, W.R.; Klassen, S.E.; Lagasse, R.R.

    1994-10-01

    Poly(acrylonitrile) fibers have been pyrolyzed under various conditions to form flexible carbon yarns capable of intercalating lithium ions. These fibers have also been formed into both woven and non woven cloths. Potentiostatic, potentiodynamic and galvanostatic tests have been conducted with these materials in several electrolytes. In some tests, a potential hold was used after each constant current charge and discharge. These tests have shown some of these flexible materials to reversibly intercalate lithium ions to levels that are suitable for use as a practical battery anode.

  12. Graphite intercalation compounds and applications

    CERN Document Server

    Enoki, Toshiaki; Endo, Morinobu

    2003-01-01

    1. Introduction. 2. Synthesis and Intercalation Chemistry. 3. Structures and Phase Transitions. 4. Lattice Dynamics. 5. Electronic Structures. 6. Electron Transport Properties. 7. Magnetic Properties. 8. Surface Properties and Gas Adsorption. 9. GICs and Batteries. 10. Highly Conductive Graphite Fibers. 11. Exfoliated Graphite Formed by Intercalation. 12. Intercalated Fullerenes and Carbon Nanotubes. Index

  13. Adsorption and interaction of 5-fluorouracil with montmorillonite and saponite by FT-IR spectroscopy

    Science.gov (United States)

    Akalin, Elif; Akyuz, Sevim; Akyuz, Tanil

    2007-05-01

    Adsorption of 5-fluorouracil (5-FU) on montmorillonite and saponite has been investigated using FT-IR spectrometry. The intercalation of 5-FU within montmorillonite or saponite has been shown by X-ray diffraction to increase the interlayer spacing. In order to investigate interaction of 5-FU with clays, the harmonic and anharmonic vibrational wavenumbers of free 5-FU and 5-FU interacting with Al(OH) 3 have been calculated at the DFT/B3LYP level with 6-31++G(d,p) basis set by using Gaussian 03 program set. The solution effect on 5-FU was also calculated by using polarizable continuum model (PCM). Experimental and calculated results indicated that 5-FU interacted with clays by direct or indirect coordination (through water molecules) to the Lewis acidic centers.

  14. Preparation and Structure of Poly(ethylene-co-vinylacetate)/Montmorillonite Nanocomposites

    Institute of Scientific and Technical Information of China (English)

    HUANG Li-qian

    2009-01-01

    Poly(ethylene-co-vinylacetate)/sodium montmorillonite (EVA/MMT) and Poly (ethylene-co-vinylacetate)/arganophilic montmorillonite (EVA/o-MMT) nanocomposite were prepared by solid-state mixing. The morphology and structure of the composites were explored by scanning electron microscopy (SEM),wide-angle X-ray diffraction (WAXD ), differential scanning calorimetry (DSC), and dynamic mechanical analysis (DMA).The results showed that the intercalated nanocomposite was successfully synthesized for EVA/o-MMT system, while in the EVA/MMT nanocomposite, MMT were poorly dispersed in the order of urn. An unexpected rubbery plateau modulus of EVA/o-MMT nanocomposite above melting point of EVA was explored by DMA. The possible origins of this high-temperature modulus were analyzed.

  15. Intercalation Assembly Method and Intercalation Process Control of Layered Intercalated Functional Materials

    Institute of Scientific and Technical Information of China (English)

    LI Kaitao; WANG Guirong; LI Dianqing; LIN Yanjun; DUAN Xue

    2013-01-01

    Layered intercalated functional materials of layered double hydroxide type are an important class of functional materials developed in recent years.Based on long term studies on these materials in the State Key Laboratory of Chemical Resource Engineering in Beijing University of Chemical Technology,the principle for the design of controlled intercalation processes in the light of future production processing requirements has been developed.Intercalation assembly methods and technologies have been invented to control the intercalation process for preparing layered intercalated materials with various structures and functions.

  16. Avaliação de derivados poliméricos intercalados em montmorilonita organofílica na preparação de novos materiais de uso farmacêutico Evaluation of use of organophilic montmorillonite and its polymeric intercalated derivatives in preparation of new pharmaceutical materials

    Directory of Open Access Journals (Sweden)

    Camila B. Dornelas

    2008-09-01

    Full Text Available A nanotecnologia está relacionada às estruturas, propriedades e processos envolvendo materiais com dimensões numa escala nanométrica. O conceito de nanotecnologia em aplicações farmacêuticas, mais especificamente na liberação de fármacos, está baseado na produção de nanopartículas que contêm moléculas do fármaco a serem depositadas exclusivamente no órgão ou tecido alvo com a vantagem de serem inativas. Neste contexto, o presente trabalho busca estudar a utilização de uma organoargila, previamente modificada com octadecilamina, viscogel B8, como matriz de liberação controlada de fármacos por meio da reação de intercalação desta argila com PEG 6000 e MEG, comparando-se os resultados obtidos com um derivado previamente obtido da intercalação desta argila com PVP K-30. Estes materiais têm como diferencial a reunião de diferentes aspectos de funcionalidade, possibilitando se obter excipientes de liberação modificada de propriedades mistas.Nanotechnology is related to structures, properties and processes involving materials in a nanometer dimension. This is widely used for pharmaceutical applications, more specifically in drugs' release. In this context, the present work studies the use of organophilic montmorillonite (OMMT, viscogel B8, as matrix of controlled release of drugs. New polymer-layered silicate nanocomposites (PLN of MEG, PEG 6000 and OMMT were prepared and compared with PVP K-30-OMMT.

  17. Modification of nano-sized layered double hydroxides by long-chain organic aliphatic surfactants

    Directory of Open Access Journals (Sweden)

    RAMASAMY ANBARASAN

    2008-03-01

    Full Text Available The inter-layer anion of layered double hydroxides (LDH with a hydrotalcite (HT-like structure was ion-exchanged with various organic surfactants, particularly with long chain aliphatic surfactants. After the ion-exchange process, the basal spacing of the LDH was increased and the increase of the basal spacing depended on various factors, such as the intercalation capacity functionality and orientation capability of the surfactant. Of the employed surfactants, stearic acid intercalated LDH showed the highest increase of the basal spacing, which was confirmed by XRD analysis. FTIR results supported the interaction of the surfactants with the LDH. In addition, an increase in the thermal stability of the dodecanedioic acid intercalated HT was evidenced by the TGA method.

  18. Comparison Study on the Effect of Interlayer Hydration and Solvation on Montmorillonite Delamination

    Science.gov (United States)

    Li, Hongliang; Song, Shaoxian; Zhao, Yunliang; Nahmad, Yuri; Chen, Tianxing

    2016-11-01

    The effect of water and isopropanol intercalation on montmorillonite (MMT) delamination was investigated in order to compare the roles of hydration and solvation in the delamination. Transmittance results showed that water has a significant effect on the delamination of MMT compared with isopropanol. This observation was attributed to the difference of the intercalation of water and isopropanol. Thermogravimetric (TG) results illustrate that the intercalation mass of water was greater than that of isopropanol when the pressure remained constant. Weighing test results show that the intercalation mass of water was smaller than that of isopropanol when the volume of MMT remained constant. Molecule dynamic simulation results show that the water and isopropanol molecules were interacting with Na+ and siloxane surface of MMT, respectively. It was demonstrated that the hydration of the MMT interlayer followed two steps: in step 1, the Na+ in the interlayer was hydrated, thereby expanding the interlayer spacing; in step 2, additional water molecules were absorbed into the expanded interlayer space. It was found that step 2 could not be actuated until the completion of step 1. For the solvation of the MMT interlayer with isopropanol, however, only one step was required, in which isopropanol was absorbed onto the siloxane sites of the interlayer while maintaining the interlayer spacing.

  19. Biodegradable gelatin-ciprofloxacin-montmorillonite composite hydrogels for controlled drug release and wound dressing application.

    Science.gov (United States)

    Kevadiya, Bhavesh D; Rajkumar, Shalini; Bajaj, Hari C; Chettiar, Shiva Shankaran; Gosai, Kalpeshgiri; Brahmbhatt, Harshad; Bhatt, Adarsh S; Barvaliya, Yogesh K; Dave, Gaurav S; Kothari, Ramesh K

    2014-10-01

    This work reports intercalation of a sparingly soluble antibiotic (ciprofloxacin) into layered nanostructure silicate, montmorillonite (MMT) and its reaction with bone derived polypeptide, gelatin that yields three-dimensional composite hydrogel. Drug intercalation results in changes in MMT layered space and drug loaded MMT and gelatin creates 3D morphology with biodegradable composite hydrogels. These changes can be correlated with electrostatic interactions between the drug, MMT and the gelatin polypeptides as confirmed by X-ray diffraction patterns, thermal, spectroscopic analyses, computational modeling and 3D morphology revealed by SEM and TEM analysis. No significant changes in structural and functional properties of drug was found after intercalation in MMT layers and composite hydrogels. In vitro drug release profiles showed controlled release up to 150h. The drug loaded composite hydrogels were tested on lung cancer cells (A549) by MTT assay. The results of in vitro cell migration and proliferation assay were promising as composite hydrogels induced wound healing progression. In vitro biodegradation was studied using proteolytic enzymes (lysozyme and protease K) at physiological conditions. This new approach of drug intercalation into the layered nanostructure silicate by ion-exchange may have significant applications in cost-effective wound dressing biomaterial with antimicrobial property.

  20. Effects of thermal history in the ring opening polymerization of CBT and its mixtures with montmorillonite on the crystallization of the resulting poly(butylene terephthalate)

    Energy Technology Data Exchange (ETDEWEB)

    Lanciano, Giuseppina [Department of Innovation Engineering, University of Salento, Via per Arnesano, 73100 Lecce (Italy); Greco, Antonio, E-mail: antonio.greco@unile.it [Department of Innovation Engineering, University of Salento, Via per Arnesano, 73100 Lecce (Italy); Maffezzoli, Alfonso [Department of Innovation Engineering, University of Salento, Via per Arnesano, 73100 Lecce (Italy); Mascia, Leno [Department of Materials, Loughborough University, Loughborough, LE 11 3TU (United Kingdom)

    2009-09-10

    Differential scanning calorimetry was used to study the thermal characteristics and morphological structure of species produced during the ring opening polymerization of cyclic butylene terephthalate (CBT). Thermal programs consisting of a first ramp heating scan and an isothermal step, followed by cooling and a second ramp heating step, were used to study the effects of thermal history, catalyst (butyl chlorotin dihydroxide) at concentrations between 0.1 and 1.3% (w/w), and the presence of a layered silicate nanofiller (montmorillonite at 4.0%, w/w) on the structure of the resulting polymer (poly(butylene terephthalate), pCBT). Wide angle X-ray diffraction was used to monitor the degree of exfoliation of the nanocomposites. It was found that pCBT is formed in the amorphous state, and crystallizes during the heating step or during the isothermal step at temperatures lower than the equilibrium melting temperature of the polymer (T{sub m}{sup 0}). When premixed with the nanofiller, irrespective of whether this was previously intercalated with a tallow surfactant or used in its pristine form, polymerization took place at higher temperatures and most of the crystallization was found to occur during the cooling stage. In those cases where crystallization took place during either the first heating scan, or during a prolonged isothermal step below the T{sub m}{sup 0} of the polymer, the resulting crystals were found to have a higher lamellar thickness, as compared with the same polymer crystallized from the melt during the cooling step from temperatures above the polymer T{sub m}{sup 0}.

  1. Functional properties of extruded nano composites based on cassava starch, polyvinyl alcohol and montmorillonite; Propriedades funcionais de nanocompositos extrusados de amido de mandioca, alcool polivinilico e montmorilonita

    Energy Technology Data Exchange (ETDEWEB)

    Debiagi, Flavia; Mali, Suzana [Departamento de Bioquimica e Biotecnologia, Universidade Estadual de Londrina, PR (Brazil)

    2011-07-01

    The objectives of this work were to produce expanded nano composites (foams) based on starch, PVA and sodium montmorillonite and characterize them according to their expansion index (EI), density, water absorption capacity (WSC), mechanical properties and X-ray diffraction. The nano composites were prepared in a single-screw extruder using different starch contents (97.6 - 55.2 g/100 g formulation), PVA (0 - 40 g/100 g formulation), unmodified nano clay - Closite - Na (0 - 4. 8 g/100 g formulation) and glycerol (20 g/100 g formulation) as plasticizer. The addition of montmorillonite and PVA resulted in an increase of EI and a decrease of density of the samples, and reduced WSC and increased the mechanical strength of the foams. Through the analysis of X-ray diffraction can be observed that the addition of montmorillonite led to production of intercalated nano composites in all samples. (author)

  2. Nanocomposites of rice and banana flours blend with montmorillonite: Partial characterization

    Energy Technology Data Exchange (ETDEWEB)

    Rodríguez-Marín, María L.; Bello-Pérez, Luis A. [Centro de Desarrollo de Productos Bióticos, Instituto Politécnico Nacional, Km 6 carr Yautepec-Jojutla, Calle Ceprobi No. 8, Colonia San Isidro, Apartado Postal 24, C.P 62731, Yautepec, Morelos (Mexico); Yee-Madeira, Hernani [Departamento de Física, Escuela Superior de Física y Matemáticas-IPN, Edificio 9, U.P., ‘Adolfo López Mateos’ Col. Lindavista, C.P. 07738, México, D. F. (Mexico); Zhong, Qixin [Department of Food science and Technology, the University of Tennessee, Knoxville (United States); González-Soto, Rosalía A., E-mail: rsoto@ipn.mx [Centro de Desarrollo de Productos Bióticos, Instituto Politécnico Nacional, Km 6 carr Yautepec-Jojutla, Calle Ceprobi No. 8, Colonia San Isidro, Apartado Postal 24, C.P 62731, Yautepec, Morelos (Mexico)

    2013-10-15

    Rice and banana flours are inexpensive starchy materials that can form films with more improved properties than those made with their starch because flour and starch present different hydrophobicity. Montmorillonite (MMT) can be used to further improve the properties of starch-based films, which has not received much research attention for starchy flours. The aim of this work was to evaluate the mechanical and barrier properties of nanocomposite films of banana and rice flours as matrix material with addition of MMT as a nanofiller. MMT was modified using citric acid to produce intercalated structures, as verified by the X-ray diffraction pattern. The intercalated MMT was blended with flour slurries, and films were prepared by casting. Nanocomposite films of banana and rice flours presented an increase in the tensile at break and elongation percentage, respectively, more than their respective control films without MMT. This study showed that banana and rice flours could be alternative raw materials to use in making nanocomposite films. - Highlights: • Flour films presented adequate mechanical and barrier properties. • Addition of montmorillonite modified the mechanical and barrier properties of flour films. • The mechanical properties of the films were influenced by the different components of the flours. • The fiber of the banana flour improved the mechanical properties of the films.

  3. Comparison of Effects of Different Organo-montmorillonites on PA 66/ Clay Nanocomposites

    Institute of Scientific and Technical Information of China (English)

    HE Su-qin; GUO Jian-guo; KANG Xin; DU Pin; ZHU Cheng-shen

    2005-01-01

    Different organo-montmorillonites (OMMTs) are preparedby modifying montmorillonites (MMTs) with CTAB, PA1010 salts/CTAB, PEG/CTAB, PVA/CTAB, PVP, PVP/CTAB and PA 6/CTAB, respectively. These OMMTs were studied by X-ray diffraction and TG. The gallery sizes of them are all larger than that of sodium MMTs. And the decomposition temperatures of them are all much higher than that of MMT and the processing temperature of PA 66,especially OM- 6 and OM- 7, the decomposition temperatures of which are 451.6℃ and 439.1℃, almost the collapse temperature of the native MMT crystal lattice which is more than 500℃. Then PA 66/Clay nanocomposites were synthesized by mixing these OMMTs with PA 66 matrix via melt intercalation. Experimental results indicate that the tensile and flexural properties increase significantly,especially those of PCN - 08. The combination property of PCN- 08 is the best. TEM photos show that some clay platelets are present in the matrix as exfoliated layers, while most of the clay platelets are present as intercalated layers.

  4. Highly anisotropic conductivity of tablets pressed from polyaniline-montmorillonite nanocomposite

    Energy Technology Data Exchange (ETDEWEB)

    Tokarský, Jonáš, E-mail: jonas.tokarsky@vsb.cz [Nanotechnology centre, VŠB-TU Ostrava, 17. listopadu 15/2172, 708 33 Ostrava—Poruba (Czech Republic); IT4Innovations Centre of Excellence, VŠB-TU Ostrava, 17. listopadu 15/2172, 708 33 Ostrava—Poruba (Czech Republic); Kulhánková, Lenka [Faculty of Metallurgy and Materials Engineering, VŠB-TU Ostrava, 17. listopadu 15/2172, 708 33 Ostrava—Poruba (Czech Republic); Neuwirthová, Lucie; Mamulová Kutláková, Kateřina [Nanotechnology centre, VŠB-TU Ostrava, 17. listopadu 15/2172, 708 33 Ostrava—Poruba (Czech Republic); Vallová, Silvie [Faculty of Metallurgy and Materials Engineering, VŠB-TU Ostrava, 17. listopadu 15/2172, 708 33 Ostrava—Poruba (Czech Republic); Stýskala, Vítězslav [Faculty of Electrical Engineering and Computer Science, VŠB-TU Ostrava, 17. listopadu 15/2172, 708 33 Ostrava—Poruba (Czech Republic); Čapková, Pavla [Faculty of Science, University of J.E. Purkyně, České mládeže 8, 400 96 Ústí nad Labem (Czech Republic)

    2016-03-15

    Highlights: • Montmorillonite (MMT) can be intercalated with polyaniline (PANI) chains. • Tablets pressed from PANI/MMT exhibit high anisotropy in electrical conductivity. • Pressure 28MPa is sufficient to reach the anisotropy. • Tablets pressed from pure PANI also exhibit anisotropy in electrical conductivity. - Abstract: Polyaniline-montmorillonite nanocomposite was prepared from anilinium sulfate (precursor) and ammonium peroxodisulfate (oxidizing agent) using simple one-step method. The resulting nanocomposite obtained in powder form has been pressed into tablets using various compression pressures (28–400 MPa). Electrical conductivities of tablets in two perpendicular directions, i.e. direction parallel with the main surface of tablet (σ=) and in orthogonal direction (σ⊥), and corresponding anisotropy factors (i.e., the ratio σ=/σ⊥) have been studied in dependence on compression pressure used during the preparation. Polyaniline-montmorillonite nanocomposite was characterized using X-ray diffraction analysis, raman spectroscopy, transmission electron microscopy, thermogravimetric analysis and molecular modeling which led to the understanding of the internal structure. Measurement of hardness performed on pressed tablets has been also involved. Taking into account the highest value of anisotropy factor reached (σ=/σ⊥ = 490), present study shows a chance to design conductors with nearly two-dimensional conductivity.

  5. Study of antibacterial activity of Ag and Ag2CO3 nanoparticles stabilized over montmorillonite.

    Science.gov (United States)

    Sohrabnezhad, Sh; Pourahmad, A; Mehdipour Moghaddam, M J; Sadeghi, A

    2015-02-05

    Silver carbonate and silver nanoparticles (NPs) over of stabilizer montmorillonite (MMT) have been synthesized in aqueous and polyol solvent, respectively. Dispersions of silver nanoparticles have been prepared by the reduction of silver nitrate over of MMT in presence and absence of Na2CO3 compound in ethylene glycol. It was observed that montmorillonite was capable of stabilizing formed Ag nanoparticles through the reduction of Ag(+) ions in ethylene glycol. Na2CO3 was used as carbonate source in synthesis of Ag2CO3 NPs in water solvent and also for controlling of Ag nanoparticles size in ethylene glycol medium. The samples were characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), transmission electron microscopy (TEM), and ultraviolet-visible diffuse reflectance spectroscopy (DRS). The TEM images showed that Ag NPs size in presence Na2CO3 salts was smaller than without that. The results indicated intercalation of Ag and Ag2CO3 nanoparticles into the montmorillonite clay layers. The diffuse reflectance spectra exhibited a strong surface plasmon resonance (SPR) adsorption peak in the visible region, resulting from Ag nanoparticles. The antibacterial testing results showed that the Ag2CO3-MMT nanocomposite exhibited an antibacterial activity higher than Ag-MMT sample against Escherichia coli.

  6. Stacking interactions and DNA intercalation

    Energy Technology Data Exchange (ETDEWEB)

    Li, Dr. Shen [Fred Hutchinson Cancer Research Center; Cooper, Valentino R [ORNL; Thonhauser, Prof. Timo [Wake Forest University, Winston-Salem, NC; Lundqvist, Prof. Bengt I. [Chalmers University of Technology, Sweden; Langreth, David C. [Rutgers University

    2009-01-01

    The relationship between stacking interactions and the intercalation of proflavine and ellipticine within DNA is investigated using a nonempirical van der Waals density functional for the correlation energy. Our results, employing a binary stack model, highlight fundamental, qualitative differences between base-pair base-pair interactions and that of the stacked intercalator base pair system. Most notable result is the paucity of torque which so distinctively defines the Twist of DNA. Surprisingly, this model, when combined with a constraint on the twist of the surrounding base-pair steps to match the observed unwinding of the sugar-phosphate backbone, was sufficient for explaining the experimentally observed proflavine intercalator configuration. Our extensive mapping of the potential energy surface of base-pair intercalator interactions can provide valuable information for future nonempirical studies of DNA intercalation dynamics.

  7. Synthesis and characterization of a novel chitosan/montmorillonite/hydroxyapatite nanocomposite for bone tissue engineering

    Energy Technology Data Exchange (ETDEWEB)

    Katti, Kalpana S; Katti, Dinesh R; Dash, Rajalaxmi [Department of Civil Engineering, North Dakota State University, Fargo, ND 58105 (United States)], E-mail: Kalpana.katti@ndsu.edu

    2008-09-01

    Recently, biopolymer-based nanocomposites have been replacing synthetic polymer composites for various biomedical applications. This is often because of the biocompatible and biodegradable behavior of natural polymers. Several studies have been reported pertaining to the synthesis and characterization of chitosan(chi)/montmorillonite(MMT) and chitosan (chi)/hydroxyapatite (HAP) for tissue engineering applications. In the present work, a biopolymer-based novel nanocomposite chitosan/montmorillonite (MMT)/hydroxyapatite (HAP) was developed for biomedical applications. The composite was prepared from chitosan, unmodified MMT and HAP precipitate in aqueous media. The properties of the composites were investigated using x-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), atomic force microscopy (AFM) and thermogravimetric analysis (TGA). Nanomechanical properties were measured using nanoindentation. Cell culture experiments were also conducted in order to ascertain the biocompatibility of the composite. The XRD results indicate that an intercalated structure was formed with an increase in d-spacing of montmorillonite. FTIR studies provide the evidence of molecular interaction among the three different constituents of the composite. AFM images show well-distributed nanoparticles in the chitosan matrix. The composites also exhibit a significant enhancement in nanomechanical property as compared to pure chitosan as well as the chi/HAP and chi/MMT composites. The TGA results indicate that an intercalated nanocomposite was formed with improved thermal properties even compared to chi/MMT composites. The results of cell culture experiments show that the composite is biocompatible and has a better cell proliferation rate compared to chi/HAP composites. This work represents the design of a novel clay-chitosan-hydroxyapatite composite with improved mechanical properties that has potential applications in bone tissue engineering.

  8. Switchable Surfactants

    National Research Council Canada - National Science Library

    Yingxin Liu; Philip G. Jessop; Michael Cunningham; Charles A. Eckert; Charles L. Liotta

    2006-01-01

    .... We report that long-chain alkyl amidine compounds can be reversibly transformed into charged surfactants by exposure to an atmosphere of carbon dioxide, thereby stabilizing water/alkane emulsions...

  9. Preservation of glutamic acid-iron chelate into montmorillonite to efficiently degrade Reactive Blue 19 in a Fenton system under sunlight irradiation at neutral pH

    Energy Technology Data Exchange (ETDEWEB)

    Huang, Zhujian [College of Natural Resources and Environment, South China Agricultural University, Guangzhou 510642 (China); Wu, Pingxiao, E-mail: pppxwu@scut.edu.cn [School of Environment and Energy, South China University of Technology, Guangzhou Higher Education Mega Centre, Guangzhou 510006 (China); The Key Lab of Pollution Control and Ecosystem Restoration in Industry Clusters, Ministry of Education, Guangzhou 510006 (China); Gong, Beini; Yang, Shanshan; Li, Hailing [School of Environment and Energy, South China University of Technology, Guangzhou Higher Education Mega Centre, Guangzhou 510006 (China); Zhu, Ziao; Cui, Lihua [College of Natural Resources and Environment, South China Agricultural University, Guangzhou 510642 (China)

    2016-05-01

    Graphical abstract: - Highlights: • G–Fe chelate molecules were well preserved into montmorillonite. • The product shows an excellent catalytic activity under sunlight at neutral pH value. • G–Fe–Mt is a promising catalyst for advanced oxidation processes. - Abstract: To further enhance the visible light responsive property and the chemical stability of Fe/clay mineral catalysts, glutamic acid-iron chelate intercalated montmorillonite (G–Fe–Mt) was developed. The physiochemical properties of G–Fe–Mt were investigated by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), UV–vis diffuse reflectance spectroscopy (DRS), etc. The results showed that glutamic acid-iron chelates were successfully intercalated into the gallery of montmorillonite and the intercalated glutamic acid-iron chelate molecules were well preserved. The product G–Fe–Mt displayed excellent catalytic performance in heterogeneous photo-Fenton reaction under sunlight irradiation at acidic and neutral pH values. The chelation and the visible light responsiveness of glutamic acid produce a synergistic effect leading to greatly enhanced sunlight-Fenton reaction catalyzed by the heterogeneous G–Fe–Mt under neutral pH. G–Fe–Mt is a promising catalyst for advanced oxidation processes.

  10. Preparation of montmorillonite modified phenolic resin for shell process

    Institute of Scientific and Technical Information of China (English)

    Xiong Jianmin; Li Yuancai; Wang Wenqing; Xia Chun

    2009-01-01

    The development of montmodllonite modified phenolic resin under microwave irradiation heating was investigated. The effect of montmorillonite content and stirring time on the structure and morphology of synthetic resin was analyzed. The optimum processing procedure was found to be 45 rain stirring time with 5.4% montmorillonite addition. Further, the platelet spacing increases with stirring time till montmorillonite exfoliated to nanoscales platelet. When montmorillonite is exfoliated, layered structure at nanoscale can be uniformly distributed in the resin. The overall performance of montmorillonite modified phenolic resin is improved remarkably, such as flow ability, tensile strength and toughness property of resin coated sand. However, the gelation speed decreased slightly by adding montmorillonite.

  11. A comparative study and evaluation of sulfamethoxazole adsorption onto organo-montmorillonites

    Institute of Scientific and Technical Information of China (English)

    Laifu Lu; Manglai Gao; Zheng Gu; Senfeng Yang; Yuening Liu

    2014-01-01

    Three organo-montmorillonites were prepared using surfactants,and their adsorption behaviors toward sulfamethoxazole (SMX) were investigated.The surfactants used were cetyltrimethyl ammonium bromide (CTMAB),3-(N,N-dimethylhexadecylammonio) propane sulfonate (HDAPS) and 1,3-bis(hexadecyldimethylammonio)-propane dibromide (BHDAP).The properties of the organo-montmorillonites were characterized by X-ray diffraction,scanning electron microscopy and N2 adsorption-desorption isotherm measurements.Results showed that the interlayer spacing of montmorillonite was increased and the surface area as well as the morphology were changed.Batch adsorption experiments showed that the surfactant loading amount had a great effect on the adsorption of SMX.The adsorption process was pH dependent and the maximum adsorption capacity was obtained at pH 3 for HDAPS-Mt,while CTMAB-Mt and BHDAP-Mt showed a high removal efficiency at 3-11.The adsorption capacity increased with the initial SMX concentration and contact time but decreased with increasing solution ionic strength.Kinetic data were best described by the pseudo second-order model.Equilibrium data were best represented by the Langmuir model,and the Freundlich constant (n) indicated a favorable adsorption process.The maximum adsorption capacity of SMX was 235.29 mg/g for CTMAB-Mt,155.28 mg/g for HDAPS-Mt and 242.72 mg/g for BHDAP-Mt.Thermodynamic parameters were calculated to evaluate the spontaneity and endothermic or exothermic nature.The adsorption mechanism was found to be dominated by electrostatic interaction,while hydrophobic interaction played a secondary role.

  12. Preparation of polystyrene–clay nanocomposite by solution intercalation technique

    Indian Academy of Sciences (India)

    P K Paul; S A Hussain; D Bhattacharjee; M Pal

    2013-06-01

    Polymer–clay nanocomposites of commercial polystyrene (PS) and clay laponite were prepared via solution intercalation technique. Laponite was modified suitably with the well known cationic surfactant cetyltrimethyl ammonium bromide by ion-exchange reaction to render laponite miscible with hydrophobic PS. X-ray diffraction analysis in combination with scanning electron microscopy gives an idea of structural and morphological information of PS–laponite nanocomposite for different varying organo-laponite contents. Intercalation of PS chain occurs into the interlayer spacings of laponite for low organo-laponite concentration in the PS–O-laponite mixture. However, aggregation and agglomeration occur at higher clay concentration. The molecular bond vibrational profile of laponite as well as PS–laponite nanocomposite have been explored by Fourier transform infrared spectroscopy. Thermogravimetric analysis along with differential scanning calorimetry results reveal the enhancement of both thermal stability and glass transition temperature of PS due to the incorporation of clay platelets.

  13. Magnetism in intercalated graphene

    Energy Technology Data Exchange (ETDEWEB)

    Ali, Sajid [Department of Electrical Engineering, Indian Institute of Technology Madras, Chennai – 600036 (India); Nanda, B. R. K. [Department of Physics, Indian Institute of Technology Madras, Chennai – 600036 (India)

    2016-05-23

    Using density functional calculations we explore the possibilities of inducing spin moments in otherwise non-magnetic electronic structure of graphene. Through intercalation of H, N, O and F atoms between two hexagonal stacked graphene layers, we show that unpaired electrons can be generated when the planar coordinates of the functional atoms coincide with the center of the graphene hexagon. The spin-half states are realized at the functional sites for certain values of interlayer separations. For oxygen and fluorine these interlayer separations represent the natural stable phases and for hydrogen and nitrogen they induce instability which can be overcome by applying external pressure. We attribute the formation of spin-half states to the one dimensional confinement potential exerted by the graphene layers on the valence electrons of the functional elements.

  14. Magnetism in intercalated graphene

    Science.gov (United States)

    Ali, Sajid; Nanda, B. R. K.

    2016-05-01

    Using density functional calculations we explore the possibilities of inducing spin moments in otherwise non-magnetic electronic structure of graphene. Through intercalation of H, N, O and F atoms between two hexagonal stacked graphene layers, we show that unpaired electrons can be generated when the planar coordinates of the functional atoms coincide with the center of the graphene hexagon. The spin-half states are realized at the functional sites for certain values of interlayer separations. For oxygen and fluorine these interlayer separations represent the natural stable phases and for hydrogen and nitrogen they induce instability which can be overcome by applying external pressure. We attribute the formation of spin-half states to the one dimensional confinement potential exerted by the graphene layers on the valence electrons of the functional elements.

  15. Synthesis of Various Polyaniline / Clay Nanocomposites Derived from Aniline and Substituted Aniline Derivatives by Mechanochemical Intercalation Method

    Directory of Open Access Journals (Sweden)

    N. Kalaivasan

    2010-01-01

    Full Text Available Polyaniline clay nanocomposite can be prepared by mechano-chemical method in which intercalation of anilinium ion into the clay lattices accomplished by mechanical grinding of sodium montmorillonite (Na+MMT in presence of anilinium hydrochloride at room temperature using mortar & pestle for about 30 min and subsequent grinding with oxidizing agent, ammonium peroxysulfate. The appearance of green colour indicates the formation of polyaniline/clay nanocomposite (PANI/Clay. Similarly aniline derivatives like o-toludine and o-anisidine in the form of HCl salt can form intercalation into the clay lattices. The intercalated aniline derivatives were ground mechanically in presence of oxidizing agent ammonium peroxysulfate lead to formation of substituted polyaniline/ clay nanocomposites. The characteristics of various polyaniline-clay nanocomposites were investigated using UV-Visible, FT-IR, cyclic voltammetry studies.

  16. Preparation of PAA/AM/MMT Hybrid by Intercalation Polymerization

    Institute of Scientific and Technical Information of China (English)

    WANG; YunPu

    2001-01-01

    Over the last few years, Montmorillonite (MMT) was widely used as a special inorganic material for preparing Polymer/MMT nanocompsites. MMT is a clay imineral consisting of stacked silicate sheets whose thickness is about 10A. Through intercalation a large number of polymer-clay nanocomposites have been prepared such as Nylon-clay hybrid [1], PS-clay hybrid [2], Poly (methyl methacrylate) (PMMA)-clay hybrid [3], etc.  In this article, the synthesis and properties of Poly (acrylic acid/acrylamide)/MMT hybrid (PAAAM/MMT) were studied. X-ray diffraction and Transmission electron microscopy were used to characterize the hybrid material. DSC has been used to study its property. Results showed that the intercalating reagents have entered the space of MMT's layers and enlarged them. At the same time, the MMT dispersed homogeneously in acrylic acid and acrylamide monomers that allow MMT to disperse in PAAAM matrix in the monolayer form.  ……

  17. Polymer-Dependent Layer Structures in Montmorillonite Nanocomposites

    Directory of Open Access Journals (Sweden)

    Justyna Strankowska

    2011-12-01

    Full Text Available We have studied structural differences among tetrahedral and octahedral sodium Montmorillonite layer arrangements in naturally occurring and synthetic montmorillonite clay minerals, as well as their poly(ethylene oxide and poly(ε-coprolatone polymer nanocomposites.

  18. Docking studies on DNA intercalators.

    Science.gov (United States)

    Gilad, Yocheved; Senderowitz, Hanoch

    2014-01-27

    DNA is an important target for the treatment of multiple pathologies, most notably cancer. In particular, DNA intercalators have often been used as anticancer drugs. However, despite their relevance to drug discovery, only a few systematic computational studies were performed on DNA-intercalator complexes. In this work we have analyzed ligand binding sites preferences in 63 high resolution DNA-intercalator complexes available in the PDB and found that ligands bind preferentially between G and C and between the C and A base pairs (70% and 11%, respectively). Next, we examined the ability of AUTODOCK to accurately dock ligands into preformed intercalation sites. Following the optimization of the docking protocol, AUTODOCK was able to generate conformations with RMSD values AUTODOCK was able to successfully distinguish between the intercalation site and the minor groove site. However, in all cases the crystal structures and poses tightly clustered around it had a lower score than the best scoring poses suggesting a potential scoring problem with AUTODOCK. A close examination of all cases where the top ranked pose had an RMSD value >2.00 Å suggests that AUTODOCK may overemphasize the hydrogen bonding term. A decision tree was built to identify ligands which are likely to be accurately docked based on their characteristics. This analysis revealed that AUTODOCK performs best for intercalators characterized by a large number of aromatic rings, low flexibility, high molecular weight, and a small number of hydrogen bond acceptors. Finally, for canonical B-DNA structures (where preformed sites are unavailable), we demonstrated that intercalation sites could be formed by inserting an anthracene moiety between the (anticipated) site-flanking base pairs and by relaxing the structure using either energy minimization or preferably molecular dynamics simulations. Such sites were suitable for the docking of different intercalators by AUTODOCK.

  19. Microstructure and mechanical properties of neoprene montmorillonite nanocomposites

    Science.gov (United States)

    Yeh, Meng-Heng; Hwang, Weng-Sing; Cheng, Lin-Ri

    2007-03-01

    To investigate the microstructure and mechanical properties of neoprene-montmorillonite nanocomposite, three modified montmorillonite are used. An X-ray diffractometer is used to measure the corresponding change in d-spacing. Scanning electron microscopy is employed to investigate the morphology of the various composites. Transmission electron microscopy is employed to investigate the composite of montmorillonite and neoprene. The results indicate that the addition of montmorillonite enhances the mechanical properties of neoprene significantly.

  20. Nanocomposites chitosan/montmorillonite for drug delivery system; Nanocompositos quitosana/montmorilonita para aplicacao em liberacao controlada de farmacos

    Energy Technology Data Exchange (ETDEWEB)

    Braga, Carla R. Costa; Barbosa, Rossemberg C. [Universidade Federal de Campina Grande (PPCEM/UFCG), PB (Brazil). Programa de Pos-graduacao em Ciencia e Engenharia de Materiais; Lima, Rosemary S. Cunha [Universidade Federal de Campina Grande (PPEP/UFCG), PB (Brazil). Programa de Pos-graduacao em Engenharia de Processos; Fook, Marcus V. Lia; Silva, Suedina M. Lima, E-mail: suedina@dema.ufcg.edu.b [Universidade Federal de Campina Grande (UAEMat/UFCG), PB (Brazil). Unidade Academica de Engenharia de Materiais

    2009-07-01

    In drugs delivery system the incorporation of an inorganic nanophase in polymer matrix, i.e. production of an inorganic-organic nanocomposite is an attractive alternative to obtain a constant release rate for a prolonged time. This study was performed to obtain films of nanocomposites Chitosan/montmorillonite intercalation by the technique of solution in the proportions of 1:1, 5:1 and 10:1. The nanocomposites were characterized by infrared spectroscopy, X-ray diffraction and thermogravimetric analysis. The results indicated that the feasibility of obtaining films of nanocomposites exfoliate. Among the suggested applications for films developed in this study includes them use for drugs delivery system. (author)

  1. Voltammetric characterization of montmorillonite-based organo derivatives

    OpenAIRE

    Navrátilová, Zuzana; Turčíková, Lenka; Plačková, Adriana

    2012-01-01

    Organo derivatives of clay mineral montmorillonite were prepared by modification of montmorillonite (type SAz-1) with three alkylammonium cations – hexadecyltrimethylammonium (HDTM), benzyldimethylhexadecylammonium (BDH), and hexadecylpyridinium bromide (HDP). The prepared organo-montmorillonites were characterized by X-Ray diffraction and infrared spectroscopy to test the alkylammonium cations presence in the organo derivatives. Multisweep cyclic voltammetry of copper at carbon paste e...

  2. Adsorption of the disinfectant benzalkonium chloride on montmorillonite. Synergistic effect in mixture of molecules with different chain lengths.

    Science.gov (United States)

    Zanini, Graciela P; Ovesen, Rikke Gleerup; Hansen, H C B; Strobel, Bjarne W

    2013-10-15

    The biocide benzalkonium chloride (BAC) is a mix of cationic alkylbenzyldimethylammonium surfactants having different alkyl chain lengths. A comparative study of adsorption on the phyllosilicate clay montmorillonite of two of these surfactants, with alkyl chains having respectively 12 C atoms (BAC-12) and 14 C atoms (BAC-14), and a mixture of both surfactants is presented in this work. Adsorption isotherms were performed for individual surfactants and for a 1:1 mixture BAC-12+BAC-14. The adsorption was investigated in an ample concentration range that covers almost seven orders of magnitude in concentrations (from 1 nM to 10 mM), range that includes environmentally relevant concentrations. Quantification of BAC was performed by HPLC-UV and LC-MS and the results were completed with powder X-Ray diffraction. The adsorption of both surfactants leads to adsorption isotherms with two well differentiated steps. The first step corresponds almost exclusively to a cation exchange process, and the binding constant is very similar for both surfactants. The second step of the isotherms is observed at higher concentrations and adsorption is mainly driven by lateral interactions between surfactant molecules. The binding constant of this step is larger for BAC-14 than for BAC-12. Adsorption from a BAC-12+BAC-14 mixture shows a synergistic behaviour, possibly due to a better packing arrangement in the interlayer. Calculations show that in natural systems silicate clays are major sorbents of BAC at low concentrations whereas binding to humic acid is predominant at high concentrations.

  3. Ni clay neoformation on montmorillonite surface.

    Science.gov (United States)

    Dähn, R; Scheidegger, A; Manceau, A; Schlegel, M; Baeyens, B; Bradbury, M H

    2001-03-01

    Polarized extended X-ray absorption fine structure spectroscopy (P-EXAFS) was used to study the sorption mechanism of Ni on the aluminous hydrous silicate montmorillonite at high ionic strength (0.3 M NaClO4), pH 8 and a Ni concentration of 0.66 mM. Highly textured self-supporting clay films were obtained by slowly filtrating a clay suspension after a reaction time of 14 days. P-EXAFS results indicate that sorbed Ni has a Ni clay-like structural environment with the same crystallographic orientation as montmorillonite layers.

  4. 蒙脱土有机化改性的研究进展%Recent Progress in Organic Modification of Montmorillonite

    Institute of Scientific and Technical Information of China (English)

    邓朝霞

    2012-01-01

    Montmorillonite has wide application because of its special structure and having the dispersibility, dilatability and cation exchange. But montmorillonite is poor dispersion in the organic phase for its hydrophilic oleophobic property, so montmorillonite used in organic system must be disposed with the organic modification. The choice of organic modifier is the key to the process of montmorillonite organic modification. The research progress of modifying agent such as long chain alkyl quaternary ammonium salt, anionic surfactant, nonionic surfactant, coupling agent and organic amine and organic acids in organic modification of montmorillonite was summarized, which will have important significance to further montmorillonite resources development and application.%蒙脱土的结构特殊,具有可分散性、膨胀性和阳离子交换性等,应用广泛.但蒙脱土具有的亲水疏油性不利于其在有机相中分散,因此当蒙脱土应用于有机体系时必须对其进行有机化改性.有机改性剂的选择是蒙脱土有机化过程的关键.针对长链烷基季铵盐、阴离子表面活性剂、非离子表面活性剂、偶联剂以及有机胺和有机酸等改性剂在蒙脱土有机化改性方面的研究进展进行了综述,对于进一步深化蒙脱土资源的开发与应用将具有重要的意义.

  5. Adsorption of ferrous ions onto montmorillonites

    Energy Technology Data Exchange (ETDEWEB)

    Qin, Dawei, E-mail: qdw109@163.com [Qilu University of Technology, Jinan, 250353, Shandong (China); Niu, Xia [Qilu University of Technology, Jinan, 250353, Shandong (China); Qiao, Min; Liu, Gang; Li, Hongxin; Meng, Zhenxiao [Shandong SiBang pharmaceutical co., LTD, Jinan, Shandong, 250200 (China)

    2015-04-01

    Highlights: • Adsorption study of ferrous ions on montmorillonites. • Using ascorbic acid as antioxidants in adsorption process. • Fe (II)-MMT had good affinity for phosphate. - Abstract: The adsorption of Fe (II) onto montmorillonites was investigated through initial concentration, contact time, pH and temperature. During the whole adsorption process, the ascorbic acid (Vitamin C) was added as a kind of antioxidant, at the same time, deionized water (after boiling) and nitrogen protection were also used to avoid oxidation. The Fe{sup 2+}/Fe{sub total} ratio of the iron exists in the Fe-montmorillonites was found more than 95%. Two kinetic models, including pseudo-first-order and pseudo-second-order model, were used to analyze the adsorption process of Fe (II) on montmorillonites. The results of our study showed that adsorption process fitted with pseudo-second-order well. Adsorption isotherms showed that Langmuir model was better than Freundlich model. The thermodynamic parameters ΔG{sup 0} and ΔH{sup 0} were 3.696 kJ/mol and 6.689 kJ/mol (we just gave the values at 298 K), respectively. The positive values at different temperatures showed that the adsorption process was non-spontaneous and endothermic. The characteristics of materials were determined by X-ray diffraction (XRD), Fourier transform infrared (FT-IR), Surface area and porosity analyzer, Thermogravimetric analysis (TGA), Differential scanning calorimeter (DSC) and Zeta potential distribution.

  6. PREPARATION AND CHARACTERIZATION OF SOY PROTEIN ISOLATE (SPI)/MONTMORILLONITE (MMT) BIONANOCOMPOSITES

    Institute of Scientific and Technical Information of China (English)

    Lixue Xiang; Chang-yu Tang; Jing Can; Chao-yu Wang; Ke Wang; Qin Zhang; Qiang Fu; Shu-gao Zhao

    2009-01-01

    The bionanocomposites of soy protein isolate (SPI)/montmorillonite (MMT) have been prepared successfully via simple melt mixing, in which MMT was used as nanofiller and glycerol was used as plasticizer. Their structures and properties were characterized with X-ray diffraction (XRD), differential scanning calorimetry (DSC), scanning electron microscopy (SEM), thermogravimetric analysis and tensile testing. XRD, TEM and SEM results indicated that the MMT layers could be easily intercalated by the SPI matrix even by simple melt processing. The exfoliated MMT layers were randomly dispersed in the protein matrix as MMT content was low (less than 5 wt%), an incomplete exfoliation was evident from SEM results, and some primary particles were observed as the MMT content was high (from 5 wt% to 9 wt%). A significant improvement of the mechanical strength and thermal stability of SPI/MMT nanocomposites has been achieved. Our work suggests that simple melt processing is an efficient way to prepare SPI/MMT nanocomposites with exfoliated structure.

  7. Preparation and Characterization of Polymer-Grafted Montmorillonite-Lignocellulose Nanocomposites by In Situ Intercalative Polymerization

    Directory of Open Access Journals (Sweden)

    Tavengwa Bunhu

    2016-01-01

    Full Text Available Lignocellulose-clay nanocomposites were synthesized using an in situ intercalative polymerization method at 60°C and a pressure of 1 atm. The ratio of the montmorillonite clay to the lignocellulose ranged from 1 : 9 to 1 : 1 (MMT clay to lignocelluloses, wt%. The adsorbent materials were characterized by Fourier transform infrared spectroscopy (FTIR, thermogravimetric analysis (TGA, transmission electron microscopy (TEM, and X-ray powder diffraction (XRD. FTIR results showed that the polymers were covalently attached to the nanoclay and the lignocellulose in the nanocomposites. Both TEM and XRD analysis showed that the morphology of the materials ranged from phase-separated to intercalated nanocomposite adsorbents. Improved thermal stability, attributable to the presence of nanoclay, was observed for all the nanocomposites. The nanocomposite materials prepared can potentially be used as adsorbents for the removal of pollutants in water treatment and purification.

  8. Thermal Decomposition Kinetics of High Impact Polystyrene/ Organo Fe-montmorillonite Nanocomposites

    Institute of Scientific and Technical Information of China (English)

    刘宏; 孔庆红; 程宇和; 曹功源

    2012-01-01

    In this article, high impact polystyrene/organo Fe-montmorillonite (HIPS/Fe-OMT) nanocomposites were prepared by melting intercalation. The thermal stability of HIPS/Fe-OMT nanocomposites increased significantly compared to that of HIPS examined in thermal degradation conditions. Kinetic evaluations were performed by Kissinger, Flynn-Wall-Ozawa, Friedman methods and multivariate nonlinear regression. Apparent kinetic parameters for the overall degradation were determined. The resuRs showed that the activation energy of HIPS/Fe-OMT nanocomposites was higher than that of HIPS. A very good agreement between experimental and simulated curves was observed in dynamic conditions. Their decomposition reaction model was a single-step process of an nth-order reaction

  9. Stabilization of a hydrophobic natural dye by intercalation into organo-montmorillonite

    OpenAIRE

    2011-01-01

    NOTICE: this is the author’s version of a work that was accepted for publication in Applied Clay Science. Changes resulting from the publishing process, such as peer review, editing, corrections, structural formatting, and other quality control mechanisms may not be reflected in this document.Changes may have been made to this work since it was submitted for publication. A definitive version was subsequently published in Applied Clay Science, VOL54, ISSUE3-4, 28 September 2011. DOI10.1016/j.c...

  10. Characterized and cleaning process of montmorillonite clay from Parelhas, Rio Grande do Norte state, Brazil; Caracterizacao e processo de purificacao de argila montmorilonitica da cidade de Parelhas, RN, Brasil

    Energy Technology Data Exchange (ETDEWEB)

    Melo, G.N; Costa, T.C.C; Paskocimas, C.A, E-mail: gudson.nicolau@gmail.co [Universidade Federal do Rio Grande do Norte (UFRN), Natal, RN (Brazil)

    2010-07-01

    The application of montmorillonite nano composites has been improved in order to obtain dispersed phase with particles of nano metric dimensions. To obtain these nanoparticles, the clays must pass an effective purification process for removing unwanted materials, which would undermine the processes of intercalation and exfoliation of montmorillonite in a polymer matrix. This study intention to characterize and purify a montmorillonite clay from deposit recently discovered in the city of Parelhas in Rio Grande do Norte, through the separation of coarser materials by decantation followed by a chemical attack that promoted oxidation in samples where it was realized reduction of impurities such as organic matter and other substances that would hinder the achievement of nanoparticles. Under these conditions, the clay is suitable for the work as dispersed phase in a polymer matrix nano composite. The results were demonstrated by analysis of scanning electron microscopy (SEM), chemical analysis, BET and X-ray diffraction (XRD). (author)

  11. Residual Monomer Content and Its Release into Water from the Denture Base Nanocomposite Using Organic Montmorillonite as Reinforcement

    Institute of Scientific and Technical Information of China (English)

    LI Hongbo; ZHANG Chao; LI Zhian; WANG Yining; XIAO Qun

    2008-01-01

    A novel kind of denture base nanocomposite was prepared by polymethyl methyacrylate(PMMA) and cethyltrimethylammonium bromide modified organic montmorillonite (OMMT).The dispersion of montmorillonite in the polymer matrix was characterized by x-ray diffraction (XRD) and transimission electron microscope (TEM).The content of residual MMA in nanocomposites and the amount of MMA released to water from nanocomposites were determined by gas chromatography (GC).The analysis of TEM and XRD showed that exfoliated-intercalated and intercalated nanocomposites were formed when the content of OMMT was 3% and 5% in the PMMA powder respectively.The results of GC showed that the residual MMA increased with the increase of OMMT content in the polymer matrix.After 7 days in water,the amount of MMA released into water from the nanocomposites tended to be stable.The results of one-way ANOVA and t-test showed that OMMT gave a significant increase of residual MMA concentration (p<0.05) in nanocomposites.

  12. Investigation of microstructures and ultraviolet aging properties of organo-montmorillonite/SBS modified bitumen

    Energy Technology Data Exchange (ETDEWEB)

    Zhang Henglong [Key Laboratory of Silicate Materials Science and Engineering of Ministry of Education, Wuhan University of Technology, Wuhan (China); Yu Jianying, E-mail: jyyu@whut.edu.cn [Key Laboratory of Silicate Materials Science and Engineering of Ministry of Education, Wuhan University of Technology, Wuhan (China); Wang Huacai; Xue Lihui [Center for Materials Research and Analysis, Wuhan University of Technology, Wuhan 430070 (China)

    2011-10-03

    Highlights: {yields} Microstructures and ultraviolet (UV) aging properties of organo-montmorillonite (OMMT)/Styrene-butadiene-styrene(SBS) modified bitumen were investigated by X-ray diffraction, Fourier transform infrared spectroscopy, atomic force microscopy and physical properties tests. {yields} OMMT/SBS modified bitumen forms an intercalated structure. {yields} The phase contrast between the dispersed domains and the matrix is inverted in SBS modified bitumen, which is decreased with the introduction of OMMT. {yields} The UV aging resistance of SBS modified bitumen can be improved obviously with the addition of OMMT. - Abstract: Organo-montmorillonite(OMMT)/Styrene-butadiene-styrene(SBS) modified bitumen nanocomposites were prepared by melt blending. The microstructures of OMMT/SBS modified bitumen were characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR) and atomic force microscopy (AFM), respectively. The effect of OMMT on ultraviolet (UV) aging properties of SBS modified bitumen was investigated. FTIR and XRD analyses indicate that the OMMT/SBS modified bitumen forms an intercalated structure. It is observed that the phase contrast between the dispersed domains and the matrix is inverted in SBS modified bitumen, which is decreased with the introduction of OMMT according to AFM analysis. As a result of UV aging, both viscosity aging index and softening point increment of OMMT/SBS modified bitumen decrease significantly. There is a single phase trend in the morphology of the bitumen after aging, which is accelerated by the existence of SBS. However, these changes can be effectively prevented under the influence of OMMT, indicating the good UV aging resistance of OMMT/SBS modified bitumen.

  13. 聚氨酯/蒙脱土纳米复合材料%Polyurethane/Montmorillonite Nanocomposites

    Institute of Scientific and Technical Information of China (English)

    黄文勇; 庞浩; 赵树录; 张先文; 廖兵

    2002-01-01

      In recent years, layered silicates/polyurethane nanocomposites have attracted a great deal of attention because of the improvements in the mechanical, thermal and gas barrier properties of the polymer. These improvements are brought about by having a small amount of layered silicates dispersed at the nanometer scale. Polyurethane intercalation into layered silicates is a novel approach to synthesize organic-inorganic Polyurethane nanocomposites. The recent research and development of polyurethane/montmorillonite(PU/MMT)nanocomposites material were reviewed, including the new features of PU/MMT nanocomposites, as well as organo-modification of montmorillonite, the structure, preparation and characterization of PU/MMT nanocomposites.%  蒙脱土的插层复合是聚氨酯改性的新方法。本文介绍了当前有关聚氨酯/蒙脱土(PU/MMT)纳米复合材料的研究进展,包括PU/MMT的新特性、蒙脱土的有机改性、PU/MMT纳米复合材料的制备方法与结构及性能的表征,并对这种复合材料的研发前景进行了展望。

  14. Superconductivity in graphite intercalation compounds

    Energy Technology Data Exchange (ETDEWEB)

    Smith, Robert P. [Cavendish Laboratory, University of Cambridge, Madingley Road, Cambridge CB3 0HE (United Kingdom); Weller, Thomas E.; Howard, Christopher A. [Department of Physics & Astronomy, University College of London, Gower Street, London WCIE 6BT (United Kingdom); Dean, Mark P.M. [Department of Condensed Matter Physics and Materials Science, Brookhaven National Laboratory, Upton, NY 11973 (United States); Rahnejat, Kaveh C. [Department of Physics & Astronomy, University College of London, Gower Street, London WCIE 6BT (United Kingdom); Saxena, Siddharth S. [Cavendish Laboratory, University of Cambridge, Madingley Road, Cambridge CB3 0HE (United Kingdom); Ellerby, Mark, E-mail: mark.ellerby@ucl.ac.uk [Department of Physics & Astronomy, University College of London, Gower Street, London WCIE 6BT (United Kingdom)

    2015-07-15

    Highlights: • Historical background of graphite intercalates. • Superconductivity in graphite intercalates and its place in the field of superconductivity. • Recent developments. • Relevant modeling of superconductivity in graphite intercalates. • Interpretations that pertain and questions that remain. - Abstract: The field of superconductivity in the class of materials known as graphite intercalation compounds has a history dating back to the 1960s (Dresselhaus and Dresselhaus, 1981; Enoki et al., 2003). This paper recontextualizes the field in light of the discovery of superconductivity in CaC{sub 6} and YbC{sub 6} in 2005. In what follows, we outline the crystal structure and electronic structure of these and related compounds. We go on to experiments addressing the superconducting energy gap, lattice dynamics, pressure dependence, and how these relate to theoretical studies. The bulk of the evidence strongly supports a BCS superconducting state. However, important questions remain regarding which electronic states and phonon modes are most important for superconductivity, and whether current theoretical techniques can fully describe the dependence of the superconducting transition temperature on pressure and chemical composition.

  15. Montmorillonite Dissolution in Simulated Lung Fluids

    Science.gov (United States)

    Schmidt, M.; Wendlandt, R. F.

    2008-12-01

    Because lung fluids" first interaction is with the surface of inhaled grains, the surface properties of inhaled mineral dusts may have a generally mitigating effect on cytotoxicity and carcinogenicity. Wendlandt et al. (Appl. Geochem. 22, 2007) investigated the surface properties of respirable-sized quartz grains in bentonites and recognized pervasive montmorillonite surface coatings on silica grains. The purpose of this study was to determine the dissolution rate and biodurability of montmorillonite in simulated lung fluids and to assess its potential to mitigate silica cytotoxicity. Modified batch reaction experiments were conducted on purified and size fractionated calcic (SAz-2; 0.4-5 μm) and sodic (DC-2; 0.4-2 μm) montmorillonites for 120 to 160 days of reaction time at 37°C in both simulated extracellular lung fluid (Lu) and simulated lysosomal fluid (Ly). Modified batch experiments simulated a flow-through setup and minimized sample handling difficulties. Reacted Lu and Ly fluid was analyzed for Mg, Al, and Si on an ICP-OE spectrometer. Steady state dissolution was reached 90-100 days after the start of the experiment and maintained for 40-60 days. Measured montmorillonite dissolution rates based on BET surface areas and Si steady state release range from 4.1x10-15 mol/m2/s at the slowest to 1.0x10-14 mol/m2/s at the fastest with relative uncertainties of less than 10%. Samples reacting in Ly (pH = 4.55) dissolved faster than those in Lu (pH = 7.40), and DC-2 dissolved faster than SAz-2. The measured range of biodurabilities was 1,300 to 3,400 years for a 1 μm grain assuming a spherical volume and a molar volume equal to that of illite. The difference in salinities of the two fluids was too slight to draw conclusions about the relationship of ionic strength to dissolution rate. Results indicate that montmorillonite dissolution is incongruent and edge controlled. Dissolution rates for DC- 2 and SAz-2 clays were comparable to those reported in the

  16. Montmorillonite, oligonucleotides, RNA and origin of life

    Science.gov (United States)

    Ertem, Gozen

    2004-01-01

    Na-montmorillonite prepared from Volclay by the titration method facilitates the self-condensation of ImpA, the 5'-phosphorimidazolide derivative of adenosine. As was shown by AE-HPLC analysis and selective enzymatic hydrolysis of products, oligo(A)s formed in this reaction are 10 monomer units long and contain 67% 3',5'-phosphodiester bonds (Ferris and Ertem, 1992a). Under the same reaction conditions, 5'-phosphorimidazolide derivatives of cytidine, uridine and guanosine also undergo self-condensation producing oligomers containing up to 12-14 monomer units for oligo(C)s to 6 monomer units for oligo(G)s. In oligo(C)s and oligo(U)s, 75-80% of the monomers are linked by 2',5'-phosphodiester bonds. Hexamer and higher oligomers isolated from synthetic oligo(C)s formed by montmorillonite catalysis, which contain both 3',5'- and 2',5'-linkages, serve as catalysts for the non-enzymatic template directed synthesis of oligo(G)s from activated monomer 2-MeImpG, guanosine 5'-phospho-2-methylimidazolide (Ertem and Ferris, 1996). Pentamer and higher oligomers containing exclusively 2',5'-linkages, which were isolated from the synthetic oligo(C)s, also serve as templates and produce oligo(G)s with both 2',5'- and 3',5'-phosphodiester bonds. Kinetic studies on montmorillonite catalyzed elongation rates of oligomers using the computer program SIMFIT demonstrated that the rate constants for the formation of oligo(A)s increased in the order of 2-mer < 3-mer < 4-mer ... < 7-mer (Kawamura and Ferris, 1994). A decameric primer, dA(pdA)8pA bound to montmorillonite was elongated to contain up to 50 monomer units by daily addition of activated monomer ImpA to the reaction mixture (Ferris, Hill and Orgel, 1996). Analysis of dimer fractions formed in the montmorillonite catalyzed reaction of binary and quaternary mixtures of ImpA, ImpC, 2-MeImpG and ImpU suggested that only a limited number of oligomers could have formed on the primitive Earth rather than equal amounts of all possible

  17. Preservation of glutamic acid-iron chelate into montmorillonite to efficiently degrade Reactive Blue 19 in a Fenton system under sunlight irradiation at neutral pH

    Science.gov (United States)

    Huang, Zhujian; Wu, Pingxiao; Gong, Beini; Yang, Shanshan; Li, Hailing; Zhu, Ziao; Cui, Lihua

    2016-05-01

    To further enhance the visible light responsive property and the chemical stability of Fe/clay mineral catalysts, glutamic acid-iron chelate intercalated montmorillonite (G-Fe-Mt) was developed. The physiochemical properties of G-Fe-Mt were investigated by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), UV-vis diffuse reflectance spectroscopy (DRS), etc. The results showed that glutamic acid-iron chelates were successfully intercalated into the gallery of montmorillonite and the intercalated glutamic acid-iron chelate molecules were well preserved. The product G-Fe-Mt displayed excellent catalytic performance in heterogeneous photo-Fenton reaction under sunlight irradiation at acidic and neutral pH values. The chelation and the visible light responsiveness of glutamic acid produce a synergistic effect leading to greatly enhanced sunlight-Fenton reaction catalyzed by the heterogeneous G-Fe-Mt under neutral pH. G-Fe-Mt is a promising catalyst for advanced oxidation processes.

  18. Ice nucleation of ammonia gas exposed montmorillonite mineral dust particles

    Directory of Open Access Journals (Sweden)

    A. Salam

    2007-01-01

    Full Text Available The ice nucleation characteristics of montmorillonite mineral dust aerosols with and without exposure to ammonia gas were measured at different atmospheric temperatures and relative humidities with a continuous flow diffusion chamber. The montmorillonite particles were exposed to pure (100% and diluted ammonia gas (25 ppm at room temperature in a stainless steel chamber. There was no significant change in the mineral dust particle size distribution due to the ammonia gas exposure. 100% pure ammonia gas exposure enhanced the ice nucleating fraction of montmorillonite mineral dust particles 3 to 8 times at 90% relative humidity with respect to water (RHw and 5 to 8 times at 100% RHw for 120 min exposure time within our experimental conditions. The percentages of active ice nuclei were 2 to 9 times higher at 90% RHw and 2 to 13 times higher at 100% RHw in 25 ppm ammonia exposed montmorillonite compared to unexposed montmorillonite. All montmorillonite particles are more efficient as ice nuclei with increasing relative humidities and decreasing temperatures. The activation temperature of montmorillonite exposed to 100% pure ammonia was 12°C higher than for unexposed montmorillonite particles at 90% RHw and 10°C higher at 100% RHw. In the 25 ppm ammonia exposed montmorillonite experiments, the activation temperature was 7°C warmer than unexposed montmorillonite at 100% RHw. Degassing does not reverse the ice nucleating ability of ammonia exposed montmorillonite mineral dust particles. This is the first experimental evidence that ammonia gas exposed montmorillonite mineral dust particles can enhance its activation as ice nuclei and that the activation can occur at temperatures warmer than –10°C where natural atmospheric ice nuclei are very scarce.

  19. Investigation of the Structural Variation after the Intercalation of Cetylpyridinium Chloride into V2O5 Xerogel

    Directory of Open Access Journals (Sweden)

    Elidia Maria Guerra

    2014-08-01

    Full Text Available A new hybrid material using vanadium pentoxide xerogel in different concentration of the cationic surfactant cetylpyridinium chloride (V2O5CPC is investigated. The insertion was accompanied by XRD, FTIR and SEM characterization. These studies revealed the presence of a lamellar structure for the V2O5CPC hybrid material in all concentrations of cetylpyridinium chloride. The intercalation reaction was evidenced on basis of the increase in the d-spacing as well as the displacement of the infrared bands toward lower energy levels. The CPC intercalation occurred by reorganize intermittently forming two domains within the matrix.

  20. The mechanism of caesium intercalation of graphene.

    Science.gov (United States)

    Petrović, M; Šrut Rakić, I; Runte, S; Busse, C; Sadowski, J T; Lazić, P; Pletikosić, I; Pan, Z-H; Milun, M; Pervan, P; Atodiresei, N; Brako, R; Šokčević, D; Valla, T; Michely, T; Kralj, M

    2013-01-01

    Properties of many layered materials, including copper- and iron-based superconductors, topological insulators, graphite and epitaxial graphene, can be manipulated by the inclusion of different atomic and molecular species between the layers via a process known as intercalation. For example, intercalation in graphite can lead to superconductivity and is crucial in the working cycle of modern batteries and supercapacitors. Intercalation involves complex diffusion processes along and across the layers; however, the microscopic mechanisms and dynamics of these processes are not well understood. Here we report on a novel mechanism for intercalation and entrapment of alkali atoms under epitaxial graphene. We find that the intercalation is adjusted by the van der Waals interaction, with the dynamics governed by defects anchored to graphene wrinkles. Our findings are relevant for the future design and application of graphene-based nano-structures. Similar mechanisms can also have a role for intercalation of layered materials.

  1. Detection of polyaromatic hydrocarbons using DNA intercalation

    Energy Technology Data Exchange (ETDEWEB)

    Weetall, H.H.; Pandey, P.; Horuath, J. [National Institute of Standards and Technology, Gaithersburg, MD (United States)

    1995-12-01

    Polyaromatic hydrocarbons (PAH`S) have be monitored using intercalation of double stranded DNA. Three approaches have been examined. The first, an electrochemical method uses an electroactive intercalating agent. When intercalated into DNA it cannot transfer electrons to an electrode. When displaced by a PAH, it can be detected electrochemically. The second method utilizes fluorescence polarization. A fluorescent intercalating agent, when intercalated into DNA will show increased polarization. When displaced by a competing PAH, a decrease in polarization is observed. The third technique involves evanescent wave technology. Double stranded DNA in close proximity to the wave guide will show a decreased fluorescence when a fluorescent intercalator is displaced by a PAH. Each of these techniques will be described and examples of results presented.

  2. Intercalating nucleic acids: the influence of linker length and intercalator type on their duplex stabilities.

    Science.gov (United States)

    Christensen, Ulf B; Wamberg, Michael; El-Essawy, Farag A G; Ismail, Abd El-Hamid; Nielsen, Christina B; Filichev, Vyacheslav V; Jessen, Carsten H; Petersen, Michael; Pedersen, Erik B

    2004-01-01

    Six new examples of intercalating nucleic acids were synthesized in order to evaluate the dependence of the length of the linker between oligo and intercalator on the thermal stability of their corresponding duplexes and triplexes.

  3. Adsorption of mixed cationic-nonionic surfactant and its effect on bentonite structure.

    Science.gov (United States)

    Zhang, Yaxin; Zhao, Yan; Zhu, Yong; Wu, Huayong; Wang, Hongtao; Lu, Wenjing

    2012-01-01

    The adsorption of cationic-nonionic mixed surfactant onto bentonite and its effect on bentonite structure were investigated. The objective was to improve the understanding of surfactant behavior on clay mineral for its possible use in remediation technologies of soil and groundwater contaminated by toxic organic compounds. The cationic surfactant used was hexadecylpyridinium bromide (HDPB), and the nonionic surfactant was Triton X-100 (TX100). Adsorption of TX100 was enhanced significantly by the addition of HDPB, but this enhancement decreased with an increase in the fraction of the cationic surfactant. Part of HDPB was replaced by TX100 which decreased the adsorption of HDPB. However, the total adsorbed amount of the mixed surfactant was still increased substantially, indicating the synergistic effect between the cationic and nonionic surfactants. The surfactant-modified bentonite was characterized by Brunauer-Emmett-Teller specific surface area measurement, Fourier transform infrared spectroscopy, and thermogravimetric-derivative thermogravimetric/differential thermal analyses. Surfactant intercalation was found to decrease the bentonite specific surface area, pore volume, and surface roughness and irregularities, as calculated by nitrogen adsorption-desorption isotherms. The co-adsorption of the cationic and nonionic surfactants increased the ordering conformation of the adsorbed surfactants on bentonite, but decreased the thermal stability of the organobentonite system.

  4. Preparation and Characterization of Organophilic Montmorillonite (12-maghnite Using Algerian Clay

    Directory of Open Access Journals (Sweden)

    Djamal Eddine Kherroub

    2014-12-01

    Full Text Available The aim of this work is to obtain an organophilic montmorillonite with Algerian modified clay (termed 12-maghnite. The organic surfactant used in this preparation is 12-aminolauric acid. The functionalization of the organophilic clay was confirmed by infrared spectroscopy (IR. The obtained organoclay was characterized by X-ray diffraction (XRD which shows a remarkable increase of the basal distance that reaches up to 17.62 Å. The transmission electron microscopy analysis (TEM supports fully the result obtained by XRD analysis. The novelty of this work is the exploitation of local clay that is widely available, inexpensive and has excellent properties and high quality features, which make it the subject of continuing research. These results will be a starting point and an essential reference for a comparative study, with the results of future works concerning the synthesis of Polymer/12-Maghnite nanocomposites.

  5. Rigid palm oil-based polyurethane foam reinforced with diamine-modified montmorillonite nanoclay

    Science.gov (United States)

    Haziq Dzulkifli, Mohd; Yazid Yahya, Mohd; Majid, Rohah A.

    2017-05-01

    This paper presents work on organically-modified montmorillonite (MMT) nanoclay embedded in rigid palm oil-based polyurethane (PU) foam. MMT was modified with organic surfactant diamino propane (DAP). PU foam was fabricated in closed mold, and the amount of DAP-MMT was varied in each foam formulation. The obtained foam was tested for its microstructure and morphology. Appearance of peaks from infra-red spectra corresponding to N-H, C=O, and C-N confirms the formation of PU networks. Scanning electron microscopy (SEM) revealed fine, closed-cellular structure at low clay loading; increasing DAP-MMT content induced larger cell sizes with blowholes. X-ray diffraction (XRD) indicates fully-exfoliated clays at 1 wt. % and partial-exfoliation at 3 wt. % clay loading, suggesting clumping of clays as DAP-MMT content increased.

  6. Dynamics of DNA/intercalator complexes

    Science.gov (United States)

    Schurr, J. M.; Wu, Pengguang; Fujimoto, Bryant S.

    1990-05-01

    Complexes of linear and supercoiled DNAs with different intercalating dyes are studied by time-resolved fluorescence polarization anisotropy using intercalated ethidium as the probe. Existing theory is generalized to take account of excitation transfer between intercalated ethidiums, and Forster theory is shown to be valid in this context. The effects of intercalated ethidium, 9-aminoacridine, and proflavine on the torsional rigidity of linear and supercoiled DNAs are studied up to rather high binding ratios. Evidence is presented that metastable secondary structure persists in dye-relaxed supercoiled DNAs, which contradicts the standard model of supercoiled DNAs.

  7. In situ study of CO₂ and H₂O partitioning between Na-montmorillonite and variably wet supercritical carbon dioxide.

    Science.gov (United States)

    Loring, John S; Ilton, Eugene S; Chen, Jeffrey; Thompson, Christopher J; Martin, Paul F; Bénézeth, Pascale; Rosso, Kevin M; Felmy, Andrew R; Schaef, Herbert T

    2014-06-03

    Shale formations play fundamental roles in large-scale geologic carbon sequestration (GCS) aimed primarily to mitigate climate change and in smaller-scale GCS targeted mainly for CO2-enhanced gas recovery operations. Reactive components of shales include expandable clays, such as montmorillonites and mixed-layer illite/smectite clays. In this study, in situ X-ray diffraction (XRD) and in situ infrared (IR) spectroscopy were used to investigate the swelling/shrinkage and H2O/CO2 sorption of Na(+)-exchanged montmorillonite, Na-SWy-2, as the clay is exposed to variably hydrated supercritical CO2 (scCO2) at 50 °C and 90 bar. Measured d001 values increased in stepwise fashion and sorbed H2O concentrations increased continuously with increasing percent H2O saturation in scCO2, closely following previously reported values measured in air at ambient pressure over a range of relative humidities. IR spectra show H2O and CO2 intercalation, and variations in peak shapes and positions suggest multiple sorbed types of H2O and CO2 with distinct chemical environments. Based on the absorbance of the asymmetric CO stretching band of the CO2 associated with the Na-SWy-2, the sorbed CO2 concentration increases dramatically at sorbed H2O concentrations from 0 to 4 mmol/g. Sorbed CO2 then sharply decreases as sorbed H2O increases from 4 to 10 mmol/g. With even higher sorbed H2O concentrations as saturation of H2O in scCO2 was approached, the concentration of sorbed CO2 decreased asymptotically. Two models, one involving space filling and the other a heterogeneous distribution of integral hydration states, are discussed as possible mechanisms for H2O and CO2 intercalations in montmorillonite. The swelling/shrinkage of montmorillonite could affect solid volume, porosity, and permeability of shales. Consequently, the results may aid predictions of shale caprock integrity in large-scale GCS as well as methane transmissivity in enhanced gas recovery operations.

  8. Thermally cleavable surfactants

    Science.gov (United States)

    McElhanon, James R.; Simmons, Blake A.; Zifer, Thomas; Jamison, Gregory M.; Loy, Douglas A.; Rahimian, Kamyar; Long, Timothy M.; Wheeler, David R.; Staiger, Chad L.

    2006-04-04

    Two new surfactant molecules are reported which contain thermally labile Diels-Alder adducts connecting the polar and non-polar sections of each molecule. The two surfactants possess identical non-polar dodecyl tail segments but exhibit different polar headgroups. The surfactants become soluble in water when anionic salts are formed through the deprotonation of the surfactant headgroups by the addition of potassium hydroxide. When either surfactant is exposed to temperature above about 60.degree. C., the retro Diels-Alder reaction occurs, yielding hydrophilic and hydrophobic fragments and the aqueous solutions of the surfactants subsequently exhibit loss of all surface-active behavior.

  9. Thermally cleavable surfactants

    Energy Technology Data Exchange (ETDEWEB)

    McElhanon, James R. (Manteca, CA); Simmons, Blake A. (San Francisco, CA); Zifer, Thomas (Manteca, CA); Jamison, Gregory M. (Albuquerque, NM); Loy, Douglas A. (Albuquerque, NM); Rahimian, Kamyar (Albuquerque, NM); Long, Timothy M. (Urbana, IL); Wheeler, David R. (Albuquerque, NM); Staiger, Chad L. (Albuquerque, NM)

    2009-09-29

    Two new surfactant molecules are reported which contain thermally labile Diels-Alder adducts connecting the polar and non-polar sections of each molecule. The two surfactants possess identical non-polar dodecyl tail segments but exhibit different polar headgroups. The surfactants become soluble in water when anionic salts are formed through the deprotonation of the surfactant headgroups by the addition of potassium hydroxide. When either surfactant is exposed to temperature above about 60.degree. C., the retro Diels-Alder reaction occurs, yielding hydrophilic and hydrophobic fragments or the aqueous solutions of the surfactants subsequently exhibit loss of all surface-active behavior.

  10. Thermally cleavable surfactants

    Energy Technology Data Exchange (ETDEWEB)

    McElhanon, James R. (Manteca, CA); Simmons, Blake A. (San Francisco, CA); Zifer, Thomas (Manteca, CA); Jamison, Gregory M. (Albuquerque, NM); Loy, Douglas A. (Albuquerque, NM); Rahimian, Kamyar (Albuquerque, NM); Long, Timothy M. (Urbana, IL); Wheeler, David R. (Albuquerque, NM); Staiger, Chad L. (Albuquerque, NM)

    2009-11-24

    Two new surfactant molecules are reported which contain thermally labile Diels-Alder adducts connecting the polar and non-polar sections of each molecule. The two surfactants possess identical non-polar dodecyl tail segments but exhibit different polar headgroups. The surfactants become soluble in water when anionic salts are formed through the deprotonation of the surfactant headgroups by the addition of potassium hydroxide. When either surfactant is exposed to temperature above about 60.degree. C., the retro Diels-Alder reaction occurs, yielding hydrophilic and hydrophobic fragments or the aqueous solutions of the surfactants subsequently exhibit loss of all surface-active behavior.

  11. Prebiotic RNA Synthesis by Montmorillonite Catalysis

    Science.gov (United States)

    Jheeta, Sohan; Joshi, Prakash C.

    2014-08-01

    This review summarizes our recent findings on the role of mineral salts in prebiotic RNA synthesis, which is catalyzed by montmorillonite clay minerals. The clay minerals not only catalyze the synthesis of RNA but also facilitate homochiral selection. Preliminary data of these findings have been presented at the "Horizontal Gene Transfer and the Last Universal Common Ancestor (LUCA)" conference at the Open University, Milton Keynes, UK, 5-6 September 2013. The objective of this meeting was to recognize the significance of RNA in LUCA. We believe that the prebiotic RNA synthesis from its monomers must have been a simple process. As a first step, it may have required activation of the 5'-end of the mononucleotide with a leaving group, e.g., imidazole in our model reaction (Figure 1). Wide ranges of activating groups are produced from HCN under plausible prebiotic Earth conditions. The final step is clay mineral catalysis in the presence of mineral salts to facilitate selective production of functional RNA. Both the clay minerals and mineral salts would have been abundant on early Earth. We have demonstrated that while montmorillonite (pH 7) produced only dimers from its monomers in water, addition of sodium chloride (1 M) enhanced the chain length multifold, as detected by HPLC. The effect of monovalent cations on RNA synthesis was of the following order: Li+ > Na+ > K+. A similar effect was observed with the anions, enhancing catalysis in the following order: Cl- > Br- > I-. The montmorillonite-catalyzed RNA synthesis was not affected by hydrophobic or hydrophilic interactions. We thus show that prebiotic synthesis of RNA from its monomers was a simple process requiring only clay minerals and a small amount of salt.

  12. Prebiotic RNA Synthesis by Montmorillonite Catalysis

    Directory of Open Access Journals (Sweden)

    Sohan Jheeta

    2014-08-01

    Full Text Available This review summarizes our recent findings on the role of mineral salts in prebiotic RNA synthesis, which is catalyzed by montmorillonite clay minerals. The clay minerals not only catalyze the synthesis of RNA but also facilitate homochiral selection. Preliminary data of these findings have been presented at the “Horizontal Gene Transfer and the Last Universal Common Ancestor (LUCA” conference at the Open University, Milton Keynes, UK, 5–6 September 2013. The objective of this meeting was to recognize the significance of RNA in LUCA. We believe that the prebiotic RNA synthesis from its monomers must have been a simple process. As a first step, it may have required activation of the 5'-end of the mononucleotide with a leaving group, e.g., imidazole in our model reaction (Figure 1. Wide ranges of activating groups are produced from HCN under plausible prebiotic Earth conditions. The final step is clay mineral catalysis in the presence of mineral salts to facilitate selective production of functional RNA. Both the clay minerals and mineral salts would have been abundant on early Earth. We have demonstrated that while montmorillonite (pH 7 produced only dimers from its monomers in water, addition of sodium chloride (1 M enhanced the chain length multifold, as detected by HPLC. The effect of monovalent cations on RNA synthesis was of the following order: Li+ > Na+ > K+. A similar effect was observed with the anions, enhancing catalysis in the following order: Cl− > Br− > I−. The montmorillonite-catalyzed RNA synthesis was not affected by hydrophobic or hydrophilic interactions. We thus show that prebiotic synthesis of RNA from its monomers was a simple process requiring only clay minerals and a small amount of salt.

  13. Recycling dodecylamine intercalated vanadate nanotubes

    Energy Technology Data Exchange (ETDEWEB)

    Ferreira, Odair P., E-mail: odair@iqm.unicamp.br; Souza Filho, Antonio G., E-mail: agsf@fisica.ufc.br; Alves, Oswaldo L., E-mail: oalves@iqm.unicamp.b [Universidade Estadual de Campinas-UNICAMP, LQES - Laboratorio de Quimica do Estado Solido, Instituto de Quimica (Brazil)

    2010-01-15

    In this article, we report the thermal decomposition processes of dodecylamine intercalated vanadate nanotubes and their recycling process. Structural, vibrational, and morphological properties of the annealed samples were investigated by X-ray diffraction, infrared spectroscopy, and scanning electron microscopy, respectively. The data analysis unveiled that vanadate nanotubes (VONTs) decompose into nanoplates which is isostructural to xerogel, and finally to nanoparticle aggregates whose composition is a single V{sub 2}O{sub 5} bulk phase. These aggregates can be successfully recycled for converting the residues of decomposition process into vanadate nanotubes again.

  14. Monomers of cutin biopolymer: sorption and esterification on montmorillonite surfaces

    Science.gov (United States)

    Olshansky, Yaniv; Polubesova, Tamara; Chefetz, Benny

    2013-04-01

    One of the important precursors for soil organic matter is plant cuticle, a thin layer of predominantly lipids that cover all primary aerial surfaces of vascular plants. In most plant species cutin biopolymer is the major component of the cuticle (30-85% weight). Therefore cutin is the third most abundant plant biopolymer (after lignin and cellulose). Cutin is an insoluble, high molecular weight bio-polyester, which is constructed of inter-esterified cross linked hydroxy-fatty acids and hydroxyepoxy-fatty acids. The most common building blocks of the cutin are derivatives of palmitic acid, among them 9(10),16 dihydroxy palmitic acid (diHPA) is the main component. These fatty acids and their esters are commonly found in major organo-mineral soil fraction-humin. Hence, the complexes of cutin monomers with minerals may serve as model of humin. Both cutin and humin act as adsorption efficient domains for organic contaminants. However, only scarce information is available about the interactions of cutin with soil mineral surfaces, in particular with common soil mineral montmorillonite. The main hypothesize of the study is that adsorbed cutin monomers will be reconstituted on montmorillonite surface due to esterification and oligomerization, and that interactions of cutin monomers with montmorillonite will be affected by the type of exchangeable cation. Cutin monomers were obtained from the fruits of tomato (Lycopersicon esculentum). Adsorption of monomers was measured for crude Wyoming montmorillonites and montmorillonites saturated with Fe3+ and Ca2+. To understand the mechanism of monomer-clay interactions and to evaluate esterification on the clay surface, XRD and FTIR analyses of the montmorillonite-monomers complexes were performed. Our results demonstrated that the interactions of cutin monomers with montmorillonite are affected by the type of exchangeable cation. Isotherms of adsorption of cutin monomers on montmorillonites were fitted by a dual mode model of

  15. Investigation on interaction of DNA and several cationic surfactants with different head groups by spectroscopy, gel electrophoresis and viscosity technologies.

    Science.gov (United States)

    Guo, Qing; Zhang, Zhaohong; Song, Youtao; Liu, Shuo; Gao, Wei; Qiao, Heng; Guo, Lili; Wang, Jun

    2017-02-01

    In this study, the interaction between DNA and several cationic surfactants with different head groups such as ethyl hexadecyl dimethyl ammonium bromide (EHDAB), hexadecyl dimethyl benzyl ammonium chloride (HDBAC), and cetyl pyridinium bromide (CPB) were investigated by UV-vis absorption, fluorescence and circular dichroism (CD) spectroscopy, gel electrophoresis, and viscosity technologies. The results show that these cationic surfactants can interact with DNA and major binding modes are electrostatic and hydrophobic. Also, CPB and HDBAC molecules interact with DNA by partial intercalation, and CPB has slightly stronger intercalation than HDBAC, while EHDAB interacts with DNA by non-intercalation. The different head groups of the surfactant molecules can influence the interaction strength. CPB has the stronger interaction with DNA than the others. Moreover, surfactant concentration, the ratio of DNA and fluorescence probe, ionic strength can influence the interaction. The surfactants may interact with DNA by the competition reactions with BR for DNA-BR. The increase of ionic strength may favor the surface binding between DNA and surfactants to some extent. This work provides deep mechanistic insight on the toxicity of cationic surfactants with different head groups to DNA molecules.

  16. Methidium intercalator inserted into synthetic oligonucleotides.

    Energy Technology Data Exchange (ETDEWEB)

    Timofeev, E. N.; Smirnov, I. P.; Haff, L. A.; Tishchenko, E. I.; Mirzabekov, A. D.; Florentiev, V. L.; Center for Mechanistic Biology and Biotechnology; Engelhardt Inst. of Molecular Biology; PerSeptive BioSystems Inc.

    1996-01-01

    A new methidium intercalator phosphoramidite has been synthesized. Methidium incorporation into an oligonucleotide during the synthesis was confirmed by UV and MALDI TOF MS data. UV melting experiments showed enhanced stability of a duplex, containing internal methidium. Methidium phosphoramidite has been synthesized and used for insertion of intercalator into the deoxyoligonucleotides.

  17. Intercalation chemistry of zirconium 4-sulfophenylphosphonate

    Energy Technology Data Exchange (ETDEWEB)

    Svoboda, Jan [Institute of Macromolecular Chemistry, Academy of Sciences of the Czech Republic, Heyrovský Sq. 2, 162 06 Prague 6 (Czech Republic); Zima, Vítězslav, E-mail: vitezslav.zima@upce.cz [Institute of Macromolecular Chemistry, Academy of Sciences of the Czech Republic, Heyrovský Sq. 2, 162 06 Prague 6 (Czech Republic); Melánová, Klára [Institute of Macromolecular Chemistry, Academy of Sciences of the Czech Republic, Heyrovský Sq. 2, 162 06 Prague 6 (Czech Republic); Beneš, Ludvík [Faculty of Chemical Technology, University of Pardubice, 532 10 Pardubice (Czech Republic); Trchová, Miroslava [Institute of Macromolecular Chemistry, Academy of Sciences of the Czech Republic, Heyrovský Sq. 2, 162 06 Prague 6 (Czech Republic)

    2013-12-15

    Zirconium 4-sulfophenylphosphonate is a layered material which can be employed as a host for the intercalation reactions with basic molecules. A wide range of organic compounds were chosen to represent intercalation ability of zirconium 4-sulfophenylphosphonate. These were a series of alkylamines from methylamine to dodecylamine, 1,4-phenylenediamine, p-toluidine, 1,8-diaminonaphthalene, 1-aminopyrene, imidazole, pyridine, 4,4′-bipyridine, poly(ethylene imine), and a series of amino acids from glycine to 6-aminocaproic acid. The prepared compounds were characterized by powder X-ray diffraction, thermogravimetry analysis and IR spectroscopy and probable arrangement of the guest molecules in the interlayer space of the host is proposed based on the interlayer distance of the prepared intercalates and amount of the intercalated guest molecules. - Graphical abstract: Nitrogen-containing organic compounds can be intercalated into the interlayer space of zirconium 4-sulfophenylphosphonate. - Highlights: • Zirconium 4-sulfophenylphosphonate was examined as a host material in intercalation chemistry. • A wide range of nitrogen-containing organic compounds were intercalated. • Possible arrangement of the intercalated species is described.

  18. Molecular dynamics simulation of secondary sorption behavior of montmorillonite modified by single chain quaternary ammonium cations.

    Science.gov (United States)

    Zhao, Qian; Burns, Susan E

    2012-04-03

    Organoclays synthesized from single chain quaternary ammonium cations (QAC) ((CH(3))(3)NR(+)) exhibit different mechanisms for the sorption of nonpolar organic compounds as the length of the carbon chain is increased. The interaction between a nonpolar sorbate and an organoclay intercalated with small QACs has been demonstrated to be surface adsorption, while partitioning is the dominant mechanism in clays intercalated with long chain surfactants. This study presents the results of a molecular dynamics (MD) simulation performed to examine the sorption mechanisms of benzene in the interlayer of three organoclays with chain lengths ranging from 1 to 16 carbons: tetramethylammonium (TMA) clay; decyltrimethylammonium (DTMA) clay; and hexadecyltrimethylammonium (HDTMA) clay. The basis of the overall simulation was a combined force field of ClayFF and CVFF. In the simulations, organic cations were intercalated and benzene molecules were introduced to the interlayer, followed by whole system NPT and NVT time integration. Trajectories of all the species were recorded after the system reached equilibrium and subsequently analyzed. Simulation results confirmed that the arrangement of the surfactants controlled the sorption mechanism of organoclays. Benzene molecules were observed to interact directly with the clay surface in the presence of TMA cations, but tended to interact with the aliphatic chain of the HDTMA cation in the interlayer. The simulation provided insight into the nature of the adsorption/partitioning mechanisms in organoclays, and explained experimental observations of decreased versus increased uptake capacities as a function of increasing total organic carbon (TOC) for TMA clay and HDTMA clay, respectively. The transition of sorption mechanisms was also quantified with simulation of DTMA clay, with a chain length between that of TMA and HDTMA. Furthermore, this study suggested that at the molecular level, the controlling factor for the ultimate sorption

  19. Adsorption of mixed cationic-nonionic surfactant and its effect on bentonite structure

    Institute of Scientific and Technical Information of China (English)

    Yaxin Zhang; Yan Zhao; Yong Zhu; Huayong Wu; Hongtao Wang; Wenjing Lu

    2012-01-01

    The adsorption of cationic-nordonic mixed surfactant onto bentonite and its effect on bentonite structure were investigated.The objective was to improve the understanding of surfactant behavior on clay mineral for its possible use in remediation technologies of soil and groundwater contaminated by toxic organic compounds.The cationic surfactant used was hexadecylpyridinium bromide(HDPB),and the nonionic suffactant was Triton X-100(TX100).Adsorption of TX100 was enhanced significantly by the addition of HDPB,but this enhancement decreased with an increase in the fraction of the cationic surfactant.Part of HDPB was replaced by TX100 which decreased the adsorption of HDPB.However,the total adsorbed amount of the mixed surfactant was still increased substantially,indicating the synergistic effect between the cationic and nonionic surfactants.The surfactant-modified bentonite was characterized by Brunauer-Emmett-Teller specific surface area measurement,Fourier transform infrared spectroscopy,and thermogravimetric-derivative thermogravimetric/differential thermal analyses.Surfactant intercalation was found to decrease the bentonite specific surface area,pore volume,and surface roughness and irregularities,as calculated by nitrogen adsorption-desorption isotherms.The co-adsorption of the cationic and nonionic surfactants increased the ordering conformation of the adsorbed surfactants on bentonite,but decreased the thermal stability of the organobentonite system.

  20. Influence of Laurolactam Content on the Clay Intercalation of Polyamide 6,12/Clay Nanocomposites Synthesized by Open Ring Anionic Polymerization

    Directory of Open Access Journals (Sweden)

    E. N. Cabrera Álvarez

    2012-01-01

    Full Text Available In situ anionic homo- and copolymerization of caprolactam (CL and laurolactam (LL with sodium montmorillonite clay (NaMMT was carried out using two different initiators, sodium caprolactamate (CLNa and caprolactam magnesium bromide (CLMgBr. Degree of conversion and final molecular weight were used to assess the advancement and efficiency of the polymerization reaction and X-ray diffraction and electron microscopy were used to evaluate the sodium montmorillonite clay intercalation/exfoliation. The use of CLNa as initiator produced a higher conversion degree and molecular weight than the use of CLMgBr. Through DSC, it was observed that CLNa and CLMgBr tended to produce random and block copolymer structures, respectively, and either random or block, this eventually has an effect on the clay dispersion within the polymer matrix. In all cases, increasing the LL content produced a decrease in the conversion degree and in the molecular weight of the resulting polymer.

  1. Effects of Different Montmorillonite Nanoclay Loading on Cure Behavior and Properties of Diglycidyl Ether of Bisphenol A Epoxy

    Directory of Open Access Journals (Sweden)

    Alfred Tcherbi-Narteh

    2016-01-01

    Full Text Available The primary focus of this study was to understand the effects of different amounts of montmorillonite nanoclay (MMT loading on viscosity, cure behavior, reaction mechanism, and properties of diglycidyl ether of bisphenol A (DGEBA epoxy composites. Influence of 1–3 wt.% MMT on rheological and subsequent cure behavior of SC-15 epoxy resin was studied using nonisothermal and isothermal rheometry and differential scanning calorimetry (DSC. Rheological properties were influenced by different amounts of MMT at lower shear rates prior to and during curing. Cure reaction mechanism was unaffected by different MMT concentration; however heat and activation energy of reactions increased with increasing MMT loading. Samples with 2 wt.% MMT showed highest reaction rate constant, indicative of catalytic behavior. X-ray diffraction (XRD and transmission electron microscope (TEM revealed mainly intercalated microstructure throughout the MMT infused epoxy composite samples irrespective of the percent loading.

  2. Investigations into surfactant/gas hydrate relationship

    Energy Technology Data Exchange (ETDEWEB)

    Rogers, Rudy; Zhang, Guochang; Dearman, Jennifer; Woods, Charles [Swalm School of Chemical Engineering, Mississippi State University, Mississippi State, MS 39762 (United States)

    2007-03-15

    Gas hydrates have unique physical properties portending useful industrial applications of gas storage, gas separation, or water desalination. When gas hydrates were found in the early 1990s to occur naturally and abundantly in seafloors, three other primary interests and concerns emerged: potential new energy source, climate threat from their greenhouse gases, and seafloor instabilities. This paper presents research showing how anionic synthetic surfactants helped develop an industrial gas hydrate storage process for natural gas and how naturally-occurring in-situ anionic biosurfactants influence the formation and placement of gas hydrates in ocean sediments. The catalytic effects, mechanisms, and surface specificities imparted by synthetic surfactants in the gas storage process and imparted by biosurfactants in porous media are discussed. The Bacillus subtilis bacterium that is indigenous to gas hydrate mounds in the Gulf of Mexico was cultured in the laboratory. Its biosurfactant was separated and found to catalyze gas hydrates in porous media. The experiments indicate that seafloor-biosurfactants can be produced rapidly in-situ to achieve threshold concentrations whereby hydrates are promoted. The biosurfactants accumulate and promote hydrate formation on specific mineral surfaces such as sodium montmorillonite. (author)

  3. Intercalated hybrid graphite fiber composite

    Science.gov (United States)

    Gaier, James R. (Inventor)

    1993-01-01

    The invention is directed to a highly conductive lightweight hybrid material and methods of producing the same. The hybrid composite is obtained by weaving strands of a high strength carbon or graphite fiber into a fabric-like structure, depositing a layer of carbon onto the structure, heat treating the structure to graphitize the carbon layer, and intercalating the graphitic carbon layer structure. A laminate composite material useful for protection against lightning strikes comprises at least one layer of the hybrid material over at least one layer of high strength carbon or graphite fibers. The composite material of the present invention is compatible with matrix compounds, has a coefficient of thermal expansion which is the same as underlying fiber layers, and is resistant to galvanic corrosion in addition to being highly conductive. These materials are useful in the aerospace industry, in particular as lightning strike protection for airplanes.

  4. Nanocomposite PAAm/methyl cellulose/montmorillonite hydrogel: evidence of synergistic effects for the slow release of fertilizers.

    Science.gov (United States)

    Bortolin, Adriel; Aouada, Fauze A; Mattoso, Luiz H C; Ribeiro, Caue

    2013-08-01

    In this work, we synthesized a novel series of hydrogels composed of polyacrylamide (PAAm), methylcellulose (MC), and calcic montmorillonite (MMt) appropriate for the controlled release of fertilizers, where the components presented a synergistic effect, giving very high fertilizer loading in their structure. The synthesized hydrogel was characterized in relation to morphological, hydrophilic, spectroscopic, structural, thermal, and kinetic properties. After those characterizations, the application potential was verified through sorption and desorption studies of a nitrogenated fertilizer, urea (CO(NH2)2). The swelling degree results showed that the clay loading considerably reduces the water absorption capability; however, the hydrolysis process favored the urea adsorption in the hydrogel nanocomposites, increasing the load content according to the increase of the clay mass. The FTIR spectra indicated that there was incorporation of the clay with the polymeric matrix of the hydrogel and that incorporation increased the water absorption speed (indicated by the kinetic constant k). By an X-ray diffraction technique, good nanodispersion (intercalation) and exfoliation of the clay platelets in the hydrogel matrix were observed. Furthermore, the presence of the montmorillonite in the hydrogel caused the system to liberate the nutrient in a more controlled manner than that with the neat hydrogel in different pH ranges. In conclusion, excellent results were obtained for the controlled desorption of urea, highlighting the hydrolyzed hydrogels containing 50% calcic montmorillonite. This system presented the best desorption results, releasing larger amounts of nutrient and almost 200 times slower than pure urea, i.e., without hydrogel. The total values of nutrients present in the system show that this material is potentially viable for application in agriculture as a nutrient carrier vehicle.

  5. COMPARISON OF POLYAMIDE 66/MONTMORILLONITE NANOCOMPOSITES PREPARED FROM POLYAMIDE 6 AND POLYAMIDE 66 BASED MASTER-BATCHES

    Institute of Scientific and Technical Information of China (English)

    Qing-quan Yang; Zhao-xia Guo; Jian Yu

    2008-01-01

    Two master-batches,polyamide 66 (PA66)/organo-montmorillonite (OMMT) and polyamide 6 (PA6)/OMMT,prepared by melt compounding with methyl methacrylate (MMA) as co-intercalation agent,have been used to prepare nearly exfoliated PA66/montmorillonite (MMT) nanocomposites.The resulting nanocomposites are compared in view of their morphology and properties.Nano-scale dispersion of OMMT is realized in both types of nanocomposites,as revealed by XRD,TEM and Molau tests.PA66/MMT nanocomposites having superior mechanical properties and heat distortion temperature (HDT) can be obtained from either PA66/OMMT or PA6/OMMT master-batch.Those from PA6/OMMT have lower tensile and flexural properties,and HDT than those from PA66/OMMT due to the presence of less stiff and less thermal resistant PA6.The crystallization behavior and crystal structure of the matrix in both types of PA66/MMT nanocomposites are also investigated by DSC and WAXD.

  6. Synthesis and characterization of carboxymethyl cellulose/organic montmorillonite nanocomposites and its adsorption behavior for Congo Red dye

    Directory of Open Access Journals (Sweden)

    Min-min WANG

    2013-07-01

    Full Text Available A series of carboxymethyl cellulose/organic montmorillonite (CMC/OMMT nanocomposites with different weight ratios of carboxymethyl cellulose (CMC to organic montmorillonite (OMMT were synthesized under different conditions. The nanocomposites were characterized by the Fourier transform infrared (FT-IR spectrophotometer, X-ray diffraction (XRD method, transmission electron microscope (TEM, scanning electron microscope (SEM, and thermal gravimetric (TG analysis. The results showed that the introduction of CMC may have different influences on the physico-chemical properties of OMMT and intercalated-exfoliated nanostructures were formed in the nanocomposites. The effects of different reaction conditions on the adsorption capacity of samples for Congo Red (CR dye were investigated by controlling the amount of hexadecyl trimethyl ammonium bromide (CTAB, the weight ratio of CMC to OMMT, the reaction time, and the reaction temperature. Results from the adsorption experiment showed that the adsorption capacity of the nanocomposites can reach 171.37 mg/g, with the amount of CTAB being 1.0 cation exchange capacity (CEC of MMT, the weight ratio of CMC to OMMT being 1?1, the reaction time being 6 h, and the reaction temperature being 60℃. The CMC/OMMT nanocomposite can be used as a potential adsorbent to remove CR dye from an aqueous solution.

  7. Nontronite and Montmorillonite as Nutrient Sources for Life on Mars

    Science.gov (United States)

    Mickol, R. L.; Craig, P. I.; Kral, T. A.

    2016-05-01

    Methanogens were grown in media containing bicarbonate buffer, nontronite or montmorillonite clay, and hydrogen gas. No other nutrients were added. These results suggest that martian clays may provide adequate nutrients to support organism growth.

  8. Effect of montmorillonite on arsenic accumulation in common carp

    African Journals Online (AJOL)

    Yomi

    2012-02-01

    Feb 1, 2012 ... The effect of montmorillonite (MMT) on dietary arsenic (As(III)) accumulation in tissues of common carp ... Owing to its toxic potential to humans, it is a high priority ... various heavy metal ions (Bhattacharyya and Gupta,. 2008).

  9. Cadmium adsorption in montmorillonite as affected by glyphosate

    Institute of Scientific and Technical Information of China (English)

    WANG Yu-jun; ZHOU Dong-mei; LUO Xiao-san; SUN Rui-juan; CHEN Huai-man

    2004-01-01

    Behaviors of soil heavy metals are often affected by coexisting herbicides due to their physical and chemical interaction. Effect of glyphosate, an herbicide containing -PO32- and -COOH groups, on cadmium adsorption in montmorillonite was studied in detail. The results showed that cadmium adsorption quantity in montmorillonite increased with increasing soil solution pH and cadmium concentration as usual, but decreased with glyphosate, which is due to the formation of a low affinity complex of Cd and glyphosate and decreasing solution pH induced by glyphosate addition. When the equilibrium solution pH was below 6.7, glyphosate has little effect on cadmium adsorption, but when the equilibrium solution pH was above 6.7, glyphosate significantly decreased cadmium adsorption quantity in montmorillonite. In addition, the adding order of Cd and glyphosate also influenced Cd adsorption quantity in montmorillonite.

  10. Caffeine adsorption of montmorillonite in coffee extracts.

    Science.gov (United States)

    Shiono, Takashi; Yamamoto, Kenichiro; Yotsumoto, Yuko; Yoshida, Aruto

    2017-08-01

    The growth in health-conscious consumers continues to drive the demand for a wide variety of decaffeinated beverages. We previously developed a new technology using montmorillonite (MMT) in selective decaffeination of tea extract. This study evaluated and compared decaffeination of coffee extract using MMT and activated carbon (AC). MMT adsorbed caffeine without significant adsorption of caffeoylquinic acids (CQAs), feruloylquinic acids (FQAs), dicaffeoylquinic acids (di-CQAs), or caffeoylquinic lactones (CQLs). AC adsorbed caffeine, chlorogenic acids (CGAs) and CQLs simultaneously. The results suggested that the adsorption selectivity for caffeine in coffee extract is higher in MMT than AC. The caffeine adsorption isotherms of MMT in coffee extract fitted well to the Langmuir adsorption model. The adsorption properties in coffee extracts from the same species were comparable, regardless of roasting level and locality of growth. Our findings suggest that MMT is a useful adsorbent in the decaffeination of a wide range of coffee extracts.

  11. ANALYSIS DEGRADATION OF POLYSTYRENE WITH MONTMORILLONITE NANOFILLERS

    Directory of Open Access Journals (Sweden)

    Maria Mihalikova

    2014-01-01

    Full Text Available The paper is focused on the experimental investigation of the montmorillonite nanofillers effect on deformation properties of polystyrene KRASTEN 171. In some cases, combination of a low amount of clay with dispersed polymeric phase may cause synergistic effects leading to very fair balance of mechanical behaviour. This seems to be a consequence of complex influencing the multiphase system by clay such as modification of components (reinforcement and parameters of the interface accompanied by influencing the dynamic phase behaviour, i.e., the compactibilizing effect. The paper analyses the effect of nanocomposites and type of the material on the individual measured parameters, relations between them, strength and deformation behaviour. Deformation was evaluated by non-contact videoextensometry method

  12. Montmorillonite-induced Bacteriophage φ6 Disassembly

    Science.gov (United States)

    Trusiak, A.; Gottlieb, P.; Katz, A.; Alimova, A.; Steiner, J. C.; Block, K. A.

    2012-12-01

    It is estimated that there are 1031 virus particles on Earth making viruses an order of magnitude more prevalent in number than prokaryotes with the vast majority of viruses being bacteriophages. Clays are a major component of soils and aquatic sediments and can react with RNA, proteins and bacterial biofilms. The clays in soils serve as an important moderator between phage and their host bacteria, helping to preserve the evolutionary balance. Studies on the effects of clays on viral infectivity have given somewhat contradictory results; possibly a consequence of clay-virus interactions being dependent on the unique structure of particular viruses. In this work, the interaction between montmorillonite and the bacteriophage φ6 is investigated. φ6 is a member of the cystovirus family that infects Pseudomonas syringe, a common plant pathogen. As a member of the cystovirus family with an enveloped structure, φ6 serves as a model for reoviruses, a human pathogen. Experiments were conducted with φ6 suspended in dilute, purified homoionic commercial-grade montmorillonite over a range of virus:clay ratios. At a 1:100000 virus:clay ratio, the clay reduced viral infectivity by 99%. The minimum clay to virus ratio which results in a measurable reduction of P. syringae infection is 1:1. Electron microscopy demonstrates that mixed suspensions of smectite and virus co-aggregate to form flocs encompassing virions within the smectite. Both free viral particles as well as those imbedded in the flocs are seen in the micrographs to be missing the envelope- leaving only the nucleocapsid (NC) intact; indicating that smectite inactivates the virus by envelope disassembly. These results have strong implications in the evolution of both the φ6 virus and its P. syringae host cells. TEM of aggregate showing several disassembled NCs.

  13. Influence of montmorillonite on antimicrobial activity of tetracycline and ciprofloxacin

    Science.gov (United States)

    Lv, Guocheng; Pearce, Cody W.; Gleason, Andrea; Liao, Libing; MacWilliams, Maria P.; Li, Zhaohui

    2013-11-01

    Antibiotics are used not only to fight infections and inhibit bacterial growth, but also as growth promotants in farm livestock. Farm runoff and other farm-linked waste have led to increased antibiotic levels present in the environment, the impact of which is not completely understood. Soil, more specifically clays, that the antibiotic contacts may alter its effectiveness against bacteria. In this study a swelling clay mineral montmorillonite was preloaded with antibiotics tetracycline and ciprofloxacin at varying concentrations and bioassays were conducted to examine whether the antibiotics still inhibited bacterial growth in the presence of montmorillonite. Escherichia coli was incubated with montmorillonite or antibiotic-adsorbed montmorillonite, and then the number of viable bacteria per mL was determined. The antimicrobial activity of tetracycline was affected in the presence of montmorillonite, as the growth of non-resistant bacteria was still found even when extremely high TC doses were used. Conversely, in the presence of montmorillonite, ciprofloxacin did inhibit E. coli bacterial growth at high concentrations. These results suggest that the effectiveness of antimicrobial agents in clayey soils depends on the amount of antibiotic substance present, and on the interactions between the antibiotic and the clays in the soil, as well.

  14. Synthesis of organic rectorite with novel Gemini surfactants for copper removal

    Energy Technology Data Exchange (ETDEWEB)

    Han, Guocheng; Han, Yang [State Key Laboratory of Pulp and Paper Engineering, South China University of Technology, Guangzhou 510640 (China); Wang, Xiaoying, E-mail: xyw@scut.edu.cn [State Key Laboratory of Pulp and Paper Engineering, South China University of Technology, Guangzhou 510640 (China); Liu, Shijie, E-mail: sjliu@163.com [State Key Laboratory of Pulp and Paper Engineering, South China University of Technology, Guangzhou 510640 (China); Department of Paper and Bioprocess Engineering, State University of New York, College of Environmental Science and Forestry, 1 Forestry Drive, Syracuse, NY 13210 (United States); Sun, Runcang [State Key Laboratory of Pulp and Paper Engineering, South China University of Technology, Guangzhou 510640 (China); China Beijing Key Laboratory of Lignocellulosic Chemistry, Beijing Forestry University, Beijing 100083 (China)

    2014-10-30

    Graphical abstract: Three Gemini surfactants showed stronger rapid intercalation capacity into rectorite and behaved better on Cu{sup 2+} removal than two single-chain surfactants, which were positive to their increasing amount and chain length. - Highlights: • Modification of rectorite (REC) with several surfactants was performed in 1 h. • The arrangement of Gemini surfactants in REC layers was discussed. • All ORECs displayed better adsorption capacities on Cu{sup 2+} than pure REC. • Gemini-REC behaved better than single-chain surfactant modified REC on Cu{sup 2+} removal. • The adsorption capacity was positive to the amount and chain length of surfactant. - Abstract: Three novel Gemini surfactants were used to prepare organic rectorite (OREC) under microwave irradiation, in comparison with single-chain surfactant ester quaternary ammonium salt (EQAS) and cetyltrimethyl ammonium bromide (CTAB). The structure and morphology of OREC were characterized by XRD, BET, FT-IR, TEM and TGA. The removal of Cu{sup 2+} on OREC from aqueous solution was performed. The results reveal that Gemini surfactants modified REC had larger interlayer distance and higher surface area than single-chain surfactants EQAS and CTAB, and the increasing amount or chain length of Gemini surfactants led to larger layer spacing and higher adsorption capacities. The adsorption behavior of Gemini surfactant modified REC can be better described by Freundlich adsorption isotherm model, with a maximum adsorption capacity of 15.16 mg g{sup −1}. The desorption and regeneration experiments indicate good reuse property of Gemini modified REC adsorbent. Therefore, this study may widen the utilization of Gemini surfactants modified layered silicates.

  15. Structure-Property Relationships in Intercalated Graphite.

    Science.gov (United States)

    1984-10-15

    2% 293 (1984). 45. "Raman Microprobe Studies of the Structure of SbCls-Graphite Intercalation Compounds’, L.E. McNeil, J. Steinbeck , L. Salamanca-Riba...Using the Rutherford Backscattering-Channeling Teachnique’, G. Braunstein, B. Elman, J. Steinbeck , M.S. Dresseihaus, T. Venkatesan and B. Wilkens, to be...8217Razuan Mcroprobe Observation of Intercalate Contraction In Graphite Inter- calation Compounds’, L.E. McNeil, J. Steinbeck , L. Salamancar-Riba, and G

  16. Adsorption of As on hydroxy-Fe-montmorillonite complexes

    Institute of Scientific and Technical Information of China (English)

    LIAO Libing; Donald G. Fraser

    2005-01-01

    Arsenate has high affinity for soluble hydroxy-Fe species and Fe-oxyhydroxide precipitates. In addition, the hydrolysis of Fe(III) and the growth of the initially precipitated Fe(III) phases are strongly influenced by the presence of montmorillonite. In this paper, the adsorption of As onto various hydroxy-Fe-montmorillonite (H-F-M) complexes was studied. Three systems of samples were prepared by mixing montmorillonite, hydroxy-Fe and arsenate in different sequences: (1) Prior mixing of montmorillonite and hydroxy-Fe before the addition of arsenate; (2) prior mixing of hydroxy-Fe and arsenate before the addition of montmorillonite; and (3) prior mixing of montmorillonite and arsenate before the addition of hydroxy-Fe. For each system, the effects of pH, ionic strength, temperature, initial Fe and As concentrations and adsorption duration on the overall uptake of As by H-F-M complexes were studied. Results showed that the uptake of As increased with increasing pH, temperature, initial Fe concentration and adsorption duration, and decreased with increasing ionic strength and initial As concentration to different extents for the three systems. The variation of the As uptake of H-F-M complexes with pH in the range of study is opposite to that reported previously for Fe-O-H systems in the absence of montmorillonite and similar to that reported for montmorillonite in the absence of hydroxy-Fe. The marked influence of ionic strength on the As uptake of H-F-M complexes indicates that outer-sphere complexation plays an important role. This is quite different from the adsorption of As on the surface of either Fe-oxyhydroxides or montmorillonite alone in which inner-sphere complexation dominates. Under all experimental conditions, the H-F-M complexes studied displayed a very strong affinity for As, among which system 2 had the highest As adsorption capacity and system 1 the lowest. The authors attribute this to the differences in mixing sequence which resulted in more hydroxy

  17. Surfactants in tribology

    CERN Document Server

    Biresaw, Girma

    2014-01-01

    Surface science and tribology play very critical roles in many industries. Manufacture and use of almost all consumer and industrial products rely on the application of advanced surface and tribological knowledge. The fourth in a series, Surfactants in Tribology, Volume 4 provides an update on research and development activities connecting surfactants and tribological phenomena. Written by renowned subject matter experts, the book demonstrates how improved design of surfactants can be harnessed to control tribological phenomena. Profusely illustrated and copiously referenced, the chapters also

  18. Effects of antistatic agent on the mechanical, morphological and antistatic properties of polypropylene/organo-montmorillonite nanocomposites

    Directory of Open Access Journals (Sweden)

    2009-02-01

    Full Text Available Polypropylene (PP and PP/organo-montmorillonite (OMMT compounds containing antistatic agent (3, 6 and 9 wt% were prepared using co-rotating twin screw extruder followed by injection molding. PP/OMMT composites were prepared by mixing of PP, OMMT and maleated PP (PPgMAH. The mechanical properties of PP blends and PP/OMMT nanocomposites were studied by tensile and impact tests. The effect of antistatic agent (AA on the surface resistivity of PP and PP/OMMT nanocomposites were studied. The morphological properties of PP blends and PP/OMMT nanocomposites were characterized by using field emission scanning electron microscopy (FESEM. The intercalation of OMMT silicates layer in PP nanocomposites was characterized using X-ray diffraction (XRD. The impact strength of PP blends and PP/OMMT nanocomposites did not vary significantly by the addition of antistatic agent. The tensile modulus and tensile strength of PP/OMMT nanocomposites were slightly decreased with the increasing loading of antistatic agents. From FESEM analysis, the dispersion of antistatic agent in the PP matrix can be revealed. In addition, the surface resistivity of PP/OMMT compound was affected by the loading of antistatic agent. XRD results indicated the formation of intercalated nanocomposites for PP/OMMT/AA.

  19. POLYMERIC SURFACTANT STRUCTURE

    Institute of Scientific and Technical Information of China (English)

    P.M. Saville; J.W. White

    2001-01-01

    Polymeric surfactants are amongst the most widespread of all polymers. In nature, proteins and polysaccharides cause self organization as a result of this surfactancy; in industry, polymeric surfactants play key roles in the food, explosives and surface coatings sectors. The generation of useful nano- and micro-structures in films and emulsions as a result of polymer amphiphilicity and the application of mechanical stress is discussed. The use of X-ray and neutron small angle scattering and reflectivity to measure these structures and their dynamic properties will be described. New results on linear and dendritic polymer surfactants are presented.

  20. Dendrimer-surfactant interactions.

    Science.gov (United States)

    Cheng, Yiyun; Zhao, Libo; Li, Tianfu

    2014-04-28

    In this article, we reviewed the interactions between dendrimers and surfactants with particular focus on the interaction mechanisms and physicochemical properties of the yielding dendrimer-surfactant aggregates. In order to provide insight into the behavior of dendrimers in biological systems, the interactions of dendrimers with bio-surfactants such as phospholipids in bulk solutions, in solid-supported bilayers and at the interface of phases or solid-states were discussed. Applications of the dendrimer-surfactant aggregates as templates to guide the synthesis of nanoparticles and in drug or gene delivery were also mentioned.

  1. Montmorillonite stability. With special respect to KBS-3 conditions

    Energy Technology Data Exchange (ETDEWEB)

    Karnland, Ola; Birgersson, Martin [Clay Technology AB, Lund (Sweden)

    2006-08-15

    The basic advantageous properties, e.g. low hydraulic conductivity and high swelling pressure, of the bentonite buffer in a KBS- repository stem from a strong interaction between water and the montmorillonite mineral in the bentonite. Minerals similar in structure but with substantially lower mineral-water interaction exist in nature. Transformations from montmorillonite to such minerals are observed e.g. in burial diagenesis and in contact metamorphism. A thermodynamic consideration confirms that medium and low charged montmorillonite is not in chemical equilibrium with quartz. From a safety assessment perspective it is therefore of vital importance to quantify the montmorillonite transformation under KBS- conditions. Silica release from the montmorillonite tetrahedral layers is the initial process for several possible transformations. Replacement of silica by aluminum increases the layer charge but maintains the basic atomic structure. A sufficiently high layer charge results in an irreversible collapse of the clay-water structure, i.e. a non-swelling mineral is formed. Compared to other cations, potassium as counter ion leads to a collapse at lower layer charge and the produced phase is generally termed illite. Montmorillonite-to-illite transformation is the most frequently found alteration process in nature. Three different kinetic illitization models are reviewed and the model proposed by Huang et al. is considered the most suitable for quantification in a KBS- repository, since the kinetic rate expression and its associated parameters are systematically determined by laboratory work. The model takes into account temperature, montmorillonite fraction and potassium concentration, but do not include relevant parameters such as pH, temperature gradients and water content. Calculations by use of the Huang illitization model applied for repository conditions yield insignificant montmorillonite transformation also under very pessimistic assumptions. Other non

  2. Surfactant Sector Needs Urgent Readjustment

    Institute of Scientific and Technical Information of China (English)

    Huang Hongzhou

    2007-01-01

    @@ Surfactant industrial system has been basically established After 50 years' development, China has already established a surfactant industrial system with a relatively complete product portfolio and can produce 4714 varieties of surfactants in cationic,anionic, nonionic and amphoteric categories.

  3. Hybrid materials: Magnetite-Polyethylenimine-Montmorillonite, as magnetic adsorbents for Cr(VI) water treatment.

    Science.gov (United States)

    Larraza, Iñigo; López-Gónzalez, Mar; Corrales, Teresa; Marcelo, Gema

    2012-11-01

    Hybrid materials formed by the combination of a sodium rich Montmorillonite (MMT), with magnetite nanoparticles (40 nm, Fe(3)O(4) NPs) coated with Polyethylenimine polymer (PEI 800 g/mol or PEI 25000 g/mol) were prepared. The intercalation of the magnetite nanoparticles coated with PEI among MMT platelets was achieved by cationic exchange. The resulting materials presented a high degree of exfoliation of the MMT sheets and a good dispersion of Fe(3)O(4) NPs on both the surface and among the layers of MMT. The presence of amine groups in the PEI structure not only aids the exfoliation of the MMT layers, but also gives to the hybrid material the necessary functionality to interact with heavy metals. These hybrid materials were used as magnetic sorbent for the removal of hexavalent chromium from water. The effect that pH, Cr(VI) concentration, and adsorbent material composition have on the Cr(VI) removal efficiency was studied. A complete characterization of the materials was performed. The hybrid materials showed a slight dependence of the removal efficiency with the pH in a wide range (1-9). A maximum amount of adsorption capacity of 8.8 mg/g was determined by the Langmuir isotherm. Results show that these hybrid materials can be considered as potential magnetic adsorbent for the Cr(VI) removal from water in a wide range of pH.

  4. Effect of Orally Administered Glutathione-Montmorillonite Hybrid Systems on Tissue Distribution

    Directory of Open Access Journals (Sweden)

    Miri Baek

    2012-01-01

    Full Text Available An ubiquitous tripeptide, glutathione (GSH, is assigned a role in detoxification, activation of immune system, intermediary metabolism, transport, and protection of cells against free radicals or reactive oxygen species. However, instability of orally administered GSH in gastrointestinal (GI tract leads to low absorption and low bioavailability in tissues. In this study, we attempted to synthesize GSH-montmorillonite (MMT hybrid systems by intercalating GSH into the interlayers of a cationic clay delivery carrier, MMT, to improve GSH bioavailability at the systemic level. Polymer coating of the hybrid with polyvinylacetal diethylaminoacetate (AEA was further performed to obtain better stability. Synthetic condition of both GSH-MMT and AEA-GSH-MMT hybrids was optimized, and then GSH-delivery efficiency was evaluated in various organs after oral administration in normal as well as GSH-deficient mice. The present GSH-MMT hybrids remarkably enhanced GSH concentration in the plasma, heart, kidney, and liver, especially when AEA-GSH-MMT hybrid was administered under GSH-deficient condition. Moreover, both hybrids did not induce acute oral toxicity up to 2000 mg/kg, suggesting their great potential for pharmaceutical application.

  5. PROPERTIES AND MORPHOLOGY OF UNSATURATED POLYESTER/ACRYLATE-TERMINATED POLYURETHANE/ORGANO-MONTMORILLONITE NANOCOMPOSITES

    Institute of Scientific and Technical Information of China (English)

    Chang-jiang You; Jin-guo Xu; Song Xi; Xiao-xia Duan; Jie Shen; De-min Jia

    2005-01-01

    Unsaturated polyester resin (UPR)/acrylate-terminated polyurethane (ATPU)/organo-modified montmorillonite (OMMT) nanocomposites were prepared by the in situ intercalative polymerization method. Samples were prepared by the sequential mixing, i.e. mixture of the ATPU and styrene (S) and OMMT were prepared in the first step; UPR was then added to the pre-intercalates of ATPU/S/OMMT. Results indicate that the mechanical properties and thermal properties of UPR/ATPU/OMMT nanocomposites greatly depend on the amount of ATPU and OMMT. Results show that the addition of ATPU could increase the impact strength of UPR/ATPU composites, but the tensile strength, flexural strength and heat resistance of the materials are obviously decreased. When the weight ratio between UPR, ATPU and OMMT were 82:15:3,the impact strength and heat distortion-temperature of nanocomposite were greatly improved, meanwhile there was little change for other properties of the nanocomposites. The synergistic enhancement effects of ATPU and OMMT on the composites were observed. The structures and morphology of the composites were investigated by X-ray diffraction,scanning electron microscopy and transmission electron microscopy.

  6. Characterization of Pullulan/Chitosan Oligosaccharide/Montmorillonite Nanofibers Prepared by Electrospinning Technique.

    Science.gov (United States)

    Rabbani, Mohammad Mahbub; Yang, Seong Baek; Park, Soo-Jin; Oh, Weontae; Yeum, Jeong Hyun

    2016-06-01

    Pullulan/Chitosan oligosaccharide (COS)/Montmorillonite (MMT) hybrid nanofibers were electrospun from their aqueous solution using different Pullulan/COS mass ratios and variable amounts of MMT. The effects of Pullulan/COS mass ratios and MMT contents on the morphologies and properties of PulluIan/COS/MMT hybrid nanofibers were investigated. The obtained nanofibers were characterized with field emission-scanning electron microscopy (FE-SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), thermo gravimetric analysis (TGA), and tensile strength measurement. The Pullulan/COS mass ratio and MMT contents significantly influence the morphologies and properties of the Pullulan/COS/MMT hybrid nanofibers. Higher Pullulan contents than COS contents forms uniform and bead free nanofibers. The addition of COS to Pullulan improves the thermal stability of Pullulan/COS blend nanofibers. The incorporation of MMT to the Pullulan/COS/MMT hybrid nanofibers increase their fiber diameter, improves their thermal stability and tensile strength. These morphological changes and property enhancement depend on the amount of MMT added. The XRD and TEM results suggest the coexistence of Pullulan, COS and MMT within polymer matrix through intercalation of polymer chain between silicate layers forming well-ordered multiplayer morphology with alternating polymeric and silicate layers.

  7. Preparation and characterisation of polyamide 11/montmorillonite (MMT) nanocomposites for use in angioplasty balloon applications

    Energy Technology Data Exchange (ETDEWEB)

    Halim, Khairul Anwar A. [Department of Polymer Engineering, Athlone Institute of Technology, Athlone (Ireland); School of Materials Engineering, Universiti Malaysia Perlis, Perlis (Malaysia); Farrell, Joseph B. [Department of Polymer Engineering, Athlone Institute of Technology, Athlone (Ireland); Kennedy, James E., E-mail: jkennedy@ait.ie [Department of Polymer Engineering, Athlone Institute of Technology, Athlone (Ireland)

    2013-12-16

    With increased demands on catheter balloon functionality, there is an emphasis to blend new materials which can improve mechanical performance. Polymer nanocomposites were prepared by melt blending polyamide 11 (PA 11) with organically modified montmorillonite nanoclay. The effects of incorporating the nanoclay on the short-term mechanical properties of PA 11 were assessed using a design of experiments (DoEs) approach. X-ray diffraction (XRD), transmission electron microscopy (TEM), differential scanning calorimetry (DSC) and dynamic mechanical thermal analysis techniques (DMA) were used to characterise the morphology of the nanocomposites. Design of experiments studies revealed that the optimum nanocomposites properties can be achieved by carefully controlling the melt compounding parameters. XRD and TEM data proved that exfoliated clay morphologies existed within the matrix at low clay loading (2%). Whereas the interaction between the polymer matrix and nanoclay was quantified in the DMA spectra, showed a significant increase in storage modulus (up to 80%). The reinforcing effect of nanoclay within the PA 11 was further investigated using mechanical testing, where significant increases in the ultimate tensile strength and strain at break of reinforced tri-layer balloon tubing were observed. - Highlights: • TEM reveals the coexistence of exfoliated and intercalated nanostructures. • Isothermal crystallisation studies found that the nano-clays reduced the crystallisation time. • Significant increase in the storage modulus was due to the reinforcing effect of the nano-clay platelets. • It was observed that the activation energy values decreased due to the presence of nanoclay.

  8. Spectroscopic study of silver halides in montmorillonite and their antibacterial activity.

    Science.gov (United States)

    Sohrabnezhad, Sh; Rassa, M; Mohammadi Dahanesari, E

    2016-10-01

    In this study silver halides (AgX, X=Cl, Br, I) in montmorillonite (MMT) were prepared by dispersion method in dark. AgNO3 was used as a silver precursor. The nanocomposites (NCs) (AgX-MMT) were characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), transmission electron microscopy (TEM), and ultraviolet-visible diffuse reflectance spectroscopy (DRS). The powder X-ray diffraction showed intercalation of AgCl and AgBr nanoparticles (NPs) into the clay interlayer space. The diffuse reflectance spectra indicated a broad surface plasmon resonance (SPR) absorption band in the visible region for AgCl-MMT and AgBr-MMT NCs, resulting of metallic Ag nanoparticles (Ag NPs). But the results were opposite in case of AgI-MMT NC. The antibacterial activity of NCs was investigated against Gram-positive bacteria, i.e., Staphylococcus aureus and Micrococcus luteus and Gram-negative bacteria, i.e., Escherichia coli, Pseudomonas aeruginosa, by the well diffusion method. The antibacterial effects on Staphylococcus aureus, Micrococcus luteus and Escherichia coli decrease in the order: AgCl-MMT>AgBr-MMT>AgI-MMT. No antibacterial activity was detected for Pseudomonas aeruginosa.

  9. Preparation and Properties of Gelatin-Chitosan/Montmorillonite Drug-loaded Microspheres

    Institute of Scientific and Technical Information of China (English)

    ZHENG Junping; SHAN Jiahui; FAN Zhaoming; YAO Kangde

    2011-01-01

    A kind of slow release drug-loaded microspheres were prepared with gelatin,chitosan and montmorillonite(MMT)by an emulsification/chemical cross-linking method using glutaraldehyde as cross-linking agent and acyclovir as model drug.The microspheres were characterized by X-ray diffraction(XRD),Fourier transform infrared(FT-IR)and scanning electron microscopy(SEM),respectively.The morphology,drug content,encapsulation efficiency and drug-release behavior were investigated with different MMT contents.The experimental results indicated that intercalated microspheres could be prepared,the morphology of microspheres was markedly affected by MMT.The glomeration performance of uncross-linked microspheres was improved because of the physical cross-linking of MMT.Drug content and encapsulation efficiency were decreased when increased the content of MMT,but burst release and the drug release were significantly decreased with the addition of MMT.Effective physical cross-linking could be formed when added MMT,and MMT could reduce the content of toxic chemical cross-linking agents.

  10. The Effect of Multiple Extrusions on the Properties of Montmorillonite Filled Polypropylene

    Directory of Open Access Journals (Sweden)

    Laurens Delva

    2014-12-01

    Full Text Available Nanocomposites have attracted a great deal of interest during recent years. Much research has been conducted towards the incorporation of clay particles in a polypropylene matrix. However, the effect of extrusion reprocessing on the material properties has not been studied in depth. In this study, composites of polypropylene (PP reinforced with organic modified montmorillonite (MMT (4 wt% and coupling agent were subjected to 15 extrusion cycles. The materials were characterized by melt flow index (MFI, plate-plate rheometry, tensile testing and impact measurements, differential scanning calorimetry (DSC, X-ray diffraction (XRD and scanning electron microscopy (SEM. The results showed an improved intercalation of the MMT clay in the first few extrusions, thus improving the mechanical properties. Increasing the processing steps furthermore lead to a decrease in elastic modulus and impact strength, which was attributed to a reduction in matrix-filler interaction, most probably caused by organoclay degradation as shown by thermogravimetric analysis (TGA. The results of this study provide a useful insight in either the recycling of PP/MMT waste streams or the use of clay particles as a strengthening filler agent in the recycling process of different polymer waste streams.

  11. Interaction of Auramine O with montmorillonite clays

    Energy Technology Data Exchange (ETDEWEB)

    Ferreira, Avelardo U.C.; Poli, Alessandra L.; Gessner, Fergus; Neumann, Miguel G. [Instituto de Química de São Carlos, Universidade de São Paulo, Caixa Postal 780, 13560-970 São Carlos SP (Brazil); Schmitt Cavalheiro, Carla C., E-mail: carla@iqsc.usp.br [Instituto de Química de São Carlos, Universidade de São Paulo, Caixa Postal 780, 13560-970 São Carlos SP (Brazil)

    2013-04-15

    The spectroscopic behaviour of Auramine O (AuO) in aqueous suspensions of montmorillonite clays was studied using absorption and static and dynamic fluorescence techniques. The fluorescence of Auramine O increases immediately after mixing the dye solution with the suspension of clay due to its adsorption on the external surface of the clays, which restricts the torsional molecular motion of Auramine. At longer times, the dye molecules migrate into the interlamellar region of the clay particles. Aggregation of the dye molecules can occur in the interlayer region, leading to the decrease of the fluorescence emission. The fluorescence quantum yields (Φ{sub F}) of AuO on the natural montmorillonites SAz-1, SWy-1, Syn-1 and Laponite clays were 0.015, 0.007, 0.016 and 0.017, respectively. These values are higher than the Φ{sub F} of AuO in aqueous solution and are of the same order of magnitude of the Φ{sub F} found for viscous solvents such as n-hexanol and n-heptanol (0.014 and 0.015). Time-resolved fluorescence spectroscopy studies of adsorbed Auramine on clays revealed multi-exponential decays with components in the 25–36, 219–362 and 1300–1858 ps ranges. The short-lived components can be attributed to species bound to external surface and the longer lifetime is assigned to dye molecules in interlayer spaces interacting strongly with the clay. It seems clear that the binding of Auramine to clays causes a significant reduction of the rate of internal conversion that does involve rotational diffusion, so that the clay will be locked in a conformational geometry unfavourable for internal conversion. -- Highlights: ► Auramine O was dissolved in dispersions of different clays. ► The fluorescence quantum yields were higher than in aqueous solution. ► Decrease of the emission and triexponential decays were observed on SAz-1, LapRDS and SYn-1. ► On Swy-1 the decrease was slower and the decay monoexponential. ► The dye produces aggregates on the internal

  12. Formation of stable nanocomposite clays from small peptides reacted with montmorillonite and illite-smectite mixed layer clays

    Science.gov (United States)

    Block, K. A.; Katz, A.; LeBlanc, J.; Peña, S.; Gottlieb, P.

    2015-12-01

    Understanding how organic compounds interact with clay minerals and which functional groups result in the strongest bonds is pivotal to achieving a better understanding of how mineral composition affects the residence time of carbon and nitrogen in soils. In this work, we describe how small peptides derived from tryptone casein digest are dissolved and suspended with clay minerals to examine the nature of OM adsorption to mineral surfaces and the resulting effect on clay mineral structure. XRD analyses indicate that peptides intercalation results in expansion of the d001 spacing of montmorillonite (Mt) and the smectite component of a 70-30 illite-smectite mixed layer clay (I-S) and poorer crystallinity overall as a result of exfoliation of tactoids. Peptide adsorption is concentration-dependent, however, surface adsorption appears to mediate interlayer adsorption in Mt reaching a maximum of 16% of the mass of the organoclay complex, indicating that at a critical concentration, peptide intercalation will supersede surface adsorption resulting in a more stable attachment. In I-S the degree of surface adsorption and intercalation is proportional to concentration, however, surface adsorption is not a priming mechanism for interlayer adsorption. Thermogravimetric analysis of the organoclay complexes determined by TGA coupled to GC-MS indicate that the most prominent product species measured was 1-(1-Trimethylsiloxyethenyl)-3-trimethylsiloxy-benzene, likely from tryptophan monomer decomposition. The compound was detected over a broad temperature range, greater than 300 oC, during pyrolysis and suggests a carbon-silicon covalent bond formed between the peptide and tetrahedral layers in the clay. An additional silicon-bearing VOC detected at lower pyrolysis temperature by GC was N,N-Diethyl-1-(trimethylsilyl)-9,10-didehydroergoline-8-carboxamide, likely derived from a lysine-bearing peptide derivative. We hypothesize that hydrophobic (non-ionic) peptides react with silanol

  13. SURFACTANTS IN LUBRICATION

    Science.gov (United States)

    Surfactants are one of the most widely applied materials by consumers and industry. The application areas for surfactants span from everyday mundane tasks such as cleaning, to highly complex processes involving the formulation of pharmaceuticals, foods, pesticides, lubricants, etc. Even though sur...

  14. Dynamic covalent surfactants

    NARCIS (Netherlands)

    Minkenberg, C.B.

    2012-01-01

    In this thesis the development of surfactant aggregates with fast exchange dynamics between the aggregated and non-aggregated state is described. Dynamic surfactant exchange plays an important role in natural systems, for instance in cell signaling, cell division, and uptake and release of cargo. Re

  15. Dehydration transformation in Ca-montmorillonite

    Indian Academy of Sciences (India)

    P Bala; B K Samantaray; S K Srivastava

    2000-02-01

    The present work deals with the dehydration transformation of Ca-montmorillonite in the temperature range 30°–500°C. Thermal, infrared (IR), and X-ray diffraction (XRD) analyses were used to describe the thermal transformation. The microstructural and layer disorder parameters like crystallite size, r.m.s. strain ($\\langle e^2\\rangle^{1/2}$), variation of interlayer spacing (), and proportion of planes which were affected by the defect (), have all been calculated from the (001) basal reflection using the method of variance and Fourier line shape analysis. These investigations revealed that sample underwent transformation from hydrated phase to dehydrated phase at 200°C, and as a consequence, its basal spacing collapsed from 16.02 Å (30°C) to around 10 Å (200°C). This transformation occurred through a wide range of temperature, i.e. within the range 120°–200°C. The crystallite size was maximum at room temperature (30°C), however, the size decreased with increasing temperature in the hydrated phase, whereas the size increased with increasing temperature for the dehydrated phase. The , and $\\langle e^2\\rangle^{1/2}$ of the hydrated and the dehydrated phase increased and decreased, respectively with increase of heating temperature.

  16. Peptide Formation Mechanism on Montmorillonite Under Thermal Conditions

    Science.gov (United States)

    Fuchida, Shigeshi; Masuda, Harue; Shinoda, Keiji

    2014-02-01

    The oligomerization of amino acids is an essential process in the chemical evolution of proteins, which are precursors to life on Earth. Although some researchers have observed peptide formation on clay mineral surfaces, the mechanism of peptide bond formation on the clay mineral surface has not been clarified. In this study, the thermal behavior of glycine (Gly) adsorbed on montmorillonite was observed during heating experiments conducted at 150 °C for 336 h under dry, wet, and dry-wet conditions to clarify the mechanism. Approximately 13.9 % of the Gly monomers became peptides on montmorillonite under dry conditions, with diketopiperazine (cyclic dimer) being the main product. On the other hand, peptides were not synthesized in the absence of montmorillonite. Results of IR analysis showed that the Gly monomer was mainly adsorbed via hydrogen bonding between the positively charged amino groups and negatively charged surface sites (i.e., Lewis base sites) on the montmorillonite surface, indicating that the Lewis base site acts as a catalyst for peptide formation. In contrast, peptides were not detected on montmorillonite heated under wet conditions, since excess water shifted the equilibrium towards hydrolysis of the peptides. The presence of water is likely to control thermodynamic peptide production, and clay minerals, especially those with electrophilic defect sites, seem to act as a kinetic catalyst for the peptide formation reaction.

  17. Hydrogen intercalation under graphene on Ir(111)

    Science.gov (United States)

    Grånäs, Elin; Gerber, Timm; Schröder, Ulrike A.; Schulte, Karina; Andersen, Jesper N.; Michely, Thomas; Knudsen, Jan

    2016-09-01

    Using high resolution X-ray photoelectron spectroscopy and scanning tunneling microscopy we study the intercalation of hydrogen under graphene/Ir(111). The hydrogen intercalated graphene is characterized by a component in C 1s that is shifted -0.10 to -0.18 eV with respect to pristine graphene and a component in Ir 4f at 60.54 eV. The position of this Ir 4f component is identical to that of the Ir(111) surface layer with hydrogen atoms adsorbed, indicating that the atomic hydrogen adsorption site on bare Ir(111) and beneath graphene is the same. Based on co-existence of fully- and non-intercalated graphene, and the inability to intercalate a closed graphene film covering the entire Ir(111) surface, we conclude that hydrogen dissociatively adsorbs at bare Ir(111) patches, and subsequently diffuses rapidly under graphene. A likely entry point for the intercalating hydrogen atoms is identified to be where graphene crosses an underlying Ir(111) step.

  18. Formation of RNA oligomers on montmorillonite: site of catalysis

    Science.gov (United States)

    Ertem, G.; Ferris, J. P.

    1998-01-01

    Certain montmorillonites catalyze the self condensation of the 5'-phosphorimidazolide of nucleosides in pH 8 aqueous electrolyte solutions at ambient temperatures leading to formation of RNA oligomers. In order to establish the nature of the sites on montmorillonite responsible for this catalytic activity, oligomerization reactions were run with montmorillonites which had been selectively modified (I) at the edges by (a) fluoride treatment, (b) silylation, (c) metaphosphate treatment of the anion exchange sites (II) in the interlayer by (a) saturation with quaternary alkylammonium ions of increasing size, (b) aluminum polyoxo cations. High pressure liquid chromatography, HPLC, analysis of condensation products for their chain lengths and yields indicated that modification at the edges did not affect the catalytic activity to a significant extent, while blocking the interlayer strongly inhibited product formation.

  19. Genotoxicity of unmodified and organo-modified montmorillonite

    DEFF Research Database (Denmark)

    Sharma, Anoop Kumar; Schmidt, Bjørn; Frandsen, Henrik Lauritz;

    2010-01-01

    The natural clay mineral montmorillonite (Cloisite (R) Na+) and an organo-modified montmorillonite (Cloisite (R) 30B) were investigated for genotoxic potential as crude suspensions and as suspensions filtrated through a 0.2-mu m pore-size filter to remove particles above the nanometre range...... absent in the filtered samples, which was independently confirmed by dynamic light-scattering measurements. Detection and identification of free quaternary ammonium modifier in the filtered sample was carried out by HPLC-Q-TOF/MS and revealed a total concentration of a mixture of quaternary ammonium...... analogues of 1.57 mu g/ml. These findings suggest that the genotoxicity of organo-modified montmorillonite was caused by the organo-modifier. The detected organo-modifier mixture was synthesized and comet-assay results showed that the genotoxic potency of this synthesized organo-modifier was in the same...

  20. Study of relaxation times of nanocomposites of starch/montmorillonite employing low field NMR; Estudo dos tempos de relaxacao de nanocompositos de amido e argila montmorilonita por RMN de baixo campo

    Energy Technology Data Exchange (ETDEWEB)

    Brito, Luciana M.; Tavares, Maria Ines B. [Universidade Federal do Rio de Janeiro, Instituto de Macromoleculas Professora Eloisa Mano, Rio de Janeiro, RJ (Brazil)

    2011-07-01

    Due to its various applications and features, especially in therapies for controlled release of pharmaceuticals, polymers are among the most widely used excipients in pharmaceutical technology. One of the most promising nanocomposites is formed from organic polymer and inorganic clay minerals. Nanocomposites of starch/montmorillonite were prepared employing solution intercalation and characterized by proton spin-lattice relaxation time, through NMR relaxometry. The characterization of nanocomposites was done by X-ray diffraction and by nuclear magnetic resonance. The results showed that nanostructured films were obtained by intercalation from solution. Furthermore, the use of low field NMR, T1H, provided more precise information about the movement of materials, being complementary to the results obtained by X-ray diffraction. (author)

  1. Feasibility of intercalated graphite railgun armatures

    Science.gov (United States)

    Gaier, James R.; Gooden, Clarence E.; Yashan, Doreen; Naud, Steven

    1990-01-01

    Graphite intercalation compounds may provide an excellent material for the fabrication of electro-magnetic railgun armatures. As a pulse of power is fed into the armature the intercalate could be excited into the plasma state around the edges of the armature, while the bulk of the current would be carried through the graphite block. Such an armature would have the desirable characteristics of both diffuse plasma armatures and bulk conduction armatures. In addition, the highly anisotropic nature of these materials could enable the electrical and thermal conductivity to be tailored to meet the specific requirements of electromagnetic railgun armatures. Preliminary investigations were performed in an attempt to determine the feasibility of using graphite intercalation compounds as railgun armatures. Issues of fabrication, resistivity, stability, and electrical current spreading are addressed for the case of highly oriented pyrolytic graphite.

  2. Surfactants in the environment.

    Science.gov (United States)

    Ivanković, Tomislav; Hrenović, Jasna

    2010-03-01

    Surfactants are a diverse group of chemicals that are best known for their wide use in detergents and other cleaning products. After use, residual surfactants are discharged into sewage systems or directly into surface waters, and most of them end up dispersed in different environmental compartments such as soil, water or sediment. The toxic effects of surfactants on various aquatic organisms are well known. In general, surfactants are present in the environment at levels below toxicity and in Croatia below the national limit. Most surfactants are readily biodegradable and their amount is greatly reduced with secondary treatment in wastewater treatment plants. The highest concern is the release of untreated wastewater or wastewater that has undergone primary treatment alone. The discharge of wastewater polluted with massive quantities of surfactants could have serious effects on the ecosystem. Future studies of surfactant toxicities and biodegradation are necessary to withdraw highly toxic and non-biodegradable compounds from commercial use and replace them with more environmentally friendly ones.

  3. Pulmonary surfactant and lung transplantation

    NARCIS (Netherlands)

    Erasmus, Michiel Elardus

    1997-01-01

    Pulmonary surfactant lowers the surface tension at the air-water interface inside the alveolus. This is achieved by adsorption of surfactant phospholipids at the air-water interface, a process controlled by surfactant-associated proteins, such as SP-A. In this way, surfactant prevents collapse of th

  4. Effect of montmorillonite on kinetics of polyurethane preparation reaction

    Institute of Scientific and Technical Information of China (English)

    You Cao; Yu Jiang; Shu Lu Zhao; Xiao Jun Cai; Mei Long Hu; Bing Liao

    2008-01-01

    The prepolymerization and curing reaction kinetics of polyurethane/montmorillonite have been studied with end group analysisand FTIR respectively. It was found that the prepolymerization and curing reaction followed the 2nd-order kinetics. But theactivation energy of prepolymerization increased from 42.7 k J/mol to 56.5 k J/mol after the montmorillonite was added in thereaction system, and activation energy of curing reaction decreased from 64.4 kJ/mol to 17.5 k J/mol.

  5. Metathesis depolymerizable surfactants

    Science.gov (United States)

    Jamison, Gregory M.; Wheeler, David R.; Loy, Douglas A.; Simmons, Blake A.; Long, Timothy M.; McElhanon, James R.; Rahimian, Kamyar; Staiger, Chad L.

    2008-04-15

    A class of surfactant molecules whose structure includes regularly spaced unsaturation in the tail group and thus, can be readily decomposed by ring-closing metathesis, and particularly by the action of a transition metal catalyst, to form small molecule products. These small molecules are designed to have increased volatility and/or enhanced solubility as compared to the original surfactant molecule and are thus easily removed by solvent extraction or vacuum extraction at low temperature. By producing easily removable decomposition products, the surfactant molecules become particularly desirable as template structures for preparing meso- and microstructural materials with tailored properties.

  6. Contribution of sodium dodecyl sulphate and sodium lauric acid in the one-pot synthesis of intercalated ZnAl-layered double hydroxides

    Indian Academy of Sciences (India)

    Fengzhu Lv; Zilin Meng; Penggang Li; Yihe Zhang; Guocheng Lv; Qian Zhang; Zhilei Zhang

    2015-08-01

    Anion surfactants, sodium dodecyl sulphate (SDS) and sodium lauric acid (SLA), with almost the same chain length but different anion groups were used together as intercalates to prepare intercalated ZnAl–layered double hydroxides (ZnAl–LDHs). Their composition, structure and morphology were characterized by Fourier transform infrared, X-ray fluorescence, thermogravimetric and X-ray diffraction (XRD). The results indicated SDS intended to maintain the lamellae structure of LDHs, but SLA was more likely to expand the basal spacings of LDHs in the present system. The arrangement of the surfactants in the interlayer of ZnAl–LDHs was also simulated by Materials Studio. The basal spacings of the LDHs calculated based on simulated structure consisted with that from XRD.

  7. The investigation of electrokinetic behaviour of micro-particles produced by CTA{sup +} ions and Na-montmorillonite

    Energy Technology Data Exchange (ETDEWEB)

    Gürses, Ahmet, E-mail: ahmetgu@yahoo.com [Department of Chemistry Education, Ataturk University, 25240 Erzurum (Turkey); Güneş, Kübra; Mindivan, Ferda [Department of Chemistry Education, Ataturk University, 25240 Erzurum (Turkey); Korucu, Mehtap Ejder [Department of Chemistry, Kafkas University, 36100 Kars (Turkey); Açıkyıldız, Metin [Department of Chemistry, Kilis 7 Aralık University, 79000 Kilis (Turkey); Doğar, Çetin [Department of Science Education, Erzincan University, 24030 Erzincan (Turkey)

    2014-11-01

    Highlights: • The interactions between clay platelets and CTA{sup +} ions in aqueous dispersions of Na- montmorillonite (Na-MMT) was investigated by using electro-kinetic parameters and by considering XRD patterns and d-spacing values of the organoclay samples. • The d-spacing values and zeta potentials of the particles increased with increasing initial CTAB concentration in parallel with the electrical conductivity values. • A “stress region” was described by considering hydrophobic binding at certain solid/liquid ratios. • The calculated thermodynamic parameters such as Gibbs free energy, isosteric enthalpy, and isosteric entropy were revealed that the adsorption of CTAB onto Na-montmorillonite is spontaneous and exothermic. - Abstract: In this study, the interactions between clay platelets and CTA{sup +} ions in aqueous dispersions of Na-montmorillonite (Na-MMT) were examined in detail by using electro kinetic parameters such as electrical conductivity and zeta potential and by considering XRD patterns and d-spacing values of the organoclay samples as a function of both surfactant concentration (CTAB, cetyltrimethylammonium bromide) and clay amount. The amounts adsorbed and zeta potentials of the particles increased with an increase in the initial concentration of CTAB in parallel with the electrical conductivity values. The adsorption mechanisms which predominate at certain ranges of CTAB concentration were proposed and schematized by considering the d-spacing values calculated and the zeta potential values of particles. For the different solid/liquid ratios, the initial concentrations of CTAB, in which appeared significant increases in the d-spacing values were found as 200, 280 and 300 mg/L, respectively. The d-spacing values which correspond to these concentrations are, respectively 1.82, 1.82 and 1.68 nm. It is remarkable that at first three solid/liquid ratios, a “stress region” to be related with hydrophobic binding appeared. Thermodynamic

  8. True performance metrics in beyond-intercalation batteries

    Science.gov (United States)

    Freunberger, Stefan A.

    2017-07-01

    Beyond-intercalation batteries promise a step-change in energy storage compared to intercalation-based lithium-ion and sodium-ion batteries. However, only performance metrics that include all cell components and operation parameters can tell whether a true advance over intercalation batteries has been achieved.

  9. Phosphine oxide surfactants revisited.

    Science.gov (United States)

    Stubenrauch, Cosima; Preisig, Natalie; Laughlin, Robert G

    2016-04-01

    This review summarizes everything we currently know about the nonionic surfactants alkyl dimethyl (C(n)DMPO) and alkyl diethyl (C(n)DEPO) phosphine oxide (PO surfactants). The review starts with the synthesis and the general properties (Section 2) of these compounds and continues with their interfacial properties (Section 3) such as surface tension, surface rheology, interfacial tension and adsorption at solid surfaces. We discuss studies on thin liquid films and foams stabilized by PO surfactants (Section 4) as well as studies on their self-assembly into lyotropic liquid crystals and microemulsions, respectively (Section 5). We aim at encouraging colleagues from both academia and industry to take on board PO surfactants whenever possible and feasible because of their broad variety of excellent properties.

  10. Bromine intercalated graphite for lightweight composite conductors

    KAUST Repository

    Amassian, Aram

    2017-07-20

    A method of fabricating a bromine-graphite/metal composite includes intercalating bromine within layers of graphite via liquid-phase bromination to create brominated-graphite and consolidating the brominated-graphite with a metal nanopowder via a mechanical pressing operation to generate a bromine-graphite/metal composite material.

  11. Chemical composition and surface charge properties of montmorillonite

    Institute of Scientific and Technical Information of China (English)

    LIU Xiao-wen; HU Min; HU Yue-hua

    2008-01-01

    The effects of the cell parameter and chemical composition on the surface charge properties of five kinds of different colour montmorillonites were studied. The results indicate that the surface isoelectric point(IEP) of the montmorillonite shows positive correlation with the mass fractions of Fe2O3 and K20, but it has little relation to the mass fractions of other chemical compositions. At around pH=6.8, the surface zeta potential of the montmorillonite shows the negative relationship with the mass fractions of Fe2O3 and MgO, but it does not linearly correlate to the mass fractions of other chemical compositions. Cell parameter(b0) of the montmofillonite expresses negative linear relationship with mass fractions of K2O and Na2O, so does c0sinβ with mass fractions of SiO2 and Fe2O3. And there is no specific relationship between bo and IEP of different montmori Uonites, but there is positive correlation between c0sinβ and IEP of different montmorillonite samples.

  12. Characterization and Identification of Bituminous Materials Modified with Montmorillonite Nanoclay

    NARCIS (Netherlands)

    Liu, G.

    2011-01-01

    Montmorillonite (Mt) nanoclay is a layered silicate mineral with a 2:1-type layer structure, two tetrahedrals sandwiching one octahedral. In recent decades, it is successfully introduced into polymer systems to form polymer-clay nanocomposites (PCN) in which the silicate layers of the Mt are randoml

  13. Polynaphthoxazines-Montmorillonite Nanocomposites:Synthesis and Characterization

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    Polynaphthoxazines-clay nanocomposites were prepared from 1, 5-dihydroxynaphthalene, aniline, formaldehyde and different proportion montmorillonite(MMT) by in-situ reaction in ethanol. Dynamic TGA showed that nanocomposites have delayed decomposition temperatures when compared with pristine polynaphthoxazine indicating the enhancement in the thermal stability.

  14. Chitosan-Montmorillonite microspheres: A sustainable fertilizer delivery system.

    Science.gov (United States)

    dos Santos, Bruna Rodrigues; Bacalhau, Fabiana Britti; Pereira, Tamires dos Santos; Souza, Claudinei Fonseca; Faez, Roselena

    2015-08-20

    Controlled release fertilizers are efficient tools that increase the sustainability of agricultural practices. However, the biodegradability of the matrices and the determination of the release into soil still require some investigation. This paper describes the preparation of potassium-containing microspheres based on chitosan and montmorillonite clay and the in situ soil release. The chitosan-montmorillonite microspheres were prepared using a coagulation method and different proportions of montmorillonite. The structural, thermal and morphological properties as well the water swelling and fertilizer sorption capacity were evaluated. The best formulations were applied in soil, and the fertilizer release was monitored using time-domain reflectometry (TDR). Montmorillonite clay provides better sorption properties than the chitosan microspheres because of the rough and porous surface. Due to these properties, high levels of fertilizer were sorbed onto the material. ChMMT33-containing potassium shows two specific periods of fertilizer release: the first one lasted approximately three days and was assigned to the external fertilizer on the microspheres. The second was assigned to the internal fertilizer. TDR is an important and fast tool and was used to determine the fertilizer release and the ion movement in the soil.

  15. Adsorption and desorption properties for Congo red dye of carboxymethylcellulose/montmorillonite nanocomposites%羧甲基纤维素/蒙脱土纳米复合材料对刚果红染料的吸附及解吸性能

    Institute of Scientific and Technical Information of China (English)

    赵亚红; 薛振华; 王喜明; 王丽

    2012-01-01

    用X射线衍射、透射电镜和扫描电镜对羧甲基纤维素/蒙脱土纳米复合材料的结构进行表征.采用溶液插层复合法制备纳米复合材料,探讨不同羧甲基纤维素与蒙脱土质量比、反应时间和反应温度对纳米复合材料吸附刚果红染料吸附量的影响,并初步研究了纳米复合材料的解吸性能.亚微观观察表明:羧甲基纤维素通过破坏蒙脱土的晶体结构插层进入蒙脱土层间,形成插层-剥离型纳米复合材料;当羧甲基纤维素与蒙脱土质量比为1∶1,反应时间为6h,反应温度为60℃时,纳米复合材料对刚果红染料的吸附量最大,可达50.42 mg·g-1;当解吸试剂氢氧化钠浓度为0.01 mol·L-1时,超声波解吸50 min的纳米复合材料脱附率可达80.17%.%The structure of carboxymethylcellulose/montmorillonite (CMC/MMT) nanocomposites was characterized by X-ray diffraction ( XRD) , transmission electron microscope (TEM) and scanning electron microscope (SEM). The nanocomposites were prepared with a solution intercalation technique and the effects of mass ratio of carboxymethylcellulose to montmorillonite, reaction time and reaction temperature on adsorption capacity were investigated. The desorption properties were also investigated. Microscopic observation showed that carboxymethylcellulose intercalated into montmorillonite interlayer via destroying the crystalline structure of montmorillonite, and intercalated-exfoliated structure was formed in carboxymethylcellulose/montmorillonite nanocomposites. The maximum adsorption capacity of the nanocomposite for Congo red dye was as high as 50. 42 mg· g-1 using the mass ratio of carboxymethylcellulose to montmorillonite of 1 : 1 after being treated at 60℃ for 6 h. The desorption efficiency of the nanocomposite was 80. 17% using desorption agent of 0. 01 mol · L-1 NaOH after being treated by ultrasonic wave for 50 min.

  16. Preparation of polypropylene/montmorillonite nanocomposites by intercalative polymerization: Effect of in situ polymer matrix functionalization on the stability of the nanocomposite structure

    Institute of Scientific and Technical Information of China (English)

    YANG KeFang; HUANG YingJuan; DONG JinYong

    2007-01-01

    The copolymerization of propylene and 5-hexenyl-9-borabicyclo[3.3.1]nonane (5-hexenyl-9-BBN) has been conducted with an MgCl2/TiCl4 catalyst intercalated in an organically modified montmorillonite (OMMT) with triethylaluminum (AlEt3) cocatalyst and diphenyldimethoxysilane (DDS) external donor. This polymerization process simultaneously results in both the exfoliation of MMT layers to realize the preparation of polypropylene (PP)/MMT nanocomposites and the implantation of reactive borane groups in the formed PP matrix. The polymer-borne borane groups have been able to undergo an efficient hydrolysis process under very mild reaction conditions (40℃, 3 h, in THF), introducing hydroxy groups into PP without sacrificing the polymerization-formed nanocomposite structure (the exfoliation of MMT). The resultant hydroxyl-functionalized PP/MMT nanocomposites exhibit enhanced structural stability against processing compared with those based on unfunctionalized PP matrix.

  17. A novel method for fabricating hybrid biobased nanocomposites film with stable fluorescence containing CdTe quantum dots and montmorillonite-chitosan nanosheets.

    Science.gov (United States)

    Guo, Yawen; Ge, Xuesong; Guan, Jing; Wu, Lin; Zhao, Fuhua; Li, Hui; Mu, Xindong; Jiang, Yijun; Chen, Aibing

    2016-07-10

    A method was presented for fabricating the fluorescent nanocomposites containing CdTe quantum dots (QDs) and montmorillonite (MMT)-chitosan (CS). MMT-CS/CdTe QDs nanocomposites were prepared via a simple, versatile and robust approach combination of covalent and electrostatic assembly methods (Scheme 1). The negatively charged MMT was initially modified with positively charged CS through electrostatic assembly, followed by incorporation of CdTe-QDs into the MMT-CS nanosheets by covalent connections between the amino groups of CS and the carboxylic acid groups of thioglycollic acid (TGA). The X-ray diffraction (XRD), High resolution transmission electron microscopy (HRTEM), scanning electron microscopy (SEM) and the FTIR were used to prove the QDs have intercalated into the MMT-CS matrix. The fluorescence emission spectra showed that the MMT-CS/CdTe QDs nanocomposites had the best fluorescence intensity compared with the bare CdTe QDs and CS-QDs.

  18. Electrochemical intercalation of potassium into graphite in KF melt

    Energy Technology Data Exchange (ETDEWEB)

    Liu Dongren [College of Chemistry and Chemical Engineering, Central South University, South Lushan Road, Changsha 410083, Hunan (China); Department of Chemical and Environmental engineering, Jiaozuo University, JiaoZuo 454003, Henan (China); Yang Zhanhong, E-mail: zhyang@mail.csu.edu.c [College of Chemistry and Chemical Engineering, Central South University, South Lushan Road, Changsha 410083, Hunan (China); Li Wangxing; Qiu Shilin; Luo Yingtao [Zhengzhou Research Institute of Chalco, Zhengzhou 450041, Henan (China)

    2010-01-01

    Electrochemical intercalation of potassium into graphite in molten potassium fluoride at 1163 K was investigated by means of cyclic voltammetry, galvanostatic electrolysis and open-circuit potential measurements. It was found that potassium intercalated into graphite solely between graphite layers. In addition, the intercalation compound formed in graphite bulk in molten KF was quite unstable and decomposed very fast. X-ray diffraction measurements indicate that a very dilute potassium-graphite intercalation compound was formed in graphite matrix in the fluoride melt. Analysis with scanning electron microscope and transmission electron microscope shows that graphite was exfoliated to sheets and tubes due to lattice expansion caused by intercalation of potassium in molten KF.

  19. Cotransport of bismerthiazol and montmorillonite colloids in saturated porous media.

    Science.gov (United States)

    Shen, Chongyang; Wang, Hong; Lazouskaya, Volha; Du, Yichun; Lu, Weilan; Wu, Junxue; Zhang, Hongyan; Huang, Yuanfang

    2015-01-01

    While bismerthiazol [N,N'-methylene-bis-(2-amino-5-mercapto-1,3,4-thiadiazole)] is one of the most widely used bactericides, the transport of bismerthiazol in subsurface environments is unclear to date. Moreover, natural colloids are ubiquitous in the subsurface environments. The cotransport of bismerthiazol and natural colloids has not been investigated. This study conducted laboratory column experiments to examine the transport of bismerthiazol in saturated sand porous media both in the absence and presence of montmorillonite colloids. Results show that a fraction of bismerthiazol was retained in sand and the retention was higher at pH7 than at pH 4 and 10. The retention did not change with ionic strength. The retention was attributed to the complex of bismerthiazol with metals/metal oxides on sand surfaces through ligand exchange. The transport of bismerthiazol was enhanced with montmorillonite colloids copresent in the solutions and, concurrently, the transport of montmorillonite colloids was facilitated by the bismerthiazol. The transport of montmorillonite colloids was enhanced likely because the bismerthiazol and the colloids competed for the attachment/adsorption sites on collector surfaces and the presence of bismerthiazol changed the Derjaguin-Landau-Verwey-Overbeek (DLVO) interaction energies between colloids and collectors. The transport of bismerthiazol was inhibited if montmorillonite colloids were pre-deposited in sand because bismerthiazol could adsorb onto the colloid surfaces. The adsorbed bismerthiazol could be co-remobilized with the colloids from primary minima by decreasing ionic strength. Whereas colloid-facilitated transport of pesticides has been emphasized, our study implies that transport of colloids could also be facilitated by the presence of pesticides. Copyright © 2015 Elsevier B.V. All rights reserved.

  20. The effects of surfactants on penetration across the skin*.

    Science.gov (United States)

    Walters, K A; Bialik, W; Brain, K R

    1993-12-01

    Synopsis Many of the properties of surfactants can be related to their ability to concentrate at phase interfaces, leading to a reduction in interracial tension. In biological systems the effects of surfactants are complex, particularly their effect on cell and other membranes, and this can lead to alterations in permeability characteristics. This is of particular relevance when considering the stratum corneum which has long been recognized as the major barrier to skin permeation. The magnitude of skin barrier function alteration is dependent on surfactant structure, both the hydrophobic alkyl chain and the hydropnilic ethylene oxide chain demonstrating some structure-activity behaviour. In many biological systems, including skin, surfactants with a similar hydrophilic group will show maximum membrane activity if they possess a decyl or dodecyl alkyl chain. It is difficult to rationalise this phenomenon, given that such solution properties as partition coefficients and CMCs do not show maxima or minima at these chain lengths. It may be that the physical parameters and molecular dimensions of the decyl/dodecyl chain provide the optimal ability to intercalate with the lipid bilayer structure. There is little doubt that once the surfactant has intercalated with the lipid bilayers in the lamellar liquid crystals of the stratum corneum, fluidity in the hydrophobic regions is increased. Effectively, this leads to a looser, more permeable structure. The significance of data obtained using commercially available surfactants, however, can be questioned on the grounds of purity. The purpose of this review is to describe some of the methods used to evaluate the effects of surfactants on the skin barrier and to discuss recent attempts to predict surfactant action on the skin using various biological and physical techniques. Résumé La plupart des propriétés des surfactants dépend de leur facilitéà se concentrer aux interfaces, menant ainsi à la réduction de la tension

  1. Effect of knots on binding of intercalators to DNA

    Science.gov (United States)

    Medalion, Shlomi; Rabin, Yitzhak

    2014-05-01

    We study the effect of knots in circular dsDNA molecules on the binding of intercalating ligands. Using Monte Carlo simulations we show that depending on their handedness, the presence of knots can either suppress or enhance intercalation in supercoiled DNA. When the occupancy of intercalators on DNA is low, the effect of knots on intercalation can be captured by introducing a shift in the mean writhe of the chain that accounts for the writhe of the corresponding ideal knot. In the limit of high intercalator occupancy, the writhe distribution of different knots is strongly affected by excluded volume effects and therefore by salt concentration. Based on the finding that different knots yield well-separated probability distributions of bound intercalators, we propose a new experimental approach to determine DNA topology by monitoring the intensity of fluorescence emitted by dye molecules intercalated into knotted DNA molecules.

  2. Adsorption of PolyCarboxylate Poly(ethylene glycol) (PCP) esters on Montmorillonite (Mmt): effect of exchangeable cations (Na+, Mg2+ and Ca2+) and PCP molecular structure.

    Science.gov (United States)

    Ait-Akbour, Rachid; Boustingorry, Pascal; Leroux, Fabrice; Leising, Frédéric; Taviot-Guého, Christine

    2015-01-01

    This study deals with the adsorption of PolyCarboxylate Poly(ethylene glycol) esters (PCP) superplasticizers on Na-, Mg- and Ca-saturated Montmorillonite (Mmt) clays. The interactions have been examined through different experimental methods: adsorption isotherms, zeta potential measurements and sedimentation experiments. It was found that PCP adsorption depends both on the architecture of PCP molecules and the nature of cation located on the interlayer exchange sites of the Montmorillonite. Whatever the PCP, a larger amount was adsorbed on Na-Mont than on Mg-Mont or Ca-Mont. This indicates the occurrence of two adsorption mechanisms: (i) a superficial adsorption via electrostatic interactions between the carboxylate groups of PCP and positively charged sites on clay surfaces, (ii) intercalation of ether units of the PCP grafts in the interlayer space by displacement of water molecules coordinated to the exchangeable cations. Furthermore, despite the weak negative values of the zeta potential, the addition of PCP promotes the stability of the suspensions which is attributed to steric repulsion acting between particles. Copyright © 2014 Elsevier Inc. All rights reserved.

  3. Activity of Laccase Immobilized on TiO2-Montmorillonite Complexes

    Directory of Open Access Journals (Sweden)

    Fenglin Huang

    2013-06-01

    Full Text Available The TiO2-montmorillonite (TiO2-MMT complex was prepared by blending TiO2 sol and MMT with certain ratio, and its properties as an enzyme immobilization support were investigated. The pristine MMT and TiO2-MMT calcined at 800 °C (TiO2-MMT800 were used for comparison to better understand the immobilization mechanism. The structures of the pristine MMT, TiO2-MMT, and TiO2-MMT800 were examined by HR-TEM, XRD and BET. SEM was employed to study different morphologies before and after laccase immobilization. Activity and kinetic parameters of the immobilized laccase were also determined. It was found that the TiO2 nanoparticles were successfully introduced into the MMT layer structure, and this intercalation enlarged the “d value” of two adjacent MMT layers and increased the surface area, while the calcination process led to a complete collapse of the MMT layers. SEM results showed that the clays were well coated with adsorbed enzymes. The study of laccase activity revealed that the optimum pH and temperature were pH = 3 and 60 °C, respectively. In addition, the storage stability for the immobilized laccase was satisfactory. The kinetic properties indicated that laccase immobilized on TiO2-MMT complexes had a good affinity to the substrate. It has been proved that TiO2-MMT complex is a good candidate for enzyme immobilization.

  4. Synthesis and characterization of TiO2 pillared montmorillonites: application for methylene blue degradation.

    Science.gov (United States)

    Chen, Daimei; Du, Gaoxiang; Zhu, Qian; Zhou, Fengsan

    2013-11-01

    TiO2 pillared clay composites were prepared by modifying of montmorillonite (Mt) with cetyl-trimethyammoniumbromide (CTAB) and then using an acidic solution of hydrolyzed Ti alkoxide to intercalate into the interlayer space of the organic modified Mt. The as-prepared materials were characterized by XRD, FTIR, TEM, SEM TG-DTA, specific surface area and porosity measurements. The composites had a porous delaminated structure with pillared fragments and well dispersed TiO2 nanoparticles. Introduction of CTAB into the synthetic system accelerated the hydrolysis and condensation of the Ti source, which promoted TiO2 formation. In addition, the CTAB also significantly increased the porosity and surface area of the composites. A number of anatase particles, with crystal sizes of 5-10 nm, were homogenously distributed on the surface of the Mt as the result of the templating role of CTAB. The resultant TiO2 pillared Mt exhibited good thermal stability as indicated by its surface area after calcination at 800°C. No phase transformations from anatase to rutile were observed even under calcination at 900°C. The grain size of the anatase in prepared sample increased from 2.67 nm to 13.42 nm as the calcination temperature increased from 300°C to 900°C. The photocatalytic performance of these new porous materials was evaluated by using methylene blue degradation. The composite exhibited better photocatalytic property than P 25. The maximum removal efficiency of this composite was up to 99% within 60 min.

  5. Surfactant-Amino Acid and Surfactant-Surfactant Interactions in Aqueous Medium: a Review.

    Science.gov (United States)

    Malik, Nisar Ahmad

    2015-08-01

    An overview of surfactant-amino acid interactions mainly in aqueous medium has been discussed. Main emphasis has been on the solution thermodynamics and solute-solvent interactions. Almost all available data on the topic has been presented in a lucid and simple way. Conventional surfactants have been discussed as amphiphiles forming micelles and amino acids as additives and their effect on the various physicochemical properties of these conventional surfactants. Surfactant-surfactant interactions in aqueous medium, various mixed surfactant models, are also highlighted to assess their interactions in aqueous medium. Finally, their applied part has been taken into consideration to interpret their possible uses.

  6. Comparative evaluation between montmorillonite clay/LLDPE and potassium hexaniobate/LLDPE nanocomposites: characterization of mechanical and transport properties; Avaliacao comparativa entre os nanocompositos de argila motmorilonita/LLDPE e com hexaniobato de potassio/LLDPE: caracterizacao das propriedades mecanicas e de transporte

    Energy Technology Data Exchange (ETDEWEB)

    Komatsu, Daniel; Otaguro, Harumi, E-mail: daniikom@yahoo.com.br [Universidade Federal de Sao Carlos (UFSCar), SP (Brazil). Departamento de Quimica; Ruvolo Filho, Adhemar C. [Universidade Federal de Sao Carlos (UFSCar), SP (Brazil). Departamento de Engenharia de Materiais

    2014-06-01

    Linear low density polyethylene-montmorillonite clay and linear low density polyethylene-organophilic niobate nanocomposites were obtained from dilution of masterbatch with 20% w/w of fillers in the LLDPE matrix by melt intercalation using a twin-screw extruder, obtaining nanocomposites with 1.5% up to 10.0% w/w of filler. In this study mechanical and water vapor and oxygen permeation tests were used to characterize the nanocomposites. In mechanical tests an increase of modulus values and decrease of toughness value by increasing concentration of montmorillonite clay were observed. The behavior of LLDPE-organophilic niobate nanocomposites was similar to LLDPE-montmorillonite clay nanocomposites but softer due to hexaniobate structure. The distribution of the organoclay is more homogeneous than organophilic niobate to concentrations below 10.0% filler using the SEM/FEG. It is possible to see a decrease in the permeability value with increasing concentration of montmorillonite clay for both gases used. In the LLDPE-organophilic niobate nanocomposites a decrease of permeability value occurs followed by an increase of permeability value for both gases used, with increasing concentration of organophilic niobate. Furthermore, it was observed that the polarity of the gas used is an important factor in the diffusion process through the nanocomposite. (author)

  7. THERMODINAMIC PARAMETERS ON THE SORPTION OF PHOSPHATE IONS BY MONTMORILLONITE

    Directory of Open Access Journals (Sweden)

    Ikhsan Jaslin

    2016-04-01

    Full Text Available The sorption of phosphate by montmorillonite at 10, 30, and 50 oC were investigated aiming to mainly determine thermodynamic parameters for the formation of surface complexes in the adsorption of phosphate ions by montmorillonite. Data were collected by adsorption edge experiments investigating the effect of pH, adsorption isotherms enabling the effect of sorbate concentration, and acid-base titration calculating protons released or taken up by adsorption process. Data analysis was carried out using surface complexation model to fit the data collected in this study using the parameters obtained from previous study, as well as to calculate the values of ΔH and ΔS. Previous study reported that phosphate ions formed two outer-sphere surface complexes with active sites of montmorillonite through hydrogen bonding. In the first complex,  [(XH0– H2L─]─, the phosphate was held to permanent-charge X─ sites on the tetrahedral siloxane faces, and the second complex, [[(SO─(SOH]– – [H2L]─] 2─ was formed through the interaction between the phosphate and variable charge surface hydroxyl groups at the edges of montmorillonite crystals and on the octahedral alumina faces. The values of ΔH for the first and second reactions are 39.756 and 3.765x10-7 kJ mol‒1 respectively. Since both reactions have positive enthalpy values, it can be concluded that the reactions are endothermic. Large energy for the first reaction is needed by X─  sites (permanent negatively charge sites of montmorillonite to be partially desolvated, on which K+ or other surface cations are replaced by H+ ions in the surface protonated process, and are then ready to interact phosphate ions in the solution. Small values of ΔH for the second reactions indicates that hydrogen bonds formed by phosphate and SOH sites in the second reaction are easily broken out, and the phosphate can easily desorbed from the surface. The values of ΔS for the first and second reactions are

  8. Structure-Property Relationships in Intercalated Graphite.

    Science.gov (United States)

    1982-10-01

    phonon dispersion relations) G. Timp, Graduate Student (electron microscopy, high field magneto- resistance, modeling) L. Salamanca -Riba, Graduate...transition, in agreement with Monte Carlo calculations based on 2-dimensional models. 3.3.3 Fermi Surface Measurements To determine the electronic...Intercalation Compounds", M. Shayegan, M. Elahy, L. Salamanca -Riba, J. Heremans, C. Nicolini, and G. Dresselhaus, Bulletin APS 27, 342 (1982). 45

  9. Sol-gel hybrid films based on organosilane and montmorillonite for corrosion inhibition of AA2024.

    Science.gov (United States)

    Dalmoro, V; dos Santos, J H Z; Armelin, E; Alemán, C; Azambuja, D S

    2014-07-15

    The present work reports the production of films on AA2024-T3 composed of vinyltrimethoxysilane (VTMS)/tetraethylorthosilicate (TEOS) with incorporation of montmorillonite (sodium montmorillonite and montmorillonite modified with quaternary ammonium salt, abbreviated Na and 30B, respectively), generated by the sol-gel process. According to FT-IR analyses the incorporation of montmorillonite does not affect silica network. Electrochemical characterization was performed by electrochemical impedance spectroscopy measurement in 0.05 mol L(-1) NaCl solution. Results indicate that montmorillonite incorporation improves the corrosion protection compared to the non-modified system. Scanning electron microscopy micrographs reveal that high concentrations of montmorillonite provide agglomerations on the metallic surface, which is in detriment of the anticorrosive performance. The VTMS/TEOS/30B films with the lowest concentration (22 mg L(-1)) of embedded clay provide the highest corrosion protection.

  10. Core level shifts of intercalated graphene

    Science.gov (United States)

    Schröder, Ulrike A.; Petrović, Marin; Gerber, Timm; Martínez-Galera, Antonio J.; Grånäs, Elin; Arman, Mohammad A.; Herbig, Charlotte; Schnadt, Joachim; Kralj, Marko; Knudsen, Jan; Michely, Thomas

    2017-03-01

    Through intercalation of metals and gases the Dirac cone of graphene on Ir(111) can be shifted with respect to the Fermi level without becoming destroyed by strong hybridization. Here, we use x-ray photoelectron spectroscopy to measure the C 1s core level shift (CLS) of graphene in contact with a number of structurally well-defined intercalation layers (O, H, Eu, and Cs). By analysis of our own and additional literature data for decoupled graphene, the C 1s CLS is found to be a non-monotonic function of the doping level. For small doping levels the shifts are well described by a rigid band model. However, at larger doping levels, a second effect comes into play which is proportional to the transferred charge and counteracts the rigid band shift. Moreover, not only the position, but also the C 1s peak shape displays a unique evolution as a function of doping level. Our conclusions are supported by intercalation experiments with Li, with which, due to the absence of phase separation, the doping level of graphene can be continuously tuned.

  11. Structure and characterization of Chinese fir (Cunninghamia lanceolata) wood/MMT intercalation nanocomposite (WMNC)

    Institute of Scientific and Technical Information of China (English)

    Wenhua Lü; Guangjie ZHAO

    2008-01-01

    With water-soluble phenol-formaldehyde resin as an intermediate,Chinese fir (Cunninghamia lanceolata) wood/montmorillonite nanocomposite (WMNC) was prepared through vacuum impregnation and character-ized with XRD, SEM, FTIR and TG-DTA analyses. The XRD analysis indicated that the wood crystallinity of WMNC decreased, the MMT exfoliated and some nano silicate layers entered into the non-crystallized micro-fibrillar region of the wood cell wall. Wood structure is anisotropic and its impregnation is anisotropic. Due to the nonuniformity of the MMT organic modification, PF intercalation and wood impregnation, the MMT config-uration and distribution in wood were diverse. The SEM graphs of WMNC showed that some silicate grains were blocked in the wood cell lumen,some silicate layers adhered to the inner surface of the wood cell wall, and some exfoliated MMT layers even penetrated the wood cell wall. The obtained hydroxyl of WMNC increased and its ether linking decreased. It was considered that MMT and wood interacted not only with hydroxyl bonds,but also involved some chemical linking.Compared with untreated wood and the PF-impreg, the pyrolysis process of WMNC changed; its starting decomposing temperature decreased and its pyrolysis weight loss at high temperatures greatly decreased. The WMNC indicated certain nanoeffects of the composition of the inorganic MMT nanolamellae.

  12. Nanocomposites of PP and bentonite clay modified with different surfactants; Nanocompositos de PP e bentonita organofilizada com diferentes tensoativos

    Energy Technology Data Exchange (ETDEWEB)

    Rodrigues, Andre W.B.; Agrawal, Pankaj; Araujo, Edcleide M.; Melo, Tomas J.A., E-mail: tomas@dema.ufcg.edu.b [Universidade Federal de Campina Grande (UFCG), PB (Brazil); Ueki, Marcelo M. [Servico Nacional de Aprendizagem Industrial (SENAI/CIMATEC), Salvador, BA (Brazil). Centro Integrado de Manufatura e Tecnologia

    2009-07-01

    The aim of this work was the development of nano composites of polypropylene (PP) and national bentonite clay modified with different surfactants. The results of X-Ray diffraction (XRD) and Fourier Transform Infrared Spectroscopy (FTIR) showed that the organophilization process was effective. The surfactants led to a significant increase in the basal spacing of Brasgel PA clay. XRD results of the mixture PP/Brasgel PA clay modified with Praepagem WB surfactant indicated that a nanocomposite with intercalated structure was formed. When the Brasgel PA clay was modified with Praepagem HY surfactant, DRX results indicated that a micro composite was formed. Screw speed, clay content and PP viscosity had no influence on the XRD pattern of the obtained materials. (author)

  13. Flame Retardant and Pyrolytic Behaviors of Polyamide 6/Montmorillonite Nanocomposite

    Institute of Scientific and Technical Information of China (English)

    LIU Zhi-guo; OU Yu-xiang; WU Jun-hao

    2005-01-01

    Na+-montmorillonite(Na+-MMT) was converted to organic montmorillonite(OMMT) using modifier which was synthesized at authors' laboratory. PA6/OMMT nanocomposite was prepared via in situ intercalative polymerization. The limiting oxygen index (LOI), UL 94V flame retardancy and thermal stability of PA6/OMMT using thermal gravity analysis (TGA) were measured. The Fourier transform infrared (FTIR) technique was used to analyze the pyrolytic residuum and the cone calorimeter (CONE) was applied to determine a number of combustion parameters which were closely related to fire safety, including heat release rate, mass loss rate, effective combustion heat, total heat release, specific extinction area and the time of ignition. In addition, the elemental composition of the surface pyrolytic residuum and the corresponding X-ray photoelectron spectroscopy (XPS) data were obtained, and the morphology of the residuum from CONE measurement was examined by scanning electron microscope (SEM).

  14. Adsorption of Congo Red onto Lignocellulose/Montmorillonite Nanocomposite

    Institute of Scientific and Technical Information of China (English)

    ZHAO Yahong; XUE Zhenhua; WANG Ximing; WANG Li; WANG Aiqin

    2012-01-01

    Lignocellulose/montmorillonite (LNC/MMT) nanocomposites were prepared and characterized by FTIR and XRD.The adsorption of congo red (CR) on LNC/MMT nanocomposite was studied in detail.The effects of contact temperature,pH value of the dye solutions,contact time and concentration of dye solutions on the adsorption capacities of lignocellulose (LNC),montmorillonite (MMT) and the nanocomposite were investigated.The adsorption kinetics and isotherms and adsorption thermodynamics of the nanocomposite for CR were also studied.The results show that the adsorption capacity of LNC/MMT nanocomosite is higher than that of LNC and MMT.All the adsorption processes fit very well with the pseudo-second-order and the Langmuir equation.From thermodynamic studies,it is seen that the adsorption is spontaneous and endothermic.

  15. Synthesis of a Biglucoside and Its Application as Montmorillonite Hydration Inhibitor

    Directory of Open Access Journals (Sweden)

    Xin-chun Zhang

    2014-01-01

    Full Text Available A biglucoside (BG was synthesized with glucose and epichlorohydrin as raw materials. The inhibition of BG against montmorillonite swelling was investigated by various methods including montmorillonite linear expansion test, mud ball immersing test, thermogravimetric analysis, and scanning electron microscopy. The results show that the BG has good inhibition ability to the hydration swelling and dispersion of montmorillonite. Under the same condition, the linear expansion ratio of montmorillonite in BG solution is much lower than that of MEG. The particle distribution measurement, thermogravimetric analysis, FT-IR, and scanning electron microscopy results all prove the efficient inhibition of BG.

  16. Proton conductive montmorillonite-Nafion composite membranes for direct ethanol fuel cells

    Science.gov (United States)

    Wu, Xiu-Wen; Wu, Nan; Shi, Chun-Qing; Zheng, Zhi-Yuan; Qi, Hong-Bin; Wang, Ya-Fang

    2016-12-01

    The preparation of Nafion membranes modified with montmorillonites is less studied, and most relative works mainly applied in direct methanol fuel cells, less in direct ethanol fuel cells. Organic/inorganic composite membranes are prepared with different montmorillonites (Ca-montmorillonite, Na-montmorillonite, K-montmorillonite, Mg-montmorillonite, and H-montmorillonite) and Nafion solution via casting method at 293 K in air, and with balance of their proton conductivity and ethanol permeability. The ethanol permeability and proton conductivity of the membranes are comparatively studied. The montmorillonites can well decrease the ethanol permeability of the membranes via inserted them in the membranes, while less decrease the proton conductivities of the membranes depending on the inserted amount and type of montmorillonites. The proton conductivities of the membranes are between 36.0 mS/cm and 38.5 mS/cm. The ethanol permeability of the membranes is between 0.69 × 10-6 cm2/s and 2.67 × 10-6 cm2/s.

  17. Sorption of aromatic hydrocarbons onto montmorillonite as affected by norfloxacin

    Energy Technology Data Exchange (ETDEWEB)

    Pei, Zhiguo, E-mail: peizg@rcees.ac.cn [State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, PO Box 2871, Beijing 100085 (China); Kong, Jingjing [School of Chemistry and Materials, Fujian Normal University, Fuzhou 350007 (China); Shan, Xiao-quan; Wen, Bei [State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, PO Box 2871, Beijing 100085 (China)

    2012-02-15

    Graphical abstract: {sup 1}H NMR spectrum provided direct evidence for {pi}-{pi} and cation-{pi} complexation between PAHs and Nor{sup +} by ring-current-induced upfield chemical shifts of the amino group and methylene group of Nor{sup +}. Highlights: Black-Right-Pointing-Pointer Nor decreases 1,3-DNB sorption, and increases NAPH, PHEN and PYR sorption on montmorillonite. Black-Right-Pointing-Pointer Nor{sup {+-}} increased PHEN and PYR sorption more pronounced than Nor{sup +} and Nor{sup -}. Black-Right-Pointing-Pointer The corresponding mechanisms were described by FTIR and {sup 1}H NMR. - Abstract: Effect of norfloxacin (Nor) on the sorption of 1,3-dinitrobenzene (1,3-DNB), and PAHs (naphthalene (NAPH), phenanthrene (PHEN) and pyrene (PYR)) to K{sup +}-montmorillonite was studied. Nor suppressed 1,3-DNB sorption due to their competition for the same sorption sites. 1,3-DNB was sorbed on K{sup +}-montmorillonite surface via cation-polar interaction and n-{pi} electron donor-acceptor interaction. Nor also was sorbed on these sites through cation exchange, cation bridging and/or surface complexation. Nor increased three PAHs sorption on montmorillonite and the enhanced magnitude was positively correlated with the {pi}-donor strength of three PAHs. The enhanced sorption of PAHs by Nor was primarily attributed to {pi}-{pi} interaction between {pi}-electron-depleted quinoline ring of Nor and {pi}-electron-rich PAHs. Compared with cation (Nor{sup +}) and anion (Nor{sup -}), zwitterion (Nor{sup {+-}}) of Nor increased PHEN and PYR sorption more pronounced due to additional cation-{pi} interaction between the sorbed Nor{sup {+-}} and PAHs. {sup 1}H NMR spectrum provided direct evidence for {pi}-{pi} and cation-{pi} complexation between PAHs and Nor{sup +} in solution by ring-current-induced upfield chemical shifts of amino group and methylene group of Nor{sup +}.

  18. Charge carrier density in Li-intercalated graphene

    KAUST Repository

    Kaloni, Thaneshwor P.

    2012-05-01

    The electronic structures of bulk C 6Li, Li-intercalated free-standing bilayer graphene, and Li-intercalated bilayer and trilayer graphene on SiC(0 0 0 1) are studied using density functional theory. Our estimate of Young\\'s modulus suggests that Li-intercalation increases the intrinsic stiffness. For decreasing Li-C interaction, the Dirac point shifts to the Fermi level and the associated band splitting vanishes. For Li-intercalated bilayer graphene on SiC(0 0 0 1) the splitting at the Dirac point is tiny. It is also very small at the two Dirac points of Li-intercalated trilayer graphene on SiC(0 0 0 1). For all the systems under study, a large enhancement of the charge carrier density is achieved by Li intercalation. © 2012 Elsevier B.V. All rights reserved.

  19. Sizing up surfactant synthesis.

    Science.gov (United States)

    Han, SeungHye; Mallampalli, Rama K

    2014-08-01

    Phosphatidylcholine is generated through de novo synthesis and remodeling involving a lysophospholipid. In this issue of Cell Metabolism, research from the Shimizu lab (Harayama et al., 2014) demonstrates the highly selective enzymatic behavior of lysophospholipid acyltransferases. The authors present an enzymatic model for phosphatidylcholine molecular species diversification that impacts surfactant formation.

  20. Genotoxicity of unmodified and organo-modified montmorillonite.

    Science.gov (United States)

    Sharma, Anoop Kumar; Schmidt, Bjørn; Frandsen, Henrik; Jacobsen, Nicklas Raun; Larsen, Erik Husfeldt; Binderup, Mona-Lise

    2010-07-19

    The natural clay mineral montmorillonite (Cloisite) Na+) and an organo-modified montmorillonite (Cloisite 30B) were investigated for genotoxic potential as crude suspensions and as suspensions filtrated through a 0.2-microm pore-size filter to remove particles above the nanometre range. Filtered and unfiltered water suspensions of both clays did not induce mutations in the Salmonella/microsome assay at concentrations up to 141microg/ml of the crude clay, using the tester strains TA98 and TA100. Filtered and unfiltered Cloisite) Na+ suspensions in culture medium did not induce DNA strand-breaks in Caco-2 cells after 24h of exposure, as tested in the alkaline comet assay. However, both the filtered and the unfiltered samples of Cloisite 30B induced DNA strand-breaks in a concentration-dependent manner and the two highest test concentrations produced statistically significantly different results from those seen with control samples (porgano-modified montmorillonite was caused by the organo-modifier. The detected organo-modifier mixture was synthesized and comet-assay results showed that the genotoxic potency of this synthesized organo-modifier was in the same order of magnitude at equimolar concentrations of organo-modifier in filtrated Cloisite) 30B suspensions, and could therefore at least partly explain the genotoxic effect of Cloisite) 30B.

  1. Cation exchange interaction between antibiotic ciprofloxacin and montmorillonite

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Chih-Jen [Department of Earth Sciences, National Cheng Kung University, 1 University Road, Tainan 70101, Taiwan (China); Department of Geosciences, National Taiwan University, Taipei 10617, Taiwan (China); Li, Zhaohui, E-mail: li@uwp.edu [Department of Earth Sciences, National Cheng Kung University, 1 University Road, Tainan 70101, Taiwan (China); Department of Geosciences, University of Wisconsin - Parkside, Kenosha, WI 53144 (United States); Jiang, Wei-Teh, E-mail: atwtj@mail.ncku.edu.tw [Department of Earth Sciences, National Cheng Kung University, 1 University Road, Tainan 70101, Taiwan (China); Jean, Jiin-Shuh; Liu, Chia-Chuan [Department of Earth Sciences, National Cheng Kung University, 1 University Road, Tainan 70101, Taiwan (China)

    2010-11-15

    Exploring the interactions between antibiotics and soils/minerals is of great importance in resolving their fate, transport, and elimination in the environment due to their frequent detection in wastewater, river water, sewage sludge and soils. This study focused on determining the adsorption properties and mechanisms of interaction between antibiotic ciprofloxacin and montmorillonite (SAz-1), a swelling dioctahedral mineral with Ca{sup 2+} as the main interlayer cation. In acidic and neutral aqueous solutions, a stoichiometric exchange between ciprofloxacin and interlayer cations yielded an adsorption capacity as high as 330 mg/g, corresponding to 1.0 mmol/g. When solution pH was above its pK{sub a2} (8.7), adsorption of ciprofloxacin was greatly reduced due to the net repulsion between the negatively charged clay surfaces and the ciprofloxacin anion. The uptake of ciprofloxacin expanded the basal spacing (d{sub 001}) of montmorillonite from 15.04 to 17.23 A near its adsorption capacity, confirming cation exchange within the interlayers in addition to surface adsorption. Fourier transform infrared results further suggested that the protonated amine group of ciprofloxacin in its cationic form was electrostatically attracted to negatively charged sites of clay surfaces, and that the carboxylic acid group was hydrogen bonded to the basal oxygen atoms of the silicate layers. The results indicate that montmorillonite is an effective sorbent to remove ciprofloxacin from water.

  2. Cation exchange interaction between antibiotic ciprofloxacin and montmorillonite.

    Science.gov (United States)

    Wang, Chih-Jen; Li, Zhaohui; Jiang, Wei-Teh; Jean, Jiin-Shuh; Liu, Chia-Chuan

    2010-11-15

    Exploring the interactions between antibiotics and soils/minerals is of great importance in resolving their fate, transport, and elimination in the environment due to their frequent detection in wastewater, river water, sewage sludge and soils. This study focused on determining the adsorption properties and mechanisms of interaction between antibiotic ciprofloxacin and montmorillonite (SAz-1), a swelling dioctahedral mineral with Ca(2+) as the main interlayer cation. In acidic and neutral aqueous solutions, a stoichiometric exchange between ciprofloxacin and interlayer cations yielded an adsorption capacity as high as 330 mg/g, corresponding to 1.0 mmol/g. When solution pH was above its pK(a2) (8.7), adsorption of ciprofloxacin was greatly reduced due to the net repulsion between the negatively charged clay surfaces and the ciprofloxacin anion. The uptake of ciprofloxacin expanded the basal spacing (d(001)) of montmorillonite from 15.04 to 17.23 A near its adsorption capacity, confirming cation exchange within the interlayers in addition to surface adsorption. Fourier transform infrared results further suggested that the protonated amine group of ciprofloxacin in its cationic form was electrostatically attracted to negatively charged sites of clay surfaces, and that the carboxylic acid group was hydrogen bonded to the basal oxygen atoms of the silicate layers. The results indicate that montmorillonite is an effective sorbent to remove ciprofloxacin from water. Copyright © 2010 Elsevier B.V. All rights reserved.

  3. Preparation and Microstructure of Al-pillared Interlayered Montmorillonite

    Institute of Scientific and Technical Information of China (English)

    CAO Ming-li; ZHU Ying-bo; YU Yong-fu

    2002-01-01

    Al-pillared interlayered montmorillonite ( Al-PILM) was prepared using the artificial Na-montmorillonite from the Qingfengshan bentonite mine as a starting material mixed with Al-pillaring solutions. The microstructure of the materials was stndied by an X-ray powder diffractometer and a Fourier transform infrared ( FTIR ) spectrometer. The results indicated that the basal spacing [ d (001) value ] of the materials was increased significantly to 1.9194 nm relative to Na-montmorillonite (1.2182 nm). After calcined for 2 h at 300℃, the basal spacing was stabilized at 1. 8394 nm and the layered structure of the materials was not destroyed. Thermal analysis was conducted by a thermal gravimetry and differential thermal analysis ( TG - DTA ) instrument, it showed that Al - PILM lost physically adsorbed water below 230.6℃ and water formed by dehydroxylation of the pillars at around 497.1℃, with a peak of the phase transformation at 903.0℃.

  4. Thermodynamics of selenium sorption on alumina and montmorillonite

    Directory of Open Access Journals (Sweden)

    Jean-Pierre Morel

    2015-12-01

    Full Text Available The effect of pH and temperature on the thermodynamics of selenium sorption on alumina and montmorillonite was investigated. The equilibrium constants were obtained from batch experiments carried out at 25 and 40°C, under acidic and near to neutral conditions. Microcalorimetry was used to measure directly the enthalpy change upon sorption. These data were analysed by taking into account the different reactions that occur during the sorption process (the acid–base equilibria in the bulk solution on the one hand and the complexation equilibria between surface sites of the solid and solution species on the other hand. This was done using a simple surface model which assumes that the thermodynamic properties of the aluminol surface sites of both alumina and montmorillonite are identical. Two of the considered reactions were found to predominate, one under acidic conditions and one at near neutral pH. The microcalorimetric data allowed to check that the temperature effect on selenium sorption on alumina and montmorillonite can be correctly predicted simply using the above assumption concerning the sorption sites and by applying van’t Hoff relation both to the homogeneous and heterogeneous reactions.

  5. Effect of poly(vinyl pyrrolidone) on the morphology and physical properties of poly(vinyl alcohol)/sodium montmorillonite nanocomposite films

    Institute of Scientific and Technical Information of China (English)

    Dibyendu Mondal; Md. Masud R. Mollick; Biplab Bhowmick; Dipanwita Maity; Mrinal K. Bain; Dipak Rana; Asis Mukhopadhyay; Kausik Dana; Dipankar Chattopadhyay

    2013-01-01

    Nanocomposites of poly(vinyl alcohol) (PVA), poly(vinyl pyrrolidone) (PVP) and sodium montmorillonite (NaþMMT) were prepared by solution mixing and then cast into films. X-ray diffraction analysis and images of transmission electron microscopy establish the formation of PVA/NaþMMT intercalated nanocomposite. Exfoliated and highly intercalated PVA/PVP/NaþMMT nanocomposite formed in the presence of PVP. Inclusion of PVP in PVA/NaþMMT matrix enhances the hydrogen bonding interactions between PVA and NaþMMT and thus increases the mechanical properties and thermal stability of PVA/PVP/NaþMMT nanocomposites compared to PVA/NaþMMT nanocomposite. The interactions between PVA, PVP and NaþMMT were established by the Fourier transform infrared spectroscopy. The moisture absorption tendency of both the PVA and PVA/PVP films reduced after the incorporation of NaþMMT at 75% constant relative humidity. Differential scanning calorimetry studies show that the presence of PVP and NaþMMT both are responsible for reducing the heat of fusion, and crystallinity of PVA. The flow behavior of the PVA, PVA/PVP and its nanocomposite solutions has been also studied. Water vapor permeability of PVA/PVP/NatMMT composite films decreased in the presence of nanoclay due to increasing tortuous paths for diffusion.

  6. The intercalation chemistry of layered iron chalcogenide superconductors

    Science.gov (United States)

    Vivanco, Hector K.; Rodriguez, Efrain E.

    2016-10-01

    The iron chalcogenides FeSe and FeS are superconductors composed of two-dimensional sheets held together by van der Waals interactions, which makes them prime candidates for the intercalation of various guest species. We review the intercalation chemistry of FeSe and FeS superconductors and discuss their synthesis, structure, and physical properties. Before we review the latest work in this area, we provide a brief background on the intercalation chemistry of other inorganic materials that exhibit enhanced superconducting properties upon intercalation, which include the transition metal dichalcogenides, fullerenes, and layered cobalt oxides. From past studies of these intercalated superconductors, we discuss the role of the intercalates in terms of charge doping, structural distortions, and Fermi surface reconstruction. We also briefly review the physical and chemical properties of the host materials-mackinawite-type FeS and β-FeSe. The three types of intercalates for the iron chalcogenides can be placed in three categories: 1.) alkali and alkaline earth cations intercalated through the liquid ammonia technique; 2.) cations intercalated with organic amines such as ethylenediamine; and 3.) layered hydroxides intercalated during hydrothermal conditions. A recurring theme in these studies is the role of the intercalated guest in electron doping the chalcogenide host and in enhancing the two-dimensionality of the electronic structure by spacing the FeSe layers apart. We end this review discussing possible new avenues in the intercalation chemistry of transition metal monochalcogenides, and the promise of these materials as a unique set of new inorganic two-dimensional systems.

  7. Electrical and Dielectric Properties of Polyaniline and Polyaniline/Montmorillonite Nanocomposite Prepared by Solid Reaction Using Spectroscopy Impedance

    Directory of Open Access Journals (Sweden)

    Imene Bekri-Abbes

    2015-01-01

    Full Text Available The combination of two components with uniform distribution in nanoscale is expected to facilitate wider applications of the material. In this study, polyaniline (PAn and polyaniline/montmorillonite (Mt nanocomposite were prepared by solid reaction using persulfate of ammonium as oxidant. The phase composition and morphology of the nanocomposite were characterized by FTIR, UV-visible spectroscopy, X-ray diffractometer, thermal gravimetric analysis, and scanning electron microscopy. The electrical and dielectric properties were determined using spectroscopy impedance. The analysis of UV-visible and FTIR spectroscopy demonstrated that aniline chloride has been polymerized into PAn in its conducting emeraldine form. Thermogravimetric analysis suggested that PAn chains intercalated in the clay host are more thermally stable than those of free PAn prepared by solid-solid reaction. Electrical measurements were carried out using the complex impedance technique in the frequency range of 10−2 to 104 Hz at different temperatures. The ac conductivity data of different nanocomposites were analyzed as a function of frequency and temperature. It has been found that the incorporation of inorganic clay phase into polyaniline matrix has an effect on the electrical and dielectric properties of the nanomaterial.

  8. Interaction processes of ciprofloxacin with graphene oxide and reduced graphene oxide in the presence of montmorillonite in simulated gastrointestinal fluids.

    Science.gov (United States)

    Ma, Shuai; Si, Yang; Wang, Fei; Su, Lei; Xia, CongCong; Yao, Jun; Chen, Huilun; Liu, Xingyu

    2017-05-31

    This study investigated the interaction processes of ciprofloxacin (CIP) with graphene oxide (GO) and reduced GO (rGO) in presence of montmorillonite (Mont) in simulated gastrointestinal fluids. The order of CIP adsorption affinity was rGO+Mont > GO+Mont > rGO+Mont+pepsin > rGO > GO+Mont+pepsin > Mont > Mont+pepsin > GO > rGO+pepsin > GO+pepsin in simulated gastric fluid. Mont enhanced the adsorption of CIP on GO and rGO due to hydrated Si species coating on GO and rGO in the simulated gastric fluid. Meanwhile, π-π interaction between CIP and graphene caused the great shift of two cyclopropyl CH2 and one cyclopropyl in CIP molecules. And GO, rGO, and Mont interacted mainly with CIP by COOH groups. CIP and pepsin molecules could intercalate and increase the basal spacing of Mont as well. After the various interaction systems of adsorbent-adsorbate transferring to the simulated intestinal fluid, CIP was continuously adsorbed by GO and rGO. In addition, adsorbed CIP was released from Mont into the solution through electrostatic repulsion. The decrease ratio of CIP was the lowest in the GO/rGO+Mont+pepsin systems. Therefore, the mixture of Mont and GO/rGO decreased the CIP concentration in gastrointestinal fluid to weaken further antibiotic activity of CIP.

  9. Morphological Evaluation of Variously Intercalated Pre-baked Clay

    Directory of Open Access Journals (Sweden)

    Ullah Hameed

    2014-06-01

    Full Text Available The use of porous materials is enjoying tremendous popularity and attention of the advance scientific communities due to their excellent adsorptive and catalytic activities. Clays are one of the most important candidates in the porous community which shows the above mentioned activities after modifing with a different intercalating agent. The paper is focused on the infiuence of some inorganic intercalating agents (NaOH on the morphology of the variously intercalated clay samples. The alkali metal was used as the inorganic intercalating agent. The effect of intercalation temperature, intercalation agent concentration and intercalation time on the pre-baked clay morphology were also part of the study. Scanning electron microscopy (SEM study was performed to evaluate the morphological changes of the resultant intercalates. Different morphological properties were improved significantly in the case of the inorganically modified clay samples. Thus, such intercalations are suggested to be effective if the clays under study are to be used for different industrial process at elevated conditions.

  10. Photoluminescence of CdSe/ZnS core-shell quantum dots stabilized in water with a pseudopeptidic gemini surfactant

    Science.gov (United States)

    Rubio, Jenifer; Izquierdo, M. Angeles; Burguete, M. Isabel; Galindo, Francisco; Luis, Santiago V.

    2011-09-01

    The use of pseudopeptidic gemini surfactants as stabilizers of hydrophobic quantum dots in water is discussed. Compound 1a acts as an intercalator with hydrophobic ligands of QDs transferring them from toluene to pure water yielding a fluorescent nanoparticle resistant to quenching by chloride anion (up to 0.1 M).The use of pseudopeptidic gemini surfactants as stabilizers of hydrophobic quantum dots in water is discussed. Compound 1a acts as an intercalator with hydrophobic ligands of QDs transferring them from toluene to pure water yielding a fluorescent nanoparticle resistant to quenching by chloride anion (up to 0.1 M). Electronic supplementary information (ESI) available: General experimental and synthetic procedures; NMR, ESI-MS spectra; FTIR, TEM and stability studies of water soluble QDs, fluorescent decay curves, effect of chloride, effect of concentration of 1a, and calculation of cmc. See DOI: 10.1039/c1nr10680e

  11. [Adsorption of aflatoxin on montmorillonite modified by low-molecular-weight humic acids].

    Science.gov (United States)

    Yao, Jia-Jia; Kang, Fu-Xing; Gao, Yan-Zheng

    2012-03-01

    The adsorption of a typical biogenic toxin aflatoxin B1 on montmorillonite modified by low-molecular-weight humic acids (M(r) aflatoxin B1 until amounting to the maximal capacity, and then the adsorbed aflatoxin B1 slowly released into solution and reached the sorption equilibrium state after 12 h. The sorption isotherm of aflatoxin B1 by montmorillonite could be well described by Langmiur model, while the sorption isotherm by humic acid-modified montmorillonite was well fitted by using the Freundlich model. The modification of the montmorillonite with humic acids obviously enhanced its adsorption capacity for aflatoxin B1, and the amounts of aflatoxin adsorbed by modified montmorillonite were obviously higher than those by montmorillonite. The sorption enhancement by humic acid modification was attributed to (1) the enlarged adsorption sites which owed to the surface collapse of crystal layers induced by organic acids, and (2) the binding of aflatoxin with the humic acid sorbed on mineral surface. In addition, the adsorption amounts of aflatoxin by montmorillonite and modified montmorillonite increased with the increase of pH values in solution, and more significant enhancement was observed for the latter than the former, which attributed to the release of humic acids from the modified montmorillonite with the high pH values in solution. This indicates that increasing the pH values resulted in the enhanced hydrophilic property and the release of the organic acids presented in modified montmorillonite, and more sorption sites were available for aflatoxin on the modified montmorillonite. Results of this work would strengthen our understanding of the behavior and fate of biological contaminants in the environment.

  12. Correlation between the extent of catalytic activity and charge density of montmorillonites.

    Science.gov (United States)

    Ertem, Gözen; Steudel, Annett; Emmerich, Katja; Lagaly, Gerhard; Schuhmann, Rainer

    2010-09-01

    The clay mineral montmorillonite is a member of the phyllosilicate group of minerals, which has been detected on martian soil. Montmorillonite catalyzes the condensation of activated monomers to form RNA-like oligomers. Extent of catalysis, that is, the yield of oligomers, and the length of the longest oligomer formed in these reactions widely varies with the source of montmorillonite (i.e., the locality where the mineral is mined). This study was undertaken to establish whether there exists a correlation between the extent of catalytic property and the charge density of montmorillonites. Charge density was determined by saturating the montmorillonites with alkyl ammonium cations that contained increasing lengths of alkyl chains, [CH₃-(CH₂)(n)-NH₃](+), where n = 3-16 and 18, and then measuring d(₀₀₁), interlayer spacing of the resulting montmorillonite-alkyl ammonium-montmorillonite complex by X-ray diffractometry (XRD). Results demonstrate that catalytic activity of montmorillonites with lower charge density is superior to that of higher charge density montmorillonite. They produce longer oligomers that contain 9 to 10 monomer units, while montmorillonite with high charge density catalyzes the formation of oligomers that contain only 4 monomer units. The charge density of montmorillonites can also be calculated from the chemical composition if elemental analysis data of the pure mineral are available. In the next mission to Mars, CheMin (Chemistry and Mineralogy), a combined X-ray diffraction/X-ray fluorescence instrument, will provide information on the mineralogical and elemental analysis of the samples. Possible significance of these results for planning the future missions to Mars for the search of organic compounds and extinct or extant life is discussed.

  13. Discriminating Intercalative Effects of Threading Intercalator Nogalamycin, from Classical Intercalator Daunomycin, Using Single Molecule Atomic Force Spectroscopy

    OpenAIRE

    T.; Banerjee; Banerjee, S.; Sett, S.; Ghosh, S.; T. Rakshit; Mukhopadhyay, R.

    2016-01-01

    DNA threading intercalators are a unique class of intercalating agents, albeit little biophysical information is available on their intercalative actions. Herein, the intercalative effects of nogalamycin, which is a naturally-occurring DNA threading intercalator, have been investigated by high-resolution atomic force microscopy (AFM) and spectroscopy (AFS). The results have been compared with those of the well-known chemotherapeutic drug daunomycin, which is a non-threading classical intercal...

  14. Intercalation of water into lithium. beta. -alumina

    Energy Technology Data Exchange (ETDEWEB)

    Dudney, N J; Bates, J B; Wang, J C; Brown, G M; Larson, B C; Engstrom, H

    1981-01-01

    Infrared absorption, neutron diffraction and weight loss techniques have been used to investigate the hydration of single crystals of Li ..beta..-alumina. The hydration is a reversible intercalation reaction. Up to approximately two water molecules per formula unit can penetrate the conduction plane. Other protonated species are formed from the dissociation of the molecular water. The rate of hydration is controlled by the diffusion of water in the conduction plane. A likely diffusion mechanism requires dissociation of the water and an interstitialcy motion of the oxygen.

  15. Sorption of a nonionic surfactant Tween 80 by minerals and soils.

    Science.gov (United States)

    Kang, Soyoung; Jeong, Hoon Young

    2015-03-02

    Batch experiments were conducted to evaluate Tween 80 sorption by oxides, aluminosilicates, and soils. For oxides, the sorption by silica and alumina follow linear isotherms, and that by hematite follows a Langmuir isotherm. Considering isotherm type and surface coverage, Tween 80 may partition into the silica/alumina-water interface, whereas it may bind to hematite surface sites. Among aluminosilicates, montmorillonite shows the greatest sorption due to the absorption of Tween 80 into interlayers. For other aluminosilicates, it sorbs to surfaces, with the sorption increasing as plagioclaseTween 80 sorption. The greater sorption by untreated soils than H2O2-treated soils indicates that soil organic matter is a vital sorbent. The sorption hysteresis, contributed to by clay minerals and soil organic matter, is characterized by the greater sorption during the desorption than the sorption stages. This suggests the potential difficulty in removing surfactants from soils. Also, sorption of surfactants can adversely affect surfactant-enhanced remediation by decreasing the aquifer permeability and the availability of surfactants for micellar solubilization.

  16. Effect of modified montmorillonites on the biodegradation and adsorption of biomarkers such as hopanes, steranes and diasteranes.

    Science.gov (United States)

    Ugochukwu, Uzochukwu C; Head, Ian M; Manning, David A C

    2013-12-01

    The effect of modified montmorillonites on the biodegradation and adsorption of selected steranes, diasteranes and hopanes was investigated in aqueous clay/oil microcosm experiments with a hydrocarbon degrading microorganism community. The unmodified montmorillonite was treated with didecyldimethylammonium bromide, hydrochloric acid and the relevant metallic chloride to produce organomontmorillonite, acid activated montmorillonite and homoionic montmorillonite respectively which were used in this study. The study indicated that organomontmorillonite, acid activated montmorillonite and potassium montmorillonite did not support the biodegradation of the selected steranes, diasteranes and hopanes as alteration of the biomarkers via biodegradation varied from a paltry 2-6 %. The adsorption of the selected biomarkers on acid activated montmorillonite and organomontmorillonite was also poor. However, adsorption of the biomarkers on potassium montmorillonite was relatively high. Sodium montmorillonite and unmodified montmorillonite appear to stimulate the biodegradation of the selected biomarkers moderately (30-35 %) with adsorption occurring at low level. Calcium montmorillonite and ferric montmorillonite effected significant biodegradation (51-60 %) of the selected biomarkers.

  17. Preparation and Characterization of Modified Montmorillonite/Paraffin Phase Change Microcapsules for Energy Storage

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    LIN Sen

    2017-03-01

    Full Text Available The phase change microcapsules of modified montmorillonite/paraffin were prepared by Pickering emulsion method. Analytic techniques of optical microscopy, scanning electron microscopy(SEM, infrared spectroscopy(FTIR, differential scanning calorimetry(DSC and thermogravimetry(TG were utilized for characterizing chemical structure, morphology and thermal properties. Results show that modified montmorillonite as a new type wall material has excellent performance for protecting core material of paraffin. FTIR spectra of phase change of modified montmorillonite/paraffin microcapsules shows that their characteristic peaks match with corresponding peaks of pure paraffin and modified montmorillonite. DSC results indicate that modified montmorillonite/paraffin microcapsules have similar solid-liquid phase change temperature with pure paraffin. The phase transition enthalpy values of microcapsules with paraffin contents varying from 55% to 80% are 110.5-147.2J/g, indicating that microcapsules have excellent thermal storage performance and the phase change properties can be adjusted by changing contents of paraffin. TG results confirm that modified montmorillonite/paraffin microcapsules have outstanding thermal stability. The presented study indicates that modified montmorillonite is a suitable wall material for preparing paraffin microcapsule. Modified montmorillonite/paraffin microcapsules have advantages of low cost and high performance with a great application potential in the field of thermal storage.

  18. Preparation and Characterization of the Antibacterial Zn2+ or/and Ce3+ Loaded Montmorillonites

    Institute of Scientific and Technical Information of China (English)

    TAN Shao-Zao; ZHANG Kui-Hua; ZHANG Li-Ling; XIE Yu-Shan; LIU Ying-Liang

    2008-01-01

    A series of modified montmorillonites including Zn2+ loaded montmorillonite(Zn/MMT),Ce3+loaded montmorillonite(Ce/MMT)and zn2+ -Ce3+ loaded montmorillonites(Zn-Ce/MMT)were prepared by an ion-exchange reaction,and characterized using X-ray photoelectron spectroscopy(XPS),X-ray diffraction(XRD),and scanning electron microscopy(SEM).The specific surface areas,zeta potentials and antibacterial activity of the modified montmorillonites were also investigated.Zinc and cerium were proved to be present as bivalent zinc state and trivalent cerium state in the modified montmorillonites.For the modified montmorillonites,the d001 basal spacings increased and the particles were formed of irregular shapes.The antibacterial activity of the modified montmorillo nites was enhanced with the increase of specific surface areas and zeta potentials,and Zn2+ -Ce3+ loaded montmorillonites displayed obvious synergistic antibacterial effeCt.When Zn/Ce atomic ratio Was 1.24.the Zn-Ce/MMT showed high antibacterial efficiency and broad-spectrum antibacterial activity,possessing the MIC against Escherichia coli,Staphylococcus aureus,Candida albicans and Mucor of 1500,1000,2000 and 3000 mg·L-1,respectively.

  19. Acidic Montmorillonite/Cordierite Monolithic Catalysts for Cleavage of Cumene Hydroperoxide

    Institute of Scientific and Technical Information of China (English)

    Li Han; Yanjun Wang; Jie Zhang; Zhigang Lei; Chongpin Huang; Biaohua Chen

    2014-01-01

    In this work, a series of acidic montmorillonite/cordierite monolithic catalysts were prepared by a coating method using silica sol as the binder. The morphology and structure of the acidic montmoril onite/cordierite samples were characterized by means of X-ray diffraction (XRD), N2 adsorption/desorption isotherms, and scanning electron microscope (SEM). The cleavage of cumene hydroperoxide (CHP) in a conventional fixed-bed reactor was chosen as a model reaction to evaluate the catalytic activity of the monolithic catalysts. The influences of acidic montmorillonite loading, reaction temperature, CHP concentration, and weight hourly space velocity (WHSV) on the catalytic activity and selectivity of phenol were studied. The results indicated that the obtained acidic montmorillonite/cordierite monolithic catalysts were firm and compact, and the loading of acidic montmorillonite was found to reach 40%(by mass) after three coating operations. The surface area of acidic montmorillonite/cordierite catalysts increases greatly as acidic montmorillonite loading increases due to higher surface area of acidic montmorillonite. Under the optimal reaction conditions (acidic montmorillonite loading of 32.5%(by mass), temperature of 80 °C, a mass ratio of CHP to acetone of 1:3, and WHSV of CHP of 90 h-1), the conversion of CHP can reach 100%, and the selectivity of phenol is up to 99.8%.

  20. MICROBIAL SURFACTANTS. I. GLYCOLIPIDS

    Directory of Open Access Journals (Sweden)

    Pirog T. Р.

    2014-02-01

    Full Text Available The review is devoted to surface-active glycolipids. The general characteristics, the physiological role of the rhamnolipids, trehalose lipids, sophorolipids, mannosylerythritol lipids and their traditional producers — the representatives of the genera Pseudozyma, Pseudomonas, Rhodococcus and Candida are given. The detailed analysis of the chemical structure, the stages of the biosynthesis and the regulation of some low molecular glycolipids are done. The own experimental data concerning the synthesis intensification, the physiological role and the practical use of Rhodococcus erythropolis IMV Ac-5017, Acinetobacter calcoaceticus IMV B-7241 and Nocardia vaccinii IMV B-7405 surfactants, which are a complex of the glyco-, phospho-, amino- and neutral lipids (glycolipids of all strains are presented by trehalose mycolates are summarized. It was found that R. erythropolis IMV Ac-5017, A. calcoaceticus IMV B-7241 and N. vaccinii IMV B-7405 surfactants have protective, antimicrobial and antiadhesive properties. It was shown that R. erythropolis IMV Ac-5017, A. calcoaceticus IMV B-7241 and N. vaccinii IMV B-7405 surfactants preparation of cultural liquid intensified the degradation of oil in water due to the activation of the natural petroleum-oxidizing microflora.

  1. MICROBIAL SURFACTANTS. II. LIPOPEPTIDES

    Directory of Open Access Journals (Sweden)

    T. P. Pirog

    2014-04-01

    Full Text Available The classification and the chemical structure of the lipopeptides and their producers (bacteria of the genera Bacillus and Pseudomonas are given. The role of the lipopeptides in cells motility, biofilm formation, metal binding and xenobiotics degradation and their action on the cells of pro- and eukaryotes is summarized. The stages of the nonribosomal lipopeptides synthesis and the role of two-component (GacA/GacS, ComA/ComP and the quorum system regulation of this process are shown. The potential of lactic acid bacteria and marine microorganisms as alternative surfactants producers (glycolipids, lipopeptides, phospholipids and fatty acids, glycolipopeptides are discussed. Their productivity and advantages over traditional producers are given as well. The properties of surfactants synthesized by lactic acid bacteria (the reduction of the surface tension, the critical micelle concentration, the stability in a wide range of pH, the temperature, the biological activity are summarized. Surfactants of nonpathogenic probiotic bacteria could be used as effective antimicrobial agents and antiadhesive and marine producers which able to synthesize unique metabolites that are not produced by other microorganisms.

  2. Comparison of lithium and sodium intercalation materials

    Directory of Open Access Journals (Sweden)

    Vujković Milica

    2015-01-01

    Full Text Available Low abundance of lithium in Earth’s crust and its high participation in overall cost of lithium-ion batteries incited intensive investigation of sodium-ion batteries, in hope that they may become similar in basic characteristics: specific energy and specific power. Furthermore, over the last years the research has been focused on the replacement of organic electrolytes of Li- and Na-ion batteries, by aqueous electrolytes, in order to simplify the production and improve safety of use. In this lecture, some recent results on the selected intercalation materials are presented: layered structure vanadium oxides, olivine and nasicon phosphates, potentially usable in both Li and Na aqueous rechargeable batteries. After their characterization by X-ray diffraction and electron microscopy, the electrochemical behavior was studied by both cyclic voltammetry and hronopotenciometry. By comparing intercalation kinetics and coulombic capacity of these materials in LiNO3 and NaNO3 solutions, it was shown that the following ones: Na1.2V3O8, Na2V6O16/C , NaFePO4/C and NaTi2(PO43/C may be used as electrode materials in aqueous alkali-ion batteries.

  3. Polysulfide intercalated layered double hydroxides for metal capture applications

    Science.gov (United States)

    Kanatzidis, Mercouri G.; Ma, Shulan

    2017-04-04

    Polysulfide intercalated layered double hydroxides and methods for their use in vapor and liquid-phase metal capture applications are provided. The layered double hydroxides comprise a plurality of positively charged host layers of mixed metal hydroxides separated by interlayer spaces. Polysulfide anions are intercalated in the interlayer spaces.

  4. Holding on and letting go: cadherin turnover in cell intercalation.

    Science.gov (United States)

    Morita, Hitoshi; Heisenberg, Carl-Philipp

    2013-03-25

    In zebrafish early development, blastoderm cells undergo extensive radial intercalations, triggering the spreading of the blastoderm over the yolk cell and thereby initiating embryonic body axis formation. Now reporting in Developmental Cell, Song et al. (2013) demonstrate a critical function for EGF-dependent E-cadherin endocytosis in promoting blastoderm cell intercalations.

  5. PYRENE INTERCALATING NUCLEIC ACIDS WITH A CARBON LINKER

    DEFF Research Database (Denmark)

    Østergaard, Michael E.; Wamberg, Michael Chr.; Pedersen, Erik Bjerregaard

    2011-01-01

    geminally attached. Fluorescence studies of this intercalating nucleic acid with the pyrene moieties inserted as a bulge showed formation of an excimer band. When a mismatch was introduced at the site of the intercalator, an excimer band was formed for the destabilized duplexes whereas an exciplex band...

  6. Attenuation of cytotoxic natural product DNA intercalating agents by caffeine.

    Science.gov (United States)

    Hill, Gabrielle M; Moriarity, Debra M; Setzer, William N

    2011-01-01

    Many anti-tumor drugs function by intercalating into DNA. The xanthine alkaloid caffeine can also intercalate into DNA as well as form π-π molecular complexes with other planar alkaloids and anti-tumor drugs. The presence of caffeine could interfere with the intercalating anti-tumor drug by forming π-π molecular complexes with the drug, thereby blocking the planar aromatic drugs from intercalating into the DNA and ultimately lowering the toxicity of the drug to the cancer cells. The cytotoxic activities of several known DNA intercalators (berberine, camptothecin, chelerythrine, doxorubicin, ellipticine, and sanguinarine) on MCF-7 breast cancer cells, both with and without caffeine present (200 μg/mL) were determined. Significant attenuation of the cytotoxicities by caffeine was found. Computational molecular modeling studies involving the intercalating anti-tumor drugs with caffeine were also carried out using density functional theory (DFT) and the recently developed M06 functional. Relatively strong π-π interaction energies between caffeine and the intercalators were found, suggesting an "interceptor" role of caffeine protecting the DNA from intercalation.

  7. Polysulfide intercalated layered double hydroxides for metal capture applications

    Energy Technology Data Exchange (ETDEWEB)

    Kanatzidis, Mercouri G.; Ma, Shulan

    2017-04-04

    Polysulfide intercalated layered double hydroxides and methods for their use in vapor and liquid-phase metal capture applications are provided. The layered double hydroxides comprise a plurality of positively charged host layers of mixed metal hydroxides separated by interlayer spaces. Polysulfide anions are intercalated in the interlayer spaces.

  8. Surfactants at the Design Limit.

    Science.gov (United States)

    Czajka, Adam; Hazell, Gavin; Eastoe, Julian

    2015-08-04

    This article analyzes how the individual structural elements of surfactant molecules affect surface properties, in particular, the point of reference defined by the limiting surface tension at the aqueous cmc, γcmc. Particular emphasis is given to how the chemical nature and structure of the hydrophobic tails influence γcmc. By comparing the three different classes of surfactants, fluorocarbon, silicone, and hydrocarbon, a generalized surface packing index is introduced which is independent of the chemical nature of the surfactants. This parameter ϕcmc represents the volume fraction of surfactant chain fragments in a surface film at the aqueous cmc. It is shown that ϕcmc is a useful index for understanding the limiting surface tension of surfactants and can be useful for designing new superefficient surfactants.

  9. K-intercalated carbon systems: Effects of dimensionality and substrate

    KAUST Repository

    Kaloni, Thaneshwor P.

    2012-06-01

    Density functional theory is employed to investigate the electronic properties of K-intercalated carbon systems. Young\\'s modulus indicates that the intercalation increases the intrinsic stiffness. For K-intercalated bilayer graphene on SiC(0001) the Dirac cone is maintained, whereas a trilayer configuration exhibits a small splitting at the Dirac point. Interestingly, in contrast to many other intercalated carbon systems, the presence of the SiC(0001) substrate does not suppress but rather enhances the charge carrier density. Reasonably high values are found for all systems, the highest carrier density for the bilayer. The band structure and electron-phonon coupling of free-standing K-intercalated bilayer graphene points to a high probability for superconductivity in this system. © 2012 Europhysics Letters Association.

  10. Quasi-freestanding graphene on Ni(111) by Cs intercalation

    KAUST Repository

    Alattas, M.

    2016-05-26

    A possible approach to achieve quasi-freestanding graphene on a substrate for technological purpose is the intercalation of alkali metal atoms. Cs intercalation between graphene and Ni(111) therefore is investigated using density functional theory, incorporating van der Waals corrections. It is known that direct contact between graphene and Ni(111) perturbs the Dirac states. We find that Cs intercalation restores the linear dispersion characteristic of Dirac fermions, which agrees with experiments, but the Dirac cone is shifted to lower energy, i.e., the graphene sheet is n-doped. Cs intercalation therefore decouples the graphene sheet from the substrate except for a charge transfer. On the other hand, the spin polarization of Ni(111) does not extend through the intercalated atoms to the graphene sheet, for which we find virtually spin-degeneracy.

  11. Quasi-freestanding graphene on Ni(111) by Cs intercalation

    KAUST Repository

    Alattas, Maha

    2017-01-08

    It is of technological interest to achieve quasi-freestanding graphene on a substrate. A possible approach is the intercalation of alkali metal atoms. Cs intercalation between graphene and Ni(111) is investigated using density functional theory, incorporating van der Waals corrections. It is known that direct contact between graphene and Ni(111) perturbs the Dirac states. Cs intercalation restores the linear dispersion characteristic of Dirac fermions, which is in agreement with experiments1, but the Dirac cone is shifted to lower energy, i.e., the graphene sheet is n-doped. Cs intercalation therefore effectively decouples the graphene sheet from the substrate except for a charge transfer. On the other hand, the spin polarization of Ni(111) does not extend through the intercalated atoms to the graphene sheet, for which we find virtually spin-degeneracy.

  12. BINDING ISOTHERMS SURFACTANT-PROTEINS

    Directory of Open Access Journals (Sweden)

    Elena Irina Moater

    2011-12-01

    Full Text Available The interactions between surfactants and proteins shows some similarities with interactions between surfactants and polymers, but the hydrophobic amphoteric nature of proteins and their secondary and tertiary structure components make them different from conventional polymer systems. Many studies from the past about surfactant - proteins bonding used the dialysis techniques. Other techniques used to determine the binding isotherm, included ultrafiltration, ultracentrifugation, potentiometry, ion-selective electrode method and surface tension. High affinity isotherms which are typical of an anionic surfactant - protein bonding, exhibit an initial increase steep followed by a slow growth region and then a vertical growth above a certain concentration. This isotherm is typical of ionic surfactant to protein binding. Often the high affinity initial bond appears at very low concentrations of surfactant and therefore in some protein-surfactant systems, the exact shape of the isotherm in this region may be missing. The surfactant - protein binding is influenced by a number of variables such as the nature and chain length of surfactant, pH, ionic strength, temperature, nature of this protein and additives.

  13. Oligomerization reactions of deoxyribonucleotides on montmorillonite clay - The effect of mononucleotide structure, phosphate activation and montmorillonite composition on phosphodiester bond formation

    Science.gov (United States)

    Ferris, James P.; KAMALUDDIN; Ertem, Gozen

    1990-01-01

    The 2(prime)-d-5(prime)-GMP and 2(prime)-d-5(prime)-AMP bind 2 times more strongly to montmorillonite 22A than do 2(prime)-d-5(prime)-CMP and 5(prime)-TMP. The dinucleotide d(pG)2 forms in 9.2 percent yield and the cyclic dinucleotide c(dpG)2 in 5.4 percent yield in the reaction of 2(prime)-d-5(prime)-GMP with EDAC in the presence of montmorillonite 22A. The yield of dimers which contain the phosphodiester bond decreases as the reaction medium is changed from 0.2 M NaCl to a mixture of 0.2 M NaCl and 0.075 M MgCl2. A low yield of d(pA)2 was observed in the condensation reaction of 5(prime)-ImdpA on montmorillonite 22A. The yield of d(pA)2 obtained when EDAC is used as the condensing agent increases with increasing iron content of the Na(+)-montmorillonite used as catalyst. Evidence is presented which shows that the acidity of the Na(+)-montmorillonite is a necessary but not sufficient factor for the montmorillonite catalysis of phosphodiester bond formation.

  14. Preparation, morphology, and antibacterial properties of polyacrylonitrile/montmorillonite/silver nanocomposites

    Energy Technology Data Exchange (ETDEWEB)

    Hwang, Jiunn-Jer, E-mail: jiunnjer1@hotmail.com [Department of Chemical Engineering, Army Academy, Taoyuan 32092, Taiwan, ROC (China); Ma, Te-Wei [Department of Chemical Engineering, Army Academy, Taoyuan 32092, Taiwan, ROC (China)

    2012-10-15

    Modified montmorillonite was intercalated with polyacrylonitrile (PAN) and then reacted with AgNO{sub 3}. Plate-like clay, with anionic charges and a large surface area, was the dispersant of the silver ions. Aqueous 3% NaBH{sub 4}-reduced Ag{sup +} (in situ) was utilized to prepare a series of polyacrylonitrile/montmorillonite/silver nanocomposites (PAN/o-MMT/Ag). The presence of silver particles with diameters of 50-100 nm was confirmed by X-ray and SEM observations. XRD diffraction peaks were obtained at 38.2 Degree-Sign , 44.4 Degree-Sign , 64.6 Degree-Sign and 77.6 Degree-Sign . AFM and TEM were used to evaluate the surface roughness of the nanocomposites and the dispersion of the silver nanoparticles (AgNPs) therein nanocomposites. Adding o-MMT made the nanocomposites rougher. The AgNPs were primarily located in the layered silicate nanofiller. In addition, the silver in nanocomposites was released to the water and dominant form of silver was nanoparticle in the water was verified by particle size analyzer and atomic absorption spectrometer. A higher F value (F = [AgNO{sub 3}/CH{sub 2}CH(CN)], which was the molar ratio of the salt to the PAN repeat unit) of the PAN/3 wt.% o-MMT/Ag nanocomposites corresponded to larger average particle size and more AgNPs in the 2 wt.% AgNPs solution. The bactericidal property of AgNPs solution, which was obtained by soaking PAN/o-MMT/Ag nanocomposite films in distilled water, was evaluated by the paper disc diffusion method. The results revealed that the AgNPs solution did not inhibit the growth of filamentous fungi but was quite effective against tiny bacteria of Gram (+) Staphylococcus aureus, Gram (-) Escherichia coli and Klebsiella pneumonia. In particular, using a 2 wt.% AgNP solution that was obtained by soaking PAN/3 wt.% o-MMT/Ag nanocomposite (F = 0.20) for 24 h in distilled water showed the most effectively inhibited growth of bacteria (16.4 mm). Its antibacterial activity still remained, yielding an inhibition zone

  15. High pressure measurement of the uniaxial stress of host layers on intercalants and staging transformation of intercalation compounds

    CERN Document Server

    Park, T R; Kim, H; Min, P

    2002-01-01

    A layered double-hydroxide intercalation compound was synthesized to measure the uniaxial stress the host layers exert on the intercalants. To measure the uniaxial stress, we employed the photoluminescence (PL) from the intercalated species, the Sm ion complex, as it is sensitive to the deformation of the intercalants. Of the many PL peaks the Sm ion complex produces, the one that is independent of the counter-cation environment was chosen for the measurement since the Sm ion complexes are placed under a different electrostatic environment after intercalation. The peak position of the PL was redshifted linearly with increasing hydrostatic pressure on the intercalated sample. Using this pressure-induced redshifting rate and the PL difference at ambient pressure between the pre-intercalation and the intercalated ions, we found that, in the absence of external pressure, the uniaxial stress exerted on the samarium ion complexes by the host layers was about 13.9 GPa at room temperature. Time-resolved PL data also ...

  16. Spectroscopic study for a chromium-adsorbed montmorillonite

    Science.gov (United States)

    Nurtay, Maidina ·; Tuersun, Maierdan ·; Cai, Yuanfeng; Açıkgöz, Muhammed; Wang, Hongtao; Pan, Yuguan; Zhang, Xiaoke; Ma, Xiaomei

    2017-02-01

    Samples of purified montmorillonite with trace amounts of quartz were subjected to different concentrations of chromium sulphate solutions for one week to allow cation exchange. The chromium-bearing montmorillonites were verified and tested using powder X-ray diffractometry (XRD), X-ray fluorescence spectrometry, electron spin resonance (ESR) spectrometry and Fourier transformation infrared (FTIR) spectroscopy to explore the occupation sites of the chromium. The ESR spectra recorded before and after the chromium exchange show clear differences: a strong and broad resonance with two shoulders at the lower magnetic field side was present to start, and its intensity as well as that of the ferric iron resonance, increased with the concentration of added chromium. The signals introduced by the chromium, for example at g = 1.975 and 2.510 etc., suggested that the chromium had several occupational sites. The ESR peak with g = 2.510 in the second derivative spectrum suggested that Cr3+ was weakly bounded to TOT with the form of [Cr(H2O)3]3+ in hexagonal cavities. This was verified by comparing the FTIR spectra of the pure and modified montmorillonite. The main resonance centred at g = 1.975 indicated that the majority of Cr3+ occupied the interlayer region as [Cr(H2O)6]3+. The substitution of Ca2 + by Cr3+ also greatly affected the vibration of the hydrogens associate to water, ranged from 3500 to 2600 cm-1 in FTIR. Furthermore, the presence of two diffraction lines in the XRD results (specifically those with d-values of 1.5171 and 1.2673 nm) and the calculations of the size of the interlayer space suggested the presence of two types of montmorillonite with different hydration cations in the sample exposed to 0.2 M chromium sulphate. The two diffraction lines were assigned to [Cr(H2O)6]3+ and [Cr(H2O)3O3]3+, respectively. This also suggested that the species of hydration cation was constrained by the concentration of the chromium solution.

  17. Heavy Metal Removal from Water by Adsorption Using Pillared Montmorillonite

    Institute of Scientific and Technical Information of China (English)

    LIU Yun; WU Pingxiao; DANG Zhi; YE Daiqi

    2006-01-01

    Removal of Cu2+, Cr3+ and Cd2+ from aqueous solutions by adsorption on montmorillonite modified by sodium dodecylsulfate (SDS) and hydroxy-alumino-silicate (HAS) was investigated.Experiments were carried out as a function of solution pH, solute concentration, and time. The Langmuir model was adopted to describe the single-solute adsorption isotherm, in which the Langmuir parameters were directly taken from those obtained in single-solute systems. The kinetics of metal ions adsorption was examined and the pseudo-first-order rate constant was finally evaluated.

  18. The growth of carbon nanotubes on montmorillonite and zeolite (clinoptilolite)

    Energy Technology Data Exchange (ETDEWEB)

    Kadlecikova, M. [Department of Microelectronics, Faculty of Electrical Engineering and Information Technology, Slovak University of Technology, Ilkovicova 3, 812 19 Bratislava (Slovakia); Breza, J. [Department of Microelectronics, Faculty of Electrical Engineering and Information Technology, Slovak University of Technology, Ilkovicova 3, 812 19 Bratislava (Slovakia)], E-mail: juraj.breza@stuba.sk; Jesenak, K.; Pastorkova, K.; Luptakova, V. [Department of Inorganic Chemistry, Faculty of Natural Sciences, Comenius University, Mlynska Dolina, 842 15 Bratislava (Slovakia); Kolmacka, M.; Vojackova, A. [Department of Microelectronics, Faculty of Electrical Engineering and Information Technology, Slovak University of Technology, Ilkovicova 3, 812 19 Bratislava (Slovakia); Michalka, M. [International Laser Centre, Ilkovicova 3, 812 19 Bratislava (Slovakia); Vavra, I. [Institute of Electrical Engineering, Slovak Academy of Sciences, Dubravska Cesta 9, 841 04 Bratislava (Slovakia); Krizanova, Z. [Department of Microelectronics, Faculty of Electrical Engineering and Information Technology, Slovak University of Technology, Ilkovicova 3, 812 19 Bratislava (Slovakia)

    2008-06-15

    Synthesis of carbon nanotubes described in the present work is based on activation of methane in a hot filament CVD reactor and subsequent creation of nanostructures on a catalyst pre-treated polished surface of silicon. An essential step of the synthesis is the use of natural minerals as catalysts. We have studied the catalyst parameters, the way of its application and the amount of Fe{sup 3+} cations on the surface of aluminosilicates on the quality of the grown nanotube layers. The growth of carbon nanotubes catalyzed by montmorillonite and zeolite (clinoptilolite) was confirmed by scanning electron microscopy and Raman spectroscopy.

  19. The growth of carbon nanotubes on montmorillonite and zeolite (clinoptilolite)

    Science.gov (United States)

    Kadlečíková, M.; Breza, J.; Jesenák, K.; Pastorková, K.; Luptáková, V.; Kolmačka, M.; Vojačková, A.; Michalka, M.; Vávra, I.; Križanová, Z.

    2008-06-01

    Synthesis of carbon nanotubes described in the present work is based on activation of methane in a hot filament CVD reactor and subsequent creation of nanostructures on a catalyst pre-treated polished surface of silicon. An essential step of the synthesis is the use of natural minerals as catalysts. We have studied the catalyst parameters, the way of its application and the amount of Fe 3+ cations on the surface of aluminosilicates on the quality of the grown nanotube layers. The growth of carbon nanotubes catalyzed by montmorillonite and zeolite (clinoptilolite) was confirmed by scanning electron microscopy and Raman spectroscopy.

  20. Intercalation and controlled release properties of vitamin C intercalated layered double hydroxide

    Science.gov (United States)

    Gao, Xiaorui; Lei, Lixu; O'Hare, Dermot; Xie, Juan; Gao, Pengran; Chang, Tao

    2013-07-01

    Two drug-inorganic composites involving vitamin C (VC) intercalated in Mg-Al and Mg-Fe layered double hydroxides (LDHs) have been synthesized by the calcination-rehydration (reconstruction) method. Powder X-ray diffraction (XRD), Fourier transform infrared (FTIR), and UV-vis absorption spectroscopy indicate a successful intercalation of VC into the interlayer galleries of the LDH host. Studies of VC release from the LDHs in deionised water and in aqueous CO32- solutions imply that Mg3Al-VC LDH is a better controlled release system than Mg3Fe-VC LDH. Analysis of the release profiles using a number of kinetic models suggests a solution-dependent release mechanism, and a diffusion-controlled deintercalation mechanism in deionised water, but an ion exchange process in CO32- solution.

  1. Interaction of nonionic surfactant AEO9 with ionic surfactants

    Institute of Scientific and Technical Information of China (English)

    ZHANG Zhi-guo; YIN Hong

    2005-01-01

    The interaction in two mixtures of a nonionic surfactant AEO9 (C12H25O(CH2CH2O)9H) and different ionic surfactants was investigated. The two mixtures were AEO9/sodium dodecyl sulfate (SDS) and AEO9/cetyltrimethylammonium bromide (CTAB) at molar fraction of AEO9, αAEO9 =0.5. The surface properties of the surfactants, critical micelle concentration (CMC),effectiveness of surface tension reduction (γCMC), maximum surface excess concentration (Гmax) and minimum area per molecule at the air/solution interface (Amin) were determined for both individual surfactants and their mixtures. The significant deviations from ideal behavior (attractive interactions) of the nonionic/ionic surfactant mixtures were determined. Mixtures of both AEO9/SDS and AEO9/CTAB exhibited synergism in surface tension reduction efficiency and mixed micelle formation, but neither exhibited synergism in surface tension reduction effectiveness.

  2. Efficient Removal of Co2+ from Aqueous Solution by 3-Aminopropyltriethoxysilane Functionalized Montmorillonite with Enhanced Adsorption Capacity.

    Directory of Open Access Journals (Sweden)

    Zhujian Huang

    Full Text Available To achieve a satisfactory removal efficiency of heavy metal ions from wastewater, silane-functionalized montmorillonite with abundant ligand-binding sites (-NH2 was synthesized as an efficient adsorbent. Ca-montmorillonite (Ca-Mt was functionalized with 3-aminopropyl triethoxysilane (APTES to obtain the APTES-Mt products (APTES1.0CEC-Mt, APTES2.0CEC-Mt, APTES3.0CEC-Mt, APTES4.0CEC-Mt with enhanced adsorption capacity for Co2+. The physico-chemical properties of the synthesized adsorbents were characterized by spectroscopic and microscopic methods, and the results demonstrated that APTES was successfully intercalated into the gallery of Ca-Mt or grafted onto the surface of Ca-Mt through Si-O bonds. The effect of solution pH, ionic strength, temperature, initial concentrations and contact time on adsorption of Co2+ by APTES-Mt was evaluated. The results indicated that adsorption of Co2+ onto Ca-Mt, APTES1.0CEC-Mt and APTES2.0CEC-Mt can be considered to be a pseudo-second-order process. In contrast, adsorption of Co2+ onto APTES3.0CEC-Mt and APTES4.0CEC-Mt fitted well with the pseudo-first-order kinetics. The adsorption isotherms were described by the Langmuir model, and the maximum adsorption capacities of APTES1.0CEC-Mt, APTES2.0CEC-Mt, APTES3.0CEC-Mt and APTES4.0CEC-Mt were 25.1, 33.8, 61.6, and 61.9 mg·g-1, respectively. In addition, reaction temperature had no impact on the adsorption capacity, while both the pH and ionic strength significantly affected the adsorption process. A synergistic effect of ion exchange and coordination interactions on adsorption was observed, thereby leading to a significant enhancement of Co2+ adsorption by the composites. Thus, APTES-Mt could be a cost-effective and environmental-friendly adsorbent, with potential for treating Co2+-rich wastewater.

  3. Efficient Removal of Co2+ from Aqueous Solution by 3-Aminopropyltriethoxysilane Functionalized Montmorillonite with Enhanced Adsorption Capacity.

    Science.gov (United States)

    Huang, Zhujian; Wu, Pingxiao; Gong, Beini; Dai, Yaping; Chiang, Pen-Chi; Lai, Xiaolin; Yu, Guangwei

    2016-01-01

    To achieve a satisfactory removal efficiency of heavy metal ions from wastewater, silane-functionalized montmorillonite with abundant ligand-binding sites (-NH2) was synthesized as an efficient adsorbent. Ca-montmorillonite (Ca-Mt) was functionalized with 3-aminopropyl triethoxysilane (APTES) to obtain the APTES-Mt products (APTES1.0CEC-Mt, APTES2.0CEC-Mt, APTES3.0CEC-Mt, APTES4.0CEC-Mt) with enhanced adsorption capacity for Co2+. The physico-chemical properties of the synthesized adsorbents were characterized by spectroscopic and microscopic methods, and the results demonstrated that APTES was successfully intercalated into the gallery of Ca-Mt or grafted onto the surface of Ca-Mt through Si-O bonds. The effect of solution pH, ionic strength, temperature, initial concentrations and contact time on adsorption of Co2+ by APTES-Mt was evaluated. The results indicated that adsorption of Co2+ onto Ca-Mt, APTES1.0CEC-Mt and APTES2.0CEC-Mt can be considered to be a pseudo-second-order process. In contrast, adsorption of Co2+ onto APTES3.0CEC-Mt and APTES4.0CEC-Mt fitted well with the pseudo-first-order kinetics. The adsorption isotherms were described by the Langmuir model, and the maximum adsorption capacities of APTES1.0CEC-Mt, APTES2.0CEC-Mt, APTES3.0CEC-Mt and APTES4.0CEC-Mt were 25.1, 33.8, 61.6, and 61.9 mg·g-1, respectively. In addition, reaction temperature had no impact on the adsorption capacity, while both the pH and ionic strength significantly affected the adsorption process. A synergistic effect of ion exchange and coordination interactions on adsorption was observed, thereby leading to a significant enhancement of Co2+ adsorption by the composites. Thus, APTES-Mt could be a cost-effective and environmental-friendly adsorbent, with potential for treating Co2+-rich wastewater.

  4. Intercalation compounds involving inorganic layered structures

    Directory of Open Access Journals (Sweden)

    CONSTANTINO VERA R. L.

    2000-01-01

    Full Text Available Two-dimensional inorganic networks can shown intracrystalline reactivity, i.e., simple ions, large species as Keggin ions, organic species, coordination compounds or organometallics can be incorporated in the interlayer region. The host-guest interaction usually causes changes in their chemical, catalytic, electronic and optical properties. The isolation of materials with interesting properties and making use of soft chemistry routes have given rise the possibility of industrial and technological applications of these compounds. We have been using several synthetic approaches to intercalate porphyrins and phthalocyanines into inorganic materials: smectite clays, layered double hydroxides and layered niobates. The isolated materials have been characterized by elemental and thermal analysis, X-ray diffraction, surface area measurements, scanning electronic microscopy, electronic and resonance Raman spectroscopies and EPR. The degree of layer stacking and the charge density of the matrices as well their acid-base nature were considered in our studies on the interaction between the macrocycles and inorganic hosts.

  5. Selective intercalation of polymers in carbon nanotubes.

    Science.gov (United States)

    Bazilevsky, Alexander V; Sun, Kexia; Yarin, Alexander L; Megaridis, Constantine M

    2007-07-03

    A room-temperature, open-air method is devised to selectively intercalate relatively low-molecular-weight polymers (approximately 10-100 kDa) from dilute, volatile solutions into open-end, as-grown, wettable carbon nanotubes with 50-100 nm diameters. The method relies on a novel self-sustained diffusion mechanism driving polymers from dilute volatile solutions into carbon nanotubes and concentrating them there. Relatively low-molecular-weight polymers, such as poly(ethylene oxide) (PEO, 600 kDa) and poly(caprolactone) (PCL, 80 kDa), were encapsulated in graphitic nanotubes as confirmed by transmission electron microscopy, which revealed morphologies characteristic of mixtures in nanoconfinements affected by intermolecular forces. Whereas relatively small, flexible polymer molecules can conform to enter these nanotubes, larger macromolecules (approximately 1000 kDa) remain outside. The selective nature of this process is useful for filling nanotubes with polymers and could also be valuable in capping nanotubes.

  6. Topotactic exchange and intercalation of calcium phosphate

    Science.gov (United States)

    Lima, Cicero B. A.; Airoldi, Claudio

    2004-11-01

    The precursor (NH 4) 2Ca(H 2PO 4) 2ṡH 2O (CaAP) compound was obtained by combining a calcium chloride solution with dibasic ammonium phosphate. After submitting it to a thermal treatment, crystalline calcium phosphate, Ca(H 2PO 4) 2ṡH 2O (CaP) was isolated. X-ray diffraction patterns for this compound indicated good crystallinity, with a peak at 2θ=12.8°, to give an interlamellar distance of 697 pm, which changed to 1550 pm, when the reaction employed phenylphosphonic acid, and to 1514 pm when intercalated with methylamine. Phosphorus and calcium analysis from colorimetric and gravimetric methods gave for CaP 24.2 and 15.8%, respectively, to yield a P:Ca molar ratio equal to two. The phosphorus nuclear magnetic resonance presented a peak centered at -1.23 ppm, in agreement with the existence of phosphate groups in protonated form. CaAP showed a mass loss of 21.2% in the 466 to 541 K interval due to ammonia and water elimination to yield Ca(PO 3) 3, and CaP can be dehydrated at 440 K for 6 h. A topotactical exchange occurred when CaP is intercalated with methylamine or reacted with phenylphosphonic acid to yield the phosphonate compound and the infrared spectrum of the resulting compound clearly showed the presence of PO 4 and PO 3 groups. The topotactic exchange was also demonstrated by X-ray diffractometry in following the stages of decomposition from 527 to 973 K.

  7. Computer simulation of alkali metal cation-montmorillonite hydrates

    Energy Technology Data Exchange (ETDEWEB)

    Chang, Fang-Ru Chou [Columbia Univ., Palisades, NY (United States); Skipper, N.T. [Univ. College, London (United Kingdom); Sposito, G. [Lawrence Berkeley National Lab., CA (United States)

    1997-12-31

    Molecular structure in the interlayers of Li-, Na-, or K-Wyoming montmorillonite with one, two, or three adsorbed water layers was investigated for the first time by concurrent Monte Carlo and molecular dynamics (MD) simulation, based on the Matsouka-Clementi-Yoshimine, (MCY) model of water-water interactions. Calculated layer spacings, as well as interlayer-species self-diffusion coefficients, were in good agreement with available experimental data. Inner-sphere surface complexes of the cations with tetrahedral charge sites were observed for all hydrates, whereas outer-sphere surface complexes of the cations with octahedral charge sites, found also in the one-layer hydrate, tended to dissociate from the clay mineral basal planes into a diffuse layer in the two- and three-layer hydrates. Differences in the interlayer water structure among the hydrates mainly reflected cation solvation, although some water molecules were entrapped within cavities in the montmorillonite surface. All of the interlayer cation and water species exchanged on the time scale (0.2 ns) of the MD simulations. Comparisons with results obtained using, instead of the MCY model, the TIP4P model for water-water, cation-water, and cation-clay interactions indicated that layer spacings and interlayer species mobilities tend to be under-predicted by the TIP4P model.

  8. Synthesis and characterization of Mn intercalated Mg-Al hydrotalcite.

    Science.gov (United States)

    Yang, Chengxue; Liao, Libing; Lv, Guocheng; Wu, Limei; Mei, Lefu; Li, Zhaohui

    2016-10-01

    Mn intercalated hydrotalcite was prepared using a reconstruction method. And Mn intercalation was confirmed by XRD, FTIR, and thermal analyses. The different valences of Mn were present as determined by XPS. Calcination slightly promoted the isomorphic replacement of Mn(2+) and Mn(3+) for Mg(2+) and Al(3+), especially the replacement of Mn(2+) for Mg(2+) and Al(3+), and to some extent, reduced Mn intercalation. Ultrasonic treatment significantly increased Mn intercalation in permanganate form (Mn(7+)), and promoted the replacement of Mn(2+) for Mg(2+) and Al(3+). XRF analysis showed that ultrasonic treatment decreased the unbalanced layer charge of Mn intercalated hydrotalcite, while prolonged calcination increased it. These results may provide guidance on the preparation and application of Mn intercalated hydrotalcite. Extended calcination time and ultrasonic vibration increased the interlayer spacing of hydrotalcite, as a result of reduction in layer charge. As the layer charge was not completely balanced after Mn intercalation, a certain amount of CO3(2-) was re-adsorbed into the interlayer space. Mn-hydrotalcites with different layer charges, different contents of Mn with varying valences are expected to have different performances in the process of adsorption, degradation, and catalysis.

  9. Chronopotentiometric study of intercalation of layered III-VI semiconductors

    Energy Technology Data Exchange (ETDEWEB)

    Bakhmatyuk, B.P.; Grigorchak, I.I.; Kaminskii, V.M.; Kovalyuk, Z.D.; Yurtsenyuk, S.P.

    1985-04-01

    The known group of materials open to intercalation (i.e., the incorporation of foreign ions, atoms, or molecules into the space between layers of layered crystals) has recently been enlarged by the layered semiconducting monochalcogenides of indium and gallium. This article is concerned with an electrochemical investigation of their intercalation process. The chronopotentiograms for the reduction and oxidation of electrodes made of the layered monoselenides of indium and gallium in 1 M lithium perchlorate solution in propylene carbonate were examined. The electrodes studied were examined by x-rays before and after intercalation. It is indicated that the intercalation of InSe and GaSe with lithium yields nonstoichiometric phases in the range of 0 is less than x is less than or equal to 1. Using the equilibrium potentials of the intercalated phases and known relations, the free energies of these compounds and of their formation can be determined. The electrochemical intercalation leads to the formation of ternary compounds Li /SUB x/ InSe and Li /SUB x/ GaSe. The free energies of formation of these compounds increase with increasing degree of reduction of the compounds. The intercalation of indium and gallium monoselenide with lithium can be regarded as reversible.

  10. ADSORPTION OF SURFACTANT ON CLAYS

    Science.gov (United States)

    Surfactants used to enhance remediation of soils by soil washing are often lost in the process. Neither the amount nor the cause of this loss is known. It is assumed that clays present in the soil are responsible for the loss of the surfactant. In this papere, adsorption prope...

  11. Surfactant monitoring by foam generation

    Science.gov (United States)

    Mullen, Ken I.

    1997-01-01

    A device for monitoring the presence or absence of active surfactant or other surface active agents in a solution or flowing stream based on the formation of foam or bubbles is presented. The device detects the formation of foam with a light beam or conductivity measurement. The height or density of the foam can be correlated to the concentration of the active surfactant present.

  12. Surfactant adsorption kinetics in microfluidics

    Science.gov (United States)

    Riechers, Birte; Maes, Florine; Akoury, Elias; Semin, Benoît; Gruner, Philipp; Baret, Jean-Christophe

    2016-10-01

    Emulsions are metastable dispersions. Their lifetimes are directly related to the dynamics of surfactants. We design a microfluidic method to measure the kinetics of adsorption of surfactants to the droplet interface, a key process involved in foaming, emulsification, and droplet coarsening. The method is based on the pH decay in the droplet as a direct measurement of the adsorption of a carboxylic acid surfactant to the interface. From the kinetic measurement of the bulk equilibration of the pH, we fully determine the adsorption process of the surfactant. The small droplet size and the convection during the droplet flow ensure that the transport of surfactant through the bulk is not limiting the kinetics of adsorption. To validate our measurements, we show that the adsorption process determines the timescale required to stabilize droplets against coalescence, and we show that the interface should be covered at more than 90% to prevent coalescence. We therefore quantitatively link the process of adsorption/desorption, the stabilization of emulsions, and the kinetics of solute partitioning—here through ion exchange—unraveling the timescales governing these processes. Our method can be further generalized to other surfactants, including nonionic surfactants, by making use of fluorophore-surfactant interactions.

  13. Plutonium(IV) sorption to montmorillonite in the presence of organic matter.

    Science.gov (United States)

    Boggs, Mark A; Dai, Zurong; Kersting, Annie B; Zavarin, Mavrik

    2015-03-01

    The effect of altering the order of addition in a ternary system of plutonium(IV), organic matter (fulvic acid, humic acid and desferrioxamine B), and montmorillonite was investigated. A decrease in Pu(IV) sorption to montmorillonite in the presence of fulvic and humic acid relative to the binary Pu-montmorillonite system, is attributed to strong organic aqueous complex formation with aqueous Pu(IV). No dependence on the order of addition was observed. In contrast, in the system where Pu(IV) was equilibrated with desferrioxamine B (DFOB) prior to addition of montmorillonite, an increase in Pu(IV) sorption was observed relative to the binary system. When DFOB was equilibrated with montmorillonite prior to addition of Pu(IV), Pu(IV) sorption was equivalent to the binary system. X-ray diffraction and transmission electron microscopy revealed that DFOB accumulated in the interlayer of montmorillonite. The order of DFOB addition plays an important role in the observed sorption/desorption behavior of Pu. The irreversible nature of DFOB accumulation in the montmorillonite interlayer leads to an apparent dependence of Pu sorption on the order of addition in the ternary system. This work demonstrates that the order of addition will be relevant in ternary systems in which at least one component exhibits irreversible sorption behavior.

  14. Montmorillonite enhanced ciprofloxacin transport in saturated porous media with sorbed ciprofloxacin showing antibiotic activity

    Science.gov (United States)

    Chen, Hao; Gao, Bin; Yang, Liu-Yan; Ma, Lena Q.

    2015-02-01

    Antibiotic ciprofloxacin (CIP) is immobile in the subsurface but it has been frequently detected in the aquatic system. Therefore it is important to investigate the factors impacting CIP's mobilization in aquifer. Laboratory columns packed with sand were used to test colloid-facilitated CIP transport by 1) using kaolinite or montmorillonite to mobilize presorbed-CIP in a column or 2) co-transporting with CIP by pre-mixing them before transport. The Langmuir model showed that CIP sorption by montmorillonite (23 g kg- 1) was 100 times more effective than sand or kaolinite. Even with strong CIP complexation ability to Fe/Al coating on sand surface, montmorillonite promoted CIP transport, but not kaolinite. All presorbed-CIP by sand was mobilized by montmorillonite after 3 pore volumes through co-transporting of CIP with montmorillonite. The majority of CIP was fixed onto the montmorillonite interlayer but still showed inhibition of bacteria growth. Our results suggested that montmorillonite with high CIP sorption ability can act as a carrier to enhance CIP's mobility in aquifer.

  15. Electrochemical synthesis of alkali-intercalated iron selenide superconductors

    Institute of Scientific and Technical Information of China (English)

    申士杰; 应天平; 王刚; 金士锋; 张韩; 林志萍; 陈小龙

    2015-01-01

    Electrochemical method has been used to insert K/Na into FeSe lattice to prepare alkali-intercalated iron selenides at room temperature. Magnetization measurement reveals that KxFe2Se2 and NaxFe2Se2 are superconductive at 31 K and 46 K, respectively. This is the first successful report of obtaining metal-intercalated FeSe-based high-temperature superconductors using electrochemical method. It provides an effective route to synthesize metal-intercalated layered compounds for new superconductor exploration.

  16. Prediction of superconductivity in Li-intercalated bilayer phosphorene

    Energy Technology Data Exchange (ETDEWEB)

    Huang, G. Q. [Department of Physics, Nanjing Normal University, Nanjing 210023 (China); National Laboratory of Solid State Microstructures, Nanjing University, Nanjing 210093 (China); Xing, Z. W., E-mail: zwxing@nju.edu.cn [National Laboratory of Solid State Microstructures, Nanjing University, Nanjing 210093 (China); Synergetic Innovation Center of Quantum Information and Quantum Physics, University of Science and Technology of China, Hefei, Anhui 230026 (China); Xing, D. Y. [National Laboratory of Solid State Microstructures, Nanjing University, Nanjing 210093 (China); Collaborative Innovation Center of Advanced Microstructures and Department of Physics, Nanjing University, Nanjing 210093 (China)

    2015-03-16

    It is shown that bilayer phosphorene can be transformed from a direct-gap semiconductor to a BCS superconductor by intercalating Li atoms. For the Li-intercalated bilayer phosphorene, we find that the electron occupation of Li-derived band is small and superconductivity is intrinsic. With increasing the intercalation of Li atoms, both increased metallicity and strong electron-phonon coupling are favorable for the enhancement of superconductivity. The obtained electron-phonon coupling λ can be larger than 1 and the superconducting temperature T{sub c} can be increased up to 16.5 K, suggesting that phosphorene may be a good candidate for a nanoscale superconductor.

  17. Amine-intercalated α-zirconium phosphates as lubricant additives

    Energy Technology Data Exchange (ETDEWEB)

    Xiao, Huaping; Dai, Wei [Department of Mechanical Engineering, Texas A& M University, College Station, TX 77843 (United States); Kan, Yuwei; Clearfield, Abraham [Department of Chemistry, Texas A& M University, College Station, TX 77843 (United States); Liang, Hong, E-mail: hliang@tamu.edu [Department of Mechanical Engineering, Texas A& M University, College Station, TX 77843 (United States)

    2015-02-28

    In this study, three types of amines intercalated α-zirconium phosphate nanosheets with different interspaces were synthesized and examined as lubricant additives to a mineral oil. Results from tribological experiments illustrated that these additives improved lubricating performance. Results of rheological experiments showed that the viscosity of the mineral oil was effectively reduced with the addition of α-zirconium phosphate nanosheets. The two-dimensional structure, with larger interspaces, resulting from amine intercalation, exhibited improved effectiveness in reducing viscosity. This study demonstrates that the nanosheet structure of α-zirconium phosphates is effective in friction reduction. The manufacture of lubricants with tailored viscosity is possible by using different intercalators.

  18. n-Pentylamine-intercalated layered perovskite-type oxide

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    A novel n-pentylamine-intercalated layered perovskite-type oxide,C5H11NH3-Sr2Nb3O10, was prepared and characterized by using XRD, FT-IR, Raman spectrascopy, and elemental analysis. It was shown that the intercalated n-pentylamine adopted a bilayer formation with some overlap and tilt, and the lattice of the perovskite layer was distorted due to the intercalation of n-pentylamine. The as-prepared sample gave clear electric hysteresis loop and did not show fatigue after 1011 switching circles, and therefore, could be considered as a new kind of fatigue-free ferroelectric materials.

  19. Electrochemical Intercalation of Sodium into Silicon Thin Film

    Institute of Scientific and Technical Information of China (English)

    Dong-Yeon Kim; Hyo-Jun Ahn; Gyu-Bong Cho; Jong-Seon Kim; Ho-Suk Ryu; Ki-Won Kim; Jou-Hyeon Ahn; Won-Cheol Shin

    2008-01-01

    In order to investigate the possibility of Si thin film as an anode for Na battery, we studied the electrochemical intercalation of sodium into the Si film. Amorphous Si thin film electrode was prepared using DC magnetron sputtering. Sodium ion could intercalate into Si thin film upto Na0.52Si, i.e. 530mAh · g-1-Si. The first discharge capacity was 80mAh.·g-1-Si, which meant reversible amount of sodium intercalation. The discharge capacity slightly decreased to 70mAh · g-1-Si after 10 cycles.

  20. Strain Lattice Imprinting in Graphene by C60 Intercalation at the Graphene/Cu Interface

    NARCIS (Netherlands)

    Monazami, Ehsan; Bignardi, Luca; Rudolf, Petra; Reinke, Petra

    2015-01-01

    Intercalation of C60 molecules at the graphene-substrate interface by annealing leads to amorphous and crystalline intercalated structures. A comparison of topography and electronic structure with wrinkles and moiré patterns confirms intercalation. The intercalated molecules imprint a local strain/d

  1. Strain Lattice Imprinting in Graphene by C60 Intercalation at the Graphene/Cu Interface

    NARCIS (Netherlands)

    Monazami, Ehsan; Bignardi, Luca; Rudolf, Petra; Reinke, Petra

    2015-01-01

    Intercalation of C60 molecules at the graphene-substrate interface by annealing leads to amorphous and crystalline intercalated structures. A comparison of topography and electronic structure with wrinkles and moiré patterns confirms intercalation. The intercalated molecules imprint a local strain/d

  2. Strain Lattice Imprinting in Graphene by C60 Intercalation at the Graphene/Cu Interface

    NARCIS (Netherlands)

    Monazami, Ehsan; Bignardi, Luca; Rudolf, Petra; Reinke, Petra

    2015-01-01

    Intercalation of C60 molecules at the graphene-substrate interface by annealing leads to amorphous and crystalline intercalated structures. A comparison of topography and electronic structure with wrinkles and moiré patterns confirms intercalation. The intercalated molecules imprint a local

  3. Determining the cation exchange capacity of montmorillonite by simultaneous thermal analysis method

    Science.gov (United States)

    Boeva, N. M.; Bocharnikova, Yu. I.; Belousov, P. E.; Zhigarev, V. V.

    2016-08-01

    A way of determining the cation exchange capacity of montmorillonite by simultaneous thermal analysis is developed using as an example the bentonites of the 10th Khutor deposit (Republic of Khakassia) and the Vodopadnyi area (Sakhalin Island). A correlation is established between the cation exchange capacity of smectite and its weight loss upon heating in the range of dehydration; the enthalpy of dehydration of montmorillonite; and the weight loss and the enthalpy of thermal dissociation of ethylene glycol contained in the interlayer space of the mineral's crystal structure. These data open up new possibilities for determining the cation exchange capacity of montmorillonite, the most important technological indicator of the natural clay nanomineral.

  4. Innovation in surfactant therapy II: surfactant administration by aerosolization.

    Science.gov (United States)

    Pillow, J Jane; Minocchieri, S

    2012-01-01

    Instilled bolus surfactant is the only approved surfactant treatment for neonatal respiratory distress syndrome. However, recent trends towards increased utilization of noninvasive respiratory support for preterm infants with surfactant deficiency have created a demand for a similarly noninvasive means of administering exogenous surfactant. Past approaches to surfactant nebulization met with varying success due to inefficient aerosol devices resulting in low intrapulmonary delivery doses of surfactant with variable clinical effectiveness. The recent development of vibrating membrane nebulizers, coupled with appropriate positioning of the interface device, indicates that efficient delivery of aerosolized surfactant is now a realistic goal in infants. Evidence of clinical effect despite low total administered dose in pilot studies, together with suggestions of enhanced homogeneity of pulmonary distribution indicate that this therapy may be applied in a cost-effective manner, with minimal patient handling and disruption. These studies need to be subjected to appropriately designed randomized controlled trials. Further work is also required to determine the optimum delivery route (mask, intranasal prong, nasopharyngeal or laryngeal), dosing amount and redosing interval.

  5. Interaction of nonionic surfactant AEO9 with ionic surfactants*

    OpenAIRE

    2005-01-01

    The interaction in two mixtures of a nonionic surfactant AEO9 (C12H25O(CH2CH2O)9H) and different ionic surfactants was investigated. The two mixtures were AEO9/sodium dodecyl sulfate (SDS) and AEO9/cetyltrimethylammonium bromide (CTAB) at molar fraction of AEO9, α AEO9=0.5. The surface properties of the surfactants, critical micelle concentration (CMC), effectiveness of surface tension reduction (γ CMC), maximum surface excess concentration (Γ max) and minimum area per...

  6. Sorption of a nonionic surfactant Tween 80 by minerals and soils

    Energy Technology Data Exchange (ETDEWEB)

    Kang, Soyoung, E-mail: soyoung@pusan.ac.kr; Jeong, Hoon Young, E-mail: hjeong@pusan.ac.kr

    2015-03-02

    Highlights: • Tween 80 sorption varies significantly among soil minerals. • Sorption mechanisms and atomic compositions explain to mineral-specific sorption. • Clay minerals and SOM in soils are the key contributors to Tween 80 sorption. • Hysteresis suggests the potential difficulty in removing residual surfactants. - Abstract: Batch experiments were conducted to evaluate Tween 80 sorption by oxides, aluminosilicates, and soils. For oxides, the sorption by silica and alumina follow linear isotherms, and that by hematite follows a Langmuir isotherm. Considering isotherm type and surface coverage, Tween 80 may partition into the silica/alumina–water interface, whereas it may bind to hematite surface sites. Among aluminosilicates, montmorillonite shows the greatest sorption due to the absorption of Tween 80 into interlayers. For other aluminosilicates, it sorbs to surfaces, with the sorption increasing as plagioclase < vermiculite < kaolinite. This results from the relative reactivity among surface sites: ≡NaOH, ≡CaOH << ≡SiOH < ≡AlOH. Experiments using dry- and wet-sieved soils reveal that fine-grained clay minerals, difficult to separate by dry-sieving, contribute significantly to Tween 80 sorption. The greater sorption by untreated soils than H{sub 2}O{sub 2}-treated soils indicates that soil organic matter is a vital sorbent. The sorption hysteresis, contributed to by clay minerals and soil organic matter, is characterized by the greater sorption during the desorption than the sorption stages. This suggests the potential difficulty in removing surfactants from soils. Also, sorption of surfactants can adversely affect surfactant-enhanced remediation by decreasing the aquifer permeability and the availability of surfactants for micellar solubilization.

  7. Electronic spectra of anions intercalated in layered double hydroxides

    Indian Academy of Sciences (India)

    S Radha; P Vishnu Kamath

    2013-10-01

    Transition metal complexes intercalated in layered double hydroxides have a different electronic structure as compared to their free state owing to their confinement within the interlayer gallery. UV–Vis absorptions of the intercalated complex anions show a significant shift as compared to their free state. The ligand to metal charge transfer transitions of the ferricyanide anion show a red shift on intercalation. The ferrocyanide ion shows a significant blue shift of – bands due to the increased separation between 2g and g levels on intercalation. MnO$^{-}_{4}$ ion shows a blue shift in its ligand to metal charge transfer transition since the non-bonding 1 level of oxygen from which the transition arises is stabilized.

  8. Intercalation and Stability of Layered Semiconductive Material in Corrosive Environment

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    The intercalation of 4-methyl pyridine (4-picoline) into layered semiconductive material (MnPS3) and the stability of the resulting materials in corrosive environments (water, HCI and open atmosphere) were investigated.Powder X-ray diffraction (XRD) indicated that the presence of water and hydrochloric acid greatly influenced the existing form of intercalation and its orientation in the interlayer of the host. Atmospheric environment (open air) affected the guest orientation in the interlayer of the host material. Phase transformation occurred and the material was stable. The intercalated compounds could be indexed in the trigonal unit cell. The XRD patterns exhibited sharp hkl reflections of the intercalated compounds, which formed in water and HCI,confirming that the materials were well crystalline and stable in corrosive environments.

  9. Intercalation of Carbon Nanotube Fibers to Improve their Conductivity Project

    Data.gov (United States)

    National Aeronautics and Space Administration — This proposed research will explore how NASA intercalation technology can be used to lower the resistivity of the new Rice-Teijin fiber make them viable for NASA...

  10. Lithium isotope effect accompanying electrochemical intercalation of lithium into graphite

    CERN Document Server

    Yanase, S; Oi, T

    2003-01-01

    Lithium has been electrochemically intercalated from a 1:2 (v/v) mixed solution of ethylene carbonate (EC) and methylethyl carbonate (MEC) containing 1 M LiClO sub 4 into graphite, and the lithium isotope fractionation accompanying the intercalation was observed. The lighter isotope was preferentially fractionated into graphite. The single-stage lithium isotope separation factor ranged from 1.007 to 1.025 at 25 C and depended little on the mole ratio of lithium to carbon of the lithium-graphite intercalation compounds (Li-GIC) formed. The separation factor increased with the relative content of lithium. This dependence seems consistent with the existence of an equilibrium isotope effect between the solvated lithium ion in the EC/MEC electrolyte solution and the lithium in graphite, and with the formation of a solid electrolyte interfaces on graphite at the early stage of intercalation. (orig.)

  11. Desorption of plutonium from montmorillonite: An experimental and modeling study

    Science.gov (United States)

    Begg, James D.; Zavarin, Mavrik; Kersting, Annie B.

    2017-01-01

    Desorption of plutonium (Pu) will likely control the extent to which it is transported by mineral colloids. We evaluated the adsorption/desorption behavior of Pu on SWy-1 montmorillonite colloids at pH 4, pH 6, and pH 8 using batch adsorption and flow cell desorption experiments. After 21 days adsorption, Pu(IV) affinity for montmorillonite displayed a pH dependency, with Kd values highest at pH 4 and lowest at pH 8. The pH 8 experiment was further allowed to equilibrate for 6 months and showed an increase in Kd, indicating that true sorption equilibrium was not achieved within the first 21 days. For the desorption experiments, aliquots of the sorption suspensions were placed in a flow cell, and Pu-free solutions were then pumped through the cell for a period of 12 days. Changes in influent solution flow rate were used to investigate the kinetics of Pu desorption and demonstrated that it was rate-limited over the experimental timescales. At the end of the 12-day flow cell experiments, the extent of desorption was again pH dependent, with pH 8 > pH 6 > pH 4. Further, at pH 8, less Pu was desorbed after an adsorption contact time of 6 months than after a contact time of 21 days, consistent with an aging of Pu on the clay surface. A conceptual model for Pu adsorption/desorption that incorporated known surface-mediated Pu redox reactions was used to fit the experimental data. The resulting rate constants indicated processes occurring on timescales of months and even years which may, in part, explain observations of clay colloid-facilitated Pu transport on decadal timescales. Importantly, however, our results also imply that migration of Pu adsorbed to montmorillonite colloids at long (50-100 year) timescales under oxic conditions may not be possible without considering additional phenomena, such as co-precipitation.

  12. Surfactant enhanced volumetric sweep efficiency

    Energy Technology Data Exchange (ETDEWEB)

    Harwell, J.H.; Scamehorn, J.F.

    1989-10-01

    Surfactant-enhanced waterflooding is a novel EOR method aimed to improve the volumetric sweep efficiencies in reservoirs. The technique depends upon the ability to induce phase changes in surfactant solutions by mixing with surfactants of opposite charge or with salts of appropriate type. One surfactant or salt solution is injected into the reservoir. It is followed later by injection of another surfactant or salt solution. The sequence of injections is arranged so that the two solutions do not mix until they are into the permeable regions well away from the well bore. When they mix at this point, by design they form a precipitate or gel-like coacervate phase, plugging this permeable region, forcing flow through less permeable regions of the reservoir, improving sweep efficiency. The selectivity of the plugging process is demonstrated by achieving permeability reductions in the high permeable regions of Berea sandstone cores. Strategies were set to obtain a better control over the plug placement and the stability of plugs. A numerical simulator has been developed to investigate the potential increases in oil production of model systems. Furthermore, the hardness tolerance of anionic surfactant solutions is shown to be enhanced by addition of monovalent electrolyte or nonionic surfactants. 34 refs., 32 figs., 8 tabs.

  13. MICROBIAL SURFACTANTS IN ENVIRONMENTAL TECHNOLOGIES

    Directory of Open Access Journals (Sweden)

    T. P. Pirog

    2015-08-01

    Full Text Available It was shown literature and own experimental data concerning the use of microbial surface active glycolipids (rhamno-, sophoro- and trehalose lipids and lipopeptides for water and soil purification from oil and other hydrocarbons, removing toxic heavy metals (Cu2+, Cd2+, Ni2+, Pb2+, degradation of complex pollution (oil and other hydrocarbons with heavy metals, and the role of microbial surfactants in phytoremediation processes. The factors that limit the use of microbial surfactants in environmental technologies are discussed. Thus, at certain concentrations biosurfactant can exhibit antimicrobial properties and inhibit microorganisms destructing xenobiotics. Microbial biodegradability of surfactants may also reduce the effectiveness of bioremediation. Development of effective technologies using microbial surfactants should include the following steps: monitoring of contaminated sites to determine the nature of pollution and analysis of the autochthonous microbiota; determining the mode of surfactant introduction (exogenous addition of stimulation of surfactant synthesis by autochthonous microbiota; establishing an optimal concentration of surfactant to prevent exhibition of antimicrobial properties and rapid biodegradation; research both in laboratory and field conditions.

  14. Electrokinetic investigation of surfactant adsorption.

    Science.gov (United States)

    Bellmann, C; Synytska, A; Caspari, A; Drechsler, A; Grundke, K

    2007-05-15

    Fuerstenau [D.W. Fuerstenau, in: M.L. Hair (Ed.), Dekker, New York, 1971, p. 143] has already discussed the role of hydrocarbon chain of surfactants, the effect of alkyl chain length, chain structure and the pH of the solution on the adsorption process of surfactants. Later Kosmulski [M. Kosmulski, Chemical Properties of Material Surfaces, Surfactant Science Series, vol. 102, Dekker, New York, Basel, 2001] included the effect of surfactant concentration, equilibration time, temperature and electrolyte in his approaches. Certainly, the character of the head groups of the surfactant and the properties of the adsorbent surface are the basis for the adsorption process. Different surfactants and adsorbents cause different adsorption mechanisms described firstly by Rosen [M.J. Rosen, Surfactants and Interfacial Phenomena, second ed., Wiley, New York, 1989]. These adsorption mechanisms and their influencing factors were studied by electrokinetic investigations. Here only changes of the charges at the surfaces could be detected. To control the results of electrokinetic investigations they were compared with results from ellipsometric measurements. In the case of surfactant adsorption the chain length was vitally important. It could be shown by the adsorption of alkyl trimethyl ammonium bromides onto polymer films spin coated at wafer surfaces. The influence of the chain length depending on surface properties of the polymer film was studied. Streaming potential measurements were applied for these investigations. The obtained results enabled us to calculate the molar cohesive free energy per mol of CH2-group in the alkaline chain of the surfactant if all other specific adsorption effects were neglected.

  15. Effect of Diffusion on Lithium Intercalation in Titanium Dioxide

    Science.gov (United States)

    Koudriachova, Marina V.; Harrison, Nicholas M.; de Leeuw, Simon W.

    2001-02-01

    A new model of Li intercalation into rutile and anatase structured titania has been developed from first principles calculations. The model includes both thermodynamic and kinetic effects and explains the observed differences in intercalation behavior and their temperature dependence. The important role of strong local deformations of the lattice and elastic screening of interlithium interactions is demonstrated. In addition, a new phase of LiTiO2 is reported.

  16. The effect of an intercalated BSc on subsequent academic performance

    Directory of Open Access Journals (Sweden)

    Sewell Hannah

    2011-10-01

    Full Text Available Abstract Background The choice of whether to undertake an intercalated Bachelor of Science (BSc degree is one of the most important decisions that students must make during their time at medical school. An effect on exam performance would improve a student's academic ranking, giving them a competitive edge when applying for foundation posts. Methods Retrospective data analysis of anonymised student records. The effects of intercalating on final year exam results, Foundation Programme score, application form score (from white-space questions, quartile rank score, and success with securing Foundation School of choice were assessed using linear and ordered logistic regression models, adjusted for course type, year of graduation, graduate status and baseline (Year 1 performance. Results The study included 1158 students, with 54% choosing to do an intercalated BSc, and 9.8% opting to do so at an external institution. Doing an intercalated BSc was significantly associated with improved outcome in Year 5 exams (P = 0.004. This was irrespective of the year students chose to intercalate, with no significant difference between those that intercalated after years 2, 3 and 4 (p = 0.3096. There were also higher foundation application scores (P Conclusions Doing an intercalated BSc leads to an improvement in subsequent exam results and develops the skills necessary to produce a strong foundation programme application. It also leads to greater success with securing preferred Foundation School posts in students. Differences between internally- and externally-intercalating students may be due to varying course structures or greater challenge in adjusting to a new study environment.

  17. Anaerobic Biodegradation of Detergent Surfactants

    Directory of Open Access Journals (Sweden)

    Erich Jelen

    2009-03-01

    Full Text Available Detergent surfactantscan be found in wastewater in relevant concentrations. Most of them are known as ready degradable under aerobic conditions, as required by European legislation. Far fewer surfactants have been tested so far for biodegradability under anaerobic conditions. The natural environment is predominantly aerobic, but there are some environmental compartments such as river sediments, sub-surface soil layer and anaerobic sludge digesters of wastewater treatment plants which have strictly anaerobic conditions. This review gives an overview on anaerobic biodegradation processes, the methods for testing anaerobic biodegradability, and the anaerobic biodegradability of different detergent surfactant types (anionic, nonionic, cationic, amphoteric surfactants.

  18. Synthesis and Characterization of Highly Intercalated Graphite Bisulfate

    Science.gov (United States)

    Salvatore, Marcella; Carotenuto, Gianfranco; De Nicola, Sergio; Camerlingo, Carlo; Ambrogi, Veronica; Carfagna, Cosimo

    2017-03-01

    Different chemical formulations for the synthesis of highly intercalated graphite bisulfate have been tested. In particular, nitric acid, potassium nitrate, potassium dichromate, potassium permanganate, sodium periodate, sodium chlorate, and hydrogen peroxide have been used in this synthesis scheme as the auxiliary reagent (oxidizing agent). In order to evaluate the presence of delamination, and pre-expansion phenomena, and the achieved intercalation degree in the prepared samples, the obtained graphite intercalation compounds have been characterized by scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS), X-ray powder diffraction (XRD), infrared spectroscopy (FT-IR), micro-Raman spectroscopy ( μ-RS), and thermal analysis (TGA). Delamination and pre-expansion phenomena were observed only for nitric acid, sodium chlorate, and hydrogen peroxide, while the presence of strong oxidizers (KMnO4, K2Cr2O7) led to stable graphite intercalation compounds. The largest content of intercalated bisulfate is achieved in the intercalated compounds obtained from NaIO4 and NaClO3.

  19. Genotoxicity of non-covalent interactions: DNA intercalators

    Energy Technology Data Exchange (ETDEWEB)

    Ferguson, Lynnette R. [Auckland Cancer Society Research Centre, Faculty of Medical and Health Science, University of Auckland (New Zealand)], E-mail: l.ferguson@auckland.ac.nz; Denny, William A. [Auckland Cancer Society Research Centre, Faculty of Medical and Health Science, University of Auckland (New Zealand)

    2007-10-01

    This review provides an update on the mutagenicity of intercalating chemicals, as carried out over the last 17 years. The most extensively studied DNA intercalating agents are acridine and its derivatives, that bind reversibly but non-covalently to DNA. These are frameshift mutagens, especially in bacteria and bacteriophage, but do not otherwise show a wide range of mutagenic properties. Di-acridines or di-quinolines may be either mono- or bis-intercalators, depending upon the length of the alkyl chain separating the chromophores. Those which monointercalate appear as either weak frameshift mutagens in bacteria, or as non-mutagens. However, some of the bisintercalators act as 'petite' mutagens in Saccharomyces cerevisiae, suggesting that they may be more likely to target mitochondrial as compared with nuclear DNA. Some of the new methodologies for detecting intercalation suggest this may be a property of a wider range of chemicals than previously recognised. For example, quite a number of flavonoids appear to intercalate into DNA. However, their mutagenic properties may be dominated by the fact that many of them are also able to inhibit topoisomerase II enzymes, and this property implies that they will be potent recombinogens and clastogens. DNA intercalation may serve to position other, chemically reactive molecules, in specific ways on the DNA, leading to a distinctive (and wider) range of mutagenic properties, and possible carcinogenic potential.

  20. Fixation of enzyme protein in soil by the clay mineral montmorillonite

    DEFF Research Database (Denmark)

    Sørensen, L.H.

    1969-01-01

    Aminosäureverbindungen, die im Boden während des biologischen Abbaus von Kohlehydraten gebildet und vom Tonmineral Montmorillonit stabilisiert werden, haben Enzymcharakter und sind folglich Proteine....

  1. Solid state oxidation of phenols to quinones with sodium perborate on wet montmorillonite K10

    Energy Technology Data Exchange (ETDEWEB)

    Hashemi, Mohammed M.; Eftekhari-Sis, Bagher; Khalili, Behzad; Karimi-Jaberi, Zahed [Sharif University of Technology, Tehran (Iran, Islamic Republic of). Dept. of Chemistry]. E-mail: mhashemi@sharif.edu

    2005-09-15

    Phenols were oxidized to quinones using sodium perborate (SPB) on wet montmorillonite as oxidant. The reaction was carried out at ambient temperature on the solid phase under solvent free conditions. (author)

  2. Electro-rheological properties of montmorillonite particles coated with titania in methyl silicone oil

    Institute of Scientific and Technical Information of China (English)

    ZHANG Xu-ping; XU Ling-li; WANG Qing-liang

    2008-01-01

    Montmorillonite particles coated with titania were synthesized by means of a sol-gel method to use with elec-tro-theological material. The characteristics of these composite particles were studied by X-ray diffraction, scanning electron mi-croscopy (SEM) and Fourier transform infrared spectroscopy (FT-IR). The electro-rheological (ER) effects were measured after these particles were mixed with methyl-silicon oil by 20% and 30% (weight percent). The experimental results show that these montmorillonite/titania particles exhibit a marked ER effect compared with pure montmorillonite particles under a DC electric field.The highest static yield stress is up to 4.28 kPa, which is an increase of about 3.13 kPa over that of untreated montmorillonite pow-der under the electrical field strength of 3.2 kV/mm at room temperature.

  3. Exfoliated polypyrrole-organically modified montmorillonite clay nanocomposite as a potential adsorbent for Cr (VI) removal

    CSIR Research Space (South Africa)

    Setshedi, KZ

    2013-01-01

    Full Text Available Exfoliated polypyrrole-organically modified montmorillonite clay nanocomposite (PPy OMMT NC), was prepared as a potential adsorbent, via in situ polymerization of pyrrole monomer for adsorption of toxic Cr(VI) from aqueous solution. The WAXD...

  4. Efficient iodination of aromatic compounds using potassium ferrate supported on montmorillonite

    Institute of Scientific and Technical Information of China (English)

    Hoda Keipour; Mohammad A. Khalilzadeh; Bita Mohtat; Abolfazl Hosseini; Daryoush Zareyee

    2011-01-01

    Potassium ferrate impregnated on montmorillonite is a mild, cheap, and non-toxic reagent for the iodination of phenols, including naphthol, aromatic amines, and heterocyclic substrates in fair to excellent yields by a simple isolation procedure.

  5. Plasmon-assisted degradation of methylene blue with Ag/AgCl/montmorillonite nanocomposite under visible light

    Science.gov (United States)

    Sohrabnezhad, Sh.; Zanjanchi, M. A.; Razavi, M.

    2014-09-01

    Metal-semiconductor compounds, such as Ag/AgX (X = Cl, Br, I), enable visible light absorption and separation of photogenerated electron-hole through surface plasmon resonance (SPR) effect. However, the electron-hole generated and separated by light are vulnerable in Ag/AgX phase because of the occurrence of secondary recombined. In order to more effectively utilize the SPR photocatalytic effect, nanoparticles are located in a matrix. In this article, Ag/AgCl nanoparticles were synthesized in montmorillonite (MMT) matrix using dispersion method and light irradiation. The structure, composition and optical properties of such material were investigated by transmission electron microscopy (TEM), UV-visible diffuse reflectance spectroscopy (UV-Vis DRS), X-ray diffraction (XRD) and FTIR. Powder X-ray diffraction showed intercalation of Ag/AgCl nanoparticles into the clay layers. The as-prepared plasmonic photocatalyst exhibited an enhanced and stable photoactivity for the degradation of methylene blue (MB) under visible light. The high activity was attributed to the surface plasmon resonance (SPR) exhibited by Ag nanoparticles on the surface of AgCl. The detection of reactive species by radical scavengers displays that rad O2- and rad OH- are the main reactive species for the degradation of MB under visible light irradiation. The studies showed that 20 min illumination under visible light can complete degradation of methylene blue (MB), and indicate a high stability of photocatalytic degradation. The mechanism of separation of the photo-generated electrons and holes at the Ag/AgCl-MMT nanocomposite was discussed.

  6. A novel ion-exchange carrier based upon liposome-encapsulated montmorillonite for ophthalmic delivery of betaxolol hydrochloride

    Science.gov (United States)

    Huang, Yi; Tao, Qi; Hou, Dongzhi; Hu, Sheng; Tian, Shuangyan; Chen, Yanzhong; Gui, Ruyi; Yang, Lingling; Wang, Yao

    2017-01-01

    As a novel ion-exchange carrier with high surface area and excellent exchangeability, montmorillonite (Mt) was intercalated with betaxolol hydrochloride (BH) to form a nanocomposite and then encapsulated by liposomes (Mt-BH-LPs) for an ophthalmic drug-delivery system. The Mt-BH and Mt-BH-LPs were prepared by an acidification process and ethanol injection combined with ammonium sulfate gradient methods. The successful formation of Mt-BH and Mt-BH-LPs was verified by thermogravimetric analysis, X-ray diffraction, Fourier-transform infrared spectra, and transmission electron microscopy. Mt-BH-LPs possessed the favorable physical characteristics of encapsulation efficiency, drug loading, mean particle size, and ζ-potential. In vitro release studies indicated Mt-BH-LPs effectively maintained a relatively sustained slow release. Immortalized human corneal epithelial cell cytotoxicity, in vivo rabbit eye-irritation tests, and chorioallantoic membrane–trypan blue staining all revealed that Mt-BH-LPs had no obvious irritation on ocular tissues. A new in vitro tear-turnover model, including inserts containing human corneal epithelial cells, was designed to evaluate the precorneal retention time of Mt-BH-LPs. The results showed that Mt-BH-LPs maintained a certain BH concentration in tear fluid for a longer period than the BH solution. In vivo precorneal retention studies also indicated Mt-BH-LPs prolonged drug retention on the ocular surface more than the BH solution. Furthermore, pharmacodynamic studies showed that Mt-BH-LPs had a prolonged effect on decreasing intraocular optical pressure in rabbits. Our results demonstrated that Mt-BH-LPs have potential as an ophthalmic delivery system. PMID:28280338

  7. Plasmon-assisted degradation of methylene blue with Ag/AgCl/montmorillonite nanocomposite under visible light.

    Science.gov (United States)

    Sohrabnezhad, Sh; Zanjanchi, M A; Razavi, M

    2014-09-15

    Metal-semiconductor compounds, such as Ag/AgX (X=Cl, Br, I), enable visible light absorption and separation of photogenerated electron-hole through surface plasmon resonance (SPR) effect. However, the electron-hole generated and separated by light are vulnerable in Ag/AgX phase because of the occurrence of secondary recombined. In order to more effectively utilize the SPR photocatalytic effect, nanoparticles are located in a matrix. In this article, Ag/AgCl nanoparticles were synthesized in montmorillonite (MMT) matrix using dispersion method and light irradiation. The structure, composition and optical properties of such material were investigated by transmission electron microscopy (TEM), UV-visible diffuse reflectance spectroscopy (UV-Vis DRS), X-ray diffraction (XRD) and FTIR. Powder X-ray diffraction showed intercalation of Ag/AgCl nanoparticles into the clay layers. The as-prepared plasmonic photocatalyst exhibited an enhanced and stable photoactivity for the degradation of methylene blue (MB) under visible light. The high activity was attributed to the surface plasmon resonance (SPR) exhibited by Ag nanoparticles on the surface of AgCl. The detection of reactive species by radical scavengers displays that O2- and OH- are the main reactive species for the degradation of MB under visible light irradiation. The studies showed that 20 min illumination under visible light can complete degradation of methylene blue (MB), and indicate a high stability of photocatalytic degradation. The mechanism of separation of the photo-generated electrons and holes at the Ag/AgCl-MMT nanocomposite was discussed.

  8. Effect of Montmorillonite Clay upon the polycondensation of Lactic Acid

    Science.gov (United States)

    El Amine, Belaouedj Mohammed; Mohammed, Belbachir

    2008-08-01

    The development of synthetic biodegradable polymers, such as poly(α-hydroxy acid), is particularly important for constructing medical devices, drug delivery systems, including scaffolds and sutures, and has attracted growing interest in the biomedical field. Here, we report a novel approach to preparing poly(D, L-lactic acid) (PDLA) as a biodegradable polymer. We investigated in detail the reaction conditions for the simple direct polycondensation of lactic acid, including the reaction times, temperatures, and catalyst. The molecular weight of synthesized PLA is dependent on both the reaction temperature and time. The optimum reaction condition to obtain PDLA by direct polycondensation using Maghnite-H+, a proton exchanged Montmorillonite clay, as catalyst was thus determined to be 120 °C for 28h with a molecular weight of 7970. The method for PDLA synthesis established here will facilitate production of PDLA of various molecular weights, which may have a potential utility as biomaterials.

  9. An Acid Exchanged Montmorillonite Clay-Catalyzed Synthesis of Polyepichlorhydrin

    OpenAIRE

    Ahmed Yahiaoui; Mohammed Belbachir; Aïcha Hachemaoui

    2003-01-01

    “Maghniteâ€Â, a montmorillonite sheet silicate clay, exchanged with protons to produce “H-Maghnite†is an efficient catalyst for cationic polymerisation of many heterocyclic and vinylic monomers (Belbachir, M. U.S. Patent. 066969.0101 –2001). The structural compositions of both “Maghnite†and “H-Maghnite†have already been determined. Epichlorhydrin monomer, which is polymerizable by a cationic process (Odian,G. La Polymerisation: Principes et Applicatio...

  10. Samarium Ion Exchanged Montmorillonite for High Temperature Cumene Cracking Reaction

    Science.gov (United States)

    Binitha, N. N.; Silija, P. P.; Suraj, V.; Yaakob, Z.; Sugunan, S.

    2011-02-01

    Montmorillonite clay is cation exchanged with samarium and its catalytic influence in cumene cracking reaction is investigated. Effect of exchange with sodium ions on further exchange with samarium ions is also noted. Acidity measurements are done using Temperature Programmed Desorption (TPD) of ammonia. The retention of basic structure is proved from FTIR spectra and XRD patterns. Elemental analysis result shows that samarium exchange has occurred, which is responsible for the higher catalytic activity. Surface area and pore volume remains more or less unaffected upon exchange. Thermogravimetric analysis indicates the enhanced thermal stability on exchanging. Cumene cracking reaction is carried out at atmospheric pressure in a fixed bed glass reactor at 673 K. The predominance of Brønsted acidity is confirmed from high selectivity to benzene.

  11. Samarium Ion Exchanged Montmorillonite for High Temperature Cumene Cracking Reaction

    Energy Technology Data Exchange (ETDEWEB)

    Binitha, N N; Silija, P P; Yaakob, Z [Department of Chemical and Process Engineering, Faculty of Engineering and Built Environment, National University of Malaysia, 43600 UKM Bangi, Selangor (Malaysia); School of Materials Engineering, Universiti Malaysia Perlis, Taman Muhibah, 02600, Jejawi, Perlis (Malaysia); Suraj, V [Department of Applied Chemistry, CUSAT, Cochin 22, Kerala (India); Sugunan, S, E-mail: binithann@yahoo.co.in [National Institute of Technology, Calicut, Kerala (India)

    2011-02-15

    Montmorillonite clay is cation exchanged with samarium and its catalytic influence in cumene cracking reaction is investigated. Effect of exchange with sodium ions on further exchange with samarium ions is also noted. Acidity measurements are done using Temperature Programmed Desorption (TPD) of ammonia. The retention of basic structure is proved from FTIR spectra and XRD patterns. Elemental analysis result shows that samarium exchange has occurred, which is responsible for the higher catalytic activity. Surface area and pore volume remains more or less unaffected upon exchange. Thermogravimetric analysis indicates the enhanced thermal stability on exchanging. Cumene cracking reaction is carried out at atmospheric pressure in a fixed bed glass reactor at 673 K. The predominance of Broensted acidity is confirmed from high selectivity to benzene.

  12. Neptunium(V) sorption behavior on clinoptilolite, quartz and montmorillonite

    Energy Technology Data Exchange (ETDEWEB)

    Bertetti, F.P.; Pabalan, R.T.; Turner, D.R.; Almendarez, M.G. [Southwest Research Inst., San Antonio, TX (United States). Center for Nuclear Waste Regulatory Analyses

    1996-08-01

    Performance assessment models have identified {sup 237}Np as a radionuclide of concern in meeting release limits established for the geologic disposal of high-level nuclear waste at the proposed repository at Yucca Mountain, Nevada. In this study, quartz, clinoptilolite, and montmorillonite, which are minerals representative of phases that occur both in the rock matrix and as fracture coatings at Yucca Mountain, were reacted with {sup 237}Np-bearing solutions to characterize the sorption behavior of Np(V) on these minerals. Batch experiments were conducted over a wide range of conditions in which pH of solution, surface loading, sorbent surface area, initial concentration of Np(V), and partial pressure of CO{sub 2} were varied. Initial Np(V) concentrations were between 1 {times} 10{sup {minus}7} and 1 {times} 10{sup {minus}6} M in electrolyte solutions of 0.1 or 0.01 M NaNO{sub 3}. The oxidation state of Np in solution was verified with NIR spectroscopy and by solvent extraction. Prior to the start of experiments, minerals were pretreated to eliminate impurities, and the clinoptilolite and montmorillonite were converted to Na-form by ion exchange with NaCl solutions. Results indicate that, for all three minerals, Np(V) sorption begins at pH values coincident with the start of hydrolysis in solution ({approximately}7). For solutions undersaturated with respect to atmospheric CO{sub 2}, sorption increases continuously with increasing pH. Under equilibrium with atmospheric CO{sub 2}, Np(V) sorption is important in the pH range (7--9.5) where NpO{sub 2}(OH){sup 0}(aq) is significant, whereas sorption is inhibited at higher pH where neptunyl carbonate complexes are the predominant species.

  13. Heterogeneous freezing of water droplets containing kaolinite and montmorillonite particles

    Directory of Open Access Journals (Sweden)

    B. J. Murray

    2010-04-01

    Full Text Available Clouds composed of both ice particles and supercooled liquid water droplets exist at temperatures above ~236 K. These mixed phase clouds, which strongly impact climate, are very sensitive to the presence of solid particles that can catalyse freezing. In this paper we describe experiments to determine the rate at which kaolinite and montmorillonite nucleate ice when immersed within water droplets. These are the first immersion mode experiments in which the ice nucleating ability of individual minerals has been determined quantitatively. Water droplets containing a known amount of clay mineral were supported on a hydrophobic surface and cooled at a rate of 10 K min−1. The temperatures at which individual 10–40 μm diameter droplets froze were determined by optical microscopy. As the concentration of kaolinite in the droplets was increased from 0.005 wt% to 1 wt% the median nucleation temperature increased from close to the homogeneous nucleation limit (236 K to 240.8±0.6 K. We go onto show that the probability of freezing scales with surface area of the kaolinite inclusions rather than, as is often assumed, the volume of the droplet. When droplets contained montmorillonite ice always nucleated at 245.8±0.6 K, independent of the mineral concentration. We report temperature dependent nucleation rates and present parameterisations for nucleation by these minerals which capture the surface area and cooling rate dependence of the nucleation rate. We show that our parameterisations produce significantly different results to parameterisations employed in global models. These results also highlight the importance of understanding the ice nucleating properties of individual minerals rather than complex mixtures of minerals found in natural dusts and so-called test dusts.

  14. Interstratified Illite/Montmorillonite in Kamojang Geothermal Field, Indonesia

    Directory of Open Access Journals (Sweden)

    D. F. Yudiantoro

    2014-07-01

    Full Text Available DOI: 10.17014/ijog.v8i4.167Kamojang geothermal field located in West Java Province, falls under the Pangkalan Subregency, Bandung Regency. The researched area is a geothermal field located in the Quaternary volcanic caldera system of about 0.452 to 1.2 Ma. The volcanic activity generated hydrothermal fluids, interacting with rocks producing mineral alteration. The minerals formed in the areas of research are interstratified illite/montmorillonite (I/M. Analyses to identify interstratified I/M have been performed by X-ray diffraction using ethylene glycol, while the determination of the type and percentage of interstratified I/M was based on the calculation method of Watanabe. The methodology was applied on core and cutting samples from Wells KMJ-8, 9, 11, 13, 16, 23, 49, 51, and 54. The result of analysis of the samples shows that the type of clay is interstratified illite/montmorillonite and the minerals are formed at temperatures ranging from 180 to 220° C. The type of interstratified I/M in the studied area is S = 0 and S = 1. The percentage of illite type S = 0 is between 20 - 35% illite, whereas type S = 1 has about 45 - 72% illite. Along with the increasing depth, the percentage of illite is getting greater. This is consistent with the vertical distribution of temperature which increases according to the depth. This correlation results in an interpretation that the upflow zone of the geothermal reservoir is located in the centre of the Kamojang geothermal field.

  15. Interstratified Illite/Montmorillonite in Kamojang Geothermal Field, Indonesia

    Directory of Open Access Journals (Sweden)

    D. F. Yudiantoro

    2014-07-01

    Full Text Available DOI: 10.17014/ijog.v8i4.167Kamojang geothermal field located in West Java Province, falls under the Pangkalan Subregency, Bandung Regency. The researched area is a geothermal field located in the Quaternary volcanic caldera system of about 0.452 to 1.2 Ma. The volcanic activity generated hydrothermal fluids, interacting with rocks producing mineral alteration. The minerals formed in the areas of research are interstratified illite/montmorillonite (I/M. Analyses to identify interstratified I/M have been performed by X-ray diffraction using ethylene glycol, while the determination of the type and percentage of interstratified I/M was based on the calculation method of Watanabe. The methodology was applied on core and cutting samples from Wells KMJ-8, 9, 11, 13, 16, 23, 49, 51, and 54. The result of analysis of the samples shows that the type of clay is interstratified illite/montmorillonite and the minerals are formed at temperatures ranging from 180 to 220° C. The type of interstratified I/M in the studied area is S = 0 and S = 1. The percentage of illite type S = 0 is between 20 - 35% illite, whereas type S = 1 has about 45 - 72% illite. Along with the increasing depth, the percentage of illite is getting greater. This is consistent with the vertical distribution of temperature which increases according to the depth. This correlation results in an interpretation that the upflow zone of the geothermal reservoir is located in the centre of the Kamojang geothermal field.

  16. Synthesis of silver nanoparticles in montmorillonite and their antibacterial behavior

    Directory of Open Access Journals (Sweden)

    Shameli K

    2011-03-01

    Full Text Available Kamyar Shameli1, Mansor Bin Ahmad1, Mohsen Zargar2, Wan Md Zin Wan Yunus1, Abdolhossein Rustaiyan3, Nor Azowa Ibrahim11Department of Chemistry, Faculty of Science, Universiti Putra Malaysia, Serdang, Selangor, Malaysia; 2Department of Biology, Faculty of Science, Islamic Azad University, Qom Branch, Qom, Iran; 3Department of Chemistry, Science and Research Branch, Islamic Azad University, Tehran, IranAbstract: Silver nanoparticles (Ag NPs were synthesized by the chemical reducing method in the external and interlamellar space of montmorillonite (MMT as a solid support at room temperature. AgNO3 and NaBH4 were used as a silver precursor and reducing agent, respectively. The most favorable experimental conditions for synthesizing Ag NPs in the MMT are described in terms of the initial concentration of AgNO3. The interlamellar space limits changed little (d-spacing = 1.24–1.47 nm; therefore, Ag NPs formed on the MMT suspension with d-average = 4.19–8.53 nm diameter. The Ag/MMT nanocomposites (NCs, formed from AgNO3/MMT suspension, were characterizations with different instruments, for example UV-visible, PXRD, TEM, SEM, EDXRF, FT-IR, and ICP-OES analyzer. The antibacterial activity of different sizes of Ag NPs in MMT were investigated against Gram-positive, ie, Staphylococcus aureus and methicillin-resistant S. aureus (MRSA and Gram-negative bacteria, ie, Escherichia coli, Escherichia coli O157:H7, and Klebsiella pneumoniae, by the disk diffusion method using Mueller-Hinton agar (MHA. The smaller Ag NPs were found to have significantly higher antibacterial activity. These results showed that Ag NPs can be used as effective growth inhibitors in different biological systems, making them applicable to medical applications.Keywords: silver nanoparticles, nanoparticles, montmorillonite, antibacterial activity, Mueller-Hinton agar 

  17. Heterogeneous allylsilylation of aromatic and aliphatic alkenes catalyzed by proton-exchanged montmorillonite.

    Science.gov (United States)

    Motokura, Ken; Matsunaga, Shigekazu; Miyaji, Akimitsu; Sakamoto, Yasuharu; Baba, Toshihide

    2010-04-02

    Allylsilylation of an alkene is the only known procedure to install both silyl and allyl groups onto a carbon-carbon double bond directly. Proton-exchanged montmorillonite showed excellent catalytic performances for the allylsilylation of alkenes. For example, the reaction of p-chlorostyrene with allyltrimethylsilane proceeded smoothly to afford the corresponding allylsilylated product in 95% yield. We also attempted to isolate the reaction intermediate on the montmorillonite surface to investigate the reaction mechanism.

  18. Solvent Free Preparation of p-Cymene from Limonene Using Vietnamese Montmorillonite

    DEFF Research Database (Denmark)

    Nguyen, Thao-Tran Thi; Duus, Fritz; Le, Thach Ngoc

    2013-01-01

    p-Cymene, an important intermediate in industrial chemistry, has been prepared in good yields by thermally induced dehydrogenation of limonene under solvent-free reaction conditions using Vietnamese montmorillonite as an efficient green catalyst.......p-Cymene, an important intermediate in industrial chemistry, has been prepared in good yields by thermally induced dehydrogenation of limonene under solvent-free reaction conditions using Vietnamese montmorillonite as an efficient green catalyst....

  19. Influence of the organic complex concentration on adsorption of herbicide in organic modified montmorillonite

    Science.gov (United States)

    Kaludjerovic, Lazar; Tomic, Zorica; Djurovic, Rada; Milosevic, Maja

    2016-04-01

    Pesticides are recognized as an important source of potential pollution to soil and water due to their mobility and degradation in soils. Results presented in this paper show impact of the organic complex concentration on the adsorption of herbicides (acetochlor) at the surface of the organic modified montmorillonite. In this work, natural montmorillonite from Bogovina, located near Boljevac municipality, was used for organic modification. Cation-exchange capacity of this montmorillonite was determined by extraction with ammonium acetate (86 mmol/100g of clay). Montmorillonite have been modified first with NaCl and than with two organic complexes, hexadecyltrimethylammonium bromide (HDTMA) and phenyltrimethylammonium chloride (PTMA). For both organic complexes, three saturation concentrations were selected for monitoring of the herbicide adsorption (43 mmol/100g of clay (0.5 CEC), 86 mmol/100g of clay (1 CEC) and 129 mmol/100g of clay (1.5 CEC)). Changes in the properties of the inorganic and organic bentonite have been examined using the X-ray powder diffraction (XRPD) and batch equilibrium method. Increase in basal spacing (d) of montmorillonites saturated with 1.5 CEC of organic cation indicate that sorption of PTMA and HDTMA can exceed the saturation of 1 CEC. Both organic montmorillonites have shown higher uptake of the herbicide, compared to the inorganic montmorillonite. Comparing the values Freundlich coefficients in batch equilibrium method, (presented in the form of log Kf and 1/n), it can be seen that the sorption decreases in the series: 0.5CEC> 1CEC> 1.5CEC> NaM, for both organic montmorillonites.

  20. Treatment with exogenous surfactant stimulates endogenous surfactant synthesis in premature infants with respiratory distress syndrome

    NARCIS (Netherlands)

    Bunt, JEH; Carnielli, VP; Janssen, DJ; Wattimena, JLD; Hop, WC; Sauer, PJ; Zimmermann, LJI

    2000-01-01

    Objective: Treatment of preterm infants with respiratory distress syndrome (RDS) with exogenous surfactant has greatly improved clinical outcome. Some infants require multiple doses, and it has not been studied whether these large amounts of exogenous surfactant disturb endogenous surfactant metabol

  1. Adsorption of Carbon Dioxide, Methane, and Their Mixtute by Montmorillonite in the Presence of Water

    KAUST Repository

    Kadoura, Ahmad Salim

    2016-01-16

    Using grand canonical Monte Carlo (GCMC) simulations, we study the adsorption behavior of CH4, CO2, and their mixture at 298.15 K and pressures up to 50 bar in Na-, Cs-, and Ca-montmorillonite clays in the presence of water. Montmorillonite clays in the presence of preadsorbed water, preferentially adsorb CO2 over CH4 during both pure component and mixture adsorption. The atomistic model we have used, gives good agreement with available single-component experimental adsorption isotherms, for CH4 and CO2 molecules adsorbed onto montmorillonite clays in the presence of water. We observe the general trend that the presence of increasing preadsorbed water content in the clay interlayers, reduced adsorption amounts of pure CH4 and CO2 molecules. With a relatively large basal spacing (d= 30 Å), the favorability of adsorption of CO2 by montmorillonite at relatively low pressures and intermediate water contents has been demonstrated using simulations. GCMC simulation is also used to assess the effect of water on the adsorption of N2/CH4, H2 S/CH4, CO2/N2, and CO2/H2 S binary mixtures in Na-montmorillonite clay. The ideal adsorbed solution theory is shown to agree well with the observed adsorption capacities and selectivities of mixtures in Na-montmorillonite clay.

  2. A Density Functional Theory Study of a Calcium- Montmorillonite: A First Investigation for Medicine Application

    Science.gov (United States)

    Dewi Kencana Wungu, Triati; Fauzan, Muhammad Rifqi Al; Widayani; Suprijadi

    2016-08-01

    In this study, we performed structural geometry and electronic properties calculations of calcium - based clay mineral for medicine application using first principles calculation by means of Density Functional Theory. Here, a kind of clay mineral used was Ca- montmorillonite and it is applied as an absorber of dangerous metal contained in a human body, such as Pb, which causes osteoporosis. Osteoporosis is a disease associated with bone mass decreases. Since montmorillonite has ability to exchange its cation (Ca+2), therefore, it plays an important role in preventing or/and cure human bone from osteoporosis. In order to understand how Ca-montmorillonite can do detoxification in the human body, we firstly investigated the mechanism of Pb adsorption on the surface of Ca-montmorillonite in an atomic level point of view. We found that the repulsive interactions between H of OH groups with Ca and Pb yielding the rotation of the H of OH groups of montmorillonite. A relatively small movement of Ca was observed when Pb is adsorbed and the band gap of Ca- montmorillonite becomes 1.87 eV narrow.

  3. Electron microscopic observation of montmorillonite swelled by water with the aid of hydrophilic ionic liquid

    Energy Technology Data Exchange (ETDEWEB)

    Takahashi, Chisato [Advanced Ceramics Research Center, Nagoya Institute of Technology, Honmachi 3-101-1, Tajimi, Gifu 507-0033 (Japan); Department of Pharmaceutical Engineering, School of Pharmacy, Aichi Gakuin University, Kusumoto 1-100, Chikusa, Nagoya, Aichi 464-8650 (Japan); Shirai, Takashi [Advanced Ceramics Research Center, Nagoya Institute of Technology, Honmachi 3-101-1, Tajimi, Gifu 507-0033 (Japan); Fuji, Masayoshi, E-mail: fuji@nitech.ac.jp [Advanced Ceramics Research Center, Nagoya Institute of Technology, Honmachi 3-101-1, Tajimi, Gifu 507-0033 (Japan)

    2013-09-16

    The morphology and structure of hydrous montmorillonite in different swelling condition have been observed with the aid of hydrophilic ionic liquid (IL; 1-Butyl-3-methylimidazolium Tetrafluoroborate) using electron microscope. The observation mechanism of hydrous montmorillonite with layer structure using IL was revealed by swelling behavior as measured by X-ray diffraction (XRD) and transmission electron microscopy (TEM) with selected area electron diffraction pattern (SAED). The morphology of hydrous montmorillonite containing a large amount of water was also successfully observed by field emission electron microscope (FE-SEM). In addition, the inductively coupled plasma (ICP) and thermogravimetric – differential thermal analysis (TG-DTA) results showed the ion-exchange behavior of hydrous montmorillonite during the IL treatment. The technique allowed the exact morphology to be observed of hydrated materials with layer structure in civil engineering, cosmetics, medical and agricultural fields. - Highlights: • Observation of two different conditions of hydrated montmorillonite was investigated. • The swelling structure by water molecules was characterized by TEM. • The observation mechanism of hydrous montmorillonite was revealed. • Ionic liquid is useful for characterization of hydrated materials with layer structure.

  4. Discriminating Intercalative Effects of Threading Intercalator Nogalamycin, from Classical Intercalator Daunomycin, Using Single Molecule Atomic Force Spectroscopy.

    Science.gov (United States)

    Banerjee, T; Banerjee, S; Sett, S; Ghosh, S; Rakshit, T; Mukhopadhyay, R

    2016-01-01

    DNA threading intercalators are a unique class of intercalating agents, albeit little biophysical information is available on their intercalative actions. Herein, the intercalative effects of nogalamycin, which is a naturally-occurring DNA threading intercalator, have been investigated by high-resolution atomic force microscopy (AFM) and spectroscopy (AFS). The results have been compared with those of the well-known chemotherapeutic drug daunomycin, which is a non-threading classical intercalator bearing structural similarity to nogalamycin. A comparative AFM assessment revealed a greater increase in DNA contour length over the entire incubation period of 48 h for nogalamycin treatment, whereas the contour length increase manifested faster in case of daunomycin. The elastic response of single DNA molecules to an externally applied force was investigated by the single molecule AFS approach. Characteristic mechanical fingerprints in the overstretching behaviour clearly distinguished the nogalamycin/daunomycin-treated dsDNA from untreated dsDNA-the former appearing less elastic than the latter, and the nogalamycin-treated DNA distinguished from the daunomycin-treated DNA-the classically intercalated dsDNA appearing the least elastic. A single molecule AFS-based discrimination of threading intercalation from the classical type is being reported for the first time.

  5. Discriminating Intercalative Effects of Threading Intercalator Nogalamycin, from Classical Intercalator Daunomycin, Using Single Molecule Atomic Force Spectroscopy.

    Directory of Open Access Journals (Sweden)

    T Banerjee

    Full Text Available DNA threading intercalators are a unique class of intercalating agents, albeit little biophysical information is available on their intercalative actions. Herein, the intercalative effects of nogalamycin, which is a naturally-occurring DNA threading intercalator, have been investigated by high-resolution atomic force microscopy (AFM and spectroscopy (AFS. The results have been compared with those of the well-known chemotherapeutic drug daunomycin, which is a non-threading classical intercalator bearing structural similarity to nogalamycin. A comparative AFM assessment revealed a greater increase in DNA contour length over the entire incubation period of 48 h for nogalamycin treatment, whereas the contour length increase manifested faster in case of daunomycin. The elastic response of single DNA molecules to an externally applied force was investigated by the single molecule AFS approach. Characteristic mechanical fingerprints in the overstretching behaviour clearly distinguished the nogalamycin/daunomycin-treated dsDNA from untreated dsDNA-the former appearing less elastic than the latter, and the nogalamycin-treated DNA distinguished from the daunomycin-treated DNA-the classically intercalated dsDNA appearing the least elastic. A single molecule AFS-based discrimination of threading intercalation from the classical type is being reported for the first time.

  6. Electrochemical Oscillations Induced by Surfactants

    Institute of Scientific and Technical Information of China (English)

    翟俊红; 贺占博

    2003-01-01

    A new type of electrochemical oscillation induced by surfactant was observed in experiments. The electrochemical system is a Daniell cell with a copper rod in CuSO4 aqueous and an aluminum rod in Al(NO3)3 aqueous as electrodes. The surfactants are CTAB, TX-100, SLS. The addition of trace surfactant solution by a micro-syringe made the original monotonously changing electrochemical system produce obvious periodic phenomena. At the mean time, the copper ion selective electrode and Hg2SO4 reference electrode were used to monitor the copper electrode reaction and determine its rate constant k of first order reaction. According to the experimental results of electrode reaction kinetics, the possible mechanism was found to be the polarization induced from the directional adsorption of trace surfactant on the electrode surface. That is the electrochemical oscillations.

  7. Persurf, a New Method to Improve Surfactant Delivery: A Study in Surfactant Depleted Rats

    OpenAIRE

    2012-01-01

    PURPOSE: Exogenous surfactant is not very effective in adults with ARDS, since surfactant does not reach atelectatic alveoli. Perfluorocarbons (PFC) can recruit atelectatic areas but do not replace impaired endogenous surfactant. A surfactant-PFC-mixture could combine benefits of both therapies. The aim of the proof-of-principal-study was to produce a PFC-in-surfactant emulsion (Persurf) and to test in surfactant depleted Wistar rats whether Persurf achieves I.) a more homogenous pulmonary di...

  8. SYNTHESIS OF Fe2O3-MONTMORILLONITE AND ITS APPLICATION AS A PHOTOCATALYST FOR DEGRADATION OF CONGO RED DYE

    Directory of Open Access Journals (Sweden)

    Karna Wijaya

    2010-06-01

    Full Text Available The preparation of Fe2O3-montmorillonite and it's application as a catalyst for congo red dye photodegradation has been carried out. Fe2O3-montmorillonite was prepared by mixing the iron complexes pillaring agent and montmorillonite. The product was calcined at 250 oC for 5 hours. Montmorillonite and calcined product was analyzed by X-ray diffractometry (X-RD, infrared spectrophotometry (FTIR, gas  sorption analyser, X-ray fluorescense (X-RF and UV/Vis diffuse reflectance spektrophotometry (UV-DRS. Fe2O3-montmorilonite then was used as a catalyst on congo red dye photodegrdation by UV-illuminating a mixture of 50 mg Fe2O3-montmorillonite and 25 mL congo red 10­-4M at 365 nm at various illuminating times. Adsorption of congo red on Fe2O3-montmorillonite and montmorillonite was also performed as a comparison. Result of X-RD analysis showed that the 001 reflection of  Fe2O3-montmorillonite was not  detected that probably indicating the formation of house of card stucture and this result was supported also by the analysis result of distribution of pores and SEM photography result. Results of the XRF analysis showed that iron content increased  from 5.21 % (w/w in montmorillonite to 25.12 % (w/w in Fe2O3-montmorillonite. UV- DRS analysis showed the increament of band gap energy from 3.69 eV in the iron oxide bulk to 3.8 eV in Fe2O3-montmorillonite. Specific surface area of the montmorillonite also increased significantly from 69,71 m2/g to 126,49 m2/g and total pores volume increased from 50.70x10-3 mL/Å/g  to 107.89x10-3 mL/Å/g, respectively. Photodegradation of congo red using Fe2O3-montmorillonite caused the decreament of congo red concentration up to 90.22 %  on UV illumination for 60 minutes. Adsorption of congo red on Fe2O3-montmorillonite reached 84.4% and on  montmorillonite was 75.15 %.   Keywords: photodegradation, congo red, Fe2O3-montmorillonite, UV light

  9. Dodecylsulfate and dodecybenzenesulfonate intercalated hydrotalcites as adsorbent materials for the removal of BBR acid dye from aqueous solutions

    Directory of Open Access Journals (Sweden)

    Mohamed Bouraada

    2016-07-01

    Full Text Available Two modified layered double hydroxides (HT have been synthesized by intercalating both sodium dodecylsulfate (SDS and sodium dodecylbenzenesulfonate (SDBS surfactants into Mg-Al layered double hydroxides using the calcination–rehydratation method. The prepared materials HT-SDS and HT-SDBS were characterized by X-ray diffraction, FTIR, thermal analysis and BET. The obtained materials were used for Brilliant Blue R (BBR dye removal from aqueous solution. Batch studies were carried out to address various experimental parameters such as kinetic, pH, sorption isotherm and temperature. Sorption experiments of acid dye BBR from aqueous solution by HT-SDS and HT-SDBS were investigated in the batch system. Kinetic studies indicate that the sorption of BBR follows the pseudo-second-order model. Sorption capacities of HT-SDS (357.1 mg/g for BBR dye were much higher than those of HT-SDBS (204.1 mg/g. The intercalated Mg-Al layered double hydroxides with SDS and SDBS could possibly be used to remove anionic dyes of relatively high concentrations, whereas HT-CO3 may only be used to remove anionic dyes of low concentrations.

  10. Sequence-specific intercalating agents: intercalation at specific sequences on duplex DNA via major groove recognition by oligonucleotide-intercalator conjugates.

    Science.gov (United States)

    Sun, J S; François, J C; Montenay-Garestier, T; Saison-Behmoaras, T; Roig, V; Thuong, N T; Hélène, C

    1989-01-01

    An acridine derivative was covalently linked to the 5' end of a homopyrimidine oligonucleotide. Specific binding to a homopurine-homopyrimidine sequence of duplex DNA was demonstrated by spectroscopic studies (absorption and fluorescence) and by "footprinting" experiments with a copper phenanthroline chelate used as an artificial nuclease. A hypochromism and a red shift of the acridine absorption were observed. Triple-helix formation was also accompanied by a hypochromism in the ultraviolet range. The fluorescence of the acridine ring was quenched by a stacking interaction with a G.C base pair adjacent to the homopurine-homopyrimidine target sequence. The intercalating agent strongly stabilized the complex formed by the oligopyrimidine with its target duplex sequence. Cytosine methylation further increased the stability of the complexes. Footprinting studies revealed that the oligopyrimidine binds in a parallel orientation with respect to the homopurine-containing strand of the duplex. The intercalated acridine extended by 2 base pairs the region of the duplex protected by the oligopyrimidine against degradation by the nuclease activity of the copper phenanthroline chelate. Random intercalation of the acridine ring was lost due to the repulsive effect of the negatively charged oligonucleotide tail. Intercalation occurred only at those double-stranded sequences where the homopyrimidine oligonucleotide recognized the major groove of duplex DNA. Images PMID:2594761

  11. Biomimicry of surfactant protein C.

    Science.gov (United States)

    Brown, Nathan J; Johansson, Jan; Barron, Annelise E

    2008-10-01

    Since the widespread use of exogenous lung surfactant to treat neonatal respiratory distress syndrome, premature infant survival and respiratory morbidity have dramatically improved. Despite the effectiveness of the animal-derived surfactant preparations, there still remain some concerns and difficulties associated with their use. This has prompted investigation into the creation of synthetic surfactant preparations. However, to date, no clinically used synthetic formulation is as effective as the natural material. This is largely because the previous synthetic formulations lacked analogues of the hydrophobic proteins of the lung surfactant system, SP-B and SP-C, which are critical functional constituents. As a result, recent investigation has turned toward the development of a new generation of synthetic, biomimetic surfactants that contain synthetic phospholipids along with a mimic of the hydrophobic protein portion of lung surfactant. In this Account, we detail our efforts in creating accurate mimics of SP-C for use in a synthetic surfactant replacement therapy. Despite SP-C's seemingly simple structure, the predominantly helical protein is extraordinarily challenging to work with given its extreme hydrophobicity and structural instability, which greatly complicates the creation of an effective SP-C analogue. Drawing inspiration from Nature, two promising biomimetic approaches have led to the creation of rationally designed biopolymers that recapitulate many of SP-C's molecular features. The first approach utilizes detailed SP-C structure-activity relationships and amino acid folding propensities to create a peptide-based analogue, SP-C33. In SP-C33, the problematic and metastable polyvaline helix is replaced with a structurally stable polyleucine helix and includes a well-placed positive charge to prevent aggregation. SP-C33 is structurally stable and eliminates the association propensity of the native protein. The second approach follows the same design

  12. Investigating the Intercalation Chemistry of Alkali Ions in Fluoride Perovskites

    Energy Technology Data Exchange (ETDEWEB)

    Yi, Tanghong; Chen, Wei; Cheng, Lei; Bayliss, Ryan D.; Lin, Feng; Plews, Michael R.; Nordlund, Dennis; Doeff, Marca M.; Persson, Kristin A.; Cabana, Jordi

    2017-02-07

    Reversible intercalation reactions provide the basis for modern battery electrodes. Despite decades of exploration of electrode materials, the potential for materials in the nonoxide chemical space with regards to intercalation chemistry is vast and rather untested. Transition metal fluorides stand out as an obvious target. To this end, we report herein a new family of iron fluoride-based perovskite cathode materials AxK1–xFeF3 (A = Li, Na). By starting with KFeF3, approximately 75% of K+ ions were subsequently replaced by Li+ and Na+ through electrochemical means. X-ray diffraction and Fe X-ray absorption spectroscopy confirmed the existence of intercalation of alkali metal ions in the perovskite structure, which is associated with the Fe2+/3+ redox couple. A computational study by density functional theory showed agreement with the structural and electrochemical data obtained experimentally, which suggested the possibility of fluoride-based materials as potential intercalation electrodes. This study increases our understanding of the intercalation chemistry of ternary fluorides, which could inform efforts toward the exploration of new electrode materials.

  13. Durability of Intercalated Graphite Epoxy Composites in Low Earth Orbit

    Science.gov (United States)

    Gaier, James R.; Davidson, Michelle L.; Shively, Rhonda

    1996-01-01

    The electrical conductivity of graphite epoxy composites can be substantially increased by intercalating (inserting guest atoms or molecules between the graphene planes) the graphite fibers before composite formation. The resulting high strength, low density, electrically conducting composites have been proposed for EMI shielding in spacecraft. Questions have been raised, however, about their durability in the space environment, especially with respect to outgassing of the intercalates, which are corrosive species such as bromine. To answer those concerns, six samples of bromine intercalated graphite epoxy composites were included in the third Evaluation of Oxygen Interaction with Materials (EOIM-3) experiment flown on the Space Shuttle Discovery (STS-46). Changes in electrical conductivity, optical reflectance, surface texture, and mass loss for SiO2 protected and unprotected samples were measured after being exposed to the LEO environment for 42 hours. SiO2 protected samples showed no degradation, verifying conventional protection strategies are applicable to bromine intercalated composites. The unprotected samples showed that bromine intercalation does not alter the degradation of graphite-epoxy composites. No bromine was detected to have been released by the fibers allaying fears that outgassing could be disruptive to the sensitive electronics the EMI shield is meant to protect.

  14. Surfactant for pediatric acute lung injury.

    Science.gov (United States)

    Willson, Douglas F; Chess, Patricia R; Notter, Robert H

    2008-06-01

    This article reviews exogenous surfactant therapy and its use in mitigating acute lung injury (ALI) and the acute respiratory distress syndrome (ARDS) in infants, children, and adults. Biophysical and animal research documenting surfactant dysfunction in ALI/ARDS is described, and the scientific rationale for treatment with exogenous surfactant is discussed. Major emphasis is placed on reviewing clinical studies of surfactant therapy in pediatric and adult patients who have ALI/ARDS. Particular advantages from surfactant therapy in direct pulmonary forms of these syndromes are described. Also discussed are additional factors affecting the efficacy of exogenous surfactants in ALI/ARDS.

  15. Rheology of polyaniline-dinonylnaphthalene disulfonic acid (DNNDSA) montmorillonite clay nanocomposites in the sol state: shear thinning versus pseudo-solid behavior.

    Science.gov (United States)

    Garai, Ashesh; Nandi, Arun K

    2008-04-01

    The melt rheology of polyaniline (PANI)-dinonylnaphthalenedisulfonic acid (DNNDSA) gel nanocomposites (GNCs) with organically modified (modified with cetyl trimethylammonium bromide)-montmorillonite (om-MMT) clay has been studied for three different clay concentrations at the temperature range 120-160 degrees C. Field emission scanning electron microscopy (FE-SEM), wide angle X-ray scattering (WAXS), differential scanning calorimetry (DSC) and dc-conductivity data (approximately 10(-3) S/cm) indicate that the PANI-DNNDSA melt is in sol state and it is not de-doped at that condition. The WAXS data indicate that in GNC-1 sol clay tactoids are in exfoliated state but in the other sols they are in intercalated state. The zero shear viscosity (eta0), storage modulus (G') and loss modulus (G") increase than that of pure gel in the GNCs. The pure sol and the sols of gel nanocomposites (GNCs) exhibit Newtonian behavior for low shear rate (solid at higher frequency where G' and loss modulus (G") show a crossover point in the frequency sweep experiment at a fixed temperature. The crossover frequency decreases with increase in clay concentration and it increases with increase in temperature for GNC sols. The pseudo-solid behavior has been explained from jamming or network formation of clay tactoids under shear. A probable explanation of the two apparently contradictory phenomena of shear thinning versus pseudo-solid behavior of the nanocomposite sols is discussed.

  16. Characterization of polyurethane/organophilic montmorillonite nanocomposites by low field NMR; Caracterizacao de nanocompositos de poliuretano/montmorilonita organofilica por RMN de baixo campo

    Energy Technology Data Exchange (ETDEWEB)

    Silva, Marcos Anacleto da [Universidade Federal do Rio de Janeiro (UFRJ), RJ (Brazil). Laboratorio de Nanocompositos Polimericos; Tavares, Maria I.B.; Nascimento, Suelen A.M.; Rodrigues, Elton J. da R [Universidade Federal do Rio de Janeiro (NUCAT/PEQ/COPPE/UFRJ), RJ (Brazil). Laboratorio de Nanocompositos Polimericos

    2012-07-01

    Polyurethanes are important and versatile materials, mainly due to some of their properties, such as high resistance to abrasion and tearing, excellent absorption of mechanical shocks and good flexibility and elasticity. However, they have some drawbacks as well, such as low thermal stability and barrier properties. To overcome these disadvantages, various studies have been conducted involving organophilic polyurethane/montmorillonite nanocomposites. The investigation of the structure of polyurethane/clay nanocomposites has mainly been done by X-ray diffraction (XRD) and transmission electron microscopy (TEM). In this work, PU/clay nanocomposite films obtained by solution intercalation were studied. The nanocomposites were characterized by XRD and low-field nuclear magnetic resonance (LF-NMR). The LF-NMR measurements, with determination of the spin-lattice relaxation time of the hydrogen nucleus, supplied important information about the molecular dynamics of these nanocomposites. The X-ray diffraction measurements validated the results found by NMR. The thermal stability of the material was also determined by thermogravimetric analysis (TGA) under an inert atmosphere. A slight improvement in this stability was observed in the nanocomposite in comparison with polyurethane (author)

  17. Improved breakdown strength and electrical energy storage performance of γ-poly(vinylidene fluoride)/unmodified montmorillonite clay nano-dielectrics

    Science.gov (United States)

    Ghosh, Sujoy Kumar; Rahman, Wahida; Ranjan Middya, Tapas; Sen, Shrabanee; Mandal, Dipankar

    2016-05-01

    A remarkable improvement in the dielectric breakdown strength (E b) and discharge energy density (U e) of flexible polymer nanocomposites is realized by the incorporation of unmodified smectite montmorillonite (MMT) nanoclay into a poly(vinylidene fluoride) (PVDF) matrix. The resulting PVDF/MMT clay nanocomposite (PCN) films stabilize the γ phase and increase the path tortuosity via strong intercalation of the PVDF matrix into inorganic layered silicates without sacrificing the quality of surface morphology. The PCN films exhibits superior dielectric properties (up to ɛ r ˜ 28 and tan δ ˜ 0.032 at 1 kHz) than those of pure PVDF. As a result, a large increase in E b of 873 MV m-1 and U e of 24.9 J cm-3 is achieved. Subsequently, the PCN films possess more than 60% charge-discharge efficiency even at higher electric field and thus provide a scope to develop high energy density flexible and transparent materials for energy storage technologies.

  18. Synthesis and characterization of thermally stable poly(amide-imide-montmorillonite nanocomposites based on bis(4-carboxyphenyl-N,N'-pyromellitimide acid

    Directory of Open Access Journals (Sweden)

    M. Hajibeygi

    2013-04-01

    Full Text Available Two new poly(amide-imide-montmorillonite reinforced nanocomposites containing bis(4-carboxyphenyl-N,N'-pyromellitimide acid moiety in the main chain were synthesized by a convenient solution intercalation technique. Poly(amide-imide (PAI as a source of polymer matrix was synthesized by the direct polycondensation reaction of bis(4-carboxyphenyl-N,N'-pyromellitimide acid with 4,4'-diamino diphenyl sulfone in the presence of triphenyl phosphite (TPP, CaCl2, pyridine and N-methyl-2-pyrrolidone (NMP. Morphology and structure of the resulting PAI-nanocomposite films with 10 and 20% silicate particles were characterized by FT-IR spectroscopy, X-ray diffraction (XRD and scanning electron microscopy (SEM. The effect of clay dispersion and the interaction between clay and polymeric chains on the properties of nanocomposites films were investigated by using UV-Vis spectroscopy, thermal gravimetry analysis (TGA and water uptake measurements.DOI: http://dx.doi.org/10.4314/bcse.v27i1.10

  19. The effect of exchangeable cations in clinoptilolite and montmorillonite on the adsorption of aflatoxin B1

    Directory of Open Access Journals (Sweden)

    DRAGAN STOJSIC

    2001-08-01

    Full Text Available The adsorption of aflatoxin B1 (AFB1 by cation-exchanged clinoptilolite zeolitic tuff and montmorillonite was investigated at 37°C and pH 3.8 from an aqueous electrolyte having a composition similar to that of gastric juices of animals. Both minerals were exchanged from the natural form to the sodium form and then to the Cu2+, Zn2+ and Co2+-rich forms. The cation exchange was different for the different cations, but in all cases the exchanges were larger on montmorillonite than on clinoptilolite. The degree of exchange on montmorillonite was 76 % for copper (from a total of CEC 0.95 meq/g, Cu2+ –0.73 meq/g and 85 % for zinc and cobalt. Under the same conditions (concentration, temperature, pH, contact time, the degree of exchange on zeolitic tuff was 12 % for Cu2+ (from a total CEC of 1.46 meq/g, Cu2+ –0.17 meq/g, 8 % for Zn2+ and 10 % for Co2+. Both groups of mineral adsorbents showed high AFB1 chemisorption indexes (ca. For the montmorillonite forms, ca ranged from 0.75 for the Cu-exchanged montmorillonite to 0.89 for the natural Ca-form, 0.90 for the Zn-exchanged form and 0.93 for the Co-exchanged montmorillonite. The adsorption of AFB1 on the different exchanged forms of clinoptilolite gave similar values of ca for the Cu and Ca forms (0.90 and values of 0.94 and 0.95 for the Zn- and Co-exchanged form. The impact of the mineral adsorbents on the reduction of essential nutrients present in animal feed (Cu, Zn, Mn and Co showed that the Ca-rich montmorillonite had a higher capability for the reduction of the microelements than the Ca-rich clinoptilolite.

  20. Tunable thermal expansion in framework materials through redox intercalation.

    Science.gov (United States)

    Chen, Jun; Gao, Qilong; Sanson, Andrea; Jiang, Xingxing; Huang, Qingzhen; Carnera, Alberto; Rodriguez, Clara Guglieri; Olivi, Luca; Wang, Lei; Hu, Lei; Lin, Kun; Ren, Yang; Lin, Zheshuai; Wang, Cong; Gu, Lin; Deng, Jinxia; Attfield, J Paul; Xing, Xianran

    2017-02-09

    Thermal expansion properties of solids are of fundamental interest and control of thermal expansion is important for practical applications but can be difficult to achieve. Many framework-type materials show negative thermal expansion when internal cages are empty but positive thermal expansion when additional atoms or molecules fill internal voids present. Here we show that redox intercalation offers an effective method to control thermal expansion from positive to zero to negative by insertion of Li ions into the simple negative thermal expansion framework material ScF3, doped with 10% Fe to enable reduction. The small concentration of intercalated Li ions has a strong influence through steric hindrance of transverse fluoride ion vibrations, which directly controls the thermal expansion. Redox intercalation of guest ions is thus likely to be a general and effective method for controlling thermal expansion in the many known framework materials with phonon-driven negative thermal expansion.

  1. The preliminary feasibility of intercalated graphite railgun armatures

    Science.gov (United States)

    Gaier, James R.; Gooden, Clarence E.; Yashan, Doreen; Naud, Steve

    1991-01-01

    Graphite intercalation compounds may provide an excellent material for the fabrication of electromagnetic railgun armatures. As a pulse of power is fed into the armature the intercalate could be excited into the plasma state around the edges of the armature, while the bulk of the current would be carried through the graphite block. Such an armature would have both diffuse plasma armatures and bulk conduction armatures. In addition, the highly anisotropic nature of these materials could enable the electrical and thermal conductivity to be tailored to meet the specific requirements of electromagnetic railgun armatures. Preliminary investigations have been performed in an attempt to determine the feasibility of using graphite intercalation compounds as railgun armatures. Issues of fabrication, resistivity, stability, and electrical current spreading have been addressed for the case of highly oriented pyrolytic graphite.

  2. Progressive specification rather than intercalation of segments during limb regeneration.

    Science.gov (United States)

    Roensch, Kathleen; Tazaki, Akira; Chara, Osvaldo; Tanaka, Elly M

    2013-12-13

    An amputated salamander limb regenerates the correct number of segments. Models explaining limb regeneration were largely distinct from those for limb development, despite the presence of common patterning molecules. Intercalation has been an important concept to explain salamander limb regeneration, but clear evidence supporting or refuting this model was lacking. In the intercalation model, the first blastema cells acquire fingertip identity, creating a gap in positional identity that triggers regeneration of the intervening region from the stump. We used HOXA protein analysis and transplantation assays to show that axolotl limb blastema cells acquire positional identity in a proximal-to-distal sequence. Therefore, intercalation is not the primary mechanism for segment formation during limb regeneration in this animal. Patterning in development and regeneration uses similar mechanisms.

  3. Electrochemical synthesis of alkali-intercalated iron selenide superconductors

    Science.gov (United States)

    Shen, Shi-Jie; Ying, Tian-Ping; Wang, Gang; Jin, Shi-Feng; Zhang, Han; Lin, Zhi-Ping; Chen, Xiao-Long

    2015-11-01

    Electrochemical method has been used to insert K/Na into FeSe lattice to prepare alkali-intercalated iron selenides at room temperature. Magnetization measurement reveals that KxFe2Se2 and NaxFe2Se2 are superconductive at 31 K and 46 K, respectively. This is the first successful report of obtaining metal-intercalated FeSe-based high-temperature superconductors using electrochemical method. It provides an effective route to synthesize metal-intercalated layered compounds for new superconductor exploration. Project supported by the National Natural Science Foundation of China (Grant Nos. 51322211and 91422303), the Strategic Priority Research Program (B) of the Chinese Academy of Sciences (Grant No. XDB07020100), Beijing Nova Program of China (Grant No. 2011096), and K. C. Wong Education Foundation, Hong Kong, China.

  4. The preliminary feasibility of intercalated graphite railgun armatures

    Science.gov (United States)

    Gaier, James R.; Gooden, Clarence E.; Yashan, Doreen; Naud, Steve

    1991-01-01

    Graphite intercalation compounds may provide an excellent material for the fabrication of electromagnetic railgun armatures. As a pulse of power is fed into the armature the intercalate could be excited into the plasma state around the edges of the armature, while the bulk of the current would be carried through the graphite block. Such an armature would have both diffuse plasma armatures and bulk conduction armatures. In addition, the highly anisotropic nature of these materials could enable the electrical and thermal conductivity to be tailored to meet the specific requirements of electromagnetic railgun armatures. Preliminary investigations have been performed in an attempt to determine the feasibility of using graphite intercalation compounds as railgun armatures. Issues of fabrication, resistivity, stability, and electrical current spreading have been addressed for the case of highly oriented pyrolytic graphite.

  5. Properties of sodium-intercalated indium and gallium selenides

    Energy Technology Data Exchange (ETDEWEB)

    Kovalyuk, Z.D.; Luk' yanyuk, V.K.

    1988-03-01

    The authors present the results of an investigation of some physicochemical properties of Na/sub x/InSe and Na/sub x/GaSe (chemical potential, diffusion of the intercalant) and they give an interpretation of the results based on the thermodynamic model of intercalants, constructed for dye chalcogenides of transition metals. Electrochemical and theoretical investigations indicate that first-stage structures form in the concentration ranges x = 0.15-1 for Na/sub x/GaSe. Calculations based on the use of the lattice-gas theory agree well with the experimental data and make it possible to determine the energy of interaction of intercalated ions in the van der Waals gap.

  6. Drug-DNA intercalation: from discovery to the molecular mechanism.

    Science.gov (United States)

    Mukherjee, Arnab; Sasikala, Wilbee D

    2013-01-01

    The ability of small molecules to perturb the natural structure and dynamics of nucleic acids is intriguing and has potential applications in cancer therapeutics. Intercalation is a special binding mode where the planar aromatic moiety of a small molecule is inserted between a pair of base pairs, causing structural changes in the DNA and leading to its functional arrest. Enormous progress has been made to understand the nature of the intercalation process since its idealistic conception five decades ago. However, the biological functions were detected even earlier. In this review, we focus mainly on the acridine and anthracycline types of drugs and provide a brief overview of the development in the field through various experimental methods that led to our present understanding of the subject. Subsequently, we discuss the molecular mechanism of the intercalation process, free-energy landscapes, and kinetics that was revealed recently through detailed and rigorous computational studies.

  7. Real-time electrochemical LAMP: a rational comparative study of different DNA intercalating and non-intercalating redox probes.

    Science.gov (United States)

    Martin, Alexandra; Bouffier, Laurent; Grant, Kathryn B; Limoges, Benoît; Marchal, Damien

    2016-06-20

    We present a comparative study of ten redox-active probes for use in real-time electrochemical loop-mediated isothermal amplification (LAMP). Our main objectives were to establish the criteria that need to be fulfilled for minimizing some of the current limitations of the technique and to provide future guidelines in the search for ideal redox reporters. To ensure a reliable comparative study, each redox probe was tested under similar conditions using the same LAMP reaction and the same entirely automatized custom-made real-time electrochemical device (designed for electrochemically monitoring in real-time and in parallel up to 48 LAMP samples). Electrochemical melt curve analyses were recorded immediately at the end of each LAMP reaction. Our results show that there are a number of intercalating and non-intercalating redox compounds suitable for real-time electrochemical LAMP and that the best candidates are those able to intercalate strongly into ds-DNA but not too much to avoid inhibition of the LAMP reaction. The strongest intercalating redox probes were finally shown to provide higher LAMP sensitivity, speed, greater signal amplitude, and cleaner-cut DNA melting curves than the non-intercalating molecules.

  8. Anisotropic Tuning of Graphite Thermal Conductivity by Lithium Intercalation.

    Science.gov (United States)

    Qian, Xin; Gu, Xiaokun; Dresselhaus, Mildred S; Yang, Ronggui

    2016-11-17

    Understanding thermal transport in lithium intercalated layered materials is not only important for managing heat generation and dissipation in lithium ion batteries but also the understanding potentially provides a novel way to design materials with reversibly tunable thermal conductivity. In this work, the thermal conductivity of lithium-graphite intercalation compounds (LixC6) is calculated using molecular dynamics simulations as a function of the amount of lithium intercalated. We found that intercalation of lithium has an anisotropic effect on tuning the thermal conductivity: the thermal conductivity in the basal plane decreases monotonically from 1232 W/m·K of pristine graphite to 444 W/m·K of the fully lithiated LiC6, while the thermal conductivity along the c-axis decreases first from 6.5 W/m·K for graphite to 1.3 W/m·K for LiC18 and then increases to 5.0 W/m·K for LiC6 as the lithium composition increases. More importantly, we provide the very first atomic-scale insight into the effect of lithium intercalation on the spectral phonon properties of graphite. The intercalated lithium ions are found to suppress the phonon lifetime and to reduce the group velocity of phonons parallel to the basal plane but significantly to increase the phonon group velocity along the c-axis, which anisotropically tunes the thermal conductivity of lithiated graphite compounds. This work could shed some light on the search for tunable thermal conductivity materials and might have strong impacts on the thermal management of lithium ion batteries.

  9. Surfactant recovery from water using foam fractionation

    Energy Technology Data Exchange (ETDEWEB)

    Tharapiwattananon, N.; Osuwan, S. [Chulalongkorn Univ., Bangkok (Thailand); Scamehorn, J.F. [Inst. of Oklahoma, Norman, OK (United States)] [and others

    1996-05-01

    The purpose of this study was to investigate the use of foam fractionation to recover surfactant from water. A simple continuous mode foam fractionation was used and three surfactants were studied (two anionic and one cationic). The effects of air flow rate, foam height, liquid height, liquid feed surfactant concentration, and sparger porosity were studied. This technique was shown to be effective in either surfactant recovery or the reduction of surfactant concentration in water to acceptable levels. As an example of the effectiveness of this technique, the cetylpyridinium chloride concentration in water can be reduced by 90% in one stage with a liquid residence time of 375 minutes. The surfactant concentration in the collapsed foam is 21.5 times the feed concentration. This cationic surfactant was easier to remove from water by foam fractionation than the anionic surfactants studied.

  10. Synthesis of carbohydrate-based surfactants

    Energy Technology Data Exchange (ETDEWEB)

    Pemberton, Jeanne E.; Polt, Robin L.; Maier, Raina M.

    2016-11-22

    The present invention provides carbohydrate-based surfactants and methods for producing the same. Methods for producing carbohydrate-based surfactants include using a glycosylation promoter to link a carbohydrate or its derivative to a hydrophobic compound.

  11. Pyrene intercalating nucleic acids with a carbon linker.

    Science.gov (United States)

    Østergaard, Michael E; Wamberg, Michael C; Pedersen, Erik B

    2011-03-01

    We have synthesized a carbon linker analogue of INA (oligonucleotides containing insertions of 1-O-(1-pyrenylmethyl)glycerol). Thermal stability studies showed an increase in melting temperature in favor of the carbon linker analogue. We also synthesized a carbon linker analogue with two pyrenes geminally attached. Fluorescence studies of this intercalating nucleic acid with the pyrene moieties inserted as a bulge showed formation of an excimer band. When a mismatch was introduced at the site of the intercalator, an excimer band was formed for the destabilized duplexes whereas an exciplex band was observed when the stability of the duplex was retained.

  12. Design and synthesis of threading intercalators to target DNA.

    Science.gov (United States)

    Howell, Lesley A; Gulam, Rosul; Mueller, Anja; O'Connell, Maria A; Searcey, Mark

    2010-12-01

    Threading intercalators are high affinity DNA binding agents that bind by inserting a chromophore into the duplex and locating one group in each groove. The first threading intercalators that can be conjugated to acids, sulfonic acids and peptides to target them to duplex DNA are described, based upon the well studied acridine-3- or 4-carboxamides. Cellular uptake of the parent acridine is rapid and it can be visualized in the nucleus of cells. Both the parent compounds and their conjugates maintain antitumor activity.

  13. Phase transitions in the lattice model of intercalation

    Directory of Open Access Journals (Sweden)

    T.S. Mysakovych

    2008-12-01

    Full Text Available The lattice model which can be employed for the description of intercalation of ions in crystals is considered in this work. Pseudospin formalism is used in describing the interaction of electrons with ions. The possibility of hopping of intercalated ions between different positions is taken into account. The thermodynamics of the model is investigated in the mean field approximation. Phase diagrams are built. It is shown that at high values of the parameter of ion transfer, the phase transition to a modulated phase disappears.

  14. New polyelectrolyte complex from pectin/chitosan and montmorillonite clay.

    Science.gov (United States)

    da Costa, Marcia Parente Melo; de Mello Ferreira, Ivana Lourenço; de Macedo Cruz, Mauricio Tavares

    2016-08-01

    A new nanocomposite hydrogel was prepared by forming a crosslinked hybrid polymer network based on chitosan and pectin in the presence of montmorillonite clay. The influence of clay concentration (0.5 and 2% wt) as well as polymer ratios (1:1, 1:2 and 2:1) was investigated carefully. The samples were characterized by different techniques: transmission and scanning electron microscopy, X-ray diffraction, thermogravimetric analysis, infrared spectroscopy, swelling degree and compression test. Most samples presented swelling degree above 1000%, which permits characterizing them as superabsorbent material. Images obtained by transmission electron microscopy showed the presence of clay nanoparticles into hydrogel. The hydrogels' morphological properties were evaluated by scanning electron microscope in high and low-vacuum. The micrographs showed that the samples presented porous. The incorporation of clay produced hydrogels with differentiated morphology. Thermogravimetric analysis results revealed that the incorporation of clay in the samples provided greater thermal stability to the hydrogels. The compression resistance also increased with addition of clay.

  15. Effect of sonication on the particle size of montmorillonite clays.

    Science.gov (United States)

    Poli, Alessandra L; Batista, Tatiana; Schmitt, Carla C; Gessner, Fergus; Neumann, Miguel G

    2008-09-15

    This paper reports on the effect of sonication on SAz-1 and SWy-1 montmorillonite suspensions. Changes in the size of the particles of these materials and modifications of their properties have been investigated. The variation of the particle size has been analyzed by DLS (dynamic light scattering). In all cases the clay particles show a bimodal distribution. Sonication resulted in a decrease of the larger modal diameter, as well as a reduction of its volume percentage. Simultaneously, the proportion of the smallest particles increases. After 60 min of sonication, SAz-1 presented a very broad particle size distribution with a modal diameter of 283 nm. On the other hand, the SWy-1 sonicated for 60 min presents a bimodal distribution of particles at 140 and 454 nm. Changes in the properties of the clay suspensions due to sonication were evaluated spectroscopically from dye-clay interactions, using Methylene Blue. The acidic sites present in the interlamellar region, which are responsible for dye protonation, disappeared after sonication of the clay. The changes in the size of the scattering particles and the lack of acidic sites after sonication suggest that sonication induces delamination of the clay particles.

  16. Catalytic Ethanol Dehydration over Different Acid-activated Montmorillonite Clays.

    Science.gov (United States)

    Krutpijit, Chadaporn; Jongsomjit, Bunjerd

    2016-01-01

    In the present study, the catalytic dehydration of ethanol to obtain ethylene over montmorillonite clays (MMT) with mineral acid activation including H2SO4 (SA-MMT), HCl (HA-MMT) and HNO3 (NA-MMT) was investigated at temperature range of 200 to 400°C. It revealed that HA-MMT exhibited the highest catalytic activity. Ethanol conversion and ethylene selectivity were found to increase with increased reaction temperature. At 400°C, the HA-MMT yielded 82% of ethanol conversion having 78% of ethylene yield. At lower temperature (i.e. 200 to 300°C), diethyl ether (DEE) was a major product. The highest activity obtained from HA-MMT can be attributed to an increase of weak acid sites and acid density by the activation of MMT with HCl. It can be also proven by various characterization techniques that in most case, the main structure of MMT did not alter by acid activation (excepted for NA-MMT). Upon the stability test for 72 h during the reaction, the MMT and HA-MMT showed only slight deactivation due to carbon deposition. Hence, the acid activation of MMT by HCl is promising to enhance the catalytic dehydration of ethanol.

  17. Adsorption of hydrogen sulfide on montmorillonites modified with iron.

    Science.gov (United States)

    Nguyen-Thanh, Danh; Block, Karin; Bandosz, Teresa J

    2005-04-01

    Sodium-rich montmorillonite was modified with iron in order to introduce active centers for hydrogen sulfide adsorption. In the first modification, interlayer sodium cations were exchanged with iron. In another modification, iron oxocations were introduced to the clay surface. The most elaborated modification was based on doping of iron within the interlayer space of aluminum-pillared clay. The modified clay samples were tested as hydrogen sulfide adsorbents. Iron-doped samples showed a significant improvement in the capacity for H2S removal, despite of a noticeable decrease in microporosity compared to the initial pillared clay. The smallest capacity was obtained for the clay modified with iron oxocations. Variations in adsorption capacity are likely due to differences in the chemistry of iron species, degree of their dispersion on the surface, and accessibility of small pores for H2S molecule. The results suggest that on the surface of iron-modified clay hydrogen sulfide reacts with Fe(+3) forming sulfides or it is catalytically oxidized to SO2 on iron (hydro)oxides. Subsequent oxidation may lead to sulfate formation.

  18. Structure and antibacterial activity of Ce~(3+) exchanged montmorillonites

    Institute of Scientific and Technical Information of China (English)

    OUYANG Yousheng; XIE Yushan; TAN Shaozao; SHI Qingshan; CHEN Yiben

    2009-01-01

    Four kinds of Ce~(3+) exchanged montmorillonites(Ce/MMTs) were prepared by an ion-exchange reaction, and characterized with energy dispersive X-ray analysis (EDX), X-ray difference (XRD), X-ray photoelectron spectroscopy (XPS) and scanning electron micros-copy (SEM). The surface properties and antibacterial activity of Ce/MMTs were also investigated. The chemical compositions of Ce/MMTs were determined, and the cerium of Ce/MMTs was confirmed to be present as trivalent cerium state. The d001 basal spacings of Ce/MMTs were enlarged with the enhancement of the cerium contents, and the particles were formed with irregular shape. On increasing the Ce con-tents of Ce/MMTs, the special surface areas were decreased, but the total pore volumes and the average pore sizes were increased. The anti-bacterial activity of Ce/MMTs is increased with increasing the cerium contents, and 1.5g/L of Ce/MMT-3 containing 11.46wt.% of curium could remove all the Staphylococcus aureus and more than 99.9% of the Escherichia coli within 24.0 h of contact. Moreover, Ce/MMTs dis-played bactericidal activity.

  19. Mechanical Performance of Montmorillonite Dispersed Jute Reinforced Composite

    Directory of Open Access Journals (Sweden)

    Hasan Muhammad Hasibul

    2015-01-01

    Full Text Available Surface treated jute accomplished by chemical treatments which enhanced the adhesion between polyester resin and modified surface within the composite. Baking time for 6 hours also reduced the moisture content and diminishes the hydrophilic properties of the corchorus olitorius jute fiber. Montmorillonite shell type nanoclay was dispersed 1%, 3% and 5% within the jute fiber polyester matrix to enhance the mechanical performance. Effect of temperature and high humidity were evaluated for this nanoclay filled composite through hydrothermal test for 15 days in the environmental chamber. Environmental degradation was not remarkable due to the exposure of the temperature 80°C and 95% RH for this time period. Ductile properties like yield strength (YS, % of elongation were calculated for two different stoke rate to understand the strain rate effect. 1% addition of nanoclay within the composite shows the better performance in terms of yield, flexural and impact strength while 5% dispersed of nanoclay does not have any beneficial effect within the composite due to the density and non-homogeneous mixture of the clay. Fracture morphology by SEM/ FESEM revealed voids, broken fibers and nano particles within the matrix.

  20. The effect of dispersion technique of montmorillonite on polyisocyanurate nanocomposites

    Science.gov (United States)

    Cabulis, U.; Fridrihsone, A.; Andersons, J.; Vlcek, T.

    2014-05-01

    The biomass represents an abundant, renewable, competitive and low cost resource that can play an alternative role to petrochemical resources. The central topic of the research activity reported is the use of rape seed oil (RO) as a raw material for the production of rigid polyisocyanurate foams (PIR). The content of the renewable resource-derived polymers achieved in ready foams is up to 20%. By using biopolymers as a matrix, a prospective way is to reinforce them with nanoparticles, organically modified clays, for improvement of mechanical properties while, at the same time, replacing petrochemical raw materials. Organoclay Cloisite® 15A was tested as a filler of PIR foams. Three different techniques - ultrasonification, mixing by three-roll mills, and high-pressure homogenization were used for dispergation of nanoclays in polyols. Composite polyisocyanurate foams and solid polymer samples were produced and tested for stiffness and strength. This paper discusses the studies into the use of RO as a renewable source in rigid PIR foams filled with organomodified montmorillonite clay with loadings from 1 to 5% by weight.

  1. Chemical Modification of Poly(epichlorohydrin) Using Montmorillonite Clay

    Institute of Scientific and Technical Information of China (English)

    BEKKAR Fatima; BELBACHIR Mohamed

    2009-01-01

    Cationic ring opening polymerization of epichlorohydrin (1) and acetic anhydride in the presence of Maghnite-H (Mag-H') as a catalyst afforded, ω-diacetylated poly(epichlorohydrin) (P1) in a moderate yield and molecular weight without formation of side products and degradation. P1 was chemically modified with morpholine (2),piperidine (3) and pyrrolidine (4) into the corresponding new functional poly(epichlorohydrin)s (P2-P4) in a moderate reaction conversion. The conversion of P1 into P2-P4 was confirmed by using FTIR and NMR spec-troscopy and the yield was calculated from the elemental analysis data according to the mole fraction concept. The obtained functional polymers were further characterized by thermal analysis which showed a substantial increase of the glass transition temperature (Tg). Thus, the chemical modification of a,ω-acetylated PECH using Mag-H+ of-fers a simple method for obtaining functional polymers. Mag-H+ is a montmorillonite sheet silicate clay exchanged with proton.

  2. An Acid Exchanged Montmorillonite Clay-Catalyzed Synthesis of Polyepichlorhydrin

    Directory of Open Access Journals (Sweden)

    Ahmed Yahiaoui

    2003-09-01

    Full Text Available “Maghnite”, a montmorillonite sheet silicate clay, exchanged with protons to produce “H-Maghnite” is an efficient catalyst for cationic polymerisation of many heterocyclic and vinylic monomers (Belbachir, M. U.S. Patent. 066969.0101 –2001. The structural compositions of both “Maghnite” and “H-Maghnite” have already been determined. Epichlorhydrin monomer, which is polymerizable by a cationic process (Odian,G. La Polymerisation: Principes et Applications; Ed.Technica: New York, 1994; pp 222-226, was used to elucidate the polymerization cationic character. The polymerization was performed under optimum conditions at 20°C. Experiments revealed that the polymerisation induced by “H-Maghnite” proceeds in bulk. In bulk polymerization, Epichlorhydrin conversion increases with increasing “H-Maghnite” concentration and temperature.

  3. Microstructural Characteristic of Montmorillonite and Its Thermal Treatment Products

    Institute of Scientific and Technical Information of China (English)

    WU Pingxiao; MING Caibing; LI Rong

    2005-01-01

    The montmorillonite was studied by different methods, such as chemical analysis, DAT, TG, XRD, IR, AFM and MAS NMR. The experimental results show that the hydroxyl in octahedra sheets begins dehydrating when the thermal treatment temperature reaches 659℃, but the layer structure remains the same,and the corresponding Al(Ⅵ) is turned into Al(Ⅳ) in octahedra sheets. When the temperature reaches 900℃, the layer structure of montmorillontite is destroyed, and the new mineral phase μ-cordierite is found. When the temperature reaches 1200℃, the μ-cordierite phase loses its stability, and decomposes into cristobalite phase and mullite phase.Meanwhile, the recrystallization phenomenon in thermal treatment products is obvious. There is a small quantity of AlⅥ signal in MAS NMR spectrum, corresponding to Al of mullite. When the temperature reaches 1350℃, the cristobalite and mullite phases reduce slightly, and more Fe-cordierite phase appears, corresponding to Fe-cordierite spectrum in XRD and MAS NMR.

  4. Effect of surfactant alkyl chain length on the dispersion, and thermal and dynamic mechanical properties of LDPE/organo-LDH composites

    Directory of Open Access Journals (Sweden)

    2011-05-01

    Full Text Available Low density polyethylene/layered double hydroxide (LDH composites were prepared via melt compounding using different kinds of organo-LDHs and polyethylene-grafted maleic anhydride as the compatibilizer. The organo-LDHs were successfully prepared by converting a commercial MgAl-carbonate LDH into a MgAl-nitrate LDH, which was later modified by anion exchange with linear and branched sodium alkyl sulfates having different alkyl chain lengths (nc = 6, 12 and 20. It was observed that, depending on the size of the surfactant alkyl chain, different degrees of polymer chain intercalation were achieved, which is a function of the interlayer distance of the organo-LDHs, of the packing level of the alkyl chains, and of the different interaction levels between the surfactant and the polymer chains. In particular, when the number of carbon atoms of the surfactant alkyl chain is larger than 12, the intercalation of polymer chains in the interlayer space and depression of the formation of large aggregates of organo-LDH platelets are favored. A remarkable improvement of the thermal-oxidative degradation was evidenced for all of the composites; whereas only a slight increase of the crystallization temperature and no significant changes of both melting temperature and degree of crystallinity were achieved. By thermodynamic mechanical analysis, it was evidenced that a softening of the matrix is may be due to the plasticizing effect of the surfactant.

  5. The influence of montmorillonite content on the kinetics of curing of epoxy nanocomposites

    Directory of Open Access Journals (Sweden)

    Jovičić Mirjana C.

    2012-01-01

    Full Text Available In this work, the attention was paid at the investigation of montmorillonite dispersion in epoxy/amine systems due to improved final properties of the nanocomposites. The influence of different montmorillonite content on the kinetics of curing of epoxy/Jeffamine D-230 systems was followed by differential scanning calorimetry (DSC. The curing of epoxy nanocomposites was performed using dynamic regime at three different heating rates: 5, 10 and 20°C/min. Three isoconversional methods were applied: two integral (Ozawa-Flynn-Wall and Kissinger-Akahira-Sunose methods and one differential (Friedman method. The presence of montmorillonite (MMT causes the beginning of curing at lower temperatures. The shape of the DSC curves has been changed by the addition of MMT, supporting the hypothesis of a change in the reaction mechanism. For hybrids with 3 and 5 wt.% of MMT, the Eα dependence is very similar to those found for the reference system (epoxy/Jeffamine D-230 for the curing degree less than 60%. The hybrid with 10 wt.% of MMT has lower energy activation in regard to the referent system without montmorillonite. Greater differences are observed in the second part of the reaction, where it is known that the curing process is more controlled by diffusion (α>0.60. The Ea value increases at the end of the reaction (α→1, which was observed for all systems, and is more pronounced in the presence of montmorillonite. [Projekat Ministarstva nauke Republike Srbije, br. III45022

  6. New evidence for microstructural evolution model of acid-activated montmorillonite

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    Ca-montmorillonite samples from Choushan treated at various acid concentrations were studied using chemical analysis, XRD, 29Si and 27Al MAS NMR, to investigate the microstructure of the activated montmorillonites.With the increase of acid concentration and dissolution of cations of montmorillonite, the intensity of d(001) decreased obviously and significant changes of the microstructure of Si and Al occurred. There were two new types of structural units of Si atoms formed: (SiO)3SiOH units and Q4(0AI)units. For Al atoms, in the course of activation, the removal of one of a pair of octahedral aluminium atoms from montmorillonite removed two hydroxyl groups and left the other aluminum of the pair in the four-fold coordination. The 27Al signal at δ 54.0 corresponding to Al? arose from the fourcoordinated Al in the octahedral sheet. This study first confirmed, by 2gsi and 27AI MAS NMR spectra, that the model of microstructural evolution for activated montmorillonite postulated by Thomas et al. (1950) is correct.``

  7. Adsorption of Enrofloxacin on montmorillonite: two-dimensional correlation ATR/FTIR spectroscopy study.

    Science.gov (United States)

    Yan, Wei; Zhang, Jianfeng; Jing, Chuanyong

    2013-01-15

    Adsorption of Enrofloxacin (ENR) on minerals dominates the fate and transport of ENR in the environment. In this study, the sorption process of ENR on montmorillonite and the impact of dissolved organic matters (DOMs) on ENR-montmorillonite interactions were investigated using in situ ATR-FTIR spectroscopy and two-dimensional correlation analysis (2D-COS). Negative peaks were observed in the 3400-2900 cm(-1) region due to the loss of hydrated protons at montmorillonite surfaces. The primary characteristic peaks of adsorbed ENR molecules were resolved in the 1800-1100 cm(-1) range. The results of 2D-COS suggested the sorption process was initiated by the interaction of hydrated protons on montmorillonite surfaces with diverse moieties of ENR molecules depending on pH. The sorption mechanism of ENR was mainly cation exchange at acidic condition, charge neutralization at neutral condition, and proton transfer at alkaline condition. DOM could interact with piperazinyl amine groups of dissolved ENR, which changed the interaction sequence of ENR molecule with montmorillonite surfaces. Electrostatic interaction was the predominant driving force for the interaction between DOM and dissolved ENR. H-donor-acceptor interaction and π-π interaction may also be responsible to this interaction. Insights gained from this study improve our understandings on sorption mechanism of ENR and similar ionic organic pollutants in soil systems.

  8. Effects of Concentration and Conformation of Surfactants on Phase Separation of Surfactant-Water-Oil Systems

    Institute of Scientific and Technical Information of China (English)

    袁银权; 邹宪武; 刘昊阳

    2004-01-01

    The effects of surfactants on the phase separation of surfactant-water-oil systems have been investigated by using discontinuous molecular dynamic simulations. The phase separation speed and equilibrium configuration are dependent on the surfactant concentration and conformation. The equilibrium concentration of surfactants at the interface remains constant. With the increasing surfactant concentration, the equilibrium configuration crosses over from the disperse phase to the bicontinuous one. The crossover concentration is estimated. The conformation of the surfactant has little effect on the equilibrium concentration of surfactants at the interface,while it affects the equilibrium configuration after phase separation.

  9. Complex Formation Between Polyelectrolytes and Ionic Surfactants

    OpenAIRE

    1998-01-01

    The interaction between polyelectrolyte and ionic surfactant is of great importance in different areas of chemistry and biology. In this paper we present a theory of polyelectrolyte ionic-surfactant solutions. The new theory successfully explains the cooperative transition observed experimentally, in which the condensed counterions are replaced by ionic-surfactants. The transition is found to occur at surfactant densities much lower than those for a similar transition in non-ionic polymer-sur...

  10. Effect of interlayer cations of montmorillonite on the biodegradation and adsorption of crude oil polycyclic aromatic compounds.

    Science.gov (United States)

    Ugochukwu, Uzochukwu C; Manning, David A C; Fialips, Claire I

    2014-09-01

    Cation exchange capacity, surface acidity and specific surface area are surface properties of clay minerals that make them act as catalysts or supports in most biogeochemical processes hence making them play important roles in environmental control. However, the role of homoionic clay minerals during the biodegradation of polycyclic aromatic compounds is not well reported. In this study, the effect of interlayer cations of montmorillonites in the removal of some crude oil polycyclic aromatic compounds during biodegradation was investigated in aqueous clay/oil microcosm experiments with a hydrocarbon degrading microorganism community. The homoionic montmorillonites were prepared via cation exchange reactions by treating the unmodified montmorillonite with the relevant metallic chloride. The study indicated that potassium-montmorillonite and zinc-montmorillonite did not enhance the biodegradation of the polycyclic aromatic hydrocarbons whereas calcium-montmorillonite, and ferric-montmorillonite enhanced their biodegradation significantly. Adsorption of polycyclic aromatic hydrocarbons was significant during biodegradation with potassium- and zinc-montmorillonite where there was about 45% removal of the polycyclic aromatic compounds by adsorption in the experimental microcosm containing 5:1 ratio (w/w) of clay to oil.

  11. Binding of cationic surfactants to humic substances

    NARCIS (Netherlands)

    Ishiguro, M.; Tan, W.; Koopal, L.K.

    2007-01-01

    Commercial surfactants are introduced into the environment either through waste products or site-specific contamination. The amphiphilic nature of both surfactants and humic substances (HS) leads to their mutual attraction especially when surfactant and HS are oppositely charged. Binding of the cati

  12. Surfactant analysis in oil-containing fluids

    Energy Technology Data Exchange (ETDEWEB)

    Gronsveld, J.; Faber, M.J. (Koninklijke Shell Exploratie en Produktie Laboratorium, Rijswijk (Netherlands))

    The total surfactant concentration in aqueous phase samples can be analysed with a potentiometric titration. In enhanced oil recovery research, however, the surfactant is produced not only in aqueous phase samples but also in oleic phase samples. The oleic constituents in the oliec phase samples interfere in the surfactant analysis and, therefore, the titration method has been adapted. (orig.).

  13. Surfactant adsorption to soil components and soils

    NARCIS (Netherlands)

    Ishiguro, Munehide; Koopal, Luuk K.

    2016-01-01

    Soils are complex and widely varying mixtures of organic matter and inorganic materials; adsorption of surfactants to soils is therefore related to the soil composition. We first discuss the properties of surfactants, including the critical micelle concentration (CMC) and surfactant adsorption on

  14. Preparation and properties of hydrogen-intercalated indium and gallium monoselenides

    Energy Technology Data Exchange (ETDEWEB)

    Koz' mik, I.D.; Kovalyuk, Z.D.; Grigorchak, I.I.; Bakhmatyuk, B.P.

    1987-10-01

    Indium and gallium monoselenides can be intercalated by hydrogen ions. Thermodynamic parameters have been calculated for the intercalation and the proton diffusion coefficient in the van der Waals' spaces has been determined. The effects of hydrogen intercalation on the resistance perpendicular to the layers in InSe and GaSe have been determined.

  15. 辐射技术制备聚丙烯酸/高岭石吸水凝胶%Preparation of superabsorbent polyacrylic acid/montmorillonite composite by radiation techniques

    Institute of Scientific and Technical Information of China (English)

    GAO Deyu; LIU Yuguang; HOU Jing; LI Hong; HEIMANN B Robert

    2005-01-01

    system to reduced the irradiation dose.Changing the degree of neutralization (DN) of AA will change the WAC. However, concerning the product property, it should be controlled at neutral.AA/montmorillonite polymerizes faster in nitrogen gas than that in the air, because the oxygen in the solution can combine with the radicals formed by the irradiation. Meanwhile, with a high dose rate irradiation, the influence of irradiation atmosphere become smaller.The products characterized with XRD showed that the AA intercalated into the laminar of the montmorillonite.In conclusions, SAPC with high water absorption capacity (1500gram water/gram SAPC) was prepared by proper control of the polymerization conditions of the irradiation dose (1-20 kGy), concentration of the irradiation system (2 %-30 %), additives (0.02 %-0.04 %), degree of neutralization of AA and irradiation atmosphere, etc

  16. Persurf, a new method to improve surfactant delivery: a study in surfactant depleted rats.

    Directory of Open Access Journals (Sweden)

    Wolfram Burkhardt

    Full Text Available PURPOSE: Exogenous surfactant is not very effective in adults with ARDS, since surfactant does not reach atelectatic alveoli. Perfluorocarbons (PFC can recruit atelectatic areas but do not replace impaired endogenous surfactant. A surfactant-PFC-mixture could combine benefits of both therapies. The aim of the proof-of-principal-study was to produce a PFC-in-surfactant emulsion (Persurf and to test in surfactant depleted Wistar rats whether Persurf achieves I. a more homogenous pulmonary distribution and II. a more homogenous recruitment of alveoli when compared with surfactant or PFC alone. METHODS: Three different PFC were mixed with surfactant and phospholipid concentration in the emulsion was measured. After surfactant depletion, animals either received 30 ml/kg of PF5080, 100 mg/kg of stained (green dye Curosurf™ or 30 ml/kg of Persurf. Lungs were fixated after 1 hour of ventilation and alveolar aeration and surfactant distribution was estimated by a stereological approach. RESULTS: Persurf contained 3 mg/ml phospholipids and was stable for more than 48 hours. Persurf-administration improved oxygenation. Histological evaluation revealed a more homogenous surfactant distribution and alveolar inflation when compared with surfactant treated animals. CONCLUSIONS: In surfactant depleted rats administration of PFC-in-surfactant emulsion leads to a more homogenous distribution and aeration of the lung than surfactant alone.

  17. Montmorillonite Clay-Based Polyurethane Nanocomposite As Local Triamcinolone Acetonide Delivery System

    Directory of Open Access Journals (Sweden)

    Flávia Carmo Horta Pinto

    2011-01-01

    Full Text Available Biodegradable polyurethane was synthesized by preparing aqueous polyurethane dispersion having poly(caprolactone and poly(ethylene glycol as soft segments. Montmorillonite particles were delaminated within the waterborne polyurethane to produce a nanocomposite. The triamcinolone acetonide (TA, an important corticoid drug, was dispersed into the nanocomposite followed by a drying step to produce an implantable drug delivery system. Infrared (FTIR results demonstrated that the original chemical structure of the TA was preserved after incorporation into the nanocomposite. Wide angle (WAXS and small angle X-ray scattering (SAXS results suggested that TA and clay do not dramatically change the morphology phase of the polymer although they can interact with each other. The presence of montmorillonite particles in the nanocomposite reduced the rate of TA release as compared to the pure polyurethane and enhanced the mechanical properties of the polymer. The overall results indicate that montmorillonite clay-based polyurethane nanocomposite could be potentially applied as local TA delivery system.

  18. Physico-mechanical properties of silanized-montmorillonite reinforced chitosan-co-poly(maleic anhydride) composites

    Science.gov (United States)

    Saputra, O. A.; Fajrin, A.; Nauqinida, M.; Suryanti, V.; Pramono, E.

    2017-07-01

    To solve the problems of dependence on petroleum as starting material in the manufacturing of plastics in Indonesia, green plastic from biopolymer like chitosan to be one of promising options and alternative to replace the conventional plastics. However, to overcome the mechanical and physical properties of chitosan, the addition of reinforcement agent was introduced. In this study, silanized-montmorillonite (sMMt) has been prepared as a reinforcement agent in the chitosan-co-poly(maleic anhydride) (referred as Cs-MAH) matrix. Silanizing of montmorillonite is one of strategy to improve the interaction between montmorillonite and chitosan, consequently, the mechanical properties, tensile strength of composites contained 6 phr of sMMt improved 56.5% to chitosan. Moreover, the presence both MAH and sMMt on the comosites also reduced swelling degree and swelling area by 20.6% and 26.7%.

  19. Exfoliation of Hexagonal Boron Nitride via Ferric Chloride Intercalation

    Science.gov (United States)

    Hung, Ching-cheh; Hurst, Janet; Santiago, Diana; Rogers, Richard B.

    2014-01-01

    Sodium fluoride (NaF) was used as an activation agent to successfully intercalate ferric chloride (FeCl3) into hexagonal boron nitride (hBN). This reaction caused the hBN mass to increase by approx.100 percent, the lattice parameter c to decrease from 6.6585 to between 6.6565 and 6.6569 ?, the x-ray diffraction (XRD) (002) peak to widen from 0.01deg to 0.05deg of the full width half maximum value, the Fourier transform infrared (FTIR) spectrum's broad band (1277/cm peak) to change shape, and new FTIR bands to emerge at 3700 to 2700 and 1600/cm. This indicates hBN's structural and chemical properties are significantly changed. The intercalated product was hygroscopic and interacted with moisture in the air to cause further structural and chemical changes (from XRD and FTIR). During a 24-h hold at room temperature in air with 100 percent relative humidity, the mass increased another 141 percent. The intercalated product, hydrated or not, can be heated to 750 C in air to cause exfoliation. Exfoliation becomes significant after two intercalation-air heating cycles, when 20-nm nanosheets are commonly found. Structural and chemical changes indicated by XRD and FTIR data were nearly reversed after the product was placed in hydrochloric acid (HCl), resulting in purified, exfoliated, thin hBN products.

  20. Enantiospecific kinking of DNA by a partially intercalating metal complex

    KAUST Repository

    Reymer, Anna

    2012-01-01

    Opposite enantiomers of [Ru(phenanthroline) 3] 2+ affect the persistence length of DNA differently, a long speculated effect of helix kinking. Our molecular dynamics simulations confirm a substantial change of duplex secondary structure produced by wedge-intercalation of one but not the other enantiomer. This effect is exploited by several classes of DNA operative proteins. © The Royal Society of Chemistry 2012.

  1. Intercalation of paracetamol into the hydrotalcite-like host

    Science.gov (United States)

    Kovanda, František; Maryšková, Zuzana; Kovář, Petr

    2011-12-01

    Hydrotalcite-like compounds are often used as host structures for intercalation of various anionic species. The product intercalated with the nonionic, water-soluble pharmaceuticals paracetamol, N-(4-hydroxyphenyl)acetamide, was prepared by rehydration of the Mg-Al mixed oxide obtained by calcination of hydrotalcite-like precursor at 500 °C. The successful intercalation of paracetamol molecules into the interlayer space was confirmed by powder X-ray diffraction and infrared spectroscopy measurements. Molecular simulations showed that the phenolic hydroxyl groups of paracetamol interact with hydroxide sheets of the host via the hydroxyl groups of the positively charged sites of Al-containing octahedra; the interlayer water molecules are located mostly near the hydroxide sheets. The arrangement of paracetamol molecules in the interlayer is rather disordered and interactions between neighboring molecules cause their tilting towards the hydroxide sheets. Dissolution tests in various media showed slower release of paracetamol intercalated in the hydrotalcite-like host in comparison with tablets containing the powdered pharmaceuticals.

  2. Intercalation of papain enzyme into hydrotalcite type layered double hydroxide

    Science.gov (United States)

    Zou, N.; Plank, J.

    2012-09-01

    Intercalation of proteolytic enzyme papain into hydrotalcite type LDH structure was achieved by controlled co-precipitation at pH=9.0 in the presence of papain. Characterization of the MgAl-papain-LDH phase was carried out using X-ray powder diffraction (XRD), elemental analysis, infrared spectroscopy (IR) and thermogravimetry (TG). According to XRD, papain was successfully intercalated. The d-value for the basal spacing of MgAl-papain-LDH was found at ˜5.3 nm. Consequently, original papain (hydrodynamic diameter ˜7.2 nm) attains a compressed conformation during intercalation.Formation of MgAl-papain-LDH was confirmed by elemental analysis and transmission electron microscopy (TEM). Under SEM, MgAl-papain-LDH phases appear as nanothin platelets which are intergrown to flower-like aggregates. Steric size and activity of the enzyme was retained after deintercalation from MgAl-LDH framework, as was evidenced by light scattering and UV/vis measurements. Thus, papain is not denatured during intercalation, and LDH is a suitable host structure which can provide a time-controlled release of the biomolecule.

  3. Photostability enhancement of anionic natural dye by intercalation into hydrotalcite.

    Science.gov (United States)

    Kohno, Yoshiumi; Totsuka, Koichi; Ikoma, Shuji; Yoda, Keiko; Shibata, Masashi; Matsushima, Ryoka; Tomita, Yasumasa; Maeda, Yasuhisa; Kobayashi, Kenkichiro

    2009-09-01

    The aim of this study is the improvement of the photostability of several natural anionic dyes, carmine (CM), carthamus yellow (CY), and annatto dye (ANA), by complexation with hydrotalcite. The composite of the dyes and hydrotalcite is prepared by the coprecipitation method. CM is successfully intercalated in the hydrotalcite layer when the amount of introduced CM is large. The photostability of CM in CM/HT composites is superior to the CM adsorbed on silica surface. The effect of the stability enhancement is larger when the amount of introduced CM exceeds 0.23 g/g-host, or when the layer charge density of the hydrotalcite is larger. CY is also stabilized by complexation with hydrotalcite, whereas ANA is not stabilized by complexation with hydrotalcite. The photostability of an anionic natural dye can be improved by intercalation into the hydrotalcite layer, if the dye has a hydrophilic nature and a rather planar structure. The intercalated dye is stabilized by the protection from the attack of the atmospheric oxygen. In addition, contribution of the electrostatic interaction between the positively charged hydrotalcite layer and the intercalated anionic dye is also proposed.

  4. [Raman and infrared spectrograms of organic borate intercalated hydrotalcite].

    Science.gov (United States)

    Zhang, Jing-Yu; Bai, Zhi-Min; Zhao, Dong

    2013-03-01

    The pattern of X-ray diffraction, the Raman and infrared spectra of organic borate intercalated hydrotalcite were discussed. The well crystallized zinc-aluminum layered double hydroxides (Zn-Al LDHs) intercalated by carbonate ions and borate ions were respectively prepared by co-precipitation method. Patterns of X-ray diffraction showed that the (003) reflection of borate-LDHs was sharp and symmetric and shifted to lower angle than that of carbonate-LDHs. The gallery height of borate-LDHs increased from 0. 28 nm to 0.42 nm after intercalation, indicating that interlayered carbonate ions were substituted by borate anions. The Raman and IR spectra showed that specific bands of carbonate ions in the borate-LDHs disappeared, but with the presence of B3O3(OH)4- X B4O5(OH)4(2-) and B(OH)4- in the interlayer galleries. The hydroxide interlayer anions had a significant influence on the band positions in Raman and infrared spectra of modes related to the hydroxyl group. Our results indicate that single phase and pure borate-pillared LDHs can be obtained using tributyl orthoborate as intercalating agents, and the change in the structure and nature of hydrotalcite can be detected precisely by Raman spectroscopy.

  5. Electret effect in intercalated crystals of the AIIIBVI group

    Directory of Open Access Journals (Sweden)

    I.Grygorchak

    2007-01-01

    Full Text Available Measurements of dielectric properties of Ni-intercalated GaSe and InSe have been performed. The present study is aimed at the investigation of the low-admixture region where the intercalation induced electret effect occurs. The effect exhibits pronounced peak-like concentration dependences and a non-monotonous temperature behaviour with maximum magnitudes at low temperatures. Intercalation leads to over tenfold increase of dielectric permittivity over the whole measured frequency range with up to several orders at low frequencies for GaSe. Temperature dependences of the permittivity demonstrate well-defined peaks with localizations and heights strongly depending on the concentration. A microscopic model of order-disorder type has been proposed that considers redistribution of intercalant atoms between non-polar octahedral and polar tetrahedral positions in the crystal van der Waals gaps. Such a redistribution can occur in the form of phase transition to the polar phase (corresponding to the electret effect which is stabilized by the internal field. For the case of octahedral positions being more preferable, the model predicts a peak-like dependence of the crystal polarization on chemical potential due to passing through the interjacent polar phase in accordance with the measured behaviour of the electret effect. The calculated temperature dependences of dielectric susceptibility qualitatively reproduce experimental results for permittivity as well.

  6. High-rate electrochemical energy storage through Li+ intercalation pseudocapacitance.

    Science.gov (United States)

    Augustyn, Veronica; Come, Jérémy; Lowe, Michael A; Kim, Jong Woung; Taberna, Pierre-Louis; Tolbert, Sarah H; Abruña, Héctor D; Simon, Patrice; Dunn, Bruce

    2013-06-01

    Pseudocapacitance is commonly associated with surface or near-surface reversible redox reactions, as observed with RuO2·xH2O in an acidic electrolyte. However, we recently demonstrated that a pseudocapacitive mechanism occurs when lithium ions are inserted into mesoporous and nanocrystal films of orthorhombic Nb2O5 (T-Nb2O5; refs 1,2). Here, we quantify the kinetics of charge storage in T-Nb2O5: currents that vary inversely with time, charge-storage capacity that is mostly independent of rate, and redox peaks that exhibit small voltage offsets even at high rates. We also define the structural characteristics necessary for this process, termed intercalation pseudocapacitance, which are a crystalline network that offers two-dimensional transport pathways and little structural change on intercalation. The principal benefit realized from intercalation pseudocapacitance is that high levels of charge storage are achieved within short periods of time because there are no limitations from solid-state diffusion. Thick electrodes (up to 40 μm thick) prepared with T-Nb2O5 offer the promise of exploiting intercalation pseudocapacitance to obtain high-rate charge-storage devices.

  7. Surfactant-cobalt(III) complexes: The impact of hydrophobicity on interaction with HSA and DNA - insights from experimental and theoretical approach.

    Science.gov (United States)

    Veeralakshmi, Selvakumar; Sabapathi, Gopal; Nehru, Selvan; Venuvanalingam, Ponnambalam; Arunachalam, Sankaralingam

    2017-05-01

    To develop surfactant-based metallodrugs, it is very important to know about their hydrophobicity, micelle forming capacity, their interaction with biomacromolecules such as proteins and nucleic acids, and biological activities. Here, diethylenetriamine (dien) and tetradecylamine ligand (TA) based surfactant-cobalt(III) complexes with single chain domain, [Co(dien)(TA)Cl2]ClO4 (1) and double chain domain [Co(dien)(TA)2Cl](ClO4)2 (2) were chosen to study the effect of hydrophobicity on the interaction with human serum albumin and calf thymus DNA. The obtained results showed that (i) single chain surfactant-cobalt(III) complex (1) interact with HSA and DNA via electrostatic interaction and groove binding, respectively; (ii) double chain surfactant-cobalt(III) complex (2) interact with HSA and DNA via hydrophobic interaction and partial intercalation, respectively, due to the play of hydrophobicity by single and double chain domains. Further it is noted that, double chain surfactant-cobalt(III) complex interact strongly with HSA and DNA, compared single chain surfactant-cobalt(III) complex due to their more hydrophobicity nature. DFT and molecular docking studies offer insights into the mechanism and mode of binding towards the molecular target CT-DNA and HSA. Hence, the present findings will create new avenue towards the use of hydrophobic metallodrugs for various therapeutic applications. Copyright © 2017 Elsevier B.V. All rights reserved.

  8. Physical properties of botanical surfactants.

    Science.gov (United States)

    Müller, Lillian Espíndola; Schiedeck, Gustavo

    2017-08-24

    Some vegetal species have saponins in their composition with great potential to be used as natural surfactants in organic crops. This work aims to evaluate some surfactants physical properties of Quillaja brasiliensis and Agave angustifolia, based on different methods of preparation and concentration. The vegetal samples were prepared by drying and grinding, frozen and after chopped or used fresh and chopped. The neutral bar soap was used as a positive control. The drying and grinding of samples were the preparation method that resulted in higher foam column height in both species but Q. brasiliensis was superior to A. angustifolia in all comparisons and foam index was 2756 and 1017 respectively. Critical micelle concentration of Q. brasiliensis was 0.39% with the superficial tension of 54.40mNm(-1) while neutral bar soap was 0.15% with 34.96mNm(-1). Aspects such as genetic characteristics of the species, environmental conditions, and analytical methods make it difficult to compare the results with other studies, but Q. brasiliensis powder has potential to be explored as a natural surfactant in organic farming. Not only the surfactants physical properties of botanical saponins should be taken into account but also its effect on insects and diseases control when decided using them. Copyright © 2017 Elsevier B.V. All rights reserved.

  9. Interactions of Ovalbumin with Ionic Surfactants

    Institute of Scientific and Technical Information of China (English)

    GUO Xia; YAN Hui; GUO Rong

    2008-01-01

    The interactions of ovalbumin (OVA) with one anionic surfactant,sodium dodecyl sulfate (SDS),and two cationic surfactants,dodecyl trimethylammonium bromide (DTAB) and cetyl trimethylammonium bromide (CTAB),in water have been studied through fluorescence and UV-Vis spectroscopies and transmission electronic microscopy,combined with the measurement of conductivity.OVA can increase the critical micelle concentrations (cmc) of SDS and CTAB but has little effect on that of DTAB.The interaction between surfactant monomer and OVA is greater than that between surfactant micelles and OVA.Moreover,SDS can make OVA unfolded while cationic surfactants cannot.

  10. Surfactant gene polymorphisms and interstitial lung diseases

    Directory of Open Access Journals (Sweden)

    Pantelidis Panagiotis

    2001-11-01

    Full Text Available Abstract Pulmonary surfactant is a complex mixture of phospholipids and proteins, which is present in the alveolar lining fluid and is essential for normal lung function. Alterations in surfactant composition have been reported in several interstitial lung diseases (ILDs. Furthermore, a mutation in the surfactant protein C gene that results in complete absence of the protein has been shown to be associated with familial ILD. The role of surfactant in lung disease is therefore drawing increasing attention following the elucidation of the genetic basis underlying its surface expression and the proof of surfactant abnormalities in ILD.

  11. Control of Montmorillonite Surface Coatings on Quartz Grains in Bentonite by Precursor Volcanic Glass

    Science.gov (United States)

    Wendlandt, R. F.; Harrison, W. J.

    2008-12-01

    The pathogenic tendencies of respirable-sized quartz grains may be dependent on inherent characteristics of the quartz as well as external factors. Surface coatings on quartz are of particular interest as they modify both physical and chemical properties of quartz grain surfaces and sequester the grain from contact with reactive lung fluids. Wendlandt et al. (Appl. Geochem. 22, 2007) investigated the surface properties of respirable-sized quartz grains in bentonites and recognized pervasive montmorillonite surface coatings on the quartz that resisted removal by repeated vigorous washings and reaction with HCl. To understand the persistence of montmorillonite coatings on quartz grains of igneous origin, volcanic ash deposits of varying age and degree of alteration to montmorillonite were sampled in Utah, including the distal Lava Creek (c. 0.64 Ma) and Bishop Tuffs (c. 0.74 Ma), and SW Colorado (Conejos Fm, San Juan Volcanic Field) for comparison with commercial grade Cretaceous-age "western" and "southern" bentonites. Quartz grains, hand-picked from these samples, were analyzed using FE-SEM and HRTEM. Continuous coatings of volcanic glass occur on quartz grains from the distal volcanic ash samples. As glass alteration to montmorillonite becomes more extensive, quartz grain surfaces start to display patches of montmorillonite. These patches become continuous in extent on quartz grains from the bentonites. Late precipitation of opal- CT lepispheres is consistent with the alteration reaction for volcanic glass: Volcanic glass + H2O = montmorillonite + SiO2(am) + ions(aq). HRTEM of quartz grains reveals an amorphous surface layer, consistent with a volcanic glass coating. Our results indicate that persistent montmorillonite coatings on quartz grains in bentonites are related to precursor volcanic glass coatings on these grains. The absence of glass coatings on other mineral grains in bentonite (feldspar, biotite) may be a consequence of the presence of strong cleavage

  12. STUDY OF METHYL ORANGE PHOTODEGRADATION USING TiO2-MONTMORILLONITE COMPOSITE

    OpenAIRE

    2015-01-01

    Composite TiO2-montmorillonite (Ti-MMT) has been synthesized with the aim to improve the ability of TiO2 photocatalysts degrade methyl orange. Synthesis of composite made by mixing TiO2 and montmorillonite in ethanol solution, then heated using the furnace at a temperature of 450 °C for 5 hours. TiO2-MMT composites were characterized by FT-IR, XRD and SAA. Test photodegradation activity of TiO2-MMT composites made to dye Methyl Orange 8 mg / L with UV light irradiation time variation and mass...

  13. MECHANICAL BEHAVIOUR OF THERMOPLASTIC STARCH/MONTMORILLONITE/ALUMINA TRIHYDRATE NANOCOMPOSITES

    Directory of Open Access Journals (Sweden)

    FIRNAAZ AHAMED

    2016-09-01

    Full Text Available Thermoplastic starch (TPS is a biodegradable biopolymer that has exhibited great prospects to replace conventional synthetic polymers in commercial applications. However, one of the most critical limitations of TPS is the lack of crucial mechanical properties. This study proposes the novel combination of cassava starch, montmorillonite nanoclay (MMT and alumina trihydrate (ATH in the form of a nanocomposite which is expected to demonstrate improved mechanical properties. The nanocomposites were processed through melt-extrusion in twin-screw extruder where loadings of MMT and ATH were varied between 1 to 6 wt% and 26 to 37 wt%, respectively. The mechanical properties were evaluated through tensile testing according to ASTM D882. The fractured surfaces of the specimens were evaluated using scanning electron microscopy (SEM to further validate the mechanical properties of the nanocomposites. The melt viscosity and processability of the nanocomposites were also evaluated through melt flow index (MFI testing according to ASTM D1238. Presence of MMT and ATH in TPS demonstrated increase in Young’s modulus, maximum tensile stress and decrease in elongation at break up to 57.6 MPa, 5.1 MPa and 39.2%, respectively. In the presence of ATH, increase in loading of MMT continued to improve Young’s modulus and maximum tensile stress while declining elongation at break. Without ATH, MMT was only capable of improving mechanical strength up to a loading of 3 wt% where adverse effects were observed when the loading was further increased to 6 wt%. Increase in loadings of both MMT and ATH, simultaneously were found to depreciate the MFI and thus, the processability of the nanocomposites.

  14. Technical Report-Final-Electrochemistry of Nanostructured Intercalation Hosts

    Energy Technology Data Exchange (ETDEWEB)

    Professor William H. Smyrl, Principal Investigator

    2009-03-09

    We have shown that: (1) Li+ ions are inserted reversibly, without diffusion control, up to the level of at least 4 moles Li+ ions per mole for V2O5, in the aerogel (ARG) form (500 m2/g specific surface area) and aerogel-like (ARG-L) form (200 m2/g specific surface area)(6,7,1,2); (2) polyvalent cations (Al+3, Mg+2, Zn+2) may be intercalated reversibly into V2O5 (ARG) with high capacity (approaching 4 equivalents/mole V2O5 (ARG)) for each (5); (3) dopant cations such as Ag+ and Cu+2 increase the conductivity of V2O5 (XRG) up to three orders of magnitude(3), they are electrochemically active – showing reduction to the metallic-state in parallel to intercalation of Li+ ions – but are not released to the electrolyte upon oxidation and Li+ ion release (Cu+2 ions are reduced to Cu metal and reoxidized to Cu+2 in Li+ ion insertion/release cycles, but the copper ions are not released to the electrolyte over more than 400 cycles of the XRG form); (4) we have shown that Cu+2 ion (dopant) and Zn+2 ions (chemical insertion and dopant) occupy the same intercalation site inV2O5 xerogel and aerogel(4); (5) the reversible intercalation of Zn+2, Mg+2, and Al+3 in the ARG(11) indicates that these cations are “mobile”, but that Cu+2 ions and Ag+ ions are “immobile” in the xerogel, i.e., the latter ions are not exchanged with the electrolyte in Li+ ion intercalation cycling(3).

  15. First principles investigation of copper and silver intercalated molybdenum disulfide

    Science.gov (United States)

    Guzman, D. M.; Onofrio, N.; Strachan, A.

    2017-02-01

    We characterize the energetics and atomic structures involved in the intercalation of copper and silver into the van der Waals gap of molybdenum disulfide as well as the resulting ionic and electronic transport properties using first-principles density functional theory. The intercalation energy of systems with formula (Cu,Ag)xMoS2 decreases with ion concentration and ranges from 1.2 to 0.8 eV for Cu; Ag exhibits a stronger concentration dependence from 2.2 eV for x = 0.014 to 0.75 eV for x = 1 (using the fcc metal as a reference). Partial atomic charge analysis indicates that approximately half an electron is transferred per metallic ion in the case of Cu at low concentrations and the ionicity decreases only slightly with concentration. In contrast, while Ag is only slightly less ionic than Cu for low concentrations, charge transfer reduces significantly to approximately 0.1 e for x = 1. This difference in ionicity between Cu and Ag correlates with their intercalation energies. Importantly, the predicted values indicate the possibility of electrochemical intercalation of both Cu and Ag into MoS2 and the calculated activation energies associated with ionic transport within the gaps, 0.32 eV for Cu and 0.38 eV for Ag, indicate these materials to be good ionic conductors. Analysis of the electronic structure shows that charge transfer leads to a shift of the Fermi energy into the conduction band resulting in a semiconductor-to-metal transition. Electron transport calculations based on non-equilibrium Green's function show that the low-bias conductance increases with metal concentration and is comparable in the horizontal and vertical transport directions. These properties make metal intercalated transition metal di-chalcogenides potential candidates for several applications including electrochemical metallization cells and contacts in electronics based on 2D materials.

  16. An anionic surfactant for EOR applications

    Science.gov (United States)

    Sagir, Muhammad; Tan, Isa M.; Mushtaq, Muhammad

    2014-10-01

    This work is to investigate the new anionic surfactants for the Enhanced Oil Recovery (EOR) application. Sulfonated anionic surfactant was produced by attaching SO3 to an ethoxylated alcohol to increase the performance of the surfactant. Methallyl chloride and ethoxylated alcohol was reacted followed by the reaction with sodium bisulfite to produce anionic sulfonated surfactant in 80.3 % yield. The sulfonation reaction parameters such as reactants mole ratio, reaction temperature and catalyst amount were optimized. The generation and stability of foam from the synthesized surfactant is also tested and results are reported. The synthesized novel surfactant was further investigated for the effect on the CO2 mobility in porous media and the findings are presented here. This in house developed surfactant has a great potential for CO2- EOR applications.

  17. Formation Energies of the Lithium Intercalations in MoS2

    Institute of Scientific and Technical Information of China (English)

    Aiyu LI; Huiying LIU; Zizhong ZHU; Meichun HUANG; Yong YANG

    2006-01-01

    First-principles calculations have been performed to study the lithium intercalations in MoS2. The formation energies, changes of volumes, electronic structures and charge densities of the lithium intercalations in MoS2 are presented. Our calculations show that during lithium intercalations in MoS2, the lithium intercalation formation energies per lithium atom are between 2.5 eV to 3.0 eV, The volume expansions of MoS2 due to lithium intercalations are relatively small

  18. High-Density Chemical Intercalation of Zero-Valent Copper into Bi 2 Se 3 Nanoribbons

    KAUST Repository

    Koski, Kristie J.

    2012-05-09

    A major goal of intercalation chemistry is to intercalate high densities of guest species without disrupting the host lattice. Many intercalant concentrations, however, are limited by the charge of the guest species. Here we have developed a general solution-based chemical method for intercalating extraordinarily high densities of zero-valent copper metal into layered Bi 2Se 3 nanoribbons. Up to 60 atom % copper (Cu 7.5Bi 2Se 3) can be intercalated with no disruption to the host lattice using a solution disproportionation redox reaction. © 2012 American Chemical Society.

  19. Modeling the effect of intercalators on the high-force stretching behavior of DNA

    CERN Document Server

    Schakenraad, Koen; Biebricher, Andreas; Wuite, Gijs; Storm, Cornelis; van der Schoot, Paul

    2015-01-01

    DNA is structurally and mechanically altered by the binding of intercalator molecules. Intercalation strongly affects the force-extension behavior of DNA, in particular the overstretching transition. We present a statistical model that captures all relevant findings of recent force-extension experiments. Two predictions from our model are presented. The first suggests the existence of a novel hyper-stretching regime in the presence of intercalators and the second, a linear dependence of the overstretching force on intercalator concentration, is verified by re-analyzing available experimental data. Our model pins down the physical principles that govern intercalated DNA mechanics, providing a predictive understanding of its limitations and possibilities.

  20. Modification and characterization of montmorillonite clay for the extraction of zearalenone

    Science.gov (United States)

    Hue, Kerri-Ann Alicia

    caused by washing of the clays or exposure to electrolytic solutions. Statistical design of experiments was used to determine the factors most influential during ZEN extraction. Modification by TCMA resulted in an increase in intergallery spacing of ˜0.6nm. TGA and FTIR studies indicated intercalation of organic species within the clay layers. An increase in weight loss proportional to the amount of TCMA added was observed by TGA analysis. In addition to the peaks found in the natural clay, peaks at 2928 cm-1, 2852 cm -1, and 1466 cm-1, which belong to C-H asymmetric stretching, C-H symmetric stretching and -CH2 scissoring respectively characteristic of TCMA were present. The clays developed were able to extract >90% ZEN in vitro at pH 3 and pH7. The factors most important for extraction changed depending on the levels of parameters chosen. Mathematical models were developed that showed the relationship between the factors and the ZEN removal percentage. When exposed to electrolyte solutions ˜1.5pmm of surfactant desorbed from the modified clay.

  1. Dynamics of graphite fiber intercalation: In situ resistivity measurements with a four point probe

    Science.gov (United States)

    Jaworske, D. A.

    1984-01-01

    The dynamics of ferric chloride intercalation of single graphite fibers were studied, in situ, using a four point dc bridge. Measurements before, during and after the intercalation showed that the intercalation occurred within minutes at 200 C. Changes in fiber resistivity after exposure to air suggested hydration of the graphite intercalation compound. Deintercalation of the ferric chloride was initiated at temperatures in excess of 400 C. cycling the intercalant into and out of the graphite fiber gave no improvements in fiber resistivity. The activation energy of the ferric chloride intercalation reaction was found to be 17 + or - 4 kcal/mol 1 consistent with the concept of a preliminary nucleation step in the intercalation reaction.

  2. In Situ Study of CO2 and H2O Partitioning Between Na-Montmorillonite and Variably Wet Supercritical Carbon Dioxide

    Energy Technology Data Exchange (ETDEWEB)

    Loring, John S.; Ilton, Eugene S.; Chen, Jeffrey; Thompson, Christopher J.; Martin, Paul F.; Benezeth, Pascale; Rosso, Kevin M.; Felmy, Andrew R.; Schaef, Herbert T.

    2014-06-03

    Shale formations play fundamental roles in large-scale geologic carbon sequestration (GCS) aimed primarily to mitigate climate change, and in smaller-scale GCS targeted mainly for CO2-enhanced gas recovery operations. In both technologies, CO2 is injected underground as a supercritical fluid (scCO2), where interactions with shale minerals could influence successful GCS implementation. Reactive components of shales include expandable clays, such as montmorillonites and mixed-layer illite/smectite clays. In this work, we used in situ X-ray diffraction (XRD) and in situ infrared (IR) spectroscopy to investigate the swelling/shrinkage and water/CO2 sorption of a pure montmorillonite, Na-SWy-2, when the clay is exposed to variably hydrated scCO2 at 50 °C and 90 bar. Measured interlayer spacings and sorbed water concentrations at varying levels of scCO2 hydration are similar to previously reported values measured in air at ambient pressure over a range of relative humidities. IR spectra show evidence of both water and CO2 intercalation, and variations in peak shapes and positions suggest multiple sorbed types with distinct chemical environments. Based on the intensity of the asymmetric CO stretching band of the CO2 associated with the Na-SWy-2, we observed a significant increase in sorbed CO2 as the clay expands from a 0W to a 1W state, suggesting that water props open the interlayer so that CO2 can enter. However, as the clay transitions from a 1W to a 2W state, CO2 desorbs sharply. These observations were placed in the context of two conceptual models concerning hydration mechanisms for expandable clays and were also discussed in light of recent theoretical studies on CO2-H2O-clay interactions. The swelling/shrinkage of expandable clays could affect solid volume, porosity, and permeability of shales. Consequently, the results from this work could aid predictions of shale caprock integrity in large-scale GCS, as well as methane transmissivity in enhanced gas recovery

  3. Characterization of sodium bentonites: effect of treatment with ammonium salt- free organic surfactant; Caracterizacao de bentonitas sodicas: efeito do tratamento com surfactante organico livre de sal de amonio

    Energy Technology Data Exchange (ETDEWEB)

    Morita, R. Y.; Barbosa, R. V.; Kloss, J.R., E-mail: julianaweber@utfpr.edu.br [Universidade Tecnologica Federal do Parana (UTFPR), Curitiba, PR (Brazil). Dartamento de Quimica e Biologia

    2015-07-15

    Bentonite, which the main clay mineral is montmorillonite, are commercially attractive because of its abundance in nature. The clays can be modified by ion exchange reactions of ions contained in the interlayer region with cationic surfactants that include ammonium or phosphonium salts. The clays origin and the type of surfactants (modifiers) are the main factors in the alteration of physical and chemical properties of these materials. This study aims to characterize and compare the results of natural bentonite commercially available and the effect of treatments with quaternary ammonium salt and an organic compound free of ammonium salt. The FTIR and XRD results indicate the process of organophilization of clays after treatment with the surfactants. These treatments have altered the average particle size, suggesting the formation of agglomerates, which was showed in the SEM images. The results of surface area and particle size data indicated the presence of larger particles. Although the two surfactants have shown similarities in the investigated properties, the organoclays free of ammonium salt are more promising in terms of its use as well as for their preparation and solubility. (author)

  4. Peptide chain elongation: A possible role of montmorillonite in prebiotic synthesis of protein precursors

    Science.gov (United States)

    Bujdák, Juraj; Faybíková, Katarína; Eder, Artur; Yongyai, Yongyos; Rode, Bernd M.

    1995-10-01

    Several studies have proven the ability of montmorillonite to catalyse amino acid condensation under assumed prebiotic conditions, simulating wetting-drying cycles. In this work, the oligomerization of short peptides gly2, gly3, gly4 and ala2 on Ca-and Cu-montmorillonite in drying-wetting cycles at 80 °C was studied. The catalytic effect of montmorillonite was found to be much higher than in the case of glycine oligomerization. From gly2 after 3 weeks, 10% oligomers (up to gly6, with gly3 as main products) are formed. Gly3 and gly4 give higher oligomers even after 1 cycle. Ala2 produces both ala3 and ala4, whereas ala does not produce any oligomers under these conditions. Heteroologomerization was observed: ala-gly-gly is formed from ala and gly2. Much higher yields are obtained using Ca-montmorillonite, because copper (II) oxidizes organic molecules. The influence of the reaction mechanism on the preferential oligomerization of oligopeptides is discussed.

  5. Calcium montmorillonite clay for the reduction of aflatoxin residues in milk and dairy products

    Science.gov (United States)

    In this study, dairy cows were treated with calcium montmorillonite clay (NovaSil Plus (NSP); BASF Corp., Ludwigshaven, Germany) in a replicated 5x5 Latin square design. The primary objectives were to determine if milk composition was altered following ingestion of NSP, and to investigate the abili...

  6. KF-Montmorillonite-catalyzed Michael Addition Reaction of Malononitrile to α,β-Unsaturated Ketones

    Institute of Scientific and Technical Information of China (English)

    SHI Daqing; WU Nan; ZHUANG Qiya

    2009-01-01

    The Michael addition reaction of α,β-unsaturated ketones with malononitrile catalyzed by KF-montmorillonite was investigated. It was interesting to note that at different reaction temperatures the addition and cycloaddition re-action products were obtained. This method has the advantages of good yields, mild reaction conditions, easy work-up and inexpensive reagents over the existing procedures.

  7. Green Synthesis of Carvenone by Montmorillonite-Catalyzed Isomerization of 1,2-Limonene Oxide

    DEFF Research Database (Denmark)

    Nguyen, Thao-Tran Thi; Chau, Duy-Khiem Nguyen; Duus, Fritz;

    2013-01-01

    Montmorillonite was considered as a good heterogeneous catalyst for the isomerization of 1,2-limonene oxide into car-venone under solvent-free condition. Both conventional heating and green activations were tested in this research. The microwave-assisted isomerization afforded carvenone in high...

  8. Properties and Semicrystalline Structure Evolution of Polypropylene/Montmorillonite Nanocomposites under Mechanical Load

    DEFF Research Database (Denmark)

    Stribeck, Norbert; Zeinolebadi, Ahmad; Ganjaee Sari, Morteza;

    2012-01-01

    Small-angle X-ray scattering (SAXS) monitors tensile and load-cycling tests of metallocene isotactic polypropylene (PP), a blend of PP and montmorillonite (MMT), and two block copolymer compatibilized PP/MMT nanocomposites. Mechanical properties of the materials are similar, but the semicrystalline...

  9. Acylation of aromatic alcohols and phenols over InCl3/montmorillonite K-10 catalysts

    Indian Academy of Sciences (India)

    Vasant R Choudhary; Kailash Y Patil; Suman K Jana

    2004-03-01

    Montmorillonite K-10 clay supported InCl3 is a highly active catalyst for the acylation of aromatic alcohols and phenols with different acyl chlorides. This catalyst can be reused in reactions a number of times without very significant loss of catalytic activity.

  10. Montmorillonite Functionalized with Pralidoxime as a Material for Chemical Protection against Organophosphorous Compounds

    Science.gov (United States)

    2011-03-25

    binds to organophosphate - inactivated acetylcholinesterase. It is used by the military to combat poisoning by acetylcholinesterase inhibitors (nerve...montmorillonite K-10; pyridine-2-aldoxime methiodide; functionalization; organophosphate hydrolysis; protective barrier Lev Bromberg, Christine M. Straut...functionalization, organophosphate hydrolysis, protective barrier 1480 dx.doi.org/10.1021/am200041e |ACS Appl. Mater. Interfaces 2011, 3, 1479–1484 ACS

  11. Influence Of Fine-Grained Montmorillonite On Microfungal Pellets Growth In Aqueous Suspensions

    Directory of Open Access Journals (Sweden)

    Jesenák Karol

    2015-06-01

    Full Text Available The paper presents an inhibition effect of clay mineral – montmorillonite – on the growth of microscopic filamentous fungus Aspergillus niger in the aqueous solution. The significant reduction in growth of the final size of spherical fungal pellets as well as total amount of produced microbial biomass was found out. Within the observed range of additions of clay mineral of 1, 5, 10, 15 and 20 g in the total volume of the 80 ml suspension, this size was in indirect relation to the weight of montmorillonite. However, the most significant inhibition effect was observed at the lowest concentration of the sorbent (1 g. Microscopic analysis of pellets referred to the presence of mineral particles in their pore structure and the distribution of particles in the spatial structure of fungal hyphae was variable. The experiment clearly demonstrated an inhibition effect of montmorillonite. This inhibition could be answered by the experiments focused on the detection of the influence of size and shape of inorganic sorption particles together with the influence of the physicochemical properties of its surface. It could be stated that the simultaneous application of the microscopic fungus Aspergillus niger and the clay mineral montmorillonite for decontamination of waste waters should be disadvantage due to their interaction if compared with the decontamination based on bioaccumulation and sorption separately.

  12. Alkylation of Catechol with tert-Butyl Alcohol Catalyzed by Mesoporous Acidic Montmorillonite Heterostructure Catalysts

    Institute of Scientific and Technical Information of China (English)

    周春晖; 葛忠华; 李小年; 童东绅; 李庆伟; 郭红强

    2004-01-01

    The liquid phase alkylation of catechol with tert-butyl alcohol to produce 4-tert-butyl catechol (4-TBC) was carried out over MCM-41, HZSM-5, H-exchanged montmorillonite and novel acidic porous montmorillonite heterostructures (PMHs). Upon all catalysts tested, 4-TBC is the main product and 3-tert-butyl catechol (3-TBC) and 3,5-di-tert-butyl catechol are the side products. The synthetic PMHs showed higher conversion of catechol and better selectivity to 4-TBC compared to other solid acid catalysts tested. Over the PMHs derived from H-exchanged montmorillonite through template extraction processes, the suitable reaction temperature is ca 410 K, the ratio of catechol to tert-butyl alcohol is 1:2. Increasing the amount of catalyst (lower weight hourly space velocity) can improve the conversion of catechol and influence the selectivity slightly. The reasonable reaction time is ca 8 h.The type and strength of acidity of H-montmorillonite and PMH were determined by pyridine adsorption FT-IR and ammonia temperature-programmed desorption techniques. The medium and strong acid sites are conducive to producing 4-TBC and the weak acid sites to facilitating the 3-TBC formation. The differences between the PMHs from calcination and those fi'om extraction are attributed to proton migration and acidity change in the gallery surface.

  13. Preparation and Properties of Pillared Montmorillonite by Polyhydroxyl-aluminum-manganese Cations

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    Al-Mn-pillared montmorillonite(AMPM) was prepared by using the artificial Na-montmorillonite from the Qingfengshan bentonite mine as starting materials mixed with Al-Mn pillaring solutions at different Al/Mn molar ratios(R).The basal spacing and specific surface area of the materials were increased significantly compared with untreated clays.When R=0.5, the d(001) value and specific surface area of pillared montmorillonite were 1.8987 nm and 146.01 m2 g-1,respectively.The thermal stability was determined using calcined tests,X-ray diffraction(XRD) analysis, thermal gravimetry and differential thermal analysis(TG-DTA).The materials formed at initial R=0.5 exhibited a high stability,the basal interlayer spacing was stabilized at 1.7859 nm after calcined for 2 h at 300℃.The adsorption behavior of the materials was studied by adsorption experiments.The results show the AMPM and calcined Al-Mn-pillared montmorillonite(CAMPM) exhibit a strong capacity of adsorbing the Zn(II) in aqueous solution at pH 10.0.

  14. Synthesis of graphene oxide-intercalated alpha-hydroxides by metathesis and their decomposition to graphene/metal oxide composites

    OpenAIRE

    2010-01-01

    Graphene oxide-intercalated alpha-metal hydroxides were prepared using layers from the delaminated colloidal dispersions of cetyltrimethylammonium-intercalated graphene oxide and dodecylsulfate-intercalated alpha-hydroxide of nickel/cobalt as precursors. The reaction of the two dispersions leads to de-intercalation of the interlayer ions from both the layered solids and the intercalation of the negatively charged graphene oxide sheets between the positively charged layers of the alpha-hydroxi...

  15. Surfactants in tribology, v.3

    CERN Document Server

    Biresaw, Girma

    2013-01-01

    The manufacture and use of almost every consumer and industrial product rely on application of advanced knowledge in surface science and tribology. These two disciplines are of critical importance in major economic sectors, such as mining, agriculture, manufacturing (including metals, plastics, wood, computers, MEMS, NEMS, appliances), construction, transportation, and medical instruments, transplants, and diagnostic devices. An up-to-date reference with contributions by experts in surface science and tribology, Surfactants in Tribology, Volume 3 discusses some of the underlying tribological a

  16. Anaerobic Biodegradation of Detergent Surfactants

    OpenAIRE

    Erich Jelen; Ute Merrettig-Bruns

    2009-01-01

    Detergent surfactantscan be found in wastewater in relevant concentrations. Most of them are known as ready degradable under aerobic conditions, as required by European legislation. Far fewer surfactants have been tested so far for biodegradability under anaerobic conditions. The natural environment is predominantly aerobic, but there are some environmental compartments such as river sediments, sub-surface soil layer and anaerobic sludge digesters of wastewater treatment plants which have str...

  17. Pictet-Spengler condensation reactions catalyzed by a recyclable H~+-montmorillonite as a heterogeneous BrΦnsted acid

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    Catalytic performance of different cation-exchanged montmorillonite clays has been investigated in the Pictet-Spengler C-C bond forming reaction.H+-Montmorillonite was found to be a very efficient and reusable catalyst for the endo cyclization of β-phenylethylamine derivatives with aldehydes under solvent-free conditions.In addition,an aqueous condensation version for the synthesis of tetrahydro-β-carbolines using the H+-montmorillonite catalyst has been developed.In these environmentally friendly processes,the use of organic solvents was avoided and the catalyst was recycled with maintenance of high catalytic activity.

  18. Fe(III/TiO2-Montmorillonite Photocatalyst in Photo-Fenton-Like Degradation of Methylene Blue

    Directory of Open Access Journals (Sweden)

    Is Fatimah

    2015-01-01

    Full Text Available A photodegradation process of methylene blue (MB in aqueous solution using Fe(III/TiO2-montmorillonite photocatalyst is presented. The photocatalyst material was prepared using Indonesian natural montmorillonite in TiO2 pillarization process followed by Fe(III ion exchange. Kinetic study on MB degradation was conducted and evaluated by three kinetic models: the pseudo-first- and second-order equations and the Elovich equation. From the results, it is concluded that the degradation under the photo-Fenton-like process utilizing Fe(III/TiO2-montmorillonite photocatalyst conformed to the Elovich kinetic model.

  19. Controlling the photoconductivity: Graphene oxide and polyaniline self assembled intercalation

    Energy Technology Data Exchange (ETDEWEB)

    Vempati, Sesha, E-mail: svempati01@qub.ac.uk [UNAM-National Nanotechnology Research Centre, Bilkent University, Ankara 06800 (Turkey); Ozcan, Sefika [UNAM-National Nanotechnology Research Centre, Bilkent University, Ankara 06800 (Turkey); Department of Polymer Science and Technology, Middle East Technical University, Ankara 06800 (Turkey); Uyar, Tamer, E-mail: uyar@unam.bilkent.edu.tr [UNAM-National Nanotechnology Research Centre, Bilkent University, Ankara 06800 (Turkey); Institute of Materials Science and Nanotechnology, Bilkent University, Ankara 06800 (Turkey)

    2015-02-02

    We report on controlling the optoelectronic properties of self-assembled intercalating compound of graphene oxide (GO) and HCl doped polyaniline (PANI). Optical emission and X-ray diffraction studies revealed a secondary doping phenomenon of PANI with –OH and –COOH groups of GO, which essentially arbitrate the intercalation. A control on the polarity and the magnitude of the photoresponse (PR) is harnessed by manipulating the weight ratios of PANI to GO (viz., 1:1.5 and 1:2.2 are abbreviated as PG1.5 and PG2.2, respectively), where ±PR = 100(R{sub Dark} – R{sub UV-Vis})/R{sub Dark} and R corresponds to the resistance of the device in dark or UV-Vis illumination. To be precise, the PR from GO, PANI, PG1.5, and PG2.2 are +34%, −111%, −51%, and +58%, respectively.

  20. Nanostructural origin of giant Rashba effect in intercalated graphene

    Science.gov (United States)

    Krivenkov, M.; Golias, E.; Marchenko, D.; Sánchez-Barriga, J.; Bihlmayer, G.; Rader, O.; Varykhalov, A.

    2017-09-01

    To enhance the spin-orbit interaction in graphene by a proximity effect without compromising the quasi-free-standing dispersion of the Dirac cones means balancing the opposing demands for strong and weak graphene-substrate interaction. So far, only the intercalation of Au under graphene/Ni(1 1 1) has proven successful, which was unexpected since graphene prefers a large separation (˜3.3~{\\mathringA} ) from a Au monolayer in equilibrium. Here, we investigate this system and find the solution in a nanoscale effect. We reveal that the Au largely intercalates as nanoclusters. Our density functional theory calculations show that the graphene is periodically stapled to the Ni substrate, and this attraction presses graphene and Au nanoclusters together. This, in turn, causes a Rashba effect of the giant magnitude observed in experiment. Our findings show that nanopatterning of the substrate can be efficiently used for engineering of spin-orbit effects in graphene.

  1. Phase Separation Dynamics in Isotropic Ion-Intercalation Particles

    CERN Document Server

    Zeng, Yi

    2013-01-01

    Lithium-ion batteries exhibit complex nonlinear dynamics, resulting from diffusion and phase transformations coupled to ion intercalation reactions. Using the recently developed Cahn-Hilliard reaction (CHR) theory, we investigate a simple mathematical model of ion intercalation in a spherical solid nanoparticle, which predicts transitions from solid-solution radial diffusion to two-phase shrinking-core dynamics. This general approach extends previous Li-ion battery models, which either neglect phase separation or postulate a spherical shrinking-core phase boundary, by predicting phase separation only under appropriate circumstances. The effect of the applied current is captured by generalized Butler-Volmer kinetics, formulated in terms of diffusional chemical potentials, and the model consistently links the evolving concentration profile to the battery voltage. We examine sources of charge/discharge asymmetry, such as asymmetric charge transfer and surface "wetting" by ions within the solid, which can lead to...

  2. Induced magnetism in transition metal intercalated graphitic systems

    KAUST Repository

    Kaloni, Thaneshwor P.

    2011-10-26

    We investigate the structure, chemical bonding, electronic properties, and magnetic behavior of a three-dimensional graphitic network in aba and aaa stacking with intercalated transition metal atoms (Mn, Fe, Co, Ni, and Cu). Using density functional theory, we find induced spin-polarization of the C atoms both when the graphene sheets are aba stacked (forming graphite) and aaa stacked (resembling bi-layer graphene). The magnetic moment induced by Mn, Fe, and Co turns out to vary from 1.38 μB to 4.10 μB, whereas intercalation of Ni and Cu does not lead to a magnetic state. The selective induction of spin-polarization can be utilized in spintronic and nanoelectronic applications.

  3. Abl suppresses cell extrusion and intercalation during epithelium folding.

    Science.gov (United States)

    Jodoin, Jeanne N; Martin, Adam C

    2016-09-15

    Tissue morphogenesis requires control over cell shape changes and rearrangements. In the Drosophila mesoderm, linked epithelial cells apically constrict, without cell extrusion or intercalation, to fold the epithelium into a tube that will then undergo epithelial-to-mesenchymal transition (EMT). Apical constriction drives tissue folding or cell extrusion in different contexts, but the mechanisms that dictate the specific outcomes are poorly understood. Using live imaging, we found that Abelson (Abl) tyrosine kinase depletion causes apically constricting cells to undergo aberrant basal cell extrusion and cell intercalation. abl depletion disrupted apical-basal polarity and adherens junction organization in mesoderm cells, suggesting that extruding cells undergo premature EMT. The polarity loss was associated with abnormal basolateral contractile actomyosin and Enabled (Ena) accumulation. Depletion of the Abl effector Enabled (Ena) in abl-depleted embryos suppressed the abl phenotype, consistent with cell extrusion resulting from misregulated ena Our work provides new insight into how Abl loss and Ena misregulation promote cell extrusion and EMT.

  4. Rational design of a triple helix-specific intercalating ligand.

    Science.gov (United States)

    Escudé, C; Nguyen, C H; Kukreti, S; Janin, Y; Sun, J S; Bisagni, E; Garestier, T; Hélène, C

    1998-03-31

    DNA triple helices offer new perspectives toward oligonucleotide-directed gene regulation. However, the poor stability of some of these structures might limit their use under physiological conditions. Specific ligands can intercalate into DNA triple helices and stabilize them. Molecular modeling and thermal denaturation experiments suggest that benzo[f]pyrido[3, 4-b]quinoxaline derivatives intercalate into triple helices by stacking preferentially with the Hoogsteen-paired bases. Based on this model, it was predicted that a benzo[f]quino[3,4-b]quinoxaline derivative, which possesses an additional aromatic ring, could engage additional stacking interactions with the pyrimidine strand of the Watson-Crick double helix upon binding of this pentacyclic ligand to a triplex structure. This compound was synthesized. Thermal denaturation experiments and inhibition of restriction enzyme cleavage show that this new compound can indeed stabilize triple helices with great efficiency and specificity and/or induce triple helix formation under physiological conditions.

  5. Electrochemical Doping of Halide Perovskites with Ion Intercalation.

    Science.gov (United States)

    Jiang, Qinglong; Chen, Mingming; Li, Junqiang; Wang, Mingchao; Zeng, Xiaoqiao; Besara, Tiglet; Lu, Jun; Xin, Yan; Shan, Xin; Pan, Bicai; Wang, Changchun; Lin, Shangchao; Siegrist, Theo; Xiao, Qiangfeng; Yu, Zhibin

    2017-01-24

    Halide perovskites have recently been investigated for various solution-processed optoelectronic devices. The majority of studies have focused on using intrinsic halide perovskites, and the intentional incoporation of dopants has not been well explored. In this work, we discovered that small alkali ions, including lithium and sodium ions, could be electrochemically intercalated into a variety of halide and pseudohalide perovskites. The ion intercalation caused a lattice expansion of the perovskite crystals and resulted in an n-type doping of the perovskites. Such electrochemical doping improved the conductivity and changed the color of the perovskites, leading to an electrochromism with more than 40% reduction of transmittance in the 450-850 nm wavelength range. The doped perovskites exhibited improved electron injection efficiency into the pristine perovskite crystals, resulting in bright light-emitting diodes with a low turn-on voltage.

  6. Superconductivity in the Graphite Intercalation Compound BaC(6).

    Science.gov (United States)

    Heguri, Satoshi; Kawade, Naoya; Fujisawa, Takumi; Yamaguchi, Akira; Sumiyama, Akihiko; Tanigaki, Katsumi; Kobayashi, Mototada

    2015-06-19

    Among many two-dimensional (2D) high T(C) superconductors, graphite intercalation compounds (GICs) are the most famous intercalation family, which are classified as typical electron-phonon mediated superconductors. We show unambiguous experimental facts that BaC(6), the superconductivity of which has been missing for many years so far among various alkaline earth metal (Ca, Sr, and Ba) intercalted GICs, exhibits superconductivity at T(C)=65  mK. By adding this finding as the additional experimental point, a complete figure displaying the relationship between T(C) and interlayer distance (d) for GICs is now provided, and their possible superconducting mechanisms raised so far are revisited. The present study settles a long-running debate between theories and experiments on the superconductivity in the first stage GICs.

  7. Surfactant inhibition in acute respiratory failure : consequences for exogenous surfactant therapy

    NARCIS (Netherlands)

    E.P. Eijking (Eric)

    1993-01-01

    textabstractThe neonatal respiratory distress syndrome (RDS) is characterized by immaturity of the lung, resulting in relative or absolute absence of pulmonary surfactant. Worldwide, neonates suffering from RDS have been treated successfully with exogenous surfactant preparations. Currently, exogeno

  8. Molecular Dynamics Simulations of Carbon Dioxide, Methane, and Their Mixture in Montmorillonite Clay Hydrates

    KAUST Repository

    Kadoura, Ahmad Salim

    2016-05-26

    Molecular dynamics simulations were carried out to study the structural and transport properties of carbon dioxide, methane, and their mixture at 298.15 K in Na-montmorillonite clay in the presence of water. The simulations show that, the self-diffusion coefficients of pure CO2 and CH4 molecules in the interlayers of Na-montmorillonite decrease as their loading increases, possibly because of steric hindrance. The diffusion of CO2 in the interlayers of Na-montmorillonite, at constant loading of CO2, is not significantly affected by CH4 for the investigated CO2/CH4 mixture compositions. We attribute this to the preferential adsorption of CO2 over CH4 in Na-montmorillonite. While the presence of adsorbed CO2 molecules, at constant loading of CH4, very significantly reduces the self-diffusion coefficients of CH4, and relatively larger decrease in those diffusion coefficients are obtained at higher loadings. The preferential adsorption of CO2 molecules to the clay surface screens those possible attractive surface sites for CH4. The competition between screening and steric effects leads to a very slight decrease in the diffusion coefficients of CH4 molecules at low CO2 loadings. The steric hindrance effect, however, becomes much more significant at higher CO2 loadings and the diffusion coefficients of methane molecules significantly decrease. Our simulations also indicate that, similar effects of water on both carbon dioxide and methane, increase with increasing water concentration, at constant loadings of CO2 and CH4 in the interlayers of Na-montmorillonite. Our results could be useful, because of the significance of shale gas exploitation and carbon dioxide storage.

  9. Aflatoxin B1 adsorption by the natural aluminosilicates - concentrate of montmorillonite and zeolite

    Directory of Open Access Journals (Sweden)

    Marković Marija A.

    2016-01-01

    Full Text Available Aflatoxin B1 adsorption by the concentrate of bentonite clay - montmorillonite and the natural zeolite - clinoptilolite and was investigated at the initial toxin concentration 4 ppm, with different amonunts of solid phase in suspension (10, 5, 2 and 1 mg/10 mL and different pH values - 3, 7 and 9. Results indicated that for both minerals, decreasing the amount of solid phase in suspension, decrease the amount of active sites relevant for adsorption of aflatoxin B1. Thus, for concentrate of montnorillonite, at the lowest level of solid phase in suspension (1 mg/10 mL, aflatoxin B1 adsorption indexes were 97% at pH 3, 88% at pH 7 and 82% at pH 9, while for the natural zeolite, adsorption of toxin was 9% at pH 3 and 7% at pH 7 and 9. Since inorganic cations in minerals are mainly responsible for aflatoxin B1 adsorption, even the natural zeolite - clinoptilite has much higher cation exchange capacity (the content of inorganic exchangeable cations compared to the concentrate of montmorillonite, adsorption of aflatoxin B1 by this mineral is much lower. Comparing the molecular dimensions of aflatoxin B1 molecule with the dimension of channels of clinoptilolite and interlamellar space of montmorillonite it is obvious that this toxin is adsorbed only at the external surface of clinoptilolite while in the montmorillonite all active sites are equally available for its adsorption. Thus, the concentrate of montmorillonite posess by higher adsorption capacity for aflatoxin B1. Results presented in this paper confirmed the fact the differences in the structure of minerals led to their different efficiency for adsorption of aflatoxin B1. Mineralogical and chemical composition, determination of cation exchange capacity, etc., are very important parameters influencing the effectiveness of minerals as aflatoxin B1 adsorbents. [Projekat Ministarstva nauke Republike Srbije, br. 451-03-2802-IP Tip1/142, br. 172018 i br. 34013

  10. Curie and Pauli Spins in Lithium Intercalated MCMB

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    The ESR signal of lithium intercalated MCMB can be well simulated by combination of a Lorentz curve and a Gauss curve. The ESR intensity of the Lorentz component is essentially independent of temperature while the Gauss component shows a linear change with the reciprocal of temperature, indicative of Pauli spin and Curie spin, respectively. The former is probably associated with the ordered (graphitized) structures while the latter with the disordered structures in the sample.

  11. Intercalation of Epinephrine with Calf-thymus ds-DNA

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    A strong interaction between double stranded calf-thymus DNA (ds-DNA) and epinephrine but no interaction between single stranded calf-thymus DNA (ss-DNA) and epinephrine were observed by the use of UV-spectroscopy and cyclic voltammetry. It is suggested that the interaction leads to an intercalation of EP molecules into the groove of ds-DNA and the formation of ds-DNA(EP)n complex.

  12. Preferential Intercalation of Pyridinedicarboxylates into Layered Double Hydroxides

    Institute of Scientific and Technical Information of China (English)

    李蕾; 莫丹; 陈大舟

    2005-01-01

    Intercalation of 2,3-,2,4-,2,5-,2,6-,3,4-,or3,5-pyridincdicarboxylate into the layered double hydroxide (LDH),[Mg0.73AIo.27(OH)2](CO3)0.14*1.34H2O was carried out by the reconstruction method in the molar ratio of organic acid: calcined LDH=3:8, in 80% alcoholic aqueous solution at 70℃. Selective reaction was observed in com-petitive experiments involving an equal concentration pairs of acids. The preference order of the organic acids intercalated into the Mg-Al-LDH was found to be in the order of 2,3-pyridinedicarboxylate>2,5-pyridinedicarboxylate>2,4-pyridinedicarboxylate>3,5-pyridinedicarboxylate>3,4-pyridinedicarboxylate>2,6-pyridinedic arboxylate. The structures of the intercalates formed by the reaction of six guests with Mg-Al-LDH were characterized by X-ray diffraction, infrared and thermogravimetry techniques. And the charge density on the oxygens of each of the carboxylate groups for the six anions was investigated utilizing ab initio (HF/6-31G) method by G98w. From the X-ray diffraction data, the guest size and the charge density of the oxygens of the guest, the orientation of 2,3-,2,4-,2,5-,2,6-,3,4-, or 3,5-pyridinedicarboxylate anions between the layers was determined and the preferential intercalation mechanism was discussed. These results indicate the possibility of a molecular recognition ability of LDH and it would be exploited for the chemical separation of some anions from solution.

  13. Transport study of electrochemically decorated and intercalated graphene

    Science.gov (United States)

    Efetov, Dmitri K.; Mak, Kin Fai; Guo, Yinsheng; Heinz, Tony F.; Brus, Louis; Kim, Philip

    2012-02-01

    Due to the surface-only properties of graphene, the decoration and/or intercalation of single, bi- and multi-layer graphene with foreign atoms can severely modify its electronic interactions, similar to those observed in its 3D counterpart the graphite intercalation compounds. Supported by a highly increased density of state due to a strong charge transfer above 10^14 cm-2 into the graphene π-bands, certain adatoms are expected to induce strong electronic interactions to the graphenes own Dirac fermions, where theoretical predictions reach from the Kondo-effect and magnetism to as far as superconductivity in graphene. In this study we will present evidence of specific adsorption and intercalation of diverse atomic species by electrochemical means. We will present a detailed transport study, including resistivity-, Hall- and magneto-resistivity measurements of single-, bi- and multi-layer graphene devices which were subjected to electrochemical doping by a variety of electrolytes and ionic species such as Li^+, ClO4^-, Cs^+, Ca^2+, etc.

  14. Reversible Intercalation of Fluoride-Anion Receptor Complexes in Graphite

    Science.gov (United States)

    West, William C.; Whitacre, Jay F.; Leifer, Nicole; Greenbaum, Steve; Smart, Marshall; Bugga, Ratnakumar; Blanco, Mario; Narayanan, S. R.

    2007-01-01

    We have demonstrated a route to reversibly intercalate fluoride-anion receptor complexes in graphite via a nonaqueous electrochemical process. This approach may find application for a rechargeable lithium-fluoride dual-ion intercalating battery with high specific energy. The cell chemistry presented here uses graphite cathodes with LiF dissolved in a nonaqueous solvent through the aid of anion receptors. Cells have been demonstrated with reversible cathode specific capacity of approximately 80 mAh/g at discharge plateaus of upward of 4.8 V, with graphite staging of the intercalant observed via in situ synchrotron X-ray diffraction during charging. Electrochemical impedance spectroscopy and B-11 nuclear magnetic resonance studies suggest that cointercalation of the anion receptor with the fluoride occurs during charging, which likely limits the cathode specific capacity. The anion receptor type dictates the extent of graphite fluorination, and must be further optimized to realize high theoretical fluorination levels. To find these optimal anion receptors, we have designed an ab initio calculations-based scheme aimed at identifying receptors with favorable fluoride binding and release properties.

  15. Selective and low temperature transition metal intercalation in layered tellurides

    Science.gov (United States)

    Yajima, Takeshi; Koshiko, Masaki; Zhang, Yaoqing; Oguchi, Tamio; Yu, Wen; Kato, Daichi; Kobayashi, Yoji; Orikasa, Yuki; Yamamoto, Takafumi; Uchimoto, Yoshiharu; Green, Mark A.; Kageyama, Hiroshi

    2016-12-01

    Layered materials embrace rich intercalation reactions to accommodate high concentrations of foreign species within their structures, and find many applications spanning from energy storage, ion exchange to secondary batteries. Light alkali metals are generally most easily intercalated due to their light mass, high charge/volume ratio and in many cases strong reducing properties. An evolving area of materials chemistry, however, is to capture metals selectively, which is of technological and environmental significance but rather unexplored. Here we show that the layered telluride T2PTe2 (T=Ti, Zr) displays exclusive insertion of transition metals (for example, Cd, Zn) as opposed to alkali cations, with tetrahedral coordination preference to tellurium. Interestingly, the intercalation reactions proceed in solid state and at surprisingly low temperatures (for example, 80 °C for cadmium in Ti2PTe2). The current method of controlling selectivity provides opportunities in the search for new materials for various applications that used to be possible only in a liquid.

  16. Molecular Intercalation and Cohesion of Organic Bulk Heterojunction Photovoltaic Devices

    KAUST Repository

    Bruner, Christopher

    2013-01-17

    The phase separated bulk heterojunction (BHJ) layer in BHJ polymer:fullerene organic photovoltaic devices (OPV) are mechanically weak with low values of cohesion. Improved cohesion is important for OPV device thermomechanical reliability. BHJ devices are investigated and how fullerene intercalation within the active layer affects cohesive properties in the BHJ is shown. The intercalation of fullerenes between the side chains of the polymers poly(3,3″′-didocecyl quaterthiophene) (PQT-12) and poly(2,5-bis(3-hexadecylthiophen-2-yl)thieno[3,2-b]thiophene (pBTTT) is shown to enhance BHJ layer cohesion. Cohesion values range from ≈1 to 5 J m -2, depending on the polymer:fullerene blend, processing conditions, and composition. Devices with non-intercalated BHJ layers are found to have significantly reduced values of cohesion. The resulting device power conversion efficiencies (PCE) are also investigated and correlated with the device cohesion. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  17. Incommensurate Graphene Foam as a High Capacity Lithium Intercalation Anode

    Science.gov (United States)

    Paronyan, Tereza M.; Thapa, Arjun Kumar; Sherehiy, Andriy; Jasinski, Jacek B.; Jangam, John Samuel Dilip

    2017-01-01

    Graphite’s capacity of intercalating lithium in rechargeable batteries is limited (theoretically, 372 mAh g‑1) due to low diffusion within commensurately-stacked graphene layers. Graphene foam with highly enriched incommensurately-stacked layers was grown and applied as an active electrode in rechargeable batteries. A 93% incommensurate graphene foam demonstrated a reversible specific capacity of 1,540 mAh g‑1 with a 75% coulombic efficiency, and an 86% incommensurate sample achieves above 99% coulombic efficiency exhibiting 930 mAh g‑1 specific capacity. The structural and binding analysis of graphene show that lithium atoms highly intercalate within weakly interacting incommensurately-stacked graphene network, followed by a further flexible rearrangement of layers for a long-term stable cycling. We consider lithium intercalation model for multilayer graphene where capacity varies with N number of layers resulting LiN+1C2N stoichiometry. The effective capacity of commonly used carbon-based rechargeable batteries can be significantly improved using incommensurate graphene as an anode material.

  18. Novel isoxazole polycyclic aromatic hydrocarbons as DNA-intercalating agents.

    Science.gov (United States)

    Rescifina, Antonio; Varrica, Maria Giulia; Carnovale, Caterina; Romeo, Giovanni; Chiacchio, Ugo

    2012-05-01

    The third generation of isoxazole polycyclic aromatic hydrocarbons, acting as DNA-intercalator agents and possessing the binding constants in the range 10(4)-10(5) M(-1), in order to easily diffuse targeting remotely implanted tumors, has been synthesized in good yields according to the 1,3-dipolar cycloaddition methodology. The structure of the obtained cycloadducts has been determined by NOE experiments and supported by computational studies at PM3 level. All the obtained compounds have been tested for their in vitro cytotoxic activity and the most potent of them, (3RS,5SR)-2-benzyl-N,N-dimethyl-3-(pyren-1-yl)isoxazolidine-5-carboxamide (7d), showed an IC(50) of 4 μM upon the human lung cancer (A-549) cells. Moreover, compound 7d showed binding constant for the intercalation with calf thymus DNA, poly-d(AT)(2) and poly-d(GC)(2) of 1.7 × 10(5) M(-1), 1.6 × 10(5) M(-1) and 0.3 × 10(5) M(-1), respectively. Biological and docking studies showed that, in vitro, these compounds complex by intercalation between base pairs, approaching the DNA from its minor groove with a preference for the AT nucleobases pairs. Copyright © 2012 Elsevier Masson SAS. All rights reserved.

  19. Isoxazolidinyl polycyclic aromatic hydrocarbons as DNA-intercalating antitumor agents.

    Science.gov (United States)

    Rescifina, Antonio; Chiacchio, Ugo; Corsaro, Antonino; Piperno, Anna; Romeo, Roberto

    2011-01-01

    The second generation and an isosteric series of isoxazolidinyl polycyclic aromatic hydrocarbons, as DNA-intercalator agents designed to act on remotely implanted tumors, have been synthesized in good yields according to the 1,3-dipolar cycloaddition methodology. The structure of the obtained cycloadducts has been determined by NOE experiments and supported by computational studies at PM3 level. The utility of this new template in the synthesis of structures designed to capitalize on its intercalative properties has been examined. All the obtained compounds have been tested for their in vitro cytotoxic activity and the most potent of them showed an IC(50) of 9 μM upon the human lung cancer (A-549) cell and a binding constant, for the intercalation with calf thymus DNA, of 9.6 × 10(4) M(-1). Biological and docking studies showed that these compounds complex exclusively by intercalation between base pairs, approaching the DNA from its minor groove, with a neat selectivity for the AT or GC nucleobases. Copyright © 2010 Elsevier Masson SAS. All rights reserved.

  20. Cationic versus anionic surfactant in tuning the structure and interaction of nanoparticle, protein, and surfactant complexes.

    Science.gov (United States)

    Mehan, Sumit; Aswal, Vinod K; Kohlbrecher, Joachim

    2014-08-26

    The structure and interaction in complexes of anionic Ludox HS40 silica nanoparticle, anionic bovine serum albumin (BSA) protein, and cationic dodecyl trimethylammonium bromide (DTAB) surfactant have been studied using small-angle neutron scattering (SANS). The results are compared with similar complexes having anionic sodium dodecyl sulfate (SDS) surfactant (Mehan, S; Chinchalikar, A. J.; Kumar, S.; Aswal, V. K.; Schweins, R. Langmuir 2013, 29, 11290). In both cases (DTAB and SDS), the structure in nanoparticle-protein-surfactant complexes is predominantly determined by the interactions of the individual two-component systems. The nanoparticle-surfactant (mediated through protein-surfactant complex) and protein-surfactant interactions for DTAB, but nanoparticle-protein (mediated through protein-surfactant complex) and protein-surfactant interactions for SDS, are found to be responsible for the resultant structure of nanoparticle-protein-surfactant complexes. Irrespective of the charge on the surfactant, the cooperative binding of surfactant with protein leads to micellelike clusters of surfactant formed along the unfolded protein chain. The adsorption of these protein-surfactant complexes for DTAB on oppositely charged nanoparticles gives rise to the protein-surfactant complex-mediated aggregation of nanoparticles (similar to that of DTAB surfactant). It is unlike that of depletion-induced aggregation of nanoparticles with nonadsorption of protein-surfactant complexes for SDS in similarly charged nanoparticle systems (similar to that of protein alone). The modifications in nanoparticle aggregation as well as unfolding of protein in these systems as compared to the corresponding two-component systems have also been examined by selectively contrast matching the constituents.

  1. Surfactant-enhanced cellulose nanocrystal Pickering emulsions.

    Science.gov (United States)

    Hu, Zhen; Ballinger, Sarah; Pelton, Robert; Cranston, Emily D

    2015-02-01

    The effect of surfactants on the properties of Pickering emulsions stabilized by cellulose nanocrystals (CNCs) was investigated. Electrophoretic mobility, interfacial tension, confocal microscopy and three-phase contact angle measurements were used to elucidate the interactions between anionic CNCs and cationic alkyl ammonium surfactants didecyldimethylammonium bromide (DMAB) and cetyltrimethylammonium bromide (CTAB). Both surfactants were found to adsorb onto CNCs with concentration-dependent morphology. At low concentrations, individual surfactant molecules adsorbed with alkyl tails pointing outward leading to hydrophobic CNCs. At higher concentrations, above the surfactant's apparent critical micelle concentration, surfactant aggregate morphologies on CNCs were inferred and the hydrophobicity of CNCs decreased. DMAB, which has two alkyl tails, rendered the CNCs more hydrophobic than CTAB which has only a single alkyl tail, at all surfactant concentrations. The change in CNC wettability from surfactant adsorption was directly linked to emulsion properties; adding surfactant increased the emulsion stability, decreased the droplet size, and controlled the internal phase of CNC Pickering emulsions. More specifically, a double transitional phase inversion, from oil-in-water to water-in-oil and back to oil-in-water, was observed for emulsions with CNCs and increasing amounts of DMAB (the more hydrophobic surfactant). With CNCs and CTAB, no phase inversion was induced. This work represents the first report of CNC Pickering emulsions with surfactants as well as the first CNC Pickering emulsions that can be phase inverted. The ability to surface modify CNCs in situ and tailor emulsions by adding surfactants may extend the potential of CNCs to new liquid formulations and extruded/spray-dried materials.

  2. Solubilization of Hydrophobic Dyes in Surfactant Solutions

    Directory of Open Access Journals (Sweden)

    Ali Reza Tehrani-Bagha

    2013-02-01

    Full Text Available In this paper, the use of surfactants for solubilization of hydrophobic organic dyes (mainly solvent and disperse dyes has been reviewed. The effect of parameters such as the chemical structures of the surfactant and the dye, addition of salt and of polyelectrolytes, pH, and temperature on dye solubilization has been discussed. Surfactant self-assemble into micelles in aqueous solution and below the concentration where this occurs—the critical micelle concentration (CMC—there is no solubilization. Above the CMC, the amount of solubilized dye increases linearly with the increase in surfactant concentration. It is demonstrated that different surfactants work best for different dyes. In general, nonionic surfactants have higher solubilization power than anionic and cationic surfactants. It is likely that the reason for the good performance of nonionic surfactants is that they allow dyes to be accommodated not only in the inner, hydrocarbon part of the micelle but also in the headgroup shell. It is demonstrated that the location of a dye in a surfactant micelle can be assessed from the absorption spectrum of the dye-containing micellar solution.

  3. Using biologically soft surfactants for dust suppression

    Energy Technology Data Exchange (ETDEWEB)

    Tkachenko, N.G.; Kolodiichak, V.K.; Motrii, A.E.; Severin, V.D.

    1982-07-01

    This article discusses environmental aspects of using surfactants in coal mines for dust suppression. Surfactants for underground black coal mines in the USSR are divided into three classes: so-called soft surfactants with a decomposition period from 1 to 3 days, hard surfactants with decomposition exceeding a month and an intermediary group. The decomposition process is analyzed; the role played by fermentation is stressed. Environmental effects of surfactant decomposition are evaluated. Selected surfactants tested in Soviet laboratories are described. The results of experimental use of diethanolamide as a surfactant for water injection in coal seams are evaluated. Wetting time amounts to 1 s when a 0.2% concentration is used. When surfactant concentration in water is reduced to 0.05% wetting time does not change; when concentration decreases to 0.025% wetting time increases to 3 s. Surfactant efficiency is investigated under operational conditions in a Donbass mine. Specifications of the working face, mining system and air pollution caused by a shearer loader are discussed. When diethanolamide is used dust suppression efficiency ranges from 86.4 to 90.4%. During the tests diethanolamide concentration in water was 0.05%.

  4. Remediation using trace element humate surfactant

    Energy Technology Data Exchange (ETDEWEB)

    Riddle, Catherine Lynn; Taylor, Steven Cheney; Bruhn, Debra Fox

    2016-08-30

    A method of remediation at a remediation site having one or more undesirable conditions in which one or more soil characteristics, preferably soil pH and/or elemental concentrations, are measured at a remediation site. A trace element humate surfactant composition is prepared comprising a humate solution, element solution and at least one surfactant. The prepared trace element humate surfactant composition is then dispensed onto the remediation site whereby the trace element humate surfactant composition will reduce the amount of undesirable compounds by promoting growth of native species activity. By promoting native species activity, remediation occurs quickly and environmental impact is minimal.

  5. Surfactant nebulisation : lung function, surfactant distribution and pulmonary blood flow distribution in lung lavaged rabbits

    NARCIS (Netherlands)

    Dijk, Peter H.; Heikamp, A; Bambang Oetomo, Sidarto

    1997-01-01

    Objective: Surfactant nebulisation is a promising alternative to surfactant instillation in newborns with the respiratory distress syndrome. Although less surfactant is deposited in the lung, it improves gas exchange, probably due to a superior distribution. We hypothesize that a more uniform distri

  6. Biophysical inhibition of pulmonary surfactant function by polymeric nanoparticles: role of surfactant protein B and C.

    Science.gov (United States)

    Beck-Broichsitter, Moritz; Ruppert, Clemens; Schmehl, Thomas; Günther, Andreas; Seeger, Werner

    2014-11-01

    The current study investigated the mechanisms involved in the process of biophysical inhibition of pulmonary surfactant by polymeric nanoparticles (NP). The minimal surface tension of diverse synthetic surfactants was monitored in the presence of bare and surface-decorated (i.e. poloxamer 407) sub-100 nm poly(lactide) NP. Moreover, the influence of NP on surfactant composition (i.e. surfactant protein (SP) content) was studied. Dose-elevations of SP advanced the biophysical activity of the tested surfactant preparation. Surfactant-associated protein C supplemented phospholipid mixtures (PLM-C) were shown to be more susceptible to biophysical inactivation by bare NP than phospholipid mixture supplemented with surfactant protein B (PLM-B) and PLM-B/C. Surfactant function was hindered owing to a drastic depletion of the SP content upon contact with bare NP. By contrast, surface-modified NP were capable of circumventing unwanted surfactant inhibition. Surfactant constitution influences the extent of biophysical inhibition by polymeric NP. Steric shielding of the NP surface minimizes unwanted NP-surfactant interactions, which represents an option for the development of surfactant-compatible nanomedicines.

  7. Surfactant nebulisation : lung function, surfactant distribution and pulmonary blood flow distribution in lung lavaged rabbits

    NARCIS (Netherlands)

    Dijk, Peter H.; Heikamp, A; Bambang Oetomo, Sidarto

    1997-01-01

    Objective: Surfactant nebulisation is a promising alternative to surfactant instillation in newborns with the respiratory distress syndrome. Although less surfactant is deposited in the lung, it improves gas exchange, probably due to a superior distribution. We hypothesize that a more uniform distri

  8. PERANAN KATALIS TiO2/SiO2-MONTMORILLONIT PADA REAKSI KONVERSI SITRONELAL MENJADI ISOPULEGOL

    Directory of Open Access Journals (Sweden)

    Is Fatimah

    2012-01-01

    Full Text Available Catalytic conversion of citronellal to isopulegol over TiO2/SiO2-montmorillonite catalyst was studied for citronellal isolated from Cymbopogon leaf oil. The role of physico-chemical characteristics of montmorillonite and SiO2-montmorillonit catalyst on total conversion, activity and selectivity to produce isopulegol was studied. Activity test was conducted for citronellal cyclication for 4 hour. The total conversion, catalyst activity and catalyst selectivity to produce isopulegol were evaluated based on product composition obtained by GC-MS analysis. The experimental result showed that TiO2/SiO2-montmorillonite plays role in the increase of total conversion significantly from 87.80% over SiO2-montmorillonit and 85.38% over natural montmorillonite become 95.53%. Total conversion and selectivity of the catalyst to produce isopulegol increase could be related to Lewis acidity of TiO2/SiO2-montmorillonite, and also specific surface area enhancement. However, in the range of 1:1.25 to 1:5.0 catalyst to citronellal mass ratio, there was no influence on total conversion and selectivity to produce isopulegol. This may be caused by dominant influence of Lewis acidity compared to other physico-chemical characteristic of material. Kinetics study of the reaction showed that TiO2 dispersion on SiO2-montmorillonite almost doubles the reaction rate constant with the factor of 1.955. Konversi katalitik sitronelal menjadi isopulegol menggunakan katalis TiO2/SiO2-montmorillonit dipelajari terhadap sitronelal hasil isolasi minyak daun sereh. Peranan karakter fisikokimiawi material katalis montmorillonit alam dan SiO2-montmorillonit terhadap konversi total, aktivitas dan selektivitas dalam pembentukan isopulegol dipelajari. Uji aktivitas katalis dilakukan pada reaksi siklisasi sitronelal selama 4 jam. Konversi total, aktivitas katalis dan selektivitas terhadap isopulegol dihitung berdasar perubahan komposisi hasil reaksi yang ditentukan menggunakan GC-MS. Hasil

  9. A green and efficient deoximation using H2O2 catalyzed by montmorillonite-K10 supported COCl2

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    Oximes were oxidized to the corresponding carbonyl compounds in good to high yields by environmentally friendly and green oxidant, H2O2 catalyzed by montmorillonite K310 supported cobalt(Ⅱ) chloride.

  10. Low frequency dielectric relaxation processes and ionic conductivity of montmorillonite clay nanoparticles colloidal suspension in poly(vinyl pyrrolidone−ethylene glycol blends

    Directory of Open Access Journals (Sweden)

    2008-11-01

    Full Text Available The dielectric dispersion behaviour of montmorillonite (MMT clay nanoparticles colloidal suspension in poly(vinyl pyrrolidone-ethylene glycol (PVP-EG blends were investigated over the frequency range 20 Hz to 1 MHz at 30°C. The 0, 1, 2, 3, 5 and 10 wt% MMT clay concentration of the weight of total solute (MMT+PVP were prepared in PVP-EG blends using EG as solvent. The complex relative dielectric function, alternating current (ac electrical conductivity, electric modulus and impedance spectra of these materials show the relaxation processes corresponding to the micro-Brownian motion of PVP chain, ion conduction and electrode polarization phenomena. The real part of ac conductivity spectra of these materials obeys Jonscher power law σ′(ω =σdc + Aωn in upper frequency end of the measurement, whereas dispersion in lower frequency end confirms the presence of electrode polarization effect. It was observed that the increase of clay concentration in the PVP-EG blends significantly increases the ac conductivity values, and simultaneously reduces the ionic conductivity relaxation time and electric double layer relaxation time, which suggests that PVP segmental dynamics and ionic motion are strongly coupled. The intercalation of EG structures in clay galleries and exfoliation of clay sheets by adsorption of PVP-EG structures on clay surfaces are discussed by considering the hydrogen bonding interactions between the hydroxyl group (–OH of EG molecules, carbonyl group (C=O of PVP monomer units, and the hydroxylated aluminate surfaces of the MMT clay particles. Results suggest that the colloidal suspension of MMT clay nano particles in the PVP-EG blends provide a convenient way to obtain an electrolyte solution with tailored electrical conduction properties.

  11. Ge-intercalated graphene: The origin of the p-type to n-type transition

    KAUST Repository

    Kaloni, Thaneshwor P.

    2012-09-01

    Recently huge interest has been focussed on Ge-intercalated graphene. In order to address the effect of Ge on the electronic structure, we study Ge-intercalated free-standing C 6 and C 8 bilayer graphene, bulk C 6Ge and C 8Ge, as well as Ge-intercalated graphene on a SiC(0001) substrate, by density functional theory. In the presence of SiC(0001), there are three ways to obtain n-type graphene: i) intercalation between C layers; ii) intercalation at the interface to the substrate in combination with Ge deposition on the surface; and iii) cluster intercalation. All other configurations under study result in p-type states irrespective of the Ge coverage. We explain the origin of the different doping states and establish the conditions under which a transition occurs. © Copyright EPLA, 2012.

  12. Hemolysis by surfactants--A review.

    Science.gov (United States)

    Manaargadoo-Catin, Magalie; Ali-Cherif, Anaïs; Pougnas, Jean-Luc; Perrin, Catherine

    2016-02-01

    An overview of the use of surfactants for erythrocyte lysis and their cell membrane action mechanisms is given. Erythrocyte membrane characteristics and its association with the cell cytoskeleton are presented in order to complete understanding of the erythrocyte membrane distortion. Cell homeostasis disturbances caused by surfactants might induce changes starting from shape modification to cell lysis. Two main mechanisms are hypothesized in literature which are osmotic lysis and lysis by solubilization even if the boundary between them is not clearly defined. Another specific mechanism based on the formation of membrane pores is suggested in the particular case of saponins. The lytic potency of a surfactant is related to its affinity for the membrane and the modification of the lipid membrane curvature. This is to be related to the surfactant shape defined by its hydrophobic and hydrophilic moieties but also by experimental conditions. As a consequence, prediction of the hemolytic potency of a given surfactant is challenging. Several studies are focused on the relation between surfactant erythrolytic potency and their physico-chemical parameters such as the critical micellar concentration (CMC), the hydrophile-lipophile balance (HLB), the surfactant membrane/water partition coefficient (K) or the packing parameter (P). The CMC is one of the most important factors considered even if a lytic activity cut-off effect points out that the only consideration of CMC not enough predictive. The relation K.CMC must be considered in addition to the CMC to predict the surfactant lytic capacity within the same family of non ionic surfactant. Those surfactant structure/lytic activity studies demonstrate the requirement to take into account a combination of physico-chemical parameters to understand and foresee surfactant lytic potency.

  13. Montmorillonite K-10 as a catalyst in the synthesis of 5, 5-disubstituted hydantoins under ultrasound irradiation

    Indian Academy of Sciences (India)

    J Safari; L Javadian

    2013-09-01

    The rapid and highly efficient synthesis of 5,5-disubstituted hydantoins achieved by threecomponent condensation of corresponding ketones and aldehydes, potassium cyanide and ammonium carbonate in an additional reaction under ultrasound irradiation by using montmorillonite K-10 as a heterogenous catalyst. Utilizing ultrasound irradiation and montmorillonite in this method has several benefits, for example short reaction time, high yield and use of recyclable catalyst.

  14. Thermoelectric Properties of Li-Intercalated ZrSe2 Single Crystals

    DEFF Research Database (Denmark)

    Holgate, Tim; Liu, Yufei; Hitchcock, Dale

    2013-01-01

    Zirconium diselenide (ZrSe2) is one of many members of the layer-structured transition-metal dichalcogenide family. The structure of these materials features a weakly bonded van der Waals gap between covalently bonded CdI2-type atomic layers that may host a wide range of intercalants. Intercalation......, and low cost of such materials, merit further thermoelectric investigations of intercalated zirconium diselenide, especially in conjunction with a substitutional doping approach....

  15. Intercalation of psoralen into DNA of plastid chromosomes decreases late during barley chloroplast development.

    OpenAIRE

    Davies, J. P.; Thompson, R.J.; Mosig, G

    1991-01-01

    We have used a DNA crosslinking assay to measure intercalation of the psoralen derivative HMT (4'-hydroxymethyl-4,5',8-trimethylpsoralen) into barley (Hordeum vulgare) plastid chromosomal DNA during chloroplast and etioplast development. Intercalation into DNA in intact plastids in vivo and in plastid lysates in vitro shows that chromosomal DNA in the most mature chloroplasts intercalates HMT less efficiently than DNA in younger chloroplasts. In contrast, there is no change in HMT intercalati...

  16. Synthesis of ACECLOFENAC/HYDROXYPROPYL-β-CYCLODEXTRIN Intercalated Layered Double Hydroxides and Controlled Release Properties

    Science.gov (United States)

    Li, Shifeng; Shen, Yanming; Liu, Dongbin; Fan, Lihui; Wu, Keke; Xiao, Min

    2013-04-01

    Aceclofenac (AC)/hydroxypropyl-β-cyclodextrin (HP-β-CD) complex intercalated layered double hydroxides (LDHs) have been synthesized by reconstruction method. X-ray diffraction, Fourier transform infrared and thermal gravimetric analyses indicated a successful intercalation of AC/HP-β-CD complex into the LDHs gallery. The AC release properties were also studied in different pH values buffer solution. The results indicate that the AC/HP-β-CD intercalated LDH has a potential application in drug delivery agent.

  17. Water-conducting Characteristics and Micro-dynamic Self-adjusting Behavior of Polyacrylamide/Montmorillonite Coating

    Institute of Scientific and Technical Information of China (English)

    DU Hongmei; ZHANG Zengzhi; WU Miaomiao; ZHAO Jin

    2015-01-01

    A water-conducting polyacrylamide/montmorillonite coating was prepared by solution-blending. The coating was coated on fiber and then composited with polymer to form a composite film material that used for water saving and tree planting in arid and desert regions. The coating’s water-conducting characteristics and dynamic self-adjusting behavior were investigated by Fourier transform infrared (FTIR) spectroscopy, thermal analysis (TG-DTA), and environmental scanning electron microscopy (ESEM).The results showed that the coating’s water-conducting rate increased but water-retention capacity weakened with increasing montmorillonite content. The water-loss rate was positively related to temperature and negatively related to soil moisture. Water potential greatly influenced the water-conducting rate of the coating during its water conduction process. When the coating was at a low water potential, the montmorillonite particles interconnected and water was conducted quickly via montmorillonite layers, whereas when the coating was at a high potential, the montmorillonite particles disconnected and water was conducted slowly via the swelled polyacrylamide net structure. The rate can be regulated by changing the proportion of polyacrylamide and montmorillonite to guarantee a reasonable water supply for trees and make trees easier to survive. Thus, the survival rate of trees can be increased and the use of water resources can be signiifcantly reduced.

  18. Structured fluids polymers, colloids, surfactants

    CERN Document Server

    Witten, Thomas A

    2010-01-01

    Over the last thirty years, the study of liquids containing polymers, surfactants, or colloidal particles has developed from a loose assembly of facts into a coherent discipline with substantial predictive power. These liquids expand our conception of what condensed matter can do. Such structured-fluid phenomena dominate the physical environment within living cells. This book teaches how to think of these fluids from a unified point of view showing the far-reaching effects ofthermal fluctuations in producing forces and motions. Keeping mathematics to a minimum, the book seeks the simplest expl

  19. Innovation in surfactant therapy I: surfactant lavage and surfactant administration by fluid bolus using minimally invasive techniques.

    Science.gov (United States)

    Dargaville, Peter A

    2012-01-01

    Innovation in the field of exogenous surfactant therapy continues more than two decades after the drug became commercially available. One such innovation, lung lavage using dilute surfactant, has been investigated in both laboratory and clinical settings as a treatment for meconium aspiration syndrome (MAS). Studies in animal models of MAS have affirmed that dilute surfactant lavage can remove meconium from the lung, with resultant improvement in lung function. In human infants both non-randomised studies and two randomised controlled trials have demonstrated a potential benefit of dilute surfactant lavage over standard care. The largest clinical trial, performed by our research group in infants with severe MAS, found that lung lavage using two 15-ml/kg aliquots of dilute surfactant did not reduce the duration of respiratory support, but did appear to reduce the composite outcome of death or need for extracorporeal membrane oxygenation. A further trial of lavage therapy is planned to more precisely define the effect on survival. Innovative approaches to surfactant therapy have also extended to the preterm infant, for whom the more widespread use of continuous positive airway pressure (CPAP) has meant delaying or avoiding administration of surfactant. In an effort to circumvent this problem, less invasive techniques of bolus surfactant therapy have been trialled, including instillation directly into the pharynx, via laryngeal mask and via brief tracheal catheterisation. In a recent clinical trial, instillation of surfactant into the trachea using a flexible feeding tube was found to reduce the need for subsequent intubation. We have developed an alternative method of brief tracheal catheterisation in which surfactant is delivered via a semi-rigid vascular catheter inserted through the vocal cords under direct vision. In studies to date, this technique has been relatively easy to perform, and resulted in rapid improvement in lung function and reduced need for

  20. Tuning the Properties of Polymer Bulk Heterojunction Solar Cells by Adjusting Fullerene Size to Control Intercalation

    KAUST Repository

    Cates, Nichole C.

    2009-12-09

    We demonstrate that intercalation of fullerene derivatives between the side chains of conjugated polymers can be controlled by adjusting the fullerene size and compare the properties of intercalated and nonintercalated poly(2,5-bis(3-hexadecylthiophen-2-yl)thieno[3,2-b]thiophene (pBTTT):fullerene blends. The intercalated blends, which exhibit optimal solar-cell performance at 1:4 polymer:fullerene by weight, have better photoluminescence quenching and lower absorption than the nonintercalated blends, which optimize at 1:1. Understanding how intercalation affects performance will enable more effective design of polymer:fullerene solar cells. © 2009 American Chemical Society.

  1. Structure and thermal decomposition of sulfated β-cyclodextrin intercalated in a layered double hydroxide

    Science.gov (United States)

    Wang, Ji; Wei, Min; Rao, Guoying; Evans, David G.; Duan, Xue

    2004-01-01

    The sodium salt of hexasulfated β-cyclodextrin has been synthesized and intercalated into a magnesium-aluminum layered double hydroxide by ion exchange. The structure, composition and thermal decomposition behavior of the intercalated material have been studied by variable temperature X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), inductively coupled plasma emission spectroscopy (ICP), and thermal analysis (TG-DTA) and a model for the structure has been proposed. The thermal stability of the intercalated sulfated β-cyclodextrin is significantly enhanced compared with the pure form before intercalation.

  2. Structure and physical properties of gallium selenide laser-intercalated with nickel

    Science.gov (United States)

    Pokladok, N. T.; Grygorchak, I. I.; Lukiyanets, B. A.; Popovich, D. I.

    2007-04-01

    Intercalated crystals of indium and gallium selenide are prepared. It is shown that laser intercalation of nickel into GaSe samples leads to a giant magnetoresistive effect whose magnitude and sign depend on the concentration of the guest component. The giant magnetoresistive effect in the InSe intercalation compounds is considerably weaker and does not exceed 5%. The experimental data obtained are explained in terms of magnetic delocalization (localization) of charge carriers with the participation of states of intercalated magnetically active atoms in the vicinity of the Fermi level.

  3. Mechanism of Si intercalation in defective graphene on SiC

    KAUST Repository

    Kaloni, Thaneshwor P.

    2012-10-01

    Previously reported experimental findings on Si-intercalated graphene on SiC(0001) seem to indicate the possibility of an intercalation process based on the migration of the intercalant through atomic defects in the graphene sheet. We employ density functional theory to show that such a process is in fact feasible and obtain insight into its details. By means of total energy and nudged elastic band calculations we are able to establish the mechanism on an atomic level and to determine the driving forces involved in the different steps of the intercalation process through atomic defects.

  4. Surfactant Adsorption: A Revised Physical Chemistry Lab

    Science.gov (United States)

    Bresler, Marc R.; Hagen, John P.

    2008-01-01

    Many physical chemistry lab courses include an experiment in which students measure surface tension as a function of surfactant concentration. In the traditional experiment, the data are fit to the Gibbs isotherm to determine the molar area for the surfactant, and the critical micelle concentration is used to calculate the Gibbs energy of micelle…

  5. Surfactant effects on soil aggregate tensile strength

    Science.gov (United States)

    Little is known regarding a soil aggregate's tensile strength response to surfactants that may be applied to alleviate soil water repellency. Two laboratory investigations were performed to determine surfactant effects on the tensile strength of 1) Ap horizons of nine wettable, agricultural soils co...

  6. Investigations on uranium sorption on bentonite and montmorillonite, respectively, and uranium in environmental samples; Untersuchungen zur Uransorption an Bentonit bzw. Montmorillonit sowie von Uran in Umweltproben

    Energy Technology Data Exchange (ETDEWEB)

    Azeroual, Mohamed

    2010-09-22

    The geotechnical barrier is an important component of a geological repository and consists of compacted bentonite surrounding radioactive waste containers. Its most important functions are, to retard the radionuclide migration into the biosphere and to prevent groundwater contact with containers. lt is therefore of central importance to investigate the bentonite material on its capacity to sorb radionuclides under near-natural chemical and physical conditions. The purpose of this work was to study the adsorption of uranium(VI) on bentonit and on montmorillonite-standards at high uranium concentrations. Thereby, a special account was given to the calcium-uranyl-carbonate complexation, which leads to the formation of very stable and mobile uncharged Ca{sub 2}UO{sub 2}(CO{sub 3}){sub 3} complex. Results of batch experiments showed that the dicalcium-uranyl-tricarbonate complexation lowers the uranium(VI) sorption on natural clay (bentonite) by a factor of up to 3. After 21 days of contact time, about 40 % and 20 % of the initial uranium(VI)concentration were sorbed on Na-bentonite and ea-bentonite, respectively, from a solution with Ca{sub 2}UO{sub 2}(CO{sub 3}){sub 3} dominating the uranium(VI) speciation. On the contrary, about 55 % of the initial uranium(VI)-concentration were sorbed on thes clays from the solution, in which (UO{sub 2}){sub 2}CO{sub 3}(OH){sub 3}{sup -} complex dominated the uranium(VI) speciation. Thus uranium(VI) sorption is more strongly influenced by the solution composition than by bentonite type. Na-bentonite should be used instead of ea-bentonite as a geotechnical barrier, since calcium-uranyl-carbonate complexation may be a realistic scenario. Further SEM-EDX and HREM-EDX studies showed that uranium(VI) sorption occurred predominantly on montmorillonite, which is the main component of bentonite. Uranium(VI) sorption on bentonite's accessory Minerals (pyrite, calcite, mica, and feldspar) was not observed. Investigation of uranium

  7. Investigations on uranium sorption on bentonite and montmorillonite, respectively, and uranium in environmental samples; Untersuchungen zur Uransorption an Bentonit bzw. Montmorillonit sowie von Uran in Umweltproben

    Energy Technology Data Exchange (ETDEWEB)

    Azeroual, Mohamed

    2010-09-22

    The geotechnical barrier is an important component of a geological repository and consists of compacted bentonite surrounding radioactive waste containers. Its most important functions are, to retard the radionuclide migration into the biosphere and to prevent groundwater contact with containers. lt is therefore of central importance to investigate the bentonite material on its capacity to sorb radionuclides under near-natural chemical and physical conditions. The purpose of this work was to study the adsorption of uranium(VI) on bentonit and on montmorillonite-standards at high uranium concentrations. Thereby, a special account was given to the calcium-uranyl-carbonate complexation, which leads to the formation of very stable and mobile uncharged Ca{sub 2}UO{sub 2}(CO{sub 3}){sub 3} complex. Results of batch experiments showed that the dicalcium-uranyl-tricarbonate complexation lowers the uranium(VI) sorption on natural clay (bentonite) by a factor of up to 3. After 21 days of contact time, about 40 % and 20 % of the initial uranium(VI)concentration were sorbed on Na-bentonite and ea-bentonite, respectively, from a solution with Ca{sub 2}UO{sub 2}(CO{sub 3}){sub 3} dominating the uranium(VI) speciation. On the contrary, about 55 % of the initial uranium(VI)-concentration were sorbed on thes clays from the solution, in which (UO{sub 2}){sub 2}CO{sub 3}(OH){sub 3}{sup -} complex dominated the uranium(VI) speciation. Thus uranium(VI) sorption is more strongly influenced by the solution composition than by bentonite type. Na-bentonite should be used instead of ea-bentonite as a geotechnical barrier, since calcium-uranyl-carbonate complexation may be a realistic scenario. Further SEM-EDX and HREM-EDX studies showed that uranium(VI) sorption occurred predominantly on montmorillonite, which is the main component of bentonite. Uranium(VI) sorption on bentonite's accessory Minerals (pyrite, calcite, mica, and feldspar) was not observed. Investigation of uranium

  8. Metathesis depolymerization for removable surfactant templates.

    Energy Technology Data Exchange (ETDEWEB)

    Zifer, Thomas (Sandia National Laboratories, Livermore, CA); Wheeler, David Roger; Rahimian, Kamayar; McElhanon, James Ross (Sandia National Laboratories, Livermore, CA); Long, Timothy Michael; Jamison, Gregory Marks; Loy, Douglas Anson (Los Alamos National Laboratories, Los Alamos, NM); Kline, Steven R. (National Institute of Standards and Technology, Gaithersburg, MD); Simmons, Blake Alexander (Sandia National Laboratories, Livermore, CA)

    2005-03-01

    Current methodologies for the production of meso- and nanoporous materials include the use of a surfactant to produce a self-assembled template around which the material is formed. However, post-production surfactant removal often requires centrifugation, calcination, and/or solvent washing which can damage the initially formed material architecture(s). Surfactants that can be disassembled into easily removable fragments following material preparation would minimize processing damage to the material structure, facilitating formation of templated hybrid architectures. Herein, we describe the design and synthesis of novel cationic and anionic surfactants with regularly spaced unsaturation in their hydrophobic hydrocarbon tails and the first application of ring closing metathesis depolymerization to surfactant degradation resulting in the mild, facile decomposition of these new compounds to produce relatively volatile nonsurface active remnants.

  9. Enhanced Oil Recovery with Surfactant Flooding

    DEFF Research Database (Denmark)

    Sandersen, Sara Bülow

    Enhanced oil recovery (EOR) is being increasingly applied in the oil industry and several different technologies have emerged during, the last decades in order to optimize oil recovery after conventional recovery methods have been applied. Surfactant flooding is an EOR technique in which the phase...... both for complex surfactant systems as well as for oil and brine systems. It is widely accepted that an increase in oil recovery can be obtained through flooding, whether it is simple waterflooding, waterflooding where the salinity has been modified by the addition or removal of specific ions (socalled...... “smart” waterflooding) or surfactant flooding. High pressure experiments have been carried out in this work on a surfactant system (surfactant/ oil/ brine) and on oil/ seawater systems (oil/ brine). The high pressure experiments were carried out on a DBR JEFRI PVT cell, where a glass window allows...

  10. Fibrinogen stability under surfactant interaction.

    Science.gov (United States)

    Hassan, Natalia; Barbosa, Leandro R S; Itri, Rosangela; Ruso, Juan M

    2011-10-01

    Differential scanning calorimetry (DSC), circular dichroism (CD), difference spectroscopy (UV-vis), Raman spectroscopy, and small-angle X-ray scattering (SAXS) measurements have been performed in the present work to provide a quantitatively comprehensive physicochemical description of the complexation between bovine fibrinogen and the sodium perfluorooctanoate, sodium octanoate, and sodium dodecanoate in glycine buffer (pH 8.5). It has been found that sodium octanoate and dodecanoate act as fibrinogen destabilizer. Meanwhile, sodium perfluorooctanoate acts as a structure stabilizer at low molar concentration and as a destabilizer at high molar concentration. Fibrinogen's secondary structure is affected by all three studied surfactants (decrease in α-helix and an increase in β-sheet content) to a different extent. DSC and UV-vis revealed the existence of intermediate states in the thermal unfolding process of fibrinogen. In addition, SAXS data analysis showed that pure fibrinogen adopts a paired-dimer structure in solution. Such a structure is unaltered by sodium octanoate and perfluoroctanoate. However, interaction of sodium dodecanoate with the fibrinogen affects the protein conformation leading to a complex formation. Taken together, all results evidence that both surfactant hydrophobicity and tail length mediate the fibrinogen stability upon interaction. Copyright © 2011 Elsevier Inc. All rights reserved.

  11. Study of swelling-shrinkage regularity of montmorillonite crystal and its relation with matric suction

    Institute of Scientific and Technical Information of China (English)

    谭罗荣; 孔令伟

    2001-01-01

    The swell-shrinking mineral of saturated and unsaturated expansive soil has important effect on engineering mechanical behavior. Based on the swelling-shrinkage change regularity of montmorillonite crystal in this paper, the actions between various interlayers of montmorillonite crystal are generally summarized as two kinds of action potentials-shrinkage potential and swelling potential. Moreover, through the experimental research and analysis, the expression formula for variations of the swelling potential and shrinkage potential with interlayer distance is presented, and the regularity of matric suction variations with interlayer distance is also obtained for unsaturated expansive soil. It may provide a new theoretical basis and research path for further research on the swelling-shrinkage mechanism of expansive soil and matric suction potential of unsaturated soil.

  12. Ag-Coated Heterostructures of ZnO-TiO2/Delaminated Montmorillonite as Solar Photocatalysts

    Science.gov (United States)

    Hinojosa, Mariana; Tobajas, Montserrat; Alvarez, Maria Ariadna; Rodríguez-González, Vicente; Rodriguez, Juan Jose

    2017-01-01

    Heterostructures based on ZnO-TiO2/delaminated montmorillonite coated with Ag have been prepared by sol–gel and photoreduction procedures, varying the Ag and ZnO contents. They have been thoroughly characterized by XRD, WDXRF, UV–Vis, and XPS spectroscopies, and N2 adsorption, SEM, and TEM. In all cases, the montmorillonite was effectively delaminated with the formation of TiO2 anatase particles anchored on the clay layer’s surface, yielding porous materials with high surface areas. The structural and textural properties of the heterostructures synthesized were unaffected by the ZnO incorporated. The photoreduction led to solids with Ag nanoparticles decorating the surface. These materials were tested as photocatalysts for the degradation of several emerging contaminants with different nitrogen-bearing chemical structures under solar light. The catalysts yielded high rates of disappearance of the starting pollutants and showed quite stable performance upon successive applications. PMID:28817106

  13. Radiolysis of aqueous solutions of acetic acid in the presence of Na-montmorillonite

    Science.gov (United States)

    Navarro-Gonzalez, R.; Negron-Mendoza, A.; Ramos, S.; Ponnamperuma, C.

    1990-01-01

    The gamma-irradiation of 0.8 mol dm-3 aqueous, oxygen-free acetic acid solutions was investigated in the presence or absence of Na-montmorillonite. H2, CH4, CO, CO2, and several polycarboxylic acids were formed in all systems. The primary characteristics observed in the latter system were: (1) Higher yield of the decomposition of acetic acid; (2) Lower yield of the formation of polycarboxylic acids; (3) No effect on the formation of methane; (4) Higher yield of the formation of carbon dioxide; and (5) The reduction of Fe3+ in the octahedral sites of Na-montmorillonite. A possible reaction scheme was proposed to account for the observed changes. The results are important in understanding heterogeneous processes in radiation catalysis and might be significant to prebiotic chemistry.

  14. Synthesis of a red iron oxide/montmorillonite pigment in a CO2-rich brine solution.

    Science.gov (United States)

    Montes-Hernandez, G; Pironon, J; Villieras, F

    2006-11-15

    The homoionic calcium-montmorillonite was used to synthesize a red iron oxide/clay pigment in a CO2-rich brine solution (0.5 M of NaCl) by using an agitated batch-reactor (engineer autoclave). The operating conditions were 15 days of reaction, 200 bars of pressure and 150 degrees C of temperature. SEM/EDS, STEM/EDS, XRD and Infrared Spectrometry were performed to characterize before and after reaction the solid phase. The results showed the precipitation of spherical nanoparticles (50-500 nm) of iron oxide (Fe2O3) dispersed and/or coagulated in the clay-matrix. Evidently, this oxide produced red coloration in the final product. For this case, the Fe3+ cation was provided to the aqueous solution by the dissolution of Ca-montmorillonite, particularly, the dissolution of most fine particles contained in the starting clay material. The cation exchange process and precipitation of polymorph silica were also observed.

  15. Ag-Coated Heterostructures of ZnO-TiO2/Delaminated Montmorillonite as Solar Photocatalysts

    Directory of Open Access Journals (Sweden)

    Carolina Belver

    2017-08-01

    Full Text Available Heterostructures based on ZnO-TiO2/delaminated montmorillonite coated with Ag have been prepared by sol–gel and photoreduction procedures, varying the Ag and ZnO contents. They have been thoroughly characterized by XRD, WDXRF, UV–Vis, and XPS spectroscopies, and N2 adsorption, SEM, and TEM. In all cases, the montmorillonite was effectively delaminated with the formation of TiO2 anatase particles anchored on the clay layer’s surface, yielding porous materials with high surface areas. The structural and textural properties of the heterostructures synthesized were unaffected by the ZnO incorporated. The photoreduction led to solids with Ag nanoparticles decorating the surface. These materials were tested as photocatalysts for the degradation of several emerging contaminants with different nitrogen-bearing chemical structures under solar light. The catalysts yielded high rates of disappearance of the starting pollutants and showed quite stable performance upon successive applications.

  16. Microwave-Assisted Preparation of Biodegradable Water Absorbent Polyacrylonitrile/Montmorillonite Clay Nanocomposite

    Directory of Open Access Journals (Sweden)

    Prafulla K. Sahoo

    2011-01-01

    Full Text Available Polyacrylonitrile (PAN/Montmorillonite (MMT clay nanocomposite was prepared in a microwave oven using a transition metal Co(III complex taking ammonium persulfate (APS as initiator with a motive of converting hydrophobic PAN into hydrophilic nanocomposite material via nanotechnology by the inclusion of MMT to the virgin polymer. UV-visible spectral analysis revealed various interactions between the developed complex with other reaction components. The formation of the PAN/MMT nanocomposites was characterized by FTIR. Furthermore, as evidenced by X-ray diffraction (XRD, transmission electron microscopy (TEM, the composite so obtained was found to have nano-order. XRD and TEM were suggesting that montmorillonite layers were exfoliated during the polymerization process. An increasing in the thermal stability for the developed nanocomposite was recorded by thermogravimetric analysis (TGA. The water absorption and biodegradation properties were carried out for its ecofriendly nature and better commercialization.

  17. Improvement in tensile properties of PVC–montmorillonite nanocomposites through controlled uniaxial stretching

    Indian Academy of Sciences (India)

    Adnan Sarfraz; Muhammad Farooq Warsi; Muhammad Ilyas Sarwar; Muhammad Ishaq

    2012-08-01

    In this paper we present the results exhibiting an improvement in the tensile properties of polyvinyl chloride (PVC)–montmorillonite nanocomposites through uniaxial stretching. The clay was dispersed in PVC matrix with the help of dodecylamine. PVC–montmorillonite nanocomposites films containing varying amounts of clay (0–5%) were produced through solution elution technique. The films were stretched uniaxially at a constant temperature of 80 °C in three different steps using controlled loads. X-ray diffraction and stress–strain curves were obtained for both unstretched and stretched films in order to determine the improvement in various properties. The controlled uniaxial stretching of films close to the softening temperature of PVC has resulted in enhancement in the degree of crystallinity in the nanocomposites. This improvement in the structural order has also imparted increase in tensile strength and Young’s modulus of the nanocomposite films.

  18. Cellular Uptake Behavior of Fluorescein: Intercalated Layered Double Hydroxide

    Science.gov (United States)

    Tanaka, Miyuki; Aisawa, Sumio; Hirahara, Hidetoshi; Narita, Eiichi; Yin, Shu; Sato, Tsugio

    2012-06-01

    In order to define the ability of layered double hydroxide (LDH) as materials for drug delivery, fluorescein (Fluo) anion intercalated LDH (Fluo/LDH) was synthesized by hydrothermal treatment and observed the cellular uptake of the Fluo/LDH for mammalian cell (L929). The synthesized Fluo/LDH showed a LDH structure, high fluorescence and low cytotoxicity. According to the fluorescence, confocal and TEM images of cells, the Fluo/LDH seemed to be internalized into the L929 cell by cellular endocytosis and dissolved inside the cell to exhibit the fluorescence of cellular cytoplasm.

  19. Properties of atomic intercalated boron nitride K4 type crystals

    OpenAIRE

    Itoh, Masahiro; Takami, Seiichi; Kawazoe, Yoshiyuki; Adschiri, Tadafumi

    2010-01-01

    The stability of atomic intercalated boron nitride K4 crystal structures, XBN (X=H, Li, Be, B, C, N, O, F, Na, Mg, Al, Si, P, S, Cl, K, Ca, Ga, Ge, As, Se, Br, Rb or Sr) is evaluated by the geometric optimization and frozen phonon calculations based on the first principles calculations. NaBN, MgBN, GaBN, FBN and ClBN are found to be stable. NaBN, GaBN, FBN and ClBN are metallic, whereas MgBN is semiconducting.

  20. Properties of atomic intercalated carbon K4 crystals

    OpenAIRE

    Itoh, Masahiro; Takami, Seiichi; Kawazoe, Yoshiyuki; Adschiri, Tadafumi

    2009-01-01

    The stability of atomic intercalated carbon $K_{4}$ crystals, XC$_{2}$ (X=H, Li, Be, B, C, N, O, F, Na, Mg, Al, Si, P, S, Cl, K, Ca, Ga, Ge, As, Se, Br, Rb or Sr) is evaluated by geometry optimization and frozen phonon analysis based on first principles calculations. Although C $K_{4}$ is unstable, NaC$_{2}$ and MgC$_{2}$ are found to be stable. It is shown that NaC$_{2}$ and MgC$_{2}$ are metallic and semi conducting, respectively.