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Sample records for zeolite modification copper

  1. Copper-containing zeolite catalysts

    DOEpatents

    Price, G.L.; Kanazirev, V.

    1996-12-10

    A catalyst useful in the conversion of nitrogen oxides or in the synthesis of nitriles or imines from amines, is formed by preparing an intimate mechanical mixture of a copper (II)-containing species, such as CuO or CuCl{sub 2}, or elemental copper, with a zeolite having a pore mouth comprising 10 oxygen atoms, such as ZSM-5, converting the elemental copper or copper (II) to copper (I), and driving the copper (I) into the zeolite.

  2. Copper-containing zeolite catalysts

    DOEpatents

    Price, Geoffrey L. (Baton Rouge, LA); Kanazirev, Vladislav (Sofia, BG)

    1996-01-01

    A catalyst useful in the conversion of nitrogen oxides or in the synthesis of nitriles or imines from amines, formed by preparing an intimate mechanical mixture of a copper (II)-containing species, such as CuO or CuCl.sub.2, or elemental copper, with a zeolite having a pore mouth comprising 10 oxygen atoms, such as ZSM-5, converting the elemental copper or copper (II) to copper (I), and driving the copper (I) into the zeolite.

  3. Chiral modification of copper exchanged zeolite-Y with cinchonidine and its application in the asymmetric Henry reaction.

    PubMed

    Deka, Jogesh; Satyanarayana, L; Karunakar, G V; Bhattacharyya, Pradip Kr; Bania, Kusum K

    2015-12-28

    Chirally modified Cu(2+) exchanged zeolite-Y was synthesized by direct adsorption of cinchonidine under ambient conditions. The chirally modified materials were characterized using various spectrochemical and physicochemical techniques viz. BET, FTIR, MAS ((1)H and (13)C NMR), XPS, SEM, cyclic voltammetry and PXRD. Characteristic peaks of cinchonidine observed in the supported materials confirmed the adsorption of cinchonidine and its coordination with the Cu(2+) active site on copper exchanged zeolite-Y. (13)C SSNMR and XPS analysis however confirmed for the half encapsulation process, only the quinoline ring of cinchonidine gets coordinated to the internal metal sites via the N atom while the quinuclidine moiety extends out of the host surface. Cinchonidine supported Cu(2+)-Y zeolites were found to exhibit good catalytic performance in the asymmetric Henry reaction. (1)H SSNMR studies also confirmed the protonation of the N atom of the quinuclidine ring during the course of the Henry reaction. Heterogeneous chiral catalysts were effective for up to two consecutive cycles. Leaching of cinchonidine after the second cycle was found to have a negative result in the catalytic performance. PMID:26579982

  4. Copper-Exchanged Zeolite L Traps Oxygen

    NASA Technical Reports Server (NTRS)

    Sharma, Pramod K.; Seshan, Panchalam K.

    1991-01-01

    Brief series of simple chemical treatments found to enhance ability of zeolite to remove oxygen from mixture of gases. Thermally stable up to 700 degrees C and has high specific surface area which provides high capacity for adsorption of gases. To increase ability to adsorb oxygen selectively, copper added by ion exchange, and copper-exchanged zeolite reduced with hydrogen. As result, copper dispersed atomically on inner surfaces of zeolite, making it highly reactive to oxygen, even at room temperature. Reactivity to oxygen even greater at higher temperatures.

  5. Modification of Phenolic Oximes for Copper Extraction 

    E-print Network

    Forgan, Ross Stewart

    2008-01-01

    The thesis deals with the modification of salicylaldoxime-based reagents used in hydrometallurgical extraction, addressing rational ligand design to tune copper(II) extractant strengths and also the development of reagents ...

  6. Zeolites

    NASA Technical Reports Server (NTRS)

    1992-01-01

    Zeolites are crystalline aluminosilicates that have complex framework structures. However, there are several features of zeolite crystals that make unequivocal structure determinations difficult. The acquisition of reliable structural information on zeolites is greatly facilitated by the availability of high-quality specimens. For structure determinations by conventional diffraction techniques, large single-crystal specimens are essential. Alternatively, structural determinations by powder profile refinement methods relax the constraints on crystal size, but still require materials with a high degree of crystalline perfection. Studies conducted at CAMMP (Center for Advanced Microgravity Materials Processing) have demonstrated that microgravity processing can produce larger crystal sizes and fewer structural defects relative to terrestrial crystal growth. Principal Investigator: Dr. Albert Sacco

  7. Kinetics of Copper Adsorption from Effluent Stream by ZeoliteNaX

    NASA Astrophysics Data System (ADS)

    Singh, Surinder; Sambi, S. S.; Sharma, S. K.; Pandey, Pankaj Kumar

    2010-06-01

    The batch experiments were conducted to study the copper (II) removal by ZeoliteNaX at temperature of 288+1 K, adsorbent dose of 2 g/L and contact time of 24 hour. Effects of pH, temperature, contact time and Cu (II) ion concentration by the adsorbent were investigated. The data were analyzed using the Langmuir, Freundlich and Temkin isotherms. Freundlich isotherm was found to correlate the adsorption of Cu (II) better and the mono-layer adsorption capacity for Cu (II) removal was 41.6 mg/g. The adsorbed amounts of Cu (II) reached equilibrium within 150 minutes. The four adsorption kinetic models namely, the first order equation, second order equations, pseudo-first order equation and pseudo second-order equations were also tested to fit the data. The pseudo-first-order equation was found to fit best for the experimental data. Thermodynamic analysis indicated the spontaneous and endothermic nature of the adsorption of Cu (II) by ZeoliteNaX.

  8. Tailoring the Transport Properties of Zeolitic Imidazolate Frameworks by Post-Synthetic Thermal Modification.

    PubMed

    Zhang, Chen; Koros, William J

    2015-10-28

    Understanding how to control transport properties of zeolitic imidazolate frameworks (ZIFs) is critical to extend ZIF-based membranes and adsorbents to a wide spectrum of gas and vapor separations. In this work, we report a facile post-synthetic thermal modification (PSTM) technique to tailor ZIFs' transport properties by balancing diffusivity and diffusion selectivity. With controllable dissociation of framework methyl groups from a precursor ZIF (ZIF-8), we have prepared thermally modified ZIFs showing substantially increased n-butane diffusivity and attractive n/iso-butane diffusion selectivity. Hybrid ZIF/polymer mixed-matrix membranes formed using these thermally modified ZIFs are expected to deliver attractive butane isomer separation performance. Membranes based on such materials can potentially be used to retrofit refinery alkylation units for producing premium gasoline blending stocks. PMID:26451850

  9. Optimizing anti-coking abilities of zeolites by ethylene diamine tetraacetie acid modification on catalytic fast pyrolysis of corn stalk

    NASA Astrophysics Data System (ADS)

    Zhang, Bo; Zhong, Zhaoping; Song, Zuwei; Ding, Kuan; Chen, Paul; Ruan, Roger

    2015-12-01

    In order to minimize coke yield during biomass catalytic fast pyrolysis (CFP) process, ethylene diamine tetraacetie acid (EDTA) chemical modification method is carried out to selectively remove the external framework aluminum of HZSM-5 catalyst. X-ray diffraction (XRD), nitrogen (N2)-adsorption and ammonia-temperature programmed desorption (NH3-TPD) techniques are employed to investigate the porosity and acidity characteristics of original and modified HZSM-5 samples. Py-GC/MS and thermo-gravimetric analyzer (TGA) experiments are further conducted to explore the catalytic effect of modified HZSM-5 samples on biomass CFP and to verify the positive effect on coke reduction. Results show that EDTA treatment does not damage the crystal structure of HZSM-5 zeolites, but leads to a slight increase of pore volume and pore size. Meanwhile, the elimination of the strong acid peak indicates the dealumination of outer surface of HZSM-5 zeolites. Treatment time of 2 h (labeled EDTA-2H) is optimal for acid removal and hydrocarbon formation. Among all modified catalysts, EDTA-2H performs the best for deacidification and can obviously increase the yields of positive chemical compositions in pyrolysis products. Besides, EDTA modification can improve the anti-coking properties of HZSM-5 zeolites, and EDTA-2H gives rise to the lowest coke yield.

  10. Chemical Modification of Tb@C82 by Copper(I)-Catalyzed Cycloadditions

    E-print Network

    Wang, Jianbo

    Chemical Modification of Tb@C82 by Copper(I)-Catalyzed Cycloadditions Lai Feng, Xiaomei Zhang properties of EMF and provided the means of multiple functionalization for EMF. Herein, a copper(I) catalyst (Cu(MeCN)4PF6)9 mediated reaction of Tb@C82 with R-diazocarbonyl compounds (1 in Scheme 1) to produce

  11. Modification of surface properties of copper-refractory metal alloys

    DOEpatents

    Verhoeven, J.D.; Gibson, E.D.

    1993-10-12

    The surface properties of copper-refractory metal (CU-RF) alloy bodies are modified by heat treatments which cause the refractory metal to form a coating on the exterior surfaces of the alloy body. The alloys have a copper matrix with particles or dendrites of the refractory metal dispersed therein, which may be niobium, vanadium, tantalum, chromium, molybdenum, or tungsten. The surface properties of the bodies are changed from those of copper to that of the refractory metal.

  12. Natrolite zeolite supported copper nanoparticles as an efficient heterogeneous catalyst for the 1,3-diploar cycloaddition and cyanation of aryl iodides under ligand-free conditions.

    PubMed

    Nasrollahzadeh, Mahmoud; Sajadi, S Mohammad; Rostami-Vartooni, Akbar; Khalaj, Mehdi

    2015-09-01

    In this paper, we report the preparation of Natrolite zeolite supported copper nanoparticles as a heterogeneous catalyst for 1,3-diploar cycloaddition and synthesis aryl nitriles from aryl iodides under ligand-free conditions. The catalyst was characterized using XRD, SEM, TEM, EDS and TG-DTA. The experimental procedure is simple, the products are formed in high yields and the catalyst can be recycled and reused several times without any significant loss of catalytic activity. PMID:25988488

  13. Surface modification of calcium-copper hydroxyapatites using polyaspartic acid

    NASA Astrophysics Data System (ADS)

    Othmani, Masseoud; Aissa, Abdallah; Bachoua, Hassen; Debbabi, Mongi

    2013-01-01

    Mixed calcium-copper hydroxyapatite (Ca-CuHAp), with general formula Ca(10-x)Cux(PO4)6(OH)2, where 0 ? x ? 0.75 was prepared in aqueous medium in the presence of different concentrations of poly-L-aspartic acid (PASP). XRD, IR, TG-DTA, TEM-EDX, AFM and chemical analyses were used to characterize the structure, morphology and composition of the products. All techniques show the formation of new hybrid compounds Ca-CuHAp-PASP. The presence of the grafting moiety on the apatitic material is more significant with increasing of copper amount and/or organic concentration in the starting solution. These increases lead to the affectation of apatite crystallinity. The IR spectroscopy shows the conservation of (Psbnd OH) band of (HPO4)2- groups, suggesting that PASP acid was interacted only with metallic cations of hydroxyapatite.

  14. Modification of commercial NaY zeolite to give high water diffusivity and adsorb a large amount of water.

    PubMed

    Katoh, Masahiro; Kimura, Michisato; Sugino, Mao; Horikawa, Toshihide; Nakagawa, Keizo; Sugiyama, Shigeru

    2015-10-01

    By using NaY zeolites as desiccant materials, commercial NaY zeolite was alkali treated with 1 M NaOH aqueous solution and then Mg(2+) ion-exchanged by 0.5 M Mg(NO3)2 aqueous solution. Alkali treatment (AT) of NaY zeolite removed silicon atoms selectivity from the framework of Y-type zeolite and enhanced water diffusivity of Y-type zeolite. On the other hand, Mg(2+) ion-exchange of NaY zeolite increased the amount of water adsorbed. Prepared Y-AT-Mg zeolite had both water adsorption velocity and a large difference of water adsorbed amount between adsorption at 30 °C and desorption at 100 °C. PMID:26072446

  15. Preparation and characterization of surfactant-modified hydroxyapatite/zeolite composite and its adsorption behavior toward humic acid and copper(II).

    PubMed

    Zhan, Yanhui; Lin, Jianwei; Li, Jia

    2013-04-01

    A novel composite material, i.e., surfactant-modified hydroxyapatite/zeolite composite, was used as an adsorbent to remove humic acid (HA) and copper(II) from aqueous solution. Hydroxyapatite/zeolite composite (HZC) and surfactant-modified HZC (SMHZC) were prepared and characterized by X-ray diffraction, Fourier transform infrared spectroscopy, and field emission scanning electron microscope. The adsorption of HA and copper(II) on SMHZC was investigated. For comparison purposes, HA adsorption onto HZC was also investigated. SMHZC exhibited much higher HA adsorption capacity than HZC. The HA adsorption capacity for SMHZC decreased slightly with increasing pH from 3 to 8 but decreased significantly with increasing pH from 8 to 12. The copper(II) adsorption capacity for SMHZC increased with increasing pH from 3 to 6.5. The adsorption kinetic data of HA and copper(II) on SMHZC obeyed a pseudo-second-order kinetic model. The adsorption of HA and copper(II) on SMHZC took place in three different stages: fast external surface adsorption, gradual adsorption controlled by both film and intra-particle diffusions, and final equilibrium stage. The equilibrium adsorption data of HA on SMHZC better fitted to the Langmuir isotherm model than the Freundlich isotherm model. The equilibrium adsorption data of copper(II) on SMHZC could be described by the Langmuir, Freundlich, and Dubinin-Radushkevich isotherm models. The presence of copper(II) in solution enhanced HA adsorption onto SMHZC. The presence of HA in solution enhanced copper(II) adsorption onto SMHZC. The mechanisms for the adsorption of HA on SMHZC at pH 7 may include electrostatic attraction, organic partitioning, hydrogen bonding, and Lewis acid-base interaction. The mechanisms for the adsorption of copper(II) on SMHZC at pH 6 may include surface complexation, ion exchange, and dissolution-precipitation. The obtained results indicate that SMHZC can be used as an effective adsorbent to simultaneously remove HA and copper(II) from water. PMID:22961484

  16. Local ammonia storage and ammonia inhibition in a monolithic copper-beta zeolite SCR catalyst

    SciTech Connect

    Auvray, Xavier P; Partridge Jr, William P; Choi, Jae-Soon; Pihl, Josh A; Yezerets, Alex; Kamasamudram, Krishna; Currier, Neal; Olsson, Louise

    2012-01-01

    Selective catalytic reduction of NO with NH{sub 3} was studied on a Cu-beta zeolite catalyst, with specific focus on the distributed NH{sub 3} capacity utilization and inhibition. In addition, several other relevant catalyst parameter distributions were quantified including the SCR zone, or catalyst region where SCR occurs, and NO and NH{sub 3} oxidation. We show that the full NH{sub 3} capacity (100% coverage) is used within the SCR zone for a range of temperatures. By corollary, unused NH{sub 3} capacity exists downstream of the SCR zone. Consequently, the unused capacity relative to the total capacity is indicative of the portion of the catalyst unused for SCR. Dynamic NH{sub 3} inhibition distributions, which create local transient conversion inflections, are measured. Dynamic inhibition is observed where the gas phase NH{sub 3} and NO concentrations are high, driving rapid NH{sub 3} coverage buildup and SCR. Accordingly, we observe dynamic inhibition at low temperatures and in hydrothermally aged states, but predict its existence very near the catalyst front in higher conversion conditions where we did not specifically monitor its impact. While this paper addresses some general distributed SCR performance parameters including Oxidation and SCR zone, our major new contributions are associated with the NH{sub 3} capacity saturation within the SCR zone and dynamic inhibition distributions and the associated observations. These new insights are relevant to developing accurate models, designs and control strategies for automotive SCR catalyst applications.

  17. Surface Modification of Boron-Doped Diamond with Microcrystalline Copper Phthalocyanine: Oxygen Reduction Catalysis.

    PubMed

    Gan, Patrick; Foord, John S; Compton, Richard G

    2015-10-01

    Surface modification of boron-doped diamond (BDD) with copper phthalocyanine was achieved using a simple and convenient dropcast deposition, giving rise to a microcrystalline structure. Both unmodified and modified BDD electrodes of different surface terminations (namely hydrogen and oxygen) were compared via the electrochemical reduction of oxygen in aqueous solution. A significant lowering of the cathodic overpotential by about 500?mV was observed after modification of hydrogen-terminated (hydrophobic) diamond, while no voltammetric peak was seen on modified oxidised (hydrophilic) diamond, signifying greater interaction between copper phthalocyanine and the hydrogen-terminated BDD. Oxygen reduction was found to undergo a two-electron process on the modified hydrogen-terminated diamond, which was shown to be also active for the reduction of hydrogen peroxide. The lack of a further conversion of the peroxide was attributed to its rapid diffusion away from the triple phase boundary at which the reaction is expected to exclusively occur. PMID:26491640

  18. Surface Modification of Boron-Doped Diamond with Microcrystalline Copper Phthalocyanine: Oxygen Reduction Catalysis

    PubMed Central

    Gan, Patrick; Foord, John S; Compton, Richard G

    2015-01-01

    Surface modification of boron-doped diamond (BDD) with copper phthalocyanine was achieved using a simple and convenient dropcast deposition, giving rise to a microcrystalline structure. Both unmodified and modified BDD electrodes of different surface terminations (namely hydrogen and oxygen) were compared via the electrochemical reduction of oxygen in aqueous solution. A significant lowering of the cathodic overpotential by about 500?mV was observed after modification of hydrogen-terminated (hydrophobic) diamond, while no voltammetric peak was seen on modified oxidised (hydrophilic) diamond, signifying greater interaction between copper phthalocyanine and the hydrogen-terminated BDD. Oxygen reduction was found to undergo a two-electron process on the modified hydrogen-terminated diamond, which was shown to be also active for the reduction of hydrogen peroxide. The lack of a further conversion of the peroxide was attributed to its rapid diffusion away from the triple phase boundary at which the reaction is expected to exclusively occur. PMID:26491640

  19. Conversion of trypsin to a copper enzyme: tyrosinase/catechol oxidase by chemical modification.

    PubMed

    Okutucu, Burcu; Zeytunluoglu, Ali; Zihnioglu, Figen

    2010-01-01

    New active sites can be introduced into naturally occurring enzymes by the chemical modification of specific amino acid residues in concert with genetic techniques. Chemical strategies have had a significant impact in the field of enzyme design such as modifying the selectivity and catalytic activity which is very different from those of the corresponding native enzymes. Thus, chemical modification has been exploited for the incorporation of active site binding analogs onto protein templates and for atom replacement in order to generate new functionality such as the conversion of a hydrolase into a peroxidase. The introduction of a coordination complex into a substrate binding pocket of trypsin could probably also be extended to various enzymes of significant therapeutic and biotechnological importance. The aim of this study is the conversion of trypsin into a copper enzyme: tyrosinase by chemical modification. Tyrosinase is a biocatalyst (EC.1.14.18.1) containing two atoms of copper per active site with monooxygenase activity. The active site of trypsin (EC 3.4.21.4), a serine protease was chemically modified by copper (Cu(+2)) introduced p-aminobenzamidine (pABA- Cu(+2): guanidine containing schiff base metal chelate) which exhibits affinity for the carboxylate group in the active site as trypsin-like inhibitor. Trypsin and the resultant semisynthetic enzyme preparation was analysed by means of its trypsin and catechol oxidase/tyrosinase activity. After chemical modification, trypsin-pABA-Cu(+2) preparation lost 63% of its trypsin activity and gained tyrosinase/catechol oxidase activity. The kinetic properties (K(cat), K(m), K(cat)/K(m)), optimum pH and temperature of the trypsin-pABA-Cu(+2) complex was also investigated. PMID:20024799

  20. Ion-beam-induced modifications in the structural and electrical properties of copper oxide selenite nanowires

    NASA Astrophysics Data System (ADS)

    Rana, Pallavi; Chauhan, R. P.

    2015-04-01

    Irradiation with swift heavy ions (SHIs) with energy in the MeV range is a unique tool for engineering the properties of materials. In this context, the objective of the present work is to study the conduction of charge carriers in pre- and post-ion-irradiated semiconducting nanowires. Copper oxide selenite nanowires were synthesized using a template-assisted electrodeposition technique from an aqueous solution of 0.8 M CuSO4·5H2O and 8 mM SeO2. The synthesized nanowires were observed to have a monoclinic structure with linear I-V characteristics (IVC). The effect of irradiation with 160 MeV Ni+12 ions on the properties of the copper oxide selenite nanowires was investigated for fluences varying from 1011 to 1013 ions/cm2. XRD spectra confirmed no change in the phase of the swift-heavy-ion-irradiated nanowires, but a modification in the orientation of the planes was observed that depended on the ion fluence. The electrical resistivity of the semiconducting nanowires also varied with the ion fluence. Simultaneous irradiation-induced modifications to the electro-chemical potential gradient and the granular properties of the material may have been the origin of the alteration in the structural and electrical properties of the nanowires.

  1. Copper(I)-Y Zeolite-Catalyzed Regio- and Stereoselective [2 + 2 + 2] Cyclotrimerization Cascade: An Atom- and Step-Economical Synthesis of Pyrimido[1,6-a]quinoline.

    PubMed

    Ramanathan, Devenderan; Pitchumani, Kasi

    2015-10-16

    An elegant copper(I)-Y zeolite-catalyzed tandem process, involving ketenimine-based termolecular [2 + 2 + 2]/[NC + CC + NC] cycloaddition, using sulfonyl azide, alkyne, and quinoline, to prepare pyrimido[1,6-a]quinolines is reported. In this straightforward, highly atom- and step-economical protocol, copper(I) promotes for azide-alkyne [3 + 2] cycloaddition which is followed by ring-rearrangement/ketenimine formation/regio- and stereoselective [2 + 2 + 2] termolecular cycloaddition and dehydrogenation cascade to yield selectively the E-isomer of pyrimido[1,6-a]quinoline. PMID:26390020

  2. Position-dependent performance of copper phthalocyanine based field-effect transistors by gold nanoparticles modification.

    PubMed

    Luo, Xiao; Li, Yao; Lv, Wenli; Zhao, Feiyu; Sun, Lei; Peng, Yingquan; Wen, Zhanwei; Zhong, Junkang; Zhang, Jianping

    2015-01-21

    A facile fabrication and characteristics of copper phthalocyanine (CuPc)-based organic field-effect transistor (OFET) using the gold nanoparticles (Au NPs) modification is reported, thereby achieving highly improved performance. The effect of Au NPs located at three different positions, that is, at the SiO2/CuPc interface (device B), embedding in the middle of CuPc layer (device C), and on the top of CuPc layer (device D), is investigated, and the results show that device D has the best performance. Compared with the device without Au NPs (reference device A), device D displays an improvement of field-effect mobility (?(sat)) from 1.65 × 10(-3) to 5.51 × 10(-3) cm(2) V(-1) s(-1), and threshold voltage decreases from -23.24 to -16.12 V. Therefore, a strategy for the performance improvement of the CuPc-based OFET with large field-effect mobility and saturation drain current is developed, on the basis of the concept of nanoscale Au modification. The model of an additional electron transport channel formation by FET operation at the Au NPs/CuPc interface is therefore proposed to explain the observed performance improvement. Optimum CuPc thickness is confirmed to be about 50 nm in the present study. The device-to-device uniformity and time stability are discussed for future application. PMID:25548878

  3. Sorption Kinetics Of Selected Heavy Metals Adsorption To Natural And Fe(III) Modified Zeolite Tuff Containing Clinoptilolite Mineral

    NASA Astrophysics Data System (ADS)

    Sirotiak, Maroš; Lipovský, Marek; Bartošová, Alica

    2015-06-01

    In the research described in this paper, studied was sorption capacity of natural and ferric modification of zeolite tuff containing mineral clinoptilolite from the Nižný Hrabovec deposit to remove potentially toxic metals (ionic forms of chromium, nickel, copper and aluminium) from their water solutions. We reported that the Fe (III) zeolite has an enhanced ability to sorption of Cu (II), and a slight improvement occurs in the case of Cr (VI) and Ni (II). On the other hand, the deterioration was observed in the case of Al (III) adsorption.

  4. COPPER

    EPA Science Inventory

    The report is a review of current knowledge of the distribution of copper in the environment and living things. Metabolism and the effects of copper in the biosphere are also considered. Copper compounds are common and widely distributed in nature. They are also extensively mined...

  5. Thermal behavior of natural zeolites

    SciTech Connect

    Bish, D.L.

    1993-09-01

    Thermal behavior of natural zeolites impacts their application and identification and varies significantly from zeolite to zeolite. Zeolites evolve H{sub 2}0 upon heating, but recent data show that distinct ``types`` of water (e.g., loosely bound or tightly bound zeolitic water) do not exist. Rather water is bound primarily to extra-framework cations with a continuum of energies, giving rise to pseudocontinuous loss of water accompanied by a dynamic interaction between remaining H{sub 2}0 molecules and extra-framework cations. These interactions in the channels of zeolites give rise to dehydration dependent on the extra-framework cation, in addition to temperature and water vapor pressure. The dehydration reaction and the extra-framework cation also affect the thermal expansion/contraction. Most zeolites undergo dehydration-induced contractions that may be anisotropic, although minor thermal expansion can be seen with some zeolites. Such contractions can be partially or completely irreversible if they involve modifications of the tetrahedral framework and/or if rehydration is sluggish. Thermally induced structural modifications are also driven initially by dehydration and the concomitant contraction and migration of extra-framework cations. Contraction is accommodated by rotations of structural units and tetrahedral cation-oxygen linkages may break. Thermal reactions that involve breaking of tetrahedral cation-oxygen bonds markedly irreversible and may be kinetically limited, producing large differences between short- and long-term heating.

  6. Two-dimensional zeolite-like network in the new caesium copper aluminate Cs2CuAl4O8.

    PubMed

    Shvanskaya, Larisa; Yakubovich, Olga; Massa, Werner; Vasiliev, Alexander

    2015-10-01

    Monoclinic dicaesium copper tetraaluminate, Cs2CuAl4O8, space group P21/c, a = 8.4551?(7), b = 10.012?(1), c = 17.073?(2)?Å, ? = 101.643?(9)°, Z = 6, was obtained by high-temperature crystallization from a phosphate flux. Its microporous crystal structure presents the first example of double layers built from [AlO4] tetrahedra combined in 4-, 6- and 8-rings, topologically similar to those found in the ATT-type zeolites and isostructural minerals armstrongite, davanite and dalyite. These layers show a rare arrangement of three [AlO4] tetrahedra sharing one oxygen vertex. The aluminate slabs are further linked by chains of edge-sharing [CuO4] square planes to form a mixed anionic three-dimensional framework with Cs(+) cations in channels and cavities. An unusually short Cu...Cs distance of 3.166?Å is ascribed to the strong Jahn-Teller effect of Cu(2+). The magnetic subsystem demonstrates properties of an alternating antiferromagnetic chain with a gap in the spectrum of magnetic excitations. PMID:26428399

  7. Luminescent materials derived from the surface-modification of Ln3+-doped zeolite L with a silylated terpyridine

    NASA Astrophysics Data System (ADS)

    Qin, Zhiqiao; Li, Hongshi; Wang, Yige

    2014-11-01

    Herein we report luminescent materials of Ln3+ (Ln = Eu or Tb) doped disc shaped zeolite L crystals (Eu3+/ZLD, Tb3+/ZLD) modified with a silylated terpyridine (Terpy-Si). The modified crystals show bright red emission and green emission under UV-light irradiation due to the energy transfer from the Terpy-Si to the Eu3+ and Tb3+ ions. The obtained materials were characterized with FT-IR, SEM, XRD and elemental analysis. Luminescence spectroscopy was used to study the luminescence properties of the modified Eu3+(Tb3+)/ZLD crystals. The formation of europium(III) and terbium(III) Terpy-Si silicon complexes and energy transfer from Terpy-Si to Eu3+ ions and Tb3+ have been confirmed by luminescence spectroscopy.

  8. A novel cysteine sensor based on modification of carbon paste electrode by Fe(II)-exchanged zeolite X nanoparticles.

    PubMed

    Hashemi, Habibeh-Sadat; Nezamzadeh-Ejhieh, Alireza; Karimi-Shamsabadi, Maryam

    2016-01-01

    An electrochemical sensor based on carbon paste electrode (CPE) modified with iron(II) doped into a synthesized nano-particles of zeolite X (Fe(II)-NX/ZCME) was constructed, which is highly sensitive for detection of cysteine (Cys). The modified electrode showed an excellent electro-activity for oxidation of Cys in phosphate buffer at pH7.4. It has been found that anodic peak potential of Cys oxidation, compared with the unmodified CPE (UCPE), was shifted towards negative values at the surface of the modified electrode under the optimum condition. The peak current increased linearly with the Cys concentration in the wide range of 5.0×10(-9)-3.0×10(-3)molL(-1). The very low detection limit was obtained to be 1.5×10(-10)molL(-1). Finally, the modified electrode was used as a selective, simple and precise new electrochemical sensor for the determination of Cys in the real samples, such as pharmaceutical and biological fluids. PMID:26478313

  9. Modification of soil microbial activity and several hydrolases in a forest soil artificially contaminated with copper

    NASA Astrophysics Data System (ADS)

    Bellas, Rosa; Leirós, M? Carmen; Gil-Sotres, Fernando; Trasar-Cepeda, Carmen

    2010-05-01

    Soils have long been exposed to the adverse effects of human activities, which negatively affect soil biological activity. As a result of their functions and ubiquitous presence microorganisms can serve as environmental indicators of soil pollution. Some features of soil microorganisms, such as the microbial biomass size, respiration rate, and enzyme activity are often used as bioindicators of the ecotoxicity of heavy metals. Although copper is essential for microorganisms, excessive concentrations have a negative influence on processes mediated by microorganisms. In this study we measured the response of some microbial indicators to Cu pollution in a forest soil, with the aim of evaluating their potential for predicting Cu contamination. Samples of an Ah horizon from a forest soil under oakwood vegetation (Quercus robur L.) were contaminated in the laboratory with copper added at different doses (0, 120, 360, 1080 and 3240 mg kg-1) as CuCl2×2H2O. The soil samples were kept for 7 days at 25 °C and at a moisture content corresponding to the water holding capacity, and thereafter were analysed for carbon and nitrogen mineralization capacity, microbial biomass C, seed germination and root elongation tests, and for urease, phosphomonoesterase, catalase and ß-glucosidase activities. In addition, carbon mineralization kinetics were studied, by plotting the log of residual C against incubation time, and the metabolic coefficient, qCO2, was estimated. Both organic carbon and nitrogen mineralization were lower in polluted samples, with the greatest decrease observed in the sample contaminated with 1080 mg kg-1. In all samples carbon mineralization followed first order kinetics; the C mineralization constant was lower in contaminated than in uncontaminated samples and, in general, decreased with increasing doses of copper. Moreover, it appears that copper contamination not only reduced the N mineralization capacity, but also modified the N mineralization process, since in the contaminated samples all of the inorganic nitrogen was present as ammonium, probably because of inhibition of nitrification. There was a marked decrease in biomass-C with addition of copper, and the decrease was more acute at intermediate doses (average decrease, 73%). Despite the decreases in microbial biomass and mineralized C, the value of qCO2 increased after the addition of copper. Urease activity was strongly affected by the presence of copper and the decrease was proportional to the dose; the activity at the highest dose was only 96% of that in the uncontaminated sample. Phosphomonoesterase activity was also affected by addition of copper; the reduction in activity was less than for urease and the greatest reduction was observed for the dose of 1080 mg kg-1 of copper. Catalase activity was affected by the contamination, but no clear trend was observed in relation to the dose of copper. ß-glucosidase was scarcely modified by the contamination but an increase in activity was observed at the highest dose of copper. Seed germination was not affected by copper contamination, since it only showed a clear decrease for the sample contaminated with the highest dose of copper, while root elongation decreased sharply with doses higher than 120 mg kg-1 of copper. The combined germination-elongation index followed a similar pattern to that of root elongation. For all investigated properties showing a reduction of more than 50%, the response to copper contamination was fitted to a sigmoidal dose-response model, in order to estimate the ED50 values. The ED50 values were calculated for microbial biomass, urease, root elongation and germination-elongation index, and similar values were obtained, ranging from 340 to 405 mg kg-1 Cu. The ED50 values may therefore provide a good estimation of soil deterioration.

  10. Copper

    Integrated Risk Information System (IRIS)

    Copper ; CASRN 7440 - 50 - 8 Human health assessment information on a chemical substance is included in the IRIS database only after a comprehensive review of toxicity data , as outlined in the IRIS assessment development process . Sections I ( Health Hazard Assessments for Noncarcinogenic Effects )

  11. Chemical Zeolites Combinatorial . . .

    E-print Network

    Servatius, Brigitte

    . Chemical Zeolites · crystalline solid · units: Si + 4O Si O O O O · two covalent bonds per oxygen #12Chemical Zeolites Combinatorial . . . Realization 2d Zeolites Finite Zeolites The Layer . . . Holes University (Brigitte Servatius -- WPI) #12;Chemical Zeolites Combinatorial . . . Realization 2d Zeolites

  12. Design and modification of zeolite capsule catalyst, a confined reaction field, and its application in one-step isoparaffin synthesis from syngas

    SciTech Connect

    Guohui Yang; Jingjiang He; Yi Zhang; Yoshiharu Yoneyama; Yisheng Tan; Yizhuo Han; Tharapong Vitidsant; Noritatsu Tsubaki

    2008-05-15

    Four kinds of zeolite capsule catalyst with different crystallization conditions were prepared and utilized for the middle isoparaffin direct synthesis via Fischer-Tropsch synthesis (FTS) reaction. Characterization results exhibited that these capsule catalysts had a compact, integral H-ZSM-5 shell. In FTS reactions on these zeolite capsule catalysts, hydrocarbons of C11+ were totally suppressed, accompanied by a sharp anti-Anderson-Schultz-Flory (ASF) law product distribution. The selectivity of light isoparaffin was improved obviously, but with the increase of the olefin's selectivity. Two-stage isoparaffin synthesis reaction, using the combination of zeolite capsule catalyst with hydrogenation catalyst of Pd/SiO{sub 2} in a single reactor as dual-bed catalyst, was also conducted for converting the residual olefins produced by the single zeolite capsule catalyst. Dependent on the palladium role of hydrogenation and hydrogen spillover, almost all the olefins effused from the first stage of zeolite capsule catalyst were hydrogenated, mostly converted to isoparaffin. The selectivity of isoparaffin in the final products was increased markedly as expected. 10 refs., 7 figs., 2 tabs.

  13. Systematic analysis and modification of embedded-atom potentials: case study of copper

    NASA Astrophysics Data System (ADS)

    Jalkanen, Jari; Müser, Martin H.

    2015-10-01

    In this study, we evaluate the functionals of different embedded-atom methods (EAM) by fitting their free parameters to ab-initio results for copper. Our emphasis lies on testing the transferability of the potentials between systems which vary in their spatial dimension and geometry. The model structures encompass zero-dimensional clusters, one-dimensional chains, two-dimensional tilings, and three-dimensional bulk systems. To avoid having to mimic charge transfer, which is outside the scope of conventional EAM potentials, we focus on structures, in which all atoms are symmetrically equivalent. We find that the simple, four-parameter Gupta EAM potential is overall satisfactory. Adding complexity to it decreases the errors on our set of structures only by marginal amounts, unless EAM is modified to depend also on density gradients, higher-order derivatives, or related terms. All tested conventional EAM functions reveal similar problems: the binding energy of closed-packed systems is overestimated in comparison to open or planar geometries, and structures with small coordination tend to be too rigid. These deficiencies can be fixed in terms of a systematically modified embedded-atom method (SMEAM), which reproduces DFT results on bond lengths, binding energies, and stiffnesses or bulk moduli by typically O(1%), O(5%), and O(15%) accuracy, respectively. SMEAM also predicts the radial distribution function of liquid copper quite accurately. Yet, it does not overcome the difficulty to reproduce the elastic tensor elements of a hypothetical diamond lattice.

  14. An improved performance of copper phthalocyanine OFETs with channel and source/drain contact modifications

    NASA Astrophysics Data System (ADS)

    Huanqin, Dang; Xiaoming, Wu; Xiaowei, Sun; Runqiu, Zou; Ruochuan, Zhang; Shougen, Yin

    2015-10-01

    We report an effective method to improve the performance of p-type copper phthalocyanine (CuPc) based organic field-effect transistors (OFETs) by employing a thin para-quaterphenyl (p-4p) film and simultaneously applying V2O5 to the source/drain regions. The p-4p layer was inserted between the insulating layer and the active layer, and V2O5 layer was added between CuPc and Al in the source–drain (S/D) area. As a result, the field-effect saturation mobility and on/off current ratio of the optimized device were improved to 5 × 10?2 cm2/(V·s) and 104, respectively. We believe that because p-4p could induce CuPc to form a highly oriented and continuous film, this resulted in the better injection and transport of the carriers. Moreover, by introducing the V2O5 electrode's modified layers, the height of the carrier injection barrier could be effectively tuned and the contact resistance could be reduced. Project supported by the National Natural Science Foundation of China (No. 60676051), the National High Technology Research and Development Program of China (No. 2013A A014201), the Scientific Developing Foundation of Tianjin Education Commission (No. 2011ZD02), the Key Science and Technology Support Program of Tianjin (No. 14ZCZDGX00006), and the Foundation of Key Discipline of Material Physics and Chemistry of Tianjin.

  15. Modification research on in wall of capillary copper tube with Norland optical adhesive 68 in a double stereo PCR microfluidic chip.

    PubMed

    Wu, J; Wang, F J; Wang, C Y; Yu, K X; Ma, Y; Chen, T; Li, Y H; Zheng, Y

    2015-01-01

    In this study, a Norland optical adhesive 68 (NOA68) film, approximately 2.2 ?m thick, was manufactured using ultraviolet solidified NOA68 in apparatus manufacturing film on the inwall of a capillary copper pipe, developed in our laboratory. The roughness of the inwall of capillary copper pipe was improved from Ra = 0.766 to 0.204 ?m and the contact angle was improved from approximately 96° to 55°, increasing hydrophilicity. Polymerase chain reaction experiments indicated that the ratio of work pressure in the microfluidic chip before modification to that after modification was 2.71/1, indicating that the extension efficiency increased. Our results provide a basis for the construction of a microform chip based on function integration. PMID:26535674

  16. Interfacial studies of bimetallic corrosion in copper/ruthenium systems and silicon surface modification with organic and organometallic chemistry

    NASA Astrophysics Data System (ADS)

    Nalla, Praveen Reddy

    To form Cu interconnects, dual-damascene techniques like chemical mechanical planarization (CMP) and post-CMP became inevitable for removing the "overburden" Cu and for planarizing the wafer surface. During the CMP processing, Cu interconnects and barrier metal layers experience different electrochemical interactions depending on the slurry composition, pH, and ohmic contact with adjacent metal layers that would set corrosion process. Ruthenium as a replacement of existing diffusion barrier layer will require extensive investigation to eliminate or control the corrosion process during CMP and post CMP. Bimetallic corrosion process was investigated in the ammonium citrate (a complexing agent of Cu in CMP solutions) using micro test patterns and potentiodynamic measurements. The enhanced bimetallic corrosion of copper observed is due to noble behavior of the ruthenium metal. Cu formed Cu(II)-amine and Cu(Il)citrate complexes in alkaline and acidic solutions and a corrosion mechanism has been proposed. The currently used metallization process (PVD, CVD and ALD) require ultra-high vacuum and are expensive. A novel method of Si surface metallization process is discussed that can be achieved at room temperature and does not require ultra-high vacuum. Ruthenation of Si surface through strong Si-Ru covalent bond formation is demonstrated using different ruthenium carbonyl compounds. RBS analysis accounted for monolayer to sub-monolayer coverage of Si surface. Interaction of other metal carbonyl (like Fe, Re, and Rh) is also discussed. The silicon (111) surface modifications with vinyl terminated organic compounds were investigated to form self-assembled monolayers (SAMs) and there after these surfaces were further functionalized. Acrylonitrile and vinylbenzophenone were employed for these studies. Ketone group of vinylbenzophenone anchored to Si surface demonstrated reactivity with reducing and oxidizing agents.

  17. Simultaneous SO{sub 2}/NO{sub x} abatement using zeolite-supported copper. Quarterly progress report, January 1, 1995--March 31, 1995

    SciTech Connect

    Mitchell, M.B.; White, M.G.

    1995-12-01

    We have significantly improved on our earlier results with a copper-impregnated alumina, obtaining reproducible results for the impregnation procedure and linear behavior with solution concentration of the precursor. The copper acetylacetonate precursor is adsorbed molecularly onto the alumina surface, with no noticeable decomposition. The adsorbed complex appears to form layers on the alumina surface, similar to results found using the same complex with a silica substrate. The materials start out as light blue powders, and after oxidation are light green. Using infrared spectroscopy, we have examined the in situ adsorption and oxidation of SO{sub 2} on the oxidized sorbent, which is dispersed copper oxide supported on aluminum oxide, and have observed that the initial species formed correspond to aluminum sulfate and aluminum sulfate. The sulfate is formed at temperatures much lower than similar experiments studying SO{sub 2} adsorption on alumina and sodium-doped alumina. As a result of oxidation, the adsorbed sulfur species, which begin as aluminum sulfate and sulfate, are converted to copper sulfate.

  18. Modification of the near-surface layers of a copper foil under the action of a volume gas discharge in air at atmospheric pressure

    NASA Astrophysics Data System (ADS)

    Shulepov, M. A.; Tarasenko, V. F.; Goncharenko, I. M.; Koval', N. N.; Kostyrya, I. D.

    2008-04-01

    We have studied the modification of the near-surface layers of a copper foil under the action of a volume gas discharge, which was generated in air at atmospheric pressure by nanosecond high-voltage pulses of both negative and positive polarity applied between the foil and an electrode with a small radius of curvature. It is established that the surface layer of the discharge-treated copper foil in the central region is cleaned from carbon contaminations, while oxygen atoms penetrate in depth of the foil. The depth of a cleaned layer depends on the polarity of voltage pulses. For the positive voltage polarity on the foil, the cleaning takes place up to a depth exceeding 50 nm, while oxygen penetrates up to a depth of about 25 nm.

  19. Preparation of a Versatile Bifunctional Zeolite for Targeted Imaging Applications

    PubMed Central

    Ndiege, Nicholas; Raidoo, Renugan; Schultz, Michael K.; Larsen, Sarah

    2011-01-01

    Bifunctional zeolite Y was prepared for use in targeted in vivo molecular imaging applications. The strategy involved functionalization of the external surface of zeolite Y with chloropropyltriethoxysilane followed by reaction with sodium azide to form azide-functionalized NaY, which is amenable to copper(1) catalyzed click chemistry. In this study, a model alkyne (4-pentyn-1-ol) was attached to the azide-terminated surface via click chemistry to demonstrate feasibility for attachment of molecular targeting vectors (e.g., peptides, aptamers) to the zeolite surface. The modified particle efficiently incorporates the imaging radioisotope gallium-68 (68Ga) into the pores of the azide-functionalized NaY zeolite to form a stable bifunctional molecular targeting vector. The result is a versatile “clickable” zeolite platform that can be tailored for future in vivo molecular targeting and imaging modalities. PMID:21306141

  20. Simultaneous SO{sub 2}/NO{sub x} abatement using zeolite supported-copper. Progress report, April 1--June 30, 1996

    SciTech Connect

    Mitchell, M.B.; White, M.G.

    1996-12-31

    The authors have continued the investigation of the adsorption of NO on the Cu/{gamma}-alumina samples and have begun the study of the interaction of NO with sulfated Cu/{gamma}-alumina. The interaction of NO with a sulfated surface is extremely important, since the copper sites in the most popular NO reduction catalyst, Cu/ZAM-5, also adsorb SO{sub 2}, and the catalyst is poisoned by SO{sub 2}. It may be possible to determine whether the poisoning mechanism is due to a chemical effect, or some other effect, and investigate measures which might alleviate the deleterious effects of surface sulfation on the adsorption/reduction process. The results for NO interacting with the sulfated surface do not appear to result in the formation of any new species, but do show a dramatic change in the relative amounts of the NO species formed on the surface. The sulfation of the copper species apparently forces the copper species to remain as Cu{sup 2+}, which gives rise to a strong band at 1850 cm{sup {minus}1}, shifted to lower frequency from the 1863 cm{sup {minus}1} absorption found for the unsulfated catalyst, but which is still probably due to the formation of a Cu{sup 2+}/NO complex, given the small frequency shift. Two other infrared absorption bands observed for NO adsorbed on the un-sulfated catalyst are observed in the current study only weakly, and are due to the formation of adsorbed NO{sub 2}, the NO oxidation product formed when Cu{sup 2+} is reduced to Cu{sup +}, and to the Cu{sup +}/NO{sup {minus}} complex. The relatively intense absorption due to the Cu{sup 2+}/NO complex and the weak absorptions due to adsorbed NO{sub 2} and the Cu{sup +}/NO{sup {minus}} complex indicate that little reduction of the copper has taken place. Stabilization of the Cu species as Cu{sup 2+} by the sulfate apparently prevents participation of the surface copper species in the redox cycle. To the authors` knowledge this is the first reported infrared spectroscopic study of NO interacting with a sulfated Cu/{gamma}-alumina catalyst.

  1. Metal Oxide/Zeolite Combination Absorbs H2S

    NASA Technical Reports Server (NTRS)

    Voecks, Gerald E.; Sharma, Pramod K.

    1989-01-01

    Mixed copper and molybdenum oxides supported in pores of zeolite found to remove H2S from mixture of gases rich in hydrogen and steam, at temperatures from 256 to 538 degree C. Absorber of H2S needed to clean up gas streams from fuel processors that incorporate high-temperature steam reformers or hydrodesulfurizing units. Zeolites chosen as supporting materials because of their high porosity, rigidity, alumina content, and variety of both composition and form.

  2. ZEOLITES: EFFECTIVE WATER PURIFIERS

    EPA Science Inventory

    Zeolites are known for their adsorption, ion exchange and catalytic properties. Various natural zeolites are used as odor and moisture adsorbents and water softeners. Due to their acidic nature, synthetic zeolites are commonly employed as solid acid catalysts in petrochemical ind...

  3. Systems including catalysts in porous zeolite materials within a reactor for use in synthesizing hydrocarbons

    DOEpatents

    Rolllins, Harry W. (Idaho Falls, ID); Petkovic, Lucia M. (Idaho Falls, ID); Ginosar, Daniel M. (Idaho Falls, ID)

    2012-07-24

    Catalytic structures include a catalytic material disposed within a zeolite material. The catalytic material may be capable of catalyzing a formation of methanol from carbon monoxide and/or carbon dioxide, and the zeolite material may be capable of catalyzing a formation of hydrocarbon molecules from methanol. The catalytic material may include copper and zinc oxide. The zeolite material may include a first plurality of pores substantially defined by a crystal structure of the zeolite material and a second plurality of pores dispersed throughout the zeolite material. Systems for synthesizing hydrocarbon molecules also include catalytic structures. Methods for synthesizing hydrocarbon molecules include contacting hydrogen and at least one of carbon monoxide and carbon dioxide with such catalytic structures. Catalytic structures are fabricated by forming a zeolite material at least partially around a template structure, removing the template structure, and introducing a catalytic material into the zeolite material.

  4. Methods of using structures including catalytic materials disposed within porous zeolite materials to synthesize hydrocarbons

    DOEpatents

    Rollins, Harry W. (Idaho Falls, ID); Petkovic, Lucia M. (Idaho Falls, ID); Ginosar, Daniel M. (Idaho Falls, ID)

    2011-02-01

    Catalytic structures include a catalytic material disposed within a zeolite material. The catalytic material may be capable of catalyzing a formation of methanol from carbon monoxide and/or carbon dioxide, and the zeolite material may be capable of catalyzing a formation of hydrocarbon molecules from methanol. The catalytic material may include copper and zinc oxide. The zeolite material may include a first plurality of pores substantially defined by a crystal structure of the zeolite material and a second plurality of pores dispersed throughout the zeolite material. Systems for synthesizing hydrocarbon molecules also include catalytic structures. Methods for synthesizing hydrocarbon molecules include contacting hydrogen and at least one of carbon monoxide and carbon dioxide with such catalytic structures. Catalytic structures are fabricated by forming a zeolite material at least partially around a template structure, removing the template structure, and introducing a catalytic material into the zeolite material.

  5. Oxidative regeneration of toluene-saturated natural zeolite by gaseous ozone: the influence of zeolite chemical surface characteristics.

    PubMed

    Alejandro, Serguei; Valdés, Héctor; Manéro, Marie-Hélène; Zaror, Claudio A

    2014-06-15

    In this study, the effect of zeolite chemical surface characteristics on the oxidative regeneration of toluene saturated-zeolite samples is investigated. A Chilean natural zeolite (53% clinoptilolite, 40% mordenite and 7% quartz) was chemically modified by acid treatment with hydrochloric acid and by ion-exchange with ammonium sulphate. Thermal pre-treatments at 623 and 823K were applied and six zeolite samples with different chemical surface characteristics were generated. Chemical modification of natural zeolite followed by thermal out-gassing allows distinguishing the role of acidic surface sites on the regeneration of exhausted zeolites. An increase in Brønsted acid sites on zeolite surface is observed as a result of ammonium-exchange treatment followed by thermal treatment at 623K, thus increasing the adsorption capacity toward toluene. High ozone consumption could be associated to a high content of Lewis acid sites, since these could decompose ozone into atomic active oxygen species. Then, surface oxidation reactions could take part among adsorbed toluene at Brønsted acid sites and surface atomic oxygen species, reducing the amount of adsorbed toluene after the regenerative oxidation with ozone. Experimental results show that the presence of adsorbed oxidation by-products has a negative impact on the recovery of zeolite adsorption capacity. PMID:24794812

  6. Zeolite Crystal Growth

    NASA Astrophysics Data System (ADS)

    2002-12-01

    Zeolites are as hard as rocks but work like sponges. They have a rigid crystalline structure with a network of interconnected tunnels and cages, similar to honeycomb. These tunnels can store chemicals, like fuels, and then release them when the zeolites are heated. The Center for Advanced Microgravity Materials Processing (CAMMP) - one of 17 NASA sponsored Commercial Space Centers - is working to improve zeolite materials for storing hydrogen fuel. The center is also applying zeolite research to detergents, optical cables, gas and vapor detection for environmental monitoring and control, and chemical production techniques that significantly reduce hazardous by-products.

  7. Studies of anions sorption on natural zeolites.

    PubMed

    Barczyk, K; Mozgawa, W; Król, M

    2014-12-10

    This work presents results of FT-IR spectroscopic studies of anions-chromate, phosphate and arsenate - sorbed from aqueous solutions (different concentrations of anions) on zeolites. The sorption has been conducted on natural zeolites from different structural groups, i.e. chabazite, mordenite, ferrierite and clinoptilolite. The Na-forms of sorbents were exchanged with hexadecyltrimethylammonium cations (HDTMA(+)) and organo-zeolites were obtained. External cation exchange capacities (ECEC) of organo-zeolites were measured. Their values are 17mmol/100g for chabazite, 4mmol/100g for mordenite and ferrierite and 10mmol/100g for clinoptilolite. The used initial inputs of HDTMA correspond to 100% and 200% ECEC of the minerals. Organo-modificated sorbents were subsequently used for immobilization of mentioned anions. It was proven that aforementioned anions' sorption causes changes in IR spectra of the HDTMA-zeolites. These alterations are dependent on the kind of anions that were sorbed. In all cases, variations are due to bands corresponding to the characteristic Si-O(Si,Al) vibrations (occurring in alumino- and silicooxygen tetrahedra building spatial framework of zeolites). Alkylammonium surfactant vibrations have also been observed. Systematic changes in the spectra connected with the anion concentration in the initial solution have been revealed. The amounts of sorbed CrO4(2-), AsO4(3-) and PO4(3-) ions were calculated from the difference between their concentrations in solutions before (initial concentration) and after (equilibrium concentration) sorption experiments. Concentrations of anions were determined by spectrophotometric method. PMID:25002191

  8. Lithium modified zeolite synthesis for conversion of biodiesel-derived glycerol to polyglycerol

    SciTech Connect

    Ayoub, Muhammad; Abdullah, Ahmad Zuhairi; Inayat, Abrar

    2014-10-24

    Basic zeolite has received significant attention in the catalysis community. These zeolites modified with alkaline are the potential replacement for existing zeolite catalysts due to its unique features with added advantages. The present paper covers the preparation of lithium modified zeolite Y (Li-ZeY) and its activity for solvent free conversion of biodiesel-derived glycerol to polyglycerol via etherification process. The modified zeolite was well characterized by X-ray diffraction (XRD), Scanning Electron Microscope (SEM) and Nitrogen Adsorption. The SEM images showed that there was no change in morphology of modified zeolite structure after lithium modification. XRD patterns showed that the structure of zeolite was sustained after lithium modification. The surface properties of parent and modified zeolite was also observed N{sub 2} adsortion-desorption technique and found some changes in surface area and pore size. In addition, the basic strength of prepared materials was measured by Hammet indicators and found that basic strength of Li-ZeY was highly improved. This modified zeolite was found highly thermal stable and active heterogamous basic catalyst for conversion of solvent free glycerol to polyglycerol. This reaction was conducted at different temperatures and 260 °C was found most active temperature for this process for reaction time from 6 to 12 h over this basic catalyst in the absence of solvent.

  9. Lithium modified zeolite synthesis for conversion of biodiesel-derived glycerol to polyglycerol

    NASA Astrophysics Data System (ADS)

    Ayoub, Muhammad; Abdullah, Ahmad Zuhairi; Inayat, Abrar

    2014-10-01

    Basic zeolite has received significant attention in the catalysis community. These zeolites modified with alkaline are the potential replacement for existing zeolite catalysts due to its unique features with added advantages. The present paper covers the preparation of lithium modified zeolite Y (Li-ZeY) and its activity for solvent free conversion of biodiesel-derived glycerol to polyglycerol via etherification process. The modified zeolite was well characterized by X-ray diffraction (XRD), Scanning Electron Microscope (SEM) and Nitrogen Adsorption. The SEM images showed that there was no change in morphology of modified zeolite structure after lithium modification. XRD patterns showed that the structure of zeolite was sustained after lithium modification. The surface properties of parent and modified zeolite was also observed N2 adsortion-desorption technique and found some changes in surface area and pore size. In addition, the basic strength of prepared materials was measured by Hammet indicators and found that basic strength of Li-ZeY was highly improved. This modified zeolite was found highly thermal stable and active heterogamous basic catalyst for conversion of solvent free glycerol to polyglycerol. This reaction was conducted at different temperatures and 260 °C was found most active temperature for this process for reaction time from 6 to 12 h over this basic catalyst in the absence of solvent.

  10. Diagram of Zeolite Crystals

    NASA Technical Reports Server (NTRS)

    2003-01-01

    The Center for Advanced Microgravity Materials Processing (CAMMP) in Cambridge, MA, a NASA-sponsored Commercial Space Center, is working to improve zeolite materials for storing hydrogen fuel. CAMMP is also applying zeolites to detergents, optical cables, gas and vapor detection for environmental monitoring and control, and chemical production techniques that significantly reduce by-products that are hazardous to the environment. Depicted here is one of the many here complex geometric shapes which make them highly absorbent. Zeolite experiments have also been conducted aboard the International Space Station

  11. Zeolites: Exploring Molecular Channels

    SciTech Connect

    Arslan, Ilke; Derewinski, Mirek

    2015-05-22

    Synthetic zeolites contain microscopic channels, sort of like a sponge. They have many uses, such as helping laundry detergent lather, absorbing liquid in kitty litter, and as catalysts to produce fuel. Of the hundreds of types of zeolites, only about 15 are used for catalysis. PNNL catalysis scientists Ilke Arslan and Mirek Derewinksi are studying these zeolites to understand what make them special. By exploring the mystery of these microscopic channels, their fundamental findings will help design better catalysts for applications such as biofuel production.

  12. Regenerative Cu/La zeolite supported desulfurizing sorbents

    NASA Technical Reports Server (NTRS)

    Voecks, Gerald E. (inventor); Sharma, Pramod K. (inventor)

    1991-01-01

    Efficient, regenerable sorbents for removal of H2S from fluid hydrocarbons such as diesel fuel at moderate condition comprise a porous, high surface area aluminosilicate support, suitably a synthetic zeolite, and most preferably a zeolite having a free lattice opening of at least 6 Angstroms containing from 0.1 to 0.5 moles of copper ions, lanthanum ions or their mixtures. The sorbent removes sulfur from the hydrocarbon fuel in high efficiency and can be repetitively regenerated without loss of activity.

  13. Study of zeolite influence on analytical characteristics of urea biosensor based on ion-selective field-effect transistors

    PubMed Central

    2014-01-01

    A possibility of the creation of potentiometric biosensor by adsorption of enzyme urease on zeolite was investigated. Several variants of zeolites (nano beta, calcinated nano beta, silicalite, and nano L) were chosen for experiments. The surface of pH-sensitive field-effect transistors was modified with particles of zeolites, and then the enzyme was adsorbed. As a control, we used the method of enzyme immobilization in glutaraldehyde vapour (without zeolites). It was shown that all used zeolites can serve as adsorbents (with different effectiveness). The biosensors obtained by urease adsorption on zeolites were characterized by good analytical parameters (signal reproducibility, linear range, detection limit and the minimal drift factor of a baseline). In this work, it was shown that modification of the surface of pH-sensitive field-effect transistors with zeolites can improve some characteristics of biosensors. PMID:24636423

  14. Composite zeolite membranes

    DOEpatents

    Nenoff, Tina M. (Albuquerque, NM); Thoma, Steven G. (Albuquerque, NM); Ashley, Carol S. (Albuquerque, NM); Reed, Scott T. (Albuquerque, NM)

    2002-01-01

    A new class of composite zeolite membranes and synthesis techniques therefor has been invented. These membranes are essentially defect-free, and exhibit large levels of transmembrane flux and of chemical and isotopic selectivity.

  15. ZEOLITE CHARACTERIZATION TESTING

    SciTech Connect

    Jacobs, W; Herbert Nigg, H

    2007-09-13

    The Savannah River Site isolates tritium from its process streams for eventual recycling. This is done by catalyzing the formation of tritiated water (from process streams) and then sorbing that water on a 3A zeolite (molsieve) bed. The tritium is recovered by regenerating the saturated bed into a Mg-based water cracking unit. The process described has been in use for about 15 years. Recently chloride stress corrosion cracking (SCC) was noted in the system piping. This has resulted in the need to replace the corroded piping and associated molecular sieve beds. The source of chlorine has been debated and one possible source is the zeolite itself. Since new materials are being purchased for recently fabricated beds, a more comprehensive analysis protocol for characterizing zeolite has been developed. Tests on archived samples indicate the potential for mobile chloride species to be generated in the zeolite beds.

  16. Structural Flexibilities and Gas Adsorption Properties of One-Dimensional Copper(II) Polymers with Paddle-Wheel Units by Modification of Benzoate Ligands.

    PubMed

    Takahashi, Kiyonori; Hoshino, Norihisa; Takeda, Takashi; Noro, Shin-Ichiro; Nakamura, Takayoshi; Takeda, Sadamu; Akutagawa, Tomoyuki

    2015-10-01

    CO2 and N2 gas adsorption/desorption properties of one-dimensional copper(II) polymers with paddle-wheel units [Cu(II)2(p-XBA)4(pyrazine)]? were successfully controlled through the tuning of interchain interactions by modification of para-substituent X groups on the benzoate (BA) ligands (X = Cl, Br, I, and OCH3). Although none of the four crystals had sufficient void space to integrate the crystallization solvents, gate-opening gas adsorption and desorption behaviors coupled with structural phase transitions were observed for CO2 (T = 195 K) and N2 (T = 77 K), with differences depending on the precise substituent. van der Waals interchain interactions, specifically ?···?, halogen···?, and C-H···? contacts, were dominant in forming the crystal lattice; their magnitude was associated with gate-opening pressure and hysteresis behaviors. Both the type and magnitude of the interactions were evaluated by Hirshfeld surface analysis, which indicated that structural flexibility decreased as larger halogen atoms were included. Overall, weak interchain interaction and structural flexibility generated new void spaces to adsorb CO2 and N2 gases. PMID:26381225

  17. Zeolite with trimodal porosity by desilication of zeolite nanocrystals aggregate

    SciTech Connect

    Wang Yuxin; Liu Kaituo; Graduate School of the Chinese Academy of Sciences, Beijing 100049 ; He Tao; Wu Jinhu; Fang Yunming

    2012-10-15

    Zeolite with trimodal porosity can be synthesized by desilication of zeolite nanocrystal aggregate. In the desilication process, the originally existed intercrystalline mesopores of zeolite nanocrystal aggregate were enlarged into large mesopore, and the new small intracrystalline mesopore channel was created, thus the Zeolite with trimodal porosity was formed. The structure of resulted zeolite, both on aggregate and mesopore level can be fine tuned by the desilication degree. - Graphical abstract: The Si from the edges and boundary of nanocrystals was first removed resulted the surface roughness and enlarges of the originally existed intercrystalline mesopores. As the degree of alkali-treatment increasing, the Si species inside zeolite nanocrystals was also removed, leading to further enlarges the intercrystalline mesopores and the formation of small intracrystalline mesopores. In case the alkali-treatment is serve enough to completely dissolve the bridges between zeolite nanocrystals, zeolite nanocrystals were exfoliated from the aggregate. Highlights: Black-Right-Pointing-Pointer Zeolite with trimodal porosity by desilication of zeolite nanocrystals aggregate. Black-Right-Pointing-Pointer The original intercrystalline mesopores were enlarged into large mesopore. Black-Right-Pointing-Pointer The new intracrystalline mesopores were created as the inside Si extracted out. Black-Right-Pointing-Pointer The aggregate structure, crystallinity and acidity of parent zeolite remained. Black-Right-Pointing-Pointer Desilication is start on the edges then in the inner part of zeolite.

  18. Preparation of functionalized zeolitic frameworks

    DOEpatents

    Yaghi, Omar M.; Hayashi, Hideki; Banerjee, Rahul; Park, Kyo Sung; Wang, Bo; Cote, Adrien P.

    2014-08-19

    The disclosure provides zeolitic frameworks for gas separation, gas storage, catalysis and sensors. More particularly the disclosure provides zeolitic frameworks (ZIFs). The ZIF of the disclosure comprises any number of transition metals or a homogenous transition metal composition.

  19. Preparation of functionalized zeolitic frameworks

    DOEpatents

    Yaghi, Omar M; Furukawa, Hiroyasu; Wang, Bo

    2013-07-09

    The disclosure provides zeolitic frameworks for gas separation, gas storage, catalysis and sensors. More particularly the disclosure provides zeolitic frameworks (ZIFs). The ZIF of the disclosure comprises any number of transition metals or a homogenous transition metal composition.

  20. Preparation of functionalized zeolitic frameworks

    SciTech Connect

    Yaghi, Omar M; Hayashi, Hideki; Banerjee, Rahul; Park, Kyo Sung; Wang, Bo; Cote, Adrien P

    2012-11-20

    The disclosure provides zeolitic frameworks for gas separation, gas storage, catalysis and sensors. More particularly the disclosure provides zeolitic frameworks (ZIFs). The ZIF of the disclosure comprises any number of transition metals or a homogenous transition metal composition.

  1. Rapid synthesis of beta zeolites

    DOEpatents

    Fan, Wei; Chang, Chun -Chih; Dornath, Paul; Wang, Zhuopeng

    2015-08-18

    The invention provides methods for rapidly synthesizing heteroatom containing zeolites including Sn-Beta, Si-Beta, Ti-Beta, Zr-Beta and Fe-Beta. The methods for synthesizing heteroatom zeolites include using well-crystalline zeolite crystals as seeds and using a fluoride-free, caustic medium in a seeded dry-gel conversion method. The Beta zeolite catalysts made by the methods of the invention catalyze both isomerization and dehydration reactions.

  2. The removal of bacteria by modified natural zeolites.

    PubMed

    Milán, Z; de Las Pozas, C; Cruz, M; Borja, R; Sánchez, E; Ilangovan, K; Espinosa, Y; Luna, B

    2001-01-01

    The removal effect of natural and modified zeolites containing different heavy metals (Ni2+, Zn2+, Fe3+ and Cu2+) on pure cultures of Escherichia coli and Staphylococcus aureus in a solid medium was evaluated in this work. These experiments were carried out in a continuous mode treating municipal wastewater. Faecal coliform species and Pseudomonas aeruginosa were identified. The rate constants of heavy metal lixiviation were determined using a first order kinetic model. The removal effect of modified natural zeolites in both a solid medium and in continuous mode showed an increased elimination of the bacterial population. The results established a decreasing order of the removal effect as follows: Cu2+ > Fe3+ > Zn2+ > Ni2+. The best performance of columns was obtained for inlet bacterial concentrations below 10(6) cells/100 ml. Most of the identified bacterial species were affected by copper modified zeolites, although Serratia marcescens presented the highest sensitivity and Klebsiella pneumoniae the greatest resistance. PMID:11501306

  3. Dehydration of methyl {alpha}-hydroxyisobutyrate catalyzed by zeolites

    SciTech Connect

    Balkus, K.J. Jr.; Khanmamedova, A.K.

    1995-01-01

    The catalytic dehydration of methyl {alpha}-hyroxyisobutyrate over various zeolites in a flow reactor is described. Both NaY and NaX are effective catalysts for the selective conversion of MOB to methyl methacrylate. Modification with K{sup +} and Cs{sup +} enhances the activity and selectivity of NaY but renders NaX a less effective catalyst. Acidic zeolites (HY, Beta, GdNaX, SmNaY, fluorinated SmNaY) were shown to be quite active but poorly selective with catalyst deactivation resulting from coke formation. 26 refs., 7 figs., 2 tabs.

  4. Novel modified zeolites for energy-efficient hydrocarbon separations.

    SciTech Connect

    Arruebo, Manuel; Dong, Junhang; Anderson, Thomas (Burns and McDonnell, Kansas City, MO); Gu, Xuehong; Gray, Gary (Goodyear Chemical Company, Akron, OH); Bennett, Ron (Goodyear Chemical Company, Akron, OH); Nenoff, Tina Maria; Kartin, Mutlu; Johnson, Kaylynn (Goodyear Chemical Company, Akron, OH); Falconer, John; Noble, Richard

    2006-11-01

    We present synthesis, characterization and testing results of our applied research project, which focuses on the effects of surface and skeletal modification of zeolites for significant enhancements in current hydrocarbon (HC) separations. Zeolites are commonly used by the chemical and petroleum industries as catalysts and ion-exchangers. They have high potential for separations owing to their unique pore structures and adsorption properties and their thermal, mechanical and chemical properties. Because of zeolites separation properties, low cost, and robustness in industrial process, they are natural choice for use as industrial adsorbents. This is a multidisciplinary effort to research, design, develop, engineer, and test new and improved materials for the separation of branched vs. linear organic molecules found in commercially important HC streams via adsorption based separations. The focus of this project was the surface and framework modification of the commercially available zeolites, while tuning the adsorption properties and the selectivities of the bulk and membrane separations. In particular, we are interested with our partners at Goodyear Chemical, on how to apply the modified zeolites to feedstock isoprene purification. For the characterization and the property measurements of the new and improved materials powder X-ray diffraction (PXRD), Residual Gas Analyzer-Mass Spectroscopy (RGA-MS), Electron Microscopy (SEM/EDAX), temperature programmed desorption (TPD) and surface area techniques were utilized. In-situ carbonization of MFI zeolite membranes allowed for the maximum separation of isoprene from n-pentane, with a 4.1% enrichment of the binary stream with n-pentane. In four component streams, a modified MFI membrane had high selectivities for n-pentane and 1-3-pentadiene over isoprene but virtually no separation for the 2-methyl-2-butene/isoprene pair.

  5. Synthesis of new zeolite structures.

    PubMed

    Li, Jiyang; Corma, Avelino; Yu, Jihong

    2015-10-21

    The search for new zeolites is of continuous interest in the field of zeolite science because of their widespread application in catalysis and adsorption-separation. To this end, considerable efforts have been devoted to the preparation of new zeolites with novel porous architectures and compositions. Taking account of the key factors governing the formation of zeolites (e.g., guest species, framework elements, construction processes, etc.), several synthetic strategies have been developed recently. These allow the discovery of many new zeolites with unprecedented structural features, such as hierarchical pores, odd-ring numbers (11-, 15-rings), extra-large pores (16-, 18-, 20-, 28-, and 30-rings), chiral pores, and extremely complex framework topologies, etc. In this review, we will present the advances in the synthesis of new zeolite structures in the last decade, which are achieved by utilization of the synthetic strategies based on pre-designed structure-directing agents, heteroatom substitution, and topotactic transformations. PMID:25740693

  6. Zeolite crystal growth in space

    NASA Technical Reports Server (NTRS)

    Sacco, Albert, Jr.; Thompson, Robert W.; Dixon, Anthony G.

    1991-01-01

    The growth of large, uniform zeolite crystals in high yield in space can have a major impact on the chemical process industry. Large zeolite crystals will be used to improve basic understanding of adsorption and catalytic mechanisms, and to make zeolite membranes. To grow large zeolites in microgravity, it is necessary to control the nucleation event and fluid motion, and to enhance nutrient transfer. Data is presented that suggests nucleation can be controlled using chemical compounds (e.g., Triethanolamine, for zeolite A), while not adversely effecting growth rate. A three-zone furnace has been designed to perform multiple syntheses concurrently. The operating range of the furnace is 295 K to 473 K. Teflon-lined autoclaves (10 ml liquid volume) have been designed to minimize contamination, reduce wall nucleation, and control mixing of pre-gel solutions on orbit. Zeolite synthesis experiments will be performed on USML-1 in 1992.

  7. Effect of zeolite on toxicity of ammonia in freshwater sediments: Implications for toxicity identification evaluation procedures

    SciTech Connect

    Besser, J.M.; Ingersoll, C.G.; Leonard, E.N.; Mount, D.R.

    1998-11-01

    Techniques for reducing ammonia toxicity in freshwater sediments were investigated as part of a project to develop toxicity identification and evaluation (TIE) procedures for whole sediments. Although ammonia is a natural constituent of freshwater sediments, pollution can lead to ammonia concentrations that are toxic to benthic invertebrates, and ammonia can also contribute to the toxicity of sediments that contain more persistent contaminants. The authors investigated the use of amendments of a natural zeolite mineral, clinoptilolite, to reduce concentrations of ammonia in sediment pore water. Zeolites have been widely used for removal of ammonia in water treatment and in aqueous TIE procedures. The addition of granulated zeolite to ammonia-spiked sediments reduced pore-water ammonia concentrations and reduced ammonia toxicity to invertebrates. Amendments of 20% zeolite (v/v) reduced ammonia concentrations in pore water by {ge}70% in spiked sediments with ammonia concentrations typical of contaminated freshwater sediments. Zeolite amendments reduced toxicity of ammonia-spiked sediments to three taxa of benthic invertebrates (Hyalella azteca, Lumbriculus variegatus, and Chironomus tentans), despite their widely differing sensitivity to ammonia toxicity. In contrast, zeolite amendments did not reduce acute toxicity of sediments containing high concentrations of cadmium or copper or reduce concentrations of these metals in pore waters. These studies suggest that zeolite amendments, used in conjunction with toxicity tests with sensitive taxa such as H. azteca, may be an effective technique for selective reduction of ammonia toxicity in freshwater sediments.

  8. Effect of zeolite on toxicity of ammonia in freshwater sediments: Implications for toxicity identification evaluation procedures

    USGS Publications Warehouse

    Besser, J.M.; Ingersoll, C.G.; Leonard, E.N.; Mount, D.R.

    1998-01-01

    Techniques for reducing ammonia toxicity in freshwater sediments were investigated as part of a project to develop toxicity identification and evaluation (TIE) procedures for whole sediments. Although ammonia is a natural constituent of freshwater sediments, pollution can lead to ammonia concentrations that are toxic to benthic invertebrates, and ammonia can also contribute to the toxicity of sediments that contain more persistent contaminants. We investigated the use of amendments of a natural zeolite mineral, clinoptilolite, to reduce concentrations of ammonia in sediment pore water. Zeolites have been widely used for removal of ammonia in water treatment and in aqueous TIE procedures. The addition of granulated zeolite to ammonia-spiked sediments reduced pore-water ammonia concentrations and reduced ammonia toxicity to invertebrates. Amendments of 20% zeolite (v/v) reduced ammonia concentrations in pore water by ???70% in spiked sediments with ammonia concentrations typical of contaminated freshwater sediments. Zeolite amendments reduced toxicity of ammonia-spiked sediments to three taxa of benthic invertebrates (Hyalella azteca, Lumbriculus variegatus, and Chironomus tentans), despite their widely differing sensitivity to ammonia toxicity. In contrast, zeolite amendments did not reduce acute toxicity of sediments containing high concentrations of cadmium or copper or reduce concentrations of these metals in pore waters. These studies suggest that zeolite amendments, used in conjunction with toxicity tests with sensitive taxa such as H. azteca, may be an effective technique for selective reduction of ammonia toxicity in freshwater sediments.

  9. Synthesis and characterization of isostructural cadmium zeolitic imidazolate frameworks via solvent-assisted linker exchange

    E-print Network

    techniques for ZIFs will significantly facilitate the quest to obtain interesting and useful ZIF compounds, including compounds that cannot be synthesized directly. Introduction Zeolitic imidazolate frameworks (ZIFs furthermore, lithium­boron and copper­boron-based imidazo- late frameworks (BIFs) have also been synthesized

  10. Luminescent host–guest materials of electrostatically adsorbed Eu{sup 3+}(tta){sub 3}-tpyIL on zeolite L crystals

    SciTech Connect

    Li, Peng; Wang, Dongyue; Liang, Dong; Zhang, Li; Zhang, Shuming; Wang, Yige

    2014-07-01

    Graphical abstract: Luminescent host–guest materials exhibiting tunable emission colors by changing the excitation wavelength are obtained by surface modification of terbium(III) bipyridine-loaded zeolite L crystals with the ionic europium(III) complexes. - Highlights: • Luminescent ionic europium(III) complex was synthesized. • Outer surface of zeolite L was modified by electrostatic adsorption of the ionic complex. • Luminescent host–guest material with tunable emission color was obtained. - Abstract: The surface modification of zeolite L crystals with lanthanide complexes was achieved by electrostatic adsorption of ionic europium(III) complexes that are prepared by the reaction of tris(2-thenoyltrifluoroacetonate) europium(III) dehydrate with an organic salt containing terpyridine moieties on the negative charge-bearing surfaces of zeolite L crystals. Luminescent host–guest materials exhibiting tunable emission colors by changing the excitation wavelength are obtained by surface modification of terbium(III) bipyridine-loaded zeolite L crystals with the ionic europium(III) complexes.

  11. Utilizing copper(I) catalyzed azide-alkyne Huisgen 1,3-dipolar cycloaddition for the surface modification of colloidal particles with electroactive and emissive moieties

    NASA Astrophysics Data System (ADS)

    Rungta, Parul

    The development of charge-transporting and fluorescing colloidal particles that can be directly printed into electroluminescent devices may result in a broad impact on the use of electrical energy for illumination. The objective of this work was to design and synthesize electroactive & fluorescing colloidal particles; establish their optical, electronic, and thermodynamic properties; and transition them into a device format for potential applications. The original intended application of this work was to build "better" colloidally-based organic light emitting devices (OLEDs) by creating functional particles with superior electrical and optical performance relative to commercially available technologies, but through the course of the research, the particles that were developed were found to be better suited for medical applications. Nonetheless, the global objective envisioned at the onset of this research was consistent with its final outcomes. The research tasks pursued to accomplish this global objective included: (1) The design and synthesis of electroactive moieties and their conversion into organic light emitting devices; An electron-transporting monomer was synthesized that was structurally & energetically similar to the small molecule 2-biphenyl-4-yl-5-(4-tert-butylphenyl)-1,3,4-oxadiazole (tBu-PBD). The monomer was copolymerized with 2-(9H-carbazol-9-yl)ethyl 2-methylacrylate (CE) and the resulting copolymer was utilized in OLEDs which employed fluorescent coumarin 6 (C6) or phosphorescent tris(2-phenylpyridine)iridium(III) [Ir(ppy)3] emitters. The copolymer devices exhibited a mean luminance of ca. 400 and 3,552 cd/m2 with the C6 and Ir(ppy)3 emitters, that were stable with thermal aging at temperatures ranging from 23°C to 130°C. Comparable poly(9-vinyl-9H-carbazole)/tBu-PBD blend devices exhibited more pronounced variations in performance with thermal aging. (2) The surface-modification of colloids with electroactive & fluorescing moieties via "click" chemistry; Aqueous-phase 83 nm poly(propargyl acrylate) (PA) nanoparticles were surface-functionalized with sparingly water soluble fluorescent moieties through a copper(I)-catalyzed azide-alkyne cycloaddition (CuAAC) (i.e., "click" transformation) to produce fluoroprobes with a large Stokes shift. For moieties which could not achieve extensive surface coverage on the particles utilizing a standard click transformation procedure, the presence of beta-cyclodextrin (beta-CD) during the transformation enhanced the grafting density onto the particles. For an oxadiazole containing molecule (AO), an azide-modified coumarin 6 (AD1) and a polyethylene glycol modified naphthalimide-based emitter (AD2), respectively, an 84%, 17% and 5% increase in the grafting densities were observed, when the transformation was performed in the presence of beta-CD. In contrast, a carbazolyl-containing moiety (AC) exhibited a slight retardation in the final grafting density when beta-CD was employed. Photoluminescence studies indicated that AC & AO when attached to the particles form an exciplex. An efficient energy transfer from the exciplex to the surface attached AD2 resulted in a total Stokes shift of 180 nm for the modified particles. (3) The synthesis and characterization of near-infrared (NIR) emitting particles for potential applications in cancer therapy. PA particles were surface modified through the "click" transformation of an azide-terminated indocyanine green (azICG), an NIR emitter, and poly(ethylene glycol) (azPEG) chains of various molecular weights. The placement of azICG onto the surface of the particles allowed for the chromophores to complex with bovine serum albumin (BSA) when dispersed in PBS that resulted in an enhancement of the dye emission. In addition, the inclusion of azPEG with the chromophores onto the particle surface resulted in a synergistic nine-fold enhancement of the fluorescence intensity, with azPEGs of increasing molecular weight amplifying the response. Preliminary photodynamic therapy (PDT)

  12. Oxygen and hydrogen isotope geochemistry of zeolites

    NASA Technical Reports Server (NTRS)

    Karlsson, Haraldur R.; Clayton, Robert N.

    1990-01-01

    Oxygen and hydrogen isotope ratios for natural samples of the zeolites analcime, chabazite, clinoptilolite, laumontite, mordenite, and natrolite have been obtained. The zeolite samples were classified into sedimentary, hydrothermal, and igneous groups. The ratios for each species of zeolite are reported. The results are used to discuss the origin of channel water, the role of zeolites in water-rock interaction, and the possibility that a calibrated zeolite could be used as a low-temperature geothermometer.

  13. Enantioselective dehydration of butan-2-ol using zeolite Y modified with dithiane oxides

    SciTech Connect

    Feast, S.; Siddiqui, H.; Bethell, D.

    1997-04-15

    Modification of zeolite H-Y by dithiane oxides (2-R-1,3-dithiane 1-oxide; R = H, CH{sub 3}, C{sub 6}H{sub 5}) is shown to enhance significantly its activity for the acid catalyzed gas phase dehydration of butan-2-ol. The rate enhancement is observed for catalysts that are prepared by adding the dithiane oxide to the zeolite synthesis gel or by adsorption of the dithiane oxide onto commercial samples of zeolite H-Y. The origin of the rate enhancement is considered to result from a specific interaction between the dithiane oxide modifier with both the extra-framework and framework aluminum in the zeolite. Modification of zeolite H-Y with (R)-1,3-dithiane 1-oxide enhances the conversion of (S)-butan-2-ol compared to (R)-butan-2-ol in the temperature range 110-150{degrees}C when the two enantiomers are reacted separately. Modification with (S)-2-phenyl-1,3-dithiane 1-oxide gives a catalyst for which (R)-butan-2-ol is the most reactive of the two enantiomers. Reaction of racemic butan-2-ol over these chirally modified H-Y zeolites demonstrates that this modification procedure makes the zeolite enantiomerically discriminating and one enantiomer preferentially reacts, although both are present in the micropores under the reaction conditions. This effect is considered to be due to enantioselective rate enhancement, since, although the rate of dehydration of both enantiomers is enhanced in the chiral environment, the dehydration rate of one enantiomer is accelerated relative to the other. It is suggested that the effect is due to preferential adsorption at the chiral active site. 34 refs., 7 figs., 6 tabs.

  14. Study of ethylene adsorption on zeolite NaY modified with group I metal ions

    NASA Astrophysics Data System (ADS)

    Sue-aok, Niramai; Srithanratana, Tipaporn; Rangsriwatananon, Kunwadee; Hengrasmee, Sunantha

    2010-04-01

    The adsorption of ethylene by zeolite NaY and zeolite NaY modified by cation exchange with potassium, rubidium, and cesium ions was studied. Cation exchanges were carried out using KNO 3, RbNO 3, and CsNO 3 in the concentration ranges of 0.2-10 mM. XRD patterns and specific surface areas illustrated that modification of NaY zeolite by very dilute solutions containing K +, Rb + and Cs + did not lead to significant changes in the crystallinity. Analysis of metals content (ICP-OES) showed that Cs + can replace Na + better than Rb + and K +. Particle analysis indicated slight decreases in surface area but pore volumes and pore diameters remained unchanged. Ethylene adsorption isotherms indicated that Na-Y zeolite which was modified by 5.0 mM KNO 3, 0.5 mM RbNO 3 and 1.0 mM CsNO 3 could adsorb ethylene better than zeolite Na-Y. K-NaY zeolite adsorbed up to 102.45 cm 3/g ethylene, while Rb-NaY and Cs-NaY zeolites adsorbed up to 98.50 cm 3/g and 90.15 cm 3/g ethylene, respectively. Ethylene adsorption capacities depended on number of adsorption sites and surface interactions.

  15. Study on dioxygen reduction by mutational modifications of the hydrogen bond network leading from bulk water to the trinuclear copper center in bilirubin oxidase

    SciTech Connect

    Morishita, Hirotoshi; Kurita, Daisuke; Kataoka, Kunishige; Sakurai, Takeshi

    2014-07-18

    Highlights: • Proton transport pathway in bilirubin oxidase was mutated. • Two intermediates in the dioxygen reduction steps were trapped and characterized. • A specific glutamate for dioxygen reduction by multicopper oxidases was identified. - Abstract: The hydrogen bond network leading from bulk water to the trinuclear copper center in bilirubin oxidase is constructed with Glu463 and water molecules to transport protons for the four-electron reduction of dioxygen. Substitutions of Glu463 with Gln or Ala were attributed to virtually complete loss or significant reduction in enzymatic activities due to an inhibition of the proton transfer steps to dioxygen. The single turnover reaction of the Glu463Gln mutant afforded the highly magnetically interacted intermediate II (native intermediate) with a broad g = 1.96 electron paramagnetic resonance signal detectable at cryogenic temperatures. Reactions of the double mutants, Cys457Ser/Glu463Gln and Cys457Ser/Glu463Ala afforded the intermediate I (peroxide intermediate) because the type I copper center to donate the fourth electron to dioxygen was vacant in addition to the interference of proton transport due to the mutation at Glu463. The intermediate I gave no electron paramagnetic resonance signal, but the type II copper signal became detectable with the decay of the intermediate I. Structural and functional similarities between multicopper oxidases are discussed based on the present mutation at Glu463 in bilirubin oxidase.

  16. Multi-component lanthanide hybrids based on zeolite A/L and zeolite A/L-polymers for tunable luminescence.

    PubMed

    Chen, Lei; Yan, Bing

    2015-02-01

    Some multi-component hybrids based on zeolite L/A are prepared. Firstly, zeolite A/L is loaded with lanthanide complexes (Eu-DBM or Tb-AA (acetylacetone = AA, dibenzoylmethane = DBM)) into its channels. Secondly, 3-methacryloyloxypropyltrimethoxysilane (?-MPS) is used to covalently graft onto the surface of functionalized zeolite A/L (Si-[ZA/L?Eu-DBM(Tb-AA)]). Thirdly, lanthanide ions (Eu(3+)/Tb(3+)) are coordinated to the functionalized zeolite A/L and ligands (phen(1,10-phenanthroline) or bipy (2,2'-bipyridyl)) are introduced by a ship-in-bottle method. The inside-outside double modifications of ZA/L with lanthanide complexes afford the final hybrids and these are characterized by means of XRD, FT-IR, UV-vis DRS, SEM and luminescence spectroscopy, some of which display white or near-white light emission. Furthermore, selected above-mentioned hybrids are incorporated into PEMA/PMMA (poly ethyl methylacryate/poly methyl methacrylate) hosts to prepare luminescent polymer films. These results provide abundant data that these hybrid materials can be expected to have potential application in various practical fields. PMID:25411917

  17. Evaluation of operating characteristics for a chabazite zeolite system for treatment of process wastewater at Oak Ridge National Laboratory

    SciTech Connect

    Kent, T.E.; Perona, J.J.; Jennings, H.L.; Lucero, A.J.; Taylor, P.A.

    1998-02-01

    Laboratory and pilot-scale testing were performed for development and design of a chabazite zeolite ion-exchange system to replace existing treatment systems at the Process Waste Treatment Plant (PWTP) at Oak Ridge National Laboratory (ORNL). The process wastewater treatment systems at ORNL need upgrading to improve efficiency, reduce waste generation, and remove greater quantities of contaminants from the wastewater. Previous study indicated that replacement of the existing PWTP systems with an ion-exchange system using chabazite zeolite will satisfy these upgrade objectives. Pilot-scale testing of the zeolite system was performed using a commercially available ion-exchange system to evaluate physical operating characteristics and to validate smaller-scale column test results. Results of this test program indicate that (1) spent zeolite can be sluiced easily and completely from a commercially designed vessel, (2) clarification followed by granular anthracite prefilters is adequate pretreatment for the zeolite system, and (3) the length of the mass transfer zone was comparable with that obtained in smaller-scale column tests. Laboratory studies were performed to determine the loading capacity of the zeolite for selected heavy metals. These test results indicated fairly effective removal of silver, cadmium, copper, mercury, nickel, lead, and zinc from simple water solutions. Heavy-metals data collected during pilot-scale testing of actual wastewater indicated marginal removal of iron, copper, and zinc. Reduced effectiveness for other heavy metals during pilot testing can be attributed to the presence of interfering cations and the relatively short zeolite/wastewater contact time. Flocculating agents (polyelectrolytes) were tested for pretreatment of wastewater prior to the zeolite flow-through column system. Several commercially available polyelectrolytes were effective in flocculation and settling of suspended solids in process wastewater.

  18. Modification of the charge transport properties of the copper phthalocyanine/poly(vinyl alcohol) interface using cationic or anionic surfactant for field-effect transistor performance enhancement

    NASA Astrophysics Data System (ADS)

    Jastrombek, Diana; Nawaz, Ali; Koehler, Marlus; Meruvia, Michelle S.; Hümmelgen, Ivo A.

    2015-08-01

    We report on the performance enhancement of organic field-effect transistors prepared using cross-linked poly(vinyl alcohol) as gate dielectric and copper phthalocyanine as channel semiconductor through gate dielectric surface treatment. The gate dielectric surface was treated using either a cationic surfactant, hexadecyltrimethylammonium bromide (CTAB), or an anionic surfactant, sodium dodecyl sulfate (SDS). We determined the charge-carrier field-effect mobility (?? FET) in these transistors as a function of the effective channel thickness in the channel bottleneck, near to the transistor source. When compared to the untreated devices, in the devices treated with CTAB or SDS, the channel formation occurs at lower gate voltage and the carrier mobility in the thinnest channel region, corresponding to the immediate vicinity of the insulator/semiconductor interface, is significantly higher. The surfactant treatment leads to a tenfold increase in ? FET and significant enhancement in capacitance, on/off current ratio and transconductance of the transistor.

  19. Reclaiming silver from silver zeolite

    SciTech Connect

    Reimann, G.A.

    1991-10-01

    Silver zeolite is used to capture radioiodines from air cleaning systems in some nuclear facilities at the Idaho National Engineering Laboratory. It may become radioactively contaminated and/or poisoned by hydrocarbon vapors, which diminishes its capacity for iodine. Silver zeolite contains up to 38 wt% silver. A pyrometallurgical process was developed to reclaim the silver before disposing of the unserviceable zeolite as a radioactive waste. A flux was formulated to convert the refractory aluminosilicate zeolite structure into a low-melting fluid slag, with Na{sub 2}O added as NAOH instead of Na{sub 2}CO{sub 3} to avoid severe foaming due to CO{sub 2} evolution. A propane-fired furnace was built to smelt 45 kg charges at 1300C in a carbon-bonded silicon carbide crucible. A total of 218 kg (7000 tr oz) of silver was reclaimed from 1050 kg of unserviceable zeolite. Silver recoveries of 97% were achieved, and the radioisotopes were fixed as stable silicates in a vitreous slag that was disposed of as a low level waste. Recovered silver was refined using oxygen and cast into 100 tr oz bars assaying 99.8+% silver and showing no radioactive contamination.

  20. Constructing Hierarchical Porous Zeolites via Kinetic Regulation.

    PubMed

    Ding, Kunlun; Corma, Avelino; Maciá-Agulló, Juan Antonio; Hu, Jerry G; Krämer, Stephan; Stair, Peter C; Stucky, Galen D

    2015-09-01

    Zeolites are crystalline inorganic solids with microporous structures, having widespread applications in the fields of catalysis, separation, adsorption, microelectronics, and medical diagnosis. A major drawback of zeolites is the mass transfer limitation due to the small size of the micropores (less than 1 nm). Numerous efforts have been dedicated to integrating mesopores with the microporous zeolite structures by using templating and/or destructive approaches. Here we provide a new strategy for hierarchical pore size zeolite synthesis, without using supramolecular or hard templates. The branching epitaxial growth behavior, as a result of aluminum-zoning, contributes to the formation of the hierarchical porous zeolite structures. PMID:26322625

  1. Liquid-phase benzene oxidation to phenol with molecular oxygen catalyzed by Cu-zeolites

    SciTech Connect

    Ohtani, Tsuyoshi; Nishiyama, Satoru; Tsuruya, Shigeru

    1995-08-01

    The oxidation of benzene to form phenol using cuprous chloride as a catalyst has been reported by Sasaki and his co-workers, who used reaction system oxygen molecules as the oxidant. Takehira and his co-workers have studied benzene oxidation with molecular oxygen catalyzed by Cu(II) salts in the presence of ascorbic acid. Cu ion-exchanged zeolites have been reported to be useful as catalysts for the gas-phase oxidation of some organic materials, and copper ions in zeolites have been indicated to have redox properties according to physicochemical measurements. Armed with this knowledge, the authors have tried the liquid-phase oxidation of benzene with molecular oxygen under atmospheric pressure at room temperature using Cu ion-exchanged zeolite catalysts in the presence of ascorbic acid as a reducing reagent for Cu ions. The catalytic behavior of the Cu zeolites for the benzene oxidation was compared with that of nonanchored cupric and cuprous chloride catalysts. Also, some Cu catalysts impregnated on some amorphous oxide supports, in addition to the zeolites, were tested as catalysts for benzene oxidation with molecular oxygen. 13 refs., 5 figs., 3 tabs.

  2. Zeolite-like liquid crystals

    NASA Astrophysics Data System (ADS)

    Poppe, Silvio; Lehmann, Anne; Scholte, Alexander; Prehm, Marko; Zeng, Xiangbing; Ungar, Goran; Tschierske, Carsten

    2015-10-01

    Zeolites represent inorganic solid-state materials with porous structures of fascinating complexity. Recently, significant progress was made by reticular synthesis of related organic solid-state materials, such as metal-organic or covalent organic frameworks. Herein we go a step further and report the first example of a fluid honeycomb mimicking a zeolitic framework. In this unique self-assembled liquid crystalline structure, transverse-lying ?-conjugated rod-like molecules form pentagonal channels, encircling larger octagonal channels, a structural motif also found in some zeolites. Additional bundles of coaxial molecules penetrate the centres of the larger channels, unreachable by chains attached to the honeycomb framework. This creates a unique fluid hybrid structure combining positive and negative anisotropies, providing the potential for tuning the directionality of anisotropic optical, electrical and magnetic properties. This work also demonstrates a new approach to complex soft-matter self-assembly, by using frustration between space filling and the entropic penalty of chain extension.

  3. Modifications on the hydrogen bond network by mutations of Escherichia coli copper efflux oxidase affect the process of proton transfer to dioxygen leading to alterations of enzymatic activities

    SciTech Connect

    Kajikawa, Takao; Kataoka, Kunishige; Sakurai, Takeshi

    2012-05-25

    Highlights: Black-Right-Pointing-Pointer Proton transfer pathway to dioxygen in CueO was identified. Black-Right-Pointing-Pointer Glu506 is the key amino acid to transport proton. Black-Right-Pointing-Pointer The Ala mutation at Glu506 formed a compensatory proton transfer pathway. Black-Right-Pointing-Pointer The Ile mutation at Glu506 shut down the hydrogen bond network. -- Abstract: CueO has a branched hydrogen bond network leading from the exterior of the protein molecule to the trinuclear copper center. This network transports protons in the four-electron reduction of dioxygen. We replaced the acidic Glu506 and Asp507 residues with the charged and uncharged amino acid residues. Peculiar changes in the enzyme activity of the mutants relative to the native enzyme indicate that an acidic amino acid residue at position 506 is essential for effective proton transport. The Ala mutation resulted in the formation of a compensatory hydrogen bond network with one or two extra water molecules. On the other hand, the Ile mutation resulted in the complete shutdown of the hydrogen bond network leading to loss of enzymatic activities of CueO. In contrast, the hydrogen bond network without the proton transport function was constructed by the Gln mutation. These results exerted on the hydrogen bond network in CueO are discussed in comparison with proton transfers in cytochrome oxidase.

  4. Enhanced selectivity of zeolites by controlled carbon deposition

    DOEpatents

    Nenoff, Tina M.; Thoma, Steven G.; Kartin, Mutlu

    2006-05-09

    A method for carbonizing a zeolite comprises depositing a carbon coating on the zeolite pores by flowing an inert carrier gas stream containing isoprene through a regenerated zeolite at elevated temperature. The carbonized zeolite is useful for the separation of light hydrocarbon mixtures due to size exclusion and the differential adsorption properties of the carbonized zeolite.

  5. 2.5 Zeolites 2.5.1 Introduction

    E-print Network

    58 2.5 Zeolites 2.5.1 Introduction Zeolites are a well-established technology used in a range of processes and industries. Zeolites are not new materials--they have been investigated for over two in agriculture (St. Cloud 2007, BRZ Zeolite 2007, Zeolite Australia 2007), horticulture (ZeoPro 2007), gas

  6. Synthesis and testing of nanosized zeolite Y

    NASA Astrophysics Data System (ADS)

    Karami, Davood

    This work focuses on the synthesis and testing of nanosized zeolite Y. The synthesis formulations of faujasite-type structure of zeolite Y prepared in nanosized form are described. The synthetic zeolite Y is the most widely employed for the preparation of fluid catalytic cracking (FCC) catalysts. The synthesis of zeolite Y is very complicated process. The mean particle size of zeolite Y is 1800 nm. The major challenge of this work involved reducing this average particle size to less than 500 nm. The preliminary experiments were conducted to obtain the pure zeolite Y using the soluble silicates as a silica source. This was achieved by applying the experimental design approach to study the effects of many parameters. The ageing time turned out to be the most significant variable affecting product purity. Based on the preliminary results, a detailed investigation was carried out to determine the effects of silica-alumina precursor preparations on zeolite Y synthesis. Aluminosilicate precursors were prepared by gelling and precipitation of soluble silicate. The as-prepared precursors were used for the hydrothermal synthesis of zeolite Y. The procedure of the precipitation of soluble silicate yielded pure zeolite Y at the conventional synthesis conditions. The extent of purity of zeolite Y depends on the surface areas of aluminosilicate precursors. A novel approach to zeolite Y synthesis was employed for the preparation of the pure nanosized zeolite Y. This was achieved by applying the method of impregnation of precipitated silica. This novel method of impregnation for zeolite Y preparation allows eliminating the vigorous agitation step required for the preparation of a homogeneous silica solution, thereby simplifying the synthesis of zeolite Y in one single vessel. In case of the synthesis of nanosized zeolite Y, the effect of varying the organic templates on the formation of nanosized particles of zeolite Y was investigated, while all other reaction parameters were kept constant. The extent to which the nanosized zeolite Y was formed depended on the types and amount of the organic templates as well as the ageing duration. The activity testing of four FCC catalysts prepared by using CREY (Calcined Rare Earth ion-exchanged) zeolites with different particle sizes was carried out in a fluidized bench-scale batch riser simulator reactor. The starting zeolites NaY of different particle sizes were subjected to two cycles of ion exchange treatment. The particle size of the supported zeolites was varied between 150 and 1800 nm. The preparation of FCC catalysts was conducted by mixing the CREY zeolite with silica-alumina matrix and silica sol binder. Each catalyst contained 25% zeolite. The results of catalytic cracking demonstrated the significant effect of size reduction of the starting zeolite Y on catalytic performance of FCC catalyst. Keywords. Zeolite NaY, Faujasite, Nanosized particles, Nanozeolite, Nanotechnology, Synthesis, Crystallization, Seeding, Ageing, Precipitated silica, Sylopol silica, Fumed silica, Silica sol, Soluble silicates, Alumina, SAR or SiO2/Al2O3 Ratios, Sodium hydroxide, Sodium aluminate, Organic templates, TMAOH, Surfactant (CTAB), Ammonium Sulfate, BET surface area, BJH Pore Size Distribution, Zetasizer Particle Size Distribution, Powder XRD, 27Al Solid-State NMR, Catalytic Impregnation, CREY Zeolite, Silica-Alumina Matrix, Ion Exchange, FCC Catalyst, Catalytic cracking, Riser SimulatorRTM, Steaming, Zeolite HY, Utrastable Zeolite Y (USY)

  7. The influence of using Jordanian natural zeolite on the adsorption, physical, and mechanical properties of geopolymers products.

    PubMed

    Yousef, Rushdi Ibrahim; El-Eswed, Bassam; Alshaaer, Mazen; Khalili, Fawwaz; Khoury, Hani

    2009-06-15

    Geopolymers consist of an amorphous, three-dimensional structure resulting from the polymerization of aluminosilicate monomers that result from dissolution of kaolin in an alkaline solution at temperatures around 80 degrees C. One potential use of geopolymers is as Portland cement replacement. It will be of great importance to provide a geopolymer with suitable mechanical properties for the purpose of water storage and high adsorption capacity towards pollutants. The aim of this work is to investigate the effect of using Jordanian zeolitic tuff as filler on the mechanical performance and on the adsorption capacity of the geopolymers products. Jordanian zeolitic tuff is inexpensive and is known to have high adsorption capacity. The results confirmed that this natural zeolitic tuff can be used as a filler of stable geopolymers with high mechanical properties and high adsorption capacity towards methylene blue and Cu(II) ions. The XRD measurements showed that the phillipsite peaks (major mineral constituent of Jordanian zeolite) were disappeared upon geopolymerization. The zeolite-based geopolymers revealed high compressive strength compared to reference geopolymers that employ sand as filler. Adsorption experiments showed that among different geopolymers prepared, the zeolite-based geopolymers have the highest adsorption capacity towards methylene blue and copper(II) ions. PMID:19036505

  8. UTILITY OF ZEOLITES IN HAZARDOUS METAL REMOVAL FROM WATER

    EPA Science Inventory

    Zeolites are well known for their ion exchange, adsorption and acid catalysis properties. Different inorganic pollutants have been removed from water at room temperature by using synthetic zeolites. Zeolite Faujasite Y has been used to remove inorganic pollutants including arseni...

  9. Hydrogen Selective Exfoliated Zeolite Membranes

    SciTech Connect

    Tsapatsis, Michael; Daoutidis, Prodromos; Elyassi, Bahman; Lima, Fernando; Iyer, Aparna; Agrawal, Kumar; Sabnis, Sanket

    2015-04-06

    The objective of this project was to develop and evaluate an innovative membrane technology at process conditions that would be representative of Integrated Gasification Combined Cycle (IGCC) advanced power generation with pre-combustion capture of carbon dioxide (CO2). This research focused on hydrogen (H2)-selective zeolite membranes that could be utilized to separate conditioned syngas into H2-rich and CO2-rich components. Both experiments and process design and optimization calculations were performed to evaluate the concept of ultra-thin membranes made from zeolites nanosheets. In this work, efforts in the laboratory were made to tackle two fundamental challenges in application of zeolite membranes in harsh industrial environments, namely, membrane thickness and membrane stability. Conventional zeolite membranes have thicknesses in the micron range, limiting their performance. In this research, we developed a method for fabrication of ultimately thin zeolite membranes based on zeolite nanosheets. A range of layered zeolites (MWW, RWR, NSI structure types) suitable for hydrogen separation was successfully exfoliated to their constituent nanosheets. Further, membranes were made from one of these zeolites, MWW, to demonstrate the potential of this group of materials. Moreover, long-term steam stability of these zeolites (up to 6 months) was investigated in high concentrations of steam (35 mol% and 95 mole%), high pressure (10 barg), and high temperatures (350 °C and 600 °C) relevant to conditions of water-gas-shift and steam methane reforming reactions. It was found that certain nanosheets are stable, and that stability depends on the concentration of structural defects. Additionally, models that represent a water-gas-shift (WGS) membrane reactor equipped with the zeolite membrane were developed for systems studies. These studies had the aim of analyzing the effect of the membrane reactor integration into IGCC plants in terms of performance and economic aspects of the plants. Specifically, simulation and design optimization studies were performed using the developed stand-alone membrane reactor models to identify the membrane selectivity and permeance characteristics necessary to achieve desired targets of CO2 capture and H2 recovery, as well as guide the selection of the optimal reactor design that minimizes the membrane cost as a function of its surface area required. The isothermal membrane reactor model was also integrated into IGCC system models using both the MATLAB and Aspen software platforms and techno-economic analyses of the integrated plants have been carried out to evaluate the feasibility of replacing current technologies for pre-combustion capture by the proposed novel approach in terms of satisfying stream constraints and achieving the DOE target goal of 90% CO2 capture. The results of the performed analyses based on present value of annuity calculations showed break even costs for the membrane reactor within the feasible range for membrane fabrication. However, the predicted membrane performance used in these simulations exceeded the performance achieved experimentally. Therefore, further work is required to improve membrane performance.

  10. Adsorption of unsaturated hydrocarbons on zeolites: the eects of the zeolite framework on adsorption

    E-print Network

    Truong, Thanh N.

    Adsorption of unsaturated hydrocarbons on zeolites: the eects of the zeolite framework industrially important reactions, namely the polymerization and hydrocarbon cracking processes [9 as a starting point for a more comprehensive study on hydrocarbon cracking and ethylene epoxidation reactions

  11. Phosphorus promotion and poisoning in zeolite-based materials: synthesis, characterisation and catalysis

    PubMed Central

    van der Bij, Hendrik E.

    2015-01-01

    Phosphorus and microporous aluminosilicates, better known as zeolites, have a unique but poorly understood relationship. For example, phosphatation of the industrially important zeolite H-ZSM-5 is a well-known, relatively inexpensive and seemingly straightforward post-synthetic modification applied by the chemical industry not only to alter its hydrothermal stability and acidity, but also to increase its selectivity towards light olefins in hydrocarbon catalysis. On the other hand, phosphorus poisoning of zeolite-based catalysts, which are used for removing nitrogen oxides from exhaust fuels, poses a problem for their use in diesel engine catalysts. Despite the wide impact of phosphorus–zeolite chemistry, the exact physicochemical processes that take place require a more profound understanding. This review article provides the reader with a comprehensive and state-of-the-art overview of the academic literature, from the first reports in the late 1970s until the most recent studies. In the first part an in-depth analysis is undertaken, which will reveal universal physicochemical and structural effects of phosphorus–zeolite chemistry on the framework structure, accessibility, and strength of acid sites. The second part discusses the hydrothermal stability of zeolites and clarifies the promotional role that phosphorus plays. The third part of the review paper links the structural and physicochemical effects of phosphorus on zeolite materials with their catalytic performance in a variety of catalytic processes, including alkylation of aromatics, catalytic cracking, methanol-to-hydrocarbon processing, dehydration of bioalcohol, and ammonia selective catalytic reduction (SCR) of NOx. Based on these insights, we discuss potential applications and important directions for further research. PMID:26051875

  12. Phosphorus promotion and poisoning in zeolite-based materials: synthesis, characterisation and catalysis.

    PubMed

    van der Bij, Hendrik E; Weckhuysen, Bert M

    2015-10-21

    Phosphorus and microporous aluminosilicates, better known as zeolites, have a unique but poorly understood relationship. For example, phosphatation of the industrially important zeolite H-ZSM-5 is a well-known, relatively inexpensive and seemingly straightforward post-synthetic modification applied by the chemical industry not only to alter its hydrothermal stability and acidity, but also to increase its selectivity towards light olefins in hydrocarbon catalysis. On the other hand, phosphorus poisoning of zeolite-based catalysts, which are used for removing nitrogen oxides from exhaust fuels, poses a problem for their use in diesel engine catalysts. Despite the wide impact of phosphorus-zeolite chemistry, the exact physicochemical processes that take place require a more profound understanding. This review article provides the reader with a comprehensive and state-of-the-art overview of the academic literature, from the first reports in the late 1970s until the most recent studies. In the first part an in-depth analysis is undertaken, which will reveal universal physicochemical and structural effects of phosphorus-zeolite chemistry on the framework structure, accessibility, and strength of acid sites. The second part discusses the hydrothermal stability of zeolites and clarifies the promotional role that phosphorus plays. The third part of the review paper links the structural and physicochemical effects of phosphorus on zeolite materials with their catalytic performance in a variety of catalytic processes, including alkylation of aromatics, catalytic cracking, methanol-to-hydrocarbon processing, dehydration of bioalcohol, and ammonia selective catalytic reduction (SCR) of NOx. Based on these insights, we discuss potential applications and important directions for further research. PMID:26051875

  13. Energy and materials flows in the copper industry

    SciTech Connect

    Gaines, L.L.

    1980-12-01

    The copper industry comprises both the primary copper industry, which produces 99.9%-pure copper from copper ore, and the secondary copper industry, which salvages and recycles copper-containing scrap metal to extract pure copper or copper alloys. The United States uses about 2 million tons of copper annually, 60% of it for electrical applications. Demand is expected to increase less than 4% annually for the next 20 years. The primary copper industry is concentrated in the Southwest; Arizona produced 66% of the 1979 total ore output. Primary production uses about 170 x 10/sup 12/ Btu total energy annually (about 100 x 10/sup 6/ Btu/ton pure copper produced from ore). Mining and milling use about 60% of the total consumption, because low-grade ore (0.6% copper) is now being mined. Most copper is extracted by smelting sulfide ores, with concomitant production of sulfur dioxide. Clean air regulations will require smelters to reduce sulfur emissions, necessitating smelting process modifications that could also save 20 x 10/sup 12/ Btu (10 x 10/sup 6/ Btu/ton of copper) in smelting energy. Energy use in secondary copper production averages 20 x 10/sup 6/ Btu/ton of copper. If all copper products were recycled, instead of the 30% now salvaged, the energy conservation potential would be about one-half the total energy consumption of the primary copper industry.

  14. Amine-functionalized, silver-exchanged zeolite NaY: Preparation, characterization and antibacterial activity

    NASA Astrophysics Data System (ADS)

    Hanim, Siti Aishah Mohd; Malek, Nik Ahmad Nizam Nik; Ibrahim, Zaharah

    2016-01-01

    Amine-functionalized, silver-exchanged zeolite NaY (ZSA) were prepared with three different concentrations of 3-aminopropyltriethoxysilane (APTES) (0.01, 0.20 and 0.40 M) and four different concentrations of silver ions (25%, 50%, 100% and 200% from zeolite cation exchange capacity (CEC)). The samples were characterized by Fourier transform infrared (FTIR) spectroscopy, X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), energy-dispersive X-ray (EDX), surface area analysis, thermogravimetric analysis (TGA) and zeta potential (ZP) analysis. The FTIR results indicated that the zeolite was functionalized by APTES and that the intensity of the peaks corresponding to APTES increased as the concentration of APTES used was increased. The antibacterial activities of the silver-exchanged zeolite NaY (ZS) and ZSA were studied against Escherichia coli ATCC11229 and Staphylococcus aureus ATCC6538 using the disc diffusion technique (DDT) and minimum inhibitory concentration (MIC). The antibacterial activity of ZSA increased with the increase in APTES on ZS, and E. coli was more susceptible towards the sample compared to S. aureus. The FESEM micrographs of the bacteria after contact with the ZSA suggested different mechanisms of bacterial death for these two bacteria due to exposure to the studied sample. The functionalization of ZS with APTES improved the antibacterial activity of the silver-zeolite, depending on the concentration of silver ions and APTES used during modification.

  15. [What a physician should know about zeolites].

    PubMed

    Borani?, M

    2000-01-01

    Zeolites are natural and synthetic hydrated crystalline aluminosilicates endowed with absorptive and ion exchange properties. They have found numerous and multifarous applications--in industry as catalysts and absorbents, in water sanitation for the removal of ammonia and heavy metals, in agriculture as fertilizers, and in animal husbandry as the absorbents of excreted material and as food additives. Medical applications have included the use in filtration systems for anesthesia or dialysis and as the contrast materials in NMR imaging. Recently, zeolite powders for external use have found application as deodorants, antimycotic agents and wound dressings. Peroral use of encapsulated zeolite powders enriched with vitamins, oligoelements or other ingredients has been claimed to exert beneficial medical effects. Ingestion of zeolites may be considered analogous to the clay eating (geophagia), considered in traditional medicine as a remedy for various illnesses. Being amphoteric, zeolites are partly soluble in acid or alkaline media, but within the physiological pH range the solubility is generally low. Minimal amounts of free aluminium or silicium from the ingested zeolites are resorbed from the gut. The bulk of ingested zeolite probably remains undissolved in the gut. In view of the ion exchange properties, zeolites may be expected to change the ionic content, pH and buffering capacity of the gastrointestinal secretions and to affect the transport through the intestinal epithelium. In addition, zeolites could affect the bacterial flora and the resorption of bacterial products, vitamins and oligoelements. The contact of zeolite particles with gastrointestinal mucosa may elicit the secretion of cytokines with local and systemic actions. Reactive silicium ions might react with biomolecules of the intestinal epithelium, and if resorbed, do so in other cells. Mutagenic and carcinogenic effects of zeolite particles have been described, resembling such effects of asbestos fibers. Thus, local and systemic effects of zeolites may be complex and interrelated, and an objective assessment requires appropriate experimental models. PMID:11291273

  16. Copper Coordination in Cu-SSZ-13 and Cu-SSZ-16 Investigated by Variable-Temperature XRD

    SciTech Connect

    Fickel, D.; Lobo, R

    2010-01-01

    Nitrogen oxides (NO{sub x}) are a major atmospheric pollutant produced through the combustion of fossil fuels in internal combustion engines. Copper-exchanged zeolites are promising as selective catalytic reduction catalysts for the direct conversion of NO into N{sub 2} and O{sub 2}, and recent reports have shown the enhanced performance of Cu-CHA catalysts over other zeolite frameworks in the NO decomposition of exhaust gas streams. In the present study, Rietveld refinement of variable-temperature XRD synchrotron data obtained for Cu-SSZ-13 and Cu-SSZ-16 is used to investigate the location of copper cations in the zeolite pores and the effect of temperature on these sites and on framework stability. The XRD patterns show that the thermal stability of SSZ-13 is increased significantly when copper is exchanged into the framework compared with the acid form of the zeolite, H-SSZ-13. Cu-SSZ-13 is also more thermally stable than Cu-SSZ-16. From the refined diffraction patterns, the atomic positions of atoms, copper locations and occupancies, and thermal displacement parameters were determined as a function of temperature for both zeolites. Copper is found in the cages coordinated to three oxygen atoms of the six-membered rings.

  17. Fiber-optic exhaust-gas sensor based on the fluorescence characteristics of Cu containing zeolites

    NASA Astrophysics Data System (ADS)

    Remillard, Jeffrey

    2000-03-01

    A single catalyst in the exhaust system can reduce the concentration of toxic gases emitted by automobiles if the engine is operated close to the stoichiometric air-fuel ratio. This is accomplished through the use of an electrochemical oxygen sensor in the exhaust stream. Near the stoichiometric point, this sensor produces a step-function response when the exhaust gas transitions from an oxygen-poor to an oxygen-rich condition. This talk describes a different kind of sensor based on the use of copper-containing zeolites that produces a proportional output. Zeolites are a class of aluminosilicate materials that have an open 3D structure containing channels and cavities. The Al sites are negatively charged and are generally compensated by cations present during formation of the zeolite. Our experiments use a zeolite designated Cu-ZSM-5, which has the protons originally present in the ZSM-5 material replaced with cupric (Cu^+2) ions. Exposure of this zeolite to a reducing gas results in the conversion of some cupric ions to cuprous (Cu^+1) ions. Subsequent exposure of the zeolite to an oxidizing gas reverses this reaction. The use of this material as a gas sensor is based on the observation that cuprous ions produce a green fluorescent emission when exposed to blue light, whereas no fluorescence is observed from cupric ions. Monitoring the fluorescence of Cu-ZSM-5 placed in a gas stream can thus provide information on the gas's reductant-to-oxidant ratio. We present the results of high temperature in-situ fluorescence spectra, intensity, and reponse-time measurements performed on samples of Cu-ZSM-5 exposed to various O_2-reductant combinations and also discuss data obtained from a single-fiber prototype sensor fabricated using a sol-gel processing technique.(J.T. Remillard et al.), Appl. Opt. 38 5306 (1999).

  18. Increased thermal conductivity monolithic zeolite structures

    DOEpatents

    Klett, James (Knoxville, TN); Klett, Lynn (Knoxville, TN); Kaufman, Jonathan (Leonardtown, MD)

    2008-11-25

    A monolith comprises a zeolite, a thermally conductive carbon, and a binder. The zeolite is included in the form of beads, pellets, powders and mixtures thereof. The thermally conductive carbon can be carbon nano-fibers, diamond or graphite which provide thermal conductivities in excess of about 100 W/mK to more than 1,000 W/mK. A method of preparing a zeolite monolith includes the steps of mixing a zeolite dispersion in an aqueous colloidal silica binder with a dispersion of carbon nano-fibers in water followed by dehydration and curing of the binder is given.

  19. Treating Coalbed Natural Gas Produced Water for Beneficial Use By MFI Zeolite Membranes

    SciTech Connect

    Robert Lee; Liangxiong Li

    2008-03-31

    Desalination of brines produced from oil and gas fields is an attractive option for providing potable water in arid regions. Recent field-testing of subsurface sequestration of carbon dioxide for climate management purposes provides new motivation for optimizing efficacy of oilfield brine desalination: as subsurface reservoirs become used for storing CO{sub 2}, the displaced brines must be managed somehow. However, oilfield brine desalination is not economical at this time because of high costs of synthesizing membranes and the need for sophisticated pretreatments to reduce initial high TDS and to prevent serious fouling of membranes. In addition to these barriers, oil/gas field brines typically contain high concentrations of multivalent counter cations (eg. Ca{sup 2+} and SO{sub 4}{sup 2-}) that can reduce efficacy of reverse osmosis (RO). Development of inorganic membranes with typical characteristics of high strength and stability provide a valuable option to clean produced water for beneficial uses. Zeolite membranes have a well-defined subnanometer pore structure and extreme chemical and mechanical stability, thus showing promising applicability in produced water purification. For example, the MFI-type zeolite membranes with uniform pore size of {approx}0.56 nm can separate ions from aqueous solution through a mechanism of size exclusion and electrostatic repulsion (Donnan exclusion). Such a combination allows zeolite membranes to be unique in separation of both organics and electrolytes from aqueous solutions by a reverse osmosis process, which is of great interest for difficult separations, such as oil-containing produced water purification. The objectives of the project 'Treating Coalbed Natural Gas Produced Water for Beneficial Use by MFI Zeolite Membranes' are: (1) to conduct extensive fundamental investigations and understand the mechanism of the RO process on zeolite membranes and factors determining the membrane performance, (2) to improve the membranes and optimize operating conditions to enhance water flux and ion rejection, and (3) to perform long-term RO operation on tubular membranes to study membrane stability and to collect experimental data necessary for reliable evaluations of technical and economic feasibilities. Our completed research has resulted in deep understanding of the ion and organic separation mechanism by zeolite membranes. A two-step hydrothermal crystallization process resulted in a highly efficient membrane with good reproducibility. The zeolite membranes synthesized therein has an overall surface area of {approx}0.3 m{sup 2}. Multichannel vessels were designed and machined for holding the tubular zeolite membrane for water purification. A zeolite membrane RO demonstration with zeolite membranes fabricated on commercial alpha-alumina support was established in the laboratory. Good test results were obtained for both actual produced water samples and simulated samples. An overall 96.9% ion rejection and 2.23 kg/m{sup 2}.h water flux was achieved in the demonstration. In addition, a post-synthesis modification method using Al{sup 3+}-oligomers was developed for repairing the undesirable nano-scale intercrystalline pores. Considerable enhancement in ion rejection was achieved. This new method of zeolite membrane modification is particularly useful for enhancing the efficiency of ion separation from aqueous solutions because the modification does not need high temperature operation and may be carried out online during the RO operation. A long-term separation test for actual CBM produced water has indicated that the zeolite membranes show excellent ion separation and extraordinary stability at high pressure and produced water environment.

  20. Zeolites Remove Sulfur From Fuels

    NASA Technical Reports Server (NTRS)

    Voecks, Gerald E.; Sharma, Pramod K.

    1991-01-01

    Zeolites remove substantial amounts of sulfur compounds from diesel fuel under relatively mild conditions - atmospheric pressure below 300 degrees C. Extracts up to 60 percent of sulfur content of high-sulfur fuel. Applicable to petroleum refineries, natural-gas processors, electric powerplants, and chemical-processing plants. Method simpler and uses considerably lower pressure than current industrial method, hydro-desulfurization. Yields cleaner emissions from combustion of petroleum fuels, and protects catalysts from poisoning by sulfur.

  1. Zeolite-like liquid crystals.

    PubMed

    Poppe, Silvio; Lehmann, Anne; Scholte, Alexander; Prehm, Marko; Zeng, Xiangbing; Ungar, Goran; Tschierske, Carsten

    2015-01-01

    Zeolites represent inorganic solid-state materials with porous structures of fascinating complexity. Recently, significant progress was made by reticular synthesis of related organic solid-state materials, such as metal-organic or covalent organic frameworks. Herein we go a step further and report the first example of a fluid honeycomb mimicking a zeolitic framework. In this unique self-assembled liquid crystalline structure, transverse-lying ?-conjugated rod-like molecules form pentagonal channels, encircling larger octagonal channels, a structural motif also found in some zeolites. Additional bundles of coaxial molecules penetrate the centres of the larger channels, unreachable by chains attached to the honeycomb framework. This creates a unique fluid hybrid structure combining positive and negative anisotropies, providing the potential for tuning the directionality of anisotropic optical, electrical and magnetic properties. This work also demonstrates a new approach to complex soft-matter self-assembly, by using frustration between space filling and the entropic penalty of chain extension. PMID:26486751

  2. Zeolite-like liquid crystals

    PubMed Central

    Poppe, Silvio; Lehmann, Anne; Scholte, Alexander; Prehm, Marko; Zeng, Xiangbing; Ungar, Goran; Tschierske, Carsten

    2015-01-01

    Zeolites represent inorganic solid-state materials with porous structures of fascinating complexity. Recently, significant progress was made by reticular synthesis of related organic solid-state materials, such as metal-organic or covalent organic frameworks. Herein we go a step further and report the first example of a fluid honeycomb mimicking a zeolitic framework. In this unique self-assembled liquid crystalline structure, transverse-lying ?-conjugated rod-like molecules form pentagonal channels, encircling larger octagonal channels, a structural motif also found in some zeolites. Additional bundles of coaxial molecules penetrate the centres of the larger channels, unreachable by chains attached to the honeycomb framework. This creates a unique fluid hybrid structure combining positive and negative anisotropies, providing the potential for tuning the directionality of anisotropic optical, electrical and magnetic properties. This work also demonstrates a new approach to complex soft-matter self-assembly, by using frustration between space filling and the entropic penalty of chain extension. PMID:26486751

  3. Dispersion strengthened copper

    DOEpatents

    Sheinberg, Haskell (Los Alamos, NM); Meek, Thomas T. (Knoxville, TN); Blake, Rodger D. (Santa Fe, NM)

    1990-01-01

    A composition of matter comprised of copper and particles which are dispersed throughout the copper, where the particles are comprised of copper oxide and copper having a coating of copper oxide, and a method for making this composition of matter.

  4. Dispersion strengthened copper

    DOEpatents

    Sheinberg, Haskell (Los Alamos, NM); Meek, Thomas T. (Knoxville, TN); Blake, Rodger D. (Santa Fe, NM)

    1989-01-01

    A composition of matter comprised of copper and particles which are dispersed throughout the copper, where the particles are comprised of copper oxide and copper having a coating of copper oxide, and a method for making this composition of matter.

  5. Copper Test

    MedlinePLUS

    ... contaminate the sample with an external source of copper. Talk to the health practitioner and/or the laboratory that will perform ... about necessary precautions. If a urine or blood copper test result is higher than expected, the health practitioner may have the test repeated with a ...

  6. Copper Metallochaperones

    PubMed Central

    Robinson, Nigel J.; Winge, Dennis R.

    2014-01-01

    The current state of knowledge on how copper metallochaperones support the maturation of cuproproteins is reviewed. Copper is needed within mitochondria to supply the CuA and intramembrane CuB sites of cytochrome oxidase, within the trans-Golgi network to supply secreted cuproproteins and within the cytosol to supply superoxide dismutase 1 (Sod1). Subpopulations of copper-zinc superoxide dismutase also localize to mitochondria, the secretory system, the nucleus and, in plants, the chloroplast, which also requires copper for plastocyanin. Prokaryotic cuproproteins are found in the cell membrane and in the periplasm of gram-negative bacteria. Cu(I) and Cu(II) form tight complexes with organic molecules and drive redox chemistry, which unrestrained would be destructive. Copper metallochaperones assist copper in reaching vital destinations without inflicting damage or becoming trapped in adventitious binding sites. Copper ions are specifically released from copper metallochaperones upon contact with their cognate cuproproteins and metal transfer is thought to proceed by ligand substitution. PMID:20205585

  7. UTILITY OF ZEOLITES IN ARSENIC REMOVAL FROM WATER

    EPA Science Inventory

    Zeolites are well known for their ion exchange and adsorption properties. So far the cation exchanger properties of zeolites have been extensively studied and utilized. The anion exchanger properties of zeolites are less studied. Zeolite Faujasite Y has been used to remove arseni...

  8. Durability of Hydrophilic and Antimicrobial Zeolite Coatings under Water Immersion

    E-print Network

    Chen, Wilfred

    Durability of Hydrophilic and Antimicrobial Zeolite Coatings under Water Immersion Cory O-exchanged zeolite A (Ag-ZA) coatings have been shown to have excellent hydrophilicity and are highly antimicrobial Keywords: zeolite coating, zeolite A, hydrophilic, antimicrobial, gravity Introduction Condensing heat

  9. Evaluation of zeolite-sand mixtures as reactive materials protecting groundwater at waste disposal sites.

    PubMed

    Joanna, Fronczyk; Kazimierz, Garbulewski

    2013-09-01

    To recognize properties of a mixture of Vistula sand (medium sand acc. to USCS) with Slovak zeolite as reactive materials suitable for permeable reactive barriers proposed for protection of groundwater environment in vicinity of old landfills comprehensive laboratory investigations were performed. The present study investigates the removal of contaminants specific for landfill leachates onto zeolite-sand mixtures containing 20%, 50% and 80% of zeolite (ZS20, ZS50 and ZS80). Taking into account the results of batch tests it was concluded that the Langmuir isotherm best fitted the data. It was observed that the presence of ammonium, calcium and magnesium decreases the removal efficiency of copper by 32%. Column tests of contaminant migration through the attenuation zone of the reactive materials were interpreted using the software package CXTFIT, which solves a one-dimensional advection-dispersion equation. Column test results also indicate the strong influence of the presence of interfering substances on copper immobilisation; dynamic sorption capacities decrees twofold. Throughout the landfill leachate flow through ZS80 sample, a constant reduction of NH4+ (at 100%), K+ (at 93%) and Fe(total) (at an average of 86%) were observed. There was no reduction in chemical oxygen demand and biochemical oxygen demand. PMID:24520718

  10. SEQUESTERING MANURE N WITH SYNTHETIC ZEOLITES

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Natural zeolites have a long and successful history of agricultural use in Japan and more recently in the U.S. However the price (often > $US500 Mg -1) limits their use in agriculture. Zeolites can be synthesized from fly ash by reaction with sodium hydroxide solutions and low temperature. The proje...

  11. Visible emission from Ag+ exchanged SOD zeolites

    NASA Astrophysics Data System (ADS)

    Lin, H.; Imakita, K.; Fujii, M.; Prokof'ev, V. Yu.; Gordina, N. E.; Saïd, B.; Galarneau, A.

    2015-09-01

    Broad visible emissions dominant at green or red have been observed for the thermally-treated Ag+ exchanged SOD zeolites, determined by the Ag+ loading contents and the excitation wavelengths. Contrary to the notable reversible green/red dominant emission evolution in the Ag+ exchanged LTA zeolites upon hydration/dehydration in air (or water vapor)/vacuum, emission spectra of the Ag+ exchanged SOD zeolites are insensitive to the environmental change. This is most probably due to the difficult H2O permeation in SOD zeolites in comparison with LTA zeolites. By combining the environment dependent emission spectra of the Ag+ exchanged LTA and SOD zeolites, we proposed the following emission mechanisms for Ag+ exchanged LTA and SOD zeolites: the green emission is due to the transition from ligand-to-metal (framework O2- --> Ag+) charge transfer state to the ground state and the red emission is due to the transition from the metal-metal (Ag+-Ag+) charge transfer state to the ground state. The insensitive environment dependent emission characteristics of Ag+ exchanged SOD zeolites may have potential applications as robust phosphors.

  12. Visible emission from Ag(+) exchanged SOD zeolites.

    PubMed

    Lin, H; Imakita, K; Fujii, M; Prokof'ev, V Yu; Gordina, N E; Saïd, B; Galarneau, A

    2015-10-14

    Broad visible emissions dominant at green or red have been observed for the thermally-treated Ag(+) exchanged SOD zeolites, determined by the Ag(+) loading contents and the excitation wavelengths. Contrary to the notable reversible green/red dominant emission evolution in the Ag(+) exchanged LTA zeolites upon hydration/dehydration in air (or water vapor)/vacuum, emission spectra of the Ag(+) exchanged SOD zeolites are insensitive to the environmental change. This is most probably due to the difficult H2O permeation in SOD zeolites in comparison with LTA zeolites. By combining the environment dependent emission spectra of the Ag(+) exchanged LTA and SOD zeolites, we proposed the following emission mechanisms for Ag(+) exchanged LTA and SOD zeolites: the green emission is due to the transition from ligand-to-metal (framework O(2-)? Ag(+)) charge transfer state to the ground state and the red emission is due to the transition from the metal-metal (Ag(+)-Ag(+)) charge transfer state to the ground state. The insensitive environment dependent emission characteristics of Ag(+) exchanged SOD zeolites may have potential applications as robust phosphors. PMID:26349525

  13. The effect of pore dimension of zeolites on the separation of gas mixtures

    NASA Astrophysics Data System (ADS)

    Jee, Sang Eun

    We examined the effect of the pore dimension of zeolites on the separation of gas mixtures using atomistic simulation methods. We studied two categories of the zeolites with small pores: pore modified silicalite for H2/CH4 separation and small pore silica zeolites for CO2/CH4 separation. The effect of pore modification of silicalite on the H2/CH4 separation was examined. Under some degrees of surface modification, the CH4 flux was reduced much more than the H2 flux, resulting in high ideal selectivities. The use of small pore zeolites for CO2/CH4 separations was studied. In DDR, we showed that CO2 diffusion rates are only weakly affected by the presence of CH4, even though the latter molecules diffuse very slowly. Consequently, therefore, the permeance of CO 2 in the equimolar mixtures is similar to the permeance for pure CO 2, while the CH4 permeance in the mixture is greatly reduced relatively to the pure component permeance. The calculated CO2/CH 4 separation selectivities are higher than 100 for a wide range of feed pressure, indicating excellent separation capabilities of DDR based membranes. Inspired by the observation in DDR we also examined the separation capabilities of 10 additional pure silica small pore zeolites for CO2/CH 4 separations. From these considerations, we predict that SAS, MTF and RWR will exhibit high separation selectivities because of their very high adsorption selectivities for CO2 over CH4. CHA and IHW, which have similar pore structures to DDR, showed comparable separation selectivities to DDR because of large differences in the diffusion rates of CO2 and CH4.

  14. Flexibility mechanisms in ideal zeolite frameworks.

    PubMed

    Treacy, M M J; Dawson, C J; Kapko, V; Rivin, I

    2014-02-13

    Zeolites are microporous crystalline aluminosilicate materials whose atomic structures can be usefully modelled in purely mechanical terms as stress-free periodic trusses constructed from rigid corner-connected SiO4 and AlO4 tetrahedra. When modelled this way, all of the known synthesized zeolite frameworks exhibit a range of densities, known as the flexibility window, over which they satisfy the framework mechanical constraints. Within the flexibility window internal stresses are accommodated by force-free coordinated rotations of the tetrahedra about their apices (oxygen atoms). We use rigidity theory to explore the folding mechanisms within the flexibility window, and derive an expression for the configurational entropic density throughout the flexibility window. By comparison with the structures of pure silica zeolite materials, we conclude that configurational entropy associated with the flexibility modes is not a dominant thermodynamic term in most bulk zeolite crystals. Nevertheless, the presence of a flexibility window in an idealized hypothetical tetrahedral framework may be thermodynamically important at the nucleation stage of zeolite formation, suggesting that flexibility is a strong indicator that the topology is realizable as a zeolite. Only a small fraction of the vast number of hypothetical zeolites that are known exhibit flexibility. The absence of a flexibility window may explain why so few hypothetical frameworks are realized in nature. PMID:24379426

  15. Zeolites on Mars: Prospects for Remote Sensing

    NASA Technical Reports Server (NTRS)

    Gaffney, E. S.; Singer, R. B.; Kunkle, T. D.

    1985-01-01

    The Martian surface composition measured by Viking can be represented by several combinations of minerals incorporating major fractions of zeolites known to occur in altered mafic rocks and polar soils on Earth. The abundant occurrence of zeolites on Mars is consistent with what is known about both the physical and chemical environment of that planet. The laboratory reflectance spectra (0.65 to 2.55 microns) of a number of relatively pure zeolite minerals and some naturally occurring zeolite-clay soils were measured. All of the spectra measured are dominated by strong absorption near 1.4 and 1.9 microns and a steep reflectance drop longward of about 2.2 microns, all of which are due to abundant H2O. Weaker water overtone bands are also apparent, and in most cases there is spectral evidence for minor Fe(3+). In these features the zeolite spectra are similar to spectra of smectite clays which have abundant interlayer water. The most diagnostic difference between clay and zeolite spectra is the total absence in the zeolites of the weak structural OH absorption.

  16. Water nanodroplets confined in zeolite pores.

    PubMed

    Coudert, François-Xavier; Cailliez, Fabien; Vuilleumier, Rodolphe; Fuchs, Alain H; Boutin, Anne

    2009-01-01

    We provide a comprehensive depiction of the behaviour of a nanodroplet of approximately equal to 20 water molecules confined in the pores of a series of 3D-connected isostructural zeolites with varying acidity, by means of molecular simulations. Both grand canonical Monte Carlo simulations using classical interatomic forcefields and first-principles Car-Parrinello molecular dynamics were used in order to characterise the behaviour of confined water by computing a range of properties, from thermodynamic quantities to electronic properties such as dipole moment, including structural and dynamical information. From the thermodynamic point of view, we have identified the all-silica zeolite as hydrophobic, and the cationic zeolites as hydrophilic; the condensation transition in the first case was demonstrated to be of first order. Furthermore, in-depth analysis of the dynamical and electronic properties of water showed that water in the hydrophobic zeolite behaves as a nanodroplet trying to close its hydrogen-bond network onto itself, with a few short-lived dangling OH groups, while water in hydrophilic zeolites "opens up" to form weak hydrogen bonds with the zeolite oxygen atoms. Finally, the dipole moment of confined water is studied and the contributions of water self-polarisation and the zeolite electric field are discussed. PMID:19227366

  17. Structural diversity of lamellar zeolite Nu-6(1)--postsynthesis of delaminated analogues.

    PubMed

    Xu, Hao; Jia, Lili; Wu, Haihong; Yang, Boting; Wu, Peng

    2014-07-21

    Nu-6(1) zeolite, the lamellar precursor of NSI topology, was firstly synthesized with 4'4-bipyridine as the structure-directing agent (SDA) and then subjected to HCl-EtOH treatment for the purpose of structural modification. Interlayer deconstruction and reconstruction took place alternately in this acid treatment. An intermediate named ECNU-4 was separated at the initial stage of this continuous treatment process, which exhibited a special X-ray diffraction pattern without obvious reflection peaks at low angles. The zeolitic structure in the intralayer sheets was supposed to be well preserved in ECNU-4, whereas the interlayer structure became extremely disordered. The ECNU-4 intermediate showed structural diversity. It was converted into the reconstructed and interlayer expanded zeolite IEZ-NSI without an external silicon source by prolonging the HCl-EtOH treatment to 24 h. Moreover, with a partially delaminated structure, ECNU-4 was easily interlayer swollen at room temperature with cetyltrimethyl ammonium bromide in the presence of tetrapropyl ammonium hydroxide. The swollen material was further sonicated to yield a more deeply delaminated zeolite, Del-Nu-6. ECNU-4 and Del-Nu-6 differed in delamination degree, structural disordering and textural properties, especially surface area. PMID:24658572

  18. Interaction of surfactant-modified zeolites and phosphate accumulating bacteria.

    PubMed

    Hrenovic, J; Rozic, M; Sekovanic, L; Anic-Vucinic, A

    2008-08-15

    The aim of this study was to determine the interaction of surfactant-modified zeolites (SMZ) and orthophosphate (P)-accumulating bacteria in the process of P removal from wastewater. The SMZ were prepared from the natural zeolite (NZ) of size fractions <0.122 mm and 0.25-0.5 mm. The hexadecyltrimethylammonium (HDTMA) bromide was used to modify the NZ surface from partial monolayer to the bilayer coverage. The surface modification of NZ resulted in the change of zeta potential of particles from negative to positive and great enhancement of the P-adsorption capacity. Only in reactors containing <0.122 mm fraction of partial monolayer coverage of the SMZ, the P was efficiently removed from wastewater by combined adsorption onto the SMZ and bacterial uptake in the biomass. The SMZ with bilayer or patchy bilayer coverage showed the bactericidal effect. To enhance the P removal from wastewater in the aerated biological system, the SMZ can be used, but the special attention should be given to the configuration of sorbed HDTMA molecules and its potential desorption. PMID:18249067

  19. Complexation of porphyrins with nanoparticles of zeolite

    NASA Astrophysics Data System (ADS)

    Gyulkhandanyan, Anna G.; Zakoyan, Anna A.; Sargsyan, Hakob H.; Ghazaryan, Robert K.; Sheyranyan, Marina A.; Gyulkhandanyan, Grigor V.

    2015-06-01

    The binding of nanoparticles zeolite with a number of cationic porphyrins are studied. Previously, it was established that the main mechanism of binding the zeolite nanoparticles with cationic porphyrins is an ionic bond. Since binding of porphyrins as ligands to nanoparticles at the initial stage of interaction is determined by the Brownian motion of porphyrins, it is obvious that the interaction of porphyrins with nanoparticles may depend on the temperature. In the present paper by methods of absorption and fluorescence spectroscopy was studied the complexation of porphyrins with zeolite nanoparticles at different temperature conditions. It was established that there is a clear temperature dependence of the complexation of cationic metalloporphyrins with zeolite naonoparticles, and for correct determination of the percentage of binding must be strict thermostating of the experimental conditions.

  20. Selective anisotropic growth of zeolite crystals 

    E-print Network

    Desai, Tasha April

    2013-02-22

    -1 Selective Anisotropic Growth of Zeolite Crystals A Senior Honors Thesis by TASHA APRIL DESAI Submitted to the Office of Honors Programs & Academic Scholarships Texas A&M University in partial fulfillment of the requirements of the UNIVERSITY... UNDERGRADUATE RESEARCH FELLOWS Apri I 2003 Group: Engineering & Physics 3 Selective Anisotropic Growth of Zeolite Crystals A Senior Honors Thesis by TASFIA APRIL DESAI Submitted to the Office of Honors Programs k Academic Scholarships Texas A...

  1. An Effective Secondary Electron Emission Suppression Treatment For Copper MDC

    NASA Technical Reports Server (NTRS)

    Curren, Arthur N.; Long, Kenwyn J.; Jensen, Kenneth A.; Roman, Robert F.

    1993-01-01

    Untreated oxygen-free, high-conductivity (OFHC) copper, commonly used for MDC electrodes, exhibits relatively high secondary electron emission characteristics. This paper describes a specialized ion-bombardment procedure for texturing copper surfaces which sharply reduces the emission properties relative to untreated copper. The resulting surface is a particle-free, robust, uniformly highly-textured all-metal structure. The use of this process requires no modifications to copper machining, brazing, or other MDC normal fabrication procedures. The flight TWT for a planned NASA deep space probe, the Cassini Mission, will incorporate copper MDC electrodes treated with the method described here.

  2. Hierarchical ZSM-5 zeolites in shape-selective xylene isomerization: role of mesoporosity and acid site speciation.

    PubMed

    Fernandez, Christian; Stan, Irina; Gilson, Jean-Pierre; Thomas, Karine; Vicente, Aurélie; Bonilla, Adriana; Pérez-Ramírez, Javier

    2010-06-01

    The isomerization of o-xylene, a prototypical example of shape-selective catalysis by zeolites, was investigated on hierarchical porous ZSM-5. Extensive intracrystalline mesoporosity in ZSM-5 was introduced by controlled silicon leaching with NaOH. In addition to the development of secondary porosity, the treatment also induced substantial aluminum redistribution, increasing the density of Lewis acid sites located at the external surface of the crystals. However, the strength of the remaining Brønsted sites was not changed. The mesoporous zeolite displayed a higher o-xylene conversion than its parent, owing to the reduced diffusion limitations. However, the selectivity to p-xylene decreased, and fast deactivation due to coking occurred. This is mainly due to the deleterious effect of acidity at the substantially increased external surface and near the pore mouths. A consecutive mild HCl washing of the hierarchical zeolite proved effective to increase the p-xylene selectivity and reduce the deactivation rate. The HCl-washed hierarchical ZSM-5 displayed an approximately twofold increase in p-xylene yield compared to the purely microporous zeolite. The reaction was followed by operando infrared spectroscopy to simultaneously monitor the catalytic performance and the buildup of carbonaceous deposits on the surface. Our results show that the interplay between activity, selectivity, and stability in modified zeolites can be optimized by relatively simple post-synthesis treatments, such as base leaching (introduction of mesoporosity) and acid washing (surface acidity modification). PMID:20397162

  3. Zeolite-based SCR catalysts and their use in diesel engine emission treatment

    SciTech Connect

    Narula, Chaitanya K; Yang, Xiaofan

    2015-03-24

    A catalyst comprising a zeolite loaded with copper ions and at least one trivalent metal ion other than Al.sup.+3, wherein the catalyst decreases NO.sub.x emissions in diesel exhaust. The trivalent metal ions are selected from, for example, trivalent transition metal ions, trivalent main group metal ions, and/or trivalent lanthanide metal ions. In particular embodiments, the catalysts are selected from Cu--Fe-ZSM5, Cu--La-ZSM-5, Fe--Cu--La-ZSM5, Cu--Sc-ZSM-5, and Cu--In-ZSM5. The catalysts are placed on refractory support materials and incorporated into catalytic converters.

  4. Simultaneous determination of arsenic, cadmium, calcium, chromium, cobalt, copper, iron, lead, magnesium, manganese, molybdenum, nickel, selenium, and zinc in fertilizers by microwave acid digestion and inductively coupled plasma-optical emission spectrometry detection: single-laboratory validation of a modification and extension of AOAC 2006.03.

    PubMed

    Webb, Sharon; Bartos, James; Boles, Rhonda; Hasty, Elaine; Thuotte, Ethel; Thiex, Nancy J

    2014-01-01

    A single-laboratory validation study was conducted for the simultaneous determination of arsenic, cadmium, calcium, cobalt, copper, chromium, iron, lead, magnesium, manganese, molybdenum, nickel, selenium, and zinc in all major types of commercial fertilizer products by microwave digestion and inductively coupled plasma-optical emission spectroscopy analysis. This validation study proposes an extension and modification of AOAC 2006.03. The extension is the inclusion of calcium, copper, iron, magnesium, manganese, and zinc, and the modification is incorporation of hydrochloric acid in the digestion system. This dual acid digestion utilizes both hydrochloric and nitric acids in a 3 to 9 mL volume ratio/100 mL. In addition to 15 of the 30 original validation materials used in the 2006.03 collaborative study, National Institute of Standards and Technology Standard Reference Material 695 and Magruder 2009-06 were incorporated as accuracy materials. The main benefits of this proposed method are a significant increase in laboratory efficiency when compared to the use of both AOAC Methods 965.09 and 2006.03 to achieve the same objective and an enhanced recovery of several metals. PMID:25051614

  5. Thermodynamic modeling of natural zeolite stability

    SciTech Connect

    Chipera, S.J.; Bish, D.L.

    1997-06-01

    Zeolites occur in a variety of geologic environments and are used in numerous agricultural, commercial, and environmental applications. It is desirable to understand their stability both to predict future stability and to evaluate the geochemical conditions resulting in their formation. The use of estimated thermodynamic data for measured zeolite compositions allows thermodynamic modeling of stability relationships among zeolites in different geologic environments (diagenetic, saline and alkaline lakes, acid rock hydrothermal, basic rock, deep sea sediments). This modeling shows that the relative cation abundances in both the aqueous and solid phases, the aqueous silica activity, and temperature are important factors in determining the stable zeolite species. Siliceous zeolites (e.g., clinoptilolite, mordenite, erionite) present in saline and alkaline lakes or diagenetic deposits formed at elevated silica activities. Aluminous zeolites (e.g., natrolite, mesolite/scolecite, thomsonite) formed in basic rocks in association with reduced silica activities. Likewise, phillipsite formation is favored by reduced aqueous silica activities. The presence of erionite, chabazite, and phillipsite are indicative of environments with elevated potassium concentrations. Elevated temperature, calcic water conditions, and reduced silica activity help to enhance the laumontite and wairakite stability fields. Analcime stability increases with increased temperature and aqueous Na concentration, and/or with decreased silica activity.

  6. Effect of different glasses in glass bonded zeolite

    SciTech Connect

    Lewis, M.A.; Ackerman, J.P.; Verma, S.

    1995-05-01

    A mineral waste form has been developed for chloride waste salt generated during the pyrochemical treatment of spent nuclear fuel. The waste form consists of salt-occluded zeolite powders bound within a glass matrix. The zeolite contains the salt and immobilizes the fission products. The zeolite powders are hot pressed to form a mechanically stable, durable glass bonded zeolite. Further development of glass bonded zeolite as a waste form requires an understanding of the interaction between the glass and the zeolite. Properties of the glass that enhance binding and durability of the glass bonded zeolite need to be identified. Three types of glass, boroaluminosilicate, soda-lime silicate, and high silica glasses, have a range of properties and are now being investigated. Each glass was hot pressed by itself and with an equal amount of zeolite. MCC-1 leach tests were run on both. Soda-lime silicate and high silica glasses did not give a durable glass bonded zeolite. Boroaluminosilicate glasses rich in alkaline earths did bind the zeolite and gave a durable glass bonded zeolite. Scanning electron micrographs suggest that the boroaluminosilicate glasses wetted the zeolite powders better than the other glasses. Development of the glass bonded zeolite as a waste form for chloride waste salt is continuing.

  7. Salt-occluded zeolite waste forms: Crystal structures and transformability

    SciTech Connect

    Richardson, J.W. Jr.

    1996-12-31

    Neutron diffraction studies of salt-occluded zeolite and zeolite/glass composite samples, simulating nuclear waste forms loaded with fission products, have revealed complex structures, with cations assuming the dual roles of charge compensation and occlusion (cluster formation). These clusters roughly fill the 6--8 {angstrom} diameter pores of the zeolites. Samples are prepared by equilibrating zeolite-A with complex molten Li, K, Cs, Sr, Ba, Y chloride salts, with compositions representative of anticipated waste systems. Samples prepared using zeolite 4A (which contains exclusively sodium cations) as starting material are observed to transform to sodalite, a denser aluminosilicate framework structure, while those prepared using zeolite 5A (sodium and calcium ions) more readily retain the zeolite-A structure. Because the sodalite framework pores are much smaller than those of zeolite-A, clusters are smaller and more rigorously confined, with a correspondingly lower capacity for waste containment. Details of the sodalite structures resulting from transformation of zeolite-A depend upon the precise composition of the original mixture. The enhanced resistance of salt-occluded zeolites prepared from zeolite 5A to sodalite transformation is thought to be related to differences in the complex chloride clusters present in these zeolite mixtures. Data relating processing conditions to resulting zeolite composition and structure can be used in the selection of processing parameters which lead to optimal waste forms.

  8. The zeolite deposits of Greece

    USGS Publications Warehouse

    Stamatakis, M.G.; Hall, A.; Hein, J.R.

    1996-01-01

    Zeolites are present in altered pyroclastic rocks at many localities in Greece, and large deposits of potential economic interest are present in three areas: (1) the Evros region of the province of Thrace in the north-eastern part of the Greek mainland; (2) the islands of Kimolos and Poliegos in the western Aegean; and (3) the island of Samos in the eastern Aegean Sea. The deposits in Thrace are of Eocene-Oligocene age and are rich in heulandite and/or clinoptilolite. Those of Kimolos and Poliegos are mainly Quaternary and are rich in mordenite. Those of Samos are Miocene, and are rich in clinoptilolite and/or analcime. The deposits in Thrace are believed to have formed in an open hydrological system by the action of meteoric water, and those of the western Aegean islands in a similar way but under conditions of high heat flow, whereas the deposits in Samos were formed in a saline-alkaline lake.

  9. Probing zeolites by vibrational spectroscopies.

    PubMed

    Bordiga, Silvia; Lamberti, Carlo; Bonino, Francesca; Travert, Arnaud; Thibault-Starzyk, Frédéric

    2015-10-21

    This review addresses the most relevant aspects of vibrational spectroscopies (IR, Raman and INS) applied to zeolites and zeotype materials. Surface Brønsted and Lewis acidity and surface basicity are treated in detail. The role of probe molecules and the relevance of tuning both the proton affinity and the steric hindrance of the probe to fully understand and map the complex site population present inside microporous materials are critically discussed. A detailed description of the methods needed to precisely determine the IR absorption coefficients is given, making IR a quantitative technique. The thermodynamic parameters of the adsorption process that can be extracted from a variable-temperature IR study are described. Finally, cutting-edge space- and time-resolved experiments are reviewed. All aspects are discussed by reporting relevant examples. When available, the theoretical literature related to the reviewed experimental results is reported to support the interpretation of the vibrational spectra on an atomic level. PMID:26435467

  10. 11. EASTERN END OF ZEOLITE BUILDING. NOTE DIAL TO LEFT ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    11. EASTERN END OF ZEOLITE BUILDING. NOTE DIAL TO LEFT OF CLOCK GAUGING TOTAL ZEOLITE INFLUENT IN MILLIONS OF GALLONS PER DAY. - F. E. Weymouth Filtration Plant, 700 North Moreno Avenue, La Verne, Los Angeles County, CA

  11. Copper cyanide

    Integrated Risk Information System (IRIS)

    Copper cyanide ; CASRN 544 - 92 - 3 Human health assessment information on a chemical substance is included in the IRIS database only after a comprehensive review of toxicity data , as outlined in the IRIS assessment development process . Sections I ( Health Hazard Assessments for Noncarcinogenic Ef

  12. Cesium incorporation and diffusion in cancrinite, sodalite, zeolite, and allophane

    E-print Network

    Flury, Markus

    Cesium incorporation and diffusion in cancrinite, sodalite, zeolite, and allophane Jarai Mon of silicate minerals and precipitation of new aluminosilicate minerals. Cancrinite, sodalite, LTA zeolite in sodalite and cancrinite was far more difficult to replace than that in LTA zeolite or allophane. Most

  13. Zeolite-supported metal oxide sorbents for hot-gas desulfurization

    SciTech Connect

    Gasper-Galvin, L.D.; Atimtay, A.T.; Gupta, R.P.

    1998-10-01

    This paper describes the results of the development of supported mixed-metal oxide sorbents for hot-gas desulfurization capable of withstanding multiple sulfidation/regeneration cycles at 871 C (1600 F). The sorbents consisted of various combinations of copper, molybdenum, and/or manganese oxides supported on a high silica-containing zeolite. These sorbents were tested in a fixed-bed reactor with simulated coal gas at 205 kPa (15 psig). The combination of all three metal oxides displayed synergism in enhancing efficiency for H{sub 2}S removal and improved the crush strength on the pellets. Copper oxide was the most active component for reaction with H{sub 2}S, while molybdenum and manganese oxides appeared to act as catalysts/promoters. During multicycle testing, this ternary metal oxide sorbent retained its reactivity and mechanical strength.

  14. Synthesis of novel perfluoroalkylglucosides on zeolite and non-zeolite catalysts.

    PubMed

    Nowicki, Janusz; Mokrzycki, ?ukasz; Sulikowski, Bogdan

    2015-01-01

    Perfluoroalkylglucosides comprise a very important class of fluorine-containing surfactants. These compounds can be synthesized by using the Fisher reaction, starting directly from glucose and the required perfluoroalcohols. We wish to report on the use of zeolite catalysts of different structure and composition for the synthesis of perfluoroalkylglucosides when using glucose and 1-octafluoropentanol as substrates. Zeolites of different pore architecture have been chosen (ZSM-5, ZSM-12, MCM-22 and Beta). Zeolites were characterized by XRD, nitrogen sorption, scanning electron microscopy (SEM) and solid-state 27Al MAS NMR spectroscopy. The activity of the zeolite catalysts in the glycosidation reaction was studied in a batch reactor at 100 °C below atmospheric pressure. The performance of zeolites was compared to other catalysts, an ion-exchange resin (Purolite) and a montmorillonite-type layered aluminosilicate. The catalytic performance of zeolite Beta was the highest among the zeolites studied and the results were comparable to those obtained over Purolite and montmorillonite type catalysts. PMID:25856063

  15. 1. Introduction Copper, along with iron active sites dominate the field of

    E-print Network

    Chen, Peng

    heme ± iron centers).[8] The known copper proteins which are involved in dioxygen binding, activation-translational modification of a protein residue by the copper center. In the case of amine oxidase, this involves proteins include hemocya- nin, tyrosinase, and catechol oxidase.[5, 7] The binuclear copper centers

  16. Molecular recognition in cation-exchanged zeolites

    NASA Astrophysics Data System (ADS)

    Pidko, Evgeny A.; van Santen, Rutger A.

    The concepts of confinement- and molecular recognition-driven chemical reactivity of cation-exchanged zeolites is illustrated by our recent results from periodic and cluster density functional theory (DFT) calculations. The reactivity of alkali-earth- and alkaline-exchanged low-silica zeolites for selective photo-oxidation of alkenes with molecular oxygen and for N2O4 disproportionation is shown to be mainly due to the specific arrangement and the size of the cations in the zeolite cage. An attempt is made to separate the effects of basicity of the framework, the Lewis acidity of the extra-framework cations and the electrostatic field in the zeolite cage as well as its geometrical properties for the respective reactions. The importance of the favorable adsorption fashion of the reagents controlled by noncovalent interactions with the microporous matrix is shown. The role of the weak interactions with the zeolite walls and the factors, which determine the preference for a particular adsorption mode, are discussed by the example of light alkanes adsorption to Mg- and Ca-exchanged faujasites.

  17. Italian zeolitized rocks of technological interest

    NASA Astrophysics Data System (ADS)

    de'Gennaro, M.; Langella, A.

    1996-09-01

    Large areas of Italian territory are covered by thick and widespread deposits of zeolite-bearing volcaniclastic products. The main zeolites are phillipsite and chabazite spread over the whole peninsula, and clinoptilolite recorded only in Sardinia. A trachytic to phonolitic glassy precursor accounts for the formation of the former zeolites characterized by low Si/Al ratios (?3.00), while clinoptilolite is related to more acidic volcanism. The genesis of most of these zeolitized deposits is linked to pyroclastic flow emplacement mechanisms characterized by quite high temperatures and by the presence of abundant fluids. The main utilization of these materials has been and still is as dimension stones in the building industry. Currently, limited amounts are also employed in animal farming (dietary supplement, pet litter and manure deodorizer) and in agriculture as soil improvement and slow-release fertilizers. New fields of application have been proposed for these products on account of their easy availability, very low cost, their high-grade zeolites (50 70%), and good technological features such as high cation exchange capacities and adsorption properties.

  18. Zeolite-templated Pt/C electrocatalysts

    SciTech Connect

    Coker, Eric N.; Steen, William A.; Miller, James E.

    2008-06-16

    In an effort to reduce the amount of platinum required in low temperature fuel cells, we have prepared electrocatalysts of platinum nanoparticles-on-carbon through zeolite-templating methods. Several different zeolite structure-types, as well as clays and mesoporous silicas were investigated as hosts for the preparation of small Pt clusters through thermal decomposition of ion exchanged (NH{sub 3}){sub 4}Pt{sup 2+}. Several factors relating to cluster confinement and mobility influence cluster size, and clusters below 1 nm with narrow size distribution have been prepared. To enable electrochemical application, the pores of the Pt cluster-containing zeolite were filled with electrically conductive carbon via infiltration with carbon precursors, polymerization, and pyrolysis. The zeolite host was then removed by acid digestion, to leave a micro-/mesoporous Pt/C electrocatalyst possessing Pt clusters of controlled size. Preliminary electrochemical evaluation of these catalysts is reported. The energetics of thermal decomposition of (NH{sub 3}){sub 4}Pt{sup 2+} to form Pt clusters in zeolite X have been investigated through Differential Scanning Calorimetry, and apparent activation energies calculated. The relationship between (NH{sub 3}){sub 4}Pt{sup 2+} decomposition and conditions of calcination has been explored in an effort to better control Pt cluster sizes.

  19. Copper peroxide

    NASA Technical Reports Server (NTRS)

    Moser, L.

    1988-01-01

    A number of oxidizing agents, including chlorine, bromine, ozone and other peroxides, were allowed to act on copper solutions with the intention of forming copper peroxide. The only successful agent appears to be hydrogen peroxide. It must be used in a neutral 50 to 30 percent solution at a temperature near zero. Other methods described in the literature apparently do not work. The excess of hydrogen must be quickly sucked out of the brown precipitate, which it is best to wash with alcohol and ether. The product, crystalline under a microscope, can be analyzed only approximately. It approaches the formula CuO2H2O. In alkaline solution it appears to act catalytically in causing the decomposition of other peroxides, so that Na2O2 cannot be used to prepare it. On the addition of acids the H2O2 is regenerated. The dry substance decomposes much more slowly than the moist but is not very stable.

  20. COPPER AND BRAIN FUNCTION

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Increasing evidence shows that brain development and function are impaired when the brain is deprived of copper either through dietary copper deficiency or through genetic defects in copper transport. A number of copper-dependent enzymes whose activities are lowered by copper deprivation form the ba...

  1. Dispersion strengthened copper

    DOEpatents

    Sheinberg, H.; Meek, T.T.; Blake, R.D.

    1990-01-09

    A composition of matter is described which is comprised of copper and particles which are dispersed throughout the copper, where the particles are comprised of copper oxide and copper having a coating of copper oxide. A method for making this composition of matter is also described. This invention relates to the art of powder metallurgy and, more particularly, it relates to dispersion strengthened metals.

  2. Growth of zeolite crystals in the microgravity environment of space

    NASA Technical Reports Server (NTRS)

    Sacco, A., Jr.; Sand, L. B.; Collette, D.; Dieselman, K.; Crowley, J.; Feitelberg, A.

    1986-01-01

    Zeolites are hydrated, crystalline aluminosilicates with alkali and alkaling earth metals substituted into cation vacancies. Typically zeolite crystals are 3 to 8 microns. Larger cyrstals are desirable. Large zeolite crystals were produced (100 to 200 microns); however, they have taken restrictively long times to grow. It was proposed if the rate of nucleation or in some other way the number of nuclei can be lowered, fewer, larger crystals will be formed. The microgravity environment of space may provide an ideal condition to achieve rapid growth of large zeolite crystals. The objective of the project is to establish if large zeolite crystals can be formed rapidly in space.

  3. Zeolite, a versatile air pollutant adsorber. Technical bulletin (final)

    SciTech Connect

    Not Available

    1999-05-01

    The purpose of this document is to make people aware of zeolite, what it is, and what other used it has had. Zeolite is a relatively new medium for adsorption, but has a long history in other uses. Synthetic zeolite has an important role to play in controlling volatile organic compound (VOC) emissions. This document describes what synthetic zeolite is, and what it can do. Also shown are a number of other instances in which the unique properties of zeolite have been used to advantage.

  4. Hydrogen Purification Using Natural Zeolite Membranes

    NASA Technical Reports Server (NTRS)

    DelValle, William

    2003-01-01

    The School of Science at Universidad del Turabo (UT) have a long-lasting investigation plan to study the hydrogen cleaning and purification technologies. We proposed a research project for the synthesis, phase analysis and porosity characterization of zeolite based ceramic perm-selective membranes for hydrogen cleaning to support NASA's commitment to achieving a broad-based research capability focusing on aerospace-related issues. The present study will focus on technology transfer by utilizing inorganic membranes for production of ultra-clean hydrogen for application in combustion. We tested three different natural zeolite membranes (different particle size at different temperatures and time of exposure). Our results show that the membranes exposured at 900 C for 1Hr has the most higher permeation capacity, indicated that our zeolite membranes has the capacity to permeate hydrogen.

  5. Crystal engineering of zeolites with graphene

    NASA Astrophysics Data System (ADS)

    Gebhardt, Paul; Pattinson, Sebastian W.; Ren, Zhibin; Cooke, David J.; Elliott, James A.; Eder, Dominik

    2014-06-01

    Achieving control over the morphology of zeolite crystals at the nanoscale is crucial for enhancing their performance in diverse applications including catalysis, sensors and separation. The complexity and sensitivity of zeolite synthesis processes, however, often make such control both highly empirical and difficult to implement. We demonstrate that graphene can significantly alter the morphology of titanium silicalite (TS-1) particles, in particular being able to reduce their dimensions from several hundreds to less than 10 nm. Through electron microscopy and molecular mechanics simulations we propose a mechanism for this change based on the preferential interaction of specific TS-1 surfaces with benzyl-alcohol-mediated graphene. These findings suggest a facile new means of controlling the zeolite morphology and thereby also further demonstrate the potential of graphene in hybrid materials. Moreover, the generality of the mechanism points the way to a new avenue of research in using two-dimensional materials to engineer functional inorganic crystals.Achieving control over the morphology of zeolite crystals at the nanoscale is crucial for enhancing their performance in diverse applications including catalysis, sensors and separation. The complexity and sensitivity of zeolite synthesis processes, however, often make such control both highly empirical and difficult to implement. We demonstrate that graphene can significantly alter the morphology of titanium silicalite (TS-1) particles, in particular being able to reduce their dimensions from several hundreds to less than 10 nm. Through electron microscopy and molecular mechanics simulations we propose a mechanism for this change based on the preferential interaction of specific TS-1 surfaces with benzyl-alcohol-mediated graphene. These findings suggest a facile new means of controlling the zeolite morphology and thereby also further demonstrate the potential of graphene in hybrid materials. Moreover, the generality of the mechanism points the way to a new avenue of research in using two-dimensional materials to engineer functional inorganic crystals. Electronic supplementary information (ESI) available. See DOI: 10.1039/c4nr00320a

  6. Structure of nanochannel entrances in stopcock-functionalized zeolite?L composites.

    PubMed

    Tabacchi, Gloria; Fois, Ettore; Calzaferri, Gion

    2015-09-14

    Multifunctional hybrid materials are obtained by modifying zeolite?L (ZL) with stopcock molecules, consisting of a tail group that can enter the ZL nanochannels and a head group too large to pass the channel opening. However, to date no microscopic-level structural information on modified ZL materials has been reported. Herein we draw atomistic pictures of channel openings and stopcock-functionalized ZL based on first-principles calculations. We elucidate the interactions of the tail group with the inner surface of ZL channels and the space-filling properties of the stopcocks, revealing cork- or lid-sealing modes. Water is essential to obtain stable modifications. Al?OH groups are the preferred modification sites, bipodal modifications suffer from strain, and tripod binding is ruled out. Our results suggest the viability of recursive functionalization by cross-linking. PMID:26255642

  7. Fly ash zeolite catalyst support for Fischer-Tropsch synthesis

    NASA Astrophysics Data System (ADS)

    Campen, Adam

    This dissertation research aimed at evaluating a fly ash zeolite (FAZ) catalyst support for use in heterogeneous catalytic processes. Gas phase Fischer-Tropsch Synthesis (FTS) over a fixed-bed of the prepared catalyst/FAZ support was identified as an appropriate process for evaluation, by comparison with commercial catalyst supports (silica, alumina, and 13X). Fly ash, obtained from the Wabash River Generating Station, was first characterized using XRD, SEM/EDS, particle size, and nitrogen sorption techniques. Then, a parametric study of a two-step alkali fusion/hydrothermal treatment process for converting fly ash to zeolite frameworks was performed by varying the alkali fusion agent, agent:flyash ratio, fusion temperature, fused ash/water solution, aging time, and crystallization time. The optimal conditions for each were determined to be NaOH, 1.4 g NaOH: 1 g fly ash, 550 °C, 200 g/L, 12 hours, and 48 hours. This robust process was applied to the fly ash to obtain a faujasitic zeolite structure with increased crystallinity (40 %) and surface area (434 m2/g). Following the modification of fly ash to FAZ, ion exchange of H+ for Na+ and cobalt incipient wetness impregnation were used to prepare a FTS catalyst. FTS was performed on the catalysts at 250--300 °C, 300 psi, and with a syngas ratio H2:CO = 2. The HFAZ catalyst support loaded with 11 wt% cobalt resulted in a 75 % carbon selectivity for C5 -- C18 hydrocarbons, while methane and carbon dioxide were limited to 13 and 1 %, respectively. Catalyst characterization was performed by XRD, N2 sorption, TPR, and oxygen pulse titration to provide insight to the behavior of each catalyst. Overall, the HFAZ compared well with silica and 13X supports, and far exceeded the performance of the alumina support under the tested conditions. The successful completion of this research could add value to an underutilized waste product of coal combustion, in the form of catalyst supports in heterogeneous catalytic processes.

  8. Copper in diet

    MedlinePLUS

    Copper is an essential trace mineral present in all body tissues. ... Reference Intakes: Vitamin A, Vitamin K, Arsenic, Boron, Chromium, Copper, Iodine, Iron Manganese, Molybdenium, Nickel, Silicon, Vanadium, ...

  9. In situ DRIFTS-MS studies on the oxidation of adsorbed NH3 by NOx over a Cu-SSZ-13 zeolite

    SciTech Connect

    Zhu, Haiyang; Kwak, Ja Hun; Peden, Charles HF; Szanyi, Janos

    2013-04-30

    DRIFT spectroscopy combined with mass spectrometry was used to investigate the oxidation of adsorbed ammonia by NO2, NO+O2 and NO2+O2 on a copper ion exchanged SSZ 13 (Cu-SSZ-13) zeolite. Compared with both NO2 and NO, the adsorption of ammonia is much stronger on the Cu-SSZ-13 zeolite. Two adsorbed ammonia species were found over the Cu-SSZ-13 zeolite studied here; notably ammonia on Brönsted acid sites (proton) and ammonia on Lewis acid sites (copper ions). These adsorbed ammonia species present different activity profiles and selectivity to N2 during NH3 oxidation. The results obtained suggest that ammonia adsorbed onto copper ions in Cu-SSZ-13 are more active at low temperatures than proton-adsorbed NH3, and give rise to a higher selectivity to N2. The formation of N2O is associated primarily with the reaction of NOx with proton-adsorbed NH3 via the formation and subsequent thermal decomposition of NH4NO3. Financial support was provided by the US Department of Energy (DOE), Office of Energy Efficiency and Renewable Energy, Vehicle Technologies Program. Portions of this work were performed in the Environmental Molecular Sciences Laboratory (EMSL) at Pacific Northwest National Laboratory (PNNL). The EMSL is a national scientific user facility supported by the US DOE, Office of Biological and Environmental Research. PNNL is a multi-program national laboratory operated for the US DOE by Battelle.

  10. MCM-41 impregnated with A zeolite precursor: Synthesis, characterization and tetracycline antibiotics removal from aqueous solution

    PubMed Central

    Liu, Minmin; Hou, Li-an; Yu, Shuili; Xi, Beidou; Zhao, Ying; Xia, Xunfeng

    2013-01-01

    In this paper, the MCM-41 has been modified by impregnation with zeolite A to prepare a kind of new adsorbent. The adsorption of TC from aqueous solutions onto modified MCM-41 has been studied. It was discovered that the adsorption capability of zeolite A modified MCM-41 (A-MCM-41) increased dramatically after modification. The modified MCM-41 was characterized by X-ray diffraction (XRD), nitrogen adsorption–desorption, Fourier Transform Infrared (FTIR) analysis, Transmission electron microscopy (TEM) images, and 29Si and 27Al Magic Angle Spinning Nuclear Magnetic Resonance (MAS NMR) spectra. The modified MCM-41 structure was still retained after impregnated with zeolite A but the surface area and pore diameter decreased due to pore blockage. The adsorption of TC on modified MCM-41 was discussed regarding various parameters such as pH, initial TC concentration, and the reaction time. The pH effects on TC adsorption indicated that the adsorbents had better adsorption performances in acidic and neutral conditions. The adsorption isotherms were fitted well by the Langmuir model. The adsorption kinetics was well described by both pseudo-second order equation and the intra-particle diffusion model. The adsorption behavior in a fixed-bed column system followed Thomas model. The adsorption behavior of TC was the chemical adsorption with an ion exchange process and electrostatic adsorption. PMID:24976787

  11. Novel multi-component hybrids through double luminescent lanthanide unit functionalized zeolite L and titania.

    PubMed

    Chen, Lei; Yan, Bing

    2015-12-01

    Zeolite L (ZL) is functionalized with inside-outside double modification paths (gas disperse ("ship in bottle") and covalently grafting) with two kinds of luminescent lanthanide species (Tb(3+) complex of acetylacetone (AA), lanthanide polyoxometalate (NaLnW10O36·32H2O, abbreviated as LnW10, Ln=Eu, Tb)) to prepare the hybrid materials. The prepared hybrids show the red and green luminescence, which provides a useful path to obtain multi-component lanthanide hybrids. PMID:26125989

  12. [Lifestyle modifications].

    PubMed

    Kawano, Yuhei

    2015-11-01

    Lifestyle modifications are important in the prevention and treatment of hypertension. The Japanese Society of Hypertension Guidelines for the Management of Hypertension (JSH2014) recommend salt reduction (< 6 g/day), increased intake of vegetables/fruit and fish (fish oil), reduced intake of cholesterol and saturated fatty acids, weight loss (body mass index < 25kg/m2), exercise (? 30 min/day), reduction of alcohol intake (? 20-30 mL/day in men, ? 10-20 mL/day in women as ethanol), and quitting smoking. These lifestyle modifications are capable of reducing blood pressure and ameliorating other cardiovascular risk factors. However, the reduction in blood pressure is mild to moderate and the adherence to lifestyle modifications has been still suboptimal. PMID:26619658

  13. UTILITY OF ZEOLITES IN REMOVAL OF INORGANIC AND ORGANIC WATER POLLUTANTS

    EPA Science Inventory

    Zeolites are well known for their ion exchange, adsorption and acid catalysis properties. Different inorganic and organic pollutants have been removed from water at room temperature using various zeolites. Synthetic zeolite Faujasite Y has been used to remove inorganic pollutants...

  14. Zeolite 5A Catalyzed Etherification of Diphenylmethanol

    ERIC Educational Resources Information Center

    Cooke, Jason; Henderson, Eric J.; Lightbody, Owen C.

    2009-01-01

    An experiment for the synthetic undergraduate laboratory is described in which zeolite 5A catalyzes the room temperature dehydration of diphenylmethanol, (C[subscript 6]H[subscript 5])[subscript 2]CHOH, producing 1,1,1',1'-tetraphenyldimethyl ether, (C[subscript 6]H[subscript 5])[subscript 2]CHOCH(C[subscript 6]H[subscript 5])[subscript 2]. The…

  15. SODIUM ZEOLITE A SUPPLEMENTATION TO DAIRY CALVES

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Sodium zeolite A (SZA), an aluminosilicate, has been used in a number of animal studies, but alterations in mineral metabolism and tissue composition have not been fully investigated. The objective of this study was to determine the effects of SZA on mineral metabolism and tissue mineral composition...

  16. ARSENIC SEPARATION FROM WATER USING ZEOLITES

    EPA Science Inventory

    Arsenic is known to be a hazardous contaminant in drinking water. The presence of arsenic in water supplies has been linked to arsenical dermatosis and skin cancer . Zeolites are well known for their ion exchange capacities. In the present work, the potential use of a variety of ...

  17. Dispersion enhanced metal/zeolite catalysts

    DOEpatents

    Sachtler, Wolfgang M. H. (Evanston, IL); Tzou, Ming-Shin (Evanston, IL); Jiang, Hui-Jong (Evanston, IL)

    1987-01-01

    Dispersion stabilized zeolite supported metal catalysts are provided as bimetallic catalyst combinations. The catalyst metal is in a reduced zero valent form while the dispersion stabilizer metal is in an unreduced ionic form. Representative catalysts are prepared from platinum or nickel as the catalyst metal and iron or chromium dispersion stabilizer.

  18. ARSENIC SEPARATION FROM WATER USING ZEOLITES: SYMPOSIUM

    EPA Science Inventory

    NRMRL-ADA-01134 Shevade, S, Ford*, R., and Puls*, R.W. "Arsenic Separation from Water Using Zeolites." In: 222nd ACS National Meeting, ACS Environmental Chemistry Division Symposia, Chicago, IL, 08/26-30/2001. 2001. 04/23/2001 This...

  19. Dispersion enhanced metal/zeolite catalysts

    DOEpatents

    Sachtler, W.M.H.; Tzou, M.S.; Jiang, H.J.

    1987-03-31

    Dispersion stabilized zeolite supported metal catalysts are provided as bimetallic catalyst combinations. The catalyst metal is in a reduced zero valent form while the dispersion stabilizer metal is in an unreduced ionic form. Representative catalysts are prepared from platinum or nickel as the catalyst metal and iron or chromium dispersion stabilizer.

  20. Multicomponent liquid ion exchange with chabazite zeolites

    SciTech Connect

    Robinson, S.M.; Arnold, W.D. Jr.; Byers, C.W.

    1993-10-01

    In spite of the increasing commercial use of zeolites for binary and multicomponent sorption, the understanding of the basic mass-transfer processes associated with multicomponent zeolite ion-exchange systems is quite limited. This study was undertaken to evaluate Na-Ca-Mg-Cs-Sr ion exchange from an aqueous solution using a chabazite zeolite. Mass-transfer coefficients and equilibrium equations were determined from experimental batch-reactor data for single and multicomponent systems. The Langmuir isotherm was used to represent the equilibrium relationship for binary systems, and a modified Dubinin-Polyani model was used for the multicomponent systems. The experimental data indicate that diffusion through the microporous zeolite crystals is the primary diffusional resistance. Macropore diffusion also significantly contributes to the mass-transfer resistance. Various mass-transfer models were compared to the experimental data to determine mass-transfer coefficients. Effective diffusivities were obtained which accurately predicted experimental data using a variety of models. Only the model which accounts for micropore and macropore diffusion occurring in series accurately predicted multicomponent data using single-component diffusivities. Liquid and surface diffusion both contribute to macropore diffusion. Surface and micropore diffusivities were determined to be concentration dependent.

  1. MERCURY SEPARATION FROM POLLUTANT WATER USING ZEOLITES

    EPA Science Inventory

    Arsenic is known to be a hazardous contaminant in drinking water that causes arsenical dermatitis and skin cancer. In the present work, the potential use of a variety of synthetic zeolites for removal of arsenic from water has been examined at room temperature. Experiments have...

  2. Framework Al zoning in zeolite ECR-1.

    PubMed

    Shin, Jiho; Ahn, Nak Ho; Cho, Sung June; Ren, Limin; Xiao, Feng-Shou; Hong, Suk Bong

    2014-02-25

    Rietveld analyses of the synchrotron X-ray diffraction data for various cation forms of zeolite ECR-1 have demonstrated framework Al zoning, which parallels the alternation of Al-rich maz and Al-poor mor layers. This can be further supported by notable differences in the average bond valence of its 10 crystallographically distinct tetrahedral sites. PMID:24409461

  3. Hydrothermal stability of high silica zeolites 

    E-print Network

    Young, David

    1988-01-01

    This thesis concerns the hydrothermal stability of two zeolite molecular sieves with the MFI structure, ZSM-5 and its 'aluminium free' form silicalite. Silicalite was synthesised from low pH alkali metal free aqueous gels at 95°C and characterised...

  4. Zeolite Nanoparticles for Selective Sorption of Plasma Proteins.

    PubMed

    Rahimi, M; Ng, E-P; Bakhtiari, K; Vinciguerra, M; Ahmad, H Ali; Awala, H; Mintova, S; Daghighi, M; Bakhshandeh Rostami, F; de Vries, M; Motazacker, M M; Peppelenbosch, M P; Mahmoudi, M; Rezaee, F

    2015-01-01

    The affinity of zeolite nanoparticles (diameter of 8-12?nm) possessing high surface area and high pore volume towards human plasma proteins has been investigated. The protein composition (corona) of zeolite nanoparticles has been shown to be more dependent on the plasma protein concentrations and the type of zeolites than zeolite nanoparticles concentration. The number of proteins present in the corona of zeolite nanoparticles at 100% plasma (in vivo state) is less than with 10% plasma exposure. This could be due to a competition between the proteins to occupy the corona of the zeolite nanoparticles. Moreover, a high selective adsorption for apolipoprotein C-III (APOC-III) and fibrinogen on the zeolite nanoparticles at high plasma concentration (100%) was observed. While the zeolite nanoparticles exposed to low plasma concentration (10%) exhibited a high selective adsorption for immunoglobulin gamma (i.e. IGHG1, IGHG2 and IGHG4) proteins. The zeolite nanoparticles can potentially be used for selectively capture of APOC-III in order to reduce the activation of lipoprotein lipase inhibition during hypertriglyceridemia treatment. The zeolite nanoparticles can be adapted to hemophilic patients (hemophilia A (F-VIII deficient) and hemophilia B (F-IX deficient)) with a risk of bleeding, and thus might be potentially used in combination with the existing therapy. PMID:26616161

  5. Conversion of Ethanol to Hydrocarbons on Hierarchical HZSM-5 Zeolites

    SciTech Connect

    Ramasamy, Karthikeyan K.; Zhang, He; Sun, Junming; Wang, Yong

    2014-12-15

    This study reports synthesis, characterization, and catalytic activity of the nano-size hierarchical HZSM-5 zeolite with high mesoporosity produced via a solvent evaporation procedure. Further, this study compares hierarchical zeolites with conventional HZSM-5 zeolite with similar Si/Al ratios for the ethanol-to-hydrocarbon conversion process. The catalytic performance of the hierarchical and conventional zeolites was evaluated using a fixed-bed reactor at 360 °C, 300 psig, and a weight hourly space velocity of 7.9 h-1. For the low Si/Al ratio zeolite (~40), the catalytic life-time for the hierarchical HZSM-5 was approximately 2 times greater than the conventional HZSM-5 despite its coking amount deposited 1.6 times higher than conventional HZSM-5. For the high Si/Al ratio zeolite (~140), the catalytic life-time for the hierarchical zeolite was approximately 5 times greater than the conventional zeolite and the amount of coking deposited was 2.1 times higher. Correlation was observed between catalyst life time, porosity, and the crystal size of the zeolite. The nano-size hierarchical HZSM-5 zeolites containing mesoporosity demonstrated improved catalyst life-time compared to the conventional catalyst due to faster removal of products, shorter diffusion path length, and the migration of the coke deposits to the external surface from the pore structure.

  6. Zeolite Nanoparticles for Selective Sorption of Plasma Proteins

    PubMed Central

    Rahimi, M.; Ng, E.-P.; Bakhtiari, K.; Vinciguerra, M.; Ahmad, H. Ali; Awala, H.; Mintova, S.; Daghighi, M.; Bakhshandeh Rostami, F.; de Vries, M.; Motazacker, M. M.; Peppelenbosch, M. P.; Mahmoudi, M.; Rezaee, F.

    2015-01-01

    The affinity of zeolite nanoparticles (diameter of 8–12?nm) possessing high surface area and high pore volume towards human plasma proteins has been investigated. The protein composition (corona) of zeolite nanoparticles has been shown to be more dependent on the plasma protein concentrations and the type of zeolites than zeolite nanoparticles concentration. The number of proteins present in the corona of zeolite nanoparticles at 100% plasma (in vivo state) is less than with 10% plasma exposure. This could be due to a competition between the proteins to occupy the corona of the zeolite nanoparticles. Moreover, a high selective adsorption for apolipoprotein C-III (APOC-III) and fibrinogen on the zeolite nanoparticles at high plasma concentration (100%) was observed. While the zeolite nanoparticles exposed to low plasma concentration (10%) exhibited a high selective adsorption for immunoglobulin gamma (i.e. IGHG1, IGHG2 and IGHG4) proteins. The zeolite nanoparticles can potentially be used for selectively capture of APOC-III in order to reduce the activation of lipoprotein lipase inhibition during hypertriglyceridemia treatment. The zeolite nanoparticles can be adapted to hemophilic patients (hemophilia A (F-VIII deficient) and hemophilia B (F-IX deficient)) with a risk of bleeding, and thus might be potentially used in combination with the existing therapy. PMID:26616161

  7. CO2 SEPARATIONS USING ZEOLITE MEMBRANES

    SciTech Connect

    Richard D. Noble; John L. Falconer

    2001-06-30

    Zeolite and other inorganic molecular sieve membranes have shown potential for separations based on molecular size and shape because of their small pore sized, typically less than 1 nm, and their narrow pore size distribution. The high thermal and chemical stability of these inorganic crystals make them ideal materials for use in high temperature applications such as catalytic membrane reactors. Most of the progress with zeolite membranes has been with MFI zeolites prepared on porous disks and tubes. The MFI zeolite is a medium pore size structure having nearly circular pores with diameters between .53 and .56 nm. Separation experiments through MFI membranes indicate that competitive adsorption separates light gas mixtures. Light gas selectivities are typically small, however, owing to small differences in adsorption strengths and their small sizes relative to the MFI pore opening. Furthermore, competitive adsorption does not work well at high temperature where zeolite membranes are stable and have potential application. Separation by differences in size has a greater potential to work at high temperature than competitive adsorption, but pores smaller than those in MFI zeolites are required. Therefore, some studies focused on the synthesis of a small, 8-membered-pore structures such as zeolite A (0.41-nm pore diameter) and SAPO-34, a chabazite (about .4-nm pore diameter with about 1.4 nm cages) analog. The small pore size of the zeolite A and SAPO-34 structures made the separation of smaller molecules by differences in size possible. Zeolite MFI and SAPO-34 membranes were prepared on the inside surface of porous alumina tubes by hydrothermal synthesis, and single gas and binary mixture permeances were measured to characterize the membrane's performance. A mathematical diffusion model was developed to determine the relative quantities of zeolite and non-zeolite pores in different membranes by modeling the permeation date of CO{sub 2}. This model expresses the total flux through the membrane as the sum of surface diffusion through zeolite pores and viscous flow and Knudsen diffusion through non-zeolite pores. As predicted by the model, the permeance of CO{sub 2} decrease with increasing pressure at constant pressure drop for membranes with few non-zeolite pores, but the permeance increased through viscous flow pores and was constant through pores allowing Knudsen diffusion. Membranes having more non-zeolite pores had lower CO{sub 2}/CH{sub 4} selectivities. The SAPO-34 membranes were characterized for light gas separation applications, and the separation mechanisms were identified. Single gas permeances of CO{sub 2}, N{sub 2}, and CH{sub 4} decreased with increasing kinetic diameter. For the best membrane at 300K, the He and H{sub 2} permeances were less than that of CO{sub 2}, because He, H{sub 2} and CO{sub 2} were small compared to the SAPO-34 pore, and differences in the heat of adsorption determined the permeance order. The small component permeated the fastest in CO{sub 2}/CH{sub 4}, CO{sub 2}/N{sub 2}, N{sub 2}/CH{sub 4}, H{sub 2}/CH{sub 4}, and H{sub 2}/N{sub 2} mixtures between 300 and 470 K. For H{sub 2}/CO{sub 2} mixtures, which were separated by competitive adsorption at room temperature, the larger component permeated faster below 400K. The room temperature CO{sub 2}/CH{sub 4} selectivity was 36 and decreased with temperature. The H{sub 2}/CH{sub 4} mixture selectivity was 8 and constant with temperature up to 480 K. Calcination, slow temperature cycles, and exposure to water vapor had no permanent effect on membrane performance, but temperature changes of approximately 30 K/min decreased the membrane's effectiveness. The effects of humidity on gas permeation were studied with SAPO-34 membranes of different qualities. Membranes with high CO{sub 2}/CH{sub 4} selectivities (greater than 20) were stable in water vapor under controlled conditions, but degradation was seen for some membranes. The degradation opened non-SAPO-34 pores that were larger than SAPO-34 pores as shown by the IC{sub 4}H{sub 10} permeance, C

  8. Vitrification of copper flotation waste.

    PubMed

    Karamanov, Alexander; Aloisi, Mirko; Pelino, Mario

    2007-02-01

    The vitrification of an hazardous iron-rich waste (W), arising from slag flotation of copper production, was studied. Two glasses, containing 30wt% W were melted for 30min at 1400 degrees C. The first batch, labeled WSZ, was obtained by mixing W, blast furnace slag (S) and zeolite tuff (Z), whereas the second, labeled WG, was prepared by mixing W, glass cullet (G), sand and limestone. The glass frits showed high chemical durability, measured by the TCLP test. The crystallization of the glasses was evaluated by DTA. The crystal phases formed were identified by XRD resulting to be pyroxene and wollastonite solid solutions, magnetite and hematite. The morphology of the glass-ceramics was observed by optical and scanning electron microscopy. WSZ composition showed a high rate of bulk crystallization and resulted to be suitable for producing glass-ceramics by a short crystallization heat-treatment. WG composition showed a low crystallization rate and good sinterability; glass-ceramics were obtained by sinter-crystallization of the glass frit. PMID:17064848

  9. Seeding of Porous Alumina Substrate with MFI Zeolite Nanocrystals using Spin-coating Technique

    E-print Network

    Baroud, T.

    Zeolite membranes offer a great potential for applications in many challenging separation processes. Controlled thickness of zeolite membrane allows high flux and excellent selectivity commercially available; producing ...

  10. Atomic sites and stability of Cs+ captured within zeolitic nanocavities

    PubMed Central

    Yoshida, Kaname; Toyoura, Kazuaki; Matsunaga, Katsuyuki; Nakahira, Atsushi; Kurata, Hiroki; Ikuhara, Yumi H.; Sasaki, Yukichi

    2013-01-01

    Zeolites have potential application as ion-exchangers, catalysts and molecular sieves. Zeolites are once again drawing attention in Japan as stable adsorbents and solidification materials of fission products, such as 137Cs+ from damaged nuclear-power plants. Although there is a long history of scientific studies on the crystal structures and ion-exchange properties of zeolites for practical application, there are still open questions, at the atomic-level, on the physical and chemical origins of selective ion-exchange abilities of different cations and detailed atomic structures of exchanged cations inside the nanoscale cavities of zeolites. Here, the precise locations of Cs+ ions captured within A-type zeolite were analyzed using high-resolution electron microscopy. Together with theoretical calculations, the stable positions of absorbed Cs+ ions in the nanocavities are identified, and the bonding environment within the zeolitic framework is revealed to be a key factor that influences the locations of absorbed cations. PMID:23949184

  11. Advanced zeolites used in FCC catalysts boost motor octane number

    SciTech Connect

    Letzsch, W.S.; Magee, J.S.; Upson, L.L.; Valeri, F. )

    1988-10-31

    Fluid catalytic cracking catalysts that contain an advanced zeolite called LZ-210, have been shown, by commercial trials, to increase the motor octane number (MON) of the FCC gasoline produced. The zeolite crystal utilizes lower unit cell size, lower sodium in the zeolite, less alumina debris in the zeolite structure, and silica reinsertion into the zeolite structure to accomplish the MON increase. Data from commercial trials are presented to support the MON increases, along with some explanations of how the advanced zeolite accomplishes them. A strong gasoline market and the removal of lead have combined to place a premium on clear gasoline octanes. Because gasoline from fluid catalytic cracking units is the largest segment of the refinery pool (up to 40%), its octane numbers are particularly important. Traditional emphasis has been on the research octance number (RON) but motor octanes frequently limit the blending process.

  12. Zeolite and swine inoculum effect on poultry manure biomethanation

    NASA Astrophysics Data System (ADS)

    Kougias, P. G.; Fotidis, I. A.; Zaganas, I. D.; Kotsopoulos, T. A.; Martzopoulos, G. G.

    2013-03-01

    Poultry manure is an ammonia-rich substrate that inhibits methanogenesis, causing severe problems to the anaerobic digestion process. In this study, the effect of different natural zeolite concentrations on the mesophilic anaerobic digestion of poultry waste inoculated with well-digested swine manure was investigated. A significant increase in methane production was observed in treatments where zeolite was added, compared to the treatment without zeolite.Methane production in the treatment with 10 g dm-3 of natural zeolite was found to be 109.75% higher compared to the treatment without zeolite addition. The results appear to be influenced by the addition of zeolite, which reduces ammonia toxicity in anaerobic digestion and by the ammonia-tolerant swine inoculum.

  13. Atomic sites and stability of Cs+ captured within zeolitic nanocavities.

    PubMed

    Yoshida, Kaname; Toyoura, Kazuaki; Matsunaga, Katsuyuki; Nakahira, Atsushi; Kurata, Hiroki; Ikuhara, Yumi H; Sasaki, Yukichi

    2013-01-01

    Zeolites have potential application as ion-exchangers, catalysts and molecular sieves. Zeolites are once again drawing attention in Japan as stable adsorbents and solidification materials of fission products, such as (137)Cs(+) from damaged nuclear-power plants. Although there is a long history of scientific studies on the crystal structures and ion-exchange properties of zeolites for practical application, there are still open questions, at the atomic-level, on the physical and chemical origins of selective ion-exchange abilities of different cations and detailed atomic structures of exchanged cations inside the nanoscale cavities of zeolites. Here, the precise locations of Cs(+) ions captured within A-type zeolite were analyzed using high-resolution electron microscopy. Together with theoretical calculations, the stable positions of absorbed Cs(+) ions in the nanocavities are identified, and the bonding environment within the zeolitic framework is revealed to be a key factor that influences the locations of absorbed cations. PMID:23949184

  14. Atomic sites and stability of Cs+ captured within zeolitic nanocavities

    NASA Astrophysics Data System (ADS)

    Yoshida, Kaname; Toyoura, Kazuaki; Matsunaga, Katsuyuki; Nakahira, Atsushi; Kurata, Hiroki; Ikuhara, Yumi H.; Sasaki, Yukichi

    2013-08-01

    Zeolites have potential application as ion-exchangers, catalysts and molecular sieves. Zeolites are once again drawing attention in Japan as stable adsorbents and solidification materials of fission products, such as 137Cs+ from damaged nuclear-power plants. Although there is a long history of scientific studies on the crystal structures and ion-exchange properties of zeolites for practical application, there are still open questions, at the atomic-level, on the physical and chemical origins of selective ion-exchange abilities of different cations and detailed atomic structures of exchanged cations inside the nanoscale cavities of zeolites. Here, the precise locations of Cs+ ions captured within A-type zeolite were analyzed using high-resolution electron microscopy. Together with theoretical calculations, the stable positions of absorbed Cs+ ions in the nanocavities are identified, and the bonding environment within the zeolitic framework is revealed to be a key factor that influences the locations of absorbed cations.

  15. Elution of cesium from zeolite IE-96 using oxalic acid

    SciTech Connect

    Sills, J.A.; Russell, R.L.; Patello, G.K.

    1996-12-31

    The West Valley Demonstration Project (WVDP) is preparing to begin vitrification at the site in West Valley, NY. The wastes to be vitrified include high-level radioactive waste (HLW) generated as a result of the former reprocessing operations and cesium-loaded zeolite, a high-activity waste, generated from WVDP pretreatment operations. These pretreatment operations used zeolite in an ion-exchange process designed to remove radioactive cesium from liquid HLW. Zeolite transfer operations, in which the majority of the cesium-loaded zeolite is transferred to a tank containing HLW, are currently being performed in preparation for vitrification. Due to operating constraints and tank design, a portion of the zeolite will remain in the tank after the transfer occurs. The use of oxalic acid to elute the radioactive cesium from the zeolite to decrease the radioactivity remaining in the tank is being evaluated.

  16. The ADOR mechanism for the synthesis of new zeolites.

    PubMed

    Eliášová, Pavla; Opanasenko, Maksym; Wheatley, Paul S; Shamzhy, Mariya; Mazur, Michal; Nachtigall, Petr; Roth, Wieslaw J; Morris, Russell E; ?ejka, Ji?í

    2015-10-21

    A novel methodology, called ADOR (assembly-disassembly-organisation-reassembly), for the synthesis of zeolites is reviewed here in detail. The ADOR mechanism stems from the fact that certain chemical weakness against a stimulus may be present in a zeolite framework, which can then be utilized for the preparation of new solids through successive manipulation of the material. In this review, we discuss the critical factors of germanosilicate zeolites required for application of the ADOR protocol and describe the mechanism of hydrolysis, organisation and condensation to form new zeolites starting from zeolite UTL. Last but not least, we discuss the potential of this methodology to form other zeolites and the prospects for future investigations. PMID:25946705

  17. Zeolite catalysis in conversion of cellulosics. Annual report

    SciTech Connect

    Tsao, G.T.

    1994-02-01

    The authors have studied the kinetics of oxylose/xylulose isomerization in significant detail over a variety of zeolites and obtained the pseudo-first order reaction rate constants. The authors have found that HY zeolite is still the best material and zeolites are more selective than homogeneous acid catalysts where decomposition of the sugar compounds is much faster. They have completed, as described in the Year 2 Work Plan, the study of cellobiose hydrolysis with an ion exchange resin. The kinetics of the solid-catalyzed reaction is qualitatively similar to that for catalysis by homogeneous acids. The planned program of NMR studies has revealed the dynamics of sugar molecules within the zeolite cavities. Two chemisorbed and a physisorbed state have been identified in HY zeolite. A new state, accounting for as much as a half of the sugar, has been found in ZSM-5 zeolite.

  18. Preparation of Robust, Thin Zeolite Membrane Sheet for Molecular Separation

    SciTech Connect

    Liu, Wei; Zhang, Jian; Canfield, Nathan L.; Saraf, Laxmikant V.

    2011-10-19

    This paper reports a feasibility study on the preparation of zeolite membrane films on a thin, porous metal support sheet (50-{micro}m thick). Zeolite sodium A (NaA) and silicalite zeolite frameworks are chosen to represent synthesis of respective hydrophilic-type and hydrophobic-type zeolite membranes on this new support. It is found that a dense, continuous inter-grown zeolite crystal layer at a thickness less than 2 {micro}m can be directly deposited on such a support by using direct and secondary growth techniques. The resulting membrane shows excellent adhesion on the metal sheet. Molecular-sieving functions of the prepared membranes are characterized with ethanol/water separation, CO2 separation, and air dehumidification. The results show great potential to make flexible metal-foil-like zeolite membranes for a range of energy conversion and environmental applications.

  19. Chemical Interactions in Multimetal/Zeolite Catalysts

    SciTech Connect

    Sachtler, Wolfgang M. H.

    2004-04-16

    This two-year project has led to a significant improvement in the fundamental understanding of the catalytic action of zeolite-supported redox catalysts. It turned out to be essential that we could combine four strategies for the preparation of catalysts containing transition metal (TM) ions in zeolite cavities: (1) ion exchange from aqueous solution; (2) chemical vapor deposition (CVD) of a volatile halide onto a zeolite in its acidic form; (3) solid state ion exchange; and (4) hydrothermal synthesis of a zeolite having TM ions in its lattice, followed by a treatment transporting these ions to ''guest positions''. Technique (2) enables us to position more TM ions into cavities than permitted by the conventional technique (1).viz one positive charge per Al centered tetrahedron in the zeolite lattice. The additional charge is compensated by ligands to the TM ions, for instance in oxo-ions such as (GaO){sup +} or dinuclear [Cu-O-Cu]{sup 2+}. While technique (3) is preferred over CVD where volatile halides are not available, technique (4) leads to rather isolated ''ex lattice'' oxo-ions. Such oxo-ions tend to be mono-nuclear, in contrast to technique (2) which preferentially creates dinuclear oxo-ions of the same TM element. A favorable element for the present research was that the PI is also actively engaged in a project on the reduction of nitrogen oxides, sponsored by EMSI program of the National Science Foundation and the US Department of Energy, Office of Science. This combination created a unique opportunity to test and analyze catalysts for the one step oxidation of benzene to phenol and compare them with catalysts for the reduction of nitrogen oxides, using hydrocarbons as the reductant. In both projects catalysts have been used which contain Fe ions or oxo-ions in the cavities the zeolite MFI, often called ZSM-5. With Fe as the TM-element and MFI as the host zeolite we found that catalysts with high Fe content, prepared by technique (2) were optimal for the De-NO{sub x} reaction, but extremely unselective for benzene oxidation to phenol. Conversely, the catalysts prepared with (4) had the highest turnover frequency for benzene oxidation, but performed very poorly for NO{sub x} reduction with so-butane. In fact the Fe concentration in the former catalysts were so low that it was necessary to design a special experimental program for the sole purpose of showing that it is really the Fe which catalyzes the benzene oxidation, not some acid center as has been proposed by other authors. For this purpose we used hydrogen sulfide to selectively poison the Fe sites, without deactivating the acidic sites. In addition we could show that the hydrothermal treatment of catalysts prepared by technique (4) is essential to transform iron ions in the zeolite lattice to ''ex lattice ions'' in guest positions. That line of the work required very careful experimentation, because a hydrothermal treatment of a zeolite containing Fe ions in its cavities can also lead to agglomeration of such ions to nano-particles of iron oxide which lowers the selectivity for the desired formation of phenol. This part of the program showed convincingly that indeed Fe is responsible for the benzene oxidation catalysis. The results and conclusion of this work, including the comparison of different catalysts, was published in a number of papers in the scientific literature, listed in the attached list. In these papers also our analysis of the reaction orders and the possible mechanism of the used test reaction are given.

  20. Ionic Liquid assisted Synthesis of Zeolite-TON

    PubMed Central

    Tian, Yuyang; McPherson, Matthew J; Wheatley, Paul S; Morris, Russell E

    2014-01-01

    An ionic liquid assisted strategy for the synthesis of zeolitic material is reported. This strategy is a solid state synthetic method and the ionic liquid is employed as structure directing agent. A TON-type zeolite, which contains one-dimensional 10-member-ring, is successfully synthesized with the assistance of the ionic liquid, 1-ethyl-3-methylimidazolium bromide. This finding improves our understanding about the challenge of ionothermally synthesizing siliceous and aluminosilicate zeolites. PMID:26213423

  1. Zeolite membranes - a review and comparison with MOFs.

    PubMed

    Rangnekar, N; Mittal, N; Elyassi, B; Caro, J; Tsapatsis, M

    2015-10-21

    The latest developments in zeolite membranes are reviewed, with an emphasis on the synthesis techniques, including seed assembly and secondary growth methods. This review also discusses the current industrial applications of zeolite membranes, the feasibility of their use in membrane reactors and their hydrothermal stability. Finally, zeolite membranes are compared with metal-organic framework (MOF) membranes and the latest advancements in MOF and mixed matrix membranes are highlighted. PMID:26155855

  2. Large zeolites - Why and how to grow in space

    NASA Technical Reports Server (NTRS)

    Sacco, Albert, Jr.

    1991-01-01

    The growth of zeolite crystals which are considered to be the most valuable catalytic and adsorbent materials of the chemical processing industry are discussed. It is proposed to use triethanolamine as a nucleation control agent to control the time release of Al in a zeolite A solution and to increase the average and maximum crystal size by 25-50 times. Large zeolites could be utilized to make membranes for reactors/separators which will substantially increase their efficiency.

  3. Zeolite (clinoptilolite) as feed additive to reduce manure mineral content.

    PubMed

    Leung, S; Barrington, S; Wan, Y; Zhao, X; El-Husseini, B

    2007-12-01

    Clinoptilolite (a species of zeolite) as grower hog feed additive can potentially improve nutrient ingestion and lower manure nutrient levels. A first objective was to establish the optimal particle size of the zeolite powder, as a fine size increases the adsorption surface while a coarse size can facilitate handling. The second objective tested the effect of feeding zeolite on manure nutrient levels. For the first objective, three zeolite powders (250-500 microm; 50-250 microm, and 50-500 microm) were exposed to an NH(4)(+) solution under a pH of either 7.0 or 2.0. The resulting solutions were tested for cation exchange. A commercial zeolite was also tested for the pH of 2.0 to evaluate zeolite stability. At 0%, 5% and 10% humidity, the same three particle size powders were subjected to shear tests to determine the zeolite's angle of friction. For the second objective using metabolic cages, female hogs were subjected to one of four rations (a control and three with zeolite) while collecting and analyzing their manures. For the first objective, the coarse particle zeolite performed best, adsorbing 158 and 123 Cmol(+)/kg of NH(4)(+) under neutral and acid pH, respectively, and releasing an equivalent amount of minerals only under neutral pH. The commercial zeolite with less clinoptilolite released more Al, Fe, Cu and Pb, showing less stability. The high internal angle of friction of zeolite did not vary with particle size and moisture, indicating funnel flow under gravity. For the second objective, hogs fed a zeolite diet produced manure with 15% and 22% less N and P, respectively, and demonstrated a better feed conversion, although not statistically significant (P>0.05). These results show that there is some potential in using high quality clinoptilolite in the ration of grower hogs. PMID:16905313

  4. Development of low-cost integrated zeolite collector

    NASA Astrophysics Data System (ADS)

    Tchernev, D. I.

    1981-07-01

    The optimum zeolite loading and the best zeolite for this purpose were determined by careful mathematical analysis, followed by experimental test, to confirm the theoretical results. The integrated collector design was then completed and the collector was constructed. After sealing and vacuum testing the zeolite panels and heat exchanges, the collector was coated with flat black paint and provided with double glazing, aluminum frame and insulation. Preliminary testing indicates close agreement with theoretical predictions of its performance.

  5. Rapid crystallization of faujasitic zeolites: mechanism and application to zeolite membrane growth on polymer supports.

    PubMed

    Severance, Michael; Wang, Bo; Ramasubramanian, Kartik; Zhao, Lin; Ho, W S Winston; Dutta, Prabir K

    2014-06-17

    Zeolites are microporous, crystalline aluminosilicates with the framework made up of T-O-T (T = Si, Al) bonds and enclosed cages and channels of molecular dimensions. Influencing and manipulating the nucleation and growth characteristics of zeolites can lead to novel frameworks and morphologies, as well as decreased crystallization time. In this study, we show that manipulating the supersaturation during synthesis of zeolite X/Y (FAU) via dehydration led to extensive nucleation. Controlled addition of water to this nucleated state promotes the transport of nutrients, with a 4-fold increase in the rate of crystal growth, as compared to conventional hydrothermal process. Structural signature of the nucleated state was obtained by electron microscopy, NMR, and Raman spectroscopy. This extensively intermediate nucleated state was isolated and used as the starting material for zeolite membrane synthesis on porous polymer supports, with membrane formation occurring within an hour. With this time frame for growth, it becomes practical to fabricate zeolite/polymer membranes using roll-to-roll technology, thus making possible new commercial applications. PMID:24758695

  6. Comparing gas separation performance between all known zeolites and their zeolitic imidazolate framework counterparts.

    PubMed

    Gómez-Álvarez, Paula; Hamad, Said; Haranczyk, Maciej; Ruiz-Salvador, A Rabdel; Calero, Sofia

    2015-12-14

    To find optimal porous materials for adsorption-based separations is a challenging task due to the extremely large number of possible pore topologies and compositions. New porous material classes such as Metal Organic Frameworks (MOFs) are emerging, and hope to replace traditionally used materials such as zeolites. Computational screening offers relatively fast searching for candidate structures as well as side-by-side comparisons between material families. This work is pioneering at examining the families comprised by the experimentally known zeolites and their respective Zeolitic Imidazolate Framework (ZIF) counterparts in the context of a number of environmental and industrial separations involving carbon dioxide, nitrogen, methane, oxygen, and argon. Additionally, unlike related published work, here all the targeted structures have been previously relaxed through energy minimization. On the first level of characterization, we considered a detailed pore characterization, identifying 24 zeolites as promising candidates for gas separation based on adsorbate sizes. The second level involved interatomic potential-based calculations to assess the adsorption performance of the materials. We found no correlation in the values of heat of adsorption between zeolites and ZIFs sharing the same topology. A number of structures were identified as potential experimental targets for CO2/N2, and CO2/CH4 affinity-based separations. PMID:26600432

  7. Method for the recovery of silver from silver zeolite

    DOEpatents

    Reimann, G.A.

    1985-03-05

    High purity silver is recovered from silver exchanged zeolite used to capture radioactive iodine from nuclear reactor and nuclear fuel reprocessing environments. The silver exchanged zeolite is heated with slag formers to melt and fluidize the zeolite and release the silver, the radioactivity removing with the slag. The silver containing metallic impurities is remelted and treated with oxygen and a flux to remove the metal impurities. About 98% of the silver in the silver exchanged zeolite having a purity of 99% or better is recoverable by the method.

  8. Method for the recovery of silver from silver zeolite

    DOEpatents

    Reimann, George A. (Idaho Falls, ID)

    1986-01-01

    High purity silver is recovered from silver exchanged zeolite used to capture radioactive iodine from nuclear reactor and nuclear fuel reprocessing environments. The silver exchanged zeolite is heated with slag formers to melt and fluidize the zeolite and release the silver, the radioactivity removing with the slag. The silver containing metallic impurities is remelted and treated with oxygen and a flux to remove the metal impurities. About 98% of the silver in the silver exchanged zeolite having a purity of 99% or better is recoverable by the method.

  9. Zeolite Crystal Growth in Microgravity and on Earth

    NASA Technical Reports Server (NTRS)

    2003-01-01

    The Center for Advanced Microgravity Materials Processing (CAMMP), a NASA-sponsored Research Partnership Center, is working to improve zeolite materials for storing hydrogen fuel. CAMMP is also applying zeolites to detergents, optical cables, gas and vapor detection for environmental monitoring and control, and chemical production techniques that significantly reduce by-products that are hazardous to the environment. Shown here are zeolite crystals (top) grown in a ground control experiment and grown in microgravity on the USML-2 mission (bottom). Zeolite experiments have also been conducted aboard the International Space Station.

  10. Impact of Zeolite Aging in Hot Liquid Water on Activity for Acid-Catalyzed Dehydration of Alcohols.

    PubMed

    Vjunov, Aleksei; Derewinski, Miroslaw A; Fulton, John L; Camaioni, Donald M; Lercher, Johannes A

    2015-08-19

    The location and stability of Brønsted acid sites catalytically active in zeolites during aqueous phase dehydration of alcohols were studied on the example of cyclohexanol. The catalytically active hydronium ions originate from Brønsted acid sites (BAS) of the zeolite that are formed by framework tetrahedral Si atom substitution by Al. Al K-edge extended X-ray absorption fine structure (EXAFS) and (27)Al magic angle spinning (MAS) nuclear magnetic resonance (NMR) spectroscopies in combination with density functional theory (DFT) calculations are used to determine the distribution of tetrahedral Al sites (Al T-sites) both qualitatively and quantitatively for both parent and HBEA catalysts aged in water prior to catalytic testing. The aging procedure leads to partial degradation of the zeolite framework evidenced from the decrease of material crystallinity (XRD) as well as sorption capacity (BET). With the exception of one commercial zeolite sample, which had the highest concentration of framework silanol-defects, there is no evidence of Al coordination modification after aging in water. The catalyst weight-normalized dehydration rate correlated best with the sum of strong and weak Brønsted acidic protons both able to generate the hydrated hydronium ions. All hydronium ions were equally active for the acid-catalyzed reactions in water. Zeolite aging in hot water prior to catalysis decreased the weight normalized dehydration reaction rate compared to that of the parent HBEA, which is attributed to the reduced concentration of accessible Brønsted acid sites. Sites are hypothesized to be blocked due to reprecipitation of silica dissolved during framework hydrolysis in the aging procedure. PMID:26237038

  11. Acidity of two-dimensional zeolites.

    PubMed

    Rybicki, Marcin; Sauer, Joachim

    2015-10-14

    Hybrid quantum mechanics:molecular mechanics (QM/MM) calculations of absolute deprotonation energies are performed with periodic boundary conditions for Brønsted sites of aluminosilicate bilayers with various Al/Si ratios (two-dimensional zeolite). The supercell method is applied and density functional theory is used. Much lower values are obtained (1042, 1069 and 1091 kJ mol(-1) for Al/Si = 1/63, 1/7 and 1/3, respectively) than those for bulk zeolites (1233 kJ mol(-1) for H-chabazite with Al/Si = 1/11). We ascribe the much lower deprotonation energy to the smaller effective dielectric constant (1.6-1.9) of an ultra-thin dielectric in a vacuum compared to that of the corresponding bulk systems (3.0 for H-chabazite), which leads to a better stabilization of the charge created upon deprotonation. PMID:26437870

  12. Computational studies of water adsorption in zeolites

    SciTech Connect

    Zygmunt, S.A.; Curtiss, L.A.; Iton, L.E.

    1995-05-01

    We have performed high-level ab initio calculations using Hartree-Fock (HF) theory, Moller-Plesset perturbation theory (MP2), and density-functional theory (DFT) to study the geometry and energetics of the adsorption complex involving H{sub 2}O and the Bronsted acid site in the zeolite H-ZSM-5. These calculations use aluminosilicate cluster models for the zeolite framework with as many as 28 T atoms (T=Si, Al). We included geometry optimization in the local vicinity of the acid site at the MP2 and DFT levels of theory for the smallest cluster, while in the larger clusters this was done at the HF/6-31G(d) level of theory. We have also calculated corrections for zero-point energies, extensions to higher basis sets, and higher levels of electron correlation. Results for the adsorption energy and geometry of this complex are reported and compared with previous theoretical and experimental values.

  13. In Situ SAXS/WAXS of Zeolite Microwave Synthesis: NaY, NaA, and Beta Zeolites

    SciTech Connect

    Panzarella,B.; Tompsett, G.; Conner, W.; Jones, K.

    2007-01-01

    A custom waveguide apparatus is constructed to study the microwave synthesis of zeolites by in situ small-angle X-ray scattering (SAXS) and wide-angle X-ray scattering (WAXS). The WR-284 waveguide is used to heat precursor solutions using microwaves at a frequency of 2.45 GHz. The reaction vessels are designed to include sections of thin-walled glass, which permit X-rays to pass through the precursor solutions with minimal attenuation. Slots were machined into the waveguide to provide windows for X-ray energy to enter and scatter from solutions during microwave heating. The synthesis of zeolites with conventional heating is also studied using X-ray scattering in the same reactor. SAXS studies show that the crystallization of beta zeolite and NaY zeolite is preceded by a reorganization of nanosized particles in their precursor solutions or gels. The evolution of these particles during the nucleation and crystallization stages of zeolite formation depends on the properties of the precursor solution. The synthesis of NaA and NaX zeolites and sodalite from a single zeolite precursor is studied by microwave and conventional heating. Microwave heating shifts the selectivity of this synthesis in favor of NaA and NaX over sodalite; conventional heating leads to the formation of sodalite for synthesis from the same precursor. The use of microwave heating also led to a more rapid onset of NaA zeolite product crystallization compared to conventional heating. Pulsed and continuous microwave heating are compared for zeolite synthesis. The resulting rates of formation of the zeolite products, and the relative amounts of the products determined from the WAXS spectra, are similar when either pulsed or continuous microwave heating is applied in the reactor while maintaining the same synthesis temperature. The consequences of these results in terms of zeolite synthesis are discussed.

  14. Characterization and antibacterial activity of silver exchanged regenerated NaY zeolite from surfactant-modified NaY zeolite.

    PubMed

    Salim, Mashitah Mad; Malek, Nik Ahmad Nizam Nik

    2016-02-01

    The antibacterial activity of regenerated NaY zeolite (thermal treatment from cetyltrimethyl ammonium bromide (CTAB)-modified NaY zeolite and pretreatment with Na ions) loaded with silver ions were examined using the broth dilution minimum inhibitory concentration (MIC) method against Escherichia coli (E. coli ATCC 11229) and Staphylococcus aureus (S. aureus ATCC 6538). X-ray diffraction (XRD), attenuated total reflectance-Fourier transform infrared (ATR-FTIR) spectroscopy, field emission scanning electron microscopy (FESEM), energy dispersive X-ray (EDX) and chemical elemental analyses were used to characterize the regenerated NaY and AgY zeolites. The XRD patterns indicated that the calcination and addition of silver ions on regenerated NaY zeolite did not affect the structure of the regenerated NaY zeolite as the characteristic peaks of the NaY zeolite were retained, and no new peaks were observed. The regenerated AgY zeolite showed good antibacterial activity against both bacteria strains in distilled water, and the antibacterial activity of the samples increased with increasing Ag loaded on the regenerated AgY zeolite; the regenerated AgY zeolite was more effective against E. coli than S. aureus. However, the antibacterial activity of the regenerated AgY was not effective in saline solution for both bacteria. The study showed that CTAB-modified NaY zeolite materials could be regenerated to NaY zeolite using thermal treatment (550°C, 5h) and this material has excellent performance as an antibacterial agent after silver ions loading. PMID:26652350

  15. Zeolites in Eocene basaltic pillow lavas of the Siletz River Volcanics, Central Coast Range, Oregon.

    USGS Publications Warehouse

    Keith, T.E.C.; Staples, L.W.

    1985-01-01

    Zeolites and associated minerals occur in a tholeiitic basaltic pillow lava sequence. Although the zeolite assemblages are similar to those found in other major zeolite occurrences in basaltic pillow lavas, regional zoning of the zeolite assemblages is not apparent. The formation of the different assemblages is discussed.-D.F.B.

  16. Oxygen transport in zeolite Y measured by quenching of encapsulated tris(bipyridyl)ruthenium

    E-print Network

    Dutta, Prabir K.

    Oxygen transport in zeolite Y measured by quenching of encapsulated tris(bipyridyl)ruthenium Abstract This study deals with emission quenching of zeolite encapsulated trisbipyridyl ruthenium (II) (Ru the migration of O2 within zeolites using the emis- sion quenching of zeolite encapsulated ruthenium

  17. Photochemical template removal and spatial patterning of zeolite MFI thin films using UV/ozone treatment

    E-print Network

    Parikh, Atul N.

    Photochemical template removal and spatial patterning of zeolite MFI thin films using UV of thin films of microporous or zeolite materials. We prepared thin-films of a high silica zeolite leads to complete removal of template (structure-direc- ting-agent) from zeolite films comparable

  18. Selective thermal and photooxidation of hydrocarbons in zeolites by oxygen

    DOEpatents

    Frei, Heinz (Berkeley, CA); Blatter, Fritz (Basel, CH); Sun, Hai (Saint Charles, MO)

    1999-01-01

    A process for selective thermal oxidation or photooxidation of hydrocarbons adsorbed onto zeolite matrices. A highly selective thermal oxidation and photooxidation of unsubstituted or alkyl substituted alkanes, alkenes, aromatics and cycloalkyls in solvent free zeolites under dark thermal conditions or under irradiation with visible light. The process oxidizes hydrocarbons almost completely selectively without substantial production of byproducts.

  19. Selective thermal oxidation of hydrocarbons in zeolites by oxygen

    DOEpatents

    Frei, Heinz (Berkeley, CA); Blatter, Fritz (Basel, CH); Sun, Hai (Saint Charles, MO)

    2000-01-01

    A process for selective thermal oxidation of hydrocarbons adsorbed onto zeolite matrices. A highly selective thermal oxidation of unsubstituted or alkyl substituted alkanes, alkenes, aromatics and cycloalkyls is carried out in solvent free zeolites under dark thermal conditions. The process oxidizes hydrocarbons almost completely selectively without substantial production of byproducts.

  20. CATION CONTROLLED SINGLET OXYGEN MEDIATED OXIDATION OF OLEFINS WITHIN ZEOLITES

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Oxidation of trialkyl olefins has been performed within zeolites employing thionin as the singlet oxygen sensitizer. Unusual selectivity in favor of secondary hydroperoxides is observed within zeolites. In light of the fact that in solution such a selectivity is never observed the selectivity report...

  1. Silanization-Based Zeolite Crystallization: Participation Degree and Pathway.

    PubMed

    Yan, Yueer; Azhati, Arepati; Guo, Xiao; Zhang, Yahong; Tang, Yi

    2015-08-17

    A clear and deep understanding of zeolite crystallization with the addition of organosilane is desirable for the reasonable design and preparation of hierarchical zeolites. Herein, the effects of different organosilanes on zeolite crystallization were systematically studied. It was found that organosilane plays the role of an inhibitor in the silanization-based zeolite preparation, and this inhibition effect was determined by its participation degree. An organosilane with a high participation degree can result in the prolongation of nucleation and growth periods of zeolite as well as the variation of product properties. More importantly, a dynamic participation pathway of organosilane is proposed, that is, the growth of zeolite is accompanied by the continuous removal of organosilane, leading to an increase of product crystallinity as well as the decrease of mesoporosity. This study gives a new insight into the role that organosilane plays in zeolite crystallization, which will help to direct the rational selection of organosilane and design of crystallization condition for the optimal synthesis of hierarchical zeolites. PMID:26173899

  2. Crewmember working on the mid deck Zeolite Crystal Growth experiment.

    NASA Technical Reports Server (NTRS)

    1992-01-01

    View showing Payload Specialist Bonnie Dunbar, in the mid deck, conducting the Zeolite Crystal Growth (ZCG) Experiment in the mid deck stowage locker work area. View shows assembly of zeolite sample in the metal autoclave cylinders prior to insertion into the furnace.

  3. Factors that Determine Zeolite Stability in Hot Liquid Water.

    PubMed

    Zhang, Lu; Chen, Kuizhi; Chen, Banghao; White, Jeffery L; Resasco, Daniel E

    2015-09-16

    The susceptibility of zeolites to hot liquid water may hamper their full utilization in aqueous phase processes, such as those involved in biomass conversion and upgrading reactions. Interactions of zeolites with water strongly depend on the presence of hydrophilic moieties including Brønsted acid sites (BAS), extraframework cations, and silanol defects, which facilitate wetting of the surface. However, it is not clear which of these moieties are responsible for the susceptibility of zeolites to liquid water. Previous studies have offered contradictory explanations because the role of each of these characteristics has not been investigated independently. In this work, a systematic comparison has been attempted by relating crystallinity losses to the variation of each of the five zeolite characteristics that may influence their stability in liquid water, including number of BAS, Si-O-Si bonds, framework type, silanol defects, and extraframework Al. In this study, we have systematically monitored the crystallinity changes of a series of HY, H-ZSM-5, and H-? zeolite samples with varying Si/Al ratio, density of BAS, zeolite structure, and density of silanol defects upon exposure to liquid water at 200 °C. The results of this comparison unambiguously indicate that the density of silanol defects plays the most crucial role in determining susceptibility of zeolites to hot liquid water. By functionalizing the silanol defects with organosilanes, the hydrophobicity of defective zeolite is increased and the tolerance to hot liquid water is significantly enhanced. PMID:26301890

  4. FUNDAMENTALS AND APPLICATIONS OF PERVAPORATION THROUGH ZEOLITE MEMBRANES

    EPA Science Inventory

    Zeolite membranes are well suited for separating liquid-phase mixtures by pervaporation because of their molecular-sized pores and their hydrophilic/hydrophobic nature, and the first commercial application of zeolite membranes has been for dehydrating organics [1]. Because of ...

  5. Zeolites in the Pine Ridge Indian Reservation, South Dakota

    USGS Publications Warehouse

    Raymond, William H.; Bush, Alfred L.; Gude, Arthur J., 3rd

    1982-01-01

    Zeolites of possible commercial value occur in the Brule Formation of Oligocene age and the Sharps Formation (Harksen, 1961) of Miocene age which crop out in a wide area in the northern part of the Pine Ridge Indian Reservation. The thickness of the zeolite-bearing Interval and the extent of areas within the Interval which contain significant amounts of zeolites are far greater than was expected prior to this investigation. The shape of the zeolite-bearing Interval is tabular and the dimensions of Its exposure are roughly 10 ml x 200 mi x 150 ft (16 km x 160 km x 45 m) thick. Within the study area, there are tracts in which the zeolite resource potential is significant (see pl. 2). This report is intended to inform the Oglala Sioux Tribe of some of the most promising zeolite occurrences. Initial steps can then be taken by the Tribe toward possible development of the resources, should they wish to do so. The data contained herein identify areas of high zeolite potential, but are not adequate to establish economic value for the deposits. If development is recommended by the tribal government, we suggest that the tribal government contact companies involved in research and production of natural zeolites and provide them with the data in this report.

  6. Preferential orientations of structure directing agents in zeolites.

    PubMed

    Dib, Eddy; Gimenez, Antoine; Mineva, Tzonka; Alonso, Bruno

    2015-10-14

    The local structure of as-synthesised silicalite-1 zeolites is modified using asymmetric R(Pr)3N(+) structure directing agents. Using multi-nuclear NMR ((1)H, (13)C, (14)N, (19)F, (29)Si), we show for the first time the ability of these cations to adopt preferential orientations at the zeolite channels' crossing. PMID:26346931

  7. Selective thermal and photooxidation of hydrocarbons in zeolites by oxygen

    DOEpatents

    Frei, Heinz (Berkeley, CA); Blatter, Fritz (Basel, CH); Sun, Hai (Saint Charles, MO)

    2001-01-01

    A process for a combined selective thermal oxidation and photooxidation of hydrocarbons adsorbed onto zeolite matrices. A highly combined selective thermal oxidation and photooxidation of unsubstituted or alkyl substituted alkanes, alkenes, aromatics and cycloalkyls in solvent free zeolites under dark thermal conditions or under irradiation with visible light. The process oxidizes hydrocarbons almost completely selectively without substantial production of byproducts.

  8. Ion exchange in a zeolite-molten chloride system

    SciTech Connect

    Woodman, R.H.; Pereira, C.

    1997-07-01

    Electrometallurgical treatment of spent nuclear fuel results in a secondary waste stream of radioactive fission products dissolved in chloride salt. Disposal plans include a waste form that can incorporate chloride forms featuring one or more zeolites consolidated with sintered glass. A candidate method for incorporating fission products in the zeolites is passing the contaminated salt over a zeolite column for ion exchange. To date, the molten chloride ion-exchange properties of four zeolites have been investigated for this process: zeolite A, IE95{reg_sign}, clinoptilolite, and mordenite. Of these, zeolite A has been the most promising. Treating zeolite 4A, the sodium form of zeolite A , with the solvent salt for the waste stream-lithium-potassium chloride of eutectic melting composition, is expected to provide a material with favorable ion-exchange properties for the treatment of the waste salt. The authors constructed a pilot-plant system for the ion-exchange column. Initial results indicate that there is a direct relationship between the two operating variable of interest, temperature, and initial sodium concentration. Also, the mass ratio has been about 3--5 to bring the sodium concentration of the effluent below 1 mol%.

  9. Selective thermal and photooxidation of hydrocarbons in zeolites by oxygen

    DOEpatents

    Frei, H.; Blatter, F.; Sun, H.

    1999-06-22

    A process is described for selective thermal oxidation or photooxidation of hydrocarbons adsorbed onto zeolite matrices. A highly selective thermal oxidation and photooxidation of unsubstituted or alkyl substituted alkanes, alkenes, aromatics and cycloalkyls in solvent free zeolites under dark thermal conditions or under irradiation with visible light. The process oxidizes hydrocarbons almost completely selectively without substantial production of byproducts. 19 figs.

  10. In-situ x-ray absorption study of copper films in ground watersolutions

    SciTech Connect

    Kvashnina, K.O.; Butorin, S.M.; Modin, A.; Soroka, I.; Marcellini, M.; Nordgren, J.; Guo, J.-H.; Werme, L.

    2007-10-29

    This study illustrates how the damage from copper corrosion can be reduced by modifying the chemistry of the copper surface environment. The surface modification of oxidized copper films induced by chemical reaction with Cl{sup -} and HCO{sub 3}{sup -} in aqueous solutions was monitored by in situ X-ray absorption spectroscopy. The results show that corrosion of copper can be significantly reduced by adding even a small amount of sodium bicarbonate. The studied copper films corroded quickly in chloride solutions, whereas the same solution containing 1.1 mM HCO{sub 3}{sup -} prevented or slowed down the corrosion processes.

  11. Mineral resource of the month: natural and synthetic zeolites

    USGS Publications Warehouse

    Virta, R.

    2008-01-01

    Robert Virta, mineral commodity specialist for the U.S. Geological Survey, prepared the following information about the zeolite industry. Volcanic rocks containing natural zeolites — hydrated aluminosilicate minerals that contain alkaline and alkaline-earth metals — have been mined worldwide for more than 1,000 years for use as cements and building stone. For centuries, people thought natural zeolites occurred only in small amounts inside cavities of volcanic rock. But in the 1950s and early 1960s, large zeolite deposits were discovered in volcanic tuffs in the western United States and in marine tuffs in Italy and Japan. And since then, similar deposits have been found around the world, from Hungary to Cuba to New Zealand. The discovery of these larger deposits made commercial mining of natural zeolite possible.

  12. Potential and actual uses of zeolites in crop protection.

    PubMed

    De Smedt, Caroline; Someus, Edward; Spanoghe, Pieter

    2015-10-01

    In this review, it is demonstrated that zeolites have a potential to be used as crop protection agents. Similarly to kaolin, zeolites can be applied as particle films against pests and diseases. Their honeycomb framework, together with their carbon dioxide sorption capacity and their heat stress reduction capacity, makes them suitable as a leaf coating product. Furthermore, their water sorption capacity and their smaller particle sizes make them effective against fungal diseases and insect pests. Finally, these properties also ensure that zeolites can act as carriers of different active substances, which makes it possible to use zeolites for slow-release applications. Based on the literature, a general overview is provided of the different basic properties of zeolites as promising products in crop protection. PMID:25727795

  13. A pair distribution function analysis of zeolite beta

    SciTech Connect

    Martinez-Inesta, M.M.; Peral, I.; Proffen, T.; Lobo, R.F.

    2010-07-20

    We describe the structural refinement of zeolite beta using the local structure obtained with the pair distribution function (PDF) method. A high quality synchrotron and two neutron scattering datasets were obtained on two samples of siliceous zeolite beta. The two polytypes that make up zeolite beta have the same local structure; therefore refinement of the two structures was possible using the same experimental PDF. Optimized structures of polytypes A and B were used to refine the structures using the program PDFfit. Refinements using only the synchrotron or the neutron datasets gave results inconsistent with each other but a cyclic refinement with the two datasets gave a good fit to both PDFs. The results show that the PDF method is a viable technique to analyze the local structure of disordered zeolites. However, given the complexity of most zeolite frameworks, the use of both X-ray and neutron radiation and high-resolution patterns is essential to obtain reliable refinements.

  14. Demystifying Controlling Copper Corrosion

    EPA Science Inventory

    The LCR systematically misses the highest health and corrosion risk sites for copper. Additionally, there are growing concerns for WWTP copper in sludges and discharge levels. There are many corrosion control differences between copper and lead. This talk explains the sometimes c...

  15. Influence of NaA Zeolite Crystal Expansion/Contraction on Zeolite Membrane Separations

    SciTech Connect

    Sorenson, Stephanie G; Payzant, E Andrew; Gibbons, Will T; Soydas, Belma; Kita, Hidetoshi; Noble, Richard D; Falconer, John L.

    2011-01-01

    In-situ powder XRD measurements showed that the NaA zeolite unit cell contracts and expands upon adsorption, and these changes in zeolite crystal size correlate with permeation changes through NaA zeolite membranes. These membranes had high pervaporation selectivities, even though gas permeation was mainly through defects, as indicated by Knudsen selectivities for gases. At 300 K and a thermodynamic activity of 0.03, water contracted the NaA crystals by 0.22 vol%, and this contraction increased the helium flux through two NaA membranes by approximately 80%. Crystal contraction also increased the fluxes of i-butane during vapor permeation and i-propanol (IPA) during pervaporation (~ 0.03 wt% water). At activities above 0.07, water expanded NaA crystals and correspondingly decreased the membrane fluxes of helium, i-butane, and IPA. Similarly, methanol contracted NaA crystals by 0.05 vol% at an activity of 0.02, and this contraction slightly increased the helium and i-butane fluxes through a NaA membrane. Above an activity of 0.06, methanol expanded the crystals, and the fluxes of helium and i-butane through a NaA membrane decreased. The adsorbate-induced changes explain some pervaporation behavior reported by others, and they indicate that crystal expansion and contraction may increase or decrease zeolite NaA membrane selectivity by changing the defect sizes.

  16. Probing zeolites with organic molecules: Supercages of X and Y zeolites are superpolar

    SciTech Connect

    Uppili, S.; Thomas, K.J.; Crompton, E.M.; Ramamurthy, V.

    2000-01-11

    Supercages of Li{sup +}- and Na{sup +}-exchanged X and Y zeolites are much more polar than even water. The extent of polarity depends on the nature and the number of cations present within a supercage. The polarity of Li{sup +}- and Na{sup +}-exchanged X and Y zeolites decreases in the presence of water. In presence of water the contribution of cations toward polarity is much smaller than water itself. In this study polarity has been monitored with organic probe molecules, Nile red, pyrene 1-carboxaldehyde and coumarin-500. A connection between polarity and electric field within a cage has also been established. Since the supercages are much more polar than all organic solvents, they can be characterized as superpolar. Because of this one may be able to achieve excited-state switching of carbonyl compounds within a zeolite while such may not be possible in organic solvents. The n{pi}*-{pi}{pi}* state switching of acetophenones is easily achieved within a zeolite while such does not occur in polar solvent methanol-ethanol mixture.

  17. Effect of copper sulphate treatment on natural phytoplanktonic communities.

    PubMed

    Le Jeune, Anne-Hélène; Charpin, Marie; Deluchat, Véronique; Briand, Jean-François; Lenain, Jean-François; Baudu, Michel; Amblard, Christian

    2006-12-01

    Copper sulphate treatment is widely used as a global and empirical method to remove or control phytoplankton blooms without precise description of the impact on phytoplanktonic populations. The effects of two copper sulphate treatments on natural phytoplanktonic communities sampled in the spring and summer seasons, were assessed by indoor mesocosm experiments. The initial copper-complexing capacity of each water sample was evaluated before each treatment. The copper concentrations applied were 80 microg l(-1) and 160 microg l(-1) of copper, below and above the water complexation capacity, respectively. The phytoplanktonic biomass recovered within a few days after treatment. The highest copper concentration, which generated a highly toxic environment, caused a global decrease in phytoplankton diversity, and led to the development and dominance of nanophytoplanktonic Chlorophyceae. In mesocosms treated with 80 microg l(-1) of copper, the effect on phytoplanktonic community size-class structure and composition was dependent on seasonal variation. This could be related to differences in community composition, and thus to species sensitivity to copper and to differences in copper bioavailability between spring and summer. Both treatments significantly affected cyanobacterial biomass and caused changes in the size-class structure and composition of phytoplanktonic communities which may imply modifications of the ecosystem structure and function. PMID:17095105

  18. [Zeolite catalysis in conversion of cellulosics

    SciTech Connect

    Tsao, G.T.

    1992-12-31

    To transform biomass into fermentable substrate for yeast, we are using zeolites instead of enzymes to catalyze the two bottleneck reactions in biomass conversion, xylose isomerization and ceuobiose hydrolysis. The experimental results on these reactions carried out over various zeolites and other catalysts are presented herein. The advantages and disadvantages of using these catalysts over enzymes are also discussed. Heterogeneous solid catalysts other than zeolites has been employed for cellobiose-to-glucose hydrolysis. The size and shape selectivity that makes zeoutes unique for some reactions can add diffusional hindrance. We have spent some time screening various known solid acidic catalysts. We report that a class of cationic ion exchange resins in the acidified form (e.g. Amberlite) has worked well as an acidic catalyst in hydrolyzing cellobiose to glucose. Our experimental results, together with those obtained from a homogeneous acid catalyst (e.g. sulfuric acid) for comparison are provided. Having succeeded in finding an alternative solid acid catalyst for hydrolysis, we explored other solid resin or other homogeneous but non-enzyme catalyst to carry out the xylose-to-xylulose isomerization. A fairly extensive search has been made. We explored the use of sodium aluminates in the homogeneous phase isomerization of glucose to fructose and obtained a very high conversion of glucose to fructose with the final mixture containing 85% of fructose instead of the common 45%. Fructose apparently complexes with aluminates, and its equilibrium concentration is shifted to considerably higher values than permitted by simple glucose/fructose equilibrium. We have recently found a number of catalysts capable of promoting isomerization between aldoses and ketoses. One solid resin, known as polyvinyl pyridine (PVP), is able to convert xylose to xylulose at a pH below 7. Our usage of alternative isomerization catalysts, including PVP, are described.

  19. [Zeolite catalysis in conversion of cellulosics

    SciTech Connect

    Tsao, G.T.

    1992-01-01

    To transform biomass into fermentable substrate for yeast, we are using zeolites instead of enzymes to catalyze the two bottleneck reactions in biomass conversion, xylose isomerization and ceuobiose hydrolysis. The experimental results on these reactions carried out over various zeolites and other catalysts are presented herein. The advantages and disadvantages of using these catalysts over enzymes are also discussed. Heterogeneous solid catalysts other than zeolites has been employed for cellobiose-to-glucose hydrolysis. The size and shape selectivity that makes zeoutes unique for some reactions can add diffusional hindrance. We have spent some time screening various known solid acidic catalysts. We report that a class of cationic ion exchange resins in the acidified form (e.g. Amberlite) has worked well as an acidic catalyst in hydrolyzing cellobiose to glucose. Our experimental results, together with those obtained from a homogeneous acid catalyst (e.g. sulfuric acid) for comparison are provided. Having succeeded in finding an alternative solid acid catalyst for hydrolysis, we explored other solid resin or other homogeneous but non-enzyme catalyst to carry out the xylose-to-xylulose isomerization. A fairly extensive search has been made. We explored the use of sodium aluminates in the homogeneous phase isomerization of glucose to fructose and obtained a very high conversion of glucose to fructose with the final mixture containing 85% of fructose instead of the common 45%. Fructose apparently complexes with aluminates, and its equilibrium concentration is shifted to considerably higher values than permitted by simple glucose/fructose equilibrium. We have recently found a number of catalysts capable of promoting isomerization between aldoses and ketoses. One solid resin, known as polyvinyl pyridine (PVP), is able to convert xylose to xylulose at a pH below 7. Our usage of alternative isomerization catalysts, including PVP, are described.

  20. Growth of large zeolite crystals in space

    NASA Technical Reports Server (NTRS)

    Sacco, A., Jr.; Dixon, A.; Thompson, R.; Scott, G.; Ditr, J.

    1988-01-01

    Synthesis studies performed using close analogs of triethanolamine (TEA) have shown that all three hydroxyl groups and the amine group in this molecule are necessary to provide nucleation suppression. Studies using C-13 nuclear magnetic resonance (NMR) revealed that the hydroxyl ions and the amine group are involved in the formation of an aluminum complex. It was also shown that silicate species fo not interact this way with TEA in an alkaline solution. These results suggest that successful aluminum complexation leads to nucleation in zeolite-A crystallization.

  1. Structural analysis of hierarchically organized zeolites

    PubMed Central

    Mitchell, Sharon; Pinar, Ana B.; Kenvin, Jeffrey; Crivelli, Paolo; Kärger, Jörg; Pérez-Ramírez, Javier

    2015-01-01

    Advances in materials synthesis bring about many opportunities for technological applications, but are often accompanied by unprecedented complexity. This is clearly illustrated by the case of hierarchically organized zeolite catalysts, a class of crystalline microporous solids that has been revolutionized by the engineering of multilevel pore architectures, which combine unique chemical functionality with efficient molecular transport. Three key attributes, the crystal, the pore and the active site structure, can be expected to dominate the design process. This review examines the adequacy of the palette of techniques applied to characterize these distinguishing features and their catalytic impact. PMID:26482337

  2. Structural analysis of hierarchically organized zeolites

    NASA Astrophysics Data System (ADS)

    Mitchell, Sharon; Pinar, Ana B.; Kenvin, Jeffrey; Crivelli, Paolo; Kärger, Jörg; Pérez-Ramírez, Javier

    2015-10-01

    Advances in materials synthesis bring about many opportunities for technological applications, but are often accompanied by unprecedented complexity. This is clearly illustrated by the case of hierarchically organized zeolite catalysts, a class of crystalline microporous solids that has been revolutionized by the engineering of multilevel pore architectures, which combine unique chemical functionality with efficient molecular transport. Three key attributes, the crystal, the pore and the active site structure, can be expected to dominate the design process. This review examines the adequacy of the palette of techniques applied to characterize these distinguishing features and their catalytic impact.

  3. Structural analysis of hierarchically organized zeolites.

    PubMed

    Mitchell, Sharon; Pinar, Ana B; Kenvin, Jeffrey; Crivelli, Paolo; Kärger, Jörg; Pérez-Ramírez, Javier

    2015-01-01

    Advances in materials synthesis bring about many opportunities for technological applications, but are often accompanied by unprecedented complexity. This is clearly illustrated by the case of hierarchically organized zeolite catalysts, a class of crystalline microporous solids that has been revolutionized by the engineering of multilevel pore architectures, which combine unique chemical functionality with efficient molecular transport. Three key attributes, the crystal, the pore and the active site structure, can be expected to dominate the design process. This review examines the adequacy of the palette of techniques applied to characterize these distinguishing features and their catalytic impact. PMID:26482337

  4. Distribution of metal and adsorbed guest species in zeolites

    SciTech Connect

    Chmelka, B.F.

    1989-12-01

    Because of their high internal surface areas and molecular-size cavity dimensions, zeolites are used widely as catalysts, shape- selective supports, or adsorbents in a variety of important chemical processes. For metal-catalyzed reactions, active metal species must be dispersed to sites within the zeolite pores that are accessible to diffusing reactant molecules. The distribution of the metal, together with transport and adsorption of reactant molecules in zeolite powders, are crucial to ultimate catalyst performance. The nature of the metal or adsorbed guest distribution is known, however, to be dramatically dependent upon preparatory conditions. Our objective is to understand, at the molecular level, how preparatory treatments influence the distribution of guest species in zeolites, in order that macroscopic adsorption and reaction properties of these materials may be better understood. The sensitivity of xenon to its adsorption environment makes {sup 129}Xe NMR spectroscopy an important diagnostic probe of metal clustering and adsorbate distribution processes in zeolites. The utility of {sup 129}Xe NMR depends on the mobility of the xenon atoms within the zeolite-guest system, together with the length scale of the sample heterogeneity being studied. In large pore zeolites containing dispersed guest species, such as Pt--NaY, {sup 129}Xe NMR is insensitive to fine structural details at room temperature.

  5. Zeolite Crystal Growth (ZCG) Flight on USML-2

    NASA Technical Reports Server (NTRS)

    Sacco, Albert, Jr.; Bac, Nurcan; Warzywoda, Juliusz; Guray, Ipek; Marceau, Michelle; Sacco, Teran L.; Whalen, Leah M.

    1997-01-01

    The extensive use of zeolites and their impact on the world's economy has resulted in many efforts to characterize their structure, and improve the knowledge base for nucleation and growth of these crystals. The zeolite crystal growth (ZCG) experiment on USML-2 aimed to enhance the understanding of nucleation and growth of zeolite crystals, while attempting to provide a means of controlling the defect concentration in microgravity. Zeolites A, X, Beta, and Silicalite were grown during the 16 day - USML-2 mission. The solutions where the nucleation event was controlled yielded larger and more uniform crystals of better morphology and purity than their terrestrial/control counterparts. The external surfaces of zeolite A, X, and Silicalite crystals grown in microgravity were smoother (lower surface roughness) than their terrestrial controls. Catalytic studies with zeolite Beta indicate that crystals grown in space exhibit a lower number of Lewis acid sites located in micropores. This suggests fewer structural defects for crystals grown in microgravity. Transmission electron micrographs (TEM) of zeolite Beta crystals also show that crystals grown in microgravity were free of line defects while terrestrial/controls had substantial defects.

  6. Synthesis, characterization and reactivity of transition-metal-containing zeolites

    SciTech Connect

    Rossin, J.A.

    1986-01-01

    Transition metal containing zeolites (zeolite A and ZSM-5) were prepared by addition of various transition metal containing substrates to zeolite synthesis gels. Crystal growth data were recorded in order to determine the influence of the transition metal species on the rate of crystal growth. X-ray diffraction, oxygen adsorption, FTIR and SEM were utilized to evaluate crystal purity. X-ray photoelectron spectroscopy (XPS), chemical analysis and electron microprobe analysis were performed in order to ascertain the position (intrazeolitic versus surface) and homogeneity of the transition metal. It was concluded that intrazeolitic transition metals are produced by the novel procedure presented in this work. 1-Hexane hydroformylation by rhodium zeolite A showed intrazeolitic rhodium to migrate to the external surface of the zeolite. However, in the presence of a solution and surface rhodium poison, intrazeolitic rhodium was found to hydroformylate 1-hexene exclusively to heptanal. Ruthenium containing zeolite A was evaluated under CO-hydrogenation conditions. No migration of intrazeolitic ruthenium to the external surface of the zeolite was observed over the course of the reaction. The product distribution obtained for this catalyst did not follow a log normal behavior. Also, loss of zeolite crystallinity was observed following the reaction. Cobalt ZSM-5 was evaluated under CO-hydrogenation conditions. No migration of cobalt to the external surface of the zeolite occurred. XPS analysis of the catalyst following various stages of the reaction indicated that intrazeolitic cobalt was not reduced to the zero valent state. Consequently, the non-zero valent cobalt was not capable of hydrogenating carbon monoxide.

  7. Zeolite crystal growth in space - What has been learned

    NASA Technical Reports Server (NTRS)

    Sacco, A., Jr.; Thompson, R. W.; Dixon, A. G.

    1993-01-01

    Three zeolite crystal growth experiments developed at WPI have been performed in space in last twelve months. One experiment, GAS-1, illustrated that to grow large, crystallographically uniform crystals in space, the precursor solutions should be mixed in microgravity. Another experiment evaluated the optimum mixing protocol for solutions that chemically interact ('gel') on contact. These results were utilized in setting the protocol for mixing nineteen zeolite solutions that were then processed and yielded zeolites A, X and mordenite. All solutions in which the nucleation event was influenced produced larger, more 'uniform' crystals than did identical solutions processed on earth.

  8. Method of preparing sodalite from chloride salt occluded zeolite

    DOEpatents

    Lewis, Michele A. (Naperville, IL); Pereira, Candido (Lisle, IL)

    1997-01-01

    A method for immobilizing waste chloride salts containing radionuclides and hazardous nuclear material for permanent disposal starting with a substantially dry zeolite and sufficient glass to form leach resistant sodalite with occluded radionuclides and hazardous nuclear material. The zeolite and glass are heated to a temperature up to about 1000.degree. K. to convert the zeolite to sodalite and thereafter maintained at a pressure and temperature sufficient to form a sodalite product near theoretical density. Pressure is used on the formed sodalite to produce the required density.

  9. Method of preparing sodalite from chloride salt occluded zeolite

    DOEpatents

    Lewis, M.A.; Pereira, C.

    1997-03-18

    A method is described for immobilizing waste chloride salts containing radionuclides and hazardous nuclear material for permanent disposal starting with a substantially dry zeolite and sufficient glass to form leach resistant sodalite with occluded radionuclides and hazardous nuclear material. The zeolite and glass are heated to a temperature up to about 1000 K to convert the zeolite to sodalite and thereafter maintained at a pressure and temperature sufficient to form a sodalite product near theoretical density. Pressure is used on the formed sodalite to produce the required density.

  10. Method of preparing sodalite from chloride salt occluded zeolite A

    SciTech Connect

    Lewis, M.A.; Pereira, C.

    1995-12-31

    A method is described for immobilizing waste chloride salts containing radionuclides and hazardous nuclear material for permanent disposal starting with a substantially dry zeolite and sufficient glass to form leach resistance sodalite with occluded radionuclides and hazardous nuclear material. The zeolite and glass are heated to a temperature up to about 1,000 K to convert the zeolite to sodalite and thereafter maintained at a pressure and temperature sufficient to form a sodalite product near theoretical density. Pressure is used on the formed sodalite to produce the required density.

  11. Hierarchical zeolites from class F coal fly ash

    NASA Astrophysics Data System (ADS)

    Chitta, Pallavi

    Fly ash, a coal combustion byproduct is classified as types class C and class F. Class C fly ash is traditionally recycled for concrete applications and Class F fly ash often disposed in landfills. Class F poses an environmental hazard due to disposal and leaching of heavy metals into ground water and is important to be recycled in order to mitigate the environmental challenges. A major recycling option is to reuse the fly ash as a low-cost raw material for the production of crystalline zeolites, which serve as catalysts, detergents and adsorbents in the chemical industry. Most of the prior literature of fly ash conversion to zeolites does not focus on creating high zeolite surface area zeolites specifically with hierarchical pore structure, which are very important properties in developing a heterogeneous catalyst for catalysis applications. This research work aids in the development of an economical process for the synthesis of high surface area hierarchical zeolites from class F coal fly ash. In this work, synthesis of zeolites from fly ash using classic hydrothermal treatment approach and fusion pretreatment approach were examined. The fusion pretreatment method led to higher extent of dissolution of silica from quartz and mullite phases, which in turn led to higher surface area and pore size of the zeolite. A qualitative kinetic model developed here attributes the difference in silica content to Si/Al ratio of the beginning fraction of fly ash. At near ambient crystallization temperatures and longer crystallization times, the zeolite formed is a hierarchical faujasite with high surface area of at least 360 m2/g. This work enables the large scale recycling of class F coal fly ash to produce zeolites and mitigate environmental concerns. Design of experiments was used to predict surface area and pore sizes of zeolites - thus obviating the need for intense experimentation. The hierarchical zeolite catalyst supports tested for CO2 conversion, yielded hydrocarbons up to C9, a performance attesting the hierarchal pore structure. The preliminary techno-economic feasibility assessment demonstrates a net energy saving of 75% and cost saving of 63% compared to the commercial zeolite manufacturing process.

  12. Design of composite photocatalyst of TiO2 and Y-zeolite for degradation of 2-propanol in the gas phase under UV and visible light irradiation.

    PubMed

    Kamegawa, Takashi; Ishiguro, Yasushi; Kido, Ryota; Yamashita, Hiromi

    2014-01-01

    Hydrophobic Y-zeolite (SiO2/Al2O3 = 810) and TiO2 composite photocatalysts were designed by using two different types of TiO2 precursors, i.e., titanium ammonium oxalate and ammonium hexafluorotitanate. The porous structure, surface property and state of TiO2 were investigated by various characterization techniques. By using an ammonium hexafluorotitanate as a precursor, hydrophobic modification of the Y-zeolite surface and realizing visible light sensitivity was successfully achieved at the same time after calcination at 773 K in the air. The prepared sample still maintained the porous structure of Y-zeolite and a large surface area. Highly crystalline anatase TiO2 was also formed on the Y-zeolite surface by the role of fluorine in the precursor. The usages of ammonium hexafluorotitanate were effective for the improvement of the photocatalytic performance of the composite in the degradation of 2-propanol in the gas phase under UV and visible light (? > 420 nm) irradiation. PMID:25314607

  13. Uniformly microsized luminescent materials obtained through a solid state reaction of WO{sub 3} with Ln{sup 3+}-exchanged zeolite L at 700 °C

    SciTech Connect

    Wang, Yige; Fang, Yi; Zhang, Wenjun; Zhang, Li; Chen, Yuhuan; Yu, Xiaoyan

    2013-06-01

    Graphical abstract: We have reported the modification of Ln3+/ZL microcrystals by the tungstate-oxygen species via a solid state reaction of WO{sub 3} and Ln{sup 3+}-exchanged zeolite L at 700 °C. Highlights: ? Luminescent materials were obtained from zeolite L crystals. ? The materials show characteristic luminescence of Eu{sup 3+} and Tb{sup 3+} ions. ? The framework of zeolite L crystals has been kept during the annealing process. ? Energy transfer from tungstate-oxygen species to lanthanide was confirmed. - Abstract: In this work, we report the uniformly microsized luminescent materials prepared by a solid state reaction of WO{sub 3} and Ln{sup 3+}-exchanged zeolite L at 700 °C. The obtained materials were investigated by SEM, XRD and photoluminescence spectroscopy. The influence of tungstate-oxygen species on the morphology and luminescence of the materials were discussed in detail. Energy transfer from the tungstate-oxygen species to Eu{sup 3+} and Tb{sup 3+} ions have been demonstrated by the photoluminescence spectra, implying the loading of tungstate-oxygen species into the nanochannels of the crystals and the close proximity of which to Eu{sup 3+} ions.

  14. Quantitatively Probing the Al Distribution in Zeolites

    SciTech Connect

    Vjunov, Aleksei; Fulton, John L.; Huthwelker, Thomas; Pin, Sonia; Mei, Donghai; Schenter, Gregory K.; Govind, Niranjan; Camaioni, Donald M.; Hu, Jian Z.; Lercher, Johannes A.

    2014-06-11

    The degree of substitution of Si4+ by Al3+ in the oxygen-terminated tetrahedra (Al T-sites) of zeolites determines the concentration of ion-exchange and Brønsted acid sites. As the location of the tetrahedra and the associated subtle variations in bond angles influence the acid strength, quantitative information about Al T-sites in the framework is critical to rationalize catalytic properties and to design new catalysts. A quantitative analysis is reported that uses a combination of extended X-ray absorption fine structure (EXAFS) analysis and 27Al MAS NMR spectroscopy supported by DFT-based molecular dynamics simulations. To discriminate individual Al atoms, sets of ab initio EXAFS spectra for various T-sites are generated from DFT-based molecular dynamics simulations allowing quantitative treatment of the EXAFS single- and multiple-photoelectron scattering processes out to 3-4 atom shells surrounding the Al absorption center. It is observed that identical zeolite types show dramatically different Al-distributions. A preference of Al for T-sites that are part of one or more 4-member rings in the framework over those T-sites that are part of only 5- and 6-member rings in the HBEA150 sample has been determined from a combination of these methods. This work was supported by the U. S. Department of Energy (DOE), Office of Basic Energy Sciences, Division of Chemical Sciences, Geosciences & Biosciences.

  15. Catalytic pyrolysis using UZM-44 aluminosilicate zeolite

    DOEpatents

    Nicholas, Christopher P; Boldingh, Edwin P

    2014-04-29

    A new family of aluminosilicate zeolites designated UZM-44 has been synthesized. These zeolites are represented by the empirical formula. Na.sub.nM.sub.m.sup.k+T.sub.tAl.sub.1-xE.sub.xSi.sub.yO.sub.z where "n" is the mole ratio of Na to (Al+E), M represents a metal or metals from zinc, Group 1, Group 2, Group 3 and or the lanthanide series of the periodic table, "m" is the mole ratio of M to (Al+E), "k" is the average charge of the metal or metals M, T is the organic structure directing agent or agents, and E is a framework element such as gallium. The process involves contacting a carbonaceous biomass feedstock with UZM-44 at pyrolysis conditions to produce pyrolysis gases comprising hydrocarbons. The catalyst catalyzes a deoxygenation reaction converting oxygenated hydrocarbons into hydrocarbons and removing the oxygen as carbon oxides and water. A portion of the pyrolysis gases is condensed to produce low oxygen biomass-derived pyrolysis oil.

  16. Catalytic pyrolysis using UZM-44 aluminosilicate zeolite

    DOEpatents

    Nicholas, Christopher P; Boldingh, Edwin P

    2013-12-17

    A new family of aluminosilicate zeolites designated UZM-44 has been synthesized. These zeolites are represented by the empirical formula Na.sub.nM.sub.m.sup.k+T.sub.tAl.sub.1-xE.sub.xSi.sub.yO.sub.z where "n" is the mole ratio of Na to (Al+E), M represents a metal or metals from zinc, Group 1, Group 2, Group 3 and or the lanthanide series of the periodic table, "m" is the mole ratio of M to (Al+E), "k" is the average charge of the metal or metals M, T is the organic structure directing agent or agents, and E is a framework element such as gallium. The process involves contacting a carbonaceous biomass feedstock with UZM-44 at pyrolysis conditions to produce pyrolysis gases comprising hydrocarbons. The catalyst catalyzes a deoxygenation reaction converting oxygenated hydrocarbons into hydrocarbons and removing the oxygen as carbon oxides and water. A portion of the pyrolysis gases is condensed to produce low oxygen biomass-derived pyrolysis oil.

  17. Comparative study of CO{sub 2} capture by carbon nanotubes, activated carbons, and zeolites

    SciTech Connect

    Chungsying Lu; Hsunling Bai; Bilen Wu; Fengsheng Su; Jyh Feng Hwang

    2008-09-15

    Carbon nanotubes (CNTs), granular activated carbon (GAC), and zeolites were modified by 3-aminopropyl-triethoxysilane (APTS) and were selected as adsorbents to study their physicochemical properties and adsorption behaviors of CO{sub 2} from gas streams. The surface nature of these adsorbents was changed after the modification, which make them adsorb more CO{sub 2} gases. Under the same conditions, the modified CNTs possess the greatest adsorption capacity of CO{sub 2}, followed by the modified zeolites and then the modified GAC. The mechanism of CO{sub 2} adsorption on these adsorbents appears mainly attributable to physical force, which makes regeneration of spent adsorbents at a relatively low temperature become feasible. The APTS-modified CNTs show good performance of CO{sub 2} adsorption as compared to many types of modified carbon and silica adsorbents reported in the literature. This suggests that the APTS-modified CNTs are efficient CO{sub 2} adsorbents and that they possess potential applications for CO{sub 2} capture from gas streams. 27 refs., 11 figs., 3 tabs.

  18. Enhanced perchloroethylene reduction in column systems using surfactant-modified zeolite/zero-valent iron pellets.

    PubMed

    Zhang, Pengfei; Tao, Xian; Li, Zhaohui; Bowman, Robert S

    2002-08-15

    Surfactant- (hexadecyltrimethylammonium, HDTMA) modified zeolite (SMZ)/zero-valent iron (ZVI) pellets having high hydraulic conductivity (9.7 cm s(-1)), high surface area (28.2 m2 g(-1)), and excellent mechanical strength were developed. Laboratory column experiments were conducted to evaluate the performance of the pellets for perchloroethylene (PCE) sorption/reduction under dynamic flow-through conditions. PCE reduction rates with the surfactant-modified pellets (SMZ/ZVI) were three times higher than the reduction rates with the unmodified pellets (zeolite/ZVI). We speculate that enhanced sorption of PCE directly onto iron surface by iron-bound HDTMA and/or an increased local PCE concentration in the vicinity of iron surface due to sorption of PCE by SMZ contributed to the enhanced PCE reduction by the SMZ/ZVI pellets. Trichloroethylene and cis-dichloroethylene production during PCE reduction increased with the surfactant-modified pellets, indicating that the surfactant modification may have favored hydrogenolysis over beta-elimination. PCE reduction rate constants increased as the travel velocity increased from 0.5 to 1.9 m d(-1), suggesting that the reduction of PCE in the column systems was mass transfer limited. PMID:12214654

  19. Single-site trinuclear copper oxygen clusters in mordenite for selective conversion of methane to methanol

    PubMed Central

    Grundner, Sebastian; Markovits, Monica A.C.; Li, Guanna; Tromp, Moniek; Pidko, Evgeny A.; Hensen, Emiel J.M.; Jentys, Andreas; Sanchez-Sanchez, Maricruz; Lercher, Johannes A.

    2015-01-01

    Copper-exchanged zeolites with mordenite structure mimic the nuclearity and reactivity of active sites in particulate methane monooxygenase, which are enzymes able to selectively oxidize methane to methanol. Here we show that the mordenite micropores provide a perfect confined environment for the highly selective stabilization of trinuclear copper-oxo clusters that exhibit a high reactivity towards activation of carbon–hydrogen bonds in methane and its subsequent transformation to methanol. The similarity with the enzymatic systems is also implied from the similarity of the reversible rearrangements of the trinuclear clusters occurring during the selective transformations of methane along the reaction path towards methanol, in both the enzyme system and copper-exchanged mordenite. PMID:26109507

  20. Molecular Chemistry in a Zeolite: Genesis of a Zeolite Y-Supported Ruthenium Complex Catalyst

    SciTech Connect

    Ogino, I.; Gates, B.C.

    2009-05-22

    Dealuminated zeolite Y was used as a crystalline support for a mononuclear ruthenium complex synthesized from cis-Ru(acac){sub 2}(C{sub 2}H{sub 4}){sub 2}. Infrared (IR) and extended X-ray absorption fine structure spectra indicated that the surface species were mononuclear ruthenium complexes, Ru(acac)(C{sub 2}H{sub 4}){sub 2}{sup 2+}, tightly bonded to the surface by two Ru-O bonds at Al{sup 3+} sites of the zeolite. The maximum loading of the anchored ruthenium complexes was one complex per two Al{sup 3+} sites; at higher loadings, some of the cis-Ru(acac){sub 2}(C{sub 2}H{sub 4}){sub 2} was physisorbed. In the presence of ethylene and H{sub 2}, the surface-bound species entered into a catalytic cycle for ethylene dimerization and operated stably. IR data showed that at the start of the catalytic reaction, the acac ligand of the Ru(acac)(C{sub 2}H{sub 4}){sub 2}{sup 2+} species was dissociated and captured by an Al{sup 3+} site. Ethylene dimerization proceeded 600 times faster with a cofeed of ethylene and H{sub 2} than without H{sub 2}. These results provide evidence of the importance of the cooperation of the Al{sup 3+} sites in the zeolite and the H{sub 2} in the feed for the genesis of the catalytically active species. The results presented here demonstrate the usefulness of dealuminated zeolite Y as a nearly uniform support that allows precise synthesis of supported catalysts and detailed elucidation of their structures.

  1. Investigation of Zeolite Nucleation and Growth Using NMR Spectroscopy 

    E-print Network

    Rivas Cardona, Alejandra

    2012-02-14

    Zeolite nucleation and growth is a complex problem that has been widely investigated but still not completely understood. However, a full understanding of this process is required in order to develop predictive models for ...

  2. Oxidation of bioethanol using zeolite-encapsulated gold nanoparticles.

    PubMed

    Mielby, Jerrik; Abildstrøm, Jacob Oskar; Wang, Feng; Kasama, Takeshi; Weidenthaler, Claudia; Kegnaes, Søren

    2014-11-10

    With the ongoing developments in biomass conversion, the oxidation of bioethanol to acetaldehyde may become a favorable and green alternative to the preparation from ethylene. Here, a simple and effective method to encapsulate gold nanoparticles in zeolite silicalite-1 is reported and their high activity and selectivity for the catalytic gas-phase oxidation of ethanol are demonstrated. The zeolites are modified by a recrystallization process, which creates intraparticle voids and mesopores that facilitate the formation of small and disperse nanoparticles upon simple impregnation. The individual zeolite crystals comprise a broad range of mesopores and contain up to several hundred gold nanoparticles with a diameter of 2-3?nm that are distributed inside the zeolites rather than on the outer surface. The encapsulated nanoparticles have good stability and result in 50?% conversion of ethanol with 98?% selectivity toward acetaldehyde at 200?°C, which (under the given reaction conditions) corresponds to 606?mol?acetaldehyde/mol?Au?hour(-1) . PMID:25196739

  3. Single and Multiple Heteroatom Incorporation in MFI Zeolites 

    E-print Network

    Garcia Vargas, Nataly

    2012-11-05

    Zeolites are crystalline inorganic solids that are industrially used for adsorption, ion exchange and catalysis. As catalysts, they have been particularly successful in the hydrocarbon processing industry due to their ...

  4. 12. INTERIOR OF BUILDING 2, ORIGINAL ZEOLITE PLANT, AT WEYMOUTH ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    12. INTERIOR OF BUILDING 2, ORIGINAL ZEOLITE PLANT, AT WEYMOUTH LOOKING WEST TO FOUNTAIN. STAIRWAY RUNS DOWN TO FILTRATION BAYS. - F. E. Weymouth Filtration Plant, 700 North Moreno Avenue, La Verne, Los Angeles County, CA

  5. Iba of Zeolites Exchanged with Lithium for Co2 Retention

    NASA Astrophysics Data System (ADS)

    Andrade, E.; Alfaro, S.; Valenzuela, M. A.; Solis, C.; Zaval, E. P.; Rocha, M. F.; Cruz, J.; Pfeiffer, H.; Bosch, P.; Contreras, C.; Baptiste, J.

    2009-03-01

    A great concern on the global climatic change, partially due to industry CO2 expelled to the atmosphere, has motivated the search of new materials able to retain this gas. Clays, perovskites, zeolites and membranes have been utilized to trap the CO2. Zeolites are widely used as molecular sieves in different industrial processes related to gas purification or gas separation. Synthetic zeolites exchanged with lithium were prepared as potential material for CO2 retention. A NRA method using the 7Li (p,?)4He was performed in order to measure the the Li contents. With SEM-EDS the atomic concentrations of elements as C, Na, Si, Al, K, Ca, Fe, etc. were determined. Zeolites were also characterized by XRD.

  6. High adherence copper plating process

    DOEpatents

    Nignardot, Henry (Tesuque, NM)

    1993-01-01

    A process for applying copper to a substrate of aluminum or steel by electrodeposition and for preparing an aluminum or steel substrate for electrodeposition of copper. Practice of the invention provides good adhesion of the copper layer to the substrate.

  7. Lab Tracker and Copper Calculator

    MedlinePLUS

    ... Calculator WDA Publications Copper Connection Newsletter Stories Lab Tracker and Copper Calculator Serum Copper (mcg/dl) Ceruloplasmin ( ... Schilsky, we are pleased to offer the Lab Tracker in two convenient formats. We recommend that you ...

  8. Commander Bowersox Tends to Zeolite Crystal Samples Aboard Space Station

    NASA Technical Reports Server (NTRS)

    2003-01-01

    Expedition Six Commander Ken Bowersox spins Zeolite Crystal Growth sample tubes to eliminate bubbles that could affect crystal formation in preparation of a 15 day experiment aboard the International Space Station (ISS). Zeolites are hard as rock, yet are able to absorb liquids and gases like a sponge. By using the ISS microgravity environment to grow better, larger crystals, NASA and its commercial partners hope to improve petroleum manufacturing and other processes.

  9. Achievement of Bulky Homochirality in Zeolitic Imidazolate-Related Frameworks.

    PubMed

    Wang, Fei; Tang, Yu-Huan; Zhang, Jian

    2015-12-01

    Before this work, adding chiral C centers into zeolitic imidazolate frameworks (ZIFs) has never been realized. Presented here are the first examples on achieving bulky homochirality in ZIF systems, and three homochiral zeolitic imidazolate-related frameworks with sodalite and dia topologies are successfully synthesized by employing enantiopure imidazolate derivatives. The results open a new blueprint on the synthetic design of homochiral ZIFs for future applications. PMID:26558292

  10. Following the movement of Cu ions in a SSZ-13 zeolite during dehydration, reduction and adsorption: a combined in situ TP-XRD, XANES/DRIFTS study

    SciTech Connect

    Kwak, Ja Hun; Varga, Tamas; Peden, Charles HF; Gao, Feng; Hanson, Jonathan C.; Szanyi, Janos

    2014-05-05

    Cu-SSZ-13 has been shown to possess high activity and superior N2 formation selectivity in the selective catalytic reduction of NOx under oxygen rich conditions. Here, a combination of synchrotron-based (XRD and XANES) and vibrational (DRIFTS) spectroscopy tools have been used to follow the changes in the location and coordination environment of copper ions in a Cu-SSZ-13 zeolite during calcinations, reduction with CO, and adsorption of CO and H2O. XANES spectra collected during these procedures provides critical information not only on the variation in the oxidation state of the copper species in the zeolite structure, but also on the changes in the coordination environment around these ions as they interact with the framework, and with different adsorbates (H2O and CO). Time-resolved XRD data indicate the movement of copper ions and the consequent variation of the unit cell parameters during dehydration. DRIFT spectra provide information about the adsorbed species present in the zeolite, as well as the oxidation states of and coordination environment around the copper ions. A careful analysis of the asymmetric T-O-T vibrations of the CHA framework perturbed by copper ions in different coordination environments proved to be especially informative. The results of this study will aid the identification of the location, coordination and oxidation states of copper ions obtained during in operando catalytic studies. Financial support was provided by the US Department of Energy (DOE), Office of Energy Efficiency and Renewable Energy, Vehicle Technologies Program. Part of this work (sample preparation) was performed in the Environmental Molecular Sciences Laboratory (EMSL) at Pacific Northwest National Laboratory (PNNL). The EMSL is a national scientific user facility supported by the US DOE, Office of Biological and Environmental Research. PNNL is a multi-program national laboratory operated for the US DOE by Battelle. All of the spectroscopy work reported here was carried out at the National Synchrotron Light Source (NSLS) at Brookhaven National Laboratory (BNL). NSLS is a national scientific user facility supported by the US DOE.

  11. Characterization of Chemical Properties, Unit Cell Parameters and Particle Size Distribution of Three Zeolite Reference Materials: RM 8850 - Zeolite Y, RM 8851 - Zeolite A and RM 8852 - Ammonium ZSM-5 Zeolite

    SciTech Connect

    Turner,S.; Sieber, J.; Vetter, T.; Zeisler, R.; Marlow, A.; Moreno-Ramirez, M.; Davis, M.; Kennedy, G.; Borghard, W.; et al

    2008-01-01

    Zeolites have important industrial applications including use as catalysts, molecular sieves and ion exchange materials. In this study, three zeolite materials have been characterized by the National Institute of Standards and Technology (NIST) as reference materials (RMs): zeolite Y (RM 8850), zeolite A (RM 8851) and ZSM-5 zeolite (RM 8852). They have been characterized by a variety of chemical and physical measurement methods: X-ray fluorescence (XRF), gravimetry, instrumental neutron activation analysis (INAA), nuclear magnetic resonance (NMR), calorimetry, synchrotron X-ray diffraction, neutron diffraction, laser light extinction, laser light scattering, electric sensing zone, X-ray sedimentation, scanning transmission electron microscopy (STEM), scanning electron microscopy (SEM) and optical microscopy. The chemical homogeneity of the materials has been characterized. Reference values are given for the major components (major elements, loss on ignition [LOI] and loss on fusion [LOF]), trace elements and Si/Al and Na/Al ratios. Information values are given for enthalpies of formation, unit cell parameters, particle size distributions, refractive indices and variation of mass with variation in relative humidity (RH). Comparisons are made to literature unit cell parameters. The RMs are expected to provide a basis for intercomparison studies of these zeolite materials.

  12. Nanocellulose-Zeolite Composite Films for Odor Elimination.

    PubMed

    Keshavarzi, Neda; Mashayekhy Rad, Farshid; Mace, Amber; Ansari, Farhan; Akhtar, Farid; Nilsson, Ulrika; Berglund, Lars; Bergström, Lennart

    2015-07-01

    Free standing and strong odor-removing composite films of cellulose nanofibrils (CNF) with a high content of nanoporous zeolite adsorbents have been colloidally processed. Thermogravimetric desorption analysis (TGA) and infrared spectroscopy combined with computational simulations showed that commercially available silicalite-1 and ZSM-5 have a high affinity and uptake of volatile odors like ethanethiol and propanethiol, also in the presence of water. The simulations showed that propanethiol has a higher affinity, up to 16%, to the two zeolites compared with ethanethiol. Highly flexible and strong free-standing zeolite-CNF films with an adsorbent loading of 89 w/w% have been produced by Ca-induced gelation and vacuum filtration. The CNF-network controls the strength of the composite films and 100 ?m thick zeolite-CNF films with a CNF content of less than 10 vol % displayed a tensile strength approaching 10 MPa. Headspace solid phase microextraction (SPME) coupled to gas chromatography-mass spectroscopy (GC/MS) analysis showed that the CNF-zeolite films can eliminate the volatile thiol-based odors to concentrations below the detection ability of the human olfactory system. Odor removing zeolite-cellulose nanofibril films could enable improved transport and storage of fruits and vegetables rich in odors, for example, onion and the tasty but foul-smelling South-East Asian Durian fruit. PMID:26061093

  13. An analysis of commerical zeolite catalysts by multinuclear NMR

    SciTech Connect

    Flanagan, L.

    1990-09-21

    This work involves studying two commercial hydrocracking catalysts by solid state multinuclear NMR silicon 29 and aluminum 27 with the goal of developing a method of determining the fraction zeolite in the catalysts. The zeolite fraction is known to be one of the faujasite zeolites type X or Y. The clay matrix of the catalyst is assumed to be kaolinite. Fresh, air-exposed commercial hydrocracking catalysts were provided by Phillips Petroleum. Sample 33351-86 was known to be a physical mixture of a Y zeolite and a clay matrix. The other catalyst, 33351-20, was composed of a faujasite zeolite grown within a clay matrix. Both were suspected of being about 20 wt % zeolite. Nothing is known about the state of pretreatment or cation exchange. A portion of each catalyst was calcined in a porcelain crucible in air at 500{degree}C for two hours with a hour heating ramp preceding and a two hour cooling ramp following calcination. 64 refs., 21 figs., 8 tabs.

  14. Inhibition of palm oil oxidation by zeolite nanocrystals.

    PubMed

    Tan, Kok-Hou; Awala, Hussein; Mukti, Rino R; Wong, Ka-Lun; Rigaud, Baptiste; Ling, Tau Chuan; Aleksandrov, Hristiyan A; Koleva, Iskra Z; Vayssilov, Georgi N; Mintova, Svetlana; Ng, Eng-Poh

    2015-05-13

    The efficiency of zeolite X nanocrystals (FAU-type framework structure) containing different extra-framework cations (Li(+), Na(+), K(+), and Ca(2+)) in slowing the thermal oxidation of palm oil is reported. The oxidation study of palm oil is conducted in the presence of zeolite nanocrystals (0.5 wt %) at 150 °C. Several characterization techniques such as visual analysis, colorimetry, rheometry, total acid number (TAN), FT-IR spectroscopy, (1)H NMR spectroscopy, and Karl Fischer analyses are applied to follow the oxidative evolution of the oil. It was found that zeolite nanocrystals decelerate the oxidation of palm oil through stabilization of hydroperoxides, which are the primary oxidation product, and concurrently via adsorption of the secondary oxidation products (alcohols, aldehydes, ketones, carboxylic acids, and esters). In addition to the experimental results, periodic density functional theory (DFT) calculations are performed to elucidate further the oxidation process of the palm oil in the presence of zeolite nanocrystals. The DFT calculations show that the metal complexes formed with peroxides are more stable than the complexes with alkenes with the same ions. The peroxides captured in the zeolite X nanocrystals consequently decelerate further oxidation toward formation of acids. Unlike the monovalent alkali metal cations in the zeolite X nanocrystals (K(+), Na(+), and Li(+)), Ca(2+) reduced the acidity of the oil by neutralizing the acidic carboxylate compounds to COO(-)(Ca(2+))1/2 species. PMID:25897618

  15. Nanosized zeolites as a perspective material for conductometric biosensors creation

    NASA Astrophysics Data System (ADS)

    Kucherenko, Ivan; Soldatkin, Oleksandr; Kasap, Berna Ozansoy; Kirdeciler, Salih Kaan; Kurc, Burcu Akata; Jaffrezic-Renault, Nicole; Soldatkin, Alexei; Lagarde, Florence; Dzyadevych, Sergei

    2015-05-01

    In this work, the method of enzyme adsorption on different zeolites and mesoporous silica spheres (MSS) was investigated for the creation of conductometric biosensors. The conductometric transducers consisted of gold interdigitated electrodes were placed on the ceramic support. The transducers were modified with zeolites and MSS, and then the enzymes were adsorbed on the transducer surface. Different methods of zeolite attachment to the transducer surface were used; drop coating with heating to 200°C turned out to be the best one. Nanozeolites beta and L, zeolite L, MSS, and silicalite-1 (80 to 450 nm) were tested as the adsorbents for enzyme urease. The biosensors with all tested particles except zeolite L had good analytical characteristics. Silicalite-1 (450 nm) was also used for adsorption of glucose oxidase, acetylcholinesterase, and butyrylcholinesterase. The glucose and acetylcholine biosensors were successfully created, whereas butyrylcholinesterase was not adsorbed on silicalite-1. The enzyme adsorption on zeolites and MSS is simple, quick, well reproducible, does not require use of toxic compounds, and therefore can be recommended for the development of biosensors when these advantages are especially important.

  16. Tailoring and visualizing the pore architecture of hierarchical zeolites.

    PubMed

    Wei, Ying; Parmentier, Tanja E; de Jong, Krijn P; Ze?evi?, Jovana

    2015-10-21

    Recently the concept of hierarchical zeolites invoked more explicit attention to enhanced accessibility of zeolites. By realizing additional meso-/macroporosity with the intrinsic microporosity of zeolites, a hierarchical pore system arises which facilitates mass transport while maintaining the zeolite shape selectivity. A great number of synthesis strategies have been developed for tailoring the pore architecture of hierarchical zeolites. In this review, we give a general overview of different synthesis methods for introduction of additional porosity. Advantages and limitations of these different synthesis approaches are addressed. The assessment of pore structure is essential to build the link between the zeolite pore structure and its functionality. A variety of 2D and 3D microscopy techniques are crucial to visualize the hierarchical pore structure, providing unique and comprehensive information that, however, should be linked to the results of bulk characterization techniques as much as possible. The microscopy techniques are classified and discussed according to the different probes used, such as optical light, X-rays and electrons. Representative work is reviewed to elucidate the capability of each technique and their drawbacks. PMID:26007224

  17. Removal of ammonium from municipal landfill leachate using natural zeolites.

    PubMed

    Ye, Zhihong; Wang, Jiawen; Sun, Lingyu; Zhang, Daobin; Zhang, Hui

    2015-12-01

    Ammonium ion-exchange performance of the natural zeolite was investigated in both batch and column studies. The effects of zeolite dosage, contact time, stirring speed and pH on ammonium removal were investigated in batch experiments. The result showed that ammonium removal efficiency increased with an increase in zeolite dosage from 25 to 150 g/L, and an increase in stirring speed from 200 to 250 r/min. But further increase in zeolite dosage and stirring speed would result in an unpronounced increase of ammonium removal. The optimal pH for the removal of ammonium was found as 7.1. In the column studies, the effect of flow rate was investigated, and the total ammonium removal percentage during 180 min operation time decreased with the flow rate though the ion-exchange capacity varied to a very small extent with the flow rate ranging from 4 to 9 mL/min. The spent zeolite was regenerated by sodium chloride solution and the ammonia removal capacity of zeolite changed little or even increased after three regeneration cycles. PMID:26510611

  18. Zeolite synthesis from fly ash and cement kiln dust

    SciTech Connect

    Grutzeck, M.W.

    1996-12-31

    Zeolites added to portland cement paste normally undergo a pozzolanic reaction. However, if the composition of the cement is modified by blending it with fly ash, the calcium silicate hydrate (C-S-H) that forms has a low CaO/SiO{sub 2} ratio which allows it to coexist with a zeolite. In fact, if one adds alkali to the system, it then becomes possible to nucleate and grow a zeolitic phase with C-S-H. Normally zeolites that form from fly ash and NaOH include NaP-1 and analcime. But when the fly ash and NaOH are mixed with cement kiln dust, cancrinite-like phases and tobermorite form instead. This implies that a zeolite-containing monolith could be produced that would exhibit both the cation-exchange and adsorptive properties of zeolites while retaining the characteristic strength and ease of use attributable to cement based materials. These composites show promise as a new class of inexpensive cation exchange and/or chemical adsorbents that can be used for large scale applications.

  19. Solvent Evaporation Assisted Preparation of Oriented Nanocrystalline Mesoporous MFI Zeolites

    SciTech Connect

    Zhu, Kake; Sun, Junming; Liu, Jun; Wang, Li Q.; Wan, Haiying; Hu, Jian Z.; Wang, Yong; Peden, Charles HF; Nie, Zimin

    2011-07-01

    A solvent evaporation route to produce hierarchically porous zeolites with an oriented MFI nanocrystalline structure has been developed, and the method is scalable and productive. In this method, hexadecyltrimethoxysilane is added to an ethanol solution containing zeolitic precursors. A hard gel is formed during the evaporation process. Subsequent hydrothermal treatments produce the hierarchically porous zeolite. High resolution transmission electron microscopy (HRTEM) studies suggest that misoriented zeolite nuclei are produced in the very early stages of the hydrothermal treatment, but further reactions lead to single crystal-like aggregates composed of intergrowth nanocrystals with a mean interparticle pore diameter of 12 nm. All Al atoms exist in tetrahedral sites, as confirmed by 27Al magic angle spinning nuclear magnetic resonance (MAS NMR). Variable temperature hyperpolarized (HP) 129Xe NMR spectroscopy suggest a fast molecular diffusion process from the interconnection between micro- and mesopores. Catalytic conversion of acetone to the isobutene reactions show comparable (with respect to conventional zeolites) selectivity to isobutene. However, hierarchically porous zeolites display enhanced activity and durability because of the more accessible acidic sites in the hierarchically porous structures.

  20. Improved Electroformed Structural Copper and Copper Alloys

    NASA Technical Reports Server (NTRS)

    Malone, G. A.; Hudson, W.; Babcock, B.; Edwards, R.

    1998-01-01

    Electroforming offers a superior means for fabricating internally cooled heat exchangers and structures subjected to thermal environments. Copper is deposited from many such applications because of the good thermal conductivity. It suffers from mediocre yield strength as a structural material and loses mechanical strength at intermediate temperatures. Mechanical properties similar to those of electroformed nickel are desired. Phase 1 examined innovative means to improve deposited copper structural performance. Yield strengths as high as 483 MPa (70 ksi) were obtained with useful ductility while retaining a high level of purity essential to good thermal conductivity. Phase 2 represents a program to explore new additive combinations in copper electrolytes to produce a more fine, equiaxed grain which can be thermally stabilized by other techniques such as alloying in modest degrees and dispersion strengthening. Evaluation of new technology - such as the codeposition of fullerness (diamond-like) particles were made to enhance thermal conductivity in low alloys. A test fire quality tube-bundle engine was fabricated using these copper property improvement concepts to show the superiority of the new coppers and fabrications methods over competitive technologies such as brazing and plasma deposition.

  1. Copper Delivery by Metallochaperone Proteins

    SciTech Connect

    Rosenzweig, A.C.

    2010-03-08

    Copper is an essential element in all living organisms, serving as a cofactor for many important proteins and enzymes. Metallochaperone proteins deliver copper ions to specific physiological partners by direct protein-protein interactions. The Atx1-like chaperones transfer copper to intracellular copper transporters, and the CCS chaperones shuttle copper to copper,zinc superoxide dismutase. Crystallographic studies of these two copper chaperone families have provided insights into metal binding and target recognition by metallochaperones and have led to detailed molecular models for the copper transfer mechanism.

  2. COPPER RESEARCH UPDATE

    EPA Science Inventory

    This presentation provides an update and overview of new research results and remaining research needs with respect to copper corrosion control issues. The topics to be covered include: occurrence of elevated copper release in systems that meet the Action Level; impact of water c...

  3. Preparation of zeolite NaA for CO2 capture from nickel laterite residue

    NASA Astrophysics Data System (ADS)

    Du, Tao; Liu, Li-ying; Xiao, Penny; Che, Shuai; Wang, He-ming

    2014-08-01

    Zeolite NaA was successfully prepared from nickel laterite residue for the first time via a fusion-hydrothermal procedure. The structure and morphology of the as-synthesized zeolite NaA were characterized with a range of experimental techniques, such as X-ray diffraction, scanning electronic microscopy, and infrared spectroscopy. It was revealed that the structures of the produced zeolites were dependent on the molar ratios of the reactants and hydrothermal reaction conditions, so the synthesis conditions were optimized to obtain pure zeolite NaA. Adsorption of nitrogen and carbon dioxide on the prepared zeolite NaA was also measured and analyzed. The results showed that zeolite NaA could be prepared with reasonable purity, it had physicochemical properties comparable with zeolite NaA made from other methods, and it had excellent gas adsorption properties, thus demonstrating that zeolite NaA could be prepared from nickel laterite residue.

  4. Study of pure-silica Zeolite Nucleation and Growth from Solution 

    E-print Network

    Li, Xiang

    2011-10-21

    and direct zeolite nuclei. Unlike many studies performed analyzing the inorganic phase (silica) present in synthesis mixtures, this study quantified the organocation-silica particle interaction and its ultimate effect on zeolite growth mainly through probing...

  5. Interaction of Dimethylmethylphosphonate with Zeolite Y: Impedance-Based Sensor for Detecting Nerve Agent Simulants

    E-print Network

    Dutta, Prabir K.

    sensors.6 At temperatures less than 110 °C, a change in the conductivity of hydrated zeolites is induced control. There are also reports on utilization of zeolites as ionic electrolytes for hydrocarbon sensors

  6. Adsorption and isothermal models of atrazine by zeolite prepared from Egyptian kaolin

    NASA Astrophysics Data System (ADS)

    Jamil, Tarek S.; Gad-Allah, Tarek A.; Ibrahim, Hanan S.; Saleh, Tamer S.

    2011-01-01

    The adsorption behavior of Atrazine on zeolites, prepared from Egyptian kaolin, has been studied in order to consider the application of these types of zeolites in water purification. The batch mode has been employed, using atrazine solution of concentration ranging from 2 to 10 mg /l. The adsorption capacity and distribution coefficients ( Kd) were determined for the adsorption system as a function of sorbate concentration. It was found that, under the studies concentrations, the percent of adsorbed atrazine on both zeolites match to Langmuir and Freundlich adsorption models. The constants of each model were calculated to assess the adsorption behavior of atrazine on each type of zeolite. According to the equilibrium studies, adsorption of atrazine on zeolite X at lower concentrations is much better than that on zeolite A. The application of Dublin-Kaganer-Radushkevich model revealed physisorption endothermic adsorption process for both zeolites. These results show that natural zeolites hold great potential to remove hazardous materials such as atrazine from water.

  7. The use Na, Li, K cations for modification of ZSM-5 zewolite to control hydrocarbon cold-start emission

    SciTech Connect

    Golubeva V.; Rohatgi U.; Korableva, A.; Anischenko, O.; Kustov, L.; Nissenbaum, V; Viola, M.B.

    2012-08-29

    This paper addresses the problem of controlling hydrocarbon emissions from cold-start of engines by investigating the adsorbents which could adsorb the hydrocarbons at cold temperatures and hold them to 250-300 ?. The materials, that has been studied, are based on the modification of ZSM-5 (SiO{sub 2}/Al{sub 2}O{sub 3} = 35) zeolite with Li, K, Na cations. It has been shown that the introduction of Li, Na and K in an amount that is equivalent to the content of Al in zeolite results in occurrence of toluene temperature desorption peaks at high-temperatures. The toluene temperature desorption curves for 5%Li-ZSM-5 and 2.3%Na-ZSM-5 zeolites are identical and have peak toluene desorption rate between 200 to 400 ?. Upon analysis of toluene adsorption isotherms for 2.3%Na-ZSM-5 and 5%Li-ZSM-5, it was concluded that the toluene diffusion inside of the modified zeolites channels is extremely slow and the sorption capacity of 2.3%Na-ZSM-5 is higher than with 5%Li-ZSM-5. The 2.3%Na-ZSM-5 didn't change toluene temperature programmed desorption (TPD) rate of curve after the treatment in environment with 10% ?{sub 2}? at 750-800 ? for about 28 h. The 2.3%Na-ZSM-5 zeolite is very promising as adsorbent to control the cold-start hydrocarbon emissions.

  8. One-pot synthesis of hierarchical FeZSM-5 zeolites from natural aluminosilicates for selective catalytic reduction of NO by NH3.

    PubMed

    Yue, Yuanyuan; Liu, Haiyan; Yuan, Pei; Yu, Chengzhong; Bao, Xiaojun

    2015-01-01

    Iron-modified ZSM-5 zeolites (FeZSM-5s) have been considered to be a promising catalyst system to reduce nitrogen oxide emissions, one of the most important global environmental issues, but their synthesis faces enormous economic and environmental challenges. Herein we report a cheap and green strategy to fabricate hierarchical FeZSM-5 zeolites from natural aluminosilicate minerals via a nanoscale depolymerization-reorganization method. Our strategy is featured by neither using any aluminum-, silicon-, or iron-containing inorganic chemical nor involving any mesoscale template and any post-synthetic modification. Compared with the conventional FeZSM-5 synthesized from inorganic chemicals with the similar Fe content, the resulting hierarchical FeZSM-5 with highly-dispersed iron species showed superior catalytic activity in the selective catalytic reduction of NO by NH3. PMID:25791958

  9. One-pot synthesis of hierarchical FeZSM-5 zeolites from natural aluminosilicates for selective catalytic reduction of NO by NH3

    PubMed Central

    Yue, Yuanyuan; Liu, Haiyan; Yuan, Pei; Yu, Chengzhong; Bao, Xiaojun

    2015-01-01

    Iron-modified ZSM-5 zeolites (FeZSM-5s) have been considered to be a promising catalyst system to reduce nitrogen oxide emissions, one of the most important global environmental issues, but their synthesis faces enormous economic and environmental challenges. Herein we report a cheap and green strategy to fabricate hierarchical FeZSM-5 zeolites from natural aluminosilicate minerals via a nanoscale depolymerization-reorganization method. Our strategy is featured by neither using any aluminum-, silicon-, or iron-containing inorganic chemical nor involving any mesoscale template and any post-synthetic modification. Compared with the conventional FeZSM-5 synthesized from inorganic chemicals with the similar Fe content, the resulting hierarchical FeZSM-5 with highly-dispersed iron species showed superior catalytic activity in the selective catalytic reduction of NO by NH3. PMID:25791958

  10. One-pot synthesis of hierarchical FeZSM-5 zeolites from natural aluminosilicates for selective catalytic reduction of NO by NH3

    NASA Astrophysics Data System (ADS)

    Yue, Yuanyuan; Liu, Haiyan; Yuan, Pei; Yu, Chengzhong; Bao, Xiaojun

    2015-03-01

    Iron-modified ZSM-5 zeolites (FeZSM-5s) have been considered to be a promising catalyst system to reduce nitrogen oxide emissions, one of the most important global environmental issues, but their synthesis faces enormous economic and environmental challenges. Herein we report a cheap and green strategy to fabricate hierarchical FeZSM-5 zeolites from natural aluminosilicate minerals via a nanoscale depolymerization-reorganization method. Our strategy is featured by neither using any aluminum-, silicon-, or iron-containing inorganic chemical nor involving any mesoscale template and any post-synthetic modification. Compared with the conventional FeZSM-5 synthesized from inorganic chemicals with the similar Fe content, the resulting hierarchical FeZSM-5 with highly-dispersed iron species showed superior catalytic activity in the selective catalytic reduction of NO by NH3.

  11. Bioaccessibility and Solubility of Copper in Copper-Treated Lumber

    EPA Science Inventory

    Micronized copper (MC)-treated lumber is a recent replacement for Chromated Copper Arsenate (CCA) and Ammonium Copper (AC)-treated lumbers; though little is known about the potential risk of copper (Cu) exposure from incidental ingestion of MC-treated wood. The bioaccessibility o...

  12. Fabrication of high wettability gradient on copper substrate

    NASA Astrophysics Data System (ADS)

    Huang, Ding-Jun; Leu, Tzong-Shyng

    2013-09-01

    Copper is one of the most widely used materials in condensation heat transfer. Recently there has been great interest in improving the condensation heat transfer efficiency through copper surface modification. In this study, we describe the fabrication processes of how copper surfaces were modified to be superhydrophilic (CA ? 10°) and superhydrophobic (CA > 150°) by means of H2O2 immersion and fluorination with Teflon. The wettability gradient of copper surfaces with contact angles (CA) changing from superhydrophilic to superhydrophobic are also demonstrated. Unlike previous studies on gradient surfaces in which the wettability gradient is controlled either non-precisely or entirely uncontrolled, in this study, the contact angles along wettability gradient copper surfaces vary with a precisely designed gradient. It is demonstrated that a high wettability gradient copper surface can be successfully fabricated using photolithography to define the area ratios between superhydrophilic and superhydrophobic patterns within a short distance. The fabricated wettability gradient of copper surfaces is expected to be able to enhance the condensation heat transfer efficiency.

  13. Introducing copper phthalocyanine as a qubit

    NASA Astrophysics Data System (ADS)

    Warner, Marc; Din, Salahud; Gardener, Jules; Morley, Gavin W.; Wu, Wei; Stoneham, Marshall; Fisher, Andrew J.; Heutz, Sandrine; Kay, Christopher W. M.; Aeppli, Gabriel

    2012-02-01

    Quantum information processing (QIP) has been shown to solve certain useful problems faster than its classical counterpart. However finding a physical system upon which to execute these algorithms is a challenging task. One promising implementation is to use an electron spin in a magnetic field as the information bearing quantum system. Numerous options have been proposed along these lines. Here I discuss a new candidate qubit, copper phthalocyanine. The copper atom at the centre of the molecule carries an unpaired electron. Pulsed electron paramagnetic resonance measurements of relaxation times reveal that it has potential for QIP. We measure the spin-lattice and spin-spin relaxation times of this electron and demonstrate single qubit manipulations. Solid-state electronic devices can be built with this low cost material, which is optically active, and offers great opportunities for chemical and physical modification, leading to significant control of magnetic and other properties.

  14. Highly dispersed metal atoms in zeolites. Progress report. [Hydroformylation

    SciTech Connect

    Suib, S.L.

    1985-04-15

    Our studies this past year have involved work in the following areas: preparation of highly dispersed metal atoms in molecular sieves via microwave discharge methods, hydroformylation of l-pentene with rhodium zeolites and Rutherford backscattering studies of zeolites. The microwave discharge method has been developed by us to provide a synthetic route to produce highly dispersed iron and cobalt atom clusters in several molecular sieves such as zeolites, aluminophosphates, pillared clays and clays. We have done ferromagnetic resonance, infrared, Mossbauer and scanning electron microscopy experiments on these materials. Generalizations that can be made so far are that these particles are extremely small, reactive and their formation is governed by the type of support. They are all active in Fischer-Tropsch reactions although cobalt materials are more selective and stable than iron materials. Superparamagnetic iron clusters have been observed for the incorporation of iron into zeolites, ALPO's and pillared clays. These results are unique in that iron (0) is usually oxidized in a zeolite environment. The second project deals with Wilkinson's catalyst and the preparation of phosphine rhodium zeolite catalysts. These catalysts are selective towards aldehyde formation and the normal to branched aldehyde ratio can be controlled. EXAFS, Fourier transform infrared and x-ray powder diffraction experiments have been carried out on these catalysts. The third project deals with Rutherford backscattering studies of zeolites. We have shown that Rutherford backscattering methods can be used to distinguish metal ions on the surface of a porous support from internal metal ions exchanged into the pores of the support.

  15. Synthesis of mesoporous zeolite single crystals with cheap porogens

    SciTech Connect

    Tao Haixiang; Li Changlin; Ren Jiawen; Wang Yanqin; Lu Guanzhong

    2011-07-15

    Mesoporous zeolite (silicalite-1, ZSM-5, TS-1) single crystals have been successfully synthesized by adding soluble starch or sodium carboxymethyl cellulose (CMC) to a conventional zeolite synthesis system. The obtained samples were characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM), transmission electron microscopy (TEM), nitrogen sorption analysis, {sup 27}Al magic angle spinning nuclear magnetic resonance ({sup 27}Al MAS NMR), temperature-programmed desorption of ammonia (NH{sub 3}-TPD) and ultraviolet-visible spectroscopy (UV-vis). The SEM images clearly show that all zeolite crystals possess the similar morphology with particle size of about 300 nm, the TEM images reveal that irregular intracrystal pores are randomly distributed in the whole crystal. {sup 27}Al MAS NMR spectra indicate that nearly all of the Al atoms are in tetrahedral co-ordination in ZSM-5, UV-vis spectra confirm that nearly all of titanium atoms are incorporated into the framework of TS-1. The catalytic activity of meso-ZSM-5 in acetalization of cyclohexanone and meso-TS-1 in hydroxylation of phenol was also studied. The synthesis method reported in this paper is cost-effective and environmental friendly, can be easily expended to prepare other hierarchical structured zeolites. - Graphical abstract: Mesoporous zeolite single crystals were synthesized by using cheap porogens as template. Highlights: > Mesoporous zeolite (silicalite-1, ZSM-5, TS-1) single crystals were synthesized. > Soluble starch or sodium carboxymethyl cellulose (CMC) was used as porogens. > The mesoporous zeolites had connected mesopores although closed pores existed. > Higher catalytic activities were obtained.

  16. Toward a Database of Hypothetical Zeolite Structures David J. Earl, and Michael W. Deem*,

    E-print Network

    Earl, David J.

    Toward a Database of Hypothetical Zeolite Structures David J. Earl, and Michael W. Deem the sampling. We discuss construction of a database of hypothetical zeolite frameworks with this approach and discuss how the database may be used to search for new zeolite structures with specific material

  17. Ion exchange of zeolite membranes by a vacuum `flow-through' Seok-Jhin Kim a

    E-print Network

    Nair, Sankar

    Ion exchange of zeolite membranes by a vacuum `flow-through' technique Seok-Jhin Kim October 2014 Keywords: Ion exchange Zeolite membrane Flow-through technique Separation Catalysis a b s t r a c t Ion exchange of nanoporous (e.g., zeolite) membranes is of increasing importance

  18. Molecular simulations of hydrogen and methane permeation through pore mouth modified zeolite Sang Eun Jeea

    E-print Network

    McGaughey, Alan

    Molecular simulations of hydrogen and methane permeation through pore mouth modified zeolite zeolite membranes whose pore mouths have been chemically modified. An important challenge for materials the hydrogen flux possible with an unmodified zeolite membrane. Motivated by this, the effect of the pore mouth

  19. Framework Stabilization of Si-Rich LTA Zeolite Prepared in Organic-Free Media

    SciTech Connect

    Conato, Marlon T.; Oleksiak, Matthew D.; McGrail, B. Peter; Motkuri, Radha K.; Rimer, Jeffrey D.

    2014-10-16

    Zeolite HOU-2 (LTA type) is prepared with the highest silica content (Si/Al = 2.1) reported for Na-LTA zeolites without the use of an organic structure-directing agent. The rational design of Si-rich zeolites has the potential to improve their thermal stability for applications in catalysis, gas storage, and selective separations.

  20. UTILITY OF SYNTHETIC ZEOLITES IN REMOVAL OF INORGANIC AND ORGANIC WATER POLLUTANTS

    EPA Science Inventory

    Zeolites are well known for their ion exchange and adsorption properties. Different inorganic and organic pollutants have been removed from water at room temperature using various zeolites. Synthetic zeolites like ZSM-5, Ferrierite, Beta and Faujasite Y have been used to remove i...

  1. Properties of Zeolite A Obtained from Powdered Laundry Detergent: An Undergraduate Experiment.

    ERIC Educational Resources Information Center

    Smoot, Alison L.; Lindquist, David A.

    1997-01-01

    Presents experiments that introduce students to the myriad properties of zeolites using the sodium form of zeolite A (Na-A) from laundry detergent. Experiments include extracting Na-A from detergent, water softening properties, desiccant properties, ion-exchange properties, and Zeolite HA as a dehydration catalyst. (JRH)

  2. Zeolite-Mediated Photochemical Charge Separation Using a Surface-Entrapped Ruthenium-Polypyridyl Complex

    E-print Network

    Dutta, Prabir K.

    Zeolite-Mediated Photochemical Charge Separation Using a Surface-Entrapped Ruthenium)ethenyl]benzene (L), a polypyridyl complex of ruthenium(II) was tethered on the surface of zeolite Y. Electrochemical photolysis of the ruthenium-zeolite solid ion-exchanged with diquat and suspended in a propyl viologen

  3. ZEOLITE PERFORMANCE AS AN ANION EXCHANGER FOR ARSENIC SEQUESTRATION IN WATER

    EPA Science Inventory

    Zeolites are well known for their use in ion exchange and acid catalysis reactions. The use of zeolites in anion or ligand exchange reactions is less studied. The NH4+ form of zeolite Y (NY6, Faujasite) has been tested in this work to evaluate its performance for arsenic removal...

  4. Algebraic Description of Coordination Sequences and Exact Topological Densities for Zeolites

    E-print Network

    Sloane, Neil J. A.

    Algebraic Description of Coordination Sequences and Exact Topological Densities for Zeolites R. Although it was known that for many zeolites the terms of the CS grow quadratically with k, no systematic investigation had been carried out. Up to 2000 terms have now been calculated for all the zeolites tabulated

  5. Algebraic Description of Coordination Sequences and Exact Topological Densities for Zeolites

    E-print Network

    Sloane, Neil J. A.

    Algebraic Description of Coordination Sequences and Exact Topological Densities for Zeolites R- dimensional sphere packings. Although was known that for many zeolites the terms the CS grow quadratically with systematic investigation had been carried out. 2000 terms have now been calculated for the zeolites tabulated

  6. Locating stationary points of sorbate-zeolite potential energy surfaces using interval analysis

    E-print Network

    Stadtherr, Mark A.

    Locating stationary points of sorbate-zeolite potential energy surfaces using interval analysis in a zeolite can be studied using transition-state theory. In this application, and other applications points, transition states, zeolites, diffusion, interval-Newton method Author to whom all correspondence

  7. Materials Chemistry and Physics 83 (2004) 8995 Microwave preparation of Li-zeolite directly from

    E-print Network

    Gulari, Erdogan

    2004-01-01

    Materials Chemistry and Physics 83 (2004) 89­95 Microwave preparation of Li-zeolite directly from in revised form 3 September 2003; accepted 12 September 2003 Abstract Li-zeolites were successfully and lithium hydroxide as the hydrolytic agent. Many types of Li-zeolites were obtained by controlling

  8. Researchers are developing novel zeolite-based materials with 1-D nanopores for automotive applications.

    E-print Network

    Bustamante, Fabián E.

    Researchers are developing novel zeolite-based materials with 1-D nanopores for automotive its optimal temperature. The HC trap is based upon a special class of zeolites with non with the team led by Dr. Broadbelt in conducting theoretical modeling of zeolites in an effort to improve

  9. COPPER CABLE RECYCLING TECHNOLOGY

    SciTech Connect

    Chelsea Hubbard

    2001-05-01

    The United States Department of Energy (DOE) continually seeks safer and more cost-effective technologies for use in deactivation and decommissioning (D&D) of nuclear facilities. The Deactivation and Decommissioning Focus Area (DDFA) of the DOE's Office of Science and Technology (OST) sponsors large-scale demonstration and deployment projects (LSDDPs). At these LSDDPs, developers and vendors of improved or innovative technologies showcase products that are potentially beneficial to the DOE's projects and to others in the D&D community. Benefits sought include decreased health and safety risks to personnel and the environment, increased productivity, and decreased costs of operation. The Idaho National Engineering and Environmental Laboratory (INEEL) generated a list of statements defining specific needs and problems where improved technology could be incorporated into ongoing D&D tasks. One such need is to reduce the volume of waste copper wire and cable generated by D&D. Deactivation and decommissioning activities of nuclear facilities generates hundreds of tons of contaminated copper cable, which are sent to radioactive waste disposal sites. The Copper Cable Recycling Technology separates the clean copper from contaminated insulation and dust materials in these cables. The recovered copper can then be reclaimed and, more importantly, landfill disposal volumes can be reduced. The existing baseline technology for disposing radioactively contaminated cables is to package the cables in wooden storage boxes and dispose of the cables in radioactive waste disposal sites. The Copper Cable Recycling Technology is applicable to facility decommissioning projects at many Department of Energy (DOE) nuclear facilities and commercial nuclear power plants undergoing decommissioning activities. The INEEL Copper Cable Recycling Technology Demonstration investigated the effectiveness and efficiency to recycle 13.5 tons of copper cable. To determine the effectiveness of separating out radioactive contamination, the copper cable was coated with a surrogate contaminant. The demonstration took place at the Bonneville County Technology Center in Idaho Falls, Idaho.

  10. Fabricating Copper Nanotubes by Electrodeposition

    NASA Technical Reports Server (NTRS)

    Yang, E. H.; Ramsey, Christopher; Bae, Youngsam; Choi, Daniel

    2009-01-01

    Copper tubes having diameters between about 100 and about 200 nm have been fabricated by electrodeposition of copper into the pores of alumina nanopore membranes. Copper nanotubes are under consideration as alternatives to copper nanorods and nanowires for applications involving thermal and/or electrical contacts, wherein the greater specific areas of nanotubes could afford lower effective thermal and/or electrical resistivities. Heretofore, copper nanorods and nanowires have been fabricated by a combination of electrodeposition and a conventional expensive lithographic process. The present electrodeposition-based process for fabricating copper nanotubes costs less and enables production of copper nanotubes at greater rate.

  11. Copper as a biocidal tool.

    PubMed

    Borkow, Gadi; Gabbay, Jeffrey

    2005-01-01

    Copper ions, either alone or in copper complexes, have been used to disinfect liquids, solids and human tissue for centuries. Today copper is used as a water purifier, algaecide, fungicide, nematocide, molluscicide as well as an anti-bacterial and anti-fouling agent. Copper also displays potent anti-viral activity. This article reviews (i) the biocidal properties of copper; (ii) the possible mechanisms by which copper is toxic to microorganisms; and (iii) the systems by which many microorganisms resist high concentrations of heavy metals, with an emphasis on copper. PMID:16101497

  12. Fabrication of zeolite/polymer multilayer composite membranes for carbon dioxide capture: Deposition of zeolite particles on polymer supports.

    PubMed

    Ramasubramanian, Kartik; Severance, Michael A; Dutta, Prabir K; Ho, W S Winston

    2015-08-15

    Membranes, due to their smaller footprint and potentially lower energy consumption than the amine process, offer a promising route for post-combustion CO2 capture. Zeolite Y based inorganic selective layers offer a favorable combination of CO2 permeance and CO2/N2 selectivity, membrane properties crucial to the economics. For economic viability on large scale, we propose to use flexible and scalable polymer supports for inorganic selective layers. The work described in this paper developed a detailed protocol for depositing thin zeolite Y seed layers on polymer supports, the first step in the synthesis of a polycrystalline zeolite Y membrane. We also studied the effects of support surface morphology (pore size and surface porosity) on the quality of deposition and identified favorable supports for the deposition. Two different zeolite Y particles with nominal sizes of 200 nm and 40 nm were investigated. To obtain a complete coverage of zeolite particles on the support surface with minimum defects and in a reproducible manner, a vacuum-assisted dip-coating technique was developed. Images obtained using both digital camera and optical microscope showed the presence of color patterns on the deposited surface which suggested that the coverage was complete. Electron microscopy revealed that the particle packing was dense with some drying cracks. Layer thickness with the larger zeolite Y particles was close to 1 ?m while that with the smaller particles was reduced to less than 0.5 ?m. In order to reduce drying cracks for layers with smaller zeolite Y particles, thickness was reduced by lowering the dispersion concentration. Transport measurement was used as an additional technique to characterize these layers. PMID:25950846

  13. SO2 REMOVAL FROM FLUE GASES USING UTILITY SYNTHESIZED ZEOLITES

    SciTech Connect

    MICHAEL GRUTZECK

    1998-10-31

    It is well known that natural and synthetic zeolites (molecular sieves) can adsorb gaseous SO2 from flue gas and do it more efficiently than lime based scrubbing materials. Unfortunately their cost ($500-$800 per ton) has deterred their use in this capacity. It is also known that zeolites are easy to synthesize from a variety of natural and man-made materials. The overall objective of the current work has been to evaluate the feasibility of having a utility synthesize its own zeolites, on-site, from fly ash and other recycled materials and then use these zeolites to adsorb SO2 from their flue gases. Work to date has shown that the efficiency of the capture process is related to the degree of crystallinity and the type of zeolite that forms in the samples. Normally, those samples cured at 150°C contained a greater proportion of zeolite and as such were more SO2 adsorptive than their low-temperature counterparts. However, in order for the project to be successful, on site synthesis must remain an option, i.e. _100°C synthesis. In light of this, the experimental focus now has two aspects. First, compositions of the starting materials are being altered by blending the current suite of fly ashes with other fly ashes, ground glass cullet and silica fume to promote the formation and growth of well crystallized and highly adsorptive zeolites. Second, greater degrees of reaction at significantly lower temperatures are being promote by ball milling the fly ash prior to use, by the use of more concentrated caustic solutions, and by the addition of zeolite seeds to the reactants. In all cases studies will focus on the effect of structure type and degree of conversion on SO2 adsorption. Future work will concentrate on the study of the effect of weathering on the suitability of converting fly ash into zeolites. This is an especially important study, considering the acres of fly ash now in storage throughout the country.

  14. SO2 REMOVAL FROM FLUE GASES USING UTILITY SYNTHESIZED ZEOLITES

    SciTech Connect

    Michael Grutzeck

    1999-04-30

    It is well known that natural and synthetic zeolites (molecular sieves) can adsorb gaseous SO{sub 2} from flue gas and do it more efficiently than lime based scrubbing materials. Unfortunately their cost ($500-$800 per ton) has deterred their use in this capacity. It is also known that zeolites are easy to synthesize from a variety of natural and man-made materials. The overall objective of the current work has been to evaluate the feasibility of having a utility synthesize its own zeolites, on-site, from fly ash and other recycled materials and then use these zeolites to adsorb SO{sub 2} from their flue gases. Work to date has shown that the efficiency of the capture process is related to the degree of crystallinity and the type of zeolite that forms in the samples. Normally, those samples cured at 150 C contained a greater proportion of zeolite and as such were more SO{sub 2} adsorptive than their low-temperature counterparts. However, in order for the project to be successful, on site synthesis must remain an option, i.e. 100 C synthesis. In light of this, the experimental focus now has two aspects. First, compositions of the starting materials are being altered by blending the current suite of fly ashes with ground glass cullet and silica fume to promote the formation and growth of well crystallized and highly adsorptive zeolites. Second, greater degrees of reaction at significantly lower temperatures are being promote by ball milling the fly ash prior to use, by the use of more concentrated caustic solutions, and by the addition of zeolite seeds to the reactants. In all cases studies will focus on the effect of structure type and degree of conversion on SO{sub 2} adsorption. Future work will concentrate on the study of the effect of weathering on the suitability of converting fly ash into zeolites. This is an especially important study, considering the acres of fly ash now in storage throughout the US.

  15. Zeolites for the selective adsorption of sulfur hexafluoride.

    PubMed

    Matito-Martos, I; Álvarez-Ossorio, J; Gutiérrez-Sevillano, J J; Doblaré, M; Martin-Calvo, A; Calero, S

    2015-07-21

    Molecular simulations have been used to investigate at the molecular level the suitability of zeolites with different topology on the adsorption, diffusion and separation of a nitrogen-sulfur hexafluoride mixture containing the latter at low concentration. This mixture represents the best alternative for the sulfur hexafluoride in industry since it reduces the use of this powerful greenhouse gas. A variety of zeolites are tested with the aim to identify the best structure for the recycling of sulfur hexafluoride in order to avoid its emission to the atmosphere and to overcome the experimental difficulties of its handling. Even though all zeolites show preferential adsorption of sulfur hexafluoride, we identified local structural features that reduce the affinity for sulfur hexafluoride in zeolites such as MOR and EON, providing exclusive adsorption sites for nitrogen. Structures such as ASV and FER were initially considered as good candidates based on their adsorption features. However, they were further discarded based on their diffusion properties. Regarding operation conditions for separation, the range of pressure that spans from 3 × 10(2) to 3 × 10(3) kPa was identified as the optimal to obtain the highest adsorption loading and the largest SF6/N2 selectivity. Based on these findings, zeolites BEC, ITR, IWW, and SFG were selected as the most promising materials for this particular separation. PMID:26099734

  16. Cadmium adsorption on vermiculite, zeolite and pumice: batch experimental studies.

    PubMed

    Panuccio, Maria Rosaria; Sorgonà, Agostino; Rizzo, Marcella; Cacco, Giovanni

    2009-01-01

    Batch experiments were performed to evaluate the combined effects of ionic activity, pH, and contact time on the cadmium sorption in three different minerals, vermiculite, zeolite, and pumice, commonly employed as substrata in nurseries and recently considered for their potential use in remediation methods. The extent of cadmium sorption was vermiculite>zeolite>pumice, as shown by the Langmuir and Freundlich parameters, and it was highly dependent on mineral characteristics. The percentage of cadmium sorption in zeolite and vermiculite did not depend on cadmium concentration, while in pumice this percentage was positively correlated to the initial cadmium concentration. At low cadmium concentrations (30-120 microM), the metal sorbed on zeolite was mainly present in the nonexchangeable form (70%) at levels much higher than those found for vermiculite and pumice. The primary variable responsible for determination of cadmium mobility in these minerals was confirmed to be pH. The ionic concentrations of Hoagland nutrient solution were significantly modified by both pH and mineral composition, while the presence of cadmium caused no changes. With vermiculite and zeolite, the time-course of cadmium sorption was related to mineral composition to a greater extent than to cadmium concentration. While with pumice, the percentage of cadmium sorbed after 6 weeks was lower than with the other two minerals, and it was inversely correlated to the initial cadmium concentration. PMID:18082309

  17. Phenol removal from wastewater by adsorption on zeolitic composite.

    PubMed

    Bizerea Spiridon, Otilia; Preda, Elena; Botez, Alexandru; Pitulice, Laura

    2013-09-01

    It is well known that adsorption is an efficient method of removal of various pollutants from wastewater. The present study examines the phenol removal from water by adsorption on a new material, based on zeolitic volcanic tuff. This compound contains zeolitic tuff and cellulose, another known adsorbent, in a mass ratio of 4 to 1. The performances of the new adsorbent composite were compared with those of a widely used adsorbent material, zeolitic volcanic tuff. The adsorbent properties were tested on batch synthetic solutions containing 1-10 mg L(-1) (1-10 ppm) phenol, at room temperature without pH adjustment. The influence of the adsorbent dose, pH and contact time on the removal degree of phenol from water was investigated. The experimental data were modeled using the Langmuir, Freundlich, and Temkin adsorption isotherms. The Langmuir model was found to best represent our data revealing a monolayer adsorption with a maximum adsorption capacity between 0.12 and 0.53 mg g(-1) at 25 °C, for 2.00 g of adsorbent, depending on the initial phenol concentration. The adsorption kinetic study was performed using a pseudo-first- and pseudo-second-order kinetic models illustrating that phenol adsorption on zeolite composite is well described by pseudo-first kinetic equations. Our results indicated that phenol adsorption on the new adsorbent composite is superior to that on the classic zeolite. PMID:23589237

  18. Risk assessment for the transportation of radioactive zeolite liners

    SciTech Connect

    Not Available

    1982-01-01

    The risk is estimated for the shipment of radioactive zeolite liners in support of the Zeolite Vitrification Demonstration Program currently underway at Pacific Northwest Laboratory under the sponsorship of the US Department of Energy. This program will establish the feasibility of zeolite vitrification as an effective means of immobilizing high-specific-activity wastes. In this risk assessment, it is assumed that two zeolite liners, each loaded around July 1, 1981 to 60,000 Ci, will be shipped by truck around January 1, 1982. However, to provide a measure of conservatism, each liner is assumed to initially hole 70,000 Ci, with the major radioisotopes as follow: /sup 90/Sr = 3000 Ci, /sup 134/Cs = 7000 Ci, /sup 137/Cs = 60,000 Ci. Should shipment take place with essentially no delay after initial loading (regardless of loading date), the shipment loading would be only 2.7% higher than that for the assumed six-month delay. This would negligibly affect the overall risk. As a result of this risk assessment, it is concluded that the transport of the radioactive zeolite liners from TMI to PNL by truck can be conducted at an insignificant level of risk to the public.

  19. Targeting copper in cancer therapy: 'Copper That Cancer'.

    PubMed

    Denoyer, Delphine; Masaldan, Shashank; La Fontaine, Sharon; Cater, Michael A

    2015-11-01

    Copper is an essential micronutrient involved in fundamental life processes that are conserved throughout all forms of life. The ability of copper to catalyze oxidation-reduction (redox) reactions, which can inadvertently lead to the production of reactive oxygen species (ROS), necessitates the tight homeostatic regulation of copper within the body. Many cancer types exhibit increased intratumoral copper and/or altered systemic copper distribution. The realization that copper serves as a limiting factor for multiple aspects of tumor progression, including growth, angiogenesis and metastasis, has prompted the development of copper-specific chelators as therapies to inhibit these processes. Another therapeutic approach utilizes specific ionophores that deliver copper to cells to increase intracellular copper levels. The therapeutic window between normal and cancerous cells when intracellular copper is forcibly increased, is the premise for the development of copper-ionophores endowed with anticancer properties. Also under investigation is the use of copper to replace platinum in coordination complexes currently used as mainstream chemotherapies. In comparison to platinum-based drugs, these promising copper coordination complexes may be more potent anticancer agents, with reduced toxicity toward normal cells and they may potentially circumvent the chemoresistance associated with recurrent platinum treatment. In addition, cancerous cells can adapt their copper homeostatic mechanisms to acquire resistance to conventional platinum-based drugs and certain copper coordination complexes can re-sensitize cancer cells to these drugs. This review will outline the biological importance of copper and copper homeostasis in mammalian cells, followed by a discussion of our current understanding of copper dysregulation in cancer, and the recent therapeutic advances using copper coordination complexes as anticancer agents. PMID:26313539

  20. Volatility of copper

    SciTech Connect

    Palmer, D.A.; Simonson, J.M.; Joyce, D.B.

    1996-08-01

    The relevant aqueous thermodynamics of copper and its oxides are evaluated and summarized with emphasis on solubility, hydrolysis, and complexation. The solubilities of metallic copper, solid cuprous and cupric oxides in steam measured by Pocock and Stewart in 1963 are discussed and the latter data are fitted in the form of established empirical equations and compared to other existing results. No other sources of data were found for the solubility of copper and cupric oxide in steam and even these data are very limited. Discussion of corresponding available solubility data on both oxide phases in liquid water is given. The possible effects of complexing agents are considered. A brief discussion is provided of the role of surface adsorption in determining the fate of dissolved copper in the boiler. 37 refs., 5 figs., 3 tabs.

  1. Drinking Water Problems: Copper 

    E-print Network

    Dozier, Monty; McFarland, Mark L.; Lesikar, Bruce J.

    2006-01-25

    an alternative drink- ing-water supply such as bottled water. Treatment options for reducing copper concentrations in water include (1) reverse osmosis, (2) distillation or (3) ion exchange. Reverse osmosis and distillation treatment options typically are point...

  2. Synthesis of chiral polymorph A-enriched zeolite Beta with an extremely concentrated fluoride route

    PubMed Central

    Tong, Mingquan; Zhang, Daliang; Fan, Weibin; Xu, Jun; Zhu, Liangkui; Guo, Wen; Yan, Wenfu; Yu, Jihong; Qiu, Shilun; Wang, Jianguo; Deng, Feng; Xu, Ruren

    2015-01-01

    Chiral zeolitic materials with intrinsically chiral frameworks are highly desired because they can combine both shape selectivity and enantioselectivity. In the field of zeolite, the synthesis of chiral polymorph A of zeolite Beta or chiral polymorph A-enriched zeolite Beta is one of the biggest challenges. We demonstrate here a generalized extremely concentrated fluoride route for the synthesis of chiral polymorph A-enriched zeolite Beta in the presence of five achiral organic structure-directing agents. The polymorph A-enriched Ti-Beta shows a higher enantioselectivity for the asymmetric epoxidation of alkenes than the normal Ti-Beta. PMID:26096214

  3. Synthesis of chiral polymorph A-enriched zeolite Beta with an extremely concentrated fluoride route

    NASA Astrophysics Data System (ADS)

    Tong, Mingquan; Zhang, Daliang; Fan, Weibin; Xu, Jun; Zhu, Liangkui; Guo, Wen; Yan, Wenfu; Yu, Jihong; Qiu, Shilun; Wang, Jianguo; Deng, Feng; Xu, Ruren

    2015-06-01

    Chiral zeolitic materials with intrinsically chiral frameworks are highly desired because they can combine both shape selectivity and enantioselectivity. In the field of zeolite, the synthesis of chiral polymorph A of zeolite Beta or chiral polymorph A-enriched zeolite Beta is one of the biggest challenges. We demonstrate here a generalized extremely concentrated fluoride route for the synthesis of chiral polymorph A-enriched zeolite Beta in the presence of five achiral organic structure-directing agents. The polymorph A-enriched Ti-Beta shows a higher enantioselectivity for the asymmetric epoxidation of alkenes than the normal Ti-Beta.

  4. Nondestructive depth profiling of rare-earth and actinide zeolites via Rutherford backscattering methods

    SciTech Connect

    Baumann, S.A.; Strathman, M.D.; Suib, S.L.

    1988-05-15

    Rutherford backscattering (RBS) methods have been used to study rare-earth and actinide-ion-exchanged small pore (A) and large pore (Y) zeolites. A theoretical discussion of the RBS method and a novel method of data treatment are given. Experimental data for zeolites have been simulated and theoretical depth profiles have been determined. Both experimental and theoretical data suggest that uranyl-exchanged A zeolite has a large uranium to oxygen surface ratio while the corresponding Y zeolite has a large uranium to oxygen bulk ratio. Relative atomic fractions of all zeolite elements are also given.

  5. Selective sensing of alcohols in water influenced by chemically Zeolite coatings on optical fiber sensors

    NASA Astrophysics Data System (ADS)

    Nazari, Marziyeh; Hill, Matthew R.; Duke, Mikel; Sidiroglou, Fotios; Collins, Stephen F.

    2014-05-01

    The application of a MFI type zeolite coating on the end of an optical fiber is presented. Zeolite coatings were directly grown on the freshly cleaved endface of optical fibers. It was found that the produced integrated zeolite-fiber sensors exhibit specific chemical sensitivity towards certain chemicals. The molecular adsorption induced change of zeolite refractive index was studied to understand the sensing mechanisms of the developed sensor system. This work can lead to a new class of portable zeolite thin film enabled miniaturized fiber optic sensors.

  6. Thermal expansion of copper

    SciTech Connect

    Wang, K.; Reeber, R.R.

    1996-04-01

    The product of thermal expansion, bulk modulus, and volume, {alpha}{sub v}K{sub T}V, is the partial temperature derivative of the work done by thermal pressure. For copper this thermodynamic product resembles a specific heat (C{sub v}) curve and approaches a constant at high temperature. A recently developed model utilizes available data for this parameter and recommends new copper thermal expansion values from 0 K to the melting point.

  7. Copper tolerance and copper accumulation of herbaceous plants colonizing inactive California copper mines

    SciTech Connect

    Kruckeberg, A.L.; Wu, L. )

    1992-06-01

    Herbaceous plant species colonizing four copper mine waste sites in northern California were investigated for copper tolerance and copper accumulation. Copper tolerance was found in plant species colonizing soils with high concentrations of soil copper. Seven of the eight plant species tested were found at more than one copper mine. The mines are geographically isolated, which makes dispersal of seeds from one mine to another unlikely. Tolerance has probably evolved independently at each site. The nontolerant field control population of Vulpia microstachya displays significantly higher tolerance to copper at all copper concentration levels tested than the nontolerant Vulpia myrous population, and the degree of copper tolerance attained by V. microstachya at the two copper mines was much greater than that found in V. myrous. It suggests that even in these two closely related species, the innate tolerance in their nontolerant populations may reflect their potential for evolution of copper tolerance and their ability to initially colonize copper mine waste sites. The shoot tissue of the copper mine plants of Arenaria douglasii, Bromous mollis, and V. microstachya accumulated less copper than those plants of the same species from the field control sites when the two were grown in identical conditions in nutrient solution containing copper. The root tissue of these mine plants contain more copper than the roots of the nonmine plants. This result suggests that exclusion of copper from the shoots, in part by immobilization in the roots, may be a feature of copper tolerance. No difference in the tissue copper concentration was detected between tolerant and nontolerant plants of Lotus purshianus, Lupinus bicolor, and Trifolium pratense even though the root tissue had more copper than the leaves.

  8. Synthetic Zeolites and Other Microporous Oxide Molecular Sieves

    NASA Astrophysics Data System (ADS)

    Sherman, John D.

    1999-03-01

    Use of synthetic zeolites and other microporous oxides since 1950 has improved insulated windows, automobile air-conditioning, refrigerators, air brakes on trucks, laundry detergents, etc. Their large internal pore volumes, molecular-size pores, regularity of crystal structures, and the diverse framework chemical compositions allow "tailoring" of structure and properties. Thus, highly active and selective catalysts as well as adsorbents and ion exchangers with high capacities and selectivities were developed. In the petroleum refining and petrochemical industries, zeolites have made possible cheaper and lead-free gasoline, higher performance and lower-cost synthetic fibers and plastics, and many improvements in process efficiency and quality and in performance. Zeolites also help protect the environment by improving energy efficiency, reducing automobile exhaust and other emissions, cleaning up hazardous wastes (including the Three Mile Island nuclear power plant and other radioactive wastes), and, as specially tailored desiccants, facilitating the substitution of new refrigerants for the ozone-depleting chlorofluorocarbons banned by the Montreal Protocol.

  9. Aluminum Redistribution during the Preparation of Hierarchical Zeolites by Desilication.

    PubMed

    Mitchell, Sharon; Milina, Maria; Verel, René; Hernández-Rodríguez, Manuel; Pinar, Ana B; McCusker, Lynne B; Pérez-Ramírez, Javier

    2015-09-28

    A literature survey reveals a prominent reduction in the concentration of Brønsted acid sites in hierarchically organized zeolites with increasing mesoporous or external surface area independent of the framework type or synthesis route; this suggests a common fundamental explanation. To determine the cause, nature, and impact of the underlying changes in aluminum speciation, this study combines a multitechnique analysis that integrates basic characterization, a detailed synchrotron XRD and multiple-quantum NMR spectroscopy assessment, and catalytic tests to correlate evolution of the properties with performance during successive steps in the preparation of hierarchical MFI-type zeolites by desilication. The findings, subsequently generalized to FAU- and BEA-type materials, identify the crucial impact of calcination on the protonic form, which is an integral step in the synthesis and regeneration of zeolite catalysts; on aluminum coordination; and the associated acidity trends. PMID:26268428

  10. Direct Dual-Template Synthesis of MWW Zeolite Monolayers.

    PubMed

    Margarit, Vicente J; Martínez-Armero, Marta E; Navarro, M Teresa; Martínez, Cristina; Corma, Avelino

    2015-11-01

    A two-dimensional zeolite with the topology of MWW sheets has been obtained by direct synthesis with a combination of two organic structure-directing agents. The resultant material consists of approximately 70?% single and double layers and displays a well-structured external surface area of about 300?m(2) ?g(-1) . The delaminated zeolite prepared by means of this single-step synthetic route has a high delamination degree, and the structural integrity of the MWW layers is well preserved. The new zeolite material displayed excellent activity, selectivity, and stability when used as a catalyst for the alkylation of benzene with propylene and found to be superior to the catalysts that are currently used for producing cumene. PMID:26381669

  11. Heterogeneous radiolysis of CO 2 in the presence of zeolites

    NASA Astrophysics Data System (ADS)

    Garibov, A. A.; Velibekova, G. Z.; Agayev, T. N.

    Radiation catalytic activity of different zeolites Ca A, Na X, Na Y, LiNa Y, Ba M in CO 2 radiolysis has been investigated. This has led to studies in the catalyst porosity, the number of adsorbed CO 2 molecules and adsorption forces on their surface on the yield of CO 2 radiolysis products. A mechanism has been suggested for the observed CO 2 radiolysis processes over different zeolites. One of the possible ways to increase CO yield in radiolytic processes of CO 2 decomposition is to use various types of catalyst. (1-3) Therefore, the development of a scientific basis for appropriate catalyst selection is becoming of particular interest. For this purpose, heterogeneous CO 2 radiolysis in the presence of high-silica zeolites has been studied in this paper.

  12. Catalytic pyrolysis using UZM-39 aluminosilicate zeolite

    DOEpatents

    Nicholas, Christopher P; Boldingh, Edwin P

    2014-10-07

    A new family of coherently grown composites of TUN and IMF zeotypes has been synthesized and shown to be effective catalysts for catalytic pyrolysis of biomass. These zeolites are represented by the empirical formula. Na.sub.nM.sub.m.sup.n+R.sub.rQ.sub.qAl.sub.1-xE.sub.xSi.sub.yO.s- ub.z where M represents zinc or a metal or metals from Group 1, Group 2, Group 3 or the lanthanide series of the periodic table, R is an A,.OMEGA.-dihalosubstituted paraffin such as 1,4-dibromobutane, Q is a neutral amine containing 5 or fewer carbon atoms such as 1-methylpyrrolidine and E is a framework element such as gallium. The process involves contacting a carbonaceous biomass feedstock with UZM-39 at pyrolysis conditions to produce pyrolysis gases comprising hydrocarbons. The catalyst catalyzes a deoxygenation reaction converting oxygenated hydrocarbons into hydrocarbons and removing the oxygen as carbon oxides and water. A portion of the pyrolysis gases is condensed to produce low oxygen biomass-derived pyrolysis oil.

  13. Organic zeolites from a diolefinic monomer.

    PubMed

    Guney-Altay, Ozge; Pestov, Dmitry; Tepper, Gary

    2007-11-14

    Submicrometer particles of diethyl p-phenylenediacrylate (EPA) with tunable molecular adsorption characteristics were produced by solid-state photopolymerization in the presence of template molecules. EPA monomer particles were produced by rapid expansion of supercritical solutions (RESS), and deposited directly onto surface acoustic wave (SAW) resonators. The EPA particles were photopolymerized directly on the SAW devices in the presence of molecular templates, and dynamic sorption isotherms of C1- through C9-alkanes were studied to characterize the particle-vapor interaction. The mass increase due to vapor uptake into the particulate coatings was measured by monitoring the SAW resonance frequency during vapor sorption. The vapor selectivity and molecular porosity of the particulate coatings were studied in situ on the piezoelectric substrate by measuring sorption isotherms. A gradual exclusion of smaller alkane molecules from the molecularly imprinted particulate coatings was observed with decreasing template molecule size. The observed selective and reversible adsorption of alkane analytes with different molecular sizes suggest that these imprinted polymers may be categorized as organic analogues of zeolites. PMID:17948997

  14. Catalytic pyrolysis using UZM-39 aluminosilicate zeolite

    DOEpatents

    Nicholas, Christpher P; Boldingh, Edwin P

    2013-12-17

    A new family of coherently grown composites of TUN and IMF zeotypes has been synthesized and show to be effective catalysts for catalytic pyrolysis of biomass. These zeolites are represented by the empirical formula. Na.sub.nM.sub.m.sup.n+R.sub.rQ.sub.qAl.sub1-xE.sub.xSi.sub.yO.s- ub.z where M represents zinc or a metal or metals from Group 1, Group 2, Group 3 or the lanthanide series of the periodic table, R is an A,.OMEGA.-dihalosubstituted paraffin such as 1,4-dibromobutane, Q is a neutral amine containing 5 or fewer carbon atoms such as 1-methylpyrrolidine and E is a framework element such as gallium. The process involves contacting a carbonaceous biomass feedstock with UZM-39 at pyrolysis conditions to produce pyrolysis gases comprising hydrocarbons. The catalyst catalyzes a deoxygenation reaction converting oxygenated hyrdocarbons into hydrocarbons removing the oxygen as carbon oxides and water. A portion of the pyrolysis gases is condensed to produce low oxygen biomass-derived pyrolysis oil.

  15. Variation in performance of surfactant loading and resulting nitrate removal among four selected natural zeolites.

    PubMed

    Guan, Huade; Bestland, Erick; Zhu, Chuanyu; Zhu, Honglin; Albertsdottir, Dora; Hutson, John; Simmons, Craig T; Ginic-Markovic, Milena; Tao, Xian; Ellis, Amanda V

    2010-11-15

    Surfactant modified zeolites (SMZs) have the capacity to target various types of water contaminants at relatively low cost and thus are being increasingly considered for use in improving water quality. It is important to know the surfactant loading performance of a zeolite before it is put into application. In this work we compare the loading capacity of a surfactant, hexadecyltrimethylammonium bromide (HDTMA-Br), onto four natural zeolites obtained from specific locations in the USA, Croatia, China, and Australia. The surfactant loading is examined using thermogravimetric analysis (TGA), Fourier transform infrared (FT-IR) spectroscopy, and Raman spectroscopy. We then compare the resulting SMZs performance in removing nitrate from water. Results show that TGA is useful to determine the HDTMA loading capacity on natural zeolites. It is also useful to distinguish between a HDTMA bi-layer and a HDTMA mono-layer on the SMZ surface, which has not been previously reported in the literature. TGA results infer that HDTMA (bi-layer) loading decreases in the order of US zeolite>Croatian zeolite>Chinese zeolite>Australian zeolite. This order of loading explains variation in performance of nitrate removal between the four SMZs. The SMZs remove 8-18 times more nitrate than the raw zeolites. SMZs prepared from the selected US and Croatian zeolites were more efficient in nitrate removal than the two zeolites commercially obtained from Australia and China. PMID:20709446

  16. Statistical Approach to the Transformation of Fly Ash into Zeolites

    NASA Astrophysics Data System (ADS)

    Derkowski, Arkadiusz; Michalik, Marek

    2007-01-01

    The experimental conversion of F-class fly ash into zeolites is described. The ash, composed mainly of aluminosilicate glass, mullite and quartz, was collected in the Cracow power plant (southern Poland). The experiments involved the heating of fly ash samples in PTFE vessels. Time, temperature and solution composition were the reaction parameters considered in the experiments and in the subsequent modeling. A series of reactions with 0.5, 3 and 5M NaOH solutions (and some with additional 3M NaCl) were carried out at 70°, 100° and 150°C for 12-48 hours under autogenic pressure (not measured) and at a constant ash-to-solution ratio of 33.3 g/l. The following zeolite phases were synthesized: sodalite (SOD structure), hydroxysodalite (SOD), CAN type phases, Na-X (FAU), and NaP1 (GIS). Statistically calculated relationships based on the mineral- and chemical compositions of the reaction products support the conclusion that the type of zeolite phase that crystallizes depends on the concentration of OH- and Cl- in solution and on the temperature of the reaction. The duration of reaction, if on the order of tens of hours, is of less significance. The nature of the zeolite phase that crystalises is controlled by the intensity and selectivity of the substrate dissolution. That dissolution can favour, in sequence, one or other of the components in the substrate, resulting in Si/Al variation in the reaction solutions. Mullite dissolution (decreasing solution Si/Al) characterizes the most advanced reaction stages. The sequence of crystallization of the zeolite phases mirrors the sequential dissolution of substrate components, and the composition of the crystallizing zeolite crystals reflects the changes in the solution Si/Al.

  17. Monodispersed Ultrafine Zeolite Crystal Particles by Microwave Hydrothermal Synthesis

    SciTech Connect

    Hu, Michael Z.; Harris, Michael Tyrone; Khatri, Lubna

    2008-01-01

    Microwave hydrothermal synthesis of zeolites is reviewed. Monodispersed ultrafine crystal particles of zeolite (Silicalite-1) have been synthesized in batch reactor vessels by microwave irradiation heating of aqueous basic silicate precursor solutions with tetra propyl ammonium hydroxide as the templating molecule. The effects of major process parameters (such as synthesis temperature, microwave heating rate, volume ratio (i.e., the volume of the initial synthesis solution over the total volume of the reactor vessel), and synthesis time on the zeolite particle characteristics are studied using a computer-controlled microwave reactor system that allows real-time monitoring and control of reaction medium temperature. The changes in the morphology, size and crystal structure of the particles are investigated using scanning electron microscope, dynamic light scattering, X-ray diffraction, and BET surface analysis. We have found that the synthesis temperature, volume ratio, and heating rate play a significant role in controlling the particle size, uniformity, and morphology. Microwave processing has generated new morphologies of zeolite particles (i.e., uniform block-shaped particles that contain mixed gel-nanocrystallites and agglomerated crystal particles) that could not be made by a conventional hydrothermal process. At higher synthesis temperature and lower volume ratio, irregular block-shaped particles were produced, whereas increasing the volume ratio promoted the formation of monodispersed single-crystal particles with uniform shape. Our results clearly demonstrate that faster microwave heating is advantageous to enhance the zeolite crystallization kinetics and produces larger-size crystal particles in shorter time. In addition, zeolite crystallization mechanisms, depending on the microwave heating rate, were also discussed.

  18. Influence of Crystal Expansion/Contraction on Zeolite Membrane Permeation

    SciTech Connect

    Sorenson, Stephanie G; Payzant, E Andrew; Noble, Richard D; Falconer, John L.

    2010-01-01

    X-ray diffraction was used to measure the unit cell parameters of B-ZSM-5, SAPO-34, and NaA zeolite powders as a function of adsorbate loading at 303 K, and in one case, at elevated temperatures. Most adsorbates expanded the zeolite crystals below saturation loading at 303 K: n-hexane and SF6 in B-ZSM-5, methanol and CO2 in SAPO-34, and methanol in NaA zeolite. As the loadings increased, the crystals expanded more. Changes in the unit cell volumes of B-ZSM-5 and SAPO-34 zeolite powders correlated with changes in permeation through zeolite membranes defects. When the zeolite crystals expanded or contracted upon adsorption, the defect sizes decreased or increased. In B-ZSM-5 membranes, the fluxes through defects decreased dramatically when n-hexane or SF6 adsorbed. In contrast, i-butane adsorption at 303 K contracted B-ZSM-5 crystals at low loadings and expanded them at higher loadings. Correspondingly, the flux through B-ZSM-5 membrane defects increased at low i-butane loadings and decreased at high loading because the defects increased in size at low loading and decreased at high loadings. At 398 K and 473 K, n-hexane expanded the B-ZSM-5 unit cell more as the temperature increased from 303 to 473 K. The silicalite-1 and B-ZSM-5 unit cell volumes expanded similarly upon n-hexane adsorption at 303 K; boron substitution had little effect on volume expansion.

  19. Experiments with Zeolites at the Secondary School Level: Experience from The Netherlands

    NASA Astrophysics Data System (ADS)

    Coker, Eric N.; Davis, Pamela J.; Kerkstra, Aonne; van Bekkum, Herman

    1999-10-01

    This article describes a number of experiments that involve zeolites and are suitable for secondary-school chemistry laboratories. The experiments have been introduced successfully into secondary schools in The Netherlands. Zeolites are used in enormous quantities as builders (water softeners) in laundry detergents; they account for 15-30 wt % of most laundry detergents currently on the European market. In a series of experiments, students test the hardness of tap water before and after treatment with some zeolite and perform tests with a range of commercial laundry detergents containing zeolites. Zeolites are also used as catalysts in numerous industrial processes; another experiment described here highlights the use of zeolites as recyclable catalysts in an esterification reaction. A duplicate reaction is carried out in parallel, but using the conventional sulfuric acid catalyst instead of the zeolite. This experiment provides a good example of the benefit of a recyclable, heterogeneous catalyst over the conventional homogeneous one that is discarded as waste material.

  20. 21 CFR 73.1125 - Potassium sodium copper chloropyhllin (chlorophyllin-copper complex).

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ...2010-04-01 2010-04-01 false Potassium sodium copper chloropyhllin (chlorophyllin-copper...CERTIFICATION Drugs § 73.1125 Potassium sodium copper chloropyhllin (chlorophyllin-copper...Identity. (1) The color additive potassium sodium copper chlorophyllin is...

  1. 21 CFR 73.1125 - Potassium sodium copper chloropyhllin (chlorophyllin-copper complex).

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ...2012-04-01 2012-04-01 false Potassium sodium copper chloropyhllin (chlorophyllin-copper...CERTIFICATION Drugs § 73.1125 Potassium sodium copper chloropyhllin (chlorophyllin-copper...Identity. (1) The color additive potassium sodium copper chlorophyllin is...

  2. 21 CFR 73.2125 - Potassium sodium copper chlorophyllin (chlorophyllin-copper complex).

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ...2011-04-01 2011-04-01 false Potassium sodium copper chlorophyllin (chlorophyllin-copper...CERTIFICATION Cosmetics § 73.2125 Potassium sodium copper chlorophyllin (chlorophyllin-copper...specifications. The color additive potassium sodium copper chlorophyllin shall...

  3. 21 CFR 73.2125 - Potassium sodium copper chlorophyllin (chlorophyllin-copper complex).

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ...2014-04-01 2014-04-01 false Potassium sodium copper chlorophyllin (chlorophyllin-copper...CERTIFICATION Cosmetics § 73.2125 Potassium sodium copper chlorophyllin (chlorophyllin-copper...specifications. The color additive potassium sodium copper chlorophyllin shall...

  4. 21 CFR 73.2125 - Potassium sodium copper chlorophyllin (chlorophyllin-copper complex).

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ...2012-04-01 2012-04-01 false Potassium sodium copper chlorophyllin (chlorophyllin-copper...CERTIFICATION Cosmetics § 73.2125 Potassium sodium copper chlorophyllin (chlorophyllin-copper...specifications. The color additive potassium sodium copper chlorophyllin shall...

  5. 21 CFR 73.2125 - Potassium sodium copper chlorophyllin (chlorophyllin-copper complex).

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ...2010-04-01 2010-04-01 false Potassium sodium copper chlorophyllin (chlorophyllin-copper...CERTIFICATION Cosmetics § 73.2125 Potassium sodium copper chlorophyllin (chlorophyllin-copper...specifications. The color additive potassium sodium copper chlorophyllin shall...

  6. 21 CFR 73.1125 - Potassium sodium copper chloropyhllin (chlorophyllin-copper complex).

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ...2014-04-01 2014-04-01 false Potassium sodium copper chloropyhllin (chlorophyllin-copper...CERTIFICATION Drugs § 73.1125 Potassium sodium copper chloropyhllin (chlorophyllin-copper...Identity. (1) The color additive potassium sodium copper chlorophyllin is...

  7. 21 CFR 73.2125 - Potassium sodium copper chlorophyllin (chlorophyllin-copper complex).

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ...2013-04-01 2013-04-01 false Potassium sodium copper chlorophyllin (chlorophyllin-copper...CERTIFICATION Cosmetics § 73.2125 Potassium sodium copper chlorophyllin (chlorophyllin-copper...specifications. The color additive potassium sodium copper chlorophyllin shall...

  8. 21 CFR 73.1125 - Potassium sodium copper chloropyhllin (chlorophyllin-copper complex).

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ...2013-04-01 2013-04-01 false Potassium sodium copper chloropyhllin (chlorophyllin-copper...CERTIFICATION Drugs § 73.1125 Potassium sodium copper chloropyhllin (chlorophyllin-copper...Identity. (1) The color additive potassium sodium copper chlorophyllin is...

  9. 21 CFR 73.1125 - Potassium sodium copper chloropyhllin (chlorophyllin-copper complex).

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ...2011-04-01 2011-04-01 false Potassium sodium copper chloropyhllin (chlorophyllin-copper...CERTIFICATION Drugs § 73.1125 Potassium sodium copper chloropyhllin (chlorophyllin-copper...Identity. (1) The color additive potassium sodium copper chlorophyllin is...

  10. Modif : User Guide Page 1 Modif Documentation

    E-print Network

    Brest, Université de

    ..................................................................................................... 7 #12;Modif : User Guide Page 3 Installation Prerequisites EMF (http://wiki.eclipse.org/EMF/Installation#Install_EMF and EMF operations. Skip this part if you have already installed ATL and Kermeta. - Install Eclipse

  11. Entropy-driven pumping across zeolites and biological channels

    E-print Network

    Tom Chou; Detlef Lohse

    1999-05-01

    When two binary solutions are separated by a permeable barrier, the individual species typically diffuse and mix, dissipating their chemical potential gradients. However, we use model lattice simulations to show that single-file molecular-sized channels (such biomembrane channels and zeolites) can exhibit diffusional pumping, where one type of particle uses its entropy of mixing to drive another up its chemical potential gradient. Quantitative analyses of rates and efficiencies of transport are plotted as functions of transmembrane potential, pore length, and particle-pore interactions. Our results qualitatively explain recent measurements of ``negative'' osmosis and suggest new, more systematic experiments, particularly in zeolite transport systems.

  12. Method for encapsulating nanoparticles in a zeolite matrix

    DOEpatents

    Coker, Eric N. (Albuquerque, NM)

    2007-12-11

    A method for preparing a metal nanocluster composite material. A porous zeolitic material is treated with an aqueous metal compound solution to form a metal ion-exchanged zeolitic material, heated at a temperature ramp rate of less than 2.degree. C./min to an elevated temperature, cooled, contacted with an organic monomer and heating to induce polymerization, and heating the composite material to greater than 350.degree. C. under non-oxidizing conditions to form a metal nanocluster-carbon composite material with nanocluster sizes between approximately 0.6 nm and 10 nm.

  13. Zeolites replacing plant fossils in the Denver formation, Lakewood, Colorado.

    USGS Publications Warehouse

    Modreski, P.J.; Verbeek, E.R.; Grout, M.A.

    1984-01-01

    Well-developed crystals of heulandite and stilbite, within fossil wood, occur in sedimentary rocks in Lakewood, Jefferson County. The rocks belong to the Denver formation, a locally fossiliferous deposit of fluvial claystone, siltstone, sandstone and conglomerate, containing some volcanic mudflows (andesitic) of late Cretaceous to Palaeocene age. Altered volcanic glass released Na and Ca into the ground-water and subsequently zeolites were crystallized in the open spaces between grains and within fossil plant structures. Minor pyrite, quartz (jasper), calcite and apatite also occur as replacements of fossil wood. Similar zeolite occurrences in other areas are reviewed.-R.S.M.

  14. Zeolite catalysis in the synthesis of isobutylene from hydrous ethanol

    NASA Astrophysics Data System (ADS)

    Phillips, Cory Bernard

    1999-11-01

    This work deals with the synthesis of isobutylene from a hydrous ethanol feedstock over zeolites. The synthesis is accomplished in three steps: (1) low-temperature direct ethanol conversion to ethylene on H-ZSM-5 zeolite, (2) ethylene conversion to butene products over metal-exchanged zeolites, and (3) butene skeletal rearrangement to isobutylene over FER zeolites. The key to understanding and optimizing each synthesis step lies in the ability to control and regulate the zeolite acidity (Bronsted and Lewis)---both strength and number. Therefore, the continuous temperature programmed amine desorption (CTPAD) technique was further developed to simultaneously count the Bronsted acid sites and quantitatively characterize their strength. The adsorption of ethanol, reaction products, amines, coke and ethanol-derived residue (EDR) were monitored gravimetrically using the highly sensitive, novel Tapered Element Oscillating Microreactor (TEOM) apparatus. The TEOM was also used also in conjunction with CTPAD to characterize Bronsted acidity which is a new application for the instrument. For the first synthesis step, a parallel reaction exists which simultaneously produces diethyl ether and ethylene directly over H-ZSM-5. The reaction rates for each pathway were measured directly using a differential reactor operating at low temperatures (<473 K). Water in the ethanol feed enhances the rate of ethylene formation. A mechanism and kinetic expression are proposed for this reaction over H-ZSM-5, with diethyl-ether desorption and ethylene formation as the rate limiting steps. Heat of adsorption values measured from the independent microcalorimetry work reported in the literature are incorporated into the kinetic analysis which reduces the number of regressed parameters. For the remaining synthesis steps, several zeolite structures (ZSM-5, Y, FER) partially exchanged with Pd, Ti, Ni and Au were prepared and tested. It was determined from this screening study that the zeolites containing Pd are the most efficient catalysts for the dimerization reaction. Characterization results from x-ray diffraction (XRD), electron paramagnetic resonance (EPR) spectroscopy, and CTPAD suggest a stable, Pd species with a low oxidation state as part of the active site in Pd-exchanged zeolites. Isobutylene was present in the C4 fraction at reasonable quantities for most of the catalyst candidates, especially those containing an alkali metal co-cation.

  15. Infrared spectroscopic examination of the interaction of urea with the naturally occurring zeolite clinoptilolite

    USGS Publications Warehouse

    Byler, D.M.; Gerasimowicz, W.V.; Stockette, V.M.; Eberl, D.D.

    1991-01-01

    Infrared spectroscopy has shown for the first time that the naturally occurring zeolite clinoptilolite can absorb urea, (NH2)2CO, under ambient conditions from either aqueous or ethanolic solutions. The two strongest NH stretching bands at 3441 and 3344 cm-1 in pure, solid urea shift to higher frequency (about 3504 and 3401 cm-1) after absorption. Two of the four urea bands in the 1800-1300 cm-1 range (at 1683 and 1467 cm-1) undergo marked downward shifts to about 1670 and 1445 cm-1. The other two bands show little change in frequency. The strong band at 1602 cm-1, however, diminishes in intensity to little more than an ill-defined shoulder on the 1626-cm-1 peak. When clinoptilolite is heated to 450 ??C and then treated with molten urea (ca. 140 ??C) for several minutes, and finally washed twice with ethanol to remove excess unreacted urea, further changes become apparent in the spectrum of the urea-treated clinoptilolite. The two NH stretching bands broaden without significant change in frequency. Two new bands appear in the midfrequency range at 1777 (weak) and 1719 (medium strong) cm-1. Of the four original midfrequency peaks, the one at 1602 cm-1 is now absent. Two others (1627 and 1440 cm-1) exhibit little change, while the fourth has broadened and shifted down to 1663 cm-1, where it appears as a shoulder on the band at 1627 cm-1. Both treatments clearly induce interaction between urea and the zeolite which seems to result in significant modifications in the nature of the hydrogen bonding of the substrate. ?? 1991.

  16. The growth of zeolites A, X and mordenite in space

    NASA Technical Reports Server (NTRS)

    Sacco, Albert, Jr.; Bac, N.; Coker, E. N.; Dixon, A. G.; Warzywoda, J.; Thompson, R. W.

    1994-01-01

    Zeolites are a class of crystalline aluminosilicate materials that form the backbone of the chemical process industry worldwide. They are used primarily as adsorbents and catalysts and support to a significant extent the positive balance of trade realized by the chemical industry in the United States (around $19 billion in 1991). The magnitude of their efforts can be appreciated when one realizes that since their introduction as 'cracking catalysts' in the early 1960's, they have saved the equivalent of 60 percent of the total oil production from Alaska's North Slope. Thus the performance of zeolite catalysts can have a profound effect on the U.S. economy. It is estimated that a 1 percent increase in yield of the gasoline fraction per barrel of oil would represent a savings of 22 million barrels of crude oil per year, representing a reduction of $400 million in the United States' balance of payments. Thus any activity that results in improvement in zeolite catalyst performance is of significant scientific and industrial interest. In addition, due to their 'stability,' uniformity, and, within limits, their 'engineerable' structures, zeolites are being tested as potential adsorbents to purify gases and liquids at the parts-per-billion levels needed in today's electronic, biomedical, and biotechnology industries and for the environment. Other exotic applications, such as host materials for quantum-confined semiconductor atomic arrays, are also being investigated. Because of the importance of this class of material, extensive efforts have been made to characterize their structures and to understand their nucleation and growth mechanisms, so as to be able to custom-make zeolites for a desired application. To date, both the nucleation mechanics and chemistry (such as what are the 'key' nutrients) are, as yet, still unknown for many, if not all, systems. The problem is compounded because there is usually a 'gel' phase present that is assumed to control the degree of supersaturation, and this gel undergoes a continuous 'polymerization' type reaction during nucleation and growth. Generally, for structure characterization and diffusion studies, which are useful in evaluating zeolites for improving yield in petroleum refining as well as for many of the proposed new applications (e.g., catalytic membranes, molecular electronics, chemical sensors) large zeolites (greater than 100 to 1000 times normal size) with minimum lattice defects are desired. Presently, the lack of understanding of zeolite nucleation and growth precludes the custom design of zeolites for these or other uses. It was hypothesized that the microgravity levels achieved in an orbiting spacecraft could help to isolate the possible effects of natural convection (which affects defect formation) and minimize sedimentation, which occurs since zeolites are twice as dense as the solution from which they are formed. This was expected to promote larger crystals by allowing growing crystals a longer residence time in a high-concentration nutrient field. Thus it was hypothesized that the microgravity environment of Earth orbit would allow the growth of large, more defect-free zeolite crystals in high yield.

  17. The influence of chemisorbed molecules on mass transfer in H-ZSM-5-type zeolites and the location of Broensted acid sites

    SciTech Connect

    Caro, J.; Buelow, M. ); Kaerger, J.; Pfeifer, H. )

    1988-11-01

    Heterogeneous catalysis is one of the most important applications of zeolites. Therefore, various methods have been developed to determine the strength and concentration of Bronsted acid sites in zeolites. Among them, in the last few years, {sup 1}H MAS NMR has become a powerful tool. In addition to the accessibility of the acid sites probed by chemisorption of N-bases, the steric environment of these catalytically active sites is of importance since it imposes constraints on the geometry of the transition state. However, only a few studies have been reported on this topic. Information was obtained from quantum chemical calculations, catalytic experiments, I.R. spectroscopy, and the arrangement of guest molecules. From these investigations it has been concluded that in H-ZSM-5 the channel intersections should be preferential location centers for the Bronsted acid sites. In adsorption technology, in the use of zeolites as shape-selective adsorbents, modification of the molecular sieve properties by chemisorption of nitrogen-containing bases (N-compounds) has become a common technique. The authors have applied the NMR pulsed field gradient technique to study the influence of chemisorbed N-compounds on transport properties of molecular sieves, considering the chemisorbed compounds as transport obstacles.

  18. Copper Proteins and Oxygen

    PubMed Central

    Frieden, Earl; Osaki, Shigemasa; Kobayashi, Hiroshi

    1965-01-01

    A comprehensive survey of the interaction of the copper proteins and oxygen is presented including a correlation of structure, function, and other properties of the known copper oxidases and of hemocyanin. The origin of their blue color and the structure of copper complexes and copper proteins are related to the oxidation state of copper ion and relevant electronic transitions probably arising from the formation of charge transfer complexes. The oxygen reactions of hemocyanin, ceruloplasmin, and cytochrome oxidase show half-saturation values far below the other Cu enzymes. The formation of hydrogen peroxide as a reaction product is associated with the presence of one Cu atom per oxidase molecule or catalytic system. Water is the corresponding product of the other Cu oxidases with four or more Cu atoms per molecule, except for monoamine oxidase. Mechanisms for the oxidase action of the two and four electron transfer Cu oxidases and tyrosinase are proposed. These reactions account for the number, the oxidation-reduction potential, and the oxidation state of Cu in the resting enzyme, the cyclical change from Cu(II) to Cu(I), the diatomic nature of O2, the sequence of the oxidation and reduction reactions, and other salient features. The catalytic reactions involved in the oxidation of ascorbic acid by plant ascorbate oxidase, ceruloplasmin, and Cu(II) are compared. Finally the substrate specificity, inhibitory control, and the detailed mechanism of the oxidase activity of ceruloplasmin are summarized. PMID:4285728

  19. Copper and copper-nickel alloys as zebra mussel antifoulants

    SciTech Connect

    Dormon, J.M.; Cottrell, C.M.; Allen, D.G.; Ackerman, J.D.; Spelt, J.K.

    1996-04-01

    Copper has been used in the marine environment for decades as cladding on ships and pipes to prevent biofouling by marine mussels (Mytilus edulis L.). This motivated the present investigation into the possibility of using copper to prevent biofouling in freshwater by both zebra mussels and quagga mussels (Dreissena polymorpha and D. bugensis collectively referred to as zebra mussels). Copper and copper alloy sheet proved to be highly effective in preventing biofouling by zebra mussels over a three-year period. Further studies were conducted with copper and copper-nickel mesh (lattice of expanded metal) and screen (woven wire with a smaller hole size), which reduced the amount of copper used. Copper screen was also found to be strongly biofouling-resistant with respect to zebra mussels, while copper mesh reduced zebra mussel biofouling in comparison to controls, but did not prevent it entirely. Preliminary investigations into the mechanism of copper antifouling, using galvanic couples, indicated that the release of copper ions from the surface of the exposed metal into the surrounding water is directly or indirectly responsible for the biofouling resistance of copper.

  20. 24-hour urine copper test

    MedlinePLUS

    The 24-hour urine copper test measures the amount of copper in a urine sample. ... A 24-hour urine sample is needed. On day 1, urinate into the toilet when you get up in the morning. Afterwards, collect ...

  1. Synthesis of zeolite beta in fluoride media under microwave irradiation

    E-print Network

    Kim, Ji Man

    , which results in rapid heating. Furthermore, the employment of the microwave tech- niqueSynthesis of zeolite beta in fluoride media under microwave irradiation Dae Sung Kim a , Jong been successfully prepared at 150 °C within 4 h by direct synthesis under microwave irradiation

  2. Zeolitic imidazolate frameworks for kinetic separation of propane and propene

    SciTech Connect

    Li, Jing; Li, Kunhao; Olson, David H.

    2014-08-05

    Zeolitic Imidazolate Frameworks (ZIFs) characterized by organic ligands consisting of imidazole ligands that are either essentially all 2-chloroimidazole ligands or essentially all 2-bromoimidazole ligands are disclosed. Methods for separating propane and propene with the ZIFs of the present invention, as well as other ZIFs, are also disclosed.

  3. Fenton Chemistry of FeIII Zeolitic Minerals Treated with

    E-print Network

    Dutta, Prabir K.

    Fenton Chemistry of FeIII -Exchanged Zeolitic Minerals Treated with Antioxidants T O N I A . R U D Fenton activity. Lung lining fluid contains antioxidants, such as glutathione (GSH) and ascorbic acid (AAIII- exchanged erionite and mordenite after treatment with antioxidants. The Fenton assay involved the reaction

  4. Selective photooxidation of hydrocarbons in zeolites by oxygen

    DOEpatents

    Frei, Heinz (Berkeley, CA); Blatter, Fritz (Berkeley, CA); Sun, Hai (Berkeley, CA)

    1998-01-01

    A selective photooxidation process for the conversion of hydrocarbon molecules to partially oxygenated derivatives, which comprises the steps of adsorbing a hydrocarbon and oxygen onto a dehydrated zeolite support matrix to form a hydrocarbon-oxygen contact pair, and subsequently exposing the hydrocarbon-oxygen contact pair to visible light, thereby forming a partially oxygenated derivative.

  5. Characterization of natural zeolite clinoptilolite for sorption of contaminants

    NASA Astrophysics Data System (ADS)

    Xingu-Contreras, E.; García-Rosales, G.; García-Sosa, I.; Cabral-Prieto, A.; Solache-Ríos, M.

    2015-06-01

    The nanoparticles technology has received considerable attention for its potential applications in groundwater treatment for the removal of various pollutants as Cadmium. In this work, iron boride nanoparticles were synthesized in pure form and in presence of homo-ionized zeolite clinoptilolite, as support material. These materials were used for removing Cd (II) from aqueous solutions containing 10, 50, 100, 150, 200, 250, 300 and 400 mg/L. The characterization of these materials was made by using X-ray Diffraction, Scanning Electron Microscopy and Mössbauer Spectroscopy. Pure iron boride particles show a broad X-ray diffraction peak centered at 45? (2 𝜃), inferring the presence of nanocrystals of Fe2B as identified from Mössbauer Spectroscopy. The size of these Fe2B particles was within the range of 50 and 120 nm. The maximum sorption capacities for Cd (II) of iron boride particles and supported iron boride particles in homo-ionized zeolitic material were nearly 100 %. For homo-ionized zeolite and homo-ionized zeolite plus sodium borohydride was ? 95 %.

  6. DIFFUSION MEASUREMENTS DURING PERVAPORATION THROUGH A ZEOLITE MEMBRANE

    EPA Science Inventory


    An isotopic-transient technique was used to directly measure diffusion times of H2O, methanol, ethanol, 2-propanol, and acetone in pure and binary mixture feeds transporting through a zeolite membrane under steady-state pervaporation conditions. Diffusivities can be determ...

  7. USE OF SYNTHETIC ZEOLITES FOR ARSENATE REMOVAL FROM POLLUTANT WATER

    EPA Science Inventory

    Arsenic is known to be a hazardous contaminant in drinking water that causes arsenical dermatitis and skin cancer. In the present work, the potential use of a variety of synthetic zeolites for removal of arsenic from water below the current and proposed EPA MCL has been examined...

  8. ADSORPTION AND CATALYTIC DESTRUCTION OF TRICHLOROETHYLENE IN HYDROPHOBIC ZEOLITES

    EPA Science Inventory

    Several chromium exchanged ZSM-5 zeolites of varying SiO2/Al2O3 ratio were prepared and investigated for ambient (23 ?C) adsorption and subsequent oxidative destruction (250-400 ?C) of gaseous trichloroethylene (TCE, Cl2C=CHCl) in a humid air stream. With an increase in the SiO2...

  9. High-silica zeolite nucleation from clear solutions 

    E-print Network

    Cheng, Chil-Hung

    2006-04-12

    /SANS), and nuclear magnetic resonance (NMR). While these studies have generated a more comprehensive picture on the silicalite-1 growth mechanism, the general application of the mechanism and how it could be applied to other zeolite systems have not been addressed...

  10. Association of Indigo with Zeolites for Improved Color Stabilization

    NASA Astrophysics Data System (ADS)

    Dejoie, Catherine; Martinetto, Pauline; Dooryhée, Eric; van Elslande, Elsa; Blanc, Sylvie; Bordat, Patrice; Brown, Ross; Porcher, Florence; Anne, Michel

    2010-10-01

    The durability of an organic colour and its resistance against external chemical agents and exposure to light can be significantly enhanced by hybridizing the natural dye with a mineral. In search for stable natural pigments, the present work focuses on the association of indigo blue with several zeolitic matrices (LTA zeolite, mordenite, MFI zeolite). The manufacturing of the hybrid pigment is tested under varying oxidising conditions, using Raman and UV-visible spectrometric techniques. Blending indigo with MFI is shown to yield the most stable composite in all of our artificial indigo pigments. In absence of defects and substituted cations such as aluminum in the framework of the MFI zeolite matrix, we show that matching the pore size with the dimensions of the guest indigo molecule is the key factor. The evidence for the high colour stability of indigo@MFI opens a new path for modeling the stability of indigo in various alumino-silicate substrates such as in the historical Maya Blue pigment.

  11. High-pressure alchemy on a small-pore zeolite

    NASA Astrophysics Data System (ADS)

    Lee, Y.

    2011-12-01

    While an ever-expanding variety of zeolites with a wide range of framework topology is available, it is desirable to have a way to tailor the chemistry of the zeolitic nanopores for a given framework topology via controlling both the coordination-inclusion chemistry and framework distortion/relaxation. This is, however, subjected to the ability of a zeolitic nanopore to allow the redistribution of cations-water assembly and/or insertion of foreign molecules into the pores and channels. Small-pore zeolites such as natrolite (Na16Al16Si24O80x16H2O), however, have been known to show very limited capacity for any changes in the confinement chemistry. We have recently shown that various cation-exchanged natrolites can be prepared under modest conditions from natural sodium natrolite and exhibit cation-dependent volume expansions by up to 18.5% via converting the elliptical channels into progressively circular ones. Here, we show that pressure can be used as a unique and clean tool to further manipulate the chemistry of the natrolite nanopores. Our recent crystallographic and spectroscopic studies of pressure-insertion of foreign molecules, trivalent-cation exchange under pressure, and pressure-induced inversion of cation-water coordination and pore geometry in various cation-exchanged natrolites will be presented.

  12. Zeolite formation from coal fly ash and its adsorption potential.

    PubMed

    Ruen-ngam, Duangkamol; Rungsuk, Doungmanee; Apiratikul, Ronbanchob; Pavasant, Prasert

    2009-10-01

    The possibility in converting coal fly ash (CFA) to zeolite was evaluated. CFA samples from the local power plant in Prachinburi province, Thailand, were collected during a 3-month time span to account for the inconsistency of the CFA quality, and it was evident that the deviation of the quality of the raw material did not have significant effects on the synthesis. The zeolite product was found to be type X. The most suitable weight ratio of sodium hydroxide (NaOH) to CFA was approximately 2.25, because this gave reasonably high zeolite yield with good cation exchange capacity (CEC). The silica (Si)-to-aluminum (Al) molar ratio of 4.06 yielded the highest crystallinity level for zeolite X at 79% with a CEC of 240 meq/100 g and a surface area of 325 m2/g. Optimal crystallization temperature and time were 90 degrees C and 4 hr, respectively, which gave the highest CEC of approximately 305 meq/100 g. Yields obtained from all experiments were in the range of 50-72%. PMID:19842322

  13. Differential thermal analysis as an acidity probe in zeolite catalysts

    SciTech Connect

    Aboul-Gheit, A.K.; Al-Hajjaji, M.A.; Menoufy, M.F.; Abdel-Hamid, S.M.

    1986-01-01

    Differential thermal analysis is used as an acidity strength probe for a series of mordenite (zeolite) catalysts via determining the temperature at which presorbed pyridine completely desorbs from the catalyst. The findings obtained for metal(s) containing mordenite catalysts have been correlated with the Pearson's assumption concerning Lewis acids and bases and the Pauling's electronegativity of the metals contained and found compatible.

  14. Zeolite formation from coal fly ash and its adsorption potential

    SciTech Connect

    Duangkamol Ruen-ngam; Doungmanee Rungsuk; Ronbanchob Apiratikul; Prasert Pavasant

    2009-10-15

    The possibility in converting coal fly ash (CFA) to zeolite was evaluated. CFA samples from the local power plant in Prachinburi province, Thailand, were collected during a 3-month time span to account for the inconsistency of the CFA quality, and it was evident that the deviation of the quality of the raw material did not have significant effects on the synthesis. The zeolite product was found to be type X. The most suitable weight ratio of sodium hydroxide (NaOH) to CFA was approximately 2.25, because this gave reasonably high zeolite yield with good cation exchange capacity (CEC). The silica (Si)-to-aluminum (Al) molar ratio of 4.06 yielded the highest crystallinity level for zeolite X at 79% with a CEC of 240 meq/100 g and a surface area of 325 m{sup 2}/g. Optimal crystallization temperature and time were 90{sup o}C and 4 hr, respectively, which gave the highest CEC of approximately 305 meq/100 g. Yields obtained from all experiments were in the range of 50-72%. 29 refs., 5 tabs., 7 figs.

  15. Association of indigo with zeolites for improved color stabilization.

    PubMed

    Dejoie, Catherine; Martinetto, Pauline; Dooryhée, Eric; Van Elslande, Elsa; Blanc, Sylvie; Bordat, Patrice; Brown, Ross; Porcher, Florence; Anne, Michel

    2010-10-01

    The durability of an organic color and its resistance against external chemical agents and exposure to light can be significantly enhanced by hybridizing the natural dye with a mineral. In search for stable natural pigments, the present work focuses on the association of indigo blue with several zeolitic matrices (LTA zeolite, mordenite, MFI zeolite). The manufacturing of the hybrid pigment is tested under varying oxidizing conditions, using Raman and ultraviolet-visible (UV-Vis) spectrometric techniques. Blending indigo with MFI is shown to yield the most stable composite in all of our artificial indigo pigments. In the absence of defects and substituted cations such as aluminum in the framework of the MFI zeolite matrix, we show that matching the pore size with the dimensions of the guest indigo molecule is the key factor. The evidence for the high color stability of indigo@MFI opens a new path for modeling the stability of indigo in various alumino-silicate substrates such as in the historical Maya Blue pigment. PMID:20925983

  16. Catalase-like activity studies of the manganese(II) adsorbed zeolites

    NASA Astrophysics Data System (ADS)

    ?içek, Ekrem; Dede, Bülent

    2013-12-01

    Preparation of manganese(II) adsorbed on zeolite 3A, 4A, 5A. AW-300, ammonium Y zeolite, organophilic, molecular sieve and catalase-like enzyme activity of manganese(II) adsorbed zeolites are reported herein. Firstly zeolites are activated at 873 K for two hours before contact manganese(II) ions. In order to observe amount of adsorption, filtration process applied for the solution. The pure zeolites and manganese(II) adsorbed zeolites were analysed by FT-IR. As a result according to the FT-IR spectra, the incorporation of manganese(II) cation into the zeolite structure causes changes in the spectra. These changes are expected particularly in the pseudolattice bands connected with the presence of alumino and silicooxygen tetrahedral rings in the zeolite structure. Furthermore, the catalytic activities of the Mn(II) adsorbed zeolites for the disproportionation of hydrogen peroxide were investigated in the presence of imidazole. The Mn(II) adsorbed zeolites display efficiency in the disproportion reactions of hydrogen peroxide, producing water and dioxygen in catalase-like activity.

  17. Facile synthesis of hollow zeolite microspheres through dissolution–recrystallization procedure in the presence of organosilanes

    SciTech Connect

    Tao, Haixiang; Ren, Jiawen; Liu, Xiaohui; Wang, Yanqin; Lu, Guanzhong

    2013-04-15

    Hollow zeolite microspheres have been hydrothermally synthesized in the presence of organosilanes via a dissolution–recrystallization procedure. In the presence of organosilanes, zeolite particles with a core/shell structure formed at the first stage of hydrothermal treatment, then the core was consumed and recrystallized into zeolite framework to form the hollow structure during the second hydrothermal process. The influence of organosilanes was discussed, and a related dissolution–recrystallization mechanism was proposed. In addition, the hollow zeolite microspheres exhibited an obvious advantage in catalytic reactions compared to conventional ZSM-5 catalysts, such as in the alkylation of toluene with benzyl chloride. - Graphical abstract: Hollow zeolite spheres with aggregated zeolite nanocrystals were synthesized via a dissolution–recrystallization procedure in the presence of organosiline. Highlights: ? Hollow zeolite spheres with aggregated zeolite nanocrystals were synthesized via a dissolution–recrystallization procedure. ? Organosilane influences both the morphology and hollow structure of zeolite spheres. ? Hollow zeolite spheres showed an excellent catalytic performance in alkylation of toluene with benzyl chloride.

  18. Hydrophobic Fe-zeolites for removal of MTBE from water by combination of adsorption and oxidation.

    PubMed

    Gonzalez-Olmos, Rafael; Kopinke, Frank-Dieter; Mackenzie, Katrin; Georgi, Anett

    2013-03-01

    Several zeolites were evaluated as adsorbents for the removal of MTBE from water in a screening process. It was observed that the SiO2/Al2O3 molar ratio is a decisive factor for the adsorption properties, at least in the case of ZSM5 zeolites. ZSM5 zeolites with SiO2/Al2O3 ratios >200 were found to provide the best sorption properties for MTBE. To design a combined sorption/reaction method, regeneration of the loaded zeolites by selected advanced oxidation processes (AOP) was studied: (1) Fenton treatment using H2O2 with dissolved iron salts and (2) heterogeneous Fenton-like oxidation with Fe immobilized on the zeolites. The first was ineffective in regenerating loaded zeolites. However, heterogeneous catalysis using Fe species immobilized on the zeolite by liquid ion exchange was markedly more effective. Although these hydrophobic zeolites have a low ion exchange capacity, resulting in iron loadings of ? 0.09 wt %, it was possible to obtain sufficiently active catalysts. Hydrophobic Fe-zeolites can therefore be regarded as promising materials for the removal of MTBE from water, since they allow the combination of efficient adsorption and oxidative degradation of MTBE by H2O2. In contrast to the homogeneous catalysis by dissolved iron ions, these heterogeneous catalysts work at near-neutral pH and can be easily reused. Fe-zeolites as adsorbents/catalysts showed a good stability in both batch and column experiments. PMID:23346998

  19. Clinoptilolite zeolitized tuff from Central Alborz Range, North Iran

    NASA Astrophysics Data System (ADS)

    Taghipour, Batoul

    2010-05-01

    Zeolites are hydrated alumino-silicates of the alkaline and alkaline earth cations, principally sodium, potassium, calcium, and magnesium (Iijima 1980; Hay 1981). Zeolites occur principally in unmetamorphosed sedimentary rocks and are particularly widespread in volcani-clastic strata (Hay, 1978). Clinoptilolite is a natural zeolite of the heulandite group with the simplified formula of (Na, K)6 Si30 Al6 O72 .nH2. It is the most common natural zeolite found mainly in sedimentary rocks of volcanic origin. Alborz zone is one of the important geological divisions in Iran. This zone is restricted to Kopeh dagh zone in North & Central Iranian zone in South and is a region of active deformation within the broad Arabian-Eurasia collision zone (Allen et al. 2003). The zeolitized green tuff belt from Central Alborz which introduce here are made of volcanoclastic sequence of Karaj Formation. This belt is about 40 km long along Alborz Range and is Eocene in age. Zeolites and associated minerals of this altered vitric tuff studied. Zeolitization took place in some beds of Karaj Formations, with average range of 3 to 300 meters thickness. There are several gypsum lenses which interbed with a widespread green tuff succession in the studied area. On the basis of chemical composition these tuffs are in the range of acid to intermediate volcanic rocks. Also magmatic affinity is calc-alkaline and geological setting of the area belongs to volcanic arc granitoid. Petrographic data has shown that various shape and size of shard glass are the main component of tuffs. Based on the field studies, detail microscopy, XRD and electron microprobe analysis (EMPA), the following main minerals are determined: Clinoptilolite+montmorillonite+crystobalite. Clinoptilolite and smectite are predominant minerals in all altered samples. Concerning the Si/Al ratio of 40 point analyses of glass shards the Alborz tuff has clinoptilolite composition. Otherwise the chemical composition of altered shard glass is very similar to clinoptilolite structural formula. By using medium results of chemical data the structural formula for Firuzkuh clinoptilolite is as follow: Si 29.91 Al 6.01 Fe2+ 951 Mg2+ 0.393 Ca 0.222 Na 3.162 K 1.422 Paleogeographic conditions have provided a marginal shallow seawater environment which has been filled by volcanoclastics sequence. In Eocene the zeolitization occur as layers which are confined stratigraphically, it seems this process that took place only in preferred tuffaceous horizons which enriched by shard glass. So the term staratabound can be used for this type zeolitization. In altered tuffs there are a close relationship between clinoptiloite and montmorilonite in some deposits. Alborz range, there was an occasionally marine environment (existence of marine microfossils) with humid climate (remnants of plants in some points). Transformation process (glass zeolite + smectite) provides a further silica contribution to the system, which finally in supersaturation and decreasing pH favors the precipitation of silica in altered tuff. This may have occurred when ground water flow become to mix with saline water to lowering the pH.

  20. High adherence copper plating process

    DOEpatents

    Nignardot, H.

    1993-09-21

    A process is described for applying copper to a substrate of aluminum or steel by electrodeposition and for preparing the surface of an aluminum or steel substrate for the electrodeposition of copper. Practice of the invention provides good adhesion of the copper layer to either substrate.

  1. Acid copper sulfate plating bath: Control of chloride and copper

    SciTech Connect

    Borhani, K.J.

    1992-08-01

    Plated-through holes in high-reliability printed wiring boards require a ductile copper plate of uniform consistency. The level of control of the chemical constituents in the electroplating solutions dictates the physical properties of the copper plate. To improve the control of the chemical bath constituents, in-situ methods for electrochemically determining copper and chloride in acid copper sulfate baths were developed. A solid-state ion-selective electrode was used for the chloride ion and proved to be more reproducible than conventional silver chloride turbidimetric methods. The use of a copper solid-state ion-selective electrode in-situ was also successful in this application.

  2. Experimental Investigation of the Effect Of Zeolite Coating Thickness on the Performance of a Novel Zeolite-Water Adsorption Heat Pump Module 

    E-print Network

    Dawoud, B.; Hofle, P.; Chmielewski, S.

    2010-01-01

    is an extruded aluminum finned-tube heat exchanger coated with AQSOA-Z02 zeolite of Mitsubishi Plastics Incorporation (MPI). The effect of the Zeolite layer thickness (300 and 500 micrometers) on the performance of the heat pump module has been experimentally...

  3. Methane emissions abatement by multi-ion-exchanged zeolite A prepared from both commercial-grade zeolite and coal fly ash

    SciTech Connect

    K.S. Hui; C.Y.H. Chao

    2008-10-01

    The performance of multimetal-(Cu, Cr, Zn, Ni, and Co)-ion-exchanged zeolite A prepared from both a commercial-grade sample and one produced from coal fly ash in methane emissions abatement was evaluated in this study. The ion-exchange process was used to load the metal ions in zeolite A samples. The methane conversion efficiency by the samples was studied under various parameters including the amount of metal loading (7.3-19.4 wt%), reaction temperature (25-500{sup o}C), space velocity (8400-41 900 h{sup -1}), and methane concentration (0.5-3.2 vol %). At 500{sup o}C, the original commercial-grade zeolite A catalyzed 3% of the methane only, whereas the addition of different percentages of metals in the sample enhanced the methane conversion efficiency by 40-85%. Greater methane conversion was observed by increasing the percentage of metals added to the zeolite even though the BET surface area of the zeolite consequently decreased. Higher percentage methane conversion over the multi-ion-exchanged samples was observed at lower space velocities indicating the importance of the mass diffusion of reactants and products in the zeolite. Compared to the multi-ion-exchanged zeolite A prepared from the commercial-grade zeolite, the one produced from coal fly ash demonstrated similar performances in methane emissions abatement, showing the potential use of this low cost recycled material in gaseous pollutant treatment. 25 refs., 3 figs., 2 tabs.

  4. Investigation of the Dynamics of a Screw Dislocation in Copper

    NASA Astrophysics Data System (ADS)

    Kolupaeva, S. N.; Petelina, Yu. P.; Polosukhin, K. A.; Petelin, A. E.

    2015-08-01

    A modification of the mathematical model of forming the crystallographic shear band is proposed in which the strength of elastic interaction between all dislocations of the forming dislocation pileups is taken into account in addition to the Peach-Keller force; lattice, impurity, and dislocation friction; linear tension; viscous braking; and intensity of generation of point defects behind kinks. The model is used to investigate the influence of the dislocation density on the time characteristics of the formation of dislocation loops in copper.

  5. Brazing copper to dispersion-strengthened copper

    SciTech Connect

    Ryding, D.G.; Allen, D.; Lee, R.

    1996-08-01

    The Advanced Photon Source (APS) is a state-of-the-art synchrotron light source that will produce intense x-ray beams, which will allow the study of smaller samples and faster reactions and processes at a greater level of detail that has been possible to date. The beam is produced by using third-generation insertion devices in a 7 GeV electron/positron storage ring that is 1100 meters in circumference. The heat load from these intense high power devices is very high and certain components must sustain total heat loads of 3 to 15 kW and heat fluxes of 30 W/mm{sup 2}. Because the beams will cycle on and off many times, thermal shock and fatigue will be a problem. High heat flux impinging on a small area causes a large thermal gradient that results in high stress. GlidCop{reg_sign}, a dispersion strengthened copper, is the desired material because of its high thermal conductivity and superior mechanical properties as compared to copper and its alloys. GlidCop is not amenable to joining by fusion welding, and brazing requires diligence because of high diffusivity. Brazing procedures were developed using optical and scanning electron microscopy.

  6. Fabrication of a superhydrophobic surface on copper foil based on ammonium bicarbonate and paraffin wax coating

    NASA Astrophysics Data System (ADS)

    Zeng, Ou; Wang, Xian; Yuan, Zhiqing; Wang, Menglei; Huang, Juan

    2015-09-01

    A simple and low cost approach was developed to fabricate a superhydrophobic surface on copper foil. The oxidation and etching of the copper foil surface were promoted in NH4HCO3 solution using a water and ethanol admixture as a component solvent. After 28 h in this solution, a hydrophilic rough surface structure was obtained on the copper foil surface. With modification using a paraffin wax coating, the hydrophilic rough copper surface changed to become hydrophobic or superhydrophobic. The surface morphology and wettability were characterized by scanning electron microscopy (SEM) and contact angle measurements, respectively. When the optimum concentration of paraffin wax was about 2 g L-1, its water contact angle could reach about 152 ± 1.5° and its sliding angle was around 7°. The formation mechanism of the rough copper surface was also explored in detail. Both the experimental process and the material are environmentally friendly.

  7. Oxygen removal from blister copper by copper oxide formation

    NASA Astrophysics Data System (ADS)

    Coursol, Pascal; Davis, Boyd; Roy, Alain; Lebel, Martin

    2005-07-01

    In this study, an alternative approach is proposed to remove oxygen from blister copper through copper oxide formation. The addition of fluxes promotes both the copper oxide formation and oxygen reduction in molten copper. Fundamental aspects of this proposed process are described in this article. Three different fluxes (Na2O-SiO2, CaO-Na2O, and FeO-Na2O-SiO2) were tested at the laboratory scale. This work showed encouraging results with oxygen in copper being reduced to industrial specifications without the conventional hydrocarbon reduction step. This approach could be used industrially to remove oxygen from blister copper prior to anode casting and points to a new concept in deoxygenation of copper.

  8. Enhanced Perchloroethylene Reduction Using Surfactant-Modified Zeolite/Zero-Valent Iron Pellets

    NASA Astrophysics Data System (ADS)

    Zhang, P.; Tao, X.; Bowman, R. S.

    2001-12-01

    We determined the effect of surfactant modification on perchloroethylene (PCE) reduction by zeolite/zero-valent iron (ZVI) pellets. We packed the pellets into four columns (30-cm long, 4.8-cm diameter) and modified two of the columns by sorbing the cationic surfactant hexadecyltrimethylammonium chloride (HDTMA-Cl) onto the pellets. We then continuously injected 11.0 ? M PCE into the columns and monitored the effluent concentrations of PCE, trichloroethylene (TCE), cis-, trans-, and 1,1-dichloroethylene (DCE), and vinyl chloride. The effluent PCE concentrations for the surfactant-modified columns were significantly lower than those for the unmodified columns (i.e., by factors of 6, 4, and 3 at pore water velocities of 0.5, 1.0, and 2.0 m/day, respectively). PCE reduction rate constants were three times higher for the modified columns relative to the unmodified columns at the three velocities. For a given column, the PCE reduction rate constant did not decrease as the pore water velocity increased from 0.5 m/day to 2.0 m/day. TCE was observed in the effluent of the modified and unmodified columns, with the concentrations for the modified columns (0.2, 0.4, and 0.7 ? M at 0.5, 1.0, and 2.0 m/day, respectively) roughly 10 times higher than those for the unmodified columns. No cis-DCE was detected in the effluent of the unmodified columns, whereas noticeable amounts (0.01-0.03 ? M) of cis-DCE were observed in the effluent of the modified columns. No trans-DCE, 1,1-DCE, or vinyl chloride was detected in the effluents of the modified or unmodified columns. Our results clearly demonstrate that the modification of zeolite/ZVI pellets with HDTMA significantly enhances PCE reduction. The enhanced PCE reduction may be due to an increased local PCE concentration in the vicinity of ZVI surface as a result of PCE sorption by the modified pellets. Our data also suggest that the PCE reduction mechanism for the modified pellets differs from that for the unmodified pellets, as seen by the much higher TCE and cis-DCE generation with the modified pellets.

  9. Effects of ultrasonic treatment on zeolite NaA synthesized from by-product silica.

    PubMed

    Vai?iukynien?, Danut?; Kantautas, Aras; Vaitkevi?ius, Vitoldas; Jakevi?ius, Leonas; Rudžionis, Žymantas; Paškevi?ius, Mantas

    2015-11-01

    The synthesis of zeolite NaA from silica by-product was carried out in the presence of 20 kHz ultrasound at room temperature. Zeolites obtained in this type of synthesis were compared to zeolites obtained by performing conventional static syntheses under similar conditions. The sonication effects on zeolite NaA synthesis were characterized by phase identification, crystallinity etc. The effects of different parameters such as crystallization time and initial materials preparation methods on the crystallinity and morphology of the synthesized zeolites were investigated. The final products were characterized by XRD and FT-IR. It was possible to obtain crystalline zeolite NaA from by-product silica in the presence of ultrasound. PMID:26186874

  10. Effects of Surface and Morphological Properties of Zeolite on Impedance Spectroscopy-Based Sensing Performance

    PubMed Central

    Zhang, Jianwei; Li, Xiaogan; White, Jeremy; Dutta, Prabir K.

    2012-01-01

    Measurement by impedance spectroscopy of the changes in intrazeolitic cation motion of pressed pellets of zeolite particles upon adsorption of dimethylmethylphosphonate (DMMP) provides a strategy for sensing DMMP, a commonly used simulant for highly toxic organophosphate nerve agents. In this work, two strategies for improving the impedance spectroscopy based sensing of DMMP on zeolites were investigated. The first one is the use of cerium oxide (CeO2) coated on the zeolite surface to neutralize acidic groups that may cause the decomposition of DMMP, and results in better sensor recovery. The second strategy was to explore the use of zeolite Y membrane. Compared to pressed pellets, the membranes have connected supercages of much longer length scales. The zeolite membranes resulted in higher sensitivity to DMMP, but recovery of the device was significantly slower as compared to pressed zeolite pellets. PMID:23201996

  11. Dispersible Exfoliated Zeolite Nanosheets and Their Application as a Selective Membrane

    SciTech Connect

    Varoon, Kumar; Zhang, Xueyi; Elyassi, Bahman; Brewer, Damien D.; Gettel, Melissa; Kumar, Sandeep; Lee, J. Alex; Maheshwari, Sundeep; Mittal, Anudha; Sung, Chun-Yi; Cococcioni, Matteo; Francis, Lorraine F.; McCormick, Alon V.; Mkhoyan, K. Andre; Tsapatsis, Michael

    2011-10-06

    Thin zeolite films are attractive for a wide range of applications, including molecular sieve membranes, catalytic membrane reactors, permeation barriers, and low-dielectric-constant materials. Synthesis of thin zeolite films using high-aspect-ratio zeolite nanosheets is desirable because of the packing and processing advantages of the nanosheets over isotropic zeolite nanoparticles. Attempts to obtain a dispersed suspension of zeolite nanosheets via exfoliation of their lamellar precursors have been hampered because of their structure deterioration and morphological damage (fragmentation, curling, and aggregation). We demonstrated the synthesis and structure determination of highly crystalline nanosheets of zeolite frameworks MWW and MFI. The purity and morphological integrity of these nanosheets allow them to pack well on porous supports, facilitating the fabrication of molecular sieve membranes.

  12. Creative Copper Crests

    ERIC Educational Resources Information Center

    Knab, Thomas

    2011-01-01

    In this article, the author discusses how to create an art activity that would link the computer-created business cards of fourth-grade students with an upcoming school-wide medieval event. Creating family crests from copper foil would be a great connection, since they, like business cards, are an individual's way to identify themselves to others.…

  13. Precursors for formation of copper selenide, indium selenide, copper indium diselenide, and/or copper indium gallium diselenide films

    SciTech Connect

    Curtis, Calvin J; Miedaner, Alexander; Van Hest, Maikel; Ginley, David S

    2014-11-04

    Liquid-based precursors for formation of Copper Selenide, Indium Selenide, Copper Indium Diselenide, and/or copper Indium Galium Diselenide include copper-organoselenides, particulate copper selenide suspensions, copper selenide ethylene diamine in liquid solvent, nanoparticulate indium selenide suspensions, and indium selenide ethylene diamine coordination compounds in solvent. These liquid-based precursors can be deposited in liquid form onto substrates and treated by rapid thermal processing to form crystalline copper selenide and indium selenide films.

  14. Copper leaching from chalcopyrite concentrates

    NASA Astrophysics Data System (ADS)

    Wang, Shijie

    2005-07-01

    Chalcopyrite (CuFeS2) is one of the most abundant copper-bearing minerals, which accounts for approximately 70 percent of the world’s known copper reserves. For more than 30 years, a significant number of processes have been developed to leach copper from chalcopyrite concentrates. These processes recover copper via hydrometallurgical leaching of the copper component of chalcopyrite concentrates, followed by solvent extraction and electrowinning. A number of demonstration plant operations have been conducted, but as of this writing none of the processes have become completely commercially operational.

  15. Permit application modifications

    SciTech Connect

    1995-11-01

    This document contains the Permit Application Modifications for the Y-12 Industrial Landfill V site on the Oak Ridge Reservation. These modifications include the assessment of stability of the proposed Landfill V under static and loading conditions. Analyses performed include the general slope stability, veneer stability of the bottom liner and cover system, and a liquefaction potential assessment of the foundation soils.

  16. Modifications of mitosis

    SciTech Connect

    1993-12-31

    Chapter 15, discusses modifications of mitosis, including endoreduplication, polyteny, endomitosis, C-mitosis, restitution, amitosis and multipolar mitoses. Apart from multipolar mitosis, all other mitotic modifications are characterized by an absent or defective spindle, and in most cases these result in the duplication of the chromosome number. 29 refs., 4 figs.

  17. Presenilin Promotes Dietary Copper Uptake

    PubMed Central

    Southon, Adam; Greenough, Mark A.; Ganio, George; Bush, Ashley I.; Burke, Richard; Camakaris, James

    2013-01-01

    Dietary copper is essential for multicellular organisms. Copper is redox active and required as a cofactor for enzymes such as the antioxidant Superoxide Dismutase 1 (SOD1). Copper dyshomeostasis has been implicated in Alzheimer’s disease. Mutations in the presenilin genes encoding PS1 and PS2 are major causes of early-onset familial Alzheimer’s disease. PS1 and PS2 are required for efficient copper uptake in mammalian systems. Here we demonstrate a conserved role for presenilin in dietary copper uptake in the fly Drosophila melanogaster. Ubiquitous RNA interference-mediated knockdown of the single Drosophila presenilin (PSN) gene is lethal. However, PSN knockdown in the midgut produces viable flies. These flies have reduced copper levels and are more tolerant to excess dietary copper. Expression of a copper-responsive EYFP construct was also lower in the midgut of these larvae, indicative of reduced dietary copper uptake. SOD activity was reduced by midgut PSN knockdown, and these flies were sensitive to the superoxide-inducing chemical paraquat. These data support presenilin being needed for dietary copper uptake in the gut and so impacting on SOD activity and tolerance to oxidative stress. These results are consistent with previous studies of mammalian presenilins, supporting a conserved role for these proteins in mediating copper uptake. PMID:23667524

  18. Mode of Bactericidal Action of Silver Zeolite and Its Comparison with That of Silver Nitrate

    PubMed Central

    Matsumura, Yoshinobu; Yoshikata, Kuniaki; Kunisaki, Shin-ichi; Tsuchido, Tetsuaki

    2003-01-01

    The properties of the bactericidal action of silver zeolite as affected by inorganic salts and ion chelators were similar to those of silver nitrate. The results suggest that the contact of the bacterial cell with silver zeolite, the consequent transfer of silver ion to the cell, and the generation of reactive oxygen species in the cell are involved in the bactericidal activity of silver zeolite. PMID:12839814

  19. Development of natural zeolites for their use in water-treatment systems.

    PubMed

    Margeta, K; Vojnovi?, B; Zabukovec Logar, N

    2011-06-01

    This paper gives an overview of research and patents concerning the use of natural zeolites in water-treatment systems in the last ten years. Furthermore, nanocomposite materials made of natural zeolites and organic and polymeric materials are also mentioned as an effective solution in water treatment. An additional emphasis is put on a variety of possibilities for further application of natural zeolite materials for environment protection and preservation. PMID:21529333

  20. Synthesis and characterization of various zeolites and study of dynamic adsorption of dimethyl methyl phosphate over them

    SciTech Connect

    Khanday, Waheed Ahmad; Majid, Sheikh Abdul; Chandra Shekar, S.; Tomar, Radha

    2013-11-15

    Graphical abstract: Thermal desorption pattern of DMMP over various zeolites (a) 1st desorption and (b) 2nd desorption. - Highlights: • Synthesis of Zeolite-A, MCM-22, Zeolite-X and Erionite by hydrothermal method. • Zeolites were characterized by using XRD, FTIR, BET, NH{sub 3}-TPD, SEM and EDS techniques. • Dynamic adsorption of DMMP on zeolites was carried out using TPD plus chemisorption system. • Thermal desorption of DMMP on zeolites was carried using the same system. - Abstract: Zeolite-A, MCM-22, Zeolite-X and Erionite were synthesized successfully under hydrothermal conditions and were characterized by X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy, scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), Brunauer–Emmett–Teller (BET) surface area analysis and thermal programmed desorption (TPD). Dynamic adsorption of dimethyl methyl phosphate (DMMP) was carried out on these zeolites. Zeolite-X having high surface area among all four zeolites shows highest adsorption capacity followed by Erionite and MCM-22 where as Zeolite-A shows the least. For all zeolites adsorption was found to be high initially and it then decreases with increase in injected volume. Then desorption pattern was analyzed which shows two types of peaks, sharp peak representing desorption of physisorbed DMMP and a broad peak representing desorption of strongly chemisorbed DMMP.

  1. Synthesis and characterization of zeolites prepared from industrial fly ash.

    PubMed

    Franus, Wojciech; Wdowin, Magdalena; Franus, Ma?gorzata

    2014-09-01

    In this paper, we present the possibility of using fly ash to produce synthetic zeolites. The synthesis class F fly ash from the Stalowa Wola SA heat and power plant was subjected to 24 h hydrothermal reaction with sodium hydroxide. Depending on the reaction conditions, three types of synthetic zeolites were formed: Na-X (20 g fly ash, 0.5 dm(3) of 3 mol?·?dm(-3) NaOH, 75 °C), Na-P1 (20 g fly ash, 0.5 dm(3) of 3 mol?·?dm(-3) NaOH, 95 °C), and sodalite (20 g fly ash, 0.8 dm(3) of 5 mol?·?dm(-3) NaOH?+?0.4 dm(3) of 3 mol?·?dm(-3) NaCl, 95 °C). As synthesized materials were characterized to obtain mineral composition (X-ray diffractometry, Scanning electron microscopy-energy dispersive spectrometry), adsorption properties (Brunauer-Emmett-Teller surface area, N2 isotherm adsorption/desorption), and ion exchange capacity. The most effective reaction for zeolite preparation was when sodalite was formed and the quantitative content of zeolite from X-ray diffractometry was 90 wt%, compared with 70 wt% for the Na-X and 75 wt% for the Na-P1. Residues from each synthesis reaction were the following: mullite, quartz, and the remains of amorphous aluminosilicate glass. The best zeolitic material as characterized by highest specific surface area was Na-X at almost 166 m(2)?·?g(-1), while for the Na-P1 and sodalite it was 71 and 33 m(2)?·?g(-1), respectively. The ion exchange capacity decreased in the following order: Na-X at 1.8 meq?·?g(-1), Na-P1 at 0.72 meq?·?g(-1), and sodalite at 0.56 meq?·?g(-1). The resulting zeolites are competitive for commercially available materials and are used as ion exchangers in industrial wastewater and soil decontamination. PMID:24838802

  2. Visible Light-Induced Catalytic Oxidation Using Zeolite Encapsulating Two Distinct Metal Complexes

    NASA Astrophysics Data System (ADS)

    Inomata, Tomohiko; Nagai, Yoshimasa; Ohata, Nayumi; Funahashi, Yasuhiro; Ozawa, Tomohiro; Masuda, Hideki

    2011-01-01

    Y-type zeolite encapsulating two distinct metal complexes has been synthesized. This zeolite contains Ru(bpy)3 (bpy = 2,2'-bipyridine) and Mn(saloph) [saloph = N,N'-bis(salicylidene)-o-phenylenediamine] as photoinducing and oxidative catalytic sites, respectively. The zeolite showed the quenching of the emission, resulting in the effective electron/energy transfer from the RuII center to the MnII center in it. The oxidation reaction of dimethyl sulfide with the zeolite has been accelerated by photoirradiation. This phenomenon indicates that the electron/energy transfer from Ru(bpy)3 units affects the oxidation reaction on Mn(saloph) units.

  3. Fabrication of silver nanoparticles doped in the zeolite framework and antibacterial activity

    PubMed Central

    Shameli, Kamyar; Ahmad, Mansor Bin; Zargar, Mohsen; Yunus, Wan Md Zin Wan; Ibrahim, Nor Azowa

    2011-01-01

    Using the chemical reduction method, silver nanoparticles (Ag NPs) were effectively synthesized into the zeolite framework in the absence of any heat treatment. Zeolite, silver nitrate, and sodium borohydride were used as an inorganic solid support, a silver precursor, and a chemical reduction agent, respectively. Silver ions were introduced into the porous zeolite lattice by an ion-exchange path. After the reduction process, Ag NPs formed in the zeolite framework, with a mean diameter of about 2.12–3.11 nm. The most favorable experimental condition for the synthesis of Ag/zeolite nanocomposites (NCs) is described in terms of the initial concentration of AgNO3. The Ag/zeolite NCs were characterized by ultraviolet-visible spectroscopy, powder X-ray diffraction, transmission electron microscopy, scanning electron microscopy, energy dispersive X-ray fluorescence, and Fourier transform infrared. The results show that Ag NPs form a spherical shape with uniform homogeneity in the particle size. The antibacterial activity of Ag NPs in zeolites was investigated against Gram-negative bacteria (ie, Escherichia coli and Shigella dysentriae) and Gram-positive bacteria (ie, Staphylococcus aureus and methicillin-resistant Staphylococcus aureus) by disk diffusion method using Mueller–Hinton agar at different sizes of Ag NPs. All of the synthesized Ag/zeolite NCs were found to have antibacterial activity. These results show that Ag NPs in the zeolite framework can be useful in different biological research and biomedical applications. PMID:21383858

  4. BTEX removal from aqueous solutions by HDTMA-modified Y zeolite.

    PubMed

    Vidal, Carla B; Raulino, Giselle S C; Barros, Allen L; Lima, Ari C A; Ribeiro, Jefferson P; Pires, Marçal J R; Nascimento, Ronaldo F

    2012-12-15

    Various technologies have been used for the treatment and remediation of areas contaminated by BTEX (benzene, toluene, ethylbenzene and xylenes), which are organic compounds that are of particular concern due to their toxicity. Potential applications of synthetic zeolites for environmental fieldwork have also been reported worldwide. In this work, a hexadecyltrimethyl ammonium (HDTMA) surfactant-modified synthetic zeolite was investigated for its efficiency in removing BTEX from aqueous solutions. Three surfactant-modified zeolites were synthesized, with amounts of surfactant corresponding to 50%, 100%, and 200% of the total cation-exchange capacity (CEC) of the synthetic zeolite Y. The results of the BTEX adsorption experiments onto both synthetic zeolite and surfactant-modified zeolites (SMZ) showed that the SMZ-100 (zeolite modified with surfactant levels at 100% of CEC) was the most efficient modified zeolite for BTEX removal. Kinetics studies indicated that the multicomponent adsorption equilibrium was reached within 6 h and followed pseudo-second-order kinetics. The Langmuir, Freundlich, Redlich-Peterson and Temkin models were used to evaluate the BTEX adsorption capacity by SMZ-100. The Temkin model was found to be suitable for all BTEX compounds in a multicomponent system. Regeneration cycles of the modified zeolite were also performed, and the results showed that the adsorbent could be used efficiently in as many as four adsorption cycles, except for benzene. PMID:22922136

  5. Adsorption of methylene blue and orange II onto unmodified and surfactant-modified zeolite.

    PubMed

    Jin, Xiaoying; Jiang, Ming-qin; Shan, Xaio-quan; Pei, Zhi-guo; Chen, Zuliang

    2008-12-15

    Adsorption of cationic methylene blue and anionic orange II onto unmodified and surfactant-modified zeolites was studied using a batch equilibration method. The effects of equilibrium time, solution pH, and sorption temperature were examined. The results suggested that 2% sodium dodecyl benzenesulfonate (SDBS)- and 3% sodium dodecyl sulfate (SDS)-modified zeolites had higher adsorption capacities for methylene blue than the unmodified zeolite, while 2% cetylpyridinium bromide hexadecyl (CPB)- and 2% hexadecylammonium bromide (HDTMA)-modified zeolites were the best adsorbents for orange II. The adsorption conditions were optimized, and the mechanisms of adsorption are briefly discussed. PMID:18848334

  6. Improved Catalysts for Heavy Oil Upgrading Based on Zeolite Y Nanoparticles Encapsulated Stable Nanoporous Host

    SciTech Connect

    Conrad Ingram; Mark Mitchell

    2007-09-30

    The objective of this project is to synthesize nanocrystals of highly acidic zeolite Y nanoclusters, encapsulate them within the channels of mesoporous (nanoporous) silicates or nanoporous organosilicates, and evaluate the 'zeolite Y/Nanoporous host' composites as catalysts for the upgrading of heavy petroleum feedstocks. In comparison to conventionally-used zeolite Y catalysts of micron size particles, the nanocrystals (< 100 nm particle size) which contain shorter path lengths, are expected to allow faster diffusion of large hydrocarbon substrates and the catalysis products within and out of the zeolite's channels and cages (<1 nm size). This is expected to significantly reduce deactivation of the catalyst and to prolong their period of reactivity. Encapsulating zeolite Y nanocrystals within the nanoporous materials is expected to protect its external surfaces and pore entrances from being blocked by large hydrocarbon substrates, since these substrates will initially be converted to small molecules by the nanoporous host (a catalyst in its own right). The project consisted of four major tasks as follows: (1) synthesis of the nanoparticles of zeolite Y (of various chemical compositions) using various techniques such as the addition of organic additives to conventional zeolite Y synthesis mixtures to suppress zeolite Y crystal growth; (2) synthesis of nanoporous silicate host materials of up to 30 nm pore diameter, using poly (alkylene oxide) copolymers which when removed will yield a mesoporous material; (3) synthesis of zeolite Y/Nanoporous Host composite materials as potential catalysts; and (4) evaluation of the catalyst for the upgrading of heavy petroleum feedstocks.

  7. Dynamic Nuclear Polarization NMR Enables the Analysis of Sn-Beta Zeolite Prepared with Natural Abundance [superscript 119]Sn Precursors

    E-print Network

    Gunther, William Robert

    The catalytic activity of tin-containing zeolites, such as Sn-Beta, is critically dependent on the successful incorporation of the tin metal center into the zeolite framework. However, synchrotron-based techniques or ...

  8. Disruption of Bacterial Cells by a Synthetic Zeolite

    PubMed Central

    Wistreich, George; Lechtman, Max D.; Bartholomew, J. W.; Bils, R. F.

    1968-01-01

    The use of a synthetic zeolite (type 4A, Union Carbide Corp., Linde Div., New York, N.Y.) in a procedure for the preparation of pure cell wall fractions proved successful for many gram-positive, gram-negative, and acid-fast bacteria, as well as for some fungi. The technique, however, was found to be limited in effectiveness for Rhodospirillum rubrum, Gaffkya tetragena, and Sarcina lutea, and not applicable to preparations of heat killed microorganisms. The possible mechanisms of zeolite action, together with the effect of the disruptive procedure on the chemical composition of cell wall fragments, were investigated also. Images Fig. 1 Fig. 2 Fig. 3 Fig. 4 Fig. 5 Fig. 6 PMID:4877657

  9. GREEN CHEMISTRY. Shape-selective zeolite catalysis for bioplastics production.

    PubMed

    Dusselier, Michiel; Van Wouwe, Pieter; Dewaele, Annelies; Jacobs, Pierre A; Sels, Bert F

    2015-07-01

    Biodegradable and renewable polymers, such as polylactic acid, are benign alternatives for petrochemical-based plastics. Current production of polylactic acid via its key building block lactide, the cyclic dimer of lactic acid, is inefficient in terms of energy, time, and feedstock use. We present a direct zeolite-based catalytic process, which converts lactic acid into lactide. The shape-selective properties of zeolites are essential to attain record lactide yields, outperforming those of the current multistep process by avoiding both racemization and side-product formation. The highly productive process is strengthened by facile recovery and practical reactivation of the catalyst, which remains structurally fit during at least six consecutive reactions, and by the ease of solvent and side-product recycling. PMID:26138977

  10. Template-free nanosized faujasite-type zeolites

    NASA Astrophysics Data System (ADS)

    Awala, Hussein; Gilson, Jean-Pierre; Retoux, Richard; Boullay, Philippe; Goupil, Jean-Michel; Valtchev, Valentin; Mintova, Svetlana

    2015-04-01

    Nanosized faujasite (FAU) crystals have great potential as catalysts or adsorbents to more efficiently process present and forthcoming synthetic and renewable feedstocks in oil refining, petrochemistry and fine chemistry. Here, we report the rational design of template-free nanosized FAU zeolites with exceptional properties, including extremely small crystallites (10-15 nm) with a narrow particle size distribution, high crystalline yields (above 80%), micropore volumes (0.30 cm3 g-1) comparable to their conventional counterparts (micrometre-sized crystals), Si/Al ratios adjustable between 1.1 and 2.1 (zeolites X or Y) and excellent thermal stability leading to superior catalytic performance in the dealkylation of a bulky molecule, 1,3,5-triisopropylbenzene, probing sites mostly located on the external surface of the nanosized crystals. Another important feature is their excellent colloidal stability, which facilitates a uniform dispersion on supports for applications in catalysis, sorption and thin-to-thick coatings.

  11. Double rotation NMR studies of zeolites and aluminophosphate molecular sieves

    SciTech Connect

    Jelinek, R. |

    1993-07-01

    Goal is to study the organization and structures of guest atoms and molecules and their reactions on internal surfaces within pores of zeolites and aluminophosphate molecular sieves. {sup 27}Al and {sup 23}Na double rotation NMR (DOR) is used since it removes the anisotropic broadening in NMR spectra of quadrupolar nuclei, thus increasing resolution. This work concentrates on probing aluminum framework atoms in aluminophosphate molecular sieves and sodium extra framework cations in porous aluminosilicates. In aluminophosphates, ordering and electronic environments of the framework {sup 27}Al nuclei are modified upon adsorption of water molecules within the channels; a relation is sought between the sieve channel topology and the organization of adsorbed water, as well as the interaction between the Al nuclei and the water molecules. Extra framework Na{sup +} cations are directly involved in adsorption processes and reactions in zeolite cavities.

  12. Application of zeolites for radium removal from mine water.

    PubMed

    Cha?upnik, Stanis?aw; Franus, Wojciech; Wysocka, Ma?gorzata; Gzyl, Grzegorz

    2013-11-01

    For removal of radium from saline waters in Upper Silesian mines, several methods of purification have been developed. The most efficient one is based on application of barium chloride, which was implemented in full technical scale in two Polish coal mines several years ago. Very good results of purification have been achieved-the removal efficiency exceeding 95% of the initial activity. Another possibility for the removal of different ions from salty waters and brines is the application of zeolites. We found that technique as a very promising method for removal of not only radium isotopes from mine waters but also other ions (barium, iron, manganese). Treatment of several various water samples has been done to assess the removal efficiency for natural radionuclides. Preliminary results show very good effects for radium isotopes as well as for barium ions. In the paper, a short description of laboratory results of the purification of mine waters with application of synthetic zeolites is presented. PMID:23881589

  13. Shape-selective zeolite catalysis for bioplastics production

    NASA Astrophysics Data System (ADS)

    Dusselier, Michiel; Van Wouwe, Pieter; Dewaele, Annelies; Jacobs, Pierre A.; Sels, Bert F.

    2015-07-01

    Biodegradable and renewable polymers, such as polylactic acid, are benign alternatives for petrochemical-based plastics. Current production of polylactic acid via its key building block lactide, the cyclic dimer of lactic acid, is inefficient in terms of energy, time, and feedstock use. We present a direct zeolite-based catalytic process, which converts lactic acid into lactide. The shape-selective properties of zeolites are essential to attain record lactide yields, outperforming those of the current multistep process by avoiding both racemization and side-product formation. The highly productive process is strengthened by facile recovery and practical reactivation of the catalyst, which remains structurally fit during at least six consecutive reactions, and by the ease of solvent and side-product recycling.

  14. Wastewater treatment in production of MgA zeolite

    SciTech Connect

    Barsukov, V.V.; Akopyants, T.V.; Rudova, S.A.; Shumovskii, A.V.

    1986-09-01

    This paper reports the development of zero-waste technology for treatment of chloride waste formed in the manufacture of MgA microbead zeolite, based on the method and flow plan used in treating similar wastes formed in the manufacture of bead zeolite. The first crystals of sodium chloride appeared at a magnesium chloride concentration of 8-9% by weight. With a magnesium chloride concentration of 35% by weight, at 50 C, the sodium chloride was almost completely precipitated. Under these conditions, the magnesium chloride did not precipitate. Sodium chloride crystals were washed with water in order to obtain a commercial product meeting the requirements of the specification Tu 6-12-33-78. This product is recommended for use in regenerating cation exchange filters in thermal power plants.

  15. Inelastic X-ray Scattering Studies of Zeolite Collapse

    SciTech Connect

    Greaves, G. Neville; Kargl, Florian; Ward, David; Holliman, Peter; Meneau, Florian

    2009-01-29

    In situ inelastic x-ray scattering (IXS) experiments have been used to probe heterogeneity and deformability in zeolte Y as this thermally collapses to a high density amorphous (HDA) aluminosilicate phase. The Landau-Placzek ratio R{sub LP} falls slowly as amorphisation advances, increasing in the later stages of collapse clearly showing how homogeneity improves non-linearly--behaviour linked closely with the decline in molar volume V{sub Molar}. The Brillouin frequency {omega}{sub Q} also decreases with amorphisation in a similar fashion, signifying a non-uniform decrease in the speed of sound v{sub l}. All of these changes with zeolite amorphisation infer formation of an intermediate low density amorphous (LDA) phase. This low entropy or 'perfect glass' has mechanical properties which are closer to the zeolite rather to the HDA glass--notably a very small value of Poisson's Ratio signifying unusually low resistance to deformation.

  16. Alkalinity and formation of zeolites in saline alkaline lakes.

    PubMed

    Mariner, R H; Surdam, R C

    1970-11-27

    The solubility of rhyolitic glass increases with increasing alkalinity, whereas the ratio of silicon to aluminum decreases with increasing alkalinity. The strong correlation observed between alkalinity and zeolite mineralogy in saline, alkaline lakes is thought to be a function of this relationship between pH and the Si/Al ratio. It is suggested that this function is a result of the reaction between silicic glass and alkaline solution whereby (i) a gel forms, whose Si/Al ratio is controlled by the Si/Al ratio of the solution, and (ii) a zeolite forms from the gel, whose Si/Al ratio is, in turn, controlled by the composition of the gel. PMID:17834613

  17. Negative Poisson's ratios in siliceous zeolite MFI-silicalite.

    PubMed

    Sanchez-Valle, Carmen; Lethbridge, Zoe A D; Sinogeikin, Stanislav V; Williams, Jennifer J; Walton, Richard I; Evans, Kenneth E; Bass, Jay D

    2008-05-14

    Brillouin scattering measurements of the single-crystal elastic properties of the as-made zeolite silicalite mid R:(C(3)H(7))(4)NFmid R:(4)[Si(96)O(192)]-MFI provides the first experimental evidence for on-axis negative Poisson's ratios (auxeticity) in a synthetic zeolite structure. MFI laterally contracts when compressed and laterally expands when stretched along x(1) and x(2) directions in the (001) plane (nu(12)=-0.061, nu(21)=-0.051). The aggregate Poisson's ratio of MFI, although positive, has an anomalously low value nu=0.175(3) compared to other silicate materials. These results suggest that the template-free MFI-silicalite [Si(96)O(192)] might have potential applications as tunable sieve where molecular discriminating characteristics are adjusted by application of stress along specific axes. PMID:18532822

  18. Computational studies of Bronsted acid sites in zeolites

    SciTech Connect

    Curtiss, L.A.; Iton, L.E.; Zygmunt, S.A.

    1995-01-01

    The authors have performed high-level ab initio calculations using both Hartree-Fock (HF) and Moller-Plesset perturbation theory (MP2) to study the geometry and energetics of the adsorption complex involving H{sub 2}O and the Bronsted acid site in the zeolite H-ZSM-5. In these calculations, which use aluminosilicate cluster models for the zeolite framework with as many a 28 T atoms (T = Si, Al), we included geometry optimization in the local vicinity of the acid site at the HF/6-31G(d) level of theory, and have calculated corrections for zero-point energies, extensions for zero-point energies, extensions to higher basis sets, and the influence of electron correlation. Results for the adsorption energy and geometry of this complex are reported and compared with previous theoretical and experimental values.

  19. Generalized statistical model for multicomponent adsorption equilibria on zeolites

    SciTech Connect

    Rota, R.; Gamba, G.; Paludetto, R.; Carra, S.; Morbidelli, M. )

    1988-05-01

    The statistical thermodynamic approach to multicomponent adsorption equilibria on zeolites has been extended to nonideal systems, through the correction of cross coefficients characterizing the interaction between unlike molecules. Estimation of the model parameters requires experimental binary equilibrium data. Comparisons with the classical model based on adsorbed solution theory are reported for three nonideal ternary systems. The two approaches provide comparable results in the simulation of binary and ternary adsorption equilibrium data at constant temperature and pressure.

  20. Dehydration of cyclohexanol as a test reaction for zeolite acidity

    SciTech Connect

    Karge, H.G.; Kosters, H.; Wada, Y.

    1984-01-01

    Dehydration of cyclohexanol was investigated using a fixed-bed continuous flow reactor with acidic mordenite-type, clinoptilolite-type, and faujasite-type (Y) zeolites as catalysts. The surface acidity of the catalysts employed was studied by IR using pyridine or 2,6-di-tert. butylpyridine as probe molecules. A correlation between the acidity and the rates of dehydration was clearly shown.

  1. Epitaxially grown layered MFI-bulk MFI hybrid zeolitic materials.

    PubMed

    Kim, Wun-gwi; Zhang, Xueyi; Lee, Jong Suk; Tsapatsis, Michael; Nair, Sankar

    2012-11-27

    The synthesis of hybrid zeolitic materials with complex micropore-mesopore structures and morphologies is an expanding area of recent interest for a number of applications. Here we report a new type of hybrid zeolite material, composed of a layered zeolite material grown epitaxially on the surface of a bulk zeolite material. Specifically, layered (2-D) MFI sheets were grown on the surface of bulk MFI crystals of different sizes (300 nm and 10 ?m), thereby resulting in a hybrid material containing a unique morphology of interconnected micropores (?0.55 nm) and mesopores (?3 nm). The structure and morphology of this material, referred to as a "bulk MFI-layered MFI" (BMLM) material, was elucidated by a combination of XRD, TEM, HRTEM, SEM, TGA, and N(2) physisorption techniques. It is conclusively shown that epitaxial growth of the 2-D layered MFI sheets occurs in at least two principal crystallographic directions of the bulk MFI crystal and possibly in the third direction as well. The BMLM material combines the properties of bulk MFI (micropore network and mechanical support) and 2-D layered MFI (large surface roughness, external surface area, and mesoporosity). As an example of the uses of the BMLM material, it was incorporated into a polyimide and fabricated into a composite membrane with enhanced permeability for CO(2) and good CO(2)/CH(4) selectivity for gas separations. SEM-EDX imaging and composition analysis showed that the polyimide and the BMLM interpenetrate into each other, thereby forming a well-adhered polymer/particle microstructure, in contrast with the defective interfacial microstructure obtained using bare MFI particles. Analysis of the gas permeation data with the modified Maxwell model also allows the estimation of the effective volume of the BMLM particles, as well as the CO(2) and CH(4) gas permeabilities of the interpenetrated layer at the BMLM/polyimide interface. PMID:23045956

  2. Novel Zeolitic Imidazolate Framework/Polymer Membranes for Hydrogen Separations in Coal Processing

    SciTech Connect

    Musselman, Inga H.

    2013-01-31

    Nanoparticles of zeolitic imidazolate frameworks and other related hybrid materials were prepared by modifying published synthesis procedures by introducing bases, changing stoichiometric ratios, or adjusting reaction conditions. These materials were stable at temperatures >300 °C and were compatible with the polymer matrices used to prepare mixed-matrix membranes (MMMs). MMMs tested at 300 °C exhibited a >30 fold increase in permeability, compared to those measured at 35 °C, while maintaining H{sub 2}/CO{sub 2} selectivity. Measurements at high pressure (up to 30 atm) and high temperature (up to 300 °C) resulted in an increase in gas flux across the membrane with retention of selectivity. No variations in permeability were observed at high pressures at either 35 or 300 °C. CO{sub 2}-induced plasticization was not observed for Matrimid®, VTEC, and PBI polymers or their MMMs at 30 atm and 300 °C. Membrane surface modification by cross-linking with ethylenediamine resulted in an increase in H{sub 2}/CO{sub 2} selectivity at 35 °C. Spectrometric analysis showed that the cross-linking was effective to temperatures <150 °C. At higher temperatures, the cross-linked membranes exhibit a H2/CO2 selectivity similar to the uncrosslinked polymer.

  3. Development of Zeolite Nonwoven for the Adsorption of Radioactive Cesium - 13288

    SciTech Connect

    Murao, Ayako; Nakai, Tomonori; Mimura, Hitoshi; Miura, Teruo; Aoyama, Yoshihito

    2013-07-01

    The zeolite nonwoven fabric produced by TDS (Totally Dry System) process has some advantages such as the control of zeolite content, flexibility, strength and water-resistant property depending on the purpose. Hence the zeolite nonwoven fabric is expected for the application in various fields of the decontamination of Cs-contaminated water. In this study, Cs adsorption properties of zeolite nonwoven fabrics were examined by batch experiments, and the radiation stability, thermal stability and chemical durability were evaluated. As for batch adsorption properties, relatively large uptake rate of Cs{sup +} was obtained; the uptake equilibrium attained within 20 min and the uptake (%) was above 95%. The differences in zeolite content had no effects on the Cs{sup +} uptake (%). The uptake (%) of Cs{sup +} in seawater was slightly lowered compared to that in the presence of HNO{sub 3}. The uptake (%) of Cs{sup +} in seawater was estimated to be above 90% after 2 h-shaking, indicating the considerable enhancement of uptake rate compared to the conventional granular zeolites. The uptake (%) of Cs{sup +} for the zeolite high content type was estimated to be above 99% by using {sup 137}Cs tracer. As for the comparison of sealing treatment, the uptake (%) for the zeolite sheet treated with edge sealing was larger than that with rapping treatment. The uptake (%) for the zeolite sheet (zeolite high content type) was estimated to be about 95%, which is independent of sealing treatment and NaOH concentration. As for the stability, the surface morphology and the structure of zeolite sheet were not altered by the treatment with acid and alkaline solutions under the experimental conditions. The zeolite sheets were also stable after {sup 60}Co-? ray irradiation up to 7.01x10{sup 6} R. On the other hand, color change for both fiber and zeolite and the shrinkage of the fiber were observed after heat treatment at 150 deg. C for 2 h. Thus the considerable enhancement of adsorption properties was observed by using zeolite nonwoven fabrics compared to the conventional granular zeolites. (authors)

  4. Correlations for Adsorption of Oxygenates onto Zeolites from Aqueous Solutions

    SciTech Connect

    Mallon, Elizabeth E.; Babineau, Ian J.; Kranz, Joshua I.; Guefrachi, Yasmine; Siepmann, J. Ilja; Bhan, Aditya; Tsapatsis, Michael

    2011-10-06

    Henry’s constants (K{sub ads}) for adsorption of C? polyfunctional molecules onto zeolites from aqueous solutions at 278 K were obtained and compared with the octanol–water partition coefficients, K{sub ow}, which were calculated using the prevalent ClogP group contribution method. K{sub ads} increases linearly with K{sub ow} for these adsorbates on H–ZSM-5 (MFI), FAU, BEA, and ITQ-1 (MWW). K{sub ads} values for C?–C? diol adsorption at 278 K are also linearly correlated with K{sub ow} regardless of interactions in the bulk phase as measured by the solution activity coefficient. Exceptions to the correlation established between K{sub ads} and K{sub ow} are the adsorption of 1,2,?-triols with carbon number greater than three on H–ZSM-5 and adsorption of all oxygenates studied on FER, which we postulate to be due to the effect of changing adsorption configuration with adsorbate/zeolite structure which cannot be captured by K{sub ow} alone. These results enable the prediction of separation selectivities of biomass-derived compounds on zeolite adsorbents.

  5. Zeolites on Mars: Possible environmental indicators in soils and sediments

    NASA Technical Reports Server (NTRS)

    Ming, D. W.; Gooding, J. L.

    1988-01-01

    Weathering products should serve as indicators of weathering environments and may provide the best evidence of the nature of climate change on Mars. No direct mineralogical measurements of Martian regolith were performed by the Viking missions, but the biology and X-ray fluorescence experiments provided some information on the physiochemical properties of Martian regolith. Most post-Viking studies of candidate weathering products have emphasized phyllosilicates and Fe-oxides; zeolites are potentially important, but overlooked, candidate Martian minerals. Zeolites would be important on Mars for three different reasons. First, they are major sinks of atmospheric gases and, per unit mass, are stronger and more efficient sorbents than are phyllosilicates. Secondly, they can be virtually unique sorbents and shelters for organic compounds and possible catalysts for organic-based reactions. Finally, their exchangeable ions are good indicators of the chemical properties of solutions with which they have communicated. Accordingly, the search for information on past compositions of the Martian atmosphere and hydrosphere should find zeolites to be rich repositories.

  6. CO2 adsorption in amine-grafted zeolite 13X

    NASA Astrophysics Data System (ADS)

    Bezerra, Diôgo P.; Silva, Francisco W. M. da; Moura, Pedro A. S. de; Sousa, Allyson G. S.; Vieira, Rodrigo S.; Rodriguez-Castellon, Enrique; Azevedo, Diana C. S.

    2014-09-01

    The adsorption of CO2 on Zeolite 13X functionalized with amino groups was studied. Adsorbent functionalization was carried out by grafting with different loads of monoethanolamine (MEA). The adsorbents were characterized by N2 adsorption/desorption isotherms at 77 K, x-ray diffraction, TGA, in situ FTIR, XPS and adsorption microcalorimetry. CO2 isotherms were studied in a gravimetric device up to 10 bar at 298 and 348 K. It was found that increasing loads of amine to the adsorbent tend to reduce micropore volume of the resulting adsorbents by pore blocking with MEA. There is experimental evidence that part of the loaded MEA is effectively covalently bonded to the zeolitic structure, whereas there is also physisorbed excess MEA which will eventually be desorbed by raising the temperature beyond MEA boiling point. Heats of adsorption at nearly zero coverage indicate that some of the adsorbed CO2 reacts with available amino groups, which agrees with the finding that the adsorption capacity increases with increasing temperature for the modified zeolite with the highest MEA load.

  7. Synthetic zeolites and other microporous oxide molecular sieves.

    PubMed

    Sherman, J D

    1999-03-30

    Use of synthetic zeolites and other microporous oxides since 1950 has improved insulated windows, automobile air-conditioning, refrigerators, air brakes on trucks, laundry detergents, etc. Their large internal pore volumes, molecular-size pores, regularity of crystal structures, and the diverse framework chemical compositions allow "tailoring" of structure and properties. Thus, highly active and selective catalysts as well as adsorbents and ion exchangers with high capacities and selectivities were developed. In the petroleum refining and petrochemical industries, zeolites have made possible cheaper and lead-free gasoline, higher performance and lower-cost synthetic fibers and plastics, and many improvements in process efficiency and quality and in performance. Zeolites also help protect the environment by improving energy efficiency, reducing automobile exhaust and other emissions, cleaning up hazardous wastes (including the Three Mile Island nuclear power plant and other radioactive wastes), and, as specially tailored desiccants, facilitating the substitution of new refrigerants for the ozone-depleting chlorofluorocarbons banned by the Montreal Protocol. PMID:10097059

  8. Sonochemical synthesis of zeolite NaP from clinoptilolite.

    PubMed

    Behin, Jamshid; Kazemian, Hossein; Rohani, Sohrab

    2016-01-01

    In the present work, natural clinoptilolite was converted to zeolite NaP using ultrasonic energy, in which the transformation time shortened remarkably. The effect of post-synthesis treatment using conventional hydrothermal was also investigated. The synthesized powders were characterized by XRD, TGA/DTA, SEM, and PSD analysis. The results showed that, increasing the sonication time (energy) has no significant effect on the product's morphology. The crystallinity of the synthesized samples increased slightly with increasing sonication time, but their yield remained relatively unchanged. Furthermore, post-synthesis hydrothermal treatment showed very little influence on properties of the final product. Because the ultrasonic irradiation creates acoustic cavitation cracks on the surface structure of clinoptilolite particulates and increases the concentration of soluble alumino-silicate species, which favors the prevailing super-saturation, crystallization and crystal growth of zeolite NaP happen faster. The particles of zeolite NaP synthesized by ultrasonic irradiation consist of small crystallites of uniform size. PMID:26341462

  9. Synthetic zeolites and other microporous oxide molecular sieves

    PubMed Central

    Sherman, John D.

    1999-01-01

    Use of synthetic zeolites and other microporous oxides since 1950 has improved insulated windows, automobile air-conditioning, refrigerators, air brakes on trucks, laundry detergents, etc. Their large internal pore volumes, molecular-size pores, regularity of crystal structures, and the diverse framework chemical compositions allow “tailoring” of structure and properties. Thus, highly active and selective catalysts as well as adsorbents and ion exchangers with high capacities and selectivities were developed. In the petroleum refining and petrochemical industries, zeolites have made possible cheaper and lead-free gasoline, higher performance and lower-cost synthetic fibers and plastics, and many improvements in process efficiency and quality and in performance. Zeolites also help protect the environment by improving energy efficiency, reducing automobile exhaust and other emissions, cleaning up hazardous wastes (including the Three Mile Island nuclear power plant and other radioactive wastes), and, as specially tailored desiccants, facilitating the substitution of new refrigerants for the ozone-depleting chlorofluorocarbons banned by the Montreal Protocol. PMID:10097059

  10. Molecular simulation studies of water physisorption in zeolites.

    PubMed

    Di Lella, Angela; Desbiens, Nicolas; Boutin, Anne; Demachy, Isabelle; Ungerer, Philippe; Bellat, Jean-Pierre; Fuchs, Alain H

    2006-12-14

    We report a series of Grand Canonical Monte Carlo simulations of water adsorption in NaY and NaX faujasite, as well as in silicalite-1. Computed adsorption isotherms and heats of adsorption were in good agreement with the available experiments. The existence of cyclic water hexamers in NaX located in the 12-ring windows, recently disclosed by neutron diffraction experiments (Hunger et al., J. Phys. Chem. B, 2006, 110, 342-353) was reproduced in our simulations. Interestingly enough, such cyclic hexamer clusters were also observed in the case of NaY, in which no stabilizing cation is present in the 12-ring window. We also report cation redistribution upon water adsorption for sodium faujasite with varying cation contents (Si ratio Al ratio in the range 1.53-3). A simple and transferable forcefield was used, that enabled to reproduce the different aspects of water physisorption in stable zeolites. The high pressure water condensation in hydrophobic silicalite-1 was reproduced without any parameter readjustment. The method and forcefield used here should be useful for engineering oriented applications such as the prediction of multi-component mixture adsorptive separations in various stable zeolites. It allows to address the issue of the effect of the small amounts of water that are almost inevitably present in zeolite-based separation processes. PMID:17119646

  11. Core-shell strain structure of zeolite microcrystals

    NASA Astrophysics Data System (ADS)

    Cha, Wonsuk; Jeong, Nak Cheon; Song, Sanghoon; Park, Hyun-Jun; Thanh Pham, Tung Cao; Harder, Ross; Lim, Bobae; Xiong, Gang; Ahn, Docheon; McNulty, Ian; Kim, Jungho; Yoon, Kyung Byung; Robinson, Ian K.; Kim, Hyunjung

    2013-08-01

    Zeolites are crystalline aluminosilicate minerals featuring a network of 0.3-1.5-nm-wide pores, used in industry as catalysts for hydrocarbon interconversion, ion exchangers, molecular sieves and adsorbents. For improved applications, it is highly useful to study the distribution of internal local strains because they sensitively affect the rates of adsorption and diffusion of guest molecules within zeolites. Here, we report the observation of an unusual triangular deformation field distribution in ZSM-5 zeolites by coherent X-ray diffraction imaging, showing the presence of a strain within the crystal arising from the heterogeneous core-shell structure, which is supported by finite element model calculation and confirmed by fluorescence measurement. The shell is composed of H-ZSM-5 with intrinsic negative thermal expansion whereas the core exhibits a different thermal expansion behaviour due to the presence of organic template residues, which usually remain when the starting materials are insufficiently calcined. Engineering such strain effects could have a major impact on the design of future catalysts.

  12. The pitting corrosion of copper

    SciTech Connect

    Edwards, M. . Dept. of Civil Engineering); Ferguson, J.F. . Dept. of Civil Engineering); Reiber, S.H. )

    1994-07-01

    Some current theories of copper pitting are contradicted by practical experience. Although it has been theorized that chloride initiates copper pitting attack, simple experiments show that the presence of chloride ion actually tends to decrease the likelihood that pitting will occur. In contrast, sulfate plays no role in pitting theory, yet sulfate has consistently demonstrated a propensity to initiate and propagate copper pitting. New theories are required to reconcile pitting theory and practical observation in order to allow the rational mitigation of copper pitting problems. In addition, the presence of natural organic matter (NOM) in water supplies prevents or inhibits certain copper corrosion problems. As a result, recent efforts to remove NOM as a means of controlling disinfection by-products may lead to increased copper corrosion problems.

  13. Fly ash from a Mexican mineral coal. II. Source of W zeolite and its effectiveness in arsenic (V) adsorption.

    PubMed

    Medina, Adriana; Gamero, Prócoro; Almanza, José Manuel; Vargas, Alfredo; Montoya, Ascención; Vargas, Gregorio; Izquierdo, María

    2010-09-15

    Coal-fired plants in Coahuila (Mexico) produce highly reactive fly ash (MFA), which is used in a one-step process as a raw material in producing zeolite. We explored two routes in the synthesis of zeolite: (a) direct MFA zeolitization, which resulted in the formation of W zeolite with KOH and analcime with NaOH and (b) a MFA fusion route, which resulted in the formation of zeolite W or chabazite with KOH and zeolite X or P with NaOH. No residual crystalline phases were present. When LiOH was employed, ABW zeolite with quartz and mullite were obtained. For both zeolitization routes, the nature of the alkali (KOH, NaOH, LiOH), the alkali/MFA ratio (0.23-1.46), and the crystallization temperature and time (90-175 degrees C; 8-24 h) were evaluated. Additionally, the effect of temperature and time on MFA fusion was studied. W zeolite was obtained by both zeolitization methods. The direct route is preferred because it is a straightforward method using soft reaction conditions that results in a high yield of low cost zeolites with large crystal agglomerates. It was demonstrated that aluminum modified W zeolite has the ability to remove 99% of the arsenic (V) from an aqueous solution of Na(2)HAsO(4).7H(2)O originally containing 740 ppb. PMID:20537461

  14. Chemical modification of silicene

    NASA Astrophysics Data System (ADS)

    Wang, Rong; Xu, Ming-Sheng; Pi, Xiao-Dong

    2015-08-01

    Silicene is a two-dimensional (2D) material, which is composed of a single layer of silicon atoms with sp2-sp3 mixed hybridization. The sp2-sp3 mixed hybridization renders silicene excellent reactive ability, facilitating the chemical modification of silicene. It has been demonstrated that chemical modification effectively enables the tuning of the properties of silicene. We now review all kinds of chemical modification methods for silicene, including hydrogenation, halogenation, organic surface modification, oxidation, doping and formation of 2D hybrids. The effects of these chemical modification methods on the geometrical, electronic, optical, and magnetic properties of silicene are discussed. The potential applications of chemically modified silicene in a variety of fields such as electronics, optoelectronics, and magnetoelectronics are introduced. We finally envision future work on the chemical modification of silicene for further advancing the development of silicene. Project supported by the National Basic Program of China (Grant No. 2013CB632101), the National Natural Science Foundation of China (Grant Nos. 61222404 and 61474097), and the Fundamental Research Funds for the Central Universities of China (Grant No. 2014XZZX003-09).

  15. Oxidation Mechanism of Copper Selenide

    NASA Astrophysics Data System (ADS)

    Taskinen, Pekka; Patana, Sonja; Kobylin, Petri; Latostenmaa, Petri

    2014-09-01

    The oxidation mechanism of copper selenide was investigated at deselenization temperatures of copper refining anode slimes. The isothermal roasting of synthetic, massive copper selenide in flowing oxygen and oxygen - 20% sulfur dioxide mixtures at 450-550 °C indicate that in both atmospheres the mass of Cu2Se increases as a function of time, due to formation of copper selenite as an intermediate product. Copper selenide oxidises to copper oxides without formation of thick copper selenite scales, and a significant fraction of selenium is vaporized as SeO2(g). The oxidation product scales on Cu2Se are porous which allows transport of atmospheric oxygen to the reaction zone and selenium dioxide vapor to the surrounding gas. Predominance area diagrams of the copper-selenium system, constructed for selenium roasting conditions, indicate that the stable phase of copper in a selenium roaster gas with SO2 is the sulfate CuSO4. The cuprous oxide formed in decomposition of Cu2Se is further sulfated to CuSO4.

  16. Zeolite-b grown epitaxially on SSZ-31 nanofibers Sankar Nair,a Luis A. Villaescusa,b Miguel A. Camblor*b and Michael Tsapatsis*a

    E-print Network

    Nair, Sankar

    Zeolite-b grown epitaxially on SSZ-31 nanofibers Sankar Nair,a Luis A. Villaescusa,b Miguel A and characterization of an epitaxial growth of zeolite b on SSZ-31 nanofibers is described, and a structural model of the interface between the two zeolites is pro- posed. Zeolite crystals in the form of nanofibers have several

  17. 1130 J.Am. Chem. SOC.1989, I l l , 1130-1131 in zeolite-Y.I6 [Note pentamethylbenzene with u = 7.15 A passes

    E-print Network

    Boxer, Steven G.

    1130 J.Am. Chem. SOC.1989, I l l , 1130-1131 in zeolite-Y.I6 [Note pentamethylbenzene with u = 7 is also observed with zeolite-)zeolite- Y)" but not with the more constricted 4.2 8, aperture in zeolite-A'* or with completely amorphous silica alumina. Owing to the wide

  18. Experiments for the Undergraduate Laboratory that Illustrate the Size-Exclusion Properties of Zeolite Molecular Sieves

    ERIC Educational Resources Information Center

    Cooke, Jason; Henderson, Eric J.

    2009-01-01

    Experiments are presented that demonstrate the size-exclusion properties of zeolites and reveal the reason for naming zeolites "molecular sieves". If an IR spectrometer is available, the adsorption or exclusion of alcohols of varying sizes from dichloromethane or chloroform solutions can be readily demonstrated by monitoring changes in the…

  19. Separation and recovery of tritium from hydrogen by means of cryogenic adsorption on zeolites

    SciTech Connect

    Alexeyev, I.A.; Trenin, V.D.

    1993-12-31

    Accomplished research shows the perspectiveness of the use of adsorption on zeolites for separation of tritiated mixtures of fusion plants, as well as for evacuation and transport of these mixtures. Tritium separation and recovery from hydrogen can be organized in a counterflow column with stationary zeolite bed.

  20. A zeolite family with expanding structural complexity and embedded isoreticular structures.

    PubMed

    Guo, Peng; Shin, Jiho; Greenaway, Alex G; Min, Jung Gi; Su, Jie; Choi, Hyun June; Liu, Leifeng; Cox, Paul A; Hong, Suk Bong; Wright, Paul A; Zou, Xiaodong

    2015-08-01

    The prediction and synthesis of new crystal structures enable the targeted preparation of materials with desired properties. Among porous solids, this has been achieved for metal-organic frameworks, but not for the more widely applicable zeolites, where new materials are usually discovered using exploratory synthesis. Although millions of hypothetical zeolite structures have been proposed, not enough is known about their synthesis mechanism to allow any given structure to be prepared. Here we present an approach that combines structure solution with structure prediction, and inspires the targeted synthesis of new super-complex zeolites. We used electron diffraction to identify a family of related structures and to discover the structural 'coding' within them. This allowed us to determine the complex, and previously unknown, structure of zeolite ZSM-25 (ref. 8), which has the largest unit-cell volume of all known zeolites (91,554 cubic ångströms) and demonstrates selective CO2 adsorption. By extending our method, we were able to predict other members of a family of increasingly complex, but structurally related, zeolites and to synthesize two more-complex zeolites in the family, PST-20 and PST-25, with much larger cell volumes (166,988 and 275,178 cubic ångströms, respectively) and similar selective adsorption properties. Members of this family have the same symmetry, but an expanding unit cell, and are related by hitherto unrecognized structural principles; we call these family members embedded isoreticular zeolite structures. PMID:26176918

  1. The recyclable synthesis of hierarchical zeolite SAPO-34 with excellent MTO catalytic performance.

    PubMed

    Xi, Dongyang; Sun, Qiming; Chen, Xiaoxin; Wang, Ning; Yu, Jihong

    2015-08-01

    A facile and green route has been developed for the synthesis of hierarchical zeolite catalysts by recycling of waste mother-liquors. After three recycles of mother-liquors, the obtained hierarchical SAPO-34 zeolites retain high crystallinity, texture properties, and acidity, as well as excellent MTO catalytic performance as compared to the initially prepared catalysts. PMID:26121259

  2. Removal of ammonium from swine wastewater by zeolite combined with chlorination for regeneration.

    PubMed

    Huang, Haiming; Yang, Liping; Xue, Qiang; Liu, Jiahui; Hou, Li; Ding, Li

    2015-09-01

    This study investigated a process using ammonium ion (NH4(+)) exchange on zeolite in combination with chlorination regeneration for the safe treatment of simulated swine wastewater. Two stages i) 120-min zeolite ion-exchange and ii) 10-min exchanged zeolite regeneration facilitated NH4(+) ion removal from wastewater. Solution pH, contact time, adsorbent dosage, and competitive cations were the significant factors influencing the entire process. The effect of competitive cations on NH4(+) removal effectively followed the order of preference as Na(+)>K(+)>Ca(2+)>Mg(2+) at equivalent concentrations. The chlorination method experimentally removed approximately 99% of the NH4(+) exchanged on the zeolite, without remaining NH4(+) in the regeneration solution. Our analysis revealed that, in this process, the NH4(+) exchanged on the zeolite was first replaced by Na(+) and then oxidized to nitrogen gas. Reuse of the regenerated zeolite (GZ) indicated that the removal efficiency of NH4(+) ions was equal to that of the fresh zeolite modified with NaCl. Results of kinetic analysis revealed that the NH4(+) exchange on the GZ followed the pseudo-second-order model and the intraparticle diffusion model only for the first 60 min. The ion-exchange isotherm results demonstrated that the Langmuir model provided a slightly more consistent fit to the equilibrium data as compared with the Freundlich model. Repetitive experimental results confirmed that the proposed zeolite recycling process was stable and usable in simulated swine wastewater treatment. PMID:26143500

  3. One-pot synthesized hierarchical zeolite supported metal nanoparticles for highly efficient biomass conversion.

    PubMed

    Wang, Darui; Ma, Bing; Wang, Bo; Zhao, Chen; Wu, Peng

    2015-10-21

    Hierarchically porous zeolite supported metal nanoparticles are successfully prepared through a base-assisted chemoselective interaction between the silicon species on the zeolite crystal surface and metal salts, in which in situ construction of mesopores and high dispersion of metal species are realized simultaneously. PMID:26361087

  4. A zeolite family with expanding structural complexity and embedded isoreticular structures

    NASA Astrophysics Data System (ADS)

    Guo, Peng; Shin, Jiho; Greenaway, Alex G.; Min, Jung Gi; Su, Jie; Choi, Hyun June; Liu, Leifeng; Cox, Paul A.; Hong, Suk Bong; Wright, Paul A.; Zou, Xiaodong

    2015-08-01

    The prediction and synthesis of new crystal structures enable the targeted preparation of materials with desired properties. Among porous solids, this has been achieved for metal-organic frameworks, but not for the more widely applicable zeolites, where new materials are usually discovered using exploratory synthesis. Although millions of hypothetical zeolite structures have been proposed, not enough is known about their synthesis mechanism to allow any given structure to be prepared. Here we present an approach that combines structure solution with structure prediction, and inspires the targeted synthesis of new super-complex zeolites. We used electron diffraction to identify a family of related structures and to discover the structural `coding' within them. This allowed us to determine the complex, and previously unknown, structure of zeolite ZSM-25 (ref. 8), which has the largest unit-cell volume of all known zeolites (91,554 cubic ångströms) and demonstrates selective CO2 adsorption. By extending our method, we were able to predict other members of a family of increasingly complex, but structurally related, zeolites and to synthesize two more-complex zeolites in the family, PST-20 and PST-25, with much larger cell volumes (166,988 and 275,178 cubic ångströms, respectively) and similar selective adsorption properties. Members of this family have the same symmetry, but an expanding unit cell, and are related by hitherto unrecognized structural principles; we call these family members embedded isoreticular zeolite structures.

  5. Solvation and acid strength effects on catalysis by faujasite zeolites Rajamani Gounder a

    E-print Network

    Iglesia, Enrique

    Solvation and acid strength effects on catalysis by faujasite zeolites Rajamani Gounder a , Andrew and dehydrogenation and methanol dehydration turnover rates (per H+ ) among FAU zeolites treated thermally with steam dehydration catalysis; these titration values were also supported by commensurate changes in acidic OH

  6. One-step synthesis of mesoporous pentasil zeolite with single-unit-cell lamellar structural features

    SciTech Connect

    Tsapstsis, Michael; Zhang, Xueyi

    2015-11-17

    A method for making a pentasil zeolite material includes forming an aqueous solution that includes a structure directing agent and a silica precursor; and heating the solution at a sufficient temperature and for sufficient time to form a pentasil zeolite material from the silica precursor, wherein the structure directing agent includes a quaternary phosphonium ion.

  7. Synthesis, deposition and characterization of magnesium hydroxide nanostructures on zeolite 4A

    SciTech Connect

    Koh, Pei-Yoong; Yan, Jing; Ward, Jason; Koros, William J.; Teja, Amyn S.; Xu, Bo

    2011-03-15

    Research highlights: {yields} Reports a simple precipitation-growth method to produce nanostructures of Mg(OH){sub 2} on the surface of zeolite 4A. {yields} Able to control the growth of the nanostructures by manipulating the experimental procedure. {yields} Able to deposit Mg(OH){sub 2} onto specific sites namely bridging hydroxyl protons (SiOHAl) on the surface of zeolite 4A. -- Abstract: The precipitation and self-assembly of magnesium hydroxide Mg(OH){sub 2} nanopetals on dispersed zeolite 4A particles was investigated. Mg(OH){sub 2}/zeolite nanocomposites were produced from magnesium chloride solutions and characterized via X-ray powder diffraction (XRD), thermogravimetric analysis (TGA), scanning electron microscopy (SEM), Fourier transform infrared analysis (FTIR), and solid state NMR. It was determined that Mg(OH){sub 2} interacted with bridging hydroxyl protons (SiOHAl) on the zeolite surface, but not with silanol or aluminol groups. NMR analysis showed that 13% of the tetrahedral Al sites on the zeolite were converted to octahedral Al. The zeolite structure and crystallinity remained intact after treatment, and no dealumination reactions were detected. This suggests that the deposition-precipitation process at ambient conditions is a facile method for controlling Mg(OH){sub 2} nanostructures on zeolites.

  8. Can one and two-dimensional solid-state NMR fingerprint zeolite framework topology?

    PubMed

    Martineau, Charlotte; Vial, Sandrine; Barth, Dominique; Quessette, Franck; Taulelle, Francis

    2015-02-01

    In this contribution, we have explored the potential and strength of one-dimensional (1D) (29)Si and two-dimensional (2D) (29)S-(29)Si and (29)Si-(17)O NMR as invariants of non-oriented graph for fingerprinting zeolite frameworks. 1D and 2D (29)Si NMR can indeed provide indications on the graph vertices, edges and allow the construction of the adjacency matrix, i.e. the set of connections between the graph vertices. From the structural data, hypothetical 1D (29)Si and 2D (29)Si-(29)Si NMR signatures for 193 of the zeolite frameworks reported in the Atlas of Zeolite Structures have been generated. Comparison between all signatures shows that thanks to the 1D (29)Si NMR data only, almost 20% of the known zeolite frameworks could be distinguished. Further NMR signatures were generated by taking into account 2D (29)Si-(29)Si and (29)Si-(17)O correlations. By sorting and comparison of all the NMR data, up to 80% of the listed zeolites could be unambiguously discriminated. This work indicates that (i) solid-state NMR data indeed represent a rather strong graph invariant for zeolite framework, (ii) despite their difficulties and costs (isotopic labeling is often required, the NMR measurements can be long), (29)Si and (17)O NMR measurements are worth being investigated in the frame of zeolites structure resolution. This approach could also be generalized to other zeolite-related materials containing NMR-measurable nuclides. PMID:25454465

  9. Study of Molecular-Shape Selectivity of Zeolites by Gas Chromatography

    ERIC Educational Resources Information Center

    Chao, Pei-Yu; Chuang, Yao-Yuan; Ho, Grace Hsiuying; Chuang, Shiow-Huey; Tsai, Tseng-Chang; Lee, Chi-Young; Tsai, Shang-Tien; Huang, Jun-Fu

    2008-01-01

    A sorption experiment using a gas chromatograph is described that can help students understand the "molecular-shape selectivity" behavior of zeolites in the subnano regime. Hexane isomers are used as probe molecules to demonstrate the sorption phenomena. In the experiment, a zeolite adsorbs certain hexane isomers with molecular sizes smaller than…

  10. van der Waals density functional study of CO2 binding in zeolitic imidazolate frameworks

    E-print Network

    Ray, Keith G.; Olmsted, David; He, Ning; Houndonougbo, Yao; Laird, Brian Bostian; Asta, Mark

    2012-02-06

    The van der Waals density functional (vdW-DF) formalism is employed in a study of the binding energetics for CO2 in a set of five zeolitic imidazolate framework (ZIF) compounds. The ZIF structures investigated share the same RHO-type zeolite...

  11. Alkylation of dichlorobenzene isomers by olefins on zeolites Y and pentasil

    SciTech Connect

    Lishchiner, I.I.: Plakhotnik, V.A.; Kuz`micheva, A.N.

    1995-08-01

    Catalytic alkylation of dichlorobenzene isomers by ethylene and propylene on zeolite catalysts has been studied. It has been determined that using catalysts based on zeolite Y makes it possible to change the ratio of 1-alkyldichlorobenzenes formed within a wide range by varying the acidic properties of the catalysts.

  12. Tyrosine-Specific Chemical Modification with in Situ Hemin-Activated Luminol Derivatives.

    PubMed

    Sato, Shinichi; Nakamura, Kosuke; Nakamura, Hiroyuki

    2015-11-20

    Tyrosine-specific chemical modification was achieved using in situ hemin-activated luminol derivatives. Tyrosine residues in peptide and protein were modified effectively with N-methylated luminol derivatives under oxidative conditions in the presence of hemin and H2O2. Both single and double modifications of the tyrosine residue occurred in the reaction of angiotensin II with N-methylated luminol derivative 9. Tyrosine-specific chemical modification of the model protein bovine serum albumin (BSA) revealed that the surface-exposed tyrosine residues were selectively modified with 9. We succeeded in the functionalization of several proteins using azide-conjugated compound 18 using alkyne-conjugated probes by copper(I)-catalyzed azide-alkyne cycloaddition (CuAAC) or dibenzocyclooctyne (DBCO)-mediated copper-free click chemistry. This tyrosine-specific modification was orthogonal to conventional lysine modification by N-hydroxysuccinimide (NHS) ester, and dual functionalization by fluorescence modification of tyrosine residues and PEG modification of lysine residues was achieved without affecting the modification efficiency. PMID:26356088

  13. Removal of copper from ferrous scrap

    DOEpatents

    Blander, Milton (12833 S. 82nd Ct., Palos Park, IL 60464); Sinha, Shome N. (5748 Drexel, 2A, Chicago, IL 60637)

    1990-01-01

    A process for removing copper from ferrous or other metal scrap in which the scrap is contacted with a polyvalent metal sulfide slag in the presence of an excess of copper-sulfide forming additive to convert the copper to copper sulfide which is extracted into the slag to provide a ratio of copper in the slag to copper in the metal scrap of at least about 10.

  14. Removal of copper from ferrous scrap

    DOEpatents

    Blander, M.; Sinha, S.N.

    1990-05-15

    A process for removing copper from ferrous or other metal scrap in which the scrap is contacted with a polyvalent metal sulfide slag in the presence of an excess of copper-sulfide forming additive to convert the copper to copper sulfide which is extracted into the slag to provide a ratio of copper in the slag to copper in the metal scrap of at least about 10.

  15. Removal of copper from ferrous scrap

    DOEpatents

    Blander, M.; Sinha, S.N.

    1987-07-30

    A process for removing copper from ferrous or other metal scrap in which the scrap is contacted with a polyvalent metal sulfide slag in the presence of an excess of copper-sulfide forming additive to convert the copper to copper sulfide which is extracted into the slag to provide a ratio of copper in the slag to copper in the metal scrap of at least about 10.

  16. Discovery of optimal zeolites for challenging separations and chemical transformations using predictive materials modeling

    NASA Astrophysics Data System (ADS)

    Bai, Peng; Jeon, Mi Young; Ren, Limin; Knight, Chris; Deem, Michael W.; Tsapatsis, Michael; Siepmann, J. Ilja

    2015-01-01

    Zeolites play numerous important roles in modern petroleum refineries and have the potential to advance the production of fuels and chemical feedstocks from renewable resources. The performance of a zeolite as separation medium and catalyst depends on its framework structure. To date, 213 framework types have been synthesized and >330,000 thermodynamically accessible zeolite structures have been predicted. Hence, identification of optimal zeolites for a given application from the large pool of candidate structures is attractive for accelerating the pace of materials discovery. Here we identify, through a large-scale, multi-step computational screening process, promising zeolite structures for two energy-related applications: the purification of ethanol from fermentation broths and the hydroisomerization of alkanes with 18-30 carbon atoms encountered in petroleum refining. These results demonstrate that predictive modelling and data-driven science can now be applied to solve some of the most challenging separation problems involving highly non-ideal mixtures and highly articulated compounds.

  17. The development of a zeolite system for upgrade of the Process Waste Treatment Plant

    SciTech Connect

    Robinson, S.M.; Kent, T.E.; Arnold, W.D.; Parrott, J.R. Jr.

    1993-10-01

    Studies have been undertaken to design an efficient zeolite ion exchange system for use at the ORNL Process Waste Treatment Plant to remove cesium and strontium to meet discharge limits. This report focuses on two areas: (1) design of column hardware and pretreatment steps needed to eliminate column plugging and channeling and (2) development of equilibrium models for the wastewater system. Results indicate that zeolite columns do not plug as quickly when the wastewater equalization is performed in the new Bethel Valley Storage Tanks instead of the former equalization basin where suspended solids concentration is high. A down-flow column with spent zeolite was used successfully as a prefilter to prevent plugging of the zeolite columns being used to remove strontium and cesium. Equilibrium studies indicate that a Langmuir isotherm models binary zeolite equilibrium data while the modified Dubinin-Polyani model predicts multicomponent data.

  18. Preparation and Cation Exchange Properties of Zeolitic Adsorbents Using Fused Coal Fly Ash and Seawater

    NASA Astrophysics Data System (ADS)

    Hirai, Takashi; Wajima, Takaaki; Yoshizuka, Kazuharu

    For the development of functional material using coal fly ash discharged from thermal power plants, we have prepared zeolitic adsorbents derived from alkaline fused coal fly ash in several aqueous saline media to obtain the optimized preparation condition. The NH4+ exchange capacity of the product prepared at 80°C for 12 hours in diluted seawater using the precursor fused at 500°C was 4.6 mmol?g which is equivalent that of product prepared in deionized water. Zeolite-X and zeolite-A were produced in all aqueous media, in addition hydroxysodalite was produced over 12 hours. It was suggested that zeolite-A transform into hydroxysodalite in the products. The zeolitic adsorbents having high ion exchange capacity could be prepared in twice diluted seawater at 6-12 hours in 80°C using a precursor fused at 500°C.

  19. Wide spread zeolitization of the Neogene - Quaternary volcanic tuff in Jordan

    NASA Astrophysics Data System (ADS)

    Khoury, Hani N.; Ibrahim, Khalil M.; Al Dwairi, Reyad A.; Torrente, Domingo G.

    2015-01-01

    Representative samples were collected from well exposed Neogene - Quarternary scoria cones of north east Jordan. The results of this study have led to the discovery of eleven new localities of zeolite associated with the volcanic tuff. The zeolitization process of the volcanic tuff in Jordan is widespread and of regional distribution. The identified zeolites are phillipsite and chabazite with subordinate associations of faujasite and analcime. The zeolitization process resulted from the transformation of sideromelane into palagonite by the reaction of the scoria with the circulating meteoric water. The variation in the Na/K, Na/Ca and Si/Al ratios of the circulating water was responsible for the variation in the mineralogy and chemistry of the zeolites and the associated authigenic minerals.

  20. Entrainment behavior of copper and copper matte in copper smelting operations

    NASA Astrophysics Data System (ADS)

    Ip, S. W.; Toguri, J. M.

    1992-06-01

    In copper smelting, the loss of copper to the slag due to entrainment is largely influenced by the flotation of copper metal and/or matte in the slag phase. To evaluate this behavior, the surface tension of copper as a function of temperature and oxygen pressure and the interfacial tension of the copper-iron matte-slag system as a function of matte grade were measured. From the surface and interfacial tension values, the spreading and flotation coefficients of the copper, matte, and slag system were calculated. Ternary interfacial energy diagrams were also con-structed using these data. It is shown that matte droplets containing higher than 32 mass pct Cu will not form a film on rising gas bubbles when they collide in the slag phase. However, matte droplets will attach to gas bubbles upon collision and thus can be floated over the entire range of matte composition. Spreading of copper on bubbles is not possible at oxygen pressures between 10-12 and 10-8 atm. Flotation of copper by gas bubble in slag is possible at oxygen pressure higher than 10-9 atm. However, it is feasible for rising matte droplets (attached to rising bubble) to trap and float copper irrespective of the matte grade.

  1. On the Estimation of Average Crystallite Size of Zeolites from the Scherrer Equation: A Critical Evaluation of its Application to Zeolites with One-Dimensional Pore Systems

    SciTech Connect

    Burton, A.; Ong, K; Rea, T; Chan, I

    2009-01-01

    This article presents an overview of the application of the Scherrer equation and Williamson-Hall analysis for the approximation of crystallite sizes of zeolites. Special emphasis is placed on the proper selection of hkl reflections for estimating a particular dimension of a specimen with anisotropic crystals. Crystal sizes of zeolites with one-dimensional pores (such as ZSM-12, ZSM-48, ferrierite, or Theta-1) are especially prone to misreporting or error from a direct application of the Scherrer equation. We have collected synchrotron powder diffraction data on a group of MTT-type zeolites of varying morphologies. For typical values of strain we have determined for these zeolites, we find that large crystal lengths can be underestimated by orders of magnitude when the effects of stress are not (or cannot be) included in the analysis.

  2. Steady Deflagration of PBX-9501 Within a Copper Cylinder

    SciTech Connect

    Pemberton, Steven J.; Herrera, Dennis H.; Herrera, Tommy J.; Arellano, Jesus C.; Sandoval, Thomas D.

    2012-06-26

    A copper cylinder cook-off experiment has been designed to cause steady deflagration in PBX-9501 explosive material. The design is documented and preliminary copper expansion results are presented for steady deflagration with a reaction speed of 1092 +/- 24 m/s. The expansion of reaction products from the detonation of an explosive is something that is well understood, and reasonably simulated using documented equations of state (EOS) for many explosives of interest. These EOS were historically measured using a 'standard' copper cylinder test design; this design comprised an annealed, oxygen-free high conductivity (OFHC) copper tube filled with explosive material and detonated from one end. Expansion of the copper wall was measured as a function of time using either a streak camera (for classic testing), or more recently using laser velocimetry techniques. Expansion data were then used to derive the EOS in various preferred forms - which are not discussed here for the sake of brevity. [Catanach, et. al., 1999] When an explosive deflagrates rather than detonating, simulation becomes more difficult. Reaction products are released on a slower time scale, and the reactions are much more affected by the geometry and local temperature within the reaction environment. It is assumed that the standard, documented EOS will no longer apply. In an effort to establish a first order approximation of deflagration product behavior, a cook-off test has been designed to cause steady deflagration in PBX-9501 explosive material, and to record the copper expansion profile as a function of time during this test. The purpose of the current paper is to document the initial test design and report some preliminary results. A proposal for modification of the design is also presented.

  3. Copper and zinc recycling from copper alloys` spent pickling solutions

    SciTech Connect

    Roman-Moguel, G.J.; Plascencia, G.; Perez, J.

    1995-12-31

    The precipitation of copper and zinc as cements from a copper alloys` spent pickling solution has been studied at laboratory and pilot scale, with the objective of designing an economic process to recover both metals and render a solution to be either recycled to the pickling process or treated in a standard fashion and produce a non-hazardous sludge. The sulfuric acid spent pickling solution already containing copper and zinc was used first to dissolve another solid residue originated in the copper alloys foundry to neutralize part of the acidity. The resulting enriched solution was treated separately with two reductants: sodium borohydride and iron powder varying pH and excess of reductant under constant agitation. Under the best conditions, precipitation of over 95 percent of zinc and copper was achieved together with the reduction of lead and cadmium contents respectively. A process for the combined residues treatment is proposed.

  4. Modifications of gravity.

    PubMed

    Skordis, Constantinos

    2011-12-28

    General relativity (GR) is a phenomenologically successful theory that rests on firm foundations, but has not been tested on cosmological scales. The deep mystery of dark energy (and possibly even the requirement of cold dark matter (CDM)) has increased the need for testing modifications to GR, as the inference of such otherwise undetected fluids depends crucially on the theory of gravity. Here, I discuss a general scheme for constructing consistent and covariant modifications to the Einstein equations. This framework is such that there is a clear connection between the modification and the underlying field content that produces it. I argue that this is mandatory for distinguishing modifications of gravity from conventional fluids. I give a non-trivial example, a simple metric-based modification of the fluctuation equations for which the background is exact ?CDM, but differs from it in the perturbations. I show how this can be generalized and solved in terms of two arbitrary functions. Finally, I discuss future prospects and directions of research. PMID:22084286

  5. Nanoporous Zeolite Thin Film-Based Fiber Intrinsic Fabry-Perot Interferometric Sensor for Detection of Dissolved Organics in Water

    PubMed Central

    Liu, Ning; Hui, Juan; Sun, Cunqiang; Dong, Junhang; Zhang, Luzheng; Xiao, Hai

    2006-01-01

    A fiber optic intrinsic Fabry-Perot interferometric (IFPI) chemical sensor was developed by fine-polishing a thin layer of polycrystalline nanoporous MFI zeolite synthesized on the cleaved endface of a single mode fiber. The sensor operated by monitoring the optical thickness changes of the zeolite thin film caused by the adsorption of organic molecules into the zeolite channels. The optical thickness of the zeolite thin film was measured by white light interferometry. Using methanol, 2-propanol, and toluene as the model chemicals, it was demonstrated that the zeolite IPFI sensor could detect dissolved organics in water with high sensitivity.

  6. MODIFICATIONS TO REDUCE DRAG OUT AT A PRINTED CIRCUIT BOARD MANUFACTURER

    EPA Science Inventory

    This MnTAP/EPA Waste Reduction Innovative Technology Evaluation project at Micom, Inc., demonstrated the waste reducing capability of two simple rinsing modifications on an etchant and an electroless copper process. he simple, tow (or no) cost, low technology changes that were ma...

  7. Analysis of the biological and chemical reactivity of zeolite-based aluminosilicate fibers and particulates.

    PubMed Central

    Fach, Estelle; Waldman, W James; Williams, Marshall; Long, John; Meister, Richard K; Dutta, Prabir K

    2002-01-01

    Environmental and/or occupational exposure to minerals, metals, and fibers can cause lung diseases that may develop years after exposure to the agents. The presence of toxic fibers such as asbestos in the environment plus the continuing development of new mineral or vitreous fibers requires a better understanding of the specific physical and chemical features of fibers/particles responsible for bioactivity. Toward that goal, we have tested aluminosilicate zeolites to establish biological and chemical structure-function correlations. Zeolites have known crystal structure, are subject to experimental manipulation, and can be synthesized and controlled to produce particles of selected size and shape. Naturally occurring zeolites include forms whose biological activity is reported to range from highly pathogenic (erionite) to essentially benign (mordenite). Thus, we used naturally occurring erionite and mordenite as well as an extensively studied synthetic zeolite based on faujasite (zeolite Y). Bioactivity was evaluated using lung macrophages of rat origin (cell line NR8383). Our objective was to quantitatively determine the biological response upon interaction of the test particulates/fibers with lung macrophages and to evaluate the efficacy of surface iron on the zeolites to promote the Fenton reaction. The biological assessment included measurement of the reactive oxygen species by flow cytometry and chemiluminescence techniques upon phagocytosis of the minerals. The chemical assessment included measuring the hydroxyl radicals generated from hydrogen peroxide by iron bound to the zeolite particles and fibers (Fenton reaction). Chromatography as well as absorption spectroscopy were used to quantitate the hydroxyl radicals. We found that upon exposure to the same mass of a specific type of particulate, the oxidative burst increased with decreasing particle size, but remained relatively independent of zeolite composition. On the other hand, the Fenton reaction depended on the type of zeolite, suggesting that the surface structure of the zeolite plays an important role. PMID:12417479

  8. Recommended nomenclature for zeolite minerals: report of the subcommittee on zeolites of the International Mineralogical Association, Commission of New Minerals and Mineral Names

    USGS Publications Warehouse

    Coombs, D.S.; Alberti, A.; Armbruster, T.; Artioli, G.; Colella, C.; Galli, E.; Grice, Joel D.; Liebau, F.; Mandarino, J.A.; Minato, H.; Nickel, E.H.; Passaglia, E.; Peacor, D.R.; Quartieri, S.; Rinaldi, R.; Ross, M.; Sheppard, R.A.; Tillmanns, E.; Vezzalini, G.

    1998-01-01

    This report embodies recommendations on zeolite nomenclature approved by the International Mineralogical Association Commission of New Minerals and Mineral Names. In a working definition of a zeolite mineral used for review, interrupted tetrahedral framework structures are accepted where other zeolitic properties prevail, and complete substitution by elements other than Si and Al is allowed. Separate species are recognized in topologically distinctive compositional series in which different extra-framework cations are the most abundance in atomic proportions. To name these, the appropriate chemical symbol is attached by a hyphen to the series name as a suffix except for the names harmotome, pollucite and wairakite in the phillipsite and analcime series. Differences in space-group symmetry and in order-disorder relationships in zeolites having the same topologically distinctive framework do not in general provide adequate grounds for recognition of separate species. Zeolite species are not to be distinguished solely on Si:Al ratio except for heulandite (Si:Al < 4.0) and clinoptilolite (Si:Al ??? 4.0). Dehydration, partial hydration, and over-hydration are not sufficient grounds for the recognition of separate species of zeolites. Use of the term 'ideal formula' should be avoided in referring to a simplified or averaged formula of a zeolite. Newly recognized species in compositional series are as follows: brewsterite-Sr.-Ba: chabazite-Ca.-Na.-K; clinoptilolite-K, -Na, -Ca: dachiardite-Ca, -Na; erionite-K, -Ca: faujasite-Na, -Ca, -Na: paulingite-K. -Ca; phillipsite-Na, -Ca, -Ka; stilbite-Ca, -Na. Key references, type locality, origin of name, chemical data. IZA structure-type symbols, space-group symmetry; unit-cell dimensions, and comments on structure are listed for 13 compositional series, 82 accepted zeolite mineral species, and three of doubtful status. Herschelite, leonhardite, svetlozarite, and wellsite are discredited as mineral species names. Obsolete and discredited names are listed.

  9. Adsorption of aqueous copper on peanut hulls

    NASA Astrophysics Data System (ADS)

    Davis, Kanika Octavia

    A method was established for measuring the adsorption of Cu(II) from aqueous solution to unmodified and modified peanut hulls at constant temperature and pH. Modification of the hulls was performed by oxidation with alkaline hydrogen peroxide. During the modification process, the hydrogen peroxide solubilizes the lignin component, making the surface more porous which increases the availability of binding sites, while simultaneously oxidizing the cellulose. The oxidation of alcohol groups creates more binding sites by creating functional groups such as COO-, which increases chelation to metal ions. Fourier transform infrared spectroscopy confirms delignification of the peanut hulls by the disappearance of carboxyl peaks of the modified hulls, which were originally produced from the lignin content. Although, oxidation is not fully confirmed, it is not ruled out because the expected carboxylate peak (1680 cm-1) maybe overshadowed by a broad peak due to OH bending of water adsorbed to the hulls. Hulls adsorbed copper from solutions in the concentration range of 50-1000 ppm of CuCl2. Concentrations of pre- and post-adsorption solutions were determined using inductively coupled plasma optical emission spectroscopy. The adsorption isotherms were fit to known two and three-parameter models, evaluated and the binding mechanism was inferred. Maximum surface coverage was 3.5 +/- 0.6 mg Cu2+ /g hull for unmodified hulls and 11 +/- 1 mg Cu2+/g hull for modified hulls. The adsorption for the hulls is best described by the Langmuir model, suggesting monolayer, homogeneous adsorption. With a free energy of adsorption of 10.5 +/- 0.9 kJ/mol for unmodified hulls and 14.5 +/-0.4 kJ/mol for modified hulls, the process is categorized as chemisorption for both types of hulls. The adsorption for both hulls is also described by the Redlich-Peterson model, giving beta nearer to 1 than 0, which further suggests homogeneous adsorption described by the Langmuir model. After rinsing the hulls, scanning electron microscopy images coupled with energy dispersive X-ray spectroscopy showed that the percentage of copper on the modified hulls (2.5 %) was greater than on the unmodified hulls (1.6 %). This study concluded that the adsorption of copper using peanut hulls is a potential method for wastewater treatment and delignification and oxidation of the hulls increases the adsorption capacity approximately three-fold.

  10. Lead and Copper Control 101

    EPA Science Inventory

    This presentation is an overview of the most important water treatment strategies for the control of lead and copper release from drinking water corrosion. In addition to the sections specifically on lead and copper treatment, sections are included that cover sampling to find le...

  11. Copper deficiency mimicking myelodysplastic syndrome

    PubMed Central

    Dalal, Neil; Hooberman, Arthur; Mariani, Rachel; Sirota, Ronald; Lestingi, Timothy

    2015-01-01

    Key Clinical Message Copper deficiency is a rare cause of pancytopenia that may be mistaken for myelodysplastic syndrome. Cytoplasmic vacuolization in erythroid and myeloid precursors is found on bone marrow examination. Patients with a history of abdominal surgery who present with anemia and neutropenia with dysplastic changes should have copper levels checked. PMID:25984314

  12. Large-scale production of carbon-coated copper nanoparticles for sensor applications

    NASA Astrophysics Data System (ADS)

    Athanassiou, E. K.; Grass, R. N.; Stark, W. J.

    2006-03-01

    Copper nanoparticles with a mean carbon coating of about 1 nm were continuously produced at up to 10 g h-1 using a modified flame spray synthesis unit under highly reducing conditions. Raman spectroscopy and solid state 13C magic angle spinning nuclear magnetic resonance spectroscopy revealed that the thin carbon layer consisted of a sp2-hybridized carbon modification in the form of graphene stacks. The carbon layer protected the copper nanoparticles from oxidation in air. Bulk pills of pressed carbon/copper nanoparticles displayed a highly pressure- and temperature-dependent electrical conductivity with sensitivity at least comparable to commercial materials. These properties suggest the use of thin carbon/copper nanocomposites as novel, low-cost sensor materials and offer a metal-based alternative to the currently used brittle oxidic spinels or perovskites.

  13. Characteristic Significance of Magnetic Relaxations on Copper Oxide Thin Film Using the Bloch NMR

    NASA Astrophysics Data System (ADS)

    Emetere, Moses E.

    2014-08-01

    In this paper, a theoretical model was described to analyze the magnetic relaxations of samples of copper oxide thin film cells. Experimentally, the copper oxide thin film was characterized at different oxidation temperatures between 150°C to 450°C. The introduction of the Bloch NMR equations was developed to determine the functionality of the individual samples. The magnetic relaxation characterization confirmed the degree of disordered in the copper oxide sample. This disorderliness of the copper oxide sample engendered a magnetic instability which gave rise to magnetic deflagration. Magnetic deflagration was found to be dependent on the magnetic re-orientation initiated by the RF pulse. A new law was proposed which is a modification of the Arrhenius law.

  14. Production of copper and brass nanoparticles upon laser ablation in liquids

    SciTech Connect

    Kazakevich, Pavel V; Simakin, Aleksandr V; Shafeev, Georgii A; Voronov, Valerii V

    2004-10-31

    The production of nanoparticles upon ablation of copper and brass by pulsed radiation from Nd:YAG and copper lasers in water, ethanol, and acetone is studied. The nanoparticles were investigated by the methods of X-ray diffractometry, optical spectroscopy, and transmission electron microscopy. The produced copper and brass nanoparticles were shown to exhibit a plasmon resonance lying in the visible spectral range near 580 and 510 nm. The brass nanoparticles produced by ablation in ethanol have a shell approximately 10-nm thick for an average dimension of 20-30 nm. A chemical modification of ethanol was observed, which manifested itself in the appearance of intense UV absorption bands. Upon laser irradiation of brass nanoparticles in a liquid their absorption spectrum gradually transformed into the spectrum of copper nanoparticles. (interaction of laser radiation with matter)

  15. Gold Nanoclusters Entrapped in the Alpha-Cages of Y-Zeolites: Structural Characterization By X-Ray Absorption Spectroscopy

    SciTech Connect

    Fierro-Gonzalez, J.C.; Hao, Y.; Gates, B.C.

    2009-06-03

    Au(CH{sub 3}){sub 2}(C{sub 5}H{sub 7}O{sub 2}) was used as a precursor to synthesize mononuclear gold complexes in faujasites, NaY zeolite, and dealuminated Y zeolite. Treatment of these supported complexes in flowing helium as the temperature was increased led to the gradual reduction of the gold and formation of gold nanoclusters in each zeolite, which were characterized by X-ray absorption spectroscopy. After treatment at the highest temperature, 573 K, the average diameters of the gold clusters were approximately 10 and 8 {angstrom} in NaY zeolite and dealuminated Y zeolite, respectively; these clusters are smaller than the diameters of the {alpha}-cages of the zeolite. The results indicate that the supported clusters were trapped within these cages and that the cages limited their sizes; in contrast, clusters formed similarly on the surfaces of metal oxides are significantly larger than those formed in the zeolites.

  16. Impact of zeolite aging in hot liquid water on activity for acid-catalyzed dehydration of alcohols

    SciTech Connect

    Vjunov, Aleksei; Derewinski, Miroslaw A.; Fulton, John L.; Camaioni, Donald M.; Lercher, Johannes A.

    2015-08-19

    The catalytic performance of zeolite in aqueous medium depends on a multitude of factors, such as the concentration and distribution of active sites and framework integrity. Al K–edge extended X–ray absorption fine structure and 27Al MAS NMR spectroscopies in combination with DFT calculations are used to determine the distribution of tetrahedral Al sites both qualitatively and quantitatively for both parent and 48 h 160 ºC water treated HBEA catalysts. There is no evidence of Al coordination modification after aging in water. The distribution and concentration of Al T–sites, active centers for the dehydration of cyclohexanol, do not markedly impact the catalytic performance in water, because the Brønsted acidic protons are present in the form of hydrated hydronium ions and thus have very similar acid properties. The results suggest that all Brønsted acid sites are equally active in aqueous medium. The decrease of zeolite catalytic performance after water treatment is attributed to the reduced concentration of Brønsted acid sites. Increasing the stability of pore walls and decreasing the rate of Si–O–Si group hydrolysis may result in improved apparent zeolite catalytic performance in aqueous medium. Authors thank B. W. Arey (PNNL) for HIM measurements, T. Huthwelker for support during Al XAFS measurements at the Swiss Light Source (PSI, Switzerland), J. Z. Hu and S. D. Burton (PNNL) for support during NMR experiments. This work was supported by the U. S. Department of Energy (DOE), Office of Science, Office of Basic Energy Sciences, Division of Chemical Sciences, Geosciences & Biosciences. MD acknowledges support by the Materials Synthesis and Simulation Across Scales (MS3 Initiative) conducted under Laboratory Directed Research & Development Program at PNNL. HIM imaging and NMR experiments were performed at the Environmental Molecular Sciences Laboratory, a national scientific user facility sponsored by the DOE Office of Science, Office of Biological and Environmental Research, located at Pacific Northwest National Laboratory (PNNL). PNNL is a multiprogram national laboratory operated for the DOE by Battelle Memorial Institute under contract # DE-AC05-76RL0-1830

  17. Enhanced nonlinear optical characteristics of copper-ion-doped double crossover DNAs

    NASA Astrophysics Data System (ADS)

    Park, Byeongho; Lee, Byung Jic; Dugasani, Sreekantha Reddy; Cho, Youngho; Kim, Chulki; Seo, Minah; Lee, Taikjin; Jhon, Young Min; Choi, Jaebin; Lee, Seok; Park, Sung Ha; Jun, Seong Chan; Yeom, Dong-Il; Rotermund, Fabian; Kim, Jae Hun

    2015-10-01

    The modification of deoxyribonucleic acid (DNA) samples by sequencing the order of bases and doping copper ions opens the possibility for the design of novel nanomaterials exhibiting large optical nonlinearity. We investigated the nonlinear characteristics of copper-ion doped double crossover DNA samples for the first time to the best of our knowledge by using Z-scan and four-wave mixing methods. To accelerate the nonlinear characteristics, we prepared two types of unique DNA nanostructures composed of 148 base pairs doped with copper ions with a facile annealing method. The outstanding third-order nonlinear optical susceptibility of the copper-ion-doped DNA solution, 1.19 × 10-12 esu, was estimated by the conventional Z-scan measurement, whereas the four-wave mixing experiment was also investigated. In the visible spectral range, the copper-ion-doped DNA solution samples provided competent four-wave mixing signals with a remarkable conversion efficiency of -4.15 dB for the converted signal at 627 nm. The interactions between DNA and copper ions contribute to the enhancement of nonlinearity due to structural and functional changes. The present study signifies that the copper-ion-doped double crossover DNA is a potential candidate as a highly efficient novel material for further nonlinear optical applications.

  18. Modifications on Translation Initiation.

    PubMed

    Mitchell, Sarah F; Parker, Roy

    2015-11-01

    Two studies by Meyer et al. and Wang et al. demonstrate a role for m(6)A modification of mRNA in stimulating translation initiation. These findings add to the growing number of diverse mechanisms for translation initiation in eukaryotes. PMID:26544933

  19. Toy Modification Note. Revised.

    ERIC Educational Resources Information Center

    Vanderheiden, Gregg C.; And Others

    Described are toy modifications which enable handicapped individuals to operate battery-powered toys. A battery interrupter is explained as a device which fits between the batteries in a toy and provides the ability to have a separate on-off switch which can be custom designed to fit a handicapped user's needs. Construction and use of three types…

  20. Disruption of Chemically Killed Bacterial Cells by a Synthetic Zeolite

    PubMed Central

    Wistreich, George A.; Lechtman, Max D.; Baker, Richard F.; Bartholomew, J. W.

    1972-01-01

    The applicability of a synthetic zeolite (type 4A, Union Carbide Corp., Linde Div., New York, N.Y.) as a disruptive agent in a procedure for the preparation of pure bacterial cell wall fractions from a variety of phenol-killed gram-negative, gram-positive, and acid-fast bacteria was demonstrated. The disruptive effect was found to be limited with formaldehyde-killed gram-positive cells and most gram-positive cocci killed either by phenol or formaldehyde. Images PMID:4110424

  1. Decomposition of trichloroethene on ozone-adsorbed high silica zeolites.

    PubMed

    Fujita, Hirotaka; Izumi, Jun; Sagehashi, Masaki; Fujii, Takao; Sakoda, Akiyoshi

    2004-01-01

    We developed a novel ozonation process for water treatment using high silica zeolites as an adsorptive concentrator of water-dissolved ozone and organic pollutants, resulting in a significant increase in reaction rate. In experiments involving trichloroethene (TCE) decomposition using a tubular flow reactor, TCE decomposition was much greater in the presence of ZSM-5 (SiO(2)/Al(2)O(3) ratio=3000) than in its absence, possibly due to the high concentrations of ozone and TCE inside the adsorbent. The TCE conversion obtained in our experiments was found to reach its theoretically maximum limit. PMID:14630114

  2. Multiple episodes of zeolite deposition in fractured silicic tuff

    SciTech Connect

    Carlos, B.A.; Chipera, S.J.; Snow, M.G.

    1995-04-01

    Fractures in silicic tuffs above the water table at Yucca Mountain, Nevada, USA contain two morphologies of heulandite with different compositions. Tabular heulandite is zoned, with Sr-rich cores and Mg-rich rims. Later prismatic heulandite is nearly the same composition as the more magnesian rims. Heulandite and stellerite may occur between layers of calcite, and calcite occurs locally between generations of heulandite. Thermodynamic modeling, using estimated thermodynamic data and observed chemical compositions for heulandite and stellerite, shows that stellerite is the favored zeolite unless Ca concentrations are reduced or Mg and/or Sr concentrations are significantly elevated above current Yucca Mountain waters.

  3. Catalytic degradation of high density polyethylene using zeolites.

    PubMed

    Zaggout, F R; al Mughari, A R; Garforth, A

    2001-01-01

    Plastic wastes, which cause a serious environmental problem in urban areas, can serve as sources of energy. Catalytic treatment of High Density Polyethylene (HDPE) has shown that the degradation of HDPE resulted in the production of a stream of gaseous hydrocarbons varied in the range C1-C8. The degradation was carried out using diluted forms of zeolites ZSM-5, USY and Mordenite (MORD) using a fluidized bed reactor (FBR). Effect of coke formation on the activity of the catalysts was screened by thermogravimetric (TGA). ZSM-5 showed a significant resistance to deactivation because of the nature of its small pore size compared with USY and MORD. PMID:11382018

  4. Fabrication and material characterization of copper and copper-CNT micropillars

    NASA Astrophysics Data System (ADS)

    Ghanbari, S.; Darabi, J.

    2015-07-01

    In this work, copper micropillars and copper-carbon nanotube (CNT) composite micropillars were fabricated by incorporating an electrodeposition technique with a xurography process. In order to disperse carbon nanotubes in copper-CNT micropillars, various amounts of CNTs were added to the electroplating bath. Surface morphology and phase characterization of copper micropillars and copper-CNT composite micropillars were analyzed by optical microscopy and x-ray diffraction. In addition, the corrosion resistance (Rp) of a bare copper substrate, copper micropillars, and optimum copper-CNT micropillars were studied by electrochemical impedance spectroscopy (EIS) technique in a 3.5 wt.% sodium chloride. Experimental results yielded a corrosion resistance of 200 ? cm2 for the bare copper substrate, 400 ? cm2 for copper micropillars, and 2550 ? cm2 for copper-CNT micropillars, indicating a significantly higher corrosion resistance for copper-CNT micropillars due to a lower chemical reactivity and refinement of crystal structure of copper in micropillars.

  5. Improving Ammonium and Nitrate Release from Urea Using Clinoptilolite Zeolite and Compost Produced from Agricultural Wastes

    PubMed Central

    Omar, Latifah; Ahmed, Osumanu Haruna; Majid, Nik Muhamad Ab.

    2015-01-01

    Improper use of urea may cause environmental pollution through NH3 volatilization and NO3? leaching from urea. Clinoptilolite zeolite and compost could be used to control N loss from urea by controlling NH4+ and NO3? release from urea. Soil incubation and leaching experiments were conducted to determine the effects of clinoptilolite zeolite and compost on controlling NH4+ and NO3? losses from urea. Bekenu Series soil (Typic Paleudults) was incubated for 30, 60, and 90 days. A soil leaching experiment was conducted for 30 days. Urea amended with clinoptilolite zeolite and compost significantly reduced NH4+ and NO3? release from urea (soil incubation study) compared with urea alone, thus reducing leaching of these ions. Ammonium and NO3? leaching losses during the 30 days of the leaching experiment were highest in urea alone compared with urea with clinoptilolite zeolite and compost treatments. At 30 days of the leaching experiment, NH4+ retention in soil with urea amended with clinoptilolite zeolite and compost was better than that with urea alone. These observations were because of the high pH, CEC, and other chemical properties of clinoptilolite zeolite and compost. Urea can be amended with clinoptilolite zeolite and compost to improve NH4+ and NO3? release from urea. PMID:25793220

  6. Densification of salt-occluded zeolite a powders to a leach-resistant monolith

    SciTech Connect

    Lewis, M.A.; Fischer, D.F.; Murhpy, C.D.

    1993-10-01

    Pyrochemical processing of spent fuel from the Integral Fast Reactor (IFR) yields a salt waste of LiCl-KCl that contains approximately 6 wt% fission products, primarily as CsCl and SrCl{sub 2}. Past work has shown that zeolite A will preferentially sorb cesium and strontium and will encapsulate the salt waste in a leach-resistant, radiation-resistant aluminosilicate matrix. However, a method is sill needed to convert the salt-occluded zeolite powders into a form suitable for geologic disposal. We are thus investigating a method that forms bonded zeolite by hot pressing a mixture of glass frit and salt-occluded zeolite powders at 990 K (717{degree}C) and 28 MPa. The leach resistance of the bonded zeolite was measured in static leach tests run for 28 days in 363 K (90{degree}C) deionized water. Normalized release rates of all elements in the bonded zeolite were low, <1 g/m{sup 2} d. Thus, the bonded zeolite may be a suitable waste form for IFR salt waste.

  7. Fabrication of Poly(p-Phenylene)/Zeolite Composites and Their Responses Towards Ammonia

    PubMed Central

    Phumman, Pimchanok; Niamlang, Sumonman; Sirivat, Anuvat

    2009-01-01

    Poly(p-phenylene) (PPP) was chemically synthesized via oxidative polymerization using benzene and doped with FeCl3. The electrical conductivity response of the doped PPP (dPPP) towards CO, H2 and NH3 is investigated. dPPP shows no electrical conductivity response towards the first two gases (CO and H2), but it shows a definite negative response towards NH3. The electrical conductivity sensitivity of dPPP increases linearly with increasing NH3 concentration. To improve the sensitivity of the sensor towards NH3, ZSM-5 zeolite is added into the conductive polymer matrix. The electrical sensitivity of the sensor increases with increasing zeolite content up to 30%. The effect of the type of cation in the zeolite pores is investigated: namely, Na+, K+, NH4+ and H+. The electrical conductivity sensitivity of the composites with different cations in the zeolite can be arranged in this order: K+ < no zeolite < Na+ < NH4+ < H+. The variation in electrical sensitivity with cation type can be described in terms of the acid-base interaction, the zeolite pore size and surface area. The PPP/Zeolite composite with H+ possesses the highest electrical sensitivity of ?0.36 since H+ has the highest acidity, the highest pore volume and surface area, which combine to induce a more favorable NH3 adsorption and interaction with the conductive polymer. PMID:22408492

  8. Influence of different natural zeolite concentrations on the anaerobic digestion of piggery waste.

    PubMed

    Milán, Z; Sánchez, E; Weiland, P; Borja, R; Martín, A; Ilangovan, K

    2001-10-01

    The effect of different natural zeolite concentrations on the anaerobic digestion of piggery waste was studied. Natural zeolite doses in the range 0.2-10 g/l of wastewater were used in batch experiments, which were carried out at temperatures between 27 degrees C and 30 degrees C. Total chemical oxygen demand (COD), total and volatile solids, ammonia and organic nitrogen, pH, total volatile fatty acids (TVFA), alkalinity (Alk) and accumulative methane production were determined during 30 days of digestion. The anaerobic digestion process was favored by the addition of natural zeolite at doses between 2 and 4 g/l and increasingly inhibited at doses beyond 6 g/l. A first-order kinetic model of COD removal was used to determine the apparent kinetic constants of the process. The kinetic constant values increased with the zeolite amount up to a concentration of 4 g/l. The values of the maximum accumulative methane production (Gm) increased until zeolite concentrations of 2-4 g/l. The addition of zeolite reduced the values of the TVFA/ Alk ratio while increasing the pH values, and these facts could contribute to the process failure at zeolite doses of 10 g/l. PMID:11554599

  9. MFI-type zeolite functional liquid phase sensor coated on the optical fiber end-face

    NASA Astrophysics Data System (ADS)

    Hu, Yaoxin; Sidiroglou, Fotios; Hill, Matthew R.; Collins, Stephen F.; Duke, Mikel

    2012-02-01

    Optical fibers are a unique medium to coat with functional sensor materials that change in refractive index upon adsorption/interaction with specific compounds. In this work, we demonstrate a simple technique to coat the end face of an optical fiber with the microporous MFI-type zeolite. The exposure of the zeolite films from air to water or to aqueous solutions of ethanol and isopropanol causes a distinct change in the film's refractive index. This change was then detected using a simple fiber optic refractive index sensor by monitoring the signal intensity reflected back from the coated fiber endface and as the zeolite is transferred between air, water and solutions containing ethanol and isopropanol. The zeolite coating was developed using the in-situ templated growth technique to grow the zeolite crystals on the cleaved endface of an optical fiber. Effective coating was achieved when the fiber was oriented horizontally in the hydrothermal reactor. The zeolite coated end face reflected less energy in water, at 0.0201 ?W, and exhibited almost no change (~2% increase) with increasing ethanol concentration, but exhibited a 135% increase in reflected energy, i.e. 0.048 ?W, in 100% ethanol. The zeolite therefore gave the sensor alcohol selectivity. Further work is exploring applicability for liquid phase chemical and water quality analysis.

  10. Retardation of chromate through packed columns of surfactant-modified zeolite.

    PubMed

    Li, Zhaohui; Hong, Hanlie

    2009-03-15

    In this study, zeolite aggregates with particle size < 0.4, 1.4-2.4, and 3.6-4.8 mm were modified by the cationic surfactant hexadecyltrimethylammonium (HDTMA) bromide to a surfactant loading level of 80, 130, and 250 mmol kg(-1), respectively. The modified and unmodified zeolites were subjected to column tests to study the chromate transport and retardation as affected by particle size. At an input concentration of 11-15 mg L(-1), unmodified zeolite did not retard chromate transport for all three particle size ranges. In contrast, the observed retardation factor for chromate, defined as the number of pore volumes passed when the output concentration equals to half of the input concentration, was 55, 50, and 500 for the columns packed with 3.6-4.8, 1.4-2.4, and < 0.4 mm modified zeolite, respectively. Prolonged tailing of chromate desorption from the modified zeolite was the most striking feature after the feeding solution was switched from chromate to water at full breakthrough. Monitoring of HDTMA and counterion bromide concentration in the effluent revealed that slow but persistent desorption of HDTMA and bromide occurred throughout the transport experiment, which resulted in stripping off of the upper layer of the surfactant bilayer formation on zeolite. The change of HDTMA surfactant surface configuration from bilayer to monolayer resulted in a loss of functionality to absorb and immobilize chromate on the modified zeolite surfaces. PMID:18656307

  11. Amphiphilic organosilane-directed synthesis of crystalline zeolite with tunable mesoporosity.

    PubMed

    Choi, Minkee; Cho, Hae Sung; Srivastava, Rajendra; Venkatesan, Chithravel; Choi, Dae-Heung; Ryoo, Ryong

    2006-09-01

    Zeolites are a family of crystalline aluminosilicate materials widely used as shape-selective catalysts, ion exchange materials, and adsorbents for organic compounds. In the present work, zeolites were synthesized by adding a rationally designed amphiphilic organosilane surfactant to conventional alkaline zeolite synthesis mixtures. The zeolite products were characterized by a complementary combination of X-ray diffraction (XRD), nitrogen sorption, scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The analyses show that the present method is suitable as a direct synthesis route to highly mesoporous zeolites. The mesopore diameters could be uniformly tailored, similar to ordered mesoporous silica with amorphous frameworks. The mesoporous zeolite exhibited a narrow, small-angle XRD peak, which is characteristic of the short-range correlation between mesopores, similar to disordered wormhole-like mesoporous materials. The XRD patterns and electron micrographs of the samples taken during crystallization clearly showed the evolution of the mesoporous structure concomitantly to the crystallization of zeolite frameworks. The synthesis of the crystalline aluminosilicate materials with tunable mesoporosity and strong acidity has potentially important technological implications for catalytic reactions of large molecules, whereas conventional mesoporous materials lack hydrothermal stability and acidity. PMID:16892049

  12. Improving ammonium and nitrate release from urea using clinoptilolite zeolite and compost produced from agricultural wastes.

    PubMed

    Omar, Latifah; Ahmed, Osumanu Haruna; Ab Majid, Nik Muhamad

    2015-01-01

    Improper use of urea may cause environmental pollution through NH3 volatilization and NO3 (-) leaching from urea. Clinoptilolite zeolite and compost could be used to control N loss from urea by controlling NH4 (+) and NO3 (-) release from urea. Soil incubation and leaching experiments were conducted to determine the effects of clinoptilolite zeolite and compost on controlling NH4 (+) and NO3 (-) losses from urea. Bekenu Series soil (Typic Paleudults) was incubated for 30, 60, and 90 days. A soil leaching experiment was conducted for 30 days. Urea amended with clinoptilolite zeolite and compost significantly reduced NH4 (+) and NO3 (-) release from urea (soil incubation study) compared with urea alone, thus reducing leaching of these ions. Ammonium and NO3 (-) leaching losses during the 30 days of the leaching experiment were highest in urea alone compared with urea with clinoptilolite zeolite and compost treatments. At 30 days of the leaching experiment, NH4 (+) retention in soil with urea amended with clinoptilolite zeolite and compost was better than that with urea alone. These observations were because of the high pH, CEC, and other chemical properties of clinoptilolite zeolite and compost. Urea can be amended with clinoptilolite zeolite and compost to improve NH4 (+) and NO3 (-) release from urea. PMID:25793220

  13. Adsorptive removal of trace oxytetracycline from water by acid-modified zeolite: influencing factors.

    PubMed

    An, Wenhao; Xiao, Hua; Yu, Man; Chen, Xiaoyang; Xu, Yuxin; Zhou, Wenmin

    2013-01-01

    Because of the wide use of antibiotics in the livestock industry, trace tetracycline antibiotics are frequently detected in swine wastewater and water bodies near pig farms. Based on natural zeolite, modified zeolite was synthesized by treatment with nitric acid. As one kind of typical tetracyclines, oxytetracycline (OTC) was chosen as the target adsorbate. Removal of trace OTC by modified zeolite and the effects of several main water matrices on OTC adsorption were studied in detail. OTC removal efficiency by acid-modified zeolite was about 90%, compared to less than 20% by natural zeolite. In general, in acidic conditions the removal efficiency of OTC by modified zeolite was about 90%, which was much higher than 20-35% in alkaline conditions. An increase in ionic strength from 0.01 to 1.0 M led to a decrease in adsorption efficiency from 90 to 27%. The presence of 10.0 mg L(-1) dissolved humic acid accelerated sorption of OTC on modified zeolite, while 100.0 mg L(-1) humic acid resulted in the opposite effect. An increase in temperature contributed to enhancing the adsorption efficiency. PMID:24334898

  14. Distribution and chemistry of fracture-lining zeolites at Yucca Mountain, Nevada

    SciTech Connect

    Carlos, B.; Chipera, S.; Bish, D.; Raymond, R.

    1993-09-01

    Yucca Mountain, a > 1.5-km thick sequence of tuffs and subordinate lavas in southwest Nevada, is being investigated as a potential high-level nuclear waste repository site. Fracture-lining minerals are possible sources of information on past transport within the tuffs, and they may act as natural barriers to radionuclide migration along the fractures. Cores from several drill holes were examined to determine the distribution and chemistry of zeolite minerals in fractures. Fracture-lining minerals in the Paintbrush Tuff are highly variable in distribution, both vertically and laterally across the mountain, with mordenite, heulandite, and stellerite widespread in fractures even though the tuff matrix is generally devitrified and not zeolitic. Where heulandite occurs as both tabular and prismatic crystals in the same fracture, the two morphologies have different compositions, suggesting multiple episodes of zeolite formation within the fractures. In contrast to the Paintbrush Tuff, fractures in the Calico Hills Formation and the Crater Flat Tuff generally contain abundant clinoptilolite and mordenite only where the matrix is zeolitic, although mordenite does occur as fracture linings in some devitrified intervals of the Crater Flat Tuff as well. The fracture-lining zeolites correlate with the degree of alteration of the zeolitic tuffs, with clinoptilolite plus mordenite in tuffs containing clinoptilolite, and analcime in fractures limited to tuff intervals containing analcime. These data suggest that fracture-lining zeolite formation may have been coincident with the original alteration of the tuffs.

  15. Independent Evolution of Heavy Metal-Associated Domains in Copper Chaperones and Copper-Transporting ATPases

    E-print Network

    Jordan, King

    proteins that bind intracellular copper (Cu) and deliver it to Cu-dependent enzymes such as cytochrome -- Copper poisoning -- Wilson disease -- Menkes disease -- Mercury-binding protein Introduction Copper (CuIndependent Evolution of Heavy Metal-Associated Domains in Copper Chaperones and Copper

  16. 21 CFR 184.1260 - Copper gluconate.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Copper gluconate. 184.1260 Section 184.1260 Food... Specific Substances Affirmed as GRAS § 184.1260 Copper gluconate. (a) Copper gluconate (cupric gluconate... practice. Copper gluconate may be used in infant formula in accordance with section 412(g) of the...

  17. 49 CFR 192.279 - Copper pipe.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 49 Transportation 3 2010-10-01 2010-10-01 false Copper pipe. 192.279 Section 192.279 Transportation Other Regulations Relating to Transportation (Continued) PIPELINE AND HAZARDOUS MATERIALS SAFETY... Copper pipe. Copper pipe may not be threaded except that copper pipe used for joining screw fittings...

  18. 49 CFR 192.279 - Copper pipe.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ...3 2011-10-01 2011-10-01 false Copper pipe. 192.279 Section 192.279 Transportation...Materials Other Than by Welding § 192.279 Copper pipe. Copper pipe may not be threaded except that copper pipe...

  19. 49 CFR 192.279 - Copper pipe.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ...3 2010-10-01 2010-10-01 false Copper pipe. 192.279 Section 192.279 Transportation...Materials Other Than by Welding § 192.279 Copper pipe. Copper pipe may not be threaded except that copper pipe...

  20. 49 CFR 192.279 - Copper pipe.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ...Transportation 3 2014-10-01 2014-10-01 false Copper pipe. 192.279 Section 192.279 Transportation...of Materials Other Than by Welding § 192.279 Copper pipe. Copper pipe may not be threaded except that copper...

  1. 49 CFR 192.279 - Copper pipe.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ...Transportation 3 2013-10-01 2013-10-01 false Copper pipe. 192.279 Section 192.279 Transportation...of Materials Other Than by Welding § 192.279 Copper pipe. Copper pipe may not be threaded except that copper...

  2. 49 CFR 192.279 - Copper pipe.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ...Transportation 3 2012-10-01 2012-10-01 false Copper pipe. 192.279 Section 192.279 Transportation...of Materials Other Than by Welding § 192.279 Copper pipe. Copper pipe may not be threaded except that copper...

  3. Chemical changes associated with zeolitization of the tuffaceous beds of Calico Hills at Yucca Mountain, Nevada

    SciTech Connect

    Broxton, D.E.

    1992-03-01

    The chemistry of the tuffaceous beds of Calico Hills was examined in samples collected over a 100{sup 2} km area south of the Timber Mountain-Oasis Valley caldera complex to determine regional geochemical patterns during zeolitization. Samples of 58 vitric and zeolitic tuffs were analyzed for 48 elements by a combination of x-ray fluorescence, atomic absorption spectrophotometry, and neutron activation analysis. Major and trace element concentrations for zeolitic tuffs vary significantly from those for vitric tuffs. Complex, geographically-controlled patterns of elemental enrichment and depletion in the zeolitic tuffs are found for Na, K, Ca, Mg, U, Rb, Sr, Ba and Cs. Vitric and zeolitic tuffs generally have the same SiO{sub 2} contents on an anhydrous basis, but minor net silica gain or loss has occurred in some samples. Zeolitic tuffs from the northern part of the study area, adjacent to the caldera complex, are notably K-rich and Na- and U-poor compared to zeolitic tuffs to the south. The compositions of the K-rich zeolitic tuffs are similar to those found in other areas of the western US where volcanic rocks are affected by potassium metasomatism. Alteration of vitric tuffs took place in an open chemical system and geographic control of major element compositions probably reflects regional variations in groundwater chemistry during alteration. The K-rich zeolitic tuffs in the northern part of the study area were probably altered by hydrothermal fluids whereas tuffs further south were altered by lower-temperature groundwaters.

  4. Zeolite Membrane Reactor for Water Gas Shift Reaction for Hydrogen Production

    SciTech Connect

    Lin, Jerry Y.S.

    2013-01-29

    Gasification of biomass or heavy feedstock to produce hydrogen fuel gas using current technology is costly and energy-intensive. The technology includes water gas shift reaction in two or more reactor stages with inter-cooling to maximize conversion for a given catalyst volume. This project is focused on developing a membrane reactor for efficient conversion of water gas shift reaction to produce a hydrogen stream as a fuel and a carbon dioxide stream suitable for sequestration. The project was focused on synthesizing stable, hydrogen perm-selective MFI zeolite membranes for high temperature hydrogen separation; fabricating tubular MFI zeolite membrane reactor and stable water gas shift catalyst for membrane reactor applications, and identifying experimental conditions for water gas shift reaction in the zeolite membrane reactor that will produce a high purity hydrogen stream. The project has improved understanding of zeolite membrane synthesis, high temperature gas diffusion and separation mechanisms for zeolite membranes, synthesis and properties of sulfur resistant catalysts, fabrication and structure optimization of membrane supports, and fundamentals of coupling reaction with separation in zeolite membrane reactor for water gas shift reaction. Through the fundamental study, the research teams have developed MFI zeolite membranes with good perm-selectivity for hydrogen over carbon dioxide, carbon monoxide and water vapor, and high stability for operation in syngas mixture containing 500 part per million hydrogen sulfide at high temperatures around 500°C. The research teams also developed a sulfur resistant catalyst for water gas shift reaction. Modeling and experimental studies on the zeolite membrane reactor for water gas shift reaction have demonstrated the effective use of the zeolite membrane reactor for production of high purity hydrogen stream.

  5. NID Copper Sample Analysis

    SciTech Connect

    Kouzes, Richard T.; Zhu, Zihua

    2011-09-12

    The current focal point of the nuclear physics program at PNNL is the MAJORANA DEMONSTRATOR, and the follow-on Tonne-Scale experiment, a large array of ultra-low background high-purity germanium detectors, enriched in 76Ge, designed to search for zero-neutrino double-beta decay (0???). This experiment requires the use of germanium isotopically enriched in 76Ge. The MAJORANA DEMONSTRATOR is a DOE and NSF funded project with a major science impact. The DEMONSTRATOR will utilize 76Ge from Russia, but for the Tonne-Scale experiment it is hoped that an alternate technology, possibly one under development at Nonlinear Ion Dynamics (NID), will be a viable, US-based, lower-cost source of separated material. Samples of separated material from NID require analysis to determine the isotopic distribution and impurities. DOE is funding NID through an SBIR grant for development of their separation technology for application to the Tonne-Scale experiment. The Environmental Molecular Sciences facility (EMSL), a DOE user facility at PNNL, has the required mass spectroscopy instruments for making isotopic measurements that are essential to the quality assurance for the MAJORANA DEMONSTRATOR and for the development of the future separation technology required for the Tonne-Scale experiment. A sample of isotopically separated copper was provided by NID to PNNL in January 2011 for isotopic analysis as a test of the NID technology. The results of that analysis are reported here. A second sample of isotopically separated copper was provided by NID to PNNL in August 2011 for isotopic analysis as a test of the NID technology. The results of that analysis are also reported here.

  6. Effect of synthetic conditions on the adsorption properties of the resulting offretite-type zeolite

    NASA Astrophysics Data System (ADS)

    Gorshunova, K. K.; Travkina, O. S.; Kapustin, G. I.; Kustov, L. M.; Pavlov, M. L.; Kutepov, B. I.

    2015-05-01

    The effect of the nature of the silicon-containing component of the reaction mixture and that of the crystallization conditions on characteristics of the resulting offretite-type zeolite powder, including its degree of crystallinity, particle-size distribution, and adsorption properties with respect to toluene, cyclohexane, n-hexane, and water molecules, are considered. The thermal desorption of toluene from cationic forms of the offretite-type zeolite is reported. The K-forms of this zeolite can retain adsorbed toluene up to 300-400°C.

  7. Conversion of biomass to ethanol: Isomerization of xylose over HY zeolite

    SciTech Connect

    Lee, C.Y.; Wen, J.; Thomas, S.

    1995-12-31

    Xylose, a pentose indigestible to most yeasts, was converted to ethanol by a two-step isomerization and fermentation. HY zeolite was used to catalyze the isomerization of xylose, and the xylulose produced was directly used as the carbon source in ethanol fermentation. Zeolite catalysts offer pH compatibility with yeast fermentation and the ability to carry out isomerization at higher temperature where equilibrium xylulose concentration is higher. Initial rate studies indicate that xylose consumption follows pseudo-first-order kinetics, with a specific rate constant of 6.2 x 10{sup -4} L/solution/g zeolite/h.

  8. Adsorption interaction in the molecular hydrogen-aluminophosphate AlPO-5 zeolite system

    NASA Astrophysics Data System (ADS)

    Grenev, I. V.; Gavrilov, V. Yu.

    2015-03-01

    The adsorption interaction between molecular hydrogen and atoms forming the lattice of AlPO-5 zeolite is studied. The potential of intramolecular interaction is calculated by summing the potentials of individual pairwise H2-O(Al, P) interactions in a fragment of the zeolite structure with a volume of ˜32 nm3. Isopotential surfaces are constructed that allow determination of the shape of zeolite microchannels and the places of the preferential localization of sorbate molecules in the porous space. The calculated and experimental values of the Henry constant of H2 adsorption on AlPO-5 at 77 K are compared.

  9. Predicting Large CO2 Adsorption in Aluminosilicate Zeolites for Postcombustion Carbon Dioxide Capture

    SciTech Connect

    Kim, J; Lin, LC; Swisher, JA; Haranczyk, M; Smit, B

    2012-11-21

    Large-scale simulations of aluminosilicate zeolites were conducted to identify structures that possess large CO2 uptake for postcombustion carbon dioxide capture. In this study, we discovered that the aluminosilicate zeolite structures with the highest CO2 uptake values have an idealized silica lattice with a large free volume and a framework topology that maximizes the regions with nearest-neighbor framework atom distances from 3 to 4.5 angstrom. These predictors extend well to different Si:Al ratios and for both Na+ and Ca2+ cations, demonstrating their universal applicability in identifying the best-performing aluminosilicate zeolite structures.

  10. Iridium Complexes and Clusters in Dealuminated Zeolite HY: Distribution between Crystalline and Impurity Amorphous Regions

    SciTech Connect

    Martinez-Macias, Claudia; Xu, Pinghong; Hwang, Son-Jong; Lu, Jing; Chen, Cong-Yan; Browning, Nigel D.; Gates, Bruce C.

    2014-07-08

    Dealuminated zeolite HY was used to support Ir(CO)2 complexes formed from Ir(CO)2(C5H7O2). Infrared and X-ray absorption spectra and atomic-resolution electron microscopy images identify these complexes, and the images and 27Al NMR spectra identify impurity amorphous regions in the zeolite where the iridium is more susceptible to aggregation than in the crystalline regions. The results indicate a significant stability limitation of metal in amorphous impurity regions of zeolites.

  11. Metal-to-insulator crossover in alkali doped zeolite.

    PubMed

    Igarashi, Mutsuo; Jegli?, Peter; Krajnc, Andraž; Žitko, Rok; Nakano, Takehito; Nozue, Yasuo; Ar?on, Denis

    2016-01-01

    We report a systematic nuclear magnetic resonance investigation of the (23)Na spin-lattice relaxation rate, 1/T1, in sodium loaded low-silica X (LSX) zeolite, Nan/Na12-LSX, for various loading levels of sodium atoms n across the metal-to-insulator crossover. For high loading levels of n???14.2, 1/T1T shows nearly temperature-independent behaviour between 10?K and 25?K consistent with the Korringa relaxation mechanism and the metallic ground state. As the loading levels decrease below n???11.6, the extracted density of states (DOS) at the Fermi level sharply decreases, although a residual DOS at Fermi level is still observed even in the samples that lack the metallic Drude-peak in the optical reflectance. The observed crossover is a result of a complex loading-level dependence of electric potential felt by the electrons confined to zeolite cages, where the electronic correlations and disorder both play an important role. PMID:26725368

  12. Conversion of Methanol, Ethanol and Propanol over Zeolites

    SciTech Connect

    Ramasamy, Karthikeyan K.; Wang, Yong

    2013-06-04

    Renewable fuel from lignocellulosic biomass has recently attracted more attention due to its environmental and the potential economic benefits over the crude oil [1]. In particular the production of fuel range hydrocarbon (HC) from alcohol generated lots of interest since the alcohol can be produced from biomass via thermochemical [2] (mixed alcohol from gasification derived synthesis gas) as well as the biochemical routes [3] (alcohol fermentation). Along with the development of ZSM5 synthesis and the discovery of methanol-to-gasoline (MTG) process by Mobil in 1970’s triggered lots of interest in research and development arena to understand the reaction mechanisms of alcohols over zeolites in particular ZSM5 [4]. More detailed research on methanol conversion was extensively reported [5] and in recent times the research work can be found on ethanol [6] and other alcohols as well but comprehensive comparison of catalyst activity and the deactivation mechanism of the conversion of various alcohols over zeolites has not been reported. The experiments were conducted on smaller alcohols such as methanol, ethanol and 1-propanol over HZSM5. The experimental results on the catalyst activity and the catalyst deactivation mechanism will be discussed.

  13. Zeolite parageneses in the North Atlantic igneous province: Implications for geotectonics and groundwater quality of basaltic crust

    SciTech Connect

    Neuhoff, P.S.; Fridriksson, T.; Bird, D.K.

    2000-01-01

    Zeolites are among the most common products of chemical interaction between groundwaters and the Earth's crust during diagenesis and low-grade metamorphism. The unique crystal structures of zeolites result in large molar volumes, high cation-exchange capacities, and reversible dehydration. These properties influence both the stability and chemistry of zeolites in geologic systems, leading to complex parageneses and compositional relationships that provide sensitive indicators of physicochemical conditions in the crust. Observations of zeolite occurrence in Tertiary basaltic lavas in the North Atlantic region indicate that individual zeolite minerals are distributed in distinct, depth-controlled zones that parallel the paleosurface of the plateau basalts and transgress the lava stratigraphy. The zeolite zones are interpreted to have formed at the end of burial metamorphism of the lavas. Relative timing relations between various mineral parageneses and crustal-scale deformal features indicate that the minerals indicative of the zeolite zones formed within 1 million years after cessation of volcanism. Empirical correlation between the depth distribution of zeolite zones and the temperatures of formation of zeolites in geothermal systems provides estimates of regional thermal gradients and heat flow in flood-basalt provinces. Similarly, the orientations of zeolite zones can be used to distinguish synvolcanic and post-volcanic crustal deformation. Because zeolites that characterize the individual zones display different ion-exchange selectivities for various cations, reactions between groundwaters and zeolites in basaltic aquifers can result in depth-controlled zones where individual elements are concentrated in the crust. This is established for Sr, which is concentrated by at least an order of magnitude in heulandite, resulting in an overall SR enrichment of lavas in the heulandite-stilbite zeolite zone.

  14. Majorana Electroformed Copper Mechanical Analysis

    SciTech Connect

    Overman, Nicole R.; Overman, Cory T.; Kafentzis, Tyler A.; Edwards, Danny J.; Hoppe, Eric W.

    2012-04-30

    The MAJORANA DEMONSTRATOR is a large array of ultra-low background high-purity germanium detectors, enriched in 76Ge, designed to search for zero-neutrino double-beta decay. The DEMONSTRATOR will utilize ultra high purity electroformed copper for a variety of detector components and shielding. A preliminary mechanical evaluation was performed on the Majorana prototype electroformed copper material. Several samples were removed from a variety of positions on the mandrel. Tensile testing, optical metallography, scanning electron microscopy, and hardness testing were conducted to evaluate mechanical response. Analyses carried out on the Majorana prototype copper to this point show consistent mechanical response from a variety of test locations. Evaluation shows the copper meets or exceeds the design specifications.

  15. Metal-organic and zeolite imidazolate frameworks (MOFs and ZIFs) for highly selective separations

    SciTech Connect

    Omar M. Yaghi

    2012-09-17

    Metal-organic and zeolite imidazolate frameworks (MOFs and ZIFs) have been investigated for the realization as separation media with high selectivity. These structures are held together with strong bonds, making them architecturally, chemically, and thermally stable. Therefore, employing well designed building units, it is possible to discover promising materials for gas and vapor separation. This grant was focused on the study of MOFs and ZIFs with these specific objectives: (i) to develop a strategy for producing MOFs and ZIFs that combine high surface areas with active sites for their use in gas adsorption and separation of small organic compounds, (ii) to introduce active sites in the framework by a post-synthetic modification and metalation of MOFs and ZIFs, and (iii) to design and synthesize MOFs with extremely high surface areas and large pore volumes to accommodate large amounts of guest molecules. By the systematic study, this effort demonstrated how to introduce active functional groups in the frameworks, and this is also the origin of a new strategy, which is termed isoreticular functionalization and metalation. However, a large pore volume is still a prerequisite feature. One of the solutions to overcome this challenge is an isoreticular expansion of a MOF�������¢����������������s structure. With triangular organic linker and square building units, we demonstrated that MOF-399 has a unit cell volume 17 times larger than that of the first reported material isoreticular to it, and it has the highest porosity (94%) and lowest density (0.126 g cm-3) of any MOF reported to date. MOFs are not just low density materials; the guest-free form of MOF-210 demonstrates an ultrahigh porosity, whose BET surface area was estimated to be 6240 m2 g-1 by N2 adsorption measurements.

  16. Carbon dioxide and methane transport in DDR zeolite: insights from molecular simulations into carbon dioxide separations in small pore zeolites

    NASA Astrophysics Data System (ADS)

    Jee, Sang Eun; Sholl, David

    2009-03-01

    Zeolites are good candidates as a membranes for chemical separations because of their excellent chemical and thermal stability. Cage type zeolites are promising materials for gas separation since their narrow windows are expected to control molecular transport. DDR is one of the strongest candidates for light gas separations because of its narrow 8MR window. In our study, we examined the separation selectivity of DDR for CO2/CH4 separation using atomistic simulation methods. We introduced new force fields which can reproduce experimental single component adsorption and diffusion data for this material for the first time. Previously interatomic potentials that have been applied to DDR overestimate experimental diffusivities at least one order of magnitude. We characterized single-component and binary adsorption using Grand Canonical Monte Carlo, and single-component. diffusion using a combination of Molecular Dynamics and Transition State Theory. The most important observation from our calculation is that CO2/CH4 diffusion in DDR is very different from the usual situation in nanoporous materials, where the presence of a slowly diffusing species retards transport rates of a more rapidly diffusing species. In DDR, we show that CO2 diffusion rates are only weakly affected by the presence of CH4, despite the very slow diffusion of the latter species. The physical origins of this unusual behavior are explained by analyzing the adsorption sites and diffusion mechanism for each species.

  17. Zeolite formation from coal fly ash and heavy metal ion removal characteristics of thus-obtained Zeolite X in multi-metal systems.

    PubMed

    Jha, Vinay Kumar; Nagae, Masahiro; Matsuda, Motohide; Miyake, Michihiro

    2009-06-01

    Zeolitic materials have been prepared from coal fly ash as well as from a SiO(2)-Al(2)O(3) system upon NaOH fusion treatment, followed by subsequent hydrothermal processing at various NaOH concentrations and reaction times. During the preparation process, the starting material initially decomposed to an amorphous form, and the nucleation process of the zeolite began. The carbon content of the starting material influenced the formation of the zeolite by providing an active surface for nucleation. Zeolite A (Na-A) was transformed into zeolite X (Na-X) with increasing NaOH concentration and reaction time. The adsorption isotherms of the obtained Na-X based on the characteristics required to remove heavy ions such as Ni(2+), Cu(2+), Cd(2+) and Pb(2+) were examined in multi-metal systems. Thus obtained experimental data suggests that the Langmuir and Freundlich models are more accurate compared to the Dubinin-Kaganer-Radushkevich (DKR) model. However, the sorption energy obtained from the DKR model was helpful in elucidating the mechanism of the sorption process. Further, in going from a single- to multi-metal system, the degree of fitting for the Freundlich model compared with the Langmuir model was favored due to its basic assumption of a heterogeneity factor. The Extended-Langmuir model may be used in multi-metal systems, but gives a lower value for equilibrium sorption compared with the Langmuir model. PMID:19233542

  18. Recent advances in copper radiopharmaceuticals.

    PubMed

    Hao, Guiyang; Singh, Ajay N; Oz, Orhan K; Sun, Xiankai

    2011-04-01

    Copper has five radioisotopes ((60)Cu, (61)Cu, (62)Cu, (64)Cu, and (67)Cu) that can be used in copper radiopharmaceuticals. These radioisotopes decay by mixed emissions of ?+, ?-, and ? with a wide range of half-lives from 9.74 min ((62)Cu) to 2.58 d ((67)Cu), which enable the design and synthesis of a variety of radiopharmaceuticals for different biomedical applications in diagnostic and therapeutic nuclear medicine. However, due to the availability and production cost, the research efforts in copper radiopharmaceuticals are mainly focused on the use of (64)Cu (t(1/2) = 12.7 h; 17.4% ?+, 43% EC, 39% ?-), a radioisotope with low positron energy (E ?+max = 0.656 MeV) that is ideal for positron emission tomography (PET) imaging quantification and ?- emissions along with Auger electron for radiotherapy. Driven by the ever-increasing availability of preclinical and clinical PET scanners, a considerable interest has been seen in the development of novel copper radiopharmaceuticals in the past decade for a variety of diseases as represented by PET imaging of cancer. To avoid unnecessary literature redundancy, this review focuses on the unrepresented research aspects of copper chemistry (e.g. electrochemistry) and their uses in the evaluation of novel nuclear imaging probe design and recent advances in the field towards the practical use of copper radiopharmaceuticals. PMID:22191650

  19. Formation of copper-indium-selenide and/or copper-indium-gallium-selenide films from indium selenide and copper selenide precursors

    SciTech Connect

    Curtis, Calvin J.; Miedaner, Alexander; Van Hest, Maikel; Ginley, David S.; Nekuda, Jennifer A.

    2011-11-15

    Liquid-based indium selenide and copper selenide precursors, including copper-organoselenides, particulate copper selenide suspensions, copper selenide ethylene diamine in liquid solvent, nanoparticulate indium selenide suspensions, and indium selenide ethylene diamine coordination compounds in solvent, are used to form crystalline copper-indium-selenide, and/or copper indium gallium selenide films (66) on substrates (52).

  20. Copper-Based Ultrathin Nickel Nanocone Films with High-Efficiency Dropwise Condensation Heat Transfer Performance.

    PubMed

    Zhao, Ye; Luo, Yuting; Zhu, Jie; Li, Juan; Gao, Xuefeng

    2015-06-10

    We report a type of copper-based ultrathin nickel nanocone films with high-efficiency dropwise condensation heat transfer (DCHT) performance, which can be fabricated by facile electrodeposition and low-surface-energy chemistry modification. Compared with flat copper samples, our nanosamples show condensate microdrop self-propelling (CMDSP) function and over 89% enhancement in the DCHT coefficient. Such remarkable enhancement may be ascribed to the cooperation of surface nanostructure-induced CMDSP function as well as in situ integration and ultrathin nature of nanofilms. These findings are very significant to design and develop advanced DCHT materials and devices, which help improve the efficiency of thermal management and energy utilization. PMID:26011021