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Sample records for zeolite-supported copper progress

  1. Identification and Quantification of Copper Sites in Zeolites by Electron Paramagnetic Resonance Spectroscopy

    DEFF Research Database (Denmark)

    Godiksen, Anita; Vennestrøm, Peter N. R.; Rasmussen, Søren Birk

    2017-01-01

    Recent quantitative electron paramagnetic resonance spectroscopy (EPR) data on different copper species present in copper exchanged CHA zeolites are presented and put into context with the literature on other copper zeolites. Results presented herein were obtained using ex situ and in situ EPR...

  2. Copper removal and nickel for exchange cationic with a natural zeolite

    International Nuclear Information System (INIS)

    Estupinan, Arnoldy; Sarmiento, Diego; Belalcazar de Galvis, Ana Maria

    1998-01-01

    Natural zeolite clinoptilolite, was used to remove copper and nickel from waste waters of a galvanotechnical company. Exchange capacity determined for the zeolite after its transformation to homoionic sodium form, was 0.794 meq/g for copper and 0.447 meq/g for nickel. There were made batch and column experiments, reaching the last one a better approach to the equilibrium. From the degeneration essays, the sodical zeolite concentrates the copper in the waste waters to 23.5 up times the level found for the acid rinsing waters; it shows its potential use in treatment of these waste, because its effectiveness and low cost

  3. Copper nanoparticles in zeolite Y

    NARCIS (Netherlands)

    Seidel, A.; Loos, J.; Boddenberg, B.

    1999-01-01

    CuCl has been dispersed in the supercages of a Y-type zeolite by heating a mechanical salt/host mixture in vacuo. The occluded salt was subsequently reduced to copper metal in a hydrogen atmosphere. Virtually complete reduction of the salt is achieved at 460°C. Under the same conditions,

  4. Copper removal using bio-inspired polydopamine coated natural zeolites

    Energy Technology Data Exchange (ETDEWEB)

    Yu, Yang; Shapter, Joseph G. [Flinders Centre for Nanoscale Science and Technology, School of Chemical and Physical Sciences, Flinders University, Sturt Road, Bedford Park, Adelaide 5042, SA (Australia); Popelka-Filcoff, Rachel [School of Chemical and Physical Sciences, Flinders University, Sturt Road, Bedford Park, Adelaide 5042, SA (Australia); Bennett, John W. [Centre for Nuclear Applications, Australian Nuclear Science and Technology Organisation, Lucas Heights 2234, NSW (Australia); Ellis, Amanda V., E-mail: Amanda.Ellis@flinders.edu.au [Flinders Centre for Nanoscale Science and Technology, School of Chemical and Physical Sciences, Flinders University, Sturt Road, Bedford Park, Adelaide 5042, SA (Australia)

    2014-05-01

    Highlights: • Natural zeolites were modified with bio-inspired polydopamine. • A 91.4% increase in Cu(II) ion adsorption capacity was observed. • Atomic absorption and neutron activation analysis gave corroborative results. • Neutron activation analysis was used to provide accurate information on 30+ elements. • Approximately 90% of the adsorbed copper could be recovered by 0.1 M HCl treatment. - Abstract: Herein, for the first time, natural clinoptilolite-rich zeolite powders modified with a bio-inspired adhesive, polydopamine (PDA), have been systematically studied as an adsorbent for copper cations (Cu(II)) from aqueous solution. Fourier transform infrared (FTIR) spectroscopy, X-ray photoelectron spectroscopy (XPS) and thermogravimetric analysis (TGA) revealed successful grafting of PDA onto the zeolite surface. The effects of pH (2–5.5), PDA treatment time (3–24 h), contact time (0 to 24 h) and initial Cu(II) ion concentrations (1 to 500 mg dm{sup −3}) on the adsorption of Cu(II) ions were studied using atomic absorption spectroscopy (AAS) and neutron activation analysis (NAA). The adsorption behavior was fitted to a Langmuir isotherm and shown to follow a pseudo-second-order reaction model. The maximum adsorption capacities of Cu(II) were shown to be 14.93 mg g{sup −1} for pristine natural zeolite and 28.58 mg g{sup −1} for PDA treated zeolite powders. This impressive 91.4% increase in Cu(II) ion adsorption capacity is attributed to the chelating ability of the PDA on the zeolite surface. Furthermore studies of recyclability using NAA showed that over 50% of the adsorbed copper could be removed in mild concentrations (0.01 M or 0.1 M) of either acid or base.

  5. Copper removal using bio-inspired polydopamine coated natural zeolites

    International Nuclear Information System (INIS)

    Yu, Yang; Shapter, Joseph G.; Popelka-Filcoff, Rachel; Bennett, John W.; Ellis, Amanda V.

    2014-01-01

    Highlights: • Natural zeolites were modified with bio-inspired polydopamine. • A 91.4% increase in Cu(II) ion adsorption capacity was observed. • Atomic absorption and neutron activation analysis gave corroborative results. • Neutron activation analysis was used to provide accurate information on 30+ elements. • Approximately 90% of the adsorbed copper could be recovered by 0.1 M HCl treatment. - Abstract: Herein, for the first time, natural clinoptilolite-rich zeolite powders modified with a bio-inspired adhesive, polydopamine (PDA), have been systematically studied as an adsorbent for copper cations (Cu(II)) from aqueous solution. Fourier transform infrared (FTIR) spectroscopy, X-ray photoelectron spectroscopy (XPS) and thermogravimetric analysis (TGA) revealed successful grafting of PDA onto the zeolite surface. The effects of pH (2–5.5), PDA treatment time (3–24 h), contact time (0 to 24 h) and initial Cu(II) ion concentrations (1 to 500 mg dm −3 ) on the adsorption of Cu(II) ions were studied using atomic absorption spectroscopy (AAS) and neutron activation analysis (NAA). The adsorption behavior was fitted to a Langmuir isotherm and shown to follow a pseudo-second-order reaction model. The maximum adsorption capacities of Cu(II) were shown to be 14.93 mg g −1 for pristine natural zeolite and 28.58 mg g −1 for PDA treated zeolite powders. This impressive 91.4% increase in Cu(II) ion adsorption capacity is attributed to the chelating ability of the PDA on the zeolite surface. Furthermore studies of recyclability using NAA showed that over 50% of the adsorbed copper could be removed in mild concentrations (0.01 M or 0.1 M) of either acid or base

  6. Coordination Environment of Copper Sites in Cu-CHA Zeolite Investigated by Electron Paramagnetic Resonance

    DEFF Research Database (Denmark)

    Godiksen, Anita; Stappen, Frederick N.; Vennestrøm, Peter N. R.

    2014-01-01

    Cu-CHA combines high activity for the selective catalytic reduction (SCR) reaction with better hydrothermal stability and selectivity compared to other copper-substituted zeolites. At the same time Cu-CHA offers an opportunity for unraveling the coordination environment of the copper centers since...... the zeolite framework is very simple with only one crystallographically independent tetrahedral site (T-site). In this study the results of an X-band electron paramagnetic resonance (EPR) investigation of ion-exchanged Cu-CHA zeolite with a Si/Al ratio of 14 ± 1 is presented. Different dehydration treatments...... of the EPR silent monomeric Cu2+ in copper-substituted zeolites is suggested to be copper species with an approximate trigonal coordination sphere appearing during the dehydration. After complete dehydration at 250 °C the majority of the EPR silent Cu2+ is suggested to exist as Cu2+–OH– coordinated to two...

  7. Geometry and Framework Interactions of Zeolite-Encapsulated Copper(II)-Histidine Complexes

    NARCIS (Netherlands)

    Weckhuysen, B.M.; Grommen, R.; Manikandan, P.; Gao, Y.; Shane, T.; Shane, J.J.; Schoonheydt, R.A.; Goldfarb, D.

    2000-01-01

    The coordination geometry of zeolite-encapsulated copper(II)-histidine (CuHis) complexes, prepared by ion exchange of the complexes from aqueous solutions into zeolite NaY, was determined by a combination of UV-vis-NIR diffuse reflectance spectroscopy (DRS), X-band EPR, electron-spin-echo envelope

  8. Radiochemical and thermal studies of the copper(II)-exchanged form of synthetic zeolite linde sieve A

    International Nuclear Information System (INIS)

    Banerjee, S.P.

    1978-01-01

    Synthetic zeolite Linde Sieve A displays a double ion-sieve action. Only small cations can penetrate the single 6-rings into the beta cages. The radiochemical and thermal studies of copper(II)-exchanges form of 4A shows evidence of hydrated copper(II) ions in the zeolite structure. (author)

  9. Oxidation of aromatic alcohols on zeolite-encapsulated copper amino acid complexes

    Energy Technology Data Exchange (ETDEWEB)

    Ernst, S.; Teixeira Florencio, J.M. [Kaiserslautern Univ. (Germany). Dept. of Chemistry, Chemical Technology

    1998-12-31

    Copper complexes of the amino acids histidine, arginine and lysine have been introduced into the supercages of zeolite Y and, for the first time, into the large intracrystalline cavities of zeolites EMT and MCM-22. The resulting host/guest compounds are characterized by X-ray powder diffraction, UV/VIS-spectroscopy in the diffuse reflectance mode and by catalytic tests in the liquid-phase oxidation of aromatic alcohols (viz. benzyl alcohol, 2- and 3-methylbenzyl alcohol and 2,5-dimethylbenzyl alcohol) with tertiary-butylhydroperoxide as oxidant. It was observed that intracrystalline copper-amino acid complexes possess remarkable catalytic activity, yielding the corresponding aromatic aldehydes and acids. (orig.)

  10. Blood biochemical changes in common carp (Cyprinus carpio Linnaeus, 1758 fed different levels of copper sulphate and zeolite

    Directory of Open Access Journals (Sweden)

    Arzu Aydın Uncumusaoğlu

    2018-02-01

    Full Text Available In this study, copper toxicity, was investigated after the addition of zeolite to the diet of common carps (Cyprinus carpio. The experiment included four groups with three replicates each. The 4 group feeds were [CuSO4; CuSO4 + Zeolite; Zeolite, and the control without CuSO4 or Zeolite with three replicates each. Fishes were kept in 80 L glass aquariums with 10 fishes with a mean weight of 60.6 ± 0.2 g. At the end of each period, a necropsy was performed on fishes from each treatment, and gross clinical signs were recorded. We found significant changes in the blood parameters of the common carps with or without different levels of zeolite and copper. Changes in cholesterol (CHOL, triglyceride (TG, low density lipoprotein (LDL, alanine aminotransferase (ALT, aspartate aminotransferase (AST, alkaline phosphatase (ALP, calcium (Ca2+, phosphorus (P+, sodium (Na+, potassium (K+, chloride (Cl-, magnesium (Mg2+, and ferrous (Fe+2 were also significant. Our results suggest that zeolite can be used in fish feeds at a rate of 40 mg/l to mitigate the toxic effects of copper.

  11. Hierarchical zeolites: progress on synthesis and characterization of mesoporous zeolite single crystal catalysts

    DEFF Research Database (Denmark)

    Kustova, Marina; Egeblad, Kresten; Christensen, Claus H.

    2007-01-01

    Recently, a new family of crystalline zeolitic materials was reported, the so-called mesoporous zeolite single crystals featuring individual zeolite single crystals with an additional noncrystalline mesopore system interconnected with the usual micropore system of the zeolite, resulting...... measurements. Additionally, the results of diffusion of n-hexadecane in conventional and mesoporous zeolites are presented. Isomerization and cracking of n-hexadecane was chosen as model test reaction for these materials. All results support that mesoporous zeolites are superior catalysts due to improved mass...... transport. Importantly, the mesoporous zeolites show significant improved resistance to poisoning by carbon formation....

  12. Removal of pyridine from liquid and gas phase by copper forms of natural and synthetic zeolites

    International Nuclear Information System (INIS)

    Rehakova, Maria; Fortunova, Lubica; Bastl, Zdenek; Nagyova, Stanislava; Dolinska, Silvia; Jorik, Vladimir; Jona, Eugen

    2011-01-01

    Zeoadsorbents on the basis of copper forms of synthetic zeolite ZSM5 and natural zeolite of the clinoptilolite type (CT) have been studied taking into account their environmental application in removing harmful pyridine (py) from liquid and gas phase. Sorption of pyridine by copper forms of zeolites (Cu-ZSM5 and Cu-CT) has been studied by CHN, X-ray photoelectron spectroscopy, X-ray powder diffractometry, FTIR spectroscopy, thermal analysis (TG, DTA and DTG) and analysis of the surface areas and the pore volumes by low-temperature adsorption of nitrogen. The results of thermal analyses of Cu-ZSM5, Cu-(py) x ZSM5, Cu-CT and Cu-(py) x CT zeolitic products with different composition (x depends on the experimental conditions of sorption of pyridine) clearly confirmed their different thermal properties as well as the sorption of pyridine. In the zeolitic pyridine containing samples the main part of the pyridine release process occurs at considerably higher temperatures than is the boiling point of pyridine, which proves strong bond and irreversibility of py-zeolite interaction. FTIR spectra of Cu-(py) x zeolite samples showed well resolved bands of pyridine. The results of thermal analysis and FTIR spectroscopy are in a good agreement with the results of other used methods.

  13. Zeolites as supports for transition-metal complexes

    Energy Technology Data Exchange (ETDEWEB)

    Le Van Mao, R

    1979-01-01

    The unique structural characteristics of the zeolites, including the presence of molecular-size cages and channels and of an internal electrostatic field, make them promising as supports for converting homogeneous to heterogeneous catalysts. The acidic sites on the zeolites may also contribute to catalysis of reactions, such as hydrocracking; may stabilize metal complexes in a highly disperse state; and may improve activity or selectivity. Recent studies on the synthesis of new types of zeolite-supported complexes of transition metals (TM), such as Co, Cu, Ag, Fe, Mo, Ru, Rh, Re, and Os, suggest the feasibility of the direct introduction of some TM complexes into the zeolitic cages during zeolite synthesis, especially during the crystallization phase. This method may considerably reduce the structural limitations associated with the incorporation of TM complexes into zeolites by conventional methods.

  14. Metal supported on natural zeolite as catalysts for conversion of ethanol to gasoline

    Directory of Open Access Journals (Sweden)

    Kristiani Anis

    2017-01-01

    Full Text Available A various of metal supported into natural zeolite was prepared via wet impregnation method. The transition metals impregnated are nickel, cobalt, copper and zinc. The catalytic properties both of physical and chemical properties were characterized by X-ray Diffraction (XRD, Thermo Gravimetri Analysis (TGA-Differential Scanning Calorimetry (DSC, Surface Area Analyzer-Porositymeter and also gravimetry method for acidity measurement following by the adsorption of organic bases. The results showed that different metals impregnated into natural zeolite affected physical and chemical properties, i.e. crystalinity, surface area, pore size, pore volume and acidity. Their catalytic activity was tested for conversion ethanol to gasoline and showed high conversion up to 80-90% with the aromatics as major product.

  15. Process for producing zeolite adsorbent and process for treating radioactive liquid waste with the zeolite adsorbent

    International Nuclear Information System (INIS)

    Motojima, K.; Kawamura, F.

    1984-01-01

    Zeolite is contacted with an aqueous solution containing at least one of copper, nickel, cobalt, manganese and zinc salts, preferably copper and nickel salts, particularly preferably copper salt, in such a form as sulfate, nitrate, or chloride, thereby adsorbing the metal on the zeolite in its pores by ion exchange, then the zeolite is treated with a water-soluble ferrocyanide compound, for example, potassium ferrocyanide, thereby forming metal ferrocyanide on the zeolite in its pores. Then, the zeolite is subjected to ageing treatment, thereby producing a zeolite adsorbent impregnated with metal ferrocyanide in the pores of zeolite. The adsorbent can selectively recover cesium with a high percent cesium removal from a radioactive liquid waste containing at least radioactive cesium, for example, a radioactive liquid waste containing cesium and such coexisting ions as sodium, magnesium, calcium and carbonate ions at the same time at a high concentration. The zeolite adsorbent has a stable adsorbability for a prolonged time

  16. Evaluation of the bactericidal characteristics of nano-copper oxide or functionalized zeolite coating for bio-corrosion control in concrete sewer pipes

    International Nuclear Information System (INIS)

    Haile, T.; Nakhla, G.; Allouche, E.; Vaidya, S.

    2010-01-01

    The bactericidal characteristics of nano-copper oxide or functionalized zeolite coated concrete pipes against Acidithiobacillus thiooxidans were studied by measuring the temporal variation of bacterial dry cell weight measurement, cellular Adenosine Triphosphate production, as well as oxygen uptake rate of the aforementioned bacterium. Uncorroded (UC), severely corroded (SC), and moderately corroded (MC) concrete pipes were electrochemically coated with a nano-copper oxide, while another uncorroded concrete pipe was used to apply functionalized zeolite coating (Z2). Specimens were characterized by field emission-scanning electron microscopy, and optical microscopy. Oxygen uptake rate of the bacterium was the highest in UC followed by the MC. Oxygen uptake rate and cellular Adenosine Triphosphate decreased progressively in Z2 and SC throughout the duration of the experiment due to decline in live bacterial cell. The maximum bacterial specific growth rate was 1.1 x 10 -2 day -1 for both UC and MC, with a decay rates varying from 1.4 x 10 -2 to 2.6 x 10 -2 day -1 . The minimum concentration limits for the inhibition of the bacterium in the nano-copper oxide coated concrete pipes ranged from 2.3 mg to 2.6 mg Cu per mg dry cell weight.

  17. Site-Specific Reactivity of Copper Chabazite Zeolites with Nitric Oxide, Ammonia, and Oxygen

    DEFF Research Database (Denmark)

    Godiksen, Anita; Isaksen, Oliver L.; Rasmussen, Søren B.

    2018-01-01

    In-situ electron paramagnetic resonance (EPR) spectroscopy was applied to dilute copper chabazite (CHA) zeolites under gas flows relevant for the selective catalytic reduction of NO with ammonia (NH3-SCR). Under both reducing and oxidizing conditions, we observed differences in reactivity between...

  18. Thermochemical properties of copper forms of zeolite ZSM5 containing dimethylethylenediamine

    International Nuclear Information System (INIS)

    Cuvanova, S.; Rehakova, M.; Finocchiaro, P.; Pollicino, A.; Bastl, Z.; Nagyova, S.; Fajnor, V.S.

    2007-01-01

    Synthetic zeolite ZSM5 and its copper forms containing N,N-dimethylethylenediamine (dmen) have been investigated by CHN, energy dispersive spectroscopy (EDS) analysis, X-ray powder diffractometry, X-ray photoelectron spectroscopy and continuous waves hydrogen nuclear magnetic resonance (CW 1 H NMR) spectroscopy. Thermal properties have been studied by methods of thermal analysis-TG, DTA and DTG in the temperature range 20-1000 deg. C in air atmosphere. Mass spectroscopy method was used for the study of the released gas products of thermal decomposition. The results of thermal analyses of two zeolitic samples Cu-ZSM5 and Cu(dmen) x ZSM5 (x depends on the mode of preparation) demonstrated their different thermal properties. The main part of the decomposition process of the samples Cu(dmen) x ZSM5 occurs at considerably higher temperatures than the boiling point of dimethylethylenediamine, proving strong bond and irreversibility of dmen-zeolite interaction. According to the results of mass spectroscopy the decomposition process in inert atmosphere is characterized by the development of a large spectrum of products with atomic mass from 18 to 447 atomic mass units as a consequence of the catalytic effect of the silicate surface

  19. CO hydrogenation on zeolite-supported Ru: Effect of neutralizing cations

    International Nuclear Information System (INIS)

    Oukaci, R.; Wu, J.C.S.; Goodwin, J.G. Jr.

    1986-01-01

    Previous results for zeolite-supported Ru prepared by ion exchange suggested a possible effect of the nature and concentration of the neutralizing cations in the zeolite on the catalytic properties of the metal. However, the interpretation of these results was complicated by the fact that a series of zeolites with different Si/Al ratios was used. The present study was undertaken to investigate systematically the influence of the nature of alkali neutralizing cations on CO hydrogenation over ion-exchanged Y-zeolite-supported ruthenium catalysts

  20. Copper(II)–imida‐salen Complexes Encapsulated into NaY Zeolite for Oxidations Reactions

    DEFF Research Database (Denmark)

    Kuźniarska‐Biernacka, Iwona; Carvalho, M. Alice; Rasmussen, Søren Birk

    2013-01-01

    The oxidation of phenol, cychohexanol and hydroquinone has been screened in the presence of copper(II) complexes with the Schiff‐base salen ligand, 1,5‐bis[(E)‐5‐chloro‐2‐hydroxybenzylideneamino]‐1H‐imidazole‐4‐carbonitrile, and encapsulated into NaY zeolite by using two different methods. The new...

  1. Supported Zeolite Beta Layers via an Organic Template-Free Preparation Route

    Directory of Open Access Journals (Sweden)

    Stephanie Reuss

    2018-01-01

    Full Text Available Layers of high silica zeolites, synthesized with an organic structure directing agent (OSDA and grown onto porous support structures, frequently suffer from the thermal stress during the removal of OSDA via the calcination process. The different thermal expansion coefficients of the zeolite and the support material, especially when stainless steel is used as a support, causes enormous tension resulting in defect formation in the zeolite layer. However, the calcination is an easy procedure to decompose the OSDA in the pore system of the zeolite. Recently, methods to synthesize zeolite beta without the use of an organic structure directing agent have been described. In the present study, a seed-directed synthesis is used to prepare OSDA-free zeolite beta layers on stainless steel supports via an in situ preparation route. For the application as membrane, a porous stainless steel support has been chosen. The beta/stainless steel composites are characterized by X-ray diffraction (XRD and scanning electron microscopy (SEM. To prove its possible application as a membrane, the beta/stainless steel composites were also tested by single gas permeances of H2, He, CO2, N2, and CH4.

  2. Supported Zeolite Beta Layers via an Organic Template-Free Preparation Route.

    Science.gov (United States)

    Reuss, Stephanie; Sanwald, Dirk; Schülein, Marion; Schwieger, Wilhelm; Al-Thabaiti, Shaeel A; Mokhtar, Mohamed; Basahel, Sulaiman N

    2018-01-21

    Layers of high silica zeolites, synthesized with an organic structure directing agent (OSDA) and grown onto porous support structures, frequently suffer from the thermal stress during the removal of OSDA via the calcination process. The different thermal expansion coefficients of the zeolite and the support material, especially when stainless steel is used as a support, causes enormous tension resulting in defect formation in the zeolite layer. However, the calcination is an easy procedure to decompose the OSDA in the pore system of the zeolite. Recently, methods to synthesize zeolite beta without the use of an organic structure directing agent have been described. In the present study, a seed-directed synthesis is used to prepare OSDA-free zeolite beta layers on stainless steel supports via an in situ preparation route. For the application as membrane, a porous stainless steel support has been chosen. The beta/stainless steel composites are characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM). To prove its possible application as a membrane, the beta/stainless steel composites were also tested by single gas permeances of H₂, He, CO₂, N₂, and CH₄.

  3. Recent progress in the direct synthesis of hierarchical zeolites: synthetic strategies and characterization methods

    KAUST Repository

    Liu, Zhaohui

    2017-06-16

    Hierarchically structured zeolites combine the merits of microporous zeolites and mesoporous materials to offer enhanced molecular diffusion and mass transfer without compromising the inherent catalytic activities and selectivity of zeolites. This short review gives an introduction to the synthesis strategies for hierarchically structured zeolites with emphasis on the latest progress in the route of ‘direct synthesis’ using various templates. Several characterization methods that allow us to evaluate the ‘quality’ of complex porous structures are also introduced. At the end of this review, an outlook is given to discuss some critical issues and challenges regarding the development of novel hierarchically structured zeolites as well as their applications.

  4. Performance Evaluations of Ion Exchanged Zeolite Membranes on Alumina Supports

    Energy Technology Data Exchange (ETDEWEB)

    Bhave, Ramesh R. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Jubin, Robert Thomas [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Spencer, Barry B. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Nair, Sankar [Georgia Inst. of Technology, Atlanta, GA (United States)

    2017-08-27

    This report describes the synthesis and evaluation of molecular sieve zeolite membranes to separate and concentrate tritiated water (HTO) from dilute HTO-bearing aqueous streams. In the first phase of this effort, several monovalent and divalent cation-exchanged silico alumino phosphate (SAPO-34) molecular sieve zeolite membranes were synthesized on disk supports and characterized with gas and vapor permeation measurements. In the second phase, Linde Type A (LTA) zeolite membranes were synthesized in disk and tubular supports. The pervaporation process performance was evaluated for the separation and concentration of tritiated water.

  5. Halloysite nanotube-based electrospun ceramic nanofibre mat: a novel support for zeolite membranes

    Science.gov (United States)

    Chen, Zhuwen; Zeng, Jiaying; Lv, Dong; Gao, Jinqiang; Zhang, Jian; Bai, Shan; Li, Ruili; Hong, Mei; Wu, Jingshen

    2016-12-01

    Some key parameters of supports such as porosity, pore shape and size are of great importance for fabrication and performance of zeolite membranes. In this study, we fabricated millimetre-thick, self-standing electrospun ceramic nanofibre mats and employed them as a novel support for zeolite membranes. The nanofibre mats were prepared by electrospinning a halloysite nanotubes/polyvinyl pyrrolidone composite followed by a programmed sintering process. The interwoven nanofibre mats possess up to 80% porosity, narrow pore size distribution, low pore tortuosity and highly interconnected pore structure. Compared with the commercial α-Al2O3 supports prepared by powder compaction and sintering, the halloysite nanotube-based mats (HNMs) show higher flux, better adsorption of zeolite seeds, adhesion of zeolite membranes and lower Al leaching. Four types of zeolite membranes supported on HNMs have been successfully synthesized with either in situ crystallization or a secondary growth method, demonstrating good universality of HNMs for supporting zeolite membranes.

  6. Antimicrobial properties of zeolite-X and zeolite-A ion-exchanged with silver, copper, and zinc against a broad range of microorganisms.

    Science.gov (United States)

    Demirci, Selami; Ustaoğlu, Zeynep; Yılmazer, Gonca Altın; Sahin, Fikrettin; Baç, Nurcan

    2014-02-01

    Zeolites are nanoporous alumina silicates composed of silicon, aluminum, and oxygen in a framework with cations, water within pores. Their cation contents can be exchanged with monovalent or divalent ions. In the present study, the antimicrobial (antibacterial, anticandidal, and antifungal) properties of zeolite type X and A, with different Al/Si ratio, ion exchanged with Ag(+), Zn(2+), and Cu(2+) ions were investigated individually. The study presents the synthesis and manufacture of four different zeolite types characterized by scanning electron microscopy and X-ray diffraction. The ion loading capacity of the zeolites was examined and compared with the antimicrobial characteristics against a broad range of microorganisms including bacteria, yeast, and mold. It was observed that Ag(+) ion-loaded zeolites exhibited more antibacterial activity with respect to other metal ion-embedded zeolite samples. The results clearly support that various synthetic zeolites can be ion exchanged with Ag(+), Zn(2+), and Cu(2+) ions to acquire antimicrobial properties or ion-releasing characteristics to provide prolonged or stronger activity. The current study suggested that zeolite formulations could be combined with various materials used in manufacturing medical devices, surfaces, textiles, or household items where antimicrobial properties are required.

  7. Crystallization and melting behavior of isotactic polypropylene composites filled by zeolite supported β-nucleator

    International Nuclear Information System (INIS)

    Jiang, Juan; Li, Gu; Tan, Nanshu; Ding, Qian; Mai, Kancheng

    2012-01-01

    Highlights: ► The supported calcium pimelate β-zeolite was prepared. ► The β-nucleation of zeolite was enhanced dramatically through reaction. ► High β-phase content iPP composites were obtained by introducing the β-zeolite into iPP. - Abstract: In order to prepare the zeolite filled β-iPP composites, the calcium pimelate as β-nucleator supported on the surface of zeolite (β-zeolite) was prepared by the interaction between calcified zeolite and pimelic acid. The β-nucleation, crystallization behavior and melting characteristic of zeolite, calcified zeolite and β-zeolite filled iPP composites were investigated by differential scanning calorimetry and wide-angle X-ray diffractometer. The results indicated that addition of the zeolite and calcified zeolite as well as β-zeolite increased the crystallization temperature of iPP. The zeolite and calcified zeolite filled iPP composites mainly crystallized in the α-crystal form and the strong β-heterogeneous nucleation of β-zeolite results in the formation of only β-crystal in β-zeolite filled iPP composites. The zeolite filled β-iPP composites with high β-crystal contents (above 0.90) can be easily obtained by adding β-zeolite into iPP matrix.

  8. Adsorption Cooling System Using Metal-Impregnated Zeolite-4A

    Directory of Open Access Journals (Sweden)

    Somsuk Trisupakitti

    2016-01-01

    Full Text Available The adsorption cooling systems have been developed to replace vapor compression due to their benefits of being environmentally friendly and energy saving. We prepared zeolite-4A and experimental cooling performance test of zeolite-water adsorption system. The adsorption cooling test-rig includes adsorber, evaporator, and condenser which perform in vacuum atmosphere. The maximum and minimum water adsorption capacity of different zeolites and COP were used to assess the performance of the adsorption cooling system. We found that loading zeolite-4A with higher levels of silver and copper increased COP. The Cu6%/zeolite-4A had the highest COP at 0.56 while COP of zeolite-4A alone was 0.38. Calculating the acceleration rate of zeolite-4A when adding 6% of copper would accelerate the COP at 46%.

  9. Electrochemical water splitting using nano-zeolite Y supported tungsten oxide electrocatalysts

    Science.gov (United States)

    Anis, Shaheen Fatima; Hashaikeh, Raed

    2018-02-01

    Zeolites are often used as supports for metals and metal oxides because of their well-defined microporous structure and high surface area. In this study, nano-zeolite Y (50-150 nm range) and micro-zeolite Y (500-800 nm range) were loaded with WO3, by impregnating the zeolite support with ammonium metatungstate and thermally decomposing the salt thereafter. Two different loadings of WO3 were studied, 3 wt.% and 5 wt.% with respect to the overall catalyst. The prepared catalysts were characterized for their morphology, structure, and surface areas through scanning electron microscope (SEM), XRD, and BET. They were further compared for their electrocatalytic activity for hydrogen evolution reaction (HER) in 0.5 M H2SO4. On comparing the bare micro-zeolite particles with the nano-form, the nano-zeolite Y showed higher currents with comparable overpotentials and lower Tafel slope of 62.36 mV/dec. WO3 loading brought about a change in the electrocatalytic properties of the catalyst. The overpotentials and Tafel slopes were observed to decrease with zeolite-3 wt.% WO3. The smallest overpotential of 60 mV and Tafel slope of 31.9 mV/dec was registered for nano-zeolite with 3 wt.% WO3, while the micro-zeolite gave an overpotential of 370 mV and a Tafel slope of 98.1 mV/dec. It was concluded that even with the same metal oxide loading, nano-zeolite showed superior performance, which is attributed to its size and hence easier escape of hydrogen bubbles from the catalyst.

  10. Templating mesoporous zeolites

    DEFF Research Database (Denmark)

    Egeblad, Kresten; Christensen, Christina Hviid; Kustova, Marina

    2008-01-01

    The application of templating methods to produce zeolite materials with hierarchical bi- or trimodal pore size distributions is reviewed with emphasis on mesoporous materials. Hierarchical zeolite materials are categorized into three distinctly different types of materials: hierarchical zeolite...... crystals, nanosized zeolite crystals, and supported zeolite crystals. For the pure zeolite materials in the first two categories, the additional meso- or macroporosity can be classified as being either intracrystalline or intercrystalline, whereas for supported zeolite materials, the additional porosity...... originates almost exclusively from the support material. The methods for introducing mesopores into zeolite materials are discussed and categorized. In general, mesopores can be templated in zeolite materials by use of solid templating, supramolecular templating, or indirect templating...

  11. Using copper hexacyanoferrate (II) impregnated zeolite for cesium removal from radioactive liquid waste

    International Nuclear Information System (INIS)

    Fumio, K.; Kenji, M.

    1982-01-01

    Experiments were performed to obtain fundamental data on cesium ion removal characteristics of metal hexacyanoferrate (II) impregnated zeolite in radioactive liquid waste containing a large amount of sodium sulfate. Copper hexacyanoferrate (II) impregnated zeolite (CuFZ) was prepared and showed a high selectivity for cesium ion. The material was suitable for use in an ion exchange column. This exchanger could selectively and efficiently remove the cesium even if there is 15 wt% Na 2 SO 4 in the solution. Cesium removal ability and stability of CuFZ were excellent over a wide pH range between 1.5 and 10. The cesium ion exchange ability was not influenced by the presence of the alkali metal ions, calcium and magnesium, and carbonate ions even at concentrations 25 times greater than the cesium ion. However, since ammonium ion behaves similarly to cesium ion and interrupts latter ion adsorption, the presence of ammonium ion is not desirable. The CuFZ offers the possibility of separating and removing cesium from liquid wastes produced in facilities handling radioactive materials

  12. Progress on Zeolite-membrane-aided Organic Acid Esterification

    Science.gov (United States)

    Makertiharta, I. G. B. N.; Dharmawijaya, P. T.

    2017-07-01

    Esterification is a common route to produce carboxylic acid esters as important intermediates in chemical and pharmaceutical industries. However, the reaction is equilibrium limited and needs to be driven forward by selective removal one of the products. There have been some efforts to selectively remove water from reaction mixture via several separation processes (such as pervaporation and reactive distillation). Integrated pervaporation and esterification has gained increasing attention towards. Inorganic zeolite is the most popular material for pervaporation due to its high chemical resistant and separation performance towards water. Zeolite also has proven to be an effective material in removing water from organic compound. Zeolite can act not only as selective layer but also simultaneously act as a catalyst on promoting the reaction. Hence, there are many configurations in integrating zeolite membrane for esterification reaction. As a selective layer to remove water from reaction mixture, high Si/Al zeolite is preferred to enhance its hydrophilicity. However, low Si/Al zeolite is unstable in acid condition due to dealumination thus eliminate its advantages. As a catalyst, acid zeolites (e.g. H-ZSM-5) provide protons for autoprotolysis of the carboxylic acid similar to other catalyst for esterification (e.g. inorganic acid, and ion exchange resins). There are many studies related to zeolite membrane aided esterification. This paper will give brief information related to zeolite membrane role in esterification and also research trend towards it.

  13. Synthesis and characterization of alumina application in support of zeolite membrane

    International Nuclear Information System (INIS)

    Barbosa, A.S.; Rodrigues, M.G.F.

    2012-01-01

    Much interest has been aroused in process applications using zeolite membrane. The physicochemical properties of the support have a strong effect on the quality of zeolite membrane. This work is to synthesize and characterize alumina for use as a support for zeolite membrane. In this work was synthesized α-alumina: 40% alumina, 0.2% for PABA, 0.5% oleic acid and 59.3% ethyl alcohol. The mixture was ground in ball mill and placed in an oven for 24 hours at 60 °C, allowed to stand for 24h. The pressing was performed with 4 tons. The pressed material was subjected to sintering at 1400 °C/hour. The samples were characterized by EDX, XRD and SEM. The results for the media by XRD showed that they are crystalline and pure. By EDX was observed that the supports consist essentially of alumina. (author)

  14. Enhanced photocatalytic activity of supported TiO{sub 2} by selective surface modification of zeolite Y

    Energy Technology Data Exchange (ETDEWEB)

    Guesh, Kiros [Chemistry-Department, Addis Ababa University, P.O. Box 1176, Addis Ababa (Ethiopia); Mizan-Tepi University, P.O. Box 260, Mizan-Teferi (Ethiopia); Márquez-Álvarez, Carlos [Instituto de Catálisis y Petroleoquímica, CSIC, c/Marie Curie 2, 28049 Madrid (Spain); Chebude, Yonas [Chemistry-Department, Addis Ababa University, P.O. Box 1176, Addis Ababa (Ethiopia); Díaz, Isabel, E-mail: idiaz@icp.csic.es [Chemistry-Department, Addis Ababa University, P.O. Box 1176, Addis Ababa (Ethiopia); Instituto de Catálisis y Petroleoquímica, CSIC, c/Marie Curie 2, 28049 Madrid (Spain)

    2016-08-15

    Highlights: • XPS analysis confirmed that 50% of the Al was removed from the surface of zeolite Y. • Loaded TiO{sub 2} on the treated zeolites showed 12 times higher TORm than the parent zeolite. • Supported TiO{sub 2} showed very low leaching of TiO{sub 2} nanoparticles than non supported. - Abstract: Zeolite Y was treated using ammonium acetate and ammonium fluoride sequentially. As a consequence the aluminum from the surface was selectively removed. Then, loading with TiO{sub 2} (20 wt%) led to a final photocatalyst. The samples were characterized by X-ray diffraction (XRD), elemental analysis (ICP-OES), N{sub 2} adsorption, diffuse reflectance UV–vis spectroscopy (DRS), photoluminescence spectroscopy (PL), and X-ray photoelectron spectroscopy (XPS). It was found that 50% of the Al atoms were removed from the surface of the zeolite without affecting the framework structure. The TiO{sub 2}/treated zeolite sample yielded 92% photocatalytic degradation of 10 ppm methyl orange (MO), a model pollutant, while the TiO{sub 2}/parent zeolite converted only 7.6%. The mass normalized turnover rate (TOR{sub m}) of the treated zeolite loaded with TiO{sub 2} was about 12 times higher than that of the parent zeolite loaded with the same amount of TiO{sub 2} precursor. This higher photocatalytic activity of the TiO{sub 2} supported on treated zeolite can be attributed to a more efficient interaction of the TiO{sub 2} with the zeolite leading to higher adsorption capacity. Reusability of the photocatalysts was assessed by performing three consecutive reaction cycles that showed no significant loss of photocatalytic activity.

  15. Removal of Cu(II) from leachate using natural zeolite as a landfill liner material.

    Science.gov (United States)

    Turan, N Gamze; Ergun, Osman Nuri

    2009-08-15

    All hazardous waste disposal facilities require composite liner systems to act as a barrier against migration of contaminated leachate into the subsurface environment. Removal of copper(II) from leachate was studied using natural zeolite. A serial of laboratory systems on bentonite added natural zeolite was conducted and copper flotation waste was used as hazardous waste. The adsorption capacities and sorption efficiencies were determined. The sorption efficiencies increased with increasing natural zeolite ratio. The pseudo-first-order, the pseudo-second-order, Elovich and the intra-particle diffusion kinetic models were used to describe the kinetic data to estimate the rate constants. The second-order model best described adsorption kinetic data. The results indicated that natural zeolite showed excellent adsorptive characteristics for the removal of copper(II) from leachate and could be used as very good liner materials due to its high uptake capacity and the abundance in availability.

  16. Removal of Cu(II) from leachate using natural zeolite as a landfill liner material

    International Nuclear Information System (INIS)

    Turan, N. Gamze; Ergun, Osman Nuri

    2009-01-01

    All hazardous waste disposal facilities require composite liner systems to act as a barrier against migration of contaminated leachate into the subsurface environment. Removal of copper(II) from leachate was studied using natural zeolite. A serial of laboratory systems on bentonite added natural zeolite was conducted and copper flotation waste was used as hazardous waste. The adsorption capacities and sorption efficiencies were determined. The sorption efficiencies increased with increasing natural zeolite ratio. The pseudo-first-order, the pseudo-second-order, Elovich and the intra-particle diffusion kinetic models were used to describe the kinetic data to estimate the rate constants. The second-order model best described adsorption kinetic data. The results indicated that natural zeolite showed excellent adsorptive characteristics for the removal of copper(II) from leachate and could be used as very good liner materials due to its high uptake capacity and the abundance in availability.

  17. Vanadia supported on zeolites for SCR of NO by ammonia

    DEFF Research Database (Denmark)

    Putluru, Siva Sankar Reddy; Riisager, Anders; Fehrmann, Rasmus

    2010-01-01

    , acidity and micropore structure of the support. Apparently the support hosted the potassium oxide on the acid sites, thereby protecting the active vanadium species from poisoning. Zeolite based catalysts might therefore prove useful for SCR of NO in alkali-containing flue gases from, e.g. biomass fired...

  18. Investigation of PCDD/F emissions from mobile source diesel engines: impact of copper zeolite SCR catalysts and exhaust aftertreatment configurations.

    Science.gov (United States)

    Liu, Z Gerald; Wall, John C; Barge, Patrick; Dettmann, Melissa E; Ottinger, Nathan A

    2011-04-01

    This study investigated the impact of copper zeolite selective catalytic reduction (SCR) catalysts and exhaust aftertreatment configurations on the emissions of polychlorinated dibenzo-p-dioxins (PCDDs) and polychlorinated dibenzofurans (PCDFs) from mobile source diesel engines. Emissions of PCDD/Fs, reported as the weighted sum of 17 congeners called the toxic equivalency quotient (TEQ), were measured using a modified EPA Method 0023A in the absence and presence of exhaust aftertreatment. Engine-out emissions were measured as a reference, while aftertreatment configurations included various combinations of diesel oxidation catalyst (DOC), diesel particulate filter (DPF), Cu-zeolite SCR, Fe-zeolite SCR, ammonia oxidation catalyst (AMOX), and aqueous urea dosing. In addition, different chlorine concentrations were evaluated. Results showed that all aftertreatment configurations reduced PCDD/F emissions in comparison to the engine-out reference, consistent with reduction mechanisms such as thermal decomposition or combined trapping and hydrogenolysis reported in the literature. Similarly low PCDD/F emissions from the DOC-DPF and the DOC-DPF-SCR configurations indicated that PCDD/F reduction primarily occurred in the DOC-DPF with no noticeable contribution from either the Cu- or Fe-zeolite SCR systems. Furthermore, experiments performed with high chlorine concentration provided no evidence that chlorine content has an impact on the catalytic synthesis of PCDD/Fs for the chlorine levels investigated in this study.

  19. Enhanced Activity of Nanocrystalline Zeolites for Selective Catalytic Reduction of NOx

    International Nuclear Information System (INIS)

    Sarah C. Larson; Vicki H. Grassian

    2006-01-01

    Nanocrystalline zeolites with discrete crystal sizes of less than 100 nm have different properties relative to zeolites with larger crystal sizes. Nanocrystalline zeolites have improved mass transfer properties and very large internal and external surface areas that can be exploited for many different applications. The additional external surface active sites and the improved mass transfer properties of nanocrystalline zeolites offer significant advantages for selective catalytic reduction (SCR) catalysis with ammonia as a reductant in coal-fired power plants relative to current zeolite based SCR catalysts. Nanocrystalline NaY was synthesized with a crystal size of 15-20 nm and was thoroughly characterized using x-ray diffraction, electron paramagnetic resonance spectroscopy, nitrogen adsorption isotherms and Fourier Transform Infrared (FT-IR) spectroscopy. Copper ions were exchanged into nanocrystalline NaY to increase the catalytic activity. The reactions of nitrogen dioxides (NO x ) and ammonia (NH 3 ) on nanocrystalline NaY and CuY were investigated using FT-IR spectroscopy. Significant conversion of NO 2 was observed at room temperature in the presence of NH 3 as monitored by FT-IR spectroscopy. Copper-exchanged nanocrystalline NaY was more active for NO 2 reduction with NH 3 relative to nanocrystalline NaY

  20. Decomposition of NO on Cu-loaded zeolites

    Energy Technology Data Exchange (ETDEWEB)

    Sepulveda-Escribano, A; Marquez-Alvarez, C; Rodriquez-Ramos, I; Fierro, J L.G. [Instituto de Catalisis y Petroleoquimica, Madrid (Spain); Guerrero-Ruiz, A [Departamento de Quimica Inorganica, UNED, Madrid (Spain)

    1993-05-26

    Two copper ion-exchanged zeolites, Cu/NaY and Cu/NaZSM-5 have been studied by several techniques (TPR, TPD of NO, IR spectroscopy of adsorbed NO and XPS) and their catalytic activity for NO-decomposition have been determined under dynamic conditions. The results obtained here show that copper is stabilized as Cu[sup +] in Cu/NaZSM-5 after calcination in air at 673K, while in Cu/NaY the initial Cu[sup +]-ions are easier oxidized to Cu[sup 2+], this leading to a completely different catalytic behavior in the reaction of NO-decomposition. So, whereas the Cu/NaZSM-5 exhibits a high NO-conversion at the reaction temperatures (573 and 873K), the parent Cu/NaY zeolite becomes deactivated in the first stages of reaction.

  1. Hydrodeoxygenation of Methyl Laurate over Ni Catalysts Supported on Hierarchical HZSM-5 Zeolite

    Directory of Open Access Journals (Sweden)

    Nana Li

    2017-12-01

    Full Text Available The hierarchical HZSM-5 zeolite was prepared successfully by a simple NaOH treatment method. The concentration of NaOH solution was carefully tuned to optimal the zeolite acidity and pore structure. Under NaOH treatment conditions, a large number of mesopores, which interconnected with the retained micropores, were created to facilitate mass transfer performance. There are very good correlations between the decline of the relative zeolite crystallinity and the loss of micropores volume. The Ni nanoclusters were uniformly confined in the mesopores of hierarchical HZSM-5 by the excessive impregnation method. The direct deoxygenation in N2 and hydrodeoxygenation in H2 of the methyl laurate were compared respectively over the Ni/HZSM-5 catalysts. In the N2 atmosphere, the deoxygenation rate of the methyl laurate on the Ni/HZSM-5 catalyst is relatively slow. In the presence of H2, the synergistic effect between the hydrogenation function of the metal and the acid function of the zeolite supports can make the deoxygenation level more obvious. The yield of hydrocarbon products gradually reached the maximum with the appropriate treatment concentration of 1M NaOH, which could be attributed to the improved mass transfer in the hierarchical HZSM-5 supports.

  2. Selective Ring Opening of 1-Methylnaphthalene Over NiW-Supported Catalyst Using Dealuminated Beta Zeolite.

    Science.gov (United States)

    Kim, Eun-Sang; Lee, You-Jin; Kim, Jeong-Rang; Kim, Joo-Wan; Kim, Tae-Wan; Chae, Ho-Jeong; Kim, Chul-Ung; Lee, Chang-Ha; Jeong, Soon-Yong

    2016-02-01

    Nanoporous Beta zeolite was dealuminated by weak acid treatment for reducing the acidity. Bi-functional catalysts were prepared using commercial Beta zeolites and the dealuminated zeolites for acidic function, NiW for metallic function. 1-Methylnaphthalene was selected as a model compound for multi-ring aromatics in heavy oil, and its selective ring opening reaction has been investigated using the prepared bi-functional catalysts with different acidity in fixed bed reaction system. The dealuminated Beta zeolites, which crystal structure and nanoporosity were maintained, showed the higher SiO2/Al2O3 ratio and smaller acidity than their original zeolite. NiW-supported catalyst using the dealuminated Beta zeolite with SiO2/Al203 mole ratio of 55 showed the highest performance for the selective ring opening. The acidity of catalyst seemed to play an important role as active sites for the selective ring opening of 1-methylnaphthalene but there should be some optimum catalyst acidity for the reaction. The acidity of Beta zeolite could be controlled by the acid treatment and the catalyst with the optimum acidity for the selective ring opening could be prepared.

  3. Catalytic reduction of NOx in gasoline engine exhaust over copper- and nickel-exchanged X-zeolite catalysts

    International Nuclear Information System (INIS)

    Bhattacharyya, S.; Das, R.K.

    2001-01-01

    Catalytic removal of NO x in engine exhaust gases can be accomplished by non-selective reduction, selective reduction and decomposition. Noble metals are extensively used for non-selective reduction of NO x and up to 90% of engine NO x emissions can be reduced in a stoichiometric exhaust. This requirement of having the stoichiometric fuel-air ratio acts against efficiency improvement of engines. Selective NO x reduction in the presence of different reductants such as, NH 3 , urea or hydrocarbons, requires close control of the amount of reductant being injected which otherwise may be emitted as a pollutant. Catalytic decomposition is the best option for NO x removal. Nevertheless, catalysts which are durable, economic and active for NO x reduction at normal engine exhaust temperature ranges are still being investigated. Three catalysts based on X-zeolite have been developed by exchanging the Na+ ion with copper, nickel and copper-nickel metal ions and applied to the exhaust of a stationary gasoline engine to explore their potential for catalytic reduction of NO x under a wide range of engine and exhaust conditions. Some encouraging results have been obtained. The catalyst Cu-X exhibits much better NO x reduction performance at any temperature in comparison to Cu-Ni-X and Ni-X; while Cu-Ni-X catalyst exhibits slightly better performance than Ni-X catalyst. Maximum NO x efficiency achieved with Cu-X catalyst is 59.2% at a space velocity (sv) of 31 000 h -1 ; while for Cu-Ni-X and Ni-X catalysts the equivalent numbers are 60.4% and 56% respectively at a sv of 22 000 h -1 . Unlike noble metals, the doped X-zeolite catalysts exhibit significant NO x reduction capability for a wide range of air/fuel ratio and with a slower rate of decline as well with increase in air/fuel ratio. (author)

  4. Polypropylene obtained through zeolite supported catalysts

    Directory of Open Access Journals (Sweden)

    Queli C. Bastos

    2004-01-01

    Full Text Available Propylene polymerizations were carried out with f2C(Flu(CpZrCl2 and SiMe2(Ind2ZrCl2 catalysts supported on silica, zeolite sodic mordenite (NaM and acid mordenite (HM. The polymerizations were performed at different temperatures and varying aluminium/zirconium molar ratios ([Al]/[Zr]. The effect of these reaction parameters on the catalyst activity was investigated using a proposed statistical experimental planning. In the case of f2C(Flu(CpZrCl2, SiO2 and NaM were used as support and the catalyst performance evaluated using toluene and pentane as polymerization solvent. The molecular weight, molecular weight distribution, melting point and crystallinity of the polymers were examined. The results indicate very high activities for the syndiospecific heterogeneous system. Also, the polymers obtained had superior Mw and stereoregularity.

  5. Polypropylene obtained through zeolite supported catalysts

    International Nuclear Information System (INIS)

    Bastos, Queli C.; Marques, Maria de Fatima V.

    2004-01-01

    Propylene polymerizations were carried out with φ 2 C(Flu)(Cp)ZrCl 2 and SiMe 2 (Ind)2ZrCl 2 catalysts supported on silica, zeolite sodic mordenite (NaM) and acid mordenite (HM). The polymerizations were performed at different temperatures and varying aluminium/zirconium molar ratios ([Al]/[Zr]). The effect of these reaction parameters on the catalyst activity was investigated using a proposed statistical experimental planning. In the case of f 2 C(Flu)(Cp)ZrCl 2 , SiO 2 and NaM were used as support and the catalyst performance evaluated using toluene and pentane as polymerization solvent. The molecular weight, molecular weight distribution, melting point and crystallinity of the polymers were examined. The results indicate very high activities for the syndiospecific heterogeneous system. Also, the polymers obtained had superior Mw and stereo regularity. (author)

  6. Zeolite ZSM5 catalysts for abatement of nitrogen oxide

    Energy Technology Data Exchange (ETDEWEB)

    Ganemi, Bager

    1999-07-01

    Airborne pollutants from the combustion of fossil fuels are a global problem. Emission of nitrogen oxides (NO{sub x}) is increasing with the worldwide increase in the use of energy. Atmospheric and photochemical reactions link nitrogen oxides to hydrocarbons and tropospheric ozone. The emission of NO{sub x} has to be tackled urgently in order to limit the harmful effects of anthropogenic activity on the environment. The subject of this thesis is catalytic nitrogen oxide abatement through direct decomposition and reduction by methane over ion-exchanged zeolite ZSM5. The work covers catalytic conversion and surface intermediates, including correlations with the level of exchanged Cu{sup 2+} cations and Ni{sup 2+} or Pd{sup 2+} co-cations. Special attention is given to the aluminium content of the support and changes in structural parameters. It was found that NO{sub x} conversion over cation-exchanged ZSM5 is strongly influenced by the ion-exchange procedure and by the above material parameters. Characterization of Cu-ZSM5 reveals that approximately two molecules of water per Cu{sup 2+} ion desorb at temperatures between 150 and 350 Deg C, in addition to the conventional dehydration at lower temperatures. The desorbed water comes from the decomposition of Cu(OH){sub 2}. Decomposition of hydroxylated copper ions results in the formation Of Cu{sup 2+}-O-Cu{sup 2+} dimers, which are suggested to be the active sites for catalytic decomposition of NO. Acid sites are important for the dispersion of copper ions on the catalyst surface. Acid sites are also important for the interaction between copper species and the zeolite. Increased acidity leads to a stronger interaction between the exchanged cation and the framework, i.e. the exchanged cations become more resistant to mobility. The stronger bond between the exchanged cations and lattice oxygen also prevents dealumination of the catalyst and decreases the thermal expansion at higher temperatures. The temperature of

  7. Characterization of extra-framework species in zeolites

    DEFF Research Database (Denmark)

    Andersen, Casper Welzel

    Sometimes it is difficult to see the wood for the trees. Crystallography is a great tool to take a step back, to observe and analyze the effects and implications caused by atoms and molecules in a crystalline material. In catalysis, the goal is to uncover the chemical pathway from reactant...... zeolites for an in-depth structural exploration. The amount of information that can be retrieved using such excellent data is pushed to the limit. Finally, combined diffraction and absorption experiments were performed in situ on copper-loaded chabazite zeolite. Catalytic intermediate species...

  8. Sulfur tolerant zeolite supported platinum catalysts for aromatics hydrogenation

    Energy Technology Data Exchange (ETDEWEB)

    Bergem, Haakon

    1997-12-31

    The increased demand for transportation fuels at the expence of heavier fuel oil has forced the refinery industry to expand their conversion capacity with hydrotreating as one of the key processes. A shift towards more diesel powered vehicles along with tightening fuel regulations demanding cleaner fuels has lead to increasing interest in catalytic processes for the manufacturing of such environmentally acceptable fuels. This provides the motivation for this thesis. Its main objective was to study possible catalysts active for desulfurization, hydrogenation, and ring-opening of aromatics all in the presence of sulfur. A close examination of the physical properties and kinetical behaviour of the chosen catalysts has been performed. A high pressure reactor setup was designed and built for activity measurements. Zeolite supported platinum catalysts were prepared and both the metal and acid functions were characterized utilizing various experimental techniques. Hydrogenation of toluene was used as a model reaction and the effect of sulfur adsorption on the activity and kinetic behaviour of the catalysts was investigated. The catalyst samples showed hydrogenation activities comparable to a commercial Pt/Al2O3 catalyst. There were no clear differences in the effect of the various sulfur compounds studied. Platinum supported on zeolite Y gave considerably more sulfur tolerant catalysts compared to Al2O3 as support. 155 refs., 58 figs., 36 tabs.

  9. Progress on Incorporating Zeolites in Matrimid®5218 Mixed Matrix Membranes towards Gas Separation

    Directory of Open Access Journals (Sweden)

    Roberto Castro-Muñoz

    2018-06-01

    Full Text Available Membranes, as perm-selective barriers, have been widely applied for gas separation applications. Since some time ago, pure polymers have been used mainly for the preparation of membranes, considering different kinds of polymers for such preparation. At this point, polyimides (e.g., Matrimid®5218 are probably one of the most considered polymers for this purpose. However, the limitation on the performance relationship of polymeric membranes has promoted their enhancement through the incorporation of different inorganic materials (e.g., zeolites into their matrix. Therefore, the aim of this work is to provide an overview about the progress of zeolite embedding in Matrimid®5218, aiming at the preparation of mixed matrix membranes for gas separation. Particular attention is paid to the relevant experimental results and current findings. Finally, we describe the prospects and future trends in the field.

  10. Synthesis of zeolite membrane (Y / α-alumina)

    International Nuclear Information System (INIS)

    Araujo, Ana Paula; Silva, Valmir Jose da; Crispin, Alana Carolyne; Rodrigues, Meiry Glaucia F.; Menezes, Romualdo R.

    2009-01-01

    The general aim of this study was to develop materials of the type: Y zeolite (hydrothermal synthesis), ceramic support (forming of powder) and zeolite membrane (rubbing). The preparation of the Y zeolite was conducted in accordance with the hydrothermal synthesis method, the time of crystallization was one day. The ceramic support was prepared by means of the forming of powder technique and subsequently subjected to sintering at a temperature of 1400 deg C/1h. The zeolite membrane (Y/α- alumina) was prepared by secondary growth method (rubbing). These materials were characterized by XRD and SEM. Obtaining Y zeolite could be confirmed by X ray diffractograms. From the images obtained by SEM, it was possible to derive from analysis that the Y zeolite is composed of a homogeneous morphology, where the particles are crowded, with uniform size. The results obtained for the ceramic support (α-alumina) showed that it displays characteristics peaks of aluminum oxide. By using micrographs it was possible to observe a heterogeneous microstructure with a compact form, without cracks upon the layers. According to the XRD, for the method of secondary growth (rubbing), it was observed that the Y zeolite which had been synthesized on the ceramic support displayed a crystalline structure. The micrography of the zeolite membrane (Y/α-alumina) showed the formation of a layer of zeolite on the ceramic support. (author)

  11. Adsorption site of ammonia on copper-exchanged Y-type zeolite under coexisting water vapor. Temperature-programed desorption and infrared adsorption spectra

    Energy Technology Data Exchange (ETDEWEB)

    Kasaoka, S.; Sasaoka, E.; Shiraga, T.; Ono, Y.

    1978-03-01

    Sodium Y zeolites were copper-exchanged with cupric nitrate in water, in aqueous ammonia, and in aqueous ammonia/ammonium chloride, and calcined at 500/sup 0/C. Temperature-programed desorption and IR spectroscopy showed three types of adsorption sites for 0.1-1.0% ammonia gas from nitrogen containing 0-12% water vapor: physisorption, adsorption as tetraamminocopper(II) on copper(II) sites (type 2 site), and adsorption as ammonium ion on hydroxyl sites (type 3 site). Adsorption on type 2 sites occurred only at high ammonia concentration; desorption occurred around 175/sup 0/C. Type 3 sites consisted of Cu(OH)/sup +/ and Al(OH)/sup +/, adsorbed ammonia from low concentrations, and at temperatures above 200/sup 0/C, were probably the active sites for the reduction of nitric oxide by ammonia.

  12. Hydrodeoxygenation and coupling of aqueous phenolics over bifunctional zeolite-supported metal catalysts.

    Science.gov (United States)

    Hong, Do-Young; Miller, Stephen J; Agrawal, Pradeep K; Jones, Christopher W

    2010-02-21

    Pt supported on HY zeolite is successfully used as a bifunctional catalyst for phenol hydrodeoxygenation in a fixed-bed configuration at elevated hydrogen pressures, leading to hydrogenation-hydrogenolysis ring-coupling reactions producing hydrocarbons, some with enhanced molecular weight.

  13. Carbon monoxide hydrogenation over ruthenium zeolites

    Energy Technology Data Exchange (ETDEWEB)

    Jacobs, P.A.; Nijs, H.H.; Verdonck, J.J.; Uytterhoeven, J.B.

    1978-03-01

    Ru zeolites are active and stable methanation catalysts. Under Fischer--Tropsch conditions they show a narrow product distribution. Further work is needed to assign this to a possible effect exerted by the zeolite cages. When the size of the Ru particles enclosed in the zeolite cages is increased, a lower methanation activity is found and a higher amount of C/sub 2/ and C/sub 3/ products are formed under Fischer--Tropsch conditions. This effect has not been reported until now on other supports. The less acidic zeolites act as promoters of the CO hydrogenation: under methanation conditions the activity is increased; under Fischer--Tropsch conditions, the selectivity is shifted toward higher hydrocarbons. This is explained by the particular zeolite property that electron deficient metal agglomerates seem to be formed on the acidic zeolites. With respect to kinetic behavior, relative activity of different metals, influence of reaction temperature on product distribution, the zeolite behaves in the same way a conventional alumina support. 4 figs., 4 tables.

  14. Physicochemical impact of zeolites as the support for photocatalytic hydrogen production using solar-activated TiO2-based nanoparticles

    International Nuclear Information System (INIS)

    Taheri Najafabadi, Amin; Taghipour, Fariborz

    2014-01-01

    Highlights: • Zeolite chemical properties are crucial to photocatalytic hydrogen production. • Basic zeolite, TiO 2 , heteropolyacid and cobalt together are active under visible light. • TiO 2 impregnation on zeolite causes band gap widening and band edges’ anodic shift. • Heteropolyacid enhances the visible light activity of the photocatalyst. • Zeolite’s basicity can overshadow the anodic shift, advancing hydrogen evolution. - Abstract: Silico-aluminates (zeolites) have been recently utilized promisingly as the support for photocatalytic hydrogen production using solar-activated TiO 2 -based nanoparticles. Aside from conventional advantages offered by the supports in photocatalysis, we demonstrate the unique physicochemical impact of zeolites on photocatalytic hydrogen production. Beside zeolites, our synthesized materials comprise titanium dioxide (TiO 2 ) as the semiconductor, cobalt ions as the hydrogen evolution sites, and heteropolyacids (HPAs) as the multifunctional solid acids with significant excitability under visible light. Four classes of zeolites (Na-Y, Na-mordenite, H-Y, and H-beta) with different Si/Al ratios and sodium contents were evaluated. Among the studied photocatalysts, Na-Y and Na-mordenite containing 10 wt% titania emerged as the potential candidates for the hydrogen evolution reaction, with corresponding rates of 250.8 and 187.2 μmol/g h, in comparison to 84.2 μmol/g h for Degussa P25; while these values for H-Y and H-beta were 96.8 and 100.1 μmol/g h, respectively. The higher photocatalytic activity of the first two classes is attributed to the basicity of the zeolite matrix, which is possibly due to the pH dependency of the TiO 2 band edges. The results indicate the importance of controlling the chemical properties of the zeolite as a photocatalyst support through the selection of suitable types. Furthermore, our analyses show that the precise pore size distribution of the zeolite framework rules over accommodating the

  15. Design and fabrication of zeolite macro- and micromembranes

    Science.gov (United States)

    Chau, Lik Hang Joseph

    2001-07-01

    The chemical nature of the support surface influences zeolite nucleation, crystal growth and elm adhesion. It had been demonstrated that chemical modification of support surface can significantly alter the zeolite film and has a good potential for large-scale applications for zeolite membrane production. The incorporation of titanium and vanadium metal ions into the structural framework of MFI zeolite imparts the material with catalytic properties. The effects of silica and metal (i.e., Ti and V) content, template concentration and temperature on the zeolite membrane growth and morphology were investigated. Single-gas permeation experiments were conducted for noble gases (He and Ar), inorganic gases (H2, N2, SF6) and hydrocarbons (methane, n-C4, i-C4) to determine the separation performance of these membranes. Using a new fabrication method based on microelectronic fabrication and zeolite thin film technologies, complex microchannel geometry and network (supported zeolite films. The zeolite micropatterns were stable even after repeated thermal cycling between 303 K and 873 K for prolonged periods of time. This work also demonstrates that zeolites (i.e., Sil-1, ZSM-5 and TS-1) can be employed as catalyst, membrane or structural materials in miniature chemical devices. Traditional semiconductor fabrication technology was employed in micromachining the device architecture. Four strategies for the manufacture of zeolite catalytic microreactors were discussed: zeolite powder coating, uniform zeolite film growth, localized zeolite growth, and etching of zeolite-silicon composite film growth inhibitors. Silicalite-1 was also prepared as free-standing membrane for zeolite membrane microseparators.

  16. Sorption of Cu(II) Ions on Chitosan-Zeolite X Composites: Impact of Gelling and Drying Conditions.

    Science.gov (United States)

    Djelad, Amal; Morsli, Amine; Robitzer, Mike; Bengueddach, Abdelkader; di Renzo, Francesco; Quignard, Françoise

    2016-01-19

    Chitosan-zeolite Na-X composite beads with open porosity and different zeolite contents were prepared by an encapsulation method. Preparation conditions had to be optimised in order to stabilize the zeolite network during the polysaccharide gelling process. Composites and pure reference components were characterized using X-ray diffraction (XRD); scanning electron microscopy (SEM); N₂ adsorption-desorption; and thermogravimetric analysis (TG). Cu(II) sorption was investigated at pH 6. The choice of drying method used for the storage of the adsorbent severely affects the textural properties of the composite and the copper sorption effectiveness. The copper sorption capacity of chitosan hydrogel is about 190 mg·g(-1). More than 70% of this capacity is retained when the polysaccharide is stored as an aerogel after supercrititcal CO₂ drying, but nearly 90% of the capacity is lost after evaporative drying to a xerogel. Textural data and Cu(II) sorption data indicate that the properties of the zeolite-polysaccharide composites are not just the sum of the properties of the individual components. Whereas a chitosan coating impairs the accessibility of the microporosity of the zeolite; the presence of the zeolite improves the stability of the dispersion of chitosan upon supercritical drying and increases the affinity of the composites for Cu(II) cations. Chitosan-zeolite aerogels present Cu(II) sorption properties.

  17. Method of producing zeolite encapsulated nanoparticles

    DEFF Research Database (Denmark)

    2015-01-01

    The invention therefore relates to a method for producing zeolite, zeolite-like or zeotype encapsulated metal nanoparticles, the method comprises the steps of: 1) Adding one or more metal precursors to a silica or alumina source; 2) Reducing the one or more metal precursors to form metal...... nanoparticles on the surface of the silica or alumina source; 3) Passing a gaseous hydrocarbon, alkyl alcohol or alkyl ether over the silica or alumina supported metal nanoparticles to form a carbon template coated zeolite, zeolite-like or zeotype precursor composition; 4a) Adding a structure directing agent...... to the carbon template coated zeolite, zeolite-like or zeotype precursor composition thereby creating a zeolite, zeolite-like or zeotype gel composition; 4b) Crystallising the zeolite, zeolite-like or zeotype gel composition by subjecting said composition to a hydrothermal treatment; 5) Removing the carbon...

  18. Method for producing zeolites and zeotypes

    DEFF Research Database (Denmark)

    2015-01-01

    The invention relates to a method for producing zeolite, zeolite-like or zeotype particles comprising the steps of: 1 ) Adding one or more metal precursors to a silica or alumina source; 2) Reducing the one or more metal precursors to form metal nanoparticles on the surface of the silica or alumina...... source; 3) Passing a gaseous hydrocarbon, alkyl alcohol or alkyl ether over the silica or alumina supported metal nanoparticle to form a carbon template coated zeolite, zeolite-like or zeotype precursor composition; 4a) Adding a structure directing agent to the carbon template coated zeolite, zeolite......-like or zeotype precursor composition thereby creating a zeolite, zeolite-like or zeotype gel composition; 4b) Crystallising the zeolite, zeolite-like or zeotype gel composition by subjecting said composition to a hydrothermal treatment; 5) Removing the carbon template and structure directing agent and isolating...

  19. Characterization of NaA Zeolite Oxygen Permeable Membrane on TiO2/α-Al2O3 Composite Support

    Directory of Open Access Journals (Sweden)

    Zhu Mengfu

    2016-01-01

    Full Text Available The NaA zeolite membrane was synthesized on the surface of TiO2/α-Al2O3 composite support with TiO2 as modifier of α-Al2O3 porous tubular ceramic membrane support by crystallization method. The structure characterization indicated that the TiO2 of the support surface could effectively improve the surface properties of the support. It didn’t affect the crystallization of NaA synthesis liquid and synthesis process of NaA zeolite membrane. There were no obvious defects between the crystal particles with size of approximate 6μm. The perfect and complete membrane with thickness of approximate 15μm combined closely with support to connection together by TiO2 modified. The oxygen permeability of the membrane on TiO2/α-Al2O3 composite support improves of 47% compared with that of α-Al2O3 support. So the process of TiO2 modifying the surface of α-Al2O3 support should increase the oxygen permeability of the NaA zeolite membrane.

  20. Synthesis and characterization of 12-phosphotungstic acid supported on BEA zeolite

    Energy Technology Data Exchange (ETDEWEB)

    Jović, A.; Bajuk-Bogdanović, D.; Nedić Vasiljević, B. [Faculty of Physical Chemistry, University of Belgrade, Studentski trg 12-16, 11000 Belgrade (Serbia); Milojević-Rakić, M., E-mail: maja@ffh.bg.ac.rs [Faculty of Physical Chemistry, University of Belgrade, Studentski trg 12-16, 11000 Belgrade (Serbia); Krajišnik, D. [Department of Pharmaceutical Technology and Cosmetology, University of Belgrade-Faculty of Pharmacy, Vojvode Stepe 450, 11000 Belgrade (Serbia); Dondur, V. [Faculty of Physical Chemistry, University of Belgrade, Studentski trg 12-16, 11000 Belgrade (Serbia); Popa, A. [Institute of Chemistry Timisoara, Bl. Mihai Viteazul 24, 300223 Timisoara (Romania); Uskoković-Marković, S. [Department of Analytical Chemistry, University of Belgrade-Faculty of Pharmacy, Vojvode Stepe 450, 11000 Belgrade (Serbia); Holclajtner-Antunović, I. [Faculty of Physical Chemistry, University of Belgrade, Studentski trg 12-16, 11000 Belgrade (Serbia)

    2017-01-15

    An optimized synthetic route for obtaining heteropoly acid (HPA) species supported on BEA zeolite was applied, and different samples, comprising 20 to 50 wt% of 12-phosphotungstic acid (HPW) were prepared. The as-synthesized supported HPW were subjected to different post-synthesis routes, which involved calcination and ultrasound treatment. Characterization of these materials was performed by means of Scanning Electron Microscopy, zeta potential measurements, Infrared Spectroscopy and X-ray Powder Diffraction analysis. Results suggest strong interaction of HPW with the support and revealed that ultrasound treatment resulted in better dispersion of active phase and thus homogeneous morphology of the samples. The zeta potential was found to be dependent on the preparation procedure and HPW content in these materials, while higher HPW loadings induced its agglomeration. Catalytic activity of the synthesized materials was investigated in an ethanol dehydration reaction, where lower HPW loadings induced higher ethanol conversion. Acid sites distribution and accessibility for ethanol molecules were found to be more essential for catalytic activity than HPW loadings, i.e., amount of active sites present in these hybrid materials. - Highlights: • An optimized route for supporting heteropoly acid on beta zeolite is applied. • Ultrasound treatment of the composites gives dispersed morphology. • Lower heteropoly acid amount induces higher conversion in ethanol dehydration. • Acid sites distribution and accessibility for ethanol are essential for catalytic activity.

  1. Synthesis and characterization of 12-phosphotungstic acid supported on BEA zeolite

    International Nuclear Information System (INIS)

    Jović, A.; Bajuk-Bogdanović, D.; Nedić Vasiljević, B.; Milojević-Rakić, M.; Krajišnik, D.; Dondur, V.; Popa, A.; Uskoković-Marković, S.; Holclajtner-Antunović, I.

    2017-01-01

    An optimized synthetic route for obtaining heteropoly acid (HPA) species supported on BEA zeolite was applied, and different samples, comprising 20 to 50 wt% of 12-phosphotungstic acid (HPW) were prepared. The as-synthesized supported HPW were subjected to different post-synthesis routes, which involved calcination and ultrasound treatment. Characterization of these materials was performed by means of Scanning Electron Microscopy, zeta potential measurements, Infrared Spectroscopy and X-ray Powder Diffraction analysis. Results suggest strong interaction of HPW with the support and revealed that ultrasound treatment resulted in better dispersion of active phase and thus homogeneous morphology of the samples. The zeta potential was found to be dependent on the preparation procedure and HPW content in these materials, while higher HPW loadings induced its agglomeration. Catalytic activity of the synthesized materials was investigated in an ethanol dehydration reaction, where lower HPW loadings induced higher ethanol conversion. Acid sites distribution and accessibility for ethanol molecules were found to be more essential for catalytic activity than HPW loadings, i.e., amount of active sites present in these hybrid materials. - Highlights: • An optimized route for supporting heteropoly acid on beta zeolite is applied. • Ultrasound treatment of the composites gives dispersed morphology. • Lower heteropoly acid amount induces higher conversion in ethanol dehydration. • Acid sites distribution and accessibility for ethanol are essential for catalytic activity.

  2. EXAFS study of Mo2N and Mo nitrides supported on zeolites

    International Nuclear Information System (INIS)

    Liu Zhenlin; Meng Ming; Fu Yilu; Jiang Ming; Hu Tiandou; Xie Yaning; Liu Tao

    2002-01-01

    In the present study, the reaction is applied to prepare molybdenum nitrides with high surface area, and zeolites are used as supports. The EXAFS of the Mo K-absorption edge is measured and the change of coordination environment of Mo atoms before and after the nitridation is revealed

  3. Recent progress in the direct synthesis of hierarchical zeolites: synthetic strategies and characterization methods

    KAUST Repository

    Liu, Zhaohui; Hua, Yingjie; Wang, Jianjian; Dong, Xinglong; Tian, Qiwei; Han, Yu

    2017-01-01

    Hierarchically structured zeolites combine the merits of microporous zeolites and mesoporous materials to offer enhanced molecular diffusion and mass transfer without compromising the inherent catalytic activities and selectivity of zeolites

  4. Application of zeolite-based catalyst to hydrocracking of coal-derived liquids

    Energy Technology Data Exchange (ETDEWEB)

    Shimada, H.; Sato, T.; Yoshimura, Y.; Hinata, A.; Yoshitomi, S.; Castillo Mares, A.; Nishijima, A. (National Chemical Laboratory for Industry, Tsukuba (Japan))

    1990-06-01

    Y-zeolite supported catalysts were applied to the hydrocracking of coal-derived liquids. By the introduction of two-stage upgrading consisting of hydrotreating and hydrocracking, Wandoan coal-derived middle distillate was hydrocracked over Ni-Mo/Y-zeolite, producing a high gasoline fraction yield. Zeolite supported catalysts gave little hydrocracked compounds in the hydroprocessing of coal-derived heavy oils, even after hydrotreatment. The reaction inhibitors which seriously poison the active sites of zeolites were found to be small nitrogen-containing molecules. In the hydroprocessing of coal-derived heavy oils, zeolite supported catalysts were inferior to alumina supported catalysts. This is due to the high hydrocracking but low hydrogenation activity of zeolite supported catalysts. 22 refs., 5 figs., 11 tabs.

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

    Science.gov (United States)

    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.

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

    Science.gov (United States)

    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.

  7. for zeolite coating

    Directory of Open Access Journals (Sweden)

    Carlos Renato Rambo

    2006-01-01

    Full Text Available Biotemplating is the processing of microcellular ceramics by reproduction of natural morphologies, where the microstructural features of the biotemplate are maintained in the biomorphic ceramic. Different biotemplates with distinct pore anatomies were used to produce biomorphic supports for the zeolite coating: wood, cardboard, sea-sponge and sisal. The biomorphic ceramics were produced by distinguished processing routes: Al-gas infiltration-reaction, liquid-metal infiltration, dip-coating and sol-gel synthesis, in order to produce nitrides, carbides and oxides, depending on the processing conditions. The zeolite coating was performed by hydrothermal growth of MFI-type (Silicalite-1 and ZSM-5 zeolite crystals onto the internal pore walls of the biomorphic templates. The final biomorphic ceramic-zeolite composites were physically characterized, evaluated in terms of their gas adsorption capabilities and correlated to their microstructure and specific pore anatomy. The combination of the properties of the biomorphic ceramics with the adsorption properties of zeolites results in materials with distinct properties as potential candidates for adsorption and catalytic applications due to their characteristic porosity, molecular sieving capabilities and high thermo-mechanical strength.

  8. Catalytic reduction of NO{sub x} in gasoline engine exhaust over copper- and nickel-exchanged X-zeolite catalysts

    Energy Technology Data Exchange (ETDEWEB)

    Bhattacharyya, S. [Indian Inst. of Technology, Kharagpur (India). Dept. of Mechanical Engineering; Das, R.K. [Indian School of Mines, Dhanbad (India). Dept. of Engineering and Mining Machinery

    2001-10-11

    Catalytic removal of NO{sub x} in engine exhaust gases can be accomplished by non-selective reduction, selective reduction and decomposition. Noble metals are extensively used for non-selective reduction of NO{sub x} and up to 90% of engine NO{sub x} emissions can be reduced in a stoichiometric exhaust. This requirement of having the stoichiometric fuel-air ratio acts against efficiency improvement of engines. Selective NO{sub x} reduction in the presence of different reductants such as, NH{sub 3}, urea or hydrocarbons, requires close control of the amount of reductant being injected which otherwise may be emitted as a pollutant. Catalytic decomposition is the best option for NO{sub x} removal. Nevertheless, catalysts which are durable, economic and active for NO{sub x} reduction at normal engine exhaust temperature ranges are still being investigated. Three catalysts based on X-zeolite have been developed by exchanging the Na+ ion with copper, nickel and copper-nickel metal ions and applied to the exhaust of a stationary gasoline engine to explore their potential for catalytic reduction of NO{sub x} under a wide range of engine and exhaust conditions. Some encouraging results have been obtained. The catalyst Cu-X exhibits much better NO{sub x} reduction performance at any temperature in comparison to Cu-Ni-X and Ni-X; while Cu-Ni-X catalyst exhibits slightly better performance than Ni-X catalyst. Maximum NO{sub x} efficiency achieved with Cu-X catalyst is 59.2% at a space velocity (sv) of 31 000 h{sup -1}; while for Cu-Ni-X and Ni-X catalysts the equivalent numbers are 60.4% and 56% respectively at a sv of 22 000 h{sup -1}. Unlike noble metals, the doped X-zeolite catalysts exhibit significant NO{sub x} reduction capability for a wide range of air/fuel ratio and with a slower rate of decline as well with increase in air/fuel ratio. (author)

  9. Catalytic upgrading of oleic acid into biofuel using Mo modified zeolite supported Ni oxalate catalyst functionalized with fluoride ion

    International Nuclear Information System (INIS)

    Ayodele, O.B.; Abbas, Hazzim F.; Daud, Wan Mohd Ashri Wan

    2014-01-01

    Highlights: • Modification of zeolite with freshly prepared molybdenum oxalate. • Functionalization of Ni oxalate with HF and incorporation into Mo modified zeolite. • Characterization of synthesized Mo modified zeolite supported Ni oxalate catalyst. • Deoxygenation of oleic acid with the synthesized zeolite supported catalyst. • Reusability study on the synthesized zeolite supported catalyst. - Abstract: In this study, fluoride ion functionalized nickel oxalate supported on molybdenum modified zeolite (NiMoFOx/Zeol) catalyst was synthesized, characterized and tested on the hydrodeoxygenation (HDO) of oleic acid (OA) into paraffinic fuel. The NiMoFOx/Zeol characterization results confirmed the presence of both Ni and Mo as well as the formation of NiMoO 4 which is a highly HDO reactive specie at 2θ value of 43.6° according to the XRD result. NiMoFOx/Zeol also showed loss in crystallinity and reduction in the average particle size leading to increase in the pore volume and specific surface area due to the combined effects of fluoride ion presence, oxalic acid functionalization and calcination. The effect of temperature, pressure and NiMoFOx/Zeol loading studied showed that initial increase in their values increased the yield of the target fractions until some points where reduction was observed. The best observed experimental conditions to hydrodeoxygenate 40 g (∼45 mL) of OA into 75% n-C 18 and 23% i-C 18 were 360 °C, 30 mg NiMoFOx/Zeol loading and 20 bar using 100 mL H 2 /min. The presence of i-C 18 was due to the functionalization of the catalyst with fluoride ion. The catalyst reusability result displayed excellent qualities with marginal loss of only 2% in activity after third reuse due to the improved synthesis protocol that employed organometallic precursor. The results are strongly encouraging for further studies toward industrialization of HDO process

  10. Obtaining of supports macro and micro nutrients with base in zeolites mexicans

    International Nuclear Information System (INIS)

    Cordova H, A.; Islas M, M.; Bascunan S, C.; Martines G, M.; Nikolaev N, S.

    2001-01-01

    Study the effect of application of the zeolites modified by the ionico interchange with fertilizers (NPK), N-p in the production of tomatos. The cultive of tomatos was made in lands of the Benemerita Autonoma Universidad de Puebla, Mexico, taking equal quadrants with the following ground treatments: 1) zeolite interchanged with fertilizers, 2) zeolite interchanged with a solution that contained only N-p, 3) natural zeolite without ionica modification and a quadrant witness represented by the ground without treatment. The collected data show an increase in the harvest of tomatos, as well as the retention of the decomposition of the harvested tomatos. In addition, it determinated that the optimal concentrations in the case of the zeolite dealt with 3% of fertilizer NPK are: 0,91% of potassium and 0.61% of nitrogen. These results allow to suggest the use of zeolites modified by ionico interchange in agriculture to elevate the level of the harvests of the tomato [es

  11. Evaluation of photocatalytic activities of supported catalysts on NaX zeolite or activated charcoal

    Energy Technology Data Exchange (ETDEWEB)

    Brites-Nóbrega, Fernanda F. de [Chemical Engineering Department, Universidade Estadual de Maringá (UEM), Av. Colombo, 5790, CEP 87020-900 Maringá, PR (Brazil); Sanitary and Environmental Engineering Department, Universidade Federal de Minas Gerais (UFMG), Av. Antônio Carlos, 6627, Campus Pampulha, Belo Horizonte, MG (Brazil); Polo, Aldino N.B.; Benedetti, Angélica M. [Chemical Engineering Department, Universidade Estadual do Oeste do Paraná (UNIOESTE), Rua da Faculdade, 645, CEP 85903-000 Toledo, PR (Brazil); Leão, Mônica M.D. [Sanitary and Environmental Engineering Department, Universidade Federal de Minas Gerais (UFMG), Av. Antônio Carlos, 6627, Campus Pampulha, Belo Horizonte, MG (Brazil); Slusarski-Santana, Veronice, E-mail: veronice.santana@unioeste.br [Chemical Engineering Department, Universidade Estadual do Oeste do Paraná (UNIOESTE), Rua da Faculdade, 645, CEP 85903-000 Toledo, PR (Brazil); Fernandes-Machado, Nádia R.C. [Chemical Engineering Department, Universidade Estadual de Maringá (UEM), Av. Colombo, 5790, CEP 87020-900 Maringá, PR (Brazil)

    2013-12-15

    Highlights: • The synergic effect between ZnO and NaX was positive, which increased its activity. • The best results were obtained at pH 3 and 9 with ZnO/NaX and at pH 3 with Nb{sub 2}O{sub 5}/AC. • High degradation and considerable mineralization were attained with 10% ZnO/NaX. • ZnO and Nb{sub 2}O{sub 5} supported on NaX and AC are promising alternatives as photocatalysts. -- Abstract: This study aimed to evaluate the photocatalytic activity of ZnO and Nb{sub 2}O{sub 5} catalysts, both supported on NaX zeolite and activated charcoal (AC). The synergistic effect between oxide and support and the influence of solution pH (3, 7 and 9) on photocatalytic degradation of reactive blue 5G (C.I. 222) were analyzed. The catalysts Nb{sub 2}O{sub 5}/NaX, Nb{sub 2}O{sub 5}/AC and ZnO/NaX, ZnO/AC with 5 and 10% (wt%) were prepared by wet impregnation. The results showed that the catalysts exhibit quite different structural and textural properties. The synergic effect between ZnO and NaX support was higher than that with the activated charcoal, showing that these catalysts were more efficient. The most photoactive catalyst was 10% ZnO/NaX which showed 100% discoloration of the dye solution at pH 3, 7 and 9 after 0.5, 5 and 2 h of irradiation, respectively. The hydrolytic nature of zeolite favored the formation of surface hydroxyl radicals, which increased the activity of the photocatalyst. Thus, catalysts supported on NaX zeolite are promising for use in photocatalysis.

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

    Science.gov (United States)

    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.

  13. Biotemplating of Luffa cylindrica sponges to self-supporting hierarchical zeolite macrostructures for bio-inspired structured catalytic reactors

    International Nuclear Information System (INIS)

    Zampieri, Alessandro; Mabande, Godwin T.P.; Selvam, Thangaraj; Schwieger, Wilhelm; Rudolph, Alexander; Hermann, Ralph; Sieber, Heino; Greil, Peter

    2006-01-01

    Biomorphic self-supporting MFI-type zeolite frameworks with hierarchical porosity and complex architecture were prepared using a 2-step (in-situ seeding and secondary crystal growth) hydrothermal synthesis in the presence of a biological template (Luffa sponge), employed as a macroscale sacrificial structure builder. The bio-inspired zeolitic replica inherited the complex spongy morphology and the intricate open-porous architecture of the biotemplate. Moreover, it exhibited reasonable mechanical stability in order to study the applicability of the biomorphic catalyst in a technical catalytic process. A bio-inspired catalytic reactor utilising the self-supporting ZSM-5 scaffold in monolithic configuration was developed in order to test the catalytic performance of the material

  14. Catalytic reduction of nitric oxide with ammonia over transition metal ion-exchanged Y zeolites

    Energy Technology Data Exchange (ETDEWEB)

    Sciyama, T; Arakawa, T; Matsuda, T; Yamazoe, N; Takita, Y

    1975-01-01

    The catalytic reduction of nitric oxide with ammonia was studied over transition metal ion-exchanged Y zeolite (Me-Y) catalysts. The reaction products are nitrogen, nitrous oxide, and water in all cases. Selectivities to N/sub 2/ are 60 to 80% on all the cation exchanged zeolite catalysts exhibiting a relatively minor variation with the cationic species exchanged. The copper (II)-Y catalyst exhibits low temperature activity and has an unusual catalytic activity-temperature profile with a maximum at 120/sup 0/C. The catalytic activity is enhanced considerably when a second cation, especially cobalt (II) or iron (III) is coexchanged together with Cu (II) in Y zeolite.

  15. Availability of zeolite as an eliminant for the incorporated radionuclides, (3)

    International Nuclear Information System (INIS)

    Sato, Itaru; Matsusaka, Naonori; Kobayashi, Haruo; Nishimura, Yoshikazu.

    1994-01-01

    Zeolite is an inorganic ion-exchanger that is widely used in chemistry, livestock and industry. The authors have tried to apply it to an eliminant for the incorporated radionuclides. In this study, several experiments in vitro and in vivo were carried out to evaluate the effectiveness of zeolite (A-3) in eliminating the incorporated 137 Cs from the body. Zeolite could adsorb 2.2 mmol of cesium ions per one gram of zeolite in cesium chloride solution. This value was only 44% of its ion-exchange capacity but it completely adsorbed 137 Cs within that limit. Coexistence of magnesium, calcium, manganese, cobalt and zinc ions hardly interfered with the adsorption of 137 Cs, but sodium, potassium and copper ions hindered the adsorption in proportion to their concentration. Therefore, sodium and potassium ions may be principal factors inhibiting the adsorption of 137 Cs in the intestinal tract. Biological half-life of 137 Cs was about 5.5 days in control mice. This half-life was significantly reduced to 5.2, 4.5 and 3.9 days by feeding the diet with 1%, 3% and 10% of zeolite, respectively. These results suggest the effectiveness of zeolite in eliminating the 137 Cs from contaminated persons. (author)

  16. Mechanism of Catalytic Behavior and Structure of Active Centers in CuY Zeolite

    OpenAIRE

    Tanabe, Shuji; Matsumoto, Hiroshige

    1990-01-01

    The experimental and theoretical basis for the activated coppere xchanged Y zeolite system have been studied by the observation and analysis in the electronspin resonanace (ESR) , infrared (IR) and extended X-ray absorption fine structure (EXAFS) spectroscopies.

  17. Light alkane (mixed feed selective dehydrogenation using bi-metallic zeolite supported catalyst

    Directory of Open Access Journals (Sweden)

    Zeeshan Nawaz

    2009-12-01

    Full Text Available Light alkanes are the important intermediates of many refinery processes and their catalytic dehydrogenation gives corresponding alkenes. The aim behind this experimentation is to investigate reaction behavior of mixed alkanes during direct catalytic dehydrogenation and emphasis has been given to enhance propene. Bi-metallic zeolite supported catalyst Pt-Sn/ZSM-5 was prepared by sequentional impregnation method and characterized by BET, EDS and XRD. Direct dehydrogenation reaction is highly endothermic and its conversion is thermodynamically limited. Results showed that the increase in temperature increases the conversion to some extent but there is no overall effect on selectivity of propene. Increase in time-on-stream (TOS remarkably improves propene selectivity at the expense of lower conversion. The performances of bi-metallic zeolite based catalyst largely affected by coke deposition. The presence of butane and ethane adversely affected propane conversion. Optimum propene selectivity is about 48 %, obtained at 600 oC and time-on-stream 10 h.

  18. Gold-copper bimetallic nanoparticles supported on nano P zeolite modified carbon paste electrode as an efficient electrocatalyst and sensitive sensor for determination of hydrazine.

    Science.gov (United States)

    Amiripour, Fatemeh; Azizi, Seyed Naser; Ghasemi, Shahram

    2018-06-01

    In this report, a facile, efficient and low cost electrochemical sensor based on bimetallic Au-Cu nanoparticles supported on P nanozeolite modified carbon paste electrode (Au-Cu/NPZ/CPE) was constructed and its efficiency for determination of hydrazine in trace level was studied. For this purpose, agro waste material, stem sweep ash (SSA) was employed as the starting material (silica source) for the synthesis of nano P zeolite (NPZ). After characterization of the synthesized NPZ by analytical instruments (scanning electronic microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD) and Fourier transform infrared (FT-IR) spectroscopy), construction of Au-Cu/NPZ/CPE was performed by three steps procedure involving preparation of nano P zeolite modified carbon paste electrode (NPZ/CPE), introducing Cu +2 ions into nano zeolite structure by ion exchange and electrochemical reduction of Cu +2 ions upon applying constant potential. This procedure is followed by partial replacement of Cu by Au due to galvanic replacement reaction (GRR). The electrochemical properties of hydrazine at the surface of Au-Cu/NPZ/CPE was evaluated using cyclic voltammetry (CV), amperometry, and chronoamperometry methods in 0.1 M phosphate buffer solution (PBS). It was found that the prepared sensor has higher electrocatalytic activity at a relatively lower potential compared to other modified electrodes including Au/NPZ/CPE, Cu/NPZ/CPE, Au-Cu/CPE and etc. Moreover, the proposed electrochemical sensor presented the favorable analytical properties for determination of hydrazine such as low detection limit (0.04 µM), rapid response time (3 s), wide linear range (0.01-150 mM), and high sensitivity (99.53 µA mM -1 ) that are related to the synergic effect of bimetallic of Au-Cu, porous structure and enough surface area of NPZ. In addition, capability of Au-Cu/NPZ/CPE sensor was successfully tested in real samples with good accuracy and precision. Copyright

  19. Preparation of Highly Dispersed Copper Particles in Zeolite

    OpenAIRE

    Tanabe, Shuji; Matsumoto, Hiroshige

    1986-01-01

    Temperature programmed reduction and desorption techniques have been used to investigate the reduction process of CuY. The reduction of Cu^2+ ions in zeolite with H_2 occurs via a two-step mechanism in which Cu^+ is first formed and then reduced to metal. In the first step of reduction NH_3 was used as the reducing agent instead of H_2. Cu particles in the reduced CuY with NH_3 pretreatment were uniformly dispersed compared with those of CuY without one. The average particle size of Cu metal ...

  20. Study of catalysts prepared on the basis of synthetic zeolite of A-type in the reaction of oxidation of isopropyl alcohol

    International Nuclear Information System (INIS)

    Aliev, A.M; Matiev, K.I; Mirgashimov, F.M; Kuliev, F.D; Mejidov, N.J

    2011-01-01

    Full text: Partial oxidation of isopropyl alcohol into acetone at the zeolite of A-type modified by ions copper and palladium at the temperature interval 150-230 degree C, of volume velocity 2400 H - 1 under different ratio alcohol-oxygen-helium at atmoshpheric pressure has been studied. It has been established that the conversion of isopropyl alcohol on zeolites CuPdNaA and CuPdCaA is noticable however selective by acetone alcohol, modofoed zeolites, acetone

  1. Support Functionalization To Retard Ostwald Ripening in Copper Methanol Synthesis Catalysts

    NARCIS (Netherlands)

    van den Berg, Roy; Parmentier, Tanja E.; Elkjaer, Christian F.; Gommes, Cedric J.; Sehested, Jens; Helveg, Stig; de Jongh, Petra E.; de Jong, Krijn P.

    A main reason for catalyst deactivation in supported catalysts for methanol synthesis is copper particle growth. We have functionalized the support surface in order to suppress the formation and/or transport of mobile copper species and thereby catalyst deactivation. A Stober silica support was

  2. Processing of radioactive waste solution with zeolites. I. Thermal transformation of Na, Cs and Sr type zeolites

    Energy Technology Data Exchange (ETDEWEB)

    Kanno, T; Mimura, H; Kitamura, T [Tohoku Univ., Sendai (Japan). Research Inst. of Mineral Dressing and Metallurgy

    1976-08-01

    Thermal transformation of Na, Cs and Sr type zeolites were studied by means of differential thermal analysis (DTA), thermogravimetric analysis (TGA) and X-ray powder diffraction. Synthetic zeolites A, X and Y, synthetic mordenite (Zeolon) and natural mordenite were used in this study. Na type zeolites of A and X recrystallized to Nepheline (NaAlSiO/sub 4/) above 1,000/sup 0/C, but the structures of zeolite Y and mordenite collapsed above about 900/sup 0/C and did not recrystallize until 1,200/sup 0/C. Cs type zeolites of A and X recrystallized to pollucite (CsAlSi/sub 2/O/sub 6/) above 1,000/sup 0/C and Cs type of zeolite Y recrystallized to it above 1,100/sup 0/C, but the structure of mordenite collapsed above 1,000/sup 0/C and did not recrystallize until 1,200/sup 0/C. On Sr type zeolites, zeolite A and X recrystallized to strontium aluminosilicate (SrAl/sub 2/Si/sub 2/O/sub 8/) above 1,100/sup 0/C and zeolite Y recrystallized to it above 1,200/sup 0/C, but the structure of mordenite collapsed above 1,000/sup 0/C. The results described above were supported by microscopic observation and the measurement of density. If this solidifications by calcination of zeolites are further studied, new informations concerning the fixation of Cs and Sr will be obtained.

  3. Mechanism of nitric acid generation on Ag-X Zeolite

    International Nuclear Information System (INIS)

    Kanazawa, T.; Kishimoto, T.; Haseba, S.; Mitoh, Y.; Itoh, S.; Nakai, I.

    1983-01-01

    When Ag-X Zeolite is used for the removal of iodine from the off gas streams of nuclear facilities, it is possible that nitric acid is formed on Ag-X Zeolite from co-existing nitrogen dioxide and water vapor. If nitric acid is formed on the surface of Ag-X zeolite, Ag-X zeolite is damaged and is not able to operate for a long time. When Ag-X zeolite is used in NO 2 -O 2 -H 2 O mixture, the nitric acid generation reaction is varied, depending upon the reaction temperature, and concentration of NO 2 and H 2 O. At a temperature of more than 40 deg. C, however, only the surface reaction will be progressed on the zeolite surface. The generation of nitric acid solution on the zeolite can be forecasted through the relationship between the concentration of nitric acid solution, equilibrium vapor pressure of H 2 O, and equilibrium vapor pressure of HNO 3 . Concerning the surface reaction caused on the zeolite, the adsorption water reacts on NO 2 , and the resulting HNO 3 is adsorbed firmly by the zeolite, which is thought to interfere with the surface reaction for generation of the HNO 3 . When the adsorption bed is long, the time required for adsorbed HNO 3 to saturate is increased in proportion to the bed length

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

    International Nuclear Information System (INIS)

    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

  5. Mordenite - Type Zeolite SCR Catalysts with Iron or Copper

    DEFF Research Database (Denmark)

    2012-01-01

    Cu/mordenite catalysts were found to be highly active for the SCR of NO with NH3 and exhibited high resistance to alkali poisoning. Redox and acidic properties of Cu/mordenite were well preserved after poisoning with potassium unlike that of vanadium catalysts. Fe-mordenite catalysts also reveale...... to be essential requirements for the high alkali resistance. Mordenite-type zeolite based catalysts could therefore be attractive alternatives to conventional SCR catalysts for biomass fired power plant flue gas treatment....

  6. Zeolitic materials with hierarchical porous structures.

    Science.gov (United States)

    Lopez-Orozco, Sofia; Inayat, Amer; Schwab, Andreas; Selvam, Thangaraj; Schwieger, Wilhelm

    2011-06-17

    During the past several years, different kinds of hierarchical structured zeolitic materials have been synthesized due to their highly attractive properties, such as superior mass/heat transfer characteristics, lower restriction of the diffusion of reactants in the mesopores, and low pressure drop. Our contribution provides general information regarding types and preparation methods of hierarchical zeolitic materials and their relative advantages and disadvantages. Thereafter, recent advances in the preparation and characterization of hierarchical zeolitic structures within the crystallites by post-synthetic treatment methods, such as dealumination or desilication; and structured devices by in situ and ex situ zeolite coatings on open-cellular ceramic foams as (non-reactive as well as reactive) supports are highlighted. Specific advantages of using hierarchical zeolitic catalysts/structures in selected catalytic reactions, such as benzene to phenol (BTOP) and methanol to olefins (MTO) are presented. Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  7. Zeolite-zeolite composite composed of Y zeolite and single-crystal-like ZSM-5 zeolite: Fabricated by a process like “big fish swallowing little one”

    Energy Technology Data Exchange (ETDEWEB)

    Pan, Meng; Li, Peng [Research Centre of Energy Chemical & Catalytic Technology, Taiyuan University of Technology, Taiyuan 030024 (China); Zheng, Jiajun, E-mail: zhengjiajun@tyut.edu.cn [Research Centre of Energy Chemical & Catalytic Technology, Taiyuan University of Technology, Taiyuan 030024 (China); Liu, Yujian [SINOPEC Research Institute of Petroleum Processing, Beijing, 100083 (China); Kong, Qinglan [Research Centre of Energy Chemical & Catalytic Technology, Taiyuan University of Technology, Taiyuan 030024 (China); Tian, Huiping [SINOPEC Research Institute of Petroleum Processing, Beijing, 100083 (China); Li, Ruifeng, E-mail: rfli@tyut.edu.cn [Research Centre of Energy Chemical & Catalytic Technology, Taiyuan University of Technology, Taiyuan 030024 (China)

    2017-06-15

    Zeolite-zeolite composite composed of Y and ZSM-5 zeolite was prepared using depolymerized Y as partial nutrients for the growth of ZSM-5. The as-synthesized samples were characterized by X-ray powder diffraction (XRD), FT-IR, scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), transmission electron microscopy (TEM), N{sub 2} adsorption-desorption measurement and Thermogravimetric analysis (TG). Chemical equilibrium at the solution-crystal interface was changed because of the partially depolymerized Y zeolite, the conditions necessary for the growth of ZSM-5 were therefore obtained. ZSM-5 zeolite crystals nucleated and grew on the interface, and Y zeolite crystals were then gradually swallowed by the growing single-crystal-like ZSM-5. - Graphical abstract: Y zeolite crystals in the hydrothermal system were partially depolymerized and an ambience in favor of the formation of ZSM-5 was formed, and ZSM-5 zeolite crystals nucleated and grew up on the external surfaces of Y zeolite crystals. As a consequence, Y zeolite crystals were swallowed by single-crystal-like ZSM-5. - Highlights: • Zeolite composite is composed by Y zeolite and single-crystal-like ZSM-5. • A composite material formed by a process like “big fish swallowing little one”. • Ratio of two zeolites in the as-synthesized sample can be adjusted.

  8. Progress in the understanding of the long-term corrosion behaviour of copper canisters

    Science.gov (United States)

    King, Fraser; Lilja, Christina; Vähänen, Marjut

    2013-07-01

    Copper has been proposed as a canister material for the disposal of spent nuclear fuel in a deep geologic repository in a number of countries worldwide. Since it was first proposed for this purpose in 1978, a significant number of studies have been performed to assess the corrosion performance of copper under repository conditions. These studies are critically reviewed and the suitability of copper as a canister material for nuclear waste is re-assessed. Over the past 30-35 years there has been considerable progress in our understanding of the expected corrosion behaviour of copper canisters. Crucial to this progress has been the improvement in the understanding of the nature of the repository environment and how it will evolve over time. With this improved understanding, it has been possible to predict the evolution of the corrosion behaviour from the initial period of warm, aerobic conditions in the repository to the long-term phase of cool, anoxic conditions dominated by the presence of sulphide. An historical review of the treatment of the corrosion behaviour of copper canisters is presented, from the initial corrosion assessment in 1978, through a major review of the corrosion behaviour in 2001, through to the current level of understanding based on the results of on-going studies. Compared with the initial corrosion assessment, there has been considerable progress in the treatment of localised corrosion, stress corrosion cracking, and microbiologically influenced corrosion of the canisters. Progress in the mechanistic modelling of the evolution of the corrosion behaviour of the canister is also reviewed, as is the continuing debate about the thermodynamic stability of copper in pure water. The overall conclusion of this critical review is that copper is a suitable material for the disposal of spent nuclear fuel and offers the prospect of containment of the waste for an extended period of time. The corrosion behaviour is influenced by the presence of the

  9. INTERKALASI XILENOL ORANGE PADA ZEOLIT ALAM LAMPUNG SEBAGAI ELEKTRODA ZEOLIT TERMODIFIKASI

    Directory of Open Access Journals (Sweden)

    Fitriyah Fitriyah

    2016-07-01

    Full Text Available Zeolit terbagi menjadi zeolit alam dan zeolit sintesis, kapasitas adsorpsi zeolit alam umumnya lebih rendah daripada zeolit sintesis, sehingga untuk meningkatkan kapasitas adsorpsinya, karakter permukaan zeolit alam perlu diubah dengan melakukan proses modifikasi permukaan melalui berbagai metode, salah satunya dengan metode interkalasi. Tujuan penelitian ini yaitu menginterkalasi zat warna xilenol orange ke dalam zeolit alam Lampung dan mengaplikasikannya sebagai elektroda zeolit termodifikasi. Melalui proses interkalasi diharapkan dapat meningkatkan kegunaan dan nilai tambah dari zeolit. Data hasil penelitian menunjukkan bahwa xilenol orange (XO dapat diinterkalasikan ke dalam zeolit, hal ini dapat dilihat dari pita spektrum FTIR yang memiliki serapan pada bilangan gelombang 1383 cm-1, yaitu menunjukkan serapan dari S=O simetris dan asimetris pada gugus –SO3H,hal ini diduga karena XO memiliki gugus SO3 sehingga menyebabkan adanya serangan pada proton zeolit. Berdasarkan penelitian dapat disarikan bahwa xilanol orange dapat terinterkalasi pada zeolit alam Lampung dan dapat dimanfaatkan sebagai elektroda pendeteksi logam.

  10. Zeolite studies. Aluminium phosphate zeolites

    Energy Technology Data Exchange (ETDEWEB)

    Haegh, G.S.; Blindheim, U.

    1983-12-01

    Alpo-zeolites (ALPO4-zeolites) have been synthesized by hydrothermal synthesis in an autoclave from alumina, tetralkylammonium hydroxide and phosphorus acid. Catalysis tests with hydrocarbons indicate that the compounds have good olefinisomerization activity and selectivity.

  11. TPR investigations on the reducibility of Cu supported on Al2O3, zeolite Y and SAPO-5

    International Nuclear Information System (INIS)

    Hoang, Dang Lanh; Dang, Thi Thuy Hanh; Engeldinger, Jana; Schneider, Matthias; Radnik, Joerg; Richter, Manfred; Martin, Andreas

    2011-01-01

    Reducibility of Cu supported on Al 2 O 3 , zeolite Y and silicoaluminophosphate SAPO-5 has been investigated in dependence on the Cu content using a method combining conventional temperature programmed reduction (TPR) by hydrogen with reoxidation in N 2 O followed by a second the so-called surface-TPR (s-TPR). The method enables discrimination and a quantitative estimation of the Cu oxidation states +2, +1 and 0. The quantitative results show that the initial oxidation state of Cu after calcination in air at 400 deg. C, independent on the nature of the support, is predominantly +2. Cu 2+ supported on Al 2 O 3 is quantitatively reduced by hydrogen to metallic Cu 0 . Comparing the TPR of the samples calcined in air and that of samples additionally pre-treated in argon reveals that in zeolite Y and SAPO-5 Cu 2+ cations are stabilized as weakly and strongly forms. In both systems, strongly stabilized Cu 2+ ions are not auto-reduced by pre-treatment in argon at 650 deg. C, but are reduced in hydrogen to form Cu + . The weakly stabilized Cu 2+ ions, in contrast, may be auto-reduced by pre-treatment in argon at 650 deg. C forming Cu + but are reduced in hydrogen to metallic Cu 0 . - Graphical Abstract: TPR, TPR-(act), s-TPR and s-TPR-(act) profiles of (1.36)Cu/SAPO-5 (A), (4.55)Cu/SAPO-5 (B) and (9.19)Cu/SAPO-5 (C) samples. The intensities of TCD signals in (A) and (B) are multiplied by 4.5 and 2, respectively. Highlights: → Cu supported on SAPO-5, alumina and zeolite Y was investigated by TPR and s-TPR. → Cu oxidation states can be discriminated and quantitatively determined. → In zeolite Y and SAPO-5 Cu 2+ cations are stabilized at weak and strong forms. → Strongly stabilized Cu 2+ cannot be auto-reduced in argon at 650 deg. C.

  12. Synthesis of carbon-supported copper catalyst and its catalytic performance in methanol dehydrogenation

    Energy Technology Data Exchange (ETDEWEB)

    Shelepova, Ekaterina V. [Boreskov Institute of Catalysis SB RAS, pr. Ac. Lavrentieva, 5, Novosibirsk, 630090 (Russian Federation); National Research Tomsk Polytechnic University, Lenin av., 30, Tomsk, 634050 (Russian Federation); Vedyagin, Aleksey A., E-mail: vedyagin@catalysis.ru [Boreskov Institute of Catalysis SB RAS, pr. Ac. Lavrentieva, 5, Novosibirsk, 630090 (Russian Federation); National Research Tomsk Polytechnic University, Lenin av., 30, Tomsk, 634050 (Russian Federation); Ilina, Ludmila Yu.; Nizovskii, Alexander I. [Boreskov Institute of Catalysis SB RAS, pr. Ac. Lavrentieva, 5, Novosibirsk, 630090 (Russian Federation); Tsyrulnikov, Pavel G. [Institute of Hydrocarbon Processing SB RAS, Neftezavodskaya st., 54, Omsk, 644040 (Russian Federation)

    2017-07-01

    Highlights: • Carbon-supported copper catalyst was studied in dehydrogenation of methanol. • Reduction temperature affected size of Cu particles and Cu{sup 0}/Cu{sup 2+} ratio. • Reduction at 400 °C was required to obtain high methyl formate yield. - Abstract: Carbon-supported copper catalyst was prepared by incipient wetness impregnation of Sibunit with an aqueous solution of copper nitrate. Copper loading was 5 wt.%. Temperature of reductive pretreatment was varied within a range of 200–400 °C. The samples were characterized by transmission electron microscopy, X-ray diffraction analysis, X-ray photoelectron and X-ray absorption spectroscopies. Catalytic activity of the samples was studied in a reaction of methanol dehydrogenation. Silica-based catalyst with similar copper loading was used as a reference. It was found that copper is distributed over the surface of support in the form of metallic and partially oxidized particles of about 12–17 nm in size. Diminished interaction of copper with support was supposed to be responsible for high catalytic activity.

  13. Preparation and Characterization of Zeolite Membrane for Bioethanol Purification

    Directory of Open Access Journals (Sweden)

    Aprilina Purbasari

    2013-06-01

    Full Text Available The use of bioethanol as an alternative fuel with a purity of more than 99.5% wt has prompted research on bioethanol purification. One of the promising methods used for bioethanol purification is pervaporation membrane. This research is aimed to prepare and characterize zeolite membranes for pervaporation membrane. The membrane preparation consisted of two stages, namely support preparation and zeolite deposition on the support. In support preparation, α- alumina and kaolin with specific composition (50:30; 40:40; 50:30 was mixed with additives and water. After pugging and aging process, the mixture became paste and extruded into tubular shape. The tube was then calcined at temperature of 1250 °C for 3 hours. After that, zeolite 4A was deposited on the tubes using clear solution made of 10 %wt zeolite and 90 %wt water and heated at temperature of 80 °C for 3 hours. Furthermore, the resulting zeolite membranes was washed with deionized water for 5 minutes and dried in oven at temperature of 100 °C for 24 hours. Characterization of zeolite membranes included mechanical strength test, XRD, and SEM. In the mechanical strength test, the membrane sample with α- alumina:kaolin = 50:30 (membrane A has the highest mechanical strength of 46.65 N/mm2. Result of XRD analysis for the membrane A indicated that mullite and corundum phases were formed, which mullite phase was more dominant. Meanwhile the result of SEM analysis shows that zeolite crystals have been formed and covered the pores support, but the deposition of zeolite has not been optimal yet. The performance examination for bioethanol purification showed that the membrane could increase the purity of bioethanol from 95% to 98.5% wt. © 2013 BCREC UNDIP. All rights reservedReceived: 23rd October 2012; Revised: 15th February 2013; Accepted: 16th February 2013[How to Cite: Purbasari, A., Istirokhatun, T., Devi, A.M., Mahsunnah, L. , Susanto, H. (2013. Preparation and Characterization of Zeolite

  14. Synthesis of zeolite NaA membrane from fused fly ash extract.

    Science.gov (United States)

    Ameh, Alechine E; Musyoka, Nicholas M; Fatoba, Ojo O; Syrtsova, Daria A; Teplyakov, Vladimir V; Petrik, Leslie F

    2016-01-01

    Zeolite-NaA membranes were synthesized from an extract of fused South African fly ash on a porous titanium support by a secondary growth method. The influence of the synthesis molar regime on the formation of zeolite NaA membrane layer was investigated. Two synthesis mixtures were generated by adding either aluminium hydroxide or sodium aluminate to the fused fly ash extract. The feedstock material and the synthesized membranes were characterized by X-diffraction (XRD), scanning electron microscopy (SEM) and X-ray fluorescence spectroscopy (XRF). It was found by XRD and SEM that the cubic crystals of a typical zeolite NaA with a dense intergrown layer was formed on the porous Ti support. The study shows that the source of Al used had an effect on the membrane integrity as sodium aluminate provided the appropriate amount of Na(+) to form a coherent membrane of zeolite NaA, whereas aluminium hydroxide did not. Morphological, the single hydrothermal stage seeded support formed an interlocked array of zeolite NaA particles with neighbouring crystals. Also, a robust, continuous and well-intergrown zeolite NaA membrane was formed with neighbouring crystals of zeolite fused to each other after the multiple stage synthesis. The synthesized membrane was permeable to He (6.0 × 10(6) L m(-2)h(-1) atm(-1)) and CO2 (5.6 × 10(6) L m(-2)h(-1) atm(-1)), which indicate that the layer of the membrane was firmly attached to the porous Ti support. Membrane selectivity was maintained showing membrane integrity with permselectivity of 1.1, showing that a waste feedstock, fly ash, could be utilized for preparing robust zeolite NaA membranes on Ti support.

  15. Optimization of sodium loading on zeolite support for catalyzed transesterification of triolein with methanol.

    Science.gov (United States)

    Wang, Yu-Yuan; Chou, Hsin-Yu; Chen, Bing-Hung; Lee, Duu-Jong

    2013-10-01

    Optimization of sodium loading on zeolite HY for catalyzed transesterification of triolein in excess methanol to biodiesel was studied. Zeolite HY catalyst was activated by loading sodium ions to their surface via an ion-exchange method. The effects of ion-exchange process parameters, including the temperature, the process time, the pH value, as well as concentrations and sources of Na(+) cations (NaOH, NaCl and Na2SO4), on the conversion yield of triolein to biodiesel were investigated. Most of these Na(+)-activated zeolite HY catalysts could really facilitate the catalyzed transesterification reaction of triolein to biodiesel at a lower temperature near 65°C. Consequently, a high conversion yield of triglycerides to biodiesel at 97.3% was obtained at 65°C. Moreover, the durability of zeolite catalysts was examined as well. Catalytic performance tests of these zeolite catalysts in transesterification did not show a significant decrease in catalysis at least for three batch cycles. Copyright © 2013 Elsevier Ltd. All rights reserved.

  16. Fabrication and evaluation of novel zeolite membranes to control the neoplastic activity and anti-tumoral drug treatments in human breast cancer cells. Part 1: Synthesis and characterization of Pure Zeolite Membranes and Mixed Matrix Membranes for adhesion and growth of cancer cells

    International Nuclear Information System (INIS)

    Tavolaro, Palmira; Martino, Guglielmo; Andò, Sebastiano; Tavolaro, Adalgisa

    2016-01-01

    Novel pure and hybrid zeolite membranes were prepared with appropriate different physicochemical characteristics such as frameworks, hydrophilicity, crystal size, chemical composition, acid-base properties (Point of Zero Charge, PZC) and surface morphology and used in inorganic cell/scaffold constructs. Because the control of cell interactions, as the adhesion, proliferation, remodelling and mobility, is important for differentiation and progression of tumors, this work focused on response of cancer cells adhered and grown on synthesized zeolite surfaces in order to study the influence of these scaffolds in controlled conditions. We have selected the MCF-7 and MDA-MB-231 human breast cancer cell line as model tumor cell lines. This study showed that all the zeolite membranes synthesized are excellent scaffolds because they are very selective materials to support the adhesion and growth of neoplastic cells. All zeolite scaffolds were characterized by FESEM, FTIR ATR, XRD, AFM, PZC and contact angle analyses. Cell adhesion, viability and morphology were measured by count, MTT assay and FESEM microphotography analysis, at various incubation times. - Highlights: • Novel pure and hybrid zeolite scaffolds were developed. • PZMs and MMMs were characterized and used with human cancer cells. • A systematic study of zeolite scaffolds influence on cell adhesion and morphology was performed. • The PZC value of zeolite membranes controls the cell-cell and scaffold-cell interactions.

  17. Fabrication and evaluation of novel zeolite membranes to control the neoplastic activity and anti-tumoral drug treatments in human breast cancer cells. Part 1: Synthesis and characterization of Pure Zeolite Membranes and Mixed Matrix Membranes for adhesion and growth of cancer cells

    Energy Technology Data Exchange (ETDEWEB)

    Tavolaro, Palmira, E-mail: p.tavolaro@unical.it [Department of Pharmacy, Health and Nutritional Sciences, University of Calabria, Cubo 4/c, 87036 Rende (Italy); Martino, Guglielmo [Department Di.B.E.S.T. (Biologia, Ecologia, Scienze della Terra), Unit of Physiology, University of Calabria, Cubo 4/c, 87036 Rende (Italy); Andò, Sebastiano [Department of Pharmacy, Health and Nutritional Sciences, University of Calabria, Cubo 4/c, 87036 Rende (Italy); Tavolaro, Adalgisa [Research Institute on Membrane Technology, Unit of Zeolite Membranes, ITM-CNR, University of Calabria, Cubo 17/c, 87036 Rende (Italy)

    2016-12-01

    Novel pure and hybrid zeolite membranes were prepared with appropriate different physicochemical characteristics such as frameworks, hydrophilicity, crystal size, chemical composition, acid-base properties (Point of Zero Charge, PZC) and surface morphology and used in inorganic cell/scaffold constructs. Because the control of cell interactions, as the adhesion, proliferation, remodelling and mobility, is important for differentiation and progression of tumors, this work focused on response of cancer cells adhered and grown on synthesized zeolite surfaces in order to study the influence of these scaffolds in controlled conditions. We have selected the MCF-7 and MDA-MB-231 human breast cancer cell line as model tumor cell lines. This study showed that all the zeolite membranes synthesized are excellent scaffolds because they are very selective materials to support the adhesion and growth of neoplastic cells. All zeolite scaffolds were characterized by FESEM, FTIR ATR, XRD, AFM, PZC and contact angle analyses. Cell adhesion, viability and morphology were measured by count, MTT assay and FESEM microphotography analysis, at various incubation times. - Highlights: • Novel pure and hybrid zeolite scaffolds were developed. • PZMs and MMMs were characterized and used with human cancer cells. • A systematic study of zeolite scaffolds influence on cell adhesion and morphology was performed. • The PZC value of zeolite membranes controls the cell-cell and scaffold-cell interactions.

  18. Mesoporous zeolite single crystal catalysts: Diffusion and catalysis in hierarchical zeolites

    DEFF Research Database (Denmark)

    Christensen, Christina Hviid; Johannsen, Kim; Toernqvist, Eric

    2007-01-01

    During the last years, several new routes to produce zeolites with controlled mesoporosity have appeared. Moreover, an improved catalytic performance of the resulting mesoporous zeolites over conventional zeolites has been demonstrated in several reactions. In most cases, the mesoporous zeolites...... exhibit higher catalytic activity, but in some cases also improved selectivity and longer catalyst lifetime has been reported. The beneficial effects of introducing mesopores into the zeolites has in most instances been attributed to improved mass transport to and from the active sites located...... in the zeolite micropores. Here, we briefly discuss the most important ways of introducing mesopores into zeolites and, for the first time, we show experimentally that the presence of mesopores dramatically increases the rate of diffusion in zeolite catalysts. This is done by studying the elution of iso...

  19. Catalytic Performance of Zeolite-Supported Vanadia in the Aerobic Oxidation of 5-hydroxymethylfurfural to 2,5- diformylfuran

    DEFF Research Database (Denmark)

    Sádaba, Irantzu; Gorbanev, Yury; Kegnæs, Søren

    2013-01-01

    on the four different zeolite supports H-beta, H-Y, H-mordenite, and H-ZSM-5 with 1–10 wt% vanadia loading were prepared and characterized by nitrogen physisorption, X-ray powder diffraction, scanning electron  microscopy, ammonia temperature-programmed desorption, Raman spectroscopy and UV...

  20. Zeolite from fly ash: synthesis and characterization

    Indian Academy of Sciences (India)

    Unknown

    to attempt making zeolite from fly ash (Höller and Wir- sching 1985; Henmi ... thermal treatment method to synthesize low silica NaX- type zeolite from .... catalytic applications. Mixture of ... amount of Fe2O3 and the oxides of Mg, Ca, P, Ti etc. The chemical ..... This work is partly supported by the Ministry of Human. Resource ...

  1. Hydrothermal conversion of FAU zeolite into RUT zeolite in TMAOH system

    OpenAIRE

    Jon, Hery; Takahashi, Shoutarou; Sasaki, Hitoshi; Oumi, Yasunori; Sano, Tsuneji

    2008-01-01

    The highly crystalline and pure RUT (RUB-10) zeolite could be obtained from the hydrothermal conversion of FAU zeolite used as a crystalline Si/Al source in tetramethylammonium hydroxide (TMAOH) media. As compared to amorphous silica/Al(OH)3 and amorphous silica/γ-Al2O3 sources, the crystallization rate for the formation of RUT zeolite was clearly faster when FAU zeolite was employed as the Si/Al source. Moreover, it was found that the hydrothermal conversion of FAU zeolite into RUT zeolite d...

  2. Bendable Zeolite Membranes: Synthesis and Improved Gas Separation Performance.

    Science.gov (United States)

    Wang, Bo; Ho, W S Winston; Figueroa, Jose D; Dutta, Prabir K

    2015-06-23

    Separation and sequestration of CO2 emitted from fossil energy fueled electric generating units and industrial facilities will help in reducing anthropogenic CO2, thereby mitigating its adverse climate change effects. Membrane-based gas separation has the potential to meet the technical challenges of CO2 separation if high selectivity and permeance with low costs for large-scale manufacture are realized. Inorganic zeolite membranes in principle can have selectivity and permeance considerably higher than polymers. This paper presents a strategy for zeolite growth within the pores of a polymer support, with crystallization time of an hour. With a thin coating of 200-300 nm polydimethylsiloxane (PDMS) on the zeolite-polymer composite, transport data for CO2/N2 separation indicate separation factors of 35-45, with CO2 permeance between 1600 and 2200 GPU (1 GPU = 3.35 × 10(-10) mol/(m(2) s Pa)) using dry synthetic mixtures of CO2 and N2 at 25 °C. The synthesis process results in membranes that are highly reproducible toward transport measurements and exhibit long-term stability (3 days). Most importantly, these membranes because of the zeolite growth within the polymer support, as contrasted to conventional zeolite growth on top of a support, are mechanically flexible.

  3. The role of natural zeolite and of zeolite modified with ammnonium ions to reduce the uptake of lead, zinc, copper and iron ions in Hieracium aurantium and Rumex acetosella grown on tailing ponds

    Directory of Open Access Journals (Sweden)

    Anca PETER

    2011-11-01

    Full Text Available The objective of this research is to determine if zeolite modified with ammonium ions has a higher capacity than natural zeolite to protect Hieracium aurantium and Rumex acetosella growing on tailing ponds, by reducing the quantity of metal ions these plants would accumulate in their roots and leaves. The influence of the amount of zeolite in the substrate (5% and 10% mass percentage was also studied. The experiments were carried out in laboratory and the concentration of the ions of heavy metal in roots and leaves, after 38 days of growth was established by Flame Atomic Adsorption Spectroscopy. The pH, conductivity and redox potential for each of the substrate considered were measured. The results were statistically processed using the one-way analysis of variance (one-way ANOVA. FTIR analyses were performed to establish the structural differences between the natural and modified zeolite. Hieracium aurantium and Rumex acetosella accumulate a smaller quantity of metal ions in roots and leaves in the presence of zeolite modified with ammonium ions than in the presence of natural zeolite. Laboratory tests showed that Hieracium aurantium is more tolerant to ions of heavy metals than Rumex acetosella, as demonstrated by their translocation factors.In terms of reducing the uptake of ions of heavy metals, only the zeolite modified with ammonium has a significant protective effecton Hieracium aurantium, while both natural zeolite and zeolite modified demonstrate a significant role for Rumex acetosella, asrevealed by statistical tests.

  4. Potential and challenges of zeolite chemistry in the catalytic conversion of biomass.

    Science.gov (United States)

    Ennaert, Thijs; Van Aelst, Joost; Dijkmans, Jan; De Clercq, Rik; Schutyser, Wouter; Dusselier, Michiel; Verboekend, Danny; Sels, Bert F

    2016-02-07

    Increasing demand for sustainable chemicals and fuels has pushed academia and industry to search for alternative feedstocks replacing crude oil in traditional refineries. As a result, an immense academic attention has focused on the valorisation of biomass (components) and derived intermediates to generate valuable platform chemicals and fuels. Zeolite catalysis plays a distinct role in many of these biomass conversion routes. This contribution emphasizes the progress and potential in zeolite catalysed biomass conversions and relates these to concepts established in existing petrochemical processes. The application of zeolites, equipped with a variety of active sites, in Brønsted acid, Lewis acid, or multifunctional catalysed reactions is discussed and generalised to provide a comprehensive overview. In addition, the feedstock shift from crude oil to biomass involves new challenges in developing fields, like mesoporosity and pore interconnectivity of zeolites and stability of zeolites in liquid phase. Finally, the future challenges and perspectives of zeolites in the processing of biomass conversion are discussed.

  5. Effects of supporting electrolytes on copper electroplating for filling through-hole

    International Nuclear Information System (INIS)

    Chen, Chien-Hung; Lu, Chun-Wei; Huang, Su-Mei; Dow, Wei-Ping

    2011-01-01

    Highlights: → The through-holes of a printed circuit boardare directly filled by copper electroplating using single organic additive. → The inhibiting strength of the additive on copper deposition is related to a supporting electrolyte. → H 2 SO 4 strongly enhances the inhibiting strength of the additive and results in a conformal deposition, whereas Na 2 SO 4 and K 2 SO 4 do not affect the inhibiting strength and lead to good filling capability. - Abstract: The filling of micron through-holes (THs) in a printed circuit board (PCB) by copper electroplating was investigated in this study. The role of supporting electrolytes, such as H 2 SO 4 , Na 2 SO 4 and K 2 SO 4 , was explored using practical TH filling plating and linear-sweep voltammetry (LSV) analysis of plating solutions. The copper could selectively fill THs using one organic additive, namely, tetranitroblue tetrazolium chloride (TNBT), as an inhibitor. The inhibiting strength of TNBT depended on the supporting electrolytes. Although H 2 SO 4 could enhance the inhibiting strength of TNBT, it also decreased the filling capability of the copper plating solution; Na 2 SO 4 and K 2 SO 4 did not enhance the inhibiting strength of TNBT but they increased the filling capability of the copper plating solution. Additionally, the protons could chemically interact with TNBT to form precipitate, whereas sodium and potassium ions did not easily interact with TNBT. The filling capability of the copper plating solution using Na 2 SO 4 and K 2 SO 4 as supporting electrolytes could be greatly improved by adding a small amount of bis(3-sulfopropyl)-disulfide (SPS) and poly(ethylene glycol) (PEG) with a molecular weight of 600.

  6. Aluminum-rich mesoporous MFI - type zeolite single crystals

    DEFF Research Database (Denmark)

    Kustova, Marina; Kustov, Arkadii; Christensen, Christina Hviid

    2005-01-01

    Zeolitcs are crystalline materials, which are widely used as solid acid catalysts and supports in many industrial processes. Recently, mesoporous MFI-type zeolite single crystals were synthesized by use of carbon particles as a mesopore template and sodium aluminate as the aluminum Source....... With this technique, only zeolites with relatively low Al contents were reported (Si/Al ratio about 100). In this work, the preparation of aluminum-rich mesoporous MFI-type zeolite single crystals (Si/Al similar to 16-50) using aluminum isopropoxide as the aluminum Source is reported for the first time. All samples...... are characterized by X-ray powder diffraction (XRD), scanning electron microscopy (SEM), ammonia temperature programmed desorption (NH3-TPD), and N-2 adsorption measurements. The obtained zeolites combine the high crystallinity and the characteristic micropores of zeolites with an intracrystalline mesopore system...

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

    Science.gov (United States)

    Nowicki, Janusz; Mokrzycki, Łukasz; Sulikowski, Bogdan

    2015-04-08

    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.

  8. Use of zeolite for removing ammonia and ammonia-caused toxicity in marine toxicity identification evaluations.

    Science.gov (United States)

    Burgess, R M; Perron, M M; Cantwell, M G; Ho, K T; Serbst, J R; Pelletier, M C

    2004-11-01

    Ammonia occurs in marine waters including effluents, receiving waters, and sediment interstitial waters. At sufficiently high concentrations, ammonia can be toxic to aquatic species. Toxicity identification evaluation (TIE) methods provide researchers with tools for identifying aquatic toxicants. For identifying ammonia toxicity, there are several possible methods including pH alteration and volatilization, Ulva lactuca addition, microbial degradation, and zeolite addition. Zeolite addition has been used successfully in freshwater systems to decrease ammonia concentrations and toxicity for several decades. However, zeolite in marine systems has been used less because ions in the seawater interfere with zeolite's ability to adsorb ammonia. The objective of this study was to develop a zeolite method for removing ammonia from marine waters. To accomplish this objective, we performed a series of zeolite slurry and column chromatography studies to determine uptake rate and capacity and to evaluate the effects of salinity and pH on ammonia removal. We also assessed the interaction of zeolite with several toxic metals. Success of the methods was also evaluated by measuring toxicity to two marine species: the mysid Americamysis bahia and the amphipod Ampelisca abdita. Column chromatography proved to be effective at removing a wide range of ammonia concentrations under several experimental conditions. Conversely, the slurry method was inconsistent and variable in its overall performance in removing ammonia and cannot be recommended. The metals copper, lead, and zinc were removed by zeolite in both the slurry and column treatments. The zeolite column was successful in removing ammonia toxicity for both the mysid and the amphipod, whereas the slurry was less effective. This study demonstrated that zeolite column chromatography is a useful tool for conducting marine water TIEs to decrease ammonia concentrations and characterize toxicity.

  9. Redox behavior of transition metal ions in zeolites--7. Characterization of a nickel metal phase in zeolite NaY

    Energy Technology Data Exchange (ETDEWEB)

    Jacobs, P.A. (Katholieke Univ. Leuven); Derouane, E.G.; Nijs, H.; Verdonck, J.; Gilson, J.P.; Simoens, A.J.

    1979-01-01

    NiY zeolite was calcined under steaming and nonsteaming conditions, at 823/sup 0/ and 1200/sup 0/K, respectively, then reduced in hydrogen at 673/sup 0/ to 873/sup 0/K for two hours. Characterization of the Ni(0) metal phase by temperature programed reduction and oxidation techniques and by ferromagnetic resonance spectroscopy indicated a bidisperse metal particle size distribution. Inside the zeolite, small Ni(0) particles were found, the sizes of which were limited by the dimensions of the supercage or of the structural defects occurring with high reduction temperatures; the particles interacted strongly with the support or were Vertical Bar3; 100Vertical Bar3< reduced. On the zeolite surface, large Ni(0) particles were formed which were ellipsoidal and completely reduced and did not interact with the support. Calcining under steaming conditions did not affect the reducibility of the nickel but did promote sintering during reduction.

  10. Adsorption of CO2 in FAU zeolites: Effect of zeolite composition

    Czech Academy of Sciences Publication Activity Database

    Thang, H. V.; Grajciar, L.; Nachtigall, P.; Bludský, Ota; Areán, C. O.; Frýdová, E.; Bulánek, R.

    2014-01-01

    Roč. 227, May 15 (2014), s. 50-56 ISSN 0920-5861 R&D Projects: GA ČR GBP106/12/G015 Institutional support: RVO:61388963 Keywords : DFT/CC * CO2 * carbon capture and storage * zeolite * adsorption calorimetry Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 3.893, year: 2014

  11. Effects of Chemical Fertilizer, Algea Compost and Zeolite on Green Bean Yield

    Directory of Open Access Journals (Sweden)

    Aysun Türkmen

    2017-03-01

    Full Text Available The present study used chemical fertilizer, brown algae compost and zeolite carried out in the field of Giresun Hazelnut Research Center between May-November 2014 in pots according to randomized blog design as three replicate each. Treatment groups were consist of eight different combinations as follow; G1-Control, G2-Zeolite, G3-Compost, G4-Chemical Fertilizer, G5-Zeolite+Compost, G6-Zeolite+Chemical Fertilizer, G7-Compost+ Chemical Fertilizer, G8-Compost+Zeolite+ Chemical Fertilizer. The brown algae (Cystoseira sp. were used as compost material. These combinations were applied to green beans (Phaseolus vulgaris. The green beans were seeded by hand to arrange planting depth of 5-6 cm and 20 seeds/m2. Except control group, each treatment was added fertilizers as 50 g zeolite, 50 g compost, and 25 g chemical according to treatment design. Half of the chemical fertilizers were added at seeding time and the rest after two weeks. Collected soil samples were analyzed right after harvest, the greatest values of treatment groups were determined as; Carbon% G1: 5.08, nitrogen G3: 0.09 ppm, sodium G5: 139 ppm, potassium G6 and G8: 5 ppm, magnesium G2: 1865 ppm, calcium G6: 8.33 ppm, manganese G2: 359 ppm, iron G6 : 16070 ppm, cobalt G6 and G7: 7.91 ppm, copper G2: 17.5 ppm, zinc G8: 28.0 ppm, selenium G7: 4.17 ppm, cadmium G5: 0.08 ppm, lead G4: 5.31 ppm. The greatest harvest value as g/m2 was obtained from zeolite only group G2 with 273 while the lowest was obtained from Compost only group G3 with 113 g/m2, obviously showing the effectiveness of zeolite only application moreover, also thinking that better results may get if the present study run for longer period.

  12. Structure and Reactivity of Zeolite- and Carbon-Supported Catalysts for the Oxidative Carbonylation of Alcohols

    OpenAIRE

    Briggs, Daniel Neal

    2010-01-01

    AbstractStructure and Reactivity of Zeolite- and Carbon-Supported Catalysts for the Oxidative Carbonylation of AlcoholsbyDaniel Neal BriggsDoctor of Philosophy in Chemical EngineeringUniversity of California, BerkeleyProfessor Alexis T. Bell, Chair The oxidative carbonylation of alcohols to produce dialkyl carbonates is a process that takes place commercially in a slurry of cuprous chloride in the appropriate alcohol. While this process is chemically efficient, it incurs costs in terms of ene...

  13. Synthesis of Zeolite NaA from Low Grade (High Impurities) Indonesian Natural Zeolite

    OpenAIRE

    Mustain, Asalil; Wibawa, Gede; Nais, Mukhammad Furoiddun; Falah, Miftakhul

    2014-01-01

    The zeolite NaA has been successfully synthesized from the low grade natural zeolite with high impurities. The synthesis method was started by mixing natural zeolite powder with NH4Cl aqueous solution in the reactor as pretreatment. The use of pretreatment was to reduce the impurities contents in the zeolite. The process was followed by alkaline fusion hydrothermal treatment to modify the framework structure of natural zeolite and reduce the SiO2/Al2O3 ratio. Finally, the synthesized zeolite ...

  14. Influence of zeolite structure on the activity and durability of Co-Pd-zeolite catalysts in the reduction of NOx with methane

    International Nuclear Information System (INIS)

    Pieterse, J.A.Z.; Van den Brink, R.W.; Booneveld, S.; De Bruijn, F.A.

    2003-01-01

    Selective catalytic reduction of NO with CH 4 was studied over ZSM-5, MOR, FER and BEA zeolite-based cobalt (Co) and palladium (Pd) catalysts in the presence of oxygen and water. As compared to other catalytic systems reported in literature for CH 4 -SCR in the presence of water, zeolite supported Co-Pd combination catalysts are very active and selective. The most active catalysts, based on MOR and ZSM-5, are characterised by well-dispersed Pd ions in the zeolite that activate methane. Wet ion exchange is a good method to achieve high dispersion of Pd provided that it is carried out in a competitive manner. The presence of cobalt (Co 3 O 4 , Co-oxo ions) boosts SCR activity by oxidising NO to NO 2 . The activity of the zeolite-based Co-Pd combination catalysts decreases with prolonged times on stream. The severity of the deactivation was found to be different for different zeolite topologies. The characterisation and evaluation of freshly calcined catalysts and spent catalysts show two things that occur during reaction: (1) zeolite solvated metal cations disappear in favour of (inactive) metal oxides and presumably larger metal entities, i.e. loss of dispersion; (2) loss of crystallinity affiliated with steam-dealumination and the concomitant formation of extra-framework aluminium (EFAL) in the presence of water. Both phenomena strongly depend on the (reaction) temperature. The deactivation of Co-Pd-zeolite resembles the deactivation of Pd-zeolite. Hence, future research could encompass the stabilisation of Pd (cations) in the zeolite pores by exploring additives other than cobalt. For this, detailed understanding on the siting of Pd in zeolites is important

  15. The study of methanol transformation over Cu-modified ZSM-5, Beta zeolite and MCM-41 mesoporous silica using 11C-radioisotope labeling

    International Nuclear Information System (INIS)

    Sarkadi-Priboczki, E.; Kovacs, Z.

    2004-01-01

    Complete text of publication follows. The copper-containing zeolites and mesoporous silica, among other metals, are suitable for dehydrogenation of methanol. The Cu transition metal determines the route of methanol conversion on supports of ZSM-5 and Beta zeolite as well as MCM-41 mesoporous silica. The catalysis mechanism and the catalytic property are concluded from the composition of methanol derivates over Cu-modified catalysts. The Cu ion-exchanged ZSM-5 and Beta zeolite and MCM-41 mesoporous silica were synthesized and characterized using X-ray power diffraction, scanning electron microscope, nitrogen and pyridine adsorption, X-ray fluorescency and FTIR spectroscopy. The 11 C-radioactive labeling method ( 11 C radioisotope, T 1/2 = 20 min, is a gamma emitter by annihilation of its positron) is suitable for following the process of 11 C-methanol con- version i.e. adsorption, desorption and catalytic transformation as well as for investigation of small amounts of molecules over catalysts by very sensitive radioactivity detectors.The 11 C radioisotope was produced at cyclotron and the 11 C-methanol was synthesized by a classical radiochemical method. After catalysis the 11 C-radioactive and non radioactive volatile products were identified by radiogas chromatography hereby radiolabeled compound and -derivates were distinguished from other participant natural, nonradioactive carbon compounds. Along radioactive products dimethyl ether and small hydrocarbons products were formed by Bronsted acid sites of catalysts while formaldehyde and small methyl formate were formed by Cu metal over bifunctional Cu-ZSM-5, Cu-Beta zeolite and mesoporous Cu-MCM-41 silica at 240 deg C. The detection of methoxy methanol and dimethoxy methane confirmed the simultaneous presence of acid and basic sites of catalysts. At higher temperature (400 deg C) the CO and CO 2 final products were dominated. In our previous works, methanol conversion to hydrocarbons was observed by dehydration

  16. Electron irradiation of zeolites

    International Nuclear Information System (INIS)

    Wang, S.X.; Wang, L.M.; Ewing, R.C.

    1999-01-01

    Three different zeolites (analcime, natrolite, and zeolite-Y) were irradiated with 200 keV and 400 keV electrons. All zeolites amorphized under a relatively low electron fluence. The transformation from the crystalline-to-amorphous state was continuous and homogeneous. The electron fluences for amorphization of the three zeolites at room temperature were: 7.0 x 10 19 e - /cm 2 (analcime), 1.8 x 10 20 e - /cm 2 (natrolite), and 3.4 x 10 20 e - /cm 2 (zeolite-Y). The different susceptibilities to amorphization are attributed to the different channel sizes in the structures which are the pathways for the release of water molecules and Na + . Natrolite formed bubbles under electron irradiation, even before complete amorphization. Analcime formed bubbles after amorphization. Zeolite-Y did not form bubbles under irradiation. The differences in bubble formation are attributed to the different channel sizes of the three zeolites. The amorphization dose was also measured at different temperatures. An inverse temperature dependence of amorphization dose was observed for all three zeolites: electron dose for amorphization decreased with increasing temperature. This unique temperature effect is attributed to the fact that zeolites are thermally unstable. A semi-empirical model was derived to describe the temperature effect of amorphization in these zeolites

  17. Applications of natural zeolites on agriculture and food production.

    Science.gov (United States)

    Eroglu, Nazife; Emekci, Mevlut; Athanassiou, Christos G

    2017-08-01

    Zeolites are crystalline hydrated aluminosilicates with remarkable physical and chemical properties, which include losing and receiving water in a reverse way, adsorbing molecules that act as molecular sieves, and replacing their constituent cations without structural change. The commercial production of natural zeolites has accelerated during the last 50 years. The Structure Commission of the International Zeolite Association recorded more than 200 zeolites, which currently include more than 40 naturally occurring zeolites. Recent findings have supported their role in stored-pest management as inert dust applications, pesticide and fertilizer carriers, soil amendments, animal feed additives, mycotoxin binders and food packaging materials. There are many advantages of inert dust application, including low cost, non-neurotoxic action, low mammalian toxicity and safety for human consumption. The latest consumer trends and government protocols have shifted toward organic origin materials to replace synthetic chemical products. In the present review, we summarize most of the main uses of zeolites in food and agruculture, along with the with specific paradigms that illustrate their important role. © 2017 Society of Chemical Industry. © 2017 Society of Chemical Industry.

  18. The fabrication of porous 4A-zeolite-supported Ag nanoparticles catalysts and its catalytic activity for styrene epoxidation

    Directory of Open Access Journals (Sweden)

    Youkui Wu

    Full Text Available Binderless hierarchically porous 4A-zeolite has been successful produced through hydrothermal crystallization, in which silicon-aluminum sol binded to the carbon nanofibers (CNFs, that is to say, where the CNFs powder was coated during the crystallization 4A-zeolite. The mixing of silica-alumina sol and CNFs was only a simple physical mixing process. The samples of micropores-macroporous hierarchical 4A-zeolite (P-4A-zeolite was analyzed by a series of characterization techniques, such as field emission scanning electron microscope (FESEM, transmission electron microscopy (TEM, simultaneous thermal analysis (STA and CO2 adsorption-desorption (BET and BJH, and so on. In addition, the adsorption test of silver nanoparticles was carried out. The characterization results indicated the presence of micropores and the formation of macroporous. At the same time, silver adsorption test proved that the prepared P-4A-zeolite had good adsorption performance and the catalytic performance of Ag/P-4A-zeolite was further investigated through the epoxidation of styrene. Keywords: Carbon nanofibers, Porous 4A-zeolite, Silver nanoparticles, Styrene epoxidation

  19. Distribution of metal and adsorbed guest species in zeolites

    Energy Technology Data Exchange (ETDEWEB)

    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.

  20. Distribution of metal and adsorbed guest species in zeolites

    International Nuclear Information System (INIS)

    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 129 Xe NMR spectroscopy an important diagnostic probe of metal clustering and adsorbate distribution processes in zeolites. The utility of 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, 129 Xe NMR is insensitive to fine structural details at room temperature

  1. Positron annihilation in modified zeolites LTA and 13X

    Energy Technology Data Exchange (ETDEWEB)

    Cabral-Prieto, A.; Garcia-Sosa, I.; Jimenez-Becerril, J. [Departamento de Quimica, Instituto Nacional de Investigaciones Nucleares, Apartado Postal 18-1027, Col. Escandon, Del. M. Hidalgo, Mexico D. F., c. p. 11801 (Mexico); Lopez-Castanares, R.; Olea-Cardoso, O. [Facultad de Quimica, Universidad Autonoma del Estado de Mexico, Paseo Tollocan esquina paseo Tollocan, esquina paseo Colon, Toluca, c. p. 50120, Estado de Mexico (Mexico)

    2007-07-01

    The pick-off annihilation lifetimes of o -Ps, {tau}{sub po}, in dehydrated Co{sup 2+} and Mn{sup 2+} exchanged zeolites LTA, in dehydrated Co{sup 2+} exchanged zeolite 13X, and in dehydrated Na{sup +} zeolites LTA and 13X, are estimated. Although {tau}{sub po} can be estimated from the lifetime spectra of the cation exchanged zeolites LTA and 13X, this lifetime can not be estimated from those spectra of Na{sup +} zeolite LTA unambiguously. The estimated pick-off lifetimes due to the annihilation of o-Ps in the internal walls of the zeolites are systematically lower than the average lifetime of p-Ps and o-Ps in vacuum {tau}{sub a}=0.5 ns. Since the pick-off process of o-Ps occurs particularly on the internal cavity walls of dehydrated zeolites, the replacement of {tau}{sub a} by {tau}{sub po} within the classical model of Tao-Eldrup to calculate cavity radius should provide more realistic cavity radii of these porous materials than when using {l_brace}{tau}{sub a}{r_brace}. This suggestion is supported by previous and present results. (copyright 2007 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  2. Hierarchical zeolites from class F coal fly ash

    Science.gov (United States)

    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

  3. Removal of ethylene from air stream by adsorption and plasma-catalytic oxidation using silver-based bimetallic catalysts supported on zeolite.

    Science.gov (United States)

    Trinh, Quang Hung; Lee, Sang Baek; Mok, Young Sun

    2015-03-21

    Dynamic adsorption of ethylene on 13X zeolite-supported Ag and Ag-M(x)O(y) (M: Co, Cu, Mn, and Fe), and plasma-catalytic oxidation of the adsorbed ethylene were investigated. The experimental results showed that the incorporation of Ag into zeolite afforded a marked enhancement in the adsorptivity for ethylene. The addition of transition metal oxides was found to have a positive influence on the ethylene adsorption, except Fe(x)O(y). The presence of the additional metal oxides, however, appeared to somewhat interrupt the diffusion of ozone into the zeolite micro-pores, leading to a decrease in the plasma-catalytic oxidation efficiency of the ethylene adsorbed there. Among the second additional metal oxides, Fe(x)O(y) was able to reduce the emission of ozone during the plasma-catalytic oxidation stage while keeping a high effectiveness for the oxidative removal of the adsorbed ethylene. The periodical treatment consisting of adsorption followed by plasma-catalytic oxidation may be a promising energy-efficient ethylene abatement method. Copyright © 2014 Elsevier B.V. All rights reserved.

  4. Synthesis of zeolite-P from coal fly ash derivative and its utilisation in mine-water remediation

    Directory of Open Access Journals (Sweden)

    Leslie F. Petrik

    2010-05-01

    Full Text Available Solid residues resulting from the active treatment of acid mine drainage with coal fly ash were successfully converted to zeolite-P under mild hydrothermal treatment conditions. Scanning electron microscopy showed that the zeolite-P product was highly crystalline. The product had a high cation exchange capacity (178.7 meq / 100 g and surface area (69.1 m2/g and has potential application in waste-water treatment. A mineralogical analysis of the final product identified zeolite-P, as well as mullite and quartz phases, which indicated incomplete dissolution of the fly ash feedstock during the ageing step. Further optimisation of the synthesis conditions would be required to attain complete utilisation of the feedstock. The zeolite-P was tested for decontamination potential of circumneutral mine water. High removal efficiency was observed in the first treatment, but varied for different contaminants. The synthesised zeolite-P exhibited a high efficiency for the removal of heavy metal cations, such as aluminium, iron, manganese, zinc, copper and nickel, from contaminated mine water, even with repeated use. For potassium, calcium, strontium and barium, the removal was only efficient in the first treatment and decreased rapidly with subsequent treatments, indicating preferential adsorption of the other metals. A continuous release of sodium was observed during decontamination experiments, which decreased with subsequent treatments, confirming that sodium was the main exchangeable charge-balancing cation present in the zeolite-P product.

  5. Synthesis of zeolite NaA membrane from fused fly ash extract

    CSIR Research Space (South Africa)

    Ameh, AE

    2016-01-01

    Full Text Available Zeolite-NaA membranes were synthesized from an extract of fused South African fly ash on a porous titanium support by a secondary growth method. The influence of the synthesis molar regime on the formation of zeolite NaA membrane layer...

  6. XAFS Study on TiO2 Photocatalyst Loaded on Zeolite Synthesized from Steel Slag

    International Nuclear Information System (INIS)

    Kuwahara, Yasutaka; Ohmichi, Tetsutaro; Mori, Kosuke; Katayama, Iwao; Yamashita, Hiromi

    2007-01-01

    The convenient route for the synthesis of Y-zeolites by utilizing steel slag as a material source was developed. Through hydrothermal treatment, well-crystallized Y-zeolite was obtained. We also synthesized TiO2-loaded Y-zeolites by an impregnation method. The structure of titanium oxide species highly dispersed on the zeolite, which couldn't be detected by XRD patterns, was investigated by XAFS analysis. Photocatalytic activity for decomposition of 2-propanol in liquid phase was found to be enhanced by the hydrophobic surface property of zeolite. It has been demonstrated that the zeolite synthesized from steel slag would be applicable as a promising support of TiO2 photocatalyst

  7. Use of Natural Zeolite to Upgrade Activated Sludge Process

    Directory of Open Access Journals (Sweden)

    Hanife Büyükgüngör

    2003-01-01

    Full Text Available The objective of this study was to achieve better efficiency of phosphorus removal in an enhanced biological phosphorus removal process by upgrading the system with different amounts of natural zeolite addition. The system performance for synthetic wastewater containing different carbon sources applied at different initial concentrations of phosphorus, as well as for municipal wastewater, was investigated. Natural zeolite addition in the aerobic phase of the anaerobic/aerobic bioaugmented activated sludge system contributed to a significant improvement of phosphorus removal in systems with synthetic wastewater and fresh municipal wastewater. Improvement of phosphorus removal with regard to the control reactors was higher with the addition of 15 than with 5 g/L of natural zeolite. In reactors with natural zeolite addition with regard to the control reactors significantly decreased chemical oxygen demand, ammonium and nitrate, while higher increment and better-activated sludge settling were achieved, without changes in the pH-values of the medium. It was shown that the natural zeolite particles are suitable support material for the phosphate-accumulating bacteria Acinetobacter calcoaceticus (DSM 1532, which were adsorbed on the particle surface, resulting in increased biological activity of the system. The process of phosphorus removal in a system with bioaugmented activated sludge and natural zeolite addition consisted of: metabolic activity of activated sludge, phosphorus uptake by phosphate-accumulating bacteria adsorbed on the natural zeolite particles and suspended in solution, and phosphorus adsorption on the natural zeolite particles.

  8. Synthesis of zeolite-zeolite (mfi-fau) composite catalysts for the isomerization of n-hexane

    International Nuclear Information System (INIS)

    Ghouri, A.S; Usman, M.R.

    2017-01-01

    In this research work, the aim is to produce a relatively novel zeolite-zeolite (MFI-FAU) composite catalyst having better potential of catalyzing isomerization of lighter hydrocarbons such as light naphtha, n-pentane, n-hexane, n-heptane and mixture thereof. A series of zeolite-zeolite (MFI-FAU) composite catalysts have been synthesized by incorporating previous practices and techniques. The catalytic performance of as-synthesized zeolite-zeolite (MFI-FAU) composite catalysts have been investigated by isomerizing 95% pure n-hexane in conventional fixed bed flow micro-reactor at temperature 200-240 ºC under atmospheric pressure. In order to explore chemical and physical features of zeolite-zeolite (MFI-FAU) composite catalysts, they are examined and characterized using powder X-ray diffraction (XRD), scanning electron microscopy (SEM) coupled with energy-dispersive X-ray spectrometry (EDX), N2 adsorption-desorption measurements (BET, BJH, t-plot measurements) and Fourier transform infrared (FTIR) spectroscopy equipped with attenuated total reflectance (ATR) arrangements. (author)

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

    Science.gov (United States)

    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.

  10. Remarkable catalytic properties of hierarchical zeolite-Beta in epoxide rearrangement reactions

    Czech Academy of Sciences Publication Activity Database

    García-Munoz, J.L.; Serrano, D. P.; Vicente, G.; Linares, M.; Vitvarová, Dana; Čejka, Jiří

    2015-01-01

    Roč. 243, APR 2015 (2015), s. 141-152 ISSN 0920-5861 R&D Projects: GA ČR GBP106/12/G015 Institutional support: RVO:61388955 Keywords : hierarchical zeolites * zeolite beta * hybridzeolitic - mesostructured materials Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 4.312, year: 2015

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

    Science.gov (United States)

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

    2016-09-28

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

  12. Structure sensitive reactions over Co, Fe and mixed metal clusters in zeolites. Annual technical progress report

    Energy Technology Data Exchange (ETDEWEB)

    Suib, S.L.

    1992-08-01

    Transient and steady state kinetic studies of structure sensitive reactions of cyclopropane (c-C{sub 3}H{sub 6}) and hydrogen over zeolites is the first area of this studied. Low level impurity Fe{sup 3+} ions in zeolites complicate interpretation of spectroscopic and catalytic studies of these systems. We focused our efforts on selectively substituting Fe{sup 3+} ions in the frameworks of various zeolites to understand their role in catalytic reactions such as with c-C{sub 3}H{sub 6} and H{sub 2}. These studies led to isomorphous substitution of other ions like B{sup 3+} and their use in isomerization of n-butenes to isobutylene. The third area of research involves the synthesis, characterization and catalysis of a new class of molecular sieve manganese oxide tunnel structure materials.

  13. Characterization of gallium-containing zeolites for catalytic applications

    Energy Technology Data Exchange (ETDEWEB)

    Garcia Sanchez, M.

    2003-12-08

    The present study considers the synthesis, characterization, and catalytic evaluation of extra-framework gallium-containing zeolites. We focus on modification of zeolites by chemical vapor deposition of trimethylgallium on HZSM-5 and Mordenite zeolites. Chapter 2 is dedicated to the chemisorption and stability of TMG on HZSM-5 and HMOR zeolites. The effect of silylation is also addressed. Some theoretical calculations are also shown in this study to support part of the experimental results. In Chapter 3, the effect of oxidation and reduction treatments on these catalysts is investigated by FTIR, ICP and multinuclei NMR. In Chapter 4, the oxidation state and Ga coordination obtained during and after thermal treatment with H2 and O2 is analysed by X-ray adsorption spectroscopy (XANES and EXAFS) and IR analysis of CO adsorption. These results allow a better understanding of the catalytic behaviour of Ga-containing zeolites catalyst. Chapter 5 consists of two parts: one discusses the H2 activation over Ga/HZSM5 and Ga/MOR catalysts by H2/D2 isotopic exchange reaction, and the second part deals with the aromatization of n-heptane over the same catalysts.

  14. Isobutane/2-butene alkylation with zeolite Y without BrÆnsted acidity

    OpenAIRE

    Rosenbach Jr,Nilton; Mota,Claudio J. A.

    2005-01-01

    Alkylation of isobutane with 2-butene was performed on metal-exchanged Y zeolites, using an alkylchloride as carbocation initiator. The results indicated that, compared with a protonic zeolite, the deactivation was significantly slower and the production of trimethylpentanes was higher on the metal-exchanged zeolites. The metal cations act as Lewis acids, interacting with the chloride initiating the carbocationic reactions. The results also support the view that protonic sites on the catalyst...

  15. Theoretical maximal storage of hydrogen in zeolitic frameworks.

    Science.gov (United States)

    Vitillo, Jenny G; Ricchiardi, Gabriele; Spoto, Giuseppe; Zecchina, Adriano

    2005-12-07

    Physisorption and encapsulation of molecular hydrogen in tailored microporous materials are two of the options for hydrogen storage. Among these materials, zeolites have been widely investigated. In these materials, the attained storage capacities vary widely with structure and composition, leading to the expectation that materials with improved binding sites, together with lighter frameworks, may represent efficient storage materials. In this work, we address the problem of the determination of the maximum amount of molecular hydrogen which could, in principle, be stored in a given zeolitic framework, as limited by the size, structure and flexibility of its pore system. To this end, the progressive filling with H2 of 12 purely siliceous models of common zeolite frameworks has been simulated by means of classical molecular mechanics. By monitoring the variation of cell parameters upon progressive filling of the pores, conclusions are drawn regarding the maximum storage capacity of each framework and, more generally, on framework flexibility. The flexible non-pentasils RHO, FAU, KFI, LTA and CHA display the highest maximal capacities, ranging between 2.86-2.65 mass%, well below the targets set for automotive applications but still in an interesting range. The predicted maximal storage capacities correlate well with experimental results obtained at low temperature. The technique is easily extendable to any other microporous structure, and it can provide a method for the screening of hypothetical new materials for hydrogen storage applications.

  16. Design and characterization of chitosan/zeolite composite films — Effect of zeolite type and zeolite dose on the film properties

    International Nuclear Information System (INIS)

    Barbosa, Gustavo P.; Debone, Henrique S.; Severino, Patrícia; Souto, Eliana B.; Silva, Classius F. da

    2016-01-01

    Chitosan films can be used as wound dressings for the treatment of chronic wounds and severe burns. The antimicrobial properties of these films may be enhanced by the addition of silver. Despite the antimicrobial activity of silver, several studies have reported the cytotoxicity as a factor limiting its biomedical applications. This problem may, however, be circumvented by the provision of sustained release of silver. Silver zeolites can be used as drug delivery platforms to extend the release of silver. The objective of this study was to evaluate the addition of clinoptilolite and A-type zeolites in chitosan films. Sodium zeolites were initially subjected to ion-exchange in a batch reactor. Films were prepared by casting technique using a 2% w/w chitosan solution and two zeolite doses (0.1 or 0.2% w/w). Films were characterized by thermal analysis, color analysis, scanning electron microscopy, X-ray diffraction, and water vapor permeation. The results showed that films present potential for application as dressing. The water vapor permeability is one of the main properties in wound dressings, the best results were obtained for A-type zeolite/chitosan films, which presented a brief reduction of this property in relation to zeolite-free chitosan film. On the other hand, the films containing clinoptilolite showed lower water vapor permeation, which may be also explained by the best distribution of the particles into the polymer which also promoted greater thermal resistance. - Highlights: • Zeolite/chitosan composite films were prepared by casting technique. • Micrographs showed slight difference according to the content and A-type zeolite. • The barrier properties of the films were suitable to the dressing application. • Film characterization suggested that zeolites interacted with the chitosan chain.

  17. Design and characterization of chitosan/zeolite composite films — Effect of zeolite type and zeolite dose on the film properties

    Energy Technology Data Exchange (ETDEWEB)

    Barbosa, Gustavo P.; Debone, Henrique S. [Instituto de Ciências Ambientais, Químicas e Farmacêuticas, Universidade Federal de São Paulo, Diadema (Brazil); Severino, Patrícia [Universidade Tiradentes, Instituto de Tecnologia e Pesquisa, Aracaju (Brazil); Souto, Eliana B. [Department of Pharmaceutical Technology, Faculty of Pharmacy, University of Coimbra (FFUC), Pólo das Ciências da Saúde, Azinhaga de Santa Comba, 3000-548, Coimbra (Portugal); Center for Neuroscience and Cell Biology & Institute for Biomedical Imaging and Life Sciences (CNC-IBILI), University of Coimbra, Pólo das Ciências da Saúde, Azinhaga de Santa Comba, 3000-548, Coimbra (Portugal); Silva, Classius F. da, E-mail: cfsilva@unifesp.br [Instituto de Ciências Ambientais, Químicas e Farmacêuticas, Universidade Federal de São Paulo, Diadema (Brazil)

    2016-03-01

    Chitosan films can be used as wound dressings for the treatment of chronic wounds and severe burns. The antimicrobial properties of these films may be enhanced by the addition of silver. Despite the antimicrobial activity of silver, several studies have reported the cytotoxicity as a factor limiting its biomedical applications. This problem may, however, be circumvented by the provision of sustained release of silver. Silver zeolites can be used as drug delivery platforms to extend the release of silver. The objective of this study was to evaluate the addition of clinoptilolite and A-type zeolites in chitosan films. Sodium zeolites were initially subjected to ion-exchange in a batch reactor. Films were prepared by casting technique using a 2% w/w chitosan solution and two zeolite doses (0.1 or 0.2% w/w). Films were characterized by thermal analysis, color analysis, scanning electron microscopy, X-ray diffraction, and water vapor permeation. The results showed that films present potential for application as dressing. The water vapor permeability is one of the main properties in wound dressings, the best results were obtained for A-type zeolite/chitosan films, which presented a brief reduction of this property in relation to zeolite-free chitosan film. On the other hand, the films containing clinoptilolite showed lower water vapor permeation, which may be also explained by the best distribution of the particles into the polymer which also promoted greater thermal resistance. - Highlights: • Zeolite/chitosan composite films were prepared by casting technique. • Micrographs showed slight difference according to the content and A-type zeolite. • The barrier properties of the films were suitable to the dressing application. • Film characterization suggested that zeolites interacted with the chitosan chain.

  18. The Effect of Ozone and Zeolite Concentration to the Performance of the Treatment of Wastewater Containing Heavy Metal Using Flotation Process

    Directory of Open Access Journals (Sweden)

    Eva Karamah

    2010-10-01

    Full Text Available Industrial wastewater which contains heavy metal cannot be disposed to the environment directly, due to its toxicity. In this research, separation of metal from wastewater was conducted by sorptive flotation method, using Lampung natural zeolite as bonding agent. The most common diffuser used in the flotation process is air or oxygen. In this research, ozone is used as diffuser because it is a stronger oxidant and more dissolvable in water than oxygen. Besides, ozone is a coagulant aid and disinfectant. With ozone as diffuser, it is expected that the process become faster with higher efficiency. This research was conducted to determine ozone effectiveness as diffuser, compared with other diffuser, and also to determine optimum concentration and effectiveness of zeolite in flotation of iron, nickel and copper. The research result shows that separation of iron with air diffuser is 90.8%, air-oxygen diffuser is 95.7%, air-ozone (from air diffuser is 99.7%, and air-ozone (from oxygen diffuser is 99.7%. Natural zeolite is effective as bonding agent with optimum concentration equal to 2 gram/liter, producing separation percentage for iron equal to 99.70%, copper equal to 88.98% and Nickel equal to 98.46%.

  19. Bacterial biofilm supported on granular activated carbon and on natural zeolites- an application to wastewater treatment

    OpenAIRE

    Lameiras, Sandra Raquel de Vasconcelos; Quintelas, C.; Tavares, M. T.

    2004-01-01

    The removal of many heavy metals from industrial wastewater is one of the most important environmental problems to be solved today. The retention of this contaminants by a biofilm supported on granular activated carbon or on natural zeolites is one of the promising technologies for the reduction of this problem, because it is cheap and it removes a broad range of substances, heavy metals and organic compounds. This study aims the development of a system of two mini-columns in series ...

  20. PILLARED ZEOLITES AMENDMENTS INFLUENCE FROM POLLUTED SOIL ON HEAVY METALS BIOACCUMULATION IN TOMATOES

    Directory of Open Access Journals (Sweden)

    SMARANDA MASU

    2007-05-01

    Full Text Available Due to anthropic activities, the presence of metals in polluted soils has effects on plants development and metals bioaccumulation into trophic levels. In this paper, were followed experiments regarding the tomatoes development into polluted soils with 43.4 – 58.4 mg Cd/kg d.s. and 500- 633 mg Pb/kg d.s. Nickel, zinc and copper content in soils are in the range of diffuse pollution values. Comparatively, an experiment was realized with polluted soils and amended with pillared zeolites. Pillared zeolites change metals distribution in soil fractions and their solubility. Tomato plants grew onto polluted soils, but did not present fruits. Tomatoes from polluted and amended soils presented fruits and metals in tissues (Zn  Cu  Ni. Zinc concentration was five times greater then Ni. Fruits do not accumulate cadmium and lead.

  1. Zeolite function studied by neutron diffraction

    International Nuclear Information System (INIS)

    Newsam, J.M.

    1988-01-01

    Some recent figures relating to industrial uses of zeolites are summarized. Recent advances in the application of neutron diffraction to zeolite science are overviewed, with particular emphasis on powder diffraction (PND) results. Single crystal neutron diffraction studies of some 17 hydrated natural and synthetic zeolites have now appeared and they provide a consistent picture of zeolite-water interactions. Complete PND studies of hydrated synthetic ABW- and SOD-framework zeolites have also been reported. Other PND studies have explored the structural consequences of non-framework cation exchange, of framework modification by dealumination, and of framework cation substitution. Relatively simple zeolite-hydrocarbon sorbate complexes that have been studied include benzene in zeolite Y, and benzene and pyridine in zeolite L. Areas that are well poised for further development include further extensions to lower symmetry systems, the use of PND data for zeolite structure solution, studies at elevated temperatures and pressures, and further studies of zeolite sorbate complexes. (author) 68 refs., 7 figs

  2. Copper nitrate redispersion to arrive at highly active silica-supported copper catalysts

    NARCIS (Netherlands)

    Munnik, P.|info:eu-repo/dai/nl/328228524; Wolters, M.|info:eu-repo/dai/nl/304829560; Gabrielsson, A.; Pollington, S.D.; Headdock, G.; Bitter, J.H.|info:eu-repo/dai/nl/160581435; de Jongh, P.E.|info:eu-repo/dai/nl/186125372; de Jong, K.P.|info:eu-repo/dai/nl/06885580X

    2011-01-01

    In order to obtain copper catalysts with high dispersions at high copper loadings, the gas flow rate and gas composition was varied during calcination of silica gel impregnated with copper nitrate to a loading of 18 wt % of copper. Analysis by X-ray diffraction (XRD), N2O chemisorption, and

  3. Removal of paraquat solution onto zeolite material

    Science.gov (United States)

    Sirival, Rujikarn; Patdhanagul, Nopbhasinthu; Preecharram, Sutthidech; Photharin, Somkuan

    2018-04-01

    The purpose of this research was to study the adsorption of paraquat herbicides onto zeolite Y materials by the batch method. Three adsorbents material: Zeolite-3, Zeolite-10, and Zeolite-100 were Si/Al ratio at 3.58, 8.57 and 154.37, respectively. The factors for adsorption of paraquat as follows, adsorption time, initial concentrations of paraquat, pH and adsorption isotherm were investigated. The results showed that zeolite-10 had higher adsorption capacity than zeolite-3 and zeolite-100. The appropriate conditions for adsorption were 24 h., Zeolite 0.1 g., Initial paraquat concentration 100 ppm at pH 6. The adsorption isotherm was found to correspond with Langmuir Isotherm and the maximum paraquat adsorption is 26.38 mg/g for zeolite-10, 21.41 mg/g and 9.60 mg/g for zeolite-3 and zeolite-100, respectively. The characterization of zeolite material with XRD, XRF and BET. Furthermore, the zeolite materials applied to remove other organic and inorganic wastewater.

  4. {gamma} alumina- and HY zeolite-supported molybdenum catalysts: characterisation of the oxidic and sulfided phases; Catalyseurs a base de molybdene supporte sur alumine {gamma} et zeolithe HY: caracterisation des phases oxydes et sulfures

    Energy Technology Data Exchange (ETDEWEB)

    Plazenet, G

    2001-10-01

    Oxidic precursors of hydro-treatment catalysts (Co)Mo/alumina or zeolite were characterised by Raman spectroscopy, NMR and EXAFS at the Mo and Co K-edges. The formation of an Anderson-type alumino-molybdate compound upon impregnation of the support with an ammonium hepta-molybdate solution was confirmed for alumina, and also observed for the HY zeolitic support, with consumption of the amorphous alumina of the zeolite. In absence of the latter, ammonium hepta-molybdate precipitates. The species are conserved upon drying; upon calcination, the alumino-molybdate evolves into a surface aluminium molybdate type phase, whereas the hepta-molybdate transforms into MoO{sub 3}. The species formed upon impregnation are located in the inter-granular porosity whereas MoO{sub 3} vapor-condensation leads to formation of dimers located inside the zeolitic structure. The study of the cobalt-promoted precursors showed that the evolution of the molybdenum is the same in the case of co-impregnation preparation. Impregnation with cobalt-molybdate prevents the formation of the alumino-molybdate anion and thus enables the preservation of the Mo-Co interaction but, whatever the precursor, the leveling effect of the calcination-re-hydration steps was demonstrated. An EXAFS study at different sulfur coverages of the MoS{sub 2} platelets in the alumina-supported sulfided catalysts showed the limitations of EXAFS for size determination of MoS{sub 2} crystallites, a parameter that can be reached by AWAXS, which also conveys information about sheet-stacking. The EXAFS study of sulfided (Co)Mo/HY systems revealed incomplete sulfidation of the samples and the very high dispersion of the active phase. The absence of an observable Mo-Co interaction whatever the preparation of the promoted catalysts is consistent with the absence of promoting effect in toluene hydrogenation. (author)

  5. Hydrogenation of hexene over platinum on alumina vs. platinum in a Na-Y zeolite

    International Nuclear Information System (INIS)

    Miner, R.S. Jr.; Ione, K.G.; Namba, S.; Turkevich, J.

    1978-01-01

    In order to study the efficacy of zeolites as supports, several platinum H--Y zeolites were prepared by ion exchanging an H--Y zeolite with Pt(NH 3 ) 4 Cl 2 and reducing these products with hydrazine hydrate (A, B, C). Another preparation was made by adsorbing 32-A platinum sol on the zeolite crystallites (D). These catalysts were studied for hydrogenation and isomerization of hexene-1, ethylene hydrogenation, hydrogen chemisorption, and poison titration. They were compared with monodisperse Pt (32 A diameter) on alumina. A marked difference was found between the behavior of hexene-1 with the platinum-in-zeolite and with the platinum-on-alumina

  6. REMOVAL OF COPPER ELECTROLYTE CONTAMINANTS BY ADSORPTION

    Directory of Open Access Journals (Sweden)

    B Gabai

    1997-09-01

    Full Text Available Abstract - Selective adsorbents have become frequently used in industrial processes. Recent studies have shown the possibility of using adsorption to separate copper refinery electrolyte contaminants, with better results than those obtained with conventional techniques. During copper electrorefinning, many impurities may be found as dissolved metals present in the anode slime which forms on the electrode surface, accumulated in the electrolyte or incorporated into the refined copper on the cathode by deposition. In this study, synthetic zeolites, chelating resins and activated carbons were tested as adsorbents to select the best adsorbent performance, as well as the best operating temperature for the process. The experimental method applied was the finite bath, which consists in bringing the adsorbent into contact with a finite volume of electrolyte while controlling the temperature. The concentration of metals in the liquid phase was continuously monitored by atomic absorption spectrophotometry (AAS

  7. ADSORPSI POLUTAN ION DIKROMAT MENGGUNAKAN ZEOLIT ALAM TERMODIFIKASI AMINA (Adsorption of Dichromate Ions Pollutant Using Ammine Modified-Natural Zeolites

    Directory of Open Access Journals (Sweden)

    Eko Sri Kunarti

    2015-11-01

    Full Text Available ABSTRAK Kromium (VI merupakan polutan logam berat berbahaya bagi kesehatan dan lingkungan oleh karena itu pengambilan ion Cr(VI dalam air penting dilakukan untuk mengatasi pencemaran lingkungan. Proses adsorpsi merupakan salah satu teknik sederhana yang dapat digunakan untuk pengambilan ion logam. Pada penelitian ini telah dilakukan kajian adsorpsi ion dikromat sebagai model limbah Cr(VI dalam air menggunakan adsorben zeolit alam termodifikasi amina. Penelitian diawali dengan preparasi adsorben zeolit alam termodifikasi amina. Preparasi dimulai dengan pencucian zeolit alam menggunakan akuades, kemudian refluks zeolit alam menggunakan HCl 3M. Zeolit hasil refluks selanjutnya dimodifikasi menggunakan garam ammonium kuarterner, N-cethyl-N,N,N-trimethylammonium bromide (CTAB dan amina primer, propilamin (PA. Zeolit alam (Z, zeolit teraktivasi asam (ZA dan zeolit hasil modifikasi amina selanjutnya digunakan sebagai adsorben untuk adsorpsi anion dikromat. Karakterisasi adsorben dilakukan dengan mengunakan metode spektroskopi infaramerah dan difraksi sinar-X, sedangkan jumlah anion dikromat yang teradsorpsi dianalisis dengan spektroskopi serapan atom. Hasil penelitian menunjukkan bahwa sampel zeolit mengandung mineral klinoptilolit, mordernit dan kuarsa. Struktur zeolit tidak mengalami kerusakan oleh perlakuan termal dan perlakuan kimia. Modifikasi zeolit meningkatkan efisiensi adsorpsi zeolit alam. Ion dikromat dapat teradsorpsi dengan lebih baik oleh zeolit termodifikasi amina daripada zeolit teraktivasi asam dan zeolit tanpa modifikasi, dengan kemampuan adsorpsi zeolit termodifikasi CTAB (CTAB-Z lebih besar daripada zeolit termodifikasi propilamin (PA-Z. Adsorpsi ion dikromat pada adsorben zeolit berlangsung baik dengan urutan CTAB-Z > PA-Z > ZA > Z, dengan kemampuan adsorpsi masing-masing sebesar 1,96; 1,74; 0,90 dan 0,48 mg/g. Adsorpsi anion dikromat oleh zeolit termodifikasi CTAB merupakan adsorpsi kimia (kemisorpsi dengan energi adsorpsi sebesar

  8. Zeolites as catalyzer to environmental control. Nitric oxide removal

    International Nuclear Information System (INIS)

    Montes, C.; Zapata N, M; Villa H, A.L.

    1995-01-01

    Zeolites and the microporous materials related to them are a class of environmental catalysts, it which are used to remove the produced gases in combustion process (as mobile sources). In this work the importance that has catalysis for environment improvement is emphasized. A review of recent progress in the use of certain zeolitic material as catalysts for nitric oxide elimination of combustion systems is presented. More used nitric oxide removal methods are presented, as well as its advantages and disadvantages. Furthermore, it is emphasized on the need of accomplishing more investigation projects on the development of an active catalyst for the decomposition of the nitric oxide in its elements (N and O)

  9. Hydrothermally grown zeolite crystals

    International Nuclear Information System (INIS)

    Durrani, S.K.; Qureshi, A.H.; Hussain, M.A.; Qazi, N.K.

    2009-01-01

    The aluminium-deficient and ferrosilicate zeolite-type materials were synthesized by hydrothermal process at 150-170 degree C for various periods of time from the mixtures containing colloidal reactive silica, sodium aluminate, sodium hydroxide, iron nitrate and organic templates. Organic polycation templates were used as zeolite crystal shape modifiers to enhance relative growth rates. The template was almost completely removed from the zeolite specimens by calcination at 550 degree C for 8h in air. Simultaneous thermogravimetric (TG) and differential thermal analysis (DTA) was performed to study the removal of water molecules and the amount of organic template cations occluded inside the crystal pore of zeolite framework. The 12-13% weight loss in the range of (140-560 degree C) was associated with removal of the (C/sub 3/H/sub 7/)/sub 4/ N+ cation and water molecules. X-ray diffraction (XRD) analysis and scanning electron microscope (SEM) techniques were employed to study the structure, morphology and surface features of hydrothermally grown aluminium-deficient and ferrosilicate zeolite-type crystals. In order to elucidate the mode of zeolite crystallization the crystallinity and unit cell parameters of the materials were determined by XRD, which are the function of Al and Fe contents of zeolites. (author)

  10. Mesoporous Zeolite Single Crystals for Catalytic Hydrocarbon Conversion

    DEFF Research Database (Denmark)

    Schmidt, I.; Christensen, Claus H.; Kustova, Marina

    2005-01-01

    Recently, mesoporous zeolite single crystals were discovered. They constitute a novel family of materials that features a combined micropore and mesopore architecture within each individual crystal. Here, we briefly summarize recent catalytic results from cracking and isomerization of alkalies......, alkylation of aromatics and present new results on isomerization of aromatics. Specifically, the shape-selective isomerization of meta-xylenc into para-xylene and ortho-xylene is studied. In all these reactions, rnesoporous zeolite single crystals prove to be unique catalysts since they provide easy...... transport to and from active sites and at the same time maintain the shape-selectivity required. Thus, all these results support the idea that the beneficial effect of the mesopores system in the mesoporous zeolite single crystals call be solely attributed to enhanced mass transport....

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

    Energy Technology Data Exchange (ETDEWEB)

    Salim, Mashitah Mad; Malek, Nik Ahmad Nizam Nik, E-mail: niknizam@fbb.utm.my

    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, 5 h) and this material has excellent performance as an antibacterial agent after silver ions loading. - Highlights: • Thermal treatment was used to regenerate surfactant modified zeolite. • The regenerated NaY zeolite formed was added with different silver loadings. • Regenerated AgY zeolite was tested for antibacterial activity on E. coli and S. aureus. • The antibacterial activity increased with increased of the amount of silver loadings. • The zeolite structure did not change with thermal and modification

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

    International Nuclear Information System (INIS)

    Salim, Mashitah Mad; Malek, Nik Ahmad Nizam Nik

    2016-01-01

    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, 5 h) and this material has excellent performance as an antibacterial agent after silver ions loading. - Highlights: • Thermal treatment was used to regenerate surfactant modified zeolite. • The regenerated NaY zeolite formed was added with different silver loadings. • Regenerated AgY zeolite was tested for antibacterial activity on E. coli and S. aureus. • The antibacterial activity increased with increased of the amount of silver loadings. • The zeolite structure did not change with thermal and modification

  13. Ultrasound-assisted dealumination of zeolite Y

    Indian Academy of Sciences (India)

    zeolite Y the Si/Al molar ratio plays an important role in solid acidity .... determined using electron microprobe X-ray analysis. (EMPA) We also ... Surface area (m2/g) Pore Volume (cm3/g) XRD calculation .... for financial support for this work.

  14. Risk assessment for the transportation of radioactive zeolite liners

    International Nuclear Information System (INIS)

    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: 90 Sr = 3000 Ci, 134 Cs = 7000 Ci, 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

  15. Rapid synthesis of beta zeolites

    Science.gov (United States)

    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.

  16. Copper recovery in a bench-scale carrier facilitated tubular supported liquid membrane system

    Directory of Open Access Journals (Sweden)

    Makaka S.

    2010-01-01

    Full Text Available The extraction of copper ions in a tubular supported liquid membrane using LIX 984NC as a mobile carrier was studied, evaluating the effect of the feed characteristics (flowrate, density, viscosity on the feedside laminar layer of the membrane. A vertical countercurrent, double pipe perspex benchscale reactor consisting of a single hydrophobic PVDF tubular membrane mounted inside was used in all test work. The membrane was impregnated with LIX 984NC and became the support for this organic transport medium. Dilute Copper solution passed through the centre pipe and sulphuric acid as strippant passed through the shell side. Copper was successfully transported from the feedside to the stripside and from the data obtained, a relationship between Schmidt, Reynolds and Sherwood number was achieved of.

  17. Síntese da zeólita ZSM-5 e suas propriedades estruturais após troca iônica com cobre Synthesis of the ZSM-5 zeolite and its structural properties after copper ion-exchange

    Directory of Open Access Journals (Sweden)

    E. L. Foletto

    2000-12-01

    Full Text Available A zeólita ZSM-5 foi sintetizada utilizando sílica "Aerosil-Degussa -- 380 m²/g" como fonte de silício, em substituição ao trisilicato de sódio, que é normalmente utilizado na síntese dessa zeólita. Subseqüentemente, foi incorporado cobre à ZSM-5 através do método convencional de troca iônica. Técnicas de difração de raios X, microscopia eletrônica de varredura, área superficial e análise elementar por absorção atômica foram utilizadas para verificar a formação da zeólita sintetizada e suas propriedades após troca com cobre. Os resultados mostraram que houve a formação da ZSM-5 nas condições de síntese empregadas e que a amostra modificada pelo processo de troca manteve as propriedades da zeólita original.The ZSM-5 zeolite was synthesized using silica "Aerosil-Degussa -- 380 m²/g" as silicon source, in substitution to the sodium trisilicate, which is usually employed in the zeolite synthesis. Subsequently, the copper was incorporated to ZSM-5 by conventional ion-exchange method. X-ray diffraction, scanning electron microscopy, surface area and elemental analysis by atomic absorption have been used to verify ZSM-5 formation and its properties after copper exchange. The results presented ZSM-5 formation in the employed synthesis conditions. The ion-exchanged sample conserved the original ZSM-5 properties.

  18. Separation of BSA through FAU-type zeolite ceramic composite membrane formed on tubular ceramic support: Optimization of process parameters by hybrid response surface methodology and biobjective genetic algorithm.

    Science.gov (United States)

    Vinoth Kumar, R; Ganesh Moorthy, I; Pugazhenthi, G

    2017-08-09

    In this study, Faujasite (FAU) zeolite was coated on low-cost tubular ceramic support as a separating layer through hydrothermal route. The mixture of silicate and aluminate solutions was used to create a zeolitic separation layer on the support. The prepared zeolite ceramic composite membrane was characterized using X-ray powder diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), particle size distribution (PSD), field emission scanning electron microscopy (FESEM), and zeta potential measurements. The porosity of ceramic support (53%) was reduced by the deposition of FAU (43%) zeolite layer. The pore size and water permeability of the membrane were evaluated as 0.179 µm and 1.62 × 10 -7  m 3 /m 2  s kPa, respectively, which are lower than that of the support (pore size of 0.309 µm and water permeability of 5.93 × 10 -7  m 3 /m 2  s kPa). The permeate flux and rejection potential of the prepared membrane were evaluated by microfiltration of bovine serum albumin (BSA). To study the influences of three independent variables such as operating pressure (68.94-275.79 kPa), concentration of BSA (100-500 ppm), and solution pH (2-4) on permeate flux and percentage of rejection, the response surface methodology (RSM) was used. The predicted models for permeate flux and rejection were further subjected to biobjective genetic algorithm (GA). The hybrid RSM-GA approach resulted in a maximum permeate flux of 2.66 × 10 -5  m 3 /m 2  s and BSA rejection of 88.02%, at which the optimum conditions were attained as 100 ppm BSA concentration, 2 pH solution, and 275.79 kPa applied pressure. In addition, the separation efficiency was compared with other membranes applied for BSA separation to know the potential of the fabricated FAU zeolite ceramic composite membrane.

  19. UTL zeolite and the way beyond

    Czech Academy of Sciences Publication Activity Database

    Shvets, O. V.; Nachtigall, P.; Roth, Wieslaw Jerzy; Čejka, Jiří

    2013-01-01

    Roč. 182, DEC 2013 (2013), s. 229-238 ISSN 1387-1811 R&D Projects: GA ČR GBP106/12/G015 Institutional support: RVO:61388955 Keywords : zeolite UTL * synthesis * hydrolysis Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 3.209, year: 2013

  20. Synthesis of 4A zeolites from kaolin for obtaining 5A zeolites through ionic exchange for adsorption of arsenic

    International Nuclear Information System (INIS)

    Resmini Melo, Carolina; Gracher Riella, Humberto; Cabral Kuhnen, Nivaldo; Angioletto, Elidio; Melo, Aline Resmini; Bernardin, Adriano Michael; Rocha, Marcio Roberto da; Silva, Luciano da

    2012-01-01

    Highlights: ► We synthesize 4A zeolite from kaolin by hydrothermal reaction with sodium hydroxide. ► The 4A zeolite synthesized underwent ion exchange with calcium ions, with different parameters, to obtain 5A zeolites. ► The best 4A zeolite obtained was used as adsorbent material for arsenic ions. ► The results showed that the 5A zeolite material obtained is a good adsorber of heavy ions. - Abstract: The synthesis of adsorbing zeolite materials requires fine control of the processing variables. There are distinct process variable settings for obtaining specific desired types of zeolites. The intent of this study was to obtain 4A zeolites from kaolin in order to obtain 5A zeolites through ionic exchange with the previously synthesized zeolite. This zeolite 5A was used as an adsorbent for arsenic ions. The results obtained were satisfactory.

  1. Electrode-Modified Zeolites - Electrode Microstructures Contained in and on a Heterogeneous Catalyst

    Science.gov (United States)

    1988-07-15

    zeolite Type Y and Pt supported on gamma-alumina. The electrolytic response of zeolite-supported Pt in the absence of added electrolyte salt for water or...character of metals at sizes where’ bulk metallic properties may not be exhibited. Furthermore, electrolyses are now allowed using loadings of catalysts which...in water until the filtrate tested negatively for Cl with AgNO 3; PtY was then dried a- 135 C. Equilibrium exchnge occurs at these low weight

  2. Design and characterization of chitosan/zeolite composite films--Effect of zeolite type and zeolite dose on the film properties.

    Science.gov (United States)

    Barbosa, Gustavo P; Debone, Henrique S; Severino, Patrícia; Souto, Eliana B; da Silva, Classius F

    2016-03-01

    Chitosan films can be used as wound dressings for the treatment of chronic wounds and severe burns. The antimicrobial properties of these films may be enhanced by the addition of silver. Despite the antimicrobial activity of silver, several studies have reported the cytotoxicity as a factor limiting its biomedical applications. This problem may, however, be circumvented by the provision of sustained release of silver. Silver zeolites can be used as drug delivery platforms to extend the release of silver. The objective of this study was to evaluate the addition of clinoptilolite and A-type zeolites in chitosan films. Sodium zeolites were initially subjected to ion-exchange in a batch reactor. Films were prepared by casting technique using a 2% w/w chitosan solution and two zeolite doses (0.1 or 0.2% w/w). Films were characterized by thermal analysis, color analysis, scanning electron microscopy, X-ray diffraction, and water vapor permeation. The results showed that films present potential for application as dressing. The water vapor permeability is one of the main properties in wound dressings, the best results were obtained for A-type zeolite/chitosan films, which presented a brief reduction of this property in relation to zeolite-free chitosan film. On the other hand, the films containing clinoptilolite showed lower water vapor permeation, which may be also explained by the best distribution of the particles into the polymer which also promoted greater thermal resistance.

  3. Theoretical investigation of layered zeolite frameworks: Interaction between IPC-1P layers derived from zeolite UTL

    Czech Academy of Sciences Publication Activity Database

    Grajciar, L.; Bludský, Ota; Roth, Wieslaw Jerzy; Nachtigall, P.

    2013-01-01

    Roč. 204, Apr 15 (2013), s. 15-21 ISSN 0920-5861 R&D Projects: GA ČR GBP106/12/G015 Institutional support: RVO:61388963 ; RVO:61388955 Keywords : layered zeolites * density functional theory * hydrogen bonding * structure Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 3.309, year: 2013

  4. Hydrodeoxygenation of fatty acid esters catalyzed by Ni on nano-sized MFI type zeolites

    Energy Technology Data Exchange (ETDEWEB)

    Schreiber, Moritz W.; Rodriguez-Niño, Daniella; Gutiérrez, Oliver Y.; Lercher, Johannes A.

    2016-01-01

    The impact of support morphology and composition on the intrinsic activity of Ni supported on MFI-type zeolite was explored in the hydrodeoxygenation of methyl stearate, tristearate, and algae oil (mixture of triglycerides). The nano-sized structure of the support (self-pillared nanosheets) is beneficial for the activity of the catalysts. Higher Ni dispersion and concomitant higher reaction rates were obtained on nano-structured supports than on zeolite with conventional morphology. Rates normalized to accessible Ni atoms (TOF), however, varied little with support morphology. Acidity of the support increases the rate of Ni-catalyzed C-O hydrogenolysis per surface metal site.

  5. Selective methane chlorination to methyl chloride by zeolite Y-based catalysts

    Science.gov (United States)

    Joo, Hyeonho; Kim, Daeho; Lim, Kwang Soo; Choi, Yong Nam; Na, Kyungsu

    2018-03-01

    The CH4 chlorination over Y zeolites was investigated to produce CH3Cl in a high yield. Three different catalytic systems based on Y zeolite were tested for enhancement of CH4 conversion and CH3Cl selectivity: (i) HY zeolites in H+-form having various Si/Al ratios, (ii) Pt/HY zeolites supporting Pt metal nanoparticles, (iii) Pt/NaY zeolites in Na+-form supporting Pt metal nanoparticles. The reaction was carried out using the gas mixture of CH4 and Cl2 with the respective flow rates of 15 and 10 mL min-1 at 300-350 °C using a fixed-bed reactor under a continuous gas flow condition (gas hourly space velocity = 3000 mL g-1 h-1). Above the reaction temperature of 300 °C, the CH4 chlorination is spontaneous even in the absence of catalyst, achieving 23.6% of CH4 conversion with 73.4% of CH3Cl selectivity. Under sufficient supplement of thermal energy, Cl2 molecules can be dissociated to two chlorine radicals, which triggered the C-H bond activation of CH4 molecule and thereby various chlorinated methane products (i.e., CH3Cl, CH2Cl2, CHCl3, CCl4) could be produced. When the catalysts were used under the same reaction condition, enhancement in the CH4 conversion was observed. The Pt-free HY zeolite series with varied Si/Al ratios gave around 27% of CH4 conversion, but there was a slight decrease in CH3Cl selectivity with about 64%. Despite the difference in acidity of HY zeolites having different Si/Al ratios, no prominent effect of the Si/Al ratios on the catalytic performance was observed. This suggests that the catalytic contribution of HY zeolites under the present reaction condition is not strong enough to overcome the spontaneous CH4 chlorination. When the Pt/HY zeolite catalysts were used, the CH4 conversion reached further up to 30% but the CH3Cl selectivity decreased to 60%. Such an enhancement of CH4 conversion could be attributed to the strong catalytic activity of HY and Pt/HY zeolite catalysts. However, both catalysts induced the radical cleavage of Cl2

  6. Catalytic Fast Pyrolysis of Cellulose Using Nano Zeolite and Zeolite/Matrix Catalysts in a GC/Micro-Pyrolyzer.

    Science.gov (United States)

    Lee, Kyong-Hwan

    2016-05-01

    Cellulose, as a model compound of biomass, was catalyzed over zeolite (HY,.HZSM-5) and zeolite/matrix (HY/Clay, HM/Clay) in a GC/micro-pyrolyzer at 500 degrees C, to produce the valuable products. The catalysts used were pure zeolite and zeolite/matrix including 20 wt% matrix content, which were prepared into different particle sizes (average size; 0.1 mm, 1.6 mm) to study the effect of the particle size of the catalyst for the distribution of product yields. Catalytic pyrolysis had much more volatile products as light components and less content of sugars than pyrolysis only. This phenomenon was strongly influenced by the particle size of the catalyst in catalytic fast pyrolysis. Also, in zeolite and zeolite/matrix catalysts the zeolite type gave the dominant impact on the distribution of product yields.

  7. Thermal behavior of natural zeolites

    International Nuclear Information System (INIS)

    Bish, D.L.

    1993-01-01

    Thermal behavior of natural zeolites impacts their application and identification and varies significantly from zeolite to zeolite. Zeolites evolve H 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 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

  8. Zeolite Membrane Reactor for Water Gas Shift Reaction for Hydrogen Production

    Energy Technology Data Exchange (ETDEWEB)

    Lin, Jerry Y.S. [Arizona State Univ., Mesa, AZ (United States)

    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.

  9. Spin probes of chemistry in zeolites

    International Nuclear Information System (INIS)

    Werst, D.W.; Trifunac, A.D.

    1997-09-01

    Electron spin resonance (EPR) studies in zeolites are reviewed in which radiolysis was used to ionize the zeolite lattice, create reactive intermediates, spin label reaction products and to provide a window onto chemistry and transport of adsorbates and matrix control of chemistry. The review examines reactions of radical cations and the influence of the geometry constraints inside the zeolite, explores how zeolite model systems can be used to learn about energy and charge transfer in solids and illustrates the use of radiolysis and EPR for in situ spectroscopic studies of solid-acid catalysis. The various spin probes created inside the zeolite pores report on properties of the zeolites as well as shed light on radiolytic processes

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

    Science.gov (United States)

    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. Copyright © 2015 Elsevier B.V. All rights reserved.

  11. Separation of cesium and strontium with zeolites

    Energy Technology Data Exchange (ETDEWEB)

    Kanno, T; Hashimoto, H [Tohoku Univ., Sendai (Japan). Research Inst. of Mineral Dressing and Metallurgy

    1976-06-01

    The basic studies of separation of cesium and strontium were made with specimens of zeolite, which are synthetic zeolites A, X and Y; synthetic mordenite; natural mordenite; and clinoptilolite. Ammonium chloride was used as eluent, because it was considered to be a most appropriate eluent in alkaline chlorides. Cesium was easily eluted from the zeolites A and X by ammonium chloride solution, but it was difficult to elute from the synthetic mordenite, natural mordenite and clinoptilolite by ammonium chloride solution, but it was difficult to elute from the zeolites A and X. The zeolite Y is the only one zeolite among these zeolites from which both of cesium and strontium were easily eluted by ammonium chloride solution. Strontium could be separated from cesium with zeolites by formation of Sr-EDTA chelate at pH above 11. In this process, cesium was only exchanged in zeolite column, but strontium flow out from it.

  12. Separation of cesium and strontium with zeolites

    International Nuclear Information System (INIS)

    Kanno, Takuji; Hashimoto, Hiroyuki

    1976-01-01

    The basic studies of separation of cesium and strontium were made with specimens of zeolite, which are synthetic zeolites A, X and Y; synthetic mordenite; natural mordenite; and clinoptilolite. Ammonium chloride was used as eluent, because it was considered to be a most appropriate eluent in alkaline chlorides. Cesium was easily eluted from the zeolites A and X by ammonium chloride solution, but it was difficult to elute from the synthetic mordenite, natural mordenite and clinoptilolite by ammonium chloride solution, but it was difficult to elute from the zeolites A and X. The zeolite Y is the only one zeolite among these zeolites from which both of cesium and strontium were easily eluted by ammonium chloride solution. Strontium could be separated from cesium with zeolites by formation of Sr-EDTA chelate at pH above 11. In this process, cesium was only exchanged in zeolite column, but strontium flow out from it. (auth.)

  13. Synthesis and Characterization of Zeolite Na−Y and Its Conversion to the Solid Acid Zeolite H−Y

    DEFF Research Database (Denmark)

    Warner, Terence Edwin; Galsgaard Klokker, Mads; Nielsen, Ulla Gro

    2017-01-01

    Zeolite Y has an iconic crystal structure, but more importantly, the hydrogen modification zeolite H−Y is the classic example of a solid acid which is used extensively as a catalyst in the oil industry. This metastable compound cannot be synthesized directly, which creates an opportunity to discuss...... various preparative strategies with the students, such as the three-stage procedure described here. Stage I concerns the hydrothermal synthesis of zeolite Na−Y, followed by ion-exchange with an ammonium acetate solution to form zeolite NH4−Y, and the latter is subsequently converted to zeolite H......−Y by thermolysis. Stages II and III may instead be performed using commercially available zeolites, Na−Y and NH4−Y, respectively, which shifts the learning objectives to structural characterization of zeolites. The characterization of the product and intermediate materials gives the students a practical insight...

  14. Removal of pyridine and quinoline by bio-zeolite composed of mixed degrading bacteria and modified zeolite

    International Nuclear Information System (INIS)

    Bai Yaohui; Sun Qinghua; Xing Rui; Wen Donghui; Tang Xiaoyan

    2010-01-01

    In the process of the biodegradation of pyridine and quinoline, ammonium is often generated because of the transformation of N from pyridine and quinoline. Zeolite has been proven to be an effective sorbent for the removal of the ammonium. The natural zeolite can be modified to be the macroporous carrier in the biological wastewater treatment process. In this study, a specific bio-zeolite composed of mixed bacteria (a pyridine-degrading bacterium and a quinoline-degrading bacterium) and modified zeolite was used for biodegradation and adsorption in two types of wastewater: sterile synthetic and coking wastewater. The experimental results indicated that pyridine and quinoline could be degraded simultaneously by the mixed bacteria. Furthermore, NH 4 + -N transformed from pyridine and quinoline could be removed by the modified zeolite. In addition, the bacterial community structures of the coking wastewater and the bio-zeolite were monitored by the amplicon length heterogeneity polymerase-chain reaction (LH-PCR) technique. Both LH-PCR results and scanning electron microscope (SEM) observations indicated that the microorganisms, including BW001 and BW003, could be easily attached on the surface of the modified zeolite and that the bio-zeolite could be used in the treatment of wastewater containing pyridine and/or quinoline.

  15. Catalysis with hierarchical zeolites

    DEFF Research Database (Denmark)

    Holm, Martin Spangsberg; Taarning, Esben; Egeblad, Kresten

    2011-01-01

    Hierarchical (or mesoporous) zeolites have attracted significant attention during the first decade of the 21st century, and so far this interest continues to increase. There have already been several reviews giving detailed accounts of the developments emphasizing different aspects of this research...... topic. Until now, the main reason for developing hierarchical zeolites has been to achieve heterogeneous catalysts with improved performance but this particular facet has not yet been reviewed in detail. Thus, the present paper summaries and categorizes the catalytic studies utilizing hierarchical...... zeolites that have been reported hitherto. Prototypical examples from some of the different categories of catalytic reactions that have been studied using hierarchical zeolite catalysts are highlighted. This clearly illustrates the different ways that improved performance can be achieved with this family...

  16. The role of zeolite in the Fischer–Tropsch synthesis over cobalt–zeolite catalysts

    International Nuclear Information System (INIS)

    Sineva, L V; Mordkovich, V Z; Asalieva, E Yu

    2015-01-01

    The review deals with the specifics of the Fischer–Tropsch synthesis for the one-stage syncrude production from CO and H 2 in the presence of cobalt–zeolite catalytic systems. Different types of bifunctional catalysts (hybrid, composite) combining a Fischer–Tropsch catalyst and zeolite are reviewed. Special attention focuses on the mechanisms of transformations of hydrocarbons produced in the Fischer–Tropsch process on zeolite acid sites under the synthesis conditions. The bibliography includes 142 references

  17. Characterization of Zeolite in Zeolite-Geopolymer Hybrid Bulk Materials Derived from Kaolinitic Clays

    Directory of Open Access Journals (Sweden)

    Hayami Takeda

    2013-05-01

    Full Text Available Zeolite-geopolymer hybrid materials have been formed when kaolin was used as a starting material. Their characteristics are of interest because they can have a wide pore size distribution with micro- and meso-pores due to the zeolite and geopolymer, respectively. In this study, Zeolite-geopolymer hybrid bulk materials were fabricated using four kinds of kaolinitic clays (a halloysite and three kinds of kaolinite. The kaolinitic clays were first calcined at 700 °C for 3 h to transform into the amorphous aluminosilicate phases. Alkali-activation treatment of the metakaolin yielded bulk materials with different amounts and types of zeolite and different compressive strength. This study investigated the effects of the initial kaolinitic clays on the amount and types of zeolite in the resultant geopolymers as well as the strength of the bulk materials. The kaolinitic clays and their metakaolin were characterized by XRD analysis, chemical composition, crystallite size, 29Si and 27Al MAS NMR analysis, and specific surface area measurements. The correlation between the amount of zeolite formed and the compressive strength of the resultant hybrid bulk materials, previously reported by other researchers was not positively observed. In the studied systems, the effects of Si/Al and crystalline size were observed. When the atomic ratio of Si/Al in the starting kaolinitic clays increased, the compressive strength of the hybrid bulk materials increased. The crystallite size of the zeolite in the hybrid bulk materials increased with decreasing compressive strength of the hybrid bulk materials.

  18. Detergent zeolite filtration plant

    OpenAIRE

    Stanković Mirjana S.; Pezo Lato L.

    2003-01-01

    The IGPC Engineering Department designed basic projects for detergent zeolite filtration plant, using technology developed in the IGPC laboratories. Several projects were completed: technological, machine, electrical, automation. On the basis of these projects, a production plant with a capacity of 75,000 t/y was manufactured, at "Zeolite Mira", Mira (VE), Italy, in 1997, for increasing detergent zeolite production, from 50,000 to 100,000 t/y. The main goal was to increase the detergent zeoli...

  19. Supported Metal Zeolites as Environmental Catalysts for Reduction of NOx Molecules

    International Nuclear Information System (INIS)

    May Nwe Win; Tin Tin Aye; Kyaw Myo Naing; Nyunt Wynn; Maung Maung Htay

    2005-09-01

    The NOx contamination of air is a major pollutant due to its reaction with the volatile organic compounds, which give rise to ground level (tropospheric) ozone. It is a conventional fact that NOx are one of the major components of car exhaust. In view of that fact, to sustain the tropospheric ozone is to reduce the amount of NOx in the air. Therefore, this paper is concerned with the catalytic activity of Fe-loaded zeolite and Cu-loaded zeolite used to decompose NIOx by SCR (selective catalytic reduction) reaction with very high activity have been studied. Their preparations, characterization by XRD, FT-IR and SEM were also studied. Fe and Cu containig were prepared by soild state ion-exchange method under ambient presure and at the temperature of 600C for 4 hours. From this study, selective catalytic reduction rection was observed, showing about 87% conversion of the NOx molecule with the corresponding optimum amount of catalyst (1.0+-0.5)g working under the reactor space volume of 30cm3 at ambient temperature (30-32)C

  20. Synthesis of Zeolite from Fly Ash and Removal of Heavy Metal Ions from Newly Synthesized Zeolite

    OpenAIRE

    Solanki, Parag; Gupta, Vikal; Kulshrestha, Ruchi

    2010-01-01

    Coal fly ash was used to synthesize X-type zeolite by alkali fusion followed by hydrothermal treatment. Characteristics of the various Fly ash samples were carried out. Coal proximate analysis was done. Batch experiment was carried out for the adsorption of some heavy metal ions on to synthesized Zeolite. The cost of synthesized zeolite was estimated to be almost one-fifth of that of commercial 13X zeolite available in the market.

  1. Zeolites - a high resolution electron microscopy study

    International Nuclear Information System (INIS)

    Alfredsson, V.

    1994-10-01

    High resolution transmission electron microscopy (HRTEM) has been used to investigate a number of zeolites (EMT, FAU, LTL, MFI and MOR) and a member of the mesoporous M41S family. The electron optical artefact, manifested as a dark spot in the projected centre of the large zeolite channels, caused by insufficient transfer of certain reflections in the objective lens has been explained. The artefact severely hinders observation of materials confined in the zeolite channels and cavities. It is shown how to circumvent the artefact problem and how to image confined materials in spite of disturbance caused by the artefact. Image processing by means of a Wiener filter has been applied for removal of the artefact. The detailed surface structure of FAU has been investigated. Comparison of experimental micrographs with images simulated using different surface models indicates that the surface can be terminated in different ways depending on synthesis methods. The dealuminated form of FAU (USY) is covered by an amorphous region. Platinum incorporated in FAU has a preponderance to aggregate in the (111) twin planes, probably due to a local difference in cage structure with more spacious cages. It is shown that platinum is intra-zeolitic as opposed to being located on the external surface of the zeolite crystal. This could be deduced from tomography of ultra-thin sections among observations. HRTEM studies of the mesoporous MCM-41 show that the pores have a hexagonal shape and also supports the mechanistic model proposed which involves a cooperative formation of a mesophase including the silicate species as well as the surfactant. 66 refs, 24 figs

  2. Effect of different glasses in glass bonded zeolite

    International Nuclear Information System (INIS)

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

    1995-01-01

    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

  3. Avaliação e remoção de cobre em aguardentes de cana pela utilização dos aluminossilicatos: zeólita e bentonita Evaluation and removal of sugar cane brandy using aluminossilicates: zeolite and bentonite

    Directory of Open Access Journals (Sweden)

    Fabiane de Oliveira Cantão

    2010-10-01

    Full Text Available A cachaça, bebida genuinamente nacional, é um produto de grande aceitação nos mercados interno e externo. Durante o processo de produção há alguns pontos críticos, ocorrendo a formação de contaminantes que podem afetar a qualidade da bebida, sendo necessário o conhecimento de sua composição química. Com este trabalho, objetivou-se comparar o comportamento do cobre, quando presente em solução alcoólica 40% e uma aguardente comercial (utilizando sulfato de cobre pentaidratado como fonte desse mesmo metal, além de avaliar a remoção de cobre na bebida, utilizando dois aluminossilicatos (zeólita e bentonita comumente empregados na adsorção de metais. A zeólita e bentonita adsorveram mais cobre quando estiveram presentes em solução alcoólica do que em aguardente. Esses resultados sugerem que o cobre em aguardente deva estar ligado a moléculas volumosas, dificultando sua entrada nos pequenos poros da argila bentonita e da zeólita ZSM-5. Quando os aluminossilicatos estiveram presentes na aguardente impregnada com cobre em alambique, a bentonita foi mais eficiente na remoção do cobre do que a zeólita; no entanto a zeólita é mais recomendada na remoção do cobre, pois a redução das concentrações dos componentes secundários foi menor, não descaracterizando a bebida.The "cachaça", a genuinely national drink, is a product of great acceptance in the domestic and international markets. Therefore, we need to know its chemical composition, as in the production process a few critical points due to the presence of contaminants that can affect the quality of the drink. This work is aimed to compare the behaviour of copper, when present in a 40% alcohol solution and a "cachaça" trade (using copper sulfate pentahydrate as a source of the same metal, in addition to evaluating the removal of copper in the spirit, using two aluminosilikate (zeolite and bentonite commonly employed in the adsorption of metals. The zeolite and

  4. Two-Dimensional Zeolites: Current Status and Perspectives

    Czech Academy of Sciences Publication Activity Database

    Roth, Wieslaw Jerzy; Nachtigall, P.; Morris, R. E.; Čejka, Jiří

    2014-01-01

    Roč. 114, č. 9 (2014), s. 4807-4837 ISSN 0009-2665 R&D Projects: GA ČR GBP106/12/G015 Institutional support: RVO:61388955 Keywords : zeolites * mesoporous molecular sieves * Fischer-Tropsch synthesis Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 46.568, year: 2014

  5. Removal of pyridine from liquid and gas phase by copper forms of natural and synthetic zeolites

    Czech Academy of Sciences Publication Activity Database

    Reháková, M.; Fortunová, L.; Bastl, Zdeněk; Nagyová, S.; Dolinská, S.; Jorík, V.; Jóna, E.

    2011-01-01

    Roč. 186, č. 1 (2011), s. 699-706 ISSN 0304-3894 R&D Projects: GA AV ČR KAN100400702 Institutional research plan: CEZ:AV0Z40400503 Keywords : natural zeolite * clinoptilolite * ZSM5 Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 4.173, year: 2011

  6. Zeolite Encapsulated Nanocrystalline CuO: A Redox Catalyst for the Oxidation of Secondary Alcohols

    Directory of Open Access Journals (Sweden)

    Sakthivel Vijaikumar

    2008-01-01

    Full Text Available Zeolite encapsulated nanocrystalline CuO is synthesized and characterized by powder XRD and HRTEM analyses which clearly show that the particles are less than 15 nm and the nanoparticles are highly dispersed. This nano CuO encapsulated CuY zeolite is used as catalyst in the oxidation of aromatic secondary alcohols. CuY zeolite acts as an efficient support for nano CuO, by stabilizing it and preventing its aggregation. Plausible mechanisms for the formation of the various products are also given.

  7. Kinetic Adsorption Study of Silver Nanoparticles on Natural Zeolite: Experimental and Theoretical Models

    Directory of Open Access Journals (Sweden)

    Alvaro Ruíz-Baltazar

    2015-12-01

    Full Text Available In this research, the adsorption capacity of Ag nanoparticles on natural zeolite from Oaxaca is presented. In order to describe the adsorption mechanism of silver nanoparticles on zeolite, experimental adsorption models for Ag ions and Ag nanoparticles were carried out. These experimental data obtained by the atomic absorption spectrophotometry technique were compared with theoretical models such as Lagergren first-order, pseudo-second-order, Elovich, and intraparticle diffusion. Correlation factors R2 of the order of 0.99 were observed. Analysis by transmission electron microscopy describes the distribution of the silver nanoparticles on the zeolite outer surface. Additionally, a chemical characterization of the material was carried out through a dilution process with lithium metaborate. An average value of 9.3 in the Si/Al ratio was observed. Factors such as the adsorption behavior of the silver ions and the Si/Al ratio of the zeolite are very important to support the theoretical models and establish the adsorption mechanism of Ag nanoparticles on natural zeolite.

  8. Zeolite ZSM-57

    International Nuclear Information System (INIS)

    Valyocsik, E.W.; Page, N.M.; Chu, C.T.W.

    1989-01-01

    This patent describes a synthetic porous crystalline zeolite having a molar ratio of XO 2 ; Y 2 O 3 of at least 4. Wherein X represents silicon and/or germanium and Y represents aluminum, boron, chromium, iron and/or gallium. The porous crystalline zeolite having at least the X-ray diffraction lines as set forth in the text

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

    Science.gov (United States)

    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. Copyright © 2014 Elsevier B.V. All rights reserved.

  10. Synthesis of LTA zeolite on corundum supports: Preliminary assessment for heavy metal removal from waste water

    International Nuclear Information System (INIS)

    Jacas, A.; Ortega, P.; Velasco, M. J.; Camblor, M. A.; Rodriguez, M. A.

    2012-01-01

    The effectiveness of materials based on LTA Zeolite as active phase, for their incorporation into systems aimed at the removal of heavy metals on waste water is evaluated in a preliminary way. This type of Zeolite with the main channel of a minimum free diameter of 0,41 nm and a low SiO 2 /Al 2 O 3 ratio is an interesting molecular sieve, which in turn display a high ion exchange capacity. From this point of view, LTA Zeolite crystals were obtained in situ by hydrothermal synthesis and characterized by x ray diffraction (XRD) and scanning electron microscopy (SEM). We have studied the effect of hydrothermal synthesis time at 378 K. Likewise, the removal capacity of heavy metal from the active phase was evaluated in as a first step on diluted solutions of cooper salts at slightly acidic pH (∼ 4,7). (Author) 28 refs.

  11. Incorporation of metals (Pt-Ni-Ru) in the zeolite ZSM-5 through ion exchange competitive: synthesis and characterization

    International Nuclear Information System (INIS)

    Barbosa, A.S.; Rodrigues, M.G.F.

    2012-01-01

    Zeolites are very important materials due to their high specific surface area. Moreover, they are suitable for use as catalyst support. Noble metals supported on zeolites have been widely used as catalysts in the petrochemical industry. This paper was prepared and characterized, a powder aiming its use in heterogeneous catalysis. Support was used as ZSM-5 and the method of incorporation of the metals (Ru-PtNi) was competitive ion exchange. The materials (ZSM-5 and Pt-Ni-Ru/ZSM-5) were characterized by spectrophotometry Energy Dispersive X-ray (EDX), X-Ray Diffraction (XRD) and nitrogen physisorption (BET method). Based on the results of X-ray diffraction, it is possible to demonstrate the preservation of the structure of zeolite ZSM-5 after the competitive ion Exchange with metals (Ru-Pt-Ni) and calcination. The dispersion of metals on ZSM-5 did not change the textural characteristics of the zeolite. (author)

  12. Energetics of sodium-calcium exchanged zeolite A.

    Science.gov (United States)

    Sun, H; Wu, D; Guo, X; Shen, B; Navrotsky, A

    2015-05-07

    A series of calcium-exchanged zeolite A samples with different degrees of exchange were prepared. They were characterized by powder X-ray diffraction (XRD) and differential scanning calorimetry (DSC). High temperature oxide melt drop solution calorimetry measured the formation enthalpies of hydrated zeolites CaNa-A from constituent oxides. The water content is a linear function of the degree of exchange, ranging from 20.54% for Na-A to 23.77% for 97.9% CaNa-A. The enthalpies of formation (from oxides) at 25 °C are -74.50 ± 1.21 kJ mol(-1) TO2 for hydrated zeolite Na-A and -30.79 ± 1.64 kJ mol(-1) TO2 for hydrated zeolite 97.9% CaNa-A. Dehydration enthalpies obtained from differential scanning calorimetry are 32.0 kJ mol(-1) H2O for hydrated zeolite Na-A and 20.5 kJ mol(-1) H2O for hydrated zeolite 97.9% CaNa-A. Enthalpies of formation of Ca-exchanged zeolites A are less exothermic than for zeolite Na-A. A linear relationship between the formation enthalpy and the extent of calcium substitution was observed. The energetic effect of Ca-exchange on zeolite A is discussed with an emphasis on the complex interactions between the zeolite framework, cations, and water.

  13. Biodiesel synthesis via transesterification of lipid Chlorophyta cultivated in walne rich carbon medium using KOH/Zeolite catalyst

    Science.gov (United States)

    Dianursanti, Hayati, Siti Zahrotul; Putri, Dwini Normayulisa

    2017-11-01

    Microalgae from the Chlorophyta division such as Nannochloropsis oculata and Chlorella vulgaris are highly potential to be developed as biodiesel feedstocks because they have a high oil content up to 58%. Biodiesel is produced by transesterification of triglycerides and alcohols with the aid of homogeneous catalysts such as KOH. However, the use of KOH catalysts produces soaps in the biodiesel synthesis. Heterogeneous catalysts are known to solve this problem. One of them is natural zeolite. Zeolite can be used as a catalyst and as a support catalyst. Loading KOH on the zeolite surface is expected to increase alkalinity in KOH/Zeolite catalysts so as to increase the activity of KOH/Zeolite catalyst in transesterification of triglyceride with methanol. In this experimental lipid of microalgae will be used for produced biodiesel via transesterification reaction with methanol and KOH/Zeolite as a catalyst heterogeneous at 60 °C for 3h and utilized catalyst modificated KOH/Zeolite with variation 0.5 M, 1 M and 1.5 M KOH. The modified zeolite was then analyzed by XRF, XRD and BET. The result showed that the yield of biodiesel from lipid N.oculata was 81,09% by 0.5KOH/Zeolite catalyst, 86,53% by 1KOH/Zeolite catalyst, 1,5KOH/Zeolite and 88,13% by 1.5KOH/Zeolit, while the biodiesel produced from lipid C.vulgaris was 59.29% by 0.5KOH/Zeolite, 82.27% by 1KOH/Zeolite and 83.72% by 1.5KOH/Zeolite.

  14. A bioscaffolding strategy for hierarchical zeolites with a nanotube-trimodal network.

    Science.gov (United States)

    Li, Guannan; Huang, Haibo; Yu, Bowen; Wang, Yun; Tao, Jiawei; Wei, Yingxu; Li, Shougui; Liu, Zhongmin; Xu, Yan; Xu, Ruren

    2016-02-01

    Hierarchical zeolite monoliths with multimodal porosity are of paramount importance as they open up new horizons for advanced applications. So far, hierarchical zeolites based on nanotube scaffolds have never been reported. Inspired by the organization of biominerals, we have developed a novel precursor scaffolding-solid phase crystallization strategy for hierarchical zeolites with a unique nanotube scaffolding architecture and nanotube-trimodal network, where biomolecular self-assembly (BSA) provides a scaffolding blueprint. By vapor-treating Sil-1 seeded precursor scaffolds, zeolite MFI nanotube scaffolds are self-generated, during which evolution phenomena such as segmented voids and solid bridges are observed, in agreement with the Kirkendall effect in a solid-phase crystallization system. The nanotube walls are made of intergrown single crystals rendering good mechanical stability. The inner diameter of the nanotube is tunable between 30 and 90 nm by varying the thickness of the precursor layers. Macropores enclosed by cross-linked nanotubes can be modulated by the choice of BSA. Narrow mesopores are formed by intergrown nanocrystals. Hierarchical ZSM-5 monoliths with nanotube (90 nm), micropore (0.55 nm), mesopore (2 nm) and macropore (700 nm) exhibit superior catalytic performance in the methanol-to-hydrocarbon (MTH) conversion compared to conventional ZSM-5. BSA remains intact after crystallization, allowing a higher level of organization and functionalization of the zeolite nanotube scaffolds. The current work may afford a versatile strategy for hierarchical zeolite monoliths with nanotube scaffolding architectures and a nanotube-multimodal network leading to self-supporting and active zeolite catalysts, and for applications beyond.

  15. Ion-exchange properties of zeolite/glass hybrid materials

    International Nuclear Information System (INIS)

    Taira, Nobuyuki; Yoshida, Kohei; Fukushima, Takuya

    2017-01-01

    Hybrid materials were prepared from ground glass powder and various zeolites such as A-type, mordenite, X-type, and Y-type zeolites, and their ion removal effect was investigated. The hybrid materials of A-type, Y-type, and mordenite zeolites showed similar Sr"2"+ removal rates from aqueous solutions. The removal rate of Sr"2"+ ions increased as the amount of zeolite in the hybrid materials increased. Compared with other hybrid materials, the hybrid materials of X-type zeolite showed higher Sr"2"+ removal rates, especially for zeolite content greater than 25%. As the amount of X-type zeolite in the hybrid materials increased, the Sr"2"+ removal rate increased greatly, with a 100% removal rate when the content of X-type zeolite exceeded 62.5%. (author)

  16. Introduction to zeolite theory and modelling

    NARCIS (Netherlands)

    Santen, van R.A.; Graaf, van de B.; Smit, B.; Bekkum, van H.

    2001-01-01

    A review. Some of the recent advances in zeolite theory and modeling are present. In particular the current status of computational chem. in Bronsted acid zeolite catalysis, mol. dynamics simulations of mols. adsorbed in zeolites, and novel Monte Carlo technique are discussed to simulate the

  17. Isobutane/2-butene alkylation with zeolite Y without BrÆnsted acidity

    OpenAIRE

    Rosenbach Jr, Nilton; Mota, Claudio J. A.

    2005-01-01

    Alkylation of isobutane with 2-butene was performed on metal-exchanged Y zeolites, using an alkylchloride as carbocation initiator. The results indicated that, compared with a protonic zeolite, the deactivation was significantly slower and the production of trimethylpentanes was higher on the metal-exchanged zeolites. The metal cations act as Lewis acids, interacting with the chloride initiating the carbocationic reactions. The results also support the view that protonic sites on the catalyst...

  18. Producing zeolites from fly ash

    International Nuclear Information System (INIS)

    Rayalu, S.; Labhestwar, N.K.; Biniwale, R.B.; Udhoji, J.S.; Meshram, S.U.; Khanna, P.

    1998-01-01

    Fly ash has virtually become a menace of thermal power generation, leading to its devastating effects on the environment. Development of alternate methods of its disposal - especially those with recourse to recovery of valuable materials-has thus become imperative. This paper deals with the utilisation of fly ash for the production of high value-added products, viz., commercial grade zeolites. The physico-chemical and morphological characteristics of fly ash based Zeolite-A (FAZ-A) compares well with commercial Zeolite-A. High calcium binding capacity, appropriate particle/pore size and other detergency characteristics of FAZ-A brings forth its potential as a substitute for phosphatic detergent builder. The technology is extremely versatile, and other products like Zeolite-X, Zeolite-Y, sodalite and mordenite are also amenable for cost effective production with modifications in certain reaction parameters. Low temperature operations, ready availability of major raw materials, simplicity of process and recycling of unused reactants and process water are special features of the process. (author)

  19. Infrared study of the nature of the copper ion--alkyne bond in Y zeolite

    International Nuclear Information System (INIS)

    Pichat, P.

    1975-01-01

    The infrared spectra of acetylene, deuterated acetylene, propyne, and but-2-yne, chemisorbed in Cu, Na--Y zeolites, which have undergone various treatments, were studied. It is concluded that the OH groups interact only with the weakly absorbed molecules, the Cu + ions are not involved, the acetylenic hydrogen atoms do not take part in the bonding, the Cu 2+ ion--alkyne bone results mainly from π donation from the unsaturated hydrocarbon to the metallic ion. (auth)

  20. Human bile sorption by cancrinite-type zeolites

    International Nuclear Information System (INIS)

    Linares, Carlos F.; Colmenares, Maryi; Ocanto, Freddy; Valbuena, Oscar

    2009-01-01

    A nitrated cancrinite-type zeolite was synthesized from zeolite X, NaOH and NaNO 3 solutions under autogeneous pressure at 80 deg. C for 48 h. This zeolite was characterized by X-ray diffraction (XRD), FT-IR-spectroscopy, scanning electron microscopy (SEM) and BET surface area. XRD, SEM and FT-IR confirmed the presence of nitrated cancrinite-type zeolite without other collateral phases as sodalite. Then, this sodium zeolite was exchanged with potassium and calcium cations and finally, these modified zeolites were reacted with biliar solutions from human gallbladder. Several factors such as: mass of used cancrinite, nature of the exchanged cation and reaction time of the cancrinite-bile solution interactions were studied. The composition of bile solutions (bile acids, phospholipids and bilirubin) was analyzed before and after the cancrinite-bile solution reaction. Results showed that the components of the bile were notably reduced after the contact with solids. Ca-cancrinite, 120 min of reaction time and 500 mg of solids were the best conditions determined for the bile acid reduction in human bile. When the modified zeolites were compared with the commercial cholestyramine, it was found that zeolites were more active than the latter. These zeolites may be an alternative choice to diminish cholesterol levels in hypercholesterolemic patients

  1. Properties of glass-bonded zeolite monoliths

    International Nuclear Information System (INIS)

    Lewis, M.A.; Fischer, D.F.; Murphy, C.D.

    1994-01-01

    It has been shown that mineral waste forms can be used to immobilize waste salt generated during the pyrochemical processing of spent fuel from the Integral Fast Reactor (IFR). Solid, leach resistant monoliths were formed by hot-pressing mixtures of salt-occluded zeolite A powders and glass frit at 990 K and 28 MPa. Additional samples have now been fabricated and tested. Normalized release rates for all elements, including iodide and chloride, were less than 1 g/m 2 d in 28-day tests in deionized water and in brine at 363 K (90 degrees C). Preliminary results indicate that these rates fall with time with both leachants and that the zeolite phase in the glass-bonded zeolite does not function as an ion exchanger. Some material properties were measured. The Poisson ratio and Young's modulus were slightly smaller in glass-bonded zeolite than in borosilicate glass. Density depended on zeolite fraction. The glass-bonded zeolite represents a promising mineral waste form for IFR salt

  2. Copper laser diagnostics and kinetics support

    International Nuclear Information System (INIS)

    1981-12-01

    In the effort MSNW participated with the LINL copper-Vapor Laser Program by providing a useful plasma diagnostic for interpretation of Copper-vapor laser kinetics. MSNW developed and delivered a pulsed interferometric diagnostic package to LLNL. Moreover MSNW provided personal services at the request and direction of LLL in the implementation of the diagnostic and interpretation of the data

  3. Preparation and characterization of new zeolite membranes. Application to gaseous separation; Preparation et caracterisation de nouvelles membranes de zeolithe application a la separation gazeuse

    Energy Technology Data Exchange (ETDEWEB)

    Anstett, M.

    1996-11-25

    Zeolites are interesting for the preparation of inorganic membranes which could be used for the continuous separation of gas and liquids by gas permeation and pervaporation. Zeolites membranes are obtained by hydrothermal synthesis and are characterized by XRD, SEM, TDA, IR, chemical analysis, EPMA, NMR, MAS NMR and gas permeation. After some tests of preparation of zeolite CHA and MFI self supporting membranes, the work is turned towards the preparation of zeolite MFI membranes supported by porous disks or {alpha} alumina, glass and tubes of carbon covered with a thin layer or zirconium dioxide. It is shown that the characteristics of the support (reactivity, pores dimensions, ...) strongly influence the quality of the prepared membrane. Two originals preparation processes are finalized. For the alumina disks, a gel precursor of zeolite is firs formed at the surface of the support by immersing successively that support in two non miscible liquids before the crystallisation. The gel is then converted into the zeolite by contact with water vapor. The zeolite layer obtained is localized at the surface of the support and present not only at the outside but also at the inside of the support. The characteristics of the zeolite layer can be controlled and the method can be adapted to various porous supports. The membrane obtained is interesting for hydrocarbons separations, for example the separation of methane and isobutane. In the case of Vycor glass disks, the reactivity of the support is first enhanced by contact with saturated water vapour. The temperature of the synthesis is then chosen relatively low in order to limit the attack of the support. With that method, a basic solution can be used without degradation of the support.The basicity leads to the formation of little crystals whose assembling is compact and homogeneous. The membrane obtained is interesting for example for the separation of normal butane and isobutane. (author) 71 refs.

  4. Fabrication of 6FDA-durene membrane incorporated with zeolite T and aminosilane grafted zeolite T for CO2/CH4 separation

    Science.gov (United States)

    Jusoh, Norwahyu; Fong Yeong, Yin; Keong Lau, Kok; Shariff, Azmi Mohd

    2017-08-01

    In the present work, zeolite T and aminosilane grafted zeolite T are embedded into 6FDA-durene polyimide phase for the fabrication of mixed matrix membranes (MMMs). FESEM images demonstrated that the improvement of interfacial adhesion between zeolite and polymer phases in MMM loaded with aminosilane grafted zeolite T was not significant as compared to zeolite T/6FDA-durene MMM. From the gas permeation test, CO2/CH4 selectivity up to 26.4 was achieved using MMM containing aminosilane grafted zeolite T, while MMM loaded with ungrafted zeolite T showed CO2/CH4 selectivity of 19.1. In addition, MMM incorporated with aminosilane grafted zeolite T particles successfully lies on Robeson upper bound 2008, which makes it an attractive candidate for CO2/CH4 separation.

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

    Energy Technology Data Exchange (ETDEWEB)

    Alejandro, Serguei [Laboratorio de Tecnologías Limpias (F. Ingeniería), Universidad Católica de la Santísima Concepción, Alonso de Ribera 2850, Concepción (Chile); Núcleo de Energías Renovables (F. Ingeniería), Universidad Católica de Temuco, Rudecindo Ortega 02950, Temuco (Chile); Valdés, Héctor, E-mail: hvaldes@ucsc.cl [Laboratorio de Tecnologías Limpias (F. Ingeniería), Universidad Católica de la Santísima Concepción, Alonso de Ribera 2850, Concepción (Chile); Manéro, Marie-Hélène [Université de Toulouse (France); INPT, UPS (France); Laboratoire de Génie Chimique, 4, Allée Emile Monso, F–31030 Toulouse (France); CNRS (France); Laboratoire de Génie Chimique, F–31030 Toulouse (France); Zaror, Claudio A. [Departamento de Ingeniería Química (F. Ingeniería), Universidad de Concepción, Concepción, Correo 3, Casilla 160–C (Chile)

    2014-06-01

    Highlights: • Surface acidity of modified natural zeolite is related to its chemical reactivity. • Brønsted acid sites are associated to toluene adsorption. • Lewis acid sites could decompose ozone generating surface active oxygen species. • Infrared spectra evidence active atomic oxygen and oxidation by-product formation. • 2NH4Z1 sample shows the highest reactivity toward adsorbed toluene. - Abstract: 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 823 K 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 623 K, 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.

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

    International Nuclear Information System (INIS)

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

    2014-01-01

    Highlights: • Surface acidity of modified natural zeolite is related to its chemical reactivity. • Brønsted acid sites are associated to toluene adsorption. • Lewis acid sites could decompose ozone generating surface active oxygen species. • Infrared spectra evidence active atomic oxygen and oxidation by-product formation. • 2NH4Z1 sample shows the highest reactivity toward adsorbed toluene. - Abstract: 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 823 K 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 623 K, 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

  7. Zeolites in poultry and swine production

    Directory of Open Access Journals (Sweden)

    Aline Félix Schneider

    Full Text Available ABSTRACT: Zeolites are minerals that have intriguing properties such as water absorption, ion adsorption and cation exchange capacity. There are approximately 80 species of natural zeolites recognized and hundreds of artificial zeolites, which have been researched in several fields. Due to their chemical characteristics, zeolites have great potential for use in animal production, especially in poultry and swine farms, as food additives, litter amendment and treatment of residues, with direct and indirect effects on performance, yield and quality of carcass, ambience of farm sheds and reduction of environmental pollution.

  8. Aldol condensation of furfural and acetone on zeolites

    Czech Academy of Sciences Publication Activity Database

    Kikhtyanin, O.; Kelbichová, V.; Vitvarová, Dana; Kubů, Martin; Kubička, D.

    2014-01-01

    Roč. 227, MAY 2014 (2014), s. 154-162 ISSN 0920-5861 R&D Projects: GA ČR GBP106/12/G015 Institutional support: RVO:61388955 Keywords : aldol condensation * oligomerization * zeolites Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 3.893, year: 2014

  9. Regioselective nitration of aromatic substrates in zeolite cages

    Indian Academy of Sciences (India)

    Unknown

    ... mixture, responsible for the generation of large amounts of wastes, which ... benzene in gas phase over solid catalysts such as SiO2–Al2O3, supported ... selective nitration with a nitrogen dioxide-oxygen-zeolite H-β/HY as a solid inorganic.

  10. Characterization of Mexican zeolite minerals

    International Nuclear Information System (INIS)

    Jimenez C, M.J.

    2005-01-01

    50% of the Mexican territory is formed by volcanic sequences of the Pliocene type, which appear extensively in the northwest states (Sonora, Sinaloa, Chihuahua, Durango) and west of Mexico (Jalisco and Nayarit), in central Mexico (Zacatecas, Guanajuato, San Luis Potosi, Queretaro, Hidalgo) and south of Mexico (Guerrero, Oaxaca); therefore, it is to be expected that in our country big locations of natural zeolites exist in its majority of the clinoptilolite type. The present study was focused toward the characterization of two Mexican natural zeolite rocks presumably of the clinoptilolite and filipsite types, one of them comes from the state of Chihuahua and the other of a trader company of non metallic minerals, due that these materials are not characterized, its are not known their properties completely and therefore, the uses that can be given to these materials. In this investigation work it was carried out the characterization of two Mexican zeolite rocks, one coming from the Arroyo zone, municipality of La Haciendita, in the state of Chihuahua; and the other one was bought to a trader company of non metallic minerals. The two zeolites so much in their natural form as conditioned with sodium; they were characterized by means of X-ray diffraction, scanning electron microscopy of high vacuum and elementary microanalysis (EDS), surface area analysis (BET), thermal gravimetric analysis. To differentiate the heulandite crystalline phase of the other clinoptilolite rock, its were carried out thermal treatments. The quantification of Al, Na, Ca, K, Mg, Fe was carried out in solution, by means of atomic absorption spectroscopy and the quantity of Si was determined by gravimetry. The zeolite rocks presented for the major part the crystalline heulandite and clinoptilolite phases for the most part, and it was found that the zeolite coming from the state of Chihuahua possesses a bigger content of heulandite and the denominated filipsite it is really a zeolite

  11. Acidity in zeolite catalysis

    NARCIS (Netherlands)

    Santen, van R.A.; Gauw, de F.J.M.M.; Corma, A.; Melo, F.; Mendioroz, S.; Fierro, J.L.G.

    2000-01-01

    A review with 21 refs. is provided on our current understanding of the activation of hydrocarbons by protonic zeolites. One has to distinguish the proton affinity of a zeolite, measured in an equil. expt., from proton activation that dets. a kinetic catalytic result. The proton affinity depends on

  12. Zeolite Nanoparticles for Selective Sorption of Plasma Proteins.

    Science.gov (United States)

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

    2015-11-30

    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.

  13. Examination of zeolites by neutron reflection method

    International Nuclear Information System (INIS)

    Szegedi, S.; Varadi, M.; Boedy, Z.T.; Vas, L.

    1991-01-01

    Neutron reflection method has been used for the determination of zeolite content in minerals. The basis of this measurement is to observe the large difference between the water content of zeolite and that of other mineralic parts of the sample. The method suggested can be used in a zeolite mine for measuring the zeolite content continuously and controlling the quality of the end products. (author) 5 refs.; 3 figs.; 3 tabs

  14. Colloidal processing and CO_2-capture performance Al_2O_3-zeolite 13X composites

    International Nuclear Information System (INIS)

    Andersson, L.; Akhtar, F.; Ojuva, A.; Bergstroem, L.

    2012-01-01

    Hierarchically porous composites for CO_2-capture have been produced by coating the inner walls of foam-like macroporous alumina monoliths, produced by templated synthesis, with microporous zeolite 13X particles. Homogeneous and dense coatings of the particulate adsorbent were obtained when the impregnation process was performed at a pH above 9. At this pH-level the colloidally stable suspensions of the negatively charged zeolite 13X particles could fill all the voids of the highly connected pore space of the alumina supports and attach to the monolith walls, which had been pre-coated with poly(ethylene imine). A CO_2-uptake as high as 5 mmol CO_2/g zeolite 13X was achieved for alumina-zeolite 13X composites through minimisation of the added inorganic binder, kaolin, to only 3.0 wt% with respect to zeolite content, and through optimisation of the thermal treatment.

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

    International Nuclear Information System (INIS)

    Richardson, J.W. Jr.

    1996-01-01

    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

  16. The effect of pore size dimensions in isoreticular zeolites on carbon dioxide adsorption heats

    Czech Academy of Sciences Publication Activity Database

    Zukal, Arnošt; Shamzhy, Mariya; Kubů, Martin; Čejka, Jiří

    2018-01-01

    Roč. 24, MAR2018 (2018), s. 157-163 ISSN 2212-9820 R&D Projects: GA ČR GBP106/12/G015 EU Projects: European Commission(XE) 640979 - ShaleXenvironmenT Institutional support: RVO:61388955 Keywords : UTL zeolite * IPC-n zeolites * Carbon dioxide adsorption Subject RIV: CF - Physical ; Theoretical Chemistry OBOR OECD: Physical chemistry Impact factor: 4.292, year: 2016

  17. Cross flow ultrafiltration of Cr (VI) using MCM-41, MCM-48 and Faujasite (FAU) zeolite-ceramic composite membranes.

    Science.gov (United States)

    Basumatary, Ashim Kumar; Kumar, R Vinoth; Ghoshal, Aloke Kumar; Pugazhenthi, G

    2016-06-01

    This work describes the removal of Cr (VI) from aqueous solution in cross flow mode using MCM-41, MCM-48 and FAU zeolite membranes prepared on circular shaped porous ceramic support. Ceramic support was manufactured using locally available clay materials via a facile uni-axial compaction method followed by sintering process. A hydrothermal technique was employed for the deposition of zeolites on the ceramic support. The porosity of ceramic support (47%) is reduced by the formation of MCM-41 (23%), MCM-48 (22%) and FAU (33%) zeolite layers. The pore size of the MCM-41, MCM-48 and FAU membrane is found to be 0.173, 0.142, and 0.153 μm, respectively, which is lower than that of the support (1.0 μm). Cross flow ultrafiltration experiments of Cr (VI) were conducted at five different applied pressures (69-345 kPa) and three cross flow rates (1.11 × 10(-7) - 2.22 × 10(-7) m(3)/s). The filtration studies inferred that the performance of the fabricated zeolite composite membranes is optimum at the maximum applied pressure (345 kPa) and the highest rejection is obtained with the lowest cross flow rate (1.11 × 10(-7) m(3)/s) for all three zeolite membrane. The permeate flux of MCM-41, MCM-48 and FAU zeolite composite membranes are almost remained constant in the entire duration of the separation process. The highest removal of 82% is shown by FAU membrane, while MCM-41 and MCM-48 display 75% and 77% of Cr (VI) removal, respectively for the initial feed concentration of 1000 ppm with natural pH of the solution at an applied pressure of 345 kPa. Copyright © 2016 Elsevier Ltd. All rights reserved.

  18. Increased thermal conductivity monolithic zeolite structures

    Science.gov (United States)

    Klett, James; Klett, Lynn; Kaufman, Jonathan

    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. Effects of heating on salt-occluded zeolite

    International Nuclear Information System (INIS)

    Lewis, M.A.; Hash, M.C.; Pereira, C.; Ackerman, J.P.

    1996-01-01

    The electrometallurgical treatment of spent nuclear fuel generates a waste stream of fission products in the electrolyte, LiCl-KCl eutectic salt. Argonne National Laboratory is developing a mineral waste form for this waste stream. The waste form consists of a composite formed by hot pressing salt-occluded zeolite and a glass binder. Pressing conditions must be judiciously chosen. For a given pressure, increasing temperatures and hold times give denser products but the zeolite is frequently converted to sodalite. Reducing the temperature or hold time leads to a porous zeolite composite. Therefore, conditions that affect the thermal stability of salt-occluded zeolite both with and without glass are being investigated in an ongoing study. The parameters varied in this stage of the work were heating time, temperature, salt loading, and glass content. The heat-treated samples were examined primarily by X-ray diffraction. Large variations were found in the rate at which salt-occluded zeolite converted to other phases such as nepheline, salt, and sodalite. The products depended on the initial salt loading. Heating times required for these transitions depended on the procedure and temperature used to prepare the salt-occluded zeolite. Mixtures of glass and zeolite reacted much faster than the pure salt-occluded zeolite and were almost always converted to sodalite

  20. Exfoliation of two-dimensional zeolites in liquid polybutadienes

    KAUST Repository

    Sabnis, Sanket

    2017-06-16

    Layered zeolite precursors were successfully exfoliated by brief shearing or sonication with the assistance of commercially available telechelic liquid polybutadienes at room temperature. The exfoliated zeolite nanosheets can form a stable suspension in an organic solvent, providing exciting potential for the fabrication of zeolite membranes, composite materials and hierarchical zeolites.

  1. Nuclear waste treatment using Iranian natural zeolites

    International Nuclear Information System (INIS)

    Kazemian, H.; Ghannadi Maraghe, M.

    2001-01-01

    Full text: The zeolite researches in Iran is a relatively new subject which has started about 10 years ago. The motivation for this scientific and interesting field was provided after discovery of significant deposits of natural zeolites in different regions of Iran as well as further developments of research institutions and the national concern to environmental protection especially the wastewater clean-up in point of view of recycling of such waste water to compensate some needs to water in other utilizations. This paper intends to review and describes scientific researches which have done on using zeolites in the field of nuclear waste treatment in Iran to introduce the potential resources to the world in more details. Zeolite tuffs are widely distributed in huge deposits in different regions of Iran. So far, the clinoptilolite tuffs are the most abundant natural zeolite which exist with zeolite content of 65%- 95%. Nowadays several different types of Iranian natural zeolites are characterized in point of view of chemical composition, type of structure, chemical, thermal, and radiation resistance using different instrumental and classical methods such as; X-ray diffraction (XRD), X-ray fluoresce (XRF), thermal methods of analysis (TA), scanning electron microscopy (SEM), analytical chemistry and radioanalytical methods as well as different ion-exchange techniques (e.g.3-7). The ability of Iranian natural clinoptilolite for removal of some fission products from nuclear wastewaters have been investigated. The selectivity of all investigated zeolites toward radiocesium and radiostrontium have been promising (e.g. 8-10). The successful synthesize of P zeolite from Iranian clinoptilolite-reach tuffs under different conditions were performed. The compatibility of zeolites with glass and cement matrices, for final disposal of radwaste, as well as their selectivity toward most dangerous heat generating radionuclides (e.g. 137 Cs and 90 Sr) is very important in using

  2. Spontaneous dispersion of PdO onto acid sites of zeolites studied by in situ DXAFS

    CERN Document Server

    Okumura, K; Niwa, M; Yokota, S; Kato, K; Tanida, H; Uruga, T

    2003-01-01

    The generation of highly dispersed PdO over zeolite supports was studied using in situ energy-dispersive XAFS (DXAFS) technique. From the comparison with the Na-ZSM-5, it was found that the oxidation as well as the spontaneous dispersion of Pd was promoted through the interaction between PdO and acid sites of H-form zeolites. (author)

  3. New developments in zeolite science and technology

    International Nuclear Information System (INIS)

    Murakami, Y.

    1986-01-01

    The contributions in this volume introduce numerous new results and concepts. MAS-NMR has become a powerful tool in the structural analysis of zeolite, metallosilicate and aluminophosphate, enabling definition at the atomic level of the silicon and aluminum forming the zeolite framework. Detailed knowledge on the structure of natural zeolite has increased. Regarding synthesis, studies on the preparation of various metallosilicates, the role of various organic compounds at templates and the kinetics of crystallization and crystal growth are presented. Developments in zeolite catalysts focus not only on the solid-acid catalysts and the shape selective catalysts but on the bifunctional type catalysts as well. Catalyses by metallosilicates or silicoaluminophosphates are reported. Attempts to improve the catalytic performance by modification are presented. Effort is also being devoted to the analysis of adsorption state and diffusion in zeolites. Zeolite deposits of economic value are reported from several countries. (Auth.)

  4. PENJERAPAN P-KHLOROFENOL DALAM AIR LIMBAH DENGAN ZEOLIT (Adsorption of p-Chlorophenol from Wastewater using Zeolite

    Directory of Open Access Journals (Sweden)

    Sarto Sarto

    2007-07-01

    Full Text Available ABSTRAK Penelitian ini bertujuan untuk mempelajari kemampuan zeolit untuk menjerap p-khlorofenol dari limbah cair secara batch, pada suhu 30 °C dan tekanan 1 atmosfer. Hasil penelitian menunjukkan bahwa proses penjerapan mengikuti persamaan Freundlich dan bersifat reversibel sebagian. Nisbah kinerja desorbsi dan penjerapan adalah antara 31,85 % dan 49,36 %. Kemampuan zeolit untuk menjerap p-khlorofenol meningkat dengan semakin rendahnya pH. pada nilai pH 3,92, berat zeolit 30 g, dan konsentrasi awal p-khlorofenol 97,302 mg/L. Adapun jumlah p-khlorofenol yang terjerap adalah sebesar 8,319 mg/L.   ABSTRACT The aim of this research is to study the characteristics of zeolit to adsorb p-chlorophenol from wastewater in a batch reactor at 30 oC and atmospheric conditions. The experimental results show that the adsorbtion process is partially reversible and fits with Freundlich Equation. The ratio of  desorption and adsortion performance is between 31.85 % and 49.36 %.  The performance of zeolit to adsorb p-chlorophenol increases with decreasing pH. At  pH about 3.92, using 30 g zeolit and 97.302 mg  p-chlorophenol/L. The concentration of adsorbed p-chlorophenol is about 8.319 mg/L.

  5. Sulphide phases in Y zeolite for hydro-treatment reactions; Phase sulfures dans une zeolithe Y pour l'hydrotraitement

    Energy Technology Data Exchange (ETDEWEB)

    Leyrit, P

    1999-06-28

    Several types of single (Mo, Co, Pd, Pt) or binary (MoCo, PdCo, PtCo) sulphides phases supported on a HY zeolite were studied. The catalysts were first prepared and characterised in the oxide form. Their reactivity was then evaluated in toluene hydrogenation and 4.6-dimethyl-dibenzo-thiophene hydro-desulfurization reactions. Characterisation of sulphide phases supported on HY zeolite was carried out by elemental analysis, X-Ray Diffraction (XRD), Transmission Electron Microscopy and Scanning Transmission Electron Microscopy (STEM), Extended X-Ray Absorption Fine Structure (EXAFS) and Temperature Programmed Reduction coupled with HS analysis. The results show that. compared with alumina supported catalysts, zeolite used as a support enables extremely active catalysts to be obtained. It appears in particular that molybdenum sulphide phases inside the zeolite have a very high intrinsic activity at low molybdenum content. This activity is attributed to highly dispersed molybdenum sulphide phases differing from MoS{sub 2} slabs and probably present as clusters. The influence of cobalt depends of its concentration. Thus at low loadings cobalt has a strong negative effect. It has been shown, in the molybdenum case, that cobalt interaction leads to an increase in the sulphur content of the molybdenum phases. At higher cobalt loading, the formation of a mixed phase is possible but the degree of promotion remains limited. This work emphasises the advantages of using zeolite supported sulphide phases, and especially Mo and Pd phases, in the hydro-treatment reactions. It seems however that single phases present a greater interest than binary phases. (author)

  6. Metal immobilization in soils using synthetic zeolites

    NARCIS (Netherlands)

    Osté, L.A.; Lexmond, T.M.; Riemsdijk, van W.H.

    2002-01-01

    In situ immobilization of heavy metals in contaminated soils is a technique to improve soil quality. Synthetic zeolites are potentially useful additives to bind heavy metals. This study selected the most effective zeolite in cadmium and zinc binding out of six synthetic zeolites (mordenite-type,

  7. Silicalite-1 zeolite membranes on unmodified and modified surfaces

    Indian Academy of Sciences (India)

    Silicalite-1 zeolite membranes were prepared hydrothermally on the porous ceramic supports, both unmodified and modified with 3-aminopropyl triethoxysilane (APTES) as a coupling agent following ex situ (secondary) crystal growth process. The microstructure of the membranes was examined by scanning electron ...

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

    Science.gov (United States)

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

    2016-01-07

    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.

  9. Natural zeolites in diet or litter of broilers.

    Science.gov (United States)

    Schneider, A F; Almeida, D S De; Yuri, F M; Zimmermann, O F; Gerber, M W; Gewehr, C E

    2016-04-01

    This study aims to analyse the influence of adding natural zeolites (clinoptilolite) to the diet or litter of broilers and their effects on growth performance, carcass yield and litter quality. Three consecutive flocks of broilers were raised on the same sawdust litter, from d 1 to d 42 of age, and distributed in three treatments (control with no added zeolites, addition of 5 g/kg zeolite to diet and addition of 100 g/kg zeolites to litter). The addition of zeolites to the diet or litter did not affect growth performance or carcass yield. The addition of zeolites to the diet did not influence moisture content of the litter, ammonia volatilisation was reduced only in the first flock and pH of litter was reduced in the second and third flock. However, the addition of zeolites to the litter reduced moisture content, litter pH and ammonia volatilisation in all flocks analysed. The addition of 5 g/kg zeolite to the diet in three consecutive flocks was not effective in maintaining litter quality, whereas the addition of 100 g/kg natural zeolites to sawdust litter reduced litter moisture and ammonia volatilisation in three consecutive flocks raised on the same litter.

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

    Science.gov (United States)

    Hui, K S; Chao, C Y H

    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 degrees C), space velocity (8400-41 900 h(-1)), and methane concentration (0.5-3.2 vol %). At 500 degrees 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.

  11. Computational approach in zeolite science

    NARCIS (Netherlands)

    Pidko, E.A.; Santen, van R.A.; Chester, A.W.; Derouane, E.G.

    2009-01-01

    This chapter presents an overview of different computational methods and their application to various fields of zeolite chemistry. We will discuss static lattice methods based on interatomic potentials to predict zeolite structures and topologies, Monte Carlo simulations for the investigation of

  12. Alkali resistant Fe-zeolite catalysts for SCR of NO with NH3 in flue gases

    DEFF Research Database (Denmark)

    Putluru, Siva Sankar Reddy; Jensen, Anker Degn; Riisager, Anders

    2011-01-01

    . The effect of potassium doping on the acidic and redox properties of the Fe-zeolite catalysts were studied. The prepared catalysts showed high surface area and surface acidity. This is essential for increased alkali resistivity in comparison with conventional metal oxide supports like, e.g. TiO2 and ZrO2......, towards e.g. potassium salts in flue gases from biomass fired power plants. These properties allowed both undoped and potassium doped Fe-zeolite catalysts to posses high activity during the selective catalytic reduction (SCR) of NO with NH3. The extent of deactivation of the Fe-zeolite catalysts...

  13. Synthesis of mesoporous zeolite catalysts by in situ formation of carbon template over nickel nanoparticles

    DEFF Research Database (Denmark)

    Abildstrøm, Jacob Oskar; Kegnæs, Marina; Hytoft, Glen

    2016-01-01

    A novel synthesis procedure for the preparation of the hierarchical zeolite materials with MFI structure based on the carbon templating method with in situ generated carbon template is presented in this study. Through chemical vapour deposition of coke on nickel nanoparticles supported on silica...... oxide, a carbon-silica composite is obtained and exploited as a combined carbon template/silica source for zeolite synthesis. This approach has several advantages in comparison with conventional carbon templating methods, where relatively complicated preparative strategies involving multistep...... impregnation procedures and rather expensive chemicals are used. Removal of the carbon template by combustion results in zeolite single crystals with intracrystalline pore volumes between 0.28 and 0.48 cm3/g. The prepared zeolites are characterized by XRD, SEM, TEM and physisorption analysis. The isomerization...

  14. Kinetic Modelling of the Removal of Multiple Heavy Metallic Ions from Mine Waste by Natural Zeolite Sorption

    Directory of Open Access Journals (Sweden)

    Amanda L. Ciosek

    2017-07-01

    Full Text Available This study investigates the sorption of heavy metallic ions (HMIs, specifically lead (Pb2+, copper (Cu2+, iron (Fe3+, nickel (Ni2+ and zinc (Zn2+, by natural zeolite (clinoptilolite. These HMIs are combined in single-, dual-, triple-, and multi-component systems. The batch mode experiments consist of a total initial concentration of 10 meq/L normality for all systems, acidified to a pH of 2 by concentrated nitric (HNO3 acid. A zeolite dosage of 4 g per 100 mL of synthetic nitrate salt aqueous solution is applied, for a contact period of 5 to 180 min. Existing kinetic models on HMIs sorption are limited for multi-component system combinations. Therefore, this study conducts kinetic analysis by both reaction and diffusion models, to quantify the sorption process. The study concludes that the process correlates best with the pseudo-second-order (PSO kinetic model. In the multi-component system combining all five HMIs, the initial sorption rate and theoretical equilibrium capacity are determined as 0.0033 meq/g·min and 0.1159 meq/g, respectively. This provides significant insight into the mechanisms associated with the sorption process, as well as contributing to the assessment of natural zeolite as a sorbent material in its application in industrial wastewater treatment.

  15. The ADOR synthesis of new zeolites: In silico investigation

    Czech Academy of Sciences Publication Activity Database

    Trachta, Michal; Nachtigal, P.; Bludský, Ota

    2015-01-01

    Roč. 243, Apr (2015), s. 32-38 ISSN 0920-5861 R&D Projects: GA ČR GBP106/12/G015 Institutional support: RVO:61388963 Keywords : ADOR * DFT calculations * zeolites * synthesis Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 4.312, year: 2015

  16. Limestone and Zeolite as Alternative Media in Horizontal Subsurface Flow Constructed Wetlands: Laboratory-Scale Studies

    Science.gov (United States)

    Lizama, K.; Jaque, I.; Ayala, J.

    2016-12-01

    Arsenic is well known for its chronic toxicity. Millions of people around the world are currently at risk, drinking water with As concentrations above 10 ppb, the WHO drinking water guideline. Although different treatment options exist, they are often limited by elevated costs and maintenance requirements. Constructed wetlands are a natural water treatment system, capable to remove metals and metalloids -including As- via different physical, chemical and biological processes. The use of alternative supporting media to enhance As removal in subsurface flow wetlands has been recommended, but not sufficiently studied. Limestone and zeolite have been identified as effective supporting media in subsurface flow wetlands aiming As removal. However, there are still key aspects to be addressed, such as the implications of using these media, the speciation in the solid phase, the role of vegetation, etc. This study investigated the performance of limestone and zeolite in three types of experiments: batch, column and as main supporting media in a bench scale horizontal subsurface flow wetland system. Synthetic water resembling a contaminated river in Chile (As concentration=3 mg/L, Fe concentration= 100 mg/L, pH=2) was used in all experiments. In the batch experiments, the As concentration, the mass of media and the contact time were varied. The column system consisted of three limestone columns and three zeolite columns, operated under a hydraulic loading of 20 mm/d. The wetland system consisted of twelve PVC cells: six filled with zeolite and six with limestone. Phragmites australis were planted in three cells of each media type, as control cells. From the batch experiments, maximum As sorption capacities as indicated by Langmuir model were 1.3 mg/g for limestone and 0.17 mg/g for zeolite, at 18 h contact time and 6.3 g/L medium concentration. EDS and XPS analyses revealed that As and Fe were retained in zeolite at the end of the batch experiments. Zeolite and limestone

  17. A general method to incorporate metal nanoparticles in zeolites and zeotypes

    DEFF Research Database (Denmark)

    2015-01-01

    Disclosed herein is a method for producing a zeolite, zeolite-like or zeotype structure with selective formation of metal, metal oxide or metal sulphide nanoparticles and/or clusters inside the zeolite, zeolite-like or zeotype structure.......Disclosed herein is a method for producing a zeolite, zeolite-like or zeotype structure with selective formation of metal, metal oxide or metal sulphide nanoparticles and/or clusters inside the zeolite, zeolite-like or zeotype structure....

  18. Zeolite-derived hybrid materials with adjustable organic pillars

    Czech Academy of Sciences Publication Activity Database

    Opanasenko, Maksym; Shamzhy, Mariya; Yu, F.; Zhou, W.; Morris, R. E.; Čejka, Jiří

    2016-01-01

    Roč. 7, č. 6 (2016), s. 3589-3601 ISSN 2041-6520 R&D Projects: GA ČR GP13-17593P; GA ČR GBP106/12/G015 Institutional support: RVO:61388955 Keywords : zeolites * inorganic aluminosilicate * nanoporous materials Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 8.668, year: 2016

  19. Alkali-activated blast furnace slag-zeolite cements and concretes

    International Nuclear Information System (INIS)

    Rakhimov, R.; Rakhimova, N.

    2012-01-01

    The aim of this work has been the study of alkali-activated slag-zeolite cements and concretes based on them. Various compositions have been tested and some characteristics such as the compressive strength have been measured versus zeolite additions. A table lists the specific surface area and particle size distributions of different cements. The conclusions of the study are the following. First, alkali-activated slag cements and concretes based on them are effective for immobilization of radioactive wastes and the production of building structures, designed for high radiation load. Secondly, zeolite-containing mineral additions are able to increase the immobilization capacity and radiation resistance of alkali-activated blast furnace slag cements and concretes. Thirdly, the efficiency of different zeolite-containing additions - 10% to increase alkali-activated blast furnace slag-zeolite cement strength was established. It is with alkaline components of water-glass, sodium carbonate, sodium sulphate. Fourth, the effective way of introducing zeolite additions in alkali-activated blast furnace slag-zeolite cement is inter-grinding of the slag and addition. Increase in strength of alkali-activated blast furnace slag-zeolite cement stone is 40% higher than that of the stone of a mixture of separately milled components. Fifth, Alkali-activated blast furnace slag-zeolite cements with zeolite-containing additions with a compressive strength of 10.1 to 140 MPa; alkali-activated blast furnace slag-zeolite cements mortars with compressive strength from 35.2 to 97.7 MPa; alkali-activated blast furnace slag-zeolite cements concretes with compressive strength up to 84.5 MPa and frost resistant up to 800 cycles were obtained

  20. Effect of Ge/Si substitutions on the local geometry of Si framework sites in zeolites: A combined high resolutionsup29/supSi MAS NMR and DFT/MM study on zeolite Beta polymorph C (BEC)

    Czech Academy of Sciences Publication Activity Database

    Whittleton, Sarah R.; Vicente, A.; Fernandez, C.; Rastegar, Somayeh F.; Fishchuk, Anna V.; Sklenák, Štěpán

    2018-01-01

    Roč. 267, SEP 2018 (2018), s. 124-133 ISSN 1387-1811 R&D Projects: GA ČR(CZ) GA15-14007S Grant - others:Ga MŠk(CZ) LM2015070 Institutional support: RVO:61388955 Keywords : 29 Si MAS NMR * bec * Ge-zeolites * Germanoaluminosilicates * Zeolite Beta polymorph C Subject RIV: CF - Physical ; Theoretical Chemistry OBOR OECD: Physical chemistry Impact factor: 3.615, year: 2016

  1. Vitrification of highly-loaded SDS zeolites

    International Nuclear Information System (INIS)

    Siemens, D.H.; Bryan, G.H.; Knowlton, D.E.; Knox, C.A.

    1982-11-01

    Pacific Northwest Laboratory (PNL) is demonstrating a vitrification system designed for immobilization of highly loaded SDS zeolites. The Zeolite Vitrification Demonstration Project (ZVDP) utilizes an in-can melting process. All steps of the process have been demonstrated, from receipt of the liners through characterization of the vitrified product. The system has been tested with both nonradioactive and radioactive zeolite material. Additional high-radioactivity demonstrations are scheduled to begin in FY-83. 5 figures, 4 tables

  2. Chemical reactivity of cation-exchanged zeolites

    OpenAIRE

    Pidko, E.A.

    2008-01-01

    Zeolites modified with metal cations have been extensively studied during the last two decades because of their wide application in different technologically important fields such as catalysis, adsorption and gas separation. Contrary to the well-understood mechanisms of chemical reactions catalyzed by Brønsted acid sites in the hydrogen forms of zeolites, the nature of chemical reactivity, and related, the structure of the metal-containing ions in cation-exchanged zeolites remains the subject...

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

    Science.gov (United States)

    Ćiçek, 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.

  4. AKTIVASI ZEOLIT ALAM SEBAGAI ADSORBEN PADA ALAT PENGERING BERSUHU RENDAH

    Directory of Open Access Journals (Sweden)

    Laeli Kurniasari

    2012-04-01

    Full Text Available ACTIVATION OF NATURAL ZEOLITE AS AN ADSORBENT FOR LOW TEMPERATURE DRYING SYSTEM. Drying is one process which is used in many industries, especially in food product. The process usually still has low energy efficiency and can make food deterioration because of the usage of high temperature. One alternative in drying technology is the use of zeolite as a water vapor adsorbent. This kind of drying method make it possible to operate in lower temperature, hence it will be suitable for heat sensitive product. Natural zeolit can be one promising adsorbent since it is spreadly abundant in Indonesia. Natural zeolite must be activated first before used, in order to get zeolite with high adsorption capacity. Activation process in natural zeolite will change the Si/Al ratio, polarity, and affinity of zeolite toward water vapor and also increase the porosity. Activation of natural zeolite can be done with two methods, chemical activation use NaOH and physical activation use heat. In the activation using NaOH, natural zeolite is immersed with NaOH solution 0.5-2N in 2 hour with temperature range 60-900C. The process is continued with the drying of zeolite in oven with 1100C for 4 hours. While in heat treatment, zeolit is heated into 200-5000C in furnace for 2-5 hours. SEM analysis is used to compare the change in zeolite morphology before and after each treatment, while to know the adsorption capacity of zeolite, the analyses were done in many temperature and relative humidity. Result gives the best condition in NaOH activation is NaOH 1N and temperature 700C, with water vapor loading is 0.171 gr/gr adsorbent. In heat treatment, the best condition is 3000C and 3 hours with loading 0.137 gr water vapor/gr adsorbent.  Pengeringan merupakan salah satu proses yang banyak digunakan pada produk pangan. Proses ini umumnya menyebabkan kerusakan pada bahan pangan, disamping masih rendahnya efisiensi energi. Salah satu alternatif pada proses pengeringan yaitu

  5. Sulphide phases in Y zeolite for hydro-treatment reactions; Phase sulfures dans une zeolithe Y pour l'hydrotraitement

    Energy Technology Data Exchange (ETDEWEB)

    Leyrit, P.

    1999-06-28

    Several types of single (Mo, Co, Pd, Pt) or binary (MoCo, PdCo, PtCo) sulphides phases supported on a HY zeolite were studied. The catalysts were first prepared and characterised in the oxide form. Their reactivity was then evaluated in toluene hydrogenation and 4.6-dimethyl-dibenzo-thiophene hydro-desulfurization reactions. Characterisation of sulphide phases supported on HY zeolite was carried out by elemental analysis, X-Ray Diffraction (XRD), Transmission Electron Microscopy and Scanning Transmission Electron Microscopy (STEM), Extended X-Ray Absorption Fine Structure (EXAFS) and Temperature Programmed Reduction coupled with HS analysis. The results show that. compared with alumina supported catalysts, zeolite used as a support enables extremely active catalysts to be obtained. It appears in particular that molybdenum sulphide phases inside the zeolite have a very high intrinsic activity at low molybdenum content. This activity is attributed to highly dispersed molybdenum sulphide phases differing from MoS{sub 2} slabs and probably present as clusters. The influence of cobalt depends of its concentration. Thus at low loadings cobalt has a strong negative effect. It has been shown, in the molybdenum case, that cobalt interaction leads to an increase in the sulphur content of the molybdenum phases. At higher cobalt loading, the formation of a mixed phase is possible but the degree of promotion remains limited. This work emphasises the advantages of using zeolite supported sulphide phases, and especially Mo and Pd phases, in the hydro-treatment reactions. It seems however that single phases present a greater interest than binary phases. (author)

  6. Absorption behavior of iodine from molten salt mixture to zeolite

    International Nuclear Information System (INIS)

    Sugihara, Kei; Terai, Takayuki; Suzuki, Akihiro; Uozumi, Koichi; Tsukada, Takeshi; Koyama, Tadafumi

    2011-01-01

    Behavior of zeolite to absorb anion fission product (FP) elements in molten LiCl-KCl eutectic salt was studied using iodine. At first, zeolite-A was selected as the suitable type of zeolite among zeolite-A (powder), zeolite-X (powder and granule), and zeolite-Y (powder) through experiments to heat the zeolite together with LiCl-KCl-KI salt, respectively. As the next step, similar experiments to immerse zeolite-A in molten LiCl-KCl-KI salt containing various concentrations of iodine were performed. The affinity of iodine to zeolite was evaluated using the separation factor (SF) value, which is defined as [I/(I+Cl) mol ratio in zeolite after immersion]/[I/(I+Cl) mol ratio in salt after immersion]. Since the SF values ranged between 4.3 and 9.1, stronger affinity of iodine than chlorine to zeolite-A was revealed. Finally, influence of co-existing cation FPs was studied by similar absorption experiments in LiCl-KCl-KI salt containing CsCl, SrCl 2 , or NdCl 3 . The SF values were less than those obtained in the LiCl-KCl-KI salt and this can be ascribed to the sharing of inner space of zeolite cage among absorbed cations and anions. (author)

  7. THE EFFECT OF TYPE ZEOLITE ON THE GAS TRANSPORT PROPERTIES OF POLYIMIDE-BASED MIXED MATRIX MEMBRANES

    Directory of Open Access Journals (Sweden)

    Tutuk Djoko Kusworo

    2012-01-01

    Full Text Available The permeation rates of O2, N2, CO2 and CH4 has been studied for polyimide-polyethersulfone (PI/PES blends-zeolite mixed matrix membranes synthesized in our laboratory. The study investigated the effect of zeolite loading and different zeolite type on the gas separation performance of these mixed matrix membranes. Frequency shifts and absorption intensity changes in the FTIR spectra of the PI/PES blends as compared with those of the pure polymers indicate that there is a mixing of polymer blends at the molecular level. Differential scanning calorimetry measurements of pure and PI/PES blends membranes have showed one unique glass transition temperature that supports the miscible character of the PI/PES mixture. The PI/PES-zeolite 4A mixed matrix membrane with 25 wt % zeolite loading produced the highest O2/N2 and CO2/CH4 selectivity of around 7.45 and 46.05, respectively.

  8. Zircon Supported Copper Catalysts for the Steam Reforming of Methanol

    Science.gov (United States)

    Widiastri, M.; Fendy, Marsih, I. N.

    2008-03-01

    Steam reforming of methanol (SRM) is known as one of the most favorable catalytic processes for producing hydrogen. Current research on zirconia, ZrO2 supported copper catalyst revealed that CuO/ZrO2 as an active catalyst for the SRM. Zircon, ZrSiO4 is available from the by-product of tin mining. In the work presented here, the catalytic properties of CuO/ZrSiO4 with various copper oxide compositions ranging from 2.70% (catalyst I), 4.12% (catalyst II), and 7.12%-mass (catalyst III), synthesized by an incipient wetness impregnation technique, were investigated to methanol conversion, selectivity towards CO formation, and effect of ZnO addition (7.83%CuO/8.01%ZnO/ZrSiO4 = catalyst V). The catalytic activity was obtained using a fixed bed reactor and the zircon supported catalyst activity was compared to those of CuO/ZnO/Al2O3 catalyst (catalyst IV) and commercial Kujang LTSC catalyst. An X-ray powder diffraction (XRD) analysis was done to identify the abundant phases of the catalysts. The catalysts topography and particle diameter were measured with scanning electron microscopy (SEM) and composition of the catalysts was measured by SEM-EDX, scanning electron microscope-energy dispersive using X-ray analysis. The results of this research provide information on the possibility of using zircon (ZrSiO4) as solid support for SRM catalysts.

  9. Hydrogen Selective Exfoliated Zeolite Membranes

    Energy Technology Data Exchange (ETDEWEB)

    Tsapatsis, Michael [Univ. of Minnesota, Minneapolis, MN (United States). Department of Chemical Engineering and Materials Science; Daoutidis, Prodromos [Univ. of Minnesota, Minneapolis, MN (United States). Department of Chemical Engineering and Materials Science; Elyassi, Bahman [Univ. of Minnesota, Minneapolis, MN (United States). Department of Chemical Engineering and Materials Science; Lima, Fernando [Univ. of Minnesota, Minneapolis, MN (United States). Department of Chemical Engineering and Materials Science; Iyer, Aparna [Univ. of Minnesota, Minneapolis, MN (United States). Department of Chemical Engineering and Materials Science; Agrawal, Kumar [Univ. of Minnesota, Minneapolis, MN (United States). Department of Chemical Engineering and Materials Science; Sabnis, Sanket [Univ. of Minnesota, Minneapolis, MN (United States). Department of Chemical Engineering and Materials Science

    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

  10. ZEOLITIZATION OF SEWAGE SLUDGE ASH WITH A FUSION METHOD

    Directory of Open Access Journals (Sweden)

    Jolanta Latosińska

    2016-11-01

    Full Text Available The study shows the results of zeolitization of municipal sewage sludge ash with the indirect fusion method followed by a hydrothermal method. The zeolitization of sewage sludge ash was conducted at the melting temperature of 550°C and the melting time of 60 minutes, crystallization temperatures of 60°C and 90°C, crystallization time of 6 hours and the SSA:NaOH ratio of 1:1.8; 1:1.4. The research of modified sewage sludge ashes included the observation of changes of ash particles surface and the identification of crystalized phases. The zeolitization of sewage sludge ash at the ratio of SSA:NaOH 1.0:1.4 did not cause the formation of zeolite phases. On the other hand, the zeolitization at the ratio of SSA:NaOH 1.0:1.8 resulted in the formation of desired zeolite phases such as zeolite Y (faujasite and hydroxysodalite. The presented method of sewage sludge ash zeolitization allows to obtain highly usable material. Synthesized zeolites may be used as adsorbents and ion exchangers. They can be potentially used to remove heavy metals as well as ammonia from water and wastewater.

  11. Preparation of Synthetic Zeolites from Myanmar Clay Mineral

    International Nuclear Information System (INIS)

    Phyu Phyu Win

    2004-04-01

    Faujasite type zeolite X was successfully synthesized from Myanmar clay mineral kaolinite, by treating with sodium hydroxide at 820 C followed by dissolution in water and hydrothermal treatment. It was found that the solution of fused clay powder can be crystallized at 90C under ambient pressure to synthesize faujasite type zeolite X. The effects of aging time and the amount of water on the formation of the product phase and Si/ Al ratios of the resulting products were investigated. Most of the Si and Al components in kaolinite might be dissolved into an alkaline solution and reacted to form ring-like structures. Then it was effectively transformed into zeolite materials. The maximum relative crystallinity of faujasite zeolite obtained was found to be 100%. Zeolite P was found to be a competitive phase present in some resulting products during hydrothermal treatment. The cation exchange capacity of kaolinite is very low, but increased after a proper treatment. It was found that the prepared faujasite type zeolite X, zeolite P and hydrogen zeolite (HZ) can reduce the hardness, the alkalinity, the total dissolved solid and the dissolved iron of raw water in the batch wise operation of water treatment. Therefore, it can be used as the cation exchanged resin for water treatment

  12. Strong white photoluminescence from annealed zeolites

    International Nuclear Information System (INIS)

    Bai, Zhenhua; Fujii, Minoru; Imakita, Kenji; Hayashi, Shinji

    2014-01-01

    The optical properties of zeolites annealed at various temperatures are investigated for the first time. The annealed zeolites exhibit strong white photoluminescence (PL) under ultraviolet light excitation. With increasing annealing temperature, the emission intensity of annealed zeolites first increases and then decreases. At the same time, the PL peak red-shifts from 495 nm to 530 nm, and then returns to 500 nm. The strongest emission appears when the annealing temperature is 500 °C. The quantum yield of the sample is measured to be ∼10%. The PL lifetime monotonously increases from 223 μs to 251 μs with increasing annealing temperature. The origin of white PL is ascribed to oxygen vacancies formed during the annealing process. -- Highlights: • The optical properties of zeolites annealed at various temperatures are investigated. • The annealed zeolites exhibit strong white photoluminescence. • The maximum PL enhancement reaches as large as 62 times. • The lifetime shows little dependence on annealing temperature. • The origin of white emission is ascribed to the oxygen vacancies

  13. Reaction mechanisms in zeolite catalysis

    NARCIS (Netherlands)

    Rozanska, X.; Santen, van R.A.; Auerbach, S.C.; Carrado, K.A.; Dutta, P.D.

    2003-01-01

    A review; described are the most basic mechanistic reaction steps that are induced by zeolite catalysts. Details on the zeolitic properties that are relevant to mol. reactivity are also provided. The theor. methods and models at hand to allow the investigation of these reaction steps and that have

  14. Copper as a target for prostate cancer therapeutics: copper-ionophore pharmacology and altering systemic copper distribution

    Science.gov (United States)

    Denoyer, Delphine; Pearson, Helen B.; Clatworthy, Sharnel A.S.; Smith, Zoe M.; Francis, Paul S.; Llanos, Roxana M.; Volitakis, Irene; Phillips, Wayne A.; Meggyesy, Peter M.; Masaldan, Shashank; Cater, Michael A.

    2016-01-01

    Copper-ionophores that elevate intracellular bioavailable copper display significant therapeutic utility against prostate cancer cells in vitro and in TRAMP (Transgenic Adenocarcinoma of Mouse Prostate) mice. However, the pharmacological basis for their anticancer activity remains unclear, despite impending clinical trails. Herein we show that intracellular copper levels in prostate cancer, evaluated in vitro and across disease progression in TRAMP mice, were not correlative with copper-ionophore activity and mirrored the normal levels observed in patient prostatectomy tissues (Gleason Score 7 & 9). TRAMP adenocarcinoma cells harbored markedly elevated oxidative stress and diminished glutathione (GSH)-mediated antioxidant capacity, which together conferred selective sensitivity to prooxidant ionophoric copper. Copper-ionophore treatments [CuII(gtsm), disulfiram & clioquinol] generated toxic levels of reactive oxygen species (ROS) in TRAMP adenocarcinoma cells, but not in normal mouse prostate epithelial cells (PrECs). Our results provide a basis for the pharmacological activity of copper-ionophores and suggest they are amendable for treatment of patients with prostate cancer. Additionally, recent in vitro and mouse xenograft studies have suggested an increased copper requirement by prostate cancer cells. We demonstrated that prostate adenocarcinoma development in TRAMP mice requires a functional supply of copper and is significantly impeded by altered systemic copper distribution. The presence of a mutant copper-transporting Atp7b protein (tx mutation: A4066G/Met1356Val) in TRAMP mice changed copper-integration into serum and caused a remarkable reduction in prostate cancer burden (64% reduction) and disease severity (grade), abrogating adenocarcinoma development. Implications for current clinical trials are discussed. PMID:27175597

  15. Electrical conductivity of polyaniline/zeolite composites and synergetic interaction with CO

    International Nuclear Information System (INIS)

    Densakulprasert, Nataporn; Wannatong, Ladawan; Chotpattananont, Datchanee; Hiamtup, Piyanoot; Sirivat, Anuvat; Schwank, Johannes

    2005-01-01

    The effects of zeolite content, pore size and ion exchange capacity on electrical conductivity response to carbon monoxide (CO) of polyaniline/zeolite composites were investigated. Zeolite Y, 13X, and synthesized AlMCM41, all having the common cation Cu 2+ , were dry mixed with synthesized maleic acid (MA) doped polyaniline and compressed to form polyaniline (PANI)/zeolite pellet composites. The Y, 13X and AlMCM41 zeolite have the nominal pore sizes of 7, 10, 36 A, and the Cu 2+ exchange capacities of 0.161, 0.087, and 0.044 mol/g, respectively. With an addition of 13X zeolite to pristine polyaniline, the electrical conductivity sensitivity to CO/N 2 gas increases with zeolite content. For the effect of zeolite type, the highest electrical conductivity sensitivity is obtained with the 13X zeolite, followed by the Y zeolite, and the AlMCM41 zeolite, respectively. Poor sensitivity of zeolite AlMCM41 is probably due to its very large pore size and its lowest Cu 2+ exchange capacity. Y zeolite and 13X zeolite have comparable pore sizes but the latter has a greater pore free volume and a more favorable location distribution of the Cu 2+ ions within the pore. The temporal response time increases with the amount of zeolite in the composites but it is inversely related to the amount of ion exchange capacity

  16. Development of spent salt treatment technology by zeolite column system. Performance evaluation of zeolite column

    International Nuclear Information System (INIS)

    Miura, Hidenori; Uozumi, Koichi

    2009-01-01

    At electrorefining process, fission products(FPs) accumulate in molten salt. To avoid influence on heating control by decay heat and enlargement of FP amount in the recovered fuel, FP elements must be removed from the spent salt of the electrorefining process. For the removal of the FPs from the spent salt, we are investigating the availability of zeolite column system. For obtaining the basic data of the column system, such as flow property and ion-exchange performance while high temperature molten salt is passing through the column, and experimental apparatus equipped with fraction collector was developed. By using this apparatus, following results were obtained. 1) We cleared up the flow parameter of column system with zeolite powder, such as flow rate control by argon pressure. 2) Zeolite 4A in the column can absorb cesium that is one of the FP elements in molten salt. From these results, we got perspective on availability of the zeolite column system. (author)

  17. Zeolite food supplementation reduces abundance of enterobacteria.

    Science.gov (United States)

    Prasai, Tanka P; Walsh, Kerry B; Bhattarai, Surya P; Midmore, David J; Van, Thi T H; Moore, Robert J; Stanley, Dragana

    2017-01-01

    According to the World Health Organisation, antibiotics are rapidly losing potency in every country of the world. Poultry are currently perceived as a major source of pathogens and antimicrobial resistance. There is an urgent need for new and natural ways to control pathogens in poultry and humans alike. Porous, cation rich, aluminosilicate minerals, zeolites can be used as a feed additive in poultry rations, demonstrating multiple productivity benefits. Next generation sequencing of the 16S rRNA marker gene was used to phylogenetically characterize the fecal microbiota and thus investigate the ability and dose dependency of zeolite in terms of anti-pathogenic effects. A natural zeolite was used as a feed additive in laying hens at 1, 2, and 4% w/w for a 23 week period. At the end of this period cloacal swabs were collected to sample faecal microbial communities. A significant reduction in carriage of bacteria within the phylum Proteobacteria, especially in members of the pathogen-rich family Enterobacteriaceae, was noted across all three concentrations of zeolite. Zeolite supplementation of feed resulted in a reduction in the carriage of a number of poultry pathogens without disturbing beneficial bacteria. This effect was, in some phylotypes, correlated with the zeolite concentration. This result is relevant to zeolite feeding in other animal production systems, and for human pathogenesis. Copyright © 2016 Elsevier GmbH. All rights reserved.

  18. Natural zeolite reactivity towards ozone: The role of compensating cations

    International Nuclear Information System (INIS)

    Valdés, Héctor; Alejandro, Serguei; Zaror, Claudio A.

    2012-01-01

    Highlights: ► Chemical and thermal treatment enhances catalytic activity of natural zeolite. ► Modified natural zeolite exhibits high stability after thermal treatment. ► Reducing the compensating cation content leads to an increase on ozone abatement. ► Surface active atomic oxygen was detected using the DRIFT technique. ► The highest reactivity toward ozone was performed by NH4Z3 zeolite sample. - Abstract: Among indoor pollutants, ozone is recognised to pose a threat to human health. Recently, low cost natural zeolites have been applied as alternative materials for ozone abatement. In this work, the effect of compensating cation content of natural zeolite on ozone removal is studied. A Chilean natural zeolite is used here as starting material. The amount of compensating cations in the zeolite framework was modified by ion exchange using an ammonium sulphate solution (0.1 mol L −1 ). Characterisation of natural and modified zeolites were performed by X-ray powder diffraction (XRD), nitrogen adsorption at 77 K, elemental analysis, X-ray fluorescence (XRF), thermogravimetric analysis coupled with mass spectroscopy (TGA-MS), and temperature-programmed desorption of ammonia (NH 3 -TPD). Ozone adsorption and/or decomposition on natural and modified zeolites were studied by diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS). Results show that the zeolite compensating cation content affects ozone interaction with zeolite active sites. Ammonium ion-exchange treatments followed by thermal out-gassing at 823 K, reduces ozone diffusion resistance inside the zeolite framework, increasing ozone abatement on zeolite surface active sites. Weak and strong Lewis acid sites of zeolite surface are identified here as the main active sites responsible of ozone removal.

  19. Zeolitization at uranium ore manifestation

    International Nuclear Information System (INIS)

    Petrosyan, R.V.; Buntikova, A.F.

    1981-01-01

    The process of zeolitization at uranium ore manifestation is studied. A specific type of low-temperature wall endogenous alteration of rocks due to the effect of primary acid solution with low content of carbonic acid is established. Leaching of calcium from enclosing rocks and its deposition in ore-accompanying calcium zeolites is a characteristic feature of wall-metasomatosis. Formation of desmin- calcite-laumontite and quartz-fluoroapatite of vein associations, including ore minerals (uranophane and metaotenite), is genetically connected with calcium metasomatosis. On the basis of the connection of ore minerals with endogeneous process of zeolitization a conclusion can be made on endogenous origin of uranophane and metaotenite [ru

  20. Natural zeolite reactivity towards ozone: the role of compensating cations.

    Science.gov (United States)

    Valdés, Héctor; Alejandro, Serguei; Zaror, Claudio A

    2012-08-15

    Among indoor pollutants, ozone is recognised to pose a threat to human health. Recently, low cost natural zeolites have been applied as alternative materials for ozone abatement. In this work, the effect of compensating cation content of natural zeolite on ozone removal is studied. A Chilean natural zeolite is used here as starting material. The amount of compensating cations in the zeolite framework was modified by ion exchange using an ammonium sulphate solution (0.1 mol L(-1)). Characterisation of natural and modified zeolites were performed by X-ray powder diffraction (XRD), nitrogen adsorption at 77K, elemental analysis, X-ray fluorescence (XRF), thermogravimetric analysis coupled with mass spectroscopy (TGA-MS), and temperature-programmed desorption of ammonia (NH(3)-TPD). Ozone adsorption and/or decomposition on natural and modified zeolites were studied by diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS). Results show that the zeolite compensating cation content affects ozone interaction with zeolite active sites. Ammonium ion-exchange treatments followed by thermal out-gassing at 823 K, reduces ozone diffusion resistance inside the zeolite framework, increasing ozone abatement on zeolite surface active sites. Weak and strong Lewis acid sites of zeolite surface are identified here as the main active sites responsible of ozone removal. Copyright © 2012 Elsevier B.V. All rights reserved.

  1. Effect of SrO content on Zeolite Structure

    Science.gov (United States)

    Widiarti, N.; Sari, U. S.; Mahatmanti, F. W.; Harjito; Kurniawan, C.; Prasetyoko, D.; Suprapto

    2018-04-01

    The aims of current studies is to investigate the effect of strontium oxide content (SrO) on synthesized zeolite. Zeolite was synthesized from Tetraethyl orthosilicate (TEOS) as precursors of SiO2 and aluminum isopropoxide (AIP) precursors. The mixture was aged for 3 days and hydrothermally treated for 6 days. The SrO content was added by impregnation method. The products were then characterized using X-Ray Diffraction (XRD), Fourier Transform Infrared (FTIR), and Surface Area Analyzer (SAA). The diffractogram confirmed the formation of Faujasite-like zeolite. However, after the addition of SrO, the crystallinity of zeolite was deformed. The diffractograms shows the amorphous phase of zeolite were decrease as the SrO content is increase. The structural changes was also observed from FTIR spectra which shows the shifting and peak formation. The surface area analysis showed that the increasing loading of SrO/Zeolites reduced the catalyst surface area.

  2. Copper/MYC/CTR1 interplay: a dangerous relationship in hepatocellular carcinoma.

    Science.gov (United States)

    Porcu, Cristiana; Antonucci, Laura; Barbaro, Barbara; Illi, Barbara; Nasi, Sergio; Martini, Maurizio; Licata, Anna; Miele, Luca; Grieco, Antonio; Balsano, Clara

    2018-02-06

    Free serum copper correlates with tumor incidence and progression of human cancers, including hepatocellular carcinoma (HCC). Copper extracellular uptake is provided by the transporter CTR1, whose expression is regulated to avoid excessive intracellular copper entry. Inadequate copper serum concentration is involved in the pathogenesis of Non Alcoholic Fatty Liver Disease (NAFLD), which is becoming a major cause of liver damage progression and HCC incidence. Finally, MYC is over-expressed in most of HCCs and is a critical regulator of cellular growth, tumor invasion and metastasis. The purpose of our study was to understand if higher serum copper concentrations might be involved in the progression of NAFLD-cirrhosis toward-HCC. We investigated whether high exogenous copper levels sensitize liver cells to transformation and if it exists an interplay between copper-related proteins and MYC oncogene. NAFLD-cirrhotic patients were characterized by a statistical significant enhancement of serum copper levels, even more evident in HCC patients. We demonstrated that high extracellular copper concentrations increase cell growth, migration, and invasion of liver cancer cells by modulating MYC/CTR1 axis. We highlighted that MYC binds a specific region of the CTR1 promoter, regulating its transcription. Accordingly, CTR1 and MYC proteins expression were progressively up-regulated in liver tissues from NAFLD-cirrhotic to HCC patients. This work provides novel insights on the molecular mechanisms by which copper may favor the progression from cirrhosis to cancer. The Cu/MYC/CTR1 interplay opens a window to refine HCC diagnosis and design new combined therapies.

  3. Copper/MYC/CTR1 interplay: a dangerous relationship in hepatocellular carcinoma

    Science.gov (United States)

    Barbaro, Barbara; Illi, Barbara; Nasi, Sergio; Martini, Maurizio; Licata, Anna; Miele, Luca; Grieco, Antonio; Balsano, Clara

    2018-01-01

    Free serum copper correlates with tumor incidence and progression of human cancers, including hepatocellular carcinoma (HCC). Copper extracellular uptake is provided by the transporter CTR1, whose expression is regulated to avoid excessive intracellular copper entry. Inadequate copper serum concentration is involved in the pathogenesis of Non Alcoholic Fatty Liver Disease (NAFLD), which is becoming a major cause of liver damage progression and HCC incidence. Finally, MYC is over-expressed in most of HCCs and is a critical regulator of cellular growth, tumor invasion and metastasis. The purpose of our study was to understand if higher serum copper concentrations might be involved in the progression of NAFLD-cirrhosis toward-HCC. We investigated whether high exogenous copper levels sensitize liver cells to transformation and if it exists an interplay between copper-related proteins and MYC oncogene. NAFLD-cirrhotic patients were characterized by a statistical significant enhancement of serum copper levels, even more evident in HCC patients. We demonstrated that high extracellular copper concentrations increase cell growth, migration, and invasion of liver cancer cells by modulating MYC/CTR1 axis. We highlighted that MYC binds a specific region of the CTR1 promoter, regulating its transcription. Accordingly, CTR1 and MYC proteins expression were progressively up-regulated in liver tissues from NAFLD-cirrhotic to HCC patients. This work provides novel insights on the molecular mechanisms by which copper may favor the progression from cirrhosis to cancer. The Cu/MYC/CTR1 interplay opens a window to refine HCC diagnosis and design new combined therapies. PMID:29507693

  4. Zeolite and swine inoculum effect on poultry manure biomethanation

    DEFF Research Database (Denmark)

    Kougias, Panagiotis; Fotidis, Ioannis; Zaganas, I.D.

    2013-01-01

    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....

  5. Zeolite and swine inoculum effect on poultry manure biomethanation

    Science.gov (United States)

    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.

  6. Surfactant-directed mesoporous zeolites with enhanced catalytic activity in tetrahydropyranylation of alcohols: Effect of framework type and morphology

    Czech Academy of Sciences Publication Activity Database

    Shin, H. S.; Opanasenko, Maksym; Cabello, C. P.; Ryoo, R.; Čejka, Jiří

    2017-01-01

    Roč. 537, MAY 2017 (2017), s. 24-32 ISSN 0926-860X R&D Projects: GA ČR(CZ) GAP106/12/0189 Institutional support: RVO:61388955 Keywords : Nanosponge zeolite * Hierarchical zeolite * Tetrahydropyranylation Subject RIV: CF - Physical ; Theoretical Chemistry OBOR OECD: Physical chemistry Impact factor: 4.339, year: 2016

  7. Three Mile Island zeolite vitirification demonstration program

    International Nuclear Information System (INIS)

    Siemens, D.H.; Knowlton, D.E.; Shupe, M.W.

    1981-06-01

    The cleanup of the high-activity-level water at Three Mile Island (TMI) provides an opportunity to further develop waste management technology. Approximately 790,000 gallons of high-activity-level water at TMI's Unit-2 Nuclear Power Station will be decontaminated at the site using the submerged demineralizer system (SDS). In the SDS process, the cesium and strontium in the water are sorbed onto zeolite that is contained within metal liners. The Department of Energy has asked the Pacific Northwest Laboratory (PNL) to take a portion of the zeolite from the SDS process and demonstrate, on a production scale, that this zeolite can be vitrified using the in-can melting process. This paper is a brief overview of the TMI zeolite vitrification program. The first section discusses the formulation of a glass suitable for immobilizing SDS zeolite. The following section describes a feed system that was developed to feed zeolite to the in-can melter. It also describes the in-can melting process and the government owned facilities in which the demonstrations will take place. Finally, the schedule for completing the program activities is outlined

  8. Zeolites and Zeotypes for Oil and Gas Conversion

    NARCIS (Netherlands)

    Vogt, Eelco T C; Whiting, Gareth T.; Dutta Chowdhury, Abhishek; Weckhuysen, Bert M.

    2015-01-01

    Zeolite-based catalyst materials are widely used in chemical industry. In this chapter, the applications of zeolites and zeotypes in the catalytic conversion of oil and gas are reviewed. After a general introduction to zeolite science and technology, we discuss refinery applications, such as fluid

  9. Natural zeolite reactivity towards ozone: The role of compensating cations

    Energy Technology Data Exchange (ETDEWEB)

    Valdes, Hector, E-mail: hvaldes@ucsc.cl [Laboratorio de Tecnologias Limpias (F. Ingenieria), Universidad Catolica de la Santisima Concepcion, Alonso de Ribera 2850, Concepcion (Chile); Alejandro, Serguei; Zaror, Claudio A. [Departamento de Ingenieria Quimica (F. Ingenieria), Universidad de Concepcion, Concepcion (Chile)

    2012-08-15

    Highlights: Black-Right-Pointing-Pointer Chemical and thermal treatment enhances catalytic activity of natural zeolite. Black-Right-Pointing-Pointer Modified natural zeolite exhibits high stability after thermal treatment. Black-Right-Pointing-Pointer Reducing the compensating cation content leads to an increase on ozone abatement. Black-Right-Pointing-Pointer Surface active atomic oxygen was detected using the DRIFT technique. Black-Right-Pointing-Pointer The highest reactivity toward ozone was performed by NH4Z3 zeolite sample. - Abstract: Among indoor pollutants, ozone is recognised to pose a threat to human health. Recently, low cost natural zeolites have been applied as alternative materials for ozone abatement. In this work, the effect of compensating cation content of natural zeolite on ozone removal is studied. A Chilean natural zeolite is used here as starting material. The amount of compensating cations in the zeolite framework was modified by ion exchange using an ammonium sulphate solution (0.1 mol L{sup -1}). Characterisation of natural and modified zeolites were performed by X-ray powder diffraction (XRD), nitrogen adsorption at 77 K, elemental analysis, X-ray fluorescence (XRF), thermogravimetric analysis coupled with mass spectroscopy (TGA-MS), and temperature-programmed desorption of ammonia (NH{sub 3}-TPD). Ozone adsorption and/or decomposition on natural and modified zeolites were studied by diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS). Results show that the zeolite compensating cation content affects ozone interaction with zeolite active sites. Ammonium ion-exchange treatments followed by thermal out-gassing at 823 K, reduces ozone diffusion resistance inside the zeolite framework, increasing ozone abatement on zeolite surface active sites. Weak and strong Lewis acid sites of zeolite surface are identified here as the main active sites responsible of ozone removal.

  10. Synthesis and Properties of Nanoparticle Forms Saponite Clay, Cancrinite Zeolite and Phase Mixtures Thereof.

    Science.gov (United States)

    Shao, Hua; Pinnavaia, Thomas J

    2010-09-01

    The low-temperature synthesis (90°C) of nanoparticle forms of a pure phase smectic clay (saponite) and zeolite (cancrinite) is reported, along with phase mixtures thereof. A synthesis gel corresponding to the Si:Al:Mg unit cell composition of saponite (3.6:0.40:3.0) and a NaOH/Si ratio of 1.39 affords the pure phase clay with disordered nanolayer stacking. Progressive increases in the NaOH/Si ratio up to a value of 8.33 results in the co-crystallization of first garronite and then cancrinite zeolites with nanolath morphology. The resulting phase mixtures exhibit a compound particulate structure of intertwined saponite nanolayers and cancrinite nanolaths that cannot be formed through physical mixing of the pure phase end members. Under magnesium-free conditions, pure phase cancrinite nanocrystals are formed. The Si/Al ratio of the reaction mixture affects the particle morphology as well as the chemical composition of the cancrinite zeolite. Ordinarily, cancrinite crystallizes with a Si/Al ratio of 1.0, but a silicon-rich form of the zeolite (Si/Al=1.25) is crystallized at low temperature from a silica rich synthesis gel, as evidenced by (29)Si NMR spectroscopy and XEDS-TEM. Owing to the exceptionally high external surface areas of the pure phase clay (875 m(2)/g) and zeolite end members (8.9 - 40 m(2)/g), as well as their unique mixed phase composites (124 - 329 m(2)/g), these synthetic derivatives are promising model nanoparticles for studies of the bioavailability of poly-aromatic hydrocarbons immobilized in silicate bearing sediments and soils.

  11. Obtaining of iron particles of nanometer size in a natural zeolite

    International Nuclear Information System (INIS)

    Xingu C, E. G.

    2013-01-01

    The zeolites are aluminosilicates with cavities that can act as molecular sieve. Their crystalline structure is formed by tetrahedrons that get together giving place to a three-dimensional net, in which each oxygen is shared by two silicon atoms, being this way part of the tecto silicate minerals, its external and internal areas reach the hundred square meters for gram, they are located in a natural way in a large part of earth crust and also exist in a synthetic way. In Mexico there are different locations of zeolitic material whose important component is the clinoptilolite. In this work the results of three zeolitic materials coming from San Luis Potosi are shown, the samples were milled and sieved for its initial characterization, to know its chemical composition, crystalline phases, morphology, topology and thermal behavior before and after its homo-ionization with sodium chloride, its use as support of iron particles of nanometer size. The description of the synthesis of iron particles of nanometer size is also presented, as well as the comparison with the particles of nanometer size synthesized without support after its characterization. The characterization techniques used during the experimental work were: Scanning electron microscopy, X-ray diffraction, Infrared spectroscopy, specific area by means of BET and thermogravimetry analysis. (Author)

  12. CoX zeolites and their exchange with deuterium

    Energy Technology Data Exchange (ETDEWEB)

    Novakova, J; Kubelkova, L; Jiru, P [Ceskoslovenska Akademie Ved, Prague. Ustav Fyzikalni Chemie

    1976-04-01

    An analysis of the gaseous phase using a mass spectrometer and analysis of the solid phase using an infrared spectrophotometer was made to investigate the deuterium exchange with hydrogen mostly bound in hydroxyl groups of zeolites CoX(21 and 47%) and NaX. It was found that with the increasing amount of cobalt ions the number of exchangeable hydrogens of the zeolite increases; the respective types of the hydrogen are discussed with respect to the particular dehydration temperatures. The rate of the D/sub 2/+OH exchange is substantially faster with the CoX than with the NaX zeolite, and exhibits a decrease with increasing dehydration. On the other hand, the rate of D/sub 2/+H/sub 2/ exchange without zeolite hydrogen incorporation, catalyzed by CoX zeolites, increases with increasing dehydration. The increased activation of gaseous hydrogen molecules is related to the presence in the zeolite of cobalt ions whose properties change during dehydration with the change in their environment. Hydroxyl groups of the CoX zeolites are not equivalent during the exchange; the hydroxyl hydrogens of the 3740 cm/sup -1/ band are exchanged more slowly than are the other hydrogens.

  13. CoX zeolites and their exchange with deuterium

    International Nuclear Information System (INIS)

    Novakova, J.; Kubelkova, L.; Jiru, P.

    1976-01-01

    An analysis of the gaseous phase using a mass spectrometer and analysis of the solid phase using an infrared spectrophotometer was made to investigate the deuterium exchange with hydrogen mostly bound in hydroxyl groups of zeolites CoX(21 and 47%) and NaX. It was found that with the increasing amount of cobalt ions the number of exchangeable hydrogens of the zeolite increases; the respective types of the hydrogen are discussed with respect to the particular dehydration temperatures. The rate of the D 2 +OH exchange is substantially faster with the CoX than with the NaX zeolite, and exhibits a decrease with increasing dehydration. On the other hand, the rate of D 2 +H 2 exchange without zeolite hydrogen incorporation, catalyzed by CoX zeolites, increases with increasing dehydration. The increased activation of gaseous hydrogen molecules is related to the presence in the zeolite of cobalt ions whose properties change during dehydration with the change in their environment. Hydroxyl groups of the CoX zeolites are not equivalent during the exchange; the hydroxyl hydrogens of the 3740 cm -1 band are exchanged more slowly than are the other hydrogens. (author)

  14. Dry method for recycling iodine-loaded silver zeolite

    International Nuclear Information System (INIS)

    Thomas, T.R.; Staples, B.A.; Murphy, L.P.

    1978-01-01

    Fission product iodine is removed from a waste gas stream and stored by passing the gas stream through a bed of silver-exchanged zeolite until the zeolite is loaded with iodine, passing dry hydrogen gas through the bed to remove the iodine and regenerate the bed, and passing the hydrogen stream containing the hydrogen iodide thus formed through a lead-exchanged zeolite which absorbs the radioactive iodine from the gas stream and permanently storing the lead-exchanged zeolite loaded with radioactive iodine

  15. Suspending Zeolite Particles In Tanks

    International Nuclear Information System (INIS)

    Poirier, M.R.

    1999-01-01

    The Savannah River Site (SRS) is in the process of removing waste (sludge and salt cake) from million gallon waste tanks. The current practice for removing waste from the tanks is adding water, agitating the tanks with long shaft vertical centrifugal pumps, and pumping the sludge/salt solution from the tank to downstream treatment processes. This practice has left sludge heels (tilde 30,000 gallons) in the bottom of the tanks. SRS is evaluating shrouded axial impeller mixers for removing the sludge heels in the waste tanks. The authors conducted a test program to determine mixer requirements for suspending sludge heels using the shrouded axial impeller mixers. The tests were performed with zeolite in scaled tanks which have diameters of 1.5, 6.0, and 18.75 feet. The mixer speeds required to suspend zeolite particles were measured at each scale. The data were analyzed with various scaling methods to compare their ability to describe the suspension of insoluble solids with the mixers and to apply the data to a full-scale waste tank. The impact of changes in particle properties and operating parameters was also evaluated. The conclusions of the work are: Scaling of the suspension of fast settling zeolite particles was best described by the constant power per unit volume method. Increasing the zeolite particle concentration increased the required mixer power needed to suspend the particles. Decreasing the zeolite particle size from 0.7 mm 0.3 mm decreased the required mixer power needed to suspend the particles. Increasing the number of mixers in the tank decreased the required mixer power needed to suspend the particles. A velocity of 1.6 ft/sec two inches above the tank bottom is needed to suspend zeolite particles

  16. Removal of strontium ions from solutions using granulated zeolites

    International Nuclear Information System (INIS)

    Bronic, J.; Subotic, B.

    1992-01-01

    The ion-exchange process on columns filled with granulated zeolites is determined by several physico-chemical parameters. The influence of these parameters (zeolite type, concentration of exchangeable ions in solution, temperature, flow rate, etc.) on the kinetics of ion-exchange process was studied by measuring the Sr 2+ ion concentration in solution before and after passing through a column filled with various granulated zeolites (zeolite 13X, zeolite A and synthetic mordenite). Using the experimental technique of radioactive labeling by 89 Sr, the distribution of Sr 2+ ions in column fillings were also determined. From the results obtained, the optimal conditions for the most efficient removal of strontium ions from solutions using granulated zeolites can be defined. (author) 24 refs.; 9 figs

  17. Exchange of deuterium with hydrogen of zeolite catalyst surface

    International Nuclear Information System (INIS)

    Minachev, Kh.M.; Dmitriev, R.V.; Penchev, V.; Kanazirev, V.; Minchev, Kh.; Kasimov, Ch.K.; Bylgarska Akademiya na Naukite, Sofia. Inst. za Obshta i Organichna Khimiya; AN Azerbajdzhanskoj SSR, Baku. Inst. Neftekhimicheskikh Protsessov)

    1981-01-01

    Isotope heteromolecular exchange of hydrogen on the reduced nickel-containing zeolites takes places at the temperatures above 100 deg and it is controlled by activated hydrogen transfer from metal particles on the substrate surface. High-temperature redox treatment of nickel-containing zeolites results in the formation of large nickel crystallites on zeolite external faces. The rest part of nickel remains in zeolite pores and conditions a high promoting effect in the exchange reaction. Catalytic activity of reduced zeolites NiCaNaY in toluene disproportionation increases considerably only in the cases when nickel is introduced into zeolite by means of ion exchange. Close spatial location of nickel particles and OH groups promotes the procedure of both isotope exchange and disproportionation of toluene [ru

  18. Effects of aeration and natural zeolite on ammonium removal during the treatment of sewage by mesocosm-scale constructed wetlands.

    Science.gov (United States)

    Araya, F; Vera, I; Sáez, K; Vidal, G

    2016-01-01

    The objective was to evaluate the effects of intermittent artificial aeration cycles and natural zeolite as a support medium, in addition to the contribution of plants (Schoenoplectus californicus) on NH4(+)-N removal during sewage treatment by Constructed Wetlands (CW). Two lines of Mesocosm Constructed Wetland (MCW) were installed: (a) gravel line (i.e. G-Line) and (b) zeolite line (i.e. Z-Line). Aeration increased the NH4(+)-N removal efficiency by 20-45% in the G-Line. Natural zeolite increased the NH4(+)-N removal efficiency by up to 60% in the Z-Line. Plants contributed 15-30% of the NH4(+)-N removal efficiency and no difference between the G-Line and the Z-Line. Conversely, the NH4(+)-N removal rate was shown to only increase with the use of natural zeolite. However, the MCW with natural zeolite, the NH4(+)-N removal rate showed a direct relationship only with the NH4(+)-N influent concentration. Additionally, relationship between the oxygen, energy and area regarding the NH4(+)-N removal efficiency was established for 2.5-12.5 gO2/(kWh-m(2)) in the G-Line and 0.1-2.6 gO2/(kWh-m(2)) in the Z-Line. Finally, it was established that a combination of natural zeolite as a support medium and the aeration strategy in a single CW could regenerate the zeolite's adsorption sites and maintain a given NH4(+)-N removal efficiency over time.

  19. Structure modification of natural zeolite for waste removal application

    Science.gov (United States)

    Widayatno, W. B.

    2018-03-01

    Tremendous industrialization in the last century has led to the generation of huge amount of waste. One of the recent hot research topics is utilizing any advance materials and methods for waste removal. Natural zeolite as an inexpensive porous material with a high abundance holds a key for efficient waste removal owing to its high surface area. However, the microporous structure of natural zeolite hinders the adsorption of waste with a bigger molecular size. In addition, the recovery of natural zeolite after waste adsorption into its pores should also be considered for continuous utilization of this material. In this study, the porosity of natural zeolite from Tasikmalaya, Indonesia, was hydrothermally-modified in a Teflon-lined autoclave filled with certain pore directing agent such as distilled water, KOH, and NH4OH to obtain hierarchical pore structure. After proper drying process, the as-treated natural zeolite is impregnated with iron cation and heat-treated at specified temperature to get Fe-embedded zeolite structure. XRD observation is carried out to ensure the formation of magnetic phase within the zeolite pores. The analysis results show the formation of maghemite phase (γ-Fe2O3) within the zeolite pore structure.

  20. Oxidation of cyclohexane catalyzed by metal-ion-exchanged zeolites.

    Science.gov (United States)

    Sökmen, Ilkay; Sevin, Fatma

    2003-08-01

    The ion-exchange rates and capacities of the zeolite NaY for the Cu(II), Co(II), and Pb(II) metal ions were investigated. Ion-exchange equilibria were achieved in approximately 72 h for all the metal ions. The maximum ion exchange of metal ions into the zeolite was found to be 120 mg Pb(II), 110 mg Cu(II), and 100 mg Co(II) per gram of zeolite NaY. It is observed that the exchange capacity of a zeolite varies with the exchanged metal ion and the amount of metal ions exchanged into zeolite decreases in the sequence Pb(II) > Cu(II) > Co(II). Application of the metal-ion-exchanged zeolites in oxidation of cyclohexane in liquid phase with visible light was examined and it is observed that the order of reactivity of the zeolites for the conversion of cyclohexane to cyclohexanone and cyclohexanol is CuY > CoY > PbY. It is found that conversion increases by increase of the empty active sites of a zeolite and the formation of cyclohexanol is favored initially, but the cyclohexanol is subsequently converted to cyclohexanone.

  1. Ion exchange and hydrolysis reactions in zeolites

    International Nuclear Information System (INIS)

    Harjula, Risto.

    1993-09-01

    Among other uses, zeolites are efficient cation exchangers for aquatic pollution control. At present they they are mainly used in nuclear waste effluent treatment and in detergency. In the thesis, several ion exchange equilibria, important in these main fields of zeolite applications, were studied, with special emphasis on the formulation and calculation of the equilibria. The main interest was the development of thermodynamic formulations for the calculation of zeolite ion exchange equilibria in solutions of low or very low (trace) ion concentration, which are relevant for the removal of trace pollutants, such as radionuclides, from waste waters. Two groups of zeolite-cation systems were studied. First, binary Ca 2+ /Na + exchange in zeolites X and Y, which are of interest for detergency applications. Second, binary Cs + /Na + and Cs + /K + exchanges, and ternary Cs + /Na + /K + exchange in mordenite, which are important in nuclear waste effluent treatment. The thesis is based on five previous publications by author. (100 refs., 7 figs.)

  2. Positron spectroscopy studies of zeolites

    Science.gov (United States)

    Hung, Ku-Jung

    The lineshapes of two-dimensional angular correlation of electron-positron annihilation radiation (2D-ACAR) in alumina and several zeolites were measured as a function of internal surface areas. In all cases, the lineshape parameter S from 2D-ACAR spectra were found to vary proportionally with internal surface area. In order to investigate the Bronsted acidity in NaHY zeolite, the lineshape parameter evaluation from 2D-ACAR measurements for varied acidity in NaHY zeolites by ion-exchange and thermal desorption were presented. The result from this investigation has demonstrated that the Bronsted acidity in NaHY zeolite was found to vary linearly with the lineshape parameter of the angular correlation spectrum of the sample. The lineshapes of 2D-ACAR spectra were determined for different base adsorbed HY-zeolite samples under a temperature controlled heating system in order to investigate, in-situ, the acid strength and number of Bronsted acid sites in the sample. Results have shown that the lineshape parameter of the angular correlation spectrum of the sample increases with the strength of adsorbed base and decreases with the number of Bronsted acid sites in the sample. This indicated that the lineshape parameter is sensitive to all of the strengths and concentrations of Bronsted acid sites in the HY-zeolite samples. The result from this study has also demonstrated that the large size base, pyridine, would reduce the possibility of positronium formation in the sample by filling the cage to eliminate the internal surface areas where the positroniums are likely to form. However, the small size base, ammonia, did not show any effect on the internal surface areas. Owing to the fact that this technique monitors only the Bronsted acid sites that situate on the surface which relates to the catalytic activity, there is little ambiguity about the location of the source of information obtained. The findings presented in this dissertation point out the fact that such lineshape

  3. Mesoporous MEL, BEA, and FAU zeolite crystals obtained by in situ formation of carbon template over metal nanoparticles

    DEFF Research Database (Denmark)

    Abildstrøm, Jacob Oskar; Ali, Zahra Nasrudin; Mentzel, Uffe Vie

    2016-01-01

    Here, we report the synthesis and characterization of hierarchical zeolite materials with MEL, BEA and FAU structures. The synthesis is based on the carbon templating method with an in situ-generated carbon template. Through the decomposition of methane and deposition of coke over nickel nanopart......Here, we report the synthesis and characterization of hierarchical zeolite materials with MEL, BEA and FAU structures. The synthesis is based on the carbon templating method with an in situ-generated carbon template. Through the decomposition of methane and deposition of coke over nickel...... nanoparticles supported on silica, a carbon–silica composite is obtained and exploited as a combined carbon template/silica source for the zeolite synthesis. The mesoporous zeolite materials were all prepared by hydrothermal crystallization in alkaline media followed by removal of the carbon template...... by combustion, which results in zeolite single crystals with intracrystalline pore volumes of up to 0.44 cm3 g−1. The prepared zeolite structures are characterized by XRD, SEM, TEM and N2 physisorption measurements....

  4. Synthesis and characterization of zeolite from coal fly ash

    Science.gov (United States)

    Liu, Yong; Luo, Qiong; Wang, Guodong; Li, Xianlong; Na, Ping

    2018-05-01

    Fly ash (FA) from coal-based thermal power plant was used to synthesize zeolite in NaOH solution with hydrothermal method in this work. Firstly, the effects of calcination and acid treatment on the removal of impurities in fly ash were studied. Then based on the pretreated FA, the effects of alkali concentration, reaction temperature and Si/Al ratio on the synthesis of zeolite were studied in detail. The mineralogy, morphology, thermal behavior, infrared spectrum and specific surface for the synthetic sample were investigated. The results indicated that calcination at 750 °C for 1.5 h can basically remove unburned carbon from FA, and 4 M hydrochloric acid treatment of calcined FA at 90 °C for 2 h will reduce the quality of about 34.3%wt, which are mainly iron, calcium and sulfur elements. The concentration of NaOH, reaction temperature and Si/Al ratio have important effect on the synthesis of zeolite. In this study, 0.5 M NaOH cannot obtain any zeolite. High temperature is beneficial to zeolite synthesis from FA, but easily lead to a variety of zeolites. The synthetic sample contains three kinds of zeolites such as zeolite P, sodalite and zeolite X, when the reaction conditions are 2 M NaOH and 120 °C for 24 h. In this research, quartz always exists in the synthetic sample, but will reduce with the increase of temperature. The synthetic zeolite has the specific surface area of about 42 m2 g‑1 and better thermal stability.

  5. Removal of Sulphate and Manganese on Synthetic Wastewater in Sulphate Reducing Bioreactor Using Indonesian Natural Zeolite

    Directory of Open Access Journals (Sweden)

    Endah Retnaningrum

    2017-07-01

    Full Text Available The present research was conducted to investigate sulphate and manganese removal from synthetic wastewater. The continuous laboratory scale of down-flow fluidized-bed reactor (DFBR using sulphate reducing bacteria (SRB consortium and Indonesian natural zeolite as a bacterial support material was designed. At 9 days operation, maximum sulphate and manganese removal was observed to be 23% and 15.4%, respectively. The pH values were also changed to neutral. The population of SRB increased which effect on the raising of their activity for removing sulphate and manganese. Using the scanning electronic microscopy (SEM, it was observed that natural zeolite possesses excellent physical characteristics as a bacterial support material in DFBR. The imaging SEM result of SRB consortium on zeolite surface clearly showed the developed SRB biofilm on that particle. Analysis result of EDX confirmed that manganese was precipitated as manganese–sulfides.

  6. Synthesis of LTA zeolite for bacterial adhesion

    Energy Technology Data Exchange (ETDEWEB)

    Belaabed, R.; Eabed, S.; Addaou, A.; Laajab, A.; Rodriguez, M.A.; Lahsini, A.

    2016-07-01

    High affinity and adhesion capacity for Gram-positive bacteria on minerals has been widely studied. In this work the adhesion of bacteria on synthesized zeolite has been studied. The Zeolite Linde Type A (LTA) has been synthesized using hydrothermal route using processing parameters to obtain low cost materials. For adhesion studies Staphylococcus aureus and Bacillus subtilis were used as Gram-positive bacteria, Escherichia coli and Pseudomonas aeruginosa are used as Gram-negative bacteria. X-ray diffraction, environmental scanning electron microscope and attenuated total reflection-Fourier transform infrared spectroscopy were used to characterize the synthesized zeolite. To evaluate the bacterial adhesion to zeolite LTA the hydrophobicity and surface properties are examined using contact angle measurement. (Author)

  7. Synthesis of K2O/Zeolite catalysts by KOH impregnation for biodiesel production from waste frying oil

    Science.gov (United States)

    Fitriana, N.; Husin, H.; Yanti, D.; Pontas, K.; Alam, P. N.; Ridho, M.; Iskandar

    2018-03-01

    K2O/Zeolite compounds were successfully synthesized using KOH as starting material and natural zeolite as support. The catalysts were calcined at 500°C for 3 h and then characterized by X-Ray Diffractometer (XRD) and Scanning Electron Microscopy (SEM). The SEM images reveal that the zeolite and K2O/zeolite particles are irregular in shape (100 to 400 nm). The independent variables were impregnated amounts of KOH (15 - 25%), catalyst to oil ratios of 1.0 - 6.0 wt.%, and reaction time of 2 h. The highest biodiesel yield of 95% was produced from the reaction with 2.1 wt.% catalyst of 25% KOH impregnated. The properties of produced biodiesel complied with SNI. The catalytic stability test showed that the 25% KOH impregnated catalyst was stable.

  8. Facile preparation of hierarchically porous diatomite/MFI-type zeolite composites and their performance of benzene adsorption: the effects of NaOH etching pretreatment.

    Science.gov (United States)

    Yu, Wenbin; Yuan, Peng; Liu, Dong; Deng, Liangliang; Yuan, Weiwei; Tao, Bo; Cheng, Hefa; Chen, Fanrong

    2015-03-21

    Hierarchically porous diatomite/MFI-type zeolite (Dt/Z) composites with excellent benzene adsorption performance were prepared. The hierarchical porosity was generated from the microporous zeolite coated at the surface of diatom frustules and from the macroporous diatomite support. A facile NaOH etching method was employed for the first time to treat the frustule support, followed by hydrothermal growth of MFI-type zeolite at the surface of frustules previously seeded with nanocrystalline silicalite-1 (Sil-1). NaOH etching enlarged the pores on diatom frustules and further increased the coated zeolite contents (W(z)). The central macropore size of the diatom frustules increased from approximately 200-500 nm to 400-1000 nm after NaOH etching. The W(z) could reach 61.2%, while the macroporosity of the composites was largely preserved due to more voids for zeolite coating being formed by NaOH etching. The Dt/Z composites exhibited higher benzene adsorption capacity per unit mass of zeolite and less mass transfer resistance than Sil-1, evaluated via a method of breakthrough curves. These results demonstrate that etching of a diatomite support is a facile but crucial process for the preparation of Dt/Z composites, enabling the resulting composites to become promising candidates for uses in volatile organic compounds emission control. Copyright © 2014 Elsevier B.V. All rights reserved.

  9. Nanocellulose-Zeolite Composite Films for Odor Elimination.

    Science.gov (United States)

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

    2015-07-08

    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 μm 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.

  10. Thermochemical properties of copper forms of zeolite ZSM5 containing dimethylethylenediamine

    Czech Academy of Sciences Publication Activity Database

    Čuvanová, S.; Reháková, M.; Finocchiaro, P.; Pollicino, A.; Bastl, Zdeněk; Nagyová, S.; Fajnor, V. Š.

    2007-01-01

    Roč. 452, č. 1 (2007), s. 13-19 ISSN 0040-6031 R&D Projects: GA AV ČR 1ET400400413 Grant - others:GA SR(SK) 1/1385/04; GA SR(SK) 1/1373/04 Institutional research plan: CEZ:AV0Z40400503 Keywords : ZSM-5 * dimethylethylenediamine * copper * thermal analysis * XPS Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 1.562, year: 2007

  11. Cultivation of Chlorella vulgaris and Arthrospira platensis with Recovered Phosphorus from Wastewater by Means of Zeolite Sorption

    Science.gov (United States)

    Markou, Giorgos; Depraetere, Orily; Vandamme, Dries; Muylaert, Koenraad

    2015-01-01

    In this study, zeolite was employed for the separation and recovery of P from synthetic wastewater and its use as phosphorus (P) source for the cultivation of the green microalga Chlorella vulgaris and the cyanobacterium Arthrospira (Spirulina) platensis. At P-loaded zeolite concentration of 0.15–1 g/L, in which P was limited, the two species displayed quite different behavior regarding their growth and biomass composition. C. vulgaris preferred to increase the intracellular P and did not synthesize biomass, while A. platensis synthesized biomass keeping the intracellular P as low as possible. In addition under P limitation, C. vulgaris did display some little alteration of the biomass composition, while A. platensis did it significantly, accumulating carbohydrates around 70% from about 15%–20% (control). Both species could desorb P from zeolite biologically. A. platensis could recover over 65% and C. vulgaris 25% of the P bounded onto zeolite. When P-loaded zeolite concentration increased to 5 g/L, P was adequate to support growth for both species. Especially in the case of C. vulgaris, growth was stimulated from the presence of P-loaded zeolite and produced more biomass compared to the control. PMID:25690037

  12. Cultivation of Chlorella vulgaris and Arthrospira platensis with Recovered Phosphorus from Wastewater by Means of Zeolite Sorption

    Directory of Open Access Journals (Sweden)

    Giorgos Markou

    2015-02-01

    Full Text Available In this study, zeolite was employed for the separation and recovery of P from synthetic wastewater and its use as phosphorus (P source for the cultivation of the green microalga Chlorella vulgaris and the cyanobacterium Arthrospira (Spirulina platensis. At P-loaded zeolite concentration of 0.15–1 g/L, in which P was limited, the two species displayed quite different behavior regarding their growth and biomass composition. C. vulgaris preferred to increase the intracellular P and did not synthesize biomass, while A. platensis synthesized biomass keeping the intracellular P as low as possible. In addition under P limitation, C. vulgaris did display some little alteration of the biomass composition, while A. platensis did it significantly, accumulating carbohydrates around 70% from about 15%–20% (control. Both species could desorb P from zeolite biologically. A. platensis could recover over 65% and C. vulgaris 25% of the P bounded onto zeolite. When P-loaded zeolite concentration increased to 5 g/L, P was adequate to support growth for both species. Especially in the case of C. vulgaris, growth was stimulated from the presence of P-loaded zeolite and produced more biomass compared to the control.

  13. Diagenetic Quartz Morphologies and Zeolite formation

    DEFF Research Database (Denmark)

    Kazerouni, Afsoon Moatari; Hansen, Rikke Weibel; Friis, Henrik

    the Siri Canyon wells.  Volcanic lithoclasts are strongly altered and associated with diagenetic opal/ microquartz coatings and zeoliteZeolite crystals formed simultaneously with opal and prior to microquartz but dissolved with increased burial depth.  The dissolution of zeolite followed two steps...... in samples where no volcanic ash is demonstrated; it seems that a rapid supply of dissolved silica from dissolution of siliceous fossils was the main reason for the early co-precipitation of opal and zeolite. There are two important sources for Si: 1) Biogenic opal from diatoms or radiolarians, which...... are abundant in some of associated shales; and 2) volcanic ash. The dissolution of biogenic silica may result in a rapid release of silica thereby promoting the formation of diagenetic opal/microquartz, but there may be a limited release of Al. A limited release of Al may result in precipitation of Si...

  14. Multi-elemental characterization of Cuban natural zeolites

    International Nuclear Information System (INIS)

    Rizo, O.D.; Peraza, E.F.H.

    1997-01-01

    Concentration of 38 elements in samples from four important Cuban zeolite beds have been obtained by Instrumental Neutron Activation (INAA) and X-ray Fluorescence analyses (XRFA). In comparison with other analytical techniques good agreement was reached. The concentration values of minor element Ba, Sr, Zn and Mn and 25 trace element (including 9 REE) are at the first time reported in Cuban zeolite. It is important for the zeolite evaluation in different industrial uses. (author)

  15. Multi-elemental characterization of Cuban natural zeolites

    International Nuclear Information System (INIS)

    Diaz Rizo, O.; Herrera Peraza, E.F.

    1996-01-01

    Concentrations of 38 elements in samples from four important Cuban zeolite bed have beam obtained by Instrumental Neutron Activation (INAA) and X-Ray Fluorescence Analysis (XRFA). In comparison with other analytical techniques good agreement was achieved. The concentration values of minor element Ba, Sr, Zn, and Mn, and 25 trace element (including 9 REE) are at the first time reported in Cuban zeolite. It is important for the zeolite evaluation in different industrial uses

  16. Synthesis of uniform-sized zeolite from windshield waste

    International Nuclear Information System (INIS)

    Kim, Jae-Chan; Choi, Mingu; Song, Hee Jo; Park, Jung Eun; Yoon, Jin-Ho; Park, Kyung-Soo; Lee, Chan Gi; Kim, Dong-Wan

    2015-01-01

    We demonstrate the synthesis of A-type zeolite from mechanically milled windshield waste via acid treatment and a low-temperature hydrothermal method. As-received windshield cullet was crushed to a fine powder and impurities were removed by HNO 3 treatment. The resulting glass powder was used as the source material for the hydrothermal synthesis of A-type zeolite. Crystal structure, morphology, and elemental composition changes of the windshield waste were evaluated at each step of the process through scanning electron microscopy, X-ray diffraction, X-ray fluorescence spectrometry, etc. After a high-energy milling process, the glass had an average particle size of 520 nm; after acid treatment, its composition was over 94% silica. Zeolite was successfully synthesized in the A-type phase with a uniform cubic shape. - Highlights: • Environmental-friendly recycling of windshield waste for high valuable product of zeolite. • Synthesis of zeolite form windshield waste via a low-temperature hydrothermal process. • High-energy milling effect on the uniform cubic shape and high-purity A-type zeolite.

  17. Zeolites with Continuously Tuneable Porosity**

    Science.gov (United States)

    Wheatley, Paul S; Chlubná-Eliášová, Pavla; Greer, Heather; Zhou, Wuzong; Seymour, Valerie R; Dawson, Daniel M; Ashbrook, Sharon E; Pinar, Ana B; McCusker, Lynne B; Opanasenko, Maksym; Čejka, Jiří; Morris, Russell E

    2014-01-01

    Zeolites are important materials whose utility in industry depends on the nature of their porous structure. Control over microporosity is therefore a vitally important target. Unfortunately, traditional methods for controlling porosity, in particular the use of organic structure-directing agents, are relatively coarse and provide almost no opportunity to tune the porosity as required. Here we show how zeolites with a continuously tuneable surface area and micropore volume over a wide range can be prepared. This means that a particular surface area or micropore volume can be precisely tuned. The range of porosity we can target covers the whole range of useful zeolite porosity: from small pores consisting of 8-rings all the way to extra-large pores consisting of 14-rings. PMID:25284344

  18. Removal of radiocesium from low level radioactive effluents by hexacyanoferrate loaded synthetic zeolite. Laboratory to pilot plant scale demonstration

    Energy Technology Data Exchange (ETDEWEB)

    Banerjee, Dayamoy; Rao, Manjula A.; Khot, Shantinath A.; Shah, Jayesh G.; Banerjee, Kalyan [Bhabha Atomic Research Centre, Mumbai (India). Nuclear Recycle Group; Pawaskar, Chandrahas S.; Gangadharan, Anand; Rao, Shankar N.; Jain, Savita [Bhabha Atomic Research Centre, Mumbai (India)

    2017-06-01

    Present paper reports removal of radiocesium from low level waste using a modified sorbent (13X-CFC) prepared by in-situ precipitation of potassium copper hexacyanoferrate(II) inside the macropores of a synthetic zeolite. The Cs exchange isotherm of the sorbent is established and it found to follow Fruendlich absorption isotherm equation. It is varified that presence of hexacyanoferrate on zeolite facilitates rapid Cs uptake performance. This is further confirmed in laboratory scale column tests, wherein excellent Cs removal performance from low level waste simulant was observed even at higher flow rates (40 bed volumes per hour). The utility of the sorbent is established through successful demonstration in a pilot scale (50 L) trial with almost complete removal of {sup 137}Cs from more than 14,000 bed volumes of actual low level waste. The sorbent, owing to its low cost and excellent {sup 137}Cs removal performance, is expected to find application in treatment of very low active waste streams.

  19. Introduction to chemistry of crystalline zeolites and its applications

    International Nuclear Information System (INIS)

    Lobo Cabezas, Raul Francisco

    2006-01-01

    Establishes the zeolites as the most important group of solid acids and its relation to the contemporaneous chemical industry. It describes that zeolites are used in the following applications: refineries, chemicals/petrochemicals, environmental chemistry, separation of gas, adsorbent ia and ionic exchange in water purification in mineral processes, medicine and agricultural industry. Zeolites are defined as crystalline aluminium silicates with a compound structure of interconnected tetrahedrons. It mentions the key components in zeolites structure. It focuses that structural basic unity of the zeolite is the tetrahedron and compound structural unities are: cells and columns. Besides, it describes that pore system defines a lot of all its properties; but chemical composition affects them. Composition and properties of zeolites are established: adsorption, molecular sieves, acidity, selectivity, transition state in the hydrocarbon's chemistry. It concludes that the newer application of zeolite is in oxidations: Titanium-Silicate-1; production of propylene's oxide using peroxide of hydrogen as oxidizing. The catalysis is an active area of research, and the most popular areas are related to chemicals and the environment [es

  20. Environmental application of modified natural zeolites

    International Nuclear Information System (INIS)

    Nikashina, V.A.; Myasoedov, B.F.

    1998-01-01

    The following techniques were used for the chemical modification of the natural zeolites: (1) treatment of natural zeolites with organic substances. Examples of applications of these sorbents to the decontamination and disinfection of solutions of different composition and surface waters are presented. (2) Treatment of the natural zeolites with a inorganic substances. (2.1) The clinoptilolite-rich tuffs were treated with a hot suspensions of freshly precipitated magnetite. This leads to the preparation of sorbents possessing magnetic properties. The radionuclides and heavy metals recovery from soils and silts was investigated using different soil and ferromagnetic zeolite weights ratios and contact times. Different soils and sorbent of varying capacities were used for these investigations. As example, the recovery 137 Cs and 85 Sr from soils of different nature is presented. (2.2) Treatment of natural zeolites with Fe-containing solutions of Fe-containing natural waters. The filtration of these solutions through clinoptilolite-rich tuffs makes leads to preparation of materials possessing high selectivity to PO 4 3- ions. The properties of these sorbents can be utilized for the PO 4 3+ decontamination of waters (e.g. waste waters) and for the subsequent use of these materials in agriculture as fertilizers.(author)

  1. Removal of cesium radioisotopes from solutions using granulated zeolites

    International Nuclear Information System (INIS)

    Bronic, J.; Subotic, B.

    1991-01-01

    The influence of type of zeolite and the flow rate of solution through the column on the removal efficiency of radioactive cesium ions from solution has been investigated. The analysis of the change in the concentration of cesium ions in the solutions and distribution of cesium ions in the column fillings (granulated zeolites), after passing the solutions through the columns filled with various granulated zeolites (zeolite 4A, zeolite 13X, synthetic mordenite) was performed. On the basis of the results of this study, the conditions for the most efficient removal of cesium ions from solutions have been discussed. (author) 35 refs.; 9 figs.; 1 tab

  2. Catalytic Oxidation by Transition Metal Ions in Zeolites.

    Science.gov (United States)

    1984-09-28

    exotic schemes were developed. It was previously demonstrated that MoCI5 may be reacted with a HYu (here Yu denotes a steam-stabilized or...34ultrastable" zeolite) to form a MoYu zeolite and HC1 which is removed from the system.1 In this study, MoYu zeolites have been prepared by reacting HYu with Mo

  3. Ion exchange properties of zeolite-containing catalysts

    Energy Technology Data Exchange (ETDEWEB)

    Koval' chuk, L V; Takhtarova, G N; Topchieva, K V [Moskovskii Gosudarstvennyi Univ. (USSR). Kafedra Fizicheskoi Khimii

    1975-03-01

    In the paper the reaction of sodium ion exchange for ammonium cations, cations of calcium and lanthanum in the amorphous aluminium silicate Na/sub 0,856/(AlO/sub 2/)(SiO/sub 2/)/sub 9,831/, zeolite Na/sub 1/(AlO/sub 2/)(SiO/sub 2/)/sub 2,33/ and zeolite containing catalyst Na/sub 1,09/(AlO/sub 2/)(SiOsub(2))/sub 7,93/ were studied; exchange isotherms of sodium for ammonium, calcium and lanthanium are presented. Results received in the study indicate high selectivity of zeolite for calcium and lanthanum cations in comparison with amorphous aluminium silicate and also display electroselectivity effect. The highest separation coefficient takes place for lanthanum in the sodium exchange in zeolite.

  4. Zeolites - the relationship between morphostructural parameters and adsorptive/molecular sieving/catalytic properties of porous solids (models and practices)

    International Nuclear Information System (INIS)

    Hartomo, A.J.; Soendoror, N.P.C.

    1989-01-01

    Zeolites receive great attention among researchers today primarily because of their numerous industrial uses and applications, ranging from water treatment to petroleum industries, concerning adsorption, molecular sieving and/or catalysis. Some important progress taking place during the last few years - theoretical and experimental are discussed. In Indonesia, zeolites of natural origin are found in many places including the western and eastern part of Java Island. Works preparing, modifying and characterizing their performance whether by spectroscopic, thermochemical or volumetric methods are presented. Cooperation in R and D is still to be seriously and constantly increased/intensified. (Auth.). 22 refs.; 10 figs.; 2 tabs

  5. Microwave heating and the fast ADOR process for preparing zeolites

    Czech Academy of Sciences Publication Activity Database

    Navarro, M.; Morris, S. A.; Mayoral, A.; Čejka, Jiří; Morris, R. E.

    2017-01-01

    Roč. 5, č. 17 (2017), s. 8037-8043 ISSN 2050-7488 R&D Projects: GA ČR GBP106/12/G015 Institutional support: RVO:61388955 Keywords : membranes * zeolites * microwave heating Subject RIV: CF - Physical ; Theoretical Chemistry OBOR OECD: Physical chemistry Impact factor: 8.867, year: 2016

  6. Critical evaluation of the role of the distribution of Al atoms in the framework for the activity of metallo-zeolites in redox N2O/NOx reactions

    Czech Academy of Sciences Publication Activity Database

    Sobalík, Zdeněk; Sazama, Petr; Dědeček, Jiří; Wichterlová, Blanka

    2014-01-01

    Roč. 474, MAR 2014 (2014), s. 178-185 ISSN 0926-860X R&D Projects: GA ČR GAP106/11/0624 Institutional support: RVO:61388955 Keywords : Cu-zeolite * Co-zeolite * Fe-zeolite Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 3.942, year: 2014

  7. Advances in nanosized zeolites

    Science.gov (United States)

    Mintova, Svetlana; Gilson, Jean-Pierre; Valtchev, Valentin

    2013-07-01

    This review highlights recent developments in the synthesis of nanosized zeolites. The strategies available for their preparation (organic-template assisted, organic-template free, and alternative procedures) are discussed. Major breakthroughs achieved by the so-called zeolite crystal engineering and encompass items such as mastering and using the physicochemical properties of the precursor synthesis gel/suspension, optimizing the use of silicon and aluminium precursor sources, the rational use of organic templates and structure-directing inorganic cations, and careful adjustment of synthesis conditions (temperature, pressure, time, heating processes from conventional to microwave and sonication) are addressed. An on-going broad and deep fundamental understanding of the crystallization process, explaining the influence of all variables of this complex set of reactions, underpins an even more rational design of nanosized zeolites with exceptional properties. Finally, the advantages and limitations of these methods are addressed with particular attention to their industrial prospects and utilization in existing and advanced applications.

  8. Synthesis And Characterization Of Pure-Silica- Zeolite-Beta Membrane

    Directory of Open Access Journals (Sweden)

    Yeong Yin Fong

    2017-11-01

    Full Text Available The semiconductor industry needs low dielectric constant (low k-value materials to more advance microprocessor and chips by reducing the size of the device features. In fabricate this context, a new material with lower k value than conventional silica ( k = 3.9 - 4.2 is needed in order to improve the circuit performance. As per the recent International Semiconductor Technology plan, a low-k material with a k = 1.6 will be needed by 2010. The choice of the inorganic zeolite membrane is an attractive option for low k material and suitable for microprocess application.  In the present study, a pure silica zeolite beta membrane coated on the non-porous stainless steel support was synthesized using in situ crystallization of a gel with the composition of  SiO2 : 0.6 TEAOH : 0.6 HF : 10.1 H2O. The crystallization was carried in the presence of tetraethylammonium hydroxide TEA(OH as structure directing agent, fumed silica, HF and deionized water at pH value of 9. The crystallization under hydrothermal conditions at 130oC was carried out for the time period of 14 days. The membrane was characterized by X-Ray Diffraction ( XRD ,  Thermogravimetric Analysis ( TGA , Nitrogen Adsorption and Scanning Electron Microscope ( SEM .   SEM micrographs show highly crystalline, truncated square bipyramidal morphology of pure silica zeolite beta was coated on the non-porous stainless steel support. The membrane dielectric constant, k-value was measured as 2.64 which makes it suitable for the microprocessor applications.

  9. Preparation and photoelectrocatalytic performance of N-doped TiO2/NaY zeolite membrane composite electrode material.

    Science.gov (United States)

    Cheng, Zhi-Lin; Han, Shuai

    2016-01-01

    A novel composite electrode material based on a N-doped TiO2-loaded NaY zeolite membrane (N-doped TiO2/NaY zeolite membrane) for photoelectrocatalysis was presented. X-ray diffraction (XRD), scanning electron microscopy (SEM), UV-visible (UV-vis) and X-ray photoelectron spectroscopy (XPS) characterization techniques were used to analyze the structure of the N-doped TiO2/NaY zeolite membrane. The XRD and SEM results verified that the N-doped TiO2 nanoparticles with the size of ca. 20 nm have been successfully loaded on the porous stainless steel-supported NaY zeolite membrane. The UV-vis result showed that the N-doped TiO2/NaY zeolite membrane exhibited a more obvious red-shift than that of N-TiO2 nanoparticles. The XPS characterization revealed that the doping of N element into TiO2 was successfully achieved. The photoelectrocatalysis performance of the N-doped TiO2/NaY zeolite membrane composite electrode material was evaluated by phenol removal and also the effects of reaction conditions on the catalytic performance were investigated. Owing to exhibiting an excellent catalytic activity and good recycling stability, the N-doped TiO2/NaY zeolite membrane composite electrode material was of promising application for photoelectrocatalysis in wastewater treatment.

  10. Preparation of zeolite supported TiO{sub 2}, ZnO and ZrO{sub 2} and the study on their catalytic activity in NO{sub x} reduction and 1-pentanol dehydration

    Energy Technology Data Exchange (ETDEWEB)

    Fatimah, Is [Chemistry Department, Islamic University of Indonesia Kampus Terpadu UII, Jl. Kaliurang Km 14, Sleman, Yogyakarta (Indonesia)

    2016-03-29

    Preparation of zeolite supported TiO{sub 2}, ZnO and ZrO{sub 2} and their catalytic activity was studied. Activated natural zeolite from Indonesia was utilized for the preparation and catalytic activity test on NO{sub x} reduction by NH{sub 3} and also 1-pentanol dehydration were examined. Physicochemical characterization of materials was studied by x-ray diffraction (XRD) measurement, scanning electron microscope, solid acidity determination and also gas sorption analysis. The results confirmed that the preparation gives some improvements on physicochemical characters suitable for catalysis mechanism in those reactions. Solid acidity and specific surface area contributed significantly to the activity.

  11. Adsorption of Carbon Dioxide on Sodium and Potassium Forms of STI Zeolite

    Czech Academy of Sciences Publication Activity Database

    Zukal, Arnošt; Zones, S. I.; Kubů, Martin; Davis, T. M.; Čejka, Jiří

    2012-01-01

    Roč. 77, č. 8 (2012), s. 675-681 ISSN 2192-6506 R&D Projects: GA ČR GA203/08/0604 Institutional support: RVO:61388955 Keywords : adsorption * carbon dioxide * zeolites Subject RIV: CF - Physical ; Theoretical Chemistry

  12. Pengaruh Kandungan Ca Pada Cao-zeolit Terhadap Kemampuan Adsorpsi Nitrogen

    OpenAIRE

    M Nasikin; Tania Surya Utami; Agustina TP Siahaan

    2002-01-01

    In industry, Ca zeolite is used as nitrogen selective adsorbent with the use of PSA (Pressure Swing Adsorption)/VSA (Vacuum Swing Adsorption) methods. Natural zeolite modified to be Cao-zeolite by ion exchange process using Ca(OH)2. Adsorption test was done on CaO-zeolite with different Ca concentration to understand how it's adsorption phenomena on oxygen and nitrogen. Adsorption test has been done for CaO-zeolite with Ca concentration = 0,682%, 0,849% and 1,244% to oxygen and nitrogen with ...

  13. An Extra-Large-Pore Zeolite with 24×8×8-Ring Channels Using a Structure-Directing Agent Derived from Traditional Chinese Medicine.

    Science.gov (United States)

    Zhang, Chuanqi; Kapaca, Elina; Li, Jiyang; Liu, Yunling; Yi, Xianfeng; Zheng, Anmin; Zou, Xiaodong; Jiang, Jiuxing; Yu, Jihong

    2018-03-12

    Extra-large-pore zeolites have attracted much interest because of their important applications because for processing larger molecules. Although great progress has been made in academic science and industry, it is challenging to synthesize these materials. A new extra-large-pore zeolite SYSU-3 (Sun Yat-sen University no. 3) has been synthesized by using a novel sophoridine derivative as an organic structure-directing agent (OSDA). The framework structure was solved and refined using continuous rotation electron diffraction (cRED) data from nanosized crystals. SYSU-3 exhibits a new zeolite framework topology, which has the first 24×8×8-ring extra-large-pore system and a framework density (FD) as low as 11.4 T/1000 Å 3 . The unique skeleton of the OSDA plays an essential role in the formation of the distinctive zeolite structure. This work provides a new perspective for developing new zeolitic materials by using alkaloids as cost-effective OSDAs. © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  14. The ADOR mechanism for the synthesis of new zeolites

    Czech Academy of Sciences Publication Activity Database

    Eliášová, Pavla; Opanasenko, Maksym; Wheatley, P. S.; Shamzhy, Mariya; Mazur, Michal; Nachtigall, P.; Roth, Wieslaw Jerzy; Morris, R. E.; Čejka, Jiří

    2015-01-01

    Roč. 44, č. 20 (2015), s. 7177-7206 ISSN 0306-0012 R&D Projects: GA ČR GBP106/12/G015; GA ČR(CZ) GP14-30898P Institutional support: RVO:61388955 Keywords : STRUCTURE -DIRECTING AGENTS * LARGE-PORE ZEOLITES * PILLARED MOLECULAR-SIEVE Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 34.090, year: 2015

  15. Synthesis of Zeolite Nanomolecular Sieves of Different Si/Al Ratios

    Directory of Open Access Journals (Sweden)

    Pankaj Sharma

    2015-01-01

    Full Text Available Nanosized zeolite molecular sieves of different Si/Al ratios have been prepared using microwave hydrothermal reactor (MHR for their greater application in separation and catalytic science. The as-synthesized molecular sieves belong to four different type zeolite families: MFI (infinite and high silica, FAU (moderate silica, LTA (low silica and high alumina, and AFI (alumina rich and silica-free. The phase purity of molecular sieves has been assessed by X-ray diffraction (XRD analysis and morphological evaluation done by electron microscopy. Broad XRD peaks reveal that each zeolite molecular sieve sample is composed of nanocrystallites. Scanning electron microscopic images feature the notion that the incorporation of aluminum to MFI zeolite synthesis results in morphological change. The crystals of pure silica MFI zeolite (silicalite-1 have hexagon lump/disk-like shape, whereas MFI zeolite particles with Si/Al molar ratios 250 and 100 have distorted hexagonal lump/disk and pseudo spherical shapes, respectively. Furthermore, phase pure zeolite nanocrystals of octahedron (FAU, cubic (LTA, and rod (AFI shape have been synthesized. The average sizes of MFI, FAU, LTA, and AFI zeolite crystals are 250, 150, 50, and 3000 nm, respectively. Although the length of AFI zeolite rods is in micron scale, the thickness and width are of a few nanometers.

  16. Stability and activity of doped transition metal zeolites in the hydrothermal processing

    Directory of Open Access Journals (Sweden)

    Thomas François Robin

    2015-12-01

    Full Text Available This study investigates the stability and activity of HZSM-5 doped with metals such as molybdenum, nickel, copper and iron in under hydrothermal conditions used for the direct liquefaction of microalgae. Catalysts have been prepared by ion exchange techniques, and MoZSM-5 was also prepared by wet incipient impregnation for comparison. Hydrothermal liquefaction is considered as a potential route to convert microalgae into a sustainable fuel. One of the drawbacks of this process is that the bio-crude produced contains significant levels of nitrogen and oxygen compounds which have an impact on the physical and chemical propriety of the fuel. Heterogeneous catalysts have been shown to improve the quality of the bio-crude by reducing nitrogen and oxygen contents. Zeolites, such as HZSM-5, are strong candidates due to their low cost compared to noble metal catalysts but their stability and activity under hydrothermal conditions is not well understood. The stability of the catalysts has been determined under hydrothermal conditions at 350 °C. Catalysts have been characterised before and after treatment using XRD, BET physisorption and STEM microscopy. Metal leaching was determined by analysis of the water phase following hydrothermal treatment. The inserted cation following ion-exchange can influence the physical properties of HZSM-5 for example molybdenum improves the crystallinity of the zeolite. In general, metal doped zeolites were relatively stable under subcritical water. Activity of the catalysts for processing lipids, protein and microalgae has been assessed. Four feedstocks were selected: sunflower oil, soya proteins, Chlorella and P. ellipsoidea. The catalysts exhibited greater activity towards converting lipids for example MoZSM-5 enhanced the formation of aromatic compounds. NiZSM-5 and CuZSM-5 were observed to be more efficient for deoxygenation.

  17. Stability and Activity of Doped Transition Metal Zeolites in the Hydrothermal Processing

    International Nuclear Information System (INIS)

    Robin, Thomas François; Ross, Andrew B.; Lea-Langton, Amanda R.; Jones, Jenny M.

    2015-01-01

    This study investigates the stability and activity of HZSM-5 doped with metals such as molybdenum, nickel, copper, and iron under hydrothermal conditions used for the direct liquefaction of microalgae. Catalysts have been prepared by ion-exchange techniques, and MoZSM-5 was also prepared by wet incipient impregnation for comparison. Hydrothermal liquefaction is considered a potential route to convert microalgae into a sustainable fuel. One of the drawbacks of this process is that the bio-crude produced contains significant levels of nitrogen and oxygen compounds that have an impact on the physical and chemical properties of the fuel. Heterogeneous catalysts have been shown to improve the quality of the bio-crude by reducing nitrogen and oxygen contents. Zeolites, such as HZSM-5, are strong candidates due to their low cost compared to noble metal catalysts, but their stability and activity under hydrothermal conditions are not well understood. The stability of the catalysts has been determined under hydrothermal conditions at 350°C. Catalysts have been characterized before and after treatment using X-ray diffraction, BET physisorption, and scanning transmission electronic microscopy. Metal leaching was determined by the analysis of the water phase following the hydrothermal treatment. The inserted cation following ion-exchange can influence the physical properties of HZSM-5, for example, molybdenum improves the crystallinity of the zeolite. In general, metal-doped zeolites were relatively stable in subcritical water. The activity of the catalysts for processing lipids, protein, and microalgae has been assessed. Four feedstocks were selected: sunflower oil, soya proteins, Chlorella, and Pseudochoricystis ellipsoidea. The catalysts exhibited greater activity toward converting lipids, for example, MoZSM-5 enhanced the formation of aromatic compounds. NiZSM-5 and CuZSM-5 were observed to be more efficient for deoxygenation.

  18. Stability and Activity of Doped Transition Metal Zeolites in the Hydrothermal Processing

    Energy Technology Data Exchange (ETDEWEB)

    Robin, Thomas François, E-mail: thomas.cognac@gmail.com; Ross, Andrew B.; Lea-Langton, Amanda R.; Jones, Jenny M. [School of Chemical and Process Engineering, University of Leeds, Leeds (United Kingdom)

    2015-12-14

    This study investigates the stability and activity of HZSM-5 doped with metals such as molybdenum, nickel, copper, and iron under hydrothermal conditions used for the direct liquefaction of microalgae. Catalysts have been prepared by ion-exchange techniques, and MoZSM-5 was also prepared by wet incipient impregnation for comparison. Hydrothermal liquefaction is considered a potential route to convert microalgae into a sustainable fuel. One of the drawbacks of this process is that the bio-crude produced contains significant levels of nitrogen and oxygen compounds that have an impact on the physical and chemical properties of the fuel. Heterogeneous catalysts have been shown to improve the quality of the bio-crude by reducing nitrogen and oxygen contents. Zeolites, such as HZSM-5, are strong candidates due to their low cost compared to noble metal catalysts, but their stability and activity under hydrothermal conditions are not well understood. The stability of the catalysts has been determined under hydrothermal conditions at 350°C. Catalysts have been characterized before and after treatment using X-ray diffraction, BET physisorption, and scanning transmission electronic microscopy. Metal leaching was determined by the analysis of the water phase following the hydrothermal treatment. The inserted cation following ion-exchange can influence the physical properties of HZSM-5, for example, molybdenum improves the crystallinity of the zeolite. In general, metal-doped zeolites were relatively stable in subcritical water. The activity of the catalysts for processing lipids, protein, and microalgae has been assessed. Four feedstocks were selected: sunflower oil, soya proteins, Chlorella, and Pseudochoricystis ellipsoidea. The catalysts exhibited greater activity toward converting lipids, for example, MoZSM-5 enhanced the formation of aromatic compounds. NiZSM-5 and CuZSM-5 were observed to be more efficient for deoxygenation.

  19. Characterization of UO22+ exchanged Y zeolite

    International Nuclear Information System (INIS)

    Olguin, M.T.; Bosch, P.; Bulbulian, S.; Duque, J.; Pomes, R.; Villafuerte-Castrejon, M.E.; Sansores, L.E.; Bosch, P.

    1997-01-01

    The present study discusses the incorporation of uranyl ion into Y-zeolite framework. The UO 2 2+ sorption was measured by neutron activation analyses. The Y-zeolite framework distorts in response to the cations present in the structure. Hence, depending on the amount and the location of the exchanged cations, the features of the X-ray diffraction pattern may vary. From the Rietveld analysis of these patterns, the positions occupied by the UO 2 2 + cations in the zeolite network were determined. (author)

  20. Influencing the selectivity of zeolite Y for triglycine adsorption

    NARCIS (Netherlands)

    Wijntje, R.; Bosch, H.; Haan, A.B. de; Bussmann, P.J.T.

    2007-01-01

    In prior work we studied the adsorption of triglycine on zeolite Y under reference conditions. This study aims to solve the question of which adsorbent properties and process conditions influence the adsorption triglycine from an aqueous solution by zeolite Y. Relevant zeolite parameters to study

  1. Modification of textural and acidic properties of -SVR zeolite by desilication

    Czech Academy of Sciences Publication Activity Database

    Kubů, Martin; Opanasenko, Maksym; Shamzhy, Mariya

    2014-01-01

    Roč. 227, MAY 2014 (2014), s. 26-32 ISSN 0920-5861 R&D Projects: GA ČR GP13-17593P Institutional support: RVO:61388955 Keywords : -SVR zeolite * desilication * hierarchical materials Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 3.893, year: 2014

  2. Catalytic transformation of methyl benzenes over zeolite catalysts

    KAUST Repository

    Al-Khattaf, S.

    2011-02-01

    Catalytic transformation of three methyl benzenes (toluene, m-xylene, and 1,2,4-trimethyl benzene) has been investigated over ZSM-5, TNU-9, mordenite and SSZ-33 catalysts in a novel riser simulator at different operating conditions. Catalytic experiments were carried out in the temperature range of 300-400 °C to understand the transformation of these alkyl benzenes over large pore (mordenite and SSZ-33) in contrast to medium-pore (ZSM-5 and TNU-9) zeolite-based catalysts. The effect of reaction conditions on the isomerization to disproportionation product ratio, distribution of trimethylbenzene (TMB) isomers, and p-xylene/o-xylene ratios are reported. The sequence of reactivity of the three alkyl benzenes depends upon the pore structure of zeolites. The zeolite structure controls primarily the diffusion of reactants and products while the acidity of these zeolites is of a secondary importance. In the case of medium pore zeolites, the order of conversion was m-xylene > 1,2,4-TMB > toluene. Over large pore zeolites the order of reactivity was 1,2,4-TMB > m-xylene > toluene for SSZ-33 catalyst, and m-xylene ∼ 1,2,4-TMB > toluene over mordenite. Significant effect of pore size between ZSM-5 and TNU-9 was observed; although TNU-9 is also 3D 10-ring channel system, its slightly larger pores compared with ZSM-5 provide sufficient reaction space to behave like large-pore zeolites in transformation of aromatic hydrocarbons. We have also carried out kinetic studies for these reactions and activation energies for all three reactants over all zeolite catalysts under study have been calculated. © 2011 Elsevier B.V.

  3. Progressive Classification Using Support Vector Machines

    Science.gov (United States)

    Wagstaff, Kiri; Kocurek, Michael

    2009-01-01

    An algorithm for progressive classification of data, analogous to progressive rendering of images, makes it possible to compromise between speed and accuracy. This algorithm uses support vector machines (SVMs) to classify data. An SVM is a machine learning algorithm that builds a mathematical model of the desired classification concept by identifying the critical data points, called support vectors. Coarse approximations to the concept require only a few support vectors, while precise, highly accurate models require far more support vectors. Once the model has been constructed, the SVM can be applied to new observations. The cost of classifying a new observation is proportional to the number of support vectors in the model. When computational resources are limited, an SVM of the appropriate complexity can be produced. However, if the constraints are not known when the model is constructed, or if they can change over time, a method for adaptively responding to the current resource constraints is required. This capability is particularly relevant for spacecraft (or any other real-time systems) that perform onboard data analysis. The new algorithm enables the fast, interactive application of an SVM classifier to a new set of data. The classification process achieved by this algorithm is characterized as progressive because a coarse approximation to the true classification is generated rapidly and thereafter iteratively refined. The algorithm uses two SVMs: (1) a fast, approximate one and (2) slow, highly accurate one. New data are initially classified by the fast SVM, producing a baseline approximate classification. For each classified data point, the algorithm calculates a confidence index that indicates the likelihood that it was classified correctly in the first pass. Next, the data points are sorted by their confidence indices and progressively reclassified by the slower, more accurate SVM, starting with the items most likely to be incorrectly classified. The user

  4. PREPARASI DAN KARAKTERISASI ZEOLIT DARI ABU LAYANG BATUBARA SECARA ALKALI HIDROTERMAL

    Directory of Open Access Journals (Sweden)

    Jumaeri Jumaeri

    2012-01-01

    Full Text Available Preparasi zeolit dari abu layang batubara PLTU Suralaya secara alkali hidrotermal telah dilakukan. Preparasi dilakukan terhadap abu layang yang telah direfluks dengan HCl 1M dan tanpa refluks. Larutan NaOH dengan konsentrasi tertentu ( 1 ; 2 dan 3 M dicampur dengan abu layang batu bara dengan rasio 10 ml larutan tiap 1 gram abu layang, ke dalam tabung Teflon 100 ml dalam suatu autoclave stainless-steel. Autoclave kemudian dipanaskan pada temperature 80-16 oC selama tiga hari. Zeolit sintesis yang dihasilkan selanjutnya diuji secara kualitatif dengan menggunakan Spektroskopi Inframerah, dan Difraksi Sinar-X. Hasil penelitian menunjukkan bahwa aktivasi abu layang dengan proses alkali hidrotermal dapat menghasilkan material yang mempunyai struktur mirip zeolit (zeolit-like. Produk hidrotermal terdiri dari campuran zeolit (Zeolit P, Zeolit Y serta kristal sodalit dan mullit. Pada temperatur 160 oC, diperoleh zeolit dengan kristalinitas lebih tinggi dari pada 100 oC, baik melalui refluks atau tanpa refluks. Karakteristik zeolit yang terbentuk sangat ditentukan oleh kondisi proses, yang meliputi konsentrasi NaOH, waktu, dan temperatur.

  5. Basic deposits of zeolites of the Republic of Tajikistan

    International Nuclear Information System (INIS)

    Normatov, I.Sh.; Mirsaidov, U.M.

    2003-01-01

    Natural zeolites increasingly using in the different fields of human economical activity. As a result of investigations of last years was determined that zeolites are the wide-spread rock forming minerals. In the Republic of Tajikistan zeolites was found out an the north of the Republic

  6. Stability of glucose oxidase and catalase adsorbed on variously activated 13X zeolite.

    Science.gov (United States)

    Pifferi, P G; Vaccari, A; Ricci, G; Poli, G; Ruggeri, O

    1982-10-01

    The use of 13X zeolite (0.1-0.4-mm granules), treated with 2N and 0.01N HCI, 0.01M citric acid, 0.1M citric-phosphate buffer (pH 3.6), and in untreated form to adsorb glucose oxidase of fungal origin and microbial catalase was examined. Physicochemical analysis of the support demonstrated that its crystalline structure, greatly altered by the HCl and buffer, could be partially maintained with citric acid. The specific adsorption of the enzymes increased with decreasing pH and proved to be considerable for all the supports. The stability with storage at 25 degrees C is strictly correlated with the titrable acidity of the activated zeolite expressed as meq NaOH/g and with pH value of the activation solution. It proved to be lower than 55 h for both enzymes if adsorbed on zeolite treated with 2N HCl, and 15-fold and 30-fold higher for glucose oxidase and catalase adsorbed, respectively, on zeolite treated with the 0.1M citric-phosphate buffer and 0.01M citric acid. The specific adsorption of glucose oxidase and catalase was, respectively, 1840 U/g at pH 3.0 and 6910 U/g at pH 5.0. Their half-life at 25 degrees C with storage at pH 3.5 for the former and at pH 5.0 for the latter was 800 and 1560 h vs. 40 and 110 h for the corresponding free enzymes.

  7. Popular support for progressive taxation

    OpenAIRE

    Marhuenda Hurtado, Francisco; Ortuño Ortín, Ignacio Isidro

    1995-01-01

    The popular support obtained by two parties who propose two qualitatively different tax schernes is analyzed. We show that if the median voter is below the mean, then any progressive proposal always wins over a regressive one, provided it leaves the poorest agent at least as well off as the latter does.

  8. Influence of the Support of Copper Catalysts on Activity and 1,2-dichloroethane Selectivity in Ethylene Oxychlorination.

    Czech Academy of Sciences Publication Activity Database

    Vajglová, Zuzana; Kumar, N.; Eränen, K.; Tokarev, A.; Peurla, M.; Peltonen, J.; Murzin, D.Yu.; Salmi, T.

    2018-01-01

    Roč. 556 (2018), s. 41-51 ISSN 0926-860X Institutional support: RVO:67985858 Keywords : oxychlorination * copper * support effect Subject RIV: CI - Industrial Chemistry, Chemical Engineering OBOR OECD: Chemical process engineering Impact factor: 4.339, year: 2016

  9. Polyphosphates substitution for zeolite to in detergents

    International Nuclear Information System (INIS)

    Restrepo V, Gloria M.; Ocampo G, Aquiles; Saldarriaga M, Carlos

    1996-01-01

    The detergents, as well as the cleaning products, contain active ingredients that are good to increase their efficiency and some of them, as the sodium Tripoli-phosphate (TPF), they have turned out to be noxious for the environment. The zeolites use in the formulation of detergents has grown substantially since they fulfill the same function of the TPF and they have been recommended ecologically as substitutes from these when not being polluting. The objective of this work is to obtain a zeolite with appropriate characteristics for its use in the formulation of detergents, reproducing those of the zeolites used industrially. The zeolite synthesis is studied 4A starting from hydro-gels of different composition, varying the operation conditions and using two raw materials: (sodium meta-silicate, commercial degree and metallic aluminum) and clay type kaolin like silica source and aluminum It is looked for to get a product of beveled cubic morphology, or spherical, with glass size between 1 and 3 microns and that it possesses good capacity of conical exchange. Since the capacity and speed of ionic exchange is influenced by the particle size, time of contact and temperature, experimentation conditions settle down to measure the exchange of ions calcium and magnesium in watery solutions that they simulate the real situation of a laundry process in the country. This way the ability of the zeolite 4A obtained to diminish the concentration of these ions in the laundry waters is evaluated and its possibilities like component in the formulation of detergents non-phosphatates. Of the synthesized zeolites, the best in agreement is chosen with chemical properties as ionic and physical exchange capacity as crystalline, particle size and color, to prepare a detergent in which the polyphosphates is substituted partial and totally for the synthesized zeolite

  10. Potential Applications of Zeolite Membranes in Reaction Coupling Separation Processes

    Directory of Open Access Journals (Sweden)

    Tunde V. Ojumu

    2012-10-01

    Full Text Available Future production of chemicals (e.g., fine and specialty chemicals in industry is faced with the challenge of limited material and energy resources. However, process intensification might play a significant role in alleviating this problem. A vision of process intensification through multifunctional reactors has stimulated research on membrane-based reactive separation processes, in which membrane separation and catalytic reaction occur simultaneously in one unit. These processes are rather attractive applications because they are potentially compact, less capital intensive, and have lower processing costs than traditional processes. Therefore this review discusses the progress and potential applications that have occurred in the field of zeolite membrane reactors during the last few years. The aim of this article is to update researchers in the field of process intensification and also provoke their thoughts on further research efforts to explore and exploit the potential applications of zeolite membrane reactors in industry. Further evaluation of this technology for industrial acceptability is essential in this regard. Therefore, studies such as techno-economical feasibility, optimization and scale-up are of the utmost importance.

  11. CaE-T zeolite - a new effective adsorber for vacuum technique

    International Nuclear Information System (INIS)

    Skvazyvaev, V.E.; Khvoshchev, S.S.; Zhdanov, S.P.

    1975-01-01

    Adsorption of air at low pressures on type E zeolites was studied as a function of their composition and dehydration regime. It was shown that zeolite CaE-T has a greatly increased sorption capacity for air at low pressures and that this is more than 3 times that of industrial zeolites currently used in vacuum technology. Mass-spectrometer studies were made of the gas phase over zeolites type E and A after adsorption of air at pressures from 10 -8 to 10 -5 mm Hg at liquid nitrogen temperatures under conditions approximating equilibrium. It was shown that zeolite CaE-T has a high adsorption capacity for Ar, O 2 , and H 2 . Adsorption of H 2 and Ar by zeolites of different structural types at low pressures was studied. It was shown that zeolite CaE-T has a significantly higher adsorption capacity for hydrogen and argon than all industrial zeolites

  12. Fixing noble gas in zeolites

    International Nuclear Information System (INIS)

    Rocha Dorea, A.L. da.

    1980-09-01

    In order to increase safety during the long-term storage of Kr-85 it has been proposed to encaosulate this gas in zeolite 5A. Due to the decay heat of Kr-85 it is expected, however, that the inorganic matrix will be at an increased temperature over several decades. Below 600 0 C only very small Kr-desorption rates are observed when a linear temperature gradient is applied to a loaded 5A zeolite sample. If heating is interrupted and the temperature kept konstant at a certain value (>600 0 C), it is observed that the desorption rate either decreased below the detection limit or stayed constant at some measurable value. The overall activation energy in the temperature range 570 0 C-745 0 C is found to be 250 kJ/mol. At temperature above 790 0 C the total encapsulated gas is rapidly liberated. No significant leakage was apparent from zeolite 5A samples containing between 19 and 57 cm 3 STP Kr/g kept at 200 0 C for up to 2500 h and 400 0 C for up to 3500 h. From these studies it is found that type 5A zeolites are particularly suitable as a matrix for the inmobilization of Kr-85. (Author) [pt

  13. Ultrasonic vs hydrothermal method: Different approaches to convert fly ash into zeolite. How they affect the stability of synthetic products over time?

    Science.gov (United States)

    Belviso, Claudia

    2018-05-01

    The action of direct sonication (US) versus conventional hydrothermal method (HY) was investigated to determine the differences in the crystallization mechanism of zeolite formed from fly ash. The results showed that ultrasonic energy is decisive in very fast faujasite and A-type zeolite transformation into more stable sodalite phase. The data display the main presence of sodalite together with a low amount of faujasite and zeolite A after the first 3 h of sonication. The full transformation of the latter two phases into sodalite takes place after 1 h more of treatment. The samples incubated by hydrothermal process for 3 h, instead, are characterized by the main presence of faujasite and A-type zeolites. The progressive synthesis of sodalite at the expense of the other two phases begins only after 4 h of treatment. The conclusion is that the crystallization of zeolites by ultrasonic and hydrothermal method proceeds via two different mechanisms. The data also show that the two approaches affect the stability of the synthetic products in a different way over the years. Copyright © 2017 Elsevier B.V. All rights reserved.

  14. Recent Advances on Bioethanol Dehydration using Zeolite Membrane

    Science.gov (United States)

    Makertihartha, I. G. B. N.; Dharmawijaya, P. T.; Wenten, I. G.

    2017-07-01

    Renewable energy has gained increasing attention throughout the world. Bioethanol has the potential to replace existing fossil fuel usage without much modification in existing facilities. Bioethanol which generally produced from fermentation route produces low ethanol concentration. However, fuel grade ethanol requires low water content to avoid engine stall. Dehydration process has been increasingly important in fuel grade ethanol production. Among all dehydration processes, pervaporation is considered as the most promising technology. Zeolite possesses high potential in pervaporation of bioethanol into fuel grade ethanol. Zeolite membrane can either remove organic (ethanol) from aqueous mixture or water from the mixture, depending on the framework used. Hydrophilic zeolite membrane, e.g. LTA, can easily remove water from the mixture leaving high ethanol concentration. On the other hand, hydrophobic zeolite membrane, e.g. silicate-1, can remove ethanol from aqueous solution. This review presents the concept of bioethanol dehydration using zeolite membrane. Special attention is given to the performance of selected pathway related to framework selection.

  15. Synthesis and characterization of zeolite material from coal ashes modified by surfactant

    International Nuclear Information System (INIS)

    Fungaro, D.A.; Borrely, S.I.

    2010-01-01

    Coal ash was used as starting material for zeolite synthesis by means of hydrothermal treatment. The surfactant-modified zeolite (SMZ) was prepared by adsorbing the cationic surfactant hexadecyltrimethylammonium bromide (HDTMA-Br) on the external surface of the zeolite from coal ash. The zeolite structure stability was monitored during the characterization of the materials by FTIR, XDR and SEM. The structural parameters of surfactant-modified zeolite are very close to that of corresponding non-modified zeolite which indicates that the crystalline nature of the zeolite remained intact after required chemical treatment with HDTMA-Br molecules and heating treatment for drying. The most intense peaks in the FTIR spectrum of HDTMA-Br were observed in SMZ spectrum confirming adsorption of surfactant on zeolites. (author)

  16. CuY zeolite catalysts prepared by ultrasonication-assisted ion-exchange for oxidative carbonylation of methanol to dimethyl carbonate.

    Science.gov (United States)

    Woo, Je-Min; Seo, Jung Yoon; Kim, Hyunuk; Lee, Dong-Ho; Park, Young Cheol; Yi, Chang-Keun; Park, Yeong Seong; Moon, Jong-Ho

    2018-06-01

    The influence of ultrasonication treatment on the catalytic performance of CuY zeolite catalysts was investigated for the liquid-phase oxidative carbonylation of methanol to dimethyl carbonate (DMC). The deammoniation method of NH 4 Y into HY zeolites was optimized and characterized by elemental analyzer, derivative thermogravimetry, Brunauer-Emmett-Teller (BET) analyzer, and powder X-ray diffractometry, revealing that the HY zeolite deammoniated at 400 °C presented the highest surface area, complete ammonium/proton ion exchange, and no structure collapse, rendering it the best support from all the prepared zeolites. CuY zeolites were prepared via aqueous phase ion exchange with the aid of ultrasonication. Upon ultrasonication, the Cu + active centers were uniformly dispersed in the Y zeolites, penetrating the core of the zeolite particles in a very short time. In addition to enhancing the Cu dispersity, the ultrasonication treatment influenced the BET surface area, acid amount, Cu + /Cu 2+ ratio, and also had a relatively small impact on the Cu loading. Consequently, adequate exposure to ultrasonication was able to increase the conversion rate of methanol into dimethyl carbonate up to 11.4% with a comparable DMC selectivity of 23.7%. This methanol conversion is 2.65 times higher than that obtained without the ultrasonication treatment. Copyright © 2018 Elsevier B.V. All rights reserved.

  17. Investigation of zeolites by solid state quadrapole NMR

    International Nuclear Information System (INIS)

    Janssen, R.

    1990-01-01

    The subject of this thesis is the NMR investigation of zeolites. The nature and properties of zeolites are discussed. Some of the basic priniples of NMR techniques on quadrupole nuclei are presented. A special technique, namely a two-dimensional nutation experiment is discussed in detail. The theory of the nutation experiment for quadrupole spin species with spin quantum number 3/2 as well as 5/2 is presented. For both spin spcies the theoretical spectra are compared with experimental results. It is also shown that the nutation expeirment can be performed with several pulse schemes. It is shown how phase-sensitive pure-absorption nutation spectra can be obtained and an NMR-probe is presented that is capable of performing NMR experiments at high (up to 500 degree C) temperatures. The two-dimensional nutation NMR technique has been applied to sodium cations in zeolite NaA. For this purpose a numbre of zeolite samples were prepared that contained different amounts of water. With the aid of nutation NMR the hydration of the zeolite can be studied and conclusions can be drawn about the symmetry of the surrounding of the sodium cations. With the aid of an extension of the nutation NMR experiment: Rotary Echo Nutation NMR, it is shown that in zeolite NaA, in various stages of hydration, the sodium cations or water molecules are mobile. Proof is given by means of high-temperature 23 Na-NMR that dehydrates zeolite NaA undergoes a phase transition at ca. 120 degree C. In a high-temperature NMR investigation of zeolite ZSM-5 it is shown that the sodium ions start to execute motions when the temperature is increased. (author). 198 refs.; 72 figs.; 6 tabs

  18. Modificação de zeólitas para uso em catálise Modifying zeolites for use in catalysis

    Directory of Open Access Journals (Sweden)

    Fernando J. Luna

    2001-12-01

    Full Text Available The use of zeolites and other molecular sieves as catalysts is discussed at an introductory level. The text includes a brief historic background on the use of zeolites in catalysis, and a discussion of some chemical and physical properties of silicalite, aluminosilicate, and aluminophosphate molecular sieves. The strategies currently used to chemically modify zeolites and related materials to produce catalysts with increased activity and selectivity are discussed, including the use of redox molecular sieves for hydrocarbon oxidation and the leaching of the active metals from the support.

  19. Multicolor photoluminescence in ITQ-16 zeolite film

    KAUST Repository

    Chen, Yanli; Dong, Xinglong; Zhang, Zhenyu; Feng, Lai

    2016-01-01

    Exploring the native defects of zeolites is highly important for understanding the properties of zeolites, such as catalysis and optics. Here, ITQ-16 films were prepared via the secondary growth method in the presence of Ge atoms. Various intrinsic

  20. Study of 63Ni adsorption on NKF-6 zeolite

    International Nuclear Information System (INIS)

    Zhang Hui; Yu Xianjin; Chen Lei; Jing Yongjie; Ge Zhiwei

    2010-01-01

    The adsorption of 63 Ni from aqueous solutions using NKF-6 zeolite was investigated by a batch technique under ambient conditions. The adsorption was investigated as a function of contact time, pH, ionic strength, foreign ions, humic substances (FA/HA) and temperature. The kinetic adsorption was well described by the pseudo-second-order rate equation. The adsorption of 63 Ni on NKF-6 zeolite was strongly dependent on pH and ionic strength, and the adsorption of 63 Ni increased with increasing NKF-6 zeolite content. At low pH values, the presence of FA enhanced the adsorption of 63 Ni on NKF-6 zeolite, but the presence of HA had no drastic effect. At high pH values, the presence of FA or HA decreased the adsorption of 63 Ni on NKF-6 zeolite. The adsorption isotherms were well represented by the Langmuir model. The thermodynamic parameters (i.e., ΔH 0 , ΔS 0 and ΔG 0 ) for the adsorption of 63 Ni were determined from the temperature dependent isotherms at 293.15, 313.15 and 333.15 o K, respectively, and the results indicate that the adsorption reaction was favored at high temperature. The results suggest that the adsorption process of 63 Ni on NKF-6 zeolite is spontaneous and endothermic. - Research highlights: → As an economical and efficient method, adsorption technique has been widely applied in the disposal of wastewaters. The study of 63 Ni on NKF-6 zeolite, especially the thermodynamic data of 63 Ni adsorption on NKF-6 zeolite and the effect of humic substances on 63 Ni uptake to humic-zeolite hybrids, is still scarce. In this paper, the sorption of 63 Ni on NKF-6 zeolite is studied as a function of various environmental conditions such as contact time, pH, ionic strength, foreign ions, humic substances and temperature. Based on the obtained experimental results, the adsorption mechanism of 63 Ni on NKF-6 zeolite is stated in detail. This study will have an important reference value in evaluating the physiochemical behavior of radionuclide 63 Ni.

  1. Zeolites and clays behavior in presence of radioactive solutions

    International Nuclear Information System (INIS)

    Carrera Garcia, L.M.

    1991-01-01

    Natural aluminosilicates have found application as selective ion exchangers for radioactive cations, present in liquid wastes arising from nuclear facilities. Among severals cations and complex mixtures of them, Co is a common constituent of liquid radioactive wastes. Two types of zeolites (Y zeolite, and natural mexican erionite), and two types of clays (natural bentonite, and Al-expanded bentonite (Al-B) were used. Previous to the experiments, the zeolites and the natural bentonite were stabilized to their respective Na + form using 5N NaCl solution. 2Na + → 60 Co 2+ ion exchange kinetics in zeolites and clays was followed by gamma spectrometry using a NaCl-Co(NO 3 ) 2 isonormal solution (0.1N) labeled with 60 Co-Co(NO 3 ) 2 (100 μ Ci). Before and after experiments, the structural changes in the cristallinity of aluminosilicates were determined by X-ray diffraction. XRD analyzes show that the cristallinity of the aluminosilicates was not affected by ion exchange. After Co exchange the cell parameters were determined in all samples. The efficiency of zeolites, natual clays and expanded clays to remove cobalt ions from solutions depends on the ion echange capacity of the material. Results for long contacts time, 18 days, show that Co is more effectively removed by Y zeolite ( 4.07 wt %), followed by erionite (3.09 wt %), then bentonite ( 2.36 wt %) and finally expanded bentonite ( 0.70 wt %). In Y zeolite an unusual fast soportion uptake of 4.51 % wt Co was observed followed by a desorption process to 4.07 %. This effect is due to the different hydration degree of zeolites during the contact time between the zeolite and the 60 Co solution. In erionite the exchange is lower than in Y-zeolite, frist because the Si/Al ratio is higher for erionite than for Y-zeolite and second because K ions in erionite cannot be exchanged during the stabilization of erionite in 5N NaCl solution. The low exchange in expanded bentonite was expected because its cation exchange

  2. Performance of zeolite scavenge column in Xe monitoring system

    International Nuclear Information System (INIS)

    Wang Qian; Wang Hongxia; Li Wei; Bian Zhishang

    2010-01-01

    In order to improve the performance of zeolite scavenge column, its ability of removal of humidity and carbon dioxide was studied by both static and dynamic approaches. The experimental results show that various factors, including the column length and diameter, the mass of zeolite, the content of water in air, the temperature rise during adsorption, and the activation effectiveness all effect the performance of zeolite column in scavenging humanity and carbon dioxide. Based on these results and previous experience, an optimized design of the zeolite column is made for use in xenon monitoring system. (authors)

  3. Zeolites with continuously tuneable porosity

    OpenAIRE

    Wheatley, Paul S; Chlubná-Eliášová, Pavla; Greer, Heather; Zhou, Wuzong; Seymour, Valerie R; Dawson, Daniel M; Ashbrook, Sharon E; Pinar, Ana B; McCusker, Lynne B; Opanasenko, Maksym; Cejka, Jiří; Morris, Russell E

    2014-01-01

    Czech Science Foundation. Grant Number: P106/12/G015 Zeolites are important materials whose utility in industry depends on the nature of their porous structure. Control over microporosity is therefore a vitally important target. Unfortunately, traditional methods for controlling porosity, in particular the use of organic structure-directing agents, are relatively coarse and provide almost no opportunity to tune the porosity as required. Here we show how zeolites with a continuously tuneabl...

  4. Preparation of 13X from Waste Quartz and Photocatalytic Reaction of Methyl Orange on TiO2/ZSM-5, 13X and Y-Zeolite.

    Science.gov (United States)

    Wang, Jia-Jie; Jing, You-Hai; Ouyang, Tong; Chang, Chang-Tang

    2015-08-01

    TiO2 photocatalytic reactions not only remove a variety of organic pollutants via complete mineralization, but also destroy the bacterial cell wall and cell membrane, thus playing an important bactericidal role. However, the post-filtration procedures to separate nanometer-levels of TiO2 and the gradual inactivity of photocatalyst during continuous use are defects that limit its application. In this case, we propose loading TiO2 on zeolite for easy separation and 13X is considered as a promising one. In our study, 13X-zeolite was prepared by a hydrothermal method and the source of Si was extracted from waste quartz sand. For comparison, commercial zeolite with different microporous and mesoporous diameters (ZSM-5 and Y-zeolites) were also used as TiO2 supports. The pore size of the three kinds of zeolites are as follows: Y-zeolite > 13X > ZSM-5. Different TiO2 loading content over ZSM-5, 13X and Y-zeolite were prepared by the sol-gel method. XRD, FTIR, BET, UV-vis, TGA and SEM were used for investigation of material characteristics. In addition, the efficiencies of mineralization and photodegradation were studied in this paper. The effects of the loading ratio of TiO2 over zeolites, initial pH, and concentration on photocatalytic performance are investigated. The relationship between best loading content of TiO2 and pore size of the zeolite was studied. The possible roles of the ZSM-5, 13X-zeolites and Y-zeolites support on the reactions and the possible mechanisms of effects were also explored. The best loading content of TiO2 over ZSM-5, 13X and Y-zeolite was found to be 50 wt%, 12.5 wt% and 7 wt%, respectively. The optimum pH condition is 3 with TiO2 over ZSM-5, 13X-zeolites and Y-zeolites. The results showed that the degradation and mineralization efficiency of 12.5 wt%GT13X (TiO2 over 13X) after 90 min irradiation reached 57.9% and 22.0%, which was better than that of 7 wt%GTYZ (TiO2 over Y-zeolites) while much lower than that of 50 wt%GTZ (TiO2 over ZSM-5

  5. Impact of steel slag on the ammonium adsorption by zeolite and a new configuration of zeolite-steel slag substrate for constructed wetlands.

    Science.gov (United States)

    Shi, Pengbo; Jiang, Yingbo; Zhu, Hongtao; Sun, Dezhi

    2017-07-01

    The CaO dissolution from slag, as well as the effects of influencing parameters (i.e. pH and Ca 2+ concentration) on the ammonium adsorption onto zeolite, was systematically studied in this paper. Modeling results of Ca 2+ and OH - release from slag indicated that pseudo-second-order reaction had a better fitness than pseudo-first-order reaction. Changing pH value from 7 to 12 resulted in a drastic reduction of the ammonium adsorption capacity on zeolite, from the peak adsorption capacity at pH 7. High Ca 2+ concentration in solution also inhibited the adsorption of ammonium onto zeolite. There are two proposed mechanisms for steel slag inhibiting the ammonium adsorption capacity of zeolite. On the one hand, OH - released from steel slag can react with ammonium ions to produce the molecular form of ammonia (NH 3 ·H 2 O), which would cause the dissociation of NH 4 + from zeolite. On the other hand, Ca 2+ could replace the NH 4 + ions to adhere onto the surface of zeolite. An innovative substrate filling configuration with zeolite placed upstream of the steel slag was then proposed to eliminate the disadvantageous effects of steel slag. Experimental results showed that this novel filling configuration was superior to two other filling configurations in terms of ammonium removal.

  6. Effects of Zeolite (Clinoptelolite on Performance Characteristics of

    Directory of Open Access Journals (Sweden)

    A Hassan Abadim

    2011-12-01

    Full Text Available A 70-days experiment was conducted to investigate the effects of natural zeolite (clinoptelolite on the performance of commercial laying hens. 288 Hy-Line W36 strain laying hens (50 weeks old were allotted to 6 dietary treatments including basal diet as control and basal diet supplemented with 1, 2, 3, 4 and 5% zeolite that were fed ad -libitum throughout the experiment. Experimental diets for the 6 treatments were prepared to be iso-caloric and iso-nitrogenous. A completely randomized design with six treatments, eight replicates of six birds per replicate was used at this experiment. Daily feed intake (DFI, feed conversion ratio (FCR, egg production, egg weight, egg white quality, eggshell quality (thickness and percentage and body weight changes were measured during the experiment. Results of this experiment showed that DFI, FCR, egg production and egg abnormality were not significantly (P>0.05 affected by zeolite supplementation. Zeolite supplementation significantly increased egg weight, eggshell thickness and live body weight gain of the hens. Dietary zeolite significantly decreased haugh unit of the eggs. In conclusion, natural zeolite significantly improved egg weight and eggshell quality, decreased haugh unit and live weight gain, and had no significant effects on other parameters.

  7. Synthesis and catalytic applications of combined zeolitic/mesoporous materials

    Directory of Open Access Journals (Sweden)

    Jarian Vernimmen

    2011-11-01

    Full Text Available In the last decade, research concerning nanoporous siliceous materials has been focused on mesoporous materials with intrinsic zeolitic features. These materials are thought to be superior, because they are able to combine (i the enhanced diffusion and accessibility for larger molecules and viscous fluids typical of mesoporous materials with (ii the remarkable stability, catalytic activity and selectivity of zeolites. This review gives an overview of the state of the art concerning combined zeolitic/mesoporous materials. Focus is put on the synthesis and the applications of the combined zeolitic/mesoporous materials. The different synthesis approaches and formation mechanisms leading to these materials are comprehensively discussed and compared. Moreover, Ti-containing nanoporous materials as redox catalysts are discussed to illustrate a potential implementation of combined zeolitic/mesoporous materials.

  8. Transformation of analcime into IMF structure during the synthesis of IMF zeolite

    Czech Academy of Sciences Publication Activity Database

    Kubů, Martin; Přech, Jan

    2015-01-01

    Roč. 206, APR 2015 (2015), s. 121-126 ISSN 1387-1811 R&D Projects: GA ČR GP13-17593P Institutional support: RVO:61388955 Keywords : IMF zeolite * analcime * crystallization Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 3.349, year: 2015

  9. Transformation of analcime into IMF structure during the synthesis of IMF zeolite

    Czech Academy of Sciences Publication Activity Database

    Kubů, Martin; Přech, Jan

    2015-01-01

    Roč. 206, C (2015), s. 121-126 ISSN 1387-1811 R&D Projects: GA ČR GP13-17593P Institutional support: RVO:61388955 Keywords : Analcime * Crystallization * IMF zeolite Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 3.349, year: 2015

  10. Nanostructured Ag-zeolite Composites as Luminescence-based Humidity Sensors

    Science.gov (United States)

    Dieu, Bjorn; Roeffaers, Maarten B.J.; Hofkens, Johan

    2016-01-01

    Small silver clusters confined inside zeolite matrices have recently emerged as a novel type of highly luminescent materials. Their emission has high external quantum efficiencies (EQE) and spans the whole visible spectrum. It has been recently reported that the UV excited luminescence of partially Li-exchanged sodium Linde type A zeolites [LTA(Na)] containing luminescent silver clusters can be controlled by adjusting the water content of the zeolite. These samples showed a dynamic change in their emission color from blue to green and yellow upon an increase of the hydration level of the zeolite, showing the great potential that these materials can have as luminescence-based humidity sensors at the macro and micro scale. Here, we describe the detailed procedure to fabricate a humidity sensor prototype using silver-exchanged zeolite composites. The sensor is produced by suspending the luminescent Ag-zeolites in an aqueous solution of polyethylenimine (PEI) to subsequently deposit a film of the material onto a quartz plate. The coated plate is subjected to several hydration/dehydration cycles to show the functionality of the sensing film. PMID:27911397

  11. Application of positron annihilation to the characterization of zeolites

    International Nuclear Information System (INIS)

    Nakanishi, H.; Ujihira, Y.

    1982-01-01

    Positron annihilation lifetime and Doppler-broadening measurements were carried out for synthetic zeolite 13X, SK-40, NH 4 -X, and NH 4 -Y by varying the evacuation temperature in order to study the character of the zeolite cages. Four components of the positron annihilation, derived from the lifetime spectra, were interpreted from the results of the authors' measurements and other studies on zeolites. The o-Ps lifetimes in the cages became longer as the desorption of water molecules proceeded. It was found that some active groups in zeolites interacted with o-Ps and reduced the o-Ps lifetime after all the water molecules had detected. Bronsted acid in the zeolite acted not only as an oxidizer but also as an inhibitor of Ps formation. An attempt was made to estimate the amount of Bronsted acids by the positron lifetime technique. The longest lifetime of 50 ns indicates o-Ps annihilation in a pore with 60 A free diameter, which seems to exist irregularly in the faujasite zeolites. It was found that o-Ps was oxidized in this large cavity

  12. Ageing and structural effects on the sorption characteristics of Cd2+ by clinoptilolite and Y-type zeolite studied using isotope exchange technique

    International Nuclear Information System (INIS)

    Ahmed, I.A.M.; Young, S.D.; Crout, N.M.J.

    2010-01-01

    This research investigates the long-term kinetics of Cd 2+ sorption and desorption by calcium-exchanged clinoptilolite (CaCpt) and Y-type (CaY) zeolite using isotopic exchange with 109 Cd while maintaining pH at circumneutral values. The effects of Si/Al ratio and crystal structure of these zeolitic materials on intracrystalline transport of Cd are discussed. A first-order kinetic model was developed to describe the progressive transfer of Cd 2+ to a less reactive form within the zeolite structure, following initial sorption and subsequent desorption of Cd subject to different initial contact times. The kinetic model differentiates between two forms of sorbed Cd 2+ designated 'labile' and 'non-labile' in which the labile form is in immediate equilibrium with the free Cd 2+ ion activity in solution. A model combining diffusion and first-order kinetics for cation exchange was also employed to determine Cd 2+ diffusivity and intracrystalline exchange rates in CaY and CaCpt. The efficiency of Permeable Reactive Barriers (PRBs) containing zeolitic materials in protecting water systems against lateral flow of metal-contaminated leachate was simulated for three contrasting zeolites. The slow transfer of Cd between labile and non-labile forms was particularly important in moderating high concentration pulses of Cd traversing the PRB. In addition, the reversibility of Cd fixation effectively restored the sorption capability of the zeolite through slow leakage to drainage water.

  13. Nonionic emulsion-mediated synthesis of zeolite beta

    Indian Academy of Sciences (India)

    Zeolite beta synthesis was first carried out in a newly developed emulsion system containing nonionic polyoxyethylated alkylphenol surfactant, which showed interesting non-conventional features. Compared to the conventional hydrothermal synthesis of zeolite beta, the reported nonionic emulsion system showed a faster ...

  14. Application of Zeolitic Additives in the Fluid Catalytic Cracking (FCC

    Directory of Open Access Journals (Sweden)

    A. Nemati Kharat

    2013-06-01

    Full Text Available Current article describes application of zeolites in fluid catalytic cracking (FCC. The use of several zeolitic additives for the production light olefins and reduction of pollutants is described. Application of zeolites as fluid catalytic cracking (FCC catalysts and additives due to the presence of active acid sites in the zeolite framework  increase the formation of desired cracking products (i.e., olefin and branched products  in the FCC unit.

  15. Effect of alkali-treatment on the characteristics of natural zeolites with different compositions.

    Science.gov (United States)

    Ates, Ayten

    2018-08-01

    A series of natural zeolites with different compositions were modified by post-synthesis modification with sodium hydroxide (NaOH) solution. Natural and modified zeolites were characterized by XRD, SEM, nitrogen adsorption, FTIR, zeta potential and temperature programmed desorption of ammonia (NH 3 -TPD). The adsorption capacities of these samples were evaluated by the adsorption of manganese from aqueous solution. The treatment with NaOH led to a decrease in the surface area and microporosity of all natural zeolites as well as partly damage of the zeolite structure depending on zeolite composition. In addition, the amount of weak, medium and strong acid sites in the zeolites was changed significantly by NaOH treatment depending on zeolite composition. The NaOH treatment resulted in a four-fold improvement in adsorption capacity of natural zeolite originated from Bigadic and a twofold decrease in that of the natural zeolite originated from Manisa-Gordes. Although the improved adsorption capacity might be mainly due to modification of porosity in the zeolites and formation of hydroxysodalite, the reduced adsorption capacity of the zeolite might be mainly due to a significant deformation of the zeolite structure. The pseudo-second-order kinetic model for the adsorption of manganese on all natural and modified zeolites fits well. Copyright © 2018 Elsevier Inc. All rights reserved.

  16. Annual Copper Mountain Conferences on Multigrid and Iterative Methods, Copper Mountain, Colorado

    International Nuclear Information System (INIS)

    McCormick, Stephen F.

    2016-01-01

    This project supported the Copper Mountain Conference on Multigrid and Iterative Methods, held from 2007 to 2015, at Copper Mountain, Colorado. The subject of the Copper Mountain Conference Series alternated between Multigrid Methods in odd-numbered years and Iterative Methods in even-numbered years. Begun in 1983, the Series represents an important forum for the exchange of ideas in these two closely related fields. This report describes the Copper Mountain Conference on Multigrid and Iterative Methods, 2007-2015. Information on the conference series is available at http://grandmaster.colorado.edu/~copper/

  17. Annual Copper Mountain Conferences on Multigrid and Iterative Methods, Copper Mountain, Colorado

    Energy Technology Data Exchange (ETDEWEB)

    McCormick, Stephen F. [Front Range Scientific, Inc., Lake City, CO (United States)

    2016-03-25

    This project supported the Copper Mountain Conference on Multigrid and Iterative Methods, held from 2007 to 2015, at Copper Mountain, Colorado. The subject of the Copper Mountain Conference Series alternated between Multigrid Methods in odd-numbered years and Iterative Methods in even-numbered years. Begun in 1983, the Series represents an important forum for the exchange of ideas in these two closely related fields. This report describes the Copper Mountain Conference on Multigrid and Iterative Methods, 2007-2015. Information on the conference series is available at http://grandmaster.colorado.edu/~copper/.

  18. A database of new zeolite-like materials.

    Science.gov (United States)

    Pophale, Ramdas; Cheeseman, Phillip A; Deem, Michael W

    2011-07-21

    We here describe a database of computationally predicted zeolite-like materials. These crystals were discovered by a Monte Carlo search for zeolite-like materials. Positions of Si atoms as well as unit cell, space group, density, and number of crystallographically unique atoms were explored in the construction of this database. The database contains over 2.6 M unique structures. Roughly 15% of these are within +30 kJ mol(-1) Si of α-quartz, the band in which most of the known zeolites lie. These structures have topological, geometrical, and diffraction characteristics that are similar to those of known zeolites. The database is the result of refinement by two interatomic potentials that both satisfy the Pauli exclusion principle. The database has been deposited in the publicly available PCOD database and in www.hypotheticalzeolites.net/database/deem/. This journal is © the Owner Societies 2011

  19. EFFECT OF GRAIN SIZE AND ACTIVATION TIME OF ZEOLITE TO ADSORPTION AND DESORPTION OF NH4OH AND KCL AS MODEL OF FERTILIZER-ZEOLITE MIX

    Directory of Open Access Journals (Sweden)

    Muhammad Prasantio Bimantio

    2017-10-01

    Full Text Available Zeolites can be used as adsorbent, ion exchange, catalyst, or catalyst carrier. Application of fertilizer use in the zeolite also be one of the interesting topic. Zeolites in a mixture of fertilizer can use to control the release of nutrients. The purpose of this research is to study the effect of grain size and time of the activation of zeolite to adsorption and desorption of NH4OH and KCl as modeling of ZA and KCl fertilizer, to obtain the value of adsorption rate constant (ka and desorption rate constant (kd. This research procedure include: the process of adsorption by adding zeolite with various size and time of activation into a sealed beaker glass and let the adsorption process occurs for 24 hours. After 24 hours, the solution was filtered, the zeolite then put in 100 ml of aquadest into a sealed beaker glass and let the desorption process happened for another 24 hours. Three samples with the largest difference solution concentrations looked for the value of the ka and kd. Zeolite configuration with the largest ka is trialed with fertilizer and compared with the value of ka obtained from modeling. The result for NH4OH adsorbate, -50+60 mesh 2 hours configuration zeolite give the largest ka. For KCl adsorbate, -30+40 mesh 4 hours configuration zeolite give the largest ka. The value between modeling and trials with fertilizers are not much different.

  20. Nanodispersed Suspensions of Zeolite Catalysts for Converting Dimethyl Ether into Olefins

    Science.gov (United States)

    Kolesnichenko, N. V.; Yashina, O. V.; Ezhova, N. N.; Bondarenko, G. N.; Khadzhiev, S. N.

    2018-01-01

    Nanodispersed suspensions that are effective in DME conversion and stable in the reaction zone in a three-phase system (slurry reactor) are obtained from MFI zeolite commercial samples (TsVM, IK-17-1, and CBV) in liquid media via ultrasonic treatment (UST). It is found that the dispersion medium, in which ultrasound affects zeolite commercial sample, has a large influence on particle size in the suspension. UST in the aqueous medium produces zeolite nanoparticles smaller than 50 nm, while larger particles of MFI zeolite samples form in silicone or hydrocarbon oils. Spectral and adsorption data show that when zeolites undergo UST in an aqueous medium, the acid sites are redistributed on the zeolite surface and the specific surface area of the mesopores increases. Preliminary UST in aqueous media of zeolite commercial samples (TsVM, IK-17-1, and CBV) affects the catalytic properties of MFI zeolite nanodispersed suspensions. The selectivity of samples when paraffins and olefins form is largely due to superacid sites consisting of OH groups of hydroxonium ion H3O+.

  1. Ion-exchange properties of cesium and strontium into zeolites from sodium salt solutions

    International Nuclear Information System (INIS)

    Kanno, Takuji; Hashimoto, Hiroyuki; Ohtani, Tozo.

    1978-01-01

    The ion-exchange properties of cesium and strontium into zeolite from sodium salt solution has been studied in zeolite A, zeolite X, zeolite Y, mordenite and clinoptilolite. The distribution of cesium into mordenite from about 1 -- 2 M sodium chloride and sodium hydroxide solutions is considerably larger than that into zeolite A. The distribution coefficient for 2 M solution of sodium salts was about 300. Therefore, the separation of cesium from sodium salt solution is possible by using mordenite. The distribution of strontium into zeolites form 1 -- 2 M solutions of sodium chloride and sodium nitrate were in the order of zeolite A>zeolite X>zeolite Y asymptoticaly equals mordenite. The distribution coefficient of 230 was obtained for 1 M solutions of sodium salts. The anion in solutions had no effect on the distribution of cesium and strontium into zeolite from sodium salt solution. (author)

  2. A structure study of copper oxide for monolayer dispersion of anatase supported

    International Nuclear Information System (INIS)

    Zi Fenlan; Yu Xiaofeng; Guo Hongyou; Cai Xiaohai; Yang Pengcheng; Wu Nianzu; Xie Yaning; Zang Jing; Hu Tiandou

    2002-01-01

    The monolayer dispersion of copper oxide on the surface of anatase and its effect on the properties have been studied by X-ray photoelectron spectroscopy (XPS) and X-ray extended absorption fine structure (EXAFS). XPS results give an utmost dispersion capacity of 7.2 mg/gTiO 2 . Strong interactions between copper oxide and anatase can be seen from EXAFS results. The structure of the supported CuO species is strongly dependent on the amount of CuO loading. When the content of CuO loading is below the utmost dispersion capacity, the surface of CuO/TiO 2 is dominated by the highly dispersed CuO species having no -Cu-O-Cu- chains. The copper ion is located in an octahedral coordination environment, and the Cu-O coordination distance is much longer than that in pure crystalline CuO. When CuO loading is exceeds the utmost dispersion capacity, crystalline CuO is formed on the surface of CuO/TiO 2 . From the result of the structure study, it is Cu-O octahedral coordination and coordination distance change in comparison with pure crystalline CuO on the surface CuO/TiO 2 that have catalytic activity

  3. Zeolite from fly ash: synthesis and characterization

    Indian Academy of Sciences (India)

    Coal fly ash was used to synthesize X-type zeolite by alkali fusion followed by hydrothermal treatment. The synthesized zeolite was characterized using various techniques such as X-ray diffraction, scanning electron microscopy, Fourier transform infrared spectroscopy, BET method for surface area measurement etc.

  4. Ni catalysts with different promoters supported on zeolite for dry reforming of methane

    KAUST Repository

    Alotaibi, Raja; Alenazey, Feraih; Alotaibi, Faisal; Wei, Nini; Al-Fatesh, Ahmed; Fakeeha, Anis

    2015-01-01

    Dry reforming of methane (DRM) is considered a high endothermic reaction with operating temperatures between 700 and 1000 °C to achieve high equilibrium conversion of CH4 and CO2 to the syngas (H2 and CO). The conventional catalysts used for DRM are Ni-based catalysts. However, many of these catalysts suffer from the short longevity due to carbon deposition. This study aims to evaluate the effect of La and Ca as promoters for Ni-based catalysts supported on two different zeolite supports, ZL (A) (BET surface area = 925 m2/g, SiO2/Al2O3 mol ratio = 5.1), and ZL (B) (BET surface area = 730 m2/g, SiO2/Al2O3 mol ratio = 12), for DRM. The physicochemical properties of the prepared catalysts were characterized with XRD, BET, TEM and TGA. These catalysts were tested for DRM in a microtubular reactor at reaction conditions of 700 °C. The catalyst activity results show that the catalysts Ni/ZL (B) and Ca-Ni/ZL (B) give the highest methane conversion (60 %) with less time on stream stability compared with promoted Ni on ZL (A). In contrast, La-containing catalysts, La-Ni/ZL (B), show more time on stream stability with minimum carbon content for the spent catalyst indicating the enhancement of the promoters to the Ni/ZL (A) and (B), but with less catalytic activity performance in terms of methane and carbon dioxide conversions due to rapid catalyst deactivation.

  5. Ni catalysts with different promoters supported on zeolite for dry reforming of methane

    KAUST Repository

    Alotaibi, Raja

    2015-07-08

    Dry reforming of methane (DRM) is considered a high endothermic reaction with operating temperatures between 700 and 1000 °C to achieve high equilibrium conversion of CH4 and CO2 to the syngas (H2 and CO). The conventional catalysts used for DRM are Ni-based catalysts. However, many of these catalysts suffer from the short longevity due to carbon deposition. This study aims to evaluate the effect of La and Ca as promoters for Ni-based catalysts supported on two different zeolite supports, ZL (A) (BET surface area = 925 m2/g, SiO2/Al2O3 mol ratio = 5.1), and ZL (B) (BET surface area = 730 m2/g, SiO2/Al2O3 mol ratio = 12), for DRM. The physicochemical properties of the prepared catalysts were characterized with XRD, BET, TEM and TGA. These catalysts were tested for DRM in a microtubular reactor at reaction conditions of 700 °C. The catalyst activity results show that the catalysts Ni/ZL (B) and Ca-Ni/ZL (B) give the highest methane conversion (60 %) with less time on stream stability compared with promoted Ni on ZL (A). In contrast, La-containing catalysts, La-Ni/ZL (B), show more time on stream stability with minimum carbon content for the spent catalyst indicating the enhancement of the promoters to the Ni/ZL (A) and (B), but with less catalytic activity performance in terms of methane and carbon dioxide conversions due to rapid catalyst deactivation.

  6. Exfoliation of two-dimensional zeolites in liquid polybutadienes

    KAUST Repository

    Sabnis, Sanket; Tanna, Vijesh A.; Li, Chao; Zhu, Jiaxin; Vattipalli, Vivek; Nonnenmann, Stephen S.; Sheng, Guan; Lai, Zhiping; Winter, H. Henning; Fan, Wei

    2017-01-01

    Layered zeolite precursors were successfully exfoliated by brief shearing or sonication with the assistance of commercially available telechelic liquid polybutadienes at room temperature. The exfoliated zeolite nanosheets can form a stable

  7. Morpho-chemical characterization and surface properties of carcinogenic zeolite fibers

    International Nuclear Information System (INIS)

    Mattioli, Michele; Giordani, Matteo; Dogan, Meral; Cangiotti, Michela; Avella, Giuseppe; Giorgi, Rodorico; Dogan, A. Umran; Ottaviani, Maria Francesca

    2016-01-01

    Highlights: • Differently carcinogenic zeolite fibers were investigated combining physico-chemical methods. • For the first time, zeolite fibers were studied by means of the EPR technique using different spin probes. • The structural properties and the adsorption capability are function of different types and distributions of adsorption sites. • The interacting ability of erionite is higher than that of other fibrous zeolites. • The surface interacting properties may be related with the carcinogenicity of the zeolite fibers. - Abstract: Erionite belonging to the zeolite family is a human health-hazard, since it was demonstrated to be carcinogenic. Conversely, offretite family zeolites were suspected carcinogenic. Mineralogical, morphological, chemical, and surface characterizations were performed on two erionites (GF1, MD8) and one offretite (BV12) fibrous samples and, for comparison, one scolecite (SC1) sample. The specific surface area analysis indicated a larger availability of surface sites for the adsorption onto GF1, while SC1 shows the lowest one and the presence of large pores in the poorly fibrous zeolite aggregates. Selected spin probes revealed a high adsorption capacity of GF1 compared to the other zeolites, but the polar/charged interacting sites were well distributed, intercalated by less polar sites (Si–O–Si). MD8 surface is less homogeneous and the polar/charged sites are more interacting and closer to each other compared to GF1. The interacting ability of BV12 surface is much lower than that found for GF1 and MD8 and the probes are trapped in small pores into the fibrous aggregates. In comparison with the other zeolites, the non-carcinogenic SC1 shows a poor interacting ability and a lower surface polarity. These results helped to clarify the chemical properties and the surface interacting ability of these zeolite fibers which may be related to their carcinogenicity.

  8. Catalytic behavior of metal-organic frameworks and zeolites: Rationalization and comparative analysis

    Czech Academy of Sciences Publication Activity Database

    Opanasenko, Maksym

    2015-01-01

    Roč. 243, APR 2015 (2015), s. 2-9 ISSN 0920-5861 R&D Projects: GA ČR GA14-07101S Institutional support: RVO:61388955 Keywords : Metal -organic frameworks * Zeolites * heterogeneous catalysis Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 4.312, year: 2015

  9. Three-dimensional 10-ring zeolites: The activities in toluene alkylation and disproportionation

    Czech Academy of Sciences Publication Activity Database

    Kubů, Martin; Žilková, Naděžda; Zones, S. I.; Chen, C.-Y.; Al-Khattaf, S.; Čejka, Jiří

    2016-01-01

    Roč. 259, JAN 2016 (2016), s. 97-106 ISSN 0920-5861 R&D Projects: GA ČR GBP106/12/G015 Institutional support: RVO:61388955 Keywords : 10-ring zeolites * TUN * IMF Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 4.636, year: 2016

  10. Retention of Cs on zeolite, bentonite and their mixtures

    International Nuclear Information System (INIS)

    Atun, G.

    2002-01-01

    The sorption behavior of cesium on zeolite and bentonite minerals and their mixtures was studied by means of a batch method and a tracer technique. All experiments were carried out in the presence of CsCl spiked with 137 Cs and NaCl as a supporting electrolyte in varying concentrations. The distribution coefficients (K D ) did not show significant differences at low Cs + loadings while they decreased in the high loading region. Freundlich and D-R isotherms were applied to the adsorption data of zeolite and bentonite. Adsorption capacities and mean energies calculated from D-R isotherm parameters decreased by increasing ionic strength on both minerals. The identification of the specific uptake sites was attempted on the basis of the Freundlich isotherm. Experimentally observed distribution coefficients of Cs on two mineral mixtures were smaller than theoretically calculated values, except at the highest NaCl concentration. (author)

  11. From Double-Four-Ring Germanosilicates to New Zeolites: In Silico Investigation

    Czech Academy of Sciences Publication Activity Database

    Trachta, Michal; Bludský, Ota; Čejka, Jiří; Morris, R. E.; Nachtigall, P.

    2014-01-01

    Roč. 15, č. 14 (2014), s. 2972-2976 ISSN 1439-4235 R&D Projects: GA ČR GBP106/12/G015 Institutional support: RVO:61388963 ; RVO:61388955 Keywords : density functional calculations * in silico studies * structure * synthesis * zeolites Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 3.419, year: 2014

  12. Kinetics and thermodynamic for sorption of arsenate by Lanthanum-exchanged zeolite

    International Nuclear Information System (INIS)

    Mohd Jelas Haron; Saiful Adli Masdan; Mohd Zobir Hussein; Zulkarnain Zainal; Anuar Kassim

    2007-01-01

    Zeolites are crystalline, hydrated aluminosilicate containing exchangeable alkaline and alkaline earth cations in their structural frameworks. Since zeolites have permanent negative charges on their surfaces, they have no affinity for anions. However recent studies have shown that modification of zeolites with certain surfactants or metal cations yield sorbents with a strong affinity for many anions. In this paper, modification of zeolites (zeolite A, X and ZSM5) were performed by exchange of naturally occurring cations with lanthanum ion that forms low solubility arsenate salt. The exchanged zeolites were used to sorb arsenate from aqueous solution. Among parameters investigated were effect of pH, arsenate initial concentrations, contact time and temperature. The maximum exchanged capacity of La (III) ion was obtained when using solution with initial pH of 4. Zeolite X gives the highest La (III) exchanged capacity compared to other zeolites. The results showed that As (V) sorption by La-zeolites occurred at about pH 6.5 and increased as pH increased and reaching maximum at equilibrium pH about 7.8. On the other hand, almost no arsenate sorption occurred on un exchanged zeolites. This indicates that La (III) ion on the exchanged zeolites is taking part on the As(V) sorption via surface precipitation. The results also showed that the sorption capacities increased with increasing initial As (V) concentrations. The sorption followed Langmuir model with maximum sorption capacities of 0.41, 0.21 and 0.19 mmol/g at 25 degree Celsius for La exchanged zeolite X (La-ZX), La exchanged zeolite ZSM5 (La-ZSM) and La exchanged zeolite A (La-ZA), respectively. The amounts of sorption of As (V) by La exchanged zeolite increased as temperature increased from 25 to 70 degree Celsius indicating that the process is endothermic. The free energy changes ( ΔG degree) for the sorption at 25 degree Celsius were -10.25, -9.65 and -8.49 kJ/ mol for La-ZX, La-ZSM and La-ZA, respectively. The

  13. Cure kinetics and mechanical interfacial characteristics of zeolite/DGEBA composites

    International Nuclear Information System (INIS)

    Park, Soo Jin; Kim, Young Mi; Shin, Jae Sup

    2003-01-01

    In this work, the zeolite/diglycidylether of bisphenol A(DGEBA) systems were investigated in terms of the cure kinetics and mechanical interfacial properties of the composites. The 4, 4-Diamino Diphenyl Methane(DDM) was used as a curing agent for epoxy. Two types of zeolite(PZ) were prepared with 15 and 35 wt% KOH treatments(15-BZ and 35-BZ, respectively) for 24 h, and their surface characteristics were studied by X-ray Photoelectron Spectroscopy (XPS) and X-Ray Diffraction (XRD). Cure kinetics of the composites were examined in the context of Differential Scanning Calorimetry(DSC), and mechanical interfacial properties were investigated in critical stress intensity factor(K IC ) and critical strain energy release rate(G IC ). In the results of XPS and XRD, sodium ion(Na) of zeolite was exchanged for potassium ion(K), resulting from the treatment of KOH. Also, Si 2p /A1 2p composition ratios of the treated zeolite were increased, which could be attributed to the weakening of A1-O bond in framework. Cure activation energy(E a ) of 15-BZ composites was decreased, whereas K IC and G IC were increased, compared with those of the pure zeolite/DGEBA composites. It was probably accounted that the acidity of zeolite was increased by surface treatments and the cure reaction between zeolite and epoxy was influenced on the increased acidity of zeolite

  14. Reduction volume of radioactive wastes using natural zeolite

    International Nuclear Information System (INIS)

    Endro Kismolo; Nurimaniwathy; Vemi Ridantami

    2013-01-01

    The aim of this experience was to know of the characteristics of zeolite as the sorbent for reduction volume of liquid waste with the Pb contaminant contain. The experiment was done by sorption method a batch performed by using zeolite from Gedangsari Gunung Kidul with the grain size (-60+80) mesh, (-80+100) mesh dan (-100+120) mesh which was activated by (NH 4 ) CI and NH 4 N0 3 1.0 M. Weight of sorbent was added was variated from 5.0 to 40.0 %, and variation of silica sand to added from 0.5 to 2.5 % of weight sorbent. Stirring speed was varied from 30 to 180 rpm and the stirring time of 10 to 120 minutes, and filtrates from filtering process to analyzed by Absorption Analysis Spectrophotometry utilities. From the experience can be achieved of data that the best sorption to obtained at the condition of zeolite on (-80+100) mesh, sorbent added of 25 %, stirring speed of 120 rpm, time of stirring of 90 minutes, and the setting time of 120 minutes. At this condition to obtained sorption efficiency are 64.162 % for natural zeolite, 7.034 % for zeolite be activated with NH 4 N0 3 and 77.414 % for zeolite be activated with NH 4 Cl 1.0 M. (author)

  15. Catalytic conversion of ethanol on H-Y zeolite

    Directory of Open Access Journals (Sweden)

    Čegar Nedeljko

    2005-01-01

    Full Text Available The catalytic activity of the H-form of synthetic zeolite NaY was examined in this study. The catalytic activity was determined according to the rate of ethanol conversion in a gas phase in the static system. In the conversion of ethanol on synthetic NaY zeolite at 585, 595, and 610 K, on which the reaction develops at an optimal rate, ethene and diethyl ether are evolved in approximately the same quantity. After transforming the NaY zeolite into the H-form, its catalytic activity was extremely increases so, the reaction develops at a significantly lower temperature with a very large increase in the reaction rate. The distribution of the products also changes, so that at lower temperatures diethyl ether is elvolved in most cases, and the development of ethene is favored at higher ones, and after a certain period of time there is almost complete conversion of ethanol into ethene. The increase in catalytic activity, as well as the change of selectivity of conversion of ethanol on the H-form of zeolite, is the result of removing Na+ cations in the NaY zeolite, so that more acidic catalyst is obtained which contains a number of acidic catalytically active centers, as well as a more powerful one compared to the original NaY zeolite.

  16. Inhibition of palm oil oxidation by zeolite nanocrystals.

    Science.gov (United States)

    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.

  17. Mixing of zeolite powders and molten salt

    International Nuclear Information System (INIS)

    Pereira, C.; Zyryanov, V.N.; Lewis, M.A.; Ackerman, J.P.

    1996-01-01

    Transuranics and fission products in a molten salt can be incorporated into zeolite A by an ion exchange process and by a batch mixing or blending process. The zeolite is then mixed with glass and consolidated into a monolithic waste form for geologic disposal. Both processes require mixing of zeolite powders with molten salt at elevated temperatures (>700 K). Complete occlusion of salt and a uniform distribution of chloride and fission products are desired for incorporation of the powders into the final waste form. The relative effectiveness of the blending process was studied over a series of temperature, time, and composition profiles. The major criteria for determining the effectiveness of the mixing operations were the level and uniformity of residual free salt in the mixtures. High operating temperatures (>775 K) improved salt occlusion. Reducing the chloride levels in the mixture to below 80% of the full salt capacity of the zeolite significantly reduced the free salt level in the final product

  18. Measuring the Bronsted acid strength of zeolites - does it correlate with the O-H frequency shift probed by a weak base?

    Czech Academy of Sciences Publication Activity Database

    Arean, C. O.; Delgado, M. R.; Nachtigall, P.; Thang, H. V.; Rubeš, M.; Bulánek, R.; Eliášová, Pavla

    2014-01-01

    Roč. 16, č. 21 (2014), s. 10129-10141 ISSN 1463-9076 R&D Projects: GA ČR GBP106/12/G015 Grant - others:GA MŠk(CZ) LM2010005 Institutional support: RVO:61388955 Keywords : zeolites * catalysis * H-MSM+22 zeolites Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 4.493, year: 2014

  19. Detergent zeolite complex "Alusil", Zvornik

    OpenAIRE

    Stanković Mirjana S.; Pezo Lato L.

    2003-01-01

    The IGPC Engineering Department designed the basis technological and machine projects for a detergent zeolite complex, on the basis of which a pilot plant with an initial capacity of 5,000 t/y was constructed in 1983 within Birač-Zvornik production complex. Additional projects were done afterwards and the starting capacity increased to 200,000 t/y in 1988. This plant became the biggest producer of detergent zeolite in the world. These projects were manufactured on the basis of specific techno...

  20. Preliminary study of zeolite-pva composite application in removal of SR-90

    International Nuclear Information System (INIS)

    Las, Thamzil; Zamroni, Huzen; Sugiarto; Darsono

    1998-01-01

    Zeolite-PAN composite was prepared by contacting the purified Bayah and Lampung zeolites with poly-vinyl alcohol binder and cured by using Gamma-ray of Co-60 at various doses, i.e., 10, 20, 30 dan 40 kGray with dose rates 7.5 kGy/hour. Zeolite-PAN composites were treated with solution containing Sr-90 up to 5 days and the Sr sorption was measured by Liquid Scintillation Counter for determination of their sorption efficiencies. The result obtained that, zeolite-PAN composites were shown high sorption efficiencies on the composites zeolite-PVA which was formulated from 20% zeolite, irradiated by 40 kGy and obtained the sorption efficiency of 94% with the Kd values similar to the purified zeolites. (author)

  1. Utilization of Zeolites in environmentally protection

    Energy Technology Data Exchange (ETDEWEB)

    Kallo, D. [Hungarian Academy of Sciences, Chemical Research Center, Institute of Chemistry, Budapest (Hungary)

    2000-07-01

    It has been attempted to present the most important fields of natural zeolite applications in environmental protection. Realized and approved utilizations were demonstrated inciting the reader to take these materials into consideration for solution of similar problems. The outlined properties can be used for other purposes not discussed in this review. They can be applied, e.g., in fish farming, transportation of living fishes when simultaneous ammonium and carbon dioxide removals is required: ammonium is exchanged for calcium present in the zeolite and CO{sub 2} is then precipitated in the form of CaCO{sub 3}; in treatment of diluted manure when undesired organics can be fixed and bactericide effects can be attained. Natural zeolites are used, therefore, as deodorant of litter of dogs or cats. Small amounts of metal cations, e.g., Cu{sup 2+}, Ag{sup +} or Zn{sup 2+}, introduced by ion exchange may disinfect contacting water. Due to water adsorption and desorption capability natural zeolite as construction materials exert some conditioning effect without any mechanical accessory. It seems likely the human ingenuity will continue to discover new applications in the future.

  2. Exploitation of Unique Properties of Zeolites in the Development of Gas Sensors

    Directory of Open Access Journals (Sweden)

    Prabir K. Dutta

    2012-04-01

    Full Text Available The unique properties of microporous zeolites, including ion-exchange properties, adsorption, molecular sieving, catalysis, conductivity have been exploited in improving the performance of gas sensors. Zeolites have been employed as physical and chemical filters to improve the sensitivity and selectivity of gas sensors. In addition, direct interaction of gas molecules with the extraframework cations in the nanoconfined space of zeolites has been explored as a basis for developing new impedance-type gas/vapor sensors. In this review, we summarize how these properties of zeolites have been used to develop new sensing paradigms. There is a considerable breadth of transduction processes that have been used for zeolite incorporated sensors, including frequency measurements, optical and the entire gamut of electrochemical measurements. It is clear from the published literature that zeolites provide a route to enhance sensor performance, and it is expected that commercial manifestation of some of the approaches discussed here will take place. The future of zeolite-based sensors will continue to exploit its unique properties and use of other microporous frameworks, including metal organic frameworks. Zeolite composites with electronic materials, including metals will lead to new paradigms in sensing. Use of nano-sized zeolite crystals and zeolite membranes will enhance sensor properties and make possible new routes of miniaturized sensors.

  3. Thermal Analysis of Lampung Zeolite as Ion Cesium Replacement

    International Nuclear Information System (INIS)

    Aslina-Br-Ginting; Dian-Anggraini; Arif-Nugroho

    2007-01-01

    Zeolite have the cation can move freely and as exchangeable partly or totally with other cations. Therefore, it can serve the purpose of ion exchanger very selectively to ion cesium which is present in fuel waste. In this research analysis of pore surface area, radius pore, and adsorption have been done. After the characters of Lampung zeolite is known and then analysis of cation exchange capacity (CEC) toward ion 137 Cs is conducted, analysis of Lampung zeolite adsorption to ion 137 Cs in waste of fissile product and in research waste is subsequently done. Result of analysis show Lampung zeolite has surface area of 10,0478 m 2 , specific surface area of 47,0841 m 2 /g, pore radius of 19,3020 o A and adsorption of 24,500 cc/g. For application as a ion exchange, Lampung zeolite can adsorb ion 137 Cs reaching maximum at concentration of CsCl 0,5 N with the contact time 1 day and the optimum KTK value is 0,8360 m eq/g. While Lampung zeolite is able to adsorb 86,4 % ion Cs in waste of fission product. (author)

  4. The Effect of Zeolite on Aggregate Stability Indices

    Directory of Open Access Journals (Sweden)

    F. Sohrab

    2016-02-01

    Full Text Available Introduction: Soil structural stability affects the profitability and sustainability of agricultural systems. Particle size distribution (PSD and aggregate stability are the important characteristics of soil. Aggregate stability has a significant impact on the development of the root system, water and carbon cycle and soil resistance against soil erosion. Soil aggregate stability, defined as the ability of the aggregates to remain intact when subject to a given stress, is an important soil property that affects the movement and storage of water, aeration, erosion, biological activity and growth of crops. Dry soil aggregate stability (Mean Weight Diameter (MWD, Geometric Mean Diameter (GMD and Wet Aggregate Stability (WAS are important indices for evaluating soil aggregate stability.To improve soil physical properties, including modifying aggregate, using various additives (organic, inorganic and chemicals, zeolites are among what has been studied.According to traditional definition, zeolites are hydratealuminosilicates of alkaline and alkaline-earth minerals. Their structure is made up of a framework of[SiO4]−4 and [AlO4]−5 tetrahedron linked to each other's cornersby sharing oxygen atoms. The substitution of Si+4 by Al+3 intetrahedral sites results inmore negative charges and a high cation exchange capacity.Zeolites, as natural cation exchangers, are suitable substitutes to remove toxic cations. Among the natural zeolites,Clinoptilolite seems to be the most efficient ion exchanger and ion-selective material forremoving and stabilizing heavy metals.Due to theexisting insufficient technical information on the effects of using different levels of zeolite on physical properties of different types of soils in Iran, the aim of this research was to assess the effects of two different types of zeolite (Clinoptilolite natural zeolite, Z4, and Synthetic zeolite, A4 on aggregate stability indicesof soil. Materials and Methods: In this study at first

  5. Dealuminization treatment effect of krypton gas adsorption on zeolite

    International Nuclear Information System (INIS)

    Shin, J. M.; Shin, S. W.; Park, J. J.; Lee, H. H.; Yang, M. S.

    2003-01-01

    During the OREOX process of DUPIC fuel fabrication, krypton is released as a noble fission gas. In order to treat Kr safely, adsorption method on solids havs been selected. In order to determine the optimum extraction conditions of zeolite for Kr adsorption, the preliminary experiments for the concentration of hydrochloric acid were conducted. It was found that zeolite treated with 2N hydrochloric acid solution is superior to the zeolite untreated with HCl solution. When the zeolite was treated with 2N hydrochloric acid, it was found that the surface area was decreased. The micropores and the pore volume were increased and the adsorption amount of Kr gas was increased

  6. Regeneration of zeolite catalysts of isobutane alkylation with butenes

    Energy Technology Data Exchange (ETDEWEB)

    Manza, I.A.; Tsupryk, I.N.; Bartyshevskii, V.A.; Gaponenko, O.I.; Petrilyak, K.I.

    1986-12-10

    The industrial adoption of alkylation of isoalkanes with alkenes is held back by the rapid and irreversible deactivation of the zeolite catalysts appropriate to the process. This paper is aimed specifically at the restoration of the catalytic activity and increase in the service life of zeolite alkylation catalysts. The catalyst chosen for the investigation was HLaCaNaX zeolite both unmodified and modified with various multivalence cations. The thermochemical and oxidative regeneration process as well as the equipment utilized are described. Both the advantages and the drawbacks of the method are given; explanations for the possibly irreversible losses of the catalytic properties in the regenerated zeolites are also put forward.

  7. Desulfurization of the exhaust gas with zeolite synthesized from diatomaceous earth

    Energy Technology Data Exchange (ETDEWEB)

    Miyamoto, M

    1975-07-01

    Both A type and X type zeolites were prepared from diatomaceous earth and tested for use in flue gas desulfurization. Several diatomaceous earths of known chemical compositions were mixed to obtain a desired molar ratio of silicates, whose maturation was achieved in two steps; room temperature maturation and reflux maturation by heating. If the second maturation was carried out for more than 12 hr, the X type zeolite formation was low. At the best conditions, 80% pure zeolite could be prepared for both types according to their x-ray diffraction spectra. The synthesized x type zeolite adsorbed sulfur dioxide more efficiently than A type zeolite. When a simulated flue gas containing 680 to 840 ppM sulfur dioxide was passed at a flow rate of 9.0 Nl/min through a 250 g zeolite column, the column breaking time (time required for the SO/sub 2/ concentration of the column effluent to reach 10% of the initial SO/sub 2/ concentration) was 5.3 hr, while that for the commercial zeolite and activated carbon was 6.8 hr and 8.0 hr, respectively. If the flue gas contained more than 1% moisture, the adsorbed water reacted with SO/sub 2/ and the zeolite crystal tended to break down. The use of zeolite for flue gas desulfurization was more costly than the use of activated carbon.

  8. The Effect of Zeolite Composition and Grain Size on Gas Sensing Properties of SnO2/Zeolite Sensor

    Directory of Open Access Journals (Sweden)

    Yanhui Sun

    2018-01-01

    Full Text Available In order to improve the sensing properties of tin dioxide gas sensor, four kinds of different SiO2/Al2O3 ratio, different particle size of MFI type zeolites (ZSM-5 were coated on the SnO2 to prepared zeolite modified gas sensors, and the gas sensing properties were tested. The measurement results showed that the response values of ZSM-5 zeolite (SiO2/Al2O3 = 70, grain size 300 nm coated SnO2 gas sensors to formaldehyde vapor were increased, and the response to acetone decreased compared with that of SnO2 gas sensor, indicating an improved selectivity property. The other three ZSM-5 zeolites with SiO2/Al2O3 70, 150 and 470, respectively, and grain sizes all around 1 μm coated SnO2 sensors did not show much difference with SnO2 sensor for the response properties to both formaldehyde and acetone. The sensing mechanism of ZSM-5 modified sensors was briefly analyzed.

  9. Determination of the surface area and sizes of supported copper nanoparticles through organothiol adsorption—ñhemisorption

    Energy Technology Data Exchange (ETDEWEB)

    Ndolomingo, Matumuene Joe; Meijboom, Reinout, E-mail: rmeijboom@uj.ac.za

    2016-12-30

    Highlights: • Cu on γ-Al{sub 2}O{sub 3} catalysts were prepared and characterized. • The ligand sorption-based technique was used for the determination of specific surface area and particle sizes. • The ligand packing density on Cu nanoparticles was quantified. • A fair agreement was found between the Cu particle sizes obtained from ligand adsorption and TEM methods. • The oxidation of morin by hydrogen peroxide was used to evaluate the catalytic activities of the Cu supported catalysts. - Abstract: The mechanisms involving the nanoparticle surfaces in catalytic reactions are more difficult to elucidate due to the nanoparticle surface unevenness, size distributions, and morphological irregularity. True surface area and particle sizes determination are key aspects of the activity of metal nanoparticle catalysts. Here we report on the organothiol adsorption-based technique for the determination of specific surface area of Cu nanoparticles, and their resultant sizes on γ-Al{sub 2}O{sub 3} supports. Quantification of ligand packing density on copper nanoparticles is also reported. The concentration of the probe ligand, 2-mercaptobenzimidazole (2-MBI) before and after immersion of supported copper catalysts was determined by ultraviolet-visible spectrometry (UV–vis). The amount of ligand adsorbed was found to be proportional to the copper nanoparticles surface area. Atomic absorption spectrometry (AAS), N{sub 2}-physisorption (BET), transmission electron microscopy (TEM), scanning electron microscopy (SEM) and thermogravimetric analysis (TGA) were used for the characterization of the catalysts. A fair agreement was found between particle sizes obtained from ligand adsorption and TEM methods. The catalytic activity of the copper nanoparticles related to their inherent surface area was evaluated using the model reaction of the oxidation of morin by hydrogen peroxide.

  10. Fluorescence labelling as tool for zeolite particle tracking in nanoremediation approaches

    International Nuclear Information System (INIS)

    Gillies, Glenn; Mackenzie, Katrin; Kopinke, Frank-Dieter; Georgi, Anett

    2016-01-01

    Colloidal Fe-zeolites such as Fe-BEA-35 are currently under study as new adsorbent and catalyst materials for in-situ chemical oxidation with H_2O_2. As for nanoremediation in general, the availability of suitable particle detection methods is a requirement for successful process development and particle tracing. Detection and distinguishing between natural colloids and introduced particles with a similar composition are a challenge. By means of fluorescence labelling, a highly specific detection option for Fe-BEA-35 was developed. ‘Ship-in-a-bottle’ synthesis of fluorescein within the zeolite pores, which was applied for the first time for a BEA type zeolite, provides a product with stable and non-extractable fluorescence. When the fluorescent labelled zeolite is added at a concentration of 1 wt.% referring to the total zeolite mass, a very low detection limit of 1 mg/L of total zeolite is obtained. Compared to commonly applied turbidity measurements, detection via fluorescence labelling is much more specific and sensitive. Fluorescence is only marginally affected by carboxymethyl cellulose, which is frequently applied as stabilizer in application suspensions but will be depleted upon contact with H_2O_2. Transport properties of fluorescent labelled and non-labelled Fe-zeolite particles are in agreement as determined in a column study with quartz sand and synthetic groundwater (classified as very hard). - Highlights: • Fluorescent BEA zeolite was prepared for first time by ‘ship-in-a-bottle’ synthesis. • Fluorescein synthesized inside zeolite channels is stable and non-extractable. • Detection limit of Fe-zeolite particles in suspension with 1 wt.% fluorescent zeolite is 1 mg/L. • Transport properties of fluorescent and Fe-loaded BEA particles are identical.

  11. The potential of Saudi Arabian natural zeolites in energy recovery technologies

    International Nuclear Information System (INIS)

    Nizami, A.S.; Ouda, O.K.M.; Rehan, M.; El-Maghraby, A.M.O.; Gardy, J.; Hassanpour, A.; Kumar, S.; Ismail, I.M.I.

    2016-01-01

    Energy consumption in KSA (kingdom of Saudi Arabia) is growing rapidly due to economic development with raised levels of population, urbanization and living standards. Fossil fuels are currently solely used to meet the energy requirements. The KSA government have planned to double its energy generating capacity (upto 120 GW (gigawatts)) by 2032. About half of the electricity capacity of this targeted energy will come from renewable resources such as nuclear, wind, solar, WTE (waste-to-energy) etc. Natural zeolites are found abundantly in KSA at Jabal Shamah occurrence near Jeddah city, whose characteristics have never been investigated in energy related applications. This research aims to study the physical and chemical characteristics of natural zeolite in KSA and to review its potential utilization in selected WTE technologies and solar energy. The standard zeolite group of alumina–silicate minerals were found with the presence of other elements such as Na, Mg and K etc. A highly crystalline structure and thermal stability of natural zeolites together with unique ion exchange, adsorption properties, high surface area and porosity make them suitable in energy applications such as WTE and solar energy as an additive or catalyst. A simple solid–gas absorption system for storing solar energy in natural zeolites will be a cheap alternative method for KSA. In AD (anaerobic digestion), the dual characteristics of natural zeolite like Mordenite will increase the CH_4 production of OFMSW (organic fraction of municipal solid waste). Further investigations are recommended to study the technical, economical, and environmental feasibility of natural zeolite utilization in WTE technologies in KSA. - Highlights: • A highly crystalline structure is found in natural zeolites. • Natural zeolites will store solar energy in solid–gas absorption system. • The composites of natural zeolites will produce more liquid fuel like gasoline. • The natural zeolite will increase

  12. Theoretical investigation of CO interaction with copper sites in zeolites: Periodic DFT and hybrid quantum mechanical/interatomic potential function study

    Czech Academy of Sciences Publication Activity Database

    Bludský, Ota; Šilhan, Martin; Nachtigall, Petr; Bucko, T.; Benco, L.; Hafner, J.

    2005-01-01

    Roč. 109, - (2005), s. 9631-9638 ISSN 1089-5647 R&D Projects: GA MŠk(CZ) LC512 Grant - others:Austrian Science Funds(AT) Pl 7020 Institutional research plan: CEZ:AV0Z4055905 Keywords : Cu-exchanged zeolites * carbon-monoxide Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 3.679, year: 2003

  13. Utilization of Natural Zeolite from Ponorogo and Purworejo for Naphthol Substance Adsorption

    Science.gov (United States)

    Imandiani, Sundus; Indira, Christine; Johan, Anthony; Budiyono

    2018-02-01

    Indonesia has many zeolite producing areas yet untapped. Researchers developed the utilization of natural zeolites useful for the adsorption of naphthol dyes commonly found in batik waste. In this study researchers used natural zeolites from Purworejo and Ponorogo that are activated using hydrochloric acid that is used for adsorption. The purpose of this research is to know the effect of natural zeolite activation from Ponorogo and Purworejo on the effectiveness of adsorption of naphthol dyes widely used in batik industry. Natural zeolite was activated using HCl concentration of 1.3N; 1.8N; 3.2N; and 3.9N for 60 minutes. The methods are preparation of natural zeolite from Purworejo and Ponorogo, dealumination using hydrochloric acid, adsorption process of naphthol dyes using activated zeolite, and test of adsorption result with uv-vis spectrophotometry. The test results showed that the higher HCl concentration will increase adsorption capacity. This can be known from the concentration of naphthol dye which decreased both using natural zeolite Ponorogo and Purworejo. While the effectiveness of adsorption shows natural zeolite Purworejo has a greater adsorption capacity than Ponorogo with optimum conditions of dealumination using concentration HCl 3,9N.

  14. Generalized synthesis of mesoporous shells on zeolite crystals

    KAUST Repository

    Han, Yu; Pitukmanorom, Pemakorn; Zhao, L. J.; Ying, Jackie

    2010-01-01

    A simple and generalized synthetic approach is developed for creating mesoporous shells on zeolite crystals. This method allows for the tailoring of thickness, pore size, and composition of the mesoporous shell, and can be applied to zeolites

  15. Investigating the Influence of Temperature on the Kaolinite-Base Synthesis of Zeolite and Urease Immobilization for the Potential Fabrication of Electrochemical Urea Biosensors.

    Science.gov (United States)

    Anderson, David Ebo; Balapangu, Srinivasan; Fleischer, Heidimarie N A; Viade, Ruth A; Krampa, Francis D; Kanyong, Prosper; Awandare, Gordon A; Tiburu, Elvis K

    2017-08-08

    Temperature-dependent zeolite synthesis has revealed a unique surface morphology, surface area and pore size which influence the immobilization of urease on gold electrode supports for biosensor fabrication. XRD characterization has identified zeolite X (Na) at all crystallization temperatures tested. However, N₂ adsorption and desorption results showed a pore size and pore volume of zeolite X (Na) 60 °C, zeolite X (Na) 70 °C and zeolite X (Na) 90 °C to range from 1.92 nm to 2.45 nm and 0.012 cm³/g to 0.061 cm³/g, respectively, with no significant differences. The specific surface area of zeolite X (Na) at 60, 70 and 90 °C was 64 m²/g, 67 m²/g and 113 m²/g, respectively. The pore size, specific surface area and pore volumes of zeolite X (Na) 80 °C and zeolite X (Na) 100 °C were dramatically increased to 4.21 nm, 295 m²/g, 0.762 cm³/g and 4.92 nm, 389 m²/g, 0.837 cm³/g, in that order. The analytical performance of adsorbed urease on zeolite X (Na) surface was also investigated using cyclic voltammetry measurements, and the results showed distinct cathodic and anodic peaks by zeolite X (Na) 80 °C and zeolite X (Na) 100 °C. These zeolites' molar conductance was measured as a function of urea concentration and gave an average polynomial regression fit of 0.948. The findings in this study suggest that certain physicochemical properties, such as crystallization temperature and pH, are critical parameters for improving the morphological properties of zeolites synthesized from natural sources for various biomedical applications.

  16. High-resolution adsorption analysis of pillared zeolites IPC-3PI and MCM-36

    Czech Academy of Sciences Publication Activity Database

    Zukal, Arnošt; Kubů, Martin

    2014-01-01

    Roč. 43, č. 27 (2014), s. 10558-10565 ISSN 1477-9226 R&D Projects: GA ČR GP13-17593P Institutional support: RVO:61388955 Keywords : zeolites * adsorption * microporosity Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 4.197, year: 2014

  17. Synthesis of Zeolite Materials for Noble Gas Separation

    International Nuclear Information System (INIS)

    Achey, R.; Rivera, O.; Wellons, M.; Hunter, D.

    2017-01-01

    Microporous zeolite adsorbent materials are widely used as a medium for separating gases. Adsorbent gas separation systems can run at ambient temperature and require minimal pressure to flow the input gas stream across the adsorbent bed. This allows for low energy consumption relative to other types of separation systems. Specific zeolites also have a high capacity and selectivity for the gases of interest, leading to compact and efficient separation systems. These characteristics are particularly advantageous for the application of signatures detection for non-proliferation, which often requires portable systems with low power draw. Savannah River National Laboratory currently is the leader in using zeolites for noble gas sampling for non-proliferation detection platforms. However, there is a constant customer need for improved sampling capabilities. Development of improved zeolite materials will lead to improved sampling technology. Microwave-assisted and conventional hydrothermal synthesis have been used to make a variety of zeolites tailored for noble gas separation. Materials characterization data collected in this project has been used to help guide the synthesis of improved zeolite materials. Candidate materials have been down-selected based on highest available surface area, maximum overall capacity for gas adsorption and highest selectivity. The creation of improved adsorbent materials initiated in this project will lead to development of more compact, efficient and effective noble gas collectors and concentrators. The work performed in this project will be used as a foundation for funding proposals for further material development as well as possible industrial applications.

  18. Synthesis of Zeolite Materials for Noble Gas Separation

    Energy Technology Data Exchange (ETDEWEB)

    Achey, R. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Rivera, O. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Wellons, M. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Hunter, D. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL)

    2017-10-02

    Microporous zeolite adsorbent materials are widely used as a medium for separating gases. Adsorbent gas separation systems can run at ambient temperature and require minimal pressure to flow the input gas stream across the adsorbent bed. This allows for low energy consumption relative to other types of separation systems. Specific zeolites also have a high capacity and selectivity for the gases of interest, leading to compact and efficient separation systems. These characteristics are particularly advantageous for the application of signatures detection for non-proliferation, which often requires portable systems with low power draw. Savannah River National Laboratory currently is the leader in using zeolites for noble gas sampling for non-proliferation detection platforms. However, there is a constant customer need for improved sampling capabilities. Development of improved zeolite materials will lead to improved sampling technology. Microwave-assisted and conventional hydrothermal synthesis have been used to make a variety of zeolites tailored for noble gas separation. Materials characterization data collected in this project has been used to help guide the synthesis of improved zeolite materials. Candidate materials have been down-selected based on highest available surface area, maximum overall capacity for gas adsorption and highest selectivity. The creation of improved adsorbent materials initiated in this project will lead to development of more compact, efficient and effective noble gas collectors and concentrators. The work performed in this project will be used as a foundation for funding proposals for further material development as well as possible industrial applications.

  19. ADSORPTION MALACHITE GREEN ON NATURAL ZEOLITE

    OpenAIRE

    Eko Ariyanto

    2012-01-01

    A natural zeolite was employed as adsorbent for reducing of malachite green from aqueous solution. A batch system was applied to study the adsorption of malachite green in single system on natural zeolite. The adsorption studies indicate that malachite green in single component system follows the second-order kinetics and the adsorption is diffusion process with two stages for malachite green. Malachite green adsorption isotherm follows the Langmuir model.

  20. PREPARATION, CHARACTERIZATIONS AND MODIFICATION OF Ni-Pd/NATURAL ZEOLITE CATALYSTS

    Directory of Open Access Journals (Sweden)

    Wega Trisunaryanti

    2010-06-01

    Full Text Available Preparation, and modification of Ni-Pd/natural zeolite as well as their characterizations had been carried out. The aim of this research for the fututure is to prepare the best characters catalyst for the conversion of waste plastics fraction to gasoline fraction (C5-C12 hydrocarbons. The preparation of catalysts was performed by reacting a natural zeolite with the precursor of Ni(NO32. 9H2O and PdCl2 in an ammonia solution (25%. The modifications were performed by varying the rasio of Ni/Pd loaded to the zeolite, whereas the Pd was previously loaded and total metal content was 1 wt.% based on the zeolite. The characterization of catalysts included determination of acidity gravimetrically by adsorption of ammonia or pyridine vapour  base method, metal content by Atomic Adsorption Spectrophotometer (AAS and X-ray Fluoresence (XRF and crystallinity by X-ray Diffraction (XRD. The treatment of catalysts using Etilene Diamine Tetra Acetic acid  (EDTA was performed to study the metal distribution on the outer or inner surface of the zeolite. The characterization results showed that the loading of metals to the zeolite increased its acidity and decreased its spesific surface area, however, did not defect its crystallnity.  The metals loaded on the zeolite were distributed inside the pore and at outer surface of the zeolite. For all catalyst samples, the acidities determined using ammonia were higher than those of pyridine, and the acidities determined before the EDTA treatment was lower than those after the treatment.  Metal contents of the zeolite before the EDTA treatment were higher than those after the treatment. The EDTA treatment enhanced the crystallinity of the sampel. The relationship between the metal rasio towards the acidity of the catalyst samples were in variation. Catalyst samples produced in this research have good characters, thus promisingly can be used for conversion process of waste plastics to gasoline fraction.    Keywords

  1. Zeolite Vitrification Demonstration Program nonradioactive-process operations summary

    International Nuclear Information System (INIS)

    Bryan, G.H.; Knox, C.A.; Goles, R.G.; Ethridge, L.J.; Siemens, D.H.

    1982-09-01

    The Submerged Demineralizer System is a process developed to decontaminate high-activity level water at Three Mile Island by sorbing the activity (primarily Cs and Sr) onto beds of zeolite. Pacific Northwest Laboratory's Zeolite Vitrification Demonstration Program has the responsibility of demonstrating the full-scale vitrification of this zeolite material. The first phase of this program has been to develop a glass formulation and demonstrate the vitrification process with the use of nonradioactive materials. During this phase, four full-scale nonradioactive demonstration runs were completed. The same zeolite mixture being used in the SDS system was loaded with nonradioactive isotopes of Cs and Sr, dried, blended with glass-forming chemicals and fed to a canister in an in-can melter furnace. During each run, the gaseous effluents were sampled. After each run, glass samples were removed and analyzed

  2. Zeolite-catalyzed biomass conversion to fuels and chemicals

    DEFF Research Database (Denmark)

    Taarning, Esben; Osmundsen, Christian Mårup; Yang, Xiaobo

    2011-01-01

    Heterogeneous catalysts have been a central element in the efficient conversion of fossil resources to fuels and chemicals, but their role in biomass utilization is more ambiguous. Zeolites constitute a promising class of heterogeneous catalysts and developments in recent years have demonstrated...... their potential to find broad use in the conversion of biomass. In this perspective we review and discuss the developments that have taken place in the field of biomass conversion using zeolites. Emphasis is put on the conversion of lignocellulosic material to fuels using conventional zeolites as well...

  3. Oxidation of Bioethanol using Zeolite-Encapsulated Gold Nanoparticles

    DEFF Research Database (Denmark)

    Mielby, Jerrik Jørgen; Abildstrøm, Jacob Oskar; Wang, Feng

    2014-01-01

    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...... zeolite crystals comprise a broad range of mesopores and contain up to several hundred gold nanoparticles with a diameter of 2-3nm 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...

  4. Oxidation of Bioethanol using Zeolite-Encapsulated Gold Nanoparticles

    DEFF Research Database (Denmark)

    Mielby, Jerrik Jørgen; Abildstrøm, Jacob Oskar; Wang, Feng

    2014-01-01

    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...... 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...

  5. FUNDAMENTALS AND APPLICATIONS OF PERVAPORATION THROUGH ZEOLITE MEMBRANES

    Science.gov (United States)

    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 ...

  6. Aided Phytostabilization of Copper Contaminated Soils with L. Perenne and Mineral Sorbents as Soil Amendments

    Science.gov (United States)

    Radziemska, Maja

    2017-09-01

    The present study was designed to assess phytostabilization strategies for the treatment of soil co-contaminated by increasing levels of copper with the application mineral amendments (chalcedonite, zeolite, dolomite). From the results it will be possible to further elucidate the benefits or potential risks derived from the application of different types of mineral amendments in the remediation of a copper contaminated soil. A glasshouse pot experiment was designed to evaluate the potential use of different amendments as immobilizing agents in the aided phytostabilization of Cu-contaminated soil using ryegrass (Lolium perenne L.). The content of trace elements in plants and total in soil, were determined using the method of spectrophotometry. All of the investigated element contents in the tested parts of L. perenne were significantly different in the case of applying mineral amendments to the soil, as well as increasing concentrations of copper. The greatest average above-ground biomass was observed for soil amended with chalcedonite. In this experiment, all analyzed metals accumulated predominantly in the roots of the tested plant. In general, applying mineral amendments to soil contributed to decreased levels of copper concentrations.

  7. Influence of zeolite and cement additions on mechanical behavior of sandy soil

    Directory of Open Access Journals (Sweden)

    Hossein Mola-Abasi

    2016-10-01

    Full Text Available It is well known that the cemented sand is one of economic and environmental topics in soil stabilization. In this instance, a blend of sand, cement and other materials such as fiber, glass, nanoparticle and zeolite can be commercially available and effectively used in soil stabilization in road construction. However, the influence and effectiveness of zeolite on the properties of cemented sand systems have not been completely explored. In this study, based on an experimental program, the effects of zeolite on the characteristics of cemented sands are investigated. Stabilizing agent includes Portland cement of type II and zeolite. Results show the improvements of unconfined compressive strength (UCS and failure properties of cemented sand when the cement is replaced by zeolite at an optimum proportion of 30% after 28 days. The rate of strength improvement is approximately between 20% and 78%. The efficiency of using zeolite increases with the increases in cement amount and porosity. Finally, a power function of void-cement ratio and zeolite content is demonstrated to be an appropriate method to assess UCS of zeolite-cemented mixtures.

  8. Preparation and performance of manganese-oxide-coated zeolite for the removal of manganese-contamination in groundwater.

    Science.gov (United States)

    Lyu, Cong; Yang, Xuejiao; Zhang, Shengyu; Zhang, Qihui; Su, Xiaosi

    2017-12-29

    A promising and easily prepared catalytic filler media, manganese-oxide-coated zeolite (MOCZ), for the removal of Mn (II) contamination in groundwater was studied. The optimal condition for MOCZ preparation was given as follows: acid activation of zeolite with 5% HCl mass percent for 12 h, then soaking of acid-activated zeolite with 7% KMnO 4 mass percent for 8 h, and finally calcination at 300°C for 5 h. Acid activation significantly enlarged the specific surface area of the zeolite (>79 m 2  g -1 ), subsequently enhancing the coating of manganese oxides onto the surface of the zeolite. This was further supported by the manganese-to-zeolite ratio (γ Mn ) and Energy dispersive analysis-mapping. The γ Mn was over 12.26 mg Mn g -1 zeolite, representing more active sites for the adsorption and catalytic-oxidation of Mn (II). As such, great performance of Mn (II) removal by MOCZ was obtained in the filter experiment. An estimated 98-100% removal efficiency of Mn (II) was achieved in a greatly short startup time (only 2 h). During the filtration process, newborn flocculent manganese oxides with a mixed-valence of manganese (Mn (II) and Mn (IV)) were generated on the MOCZ surface, further facilitating the adsorption and catalytic-oxidation of Mn (II). The filter with MOCZ as adsorbent had a great performance on the Mn (II) removal in a wide range of hydraulic retention time (HRT) (4-40 min), particularly in a short HRT. Besides, the filter prolonged the filtration period (60 days), which would significantly reduce the frequency of backwash. Thus, it could be concluded that MOCZ prepared in this study showed a good performance in terms of Mn (II) removal in waterworks, especially small waterworks in the villages/towns.

  9. Microwave preparation of Li-zeolite directly from alumatrane and silatrane

    International Nuclear Information System (INIS)

    Sathupunya, Mathavee; Gulari, Erdogan; Wongkasemjit, Sujitra

    2004-01-01

    Li-zeolites were successfully synthesized in a one-step sol-gel process and microwave technique using silatrane and alumatrane as precursors and lithium hydroxide as the hydrolytic agent. Many types of Li-zeolites were obtained by controlling synthesis parameters. Perfect crystalline zeolite, EDI type zeolite, was obtained at 90 deg. C after heating for 60 min while ABW type zeolite was produced after heating for 300 min at 110 deg. C. With increasing temperature, a higher packing density product was generated. Changing Si/Al loading ratio highly influenced the morphology of the synthesized product. With increasing Al loading, more irregular morphology products were obtained. Changing Li 2 O/SiO 2 ratio, led to changes in the unit cell structure and crystal morphology. Lowering the Li 2 O/SiO 2 ratio to one produced FAU type zeolite at 110 deg. C for 240 min. The thermal stability of EDI and ABW were very low while that of FAU was higher which might come from the effect of low ring strain construction of FAU

  10. β-Zeolite modified by ethylenediamine for sorption of Th(IV)

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Peng; Wu, Hanyu; Yuan, Ni; Yin, Zhuoxin; Pan, Duoqiang; Wu, Wangsuo [Lanzhou Univ. (China). Radiochemistry Lab.; Ministry of Education, Lanzhou (China). Key Lab. of Special Function Materials and Structure Design

    2017-08-01

    β-Zeolite-EDA was modified with ethylenediamine (EDA) after synthesized. The synthesized material was characterized and used for removal of Th(IV) from aqueous solutions. The influences of pH, ionic strength, contact time, temperature and humic acid (HA) on Th(IV) sorption onto synthesized β-zeolite-EDA was studied by batch technique. The dynamic process showed that the sorption of Th(IV) onto β-zeolite-EDA matched the pseudo-second-order kinetics model. The sorption of Th(IV) on β-zeolite-EDA was significantly dependent on pH values, the sorption percentage increased markedly at pH 3.5-4.5, and then maintained a steady state as pH values increased. Through simulating the sorption isotherms by Langmuir, Freundlich and Dubini-Radushkevich (D-R) models, it could be seen respectively that the sorption pattern of Th(IV) on β-zeolite-EDA was mainly controlled by surface complexation, and that the sorption processes was endothermic and spontaneous. The presence of HA increased Th(IV) sorption on β-zeolite-EDA.

  11. Selective synthesis of FAU-type zeolites

    Science.gov (United States)

    Garcia, Gustavo; Cabrera, Saúl; Hedlund, Jonas; Mouzon, Johanne

    2018-05-01

    In the present work, parameters influencing the selectivity of the synthesis of FAU-zeolites from diatomite were studied. The final products after varying synthesis time were characterized by scanning electron microscopy, energy dispersive spectroscopy, X-ray diffraction and gas adsorption. It was found that high concentrations of NaCl could completely inhibit the formation of zeolite P, which otherwise usually forms as soon as maximum FAU crystallinity is reached. In the presence of NaCl, the FAU crystals were stable for extended time after completed crystallization of FAU before formation of sodalite. It was also found that addition of NaCl barely changed the crystallization kinetics of FAU zeolite and only reduced the final FAU particle size and SiO2/Al2O3 ratio slightly. Other salts containing either Na or Cl were also investigated. Our results suggest that there is a synergistic effect between Na+ and Cl-. This is attributed to the formation of (Na4Cl)3+ clusters that stabilize the sodalite cages. This new finding may be used to increase the selectivity of syntheses leading to FAU-zeolites and avoid the formation of undesirable by-products, especially if impure natural sources of aluminosilica are used.

  12. Adsorption methods for hydrogen isotope storage on zeolite sieves

    International Nuclear Information System (INIS)

    Cristescu, Ioana; Cristescu, Ion; Vasut, Felicia; Brad, Sebastian; Lazar, Alin

    2001-01-01

    Adsorption molecular sieves and activated carbon were used for hydrogen isotopes. The adsorption process proceeds at liquid nitrogen and liquid hydrogen temperatures. The synthetic zeolites have similar properties as natural zeolites, but they have a regular pore structure and affinity for molecules of different size with defined shapes. Experimental results obtained at liquid nitrogen and liquid hydrogen temperatures evidenced the efficient behavior of the activated carbon and zeolite sieves for hydrogen isotope temporary storage. (authors)

  13. Cupric natural zeolites as microbic ides

    International Nuclear Information System (INIS)

    Contreras A, D.; Olguin G, M. T.; Alcantara D, D.; Burrola A, C.

    2009-01-01

    The Escherichia coli and the Candida albicans are considered contamination indicators for what these organisms reflect the water quality. The natural zeolites by their characteristics and properties, they could incorporate to a waters treatment system, as ion exchange, adsorbents and/or microbiocid agents, representing an alternative method of low cost. Inside this investigation work was found that depending on the microorganism type, it varies the quantity of cupric zeolite that is required to carry out the water disinfection, being great for the case of yeasts than the bacteria s. In addition to that marked differences are presented in the required time to reach this process. The characterization of the natural zeolite material, sodium and cupric, was realized by means of scanning electron microscopy, determining the elementary composition (Energy Dispersive Spectroscopy) of each one of them, and by X-ray diffraction. (Author)

  14. Synthesis and catalytic properties of titanium containing extra-large pore zeolite CIT-5

    Czech Academy of Sciences Publication Activity Database

    Přech, Jan; Kubů, Martin; Čejka, Jiří

    2014-01-01

    Roč. 227, MAY 2014 (2014), s. 80-86 ISSN 0920-5861 R&D Projects: GA ČR GBP106/12/G015 Institutional support: RVO:61388955 Keywords : zeolite CIT-5 * titanosilicate * epoxidation Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 3.893, year: 2014

  15. ADSORPTION MALACHITE GREEN ON NATURAL ZEOLITE

    Directory of Open Access Journals (Sweden)

    Eko Ariyanto

    2012-02-01

    Full Text Available A natural zeolite was employed as adsorbent for reducing of malachite green from aqueous solution. A batch system was applied to study the adsorption of malachite green in single system on natural zeolite. The adsorption studies indicate that malachite green in single component system follows the second-order kinetics and the adsorption is diffusion process with two stages for malachite green. Malachite green adsorption isotherm follows the Langmuir model.

  16. Detergent zeolite complex "Ceosil", Tallinn, Estonia

    OpenAIRE

    Stanković Mirjana S.; Pezo Lato L.

    2003-01-01

    The IGPC Engineering Department, together with the "Birac", Zvornik Engineering Department designed basic projects for detergent zeolite production, using waste flotation sand and hydrates. Several projects were completed: technological, machine, electrical, automation. On the basis of these projects, production plant in Tallinn, Estonia was constructed, with a capacity of 100,000 t/y from 1989. to 1993. This plant became the biggest producer of detergent zeolite in the world.Several goals we...

  17. PHOTODEGRADATION OF ALIZARIN S DYE USING TiO2-ZEOLITE AND UV RADIATION

    Directory of Open Access Journals (Sweden)

    Karna Wijaya

    2010-06-01

    Full Text Available An investigation of Alizarin S photodegradation using TiO2-zeolite and UV radiation was performed. TiO2-zeolite was prepared by dispersing oligocations of titanium into suspension of zeolite. The suspension was stirred and then filtered to separate the solid phase from the filtrate. the solid phase was calcined by microwave oven at 800 Watt for 5 minutes to convert the oligocations into its oxide forms. The calcined product and unmodified zeolite were characterized using x-ray diffractometry, FT-IR spectrophotometry, X-ray fluorescence and gas sorption analysis methods to determine their physicochemical properties. Photocatalytic activity of TiO2-zeolite was tested on Alizarin S solution using following method: 50 mg of zeolite was dispersed into 25 mL of 10-4 M Alizarin S. The dispersion was irradiated using 365 nm UV light at room temperature on various irradiation times, i.e. 10, 20, 30, 40 and 60 minutes. At certain irradiation time, the dispersion was filtered and the filtrate was then analyzed its concentration using UV-Vis spectrophotometry method. Characterization results exhibited that the formation of TiO2 on internal as well as external surfaces of zeolite could not be detected  with x-ray diffractometry and FT-IR spectrophotometry, however determination of titanium using x-ray fluorescence analysis on the calcined product showed that the concentration of titanium was much higher than zeolite (0.22% on zeolite and 12.08% on TiO2-zeolite. Gas sorption analysis result indicated that the the calcination  resulted in the increase of specific surface area (16,31 m2/g on zeolite and 100.96 m2/g on TiO2-zeolite as well as total pore volume of calcined product (13.34 mL/Å/g on zeolite and 57.54 mL/Å/g on TiO2-zeolite. The result of photocatalytic activitiy study showed that ca 99 % of Alizarin S was degraded by TiO2-zeolite after UV irradiation for 60 min.   Keywords: TiO2-zeolite, photocatalytic, Alizarin S.

  18. Cr(VI) retention and transport through Fe(III)-coated natural zeolite

    Energy Technology Data Exchange (ETDEWEB)

    Du, Gaoxiang [School of Materials Science and Technology, China University of Geosciences, Beijing 100083 (China); Li, Zhaohui, E-mail: li@uwp.edu [School of Materials Science and Technology, China University of Geosciences, Beijing 100083 (China); Geosciences Department, University of Wisconsin-Parkside, Kenosha, WI 53144 (United States); Department of Earth Sciences, National Cheng Kung University, 1 University Road, Tainan 70101, Taiwan (China); Liao, Libing [School of Materials Science and Technology, China University of Geosciences, Beijing 100083 (China); Hanson, Renee; Leick, Samantha; Hoeppner, Nicole [Geosciences Department, University of Wisconsin-Parkside, Kenosha, WI 53144 (United States); Jiang, Wei-Teh [Department of Earth Sciences, National Cheng Kung University, 1 University Road, Tainan 70101, Taiwan (China)

    2012-06-30

    Graphical abstract: Breakthrough curves of Cr(VI) from columns packed with raw zeolite (a) and Fe(III)-zeolite (b). The solid line in (b) is the HYDRUS-1D fit to the observed data with adsorption term only, while the dashed line in (b) includes a reduction term in the HYDRUS-1D fit. Highlights: Black-Right-Pointing-Pointer Zeolite modified with Fe(III) could be used for adsorption and retention of Cr(VI). Black-Right-Pointing-Pointer The Fe present on zeolite was in an amorphous Fe(OH){sub 3} form. Black-Right-Pointing-Pointer A Cr(VI) adsorption capacity of 82 mg/kg was found on Fe(III)-zeolite. Black-Right-Pointing-Pointer A Cr(VI) retardation factor of 3 or 5 was determined from column and batch studies. - Abstract: Cr(VI) is a group A chemical based on the weight of evidence of carcinogenicity. Its transport and retention in soils and groundwater have been studied extensively. Zeolite is a major component in deposits originated from volcanic ash and tuff after alteration. In this study, zeolite aggregates with the particle size of 1.4-2.4 mm were preloaded with Fe(III). The influence of present Fe(III) on Cr(VI) retention by and transport through zeolite was studied under batch and column experiments. The added Fe(III) resulted in an enhanced Cr(VI) retention by the zeolite with a capacity of 82 mg/kg. The Cr(VI) adsorption on Fe(III)-zeolite followed a pseudo-second order kinetically and the Freundlich adsorption isotherm thermodynamically. Fitting the column experimental data to HYDRUS-1D resulted in a retardation factor of 3 in comparison to 5 calculated from batch tests at an initial Cr(VI) concentration of 3 mg/L. The results from this study showed that enhanced adsorption and retention of Cr(VI) may happen in soils derived from volcanic ash and tuff that contains significant amounts of zeolite with extensive Fe(III) coating.

  19. Synthesis of Zeolites Using the ADOR (Assembly-Disassembly-Organization-Reassembly) Route

    Czech Academy of Sciences Publication Activity Database

    Wheatley, P. S.; Čejka, Jiří; Morris, R. E.

    2016-01-01

    Roč. 2016, č. 110 (2016), č. článku e53463. ISSN 1940-087X R&D Projects: GA ČR GBP106/12/G015 EU Projects: European Commission(XE) 604307 - CASCATBEL Institutional support: RVO:61388955 Keywords : Chemistry * zeolites * synthesis * ADOR mechanism Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 1.232, year: 2016

  20. Picosecond infrared activation of methanol in acid zeolites

    NARCIS (Netherlands)

    Bonn, Miacha; van Santen, Rutger A.; Lercher, J.A.; Kleyn, Aart W.; Bakker, H.J.; Bakker, Huib J.

    1997-01-01

    Highly porous, crystalline zeolite catalysts are used industrially to catalyze the conversion of methanol to gasoline. We have performed a picosecond spectroscopic study providing insights into both the structure and the dynamics of methanol adsorbed to acid zeolites. We reveal the adsorption

  1. Defluorination of drinking water using surfactant modified zeolites ...

    African Journals Online (AJOL)

    This study focused on the removal of fluoridefrom groundwater by employing surfactant modified zeolites (SMZ) synthesized using locallyavailable kaolin material as precursor. The zeolite synthesis involved calcination of kaolin, alkaline fusion and hydrothermal treatment. The final product was modified with 5g/L ...

  2. Assembly-Disassembly-Organization-Reassembly Synthesis of Zeolites Based on cfi-Type Layers

    Czech Academy of Sciences Publication Activity Database

    Firth, D. S.; Morris, S. A.; Wheatley, P. S.; Russell, S. E.; Slawin, A. M. Z.; Dawson, D. M.; Mayoral, A.; Opanasenko, Maksym; Položij, M.; Čejka, Jiří; Nachtigall, P.; Morris, R. E.

    2017-01-01

    Roč. 29, č. 13 (2017), s. 5605-5611 ISSN 0897-4756 R&D Projects: GA ČR GBP106/12/G015 Institutional support: RVO:61388955 Keywords : large-pore zeolite * hydrothermal synthesis * preferential location Subject RIV: CF - Physical ; Theoretical Chemistry OBOR OECD: Physical chemistry Impact factor: 9.466, year: 2016

  3. Calcining natural zeolites to improve their effect on cementitious mixture workability

    International Nuclear Information System (INIS)

    Seraj, Saamiya; Ferron, Raissa D.; Juenger, Maria C.G.

    2016-01-01

    Despite the benefits to long-term concrete durability, the use of natural zeolites as supplementary cementitious materials (SCMs) is uncommon due to their high water demand. The motivation of the research presented here was to better understand how the physical and chemical characteristics of natural zeolites influenced the workability of cementitious mixtures and whether those properties could be modified through calcination to mitigate the high water demand of natural zeolites. In this research, three different natural zeolites were characterized in their original and calcined states using x-ray diffraction (XRD) and Brunauer–Emmett–Teller (BET) surface area measurements. Rheology experiments were then conducted on cementitious pastes containing these natural zeolites, in their original and calcined states, to assess mixture viscosity and yield stress. Results showed that calcination destabilized the structure of the natural zeolites and reduced their surface area, which led to an improvement in mixture viscosity and yield stress.

  4. Fly ash based zeolitic pigments for application in anticorrosive paints

    International Nuclear Information System (INIS)

    Shaw, Ruchi; Tiwari, Sangeeta

    2016-01-01

    The purpose of this work is to evaluate the utilization of waste fly ash in anticorrosive paints. Zeolite NaY was synthesized from waste fly ash and subsequently modified by exchanging its nominal cation Na + with Mg 2+ and Ca 2+ ions. The metal ion exchanged zeolite was then used as anticorrosive zeolitic pigments in paints. The prepared zeolite NaY was characterized using X-Ray diffraction technique and Scanning electron microscopy. The size, shape and density of the prepared fly ash based pigments were determined by various techniques. The paints were prepared by using fly ash based zeolitic pigments in epoxy resin and the percentages of pigments used in paints were 2% and 5%. These paints were applied to the mild steel panels and the anticorrosive properties of the pigments were assessed by the electrochemical spectroscopy technique (EIS).

  5. Biogas cleaning and upgrading with natural zeolites from tuffs.

    Science.gov (United States)

    Paolini, Valerio; Petracchini, Francesco; Guerriero, Ettore; Bencini, Alessandro; Drigo, Serena

    2016-01-01

    CO2 adsorption on synthetic zeolites has become a consolidated approach for biogas upgrading to biomethane. As an alternative to synthetic zeolites, tuff waste from building industry was investigated in this study: indeed, this material is available at a low price and contains a high fraction of natural zeolites. A selective adsorption of CO2 and H2S towards CH4 was confirmed, allowing to obtain a high-purity biomethane (CO2 biogas samples were used, and no significant effects due to biogas impurities (e.g. humidity, dust, moisture, etc.) were observed. Thermal and vacuum regenerations were also optimized and confirmed to be possible, without significant variations in efficiency. Hence, natural zeolites from tuffs may successfully be used in a pressure/vacuum swing adsorption process.

  6. Synthesis of Zeolite-X from Bottom Ash for H2 Adsorption

    Science.gov (United States)

    Kurniawan, R. Y.; Romadiansyah, T. Q.; Tsamarah, A. D.; Widiastuti, N.

    2018-01-01

    Zeolite-X was synthesized from bottom ash power plant waste using fusion method on air atmosphere. The fused product dissolved in demineralized water and aluminate solution was added to adjust the SiO2/Al2O3 molar ratio gel prior hydrothermal process. The synthesis results were characterized using X-Ray Diffraction (XRD), Scanning Electron Microscope (SEM), and Fourier Transform Infrared (FTIR). The results showed that the zeolite-X has a high crystallinity with octahedral particle. The pure-form zeolite-X then was characterized and tested for H2 gas adsorption by gravimetric method to determine the H2 gas adsorption capacity of zeolite-X from bottom ash and it was compared to synthetic zeolite-X.

  7. Effects of copper on the sabellid polychaete, Eudistylia vancouveri. II. copper accumulation and tissue injury in the branchial crown

    Energy Technology Data Exchange (ETDEWEB)

    Young, J S [Pacific Northwest Lab., Sequim, WA; Adee, R R; Piscopo, I; Buschbom, R L

    1981-01-01

    Copper in seawater caused injury to the radioles (gills) of the sabellid polychaete, Eudistylia vancouveri. Light and electron microscopy showed the loss of cellular adhesion and the structural derangement that lead to cell necrosis and death. The progression of injury was related to the uptake of copper into the tissues. Copper was found by X-ray microanalysis to be localized subcellularly in membrane-bound vesicles that are similar to lysosomes. Cell breakdown may result from lysosmal labilization.

  8. Influence of zeolite nanofillers on properties of polymeric materials

    OpenAIRE

    Kopcová, M.; Ondrušová, D.; Krmela, J.; Průša, P.; Pajtášová, M.; Jankurová, Z.

    2012-01-01

    The present work deals with the preparation and study of modified polymeric materials with the replacement of carbon black by nanofillers on the basis of zeolite that is environmentally friendly. Natural zeolites from a group of aluminosilicate nanoporous materials have wide range of possibilities for applications that are environmentally friendly. Zeolites can be used in the role of fillers into the polymer materials too [1]. The given work deals with the preparation and study of modif...

  9. Copper and copper-nickel-alloys - An overview

    Energy Technology Data Exchange (ETDEWEB)

    Klassert, Anton; Tikana, Ladji [Deutsches Kupferinstitut e.V. Am Bonneshof 5, 40474 Duesseldorf (Germany)

    2004-07-01

    With the increasing level of industrialization the demand for and the number of copper alloys rose in an uninterrupted way. Today, the copper alloys take an important position amongst metallic materials due to the large variety of their technological properties and applications. Nowadays there exist over 3.000 standardized alloys. Copper takes the third place of all metals with a worldwide consumption of over 15 millions tons per year, following only to steel and aluminum. In a modern industrial society we meet copper in all ranges of the life (electro-technology, building and construction industry, mechanical engineering, automotive, chemistry, offshore, marine engineering, medical applications and others.). Copper is the first metal customized by humanity. Its name is attributed to the island Cyprus, which supplied in the antiquity copper to Greece, Rome and the other Mediterranean countries. The Romans called it 'ore from Cyprus' (aes cyprium), later cuprum. Copper deposited occasionally also dapper and could be processed in the recent stone age simply by hammering. Already in early historical time copper alloys with 20 to 50 percent tin was used for the production of mirrors because of their high reflecting power. Although the elementary nickel is an element discovered only recently from a historical perspective, its application in alloys - without any knowledge of the alloy composition - occurred at least throughout the last 2.000 years. The oldest copper-nickel coin originates from the time around 235 B.C.. Only around 1800 AD nickel was isolated as a metallic element. In particular in the sea and offshore technology copper nickel alloys found a broad field of applications in piping systems and for valves and armatures. The excellent combination of characteristics like corrosion resistance, erosion stability and bio-fouling resistance with excellent mechanical strength are at the basis of this success. An experience of many decades supports the use

  10. Study of the ortho-positron annihilation process in zeolite Y

    International Nuclear Information System (INIS)

    Alvarado D, M. E.

    2010-01-01

    For several years a great interest has existed for the study of the natural and synthetic zeolites due to its properties. The porosity, one of their main characteristics allows that these materials are used as molecular sieves, catalysts, gases drying, etc. In order to investigating the porosity and other zeolite properties one carries out the study of the process of positron annihilation lifetime spectroscopy (Pals). This is a technique that provides information about the size and the pores form since is highly sensitive to the free volume and the superficial area of those porous materials as the zeolites. The study began with the elaboration of zeolite Y tablets in a hydraulic press where different pressures (from 0 to 1.26 GPa) and masses (70, 80 and 100 mg) were proven to obtain the estimate porosity of each tablet. A graph was elaborated and the effect of the mass and pressure with regard to the zeolite porosity was analyzed. Later on, the powder and tablets of 70 mg were characterized by means of X-ray diffraction (the glass size, interplanar distance, length and the volume of the unitary cell); scanning electron microscopy (the particles size and morphology); thermo gravimetric analysis (dehydration temperature and the stability up to 700 C) and the Brunauer Emmett Teller method (specific area). After the zeolite Y tablets characterization was carried out the positron annihilation process by means of Pals where its free volume of zeolite Y was analyzed, which includes to the structural cavities and the interparticle volume. The powdered zeolite was analyzed to different experimental conditions (preparation of the sample and the Pals equipment) to obtain the optimal conditions (a window with a time of 400 ns and a enlarged energy window) of analysis. On the other hand, the tablets were analyzed under optimal conditions to obtain the four components of time and intensity (τ, Ι), result of the different ways of positrons annihilation in the zeolite. These

  11. Densification of salt-occluded zeolite a powders to a leach-resistant monolith

    International Nuclear Information System (INIS)

    Lewis, M.A.; Fischer, D.F.; Murhpy, C.D.

    1993-01-01

    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 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, 2 d. Thus, the bonded zeolite may be a suitable waste form for IFR salt waste

  12. Theoretical determination of proton affinity differences in zeolites

    NARCIS (Netherlands)

    Kramer, G.J.; Santen, van R.A.

    1993-01-01

    An important factor in zeolite catalysis is the proton affinity, i.e., the energy required to remove a proton from the zeolite lattice. Differences in proton affinity are expected to influence the catalytic activity of acid sites, making the catalytically active sites inhomogeneous (within one

  13. Dietary effects of Ca-zeolite supplementation on some blood and ...

    African Journals Online (AJOL)

    smyo

    to the Al, Si, Zn, Na or K concentrations of zeolite, because these minerals have been ... The SiO2, Al2O3, H2O related to loss on ignition, and CaO are the essential ...... The effect of interaction between narasin and nicarbazin with zeolite ... Protective role of zeolite on short- and long-term lead toxicity in the teleost fish.

  14. Studi Hubungan Struktur Mikro dan Keaktifan Zeolit Alam Akibat Proses Pengasaman

    Directory of Open Access Journals (Sweden)

    Made Cuaca Vahindra Suriawan

    2012-11-01

    Full Text Available Natural zeolite is known as metal pollutant adsorbent in industrial waste treatment. As initial study for utilization ofnatural zeolite from Indonesia for metal pollutants adsorbent in liquid waste, then the physical properties should berecognized first. Activation is the first step in order to the natural zeolite able to adsorb the metal pollutants in the waste.One method to activate is by applying acid solution such as sulfuric acid (H2SO4 to activate the natural zeolite. The purposeof this research is to observe the change on microstructure of natural zeolite obtained from the mining at Tasikmalaya, WestJava, Indonesia due to chemical activated, to be compared to one without chemical activation. The variation of concentrationof H2SO4 namely: 2 4 , 6, 8, and 10 % , with 30 minutes soaking time , in a room temperatur. The microstructure then isobserved by using optical microscope following standard for ceramography. The change in microstructure then is analyzedand studied to be related with the ability of natural zeolite in adsorb the metal pollutant. The level activity of the zeolite canbe recognized by measuring its porosity.

  15. Stability of krypton fixed in zeolite-3A and -5A

    International Nuclear Information System (INIS)

    Matsuoka, Shingo; Nakamura, Hirone; Tamura, Takaaki; Takano, Takemi; Ito, Yasuo; Sugawara, Ichiro.

    1986-01-01

    The fixation operation was carried out at 450 ∼ 650 deg C, 1,000 atm for 24 h. The amount of fixed Kr was measured using thermal neutron activation analysis. For zeolite-3A the amount of Kr fixed decreased from 20 to 5 w/o as the fixation temperature rose. In the case of zeolite-5A, Kr fixation was observed at 550 deg C and above, and the amount increased to 15 w/o as the temperature rose to 650 deg C. The diffusion coefficient of Kr in the zeolite was determined from the result of heating tests. The value obtained was substituted in a diffusion equation, enabling us to predict the Kr release behavior at any temperature in a dry atmosphere. Both the samples of zeolite-3A fixed below 525 deg C and of zeolite-5A below 625 deg C showed an intensive Kr release in water that would not be expected from the release behavior under dry conditions. However, such unexpected release was not observed in either sample fixed above these respective temperatures. This could be accounted for by the fact that zeolite cations move easily when zeolite is moisturized. (author)

  16. Synthesis of type A zeolite from calcinated kaolin

    International Nuclear Information System (INIS)

    Rodrigues, E.C.; Neves, R.F.; Souza, J.A.S.; Moraes, C.G.; Macedo, E.N.

    2011-01-01

    The mineral production has caused great concern in environmental and industrial scenario due to the effects caused to the environment. The industries of processing kaolin for paper are important economically for the state of Para, but produce huge quantities of tailings, which depend on large areas to be stocked. This material is rich in silico-aluminates can be recycled and used as raw material for other industries. The objective is to synthesize zeolite A at different temperatures of calcination and synthesis. The starting materials and synthesis of zeolite A have been identified and characterized through analysis of X-ray diffraction (DRX) and scanning electron microscopy (MEV). The synthesis process of zeolite A, using as source of silica and the aluminum metakaolin, which was calcined at temperatures of 700 ° C and 800 ° C for 2 hours of landing in a burning furnace type muffle. Observed in relation to the calcination of kaolin as the main phase, the metakaolin. This is just a removal of water from its structure, so we opted for the lower temperature, less energy consumption. The synthesis process of zeolite A, produced good results for the formation of zeolites type A, which were characterized with high purities. (author)

  17. Processing of radioactive waste solution with zeolites, (4)

    International Nuclear Information System (INIS)

    Mimura, Hitoshi; Kanno, Takuji

    1978-01-01

    Volatilization of Cs from Cs type zeolites and calcined zeolites were studied at high temperature. Synthetic zeolites A, X, Y, synthetic mordenite (Zeolon), natural mordenite and clinoptilolite saturated with Cs were used in this study. Volatilized Cs from CsX was largest in quantity and from cs type natural zeolites smallest. Volatilization of Cs was observed at about 800 0 C and increased as the calcining temperature rose. Volatilized Cs from CsA was smallest in synthetic zeolites. CsA recrystallized to nepheline and pollucite with the ratio of about 1 : 1 above 1,000 0 C and it seemed that the volatilization of Cs from pollucite was suppressed with the nepheline phase surrounded them. The rate of volatilization was very fast within the initial 10 min and very slow after 60 min except for CsX. This behavior suggested that the rate was very fast before structural transformation. The mean volatilization rate of Cs in 3 hr from calcined CsX (pollucite) was 1.1 x 10 -4 mg/cm 2 .min and the others were 10 -5 -- 10 -6 mg/cm 2 .min. The amount of volatilized Cs in Ar flow was decreased 20 -- 90% of that in air flow. Volatilized species was identified with Cs 2 O by mass spectrometry. (auth.)

  18. Characteristics of mordenite-type zeolite catalysts deactivated by SO{sub 2} for the reduction of NO with hydrocarbons

    Energy Technology Data Exchange (ETDEWEB)

    Kim, M.H.; Nam, I.S.; Kim, Y.G. [Pohang Univ. of Science and Technology/Research Inst. of Industrial Science and Technology, Pohang (Korea, Republic of)

    1998-10-25

    The deactivation of mordenite-type zeolite catalysts for the selective reduction of NO by hydrocarbons in the presence of SO{sub 2} was examined in a packed-bed flow reactor system. The physicochemical properties of the deactivated catalysts by SO{sub 2} were extensively characterized by TGA, TPSR, XPS, Raman, XANES, the measurements of surface area and elemental analysis. Not only the surface area and sulfur content of the deactivated catalysts, but their TGA and TPSR patterns strongly suggest the formation of a sulfur species as a deactivating agent on the catalyst surface. It is also observed that the sulfur species exists in the form of sulfate (SO{sub 4}{sup 2{minus}}) by XPS and Raman. It mainly causes the loss of NO removal activity of the catalysts. The sulfate species formed on the deactivated catalysts by SO{sub 2} did not significantly alter the chemical environment of the copper ions contained in the zeolite catalysts such as CuHM and CuNZA. It does not exist in the form of cupric sulfate pentahydrate on the catalyst surface as revealed by Cu K-edge absorption spectra of the catalysts.

  19. Uranium,Radium and Iron Absorption from Liquid Waste Uranium Ore Processing by Zeolite

    International Nuclear Information System (INIS)

    Wismawati, T; Sorot sudiro, A; Herjati, T

    1998-01-01

    The aim of this work is to determine zeolites sorption capacity and the distribution coefficient of uranium, radium, and iron in zeolite-liquid waste system. Mineralogical composition of zeolite used in the experiment has been determine by examining the thin sections of zeolite grains under a microscope. Zeolite has ben activated by the dilute sulfuric acid or sodium hydroxide solution. The results show that the use of 0.25 N sodium hydroxide solution could be optimizing the zeolite for uranium and iron ions sorption and that of 0.1 N sulfuric acid solution is for radium sorption. The re-activation process has been carried out in three hours. Under such a condition, the sorption efficiency of zeolite to those ions have been known to be 45.85% for uranium, 96.63 % for iron and 87.80 % for radium. The distribution coefficients of uranium, radium and iron ion in zeolite-liquid waste system have been calculated 0.85, 7.02, and 28.65 ml/g respectively

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

    Energy Technology Data Exchange (ETDEWEB)

    Ayoub, Muhammad, E-mail: muhammad.ayoub@petronas.com.my [Department of Chemical Engineering, Universiti Teknologi PETRONAS, 31750, Tronoh, Perak, Malaysia and School of Chemical Engineering, Universiti Sains Malaysia, 43000, Pinang (Malaysia); Abdullah, Ahmad Zuhairi, E-mail: chzuhairi@usm.my [School of Chemical Engineering, Universiti Sains Malaysia, 43000, Pinang (Malaysia); Inayat, Abrar, E-mail: abrar.inayat@petronas.com.my [Department of Chemical Engineering, Universiti Teknologi PETRONAS, 31750, Tronoh, Perak (Malaysia)

    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.

  1. Characterization of natural and modified zeolites using ion beam analysis techniques

    Energy Technology Data Exchange (ETDEWEB)

    Andrade, E. [Instituto de Fisica, Departamento de Fisica Experimental, Universidad Nacional Autonoma de Mexico, Apdo. Postal 20-364, 01000 (Mexico)], E-mail: andrade@fisica.unam.mx; Solis, C. [Instituto de Fisica, Departamento de Fisica Experimental, Universidad Nacional Autonoma de Mexico, Apdo. Postal 20-364, 01000 (Mexico); Aceves, J.M.; Miranda, R. [Facultad de Estudios Superiores Cuautitlan Itzcalli, Departamento de Quimica, Universidad Nacional Autonoma de Mexico, 1 de Mayo S/N, Cuatitlan Itzcalli, Edo. de Mexico, C.P. 74540 (Mexico); Cruz, J. [Instituto de Fisica, Departamento de Fisica Experimental, Universidad Nacional Autonoma de Mexico, Apdo. Postal 20-364, 01000 (Mexico); Rocha, M.F. [Escuela Superior de Ingenieria Mecanica y Electrica, Instituto Politecnico Nacional, U.P. ' Adolfo Lopez Mateos' , Zacatenco, Del. Gustavo A. Madero, Mexico D.F. 07738 (Mexico); Zavala, E.P. [Instituto de Fisica, Departamento de Fisica Experimental, Universidad Nacional Autonoma de Mexico, Apdo. Postal 20-364, 01000 (Mexico)

    2008-05-15

    Zeolites are very important materials in catalytic and industrial processes. Natural, modified and synthetic zeolites have a wide range of uses because of their good adsorption, ion exchange capacity and catalytic properties. Mexico is an import source of natural zeolites, however their utilization in the natural form is limited due to the presence of trace metallic impurities. For example, metals such as vanadium and chromium inhibit the elimination of sulfur in hydrocarbons. Therefore, it is important to know the precise composition of the zeolite material. In this work, we report the elemental characterization of zeolites using various IBA techniques. {sup 3}He{sup +} and {sup 2}H{sup +} beams were used to measure the major element concentrations (Si, Al, O, C) by RBS and NRA. PIXE and SEM-EDS were used to measure the total trace element content (V, Cr, Fe, Ni, Cu, Zn, Rb, Sr, Zr, Pb, etc). Additionally, XRD was used to study the zeolite crystal structure.

  2. PEMANFAATAN ZEOLIT DARI ABU SEKAM PADI DENGAN AKTIVASI ASAM UNTUK PENURUNAN KESADAHAN AIR

    Directory of Open Access Journals (Sweden)

    VH Putranto

    2016-04-01

    Full Text Available Aktivasi menggunakan asam kuat dalam sintesis zeolit dikenal dapat meningkatkan kemampuan zeolit sebagai adsorben. Penelitian ini bertujuan untuk memanfaatkan abu sekam padi sebagai sumber silika yang diaktivasi dengan HCl 2 M pada sintesis zeolit secara hidrotermal dan memanfaatkan zeolit hasil sintesis untuk menurunkan tingkat kesadahan air sumur. Proses aktivasi dilakukan dengan menggunakan larutan HCl 2 M. Zeolit hasil sintesis diuji secara kualitatif menggunakan Spektrofotometer Inframerah (FTIR dan Difraksi Sinar-X (XRD kemudian dimanfaatkan untuk menurunkan kadar ion logam Ca2+ dan Mg2+ penyebab kesadahan air dengan variasi waktu kontak (0, 20, 30, 40, 50, 60, 90, dan 120 menit dilanjutkan variasi massa zeolit sintetis (0,05; 0,1; 0,125; 0,25; serta 0,5 gram per volume air sumur 25 ml. Hasil uji komposisi kimia dengan Fluoresensi Sinar-X menunjukkan abu sekam padi yang telah diaktivasi memiliki kadar silika (SiO2 yang lebih tinggi yakni mencapai 95,83%. Hasil penelitian menunjukkan bahwa zeolit sintetis yang dihasilkan merupakan zeolit tipe NaY (zeolite like dengan kristal cancrinite sebagai fasa dominan. Adsorbsi optimum ion logam Ca2+ dan Mg2+ dalam air sumur oleh zeolit hasil sintesis terjadi pada waktu 60 menit dengan penyerapan optimum sebesar 94,71% Ca2+ dan 84,55% Mg2+ serta pada massa adsorben optimum 0,125 gram dengan penyerapan optimum sebesar 93,02% Ca2+ dan 83,78% Mg2+.Activation using a strong acid in zeolite synthesis is known can enhance the ability of zeolite as adsorbent. This study aims to utilize rice husk ash as a source of silica, which is activated with 2 M HCl in zeolite synthesis hydrothermally and apply the zeolite to reduce the level of hardness in well water. The activation process is performed by using HCl 2 M solution. Zeolite product is analyzed qualitatively using infrared spectrometer (FTIR and X-ray Diffraction (XRD and then used to reduce the levels of metal ions Ca2+ and Mg2+ which cause water hardness

  3. Ammonia, phosphate, phenol, and copper(II) removal from aqueous solution by subsurface and surface flow constructed wetland.

    Science.gov (United States)

    Mojiri, Amin; Ahmad, Zakiah; Tajuddin, Ramlah Mohd; Arshad, Mohd Fadzil; Gholami, Ali

    2017-07-01

    Water pollution is a global problem. During current study, ammonia, phosphate, phenol, and copper(II) were removed from aqueous solution by subsurface and surface flow constructed wetland. In current investigation, distilled water was polluted with four contaminants including ammonia, phosphate, copper (Cu), and phenol. Response surface methodology and central composite design were applied to optimize pollutant removal during treatment by subsurface flow constructed wetland (SSFCW). Contact time (12 to 80 h) and initial pollutant concentration (20 to 85 mg/L) were selected as independent factors; some upper and lower ranges were also monitored for accuracy. In SSFCW, water hyacinth transplanted in two substrate layers, namely zeolite and cockle shell. SSFCW removed 87.7, 81.4, 74.7, and 54.9% of ammonia, phosphate, Cu, and phenol, respectively, at optimum contact time (64.5 h) and initial pollutant concentration (69.2 mg/L). Aqueous solution was moved to a surface flow constructed wetland (SFCW) after treating via SSFCW at optimum conditions. In SFCW, Typha was transplanted to a fixed powdered substrate layer, including bentonite, zeolite, and cockle shell. SFCW could develop performance of this combined system and could improve elimination efficacy of the four contaminants to 99.99%. So this combined CW showed a good performance in removing pollutants. Graphical abstract Wetlands arrangement for treating aqueous solution in current study.

  4. Antibacterial properties of Ag-exchanged Philippine natural zeolite-chitosan composites

    Science.gov (United States)

    Taaca, Kathrina Lois M.; Olegario, Eleanor M.; Vasquez, Magdaleno R.

    2017-12-01

    Zeolites are microporous minerals composed of silicon, aluminum and oxygen. These aluminosilicates consist of tetrahedral units which produce open framework structures to generate a system of pores and cavities of molecular dimensions. Zeolites are naturally abundant and can be mined in most parts of the world. In this study, natural zeolites (NaZ) which are locally-sourced here in the Philippines were investigated to determine its properties. An ion-exchange process was utilized, using the zeolite to silver (Ag) solution ratio of 1:20 (w/v), to incorporate Ag into the zeolite framework. Characterizations such as XRD, AAS, and Agar diffusion assay were used to evaluate the properties of the synthesized Ag-exchanged zeolites (AgZ). X-ray diffraction revealed that both NaZ and AgZ have peaks mostly corresponding to the clinoptilolite structure, with some trace peaks of the mordenite and quartz. Absorption spectroscopy revealed that the ion exchange process added about 0.61188g of silver into the zeolite structure. This Ag content was seen to be enough to make the AgZ sample exhibit an antibacterial effect where clearing zones against E. coli and S. aureus were observed in the agar diffusion assay, respectively. The AgZ sample was also tested as ceramic filler to a polymer matrix-chitosan. The diffusion assay revealed presence of antibacterial activity to the polymer composite with AgZ fillers. These results indicate that the Philippine natural zeolite, incorporated with metals such as Ag, can be used as an antibacterial agent and can be developed as a ceramic filler to improve the antibacterial property of composite materials for biomedical application.

  5. Ru complexes of Hoveyda–Grubbs type immobilized on lamellar zeolites: activity in olefin metathesis reactions

    Czech Academy of Sciences Publication Activity Database

    Balcar, Hynek; Žilková, Naděžda; Kubů, Martin; Mazur, Michal; Bastl, Zdeněk; Čejka, Jiří

    2015-01-01

    Roč. 11, NOV 2015 (2015), s. 2087-2096 ISSN 1860-5397 Institutional support: RVO:61388955 Keywords : Hoveyda-Grubbs type catalyst * hybrid catalysts * lamellar zeolites Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 2.697, year: 2015

  6. Langmuir and Freundlich Isotherm Adsorption Equations for Chromium (VI) Waste Adsorption by Zeolite

    International Nuclear Information System (INIS)

    Murni Handayani; Eko Sulistiyono

    2009-01-01

    The research of chromium (VI) waste adsorption by zeolite has done. Wastes which are produced by Industries, both radioactive waste and heavy metal waste need done more processing so that they are not endanger environment and human health. Zeolite has very well-ordered crystal form with cavity each other to way entirely so that cause surface wide of zeolite become very big and very good as adsorbents. This research intends to know appropriate isotherm adsorption method to determine maximum capacity of zeolite to chromium (VI) waste. The equations which used in adsorption process are Langmuir and Freundlich isotherm Adsorption equations. The instrument was used in adsorption process by using Atomic Adsorption Spectroscopy (AAS). The experiment result showed that the biggest mass of chromium (VI) metal ion which was absorb by zeolite in 20 ppm concentration was 7.71 mg/gram zeolite. Adsorption process of Chromium (VI) waste by zeolite followed Langmuir and Freundlich isotherm equations with R 2 >0,9 . Appropriate equation to determine maximum adsorption capacity of zeolite for chromium (VI) waste adsorption is Langmuir equation. The maximum adsorption capacity of zeolite is 52.25 mg/gram. (author)

  7. Environmental applications of natural zeolitic materials based on their ion-exchange properties

    International Nuclear Information System (INIS)

    Colella, C.

    1998-01-01

    Natural zeolites, such as clinoptilolite, chabazite, phillipsite and mordenite, exhibit good selectivities for some water pollutants, e.g., Cs + , NH 4 + and Pb 2+ . Zeolite-rich tuffs may be therefore utilized for removing the above and other cations from wastewaters before discharge. Continuous processes with fixed beds are usually employed for water purification, such as those in service in the U.S.A for ammonium removal from municipal sewage. Direct action of the ion exchanger is needed when the pollutant must be removed from soil and trapped in the zeolite framework. Discontinuous processes (addition of zeolite to the waste solution) are also possible, provided the polluted zeolitic sludge is stabilized-solidified in a cement matrix matrix before disposal. Removal of radionuclides from nuclear power plant waters with natural zeolites is discussed

  8. Magnetic zeolites a and p synthesized from kaolin: synthesis and characterization

    Energy Technology Data Exchange (ETDEWEB)

    Bessa, R.A.; Oliveira, C.P.; Nascimento, R.F.; Bohn, F.; Loiola, A.R. [Universidade Federal do Ceara (UFCE), CE (Brazil)

    2016-07-01

    Full text: Zeolites are hydrated aluminosilicates of open chain, formed by silica and alumina tetrahedral structures linked by common oxygen atoms, generating interconnected pores and cages with molecular dimensions and well defined sizes that limit matter transference between internal surface and application medium. They can be found naturally or synthesized using different aluminum and silicon sources that may modify the produced zeolite. Their industrial application has grown enormously over the last century. However, a big issue that still remains is the difficulty in retrieving zeolite powders when used in aqueous media. This work reports the use of kaolin as an alternative raw material for zeolite syntheses by means of hydrothermal route and subsequent preparation of magnetic composites through magnetite impregnation. The syntheses of two different zeolites were carried out by mixing appropriate amounts of metakaolin (kaolin previously calcined at 600 deg C for 2 h), sodium metasilicate and sodium hydroxide solution, aged for 18 h and heated at 100 °C for 4-48 h. After these processes, the final materials were washed several times with distilled water, filtered and dried at 80 deg C for 12 h. Magnetic composites were prepared by impregnating the zeolites with of Fe3O4 nanoparticles (NP) synthesized by the partial oxidation and precipitation of Fe2+ ions. The obtained materials were characterized by X-ray diffraction, scanning electron microscopy, FTIR spectroscopy and magnetization measurements. The results of XRD and FTIR provide evidence of the success in the synthesis of both zeolites A and P as well as Fe3O4. Subsequently, composites were formed by mixtures of zeolite A + NP and zeolite P + NP. The existence of secondary crystalline phases was also confirmed. However, it did not interfered significantly in the results as these phases appear as minor amounts and are most likely residues from the clay used as the main silica and alumina sources. Scanning

  9. Catalytic Cracking of Used Palm Oil using Composite Zeolite

    International Nuclear Information System (INIS)

    Chang, W.H.; Tye, C.T.

    2013-01-01

    The rapid expansion of human society implies greater energy demand and environmental issues. In face of depletion energy resources, research is being carried out widely in order to convert the plant oil into biofuel. In this research, the production of liquid biofuels via catalytic cracking of used palm oil in the presence of composite zeolite was studied. The performance of composite zeolite of different properties in the reaction has been evaluated. The catalytic cracking reactions were carried out in a batch reactor at reaction temperature of 350 degree Celsius for an hour. In the present study, adjusting the ratio of meso porous coating to microporous zeolite and magnesium loading on composite zeolite catalyst were found to be able to increase the gasoline fraction and overall conversion of the reaction. (author)

  10. Directing factors affecting the synthesis of a MFI-type zeolite

    Energy Technology Data Exchange (ETDEWEB)

    Vinaches, P.; Pergher, S.B.C. [Universidade Federal de Rio Grande do Norte (UFRN), RN (Brazil); Lopes, C.W. [Institute of Chemical Technology, Mumbai (India); Gomez-Hortiguela, L. [Instituto de Catalisis y Petroleoquimica, Madrid (Spain); Finger, P.H.; Silva, B.A. da; Dallago, R.M.; Mignoni, M.L. [Universidade Regional Integrada do Alto Uruguai e das Missoes (URI), Erechim, RS (Brazil)

    2016-07-01

    Full text: Zeolites are crystalline tectosilicates constituted by (TO4) tetrahedra connected through the oxygens of their vertices. The importance of these materials is that their properties differ, due to their variable compositions and structures, leading to the possibility of applying them into different industries, for example, as catalyst in petroleum industry or sensors in quality control. One of the big questions in this area is about the understanding of the chemistry that directs to one or another type of zeolite. Another important question is the search of new zeolitic structures for new applications. One approach to answer both is the study of the structure-directing agents, which are inorganic or organic molecules used in the synthesis of zeolites. New and already-used molecules have been studied within different synthesis conditions and different techniques, as characterization or computational studies. And several attempts of rationalization were and, still, will be performed. In this research, an imidazolium-based compound was studied in hydrothermal zeolite synthesis as organic structure-directing agent (OSDA). The products were obtained with Si/Al or Si/(Al+Zn) compositions, proved by ICP data. X-ray diffractograms showed two different zeolitic types: MFI and TON. It was observed that when Zn was present in the synthesis gel, pure MFI phases were able to appear. But in his absence, the products were all mixtures of MFI and TON zeolites. It was also possible to distinguish both phases by SEM micrographs, as MFI had brick-like shape and TON appeared as needles. The obtained zeolites were stable until 900°C minimum, as tested by a TG/DTG/DSC experiment. To prove that the chosen OSDA directed these structures, a CHN analysis was performed, resulting in integrity of the molecules inside the zeolitic pores and cavities. Finally, a rationale about the location and conformation of the OSDA was needed to understand these experimental results. So, it was

  11. Directing factors affecting the synthesis of a MFI-type zeolite

    International Nuclear Information System (INIS)

    Vinaches, P.; Pergher, S.B.C.; Lopes, C.W.; Gomez-Hortiguela, L.; Finger, P.H.; Silva, B.A. da; Dallago, R.M.; Mignoni, M.L.

    2016-01-01

    Full text: Zeolites are crystalline tectosilicates constituted by (TO4) tetrahedra connected through the oxygens of their vertices. The importance of these materials is that their properties differ, due to their variable compositions and structures, leading to the possibility of applying them into different industries, for example, as catalyst in petroleum industry or sensors in quality control. One of the big questions in this area is about the understanding of the chemistry that directs to one or another type of zeolite. Another important question is the search of new zeolitic structures for new applications. One approach to answer both is the study of the structure-directing agents, which are inorganic or organic molecules used in the synthesis of zeolites. New and already-used molecules have been studied within different synthesis conditions and different techniques, as characterization or computational studies. And several attempts of rationalization were and, still, will be performed. In this research, an imidazolium-based compound was studied in hydrothermal zeolite synthesis as organic structure-directing agent (OSDA). The products were obtained with Si/Al or Si/(Al+Zn) compositions, proved by ICP data. X-ray diffractograms showed two different zeolitic types: MFI and TON. It was observed that when Zn was present in the synthesis gel, pure MFI phases were able to appear. But in his absence, the products were all mixtures of MFI and TON zeolites. It was also possible to distinguish both phases by SEM micrographs, as MFI had brick-like shape and TON appeared as needles. The obtained zeolites were stable until 900°C minimum, as tested by a TG/DTG/DSC experiment. To prove that the chosen OSDA directed these structures, a CHN analysis was performed, resulting in integrity of the molecules inside the zeolitic pores and cavities. Finally, a rationale about the location and conformation of the OSDA was needed to understand these experimental results. So, it was

  12. Thermophysical properties of novel zeolite materials for sorption cycles

    KAUST Repository

    Thu, Kyaw; Kim, Youngdeuk; Xi, Baojuan; Ismail, Azhar Bin; Ng, K. C.

    2013-01-01

    his article discusses the thermophysical properties of zeolite-based adsorbents. Three types of zeolite (Z-01, Z-02 and Z-05) with different chemical compositions developed by Mitsubishi Plastics, Inc. are analyzed for possible applications

  13. Multicomponent liquid ion exchange with chabazite zeolites

    International Nuclear Information System (INIS)

    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

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

    Science.gov (United States)

    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...

  15. Using zeolites for fixation and long-term storage of krypton

    International Nuclear Information System (INIS)

    Pirogova, G.N.; Voronin, Yu.V.; Pribylov, A.A.; Serpinskii, V.V.; Mirskii, Ya.V.; Almazova, B.B.; Golitsina, V.V.

    1993-01-01

    It is known that large quantities of 85 Kr are liberated during the operation of nuclear power plants and, in particular, during the processing of nuclear fuel. At the present time, there are several methods of its fixation (accumulation), viz., storage in high-pressure gas balloons, adsorption, plasma-aided implantation into metals, introduction into clathrate compounds, and obtaining kryptonates. Encapsulation in zeolites is one of the most promising methods. The merits of this method include safety during storage, a favorable volume-to-mass ratio, the possibility of separating krypton from a mixture of different gases, and purity of the encapsulated gas. The encapsulation technique has been developed quite recently. Several recent reports established the possibility of encapsulating krypton in the 3A-type zeolites. However, most of the investigators observed leakage during the storage of the zeolite-gas system and complete liberation of krypton from the zeolite during prolonged storage. This paper deals with a study of the encapsulation process of krypton in the zeolites obtained by cation exchange from NaA. The experimental specimens were characterized by the degree of exchange of sodium into potassium and cesium. It is known that the introduction of cesium into the structure (body) of a zeolite reduces the size of the window of entrance. All the synthesized specimens were used in their granulated form. The aim of this study was to develop zeolite specimens for carrying out long-term storage of krypton

  16. Corrosion of copper-based materials in gamma radiation

    International Nuclear Information System (INIS)

    Yunker, W.H.

    1986-06-01

    The corrosion behaviors of pure copper (CDA 101), 7% aluminum-copper bronze (CDA 613) and 30% nickel-copper (CDA 715) are being studied in a gamma radiation field of 1 x 10 5 R/h. These studies are in support of the Nevada Nuclear Waste Storage Investigations (NNWSI) Project, by Lawrence Livermore National Laboratory (LLNL), of copper-based materials for possible use in container systems for the permanent geologic burial of nuclear waste. Weight loss, tear drop (stressed), and crevice specimens of the three materials were exposed to water vapor-air atmospheres at 95 0 C and 150 0 C and to liquid water at 95 0 C for periods of one, three, and six months. Longer exposures are in progress. Measurements include: changes in the chemical composition of the gas and water, specimen weight changes, oxide film weights, evidence of microcracking and crevice corrosion, and chemical composition of the oxide films by Auger electron spectroscopy and x-ray diffraction. Interim results show considerable pit and under-film corrosion of alloys CDA 613 and CDA 715. Uniform corrosion rates range from 0.012 mil/yr (0.30 μm/yr) to 0.22 mil/yr (5.6 μm/yr), based on specimen weight losses during six- and seven-month exposures. The time dependencies will be determined as more data become available

  17. An innovative zinc oxide-coated zeolite adsorbent for removal of humic acid

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Lingling, E-mail: lasier_wang@hotmail.com [College of Chemical Engineering and Materials, Quanzhou Normal University, Quanzhou 362000, Fujian (China); Environmental Engineering and Science Program, 705 Engineering Research Center, University of Cincinnati, Cincinnati, OH 45221-0012 (United States); Han, Changseok [ORISE Post-doctoral Fellow, The U.S. Environmental Protection Agency, ORD, NRMRL, STD, CPB, 26 W. Martin Luther King Jr. Drive, Cincinnati, OH 45268 (United States); Nadagouda, Mallikarjuna N. [The U.S. Environmental Protection Agency, ORD, NRMRL, WSWRD, WQMB, 26 W. Martin Luther King Jr. Drive, Cincinnati, OH 45268 (United States); Dionysiou, Dionysios D., E-mail: dionysios.d.dionysiou@uc.edu [Environmental Engineering and Science Program, 705 Engineering Research Center, University of Cincinnati, Cincinnati, OH 45221-0012 (United States); Nireas-International Water Research Centre, School of Engineering, University of Cyprus, PO Box 20537, 1678, Nicosia (Cyprus)

    2016-08-05

    Highlights: • An innovative adsorbent was successfully synthesized to remove humic acid. • The adsorbent possessed high adsorption capacity for humic acid. • The adsorption capacity remarkably increased after an acid modification. • The adsorption capacity was proportional to the amount of ZnO coated on zeolite. • Electrostatic interactions are a major factor at the first stage of the process. - Abstract: Zinc oxide (ZnO)-coated zeolite adsorbents were developed by both nitric acid modification and Zn(NO{sub 3}){sub 2}·6H{sub 2}O functionalization of zeolite 4A. The developed adsorbents were used for the removal of humic acid (HA) from aqueous solutions. The synthesized materials were characterized by porosimetry analysis, scanning electron microscopy, X-Ray diffraction analysis, and high resolution transmission electron microscopy. The maximum adsorption capacity of the adsorbents at 21 ± 1 °C was about 60 mgC g{sup −1}. The results showed that the positive charge density of ZnO-coated zeolite adsorbents was proportional to the amount of ZnO coated on zeolite and thus, ZnO-coated zeolite adsorbents exhibited a greater affinity for negatively charged ions. Furthermore, the adsorption capacity of ZnO-coated zeolite adsorbents increased markedly after acid modification. Adsorption experiments demonstrated ZnO-coated zeolite adsorbents possessed high adsorption capacity to remove HA from aqueous solutions mainly due to strong electrostatic interactions between negative functional groups of HA and the positive charges of ZnO-coated zeolite adsorbents.

  18. An innovative zinc oxide-coated zeolite adsorbent for removal of humic acid

    International Nuclear Information System (INIS)

    Wang, Lingling; Han, Changseok; Nadagouda, Mallikarjuna N.; Dionysiou, Dionysios D.

    2016-01-01

    Highlights: • An innovative adsorbent was successfully synthesized to remove humic acid. • The adsorbent possessed high adsorption capacity for humic acid. • The adsorption capacity remarkably increased after an acid modification. • The adsorption capacity was proportional to the amount of ZnO coated on zeolite. • Electrostatic interactions are a major factor at the first stage of the process. - Abstract: Zinc oxide (ZnO)-coated zeolite adsorbents were developed by both nitric acid modification and Zn(NO_3)_2·6H_2O functionalization of zeolite 4A. The developed adsorbents were used for the removal of humic acid (HA) from aqueous solutions. The synthesized materials were characterized by porosimetry analysis, scanning electron microscopy, X-Ray diffraction analysis, and high resolution transmission electron microscopy. The maximum adsorption capacity of the adsorbents at 21 ± 1 °C was about 60 mgC g"−"1. The results showed that the positive charge density of ZnO-coated zeolite adsorbents was proportional to the amount of ZnO coated on zeolite and thus, ZnO-coated zeolite adsorbents exhibited a greater affinity for negatively charged ions. Furthermore, the adsorption capacity of ZnO-coated zeolite adsorbents increased markedly after acid modification. Adsorption experiments demonstrated ZnO-coated zeolite adsorbents possessed high adsorption capacity to remove HA from aqueous solutions mainly due to strong electrostatic interactions between negative functional groups of HA and the positive charges of ZnO-coated zeolite adsorbents.

  19. Hydrogenation of Anthracene in Supercritical Carbon Dioxide Solvent Using Ni Supported on Hβ-Zeolite Catalyst

    Directory of Open Access Journals (Sweden)

    Ashraf Aly Hassan

    2012-01-01

    Full Text Available Catalytic hydrogenation of anthracene was studied over Ni supported on Hβ-zeolite catalyst under supercritical carbon dioxide (sc-CO2 solvent. Hydrogenation of anthracene in sc-CO2 yielded 100% conversion at 100 °C, which is attributed to the reduced mass transfer limitations, and increased solubility of H2 and substrate in the reaction medium. The total pressure of 7 MPa was found to be optimum for high selectivity of octahydroanthracene (OHA. The conversion and selectivity for OHA increased with an increase in H2 partial pressure, which is attributed to higher concentration of hydrogen atoms at higher H2 pressures. The selectivity reduced the pressure below 7 MPa because of enhanced desorption of the tetrahydro-molecules and intermediates from Ni active sites, due to higher solubility of the surface species in sc-CO2. The selectivity of OHA increased with the increase in catalyst weight and reaction time. The rate of hydrogenation of anthracene was compared with that found for napthalene and phenanthrene. The use of acetonitrile as co-solvent or expanded liquid with CO2 decreased the catalytic activity.

  20. Evaluation of the rheological behavior of asphaltic binder modified with zeolite material

    Energy Technology Data Exchange (ETDEWEB)

    Silveira, E.M. da; Sant' ana, Hosiberto B.; Soares, Sandra A.; Soares, Jorge B. [Federal University of Ceara, Fortaleza, CE (Brazil)

    2008-07-01

    Several new processes have been developed to reduce mixing and compaction temperatures of hot mix asphalt without sacrificing the quality of the resulting pavement. One of these processes utilizes the zeolite, a crystalline hydrated aluminum silicate. A laboratory study was conducted to determine the applicability of zeolite to improve the rheological and chemical behavior of an asphaltic binder. The synthetic asphaltic binder was produced with different zeolite contents (0,1; 0.3; and 0.5% w/w) by wet process. The rheological and chemical behavior was verified by Dynamic Shear Rheometer and Infrared Spectroscopy, respectively. The zeolite's chemical composition and morphology was studied by Dispersive X-ray Spectroscopy (EDX). Additionally, the scanning electron microscope (SEM) was utilized to establish the zeolite elemental composition. The results showed that investigated zeolite was classified as a sodium aluminum silicate and it was able to modify the rheological properties of the neat asphalt binder. The G*/sin{delta} parameter was affected by the zeolite presence, indicating better performance for the binders with zeolite. The results show that synthetic binders can partly replicate the rheological properties of conventional AB. Comparable complex modulus values was obtained. No significant difference was found in viscoelastic response, given by the phase angles as a function of both temperature and frequency. (author)

  1. Metal doped green zeolites for water treatment a sustainable remediation model

    International Nuclear Information System (INIS)

    Tabassum, N.; Rafique, U.

    2016-01-01

    The synthesis of zeolites from refused materials presents a greener model for environmental remediation. The present study offers a novel procedure to synthesize not only the basic framework but also Vanadium modified polymeric zeolites. The spent polythene bags, lunch boxes, and packaging are used as raw material for synthesis of zeolites. Characterization through EDX showed incorporation of vanadium is more than 35%, exhibiting FTIR frequencies in the range 601-995cm-1. Thermogravimetric (TG) analysis revealed a stabilizing effect of zeolites on addition of dopant upto 320 degree C as determined by higher residue percentage (> 98%). Vanadium doped synthesized zeolites (MP1, MP2, MP3) were applied in batch adsorption experiments for in-situ (synthetic metal salt solution) and ex-situ (industrial effluents) removal of metals (Pb, Cr, and Cd). Adsorption results indicated the successful metal removal of more than 90% in the sequence Pb > Cd > Cr. The sequence follows, higher is the ionic radius of the metal cation, more is the adsorption on zeolites. Application of adsorption isotherms demonstrated fitness of Freundlich and Temkin models, whereas pseudo first order kinetics depicts metal removal. The study concludes that synthesized zeolites are suitable candidates with improvised green economy for industrial sector to treat effectively industrial discharges. (author)

  2. Effect of cation nature of zeolite on carbon replicas and their electrochemical capacitance

    International Nuclear Information System (INIS)

    Zhou, Jin; Li, Wen; Zhang, Zhongshen; Wu, Xiaozhong; Xing, Wei; Zhuo, Shuping

    2013-01-01

    Graphical abstract: Cation nature of zeolite influences the porosity, surface chemical properties of carbon replicas of zeolite, resulting in different electrochemical capacitance. Highlights: ► The porosity of carbon replica strongly depends on zeolite's effective pore size. ► The surface chemical properties influence by the cation nature of zeolite. ► The N-doping introduces large pseudo-capacitance. ► The HYC800 carbon showed a high capacitance of up to 312 F g −1 in 1 M H 2 SO 4 . ► The prepared carbons show good durability of galvanostatic cycle. -- Abstract: N-doped carbon replicas of zeolite Y are prepared, and the effect of cation nature of zeolite (H + or Na + ) on the carbon replicas is studied. The morphology, structure and surface properties of the carbon materials are investigated by scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), N 2 adsorption, X-ray photoelectron spectroscopy (XPS) and Fourier transform infrared spectroscopy (FT-IR). The pore regularity, pore parameter and surface chemical properties of the carbons may strongly depend on the cation nature of the zeolite Y. The carbon replicas of zeolite HY (H-form of zeolite Y) possesses higher pore regularity and much larger surface area than those of zeolite NaY (Na-form of zeolite Y), while the latter carbons seem to possess higher carbonization degrees. Electrochemical measurements show a large faradaic capacitance related to the N- or O-containing groups for the prepared carbons. Owing to the large specific surface area, high pore regularity and heteroatom-doping, the HYC800 sample derived from zeolite HY presents very high gravimetric capacitance, up to 312.4 F g −1 in H 2 SO 4 electrolyte, and this carbon can operate at 1.2 V with good retention ratio in the range of 0.25 to 10 A g −1

  3. Synthesis of zeolite from coal fly ashes with different silica-alumina composition

    Energy Technology Data Exchange (ETDEWEB)

    Miki Inada; Yukari Eguchi; Naoya Enomoto; Junichi Hojo [Kyushu University, Fukuoka (Japan). Department of Chemistry and Biochemistry, Graduate School of Engineering

    2005-02-01

    Coal fly ashes can be converted into zeolites by hydrothermal alkaline treatment. This study focuses on the effect of Si/Al molar ratio of the fly ash source on the type of formed zeolite, which also is affected by the alkaline condition. The fly ashes were mixed with an aqueous NaOH solution and hydrothermally treated at about 100{degree}C. Zeolite Na-P1 and/or hydroxy-sodalite appeared after the treatment. Zeolite Na-P1 predominantly formed from silica-rich fly ash at a low-NaOH concentration. The cation exchange capacity of the product with a large content of zeolite Na-P1 reached a value of 300 meq/100 g. The type of the product was controlled by addition of aerosil silica or alumina. It was found that silica addition effectively enhances the formation of zeolite Na-P1, even at a high-NaOH concentration. These results were discussed on the basis of a formation mechanism of zeolite from coal fly ash through dissolution-precipitation process. 10 refs., 6 figs., 1 tab.

  4. Fire Performance of Plywood Treated with Ammonium Polyphosphate and 4A Zeolite

    Directory of Open Access Journals (Sweden)

    Mingzhi Wang

    2014-07-01

    Full Text Available Plywood samples treated with ammonium polyphosphate (APP and 4A zeolite were prepared to investigate the effect of zeolite on wood’s burning behavior using a cone calorimeter under a heat flux of 35 kW/m2. Results showed that APP decreased the heat release rate (HRR, total heat release (THR, and mass loss rate (MLR of treated plywood. However, APP significantly increased the total smoke release (TSR and carbon monoxide (CO yield. The addition of 4A zeolite reduced the HRR, peak HRR, and THR of the plywood treated with only APP. The second HRR peak in a typical plywood curve diminished with the addition of as little as 2% 4A zeolite. The average specific extinction area (ASEA and CO yield decreased significantly with the presence of zeolite in the APP. The ignition time did not change significantly and the TSR increased when zeolite was present. Thus, a suitable amount of 4A zeolite works synergistically with APP in promoting flame retardancy in flame retardant plywood.

  5. Sorption of 60 Co in natural zeolite (clinoptilolite)

    International Nuclear Information System (INIS)

    Hernandez B, E.

    1996-01-01

    A Mexican zeolite (clinoptilolite) from Taxco, Guerrero, was partially stabilized with sodium cations. Radioactive Cobalt ( 60 Co) was used to study the Co 2+ sorption in the stabilized zeolite (Na + ). It was found that sorption in general does not favour the diffusion of cobalt between framework, it explains because of it is a natural zeolite and its composition heterogeneous decrease its exchange capacity by the generated competence to the existence other type of exchange ions. The cobalt retention reached the highest level, around 0.408 m eq Co 2+ /g in the Na-Clinoptilolite. The crystallinity of the aluminosilicates was maintained during experiments, it was verified by XRD patterns. (Author)

  6. The Use of Zeolit and Activated Carbon on Packing System of Corydoras aenus

    Directory of Open Access Journals (Sweden)

    E. Supriyono

    2007-07-01

    Full Text Available Problem frequently found by Indonesian exporter in sending ornamental fish including Corydoras aenus to overseas is the low survival rate that caused by decrease in water quality during transportation.  Suitable and efficient packing technology is very needed to send live fish for long time transportation.  Two third of packing plastic volume was filled by oxygen, and Corydoras aenus 20 fish/pack.  Packing plastic was placed into styrofoam and ice was added to maintain at low temperature.  Zeolit and activated carbon was cover up by cloth and then placed into the pack.  Dosage treatment of zeolit and activated carbon was 20 gram zeolit, 15 gram zeolit and 5 gram activated carbon, 10 gram zeolit and 10 gram activated carbon, 5 gram zeolit and 15 gram activated carbon, 20 gram activated carbon, and no added zeolit and no activated carbon as control.  Fish condition was observed every 6 hours, while water quality measurement was performed every 24 hours for 120 hours.  The results of study showed that adding 20 gram zeolit without activated carbon in closed packing system of Corydoras aenus in 20oC could maintained in lower concentration of total nitrogen ammonia and unionized ammonia (NH3, reached of 7.83±0.13 mg/l and 0.046±0.003 mg/l, respectively.  The level of total nitrogen ammonia and unionized ammonia were relatively lower compared to mix of zeolit and activated carbon, and only activated carbon.  Survival rate of fish by this treatment was 100%, higher than other treatment (85-95%. Keywords: zeolit, activated carbon, packing, Corydoras   ABSTRAK Permasalahan yang sering dihadapi oleh para eksportir Indonesia dalam pengiriman ikan hias termasuk Corydoras aenus ke luar negeri adalah rendahnya survival rate diantaranya disebabkan oleh kualitas air yang memburuk selama pengangkutan. Teknologi pengepakan yang tepat dan efisien sangat dibutuhkan dalam rangka pengiriman ikan hidup untuk tempat tujuan yang membutuhkan waktu lama

  7. Zeolit Sintetis Terfungsionalisasi 3-(Trimetoksisilil-1-Propantiol sebagai Adsorben Kation Cu(II dan Biru Metilena

    Directory of Open Access Journals (Sweden)

    Sri Sugiarti

    2017-05-01

    Full Text Available The more commonly used method for making synthetic zeolite from kaolin is hydrothermal method. This research tested a sol-gel method in processing synthetic zeolit  using kaolin as the basic ingrediant. The synthetic  zeolite  derived from the sol-gel method was then characterized using X-ray Difractometer and Scanning Electron Microscope, which found resulting products zeolite-A, zeolite Y and sodalite. The adsorption ability of the synthetic zeolites was tested using Cu(II and methylene blue.  Functionalization of the synthetic zeolites by 3-(trimetoksisilil-1-propantiol was  done to increase adsorption capacity. Zeolite A modified by 3-(trimetoksisilil-1-propantiol  had the greater capacity to adsorb methylene blue at 30.11 mg/g. The adsorption isotherms of all the synthetic zeolites approached the Langmuir form. The adsorption energy off all synthetic zeolites approached the chemical adsorption.DOI: http://dx.doi.org/10.15408/jkv.v0i0.5144

  8. The Separation Of The Uranium On The Liquid Radioactive Wastes By Using Zeolites

    International Nuclear Information System (INIS)

    Budiyono, ME; Peornomo, Herry; S, Djoko

    2000-01-01

    The experimental investigation on the separation of uranium of liquid radioactive wastes by using zeolite has been carried out. The aims of this investigation was to separate uranium and to determine the solid content of the liquid radioactive waste. This investigation was carried out because zeolite could be used as a good sorption material. The investigation parameters were the number of zeolites, the pH of wastes and the grain size of zeolites. The number of zeolites was varied from 10-100 g, the waste pH was varied from 1-12 and the grain size of zeolites was varied from 20/40-100/200 mesh, each parameters to included in the waste. The conclusion that could be drawn from this investigation were that the best result of the 80 g zeolites used, pH was 9, and the grain size of zeolites was 60/80 mesh, the solid content was 119,46 g/l and efficiency of separation was 81,74 %. As a rule, the solid content in the evaporator process should be about 200-300 g/l

  9. Penggunaan Zeolit Sebagai Media Penyaring Pada Pengolahan Air LimbahDomestik

    Directory of Open Access Journals (Sweden)

    Yanto Yanto

    2011-02-01

    Full Text Available Sand filter is frequentlyused to treat contaminated water. Channel filter system is a modification of sand filter where the channel is shaped thus the land requirement could be minimized, water is flowed horizontallyfrom intial tank to finaltank through sand filter. Employing the channel filter to treat domestic wastewateris capable of reducing E. Coli up to 98.14%, increasing DO up to 27% and decreasing BOD5 up to 27%. Unfortunately, the final content of E.Coli after treatment process completed is still unacceptable for drinking water. Several options are available to improve the performance of the channel filter system. One of the promising alternativesis modifying the filter medium. Zeolite is natural material that has been utilized to improvewater quality based on several parameters such as Fe, Mn, organic materials, CO and others. Application of zeolite to diminish E. Coli is a challenge. This paper will investigate the effectiveness of zeolite to lower E. Coli contained in domestic wastewater . Zeolite was added to sand filter where thefraction of zeolite is about 5%. Two kind of zeolite-sand combination was implemented that is arranged and mixed zeolite-sand. Wastewater containing E.Coli was then put in the initial tank. Through the hole createdin the tank, wastewater then flowed passing through the combined zeolite-sand filter and accumulated in the final tank. Both E. Coli from initial and final tank was measured to compute treatment efficiency. The result showsE. Coli decreases up to99.99%, BOD5and DO decrease more than 71% and 66% respectively. It can be concluded that 5% addition ofzeolite is able to improve treatment efficiency ofsand filter.

  10. Natural zeolites: characteristic, properties and uses

    International Nuclear Information System (INIS)

    Bosch, P.; Bulbulian, S.; Olguin, M. T.

    2011-01-01

    The zeolites are a crystalline aluminium silicates family of volcanic origin. It characterizes them a porous structure, nano metric, regular and homogeneous. Therefore, they turn out to be excellent molecular sieves besides exchangers of ions. This last property it has been extremely exploited, in order to retain the radioactive ions of the contaminated waters in the accident of Three Mile Island (USA), of Chernobyl (Russia) and Fukushima Daiichi (Japan). Nevertheless, the use of the zeolites goes but there ... these they can work as much as nutritional supplement for chickens and pigs, as well as for to retain odors or to separate gases. The construction industry has welcomed this mineral, when either using it as quarry or additive in the called pozzolanic cements. In this book the authors explain the zeolites formation in the nature, their structure and the main uses of these minerals that some authors have baptized as the magic rocks. (Author)

  11. Hierarchical ZSM-5 zeolite:Synthesis and catalytic applications%多级孔道ZSM-5分子筛的合成及其催化应用

    Institute of Scientific and Technical Information of China (English)

    崔生航; 张君涛; 申志兵

    2015-01-01

    Due to high shape selectivity of microporous zeolite and the excellent mass transport of the mesoporous material,the hierarchical ZSM-5 zeolite has potential applications in catalytic field. The synthesis methods and application progress of hierarchical ZSM-5 zeolite in recent years are reviewed in this paper. Various approaches of hierarchical ZSM-5 zeolite synthesis were introduced,including post-treatment method,hard templating method and soft templating method. In addition,the catalytic applications of the as-synthesized zeolites were discussed. It was demonstrated that the reaction conversion and selectivity of target products were improved due to the excellent mass transport and appropriate acidity of the hierarchical ZSM-5 zeolite. This paper also forecasted the development of the hierarchical ZSM-5 zeolite in chemical industry. It was pointed out that the development of facile, economic and green routes towards the synthesis of hierarchical ZSM-5 zeolite would be a challenge in modern industrial catalysis. Research should focus on the mechanism of the mesopore formation,the development of the hierarchical ZSM-5 monolith zeolite as well as the supported hierarchical ZSM-5 zeolites.%多级孔道ZSM-5分子筛具有微孔沸石分子筛良好的择形催化性能和介孔材料优异的传质扩散性能,在催化领域显示出良好的应用前景.本文综述了近年来多级孔道 ZSM-5 分子筛的研究进展,重点介绍了多级孔道ZSM-5 分子筛的不同合成方法,包括后处理法、硬模板法和软模板法等,同时介绍了不同方法得到的多级孔道ZSM-5分子筛在催化反应中的应用,分析表明多级孔道ZSM-5分子筛以其良好的扩散性能和适宜的酸性提高了反应转化率和目标产物选择性.最后对多级孔道ZSM-5分子筛的发展方向进行了展望,指出研发简单、经济和环保的新合成路线是多级孔道ZSM-5分子筛发展中的重大挑战,深入研究多级孔道分子筛

  12. Adsorption methods for hydrogen isotope storage on zeolitic sieves

    International Nuclear Information System (INIS)

    Cristescu, Ioana; Cristescu, Ion; Vasut, F.; Brad, S.; Lazar, A.

    2001-01-01

    For hydrogen isotope separation, adsorption molecular sieves and active carbon were used. Adsorption process proceeds at liquid nitrogen and liquid hydrogen temperatures. Commercial zeolites have the same proprieties with natural zeolites, but they have a regular pore structure. They also have affinity for molecules of different size with defined shapes. Experimental results obtained at liquid nitrogen temperature (77.4 K) and liquid hydrogen revealed the efficient behaviour of the active carbon and zeolitic sieves for hydrogen isotopes temporary storage. We study adsorption of the synthetic zeolites in a wide range of temperatures and pressures and we used the molecular sieves 4A, 5A and active carbon. The 4A and 5A zeolites have a tridimensional structure with 11.4 A diameter. When the hydration water is eliminated, the material keeps a porous structure. The porous volume represents 45% from the zeolite mass for 4A and 5A sieves. The activation temperature of the zeolite and the carbon is very important for obtaining a high adsorption capacity. If the temperature used for activation is low, the structural water will be not eliminated and the adsorption capacity will be low. The excessive temperature will destroy the porous structure. The adsorption capacity for the hydrogen isotopes was calculated with the relation: A = V ads /m (cm 3 /g). The adsorption capacity and efficiency for the adsorbent materials, are given. Physical adsorption process of the hydrogen isotopes was carried out at liquid nitrogen temperature. The flux gas used in the adsorption system is composed of dry deuterium and protium. This mixture is cooled in liquid nitrogen and then is passed to the adsorbent getter at the same temperature (77.4 K). The gas flux in the adsorbent getter is 5 and 72 l/h (which correspond to 0.008 and 0.134 discharge velocity, respectively). (authors)

  13. Adsorption of aqueous Zn(II) species on synthetic zeolites

    International Nuclear Information System (INIS)

    Badillo-Almaraz, Veronica; Trocellier, Patrick; Davila-Rangel, Ignacio

    2003-01-01

    To supply a good quality drinkable water tends to become a strategic task in both developed and under development countries in the world due to the number of potential contamination sources. One of the major problems is derived from the presence of heavy toxic metals like zinc or lead resulting from industrial activities. Zeolites are known as very efficient mineral substrates for fixing aqueous ionic species through their wide range of channels present in the crystalline structure and due to their strong surface reactivity. MicroPIXE coupled with microRBS (3.05 MeV 4 He + ions) have been used to quantify the incorporation of zinc within two commercial zeolites containing alkali elements (zeolite X and clinoptilolite) in the concentration range of: 0.0002-0.05 M at neutral pH. At the beginning of the interaction between zeolite and Zn(II) solution, the adsorption process exhibits a direct proportionality between the content of zinc fixed on the mineral substrate and the aqueous concentration up to 0.01 M. Beyond this point a saturation effect seems to occur, indicating the strong decrease of available adsorption sites. Sodium or potassium ions are probably exchanged with Zn(II) ions during this process. The compared behaviour of the two zeolites is then discussed in terms of kinetic effects based on ionic radius values. A co-adsorption test carried on with a 50-50% Zn(II) 0.001 M-Pb(II) 0.001 M solution shows that lead does not occupy the same sites as zinc because the content of zinc fixed on the zeolite sample exactly corresponds to the result obtained with a pure 0.001 M Zn(II) solution. All these data clearly showed that zeolite surface reactivity is greatly influenced by the mineral cage-like structure and particularly the presence of pockets, spaces and channels

  14. Vitrification of copper flotation waste

    Energy Technology Data Exchange (ETDEWEB)

    Karamanov, Alexander [Institute of Physical Chemistry, Bulgarian Academy of Science, G. Bonchev Str. Block 11, 1113 Sofia (Bulgaria)]. E-mail: karama@ing.univaq.it; Aloisi, Mirko [Department of Chemistry, Chemical Engineering and Materials, University of L' Aquila, 67040 Monteluco di Roio, L' Aquila (Italy); Pelino, Mario [Department of Chemistry, Chemical Engineering and Materials, University of L' Aquila, 67040 Monteluco di Roio, L' Aquila (Italy)

    2007-02-09

    The vitrification of an hazardous iron-rich waste (W), arising from slag flotation of copper production, was studied. Two glasses, containing 30 wt% W were melted for 30 min at 1400 deg. 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.

  15. Vitrification of copper flotation waste.

    Science.gov (United States)

    Karamanov, Alexander; Aloisi, Mirko; Pelino, Mario

    2007-02-09

    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.

  16. Vitrification of copper flotation waste

    International Nuclear Information System (INIS)

    Karamanov, Alexander; Aloisi, Mirko; Pelino, Mario

    2007-01-01

    The vitrification of an hazardous iron-rich waste (W), arising from slag flotation of copper production, was studied. Two glasses, containing 30 wt% W were melted for 30 min at 1400 deg. 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

  17. Validation data supporting the characterization of novel copper complexes as anticancer agents

    Directory of Open Access Journals (Sweden)

    Ceyda Acilan

    2016-12-01

    Full Text Available Three copper(II complexes, Cu(Sal-Gly(phen, Cu(Sal-Glypheamine, Cu(Sal-Glyphepoxy were synthesized and characterized for their anticancer properties and mechanism of action (Acilan et al., in press [1]. Here, we provide supporting data on colon cancer cell lines complementing our previous findings in cervix cells. This paper also contains a data table for the fold changes and p-values of all genes analyzed in this study via a custom RT-qPCR array. All compounds induced DNA damage (based on 8-oxo-guanidine, ɣH2AX staining in cells and apoptosis (based on elevated DNA condensation/fragmentation, Annexin V staining, caspase 3/7 activity and mitochondrial membrane depolarization in HCT-116 colon cancer cells. The increase in oxidative stress was also further confirmed in these cells. Further interpretation of the data presented here can be found in the article entitled “Synthesis, biological characterization and evaluation of molecular mechanisms of novel copper complexes as anticancer agents” (Acilan et al., in press [1].

  18. Epitaxially Grown Layered MFI–Bulk MFI Hybrid Zeolitic Materials

    KAUST Repository

    Kim, Wun-gwi

    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 μm), 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 N2 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 CO2 and good CO2/CH4 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 CO2 and CH4 gas permeabilities of the interpenetrated layer at the BMLM/polyimide interface. © 2012 American Chemical Society.

  19. Hot isostatic pressing of glass-zeolite composites

    International Nuclear Information System (INIS)

    Hash, M.C.; Pereira, C.; Lewis, M.A.

    1996-01-01

    Glass-zeolite waste forms are being developed for immobilizing the chloride waste salt generated from the electrometallurgical treatment of spent fuel. Glass-zeolite composites with high densities were made using hot isostatic pressing (HIP) techniques. Processing parameters were investigated to yield desirable structural ceramic properties such as mechanical, chemical, and thermal stability. Limits for these parameters were determined by differential thermal and thermogravimetric analysis. The resulting ceramic properties such as bulk density, open or apparent porosity, and leach resistance were determined. In addition, phase equilibria and particle-size distribution were observed by optical light and electron microscopy. Pre-HIP processing techniques were also studied to ensure intimate mixing of the glass and zeolite powders. Particle size distributions resulting from dry blending procedure are appropriate for needed flow and packing characteristics

  20. Synthesis of ceramic hollow fiber supported zeolitic imidazolate framework-8 (ZIF-8) membranes with high hydrogen permeability

    KAUST Repository

    Pan, Yichang; Wang, Bo; Lai, Zhiping

    2012-01-01

    Purification and recovery of hydrogen from hydrocarbons in refinery streams in the petrochemical industry is an emerging research field in the study of membrane gas separation. Hollow fiber membrane modules can be easily implemented into separation processes at the industrial scale. In this report, hollow yttria-stabilized zirconia (YSZ) fiber-supported zeolitic imidazole framework-8 (ZIF-8) membranes were successfully prepared using a mild and environmentally friendly seeded growth method. Our single-component permeation studies demonstrated that the membrane had a very high hydrogen permeance (~15×10 -7mol/m 2sPa) and an ideal selectivity of H 2/C 3H 8 of more than 1000 at room temperature. This high membrane permeability and selectivity caused serious concentration polarization in the separation of H 2/C 3H 8 mixtures, which led to almost 50% drop in both the H 2 permeance and the separation factor. Enhanced mixing on the feed side could reduce the effect of the concentration polarization. Our experimental data also indicated that the membranes had excellent reproducibility and long-term stability, indicating that the hollow fiber-supported ZIF-8 membranes developed in this study have great potential in industry-scale separation of hydrogen. © 2012 Elsevier B.V.

  1. Synthesis of ceramic hollow fiber supported zeolitic imidazolate framework-8 (ZIF-8) membranes with high hydrogen permeability

    KAUST Repository

    Pan, Yichang

    2012-12-01

    Purification and recovery of hydrogen from hydrocarbons in refinery streams in the petrochemical industry is an emerging research field in the study of membrane gas separation. Hollow fiber membrane modules can be easily implemented into separation processes at the industrial scale. In this report, hollow yttria-stabilized zirconia (YSZ) fiber-supported zeolitic imidazole framework-8 (ZIF-8) membranes were successfully prepared using a mild and environmentally friendly seeded growth method. Our single-component permeation studies demonstrated that the membrane had a very high hydrogen permeance (~15×10 -7mol/m 2sPa) and an ideal selectivity of H 2/C 3H 8 of more than 1000 at room temperature. This high membrane permeability and selectivity caused serious concentration polarization in the separation of H 2/C 3H 8 mixtures, which led to almost 50% drop in both the H 2 permeance and the separation factor. Enhanced mixing on the feed side could reduce the effect of the concentration polarization. Our experimental data also indicated that the membranes had excellent reproducibility and long-term stability, indicating that the hollow fiber-supported ZIF-8 membranes developed in this study have great potential in industry-scale separation of hydrogen. © 2012 Elsevier B.V.

  2. Effect of Annealing Temperature on Broad Luminescence of Silver-Exchanged Zeolites Y and A

    Science.gov (United States)

    Gui, Sa Chu Rong; Lin, H.; Bao, W.; Wang, W.

    2018-05-01

    The annealing temperature dependence of luminescence properties of silver (Ag)-exchanged zeolites Y and A was studied. It was found that the absorbance and excitation/emission bands are strongly affected by the thermal treatments. With increase in annealing temperature, the absorbance of Ag in zeolite Y increases at first and then decreases. However, the position of the excitation/emission band in zeolite Y was found to be insensitive to the annealing temperature. In contrast, the excitation/emission bands in zeolite A are particularly sensitive to the annealing temperature. The difference of such temperature dependence in zeolites Y and A may be due to the different microporous structure of the two minerals. Moreover, the fact that this dependence is not observed in Ag-exchanged zeolite Y is likely to be due to the difficulty in dehydration of zeolite Y in air or due to the weak Ag+-Ag+ interaction in zeolite Y.

  3. Epitaxially Grown Layered MFI–Bulk MFI Hybrid Zeolitic Materials

    KAUST Repository

    Kim, Wun-gwi; Zhang, Xueyi; Lee, Jong Suk; Tsapatsis, Michael; Nair, Sankar

    2012-01-01

    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

  4. FY 1998 results of the regional consortium R and D project/the venture promotion type regional consortium R and D (small-/medium-size venture creation type). 2nd year. Development of hazardous materials removal technology using high-functional zeolite; 1998 nendo kokinoka zeolite wo mochiita yugai busshitsu jokyo gijutsu no kaihatsu seika hokokusho. 2

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2000-03-01

    The R and D were carried out aiming at developing a device which removes/recovers freon substitutes and organic solvents discharged from semiconductor/pharmaceutical plans, using zeolite excellent in adsorption performance. In the R and D of high-functional zeolite, the design of materials is conducted by computer simulation, and effectiveness of the simulation was shown. In the development of zeolite honeycombs, the following were conducted: installation of honeycomb-form device, study of formation conditions, and fabrication of samples for adsorption/desorption tests. Moreover, the R and D were made on heater-monolithic zeolite, surface treatment of zeolite honeycomb, catalyst support, analysis, adsorption/desorption evaluation, micro-porous material cross-linking among clay layers, etc. As to the adsorption unit, the shape was so studied/designed that the gas containing NMP can efficiently keep in touch with zeolite honeycomb. Concerning the design of switching removal/recovery device, conducted were the design of a system which can be controlled at low cost, the development of adsorption/desorption operated software, etc. (NEDO)

  5. Modifikasi Zeolit Dengan Tembaga (Cu) Dan Uji Sifat Katalitiknya Pada Reaksi Esterifikasi

    OpenAIRE

    Arjek, Orien Claudia Handayani; Fatimah, Is

    2017-01-01

    Zeolite modification with Cu has been conducted. Material modification is done by impregnating Cu through a zeolite powder reflux process with CuSO4.5H2O solution so that theoretical Cu concentration is 5% followed by oxidation and reduction of solids. Material characterization was performed by x-ray diffraction analysis (XRD), Fourier Transform Infra-Red (FTIR) and acidity testing of Cu/Zeolite catalyst.The results showed that the crystallinity level of Cu/Zeolite did not change significantl...

  6. Effect of zeolite (clinoptilolite) as feed additive in Tunisian broilers on the total flora, meat texture and the production of omega 3 polyunsaturated fatty acid

    Science.gov (United States)

    2012-01-01

    Background Increasing consumer demand for healthier food products has led to the development of governmental policies regarding health claims in many developed countries. In this context, contamination of poultry by food-borne pathogens is considered one of the major problems facing the progress of the poultry industry in Tunisia. Result Zeolite (Clinoptilolites) was added to chicken feed at concentrations 0,5% or 1% and was evaluated for its effectiveness to reduce total flora in chickens and its effects on performance of the production. The broilers were given free and continuous access to a nutritionally non-limiting diet (in meal form)that was either a basal diet or a' zeolite diet' (the basal diet supplemented with clinoptilolite at a level of 0,5% or 1%). It was found that adding zeolite in the broiler diet significantly (p zeolite treatment had a positive effect on performance production and organoleptic parameters that were measured and mainly on the increase level of Omega 3 fatty acid. Conclusion This study showed the significance of using zeolite, as a feed additive for broilers, as part of a comprehensive program to control total flora at the broiler farm and to increase level of Omega 3 fatty acid on the chicken body. PMID:22394592

  7. Copper supported on nanostructured mesoporous ceria-titania composites as catalysts for sustainable environmental protection: Effect of support composition

    Czech Academy of Sciences Publication Activity Database

    Issa, G. S.; Tsoncheva, T.; Mileva, A.; Dimitrov, M.D.; Kovacheva, D.; Henych, Jiří; Štengl, Václav

    2017-01-01

    Roč. 49, SI D (2017), s. 55-62 ISSN 0324-1130 Grant - others:AV ČR(CZ) BAS-17-13 Program:Bilaterální spolupráce Institutional support: RVO:61388980 Keywords : Mesoporous nanostructured ceria-titania doped with copper * template-assisted hydrothermal synthesis * ethyl acetate oxidation * methanol decomposition Subject RIV: CA - Inorganic Chemistry OBOR OECD: Inorganic and nuclear chemistry Impact factor: 0.238, year: 2016 http://www.bcc.bas.bg/BCC_Volumes/Volume_49_Special_D_2017/BCC2017-49-SE-D-055-062.pdf

  8. Subacute copper-deficiency myelopathy in a patient with occult celiac disease.

    Science.gov (United States)

    Cavallieri, Francesco; Fini, Nicola; Contardi, Sara; Fiorini, Massimo; Corradini, Elena; Valzania, Franco

    2017-07-01

    Acquired copper deficiency represents a rare cause of progressive myelopathy presenting with sensory ataxia and spastic gait. The time interval from neurological symptoms onset to diagnosis of myelopathy ranges from 2 months to several years in almost all cases, mimicking the clinical course of subacute combined degeneration due to vitamin B12 deficiency. A 60-year-old man, without any gastrointestinal symptoms, developed over the course of one week rapidly progressive gait imbalance, tingling and numbness in his feet and ascending lower limb weakness. Spine magnetic resonance imaging revealed hyperintensity involving cervical and dorsal posterior columns of spinal cord. Blood analysis revealed undetectable serum copper levels, low serum ceruloplasmin and positive serum Immunoglobulin A anti-tissue transglutaminase. Upper gastrointestinal endoscopy was performed revealing duodenal villous atrophy consistent with a malabsorption pattern. A gluten-free diet in association with intravenous then oral copper supplementation prompted sustained normalization of serum copper levels and progressive clinical improvement. We report a rare case of myelopathy induced by copper deficiency secondary to undiagnosed celiac disease, peculiarly presenting with a subacute onset. This case expands the neurological presentation and clinical course of myelopathy due to acquired copper deficiency. We suggest investigation of copper deficiency in patients presenting with subacute or even acute sensory ataxia and spastic gait. Detection of hypocupremia in patients without a previous history of gastric surgery should lead to diagnostic testing for celiac disease even in the absence of any obvious gastrointestinal symptoms.

  9. Zeolitic catalytic conversion of alcohols to hydrocarbons

    Science.gov (United States)

    Narula, Chaitanya K.; Davison, Brian H.; Keller, Martin

    2018-04-10

    A method for converting an alcohol to a hydrocarbon, the method comprising contacting said alcohol with a metal-loaded zeolite catalyst at a temperature of at least 100.degree. C. and up to 550.degree. C., wherein said alcohol can be produced by a fermentation process, said metal is a positively-charged metal ion, and said metal-loaded zeolite catalyst is catalytically active for converting said alcohol to said hydrocarbon.

  10. Zeolitic catalytic conversion of alochols to hydrocarbons

    Energy Technology Data Exchange (ETDEWEB)

    Narula, Chaitanya K.; Davison, Brian H.; Keller, Martin

    2017-01-03

    A method for converting an alcohol to a hydrocarbon, the method comprising contacting said alcohol with a metal-loaded zeolite catalyst at a temperature of at least 100.degree. C. and up to 550.degree. C., wherein said alcohol can be produced by a fermentation process, said metal is a positively-charged metal ion, and said metal-loaded zeolite catalyst is catalytically active for converting said alcohol to said hydrocarbon.

  11. Molecular interactions of alcohols with zeolite BEA and MOR frameworks.

    Science.gov (United States)

    Stückenschneider, Kai; Merz, Juliane; Schembecker, Gerhard

    2013-12-01

    Zeolites can adsorb small organic molecules such as alcohols from a fermentation broth. Also in the zeolite-catalyzed conversion of alcohols to biofuels, biochemicals, or gasoline, adsorption is the first step. Several studies have investigated the adsorption of alcohols in different zeolites experimentally, but computational investigations in this field have mostly been restricted to zeolite MFI. In this study, the adsorption of C1-C4 alcohols in BEA and MOR was investigated using density functional theory (DFT). Calculated adsorption geometries and the corresponding energies of the designed cluster models were comparable to periodic calculations, and the adsorption energies were in the same range as the corresponding computational and experimental values reported in the literature for zeolite MFI. Thus, BEA and MOR may be good adsorption materials for alcohols in the field of downstream processing and catalysis. Aside from the DFT calculations, adsorption isotherms were determined experimentally in this study from aqueous solutions. For BEA, the adsorption of significant amounts of alcohol from aqueous solution was observed experimentally. In contrast, MOR was loaded with only a very small amount of alcohol. Although differences were found between the affinities obtained from gas-phase DFT calculations and those observed experimentally in aqueous solution, the computational data presented here represent molecular level information on the geometries and energies of C1-C4 alcohols adsorbed in zeolites BEA and MOR. This knowledge should prove very useful in the design of zeolite materials intended for use in adsorption and catalytic processes, as it allows adsorption behavior to be predicted via judiciously designed computational models.

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

    Science.gov (United States)

    Vaičiukynienė, Danutė; Kantautas, Aras; Vaitkevičius, Vitoldas; Jakevičius, Leonas; Rudžionis, Žymantas; Paškevičius, 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. Copyright © 2015 Elsevier B.V. All rights reserved.

  13. Measurement of cation exchange capacity (CEC) on natural zeolite by percolation method

    Science.gov (United States)

    Wiyantoko, Bayu; Rahmah, Nafisa

    2017-12-01

    The cation exchange capacity (CEC)measurement has been carried out in natural zeolite by percolation method. The natural zeolite samples used for cation exchange capacity measurement were activated beforehand with physical activation and chemical activation. The physically activated zeolite was done by calcination process at 600 °C for 4 hours. The natural zeolite was activated chemically by using sodium hydroxide by refluxing process at 60-80 °C for 3 hours. In summary, cation exchange capacity (CEC) determination was performed by percolation, distillation and titration processes. Based on the measurement that has been done, the exchange rate results from physical activated and chemical activated of natural zeolite were 181.90cmol (+)/kg and 901.49cmol (+)/kg respectively.

  14. Beyond Creation of Mesoporosity: The Advantages of Polymer-Based Dual-Function Templates for Fabricating Hierarchical Zeolites

    KAUST Repository

    Tian, Qiwei

    2016-02-05

    Direct synthesis of hierarchical zeolites currently relies on the use of surfactant-based templates to produce mesoporosity by the random stacking of 2D zeolite sheets or the agglomeration of tiny zeolite grains. The benefits of using nonsurfactant polymers as dual-function templates in the fabrication of hierarchical zeolites are demonstrated. First, the minimal intermolecular interactions of nonsurfactant polymers impose little interference on the crystallization of zeolites, favoring the formation of 3D continuous zeolite frameworks with a long-range order. Second, the mutual interpenetration of the polymer and the zeolite networks renders disordered but highly interconnected mesopores in zeolite crystals. These two factors allow for the synthesis of single-crystalline, mesoporous zeolites of varied compositions and framework types. A representative example, hierarchial aluminosilicate (meso-ZSM-5), has been carefully characterized. It has a unique branched fibrous structure, and far outperforms bulk aluminosilicate (ZSM-5) as a catalyst in two model reactions: conversion of methanol to aromatics and catalytic cracking of canola oil. Third, extra functional groups in the polymer template can be utilized to incorporate desired functionalities into hierarchical zeolites. Last and most importantly, polymer-based templates permit heterogeneous nucleation and growth of mesoporous zeolites on existing surfaces, forming a continuous zeolitic layer. In a proof-of-concept experiment, unprecedented core-shell-structured hierarchical zeolites are synthesized by coating mesoporous zeolites on the surfaces of bulk zeolites. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  15. Synthesis of Titania-supported Copper Nanoparticles via Refined Alkoxide Sol-gel Process

    International Nuclear Information System (INIS)

    Wu, Jeffrey C.S.; Tseng, I.-Hsiang; Chang, W.-C.

    2001-01-01

    Nanoparticles of titania and copper-loaded titania were synthesized by a refined sol-gel method using titanium butoxide. Unlike the conventional sol-gel procedure of adding water directly, the esterification of anhydrous butanol and glacial acetic acid provided the hydrolyzing water. In addition, acetic acid also served as a chelating ligand to stabilize the hydrolysis-condensation process and minimize the agglomeration of titania. Following the hydrolysis, Cu/TiO 2 was prepared by adding copper chloride to titania sol. The sol was dried, then calcined at 500 deg. C to remove organics and transformed to anatase titania which was verified by XRD. Cu/TiO 2 was further hydrogen-reduced at 300 deg. C. The recovery of Ti was exceeded by an average of 95% from titanium butoxide. TEM micrographs show that the Cu/TiO 2 particles are near uniform. The average crystallite sizes are 17-20 nm estimated from the peak broadening of XRD spectra. The bandgaps of TiO 2 and reduced Cu/TiO 2 range from 2.70 to 3.15 eV estimated from the diffusive reflective UV-Vis spectra. XPS analysis shows that Cu 2p 3/2 is 933.4 eV indicating primary Cu 2 O form on the TiO 2 supports. The binding energy of Ti does not exhibit chemical shift suggesting negligible interaction of Cu cluster and TiO 2 support

  16. Synthesis of Titania-supported Copper Nanoparticles via Refined Alkoxide Sol-gel Process

    Science.gov (United States)

    Wu, Jeffrey C. S.; Tseng, I.-Hsiang; Chang, Wan-Chen

    2001-06-01

    Nanoparticles of titania and copper-loaded titania were synthesized by a refined sol-gel method using titanium butoxide. Unlike the conventional sol-gel procedure of adding water directly, the esterification of anhydrous butanol and glacial acetic acid provided the hydrolyzing water. In addition, acetic acid also served as a chelating ligand to stabilize the hydrolysis-condensation process and minimize the agglomeration of titania. Following the hydrolysis, Cu/TiO2 was prepared by adding copper chloride to titania sol. The sol was dried, then calcined at 500°C to remove organics and transformed to anatase titania which was verified by XRD. Cu/TiO2 was further hydrogen-reduced at 300°C. The recovery of Ti was exceeded by an average of 95% from titanium butoxide. TEM micrographs show that the Cu/TiO2 particles are near uniform. The average crystallite sizes are 17-20 nm estimated from the peak broadening of XRD spectra. The bandgaps of TiO2 and reduced Cu/TiO2 range from 2.70 to 3.15 eV estimated from the diffusive reflective UV-Vis spectra. XPS analysis shows that Cu 2p3/2 is 933.4 eV indicating primary Cu2O form on the TiO2 supports. The binding energy of Ti does not exhibit chemical shift suggesting negligible interaction of Cu cluster and TiO2 support.

  17. Synthesis of Titania-supported Copper Nanoparticles via Refined Alkoxide Sol-gel Process

    Energy Technology Data Exchange (ETDEWEB)

    Wu, Jeffrey C.S., E-mail: Cswu@ccms.ntu.edu.tw; Tseng, I.-Hsiang; Chang, W.-C. [National Taiwan University, Department of Chemical Engineering (China)

    2001-06-15

    Nanoparticles of titania and copper-loaded titania were synthesized by a refined sol-gel method using titanium butoxide. Unlike the conventional sol-gel procedure of adding water directly, the esterification of anhydrous butanol and glacial acetic acid provided the hydrolyzing water. In addition, acetic acid also served as a chelating ligand to stabilize the hydrolysis-condensation process and minimize the agglomeration of titania. Following the hydrolysis, Cu/TiO{sub 2} was prepared by adding copper chloride to titania sol. The sol was dried, then calcined at 500 deg. C to remove organics and transformed to anatase titania which was verified by XRD. Cu/TiO{sub 2} was further hydrogen-reduced at 300 deg. C. The recovery of Ti was exceeded by an average of 95% from titanium butoxide. TEM micrographs show that the Cu/TiO{sub 2} particles are near uniform. The average crystallite sizes are 17-20 nm estimated from the peak broadening of XRD spectra. The bandgaps of TiO{sub 2} and reduced Cu/TiO{sub 2} range from 2.70 to 3.15 eV estimated from the diffusive reflective UV-Vis spectra. XPS analysis shows that Cu 2p{sub 3/2} is 933.4 eV indicating primary Cu{sub 2}O form on the TiO{sub 2} supports. The binding energy of Ti does not exhibit chemical shift suggesting negligible interaction of Cu cluster and TiO{sub 2} support.

  18. Changing of Sumatra backswamp peat properties by seawater and zeolite application

    Science.gov (United States)

    Sarifuddin; Nasution, Z.; Rauf, A.; Mulyanto, B.

    2018-02-01

    This research attempts to improve the properties of backswamp peatsoil originated from Asahan District, North Sumatra Indonesia by adding sea water and zeolite using factorial randomized block design with volume of sea water as first factor, consisting of without seawater, 500 ml, 1000 ml and 1500 ml and second factor are dosages of zeolite consisting of without zeolite, 100 g, 200 g each 10 kgs of wet peat soil. at green house in faculty of agriculture University of Sumatra Utara (USU) Medan, Indonesia. The result showed that the application of seawater decreased pH, C/N and Cation Exchange Capacity and increased of base saturation of peat soil. Adding of zeolite minerals can buffered the increasing of acidity and Electric Conductivity caused by sea water application. Interaction seawater + zeolite decreased of C/N and increased of percent of base saturation.

  19. Removal of cesium and strontium from low active waste solutions by zeolites

    International Nuclear Information System (INIS)

    Jain, Savita; Ramaswamy, M.; Theyyunni, T.K.

    1994-01-01

    Ion exchange, crystallographic and thermal characteristics of sodium, cesium and strontium forms of locally available synthetic zeolites have been investigated. X-ray and differential thermal analyses have confirmed that the synthetic materials AR1 and 4A belonged to the mordenite and A type families of zeolites respectively. Equilibrium uptake of cesium and strontium ions by sodium forms of zeolite was studied as a function of time, pH and sodium concentration. It was found that the rate of sorption by AR1 was higher than that by 4A. In regard to pH, distribution of nuclides on zeolites was found to pass through maxima at a pH value of around 9. Sodium ion interfered with the sorption of cesium and strontium by zeolites. However, at sodium concentration ≤ 0.01 M, distribution coefficient values for these nuclides were sufficiently high to merit consideration of these zeolites for low level waste treatment. Lab-scale column runs using 5 ml beds of materials showed that the zeolites AR1 and 4A were very effective in removing cesium and strontium nuclides respectively from large volumes (a decontamination factor of 50 for a throughput of 6000 bed volumes) of actual low level waste solutions. Thus, the zeolite system has a potential future for large scale application in the treatment of low level wastes. (author). 6 refs., 5 figs., 6 tabs

  20. ZEOLITE: "THE MAGIC STONE"; MAIN NUTRITIONAL, ENVIRONMENTAL, EXPERIMENTAL AND CLINICAL FIELDS OF APPLICATION.

    Science.gov (United States)

    Laurino, Carmen; Palmieri, Beniamino

    2015-08-01

    zeolites (clinoptilolites) are a family of alluminosilicates and cations clustered to form macro aggregates by small individual cavities. In the medical area they are involved in detoxification mechanisms capturing ions and molecules into their holes. Actually, we classify about 140 types of natural and 150 synthetic zeolites, for specific and selective use. Clinoptilolite is a natural zeolite and it is the most widespread compound in the medical market. this review analyzes the main fields of zeolite utilization. we searched Pubmed/Medline using the terms "zeolite" and "clinoptilolite". in zoothechnology and veterinary medicine zeolite improves the pets' fitness, removes radioactive elements, aflatoxines and poisons. Zeolite displays also antioxidant, whitening, hemostatic and anti-diarrhoic properties, projected in human care. However very scanty clinical studies have been run up to now in immunodeficiency, oncology after chemotherapy and radiotherapy as adjuvants. further clinical investigations are urgently required after this review article publication which updates the state of the art. Copyright AULA MEDICA EDICIONES 2014. Published by AULA MEDICA. All rights reserved.