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Development and evaluation of Mn oxide-coated composite adsorbent for the removal and recovery of heavy metals from coal processing wastewater. Final report, December 1995  

Energy Technology Data Exchange (ETDEWEB)

The overall objective of this research was to evaluate a Mn oxide-coated granular activated carbon (MnGAC) for the removal and recovery of metals from wastewaters. The composite adsorbent was prepared by coating M-n-oxide onto granular activated carbon. Three coating methods (adsorption, precipitation, and dry oxidation) were developed and studied in this research. The adsorbent (MnTOG) prepared by a dry oxidation method had the highest Cu(II) adsorption capacity of the three synthesis methods. In multiple adsorption/regeneration cycle tests, MnTOG had better Cu(II) removal relative to those adsorbents prepared by other methods. MnTOG had the ability to remove Cu(II) and Cd(II) to trace level (< 4 ug/L) in a column process at least through 3000 and 1400 BV, respectively. Cd(II) removal was hindered by the presence of Cu(II). However, Cu(II) removal was only slightly reduced by the presence of Cd(II). Cu(II) adsorption in batch and fixed-bed processes onto MnTOG was successfully modeled with a homogeneous surface diffusion model (HSDM). However, the HSDM could only successfully describe the adsorption of Cd(II) onto MnTOG in the batch process, but not the fixed-bed process. M-n oxide can be deposited on GAC to create a composite adsorbent with an increased Cu(II) or Cd(II) adsorption capacity. Composite adsorbent (MnGAC) has the potential to become an efficient way to remove metals from metal contaminated wastewater.

Fan, Huan Jung; Anderson, P.R.

1995-12-31

2

Modeling colloid deposition on a protein layer adsorbed to iron-oxide-coated sand  

Science.gov (United States)

Our recent study reported that conformation change of granule-associated Bovine Serum Albumin (BSA) may influence the role of the protein controlling colloid deposition in porous media (Flynn et al., 2012). The present study conceptualized the observed phenomena with an ellipsoid morphology model, describing BSA as an ellipsoid taking a side-on or end-on conformation on granular surface, and identified the following processes: (1) at low adsorbed concentrations, BSA exhibited a side-on conformation blocking colloid deposition; (2) at high adsorbed concentrations, BSA adapted to an end-on conformation promoted colloid deposition; and (3) colloid deposition on the BSA layer may progressively generate end-on molecules (sites) by conformation change of side-on BSA, resulting in sustained increasing deposition rates. Generally, the protein layer lowered colloid attenuation by the porous medium, suggesting the overall effect of BSA was inhibitory at the experimental time scale. A mathematical model was developed to interpret the ripening curves. Modeling analysis identified the site generation efficiency of colloid as a control on the ripening rate (declining rate in colloid concentrations), and this efficiency was higher for BSA adsorbed from a more dilute BSA solution.

Yang, X.; Flynn, R.; von der Kammer, F.; Hofmann, T.

2012-11-01

3

Implementation of the adsorbent iron-oxide-coated natural rock (IOCNR) on synthetic As(III) and on real arsenic-bearing sample with filter  

Science.gov (United States)

This study examined the As(III) adsorption efficiency on an iron-oxide based adsorbent, iron-oxide-coated natural rock (IONR), and proposes an in situ two-step mechanism, oxidation of As(III) to As(V) and its subsequent adsorption on IOCNR. In the batch study, within 6 h of contact time and at a dose of 13 g L-1, ?98.5% As(III) (declined to ?0.01 mg L-1) removal was achieved from the water medium, when the initial concentration was 0.6 mg L-1 at room temperature. The As(III) adsorptive capacity of IOCNR was calculated using the Langmuir isotherm 1.647 mg g-1. The effects of various parameters for As(III) adsorption, including contact time, dose, pH, initial As(III) concentrations, the presence of common cations and anions, along with some organic contaminants, were evaluated. Spontaneity and favorable adsorption of As(III) on IOCNR were evidenced from the negative Gibbs free energy changes and dimensionless equilibrium parameter. As(III) removal efficiency of the exhausted and NaOH-regenerated IOCNR decreased in the second-cycle operation. As(III) removal efficiency of IOCNR was comparable to that of the commercially available patented adsorbent LEWATIT FO36. The adsorptive behavior of IOCNR from real arsenic-bearing sample was also evaluated. Finally, small-scale household filter “SHITAL-2013” was designed and the effluent water quality was analyzed.

Maji, Sanjoy Kumar; Kao, Yu-Hsuan; Liao, Pei-Yu; Lin, Yi-Jie; Liu, Chen-Wuing

2013-11-01

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Structure and Properties of Microarc Oxidation Coatings on SiCP/AZ31 Magnesium Matrix Composite  

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Full Text Available The protective ceramic coatings were prepared on SiC particle reinforced magnesium matrix composite by microarc oxidation (MAO surface treatment technique. The surface morphology, cross-sectional microstructure and phase constituent of ceramic coatings were analyzed. And the microhardness profile, thermal shock resistance and electrochemical corrosion behavior of the coatings were measured. The ceramic coating consists of MgO, Mg2SiO4 and a few phases related to the electrolyte elements. Furthermore, a few residual SiC reinforced particles are also remained in the coatings. The maximum hardness of the coating is about HV800, which is at least five times higher than that of the uncoated composite substrate. The coatings do not detach from composite substrate after the coated samples undergo 100 thermal shocks, heating the sample to 500¡?nd then quenching into water, which displays a good thermal shock resistance for the MAO coatings on SiCP/AZ31 composite. In addition, after MAO surface treatment, the corrosion resistance of the SiCP/AZ31 composite is greatly improved.

XUE Wen-Bin,JIN Qian,ZHU Qing-Zhen,MA Yue-Yu

2009-05-01

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Chemical composition of antifriction micro-arc oxide coatings on titanium alloy VT16  

International Nuclear Information System (INIS)

The results of studies on phase, elementary and chemical compositions of coatings, obtained through the method of microarc oxidation on the VT16 titanium alloy, are presented. These coatings provide for a low friction coefficient of contacting surfaces. It is shown, that the titanium roentgenoamorphous dioxide, constituting the coatings composition and modified by molybdenum, aluminium and phosphorous compounds possesses higher plasticity as compared to the crystalline phase and as a dry lubricant it provides for the friction coefficient decrease up to 0.06-0.16

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The influences of microdischarge types and silicate on the morphologies and phase compositions of plasma electrolytic oxidation coatings on Zircaloy-2  

International Nuclear Information System (INIS)

Highlights: ? ZrO2 coatings are grown on Zircaloy-2 by plasma electrolytic oxidation. ? Characteristic solidification structures are formed on the coatings. ? This structure has not been found on the PEO coatings of other valve metals. ? Very low thermal conductivity of zirconia helps the formation of the structure. - Abstract: Plasma electrolytic oxidation coatings were formed in alkaline silicate electrolyte on Zircaloy-2. The evolution of the types of discharges, the microstructures, phase compositions and the corrosion resistance of the coatings were studied by real time imaging, SEM, XRD, and electrochemical tests. Characteristic solidification structures were revealed in the PEO coatings, the formation of the solidification structures is related to the long lasting discharges during the PEO process and the very low thermal conductivity of zirconium oxide. Thermal effect in the coatings and silicate content in the electrolyte affect the phase compositions of the coatings.

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Effect of current density on the structure, composition and corrosion resistance of plasma electrolytic oxidation coatings on Mg–Li alloy  

International Nuclear Information System (INIS)

Highlights: ? The PEO coatings exhibit tunable characteristics by controlling the current density. ? The coating formed at 5 A/dm2 exhibits the highest corrosion resistance. ? Anti-corrosion properties of PEO coatings are related to coating surface composition. - Abstract: The effect of current density on the oxidation process, morphology, composition and anti-corrosion properties of coatings are elucidated. X-ray photoelectron spectroscopy and X-ray diffraction analysis of coatings show that coatings prepared at different current densities are composed of MgO and ?-Mg2SiO4 and ?-Mg2SiO4 phase. The chemical composition of PEO coatings varies from surface to the interior of the oxide coating. The PEO coatings exhibit tunable thickness, composition ratio, and porosity by controlling the current density, which ultimately affects film morphology and anti-corrosion properties. The superior corrosion resistance of coating obtained at 5 A/dm2 is attributed to the compactness of the barrier layer and the highest MgO/Mg2SiO4 ratio.

8

Method and adsorbant composition for 82Rb generation  

International Nuclear Information System (INIS)

The present invention provides a composition comprising 82Sr and an adsorbant selected from tin oxide, hydrated tin oxide, polyantimonic acid, titanium oxide, hydrated titanium oxide, ferric oxide and hydrated ferric oxide, and also provides a low 82Sr breakthrough method of generating 82Rb which comprises eluting such 82Sr charged adsorbant

9

Isothermal composite adsorbent. Part I: Thermal characterisation  

International Nuclear Information System (INIS)

Adsorption and desorption are respectively exo and endothermic phenomena leading to significant temperature changes in adsorption columns. Enhanced efficiency of a sorption process could be obtained under isothermal conditions, either for gas storage, purification or separation applications. The heat transfer within the adsorbent beds can be managed in situ, using thermal energy storage material: a phase change materials (PCM) for example. The thermal behaviour of a mixture of activated carbon and PCM during CO2 adsorption has been studied. The thermal characteristics of the involved materials have been determined and experiments carried out to highlight the positive effect of the PCM to reduce the CO2 adsorption heat effects on an activated carbon bed. Calorimetry was the technique used for all the thermal characterisations. It appears that the heat effects induced by CO2 adsorption are reduced by the presence of the PCM together with the adsorbent. The endothermic effect of fusion balances the heat effect of adsorption and significantly reduces the temperature changes

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REVIEW: USE of COMPOSITE ADSORBENTS in ADSORPTION REFRIGERATION  

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Full Text Available The urbanization across the world has resulted in increased demand for refrigeration and air conditioning. The main disadvantage with the conventional method i.e. vapor compression system is environment pollution. Another problem faced during urbanization is energy crisis. The adsorption refrigeration system is one of the solutions to this problem. The advantages of this system are environment friendly, less noise, use of waste heat or solar energy. But the disadvantage with adsorption system is low coefficient of performance (COP and bulkiness. Researchers across the world are working on this issue to make adsorption system a viable alternative to the compression systems. Since the last two decades considerable work is being done on the use of composite adsorbents to improve the heat and mass transfer performance. This kind of adsorbent is usually obtained by the combination of a chemical adsorbents and physical adsorbents.

Satishchandra V. Joshi

2012-01-01

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[Effects of film thickness on the phase composition and microstructure properties of micro-arc oxidation coating].  

Science.gov (United States)

In this study, we obtained the TiO2 films with different thickness by micro-are oxidation (MAO) on commercially available pure titanium. By altering the duration time, we got the films 5 microm, 10 microm, and 20 microm in thickness, respectively. XRD and SEM were employed to characterize the phase, composition and microstructure of the films. The MAO film, which was about 5 microm thick, was porous and even with the pore size about 1 microm. No other crystalline phase except anatase was detected by XRD. The film, which was 10 microm thick, was similar to the former. The pores were well separated and homogeneously distributed over the surface. The XRD pattern indicated that the film was composed of anatase and a minor amount of rutile, whereas the pore size of 20 microm film was about 4-6 microm and was bigger than the others. Furthermore, the small cracks were easy to observe. XRD pattern showed that the Ti peak was significantly reduced and new Ca, P, O containing compound was formed in addition to rutile and anatase with the film thickness increasing. There were significant differences in regard to surface roughness of the three groups. These findings suggest that the film thickness has an intense effect on the quality of the MAO coating. By changing the film thickness, we can extensively change the composition, structure and chemical properties of the surface layer on titanium. PMID:20481318

Nie, Rongrong; Zhu, Feng; Shen, Liru; Chen, Zhiqing

2010-04-01

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Sol-gel-derived composite antimony-doped, tin oxide-coated clay-silicate semitransparent and conductive electrodes.  

Science.gov (United States)

A new form of conductive and transparent porous composite electrode is introduced. The electrode material is composed of antimony-doped, tin oxide (ATO)-coated mica platelets imbedded in sol-gel-derived silicate or methyl silicate network. The platelet clays self-align in a layered structure within the silicate film, an anisotropic construction that minimizes the ATO loading required to achieve electric percolation. Transparency and resistance as a function of clay loading is reported with typical values of 100 k Omega/square and 1.5 OD for a 20-microm-thick film. The transparency is lower as compared to sputtered ATO glasses, but this is, as far as we know, the best method for the low-temperature preparation of transparent, porous, and electrically conductive (as opposed to the amply reported ionically conductive) electrode materials. Permselectivity induced by the silicate and clay ingredients is demonstrated by permeation of positively charged methyl viologen compared to negatively charged ferricyanide. Prussian blue-modified ATO-coated platelets dispersed in sol-gel-derived silicate were used to demonstrate feasibility of a transparent and electrically conductive porous electrochromic material. PMID:17555295

Sadeh, A; Sladkevich, S; Gelman, F; Prikhodchenko, P; Baumberg, I; Berezin, O; Lev, O

2007-07-15

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Uranium extraction from sea water with composite adsorbents, (1)  

International Nuclear Information System (INIS)

For the purpose of development of adsorbents for the extraction of uranium from sea water, titanium based composite hydrous oxides were synthesized and their uranium adsorption capacities were investigated. They are composite hydrous oxides of Ti(IV)-Al(III), Ti(IV)-Fe(III), Ti(IV)-Ce(III), Ti(IV)-Cr(III), Ti(IV)-La(III), Ti(IV)-Si(IV), Ti(IV)-Zr(IV) and Ti(IV)-Sn(IV), prepared as precipitation products by addition of sodium hydroxide solution to the mixed solution of titanium tetrachloride and acidic solution of other metal. Adsorption experiments were carried by batch method using sea water in which slight amount of uranyl chloride was added. The initial uranium concentration was 10.1 ?g/l. The composite hydrous Ti(IV)-Fe(III) oxide was found to give the largest uranium adsorption capacity among the composite hydrous oxides and its uranium adsorption capacity per gram of titanium in adsorbent was about twice larger than that of hydrous Ti(IV) oxide alone. Uranium adsorption capacity of composite hydrous Ti(IV)-Al(III) oxide increases with the temperature of precipitation process. The composite hydrous Ti(IV)-Fe(III) oxide shows its maximum uranium adsorption capacity when it was prepared from pH 5 and 7 at 700C. It was found that the composite adsorbent, hydrous Ti(IV)-Fe(III) oxide, had its large uranium adsorption capacity when its mean pore radius was between 20 and 33 A, and its specific surface area was between 250 and 325 m2/g. (author)

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Adsorption Characterization of Strontium on PAN/Zeolite Composite Adsorbent  

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Full Text Available This work reports the adsorption of strontium from aqueous solutions onto PAN/zeolite composite. The strontium adsorption on the composite adsorbent was studied as a function of initial strontium concentration, pH of the solution, contact time and temperature. Adsorption isotherms like Langmuir, Freundlich,Dubinin–Radushkevich (D–R and Temkin were used to analyze the equilibrium data at the different concentrations.Adsorption process well fitted to Temkin isotherm model. Thermodynamic parameters such as the changes in enthalpy, entropy and Gibbs’ free energy were determined, showing adsorption to be an exothermic and spontaneous process.

Sabriye Yusan

2011-04-01

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Oxide coating development  

Energy Technology Data Exchange (ETDEWEB)

Monolithic SiC heat exchangers and fiber-reinforced SiC-matrix composite heat exchangers and filters are susceptible to corrosion by alkali metals at elevated temperatures. Protective coatings are currently being developed to isolate the SiC materials from the corrodants. Unfortunately, these coatings typically crack and spall when applied to SiC substrates. The purpose of this task is to determine the feasibility of using a compliant material between the protective coating and the substrate. The low-modulus compliant layer could absorb stresses and eliminate cracking and spalling of the protective coatings.

Stinton, D.P.

1995-06-01

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Preparation and uranium adsorptivity of the titanium-activated composite flocculent adsorbent  

International Nuclear Information System (INIS)

We have been making a study on the extraction of uranium from seawater with the composite adsorbent which consists of hydrous titanium oxide and activated carbon. In this paper, the titanium-activated carbon flocculent adsorbents were prepared with PAH (polyacrylic acid hydrazide) as a binder, and the uranium adsorptivity of the flocculent adsorbents was examined in seawater. The flocculent adsorbents were found to show a high rate of adsorption for uranium similar to the powdery adsorbent and to adsorb 0.1 mg-U/g for 5 days from natural seawater. (author)

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Adsorption and thermodynamic behavior of uranium(VI) on Ulva sp.-Na bentonite composite adsorbent  

International Nuclear Information System (INIS)

The algae-clay composite adsorbent was tested for its ability to recover U(VI) from diluted aqueous solutions. Macro marine algae (Ulva sp.) and clay (Na bentonite) were used to prepare composite adsorbent. The ability of the composite adsorbent to adsorp uranium(VI) from aqueous solution has been studied at different optimized conditions of pH, concentration of U(VI), temperature, contact time. Parameters of desorption were also investigated to recover the adsorbed uranium. The adsorption patterns of uranium on the composite adsorbent followed the Freundlich and Dubinin-Radushkevich isotherms. The thermodynamic parameters such as the enthalpy ?H, entropy ?S and Gibbs free energy ?G were calculated from the slope and intercept of lnKd vs. 1/T plots. The results suggested that the Ulva sp.-Na bentonite composite adsorbent is suitable as sorbent material for recovery and biosorption/adsorption of uranium ions from aqueous solutions. (author)

18

Recovery of uranium from seawater by composite fiber adsorbent  

International Nuclear Information System (INIS)

The authors of this paper developed a composite fiber adsorbent (CFA) to entrap finely powdered amidoxime into fibrils of supporting material with silica in a previous report. This was further tested for uranyl recovery directly from seawater. The adsorption rate showed a flow rate dependence with almost a saturation value of ?100 ?g of U/g of CFA at a mean flow rate of sea current. Chemical as well as physical deterioration was overcome by using 1 N NaHCO3 and 0.72 M NaCl as liberating and washing agents, to keep the pH and ionic strength, respectively, constant, and the initial adsorption rate was maintained even after a recycle time of 50. A continuous passage of seawater showed a linear increase of the adsorption to afford 1560 ?g of U/g of CFA after 3 weeks

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Characterization of oxide coatings formed on tantalum by plasma electrolytic oxidation in 12-tungstosilicic acid  

Energy Technology Data Exchange (ETDEWEB)

Oxide coatings were formed on tantalum by plasma electrolytic oxidation (PEO) process in 12-tungstosilicic acid. The PEO process can be divided into three stages with respect to change of the voltage-time response. The contribution of electron current density in total current density during anodization results in the transformation of the slope of voltage-time curve. The surface morphology, chemical and phase composition of oxide coatings were investigated by AFM, SEM-EDX, XRD and Raman spectroscopy. Oxide coating morphology is strongly dependent of PEO time. The elemental components of PEO coatings are Ta, O, Si and W. The oxide coatings are partly crystallized and mainly composed of WO{sub 3}, Ta{sub 2}O{sub 5} and SiO{sub 2}. Raman spectroscopy showed that the outer layer of oxide coatings formed during the PEO process is silicate tungsten bronze.

Petkovic, M. [Faculty of Physics, University of Belgrade, Studentski trg 12-16, 11000 Belgrade (Serbia); Stojadinovic, S., E-mail: sstevan@ff.bg.ac.rs [Faculty of Physics, University of Belgrade, Studentski trg 12-16, 11000 Belgrade (Serbia); Vasilic, R. [Faculty of Environmental Governance and Corporate Responsibility, Educons University, Vojvode Putnika bb, Sremska Kamenica (Serbia); Zekovic, Lj. [Faculty of Physics, University of Belgrade, Studentski trg 12-16, 11000 Belgrade (Serbia)

2011-10-01

20

Characterization of oxide coatings formed on tantalum by plasma electrolytic oxidation in 12-tungstosilicic acid  

Science.gov (United States)

Oxide coatings were formed on tantalum by plasma electrolytic oxidation (PEO) process in 12-tungstosilicic acid. The PEO process can be divided into three stages with respect to change of the voltage-time response. The contribution of electron current density in total current density during anodization results in the transformation of the slope of voltage-time curve. The surface morphology, chemical and phase composition of oxide coatings were investigated by AFM, SEM-EDX, XRD and Raman spectroscopy. Oxide coating morphology is strongly dependent of PEO time. The elemental components of PEO coatings are Ta, O, Si and W. The oxide coatings are partly crystallized and mainly composed of WO 3, Ta 2O 5 and SiO 2. Raman spectroscopy showed that the outer layer of oxide coatings formed during the PEO process is silicate tungsten bronze.

Petkovi?, M.; Stojadinovi?, S.; Vasili?, R.; Zekovi?, Lj.

2011-10-01

 
 
 
 
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Characterization of oxide coatings formed on tantalum by plasma electrolytic oxidation in 12-tungstosilicic acid  

International Nuclear Information System (INIS)

Oxide coatings were formed on tantalum by plasma electrolytic oxidation (PEO) process in 12-tungstosilicic acid. The PEO process can be divided into three stages with respect to change of the voltage-time response. The contribution of electron current density in total current density during anodization results in the transformation of the slope of voltage-time curve. The surface morphology, chemical and phase composition of oxide coatings were investigated by AFM, SEM-EDX, XRD and Raman spectroscopy. Oxide coating morphology is strongly dependent of PEO time. The elemental components of PEO coatings are Ta, O, Si and W. The oxide coatings are partly crystallized and mainly composed of WO3, Ta2O5 and SiO2. Raman spectroscopy showed that the outer layer of oxide coatings formed during the PEO process is silicate tungsten bronze.

22

Iron oxide coated gold nanorods: synthesis, characterization, and magnetic manipulation.  

Science.gov (United States)

We report a simple process to generate iron oxide coated gold nanorods. Gold nanorods, synthesized by our three-step seed mediated protocol, were coated with a layer of polymer, poly(sodium 4-styrenesulfonate). The negatively charged polymer on the nanorod surface electrostatically attracted a mixture of aqueous iron(II) and iron(III) ions. Base-mediated coprecipitation of iron salts was used to form uniform coatings of iron oxide nanoparticles onto the surface of gold nanorods. The magnetic properties were studied using a superconducting quantum interference device (SQUID) magnetometer, which indicated superparamagnetic behavior of the composites. These iron oxide coated gold nanorods were studied for macroscopic magnetic manipulation and were found to be weakly magnetic. For comparison, premade iron oxide nanoparticles, attached to gold nanorods by electrostatic interactions, were also studied. Although control over uniform coating of the nanorods was difficult to achieve, magnetic manipulation was improved in the latter case. The products of both synthetic methods were monitored by UV-vis spectroscopy, zeta potential measurements, and transmission electron microscopy. X-ray photoelectron spectroscopy was used to determine the oxidation state of iron in the gold nanorod-iron oxide composites, which is consistent with Fe2O3 rather than Fe3O4. The simple method of iron oxide coating is general and applicable to different nanoparticles, and it enables magnetic field-assisted ordering of assemblies of nanoparticles for different applications. PMID:18484755

Gole, Anand; Stone, John W; Gemmill, William R; zur Loye, Hans-Conrad; Murphy, Catherine J

2008-06-17

23

AMMONIA AND COD REMOVAL FROM SYNTHETIC LEACHATE USING RICE HUSK COMPOSITE ADSORBENT  

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Ammonia and chemical oxygen demand (COD) were the most two problematic parameters in the landfill leachate. In this study, a new composite adsorbent derived from rice husk ash waste is evaluated with respect to its ability to remove these contaminants from synthetic leachate. Results indicate that the new composite adsorbent is able to adsorb both ammonia and COD. It has a higher adsorption capacity for ammonia (Q = 2.2578 mg/g) and an almost equal adsorption capacity for COD (Q = 2.8893) whe...

Azhar Abdul Halim; Noor Nazurah Zainal Abidin; Normah Awang; Anuar Ithnin; Mohd Sham Othman; Mohd Ikram Wahab

2011-01-01

24

Effect of sandblasting intensity on microstructures and properties of pure titanium micro-arc oxidation coatings in an optimized composite technique  

Science.gov (United States)

Sandblasting is one of the most effective methods to modify a metal surface and improve its properties for application. Micro-arc oxidation (MAO) could produce a ceramic coating on a dental implant, facilitating cellular differentiation and osseocomposite on it. This study aims to deposit bioceramic Ca- and P-containing coatings on sandblasted commercially pure titanium by an optimum composite technique to improve the bioactive performance. The effect of sandblasting intensity on microstructures and properties of the implant coatings is examined, and the modified surfaces are characterized in terms of their topography, phase, chemical composition, mechanical properties and hydroxyapatite (HA)-inducing ability. The results show that a moderate sandblasting micromachines the substrate in favorable combination of rough and residual stresses; its MAO coating deposits nano-hydroxyapatite after immersion in simulated body fluid (SBF) for 5 days exhibiting better bioactivity. The further improvement of the implant surface performance is attributed to an optimized composite technique.

Wang, Hong-Yuan; Zhu, Rui-Fu; Lu, Yu-Peng; Xiao, Gui-Yong; He, Kun; Yuan, Y. F.; Ma, Xiao-Ni; Li, Ying

2014-02-01

25

AMMONIA AND COD REMOVAL FROM SYNTHETIC LEACHATE USING RICE HUSK COMPOSITE ADSORBENT  

Directory of Open Access Journals (Sweden)

Full Text Available Ammonia and chemical oxygen demand (COD were the most two problematic parameters in the landfill leachate. In this study, a new composite adsorbent derived from rice husk ash waste is evaluated with respect to its ability to remove these contaminants from synthetic leachate. Results indicate that the new composite adsorbent is able to adsorb both ammonia and COD. It has a higher adsorption capacity for ammonia (Q = 2.2578 mg/g and an almost equal adsorption capacity for COD (Q = 2.8893 when compared with commercially activated carbon. The adsorption kinetics of this new product for ammonia and COD were primarily represented by the pseudo second-order mechanism. The overall adsorption rate of the ammonia and COD adsorption processes appears to be determined by chemisorption process. The regenerated composite adsorbent indicated higher adsorption capacities of ammonia and COD, i.e. 12.9366 mg/g and 3.1162 mg/g, respectively.

Azhar Abdul Halim

2011-06-01

26

Preparation and Property of SiC/(ZrB2-SiC/SiC4 Anti-oxidation Coatings for Cf/SiC Composites  

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Full Text Available A SiC/(ZrB2-SiC/SiC4 coating was prepared by slurry painting and pulse CVD. The composition and structure of the coating were studied by using XRD,SEM and EDS analysis, then the anti-oxidation property of the coating was investigated. The results show that the thickness of obtained coating is about 100¦?, ZrB2-SiC layer and Pulse CVD SiC layer are bonded to each other alternately. After oxidation at 1500¡?n air for 25h, the weight loss of the Pulse CVD coating is 5.1%, while weight gain of the SiC/(ZrB2-SiC/SiC4 coating is about 2.5%. The SiC/(ZrB2-SiC/SiC4 coating shows excellent antiª²oxidation property.

WU Ding-Xing,DONG Shao-Ming,DING Yu-Sheng,ZHANG Xiang-Yu,WANG Zheng,ZHOU Hai-Jun

2009-07-01

27

In situ toughened SiC ceramics with Al-B-C additions and oxide-coated SiC platelet/SiC composites  

Energy Technology Data Exchange (ETDEWEB)

This work aimed at fabrication and characterization of high toughness SiC ceramics through the applications of in situ toughening and SiC platelet reinforcement. The processing-microstructure-property relations of hot pressed SiC with Al, B, and C additions (designated as ABC-SiC) were investigated. Through a liquid phase sintering mechanism, dense SiC was obtained by hot pressing at a temperature as low as 1,700 C with 3 wt% Al, 0.6 wt% B, and 2 wt% C additions. These sintering aids also enhanced the {beta}-to-{alpha} (3C-to-4H) phase transformation, which promoted SiC grains to grow into plate-like shapes. Under optimal processing conditions, the microstructure exhibited high-aspect-ratio plate-shaped grains with a thin (< 1 nm) Al-containing amorphous grain boundary film. The mechanical properties of the toughened SiC and the composites were evaluated in comparison with a commercial Hexoloy SiC under identical test conditions. The C-curve behavior was examined using the strength-indentation load relationship and compared with that directly measured using precracked compact tension specimens. The in situ toughened ABC-SiC exhibited much improved flaw tolerance and a significantly rising R-curve behavior. A steady-state toughness in excess of 9 MPam{sup 1/2} was recorded for the ABC-SiC in comparison to a single valued toughness below 3 MPam{sup 1/2} for the Hexoloy. Toughening in the ABC-SiC was mainly attributed to grain bridging and subsequent pullout of the plate-shaped grains. The high toughness ABC-SiC exhibited a bend strength of 650 MPa with a Weibull modulus of 19; in comparison, the commercial SiC showed a bend strength of 400 MPa with a Weibull modulus of 6. Higher fracture toughness was also achieved by the reinforcement of SiC platelets, encapsulated with alumina, yttria, or silica, in a SiC matrix.

Cao, J. [Univ. of California, Berkeley, CA (United States). Dept. of Materials Science and Mineral Engineering]|[Lawrence Berkeley National Lab., CA (United States). Materials Sciences Div.

1996-12-01

28

Properties and uranium adsorptive property of the granulated titanium-activated carbon composite adsorbent with polyacrylic acid hydrazide (PAH)  

International Nuclear Information System (INIS)

Granulation of the composite adsorbent which consisted of hydrous titanium oxide and activated carbon was studied with PAH as a binder and the adsorptive property for uranium from sea water was examined. The strength of the granulated composite adsorbent with PAH increased as the degree of hydrazidation and amount of addition of PAH increased. The strength of the granulated composite adsorbent in break-down test by shaking method showed 98% at 10% added PAH with the degree of hydrazidation of 73%. PAH as the binder in the granulated composite adsorbent did not inhibited the adsorption of uranium from sea water, whereas the inhibitory effect of polyvinyl alcohol as a binder was found after formalization. The rate of adsorption of uranium on the granulated composite adsorbent was inversely proportional to the radius of granular. The granulated composite adsorbent was not disintegrated in elution process of uranium with acid or alkali carbonate solutions. (author)

29

Properties and uranium adsorptivity of the aluminium-activated carbon composite adsorbent and aluminium hydroxide  

International Nuclear Information System (INIS)

The effect of hydrolysis temperature of aluminium chloride on the properties of the products was studied to clear the uranium adsorptivity of the composite adsorbent (C-Al-OH). The aluminium hydroxide prepared at low temperature indicated a X-ray diffraction pattern of byerite. The X-ray diffraction intensity of byerite decreased and the intensity of pseudo-boehmite increased with increasing the hydrolysis temperature. Several adsorbents which were crystalline revealed low adsorptive capacity for uranium. The adsorptive capacity of the aluminium hydroxide for uranium was closely proportional to the surface area and the alkaline consumption, but was not related to the pore size distribution. On the other hand, the adsorptive capacity of the composite adsorbent was related to the volume of pores larger than 100 A in radius. (auth.)

30

Desorption of uranium from titanium-activated carbon composite adsorbent with acidic eluent, 2  

International Nuclear Information System (INIS)

The desorption of uranium from the granular titanium-activated carbon composite adsorbent (concentration of uranium: 25.5 mg/l-Ad), which adsorbed uranium from natural sea water, was examined by the column process with acidic eluent at room temperature. The column operation was able to be carried out without destruction of the granular adsorbent by the generation of the carbon dioxide, and free from disturbance of the eluent flow by precipitate of calcium sulfate dihydrate with sulfuric acid eluent. The amount of acid consumption by the adsorbent was 0.87 eq/l-Ad. The alkaline earth metals were eluted in the range of elution volume below 2l/l-Ad, whereas uranium, iron, and titanium were eluted above 2l/l-Ad. Therefore, uranium was separable from the alkaline earth metals which were adsorbed in the most quantity in the adsorbent. In the range of elution volume 2 to 12l/l-Ad, the percentage of desorbed uranium and the concentration ratio of uranium were 80%, 680 with 0.5 N sulfuric acid, and 59%, 490 with 0.5 N hydrochloric acid respectively. The percentage of dissolved titanium (DTI) was 0.3% with 0.5 N sulfuric acid, 0.26% with 0.5 N hydrochloric acid in the same range. (author)

31

Desorption of uranium from titanium-activated carbon composite adsorbent with acidic eluent, 1  

International Nuclear Information System (INIS)

An investigation was carried out on the desorption of uranium from titanium-activated carbon composite adsorbent with acidic eluent by the batch process. The rate of desorption of uranium with acidic eluent depended on temperature, showing an increase as the temperature was raised. But the rate of desorption with acidic eluent was less dependent on temperature than that obtained when mixed eluent of sodium carbonate-sodium hydrogencarbonate was used. The rate of desorption of uranium did not vary in the range of concentration from 0.3 to 0.5 N, and the rate of desorption with sulfuric acid was slightly higher than that obtained when hydrochloric acid was used. The amount of dissolved titanium decreased as the ratio of adsorbent to eluent (RAE) was increased. At RAE of 10 %, the percentage of dissolved titanium (DTI) was below 0.38 % with sulfuric acid, below 0.7 % with hydrochloric acid. These values were found to be higher than the ones with the carbonate eluent. The elements except uranium, which were adsorbed on the adsorbent, were eluted simultaneously with acidic eluent. The regeneration of the adsorbent after desorption, therefore, was found to be unnecessary. In a repeated test of adsorption-desorption treatment up to five times, the percentage of uranium adsorbed from natural sea water was approximately constant of 85 %. From these results, the application of column process to the desorption of uranium with acidic eluent at room temperature was proposed to be feasible. (author)

32

Desorption of uranium from titanium-activated carbon composite adsorbent with acidic eluent, 2  

International Nuclear Information System (INIS)

The desorption of uranium from the granular titanium-activated carbon composite adsorbent (concentration of uranium: 25.5 mg/1-Ad), which adsorbed uranium from natural sea water, was examined by the column process with acidic eluent at room temperature. The column operation was able to be carried out without destruction of the granular adsorbent by the generation of the carbon dioxide, and free from disturbance of the eluent flow by precipitate of calcium sulfate dihydrate with sulfuric acid eluent. The amount of acid consumption by the adsorbent was 0.87 eq/1-Ad. The alkaline earth metals were eluted in the range of elution volume below 2 1/1-Ad, whereas uranium, iron, and titanium were eluted above 2 1/1-Ad. Therefore, uranium was separable from the alkaline earth metals which were adsorbed in the most quantity in the adsorbent. In the range of elution volume 2 to 12 1/1-Ad, the percentage of desorbed uranium and the concentration ratio of uranium were 80 %, 680 with 0.5 N sulfuric acid, and 59 %, 490 with 0.5 N hydrochloric acid, respectively. The percentage of dissolved titanium (DTI) was 0.3 % with 0.5 N sulfuric acid, 0.26 % with 0.5 N hydrochloric acid in the same range. (author)

33

Desorption of uranium from titanium-activated carbon composite adsorbent with acidic eluent, (1)  

International Nuclear Information System (INIS)

An investigation was carried out on the desorption of uranium from titanium-activated carbon composite adsorbent with acidic eluent by the batch process. The rate of desorption of uranium with acidic eluent depended on temperature, showing an increase as the temperature was raised. But the rate of desorption with acidic eluent was less dependent on temperature than that obtained when mixed eluent of sodium carbonate-sodium hydrogencarbonate was used. The difference of the rate of desorption of uranium in the range of concentration from 0.3 to 0.5N was not found, and the rate of desorption with sulfuric acid was slightly higher than that obtained when hydrochloric acid was used. The amount of dissolved titanium decreased as the ratio of adsorbent to eluent (RAE) was increased. At RAE of 10%, the percentage of dissolved titanium (DTI) was below 0.38% with sulfuric acid, below 0.7% with hydrochloric acid. These values were found to be higher than the ones with the carbonate eluent. The elements except uranium, which were adsorbed on the adsorbent, were eluted simultaneously with acidic eluent. The regeneration of the adsorbent after desorption, therefore, was found to be unnecessary. In a repeated test of adsorption-desorption treatment up to five times, the percentage of uranium adsorbed from natural sea water was approximately constant of 85%. From these results, the application of column process to the desorption of uranium with acidic eluent at room temperature was proposed to be feasible. (author)

34

ADSORPTION OF Cr(VI) FROM AQUEOUS SOLUTION USING CARBON-MICROSILICA COMPOSITE ADSORBENT  

Scientific Electronic Library Online (English)

Full Text Available SciELO Chile | Language: English Abstract in english In this work, Microsilica, one kind of industry solid waste material, was utilized firstly to prepare a carbon-Microsilica composite adsorbent from a partial carbonization, mixture and sulfoxidation process and was proposed for the removal of Cr(VI) from solutions. The surface chemistry characterist [...] ics of the prepared adsorbent were analysis by XPS and FT-IR. The characterization results indicated that an abundant of oxygen functional groups, such as hydroxyl, carboxyl and sulfonic groups, were introduced into the surface of the prepared composite adsorbent. Meanwhile, the adsorption characteristics of Cr(VI) onto the adsorbent in aqueous solutions was studied as a function of solution pH, ionic strength, contact time, and temperature. The results showed that Cr(VI) adsorption onto the adsorbent is strongly dependent on pH and, to a lesser extent, ionic strength. Kinetics data were found to follow the pseudo-second-order kinetic model while the adsorption data corresponded to L-shape adsorption isotherm which corresponds to the classification of Giles. Activation thermodynamic parameters, such as activation enthalpy (?H*), activation entropy (?S*), activation Gibbs free energy (?G*) and activation energy (E), have been evaluated and the possible adsorption mechanism also was suggested.

DEYI, ZHANG; YING, MA; HUIXIA, FENG; YUAN, HAO.

2012-03-01

35

ADSORPTION OF Cr(VI FROM AQUEOUS SOLUTION USING CARBON-MICROSILICA COMPOSITE ADSORBENT  

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Full Text Available In this work, Microsilica, one kind of industry solid waste material, was utilized firstly to prepare a carbon-Microsilica composite adsorbent from a partial carbonization, mixture and sulfoxidation process and was proposed for the removal of Cr(VI from solutions. The surface chemistry characteristics of the prepared adsorbent were analysis by XPS and FT-IR. The characterization results indicated that an abundant of oxygen functional groups, such as hydroxyl, carboxyl and sulfonic groups, were introduced into the surface of the prepared composite adsorbent. Meanwhile, the adsorption characteristics of Cr(VI onto the adsorbent in aqueous solutions was studied as a function of solution pH, ionic strength, contact time, and temperature. The results showed that Cr(VI adsorption onto the adsorbent is strongly dependent on pH and, to a lesser extent, ionic strength. Kinetics data were found to follow the pseudo-second-order kinetic model while the adsorption data corresponded to L-shape adsorption isotherm which corresponds to the classification of Giles. Activation thermodynamic parameters, such as activation enthalpy (?H*, activation entropy (?S*, activation Gibbs free energy (?G* and activation energy (E, have been evaluated and the possible adsorption mechanism also was suggested.

DEYI ZHANG

2012-03-01

36

ADSORPTION OF Cr(VI) FROM AQUEOUS SOLUTION USING CARBON-MICROSILICA COMPOSITE ADSORBENT  

Scientific Electronic Library Online (English)

Full Text Available SciELO Chile | Language: English Abstract in english In this work, Microsilica, one kind of industry solid waste material, was utilized firstly to prepare a carbon-Microsilica composite adsorbent from a partial carbonization, mixture and sulfoxidation process and was proposed for the removal of Cr(VI) from solutions. The surface chemistry characterist [...] ics of the prepared adsorbent were analysis by XPS and FT-IR. The characterization results indicated that an abundant of oxygen functional groups, such as hydroxyl, carboxyl and sulfonic groups, were introduced into the surface of the prepared composite adsorbent. Meanwhile, the adsorption characteristics of Cr(VI) onto the adsorbent in aqueous solutions was studied as a function of solution pH, ionic strength, contact time, and temperature. The results showed that Cr(VI) adsorption onto the adsorbent is strongly dependent on pH and, to a lesser extent, ionic strength. Kinetics data were found to follow the pseudo-second-order kinetic model while the adsorption data corresponded to L-shape adsorption isotherm which corresponds to the classification of Giles. Activation thermodynamic parameters, such as activation enthalpy (?H*), activation entropy (?S*), activation Gibbs free energy (?G*) and activation energy (E), have been evaluated and the possible adsorption mechanism also was suggested.

DEYI, ZHANG; YING, MA; HUIXIA, FENG; YUAN, HAO.

37

TEM Analysis on Micro-Arc Oxide Coating on the Surface of Magnesium Alloy  

Science.gov (United States)

By micro-arc oxidation (MAO), the oxide coatings were prepared on the surface of magnesium alloys in a composite electrolytic solution. The microstructures of the coating layer and the interface between coating and substrate were analyzed by using transmission electron microscopy (TEM) and scanning electron microscopy (SEM). The oxide coating consists of two layers (the outer and the inner layer). Although both layers are composed of microcrystalline MgO and amorphous phase, the inner layer is more compact and rich in fluorine with a thickness of about 1-2 ?m. Fluorine plays an important role in the inner dense layer formation. The inner layer, like a barrier wall, blocks the thickness of the oxide coating to increase and improves corrosion resistance. The formation mechanism of the inner layer is also discussed.

Huang, Yuan-Sheng; Liu, Hong-Wei

2011-04-01

38

Adsorption properties of Cs{sup +} for composite adsorbents and their irradiation stabilities  

Energy Technology Data Exchange (ETDEWEB)

Novel composite adsorbents using impregnation-precipitation methods have been developed; these fine crystals are loaded in the macro-pores of porous silica gels and zeolites. The 2 following composite adsorbents: KCoFC-NM (NM: natural mordenite, 0.4-1.0 mm), KCoFC-SG (SG: porous silica gel, NH and Q-10)) were prepared by impregnation-precipitation methods. This article presents the results of tests about their characterization, their selective adsorption ability of Cs{sup 137} and their irradiation stability. It is shown that the KCoFC-SG and KCoFC-NM composites are thus efficient for the selective separation of Cs{sup 137} in low-level radioactive waste (LLW) containing highly concentrated sodium nitrate.

Susa, Shunsuke; Mimura, Hitoshi [Tohoku University, Aramaki-Aza-Aoba 6-6, Aoba-ku, Sendai, Miyagi 980-8579 (Japan); Ito, Yoshiyuki; Saito, Yasuo [Japan Atomic Energy Agency, Muramatsu 4-33, Tokai-mura, Naka-gun, Ibaraki 319-1194 (Japan)

2013-07-01

39

Adsorption properties of Cs+ for composite adsorbents and their irradiation stabilities  

International Nuclear Information System (INIS)

Novel composite adsorbents using impregnation-precipitation methods have been developed; these fine crystals are loaded in the macro-pores of porous silica gels and zeolites. The 2 following composite adsorbents: KCoFC-NM (NM: natural mordenite, 0.4-1.0 mm), KCoFC-SG (SG: porous silica gel, NH and Q-10)) were prepared by impregnation-precipitation methods. This article presents the results of tests about their characterization, their selective adsorption ability of Cs137 and their irradiation stability. It is shown that the KCoFC-SG and KCoFC-NM composites are thus efficient for the selective separation of Cs137 in low-level radioactive waste (LLW) containing highly concentrated sodium nitrate

40

Fabrication, characterization, and application of a composite adsorbent for simultaneous removal of arsenic and fluoride.  

Science.gov (United States)

Coexisting arsenic (As) and fluoride (F) in groundwater poses severe health risks worldwide. Highly efficient simultaneous removal of As and F is therefore of great urgency and high priority. The purpose of this study was to fabricate a novel composite adsorbent and explore the mechanism for concurrent removal of As(V) and F at the molecular level. This bifunctional adsorbent with titanium and lanthanum oxides impregnated on granular activated carbon (TLAC) exhibits a pronounced As(V) and F adsorption capacity over commercially available iron- and aluminum-based adsorbents for synthetic and real contaminated groundwater samples. Synchrotron-based X-ray microfluorescence analysis demonstrates that La and Ti were homogeneously distributed on TLAC. Extended X-ray absorption fine structure spectroscopic results suggest that As(V) formed bidentate binuclear surface complex as evidenced by an averaged Ti-As bond distance of 3.34 Å in the presence of F. Adsorption tests and Fourier transform infrared spectroscopy analysis indicate that F was selectively adsorbed on lanthanum oxides. The surface configurations constrained with the spectroscopic results were formulated in the charge distribution multisite complexation model to describe the competitive adsorption behaviors of As(V) and F. The results of this study indicate that TLAC could be used as an effective adsorbent for simultaneous removal of As(V) and F. PMID:22235839

Jing, Chuanyong; Cui, Jinli; Huang, Yuying; Li, Aiguo

2012-02-01

 
 
 
 
41

Moisture transport and adsorption on silica gel-calcium chloride composite adsorbents  

International Nuclear Information System (INIS)

A measurement of moisture uptake curves in silica gel-calcium composite adsorbents is performed by using the thermal gravimetrical method in a relative vapor pressure range from 0.5 to 0.9 at different temperature levels of 25, 35 and 45 deg. C, respectively. Also, dynamic adsorption curves individually corresponding to the temperature and relative pressure conditions of (25 deg. C, 0.7) (35 deg. C, 0.7) and (35 deg. C, 0.5) have been measured. This experimental study shows that the sorption rate is highest for non-impregnated macroporous silica gel; however, the same silica gel impregnated with calcium chloride has a much greater final water loading. This confirms that composite adsorbents result in a better adsorption performance compared with non-impregnated silica gel, leading to a trade off in finalizing the content of CaCl2 in the composite. Through theoretical analysis on the experimental data, it is found that the saturated adsorption data can be well fitted by the FHH model and the dynamic adsorption data well fitted by the Crank diffusion model, simultaneously yielding the effective solid side mass diffusivities. A comparison with these obtained diffusion coefficients further supports that the mass diffusivity in the composite adsorbent also increases with an increase in temperature, as well as in humidity, but drastically decreases due to the presence of salt inside the matrix pores compared with the non-impregnated host matrix

42

Development of Composite Adsorbents for LLW Treatment and Their Adsorption Properties for Cs and Sr - 13127  

International Nuclear Information System (INIS)

In this study, the composite adsorbents (KCoFC-NM (NM: natural mordenite), KCoFC-SG (SG: porous silica gel), AMP-SG and so on) were prepared by impregnation-precipitation methods. As for the distribution properties, the largest Kd,Cs value of 3.8 x 104 cm3/g was obtained for KCoFC-SG (Davi.) composite. KCoFC-SG (NH, MB5D) and T-KCFC also had relatively large Kd,Cs values above 1.0 x 104 cm3/g. The uptake rate of Cs+ ions was examined by batch method. KCoFC-SG (NH, MB5D) and AMP-SG (Davi.) had relatively large uptake rate of Cs+, and the uptake attained equilibrium within 1 h. The maximum uptake capacity of Cs+ ions was estimated to be above 0.5 mmol/g for KCoFC-NM and KCoFC-CP composites. KCoFC-X composite had a relatively large uptake capacity of Cs+ ions (0.23 mmol/g > 0.17 mmol/g (T-KCFC)) and this composite also had a selectivity towards Sr2+ ions; KCoFC-X is effective adsorbent for both Cs+ and Sr2+ ions. The largest value of Kd,Sr was estimated to be 218 cm3/g for titanic acid-PAN. Titanic acid-PAN had the largest uptake rate of Sr2+ ions, and the uptake attained equilibrium within 8 h. Adsorbability of other nuclides was further examined by batch method. All adsorbents had adsorbability for Rb+ and RuNO3+ ions. KCoFC-SG (NH), KCoFC-CP and T-KCFC had higher selectivity towards Cs+ than other adsorbents; these adsorbents had adsorbability to Cs+ ions even in the presence of Ba2+, Ca2+ and Mg2+ ions. The separation factor of Kd,Sr/Kd,Ba for titanic acid-PAN was about 1, indicating that the Kd,Sr for titanic acid-PAN tends to decrease with Ba2+ concentration. As for the breakthrough properties, the largest 5 % breakpoint and 5 % breakthrough capacity of Cs+ ions were estimated to be 47.1 cm3 and 0.07 mmol/g for the column of KCoFC-SG (NH), respectively. The order of 5 % breakthrough capacity of Cs+ is as follows; KCoFC-SG (NH) > KCoFC-NM > KCoFC-SG (Q-10) > T-KCFC > KCoFC-X > KCoFC-CP. From the results of batch and column experiments, the composite adsorbent of KCoFC-SG (NH) was effective for the uptake of Cs+ ions, and KCoFC-X composite was useful for the uptake of both Cs+ and Sr2+ ions. The estimation of irradiation stability and the uptake properties using the actual wastes are further essential for the practical operation. (authors)

43

Development of Composite Adsorbents for LLW Treatment and Their Adsorption Properties for Cs and Sr - 13127  

Energy Technology Data Exchange (ETDEWEB)

In this study, the composite adsorbents (KCoFC-NM (NM: natural mordenite), KCoFC-SG (SG: porous silica gel), AMP-SG and so on) were prepared by impregnation-precipitation methods. As for the distribution properties, the largest K{sub d,Cs} value of 3.8 x 10{sup 4} cm{sup 3}/g was obtained for KCoFC-SG (Davi.) composite. KCoFC-SG (NH, MB5D) and T-KCFC also had relatively large K{sub d,Cs} values above 1.0 x 10{sup 4} cm{sup 3}/g. The uptake rate of Cs{sup +} ions was examined by batch method. KCoFC-SG (NH, MB5D) and AMP-SG (Davi.) had relatively large uptake rate of Cs{sup +}, and the uptake attained equilibrium within 1 h. The maximum uptake capacity of Cs{sup +} ions was estimated to be above 0.5 mmol/g for KCoFC-NM and KCoFC-CP composites. KCoFC-X composite had a relatively large uptake capacity of Cs{sup +} ions (0.23 mmol/g > 0.17 mmol/g (T-KCFC)) and this composite also had a selectivity towards Sr{sup 2+} ions; KCoFC-X is effective adsorbent for both Cs{sup +} and Sr{sup 2+} ions. The largest value of K{sub d,Sr} was estimated to be 218 cm{sup 3}/g for titanic acid-PAN. Titanic acid-PAN had the largest uptake rate of Sr{sup 2+} ions, and the uptake attained equilibrium within 8 h. Adsorbability of other nuclides was further examined by batch method. All adsorbents had adsorbability for Rb{sup +} and RuNO{sup 3+} ions. KCoFC-SG (NH), KCoFC-CP and T-KCFC had higher selectivity towards Cs{sup +} than other adsorbents; these adsorbents had adsorbability to Cs{sup +} ions even in the presence of Ba{sup 2+}, Ca{sup 2+} and Mg{sup 2+} ions. The separation factor of K{sub d,Sr}/K{sub d,Ba} for titanic acid-PAN was about 1, indicating that the K{sub d,Sr} for titanic acid-PAN tends to decrease with Ba{sup 2+} concentration. As for the breakthrough properties, the largest 5 % breakpoint and 5 % breakthrough capacity of Cs{sup +} ions were estimated to be 47.1 cm{sup 3} and 0.07 mmol/g for the column of KCoFC-SG (NH), respectively. The order of 5 % breakthrough capacity of Cs{sup +} is as follows; KCoFC-SG (NH) > KCoFC-NM > KCoFC-SG (Q-10) > T-KCFC > KCoFC-X > KCoFC-CP. From the results of batch and column experiments, the composite adsorbent of KCoFC-SG (NH) was effective for the uptake of Cs{sup +} ions, and KCoFC-X composite was useful for the uptake of both Cs{sup +} and Sr{sup 2+} ions. The estimation of irradiation stability and the uptake properties using the actual wastes are further essential for the practical operation. (authors)

Susa, Shunsuke; Mimura, Hitoshi [Dept. of Quantum Science and Energy Engineering, Graduate School of Engineering, Tohoku University, Aramaki-Aza-Aoba 6-6-01-2, Sendai, 980-8579 (Japan); Ito, Yoshiyuki; Saito, Yasuo [Nuclear Science and Engineering Directorate, Japan Atomic Energy Agency, 2-4 Shirakata Shirone, Naka-gun, Ibaraki, 319-1195 (Japan)

2013-07-01

44

A method for preparing ferric activated carbon composites adsorbents to remove arsenic from drinking water  

International Nuclear Information System (INIS)

Iron oxide/activated carbon (FeO/AC) composite adsorbent material, which was used to modify the coal-based activated carbon (AC) 12 x 40, was prepared by the special ferric oxide microcrystal in this study. This composite can be used as the adsorbent to remove arsenic from drinking water, and Langmuir isotherm adsorption equation well describes the experimental adsorption isotherms. Then, the arsenic desorption can subsequently be separated from the medium by using a 1% aqueous NaOH solution. The apparent characters and physical chemistry performances of FeO/AC composite were investigated by X-ray diffraction (XRD), nitrogen adsorption, scanning electron microscopy (SEM) and X-ray photoelectron spectroscopy (XPS). Batch and column adsorption experiments were carried out to investigate and compare the arsenic removal capability of the prepared FeO/AC composite material and virgin activated carbon. It can be concluded that: (1) the main phase present in this composite are magnetite (Fe3O4), maghemite (?-Fe2O3), hematite (?-Fe2O3) and goethite (?-FeO(OH)); (2) the presence of iron oxides did not significantly affect the surface area or the pore structure of the activated carbon; (3) the comparisons between the adsorption isotherms of arsenic from aqueous solution onto the composite and virgin activated carbon showed that the FeO/AC composite behave an excellent capacity of adsorption arsenic than the viacity of adsorption arsenic than the virgin activated carbon; (4) column adsorption experiments with FeO/AC composite adsorbent showed that the arsenic could be removed to below 0.01 mg/L within 1250 mL empty bed volume when influent concentration was 0.5 mg/L

45

A Comparative Study of Agarose-Nickel prototype Composite Adsorbent and Commercial Streamline DEAE Adsorbent: Physical and Hydrodynamical Assessments  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Expanded bed adsorption (EBA) is an integration technology for capturing target bioproducts directly from unclarified feedstock, designing and applying a good adsorbent affects its performance. In present work, a novel matrix has been developed for expanded bed adsorption process. The prepared matrix was manufactured using water-in-oil emulsification method. Desirable adsorbents tend to be of small size, high density as well as high porosity. Here, the prepared matrices had regular spherical ...

Asghari, F.; Jahanshahi, M.; Ghoreyshi, A. A.

2012-01-01

46

The development of composite adsorbent for organic waste decomposion treatment and chemical recovery  

Energy Technology Data Exchange (ETDEWEB)

Up to now inorganic adsorbents has been known to effective for treatment of radioactive waste containing metal ions due to their high selectivity toward the specific ions(Cs{sup +}, Sr{sup 2+}, Co{sup 2+}, Ag{sup +} ...). The draw back of this adsorption system is in the operation difficulties such as separation of fine solids (adsorbents) and pressure drop ({delta}p) problem. To come over these problems, preparation of composite adsorbents has been attempted. In our study, PAN-inorganic ion exchanger(Ni{sub 2}Fe(Cn){sub 6}, K{sub 2}Ti{sub 4}O{sub 9}) composite beads were prepared in the range of 0.5 {approx} 3.5mm in size. The selectivity for Ag{sup +}, Sr{sup 2+}, Cs{sup +} and Co{sup 2+} ions in binary and tertiary systems in composite beads was Sr{sup 2+}>Ag{sup +}, Ag{sup +}>Co{sup 2+}, Co{sup 2+}>Sr{sup 2+} and Sr{sup 2+}>Co{sup 2+}>Ag{sup +} respectively. As an selective Cs{sup +} adsorbent, 1,3-Dipropyloxycalix(4)arene crown ether (CCE1) and 1,3-Dipropyl-oxycalix(4)arene dibenzo crown ethers(CCE2) were also successfully synthesized in the fixed 1,3-alternate conformation with good yields by the reaction of corresponding 1,3-Dipropyloxy-calix(4)arenes 3 with pentaethylene glycol ditosylate and dibenzodimesylate 7, respectively in acetonitrile in the presence of cesium carbonate as a base. Solvent extraction of cesium picrates and cesium nitrate from aqueous solutions into chloroform were investigated. (author). 37 refs., 60 figs., 7 tabs.

Gun, Shul Yong; Jung, Kyeong Taek; Kim, Hyung Tae; Kim, Ki Wook; Kim, Hyun Jong [Yonsei University, Seoul (Korea); Kim, Jong [Konyang University, Nonsan (Korea)

1999-01-01

47

Synthesis and properties of a magnetic core-shell composite nano-adsorbent for fluoride removal from drinking water  

Science.gov (United States)

An adsorbent for fluoride removal from drinking water was prepared by coating Fe-Ti bimetallic oxide on magnetic Fe3O4 particles by co-precipitation. The adsorbent was a nanosized composite with a core-shell structure comprising a magnetic Fe3O4 core of 10-20 nm in diameter and an amorphous adsorbent shell of several nanometer thickness. The synthesis parameters were optimized to give high adsorption capacity and high magnetization. The optimized mass ratio of the Fe-Ti bimetallic oxide shell to Fe3O4 core was 2.72. The adsorption isotherm was well fitted with the Langmuir isotherm and the saturation adsorption capacity 57.22 mg/g adsorbent. Adsorption was fast and reached equilibrium within 2 min. The nano-adsorbent was superparamagnetic with a saturation magnetization of 18.4 emu/g, which allowed rapid separation of the adsorbent from the water solution by an external magnet.

Zhang, Chang; Chen, Lin; Wang, Ting-Jie; Su, Chao-Li; Jin, Yong

2014-10-01

48

Effect of potassium fluoride in electrolytic solution on the structure and properties of microarc oxidation coatings on magnesium alloy  

Science.gov (United States)

Oxide coatings were produced on AM60B magnesium alloy substrate making use of microarc oxidation (MAO) technique. The effect of KF addition in the Na 2SiO 3-KOH electrolytic solution on the microarc oxidation process and the structure, composition, and properties of the oxide coatings was investigated. It was found that the addition of KF into the Na 2SiO 3-KOH electrolytic solution caused increase in the electrolyte conductivity and decrease in the work voltage and final voltage in the MAO process. Subsequently, the pore diameter and surface roughness of the microarc oxidation coating were decreased by the addition of KF, while the coating compactness was increased. At the same time, the phase compositions of the coatings also varied after the addition of KF in the electrolytic solution, owing to the participation of KF in the reaction and its incorporation into the oxide coating. Moreover, the coating formed in the electrolytic solution with KF had a higher surface hardness and better wear-resistance than that formed in the solution without KF, which was attributed to the changes in the spark discharge characteristics and the compositions and structures of the oxide coatings after the addition of KF.

Liang, Jun; Guo, Baogang; Tian, Jun; Liu, Huiwen; Zhou, Jinfang; Xu, Tao

2005-10-01

49

Extraction of uranium from sea water with the granular composite adsorbent by using the fixed bed  

International Nuclear Information System (INIS)

To clarify the technical problems existing in the extraction process of uranium from sea water, uranium was extracted from natural sea water, with the granulated C-Ti-OH composite adsorbent. The adsorption of uranium from sea water was carried out by using the fixed bed that had been designed in our laboratory. The uranium recovery from the sea water was 13.9 % in the adsorption process of 56sub(d). The adsorbed uranium was eluted from the adsorbent with 0.5 sub(N) NaHCO3-0.5 sub(N) Na2CO3 soln. at 700C. The elution recovery was 97.4 % after 35 h. The uranium contained in the eluate was concentrated in the anion exchange process to 20 times as much as in the eluate, and then 100 times in the solvent extraction process with oxine-chloroform and TOA- kerosene. About 0.7 g of yellow cake was prepared from natural sea water, and it was identified to be 2UO2.NH3.3H2O by X-ray diffraction method and X-ray fluorometry. (author)

50

Biocompatibility of Ir/Ti-oxide coatings: Interaction with platelets, endothelial and smooth muscle cells  

Science.gov (United States)

Applying surface coatings on a biomedical implant is a promising modification technique which can enhance the implant's biocompatibility via controlling blood constituents- or/and cell-surface interaction. In this study, the influence of composition of IrxTi1-x-oxide coatings (x = 0, 0.2, 0.4, 0.6, 0.8, 1) formed on a titanium (Ti) substrate on the responses of platelets, endothelial cells (ECs) and smooth muscle cells (SMCs) was investigated. The results showed that a significant decrease in platelet adhesion and activation was obtained on Ir0.2Ti0.8-oxide and Ir0.4Ti0.6-oxide coatings, rendering the surfaces more blood compatible, in comparison to the control (316L stainless steel, 316L-SS) and other coating compositions. Further, a substantial increase in the EC/SMC surface count ratio after 4 h of cell attachment to the Ir0.2Ti0.8-oxide and Ir0.4Ti0.6-oxide coatings, relative to the 316L-SS control and the other coating compositions, indicated high potential of these coatings for the enhancement of surface endothelialization. This indicates the capability of the corresponding coating compositions to promote EC proliferation on the surface, while inhibiting that of SMCs, which is important in cardiovascular stents applications.

Habibzadeh, Sajjad; Li, Ling; Omanovic, Sasha; Shum-Tim, Dominique; Davis, Elaine C.

2014-05-01

51

Preparation and properties of the aluminium-activated carbon composite adsorbent for extraction of uranium from sea water  

International Nuclear Information System (INIS)

The effects of the hydrolysis pH and temperature of aluminium chloride in the presence of activated carbon on the properties of the products were studied to clear the preparation conditions of the composite adsorbent (C-Al-OH) for the extraction of uranium from sea water. Aluminium contents of the adsorbent increased when the hydrolysis pH and the temperature became higher. The adsorptive capacity for uranium was closely related to the physical and chemical properties of the adsorbent: the capacity increased in proportion to the mean pore size and the quantity of acid group, which was determined as alkaline consumption, whereas the capacity was inversely proportional to the specific surface area of the adsorbent. Most of the adsorbent was amorphous in X-ray diffraction pattern. Several adsorbents, which showed crystallinity in X-ray diffraction pattern, showed their low adsorptive capacity for uranium. The Freundlich's relationship was observed between the concentration and the capacity of uranium. Uranium uptake from natural sea water by the adsorbent was found to be 160-280 ?g/g-adsorbent after 30 days stirring. (auth.)

52

Novel adsorbent for DNA adsorption: Fe(3+)-attached sporopollenin particles embedded composite cryogels.  

Science.gov (United States)

The aim of this study is to prepare supermacroporous cryogels embedded with Fe(3+)-attached sporopollenin particles (Fe(3++)-ASPs) having large surface area for high DNA adsorption capacity. Supermacroporous poly(2-hydroxyethyl methacrylate) (PHEMA)-based monolithic cryogel column embedded with Fe3+(+)-ASPs was prepared by radical cryo-copolymerization of 2-hydroxyethyl methacrylate (HEMA) with N,N´-methylene- bis-acrylamide (MBAAm) as cross-linker directly in a plastic syringe for DNA adsorption studies. Firstly, Fe3+(+) ions were attached to the sporopollenin particles (SPs), then the supermacroporous PHEMA cryogel with embedded Fe(3++)-ASPs was produced by free radical polymerization using N,N,N´, N´-Tetramethylethylenediamine (TEMED) and ammonium persulfate (APS) as initiator/activator pair in an ice bath. Optimum conditions of adsorption experiments were performed at pH 6.0 (0.02 M Tris buffer containing 0.2 M NaCl), with flow rate of 0.5 mL/min, and at 5°C. The maximum amount of DNA adsorption from aqueous solution was very high (109 mg/g SPs) with initial concentration of 3 mg/mL. It was observed that DNA could be repeatedly adsorbed and desorbed with this composite cryogel without significant loss of adsorption capacity. As a result, higher amounts of DNA adsorbed these composite cryogels are expected to be good candidate for achieving higher removal of anti-DNA antibodies from systemic lupus erythematosus (SLE) patients plasma. PMID:23305206

Ceylan, ?eyda; Odaba??, Mehmet

2013-12-01

53

Polymer composite adsorbents using particles of molecularly imprinted polymers or aluminium oxide nanoparticles for treatment of arsenic contaminated waters.  

Science.gov (United States)

Removal of As(V) by adsorption from water solutions was studied using three different synthetic adsorbents. The adsorbents, (a) aluminium nanoparticles (Alu-NPs, sulphate and phosphate) affected arsenic removal for Alu-cryo more than for MIP-cryo. Both composites still adsorbed well in the presence of counter-ions (copper and zinc) present at low concentrations (?g/l). The unchanged and selective adsorption in realistic water observed for MIP-cryo was concluded to be due to a successful imprinting, here controlled using a non-imprinted polymer (NIP). A development of MIP-cryo is needed, considering its low adsorption capacity. PMID:22687522

Önnby, L; Pakade, V; Mattiasson, B; Kirsebom, H

2012-09-01

54

A Comparative Study of Agarose-Nickel prototype Composite Adsorbent and Commercial Streamline DEAE Adsorbent: Physical and Hydrodynamical Assessments  

Directory of Open Access Journals (Sweden)

Full Text Available Expanded bed adsorption (EBA is an integration technology for capturing target bioproducts directly from unclarified feedstock, designing and applying a good adsorbent affects its performance. In present work, a novel matrix has been developed for expanded bed adsorption process. The prepared matrix was manufactured using water-in-oil emulsification method. Desirable adsorbents tend to be of small size, high density as well as high porosity. Here, the prepared matrices had regular spherical shape, wet density of 1.95, followed logarithmic normal size distribution within the range of 50-200 µm, mean diameter of 126.4 µm, and 91.93% prosily. The Richardson-Zaki equation expressed the bed expansion and operation flow rate for the prepared matrix and Streamline DEAE. In addition, the theoretical prediction of correlation parameters (Ut and n was also measured. To characterize the hydrodynamic properties in the expanded bed, the residence time distribution method was used. The physical and hydrodynamic properties of the fabricated matrix were studied and compared with those of the commercial Streamline DEAE matrix. The results indicated that the prepared matrices showed good expansion and stability in the bed, and are thus suitable for expanded bed applications.

F. Asghari

2012-01-01

55

Leach resistant cesium and strontium-bearing wasteforms from hexagonal tungsten bronze-polyacrylonitrile composite adsorbers  

International Nuclear Information System (INIS)

Immobilization of adsorbed Cs+ and Sr2+ on a molybdenum-doped, hexagonal tungsten bronze (HTB)-polyacrylonitrile (PAN) composite adsorbent can be achieved by heating in air at temperatures in the range 600 - 1200 deg. C. Thermal treatment of the parent composite material at 800 - 1000 deg. C undergoes a ca. 60% reduction in volume and retains its spherical morphology. For materials prepared at 800 - 1200 deg. C the full complement of Cs+ and the majority of Sr2+ partition into HTB phases (A?0.16-0.3MO3; A = Cs, Sr, Na; M = Mo,W), along with sodium cations. The presence of high concentrations of Na+ relative to either Cs+ or Sr2+ does not appear to interfere with the formation of the HTB phase. The fraction (f) of Cs+ and Sr2+ leached from the tungstate phase assemblages is better or comparable with cesium hollandite (Cs0.8Ba0.4Ti8O18; f = ca. 8 x 10-5; rate = -4 g m-2 d-1) and strontium titanate (SrTiO3; f = 3.1 x 10-3; rate 2.63 x 10-4 g m-2 day-1), respectively, using a modified PCT test. Furthermore, where aggressive leaching conditions are employed (0.1M HNO3; 150 deg. C; 4 days), the tungstate phase assemblages display leach resistance orders of magnitude better than the reference phases (Cs+ an the reference phases (Cs+ - f = ca. 5 x 10-3; rate = ca. 1.4 x 10-3 g m-2 day-1; Sr2+ - f = ca. 8 x 10-2; rate = ca. 2.5 x 10-2 g m-2 day-1). (author)

56

Bacteriophage PRD1 and silica colloid transport and recovery in an iron oxide-coated sand aquifer  

Science.gov (United States)

Bacteriophage PRD1 and silica colloids were co-injected into sewage- contaminated and uncontaminated zones of an iron oxide-coated sand aquifer on Cape Cod, MA, and their transport was monitored over distances up to 6 m in three arrays. After deposition, the attached PRD1 and silica colloids were mobilized by three different chemical perturbations (elevated pH, anionic surfactant, and reductant). PRD1 and silica colloids experienced less attenuation in the contaminated zone where adsorbed organic matter and phosphate may be hindering attachment of PRD1 and silica colloids to the iron oxide coatings. The PRD1 collision efficiencies agree well with collision efficiencies predicted by assuming favorable PRD1 deposition on iron oxide coatings for which the surface area coverage was measured by microprobe analysis of sediment thin sections. ?? potentials of the PRD1, silica colloids, and aquifer grains corroborated the transport results, indicating that electrostatic forces dominated the attachment of PRD1 and silica colloids. Elevated pH was the chemical perturbation most effective at mobilizing the attached PRD1 and silica colloids. Elevated surfactant concentration mobilized the attached PRD1 and silica colloids more effectively in the contaminated zone than in the uncontaminated zone.Bacteriophage PRD1 and silica colloids were co-injected into sewage-contaminated and uncontaminated zones of an iron oxide-coated sand aquifer on Cape Cod, MA, and their transport was monitored over distances up to 6 m in three arrays. After deposition, the attached PRD1 and silica colloids were mobilized by three different chemical perturbations (elevated pH, anionic surfactant, and reductant). PRD1 and silica colloids experienced less attenuation in the contaminated zone where adsorbed organic matter and phosphate may be hindering attachment of PRD1 and silica colloids to the iron oxide coatings. The PRD1 collision efficiencies agree well with collision efficiencies predicted by assuming favorable PRD1 deposition on iron oxide coatings for which the surface area coverage was measured by microprobe analysis of sediment thin sections. ?? potentials of the PRD1, silica colloids, and aquifer grains corroborated the transport results, indicating that electrostatic forces dominated the attachment of PRD1 and silica colloids. Elevated pH was the chemical perturbation most effective at mobilizing the attached PRD1 and silica colloids. Elevated surfactant concentration mobilized the attached PRD1 and silica colloids more effectively in the contaminated zone than in the uncontaminated zone.

Ryan, J. N.; Elimelech, M.; Ard, R. A.; Harvey, R. W.; Johnson, P. R.

1999-01-01

57

Thermal conductivity of oxide coating on Zircaloy-2  

International Nuclear Information System (INIS)

Zircaloy-2 is being extensively used as a cladding material in aqueous nuclear power plants. During its operation, the clad becomes coated with an oxide layer. This layer could alter its heat transfer characteristics thus affecting some of the reactor operating parameters. The authors report the experimental determination of the thermal conductivity of the oxide coating employing a simple, reliable and direct method. (Auth.)

58

A technique for investigating the interface between the base material and the oxide coating in the scanning electron microscope  

International Nuclear Information System (INIS)

The preparation technique described renders the oxide coating/base material boundary region accessible to SEM investigation. The investigation provides information on morphology and chemical composition. Oxidation mechanisms can be studied in a variety of materials, whereby even the starting structure can be revealed. Information is gained concerning adhesion mechanisms. The influence of surface quality and oxidation conditions on the oxidation can be shown. The investigation of corrosion processes is also possible. (orig.)

59

Hybrid magnetic amphiphilic composites based on carbon nanotube/nanofibers and layered silicates fragments as efficient adsorbent for ethynilestradiol.  

Science.gov (United States)

In this work, hybrid magnetic amphiphilic composites were prepared by the catalytic growth of carbon nanotubes (CNTs) and nanofibers CNF on layered silicates fragments. SEM, TEM, Raman, XRD, Mössbauer, TG/DTA showed that CVD with CH(4) at 800°C produced CNF and magnetic Fe cores fixed on the surface of microfragments of silicates layers. Due to the amphiphilic character, the composites can be easily dispersed in water and efficiently adsorb hydrophobic contaminant molecules. For example, the composites showed remarkable adsorption capacities for the hormone ethinylestradiol, e.g. 2-4 mg m(-2), compared to ca. 0.1 mg m(-2) obtained for high surface area activated carbon and multiwall CNT. These results are discussed in terms of a high hydrophobic exposed surface area of the CNT and CNF fixed on the layered silicates fragments surface. Moreover, the composites can be easily removed from water by a simple magnetic separation process. PMID:22608147

Purceno, Aluir D; Teixeira, Ana Paula C; de Souza, Nubia Janaína; Fernandez-Outon, Luis E; Ardisson, José D; Lago, Rochel M

2012-08-01

60

Tin oxide coating on molybdenum oxide nanowires for high performance supercapacitor devices  

International Nuclear Information System (INIS)

Tin oxide coated molybdenum oxide nanowires (SnO2/MoO3) are synthesized by a combination of hydrothermal and wet chemical routes. The electrochemical capacitance properties of the SnO2/MoO3 core shell composite nanowires are measured by cyclic voltammetry (CV) and galvanostatic charge–discharge method in 1 M Na2SO4 aqueous solutions. The results showed that specific capacitance of SnO2/MoO3 core shell composite nanowires is 295 F g?1, which is much higher than the specific capacitance of pure individual MoO3 (69 F g?1) and SnO2 (96.6 F g?1). Moreover the synthesized core shell composite nanowires has also exhibited excellent long-term cycling stability (only 3% loss of its initial specific capacitance after 1000 cycles) which may lead to its multifarious usage in high-performance energy storage devices for future potential applications.

 
 
 
 
61

Municipal sludge-industrial sludge composite desulfurization adsorbents: synergy enhancing the catalytic properties.  

Science.gov (United States)

Mixtures of sewage sludge, waste oil sludge, and metal oil sludge were prepared and carbonized at 950 degrees C in an inert atmosphere. Dynamic adsorption of H2S was measured on the materials obtained, and the breakthrough capacity was calculated. The initial and exhausted adsorbents after the breakthrough tests were characterized using sorption of nitrogen, thermal analysis, and XRF, XRD, and surface pH measurements. Mixing sludges leads to very high capacity adsorbents on which hydrogen sulfide is oxidized to elemental sulfur. Although the micropore volume of the adsorbents obtained is not high, their high volume of mesopores contributes significantly to reactive adsorption and provides space to store the oxidation products. The H2S breakthrough capacity on the new materials reaches 10 wt %. These adsorbents work until all active pores are filled and the catalytic centers are exhausted. The reason for such high capacity is in the formation of catalytically active mineral like phases during pyrolysis in the presence of nitrogen and carbon. This highly dispersed phase provides basicity and catalytic centers for hydrogen sulfide dissociation and its oxidation to sulfur. PMID:16749709

Bandosz, Teresa J; Block, Karin

2006-05-15

62

Antibacterial activity of zinc oxide-coated nanoporous alumina  

International Nuclear Information System (INIS)

Highlights: ? Atomic layer deposition was used to deposit ZnO on nanoporous alumina membranes. ? Scanning electron microscopy showed continuous coatings of zinc oxide nanocrystals. ? Activity against B. subtilis, E. coli, S. aureus, and S. epidermidis was shown. - Abstract: Nanoporous alumina membranes, also known as anodized aluminum oxide membranes, are being investigated for use in treatment of burn injuries and other skin wounds. In this study, atomic layer deposition was used for coating the surfaces of nanoporous alumina membranes with zinc oxide. Agar diffusion assays were used to show activity of zinc oxide-coated nanoporous alumina membranes against several bacteria found on the skin surface, including Bacillus subtilis, Escherichia coli, Staphylococcus aureus, and Staphylococcus epidermidis. On the other hand, zinc oxide-coated nanoporous alumina membranes did not show activity against Pseudomonas aeruginosa, Enterococcus faecalis, and Candida albicans. These results suggest that zinc oxide-coated nanoporous alumina membranes have activity against some Gram-positive and Gram-negative bacteria that are associated with skin colonization and skin infection.

63

The effects of chemical composition of adsorbed molecular layers on lithium electrode/polymer electrolyte interface stabilization  

Science.gov (United States)

Previous work in our laboratory has shown that the adsorption of self-assembled molecular layers on a polymer electrolyte surface can make the interface between the electrolyte and a lithium metal electrode more stable and can hinder the growth of the type of passivation layer that inhibits ion movement between the electrode and electrolyte. This work is concerned with the effect that the molecular composition of the adsorbed layer has on interface stability. Several compounds of the form R?(CH 2CH 2O)?H have been found to adsorb on the surface of the polymer electrolyte and stabilize the interface. It was found that the R group could be a long, straight hydrocarbon tail capable of forming an ordered self-assembled structure or a branched hydrocarbon or a siloxane with bulky hydrocarbon groups that form a brush-type structure. Molecules of the form R?OH and R?COOH, where R was a long, straight-chain hydrocarbon, would adsorb but appeared to have much disorder in their hydrocarbon chains. It is proposed that this disorder results from a low adsorption density that results in regions where the lithium metal can come in direct contact with the polymer electrolyte causing reactions that promote interface destabilization.

Le Granvalet-Mancini, Maryline; Teeters, Dale

64

Adsorption characteristics of As(III) from aqueous solution on iron oxide coated cement (IOCC)  

International Nuclear Information System (INIS)

Contamination of potable groundwater with arsenic is a serious health hazard, which calls for proper treatment before its use as drinking water. The objective of the present study is to assess the effectiveness of iron oxide coated cement (IOCC) for As(III) adsorption from aqueous solution. Batch studies were conducted to study As(III) adsorption onto IOCC at ambient temperature as a function of adsorbent dose, pH, contact time, initial arsenic concentration and temperature. Kinetics reveal that the uptake of As(III) ion is very rapid and most of fixation occurs within the first 20 min of contact. The pseudo-second order rate equation successfully described the adsorption kinetics. Langmuir, Freundlich, Redlich-Peterson (R-P), and Dubinin-Radushkevich (D-R) models were used to describe the adsorption isotherms at different initial As(III) concentrations and at 30 g l-1 fixed adsorbent dose. The maximum adsorption capacity of IOCC for As(III) determined from the Langmuir isotherm was 0.69 mg g-1. The mean free energy of adsorption (E) calculated from the D-R isotherm was found to be 2.86 kJ mol-1 which suggests physisorption. Thermodynamic parameters indicate an exothermic nature of adsorption and a spontaneous and favourable process. The results suggest that IOCC can be suitably used for As(III) removal from aqueous solutions

65

As(V) adsorption onto nanoporous titania adsorbents (NTAs): effects of solution composition.  

Science.gov (United States)

This study has focused on developing two nanoporous titania adsorbents (NTA) to enhance removal efficiency of adsorption process for As(V) by characterizing the effects of pH and phosphate concentration on their sorption capacities and behaviors. One type of adsorbent is a mesoporous titania (MT) solid phase and the other is group of a highly ordered mesoporous silica solids (SBA-15) that can incorporate different levels of reactive titania sorption sites. Microscopic analysis showed that Ti((25))-SBA-15 (Ti/SBA=0.25 g/g) had titania nanostructured mesopores that do not rupture the highly ordered hexagonal silica framework. However, MT has disordered, wormhole-like mesopores that are caused by interparticle porosity. Adsorption experiments showed that Ti((25))-SBA-15 had a greater sorption capacity for As(V) than did Ti((15))-SBA-15 or Ti((35))-SBA-15 and the amount of As(V) adsorbed generally decreased as pH increased. Higher removal of As(V) was observed with Ti((25))-SBA-15 than with MT at pH 4, but MT had higher removals at higher pH (7, 9.5), even though MT has a lower specific surface area. However, in the presence of phosphate, MT showed higher removal of As(V) at low pH rather than did Ti((25))-SBA-15. As expected, the NTAs showed very fast sorption kinetics, but they followed a bi-phasic sorption pattern. PMID:22727482

Han, Dong Suk; Batchelor, Bill; Park, Sung Hyuk; Abdel-Wahab, Ahmed

2012-08-30

66

Preparation of composites immobilizing highly selective adsorbents and their application to the separation of nuclides  

International Nuclear Information System (INIS)

Radionuclides in high-level liquid waste are classified into four groups such as transuranic elements (TRU) group, technetium - platinum group, strontium - cesium group, and others group. Cesium showed high adsorption selectivity to AMP [(NH4)3PO412MoO33H2O], AWP [(NH4)3PO412WO33H2O], and KNiFC(K2-xNix/2[NiFe(CN)6]nH2O). These inorganic ion exchangers with selectivity of cesium are possible to be supported by porous materials and to be immobilized by polymer. Some examples (AMP/Al2O3, AMP/alginate, and KNiFC/zeolite) are shown in this paper. KCuFC/alginate can adsorb Pd into KCuFC, Ru into alginate, but can not adsorb Rh. Accordingly, platinum metals (Pd, Ru and Rh) are separated by it. Pd, Ru and Rh in their mixed solution are mutually separated by using Cyanex 302/alginate and chromatography. Eu and Am adsorbed by Cyanex 301-alginate acid gel microcapsule were separated by gradient elution. Then, 98.8% of Eu and 91.3% of Am were eluted at pH 2 and pH 1, respectively. (S.Y.)

67

Novel nanosized adsorbing sulfur composite cathode materials for the advanced secondary lithium batteries  

Energy Technology Data Exchange (ETDEWEB)

A novel conductive sulfur-containing nanocomposite cathode material was synthesized by heating the mixture of sublimed sulfur and multi-walled carbon nanotubes (MWNTs) in certain conditions. The cathode with MWNTs-sulfur nanocomposite (MSN) material shows the improvement of not only the charge-discharge capacity but also cycle durability. From the results, it is confirmed that the MWNTs shows a vital role on adsorbing sublimed sulfur and the polysulfides within the cathode and is an excellent electric conductor for the lithium-sulfur rechargeable system. It can effectively prevent the shuttle behavior of the lithium-sulfur battery. (authors)

Zheng, W.; Liu, Y.W.; Zhang, C.F. [Department of Applied Chemistry, Harbin Institute of Technology, Harbin 150001 (China); Jiangmen JJJ Battery Co., Ltd, Jiangmen 529000 (China); Hu, X.G. [Department of Applied Chemistry, Harbin Institute of Technology, Harbin 150001 (China)

2006-01-05

68

Novel nanosized adsorbing sulfur composite cathode materials for the advanced secondary lithium batteries  

International Nuclear Information System (INIS)

A novel conductive sulfur-containing nanocomposite cathode material was synthesized by heating the mixture of sublimed sulfur and multi-walled carbon nanotubes (MWNTs) in certain conditions. The cathode with MWNTs-sulfur nanocomposite (MSN) material shows the improvement of not only the charge-discharge capacity but also cycle durability. From the results, it is confirmed that the MWNTs shows a vital role on adsorbing sublimed sulfur and the polysulfides within the cathode and is an excellent electric conductor for the lithium-sulfur rechargeable system. It can effectively prevent the shuttle behavior of the lithium-sulfur battery

69

Electrochemical properties of inorganic nanoporous oxide coated electrodes  

Science.gov (United States)

The ability to produce clean water and produce and store clean energy is essential to society. Hence, technologies that facilitate clean energy and clean water are of great importance. This study focused on utilizing nanoporous insulating oxide materials to alter the chemistry at the electrode/electrolyte interface to improve the performance of a number of clean energy and clean water technologies. Here we have shown that applying a thin-film of SiO2 nanoparticles to an electrochemical capacitor electrode can increase the energy storage capacity by up to 50% at high power ratings. We have developed a geometric model to describe the coating of the porous electrode to explain the increased performance at high power ratings. We have also shown that the coated electrochemical capacitor exhibits a higher capacitance when normalized to BET surface area, suggesting that the coated surface is behaving fundamentally differently than the uncoated surface. We attribute the increase in capacitance to the inherent surface potential of the oxide coating and have shown that if we alter the surface potential of the oxide, we can in turn alter the electrochemical capacitance. In addition, we have determined that when used in capacitive deionization systems, these coatings can increase ion removal and accelerate regeneration, allowing for higher efficiency and less waste water. We have demonstrated that a nanoporous oxide coating can increase the gas production rate and lower the overpotential of the hydrogen evolution reaction via water electrolysis on both stainless steel and carbon electrodes. In addition, this work presents data on utilizing nanoporous oxide coatings on Li-Ion battery cathodes to improve high temperature capacity fade. We also introduce a novel thin-film battery/electrochemical capacitor hybrid device, which can improve the performance of simple thin-film batteries.

Leonard, Kevin C.

70

Metal oxide-coated anodes in wastewater treatment.  

Science.gov (United States)

Electrochemical oxidation is an effective wastewater treatment method. Metal oxide-coated substrates are commonly used as anodes in this process. This article compiles the developments in the fabrication, application, and performance of metal oxide anodes in wastewater treatment. It summarizes the preparative methods and mechanism of oxidation of organics on the metal oxide anodes. The discussion is focused on the application of SnO2, PbO2, IrO2, and RuO2 metal oxide anodes and their effectiveness in wastewater treatment process. PMID:24293296

Subba Rao, Anantha N; Venkatarangaiah, Venkatesha T

2014-03-01

71

Enhancement of phosphorus sorption onto light expanded clay aggregates by means of aluminum and iron oxide coatings.  

Science.gov (United States)

Phosphorus (P) loading from non-point or point sources increases the eutrophication risk of natural waters. The functioning of constructed wetlands (CWs) used as natural water treatment systems can be improved by means of additional materials adsorbing soluble P. In this study, light expanded clay aggregates (LECA) and LECA coated with aluminum (Al) oxide (Al-LECA) or iron (Fe) oxide (Fe-LECA) were tested for their efficiency as P sorbents in the pH range 3-8. The oxide coatings duplicated the actual sorption capacity calculated from the sorption isotherms at the P concentration in the equilibrium solution of 20 ?g L(-1), assumed to be the allowable P level in purified water. In the oxide-coated LECAs the sorption was fast and followed both the first- and second-order Lagergren kinetic models, suggesting that the formation of a binuclear surface complex was feasible. In LECA, sorption was markedly slower and followed the first-order kinetic model, indicating that retention occurred through a monodentate attachment. These findings were in harmony with the degree of P saturation (DPS) of the sorbent surfaces at the highest P addition level (200 ?g L(-1)), DPS being decisively higher for LECA than for the oxide-coated sorbents. Accordingly, at higher pH values the competition by hydroxyl ions diminished the sorption in LECA relatively more than that in the coated sorbents. In agreement with the acidity of Al(3+) being 100 times lower than that of Fe(3+), at elevated pH the sorption by Al-LECA proved to be less reversible than that by Fe-LECA. The results provide evidence that in CWs Al-coated sorbents are superior to Fe-coated ones that are also redox-sensitive and may lose their sorption properties in anoxic conditions. PMID:23866174

Yaghi, Nader; Hartikainen, Helinä

2013-11-01

72

Preparation of organic-inorganic composite adsorbent beads for removal of radionuclides and heavy metal ions  

International Nuclear Information System (INIS)

Composite ion exchanger beads were prepared to remove the strontium and silver ions in acidic solution. Potassium titanate and nickelferrocyanate powder, which are acid resistant inorganic ion exchangers were synthesized and then mixed with polyacrylonitrile (PAN) binder to form a PAN-potassium titanate and a PAN-nickelferrocyanate composite ion exchanger beads. Spherical composite beads could be obtained by adjusting the viscosities of the composite dope in the range of 700-1000 cP. The composite beads porosities such as macropore volume and pore size were increased in proportion to the contents of PVP (polyvinylpyrrolidone) which was used as the porosity modifying chemical. The synthesized composite ion exchangers were evaluated on their adsorption characteristics for the Ag+ and Sr2+ ion solutions of pH 2. (author)

73

Fabrication of electrically conductive metal oxide coatings by reactive ion plating  

International Nuclear Information System (INIS)

Electrically conductive metal oxide (ceramic) coatings produced by reactive ion plating are being investigated at USA-CERL for potential application in cathodic protection systems. Ceramic materials are advantageous because of their very low dissolution rates (typically less than 1 g/A/yr in 3.5% NaCl solution) and ease of fabrication. Among the ceramic anode materials currently under investigation are two systems: (1) a mixture of titanium oxide and ruthenium oxide and (2) a mixture of titanium oxides ''doped'' with niobium, each ion plated on niobium substrates. The mixed oxide coatings were fabricated by a reactive ion plating process involving oxygen and dual electron beam evaporation sources. An enhanced plasma was used to increase reactivity. X-ray diffraction, scanning electron microscopy, and energy dispersive x-ray spectroscopy have been used for characterization of the microstructure, crystallography, and elemental composition of the coating

74

Hydrophilicity of titanium oxide coatings with the addition of silica  

International Nuclear Information System (INIS)

This work investigated hydrophilicity between titanium oxide coatings with and without addition of silica. A sol of titania and silica was prepared for sol-gel coating. The sol of titanium oxide is aqueous, and the mixed sol is transparent with a pH value of 8.0. Coating was prepared by spraying mixed sol over a heated substrate. The titanium oxide sol was prepared by using an inorganic titanium salt. A silica sol was then added to titanium oxide sol obtain the mixed sol. Thickness of the coatings were between 20 and 80 nm. The sols were characterized by IR spectroscopy. AFM was used to investigate the coating surface structure and roughness. The crystalline size of coating surface for the mixed oxides was little greater than for the pure titanium oxide. The crystalline phase was investigated using X-ray diffraction. The hydrophilicity of coatings was studied with UV and sunlight exposure and by measurement of contact angle change of droplets of water. Through the investigation of change of contact angle and water droplets on the surface after UV exposure and sunlight radiation, it can be concluded that hydrophilicity of mixed coatings with low temperature heat-treatment of titanium oxide and silica are much better than a pure titanium oxide coating. This effect makes for an improved self-cleaning coating

75

Molecular and isotopic compositions of gases adsorbed to near surface sediments at Starunia palaeontological site and vicinity (Carpathian region, Ukraine  

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Full Text Available The near-surface geochemical survey of gases desorbed from sediment samples was carried out in the area of an abandoned ozokerite mine in Starunia, where remnants of mammoth and three woolly rhinoceroses and one almost completely preserved rhinoceros carcass were discovered in 1907 and 1929. Numerous hydrocarbon seeps (gas and oil "eyes" occur on the surface of the study area. Analyses of molecular and stable carbon isotope compositions of adsorbed gases were carried out in two variants. The first included sampling of cuttings from 30 auger boreholes at depths of 4.8, 5.6 and 6.4 m. In total, 88 samples were collected. In the second variant core samples were collected from 17 selected boreholes. In total, 78 samples were taken from various depths to 12 m. The results of molecular composition analyses of desorbed gases indicated high saturation of near-surface sediments with the oil. The highest concentrations of alkanes were detected in Miocene strata. Hydrocarbon migration from deep accumulations to the surface was relatively fast and proceeded along the faults, fractures and cracks. In the near-surface zone hydrocarbons were subjected to oxidation and dehydrogenation, which resulted in generation of unsaturated hydrocarbons and hydrogen. These processes were most intensive in the Pleistocene sediments and in the mine dumps. Increased concentrations of hydrogen may also originate from water radiolysis in the presence of hydrocarbons. Concentrations of carbon dioxide in the adsorbed gases show the higher values in comparison with the analysed gaseous compounds. However, a slight increase in CO2 concentration was detected in the mine dump, which may indicate conditions more favourable for hydrocarbon oxidation. Carbon dioxide from the analysed adsorbed gases is of thermogenic origin. Occasionally, insignificant influence of secondary hydrocarbon oxidation and/or Quaternary organic matter can be observed. Concentrations of alkanes, alkenes and carbon dioxide in the gas derived from desorption of rock samples are lower and the concentration of hydrogen is higher than those measured in free gases. This indicates that additional effects from recent (e.g. microbial processes are absent.

Marek DZIENIEWICZ

2009-01-01

76

Carbon and functionalized graphene oxide coated vanadium oxide electrodes for lithium ion batteries  

Science.gov (United States)

Carbon- and graphene oxide-coated vanadium oxide nanomaterials were synthesized from a VOSO4 sol using a hydrothermal method to prepare electrodes for lithium ion batteries. The synthesized materials were characterized using x-ray diffraction, scanning electron microscopy and transmission electron microscopy. Electrochemical results show that graphene oxide coated vanadium oxide electrodes have higher capacity than the carbon coated ones.

Reddy Channu, V. S.; Ravichandran, D.; Rambabu, B.; Holze, Rudolf

2014-06-01

77

Irradiation-induced dehydrogenation of a crystalline ZrH1.85 system with an oxide coating  

International Nuclear Information System (INIS)

With the help of methods of X-ray diffraction analysis and thermal neutron incoherent scattering the radiation resistance of a crystalline system ZrH1.85 with an oxide coating is studied. It is revealed that after the action of powerful fast neutron and hard ?-radiation fluxes in a BN-600 reactor core at the temperature of ? 400 deg C an effect of partial loss of hydrogen in zirconium hydride takes place. The effect of radiation-induced dehydrogenation is shown to be conditioned by the composition of the coating

78

Conductivity of copper phthalocyanine-polystyrene composite films in the presence of adsorbed oxygen  

Science.gov (United States)

The electrical conductivity and adsorption-resistive response to nitrogen dioxide of composite films containing copper phthalocyanine nanoparticles dispersed into the polystyrene matrix are investigated experimentally. The results are analyzed using the two-level model of hopping conductivity. The contributions to the conductivity from intrinsic and impurity localization centers are singled out, and the concentrations of the localization centers in copper phthalocyanines free of impurities as well as the electron localization radii in impurity and intrinsic states are determined.

Pochtennyi, A. E.; Misevich, A. V.; Dolgii, V. K.

2014-09-01

79

Novel low density granular adsorbents - properties of a composite matrix from zeolitisation of vermiculite.  

Science.gov (United States)

This paper reports the preparation and properties of a new low density granular absorbent material based on a zeolite/vermiculite composite. The composite prepared addresses a number of important issues relating to the use of zeolites in environmental and waste management applications. The material prepared has large particle size due to binderless adhesion of zeolite crystals within the protective lamellar matrix provided by the vermiculite granule. Additionally, the porous nature of new material ensures that it outperforms natural zeolite grains in ion-exchange tests. The material was shown to have a low bulk density (0.75 g cm(-3)) adding the benefit that the majority of grains float on water for over 15 h. The conclusion of the study is that the use of composite matrices enable the preparation of materials which show the physical properties of the host, (e.g., granular and low density), whilst maintaining the powder-like properties (e.g., high ion-exchange and small crystal size) of the active component. The resulting material can be easily handled and separated from aqueous waste streams using either flotation or exploiting its granular nature. PMID:17368511

Johnson, Christopher D; Worrall, Fred

2007-06-01

80

CuFe2O4/activated carbon composite: a novel magnetic adsorbent for the removal of acid orange II and catalytic regeneration.  

Science.gov (United States)

CuFe2O4/activated carbon magnetic adsorbents, which combined the adsorption features of activated carbon with the magnetic and the excellent catalytic properties of powdered CuFe2O4, were developed using a simple chemical coprecipitation procedure. The prepared magnetic composites can be used to adsorb acid orange II (AO7) in water and subsequently, easily be separated from the medium by a magnetic technique. CuFe2O4/activated carbon magnetic adsorbents with mass ratio of 1:1, 1:1.5 and 1:2 were prepared. Magnetization measurements, BET surface area measurements, powder XRD and SEM were used to characterize the prepared adsorbents. The results indicate that the magnetic phase present is spinel copper ferrite and the presence of CuFe2O4 did not significantly affect the surface area and pore structure of the activated carbon. The adsorption kinetics and adsorption isotherm of acid orange II (AO7) onto the composites at pH 5.2 also showed that the presence of CuFe2O4 did not affect the adsorption capacity of the activated carbon. The thermal decomposition of AO7 adsorbed on the activated carbon and the composite was investigated by in situ FTIR, respectively. The results suggest that the composite has much higher catalytic activity than that of activated carbon, attributed to the presence of CuFe2O4. The variation of the adsorption capacity of the composites after several adsorption-regeneration cycles has also been studied. PMID:17397903

Zhang, Gaosheng; Qu, Jiuhui; Liu, Huijuan; Cooper, Adrienne T; Wu, Rongcheng

2007-06-01

 
 
 
 
81

EIS study of nano crystalline Ni-cerium oxide coating electrodeposition mechanism  

Energy Technology Data Exchange (ETDEWEB)

Research highlights: > In this study a new procedure was used for electrodeposition of Ni-cerium oxide amorphous-nano crystalline composite coatings. The innovation of this method is that the metal and oxides are deposited simultaneously on the samples from the plating bath solution containing Ni ions and Ce ions with no powder added. - Abstract: In this study a novel procedure was used for the electrodeposition of Ni-cerium oxide nano crystalline composite coatings. The novelty of this method lies in the fact that the metal and the oxide are both deposited simultaneously on the substrate, directly from the plating bath containing Ni and Ce ions with no oxide powder addition. Electrochemical impedance spectroscopy (EIS), scanning electron microscopy (SEM), X-ray diffraction (XRD) and energy dispersive spectroscopy (EDS) were used to study the mechanisms of Ni-CeO{sub 2} nanocomposite coating deposition. The results indicated that the morphology of Ni-cerium oxide coatings varied based on the Ni:Ce ion ratio. When this ratio exceeds 100, sporadic distribution of cerium oxide in the Ni matrix occurred. On the other hand, when the aforementioned ratio was less than 100, it was found that Ni species were dispersed in a continuous film of cerium oxide. Furthermore, it was observed that Ni in Ni-cerium oxide composite coating was nanocrystalline, while cerium oxide was amorphous. Introduction of the cerium ions to the plating bath resulted in the reduction of the Ni grains average size.

Hasannejad, H. [Department of Materials Science and Engineering, Tarbiat Modares University, Tehran (Iran, Islamic Republic of); Shahrabi, T., E-mail: Tshahrabi34@modares.ac.ir [Department of Materials Science and Engineering, Tarbiat Modares University, Tehran (Iran, Islamic Republic of); Jafarian, M. [Department of Chemistry, K.N. Toosi University of Technology, P.O. Box 15875-4416, Tehran (Iran, Islamic Republic of); Rouhaghdam, A. Sabour [Department of Materials Science and Engineering, Tarbiat Modares University, Tehran (Iran, Islamic Republic of)

2011-02-03

82

EIS study of nano crystalline Ni-cerium oxide coating electrodeposition mechanism  

International Nuclear Information System (INIS)

Research highlights: ? In this study a new procedure was used for electrodeposition of Ni-cerium oxide amorphous-nano crystalline composite coatings. The innovation of this method is that the metal and oxides are deposited simultaneously on the samples from the plating bath solution containing Ni ions and Ce ions with no powder added. - Abstract: In this study a novel procedure was used for the electrodeposition of Ni-cerium oxide nano crystalline composite coatings. The novelty of this method lies in the fact that the metal and the oxide are both deposited simultaneously on the substrate, directly from the plating bath containing Ni and Ce ions with no oxide powder addition. Electrochemical impedance spectroscopy (EIS), scanning electron microscopy (SEM), X-ray diffraction (XRD) and energy dispersive spectroscopy (EDS) were used to study the mechanisms of Ni-CeO2 nanocomposite coating deposition. The results indicated that the morphology of Ni-cerium oxide coatings varied based on the Ni:Ce ion ratio. When this ratio exceeds 100, sporadic distribution of cerium oxide in the Ni matrix occurred. On the other hand, when the aforementioned ratio was less than 100, it was found that Ni species were dispersed in a continuous film of cerium oxide. Furthermore, it was observed that Ni in Ni-cerium oxide composite coating was nanocrystalline, while cerium oxide was amorphous. Introduction of the cerium ions to the plating bath resulted in the reduction of the Ni ath resulted in the reduction of the Ni grains average size.

83

Composite membranes modified with recognition-able nanobeads as potential adsorbers for purification of biological fluids.  

Science.gov (United States)

Therapeutic approaches in the clinical field require advanced properties for delivery or recognition of clinical species. The molecular imprinting method allows selective cavities to be inserted into a polymeric material built "around" a stamp molecule (template) through polymerization or phase inversion. This study focuses on the application of both methods in the realization of polymeric membranes with selective recognition and adsorption properties. Imprinted polymethacrylic acid (PMAA) particles, exhibiting specific binding sites for cholesterol molecule (template), were realized via precipitation polymerization in the shape of nanobeads and loaded in the bulk or on the surface of methylmethacrylate-acrylic acid P(MMA-co-AA) membranes obtained by the non-solvent induced phase separation (NIPS) technique. In this way, specific cavities were introduced into the membrane network to enhance and specialize uptake performances of the porous membranes taking advantage of the particle characteristics. Rebinding performances towards cholesterol in a physiological environment were tested showing very interesting results: the adsorption of cholesterol molecules from physiological solution was increased by using composite membrane-nanobead systems instead of control membranes (a quantitative increase of 14 mg of cholesterol per g of polymer matrix in respect of blank membrane was detected). The results obtained showed an improved performance of composite membranes, but also an unmodified behavior of loaded nanobeads (with respect to free ones) concerning the recognition capability in aqueous medium, which is the most difficult obstacle to overcome in molecular imprinting. The absolute rebinding capacity and the imprinting efficiency of membranes were in the range (and in some case higher) of other efficient systems, but the real improvement was that molecularly imprinted embranes showed an excellent recognition capacity in physiological medium instead of organic solvents. PMID:20799186

Silvestri, D; Cristallini, C; Borrelli, C; Barbani, N; Giusti, P; Ciardelli, G

2007-01-01

84

Removal of transition metal ions from aqueous solutions by adsorption onto a novel silica gel matrix composite adsorbent  

International Nuclear Information System (INIS)

This paper presented the synthesis of a novel composite adsorbent silica gel microspheres encapsulated with 5-sulfosalicylic acid functionalized polystyrene (SG-PS-azo-SSA). It was characterized by titration method, FT-IR (Fourier transform infrared spectrometer), SEM (scanning electron microscope), EDXAS (energy dispersive X-ray analysis system), etc. SG-PS-azo-SSA has been used to investigate the adsorption of Mn(II), Fe(III), Co(II), Ni(II), Zn(II), Cd(II), Hg(II), Pd(II), Cu(II), Ag(I) and Au(III) from aqueous solutions. The research results revealed that SG-PS-azo-SSA has the better adsorption capacity for Cu(II), Ag(I) and Au(III). Langmuir and Freundlich isotherm models were applied to analyze the experimental data and the adsorption of Cu(II), Ag(I) and Au(III) on SG-PS-azo-SSA fitted well to the Langmuir isotherm equation. The obtained maximum adsorption capacity for Cu(II), Ag(I), and Au(III) is 0.472 mmol/g, 0.822 mmol/g and 0.810 mmol/g, respectively. Thus, silica gel encapsulated by 5-sulfosalicyclic acid functionalized polystyrene (SG-PS-azo-SSA) is favorable and useful for the removal of Cu(II), Ag(I) and Au(III) metal ions.

85

Laccase immobilized on a PAN/adsorbents composite nanofibrous membrane for catechol treatment by a biocatalysis/adsorption process.  

Science.gov (United States)

The treatment of catechol via biocatalysis and adsorption with a commercial laccase immobilized on polyacrylonitrile/montmorillonite/graphene oxide (PAN/MMT/GO) composite nanofibers was evaluated with a homemade nanofibrous membrane reactor. The properties in this process of the immobilized laccase on PAN, PAN/MMT as well as PAN/MMT/GO with different weight ratios of MMT and GO were investigated. These membranes were successfully applied for removal of catechol from an aqueous solution. Scanning electron microscope images revealed different morphologies of the enzyme aggregates on different supports. After incorporation of MMT or MMT/GO, the optimum pH showed an alkaline shift to 4, compared to 3.5 for laccase immobilized on pure PAN nanofibers. The optimum temperature was at 55 °C for all the immobilized enzymes. Besides, the addition of GO improved the operational stability and storage stability. A 39% ± 2.23% chemical oxygen demand (COD) removal from the catechol aqueous solution was achieved. Experimental results suggested that laccase, PAN, adsorbent nanoparticles (MMT/GO) can be combined together for catechol treatment in industrial applications. PMID:24651612

Wang, Qingqing; Cui, Jing; Li, Guohui; Zhang, Jinning; Li, Dawei; Huang, Fenglin; Wei, Qufu

2014-01-01

86

Surface Behavior in Deuterium Permeation through Erbium Oxide Coating  

International Nuclear Information System (INIS)

Full text: Control of tritium permeation through structural materials is a key investigation for realization of an operative fuel cycle in fusion blanket concepts. Recent years, investigations on erbium oxide thin films have been demonstrated as a promising candidate for tritium permeation barrier. In this study, permeation measurements and structural analyses have been performed to clarify a surface behavior of deuterium permeation through the erbium oxide coatings deposited by a physical vapor deposition technique. The erbium oxide coatings were deposited by filtered vacuum arc deposition on one side or both sides of reduced activation ferritic/martensitic F82H and JLF-1 steel substrates at room temperature. The permeability of the samples with a 2.6 micron-thick erbium oxide layer on one side and 1.3 micron-thick layers on both sides has been measured by a gas-driven deuterium permeation apparatus. Permeation reduction factors of 1000 and 10 000 have been evaluated respectively, which means the both-sides coated sample has shown one order of magnitude lower permeation flux than that coated on one side in spite of the same effective thickness. In addition, the activation energies of permeation through each sample are estimated 81 and 117 kJ/mol by temperature dependence of the permeability. That indicates the surface reactions on the coating possess higher activation energies than diffusion process. The deuterium permeation behavior has been examined with 1.3 micron-thick coatings deposited on one side facing to the high and low deuterium pressure sides. The coating on the high deuterium pressure side has 7 times higher permeation reduction factor than that of the coating facing to the low pressure side. Additionally, X-ray diffraction spectra of the coated samples after the permeation measurements have shown an orientation of the erbium oxide on the coating facing to the high deuterium pressure side, which can cause the difference of permeability. Furthermore, compared to the result of the both-sides coated sample, the value of permeation reduction factor can be described not by addition but by multiplication of those of the coatings facing to each side. This result suggests an important finding that the surface reaction probability affects dominantly the deuterium permeation through the both-coated sample. (author)

87

XPS characterisation of plasma treated and zinc oxide coated PET  

Science.gov (United States)

At first, X-ray photoelectron spectroscopy (XPS) analyses of reference and carbon dioxide plasma treated polyethylene terephthalate (PET) were carried out. Significant chemical modifications were outlined in the treated PET surface in comparison with the reference one. The formation of new oxygenated groups was evidenced. These modifications heighten the level of interactions between the polymer substrate and the deposited coating. In a second stage, zinc oxide thin films were elaborated by r.f. magnetron sputtering from a ceramic target and with a reactive gas (mixture of argon-1% oxygen) under optimised conditions on CO 2 plasma treated PET. The interfacial chemistry between the plasma treated PET and the zinc oxide was also studied by XPS. The line shape changes in the high-resolution core level spectra of carbon C1s, oxygen O1s, and zinc (Zn2p3/2, Zn3p), with the progressive deposition of zinc oxide coatings being recorded. The obtained spectra were fitted to mixed Gaussian-Lorentzian components using XPS CASA software. An interaction scheme between the zinc oxide thin layer and its polymer substrate, in the first stage of deposition, was proposed and checked by corroborating the findings of the different XPS spectra and their decompositions. It suggests the formation of Zn sbnd O sbnd C complexes at the interface, which are promoted by an electron transfer from zinc to oxygen in oxygenated species, mainly alcohol groups, generated by the CO 2 plasma treatment of PET.

Amor, S. Ben; Jacquet, M.; Fioux, P.; Nardin, M.

88

XPS characterisation of plasma treated and zinc oxide coated PET  

International Nuclear Information System (INIS)

At first, X-ray photoelectron spectroscopy (XPS) analyses of reference and carbon dioxide plasma treated polyethylene terephthalate (PET) were carried out. Significant chemical modifications were outlined in the treated PET surface in comparison with the reference one. The formation of new oxygenated groups was evidenced. These modifications heighten the level of interactions between the polymer substrate and the deposited coating. In a second stage, zinc oxide thin films were elaborated by r.f. magnetron sputtering from a ceramic target and with a reactive gas (mixture of argon-1% oxygen) under optimised conditions on CO2 plasma treated PET. The interfacial chemistry between the plasma treated PET and the zinc oxide was also studied by XPS. The line shape changes in the high-resolution core level spectra of carbon C1s, oxygen O1s, and zinc (Zn2p3/2, Zn3p), with the progressive deposition of zinc oxide coatings being recorded. The obtained spectra were fitted to mixed Gaussian-Lorentzian components using XPS CASA software. An interaction scheme between the zinc oxide thin layer and its polymer substrate, in the first stage of deposition, was proposed and checked by corroborating the findings of the different XPS spectra and their decompositions. It suggests the formation of Zn-O-C complexes at the interface, which are promoted by an electron transfer from zinc to oxygen in oxygenated species, mainly alcohol groups, generated by the CO2 plasma treatment of PET.

89

XPS characterisation of plasma treated and zinc oxide coated PET  

Energy Technology Data Exchange (ETDEWEB)

At first, X-ray photoelectron spectroscopy (XPS) analyses of reference and carbon dioxide plasma treated polyethylene terephthalate (PET) were carried out. Significant chemical modifications were outlined in the treated PET surface in comparison with the reference one. The formation of new oxygenated groups was evidenced. These modifications heighten the level of interactions between the polymer substrate and the deposited coating. In a second stage, zinc oxide thin films were elaborated by r.f. magnetron sputtering from a ceramic target and with a reactive gas (mixture of argon-1% oxygen) under optimised conditions on CO{sub 2} plasma treated PET. The interfacial chemistry between the plasma treated PET and the zinc oxide was also studied by XPS. The line shape changes in the high-resolution core level spectra of carbon C1s, oxygen O1s, and zinc (Zn2p3/2, Zn3p), with the progressive deposition of zinc oxide coatings being recorded. The obtained spectra were fitted to mixed Gaussian-Lorentzian components using XPS CASA software. An interaction scheme between the zinc oxide thin layer and its polymer substrate, in the first stage of deposition, was proposed and checked by corroborating the findings of the different XPS spectra and their decompositions. It suggests the formation of Zn-O-C complexes at the interface, which are promoted by an electron transfer from zinc to oxygen in oxygenated species, mainly alcohol groups, generated by the CO{sub 2} plasma treatment of PET.

Ben Amor, S., E-mail: sofiene_us@yahoo.com [Ecole Preparatoire aux Academies Militaires de Sousse, avenue Marechal Tito, 4029 Sousse (Tunisia); Laboratoire Energie et Environnement, 03/UR/13-06, ISSATS, Cite Ibn Khaldoun, Sousse 4003 (Tunisia); Jacquet, M. [Laboratoire des Materiaux Inorganiques, UPRES A 6002, Universite Blaise Pascal, F-63177 Aubiere Cedex (France); Fioux, P.; Nardin, M. [Institut de Chimie des Surfaces et Interfaces, UPR-CNRS 9069, 15 rue Jean Starcky, BP 2488, F-68057 Mulhouse Cedex (France)

2009-02-15

90

Novel transparent conducting sol-gel oxide coatings  

International Nuclear Information System (INIS)

This work focuses on the preparation of novel ternary transparent conducting oxide coatings on glass by the sol-gel method. The coatings were deposited by spin-coating from solutions of appropriate metal precursors and heat-treated at different heat-treatment procedures. An increase in electrical conductivity was achieved by a final forming gas treatment. Best electrical and optical properties have been obtained for coatings of crystalline Zn2SnO4, Zn3In2O6 and Zn5In2O8 and X-ray amorphous ZnSnO3 with resistivities in the order of 10-2-10-1 ? cm, an average transmission in the visible of 85% and an average surface roughness of ? 1 nm. ZnGa2O4 and GaSbO4 coatings showed no electrical conductivity. For Zn2SnO4 coatings, a restricted crystallite growth was observed probably due to phase segregation effects. Electrical properties of coatings in the system ZnO-In2O3 were interpreted on the basis of the percolation theory

91

Transformation of bisphenol A by manganese oxide-coated sand.  

Science.gov (United States)

Oxidative transformation of organic contaminants by manganese oxides was commonly investigated with pure MnO(2) suspension, which deviates from the fact that natural manganese oxides are seldom present as a pure form in the natural environment. In this study, we prepared manganese oxide-coated sand (MOCS) and evaluated its oxidative capacity using bisphenol A (BPA) as the model compound. BPA was transformed by MOCS and the reaction followed an exponential decay model. The reaction was pH dependent and followed the order of pH 4.5>pH 5.5>pH 6.5>pH 7.5>pH 8.6>pH 9.6, indicating that acidic conditions facilitated BPA transformation while basic conditions disfavored the reaction. Coexisting metal ions exhibited inhibitory effects and followed the order of Fe(3+) > Zn(2+) > Cu(2+) > Ca(2+) > Mg(2+) > Na(+). Transformation of BPA by MOCS was much slower than that by pure MnO(2) suspension. However, similar transformation products were identified in both studies, suggesting the same reaction pathways. This work suggests that the reactivity of MnO(2) in the environment might be overestimated if extrapolating the result from the pure MnO(2) suspension because natural MnO(2) is mainly present as coating on the surface of soils and sediments. PMID:22752814

Lin, Kunde; Peng, Yiwen; Huang, Xinwen; Ding, Jiafeng

2013-03-01

92

The utilization of welding technologies in the treatment of ZrO2-based oxide coatings - the phase and structural aspects of remelting  

International Nuclear Information System (INIS)

Improving the method of remelting plasma-sprayed oxide coatings is done chiefly based on laser technologies, which is indicated by numerous studies published in both domestic and foreign specialist magazines. In the case of present study, an alternative method of remelting has been applied, which uses welding sources of heat. Because of thermophysical and electrical properties of oxide compositions used, a modification of the welding stand turned out to be necessary, which involved primarily equipping it with an additional, independent electrode and nozzle unit. The application of the above solution provided a capability of using the thermal energy of the arc, without engaging the coating in the process of arc generation and stabilization. The structural and phase effects of remelting oxide coatings by using the developed unit is presented in this article. (author)

93

Structure and apatite induction of a microarc-oxidized coating on a biomedical titanium alloy  

Science.gov (United States)

An oxide coating with nanostructure was prepared by micro-arc oxidation (MAO) on a biomedical Ti-24Nb-4Zr-7.9Sn alloy. Chemical composition of the coating mainly includes O, Ti, Nb, Ca, P, Na, Zr and Sn, where the ratio of Ca/P is about 1.6. Ti, Nb, Zr and Sn participate in the oxidation to form TO 2, Nb 2O 5, ZrO 2 and SnO 2 nanocrystals, while Ca, P and Na are present in the form of amorphous phases. After alkali treatment, the surface of the MAO coating becomes rough, and Na concentration increases remarkably while P disappears basically. The alkali treated coating shows better apatite forming ability than the untreated one, as evidenced by apatite formation after SBF immersion for 7 days. The improvement of apatite forming ability of the modified coating is attributed to the formation of a sodium titanate layer and numbers of submicron-scale network flakes. The enhancement of the surface wettability of the alkali treated coating also plays an important role in promoting the apatite forming ability.

Zhao, G. L.; Li, X.; Xia, L.; Wen, G.; Song, L.; Wang, X. Y.; Wu, K.

2010-12-01

94

Adsorbent phosphates  

Science.gov (United States)

An adsorbent which uses as its primary ingredient phosphoric acid salts of zirconium or titanium is presented. Production methods are discussed and several examples are detailed. Measurements of separating characteristics of some gases using the salts are given.

Watanabe, S.

1983-01-01

95

Studies on anodic oxide coating with low absorptance and high emittance on aluminum alloy 2024  

Energy Technology Data Exchange (ETDEWEB)

Anodization of AA 2024 in sulfuric acid bath containing glycerol, lactic acid and ammonium metavenadate has been studied to develop white anodic oxide coating. Investigation on the influence of various operating parameters - coating thickness, current density and ammonium metavenadate concentration on the optical properties was carried out to optimize the process. Infrared, atomic absorption spectroscopic techniques and scanning electron micrograph were used to characterize the coating. The obtained oxide coating provides a ratio of solar absorptance ({alpha}) to infrared emittance ({epsilon}), as low as 0.2. The optical properties and hardness values measured under optimum experimental conditions support its use as a thermal control coating.

Siva Kumar, C. [Department of Post-graduate studies in Chemistry, Central College, Bangalore (India); Sharma, A.K. [Thermal Process Section, ISRO Satellite Centre, Vimanapura Post, Bangalore (India); Mahendra, K.N.; Mayanna, S.M. [Department of Post-graduate studies in Chemistry, Central College, Bangalore (India)

2000-01-01

96

Synthesis and electrochemical characterization of porous niobium oxide coated 316L SS for orthopedic applications  

International Nuclear Information System (INIS)

Niobium oxide was prepared using sol-gel process and coated on 316L stainless steel (SS) substrate via dip-coating technique. The surface characterization results after a thermal treatment revealed that the coated surface was porous, uniform and well crystalline on the substrate. The corrosion resistance and bioactivity of the porous niobium oxide coated 316L SS in simulated body fluid (SBF) solution was evaluated. The in vitro test revealed a layer of carbonate-containing apatite formation over the coated porous surface. The results indicated that the porous niobium oxide coated 316L SS exhibited a high corrosion resistance and an enhanced biocompatibility in SBF solution.

97

Covalently crosslinked fly ash/poly(acrylic acid-co-acrylamide) composite microgels as novel magnetic selective adsorbent for Pb²? ion.  

Science.gov (United States)

In order to improve the performance of treating waste-water with wastes, the magnetic fly ash (FA) particles were surface-modified with polymerizable groups as the crosslinker for the copolymerization with acrylic acid (AA) and acrylamide (AM) by a facile inverse suspension polymerization process, without any foreign organic crosslinker added. The optimized beadlike magnetic fly ash/poly(acrylic acid-co-acrylamide) composite microgels (FA/P(AA-AM)) with 3-dimensional crosslinking skeleton structure were selected as the magnetic selective microgel adsorbent for Pb(2+) ion, through a series of L(9)(3(4)) orthogonal experiments. It was found that the magnetic FA particles could improve the strength stability of the FA/P(AA-AM) composite microgels, also provide the ability of magnetic separation. PMID:24863766

Jiang, Liping; Liu, Peng

2014-07-15

98

Preparation of Surface Adsorbed and Impregnated Multi-walled Carbon Nanotube/Nylon-6 Nanofiber Composites and Investigation of their Gas Sensing Ability  

Directory of Open Access Journals (Sweden)

Full Text Available We have prepared electrospun Nylon-6 nanofibers via electrospinning, and adsorbed multi-walled carbon nanotubes (MWCNTs onto the surface of Nylon-6 fibers using Triton® X-100 to form a MWCNTs/Nylon-6 nanofiber composite. The dispersed MWCNTs have been found to be stable in hexafluoroisopropanol for several months without precipitation. A MWCNTs/Nylon-6 nanofiber composite based chemical sensor has demonstrated its responsiveness towards a wide range of solvent vapours at room temperature and only mg quantities of MWCNTs were expended. The large surface area and porous nature of the electrospun Nylon-6/MWCNT nanofibers facilitates greater analyte permeability. The experimental analysis has indicated that the dipole moment, functional group and vapour pressure of the analytes determine the magnitude of the responsiveness.

Velmurugan Thavasi

2009-01-01

99

Optical properties and environmental stability of oxide coatings deposited by reactive sputtering.  

Science.gov (United States)

Refractory metal-oxide coatings are deposited by reactive dc magnetron sputtering in an oxygen environment. The optical constants and the environmental stability of silicon oxide, aluminium oxide, hafnium oxide, zirconium oxide, tantalum oxide, titanium oxide, and a blend of hafnium oxide with silicon oxide are investigated. Properties of both single-layer and multilayer interference filters are examined. PMID:20856375

Edlou, S M; Smajkiewicz, A; Al-Jumaily, G A

1993-10-01

100

Studies on yttrium oxide coatings for corrosion protection against molten uranium  

International Nuclear Information System (INIS)

Yttrium oxide is resistant to corrosion by molten uranium and its alloys. Yttrium oxide is recommended as a protective oxide layer on graphite and metal components used for melting and processing uranium and its alloys. This paper presents studies on the efficacy of plasma sprayed yttrium oxide coatings for barrier applications against molten uranium

 
 
 
 
101

Adsorbent with Enhanced Protein Binding Capacity and Selectivity.  

Science.gov (United States)

The invention discloses an adsorbent composition in which each ligand has a cluster of functional groups. This adsorbent composition is designed to enhace binding affinity and specificity for biomolecules. The invention also discloses a method for adsorbi...

A. S. H. Potty, R. C. Willson, S. Balan

2005-01-01

102

Tungsten bronze-based nuclear waste form ceramics. Part 2: Conversion of granular microporous tungstate polyacrylonitrile (PAN) composite adsorbents to leach resistant ceramics  

Science.gov (United States)

Conversion of a granular molybdenum-doped, hexagonal tungsten bronze (MoW-HTB)-polyacrylonitrile (PAN) composite adsorbent to a leach resistant ceramic waste form capable of immobilizing adsorbed Cs + and Sr 2+ has been achieved by heating in air at temperatures in the range 600-1200 °C. Thermal treatment of the Cs- and Sr-loaded composite material at 1000 °C was sufficient to invoke a 60% reduction in volume of the composite while still retaining its spherical morphology. Cs-133 MAS NMR studies of this sample suite at 9.4 T and 14.1 T showed that multiple Cs sites are present throughout the entire thermal treatment range. Scanning electron microscopy investigations of the phase assemblages resulting from thermal treatment demonstrated that the full complement of Cs, and the majority of Sr, partitions into HTB phases (A 0.16-0.3MO 3; A = Cs +, Sr 2+ and Na +; M = Mo, W). The potentially reducing conditions resulting from the removal of the PAN matrix or the presence of high concentrations of Na + relative to either Cs + or Sr 2+ does not retard the formation of the high temperature HTB phases. The fraction of Cs + and Sr 2+ leached from the tungstate phase assemblages was superior or comparable with cesium hollandite (Cs 0.8Ba 0.4Ti 8O 18; f = ?8 × 10 -5; rate = strontium titanate (SrTiO 3; f = 3.1 × 10 -3; rate = 2.63 × 10 -4 g/m 2/day), respectively, using a modified PCT test in Millipore water at 90 °C. Furthermore, where aggressive leaching conditions were employed (0.1 M HNO 3; 150 °C; 4 days), the tungstate phase assemblages displayed leach resistance almost two orders of magnitude greater than the reference phases.

Griffith, Christopher S.; Sebesta, Ferdinand; Hanna, John V.; Yee, Patrick; Drabarek, Elizabeth; Smith, Mark E.; Luca, Vittorio

2006-11-01

103

Tungsten bronze-based nuclear waste form ceramics. Part 2: Conversion of granular microporous tungstate-polyacrylonitrile (PAN) composite adsorbents to leach resistant ceramics  

International Nuclear Information System (INIS)

Conversion of a granular molybdenum-doped, hexagonal tungsten bronze (MoW-HTB)-polyacrylonitrile (PAN) composite adsorbent to a leach resistant ceramic waste form capable of immobilizing adsorbed Cs+ and Sr2+ has been achieved by heating in air at temperatures in the range 600-1200 deg. C. Thermal treatment of the Cs- and Sr-loaded composite material at 1000 deg. C was sufficient to invoke a 60% reduction in volume of the composite while still retaining its spherical morphology. Cs-133 MAS NMR studies of this sample suite at 9.4 T and 14.1 T showed that multiple Cs sites are present throughout the entire thermal treatment range. Scanning electron microscopy investigations of the phase assemblages resulting from thermal treatment demonstrated that the full complement of Cs, and the majority of Sr, partitions into HTB phases (A0.16-0.3MO3; A = Cs+, Sr2+ and Na+; M = Mo, W). The potentially reducing conditions resulting from the removal of the PAN matrix or the presence of high concentrations of Na+ relative to either Cs+ or Sr2+ does not retard the formation of the high temperature HTB phases. The fraction of Cs+ and Sr2+ leached from the tungstate phase assemblages was superior or comparable with cesium hollandite (Cs0.8Ba0.4Ti8O18; f = ?8 x 10-5; rate = -4 g/m2/day) and strontium titanate (SrTiO3; f = 3.1 x 10-3; rate = 2.63 x 10-4 g/m2/day), respectively, using a modified PCT test in Millipore water at 90 deg. C. Furthermore, where aggressive leaching conditions were employed (0.1 M HNO3; 150 deg. C; 4 days), the tungstate phase assemblages displayed leach resistance almost two orders of magnitude greater than the reference phases

104

Preparation and characterization of niobium oxide coated cellulose fiber  

International Nuclear Information System (INIS)

Hydrous niobium(V) oxide has been investigated with respect to its surface acid strength, ion exchange capacity, and use as specific sorbent for many metal ions. The Nb2O5/cellulose composite was prepared by reacting ?-cellulose with NbCl5-n (OC2H5)n, in nonaqueous solvent, under nitrogen atmosphere and submitting the obtained material to hydrolysis. An increase in the crystallinity degree is observed in the composite material because the precursor reagent reacts with the amorphous phase of the cellulose fibers. Loadings between 4.5 and 16.0% of the oxide were achieved and in every case the oxide particles uniformly cover the fiber surface. Lewis and Broensted acid sites were determined by using pyridine as the basic molecular probe

105

Structures and magnetic properties of iron- and cobalt-containing oxide coatings on an aluminum alloy formed in electrolytes via plasma electrolytic oxidation  

Science.gov (United States)

The effect of the nature of the supporting electrolyte in the composition of electrolytic suspensions containing dispersed particles of Fe(III) and Co(II) hydroxides, and of anodic and bipolar anodic-cathodic polarization on features of the formation, composition, and magnetic characteristics of oxide coatings is studied. In all cases, iron and cobalt are incorporated into the coatings and are concentrated predominantly in pores. The pores of the coatings include particles consisting of the reduced metals, presumably surrounded by oxide or hydroxide shells. The electrolyte composition affects the concentration and ratio of the metals in the particles. A correlation is observed between the ferro- or ferrimagnetism of the coatings and the content and ratio of cobalt and iron in the pores.

Rudnev, V. S.; Morozova, V. P.; Lukiyanchuk, I. V.; Adigamova, M. V.; Tkachenko, I. A.; Ustinov, A. Yu.; Kharitonskii, P. V.; Frolov, A. M.

2014-05-01

106

Conception of operation of in situ oxide coatings concerning liquid metal cooling systems  

International Nuclear Information System (INIS)

The corrosion aggressiveness of liquid metals with regard to the structural materials and protective coatings is one of the main issues of up-to-date reactor materials science. In this paper the interaction of components in the Fe[Cr]/Pb[O] and V[O]/Li[Er] systems was considered and the kinetic models of formation and growth of the oxide layers on the surface of structural materials during the contact with liquid metals were proposed. The interaction of V-alloy with oxygen and liquid lithium is considered from the viewpoint of the coating operation at the interface. The in situ oxide coating, in turn, is considered as a synergetic object, which evolves (nucleates, grows, becomes stabilize and degrades). The charging procedure of V-4Ti-4Cr alloy by oxygen was considered using the concepts 6f theory of the low-temperature inner oxidation. The model of formation of the inner oxidation zone was proposed. The deoxidation of V-alloy during the contact with Li[Er] was considered as a surface reaction of oxygen with erbium and as a diffusion process accompanied by the structure-phase transformation in the bulk of solid metal. The corrosion behaviour of Fe-based alloys in the Pb/Pb-Bi melts as a function of temperature; oxygen concentration in liquid metal., material composition and exposure time was investigated. The main existed experimental data concerning passivation. of steels in heavy metal melts were described and. generalised. The features of double oxide layer evolutiThe features of double oxide layer evolution depending on the various experimental conditions were revealed and discussed. Based on. the experimental results and thorough analysis of the existed data the phenomenological. model of growth. of the duplex scale on the surface of steels contacting with. heavy metal melts containing oxygen. was proposed. The model demonstrates the main stages of origin, growth and degradation of double oxide layer in. the liquid metal environment. The numerical simulation of the oxidation kinetics of a model material Armco-Fe in Pb melt saturated by oxygen (10-3 wt.%O) at 550 deg C was carried out. (authors)

107

Measurement of thermal conductivity of the oxide coating on autoclaved monel-400  

International Nuclear Information System (INIS)

Thermal conductivity of the oxide coating on monel-400 has been measured by a direct method. The oxide coating is applied on an electrically conducting wire having stable characteristics. The wire is placed in a constant temperature bath and a constant direct current is passed through it. The wire gets heated and loses heat to the surrounding. Temperature is measured by considering it as a resistance thermometer. A convection heat transfer coefficient, which is difficult to measure experimentally but is involved in the analytical expression for thermal conductivity, is eliminated by connecting a second uncoated wire of a noble metal having similar surface finish as that of the coated wire in series with it. The accuracy of the method is nearly six percent. However, the method is not easily applicable for very thin (thickness <= 1?), highly porous coatings and materials having relatively large thermal conductivity. (M.G.B.)

108

Rare earth elements and neodymium isotopes in ferromanganese oxide coatings of Cenozoic foraminifera from the Atlantic Ocean  

International Nuclear Information System (INIS)

An evaluation has been made of the method of establishing the REE contents and patterns and Nd isotopic compositions of sea water over Cenozoic time from their record in the FeMn-oxide coatings of foraminiferal calcite. Using 0-60 Ma samples from the Rio Grande Rise (DSDP Site 357) it has been established that the REE contents of the coatings are generally similar to those of recent samples. However, in the Cenozoic samples the surface coatings have been diagenetically modified under suboxic conditions resulting in a distinctly different REE pattern although the original 143Nd/144Nd ratios appear to have been preserved. The Nd isotopic curve for Cenozoic sea water in the S. Atlantic shows clear temporal trends, although these are not so extreme as to show 143Nd/144Nd ratios outside the range observed in modern sea water. With the principal exception of the oldest samples there is an approximate inverse relationship between the Nd and Sr isotopic compositions of foraminifera. The Nd isotopic curve appears to be a potentially useful tracer of ocean palaeochemistry. (author)

109

Development of Niobium Oxide Coatings on Sand-Blasted Titanium Alloy Dental Implants  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The purpose of this study was to use scanning electron microscopy (SEM) evaluation to determine the optimal anodizetion conditions needed to generate niobium oxide coatings on titanium alloy dental implant screws. Sand-blasted titanium alloy dental implants were anodized in dilute hydrofluoric acid (HF(aq)) solution using a Sorensen DLM 300-2 power supply. The HF concentration and anodization time were varied and the resulting implant surfaces were evaluated using a Jeo...

Alge, Daniel L.; Meoghan MacPherson; Chu, Tien-mien G.; Karlinsey, Robert L.; Mackey, Allen C.

2012-01-01

110

Electrochemical Behavior of Chemical Vapor Deposited Protective Aluminum Oxide Coatings on Ti6242 Titanium Alloy  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The electrochemical behavior at room temperature in a neutral sodium chloride aqueous solution of four types of metallorganic chemical vapor deposited aluminum oxide coatings on commercial Ti6242 titanium alloy was investigated. Polarization and electrochemical impedance curves revealed that porosity free, amorphous alumina coatings provide a two order of magnitude improvement of the corrosion resistance with regard to the bare alloy. Crystallized alumina as well as amorphous AlO(OH) only sli...

Boisier, Gre?gory; Raciulete, Monica; Same?lor, Diane; Pe?be?re, Nadine; Gleizes, Alain; Vahlas, Constantin

2008-01-01

111

Surface characteristics and electrochemical corrosion behavior of a pre-anodized microarc oxidation coating on titanium alloy.  

Science.gov (United States)

A porous bioactive titania coating on biomedical ? titanium alloy was prepared by pre-anodization followed by micro arc oxidation technology. The effects of pre-anodization on the phase constituent, morphology and electrochemical corrosion behavior of the microarc oxidation coating were investigated. The results show that pre-anodization has less influence on the phase constituent and the surface morphology of the microarc oxidation coating, but improves the inner layer density of the microarc oxidation coating. The decrease of plasma discharge strength due to the presence of the pre-anodized oxide film contributes to the formation of the compact inner layer. The pre-anodized microarc oxidation coating effectively inhibits the penetration of the electrolyte in 0.9% NaCl solution and thus increases the corrosion resistance of the coated titanium alloy in physiological solution. PMID:23910276

Cui, W F; Jin, L; Zhou, L

2013-10-01

112

Removal of heavy metal ions by iron oxide coated sewage sludge.  

Science.gov (United States)

The municipal sewage sludge was modified with iron oxide employed in metal ions removal. The surface modification method was proposed and the effect of parameters in the preparation was studied. The iron oxide coated sludge had higher surface area, pore volume and iron content, compared to uncoated sludge. The suitable conditions for removal of Cu(II), Cd(II), Ni(II) and Pb(II) ions from solutions were investigated using batch method. The suitable pH value in the extraction was 7 for adsorption of Cd(II) and Ni(II), 6 for Cu(II) and 5 for Pb(II) ions. The presence of NaNO(3), Ca(NO(3))(2) and Na(2)SO(4) in metal solution in the concentration of 0.01 M and 0.50 M could reduce the removal efficiency. The adsorption isotherms for the adsorption of the metal ions were defined by Langmuir relation. The maximum adsorption capacity of the iron oxide coated sludge for Cu(II), Cd(II), Ni(II) and Pb(II) was 17.3, 14.7, 7.8 and 42.4 mg g(-1), respectively. The adsorption kinetics for every metal ions followed pseudo-second order model. The metal removal from wastewater by iron oxide coated sludge was also demonstrated. PMID:21167637

Phuengprasop, Thapanapong; Sittiwong, Jarinya; Unob, Fuangfa

2011-02-15

113

Rare earth oxide coatings to decrease high temperature degradation of chromia forming alloys  

Scientific Electronic Library Online (English)

Full Text Available SciELO Brazil | Language: English Abstract in english The addition of small quantities of reactive elements such as rare earths (RE) to chromia or alumina forming alloys improves the high temperature oxidation resistance. Traditionally, these elements are alloying additions or are added as oxides to form a dispersion. The alloys can also be coated with [...] RE oxides. Several methods can be used to coat alloy substrates with RE oxides and the sol-gel process is considered to be quite efficient, as it generates the very small oxide particles. This paper presents the influence of surface coatings of Ce, La, Pr, and Y oxide gels on the oxidation behavior of an Fe-20Cr alloy at 1000 °C. The morphology of the rare earth (RE) oxide coatings varied with the nature of RE. The oxidation rate of RE oxide coated Fe-20Cr was significantly less than that of the uncoated alloy. The extent of influence the RE oxide coating exercised on the oxidation rate decreased in the following order: La, Ce, Pr, Y. The scale formed in the presence of RE oxide was very thin, fine grained and adherent chromia. A direct correlation between rare earth ion radius and the extent of influence on chromia growth rate at 1000 °C was observed.

Stela Maria de Carvalho, Fernandes; Lalgudi Venkataraman, Ramanathan.

114

Rare earth oxide coatings to decrease high temperature degradation of chromia forming alloys  

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Full Text Available The addition of small quantities of reactive elements such as rare earths (RE to chromia or alumina forming alloys improves the high temperature oxidation resistance. Traditionally, these elements are alloying additions or are added as oxides to form a dispersion. The alloys can also be coated with RE oxides. Several methods can be used to coat alloy substrates with RE oxides and the sol-gel process is considered to be quite efficient, as it generates the very small oxide particles. This paper presents the influence of surface coatings of Ce, La, Pr, and Y oxide gels on the oxidation behavior of an Fe-20Cr alloy at 1000 °C. The morphology of the rare earth (RE oxide coatings varied with the nature of RE. The oxidation rate of RE oxide coated Fe-20Cr was significantly less than that of the uncoated alloy. The extent of influence the RE oxide coating exercised on the oxidation rate decreased in the following order: La, Ce, Pr, Y. The scale formed in the presence of RE oxide was very thin, fine grained and adherent chromia. A direct correlation between rare earth ion radius and the extent of influence on chromia growth rate at 1000 °C was observed.

Fernandes Stela Maria de Carvalho

2004-01-01

115

Cavitation erosion resistance of microarc oxidation coating on aluminium alloy  

Science.gov (United States)

Two ceramic coatings are prepared on 2124 aluminum alloy by microarc oxidation (MAO) technology. To explore the cavitation erosion resistance of the MAO coating, cavitation tests were performed by using a rotating-disk test rig. The mass losses, surface morphologies, chemical compositions and the phase constituents of the samples after cavitation tests were examined by using digital balance, scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS) and X-ray diffraction (XRD), respectively. The results indicate that the MAO coatings can extend the incubation period of aluminum alloy, and thus enhance the cavitation erosion resistance as compared to the untreated aluminum alloy samples. After duration of 63 h cavitation test, a lot of erosion pits and the particles in various shapes can be observed on the surfaces of the aluminum alloy samples, while only a few erosion pits are observed on the MAO coatings. Moreover, the mean depths of erosion on the MAO coatings are lower in the first 30 h and are independent on erosion time. The results show that the cavitation erosion of MAO coating is governed by water mechanical impaction, resulting from the effects of brittle fracture of the MAO coating.

Cheng, Feng; Jiang, Shuyun; Liang, Jun

2013-09-01

116

High capacity magnetic mesoporous carbon-cobalt composite adsorbents for removal of methylene green from aqueous solutions.  

Science.gov (United States)

Mesoporous carbons containing cobalt nanoparticles are synthesized by tri-or quad-constituent self assembly of Pluronic F127, phenol-formaldehyde oligomer (resol), cobalt acetylacetonate (acac), and optionally tetraethyl orthosilicate (TEOS, optional). Upon pyrolysis in N(2) atmosphere, the resol provides sufficient carbon yield to maintain the ordered structure, while decomposition of the Co(acac) yields cobalt nanoparticles. To provide increased surface area, the dispersed silicate from condensation of TEOS can be etched after carbonization to yield micropores, Without silica templated micropores, the surface area decreases as the cobalt content increases, but there is a concurrent increase in the volume-average pore diameter (BHJ) and a dramatic increase in the adsorption capacity of methylene green with the equilibrium adsorption capacity from 2 to 90 mg/g with increasing Co content. Moreover, the surface area and pore size of mesoporous composites can be dramatically increased by addition of TEOS and subsequent etching. These composites exhibit extremely high adsorption capacity up to 1151 mg/g, which also increases with increases in the Co content. Additionally, the inclusion of cobalt nanoparticles provides magnetic separation from aqueous suspension. The in situ synthesis of the Co nanoparticles yields to a carbon shell that can partially protect the Co from leaching in acidic media; after 96 h in 2 M HCl, the powders remain magnetic. PMID:22975394

Dai, Mingzhi; Vogt, Bryan D

2012-12-01

117

Electromagnetic characteristics of manganese oxide-coated Fe3O4 nanoparticles at 2-18 GHz  

Science.gov (United States)

The dielectric and magnetic properties of manganese oxide-coated Fe3O4 nanoparticles (NPs) were measured by the transmission/reflection method in 2-18 GHz. MnOx-coated Fe3O4 NPs were prepared by sol-gel method followed by heat-treating at 300, 400, and 500 °C, respectively. The heat-treated powders were then used as magnetic fillers and added to an epoxy resin to prepare MnOx-coated Fe3O4 composites for the complex permittivity (?'-j??) and permeability (?'-j??) measurements. After the sol-gel process, the coating of manganese oxide (mixture of major Mn2O3 and minor Mn3O4) reduced the value of ?'. The lower the heat-treating temperature, the larger the decrease in ?'. The relative decrease in ?', compared with uncoated Fe3O4 nanoparticles, is 28.7, 23.5, and 20.0% for coated MnOx heat-treated at 300, 400, and 500 °C, respectively, while the relative decrease in ?? is 74.1, 68.8, and 65.2%, respectively. In the present study, MnOx-coated Fe3O4 exhibited a significant decrease in dielectric loss tangent of ˜100% compared to that of uncoated NPs and can be of practical use for microwave components.

Yang, R. B.; Liang, W. F.; Lin, C. K.

2011-04-01

118

Origin of complex impact craters on native oxide coated silicon surfaces  

International Nuclear Information System (INIS)

Crater structures induced by impact of keV-energy Arn+ cluster ions on silicon surfaces are measured with atomic force microscopy. Complex crater structures consisting of a central hillock and outer rim are observed more often on targets covered with a native silicon oxide layer than on targets without the oxide layer. To explain the formation of these complex crater structures, classical molecular dynamics simulations of Ar cluster impacts on oxide coated silicon surfaces, as well as on bulk amorphous silica, amorphous Si, and crystalline Si substrates, are carried out. The diameter of the simulated hillock structures in the silicon oxide layer is in agreement with the experimental results, but the simulations cannot directly explain the height of hillocks and the outer rim structures when the oxide coated silicon substrate is free of defects. However, in simulations of 5 keV/atom Ar12 cluster impacts, transient displacements of the amorphous silicon or silicon oxide substrate surfaces are induced in an approximately 50 nm wide area surrounding the impact point. In silicon oxide, the transient displacements induce small topographical changes on the surface in the vicinity of the central hillock. The comparison of cluster stopping mechanisms in the various silicon oxide and silicon structures shows that the largest lateral momentum is induced in the silicon oxide layer during the impact; thus, the transient displacements on the surfacethe transient displacements on the surface are stronger than in the other substrates. This can be a reason for the higher frequency of occurrence of the complex craters on oxide coated silicon

119

Selection of a Commercial Anode Oxide Coating for Electro-oxidation of Cyanide  

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This paper presents a study of the performance of two commercial dimensionally stable anode (DSA®) oxide coatings in the electrochemical process for cyanide oxidation. The coatings studied were 70TiO2/30RuO2 and 55Ta2O5/45IrO2, on Ti substrate. The efficiency of both materials in the electro-oxidation of free cyanide was compared using linear voltammetry and electrolysis at constant potential. The 70TiO2/30RuO2 electrode shows a better performance in the electro-oxidation of free cyanide.

Lanza Marcos Roberto V.; Bertazzoli Rodnei

2002-01-01

120

Selection of a Commercial Anode Oxide Coating for Electro-oxidation of Cyanide  

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Full Text Available This paper presents a study of the performance of two commercial dimensionally stable anode (DSA® oxide coatings in the electrochemical process for cyanide oxidation. The coatings studied were 70TiO2/30RuO2 and 55Ta2O5/45IrO2, on Ti substrate. The efficiency of both materials in the electro-oxidation of free cyanide was compared using linear voltammetry and electrolysis at constant potential. The 70TiO2/30RuO2 electrode shows a better performance in the electro-oxidation of free cyanide.

Lanza Marcos Roberto V.

2002-01-01

 
 
 
 
121

Preparation and properties of poly(vinylidene fluoride nanocomposites blended with graphene oxide coated silica hybrids  

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Full Text Available Graphene oxide coated silica hybirds (SiO2-GO were fabricated through electrostatic assembly in this work, then blended with poly(vinylidene fluoride (PVDF by solution mixing to make PVDF nanocomposites. The interfacial interaction was investigated by scanning electron microscopy (SEM, polarized optical microscopy (POM and Fourier transform infrared spectroscopy (FTIR. The results showed that the interfacial interaction was enhanced by adding of SiO2-GO and strong hydrogen bonds were observed. The as-made nanocomposites were investigated using standard tensile test and dynamic mechanical analysis (DMA measurements, mechanical properties of PVDF with SiO2-GO hybrids showed limited improvement.

Q. Fu

2012-04-01

122

Photoluminescence blue shift of indium phosphide nanowire networks with aluminum oxide coating  

Energy Technology Data Exchange (ETDEWEB)

This paper describes our finding that optical properties of semiconductor nanowires were modified by depositing a thin layer of metal oxide. Indium phosphide nanowires were grown by metal organic chemical vapor deposition on silicon substrates with gold catalyst resulting in three-dimensional nanowire networks, and optical properties were obtained from the collective nanowire networks. The networks were coated with an aluminum oxide thin film deposited by plasma-enhanced atomic layer deposition. We studied the dependence of the peak wavelength of photoluminescence spectra on the thickness of the oxide coatings. A continuous blue shift in photoluminescence spectra was observed when the thickness of the oxide coating was increased. The observed blue shift is attributed to the Burstein-Moss effect due to increased carrier concentration in the nanowire cores caused by repulsion from intrinsic negative fixed charges located at the inner oxide surface. Samples were further characterized by scanning electron microscopy, Raman spectroscopy, transmission electron microscopy, and selective area diffractometry to better understand the physical mechanisms for the blue shift. (copyright 2014 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

Fryauf, David M.; Zhang, Junce; Norris, Kate J.; Diaz Leon, Juan J.; Oye, Michael M.; Kobayashi, Nobuhiko P. [Nanostructured Energy Conversion Technology and Research (NECTAR), Advanced Studies Laboratories, University of California, Santa Cruz, CA (United States); Baskin School of Engineering, University of California Santa Cruz, Santa Cruz, CA (United States); NASA Ames Research Center, Moffett Field, CA (United States); Wei, Min [Baskin School of Engineering, University of California Santa Cruz, Santa Cruz, CA (United States); School of Micro-Electronics and Solid-Electronics, University of Electronic Science and Technology of China, Chengdu (China)

2014-07-15

123

Photoluminescence blue shift of indium phosphide nanowire networks with aluminum oxide coating  

International Nuclear Information System (INIS)

This paper describes our finding that optical properties of semiconductor nanowires were modified by depositing a thin layer of metal oxide. Indium phosphide nanowires were grown by metal organic chemical vapor deposition on silicon substrates with gold catalyst resulting in three-dimensional nanowire networks, and optical properties were obtained from the collective nanowire networks. The networks were coated with an aluminum oxide thin film deposited by plasma-enhanced atomic layer deposition. We studied the dependence of the peak wavelength of photoluminescence spectra on the thickness of the oxide coatings. A continuous blue shift in photoluminescence spectra was observed when the thickness of the oxide coating was increased. The observed blue shift is attributed to the Burstein-Moss effect due to increased carrier concentration in the nanowire cores caused by repulsion from intrinsic negative fixed charges located at the inner oxide surface. Samples were further characterized by scanning electron microscopy, Raman spectroscopy, transmission electron microscopy, and selective area diffractometry to better understand the physical mechanisms for the blue shift. (copyright 2014 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

124

Sol-gel prepared active ternary oxide coating on titanium in cathodic protection  

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Full Text Available The characteristics of a ternary oxide coating, on titanium, which consisted of TiO2, RuO2 and IrO2 in the molar ratio 0.6:0.3:0.1, calculated on the metal atom, were investigated for potential application for cathodic protection in a seawater environment. The oxide coatings on titanium were prepared by the sol gel procedure from a mixture of inorganic oxide sols, which were obtained by forced hydrolysis of metal chlorides. The morphology of the coating was examined by scanning electron microscopy. The electrochemical properties of activated titanium anodes were investigated by cyclic voltammetry and polarization measurements in a H2SO4- and NaCl-containing electrolyte, as well as in seawater sampled on the Adriatic coast in Tivat, Montenegro. The anode stability during operation in seawater was investigated by the galvanostatic accelerated corrosion stability test. The morphology and electrochemical characteristics of the ternary coating are compared to that of a sol-gel-prepared binary Ti0.6Ru0.4O2 coating. The activity of the ternary coating was similar to that of the binary Ti0.6Ru0.4O2 coating in the investigated solutions. However, the corrosion stability in seawater is found to be considerably greater for the ternary coating.

VLADIMIR V. PANIC

2007-12-01

125

Influence of sodium silicate concentration on structural and tribological properties of microarc oxidation coatings on 2017A aluminum alloy substrate  

International Nuclear Information System (INIS)

In this paper, thick and hard oxide coatings resistant to wear were produced on 2017A-T6 Al alloy by the microarc oxidation (MAO) technique in an alkali electrolyte consisting of different sodium silicate concentrations (0-8 g/l). The coatings were characterized by means of optical microscopy, scanning electron microscopy (SEM), X-ray diffraction (XRD) and surface profilometry. Microhardness, scratch adhesion and pin-on-disk sliding wear tests were also performed to evaluate the tribological properties of the coatings. The influence of sodium silicate concentration on the structural and tribological properties of the MAO coatings was discussed. Results reveal that increasing sodium silicate concentration from 0 to 8 g/l in the electrolyte caused an increase in the electrolyte conductivity (from 7.71 to 18.1 mS/cm) and a decrease in positive final voltage (from 627 to 590 V) in the MAO process. In response to the increase in sodium silicate concentration, the thickness, surface roughness (Ra) and critical load (Lc) corresponding to adhesive failure of the coatings were increased simultaneously from 74 to 144 ?m, and 4.4 to 6.58 ?m, and 127.76 to 198.54 N, respectively. At the same time, the phase structure and composition of the coatings also varied by the participation of silicate ions in the reactions and their incorporation into the coating structure. Moreover, it was observed that the coating formed in the low sodium silicate concentration (4 g/l) had higher surface hardness (2020 HV) and improved wear resistance than the one (1800 HV) formed in the high sodium silicate concentration (8 g/l). The coatings produced in three different electrolytic solutions provided an excellent wear resistance and a load carrying capacity compared to the uncoated aluminum alloy.

126

A spectroscopic and microstructural study of oxide coatings produced on a Ti–6Al–4V alloy by plasma electrolytic oxidation  

International Nuclear Information System (INIS)

Highlights: ? PEO (plasma electrolytic oxidation) for production of oxide coatings on a Ti–6Al–4V alloy. ? Two different current modes namely pulsed unipolar and bipolar was used. ? Optical emission spectroscopy (OES) was used to characterize the PEO plasma. ? This is the first attempt to characterize spectroscopically the PEO plasma of Ti and its alloys. ? The discharge behavior effect on the formation and structure of the coating was determined. - Abstract: In this study, we have used PEO (plasma electrolytic oxidation) for the production of oxide coatings on a Ti–6Al–4V alloy at two different current modes, namely pulsed unipolar and bipolar. Optical emission spectroscopy (OES) in the visible and near UV band (280–800 nm) was used to characterize the PEO plasma. The emission spectra were recorded and the plasma temperature profile versus processing time was constructed using a line intensity ratios method. The aim of this work was to study the effect of the process parameters, including current mode and pulse duration time, on the plasma characteristics, surface morphology and microstructure and corrosion resistance of oxides grown on Ti–6Al–4V by PEO process. Scanning electron microscopy (SEM) with energy dispersive X-ray analysis (EDS) and X-ray diffraction (XRD) were used to study the coating microstructure, morphology and phase composition. The corrosion resistance of the coated and uncoated samples was examined by potentiodynamic polarintiodynamic polarization in a 3.5% NaCl solution. It was found that the plasma temperature profiles are significantly influenced by changing the current mode from unipolar to bipolar. The strongest discharges that are initiated at the interface between the substrate and the coating can be reduced or eliminated by using a bipolar current mode. This produces a thinner, denser and more corrosion-resistant coating.

127

A spectroscopic and microstructural study of oxide coatings produced on a Ti-6Al-4V alloy by plasma electrolytic oxidation  

Energy Technology Data Exchange (ETDEWEB)

Highlights: Black-Right-Pointing-Pointer PEO (plasma electrolytic oxidation) for production of oxide coatings on a Ti-6Al-4V alloy. Black-Right-Pointing-Pointer Two different current modes namely pulsed unipolar and bipolar was used. Black-Right-Pointing-Pointer Optical emission spectroscopy (OES) was used to characterize the PEO plasma. Black-Right-Pointing-Pointer This is the first attempt to characterize spectroscopically the PEO plasma of Ti and its alloys. Black-Right-Pointing-Pointer The discharge behavior effect on the formation and structure of the coating was determined. - Abstract: In this study, we have used PEO (plasma electrolytic oxidation) for the production of oxide coatings on a Ti-6Al-4V alloy at two different current modes, namely pulsed unipolar and bipolar. Optical emission spectroscopy (OES) in the visible and near UV band (280-800 nm) was used to characterize the PEO plasma. The emission spectra were recorded and the plasma temperature profile versus processing time was constructed using a line intensity ratios method. The aim of this work was to study the effect of the process parameters, including current mode and pulse duration time, on the plasma characteristics, surface morphology and microstructure and corrosion resistance of oxides grown on Ti-6Al-4V by PEO process. Scanning electron microscopy (SEM) with energy dispersive X-ray analysis (EDS) and X-ray diffraction (XRD) were used to study the coating microstructure, morphology and phase composition. The corrosion resistance of the coated and uncoated samples was examined by potentiodynamic polarization in a 3.5% NaCl solution. It was found that the plasma temperature profiles are significantly influenced by changing the current mode from unipolar to bipolar. The strongest discharges that are initiated at the interface between the substrate and the coating can be reduced or eliminated by using a bipolar current mode. This produces a thinner, denser and more corrosion-resistant coating.

Hussein, R.O., E-mail: husseinr@uwindsor.ca [Department of Mechanical, Automotive and Materials Engineering, University of Windsor, Windsor, ON, N9B 3P4 (Canada); Nie, X. [Department of Mechanical, Automotive and Materials Engineering, University of Windsor, Windsor, ON, N9B 3P4 (Canada); Northwood, D.O., E-mail: dnorthwo@uwindsor.ca [Department of Mechanical, Automotive and Materials Engineering, University of Windsor, Windsor, ON, N9B 3P4 (Canada)

2012-05-15

128

Electron transport behavior of individual zinc oxide coated single-walled carbon nanotubes  

Science.gov (United States)

Uniform zinc oxide coated single-walled nanotubes (SWNTs) were fabricated by ultrasonic irradiation with acid-treated SWNTs, zinc acetate, and triethanolamine at low temperature in aqueous phase processing. The ZnO coating process did not decrease the dark current of the SWNTs, but a real decrease in the steady state negative photocurrent was observed after ZnO coating, suggesting a clear photosensitization effect. Transport measurements reveal that the negative photocurrent in s (semiconducting)-SWNTs@ZnO could be described by electron-hole compensation behavior attributed to the ZnO layer under ultraviolet excitation. This simple coating method for one-dimensional material can open up new possibilities for multifunctional nanodevices.

Lin, Chin-Ching; Chu, Bryan T. T.; Tobias, Gerard; Sahakalkan, Serhat; Roth, Siegmar; Green, Malcolm L. H.; Chen, San-Yuan

2009-03-01

129

Adsorption and Desorption Mechanisms of Methylene Blue Removal with Iron-Oxide Coated Porous Ceramic Filter  

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Full Text Available Adsorption and desorption mechanisms of methylene blue (MB removal with iron-oxide coated porous ce-ramics filter (IOCPCF were investigated in batch and column mode. The results revealed that MB removal mechanisms included physical adsorption and chemical adsorption, of which chemical adsorption by surface ligand complex reaction played a dominant role after infrared spectrum analysis. Recycling agents were se-lected from dilute nitric acid (pH=3, sodium hydroxide solution (pH=12 and distilled water. Among three agents, dilute metric acid (pH=3 was the best recycling agent. Regeneration rate of IOCPCF arrived at 82.56% at batch adsorption and regeneration was finished in 75min at column adsorption. Adsorp-tion-desorption cycles of IOCPCF after batch and column adsorption were four and three times, respectively. Further, compared with fresh IOCPCF, MB removal rate with these desorbed IOCPCF adsorption only slightly decreased, which suggested that IOCPCF should be used repeatedly.

Songjiang MA

2009-05-01

130

Antibacterial properties and cytocompatibility of tantalum oxide coatings with different silver content  

International Nuclear Information System (INIS)

Tantalum (Ta) oxides and their coatings have been proved to increase their applications in the biomedical fields by improving osseointegration and wear resistance. In this study, Ta oxide coatings containing different proportions of Ag are deposited on SS304 materials. A twin-gun magnetron sputtering system is used to deposit the tantalum oxide-Ag coating. In this study, Staphylococcus aureus, which exhibits physiological commensalism on the human skin, nares, and mucosal and oral areas, is chosen as the model for in vitro antibacterial analyses via a fluorescence staining method using Syto9. The cytocompatibility and adhesive morphology of human skin fibroblast cells (CCD-966SK) on the coatings are also determined by using the microculture tetrazolium assay. This study shows that Ta2O5 and Ta2O5-Ag coatings with 12.5 at. % of Ag exhibit improved antibacterial effects against S. aureus and have good skin fibroblast cell cellular biocompatibility

131

Surface chemistry of metal oxide coated lithium manganese nickel oxide thin film cathodes studied by XPS  

International Nuclear Information System (INIS)

Highlights: ? LiMn1.5Ni0.5O4 spinel thin films were prepared by RF magnetron sputtering. ? The effect of thin metal oxide coatings on cycling and surface chemistry has been studied upon cycling by X-ray photoelectron spectroscopy. ? ZrO2 limits the available storage capacity. ZnO dissolves at potentials larger than 4.7 V vs. Li/Li+. Al2O3 is stable upon long cycling. ? Ethers, esters, LiF and LixPOyFz are the main constituents of the CEI surface layer. -- Abstract: The effect of coating the high voltage spinel cathode LiMn1.5Ni0.5O4 with three metal oxide thin layers is discussed. Instead of the typical powder electrodes with poorly defined surface coatings, thin film electrodes were prepared with well-defined oxide coating thicknesses to investigate the influence of coating on surface reactivity via X-ray photoelectron spectroscopy (XPS). ZnO is found to decompose during the first charge whereas Al2O3 and ZrO2 are stable for more than 100 cycles. ZrO2, however, importantly limits the available Li storage capacity of the electrochemical reaction due to poorer kinetics. Al2O3 offers the best results in term of capacity retention. Upon cycling, the evidence of a signal at 75.4 eV in the Al2p binding energy spectrum indicates the partial fluorination of Al2O3 into, perhaps, Al2O2F2. Moreover, the continuous formation of ethers, esters and LixPOyFz compounds on the surface of the electrodes is found for all coating materials

132

Superhydrophilicity and antibacterial property of a Cu-dotted oxide coating surface  

Directory of Open Access Journals (Sweden)

Full Text Available Abstract Background Aluminum-made settings are widely used in healthcare, schools, public facilities and transit systems. Frequently-touched surfaces of those settings are likely to harbour bacteria and be a potential source of infection. One method to utilize the effectiveness of copper (Cu in eliminating pathogens for these surfaces would be to coat the aluminum (Al items with a Cu coating. However, such a combination of Cu and Al metals is susceptible to galvanic corrosion because of their different electrochemical potentials. Methods In this work, a new approach was proposed in which electrolytic plasma oxidation (EPO of Al was used to form an oxide surface layer followed by electroplating of Cu metal on the top of the oxide layer. The oxide was designed to function as a corrosion protective and biocompatible layer, and the Cu in the form of dots was utilized as an antibacterial material. The antibacterial property enhanced by superhydrophilicity of the Cu-dotted oxide coating was evaluated. Results A superhydrophilic surface was successfully prepared using electrolytic plasma oxidation of aluminum (Al followed by electroplating of copper (Cu in a Cu-dotted form. Both Cu plate and Cu-dotted oxide surfaces had excellent antimicrobial activities against E. coli ATCC 25922, methicillin-resistant Staphylococcus aureus (MRSA ATCC 43300 and vancomycin-resistant Enterococcus faecium (VRE ATCC 51299. However, its Cu-dotted surface morphology allowed the Cu-dotted oxide surface to be more antibacterial than the smooth Cu plate surface. The enhanced antibacterial property was attributed to the superhydrophilic behaviour of the Cu-dotted oxide surface that allowed the bacteria to have a more effective killing contact with Cu due to spreading of the bacterial suspension media. Conclusion The superhydrophilic Cu-dotted oxide coating surface provided an effective method of controlling bacterial growth and survival on contact surfaces and thus reduces the risk of infection and spread of bacteria-related diseases particularly in moist or wet environments.

Nie Yining

2010-09-01

133

BACTERIOPHAGE PRD1 AND SILICA COLLOID TRANSPORT AND RECOVERY IN AN IRON OXIDE-COATED SAND AQUIFER. (R826179)  

Science.gov (United States)

Bacteriophage PRD1 and silica colloids were co-injected into sewage-contaminated and uncontaminated zones of an iron oxide-coated sand aquifer on Cape Cod, MA, and their transport was monitored over distances up to 6 m in three arrays. After deposition, the attache...

134

Nanostructured hydrophobic DC sputtered inorganic oxide coating for outdoor glass insulators  

Science.gov (United States)

We report the structural, optical and electrical properties of nanostructured hydrophobic inorganic hafnium oxide coating for outdoor glass insulator using DC sputtering technique to combat contamination problem. The properties were studied as a function of DC power. The characterization of the films was done using X-ray diffraction, EDS, surface profilometer, AFM, impedance analyser and water contact angle measurement system. The DC power was varied from 30 to 60 W and found to have a great impact on the properties of hafnium oxide. All the deposited samples were polycrystalline with nanostructured hydrophobic surfaces. The intensity of crystallinity of the film was found to be dependent on sputtering power and hydrophobicity was correlated to the nanoscale roughness of the films. The optical property reveals 80% average transmission for all the samples. The refractive index was found in the range of 1.85-1.92, near to the bulk value. The band gap calculated from transmission data was >5.3 eV for all deposited samples ensuring dielectric nature of the films. Surface energy calculated by two methods was found minimum for the film deposited at 50 W sputtering power. The resistivity was also high enough (˜104 ? cm) to hinder the flow of leakage current through the film. The dielectric constant (?) was found to be thickness dependent and also high enough (?max = 23.12) to bear the large electric field of outdoor insulators.

Dave, V.; Gupta, H. O.; Chandra, R.

2014-03-01

135

Stress controlled gas-barrier oxide coatings on semi-crystalline polymers  

International Nuclear Information System (INIS)

Thin silicon oxide (SiOx) barrier coatings formed by plasma enhanced chemical vapor deposition on poly(ethylene terephthalate) (PET) substrates were subjected to post-deposition annealing treatments in the temperature range for orientation relaxation of the polymer. The resulting change in coating internal stress state was measured by means of thermo-mechanical analyses, and its effect on the coating cohesive properties and coating/polymer adhesion was determined from the analysis of uniaxial fragmentation tests in situ in a scanning electron microscope, assuming a Weibull-type probability of failure and a perfectly plastic stress transfer at the SiOx/PET interface. The strain to failure and intrinsic fracture toughness of the ultrathin oxide coating were found to be as high as 5.7% and 10 J/m2, respectively, and its interfacial shear strength with PET was found to be close to 100 MPa. Annealing for 10 min at 150 deg. C did not modify the oxygen permeation properties of the SiOx/PET film, which suggests that the defect population of the oxide was not affected by the thermal treatment. In contrast, the coating internal compressive stress resulting from annealing was shown to increase by 40% the apparent coating cohesive properties and adhesion to the polymer

136

Antibacterial properties and cytocompatibility of tantalum oxide coatings with different silver content  

Energy Technology Data Exchange (ETDEWEB)

Tantalum (Ta) oxides and their coatings have been proved to increase their applications in the biomedical fields by improving osseointegration and wear resistance. In this study, Ta oxide coatings containing different proportions of Ag are deposited on SS304 materials. A twin-gun magnetron sputtering system is used to deposit the tantalum oxide-Ag coating. In this study, Staphylococcus aureus, which exhibits physiological commensalism on the human skin, nares, and mucosal and oral areas, is chosen as the model for in vitro antibacterial analyses via a fluorescence staining method using Syto9. The cytocompatibility and adhesive morphology of human skin fibroblast cells (CCD-966SK) on the coatings are also determined by using the microculture tetrazolium assay. This study shows that Ta{sub 2}O{sub 5} and Ta{sub 2}O{sub 5}-Ag coatings with 12.5 at. % of Ag exhibit improved antibacterial effects against S. aureus and have good skin fibroblast cell cellular biocompatibility.

Huang, Heng-Li [School of Dentistry, China Medical University, Taichung 404, Taiwan (China); Chang, Yin-Yu, E-mail: yinyu@mail2000.com.tw; Chen, Hung-Jui; Chou, Yu-Kai [Department of Mechanical and Computer-Aided Engineering, National Formosa University, Yunlin 632, Taiwan (China); Lai, Chih-Ho [School of Medicine, China Medical University, Taichung 404, Taiwan (China); Chen, Michael Y. C. [Division of Oral and Maxillofacial Surgery, China Medical University Hospital, Taichung 404, Taiwan (China)

2014-03-15

137

Antibacterial activity and cytocompatibility of titanium oxide coating modified by iron ion implantation.  

Science.gov (United States)

In this work, zero valent iron nanoparticles (Fezero-NPs) and iron oxide nanoparticles (Feox-NPs) were synthesized at the subsurface and surface regions of titanium oxide coatings (TOCs) by plasma immersion ion implantation. This novel Fe-NPs/TOC system showed negligible iron releasing, great electron storage capability and excellent cytocompatibility in vitro. Importantly, the system showed selective antibacterial ability which can kill Staphylococcus aureus under dark conditions but has no obvious antibacterial effect against Escherichia coli. Owing to a bipolar Schottky barrier between Fezero-NPs/TOC and Fezero-NPs/Feox-NPs, electrons could be captured by the Fezero-NPs bounded at the subsurface region of the coating. This electron storage capability of the Fe-NPs/TOC system induced extracellular electron transportation and accumulation of adequate valence-band holes (h(+)) at the external side, which caused oxidation damage to S. aureus cells in the dark. No obvious biocide effect against E. coli resulted from lack of electron transfer ability between E. coli and substrate materials. This work may open up a novel and controlled strategy to design coatings of implants with antibacterial ability and cytocompatibility for medical applications. PMID:24914826

Tian, Yaxin; Cao, Huiliang; Qiao, Yuqin; Meng, Fanhao; Liu, Xuanyong

2014-10-01

138

Physical properties of pyrolytically sprayed tin-doped indium oxide coatings  

Energy Technology Data Exchange (ETDEWEB)

The optical and electrical properties of tin-doped indium oxide coatings obviously depend on a number of production parameters. This dependence has been studied to obtain a more general insight into the relationships between the various coating properties. The coatings have been produced by spray pyrolysis using a solution of indium chloride in butylacetate with tin chloride as a dopant. The influence of the tin concentration, the carrier gas for the spraying, the coating thickness, the substrate temperature and annealing has been investigated using various techniques. The best result is obtained when producing a coating of about 300 nm thickness, using nitrogen as the carrier gas to prevent an excess of oxygen in the coating. When the tin doping is about 5%, the maximum density and mobility of the free electrons are obtained (about 5x10{sup 20} cm{sup -3} and 45 cm{sup 2}V{sup -1} s{sup -1} respectively). The substrate temperature has to be high; about 580degC in the case of glass substrates. The electrical and optical properties are satisfactorily described using the theory of ionized impurity scattering. The study of the relation between the structural and the electrical-optical properties shows that the structural properties, i.e. the crystallite size and orientation, influence the electrical and optical properties only weakly. (orig.).

Haitjema, H.; Elich, J.J.P. (Delft Univ. of Tech., Faculty of Applied Physics (Netherlands))

1991-10-30

139

Treatment and Kinetic of Synthetic Wastewater Containing ?-Naphthol by Nano Titanium Oxide Coated on Activated Carbon  

Directory of Open Access Journals (Sweden)

Full Text Available Background and Objectives: Many industrial effluent plants contain amounts of hard biodegradable compounds such as ?-naphthol which can be removed by conventional treatment systems. The objective of this research is to treat wastewater containing naphthalene by nano titanium oxide coated on activated carbon. Materials and Methods: Photocatalytic experiments were carried out for different concentrations of ?-naphthol using time and pH as dependent factors. Nano TiO2 coated on activated carbone in one liter batch reactor and the resultants compounds concentration were measured in a photocatalytic reactor  with UV-C of 12 Watt. Results: The experimental results indicated that UV/ nano TiO2 coated on activated carbone removed 92% of ?-naphthol with concentrations of 100 mg/L within an overall elapsed time of three hours. ?-naphthol total removal with concenteration of 25 mg/L was observed in two hours.Conclusions: UV/ nano TiO2 process is very fast and effective method for removal of ?-naphthol and  pH 11 was indicated as the optimum pH.

H Ijad panah

2012-03-01

140

Deuterium permeation through erbium oxide coatings on RAFM steels by a dip-coating technique  

Energy Technology Data Exchange (ETDEWEB)

A tritium permeation barrier is a promising solution for the problems of tritium loss and radiological safety in fusion blanket systems. In recent years, erbium oxide coatings have shown remarkable permeation reduction factors. One of the remaining issues for the coatings is the establishment of plant-scale fabrication. In this study, erbium oxide thin films have been fabricated by a dip-coating technique, which has the potential to coat a complex-shaped substrate, and deuterium permeation behavior in the coatings has been examined. Crack-free coatings were formed on a reduced activation ferritic/martensitic steel F82H substrate by use of a withdrawal speed of 1.0–1.4 mm s{sup ?1} and a heat-treatment process in hydrogen with moisture. In deuterium permeation experiments, a 0.2-?m-thick coating on both sides of the substrate showed a reduction factor of 600–700 in comparison with a F82H substrate below 873 K; however, the coating degraded at above 923 K because of crack formation. A double-coated sample indicated a reduction factor of up to 2000 and did not degrade at up to 923 K. The driving pressure dependence of the deuterium permeation flux indicated that the permeation tended to be limited by surface reactions at low temperatures. Optimization of the number of layers has the possibility to reduce degradation at high temperatures while maintaining high permeation reduction factors.

Chikada, Takumi, E-mail: chikada@nuclear.jp [Institute of Engineering Innovation, School of Engineering, The University of Tokyo, 2-11-16 Yayoi, Bunkyo-ku, Tokyo 113-8656 (Japan); Naitoh, Shunya [Department of Systems Innovation, Faculty of Engineering, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8656 (Japan); Suzuki, Akihiro [Nuclear Professional School, School of Engineering, The University of Tokyo, 2-22 Shirakata-shirane, Tokai, Naka, Ibaraki 319-1188 (Japan); Terai, Takayuki [Institute of Engineering Innovation, School of Engineering, The University of Tokyo, 2-11-16 Yayoi, Bunkyo-ku, Tokyo 113-8656 (Japan); Tanaka, Teruya; Muroga, Takeo [Fusion Systems Research Division, Department of Helical Plasma Research, National Institute for Fusion Science, 322-6 Oroshi, Toki, Gifu 509-5292 (Japan)

2013-11-15

 
 
 
 
141

Reduced bleaching in organic nanofibers by bilayer polymer/oxide coating  

International Nuclear Information System (INIS)

Para-hexaphenylene (p-6P) molecules exhibit a characteristic photoinduced reaction (bleaching) resulting in a decrease in luminescence intensity upon UV light exposure, which could render the technological use of the nanofibers problematic. In order to investigate the photoinduced reaction in nanofibers, optical bleaching experiments have been performed by irradiating both pristine and coated nanofibers with UV light. Oxide coating materials (SiOx and Al2O3) were applied onto p-6P nanofibers. These treatments caused a reduction in the bleaching reaction but in addition, the nanofiber luminescence spectrum was significantly altered. It was observed that some polymer coatings [a statistical copolymer of tetrafluoroethylene and 2,2-bis-trifluoromethyl-4,5-difluoro-1,3-dioxole, P(TFE-PDD), and poly(methyl methacrylate), PMMA] do not interfere with the luminescence spectrum from the p-6P but are not effective in stopping the bleaching. Bilayer coatings with first a polymer material, which should work as a protection layer to avoid modifications of the p-6P luminescence spectrum, and second an oxide layer used as oxygen blocker were tested and it was found that a particular bilayer polymer/oxide combination results in a significant reduction in bleaching without affecting significantly the emission spectrum from the nanofibers.

142

Wear resistance of micro-arc oxidation coatings on biomedical NiTi alloy  

Energy Technology Data Exchange (ETDEWEB)

Protective coatings were successfully formed on biomedical NiTi alloy by micro-arc oxidation (MAO) using pulsed bipolar power supply. The coating surface exhibits a typical MAO porous structure, and the coating mainly consists of O, Al, Ti and Ni, with the atomic concentration of 65.11%, 27.77%, 2.20% and 2.8%, respectively. The thickness of MAO coating is about 24.0 {mu}m when the duration time of the MAO treatment was 90 min at 400 V constant voltage treatment. XRD analysis showed that micro-arc oxidation coating is composed of {gamma}-Al{sub 2}O{sub 3} and {alpha}-Al{sub 2}O{sub 3}. The wear resistance of the coatings was investigated by ball-on-disk friction test. The microhardness of the NiTi alloy is greatly enhanced due to the formation of Al{sub 2}O{sub 3} coating after micro-arc oxidation treatment. The friction coefficient of the coated NiTi is stable at 0.85 and the wear resistance is increased by 9 times compared with uncoated NiTi. The wear mechanism transforms from abrasive-dominant for the uncoated sample to adhesive-dominant for the coated sample.

Liu, F., E-mail: ryuufuku@hotmail.co [School of Materials Science and Engineering, Harbin Institute of Technology, Harbin 150001 (China); Xu, J.L. [School of Materials Science and Engineering, Harbin Institute of Technology, Harbin 150001 (China); Yu, D.Z. [Stomatological Medicine Center, Harbin Institute of Technology, Harbin 150001 (China); Wang, F.P. [Department of Applied Chemistry, Harbin Institute of Technology, Harbin 150001 (China); Zhao, L.C. [School of Materials Science and Engineering, Harbin Institute of Technology, Harbin 150001 (China)

2009-11-13

143

Deuterium permeation through erbium oxide coatings on RAFM steels by a dip-coating technique  

Science.gov (United States)

A tritium permeation barrier is a promising solution for the problems of tritium loss and radiological safety in fusion blanket systems. In recent years, erbium oxide coatings have shown remarkable permeation reduction factors. One of the remaining issues for the coatings is the establishment of plant-scale fabrication. In this study, erbium oxide thin films have been fabricated by a dip-coating technique, which has the potential to coat a complex-shaped substrate, and deuterium permeation behavior in the coatings has been examined. Crack-free coatings were formed on a reduced activation ferritic/martensitic steel F82H substrate by use of a withdrawal speed of 1.0-1.4 mm s-1 and a heat-treatment process in hydrogen with moisture. In deuterium permeation experiments, a 0.2-?m-thick coating on both sides of the substrate showed a reduction factor of 600-700 in comparison with a F82H substrate below 873 K; however, the coating degraded at above 923 K because of crack formation. A double-coated sample indicated a reduction factor of up to 2000 and did not degrade at up to 923 K. The driving pressure dependence of the deuterium permeation flux indicated that the permeation tended to be limited by surface reactions at low temperatures. Optimization of the number of layers has the possibility to reduce degradation at high temperatures while maintaining high permeation reduction factors.

Chikada, Takumi; Naitoh, Shunya; Suzuki, Akihiro; Terai, Takayuki; Tanaka, Teruya; Muroga, Takeo

2013-11-01

144

Deuterium permeation through erbium oxide coatings on RAFM steels by a dip-coating technique  

International Nuclear Information System (INIS)

A tritium permeation barrier is a promising solution for the problems of tritium loss and radiological safety in fusion blanket systems. In recent years, erbium oxide coatings have shown remarkable permeation reduction factors. One of the remaining issues for the coatings is the establishment of plant-scale fabrication. In this study, erbium oxide thin films have been fabricated by a dip-coating technique, which has the potential to coat a complex-shaped substrate, and deuterium permeation behavior in the coatings has been examined. Crack-free coatings were formed on a reduced activation ferritic/martensitic steel F82H substrate by use of a withdrawal speed of 1.0–1.4 mm s?1 and a heat-treatment process in hydrogen with moisture. In deuterium permeation experiments, a 0.2-?m-thick coating on both sides of the substrate showed a reduction factor of 600–700 in comparison with a F82H substrate below 873 K; however, the coating degraded at above 923 K because of crack formation. A double-coated sample indicated a reduction factor of up to 2000 and did not degrade at up to 923 K. The driving pressure dependence of the deuterium permeation flux indicated that the permeation tended to be limited by surface reactions at low temperatures. Optimization of the number of layers has the possibility to reduce degradation at high temperatures while maintaining high permeation reduction factors

145

Corrosion behavior of oxide coated cold-rolled and electrogalvanized sheet steel  

International Nuclear Information System (INIS)

The authors studied the effects of sputtered oxide films on the corrosion and electrochemical behavior of cold-rolled (CRS) and electrogalvanized (EG) steel sheet. Films of Al2O3, TiO2, Ta2O5, and Cr2O3 were applied by off-axis dc magnetron sputter deposition. The films (deposited at 5 mTorr (0.667Pa), substrate temperature at about 50 C, and self-bias of -30 to -60 volts) were 1.2 to 4.0 micrometers thick and possessed an amorphous structure. The coated samples exhibit voltage-current behaviors similar to those of their substrates during polarization tests (at room temperature and 10 mV/min. scan rate) in aerated neutral 3.5% sodium chloride solution. Open-circuit potential (Ec) vs time was measured on coated CRS and EG samples for 21 hours continuously immersed in the solution. E, V(SCE) changed rapidly during the first two hours then gradually approached the substrate rest potential over the 24 hours. Pores were found in oxide films by scanning electron microscope examination of cross section and surface morphologies. Corrosion behaviors of painted, oxide-coated CRS and EG samples were determined by measurement of scribe creep in cyclic corrosion tests involving repeated exposure to alternating periods of wetness, drying, and salt water. These results are compared to those for both uncoated and conventionally phosphated substrates

146

Indium tin oxide coatings properties as a function of the deposition atmosphere  

Energy Technology Data Exchange (ETDEWEB)

Indium tin oxide coatings were deposited by magnetron sputtering physical vapour deposition under different atmospheres. Microstructural, electrical, and optical properties were measured, finding a correlation among properties and process parameters. Texture analyses carried out by X-ray diffraction showed that films microstructure depended by the oxygen content in the deposition vessel: high values of the oxygen content (e.g., 5%) caused the film to grow along the <111> orientation; under pure Ar, the grains grew along the <100> orientation. Intermediate values of the oxygen content caused the growth of two families of grains, respectively oriented along the <111> and the <100> directions. - Highlights: Black-Right-Pointing-Pointer Correlation between deposition atmosphere and indium tin oxide films properties Black-Right-Pointing-Pointer Resistivity and transmittance depended by the O2 content in the deposition vessel. Black-Right-Pointing-Pointer At high oxygen content, the films grew along the <111> direction. Black-Right-Pointing-Pointer At low oxygen content, the films grew along the <100> direction. Black-Right-Pointing-Pointer Intermediate oxygen contents allowed the growth of both the orientations.

Tului, Mario, E-mail: m.tului@c-s-m.it [Centro Sviluppo Materiali S.p.A., Via di Castel Romano, 100, 00128 Rome Italy (Italy); Bellucci, Alessandra, E-mail: a.bellucci@c-s-m.it [Centro Sviluppo Materiali S.p.A., Via di Castel Romano, 100, 00128 Rome Italy (Italy); Bellini, Stefania, E-mail: s.bellini@c-s-m.it [Centro Sviluppo Materiali S.p.A., Via di Castel Romano, 100, 00128 Rome Italy (Italy); Albolino, Augusto, E-mail: aalbolino@alenia.it [Alenia Aermacchi S.p.A., Viale dell' Aeronautica, snc, 80038 Pomigliano d' Arco, Naples (Italy); Migliozzi, Giuseppe, E-mail: gmigliozzi@alenia.it [Alenia Aermacchi S.p.A., Corso Marche 41, 10146 Torino Italy (Italy)

2012-03-30

147

Selection of a Commercial Anode Oxide Coating for Electro-oxidation of Cyanide  

Scientific Electronic Library Online (English)

Full Text Available SciELO Brazil | Language: English Abstract in portuguese Este trabalho apresenta um estudo do desempenho de dois anodos comerciais de óxidos de metais nobres (DSA®) no processo eletroquímico para a oxidação de cianetos. Os revestimentos estudados foram 70TiO2/30RuO2 e 55Ta2O5/45IrO2, em um substrato de Ti. A eficiência dos dois materiais no processo de el [...] etrooxidação de cianeto livre foi comparada usando a voltametria linear e a eletrólise a potencial constante. O eletrodo 70TiO2/30RuO2 apresentou a melhor eficiência na eletrooxidação de cianetos livres. Abstract in english This paper presents a study of the performance of two commercial dimensionally stable anode (DSA®) oxide coatings in the electrochemical process for cyanide oxidation. The coatings studied were 70TiO2/30RuO2 and 55Ta2O5/45IrO2, on Ti substrate. The efficiency of both materials in the electro-oxidati [...] on of free cyanide was compared using linear voltammetry and electrolysis at constant potential. The 70TiO2/30RuO2 electrode shows a better performance in the electro-oxidation of free cyanide.

Marcos Roberto V., Lanza; Rodnei, Bertazzoli.

148

Influence of substrate additives on the mechanical properties of ultrathin oxide coatings on poly(ethylene terephthalate)  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The mechanical properties of ultrathin silicon oxide (SiOx) coatings plasma-deposited on poly(ethylene terephthalate) (PET) films were investigated with particular attention paid to the effect of additives located in the superficial layers of the polymer substrate. The cohesive and adhesive properties of the thin oxide coating were derived from the analysis of fragmentation tests carried out in situ in a scanning electron microscope. The cohesive strength of the coating was determined assumin...

Rochat, G.; Leterrier, Y.; Fayet, P.; Manson, J. A. E.

2005-01-01

149

Removal of dissolved heavy metals from pre-settled stormwater runoff by iron-oxide coated sand (IOCS)  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Sorption to iron-oxide coated sand (IOCS) is a promosing technology for removal of the dissolved heavy metal fraction in stormwater runoff. The development of a new technology is necessary since studies of stormwater runoff from traffic areas indicate that an oil separator and detention pond may not guarantee that emission limit values set by the Danish EPA are satisfied. Runoff water was sampled from an urban highway, allowed to settle for 24 hours to simulate the effect of a detention pond,...

Møller, J.; Ledin, Anna; Mikkelsen, Peter Steen

2006-01-01

150

Synthesis of iron oxide coated fluoridated HAp/Ln(3+) (Ln = Eu or Tb) nanocomposites for biological applications.  

Science.gov (United States)

Fluorescent-magnetic iron oxide coated fluoridated HAp/Ln(3+) (Ln = Eu or Tb) nanocomposites were prepared. After transforming hydrophobic fluoridated HAp/Ln(3+) nanorods into hydrophilic ones, iron oxide particles were coated on their surface via thermal decomposition of Fe(acac)3. Fluorescent-magnetic nanocomposites developed in this study demonstrate excellent fluorescent-magnetic properties and prominent biocompatibility. PMID:25267372

Pan, Jie; Zhang, Juchen; Wang, Lili; Wan, Dong

2014-10-16

151

Zn Sorption Mechanisms onto Sheathed Leptothrix Discophora and the Impact of the Nanoparticulate Biogenic Mn Oxide Coating  

Energy Technology Data Exchange (ETDEWEB)

Zinc sorption on sheathed Leptothrix discophora bacterium, the isolated extracellular polymeric substances (EPS) sheath, and Mn oxide-coated bacteria was investigated with macroscopic and spectroscopic techniques. Complexation with L. discophora was dominated by the outer membrane phosphoryl groups of the phospholipid bilayer while sorption to isolated EPS was dominated by carboxyl groups. Precipitation of nanoparticulate Mn oxide coatings on the cell surface increased site capacity by over twenty times with significant increase in metal sorption. XAS analysis of Zn sorption in the coated system showed Mn oxide phase contributions of 18 to 43% through mononuclear inner-sphere complexes. The coordination environments in coprecipitation samples were identical to those of sorption samples, indicating that, even in coprecipitation, Zn is not incorporated into the Mn oxide structure. Rather, through enzymatic oxidation by L. discophora, Mn(II) is oxidized and precipitated onto the biofilm providing a large surface for metal sequestration. The nanoparticulate Mn oxide coating exhibited significant microporosity (75%) suggesting contributions from intraparticle diffusion. Transient studies conducted over 7 months revealed a 170% increase in Zn loading. However, the intraparticle diffusivity of 10{sup -19} cm{sup 2} s{sup -1} is two orders of magnitude smaller than that for abiotic Mn oxide which we attribute to morphological changes such as reduced pore sizes in the nanoparticulate oxide. Our results demonstrate that the cell-bound Mn oxide particles can sorb significant amounts of Zn over long periods of time representing an important surface for sequestration of metal contaminants.

Boonfueng, T.; Axe, L; Yee, N; Hahn, D; Ndiba, P

2009-01-01

152

Zn sorption mechanisms onto sheathed Leptothrix discophora and the impact of the nanoparticulate biogenic Mn oxide coating.  

Science.gov (United States)

Zinc sorption on sheathed Leptothrix discophora bacterium, the isolated extracellular polymeric substances (EPS) sheath, and Mn oxide-coated bacteria was investigated with macroscopic and spectroscopic techniques. Complexation with L. discophora was dominated by the outer membrane phosphoryl groups of the phospholipid bilayer while sorption to isolated EPS was dominated by carboxyl groups. Precipitation of nanoparticulate Mn oxide coatings on the cell surface increased site capacity by over twenty times with significant increase in metal sorption. XAS analysis of Zn sorption in the coated system showed Mn oxide phase contributions of 18 to 43% through mononuclear inner-sphere complexes. The coordination environments in coprecipitation samples were identical to those of sorption samples, indicating that, even in coprecipitation, Zn is not incorporated into the Mn oxide structure. Rather, through enzymatic oxidation by L. discophora, Mn(II) is oxidized and precipitated onto the biofilm providing a large surface for metal sequestration. The nanoparticulate Mn oxide coating exhibited significant microporosity (75%) suggesting contributions from intraparticle diffusion. Transient studies conducted over 7 months revealed a 170% increase in Zn loading. However, the intraparticle diffusivity of 10(-19) cm(2) s(-1) is two orders of magnitude smaller than that for abiotic Mn oxide which we attribute to morphological changes such as reduced pore sizes in the nanoparticulate oxide. Our results demonstrate that the cell-bound Mn oxide particles can sorb significant amounts of Zn over long periods of time representing an important surface for sequestration of metal contaminants. PMID:19268965

Boonfueng, Thipnakarin; Axe, Lisa; Yee, Nathan; Hahn, Dittmar; Ndiba, Peter K

2009-05-15

153

PENGARUH KOMPOSOSI LAPISAN PADA PERMUKAAN GLOBULA MINYAK EMULSI SEBELUM PENGERINGAN SEMPROT TERHADAP SIFAT-SIFAT MIKROKAMSUL TRIGLISERIDA KAYA ASAM LEMAK W-3 [The Effect of the Composition of Adsorbed Layer at Globule Interface of ?-3 Fatty Acids Enriched Triglyceride Prior to Spray Drying on its Microcapsule Properties  

Directory of Open Access Journals (Sweden)

Full Text Available Emulsification is the critical factor in microencapsulation by spray drying method. Sodium caseinate is a protein with good emulsifying properties. The properties could be improved by phospholipids addition in the emulsification. Phospholipids addition which stabilized oil globule might change the composition of adsorbed layer.This research was conducted to analyze the changes in composition at oil globule interface by analyzing emulsion systems of triglyceride enriched by ?-3 fatty acids at 5% (w/v stabilized by sodium caseinate (10% w/v and addition of phospholipids at 0; 0,5; 1,0; 1,5; 2,0; and 2,5% (w/v. The changes in composition of adsorbed layer could be determined from the changes in phospholipids and adsorbed protein concentrations at oil globule interface. Analyses were done to measure the possibility of casein-phospholipids complex, phospholipids and protein adsorption concentration at interface, and adsorbed protein.The increase of phospholipids concentration in the emulsions stabilized by sodium caseinate changed the composition of adsorbed layer at interface. There was phospholipids increase and adsorbed protein decrease at oil globule interface. These changes were caused by casein-phospholipids complex which that decreased surface activity and displacement protein by phospholipids that was adsorbed at oil globule interface.Changes of composition of casein-phospholipids at oil globule prior to microcapsulation process caused changes in the properties of microcapsule produced. The increasing phospholipids and decreasing casein concentrations at oil globule interface decreased the quality of the microcapsule, including decreasing in microencapsulation efficiency, in oxidative stability, and decreasing in EPA+DHA content.

Moch Adnan2

2005-04-01

154

Reduced bleaching in organic nanofibers by bilayer polymer/oxide coating  

DEFF Research Database (Denmark)

Organic semiconductors based on small molecules are receiving increased attention due in part to their application potential within various opto-electronic devices such as transistors, light-emitting diodes, and solar cells, but also due to their relative ease of processing, low price, and tunability through synthetic chemistry. Phenylene-based molecules such as para-hexaphenylene (p6P) are of particular interest due to their ability to self-assemble into elongated, nanoscale, crystalline aggregates or ‘nanofibers’ [1]. Such nanofibers can emit polarized light with a highly anisotropic emission profile, can act a sub-wavelength optical waveguides, and could form the basis for a new type of miniature OLEDs. However, p6P molecules exhibit a characteristic photoinduced reaction (bleaching) resulting in a decrease of luminescence intensity upon UV light exposure [2], which could render the technological use of the nanofibers problematic. In order to investigate the photoinduced reaction in nanofibers, optical bleaching experiments have been performed by irradiating both pristine and coated nanofibers with UV light. Oxide coating materials (SiOx [2] and Al2O3) were applied onto p6P nanofibers. These treatments caused a reduction of the bleaching reaction but in addition, the nanofiber luminescence spectrum was significantly altered. It was observed that some polymer coatings (P(TFE-PDD), and PMMA) do not interfere with the luminescence spectrum from the p6P but are not effective in stopping the bleaching. Bilayer coatings with first a polymer material, which should work as a protection layer to avoid modifications of the p6P luminescence spectrum, and second an oxide layer used as oxygen blocker were tested and it was found that a particular bilayer polymer/oxide combination results in a significant reduction of bleaching without affecting significantly the emission spectrum from the nanofibers.

Tavares, Luciana; Kjelstrup-Hansen, Jakob

155

Structural, electrochemical and optical comparisons of tungsten oxide coatings derived from tungsten powder-based sols  

Energy Technology Data Exchange (ETDEWEB)

Tungsten trioxide (WO{sub 3}) electrochromic coatings have been formed on indium tin oxide-coated glass substrates by aqueous routes. Coating sols are obtained by dissolving tungsten powder in acetylated (APTA) or plain peroxotungstic acid (PTA) solutions. The structural evolution and electrochromic performance of the coatings as a function of calcination temperature (250 {sup o}C and 400 {sup o}C) have been reported. Differential scanning calorimetry and X-ray diffraction have shown that amorphous WO{sub 3} films are formed after calcination at 250 {sup o}C for both processing routes; however, the coatings that calcined at 400 {sup o}C were crystalline in both cases. The calcination temperature-dependent crystallinity of the coatings results in differences in optical properties of the coatings. Higher coloration efficiencies can be achieved with amorphous coatings than could be seen in the crystalline coatings. The transmittance values (at 800 nm) in the colored state are 35% and 56% for 250 {sup o}C and 400 {sup o}C-calcined coatings, respectively. The electrochemical properties are more significantly influenced by the method of sol preparation. The ion storage capacities designating the electrochemical properties are found in the range of 1.62-2.74 x 10{sup -3} (mC cm{sup -2}) for APTA coatings; and 0.35-1.62 x 10{sup -3} (mC cm{sup -2}) for PTA coatings. As a result, a correlation between the microstructure and the electrochromic performance has been established.

Isik, Dilek, E-mail: e145342@metu.edu.t [Department of Metallurgical and Materials Engineering, METU, 06531 Ankara (Turkey); Ak, Metin, E-mail: metinak@pamukkale.edu.t [Department of Chemistry, Pamukkale University, 20017 Denizli (Turkey); Durucan, Caner, E-mail: cdurucan@metu.edu.t [Department of Metallurgical and Materials Engineering, METU, 06531 Ankara (Turkey)

2009-11-02

156

Electrolytic trichloroethene degradation using mixed metal oxide coated titanium mesh electrodes.  

Science.gov (United States)

Electrochemical systems provide a low cost, versatile, and controllable platform to potentially treat contaminants in water, including chlorinated solvents. Relative to bare metal or noble metal amended materials, dimensionally stable electrode materials such as mixed metal oxide coated titanium (Ti/MMO) have advantages in terms of stability and cost, important factors for sustainable remediation solutions. Here, we report the use of Ti/MMO as an effective cathode substrate for treatment of trichloroethene (TCE). TCE degradation in a batch reactor was measured as the decrease of TCE concentration over time and the corresponding evolution of chloride; notably, this occurred without the formation of commonly encountered chlorinated intermediates. The reaction was initiated when Ti/MMO cathode potentials were less than -0.8 V vs. the standard hydrogen electrode, and the rate of TCE degradation increased linearly with progressively more negative potentials. The maximum pseudo-first-order heterogeneous rate constant was approximately 0.05 cm min(-1), which is comparable to more commonly used cathode materials such as nickel. In laboratory-scale flow-though column reactors designed to simulate permeable reactive barriers (PRBs), TCE concentrations were reduced by 80-90%. The extent of TCE flux reduction increased with the applied potential difference across the electrodes and was largely insensitive to the spacing distance between the electrodes. This is the first report of the electrochemical reduction of a chlorinated organic contaminant at a Ti/MMO cathode, and these results support the use of this material in PRBs as a possible approach to manage TCE plume migration. PMID:17234239

Petersen, Matthew A; Sale, Thomas C; Reardon, Kenneth F

2007-04-01

157

Adsorption of phosphoric acid on niobium oxide coated cellulose fiber: preparation, characterization and ion exchange property  

International Nuclear Information System (INIS)

The preparation procedures for a hybrid organic-inorganic cellulose-niobium oxide (Cel/Nb2O5) and its derivative, Cel/Nb2O5/phosphate, are described. The precursor reagent of the metal oxide was the very convenient water soluble niobium oxalate compound, NH4[NbO(C2O4)2)(H2O)2].nH2 O. Phosphate ion was adsorbed on the Cel/Nb2O5 by immersing this solid in an aqueous solution of phosphoric acid. Textural analyses carried out by using scanning electron microscopy (SEM) connected to an energy dispersive detector (EDS) revealed that the niobium oxide particles are, within the magnification used, uniformly dispersed on the cellulose matrix surface. Phosphoric acid is adsorbed on the material surface through the Nb-O-P linkage. The X-ray photoelectron and 31P NMR spectra showed that the adsorbed phosphate on the surface is the (H2PO4)- species. The ion exchange isotherms obtained using the material Cel/Nb2O5/H2PO4- showed good affinity for retaining Na+, K+ and Ca2+ when in contact with these ions in an aqueous solution. (author)

158

Electrochemical investigation of chromium oxide-coated Ti-6Al-4V and Co-Cr-Mo alloy substrates.  

Science.gov (United States)

Hard coatings for articulating surfaces of total joint replacements may improve the overall wear resistance. However, any coating approach must take account of changes in corrosion behavior. This preliminary assessment analyzes the corrosion kinetics, impedance and mechanical-electrochemical stability of 100 ?m thick plasma sprayed chromium oxide (Cr?O?) coatings on bearing surfaces in comparison to the native alloy oxide films on Co-Cr-Mo and Ti-6Al-6V. Cyclic potentiodynamic polarization, electrochemical impedance spectroscopy, and mechanical abrasion under potentiostatic conditions were performed on coated and substrate surfaces in physiological saline. SEM analysis characterized the coating morphology. The results showed that the corrosion current density values of chromium oxide coatings (0.4-1.2 ?A/cm²) were of the same order of magnitude as Ti-6Al-4V alloy. Mechanical abrasion did not increase corrosion rates of chromium oxide coatings but did for uncoated Co-Cr-Mo and Ti-6Al-4V. The impedance response of chromium oxide coatings was very different than Co-Cr-Mo and Ti-6Al-4V native oxides characterized by a defected coating model. More of a frequency-independent purely resistive response was seen in mid-frequency range for the coatings (CPE(coat) : 40-280 nF/cm² (rad/s)(1-?) , ?: 0.67-0.83) whereas a more capacitive character is seen for Co-Cr-Mo and Ti-6Al-4V (CPE(ox) around 20 ?F/cm² (rad/s)(1-?) , ? around 0.9). Pores, interparticle gaps and incomplete fusion typical for thermal spray coatings were present in these oxides which could have influenced corrosion resistance. The coating microstructure could have allowed some fluid penetration. Overall, these coatings appear to have suitable corrosion properties for wear surfaces. PMID:21648063

Swaminathan, Viswanathan; Zeng, Haitong; Lawrynowicz, Daniel; Zhang, Zongtao; Gilbert, Jeremy L

2011-08-01

159

Thermal and chemical stability studies of protective plasma sprayed yttrium oxide coatings on tantalum substrate against liquid uranium  

International Nuclear Information System (INIS)

Yttrium oxide was deposited on tantalum substrates (40 mm x 8 mm x 1 mm thk) by atmospheric plasma spray technique with out any bond coat using optimized coating parameters. Resistance to thermal shock was evaluated upto 6 cycles prior to the chemical compatibility experiments. Thermal shock qualified batch of coupons were tested for compatibility against liquid uranium at 1573 K upto 200 hrs in oxide coating exhibits excellent corrosion resistance vacuum. Experimental results show that yttrium against liquid uranium at 1573 K. (author)

160

The impact of the mass density on selected optical and non-optical properties of oxide coatings  

Science.gov (United States)

The density of optical coatings is one of the most crucial material-related parameters in interference coating science and technology. It has an impact on the refractive index, the transparency range, and the mechanical stress of a coating material. This tutorial provides a background on the classical theory relating the coating density to the mentioned parameters. Simple models are presented that highlight the correlations between optical constants, stress, and shifting behavior of different oxide coatings. Comparison with the experiment is performed on the basis of numerous experimental data, which stem from hafnium oxide, zirconium oxide, tantalum pentoxide, and silicon dioxide.

Stenzel, Olaf

2014-02-01

 
 
 
 
161

Regenerative adsorbent heat pump  

Science.gov (United States)

A regenerative adsorbent heat pump process and system is provided which can regenerate a high percentage of the sensible heat of the system and at least a portion of the heat of adsorption. A series of at least four compressors containing an adsorbent is provided. A large amount of heat is transferred from compressor to compressor so that heat is regenerated. The process and system are useful for air conditioning rooms, providing room heat in the winter or for hot water heating throughout the year, and, in general, for pumping heat from a lower temperature to a higher temperature.

Jones, Jack A. (Inventor)

1991-01-01

162

Investigation of structure and porosity of natural clayey adsorbents  

International Nuclear Information System (INIS)

The purpose of present work is investigation of structure and porosity of natural adsorbents. As investigation objects was chosen three clayey examples which on chemical composition are closed to montmorillonite

163

Di(isothiocyanatobis(4-methyl-4’-vinyl-2,2’-bipyridine Ruthenium(II Films Deposited on Titanium Oxide-Coated, Fluorine-Doped Tin Oxide for an Efficient Solar Cell  

Directory of Open Access Journals (Sweden)

Full Text Available Dye-sensitized titanium oxide electrodes were prepared by immobilizing a novel ruthenium complex, di(isothiocy- anatobis(4-methyl-4’-vinyl-2,2’-bipyridineruthenium(II [(NCS2(mvbpy2Ru(II] or the ruthenium complex/sodium 4-vinylbenzenesulfonate onto the surface of a titanium oxide-coated, fluorine-doped tin oxide (TiO2/FTO electrode through a new electrochemically initiated film formation method, in which the electrolysis step and the film deposition step were individually performed. The incident photon-to-current conversion efficiency (IPCE of the Ru complex film on a TiO2/FTO electrode was disappointedly insufficient (1.2% at 440 nm. In sharp contrast, the Ru(II complex/so- dium 4-vinylbenzenesulfonate composite film deposited on the surface of a TiO2/FTO electrode showed maximum IPCE of 31.7% at 438 nm.

Yi Liu

2013-05-01

164

Microstructure control and deuterium permeability of erbium oxide coating on ferritic/martensitic steels by metal-organic decomposition  

International Nuclear Information System (INIS)

The development of a tritium permeation barrier is essential for building a tritium recovery system in fusion power plants. Toward realizing this application, the fabrication of erbium oxide coatings by metal-organic decomposition has been carried out on reduced activation ferritic/martensitic steels. The coated samples exhibit different surface structures after they are heat-treated under different conditions. A sample that is heat-treated in high-purity argon produces an oxide layer between the erbium oxide coating and the substrate. It is believed that the presence of this oxide layer causes defects in the coating and degradation of the samples during deuterium permeation measurements. The sample heat-treated in high-purity hydrogen with moisture exhibits a thinner oxide layer and improved stability during measurements. A 0.3-?m-thick coating yields a permeation reduction factor of 500-700 at 773-973 K, which is comparable to the coating deposited by the physical vapor deposition technique.

165

Transporting method for adsorbing tower and the adsorbing tower  

International Nuclear Information System (INIS)

A cylindrical plastic bag is disposed to the upper surface of an adsorbing tower so as to surround a suspending piece. One opening of the bag is sealed, and other opening is secured in a sealed state to a bag holding portion disposed to glove box at a gate for the adsorbing tower box. The adsorbing tower is transported into the glove box, and after the completion of the operation of the adsorbing tower, the adsorbing tower is taken out in a state that the bag is restricted and sealed at a portion below the adsorbing tower. The bag may be made of a vinyl plastic, the bag holding portion may be a short-cylindrical protrusion, and may have an O-ring groove at the outer surface. Even if the adsorbing tower is heavy, the adsorbing tower can be carried out easily in a state where it is sealed gas tightly. (N.H.)

166

Adsorbent and adsorbent bed for materials capture and separation processes  

Science.gov (United States)

A method device and material for performing adsorption wherein a fluid mixture is passed through a channel in a structured adsorbent bed having a solid adsorbent comprised of adsorbent particles having a general diameter less than 100 um, loaded in a porous support matrix defining at least one straight flow channel. The adsorbent bed is configured to allow passage of a fluid through said channel and diffusion of a target material into said adsorbent under a pressure gradient driving force. The targeted molecular species in the fluid mixture diffuses across the porous support retaining layer, contacts the adsorbent, and adsorbs on the adsorbent, while the remaining species in the fluid mixture flows out of the channel.

Liu, Wei (Richland, WA)

2011-01-25

167

Size selective hydrophobic adsorbent for organic molecules  

Science.gov (United States)

The present invention relates to an adsorbent formed by the pyrolysis of a hydrophobic silica with a pore size greater than 5 .ANG., such as SILICALITE.TM., with a molecular sieving polymer precursor such as polyfurfuryl alcohol, polyacrylonitrile, polyvinylidene chloride, phenol-formaldehyde resin, polyvinylidene difluoride and mixtures thereof. Polyfurfuryl alcohol is the most preferred. The adsorbent produced by the pyrolysis has a silicon to carbon mole ratio of between about 10:1 and 1:3, and preferably about 2:1 to 1:2, most preferably 1:1. The pyrolysis is performed as a ramped temperature program between about 100.degree. and 800.degree. C., and preferably between about 100.degree. and 600.degree. C. The present invention also relates to a method for selectively adsorbing organic molecules having a molecular size (mean molecular diameter) of between about 3 and 6 .ANG. comprising contacting a vapor containing the small organic molecules to be adsorbed with the adsorbent composition of the present invention.

Sharma, Pramod K. (Inventor); Hickey, Gregory S. (Inventor)

1997-01-01

168

Adsorption of phosphoric acid on niobium oxide coated cellulose fiber: preparation, characterization and ion exchange property  

Scientific Electronic Library Online (English)

Full Text Available SciELO Brazil | Language: English Abstract in portuguese Os procedimentos para a preparação do híbrido orgânico-inorgânico celulose-óxido de nióbio (Cel/Nb2O5) e o seu derivado, Cel/Nb2O5/fosfato, são descritos. O reagente precursor do óxido metálico foi o composto oxalato de nióbio, NH4[NbO(C2O4)2)(H 2O)2].nH2 O, muito conveniente por ser solúvel em água [...] . O íon fostato foi adsorvido sobre o Cel/Nb2O5 pela imersão deste sólido em uma solução de acido fosfórico. As análises de textura efetuadas usando a microscopia eletrônica de varredura (MEV) conectada a um detector de energia dispersiva (EDS) revelaram que as partículas do óxido de nióbio, dentro da resolução utilizada, são uniformemente dispersas na superfície da matriz de celulose. O ácido fosfórico é adsorvido sobre a superfície do material através da formação da ligação Nb-O-P. Os espectros de fotoelétrons de raios-X e de ressonância magnética nuclear de 31P mostraram que o fosfato adsorvido na superfície é a espécie H2PO4-. As isotermas de troca iônica obtidas utilizando-se o material mostraram uma boa afinidade na retenção de Na+, K+ e Ca2+ quando em contacto com estes íons em solução aquosa. Abstract in english The preparation procedures for a hybrid organic-inorganic cellulose-niobium oxide (Cel/Nb2O5) and its derivative, Cel/Nb2O5/phosphate, are described. The precursor reagent of the metal oxide was the very convenient water soluble niobium oxalate compound, NH4[NbO(C2O4)2)(H 2O)2].nH2 O. Phosphate ion [...] was adsorbed on the Cel/Nb2O5 by immersing this solid in an aqueous solution of phosphoric acid. Textural analyses carried out by using scanning electron microscopy (SEM) connected to an energy dispersive detector (EDS) revealed that the niobium oxide particles are, within the magnification used, uniformly dispersed on the cellulose matrix surface. Phosphoric acid is adsorbed on the material surface through the Nb-O-P linkage. The X-ray photoelectron and 31P NMR spectra showed that the adsorbed phosphate on the surface is the (H2PO4)- species. The ion exchange isotherms obtained using the material Cel/Nb2O5/H2PO4- showed good affinity for retaining Na+, K+ and Ca2+ when in contact with these ions in an aqueous solution.

Flávio A., Pavan; Maria Suzana P., Francisco; Richard, Landers; Yoshitaka, Gushikem.

169

Orientational epitaxy in adsorbed monolayers  

International Nuclear Information System (INIS)

The ground state for adsorbed monolayers on crystalline substrates is shown to involve a definite relative orientation of the substrate and adsorbate crystal axes, even when the relative lattice parameters are incommensurate. The rotation angle which defines the structure of the monolayer-substrate system is determined by the competition between adsorbate-substrate and adsorbate-adsorbate energy terms, and is generally not a symmetry angle. Numerical predictions are presented for the rare gas-graphite systems, whose interaction potentials are rather well known. Recent LEED data for some of these systems appear to corroborate these predictions

170

Electron-microscopic imaging of electrolytic oxide coatings on AA2214; Elektronenmikroskopische Darstellung elektrolytischer Oxidschichten auf AA2214  

Energy Technology Data Exchange (ETDEWEB)

The alloy AA2214 is one of the medium to high-strength age-hardening forging alloys which play an important role as structural materials in the aircraft industry. For purposes of protection against corrosion and wear these alloys are very often anodized. Transmission electron microscopic studies on coatings anodized by sulfuric acid have clearly shown the effect of anodizing voltage on pore size. Intermetallic phases occurring in the microstructures of such materials were shown to be largely broken up during the anodizing process. Small proportions of alloy elements were, however, still detectable in the oxide. During the subsequent sealing process these open pores are closed and after only 15 minutes the process is substantially completed, revealing no significant gradation of density throughout the thickness of the oxide coating. (orig.)

Schneider, Michael [Fraunhofer-Institut fuer Keramische Technologien und Systeme (IKTS), Dresden (Germany); Kuebel, Christian; Yezerska, Olga [Fraunhofer Institut fuer Fertigungstechnik und Angewandte Materialforschung (IFAM), Bremen (Germany); Viola, Alain; Augros, Myriam [Messier-Bugatti, Molsheim (France). Div. Freinage Aeronautic

2009-05-15

171

Effect of substrate crystalline morphology on the adhesion of plasma enhanced chemical vapor deposited thin silicon oxide coatings on polyamide  

Science.gov (United States)

The influence of the surface morphology of semicrystalline polyamide 12 (PA12) on the adhesion of thin silicon oxide coatings is analyzed by means of uniaxial fragmentation tests and scanning local-acceleration microscopy (SLAM). Two types of PA12 substrates are investigated, namely, as-received PA12, which contains large spherulites, and quenched PA12, which has a relatively smooth, homogeneous surface structure. The adhesion of the coating is found to be identical for the two types of PA12. This indicates that plasma deposition of the oxide leads to an equivalent functionalization of the two types of surfaces. Nonetheless, localized delamination is observed at spherulite boundaries, and is argued to result from strain concentrations in the corresponding soft zones, revealed by SLAM measurements.

Rochat, G.; Leterrier, Y.; Plummer, C. J. G.; Mânson, J.-A. E.; Szoszkiewicz, R.; Kulik, A. J.; Fayet, P.

2004-05-01

172

Alloy Films Deposited by Electroplating as Precursors for Protective Oxide Coatings on Solid Oxide Fuel Cells Metallic Interconnect Materials  

Energy Technology Data Exchange (ETDEWEB)

The successful development of stainless steel interconnects for intermediate temperature solid oxide fuel cells (SOFC) may be the materials breakthrough that makes SOFC technology truly commercial. Many of the ferritic stainless steels, however, suffer from a relatively high area specific resistance (ASR) after long exposure times at temperature and the Cr in the native oxide can evaporate and contaminate other cell components. Conductive coatings that resist oxide scale growth and chromium evaporation may prevent both of these problems. In the present study electrochemical deposition of binary alloys followed by oxidation of the alloy to form protective and conductive oxide layers is examined. Results are presented for the deposition of Mn/Co and Fe/Ni alloys via electroplating to form a precursor for spinel oxide coating formation. Analysis of the alloy coatings is done by SEM, EDS and XRD.

Johnson, Christopher; Gemmen, R.S.; Cross, Caleb

2006-10-01

173

Fabrication of mesoporous metal oxide coated-nanocarbon hybrid materials via a polyol-mediated self-assembly process.  

Science.gov (United States)

After clarifying the formation mechanism of a typical metal glycolate precipitate, Ti glycolate, in a polyol-mediated synthesis using acetone as a precipitation medium, we describe a simple template-free approach based on an ethylene glycol-mediated synthesis to fabricate mesoporous metal oxide coated-nanocarbon hybrid materials including TiO2 coated-carbon nanotube (CNT), SnO2 coated-CNT, Cu2O/CuO coated-CNT and TiO2 coated-graphene sheet (GS). In the approach, metal oxide precursors, metal glycolates, were first deposited on CNTs or GSs, and subsequently transformed to the metal oxide coatings by pyrolysis or hydrolysis. By a comparison between the characterization of two TiO2-CNT hybrid materials using carboxylated CNTs and pristine CNTs without carboxyl groups, the driving force for initiating the deposition of metal glycolates on the carboxylated CNTs is confirmed to be the hydrogen bonding between the carboxyl groups and the polymer chains in metal glycolate sols. The electrochemical performances of the mesoporous TiO2 coated-carboxylated CNTs and TiO2-pristine CNT hybrid materials were investigated. The results show that the mesoporous TiO2 coated-carboxylated CNT with a uniform core-shell nanostructure exhibits substantial improvement in the rate performance in comparison with its counterpart from 0.5 C to 100 C because of its higher electronic conductivity and shorter diffusion path for the lithium ion. At the extremely high rate of 100 C, the specific capacity of TiO2 of the former reaches 85 mA h g(-1), twice as high as that of the latter. PMID:25329525

Feng, Bingmei; Wang, Huixin; Wang, Dongniu; Yu, Huilong; Chu, Yi; Fang, Hai-Tao

2014-11-01

174

Metal element adsorbent manufacturing method and separation method of metal element by the adsorbent  

International Nuclear Information System (INIS)

Condensated type tannin acid powders are dissolved in an aqueous ammonia solution, to which an aqueous solution of aldehyde is mixed, to form a gel-like composition and it is stabilized by aging at a room temperature or by heating, to obtain an excellent adsorbent for metal elements. According to this method, since a great amount of tannin which is extracted from natural materials except for persimmon tannin, resources can be utilized effectively. If the adsorbent is fractionated to a predetermined size and filled in a column, a performance of processing solutions can be remarkably improved. (T.M.)

175

Selective radium adsorbent  

International Nuclear Information System (INIS)

The selective radium adsorbent is a ternary compound insoluble in water consisting of cations forming water-soluble complexes with polyalkylene glycols and the derivatives thereof, e.g., the cations of barium, calcium, strontium, magnesium, zinc, and potassium; of polyalkylene glycol or its derivative soluble in water with 2 to 4 carbon atoms in the basic unit of molecular weight at least 20O; and of a reagent forming large anions, chosen from a group comprising heteropolyacids of the tungstophosphoric, molybdophosphoric and tungstosilicic acids type, sodium tetraphenylborate and bismuth iodides. This reagent is also water-soluble. (B.S.)

176

Substrate-adsorbate coupling in CO-adsorbed copper  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The vibrational properties of carbon monoxide adsorbed to the copper (100) surface are explored within density functional theory. Atoms of the substrate and adsorbate are treated on an equal footing in order to examine the effect of substrate--adsorbate coupling. This coupling is found to have a significant effect on the vibrational modes, particularly the in-plane frustrated translation, which mixes strongly with substrate phonons and broadens into a resonance. The predicte...

Lewis, Steven P.; Rappe, Andrew M.

1996-01-01

177

Self-assembly of graphene oxide coated soft magnetic carbonyl iron particles and their magnetorheology  

Energy Technology Data Exchange (ETDEWEB)

The surface of carbonyl iron (CI) microspheres was modified with graphene oxide (GO) as a coating material using 4-aminobenzoic acid as the grafting agent. The morphology, elemental composition, and magnetic properties of the GO-coated CI (GO/CI) particles were examined by scanning electron microscopy, energy dispersive X-ray spectroscopy and vibrating sample magnetometry, respectively, confirming their composite formation. The magnetorheological (MR) performance of the GO/CI particle-based suspension was examined using a rotational rheometer connected to a magnetic field supply. The GO/CI particles suspension exhibited typical MR properties with increasing shear stress and viscosity depending on the applied magnetic field strength.

Zhang, W. L.; Choi, H. J., E-mail: hjchoi@inha.ac.kr [Department of Polymer Science and Engineering, Inha University, Incheon 402-751 (Korea, Republic of)

2014-05-07

178

Self-assembly of graphene oxide coated soft magnetic carbonyl iron particles and their magnetorheology  

International Nuclear Information System (INIS)

The surface of carbonyl iron (CI) microspheres was modified with graphene oxide (GO) as a coating material using 4-aminobenzoic acid as the grafting agent. The morphology, elemental composition, and magnetic properties of the GO-coated CI (GO/CI) particles were examined by scanning electron microscopy, energy dispersive X-ray spectroscopy and vibrating sample magnetometry, respectively, confirming their composite formation. The magnetorheological (MR) performance of the GO/CI particle-based suspension was examined using a rotational rheometer connected to a magnetic field supply. The GO/CI particles suspension exhibited typical MR properties with increasing shear stress and viscosity depending on the applied magnetic field strength

179

Thermal behavior of Ni- and Cu-containing plasma electrolytic oxide coatings on titanium  

Science.gov (United States)

In this work the effect of thermal annealing on the surface composition, structure and catalytic activity in CO oxidation of NiO + CuO/TiO2/Ti composites is studied. The composites have been obtained by a plasma electrolytic oxidation (PEO) technique, followed by impregnation in a solution of nickel (II) and copper (II) salts and air annealing. The structures contain ˜20 at% Ni and ˜12 at% Cu. It has been shown that the additional air annealing of such structures at temperature above 750 °C results in phosphate crystallization in the coatings and decreasing of Cu concentration in the surface layers. A growth of filiform nanocrystals containing mainly oxygen compounds of nickel and titanium on the coating surface takes place at the temperatures above 700 °C. The nanocrystals have a diameter of 50-200 nm and lengths below 10 ?m. Such changes result in decreasing of catalytic activity of the composites in CO oxidation. At the same time the ascertained regularities may be of interest for obtaining the Ni-containing oxide catalysts with an extended surface, perspective for usage in organic catalysis or for preparing oxide nanofibers.

Rudnev, V. S.; Wybornov, S.; Lukiyanchuk, I. V.; Staedler, T.; Jiang, X.; Ustinov, A. Yu.; Vasilyeva, M. S.

2012-09-01

180

High performance Mo adsorbent PZC  

Energy Technology Data Exchange (ETDEWEB)

We have developed Mo adsorbents for natural Mo(n, {gamma}){sup 99}Mo-{sup 99m}Tc generator. Among them, we called the highest performance adsorbent PZC that could adsorb about 250 mg-Mo/g. In this report, we will show the structure, adsorption mechanism of Mo, and the other useful properties of PZC when you carry out the examination of Mo adsorption and elution of {sup 99m}Tc. (author)

Anon.

1998-10-01

 
 
 
 
181

Positronium chemistry in porous adsorbents  

International Nuclear Information System (INIS)

Kinetic studies on the annihilation of orthopositronium in porous adsorbents have been performed using lifetime spectroscopy. The positron source applied was 22Na with 0.2 MBq activity. The adsorbents investigated were silica gels of different particle size and pore structure. The appearance of the long-lived component in the lifetime spectra can be explained by the diffusion of the orthopositronium into the pores affected by the particle size and the pore size of the adsorbent, the coverage on it and the chemical nature of the adsorbate. The long-term aim of the work is to determine and to explain these effects. (author)

182

Green Adsorbents for Wastewaters: A Critical Review  

Directory of Open Access Journals (Sweden)

Full Text Available One of the most serious environmental problems is the existence of hazardous and toxic pollutants in industrial wastewaters. The major hindrance is the simultaneous existence of many/different types of pollutants as (i dyes; (ii heavy metals; (iii phenols; (iv pesticides and (v pharmaceuticals. Adsorption is considered to be one of the most promising techniques for wastewater treatment over the last decades. The economic crisis of the 2000s led researchers to turn their interest in adsorbent materials with lower cost. In this review article, a new term will be introduced, which is called “green adsorption”. Under this term, it is meant the low-cost materials originated from: (i agricultural sources and by-products (fruits, vegetables, foods; (ii agricultural residues and wastes; (iii low-cost sources from which most complex adsorbents will be produced (i.e., activated carbons after pyrolysis of agricultural sources. These “green adsorbents” are expected to be inferior (regarding their adsorption capacity to the super-adsorbents of previous literature (complex materials as modified chitosans, activated carbons, structurally-complex inorganic composite materials etc., but their cost-potential makes them competitive. This review is a critical approach to green adsorption, discussing many different (maybe in some occasions doubtful topics such as: (i adsorption capacity; (ii kinetic modeling (given the ultimate target to scale up the batch experimental data to fixed-bed column calculations for designing/optimizing commercial processes and (iii critical techno-economical data of green adsorption processes in order to scale-up experiments (from lab to industry with economic analysis and perspectives of the use of green adsorbents.

George Z. Kyzas

2014-01-01

183

Creation of thin oxide coatings and oxide nanopowders by anodic oxidation of metals in molten salts  

International Nuclear Information System (INIS)

One studied possibility to synthesize highly dispersed oxide powders at anodic oxidation of metals like zirconium and tantalum in chloride nitrate melt (CsCl+NaCl+NaNO3) under temperatures higher than 830 K. It is shown that it is possible to prepare either dense oxide protective coatings on the mentioned metals or oxide powders the particle size of which ranges from 50 up to 100 nm when changing electrolyte composition, oxidation temperature and anode current density

184

Arsenic remediation of drinking water using iron-oxide coated coal bottom ash  

Energy Technology Data Exchange (ETDEWEB)

We describe laboratory and field results of a novel arsenic removal adsorbent called 'Arsenic Removal Using Bottom Ash' (ARUBA). ARUBA is prepared by coating particles of coal bottom ash, a waste material from coal fired power plants, with iron (hydr)oxide. The coating process is simple and conducted at room temperature and atmospheric pressure. Material costs for ARUBA are estimated to be low (~;;$0.08 per kg) and arsenic remediation with ARUBA has the potential to be affordable to resource-constrained communities. ARUBA is used for removing arsenic via a dispersal-and-removal process, and we envision that ARUBA would be used in community-scale water treatment centers. We show that ARUBA is able to reduce arsenic concentrations in contaminated Bangladesh groundwater to below the Bangladesh standard of 50 ppb. Using the Langmuir isotherm (R2 = 0.77) ARUBA's adsorption capacity in treating real groundwater is 2.6x10-6 mol/g (0.20 mg/g). Time-to-90percent (defined as the time interval for ARUBA to remove 90percent of the total amount of arsenic that is removed at equilibrium) is less than one hour. Reaction rates (pseudo-second-order kinetic model, R2>_ 0.99) increase from 2.4x105 to 7.2x105 g mol-1 min-1 as the groundwater arsenic concentration decreases from 560 to 170 ppb. We show that ARUBA's arsenic adsorption density (AAD), defined as the milligrams of arsenic removed at equilibrium per gram of ARUBA added, is linearly dependent on the initial arsenic concentration of the groundwater sample, for initial arsenic concentrations of up to 1600 ppb and an ARUBA dose of 4.0 g/L. This makes it easy to determine the amount of ARUBA required to treat a groundwater source when its arsenic concentration is known and less than 1600 ppb. Storing contaminated groundwater for two to three days before treatment is seen to significantly increase ARUBA's AAD. ARUBA can be separated from treated water by coagulation and clarification, which is expected to be less expensive than filtration of micron-scale particles, further contributing to the affordability of a community-scale water treatment center.

MATHIEU, JOHANNA L.; GADGIL, ASHOK J.; ADDY, SUSAN E.A.; KOWOLIK, KRISTIN

2010-06-01

185

Surface-initiated growth of thin oxide coatings for Li-sulfur battery cathodes  

Energy Technology Data Exchange (ETDEWEB)

The concept of surface-initiated growth of oxides on functionalized carbons is introduced as a method to inhibit the dissolution of polysulfide ions in Li-S battery cathode materials. MO{sub x} (M: Si, V) thin layers are homogeneously coated on nanostructured carbon-sulfur composites. The coating significantly inhibits the dissolution of polysulfides on cycling, resulting in enhanced cycle performance and coulombic efficiency of the Li-S battery. (Copyright copyright 2012 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

Lee, Kyu Tae; Black, Robert; Yim, Taeeun; Ji, Xiulei; Nazar, Linda F. [University of Waterloo, Department of Chemistry, Waterloo, ON (Canada)

2012-12-15

186

Dry Sliding Behavior of Sub-Micrometer-Sized Suspension Plasma Sprayed Ceramic Oxide Coatings  

Science.gov (United States)

Almost half of the energy produced by an automotive engine is dissipated by friction in the cylinders, the clutch, etc. In the context of reduction of the emissions of greenhouse gases (GHGs) to mitigate climate global warming (CGW), reduction of energy losses due to friction is a critical issue. Surface treatments appear in such a context, as never than before, to be able to provide pertinent solutions to improve sliding behavior of mechanical parts. Numerous studies have clearly shown that decreasing the scale of coating structure below the micrometer scale was leading to an improvement of its tribological behavior in terms of friction coefficient and wear rate thanks to improved mechanical properties, the toughness in particular. Suspension Plasma Spraying (SPS) appears as a thermal spray process to be able to manufacture thick (i.e., a few tens of micrometers) coatings exhibiting a sub-micrometer-sized or even a nanometer-sized architecture, while keeping the versatility and flexibility of the thermal spray routes: i.e., the ability to process a wide range of material natures onto a wide range of substrate materials of various geometries. This article aims at studying the tribological behavior of several ceramic oxide composite coatings under dry conditions. The structural scale and the effect of composition are considered in particular.

Darut, Geoffrey; Ben-Ettouil, Fadhel; Denoirjean, Alain; Montavon, Ghislain; Ageorges, Hélène; Fauchais, Pierre

2010-01-01

187

Development of molecular adsorber coatings  

Science.gov (United States)

As mission, satellite, and instrument performance requirements become more advanced, the need to control adverse onorbit molecular contamination is more critical. Outgassed materials within the spacecraft have the potential to degrade performance of optical surfaces, thermal control surfaces, solar arrays, electronics, and detectors. One method for addressing the outgassing of materials is the use of molecular adsorbers. On Goddard Space Flight Center missions such as Hubble Space Telescope (HST), Tropical Rainfall Measuring Mission (TRMM), and SWIFT, Zeolite-coated cordierite molecular adsorbers were successfully used to collect and retain outgassed molecular effluent emanating from spacecraft materials, protecting critical contamination sensitive surfaces. However, the major drawbacks of these puck type adsorbers are weight, size, and mounting hardware requirements, making them difficult to incorporate into spacecraft designs. To address these concerns, a novel molecular adsorber coating was developed to alleviate the size and weight issues while providing a configuration that more projects can utilize, particularly contamination sensitive instruments. This successful sprayable molecular adsorber coating system demonstrated five times the adsorption capacity of previously developed adsorber coating slurries. The molecular adsorber formulation was refined and a procedure for spray application was developed. Samples were spray coated and tested for capacity, thermal optical/radiative properties, coating adhesion, and thermal cycling. The tested formulation passes coating adhesion and vacuum thermal cycling tests between +140 and -115C. Thermal radiative properties are very promising. Work performed during this study indicates that the molecular adsorber formulation can be applied to aluminum, stainless steel, or other metal substrates that can accept silicate coatings.

Straka, Sharon; Peters, Wanda; Hasegawa, Mark; Novo-Gradac, Kevin; Wong, Alfred

2010-08-01

188

Heterogeneous oligonucleotide-hybridization assay based on hot electron-induced electrochemiluminescence of a rhodamine label at oxide-coated aluminum and silicon electrodes  

International Nuclear Information System (INIS)

This paper describes a heterogeneous oligonucleotide-hybridization assay based on hot electron-induced electrochemiluminescence (HECL) of a rhodamine label. Thin oxide-film coated aluminum and silicon electrodes were modified with an aminosilane layer and derivatized with short, 15-mer oligonucleotides via diisothiocyanate coupling. Target oligonucleotides were conjugated with tetramethylrhodamine (TAMRA) dye at their amino modified 5' end and hybridization was detected using HECL of TAMRA. Preliminary results indicate sensitivity down to picomolar level and low nonspecific adsorption. The sensitivity was better on oxide-coated silicon compared to oxide-coated aluminum electrodes and two-base pair mismatched hybrids were successfully discriminated. The experimental results presented here might be useful for the design of disposable electrochemiluminescent DNA biosensors

189

Spectral and optical performance of electrochromic poly(3,4-ethylenedioxythiophene) (PEDOT) deposited on transparent conducting oxide coated glass and polymer substrates  

Energy Technology Data Exchange (ETDEWEB)

Electrochromic devices utilizing conjugated polymers as electrochromic layers have gained increasing attention owing to their optical properties, fast switching times and contrast ratios. Polyethylenedioxythiophene (PEDOT) is an excellent material from its electrochromic properties, high conductivity and high stability in the doped form. Aqueous dispersions of PEDOT were either spin coated or electro-polymerized on transparent conducting oxide coated glass and polyethylene tetraphthalate (PET) film substrates. The spectro- and opto-electrochemical studies of the films on transparent conducting oxide coated glass/PET substrates were performed. These films have application in the fabrication of electrochromic windows (smart windows). Smart window devices having excellent switching characteristics over wide range of temperature are used for glazing applications. The aerospace industry is interested in the development of visors and windows that can control glare for pilots and passengers, especially if the coatings can be made on curved surfaces and electrically conducting.

Sindhu, S. [Dept. of Instrumentation, Indian Institute of Science, Bangalore 560012 (India)]. E-mail: sindhu@isu.iisc.ernet.in; Narasimha Rao, K. [Dept. of Instrumentation, Indian Institute of Science, Bangalore 560012 (India); Ahuja, Sharath [Dept. of Instrumentation, Indian Institute of Science, Bangalore 560012 (India); Kumar, Anil [Dept. of Chemistry, Indian Institute of Technology, Bombay 400 076 (India); Gopal, E.S.R. [Dept. of Physics, Indian Institute of Science, Bangalore 560012 (India)

2006-07-25

190

Spectral and optical performance of electrochromic poly(3,4-ethylenedioxythiophene) (PEDOT) deposited on transparent conducting oxide coated glass and polymer substrates  

International Nuclear Information System (INIS)

Electrochromic devices utilizing conjugated polymers as electrochromic layers have gained increasing attention owing to their optical properties, fast switching times and contrast ratios. Polyethylenedioxythiophene (PEDOT) is an excellent material from its electrochromic properties, high conductivity and high stability in the doped form. Aqueous dispersions of PEDOT were either spin coated or electro-polymerized on transparent conducting oxide coated glass and polyethylene tetraphthalate (PET) film substrates. The spectro- and opto-electrochemical studies of the films on transparent conducting oxide coated glass/PET substrates were performed. These films have application in the fabrication of electrochromic windows (smart windows). Smart window devices having excellent switching characteristics over wide range of temperature are used for glazing applications. The aerospace industry is interested in the development of visors and windows that can control glare for pilots and passengers, especially if the coatings can be made on curved surfaces and electrically conducting

191

Adhesive and corrosion-resistant zirconium oxide coatings on stainless steel prepared by ion beam assisted deposition  

Science.gov (United States)

To improve the adhesion and corrosion resistance in ceramic and steel systems, zirconium oxide films were deposited on austenitic type 316L stainless-steel substrates by using the ion beam assisted deposition (IBAD) method, in which ZrO 2 evaporation and energetic Ar and/or O 2 ion bombardment at 250 eV were carried out simultaneously. To study the influence of the film thickness on the performance of coatings, thin (0.2-0.4 ?m) and thick (2-3 ?m) films were prepared. The film structure was investigated by X-ray diffractometry. The adhesion was evaluated by a tensile pull-off tester, showing that IBAD treatments could provide a remarkable potential to enhance the adhesion. The corrosion behavior was determined by potentio-dynamic polarization measurements. It was found that excellent corrosion-protection ability of zirconium oxide coatings on stainless steel was achieved after IBAD treatments. The mechanism for explaining the results has been discussed in terms of the surface observation and X-ray photoelectron spectroscopy studies.

Hasuyama, Hiroki; Shima, Yukari; Baba, Koumei; Wolf, Gerhard K.; Martin, Herbert; Stippich, Frank

1997-05-01

192

Adhesive and corrosion-resistant zirconium oxide coatings on stainless steel prepared by ion beam assisted deposition  

International Nuclear Information System (INIS)

To improve the adhesion and corrosion resistance in ceramic and steel systems, zirconium oxide films were deposited on austenitic type 316L stainless-steel substrates by using the ion beam assisted deposition (IBAD) method, in which ZrO2 evaporation and energetic Ar and/or O2 ion bombardment at 250 eV were carried out simultaneously. To study the influence of the film thickness on the performance of coatings, thin (0.2-0.4 ?m) and thick (2-3 ?m) films were prepared. The film structure was investigated by X-ray diffractometry. The adhesion was evaluated by a tensile pull-off tester, showing that IBAD treatments could provide a remarkable potential to enhance the adhesion. The corrosion behavior was determined by potentio-dynamic polarization measurements. It was found that excellent corrosion-protection ability of zirconium oxide coatings on stainless steel was achieved after IBAD treatments. The mechanism for explaining the results has been discussed in terms of the surface observation and X-ray photoelectron spectroscopy studies. (orig.)

193

Removal of iron and arsenic (III) from drinking water using iron oxide-coated sand and limestone  

Science.gov (United States)

A method for removal of iron and arsenic (III) from contaminated water using iron oxide-coated sand and limestone has been developed for drinking water. For the intended use, sand was coated with ferric chloride and used as filtering media. Limestone was added onto the coated sand and the effect of limestone addition on removal efficiency of iron and arsenic was monitored. Both batch and column experiments were conducted to investigate the efficiency of coated sand and limestone as filtering media. Maximum removal of iron (99.8 %) was obtained with coated sand at a dose of 5 g/100 ml and by adding 0.2 g/100 ml of limestone at pH 7.3. Arsenic (III) removal efficiency increased with the increased dose of coated sand and was best removed at pH 7.12. The maximum adsorption capacity for arsenic (III) obtained from Langmuir model was found to be 0.075 mg/g and the kinetics data followed pseudo-first order better than pseudo-second order. Energy dispersive X-ray analysis and FT-IR study proved the removal of iron and arsenic. Column experiment showed removal of iron and arsenic (III) to arsenic).

Devi, Rashmi R.; Umlong, Iohborlang M.; Das, Bodhaditya; Borah, Kusum; Thakur, Ashim J.; Raul, Prasanta K.; Banerjee, Saumen; Singh, Lokendra

2014-06-01

194

Enhanced mechanical and electrical properties of antimony-doped tin oxide coatings  

International Nuclear Information System (INIS)

Multi-walled carbon nanotubes (MWNTs) dispersed in surfactants were investigated as additional conductive elements in an antimony-doped tin oxide (ATO) matrix. Dispersion of MWNTs in a cationic surfactant was more efficient than in anionic or non-ionic surfactants. Precursor solutions as well as coatings of ATO and ATO/MWNT composites were characterized. The effect of the addition of MWNTs on the optical, electrical and mechanical properties of the original ATO coatings was demonstrated. Low concentrations of MWNTs are sufficient to decrease the resistivity of conducting ATO films by a factor of 16, with preserved transparency (90%) in the visible range. Fewer ATO nanoparticles and lower sintering temperatures than those presented in the literature lead to films with comparable resistivities and even higher transparency, with reduced manufacturing costs. The addition of MWNTs has also increased the hardness of the ATO coatings from HB to 2H–4H, depending on the MWNT concentration employed

195

Adsorbed Water Illustration  

Science.gov (United States)

The Thermal and Electrical Conductivity Probe on NASA's Phoenix Mars Lander detected small and variable amounts of water in the Martian soil. In this schematic illustration, water molecules are represented in red and white; soil minerals are represented in green and blue. The water, neither liquid, vapor, nor solid, adheres in very thin films of molecules to the surfaces of soil minerals. The left half illustrates an interpretation of less water being adsorbed onto the soil-particle surface during a period when the tilt, or obliquity, of Mars' rotation axis is small, as it is in the present. The right half illustrates a thicker film of water during a time when the obliquity is greater, as it is during cycles on time scales of hundreds of thousands of years. As the humidity of the atmosphere increases, more water accumulates on mineral surfaces. Thicker films behave increasingly like liquid water. The Phoenix Mission is led by the University of Arizona, Tucson, on behalf of NASA. Project management of the mission is by NASA's Jet Propulsion Laboratory, Pasadena, Calif. Spacecraft development is by Lockheed Martin Space Systems, Denver.

2008-01-01

196

Microstructure and biological properties of micro-arc oxidation coatings on ZK60 magnesium alloy.  

Science.gov (United States)

Ceramic coatings were prepared on ZK60 magnesium alloy in electrolyte with different concentration ratio of calcium and phosphorus (Ca/P) by micro-arc oxidation (MAO) technique at constant voltage. The microstructure, phase composition, elemental distribution, corrosion resistance, and adhesion of the coatings were investigated by scanning electron microscope (SEM), X-ray diffractometer (XRD), energy-dispersive X-ray spectrometry (EDS), electrochemical workstation, and scratch spectrometer, respectively. The coating biocompatibility was evaluated by in vitro cytotoxicity tests and systemic toxicity tests, and the bioactivity and degradability were evaluated by simulation body fluid (SBF) immersion tests. SEM shows that pores with different shapes distribute all over the coating surface. The adhesion and thickness of the coatings increases with increasing Ca/P ratio of electrolyte. The in vitro cytotoxicity tests and systemic toxicity texts demonstrate that the coatings have no toxicity to cell and living animal, which show that the coatings have excellent biocompatibility. XRD analysis shows that bioactive calciumphosphate (CaP) phases such as hydroxyapatite (HA, Ca(10)(PO(4))(6)(OH)(2)) and calcium pyrophosphate (CPP, Ca(2)P(2)O(7)) are induced in the immersed coatings, indicating that the MAO coatings have excellent bioactivity. PMID:22692915

Pan, Y K; Chen, C Z; Wang, D G; Yu, X

2012-08-01

197

Stress-corrosion cracking of indium tin oxide coated polyethylene terephthalate for flexible optoelectronic devices  

International Nuclear Information System (INIS)

Stress corrosion cracking of transparent conductive layers of indium tin oxide (ITO), sputtered on polyethylene terephthalate (PET) substrates, is an issue of paramount importance in flexible optoelectronic devices. These components, when used in flexible device stacks, can be in contact with acid containing pressure-sensitive adhesives or with conductive polymers doped in acids. Acids can corrode the brittle ITO layer, stress can cause cracking and delamination, and stress-corrosion cracking can cause more rapid failure than corrosion alone. The combined effect of an externally-applied mechanical stress to bend the device and the corrosive environment provided by the acid is investigated in this work. We show that acrylic acid which is contained in many pressure-sensitive adhesives can cause corrosion of ITO coatings on PET. We also investigate and report on the combined effect of external mechanical stress and corrosion on ITO-coated PET composite films. Also, it is shown that the combination of stress and corrosion by acrylic acid can cause ITO cracking to occur at stresses less than a quarter of those needed for failure with no corrosion. In addition, the time to failure, under ? 1% tensile strain can reduce the total time to failure by as much as a third

198

Nano-SiC/SiC anti-oxidant coating on the surface of graphite  

Science.gov (United States)

In this research, a dual-layer coating has been used to improve high temperature oxidation resistance of graphite substrate. For first layer, silicon carbide was applied by pack cementation method. Powder pack consisted of Si, SiC and Al2O3 and heat-treated at 1650 °C in an argon atmosphere. SEM and XRD characterizations confirmed formation of SiC diffusion coating with about 500 ?m including compositionally gradient of C and Si elements. Electrophoretic deposition (EPD) was used to deposit nano SiC (SiCn) particles as second layer. Thickness of second layer of SiCn in corresponded optimal situation was 50 ?m. Samples with single and dual layers were investigated in oxidation test at 1600 °C. Results showed that an extreme increase was occurred in oxidation resistance after application of second layer of nano SiC. Weight loss value for single layer coating of SiC and dual layer coating of SiCn/SiC after oxidation test for 28 h at 1600 °C were 29 wt.% and 2.4 wt.%, respectively.

Jafari, H.; Ehsani, N.; Khalifeh-Soltani, S. A.; Jalaly, M.

2013-01-01

199

Lubricating Properties of Some Bonded Fluoride and Oxide Coatings for Temperature to 1500 F  

Science.gov (United States)

The lubricating properties of some experimental ceramic coatings, diffusion-bonded fluoride coatings, and ceramic-bonded fluoride coatings were determined. The experiments were conducted in an air atmosphere at a sliding velocity of 430 feet per minute and at temperatures from 75 to 1500 F. Several ceramic coatings provided substantial reductions in friction coefficient and rider wear (compared with the unlubricated metals). For example, a cobaltous oxide (CoO) base coating gave friction coefficients of 0.24 to 0.36 within the temperature range of 75 to 1400 F; serious galling and welding of the metal surfaces were prevented. The friction coefficients were higher than the arbitrary maximum (0.2) usually considered for effective boundary lubrication. However, when a moderately high friction coefficient can be tolerated, this type of coating may be a useful antiwear composition. Diffusion-bonded calcium fluoride (CaF2) on Haynes Stellite 21 and on Inconel X gave friction coefficients of 0.1 to 0.2 at 1500 F. Endurance life was dependent on the thermal history of the coating; life improved with increased exposure time at elevated temperatures prior to running. Promising results were obtained with ceramic-bonded CaF2 on Inconel X. Effective lubrication and good adherence were obtained with a 3 to 1 ratio of CaF2 to ceramic. A very thin sintered and burnished film of CaF2 applied to the surface of this coating further improved lubrication, particularly above 1350 F. The friction coefficient was 0.2 at 500 F and decreased with increasing temperature to 0.06-at 1500 F. It was 0.25 at 75 F and 0.22 at 250 F.

Sliney, Harold E.

1960-01-01

200

The phase and microstructural analysis of protective oxide coatings on molybdenum  

International Nuclear Information System (INIS)

Due to their high sensitivity to oxygen, the use of refractory metals requires an effective protection against oxidation. In the case of molybdenum this is achieved by using a silicon and boron based coating commercially marketed under the trade name SIBOR registered. In the moduction of a SIBOR registered -coating, a mixture of Si, B and C is plasma sprayed in air onto the Mo-surface to be protected and subsequently annealed in hydrogen. Previous investigations have shown that in doing so a stationary coating of Mo-borides and Mo-silicides is formed. However, the exact phase arrangement and composition has until now remained unclear. Energy dispersive X-ray spectroscopy (EDS) in the scanning electron microscope (SEM) is able to analyse the silicides in SIBOR registered, although due to the overlapping of the Mo-and B-spectral partial a clear identification of the borides was not possible. Using a combination of electron back scatter diffraction (EBSD) and wavelength dispersive X-ray spectroscopy (WDS) it is, however, shown that SIBOR registered is made up of a series of sublayers of Mo2B and MoB followed by Mo5Si3 and MoSi2, and that the other phases of the Mo-Si-B ternary system, i.e. Mo3Si and Mo5SiB2(T2), do not occur. Notably, the two borides and the Mo5Si3 exhibit a structure which is polycrystalline in the lateral direction yet normal to the surface forms of only a single layer of crystallites. In contrast, the final MoSi2-layer has a polycrystalline structure both in the lateral and in the normal directions. Furthermore, Mo5Si3 and MoSi2 both exhibit marked textures. (orig.)

 
 
 
 
201

Neutron scattering from adsorbed systems  

International Nuclear Information System (INIS)

The subject is reviewed under the headings: introduction; the technique and theory of neutron scattering; neutron diffraction from physisorbed layers; inelastic scattering from adsorbed molecules; quasielastic scattering from heterogeneous systems. (U.K.)

202

Preparation of metal adsorbents from chitin/chitosan by radiation technology  

International Nuclear Information System (INIS)

The methods of preparation of metal adsorbents basing on chitin/chitosan were developed. That include the adsorbent from chitin grafted with acrylic acid by different irradiation doses; the clinging chitosan gel beads; the coagulable solution and the chitosan composite filter. The process of metal adsorption for each adsorbent was studied as adsorption kinetic, isothermal adsorption. The results have been applied for removal of some elements as Hg, Pb, Cd, U, Cu, ect. in the wastewater. (NHA)

203

Validation of In-Situ Iron-Manganese Oxide Coated Stream Pebbles as Sensors for Arsenic Source Monitoring  

Science.gov (United States)

Locating nonpoint source contaminant fluxes can be challenging due to the inherent heterogeneity of source and of the subsurface. Contaminants such as arsenic are a concern for drinking water quality and ecosystem health. Arsenic contamination can be the result of several natural and anthropogenic sources, and therefore it can be difficult to trace and identify major areas of arsenic in natural systems. Identifying a useful source indicator for arsenic is a crucial step for environmental remediation efforts. Previous studies have found iron-manganese oxide coated streambed pebbles as useful source indicators due to their high attraction for heavy metals in water. In this study, pebbles, surface water at baseflow and nearby rocks were sampled from the Pennypack Creek and its tributaries, in southwestern Pennsylvania, to test the ability of coated streambed pebbles as environmental source indicators for arsenic. Quartz pebbles, 5-7 cm in diameter, were sampled to minimize elemental contamination from rock chemistry. In addition, quartz provides an excellent substrate for iron and manganese coatings to form. These coatings were leached from pebbles using 4M nitric acid with 0.1% concentrated hydrochloric acid. Following sample processing, analyses were performed using an ICP-MS and the resulting data were spatially organized using ArcGIS software. Arsenic, iron and manganese concentrations in the leachate are normalized to pebble surface area and each location is reported as a ratio of arsenic to iron and manganese. Results suggest that iron-manganese coated stream pebbles are useful indicators of arsenic location within a watershed.

Blake, J.; Peters, S. C.; Casteel, A.

2013-12-01

204

Instability of waste plumes adsorbed on iron oxide in soils  

International Nuclear Information System (INIS)

Iron (hydrous) oxide coatings on the solid matrix dominate adsorption in many soils. Their adsorption characteristics vary considerably with the composition of the soil pore water. If the latter is not sufficiently buffered, the contaminant distribution between solid and soluble soil phase, Kd (''distribution coefficient''), will change as intruding water differing in chemical composition from the original one in the system progresses through the plume environment. Thus the Kd's at different locations within the plume become time dependent, spatially variable and causally correlated. The conventional constant or stochastic Kd model is not capable of describing contaminant migration in such a situation. A geochemical equilibrium model, the so-called triple layer model, has been incorporated into a transport code and is used to calculate the adsorption processes and thus the Kd as a function of environmental parameters. The major processes occurring are: (1) accumulation of a proton reservoir on the surface itself; (2) development of a charge cloud at a distance of several angstroms from the surface, capable of accommodating contaminant ions; and (3) development of a net charge at the oxide/water interface and, consequently, the creation of a cation or anion exchange capacity of the oxide

205

Influence of C 3H 8O 3 in the electrolyte on characteristics and corrosion resistance of the microarc oxidation coatings formed on AZ91D magnesium alloy surface  

Science.gov (United States)

Ceramic coatings were fabricated on AZ91D Mg-alloy substrate by microarc oxidation in Na 2SiO 3-NaOH-Na 2EDTA electrolytes with and without C 3H 8O 3 addition. The effects of different concentrations of C 3H 8O 3 contained in the electrolyte on coatings thickness were investigated. The surface morphologies, RMS roughness, phase compositions and corrosion resistance property of the ceramic coatings were analyzed by scanning electron microscopy (SEM), atomic force microscopy (AFM), X-ray diffraction (XRD), and electrochemical corrosion test respectively. It is found that the addition of C 3H 8O 3 into silicate electrolyte leads to increase of the unit-area adsorptive capacity of the negative ions at anode-electrolyte interface and thus improves the compactness and corrosion resistance of the MAO coating. The coating thickness decreases gradually with the increase of concentrations of C 3H 8O 3 in the electrolyte. The oxide coating formed in base electrolyte containing 4 mL/L C 3H 8O 3 exhibits the best surface appearance, the lowest surface RMS roughness (174 nm) and highest corrosion resistance. In addition, both ceramic coatings treated in base electrolyte with and without C 3H 8O 3 are mainly composed of periclase MgO and forsterite Mg 2SiO 4 phase, but no diffraction peak of Mg phase is found in the patterns.

Wu, Di; Liu, Xiangdong; Lu, Kai; Zhang, Yaping; Wang, Huan

2009-05-01

206

Rotary adsorbers for continuous bulk separations  

Science.gov (United States)

A rotary adsorber for continuous bulk separations is disclosed. The rotary adsorber includes an adsorption zone in fluid communication with an influent adsorption fluid stream, and a desorption zone in fluid communication with a desorption fluid stream. The fluid streams may be gas streams or liquid streams. The rotary adsorber includes one or more adsorption blocks including adsorbent structure(s). The adsorbent structure adsorbs the target species that is to be separated from the influent fluid stream. The apparatus includes a rotary wheel for moving each adsorption block through the adsorption zone and the desorption zone. A desorption circuit passes an electrical current through the adsorbent structure in the desorption zone to desorb the species from the adsorbent structure. The adsorbent structure may include porous activated carbon fibers aligned with their longitudinal axis essentially parallel to the flow direction of the desorption fluid stream. The adsorbent structure may be an inherently electrically-conductive honeycomb structure.

Baker, Frederick S. (Oak Ridge, TN)

2011-11-08

207

The effects of argon pre-annealing on the superconductive properties of plasma-sprayed Y-Ba-Cu-oxide coatings  

International Nuclear Information System (INIS)

Plasma spraying is a deposition method with the potential of producing large quantities of high temperature superconductive coatings. The as-sprayed Y-Ba-Cu-oxide coatings are mostly the substitution tetragonal phase, YBa2-xYxCu3Oy. Oxygen-annealing of this phase below 960 degree C results in a poorly-superconducting orthorhombic phase. However, this study shows that the superconducting properties can be improved by annealing the as-sprayed coatings in an argon atmosphere at 850 degree C prior to the oxygen annealing

208

Diatomaceous earth containing adsorbent, method for making, and methods of use thereof  

International Nuclear Information System (INIS)

An absorbent composition containing sugar, vinegar, and diatomaceous earth is disclosed. The sugar, vinegar, and diatomaceous earth are preferably added together in about equal amounts by volume or in amounts of about 20 pounds of sugar, 2 gallons of vinegar, and 100 pounds of diatomaceous earth. The adsorbent composition has particular use in adsorbing petroleum from soil, water, or air and in water purification. (author)

209

Adsorbent Removes Traces Of Oxygen  

Science.gov (United States)

An adsorbent, carbon molecular sieve containing copper oxide, selectively removes oxygen from gas mixtures, producing gas containing less than 1 part per billion of oxygen. Used to help prevent oxidation of chemicals being prepared in dry boxes or to extract undesired traces of oxygen from inert-gas chambers in which flammable gases are stored.

Sharma, Pramod K.; Seshan, Panchalam K.

1991-01-01

210

Graphene oxide coated capillary for the analysis of endocrine-disrupting chemicals by open-tubular capillary electrochromatography with amperometric detection.  

Science.gov (United States)

A graphene oxide-coated capillary was fabricated by using 3-aminopropyltriethoxysilane as the cross-linking agent. It was used for the separation and detection of three endocrine-disrupting chemicals, including bisphenol A, 4-nonylphenol, and 4-octylphenol by capillary electrochromatography. Due to the hydrophobicity, hydrogen bonding, and ?-? interaction between graphene oxide and the analytes, the three analytes could be well separated in pH = 11.0, 20 mmol/L Na2 B4 O7 -NaOH/methanol mobile phase (50:50, v/v) within 950 s. After preconcentration, the detection limits were 6.7 × 10(-10) , 3.3 × 10(-9) , and 6.7 × 10(-10)  mol/L (S/N = 3) for bisphenol A, nonylphenol, and octylphenol, respectively. The developed method was successfully applied to the determination of the above analytes in water samples. The satisfactory result demonstrated that the graphene oxide coated capillary used in capillary electrochromatography with amperometric detection was convenient to prepare, highly stable, and had good reproducibility. PMID:24729294

Jiang, Xiaoying; Jiang, Yuehuang; Shi, Guoyue; Zhou, Tianshu

2014-07-01

211

Water vapor adsorption characteristics of honeycomb adsorbents  

International Nuclear Information System (INIS)

For large volume air clean-up in nuclear fusion facilities, honeycomb-type adsorbents offer a useful advantage in terms of their low-pressure drop. In this study, two different honeycomb-type adsorbents (honeycomb-K and honeycomb-N) and pebble-type adsorbents were used as samples and the water vapor adsorption performance of each adsorbent was examined by changing temperature, concentration of water vapor and flow rate. The honeycomb-K and honeycomb-N adsorbents included zeolite-4A or zeolite-5A with a 50% clay binder and with a 15% sepiolite binder, respectively. The shapes of cells in honeycomb-K and honeycomb-N are triangles with 1 mm sides and squares with 1 mm sides, respectively, and the cell densities of the both adsorbents were 200 CPSI (cells/in.2). The adsorption capacity for water vapor on the honeycomb-K adsorbent was comparable to that on the pebble-type adsorbent, while the adsorption capacity on the honeycomb-N adsorbent was lower. The adsorption rates of honeycomb-K and honeycomb-N adsorbents were higher than that of the pebble-type adsorbent. The honeycomb-K adsorbent containing zeolite-5A showed a higher adsorption rate than that containing zeolite-4A. Thus, honeycomb-K containing zeolite-5A adsorbent could be applicable to air cleanup systems in terms of both adsorption capacity and rate.

212

Iodine removal adsorbent histories, aging and regeneration  

International Nuclear Information System (INIS)

The experience of efficiency changes with life under various test conditions is described. The adsorbents were periodically removed from both standby and continuously operating systems and tested under various test methods for residual iodine adsorption efficiency. Adsorbent from several conventional ''sampler'' cartridges versus the bulk adsorbent was also tested showing deficiency in the use of cartridge type sampling. Currently required test conditions were found inadequate to follow the aging of the adsorbent because pre-equilibration of the sample acts as a regenerant and the sample is not tested in the ''as is'' condition. The most stringent test was found to be the ambient temperature, high humidity test to follow the aging of the adsorbent. Several methods were evaluated to regenerate used adsorbents; of these high temperature steaming and partial reimpregnation were found to produce adsorbents with near identical properties of freshly prepared adsorbents

213

Uranium Recovery from Seawater: Development of Fiber Adsorbents Prepared via Atom-Transfer Radical Polymerization  

Energy Technology Data Exchange (ETDEWEB)

A novel adsorbent preparation method using atom-transfer radical polymerization (ATRP) combined with radiation-induced graft polymerization (RIGP) was developed to synthesize an adsorbent for uranium recovery from seawater. The ATRP method allowed a much higher degree of grafting on the adsorbent fibers (595 2818%) than that allowed by RIGP alone. The adsorbents were prepared with varied composition of amidoxime groups and hydrophilic acrylate groups. The successful preparation revealed that both ligand density and hydrophilicity were critical for optimal performance of the adsorbents. Adsorbents synthesized in this study showed a relatively high performance (141 179 mg/g at 49 62 % adsorption) in laboratory screening tests using a uranium concentration of ~6 ppm. This performance is much higher than that of known commercial adsorbents. However, actual seawater experiment showed impeded performance compared to the recently reported high-surface-area-fiber adsorbents, due to slow adsorption kinetics. The impeded performance motivated an investigation of the effect of hydrophilic block addition on the graft chain terminus. The addition of hydrophilic block on the graft chain terminus nearly doubled the uranium adsorption capacity in seawater, from 1.56 mg/g to 3.02 mg/g. The investigation revealed the importance of polymer chain conformation, in addition to ligand and hydrophilic group ratio, for advanced adsorbent synthesis for uranium recovery from seawater.

Saito, Tomonori [ORNL; Brown, Suree [ORNL; Chatterjee, Sabornie [ORNL; Kim, Jungseung [ORNL; Tsouris, Costas [ORNL; Mayes, Richard T [ORNL; Kuo, Li-Jung [Pacific Northwest National Laboratory (PNNL); Gill, Gary [Pacific Northwest National Laboratory (PNNL); Oyola, Yatsandra [ORNL; Janke, Christopher James [ORNL; Dai, Sheng [ORNL

2014-01-01

214

Phase transitions in adsorbed systems  

International Nuclear Information System (INIS)

Possible phase transitions in adsorbed monolayers are discussed. Nature of the transitions is divided into two classes by a parameter p which is the ratio of an adsorbate lattice constant to a substrate lattice constant. When p is greater than some special value p sub(c), the system is described by a two-component sine-Gordon model and would exhibit two Kosterlitz-Thouless like phase transitions as shown by Nelson and Halperin. On the other hand an order-disorder transition would occur for p < p sub(c). A two-component Z sub(p) model is applied to clarify the transition. It is shown in the present approach that the transition is continuous for p <= 2 while it becomes first order for 2 < p < p sub(c). (author)

215

Semiconductor laser crystallization of a-Si:H on conducting tin-oxide-coated glass for solar cell and display applications  

Science.gov (United States)

Semiconductor laser (?=805 nm) crystallization of hydrogenated amorphous silicon (a-Si:H) deposited on a low-cost fluoride-doped tin-oxide-coated glass substrate is demonstrated. X-ray diffraction confirms that the structure of the polycrystalline silicon thus formed shows (111), (220), and (311) peaks. A sharp Raman peak at 520 cm-1 further confirms the crystallization. Atomic force microscope images of a Secco-etched laser-treated sample reveal the granular structure of the poly-Si. Grains as big as ˜10 times the film thickness are readily obtained and sample as thick as 5000 Å is easily crystallized. The method can be extended to films with a thickness of several microns.

Nayak, B. K.; Eaton, B.; Selvan, J. A. A.; McLeskey, J.; Gupta, M. C.; Romero, R.; Ganguly, G.

2005-02-01

216

Comparison of Theoretically and Experimentally Determined Effects of Oxide Coatings Supplied by Fuel Additives on Uncooled Turbine-blade Temperature During Transient Turbojet-engine Operation  

Science.gov (United States)

An analysis was made to permit the calculation of the effectiveness of oxide coatings in retarding the transient heat flow into turbine blades when the combustion gas temperature of a turbojet engine is suddenly changed. The analysis is checked with experimental data obtained from a turbojet engine whose blades were coated with two different coating materials (silicon dioxide and boric oxide) by adding silicone oil and tributyl borate to the engine fuel. The very thin coatings (approximately 0.001 in.) that formed on the blades produced a negligible effect on the turbine-blade transient temperature response. With the analysis discussed here, it was possible to predict the turbine rotor-blade temperature response with a maximum error of 40 F.

Schafer, Louis J; Stepka, Francis S; Brown, W Byron

1953-01-01

217

Fabrication and Characterization of Antimony―doped Tin Oxide Coating Diatomite Conductive Material with Microporous Structure  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Porous and conductive diatomite composite materials were prepared via the calcination of the Sb―SnO2―coated diatomite precursor derived from the co―precipitation route with diatomite as the substrate. Conductivity of the samples was influenced by the Sb―SnO2 coating ratio. Calcination temperature had an impact on the crystal lattice parameters and grain sizes, hence altering the conductivity and resistivity of the composite materials. The samp...

Du Yu-cheng, Yan Jing

2011-01-01

218

Viability of oxide fiber coatings in ceramic composites for accommodation of misfit stresses  

International Nuclear Information System (INIS)

The C and BN fiber coatings used in most ceramic composites perform a less obvious but equally essential function, in addition to crack deflection; they accommodate misfit stresses due to interfacial fracture surface roughness. Coatings substituted for them must also perform that function to be effective. However, in general, oxides are much less compliant materials than C and BN, which raises the question of the feasibility of oxide substitutes. The viability of oxide coatings for accommodating misfit stresses in Nicalon fiber/SiC composites was investigated by calculating the maximum misfit stresses as functions of coating properties and geometries. Control of interfacial fracture path was also briefly considered. The implications regarding composite properties were examined by calculating properties for composites with mechanically viable oxide coatings

219

Enhanced encapsulation of metoprolol tartrate with carbon nanotubes as adsorbent  

Science.gov (United States)

A highly water-soluble antihypertensive drug, metoprolol tartrate (MT), was selected as a model drug for preparation of multi-walled carbon nanotubes (MWCNTs)-impregnated ethyl cellulose (EC) microspheres. The present investigation was aimed to increase encapsulation efficiency of MT with excellent adsorbent properties of MWCNTs. The unique surface area, stiffness, strength and resilience of MWCNTs have drawn much anticipation as carrier for highly water-soluble drugs. Carbon nanotubes drug adsorbate (MWCNTs:MT)-loaded EC microspheres were further optimized by the central composite design of the experiment. The effects of independent variables (MWCNTs:MT and EC:adsorbate) were evaluated on responses like entrapment efficiency (EE) and t 50 (time required for 50% drug release). The optimized batch was compared with drug alone EC microspheres. The results revealed high degree of improvement in encapsulation efficiency for MWCNTs:MT-loaded EC microspheres. In vitro drug release study exhibited complete release form drug alone microspheres within 15 h, while by the same time only 50-60% drug was released for MWCNTs-impregnated EC microspheres. The optimized batch was further characterized by various instrumental analyses such as scanning electron microscopy, powder X-ray diffraction and differential scanning calorimetry. The results endorse encapsulation of MWCNTs:MT adsorbate inside the matrix of EC microspheres, which might have resulted in enhanced encapsulation and sustained effect of MT. Hence, MWCNTs can be utilized as novel carriers for extended drug release and enhanced encapsulation of highly water-soluble drug, MT.

Garala, Kevin; Patel, Jaydeep; Patel, Anjali; Dharamsi, Abhay

2011-12-01

220

Removal of radioactive iodine from water using Ag2O grafted titanate nanolamina as efficient adsorbent  

International Nuclear Information System (INIS)

Highlights: ? Ag2O nanocrystals were deposited on titanate nanolamina prepared from TiOSO4. ? The composite is efficient adsorbent for removal of radioactive Iodine from water. ? The adsorbent exhibited a high capacity of 3.4 mmol of iodine per gram of adsorbent in 1 h. ? Ag2O nanocrystals are firmly anchored on the surface of the titanate lamina by coherent interface. ? The adsorbent can be recovered easily for safe disposal and suitable for column adsorption-bed. -- Abstract: Emergency treatment of radioactive material leakage and safety disposal of nuclear waste is a constant concern all along with the development of radioactive materials applications. To provide a solution, titanate with large surface area (143 m2 g?1) and a lamina morphology (the thickness of the lamina is in range of tens of nanometers) was prepared from inorganic titanium compounds by hydrothermal reactions at 433 K. Ag2O nanocrystals (5–30 nm) were deposited onto the titanate lamina. The surface of the titanate lamina has crystallographic similarity to that of Ag2O nanocrystals. Hence, the deposited Ag2O nanocrystals and titanate substrate join together at these surfaces, forming a well-matched phase coherent interface between them. Such coherence between the two phases reduces the overall energy by minimizing surface energy and anchors the Ag2O nanocrystals firmly on the external surface of the titanate structure. The composite thus obtained was applied as efficient adsorbent to remove radioactive iodine from water (one gram adsorbent can capture up to 3.4 mmol of I? anions). The composite adsorbent can be recovered easily for safe disposal. The structure changes of the titanate lamina and the composite adsorbent were monitored by various techniques. The isotherm and kinetics of iodine adsorption, competitive adsorption and column adsorption using the adsorbent were studied to assess its iodine removal abilities. The adsorbent exhibited a capacity as high as 3.4 mmol of iodine per gram of adsorbent in 1 h. Therefore, Ag2O deposited titanate lamina is an effective adsorbent for removing radioactive iodine from water

 
 
 
 
221

A cesium immobilization from an aqueous solution using the crystalline adsorber of hydrous titanium dioxide fibers  

International Nuclear Information System (INIS)

The immobilization of Cs+ ions in a CsOH solution was studied by using the adsorber of crystalline TiO2.NH2O fibers. The adsorbed cesium contents were in a compositional range of Cs sub(x)Ti6O sub(12+x/2) (1.5 16:1.5 2O3. The most stable immobilizer of Cs+ ions was obtained by sintering the mixed phases of Cs-priderite and rutile. (author)

222

Physicochemical aspects of the adsorption of sulfur dioxide by carbon adsorbents  

Science.gov (United States)

Literature data on the chemistry of the adsorption of sulfur dioxide on carbon adsorbents are surveyed and described systematically. The influence of various factors (the nature of the carbon matrix, the activation method, the chemistry of the adsorbent surfaces, temperature, the composition of the gas stream, etc.) on the sorption of SO2 by activated carbons and semicokes is examined. The possible ways in which sulfur dioxide interacts with the carbon surface are discussed. The bibliography includes 128 references.

Anurov, Sergey A.

1996-08-01

223

A novel fiber-based adsorbent technology  

Energy Technology Data Exchange (ETDEWEB)

In this Phase I Small Business Innovation Research program, Chemica Technologies, Inc. is developing an economical, robust, fiber-based adsorbent technology for removal of heavy metals from contaminated water. The key innovation is the development of regenerable adsorbent fibers and adsorbent fiber cloths that have high capacity and selectivity for heavy metals and are chemically robust. The process has the potential for widespread use at DOE facilities, mining operations, and the chemical process industry.

Reynolds, T.A. [Chemica Technologies, Inc., Bend, OR (United States)

1997-10-01

224

Molecular filtration : the study of adsorbents  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Adsorbent materials for gas purification have been studied and developed for application in many areas. It is known that a single adsorbent may not adequately control multiple contaminants. Therefore, the development of adsorbent materials has accelerated over the past two decades, and is today an area attracting a lot of attention. In view of the global environmental movement for clean air, the development of improved sorbents will help address new challenges that cannot efficiently be met w...

Twumasi, Ebenezer

2011-01-01

225

Amorphous vanadium oxide coating on graphene by atomic layer deposition for stable high energy lithium ion anodes.  

Science.gov (United States)

Uniform amorphous vanadium oxide films were coated on graphene via atomic layer deposition and the nano-composite displays an exceptional capacity of ~900 mA h g(-1) at 200 mAg(-1) with an excellent capacity retention at 1 A g(-1) after 200 cycles. The capacity contribution (1161 mA h g(-1)) from vanadium oxide only almost reaches its theoretical value. PMID:25079002

Sun, Xiang; Zhou, Changgong; Xie, Ming; Hu, Tao; Sun, Hongtao; Xin, Guoqing; Wang, Gongkai; George, Steven M; Lian, Jie

2014-09-21

226

Ecological applications of the irradiated adsorbents  

International Nuclear Information System (INIS)

Full text: In our previous works it was shown that after irradiation some adsorbents gain new interesting properties such as increasing (or decreasing) of their adsorption capacity, selectivity in relation to some gases, change of chemical bounds of gas molecules with adsorbent surface as well as other properties. We investigated a lot of adsorbents with semiconducting and dielectric properties. A high temperature superconductor was investigated also. Adsorbents were irradiated by ultraviolet (UV) and gamma - radiation, reactor (n.?) - radiation, ?-particles (E=40-50 MeV), protons ( E=30 MeV), and also He-3 ions (E-29-60 MeV). The following techniques were used: volumetric (manometrical), mass-spectrometer and IR spectroscopic methods, and also method of electronic - paramagnetic resonance (spin paramagnetic resonance) The obtained results allow to speak about creation of new adsorbents for gas purification (clearing) from harmful impurities, gas selection into components, an increasing of adsorbing surface. Thus one more advantage of the irradiated adsorbents is that they have 'memory effect', i.e. they can be used enough long time after irradiation. In laboratory conditions we built the small-sized adsorptive pump on the basis of the irradiated zeolites which are capable to work in autonomous conditions. It was found, that some of adsorbents after irradiation gain (or lose) selectivity in relation to definite gases. So, silica gel, which one in initial state does not adsorb hydrogen, after gamma irradiation it becomes active in relation to hydrogen. Some of rare earths oxides also show selectivity in relation to hydrogen and oxygen depending on a type of irradiation. Thus, it is possible to create different absorbents, depending on a solved problem, using a way or selection of adsorbents, either of radiation type and energy, as a result obtained adsorbents can be used for various ecological purposes

227

Influence of Electrolyte Chemistry on Morphology and Corrosion Resistance of Micro Arc Oxidation Coatings Deposited on Magnesium  

Science.gov (United States)

In the present work, micro arc oxidation (MAO) coatings were synthesized on magnesium substrate employing 11 different electrolyte compositions containing systematically varied concentrations of sodium silicate (Na2SiO3), potassium hydroxide (KOH), and sodium aluminate (NaAlO2). The resultant coatings were subjected to coating thickness measurement, energy dispersive spectroscopy (EDS), scanning electron microscopy (SEM), image analysis, and three-dimensional (3-D) optical profilometry. The corrosion performance of the coatings was evaluated by conducting potentiodynamic polarization tests in 3.5 wt pct NaCl solution. The inter-relationships between the electrolyte chemistry and the resulting chemistry and porosity of the coating, on one hand, and with the aqueous corrosion behavior of the coating, on the other, were studied. The changes in pore morphology and pore distribution in the coatings were found to be significantly influenced by the electrolyte composition. The coatings can have either through-thickness pores or pores in the near surface region alone depending on the electrolyte composition. The deleterious role of KOH especially when its concentration is >20 pct of total electrolyte constituents promoting the formation of large and deep pores in the coating was demonstrated. A reasonable correlation indicating the increasing pore volume implying the increased corrosion was noticed.

Rama Krishna, L.; Poshal, G.; Sundararajan, G.

2010-12-01

228

Complete braided adsorbent for marine testing to demonstrate 3g-U/kg-adsorbent  

Energy Technology Data Exchange (ETDEWEB)

ORNL has manufactured four braided adsorbents that successfully demonstrated uranium adsorption capacities ranging from 3.0-3.6 g-U/kg-adsorbent in marine testing at PNNL. Four new braided and leno woven fabric adsorbents have also been prepared by ORNL and are currently undergoing marine testing at PNNL.

Janke, Chris [ORNL; Yatsandra, Oyola [ORNL; Mayes, Richard [ORNL; none,; Gill, Gary [PNNL; Li-Jung, Kuo [PNNL; Wood, Jordana [PNNL; Sadananda, Das [ORNL

2014-04-30

229

Removal of radioactive iodine from water using Ag2O grafted titanate nanolamina as efficient adsorbent.  

Science.gov (United States)

Emergency treatment of radioactive material leakage and safety disposal of nuclear waste is a constant concern all along with the development of radioactive materials applications. To provide a solution, titanate with large surface area (143 m(2)g(-1)) and a lamina morphology (the thickness of the lamina is in range of tens of nanometers) was prepared from inorganic titanium compounds by hydrothermal reactions at 433 K. Ag(2)O nanocrystals (5-30 nm) were deposited onto the titanate lamina. The surface of the titanate lamina has crystallographic similarity to that of Ag(2)O nanocrystals. Hence, the deposited Ag(2)O nanocrystals and titanate substrate join together at these surfaces, forming a well-matched phase coherent interface between them. Such coherence between the two phases reduces the overall energy by minimizing surface energy and anchors the Ag(2)O nanocrystals firmly on the external surface of the titanate structure. The composite thus obtained was applied as efficient adsorbent to remove radioactive iodine from water (one gram adsorbent can capture up to 3.4 mmol of I(-) anions). The composite adsorbent can be recovered easily for safe disposal. The structure changes of the titanate lamina and the composite adsorbent were monitored by various techniques. The isotherm and kinetics of iodine adsorption, competitive adsorption and column adsorption using the adsorbent were studied to assess its iodine removal abilities. The adsorbent exhibited a capacity as high as 3.4 mmol of iodine per gram of adsorbent in 1h. Therefore, Ag(2)O deposited titanate lamina is an effective adsorbent for removing radioactive iodine from water. PMID:23313892

Bo, Arixin; Sarina, Sarina; Zheng, Zhanfeng; Yang, Dongjiang; Liu, Hongwei; Zhu, Huaiyong

2013-02-15

230

NOx adsorber and method of regenerating same  

Science.gov (United States)

New technologies, such as NOx adsorber catalytic converters, are being used to meet increasingly stringent regulations on undesirable emissions, including NOx emissions. NOx adsorbers must be periodically regenerated, which requires an increased fuel consumption. The present disclosure includes a method of regenerating a NOx adsorber within a NOx adsorber catalytic converter. At least one sensor positioned downstream from the NOx adsorber senses, in the downstream exhaust, at least one of NOx, nitrous oxide and ammonia concentrations a plurality of times during a regeneration phase. The sensor is in communication with an electronic control module that includes a regeneration monitoring algorithm operable to end the regeneration phase when a time rate of change of the at least one of NOx, nitrous oxide and ammonia concentrations is after an expected plateau region begins.

Endicott, Dennis L. (Peoria, IL); Verkiel, Maarten (Metamora, IL); Driscoll, James J. (Dunlap, IL)

2007-01-30

231

Fluorescence dynamics of microsphere-adsorbed sunscreens  

Science.gov (United States)

Sunscreens are generally oily substances which are prepared in organic solvents, emulsions or dispersions with micro- or nanoparticles. These molecules adsorb to and integrate into skin cells. In order to understand the photophysical properties of the sunscreen, we compare steady-state and time-resolved fluorescence in organic solvent of varying dielectric constant ? and adsorbed to polystyrene microspheres and dispersed in water. Steady-state fluorescence is highest and average fluorescence lifetime longest in toluene, the solvent of lowest ?. However, there is no uniform dependence on ?. Sunscreens PABA and padimate-O show complex emission spectra. Microsphere-adsorbed sunscreens exhibit highly non-exponential decay, illustrative of multiple environments of the adsorbed molecule. The heterogeneous fluorescence dynamics likely characterizes sunscreen adsorbed to cells.

Krishnan, R.

2005-03-01

232

Fabrication and Characterization of Antimony―doped Tin Oxide Coating Diatomite Conductive Material with Microporous Structure  

Directory of Open Access Journals (Sweden)

Full Text Available Porous and conductive diatomite composite materials were prepared via the calcination of the Sb―SnO2―coated diatomite precursor derived from the co―precipitation route with diatomite as the substrate. Conductivity of the samples was influenced by the Sb―SnO2 coating ratio. Calcination temperature had an impact on the crystal lattice parameters and grain sizes, hence altering the conductivity and resistivity of the composite materials. The samples were characterized by means of X―ray diffraction (XRD), scanning electron microscope (SEM), transmission electron microscope (TEM), energy―dispersive X―ray spectrometry (EDS), N2 adsorption―desorption measurement (BET), and Fourier transform infrared spectrometry (FT―IR). The conductive performance of the samples was determined using a Four―Point Probe Meter apparatus. It is shown that the mesoporous (pore diameter = 6 nm) sample with n(Sn)/n(Sb)=8/1 and a Sb―SnO2 coating ratio of 25.8wt% derived from calcination at 700¡?xhibited the lowest resistivity of 22 ?·cm.

DU Yu-Cheng, YAN Jing, MENG Qi, LI Yang, DAI Hong-Xing

2011-10-01

233

Biodegradable adsorbents for aquatic oil spills: Adsorbent capabilities and biodegradation rates  

International Nuclear Information System (INIS)

Polypropylene fibers are the most used type of adsorbent material for oil spill cleanup, yet disposal of these fibers after they are oil-soaked presents a problem since they are not biodegradable and either have to be incinerated or placed in special landfills. Ex-situ biodegradation of used adsorbents is being investigated as a means of circumventing those problems. Biodegradable natural-fiber adsorbents including cotton and wool fibers were tested to determine their oil adsorbing capacities as compared to polypropylene adsorbents. Experiments were also conducted to study degradation of the adsorbent and the adsorbed oil. The oil adsorbing capacities of all fibers tested were similar except for raw cotton, whose capacity was considerably higher. In closed environments where optimum conditions for degradation could be provided and controlled, cotton or wool fiber adsorbents could be destroyed by microbial activity within several weeks. The adsorbents were degraded first and their adsorbed oil released. This oil could be separated and recovered. Complete anaerobic degradation of a sweet crude oil could be accomplished within six months, while diesel fuel could be degraded within one week. 8 refs.,. 3 figs., 1 tab

234

Controlling catalytic selectivity on metal nanoparticles by direct photoexcitation of adsorbate-metal bonds.  

Science.gov (United States)

Engineering heterogeneous metal catalysts for high selectivity in thermal driven reactions typically involves the synthesis of nanostructures with well-controlled geometries and compositions. However, inherent relationships between the energetics of elementary steps limit the control of catalytic selectivity through these approaches. Photon excitation of metal catalysts can induce chemical reactivity channels that cannot be accessed using thermal energy, although the potential for targeted activation of adsorbate-metal bonds is limited because the processes of photon absorption and adsorbate-metal bond photoexcitation are typically separated spatially. Here, we show that the use of sub-5-nanometer metal particles as photocatalysts enables direct photoexcitation of hybridized adsorbate-metal states as the dominant mechanism driving photochemistry. Activation of targeted adsorbate-metal bonds through direct photoexcitation of hybridized electronic states enabled selectivity control in preferential CO oxidation in H2 rich streams. This mechanism opens new avenues to drive selective catalytic reactions that cannot be achieved using thermal energy. PMID:25111312

Kale, Matthew J; Avanesian, Talin; Xin, Hongliang; Yan, Jun; Christopher, Phillip

2014-09-10

235

Structural and phase investigations of oxide coatings of TiO2 and Al2O3+13wt.%TiO2 after remelting  

Directory of Open Access Journals (Sweden)

Full Text Available Purpose: The purpose of this work was a microstructural and phase analysis of oxide layers remelted with TIG welding machine and by means of modified TIG method.Design/methodology/approach: The scope of investigations encompassed microstructural and phase assessment of oxide layers after remelting and alloying. Surface treatment was performed by means of TIG welding method and its modified version.Findings: Investigations of remelted coatings enabled determination of effect of the treatment on the structure and nature of phase transformations.Research limitations/implications: Further investigations with use of transmission electron microscopy will make it possible to observe the microstructures and obtain additional information about morphology of phases.Practical implications: Oxide coatings are one of the main components in coatings which are used under conditions of intensive wear and influence of corrosion agents.Originality/value: Modification of single-torch welding method was a solution to a problem of remelting of non-conducting ceramic coatings.

A. Dudek

2008-09-01

236

Adsorption of nickel and copper onto natural iron oxide-coated sand from aqueous solutions: Study in single and binary systems  

International Nuclear Information System (INIS)

Natural iron oxide-coated sand (NCS), extracted from the iron ore located in North-West of Tunisia, was employed to investigate its capacity to remove copper and nickel from aqueous solutions. The aim of this work was to characterize the considered sorbent (NCS) and to assess the possibility of removing nickel and copper from aqueous solutions by this sorbent. The effects of agitation time, pH, initial metal ion concentration and temperature on the removal of these metals were studied. In order to study the sorption isotherm, two equilibrium models, the Freundlich and Langmuir isotherms, were analyzed. The effect of solution pH on the adsorption onto NCS was studied in the pH range from 2 to 7 and 2 to 9 for copper and nickel respectively. The adsorption was endothermic and the computation of the parameters, ?Ho, ?So and ?Go, indicated that the interactions were thermodynamically favourable. Experiments with Cu and Ni adsorption measured together showed that Cu severely interfered with Ni adsorption to the NCS and vice versa under the conditions of the two coexisted ions adsorption

237

Adsorption of nickel and copper onto natural iron oxide-coated sand from aqueous solutions: Study in single and binary systems  

Energy Technology Data Exchange (ETDEWEB)

Natural iron oxide-coated sand (NCS), extracted from the iron ore located in North-West of Tunisia, was employed to investigate its capacity to remove copper and nickel from aqueous solutions. The aim of this work was to characterize the considered sorbent (NCS) and to assess the possibility of removing nickel and copper from aqueous solutions by this sorbent. The effects of agitation time, pH, initial metal ion concentration and temperature on the removal of these metals were studied. In order to study the sorption isotherm, two equilibrium models, the Freundlich and Langmuir isotherms, were analyzed. The effect of solution pH on the adsorption onto NCS was studied in the pH range from 2 to 7 and 2 to 9 for copper and nickel respectively. The adsorption was endothermic and the computation of the parameters, {delta}H{sup o}, {delta}S{sup o} and {delta}G{sup o}, indicated that the interactions were thermodynamically favourable. Experiments with Cu and Ni adsorption measured together showed that Cu severely interfered with Ni adsorption to the NCS and vice versa under the conditions of the two coexisted ions adsorption.

Boujelben, N. [Laboratoire Eau Energie et Environnement, departement de genie geologique, Ecole Nationale d' Ingenieurs de Sfax, BP W 3038 Sfax (Tunisia)], E-mail: nesrine.boujelben@tunet.tn; Bouzid, J. [Laboratoire Eau Energie et Environnement, departement de genie geologique, Ecole Nationale d' Ingenieurs de Sfax, BP W 3038 Sfax (Tunisia)], E-mail: Jalel.bouzid@tunet.tn; Elouear, Z. [Laboratoire Eau Energie et Environnement, departement de genie geologique, Ecole Nationale d' Ingenieurs de Sfax, BP W 3038 Sfax (Tunisia)], E-mail: zouheir.elouaer@tunet.tn

2009-04-15

238

Effects of cathodic voltages on structure and wear resistance of plasma electrolytic oxidation coatings formed on aluminium alloy  

Science.gov (United States)

Plasma electrolytic oxidation (PEO) coatings were prepared on aluminium alloy using pulsed bipolar power supply at constant anodic voltage and different cathodic voltages. The samples were prepared to attain the same coating thickness by adjusting the processing time. The scanning electron microscope (SEM), energy dispersive spectrometer (EDS), X-ray diffraction (XRD) and tribometer were employed to investigate the microstructure, element content, phase composition and wear resistance of the coatings respectively. It was found that the coating growth rate enhanced obviously and the coatings exhibited a more compact structure with thicker inner layer and lower surface roughness when the cathodic voltage increased. The coatings were mainly composed of crystalline ?-Al2O3 and amorphous silicate oxides and their relative content changed with the cathodic voltage. The wear resistance of the coatings improved significantly with the increase of cathodic voltage.

Li, Qingbiao; Liang, Jun; Liu, Baixing; Peng, Zhenjun; Wang, Qing

2014-04-01

239

Inorganic chemically active adsorbents (ICAAs)  

Energy Technology Data Exchange (ETDEWEB)

Oak Ridge National Laboratory (ORNL) researchers are developing a technology that combines metal chelation extraction technology and synthesis chemistry. They begin with a ceramic substrate such as alumina, titanium oxide or silica gel because they provide high surface area, high mechanical strength, and radiolytic stability. One preparation method involves silylation to hydrophobize the surface, followed by chemisorption of a suitable chelation agent using vapor deposition. Another route attaches newly designed chelating agents through covalent bonding by the use of coupling agents. These approaches provide stable and selective, inorganic chemically active adsorbents (ICAAs) tailored for removal of metals. The technology has the following advantages over ion exchange: (1) higher mechanical strength, (2) higher resistance to radiation fields, (3) higher selectivity for the desired metal ion, (4) no cation exchange, (5) reduced or no interference from accompanying anions, (6) faster kinetics, and (7) easy and selective regeneration. Target waste streams include metal-containing groundwater/process wastewater at ORNL`s Y-12 Plant (multiple metals), Savannah River Site (SRS), Rocky Flats (multiple metals), and Hanford; aqueous mixed wastes at Idaho National Engineering Laboratory (INEL); and scrubber water generated at SRS and INEL. Focus Areas that will benefit from this research include Mixed Waste, and Subsurface Contaminants.

Ally, M.R. [Oak Ridge National Lab., TN (United States); Tavlarides, L.

1997-10-01

240

Di(isothiocyanato)bis(4-methyl-4’-vinyl-2,2’-bipyridine) Ruthenium(II) Films Deposited on Titanium Oxide-Coated, Fluorine-Doped Tin Oxide for an Efficient Solar Cell  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Dye-sensitized titanium oxide electrodes were prepared by immobilizing a novel ruthenium complex, di(isothiocy- anato)bis(4-methyl-4’-vinyl-2,2’-bipyridine)ruthenium(II) [(NCS)2(mvbpy)2Ru(II)] or the ruthenium complex/sodium 4-vinylbenzenesulfonate onto the surface of a titanium oxide-coated, fluorine-doped tin oxide (TiO2/FTO) electrode through a new electrochemically initiated film formation metho...

Yi Liu; Ryuichi Sugimoto; Katsuhiro Sumi

2013-01-01

 
 
 
 
241

Heat transfer to the adsorbent in solar adsorption cooling device  

Science.gov (United States)

The article deals with design and construction of solar adsorption cooling device and with heat transfer problem in adsorber. The most important part of adsorption cooling system is adsorber/desorber containing adsorbent. Zeolith (adsorbent) type was chosen for its high adsorption capacity, like a coolant was used water. In adsorber/desorber occur, at heating of adsorbent, to heat transfer from heat change medium to the adsorbent. The time required for heating of adsorber filling is very important, because on it depend flexibility of cooling system. Zeolith has a large thermal resistance, therefore it had to be adapted the design and construction of adsorber. As the best shows the tube type of adsorber with double coat construction. By this construction is ensured thin layer of adsorbent and heating is quick in all volume of adsorbent. The process of heat transfer was experimentally measured, but for comparison simulated in ANSYS, too.

Pilat, Peter; Patsch, Marek; Papucik, Stefan; Vantuch, Martin

2014-08-01

242

Composites  

Science.gov (United States)

It is commonly known that the properties of sintered materials are strongly related to technological conditions of the densification process. This paper shows the sintering behavior of a NiAl-Al2O3 composite, and its individual components sintered separately. Each kind of material was processed via the powder metallurgy route (hot pressing). The progress of sintering at different stages of the process was tested. Changes in the microstructure were examined using scanning and transmission electron microscopy. Metal-ceramics interface was clean and no additional phases were detected. Correlation between the microstructure, density, and mechanical properties of the sintered materials was analyzed. The values of elastic constants of NiAl/Al2O3 were close to intermetallic ones due to the volume content of the NiAl phase particularly at low densities, where small alumina particles had no impact on the composite's stiffness. The influence of the external pressure of 30 MPa seemed crucial for obtaining satisfactory stiffness for three kinds of the studied materials which were characterized by a high dense microstructure with a low number of isolated spherical pores.

Chmielewski, M.; Nosewicz, S.; Pietrzak, K.; Rojek, J.; Strojny-N?dza, A.; Mackiewicz, S.; Dutkiewicz, J.

2014-11-01

243

Properties of water adsorbed in porous silica aerogels  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Silica aerogels have been prepared by hydrolysis and condensation of sols of composition TMOS-methanol-H2O with molar ratio TMOS:H2O=4:1 and volume ratio TMOS:methanol=0.2; 0.3; 0.4 and 0.6. Their true and apparent densities, BET surface area, total pore volume and pore size distribution have been systematically investigated as a function of densification heat treatment. The relaxation properties of water adsorbed on the highly reactive surface have been studied by dielectric and nuclear magn...

Da Silva, Adao A.; Donoso, Jose P.; Aegerter, Michel A.

1992-01-01

244

Cryovacuum helium adsorption by microporous carbon adsorbents  

International Nuclear Information System (INIS)

Various carbon adsorbents (carbon carbonized at different temperatures, activated carbon with different combustions) adsorbed helium at 20.4 K according to the V = KPsup(n) law, the Freundlich equation, where the slope, n, is close to 1. For adsorbents with a relatively large volume of ultramicropores n1 (adsorption volume increases with pressure more rapidly than would be expected from the linear law). Thus there is an identical correlation between the distribution of pore volume according to size and the nature of the deviation from the linear law of helium isotherm adsorption at 20.40K

245

Effect of Micro-Arc Oxidation Coatings on Corrosion Resistance and Mechanical Properties of Closed-Cell Aluminum Foams  

Science.gov (United States)

Micro-arc oxidation (MAO) coatings were prepared on closed-cell aluminum foams. The microstructure, elemental distribution and phase composition of the MAO coatings were analyzed by scanning electron microscopy (SEM), energy-dispersive spectroscopy (EDS) and X-ray diffraction (XRD), respectively. The corrosion resistances and compressive properties of the uncoated and coated aluminum foams were studied by electrochemical polarization test and mechanical test, respectively. The results show that the MAO coatings cover the surfaces of closed-cell aluminum foams. The average thickness of the MAO coatings is 7 ?m. The MAO coatings are mainly composed of ?-Al2O3 phase. The corrosion resistances of the closed-cell aluminum foams are improved by MAO treatment. The as-received foams show a low corrosion potential (-1.36 V), on contrary, the MAO coated foams get an increase corrosion potential (-0.78 V). But the MAO coated foams show the marginal variation in compressive strengths when the thickness of the coatings could be negligible compared with the total thickness of the foams.

Zhu, Xianyong; Liu, Jiaan

2013-10-01

246

Structure and Property of Micro-arc Oxidation Coating Modified by Laser Melting and Solidifying on Aluminum Alloy  

Directory of Open Access Journals (Sweden)

Full Text Available In order to improve performance and microstructure of micro-arc oxidation (MAO coating, especially loose and porous characteristic, a laser melting and solidifying process (LSM was introduced. Two kinds of samples were prepared: (1 MAO coatings, 18 ?m average thickness, were produced on 6082 aluminum alloy by bipolar current pulse in Na2SiO3-KOH solution. (2 a melting process using a Nd:YAG laser was employed to modify above-mentioned MAO coatings to obtain MAO+LSM coating. Microstructure of two kinds of coatings (MAO coating and MAO+LSM coating were examined by scanning electron microscopy. X-ray diffraction was used to determine the phase composition of the coatings. Coating hardness was tested by ultra-micro hardness tester, and corrosion performance was investigated by polarization test instrument. The results show that the MAO+LSM coating is composed of dense layer, intermediate layer and melting layer from inside to surface. The loose layer of MAO film is replaced by a dense and low porosity melting layer after LSM treatment. The occupancy of ?-Al2O3 phase in MAO+LSM is improved compared with MAO coating. Hardness and anticorrosion performance of MAO+LSM coating are also further strengthened while the remelted coating keeps the same binding manner as MAO coating.

YU Jie, WEI Dong-Bo, WANG Yan, L¨¹ Peng-Xiang, DI Shi-Chun

2013-08-01

247

The phase and microstructural analysis of protective oxide coatings on molybdenum; Phasen- und Gefuegeanalyse in Oxidationsschutzschichten fuer Molybdaen  

Energy Technology Data Exchange (ETDEWEB)

Due to their high sensitivity to oxygen, the use of refractory metals requires an effective protection against oxidation. In the case of molybdenum this is achieved by using a silicon and boron based coating commercially marketed under the trade name SIBOR {sup registered}. In the moduction of a SIBOR {sup registered} -coating, a mixture of Si, B and C is plasma sprayed in air onto the Mo-surface to be protected and subsequently annealed in hydrogen. Previous investigations have shown that in doing so a stationary coating of Mo-borides and Mo-silicides is formed. However, the exact phase arrangement and composition has until now remained unclear. Energy dispersive X-ray spectroscopy (EDS) in the scanning electron microscope (SEM) is able to analyse the silicides in SIBOR {sup registered}, although due to the overlapping of the Mo-and B-spectral partial a clear identification of the borides was not possible. Using a combination of electron back scatter diffraction (EBSD) and wavelength dispersive X-ray spectroscopy (WDS) it is, however, shown that SIBOR {sup registered} is made up of a series of sublayers of Mo{sub 2}B and MoB followed by Mo{sub 5}Si{sub 3} and MoSi{sub 2}, and that the other phases of the Mo-Si-B ternary system, i.e. Mo{sub 3}Si and Mo{sub 5}SiB{sub 2}(T{sub 2}), do not occur. Notably, the two borides and the Mo{sub 5}Si{sub 3} exhibit a structure which is polycrystalline in the lateral direction yet normal to the surface forms of only a single layer of crystallites. In contrast, the final MoSi{sub 2}-layer has a polycrystalline structure both in the lateral and in the normal directions. Furthermore, Mo{sub 5}Si{sub 3} and MoSi{sub 2} both exhibit marked textures. (orig.)

Traxler, Hannes; Joerg, Roland; Zabernig, M; Sigl, L.S. [PLANSEE SE, Reutte /Tirol (Austria)

2011-07-01

248

Effect of high temperature oxidation prefab film on formation of micro-arc oxidation coatings on 6061aluminum alloy  

Science.gov (United States)

Ceramic coatings were formed by micro-arc oxidation (MAO) on 6061aluminum alloy with and without a high temperature oxidation prefab film under a constant voltage. The effect of the high temperature oxidation prefab film on the initial stage of growth process of the MAO ceramic coatings was studied in this paper. The results showed that the prefab film decreased the arc starting voltage and the arc starting time of the micro-arc oxidation, and promoted the evolution processes of the micro-discharge and the surface morphology of the coating. The prefab film and electrolyte composition, especially element P, participated in the formation of the coatings. The growth process of the micro-arc oxidation ceramic coatings on specimens with the prefab film consists of four steps. The first step is the formation of grain type of oxide lumps, the second step is the spread of the lumps like little worms along the specimen surface, the third step is the formation of many network areas with a number of linear materials like little worms, and the fourth step is the development of network areas into a continuous layer. However, at the same period, the growth process of micro-arc oxidation ceramic coatings on the specimens without the prefab film consists of two steps. The first step is the formation of a little grain type of oxide lumps, and the second step is the increase of the number of grain type of oxide lumps and the expansion of the lumps like little worms in line along the surface of specimens.

Dejiu, Shen; Jie, Zou; Lailei, Wu; Fangfei, Liu; Guolong, Li; Jingrui, Cai; Donglei, He; Haojie, Ma; Guirong, Jiang

2013-01-01

249

Effect of reactive element oxide coatings on the high temperature oxidation behavior of a FeCrAl alloy  

International Nuclear Information System (INIS)

This paper reports that thin coatings of nitrate-converted oxides of Y, Zr, Hf, Ce, La, Ca, and Al have been applied to the surface of a Fe-18 weight percent (w/o) Cr-5 w/o Al alloy by hot-dipping. The influence of these coatings on the oxidation behavior of the alloy was studied at 1100 and 1200 degrees C. Results were also compared with the oxidation of a 1 w/o Hf-containing alloy of the same base composition, with or without the application of selected coatings. It was found that all of the coated FeCrAl samples, apart from that coated with aluminum oxide, developed extremely convoluted Al2O3 scales. Oxide ridges several times larger than those formed on the untreated alloy developed at the oxidation temperature. These convoluted scales showed good spallation resistance after isothermal testing, but failed under thermal cyclic conditions. A thin layer of sulfur was found everywhere at the scale/alloy interface. The primary effect of the surface coatings was to increase the number of buckles in the oxide at the early stage of oxidation. Growth of the buckled oxide into large ridges took place by way of aluminum vapor phase transport and oxide lateral growth. The results are discussed in relation to the effect of reactive elements in improving scale adhesion, and it is suggested that the mechanisms governing this effect may be different for Al2O3-forming and for Cr2O3-forming alloys

250

Electro-Mechanical Coupling of Indium Tin Oxide Coated Polyethylene Terephthalate ITO/PET for Flexible Solar Cells  

Indium tin oxide (ITO) is the most widely used transparent electrode in flexible solar cells because of its high transparency and conductivity. But still, cracking of ITO on PET substrates due to tensile loading is not fully understood and it affects the functionality of the solar cell tremendously as ITO loses its conductivity. Here, we investigate the cracking evolution in ITO/PET exposed to two categories of tests. Monotonous tensile testing is done in order to trace the crack propagation in ITO coating as well as determining a loading range to focus on during our study. Five cycles test is also conducted to check the crack closure effect on the resistance variation of ITO. Analytical model for the damage in ITO layer is implemented using the homogenization concept as in laminated composites for transverse cracking. The homogenization technique is done twice on COMSOL to determine the mechanical and electrical degradation of ITO due to applied loading. Finally, this damage evolution is used for a simulation to predict the degradation of ITO as function in the applied load and correlate this degradation with the resistance variation. Experimental results showed that during unloading, crack closure results in recovery of conductivity and decrease in the overall resistance of the cracked ITO. Also, statistics about the crack spacing showed that the cracking pattern is not perfectly periodical however it has a positively skewed distribution. The higher the applied load, the less the discrepancy in the crack spacing data. It was found that the cracking mechanism of ITO starts with transverse cracking with local delamination at the crack tip unlike the mechanism proposed in the literature of having only cracking pattern without any local delamination. This is the actual mechanism that leads to the high increase in ITO resistance. The analytical code simulates the damage evolution in the ITO layer as function in the applied strain. This will be extended further to correlate the damage to the resistance variation in following studies.

Saleh, Mohamed A.

2013-05-15

251

Scattering studies of pluronics adsorbed on laponite  

International Nuclear Information System (INIS)

Full text: The synthetic clay laponite is a versatile product in the colloid industry. It can form gel structures at low concentrations, which give rise to technologically interesting rheological properties, hence its use as a thickener in paint, emulsifying agents, etc. However these properties may be modified by the addition of adsorbing polymers. In this study we examined the effects of adsorbed Pluronic triblock copolymers [(poly(ethylene oxide)-poly(propylene oxide)-poly(ethylene oxide)] layers on the structure and interactions of a laponite dispersion. Contrast variation small-angle neutron scattering (SANS) measurements were used to characterise the layer size and the amount of adsorbed polymer. These experiments show that polymer is present not only on the face of the clay particle, but extends or 'wraps' over the edge as well. Moreover, the trends in layer size and adsorbed amount are consistent with Marques and Joannys scaling theory for block copolymer adsorption

252

New liquid waste control with tannin adsorbent  

International Nuclear Information System (INIS)

Since 1971, the Mitsubishi Nuclear Fuel Co., Ltd. (MNF) has been fabricating PWR fuels and developing related technology and processes. In the UF6 reconversion lines of MNF, the ammonium diuranate (ADU) process has been operating and the newly developed process of liquid waste treatment was installed last year. The characteristic of this process is to use insoluble tannin adsorbent which has been developed by MNF. The tannin adsorbent is not only an effective means to adsorb heavy metals such as uranium and plutonium but is also easy to incinerate at low temperature. Control of radioactive liquid waste from nuclear facilities is generally implemented by co-precipitation. However, it produces secondary wastes such as noncombustible materials which include radionuclides and it is anticipated that the storage and disposal of those wastes will be at high cost. Those are the reasons why tannin adsorbent has an advantage, and why MNF develops it. (author)

253

PERVAPORATION USING ADSORBENT-FILLED MEMBRANES  

Science.gov (United States)

Membranes containing selective fillers, such as zeolites and activated carbon, can improve the separation by pervaporation. Applications of adsorbent-filled membranes in pervaporation have been demonstrated by a number of studies. These applications include removal of organic co...

254

Spherical Adsorbers and Catalysts from Aluminium Oxides  

International Science & Technology Center (ISTC)

Development of Multiaimed Low-Waste Technology of Production of Spherical Aluminium Oxide and Catalysts and Adsorbents on its Base which Allows to Solve Urgent Ecological Problems in Various Branches of Industry

255

Adsorbate interactions and poisoning on Cr(110)  

International Nuclear Information System (INIS)

Spectroscopic studies of carbon monoxide and oxygen chemisorption on Cr(110) below 150K have revealed direct quantitative evidence of co-adsorbate interactions which affect molecular dissociation pathways

256

IR investigations of surfaces and adsorbates  

Science.gov (United States)

Synchrotron infrared reflection-absorption measurements on single crystal metal surfaces with adsorbates have led to the determination of many key parameters related to the bonding vibrational modes and the dynamics of adsorbates. In particular, energy couplings between electrons and adsorbate motion have been shown to be a dominant mechanism on metal surfaces. Excellent agreement has been obtained with calculations for many of the observations, and the synergy between theory and experiment has led to a deeper understanding of the roles of electrons and phonons in determining the properties of interfaces and their roles in phenomena as diverse as friction, lubrication, catalysis and adhesion. Nonetheless, as the experiments are pushed harder, to describe such effects as co-adsorbed systems, disagreements continue to challenge the theory and our comprehension also is still evolving.

Williams, Gwyn P.

2001-12-01

257

IR investigations of surfaces and adsorbates  

CERN Document Server

Synchrotron infrared reflection-absorption measurements on single crystal metal surfaces with adsorbates have led to the determination of many key parameters related to the bonding vibrational modes and the dynamics of adsorbates. In particular, energy couplings between electrons and adsorbate motion have been shown to be a dominant mechanism on metal surfaces. Excellent agreement has been obtained with calculations for many of the observations, and the synergy between theory and experiment has led to a deeper understanding of the roles of electrons and phonons in determining the properties of interfaces and their roles in phenomena as diverse as friction, lubrication, catalysis and adhesion. Nonetheless, as the experiments are pushed harder, to describe such effects as co-adsorbed systems, disagreements continue to challenge the theory and our comprehension also is still evolving.

Gwyn, W

2001-01-01

258

Properties and selection criteria for adsorbents  

International Nuclear Information System (INIS)

The paper gives a survey of the most important industrial adsorbents and of their suitability for different purposes. With special consideration of activated carbon, the properties and characteristic data are discussed which are used for assessing adsorbents. These, among other things, are as follows: specific surface area, pore size distribution, adsorption isotherms, hydrophobic properties, catalytic properties, chemical resistance, heat resistance, particle size and hardness. (orig.)

259

Regenerable activated bauxite adsorbent alkali monitor probe  

Science.gov (United States)

A regenerable activated bauxite adsorber alkali monitor probe for field applications to provide reliable measurement of alkali-vapor concentration in combustion gas with special emphasis on pressurized fluidized-bed combustion (PFBC) off-gas. More particularly, the invention relates to the development of a easily regenerable bauxite adsorbent for use in a method to accurately determine the alkali-vapor content of PFBC exhaust gases.

Lee, Sheldon H. D. (Willowbrook, IL)

1992-01-01

260

Chemical characterization of porphyrin adsorbed on anion modified copper electrodes: An SXPS study  

Energy Technology Data Exchange (ETDEWEB)

Several Anions adsorb specifically from aqueous solution on copper electrodes. In case of copper single crystals, the electrode acts as a template for the anion adsorption and well ordered superstructures are observable. These, negatively charged, anion layers are used as secondary templates for the adsorption of cationic organic molecules. The adsorption of TMPyP (Tetramethylpyridiniumporphyrin) has been extensively studied by in-situ EC-STM which provides structural and electrochemical data, but there are less data about the chemical composition of the adsorbate layer. We have characterized (ex-situ) the chemical composition of the adsorbed TMPyP molecules on halide and sulfide modified Cu(100) and Cu(111) using XPS at the synchrotron radiation facility BESSY II.

Breuer, Stephan; Gentz, Knud; Pham, Duc Thanh; Phan, Thanh Hai; Wandelt, Klaus [Universitaet Bonn, Institut fuer Physikalische und Theoretische Chemie, Wegelerstrasse 12, D-53115 Bonn (Germany); Mayer, Thomas [Technische Universitaet Darmstadt, FB Materialwissenschaft, Petersenstrasse 23, D-64284 Darmstadt (Germany); Broekmann, Peter [Universitaet Bern (Switzerland). Departement fuer Chemie und Biochemie

2010-07-01

 
 
 
 
261

Indium tin oxide-coated glass modified with reduced graphene oxide sheets and gold nanoparticles as disposable working electrodes for dopamine sensing in meat samples  

Science.gov (United States)

Sensitive, rapid, and accurate detection of dopamine (DA) at low cost is needed for clinical diagnostic and therapeutic purposes as well as to prevent illegal use of DA in animal feed. We employed a simple approach to synthesize reduced graphene oxide sheets (rGOS) and gold nanoparticles (AuNPs) at room temperature on indium tin oxide-coated glass (ITO) slides as disposable working electrodes for sensing DA. Graphene oxide (GO) was directly reduced on ITO to remove oxygenated species via a rapid and green process without using chemical reducing reagents. AuNPs were electrochemically deposited in situ on rGOS-ITO with fairly uniform density and size. The sensitivity of the AuNPs-rGOS-ITO sensor for DA detection is 62.7 ?A mM-1 cm-2 with good selectivity against common electrochemically interfering species such as ascorbic acid (AA) and uric acid (UA), and the detection limit measured by differential pulse voltammetry (DPV), at a signal-noise ratio of 3, was 6.0 × 10-8 M. The electrochemical catalysis of DA was proven to be a surface process with an electron transfer coefficient (?) of 0.478 and a rate constant (ks) of 1.456 s-1. It correlates well with the conventional UV-vis spectrophotometric approach (R = 0.9973) but with more than thrice the dynamic range (up to 4.5 mM). The sensor also exhibited good stability and capability to detect DA in beef samples, and thus is a promising candidate for simple and inexpensive sub-nanomolar detection of DA, especially in the presence of UV-absorbing compounds.

Yang, Jiang; Strickler, J. Rudi; Gunasekaran, Sundaram

2012-07-01

262

Pillared smectite clay coatings for ceramic-matrix composites  

Energy Technology Data Exchange (ETDEWEB)

This paper describes a novel route for the low-temperature formation of mullite, from pillared smectite clay precursors, for use as fiber coatings in ceramic-matrix composites. In particular, alumina-pillared bentonite converts in part to mullite at the unusually low temperature of about 800 C. The clay precursors display excellent film-forming capability and have been coated onto silicon carbide fibers. Mechanical tests on composites of the coated fibers and a borosilicate glass demonstrate their success as debond coatings, suggesting that this approach is a viable and simple route to oxide coatings for fibers.

Jagota, S.; Harmer, M.A.; Lemon, M.F.; Jagota, A.; McCarron, E.M. III. [E.I. du Pont de Nemours and Company, Wilmington, DE (United States). Central Research and Development

1995-08-01

263

Novel Fiber-Based Adsorbent Technology; FINAL  

International Nuclear Information System (INIS)

The overall of this Department of Energy (DOE) Phase II SBIR program was to develop a new class of highly robust fiber-based adsorbents for recovery of heavy metals from aqueous waste-streams. The fiber-based adsorbents,when commercialized,will be used for clean up metals in aqueous waste-streams emanating from DOE facilities,industry,mining,and groundwater-cleanup operations.The amount of toxic waste released by these streams is of great significance.The U.S.Environment Protection Agency (EPA) reports that in 1990 alone,4.8 billion pounds of toxic chemicals were released into the environment.Of this waste,the metals-containing waste was the second largest contributor,representing 569 million pounds. This report presents the results of the Phase II program,which successfully synthesized noval fiber-based adsorbents for the removal of Group 12 metals(i.e.mercury),Group 14 metals (lead),and Group 10 metals(platinum and palladium) from contaminated groundwater and industrial waste streams.These fiber-based adsorbents are ideally suited for the recovery of metal ions from aqueous waste streams presently not treatable due to the degrading nature of corrosive chemicals or radioactive components in the feed stream. The adsorbents developed in this program rely on chemically resistant and robust carbon fibers and fabrics as supports for metal-ion selective ligands.These adsorbents demonstrate loading capacities and selectivities for metal ions exceeding those of conventional ion-exchange resins.The adsorbents were also used to construct filter modules that demonstrate minimal fouling,minimal compaction,chemical and physical robustness,and regeneration of metal loading capacity without loss of performance

264

Characterization of thin films and surface adsorbates by laser-induced thermal desorption with FTMS detection  

International Nuclear Information System (INIS)

Identifying the molecular species adsorbed on a surface is a difficult analytical problem which is important in studies of heterogeneous catalysis, corrosion, and surface contamination. Most surface analytical methods reveal very little about the molecular identity of an adsorbate. For example, Auger electron spectroscopy (AES) reveals only the elemental composition of a surface, and surface spectroscopic techniques such as electron energy loss spectroscopy and Raman spectroscopy lack the sensitivity and specificity that is needed to identify complex molecular adsorbates, particularly if there is a mixture of several species present. This talk will describe their efforts to develop the techniques of laser-induced thermal desorption (LITD) and Fourier transform mass spectrometry to characterize molecular species adsorbed on surfaces. Their approach has been to use low laser power densities to desorb neutral molecular species and post-ionization with an electron beam to produce mass spectra. Data will be presented on the characterization of the surface of a computer magnetic hard disk using AES, XPS, and LITD. AES and XPS reveal the elemental composition of the surface, and LITD is shown to be useful for identifying a variety of molecular species adsorbed on the surface

265

Removal of cyanide by eggshell as low-cost adsorbent  

Directory of Open Access Journals (Sweden)

Full Text Available Introduction: Cyanides as carbon-nitrogen radicals are very toxic compounds and highly harmful to humans and aquatic organisms. The efficacy of eggshells (ES was investigated in this research work as an adsorbent for the elimination of cyanide from polluted streams.Material and Methods: In this experimental study, the capability of ES to adsorb cyanide ions was conducted using a series of batch tests in a shaker-incubator instrument. For each batch run, 100 mL of solution containing a known initial concentration of cyanide and with the preferred level of pH was shacked. The effects of selected parameters such as pH (3-11, reaction time (5–60 min cyanide concentrations (50–150 mg/L and the adsorbent dosage (0.25–2 g/L were investigated on the removal cyanide as a target contaminate. Chemical composition ES were analyzed using a Philips model XL-30 scanning electron microscope (SEM with energy-dispersive X-ray microanalysis (EDX. The specific surface and pore size distributions of ES were measured via Brunauer-Emmett-Teller (BET isotherm and Barrett-Joyner-Halenda (BJH methods using a Micrometrics particle size analyzer. The concentration of cyanide in solution before and after treatment was determined using the titrimetric method as described in the standard methods.Results: Analysis of the ES component using the EDX technique showed that the main part of it consisted of calcium and its other components were magnesium, iron, aluminum and silicate. The experimental data showed that the maximum cyanide removal occurred at pH of 11, adsorbent dose (0.5 g/L and 40 min contact time. The kinetic evaluation indicated that the pseudo-second-order kinetic had the best fit to the experimental results predicting a chemisorption process. The equilibrium adsorption of cyanide onto ES was well represented by the Langmuir equation.Conclusion: As a result, ES as waste materials was revealed as a very efficient and low-cost adsorbent and a promising option for removing cyanide from industrial wastewaters.

Ghorban Asgari

2013-05-01

266

Removal of radioactive iodine from water using Ag{sub 2}O grafted titanate nanolamina as efficient adsorbent  

Energy Technology Data Exchange (ETDEWEB)

Highlights: ? Ag{sub 2}O nanocrystals were deposited on titanate nanolamina prepared from TiOSO{sub 4}. ? The composite is efficient adsorbent for removal of radioactive Iodine from water. ? The adsorbent exhibited a high capacity of 3.4 mmol of iodine per gram of adsorbent in 1 h. ? Ag{sub 2}O nanocrystals are firmly anchored on the surface of the titanate lamina by coherent interface. ? The adsorbent can be recovered easily for safe disposal and suitable for column adsorption-bed. -- Abstract: Emergency treatment of radioactive material leakage and safety disposal of nuclear waste is a constant concern all along with the development of radioactive materials applications. To provide a solution, titanate with large surface area (143 m{sup 2} g{sup ?1}) and a lamina morphology (the thickness of the lamina is in range of tens of nanometers) was prepared from inorganic titanium compounds by hydrothermal reactions at 433 K. Ag{sub 2}O nanocrystals (5–30 nm) were deposited onto the titanate lamina. The surface of the titanate lamina has crystallographic similarity to that of Ag{sub 2}O nanocrystals. Hence, the deposited Ag{sub 2}O nanocrystals and titanate substrate join together at these surfaces, forming a well-matched phase coherent interface between them. Such coherence between the two phases reduces the overall energy by minimizing surface energy and anchors the Ag{sub 2}O nanocrystals firmly on the external surface of the titanate structure. The composite thus obtained was applied as efficient adsorbent to remove radioactive iodine from water (one gram adsorbent can capture up to 3.4 mmol of I{sup ?} anions). The composite adsorbent can be recovered easily for safe disposal. The structure changes of the titanate lamina and the composite adsorbent were monitored by various techniques. The isotherm and kinetics of iodine adsorption, competitive adsorption and column adsorption using the adsorbent were studied to assess its iodine removal abilities. The adsorbent exhibited a capacity as high as 3.4 mmol of iodine per gram of adsorbent in 1 h. Therefore, Ag{sub 2}O deposited titanate lamina is an effective adsorbent for removing radioactive iodine from water.

Bo, Arixin; Sarina, Sarina; Zheng, Zhanfeng [School of Chemistry, Physics, Mechanical Engineering, Queensland University of Technology, GPO Box 2434, Brisbane, QLD 4001 (Australia); Yang, Dongjiang [College of Chemistry, Chemical and Environmental Engineering, Laboratory of Fiber Materials and Modern Textile, the Growing Base for State Key Laboratory, Qingdao University, Qingdao 266071 (China); Liu, Hongwei [School of Chemistry, Physics, Mechanical Engineering, Queensland University of Technology, GPO Box 2434, Brisbane, QLD 4001 (Australia); Zhu, Huaiyong, E-mail: hy.zhu@qut.edu.au [School of Chemistry, Physics, Mechanical Engineering, Queensland University of Technology, GPO Box 2434, Brisbane, QLD 4001 (Australia)

2013-02-15

267

Black molecular adsorber coatings for spaceflight applications  

Science.gov (United States)

The molecular adsorber coating is a new technology that was developed to mitigate the risk of on-orbit molecular contamination on spaceflight missions. The application of this coating would be ideal near highly sensitive, interior surfaces and instruments that are negatively impacted by outgassed molecules from materials, such as plastics, adhesives, lubricants, epoxies, and other similar compounds. This current, sprayable paint technology is comprised of inorganic white materials made from highly porous zeolite. In addition to good adhesion performance, thermal stability, and adsorptive capability, the molecular adsorber coating offers favorable thermal control characteristics. However, low reflectivity properties, which are typically offered by black thermal control coatings, are desired for some spaceflight applications. For example, black coatings are used on interior surfaces, in particular, on instrument baffles for optical stray light control. Similarly, they are also used within light paths between optical systems, such as telescopes, to absorb light. Recent efforts have been made to transform the white molecular adsorber coating into a black coating with similar adsorptive properties. This result is achieved by optimizing the current formulation with black pigments, while still maintaining its adsorption capability for outgassing control. Different binder to pigment ratios, coating thicknesses, and spray application techniques were explored to develop a black version of the molecular adsorber coating. During the development process, coating performance and adsorption characteristics were studied. The preliminary work performed on black molecular adsorber coatings thus far is very promising. Continued development and testing is necessary for its use on future contamination sensitive spaceflight missions.

Abraham, Nithin S.; Hasegawa, Mark M.; Straka, Sharon A.

2014-09-01

268

Protein purification using magnetic adsorbent particles.  

Science.gov (United States)

The application of functionalised magnetic adsorbent particles in combination with magnetic separation techniques has received considerable attention in recent years. The magnetically responsive nature of such adsorbent particles permits their selective manipulation and separation in the presence of other suspended solids. Thus, it becomes possible to magnetically separate selected target species directly out of crude biological process liquors (e.g. fermentation broths, cell disruptates, plasma, milk, whey and plant extracts) simply by binding them on magnetic adsorbents before application of a magnetic field. By using magnetic separation in this way, the several stages of sample pretreatment (especially centrifugation, filtration and membrane separation) that are normally necessary to condition an extract before its application on packed bed chromatography columns, may be eliminated. Magnetic separations are fast, gentle, scaleable, easily automated, can achieve separations that would be impossible or impractical to achieve by other techniques, and have demonstrated credibility in a wide range of disciplines, including minerals processing, wastewater treatment, molecular biology, cell sorting and clinical diagnostics. However, despite the highly attractive qualities of magnetic methods on a process scale, with the exception of wastewater treatment, few attempts to scale up magnetic operations in biotechnology have been reported thus far. The purpose of this review is to summarise the current state of development of protein separation using magnetic adsorbent particles and identify the obstacles that must be overcome if protein purification with magnetic adsorbent particles is to find its way into industrial practice. PMID:16496138

Franzreb, Matthias; Siemann-Herzberg, Martin; Hobley, Timothy J; Thomas, Owen R T

2006-05-01

269

The Dynamics and Structures of Adsorbed Surfaces  

DEFF Research Database (Denmark)

Reviews neutron scattering work performed on films of simple gas atoms and molecules adsorbed primarily on graphite surfaces. Exfoliated graphite substrates such as Grafoil were first used in this kind of measurements about five years ago and new results have been reported at an increasing pace. Elastic neutron diffraction measurements, determining the two-dimensional structural ordering of the adsorbed films, have been performed on layers of N2, Ar, H2, D2, O2, Kr, and He. Measurements on layers of larger molecules such as CD4 and ND3 have also been reported. Inelastic neutron scattering measurements, studying the dynamics of the adsorbed films are only possible in a few especially favourable cases such as 36Ar and D2 films, where the coherent phonon scattering cross-sections are very large. In other cases incoherent scattering from hydrogen can give information about e.g. the mobility of molecules such as NH3 or the internal modes of adsorbed molecules such as C4H10. Neutron scattering measurements where substrates other than graphite products are used as the adsorbents will not be reviewed here. However, the power of the technique will be demonstrated in an example of H2 physisorbed to activated alumina and in an example where hydrogen is chemisorbed to Raney nickel

Nielsen, M

1978-01-01

270

Protein purification using magnetic adsorbent particles  

DEFF Research Database (Denmark)

The application of functionalised magnetic adsorbent particles in combination with magnetic separation techniques has received considerable attention in recent years. The magnetically responsive nature of such adsorbent particles permits their selective manipulation and separation in the presence of other suspended solids. Thus, it becomes possible to magnetically separate selected target species directly out of crude biological process liquors (e.g. fermentation broths, cell disruptates, plasma, milk, whey and plant extracts) simply by binding them on magnetic adsorbents before application of a magnetic field. By using magnetic separation in this way, the several stages of sample pretreatment (especially centrifugation, filtration and membrane separation) that are normally necessary to condition an extract before its application on packed bed chromatography columns, may be eliminated. Magnetic separations are fast, gentle, scaleable, easily automated, can achieve separations that would be impossible or impractical to achieve by other techniques, and have demonstrated credibility in a wide range of disciplines, including minerals processing, wastewater treatment, molecular biology, cell sorting and clinical diagnostics. However, despite the highly attractive qualities of magnetic methods on a process scale, with the exception of wastewater treatment, few attempts to scale up magnetic operations in biotechnology have been reported thus far. The purpose of this review is to summarise the current state of development of protein separation using magnetic adsorbent particles and identify the obstacles that must be overcome if protein purification with magnetic adsorbent particles is to find its way into industrial practice.

Hobley, Timothy John

2006-01-01

271

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

International Nuclear Information System (INIS)

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

272

Surface-level mechanistic studies of adsorbate-adsorbate interactions in heterogeneous catalysis by metals  

Science.gov (United States)

Despite being considered a mature field, recent developments in experimental and theoretical techniques have greatly increased the fundamental understanding of complex surface processes in catalysis. One area of particular interest is the effect of co-adsorbed species on reactivity in heterogeneous systems. Experiments have demonstrated that co-adsorbed species, both organic and inorganic, can improve surface activity and selectivity. We begin by classifying adsorbate-adsorbate interactions that have been shown to alter the reactivity of a metal surface. We then review numerous systems where such effects have been observed using experiment or theory. Systems such as the hydrogenation of olefins with other carbonaceous adsorbates present, the chiral templating of surfaces, and the co-adsorption of alkalis, halides, and other inorganic "poisons" to improve selectivity are discussed in detail. Finally, future directions of study and outstanding questions are addressed.

Marshall, Stephen T.; Medlin, J. William

2011-05-01

273

Binary chromatographic data and estimation of adsorbent porosities. [data for system n-heptane/n-pentane  

Science.gov (United States)

Data for the system n-pentane/n-heptane on porous Chromosorb-102 adsorbent were obtained at 150, 175, and 200 C for mixtures containing zero to 100% n-pentane by weight. Prior results showing limitations on superposition of pure component data to predict multicomponent chromatograms were verified. The thermodynamic parameter MR0 was found to be a linear function of sample composition. A nonporous adsorbent failed to separate the system because of large input sample dispersions. A proposed automated data processing scheme involving magnetic tape recording of the detector signals and processing by a minicomputer was rejected because of resolution limitations of the available a/d converters. Preliminary data on porosity and pore size distributions of the adsorbents were obtained.

Meisch, A. J.

1972-01-01

274

Coatings of oxide composites  

Science.gov (United States)

During the last decade, coating processes have been extended to the reproducible deposition of composite materials on the basis of simultaneous evaporation or sputtering. Especially, ion beam sputtering from a zone target in conjunction with sophisticated optical broadband monitoring offers several advantages for the production of oxide coatings with defined mixture ratios and even Rugate filter systems with a continuous variation of the composition ratio in the depth of the layer structure. With only two materials on the zone targets, a large dynamic range of refractive index values covering the indices of the pure materials can be achieved. Recent studies on the properties of the produced oxide composites indicate a variety of interesting aspects opened by this new class of material. Among others, a blue shift of the absorption characteristic was observed for ternary oxides, and an increased LIDT, particularly for sub-picosecond coatings, has been reported. Also a number of investigations of fundamental damage mechanisms could be carried out by considering the tunable band gap energy of the coating material. In this endeavor, a group of international collaborators joined in modeling, testing and evaluating the properties of a variety of ternary oxide systems. A verification of principal material qualities was transferred to applicable multilayer coatings in a combined effort. In this paper, an overview on the achievements of these current studies is presented before the background of high power laser applications.

Jensen, Lars O.; Ristau, Detlev

2012-11-01

275

The biogeochemical cycle of the adsorbed template. II - Selective adsorption of mononucleotides on adsorbed polynucleotide templates  

Science.gov (United States)

Experimental results are presented for the verification of the specific interaction step of the 'adsorbed template' biogeochemical cycle, a simple model for a primitive prebiotic replication system. The experimental system consisted of gypsum as the mineral to which an oligonucleotide template attaches (Poly-C or Poly-U) and (5-prime)-AMP, (5-prime)-GMP, (5-prime)-CMP and (5-prime)-UMP as the interacting biomonomers. When Poly-C or Poly-U were used as adsorbed templates, (5-prime)-GMP and (5-prime)-AMP, respectively, were observed to be the most strongly adsorbed species.

Lazard, Daniel; Lahav, Noam; Orenberg, James B.

1988-01-01

276

Tailoring fly ash activated with bentonite as adsorbent for complex wastewater treatment  

International Nuclear Information System (INIS)

Highlights: ? The spent adsorbent annealed at 500 °C can be a suggestion for padding in stone blocks. ? The cations can be adsorbent by the silanol group (Si-OH) of the layers from bentonite ? Copper has a higher affinity for the active sites on adsorbent FAw + B than cadmium. ? This substrate can be recommended for simultaneous removal of heavy metals and MB. ? FAw + B is recommended for wastewater treatment resulted in the dyes finishing industry. - Abstract: Used as adsorbent, alkali fly ash represents a low cost solution for advanced wastewater treatment. The alkali treatment raises sustainability issues therefore, in this research we aim to replace alkali fly ash with washed fly ash (FAw). For improving the adsorption capacity of washed fly ash, bentonite powder (B) was added, as a natural adsorbent with a composition almost identical to the fly ash. The new adsorbent was characterized by AFM, XRD, FTIR, SEM, EDS and the surface energy was evaluated by contact angle measurements. For understanding the complex adsorption process on this mixed substrate, preliminary tests were developed on synthetic wastewaters containing a single pollutant system (heavy metal), binary (two-heavy metals) and ternary (dye and two heavy metals) systems. Experiments were done on synthetic wastewaters containing methylene blue, cadmium and copper, using FAw, B and their powder mixtures. The pseudo-second order kinetics could well model all the processes, indicating a good adprocesses, indicating a good adsorbent material which can be used for the pollutants removal from wastewater. After adsorption the substrates loaded with pollutants, annealed at 500 °C can be reused for padding in stone blocks.

277

Adsorbent cartridge for the exhaust of diazo process machines  

International Nuclear Information System (INIS)

A disposable cartridge filled with a chemical composition that acts as an adsorbent for ammonia vapor is adapted to be used in connection with a diazo process printing machine having a vacuum exhausted chamber. Exhaust from the chamber is passed through the cartridge to remove the noxious ammonia vapors and then is vented into the atmosphere. The cartridge is housed in an elongated rectangular cardboard box having three end flaps formed at each of its opposed open ends. Two opposed flaps of each set are formed with central holes and a plastic screen section adhered between these flaps to retain and allow access to the center section of the box which contains the adsorbent chemical. The center end flaps have knock-outs or tear strips that allow holes to be formed in their centers. These center end flaps cover the screens during shipment and when the cartridge is ready for use the center sections of these end flaps are knocked-out to allow the machine exhaust to be vented into and out of the cartridge

278

Adsorbents for Pressure Swing Adsorption Regeneration.  

Science.gov (United States)

This work is a continuation of the effort described in 'Evaluation of Adsorbents for Pressure Swing Adsorption' (ERDEC-CR-260). Two significant modifications to the experimental apparatus described in the previous report have been made. A back-pressure re...

D. T. Croft, D. K. Friday, J. M. Campbell

1999-01-01

279

Continuum elastic theory of adsorbate vibrational relaxation  

Science.gov (United States)

An analytical theory is presented for the damping of low-frequency adsorbate vibrations via resonant coupling to the substrate phonons. The system is treated classically, with the substrate modeled as a semi-infinite elastic continuum and the adsorbate overlayer modeled as an array of point masses connected to the surface by harmonic springs. The theory provides a simple expression for the relaxation rate in terms of fundamental parameters of the system: ?=m?¯02/Ac?cT, where m is the adsorbate mass, ?¯0 is the measured frequency, Ac is the overlayer unit-cell area, and ? and cT are the substrate mass density and transverse speed of sound, respectively. This expression is strongly coverage dependent, and predicts relaxation rates in excellent quantitative agreement with available experiments. For a half-monolayer of carbon monoxide on the copper (100) surface, the predicted damping rate of in-plane frustrated translations is 0.50×1012s-1, as compared to the experimental value of (0.43±0.07)×1012s-1. Furthermore it is shown that, for all coverages presently accessible to experiment, adsorbate motions exhibit collective effects which cannot be treated as stemming from isolated oscillators.

Lewis, Steven P.; Pykhtin, M. V.; Mele, E. J.; Rappe, Andrew M.

1998-01-01

280

Development and Testing of Molecular Adsorber Coatings  

Science.gov (United States)

The effect of on-orbit molecular contamination has the potential to degrade the performance of spaceflight hardware and diminish the lifetime of the spacecraft. For example, sensitive surfaces, such as optical surfaces, electronics, detectors, and thermal control surfaces, are vulnerable to the damaging effects of contamination from outgassed materials. The current solution to protect these surfaces is through the use of zeolite coated ceramic adsorber pucks. However, these pucks and its additional complex mounting hardware requirements result in several disadvantages, such as size, weight, and cost related concerns, that impact the spacecraft design and the integration and test schedule. As a result, a new innovative molecular adsorber coating was developed as a sprayable alternative to mitigate the risk of on-orbit molecular contamination. In this study, the formulation for molecular adsorber coatings was optimized using various binders, pigment treatment methods, binder to pigment ratios, thicknesses, and spray application techniques. The formulations that passed coating adhesion and vacuum thermal cycling tests were further tested for its adsorptive capacity. Accelerated molecular capacitance tests were performed in an innovatively designed multi-unit system containing idealized contaminant sources. This novel system significantly increased the productivity of the testing phase for the various formulations that were developed. Work performed during the development and testing phases has demonstrated successful application of molecular adsorber coatings onto metallic substrates, as well as, very promising results for the adhesion performance and the molecular capacitance of the coating. Continued testing will assist in the qualification of molecular adsorber coatings for use on future contamination sensitive spaceflight missions.

Abraham, Nithin; Hasegawa, Mark; Straka, Sharon

2012-01-01

 
 
 
 
281

Prussian blue caged in spongiform adsorbents using diatomite and carbon nanotubes for elimination of cesium  

Energy Technology Data Exchange (ETDEWEB)

Highlights: Black-Right-Pointing-Pointer Prussian blue was sealed in cavities of diatomite using carbon nanotubes. Black-Right-Pointing-Pointer The caged Prussian blue after being permanently immobilized in polyurethane spongy showed a 167 mg/g capability for absorbing cesium. Black-Right-Pointing-Pointer Cesium elimination was accomplished by simply adding the Prussian-blue based spongiform adsorbent to radioactive water. - Abstract: We developed a spongiform adsorbent that contains Prussian blue, which showed a high capacity for eliminating cesium. An in situ synthesizing approach was used to synthesize Prussian blue inside diatomite cavities. Highly dispersed carbon nanotubes (CNTs) were used to form CNT networks that coated the diatomite to seal in the Prussian blue particles. These ternary (CNT/diatomite/Prussian-blue) composites were mixed with polyurethane (PU) prepolymers to produce a quaternary (PU/CNT/diatomite/Prussian-blue), spongiform adsorbent with an in situ foaming procedure. Prussian blue was permanently immobilized in the cell walls of the spongiform matrix and preferentially adsorbed cesium with a theoretical capacity of 167 mg/g cesium. Cesium was absorbed primarily by an ion-exchange mechanism, and the absorption was accomplished by self-uptake of radioactive water by the quaternary spongiform adsorbent.

Hu, Baiyang [Graduate School of Environmental Science, Hokkaido University, Sapporo 060-0810 (Japan); Fugetsu, Bunshi, E-mail: hu@ees.hokudai.ac.jp [Graduate School of Environmental Science, Hokkaido University, Sapporo 060-0810 (Japan); Yu, Hongwen [Graduate School of Environmental Science, Hokkaido University, Sapporo 060-0810 (Japan); Abe, Yoshiteru [Kyoei Engineering Corporation, Niigata 959-1961 (Japan)

2012-05-30

282

Optimization of the preparation process of biological sludge adsorbents for application in water treatment.  

Science.gov (United States)

The objective of this study was to optimize the preparation of treatment plant wastewater sludge adsorbents for application in water treatment. The optimal adsorption capacity was obtained with adsorbents prepared by pyrolysis at 700°C for 3h. We studied the effect of binder type on the adsorbents, finding that their textural properties were not substantially affected by the addition of phenolic resins but their surface area was reduced by the presence of clayey soil. Analysis of the composition of surface groups in these materials revealed: (i) a high concentration of basic surface groups in non-activated pyrolyzed sludge, (ii) an increase in the concentration of basic surface groups after chemical activation, (iii) no modification in the concentration of carboxyl or basic groups with the addition of binding agent before the activation, and (iv) total disappearance of carbonyl groups from sample surfaces with the addition of humic acid or clayey soil as binder. All these adsorbents had a low C content. The capacity of these sludge-derived materials to adsorb methylene blue, 2,4-dichlorophenol, tetracycline, and (Cd(II)) was studied. Their adsorption capacity was considerably increased by the chemical activation but reduced by the pre-activation addition of a binding agent (humic acid, phenolic resin, and clayey soil). PMID:22472426

Gómez-Pacheco, C V; Rivera-Utrilla, J; Sánchez-Polo, M; López-Peñalver, J J

2012-05-30

283

The adsorber loop concept for the contact between seawater and adsorber granulate  

International Nuclear Information System (INIS)

The present paper deals with the so-called ''adsorber loop concept'' in which the adsorber granulate is carried along with the seawater to be processed in a loop-like configuration and is separated again from the depleted water before this is leaving the adsorption unit. This concept enables high seawater velocities thus reducing the required bed area. Theoretical considerations are presented together with experimental results from field tests. (orig.)

284

Hierarchically porous aminosilica monolith as a CO2 adsorbent.  

Science.gov (United States)

A facile strategy is successfully developed for the centimeter-scale preparation of hierarchically porous aminosilica monolith as a CO2 adsorbent just by simple processes of solvent-evaporation-induced coating, self-assembly, and concentration of tetraethyl orthosilicate sol on the surface of a polymer foam template without any adhesive composite material or hydrothermal treatment. (3-Aminopropyl) trimethoxysilane is immobilized on the surface of silica monolith via a gas-phase procedure. The silica frameworks of the monolith mimic those of the polymer foam template at the macroscale, and the frameworks are composed of the SBA-15 structure at the nanoscale. The hierarchically porous structure demonstrates improved properties over the single-mode porous component, with the macroporous framework ensuring mechanical stability and good mass transport properties, while the smaller pores provide the functionality for CO2 adsorption. PMID:25017002

Ko, Young Gun; Lee, Hyun Jeong; Kim, Jae Yong; Choi, Ung Su

2014-08-13

285

Interplay of adsorbate-adsorbate and adsorbate-substrate interactions in self-assembled molecular surface nanostructures  

DEFF Research Database (Denmark)

The adsorption of 2,6-naphthalenedicarboxylic acid (NDCA) molecules on the Ag(110), Cu(110), and Ag(111) surfaces at room temperature has been studied by means of scanning tunnelling microscopy (STM). Further supporting results were obtained using X-ray photoelectron spectroscopy (XPS) and soft X-ray absorption spectroscopy (XAS). On the Ag(110) support, which had an average terrace width of only 15 nm, the NDCA molecules form extended one-dimensional (1-D) assemblies, which are oriented perpendicular to the step edges and have lengths of several hundred nanometres. This shows that the assemblies have a large tolerance to monatomic surface steps on the Ag(110) surface. The observed behaviour is explained in terms of strong intermolecular hydrogen bonding and a strong surface-mediated directionality, assisted by a sufficient degree of molecular backbone flexibility. In contrast, the same kind of step-edge crossing is not observed when the molecules are adsorbed on the isotropic Ag(111) or more reactive Cu(110)surfaces. On Ag(111), similar 1-D assemblies are formed to those on Ag(110), but they are oriented along the step edges. On Cu(110), the carboxylic groups of NDCA are deprotonated and form covalent bonds to the surface, a situation which is also achieved on Ag(110) by annealing to 200 degrees C. These results show that the formation of particular self-assembled molecular nanostructures depends significantly on a subtle balance between the adsorbate-adsorbate and adsorbate-substrate interactions and that kinetic factors play an important role.

Schnadt, Joachim; Xu, Wei

2010-01-01

286

EMERGING TECHNOLOGY SUMMARY: DEMONSTRATION OF AMBERSORB 563 ADSORBENT TECHNOLOGY  

Science.gov (United States)

A field pilot study was conducted to demonstrate the technical feasibility and cost-effectiveness of Ambersorb® 5631 carbonaceous adsorbent for remediating groundwater contaminated with volatile organic compounds (VOCs). The Ambersorb adsorbent technology demonstration consist...

287

Preparation and tribological properties of self-lubricating TiO2/graphite composite coating on Ti6Al4V alloy  

Science.gov (United States)

One-step plasma electrolytic oxidation (PEO) process in a graphite-dispersed phosphate electrolyte was used to prepare a graphite-containing oxide composite coating on Ti6Al4V alloy. The composition and microstructure of the oxide coatings produced in the phosphate electrolytes with and without addition of graphite were analyzed by X-ray diffractometer (XRD), Raman spectroscopy, X-ray photoelectron spectroscopy (XPS) and scanning electron microscopy (SEM). The tribological properties of the uncoated Ti6Al4V alloy and oxide coatings were evaluated using a reciprocating ball-on-disk tribometer. Results showed that the graphite-containing oxide composite coating can be successfully produced on Ti6Al4V alloy in the graphite-dispersed phosphate electrolyte using PEO process. The graphite-containing oxide composite coating registered much lower friction coefficient and wear rate than the uncoated Ti6Al4V alloy and the oxide coating without graphite under dry sliding condition, exhibiting excellent self-lubricating property.

Mu, Ming; Zhou, Xinjian; Xiao, Qian; Liang, Jun; Huo, Xiaodi

2012-09-01

288

On the nature of the adsorbed hydrogen phase in microporous metal-organic frameworks at supercritical temperatures.  

Science.gov (United States)

Hydrogen adsorption measurements on different metal-organic frameworks (MOFs) over the 0-60 bar range at 50 and 77 K are presented. The results are discussed with respect to the materials' surface area and thermodynamic properties of the adsorbed phase. A nearly linear correlation between the maximum hydrogen excess amount adsorbed and the Brunauer-Emmett-Teller (BET) surface area was evidenced at both temperatures. Such a trend suggests that the adsorbed phase on the different materials is similar in nature. This interpretation is supported by measurements of the adsorbed hydrogen phase properties near saturation at 50 K. In particular it was found that the adsorbed hydrogen consistently exhibits liquid state properties despite significant structural and chemical differences between the tested adsorbents. This behavior is viewed as a consequence of molecular confinement in nanoscale pores. The variability in the trend relating the surface area and the amount of hydrogen adsorbed could be explained by differences in the adsorbed phase densities. Importantly, the latter were found to lie in the known range of bulk liquid hydrogen densities. The chemical composition and structure (e.g., pore size) were found to influence mainly how adsorption isotherms increase as a function of pressure. Finally, the absolute isotherms were calculated on the basis of measured adsorbed phase volumes, allowing for an estimation of the total amounts of hydrogen that can be stored in the microporous volumes at 50 K. These amounts were found to reach values up to 25% higher than their excess counterparts, and to correlate with the BET surface areas. The measurements and analysis in this study provide new insights on supercritical adsorption, as well as on possible limitations and optimization paths for MOFs as hydrogen storage materials. PMID:19775144

Poirier, Eric; Dailly, Anne

2009-10-20

289

Zeolites as alcohol adsorbents from aqueous solutions  

Directory of Open Access Journals (Sweden)

Full Text Available The potential usage of zeolites as adsorbents for the removal of organic molecules from water was investigated in a series of experiments with aqueous solutions of lower alcohols. This could represent a simple solution to the problem of cleaning up industrial wastewater as well as recovering valuable chemicals at relatively low costs. Adsorption isotherms of the Langmuir type were applied, and calculations showed that the amount of propanol adsorbed on silicalite corresponded to approximately 70% of the pore volume. The adsorption process is simple, and recovery of the more concentrated products is easily done by heat treatment and/or at lowered pressures. Adsorption experiments with aqueous acetone showed that silicalite had approximately the same adsorption capacity for acetone as for n-propanol. Heats of adsorption were determined calorimetrically.

Cekova Blagica

2006-01-01

290

Adsorbed natural gas storage and transportation vessels  

Energy Technology Data Exchange (ETDEWEB)

Adsorbed natural gas (ANG) storage and transportation technology recently became competitive to compressed natural gas (CNG) method due to a high energy density capability achievements. New adsorbents such as monolithic carbons and recently compressed active carbon fibers used in non-cylindrical vessels have made possible to store the same capacity of gas as CNG tanks, but at much lower pressure. New types of gas tanks thermal control systems with internal source of energy input, based on heat pipe heat exchangers, make it possible to use different sources of energy (exhausted gases, wasted engine cooling liquids, solar and other types of energy) to stimulate gas desorption at constant rate of gas delivery and constant pressure (temperature) and avoid the drop of temperature in the storage tank due to the enthalpy of desorption. (authors)

Vasiliev, L.L.; Kanonchik, L.E.; Mishkinis, D.A.; Rabetsky, M.I. [Porous Media Lab. Luikov Heat and Mass Transfer Institute (Belarus)

2000-12-01

291

Properties of adsorbates as open quantum systems  

Science.gov (United States)

We have recently developed a novel cluster-model approach to investigate adsorbate-surface systems. In our approach, a physically relevant subsystem is described as an open quantum system by considering a model cluster subject to the outgoing-wave boundary condition (OBC) at the edge of the cluster. We refer to this model as an open-boundary cluster model (OCM). Many known disadvantages of the conventional cluster-model approach, in which a model cluster is treated as an isolated system, have been remedied by introducing the OBC, whereas the local picture inherent in cluster models still remains valid. In our present research, the adsorption energy and the electron-transfer rate from adsorbates to surfaces are calculated with the OCM. Their dependences on the adsorption-distance and the Fermi energy are reasonably explained by analyzing the quasi-diabatic energy levels based on the local picture of adsorption.

Yasuike, Tomokazu; Nobusada, Katsuyuki

2008-10-01

292

Development of Eco-adsorbent Based on Solid Waste of Paper Industry to Adsorb Cadmium Ion in Water  

Directory of Open Access Journals (Sweden)

Full Text Available Eco-adsorbent prepared from paper sludge, a solid waste of paper industry, was studied to adsorb cadmium ion in water. Some parameters such as mass of the adsorbent, pH of solution, and shaking time were investigated in order to know the adsorption ability of the adsorbent. The presence of carboxyl and phenolic hydroxyl functional groups in this adsorbent were important in the process of adsorption. It was found that pH 6 to 8 of solution and 60 minutes of shaking time was a suitable condition for this adsorbent in adsorbing cadmium ion. Langmuir isotherm adsorption model was fit for this adsorbent and the adsorption capacity for Cd(II was 5.21 mg/g.

Eko Siswoyo

2013-07-01

293

Adsorbate-limited conductivity of graphene  

Digital Repository Infrastructure Vision for European Research (DRIVER)

We present a theory of electronic transport in graphene in the presence of randomly placed adsorbates. Our analysis predicts a marked asymmetry of the conductivity about the Dirac point, as well as a negative weak-localization magnetoresistivity. In the region of strong scattering, renormalization group corrections drive the system further towards insulating behavior. These results explain key features of recent experiments, and are validated by numerical transport computati...

Robinson, John P.; Schomerus, Henning; Oroszlany, Laszlo; Falko, Vladimir I.

2008-01-01

294

Kenaf Core as CO2 Adsorbent  

Directory of Open Access Journals (Sweden)

Full Text Available Kenaf is a green engineering material that has a great potential to be used as CO2 adsorbent. To enhance the capability of kenaf core as CO2 adsorbent, it should be cleaned and modified via various kinds of treatments. Prior to treatment process, the sample should be cleaned to remove all the adherent extraneous matters. In this study, kenaf core sample has been cleaned by using different types of cleaning methods such as using distilled water at room and boiling water, NaOH solution and HCl solution. This study revealed that the cleaning by using distilled water at room temperature is the most efficient way as compared to other methods. Scanning Electron Microscope (SEM carried out showed that the surface of kenaf core after cleaned by using distilled water at room temperature indicates an open cylindrical channel with similar size of honeycomb shape gaps that is beneficial to provide an active site for CO2 to be trapped or adsorbed. CO2 adsorption study conducted in Pressure Swing Adsorption (PSA column showed that kenaf core sample after cleaning by using distilled water at room temperature could adsorb CO2 up to 84.45% and relatively higher than the other methods. This study also revealed that 5 min is sufficient for adsorption to take place. Further increase in the adsorption time does not indicate any significant change to the percentage of CO2 adsorption. The future works may involve a treatment and modification of kenaf core to enhance the CO2 adsorption process.

N. Zaini

2014-01-01

295

Effective Thermal Conductivity of Adsorbent Packed Beds  

Science.gov (United States)

The effective thermal conductivity of adsorbent packed beds of granular zeolite 13X and granular silica gel A in the presence of stagnant steam or air was measured under different conditions of the adsorbent bed temperature, particle size and filler-gas pressure. The measured effective thermal conductivity showed to become smaller with decreasing particle size or decreasing pressure, but it was nearly independent of the bed temperature. When steam was the filler-gas, the rise in the thermal conductivity of the adsorbent particles due to steam adsorption led to the increase in the effective thermal conductivity of the bed, and this effect was not negligible at high steam pressure for the bed of large particle size. It was found that both the predictions of the effective thermal conductivity by the Hayashi et al.'s model and the Bauer-Schlünder model generally agreed well with the measurements, by considering the particle thermal conductivity rise due to steam adsorption. The thermal conductivity of a consolidated bed of granular zeolite 13X was also measured, and it was found to be much larger than that of the packed bed especially at lower pressure. The above prediction models underestimated the effective thermal conductivity of the consolidated bed.

Mori, Hideo; Hamamoto, Yoshinori; Yoshida, Suguru

296

Continuum Elastic Theory of Adsorbate Vibrational Relaxation  

CERN Document Server

An analytical theory is presented for the damping of low-frequency adsorbate vibrations via resonant coupling to the substrate phonons. The system is treated classically, with the substrate modeled as a semi-infinite elastic continuum and the adsorbate overlayer modeled as an array of point masses connected to the surface by harmonic springs. The theory provides a simple expression for the relaxation rate in terms of fundamental parameters of the system: $\\gamma = m\\bar{\\omega}_0^2/A_c \\rho c_T$, where $m$ is the adsorbate mass, $\\bar{\\omega}_0$ is the measured frequency, $A_c$ is the overlayer unit-cell area, and $\\rho$ and $c_T$ are the substrate mass density and transverse speed of sound, respectively. This expression is strongly coverage dependent, and predicts relaxation rates in excellent quantitative agreement with available experiments. For a half-monolayer of carbon monoxide on the copper (100) surface, the predicted damping rate of in-plane frustrated translations is $0.50\\times 10^{12}$~s$^{-1}$, a...

Lewis, S P; Mele, E J; Rappe, A M; Lewis, Steven P.; Rappe, Andrew M.

1997-01-01

297

Activity of Aflatoxins Adsorbents in Poultry Feed  

Directory of Open Access Journals (Sweden)

Full Text Available The flatoxins produced by Aspergillus flavus and A. parasiticus have been detected in various poultry feed resources. They have a negative affect on the performance of birds as the presence of Aflatoxins significantly inhibit the growth and productive performance of birds and even mortality in certain cases. They have also negative effect on the immune response of bird. The toxin binders e.g. Myco-Ad, Sorbatox and Mycofix-Plus have been claimed to adsorb or inactivate Aflatoxins in the body and thus reduce the toxicity effect of Aflatoxins. These toxin binders have also certain reports to adsorb various nutrients along with toxins resulting in their specific deficiency symptoms. The present study was designed to observe the effects of three different toxin binders in two phases on the performance of cross chicken (FAY x RIR in terms of weekly weight gain, feed consumption, feed conversion ratio and mortality. The results indicated that any product did not affect the performance of birds during five week of age. It showed that Myco-Ad, Sorbatox and Mycofix-Plus had no affect on the nutrient adsorption in poultry feed. During second phase the results indicated that all the three products significantly adsorbed Aflatoxins, which was reflected in terms of improved weight gain, feed conversion ratio and mortality of the birds.

Yasmin Mussaddeq

2000-01-01

298

Breakdown products formed due to oxidation of adsorbed phenol by electrochemical regeneration of a graphite adsorbent  

International Nuclear Information System (INIS)

Phenol was studied as a model pollutant for treatment by adsorption and electrochemical regeneration using a graphite intercalation compound (GIC) adsorbent in an air agitated sequential batch reactor. The mechanism of electrochemical regeneration is important in determining the fate of the adsorbed species. The effect of a range of operating parameters including current density, pH, electrolyte addition, and the initial concentration of phenol on the formation of the intermediate oxidation products was investigated. The main breakdown products detected were benzoquinone and chlorinated organics (chloride was present as an electrolyte in the cathode compartment), with small amounts of hydroquinone, catechol, and carboxylic acids detected under some conditions. The effect of current density on the formation of breakdown products during electrochemical regeneration was found to be similar to effects reported in the literature for the electrochemical oxidation of a phenol solution. In contrast to acidic pH, very low concentrations of benzoquinone were observed during electrochemical regeneration of GIC adsorbent under neutral and alkaline conditions. The results obtained with high initial phenol concentration (100 mg L?1) suggested that breakdown products could be formed either by oxidation of adsorbed phenol or indirect oxidation of phenol in solution. Comparison of experiments carried out with different amounts of adsorbed and dissolved phenol suggested that the intermediate oxidation products obtained was formed largely due to indirect electrochemical oxidation of organics in solution. In particular, it was found that the chlorinated organics detected in solution were generated from the indirect oxidation of phenol in solution

299

Removal of adsorbent particles od copper ions by Jet flotation  

International Nuclear Information System (INIS)

The present study shows the results obtained on the removal of copper ions from synthetic effluents by using the adsorbent particles flotation technique (APF) in a Jet flotation cell (Jameson type). In a typical experimental run, a mineral with high quartz content was used as adsorbent particles in the adsorption and flotation experiments, to determine optimal pH conditions, adsorbent particles concentration; flotation reagents dosage and air/effluent flow ratio for applying in the Jet cell to maximize the efficiency of copper ions adsorptions and the removal of particles adsorbents containing the absorbed copper ions. The results indicate the at pH>7 and at adsorbent particles concentration of 2 kg.m-3, 99% of copper ions is adsorbed and, when the air/effluent flow ratio applied in the Jet cell is 0,2, 98% of absorbent particles containing the adsorbed copper ions is removed. (Author) 39 refs.

300

Synthesis and properties of carbon adsorbents from brown coals  

Energy Technology Data Exchange (ETDEWEB)

The optimal conditions for synthesis of high-porosity carbon adsorbents with a developed surface by thermal pyrolysis of brown coals in the absence of oxygen were determined. The physicochemical properties of the resultant adsorbents were studied, as well as adsorption of carbon and sulfur oxides and ammonia by them. The strength and nature of the integration between the carbon adsorbents and the adsorbates depend both on the properties of the adsorbates themselves and on the parameters of the porous structure, as well as on the acid-base characteristics of the adsorbents. Sorption of CO{sub 2} in micropores is due to dispersion forces. Adsorption of SO{sub 2} proceeds via both physical adsorption and chemical interaction with basic surface oxides of the adsorbents. The sites of the specific adsorption of NH{sub 3} are acidic oxygen complexes.

Anurov, S.A. [Mendeleev University of Chemical Engineering, Moscow (Russian Federation)

1999-03-01

 
 
 
 
301

Ion exchangers as adsorbents for removing metals from aquatic media.  

Science.gov (United States)

A polyaniline-based composite cation-exchange material was synthesized by way of sol-gel method and studied to explore its analytical and environmental applications. It was characterized by using instrumental analyses [Fourier transform infrared (spectrometer), X-ray, thermogravimetric analysis/differential thermal analysis, standard electron microscopy, and transmission electron microscopy]. Physicochemical studies, such as ion-exchange capacity, pH titrations, and chemical stability, along with effect of eluent concentration and elution, were also performed to exploit the ion-exchange capabilities. pH titration studies showed that the material presents monofunctional strong cation-exchange behavior. This nanocomposite material is semicrystalline in nature and exhibits improved thermal and chemical stability. The partition coefficient studies of different metal ions in the material were performed in demineralised water and different surfactant media, and it was found to be selective for Pb(II) and Hg(II) ions. To exploit the usefulness of the material as an adsorbent, some important quantitative binary separations of metal ions were performed on polyaniline Zr(IV) molybdophosphate columns. This composite cation exchanger can be applied for the treatment of polluted water to remove heavy metals. PMID:24292693

Khan, Meraj A; Bushra, Rani; Ahmad, Anees; Nabi, Syed A; Khan, Dilwar A; Akhtar, Arshia

2014-02-01

302

Adsorption equilibria and kinetics for phenol and cresol onto polymeric adsorbents: Effects of adsorbents/adsorbates structure and interface  

International Nuclear Information System (INIS)

Phenol and cresol (o-, m-, and p-) were selected as the adsorbates with different dipole moment (cresol > phenol, methyl being electron-drawing group) and solubility (phenol > cresol, methyl being hydrophobic group). Macropore polymers (NDA-1800 and XAD-4), hypercrosslinked polymers (NDA-100), and chemically modified adsorbents (NDA-150 and NDA-99), were comparatively used to investigate the adsorption properties including equilibria, thermodynamics and kinetics. First, all of the results about equilibria show that the adsorption data fit well to the Freundlich model. The adsorption capacity of NDA-99 and NDA-150 especially for phenol is larger in a certain extent than other three types of polymers. The hydrophobic interaction from large specific surface was mainly occurred, while the polar groups containing oxygen and amine markedly enhance the adsorption process via hydrogen interaction. Furthermore, the adsorption amount for NDA-99 and XAD-4 decrease linearly with the solubility of solutes tested. Then, the negative values of enthalpy demonstrate the predominantly exothermic and physical solid-extraction processes. Finally, the relatively more rapid adsorption process could be found onto NDA-150 than NDA-99, with the reason of the double larger pore size of the former. In conclusion, solubility of solute, together with surface area, pore size and modified groups, extremely exerts influences to the adsorption performances

303

Spectroscopy and dynamics of orientationally structured adsorbates  

CERN Document Server

This book provides a detailed and rigorous presentation of the spectroscopy and dynamics of orientationally structured adsorbates. It is intended largely for specialists and graduate students in solid state theory and surface physics. To make the book readable also for beginners in surface science, a lucid style is used and a wealth of references on orientational surface structures and vibrational excitations in them is offered. The book is supplemented with two indices (alphabetical listing of subjects and authors, as well as cross-references) which will enable the reader to easily access the

Rozenbaum, V M

2002-01-01

304

Theory for melting anomalies in adsorbate systems  

International Nuclear Information System (INIS)

Melting anomalies, observed in a variety of adsorbate systems such as N2, Ar or CH4 on TiO2 and H2O absorbed in coal, Al2O3, zeolite, or porous glass, are shown to be manifestations of the melting characteristics of small molecular clusters. The theoretical results show not only that melting is a continuous phenomenon for small aggregates, but that for clusters consisting of ten to twenty molecules, melting may commence at temperatures considerably lower than the bulk melting point. Comparison between the theory and experimental data yields excellent agreement. (orig.)

305

Stability constants for silicate adsorbed to ferrihydrite  

DEFF Research Database (Denmark)

Intrinsic surface acidity constants (K(a1)intr, K(a2)intr) and surface complexation constant for adsorption of orthosilicate onto synthetic ferrihydrite (K(Si) for the complex = FeOSi(OH)3) have been determined from acid/base titrations in 0.001-0.1 m NaClO4 electrolytes and silicate adsorption experiments in 0.01 m NaNO3 electrolyte (pH 3-6). The surface equilibrium constants were calculated according to the two-layer model by Dzombak & Morel (1990). Near equilibrium between protons/hydroxyls in solution and the ferrihydrite surface was obtained within minutes while equilibration with silicate required days-weeks, both reactions probably being diffusion controlled. Applying the values for specific surface area and site densities for ferrihydrite used by Dzombak & Morel (1990) (600 m2 g-1, 3.4 mumole m-2) the constants pK(al)intr 6.93 +/- 0.12, pK(a2)intr = 8.72 +/- 0.17 and log K(Si) = 3.62 were calculated by using the FITEQL optimization routine. Use of the specific surface area actually measured (269 m2 g-1) gave a poorer fit of the experimental data. Due to the slow adsorption of silicate and hence long shaking times, changes in the surface characteristics of the ferrihydrite seem to take place, probably a decrease in the concentration of surface sites. Adsorption isotherms calculated using the derived equilibrium constants showed that approximately twice the amount of silicate was adsorbed at pH 5 compared with pH 3. Infrared spectroscopy of silica adsorbed to ferrihydrite showed Si-O stretching absorption maxima in the range 940-960 cm- 1. The shift of the absorption maximum to higher wavenumbers with increasing amount of silicate adsorbed is probably due to an increase in the frequency of Si-O-Si bonds between orthosilicate adsorbed at adjacent sites. Small amounts of goethite were identified in the adsorption products.

Hansen, Hans Christian Bruun; Wetche, T.P.

1994-01-01

306

Heat capacity measurements of atoms and molecules adsorbed on evaporated metal films  

International Nuclear Information System (INIS)

Investigations of the properties of absorbed monolayers have received great experimental and theoretical attention recently, both because of the importance of surface processes in practical applications such as catalysis, and the importance of such systems to the understanding of the fundamentals of thermodynamics in two dimensions. We have adapted the composite bolometer technology to the construction of microcalorimeters. For these calorimeters, the adsorption substrate is an evaporated film deposited on one surface of an optically polished sapphire wafer. This approach has allowed us to make the first measurements of the heat capacity of submonolayer films of 4He adsorbed on metallic films. In contrast to measurements of 4He adsorbed on all other insulating substrates, we have shown that 4He on silver films occupies a two-dimensional gas phase over a broad range of coverages and temperatures. Our apparatus has been used to study the heat capacity of Indium flakes. CO multilayers, 4He adsorbed on sapphire and on Ag films and H2 adsorbed on Ag films. The results are compared with appropriate theories. 68 refs., 19 figs

307

Tailoring fly ash activated with bentonite as adsorbent for complex wastewater treatment  

Science.gov (United States)

Used as adsorbent, alkali fly ash represents a low cost solution for advanced wastewater treatment. The alkali treatment raises sustainability issues therefore, in this research we aim to replace alkali fly ash with washed fly ash (FAw). For improving the adsorption capacity of washed fly ash, bentonite powder (B) was added, as a natural adsorbent with a composition almost identical to the fly ash. The new adsorbent was characterized by AFM, XRD, FTIR, SEM, EDS and the surface energy was evaluated by contact angle measurements. For understanding the complex adsorption process on this mixed substrate, preliminary tests were developed on synthetic wastewaters containing a single pollutant system (heavy metal), binary (two-heavy metals) and ternary (dye and two heavy metals) systems. Experiments were done on synthetic wastewaters containing methylene blue, cadmium and copper, using FAw, B and their powder mixtures. The pseudo-second order kinetics could well model all the processes, indicating a good adsorbent material which can be used for the pollutants removal from wastewater. After adsorption the substrates loaded with pollutants, annealed at 500 °C can be reused for padding in stone blocks.

Visa, Maria

2012-12-01

308

Adsorption characteristics of water vapor on honeycomb adsorbents  

Science.gov (United States)

Recovery of tritium released into working areas in nuclear fusion plants is a key issue of safety. A large volume of air from tritium fuel cycle or vacuum vessel should be processed by air cleanup system (ACS). In ACS, tritium gas is oxidized by catalysts, and then tritiated water vapor is collected by adsorbents. This method can remove tritium effectively, whereas high throughput of air causes high-pressure drop in catalyst and adsorbent beds. In this study, the applicability of honeycomb-type adsorbents, which offers a useful advantage in terms of their low-pressure drop, to ACS was examined, in comparison with conventional pebble-type adsorbent. Honeycomb-type adsorbent causes far less pressure drop than pebble-type adsorbent beds. Adsorption capacity of water vapor on a honeycomb-type adsorbent is slightly lower than that on a pebble-type adsorbent, while adsorption rate of water vapor on honeycomb-type adsorbent is much higher than that of pebble-type adsorbent.

Wajima, Takaaki; Munakata, Kenzo; Takeishi, Toshiharu; Hara, Keisuke; Wada, Kouhei; Katekari, Kenichi; Inoue, Keita; Shinozaki, Yohei; Mochizuki, Kazuhiro; Tanaka, Masahiro; Uda, Tatsuhiko

2011-10-01

309

Synthesis of Nanocomposite Adsorbent on the Base of Polypropylene Fabric with Copper Ferrocyanide Grains  

Directory of Open Access Journals (Sweden)

Full Text Available Composite adsorbents based on polypropylene fibers with chemically bound nanopartices of copper ferrocyanide were synthesized by two-stage experiment: radiation-induced graft polymerization of acrylic acid onto non-woven polypropylene fabric followed by in-situ formation of copper ferrocyanize nanoparticles and their stabilization on the fabric surface within the grafted layer. Scanning electron microscope investigations revealed a homogeneous compact layer of copper ferrocynide nanosized aggregates (65-70 nm. The synthesized composite material was stable in the base solutions (pH ? 10.5 and exhibited high efficiency for cesium adsorption.

Bondar I.V.

2012-08-01

310

Hexavalent chromium removal using indigenously developed adsorbents  

International Nuclear Information System (INIS)

Present study is based on the usage of natural waste material i.e. two types of tree leaves (ficus Religiosa and Pongamia Pinnata) for the adsorption of Cr(VI). Hexavalent chromium removal efficiency of developed sorbents is determined experimentally. Effect of different variables like shaking time, shaking speed, initial metal ion concentration, adsorbent dose, pH, and of temperature was studied. Both adsorbents showed almost complete chromium removal at pH value of 2.0 and adsorption is shown to be endothermic in nature for pongamia pinnata leaves. Optimum values obtained in this study are, pH 2.0, shaking speed 200 rpm, shaking time 45 minutes, temperature of 50 degree C. Adsorption capacities obtained at optimum conditions are 17.5 and 15.7 mg/g for ficus religiosa and Pongamia Pinnata leaves respectively. Adsorption data follow Langmuir model. Predominant adsorption phenomenon on leaves seems to be surface adsorption but other binding mechanism like ion exchange may also be a contributing factor. (author)

311

Photodecomposition of chloromethanes adsorbed on silica surfaces  

Science.gov (United States)

Irradiation of CCl4, CFCl3, and CF2Cl2 in the presence of C2H6 in vessels containing silica sand or fused quartz tubing results in the formation of chlorine-containing products. The formation of these compounds occurs at wavelengths extending up to approximately 400 nm, that is, at wavelengths well beyond the absorption threshold of the chloromethanes in the gas phase. It is suggested that CCl4 adsorbed on silica surfaces photodissociates to yield CCl3 and CCl2 species. The poor material balance obtained in these experiments indicates that several of the chlorine-containing fragments are strongly adsorbed on the surface. At a CCl4 pressure of 13 Pa (0.1 torr), photolysis with 366 nm light in the presence of sand results in the decomposition of one molecule for every 10,000 photons striking the surface. Under otherwise identical conditions, the photon-induced breadkdown of CFCl3 and CF2Cl2 is respectively only 10% or 3% as efficient.

Ausloos, P.; Rebbert, R. E.; Glasgow, L.

1977-01-01

312

Design of spherical carbon adsorbent for extracorporeal detoxification.  

Science.gov (United States)

A special carbon adsorbent (CA), designed for use in extracorporeal detoxification by hemoperfusion, was produced from a spherical synthetic polymer by our own technolique and tested at a preclinical level. Comparison of mechanical properties, sorption and biocompatibility between CA and medical hemosorbents was made. The carbon adsorbent is hard, has a smooth surface, shows good sorption properties and has acceptable biocompatibility. These features qualify the carbon adsorbent for use in clinical hemoperfusion without any additional membrane coating. PMID:25273162

Rosinski, S; Sentek, J; Lewinska, D

1993-01-01

313

TESTING OF CARBONACEOUS ADSORBENTS FOR REMOVAL OF POLLUTANTS FROM WATER  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Testing of carbonaceous adsorbents for removal of pollutants from water. Relevant direction for improving of quality of potable water is application of active carbons at various stages of water treatments. This work includes complex research dealing with testing of a broad spectrum of carbonaceous adsorbents for removal of hydrogen sulfide and nitrite ions from water. The role of the surface functional groups of carbonaceous adsorbents, their acid-basic properties, and the influence of the ty...

RAISA NASTAS; MARINA TCACI; TATIANA GOREACIOC; Rusu, V.; Lupascu, T.

2012-01-01

314

Chemical State of Adsorbed Sulfur on Pt Nanoparticles  

Energy Technology Data Exchange (ETDEWEB)

The chemical state of adsorbed sulfur (S) on a Pt surface was identified and investigated by a combination of detailed electrochemical (EC) measurements, in situ surface enhanced Raman scattering (SERS) and ab initio density functional theory (DFT) calculations. The SERS data of the adsorbed S coupled with the DFT calculations provide the first convincing evidence showing that the adsorbed sulfur is in a sulfide (S2?) state.

Park, In-Su; Xu, Bolian; Atienza, Dianne O.; Hofstead-Duffy, Augusta M.; Allison, Thomas C.; Tong, Yu ye J.

2011-03-14

315

Fundamental characteristics of synthetic adsorbents intended for industrial chromatographic separations.  

Science.gov (United States)

With the aim of obtaining comprehensive information on the selection of synthetic adsorbents for industrial applications, effect of pore and chemical structure of industrial-grade synthetic adsorbents on adsorption capacity of several pharmaceutical compounds was investigated. For relatively low molecular mass compounds, such as cephalexin, berberine chloride and tetracycline hydrochloride, surface area per unit volume of polystyrenic adsorbents dominated the equilibrium adsorption capacity. On the contrary, effect of pore size of the polystyrenic adsorbents on the equilibrium adsorption capacity was observed for relatively high molecular mass compounds, such as rifampicin, Vitamin B12 and insulin. Polystyrenic adsorbent with high surface area and small pore size showed small adsorption capacity for relatively high molecular mass compounds, whereas polystyrenic adsorbent with relatively small surface area but with large pore size showed large adsorption capacity. Effect of chemical structure on the equilibrium adsorption capacity of several pharmaceutical compounds was also studied among polystyrenic, modified polystyrenic and polymethacrylic adsorbents. The modified polystyrenic adsorbent showed larger adsorption capacity for all compounds tested in this study due to enhanced hydrophobicity. The polymethacrylic adsorbent possessed high adsorption capacity for rifampicin and insulin, but it showed lower adsorption capacity for the other compounds studied. This result may be attributed to hydrogen bonding playing major role for the adsorption of compounds on polymethacrylic adsorbent. Furthermore, column adsorption experiments were operated to estimate the effect of pore characteristics of the polystyrenic adsorbents on dynamic adsorption behavior, and it is found that both surface area and pore size of the polystyrenic adsorbents significantly affect the dynamic adsorption capacity as well as flow rate. PMID:15139411

Adachi, Tadashi; Isobe, Eiji

2004-05-14

316

Carbonaceous adsorbent regeneration and halocarbon displacement by hydrocarbon gases  

Science.gov (United States)

This invention describes a process for regeneration of halocarbon bearing carbonaceous adsorbents through which a carbonaceous adsorbent is contacted with hydrocarbon gases, preferably propane, butane and pentane at near room temperatures and at atmospheric pressure. As the hydrocarbon gases come in contact with the adsorbent, the hydrocarbons displace the halocarbons by physical adsorption. As a result of using this process, the halocarbon concentration and the hydrocarbon eluant is increased thereby allowing for an easier recovery of pure halocarbons. By using the process of this invention, carbonaceous adsorbents can be regenerated by an inexpensive process which also allows for subsequent re-use of the recovered halocarbons.

Senum, Gunnar I. (Patchogue, NY); Dietz, Russell N. (Patchogue, NY)

1994-01-01

317

Methylphenols removal from water by low-cost adsorbents.  

Science.gov (United States)

A comparative study on the adsorption of methylphenols on adsorbents prepared from several industrial wastes has been carried out. The results show that extent of adsorption on carbonaceous adsorbent prepared from fertilizer industry waste has been found to be 37.3, 40.5, 65.9, and 88.5 mg/g for 2-methylphenol, 4-methylphenol, 2,4-dimethylphenol, and 2,4,6-trimethylphenol, rspectively. As compared to carbonaceous adsorbent, the other three adsorbents viz. blast furnace sludge, dust, and slag adsorb methylphenols to a much smaller extent. This has been accounted for due to the carbonaceous adsorbent having a larger porosity and consequently higher surface area. The adsorption of phenols on this carbonaceous adsorbent as a function of contact time, concentration, and temperature has been studied by the batch method. The adsorption has been found to be endothermic and data conform to the Langmuir equation. The analysis of data indicates that adsorption is a first-order process and pore diffusion-controlled. The efficiency of the carbonaceous adsorbent was assessed by comparing the results with those on a standard activated charcoal sample. It was found that the carbonaceous adsorbent is about 45% as efficient as standard activated charcoal and can therefore be employed for the removal of methylphenols from wastewaters. PMID:16802460

Jain, A K; Suhas; Bhatnagar, A

2002-07-01

318

WGS-Adsorbent Reaction Studies at Laboratory Scale  

International Nuclear Information System (INIS)

This document reports the most significant results obtained during the experimental work performed under task WGS adsorbent experimental studies within CAPHIGAS project (National Research Plan 2008-2011, ref: ENE2009-08002). The behavior of the binary adsorbent-catalyst system which will be used in the hybrid system is described in this document. Main results reported here were used during the design and development of the hybrid system adsorbent catalyst- membrane proposed in the CAPHIGAS project. The influence of main operating parameters and the optimized volume ratio adsorbent-catalyst are also presented in this report. (Author)

319

Role of structure and glycosylation of adsorbed protein films in biolubrication.  

Science.gov (United States)

Water forms the basis of lubrication in the human body, but is unable to provide sufficient lubrication without additives. The importance of biolubrication becomes evident upon aging and disease, particularly under conditions that affect secretion or composition of body fluids. Insufficient biolubrication, may impede proper speech, mastication and swallowing, underlie excessive friction and wear of articulating cartilage surfaces in hips and knees, cause vaginal dryness, and result in dry, irritated eyes. Currently, our understanding of biolubrication is insufficient to design effective therapeutics to restore biolubrication. Aim of this study was to establish the role of structure and glycosylation of adsorbed protein films in biolubrication, taking the oral cavity as a model and making use of its dynamics with daily perturbations due to different glandular secretions, speech, drinking and eating, and tooth brushing. Using different surface analytical techniques (a quartz crystal microbalance with dissipation monitoring, colloidal probe atomic force microscopy, contact angle measurements and X-ray photo-electron spectroscopy), we demonstrated that adsorbed salivary conditioning films in vitro are more lubricious when their hydrophilicity and degree of glycosylation increase, meanwhile decreasing their structural softness. High-molecular-weight, glycosylated proteins adsorbing in loops and trains, are described as necessary scaffolds impeding removal of water during loading of articulating surfaces. Comparing in vitro and in vivo water contact angles measured intra-orally, these findings were extrapolated to the in vivo situation. Accordingly, lubricating properties of teeth, as perceived in 20 volunteers comprising of equal numbers of male and female subjects, could be related with structural softness and glycosylation of adsorbed protein films on tooth surfaces. Summarizing, biolubrication is due to a combination of structure and glycosylation of adsorbed protein films, providing an important clue to design effective therapeutics to restore biolubrication in patients with insufficient biolubrication. PMID:22916138

Veeregowda, Deepak H; Busscher, Henk J; Vissink, Arjan; Jager, Derk-Jan; Sharma, Prashant K; van der Mei, Henny C

2012-01-01

320

Adsorption of dyes and phenol from water on resin adsorbents: effect of adsorbate size and pore size distribution.  

Science.gov (United States)

Batch adsorption runs of two commercial reactive dyes (methylene blue and reactive orange X-GN) and phenol from water onto two resin adsorbents (Amberlite XAD-4, a macroreticular adsorbent and ZCH-101, a hyper-cross-linked adsorbent) were carried out in the present study. Effect of adsorbate size and pore structure of the resin adsorbents on adsorption was discussed and Langmuir and Freundlich models were tested for the relevant adsorption isotherms. In the kinetic section concentration-time profiles were obtained to further elucidate the effect of adsorbate size and porous structure on adsorption mechanism. A pseudo-second-order model was proved to give a satisfactory description of the related kinetic results. Two-stage kinetic curve of methylene blue onto ZCH-101 was observed at a specific experimental condition and modeled schematically according to its specific pore size distribution. Furthermore, other kinetic experiments were performed at different ambient temperature to validate the proposed schematic model. PMID:16704907

Zhang, Xiao; Li, Aimin; Jiang, Zhenmao; Zhang, Quanxing

2006-09-21

 
 
 
 
321

NOx Removal and Effect of Adsorbate-Adsorbate Interactions  

DEFF Research Database (Denmark)

Heterogeneous catalysis is immensely important to modern and future society. It forms the foundation of chemical industry, supplying essential chemicals and commodities for transport, food production, and pharmaceuticals, and is also a cornerstone in current and future energy platforms. If the long-standing dream of an environmentally sustainable energy sector is to be fulfilled, heterogeneous catalysts aiding production, storage, and use of energy from sustainable sources, e.g. sunlight, wind, and biomass, are expected to be essential. New catalysts improving the efficiency of existing chemical processes, such as ammonia synthesis and sulphur removal in refining, may also contribute to improving future society at large. However, developing the catalysts of tomorrow presents a wealth of scientific challenges. Understanding surface science has always been essential for development and improvement of industrial chemical processes, nano-science and nano-technology, in general any process where a solid surface interacts with any surrounding liquid or gas-phase species. Computational approaches play an increasingly important role in modern surface science, and density functional theory (DFT) in particular. Indeed, several recent developments in our understanding of important aspects of heterogeneous catalysis derive from electronic structure calculations based on DFT. However, there are still many challenges and lots of scope for improvement in the density functional approach to surface science. To mention a few, to improve the accuracy of electronic structure calculations, accuracy of the physical model, completeness of kinetic models for chemical reactions, figuring out the exact state of catalysts under reaction conditions, and also reducing the complexity of our physical models. In this thesis I have analyzed these challenges systematically and have developed some new methods and models to counter those challenges and obtain some general understanding of the catalytic process. I have developed an adsorbate-adsorbate interaction model to include the coverage dependency of the adsorption energy in kinetic models to obtain more accurate catalytic rates than with the commonly used non-interacting mean field model. I then applied the proposed adsorbate-adsorbate interaction model to three important catalytic reactions, the direct NO decomposition, CO methanation, and steam reforming of methane, and analyzed the effect of adsorbate-adsorbate interactions on their catalytic rates. An alloy screening method has also been developed to screen for the industrially most promising alloy catalysts for any catalytic reaction. I have also studied the structure sensitivity of the rates of catalytic direct NO decomposition on different low-index metal surfaces. Furthermore, I have used DFT calculated adsorption and transition state energies coupled with a microkinetic model to study two industrially important catalytic reactions, NH3 oxidation and selective catalytic reduction of NOx, to obtain the catalytic trends and understand the reaction mechanisms.

Khan, Tuhin Suvra

2013-01-01

322

Adsorbed and Grafted Polymers at Equilibrium  

CERN Document Server

This chapter deals with various aspects related to the adsorption of longchain-like macromolecules (polymers) onto solid surfaces. Physical aspects ofthe adsorption mechanism are elaborated mainly at thermodynamical equilibrium.The basic features needed in modeling of this adsorption are discussed. Wefirst discuss the adsorption of a single and long polymer chain to the surface.The surface interaction is modeled by a potential well with a long-rangedattractive tail. A simple mean-field theory description is presented and theconcept of polymer "blobs" is used to describe the conformation of the chain atthe surface. The thickness of the adsorbed layer depends on several polymer andsurface parameters. Fluctuation corrections to mean-field theory are alsodiscussed. We then review adsorption as well as depletion processes in themany-chain case. Profiles, changes in the surface tension and polymer surfaceexcess are calculated within mean-field theory. Corrections due to fluctuationsin good solvent are taken into ac...

Andelman, D; Andelman, David; Netz, Roland R.

2000-01-01

323

Ion exchange/adsorbent pilot plant  

International Nuclear Information System (INIS)

A decontamination of greater than 99% of the actinides and fission products contained in radioactive waste water can be obtained using ion exchange resins. A system for achieving this result is described in this paper. This ion exchange pilot-plant design is the culmination of five years of study of the decontamination of radioactive waste streams by ion exchange resins and other adsorbents at Mound. In order to maintain maximum flexibility of treatments, this pilot-plant design is a conceptual design with specific flows, resins, and column specifications, but with many optional features and no rigid equipment specifications. This flexibility allows the system to be amenable to almost any radioactive waste stream. Very specific designs can be constructed from this conceptual design for the treatment of any specific waste stream. Operating and capital costs are also discussed. 1 figure, 5 tables

324

Limited Range Fractality of Randomly Adsorbed Rods  

CERN Document Server

Multiple resolution analysis of two dimensional structures composed of randomly adsorbed penetrable rods, for densities below the percolation threshold, has been carried out using box-counting functions. It is found that at relevant resolutions, for box-sizes, $r$, between cutoffs given by the average rod length $$ and the average inter-rod distance $r_1$, these systems exhibit apparent fractal behavior. It is shown that unlike the case of randomly distributed isotropic objects, the upper cutoff $r_1$ is not only a function of the coverage but also depends on the excluded volume, averaged over the orientational distribution. Moreover, the apparent fractal dimension also depends on the orientational distributions of the rods and decreases as it becomes more anisotropic. For box sizes smaller than $$ the box counting function is determined by the internal structure of the rods, whether simple or itself fractal. Two examples are considered - one of regular rods of one dimensional structure and rods which are tri...

Lidar, D A; Avnir, D; Lidar, Daniel A.; Biham, Ofer; Avnir, David

1997-01-01

325

Canyon solvent cleaning with solid adsorbents  

International Nuclear Information System (INIS)

The HM Process at the Savannah River Plant (SRP) uses 7.5% tributyl phosphate in n-paraffin as an extraction solvent. During use, the solvent is altered due to hydrolysis and radiolysis, forming materials that influence product losses, product decontamination, and separation efficiencies. Laboratory studies to improve online solvent cleaning have shown that carbonate washing, although removing residual solvent activity, does not remove binding ligands that hold fission products in the solvent. Treatment of solvent with a solid adsorbent removes binding ligands and significantly improves recycle solvent performance. Both laboratory work defining a full-scale adsorption process and the use of the process to clean HM Process first cycle solvent are presented

326

Utilization of Waste Eggshells as Humidity Adsorbent  

Directory of Open Access Journals (Sweden)

Full Text Available The chicken and duck eggshell powders were prepared and heated at 1300C for 4 h. The samples were analyzed by X-Ray Diffraction (XRD. It was found that Calcium Carbonate (CaCO3 from chicken and duck eggshells completely transformed into Calcium Oxide (CaO. Then the samples were placed in a box installed with a hygro-thermometer for humidity adsorption test in the range of 20-75% RH at 25C. Hydration rate for duck and chicken eggshells were 0.0625% RH min-1 (within 880 min and 0.0482% RH min-1 (within 1140 min respectively. The results show that CaO from the duck eggshells is a better adsorbent than that of chicken eggshells. Furthermore, after humidity adsorption, CaO obtained from both eggshells were partly transformed into portlandite (Ca(OH2 was confirmed by the Rietveld refinement method and Scanning Electron Microscope (SEM.

S. Limsuwan

2011-01-01

327

The condensation of water on adsorbed viruses.  

Science.gov (United States)

The wetting and dewetting behavior of biological nanostructures and to a greater degree single molecules is not well-known even though their contact with water is the basis for all biology. Here, we show that environmental electron microscopy (EM) can be applied as a means of imaging the condensation of water onto viruses. We captured the formation of submicrometer water droplets and filaments on single viral particles by environmental EM and by environmental transmission EM. The condensate structures are compatible with capillary condensation between adsorbed virus particles and with known droplet shapes on patterned surfaces. Our results confirm that such droplets exist down to condensation/evaporation cycle as expected from their stability in air and water. Moreover we developed procedures that overcome problems of beam damage and of resolving structures with a low atomic number. PMID:24160759

Alonso, José María; Tatti, Francesco; Chuvilin, Andrey; Mam, Keriya; Ondarçuhu, Thierry; Bittner, Alexander M

2013-11-26

328

Film morphology and orientation of amino silicone adsorbed onto cellulose substrate  

International Nuclear Information System (INIS)

A series of amino silicones with different amino values were synthesized and adsorbed onto surfaces of cotton fibers and cellulose substrates. The film morphology, hydrophobic properties and surface composition of the silicones are investigated and characterized by field emission scanning electron microscope (FESEM), atomic force microscope (AFM), contact angle measurement, X-ray photoelectron spectroscopy (XPS) and attenuated total reflectance infrared (ATR-IR). The results of the experiments indicate that the amino silicone can form a hydrophobic film on both cotton fibers and cellulose substrates and reduce the surface roughness significantly. Furthermore, the roughness becomes smaller with an increase in the amino value. All these results suggest that the orientation of amino silicone molecule is with the amino functional groups of amino silicone molecule adsorbed onto the cellulose interface while the main polymer chains and the hydrophobic Si-CH3 groups extend toward the air.

329

Structural characterization and thermal analysis of 4 A and 5 A zeolite adsorbents  

International Nuclear Information System (INIS)

Adsorption processes are widely used in the industries, both for purification and for bulk separation. The discovery and commercialization of synthetic zeolites as adsorption provide a major stimulus to the development of adsorption as a separation process. The primary requirement for development of an adsorption separation process using zeolite is the structural characterization of the material. The most important analysis include the evaluation of pore volume, pore size distribution, surface area and density. This paper describes commercial zeolitic adsorbents, its structure and the methods applied to its characterization. They work also an experimental study where different analytical techniques were used to determine the physical properties, chemical composition and crystalline structure for type 4A zeolitic adsorbents. (author)

330

Milestone Report - Complete New Adsorbent Materials for Marine Testing to Demonstrate 4.5 g-U/kg Adsorbent  

Energy Technology Data Exchange (ETDEWEB)

This report describes work on the successful completion of Milestone M2FT-14OR03100115 (8/20/2014) entitled, “Complete new adsorbent materials for marine testing to demonstrate 4.5 g-U/kg adsorbent”. This effort is part of the Seawater Uranium Recovery Program, sponsored by the U.S. Department of Energy, Office of Nuclear Energy, and involved the development of new adsorbent materials at the Oak Ridge National Laboratory (ORNL) and marine testing at the Pacific Northwest National Laboratory (PNNL). ORNL has recently developed two new families of fiber adsorbents that have demonstrated uranium adsorption capacities greater than 4.5 g-U/kg adsorbent after marine testing at PNNL. One adsorbent was synthesized by radiation-induced graft polymerization of itaconic acid and acrylonitrile onto high surface area polyethylene fibers followed by amidoximation and base conditioning. This fiber showed a capacity of 4.6 g-U/kg adsorbent in marine testing at PNNL. The second adsorbent was prepared by atom-transfer radical polymerization of t-butyl acrylate and acrylonitrile onto halide-functionalized round fibers followed by amidoximation and base hydrolysis. This fiber demonstrated uranium adsorption capacity of 5.4 g-U/kg adsorbent in marine testing at PNNL.

Janke, Christopher James [ORNL; Das, Sadananda [ORNL; Oyola, Yatsandra [ORNL; Mayes, Richard T. [ORNL; Saito, Tomonori [ORNL; Brown, Suree [ORNL; Gill, Gary [PNNL; Kuo, Li-Jung [PNNL; Wood, Jordana [PNNL

2014-08-01

331

Thermodynamic study of fatty acids adsorption on different adsorbents  

International Nuclear Information System (INIS)

This work has as objective the study about the adsorption behavior of fatty acids (acetic, propionic, and butyric) on activated carbon and on modified and unmodified montmorillonite clays as a function of temperature and initial concentration of the adsorbate, through adsorption isotherms and their thermodynamic parameters (?G, ?H, and ?S). The activated carbon presented a higher adsorption capacity due to its relatively large surface area, compared to others adsorbents. The polar characteristic of fatty acids decreased with the increase in the length of non-polar hydrocarbon chain, improving the affinity between the activated carbon (non-polar adsorbent) and the acids. The adsorption capacity of modified montmorillonite (polar adsorbent) was favored due to the presence of the organic cation among its layers, which make the surface more hydrophobic and organophilic when compared to the unmodified montmorillonite surface. The amount of fatty acids adsorbed in the adsorbents surface increased with the concentration, at constant temperature, and decreased with the increase of temperature, at constant concentration. The amount of fatty acids adsorbed in the three adsorbents was related to the surface area and polarity of the adsorbent, concentration and solubility of the adsorbate and temperature of the solution. The negative values of ?G and ?H showed that the adsorption on activated carbon and on modified and unmodified montmorillonite clays was a spontaneous and allonite clays was a spontaneous and an exothermic process. The decrease in the values of ?G, with the increase of temperature, demonstrated that the adsorption was benefited by the high temperature and the positive values of ?S showed that the fatty acids molecules were in a more randomic condition in the adsorbed state than in solution. The experimental results obtained at the temperatures of (298, 303, 313, and 323) K showed that experimental data were well represented by the Langmuir and Freundlich isotherms models

332

Resilience of gas-phase anharmonicity in the vibrational response of adsorbed carbon monoxide and breakdown under electrical conditions  

CERN Document Server

In surface catalysis, the adsorption of carbon monoxide on transition-metal electrodes represents the prototype of strong chemisorption. Notwithstanding significant changes in the molecular orbitals of adsorbed CO, spectroscopic experiments highlight a close correlation between the adsorbate stretching frequency and equilibrium bond length for a wide range of adsorption geometries and substrate compositions. In this work, we study the origins of this correlation, commonly known as Badger's rule, by deconvoluting and examining contributions from the adsorption environment to the intramolecular potential using first-principles calculations. Noting that intramolecular anharmonicity is preserved upon CO chemisorption, we show that Badger's rule for adsorbed CO can be expressed solely in terms of the tabulated Herzberg spectroscopic constants of isolated CO. Moreover, although it had been previously established using finite-cluster models that Badger's rule is not affected by electrical conditions, we find here th...

Dabo, Ismaila

2012-01-01

333

SORPTION PROPERTIES OF MODEL COMPOUNDS ON C18 ADSORBENTS  

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The bonded silica adsorbent Bondapak-C18 was evaluated for removing organic matter from secondary sewage effluents and from solutions of pure organic compounds. The adsorbent is hydrophobic and its behavior with water samples may be erratic unless first wet with a solvent. Howeve...

334

Cell for studying electron-adsorbed gas interactions  

International Nuclear Information System (INIS)

The geometry and the technology of a cell used for investigations on electron-adsorbed gas interactions are described. The resonance frequencies of the surface ions which are created by the electron impact on the adsorbed gas are predicted by simplified calculations. The experimental data relative to carbon monoxide and neon are in good agreement with these predictions. (authors)

335

Adsorbents based on carbon microfibers and carbon nanofibers for the removal of phenol and lead from water.  

Science.gov (United States)

This paper describes the production, characteristics, and efficacy of carbon microfibers and carbon nanofibers for the removal of phenol and Pb(2+) from water by adsorption. The first adsorbent produced in the current investigation contained the ammonia (NH(3)) functionalized micron-sized activated carbon fibers (ACF). Alternatively, the second adsorbent consisted of a multiscale web of ACF/CNF, which was prepared by growing carbon nanofibers (CNFs) on activated ACFs via catalytic chemical vapor deposition (CVD) and sonication, which was conducted to remove catalytic particles from the CNF tips and open the pores of the CNFs. The two adsorbents prepared in the present study, ACF and ACF/CNF, were characterized by several analytical techniques, including SEM-EDX and FT-IR. Moreover, the chemical composition, BET surface area, and pore-size distribution of the materials were determined. The hierarchal web of carbon microfibers and nanofibers displayed a greater adsorption capacity for Pb(2+) than ACF. Interestingly, the adsorption capacity of ammonia (NH(3)) functionalized ACFs for phenol was somewhat larger than that of the multiscale ACF/CNF web. Difference in the adsorption capacity of the adsorbents was attributed to differences in the size of the solutes and their reactivity towards ACF and ACF/CNF. The results indicated that ACF-based materials were efficient adsorbents for the removal of inorganic and organic solutes from wastewater. PMID:21507421

Chakraborty, Anindita; Deva, Dinesh; Sharma, Ashutosh; Verma, Nishith

2011-07-01

336

Removal of Acid Orange 7 from aqueous solution using magnetic graphene/chitosan: a promising nano-adsorbent.  

Science.gov (United States)

Magnetic graphene/chitosan (MGCh) nanocomposite was fabricated through a facile chemical route and its application as a new adsorbent for Acid Orange 7 (AO7) removal was also investigated. After synthesis, the full characterization with various techniques (FTIR, XRD, VSM, and SEM) was achieved revealing many possible interactions/forces of dye-composite system. The results showed that, benefiting from the surface property of graphene oxide, the abundant amino and hydroxyl functional groups of chitosan, and from the magnetic property of Fe3O4, the adsorbent possesses quite a good and versatile adsorption capacity to the dye under investigation, and can be easily and rapidly extracted from water by magnetic attraction. The maximum absorption capacity was reached at initial pH 3 and 120min contact time. The batch adsorption experiments showed that the adsorption of the AO7 is considerably dependent on pH of milieu, amount of adsorbent, and contact time. The adsorption kinetics and isotherms were investigated to indicate that the kinetic and equilibrium adsorption were well-described by pseudo-first order kinetic and Langmuir isotherm model, respectively. The adsorption behavior suggested that the adsorbent surface was homogeneous in nature. The study suggests that the MGCh is a promising nano adsorbent for removal of anionic azo dyes from aqueous solution. PMID:24813679

Sheshmani, Shabnam; Ashori, Alireza; Hasanzadeh, Saeed

2014-07-01

337

Carbon nanotube adsorbed on hydrogenated Si(0 0 1) surfaces  

International Nuclear Information System (INIS)

The structural and electronic properties of a metallic single-walled carbon nanotube (CNT), adsorbed on hydrogenated Si(0 0 1) surfaces, have been investigated by first-principles calculations. We find that the electronic properties of the adsorbed CNT can be ruled by the H concentration along the CNT-H/Si(0 0 1) contact region. (i) On the fully hydrogenated Si(0 0 1), the CNT is physisorbed, preserving almost unchanged its metallic character. (ii) Removing half the H atoms along the adsorption site, we find an enhancement on the metallicity of the adsorbed CNT. (iii) When all the H atoms along the adsorption site are removed, the adsorbed CNT becomes semiconducting, exhibiting an energy gap. These results suggest that metallic CNTs adsorbed on H/Si(0 0 1) could be transformed into metal-semiconductor junctions by grading the H concentration along the CNT-surface interface

338

Carbon nanotube adsorbed on hydrogenated Si(0 0 1) surfaces  

Energy Technology Data Exchange (ETDEWEB)

The structural and electronic properties of a metallic single-walled carbon nanotube (CNT), adsorbed on hydrogenated Si(0 0 1) surfaces, have been investigated by first-principles calculations. We find that the electronic properties of the adsorbed CNT can be ruled by the H concentration along the CNT-H/Si(0 0 1) contact region. (i) On the fully hydrogenated Si(0 0 1), the CNT is physisorbed, preserving almost unchanged its metallic character. (ii) Removing half the H atoms along the adsorption site, we find an enhancement on the metallicity of the adsorbed CNT. (iii) When all the H atoms along the adsorption site are removed, the adsorbed CNT becomes semiconducting, exhibiting an energy gap. These results suggest that metallic CNTs adsorbed on H/Si(0 0 1) could be transformed into metal-semiconductor junctions by grading the H concentration along the CNT-surface interface.

Miwa, R.H. [Faculdade de Fisica, Universidade Federal de Uberlandia, C.P. 593, 38400-902 Uberlandia, MG (Brazil)]. E-mail: hiroki@infis.ufu.br; Orellana, W. [Instituto de Fisica, Universidade de Sao Paulo, C.P. 66318, 05315-970 Sao Paulo, SP (Brazil); Fazzio, A. [Instituto de Fisica, Universidade de Sao Paulo, C.P. 66318, 05315-970 Sao Paulo, SP (Brazil)

2005-05-15

339

Sequestering nickel (ii) ions from aqueous solutions using various adsorbents  

International Nuclear Information System (INIS)

Adsorption process has proven to be one of the best water treatment technologies around the world and activated carbon is undoubtedly considered as a universal adsorbent for the removal of different types of pollutants from water. However, widespread use of commercial activated carbon is sometimes restricted due to its high cost. Attempts have been made to develop inexpensive adsorbents utilizing numerous agro-industrial and municipal waste materials. Use of agricultural waste materials as low-cost adsorbents is attractive because it reduces the cost of waste disposal, thereby leading to environmental protection. In this review, agricultural, synthetic and other adsorbents used for adsorbing nickel (II) ion from aqueous solutions are reported. Different ways to improve their efficiencies are also discussed. (author)

340

Relationship of the critical parameters of adsorbed gases with the initial heats of adsorption on carbon adsorbents  

Energy Technology Data Exchange (ETDEWEB)

The initial heats of adsorption on microporous carbon adsorbents (Saran and S charcoals) are proportional to the critical parameters of the adsorbates. Doubling of the initial heat of adsorption in the slit micropore of S-band charcoal relative to the initial heat of absorption on the basis graphite face was established experimentally.

Berezin, G.I.

1986-06-20

 
 
 
 
341

Neutron reflectivity study of adsorbed diblock copolymers  

International Nuclear Information System (INIS)

This paper summarizes our cumulative work on neutron reflectivity studies of polystyrene-poly(vinyl-2-pyridine) (PS-PVP) and polystyrenepolyethylene oxide (PS-PEO) adsorbed at a quartz-solvent interface. Deuterated toluene was chosen as the solvent since it is a good solvent for PS and a poor one for either of the other two blocks. In this case, the polystyrene dangles into the solvent while the other block acts as an anchor. The neutron reflectivity studies reveal that the form of the polymer density profile normal to the substrate may be varied from an extended ''brush'' to a condensed ''mushroom'' conformation by manipulating the ratio of the molecular weights of the two blocks. In addition, we present new data on the PS-PEO system in a poor solvent, deuterated cyclohexane, under conditions of shear flow in Poiseuille geometry. We find that when the PS-PEO diblock is absorbed from cyclohexane and is allowed to relax, the PS chain takes on a ''mushroom'' conformation. However, when the shear is applied, the layer shear thickens due to the PS chains extended to nearly twice their original lengths

342

Surface characterization of Ag/Titania adsorbents  

International Nuclear Information System (INIS)

The Ag/Titania adsorbent for selective removal of the desulfurization-refractive polycyclic aromatic sulfur heterocycles (PASHs) from liquid hydrocarbon fuels was prepared, its total and the Ag specific surface area were determined and the surface reaction sites in the sorbent that may be active in the adsorptive selective desulfurization were characterized by several spectroscopic and surface science techniques. The sorbent contains Ag, Ti, O and spurious C on its surface, as by the XPS measurements. Silver is present as an oxide, as judged by the XPS Auger parameter (AP). The complementary electron spin resonance (ESR) spectroscopy confirms that the majority of Ag is present in the diamagnetic Ag1+ form, with the minor concentration (?0.1% of total Ag) present as Ag2+. The findings by XPS and ESR are confirmed by the XRD, UV-vis spectroscopy and thermodynamic considerations. The supported Ag is highly dispersed on the surface of the titania support, with the particle size of ?30-60 A depending on Ag content, with an Ag specific surface area of ?7-14 m2/g, vs. the total surface area of ?114-58 m2/g.

343

Imaging the dynamics of individually adsorbed molecules  

Science.gov (United States)

Although noise is observed in many experiments, it is rarely used as a source of information. However, valuable information can be extracted from noisy signals. The motion of particles on a surface induced, for example, by thermal activation or by the interaction with the tip of a scanning tunnelling microscope may lead to fluctuations or switching of the tunnelling current. The analysis of these processes gives insight into dynamics on a single atomic or molecular level. Unfortunately, scanning tunnelling microscopy (STM) is not a useful tool to study dynamics in detail, as it is an intrinsically slow technique. Here, we show that this problem can be solved by providing a full real-time characterization of random telegraph noise in the current signal. The hopping rate, the noise amplitude and the relative occupation of the involved states are measured as a function of the tunnelling parameters, providing spatially resolved maps. In contrast to standard STM, our technique gives access to transiently populated states revealing an electron-driven hindered rotation between the equilibrium and two metastable positions of an individually adsorbed molecule. The new approach yields a complete characterization of copper phthalocyanine molecules on Cu(111), ranging from dynamical processes on surfaces to the underlying electronic structure on the single-molecule level.

Schaffert, Johannes; Cottin, Maren C.; Sonntag, Andreas; Karacuban, Hatice; Bobisch, Christian A.; Lorente, Nicolás; Gauyacq, Jean-Pierre; Möller, Rolf

2013-03-01

344

DBPs removal in GAC filter-adsorber.  

Science.gov (United States)

A rapid sand filter and granular activated carbon filter-adsorber (GAC FA) were compared in terms of dissolved organic carbon (DOC) and disinfection by-products (DBPs) removal. A water treatment plant (WTP) that had a high ammonia concentration and DOC in raw water, which, in turn, led to a high concentration of DBPs because of a high dose of pre-chlorination, was investigated. To remove DBPs and DOC simultaneously, a conventional rapid sand filter had been retrofitted to a GAC FA at the Buyeo WTP in Korea. The overall removal efficiency of DBPs and DOC was higher in the GAC FA than in the sand filter, as expected. Breakthrough of trihalomethanes (THMs) was noticed after 3 months of GAC FA operation, and then removal of THMs was minimal (90%) in HAA(5) removal efficiency was again observed, which could be attributed to biodegradation. At the early stage of GAC FA operation, HAA(5) removal was largely due to physical adsorption, but later on biodegradation appeared to prevail. Biodegradation of HAA(5) was significantly influenced by water temperature. Similar turbidity removal was noticed in both filters, while better manganese removal was confirmed in the sand filter rather than in the GAC FA. PMID:17706265

Kim, Jinkeun; Kang, Byeongsoo

2008-01-01

345

Bowl inversion of surface-adsorbed sumanene.  

Science.gov (United States)

Bowl-shaped ?-conjugated compounds offer the possibility to study curvature-dependent host-guest interactions and chemical reactivity in ideal model systems. For surface-adsorbed ? bowls, however, only conformations with the bowl opening pointing away from the surface have been observed so far. Here we show for sumanene on Ag(111) that both bowl-up and bowl-down conformations can be stabilized. Analysis of the molecular layer as a function of coverage reveals an unprecedented structural phase transition involving a bowl inversion of one-third of the molecules. On the basis of scanning tunneling microscopy (STM) and complementary atomistic simulations, we develop a model that describes the observed phase transition in terms of a subtle interplay between inversion-dependent adsorption energies and intermolecular interactions. In addition, we explore the coexisting bowl-up and -down conformations with respect to host-guest binding of methane. STM reveals a clear energetic preference for methane binding to the concave face of sumanene. PMID:25181621

Jaafar, Rached; Pignedoli, Carlo A; Bussi, Giovanni; Aït-Mansour, Kamel; Groening, Oliver; Amaya, Toru; Hirao, Toshikazu; Fasel, Roman; Ruffieux, Pascal

2014-10-01

346

How adsorbate alignment leads to selective reaction.  

Science.gov (United States)

There has been much interest in the effect of adsorbate alignment in a surface reaction. Here we show its significance for an electron-induced reaction occurring along preferred axes of the asymmetric Cu(110) surface, characterized by directional copper rows. By scanning tunneling microscopy (STM), we found that the heterocyclic aromatic reagent, physisorbed meta-iodopyridine, lay with its carbon-iodine either along the rows of Cu(110), "A", or perpendicular, "P". Electron-induced dissociative attachment with the C-I bond initially along "A" gave a chemisorbed I atom and chemisorbed vertical pyridyl, singly surface-bound, whereas that with C-I along "P" gave a chemisorbed I atom and a horizontal pyridyl, doubly bound. An impulsive two-state model, involving a short-lived antibonding state of C-I, accounted for the different product surface binding in terms of closer Cu···Cu atomic spacing along "A" accommodating only one binding site of the pyridyl ring recoiling from I and wider spacing along "P" accommodating simultaneously both binding sites, N-Cu and C-Cu, in the meta-position on the recoiling pyridyl ring. STM studies combined with dynamical modeling can be seen as a way to improve understanding of the role of surface alignment in determining reactive outcomes in induced reaction at asymmetric crystalline surfaces. PMID:25102432

Cheng, Fang; Ji, Wei; Leung, Lydie; Ning, Zhanyu; Polanyi, John C; Wang, Chen-Guang

2014-08-26

347

Carbon dioxide pressure swing adsorption process using modified alumina adsorbents  

Science.gov (United States)

A pressure swing adsorption process for absorbing CO.sub.2 from a gaseous mixture containing CO.sub.2 comprising introducing the gaseous mixture at a first pressure into a reactor containing a modified alumina adsorbent maintained at a temperature ranging from 100.degree. C. and 500.degree. C. to adsorb CO.sub.2 to provide a CO.sub.2 laden alumina adsorbent and a CO.sub.2 depleted gaseous mixture and contacting the CO.sub.2 laden adsorbent with a weakly adsorbing purge fluid at a second pressure which is lower than the first pressure to desorb CO.sub.2 from the CO.sub.2 laden alumina adsorbent. The modified alumina adsorbent which is formed by depositing a solution having a pH of 3.0 or more onto alumina and heating the alumina to a temperature ranging from 100.degree. C. and 600.degree. C., is not degraded by high concentrations of water under process operating conditions.

Gaffney, Thomas Richard (Allentown, PA); Golden, Timothy Christopher (Allentown, PA); Mayorga, Steven Gerard (Allentown, PA); Brzozowski, Jeffrey Richard (Bethlehem, PA); Taylor, Fred William (Allentown, PA)

1999-01-01

348

Adsorption of sodium dodecylsulfate on modified carbon adsorbents  

Science.gov (United States)

The adsorption of anionic surfactants on carbon adsorbents modified with water-soluble derivatives of natural polymers, cellulose and chitin, is considered with sodium dodecylsulfate taken as an example. It is shown that such modification leads to changes in the adsorption structural characteristics and the particle size distribution of carbon-water suspensions of the original adsorbent, and to the emergence of new functional groups on its surface that are able to interact selectively with adsorbate molecules. It is assumed that adsorption of anionic surfactant on carbon adsorbents under equilibrium conditions proceeds via stepwise filling of the carbon's porous structure: we first observe volume filling of micropores according to their sizes, and then the formation of a surfactant's monolayer in mesopores and on the outer surface of the adsorbate. It is established by thermal analysis that the thermal stability of carbon adsorbents is enhanced through the preferential localization of anionic surfactants in micropores. The filling of mesopores and the outer carbon surface by surfactant molecules leads to a regular decrease in thermal stability and an increase in the adsorbent surface's hydrophilicity.

Ivanets, M. G.; Savitskaya, T. A.; Nevar, T. N.; Grinshpan, D. D.

2012-11-01

349

Photoemission studies of clean and adsorbate covered metal surfaces using synchrotron and uv radiation sources  

International Nuclear Information System (INIS)

Photoemission energy distribution experiments on clean metal and adsorbate-covered surfaces were performed under ultrahigh vacuum conditions by using x-ray and ultraviolet photon sources in the laboratory as well as continuously-tunable, highly polarized synchrotron radiation obtainable at the Stanford Synchrotron Radiation Laboratory (SSRL). Studies focused on two general areas: cross-section modulation in the photoemission process was studied as a function of photon energy and orbital composition. Sharp decreases in intensity of the valence bands of several transition metals (i.e., Ag, Au, and Pt) are attributed to the radial nodes in the respective wave functions. Adsorbate photoemission studies of CO adsorbed on platinum single crystals have demonstrated a very high spectral sensitivity to the 4sigma and (1? + 5sigma) peaks of CO at photon energies of 150 eV. Angle-resolved photoemission allowed determination of the orientation of CO chemisorbed on a Pt (111) or Ni(111) surface. Prelinimary results at high photon energies (approximately 150 eV) indicated scattering from the substrate which could yield chemisorption site geometries

350

The impact of surface-adsorbed phosphorus on phytoplankton Redfield stoichiometry.  

Science.gov (United States)

The Redfield ratio of 106 carbon:16 nitrogen:1 phosphorus in marine phytoplankton is one of the foundations of ocean biogeochemistry, with applications in algal physiology, palaeoclimatology and global climate change. However, this ratio varies substantially in response to changes in algal nutrient status and taxonomic affiliation. Here we report that Redfield ratios are also strongly affected by partitioning into surface-adsorbed and intracellular phosphorus pools. The C:N:surface-adsorbed P (80-105 C:15-18 N:1 P) and total (71-80 C:13-14 N:1 P) ratios in natural populations and cultures of Trichodesmium were close to Redfield values and not significantly different from each other. In contrast, intracellular ratios consistently exceeded the Redfield ratio (316-434 C:59-83 N:1 intracellular P). These high intracellular ratios were associated with reduced N2 fixation rates, suggestive of phosphorus deficiency. Other algal species also have substantial surface-adsorbed phosphorus pools, suggesting that our Trichodesmium results are generally applicable to all phytoplankton. Measurements of the distinct phytoplankton phosphorus pools may be required to assess nutrient limitation accurately from elemental composition. Deviations from Redfield stoichiometry may be attributable to surface adsorption of phosphorus rather than to biological processes, and this scavenging could affect the interpretation of marine nutrient inventories and ecosystem models. PMID:15602560

Sañudo-Wilhelmy, Sergio A; Tovar-Sanchez, Antonio; Fu, Fei-Xue; Capone, Douglas G; Carpenter, Edward J; Hutchins, David A

2004-12-16

351

Effects of adsorbents in dairy cow diet on milk quality and cheese-making properties  

Directory of Open Access Journals (Sweden)

Full Text Available The use of adsorbents (clinoptilolite+sepiolite in the diet of cows was evaluated in two trials. A total of 52 Italian Friesian cows were assigned to one of two dietary treatments, control and adsorbent (CON vs. ADS. Individual and bulk milk samples were collected. On individual data, no significant difference was found between treatments in milk yield, milk fat, protein, and lactose concentrations, milk protein yield, pH, and titratable acidity, both in summer and spring. In spring only, there was a trend (P = 0.07 for a higher milk fat yield and a lower somatic cell number in ADS than in CON group. In summer only, milk clotting time was higher in ADS than in CON group (P < 0.05. On bulk milk, no significant differences in components and technological features were found between the CON and ADS groups. The bulk milk contents in total and soluble Ca were 1100 vs. 1108 mg/kg and 378 vs. 369 mg/kg for CON and ADS respectively, proving to be unaffected by treatment and suggesting a lack of interference by ADS on milk Ca availability for cheese-making process.We concluded that, for a period of 12 weeks, the addition of 1% on DM of the diet for lactating cows of non-nutritional adsorbents does not negatively affect milk yield, milk composition, and cheese-making features.

G. Pirlo

2010-04-01

352

Polyethyleneimine Incorporated Metal-Organic Frameworks Adsorbent for Highly Selective CO2 Capture  

Science.gov (United States)

A series of polyethyleneimine (PEI) incorporated MIL-101 adsorbents with different PEI loadings were reported for the first time in the present work. Although the surface area and pore volume of MIL-101 decreased significantly after loading PEI, all the resulting composites exhibited dramatically enhanced CO2 adsorption capacity at low pressures. At 100 wt% PEI loading, the CO2 adsorption capacity at 0.15 bar reached a very competitive value of 4.2 mmol g-1 at 25°C, and 3.4 mmol g-1 at 50°C. More importantly, the resulting adsorbents displayed rapid adsorption kinetics and ultrahigh selectivity for CO2 over N2 in the designed flue gas with 0.15 bar CO2 and 0.75 bar N2. The CO2 over N2 selectivity was up to 770 at 25°C, and 1200 at 50°C. We believe that the PEI based metal-organic frameworks is an attractive adsorbent for CO2 capture.

Lin, Yichao; Yan, Qiuju; Kong, Chunlong; Chen, Liang

2013-05-01

353

The morphology, proliferation rate, and population doubling time factor of adipose-derived mesenchymal stem cells cultured on to non-aqueous SiO2, TiO2, and hybrid sol-gel-derived oxide coatings.  

Science.gov (United States)

In recent years, much attention has been paid to the development of tissue engineering and regenerative medicine, especially when stem cells of various sources are concerned. In addition to the interest in mesenchymal stem cells isolated from bone marrow, recently more consideration has been given to stem cells isolated from adipose tissue (AdMSCs), due to their less invasive method of collection as well as their ease of isolation and culture. However, the development of regenerative medicine requires both the application of biocompatible material and the stem cells to accelerate the regeneration. In this study, we investigated the morphology, proliferation rate index (PRi), and population doubling time factor of adipose-derived mesenchymal stem cells cultured on non-aqueous sol-gel-derived SiO2, TiO2, and SiO2/TiO2 oxide coatings. The results indicated an increase in PRi of AdMSCs when cultured on to titanium dioxide, suggesting its high attractiveness for AdMSCs. In addition, the proper morphology and the shortest doubling time of AdMSCs were observed when cultured on titanium dioxide coating. PMID:24408867

Marycz, Krzysztof; Krzak-Ro?, Justyna; Donesz-Sikorska, Anna; ?mieszek, Agnieszka

2014-11-01

354

EFFECT OF KOH ON MICRO-ARC OXIDATION COATINGS OF 2A12 ALUMINUM ALLOYS IN CH3COONa-Na2WO4 ELECTROLYTE  

Science.gov (United States)

The ceramic coatings were prepared on 2A12 alloy by micro-arc oxidation in CH3COONa-Na2WO4 electrolyte system with different concentration of KOH added. The effects of KOH in this electrolyte on micromorphology, phase compositions, adhesion and corrosion resistance of the coatings were investigated by scanning electron microscope (SEM), X-ray diffraction (XRD), scratch test and electrochemistry workstation. The results show that KOH has a significant influence on the surface morphology, which can make the surface smoother. The adhesion of the coating becomes stronger with the increase of KOH in the electrolyte. The corrosion resistance of the coated specimen increases a lot compared with that of the substrate. And the lowest corrosion current density (Icorr) of the coating prepared in the electrolyte with KOH is about three orders of magnitude lower than that of the substrate.

Lin, Zhao Qing; Yu, Hui Jun; He, Si Yu; He, Yi Ning; Chen, Chuan Zhong

2014-02-01

355

The use of low-cost adsorbents for wastewater purification in mining industries.  

Science.gov (United States)

Recently, great attention has been paid to the environmental problems in mining industry. At present there are different ways of mineral processing, as well as various methods of wastewater treatment, most of them are expensive. Work is ongoing to find low-cost treatments. In this article, low-cost adsorbents, potentially useful for wastewater treatment on mining and metallurgical plants, are reviewed; their characteristics, advantages, and disadvantages of their application are compared. Also adsorption of different metals and radioactive compounds from acidic environment similar to composition of mining and metallurgical wastewaters is considered. PMID:23436121

Iakovleva, Evgenia; Sillanpää, Mika

2013-11-01

356

Polyethyleneimine Incorporated Metal-Organic Frameworks Adsorbent for Highly Selective CO2 Capture  

Digital Repository Infrastructure Vision for European Research (DRIVER)

A series of polyethyleneimine (PEI) incorporated MIL-101 adsorbents with different PEI loadings were reported for the first time in the present work. Although the surface area and pore volume of MIL-101 decreased significantly after loading PEI, all the resulting composites exhibited dramatically enhanced CO2 adsorption capacity at low pressures. At 100 wt% PEI loading, the CO2 adsorption capacity at 0.15 bar reached a very competitive value of 4.2?mmol g?1 at 25°C, and 3.4?mmol g?1 ...

Lin, Yichao; Yan, Qiuju; Kong, Chunlong; Chen, Liang

2013-01-01

357

Surface enhanced Raman scattering of pyrazole adsorbed on silver colloids  

Science.gov (United States)

SERS spectra of pyrazole adsorbed on silver hydrosol at different pH values and on silver colloidal substrate deposited on filters were obtained and interpreted on the basis of the existence of three forms in equilibrium, cationic, neutral and anionic. SERS data indicate that the neutral molecule is preferentially adsorbed in acidic environment, pyrazolide anion is instead favoured over all the other pH values. Addition of chloride anions induces the formation of reaction products when pyrazole is adsorbed on silver hydrosols, while this effect is missing on dry silver substrate.

Muniz-Miranda, Maurizio; Neto, Natale; Sbrana, Giuseppe

1999-05-01

358

Application of a new adsorbent for fluoride removal from aqueous solutions  

International Nuclear Information System (INIS)

Highlights: • A new adsorbent has been prepared. • The adsorbent is non-toxic and easy to synthesize. • HBO1 has displayed best capacity for the removal of fluoride. • Unlike most adsorbents, HBO1 is suitable for the removal of fluoride from water. • The process of removal has been optimized. -- Abstract: Hydrous bismuth oxides (HBOs) have been investigated as a possible adsorbent for fluoride removal from water. Apart from bismuth trioxide (Bi2O3) compound, three additional HBOs, named as HBO1, HBO2, and HBO3 were synthesized in the laboratory and examined for their relative potentials for fluoride removal from aqueous solutions. HBO1 was observed to have highest fluoride removal at 10 mg/L initial concentration in aqueous environment. Among competitive anions, sulfate and chloride affect the fluoride removal by HBO1 more adversely than bicarbonate. Characterization of HBOs using X-ray diffraction (XRD) pattern analyses indicated crystalline structures, and the broad chemical composition of materials showed successive increase of Bi(OH)3 from HBO1 to HBO3, with decrease of BiOCl in the same order. Fourier Transform Infrared (FTIR) spectroscopy analyses indicated presence of Bi-O bond and successively increasing number of peaks corresponding to OH ion from HBO1 to HBO3. Scanning Electron Microscopic (SEM) images of HBOs show rough and porous structure of the materials. Presence of higher proportion of chloride compound in HBO1 with respect to others appears to be the factor responsible for its better performance in fluoride removal from aqueous solutions

359

Modulation Effects of K2ZrF6 Additive on Microstructure and Heat Resistance of Micro-arc Oxide Coatings Fabricated on LY12 Aluminum Alloy  

Directory of Open Access Journals (Sweden)

Full Text Available Zr(OH4 particle can be formed and negatively charged in alkaline solution with K2ZrF6 addition. Based on this mechanism, Zr-containing ceramic coatings were fabricated on LY12 aluminum alloy by microarc oxidation (MAO using K2ZrF6 as a special additive in Na2SiO3-KOH base electrolyte. The modulation effects of K2ZrF6 addition on micro-microstructure, element distribution and phase composition were analyzed by SEM, EDS and XRD, respectively. Heat resistance of MAO coatings formed on LY12 aluminum alloy in different electrolyte was investigated. The results show that the K2ZrF6 addition can increase the micro-arc oxidation rate and significantly alter the structure of MAO coatings. Both the top surface and inner surface of MAO coatings fabricated in Zr-containing electrolyte become relatively smooth. Compared with the coating formed in Zr-free electrolyte, a large amount of Zr element is found in the coating formed in electrolyte with K2ZrF6 addition. Two main phases, ?-Al2O3 and ?-Al2O3, are contained in Zr-free coating. In contrast, more amorphous phase is found in Zr-containing coating with reduced amount of crystalline alumina. Experimental results also demonstrate that Zr-containing coating exhibits higher heat resistance.

ZHANG Xin-Meng, CHEN Dong-Fang, GONG Chun-Zhi , YANG Shi-Qin, TIAN Xiu-Bo

2010-07-01

360

Supported polytertiary amines: highly efficient and selective SO2 adsorbents.  

Science.gov (United States)

Tertiary amine containing poly(propyleneimine) second (G2) and third (G3) generation dendrimers as well as polyethyleneimine (PEI) were developed for the selective removal of SO2. N-Alkylation of primary and secondary amines into tertiary amines was confirmed by FTIR and NMR analysis. Such modified polyamines were impregnated on two nanoporous supports, namely, SBA-15PL silica with platelet morphology and ethanol-extracted pore-expanded MCM-41 (PME) composite. In the presence of 0.1% SO2/N2 at 23 °C, the uptake of modified PEI, G2, and G3 supported on SBA-15PL was 2.07, 2.35, and 1.71 mmol/g, respectively; corresponding to SO2/N ratios of 0.22, 0.4, and 0.3. Under the same conditions, the SO2 adsorption capacity of PME-supported modified PEI and G3 was significantly higher, reaching 4.68 and 4.34 mmol/g, corresponding to SO2/N ratios of 0.41 and 0.82, respectively. The working SO2 adsorption capacity decreased with increasing temperature, reflecting the exothermic nature of the process. The adsorption capacity of these materials was enhanced dramatically in the presence of humidity in the gas mixture. FTIR data before SO2 adsorption and after adsorption and regeneration did not indicate any change in the materials. Nonetheless, the SO2 working capacity decreased in consecutive adsorption/regeneration cycles due to evaporation of impregnated polyamines, rather than actual deactivation. FTIR and (13)C and (15)N CP-MAS NMR of fresh and SO2 adsorbed modified G3 on PME confirmed the formation of a complexation adduct. PMID:24437448

Tailor, Ritesh; Abboud, Mohamed; Sayari, Abdelhamid

2014-02-01

 
 
 
 
361

Electronic structure of benzene adsorbed on Ni and Cu surfaces  

Energy Technology Data Exchange (ETDEWEB)

Benzene has for a long time served as a prototype adsorption system of large molecules. It adsorbs with the molecular plane parallel to the surface. The bonding of benzene to a transition metal is typically viewed to involve the {pi} system. Benzene adsorbs weakly on Cu and strongly on Ni. It is interesting to study how the adsorption strength is reflected in the electronic structure of the adsorbate-substrate complex. The authors have used X-ray Emission (XE) and X-ray Absorption (XA) spectroscopies to selectively study the electronic states localized on the adsorbed benzene molecule. Using XES the occupied states can be studies and with XAS the unoccupied states. The authors have used beamline 8.0 and the Swedish endstation equipped with a grazing incidence x-ray spectrometer and a partial yield absorption detector. The resolution in the XES and XAS were 0.5 eV and 0.05 eV, respectively.

Weinelt, M.; Nilsson, A.; Wassdahl, N. [Uppsala Univ. (Sweden)] [and others

1997-04-01

362

Atomic scale friction of molecular adsorbates during diffusion  

CERN Document Server

Experimental observations suggest that molecular adsorbates exhibit a larger friction coefficient than atomic species of comparable mass, yet the origin of this increased friction is not well understood. We present a study of the microscopic origins of friction experienced by molecular adsorbates during surface diffusion. Helium spin-echo measurements of a range of five-membered aromatic molecules, cyclopentadienyl (Cp), pyrrole and thiophene, on a copper(111) surface are compared with molecular dynamics simulations of the respective systems. The adsorbates have different chemical interactions with the surface and differ in bonding geometry, yet the measurements show that the friction is greater than 2 ps$^{-1}$ for all these molecules. We demonstrate that the internal and external degrees of freedom of these adsorbate species are a key factor in the underlying microscopic processes and identify the rotation modes as the ones contributing most to the total measured friction coefficient.

Lechner, B A J; Hedgeland, H; Jardine, A P; Hinch, B J; Allison, W; Ellis, J

2013-01-01

363

Separation of uranium from seawater by adsorbing colloid flotation  

International Nuclear Information System (INIS)

Hydrated titanium oxide has been investigated for use as a collector in the separation of uranium from seawater using adsorbing colloid flotation. The main recovery is 91% and the optimum pH 6.6 +- 0.2. (author)

364

TESTING OF CARBONACEOUS ADSORBENTS FOR REMOVAL OF POLLUTANTS FROM WATER  

Directory of Open Access Journals (Sweden)

Full Text Available Testing of carbonaceous adsorbents for removal of pollutants from water. Relevant direction for improving of quality of potable water is application of active carbons at various stages of water treatments. This work includes complex research dealing with testing of a broad spectrum of carbonaceous adsorbents for removal of hydrogen sulfide and nitrite ions from water. The role of the surface functional groups of carbonaceous adsorbents, their acid-basic properties, and the influence of the type of impregnated heteroatom (N, O, or metals (Fe, Cu, Ni, on removal of hydrogen sulfide species and nitrite ions have been researched. The efficiency of the catalyst obtained from peach stones by impregnation with Cu2+ ions of oxidized active carbon was established, being recommended for practical purposes to remove the hydrogen sulfide species from the sulfurous ground waters. Comparative analysis of carbonaceous adsorbents reveals the importance of surface chemistry for oxidation of nitrite ions.

RAISA NASTAS

2012-03-01

365

SUPERCRITICAL FLUID EXTRACTION OF PARTICULATE AND ADSORBENT MATERIALS  

Science.gov (United States)

The report is a summary of work performed by PNL on the extraction of semivolatile organic materials (SVOCs), for example, polynuclear aromatic compounds, from various adsorbents and environmental matrices, using supercritical fluids (SCFs) as extractants. The results of the work...

366

Anomalous thermal denaturing of proteins adsorbed to nanoparticles  

Science.gov (United States)

We have used localized surface plasmon resonance (LSPR) to monitor the structural changes that accompany thermal denaturing of bovine serum albumin (BSA) adsorbed onto gold nanospheres of size 5nm-60nm. The effect of the protein on the LSPR was monitored by visible extinction spectroscopy. The position of the resonance is affected by the conformation of the adsorbed protein layer, and as such can be used as a very sensitive probe of thermal denaturing that is specific to the adsorbed protein. The results are compared to detailed calculations and show that full calculations can lead to significant increases in knowledge where gold nanospheres are used as biosensors. Thermal denaturing on spheres with diameter > 20 nm show strong similarity to bulk calorimetric studies of BSA in solution. BSA adsorbed on nanospheres with d ? 15nm shows a qualitative difference in behavior, suggesting a sensitivity of denaturing characteristics on local surface curvature. This may have important implications for other protein-nanoparticle interactions.

Teichroeb, J. H.; Forrest, J. A.; Ngai, V.; Jones, L. W.

2006-09-01

367

Oil palm biomass as an adsorbent for heavy metals.  

Science.gov (United States)

Many industries discharge untreated wastewater into the environment. Heavy metals from many industrial processes end up as hazardous pollutants of wastewaters.Heavy metal pollution has increased in recent decades and there is a growing concern for the public health risk they may pose. To remove heavy metal ions from polluted waste streams, adsorption processes are among the most common and effective treatment methods. The adsorbents that are used to remove heavy metal ions from aqueous media have both advantages and disadvantages. Cost and effectiveness are two of the most prominent criteria for choosing adsorbents. Because cost is so important, great effort has been extended to study and find effective lower cost adsorbents.One class of adsorbents that is gaining considerable attention is agricultural wastes. Among many alternatives, palm oil biomasses have shown promise as effective adsorbents for removing heavy metals from wastewater. The palm oil industry has rapidly expanded in recent years, and a large amount of palm oil biomass is available. This biomass is a low-cost agricultural waste that exhibits, either in its raw form or after being processed, the potential for eliminating heavy metal ions from wastewater. In this article, we provide background information on oil palm biomass and describe studies that indicate its potential as an alternative adsorbent for removing heavy metal ions from wastewater. From having reviewed the cogent literature on this topic we are encouraged that low-cost oil-palm-related adsorbents have already demonstrated outstanding removal capabilities for various pollutants.Because cost is so important to those who choose to clean waste streams by using adsorbents, the use of cheap sources of unconventional adsorbents is increasingly being investigated. An adsorbent is considered to be inexpensive when it is readily available, is environmentally friendly, is cost-effective and be effectively used in economical processes. The advantages that oil palm biomass has includes the following:available and exists in abundance, appears to be effective technically, and can be integrated into existing processes. Despite these advantages, oil palm biomasses have disadvantages such as low adsorption capacity, increased COD, BOD and TOC. These disadvantages can be overcome by modifying the biomass either chemically or thermally. Such modification creates a charged surface and increases the heavy metal ion binding capacity of the adsorbent. PMID:24984835

Vakili, Mohammadtaghi; Rafatullah, Mohd; Ibrahim, Mahamad Hakimi; Abdullah, Ahmad Zuhairi; Salamatinia, Babak; Gholami, Zahra

2014-01-01

368

Carbon-13 NMR investigation of acetone adsorbed on silica gel  

International Nuclear Information System (INIS)

The 13C chemical shift of acetone adsorbed on silica gel has been measured as a function of adsorbate coverage and concentration of surface hydroxyl groups. The experimental data can be interpreted by a theoretical model for the adsorption, based upon the BET-theory with two different adsorption mechanisms for acetone in the first monomolecular layer (hydrogen bonding and not hydrogen bonding). The concentration of acetone in different adsorption sites and the chemical shift in these sites have been obtained. (orig.)

369

Experimental study on extraction chromatography using CMPO adsorbent  

International Nuclear Information System (INIS)

In order to study the applicability of extraction chromatographic method to the TRUEX and SETFICS processes for MA separation in the program of Feasibility Study on Commercialized Fast Reactor Cycle Systems, this work investigated some basic characteristics of a novel silica-supported CMPO adsorbent. The leaching behavior of CMPO from the adsorbent by specified eluent solutions, adsorption capacity, dissolution method of CMPO form the support and thermal decomposition performance have been examined experimentally. The experimental results indicate that the leaching of CMPO from the adsorbent is resulted from the solubility of CMPO in an eluent solution. The dissolubility by a dilute nitric acid is relatively high and the concentration of leached CMPO is about 20-50 ppm. It was found that almost the same amount of CMPO is leached out from the adsorbent packed column during the elution operation. However, the leaching problem of CMPO would be cleared by packing an extra amount of the adsorbent to column or by using the eluent solutions saturated by CMPO. The adsorption capacity of the CMPO adsorbent for Nd(III) in 3M HNO3 solution was measured as 0.19-0.22 mmol/g, which is approximately 70-80% of the maximum adsorption amount as M(NO3)3·3 CMPO. The impregnated CMPO can be completely dissolved out from the support by an organic solvent such as acetone. From the thermal analysis results, it was recognized that CMPO in the adsorbent decompognized that CMPO in the adsorbent decomposed at 200degC and the SDB-polymer at 290degC, leaving the silica particles. (author)

370

A strong adsorbent for Cu²?: graphene oxide modified with triethanolamine.  

Science.gov (United States)

A strong adsorbent TEA-GO for Cu(2+) is prepared using TEA modified GO nanosheets. FT-IR and XPS results show that epoxy groups on GO are eliminated, and simultaneously hydroxyl groups and C-N dominate the surface groups of TEA-GO. The increased equilibrium capacity of TEA-GO for a high initial concentration of Cu(2+) makes it a promising adsorbent for heavy metal ions. PMID:24671297

Liu, Gonggang; Gui, Shan; Zhou, Hao; Zeng, Fantao; Zhou, Yonghua; Ye, Hongqi

2014-05-21

371

Linear response theory of activated surface diffusion with interacting adsorbates  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Activated surface diffusion with interacting adsorbates is analyzed within the Linear Response Theory framework. The so-called interacting single adsorbate model is justified by means of a two-bath model, where one harmonic bath takes into account the interaction with the surface phonons, while the other one describes the surface coverage, this leading to defining a collisional friction. Here, the corresponding theory is applied to simple systems, such as diffusion on flat s...

Martinez-casado, R.; Sanz, A. S.; Vega, J. L.; Rojas-lorenzo, G.; Miret-artes, S.

2009-01-01

372

USING OF NATURAL ADSORBENTS IN PROCESSES OF PETROLEUM PRODUCTS’ CLEARING  

Directory of Open Access Journals (Sweden)

Full Text Available  Questions, that concern the ability to use natural sorbent – poligorskite of Cherkassy deposit – in processes of petroleum products’ clearing, are considered. The influence of different methods of samples’ preparation on efficiency of adsorption clearing of furnace fuel, is researched. Comparative characteristic of adsorbent’s selectivity toward different pollutions was made. High effectiveness of using of natural poligorskite for extraction of acidic pollutions from petroleum products was showed.

Sergey V. Ivanov

2008-02-01

373

Development of an adsorbent for both cesium and strontium  

International Nuclear Information System (INIS)

Described is the development of the adsorbent in the title at the process of developing the agent to adsorb each element. For cooling the reactors injured by the Fukushima Nuclear Power Plant Accident by the earthquake and tsunami on the day before (Mar. 11, 2011), fresh/ sea water is supplied in the reactor and flows out contaminated with radioactive elements in the turbine building and then in the treatment plant to remove oil and cesium for re-circulation to the reactor. Water from the plant still contains radioisotopes derived from fission, like 90Sr/90Y at 1.2 x 108 Bq/L and 137Cs/137mBa at 6.1 x 103 Bq/L, and from activation of reactor materials. Before the plant, the water contains 137Cs at the level as high as 4.1 x 107 Bq/L. Authors have examined various agents to adsorb 90Sr and 137Cs with a measure of partition coefficient Kd (L of the artificial sea water/kg) and have come to find out the adsorbent in the title: it is derived from the Cs-adsorbing crystalized silico-titanate (CST). The adsorbent is obtainable by surface treatment of CST with NaOH and has high Kds of >1 x 103 and >1 x 104 L/kg for Sr and Cs, respectively, while other ordinary adsorbents' Kds are: artificial zeolite 1-10 x 102/1-10 x 101 for Sr/Cs, respectively; natural one 0.1-10 x 101/1-10 x 102; ferrocyanide 0.1-10 x 101/1-10 x 104, and CST 1 x 101/>1 x 104. When 1 m3 of the present adsorbent is used, >99% of Cs and Sr can be removable in >3,000 m3 of contaminated water, suggesting its usefulness for dealing with water after the Accident. (T.T.)

374

Field electron emission and stochastic processes of adsorbates  

International Nuclear Information System (INIS)

After a review of the long tradition of field emission experiments in Leipzig, the investigations of field emission current noise supervised initially by Gustav Hertz are described and traced back to elementary processes of the adsorbate dynamics. The subsequent development of a method for the determination of surface diffusion parameters is discussed. Cross-correlation measurements indicate a soliton dynamics in special adsorbate submonolayers. (author)

375

Vanadium (4) complexing in phase of adsorbent with benzimidazole groups  

International Nuclear Information System (INIS)

Equilibrium and kinetic characteristics of V4+ sorption by POLYORGS XI-H adsorbent with benzimidazole groups (BIm) are investigated. Using ESR method it is stated that [VO2+]:[BIm]1:2 complex, where VO2+ is combined with nitrogen atoms of two imidazole groups, is formed in adsorbent phase. The highest distribution factor of 4.7x103 is attained at pH6

376

In vitro efficacy of mycotoxins adsorption by natural mineral adsorbents  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The paper describes in vitro model for evaluation of natural mineral adsorbents ability to adsorb mycotoxins. Bentonite, diatomite and zeolite were prepared in the Institute for Technology of Nuclear and Other Mineral Raw Materials, Belgrade. A total of six mycotoxins: aflatoxin B1 (AFL), ochratoxin A (OTA), deoxynivalenol (DON), zearalenone (ZON), diacetoxyscirpenol (DAS) and T-2 toxin were tested in vitro. For adsorption experiments crude extracts of myco...

Bo?arov-Stan?i? A.; Adamovi? M.; Salma N.; Bodroža-Solarov M.; Vu?kovi? J.; Panti? V.

2011-01-01

377

Enhancement of dissolution profile of gliclazide by solid dispersion adsorbates  

Digital Repository Infrastructure Vision for European Research (DRIVER)

This article investigates enhancement of the dissolution profile of gliclazide, an antidiabetic drug, using the combination of solid dispersions and melt adsorption techniques. Poloxamer and PEG 6000 were utilized as hydrophilic carriers for solid dispersions preparation and lactose selected on the basis of preliminary studies was utilized as an adsorbent for the preparation of solid dispersion adsorbates. The techniques of FTIR spectroscopy, differential scanning calorimetry (DSC), and X-ray...

Singh, Narender; Arora, Ashish; Kaushik, Deepak

2011-01-01

378

Microstructural and mechanical property evaluation of black chrome and zinc oxide coated solar collectors. Annual report No. II, June 1979-March 1980  

Energy Technology Data Exchange (ETDEWEB)

Plating parameters for black-chrome system were optimized with respect to selectivity utilizing simplex evolutionary operation procedures in sixteen sets of experiments. Overgrowths produced with the optimized parameters were then evaluated for optical, structural, thermal stability and mechanical properties. It is observed that the coatings produced possess consistently high selectivity values (approx. 10), are durable against exposure to high temperature (> 400/sup 0/C in air and > 500/sup 0/C in neutral atmosphere), are well attached to their structure (> 340 kg/cm/sup 2/), and are quite ductile (bent to 131.5/sup 0/ previous to fracture) and reasonably remain so following exposure to 500/sup 0/C (2 hrs) in air (84.2% bend previous to fracture). Black zinc oxide surfaces created on leaf zinc, electroplated zinc on steel, and hot-dip zinc coated steel substrates show selectivity values that vary between 6-9, are seen to maintain their physical integrity as well as optical properties following exposure to 250/sup 0/C (2 hrs) in air, possess high strength of attachment to their substrates (> 285 kg/cm/sup 2/), and are quite ductile (170/sup 0/ bend previous to fracture) and maintain a reasonably high ductility (121/sup 0/ bend previous to fracture) following exposure to 250/sup 0/C (2 hrs) in air. Structural analysis of both overgrowths show them to consist of oxide particles within which elemental component of the oxide is seen to be distributed in the unassociated form. The plating parameters utilized in deposition of the coatings are seen to alter quantity and distribution of the elemental component and effect optical properties of these surfaces. These composite particles are seen to be of various sizes but the distribution of these particles are seen to be constant throughout the overgrowth.

Inal, O T

1980-01-01

379

Application of silver impregnated iodine adsorbent to nuclear facilities  

International Nuclear Information System (INIS)

Radioactive iodine is one of the most important nuclides to be prevented for release from nuclear facilities and many facilities have off-gas treatment systems to minimize the volatile nuclides dispersion to the environment. Silver impregnated inorganic adsorbents were known as inflammable and stable fixing materials for iodine and the authors started to develop 25 years ago a kind of inorganic adsorbent that has better capability compared with conventional ones. Aluminum oxide (Alumina) was selected as a carrier material and silver nitrate as an impregnated one. Pore diameters were optimized to avoid the influence of impurities such as humidity in the off-gas stream at lower temperatures. Experiments and improvements were alternately conducted for the new adsorbent. The tests were carried out in various conditions to confirm the performance of the developed adsorbent, which clarified its good ability to remove iodine. Silver nitrate impregnated alumina adsorbent (AgA) has about twice the capacity for iodine adsorption and higher iodine removal efficiency at relatively high humidity than conventional ones. The AgA chemically and stably fixes radioactive iodine and fits the storage and disposal of used adsorbent. AgA is now and will be applied to nuclear power plants, reprocessing plants, and research facilities. (author)

380

Adsorption of noble gas on various adsorbents at cryogenic temperatures  

International Nuclear Information System (INIS)

Most of 85Kr in atmosphere is released from anthropogenic sources such as tests of nuclear weapons and nuclear reactors. As a chemically inert gas with a long half-life, 85Kr will continue to accumulate in the environment. Thus, it is necessary to monitor the background level of the atmospheric 85Kr concentrations. In this study, the authors conducted a screening test of several adsorbents to search for more suitable one for adsorption of Kr at under nitrogen atmosphere, which is used for the monitoring system of 85Kr. A screening test was carried out by focusing on adsorption characteristics at a cryogenic temperature. With regard to adsorbents selected in the screening test, more detailed adsorption characteristics were examined. As a result, it was found that carbon based adsorbents have better performance for adsorption of Kr and that the Ambersorb 572 adsorbent has the largest adsorption capacity. It was also found that the adsorption capacity of non-carbon based adsorbents is much lower than that of carbon-based adsorbents. (author)

 
 
 
 
381

Gold recovery from low concentrations using nanoporous silica adsorbent  

Science.gov (United States)

The development of high capacity adsorbents with uniform porosity denoted 5%MP-HMS (5% Mercaptopropyl-Hexagonal Mesoporous Structure) to extract gold from noncyanide solutions is presented. The preliminary studies from laboratory simulated noncyanide gold solutions show that the adsorption capacities of these materials are among the highest reported. The high adsorption saturation level of these materials, up to 1.9 mmol/g (37% of the adsorbent weight) from gold chloride solutions (potassium tetrachloroaurate) and 2.9 mmol/g (57% of the adsorbent weight) from gold bromide solutions (potassium tetrabromoaurate) at pH = 2, is a noteworthy feature of these materials. This gold loading from [AuC4]- and [AuBr4 ]- solutions corresponds to a relative Au:S molar ratio of 2.5:1 and 3.8:1, respectively. These rates are significantly higher than the usual 1:1 (Au:S) ratio expected for metal ion binding with the material. The additional gold ions loaded have been spontaneously reduced to metallic gold in the mesoporous material. Experimental studies indicated high maximum adsorptions of gold as high as 99.9% recovery. Another promising attribute of these materials is their favourable adsorption kinetics. The MP-HMS reaches equilibrium (saturation) in less than 1 minute of exposure in gold bromide and less than 10 minutes in gold chloride. The MP-HMS materials adsorption is significantly improved by agitation and the adsorption capacity of Au (III) ions increases with the decrease in pH. The recovery of adsorbed gold and the regeneration of spent adsorbent were investigated for MP-HMS adsorbent. The regenerated adsorbent (MP-HMS) maintained its adsorption capacity even after repeated use and all the gold was successfully recovered from the spent adsorbent. For the fist time, a promising adsorbent system has been found that is capable of effectively concentrating gold thiosulphate complexes, whereas conventional carbon-inpulp (CIP) and carbon-in-leach (CIL) systems fail. The gold adsorption shows the high affinity of the mesoporous material to the gold-thiosulphate ([Au (S2O3)2]3- ) ions. A high adsorption saturation level for these materials was found, up to 0.25 mmol (5 mg) Au/g of HMS from gold-thiosulphate solutions. When ammonia was added to the thiosulphate solutions, with or without added copper, the mesoporous material (HMS) achieved the maximum adsorption, 0.24 mmol (47 mg) Au/g of HMS at pH = 7, where as 0.14 mmol (28 mg) Au/g was adsorbed from ammonia-thiosulphate solution at pH > 6. For the fist time, a promising adsorbent system has been found that is capable of effectively concentrating gold thiosulphate complexes, whereas conventional carbon-in-pulp (CIP) and carbon-in-leach (CIL) systems fail. For process design of gold adsorption by HMS particles, certain engineering conditions and practical limitations have to be considered, including particle size of the MP-HMS. Therefore, several experiments have been conducted to enlarge the size of the very fine MP-HMS particles to a size (1--2mm) satisfying the engineering requirements for process design in a real practical and industrial process. The agglomerated mesoporous materials, using sodium metasilicate (Na 2SiO3) binder, adsorbed gold ions in the range of 51%--63% of what the parent HMS powder adsorb. That means the agglomerates can adsorb 19--23% of their own weight (or 190--230 mg Au per one gram of the agglomerated HMS) from [AuCL4]- which is still very satisfactory and acceptable comparing to the current used adsorbents.

Aledresse, Adil

382

Preparation of a new adsorbent from activated carbon and carbon nanofiber (AC/CNF) for manufacturing organic-vacbpour respirator cartridge.  

Science.gov (United States)

In this study a composite of activated carbon and carbon nanofiber (AC/CNF) was prepared to improve the performance of activated carbon (AC) for adsorption of volatile organic compounds (VOCs) and its utilization for respirator cartridges. Activated carbon was impregnated with a nickel nitrate catalyst precursor and carbon nanofibers (CNF) were deposited directly on the AC surface using catalytic chemical vapor deposition. Deposited CNFs on catalyst particles in AC micropores, were activated by CO2 to recover the surface area and micropores. Surface and textural characterizations of the prepared composites were investigated using Brunauer, Emmett and Teller's (BET) technique and electron microscopy respectively. Prepared composite adsorbent was tested for benzene, toluene and xylene (BTX) adsorption and then employed in an organic respirator cartridge in granular form. Adsorption studies were conducted by passing air samples through the adsorbents in a glass column at an adjustable flow rate. Finally, any adsorbed species not retained by the adsorbents in the column were trapped in a charcoal sorbent tube and analyzed by gas chromatography. CNFs with a very thin diameter of about 10-20 nm were formed uniformly on the AC/CNF. The breakthrough time for cartridges prepared with CO2 activated AC/CNF was 117 minutes which are significantly longer than for those cartridges prepared with walnut shell- based activated carbon with the same weight of adsorbents. This study showed that a granular form CO2 activated AC/CNF composite could be a very effective alternate adsorbent for respirator cartridges due to its larger adsorption capacities and lower weight. PMID:23369424

Jahangiri, Mehdi; Adl, Javad; Shahtaheri, Seyyed Jamaleddin; Rashidi, Alimorad; Ghorbanali, Amir; Kakooe, Hossein; Forushani, Abbas Rahimi; Ganjali, Mohammad Reza

2013-01-01

383

On the effect of coverage-dependent adsorbate-adsorbate interactions for CO methanation on transition metal surfaces  

DEFF Research Database (Denmark)

Heterogeneously catalyzed reactions involving the dissociation of strongly bonded molecules typically need quite reactive catalysts with high coverages of intermediate molecules. Methanation of carbon monoxide is one example, where CO dissociation has been reported to take place on step sites with a high coverage of CO. At these high coverages, reaction intermediates experience interaction effects that typically reduce their adsorption energies. Herein, the effect of these interactions on the activities of transition metals for CO methanation is investigated. For transition metals that have low coverages of reactants, the effect is minimal. But for materials with high coverages under reaction conditions, rates can change by several orders of magnitude. Nevertheless, the position of the maximum of the activity volcano does not shift significantly, and the rates at the maximum are only slightly perturbed by adsorbate-adsorbate interactions. In order to accurately describe selectivities, however, adsorbate-adsorbate interactions will likely need to be included.

Lausche, Adam C.; Medford, Andrew J.

2013-01-01

384

Phase transfer of agglomerated nanoparticles: deagglomeration by adsorbing grafted molecules and colloidal stability in polymer solutions  

International Nuclear Information System (INIS)

A study is presented, where agglomerated magnetite nanoparticles with a crystallite size of 15 nm are transferred from water to an immiscible organic phase and tend to deagglomerate under certain conditions using different types of chemically adsorbing fatty acid. It is shown that the longer fatty acids lead to more stable dispersions and for the longest fatty acids, the functionality of the molecules defines stability with best results for ricinoleic acid. The disjoining force as a function of the brush layer thickness and adsorption density is calculated with a physical model applying the well-established Alexander de Gennes theory. We further investigate the colloidal stability of the transferred and stabilized magnetite nanocrystals in polymer solutions of destabilizing PMMA and stabilizing PVB. A DLVO-like theory presents the governing attractive and repulsive interactions for the case of destabilizing non-adsorbing polymers. The theory can be used to explain the influencing parameters in a mixture of sterically stabilized nanoparticles in an organic solvent based solution of polymer coils. Finally, by spray drying, we produce polymer–nanoparticle composite microparticles. Based on BET, laser diffraction and backscatter electron SEM measurements, we draw conclusions on the nanoparticle distribution within the composite in correlation with the stability investigations.

385

Phase transfer of agglomerated nanoparticles: deagglomeration by adsorbing grafted molecules and colloidal stability in polymer solutions  

Energy Technology Data Exchange (ETDEWEB)

A study is presented, where agglomerated magnetite nanoparticles with a crystallite size of 15 nm are transferred from water to an immiscible organic phase and tend to deagglomerate under certain conditions using different types of chemically adsorbing fatty acid. It is shown that the longer fatty acids lead to more stable dispersions and for the longest fatty acids, the functionality of the molecules defines stability with best results for ricinoleic acid. The disjoining force as a function of the brush layer thickness and adsorption density is calculated with a physical model applying the well-established Alexander de Gennes theory. We further investigate the colloidal stability of the transferred and stabilized magnetite nanocrystals in polymer solutions of destabilizing PMMA and stabilizing PVB. A DLVO-like theory presents the governing attractive and repulsive interactions for the case of destabilizing non-adsorbing polymers. The theory can be used to explain the influencing parameters in a mixture of sterically stabilized nanoparticles in an organic solvent based solution of polymer coils. Finally, by spray drying, we produce polymer-nanoparticle composite microparticles. Based on BET, laser diffraction and backscatter electron SEM measurements, we draw conclusions on the nanoparticle distribution within the composite in correlation with the stability investigations.

Rudolph, Martin, E-mail: martin.rudolph@mvtat.tu-freiberg.de [Helmholtz-Institute Freiberg for Resource Technology (Germany); Peuker, Urs Alexander [TU Bergakademie Freiberg, Institute of Mechanical Process Engineering and Minerals Processing (Germany)

2012-07-15

386

New sulfur adsorbents derived from layered double hydroxides. Part 1. Synthesis and COS adsorption  

Energy Technology Data Exchange (ETDEWEB)

Mixed oxides, prepared via the thermal decomposition of layered double hydroxides (LDHs), were screened gravimetrically for their ability to adsorb carbonyl sulfide (COS). Based on promising results obtained for Ni/Mg/Al, Ni/Mg/Fe and Co/Mg/Al mixed oxides, a study was undertaken to optimize the composition of these materials for COS adsorption. To investigate the effect of the M(II):M(III) ratio, LDHs of the type [M{sub z}Mg{sub y}Al{sub x}(OH){sub 2}](CO{sub 3}){sub x/2}.0.5H{sub 2}O (where M = Ni or Co, and x + y + z 1) were prepared at values of x corresponding to 0.33 and 0.20. Simultaneously, the elemental ratio of transition metal to magnesium (z/y) was varied. Mixed oxides obtained from the resulting LDHs were tested in fixed bed mode with a feed of 100 ppm COS in N{sub 2} to determine breakthrough capacity. In general Ni/Mg/Al mixed oxides showed the best performance, a composition with Ni/Mg/Al = 0.32/0.48/0.20 showing the best adsorption capacity. Treatment of the spent adsorbent under an atmosphere of 5% H{sub 2} in N{sub 2} at 450 C was found to provide an effective means of restoring the adsorption capacity over two cycles of adsorption and regeneration, although after three such cycles, adsorption capacity decreased. (author)

Sparks, Dennis E.; Morgan, Tonya; Patterson, Patricia M.; Tackett, S. Adam; Morris, Erin; Crocker, Mark [Center for Applied Energy Research, University of Kentucky, 2540 Research Park Drive, Lexington, KY 40511-8479 (United States)

2008-08-08

387

Adsorption and desorption behavior of tetravalent zirconium onto a silica-based macroporous TODGA adsorbent in HNO3 solution  

International Nuclear Information System (INIS)

To understand the separation behavior of Zr(IV) in the partitioning process for high level liquid waste, a silica-based macroporous adsorbent (TODGA/SiO2-P) was prepared by impregnating N,N,N',N'-tetraoctyl-3-oxapentane-1,5-diamide (TODGA) into a macroporous silica/polymer composite particles support (SiO2-P). Adsorption and desorption behavior of Zr(IV) from nitric acid solution onto silica-based TODGA/SiO2-P adsorbent were investigated by batch experiment. It was found that TODGA/SiO2-P showed strong adsorption affinity to Zr(IV) and this adsorption process reached equilibrium state around 6 h at 298 K. Meanwhile, HNO3 concentration had no significant effect on the adsorption of Zr(IV) above 1 M. From calculated thermodynamic parameters, this adsorption process could occur spontaneously at the given temperature and was confirmed to be an exothermic reaction. This adsorption process could be expressed by Langmuir monomolecular layer adsorption mode and the maximum adsorption capacity were determined to be 0.283 and 0.512 mmol/g for Zr(IV) at 298 and 323 K, respectively. In addition, more than 90 % of Zr(IV) adsorbed onto adsorbent could be desorbed with 0.01 M diethylenetriamine pentaacetic acid solution within 24 h at 298 K. (author)

388

Development of a cyclodextrin production process using specific adsorbents.  

Science.gov (United States)

Novel adsorbents that are composed of ligand, spacer, and support were chemically synthesized, and the two consecutive screenings made it possible to determine the adsorbents that were most suitable for alpha- and beta-CD production, respectively. Stearic acid was the most effective ligand for alpha-CD, whereas cyclohexanepropanamide-n-caproic acid was best for beta-CD. The adsorption selectivity of adsorbents derived from carboxylic acids (stearic or palmitic acid) and Chitosan beads was almost 100%, and their adsorption capacities were large enough to meet the demand for economical production and purification of CDs on an industrial scale. Next we discussed a novel process of alpha-CD production using the newly synthesized adsorbent characterized by the exceedingly powerful selectivity of alpha-CD from other CDs. alpha-CD production was carried out in the closed system converted to CDs by CGTase, and the column was packed with the adsorbent selective for alpha-CD. The yield of alpha-CD was 22.3%, and alpha-CD occupied a fraction of 57.4% in the overall CD reaction mixture. In the batch system without adsorbent, the yields of alpha-CD and its fraction were 10.8 and 24%, respectively. This novel process is particularly useful for the large-scale production of alpha-CD, in which the use of organic solvent is not preferable. We will now develop a novel process for the industrial production of CDs other than alpha-CD, such as gamma-CD, by using specific adsorbents. PMID:7763343

Okabe, M; Tsuchiyama, Y; Okamoto, R

1993-01-01

389

Magnetic niobia as adsorbent of organic contaminants in aqueous medium: effect of temperature and pH  

International Nuclear Information System (INIS)

This work describes novel materials based on pure iron oxide and iron oxide/niobia composite to produce a magnetic adsorbent. These materials were prepared with synthetic iron oxide and characterized by powder XRD, SEM, FTIR, TPR and Moessbauer spectroscopy. Results showed that the main iron oxides formed were goethite (? FeOOH) and maghemite (?Fe2O3) with small particle size. The iron oxide and iron oxide/niobia composite showed high adsorption ability for organic compounds. The positive enthalpy indicated an endothermic adsorption process suggesting physical adsorption. (author)

390

Synthesis of arsenic graft adsorbents in pilot scale  

Science.gov (United States)

Synthesis of arsenic (As) adsorbents in pilot scale was carried out with a synthesizing apparatus by radiation-induced graft polymerization of 2-hydroxyethyl methacrylate phosphoric acid monomer (PA), which consists of phosphoric acid mono- (50%) and di- (50%) ethyl methacrylate esters onto a nonwoven cotton fabric (NCF), and following chemical modification by contact with a zirconium (Zr) solution. The apparatus which was equipped with reaction tanks, a washing tank and a pump can produce up to 0.3 m×14 m size of the As(V) adsorbent in one reaction. A degree of grafting of 150% was obtained at an irradiation dose of 20 kGy with 5% of PA solution mixed with deionized water for 1 h at 40 °C. Finally, after Zr(IV) was loaded onto a NCF with 5 mmol/L of Zr(IV) solution, the graft adsorbent for the removal of As(V) was achieved in pilot-scale. The adsorbent which was synthesized in pilot scale was evaluated in batch mode adsorption with 1 ppm (mg/l) of As(V) solution for 2 h at room temperature. As a result, the adsorption capacity for As(V) was 0.02 mmol/g-adsorbent.

Hoshina, Hiroyuki; Kasai, Noboru; Shibata, Takuya; Aketagawa, Yasushi; Takahashi, Makikatsu; Yoshii, Akihiro; Tsunoda, Yasuhiko; Seko, Noriaki

2012-08-01

391

High capacity cryogel-type adsorbents for protein purification.  

Science.gov (United States)

Cryogel bodies were modified to obtain epoxy groups by graft-copolymerization using both chemical and gamma irradiation initiation techniques. The free epoxy adsorbents were reacted further to introduce diethylaminoethanol (DEAE) functionalities. The resulting weak anion-exchange cryogel adsorbents showed dynamic binding capacities of ca. 27±3mg/mL, which was significantly higher than previously reported for this type of adsorbent material. Gamma irradiated grafting initiation showed a 4-fold higher capacity for proteins than chemical grafting initiation procedures. The phosphate capacity for these DEAE cryogels was 119mmol/L and also showed similar column efficiency as compared to commercial adsorbents. The large pores in the cryogel structure ensure convective transport of the molecules to active binding sites located on the polymer-grafted surface of cryogels. However, as cryogels have relatively large pores (10-100?m), the BET area available for surface activation is low, and consequently, the capacity of the cryogels is relatively low for biomolecules, especially when compared to commercial beaded adsorbents. Nevertheless, we have shown that gamma ray mediated surface grafting of cryogel matrices greatly enhance their functional and adsorptive properties. PMID:24980092

Singh, Naveen Kumar; Dsouza, Roy N; Grasselli, Mariano; Fernández-Lahore, Marcelo

2014-08-15

392

Sprayable titanium composition  

Science.gov (United States)

The addition of 2-ethyl-1-hexanol to an organometallic titanium compound dissolved in a diluent and optionally containing a lower aliphatic alcohol spreading modifier, produces a solution that can be sprayed onto a substrate and cured to form an antireflection titanium oxide coating having a refractive index of from about 2.0 to 2.2.

Tracy, Chester E. (South River, NJ); Kern, Werner (Belle Mead, NJ); Vibronek, Robert D. (Sayreville, NJ)

1980-01-01

393

Mixed composition materials suitable for vacuum web sputter coating  

Science.gov (United States)

Ion beam sputter deposition techniques were used to investigate simultaneous sputter etching of two component targets so as to produce mixed composition films. Although sputter deposition has been largely confined to metals and metal oxides, at least one polymeric material, poly-tetra-fluorethylene, has been demonstrated to produce sputtered fragments which repolymerize upon deposition to produce a highly cross-linked fluoropolymer resembling that of the parent target Fluoropolymer-filled silicon dioxide and fluoropolymer-filled aluminum oxide coatings have been deposited by means of ion beam sputter coat deposition resulting in films having material properties suitable for aerospace and commercial applications. The addition of fluoropolymer to silicon dioxide films was found to increase the hydrophobici