The inter-adsorbate interaction mediated by Shockley-type surface state electrons and dipole moment: Cs and Ba atoms absorbed on Ag (1 1 1) films

Energy Technology Data Exchange (ETDEWEB)

Zhang, Shuyuan [College of Physical Science and Technology, Sichuan University, Chengdu 610065 (China); Zhang, Hong, E-mail: hongzhang@scu.edu.cn [College of Physical Science and Technology, Sichuan University, Chengdu 610065 (China); Key Laboratory of High Energy Density Physics and Technology of Ministry of Education, Sichuan University, Chengdu 610064 (China); Miyamoto, Yoshiyuki [Nanosystem Research Institute, National Institute of Advanced Industrial Science and Technology (AIST), Central 2, 1-1-1 Umezono, Tsukuba 305-8568 (Japan)

2014-01-15

Through first-principles investigation, we display the formation process of Shockley-type surface states which emerges on silver thin films along Ag (1 1 1) orientation with increasing thicknesses from 6 to 21 layers. We look at the surface state band for various adatoms adsorbed on 6, 12, 18 layers strained Ag (1 1 1) films with different coverage, and discuss the long range interaction mediated by surface state electrons. We discovered that film's thickness can modulate the surface state mediated interaction drastically, but the dipole–dipole repulsive interaction is not affected by slab thickness. This factor had never been discussed in detail. Therefore, adatoms adsorbed on thin films have strong attractive interaction which leads to small adsorption separation and the tendency of island formation. For different coverage or different adsorbate types, both surface states and dipole moment are modulated. The three factors, film's thickness, adsorbate coverage and adatoms types, could help us learn more about the interactions between adatoms and exploit advanced ways to control surface geometry structures of self-assembly.

The inter-adsorbate interaction mediated by Shockley-type surface state electrons and dipole moment: Cs and Ba atoms absorbed on Ag (1 1 1) films

International Nuclear Information System (INIS)

Zhang, Shuyuan; Zhang, Hong; Miyamoto, Yoshiyuki

2014-01-01

Through first-principles investigation, we display the formation process of Shockley-type surface states which emerges on silver thin films along Ag (1 1 1) orientation with increasing thicknesses from 6 to 21 layers. We look at the surface state band for various adatoms adsorbed on 6, 12, 18 layers strained Ag (1 1 1) films with different coverage, and discuss the long range interaction mediated by surface state electrons. We discovered that film's thickness can modulate the surface state mediated interaction drastically, but the dipole–dipole repulsive interaction is not affected by slab thickness. This factor had never been discussed in detail. Therefore, adatoms adsorbed on thin films have strong attractive interaction which leads to small adsorption separation and the tendency of island formation. For different coverage or different adsorbate types, both surface states and dipole moment are modulated. The three factors, film's thickness, adsorbate coverage and adatoms types, could help us learn more about the interactions between adatoms and exploit advanced ways to control surface geometry structures of self-assembly.

Intramolecular and Lattice Melting in n-Alkane Monolayers: An Analog of Melting in Lipid Bilayers

DEFF Research Database (Denmark)

Hansen, Flemming Yssing; Herwig, K.W.; Matthies, B.

1999-01-01

Molecular dynamics (MD) simulations and neutron diffraction experiments have been performed on n-dotriacontane (n-C32D66) monolayers adsorbed on a graphite basal-plane surface. The diffraction experiments show little change in the crystalline monolayer structure up to a temperature of similar to ...

Characteristic electron energy loss in lanthanum films adsorbed on tungsten (110) single crystal

International Nuclear Information System (INIS)

Gorodetskij, D.A.; Gorchinskij, A.D.; Kobylyanskij, A.V.

1988-01-01

The spectrum of electron energy loss (ELS) in a wide range of energy loss 0-150 eV has been studied for La films adsorbed on W(110) single crystal with the coverage Θ from submonolayer to a few monolayers. The concentration dependence of loss energy peaks amplitude of different nature has been studied for the adsorption of rare earth element on refractory substrate. It has been shown that the essential information for the interpretation of the energy loss nature may be obtained by the investigation of such dependences for La adsorption on W(110). It is found that the surface and bulk plasmons peaks appear in ELS of La-W(110) system before the completion of the physical monolayer. Thus, the collectivization of valence electrons in the rare earth element film at the transition metal surface ensues for the submonolayer coverage like in the case of collective processes in alkali and alkaline earth element films

The Dynamics and Structures of Adsorbed Surfaces

DEFF Research Database (Denmark)

Nielsen, M; Ellenson, W. D.; McTague, J. P.

1978-01-01

. 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...

Tribochemical synthesis of nano-lubricant films from adsorbed molecules at sliding solid interface: Tribo-polymers from α-pinene, pinane, and n-decane

Science.gov (United States)

He, Xin; Barthel, Anthony J.; Kim, Seong H.

2016-06-01

The mechanochemical reactions of adsorbed molecules at sliding interfaces were studied for α-pinene (C10H16), pinane (C10H18), and n-decane (C10H22) on a stainless steel substrate surface. During vapor phase lubrication, molecules adsorbed at the sliding interface could be activated by mechanical shear. Under the equilibrium adsorption condition of these molecules, the friction coefficient of sliding steel surfaces was about 0.2 and a polymeric film was tribochemically produced. The synthesis yield of α-pinene tribo-polymers was about twice as much as pinane tribo-polymers. In contrast to these strained bicyclic hydrocarbons, n-decane showed much weaker activity for tribo-polymerization at the same mechanical shear condition. These results suggested that the mechanical shear at tribological interfaces could induce the opening of the strained ring structure of α-pinene and pinane, which leads to polymerization of adsorbed molecules at the sliding track. On a stainless steel surface, such polymerization reactions of adsorbed molecules do not occur under typical surface reaction conditions. The mechanical properties and boundary lubrication efficiency of the produced tribo-polymer films are discussed.

Conduction and TSC properties of LB films adsorbing cyanine dyes; Cyanine shikiso kyuchaku LB maku ni okeru denki dendo oyobi netsushigeki denryu tokusei

Energy Technology Data Exchange (ETDEWEB)

Shinbo, K.; Kato, K.; Kaneko, F.; Kobayashi, S. [Niigata University, Niigata (Japan)

1995-05-20

The electric properties were investigated for phosphatidic acid (PA) LB films adsorbing cyanide dyes (NK-3) with sandwich electrodes. PA LB adsorbing the dyes and the monolayers of Cd salt without the dyes are deposited using subphases, containing various concentrations of the dyes and containing CdCl2 instead of the dyes, respectively. Conduction currents are measured at room temperature for the PA LB film devices. Increases in the conduction currents are observed in the LB films containing the dyes. Furthermore, the conduction currents remarkably increase using the Au upper electrode. The current(I) vs. voltage (V) properties nearly follow the Poole conduction, log(I)-V. Therefore, the conduction currents are very complicated and are thought to be due to composite mechanisms in the film and at the interface. TSC measurements are used to examine the dipolar polarizations in the PA LB films, in the temperature region between 150 K and 300 K. Remarkable increase of TSCs are observed above 260 K for the devices containing the dyes. The TSCs are caused by the dipolar polarizations, and increase with the quantity of the dyes contained in the LB devices and/or aggregations of the dyes. The results are useful for applications of ultrathin film devices in the future. 16 refs., 11 figs., 3 tabs.

A Neutron-Diffraction Study of the Solid Layers at the Liquid Solid Boundary in 4He-Films Adsorbed on Graphite

DEFF Research Database (Denmark)

da Costa Carneiro, Kim; Passell, L.; Thomlinson, W.

1981-01-01

A neutron scattering study of the structure of 4He films adsorbed on graphite is reported. Diffraction from helium monolayers at a temperature of 1.2K shows the formation of an incommensurate, triangular-lattice solid of high density. As the coverage is increased above two layers, the diffraction...

New diffusive gradients in a thin film technique for measuring inorganic arsenic and selenium(IV) using a titanium dioxide based adsorbent

DEFF Research Database (Denmark)

Bennett, William W.; Teasdale, Peter R.; Panther, Jared G.

2010-01-01

A new diffusive gradients in a thin film (DGT) technique, using a titanium dioxide based adsorbent (Metsorb), has been developed and evaluated for the determination of dissolved inorganic arsenic and selenium. AsIII, AsV, and SeIV were found to be quantitatively accumulated by the adsorbent (uptake...... measurement of inorganic arsenic. Reproducibility of the technique in field deployments was good (relative standard deviation arsenic and 0.05 μg L-1 for SeIV. The results of this study confirmed that DGT with Metsorb was a reliable...... and robust method for the measurement of inorganic arsenic and the selective measurement of SeIV within useful limits of accuracy....

Comparative study of normal and branched alkane monolayer films adsorbed on a solid surface. I. Structure

DEFF Research Database (Denmark)

Enevoldsen, Ann Dorrit; Hansen, Flemming Yssing; Diama, A.

2007-01-01

their backbone and squalane has, in addition, six methyl side groups. Upon adsorption, there are significant differences as well as similarities in the behavior of these molecular films. Both molecules form ordered structures at low temperatures; however, while the melting point of the two-dimensional (2D......The structure of a monolayer film of the branched alkane squalane (C30H62) adsorbed on graphite has been studied by neutron diffraction and molecular dynamics (MD) simulations and compared with a similar study of the n-alkane tetracosane (n-C24H52). Both molecules have 24 carbon atoms along...... temperature. The neutron diffraction data show that the translational order in the squalane monolayer is significantly less than in the tetracosane monolayer. The authors' MD simulations suggest that this is caused by a distortion of the squalane molecules upon adsorption on the graphite surface. When...

Dotriacontane-16,17-14C distribution pattern in the respiratory system of two hamster species after passive exposure to radioactive labelled smoke

International Nuclear Information System (INIS)

Kmoch, N.; Mohr, U.

1974-01-01

The quantitative and qualitative distribution of 14 C labeled dotriacontane (DOT- 14 C) determined by liquid scintillation counting and autoradiography in the respiratory system, the digestive tract, liver and kidneys of Syrian golden and European hamsters, males and females, is described after they had been exposed to radioactive labeled cigarette smoke. The different DOT- 14 C distributions are discussed in detail with special attention given to the respiratory tract, related species differences and the topographic subdivisions of apex nasi, fundus nasi, pharynx, larynx, trachea, and lungs. It is apparent that the absolute amount of activity in the respiratory tract related to body size of the Syrian golden hamster is greater than in the European hamster but that the percentual distribution exhibits a greater filtering action of the upper respiratory tract of Syrian golden hamster than of the European hamster so that a larger percentual amount of total inhaled particulate matter reaches the lungs. The European hamster might be a more useful model for the investigation of respiratory tract carcinogenesis due to the possibility of a longer life time exposure and a higher sensitivity to respiratory tract carcinogens

Modified Capillary Cell for Foam Film Studies Allowing Exchange of the Film-Forming Liquidwie

NARCIS (Netherlands)

Wierenga, P.A.; Basheva, E.S.; Denkov, N.D.

2009-01-01

Many of the macroscopic properties of foams and emulsions are controlled by the mesoscopic properties of the thin films separating the bubbles or droplets. The properties of these films depend on contributions (1) from the adsorbed surface layers and (2) from the liquid that separates these adsorbed

Frontier molecular orbitals of a single molecule adsorbed on thin insulating films supported by a metal substrate: electron and hole attachment energies.

Science.gov (United States)

Scivetti, Iván; Persson, Mats

2017-09-06

We present calculations of vertical electron and hole attachment energies to the frontier orbitals of a pentacene molecule absorbed on multi-layer sodium chloride films supported by a copper substrate using a simplified density functional theory (DFT) method. The adsorbate and the film are treated fully within DFT, whereas the metal is treated implicitly by a perfect conductor model. We find that the computed energy gap between the highest and lowest unoccupied molecular orbitals-HOMO and LUMO -from the vertical attachment energies increases with the thickness of the insulating film, in agreement with experiments. This increase of the gap can be rationalised in a simple dielectric model with parameters determined from DFT calculations and is found to be dominated by the image interaction with the metal. We find, however, that this simplified model overestimates the downward shift of the energy gap in the limit of an infinitely thick film.

Development of adsorbents for recovery of uranium from seawater

International Nuclear Information System (INIS)

Egawa, Hiroaki; Furusaki, Shintaro.

1987-01-01

The largest subject for putting the extraction of uranium from seawater in practical use is the development of high performance adsorbents for uranium. In this paper, the way of thinking about the development of adsorbents for extracting uranium from seawater and the recent reports on this subject are described. Next, the research on the adsorbing capacity and adsorbing rate of the adsorbents developed so far is summarized, and the way of thinking about the evaluation of adsorbent performance which is the base of the design of a system for extracting uranium from seawater is explained, taking amidoxime type adsorbent as the example. For Japan where energy resources are scant, the uranium contained in seawater, which is estimated to be about 4.2 billion t, is the most luring important element. Uranium is contained in seawater is very low concentration of 3 ppb, and exists as anion complex salt. In 1960s, the Harwell Atomic Energy Research Establishment in UK found out that titanium oxide hydrate is the most promising as the adsorbent. Also a number of organic absorbents have been developed. In order to bring adsorbents in contact with seawater, pumping, ocean current and wave force are utilized. Adsorbents are in spherical, fiber and film forms, and held as fixed beds and fluidized beds. (Kako, I.) 48 refs

Effect of adsorbed/intercalated anionic dyes into the mechanical properties of PVA: layered zinc hydroxide nitrate nanocomposites.

Science.gov (United States)

Marangoni, Rafael; Mikowski, Alexandre; Wypych, Fernando

2010-11-15

Zinc hydroxide nitrate (ZHN) was adsorbed with anions of blue dyes (Chicago sky blue, CSB; Evans blue, EB; and Niagara blue, NB) and intercalated with anions of orange dyes (Orange G, OG; Orange II, OII; methyl orange, MO). Transparent, homogeneous and colored nanocomposite films were obtained by casting after dispersing the pigments (dye-intercalated/adsorbed into LHSs) into commercial poly(vinyl alcohol) (PVA). The films were characterized by XRD, UV-Vis spectroscopy, and mechanical testing. The mechanical properties of the PVA compounded with the dye-intercalated/adsorbed ZHN were evaluated, and reasonable increases in Young's modulus and ultimate tensile strength were observed, depending on the amount and choice of layered filler. These results demonstrate the possibility of using a new class of layered hydroxide salts intercalated and adsorbed with anionic dyes to prepare multifunctional polymer nanocomposite materials. Copyright © 2010 Elsevier Inc. All rights reserved.

Interactions between adsorbed macromolecules : measurements on emulsions and liquid films

NARCIS (Netherlands)

Vliet, van T.

1977-01-01

The aim of this study was to gain more insight into the factors, determining the inter- and intramolecular interactions between adsorbed macromolecules. To that end several experimental and theoretical approaches were followed, using well-defined systems. It was shown that these

Transporting method for adsorbing tower and the adsorbing tower

International Nuclear Information System (INIS)

Shimokawa, Nobuhiro.

1996-01-01

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.)

Role of Defects and Adsorbed Water Film in Influencing the Electrical, Optical and Catalytic Properties of Transition Metal Oxides

Science.gov (United States)

Wang, Qi

, gallium nitride and zinc oxide. Most TMOs at room temperature are known to be strongly hydrated. We show that an adsorbed water film present on the surface of TMOs facilitates the dissolution of gaseous species and promotes charge transfers at the adsorbed-water/oxide interfaces. Further, we show the role of vacancy defects in enhancing catalytic processes by directly monitoring the charge transfer process between gaseous species and vacancy defects in non-stoichiometric p-type nickel oxide and n-type tungsten oxide using in-situ NIR-PL, electrical resistance, and X-ray photoelectron spectroscopy. We find the importance of adsorbed water and vacancy defects in affecting catalytic, electronic, electrical, and optical changes such as insulator-to-metal transitions and radiative emissions during electrochemical reactions. In addition, we demonstrate that electrochemical surface transfer doping exists in another system, specifically, in gallium nitride, and the presence of this adsorbed water film present on the surface of GaN induces electron transfer from GaN that leads to the formation of an electron depletion region on the surface.

The state of physically adsorbed substances in microporous adsorbents

International Nuclear Information System (INIS)

Fomkin, A.A.

1987-01-01

Xe, Kr, Ar, CF 3 Cl, CH 4 adsorption in NaX microporous zeolite of 0.98 Na 2 OxAl 2 O 3 x2.36SiO 2 x0.02H 2 O is studied. Some properties of adsorbates (density, coefficients of expansion, enthalpy, heat capacity) are determined and discussed. The adsorbate in the microporous adsorbent is shown to be a particular state of a substance. Liniarity of adsorption isosteres and sharp changes during isosteric heat capacity of the adsorbate points to the fact that in microporous adsorbents phase transformations of the second type are possible

Equilibrium helium film in the thick film limit

International Nuclear Information System (INIS)

Klier, J.; Schletterer, F.; Leiderer, P.; Shikin, V.

2003-01-01

For the thickness of a liquid or solid quantum film, like liquid helium or solid hydrogen, there exist still open questions about how the film thickness develops in certain limits. One of these is the thick film limit, i.e., the crossover from the thick film to bulk. We have performed measurements in this range using the surface plasmon resonance technique and an evaporated Ag film deposited on glass as substrate. The thickness of the adsorbed helium film is varied by changing the distance h of the bulk reservoir to the surface of the substrate. In the limiting case, when h > 0, the film thickness approaches about 100 nm following the van der Waals law in the retarded regime. The film thickness and its dependence on h is precisely determined and theoretically modeled. The equilibrium film thickness behaviour is discussed in detail. The agreement between theory and experiment is very good

Neutron Scattering Study of Nitrogen Adsorbed on Basal Plane Oriented Graphite

DEFF Research Database (Denmark)

Kjems, Jørgen; Passell, L.; Taub, H.

1976-01-01

Thermal-neutron scattering has been used to investigate the structure of nitrogen films adsorbed on Grafoil, a basal-plane-oriented graphite. Diffraction scans were made at coverages between 1/3 of a monolayer and 7/4 monolayers over a temperature range from 10 to 90 K. The observed line shapes...

Adsorption of UO2+2 by polyethylene adsorbents with amidoxime, carboxyl, and amidoxime/carboxyl group

International Nuclear Information System (INIS)

Choi, Seong-Ho; Nho, Young Chang

2000-01-01

The polyethylene (PE) adsorbents were prepared by a radiation-induced grafting of acrylonitrile (AN), acrylic acid (AA), and the mixture of AN/AA onto PE film, and by subsequent amidoximation of cyano groups of poly-AN graft chains. With an increase of AA composition in AN/AA monomer mixture, the water uptake of the grafted polyethylene film increased. In AN/AA mixture, the maximum adsorption of UO 2+ 2 was observed in the adsorbent with a ratio of AN/AA (50/50, mol%) in copolymer. The amidoxime, carboxyl, and amidoxime/carboxyl groups onto PE acted as a chelating site for the selected UO 2+ 2 . The complex structure of polyethylene with three functional groups and UO 2+ 2 was confirmed by Fourier Transform Infrared (FTIR) spectroscopy. (author)

Water surface coverage effects on reactivity of plasma oxidized Ti films

International Nuclear Information System (INIS)

Pranevicius, L.; Pranevicius, L.L.; Vilkinis, P.; Baltaragis, S.; Gedvilas, K.

2014-01-01

Highlights: • The reactivity of Ti films immersed in water vapor plasma depends on the surface water coverage. • The adsorbed water monolayers are disintegrated into atomic constituents on the hydrophilic TiO 2 under plasma radiation. • The TiO 2 surface covered by water multilayer loses its ability to split adsorbed water molecules under plasma radiation. - Abstract: The behavior of the adsorbed water on the surface of thin sputter deposited Ti films maintained at room temperature was investigated in dependence on the thickness of the resulting adsorbed water layer, controllably injecting water vapor into plasma. The surface morphology and microstructure were used to characterize the surfaces of plasma treated titanium films. Presented experimental results showed that titanium films immersed in water vapor plasma at pressure of 10–100 Pa promoted the photocatalytic activity of overall water splitting. The surfaces of plasma oxidized titanium covered by an adsorbed hydroxyl-rich island structure water layer and activated by plasma radiation became highly chemically reactive. As water vapor pressure increased up to 300–500 Pa, the formed water multilayer diminished the water oxidation and, consequently, water splitting efficiency decreased. Analysis of the experimental results gave important insights into the role an adsorbed water layer on surface of titanium exposed to water vapor plasma on its chemical activity and plasma activated electrochemical processes, and elucidated the surface reactions that could lead to the split of water molecules

Modeling adsorption: Investigating adsorbate and adsorbent properties

Science.gov (United States)

Webster, Charles Edwin

1999-12-01

Surface catalyzed reactions play a major role in current chemical production technology. Currently, 90% of all chemicals are produced by heterogeneously catalyzed reactions. Most of these catalyzed reactions involve adsorption, concentrating the substrate(s) (the adsorbate) on the surface of the solid (the adsorbent). Pore volumes, accessible surface areas, and the thermodynamics of adsorption are essential in the understanding of solid surface characteristics fundamental to catalyst and adsorbent screening and selection. Molecular properties such as molecular volumes and projected molecular areas are needed in order to convert moles adsorbed to surface volumes and areas. Generally, these molecular properties have been estimated from bulk properties, but many assumptions are required. As a result, different literature values are employed for these essential molecular properties. Calculated molar volumes and excluded molecular areas are determined and tabulated for a variety of molecules. Molecular dimensions of molecules are important in the understanding of molecular exclusion as well as size and shape selectivity, diffusion, and adsorbent selection. Molecular dimensions can also be used in the determination of the effective catalytic pore size of a catalyst. Adsorption isotherms, on zeolites, (crystalline mineral oxides) and amorphous solids, can be analyzed with the Multiple Equilibrium Analysis (MEA) description of adsorption. The MEA produces equilibrium constants (Ki), capacities (ni), and thermodynamic parameters (enthalpies, ΔHi, and entropies, ΔSi) of adsorption for each process. Pore volumes and accessible surface areas are calculated from the process capacities. Adsorption isotherms can also be predicted for existing and new adsorbate-adsorbent systems with the MEA. The results show that MEA has the potential of becoming a standard characterization method for microporous solids that will lead to an increased understanding of their behavior in gas

Tuning Surface Energy Landscapes in Metallic Quantum Films using Alkali Adsorbates

Science.gov (United States)

Khajetoorians, Alexander; Qin, Shengyong; Zhu, Wenguang; Eisele, Holger; Zhang, Zhenyu; Shih, Chih-Kang

2008-03-01

Quantum confinement shows a strong interplay with growth and kinetics in thin metal systems where the Fermi wavelength has a special relationship to the surface normal lattice constant. In the case of Pb/Si(111) systems, this relationship reveals an interesting thickness-dependent bilayer oscillation in the density of states and surface energy up to a phase. In this paper, we report on a novel effect: tuning of the energy landscape of a flat-top quantum Pb mesa using Cs adsorbates. Using STM/STS, we show that depositing Cs adsorbates on a thin Pb mesa promotes quantum stable Pb nanoislands on preferentially unstable thicknesses. Thickness-dependent nanoisland densities show a strong bilayer oscillation correlating with quantum stability. By modifying the Cs coverage on the mesa surface, we can tune the lateral size distribution of the nanoislands and the overall amplitude of the island density oscillation. Nanoisland formation is linked to a step decoration of Cs adatoms along the step edge of the nanoisland.

Comparing dissolved reactive phosphorus measured by DGT with ferrihydrite and titanium dioxide adsorbents

DEFF Research Database (Denmark)

Panther, Jared G.; Teasdale, Peter R.; Bennett, William W.

2011-01-01

Two adsorbents (Metsorb and ferrihydrite) used in binding layers with the diffusive gradients in a thin film technique were evaluated for the measurement of dissolved reactive phosphorous (DRP) in synthetic and natural waters. Possible interferences were investigated with Cl- (up to 1.35molL-1) a...

Microwave plasma induced surface modification of diamond-like carbon films

Science.gov (United States)

Rao Polaki, Shyamala; Kumar, Niranjan; Gopala Krishna, Nanda; Madapu, Kishore; Kamruddin, Mohamed; Dash, Sitaram; Tyagi, Ashok Kumar

2017-12-01

Tailoring the surface of diamond-like carbon (DLC) film is technically relevant for altering the physical and chemical properties, desirable for useful applications. A physically smooth and sp3 dominated DLC film with tetrahedral coordination was prepared by plasma-enhanced chemical vapor deposition technique. The surface of the DLC film was exposed to hydrogen, oxygen and nitrogen plasma for physical and chemical modifications. The surface modification was based on the concept of adsorption-desorption of plasma species and surface entities of films. Energetic chemical species of microwave plasma are adsorbed, leading to desorbtion of the surface carbon atoms due to energy and momentum exchange. The interaction of such reactive species with DLC films enhanced the roughness, surface defects and dangling bonds of carbon atoms. Adsorbed hydrogen, oxygen and nitrogen formed a covalent network while saturating the dangling carbon bonds around the tetrahedral sp3 valency. The modified surface chemical affinity depends upon the charge carriers and electron covalency of the adsorbed atoms. The contact angle of chemically reconstructed surface increases when a water droplet interacts either through hydrogen or van dear Waals bonding. These weak interactions influenced the wetting property of the DLC surface to a great extent.

The molecular mechanism of mediation of adsorbed serum proteins to endothelial cells adhesion and growth on biomaterials.

Science.gov (United States)

Yang, Dayun; Lü, Xiaoying; Hong, Ying; Xi, Tingfei; Zhang, Deyuan

2013-07-01

To explore molecular mechanism of mediation of adsorbed proteins to cell adhesion and growth on biomaterials, this study examined endothelial cell adhesion, morphology and viability on bare and titanium nitride (TiN) coated nickel titanium (NiTi) alloys and chitosan film firstly, and then identified the type and amount of serum proteins adsorbed on the three surfaces by proteomic technology. Subsequently, the mediation role of the identified proteins to cell adhesion and growth was investigated with bioinformatics analyses, and further confirmed by a series of cellular and molecular biological experiments. Results showed that the type and amount of adsorbed serum proteins associated with cell adhesion and growth was obviously higher on the alloys than on the chitosan film, and these proteins mediated endothelial cell adhesion and growth on the alloys via four ways. First, proteins such as adiponectin in the adsorbed protein layer bound with cell surface receptors to generate signal transduction, which activated cell surface integrins through increasing intracellular calcium level. Another way, thrombospondin 1 in the adsorbed protein layer promoted TGF-β signaling pathway activation and enhanced integrins expression. The third, RGD sequence containing proteins such as fibronectin 1, vitronectin and thrombospondin 1 in the adsorbed protein layer bound with activated integrins to activate focal adhesion pathway, increased focal adhesion formation and actin cytoskeleton organization and mediated cell adhesion and spreading. In addition, the activated focal adhesion pathway promoted the expression of cell growth related genes and resulted in cell proliferation. The fourth route, coagulation factor II (F2) and fibronectin 1 in the adsorbed protein layer bound with cell surface F2 receptor and integrin, activated regulation of actin cytoskeleton pathway and regulated actin cytoskeleton organization. Copyright © 2013 Elsevier Ltd. All rights reserved.

IR spectroscopy studies of silver and copper nano-films

Energy Technology Data Exchange (ETDEWEB)

Meng, Fanzhen

2007-01-10

The present work is focused on the infrared optical properties of thin Ag and Cu films grown on MgO(001) and the Surface-Enhanced Infrared Absorption (SEIRA) of CO on these metal films. During both the deposition of the metal films onto MgO(001) and gas exposure to the metal films at low temperatures (<100 K) in Ultra High Vacuum (UHV), infrared spectra were captured in situ in transmission or reflection geometry. Afterwards the surface morphology of the films was examined ex situ by atomic force microscopy (AFM). For the first time, an infrared reflectance minimum was found during the metal film growth. The infrared optical properties of some films can be described by the Drude-type model or the Effective Medium Model. The Ag films show different surface morphologies at different substrate temperatures and at different final thicknesses. Also the SEIRA of CO adsorbed on Ag films is strongly related to the surface morphologies. The Cu films prepared at room temperature show island like surface morphology. SEIRA of CO adsorbed on Cu films shows differences depending on the Cu island size. (orig.)

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

DEFF Research Database (Denmark)

Schnadt, Joachim; Xu, Wei; Vang, Ronnie Thorbjørn

2010-01-01

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...

Relation between film thickness and surface doping of MoS2 based field effect transistors

Science.gov (United States)

Lockhart de la Rosa, César J.; Arutchelvan, Goutham; Leonhardt, Alessandra; Huyghebaert, Cedric; Radu, Iuliana; Heyns, Marc; De Gendt, Stefan

2018-05-01

Ultra-thin MoS2 film doping through surface functionalization with physically adsorbed species is of great interest due to its ability to dope the film without reduction in the carrier mobility. However, there is a need for understanding how the thickness of the MoS2 film is related to the induced surface doping for improved electrical performance. In this work, we report on the relation of MoS2 film thickness with the doping effect induced by the n-dopant adsorbate poly(vinyl-alcohol). Field effect transistors built using MoS2 films of different thicknesses were electrically characterized, and it was observed that the ION/OFF ratio after doping in thin films is more than four orders of magnitudes greater when compared with thick films. Additionally, a semi-classical model tuned with the experimental devices was used to understand the spatial distribution of charge in the channel and explain the observed behavior. From the simulation results, it was revealed that the two-dimensional carrier density induced by the adsorbate is distributed rather uniformly along the complete channel for thin films (<5.2 nm) contrary to what happens for thicker films.

Adsorption of lysozyme to phospholipid and meibomian lipid monolayer films.

Science.gov (United States)

Mudgil, Poonam; Torres, Margaux; Millar, Thomas J

2006-03-15

It is believed that a lipid layer forms the outer layer of the pre-ocular tear film and this layer helps maintain tear film stability by lowering its surface tension. Proteins of the aqueous layer of the tear film (beneath the lipid layer) may also contribute to reducing surface tension by adsorbing to, or penetrating the lipid layer. The purpose of this study was to compare the penetration of lysozyme, a tear protein, into films of meibomian lipids and phospholipids held at different surface pressures to determine if lysozyme were part of the surface layer of the tear film. Films of meibomian lipids or phospholipids were spread onto the surface of a buffered aqueous subphase. Films were compressed to particular pressures and lysozyme was injected into the subphase. Changes in surface pressure were monitored to determine adsorption or penetration of lysozyme into the surface film. Lysozyme penetrated a meibomian lipid film at all pressures tested (max=20 mN/m). It also penetrated phosphatidylglycerol, phosphatidylserine or phosphatidylethanolamine lipid films up to a pressure of 20 mN/m. It was not able to penetrate a phosphatidylcholine film at pressures >or=10 mN/m irrespective of the temperature being at 20 or 37 degrees C. However, it was able to penetrate it at very low pressures (<10 mN/m). Epifluorescence microscopy showed that the protein either adsorbs to or penetrates the lipid layer and the pattern of mixing depended upon the lipid at the surface. These results indicate that lysozyme is present at the surface of the tear film where it contributes to decreasing the surface tension by adsorbing and penetrating the meibomian lipids. Thus it helps to stabilize the tear film.

Structural and shear characteristics of adsorbed sodium caseinate and monoglyceride mixed monolayers at the air-water interface.

Science.gov (United States)

Rodríguez Patino, Juan M; Cejudo Fernández, Marta; Carrera Sánchez, Cecilio; Rodríguez Niño, Ma Rosario

2007-09-01

The structural and shear characteristics of mixed monolayers formed by an adsorbed Na-caseinate film and a spread monoglyceride (monopalmitin or monoolein) on the previously adsorbed protein film have been analyzed. Measurements of the surface pressure (pi)-area (A) isotherm and surface shear viscosity (eta(s)) were obtained at 20 degrees C and at pH 7 in a modified Wilhelmy-type film balance. The structural and shear characteristics of the mixed films depend on the surface pressure and on the composition of the mixed film. At surface pressures lower than the equilibrium surface pressure of Na-caseinate (at picaseinate and monoglyceride coexist at the interface, with a structural polymorphism or a liquid expanded structure due to the presence of monopalmitin or monoolein in the mixture, respectively. At higher surface pressures, collapsed Na-caseinate residues may be displaced from the interface by monoglyceride molecules. For a Na-caseinate-monopalmitin mixed film the eta(s) value varies greatly with the surface pressure (or surface density) of the mixed monolayer at the interface. In general, the greater the surface pressure, the greater are the values of eta(s). However, the values of eta(s) for a Na-caseinate-monoolein mixed monolayer are very low and practically do not depend on the surface pressure. The collapsed Na-caseinate residues displaced from the interface by monoglyceride molecules at pi>pi(e)(CS) have important repercussions on the shear characteristics of the mixed films.

Preconcentration in gas or liquid phases using adsorbent thin films

Directory of Open Access Journals (Sweden)

Antonio Pereira Nascimento Filho

2006-03-01

Full Text Available The possibility of preconcentration on microchannels for organic compounds in gas or liquid phases was evaluated. Microstructures with different geometries were mechanically machined using poly(methyl methacrylate - PMMA as substrates and some cavities were covered with cellulose. The surfaces of the microchannels were modified by plasma deposition of hydrophilic or hydrophobic films using 2-propanol and hexamethyldisilazane (HMDS, respectively. Double layers of HMDS + 2-propanol were also used. Adsorption characterization was made by Quartz Crystal Measurements (QCM technique using reactants in a large polarity range that showed the adsorption ability of the structures depends more on the films used than on the capillary phenomena. Cellulose modified by double layer film showed a high retention capacity for all gaseous compounds tested. However, structures without plasma deposition showed low retention capacity. Microchannels modified with double layers or 2-propanol plasma films showed higher retention than non-modified ones on gas or liquid phase.

Degradation of dimethylformamide on the surface of the nanosized WO{sub 3} films studied by infrared spectroscopy

Energy Technology Data Exchange (ETDEWEB)

Gavrilyuk, A.I., E-mail: gavrilyuk@mail.ioffe.ru

2016-07-30

Highlights: • Dimethylformamide was adsorbed on the surface of the nanosized WO{sub 3} films. • The mechanism of the adsorption was investigated by IR spectroscopy. • The transformations of the adsorbed molecules either in dark or under the action of light was discussed. - Abstract: Here I report on the degradation of dimethylformamide on the surface of the nanosized WO{sub 3} films under the action of light. Dimethylformamide, a substance that has a series of interesting properties, was adsorbed on the surface of the WO{sub 3} films and its adsorption mechanism and transformations under the action of light have been investigated with the help of the IR spectroscopy. The spirit of the research is that both DMF modifications have been used i.e., conventional and that with the substitution of hydrogen atoms by deuterium. Formation of two weak bonds (donor-acceptor bond and hydrogen bond) provides a great catalytic effect for photo-initiated proton-coupled electron transfer from the adsorbed molecules to the WO{sub 3} film surface. The mechanism of the detachment of hydrogen atoms and subsequent transformation of the adsorbed molecules has been investigated and discussed.

Adsorption of apo- and holo-tear lipocalin to a bovine Meibomian lipid film.

Science.gov (United States)

Mudgil, Poonam; Millar, Thomas J

2008-04-01

Adsorption of apo- and holo-tear lipocalin (Tlc) to bovine Meibomian lipid film was studied. A Langmuir trough was used for these studies and the adsorption of protein was observed by recording changes in the pressure with time (pi-T profile). The films were photographed at different stages of adsorption by doping Meibomian lipids with a fluorescently tagged lipid. The results indicated that apo-Tlc adsorbed much more quickly than holo-Tlc to the Meibomian lipid film. Contrary to the expectation that holo-Tlc would release lipids to the surface and surface pressure would be higher, it was found that the surface pressure was higher with the adsorption of apo-Tlc to the surface. Photography of the films showed that apo- and holo-Tlc interacted differently with the Meibomian lipid layer. Adsorption of holo-Tlc resulted in big bright patches and adsorption of apo-Tlc resulted in many small patches along with the big patches. Both forms of Tlc produced a more stable film as indicated by decreased movement of the protein adsorbed films, and a higher maximum surface pressure upon compression of these films compared with Meibomian lipid films alone. Isocyles of apo-Tlc adsorbed films gave a higher surface pressure than that of holo-Tlc. From these results, it is concluded that both apo- and holo-Tlc adsorbed to the Meibomian lipid layer and the delivery of the lipids from Tlc to the outer lipid layer could not be detected by our techniques. Its scavenging role to remove lipids from the corneal surface and bind with them might be beneficial for increasing tear viscosity but whether those lipids are delivered to the outermost lipid layer still remains unclear.

Headgroup effects of template monolayers on the adsorption behavior and conformation of glucose oxidase adsorbed at air/liquid interfaces.

Science.gov (United States)

Wang, Ke-Hsuan; Syu, Mei-Jywan; Chang, Chien-Hsiang; Lee, Yuh-Lang

2011-06-21

Stearic acid (SA) and octadecylamine (ODA) monolayers at the air/liquid interface were used as template layers to adsorb glucose oxidase (GOx) from aqueous solution. The effect of the template monolayers on the adsorption behavior of GOx was studied in terms of the variation of surface pressure, the evolution of surface morphology observed by BAM and AFM, and the conformation of adsorbed GOx. The results show that the presence of a template monolayer can enhance the adsorption rate of GOx; furthermore, ODA has a higher ability, compared to SA, to adsorb GOx, which is attributed to the electrostatic attractive interaction between ODA and GOx. For adsorption performed on a bare surface or on an SA monolayer, the surface pressure approaches an equilibrium value (ca. 8 mN/m) after 2 to 3 h of adsorption and remains nearly constant in the following adsorption process. For the adsorption on an ODA monolayer, the surface pressure will increase further 1 to 2 h after approaching the first equilibrium pressure, which is termed the second adsorption stage. The measurement of circular dichroism (CD) spectroscopy indicates that the Langmuir-Blodgett films of adsorbed GOx transferred at the first equilibrium state (π = 8 mN/m) have mainly a β-sheet conformation, which is independent of the type of template monolayers. However, the ODA/GOx LB film transferred at the second adsorption stage has mainly an α-helix conformation. It is concluded that the specific interaction between ODA and GOx not only leads to a higher adsorption rate and adsorbed amount of GOx but also induces a conformation change in adsorbed GOx from β-sheet to α-helix. The present results indicate that is possible to control the conformation of adsorbed protein by selecting the appropriate template monolayer. © 2011 American Chemical Society

Infrared Analysis Of Enzymes Adsorbed Onto Model Surfaces

Science.gov (United States)

Story, Gloria M.; Rauch, Deborah S.; Brode, Philip F.; Marcott, Curtis A.

1989-12-01

The adsorption of the enzymes, subtilisin BPN' and lysozyme, onto model surfaces was examined using attenuated total reflectance (ATR) infrared (IR) spectroscopy. Using a cylindrical internal reflection (CIRcle) cell with a Germanium (Ge) internal reflection element (IRE), model hydrophilic surfaces were made by plasma cleaning the IRE and model hydrophobic surfaces were made by precoating the IRE with a thin film of polystyrene. Gas chromatography (GC)-IR data collection software was used to monitor adsorption kinetics during the first five minutes after injection of the enzyme into the CIRcle cell. It was found that for both lysozyme and BPN', most of the enzyme that was going to adsorb onto the model surface did so within ten seconds after injection. Nearly an order-of-magnitude more BPN' adsorbed on the hydrophobic Ge surface than the hydrophilic one, while lysozyme adsorbed somewhat more strongly to the hydrophilic Ge surface. Overnight, the lysozyme layer continued to increase in thickness, while BPN' maintained its initial coverage. The appearance of carboxylate bands in some of the adsorbed BPN' spectra suggests the occurrence of peptide bond hydrolysis. A Au/Pd coating on the CIRcle cell o-rings had a significant effect on the adsorption of BPN'. (This coating was applied in an attempt to eliminate interfering Teflon absorption bands.) An apparent electrochemical reaction occurred, involving BPN', Ge, Au/Pd, and the salt solution used to stabilize BPN'. The result of this reaction was enhanced adsorption of the enzyme around the coated o-rings, etching of the Ge IRE at the o-ring site, and some autolysis of the enzyme. No such reaction was observed with lysozyme.

Instability of confined water films between elastic surfaces

NARCIS (Netherlands)

de Beer, Sissi; 't Mannetje, Dieter; Zantema, Sietske; Mugele, Friedrich

2010-01-01

We investigated the dynamics of nanometer thin water films at controlled ambient humidity adsorbed onto two atomically smooth mica sheets upon rapidly bringing the surfaces into contact. Using a surface forces apparatus (SFA) in imaging mode, we found that the water films break up into a

Organized organic ultrathin films fundamentals and applications

CERN Document Server

Ariga, Katsuhiko

2012-01-01

This handy reference is the first comprehensive book covering both fundamentals and recent developments in the field with an emphasis on nanotechnology. Written by a highly regarded author in the field, the book details state-of-the-art preparation, characterization and applications of thin films of organic molecules and biomaterials fabricated by wet processes and also highlights applications in nanotechnology The categories of films covered include monomolecular films (monolayers) both on a water surface and on a solid plate, Langmuir-Blodgett films (transferred multilayer films on a solid plate from a water surface), layer-by-layer films (adsorbed multilayer films on a solid support), and spontaneously assembled films in solution.

Hydrodynamic thickness of petroleum oil adsorbed layers in the pores of reservoir rocks.

Science.gov (United States)

Alkafeef, Saad F; Algharaib, Meshal K; Alajmi, Abdullah F

2006-06-01

The hydrodynamic thickness delta of adsorbed petroleum (crude) oil layers into the pores of sandstone rocks, through which the liquid flows, has been studied by Poiseuille's flow law and the evolution of (electrical) streaming current. The adsorption of petroleum oil is accompanied by a numerical reduction in the (negative) surface potential of the pore walls, eventually stabilizing at a small positive potential, attributed to the oil macromolecules themselves. After increasing to around 30% of the pore radius, the adsorbed layer thickness delta stopped growing either with time or with concentrations of asphaltene in the flowing liquid. The adsorption thickness is confirmed with the blockage value of the rock pores' area determined by the combination of streaming current and streaming potential measurements. This behavior is attributed to the effect on the disjoining pressure across the adsorbed layer, as described by Derjaguin and Churaev, of which the polymolecular adsorption films lose their stability long before their thickness has approached the radius of the rock pore.

Nanocellulose-Zeolite Composite Films for Odor Elimination.

Science.gov (United States)

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

2015-07-08

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

Adsorbed Polymer Nanolayers on Solids: Mechanism, Structure and Applications

Science.gov (United States)

Sen, Mani Kuntal

In this thesis, by combining various advanced x-ray scattering, spectroscopic and other surface sensitive characterization techniques, I report the equilibrium polymer chain conformations, structures, dynamics and properties of polymeric materials at the solid-polymer melt interfaces. Following the introduction, in chapter 2, I highlight that the backbone chains (constituted of CH and CH2 groups) of the flattened polystyrene (PS) chains preferentially orient normal to the weakly interactive substrate surface via thermal annealing regardless of the initial chain conformations, while the orientation of the phenyl rings becomes randomized, thereby increasing the number of surface-segmental contacts (i.e., enthalpic gain) which is the driving force for the flattening process of the polymer chains even onto a weakly interactive solid. In chapter 3, I elucidate the flattened structures in block copolymer (BCP) thin films where both blocks lie flat on the substrate, forming a 2D randomly phase-separated structure irrespective of their microdomain structures and interfacial energetics. In chapter 4, I reveal the presence of an irreversibly adsorbed BCP layer which showed suppressed dynamics even at temperatures far above the individual glass transition temperatures of the blocks. Furthermore, this adsorbed BCP layer plays a crucial role in controlling the microdomain orientation in the entire film. In chapter 5, I report a radically new paradigm of designing a polymeric coating layer of a few nanometers thick ("polymer nanolayer") with anti-biofouling properties.

Isotherms of Capillary Condensation Influenced by Formation of Adsorption Films.

Science.gov (United States)

Churaev; Starke; Adolphs

2000-01-15

Isotherms of capillary condensation are often used to determine the vapor sorption capacity of porous adsorbents as well as the pore size distribution by radii. In this paper, for calculating the volume of capillary condensate and of adsorption films in a porous body, an approach based on the theory of surface forces is used. Adsorption isotherms and disjoining pressure isotherms of wetting films are presented here in an exponential form discussed earlier. The calculations were made for straight cylindrical capillaries of different radii and slit pores of different width. The mechanisms of capillary condensation differ in cylindrical and slit pores. In cylindrical pores capillary condensation occurs due to capillary instability of curved wetting films on a capillary surface, when film thickness grows. In the case of slit pores, coalescence of wetting films formed on opposite slit surfaces proceeds under the action of attractive dispersion forces. Partial volumes of liquid in the state of both capillary condensate and adsorbed films are calculated dependent on the relative vapor pressure in a surrounding media. Copyright 2000 Academic Press.

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

Energy Technology Data Exchange (ETDEWEB)

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

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.

Neutron scattering study of ³⁶ Ar monolayer films adsorbed on graphite

DEFF Research Database (Denmark)

Taub, H.; da Costa Carneiro, Kim; Kjems, Jørgen

1977-01-01

Diffraction of neutrons from 36 Ar monolayers adsorbed on graphite basal planes indicates that an ordered, two-dimensional (2D) triangular lattice is formed at low temperature. The lattice constant is found to be slightly larger than that of the bulk 3D solid but significantly smaller than that o...

Formation Process of Eosin Y-Adsorbing ZnO Particles by Electroless Deposition and Their Photoelectric Conversion Properties.

Science.gov (United States)

Nagaya, Satoshi; Nishikiori, Hiromasa; Mizusaki, Hideaki; Wagata, Hajime; Teshima, Katsuya

2015-06-03

The thin films consisting of crystalline ZnO particles were prepared on fluorine-doped tin oxide electrodes by electroless deposition. The particles were deposited from an aqueous solution containing zinc nitrate, dimethyamine-borane, and eosin Y at 328 K. As the Pd particles were adsorbed on the substrate, not only the eosin Y monomer but also the dimer and debrominated species were rapidly adsorbed on the spherical ZnO particles, which were aggregated and formed secondary particles. On the other hand, in the absence of the Pd particles, the monomer was adsorbed on the flake-shaped ZnO particles, which vertically grew on the substrate surface and had a high crystallinity. The photoelectric conversion efficiency was higher for the ZnO electrodes containing a higher amount of the monomer during light irradiation.

Orientational epitaxy in adsorbed monolayers

International Nuclear Information System (INIS)

Novaco, A.D.; McTague, J.P.

1977-01-01

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

Separative analyses of a chromatographic column packed with a core-shell adsorbent for lithium isotope separation

International Nuclear Information System (INIS)

Sugiyama, T.; Sugura, K.; Enokida, Y.; Yamamoto, I.

2015-01-01

Lithium-6 is used as a blanket material for sufficient tritium production in DT fueled fusion reactors. A core-shell type adsorbent was proposed for lithium isotope separation by chromatography. The mass transfer model in a chromatographic column consisted of 4 steps, such as convection and dispersion in the column, transfer through liquid films, intra-particle diffusion and and adsorption or desorption at the local adsorption sites. A model was developed and concentration profiles and time variation in the column were numerically simulated. It became clear that core-shell type adsorbents with thin porous shell were saturated rapidly relatively to fully porous one and established a sharp edge of adsorption band. This is very important feature because lithium isotope separation requires long-distance development of adsorption band. The values of HETP (Height Equivalent of a Theoretical Plate) for core-shell adsorbent packed column were estimated by statistical moments of the step response curve. The value of HETP decreased with the thickness of the porous shell. A core-shell type adsorbent is, then, useful for lithium isotope separation. (authors)

In-plane conductance of thin films as a probe of surface chemical environment: Adsorbate effects on film electronic properties of indium tin oxide and gold

Science.gov (United States)

Swint, Amy Lynn

Changes in the in-plane conductance of conductive thin films are observed as a result of chemical adsorption at the surface. Reaction of the indium tin oxide (ITO) surface with Bronsted acids (bases) leads to increases (decreases) in its in-plane conductance as measured by a four-point probe configuration. The conductance varies monotonically with pH suggesting that the degree of surface protonation or hydroxylation controls the surface charge density, which in turn affects the width of the n-type depletion layer, and ultimately the in-plane conductance. Measurements at constant pH with a series of tetraalkylammonium hydroxide species of varying cation size indicate that surface dipoles also affect ITO conductance by modulating the magnitude of the surface polarization. Modulating the double layer with varying aqueous salt solutions also affects ITO conductance, though not to the same degree as strong Bronsted acids and bases. Solvents of varying dielectric constant and proton donating ability (ethanol, dimethylformamide) decrease ITO conductance relative to H2O. In addition, changing solvent gives rise to thermally-derived conductance transients, which result from exothermic solvent mixing. The self-assembly of alkanethiols at the surface increases the conductance of ITO films, most likely through carrier population effects. In all cases examined the combined effects of surface charge, adsorbed dipole layer magnitude and carrier injection are responsible for altering the ITO conductance. Besides being directly applicable to the control of electronic properties, these results also point to the use of four-point probe resistance measurements in condensed phase sensing applications. Ultrasensitive conductance-based gas phase sensing of organothiol adsorption to gold nanowires is accomplished with a limit of detection in the 105 molecule range. Further refinement of the inherently low noise resistance measurement may lead to observation of single adsorption events at

Thickness and structure of the water film deposited from vapour on calcite surfaces

DEFF Research Database (Denmark)

Bohr, Jakob; Wogelius, Roy A.; Morris, Peter M.

2010-01-01

Synchrotron X-ray reflectivity (SXR) was used to measure the thickness of the water film that adsorbs on a {10¯14} cleavage surface of calcite (CaCO3) in a sample chamber where relative humidity could be controlled within the range from......Synchrotron X-ray reflectivity (SXR) was used to measure the thickness of the water film that adsorbs on a {10¯14} cleavage surface of calcite (CaCO3) in a sample chamber where relative humidity could be controlled within the range from...

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

International Nuclear Information System (INIS)

Koske, P.H.; Ohlrogge, K.

1984-01-01

For the production of 1 kg uranium from seawater about 10 9 kg seawater - depending on the extraction efficiency - have to be processed in a production plant. Such high seawater flows have to be put through adsorber beds the area of which depends on the flow velocity of the water in the bed. For a typical polyamidoxim (PAO) adsorber granulate with a grain size distribution of 0.3 to 1.2 mm the velocity in a fluidized bed is limited to about 1 cm/s in order to prevent carry out of the adsorber material. The consequences of this rather low bed velocity are large and expensive bed areas for technical production plants. 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 water before this is leaving the adsorption unit. This concept enables considerably higher seawater velocities thus reducing the bed area. Theoretical considerations are presented together with experimental results from field tests. (author)

Electrochemical, atomic force microscopy and infrared reflection absorption spectroscopy studies of pre-formed mussel adhesive protein films on carbon steel for corrosion protection

Energy Technology Data Exchange (ETDEWEB)

Zhang, Fan, E-mail: fanzhang@kth.se [KTH Royal Institute of Technology, School of Chemical Science and Engineering, Department of Chemistry, Div. of Surface and Corrosion Science, Drottning Kristinas vaeg.51, SE-100 44 Stockholm (Sweden); Pan, Jinshan [KTH Royal Institute of Technology, School of Chemical Science and Engineering, Department of Chemistry, Div. of Surface and Corrosion Science, Drottning Kristinas vaeg.51, SE-100 44 Stockholm (Sweden); Claesson, Per Martin [KTH Royal Institute of Technology, School of Chemical Science and Engineering, Department of Chemistry, Div. of Surface and Corrosion Science, Drottning Kristinas vaeg.51, SE-100 44 Stockholm (Sweden); Institute for Surface Chemistry, P.O. Box 5607, SE-114 86 Stockholm (Sweden); Brinck, Tore [KTH Royal Institute of Technology, School of Chemical Science and Engineering, Department of Physical Chemistry, Division of Physical Chemistry, Teknikringen 36, SE-10044 Stockholm (Sweden)

2012-10-01

Electrochemical measurements, in situ and ex situ atomic force microscopy (AFM) experiments and infrared reflection absorption spectroscopy (IRAS) analysis were performed to investigate the formation and stability as well as corrosion protection properties of mussel adhesive protein (Mefp-1) films on carbon steel, and the influence of cross-linking by NaIO{sub 4} oxidation. The in situ AFM measurements show flake-like adsorbed protein aggregates in the film formed at pH 9. The ex situ AFM images indicate multilayer-like films and that the film becomes more compact and stable in NaCl solution after the cross-linking. The IRAS results reveal the absorption bands of Mefp-1 on carbon steel before and after NaIO{sub 4} induced oxidation of the pre-adsorbed protein. Within a short exposure time, a certain corrosion protection effect was noted for the pre-formed Mefp-1 film in 0.1 M NaCl solution. Cross-linking the pre-adsorbed film by NaIO{sub 4} oxidation significantly enhanced the protection efficiency by up to 80%. - Highlights: Black-Right-Pointing-Pointer Mussel protein was tested as 'green' corrosion protection strategy for steel. Black-Right-Pointing-Pointer At pH 9, the protein adsorbs on carbon steel and forms a multilayer-like film. Black-Right-Pointing-Pointer NaIO{sub 4} leads to structural changes and cross-linking of the protein film. Black-Right-Pointing-Pointer Cross-linking results in a dense and compact film with increased stability. Black-Right-Pointing-Pointer Cross-linking of preformed film significantly enhances the corrosion protection.

Gas Sensing Properties of Pure and Cr Activated WO3 Thick Film Resistors

Directory of Open Access Journals (Sweden)

V. B. GAIKWAD

2010-09-01

Full Text Available Thick films of WO3 (Tungsten Oxide were prepared by screen-printing techniques. The surfaces of the films were modified by dipping them into an aqueous solution of Chromium Oxide (CrO3 for different intervals of time, followed by firing at 550 oC for 30 min. The gas sensing performance of the pure and Cr2O3-modified films was tested for various gases at different temperatures. The unmodified films showed response to H2S, ethanol and cigar smoke. However Cr2O3- modified films suppresses gas sensing response to all gases except H2S. The surface modification, using dipping process, altered the adsorbate-adsorbent interactions, which gave the specific selectivity and enhanced sensitivity to H2S gas. The gas response, selectivity, thermal stability and recovery time of the sensor were measured and presented. The role played by surface chromium species to improve gas sensing performance is discussed.

Human serum albumin (HSA) adsorption onto a-SiC:H thin films deposited by hot wire chemical vapor deposition

International Nuclear Information System (INIS)

Swain, Bibhu P.

2006-01-01

In the present paper, we report the study of the adsorption behavior of human serum albumin (HSA) onto surfaces of a-SiC:H thin films deposited by using the hot wire chemical vapor deposition (HWCVD) technique. The surface composition and surface energy of the various substrates as well as the evaluation of the adsorbed amount of protein has been carried out by means of X-ray photoelectron spectroscopy (XPS), Fourier transform infra-red (FTIR) spectroscopy, AFM and contact angle measurements. At the immediate effect of HSA interaction with a-SiC:H films N is adsorbed on the surface and stabilized after 3 days. Preliminary observation found that Si and O atom are desorbed from the surface while C and N set adsorbed to the surface of the a-SiC:H film

Human serum albumin (HSA) adsorption onto a-SiC:H thin films deposited by hot wire chemical vapor deposition

Energy Technology Data Exchange (ETDEWEB)

Swain, Bibhu P. [Department of Metallurgical Engineering and Materials Science, Indian Institute of Technology, Bombay (India) and Samtel Centre for Display Technologies, Indian Institute of Technology Kanpur, India, Kanpur 208016 (India)]. E-mail: bibhup@iitb.ac.in

2006-12-15

In the present paper, we report the study of the adsorption behavior of human serum albumin (HSA) onto surfaces of a-SiC:H thin films deposited by using the hot wire chemical vapor deposition (HWCVD) technique. The surface composition and surface energy of the various substrates as well as the evaluation of the adsorbed amount of protein has been carried out by means of X-ray photoelectron spectroscopy (XPS), Fourier transform infra-red (FTIR) spectroscopy, AFM and contact angle measurements. At the immediate effect of HSA interaction with a-SiC:H films N is adsorbed on the surface and stabilized after 3 days. Preliminary observation found that Si and O atom are desorbed from the surface while C and N set adsorbed to the surface of the a-SiC:H film.

Selective Hg(II) adsorption from aqueous solutions of Hg(II) and Pb(II) by hydrolyzed acrylamide-grafted PET films.

Science.gov (United States)

Rahman, Nazia; Sato, Nobuhiro; Sugiyama, Masaaki; Hidaka, Yoshiki; Okabe, Hirotaka; Hara, Kazuhiro

2014-01-01

Selective Hg(II) adsorption from aqueous solutions of Hg(II) and Pb(II) using hydrolyzed acrylamide (AAm)-grafted polyethylene terephthalate (PET) films was examined to explore the potential reuse of waste PET materials. Selective recovery of Hg(II) from a mixture of soft acids with similar structure, such as Hg(II) and Pb(II), is important to allow the reuse of recovered Hg(II). An adsorbent for selective Hg(II) adsorption was prepared by γ-ray-induced grafting of AAm onto PET films followed by partial hydrolysis through KOH treatment. The adsorption capacity of the AAm-grafted PET films for Hg(II) ions increased from 15 to 70 mg/g after partial hydrolysis because of the reduction of hydrogen bonding between -CONH2 groups and the corresponding improved access of metal ions to the amide groups. The prepared adsorbent was characterized by Fourier transform infrared spectroscopy and scanning electron microscopy. The absorbent film showed high selectivity for the adsorption of Hg(II) over Pb(II) throughout the entire initial metal concentration range (100-500 mg/L) and pH range (2.2-5.6) studied. The high selectivity is attributed to the ability of Hg(II) ions to form covalent bonds with the amide groups. The calculated selectivity coefficient for the adsorbent binding Hg(II) over Pb(II) was 19.2 at pH 4.5 with an initial metal concentration of 100 mg/L. Selective Hg(II) adsorption equilibrium data followed the Langmuir model and kinetic data were well fitted by a pseudo-second-order equation. The adsorbed Hg(II) and Pb(II) ions were effectively desorbed from the adsorbent film by acid treatment, and the regenerated film showed no marked loss of adsorption capacity upon reuse for selective Hg(II) adsorption.

Improvement of the adhesion strength between copper plated layer and resin substrate using a chemically adsorbed monolayer

Directory of Open Access Journals (Sweden)

Tsuchiya K.

2013-08-01

Full Text Available With reducing the size and weight of electric devices, high-tensile, light and fine copper wire is demanded. So the production technique of a copper wire plated on a super fiber resin (Vectran film was researched for improving the adhesion strength between the copper and the resin. In this study, we used the Cu2+ or Pd2+ complex prepared with a chemically adsorbed monolayer (CAM to improve the adhesion strength between the copper plated layer and the Vectran film. As the result of scotch tape test, it was observed that the adhesion strength between the copper plated layer and Vectran film was improved by the Cu2+ or Pd2+ complex CAM.

Analysis of the electrodeposition and surface chemistry of CdTe, CdSe, and CdS thin films through substrate-overlayer surface-enhanced Raman spectroscopy.

Science.gov (United States)

Gu, Junsi; Fahrenkrug, Eli; Maldonado, Stephen

2014-09-02

The substrate-overlayer approach has been used to acquire surface enhanced Raman spectra (SERS) during and after electrochemical atomic layer deposition (ECALD) of CdSe, CdTe, and CdS thin films. The collected data suggest that SERS measurements performed with off-resonance (i.e. far from the surface plasmonic wavelength of the underlying SERS substrate) laser excitation do not introduce perturbations to the ECALD processes. Spectra acquired in this way afford rapid insight on the quality of the semiconductor film during the course of an ECALD process. For example, SERS data are used to highlight ECALD conditions that yield crystalline CdSe and CdS films. In contrast, SERS measurements with short wavelength laser excitation show evidence of photoelectrochemical effects that were not germane to the intended ECALD process. Using the semiconductor films prepared by ECALD, the substrate-overlayer SERS approach also affords analysis of semiconductor surface adsorbates. Specifically, Raman spectra of benzenethiol adsorbed onto CdSe, CdTe, and CdS films are detailed. Spectral shifts in the vibronic features of adsorbate bonding suggest subtle differences in substrate-adsorbate interactions, highlighting the sensitivity of this methodology.

Controlled surface chemistry of diamond/β-SiC composite films for preferential protein adsorption.

Science.gov (United States)

Wang, Tao; Handschuh-Wang, Stephan; Yang, Yang; Zhuang, Hao; Schlemper, Christoph; Wesner, Daniel; Schönherr, Holger; Zhang, Wenjun; Jiang, Xin

2014-02-04

Diamond and SiC both process extraordinary biocompatible, electronic, and chemical properties. A combination of diamond and SiC may lead to highly stable materials, e.g., for implants or biosensors with excellent sensing properties. Here we report on the controllable surface chemistry of diamond/β-SiC composite films and its effect on protein adsorption. For systematic and high-throughput investigations, novel diamond/β-SiC composite films with gradient composition have been synthesized using the hot filament chemical vapor deposition (HFCVD) technique. As revealed by scanning electron microscopy (SEM), the diamond/β-SiC ratio of the composite films shows a continuous change from pure diamond to β-SiC over a length of ∼ 10 mm on the surface. X-ray photoelectron spectroscopy (XPS) and time-of-flight secondary ion mass spectrometry (ToF-SIMS) was employed to unveil the surface termination of chemically oxidized and hydrogen treated surfaces. The surface chemistry of the composite films was found to depend on diamond/β-SiC ratio and the surface treatment. As observed by confocal fluorescence microscopy, albumin and fibrinogen were preferentially adsorbed from buffer: after surface oxidation, the proteins preferred to adsorb on diamond rather than on β-SiC, resulting in an increasing amount of proteins adsorbed to the gradient surfaces with increasing diamond/β-SiC ratio. By contrast, for hydrogen-treated surfaces, the proteins preferentially adsorbed on β-SiC, leading to a decreasing amount of albumin adsorbed on the gradient surfaces with increasing diamond/β-SiC ratio. The mechanism of preferential protein adsorption is discussed by considering the hydrogen bonding of the water self-association network to OH-terminated surfaces and the change of the polar surface energy component, which was determined according to the van Oss method. These results suggest that the diamond/β-SiC gradient film can be a promising material for biomedical applications which

Modification of H2O adsorbed Si(100)-(2 x 1) surface by photon and electron beam

International Nuclear Information System (INIS)

Moon, S.W.; Chung, S.M.; Hwang, C.C.; Ihm, K.W.; Kang, T.-H.; Chen, C.H.; Park, C.-Y.

2004-01-01

Full text: Oxidation of silicon has been the subject of intense scientific and technological interest due to the several uses of thin oxide films as insulating layers in microelectronic devices. The great strides have been made in understanding about the formation and thermal evolution of the Si/SiO 2 interface. In this presentation, we provide synchrotron radiation photoemission spectroscopy (SRPES) and photoemission electron microscope (PEEM) results, showing how a H 2 O adsorbed Si(100) surface evolves into an ultra-thin silicon oxide m when exposed to monochromatized synchrotron radiation and electron beam at room temperature. All SRPES, PEEM experiments have been performed at the beam line, 4B1, of Pohang Light Source (PLS) in Korea. Water dissociates into OH(a) and H(a) species upon adsorption on the Si(100)-(2 - 1) at room temperature. The bonding (b 2 ) and antibonding (a 1 ) OH orbital and the oxygen lone pair orbital (b 1 ) from the dissociated OH and H species has been identified in ultraviolet photoemission spectra (UPS). These structures gradually changed and a new silicon oxide peak appeared with the photon/E-beam irradiation. This indicates that the H 2 O adsorbed on Si surface transforms into a thin silicon oxide film by photon/E-beam irradiation. We have shown in our PEEM images that one can make micro-patterns on silicon surface by using the photon induced surface modification. The fabricated patterns can be clearly identified through the inverse contrast images between photon exposed region and unexposed one. The near edge x-ray absorption fine structure (NEXAFS) results revealed that the OH adsorbed Si surface transforms into a thin silicon oxide film by photon irradiation

Positronium chemistry in porous adsorbents

International Nuclear Information System (INIS)

Foti, G.; Nagy, L.G.; Moravcsik, G.; Schay, G.

1981-01-01

Kinetic studies on the annihilation of orthopositronium in porous adsorbents have been performed using lifetime spectroscopy. The positron source applied was 22 Na 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)

Ecological applications of the irradiated adsorbents

International Nuclear Information System (INIS)

Tusseyev, T.

2004-01-01

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.γ) - radiation, α-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

Iodine removal adsorbent histories, aging and regeneration

International Nuclear Information System (INIS)

Hunt, J.R.; Rankovic, L.; Lubbers, R.; Kovach, J.L.

1976-01-01

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

Interaction of hydrogen and oxygen with continuous or granular films of palladium

Energy Technology Data Exchange (ETDEWEB)

Mikhalenko, I.I.; Prokopov, A.M.; Yagodovskii, V.D.

1986-03-01

The authors use desorption and conductometric methods in establishing the existence of three species of adsorbed hydrogen on continuous Pd films and two species on Pd films with a granular structure. Preoxidation of the surface of the continuous films does not affect the rate or kinetic order of hydrogen sorption; oxidation/reduction treatment changes these parameters, but the magnitude of Edes of hydrogen remains unchanged.

Theoretical Insight of Physical Adsorption for a Single-Component Adsorbent + Adsorbate System: I. Thermodynamic Property Surfaces

KAUST Repository

Chakraborty, Anutosh

2009-02-17

Thermodynamic property surfaces for a single-component adsorbent + adsorbate system are derived and developed from the viewpoint of classical thermodynamics, thermodynamic requirements of chemical equilibrium, Gibbs law, and Maxwell relations. They enable us to compute the entropy and enthalpy of the adsorbed phase, the isosteric heat of adsorption, specific heat capacity, and the adsorbed phase volume thoroughly. These equations are very simple and easy to handle for calculating the energetic performances of any adsorption system. We have shown here that the derived thermodynamic formulations fill up the information gap with respect to the state of adsorbed phase to dispel the confusion as to what is the actual state of the adsorbed phase. We have also discussed and established the temperature-entropy diagrams of (i) CaCl 2-in-silica gel + water system for cooling applications, and (ii) activated carbon (Maxsorb III) + methane system for gas storage. © Copyright 2009 American Chemical Society.

Controlled enzymatic cutting of DNA molecules adsorbed on surfaces using soft lithography

Science.gov (United States)

Auerbach, Alyssa; Budassi, Julia; Shea, Emily; Zhu, Ke; Sokolov, Jonathan

2013-03-01

The enzyme DNase I was applied to adsorbed and aligned DNA molecules (Lamda, 48.5 kilobase pairs (kbp), and T4, 165.6 kbp), stretched linearly on a surface, by stamping with a polydimethylsiloxane (PDMS) grating. The DNAs were cut by the enzyme into separated, micron-sized segments along the length of the molecules at positions determined by the grating dimensions (3-20 microns). Ozone-treated PDMS stamps were coated with DNase I solutions and placed in contact with surface-adsorbed DNA molecules deposited on a 750 polymethylmethacrylate (PMMA) film spun-cast onto a silicon substrate. The stamps were applied under pressure for times up to 15 minutes at 37 C. The cutting was observed by fluorescence microscopy imaging of DNA labeled with YOYO dye. Cutting was found to be efficient despite the steric hindrance due to surface attachment of the molecules. Methods for detaching and separating the cut segments for sequencing applications will be discussed. Supported by NSF-DMR program.

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

Energy Technology Data Exchange (ETDEWEB)

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

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.

Study of fine films nature on the surface of copper band by photoelectron spectroscopy method

International Nuclear Information System (INIS)

Reznichenko, K.N.; Fedorov, V.N.; Shevakin, Yu.F.

1983-01-01

The composition of surface films formed on the copper band of industrial production under atmospheric conditions, its changes in thickness and determination of chemical state of the above films are studied. It has been found by the methods of X-ray photoelectronic and Auger-spectroscopy that defect formations on the surface of the copper band of industrial production represent copper oxides in the form of fine films, their change in colour from blue to dark blue probably is determined by different thickness of these defects. The said films on copper have practically identical chemical composition characterized by the presence of unequally valent copper, oxygen in various states (adsorbed and in the form of oxides), carbon and iron. By means of chemical shifts of the line Cu 2psub(3/2) and Ol s the presence in the external part of the film of CuO copper oxide is established and nearer to the interface surface film-metal-of Cu 2 O cuprous oxide which indicates a two-layer surface film structure. The presence of adsorbed carbon and iron in the film composition is a result of surface contamination

High performance Mo adsorbent PZC

Energy Technology Data Exchange (ETDEWEB)

Anon,

1998-10-01

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)

Theoretical Insight of Physical Adsorption for a Single Component Adsorbent + Adsorbate System: II. The Henry Region

KAUST Repository

Chakraborty, Anutosh

2009-07-07

The Henry coefficients of a single component adsorbent + adsorbate system are calculated from experimentally measured adsorption isotherm data, from which the heat of adsorption at zero coverage is evaluated. The first part of the papers relates to the development of thermodynamic property surfaces for a single-component adsorbent + adsorbate system1 (Chakraborty, A.; Saha, B. B.; Ng, K. C.; Koyama, S.; Srinivasan, K. Langmuir 2009, 25, 2204). A thermodynamic framework is presented to capture the relationship between the specific surface area (Ai) and the energy factor, and the surface structural and the surface energy heterogeneity distribution factors are analyzed. Using the outlined approach, the maximum possible amount of adsorbate uptake has been evaluated and compared with experimental data. It is found that the adsorbents with higher specific surface areas tend to possess lower heat of adsorption (ΔH°) at the Henry regime. In this paper, we have established the definitive relation between Ai and ΔH° for (i) carbonaceous materials, metal organic frameworks (MOFs), carbon nanotubes, zeolites + hydrogen, and (ii) activated carbons + methane systems. The proposed theoretical framework of At and AH0 provides valuable guides for researchers in developing advanced porous adsorbents for methane and hydrogen uptake. © 2009 American Chemical Society.

New type of amidoxime-group-containing adsorbent for the recovery of uranium from seawater. III. Recycle use of adsorbent

International Nuclear Information System (INIS)

Omichi, H.; Katakai, A.; Sugo, T.; Okamoto, J.

1986-01-01

An amidoxime-group adsorbent for recovering uranium from seawater was made by radiation-induced graft polymerization of acrylonitrile onto polymeric fiber, followed by amidoximation. Uranium adsorption of the adsorbent contacted with seawater in a column increased with the increase in flow rate, then leveled off. The relationship between uranium adsorption in a batch process and the ratio of the amount of seawater to that of adsorbent was found to be effective in evaluating adsorbent contacted with any amount of seawater. The conditioning of the adsorbent with an alkaline solution at higher temperature (∼80 0 C) after the acid desorption recovered the adsorption ability to the original level. This made it possible to apply the adsorbent to recycle use. On the other hand, the adsorbent conditioned at room temperature or that without conditioning lost adsorption ability during recycle use. The increase in water uptake was observed as one of the physical changes produced during recycle use of the alkaline-conditioned adsorbent, while the decrease in water uptake was observed with the unconditioned adsorbent. The IR spectra of the adsorbent showed a probability of reactions of amidoxime groups with acid and alkaline solutions, which can explain the change in uranium adsorption during the adsorption-desorption cycle

Ultra-Thin Optically Transparent Carbon Electrodes Produced from Layers of Adsorbed Proteins

Science.gov (United States)

Alharthi, Sarah A.; Benavidez, Tomas E.; Garcia, Carlos D.

2013-01-01

This work describes a simple, versatile, and inexpensive procedure to prepare optically transparent carbon electrodes, using proteins as precursors. Upon adsorption, the protein-coated substrates were pyrolyzed under reductive conditions (5% H2) to form ultra-thin, conductive electrodes. Because proteins spontaneously adsorb to interfaces forming uniform layers, the proposed method does not require a precise control of the preparation conditions, specialized instrumentation, or expensive precursors. The resulting electrodes were characterized by a combination of electrochemical, optical, and spectroscopic means. As a proof-of-concept, the optically-transparent electrodes were also used as substrate for the development of an electrochemical glucose biosensor. The proposed films represent a convenient alternative to more sophisticated, and less available, carbon-based nanomaterials. Furthermore, these films could be formed on a variety of substrates, without classical limitations of size or shape. PMID:23421732

A study of structure and properties of molecularly thin methanol film using the modified surface forces apparatus.

Science.gov (United States)

Zhao, Gutian; Cai, Di; Wu, Gensheng; Tan, Qiyan; Xiang, Li; Zhang, Yin; Xiang, Nan

2014-11-01

A novel approach for studying the adsorption and evaporation processes of molecularly thin methanol film by the modified surface forces apparatus (M-SFA) is reported. This method can be used precisely to measure the thickness, morphology, and mechanical properties of the film confined between two mica surfaces in a real-time manner at gas atmosphere. By observing the adsorption and evaporation processes of the methanol molecule, it is found that the first adsorbed layer of the methanol film on the mica surface behaves as a solid-like structure. The thickness of this layer is measured to be about 3.2 Å, approximately equal to the diameter of a methanol molecule. Besides, this first adsorbed layer can carry normalized loads of more than 5.6 atm due to the carrying capacity conserved by the bond of mica-OH. The outer layers of the methanol film are further adsorbed with the increase of the exposure time, which are liquid-like and can be easily eliminated out from the substrate. The present study suggests that the interacting mode between hydroxy and mica is of great potential in material science and biomedical systems. © 2014 Wiley Periodicals, Inc.

Electronic spectral properties of surfaces and adsorbates and atom-adsorbate van der Waals interactions

International Nuclear Information System (INIS)

Lovric, D.; Gumhalter, B.

1988-01-01

The relevance of van der Waals interactions in the scattering of neutral atoms from adsorbates has been recently confirmed by highly sensitive molecular-beam techniques. The theoretical descriptions of the collision dynamics which followed the experimental studies have necessitated very careful qualitative and quantitative examinations and evaluations of the properties of atom-adsorbate van der Waals interactions for specific systems. In this work we present a microscopic calculation of the strengths and reference-plane positions for van der Waals potentials relevant for scattering of He atoms from CO adsorbed on various metallic substrates. In order to take into account the specificities of the polarization properties of real metals (noble and transition metals) and of chemisorbed CO, we first calculate the spectra of the electronic excitations characteristic of the respective electronic subsystems by using various data sources available and combine them with the existing theoretical models. The reliability of the calculated spectra is then verified in each particular case by universal sum rules which may be established for the electronic excitations of surfaces and adsorbates. The substrate and adsorbate polarization properties which derive from these calculations serve as input data for the evaluation of the strengths and reference-plane positions of van der Waals potentials whose computed values are tabulated for a number of real chemisorption systems. The implications of the obtained results are discussed in regard to the atom-adsorbate scattering cross sections pertinent to molecular-beam scattering experiments

Surface electrons of helium films

International Nuclear Information System (INIS)

Studart, N.; Hipolito, O.

1986-01-01

Theoretical calculations of some properties of two-dimensional electrons on a liquid helium film adsorbed on a solid substrate are reviewed. We describe the spectrum of electron bound states on bulk helium as well on helium films. The correlational properties, such as the structure factor and correlation energy, are determined as functions of the film thickness for different types of substrates in the framework of a Generalized Random-Phase Approximation. The collective excitations of this system are also described. The results for electrons on the surface of thin films and bulk helium are easily obtained. we examine the electron interaction with the excitations of the liquid helium surface resulting in a new polaron state, which was observed very recently. The ground state energy and the effective mass of this polaron are determined by using the path-integral formalism and unitary-transformation method. Recent speculations about the phase diagram of electrons on the helium film are also discussed. (Author) [pt

Krypton retention on solid adsorbents

International Nuclear Information System (INIS)

Monson, P.R. Jr.

1980-01-01

Radioactive krypton-85 is released to the atmosphere in the off-gas from nuclear reprocessing plants. Three main methods have been suggested for removal of krypton from off-gas streams: cryogenic distillation; fluorocarbon absorption; and adsorption on solid sorbents. Use of solid adsorbents is the least developed of these methods, but offers the potential advantages of enhanced safety and lower operating costs. An experimental laboratory program was developed that will be used to investigate systematically many solid adsorbents (such as zeolites, i.e., mordenites) for trapping krypton in air. The objective of this investigation is to find an adsorbent that is more economical than silver-exchanged mordenite. Various physical and chemical characteristics such as adsorption isotherms, decontamination factors, co-adsorption, regeneration, and the mechanism and kinetics of noble gas adsorption were used to characterize the adsorbents. In the experimental program, a gas chromatograph using a helium ionization detector was used to measure the krypton in air before and after the adsorbent bed. This method can determine directly decontamination factors greater than 100

Cell for studying electron-adsorbed gas interactions; Cellule d'etudes des interactions electron-gaz adsorbe

Energy Technology Data Exchange (ETDEWEB)

Golowacz, H; Degras, D A [Commissariat a l' Energie Atomique, 91 - Saclay (France). Centre d' Etudes Nucleaires, Deptartement de Physique des Plasmas et de la Fusion Controlee, Service de Physique Appliquee, Service de Physique des Interractions Electroniques, Section d' Etude des Interactions Gaz-Solides

1967-07-01

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) [French] Les caracteristiques geometriques et technologiques generales d'une cellule d'etude des interactions entre un faisceau d'electrons et un gaz adsorbe sont donnees. Un calcul simplifie permet de prevoir les frequences de resonance des ions de surface crees par l'impact des electrons sur le gaz adsorbe. Les donnees experimentales sur l'oxyde de carbone et le neon confirment les previsions du calcul. (auteurs)

Photochemical oxygen reduction by zinc phthalocyanine and silver/gold nanoparticle incorporated silica thin films

Energy Technology Data Exchange (ETDEWEB)

Pal, Manas; Ganesan, Vellaichamy, E-mail: velganesh@yahoo.com; Azad, Uday Pratap

2012-12-15

Silver or gold nanoparticles are synthesized using a borohydride reduction method and are anchored simultaneously into/onto the mercaptopropyl functionalized silica. Later, zinc phthalocyanine is adsorbed onto the above materials. Thin films of these materials are prepared by coating an aqueous colloidal suspension of the respective material onto glass plates. Visible light irradiation of these films in oxygen saturated, stirred aqueous solutions effectively reduces oxygen to hydrogen peroxide. The photocatalytic reduction of oxygen is explained on the basis of the semiconducting properties of the silica films. The back electron transfer reaction is largely prevented by means of a sacrificial electron donor, triethanolamine. - Highlights: Black-Right-Pointing-Pointer Zinc phthalocyanine adsorbed silica materials were prepared. Black-Right-Pointing-Pointer Thin films of these materials photocatalytically reduce oxygen. Black-Right-Pointing-Pointer The photocatalysis is explained based on semiconductor properties of the materials. Black-Right-Pointing-Pointer Metal nanoparticles increase the photocatalytic efficiency of the materials.

Electrochemical and spectroelectrochemical characterization of different mesoporous TiO2 film electrodes for the immobilization of Cytochrome c

Science.gov (United States)

Katsiaounis, Stavros; Tiflidis, Christina; Tsekoura, Christina; Topoglidis, Emmanuel

2018-03-01

In this work three different mesoporous TiO2 film electrodes were prepared and used for the immobilization of Cytochrome c (Cyt-c). Films prepared via a standard sol-gel route (SG-films) were compared with commercially available benchmark nanotitania materials, namely P25 Degussa (P25-films) and Dyesol nanopaste (Dyesol films). Their properties, film deposition characteristics and their abilities to adsorb protein molecules in a stable and functional way were examined. We investigated whether it is possible, rather than preparing TiO2 films using multistep, lengthy and not always reproducible sol-gel procedures, to use commercially available nanotitania materials and produce reproducible films faster that exhibit all the properties that make TiO2 films ideal for protein immobilization. Although these materials are formulated primarily for dye-sensitized solar cell applications, in this study we found out that protein immobilization is facile and remarkably stable on all of them. We also investigated their electrochemical properties by using cyclic voltammetry and spectroelectrochemistry and found out that not only direct reduction of Fe(III)-heme to Fe(II)-heme of immobilized Cyt-c was possible on all films but that the adsorbed protein remained electroactive.

Bioavailability of Carbon Nanomaterial-Adsorbed Polycyclic Aromatic Hydrocarbons to Pimphales promelas: Influence of Adsorbate Molecular Size and Configuration.

Science.gov (United States)

Linard, Erica N; Apul, Onur G; Karanfil, Tanju; van den Hurk, Peter; Klaine, Stephen J

2017-08-15

Despite carbon nanomaterials' (CNMs) potential to alter the bioavailability of adsorbed contaminants, information characterizing the relationship between adsorption behavior and bioavailability of CNM-adsorbed contaminants is still limited. To investigate the influence of CNM morphology and organic contaminant (OC) physicochemical properties on this relationship, adsorption isotherms were generated for a suite of polycyclic aromatic hydrocarbons (PAHs) on multiwalled carbon nanotubes (MWCNTs) and exfoliated graphene (GN) in conjunction with determining the bioavailability of the adsorbed PAHs to Pimphales promelas using bile analysis via fluorescence spectroscopy. Although it appeared that GN adsorbed PAHs indiscriminately compared to MWCNTs, the subsequent bioavailability of GN-adsorbed PAHs was more sensitive to PAH morphology than MWCNTs. GN was effective at reducing bioavailability of linear PAHs by ∼70%, but had little impact on angular PAHs. MWCNTs were sensitive to molecular size, where bioavailability of two-ringed naphthalene was reduced by ∼80%, while bioavailability of the larger PAHs was reduced by less than 50%. Furthermore, the reduction in bioavailability of CNM-adsorbed PAHs was negatively correlated with the amount of CNM surface area covered by the adsorbed-PAHs. This study shows that the variability in bioavailability of CNM-adsorbed PAHs is largely driven by PAH size, configuration and surface area coverage.

Organic adsorbates on metal surfaces. PTCDA and NTCDA on AG(110)

Energy Technology Data Exchange (ETDEWEB)

Abbasi, Afshin

2010-02-22

Polyaromatic molecules functionalized with carboxylic groups have served as model systems for the growth of organic semiconducting films on a large variety of substrates. Most non-reactive substrates allow for a growth mode compatible with the bulk phase of the molecular crystal with two molecules in the unit cell, but some more reactive substrates including Ag(111) and Ag(110) can induce substantial changes in the first monolayer (ML). In the specific case of Ag(110), the adsorbate unit cell of both NTCDA and PTCDA resembles a brickwall structure, with a single molecule in the unit cell. From this finding, it can be concluded that the adsorbate-substrate interaction is stronger than typical inter-molecular binding energies in the respective bulk phases. In the present work, the interactions between small Ag(110) clusters and a single NTCDA or PTCDA molecule are investigated with different ab initio techniques. Four major ingredients contribute to the binding between adsorbate and substrate: Directional bonds between Ag atoms in the topmost layer and the oxygen atoms of the molecule, Pauli repulsion between filled orbitals of molecule and substrate, an attractive van-der-Waals interaction, and a negative net charge on the molecule inducing positive image charges in the substrate, resulting therefore in an attractive Coulomb interaction between these opposite charges. As both Hartree-Fock theory and density functional theory with typical gradient-corrected density functional do not contain any long range correlation energy required for dispersion interactions, we compare these approaches with the fastest numerical technique where the leading term of the van-der-Waals interaction is included, i.e. second order Moeller-Plesset theory (MP2). Both Hartree-Fock and density functional theory result in bended optimized geometries where the adsorbate is interacting mainly via the oxygen atoms, with the core of the molecule repelled from the substrate. Only at the MP2 level

Bilirubin adsorption on nanocrystalline titania films

International Nuclear Information System (INIS)

Yang Zhengpeng; Si Shihui; Fung Yingsing

2007-01-01

Bilirubin produced from hemoglobin metabolism and normally conjugated with albumin is a kind of lipophilic endotoxin, and can cause various diseases when its concentration is high. Bilirubin adsorption on the nanocrystalline TiO 2 films was investigated using quartz crystal microbalance, UV-vis and IR techniques, and factors affecting its adsorption such as pH, bilirubin concentration, solution ionic strength, temperature and thickness of TiO 2 films were discussed. The amount of adsorption and parameters for the adsorption kinetics were estimated from the frequency measurements of quartz crystal microbalance. A fresh surface of the nanocrystalline TiO 2 films could be photochemically regenerated because holes and hydroxyl radicals were generated by irradiating the nanocrystalline TiO 2 films with UV light, which could oxidize and decompose organic materials, and the nanocrystalline TiO 2 films can be easily regenerated when it is used as adsorbent for the removal of bilirubin

Organic and Inorganic Dyes in Polyelectrolyte Multilayer Films

Science.gov (United States)

Ball, Vincent

2012-01-01

Polyelectrolyte multilayer films are a versatile functionalization method of surfaces and rely on the alternated adsorption of oppositely charged species. Among such species, charged dyes can also be alternated with oppositely charged polymers, which is challenging from a fundamental point of view, because polyelectrolytes require a minimal number of charges, whereas even monovalent dyes can be incorporated during the alternated adsorption process. We will not only focus on organic dyes but also on their inorganic counterparts and on metal complexes. Such films offer plenty of possible applications in dye sensitized solar cells. In addition, dyes are massively used in the textile industry and in histology to stain textile fibers or tissues. However, the excess of non bound dyes poses serious environmental problems. It is hence of the highest interest to design materials able to adsorb such dyes in an almost irreversible manner. Polyelectrolyte multilayer films, owing to their ion exchange behavior can be useful for such a task allowing for impressive overconcentration of dyes with respect to the dye in solution. The actual state of knowledge of the interactions between charged dyes and adsorbed polyelectrolytes is the focus of this review article.

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

International Nuclear Information System (INIS)

Koske, P.H.; Ohlrogge, K.

1984-01-01

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.) [de

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

International Nuclear Information System (INIS)

Motojima, K.; Kawamura, F.

1984-01-01

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

Adsorbent Alkali Conditioning for Uranium Adsorption from Seawater. Adsorbent Performance and Technology Cost Evaluation

International Nuclear Information System (INIS)

Tsouris, Costas; Mayes, Richard T.; Janke, Christopher James; Dai, Sheng; Das, S.; Liao, W.P.; Kuo, Li-Jung; Wood, Jordana; Gill, Gary; Byers, Maggie Flicker; Schneider, Eric

2015-01-01

The Fuel Resources program of the Fuel Cycle Research and Development program of the Office of Nuclear Energy (NE) is focused on identifying and implementing actions to assure that nuclear fuel resources are available in the United States. An immense source of uranium is seawater, which contains an estimated amount of 4.5 billion tonnes of dissolved uranium. This unconventional resource can provide a price cap and ensure centuries of uranium supply for future nuclear energy production. NE initiated a multidisciplinary program with participants from national laboratories, universities, and research institutes to enable technical breakthroughs related to uranium recovery from seawater. The goal is to develop advanced adsorbents to reduce the seawater uranium recovery technology cost and uncertainties. Under this program, Oak Ridge National Laboratory (ORNL) has developed a new amidoxime-based adsorbent of high surface area, which tripled the uranium capacity of leading Japanese adsorbents. Parallel efforts have been focused on the optimization of the physicochemical and operating parameters used during the preparation of the adsorbent for deployment. A set of parameters that need to be optimized are related to the conditioning of the adsorbent with alkali solution, which is necessary prior to adsorbent deployment. Previous work indicated that alkali-conditioning parameters significantly affect the adsorbent performance. Initiated in 2014, this study had as a goal to determine optimal parameters such as base type and concentration, temperature, and duration of conditioning that maximize the uranium adsorption performance of amidoxime functionalized adsorbent, while keeping the cost of uranium production low. After base-treatment at various conditions, samples of adsorbent developed at ORNL were tested in this study with batch simulated seawater solution of 8-ppm uranium concentration, batch seawater spiked with uranium nitrate at 75-100 ppb uranium, and continuous

Adsorbent Alkali Conditioning for Uranium Adsorption from Seawater. Adsorbent Performance and Technology Cost Evaluation

Energy Technology Data Exchange (ETDEWEB)

Tsouris, Costas [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Mayes, Richard T. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Janke, Christopher James [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Dai, Sheng [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Das, S. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Liao, W. -P. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Kuo, Li-Jung [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Wood, Jordana [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Gill, Gary [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Byers, Maggie Flicker [Univ. of Texas, Austin, TX (United States); Schneider, Eric [Univ. of Texas, Austin, TX (United States)

2015-09-30

The Fuel Resources program of the Fuel Cycle Research and Development program of the Office of Nuclear Energy (NE) is focused on identifying and implementing actions to assure that nuclear fuel resources are available in the United States. An immense source of uranium is seawater, which contains an estimated amount of 4.5 billion tonnes of dissolved uranium. This unconventional resource can provide a price cap and ensure centuries of uranium supply for future nuclear energy production. NE initiated a multidisciplinary program with participants from national laboratories, universities, and research institutes to enable technical breakthroughs related to uranium recovery from seawater. The goal is to develop advanced adsorbents to reduce the seawater uranium recovery technology cost and uncertainties. Under this program, Oak Ridge National Laboratory (ORNL) has developed a new amidoxime-based adsorbent of high surface area, which tripled the uranium capacity of leading Japanese adsorbents. Parallel efforts have been focused on the optimization of the physicochemical and operating parameters used during the preparation of the adsorbent for deployment. A set of parameters that need to be optimized are related to the conditioning of the adsorbent with alkali solution, which is necessary prior to adsorbent deployment. Previous work indicated that alkali-conditioning parameters significantly affect the adsorbent performance. Initiated in 2014, this study had as a goal to determine optimal parameters such as base type and concentration, temperature, and duration of conditioning that maximize the uranium adsorption performance of amidoxime functionalized adsorbent, while keeping the cost of uranium production low. After base-treatment at various conditions, samples of adsorbent developed at ORNL were tested in this study with batch simulated seawater solution of 8-ppm uranium concentration, batch seawater spiked with uranium nitrate at 75-100 ppb uranium, and continuous

Growth Process of Passive Films Formed on Austenitic Stainless Steels under Atmospheric Environments

Energy Technology Data Exchange (ETDEWEB)

Jung, Rock-Hoon [Samsung Heavy Industries Co.,Ltd, Seoul (Korea, Republic of); Fujimoto, Shinji [Osaka University, Osaka (Japan)

2014-06-15

The excellent protection ability of stainless steel derives from the highly Cr enriched passive film which is formed as a result of selective dissolution of Fe into the bulk solution. On the other hand, the passive films formed under atmospheric conditions do not necessarily exhibit Cr enrichment, because the amount of the solution on a stainless steel as an adsorbed thin water layer is not sufficient for selective dissolution of Fe. Therefore, the modification of passive films may occur as tiny mass transfer between hydroxide layer and oxide layer of the passive films, and/or occasional replace of the adsorbed thin water layer. In the present work, in order to discuss atmospheric corrosion, passive films on stainless steels formed under humid atmospheric environments were characterized using X-ray photoelectron spectroscopy. Optimal conditions for the pulse anodizing were a duty ratio of 91%, a frequency of 0.09 Hz, and an anodizing time of 600 s. Pulse anodizing caused a remarkable decrease in the surface porosity (11-fold) and an increase in the film thickness (1.6-fold) from those obtained under a constant potential of 10 V{sub Ag/AgCl}. Furthermore, an Al-enriched oxide layer was formed on the outer surface of MgO.

Mercury adsorption to gold nanoparticle and thin film surfaces

Science.gov (United States)

Morris, Todd Ashley

Mercury adsorption to gold nanoparticle and thin film surfaces was monitored by spectroscopic techniques. Adsorption of elemental mercury to colloidal gold nanoparticles causes a color change from wine-red to orange that was quantified by UV-Vis absorption spectroscopy. The wavelength of the surface plasmon mode of 5, 12, and 31 nm gold particles blue-shifts 17, 14, and 7.5 nm, respectively, after a saturation exposure of mercury vapor. Colorimetric detection of inorganic mercury was demonstrated by employing 2.5 nm gold nanoparticles. The addition of low microgram quantities of Hg 2+ to these nanoparticles induces a color change from yellow to peach or blue. It is postulated that Hg2+ is reduced to elemental mercury by SCN- before and/or during adsorption to the nanoparticle surface. It has been demonstrated that surface plasmon resonance spectroscopy (SPRS) is sensitive to mercury adsorption to gold and silver surfaces. By monitoring the maximum change in reflectivity as a function of amount of mercury adsorbed to the surface, 50 nm Ag films were shown to be 2--3 times more sensitive than 50 nm Au films and bimetallic 15 nm Au/35 nm Ag films. In addition, a surface coverage of ˜40 ng Hg/cm2 on the gold surface results in a 0.03° decrease in the SPR angle of minimum reflectivity. SPRS was employed to follow Hg exposure to self-assembled monolayers (SAMs) on Au. The data indicate that the hydrophilic or hydrophobic character of the SAM has a significant effect on the efficiency of Hg penetration. Water adsorbed to carboxylic acid end group of the hydrophilic SAMs is believed to slow the penetration of Hg compared to methyl terminated SAMs. Finally, two protocols were followed to remove mercury from gold films: immersion in concentrated nitric acid and thermal annealing up to 200°C. The latter protocol is preferred because it removes all of the adsorbed mercury from the gold surface and does not affect the morphology of the gold surface.

Characterization of casein and poly-l-arginine multilayer films

Science.gov (United States)

Szyk-Warszyńska, Lilianna; Kilan, Katarzyna; Socha, Robert P.

2014-06-01

Thin films containing casein appear to be a promising material for coatings used in the medical area to promote biomineralization. alfa- and beta-casein and poly-L-arginine multilayer films were formed by the layer-by layer technique and their thickness and mass were analyzed by ellipsometry and quartz crystal microbalance with dissipation monitoring (QCM-D). We investigated the effect of the type of casein used for the film formation and of the polyethyleneimine anchoring layer on the thickness and mass of adsorbed films. The analysis of the mass of films during their post-treatment with the solutions of various ionic strength and pH provided the information concerning films stability, while the XPS elemental analysis confirmed binding of calcium ions by the casein embedded in the multilayers.

Measurement of benzenethiol adsorption to nanostructured Pt, Pd, and PtPd films using Raman spectroelectrochemistry.

Science.gov (United States)

Pomfret, Michael B; Pietron, Jeremy J; Owrutsky, Jeffrey C

2010-05-04

Raman spectroscopy and electrochemical methods were used to study the behavior of the model adsorbate benzenethiol (BT) on nanostructured Pt, Pd, and PtPd electrodes as a function of applied potential. Benzenethiol adsorbs out of ethanolic solutions as the corresponding thiolate, and voltammetric stripping data reveal that BT is oxidatively removed from all of the nanostructured metals upon repeated oxidative and reductive cycling. Oxidative stripping potentials for BT increase in the order Pt oxidizing potentials via cleavage of the Pt-S bond. In contrast, on nanoscale Pd and PtPd, BT is irreversibly lost due to cleavage of BT C-S bonds at oxidizing potentials, which leaves adsorbed sulfur oxides on Pd and PtPd films and effects the desulfurization of BT. While Pd and PtPd films are less sulfur-resistant than Pt films, palladium oxides, which form at higher potentials than Pt oxides, oxidatively desulfurize BT. In situ spectroelectrochemical Raman spectroscopy provides real-time, chemically specific information that complements the cyclic voltammetric data. The combination of these techniques affords a powerful and convenient method for guiding the development of sulfur-tolerant PEMFC catalysts.

Volatile organic compounds adsorption using different types of adsorbent

Directory of Open Access Journals (Sweden)

Pimanmes Chanayotha

2014-09-01

Full Text Available Adsorbents were synthesized from coconut shell, coal and coke by pyrolysis followed by chemical activation process. These synthesized materials were used as adsorbents in adsorption test to determine the amount of volatile organic compounds (VOCs namely, 2-Hydroxyethyl methacrylate (HEMA, Octamethylcyclotetrasiloxane and Alkanes standard solution (C8-C20. The adsorption capacities of both synthesized adsorbents and commercial grade adsorbents (Carbotrap™ B and Carbotrap™ C were also compared. It was found that adsorbent A402, which was produced from coconut shell, activated with 40% (wt. potassium hydroxide and at activating temperature of 800°C for 1 hr, could adsorb higher amount of both HEMA and Octamethylcyclotetrasiloxane than other synthesized adsorbents. The maximum adsorption capacity of adsorbent A402 in adsorbing HEMA and Octamethylcyclotetrasiloxane were 77.87% and 50.82% respectively. These adsorption capabilities were 79.73% and 70.07% of the adsorption capacity of the commercial adsorbent Carbotrap™ B respectively. All three types of the synthesized adsorbent (A402, C302, C402 showed the capability to adsorb alkanes standard solution through the range of C8-C20 . However, their adsorption capacities were high in a specific range of C10-C11. The result from the isotherm plot was indicated that surface adsorption of synthesized adsorbent was isotherm type I while the surface adsorption of commercial adsorbent was isotherm type III.

Theoretical Insight of Physical Adsorption for a Single-Component Adsorbent + Adsorbate System: I. Thermodynamic Property Surfaces

KAUST Repository

Chakraborty, Anutosh; Saha, Bidyut Baran; Ng, Kim Choon; Koyama, Shigeru; Srinivasan, Kandadai

2009-01-01

Thermodynamic property surfaces for a single-component adsorbent + adsorbate system are derived and developed from the viewpoint of classical thermodynamics, thermodynamic requirements of chemical equilibrium, Gibbs law, and Maxwell relations

Understanding Trends in Catalytic Activity: The Effect of Adsorbate-Adsorbate Interactions for CO Oxidation Over Transition Metals

DEFF Research Database (Denmark)

Grabow, Lars; Larsen, Britt Hvolbæk; Nørskov, Jens Kehlet

2010-01-01

Using high temperature CO oxidation as the example, trends in the reactivity of transition metals are discussed on the basis of density functional theory (DFT) calculations. Volcano type relations between the catalytic rate and adsorption energies of important intermediates are introduced...... and the effect of adsorbate-adsorbate interaction on the trends is discussed. We find that adsorbate-adsorbate interactions significantly increase the activity of strong binding metals (left side of the volcano) but the interactions do not change the relative activity of different metals and have a very small...... influence on the position of the top of the volcano, that is, on which metal is the best catalyst....

A new radiochromic film for radiation processing

International Nuclear Information System (INIS)

Sidney, L.N.; Lynch, D.C.; Willett, P.S.; Englund, W.J.

1990-01-01

Acid-sensitive leuco dyes in combination with a chlorine-containing polymer have been used to make a new kind of radiochromic film for radiation processing. When exposed to gamma, electron beam, or high intensity ultraviolet radiation, these films undergo a color change from colorless to royal blue, fuschia, or black, depending on the dye. The dose response for gamma and electron beam radiation has been characterized using reflection and transmission spectrophotometry over an adsorbed dose range of 1 to 100 kGy. The primary features of the films include improved color stability before and after irradiation and improved moisture resistance. The response and stability of the films make them useful for indicator (qualitative) or dosimeter (quantitative) films or labels for sterilization of medical products, food (especially meat, poultry, and spices), pharmaceuticals, and cosmetics, and the crosslinking of plastics, and the curing of polymer coatings. Large pieces of the film could be used in dose mapping when setting up and validating radiation processes and medical treatments

Adsorbate-induced one-dimensional long-range modulation of an epitaxial insulator film

International Nuclear Information System (INIS)

Ernst, W.; Eichmann, M.; Pfnuer, H.; Jonas, K.-L.; Oeynhausen, V. von; Meiwes-Broer, K.H.

2002-01-01

Using low-energy electron diffraction and scanning tunneling microscopy, we found that epitaxial NaCl films grown on Ge(100) with thicknesses up to (at least) 15 monolayers can be modulated with a period of six lattice constants and an amplitude directed mainly normal to their surface. The (6x1) periodicity on the NaCl films is induced by a preadsorbed Na layer at very low coverages (Θ≅0.06), that form chain structures with a sixfold periodicity in one dimension. At 10 monolayers thickness of NaCl a modulation amplitude of 0.28 Aa was obtained

Growth of n-alkane films on a single-crystal substrate

DEFF Research Database (Denmark)

Wu, Z. U.; Ehrlich, S. N.; Matthies, B.

2001-01-01

The structure and growth mode of alkane films (n-C/sub n/H/sub 2n+2/; n=4, 6, 7) adsorbed on a Ag(111) surface have been investigated by synchrotron X-ray scattering. New models are proposed for the butane (n=4) and hexane (n=6) monolayer and butane bilayer structures. Specular reflectivity scans...... reveal that growth of all films is preempted between two and three layers by nucleation of bulk particles oriented with a single bulk crystal plane parallel to the film. In the case of butane, the bulk particles also have a fixed azimuthal relationship with the film resulting in complete epitaxy....

Kinetic analysis on photocatalytic degradation of gaseous acetaldehyde, ammonia and hydrogen sulfide on nanosized porous TiO2 films

Directory of Open Access Journals (Sweden)

Iis Sopyan

2007-01-01

Full Text Available The characteristics of the UV illumination-assisted degradation of gaseous acetaldehyde, hydrogen sulfide, and ammonia on highly active nanostructured-anatase and rutile films were investigated. It was found that the anatase film showed a higher photocatalytic activity than the counterpart did, however, the magnitude of difference in the photocatalytic activity of both films decreased in the order ammonia>acetaldehyde>hydrogen sulfide. To elucidate the reasons for the observation, the adsorption characteristics and the kinetics of photocatalytic degradation of the three reactants on both films were analyzed. The adsorption analysis examined using a simple Langmuir isotherm, showed that adsorbability on both films decreased in the order ammonia>acetaldehyde>hydrogen sulfide, which can be explained in terms of the decreasing electron-donor capacity. Acetaldehyde and ammonia adsorbed more strongly and with higher coverage on anatase film (1.2 and 5.6 molecules/nm2, respectively than on rutile (0.6 and 4.7 molecules/nm2, respectively. Conversely, hydrogen sulfide molecules adsorbed more strongly on rutile film (0.7 molecules/nm2 than on anatase (0.4 molecules/nm2. Exposure to UV light illumination brought about the photocatalytic oxidation of the three gases in contact with both TiO2 films, and the decrease in concentration were measured, and their kinetics are analyzed in terms of the Langmuir–Hinshelwood kinetic model. From the kinetic analysis, it was found that the anatase film showed the photocatalytic activities that were factors of ~8 and ~5 higher than the rutile film for the degradation of gaseous ammonia and acetaldehyde, respectively. However, the activity was only a factor of ~1.5 higher for the photodegradation of hydrogen sulfide. These observations are systematically explained by the charge separation efficiency and the adsorption characteristics of each catalyst as well as by the physical and electrochemical properties of each

Mercury adsorption properties of sulfur-impregnated adsorbents

Science.gov (United States)

Hsi, N.-C.; Rood, M.J.; Rostam-Abadi, M.; Chen, S.; Chang, R.

2002-01-01

Carbonaceous and noncarbonaceous adsorbents were impregnated with elemental sulfur to evaluate the chemical and physical properties of the adsorbents and their equilibrium mercury adsorption capacities. Simulated coal combustion flue gas conditions were used to determine the equilibrium adsorption capacities for Hg0 and HgCl2 gases to better understand how to remove mercury from gas streams generated by coal-fired utility power plants. Sulfur was deposited onto the adsorbents by monolayer surface deposition or volume pore filling. Sulfur impregnation increased the total sulfur content and decreased the total and micropore surface areas and pore volumes for all of the adsorbents tested. Adsorbents with sufficient amounts of active adsorption sites and sufficient microporous structure had mercury adsorption capacities up to 4,509 ??g Hg/g adsorbent. Elemental sulfur, organic sulfur, and sulfate were formed on the adsorbents during sulfur impregnation. Correlations were established with R2>0.92 between the equilibrium Hg0/HgCl2 adsorption capacities and the mass concentrations of elemental and organic sulfur. This result indicates that elemental and organic sulfur are important active adsorption sites for Hg0 and HgCl2.

Adsorption of human tear lipocalin to human meibomian lipid films.

Science.gov (United States)

Millar, Thomas J; Mudgil, Poonam; Butovich, Igor A; Palaniappan, Chendur K

2009-01-01

Tear lipocalin (Tlc) is a major lipid binding protein in tears and is thought to have an important role in stabilizing the Meibomian lipid layer by transferring lipids to it from the aqueous layer or ocular surface, or by adsorbing to it directly. These possible roles have been investigated in vitro using human Tlc. Tlc was purified from human tears by size exclusion chromatography followed by ion exchange chromatography. Three additional samples of the Tlc were prepared by lipidation, delipidation, and relipidation. The lipids extracted from the purified Tlc were analyzed by HPLC-MS followed by fragmentation. Adsorption of these different forms of Tlc to a human Meibomian lipid film spread on the surface of an artificial tear buffer in a Langmuir trough were observed by recording changes in the pressure with time (Pi-T profile) and monitoring the appearance of the film microscopically. These results were compared with similar experiments using a bovine Meibomian lipid film. The results indicated that Tlc binds slowly to a human Meibomian lipid film compared with lysozyme or lactoferrin, even at 37 degrees C. The adsorption of Tlc to a human Meibomian lipid film was very different from its adsorption to a bovine Meibomian lipid film, indicating the nature of the lipids in the film is critical to the adsorption process. Similarly, the different forms of Tlc had quite distinct adsorption patterns, as indicated both by changes in Pi-T profiles and the microscopic appearance of the films. It was concluded that human Tlc was capable of adsorbing to and penetrating into a Meibomian lipid layer, but this process is very complex and depends on both the types of lipids bound to Tlc and the lipid complement comprising the Meibomian lipid film.

Adsorption of Human Tear Lipocalin to Human Meibomian Lipid Films

Science.gov (United States)

Millar, Thomas J.; Mudgil, Poonam; Butovich, Igor A.; Palaniappan, Chendur K.

2009-01-01

Purpose Tear lipocalin (Tlc) is a major lipid binding protein in tears and is thought to have an important role in stabilizing the Meibomian lipid layer by transferring lipids to it from the aqueous layer or ocular surface, or by adsorbing to it directly. These possible roles have been investigated in vitro using human Tlc. Methods Tlc was purified from human tears by size exclusion chromatography followed by ion exchange chromatography. Three additional samples of the Tlc were prepared by lipidation, delipidation, and relipidation. The lipids extracted from the purified Tlc were analyzed by HPLC-MS followed by fragmentation. Adsorption of these different forms of Tlc to a human Meibomian lipid film spread on the surface of an artificial tear buffer in a Langmuir trough were observed by recording changes in the pressure with time (∏-T profile) and monitoring the appearance of the film microscopically. These results were compared with similar experiments using a bovine Meibomian lipid film. Results The results indicated that Tlc binds slowly to a human Meibomian lipid film compared with lysozyme or lactoferrin, even at 37°C. The adsorption of Tlc to a human Meibomian lipid film was very different from its adsorption to a bovine Meibomian lipid film, indicating the nature of the lipids in the film is critical to the adsorption process. Similarly, the different forms of Tlc had quite distinct adsorption patterns, as indicated both by changes in ∏-T profiles and the microscopic appearance of the films. Conclusions It was concluded that human Tlc was capable of adsorbing to and penetrating into a Meibomian lipid layer, but this process is very complex and depends on both the types of lipids bound to Tlc and the lipid complement comprising the Meibomian lipid film. PMID:18757516

Diffusion of radioactively tagged penetrants through rubbery polymers. II. Dependence on molecular length of penetrant

International Nuclear Information System (INIS)

Rhee, C.K.; Ferry, J.D.; Fetters, L.J.

1977-01-01

The diffusion of radioactively tagged n-hexadecane, n-dotriacontane, and a polybutadiene oligomer with molecular weight 1600 has been studied in 12 rubbery polymers. Diffusion coefficients were obtained from the theory for the thin smear method: for n-hexadecane and for n-dotriacontane (with one exception), in the form appropriate for a completely miscible polymer-penetrant pair, and for the oligomer in the form appropriate for slow entry of the pentrant across the penetrant-polymer interface. For the four flexible linear penetrants, n-dodecane, n-hexadecane, n-dotriacontane, and oligomer, the ratios of diffusion coefficients (or translational friction coefficients) are nearly the same in every polymer. It is concluded that these penetrants travel with similar segmentwise motions, although that is not the case with bulkier, more rigid penetrants. For the three normal paraffins, the friction coefficient is approximately proportional to molecular weight, but that for the oligomer is smaller than would be predicted on this basis

Influence of fluoride-detergent combinations on the visco-elasticity of adsorbed salivary protein films

NARCIS (Netherlands)

Veeregowda, Deepak H.; van der Mei, Henny C.; Busscher, Henk J.; Sharma, Prashant K.

The visco-elasticity of salivary-protein films is related to mouthfeel, lubrication, biofilm formation, and protection against erosion and is influenced by the adsorption of toothpaste components. The thickness and the visco-elasticity of hydrated films (determined using a quartz crystal

SFG investigation of adsorbed CO and NO on NiO(111) surface

Energy Technology Data Exchange (ETDEWEB)

Bandara, Athula; Dobashi, Shinsaku; Kubota, Jun; Onda, Ken; Wada, Akihide; Domen, Kazunari; Hirose, Chiaki [Tokyo Inst. of Tech., Yokohama (Japan). Research Lab. of Resources Utilization; Kano, S.S.

1997-07-01

Adsorption structures of CO and NO on the NiO(111) film grown on Ni(111) crystal have been investigated by sum frequency generation (SFG) spectroscopy and infrared reflection absorption spectroscopy (IRAS). The CO stretching band of adsorbed CO on NiO(111) was observed at 2144 cm{sup -1} on the SFG spectra for both p- and s-polarized visible light. However, adsorbed NO on NiO(111) was observed at 1805 cm{sup -1} on the SFG spectra only for the p-polarized visible light. The results suggest that the adsorbed CO molecule was tilted from the surface normal but the NO molecule was perpendicular to the surface. These orientations of CO and NO reflect the surface structure of NiO(111) which has (2 x 2)-reconstructed microfacets. Adsorption of CO on Ni(111) instead of NiO(111) was also examined by SFG and IRAS. Absorption bands due to linear and bridged CO were observed at 2076 and 1918 cm{sup -1}, respectively, by IRAS. On the other hand, the linear CO molecules on Ni(111) gave an SFG peak at 2076 cm{sup -1} only for the p-polarized visible light indicating the CO molecules are perpendicular to the surface, and bridged CO molecules did not give any SFG signal. The absence of the bridged CO signal is believed to be due to the smaller Raman tensor of bridged CO. (author)

SFG investigation of adsorbed CO and NO on NiO(111) surface

International Nuclear Information System (INIS)

Bandara, Athula; Dobashi, Shinsaku; Kubota, Jun; Onda, Ken; Wada, Akihide; Domen, Kazunari; Hirose, Chiaki; Kano, S.S.

1997-01-01

Adsorption structures of CO and NO on the NiO(111) film grown on Ni(111) crystal have been investigated by sum frequency generation (SFG) spectroscopy and infrared reflection absorption spectroscopy (IRAS). The CO stretching band of adsorbed CO on NiO(111) was observed at 2144 cm -1 on the SFG spectra for both p- and s-polarized visible light. However, adsorbed NO on NiO(111) was observed at 1805 cm -1 on the SFG spectra only for the p-polarized visible light. The results suggest that the adsorbed CO molecule was tilted from the surface normal but the NO molecule was perpendicular to the surface. These orientations of CO and NO reflect the surface structure of NiO(111) which has (2 x 2)-reconstructed microfacets. Adsorption of CO on Ni(111) instead of NiO(111) was also examined by SFG and IRAS. Absorption bands due to linear and bridged CO were observed at 2076 and 1918 cm -1 , respectively, by IRAS. On the other hand, the linear CO molecules on Ni(111) gave an SFG peak at 2076 cm -1 only for the p-polarized visible light indicating the CO molecules are perpendicular to the surface, and bridged CO molecules did not give any SFG signal. The absence of the bridged CO signal is believed to be due to the smaller Raman tensor of bridged CO. (author)

Method for modifying trigger level for adsorber regeneration

Science.gov (United States)

Ruth, Michael J.; Cunningham, Michael J.

2010-05-25

A method for modifying a NO.sub.x adsorber regeneration triggering variable. Engine operating conditions are monitored until the regeneration triggering variable is met. The adsorber is regenerated and the adsorbtion efficiency of the adsorber is subsequently determined. The regeneration triggering variable is modified to correspond with the decline in adsorber efficiency. The adsorber efficiency may be determined using an empirically predetermined set of values or by using a pair of oxygen sensors to determine the oxygen response delay across the sensors.

A novel fiber-based adsorbent technology

Energy Technology Data Exchange (ETDEWEB)

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

1997-10-01

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.

Novel Fiber-Based Adsorbent Technology; FINAL

International Nuclear Information System (INIS)

Nixon, P.G.; Tsukamoto, T.; Brose, D.J.

2001-01-01

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

Thermodynamic and structural study of two-dimensional phase transitions and orientational order in films of linear molecules with a large quadrupole moment, physi-sorbed on lamellar substrates

International Nuclear Information System (INIS)

Terlain, Anne

1984-01-01

The 2D (two-dimensional) phase transitions and orientational order in N 2 O, CO 2 , C 2 N 2 and C 2 D 2 films physi-sorbed on the (0001) face of graphite or lamellar halides, were studied experimentally by adsorption isotherm measurements and neutron diffraction. The thermodynamic functions derived from sets of isotherms suggest that crystal monolayers of N 2 O, CO 2 , and C 2 N 2 adsorbed on graphite are orientationally ordered and that the quadrupolar interaction stabilizes the 2D crystal with respect to the 2D liquid. This stabilization leads to an increase in the 2D triple point temperature, T 2t as compared with the 2D critical temperature T 2c . For C 2 N 2 this stabilization is so pronounced that T 2t becomes virtually higher than T 2c , and the phase diagram qualitatively different, having no gas-liquid coexistence domain. From a neutron diffraction experiment we have determined the crystal structure of the C 2 N 2 monolayer. It supports our interpretation of the monolayer phase diagram. In N 2 O, CO 2 , C 2 N 2 films adsorbed on graphite the molecules lie flat on the surface and their orientational order hence differs from that in the bulk crystals resulting in a loss of adsorbate-adsorbate interaction energy. Beyond a given film thickness this loss will not be compensated by the adsorbate-substrate interaction and the film will stop growing. For most of the films studied a partial wetting transition is observed at which the film thickness increases discontinuously with temperature. Although C 2 N 2 and C 2 D 2 monolayers on graphite have comparable adsorption energies, only C 2 D 2 is adsorbed on lamellar halides. This adsorption is possible only because the monolayer has a large entropy due to orientational disorder. For C 2 N 2 , which has a higher moment of inertia, such an orientational disorder cannot exist. (author) [fr

Optical and electrical characterizations of nanocomposite film of titania adsorbed onto oxidized multiwalled carbon nanotubes

International Nuclear Information System (INIS)

Feng Wei; Feng Yiyu; Wu Zigang; Fujii, Akihiko; Ozaki, Masanori; Yoshino, Katsumi

2005-01-01

Composite film containing titania electrostatically linked to oxidized multiwalled carbon nanotubes (TiO 2 -s-MWNTs) was prepared from a suspension of TiO 2 nanoparticles in soluble carbon nanotubes. The structure of the film was analysed principally by Fourier transform infrared spectroscopy, scanning electron micrography and x-ray diffraction. The optical and electrical characterizations of the film were investigated by UV-vis spectrum, photoluminescence and photoconductivity. The enhancement of photocurrent in the TiO 2 -s-MWNT film is discussed by taking the photoinduced charge transfer between the MWNT and TiO 2 into consideration

Correlation between mechanical behavior of protein films at the air/water interface and intrinsic stability of protein molecules

NARCIS (Netherlands)

Martin, A.H.; Cohen Stuart, M.A.; Bos, M.A.; Vliet, T. van

2005-01-01

The relation between mechanical film properties of various adsorbed protein layers at the air/water interface and intrinsic stability of the corresponding proteins is discussed. Mechanical film properties were determined by surface deformation in shear and dilation. In shear, fracture stress, σf,

WGS-Adsorbent Reaction Studies at Laboratory Scale

International Nuclear Information System (INIS)

Marano, M.; Torreiro, Y.

2014-01-01

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)

Zeta-potential of fouled thin film composite membrane

Energy Technology Data Exchange (ETDEWEB)

Ikeda, K.; Hachisuka, H.; Nakamura, T. [Nitto denko Corp., Ibaraki, (Japan); Kimura, S. [Kogakuin University, Tokyo (Japan). Dept. of Environ. Chemical Engineering; Ueyama, K. [Osaka University, Osaka (Japan). Dept. of Chemical Engineering

1999-10-01

The surface zeta-potential of a cross-linked polyamide thin film composite reverse osmosis membrane was measured using an electrophoresis method. It was confirmed that this method could be effectively applied to analyze the fouling of such membranes. It is known that the water flux of membranes drastically decreases as a result of fouling by surfactants. Although the surfactants adsorbed on reverse osmosis membranes could not be detected by conventional methods such as SEM, EDX and FT-IR, their presence could be clarified by the profile measurements of the surface zeta-potential. The profiles of the membrane surface zeta-potentials changed to more positive values in the measured pH range as a result of fouling by cationic or amphoteric surfactants. This measuring method of surface zeta-potentials allowed us to analyze a very small amount of fouling of a thin film composite reverse osmosis membrane. This method could be used to analyze the fouled surface of the thin film composite reverse osmosis membrane which is used for production of ultrapure water and shows a remarkable decrease in flux. It also became clear that this method is easy and effective for the reverse osmosis membrane surface analysis of adsorbed materials such as surfactants. (author)

Dissolved Air Flotation of arsenic adsorbent particles

Directory of Open Access Journals (Sweden)

Mario Enrique Santander Muñoz

2015-01-01

Full Text Available The removal of arsenic from synthetic effluent was studied using the adsorbent particle flotation technique (APF and dissolved air flotation (DAF. A sample of an iron mineral was used as adsorbent particles of arsenic, ferric chloride as coagulant, cationic poly-acrylamide (NALCO 9808 as flocculants, and sodium oleate as collector. Adsorption studies to determine the pH influence, contact time, and adsorbent particles concentration on the adsorption of arsenic were carried out along with flotation studies to determine the removal efficiency of adsorbents particles. The results achieved indicate that the adsorption kinetic of arsenic is very rapid and that in range of pH’s from 2 to 7 the adsorption percentages remain constant. The equilibrium conditions were achieved in 60 minutes and about 95% of arsenic was adsorbed when used an adsorbent concentration of 2 g/L and pH 6.3. The maximum adsorption capacity of adsorbent particles was 4.96 mg/g. The mean free energy of adsorption (E was found to be 2.63 kJ/mol, which suggests physisorption. The results of the flotation studies demonstrated that when synthetic effluents with 8.9 mg/L of arsenic were treated under the following experimental conditions; 2 g/L of adsorbent particles, 120 mg/L of Fe(III, 2 mg/L of Nalco 9808, 20 mg/L of sodium oleate, and 40% of recycle ratio in the DAF, it was possible to reach 98% of arsenic removal and 6.3 NTU of residual turbidity in clarified synthetic effluent.

Krypton retention on solid adsorbents

International Nuclear Information System (INIS)

Monson, P.R. Jr.

1982-01-01

An experimental laboratory program was conducted to develop economical solid adsorbents for the retention of krypton from a dissolver off-gas stream. The study indicates that a solid adsorbent system is feasible and competitive with other developing systems which utilize fluorocarbon absorption nd cryogenic distillation. This technology may have potential applications not only in nuclear fuel reprocessing plants, but also in nuclear reactors and in environmental monitoring. Of the 13 prospective adsorbents evaluated with respect to adsorption capacity and cost, the commercially available hydrogen mordenite was the most cost-effective material at subambient temperatures (-40 0 to -80 0 C). Silver mordenite has a higher capacity for krypton retention, but is 50 times more expensive than hydrogen mordenite

Synthesis and characterization of silver-polypyrrole film composite

Energy Technology Data Exchange (ETDEWEB)

Ayad, Mohamad M., E-mail: mayad12000@yahoo.com [Department of Chemistry, Faculty of Science, University of Tanta, Tanta (Egypt); Zaki, Eman [Department of Chemistry, Faculty of Science, University of Tanta, Tanta (Egypt)

2009-11-15

In this work, we report the chemical polymerization of pyrrole to obtain thin film of polypyrrole (PPy) hydrochloride deposited onto the electrode of the quartz crystal microbalance (QCM). The film in the base form was exposed to a solution of AgNO{sub 3}. Electroless reduction for silver ions by the PPy film took place and silver particles were adsorbed onto the film surface. The silver particles content at the PPy films were analyzed by QCM and the results showed that the concentrations of silver uptakes increase as the original AgNO{sub 3} solution increases. The morphology of the surface of the PPy film and the silver-PPy film composite were studied by the scanning electron microscopy (SEM) coupled with energy dispersive X-ray spectrometry (EDX). They showed that the obtained silver particles have spherical, cubic and tetrahedral structures. X-ray diffraction (XRD) and Fourier transformed infra-red spectroscopy (FTIR) were used to characterize the structure of the powder composite. This work reveals the capability of PPy film coating on QCM in sensing and removing silver from several environmental samples.

Synthesis and characterization of silver-polypyrrole film composite

International Nuclear Information System (INIS)

Ayad, Mohamad M.; Zaki, Eman

2009-01-01

In this work, we report the chemical polymerization of pyrrole to obtain thin film of polypyrrole (PPy) hydrochloride deposited onto the electrode of the quartz crystal microbalance (QCM). The film in the base form was exposed to a solution of AgNO 3 . Electroless reduction for silver ions by the PPy film took place and silver particles were adsorbed onto the film surface. The silver particles content at the PPy films were analyzed by QCM and the results showed that the concentrations of silver uptakes increase as the original AgNO 3 solution increases. The morphology of the surface of the PPy film and the silver-PPy film composite were studied by the scanning electron microscopy (SEM) coupled with energy dispersive X-ray spectrometry (EDX). They showed that the obtained silver particles have spherical, cubic and tetrahedral structures. X-ray diffraction (XRD) and Fourier transformed infra-red spectroscopy (FTIR) were used to characterize the structure of the powder composite. This work reveals the capability of PPy film coating on QCM in sensing and removing silver from several environmental samples.

Synthesis and characterization of silver-polypyrrole film composite

Science.gov (United States)

Ayad, Mohamad. M.; Zaki, Eman

2009-11-01

In this work, we report the chemical polymerization of pyrrole to obtain thin film of polypyrrole (PPy) hydrochloride deposited onto the electrode of the quartz crystal microbalance (QCM). The film in the base form was exposed to a solution of AgNO 3. Electroless reduction for silver ions by the PPy film took place and silver particles were adsorbed onto the film surface. The silver particles content at the PPy films were analyzed by QCM and the results showed that the concentrations of silver uptakes increase as the original AgNO 3 solution increases. The morphology of the surface of the PPy film and the silver-PPy film composite were studied by the scanning electron microscopy (SEM) coupled with energy dispersive X-ray spectrometry (EDX). They showed that the obtained silver particles have spherical, cubic and tetrahedral structures. X-ray diffraction (XRD) and Fourier transformed infra-red spectroscopy (FTIR) were used to characterize the structure of the powder composite. This work reveals the capability of PPy film coating on QCM in sensing and removing silver from several environmental samples.

Design, construction and test run of a solid adsorption solar refrigerator using activated carbon/methanol, as adsorbent/adsorbate pair

International Nuclear Information System (INIS)

Anyanwu, E.E.; Ezekwe, C.I.

2003-01-01

The design, construction and test run of a solid adsorption solar refrigerator are presented. It used activated carbon/methanol as the adsorbent/adsorbate pair. The refrigerator has three major components: collector/generator/adsorber, condenser and evaporator. Its flat plate type collector/generator/adsorber used clear plane glass sheet of effective exposed area of 1.2 m 2 . The steel condenser tube with a square plan view was immersed in pool of stagnant water contained in a reinforced sandcrete tank. The evaporator is a spirally coiled copper tube immersed in stagnant water. Adsorbent cooling during the adsorption process is both by natural convection of air over the collector plate and tubes and night sky radiation facilitated by removing the collector box end cover plates. Ambient temperatures during the adsorbate generation and adsorption process varied over 18.5-34 deg. C. The refrigerator yielded evaporator temperatures ranging over 1.0-8.5 deg. C from water initially in the temperature range 24-28 deg. C. Accordingly, the maximum daily useful cooling produced was 266.8 kJ/m 2 of collector area

Study on the adsorption performance of composite adsorbent of CaCl2 and expanded graphite with ammonia as adsorbate

International Nuclear Information System (INIS)

Li, S.L.; Wu, J.Y.; Xia, Z.Z.; Wang, R.Z.

2009-01-01

A novel constant volume test unit was built to study the adsorption performance of a new type composite adsorbent. This test unit can measure the adsorption isosteres of the working pairs. The adsorption isosteres are the curves of the adsorption pressure variation with the adsorption temperatures at constant adsorption quantities. Compared to the former test results of isothermals and isobars, the isosteres are better for the calculation of the adsorption heat, desorption heat and the selection the adsorption working pairs. Three experimental results were obtained: the first result was that the expanded graphite powders were superior to the expandable graphite powders to facilitate the transportation of working fluid in the composite adsorbent. The second one was that the composite adsorbent treated by solution is more homogeneous than the simple mixed composite adsorbent and the treated composite adsorbent has a better mass transfer performance. The last one was that the adsorption isosteres was the same one not only in the heating process but also in the cooling process and this performance was not relevant to the homogeneity of the composite adsorbent

Effect of surface microstructure and wettability on plasma protein adsorption to ZnO thin films prepared at different RF powers

Energy Technology Data Exchange (ETDEWEB)

Huang Zhanyun; Chen Min; Chen Dihu [State Key Laboratory of Optoelectronic Materials and Technologies, Sun Yat-Sen University, Guangzhou 510275 (China); Pan Shirong, E-mail: stscdh@mail.sysu.edu.c [Artificial Heart Lab, the 1st Affiliate Hospital of Sun Yat-Sen University, Guangzhou 510080 (China)

2010-10-01

In this paper, the adsorption behavior of plasma proteins on the surface of ZnO thin films prepared by radio frequency (RF) sputtering under different sputtering powers was studied. The microstructures and surface properties of the ZnO thin films were investigated by x-ray diffraction (XRD), scanning electron microscopy (SEM), UV-visible optical absorption spectroscopy and contact angle techniques. The results show that the ZnO thin films have better orientation of the (0 0 2) peak with increasing RF power, especially at around 160 W, and the optical band gap of the ZnO films varies from 3.2 to 3.4 eV. The contact angle test carried out by the sessile drop technique denoted a hydrophobic surface of the ZnO films, and the surface energy and adhesive work of the ZnO thin films decreased with increasing sputtering power. The amounts of human fibrinogen (HFG) and human serum albumin (HSA) adsorbing on the ZnO films and reference samples were determined by using enzyme-linked immunosorbent assay (ELISA). The results show that fewer plasma proteins and a smaller HFG/HSA ratio adsorb on the ZnO thin films' surface.

Eliminating Heavy Metals from Water with NanoSheet Minerals as Adsorbents

Directory of Open Access Journals (Sweden)

Shaoxian Song

2017-12-01

. Montmorillonite was usually pre-interacted with organics to increase the interlayer space, and then exfoliated to single or several layers by using ultrasonic. Among the nano-sheets, the surfaces are strongly charged negatively, while the edges are positively charged. This characteristic allows the adsorption of cations or anions, as well as the substances with negative or positive charges. Graphite can be oxidized and exfoliated into graphene oxide (GO, which has a huge specific surface area and plentiful of functional groups such as carboxyl, epoxy, carbonyl and hydroxyl, leading to high adsorption capacity to heavy metals in water. Nano-sheet molybdenite is a novel two-dimensional material with single or several layers of MoS2 sheets. The most common method to prepare nano-sheet molybdenite is exfoliated from bulk molybdenite through chemical method based on ion intercalation process. A large quantity of functional groups and S atom on the sheets are the active sites for adsorbing heavy metals in water. Nano-sheet minerals are used as adsorbents in the form of three-dimension hydrogels. They are featured by the huge specific surface area and high adsorption efficiency. In addition, the clean and smooth surfaces allow heavy metals to adsorb directly by film dispersion. Without any barrier of mesopores and micropores, the adsorption rate could be well improved. These characteristics would lead to the extremely large adsorption capacity and high adsorption rate. Currently, nano-sheet minerals as adsorbent is a very hot research topic in the field of heavy metal removal. It is expected that nanosheet minerals will be promising adsorbents in the removal of heavy metals from water.

Initial biocompatibility of plasma polymerized hexamethyldisiloxane films with different wettability

Science.gov (United States)

Krasteva, N. A.; Toromanov, G.; Hristova, K. T.; Radeva, E. I.; Pecheva, E. V.; Dimitrova, R. P.; Altankov, G. P.; Pramatarova, L. D.

2010-11-01

Understanding the relationships between material surface properties, behaviour of adsorbed proteins and cellular responses is essential to design optimal material surfaces for tissue engineering. In this study we modify thin layers of plasma polymerized hexamethyldisiloxane (PPHMDS) by ammonia treatment in order to increase surface wettability and the corresponding biological response. The physico-chemical properties of the polymer films were characterized by contact angle (CA) measurements and Fourier Transform Infrared Spectroscopy (FTIR) analysis.Human umbilical vein endothelial cells (HUVEC) were used as model system for the initial biocompatibility studies following their behavior upon preadsorption of polymer films with three adhesive proteins: fibronectin (FN), fibrinogen (FG) and vitronectin (VN). Adhesive interaction of HUVEC was evaluated after 2 hours by analyzing the overall cell morphology, and the organization of focal adhesion contacts and actin cytoskeleton. We have found similar good cellular response on FN and FG coated polymer films, with better pronounced vinculin expression on FN samples while. Conversely, on VN coated surfaces the wettability influenced significantly initial celular interaction spreading. The results obtained suggested that ammonia plasma treatment can modulate the biological activity of the adsorbed protein s on PPHMDS surfaces and thus to influence the interaction with endothelial cells.

Preparation of mesoporous silica thin films by photocalcination method and their adsorption abilities for various proteins

Energy Technology Data Exchange (ETDEWEB)

Kato, Katsuya, E-mail: katsuya-kato@aist.go.jp [National Institute of Advanced Industrial Science and Technology (AIST), 2266-98 Anagahora, Shimoshidami, Moriyama-ku, Nagoya 463-8560 (Japan); Nakamura, Hitomi [National Institute of Advanced Industrial Science and Technology (AIST), 2266-98 Anagahora, Shimoshidami, Moriyama-ku, Nagoya 463-8560 (Japan); Yamauchi, Yoshihiro; Nakanishi, Kazuma; Tomita, Masahiro [Department of Chemistry for Materials, Graduate School of Engineering, Mie University, 1577 Kurimamachiya-cho, Tsu, Mie 514-8570 (Japan)

2014-07-01

Mesoporous silica (MPS) thin film biosensor platforms were established. MPS thin films were prepared from tetraethoxysilane (TEOS) via using sol–gel and spin-coating methods using a poly-(ethylene oxide)-block-poly-(propylene oxide)-block-poly-(ethylene oxide) triblock polymer, such as P123 ((EO){sub 20}(PO){sub 70}(EO){sub 20}) or F127 ((EO){sub 106}(PO){sub 70}(EO){sub 106}), as the structure-directing agent. The MPS thin film prepared using P123 as the mesoporous template and treated via vacuum ultraviolet (VUV) irradiation to remove the triblock copolymer had a more uniform pore array than that of the corresponding film prepared via thermal treatment. Protein adsorption and enzyme-linked immunosorbent assay (ELISA) on the synthesized MPS thin films were also investigated. VUV-irradiated MPS thin films adsorbed a smaller quantity of protein A than the thermally treated films; however, the human immunoglobulin G (IgG) binding efficiency was higher on the former. In addition, protein A–IgG specific binding on MPS thin films was achieved without using a blocking reagent; i.e., nonspecific adsorption was inhibited by the uniform pore arrays of the films. Furthermore, VUV-irradiated MPS thin films exhibited high sensitivity for ELISA testing, and cytochrome c adsorbed on the MPS thin films exhibited high catalytic activity and recyclability. These results suggest that MPS thin films are attractive platforms for the development of novel biosensors. - Highlights: • VUV-treated MPS thin films with removed polymer had uniform pore. • VUV-treated MPS thin films exhibited high sensitivity by ELISA. • Cytochrome c showed the catalytic activity and recyclability on synthesized films.

Preparation of mesoporous silica thin films by photocalcination method and their adsorption abilities for various proteins

International Nuclear Information System (INIS)

Kato, Katsuya; Nakamura, Hitomi; Yamauchi, Yoshihiro; Nakanishi, Kazuma; Tomita, Masahiro

2014-01-01

Mesoporous silica (MPS) thin film biosensor platforms were established. MPS thin films were prepared from tetraethoxysilane (TEOS) via using sol–gel and spin-coating methods using a poly-(ethylene oxide)-block-poly-(propylene oxide)-block-poly-(ethylene oxide) triblock polymer, such as P123 ((EO) 20 (PO) 70 (EO) 20 ) or F127 ((EO) 106 (PO) 70 (EO) 106 ), as the structure-directing agent. The MPS thin film prepared using P123 as the mesoporous template and treated via vacuum ultraviolet (VUV) irradiation to remove the triblock copolymer had a more uniform pore array than that of the corresponding film prepared via thermal treatment. Protein adsorption and enzyme-linked immunosorbent assay (ELISA) on the synthesized MPS thin films were also investigated. VUV-irradiated MPS thin films adsorbed a smaller quantity of protein A than the thermally treated films; however, the human immunoglobulin G (IgG) binding efficiency was higher on the former. In addition, protein A–IgG specific binding on MPS thin films was achieved without using a blocking reagent; i.e., nonspecific adsorption was inhibited by the uniform pore arrays of the films. Furthermore, VUV-irradiated MPS thin films exhibited high sensitivity for ELISA testing, and cytochrome c adsorbed on the MPS thin films exhibited high catalytic activity and recyclability. These results suggest that MPS thin films are attractive platforms for the development of novel biosensors. - Highlights: • VUV-treated MPS thin films with removed polymer had uniform pore. • VUV-treated MPS thin films exhibited high sensitivity by ELISA. • Cytochrome c showed the catalytic activity and recyclability on synthesized films

Adsorbent catalytic nanoparticles and methods of using the same

Energy Technology Data Exchange (ETDEWEB)

Slowing, Igor Ivan; Kandel, Kapil

2017-01-31

The present invention provides an adsorbent catalytic nanoparticle including a mesoporous silica nanoparticle having at least one adsorbent functional group bound thereto. The adsorbent catalytic nanoparticle also includes at least one catalytic material. In various embodiments, the present invention provides methods of using and making the adsorbent catalytic nanoparticles. In some examples, the adsorbent catalytic nanoparticles can be used to selectively remove fatty acids from feedstocks for biodiesel, and to hydrotreat the separated fatty acids.

Hybrid Films Based on a Bridged Silsesquioxane Doped with Goethite and Montmorillonite Nanoparticles as Sorbents of Wastewater Contaminants

Directory of Open Access Journals (Sweden)

Carolina V. Waiman

2016-01-01

Full Text Available The synthesis and characterization of silsesquioxane (SSO films with pendant dodecyl groups and doped with goethite (Gt or montmorillonite (MMT nanoparticles were carried out and the new materials tested as sorbents of diverse contaminants. The synthetic method used yielded SSO films with the inorganic substrates homogeneously distributed within the polymeric matrices. The new materials were characterized by SEM, FTIR, XRD, and DSC and tested to evaluate their capability for adsorbing metallic cations, organic dyes, and phosphate, frequent contaminants of industrial effluents. All films were found suitable for removing metallic cations. Results also showed that the SSO films undoped and doped with Gt are primarily apt for anionic compounds removal. Although the SSO films doped with MMT are capable of removing cationic contaminants from aqueous samples, the stiffness of the SSO matrix hinders MMT properties as an adsorbent. The possibility of dispersing nanoparticulate systems in the stable and chemically inert SSO matrices simplifies their application for contaminant removal, particularly because it makes the separation process of the absorbed pollutant from the treated medium easier.

The metrics of surface adsorbed small molecules on the Young's fringe dual-slab waveguide interferometer

International Nuclear Information System (INIS)

Cross, Graham H; Reeves, Andrew; Brand, Stuart; Swann, Marcus J; Peel, Louise L; Freeman, Neville J; Lu, Jian R

2004-01-01

A method for analysing thin films using a dual-waveguide interferometric technique is described. Alternate dual polarization addressing of the interferometer sensor using a ferroelectric liquid crystal polarization switch allowed the opto-geometrical properties (density and thickness) of adsorbed layers at a solid-liquid interface to be determined. Differences in the waveguide mode dispersion between the transverse electric and transverse magnetic modes allowed unique combinations of layer thickness and refractive index to be determined at all stages of the layer formation process. The technique has been verified by comparing the analysis of the surface adsorption of surfactants with data obtained using neutron scattering techniques, observing their behaviour on trimethylsilane coated silicon oxynitride surfaces. The data obtained were found to be in excellent agreement with analogous neutron scattering experiments and the precision of the measurements taken to be of the order of 40 pm with respect to adsorbed layer thicknesses. The study was extended to a series of surfactants whose layer morphology could be correlated with their hydrophilicity/lipophilicity balance. Those in the series with longer alkyl chains were observed to form thinner, denser layers at the hydrophobic solid/aqueous liquid interface and the degree of order attained at sub-critical micelle concentrations to be correlated with molecular fluidity. The technique is expected to find utility with those interested in thin film analysis. An important and growing area of application is within the life sciences, especially in the field of protein structure and function

Unraveling the Dynamics of Nanoscopically Confined PVME in Thin Films of a Miscible PVME/PS Blend.

Science.gov (United States)

Madkour, Sherif; Szymoniak, Paulina; Radnik, Jörg; Schönhals, Andreas

2017-10-25

Broadband dielectric spectroscopy (BDS) was employed to investigate the glassy dynamics of thin films (7-200 nm) of a poly(vinyl methyl ether) (PVME)/polystyrene (PS) blend (50:50 wt %). For BDS measurements, nanostructured capacitors (NSCs) were employed, where films are allowed a free surface. This method was applied for film thicknesses up to 36 nm. For thicker films, samples were prepared between crossed electrode capacitors (CECs). The relaxation spectra of the films showed multiple processes. The first process was assigned to the α-relaxation of a bulklike layer. For films measured by NSCs, the rates of α-relaxation were higher compared to those of the bulk blend. This behavior was related to the PVME-rich free surface layer at the polymer/air interface. The second process was observed for all films measured by CECs (process X) and the 36 nm film measured by NSCs (process X2). This process was assigned to fluctuations of constraint PVME segments by PS. Its activation energy was found to be thickness-dependent because of the evidenced thickness dependency of the compositional heterogeneity. Finally, a third process with an activated temperature dependence was observed for all films measured by NSCs (process X1). It resembled the molecular fluctuations in an adsorbed layer found for thin films of pure PVME, and thus, it is assigned accordingly. This process undergoes an extra confinement because of frozen adsorbed PS segments at the polymer/substrate interface. To our knowledge, this is the first example where confinement-induced changes were observed by BDS for blend thin films.

Investigation of A-3 adsorbent-ditolylmethane two-phase system

International Nuclear Information System (INIS)

Ermakov, V.A.; Benderskaya, O.S.

1988-01-01

Compatibility of A-3 adsorbent, produced on the basis of palygoskite clay, with organic coolant of nuclear reactors-ditolylmethane (DTM)- and the possibility to use the given adsorbent for DTM purification from surfactant impurities are investigated. Compatibility of the adsorbent with DTM was evaluated by the concentration of its constituents in liquid phase. Sufactant adsorption was observed by the change in acid number of coolant, optical density at λ=396 nm and adsorbate mass in the adsorbent. From spent adsorbent the coolant was washed out by n-heptane, and the adsorbate - by methylene chloride, othanol and water in succession. On the basis of the results obtained the conclusion is made that A3 possesses a high chemical stability in DTM medium, i.e. it is compatible with DTM and can be used for its purification from surfactant impurities sorbed on heat-transferring surface

Irradiation Degradation of Adsorbents for Minor Actinides Recovery

International Nuclear Information System (INIS)

Watanabe, S.; Sano, Y.; Kofuji, H.; Takeuchi, M.; Koizumi, T.

2015-01-01

Extraction chromatography is one of the promising technologies for minor actinides (MA: Am and Cm) recovery from high-level liquid waste. The degradation behaviour of the organic species in the adsorbents under radiation exposure is important to discuss the safety and durability of the adsorbent in the extraction chromatography process. In this study, gamma-ray irradiation experiments on TODGA/SiO 2 -P adsorbent were carried out to investigate the degradation products from radiolysis of the adsorbent. The degraded organic species eluted from the adsorbent and those remaining inside the adsorbent were thoroughly identified by GC/MS, FT-IR and NMR analyses. The species suspected as hydrolysis products of TODGA were mainly detected from the analyses. Since some radicals such as.H or.OH are generated by the gamma-ray irradiation on water molecules, it was discussed that the radicals products from radiolysis of HNO 3 solution are related to the degradation reaction of the extractants. (authors)

Investigations Into the Reusability of Amidoxime-Based Polymeric Uranium Adsorbents

Energy Technology Data Exchange (ETDEWEB)

Kuo, Li-Jung [Pacific Northwest National Lab. (PNNL), Sequim, WA (United States). Marine Science Lab.; Gill, Gary A. [Pacific Northwest National Lab. (PNNL), Sequim, WA (United States). Marine Science Lab.; Strivens, Jonathan E. [Pacific Northwest National Lab. (PNNL), Sequim, WA (United States). Marine Science Lab.; Wood, Jordana R. [Pacific Northwest National Lab. (PNNL), Sequim, WA (United States). Marine Science Lab.; Schlafer, Nicholas J. [Pacific Northwest National Lab. (PNNL), Sequim, WA (United States). Marine Science Lab.; Wai, Chien M. [Univ. of Idaho, Moscow, ID (United States); LCW Supercritical Technologies, Seattle, WA (United States); Pan, H. B. [Univ. of Idaho, Moscow, ID (United States)

2016-09-28

Significant advancements in amidoxime-based polymeric adsorbents to extract uranium from seawater are achieved in recent years. The success of uranium adsorbent development can help provide a sustainable supply of fuel for nuclear reactors. To bring down the production cost of this new technology, in addition to the development of novel adsorbents with high uranium capacity and manufacture cost, the development of adsorbent re-using technique is critical because it can further reduce the cost of the adsorbent manufacture. In our last report, the use of high concentrations of bicarbonate solution (3M KHCO3) was identified as a cost-effective, environmental friendly method to strip uranium from amidoxime-based polymeric adsorbents. This study aims to further improve the method for high recovery of uranium capacity in re-uses and to evaluate the performance of adsorbents after multiple re-use cycles. Adsorption of dissolved organic matter (DOM) on the uranium adsorbents during seawater exposure can hinder the uranium adsorption and slow down the adsorption rate. An additional NaOH rinse (0.5 M NaOH, room temperature) was applied after the 3 M KHCO3 elution to remove natural organic matter from adsorbents. The combination of 3 M KHCO3 elution and 0.5 M NaOH rinse significantly improves the recovery of uranium adsorption capacity in the re-used adsorbents. In the first re-use, most ORNL adsorbents tested achieve ~100% recovery by using 3 M KHCO3 elution + 0.5 M NaOH rinse approach, in comparison to 54% recovery when only 3 M KHCO3 elution was applied. A significant drop in capacity was observed when the adsorbents went through more than one re-use. FTIR spectra revealed that degradation of amidoxime ligands occurs during seawater exposure, and is more significant the longer the exposure time. Significantly elevated ratios of Ca/U and Mg/U in re-used adsorbents support the decrease in abundance of amidoxime ligands and increase carboxylate group from FT-IR analysis. The

Diffuse Scattering of the Conduction Electrons of a Metallic Substrate by an Adsorbate: an Experimental Study Using Synchrotron Infrared Radiation

International Nuclear Information System (INIS)

Hein, M.; Otto, A.; Dumas, P.; Williams, G. P.

1999-01-01

Due to its intrinsic high brightness, high stability, and proportionality to the stored electron beam current, synchrotrons IR spectroscopy has revealed itself as an unique tool to experimentally test a physical phenomenon occurring at metallic interfaces, the theory for which was motivated by previous observations. Any adsorbate induces inelastic scattering of the conduction electrons, which causes a broadband IR reflectance change, and was predicted to induce a concomitant DC resistivity change. By choosing a well ordered single crystal thin film of Cu(111), we have checked that the DC resistivity change, and the asymptotic limit of the IR reflectance change are linearly dependent, but independent of the nature of the adsorbate. Coadsorption experiments which have been used to modify the induced density of states at the Fermi level, have further demonstrated that the friction coefficient, which is responsible for the elastic scattering phenomenon, is chemically specific. This article describes the use of synchrotron radiation as an absolute source and its application to the study of dynamics of adsorbates on surfaces

Functional Layer-by-Layer Thin Films of Inducible Nitric Oxide (NO) Synthase Oxygenase and Polyethylenimine: Modulation of Enzyme Loading and NO-Release Activity.

Science.gov (United States)

Gunasekera, Bhagya; Abou Diwan, Charbel; Altawallbeh, Ghaith; Kalil, Haitham; Maher, Shaimaa; Xu, Song; Bayachou, Mekki

2018-03-07

Nitric oxide (NO) release counteracts platelet aggregation and prevents the thrombosis cascade in the inner walls of blood vessels. NO-release coatings also prevent thrombus formation on the surface of blood-contacting medical devices. Our previous work has shown that inducible nitric oxide synthase (iNOS) films release NO fluxes upon enzymatic conversion of the substrate l-arginine. In this work, we report on the modulation of enzyme loading in layer-by-layer (LbL) thin films of inducible nitric oxide synthase oxygenase (iNOSoxy) on polyethylenimine (PEI). The layer of iNOSoxy is electrostatically adsorbed onto the PEI layer. The pH of the iNOSoxy solution affects the amount of enzyme adsorbed. The overall negative surface charge of iNOSoxy in solution depends on the pH and hence determines the density of adsorbed protein on the positively charged PEI layer. We used buffered iNOSoxy solutions adjusted to pHs 8.6 and 7.0, while saline PEI solution was used at pH 7.0. Atomic force microscopy imaging of the outermost layer shows higher protein adsorption with iNOSoxy at pH 8.6 than with a solution of iNOSoxy at pH 7.0. Graphite electrodes with PEI/iNOSoxy films show higher catalytic currents for nitric oxide reduction mediated by iNOSoxy. The higher enzyme loading translates into higher NO flux when the enzyme-modified surface is exposed to a solution containing the substrate and a source of electrons. Spectrophotometric assays showed higher NO fluxes with iNOSoxy/PEI films built at pH 8.6 than with films built at pH 7.0. Fourier transform infrared analysis of iNOSoxy adsorbed on PEI at pH 8.6 and 7.0 shows structural differences of iNOSoxy in films, which explains the observed changes in enzymatic activity. Our findings show that pH provides a strategy to optimize the NOS loading and enzyme activity in NOS-based LbL thin films, which enables improved NO release with minimum layers of PEI/NOS.

Calcinated tea and cellulose composite films and its dielectric and lead adsorption properties.

Science.gov (United States)

Jayaramudu, Tippabattini; Varaprasad, Kokkarachedu; Kim, Hyun Chan; Kafy, Abdullahil; Kim, Jung Woong; Kim, Jaehwan

2017-09-01

In this paper, calcinated tea and cellulose composite (CTCC) films were fabricated via solution casting method. Chemical structure, morphology, crystallinity and thermal stability of the fabricated films were characterized by using Fourier transform infrared spectroscopy, scanning electron microscopy, X-ray diffraction and thermogravimetric analysis. The effect of calcinated tea loading on the properties of the prepared CTCC films was studied. The results suggest that the prepared CTCC films show higher mechanical properties, thermal stability and dielectric constant than the neat cellulose film. In addition, the CTCC films adsorb Pb 2+ ions and its adsorption performance depends on the calcinated tea content and pH level. The CTCC films are useful for sensors, flexible capacitor as well as lead adsorption applications. Copyright © 2017 Elsevier Ltd. All rights reserved.

Processing method and device for iodine adsorbing material

International Nuclear Information System (INIS)

Watanabe, Shin-ichi; Shiga, Reiko.

1997-01-01

An iodine adsorbing material adsorbing silver compounds is reacted with a reducing gas, so that the silver compounds are converted to metal silver and stored. Then, the silver compounds are not melted or recrystallized even under a highly humid condition, accordingly, peeling of the adsorbed materials from a carrier can be prevented, and the iodine adsorbing material can be stored stably. Since the device is disposed in an off gas line for discharging off gases from a nuclear power facility, the iodine adsorbing material formed by depositing silver halides to the carrier is contained, and a reducing or oxidizing gas is supplied to the vessel as required, and silver halides can be converted to metal silver or the metal silver can be returned to silver halide. (T.M.)

Regenerative adsorbent heat pump

Science.gov (United States)

Jones, Jack A. (Inventor)

1991-01-01

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.

Strong adsorption characteristics of a novel overoxidized poly(3,4-ethylenedioxythiophene) film and application for dopamine sensing

International Nuclear Information System (INIS)

Lin, Jia-Min; Su, Ya-Ling; Chang, Wei-Ting; Su, Wan-Yu; Cheng, Shu-Hua

2014-01-01

Highlights: • A novel overoxidized poly(3,4-ethylenedioxythiophene) film is obtained. • The film structure favors the adsorption of dopamine. • The sensor is able to detect dopamine in the presence of ascorbic acid (1000X). - Abstract: An overoxidized poly(3,4-ethylenedioxythiophene) film-modified screen-printed carbon electrodes (SPCE/PEDOT ox ) was prepared and characterized by field emission scanning electron microscopy (FE-SEM), X-ray photoelectron spectroscopy (XPS) and water contact angle techniques. The obtained film is a porous structure with highly abundant oxygen functionality. The SPCE/PEDOT ox could adsorb cations strongly and perform catalytic oxidation of biomolecules. The potential-induced adsorption of dopamine was observed for SPCE/PEDOT ox . A simple medium-exchange procedure was developed for the selective determination of dopamine by the use of the dopamine-adsorbed electrode. Under optimal differential pulse voltammetry (DPV), the proposed assay can be employed in the determination of submicromolar concentration of dopamine without the coexisting interferences of ascorbic acid (1000-fold) and uric acid (10-fold)

Humidity sensing properties of WO3 thick film resistor prepared by screen printing technique

International Nuclear Information System (INIS)

Garde, Arun S

2014-01-01

Highlights: • Polycrystalline WO 3 Thick films are fabricated by screen printing technique. • Monoclinic phases were the majority in formation of films. • The peak at 1643 cm −1 shows stretching vibrations attributed to W-OH of adsorbed H 2 O. • Absorption peaks in the range 879–650 cm −1 are attributed to the stretching W-O-W bonds. • Increase in resistance with decrease in RH when exposed to 20–100% RH. - Abstract: Thick films of tungsten oxide based were prepared using standard screen printing technique. To study the effect of temperature on the thick films were fired at different temperature for 30 min in air atmosphere. The WO 3 thick films were characterized with X-ray diffraction, scanning electron microscopy and EDAX for elemental analysis. The formation of mixed phases of the film together with majority of monoclinic phase was observed. IR spectra confirm the peak at 1643 cm −1 clearly shows stretching vibrations attributed to the W-OH bending vibration mode of the adsorbed water molecules. The absorption peaks in the range 879–650 cm −1 are attributed to the stretching W-O-W bonds (i.e. ν [W-O inter -W]). The peak located at 983 cm −1 belong to W=O terminal of cluster boundaries. A change in the resistance was observed with respect to the relative humidity when the WO 3 thick films were exposed to a wide humidity range of 20–100%. An increasing firing temperature of WO 3 film increases with the sensitivity. The parameters such as sensitivity and hysteresis of the WO 3 film sensors have been evaluated

Study of the Adsorbent-Adsorbate Interactions from Cd(II) and Pb(II) Adsorption on Activated Carbon and Activated Carbon Fiber

Energy Technology Data Exchange (ETDEWEB)

Kim, Dae Ho; Kim, Doo Won; Kim, Bohye; Yang, Kap Seung [Chonnam National Univ., Gwangju (Korea, Republic of); Lim, Yongkyun; Park, Eun Nam [Microfilter Co., Ltd, Seoul (Korea, Republic of)

2013-02-15

The adsorption characteristics of Cd(II) and Pb(II) in aqueous solution using granular activated carbon (GAC), activated carbon fiber (ACF), modified ACF (NaACF), and a mixture of GAC and NaACF (GAC/NaACF) have been studied. The surface properties, such as morphology, surface functional groups, and composition of various adsorbents were determined using X-ray photoelectron spectroscopy (XPS) and scanning electron microscopy (SEM) measurements. The specific surface area, total pore volume, and pore size distribution were investigated using nitrogen adsorption, Brunauer-Emmett-Teller (BET), and Barrett-Joyner-Halenda (BJH) methods. In this study, NaACF showed a high adsorption capacity and rate for heavy metal ions due to the improvement of its ion-exchange capabilities by additional oxygen functional groups. Moreover, the GAC and NaACF mixture was used as an adsorbent to determine the adsorbent-adsorbate interaction in the presence of two competitive adsorbents.

Study of the Adsorbent-Adsorbate Interactions from Cd(II) and Pb(II) Adsorption on Activated Carbon and Activated Carbon Fiber

International Nuclear Information System (INIS)

Kim, Dae Ho; Kim, Doo Won; Kim, Bohye; Yang, Kap Seung; Lim, Yongkyun; Park, Eun Nam

2013-01-01

The adsorption characteristics of Cd(II) and Pb(II) in aqueous solution using granular activated carbon (GAC), activated carbon fiber (ACF), modified ACF (NaACF), and a mixture of GAC and NaACF (GAC/NaACF) have been studied. The surface properties, such as morphology, surface functional groups, and composition of various adsorbents were determined using X-ray photoelectron spectroscopy (XPS) and scanning electron microscopy (SEM) measurements. The specific surface area, total pore volume, and pore size distribution were investigated using nitrogen adsorption, Brunauer-Emmett-Teller (BET), and Barrett-Joyner-Halenda (BJH) methods. In this study, NaACF showed a high adsorption capacity and rate for heavy metal ions due to the improvement of its ion-exchange capabilities by additional oxygen functional groups. Moreover, the GAC and NaACF mixture was used as an adsorbent to determine the adsorbent-adsorbate interaction in the presence of two competitive adsorbents

Adsorption of quantum dots onto polymer and Gemini surfactant films: a quartz crystal microbalance study.

Science.gov (United States)

Alejo, T; Merchán, M D; Velázquez, M M

2014-08-26

We used quartz crystal microbalance with dissipation to study the mechanical properties, the kinetics of adsorption, and the amount of CdSe quantum dots (QDs) adsorbed onto a SiO2 sensor, referred as bare sensor, onto the sensor modified with a film of the polymer poly(maleic anhydride-alt-1-octadecene), PMAO, or with a film of the Gemini surfactant ethyl-bis(dimethyl octadecyl ammonium bromide), abbreviated as 18-2-18. Results showed that when the sensor is coated with polymer or surfactant molecules, the coverage increases compared with that obtained for the bare sensor. On the other hand, rheological properties and kinetics of adsorption of QDs are driven by QD nanoparticles. Thus, the QD films present elastic behavior, and the elasticity values are independent of the molecule used as coating and similar to the elasticity value obtained for QDs films on the bare sensor. The QD adsorption is a two-step mechanism in which the fastest process is attributed to the QD adsorption onto the solid substrate and the slowest one is ascribed to rearrangement movements of the nanoparticles adsorbed at the surface.

Phase behavior of mixed submonolayer films of krypton and xenon on graphite.

Science.gov (United States)

Patrykiejew, A; Sokołowski, S

2012-04-14

Using the results of extensive Monte Carlo simulations in the canonical and grand canonical ensembles, we discuss the phase behavior of mixed submonolayer films of krypton and xenon adsorbed on the graphite basal plane. The calculations have been performed using two- and three-dimensional models of the systems studied. It has been demonstrated that out-of-plane motion does not affect the properties of the films as long as the total density is well below the monolayer completion and at moderate temperatures. For the total densities close to the monolayer completion, the promotion of particles to the second layer considerably affects the film properties. Our results are in a reasonable agreement with the available experimental data. The melting point of submonolayer films has been shown to exhibit non-monotonous changes with the film composition, and reaches minimum for the xenon concentration of about 50%. At the temperatures below the melting point, the structure of solid phases depends upon the film composition and the temperature; one can also distinguish commensurate and incommensurate phases. Two-dimensional calculations have demonstrated that for the xenon concentration between about 15% and 65% the adsorbed film exhibits the formation of a superstructure, in which each Xe atom is surrounded by six Kr atoms. This superstructure is stable only at very low temperatures and transforms into the mixed commensurate (√3×√3)R30° phase upon the increase of temperature. Such a superstructure does not appear when a three-dimensional model is used. Grand canonical ensemble calculations allowed us to show that for the xenon concentration of about 3% the phase diagram topology of monolayer films changes from the krypton-like (with incipient triple point) to the xenon-like (with ordinary triple point).

Chitin Adsorbents for Toxic Metals: A Review

Directory of Open Access Journals (Sweden)

Ioannis Anastopoulos

2017-01-01

Full Text Available Wastewater treatment is still a critical issue all over the world. Among examined methods for the decontamination of wastewaters, adsorption is a promising, cheap, environmentally friendly and efficient procedure. There are various types of adsorbents that have been used to remove different pollutants such as agricultural waste, compost, nanomaterials, algae, etc., Chitin (poly-β-(1,4-N-acetyl-d-glucosamine is the second most abundant natural biopolymer and it has attracted scientific attention as an inexpensive adsorbent for toxic metals. This review article provides information about the use of chitin as an adsorbent. A list of chitin adsorbents with maximum adsorption capacity and the best isotherm and kinetic fitting models are provided. Moreover, thermodynamic studies, regeneration studies, the mechanism of adsorption and the experimental conditions are also discussed in depth.

Growth and hydrogenation of ultra-thin Mg films on Mo(111)

DEFF Research Database (Denmark)

Ostenfeld, Christopher Worsøe; Davies, Jonathan Conrad; Vegge, Tejs

2005-01-01

. Hydrogen cannot be adsorbed on magnesium films under UHV conditions. However, when evaporating Mg in a hydrogen background, a hydrogen overlayer is seen to adsorb at the Mg surface, due to the catalytic interaction with the Mo(1 1 1) substrate and subsequent spill-over. We show that two monolayers of Mg......The growth and hydrogenation of ultra-thin magnesium overlayers have been investigated on a Mo(1 1 1) single crystal substrate. For increasing magnesium coverages we observe intermediate stages in the TPD and LEISS profiles, which illustrate the transition from one monolayer to multilayer growth...

An in situ XPS study of L-cysteine co-adsorbed with water on polycrystalline copper and gold

Science.gov (United States)

Jürgensen, Astrid; Raschke, Hannes; Esser, Norbert; Hergenröder, Roland

2018-03-01

The interactions of biomolecules with metal surfaces are important because an adsorbed layer of such molecules introduces complex reactive functionality to the substrate. However, studying these interactions is challenging: they usually take place in an aqueous environment, and the structure of the first few monolayers on the surface is of particular interest, as these layers determine most interfacial properties. Ideally, this requires surface sensitive analysis methods that are operated under ambient conditions, for example ambient pressure x-ray photoelectron spectroscopy (AP-XPS). This paper focuses on an AP-XPS study of the interaction of water vapour and l-Cysteine on polycrystalline copper and gold surfaces. Thin films of l-Cysteine were characterized with XPS in UHV and in a water vapour atmosphere (P ≤ 1 mbar): the structure of the adsorbed l-Cysteine layer depended on substrate material and deposition method, and exposure of the surface to water vapour led to the formation of hydrogen bonds between H2O molecules and the COO- and NH2 groups of adsorbed l-Cysteine zwitterions and neutral molecules, respectively. This study also proved that it is possible to investigate monolayers of biomolecules in a gas atmosphere with AP-XPS using a conventional laboratory Al-Kα x-ray source.

Molecular sieve adsorbents and membranes for applications in the production of renewable fuels and chemicals

Science.gov (United States)

Ranjan, Rajiv

Metal organic frameworks (MOF), a new class of porous materials, have emerged as promising candidate for gas storage, separation membrane and chemical sensors. We used secondary growth method to grow microporous metal organic framework (MMOF) films on porous alumina supports. Examination of the film using SEM and XRD showed that the crystals were well inter-grown and preferentially oriented. Gas permeation study showed that membranes were defect free and moderate selectivity was achieved for H2/N2 gas pairs. The next project had to do with ethanol production from lignocellulosic biomass as an alternate energy source. However, toxic inhibitors produced from the hydrolysis of biomass decrease ethanol yield during the fermentation process. We demonstrated the use of zeolites for the pretreatment of hydrolyzate in order to remove inhibitors like 5-Hydroxymethylfurfuraldehyde (HMF) and furfural from aqueous solution. Zeolites exhibit preferential adsorption of the inhibitors and in effect improve the ethanol yield during fermentation. Ideal Adsorbed Solution Theory (IAST) was also used to predict adsorption isotherms for HMF-furfural mixtures using single component adsorption data. We also studied production of HMF, a potential substitute as a building block for plastic and chemical production, from renewable biomass resources. Catalytic dehydration of fructose for HMF production faces problems like low conversion and yield. Dimethyl sulfoxide (DMSO) can be used as the solvent as well as the catalyst resulting in high HMF yield. We studied a reaction-separation system for this dehydration reaction where the product (HMF) could be recovered by selective adsorption on solid adsorbents from the reaction mixture.

Nano-sized Adsorbate Structure Formation in Anisotropic Multilayer System

Science.gov (United States)

Kharchenko, Vasyl O.; Kharchenko, Dmitrii O.; Yanovsky, Vladimir V.

2017-05-01

In this article, we study dynamics of adsorbate island formation in a model plasma-condensate system numerically. We derive the generalized reaction-diffusion model for adsorptive multilayer system by taking into account anisotropy in transfer of adatoms between neighbor layers induced by electric field. It will be found that with an increase in the electric field strength, a structural transformation from nano-holes inside adsorbate matrix toward separated nano-sized adsorbate islands on a substrate is realized. Dynamics of adsorbate island sizes and corresponding distributions are analyzed in detail. This study provides an insight into details of self-organization of adatoms into nano-sized adsorbate islands in anisotropic multilayer plasma-condensate systems.

Flow boundary conditions for chain-end adsorbing polymer blends.

Science.gov (United States)

Zhou, Xin; Andrienko, Denis; Delle Site, Luigi; Kremer, Kurt

2005-09-08

Using the phenol-terminated polycarbonate blend as an example, we demonstrate that the hydrodynamic boundary conditions for a flow of an adsorbing polymer melt are extremely sensitive to the structure of the epitaxial layer. Under shear, the adsorbed parts (chain ends) of the polymer melt move along the equipotential lines of the surface potential whereas the adsorbed additives serve as the surface defects. In response to the increase of the number of the adsorbed additives the surface layer becomes thinner and solidifies. This results in a gradual transition from the slip to the no-slip boundary condition for the melt flow, with a nonmonotonic dependence of the slip length on the surface concentration of the adsorbed ends.

Membrane adsorber for endotoxin removal

Directory of Open Access Journals (Sweden)

Karina Moita de Almeida

Full Text Available ABSTRACT The surface of flat-sheet nylon membranes was modified using bisoxirane as the spacer and polyvinyl alcohol as the coating polymer. The amino acid histidine was explored as a ligand for endotoxins, aiming at its application for endotoxin removal from aqueous solutions. Characterization of the membrane adsorber, analysis of the depyrogenation procedures and the evaluation of endotoxin removal efficiency in static mode are discussed. Ligand density of the membranes was around 7 mg/g dry membrane, allowing removal of up to 65% of the endotoxins. The performance of the membrane adsorber prepared using nylon coated with polyvinyl alcohol and containing histidine as the ligand proved superior to other membrane adsorbers reported in the literature. The lack of endotoxin adsorption on nylon membranes without histidine confirmed that endotoxin removal was due to the presence of the ligand at the membrane surface. Modified membranes were highly stable, exhibiting a lifespan of approximately thirty months.

Combination of rice husk and coconut shell activated adsorbent to adsorb Pb(II) ionic metal and it’s analysis using solid-phase spectrophotometry (sps)

Science.gov (United States)

Rohmah, D. N.; Saputro, S.; Masykuri, M.; Mahardiani, L.

2018-03-01

The purpose of this research was to know the effect and determine the mass comparation which most effective combination between rice husk and coconut shell activated adsorbent to adsorb Pb (II) ion using SPS method. This research used experimental method. Technique to collecting this datas of this research is carried out by several stages, which are: (1) carbonization of rice husk and coconut shell adsorbent using muffle furnace at a temperature of 350°C for an hour; (2) activation of the rice husk and coconut shell adsorbent using NaOH 1N and ZnCl2 15% activator; (3) contacting the adsorbent of rice husk and coconut shell activated adsorbent with liquid waste simulation of Pb(II) using variation comparison of rice husk and coconut shell, 1:0; 0:1; 1:1; 2:1; 1:2; (4) analysis of Pb(II) using Solid-Phase Spectrophotometry (SPS); (5) characterization of combination rice husk and coconut shell activated adsorbent using FTIR. The result of this research show that the combined effect of combination rice husk and coconut shell activated adsorbent can increase the ability of the adsorbent to absorb Pb(II) ion then the optimum adsorbent mass ratio required for absorbing 20 mL of Pb(II) ion with a concentration of 49.99 µg/L is a ratio of 2:1 with the absorption level of 97,06%Solid-Phase Spectrophotometry (SPS) is an effective method in the level of µg/L, be marked with the Limit of Detection (LOD) of 0.03 µg/L.

Removal of adsorbent particles od copper ions by Jet flotation

International Nuclear Information System (INIS)

Santander, M.; Tapia, P.; Pavez, O.; Valderrama, L.; Guzman, D.

2009-01-01

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.

Interference Effects in the Optical Second Harmonic Generation from Ultrathin Alkali Films

DEFF Research Database (Denmark)

Balzer, F.; Rubahn, Horst-Günter

2000-01-01

Interference effects are shown to strongly modulate the transmission second harmonic signal (fundamental wavelength 1067 nm) from rough alkali island films grown on insulating substrates if one varies the angle of incidence. Depending on growth conditions and substrate thickness, the measured...... second harmonic dependencies can be interpreted in terms of interference between frontside and rearside adsorbed islands or by taking into account the morphology of the adsorbed alkali islands. By the use of different polarization combinations of both pump and reflected second harmonic wave we obtain...... accurate values of the ratios of the relevant nonlinear optical coefficients....

Solvent vapor annealing in the molecular regime drastically improves carrier transport in small-molecule thin-film transistors

KAUST Repository

Khan, Hadayat Ullah

2013-04-10

We demonstrate a new way to investigate and control the solvent vapor annealing of solution-cast organic semiconductor thin films. Solvent vapor annealing of spin-cast films of 6,13-bis(triisopropylsilylethynyl) pentacene (TIPS-Pn) is investigated in situ using quartz crystal microbalance with dissipation (QCM-D) capability, allowing us to monitor both solvent mass uptake and changes in the mechanical rigidity of the film. Using time-resolved grazing incidence wide angle X-ray scattering (GIWAXS) and complementary static atomic force microscopy (AFM), we demonstrate that solvent vapor annealing in the molecular regime can cause significant performance improvements in organic thin film transistors (OTFTs), whereas allowing the solvent to percolate and form a liquid phase results in catastrophic reorganization and dewetting of the film, making the process counterproductive. Using these lessons we devise processing conditions which prevent percolation of the adsorbed solvent vapor molecules for extended periods, thus extending the benefits of solvent vapor annealing and improving carrier mobility by nearly two orders of magnitude. Ultimately, it is demonstrated that QCM-D is a very powerful sensor of the state of the adsorbed solvent as well as the thin film, thus making it suitable for process development as well as in-line process monitoring both in laboratory and in future manufacturing settings. © 2013 American Chemical Society.

Solvent vapor annealing in the molecular regime drastically improves carrier transport in small-molecule thin-film transistors

KAUST Repository

Khan, Hadayat Ullah; Li, Ruipeng; Ren, Yi; Chen, Long; Payne, Marcia M.; Bhansali, Unnat Sampatraj; Smilgies, Detlef Matthias; Anthony, John Edward; Amassian, Aram

2013-01-01

We demonstrate a new way to investigate and control the solvent vapor annealing of solution-cast organic semiconductor thin films. Solvent vapor annealing of spin-cast films of 6,13-bis(triisopropylsilylethynyl) pentacene (TIPS-Pn) is investigated in situ using quartz crystal microbalance with dissipation (QCM-D) capability, allowing us to monitor both solvent mass uptake and changes in the mechanical rigidity of the film. Using time-resolved grazing incidence wide angle X-ray scattering (GIWAXS) and complementary static atomic force microscopy (AFM), we demonstrate that solvent vapor annealing in the molecular regime can cause significant performance improvements in organic thin film transistors (OTFTs), whereas allowing the solvent to percolate and form a liquid phase results in catastrophic reorganization and dewetting of the film, making the process counterproductive. Using these lessons we devise processing conditions which prevent percolation of the adsorbed solvent vapor molecules for extended periods, thus extending the benefits of solvent vapor annealing and improving carrier mobility by nearly two orders of magnitude. Ultimately, it is demonstrated that QCM-D is a very powerful sensor of the state of the adsorbed solvent as well as the thin film, thus making it suitable for process development as well as in-line process monitoring both in laboratory and in future manufacturing settings. © 2013 American Chemical Society.

Properties and selection criteria for adsorbents

International Nuclear Information System (INIS)

Wirth, H.

1976-01-01

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.) [de

Mixed-matrix membrane adsorbers for protein separation

NARCIS (Netherlands)

Avramescu, M.E.; Borneman, Z.; Wessling, M.

2003-01-01

The separation of two similarly sized proteins, bovine serum albumin (BSA) and bovine hemoglobin (Hb) was carried out using a new type of ion-exchange mixed-matrix adsorber membranes. The adsorber membranes were prepared by incorporation of various types of Lewatit ion-exchange resins into an

Evidence for the concentration induced extinction of gas sensitivity in amorphous and nanostructured Te thin films

International Nuclear Information System (INIS)

Tsiulyanu, D.; Mocreac, O.; Enachi, M.; Volodina, G.

2013-01-01

The extinction of sensitivity to nitrogen dioxide induced by high gas concentration have been observed in ultrathin tellurium films. The phenomenon becomes apparent in both continuous and nanostructured films shown by AFM, SEM and XRD analyses to be in amorphous state. Sensitivity of 30 nm thickness Te film decreases near linearly with concentration increase between 150 and 500 ppb of nitrogen dioxide. The results are explained in terms of formation of a nitrogen dioxide catalytic gate in which a molecule adsorbs (and desorbs) without reacting. (authors)

Properties of two-dimensional insulators: A DFT study of bimetallic oxide CrW{sub 2}O{sub 9} clusters adsorption on MgO ultrathin films

Energy Technology Data Exchange (ETDEWEB)

Zhu, Jia, E-mail: jia_zhu@jxnu.edu.cn [College of Chemistry and Chemical Engineering, Jiangxi Normal University, Nanchang, Jiangxi 330022 (China); Zhang, Hui; Zhao, Ling; Xiong, Wei [College of Chemistry and Chemical Engineering, Jiangxi Normal University, Nanchang, Jiangxi 330022 (China); Huang, Xin; Wang, Bin [Department of Chemistry, Fuzhou University, Fuzhou, Fujian, 350108 (China); Zhang, Yongfan, E-mail: zhangyf@fzu.edu.cn [Department of Chemistry, Fuzhou University, Fuzhou, Fujian, 350108 (China); State Key Laboratory of Photocatalysis on Energy and Environment, Fuzhou, Fujian, 350002 (China)

2016-08-30

Highlights: • Completely different properties of CrW{sub 2}O{sub 9} on films compared with that on surface. • The first example of CT by electron tunneling from film to bimetallic oxide cluster. • A progressive Lewis acid site, better catalytic activities for adsorbed CrW{sub 2}O{sub 9}. - Abstract: Periodic density functional theory calculations have been performed to study the electronic properties of bimetallic oxide CrW{sub 2}O{sub 9} clusters adsorbed on MgO/Ag(001) ultrathin films (<1 nm). Our results show that after deposition completely different structures, electronic properties and chemical reactivity of dispersed CrW{sub 2}O{sub 9} clusters on ultrathin films are observed compared with that on the thick MgO surface. On the thick MgO(001) surface, adsorbed CrW{sub 2}O{sub 9} clusters are distorted significantly and just a little electron transfer occurs from oxide surface to clusters, which originates from the formation of adsorption dative bonds at interface. Whereas on the MgO/Ag(001) ultrathin films, the resulting CrW{sub 2}O{sub 9} clusters keep the cyclic structures and the geometries are similar to that of gas-phase [CrW{sub 2}O{sub 9}]{sup −}. Interestingly, we predicted the occurrence of a net transfer of one electron by direct electron tunneling from the MgO/Ag(001) films to CrW{sub 2}O{sub 9} clusters through the thin MgO dielectric barrier. Furthermore, our work reveals a progressive Lewis acid site where spin density preferentially localizes around the Cr atom not the W atoms for CrW{sub 2}O{sub 9}/MgO/Ag(001) system, indicating a potentially good bimetallic oxide for better catalytic activities with respect to that of pure W{sub 3}O{sub 9} clusters. As a consequence, present results reveal that the adsorption of bimetallic oxide CrW{sub 2}O{sub 9} clusters on the MgO/Ag(001) ultrathin films provide a new perspective to tune and modify the properties and chemical reactivity of bimetallic oxide adsorbates as a function of the thickness

Thermodynamics of gas adsorption on solid adsorbents

International Nuclear Information System (INIS)

Budrugeac, P.

1979-01-01

Starting with several hypotheses about the adsorbtion system and the adsorption phenomenon, a thermodynamic treatment of gas adsorption on solid adsorbants is presented. The relationships for determination from isotherms and calorimetric data of thermodynamic functions are derived. The problem of the phase changes in adsorbed layer is discussed. (author)

Hydrolysis of mixed monomolecular films of triglyceride/lecithin by pancreatic lipase.

Science.gov (United States)

Pieroni, G; Verger, R

1979-10-25

The main purpose of this study was to describe the influence of lecithin upon lipolysis of mixed monomolecular films of trioctanoylglycerol/didodecanoylphosphatidycholine by pancreatic lipase in order to mimic some physiological situations. The quantity of enzyme adsorbed to the interface was simultaneously determined using 5-thio-2-nitro[14C]benzoyl lipase. Lipolytic activity was enhanced 3- to 4-fold in the presence of colipase, an effect which is attributed to increased enzyme turnover number. When a pure triglyceride film was progressively diluted with lecithin, the minimum specific activity of lipase exhibited a bell-shaped curve: a mixed film containing only 20% trioctanoylglycerol was hydrolyzed at the same rate as a monolayer of pure triglyceride.

Water adsorbate phases on ZnO and impact of vapor pressure on the equilibrium shape of nanoparticles

Science.gov (United States)

Kenmoe, Stephane; Biedermann, P. Ulrich

2018-02-01

ZnO nanoparticles are used as catalysts and have potential applications in gas-sensing and solar energy conversion. A fundamental understanding of the exposed crystal facets, their surface chemistry, and stability as a function of environmental conditions is essential for rational design and improvement of synthesis and properties. We study the stability of water adsorbate phases on the non-polar low-index (10 1 ¯ 0 ) and (11 2 ¯ 0 ) surfaces from low coverage to multilayers using ab initio thermodynamics. We show that phonon contributions and the entropies due to a 2D lattice gas at low coverage and multiple adsorbate configurations at higher coverage have an important impact on the stability range of water adsorbate phases in the (T,p) phase diagram. Based on this insight, we compute and analyze the possible growth mode of water films for pressures ranging from UHV via ambient conditions to high pressures and the impact of water adsorption on the equilibrium shape of nanoparticles in a humid environment. A 2D variant of the Wulff construction shows that the (10 1 ¯ 0 ) and (11 2 ¯ 0 ) surfaces coexist on 12-faceted prismatic ZnO nanoparticles in dry conditions, while in humid environment, the (10 1 ¯ 0 ) surface is selectively stabilized by water adsorption resulting in hexagonal prisms.

Adsorption isotherms, kinetics and column operations for the removal of hazardous dye, Tartrazine from aqueous solutions using waste materials-Bottom Ash and De-Oiled Soya, as adsorbents

International Nuclear Information System (INIS)

Mittal, Alok; Mittal, Jyoti; Kurup, Lisha

2006-01-01

Adsorbents, Bottom Ash (a power plant waste) and De-Oiled Soya (an agricultural waste) exhibit good efficacy to adsorb a highly toxic dye, Tartrazine. Through the batch technique equilibrium uptake of the dye is observed at different concentrations, pH of the solution, dosage of adsorbents and sieve size of adsorbents. Langmuir and Freundlich adsorption isotherms are successfully employed on both the adsorbents and on the basis of these models the thermodynamic parameters are evaluated. Kinetic investigations reveal that more than 50% adsorption of dye is achieved in about 1 h in both the cases, whereas, equilibrium establishment takes about 3-4 h. The linear plots obtained in rate constant and mass transfer studies further confirm the applicability of first order rate expression and mass transfer model, respectively. The kinetic data treated to identify rate controlling step of the ongoing adsorption processes indicate that for both the systems, particle diffusion process is predominant at higher concentrations, while film diffusion takes place at lower concentrations. The column studies reveal that about 96% saturation of both the columns is attained during their exhaustion, while about 88 and 84% of the dye material is recovered by eluting dilute NaOH solution through exhausted Bottom Ash and De-Oiled Soya columns, respectively

Adsorption isotherms, kinetics and column operations for the removal of hazardous dye, Tartrazine from aqueous solutions using waste materials-Bottom Ash and De-Oiled Soya, as adsorbents

Energy Technology Data Exchange (ETDEWEB)

Mittal, Alok [Department of Applied Chemistry, Maulana Azad National Institute of Technology, Bhopal 462 007 (India)]. E-mail: aljymittal@yahoo.co.in; Mittal, Jyoti [Department of Applied Chemistry, Maulana Azad National Institute of Technology, Bhopal 462 007 (India); Kurup, Lisha [Department of Applied Chemistry, Maulana Azad National Institute of Technology, Bhopal 462 007 (India)

2006-08-25

Adsorbents, Bottom Ash (a power plant waste) and De-Oiled Soya (an agricultural waste) exhibit good efficacy to adsorb a highly toxic dye, Tartrazine. Through the batch technique equilibrium uptake of the dye is observed at different concentrations, pH of the solution, dosage of adsorbents and sieve size of adsorbents. Langmuir and Freundlich adsorption isotherms are successfully employed on both the adsorbents and on the basis of these models the thermodynamic parameters are evaluated. Kinetic investigations reveal that more than 50% adsorption of dye is achieved in about 1 h in both the cases, whereas, equilibrium establishment takes about 3-4 h. The linear plots obtained in rate constant and mass transfer studies further confirm the applicability of first order rate expression and mass transfer model, respectively. The kinetic data treated to identify rate controlling step of the ongoing adsorption processes indicate that for both the systems, particle diffusion process is predominant at higher concentrations, while film diffusion takes place at lower concentrations. The column studies reveal that about 96% saturation of both the columns is attained during their exhaustion, while about 88 and 84% of the dye material is recovered by eluting dilute NaOH solution through exhausted Bottom Ash and De-Oiled Soya columns, respectively.

Adsorption isotherms, kinetics and column operations for the removal of hazardous dye, Tartrazine from aqueous solutions using waste materials--Bottom Ash and De-Oiled Soya, as adsorbents.

Science.gov (United States)

Mittal, Alok; Mittal, Jyoti; Kurup, Lisha

2006-08-25

Adsorbents, Bottom Ash (a power plant waste) and De-Oiled Soya (an agricultural waste) exhibit good efficacy to adsorb a highly toxic dye, Tartrazine. Through the batch technique equilibrium uptake of the dye is observed at different concentrations, pH of the solution, dosage of adsorbents and sieve size of adsorbents. Langmuir and Freundlich adsorption isotherms are successfully employed on both the adsorbents and on the basis of these models the thermodynamic parameters are evaluated. Kinetic investigations reveal that more than 50% adsorption of dye is achieved in about 1h in both the cases, whereas, equilibrium establishment takes about 3-4h. The linear plots obtained in rate constant and mass transfer studies further confirm the applicability of first order rate expression and mass transfer model, respectively. The kinetic data treated to identify rate controlling step of the ongoing adsorption processes indicate that for both the systems, particle diffusion process is predominant at higher concentrations, while film diffusion takes place at lower concentrations. The column studies reveal that about 96% saturation of both the columns is attained during their exhaustion, while about 88 and 84% of the dye material is recovered by eluting dilute NaOH solution through exhausted Bottom Ash and De-Oiled Soya columns, respectively.

Performance of adsorbent-embedded heat exchangers using binder-coating method

KAUST Repository

Li, Ang; Thu, Kyaw; Ismail, Azhar Bin; Shahzad, Muhammad Wakil; Ng, Kim Choon

2016-01-01

The performance of adsorption (AD) chillers or desalination cycles is dictated by the rates of heat and mass transfer of adsorbate in adsorbent-packed beds. Conventional granular-adsorbent, packed in fin-tube heat exchangers, suffered from poor heat

Photoemission spectroscopy of surfaces and adsorbates

International Nuclear Information System (INIS)

Chiang, T.C.; Kaindl, G.; Himpsel, F.J.; Eastman, D.E.

1982-01-01

Core level photoelectron spectroscopy is providing new information concerning the electronic properties of adsorbates and surfaces. Several examples will be discussed, including studies of adsorbed rare gas submonolayers and multilayers as well as clean metal surfaces. For rare gas multilayers adsorbed on metal surfaces, the photoelectrons and Auger electrons exhibit well-resolved increases in kinetic energy with decreasing distance between the excited atom and the substrate, allowing a direct labeling of the layers. These energy shifts are mainly due to the substrate screening effects, and can be described well by an image-charge model. For a Kr/Xe bilayer system prepared by first coating a Pd substrate with a monolayer of Kr and then overcoating with a layer of Xe, a thermally activated layer inversion process is observed when the temperature is raised, with Xe coming in direct contact with the substrate. For rare gas submonolayers adsorbed on the Al(111) surface, coverage-dependent core level shift and work function measurements provide information about the adatom spatial distributions, polarizabilities, and dipole moments for the ground and excited states. We have also studied the 2p core level shifts for a clean Al(001) surface relative to the bulk. The shifts have a large contribution from the initial-state effects

Selectivity of β-Sitosterol Imprinted Polymers as Adsorbent

Science.gov (United States)

Fauziah, St.; Hariani Soekamto, Nunuk; Taba, Paulina; Bachri Amran, Muh

2018-03-01

Molecularly Imprinted Polymers (MIPs) are smart materials that have been used as adsorbents in separation processes of compounds because they have a memorial effect to a certain compound. In this research, MIP synthesized was used as adsorbent for β-sitosterol. The objective of the research was to know the selectivity of MIP in adsorbing β-sitosterol. The concentrations of β-sitosterol after adsorption and desorption were analyzed by a UV-Vis spectrophotometer and the selectivity test was analyzed by HPLC. Result showed that the MIP had high adsorption ability ( qe ). The recovery of β-sitosterol from MIP for the adsorption-desorption process was 68.48%. The MIP was very selective to β-sitosterol compared to cholesterol because it can adsorb β-sitosterol as many as 100%, whereas the adsorption of cholesterol was only 30.27 %.

Gold recovery from low concentrations using nanoporous silica adsorbent

Science.gov (United States)

Aledresse, Adil

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

[Spectroscopic study on film formation mechanism and structure of composite silanes-V-Zr passive film].

Science.gov (United States)

Wang, Lei; Liu, Chang-sheng; Shi, Lei; An, Cheng-qiang

2015-02-01

A composite silanes-V-Zr passive film was overlayed on hot-dip galvanized steel. Attenuated total reflection Fourier transformed infrared spectroscopy (ATR-FTIR), X-ray photoelectron spectrometer (XPS) and radio frequency glow discharge optical emission spectrometry (rf-GD-OES) were used to characterize the molecular structure of the silanes-V-Zr passive film. The mechanism of film formation was discussed: The results show that the silane molecules are crosslinked as the main film former and inorganic inhibitor is even distributed in the film. The fitting peak of 100.7 eV in XPS single Si2p energy range spectra of the composite silanes-V-Zr passive film and the widening and strengthening of the Si--O infrared absorption peak at 1100 cm(-1) indicate that the silanes were adsorbed on the surface of zinc with chemical bond of Si--O--Zn, and the silane molecules were connected with each other by bond of Si--O--Si. Two characteristic absorption peaks of amide at 1650 and 1560 cm(-1) appear in the infrared spectroscopy of the composite silanes-V-Zr passive film, and a characteristic absorption peak of epoxy groups at 910 cm(-1) disappears in the infrared spectroscopy of the passive film. The results indicate that gamma-APT can be prepared through nucleophilic ring-opening of ethylene oxide in gamma-GPT molecule to form C--N covalent bonds. The rf-GD-OES results indicate that there is a oxygen enriched layer in 0.3 microm depth of the composite silanes-V-Zr passive film. Moreover, ZrF4, ZrO2 and some inorganic matter obtained by the reaction during the forming processof the composite silanes-V-Zr passive film are distributed evenly throughout the film. According to the film composition, the physical processes and chemical reactions during the film forming process were studied by using ATR-FTIR. Based on this, the film forming mechanism was proposed.

Krypton retention on solid adsorbents

International Nuclear Information System (INIS)

Monson, P.R. Jr.

1981-08-01

Over a dozen prospective adsorbents for krypton were studied and evaluated with respect to adsorption capacity and cost for dissolver off-gas streams from nuclear reprocessing plants. Results show that, at subambient temperature (-40 0 to -80 0 C), the commercially available hydrogen mordenite has sufficient adsorptive capacity to be the most cost-effective material studied. Silver mordenite has a higher capacity for krypton retention, but is 50 times more expensive than hydrogen mordenite. The results indicate that a solid adsorbent system is feasible and competitive with other developing systems whih utilize fluorocarbon absorption and cryogenic distillation

Browns Ferry charcoal adsorber incident

International Nuclear Information System (INIS)

Mays, G.T.

1979-01-01

The article reviews the temperature excursion in the charcoal adsorber beds of the Browns Ferry Unit 3 off-gas system that occurred on July 17, 1977. Significant temperature increases were experienced in the charcoal adsorber beds when charcoal fines were ignited by the ignition of a combustible mixture of hydrogen and oxygen in the off-gas system. The Browns Ferry off-gas system is described, and events leading up to and surrounding the incident are discussed. The follow-up investigation by Tennessee Valley Authority and General Electric Company personnel and their recommendations for system and operational modifications are summarized

Influence of helium-ion bombardment on the surface properties of pure and ammonia-adsorbed water thin films

International Nuclear Information System (INIS)

Kondo, M.; Shibata, T.; Kawanowa, H.; Gotoh, Y.; Souda, R.

2005-01-01

The influence of the ion bombardment on the surface properties of water-ice films has been investigated. The films are irradiated with 1.5 keV He + ions and analyzed sequentially on the basis of time-of-flight secondary-ion mass spectrometry (TOF-SIMS). In order to minimize any temperature-induced effects, the measurements were made at 15 K. The damage of the films, as estimated from the H/D exchange between NH 3 and the D 2 O ice and the intermixing of NH 3 with the H 2 18 O ice, is recognized at the fluence above 2 x 10 14 ions/cm 2 . The sputtering yield of the D 2 O ice is determined as 0.9 ± 0.2 molecules per incoming He + ion. The temperature-programmed TOF-SIMS analysis of the water-ice films has been completed within the fluence of 5.8 x 10 12 ions/cm 2 , so that no appreciable damage of the film should be induced during the measurement

Adsorption of β-galactosidase on silica and aluminosilicate adsorbents

Science.gov (United States)

Atyaksheva, L. F.; Dobryakova, I. V.; Pilipenko, O. S.

2015-03-01

It is shown that adsorption of β-galactosidase of Aspergillus oryzae fungi on mesoporous and biporous silica and aluminosilicate adsorbents and the rate of the process grow along with the diameter of the pores of the adsorbent. It is found that the shape of the adsorption isotherms changes as well, depending on the texture of the adsorbent: the Michaelis constant rises from 0.3 mM for the enzyme in solution to 0.4-0.5 mM for the enzyme on a surface in the hydrolysis of o-nitrophenyl-β-D-galactopyranoside. It is concluded that β-galactosidase displays its maximum activity on the surface of biporous adsorbents.

On dual nature of effect of adsorbed polymeric hydroxide films on rate of different electrode processes

International Nuclear Information System (INIS)

Zakharkina, P.S.; Korshunov, V.N.

1985-01-01

The effect of cation Er 3+ hydrolysis products on the electrochemical behaviour of Zn and Na amalgams is studied. The i, t-curves are presented which are moasUred from a film Hg-electrode in 1M LiCl- and 1MNaCl solUtions both with and without the 10 -3 MErCl 3 addition, along with the I, t-dependences obtained from a rotation disk Zn-electrode at E=-1.45 B against the background of 0.1 MLi 2 SO 4 with the 1.5x10 -3 M Er 2 (SO 4 ) 3 addition. Polymeric films of REE oxohydroxo compounds exhibit a distinct dualism in the effect on the rate of different electrode reactions; provided a proton donor is the depolarizator, the films being considered confirm their name of catalytically active matrices accelerating hydrogen evolution by a modified bridge mechanism variant. In case of metal charge-ionization process these films become inhibitors and the more effective, the more hydrated is the corresponding REE ion

Electrochemical Properties of Alkanethiol Monolayers Adsorbed on Nanoporous Au Surfaces

International Nuclear Information System (INIS)

Chu, Yeon Yi; Seo, Bora; Kim, Jong Won

2010-01-01

We investigated the electrochemical properties of alkanethiol monolayers adsorbed on NPG surfaces by cyclic voltammetry and electrochemical impedance spectroscopy, and the results are compared to those on flat Au surfaces. The reductive desorption of alkanethiols on NPG surfaces is observed in more negative potential regions than that on flat Au surfaces due the stronger S-Au interaction on NPG surfaces. While the electron transfer through alkanethiol monolayers on flat Au surfaces occurs via a tunneling process through the monolayer films, the redox species can permeate through the monolayers on NPG surfaces to transfer the electrons to the Au surfaces. The results presented here will help to elucidate the intrinsic electrochemical properties of alkanethiol monolayers adsorbed on curved Au surfaces, particularly on the surface of AuNPs. Self-assembled monolayers (SAMs) of thiolate molecules on Au surfaces have been the subject of intensive research for the last few decades due to their unique physical and chemical properties. The well-organized surface structures of thiolate SAMs with various end-group functionalities can be further utilized for many applications in biology and nanotechnology. In addition to the practical applications, SAMs of thiolate molecules on Au surfaces also provide unique opportunities to address fundamental issues in surface chemistry such as self-organized surface structures, electron transfer behaviors, and moleculesubstrate interactions. Although there have been numerous reports on the fundamental physical and chemical properties of thiolate SAMs on Au surfaces, most of them were investigated on flat Au surfaces, typically on well-defined Au(111) surfaces

Production of Flocculants, Adsorbents, and Dispersants from Lignin.

Science.gov (United States)

Chen, Jiachuan; Eraghi Kazzaz, Armin; AlipoorMazandarani, Niloofar; Hosseinpour Feizi, Zahra; Fatehi, Pedram

2018-04-10

Currently, lignin is mainly produced in pulping processes, but it is considered as an under-utilized chemical since it is being mainly used as a fuel source. Lignin contains many hydroxyl groups that can participate in chemical reactions to produce value-added products. Flocculants, adsorbents, and dispersants have a wide range of applications in industry, but they are mainly oil-based chemicals and expensive. This paper reviews the pathways to produce water soluble lignin-based flocculants, adsorbents, and dispersants. It provides information on the recent progress in the possible use of these lignin-based flocculants, adsorbents, and dispersants. It also critically discusses the advantages and disadvantages of various approaches to produce such products. The challenges present in the production of lignin-based flocculants, adsorbents, and dispersants and possible scenarios to overcome these challenges for commercial use of these products in industry are discussed.

Protein purification using magnetic adsorbent particles

DEFF Research Database (Denmark)

Franzreb, M; Siemann-Herzberg, M.; Hobley, Timothy John

2006-01-01

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...... 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...

Deuteriding of thin titanium films: the effect of carbon monoxide surface contamination

International Nuclear Information System (INIS)

Malinowski, M.W.

1976-02-01

The effect of adsorbed CO on the deuteriding of thin titanium films at room temperature was measured at D 2 pressures between 10 to 25 mtorr on films contaminated with CO exposures ranging between approximately 10 -8 torr-seconds (''clean'') to 10 -4 torr-seconds. In all measurements, for deuterium/titanium atom ratios greater than .2, the deuteriding appeared to be initally limited by the sticking of D 2 on the clean or contaminated titanium deuteride surface; the effective sticking coefficient on a clean titanium deuteride surface was approximately 3 x 10 -3 , while on a surface contaminated with 10 -4 torr-seconds of CO, the coefficient was reduced to approximately, 2 x 10 -4 . The pumping speeds of Ti films were dramatically different when the films were evaporated over TiD 2 . These changes were attributed to the presence of deuterium which diffused from the substrate film into the overlayer film

A nuclear standard high-efficiency adsorber for iodine

International Nuclear Information System (INIS)

Wang Jianmin; Qian Yinge

1988-08-01

The structure of a nuclear standard high-efficiency adsorber, adsorbent and its performance are introduced. The performance and structure were compared with the same kind product of other firms. The results show that the leakage rate is less than 0.005%

Thermotropic phase transition in an adsorbed melissic acid film at the n-hexane-water interface

Science.gov (United States)

Tikhonov, A. M.

2017-06-01

A reversible thermotropic phase transition in an adsorption melissic acid film at the interface between n-hexane and an aqueous solution of potassium hydroxide (pH ≈ 10) is investigated by X-ray reflectometry and diffuse scattering using synchrotron radiation. The experimental data indicate that the interface "freezing" transition is accompanied not only by the crystallization of the Gibbs monolayer but also by the formation of a planar smectic structure in the 300-Å-thick adsorption film; this structure is formed by 50-Å-thick layers.

Superhydrophilic SnO{sub 2} nanosheet-assembled film

Energy Technology Data Exchange (ETDEWEB)

Masuda, Yoshitake, E-mail: masuda-y@aist.go.jp; Kato, Kazumi

2013-10-01

SnO{sub 2} films were fabricated on fluorine-doped tin oxide (FTO) substrates in aqueous solutions. The films of about 800 nm in thickness grew in the solutions containing SnF{sub 2} of 25 mM at 90 °C for 24 h. They consisted of nanosheets of about 5–10 nm in thickness and about 100–1600 nm in plane size. The films had gradient structure of nanosheets. Smaller nanosheets formed dense structures in a bottom area, while larger nanosheets formed porous structures in a surface area of the films. The SnO{sub 2} films showed higher transparency than bare FTO substrates in a visible light region of 470 to 850 nm. Decrease of reflectance increased transparency. The SnO{sub 2} films had superhydrophilic surfaces of static contact angle below 1°. Nanosheet-assembled structures contributed high hydrophilicity. The surfaces were further modified with light irradiation. High speed camera observation showed that spread speed of water was improved with the irradiation. Removal of surface adsorbed organic molecules and increase in the number of hydroxyl groups brought superhydrophilicity and high spread speed. - Highlights: ► SnO{sub 2} nanosheet films were prepared from aqueous solutions. ► The antireflective films showed superhydrophilicity. ► Crystal growth mechanism of the gradient structures is discussed.

Noble gas separation with the use of inorganic adsorbents

International Nuclear Information System (INIS)

Pence, D.T.; Chou, C.C.; Christian, J.D.; Paplawsky, W.J.

1979-01-01

A noble gas separation process is proposed for application to airborne nuclear fuel reprocessing plant effluents. The process involves the use of inorganic adsorbents for the removal of contaminant gases and noble gas separation through selective adsorption. Water and carbon dioxide are removed with selected zeolites that do not appreciably adsorb the noble gases. Xenon is essentially quantitatively removed with a specially developed adsorbent using conventional adsorption-desorption techniques. Oxygen is removed to low ppM levels by the use of a rapid cycle adsorption technique on a special adsorbent leaving a krypton-nitrogen mixture. Krypton is separated from nitrogen with a special adsorbent operated at about -80 0 C. Because the separation process does not require high pressures and oxygen is readily removed to sufficiently limit ozone formation to insignificant levels, appreciable capital and operating cost savings with this process are possible compared with other proposed processes. In addition, the proposed process is safer to operate

Electrochemistry and biosensing reactivity of heme proteins adsorbed on the structure-tailored mesoporous Nb2O5 matrix

International Nuclear Information System (INIS)

Xu Xin; Tian Bozhi; Zhang Song; Kong Jilie; Zhao Dongyuan; Liu Baohong

2004-01-01

The highly ordered mesoporous niobium oxides fabricated by self-adjusted synthesis have been used as immobilization matrices of heme proteins including Cytochrome c (Cyt C) and horseradish peroxidase (HRP) for their large surface areas, narrow pore size distributions and good biocompatibility. The assembling process was investigated by cyclic voltammetry, amperometry and potential step chronoamperometry in details. Niobium oxide matrices with different structural features were templated with the surfactants and the selectivity of these hosts to specific protein characteristics was determined. It was observed that proteins could be readily assembled onto the mesoporous films with detectable retention of bioactivity. The Nb 2 O 5 matrix with a tailored pore size and counterpoised surface charge to that of hemes allowed for a maximum adsorption capacity of biomolecules. The adsorbed redox molecules exhibited direct electrochemical behavior and gave a pair of well-defined quasi-reversible cyclic voltammetric peaks, indicating that the mesoporous niobium oxide matrix could effectively promote the direct electron transfer between the protein redox site adsorbed and the electrode surface. The midpoint redox potentials of adsorbed Cyt-c and HRP were 14 and -122 mV versus SCE, respectively. Furthermore, the immobilized HRP onto Nb 2 O 5 derived electrode presented good bioactivity and thus was fabricated as an amperometric biosensor for the response of hydrogen peroxide in the range from 0.1 μM to 0.1 mM

Neutralization of Rubidium Adsorbate Electric Fields by Electron Attachment

Energy Technology Data Exchange (ETDEWEB)

Sedlacek, J. A. [Univ. of Oklahoma, Norman, OK (United States); Kim, E. [Univ. of Nevada, Las Vegas, NV (United States); Rittenhouse, S. T. [Western Washington Univ., Bellingham, WA (United States); US Naval Academy, Annapolis, MD (United States); Weck, Philippe F [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Sadeghpour, H. R. [Harvard-Smithsonian Center for Astrophysics, Cambridge, MA (United States); Shaffer, J. P. [Univ. of Oklahoma, Norman, OK (United States)

2015-10-01

We investigate the (0001) surface of single crystal quartz with a submonolayer of Rb adsorbates. Using Rydberg atom electromagnetically induced transparency, we investigate the electric elds resulting from Rb adsorbed on the quartz surface, and measure the activation energy of the Rb adsorbates. We show that the Rb induces a negative electron affnity (NEA) on the quartz surface. The NEA surface allows for low energy electrons to bind to the surface and cancel the electric eld from the Rb adsorbates. Our results have implications for integrating Rydberg atoms into hybrid quantum systems and the fundamental study of atom-surface interactions, as well as applications for electrons bound to a 2D surface.

Characterization of novel adsorbents for radiostrontium reduction in foods

International Nuclear Information System (INIS)

Puziy, A.M.; Bengtsson, G.B.; Hansen, H.S.

1999-01-01

Distribution coefficients, pH dependence, isotherms, kinetics and breakthrough curves of Sr binding have been measured on several types of adsorbents (carbons modified with titanium silicate, crystalline titanium silicate, mixed titanium-manganese oxide, and synthetic zeolites A4 and P) from different water solutions. It is concluded that acid-base properties of the adsorbent is very important for Sr binding. Titanium silicate based adsorbents had reduced chemical stability in an artificial food fluid below pH 2, the mixed titanium manganese oxide below pH 6, zeolite A4 below pH 5 and zeolite P below pH 7. Consideration is given to the feasibility of the adsorbents for food decontamination. (author)

Methyl iodide tests on used adsorbents

International Nuclear Information System (INIS)

Kovach, J.L.

1993-01-01

This paper discusses the history of events leading to the current problems in radioiodine test conditions. These radioiodine tests are performed in the adsorbent media from both safety and non-safety related Nuclear Air Treatment Systems (NATS). The main problem addressed is that currently there are still numerous plant technical specifications for NATS which reference outdated test protocols for the surveillance testing of the radioactive methyl iodide performance of the adsorbents. Recommendations for correcting the test condition problems are presented. 7 refs

Adsorption characteristics of benzene on biosolid adsorbent and commercial activated carbons.

Science.gov (United States)

Chiang, Hung-Lung; Lin, Kuo-Hsiung; Chen, Chih-Yu; Choa, Ching-Guan; Hwu, Ching-Shyung; Lai, Nina

2006-05-01

This study selected biosolids from a petrochemical waste-water treatment plant as the raw material. The sludge was immersed in 0.5-5 M of zinc chloride (ZnCl2) solutions and pyrolyzed at different temperatures and times. Results indicated that the 1-M ZnCl2-immersed biosolids pyrolyzed at 500 degrees C for 30 min could be reused and were optimal biosolid adsorbents for benzene adsorption. Pore volume distribution analysis indicated that the mesopore contributed more than the macropore and micropore in the biosolid adsorbent. The benzene adsorption capacity of the biosolid adsorbent was 65 and 55% of the G206 (granular-activated carbon) and BPL (coal-based activated carbon; Calgon, Carbon Corp.) activated carbons, respectively. Data from the adsorption and desorption cycles indicated that the benzene adsorption capacity of the biosolid adsorbent was insignificantly reduced compared with the first-run capacity of the adsorbent; therefore, the biosolid adsorbent could be reused as a commercial adsorbent, although its production cost is high.

Production of Flocculants, Adsorbents, and Dispersants from Lignin

Directory of Open Access Journals (Sweden)

Jiachuan Chen

2018-04-01

Full Text Available Currently, lignin is mainly produced in pulping processes, but it is considered as an under-utilized chemical since it is being mainly used as a fuel source. Lignin contains many hydroxyl groups that can participate in chemical reactions to produce value-added products. Flocculants, adsorbents, and dispersants have a wide range of applications in industry, but they are mainly oil-based chemicals and expensive. This paper reviews the pathways to produce water soluble lignin-based flocculants, adsorbents, and dispersants. It provides information on the recent progress in the possible use of these lignin-based flocculants, adsorbents, and dispersants. It also critically discusses the advantages and disadvantages of various approaches to produce such products. The challenges present in the production of lignin-based flocculants, adsorbents, and dispersants and possible scenarios to overcome these challenges for commercial use of these products in industry are discussed.

In situ polymerization process of polypyrrole ultrathin films

International Nuclear Information System (INIS)

Onoda, Mitsuyoshi; Tada, Kazuya; Shinkuma, Akira

2006-01-01

A novel thin film processing technique has been developed for the fabrication of ultrathin films of conducting polymers with molecular-level control over thickness and multilayer architecture. This new self-assembly process opens up vast possibilities in applications which require large area, ultrathin films of conducting polymers and more importantly in applications that can take advantage of the unique interactions achievable in the complex, supermolecular architectures of multilayer films. In in situ polymerized polypyrrole (PPy), the deposition process strongly depends on the nature of the substrate surface. That is, for a surface that is negatively charged, there is a linear correspondence between dipping time and the amount of PPy deposited on the substrate. However, in the case of a positively charged surface, there is an apparent rest period of approximately 10-20 min, during which no PPy is deposited. From optical absorption spectroscopy and photoelectron emission studies etc., it became clear that oligomers of pyrrole were adsorbed on the positively charged surface during the rest period, as a result the polymerization reaction of PPy could proceed

Black molecular adsorber coatings for spaceflight applications

Science.gov (United States)

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

2014-09-01

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.

Friction and diffusion dynamics of adsorbates at surfaces

NARCIS (Netherlands)

Fusco, C.

2005-01-01

A theoretical study of the motion of adsorbates (e. g. atoms, molecules or clusters) on solid surfaces is presented, with a focus on surface diffusion and atomic-scale friction. These two phenomena are inextricably linked, because when an atomic or molecular adsorbate diffuses, or is pulled, it

Synthesis and properties of porous zeolite aluminosilicate adsorbents

International Nuclear Information System (INIS)

Shilina, A.S.; Milinchuk, V.K.; Burukhin, S.B.; Gordienko, A.B.

2015-01-01

Environmentally safe non-energy-intensive methods of the synthesis have been developed and the properties of solid inorganic nanostructured zeolite-like adsorbents of a broad spectrum have been studied. The sorption capacities of the adsorbents with respect to various components of water pollution have been determined [ru

The development of an adsorbent for corrosion products in high-temperature water

International Nuclear Information System (INIS)

Kim, Yong Ik; Sung, Ki Woung; Kim, Kwang Rag; Kim, Yu Hwan; Koo, Jae Hyoo

1996-08-01

In order to use as adsorbent for removal of the soluble corrosion products, mainly Co 60 under PWR reactor coolant conditions (300 deg C, 160 kg/cm 2 ), stable ZrO 2 adsorbent was prepared using sol-gel process from zirconyl nitrate, AlO adsorbent was prepared by hydrolysis of aluminum isopropoxide, and titanium tetraisopropoxide, respectively. The prepared adsorbents were calcined at various temperature and analyzed by physical properties and the Co 2+ adsorption capacity. And it was shown that the Co 2+ adsorption capacity of the TiO 2 -Al 2 O 3 adsorbents were found to have larger than that of ZrO 2 and Al 2 O 3 adsorbents in high-temperature water. ZrO 2 , Al 2 O 3 and TiO 2 -Al 2 O 3 adsorbents were found to be suitable high-temperature adsorbents for the removal of dissolved corrosion products, mainly Co in PWR reactor coolant conditions. 15 tabs., 51 figs., 55 refs. (Author)

Creation of the technical adsorbent from local raw materials

International Nuclear Information System (INIS)

Isobaev, M.D.; Davlatnazarova, M.D.; Abdullaev, T.H.

2016-01-01

The results showed the possibility of obtaining effective adsorbents of walnut shell and the sunflower for environmental purposes, in particular for the purification of polluted waters from heavy metals. It has been shown, that 1 g of walnut shell adsorbent can adsorb on its surface ions of lead in amount of 47% by weight. The dependence of the adsorption activity of the semi-coke received from walnut shell from particle size and concentration of the solution. (author)

Simultaneous Adsorption and Photocatalytic Degradation of Malachite Green Using Electrospun P(3HB-TiO2 Nanocomposite Fibers and Films

Directory of Open Access Journals (Sweden)

Nanthini Sridewi

2011-01-01

Full Text Available This paper demonstrated the applicability of electrospun P(3HB film as a dye adsorbent agent. Malachite green (MG was used as the model dye in this study. Interestingly, the electrospun P(3HB film exhibited excellent dye adsorption capacity whereby 78% of dye was adsorbed from a 30 μM solution of MG. The film was further improvised by incorporating titanium dioxide photocatalysts to form a dual dye treatment system employing adsorption and photocatalytic degradation techniques. The resultant electrospun P(3HB-50 wt%   TiO2 was capable of completely decolorizing MG in 45 min under solar irradiation, which corresponded to 58.7%  COD removal. The fully decolorized MG solution also proved to be nontoxic against A. aegypti mosquito larvae. The reapplicability of this film was possible as it induced a decolorization rate of 98% or more at every usage for ten consequent usages. EDX analysis suggested that there were no significant changes in the concentration of titanium (Ti in the film before and after ten times of usage. The concentration of Ti in cast P(3HB-50 wt%  TiO2 film was found to decrease significantly during the repeated usage. The electrospun P(3HB-50 wt%  TiO2 film has high potency as an efficient and inexpensive yet simple method for the dye effluent decolorization, degradation, and detoxification.

Removal of VOCs from air stream with corrugated sheet as adsorbent

Directory of Open Access Journals (Sweden)

Rabia Arshad

2016-10-01

Full Text Available A large proportional of volatile organic compounds (VOCs are released into the environment from various industrial processes. The current study elucidates an application of a simple adsorption phenomenon for removal of three main types of VOCs, i.e., benzene, xylene and toluene, from an air stream. Two kinds of adsorbents namely acid digested adsorbent and activated carbon are prepared to assess the removal efficiency of each adsorbent in the indoor workplace environment. The results illustrate that the adsorbents prepared from corrugated sheets were remarkably effective for the removal of each pollutant type. Nevertheless, activated carbon showed high potential of adsorbing the targeted VOC compared to the acid digested adsorbent. The uptake by the adsorbents was in the following order: benzene > xylene > toluene. Moreover, maximum adsorption of benzene, toluene and xylene occurred at 20 °C and 1.5 cm/s for both adsorbents whereas minimum success was attained at 30 °C and 1.0 cm/s. However, adsorption pattern are found to be similar for each of the the three aromatic hydrocarbons. It is concluded that the corrugated sheets waste can be a considered as a successful and cost-effective solution towards effective removal of targeted pollutants in the air stream.

Ion plasma deposition of oxide films with graded-stoichiometry composition: Experiment and simulation

Science.gov (United States)

Volpyas, V. A.; Tumarkin, A. V.; Mikhailov, A. K.; Kozyrev, A. B.; Platonov, R. A.

2016-07-01

A method of ion plasma deposition is proposed for obtaining thin multicomponent films with continuously graded composition in depth of the film. The desired composition-depth profile is obtained by varying the working gas pressure during deposition in the presence of an additional adsorbing screen in the drift space between a sputtered target and substrate. Efficiency of the proposed method is confirmed by Monte Carlo simulation of the deposition of thin films of Ba x Sr1- x TiO3 (BSTO) solid solution. It is demonstrated that, during sputtering of a Ba0.3Sr0.7TiO3 target, the parameter of composition stoichiometry in the growing BSTO film varies in the interval of x = 0.3-0.65 when the gas pressure is changed within 2-60 Pa.

Adsorption characteristics of benzene on biosolid adsorbent and commercial activated carbons

Energy Technology Data Exchange (ETDEWEB)

Hung-Lung Chiang; Kuo-Hsiung Lin; Chih-Yu Chen; Ching-Guan Choa; Ching-Shyung Hwu; Nina Lai [China Medical University, Taichung (Taiwan). Department of Risk Management

2006-05-15

This study selected biosolids from a petrochemical wastewater treatment plant as the raw material. The sludge was immersed in 0.5-5 M of zinc chloride (ZnCl{sub 2}) solutions and pyrolyzed at different temperatures and times. Results indicated that the 1-M ZnCl{sub 2}-immersed biosolids pyrolyzed at 500{sup o}C for 30 min could be reused and were optimal biosolid adsorbents for benzene adsorption. Pore volume distribution analysis indicated that the mesopore contributed more than the macropore and micropore in the biosolid adsorbent. The benzene adsorption capacity of the biosolid adsorbent was 65 and 55% of the G206 (granular-activated carbon) and BPL (coal-based activated carbon; Calgon, Carbon Corp.) activated carbons, respectively. Data from the adsorption and desorption cycles indicated that the benzene adsorption capacity of the biosolid adsorbent was insignificantly reduced compared with the first-run capacity of the adsorbent; therefore, the biosolid adsorbent could be reused as a commercial adsorbent, although its production cost is high. 18 refs., 9 figs., 3 tabs.

Effect of aging and temperature on alternating current conductivity of tellurium thin films

Energy Technology Data Exchange (ETDEWEB)

Tsiulyanu, D. [Technical University, Department of Physics, bul. Dacia 41, MD-2060, Chisinau (Moldova, Republic of)], E-mail: tsiu@cni.md; Marian, T.; Tiuleanu, A. [Technical University, Department of Physics, bul. Dacia 41, MD-2060, Chisinau (Moldova, Republic of); Liess, H.-D.; Eisele, I. [University of the Bundeswehr Munich, Faculty of Electrical Engineering and Information Technology, Institute of Physics, D-85577 Neubiberg (Germany)

2009-02-27

The impedance spectra of tellurium films with interdigital platinum electrodes were investigated in air at temperatures between 10 and 50 deg. C . Cole-Cole analysis made it possible to assess time constants, resistance, and capacitance of the film at characteristic frequencies and the dependence of these parameters on aging and temperature. Aging under normal conditions over 12 months led to a relative increase of only {approx} 5% in film impedance at the characteristic frequency. However, aging noticeably influences the electrical resistance of the film at high (> 500 kHz) frequencies, and capacitance diminished after 12 months by more than 50% throughout the spectrum. Scanning electron microscopy confirmed that the effect of aging is due to structural changes in the film. Temperature does not influence the capacitance of the film but uncommonly influences its resistance, which reaches a maximum at around 20 deg. C . This is ascribed to desorption of oxygen previously adsorbed from the environment.

Effect of aging and temperature on alternating current conductivity of tellurium thin films

International Nuclear Information System (INIS)

Tsiulyanu, D.; Marian, T.; Tiuleanu, A.; Liess, H.-D.; Eisele, I.

2009-01-01

The impedance spectra of tellurium films with interdigital platinum electrodes were investigated in air at temperatures between 10 and 50 deg. C . Cole-Cole analysis made it possible to assess time constants, resistance, and capacitance of the film at characteristic frequencies and the dependence of these parameters on aging and temperature. Aging under normal conditions over 12 months led to a relative increase of only ∼ 5% in film impedance at the characteristic frequency. However, aging noticeably influences the electrical resistance of the film at high (> 500 kHz) frequencies, and capacitance diminished after 12 months by more than 50% throughout the spectrum. Scanning electron microscopy confirmed that the effect of aging is due to structural changes in the film. Temperature does not influence the capacitance of the film but uncommonly influences its resistance, which reaches a maximum at around 20 deg. C . This is ascribed to desorption of oxygen previously adsorbed from the environment

Layer-by-layer assembled highly absorbing hundred-layer films containing a phthalocyanine dye: Fabrication and photosensibilization by thermal treatment

International Nuclear Information System (INIS)

Sergeeva, Alena S.; Volkova, Elena K.; Bratashov, Daniil N.; Shishkin, Mikhail I.; Atkin, Vsevolod S.; Markin, Aleksey V.; Skaptsov, Aleksandr A.; Volodkin, Dmitry V.; Gorin, Dmitry A.

2015-01-01

Highly absorbing hundred-layer films based on poly(diallyldimethylammonium chloride) (PDADMAC) of various molecular weights and on sulfonated copper phthalocyanine (CuPcTs) were prepared using layer-by-layer assembly. The multilayer films grew linearly up to 54 bilayers, indicating that the same amount of CuPcTs was adsorbed at each deposition step. This amount, however, was dependent on the molecular weight of PDADMAC in the range 100-500 kDa: the higher the molecular weight, the more CuPcTs molecules were adsorbed. This can be explained by the larger surface charge number density specific to longer polymer chains. Domains of pure PDADMAC and of the PDADMAC/CuPcTs complex were formed in the films during the assembly. Uniform distribution of CuPcTs over the films could be achieved by thermal treatment, leading to an α → β phase transition in phthalocyanine at 300 °C. Annealing caused changes in the film absorbance spectra, resulting in a 30-nm red shift of the peak maxima and in a strong (up to 62%) decrease in optical density. Thermogravimetric analysis revealed thermodegradation of PDADMAC during annealing above 270 °C, giving rise to micrometer-sized cracks within the films, as evidenced by scanning electron microscopy. - Highlights: • The films exhibit the linear dependence of the adsorption on the bilayer number varied from 2 until 54. • Polyelectrolyte of the highest MW shows the maximal adsorption of copper phthalocyanine molecules. • Annealing of the films causes a red-shift of the maxima in the absorbance spectra. • Cracks and micropores emerged in the multilayer films during the annealing

Synchrotron x-ray-diffraction study of the structure and growth of Xe films adsorbed on the Ag(111) surface

International Nuclear Information System (INIS)

Dai, P.; Wu, Z.; Angot, T.; Wang, S.; Taub, H.; Ehrlich, S.N.

1999-01-01

Synchrotron x-ray scattering has been used to investigate the structure and growth of perhaps the simplest of all films: xenon physisorbed on the Ag(111) surface. High-resolution x-ray scans of the in-plane structure and lower-resolution scans (specular and nonspecular) of the out-of-plane order were performed. The Xe films were prepared under both quasiequilibrium and kinetic growth conditions, and have fewer structural defects than those investigated previously by others on graphite substrates. Under quasiequilibrium conditions, the bulk Xe-Xe spacing is reached at monolayer completion, and the monolayer and bilayer lattice constants at coexistence are inferred equal to within 0.005 Angstrom, consistent with theoretical calculations. The Xe/vacuum interface profile for a complete monolayer and bilayer grown at quasiequilibrium is found to be sharper than for kinetically grown films. At coverages above two layers, diffraction scans along the Xe(01l) rod for quasiequilibrated films are consistent with the presence of two domains having predominantly an ABC stacking sequence and rotated 60 degree with respect to each other about the surface normal. Annealing of these films alters neither the population of the two domains nor the fraction of ABA stacking faults. The thickest film grown under quasiequilibrium conditions exceeds 220 Angstrom (resolution limited). Under kinetic growth conditions, x-ray intensity oscillations at the Xe anti-Bragg position of the specular rod are observed as a function of time, indicating nearly layer-by-layer growth. Up to four complete oscillations corresponding to a film of eight layers have been observed before the intensity is damped out; the number of oscillations is found to depend on the substrate temperature, the growth rate, and the quality of the Ag(111) substrate. The specular reflectivity from kinetically grown films at nominal coverages of three and four layers has been analyzed using a Gaussian model which gives a film

Competitive Adsorption of a Two-Component Gas on a Deformable Adsorbent

OpenAIRE

Usenko, A. S.

2013-01-01

We investigate the competitive adsorption of a two-component gas on the surface of an adsorbent whose adsorption properties vary in adsorption due to the adsorbent deformation. The essential difference of adsorption isotherms for a deformable adsorbent both from the classical Langmuir adsorption isotherms of a two-component gas and from the adsorption isotherms of a one-component gas taking into account variations in adsorption properties of the adsorbent in adsorption is obtained. We establi...

Ionogenic adsorbents based on local raw materials for radiation protection

International Nuclear Information System (INIS)

Isobaev, M.D.; Davlatnazarova, M.; Turdialiev, M.Z.; Abdullayev, T.H.; Pulatov, E.H.

2012-01-01

The successful management of uranium wastes and creating the conditions for effective rehabilitation activities require special adsorbents capable of holding on the surface complexes, including radioactive elements. Currently tested and have shown promising synthetic adsorbents based pitted apricot fruits and other fruit plants. This report presents data for the establishment of ionic type available adsorbents based on Tajikistan coal. As the base for the creation of this type of adsorbent were taken the coal of the 'Ziddi' deposits. As follows from our data on the chemical composition, the studied coals contain more than 20% of the ash. According to the available literature theses ashes contains various minerals compositions that can form the adsorbent's active surface. Thus, the model for this type of activated carbon can serve as a mixture of zeolite, ion exchange resins and activated carbon itself.

Adsorbed radioactivity and radiographic imaging of surfaces of stainless steel and titanium

Science.gov (United States)

Jung, Haijo

1997-11-01

Type 304 stainless steel used for typical surface materials of spent fuel shipping casks and titanium were exposed in the spent fuel storage pool of a typical PWR power plant. Adsorption characteristics, effectiveness of decontamination by water cleaning and by electrocleaning, and swipe effectiveness on the metal surfaces were studied. A variety of environmental conditions had been manipulated to stimulate the potential 'weeping' phenomenon that often occurs with spent fuel shipping casks during transit. In a previous study, few heterogeneous effects of adsorbed contamination onto metal surfaces were observed. Radiographic images of cask surfaces were made in this study and showed clearly heterogeneous activity distributions. Acquired radiographic images were digitized and further analyzed with an image analysis computer package and compared to calibrated images by using standard sources. The measurements of activity distribution by using the radiographic image method were consistent with that using a HPGe detector. This radiographic image method was used to study the effects of electrocleaning for total and specified areas. The Modulation Transfer Function (MTF) of a film-screen system in contact with a radioactive metal surface was studied with neutron activated gold foils and showed more broad resolution properties than general diagnostic x-ray film-screen systems. Microstructure between normal areas and hot spots showed significant differences, and one hot spot appearing as a dot on the film image consisted of several small hot spots (about 10 μm in diameter). These hot spots were observed as structural defects of the metal surfaces.

Performance of adsorbent-embedded heat exchangers using binder-coating method

KAUST Repository

Li, Ang

2016-01-01

The performance of adsorption (AD) chillers or desalination cycles is dictated by the rates of heat and mass transfer of adsorbate in adsorbent-packed beds. Conventional granular-adsorbent, packed in fin-tube heat exchangers, suffered from poor heat transfer in heating (desorption) or cooling (adsorption) processes of the batch-operated cycles, with undesirable performance parameters such as higher footprint of plants, low coefficient of performance (COP) of AD cycles and higher capital cost of the machines. The motivation of present work is to mitigate the heat and mass "bottlenecks" of fin-tube heat exchangers by using a powdered-adsorbent cum binder coated onto the fin surfaces of exchangers. Suitable adsorbent-binder pairs have been identified for the silica gel adsorbent with pore surface areas up to 680 m2/g and pore diameters less than 6 nm. The parent silica gel remains largely unaffected despite being pulverized into fine particles of 100 μm, and yet maintaining its water uptake characteristics. The paper presents an experimental study on the selection and testing processes to achieve high efficacy of adsorbent-binder coated exchangers. The test results indicate 3.4-4.6 folds improvement in heat transfer rates over the conventional granular-packed method, resulting a faster rate of water uptake by 1.5-2 times on the suitable silica gel type. © 2015 Elsevier Ltd. All rights reserved.

Toward an effective adsorbent for polar pollutants: Formaldehyde adsorption by activated carbon

International Nuclear Information System (INIS)

Lee, Kyung Jin; Miyawaki, Jin; Shiratori, Nanako; Yoon, Seong-Ho; Jang, Jyongsik

2013-01-01

Highlights: • Activated carbon fiber with mild activation condition is useful as adsorbent for polar pollutants. • Diverse variations are investigated for developing an effective adsorbent. • Surface functional group is the most important factor for capacity as a adsorbent. • Surface functional groups on ACFs are investigated using micro-ATR FTIR. -- Abstract: Due to increasing concerns about environmental pollutants, the development of an effective adsorbent or sensitive sensor has been pursued in recent years. Diverse porous materials have been selected as promising candidates for detecting and removing harmful materials, but the most appropriate pore structure and surface functional groups, both important factors for effective adsorbency, have not yet been fully elucidated. In particular, there is limited information relating to the use of activated carbon materials for effective adsorbent of specific pollutants. Here, the pore structure and surface functionality of polyacrylonitrile-based activated carbon fibers were investigated to develop an efficient adsorbent for polar pollutants. The effect of pore structure and surface functional groups on removal capability was investigated. The activated carbons with higher nitrogen content show a great ability to absorb formaldehyde because of their increased affinity with polar pollutants. In particular, nitrogen functional groups that neighbor oxygen atoms play an important role in maximizing adsorption capability. However, because there is also a similar increase in water affinity in adsorbents with polar functional groups, there is a considerable decrease in adsorption ability under humid conditions because of preferential adsorption of water to adsorbents. Therefore, it can be concluded that pore structures, surface functional groups and the water affinity of any adsorbent should be considered together to develop an effective and practical adsorbent for polar pollutants. These studies can provide vital

The development of an adsorbent for corrosion products in high-temperature water

Energy Technology Data Exchange (ETDEWEB)

Kim, Yong Ik; Sung, Ki Woung; Kim, Kwang Rag; Kim, Yu Hwan; Koo, Jae Hyoo [Korea Atomic Energy Research Institute, Taejon (Korea, Republic of)

1996-08-01

In order to use as adsorbent for removal of the soluble corrosion products, mainly Co{sup 60} under PWR reactor coolant conditions (300 deg C, 160 kg/cm{sup 2}), stable ZrO{sub 2} adsorbent was prepared using sol-gel process from zirconyl nitrate, AlO adsorbent was prepared by hydrolysis of aluminum isopropoxide, and titanium tetraisopropoxide, respectively. The prepared adsorbents were calcined at various temperature and analyzed by physical properties and the Co{sup 2+} adsorption capacity. And it was shown that the Co{sup 2+} adsorption capacity of the TiO{sub 2}-Al{sub 2}O{sub 3} adsorbents were found to have larger than that of ZrO{sub 2} and Al{sub 2}O{sub 3} adsorbents in high-temperature water. ZrO{sub 2}, Al{sub 2}O{sub 3} and TiO{sub 2}-Al{sub 2}O{sub 3} adsorbents were found to be suitable high-temperature adsorbents for the removal of dissolved corrosion products, mainly Co in PWR reactor coolant conditions. 15 tabs., 51 figs., 55 refs. (Author).

Removal of arsenic from water using nano adsorbents and challenges: A review.

Science.gov (United States)

Lata, Sneh; Samadder, S R

2016-01-15

Many researchers have used nanoparticles as adsorbents to remove water pollutants including arsenic after modifying the properties of nanoparticles by improving reactivity, biocompatibility, stability, charge density, multi-functionalities, and dispersibility. For arsenic removal, nano adsorbents emerged as the potential alternatives to existing conventional technologies. The present study critically reviewed the past and current available information on the potential of nano adsorbents for arsenic removal from contaminated water and the challenges involved in that. The study discussed the separation and regeneration techniques of nano adsorbents and the performance thereof. The study evaluated the adsorption efficiency of the various nanoparticles based on size of nanoparticles, types of nano adsorbents, method of synthesis, separation and regeneration of the nano adsorbents. The study found that more studies are required on suitable holding materials for the nano adsorbents to improve the permeability and to make the technology applicable at the field condition. The study will help the readers to choose suitable nanomaterials and to take up further research required for arsenic removal using nano adsorbents. Copyright © 2015 Elsevier Ltd. All rights reserved.

Design and performance prediction of a new generation adsorption chiller using composite adsorbent

International Nuclear Information System (INIS)

Gong, L.X.; Wang, R.Z.; Xia, Z.Z.; Chen, C.J.

2011-01-01

Research highlights: → Composite adsorbent 'employing lithium chloride in silica gel' and water as working pair. → A new type adsorbent bed is used to accommodate the composite adsorbent. → A dynamic model of the adsorption chiller is built. → The coefficient of performance (COP) and the cooling capacity will be improved. -- Abstract: This paper presents a novel adsorption chiller using composite adsorbent 'employing lithium chloride in silica gel' as adsorbent and water as adsorbate. A new type adsorbent bed is used to accommodate the composite adsorbent. The mass recovery between two adsorbent beds usually results in the adsorbate unbalance. So a novel auto water makeup unite is used to solve the problem. A dynamic model of the adsorption chiller is built based on the adsorption isotherms to predict the performance. The simulation result shows that the coefficient of performance (COP) and the cooling capacity will increase by using this new composite adsorbent. When the temperatures of hot water inlet, cooling water inlet, and chilled water inlet are 363, 303 and 293 K, COP will be 0.43, and the cooling capacity will be 5.295 kW. Also operation strategy is optimized. Different temperatures of hot water inlet, cooling water inlet and chilling water inlet will result in different COP and cooling capacity.

Carbon/Attapulgite Composites as Recycled Palm Oil-Decoloring and Dye Adsorbents

Directory of Open Access Journals (Sweden)

Guangyan Tian

2018-01-01

Full Text Available Activated clay minerals have been widely used in the edible oil refining industry for decolorization of crude oil by adsorption, and so far many methods have been used to improve their decolorization efficiency. Herein, we successfully prepared a series of carbon/attapulgite (C/APT composite adsorbents by a one-step in-situ carbonization process with natural starch (St as the carbon source. It has been revealed that the adsorbent had better decolorization efficiency for crude palm oil than acid-activated APT. However, more than a million tons of decolorized waste is produced every year in the oil-refining industry, which was often treated as solid waste and has not yet been reutilized effectively. In order to explore a viable method to recycle and reuse the decolorant, the waste decolorant was further prepared into new C/APT adsorbents for the removal of dyes from wastewater, and then the dyes adsorbed on the adsorbent were used as the carbon sources to produce new C/APT adsorbents by a cyclic carbonization process. The results showed that the adsorbents prepared from the decolorized waste could remove more than 99.5% of the methylene blue (MB, methyl violet (MV, and malachite green (MG dyes from the simulated wastewater with the dye concentration of 200 mg/L, and the C/APT–Re adsorbent consecutively regenerated five times using the adsorbed dyes as a carbon source still exhibit good adsorption efficiency for dyes. As a whole, this process opens a new avenue to develop efficient decolorants of palm oil and achieves recyclable utilization of decolored waste.

Surface modification of porous nanocrystalline TiO2 films for dye-sensitized solar cell application by various gas plasmas

International Nuclear Information System (INIS)

Kim, Youngsoo; Yoon, Chang-Ho; Kim, Kang-Jin; Lee, Yeonhee

2007-01-01

Titanium dioxide (TiO 2 ) film for dye-sensitized solar cells (DSSCs) has surface defects such as oxygen vacancies created during the annealing process. The authors used a plasma treatment technique to reduce defects on TiO 2 surfaces. They investigated the influence of different gas plasma treatments of TiO 2 film on the photoelectric performance of DSSC. Short-circuit photocurrent density (J sc ), open-circuit photovoltage (V oc ), and the amount of adsorbed dye for DSSCs were measured. As a result, the solar-to-electricity conversion efficiencies of the O 2 - and N 2 -treated cells increased by 15%-20% compared to untreated cells. On the other hand, solar energy conversion efficiency of CF 4 -plasma treated cells decreased drastically. The increased amount of adsorbed dye on the TiO 2 film was measured by time-of-flight secondary ion mass spectrometry. TiO 2 surfaces modified by plasma treatment were characterized using analytical instruments such as x-ray photoelectron spectroscopy and near-edge x-ray absorption fine structure

An innovative zinc oxide-coated zeolite adsorbent for removal of humic acid

Energy Technology Data Exchange (ETDEWEB)

Wang, Lingling, E-mail: lasier_wang@hotmail.com [College of Chemical Engineering and Materials, Quanzhou Normal University, Quanzhou 362000, Fujian (China); Environmental Engineering and Science Program, 705 Engineering Research Center, University of Cincinnati, Cincinnati, OH 45221-0012 (United States); Han, Changseok [ORISE Post-doctoral Fellow, The U.S. Environmental Protection Agency, ORD, NRMRL, STD, CPB, 26 W. Martin Luther King Jr. Drive, Cincinnati, OH 45268 (United States); Nadagouda, Mallikarjuna N. [The U.S. Environmental Protection Agency, ORD, NRMRL, WSWRD, WQMB, 26 W. Martin Luther King Jr. Drive, Cincinnati, OH 45268 (United States); Dionysiou, Dionysios D., E-mail: dionysios.d.dionysiou@uc.edu [Environmental Engineering and Science Program, 705 Engineering Research Center, University of Cincinnati, Cincinnati, OH 45221-0012 (United States); Nireas-International Water Research Centre, School of Engineering, University of Cyprus, PO Box 20537, 1678, Nicosia (Cyprus)

2016-08-05

Highlights: • An innovative adsorbent was successfully synthesized to remove humic acid. • The adsorbent possessed high adsorption capacity for humic acid. • The adsorption capacity remarkably increased after an acid modification. • The adsorption capacity was proportional to the amount of ZnO coated on zeolite. • Electrostatic interactions are a major factor at the first stage of the process. - Abstract: Zinc oxide (ZnO)-coated zeolite adsorbents were developed by both nitric acid modification and Zn(NO{sub 3}){sub 2}·6H{sub 2}O functionalization of zeolite 4A. The developed adsorbents were used for the removal of humic acid (HA) from aqueous solutions. The synthesized materials were characterized by porosimetry analysis, scanning electron microscopy, X-Ray diffraction analysis, and high resolution transmission electron microscopy. The maximum adsorption capacity of the adsorbents at 21 ± 1 °C was about 60 mgC g{sup −1}. The results showed that the positive charge density of ZnO-coated zeolite adsorbents was proportional to the amount of ZnO coated on zeolite and thus, ZnO-coated zeolite adsorbents exhibited a greater affinity for negatively charged ions. Furthermore, the adsorption capacity of ZnO-coated zeolite adsorbents increased markedly after acid modification. Adsorption experiments demonstrated ZnO-coated zeolite adsorbents possessed high adsorption capacity to remove HA from aqueous solutions mainly due to strong electrostatic interactions between negative functional groups of HA and the positive charges of ZnO-coated zeolite adsorbents.

An innovative zinc oxide-coated zeolite adsorbent for removal of humic acid

International Nuclear Information System (INIS)

Wang, Lingling; Han, Changseok; Nadagouda, Mallikarjuna N.; Dionysiou, Dionysios D.

2016-01-01

Highlights: • An innovative adsorbent was successfully synthesized to remove humic acid. • The adsorbent possessed high adsorption capacity for humic acid. • The adsorption capacity remarkably increased after an acid modification. • The adsorption capacity was proportional to the amount of ZnO coated on zeolite. • Electrostatic interactions are a major factor at the first stage of the process. - Abstract: Zinc oxide (ZnO)-coated zeolite adsorbents were developed by both nitric acid modification and Zn(NO_3)_2·6H_2O functionalization of zeolite 4A. The developed adsorbents were used for the removal of humic acid (HA) from aqueous solutions. The synthesized materials were characterized by porosimetry analysis, scanning electron microscopy, X-Ray diffraction analysis, and high resolution transmission electron microscopy. The maximum adsorption capacity of the adsorbents at 21 ± 1 °C was about 60 mgC g"−"1. The results showed that the positive charge density of ZnO-coated zeolite adsorbents was proportional to the amount of ZnO coated on zeolite and thus, ZnO-coated zeolite adsorbents exhibited a greater affinity for negatively charged ions. Furthermore, the adsorption capacity of ZnO-coated zeolite adsorbents increased markedly after acid modification. Adsorption experiments demonstrated ZnO-coated zeolite adsorbents possessed high adsorption capacity to remove HA from aqueous solutions mainly due to strong electrostatic interactions between negative functional groups of HA and the positive charges of ZnO-coated zeolite adsorbents.

Equilibrium and heat of adsorption of diethyl phthalate on heterogeneous adsorbents

Energy Technology Data Exchange (ETDEWEB)

Zhang, W.M.; Xu, Z.W.; Pan, B.C.; Hong, C.H.; Jia, K.; Jiang, P.J.; Zhang, Q.J.; Pan, B.J. [Nanjing University, Nanjing (China)

2008-09-15

Removal of phthalate esters from water has been of considerable concern recently. In the present study, the adsorptive removal performance of diethyl phthalate (DEP) from water was investigated with the aminated polystyrene resin (NDA-101) and oxidized polystyrene resin (NDA-702). In addition, the commercial homogeneous polystyrene resin (XAD-4) and acrylic ester resin (Amberlite XAD-7) as well as coal-based granular activated carbon (AC-750) were chosen for comparison. The corresponding equilibrium isotherms are well described by the Freundlich equation and the adsorption capacities for DEP followed the order NDA-702 > NDA-101 > AC-750 > XAD-4 > XAD-7. Analysis of adsorption mechanisms suggested that these adsorbents spontaneously adsorb DEP molecules driven mainly by enthalpy change, and the adsorption process was derived by multiple adsorbent-adsorbate interactions such as hydrogen bonding, {pi}-{pi} stacking, and micropore filling. The information related to the adsorbent surface heterogeneity and the adsorbate-adsorbate interaction was obtained by Do's model. All the results indicate that heterogeneous resins NDA-702 and NDA-101 have excellent potential as an adsorption material for the removal of DEP from the contaminated water.

Adsorption Behavior of TBPS in the Process of Cu Electrodeposition on an Au Film.

Science.gov (United States)

Chen, Liang-Huei; Liu, Yung-Fang; Krug, Klaus; Lee, Yuh-Lang

2018-05-15

The adsorption behavior of an Cu electroplating additive, 3,3 thiobis-(1-propanesulfonic acid sodium salt) (TBPS) in a process of Cu deposition onto a single crystalline Au(111) surface is studied by an in-situ Surface-Enhanced Infrared Absorption Spectroscopy (SEIRAS). The SEIRAS spectra of the TBPS adlayer on a Cu film is investigated first and compared to that on an Au film. These results are utilized to evaluate the characteristics of TBPS adlayer on the electrode surface during the Cu deposition and stripping processes. The results show that the SEIRAS spectra of TBPS adsorbed on the Cu film resembles closely to that on the Au film, and the most pronounced peaks are symmetric S-O (ss-SO) and asymmetric S-O (as-SO) stretching modes. However, the as-SO band is sharper with a higher intensity on the Cu film. Since the ss-SO and as-SO peaks correspond to the molecular with upright and lie-down orientations, respectively, it implies that the TBPS molecules have higher ratio of lie-down orientation on the Cu film. In the Cu electrodeposition process, the cyclic voltammetry (CV) result shows that the presence of the TBPS in the HClO 4 solution can decrease the inhibition effect of HClO 4 to the Cu deposition. For the spectra measured at various potential during cathodic and anodic sweeping, an obvious change of the spectra occurs at ca. 0.6 V, the initiation of Cu underpotential deposition (Cu-UPD). For potentials higher and lower than 0.6 V, the spectra are similar, respectively, to those measured for the Au and Cu films. This result indicates that the TBPS molecules originally adsorbing on the Au film transfer to the surface of deposited Cu layer. This inference is also confirmed by the variation in wavenumber and peak intensity of ss-SO and as-SO peaks during the potential sweeping.

Characterization of interfaces between metals and organic thin films by electron and ion spectroscopies

Energy Technology Data Exchange (ETDEWEB)

Schmid, Martin

2012-01-18

In this thesis, interfaces between metals and organic thin films have been characterized with photoelectron and ion-scattering spectroscopies. Two different classes of metal/organic interfaces were examined in detail. First, interfaces which can be mainly characterized by relatively weak coordinative interactions between substrate and adsorbate. Second, interfaces which are mostly determined, or even created, by chemical reactions between different adsorbates or between adsorbates and substrate. Typical examples from the first class are metalated tetrapyrrole monolayers on Ag(111) and Au(111) single-crystal substrates. In this study, a focus was set to the interaction between iron and cobalt tetrapyrroles with Ag(111) or Au(111) substrates. A detailed examination of the corresponding photoelectron spectra revealed that the adsorbatesubstrate interaction is associated with a charge transfer from the metallic substrate to the Fe(II) or Co(II) ions within the tetrapyrrole units. The examination of cobalt(II) phthalocyanine monolayers further led to the conclusion that the magnetic moment, as present in unperturbed CoPc molecules, is efficiently quenched by the contact to the Ag(111) surface and the associated charge transfer. Similar investigations on Au(111) substrates gave evidence for possible adsorption site effects, further complicating the adsorbate/substrate interaction. Furthermore the formation of two-dimensional structures of poly(p-phenylene-terephthalamide) (PPTA, trademark Kevlar) on Ag(111) was closely examined. The Ag(111) surface does not only provide the geometrical boundary for the formation of the 2D covalent structures, but, moreover, actively participates in the reaction; after the adsorption of TPC molecules, a scission of the C-Cl bond, in particular at temperatures above 120 K, was evident. The resulting radical fragments appear stable and can act as reaction partners for the co-adsorbed PPD units. The chlorine atoms reside on the surface even

Lotus Dust Mitigation Coating and Molecular Adsorber Coating

Science.gov (United States)

O'Connor, Kenneth M.; Abraham, Nithin S.

2015-01-01

NASA Goddard Space Flight Center has developed two unique coating formulations that will keep surfaces clean and sanitary and contain contaminants.The Lotus Dust Mitigation Coating, modeled after the self-cleaning, water-repellant lotus leaf, disallows buildup of dust, dirt, water, and more on surfaces. This coating, has been successfully tested on painted, aluminum, glass, silica, and some composite surfaces, could aid in keeping medical assets clean.The Molecular Adsorber Coating is a zeolite-based, sprayable molecular adsorber coating, designed to prevent outgassing in materials in vacuums. The coating works well to adsorb volatiles and contaminates in manufacturing and processing, such as in pharmaceutical production. The addition of a biocide would also aid in controlling bacteria levels.

Studies of the surface structures of molecular crystals and of adsorbed molecular monolayers on the (111) crystal faces of platinum and silver by low-energy electron diffraction

International Nuclear Information System (INIS)

Firment, L.E.

1977-01-01

The structures of molecular crystal surfaces were investigated for the first time by the use of low-energy electron diffraction (LEED). The experimental results from a variety of molecular crystals were examined and compared as a first step towards understanding the properties of these surfaces on a microscopic level. The method of sample preparation employed, vapor deposition onto metal single-crystal substrates at low temperatures in ultrahigh vacuum, allowed concurrent study of the structures of adsorbed monolayers on metal surfaces and of the growth processes of molecular films on metal substrates. The systems investigated were ice, ammonia, naphthalene, benzene, the n-paraffins (C 3 to C 8 ), cyclohexane, trioxane, acetic acid, propionic acid, methanol, and methylamine adsorbed and condensed on both Pt(111) and Ag(111) surfaces. Electron-beam-induced damage of the molecular surfaces was observed after electron exposures of 10 -4 A sec cm -2 at 20 eV. Aromatic molecular crystal samples were more resistant to damage than samples of saturated molecules. The quality and orientation of the grown molecular crystal films were influenced by substrate preparation and growth conditions. Forty ordered monolayer structures were observed. 110 figures, 22 tables, 162 references

Complementary roles of benzylpiperazine and iodine 'vapor' in the strong enhancement of orange photoluminescence from CuI(1 1 1) thin film.

Science.gov (United States)

Rawal, Takat B; Turkowski, Volodymyr; Rahman, Talat S

2014-05-07

We have employed density functional theory, corrected by the on-site electron-electron repulsion energy U, to clarify the mechanism behind the enhanced orange photoluminescence (PL) of a CuI(1 1 1) thin film conjugated with a benzylpiperazine (BZP) molecule in the presence of an iodine 'vapor' atom. Our results demonstrated that the adsorbed molecule and the 'vapor' atom play complementary roles in producing the PL. The latter, in attaching to the film surface, creates a hole-trapping surface state located ~0.25 eV above the valence band-edge of the film, in good agreement with ~0.2 eV reported in experiments. Upon photo-excitation of the BZP/CuI(1 1 1) system in the presence of surface iodine 'vapor' atoms, excited electrons are transferred into the conduction band of CuI, and holes are trapped by the 'vapor' atoms. These holes, in turn, quickly relax into the HOMO state of the BZP molecule, owing to the fact that the molecule adsorbs on the film surface in the immediate vicinity of a 'vapor' atom. Relaxed holes subsequently recombine with excited electrons in the conduction band of the CuI film, thereby producing a luminescence peak at ~2.1 eV, in qualitative agreement with experimental findings.

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

Science.gov (United States)

Ćiçek, Ekrem; Dede, Bülent

2013-12-01

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

Black Sprayable Molecular Adsorber Coating

Data.gov (United States)

National Aeronautics and Space Administration — The main objective of this technology project is to develop, optimize, and flight qualify a black version of the molecular adsorber coating and a conductive version...

Mesoporous Silica: A Suitable Adsorbent for Amines

Directory of Open Access Journals (Sweden)

Abdollahzadeh-Ghom Sara

2009-01-01

Full Text Available Abstract Mesoporous silica with KIT-6 structure was investigated as a preconcentrating material in chromatographic systems for ammonia and trimethylamine. Its adsorption capacity was compared to that of existing commercial materials, showing its increased adsorption power. In addition, KIT-6 mesoporous silica efficiently adsorbs both gases, while none of the employed commercial adsorbents did. This means that KIT-6 Mesoporous silica may be a good choice for integrated chromatography/gas sensing micro-devices.

Methanol Adsorption and Reaction on Samaria Thin Films on Pt(111

Directory of Open Access Journals (Sweden)

Jin-Hao Jhang

2015-09-01

Full Text Available We investigated the adsorption and reaction of methanol on continuous and discontinuous films of samarium oxide (SmOx grown on Pt(111 in ultrahigh vacuum. The methanol decomposition was studied by temperature programmed desorption (TPD and infrared reflection absorption spectroscopy (IRRAS, while structural changes of the oxide surface were monitored by low-energy electron diffraction (LEED. Methanol dehydrogenates to adsorbed methoxy species on both the continuous and discontinuous SmOx films, eventually leading to the desorption of CO and H2 which desorbs at temperatures in the range 400–600 K. Small quantities of CO2 are also detected mainly on as-prepared Sm2O3 thin films, but the production of CO2 is limited during repeated TPD runs. The discontinuous film exhibits the highest reactivity compared to the continuous film and the Pt(111 substrate. The reactivity of methanol on reduced and reoxidized films was also investigated, revealing how SmOx structures influence the chemical behavior. Over repeated TPD experiments, a SmOx structural/chemical equilibrium condition is found which can be approached either from oxidized or reduced films. We also observed hydrogen absence in TPD which indicates that hydrogen is stored either in SmOx films or as OH groups on the SmOx surfaces.

Condition of granulating titanium-activated carbon composite adsorbent and its adsorption for uranium

International Nuclear Information System (INIS)

Miyai, Yoshitaka; Kitamura, Takao; Katoh, Shunsaku; Miyazaki, Hidetoshi

1979-01-01

The powdery titanium-activated carbon composite adsorbent was granulated, and the strength and uranium adsorptivity of the granulated adsorbent were studied in relation to its granulating condition. By use of polyvinylalcohol (PVA) with degree of polymerization above 2,000 as binder, the granular adsorbent with as much the same strength as commercial granular activated carbon was obtained. Addition of PVA did not affect the amount of adsorbed uranium in equilibrium, but decreased the adsorption rate. Effect of granule size between 2-5 mm on the uranium adsorption rate was that the uranium adsorption rate changed proportionally to surface area of assumed sphere. As a test for practical use, 5 times repetitions of adsorption and desorption were carried out on the same granular adsorbent. During this repetition the adsorbent containing formalized PVA revealed smaller weight loss than non-treated adsorbent. The amount of adsorbed uranium decreased with increasing repetition times, and reason of this was discussed. (author)

Adsorption of uranium on adsorbents produced from used tires

International Nuclear Information System (INIS)

Mahramanlioglu, M.

2003-01-01

Potential use of adsorbents produced from used tires for the removal of uranium from aqueous solutions is investigated. Two different adsorbents were used including char and activated carbon produced from used tires. The surface area was larger on activated carbon. Adsorption experiments were carried out as a function of time, adsorbent concentration, pH and initial concentration of uranium. The adsorption kinetics was found to follow the Lagergren equation. The rate constants of intraparticle diffusion and mass transfer coefficients were calculated. It was shown that the equilibrium data could be fitted by the Langmuir and Freundlich equations. The adsorption of uranium in the presence of different cations were also studied and the results were correlated with the ionic potential of the cations. It was demonstrated that the activated carbon produced from used tires can be considered as an adsorbent that has a commercial potential for uranium removal. (author)

Structural and X-Ray Photoelectron Spectroscopy Study of Al-Doped Zinc-Oxide Thin Films

Directory of Open Access Journals (Sweden)

Bong Ju Lee

2015-01-01

Full Text Available Al-doped zinc-oxide (AZO thin films were prepared by RF magnetron sputtering at different oxygen partial pressures and substrate temperatures. The charge-carrier concentrations in the films decreased from 1.69 × 1021 to 6.16 × 1017 cm−3 with increased gas flow rate from 7 to 21 sccm. The X-ray diffraction (XRD patterns show that the (002/(103 peak-intensity ratio decreased as the gas flow rate increased, which was related to the increase of AZO thin film disorder. X-ray photoelectron spectra (XPS of the O1s were decomposed into metal oxide component (peak A and the adsorbed molecular oxygen on thin films (peak B. The area ratio of XPS peaks (A/B was clearly related to the stoichiometry of AZO films; that is, the higher value of A/B showed the higher stoichiometric properties.

Unraveling the charge transfer/electron transport in mesoporous semiconductive TiO2 films by voltabsorptometry.

Science.gov (United States)

Renault, Christophe; Nicole, Lionel; Sanchez, Clément; Costentin, Cyrille; Balland, Véronique; Limoges, Benoît

2015-04-28

In this work, we demonstrate that chronoabsorptometry and more specifically cyclic voltabsorptometry are particularly well suited techniques for acquiring a comprehensive understanding of the dynamics of electron transfer/charge transport within a transparent mesoporous semiconductive metal oxide film loaded with a redox-active dye. This is illustrated with the quantitative analysis of the spectroelectrochemical responses of two distinct heme-based redox probes adsorbed in highly-ordered mesoporous TiO2 thin films (prepared from evaporation-induced self-assembly, EISA). On the basis of a finite linear diffusion-reaction model as well as the establishment of the analytical expressions governing the limiting cases, it was possible to quantitatively analyse, predict and interpret the unusual voltabsorptometric responses of the adsorbed redox species as a function of the potential applied to the semiconductive film (i.e., as a function of the transition from an insulating to a conductive state or vice versa). In particular, we were able to accurately determine the interfacial charge transfer rates between the adsorbed redox species and the porous semiconductor. Another important and unexpected finding, inferred from the voltabsorptograms, is an interfacial electron transfer process predominantly governed by the extended conduction band states of the EISA TiO2 film and not by the localized traps in the bandgap. This is a significant result that contrasts those previously observed for dye-sensitized solar cells formed of randomly sintered TiO2 nanoparticles, a behaviour that was ascribed to a particularly low density of localized surface states in EISA TiO2. The present methodology also provides a unique and straightforward access to an activation-driving force relationship according to the Marcus theory, thus opening new opportunities not only to investigate the driving-force effects on electron recombination dynamics in dye-sensitized solar cells but also to study the

Ice films follow structure zone model morphologies

International Nuclear Information System (INIS)

Cartwright, Julyan H.E.; Escribano, Bruno; Sainz-Diaz, C. Ignacio

2010-01-01

Ice films deposited at temperatures of 6-220 K and at low pressures in situ in a cryo-environmental scanning electron microscope show pronounced morphologies at the mesoscale consistent with the structure zone model of film growth. Water vapour was injected directly inside the chamber at ambient pressures ranging from 10 -4 Pa to 10 2 Pa. Several different substrates were used to exclude the influence of their morphology on the grown films. At the lowest temperatures the ice, which under these conditions is amorphous on the molecular scale, shows the mesoscale morphologies typical of the low-temperature zones of the structure zone model (SZM), including cauliflower, transition, spongelike and matchstick morphologies. Our experiments confirm that the SZM is independent of the chemical nature of the adsorbate, although the intermolecular interactions in water (hydrogen bonds) are different to those in ceramics or metals. At higher temperatures, on the other hand, where the ice is hexagonal crystalline on the molecular scale, it displays a complex palmlike morphology on the mesoscale.

Ice films follow structure zone model morphologies

Energy Technology Data Exchange (ETDEWEB)

Cartwright, Julyan H.E. [Instituto Andaluz de Ciencias de la Tierra, CSIC-Universidad de Granada, E-18071 Granada (Spain); Escribano, Bruno, E-mail: bruno.escribano.salazar@gmail.co [Instituto Andaluz de Ciencias de la Tierra, CSIC-Universidad de Granada, E-18071 Granada (Spain); Sainz-Diaz, C. Ignacio [Instituto Andaluz de Ciencias de la Tierra, CSIC-Universidad de Granada, E-18071 Granada (Spain)

2010-04-02

Ice films deposited at temperatures of 6-220 K and at low pressures in situ in a cryo-environmental scanning electron microscope show pronounced morphologies at the mesoscale consistent with the structure zone model of film growth. Water vapour was injected directly inside the chamber at ambient pressures ranging from 10{sup -4} Pa to 10{sup 2} Pa. Several different substrates were used to exclude the influence of their morphology on the grown films. At the lowest temperatures the ice, which under these conditions is amorphous on the molecular scale, shows the mesoscale morphologies typical of the low-temperature zones of the structure zone model (SZM), including cauliflower, transition, spongelike and matchstick morphologies. Our experiments confirm that the SZM is independent of the chemical nature of the adsorbate, although the intermolecular interactions in water (hydrogen bonds) are different to those in ceramics or metals. At higher temperatures, on the other hand, where the ice is hexagonal crystalline on the molecular scale, it displays a complex palmlike morphology on the mesoscale.

Polymeric ionic liquid based on magnetic materials fabricated through layer-by-layer assembly as adsorbents for extraction of pesticides.

Science.gov (United States)

He, Lijun; Cui, Wenhang; Wang, Yali; Zhao, Wenjie; Xiang, Guoqiang; Jiang, Xiuming; Mao, Pu; He, Juan; Zhang, Shusheng

2017-11-03

In this study, layer-by-layer assembly of polyelectrolyte multilayer films on magnetic silica provided a convenient and controllable way to prepare polymeric ionic liquid-based magnetic adsorbents. The resulting particles were characterized by Fourier transform infrared spectroscopy, X-ray diffraction, transmission electron microscopy, and magnetic measurements. The data showed that the magnetic particles had more homogeneous spherical shapes with higher saturation magnetization when compared to those obtained by free radical polymerization method. This facilitated the convenient collection of magnetic particles, with higher extraction repeatability. The extraction performance of the multilayer polymeric ionic liquid-based adsorbents was evaluated by magnetic solid-phase extraction of four pesticides including quinalphos, fenthion, phoxim, and chlorpropham. The data suggested that the extraction efficiency depended on the number of layers in the film. The parameters affecting the extraction efficiency were optimized, and good linearity ranging from 2 to 250μgL -1 was obtained with correlation coefficients of 0.9994-0.9998. Moreover, the proposed method presented low limit of detection (0.5μgL -1 , S/N=3) and limit of quantification (1.5μgL -1 , S/N=10), and good repeatability expressed by the relative standard deviation (2.0%-4.6%, n=5). The extraction recoveries of four pesticides were found to range from 58.9% to 85.8%. The reliability of the proposed method was demonstrated by analyzing environmental water samples, and the results revealed satisfactory spiked recovery, relative standard deviation, and selectivity. Copyright © 2017 Elsevier B.V. All rights reserved.

Heat transfer between adsorbate and laser-heated hot electrons

International Nuclear Information System (INIS)

Ueba, H; Persson, B N J

2008-01-01

Strong short laser pulses can give rise to a strong increase in the electronic temperature at metal surfaces. Energy transfer from the hot electrons to adsorbed molecules may result in adsorbate reactions, e.g. desorption or diffusion. We point out the limitations of an often used equation to describe the heat transfer process in terms of a friction coupling. We propose a simple theory for the energy transfer between the adsorbate and hot electrons using a newly introduced heat transfer coefficient, which depends on the adsorbate temperature. We calculate the transient adsorbate temperature and the reaction yield for a Morse potential as a function of the laser fluency. The results are compared to those obtained using a conventional heat transfer equation with temperature-independent friction. It is found that our equation of energy (heat) transfer gives a significantly lower adsorbate peak temperature, which results in a large modification of the reaction yield. We also consider the heat transfer between different vibrational modes excited by hot electrons. This mode coupling provides indirect heating of the vibrational temperature in addition to the direct heating by hot electrons. The formula of heat transfer through linear mode-mode coupling of two harmonic oscillators is applied to the recent time-resolved study of carbon monoxide and atomic oxygen hopping on an ultrafast laser-heated Pt(111) surface. It is found that the maximum temperature of the frustrated translation mode can reach high temperatures for hopping, even when direct friction coupling to the hot electrons is not strong enough

Chemical characterization of a marine conditioning film

Digital Repository Service at National Institute of Oceanography (India)

Garg, A.; Jain, A.; Bhosle, N

Biology 2, 228-235. Hung, C.C., Guo, L., Santschi, P.H., Quiroz, N.A., Haye, J.M., 2003. Distribution of carbohydrate species in the Gulf of Mexico. Marine Chemistry 18, 119-135. Little, B.J., Zsolnay, Z.A., 1985. Chemical fingerprinting of adsorbed...-110. Bhosle, N.B., Garg, A., Fernandes, L., Citon, P., 2005. Dynamics of amino acids in the conditioning film developed on glass panels immersed in surface seawaters of the Dona Paula Bay. Biofouling 21 (2), 99-107. Borch, N.H., Kirchmen, D.L., 1997...

Preparation of metal adsorbents from chitin/chitosan by radiation technology

International Nuclear Information System (INIS)

Nguyen Van Suc; Nguyen Quoc Hien; Ngo Quang Huy; Thai My Phe; Dao Van Hoang; Nguyen Van Hung

2004-01-01

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)

Investigations into Alternative Desorption Agents for Amidoxime-Based Polymeric Uranium Adsorbents

Energy Technology Data Exchange (ETDEWEB)

Gill, Gary A. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Kuo, Li-Jung [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Strivens, Jonathan E. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Wood, Jordana R. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Wai, Chien [LCW Supercritical Technologies, Inc., Seattle, WA (United States); Pan, Horng-Bin [Univ. of Idaho, Moscow, ID (United States)

2015-06-01

Amidoxime-based polymeric braid adsorbents that can extract uranium (U) from seawater are being developed to provide a sustainable supply of fuel for nuclear reactors. A critical step in the development of the technology is to develop elution procedures to selectively remove U from the adsorbents and to do so in a manner that allows the adsorbent material to be reused. This study investigates use of high concentrations of bicarbonate along with targeted chelating agents as an alternative means to the mild acid elution procedures currently in use for selectively eluting uranium from amidoxime-based polymeric adsorbents.

Single bank NOx adsorber for heavy duty diesel engines

NARCIS (Netherlands)

Genderen, M. van; Aken, M.G. van

2003-01-01

In a NOx adsorber programme the feasibility for applying this technology to heavy duty diesel engines was investigated. After modelling and simulations for realising best λ < 1 engine conditions a platform was build which was used to obtain good NOx adsorber regeneration settings in a number of

Comparative SPR study on the effect of nanomaterials on the biological activity of adsorbed proteins

International Nuclear Information System (INIS)

Mei, Q.; Chen, Y.; Hong, J.; Chen, H.; Ding, X.; Yin, Y.; Koh, K.; Lee, J.

2012-01-01

Bioactivity of proteins is evaluated to test the adverse effects of nanoparticles interjected into biological systems. Surface plasmon resonance (SPR) spectroscopy detects binding affinity that is normally related to biological activity. Utilizing SPR spectroscopy, a concise testing matrix is established by investigating the adsorption level of bovine serum albumin (BSA) and anti-BSA on the surface covered with 11-mercaptoundecanoic acid (MUA); magnetic nanoparticles (MNPs) and single-walled carbon nanotubes (SWCNTs), respectively. The immunoactivity of BSA on MNPs and SWCNT decreased by 18 % and 5 %, respectively, compared to that on the gold film modified with MUA. This indicates that MNPs cause a considerable loss of biological activity of adsorbed protein. This effect can be utilized for practical applications on detailed biophysical research and nanotoxicity studies. (author)

Enhanced vanillin production from ferulic acid using adsorbent resin.

Science.gov (United States)

Hua, Dongliang; Ma, Cuiqing; Song, Lifu; Lin, Shan; Zhang, Zhaobin; Deng, Zixin; Xu, Ping

2007-03-01

High vanillin productivity was achieved in the batch biotransformation of ferulic acid by Streptomyces sp. strain V-1. Due to the toxicity of vanillin and the product inhibition, fed-batch biotransformation with high concentration of ferulic acid was unsuccessful. To solve this problem and improve the vanillin yield, a biotransformation strategy using adsorbent resin was investigated. Several macroporous adsorbent resins were chosen to adsorb vanillin in situ during the bioconversion. Resin DM11 was found to be the best, which adsorbed the most vanillin and the least ferulic acid. When 8% resin DM11 (wet w/v) was added to the biotransformation system, 45 g l(-1) ferulic acid could be added continually and 19.2 g l(-1) vanillin was obtained within 55 h, which was the highest vanillin yield by bioconversion until now. This yield was remarkable for exceeding the crystallization concentration of vanillin and therefore had far-reaching consequence in its downstream processing.

Competitive adsorption of a two-component gas on a deformable adsorbent

International Nuclear Information System (INIS)

Usenko, A S

2014-01-01

We investigate the competitive adsorption of a two-component gas on the surface of an adsorbent whose adsorption properties vary due to the adsorbent deformation. The essential difference of adsorption isotherms for a deformable adsorbent both from the classical Langmuir adsorption isotherms of a two-component gas and from the adsorption isotherms of a one-component gas is obtained, taking into account variations in the adsorption properties of the adsorbent in adsorption. We establish bistability and tristability of the system caused by variations in adsorption properties of the adsorbent in competitive adsorption of gas particles on it. We derive conditions under which adsorption isotherms of a binary gas mixture have two stable asymptotes. It is shown that the specific features of the behavior of the system under study can be described in terms of a potential of the known explicit form. (paper)

Waste Material Adsorbents for Zinc Removal from Wastewater: A Comprehensive Review

Directory of Open Access Journals (Sweden)

Haider M. Zwain

2014-01-01

Full Text Available This review examines a variety of adsorbents and discusses mechanisms, modification methods, recovery and regeneration, and commercial applications. A summary of available researches has been composed by a wide range of potentially low-cost modified adsorbents including activated carbon, natural source adsorbents (clay, bentonite, zeolite, etc., biosorbents (black gram husk, sugar-beet pectin gels, citrus peels, banana and orange peels, carrot residues, cassava waste, algae, algal, marine green macroalgae, etc., and byproduct adsorbents (sawdust, lignin, rice husk, rice husk ash, coal fly ash, etc.. From the literature survey, different adsorbents were compared in terms of Zn2+ adsorption capacity; also Zn2+ adsorption capacity was compared with other metals adsorption. Thus, some of the highest adsorption capacities reported for Zn2+ are 168 mg/g powdered waste sludge, 128.8 mg/g dried marine green macroalgae, 73.2 mg/g lignin, 55.82 mg/g cassava waste, and 52.91 mg/g bentonite. Furthermore, modification of adsorbents can improve adsorption capacity. Regeneration cost is important, but if consumption of virgin adsorbent is reduced, then multiple economic, industrial, and environmental benefits can be gained. Finally, the main drawback of the already published Zn2+ adsorption researches is that their use is still in the laboratory stage mostly without scale-up, pilot studies, or commercialization.

Examination of uranium recovery technique from sea water using natural components for adsorbent

International Nuclear Information System (INIS)

Tanaka, Nobuyuki; Masaki, Hiroyuki; Shimizu, Takao; Tokiwai, Moriyasu

2010-01-01

In this study, we investigated the potency of natural components as adsorbent for uranium recovery from seawater. In addition, cost evaluation of uranium recovery from seawater using natural components for adsorbents was performed. Furthermore, new ideas on reservation system of adsorbents at sea area were proposed. Several poly-phenols were selected as adsorbent reagents, then they were adsorbed on the support such as cotton fiber by several methods as the followings; chemical syntheses, electrical beam irradiation, and traditional dyeing. As a result, the adsorbent made by traditional dyeing method using gallnut tannin as natural component, was showed high performance for uranium recovery from seawater on only the first. It was evaluated that traditional dyeing method had also advantage in the manufacturing cost, comparing with earlier method. Additionally, it was considered that reservation system of adsorbent at sea was able to be simplified compared with earlier system. Consequently, uranium recovery from sea water using natural components as adsorbent proposed in this study had a potency of practical use. (author)

Pumping experiment of water on B and LaB6 films with electron beam evaporator

International Nuclear Information System (INIS)

Mori, Takahiro; Hanaoka, Yutaka; Akaishi, Kenya; Kubota, Yusuke; Motojima, Osamu; Mushiaki, Motoi; Funato, Yasuyuki.

1992-10-01

Pumping characteristics of water vapor on boron and lanthanum hexaboride films formed with an electron beam evaporator have been investigated in high vacuum of a pressure region between 10 -4 and 10 -3 Pa. Measured initial maximum pumping speeds of water for fresh B and LaB 6 films on substrates with a deposition amount from 2.3 x 10 21 to 6.7 x 10 21 molecules·m -2 are 3.2 ∼ 4.9 m 3 ·s -1 ·m -2 , and maximum saturation amounts of adsorbed water on these films are 2.9 x 10 20 ∼ 1.3 x 10 21 H 2 O molecules·m -2 . (author)

Bare and protected sputtered-noble-metal films for surface-enhanced Raman spectroscopy

Science.gov (United States)

Talaga, David; Bonhommeau, Sébastien

2014-11-01

Sputtered silver and gold films with different surface morphologies have been prepared and coated with a benzenethiol self-assembled monolayer. Rough noble metal films showed strong Raman features assigned to adsorbed benzenethiol molecules upon irradiation over a wide energy range in the visible spectrum, which disclosed the occurrence of a significant surface-enhanced Raman scattering with maximal enhancement factors as high as 6 × 106. In addition, the adsorption of ethanethiol onto silver surfaces hinders their corrosion over days while preserving mostly intact enhancement properties of naked silver. This study may be applied to develop stable and efficient metalized probes for tip-enhanced Raman spectroscopy.

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...

Effect of filling surface-treated pyrolytic char on resistivity of rubber films

Directory of Open Access Journals (Sweden)

Pattraporn Yamkaya

2015-03-01

Full Text Available In this research, natural rubber (NR films filled with pyrolytic tire char, carbon black N234 and N330 were compared for their electrical resistivity. The filler loading was varied to be 5, 10, 15, 20 and 25% of dry rubber content. The effect of surfactant which is 2 %w/v sodium dodecyl sulfate (SDS was also investigated. In the experiments, it was necessary to disperse the pyrolytic char in ethyl alcohol while disperse carbon black (CB in ammonium hydroxide solution prior to mixing with the rubber latex and the filled NR film was prepared by casting the mixture on a plate. It was found that increasing the amount of pyrolytic char in the NR film could lower its resistivity. The surfactant, SDS, could help better dispersion of both CB and pyrolytic char, thereby decreasing the resistivity. In a separate experiment where hexane vapor was absorbed in NR film without surfactant, in the first 30 seconds, the rate of increasing resistivity of the CB-filled film was not seen as clearly as that of pyrolytic-char-filled film. For the films with surfactant, the slow increase in resistivity of the NR films filled with N330 and pyrolytic char during adsorbing hexane vapor was observed.

Combined ellipsometry and X-ray related techniques for studies of ultrathin organic nanocomposite films

Energy Technology Data Exchange (ETDEWEB)

Kraemer, Markus, E-mail: axo@standing-waves.d [Leibniz-Institut fuer Analytische Wissenschaften-ISAS-e.V., Bunsen-Kirchhoff-Str. 11, 44139 Dortmund (Germany); AXO DRESDEN GmbH, Siegfried-Raedel-Str. 31, 01809 Heidenau (Germany); Roodenko, Katy [Leibniz-Institut fuer Analytische Wissenschaften-ISAS-e.V.-Department Berlin, Albert-Einstein-Str. 9, 12489 Berlin (Germany); Laboratory for Surface and Nanostructure Modification, University of Texas at Dallas-NSERL, 800W. Campbell Rd., Richardson, TX 75080 (United States); Pollakowski, Beatrix [Physikalisch-Technische Bundesanstalt, Abbestr. 2-12, 10587 Berlin (Germany); Hinrichs, Karsten [Leibniz-Institut fuer Analytische Wissenschaften-ISAS-e.V.-Department Berlin, Albert-Einstein-Str. 9, 12489 Berlin (Germany); Rappich, Joerg [Helmholtz-Zentrum Berlin fuer Materialien und Energie GmbH, Abteilung Silizium-Photovoltaik, Kekulestr. 5, 12489 Berlin (Germany); Esser, Norbert [Leibniz-Institut fuer Analytische Wissenschaften-ISAS-e.V.-Department Berlin, Albert-Einstein-Str. 9, 12489 Berlin (Germany); Bohlen, Alex von; Hergenroeder, Roland [Leibniz-Institut fuer Analytische Wissenschaften-ISAS-e.V., Bunsen-Kirchhoff-Str. 11, 44139 Dortmund (Germany)

2010-07-30

Ultrathin nanocomposite films of nitrobenzene on silicon were analyzed by Infrared Spectroscopic Ellipsometry (IRSE), X-ray reflectivity (XRR) and X-ray standing waves (XSW) before and after evaporation of gold. Infrared Spectroscopic Ellipsometry measurements were performed for identification of adsorbates and for investigation of the molecular orientation. Results for film thickness were correlated with XRR measurements. Further, XSW measurements of elements incorporated in nitrobenzene (C, N, and O) were performed with soft X-rays. The combination of the different methods allowed to confirm a model for the electrochemically deposited nitrobenzene films before and after gold evaporation. The characterization by XRR and XSW scans using hard X-rays showed that gold had penetrated into the nitrobenzene film and thus changed density and optical properties of this layer significantly. A depth profile correlated to the electron density is deduced from the XRR measurements. This profile allows to localize-in vertical direction-gold islands within the composite film.

Comparative evaluation of selected starches as adsorbent for Thin ...

African Journals Online (AJOL)

The most commonly used is silica gel which is an inorganic adsorbent. Organic substances like cellulose, polyethylene are also used. All these are imported into Nigeria and are unhealthy for economic policies. Most commonly used adsorbent may not be easy to produce locally, but starch, which is a very common product, ...

A stochastic model of solid state thin film deposition: Application to chalcopyrite growth

Directory of Open Access Journals (Sweden)

Robert J. Lovelett

2016-04-01

Full Text Available Developing high fidelity quantitative models of solid state reaction systems can be challenging, especially in deposition systems where, in addition to the multiple competing processes occurring simultaneously, the solid interacts with its atmosphere. In this work, we develop a model for the growth of a thin solid film where species from the atmosphere adsorb, diffuse, and react with the film. The model is mesoscale and describes an entire film with thickness on the order of microns. Because it is stochastic, the model allows us to examine inhomogeneities and agglomerations that would be impossible to characterize with deterministic methods. We demonstrate the modeling approach with the example of chalcopyrite Cu(InGa(SeS2 thin film growth via precursor reaction, which is a common industrial method for fabricating thin film photovoltaic modules. The model is used to understand how and why through-film variation in the composition of Cu(InGa(SeS2 thin films arises and persists. We believe that the model will be valuable as an effective quantitative description of many other materials systems used in semiconductors, energy storage, and other fast-growing industries.

Application of low-cost adsorbents for dye removal--a review.

Science.gov (United States)

Gupta, V K; Suhas

2009-06-01

Dyes are an important class of pollutants, and can even be identified by the human eye. Disposal of dyes in precious water resources must be avoided, however, and for that various treatment technologies are in use. Among various methods adsorption occupies a prominent place in dye removal. The growing demand for efficient and low-cost treatment methods and the importance of adsorption has given rise to low-cost alternative adsorbents (LCAs). This review highlights and provides an overview of these LCAs comprising natural, industrial as well as synthetic materials/wastes and their application for dyes removal. In addition, various other methods used for dye removal from water and wastewater are also complied in brief. From a comprehensive literature review, it was found that some LCAs, in addition to having wide availability, have fast kinetics and appreciable adsorption capacities too. Advantages and disadvantages of adsorbents, favourable conditions for particular adsorbate-adsorbent systems, and adsorption capacities of various low-cost adsorbents and commercial activated carbons as available in the literature are presented. Conclusions have been drawn from the literature reviewed, and suggestions for future research are proposed.

Dynamics of CO 2 Adsorption on Amine Adsorbents. 2. Insights Into Adsorbent Design

KAUST Repository

Bollini, Praveen

2012-11-21

Packed bed breakthrough experiments are reported for commercial zeolite 13X and 3-aminopropyl-functionalized SBA-15 silica materials with three different amine loadings. Mass and heat transfer dynamics for all four materials are modeled successfully. Amine adsorbents with open pores are found to exhibit faster mass diffusion rates compared to zeolite 13X. When amine loading is increased by coupling aminopropyl groups, premature breakthrough combined with a long tail is observed. Contrary to conventional physisorbants, finite heat losses to the column wall do not explain the long breakthrough tail. A rate model that accounts for heterogeneity in diffusion was found to accurately capture the breakthrough shape of the high loading material. Batch uptake measurements support the hypothesis that slow diffusion through the polymer phase is what hampers adsorption kinetics in the high amine loading adsorbent. The results emphasize the importance of designing materials that are not overloaded with amine sites, as excessive amine loadings can lead to depressed adsorption kinetics and premature column breakthrough. © 2012 American Chemical Society.

Preparation and characterization of a novel adsorbent from Moringa oleifera leaf

Science.gov (United States)

Bello, Olugbenga Solomon; Adegoke, Kayode Adesina; Akinyunni, Opeyemi Omowumi

2017-06-01

A new and novel adsorbent was obtained by impregnation of Moringa oleifera leaf in H2SO4 and NaOH, respectively. Prepared adsorbents were characterized using elemental analysis, FT-IR, SEM, TGA and EDX analyses, respectively. The effects of operational parameters, such as pH, moisture content, ash content, porosity and iodine number on these adsorbents were investigated and compared with those of commercial activated carbon (CAC). EDX results of acid activated M. oleifera leaf have the highest percentage of carbon by weight (69.40 %) and (76.11 %) by atom, respectively. Proximate analysis showed that the fixed carbon content of acid activated M. oleifera leaf (69.14 ± 0.01) was the highest of all adsorbents studied. Conclusively, the present investigation shows that acid activated M. oleifera leaf is a good alternative adsorbent that could be used in lieu of CAC for recovery of dyes and heavy metal from aqueous solutions and other separation techniques.

Preparation and characterization of sponge film made from feathers.

Science.gov (United States)

Zhuang, Yuan; Wu, Xiaoqian; Cao, Zhangjun; Zhao, Xiaoxiang; Zhou, Meihua; Gao, Pin

2013-12-01

Feather wastes generated from poultry farms will pose a problem for disposal, but they are sustainable resources of keratin. Reduction is one of the commonly used methods to obtain soluble keratin from feather. However, the residues generated during feather reduction reaction were rarely investigated. In this study, the residues were transformed into a porous and flexible sponge film by freeze-drying without pretreatment or addition of cross-linking agents. Glycerol was used to alter the physical and chemical characteristics of the sponge film. The film was characterized with a fiber strong stretch instrument, a Fourier transform infrared spectrophotometer, scanning electron microscopy, an elemental analyzer, a differential scanning calorimeter and an automatic air permeability apparatus. Tensile strength and melting point of the sponge film with the optimum glycerol content were 6.2 MPa and 170°C respectively. Due to air permeability of 368 mm/s, the film can potentially be used in medicine, biology, textile, environmental technology, and so on. It is ecologically friendly and will produce additional benefits from the renewable materials. The film was utilized as adsorbents to remove Cr(VI) from aqueous solutions and as a filtering material for air pollution. Its maximum Cr(VI) uptake capacity was about 148.8 mg/g and the removal rate of PM10 was 98.3%. © 2013.

SAPO-34 coated adsorbent heat exchanger for adsorption chillers

International Nuclear Information System (INIS)

Freni, Angelo; Bonaccorsi, Lucio; Calabrese, Luigi; Caprì, Angela; Frazzica, Andrea; Sapienza, Alessio

2015-01-01

In this work, adsorbent coatings on aluminum surfaces were prepared by dip-coating method starting from a water suspension of SAPO-34 zeolite and a silane-based binder. Silane-zeolite coatings morphology and surface coverage grade were evaluated by scanning electron microscopy. Adhesive and mechanical properties were evaluated by peel, pull-off, impact and micro-hardness tests, confirming the good interaction between metal substrate, binder and zeolite. Adsorption equilibrium and kinetics of water vapour adsorption on the adsorbent coating were studied in the range T = 30–150 °C and pH 2 O = 11 mbar using a CAHN 2000 thermo-balance. It was found that, in the investigated conditions, the organic binder doesn't affect the water adsorption capacity and adsorption kinetics of the original SAPO-34 zeolite. Subsequently, the zeolite coating was applied on a finned flat-tubes aluminum heat exchanger realizing a full-scale AdHEx with an uniform adsorbent coating 0.1 mm thick and a metal/adsorbent mass ratio = 6. The cooling capacity of the realized coated AdHEx was measured by a lab-scale adsorption chiller under realistic operating conditions for air conditioning applications. The coated AdHEx produced up to 675 W/kg ads specific cooling power with a cycle time of 5 min. Adsorption stability of the coated adsorber subjected to 600 sorption cycles was successfully verified. - Highlights: • Adsorbent coatings on aluminum surfaces were prepared by dip-coating method. • Silane-zeolite coatings morphology, and mechanical properties were studied. • The zeolite coating was applied on a finned flat-tubes aluminum heat exchanger. • The coated AdHEx was tested in a lab scale adsorption chiller

An innovative zinc oxide-coated zeolite adsorbent for removal of humic acid

Science.gov (United States)

Zinc oxide (ZnO)-coated zeolite adsorbents were developed by both nitric acid modification and Zn(NO3)2•6H2O functionalization of zeolite. The developed adsorbents were used for the removal of humic acid (HA) from aqueous solutions. The adsorption capacity of the adsorbents at 21...

Electronic properties of adsorbates and clean surfaces of metals and semiconductors

International Nuclear Information System (INIS)

Lecante, J.

1980-01-01

This paper surveys recent progress in experimental studies on electronic properties of adsorbates and clean metal surfaces. Electron spectroscopy and particularly angle resolved photoelectron spectroscopy appears to be a very powerful tool to get informations on electronic levels of adsorbates or clean surfaces. Moreover this technique may also give informations about the atomic geometry of the surface. Experimental investigation about surface plasmons, surface states, core level shifts are presented for clean surfaces. As examples of adsorbate covered surfaces two typical cases are chosen: two dimensional band structure and oriented molecules. Finally the photoelectron diffraction may be used for surface structure determination either in the case of an adsorbate or a clean metal surface [fr

Biological adsorbent for water decontamination from uranium

Energy Technology Data Exchange (ETDEWEB)

Jilek, R [Vyzkumny Ustav Veterinarniho Lekarstvi, Brno-Medlanky (Czechoslovakia); Fuska, J; Nemec, P [Slovenska Vysoka Skola Technicka, Bratislava (Czechoslovakia). Chemickotechnologicka Fakulta

1978-01-01

A study was made into the capacity of native and heat-denaturated mycelium to adsorb uranium salts from solutions and into the effect of uranium on the growth of the microorganism biomass. The presence of uranium did not inhibit the growth of Penicillium and Aspergillus strains used at a concentration of up to 5x10/sup -4/ M/dm/sup 3/. Uranium added to a nutrient medium produced complexes with phosphorus ions which were adsorbed on the surface of growing hyphae, thus the removal of the mycelium also removed uranium. The results of the experiments with denaturated mycelium of the same strains suggested that uranium was also bound to the biomass with chemical bonds so that mycelium acted as a ''multifunction ion exchanger'' from which adsorbed uranium can be removed step by step by elution. A sorbent of a three-dimensional structure could be prepared from a dried native mycelium using reinforcing resins, which prevented leakage of the biomass. Uranium sorption by biosorbents is a function of the concentration of the cation sorbed and of the pH of the solution.

Biological adsorbent for water decontamination from uranium

International Nuclear Information System (INIS)

Jilek, R.; Fuska, J.; Nemec, P.

1978-01-01

A study was made into the capacity of native and heat-denaturated mycelium to adsorb uranium salts from solutions and into the effect of uranium on the growth of the microorganism biomass. The presence of uranium did not inhibit the growth of Penicillium and Aspergillus strains used at a concentration of up to 5x10 -4 M/dm 3 . Uranium added to a nutrient medium produced complexes with phosphorus ions which were adsorbed on the surface of growing hyphae, thus the removal of the mycelium also removed uranium. The results of the experiments with denaturated mycelium of the same strains suggested that uranium was also bound to the biomass with chemical bonds so that mycelium acted as a ''multifunction ion exchanger'' from which adsorbed uranium can be removed step by step by elution. A sorbent of a three-dimensional structure could be prepared from a dried native mycelium using reinforcing resins, which prevented leakage of the biomass. Uranium sorption by biosorbents is a function of the concentration of the cation sorbed and of the pH of the solution. (author)

Characterisation of lignite as an industrial adsorbent

Energy Technology Data Exchange (ETDEWEB)

Ying Qi; Andrew F.A. Hoadley; Alan L. Chaffee; Gil Garnier [Monash University, Clayton, Vic. (Australia). Department of Chemical Engineering

2011-04-15

An alternative use of the abundant and inexpensive lignite (also known as brown coal) as an industrial adsorbent has been characterised. The adsorptive properties of two Victorian lignite without any pre-treatment were investigated using the cationic methylene blue dye as a model compound in aqueous solutions. Two commercial activated carbon products were also studied for comparison. The adsorption equilibrium of the four adsorbents was better described by the Langmuir isotherm model than the Freundlich model. The adsorption capacities of the two untreated lignite adsorbents, Loy Yang and Yallourn, calculated using Langmuir isotherms were 286 and 370 mg/g, respectively, higher than a coconut shell-based activated carbon (167 mg/g), but lower than a coal-based activated carbon (435 mg/g). Surface area results suggested that larger micropores and mesopores were important for achieving good methylene blue adsorption by the activated carbons. However, FTIR and cation exchange capacity analyses revealed that, for the lignite, chemical interactions between lignite surface functional groups and methylene blue molecules occurred, thereby augmenting its adsorption capacity. 63 refs., 3 figs., 7 tabs.

Preparation and electrochemical properties of gold nanoparticles containing carbon nanotubes-polyelectrolyte multilayer thin films

International Nuclear Information System (INIS)

Yu Aimin; Zhang Xing; Zhang Haili; Han, Deyan; Knight, Allan R.

2011-01-01

Highlights: → Gold nanoparticles containing carbon nanotubes-polyelectrolyte multilayer thin films were prepared via layer-by-layer self-assembly technique. → The electron transfer behaviour of the hybrid thin films were investigated using an electrochemical probe. → The resulting thin films exhibited an electrocatalytic activity towards the oxidation of nitric oxide. - Abstract: Multi-walled carbon nanotubes (MWCNT)/polyelectrolyte (PE) hybrid thin films were fabricated by alternatively depositing negatively charged MWCNT and positively charged (diallyldimethylammonium chloride) (PDDA) via layer-by-layer (LbL) assembly technique. The stepwise growth of the multilayer films of MWCNT and PDDA was characterized by UV-vis spectroscopy. Scanning electron microscopy (SEM) images indicated that the MWCNT were uniformly embedded in the film to form a network and the coverage density of MWCNT increased with layer number. Au nanoparticles (NPs) could be further adsorbed onto the film to form PE/MWCNT/Au NPs composite films. The electron transfer behaviour of multilayer films with different compositions were studied by cyclic voltammetry using [Fe(CN) 6 ] 3-/4- as an electrochemical probe. The results indicated that the incorporation of MWCNT and Au NPs not only greatly improved the electronic conductivity of pure polyelectrolyte films, but also provided excellent electrocatalytic activity towards the oxidation of nitric oxide (NO).

Tungsten oxide nanowires grown on amorphous-like tungsten films

International Nuclear Information System (INIS)

Dellasega, D; Pezzoli, A; Russo, V; Passoni, M; Pietralunga, S M; Nasi, L; Conti, C; Vahid, M J; Tagliaferri, A

2015-01-01

Tungsten oxide nanowires have been synthesized by vacuum annealing in the range 500–710 °C from amorphous-like tungsten films, deposited on a Si(100) substrate by pulsed laser deposition (PLD) in the presence of a He background pressure. The oxygen required for the nanowires formation is already adsorbed in the W matrix before annealing, its amount depending on deposition parameters. Nanowire crystalline phase and stoichiometry depend on annealing temperature, ranging from W_1_8O_4_9-Magneli phase to monoclinic WO_3. Sufficiently long annealing induces the formation of micrometer-long nanowires, up to 3.6 μm with an aspect ratio up to 90. Oxide nanowire growth appears to be triggered by the crystallization of the underlying amorphous W film, promoting their synthesis at low temperatures. (paper)

Development of Silver-exchanged Adsorbents for the Removal of Fission Iodine from Alkaline Dissolution

International Nuclear Information System (INIS)

Kim, Taewoon; Lee, Seung-Kon; Lee, Suseung; Lee, Jun Sig

2015-01-01

Most of the iodine exists in the caustic dissolution as iodide form. KAERI is developing LEU-based fission 99 Mo production process which is connected to the new research reactor, which is being constructed in Kijang, Busan, Korea. In KAERI process, silver-exchanged adsorbent is used to adsorb iodide from the solution. Adsorbed iodide can be recovered and recycled for radiopharmaceuticals. In KAERI process, silver-exchanged adsorbent is used to adsorb iodide from the solution. Adsorbed iodide can be recovered and recycled for radiopharmaceuticals. Synthesis of silver-doped alumina is conducted in two ways. One is using the ascorbic acid as a reducing agent. However, this method is impossible to control

Analysis of Adsorbate-Adsorbate and Adsorbate-Adsorbent Interactions to Decode Isosteric Heats of Gas Adsorption.

Science.gov (United States)

Madani, S Hadi; Sedghi, Saeid; Biggs, Mark J; Pendleton, Phillip

2015-12-21

A qualitative interpretation is proposed to interpret isosteric heats of adsorption by considering contributions from three general classes of interaction energy: fluid-fluid heat, fluid-solid heat, and fluid-high-energy site (HES) heat. Multiple temperature adsorption isotherms are defined for nitrogen, T=(75, 77, 79) K, argon at T=(85, 87, 89) K, and for water and methanol at T=(278, 288, 298) K on a well-characterized polymer-based, activated carbon. Nitrogen and argon are subjected to isosteric heat analyses; their zero filling isosteric heats of adsorption are consistent with slit-pore, adsorption energy enhancement modelling. Water adsorbs entirely via specific interactions, offering decreasing isosteric heat at low pore filling followed by a constant heat slightly in excess of water condensation enthalpy, demonstrating the effects of micropores. Methanol offers both specific adsorption via the alcohol group and non-specific interactions via its methyl group; the isosteric heat increases at low pore filling, indicating the predominance of non-specific interactions. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Effect of γ-ray irradiation on adsorbents used in organic waste treatment

International Nuclear Information System (INIS)

Unsworth, T.J.; Krishma, R.; Pimblott, S.M.

2015-01-01

Radioactive organic liquids (ROLs) are waste that require specific treatment. The Arvia process, developed by Arvia Technology Ltd., combines adsorption of organic material with electrochemical oxidation. This work focuses on the effect of γ-rays on the performance of adsorbents used in the Arvia process. Adsorbents used in this experimental study were provided by Arvia Technology Ltd. Specifically, Nyex 1000, a flake like carbon-based adsorbent, and Nyex 2105, a carbon-based adsorbent with a granular morphology. The γ-ray irradiation experiments were carried out using a Co-60 irradiator. The impact of irradiation on the microstructure, the adsorption capacity and the leaching of the 2 adsorbents were studied. The results show that no significant changes were detected in terms of structure, adsorption capacity and leaching of ions. The results of this paper are promising for the use of Nyex 1000 and Nyex 2105 as adsorbents in electrochemical waste treatment processes which involve high levels of γ-rays. The article is followed by the slides of the presentation

Interactions of hydroxyapatite surfaces: conditioning films of human whole saliva.

Science.gov (United States)

Cárdenas, Marité; Valle-Delgado, Juan José; Hamit, Jildiz; Rutland, Mark W; Arnebrant, Thomas

2008-07-15

Hydroxyapatite is a very interesting material given that it is the main component in tooth enamel and because of its uses in bone implant applications. Therefore, not only the characterization of its surface is of high relevance but also designing reliable methods to study the interfacial properties of films adsorbed onto it. In this paper we apply the colloidal probe atomic force microscopy method to investigate the surface properties of commercially available hydroxyapatite surfaces (both microscopic particles and macroscopic discs) in terms of interfacial and frictional forces. In this way, we find that hydroxyapatite surfaces at physiological relevant conditions are slightly negatively charged. The surfaces were then exposed to human whole saliva, and the surface properties were re-evaluated. A thick film was formed that was very resistant to mechanical stress. The frictional measurements demonstrated that the film was indeed highly lubricating, supporting the argument that this system may prove to be a relevant model for evaluating dental and implant systems.

Synthesis of polymer/inorganic nanocomposite films using highly porous inorganic scaffolds.

Science.gov (United States)

Zhang, Huanjun; Popp, Matthias; Hartwig, Andreas; Mädler, Lutz

2012-04-07

Polymeric/inorganic nanocomposite films have been fabricated through a combination of flame-spray-pyrolysis (FSP) made inorganic scaffold and surface initiated polymerization of cyanoacrylate. The highly porous structure of pristine SnO(2) films allows the uptake of cyanoacrylate and the polymerization is surface initiated by the water adsorbed onto the SnO(2) surface. Scanning electron microscopy study reveals a nonlinear increase in the composite particle size and the film thickness with polymerization time. The structural change is rather homogeneous throughout the whole layer. The composite is formed mainly by an increase of the particle size and not by just filling the existing pores. High-resolution transmission electron microscopy imaging shows SnO(2) nanoparticles embedded in the polymeric matrix, constituting the nanocomposite material. Thermogravimetric analysis indicates that the porosity of the nanocomposite films decreases from 98% to 75%, resulting in a significant enhancement of the hardness of the films. DC conductivity measurements conducted in situ on the nanocomposite layer suggest a gradual increase in the layer resistance, pointing to a loss of connectivity between the SnO(2) primary particles as the polymerization proceeds. This journal is © The Royal Society of Chemistry 2012

Adsorbents for radioactive organic solvent wastes

International Nuclear Information System (INIS)

Ichinose, Shigeo; Kiribayashi, Takehiko.

1986-01-01

Purpose: To enable to settle radioactive solvents such as tributyl phosphate (TBP) and n-dodecane as they are without using hydrophobicizing agent such as quaternary ammonium salts. Constitution: The adsorbents are prepared by replacing interlaminer ions of swelling-type synthetic mica with alkaline earth metals or metal ions. For instance, synthetic micas introduced with Zr 4+ or Ca 2+ between the layers provide quite different functions from those of starting materials due to the properties of ions introduced between the layers. That is, they provide an intense affinity to organic phosphates such as TBP and transform into material showing a property of adsorbing and absorbing them. Particularly, the fixing nature to the phosphor content constituting TBP is significantly increased. (Horiuchi, T.)

Synthesis of adsorbent from Tamarix hispida and modified by lanthanum metal for fluoride ions removal from wastewater: Adsorbent characteristics and real wastewater treatment data

Directory of Open Access Journals (Sweden)

Nasim Habibi

2017-08-01

Full Text Available This data article describes a facile method for production of an adsorbent from Tamarix hispida wasted wood and modified by lanthanum metal for fluoride ions removal from wastewater. The main characteristics of the adsorbent consist of BET surface area, functional groups, and elemental analysis is presented. The data for attenuating the pollutants from a real wastewater treatment which was provided from a glass factory is also represented. More than 90% of fluoride content of the real wastewater was treated by the adsorbent. Generally, these data would be informative for extend research aim to industrial wastewater treatment and those who work in the wastewater treatment plants.

Scanning tunneling spectroscopy of Co adsorbates on superconducting Pb nanostructures

Energy Technology Data Exchange (ETDEWEB)

Decker, Regis; Caminale, Michael; Oka, Hirofumi; Stepniak, Agnieszka; Leon Vanegas, Augusto A.; Sander, Dirk; Kirschner, Juergen [Max-Planck-Institut fuer Mikrostrukturphysik, Weinberg 2, 06120 Halle (Germany)

2015-07-01

Superconductivity in low-dimensional structures has become an active research area. In order to understand the superconducting pairing, long-standing work has been devoted to the pair breaking effect, where magnetic impurities break Cooper pair singlets. We performed scanning tunneling spectroscopy at low temperature on Co adsorbates on superconducting Pb nanoislands. On the Co adsorbates, we observe spectral features in the superconductor's energy gap, which we attribute to magnetic impurity induced bound states, a hallmark of the pair breaking effect. We discuss the response of the superconducting islands to the presence of Co adsorbates.

Development of ultrafiltration and inorganic adsorbents: January--March 1977

International Nuclear Information System (INIS)

Koenst, J.W. Jr.

1977-01-01

Ultrafiltration media with and without the assistance of bone char filters were evaluated to determine their effectiveness in removing radionuclides from contaminated solutions. Precipitants, resin, adsorbents, and inorganic adsorbents were studied to determine their effectiveness in decontaminating solutions. A study of the effects of radiation on ultrafiltration media was initiated. An ultrafiltration media pilot plant was ordered and is being installed

Substrate effects on the characteristics of (In2O3)1-x (ZnO)x films

International Nuclear Information System (INIS)

Park, J. M.; Kim, J. J.; Kim, H. M.; Kim, J. H.; Ryu, S. W.; Park, S. H.; Ahn, J. S.

2006-01-01

The electrical and the optical properties of (In 2 O 3 ) 1-x (ZnO) x (IZO) films deposited by the rf magnetron sputtering on plastic substrates, such as polyethylene terephthalate (PET) and poly carbonate (PC), were investigated. The results are compared with those of IZO films deposited on a conventional coring glass (CG) substrate. The average transmittance of the IZO films deposited on plastic substrates is over 80 %, irrespective of the substrate, which is comparable to that of IZO films deposited on CG substrates. IZO films deposited on PC or PET substrates show larger resistivities than those deposited on CG substrates. This may be attributed to the fact that compositions, such as H 2 O or the organic solvent contained in the plastic substrates, are adsorbed into the IZO layer during sputtering. The surface resistance of the IZO films is nearly independent of the substrate and decreases with increasing deposition time. Compared to the IZO films deposited on PET substrates without hard coatings, those deposited on PET substrates with hard coatings show superior electrical stability for thermal environments.

Optical Properties of Sol-Gel Nb2O5 Films with Tunable Porosity for Sensing Applications

Directory of Open Access Journals (Sweden)

Rosen Georgiev

2015-01-01

Full Text Available Thin Nb2O5 films with tunable porosity are deposited by the sol-gel and evaporation induced self-assembly methods using organic template Pluronic PE6100 with different molar fractions with respect to NbCl5 used as a precursor for synthesis of Nb sol. Surface morphology and structure of the films are studied by Transmission Electron Microscopy and Selected Area Electron Diffraction. The optical characterization of the films is carried out through reflectance spectra measurements of the films deposited on silicon substrates and theoretical modeling in order to obtain refractive index, extinction coefficient, and thickness of the films. The overall porosity of the films and the amount of adsorbed acetone vapors in the pores are quantified by means of Bruggeman effective medium approximation using already determined optical constants. The sensing properties of the samples are studied by measuring both the reflectance spectra and room-temperature photoluminescence spectra prior to and after exposure to acetone vapors and liquid, respectively. The potential of using the studied mesoporous Nb2O5 films for chemooptical sensing is demonstrated and discussed.

Black Sprayable Molecular Adsorber Coating Project

Data.gov (United States)

National Aeronautics and Space Administration — The main objective of this technology project is to develop, optimize, and flight qualify a black version of the molecular adsorber coating and a conductive version...

Adsorption removal of hydrogen sulfide gas. IV. Characteristics of adsorbents for the adsorption removal of hydrogen sulfide gas

Energy Technology Data Exchange (ETDEWEB)

Boki, K

1974-10-25

The amount of hydrogen sulfide gas adsorbed was affected by the surface properties (surface pH, acid strength, acid amount, and basic amount), the surface structure (pore volume), and the surface form (scanning electron microscopic observation) of 32 tested adsorbents. In general, the amount adsorption increased in the following order, amount of H/sub 2/S adsorbed on the silicate adsorbents, on the active carbon adsorbents, and on the zeolite adsorbents. The amount of H/sub 2/S adsorbed on magnesium silicate and silica gel adsorbents was mainly affected by the surface structure, and the amount adsorbed on the aluminum silicate adsorbents was affected by the distinctions on the surface forms of the adsorbents. The amount of H/sub 2/S adsorbed on 10 kinds of active carbon was determined by the surface properties and the surface structures of the adsorbents. The amount adsorbed on 12 kinds of zeolites was determined by either the surface properties or by the surface structures of the adsorbents. The amount of H/sub 2/S adsorbed on the silicate, active carbon, and zeolite adsorbents interacted with the heat of adsorption, and among the same kinds of adsorbents, the amount adsorbed was linearly related to the heat of adsorption.

Retention of radium from thermal waters on sand filters and adsorbents

Energy Technology Data Exchange (ETDEWEB)

Elejalde, C. [Dpto. de Ingenieria Nuclear y Mecanica de Fluidos, Escuela Tecnica Superior de Ingenieria, Alameda de Urquijo s/n, 48013 Bilbao (Spain)]. E-mail: inpelsac@bi.ehu.es; Herranz, M. [Dpto. de Ingenieria Nuclear y Mecanica de Fluidos, Escuela Tecnica Superior de Ingenieria, Alameda de Urquijo s/n, 48013 Bilbao (Spain); Idoeta, R. [Dpto. de Ingenieria Nuclear y Mecanica de Fluidos, Escuela Tecnica Superior de Ingenieria, Alameda de Urquijo s/n, 48013 Bilbao (Spain); Legarda, F. [Dpto. de Ingenieria Nuclear y Mecanica de Fluidos, Escuela Tecnica Superior de Ingenieria, Alameda de Urquijo s/n, 48013 Bilbao (Spain); Romero, F. [Dpto. de Ingenieria Quimica y del Medio Ambiente, Escuela Tecnica Superior de Ingenieria, Alameda de Urquijo s/n, 48013 Bilbao (Spain); Baeza, A. [Dpto. de Fisica, Facultad de Veterinaria, Universidad de Extremadura, Avda. Universidad s/n, 10071 Caceres (Spain)

2007-06-18

This study was focussed on laboratory experiences of retention of radium from one thermal water on sand filters and adsorbents, trying to find an easy method for the elimination in drinkable waters polluted with this natural radio-nuclide. A thermal water from Cantabria (Spain) was selected for this work. Retention experiences were made with columns of 35 mm of diameter containing 15 cm layers of washed river sand or 4 cm layers of zeolite A3, passing known volumes of thermal water at flows between 4 and 40 ml/min with control of the retained radium by determining the amount in the water after the treatment. The statistical analysis of data suggests that retention depends on the flow and the volume passed through the columns. As additional adsorbents were used kaolin and a clay rich in illite. Jar-test experiences were made agitating known weights of adsorbents with the selected thermal water, with addition of flocculants and determination of radium in filtrated water after the treatment. Data suggest that retention is related to the weight of adsorbent used, but important quantities of radium seem remain in solution for higher amounts of adsorbents, according to the statistical treatment of data. The elution of retained radium from columns or adsorbents, previously used in experiences, should be the aim of a future research.

Retention of radium from thermal waters on sand filters and adsorbents

International Nuclear Information System (INIS)

Elejalde, C.; Herranz, M.; Idoeta, R.; Legarda, F.; Romero, F.; Baeza, A.

2007-01-01

This study was focussed on laboratory experiences of retention of radium from one thermal water on sand filters and adsorbents, trying to find an easy method for the elimination in drinkable waters polluted with this natural radio-nuclide. A thermal water from Cantabria (Spain) was selected for this work. Retention experiences were made with columns of 35 mm of diameter containing 15 cm layers of washed river sand or 4 cm layers of zeolite A3, passing known volumes of thermal water at flows between 4 and 40 ml/min with control of the retained radium by determining the amount in the water after the treatment. The statistical analysis of data suggests that retention depends on the flow and the volume passed through the columns. As additional adsorbents were used kaolin and a clay rich in illite. Jar-test experiences were made agitating known weights of adsorbents with the selected thermal water, with addition of flocculants and determination of radium in filtrated water after the treatment. Data suggest that retention is related to the weight of adsorbent used, but important quantities of radium seem remain in solution for higher amounts of adsorbents, according to the statistical treatment of data. The elution of retained radium from columns or adsorbents, previously used in experiences, should be the aim of a future research

Electronic structure of benzene adsorbed on Ni and Cu surfaces

Energy Technology Data Exchange (ETDEWEB)

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

1997-04-01

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.

TESTING OF CARBONACEOUS ADSORBENTS FOR REMOVAL OF POLLUTANTS FROM WATER

Directory of Open Access Journals (Sweden)

RAISA NASTAS

2012-03-01

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.

Foam-based adsorbents having high adsorption capacities for recovering dissolved metals and methods thereof

Science.gov (United States)

Janke, Christopher J.; Dai, Sheng; Oyola, Yatsandra

2015-06-02

Foam-based adsorbents and a related method of manufacture are provided. The foam-based adsorbents include polymer foam with grafted side chains and an increased surface area per unit weight to increase the adsorption of dissolved metals, for example uranium, from aqueous solutions. A method for forming the foam-based adsorbents includes irradiating polymer foam, grafting with polymerizable reactive monomers, reacting with hydroxylamine, and conditioning with an alkaline solution. Foam-based adsorbents formed according to the present method demonstrated a significantly improved uranium adsorption capacity per unit weight over existing adsorbents.

Experimental study on the basic characteristics of a novel silica-based CMPO adsorbent

International Nuclear Information System (INIS)

Wei, Yuezhou; Arai, Tsuyoshi; Zhang, Anyun; Hoshi, Harutaka; Koma, Yoshikazu; Watanabe, Masayuki

2002-01-01

In order to establish the extraction chromatography process for recovery of minor actinides from HLLW with a novel silica-based CMPO (octyl(phenyl)-N, N-diisobutylcarbamoylmethylphosphine oxide) adsorbent, some basic characteristics, such as dissolving behavior of CMPO from the adsorbent, thermal decomposition of the adsorbent and treatment method of organic wastes, were examined. It was found that the leakage of CMPO from the adsorbent in contact with an aqueous solution is the result of the solubility of CMPO in the solution. About 40-50 ppm of CMPO constantly leaked into the effluent from the adsorbent packed column using 0.01 M (M=mol/dm 3 ) HNO 3 as a mobile phase. The leakage of CMPO from the adsorbent could be effectively depressed with the utilization of the aqueous solution saturated by CMPO. TG-DTA thermal analysis results indicate that CMPO in the adsorbent decomposed at 20degC and the SDB-polymer at 290degC. The impregnated CMPO could be completely dissolved out from the support with acetone. Furthermore, the organic wastes such as CMPO, oxalic acid and DTPA those come from the elution procedure could be effectively decomposed with the Fenton reagent. (author)

Investigation of carbon nanotube-containing film on silicon substrates and its tribological behavior

Energy Technology Data Exchange (ETDEWEB)

Sun, Zhiyong [School of Mechanical Engineering, Shanghai Jiao Tong University, Shanghai 200240 (China); Cheng, Xianhua, E-mail: xhcheng@sjtu.edu.cn [School of Mechanical Engineering, Shanghai Jiao Tong University, Shanghai 200240 (China); State Key Laboratory of Solid Lubrication, Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences, Lanzhou 730000 (China)

2015-11-15

Highlights: • CNT-containing film was self-assembled on silicon substrates. • CNTs are strongly bonded with the substrates by chemical combination between La and oxygen-containing functional groups. • CNT-containing film has excellent friction reduction, load-carrying capacity and anti-wear ability. - Abstract: Carbon nanotubes (CNTs) were functionalized with Lanthanum (La) modifier and appropriate acid-treatment methods. CNT-containing film was deposited on silicon substrates via a self-assembly process. The formation and microstructure of La treated CNTs and CNT-containing film were characterized by high-resolution transmission electron microscopy (HRTEM), scanning electron microscopy (SEM), X-ray photoelectron spectrometry (XPS) and water contact angle (WCA). Its tribological properties were evaluated with a UMT-2MT reciprocating friction tester. The results show that CNTs were adsorbed on silicon substrates by means of chemically bonding between La and oxygen-containing functional groups. The friction coefficient of the silicon substrates is reduced from 0.87 to 0.12 after the deposition of CNT-containing film on its surface. CNT-containing film shows excellent antiwear, friction reducing ability and load-carrying capacity due to excellent mechanical and self-lubrication properties of CNTs.

Green Adsorbents for Wastewaters: A Critical Review

Directory of Open Access Journals (Sweden)

George Z. Kyzas

2014-01-01

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.

Green Adsorbents for Wastewaters: A Critical Review

Science.gov (United States)

Kyzas, George Z.; Kostoglou, Margaritis

2014-01-01

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. PMID:28788460

Oil palm biomass-based adsorbents for the removal of water pollutants--a review.

Science.gov (United States)

Ahmad, Tanweer; Rafatullah, Mohd; Ghazali, Arniza; Sulaiman, Othman; Hashim, Rokiah

2011-07-01

This article presents a review on the role of oil palm biomass (trunks, fronds, leaves, empty fruit bunches, shells, etc.) as adsorbents in the removal of water pollutants such as acid and basic dyes, heavy metals, phenolic compounds, various gaseous pollutants, and so on. Numerous studies on adsorption properties of various low-cost adsorbents, such as agricultural wastes and its based activated carbons, have been reported in recent years. Studies have shown that oil palm-based adsorbent, among the low-cost adsorbents mentioned, is the most promising adsorbent for removing water pollutants. Further, these bioadsorbents can be chemically modified for better efficiency and can undergo multiple reuses to enhance their applicability at an industrial scale. It is evident from a literature survey of more than 100 recent papers that low-cost adsorbents have demonstrated outstanding removal capabilities for various pollutants. The conclusion is been drawn from the reviewed literature, and suggestions for future research are proposed.

Cost analysis of seawater uranium recovered by a polymeric adsorbent system

International Nuclear Information System (INIS)

Schneider, E.; Lindner, H.; Sachde, D.; Flicker, M.

2014-01-01

In tandem with its adsorbent development and marine testing efforts, the United States Department of Energy, Office of Nuclear Energy, routinely updates and expands its cost analysis of technologies for extracting uranium from seawater. If informed by repeatable data from field tests, a rigorous cost analysis can convincingly establish seawater uranium as a “backstop” to conventional uranium resources. A backstop provides an essentially unlimited supply of an otherwise exhaustible resource. Its role is to remove the uncertainty around the long-term sustainability of the resource. The cost analysis ultimately aims to demonstrate a uranium production cost that is sustainable for the nuclear power industry, with no insurmountable technical or environmental roadblocks. It is also a tool for guiding further R&D, identifying inputs and performance factors where further development would offer the greatest reduction in costs and/or uncertainties. A life cycle discounted cash flow methodology is used to calculate the uranium production cost and its uncertainty from the costs of fundamental inputs including chemicals and materials, labor, equipment, energy carriers and facilities. The inputs themselves are defined by process flow models of the adsorbent fabrication and grafting, mooring at sea, recovery, and elution and purification steps in the seawater uranium recovery process. Pacific Northwest National Laboratory (PNNL) has carried out marine tests of the Oak Ridge National Laboratory amidoxime grafted polymer adsorbent in natural seawater. Multiple test campaigns demonstrated that after 60 days of immersion the uranium uptake averaged 3090 ± 310 μg U/g of adsorbent. Past ocean experiments on similar material by the Japan Atomic Energy Agency (JAEA) demonstrated that the adsorbent may be used in the sea six times before being replaced, with 5% uptake degradation per reuse. The mooring and recovery system envisioned for the adsorbent is similar to one proposed by

A Multi-technique Characterization of Adsorbed Protein Films: Orientation and Structure by ToF-SIMS, NEXAFS, SFG, and XPS

Science.gov (United States)

Baio, Joseph E.

immobilization schemes. This protein contained both a hexahistidine tag and a cysteine residue, introduced at opposite ends of the HuLys Fv, for immobilization onto nitrilotriacetic acid (NTA) and maleimide oligo- (ethylene glycol) (MEG)-terminated substrates. The thiol group on the cysteine residue selectively binds to the MEG groups, while the his-tag selectively binds to the Ni-loaded NTA groups. XPS was used to monitor protein coverage on both surfaces by following the change in the nitrogen atomic %. The ToF-SIMS data provided a clear differentiation between the two samples due to the intensity differences of secondary ions originating from asymmetrically located amino acids in HuLys Fv. Indicating that the HuLys Fv fragment when adsorbed into the NTA and MEG substrates will be induced into two different orientations. On the NTA substrate the protein's binding site is accessible, while on the MEG substrate the binding site is oriented towards the surface. By taking advantage of the electron pathway through the heme group in cytochrome c (CytoC) electrochemists have built sensors based upon CytoC immobilized onto functionalized metal electrodes. When immobilized onto a charged surface, CytoC, with its distribution of lysine and glutamate residues around its surface, should orient and form a well-ordered protein film. Here a detailed examination of CytoC orientation when electrostatically immobilized onto both amine (NH 3+) and carboxyl (COO-) functionalized gold is presented. Again, protein coverage, on both surfaces, was monitored by the change in the atomic % N, as determined by XPS. ToF-SIMS data demonstrated a clear separation between the two samples based on the intensity differences of secondary ions stemming from amino acids located asymmetrically within CytoC, indicating opposite orientations of the protein on the two different surfaces. Spectral features within the in situ sum frequency generation vibrational spectra, acquired for the protein interacting with

A theoretical study of adsorbate-adsorbate interactions on Ru(0001)

DEFF Research Database (Denmark)

Mortensen, Jens Jørgen; Hammer, Bjørk; Nørskov, Jens Kehlet

1998-01-01

the barrier for dissociation, whereas S will increase it. The interaction with alkali atoms is mainly of an electrostatic nature. The poisoning by S is due to two kinds of repulsive interactions: a Pauli repulsion and a reduced covalent bond strength between the adsorbate and the surface d-electrons. In order...... to investigate these different interactions in more detail, we look at three different species (N atoms, and terminally bonded N(2) and CO) and use them as probes to study their interaction with two modifier atoms (Na and S). The two modifier atoms have very different properties, which allows us to decouple...

An ultrathin polymer coating of carboxylate self-assembled monolayer adsorbed on passivated iron to prevent iron corrosion in 0.1 M Na2SO4

International Nuclear Information System (INIS)

Aramaki, Kunitsugu; Shimura, Tadashi

2010-01-01

For preparing an ultrathin two-dimensional polymer coating adsorbed on passivated iron, a 16-hydroxyhexadecanoate ion HO(CH 2 ) 15 CO 2 - self-assembled monolayer (SAM) was modified with 1,2-bis(triethoxysilyl)ethane (C 2 H 5 O) 3 Si(CH 2 ) 2 Si(OC 2 H 5 ) 3 and octadecyltriethoxysilane C 18 H 37 Si(OC 2 H 5 ) 3 . Protection of passivated iron against passive film breakdown and corrosion of iron was investigated by monitoring of the open-circuit potential and repeated polarization measurements in an aerated 0.1 M Na 2 SO 4 solution during immersion for many hours. The time required for passive film breakdown of the polymer-coated electrode was markedly higher in this solution than that of the passivated one, indicating protection of the passive film from breakdown by coverage with the polymer coating. The protective efficiencies of the passive film covered with the coating were extremely high, more than 99.9% in 0.1 M Na 2 SO 4 before the passive film was broken down, showing prominent cooperative suppression of iron corrosion in the solution by coverage with the passive film and polymer coating. The polymer-coated surface was characterized by contact angle measurement and electron-probe microanalysis (EPMA). Prevention of passive film breakdown and iron corrosion for the polymer-coated electrode healed in 0.1 M NaNO 3 was also examined in 0.1 M Na 2 SO 4 .

Evaluating of arsenic(V) removal from water by weak-base anion exchange adsorbents.

Science.gov (United States)

Awual, M Rabiul; Hossain, M Amran; Shenashen, M A; Yaita, Tsuyoshi; Suzuki, Shinichi; Jyo, Akinori

2013-01-01

Arsenic contamination of groundwater has been called the largest mass poisoning calamity in human history and creates severe health problems. The effective adsorbents are imperative in response to the widespread removal of toxic arsenic exposure through drinking water. Evaluation of arsenic(V) removal from water by weak-base anion exchange adsorbents was studied in this paper, aiming at the determination of the effects of pH, competing anions, and feed flow rates to improvement on remediation. Two types of weak-base adsorbents were used to evaluate arsenic(V) removal efficiency both in batch and column approaches. Anion selectivity was determined by both adsorbents in batch method as equilibrium As(V) adsorption capacities. Column studies were performed in fixed-bed experiments using both adsorbent packed columns, and kinetic performance was dependent on the feed flow rate and competing anions. The weak-base adsorbents clarified that these are selective to arsenic(V) over competition of chloride, nitrate, and sulfate anions. The solution pH played an important role in arsenic(V) removal, and a higher pH can cause lower adsorption capacities. A low concentration level of arsenic(V) was also removed by these adsorbents even at a high flow rate of 250-350 h(-1). Adsorbed arsenic(V) was quantitatively eluted with 1 M HCl acid and regenerated into hydrochloride form simultaneously for the next adsorption operation after rinsing with water. The weak-base anion exchange adsorbents are to be an effective means to remove arsenic(V) from drinking water. The fast adsorption rate and the excellent adsorption capacity in the neutral pH range will render this removal technique attractive in practical use in chemical industry.

Microporous carbonaceous adsorbents for CO2 separation via selective adsorption

KAUST Repository

Zhao, Yunfeng

2015-01-01

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

Adsorption behavior of lithium from seawater using manganese oxide adsorbent

International Nuclear Information System (INIS)

Wajima, Takaaki; Munakata, Kenzo; Uda, Tatsuhiko

2012-01-01

The deuterium-tritium (D-T) fusion reactor system is expected to provide the main source of electricity in the future. Large amounts of lithium will be required, dependent on the reactor design concept, and alternative resources should be found to provide lithium inventories for nuclear fusion plants. Seawater has recently become an attractive source of this element and the separation and recovery of lithium from seawater by co-precipitation, solvent extraction and adsorption have been investigated. Amongst these techniques, the adsorption method is suitable for recovery of lithium from seawater, because certain inorganic ion-exchange materials, especially spinel-type manganese oxides, show extremely high selectivity for the lithium ion. In this study, we prepared a lithium adsorbent (HMn 2 O 4 ) by elution of spinel-type lithium di-manganese-tetra-oxide (LiMn 2 O 4 ) and examined the kinetics of the adsorbent for lithium ions in seawater using a pseudo-second-order kinetic model. The intermediate, LiMn 2 O 4 , can be synthesized from LiOH·H 2 O and Mn 3 O 4 , from which the lithium adsorbent can subsequently be prepared via acid treatment., The adsorption kinetics become faster and the amount of lithium adsorbed on the adsorbent increases with increasing solution temperature. The thermodynamic values, ΔG 0 , ΔH 0 and ΔS 0 , indicate that adsorption is an endothermic and spontaneous process. (author)

Kinetics of conformational changes of fibronectin adsorbed onto model surfaces.

Science.gov (United States)

Baujard-Lamotte, L; Noinville, S; Goubard, F; Marque, P; Pauthe, E

2008-05-01

Fibronectin (FN), a large glycoprotein found in body fluids and in the extracellular matrix, plays a key role in numerous cellular behaviours. We investigate FN adsorption onto hydrophilic bare silica and hydrophobic polystyrene (PS) surfaces using Fourier transform infrared spectroscopy-attenuated total reflection (FTIR-ATR) in aqueous medium. Adsorption kinetics using different bulk concentrations of FN were followed for 2h and the surface density of adsorbed FN and its time-dependent conformational changes were determined. When adsorption occurs onto the hydrophilic surface, FN molecules keep their native conformation independent of the adsorption conditions, but the amount of adsorbed FN increases with time and the bulk concentration. Although the protein surface density is the same on the hydrophobic PS surface, this has a strong impact on the average conformation of the adsorbed FN layer. Indeed, interfacial hydration changes induced by adsorption onto the hydrophobic surface lead to a decrease in unhydrated beta-sheet content and cause an increase in hydrated beta-strand and hydrated random domain content of adsorbed FN. This conformational change is mainly dependent on the bulk concentration. Indeed, at low bulk concentrations, the secondary structures of adsorbed FN molecules undergo strong unfolding, allowing an extended and hydrated conformation of the protein. At high bulk concentrations, the molecular packing reduces the unfolding of the stereoregular structures of the FN molecules, preventing stronger spreading of the protein.

Heterogeneous ice nucleation

Energy Technology Data Exchange (ETDEWEB)

Bogdan, A. [Helsinki Univ. (Finland). Dept. of Physics

1994-12-31

The classical theory of heterogenous ice nucleation is reviewed in detail. The modelling of ice nucleation in the adsorbed water films on natural particles by analogous ice nucleation in adsorbed water films on the walls of porous media is discussed. Ice nucleation in adsorbed films of purewater and the HNO{sub 3}/H{sub 2}0 binary system on the surface of porous aerosol (SiO{sub 2}) was investigated using the method of NMR spectroscopy. The median freezing temperature and freezing temperature region were shown to be highly sensitive both to the average thickness of the adsorbed films and to the amount of adsorbed nitric acid. The character of the ice phase formation tends to approach that of bulk liquid with increasing adsorbed film thickness. Under the given conditions the thickness of the adsorbed films decreases with an increasing amount of adsorbed nitric acid molecules The molar concentration of nitric acid in the adsorbed films is very small (of the order of 10{sup -}3 10{sup -}2 (M/l)). Nitric acid molecules tend to adsorb on the surface of aerosol to a greater extent than in subsequent layers. The concentration is greatest in layers situated close to the surface and sharply decreases with the distance from the surface. The difference between the median freezing temperatures for adsorbed pure water and for the binary system was found to be about 9 K for films of equal thickness. This is about 150 times greater than the difference between the median freezing temperatures of bulk pure water and a solution with the same concentration of nitric acid. (orig.)

Fate of Trace Organic Compounds in Granular Activated Carbon (GAC Adsorbers for Drinking Water Treatment

Directory of Open Access Journals (Sweden)

Alexander Sperlich

2017-06-01

Full Text Available Granular activated carbon (GAC adsorbers for drinking water treatment were operated for approx. 14 months and the breakthrough of dissolved organic carbon (DOC and trace organic chemicals (TOrCs was monitored. Effluent concentration profiles of gabapentin and valsartan acid increase already at throughputs of <10,000 BV. The corresponding breakthrough curves flatten out without reaching the influent concentration level. This strongly indicates biological degradation of these substances in the GAC adsorbers under aerobic conditions, contributing to a more efficient use of GAC. The observed biodegradation in pilot GAC adsorbers also confirms recent reports of biodegradation of gabapentin and valsartan acid during managed aquifer recharge. Oxypurinol is comparatively well adsorbed and no breakthrough was observed during the experimental period. Adsorption capacity and breakthrough characteristics of oxypurinol appear very similar to carbamazepine. Breakthrough of GAC adsorbers operated with drinking water was compared to those of groundwater-fed adsorbers. The results show, that it is generally advisable to use previously aerated influents for GAC fixed-bed adsorbers because this can substantially improve biological removal of otherwise poorly adsorbable compounds and ensure full GAC accessibility for adsorbates by avoiding the undesirable formation of inorganic precipitates on adsorption sites.

Deodorisation effect of diamond-like carbon/titanium dioxide multilayer thin films deposited onto polypropylene

Energy Technology Data Exchange (ETDEWEB)

Ozeki, K., E-mail: ozeki@mx.ibaraki.ac.jp [Department of Mechanical Engineering, Ibaraki University, 4-12-1, Nakanarusawa, Hitachi, Ibaraki 316-8511 (Japan); Frontier Research Center for Applied Atomic Sciences, 162-1 Shirakata, Toukai, Ibaraki 319-1106 (Japan); Hirakuri, K.K. [Applied Systems Engineering, Graduate School of Science and Engineering, Tokyo Denki University, Ishizaka, Hatoyama, Hiki, Saitama 350-0394 (Japan); Masuzawa, T. [Department of Mechanical Engineering, Ibaraki University, 4-12-1, Nakanarusawa, Hitachi, Ibaraki 316-8511 (Japan)

2011-04-15

Many types of plastic containers have been used for the storage of food. In the present study, diamond-like carbon (DLC)/titanium oxide (TiO{sub 2}) multilayer thin films were deposited on polypropylene (PP) to prevent flavour retention and to remove flavour in plastic containers. For the flavour removal test, two types of multilayer films were prepared, DLC/TiO{sub 2} films and DLC/TiO{sub 2}/DLC films. The residual gas concentration of acetaldehyde, ethylene, and turmeric compounds in bottle including the DLC/TiO{sub 2}-coated and the DLC/TiO{sub 2}/DLC-coated PP plates were measured after UV radiation, and the amount of adsorbed compounds to the plates was determined. The percentages of residual gas for acetaldehyde, ethylene, and turmeric with the DLC/TiO{sub 2} coated plates were 0.8%, 65.2% and 75.0% after 40 h of UV radiation, respectively. For the DLC/TiO{sub 2}/DLC film, the percentages of residual gas for acetaldehyde, ethylene and turmeric decreased to 34.9%, 76.0% and 85.3% after 40 h of UV radiation, respectively. The DLC/TiO{sub 2}/DLC film had a photocatalytic effect even though the TiO{sub 2} film was covered with the DLC film.

Deodorisation effect of diamond-like carbon/titanium dioxide multilayer thin films deposited onto polypropylene

International Nuclear Information System (INIS)

Ozeki, K.; Hirakuri, K.K.; Masuzawa, T.

2011-01-01

Many types of plastic containers have been used for the storage of food. In the present study, diamond-like carbon (DLC)/titanium oxide (TiO 2 ) multilayer thin films were deposited on polypropylene (PP) to prevent flavour retention and to remove flavour in plastic containers. For the flavour removal test, two types of multilayer films were prepared, DLC/TiO 2 films and DLC/TiO 2 /DLC films. The residual gas concentration of acetaldehyde, ethylene, and turmeric compounds in bottle including the DLC/TiO 2 -coated and the DLC/TiO 2 /DLC-coated PP plates were measured after UV radiation, and the amount of adsorbed compounds to the plates was determined. The percentages of residual gas for acetaldehyde, ethylene, and turmeric with the DLC/TiO 2 coated plates were 0.8%, 65.2% and 75.0% after 40 h of UV radiation, respectively. For the DLC/TiO 2 /DLC film, the percentages of residual gas for acetaldehyde, ethylene and turmeric decreased to 34.9%, 76.0% and 85.3% after 40 h of UV radiation, respectively. The DLC/TiO 2 /DLC film had a photocatalytic effect even though the TiO 2 film was covered with the DLC film.

On the Morphology of the SDS Film on the Surface of Borosilicate Glass

Directory of Open Access Journals (Sweden)

Zih-Yao Shen

2017-05-01

Full Text Available Surfactant films on solid surfaces have attracted much attention because of their scientific interest and applications, such as surface treatment agent, or for micro- or nano-scale templates for microfluidic devices. In this study, anionic surfactant sodium dodecyl sulfate (SDS solutions with various charged inorganic salts was spread on a glass substrate and dried to form an SDS thin film. Atomic force microscopy (AFM was employed to observe the micro-structure of the SDS thin film. The effects of inorganic salts on the morphology of the SDS film were observed and discussed. The results of experiments demonstrated that pure SDS film formed patterns of long, parallel, highly-ordered stripes. The existence of the inorganic salt disturbed the structure of the SDS film due to the interaction between the cationic ion and the anionic head groups of SDS. The divalent ion has greater electrostatic interaction with anionic head groups than that of the monovalent ion, and causes a gross change in the morphology of the SDS film. The height of the SDS bilayer measured was consistent with the theoretical value, and the addition of the large-sized monovalent ion would lead to lowering the height of the adsorbed structures.

Extraction of uranium from sea water by means of fibrous complex adsorbents

International Nuclear Information System (INIS)

Miyamatsu, Tokuhisa; Oguchi, Noboru; Kanchiku, Yoshihiko; Aoyagi, Takanobu

1982-01-01

Fibrous complex adsorbents for uranium extraction from sea water were prepared by introducing titanic acid or basic zinc carbonate as effective constituents into fibrous ion exchangers. A fibrous chelate type adsorbent was also tested. Among the adsorbents examined, the following ones demonstrated excellent properties for the recovery of uranium from sea water. a) A fibrous, weakly acidic cation exchanger was treated with titanyl sulfate in aqueous sulfuric acid solution, which was followed by neutralization to afford a fibrous adsorbent containing titanic acid (QC-1f(Ti)). The adsorption capacity for uranium in sea water was estimated by extrapolation to be 50μg-U/g-Ad or 1170 μg-U/g-Ti. b) A fibrous, strongly acidic cation exchanger was treated in a similar way to afford another type of fibrous adsorbent with titanic acid incorporated (QCS-Ti). The adsorption capacity was estimated by extrapolation to be 20-30 μg-U/g-Ad. (author)

Simulations of the Static Friction Due to Adsorbed Molecules

OpenAIRE

He, Gang; Robbins, Mark O.

2001-01-01

The static friction between crystalline surfaces separated by a molecularly thin layer of adsorbed molecules is calculated using molecular dynamics simulations. These molecules naturally lead to a finite static friction that is consistent with macroscopic friction laws. Crystalline alignment, sliding direction, and the number of adsorbed molecules are not controlled in most experiments and are shown to have little effect on the friction. Temperature, molecular geometry and interaction potenti...

Complementary roles of benzylpiperazine and iodine ‘vapor’ in the strong enhancement of orange photoluminescence from CuI(1 1 1) thin film

International Nuclear Information System (INIS)

Rawal, Takat B; Turkowski, Volodymyr; Rahman, Talat S

2014-01-01

We have employed density functional theory, corrected by the on-site electron–electron repulsion energy U, to clarify the mechanism behind the enhanced orange photoluminescence (PL) of a CuI(1 1 1) thin film conjugated with a benzylpiperazine (BZP) molecule in the presence of an iodine ‘vapor’ atom. Our results demonstrated that the adsorbed molecule and the ‘vapor’ atom play complementary roles in producing the PL. The latter, in attaching to the film surface, creates a hole-trapping surface state located ∼0.25 eV above the valence band-edge of the film, in good agreement with ∼0.2 eV reported in experiments. Upon photo-excitation of the BZP/CuI(1 1 1) system in the presence of surface iodine ‘vapor’ atoms, excited electrons are transferred into the conduction band of CuI, and holes are trapped by the ‘vapor’ atoms. These holes, in turn, quickly relax into the HOMO state of the BZP molecule, owing to the fact that the molecule adsorbs on the film surface in the immediate vicinity of a ‘vapor’ atom. Relaxed holes subsequently recombine with excited electrons in the conduction band of the CuI film, thereby producing a luminescence peak at ∼2.1 eV, in qualitative agreement with experimental findings. (paper)

Theory and simulation of epitaxial rotation. Light particles adsorbed on graphite

DEFF Research Database (Denmark)

Vives, E.; Lindgård, P.-A.

1993-01-01

We present a theory and Monte Carlo simulations of adsorbed particles on a corrugated substrate. We have focused on the case of rare gases and light molecules, H-2 and D2, adsorbed on graphite. The competition between the particle-particle and particle-substrate interactions gives rise to frustra...... found a modulated 4 x 4 structure. Energy, structure-factor intensities, peak positions, and epitaxial rotation angles as a function of temperature and coverage have been determined from the simulations. Good agreement with theory and experimental data is found.......We present a theory and Monte Carlo simulations of adsorbed particles on a corrugated substrate. We have focused on the case of rare gases and light molecules, H-2 and D2, adsorbed on graphite. The competition between the particle-particle and particle-substrate interactions gives rise...... between the commensurate and incommensurate phase for the adsorbed systems. From our simulations and our theory, we are, able to understand the gamma phase of D2 as an ordered phase stabilized by disorder. It can be described as a 2q-modulated structure. In agreement with the experiments, we have also...

Radiation Effects in Hydrogen-Laden Porous Water Ice Films: Implications for Interstellar Ices

Science.gov (United States)

Raut, Ujjwal; Baragiola, Raul; Mitchell, Emma; Shi, Jianming

H _{2} is the dominant gas in the dense clouds of the interstellar medium (ISM). At densities of 10 (5) cm (-3) , an H _{2} molecule arrives at the surface of a 0.1 mum-sized, ice-covered dust grain once every few seconds [1]. At 10 K, H _{2} can diffuse into the pores of the ice mantle and adsorb at high-energy binding sites, loading the ice with hydrogen over the lifetime of the cloud. These icy grains are also impacted by galactic cosmic rays and stellar winds (in clouds with embedded protostar). Based on the available cosmic proton flux spectrum [2], we estimate a small impact rate of nearly 1 hit per year on a 0.1 μm sized grain, or 10 (-7) times the impact frequency of the neutral H _{2}. The energy deposited by such impacts can release the adsorbed H _{2} into the gas phase (impact desorption or sputtering). Recently, we have reported on a new process of ion-induced enhanced adsorption, where molecules from the gas phase are incorporated into the film when irradiation is performed in the presence of ambient gas [3]. The interplay between ion-induced ejection and adsorption can be important in determining the gas-solid balance in the ISM. To understand the effects of cosmic rays/stellar winds impacts on interstellar ice immersed in H _{2} gas, we have performed irradiation of porous amorphous ice films loaded with H _{2} through co-deposition or adsorption following growth. The irradiations were performed with 100 keV H (+) using fluxes of 10 (10) -10 (12) H (+) cm (-2) s (-1) at 7 K, in presence of ambient H _{2} at pressures ranging from 10 (-5) to 10 (-8) Torr. Our initial results show a net loss in adsorbed H _{2} during irradiation, from competing ion-induced ejection and adsorption. The H _{2} loss per ion decreases exponentially with fluence, with a cross-section of 10 (-13) cm (2) . In addition to hydrogen removal, irradiation also leads to trapping of H _{2} in the ice film, from closing of the pores during irradiation [4]. As a result, 2.6 percent

Oil adsorbing package, also procedure to remove oil from a water surface

Energy Technology Data Exchange (ETDEWEB)

1971-05-01

A method is given to remove oil from water to prevent water pollution. Use is made of an oil-adsorbing packet having a specific gravity which is lower than the specific gravity of water. The hull is manufactured from any material which is not a water-insoluble nonpolar material. The hull is partly permeable to water and encloses a solid oil-adsorbing compound having a large adsorbing surface. (10 claims)

Molecular dynamics simulations of disjoining pressure effects in ultra-thin water films on a metal surface

Science.gov (United States)

Hu, Han; Sun, Ying

2013-11-01

Disjoining pressure, the excess pressure in an ultra-thin liquid film as a result of van der Waals interactions, is important in lubrication, wetting, flow boiling, and thin film evaporation. The classic theory of disjoining pressure is developed for simple monoatomic liquids. However, real world applications often utilize water, a polar liquid, for which fundamental understanding of disjoining pressure is lacking. In the present study, molecular dynamics (MD) simulations are used to gain insights into the effect of disjoining pressure in a water thin film. Our MD models were firstly validated against Derjaguin's experiments on gold-gold interactions across a water film and then verified against disjoining pressure in an argon thin film using the Lennard-Jones potential. Next, a water thin film adsorbed on a gold surface was simulated to examine the change of vapor pressure with film thickness. The results agree well with the classic theory of disjoining pressure, which implies that the polar nature of water molecules does not play an important role. Finally, the effects of disjoining pressure on thin film evaporation in nanoporous membrane and on bubble nucleation are discussed.

Electron-stimulated desorption of cesium atoms from cesium layers adsorbed on gold-covered tungsten

Energy Technology Data Exchange (ETDEWEB)

Ageev, V N; Kuznetsov, Yu A; Potekhina, N D, E-mail: kuznets@ms.ioffe.r [A F Ioffe Physico-Technical Institute, Russian Academy of Sciences, 194021, St Petersburg (Russian Federation)

2010-03-03

The electron-stimulated desorption (ESD) yields and energy distributions (ED) for neutral cesium atoms have been measured from cesium layers adsorbed on a gold-covered tungsten surface as a function of electron energy, gold film thickness, cesium coverage and substrate temperature. The measurements have been carried out using a time-of-flight method and surface ionization detector in the temperature range 160-300 K. A measurable ESD yield for Cs atoms is observed only after deposition of more than one monolayer of gold and cesium on a tungsten surface at a temperature T = 300 K, which is accompanied by the formation of a CsAu semiconductor film covered with a cesium atom monolayer. The Cs atom ESD yield as a function of incident electron energy has a resonant character and consists of two peaks, the appearance of which depends on both electron energy and substrate temperature. The first peak has an appearance threshold at an electron energy of 57 eV and a substrate temperature of 300 K that is due to Au 5p{sub 3/2} core level excitation in the substrate. The second peak appears at an electron energy of 24 eV and a substrate temperature of 160 K. It is associated with a Cs 5s core level excitation in the Cs adsorbed layer. The Au 5p{sub 3/2} level excitation corresponds to a single broad peak in the ED with a maximum at a kinetic energy of 0.45 eV at a substrate temperature T = 300 K, which is split into two peaks with maxima at kinetic energies of 0.36 and 0.45 eV at a substrate temperature of 160 K, associated with different Cs atom ESD channels. The Cs 5s level excitation leads to an ED for Cs atoms with a maximum at a kinetic energy of approx 0.57 eV which exists only at T < 240 K and low Cs concentrations. The mechanisms for all the Cs atom ESD channels are proposed and compared with the Na atom ESD channels in the Na-Au-W system.

Investigations into the Reusability of Amidoxime-Based Polymeric Adsorbents for Seawater Uranium Extraction

Energy Technology Data Exchange (ETDEWEB)

Kuo, Li-Jung [Marine; Pan, Horng-Bin [Department; Wai, Chien M. [Department; Byers, Margaret F. [Nuclear; Schneider, Erich [Nuclear; Strivens, Jonathan E. [Marine; Janke, Christopher J. [Oak Ridge National Laboratory, P.O. Box 2008, Oak Ridge, Tennessee 37831, United States; Das, Sadananda [Oak Ridge National Laboratory, P.O. Box 2008, Oak Ridge, Tennessee 37831, United States; Mayes, Richard T. [Oak Ridge National Laboratory, P.O. Box 2008, Oak Ridge, Tennessee 37831, United States; Wood, Jordana R. [Marine; Schlafer, Nicholas [Marine; Gill, Gary A. [Marine

2017-09-29

The ability to re-use amidoxime-based polymeric adsorbents is a critical component in reducing the overall cost of the technology to extract uranium from seawater. This report describes an evaluation of adsorbent reusability in multiple re-use (adsorption/stripping) cycles in real seawater exposures with potassium bicarbonate (KHCO3) elution using several amidoxime-based polymeric adsorbents. The KHCO3 elution technique achieved ~100% recovery of uranium adsorption capacity in the first re-use. Subsequent re-uses showed significant drops in adsorption capacity. After the 4th re-use with the ORNL AI8 adsorbent, the 56-day adsorption capacity dropped to 28% of its original capacity. FTIR spectra revealed that there was a conversion of the amidoxime ligands to carboxylate groups during extended seawater exposure, becoming more significant with longer the exposure time. Ca and Mg adsorption capacities also increased with each re-use cycle supporting the hypothesis that long term exposure resulted in converting amidoxime to carboxylate, enhancing the adsorption of Ca and Mg. Shorter seawater exposure (adsorption/stripping) cycles (28 vs. 42 days) had higher adsorption capacities after re-use, but the shorter exposure cycle time did not produce an overall better performance in terms of cumulative exposure time. Recovery of uranium capacity in re-uses may also vary across different adsorbent formulations. Through multiple re-use the adsorbent AI8 can harvest 10 g uranium/kg adsorbent in ~140 days, using a 28-day adsorption/stripping cycle, a performance much better than would be achieved with a single use of the adsorbent through very long-term exposure (saturation capacity = 7.4 g U/kg adsorbent). A time dependent seawater exposure model to evaluate the cost associated with reusing amidoxime-based adsorbents in real seawater exposures was developed. The cost to extract uranium from seawater ranged from $610-830/kg U was predicted. Model simulation suggests that a short

Growth Of Organic Semiconductor Thin Films with Multi-Micron Domain Size and Fabrication of Organic Transistors Using a Stencil Nanosieve.

Science.gov (United States)

Fesenko, Pavlo; Flauraud, Valentin; Xie, Shenqi; Kang, Enpu; Uemura, Takafumi; Brugger, Jürgen; Genoe, Jan; Heremans, Paul; Rolin, Cédric

2017-07-19

To grow small molecule semiconductor thin films with domain size larger than modern-day device sizes, we evaporate the material through a dense array of small apertures, called a stencil nanosieve. The aperture size of 0.5 μm results in low nucleation density, whereas the aperture-to-aperture distance of 0.5 μm provides sufficient crosstalk between neighboring apertures through the diffusion of adsorbed molecules. By integrating the nanosieve in the channel area of a thin-film transistor mask, we show a route for patterning both the organic semiconductor and the metal contacts of thin-film transistors using one mask only and without mask realignment.

Copper and zinc removal from roof runoff: from research to full-scale adsorber systems.

Science.gov (United States)

Steiner, M; Boller, M

2006-01-01

Large, uncoated copper and zinc roofs cause environmental problems if their runoff is infiltrated into the underground or discharged into receiving waters. Since source control is not always feasible, barrier systems for efficient copper and zinc removal are recommended in Switzerland. During the last few years, research carried out in order to test the performance of GIH-calcite adsorber filters as a barrier system. Adsorption and mass transport processes were assessed and described in a mathematical model. However, this model is not suitable for practical design, because it does not give explicit access to design parameters such as adsorber diameter and adsorber bed depth. Therefore, for e.g. engineers, an easy to use design guideline for GIH-calcite adsorber systems was developed, mainly based on the mathematical model. The core of this guideline is the design of the depth of the GIH-calcite adsorber layer. The depth is calculated by adding up the GIH depth for sorption equilibrium and the depth for the mass transfer zone (MTZ). Additionally, the arrangement of other adsorber system components such as particle separation and retention volume was considered in the guideline. Investigations of a full-scale adsorber confirm the successful application of this newly developed design guideline for the application of GIH-calcite adsorber systems in practice.

Silkworm exuviae-A new non-conventional and low-cost adsorbent for removal of methylene blue from aqueous solutions

International Nuclear Information System (INIS)

Chen Hao; Zhao Jie; Dai Guoliang

2011-01-01

In this paper, silkworm exuviae (SE) waste, an agricultural waste available in large quantity in China, was utilized as low-cost adsorbent to remove basic dye (methylene blue, MB) from aqueous solution by adsorption. Kinetic data and sorption equilibrium isotherms were carried out in batch process. The adsorption kinetic experiments revealed that MB adsorption onto SE for different initial dye concentrations all followed pseudo-second order kinetics and were mainly controlled by the film diffusion mechanism. Batch equilibrium results at different temperatures suggest that MB adsorption onto SE can be described perfectly with Freundlich isotherm model compared with Langmuir and D-R isotherm models, and the characteristic parameters for each adsorption isotherm were also determined. Thermodynamic parameters calculated show the adsorption process has been found to be endothermic in nature. The analysis for the values of the mean free energies of adsorption (E a ), the Gibbs free energy (ΔG 0 ) and the effect of ionic strength all demonstrate that the whole adsorption process is mainly dominated by ion-exchange mechanism, which has also been verified by variations in FT-IR spectra and pH value before and after adsorption and desorption studies. The results reveal that SE can be employed as a low-cost alternative to other adsorbents for MB adsorption.

Comparative study of selenite adsorption on carbon based adsorbents and activated alumina.

Science.gov (United States)

Jegadeesan, G; Mondal, K; Lalvani, S B

2003-08-01

The sorption characteristics of carbon-based adsorbents such as activated carbon and chitin for the removal of selenite, Se (IV), an anionic, hazardous contaminant, are compared with those of alpha and gamma alumina. Batch experiments were conducted to determine the influence of pH, concentration of adsorbate, adsorbent loading and temperature on the sorption characteristics of the adsorbents. Generally, low pH of the solution resulted in favorable selenium removal. With the exception of activated carbon, uptakes decreased with increase in temperature. In comparison, chitin was found to be far less effective for the removal of Se (IV) from aqueous solutions. The data also showed that gamma alumina provided higher selenium removal percentages (99%) compared to alpha alumina (94%), activated carbon (87%) and chitin (49%). The selenite removal was found to decrease with increasing initial Se (IV) concentration in the solution. Adsorption capacities of the adsorbents are reported in terms of their Langmuir adsorption isotherms. The adsorption capacity (on unit mass basis) of the adsorbents for selenite is in the order: chitin (specific area (sa) = 9.58 m2 g(-1)) activated carbon (sa = 96.37 m2 g(-1)) < alpha alumina (sa = 6 m2 g(-1)) < gamma alumina (sa = 150 m2 g(-1)).

A comparative study of the adsorption and oxidation of L-alanine and L-serine on Au(1 0 0), Au(1 1 1) and gold thin film electrodes in acid media

International Nuclear Information System (INIS)

Sandoval, Andrea P.; Orts, José Manuel; Rodes, Antonio; Feliu, Juan M.

2013-01-01

The adsorption and oxidation of L-alanine and L-serine at Au(1 1 1) and Au(1 0 0) single crystal and evaporated thin-film electrodes with preferential (1 1 1) orientation was studied in perchloric acid solutions. For this purpose, cyclic voltammetry experiments were combined with external reflection infrared spectroscopy (gold single crystals) and surface-enhanced infrared reflection–absorption spectroscopy under attenuated total reflection conditions (ATR-SEIRAS) (gold thin films). In addition, theoretical harmonic vibrational frequencies, obtained from B3LYP/LANL2DZ, 6-31+G(d) calculations for the zwitterionic species adsorbed on Au clusters with (1 1 1) orientation, were used to interpret the experimental spectra. The optimized geometry obtained from DFT calculations for the corresponding zwitterion plus a water molecule, under the application of an external electric field of 0.01 a.u. corresponds to a bidentate asymmetrical bridge adsorption configuration. The absence of an adsorbate band for the asymmetric OCO stretching in the experimental infrared spectra confirms the bidentate bonding of the adsorbed zwitterion through the oxygen atoms of the carboxylate group irrespective of the crystallographic orientation of the electrode surface, the adsorbate coverage and the electrode potential. In addition to typical interfacial water bands associated to perchlorate anions, which are co-adsorbed in order to compensate the positive charge of the ammonium group, the ATR-SEIRA spectra also show bands around 2950 cm −1 that can be related to the formation of hydrogen bonds between interfacial water and the ammonium group of the adsorbed zwitterion. The voltammetric experiments have shown that, as in the case of platinum electrodes, L-serine oxidizes at lower potentials than L-alanine. Under these conditions, the in situ infrared experiments show the formation of carbon dioxide and adsorbed cyanide as oxidation products of L-serine. In the case of L-alanine, only

Solid adsorbents for removal of hydrogen sulphide from hot gas

Energy Technology Data Exchange (ETDEWEB)

Furimsky, E.; Yumura, Motoo

1986-04-01

A wide range of solids have been tested as potential adsorbents for H/sub 2/S removal from hot gas. These solids can be divided into two main groups, i.e., the adsorbents containing alkaline earth metals and those containing transition metals. Among the former, calcium oxide and naturally occurring materials such as limestone, dolomite and calcium silicate have attracted a great deal of attention. The adsorbents of the second group include iron oxide alone or in combination with some supports, zinc oxide, zinc ferrite and manganese oxide. The materials containing both the alkaline earth metals and transition metals, e.g., manganese nodules, fly ash and the reject from the aluminium industry (red mud) have been evaluated as well.

Citrus paradisi: an effective bio-adsorbent for arsenic (v) remediation

International Nuclear Information System (INIS)

Khaskheli, M.I.; Memon, S.Q.; Parveen, S.

2014-01-01

In the present study As(V) was removed by citrus paradise (grape fruit) peel. Kinetics of the adsorption reaction was analyzed by the Pseudo second order and Morris-weber equations. Freundlich and Langmuir isotherm models were utilized for understanding of the relationship between the arsenic ions and citrus paradise peel adsorbent. The maximum measured uptake capacity of citrus paradise was 37.76 mg.g/sup -1/ at pH 4. FT-IR characterization of unloaded and As (V) loaded citrus paradisi peel adsorbent showed the participation of carbonyl (CO) and hydroxyl (OH) groups in adsorption process. The proposed citrus paradis peel adsorbent with optimized parameters was used for the removal of arsenic from arsenic contaminated real water samples. (author)

An eco-friendly approach for heavy metal adsorbent regeneration using CO2-responsive molecular octopus.

Science.gov (United States)

Bai, Yu; Liang, Yen Nan; Hu, Xiao

2017-10-01

Perennial problems of adsorption in wastewater treatment include adsorbent recycling, generation of waste sludge and secondary pollution because harmful concentrated acids, bases or strong chelators are often used for adsorbent regeneration and adsorbate recovery. We report, for the first time, an eco-friendly regeneration concept demonstrated with a CO 2 -responsive octopus-like polymeric adsorbent. Various heavy metals can be scavenged at very high Q e by such adsorbent through coordination. Most importantly, the rapid and complete regeneration of the adsorbent and recovery of the heavy metal ions can be readily achieved by CO 2 bubbling within a few minutes under mild conditions, i.e., room temperature and atmospheric pressure. The adsorbent can then be restored to its adsorptive state and reused upon removal of CO 2 by simply bubbling another gas. This eco-friendly, effective, ultra-fast and repeatable CO 2 -triggered regeneration process using CO 2 -responsive adsorbent with versatile structure, morphology or form can be incorporated into a sustainable closed-loop wastewater treatment process to solve the perennial problems. Copyright © 2017 Elsevier Ltd. All rights reserved.

Single stage batch adsorber design for efficient Eosin yellow removalby polyaniline coated ligno-cellulose

CSIR Research Space (South Africa)

Debnath, S

2015-01-01

Full Text Available Polyaniline-coated lignin-based adsorbent (PLC) was synthesized and used for uptake of reactive dye eosin yellow (EY) from aqueous solution. The adsorption capability of the adsorbent was found to be more effective than the unmodified adsorbent (LC...

Diazonium-derived aryl films on gold nanoparticles: evidence for a carbon-gold covalent bond.

Science.gov (United States)

Laurentius, Lars; Stoyanov, Stanislav R; Gusarov, Sergey; Kovalenko, Andriy; Du, Rongbing; Lopinski, Gregory P; McDermott, Mark T

2011-05-24

Tailoring the surface chemistry of metallic nanoparticles is generally a key step for their use in a wide range of applications. There are few examples of organic films covalently bound to metal nanoparticles. We demonstrate here that aryl films are formed on gold nanoparticles from the spontaneous reduction of diazonium salts. The structure and the bonding of the film is probed with surface-enhanced Raman scattering (SERS). Extinction spectroscopy and SERS show that a nitrobenzene film forms on gold nanoparticles from the corresponding diazonium salt. Comparison of the SERS spectrum with spectra computed from density functional theory models reveals a band characteristic of a Au-C stretch. The observation of this stretch is direct evidence of a covalent bond. A similar band is observed in high-resolution electron energy loss spectra of nitrobenzene layers on planar gold. The bonding of these types of films through a covalent interaction on gold is consistent with their enhanced stability observed in other studies. These findings provide motivation for the use of diazonium-derived films on gold and other metals in applications where high stability and/or strong adsorbate-substrate coupling are required.

Theoretical Insight of Physical Adsorption for a Single Component Adsorbent + Adsorbate System: II. The Henry Region

KAUST Repository

Chakraborty, Anutosh; Saha, Bidyut Baran; Ng, Kim Choon; Koyama, Shigeru; Srinivasan, Kandadai

2009-01-01

evaluated and compared with experimental data. It is found that the adsorbents with higher specific surface areas tend to possess lower heat of adsorption (ΔH°) at the Henry regime. In this paper, we have established the definitive relation between Ai and ΔH

Ultrafast electron dynamics at alkali/ice structures adsorbed on a metal surface

International Nuclear Information System (INIS)

Meyer, Michael

2011-01-01

The goal of this work is to study the interaction between excess electrons in water ice structures adsorbed on metal surfaces and other charged or neutral species, like alkali ions, or chemically reactive molecules, like chlorofluorocarbons (CFC), respectively. The excess electrons in the ice can interact with the ions directly or indirectly via the hydrogen bonded water molecules. In both cases the presence of the alkali influences the population, localization, and lifetime of electronic states of excess electrons in the ice adlayer. These properties are of great relevance when considering the highly reactive character of the excess electrons, which can mediate chemical reactions by dissociative electron attachment (DEA). The influence of alkali adsorption on electron solvation and transfer dynamics in ice structures is investigated for two types of adsorption configurations using femtosecond time-resolved two-photon photoelectron spectroscopy. In the first system alkali atoms are coadsorbed on top of a wetting amorphous ice film adsorbed on Cu(111). At temperatures between 60 and 100 K alkali adsorption leads to the formation of positively charged alkali ions at the ice/vacuum interface. The interaction between the alkali ions at the surface and the dipole moments of the surrounding water molecules results in a reorientation of the water molecules. As a consequence new electron trapping sites, i.e. at local potential minima, are formed. Photoinjection of excess electrons into these alkali-ion covered amorphous ice layers, results in the trapping of a solvated electron at an alkali-ion/water complex. In contrast to solvation in pure amorphous ice films, where the electrons are located in the bulk of the ice layer, solvated electrons at alkali-ion/water complexes are located at the ice/vacuum interface. They exhibit lifetimes of several picoseconds and show a fast energetic stabilization. With ongoing solvation, i.e. pump-probe time delay, the electron transfer is

The synthesis of a new type adsorbent for the removal of toxic gas by radiation-induced graft polymerization

International Nuclear Information System (INIS)

Okamoto, Jiro; Sugo, Takanobu

1990-01-01

A new type of adsorbent containing sulfuric acid group for the removal of ammonia gas was synthesized by radiation-induced graft polymerization of styrene onto fibrous and nonwoven type polypropylene followed by sulufonation with chlorosulfonic acid. The rate of the adsorption of ammonia gas by H-type adsorbent is independent of the ion-exchange capacity. The amount of ammonia gas adsorbed by the chemical adsorption was dependent on the ion-exchange capacity of H-type fibrous adsorbent and was kept constant value in spite of the equilibrium pressure of ammonia gas. Cu(II)- and Ni(II)-types fibrous adsorbent were prepared by the ion exchange reaction of Na-type fibrous adsorbent with metal nitrate solutions. Although, the rate of adsorption of ammonia gas by metal-type fibrous adsorbent is lower than that of H-type adsorbent, the amount of ammonia gas adsorbed increases compared to H-type adsorbent with the same ion exchange capacity. It was related to the highest coordination number of metal ion. The ratio of the number of ammonia molecules adsorbed chemically and the number of metal ion adsorbed in fibrous adsorbent was 4 for Cu-type and 6 for Ni-type fibrous adsorbent, respectively. (author)

Preparation and characterization of sponge film made from feathers

Energy Technology Data Exchange (ETDEWEB)

Zhuang, Yuan; Wu, Xiaoqian [College of Environmental Science and Engineering, Donghua University, Shanghai 201620 (China); Cao, Zhangjun [College of Chemistry, Chemical Engineering and Biotechnology, Donghua University, Shanghai 201620 (China); Zhao, Xiaoxiang; Zhou, Meihua [College of Environmental Science and Engineering, Donghua University, Shanghai 201620 (China); Gao, Pin, E-mail: gaopin@mail.dhu.edu.cn [College of Environmental Science and Engineering, Donghua University, Shanghai 201620 (China)

2013-12-01

Feather wastes generated from poultry farms will pose a problem for disposal, but they are sustainable resources of keratin. Reduction is one of the commonly used methods to obtain soluble keratin from feather. However, the residues generated during feather reduction reaction were rarely investigated. In this study, the residues were transformed into a porous and flexible sponge film by freeze-drying without pretreatment or addition of cross-linking agents. Glycerol was used to alter the physical and chemical characteristics of the sponge film. The film was characterized with a fiber strong stretch instrument, a Fourier transform infrared spectrophotometer, scanning electron microscopy, an elemental analyzer, a differential scanning calorimeter and an automatic air permeability apparatus. Tensile strength and melting point of the sponge film with the optimum glycerol content were 6.2 MPa and 170 °C respectively. Due to air permeability of 368 mm/s, the film can potentially be used in medicine, biology, textile, environmental technology, and so on. It is ecologically friendly and will produce additional benefits from the renewable materials. The film was utilized as adsorbents to remove Cr(VI) from aqueous solutions and as a filtering material for air pollution. Its maximum Cr(VI) uptake capacity was about 148.8 mg/g and the removal rate of PM{sub 10} was 98.3%. - Graphical abstract: The reduction residues were made into a smooth, elastic, porous and flexible sponge film through freeze drying, no pretreatment and no cross-linking agent added. - Highlights: • The residue from feather waste reduction was turned into a sponge film. • A glycerol content of 5% produced a sponge with the optimum characteristics. • The sponge was uniform, stable up to 160 °C, and had an air permeability of 368 mm/s. • Feather-derived sponge film has potential applications in medicine and technology.

Preparation and characterization of sponge film made from feathers

International Nuclear Information System (INIS)

Zhuang, Yuan; Wu, Xiaoqian; Cao, Zhangjun; Zhao, Xiaoxiang; Zhou, Meihua; Gao, Pin

2013-01-01

Feather wastes generated from poultry farms will pose a problem for disposal, but they are sustainable resources of keratin. Reduction is one of the commonly used methods to obtain soluble keratin from feather. However, the residues generated during feather reduction reaction were rarely investigated. In this study, the residues were transformed into a porous and flexible sponge film by freeze-drying without pretreatment or addition of cross-linking agents. Glycerol was used to alter the physical and chemical characteristics of the sponge film. The film was characterized with a fiber strong stretch instrument, a Fourier transform infrared spectrophotometer, scanning electron microscopy, an elemental analyzer, a differential scanning calorimeter and an automatic air permeability apparatus. Tensile strength and melting point of the sponge film with the optimum glycerol content were 6.2 MPa and 170 °C respectively. Due to air permeability of 368 mm/s, the film can potentially be used in medicine, biology, textile, environmental technology, and so on. It is ecologically friendly and will produce additional benefits from the renewable materials. The film was utilized as adsorbents to remove Cr(VI) from aqueous solutions and as a filtering material for air pollution. Its maximum Cr(VI) uptake capacity was about 148.8 mg/g and the removal rate of PM 10 was 98.3%. - Graphical abstract: The reduction residues were made into a smooth, elastic, porous and flexible sponge film through freeze drying, no pretreatment and no cross-linking agent added. - Highlights: • The residue from feather waste reduction was turned into a sponge film. • A glycerol content of 5% produced a sponge with the optimum characteristics. • The sponge was uniform, stable up to 160 °C, and had an air permeability of 368 mm/s. • Feather-derived sponge film has potential applications in medicine and technology

Casein Aggregates Built Step-by-Step on Charged Polyelectrolyte Film Surfaces Are Calcium Phosphate-cemented*

Science.gov (United States)

Nagy, Krisztina; Pilbat, Ana-Maria; Groma, Géza; Szalontai, Balázs; Cuisinier, Frédéric J. G.

2010-01-01

The possible mechanism of casein aggregation and micelle buildup was studied in a new approach by letting α-casein adsorb from low concentration (0.1 mg·ml−1) solutions onto the charged surfaces of polyelectrolyte films. It was found that α-casein could adsorb onto both positively and negatively charged surfaces. However, only when its negative phosphoseryl clusters remained free, i.e. when it adsorbed onto a negative surface, could calcium phosphate (CaP) nanoclusters bind to the casein molecules. Once the CaP clusters were in place, step-by-step building of multilayered casein architectures became possible. The presence of CaP was essential; neither Ca2+ nor phosphate could alone facilitate casein aggregation. Thus, it seems that CaP is the organizing motive in the casein micelle formation. Atomic force microscopy revealed that even a single adsorbed casein layer was composed of very small (in the range of tens of nanometers) spherical forms. The stiffness of the adsorbed casein layer largely increased in the presence of CaP. On this basis, we can imagine that casein micelles emerge according to the following scheme. The amphipathic casein monomers aggregate into oligomers via hydrophobic interactions even in the absence of CaP. Full scale, CaP-carrying micelles could materialize by interlocking these casein oligomers with CaP nanoclusters. Such a mechanism would not contradict former experimental results and could offer a synthesis between the submicelle and the block copolymer models of casein micelles. PMID:20921229

Specific binding-adsorbent assay method and test means

International Nuclear Information System (INIS)

1981-01-01

A description is given of an improved specific binding assay method and test means employing a nonspecific adsorbent for the substance to be determined, particularly hepatitis B surface (HBsub(s)) antigen, in its free state or additionally in the form of its immune complex. The invention is illustrated by 1) the radioimmunoadsorbent assay for HBsub(s) antigen, 2) the radioimmunoadsorbent assay for HBsub(s) antigen in the form of immune complex with antibody, 3) a study of adsorption characteristics of various anion exchange materials for HBsub(s) antigen, 4) the use of hydrophobic adsorbents in a radioimmunoadsorbent assay for HBsub(s) antigen and 5) the radioimmunoadsorbent assay for antibody to HBsub(s) antigen. The advantages of the present method for detecting HBsub(s) antigen compared to previous methods include the manufacturing advantages of eliminating the need for insolubilised anti-HBsub(s) and the advantages of a single incubation step, fewer manipulations, storability of adsorbent materials, increased sensitivity and versatility of detecting HBsub(s) antigen in the form of its immune complex if desired. (U.K.)

Production of adsorbent from palm shell for radioactive iodine scrubbing process

International Nuclear Information System (INIS)

Mohamad Azman Che Mat Isa; Ku Halim Ku Hamid; Muhd Noor Muhd Yunus; Mohamad Puad Abu; Abdul Halim Badaruddin; Mohammad Nizammudin Abd Aziz; Muhd Ridwan Abdul Rahim

2010-01-01

The biggest biomass source in Malaysia comes from oil palm industry. According to the statistic of year 2004, Malaysia produced 40 million tones per year of biomass which 30 million tones of biomass originated from the oil palm industries. Therefore, the biomass waste such as palm kernel shell can be used to produce granular adsorbent for radioactive materials. For that reason, a newly system, called Rocking Kiln - Fluidized Bed (RK - FB) was developed to utilize large amount of the biomass to produce high value added product. Charcoal or chemically produced activated carbon could be produced by using the kiln. Washing process was introduced to remove particles, minerals and volatile matters from charcoal produced and then would create more surface area in the adsorbent by creating more active sites. In this research, the adsorbent produced was used to scrub iodine 131. In nuclear power reactor, iodine isotope 131 is produced during nuclear fission, and this elementary radioactive iodine may pollute exhaust air streams that could cause thyroid cancer. For removal of radioactive iodine, normally a potassium iodide - impregnated activated carbon (KI - AC) is used. Thus, a process will be developed to produce KI - AC and this product will be used to calculate the efficiency to remove the radioactive iodine 131.The results obtain show that adsorbent produced has a high potential to be used in radioactive adsorbing and likely more economics. This paper will elaborate further the experimental set-up of in Kiln - Fluidized Bed (RK - FB), adsorbent quality and radioactive scrubbing process. (author)

Screening of natural adsorbents for removal of radio-contaminants from aqueous effluents

International Nuclear Information System (INIS)

Thorat, Vidya; Katarni, V.G.; Kaushik, C.P.; Kaushik, Chander P.; Sharma, J.K.

2010-01-01

The present paper is a summary of studies carried out to examine the uptake potential of some of the bio/natural adsorbents for removal of radiocontaminants from aqueous effluents. Three different bio/natural materials namely coconut coir pith, sugarcane bagasse and saw dust were selected as adsorbents. Preliminary characterisations of the above adsorbents were carried out and percentage of removal of 239 Pu and 241 Am from aqueous solutions were checked using batch equilibration method. (author)

Effect of adsorbents and chemical treatments on the removal of strontium from aqueous solutions

International Nuclear Information System (INIS)

Ahmadpour, A.; Zabihi, M.; Tahmasbi, M.; Bastami, T. Rohani

2010-01-01

In the present investigation, three different solid wastes namely almond green hull, eggplant hull, and moss were initially treated and used as adsorbents for the adsorption of strontium ion from aqueous solutions. Adsorbent types and chemical treatments are proved to have effective roles on the adsorption of Sr(II) ion. Among the three adsorbents, almond green hull demonstrated strong affinity toward strontium ion in different solutions. The effectiveness of this new adsorbent was studied in batch adsorption mode under a variety of experimental conditions such as: different chemical treatments, various amounts of adsorbent, and initial metal-ion concentration. The optimum doses of adsorbent for the maximum Sr(II) adsorption were found to be 0.2 and 0.3 g for 45 and 102 mg L -1 solutions, respectively. High Sr(II) adsorption efficiencies were achieved only in the first 3 min of adsorbent's contact time. The kinetics of Sr(II) adsorption on almond green hull was also examined and it was observed that it follows the pseudo second-order behavior. Both Langmuir and Freundlich models well predicted the experimental adsorption isotherm data. The maximum adsorption capacity on almond green hull was found to be 116.3 mg g -1 . The present study also confirmed that these low cost agriculture byproducts could be used as efficient adsorbents for the removal of strontium from wastewater streams.

Adsorption of water and butanol in silicalite-1 film studied with in situ attenuated total reflectance-Fourier transform infrared spectroscopy.

Science.gov (United States)

Farzaneh, Amirfarrokh; Zhou, Ming; Potapova, Elisaveta; Bacsik, Zoltán; Ohlin, Lindsay; Holmgren, Allan; Hedlund, Jonas; Grahn, Mattias

2015-05-05

Biobutanol produced by, e.g., acetone-butanol-ethanol (ABE) fermentation is a promising alternative to petroleum-based chemicals as, e.g., solvent and fuel. Recovery of butanol from dilute fermentation broths by hydrophobic membranes and adsorbents has been identified as a promising route. In this work, the adsorption of water and butanol vapor in a silicalite-1 film was studied using in situ attenuated total reflectance-Fourier transform infrared (ATR-FTIR) spectroscopy to better understand the adsorption properties of silicalite-1 membranes and adsorbents. Single-component adsorption isotherms were determined in the temperature range of 35-120 °C, and the Langmuir model was successfully fitted to the experimental data. The adsorption of butanol is very favorable compared to that of water. When the silicalite-1 film was exposed to a butanol/water vapor mixture with 15 mol % butanol (which is the vapor composition of an aqueous solution containing 2 wt % butanol, a typical concentration in an ABE fermentation broth, i.e., the composition of the gas obtained from gas stripping of an ABE broth) at 35 °C, the adsorption selectivity toward butanol was as high as 107. These results confirm that silicalite-1 quite selectively adsorbs hydrocarbons from vapor mixtures. To the best of our knowledge, this is the first comprehensive study on the adsorption of water and butanol in silicalite-1 from vapor phase.

The synthesis of corncobs (zea mays) active charcoal and water hyacinth (eichornia crassipes) adsorbent to adsorb Pb(II) with it’s analysis using solid-phase spectrophotometry (sps)

Science.gov (United States)

Saputro, S.; Masykuri, M.; Mahardiani, L.; Kurniastuti, D.

2018-03-01

This research aim to examine the effect of the combination between corncobs and water hyacinth to adsorb lead (II), the most effective combination have determined by compared the ratio of corncobs adsorbent and water hyacinth to the increasing adsorption of the Pb(II), prove the effectiveness of the solid-phase spectrophotometry (sps) to determine the levels of Pb(II) as the result of the corncobs active charcoal adsorption and water hyacinth in the level of µg/L. The research method used is experimental method. The data collecting technique is carried out by several stages, which are carbonization using muffle furnace at a temperature of 350°C for 1.5 hours, activation of the corncobs charcoal and water hyacinth using HCl 1M and HCl 5M activator, contacting the adsorbent of corncobs active charcoal and water hyacinth with liquid waste simulation of Pb(II) using variation of corncobns and water hyacinth, 1:0; 0:1; 1:1; 2:1; 1:2, analysis of Pb(II) using an sps, characterization of corncobs active charcoal adsorbent and water hyacinth using FTIR. Research results show that the combined effect of activated charcoal corncobs and water hyacinth can increase the ability of the adsorbent to absorb Pb(II), the optimum adsorbent mass ratio of 1:1 with the absorption level of 90.33%, SPS is an effective method to analyze the decreasing level of Pb(II) as the adsorbtion result of the corncobs active charcoal and water hyacinth in the level of µg/L, with the limit of detection (LOD) of 0.06 µg/L.

Effect of plasma energy on enhancing biocompatibility and hemocompatibility of diamond-like carbon film with various titanium concentrations

International Nuclear Information System (INIS)

Cheng, H.-C.; Chiou, S.-Y.; Liu, C.-M.; Lin, M.-H.; Chen, C.-C.; Ou, K.-L.

2009-01-01

This investigation develops and explores a new method for depositing a DLC film containing titanium. A bioactive DLC film with titanium dopant (Ti-DLC) was formed by co-sputtering. To determine the properties of DLC films with and without Ti, the specimens were evaluated by material analyses and cell culture. The multilayered nanocrystal TiC was embedded in the amorphous DLC matrix. Microtwins were present between TiC and Ti-DLC. They relaxed residual stress and improved the adhesion of Ti-DLC to the TiC film. The Ti-DLC film proliferates more effectively than Ti or DLC, revealing that the biocompatibility of Ti-DLC clearly exceeds that of DLC, Ti and TiC films. The Ti-DLC film proliferates more effectively than Ti, TiC or DLC film, revealing that the biocompatibility of Ti-DLC clearly exceeds that of DLC and Ti film. In addition, the higher deposited plasma energies were, more densification the films were. It is believed that high plasma energy enhanced the film densification, and then improves surface contact area of adsorbing proteins. It is believed that enhancing cell attachment and subsequently inducing cell proliferation and cell differentiation is related with plasma energy during deposition of Ti-DLC films.

Effect of film thickness on morphological evolution in dewetting and crystallization of polystyrene/poly(ε-caprolactone) blend films.

Science.gov (United States)

Ma, Meng; He, Zhoukun; Yang, Jinghui; Chen, Feng; Wang, Ke; Zhang, Qin; Deng, Hua; Fu, Qiang

2011-11-01

In this Article, the morphological evolution in the blend thin film of polystyrene (PS)/poly(ε-caprolactone) (PCL) was investigated via mainly AFM. It was found that an enriched two-layer structure with PS at the upper layer and PCL at the bottom layer was formed during spinning coating. By changing the solution concentration, different kinds of crystal morphologies, such as finger-like, dendritic, and spherulitic-like, could be obtained at the bottom PCL layer. These different initial states led to the morphological evolution processes to be quite different from each other, so the phase separation, dewetting, and crystalline morphology of PS/PCL blend films as a function of time were studied. It was interesting to find that the morphological evolution of PS at the upper layer was largely dependent on the film thickness. For the ultrathin (15 nm) blend film, a liquid-solid/liquid-liquid dewetting-wetting process was observed, forming ribbons that rupture into discrete circular PS islands on voronoi finger-like PCL crystal. For the thick (30 nm) blend film, the liquid-liquid dewetting of the upper PS layer from the underlying adsorbed PCL layer was found, forming interconnected rim structures that rupture into discrete circular PS islands embedded in the single lamellar PCL dendritic crystal due to Rayleigh instability. For the thicker (60 nm) blend film, a two-step liquid-liquid dewetting process with regular holes decorated with dendritic PCL crystal at early annealing stage and small holes decorated with spherulite-like PCL crystal among the early dewetting holes at later annealing stage was observed. The mechanism of this unusual morphological evolution process was discussed on the basis of the entropy effect and annealing-induced phase separation.

Residence time determination for adsorbent beds of different configurations

Energy Technology Data Exchange (ETDEWEB)

Otermat, J.E.; Wikoff, W.O.; Kovach, J.L.

1995-02-01

The residence time calculations of ASME AG-1 Code, Section FC, currently specify a screen surface area method, that is technically incorrect. Test data has been obtained on Type II adsorber trays of different configurations to establish residence time in the adsorber trays. These data indicate that the air volume/carbon volume ratio or the average screen area are more appropriate for the calculation of the residence time calculation than the currently used, smallest screen area basis.

X-ray photoelectron spectroscopy study and thermoelectric properties of Al-doped ZnO thin films

International Nuclear Information System (INIS)

Li Li; Fang Liang; Zhou Xianju; Liu Ziyi; Zhao Liang; Jiang Sha

2009-01-01

In this paper, high quality Al-doped ZnO (AZO) thin films were prepared by direct current (DC) reactive magnetron sputtering using a Zn target (99.99%) containing Al of 1.5 wt.%. The films obtained were characterized by X-ray photoelectron spectroscopy (XPS) and thermoelectric measurements. The XPS results reveal that Zn and Al exist only in oxidized state, while there are dominant crystal lattice and rare adsorbed oxygen for O in the annealed AZO thin films. The studies of thermoelectric property show a striking thermoelectric effect in the AZO thin films. On the one hand, the thermoelectromotive and magnetothermoelectromotive forces increase linearly with increasing temperature difference (ΔT). On the other hand, the thermoelectric power (TEP) decreases with the electrical resistance of the sample. But the TEP increases with the increase of temperature below 300 K, and it nearly does not change around room temperature. The experimental results also demonstrate that the annealing treatment increases TEP, while the external magnetic field degrades TEP.

Citrus paradisi: An Effective bio-adsorbent for Arsenic (V Remediation

Directory of Open Access Journals (Sweden)

Mazhar I. Khaskheli

2014-06-01

Full Text Available In the present study As (V was removed by citrus paradisi (grape fruit peel. Kinetics of the adsorption reaction was analyzed by the Pseudo second order and Morris-weber equations. Freundlich and Langmuir isotherm models were utilized for understanding of the relationship between the arsenic ions and citrus paradisi peel adsorbent. The maximum measured uptake capacity of citrus paradisi was 37.76 mg.g-1 at pH 4. FT-IR characterization of unloaded and As (V loaded citrus paradisi peel adsorbent showed the participation of carbonyl (CO and hydroxyl (OH groups in adsorption process. The proposed citrus paradisi peel adsorbent with optimized parameters was used for the removal of arsenic from arsenic contaminated real water samples.

Metal Adsorbent Prepared from Poly(Methyl Acrylate)-Grafted Cassava Starch via Gamma Irradiation

Energy Technology Data Exchange (ETDEWEB)

Suwanmala, P; Hemvichian, K; Srinuttrakul, W [Nuclear Research and Development Group, Thailand Institute of Nuclear Technology, Bangkok (Thailand)

2012-09-15

Metal adsorbent containing hydroxamic acid groups was successfully synthesized by radiation-induced graft copolymerization of methyl acrylate (MA) onto cassava starch. The optimum conditions for grafting were studied in terms of % degree of grafting (Dg). Conversion of the ester groups present in poly(methyl acrylate)-grafted-cassava starch copolymer into hydroxamic acid was carried out by treatment with hydroxylamine (HA) in the presence of alkaline solution. The maximum percentage conversion of the ester groups of the grafted copolymer, %Dg = 191 (7.63 mmol/g of MA), into the hydroxamic groups was 70% (5.35 mmol/g of MA) at the optimum conditions: in a mixture solution of 20% HA (w/v) and methanol solution (methanol:H{sub 2}O = 5:1) 300 mL, pH 13, reaction time 2 h, and 20 g of grafted copolymer. The adsorbent was characterized by FTIR, TGA, and DSC. The presence of electron donating groups in adsorbent containing hydroxamic acid groups gives the ability to form polycomplexes with metal ions. The ability of the adsorbent to adsorb various metals was investigated in order to evaluate the possibility of its use in metal adsorption. The adsorbent exhibited a remarkable % adsorption for Cd{sup 2+}, Al{sup 3+}, UO{sub 2} {sup 2+}, V{sup 5+} and Pb{sup 2+} at pH 3, 4, 5, 4, and 3, respectively. The adsorbent of 191%Dg had total adsorption capacities of 2.6, 1.46, 1.36, 1.15, and 1.6 mmol/g adsorbent for Cd{sup 2+}, Al{sup 3+}, UO{sub 2} {sup 2+}, V{sup 5+} and Pb{sup 2+}, respectively, in the batch mode adsorption. (author)

High performance of a unique mesoporous polystyrene-based adsorbent for blood purification.

Science.gov (United States)

Chen, Jian; Han, Wenyan; Chen, Jie; Zong, Wenhui; Wang, Weichao; Wang, Yue; Cheng, Guanghui; Li, Chunran; Ou, Lailiang; Yu, Yaoting

2017-02-01

A multi-functional polystyrene based adsorbent (NKU-9) with a unique mesoporous and a high surface area was prepared by suspension polymerization for removal of therapeutic toxins in blood purification. The adsorbent produced had an almost equal amount of mesopore distribution in the range from 2 to 50 nm. The adsorption of serum toxins with different molecular weights were examined by in vitro adsorption assays and compared with some clinical currently used adsorbents such as HA-330, Cytosorb and BL-300 which are produced by China, America and Japan, respectively. Test results indicated that the adsorption rate for pentobarbital by NKU-9 was 81.24% which is nearly as high as HA-330 (81.44%). The latter adsorbent is currently used for acute detoxification treatment in China. To reach adsorption equilibrium, NKU-9 was faster than HA-330, which implies short treatment time. For the removal of middle molecular toxins such as β2-microglobulin (98.88%), NKU-9 performed better adsorptive selectivity than Cytosorb (92.80%). In addition, NKU-9 showed high performance for the removal of albumin-bound toxins (e.g., bilirubin), and its adsorption rate for total bilirubin (80.79%) in plasma was 8.4% higher than that of anion exchange resin BL-300 which is currently used to eliminate bilirubin in clinic. Therefore, our results indicate that the newly developed adsorbent with a wide distribution and almost equal amount of mesopores is a multifunctional adsorbent for high efficient removal of serum toxins with different molecular weights which might be an excellent blood purification adsorbent especially to treat diseases that conventional medical methods are low or not efficient.

Thiol-functionalized polysilsesquioxane as efficient adsorbent for adsorption of Hg(II) and Mn(II) from aqueous solution

International Nuclear Information System (INIS)

Niu, Yuzhong; Qu, Rongjun; Liu, Xiguang; Mu, Lei; Bu, Baihui; Sun, Yuting; Chen, Hou; Meng, Yangfeng; Meng, Lina; Cheng, Lin

2014-01-01

Highlights: • PMPSQ was promising adsorbent for the removal of Hg(II) and Mn(II). • The adsorption kinetics followed the pseudo-second-order model. • The adsorption isotherms can be described by the monolayer Langmuir model. • The adsorption was controlled by film diffusion and chemical ion-exchange mechanism. - Abstract: Thiol-functionalized polysilsesquioxane was synthesized and used for the adsorption of Hg(II) and Mn(II) from aqueous solution. Results showed that the optimal pH was about 6 and 5 for Hg(II) and Mn(II), respectively. Adsorption kinetics showed that the adsorption equilibriums were established within 100 min and followed pseudo-second-order model. Adsorption isotherms revealed that the adsorption capacities increased with the increasing of temperature. The adsorption was found to be well described by the monolayer Langmuir isotherm model and took place by chemical ion-exchange mechanism. The thermodynamic properties indicated the adsorption processes were spontaneous and endothermic nature. Selectively adsorption showed that PMPSQ can selectively adsorb Hg(II) from binary ion systems in the presence of the coexistent ions Mn(II), Cu(II), Pb(II), Co(II), and Ni(II). Based on the results, it is concluded that PMPSQ had comparable high adsorption efficiency and could be potentially used for the removal of Hg(II) and Mn(II) from aqueous solution

Hafnium carbide formation in oxygen deficient hafnium oxide thin films

Energy Technology Data Exchange (ETDEWEB)

Rodenbücher, C. [Forschungszentrum Jülich GmbH, Peter Grünberg Institute (PGI-7), JARA-FIT, 52425 Jülich (Germany); Hildebrandt, E.; Sharath, S. U.; Kurian, J.; Komissinskiy, P.; Alff, L. [Technische Universität Darmstadt, Institute of Materials Science, 64287 Darmstadt (Germany); Szot, K. [Forschungszentrum Jülich GmbH, Peter Grünberg Institute (PGI-7), JARA-FIT, 52425 Jülich (Germany); University of Silesia, A. Chełkowski Institute of Physics, 40-007 Katowice (Poland); Breuer, U. [Forschungszentrum Jülich GmbH, Central Institute for Engineering, Electronics and Analytics (ZEA-3), 52425 Jülich (Germany); Waser, R. [Forschungszentrum Jülich GmbH, Peter Grünberg Institute (PGI-7), JARA-FIT, 52425 Jülich (Germany); RWTH Aachen, Institute of Electronic Materials (IWE 2), 52056 Aachen (Germany)

2016-06-20

On highly oxygen deficient thin films of hafnium oxide (hafnia, HfO{sub 2−x}) contaminated with adsorbates of carbon oxides, the formation of hafnium carbide (HfC{sub x}) at the surface during vacuum annealing at temperatures as low as 600 °C is reported. Using X-ray photoelectron spectroscopy the evolution of the HfC{sub x} surface layer related to a transformation from insulating into metallic state is monitored in situ. In contrast, for fully stoichiometric HfO{sub 2} thin films prepared and measured under identical conditions, the formation of HfC{sub x} was not detectable suggesting that the enhanced adsorption of carbon oxides on oxygen deficient films provides a carbon source for the carbide formation. This shows that a high concentration of oxygen vacancies in carbon contaminated hafnia lowers considerably the formation energy of hafnium carbide. Thus, the presence of a sufficient amount of residual carbon in resistive random access memory devices might lead to a similar carbide formation within the conducting filaments due to Joule heating.

Adsorption of Cr(VI) using silica-based adsorbent prepared by radiation-induced grafting

International Nuclear Information System (INIS)

Qiu Jingyi; Wang Ziyue; Li Huibo; Xu Ling; Peng Jing; Zhai Maolin; Yang Chao; Li Jiuqiang; Wei Genshuan

2009-01-01

Silica-based adsorbent was prepared by radiation-induced grafting of dimethylaminoethyl methacrylate (DMAEMA) onto the silanized silica followed by a protonation process. The FTIR spectra and XPS analysis proved that DMAEMA was grafted successfully onto the silica surface. The resultant adsorbent manifested a high ion exchange capacity (IEC) of ca. 1.30 mmol/g and the Cr(VI) adsorption behavior of the adsorbent was further investigated, revealing the recovery of Cr(VI) increased with the adsorbent feed and the equilibrium adsorption could be achieved within 40 min. The adsorption capacity, strongly depended on the pH of the solution, reached a maximum Cr(VI) uptake (ca. 68 mg/g) as the pH was in the range of 2.5-5.0. Furthermore, even in strong acidic (4.0 mol/L HNO 3 ) or alkaline media (pH 11.0), the adsorbent had a sound Cr(VI) uptake capacity (ca. 22 and 30 mg/g, respectively), and the adsorption followed Langmuir mode. The results indicated that this adsorbent, prepared via a convenient approach, is applicable for removing heavy-metal-ion pollutants (e.g. Cr(VI)) from waste waters.

New adsorbents from oil shales. Preparation, characterization and U, Th isotope adsorption tests

International Nuclear Information System (INIS)

Khouya, E.; Andres, Y.; Naslain, R.; Pailler, R.; Nourredine, A.

2004-01-01

New activated adsorbents for radionuclides have been produced from Moroccan oil shales by pyrolysis of the natural material at 550 deg C flowed by a KMnO 4 activation. The texture and composition of the native rock and the adsorbents were studied before their use in tests for adsorption of radionuclides from standard solutions prepared from uranylnitrate and thorium nitrate in equilibrium with their daughters. The distribution coefficients between solutions containing U, Th and Ra and the adsorbents were evaluated by means of specific activities, measured by γ-ray spectrometry. The adsorbents were observed to eliminate U, Th, Ra, Ac and Tl from aqueous solutions. (author)

Extensibility effect of poly(3-hexylthiophene) on the glucose sensing performance of mixed poly(3-hexylthiophene)/octadecylamine/glucose oxidase Langmuir-Blodgett films.

Science.gov (United States)

Wang, Ke-Hsuan; Hsu, Wen-Ping; Chen, Liang-Huei; Lin, Wei-Don; Lee, Yuh-Lang

2017-07-01

Poly(3-hexylthiophene) (P3HT) is utilized as a material to enhance the glucose sensing performance of glucose oxidase (GOx) Langmuir-Blodgett (LB) films. To enhance the extensibility and homogeneity of the P3HT in the LB films, octadecylamine (ODA) is introduced. The characteristics of the mixed P3HT/ODA Langmuir monolayers are investigated first and then, utilized as template layers to adsorb GOx from the subphase, preparing P3HT/ODA/GOx Langmuir-Blodgett films for glucose sensing. The results show that P3HT molecules tend to aggregate at the air/liquid interface and, furthermore, the P3HT monolayer has a weak ability to adsorb GOx from the subphase. By using mixed P3HT/ODA monolayer, the presence of ODA not only inhibits the aggregation of P3HT, but also increases the adsorption ability of the monolayer to GOx. The extensibility of P3HT and the homogeneity of the P3HT/ODA monolayers are closely related to the concentration of P3HT/ODA stock solutions. On the glucose sensing experiments, the performance of the P3HT/ODA/GOx LB film is greatly improved due to the presence of P3HT and, furthermore, the sensibility increases with increasing extensibility of P3HT molecules. The best sensitivity achieved for the P3HT/ODA/GOx film is 5.4μAmM -1 cm -2 which is over two times the value obtained by the ODA/GOx film (2.3μAmM -1 cm -2 ). Copyright © 2017 Elsevier B.V. All rights reserved.

Tribology of carbide derived carbon films synthesized on tungsten carbide

Science.gov (United States)

Tlustochowicz, Marcin

Tribologically advantageous films of carbide derived carbon (CDC) have been successfully synthesized on binderless tungsten carbide manufactured using the plasma pressure compaction (P2CRTM) technology. In order to produce the CDC films, tungsten carbide samples were reacted with chlorine containing gas mixtures at temperatures ranging from 800°C to 1000°C in a sealed tube furnace. Some of the treated samples were later dechlorinated by an 800°C hydrogenation treatment. Detailed mechanical and structural characterizations of the CDC films and sliding contact surfaces were done using a series of analytical techniques and their results were correlated with the friction and wear behavior of the CDC films in various tribosystems, including CDC-steel, CDC-WC, CDC-Si3N4 and CDC-CDC. Optimum synthesis and treatment conditions were determined for use in two specific environments: moderately humid air and dry nitrogen. It was found that CDC films first synthesized at 1000°C and then hydrogen post-treated at 800°C performed best in air with friction coefficient values as low as 0.11. However, for dry nitrogen applications, no dechlorination was necessary and both hydrogenated and as-synthesized CDC films exhibited friction coefficients of approximately 0.03. A model of tribological behavior of CDC has been proposed that takes into consideration the tribo-oxidation of counterface material, the capillary forces from adsorbed water vapor, the carbon-based tribofilm formation, and the lubrication effect of both chlorine and hydrogen.

Effect of divalent ions on the optical emission behavior of protein thin films

Energy Technology Data Exchange (ETDEWEB)

Bhowal, Ashim Chandra, E-mail: ashimbhowal111@gmail.com; Kundu, Sarathi [Physical Sciences Division, Institute of Advanced Study in Science and Technology, Vigyan Path, Paschim Boragaon, Garchuk, Guwahati, Assam 781035 (India)

2016-05-06

Photoluminescence behaviors of proteinthin film, bovine serum albumin (BSA) have been studied in the presence of three divalent ions (Mg{sup 2+}, Ca{sup 2+} and Ba{sup 2+}) at different temperatures using fluorescence spectroscopy. Film thickness and morphology have been studied using atomic force microscopy. Variation of different physicochemical parameters like temperature, solvent polarity, pH, ionic strength, substrate binding etc. can make conformational changes in the protein structure and hence influences the emission behavior.In thin film conformation of BSA, dynamic quenching behavior has beenidentified in the presence of all the three divalent ions at pH≈ 5.5. Depending upon the charge density of the divalent ions interaction with protein molecules modifies and as a result quenching efficiency varies. Also after heat treatment, conformation of the protein molecules changes and as a result the quenching efficiency enhances than that of the unheated films. Studies on such protein-ion interactions and conformational variation may explore various functions of protein when it will adsorb on soft surfaces like membranes, vesicles, etc.

Poorly crystalline hydroxyapatite: A novel adsorbent for enhanced fulvic acid removal from aqueous solution

Science.gov (United States)

Wei, Wei; Yang, Lei; Zhong, Wenhui; Cui, Jing; Wei, Zhenggui

2015-03-01

In this study, poorly crystalline hydroxyapatite (HAP) was developed as an efficient adsorbent for the removal of fulvic acid (FA) from aqueous solution. Surface functionality, crystallinity, and morphology of the synthetic adsorbent were studied by Fourier-transformation infrared (FT-IR) spectroscopy, powder X-ray diffraction (XRD) and transmission electron microscopy (TEM). The effects of various parameters such as crystallinity of adsorbent, contact time, adsorbent dosage, pH, initial adsorbate concentration, temperature, ionic strength and the presence of alkaline earth metal ions on FA adsorption were investigated. Results indicated that the nanosized HAP calcined at lower temperature was poorly crystalline (Xc = 0.23) and had better adsorption capacity for FA than those (Xc = 0.52, 0.86) calcined at higher temperature. FA removal was increased with increases of adsorbent dosage, temperature, ionic strength and the presence of alkali earth metal ions, but decreased as the pH increased. Kinetic studies showed that pseudo-second-order kinetic model better described the adsorption process. Equilibrium data were best described by Sips models, and the estimated maximum adsorption capacity of poorly crystalline HAP was 90.20 mg/g at 318 K, displaying higher efficiency for FA removal than previously reported adsorbents. FT-IR results revealed that FA adsorption over the adsorbent could be attributed to the surface complexation between the oxygen atom of functional groups of FA and calcium ions of HAP. Regeneration studies indicated that HAP could be recyclable for a long term. Findings of the present work highlight the potential for using poorly crystalline HAP nanoparticles as an effective and recyclable adsorbent for FA removal from aqueous solution.

Surface structure determinations of crystalline ionic thin films grown on transition metal single crystal surfaces by low energy electron diffraction

Energy Technology Data Exchange (ETDEWEB)

Roberts, Joel Glenn [Univ. of California, Berkeley, CA (United States)

2000-05-01

The surface structures of NaCl(100), LiF(100) and alpha-MgCl2(0001) adsorbed on various metal single crystals have been determined by low energy electron diffraction (LEED). Thin films of these salts were grown on metal substrates by exposing the heated metal surface to a molecular flux of salt emitted from a Knudsen cell. This method of investigating thin films of insulators (ionic salts) on a conducting substrate (metal) circumvents surface charging problems that plagued bulk studies, thereby allowing the use of electron-based techniques to characterize the surface.

Experimental Evaluation Use of Semifluidized Bed Adsorber for the Treatment of P-chlorophenol and O-cresol in Wastewater using Activated Carbon as Adsorbent

Directory of Open Access Journals (Sweden)

Saad Hanash Ammar

2015-12-01

Full Text Available In the present work the performance of semifluidized bed adsorber was evaluated for removal of phenolic compound from wastewater using commercial activated carbon as adsorbent. P-chlorophenol (4-Chlorophenol and o-cresol (2-methylphenol was selected as a phenolic compound for that purpose. The phenols percent removal, in term of breakthrough curves were studied as affected by hydrodynamics limitations which include minimum and maximum semifluidization velocities and packed bed formation in the column by varying various parameters such as inlet liquid superficial velocity (from Uminsf to 8Uminsf m/s, and retaining grid (sometimes referred to as adsorbent loading to initial static bed height ratio (from 3-4.5. Inlet phenols concentration (50-400 mg/l and initial pH of the liquid solutions feed (from 4 to 10 were also studied. The experimental semifluidized adsorber unit was designed and constructed in Chem. Eng. labs at Al-Nahrain University (consisted of a QVF glass tube 2.54 cm inside diameter, and 70cm length. The results showed that the initial percent removal of phenolic compounds (P-chlorophenol and o-cresol decrease with increasing the superficial liquid velocity while the time required reaching equilibrium state decreased. Also it slightly affected with the increase in the retaining grid height and the time required to reach the equilibrium value decreased.

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

International Nuclear Information System (INIS)

Shvoeva, O.P.; Kuchava, G.P.; Evtikova, G.A.; Belyaeva, V.K.; Myasoedova, G.V.; Marov, I.N.

1989-01-01

Equilibrium and kinetic characteristics of V 4+ sorption by POLYORGS XI-H adsorbent with benzimidazole groups (BIm) are investigated. Using ESR method it is stated that [VO 2+ ]:[BIm]1:2 complex, where VO 2+ is combined with nitrogen atoms of two imidazole groups, is formed in adsorbent phase. The highest distribution factor of 4.7x10 3 is attained at pH6

Stochastic Description of Activated Surface Diffusion with Interacting Adsorbates

Science.gov (United States)

Martínez-Casado, Ruth; Vega, José Luis; Sanz, Ángel S.; Miret-Artés, Salvador

Activated surface diffusion on metal surfaces is receiving much attention both experimentally and theoretically. One of the main theoretical problems in this field is to explain the line-shape broadening observed when the surface coverage is increased. Recently, we have proposed a fully stochastic model, the interacting single adsorbate (ISA) model, aimed at explaining and understanding this type of experiments, which essentially consists of considering the classical Langevin formulation with two types of noise forces: (i) a Gaussian white noise accounting for the substrate friction, and (ii) a shot noise simulating the interacting adsorbates at different coverages. No interaction potential between adsorbates is included because any trace of microscopic interaction seems to be wiped out in a Markovian regime. This model describes in a good approximation, and at a very low computational cost, the line-shape broadening observed experimentally. Furthermore, its mathematical simplicity also allows to derive some analytical expressions which are of much help in the interpretation of the physics underlying surface diffusion processes.

Numerical study of friction of flake and adsorbed monolayer on atomically clean substrate

International Nuclear Information System (INIS)

Matsukawa, Hiroshi; Haraguchi, Kazuhiro; Ozaki, Shinsuke

2007-01-01

Frictional behaviors of flake and adsorbed monolayer on substrate can be observed by Frictional force microscope and Quartz crystal microbalance experiments and are typical problems in nano-friction. Computer simulations had been played important roles in understanding those behaviors, but in most of them the driving direction coincides with one of the crystal axes of the substrate. Here we report our numerical results of direction dependence of friction of flake and adsorbed monolayer. We found a new kind of dynamical phase transition in which flake and adsorbed monlayer change their structure relative to the substrate and make incommensurae structure to reduce kinetic frictional force after certain transition time. When the driving velocity is decreased the transition time tends to diverge at certain critical velocity for the flake. For the adsorbed monlayer the transition time tends to diverge at certain critical magnitudes of the external force or the interaction strength between adsorbates when they are decreased

Flexible free-standing TiO2/graphene/PVdF films as anode materials for lithium-ion batteries

International Nuclear Information System (INIS)

Ren, H.M.; Ding, Y.H.; Chang, F.H.; He, X.; Feng, J.Q.; Wang, C.F.; Jiang, Y.; Zhang, P.

2012-01-01

Highlights: ► Flexible TiO 2 /graphene electrode was prepared by a solvent evaporation technique. ► PVdF was used as substance to support the TiO 2 /graphene active materials. ► The flexible films can be employed as anode materials for Li-ion battery. - Abstract: Graphene composites were prepared by hydrothermal method using titanium dioxide (TiO 2 ) adsorbed graphene oxide (GO) sheets as precursors. Free-standing hybrid films for lithium-ion batteries were prepared by adding TiO 2 /graphene composites to the polyvinylidene fluoride (PVdF)/N-methyl-2-pyrrolidone (NMP) solution, followed by a solvent evaporation technique. These films were characterized by atomic force microscopy (AFM), X-ray diffraction (XRD), scanning electron microscopy (SEM) and various electrochemical techniques. Flexible films show an excellent cycling performance, which was attributed to the interconnected graphene conducting network, which depressed the increasing of electric resistance during the cycling.

The effect of water on the electrochromic properties of WO{sub 3} films prepared by vacuum and chemical methods

Energy Technology Data Exchange (ETDEWEB)

Leftheriotis, G.; Papaefthimiou, S.; Yianoulis, P. [Department of Physics, University of Patras, Patras 26500 (Greece)

2004-06-01

We present a comparative study on the effect of absorbed water on the properties of tungsten oxide films prepared by two different methods (e-gun evaporation, and an aqueous sol-gel technique). Scanning electron microscopy, Fourier transform infrared spectroscopy and electrochemical techniques have been used to assess the film properties. It has been found that the preparation method of the films greatly affects their water content and thus, electron gun evaporated films have less water incorporated into their structure than their sol-gel counterparts. The former are closely packed and transparent with most of their water content adsorbed on their surface, while the latter have a porous structure, being opaque, highly hydroxylated and hydrated to a lesser extent. Both types of films exhibit reversible electrochromism, with the evaporated films being stable up to 5000 coloration-bleaching cycles and the sol-gel ones gradually degrading after 1000 cycles. Irreversible Li{sup +} trapping related to the presence of water and hydroxyl radicals has been envisaged as the cause of the inferior cycling stability of the sol-gel films.

Quantitative relationship between adsorbed amount of solute and solvent composition

International Nuclear Information System (INIS)

Wang Yan; Geng Xindu; Zebolsky, Don M.

2003-01-01

A new adsorption isotherm that relates the amount of solute adsorbed to the solvent concentration is proposed. The new equation is derived from Geng and Shi's stoichiometric displacement model for adsorption (SDM-A). The obtained equation may be simplified to an expression containing two parameters. The equation with two parameters, valid for low concentrations of solute, is a logarithmically linear relationship. The intercept contains a thermodynamic equilibrium constant of the solute displacing solvent from the adsorbent. The slope is the negative value of the stoichiometric displacement parameter (Z), the average total number of solvent molecules displaced from an active site on the adsorbent and from the solute. Tests with a homologous series of aromatic alcohols by frontal analysis in reversed phase liquid chromatography demonstrate that experimental results fit the equation well

Developing strategies for the regeneration of polyethylenimine based CO{sub 2} adsorbents

Energy Technology Data Exchange (ETDEWEB)

Trevor C. Drage; Karl M. Smith; Ana Arenillas; Colin E. Snape [University of Nottingham, Nottingham (United Kingdom). Nottingham Fuel and Energy Centre, School of Chemical, Environmental and Mining Engineering

2007-07-01

Adsorption is considered to be one of the more promising technologies for capturing CO{sub 2} from flue gases. The efficient adsorption of CO{sub 2} at low partial pressures, associated with post-combustion capture, require chemical type adsorbents containing basic amine functional groups. It has been demonstrated that amine polymers, for example polyethylenimine (PEI), immobilised on various porous substrates, silica, zeolites and fly ash, are effective adsorbents for CO{sub 2}. When considering the use of adsorption for large scale CO{sub 2} capture, the ease of regeneration and the lifetime of the adsorbents are critical factors in determining their efficiency, cost and therefore feasibility for use. In this paper two approaches, thermal swing adsorption (TSA) cycles over a range of temperatures and time in an atmosphere of CO{sub 2} and thermally assisted pressure swing desorption, are explored for the regeneration of the PEI based adsorbents. The reactions occurring during the TSA regeneration of PEI based adsorbents in an atmosphere of CO{sub 2}, especially the formation of a thermostable complex between PEI and CO{sub 2} above 130{sup o}C are described. Identification of the complex by FTIR, XPS and 13C NMR and its attempted regeneration will be described. Overall, the results from this research have implications for the selection of regeneration strategies of all amine based CO{sub 2} adsorbents. 5 refs., 1 figs., 1 tab.

EDTA-functionalized clinoptilolite nanoparticles as an effective adsorbent for Pb(II) removal.

Science.gov (United States)

Eshraghi, Farahnaz; Nezamzadeh-Ejhieh, Alireza

2018-03-08

An efficient Pb(II) adsorbent was prepared by the modification of clinoptilolite nanoparticles (CpN) with ethylenediaminetetraacetic acid (EDTA). Samples were characterized by XRD, FT-IR, SEM, BET, TG-DTG, CHNS analyzer, and energy dispersive analysis X-ray spectroscopy (EDX). The experiments were designed by response surface methodology (RSM) based on central composite design (CCD) that suggested a quadratic model to predict the conditions and the interactions between the variables including adsorbent dosage, removal time, C Pb , and its solution pH. Adequacy of the suggested quadratic model was judged by ANOVA. The maximum Pb(II) removal of 0.27 mmol Pb(II) /g ads was achieved in optimal run including adsorbent dosage 2 g L -1 , removal time 271 min, C Pb 22.51 mmol L -1 , and Pb(II) solution pH 5.88. In binary metal cation systems including 1000 mg L -1 with respect to both Pb(II) and interfering cations, good selectivity of CpN-EDTA adsorbent was observed towards Pb(II) among the tested cations except Fe(III). Adsorption isotherm of lead removal by the adsorbent was well modeled by Langmuir equation, indicating a monolayer sorption of Pb(II) onto the adsorbent. The pseudo-second-order rate equation, indicating chemical reaction rate limiting step for the process, well modeled the kinetic of the process. An exothermic and spontaneous process was confirmed by the negative ∆H and ∆G.

Studies on some influential factors of the zinc-activated carbon composite adsorbent on adsorptivity for uranium

International Nuclear Information System (INIS)

Miyai, Yoshitaka; Kitamura, Takao; Takagi, Norio; Katoh, Shunsaku; Miyazaki, Hidetoshi

1978-01-01

Factors, which influence the uranium adsorption of powdery composite adsorbent of basic zinc carbonate and activated carbon were studied. In the range studied, zinc content of the adsorbent was the most influential factor on the uranium adsorption, and the second influential factor was sea water volume and the third factor was adsorption period. Interactive effects were observed between zinc content and sea water volume, and between zinc content and adsorption period, and it was deduced that there existed the optimum value of sea water volume and adsorption period respectively for the zinc content of the adsorbent. Maximum uranium adsorption of adsorbent with 40% zinc content was observed at sea water volume of 15 liters and adsorption period of 25 hrs. As for temperature in the range of 15 - 35 0 C, the lower the temperature, the larger amount of adsorbed uranium was. The powdery adsorbent was made into granule, and its strength and its uranium adsorptivity were studied in relation to the granulating conditions. By use of PVA with degree of polymerization above 1,700 as binder, the granular adsorbent with the same strength as commercial granular activated carbon was obtained. PVA amount and its degree of polymerization gave only small effect on uranium adsorption of the adsorbent. Effect of granule size on the uranium adsorption rate in the range of 1 - 4 mm was that the uranium adsorption rate changed proportionally to surface area of assumed sphere. As a test for practical use, five times repetitions of adsorption and desorption were carried out on the same granular adsorbent. During the repetition the amount of adsorbed uranium rather increased, and desorption ratio of adsorbed uranium was constant at 91 - 93%. The weight loss of the adsorbent in a cycle of adsorption and desorption was about 3%. (author)

Application of chitin and zeolite adsorbents for treatment of low level radioactive liquid wastes

International Nuclear Information System (INIS)

Moattar, F.; Hayeripour, S.

2004-01-01

Two types of shrimp chitin derivatives and two types of Iranian natural zeolite derivates were studied for adsorption and treatment of low-level radioactive liquid waste. Chitin with lowers than 10% and chitosan with higher than 90% deacetylation factor were selected as neutral organic adsorbents. Natural clinoptilolite of Firuzkooh area and Na from derivates of it were selected as natural inorganic adsorbents. The static and dynamic ion exchange experimental results show that the ad adsorption efficiency depend on particle size, Ph, adsorbent type, deacetylation factor ( in chitin adsorbents) and cation type. The best Cs adsorption occurred in Na from clinoptilolite. Nevertheless chitin derivatives, particularly chitosan, are more efficient than zeolite adsorbents for removing of radionuclides such as 137 Cs, 54 Mn, 90 Sr and 60 Co. Adsorption performance was discussed and compared with each other

ε-Polylysine-based thermo-responsive adsorbents for immunoglobulin adsorption-desorption under mild conditions.

Science.gov (United States)

Maruyama, Masashi; Shibuya, Keisuke

2017-08-22

Thermo-responsive adsorbents for immunoglobulin G (IgG) employing ε-polylysine (EPL) as a polymer backbone were developed. The introduction of mercaptoethylpyridine (MEP) as an IgG-binding ligand and hydrophobization of side chains afforded thermo-responsive IgG adsorbents, whose thermo-responsive IgG desorption ratio was up to 88% (EPL/MEP derivative 3m). The changes in surface densities of active MEP groups, which are caused by thermal conformational changes of the adsorbents, play key roles for IgG desorption. Although a trade-off of IgG adsorption capacity and IgG desorption ratio was observed, the present study offers a novel molecular design for thermo-responsive adsorbents with high synthetic accessibility and potentially low toxicity.

Removal of radium from aqueous solutions using adsorbent produced from coconut coir pith

International Nuclear Information System (INIS)

Zalina Laili; Muhamat Omar; Mohd Zaidi Ibrahim; Esther Phillip; Mohd Abdul Wahab Yusof; Hassan, A.

2008-08-01

A study was conducted to evaluate the potential use of the coconut coir pith as an adsorbent for the removal of radium from aqueous solutions. Experiments to establish adsorptions as a function of pH and contact time were carried out. The results showed that radium adsorption are dependent upon pH and contact time of coconut coir pith with aqueous solutions. 70-80% of radium were adsorbed in the neutral to alkaline pH range. The amount of radium adsorbed also increased with contact time, reaching an optimum after 250 min. Thus, it can be concluded that the coconut coir pith has the potential to be used as an adsorbent in radium removal from aqueous solutions. (Author)

Synthesis and properties of a high-capacity iron oxide adsorbent for fluoride removal from drinking water

Science.gov (United States)

Zhang, Chang; Li, Yingzhen; Wang, Ting-Jie; Jiang, Yanping; Fok, Jason

2017-12-01

A novel iron oxide adsorbent with a high fluoride adsorption capacity was prepared by a facile wet-chemical precipitation method and ethanol treatment. The ethanol-treated adsorbent was amorphous and had a high specific surface area. The adsorption capacity of the treated adsorbent was much higher than that of untreated adsorbent. The Langmuir maximum adsorption capacity of the adsorbent prepared at a low final precipitation pH (≤9.0) and treated with ethanol reached 60.8 mg/g. A fast adsorption rate was obtained, and 80% of the adsorption equilibrium capacity was achieved within 2 min. The adsorbent had high fluoride-removal efficiency for water in a wide initial pH range of 3.5-10.3 and had a high affinity for fluoride in the presence of common co-anions. The ethanol treatment resulted in structure transformation of the adsorbent by inhibiting the crystallization of the nano-precipitates. The adsorption was confirmed to be ion exchange between fluoride ions and the hydroxyl groups on the adsorbent surface.

Surface potential-governed cellular osteogenic differentiation on ferroelectric polyvinylidene fluoride trifluoroethylene films.

Science.gov (United States)

Tang, Bolin; Zhang, Bo; Zhuang, Junjun; Wang, Qi; Dong, Lingqing; Cheng, Kui; Weng, Wenjian

2018-05-02

Surface potential of biomaterials can dramatically influence cellular osteogenic differentiation. In this work, a wide range of surface potential on ferroelectric polyvinylidene fluoride trifluoroethylene (P(VDF-TrFE)) films was designed to get insight into the interfacial interaction of cell-charged surface. The P(VDF-TrFE) films poled by contact electric poling at various electric fields obtained well stabilized surface potential, with wide range from -3 to 915 mV. The osteogenic differentiation level of cells cultured on the films was strongly dependent on surface potential and reached the optimum at 391 mV in this system. Binding specificity assay indicated that surface potential could effectively govern the binding state of the adsorbed fibronectin (FN) with integrin. Molecular dynamic (MD) simulation further revealed that surface potential brought a significant difference in the relative distance between RGD and synergy PHSRN sites of adsorbed FN, resulting in a distinct integrin-FN binding state. These results suggest that the full binding of integrin α5β1 with both RGD and PHSRN sites of FN possesses a strong ability to activate osteogenic signaling pathway. This work sheds light on the underlying mechanism of osteogenic differentiation behavior on charged material surfaces, and also provides a guidance for designing a reasonable charged surface to enhance osteogenic differentiation. The ferroelectric P(VDF-TrFE) films with steady and a wide range of surface potential were designed to understand underlying mechanism of cell-charged surface interaction. The results showed that the charged surface well favored upregulation of osteogenic differentiation of MC3T3-E1 cells, and more importantly, a highest level occurred on the film with a moderate surface potential. Experiments and molecular dynamics simulation demonstrated that the surface potential could govern fibronectin conformation and then the integrin-fibronectin binding. We propose that a full binding

Fast Removal of Polybrominated Diphenyl Ethers from Aqueous Solutions by Using Low-Cost Adsorbents

Directory of Open Access Journals (Sweden)

Renin Chang

2017-01-01

Full Text Available 4-Dibromodiphenyl ether (BDE-3 and 4,4′-dibromodiphenyl ether (BDE-15 are two of the major polybrominated diphenyl ethers used as flame-retardant additives in computer main boards and in fireproof building materials. In this study, we evaluated the potential of three low-cost adsorbents, black tea, green tea, and coconut palm leaf powders, to adsorb BDE-3 and BDE-15 from aqueous solutions. The results showed that pressure steam washing of the adsorbents increased their capacities to adsorb BDE-3 and BDE-15. The maximum adsorption capacities of pressure steam–washed black tea, green tea, and coconut palm leaf powders were 21.85 mg·L−1, 14.56 mg·L−1 and 22.47 mg·L−1, respectively. The results also showed that the adsorption equilibrium (qe was achieved at 4 min. Moreover, 97.8% of BDE-3 and 98.5% of BDE-15 could be removed by adsorbents pretreated with pressure steam washing. The kinetic data fitted well with a pseudo-second-order equation. The adsorption rate constants (k2 of all pressure steam–washed adsorbents ranged from 8.16 × 10−3 to 6.61 × 10−2 g·(mg·L−1−1·s−1, and the amount adsorbed at qe by all pressure steam–washed adsorbents ranged from 4.21 to 4.78 mg·L−1. Green alga Chlorella vulgaris was used as the test organism and the median effective concentration values of BDE-3 and BDE-15 were 7.24 and 3.88 mg·L−1, respectively. After BDE-3 and BDE-15 were removed from the solution, their biotoxicities markedly decreased. These findings indicate that these low-cost adsorbents can be used to remove BDE-3 and BDE-15 from aqueous solutions and wastewater.

Development of Silver-exchanged Adsorbents for the Removal of Fission Iodine from Alkaline Dissolution

Energy Technology Data Exchange (ETDEWEB)

Kim, Tae Woon; Lee, Seung Kon; Lee, Su Seung; Lee, Jun Sig [KAERI, Daejeon (Korea, Republic of); Kim, Sang Wook [Dongguk University, Gyeongju (Korea, Republic of)

2016-05-15

{sup 99} Mo is extracted from the filtrate solution through column-based multistep separation and purification process. In the process, removal of radio-impurities from the solution is essential to acquire high-quality fission {sup 99} Mo. Iodine is the main impurity having about 15% of total radioactivity among the whole fission products. Most of the iodine exists in the caustic dissolution as iodide form. In this study, silver-exchanged adsorbent is used to adsorb iodide from the solution. Adsorbed iodide can be recovered and recycled for radiopharmaceuticals. Compound is dried again. After heating ascorbic acid solution, solution is added to dried compound. Heat the mixture. After removing supernatant, the mixture is washed with hot distilled water and then cool distilled water in the order named. Finally, the mixture is heated and then recovering by using the sieve. In this study, silver-exchanged adsorbent is used to adsorb iodide from the solution. Adsorbed iodide can be recovered and recycled for radiopharmaceuticals. Silver-doped DAW-70 alumina by using silver mirror reaction is less impurities and simpler than method using ascorbic acid.

Adsorbates in a Box: Titration of Substrate Electronic States

Science.gov (United States)

Cheng, Zhihai; Wyrick, Jonathan; Luo, Miaomiao; Sun, Dezheng; Kim, Daeho; Zhu, Yeming; Lu, Wenhao; Kim, Kwangmoo; Einstein, T. L.; Bartels, Ludwig

2010-08-01

Nanoscale confinement of adsorbed CO molecules in an anthraquinone network on Cu(111) with a pore size of ≈4nm arranges the CO molecules in a shell structure that coincides with the distribution of substrate confined electronic states. Molecules occupy the states approximately in the sequence of rising electron energy. Despite the sixfold symmetry of the pore boundary itself, the adsorbate distribution adopts the threefold symmetry of the network-substrate system, highlighting the importance of the substrate even for such quasi-free-electron systems.

Oxide films at the nanoscale: new structures, new functions, and new materials.

Science.gov (United States)

Giordano, Livia; Pacchioni, Gianfranco

2011-11-15

We all make use of oxide ultrathin films, even if we are unaware of doing so. They are essential components of many common devices, such as mobile phones and laptops. The films in these ubiquitous electronics are composed of silicon dioxide, an unsurpassed material in the design of transistors. But oxide films at the nanoscale (typically just 10 nm or less in thickness) are integral to many other applications. In some cases, they form under normal reactive conditions and confer new properties to a material: one example is the corrosion protection of stainless steel, which is the result of a passive film. A new generation of devices for energy production and communications technology, such as ferroelectric ultrathin film capacitors, tunneling magnetoresistance sensors, solar energy materials, solid oxide fuel cells, and many others, are being specifically designed to exploit the unusual properties afforded by reduced oxide thickness. Oxide ultrathin films also have tremendous potential in chemistry, representing a rich new source of catalytic materials. About 20 years ago, researchers began to prepare model systems of truly heterogeneous catalysts based on thin oxide layers grown on single crystals of metal. Only recently, however, was it realized that these systems may behave quite differently from their corresponding bulk oxides. One of the phenomena uncovered is the occurrence of a spontaneous charge transfer from the metal support to an adsorbed species through the thin insulating layer (or vice versa). The importance of this property is clear: conceptually, the activation and bond breaking of adsorbed molecules begin with precisely the same process, electron transfer into an antibonding orbital. But electron transfer can also be harnessed to make a supported metal particle more chemically active, increase its adhesion energy, or change its shape. Most importantly, the basic principles underlying electron transfer and other phenomena (such as structural

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

International Nuclear Information System (INIS)

Hirotsu, Takahiro; Fujii, Ayako; Sakane, Kohji; Katoh, Shunsaku; Sugasaka, Kazuhiko

1984-01-01

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)

Influence of submonolayer films on the metal surface properties

International Nuclear Information System (INIS)

Bigun, G.I.

1979-01-01

Carried out is the calculation of concentration dependence of the work function, surface energy and binding energy of adsorption systems in the framework of ''jelly'' model. Electron density is approximated with parametric exponential family. Unknown parameters are found from the neutrality and continuity conditions using obtained relation of electrostatic potential values in the depth of the substrate and on the surface. Each of the systems Li-W(110), Na-W(110), K-W(111) and Cs-W(112) is compared with a certain value of the thickness of positive charge substituting adsorbate ion film. Quantitative agreement of the theory and experiment takes place

Characteristics of pellet-type adsorbents prepared from water treatment sludge and their effect on trimethylamine removal

Energy Technology Data Exchange (ETDEWEB)

Bae, Junghyun; Park, Nayoung; Kim, Goun; Lee, Choul Ho; Jeon, Jong-Ki [Kongju National University, Cheonan (Korea, Republic of); Park, Young-Kwon [University of Seoul, Seoul (Korea, Republic of)

2014-04-15

We optimized the preparation method of pellet-type adsorbents based on alum sludge with the aim of developing a high-performance material for the adsorption of gaseous trimethylamine. Effects of calcination temperature on physical and chemical properties of pellet-type adsorbents were investigated. The porous structure and surface characteristics of the adsorbents were studied using N{sub 2} adsorption and desorption isotherms, scanning electron microscope, X-ray diffraction, temperature-programmed desorption of ammonia, and infrared spectroscopy of adsorbed pyridine. The adsorbents obtained from the water treatment sludge are microporous materials with well-developed mesoporosity. The pellet-type adsorbent calcined at 500 .deg. C had the highest percentage of micropore volume and the smallest average pore diameter. The highest adsorption capacity in trimethylamine removal attained over the pellet-type adsorbent calcined at 500 .deg. C can be attributed to the highest number of acid sites as well as the well-developed microporosity.

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

Energy Technology Data Exchange (ETDEWEB)

Shvoeva, O P; Kuchava, G P; Evtikova, G A; Belyaeva, V K; Myasoedova, G V; Marov, I N [AN SSSR, Moscow (USSR). Inst. Geokhimii i Analiticheskoj Khimii

1989-04-01

Equilibrium and kinetic characteristics of V{sup 4+} sorption by POLYORGS XI-H adsorbent with benzimidazole groups (BIm) are investigated. Using ESR method it is stated that (VO{sup 2+}):(BIm)1:2 complex, where VO{sup 2+} is combined with nitrogen atoms of two imidazole groups, is formed in adsorbent phase. The highest distribution factor of 4.7x10{sup 3} is attained at pH6.

Synthesis of organic substances labelled with {sup 14}C and {sup 35}S; Syntheses de molecules organiques marquees par le carbone-14 et le soufre-35

Energy Technology Data Exchange (ETDEWEB)

Pichat, L [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

1958-07-01

After a brief history of the development of the Section des Molecules marquees of the Frenchmic Energy Commission, the author gives an outline of the synthesis of the following labelled compounds: benzene {sup 14}C-6; phenyl-p-fluorophenyl, thienyl-2 {beta} alanines {beta} {sup 14}C; noradrenaline {beta} {sup 14}C (arterenol {beta} {sup 14}C), dotriacontane {sup 14}C-16-17, aminoethane sulfinic acid (hypotaurine {sup 35}S). (author)Fren. [French] Apres un bref historique du developpement de la Section des Molecules marquees du Commissariat a l'Energie Atomique fran is, l'auteur donne un resume des syntheses des composes marques suivants: benzene {sup 14}C-6; phenyl-p-fluorophenyl, thienyl-2 {beta} alamines {beta} {sup 14}C; noradrenaline {beta} {sup 14}C (arterenol {beta} {sup 14}C), dotriacontane {sup 14}C-16-17, acide aminoethane sulfinique (hypotaurine {sup 35}S). (auteur)

Gas adsorption and capillary condensation in nanoporous alumina films

Energy Technology Data Exchange (ETDEWEB)

Casanova, Felix; Chiang, Casey E; Li, Chang-Peng; Roshchin, Igor V; Schuller, Ivan K [Physics Department, University of California-San Diego, La Jolla, CA 92093 (United States); Ruminski, Anne M; Sailor, Michael J [Department of Chemistry and Biochemistry, University of California-San Diego, La Jolla, CA 92093 (United States)], E-mail: casanova@physics.ucsd.edu

2008-08-06

Gas adsorption and capillary condensation of organic vapors are studied by optical interferometry, using anodized nanoporous alumina films with controlled geometry (cylindrical pores with diameters in the range of 10-60 nm). The optical response of the film is optimized with respect to the geometric parameters of the pores, for potential performance as a gas sensor device. The average thickness of the adsorbed film at low relative pressures is not affected by the pore size. Capillary evaporation of the liquid from the nanopores occurs at the liquid-vapor equilibrium described by the classical Kelvin equation with a hemispherical meniscus. Due to the almost complete wetting, we can quantitatively describe the condensation for isopropanol using the Cohan model with a cylindrical meniscus in the Kelvin equation. This model describes the observed hysteresis and allows us to use the adsorption branch of the isotherm to calculate the pore size distribution of the sample in good agreement with independent structural measurements. The condensation for toluene lacks reproducibility due to incomplete surface wetting. This exemplifies the relevant role of the fluid-solid (van der Waals) interactions in the hysteretic behavior of capillary condensation.

Gas adsorption and capillary condensation in nanoporous alumina films

International Nuclear Information System (INIS)

Casanova, Felix; Chiang, Casey E; Li, Chang-Peng; Roshchin, Igor V; Schuller, Ivan K; Ruminski, Anne M; Sailor, Michael J

2008-01-01

Gas adsorption and capillary condensation of organic vapors are studied by optical interferometry, using anodized nanoporous alumina films with controlled geometry (cylindrical pores with diameters in the range of 10-60 nm). The optical response of the film is optimized with respect to the geometric parameters of the pores, for potential performance as a gas sensor device. The average thickness of the adsorbed film at low relative pressures is not affected by the pore size. Capillary evaporation of the liquid from the nanopores occurs at the liquid-vapor equilibrium described by the classical Kelvin equation with a hemispherical meniscus. Due to the almost complete wetting, we can quantitatively describe the condensation for isopropanol using the Cohan model with a cylindrical meniscus in the Kelvin equation. This model describes the observed hysteresis and allows us to use the adsorption branch of the isotherm to calculate the pore size distribution of the sample in good agreement with independent structural measurements. The condensation for toluene lacks reproducibility due to incomplete surface wetting. This exemplifies the relevant role of the fluid-solid (van der Waals) interactions in the hysteretic behavior of capillary condensation

Gas adsorption and capillary condensation in nanoporous alumina films.

Science.gov (United States)

Casanova, Fèlix; Chiang, Casey E; Li, Chang-Peng; Roshchin, Igor V; Ruminski, Anne M; Sailor, Michael J; Schuller, Ivan K

2008-08-06

Gas adsorption and capillary condensation of organic vapors are studied by optical interferometry, using anodized nanoporous alumina films with controlled geometry (cylindrical pores with diameters in the range of 10-60 nm). The optical response of the film is optimized with respect to the geometric parameters of the pores, for potential performance as a gas sensor device. The average thickness of the adsorbed film at low relative pressures is not affected by the pore size. Capillary evaporation of the liquid from the nanopores occurs at the liquid-vapor equilibrium described by the classical Kelvin equation with a hemispherical meniscus. Due to the almost complete wetting, we can quantitatively describe the condensation for isopropanol using the Cohan model with a cylindrical meniscus in the Kelvin equation. This model describes the observed hysteresis and allows us to use the adsorption branch of the isotherm to calculate the pore size distribution of the sample in good agreement with independent structural measurements. The condensation for toluene lacks reproducibility due to incomplete surface wetting. This exemplifies the relevant role of the fluid-solid (van der Waals) interactions in the hysteretic behavior of capillary condensation.

Adsorption behavior of cation-exchange resin-mixed polyethersulfone-based fibrous adsorbents with bovine serum albumin

NARCIS (Netherlands)

Zhang, Y.; Zhang, Yuzhong; Borneman, Zandrie; Koops, G.H.; Wessling, Matthias

2006-01-01

The cation-exchange resin-mixed polyethersulfone (PES)-based fibrous adsorbents were developed to study their adsorption behavior with bovine serum albumin (BSA). A fibrous adsorbent with an open pore surface had much better adsorption behavior with a higher adsorbing rate. The adsorption capacity

Sulfur removal from fuel using zeolites/polyimide mixed matrix membrane adsorbents

International Nuclear Information System (INIS)

Lin, Ligang; Wang, Andong; Dong, Meimei; Zhang, Yuzhong; He, Benqiao; Li, Hong

2012-01-01

Graphical abstract: Membrane adsorption process is proposed for sulfur removal. Three-dimensional network structure is key to fulfill adsorption function of MMMs, which adsorption/desorption behavior is markedly related with binding force with sulfur molecules. Highlights: ► Membrane adsorption process is proposed for sulfur removal. ► Three-dimensional network structure of MMMs is key to fulfill adsorption function. ► Adsorption/desorption behavior is markedly related with binding force. - Abstract: A novel membrane adsorption process was proposed for the sulfur removal from fuels. The mixed matrix membranes (MMMs) adsorbents composed of polyimide (PI) and various Y zeolites were prepared. By the detailed characterization of FT-IR, morphology, thermal and mechanical properties of MMMs adsorbents, combining the adsorption and desorption behavior research, the process–structure–function relationship was discussed. Field-emission scanning electron microscope (FESEM) images show that the functional particles are incorporated into the three-dimensional network structure. MMMs adsorbents with 40% of zeolites content possess better physical properties, which was confirmed by mechanical strength and thermo stability analysis. Influence factors including post-treatment, content of incorporated zeolites, adsorption time, temperature, initial sulfur concentration as well as sulfur species on the adsorption performance of MMMs adsorbents have been evaluated. At 4 wt.% zeolites content, adsorption capacity for NaY/PI, AgY/PI and CeY/PI MMMs adsorbents come to 2.0, 7.5 and 7.9 mg S/g, respectively. And the regeneration results suggest that the corresponding spent membranes can recover about 98%, 90% and 70% of the desulfurization capacity, respectively. The distinct adsorption and desorption behavior of MMMs adsorbents with various functional zeolites was markedly related with their various binding force and binding mode with sulfur compounds.

Development of adsorbent for C-14 Gas trapping and characteristics evaluation

International Nuclear Information System (INIS)

Park, Geun Il; Kim, I. T.; Kim, K. W.

2006-08-01

Desorption characteristics of C-14 adsorbed on spent resin as H 14 CO 3 ion type by applying various stripping solutions were analyzed, and some experiments for gasification of C-14 to CO 2 gas with were also performed. Based on these results, the process concept for spent resin treatment was suggested. Real spent resin was prepared from sampling in storage tank in site 1 of Wolseung Nuclear Power Plant. Desorption characteristics of C-14 and cations of Cs, Co from spent IRN-150 resin was evaluated. Desorption efficiency of C-14 from spent resin by using H 3 PO 4 desorption solution was over 96% regardless of C-14 amount on initial spent resin when comparing a activity of C-14 on initial spent resin. Also, desorption percent of cation of Cs, Co from anion ion-exchange resin (IRN-77) showed that Co-60 was below 1%, Cs-134, 137 was in a range of 2 ∼ 5%. Fundamental studies include an development of adsorbent manufacturing technology and its performance evaluation for C-14 gas trapping, the adsorption process by adopting gas circulation method was suggested for the design of 14 CO 2 gas treatment system generated from spent resin treatment process. In order to predict adsorbent performance of CO 2 trapping, modelling was carried out to verify the breakthrough curves of CO 2 trapping by using soda lime adsorbent. The effect of humidity on CO 2 trapping by using soda lime adsorbent was modelled via chemical reaction in porous media. Assessment of the state-of-the-arts on the solidification of the used adsorbent showed that the cement matrix would be the best-available binder from the view points of the matrix compatibility, properties of the final waste form, simplicity of the process and relatively low cost

Zeolites as alcohol adsorbents from aqueous solutions

Directory of Open Access Journals (Sweden)

Cekova Blagica

2006-01-01

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.

Bicarbonate Elution of Uranium from Amidoxime-Based Polymer Adsorbents for Sequestering Uranium from Seawater

Energy Technology Data Exchange (ETDEWEB)

Pan, Horng-Bin [Department of Chemistry, University of Idaho, Moscow, Idaho 83844 USA; Wai, Chien M. [Department of Chemistry, University of Idaho, Moscow, Idaho 83844 USA; Kuo, Li-Jung [Pacific Northwest National Laboratory, Marine Sciences Laboratory, Sequim, Washington 98382 USA; Gill, Gary [Pacific Northwest National Laboratory, Marine Sciences Laboratory, Sequim, Washington 98382 USA; Tian, Guoxin [Lawrence Berkeley National Laboratory, Berkeley, California 94720 USA; Rao, Linfeng [Lawrence Berkeley National Laboratory, Berkeley, California 94720 USA; Das, Sadananda [Materials Science and Technology Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831 USA; Mayes, Richard T. [Materials Science and Technology Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831 USA; Janke, Christopher J. [Materials Science and Technology Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831 USA

2017-05-02

Uranium adsorbed on amidoxime-based polyethylene fibers in simulated seawater can be quantitatively eluted using 3 M KHCO3 at 40°C. Thermodynamic calculations are in agreement with the experimental observation that at high bicarbonate concentrations (3 M) uranyl ions bound to amidoxime molecules are converted to uranyl tris-carbonato complex in the aqueous solution. The elution process is basically the reverse reaction of the uranium adsorption process which occurs at a very low bicarbonate concentration (~10-3 M) in seawater. In real seawater experiments, the bicarbonate elution is followed by a NaOH treatment to remove natural organic matter adsorbed on the polymer adsorbent. Using the sequential bicarbonate and NaOH elution, the adsorbent is reusable after rinsing with deionized water and the recycled adsorbent shows no loss of uranium loading capacity based on real seawater experiments.

Supercritical fluid regeneration of adsorbents

Science.gov (United States)

Defilippi, R. P.; Robey, R. J.

1983-05-01

The results of a program to perform studies supercritical (fluid) carbon dioxide (SCF CO2) regeneration of adsorbents, using samples of industrial wastewaters from manufacturing pesticides and synthetic solution, and to estimate the economics of the specific wastewater treatment regenerations, based on test data are given. Processing costs for regenerating granular activated carbon GAC) for treating industrial wastewaters depend on stream properties and regeneration throughput.

Radiation-induced reactions of amino acids adsorbed on solid surfaces

Energy Technology Data Exchange (ETDEWEB)

Lopez-Esquivel Kranksith, L.; Negron-Mendoza, A. [Instituto de Ciencias Nucleares, Universidad Nacional Autonoma de Mexico, UNAM. Cd. Universitaria, A.P. 70-543, 04510 Mexico D.F. (Mexico); Mosqueira, F.G. [Direcion General de Divulgacion de la Ciencia, Universidad Nacional Autonoma de Mexico, Cd. Universitaria, AP. 70-487 Mexico D.F. (Mexico); Ramos-Bernal, Sergio, E-mail: ramos@nucleares.unam.m [Instituto de Ciencias Nucleares, Universidad Nacional Autonoma de Mexico, UNAM. Cd. Universitaria, A.P. 70-543, 04510 Mexico D.F. (Mexico)

2010-07-21

The purpose of this work is to study the adsorption of compounds such as amino acids on clays and carbon nanotubes (CNTs) as a possible phase in the chemical evolution that may have occurred on the primitive Earth or in extraterrestrial environments. We further study the behavior of amino acids adsorbed on these solid surfaces at different conditions of pH and levels of irradiation, simulating a high-radiation field at early Earth conditions. The relevance of this work is to explain the possible contribution of solids (clays and CNTs) as promoters of polymerization and as shields for the adsorbed organic compounds against external sources of energy. To this end, tryptophan, aspartic acid, and glutamic acid were adsorbed on fixed amounts of solid surfaces and were irradiated by a {sup 60}Co source for different periods of time at fixed dose rates. After irradiation, the amino acids were extracted from the solid and analyzed with UV and IR spectroscopes and high-performance liquid chromatography. The most efficient surface for adsorption of amino acids was clay, followed by CNTs. Studies of the gamma irradiation of amino acids adsorbed on clay (in the solid phase) show a low yield of recovery of the amino acid.

Synthesis and Characterization Pectin-Carboxymethyl Chitosan crosslinked PEGDE as biosorbent of Pb(II) ion

Science.gov (United States)

Hastuti, Budi; Siswanta, Dwi; Mudasir; Triyono

2018-01-01

Pectin and chitosan are biodegradable polymers, potentially applied as a heavy metal adsorbents. Unfortunately both biosorbents pectin and chitosan have a weakness in acidic media. For this purpose required modified pectin and chitosan. The modified adsorben is intended to obtain a stable adsorbent and resistance under acid. The research was done by experimental method in laboratory. The stages of this research are the synthesis of carboxymethyl chitosan (CMC), synthesis of Pec-CMC-PEGDE film adsorbent, stabily test under acid, the characterization of active group using FTIR, stability characterization of Pec-CMC-PEGDE powder adsorbent using XRD, termo stability using DTA-TGA. The results of the research have shown that: pectin and CMC can be cross-linked using PEGDE crosslinking agent, the film adsorbent was stable under HCl 1 M, the film adsorbent have active group comprise of carboxylate and amine groups. The result of characterization using XRD, shows that the adsorbent is semi-crystalline. Base on termo stability, the film adsorbent Pec-CMC-PEGDE stable up to 600°C. The film can be applied as an adsobent of Pb (II) ion remediation. The optimum pH of pec-CMC-PEGDE in adsorbed of Pb(II) was reached at pH 5 with 99.99% absorbent adsorbed and of and adsorption capacity was 46.11 mg/g.

Single-domain epitaxial silicene on diboride thin films

Energy Technology Data Exchange (ETDEWEB)

Fleurence, A., E-mail: antoine@jaist.ac.jp; Friedlein, R.; Aoyagi, K.; Yamada-Takamura, Y. [School of Materials Science, Japan Advanced Institute of Science and Technology (JAIST), 1-1 Asahidai, Nomi, Ishikawa 923-1292 (Japan); Gill, T. G. [School of Materials Science, Japan Advanced Institute of Science and Technology (JAIST), 1-1 Asahidai, Nomi, Ishikawa 923-1292 (Japan); London Centre for Nanotechnology, University College London (UCL), London WC1H 0AH (United Kingdom); Department of Chemistry, UCL, London WC1H 0AJ (United Kingdom); Sadowski, J. T. [Center for Functional Nanomaterials, Brookhaven National Laboratory, Upton, New York 11973 (United States); Copel, M.; Tromp, R. M. [IBM Research Division, Thomas J. Watson Research Center, Yorktown Heights, New York 10598 (United States); Hirjibehedin, C. F. [London Centre for Nanotechnology, University College London (UCL), London WC1H 0AH (United Kingdom); Department of Chemistry, UCL, London WC1H 0AJ (United Kingdom); Department of Physics and Astronomy, UCL, London WC1E 6BT (United Kingdom)

2016-04-11

Epitaxial silicene, which forms spontaneously on ZrB{sub 2}(0001) thin films grown on Si(111) wafers, has a periodic stripe domain structure. By adsorbing additional Si atoms on this surface, we find that the domain boundaries vanish, and a single-domain silicene sheet can be prepared without altering its buckled honeycomb structure. The amount of Si required to induce this change suggests that the domain boundaries are made of a local distortion of the silicene honeycomb lattice. The realization of a single domain sheet with structural and electronic properties close to those of the original striped state demonstrates the high structural flexibility of silicene.

Nicotinic acid as a new co-adsorbent in dye-sensitized solar cells

DEFF Research Database (Denmark)

Nguyen, Phuong Tuyet; Nguyen, Vinh Son; Pham Phan, Thu Anh

2017-01-01

With the aim of introduction a new inexpensive co-adsorbent to improve solar cell performance, the influence of nicotinic acid (NTA) used as a co-adsorbent in dye-sensitized solar cells (DSCs) was investigated. The findings showed that low concentrations of NTA (

A Method for Field Calibration of the PA260 Phosphorus Analyzer Using Solid Adsorbent Materials

Science.gov (United States)

1989-12-01

plant environment. The solid adsorbent approach has two major advantages over other traditional air sampling devices such as bubblers or impingers...GC (60/80 mesh) or Chromosorb 106 (80/100 mesh). Both adsorbents were supplied by Alltech Associates (Deerfield, IL). The adsorbents were packed in

Surface-enhanced Raman Spectroscopy of Ethephone Adsorbed on Silver Surface

International Nuclear Information System (INIS)

Lee, Chul Jae; Kim, Hee Jin; Karim, Mohammad Rezaul; Lee, Mu Sang

2006-01-01

We investigated the Surface-enhanced Raman Spectroscopy (SERS) spectrum of ethephone (2- chloroethylphosphonic acid). We observed significant signals in the ordinary Raman spectrum for solid-state ethephone as well as when it was adsorbed on a colloidal silver surface, strong vibrational signals were obtained at a very low concentration. The SERS spectra were obtained by silver colloids that were prepared by the γ - irradiation method. The influence of pH and the influence of anion (Cl - , Br - , I - ) on the adsorption orientation were investigated. Two different adsorption mechanisms were deduced, depending on the experimental conditions. The chlorine atom or the chlorine and two oxygen atoms were adsorbed on the colloidal silver surface. Among halide ions, Br - and I - were more strongly adsorbed on the colloidal silver surfaces. As a result, the adsorption of ethephone was less effective due to their steric hinderance

On the nucleation and initial film growth of rod-like organic molecules

Science.gov (United States)

Winkler, Adolf

2016-10-01

In this article, some fundamental topics related to the initial steps of organic film growth are reviewed. General conclusions will be drawn based on experimental results obtained for the film formation of oligophenylene and pentacene molecules on gold and mica substrates. Thin films were prepared via physical vapor deposition under ultrahigh-vacuum conditions and characterized in-situ mainly by thermal desorption spectroscopy, and ex-situ by X-ray diffraction and atomic force microscopy. In this short review article the following topics will be discussed: What are the necessary conditions to form island-like films which are either composed of flat-lying or of standing molecules? Does a wetting layer exist below and in between the islands? What is the reason behind the occasionally observed bimodal island size distribution? Can one describe the nucleation process with the diffusion-limited aggregation model? Do the impinging molecules directly adsorb on the surface or rather via a hot-precursor state? Finally, it will be described how the critical island size can be determined by an independent measurement of the deposition rate dependence of the island density and the capture-zone distribution via a universal relationship.

Transparent, Ultrahigh-Gas-Barrier Films with a Brick-Mortar-Sand Structure.

Science.gov (United States)

Dou, Yibo; Pan, Ting; Xu, Simin; Yan, Hong; Han, Jingbin; Wei, Min; Evans, David G; Duan, Xue

2015-08-10

Transparent and flexible gas-barrier materials have shown broad applications in electronics, food, and pharmaceutical preservation. Herein, we report ultrahigh-gas-barrier films with a brick-mortar-sand structure fabricated by layer-by-layer (LBL) assembly of XAl-layered double hydroxide (LDH, X=Mg, Ni, Zn, Co) nanoplatelets and polyacrylic acid (PAA) followed by CO2 infilling, denoted as (XAl-LDH/PAA)n-CO2. The near-perfectly parallel orientation of the LDH "brick" creates a long diffusion length to hinder the transmission of gas molecules in the PAA "mortar". Most significantly, both the experimental studies and theoretical simulations reveal that the chemically adsorbed CO2 acts like "sand" to fill the free volume at the organic-inorganic interface, which further depresses the diffusion of permeating gas. The strategy presented here provides a new insight into the perception of barrier mechanism, and the (XAl-LDH/PAA)n-CO2 film is among the best gas barrier films ever reported. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Alkali metal adsorbate sputtering by molecular impact

International Nuclear Information System (INIS)

Moran, J.P.; Wachman, H.Y.; Trilling, L.

1974-01-01

An exploratory study of the sputtering by a krypton molecular beam of rubidium adsorbed at low coverage on a tungsten substrate has been described in a previous paper. An extension of this work is reported now

Adsorptive desulfurization of model oil using untreated, acid activated and magnetite nanoparticle loaded bentonite as adsorbent

Directory of Open Access Journals (Sweden)

Muhammad Ishaq

2017-02-01

Full Text Available The present research work focuses on a novel ultraclean desulfurization process of model oil by the adsorption method using untreated, acid activated and magnetite nanoparticle loaded bentonite as adsorbent. The parameters investigated are effect of contact time, adsorbent dose, initial dibenzothiophene (DBT concentration and temperature. Experimental tests were conducted in batch process. Pseudo first and second order kinetic equations were used to examine the experimental data. It was found that pseudo second order kinetic equation described the data of the DBT adsorption onto all types of adsorbents very well. The isotherm data were analyzed using Langmuir and Freundlich isotherm models. The Langmuir isotherm model fits the data very well for the adsorption of DBT onto all three forms of adsorbents. The adsorption of DBT was also investigated at different adsorbent doses and was found that the percentage adsorption of DBT was increased with increasing the adsorbent dose, while the adsorption in mg/g was decreased with increasing the adsorbent dose. The prepared adsorbents were analyzed by scanning electron microscopy (SEM, energy dispersive X-ray spectrometry (EDX and X-ray diffraction (XRD.

Investigation on the adsorption characteristics of sodium benzoate and taurine on gold nanoparticle film by ATR-FTIR spectroscopy

Science.gov (United States)

Kumar, Naveen; Thomas, S.; Tokas, R. B.; Kshirsagar, R. J.

2014-01-01

Fourier transform infrared (FTIR) spectroscopic studies of sodium benzoate and taurine adsorbed on gold nanoparticle (AuNp) film on silanised glass slides have been studied by attenuated total reflection technique (ATR). The surface morphology of the AuNp films has been measured by Atomic Force Microscopy. The ATR spectra of sodium benzoate and taurine deposited on AuNp film are compared with ATR spectra of their powdered bulk samples. A new red-shifted band appeared along with the symmetric and asymmetric stretches of carboxylate group of sodium benzoate leading to a broadening of the above peaks. Similar behavior is also seen in the case of symmetric and asymmetric stretches of sulphonate group of taurine. The results indicate presence of both chemisorbed and physisorbed layers of both sodium benzoate and taurine on the AuNp film with bottom layer chemically bound to AuNp through carboxylate and sulphonate groups respectively.

Formation and enzymatic degradation of poly-l-arginine/fucoidan multilayer films.

Science.gov (United States)

Webber, Jessie L; Benbow, Natalie L; Krasowska, Marta; Beattie, David A

2017-11-01

A polyelectrolyte multilayer (PEM) system based on biopolymers has been constructed and studied in its formation and enzymatic breakdown. The multilayer is composed of fucoidan (a proven antimicrobial/anti-inflammatory seaweed-based polysaccharide) and poly-l-arginine (a polypeptide that can be readily degraded with trypsin to yield arginine, a known NO donor), thus making the multilayer a potential dual action surface treatment for wound dressings. Studies on the formation of the multilayer revealed that the film built-up in the expected stepwise manner with consistent reversal of the zeta potential upon the adsorption of each subsequent polyion. The completed film (8 bilayers) was seen to have low hydration (30% water), as determined by H 2 O/D 2 O solvent replacement studies using the quartz crystal microbalance, with an adsorbed mass (without hydration water) of approx. 4.8μgcm -2 , as determined by quantitative attenuated total reflectance Fourier transform infrared (ATR FTIR) spectroscopy. The enzymatic breakdown of the film in response to exposure to trypsin was also investigated, and the film was seen to release both polymers over time, with a projected complete film removal period of approximately 24h. Critically, this information was determined using ATR FTIR spectroscopy experiments, which allowed unambiguous deconvolution of the removal rates of the two polyions, which is information that cannot be obtained from other methodologies used to study enzymatic breakdown of surface films. Copyright © 2017 Elsevier B.V. All rights reserved.

Oxidation of adsorbed ferrous iron: kinetics and influence of process conditions.

Science.gov (United States)

Buamah, R; Petrusevski, B; Schippers, J C

2009-01-01

For the removal of iron from groundwater, aeration followed with rapid (sand) filtration is frequently applied. Iron removal in this process is achieved through oxidation of Fe(2 + ) in aqueous solution followed by floc formation as well as adsorption of Fe(2 + ) onto the filter media. The rate of oxidation of the adsorbed Fe(2 + ) on the filter media plays an important role in this removal process. This study focuses on investigating the effect of pH on the rate of oxidation of adsorbed Fe(2 + ). Fe(2 + ) has been adsorbed, under anoxic conditions, on iron oxide coated sand (IOCS) in a short filter column and subsequently oxidized by feeding the column with aerated water. Ferrous ions adsorbed at pH 5, 6, 7 and 8 demonstrated consumption of oxygen, when aerated water was fed into the column. The oxygen uptake at pH 7 and 8 was faster than at pH 5 and 6. However the difference was less pronounced than expected. The difference is attributed to the pH buffering effect of the IOCS. At feedwater pH 5, 6 and 7 the pH in the effluent was higher than in the influent, while a pH drop should occur because of oxidation of adsorbed Fe(2 + ). At pH 8, the pH dropped. These phenomena are attributed to the presence of calcium and /or ferrous carbonate in IOCS.

Structure and phase transitions of monolayers of intermediate-length n-alkanes on graphite studied by neutron diffraction and molecular dynamics simulation

Science.gov (United States)

Diama, A.; Matthies, B.; Herwig, K. W.; Hansen, F. Y.; Criswell, L.; Mo, H.; Bai, M.; Taub, H.

2009-08-01

We present evidence from neutron diffraction measurements and molecular dynamics (MD) simulations of three different monolayer phases of the intermediate-length alkanes tetracosane (n-C24H50 denoted as C24) and dotriacontane (n-C32H66 denoted as C32) adsorbed on a graphite basal-plane surface. Our measurements indicate that the two monolayer films differ principally in the transition temperatures between phases. At the lowest temperatures, both C24 and C32 form a crystalline monolayer phase with a rectangular-centered (RC) structure. The two sublattices of the RC structure each consists of parallel rows of molecules in their all-trans conformation aligned with their long axis parallel to the surface and forming so-called lamellas of width approximately equal to the all-trans length of the molecule. The RC structure is uniaxially commensurate with the graphite surface in its [110] direction such that the distance between molecular rows in a lamella is 4.26 Å=√3 ag, where ag=2.46 Å is the lattice constant of the graphite basal plane. Molecules in adjacent rows of a lamella alternate in orientation between the carbon skeletal plane being parallel and perpendicular to the graphite surface. Upon heating, the crystalline monolayers transform to a "smectic" phase in which the inter-row spacing within a lamella expands by ˜10% and the molecules are predominantly oriented with the carbon skeletal plane parallel to the graphite surface. In the smectic phase, the MD simulations show evidence of broadening of the lamella boundaries as a result of molecules diffusing parallel to their long axis. At still higher temperatures, they indicate that the introduction of gauche defects into the alkane chains drives a melting transition to a monolayer fluid phase as reported previously.

Synthesis of magnetic ordered mesoporous carbon (Fe-OMC) adsorbent and its evaluation for fuel desulfurization

Science.gov (United States)

Farzin Nejad, N.; Shams, E.; Amini, M. K.

2015-09-01

In this work, magnetic ordered mesoporous carbon adsorbent was synthesized using soft templating method to adsorb sulfur from model oil (dibenzothiophene in n-hexane). Through this research, pluronic F-127, resorcinol-formaldehyde and hydrated iron nitrate were respectively used as soft template, carbon source and iron source. The adsorbent was characterized by X-ray diffraction, nitrogen adsorption-desorption isotherm and transmission electron microscopy. Nitrogen adsorption-desorption measurement revealed the high surface area (810 m2 g-1), maxima pore size of 3.3 nm and large pore volume (1.01 cm3 g-1) of the synthesized sample. The adsorbent showed a maximum adsorption capacity of 111 mg dibenzothiophene g-1 of adsorbent. Sorption process was described by the pseudo-second-order rate equation and could be better fitted by the Freundlich model, showing the heterogeneous feature of the adsorption process. In addition, the adsorption capacity of regenerated adsorbent was 78.6% of the initial level, after five regeneration cycles.

Stable Nafion-functionalized graphene dispersions for transparent conducting films

International Nuclear Information System (INIS)

Liu Yangqiao; Gao Lian; Sun Jing; Wang Yan; Zhang Jing

2009-01-01

Nafion was used for the first time to aid in preparing stable graphene dispersions in mixed water/ethanol (1:1) solvents via the reduction of graphite oxide using hydrazine. The dispersion was characterized by ultraviolet-visible (UV-vis) spectra, transmission electron microscopy, zeta potential analysis, etc. It was found that for Nafion-to-graphene ratios higher than 5:1, graphene solutions with concentrations up to 1 mg ml -1 and stabilities of over three months were obtained. It was proposed that the Nafion adsorbed onto the graphene by the hydrophobic interaction of its fluoro-backbones with the graphene layer and imparted stability by an electrosteric mechanism. Furthermore, transparent and conductive films were prepared using these highly stable Nafion-stabilized graphene dispersions. The prepared Nafion-graphene films possess smooth and homogeneous surfaces and the sheet resistance was as low as 30 kΩ/sq for a transmittance of 80% at 550 nm, which was much lower than for other graphene films obtained by chemical reduction. X-ray photoelectron spectroscopy and Raman spectroscopy confirmed the p-doping of the graphene by Nafion. It was expected that this p-doping effect, as well as the high dispersing ability of Nafion for graphene and the connection of the sp 2 domains by residual Nafion combined to produce good properties of the Nafion-graphene films.

Investigation on removal of malachite green using EM based compost as adsorbent.

Science.gov (United States)

Bhagavathi Pushpa, T; Vijayaraghavan, J; Sardhar Basha, S J; Sekaran, V; Vijayaraghavan, K; Jegan, J

2015-08-01

The discarded materials from different sources can be utilized as effective materials in wastewater remediation. This proposed study was aimed mainly to investigate the possibility of Effective Microorganisms based compost (EMKC), which is derived from the kitchen solid waste, as a non-conventional low cost adsorbent for the removal of malachite green from aqueous solution. Batch experiments were carried out to evaluate the optimum operating parameters like pH (2-9), initial dye concentration (50-1000mg/L), adsorbent particle size (0.6-2.36mm) and adsorbent dosage (2-12g/L). EMKC recorded maximum uptake of 136.6mg/g of MG at pH 8, initial dye concentration 1000mg/L, adsorbent particle size 1.18mm and adsorbent dosage 4g/L. Two and three parameter adsorption models were employed to describe experimental biosorption isotherm data. The results revealed that the Sips model resulted in better fit than other models. The pseudo-first and -second order models were applied to describe kinetic data, of which the pseudo-second order described experimental data better with high correlation coefficient. This investigation suggested that EMKC could be an effective and low cost material for the removal of malachite green dye from aqueous solution. Copyright © 2015 Elsevier Inc. All rights reserved.

Heat capacity of xenon adsorbed in nanobundle grooves

International Nuclear Information System (INIS)

Chishko, K.A.; Sokolova, E.S.

2016-01-01

A model of one-dimensional real gas under external transverse force field is applied to interpret the experimentally observed thermodynamical properties of xenon deposited into groves on the surface of carbon nanobundles. This non-ideal gas model with pair interaction is not quite adequate to describe the dense adsorbates (especially at low temperature limit), but it makes possible to take into account easily the particle exchange between 1D adsorbate and 3D atmosphere which becomes an essential factor since intermediate (for xenon - of order 35 K) up to high (approx 100 K) temperatures. In this paper we treat the 1D real gas with only Lennard-Jones pair interaction, but at presence of exact equilibrium conditions on the atom numbers between low-dimensional adsorbate and three-dimensional atmosphere of the experimental cell. The low-temperature branch of the heat capacity has been fitted separately within the elastic atomic chain model to get the best agreement between theory and experiment in as wide as possible region just from zero temperature. The gas approximation is introduced from the temperatures where the chain heat capacity tends definitely to 1D equipartition law. In this case the principal parameters for both models can be chosen in such a way that the heat capacity C(T) of the chain goes continuously into the corresponding curve of the gas approximation. So, it seems to be expected that adequate interpretation for temperature dependences of the atomic adsorbate heat capacity can be obtained through a reasonable combination of 1D gas and phonon approaches. The principal parameters of the gas approximation (such a desorption energy) found from the fitting between theory and experiment for xenon heat capacity are in good agreement with corresponding data known in literature.

Synovial fluid lubrication of artificial joints: protein film formation and composition.

Science.gov (United States)

Fan, Jingyun; Myant, Connor; Underwood, Richard; Cann, Philippa

2012-01-01

Despite design improvements, wear of artificial implants remains a serious health issue particularly for Metal-on-Metal (MoM) hips where the formation of metallic wear debris has been linked to adverse tissue response. Clearly it is important to understand the fundamental lubrication mechanisms which control the wear process. It is usually assumed that MoM hips operate in the ElastoHydrodynamic Lubrication (EHL) regime where film formation is governed by the bulk fluid viscosity; however there is little experimental evidence of this. The current paper critically examines synovial fluid lubrication mechanisms and the effect of synovial fluid chemistry. Two composition parameters were chosen; protein content and pH, both of which are known to change in diseased or post-operative synovial fluid. Film thickness and wear tests were carried out for a series of model synovial fluid solutions. Two distinct film formation mechanisms were identified; an adsorbed surface film and a high-viscosity gel. The entrainment of this gel controls film formation particularly at low speeds. However wear of the femoral head still occurs and this is thought to be due primarily to a tribo-corrosion mechanisms. The implications of this new lubrication mechanism and the effect of different synovial fluid chemistries are examined. One important conclusion is that patient synovial fluid chemistry plays an important role in determining implant wear and the likelihood of failure.

Simultaneous measurement of trace metal and oxyanion concentrations in water using diffusive gradients in thin films with a chelex-metsorb mixed binding layer

DEFF Research Database (Denmark)

Panther, Jared G.; Bennett, William W.; Welsh, David T.

2014-01-01

A new diffusive gradients in thin films (DGT) technique with a mixed binding layer (Chelex-100 and the titanium dioxide based adsorbent Metsorb) is described for the simultaneous measurement of labile trace metal (Mn, Co, Ni, Cu, Cd, and Pb) and oxyanion (V, As, Mo, Sb, W, and P) concentrations i...

Treatment of Refinery Waste Water Using Environmental Friendly Adsorbent

Science.gov (United States)

Devi, M. Geetha; Al-Moshrafi, Samira Mohammed Khamis; Al Hudaifi, Alaa; Al Aisari, Buthaina Hamood

2017-12-01

This research evaluates the effectiveness of activated carbon prepared from walnut shell in the removal of pollutants from refinery waste water by adsorption technique. A series of batch experiments were carried out by varying the effluent solution pH, stirring time, stirring speed and adsorbent dosage in the reduction of pollutants from refinery effluent. Characterization of the adsorbent was performed using Scanning Electron Microscopy (SEM), Brunauer Emmett and Teller (BET) isotherm and Fourier Transform Infrared (FTIR) Spectroscopy. The best quality activated carbon was obtained with a particle size of 0.75 µm, activation temperature of 800 °C and activation time 24 h. The maximum BET surface area obtained was 165.2653 m2/g. The experimental results demonstrates that the highest percentage reduction in COD was 79%, using 0.6 g walnut shell powder at an optimum stirring speed of 100 rpm, at pH 6 and 120 min of contact time. The outcome of the result shows that walnut shell carbon is a potentially useful adsorbent for the removal of pollutants from refinery waste water.

Novel transparent and flexible nanocomposite film prepared from chrysotile nanofibres

Energy Technology Data Exchange (ETDEWEB)

Liu, Kun, E-mail: kliu@csu.edu.cn [School of Minerals Processing and Bioengineering, Central South University, Changsha 410083 (China); Zhu, Binnan; Feng, Qiming [School of Minerals Processing and Bioengineering, Central South University, Changsha 410083 (China); Duan, Tao [Joint Laboratory for Extreme Conditions Matter Properties, Southwest University of Science and Technology and Research Center of Laser Fusion, CAEP, Mianyang 621010 (China)

2013-10-01

In the present study, chrysotile nanofibres, obtained from physicochemical dispersion of natural chrysotile, were used to prepare nanofibre sheets by vacuum filtration. As-prepared sheets were then impregnated by UV-curable resin and cured by ultraviolet light to fabricate the flexible and transparent nanocomposite films. Observed from SEM, the transparent films showed a smooth surface and a typical sandwich structure in cross section, viz. nanofibre sheet filled with resin was sandwiched by two layers of resin. XRD patterns indicated the amorphous nature of cured resin and characteristic crystallographic structure of chrysotile in nanocomposite films. Though the nanofibre sheets were white in colour, and nanofibre contents in nanocomposites were as much as 43.4 wt%, the nanocomposite films displayed an excellent optical transparency with about 85% light transmittance in the visible light range. Tensile tests showed that the addition of nanofibres resulted in a great improvement in mechanical strength of the nanocomposite films; with the increase of nanofibre contents, the modulus and tensile strength of nanocomposite films increased gradually. - Graphical abstract: Photos show the experimental phenomenon. The white nanofibre sheets can be written or printed like paper, and it's very interested that the handwriting is clearly visible from the front and back of the transparent films prepared from nanofibre sheets by vacuum impregnation and UV curing. This phenomenon can be attributed to the increase of transparency of film, which results from the replacement of air interstices in nanofibre sheet by resin with higher refractive index. Visible light can pass easily through the transparent film without obvious loss, but can be apparently adsorbed and scattered by ink particles that adhered to nanofibres and embedded in resin. - Highlights: • A flexible and transparent film is prepared from chrysotile nanofibres. • The nanofibre sheet is sandwiched by two

Novel transparent and flexible nanocomposite film prepared from chrysotile nanofibres

International Nuclear Information System (INIS)

Liu, Kun; Zhu, Binnan; Feng, Qiming; Duan, Tao

2013-01-01

In the present study, chrysotile nanofibres, obtained from physicochemical dispersion of natural chrysotile, were used to prepare nanofibre sheets by vacuum filtration. As-prepared sheets were then impregnated by UV-curable resin and cured by ultraviolet light to fabricate the flexible and transparent nanocomposite films. Observed from SEM, the transparent films showed a smooth surface and a typical sandwich structure in cross section, viz. nanofibre sheet filled with resin was sandwiched by two layers of resin. XRD patterns indicated the amorphous nature of cured resin and characteristic crystallographic structure of chrysotile in nanocomposite films. Though the nanofibre sheets were white in colour, and nanofibre contents in nanocomposites were as much as 43.4 wt%, the nanocomposite films displayed an excellent optical transparency with about 85% light transmittance in the visible light range. Tensile tests showed that the addition of nanofibres resulted in a great improvement in mechanical strength of the nanocomposite films; with the increase of nanofibre contents, the modulus and tensile strength of nanocomposite films increased gradually. - Graphical abstract: Photos show the experimental phenomenon. The white nanofibre sheets can be written or printed like paper, and it's very interested that the handwriting is clearly visible from the front and back of the transparent films prepared from nanofibre sheets by vacuum impregnation and UV curing. This phenomenon can be attributed to the increase of transparency of film, which results from the replacement of air interstices in nanofibre sheet by resin with higher refractive index. Visible light can pass easily through the transparent film without obvious loss, but can be apparently adsorbed and scattered by ink particles that adhered to nanofibres and embedded in resin. - Highlights: • A flexible and transparent film is prepared from chrysotile nanofibres. • The nanofibre sheet is sandwiched by two

Poorly crystalline hydroxyapatite: A novel adsorbent for enhanced fulvic acid removal from aqueous solution

Energy Technology Data Exchange (ETDEWEB)

Wei, Wei [Department of Environmental Science and Engineering, Nanjing Normal University, Nanjing 210023 (China); Jiangsu Provincial Key Laboratory of Materials Cycling and Pollution Control, Nanjing Normal University, Nanjing 210023 (China); Jiangsu Center for Collaborative Innovation in Geographical Information Resource Development and Application, Nanjing Normal University, Nanjing 210023 (China); Yang, Lei; Zhong, Wenhui; Cui, Jing [Department of Environmental Science and Engineering, Nanjing Normal University, Nanjing 210023 (China); Wei, Zhenggui, E-mail: weizhenggui@gmail.com [Department of Environmental Science and Engineering, Nanjing Normal University, Nanjing 210023 (China); Jiangsu Provincial Key Laboratory of Materials Cycling and Pollution Control, Nanjing Normal University, Nanjing 210023 (China); Jiangsu Center for Collaborative Innovation in Geographical Information Resource Development and Application, Nanjing Normal University, Nanjing 210023 (China)

2015-03-30

Graphical abstract: - Highlights: • Poorly crystalline HAP was firstly used for FA removal from aqueous solution. • The maximum adsorption capacity was determined to be 90.20 mg/g at 318 K. • Adsorption kinetics, isotherms and thermodynamic have been studied in detail. • Adsorption mechanism involved surface complexation, electrostatic interaction and hydrogen bonding. - Abstract: In this study, poorly crystalline hydroxyapatite (HAP) was developed as an efficient adsorbent for the removal of fulvic acid (FA) from aqueous solution. Surface functionality, crystallinity, and morphology of the synthetic adsorbent were studied by Fourier-transformation infrared (FT-IR) spectroscopy, powder X-ray diffraction (XRD) and transmission electron microscopy (TEM). The effects of various parameters such as crystallinity of adsorbent, contact time, adsorbent dosage, pH, initial adsorbate concentration, temperature, ionic strength and the presence of alkaline earth metal ions on FA adsorption were investigated. Results indicated that the nanosized HAP calcined at lower temperature was poorly crystalline (X{sub c} = 0.23) and had better adsorption capacity for FA than those (X{sub c} = 0.52, 0.86) calcined at higher temperature. FA removal was increased with increases of adsorbent dosage, temperature, ionic strength and the presence of alkali earth metal ions, but decreased as the pH increased. Kinetic studies showed that pseudo-second-order kinetic model better described the adsorption process. Equilibrium data were best described by Sips models, and the estimated maximum adsorption capacity of poorly crystalline HAP was 90.20 mg/g at 318 K, displaying higher efficiency for FA removal than previously reported adsorbents. FT-IR results revealed that FA adsorption over the adsorbent could be attributed to the surface complexation between the oxygen atom of functional groups of FA and calcium ions of HAP. Regeneration studies indicated that HAP could be recyclable for a long

Heating and cooling system for an on-board gas adsorbent storage vessel

Science.gov (United States)

Tamburello, David A.; Anton, Donald L.; Hardy, Bruce J.; Corgnale, Claudio

2017-06-20

In one aspect, a system for controlling the temperature within a gas adsorbent storage vessel of a vehicle may include an air conditioning system forming a continuous flow loop of heat exchange fluid that is cycled between a heated flow and a cooled flow. The system may also include at least one fluid by-pass line extending at least partially within the gas adsorbent storage vessel. The fluid by-pass line(s) may be configured to receive a by-pass flow including at least a portion of the heated flow or the cooled flow of the heat exchange fluid at one or more input locations and expel the by-pass flow back into the continuous flow loop at one or more output locations, wherein the by-pass flow is directed through the gas adsorbent storage vessel via the by-pass line(s) so as to adjust an internal temperature within the gas adsorbent storage vessel.

Analysis of Adsorbed Natural Gas Tank Technology

Science.gov (United States)

Knight, Ernest; Schultz, Conrad; Rash, Tyler; Dohnke, Elmar; Stalla, David; Gillespie, Andrew; Sweany, Mark; Seydel, Florian; Pfeifer, Peter

With gasoline being an ever decreasing finite resource and with the desire to reduce humanity's carbon footprint, there has been an increasing focus on innovation of alternative fuel sources. Natural gas burns cleaner, is more abundant, and conforms to modern engines. However, storing compressed natural gas (CNG) requires large, heavy gas cylinders, which limits space and fuel efficiency. Adsorbed natural gas (ANG) technology allows for much greater fuel storage capacity and the ability to store the gas at a much lower pressure. Thus, ANG tanks are much more flexible in terms of their size, shape, and weight. Our ANG tank employs monolithic nanoporous activated carbon as its adsorbent material. Several different configurations of this Flat Panel Tank Assembly (FPTA) along with a Fuel Extraction System (FES) were examined to compare with the mass flow rate demands of an engine.

Structures of adsorbed CO on atomically smooth and on stepped sngle crystal surfaces

International Nuclear Information System (INIS)

Madey, T.E.; Houston, J.E.

1980-01-01

The structures of molecular CO adsorbed on atomically smooth surfaces and on surfaces containing monatomic steps have been studied using the electron stimulated desorption ion angular distribution (ESDIAD) method. For CO adsorbed on the close packed Ru(001) and W(110) surfaces, the dominant bonding mode is via the carbon atom, with the CO molecular axis perpendicular to the plane of the surface. For CO on atomicaly rough Pd(210), and for CO adsorbed at step sites on four different surfaces vicinal to W(110), the axis of the molecule is tilted or inclined away from the normal to the surface. The ESDIAD method, in which ion desorption angles are related to surface bond angles, provides a direct determination of the structures of adsorbed molecules and molecular complexes on surfaces

MODIFICATION OF KELUD VOLCANIC ASH 2014 AS SELECTIVE ADSORBENT MATERIAL FOR COPPER(II METAL ION

Directory of Open Access Journals (Sweden)

Susila Kristianingrum

2017-01-01

  This research aims to prepare an adsorbent from Kelud volcanic ash for better Cu(II adsorption efficiency than Kiesel gel 60G E'Merck. Adsorbent synthesis was done by dissolving 6 grams of volcanic ash activated 700oC 4 hours and washed with HCl 0.1 M into 200 ml of 3M sodium hydroxide with stirring and heating of 100 °C for 1 hour. The filtrate sodium silicate was then neutralized using sulfuric acid. The mixture was allowed to stand for 24 hours then filtered and washed with aquaDM, then dried and crushed. The procedure is repeated for nitric acid, acetic acid and formic acid with a contact time of 24 hours. The products were then characterized using FTIR and XRD, subsequently determined acidity, moisture content, and tested for its adsorption of the ion Cu (II with AAS. The results showed that the type of acid that produced highest rendemen is AK-H2SO4-3M ie 36.93%, acidity of the adsorbent silica gel synthesized similar to Kiesel gel 60G E'Merck ie adsorbent AK-CH3COOH-3M and the water content of the silica gel adsorbent synthesized similar to Kiesel gel 60G E'Merck ie adsorbent AK-H2SO4-2 M. The character of the functional groups of silica gel synthesized all have similarities with Kiesel gel 60G E'Merck as a comparison. Qualitative analysis by XRD for all modified adsorbent showed a dominant peak of SiO2 except adsorbent AK-H2SO4 amorphous and chemical bonds with FTIR indicates that it has formed a bond of Si-O-Si and Si-OH. The optimum adsorption efficiency of the metal ions Cu(II obtained from AK-H2SO4-5M adsorbent that is equal to 93.2617% and the optimum adsorption capacity of the Cu(II metal ions was obtained from the adsorbent AK-CH3COOH-3M is equal to 2.4919 mg/ g.   Keywords: adsorbents, silica gel, adsorption, kelud volcanic ash

Natural material adsorbed onto a polymer to enhance immune function

Directory of Open Access Journals (Sweden)

Reinaque AP

2012-08-01

Full Text Available Ana Paula Barcelos Reinaque,1 Eduardo Luzía França,2 Edson Fredulin Scherer,3 Mayra Aparecida Côrtes,1 Francisco José Dutra Souto,4 Adenilda Cristina Honorio-França51Post Graduate Program in Material Science, 2Institute of Biological and Health Science, Federal University of Mato Grosso, Barra do Garças, 3Post Graduate Program in Material Science, Institute of Biological and Health Science, Federal University of Mato Grosso, Pontal do Araguaia, 4Faculty of Medical Sciences, Federal University of Mato Grosso, Cuiabá, 5Institute of Biological and Health Science, Federal University of Mato Grosso, Pontal do Araguaia, MT, BrazilBackground: In this study, we produced poly(ethylene glycol (PEG microspheres of different sizes and adsorbing a medicinal plant mixture, and verified their effect in vitro on the viability, superoxide production, and bactericidal activity of phagocytes in the blood.Methods: The medicinal plant mixture was adsorbed onto PEG microspheres and its effects were evaluated by flow cytometry and fluorescence microscopy.Results: Adsorption of the herbal mixture onto the PEG microspheres was achieved and the particles were internalized by phagocytes. PEG microspheres bearing the adsorbed herbal mixture stimulated superoxide release, and activated scavenging and microbicidal activity in phagocytes. No differences in functional activity were observed when the phagocytes were not incubated with PEG microspheres bearing the adsorbed herbal mixture.Conclusion: This system may be useful for the delivery of a variety of medicinal plants and can confer additional protection against infection. The data reported here suggest that a polymer adsorbed with a natural product is a treatment alternative for enhancing immune function.Keywords: natural product, polymer, adsorption, immune function, phagocytes

Properties and behaviour of SO{sub 2} adsorbents for CFBC

Energy Technology Data Exchange (ETDEWEB)

Smith, I.M.

2007-11-15

Sulphur capture in FBC boilers usually relies on addition of limestone, which is not used efficiently. Limestones with lower sulphation capacities are undesirable because they increase the raw materials and the residues requiring management. This increases operating costs and CO{sub 2} emissions. It is preferable to use less limestone or shells instead. The performance of adsorbents varies widely and depends mainly on their morphology and microstructure rather than on their chemical properties. Adsorption mechanisms are investigated. Fragmentation and attrition are important during calcination. Sulphation is affected by boiler size, configuration, operating conditions, oxidising and reducing zones, reactions with compounds in coal ash, and attrition. Preparation and handling of limestone at the plant is examined and care has to be taken to avoid moisture in all systems. Recently designed plants achieve an SO{sub 2} capture efficiency at or over 95% with addition of adsorbent at a Ca:S molar ratio of 2-2.5 depending on the sulphur content of the fuel and the reactivity of the adsorbent. Various methods of enhancing SO{sub 2} capture are reviewed. Sorbent reactivation by pressurised steam hydration or grinding/hydration appear to be most promising but are not yet used on full-scale CFBC. Fuels and operating conditions affect emissions control and the production of residues. The adsorbent requirement may be reduced by cofiring with low sulphur high calcium fuels and by optimising the furnace temperature for different fuels. The effect of sulphur capture on other emissions ie examined. NOx and N{sub 2}O emissions may be reduced by choice of fuels and adsorbent. An increase in CO{sub 2} emissions results from minimising use of limestone or by carbonization/calcination to capture CO{sub 2} before sulphation. 110 refs., 11 figs., 10 tab.

Non-linear optical studies of adsorbates: Spectroscopy and dynamics

Energy Technology Data Exchange (ETDEWEB)

Zhu, Xiangdong.

1989-08-01

In the first part of this thesis, we have established a systematic procedure to apply the surface optical second-harmonic generation (SHG) technique to study surface dynamics of adsorbates. In particular, we have developed a novel technique for studies of molecular surface diffusions. In this technique, the laser-induced desorption with two interfering laser beams is used to produce a monolayer grating of adsorbates. The monolayer grating is detected with diffractions of optical SHG. By monitoring the first-order second-harmonic diffraction, we can follow the time evolution of the grating modulation from which we are able to deduce the diffusion constant of the adsorbates on the surface. We have successfully applied this technique to investigate the surface diffusion of CO on Ni(111). The unique advantages of this novel technique will enable us to readily study anisotropy of a surface diffusion with variable grating orientation, and to investigate diffusion processes of a large dynamic range with variable grating spacings. In the second part of this work, we demonstrate that optical infrared-visible sum-frequency generation (SFG) from surfaces can be used as a viable surface vibrational spectroscopic technique. We have successfully recorded the first vibrational spectrum of a monolayer of adsorbates using optical infrared-visible SFG. The qualitative and quantitative correlation of optical SFG with infrared absorption and Raman scattering spectroscopies are examined and experimentally demonstrated. We have further investigated the possibility to use transient infrared-visible SFG to probe vibrational transients and ultrafast relaxations on surfaces. 146 refs.

Non-linear optical studies of adsorbates: Spectroscopy and dynamics

International Nuclear Information System (INIS)

Zhu, Xiangdong.

1989-08-01

In the first part of this thesis, we have established a systematic procedure to apply the surface optical second-harmonic generation (SHG) technique to study surface dynamics of adsorbates. In particular, we have developed a novel technique for studies of molecular surface diffusions. In this technique, the laser-induced desorption with two interfering laser beams is used to produce a monolayer grating of adsorbates. The monolayer grating is detected with diffractions of optical SHG. By monitoring the first-order second-harmonic diffraction, we can follow the time evolution of the grating modulation from which we are able to deduce the diffusion constant of the adsorbates on the surface. We have successfully applied this technique to investigate the surface diffusion of CO on Ni(111). The unique advantages of this novel technique will enable us to readily study anisotropy of a surface diffusion with variable grating orientation, and to investigate diffusion processes of a large dynamic range with variable grating spacings. In the second part of this work, we demonstrate that optical infrared-visible sum-frequency generation (SFG) from surfaces can be used as a viable surface vibrational spectroscopic technique. We have successfully recorded the first vibrational spectrum of a monolayer of adsorbates using optical infrared-visible SFG. The qualitative and quantitative correlation of optical SFG with infrared absorption and Raman scattering spectroscopies are examined and experimentally demonstrated. We have further investigated the possibility to use transient infrared-visible SFG to probe vibrational transients and ultrafast relaxations on surfaces. 146 refs

Adsorption of organic layers over electrodeposited magnetite (Fe3O4) thin films

International Nuclear Information System (INIS)

Cortes, M.; Gomez, E.; Sadler, J.; Valles, E.

2011-01-01

Research highlights: → Adherent low roughness magnetite films ranging from 80 nm to 3.75 μm-thick were electrodeposited on Au/glass substrates under galvanostatic control. → X-ray diffraction and magnetic measurements corroborates the purity of the electrodeposited magnetite. → Both dodecanethiol and oleic acid are shown to adsorb on the magnetite prepared at low temperature, significantly inducing the hydrophobicity of the surface. → Contact angle and voltammetric measurements, as well as XPS confirm the monolayers formation. - Abstract: The formation of monolayers of two organic compounds (oleic acid and dodecanethiol) over magnetite films was studied. Magnetite films ranging from 80 nm to 3.75 μm-thick were electrodeposited on Au on glass substrates under galvanostatic control, with deposition parameters optimized for minimum surface roughness. Films were characterised by SEM and AFM, showing granular deposits with a low rms roughness of 5-40 nm measured over an area of 1 μm 2 . The growth rate was estimated by measuring cross-sections of the thin films. Pure magnetite with an fcc structure is observed in XRD diffractograms. The adsorption of both oleic acid and dodecanethiol on the magnetite films was tested by immersing them in ethanol solutions containing the organic molecules, for different deposition time, temperature and cleaning procedure. Monolayer formation in both cases was studied by contact angle and voltammetric measurements, as well as XPS.

Reaction of Tri-methylaluminum on Si (001) Surface for Initial Aluminum Oxide Thin-Film Growth

International Nuclear Information System (INIS)

Kim, Dae Hee; Kim, Dae Hyun; Jeong, Yong Chan; Seo, Hwa Il; Kim, Yeong Cheol

2010-01-01

We studied the reaction of tri-methylaluminum (TMA) on hydroxyl (OH)-terminated Si (001) surfaces for the initial growth of aluminum oxide thin-films using density functional theory. TMA was adsorbed on the oxygen atom of OH due to the oxygen atom's lone pair electrons. The adsorbed TMA reacted with the hydrogen atom of OH to produce a di-methylaluminum group (DMA) and methane with an energy barrier of 0.50 eV. Low energy barriers in the range of 0 - 0.11 eV were required for DMA migration to the inter-dimer, intra-dimer, and inter-row sites on the surface. A unimethylaluminum group (UMA) was generated at each site with low energy barriers in the range of 0.21 - 0.25 eV. Among the three sites, the inter-dimer site was the most probable for UMA formation

Hydrogen molecule on lithium adsorbed graphene: A DFT study

International Nuclear Information System (INIS)

Kaur, Gagandeep; Gupta, Shuchi; Gaganpreet; Dharamvir, Keya

2016-01-01

Electronic structure calculations for the adsorption of molecular hydrogen on lithium (Li) decorated and pristine graphene have been studied systematically using SIESTA code [1] within the framework of the first-principle DFT under the Perdew-Burke-Ernzerhof (PBE) form of the generalized gradient approximation (GGA)[2], including spin polarization. The energy of adsorption of hydrogen molecule on graphene is always enhanced by the presence of co-adsorbed lithium. The most efficient adsorption configuration is when H 2 is lying parallel to lithium adsorbed graphene which is in contrast to its adsorption on pristine graphene (PG) where it prefers perpendicular orientation.

Towards Biomimicking Wood: Fabricated Free-standing Films of Nanocellulose, Lignin, and a Synthetic Polycation

Science.gov (United States)

Pillai, Karthik; Navarro Arzate, Fernando; Zhang, Wei; Renneckar, Scott

2014-01-01

Woody materials are comprised of plant cell walls that contain a layered secondary cell wall composed of structural polymers of polysaccharides and lignin. Layer-by-layer (LbL) assembly process which relies on the assembly of oppositely charged molecules from aqueous solutions was used to build a freestanding composite film of isolated wood polymers of lignin and oxidized nanofibril cellulose (NFC). To facilitate the assembly of these negatively charged polymers, a positively charged polyelectrolyte, poly(diallyldimethylammomium chloride) (PDDA), was used as a linking layer to create this simplified model cell wall. The layered adsorption process was studied quantitatively using quartz crystal microbalance with dissipation monitoring (QCM-D) and ellipsometry. The results showed that layer mass/thickness per adsorbed layer increased as a function of total number of layers. The surface coverage of the adsorbed layers was studied with atomic force microscopy (AFM). Complete coverage of the surface with lignin in all the deposition cycles was found for the system, however, surface coverage by NFC increased with the number of layers. The adsorption process was carried out for 250 cycles (500 bilayers) on a cellulose acetate (CA) substrate. Transparent free-standing LBL assembled nanocomposite films were obtained when the CA substrate was later dissolved in acetone. Scanning electron microscopy (SEM) of the fractured cross-sections showed a lamellar structure, and the thickness per adsorption cycle (PDDA-Lignin-PDDA-NC) was estimated to be 17 nm for two different lignin types used in the study. The data indicates a film with highly controlled architecture where nanocellulose and lignin are spatially deposited on the nanoscale (a polymer-polymer nanocomposites), similar to what is observed in the native cell wall. PMID:24961302

Air-stable n-type doping of graphene from overlying Si3N4 film

International Nuclear Information System (INIS)

Wang, Zegao; Li, Pingjian; Chen, Yuanfu; Liu, Jingbo; Qi, Fei; Tian, Hongjun; Zheng, Binjie; Zhou, Jinhao

2014-01-01

In this study, we report a facile method to obtain air-stable n-type graphene by plasma-enhanced chemical vapor depositing Si 3 N 4 film on the surface of graphene. We have demonstrated that the overlying Si 3 N 4 film can not only act as the penetration-barrier against H 2 O and O 2 adsorbed on the graphene surface, but also cause an effective n-type doping due to the amine groups at the interface of graphene/Si 3 N 4 . Furthermore, the studies reveal that the Dirac point of graphene can be modulated by the thickness of Si 3 N 4 film, which is due to competing effects of Si 3 N 4 -induced doping (n-type) and penetrating H 2 O (O 2 )-induced doping (p-type). We expect this method to be used for obtaining stable n-type graphene field-effect transistors in air, which will be widely used in graphene electronic devices.

In situ evaluation of density, viscosity, and thickness of adsorbed soft layers by combined surface acoustic wave and surface plasmon resonance.

Science.gov (United States)

Francis, Laurent A; Friedt, Jean-Michel; Zhou, Cheng; Bertrand, Patrick

2006-06-15

We show the theoretical and experimental combination of acoustic and optical methods for the in situ quantitative evaluation of the density, the viscosity, and the thickness of soft layers adsorbed on chemically tailored metal surfaces. For the highest sensitivity and an operation in liquids, a Love mode surface acoustic wave (SAW) sensor with a hydrophobized gold-coated sensing area is the acoustic method, while surface plasmon resonance (SPR) on the same gold surface as the optical method is monitored simultaneously in a single setup for the real-time and label-free measurement of the parameters of adsorbed soft layers, which means for layers with a predominant viscous behavior. A general mathematical modeling in equivalent viscoelastic transmission lines is presented to determine the correlation between experimental SAW signal shifts and the waveguide structure including the presence of the adsorbed layer and the supporting liquid from which it segregates. A methodology is presented to identify from SAW and SPR simulations the parameters representatives of the soft layer. During the absorption of a soft layer, thickness or viscosity changes are observed in the experimental ratio of the SAW signal attenuation to the SAW signal phase and are correlated with the theoretical model. As application example, the simulation method is applied to study the thermal behavior of physisorbed PNIPAAm, a polymer whose conformation is sensitive to temperature, under a cycling variation of temperature between 20 and 40 degrees C. Under the assumption of the bulk density and the bulk refractive index of PNIPAAm, thickness and viscosity of the film are obtained from simulations; the viscosity is correlated to the solvent content of the physisorbed layer.

Infrared spectroscopic and voltammetric study of adsorbed CO on stepped surfaces of copper monocrystalline electrodes

International Nuclear Information System (INIS)

Koga, O.; Teruya, S.; Matsuda, K.; Minami, M.; Hoshi, N.; Hori, Y.

2005-01-01

Voltammetric and infrared (IR) spectroscopic measurements were carried out to study adsorbed CO on two series of copper single crystal electrodes n(111)-(111) and n(111)-(100) in 0.1M KH 2 PO 4 +0.1M K 2 HPO 4 at 0 o C. Reversible voltammetric waves were observed below -0.55V versus SHE for adsorption of CO which displaces preadsorbed phosphate anions. The electric charge of the redox waves is proportional to the step atom density for both single crystal series. This fact indicates that phosphate anions are specifically adsorbed on the step sites below -0.55V versus SHE. Voltammetric measurements indicated that (111) terrace of Cu is covered with adsorbed CO below -0.5V versus SHE. Nevertheless, no IR absorption band of adsorbed CO is detected from (111) terrace. Presence of adsorbed CO on (111) terrace is presumed which is not visible by the potential difference spectroscopy used in the present work. IR spectroscopic measurements showed that CO is reversibly adsorbed with an on-top manner on copper single crystal electrodes of n(111)-(111) and n(111)-(100) with approximately same wavenumber of C?O stretching vibration of 2070cm -1 . The IR band intensity is proportional to the step atom density. Thus CO is adsorbed on (111) or (100) steps on the single crystal surfaces. An analysis of the IR band intensity suggested that one CO molecule is adsorbed on every two or more Cu step atom of the monocrystalline surface. The spectroscopic data were compared with those reported for uhv system. The C-O stretching wavenumber of adsorbed CO in the electrode-electrolyte system is 30-40cm -1 lower than those in uhv system

Electrocatalytic properties of monometallic and bimetallic nanoparticles-incorporated polypyrrole films for electro-oxidation of methanol

Energy Technology Data Exchange (ETDEWEB)

Selvaraj, V.; Alagar, M. [Department of Chemical Engineering, Alagappa College of Technology, Anna University, Chennai 600025 (India); Hamerton, I. [Chemistry Division, School of Biomedical and Molecular Sciences, University of Surrey, Guildford, Surrey GU2 7XH (United Kingdom)

2006-10-06

Oxidative electrochemical polymerization of pyrrole at indium-doped tin oxide (ITO) is accomplished from a neat monomer solution with a supporting electrolyte (0.3M n-tetrabutyl ammonium tetrafluoroborate) by multiple-scan cyclic voltammetry. Polypyrrole (Ppy) films containing nanometer-sized platinum and Pt/Pd bimetallic particles are electro-synthesized on ITO glass plates by voltammetric cycling between -0.1 and +1V (versus Ag/AgCl/3M NaCl). The electrocatalytic oxidation of methanol on the nanoparticle-modified polypyrrole films is studied by means of electrochemical techniques. The modified electrode exhibits significant eletrocatalytic activity for methanol oxidation. The enhanced electrocatalytic activities may be due to the uniform dispersion of nanoparticles in the polypyrrole film and a synergistic effect of the highly-dispersed metal particles so that the polypyrrole film reduces electrode poisoning by adsorbed CO species. The monometallic (Pt) and bimetallic (Pt/Pd) nanoparticles are uniformly dispersed in polypyrrole matrixes, as confirmed by scanning electron microscopic and atomic force microscopic analysis. Energy dispersive X-ray analysis is used to characterize the composition of metal present in the nanoparticle-modified electrodes. (author)

Architecture effects of glucose oxidase/Au nanoparticle composite Langmuir-Blodgett films on glucose sensing performance

Science.gov (United States)

Wang, Ke-Hsuan; Wu, Jau-Yann; Chen, Liang-Huei; Lee, Yuh-Lang

2016-03-01

The Langmuir-Blodgett (LB) deposition technique is employed to prepare nano-composite films consisting of glucose oxidase (GOx) and gold nanoparticles (AuNPs) for glucose sensing applications. The GOx and AuNPs are co-adsorbed from an aqueous solution onto an air/liquid interface in the presence of an octadecylamine (ODA) template monolayer, forming a mixed (GOx-AuNP) monolayer. Alternatively, a composite film with a cascade architecture (AuNP/GOx) is also prepared by sequentially depositing monolayers of AuNPs and GOx. The architecture effects of the composite LB films on the glucose sensing are studied. The results show that the presence of AuNPs in the co-adsorption system does not affect the adsorption amount and preferred conformation (α-helix) of GOx. Furthermore, the incorporation of AuNPs in both composite films can significantly improve the sensing performance. However, the enhancement effects of the AuNPs in the two architectures are distinct. The major effect of the AuNPs is on the facilitation of charge-transfer in the (GOx-AuNP) film, but on the increase of catalytic activity in the (AuNP/GOx) one. Therefore, the sensing performance can be greatly improved by utilizing a film combining both architectures (AuNP/GOx-AuNP).

Transport of significant metals recovered in real sea experiment of adsorbents

International Nuclear Information System (INIS)

Takeda, Hayato; Tamada, Masao; Kasai, Noboru; Katakai, Akio; Hasegawa, Shin; Seko, Noriaki; Sugo, Takanobu; Kawabata, Yukiya

2001-10-01

Real sea experiment for the recovery of significant metals such as uranium and vanadium which dissolved in seawater with extremely low concentration has been carried out at the offing of Mutsu establishment to evaluate the adsorption performance of adsorbent synthesized by radiation-induced graft-polymerization. The significant metals of uranium and vanadium eluted from the adsorbent which was soaked in the real sea were adsorbed onto the conventional chelate resin. The chelate resin which adsorbed the metals was packed in a plastic (PVC) column and further put in a cylindrical stainless transport container. This container was transported to the facility for separation and purification by a truck for the exclusive loading. Then the recovers metals were purified there. The recovered metals contained the uranium of 150g (1.92 MBq) and less in one recovery experiment. The maximum concentration is 60 Bq/g when the uranium is adsorbed on the chelate resin. Transport of recovered metals can be treated as general substance since these amount and concentration are out of legal control. However, the recovered metals were transported in conformity to L type Transport as a voluntary regulation. Though there is no requirements of structural strength for L type package legally, the structural strength of container was designed on that of IP-2 type which is higher transport grade than L type to take its safety measure. Its strength analysis proved the safety under general transport process. The transport was based on the plan made in advance. (author)

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

International Nuclear Information System (INIS)

Hirotsu, Takahiro; Fujii, Ayako; Sakane, Kohji; Katoh, Shunsaku; Sugasaka, Kazuhiko

1984-01-01

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)

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

International Nuclear Information System (INIS)

Hirotsu, Takahiro; Fujii, Ayako; Sakane, Kohji; Katoh, Shunsaku; Sugasaka, Kazuhiko

1983-01-01

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)

Application of nanoporous silicas as adsorbents for chlorinated aromatic compounds. A comparative study

Energy Technology Data Exchange (ETDEWEB)

Moritz, Michał, E-mail: michal.moritz@put.poznan.pl [Poznan University of Technology, Faculty of Chemical Technology, Institute of Chemistry and Technical Electrochemistry, Piotrowo 3, 60-965 Poznań (Poland); Adam Mickiewicz University, Faculty of Chemistry, Umultowska 89b, 61-614 Poznań (Poland); Geszke-Moritz, Małgorzata, E-mail: Malgorzata.Geszke-Moritz@amu.edu.pl [NanoBioMedical Centre, Adam Mickiewicz University, Umultowska 85, 61-614 Poznań (Poland)

2014-08-01

The removal of two selected environmental pollutants such as 2,4-dichlorophenoxyacetic acid (2,4-D) and Triclosan (TC) was examined by adsorption experiments on the modified SBA-15 and MCF mesoporous silicas. Mesoporous adsorbents were modified by a grafting process with (3-aminopropyl)triethoxysilane (APTES) and 1-[3-(trimethoxysilyl)propyl]urea (TMSPU). Mesoporous materials were synthesized and characterized by N{sub 2} adsorption–desorption experiment, transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FT-IR), elemental analysis and adsorption studies. The results show that both APTES-functionalized SBA-15 and MCF nanoporous carriers are potentially good adsorbents for the removal of 2,4-D in a wide range of concentrations from 0.1 to 4 mg/cm{sup 3}. Maximum adsorption capacity of as-modified adsorbents for 2,4-D estimated from the Langmuir model was ∼ 280 mg/g. The ionic interaction between the adsorbent and 2,4-D seems to play a key role in the adsorption process of the pollutant on APTES-modified siliceous matrices. The efficiency of TC sorption onto all prepared mesoporous adsorbents was significantly lower as compared to the entrapment of 2,4-D. Experimental data were best fitted by the Langmuir isotherm model. The results of this study suggest that mesoporous silica-based materials are promising adsorbents for the removal of selected organic pollutants. - Graphical abstract: Adsorption of 2,4-dichlorophenoxyacetic acid and Triclosan inside 3-amino-functionalized mesoporous channel.

Interstitial and adsorbed phosphates in shelf sediments off Visakhapatnam, east coast of India

Digital Repository Service at National Institute of Oceanography (India)

Sarma; Raju, G.R.K.

Spatial distribution of interstitial and adsorbed phosphates in the shelf sediments shows an increasing trend with distance from coastal to inshore region. Maximum concentration ranges of interstitial and adsorbed phosphates are 16-19 and 40-50 mu g...

Role of adsorbates on current fluctuations in DC field emission

International Nuclear Information System (INIS)

Luong, M.; Bonin, B.; Long, H.; Safa, H.

1996-01-01

Field emission experiments in DC regime usually show important current fluctuations for a fixed electric field. These fluctuations are attributed to adsorbed layers (molecules or atoms), liable to affect the work function, height and shape of the potential barrier binding the electron in the metal. The role of these adsorbed species is investigated by showing that the field emission from a well desorbed sample is stable and reproducible and by comparing the emission from the same sample before and after desorption. (author)

Catalytic isotope exchange reaction between deuterium gas and water pre-adsorbed on platinum/alumina

International Nuclear Information System (INIS)

Iida, Itsuo; Kato, Junko; Tamaru, Kenzi.

1976-01-01

The catalytic isotope exchange reaction between deuterium gas and the water pre-adsorbed on Pt/Al 2 O 3 was studied. At reaction temperatures above 273 K, the exchange rate was proportional to the deuterium pressure and independent of the amount of adsorbed water, which suggests that the rate determining step is the supply of deuterium from the gas phase. Its apparent activation energy was 38 kJ mol -1 . Below freezing point of water, the kinetic behaviour was different from that above freezing point. At higher deuterium pressures the rate dropped abruptly at 273 K. Below the temperature the apparent activation energy was 54 kJ mol -1 and the exchange rate depended not on the deuterium pressure but on the amount of the pre-adsorbed water. At lower pressures, however, the kinetic behaviour was the same as the above 273 K, till the rate of the supply of deuterium from the gas phase exceeded the supply of hydrogen from adsorbed water to platinum surface. These results suggest that below 273 K the supply of hydrogen is markedly retarded, the state of the adsorbed water differing from that above 273 K. It was also demonstrated that when the adsorbed water is in the state of capillary condensation, the exchange rate becomes very small. (auth.)

Preparation and Evaluation of Adsorbents from Coal and Irvingia gabonensis Seed Shell

Science.gov (United States)

Ezeokonkwo, Mercy A.; Ofor, Okechukwu F.; Ani, Julius U.