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1

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

UK PubMed Central (United Kingdom)

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

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

2012-11-01

2

Development of functionally graded anti-oxidation coatings for carbon/carbon composites  

Energy Technology Data Exchange (ETDEWEB)

The concept of functionally graded materials (FGMs) was originated in the research field of thermal barrier coatings. Continuous changes in the composition, grain size, porosity, etc., of these materials result in gradients in such properties as mechanical strength and thermal conductivity. In recent years, functionally graded structural composite materials have received increased attention as promising candidate materials to exhibit better mechanical and functional properties than homogeneous materials or simple composite materials. Therefore the research area of FGMs has been expending in the development of various structural and functional materials, such as cutting tools, photonic crystals, dielectric and piezoelectric ceramics, thermoelectric semiconductors, and biomaterials. We have developed functionally graded structural ceramic/metal composite materials for relaxation of thermal stress, functionally graded anti-oxidation coatings for carbon/carbon composites, and functionally graded dielectric ceramic composites to develop advanced dielectric ceramics with flat characteristics of dielectric constant in a wide temperature range. This paper introduces functionally graded coatings for C/C composites with superior oxidation resistance at high temperatures. (orig.)

Jeon, J.H. [Dept. of Materials Technology, Korea Inst. of Machinery and Materials, Changwon (Korea); Fang Hai-Tao; Lai Zhong-Hong; Yin Zhong-Da [Materials Science and Engineering School, Harbin Inst. of Tech., Harbin (China)

2005-07-01

3

Adsorption Characterization of Strontium on PAN/Zeolite Composite Adsorbent  

Digital Repository Infrastructure Vision for European Research (DRIVER)

This work reports the adsorption of strontium from aqueous solutions onto PAN/zeolite composite. The strontium adsorption on the composite adsorbent was studied as a function of initial strontium concentration, pH of the solution, contact time and temperature. Adsorption isotherms like Langmuir, Fre...

Sabriye Yusan; Sema Erenturk

4

Isothermal composite adsorbent. Part I: Thermal characterisation  

Energy Technology Data Exchange (ETDEWEB)

Adsorption and desorption are respectively exo and endothermic phenomena leading to significant temperature changes in adsorption columns. Enhanced efficiency of a sorption process could be obtained under isothermal conditions, either for gas storage, purification or separation applications. The heat transfer within the adsorbent beds can be managed in situ, using thermal energy storage material: a phase change materials (PCM) for example. The thermal behaviour of a mixture of activated carbon and PCM during CO{sub 2} adsorption has been studied. The thermal characteristics of the involved materials have been determined and experiments carried out to highlight the positive effect of the PCM to reduce the CO{sub 2} adsorption heat effects on an activated carbon bed. Calorimetry was the technique used for all the thermal characterisations. It appears that the heat effects induced by CO{sub 2} adsorption are reduced by the presence of the PCM together with the adsorbent. The endothermic effect of fusion balances the heat effect of adsorption and significantly reduces the temperature changes.

Meljac, L. [PROMES-CNRS UPR 8521, Universite de Perpignan UPVD, Tecnosud, Rambla de la Thermodynamique, 66100 Perpignan (France); Goetz, V. [PROMES-CNRS UPR 8521, Universite de Perpignan UPVD, Tecnosud, Rambla de la Thermodynamique, 66100 Perpignan (France)]. E-mail: goetz@univ-perp.fr; Py, X. [PROMES-CNRS UPR 8521, Universite de Perpignan UPVD, Tecnosud, Rambla de la Thermodynamique, 66100 Perpignan (France)

2007-04-15

5

REVIEW: USE of COMPOSITE ADSORBENTS in ADSORPTION REFRIGERATION  

Directory of Open Access Journals (Sweden)

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

Vaibhav N. Deshmukh; Satishchandra V. Joshi

2012-01-01

6

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

UK PubMed Central (United Kingdom)

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

Nie R; Zhu F; Shen L; Chen Z

2010-04-01

7

Adsorption of lead ions on composite biopolymer adsorbent  

Energy Technology Data Exchange (ETDEWEB)

A fundamental study about the application of biopolymers to the recovery of lead from dilute solution was carried out. A membranous composite biopolymer adsorbent containing two kind of biopolymers, alginic acid (AA) and humic acid (HA), was prepared. HA, which has high solubility in water, was almost completely immobilized in the adsorbent by a combination of calcium alginate gel and activated carbon powder. A general model for complexation between divalent metal ions and acidic sites on biopolymers was applied to explain the adsorption mechanism of lead on the adsorbent (HA-M). The results showed that the complexation constants and the complexation capacities of lead-AA and lead-HA systems were scarcely influenced by immobilization.

Seki, Hideshi; Suzuki, Akira [Hokkaido Univ., Hakodate (Japan)

1996-04-01

8

Adsorbent  

International Nuclear Information System (INIS)

An adsorbent is prepared by mixing at least one member selected from a first group consisting of metal oxides and metal compounds capable of partly or wholly forming metal oxides when heated in an oxygen-containing atmosphere with at least one member selected from a second group consisting of metal sulfides and metal compounds capable of partly or wholly forming metal sulfides when heated in an oxygen-containing atmosphere, and heating the mixture in an oxygen-containing atmosphere. This adsorbent has a remarkably high capacity of adsorbing heavy metals such as uranium. This adsorbent, which is easy to handle and can be produced with ease, enables recovery of uranium from sea water on an industrial scale because of its remarkably high adsorbing ability. (author)

1989-01-01

9

Adsorption Characterization of Strontium on PAN/Zeolite Composite Adsorbent  

Directory of Open Access Journals (Sweden)

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

Sabriye Yusan; Sema Erenturk

2011-01-01

10

Electrochemical niobium oxide coating in molten NaNO3-KNO3  

International Nuclear Information System (INIS)

[en] Kinetics of anodic oxide film growth on niobium in molten NaNO3-KNO3 (50 mol %) is studied in galvanostatic and potentiostatic conditions. Basic kinetic parameters of the oxide-coating process are determined. Chemical composition of the oxide coatings is established

1999-01-01

11

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

Energy Technology Data Exchange (ETDEWEB)

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

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

2011-10-01

12

Method of forming oxide coatings  

Energy Technology Data Exchange (ETDEWEB)

This invention is concerned with an improved plating process for covering a substrate with a black metal oxide film. The invention is particularly directed to making a heating panel for a solar collector. A compound is electrodeposited from an aqueous solution containing cobalt metal salts onto a metal substrate. This compound is converted during plating into a black, highly absorbing oxide coating which contains hydrated oxides. This is achieved by the inclusion of an oxidizing agent in the plating bath. The inclusion of an oxidizing agent in the plating bath is contrary to standard electroplating practice. The hydrated oxides are converted to oxides by treatment in a hot bath, such as boiling water. An oxidizing agent may be added to the hot liquid treating bath.

Mcdonald, G.E.

1981-06-01

13

Synthesis of composite by application of mixed Fe, Mg (hydr)oxides coatings onto bentonite--a use for the removal of Pb(II) from water.  

UK PubMed Central (United Kingdom)

The procedure for obtaining a bentonite based composite involves the application of mixed Fe and Mg hydroxides coatings onto bentonite particles in aqueous suspension and subsequent thermal treatment of the solid phase at 498 K. Structural and textural modifications of montmorillonite which occurred during the synthesis of composite were confirmed by XRD technique and N(2) adsorption at 77K. The composite structure was found to be less ordered, while its specific surface area was about two times higher than the specific surface area of the starting/native bentonite. The effectiveness of the composite in Pb(II) removal from aqueous solutions at different initial concentrations, pH and ionic strengths of the solutions was examined. The equilibrium adsorption data were analyzed using three widely applied isotherms: Langmuir, Freundlich and Dubinin-Radushkevich. The composite effectively removes both ionic and colloidal forms of Pb(II) from water and the maximum adsorption capacity obtained from the Langmuir equation was 95.88 mg/g. The main mechanisms of Pb(II) removal at low pH values were ion-exchange and outer-sphere surface complexation.

Ran?elovi? M; Purenovi? M; Zarubica A; Purenovi? J; Matovi? B; Mom?ilovi? M

2012-01-01

14

Composite adsorbent of CaCl{sub 2} and expanded graphite for adsorption ice maker on fishing boats  

Energy Technology Data Exchange (ETDEWEB)

Adsorption performances and thermal conductivity were tested for three types of adsorbent: Pure CaCl{sub 2} powder, simple composite adsorbent and consolidated composite adsorbent. The simple composite adsorbents show better adsorption performance because the additive of expanded graphite in CaCl{sub 2} powder has restrained the agglomeration phenomenon in adsorption process and improved the adsorption performance of CaCl{sub 2}. The consolidated composite adsorbent are suitable to be used as adsorbent for ice maker on fishing boats because they have higher thermal conductivity, larger volumetric cooling capacity, higher SCP values and better anti-sway performance than simple composite adsorbents. Thermal conductivity of the consolidated composite adsorbent is 6.5-9.8Wm{sup -1}K{sup -1} depending on the molding pressure, ranging from 5 to 15MPa, which is about 32 times higher than the thermal conductivity of CaCl{sub 2} powder. The volumetric cooling capacity of consolidated composite adsorbent is about 52% higher than the best result obtained for CaCl{sub 2} at the evaporating temperature of -10{sup o}C. The SCP of the consolidated adsorbent increases of about 353% than CaCl{sub 2} powder from simulation results at T{sub ad}=30{sup o}C and T{sub ev}=-10{sup o}C. The consolidated composite adsorbents have good anti-sway performance and they are not easy to be scattered out when the fishing boats sway on the sea. (author)

Wang, K.; Wu, J.Y.; Wang, R.Z.; Wang, L.W. [Institute of Refrigeration and Cryogenics, Shanghai Jiao Tong University, Shanghai 200030 (China)

2006-03-15

15

Preparation and Property of SiC/(ZrB2-SiC/SiC)4 Anti-oxidation Coatings for Cf/SiC Composites  

Directory of Open Access Journals (Sweden)

Full Text Available A SiC/(ZrB2-SiC/SiC)4 coating was prepared by slurry painting and pulse CVD. The composition and structure of the coating were studied by using XRD,SEM and EDS analysis, then the anti-oxidation property of the coating was investigated. The results show that the thickness of obtained coating is about 100¦?, ZrB2-SiC layer and Pulse CVD SiC layer are bonded to each other alternately. After oxidation at 1500¡?n air for 25h, the weight loss of the Pulse CVD coating is 5.1%, while weight gain of the SiC/(ZrB2-SiC/SiC)4 coating is about 2.5%. The SiC/(ZrB2-SiC/SiC)4 coating shows excellent antiª²oxidation property.

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

2009-01-01

16

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

Energy Technology Data Exchange (ETDEWEB)

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

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

1996-12-01

17

Ceramic oxide coatings for the corrosion protection of silicon carbide  

Energy Technology Data Exchange (ETDEWEB)

Silicon carbide is currently used as a structural material for heat exchanger tubes and related applications because of its excellent thermal properties and oxidation resistance. Silicon carbide suffers corrosion degradation, however, in the aggressive furnace environments of industrial processes for aluminum remelting, advanced glass melting, and waste incineration. Adherent ceramic oxide coatings developed at Solar Turbines Incorporated, with the support of the Gas Research Institute, have been shown to afford corrosion protection to silicon carbide in a simulated aluminum remelt furnace environment as well as in laboratory-type corrosion testing. The coatings are also protective to silicon carbide-based ceramic matrix composites.

Roode, M. van; Price, J.R. (Solar Turbines Incorporated, San Diego, CA (United States)); Stala, C. (Salomon Brothers, New York, NY (United States))

1993-01-01

18

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

Directory of Open Access Journals (Sweden)

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

DEYI ZHANG; YING MA; HUIXIA FENG; YUAN HAO

2012-01-01

19

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

Energy Technology Data Exchange (ETDEWEB)

A measurement of moisture uptake curves in silica gel-calcium composite adsorbents is performed by using the thermal gravimetrical method in a relative vapor pressure range from 0.5 to 0.9 at different temperature levels of 25, 35 and 45 deg. C, respectively. Also, dynamic adsorption curves individually corresponding to the temperature and relative pressure conditions of (25 deg. C, 0.7) (35 deg. C, 0.7) and (35 deg. C, 0.5) have been measured. This experimental study shows that the sorption rate is highest for non-impregnated macroporous silica gel; however, the same silica gel impregnated with calcium chloride has a much greater final water loading. This confirms that composite adsorbents result in a better adsorption performance compared with non-impregnated silica gel, leading to a trade off in finalizing the content of CaCl{sub 2} in the composite. Through theoretical analysis on the experimental data, it is found that the saturated adsorption data can be well fitted by the FHH model and the dynamic adsorption data well fitted by the Crank diffusion model, simultaneously yielding the effective solid side mass diffusivities. A comparison with these obtained diffusion coefficients further supports that the mass diffusivity in the composite adsorbent also increases with an increase in temperature, as well as in humidity, but drastically decreases due to the presence of salt inside the matrix pores compared with the non-impregnated host matrix.

Zhang, X.J. [Institute of Refrigeration and Cryogenics, Zhejiang University, Zheda Road 38, Hangzhou, Zhejiang 310027 (China)]. E-mail: xuejzhang@zju.edu.cn; Qiu, L.M. [Institute of Refrigeration and Cryogenics, Zhejiang University, Zheda Road 38, Hangzhou, Zhejiang 310027 (China)

2007-01-15

20

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

Energy Technology Data Exchange (ETDEWEB)

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

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

1999-01-01

 
 
 
 
21

Bio sorption process for uranium (VI) by using algae-yeast-silica gel composite adsorbent  

International Nuclear Information System (INIS)

Many yeast, algae, bacteria and various aquatic flora are known to be capable of concentrating metal species from dilute aqueous solution. Many researcher have found that non-living biomaterials can be used to accumulate metal ions from environment. In recent studies, mainly two process are used in biosorption experiments. These are the use of free cells and the use of immobilized cells on a solid support. A variety of inert supports have been used to immobilize biomaterials either by adsorption or physical entrapment. This uptake is often considerable and frequently selective, and occurs via a variety of mechanisms including active transport, ion exchange or complexation, and adsorption or inorganic precipitation. Biosorbent may be used as an ion exchange material. Adsorption occurs through interaction of the metal ions with functional groups that are found in the cell wall biopolymers of either living or dead organisms. In this study, the algae-yeast-silica gel composite adsorbent was tested for its ability to recover U(VI) from diluted aqueous solutions. Macro marine algae (Jania rubens.), yeast (Saccharomyces cerevisiae) and silica gel were used to prepare composite adsorbent. The ability of the composite biosorbent to adsorb uranium (VI) from aqueous solution has been studied at different optimized conditions of pH, concentration of U(VI), temperature, contact time and matrix ion effect was also investigated. The adsorption patterns of uranium on the composite biosorbent were investigated by the Langmuir, Freundlich and Dubinin-Radushkhevic isotherms. The thermodynamic parameters such as variation of enthalpy ?H, variation of entropy ?S and variation of Gibbs free energy ?G were calculated. The results suggested that the macro algae-yeast-silica gel composite sorbent is suitable as a new biosorbent material for removal of uranium ions from aqueous solutions.

2006-01-01

22

Electrochemical characteristics of Ru-Sn oxide-coated titanium anodes for chlor-alkali membrane electrolysis  

Energy Technology Data Exchange (ETDEWEB)

The relation between composition of the oxide phase and the electrochemical characteristics has been investigated for ruthenium-tin (Ru-Sn) oxide-coated titanium anodes prepared by a thermal decomposition method. The oxide phases of the coatings, analyzed by X-ray diffractometry, gave almost invariable rutile structures regardless of the Ru/Sn ratio. The electrochemical characteristics were measured for the anodes with various Ru/Sn ratios using a laboratory scale chlor-alkali membrane cell. The electrochemical performance of the Ru/Sn oxide-coated anodes depended intensively on the oxide composition of the coating. 6 refs., 6 figs.

Nakajima, Y.; Nakamatsu, S.; Shimamune, T. [Permelec Electrode Ltd., Kanagawa (Japan); Matsuda, Y. [Yamaguchi University, Yamaguchi (Japan). Faculty of Engineering

1995-11-05

23

Controlled microcstructure oxide coating for chemical sensors  

Energy Technology Data Exchange (ETDEWEB)

We have investigated the use of porous oxide coatings, formed using sol-gel chemistry routes, as the discriminating elements of acoustic wave (AW) chemical sensors. These coatings provide several unique advantages: durability, high adsorption capacity based on large surface areas, and chemical selectivity based on both molecular size and chemical interactions. The porosity of these coatings is determined by performing nitrogen adsorption isotherms using the AW device response to monitor the uptake of nitrogen at 77 K. The chemical sensitivity and selectivity obtained with this class of coatings will be demonstrated using several examples: hydrous titanate ion exchange coatings, zeolite/silicate microcomposite coatings, and surface modified silicate films. 16 refs., 3 figs., 1 tab.

Frye, G.C.; Brinker, C.J.; Ashley, C.S.; Martinez, S.L. (Sandia National Labs., Albuquerque, NM (USA)); Bein, T. (New Mexico Univ., Albuquerque, NM (USA). Dept. of Chemistry)

1990-01-01

24

Porosity in plasma electrolytic oxide coatings  

International Nuclear Information System (INIS)

Plasma electrolytic oxide coatings are generally assumed to be almost fully dense. However, evidence is presented here for the presence of sub-micrometre, surface-connected porosity in such coatings, on aluminium alloys, at levels of the order of 20%. This evidence comes from densitometry, mercury porosimetry, helium pycnometry, BET adsorption measurements and high-resolution scanning electron microscopy. The very fine scale of the porosity (pore diameter ?10 to 100 nm), coupled with severe difficulties in making unambiguous microstructural observations, may account for the failure to detect this feature previously. It is pointed out that various measured properties, such as Young's modulus and thermal conductivity, are consistent with the presence of these relatively high porosity levels. Various other observed characteristics can also be explained on this basis. Finally, a possible mechanistic origin for the porosity is proposed.

2006-01-01

25

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

Science.gov (United States)

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

Ceylan, Seyda; Odaba??, Mehmet

2013-01-10

26

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

UK PubMed Central (United Kingdom)

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

Ceylan S; Odaba?? M

2013-01-01

27

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

Directory of Open Access Journals (Sweden)

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

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

2012-01-01

28

Porous ceramic/agarose composite adsorbents for fast protein liquid chromatography.  

UK PubMed Central (United Kingdom)

Porous ceramic/agarose composite adsorbents were designed and prepared with silica ceramic beads and 4% agarose gel, and then functionalized with a special ligand carboxymethyl. A novel method was introduced to fabricating of the porous silica ceramic beads. The morphology of SEM shows a spherical shape and a porous structure of the ceramic beads. Nitrogen adsorption-desorption analysis gives an average pore size of 287.5 ?, a BET surface area of 29.33 m²/g and a porosity of 41.8%, respectively. Additionally, X-ray diffraction pattern indicates that the amorphous silica has been transformed into two crystal phases of quartz and cristobalite, leading to a porous and rigid skeleton and ensuring the application of the composite beads at high flow velocities. Lysozyme of hen egg-white with the activity of 12,700 U/mg was purified by the composite ion-exchanger in one step and the recovery and purification factor reaches 95.2% and 7.9, respectively.

Xia H; Jin X; Wu P; Zheng Z

2012-02-01

29

Densification of mixed-oxide coated silicon nitride powders  

Energy Technology Data Exchange (ETDEWEB)

Powder coating is being developed as a method of incorporating sintering additives into a ceramic powder. This procedure has been explored in the case of Si{sub 3}N{sub 4} powders coated with mixed oxide layers of MgO-Al{sub 2}O{sub 3}. Mixed oxide coatings have been deposited on the surface of silicon nitride powders, with the aim of simulating grain-boundary eutectic liquid compositions for the purpose of achieving low-temperature densification. The effectiveness of the powder coating technique has been evaluated by comparing the powder properties, densification behaviour, and microstructure of coated Si{sub 3}N{sub 4} powders with identical powders in which the additive oxide has been added in particulate form. It is concluded that the powder coating technique is an excellent method of homogeneously incorporating minor amounts of sintering additive into a powder. The coated powder exhibited improved homogeneity, and gave good green compact density, high green strength, and faster densification rate. Moreover, coated powders densified more easily by pressureless sintering and showed a more homogeneous microstructure and faster densification rates, compared with materials prepared using mixed oxide powders. (orig.) 8 refs.

Tatli, Z.; Thompson, D.P. [Newcastle upon Tyne Univ. (United Kingdom). Dept. of Mechanical Materials and Manufacture Engineering; Errington, R.J. [Dept. of Chemistry Univ. of Newcastle, Newcastle upon Tyne (United Kingdom)

1997-12-31

30

Exploring the coordination chemistry of MOF-graphite oxide composites and their applications as adsorbents.  

UK PubMed Central (United Kingdom)

Metal-organic frameworks (MOFs), besides being porous materials exhibit a very rich chemistry, which can be used for the synthesis of composites and/or the reactive adsorption of toxic gases. In this study, composites of MOFs (MOF-5, HKUST-1 or MIL-100(Fe)) and a graphitic compound (graphite or graphite oxide, GO) were synthesized and tested for the removal of NH(3), H(2)S and NO(2) under ambient conditions. The materials were characterized before and after exposure to the target gases by X-ray diffraction, thermogravimetric analysis, N(2) sorption measurement and FT-IR spectroscopy. The results indicate that strong chemical bonds exist between the MOF and GO as a result of the coordination between the GO oxygen groups and the MOFs' metallic centers. Depending on the structure of the MOF, such interactions induce the formation of a new pore space in the interface between the carbon layers and the MOF units, which enhances the physical adsorption capacity of the toxic gases. When unsaturated metallic sites are present in the MOFs, the target gases are also adsorbed via coordination to these centers. Further reaction with the framework leads to the formation of complexes. This is accompanied by the collapse of the MOF structure.

Petit C; Bandosz TJ

2012-04-01

31

Exploring the coordination chemistry of MOF-graphite oxide composites and their applications as adsorbents.  

Science.gov (United States)

Metal-organic frameworks (MOFs), besides being porous materials exhibit a very rich chemistry, which can be used for the synthesis of composites and/or the reactive adsorption of toxic gases. In this study, composites of MOFs (MOF-5, HKUST-1 or MIL-100(Fe)) and a graphitic compound (graphite or graphite oxide, GO) were synthesized and tested for the removal of NH(3), H(2)S and NO(2) under ambient conditions. The materials were characterized before and after exposure to the target gases by X-ray diffraction, thermogravimetric analysis, N(2) sorption measurement and FT-IR spectroscopy. The results indicate that strong chemical bonds exist between the MOF and GO as a result of the coordination between the GO oxygen groups and the MOFs' metallic centers. Depending on the structure of the MOF, such interactions induce the formation of a new pore space in the interface between the carbon layers and the MOF units, which enhances the physical adsorption capacity of the toxic gases. When unsaturated metallic sites are present in the MOFs, the target gases are also adsorbed via coordination to these centers. Further reaction with the framework leads to the formation of complexes. This is accompanied by the collapse of the MOF structure. PMID:22353854

Petit, Camille; Bandosz, Teresa J

2012-02-21

32

Kinetics and mechanism of arsenate removal by nanosized iron oxide-coated perlite.  

UK PubMed Central (United Kingdom)

This study discussed the adsorption kinetics of As(V) onto nanosized iron oxide-coated perlite. The effects of pH, initial concentration of As(V) and common anions on the adsorption efficiency were also investigated. It was observed that a 100% As(V) adsorption was achieved at pH value of 4-8 from the initial concentration containing 1.0 mg-As(V)L(-1) and the adsorption percentage depended on the initial concentration; the phosphate and silicate ions would not interfere with the adsorption efficiency. Furthermore, nanosized iron oxide-coated perlite (IOCP) has been shown to be an effective adsorbent for the removal of arsenate from water. The adsorption kinetics were studied using pseudo-first- and pseudo-second-order models, and the experimental data fitted well with the pseudo-second-order model. Moreover, it suggests that the Langmuir isotherm is more adequate than the Freundlich isotherm in simulating the adsorption isotherm of As(V). The adsorption rate constant is 44.84 L mg(-1) and the maximum adsorption capacity is 0.39 mg g(-1). These findings indicate that the adsorption property of IOCP gives the compound a great potential for applications in environmental remediation.

Mostafa MG; Chen YH; Jean JS; Liu CC; Lee YC

2011-03-01

33

Kinetics and mechanism of arsenate removal by nanosized iron oxide-coated perlite.  

Science.gov (United States)

This study discussed the adsorption kinetics of As(V) onto nanosized iron oxide-coated perlite. The effects of pH, initial concentration of As(V) and common anions on the adsorption efficiency were also investigated. It was observed that a 100% As(V) adsorption was achieved at pH value of 4-8 from the initial concentration containing 1.0 mg-As(V)L(-1) and the adsorption percentage depended on the initial concentration; the phosphate and silicate ions would not interfere with the adsorption efficiency. Furthermore, nanosized iron oxide-coated perlite (IOCP) has been shown to be an effective adsorbent for the removal of arsenate from water. The adsorption kinetics were studied using pseudo-first- and pseudo-second-order models, and the experimental data fitted well with the pseudo-second-order model. Moreover, it suggests that the Langmuir isotherm is more adequate than the Freundlich isotherm in simulating the adsorption isotherm of As(V). The adsorption rate constant is 44.84 L mg(-1) and the maximum adsorption capacity is 0.39 mg g(-1). These findings indicate that the adsorption property of IOCP gives the compound a great potential for applications in environmental remediation. PMID:21282000

Mostafa, M G; Chen, Yen-Hua; Jean, Jiin-Shuh; Liu, Chia-Chuan; Lee, Yao-Chang

2011-01-05

34

Cultured Primary Macrophage Activation by Lipopolysaccharide Depends on Adsorbed Protein Composition and Substrate Surface Chemistry.  

Science.gov (United States)

Recent efforts show that significantly reducing implant-adsorbed proteins does not avoid the foreign body response. Fluorinated surfaces are commonly used to passivate cell-mediated inflammatory responses to implanted materials but adsorb host proteins and facilitate the attachment and proliferation of macrophages. This study considers in vitro macrophage activation to fluorinated TeflonAF(®) compared to tissue-culture polystyrene using pre-adsorbed proteins (fibrinogen, BSA, collagen and elastin). Primary macrophage cultures adhere on all pre-adsorbed protein surfaces in a protein concentration-dependent manner and activate to the same extent after 72 h, regardless of surface chemistry. However, macrophages alter their cultured adherent morphology depending on which protein is pre-adsorbed to these surfaces. Macrophages cultured on TeflonAF(®) on all pre-adsorbed proteins produced overall higher levels of the pro-inflammatory cytokines - TNF-?, IL-6, IL-1? or MCP-1 - than those cultured on tissue-culture polystyrene and those cultured in serum-free media. However, at 72 h, macrophages adherent on BSA or fibrinogen pre-adsorbed surfaces failed to exhibit increased amounts of TNF-?, IL-6 or IL-1? on either TeflonAF(®) or TCPS, as well as MCP-1 on TCPS, in the presence of activating lipopolysaccharide. Different cell responses to pre-adsorbed proteins reflect substrate-specific regulation of macrophage cytokine secretion, indicative of LPS tolerance distinct from secondary macrophage cultures, and also distinct from macrophages adherent to surfaces in the absence of proteins. This result has bearing on connecting macrophage adhesion via adsorbed proteins on (fluorinated) biomaterials, and their resulting chronic activation that yields the FBR and possibly reduces effective macrophage clearance of microbes around implanted materials. PMID:21722418

Diekjürgen, Dorina; Astashkina, Anna; Grainger, David W; Holt, Dolly; Brooks, Amanda E

2011-06-28

35

Cultured Primary Macrophage Activation by Lipopolysaccharide Depends on Adsorbed Protein Composition and Substrate Surface Chemistry.  

UK PubMed Central (United Kingdom)

Recent efforts show that significantly reducing implant-adsorbed proteins does not avoid the foreign body response. Fluorinated surfaces are commonly used to passivate cell-mediated inflammatory responses to implanted materials but adsorb host proteins and facilitate the attachment and proliferation of macrophages. This study considers in vitro macrophage activation to fluorinated TeflonAF(®) compared to tissue-culture polystyrene using pre-adsorbed proteins (fibrinogen, BSA, collagen and elastin). Primary macrophage cultures adhere on all pre-adsorbed protein surfaces in a protein concentration-dependent manner and activate to the same extent after 72 h, regardless of surface chemistry. However, macrophages alter their cultured adherent morphology depending on which protein is pre-adsorbed to these surfaces. Macrophages cultured on TeflonAF(®) on all pre-adsorbed proteins produced overall higher levels of the pro-inflammatory cytokines - TNF-?, IL-6, IL-1? or MCP-1 - than those cultured on tissue-culture polystyrene and those cultured in serum-free media. However, at 72 h, macrophages adherent on BSA or fibrinogen pre-adsorbed surfaces failed to exhibit increased amounts of TNF-?, IL-6 or IL-1? on either TeflonAF(®) or TCPS, as well as MCP-1 on TCPS, in the presence of activating lipopolysaccharide. Different cell responses to pre-adsorbed proteins reflect substrate-specific regulation of macrophage cytokine secretion, indicative of LPS tolerance distinct from secondary macrophage cultures, and also distinct from macrophages adherent to surfaces in the absence of proteins. This result has bearing on connecting macrophage adhesion via adsorbed proteins on (fluorinated) biomaterials, and their resulting chronic activation that yields the FBR and possibly reduces effective macrophage clearance of microbes around implanted materials.

Diekjürgen D; Astashkina A; Grainger DW; Holt D; Brooks AE

2011-06-01

36

Decontamination of spent iron-oxide coated sand from filters used in arsenic removal.  

UK PubMed Central (United Kingdom)

Sand filters devised with iron-rich adsorbents are extensively promoted and deployed in the arsenic-prone south and south-east Asian countries (e.g., Bangladesh). The approach offers superior performance in removing arsenic while the spent sludge from the sand filters is an issue of concern due to the possibility of toxic releases after being discarded. In this work, a new technique is proposed for the treatment of spent iron-oxide coated sand (IOCS) from filters used in arsenic removal. Chelant-washing of the arsenic-loaded IOCS is combined with the solid phase extraction treatment to accomplish the objective. The unique point of the proposed process is the cost-effective scheme, which includes the option of recycling of the washing solvent beside the decontamination of the spent arsenic-rich sludge.

Rahman IM; Begum ZA; Sawai H; Maki T; Hasegawa H

2013-06-01

37

Sodium sulfur container with chromium/chromium oxide coating  

Energy Technology Data Exchange (ETDEWEB)

A coating of chromium/chromium oxide is disclosed for coating the surfaces of electrically conducting components of a sodium sulfur battery. This chromium/chromium oxide coating is placed on the surfaces of the electrically conducting components of the battery which are in contact with molten polysulfide and sulfur reactants during battery operation.

Ludwig, Frank A. (Irvine, CA); Higley, Lin R. (Santa Ana, CA)

1981-01-01

38

Electrochemical oxidation of ethanol at platinum oxide coated titanium anode  

Energy Technology Data Exchange (ETDEWEB)

Platinum oxide coated titanium anode was prepared. Electrooxidation of ethanol in 0.5 mol. dm/sup /minus/3/ sulfuric acid at these electrodes was studied using galvanostatic polarization, linear sweep voltammetry and chronopotentiometric techniques. Based on the data obtained, a mechanism is proposed for the electrooxidation of ethanol at these electrodes.

Asokan, K.; Krishnan, V.

1988-04-01

39

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

Science.gov (United States)

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

Bandosz, Teresa J; Block, Karin

2006-05-15

40

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

UK PubMed Central (United Kingdom)

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

Bandosz TJ; Block K

2006-05-01

 
 
 
 
41

Thermodynamic and kinetic studies of As(V) removal from water by zirconium oxide-coated marine sand.  

UK PubMed Central (United Kingdom)

Arsenic contamination of groundwater is a major threat to human beings globally. Among various methods available for arsenic removal, adsorption is fast, inexpensive, selective, accurate, reproducible and eco-friendly in nature. The present paper describes removal of arsenate from water on zirconium oxide-coated sand (novel adsorbent). In the present work, zirconium oxide-coated sand was prepared and characterised by infrared and X-ray diffraction techniques. Batch experiments were performed to optimise different adsorption parameters such as initial arsenate concentration (100-1,000 ?g/L), dose (1-8 g/L), pH of the solution (2-14), contact time (15-150 min.), and temperature (20, 30, 35 and 40 °C). The experimental data were analysed by Langmuir, Freundlich, Temkin and Dubinin-Radushkevich isotherm models. Furthermore, thermodynamic and kinetic parameters were evaluated to know the mode of adsorption between ZrOCMS and As(V). The maximum removal of arsenic, 97 %, was achieved at initial arsenic concentration of 200 ?g/L, after 75 min at dosage of 5.0 g/L, pH 7.0 and 27 ± 2 °C. For 600 ?g/L concentration, the maximum Langmuir monolayer adsorption capacity was found to be 270 ?g/g at 35 °C. Kinetic modelling data indicated that adsorption process followed pseudo-second-order kinetics. The mechanism is controlled by liquid film diffusion model. Thermodynamic parameter, ?H°, was -57.782, while the values of ?G° were -9.460, -12.183, -13.343 and -13.905 kJ/mol at 20, 30, 35 and 40 °C, respectively, suggesting exothermic and spontaneous nature of the process. The change in entropy, ?S°=?-0.23 kJ/mol indicated that the entropy decreased due to adsorption of arsenate ion onto the solid adsorbent. The results indicated that the reported zirconium oxide-coated marine sand (ZrOCMS) was good adsorbent with 97 % removal capacity at 200 ?g/L concentration. It is interesting to note that the permissible limit of arsenic as per World Health Organization is 10 ?g/L, and in real situation, this low concentration can be achieved through this adsorbent. Besides, the adsorption capacity showed that this adsorbent may be used for the removal of arsenic from any natural water resource.

Khan TA; Chaudhry SA; Ali I

2013-08-01

42

Antibacterial activity of zinc oxide-coated nanoporous alumina  

Energy Technology Data Exchange (ETDEWEB)

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

Skoog, S.A. [Joint Department of Biomedical Engineering, University of North Carolina and North Carolina State University, Box 7115, Raleigh, NC 27695-7115 (United States); Bayati, M.R. [Department of Materials Science and Engineering, North Carolina State University, Box 7907, Raleigh, NC 27695-7907 (United States); Petrochenko, P.E. [Joint Department of Biomedical Engineering, University of North Carolina and North Carolina State University, Box 7115, Raleigh, NC 27695-7115 (United States); Division of Biology, Office of Science and Engineering Laboratories, Center for Devices and Radiological Health, U.S. Food and Drug Administration, Silver Spring, MD 20993 (United States); Stafslien, S.; Daniels, J.; Cilz, N. [Center for Nanoscale Science and Engineering, North Dakota State University, 1805 Research Park Drive, Fargo, ND 58102 (United States); Comstock, D.J.; Elam, J.W. [Energy Systems Division, Argonne National Laboratory, Argonne, IL 60439 (United States); Narayan, R.J., E-mail: roger_narayan@msn.com [Joint Department of Biomedical Engineering, University of North Carolina and North Carolina State University, Box 7115, Raleigh, NC 27695-7115 (United States); Department of Materials Science and Engineering, North Carolina State University, Box 7907, Raleigh, NC 27695-7907 (United States)

2012-07-25

43

Review of structural influences on the laser damage thresholds of oxide coatings  

Energy Technology Data Exchange (ETDEWEB)

The laser damage thresholds (LDT) of optical coatings lie, as a rule, markedly below those of the respective bulk materials. This is due to diverse specific real structure properties with regard to composition, crystallography, microstructure and the physico-chemical structure of the interfaces. These properties depend in a highly complex and sensitive way on the substrate treatment, coating techniques and deposition conditions. With evaporated and sputtered oxide coatings as example, some correlations between structural thin film properties (e.g. crystallography, microstructure, anisotropy, chemical composition, defects) and the ultraviolet (248 nm) or near infrared (1064 nm) laser damage thresholds are discussed with concern to a further increase of the damage resistance. It is evident from data that an approach to the problem requires complex investigations of the technology-structure-properties relationships.

Hacker, E.; Lauth, H.; Weibbrodt, P. [JENOPTIK Laser, Optik, Systeme GmbH, Jena (Germany)

1996-12-31

44

On the composition of volatiles evolved during the production of carbon adsorbents from vegetable wastes  

Energy Technology Data Exchange (ETDEWEB)

Gas and liquid products evolved in the process of carbon adsorbent production by steam pyrolysis of apricot stones and coconut shells are investigated. The oils are separated by an extrographic procedure, and the obtained fractions are analysed by gas chromatography-mass spectrometry. The basic part of the identified compounds are derivatives of phenol, guaiacol, veratrol, syringol, resorcinol, free fatty acids and esters of fatty acids. The comparative study of the pyrolysis products of apricot stones and coconut shells reveals some differences, referring mainly to the lipid parts of the raw materials. 17 refs., 1 fig., 6 tabs.

Razvigorova, M.; Goranova, M.; Minkova, V.; Cerny, J. (Bulgarian Academy of Sciences, Sofia (Bulgaria). Inst. of Organic Chemistry with Center of Phytochemistry)

1994-11-01

45

Relationship between surface viscosity and surface composition of adsorbed surfactant films  

Energy Technology Data Exchange (ETDEWEB)

The single-bubble foaming technique was used to determine the surface excess concentrations of aqueous solutions of sodium lauryl sulfate (SLS) and lauryl alcohol (LOH). The excess concentrations of sodium lauryl sulfate-lauryl alcohol showed that lauryl alcohol is preferentially adsorbed at the surface, but only partially displaces sodium lauryl sulfate. This causes a higher total surface concentration and, consequently, a closer packing of surfactant molecules. The total surface excess concentration increases with an increase in the bulk concentration of the 2 surfactants until the critical micelle concentration (CMC) is reached. At concentrations exceeding the CMC, the surface excess concentration of LOH remains virtually constant, while that of SLS declines. This is due to the formation of SLS micelles. The surface excess concentration data have been used to estimate the extent of molecular packing at the gas/liquid interface and to assess interactions among surfactant molecules in order to explain trends in surface viscosity of a mixed surfactant system adsorbed from an aqueous solution. 30 references.

Djabbarah, N.F.; Wasan, D.T.

1982-02-01

46

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

UK PubMed Central (United Kingdom)

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

Yaghi N; Hartikainen H

2013-07-01

47

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

Directory of Open Access Journals (Sweden)

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

Marek DZIENIEWICZ; Henryk SECHMAN; Maciej J. KOTARBA

2009-01-01

48

Adsorbent compositions for the removal of hydrogen sulfide from fluid streams  

International Nuclear Information System (INIS)

This patent describes a sorbent composition effective in the removal of hydrogen sulfide from gaseous streams comprising zinc oxide and a Group IIA metal silicate wherein the concentration of the zinc oxide is in the range of from about 10 weight percent to about 95 weight percent based on the total combined weight of the zinc oxide and the Group IIA metal silicate.

1991-03-08

49

The adsorptive removal of disinfection by-product precursors in a high-SUVA water using iron oxide-coated pumice and volcanic slag particles.  

UK PubMed Central (United Kingdom)

The main objective of this work was to study the effectiveness of iron oxide-coated pumice and volcanic slag particles in removing disinfection by-product (DBP) precursors from a raw drinking water source with high specific UV absorbance (SUVA(254)) value. Iron oxide coating of particles significantly increased dissolved organic carbon (DOC) uptakes and decreased DBP formation after chlorination compared to uncoated particles. pH values close to neutral levels during adsorption and chlorination provided DOC, trihalomethane and haloacetic acid reductions around 60-75% employing 6 g/L coated particle dosage. Higher degree of DOC and DBP reductions (>85%) were obtained with increasing particle dose. The uptake of bromide by iron oxide surfaces was negligible and increasing bromide concentrations (up to 550 ?g/L) did not negatively impact the DOC uptake. However, due to competition between natural organic matter (NOM) and bicarbonate for the iron oxide surfaces, increasing bicarbonate alkalinity levels reduced DOC uptakes. Overall, the results indicated that the iron oxide-coated pumice/slag particles are effective adsorbents to remove NOM and control DBP formation in waters with relatively high DOC and SUVA(254) levels. However, they may not be effective for waters with alkalinity levels above 250 mg CaCO(3)/L.

Kaplan Bekaroglu SS; Yigit NO; Karanfil T; Kitis M

2010-11-01

50

Nanoparticles adsorbed at the water/oil interface: coverage and composition effects on structure and diffusion.  

Science.gov (United States)

Dissipative particle dynamics simulations are performed to study the structural and dynamical properties of various systems of nanoparticles accumulated at the water/oil interface. Homogeneous and Janus nanoparticles with different surface compositions are studied. For all nanoparticles, as the surface density increases, a transition from a liquidlike to a solidlike state is observed, as expected. At a high density of nanoparticles, hexagonal structures emerge and the nanoparticles' self-diffusion coefficient decreases because of caging effects. Similar results are observed for nanoparticles with different surface chemistry. Because different nanoparticles have different contact angles at the water/oil interface, the results obtained for systems containing mixed nanoparticles are more interesting. For example, our results show that the self-diffusion coefficient is not a monotonic function of the system composition, caused by the complex relation between hydrodynamic interactions and effective nanoparticle-nanoparticle interactions. PMID:23472643

Luu, Xuan-Cuong; Yu, Jing; Striolo, Alberto

2013-03-21

51

Nanoparticles adsorbed at the water/oil interface: coverage and composition effects on structure and diffusion.  

UK PubMed Central (United Kingdom)

Dissipative particle dynamics simulations are performed to study the structural and dynamical properties of various systems of nanoparticles accumulated at the water/oil interface. Homogeneous and Janus nanoparticles with different surface compositions are studied. For all nanoparticles, as the surface density increases, a transition from a liquidlike to a solidlike state is observed, as expected. At a high density of nanoparticles, hexagonal structures emerge and the nanoparticles' self-diffusion coefficient decreases because of caging effects. Similar results are observed for nanoparticles with different surface chemistry. Because different nanoparticles have different contact angles at the water/oil interface, the results obtained for systems containing mixed nanoparticles are more interesting. For example, our results show that the self-diffusion coefficient is not a monotonic function of the system composition, caused by the complex relation between hydrodynamic interactions and effective nanoparticle-nanoparticle interactions.

Luu XC; Yu J; Striolo A

2013-06-01

52

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

Science.gov (United States)

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

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

2007-03-29

53

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

UK PubMed Central (United Kingdom)

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

Zhang G; Qu J; Liu H; Cooper AT; Wu R

2007-06-01

54

Removal of copper on composite sewage sludge/industrial sludge-based adsorbents: the role of surface chemistry.  

UK PubMed Central (United Kingdom)

Sewage sludge and industrial waste oil sludge were pyrolyzed in an inert atmosphere at 650 or 950 degrees C, either as single components or as 50:50 mixtures. Composite materials were used as adsorbents of copper ions from aqueous solution. The capacity for copper removal was comparable to that of commercial activated carbon. To relate the performance of materials to their properties, the surface features were characterized using adsorption of nitrogen, thermal analysis, XRF, potentiometric titration, and elemental analysis. The results indicated that a high copper removal capacity could be linked to basic surface pH and specific compounds present on the surface. The high removal ability of materials obtained at 650 degrees C is attributed to cation exchange reactions between calcium and magnesium in aluminosilicates, formed on their surface during heat treatment, and copper. On the other hand, the high degree of mineralization of the surface of the materials obtained at 950 degrees C promotes copper complexation and its surface precipitation as hydroxides or hydroxylcarbonate entities.

Seredych M; Bandosz TJ

2006-10-01

55

Removal of copper on composite sewage sludge/industrial sludge-based adsorbents: the role of surface chemistry.  

Science.gov (United States)

Sewage sludge and industrial waste oil sludge were pyrolyzed in an inert atmosphere at 650 or 950 degrees C, either as single components or as 50:50 mixtures. Composite materials were used as adsorbents of copper ions from aqueous solution. The capacity for copper removal was comparable to that of commercial activated carbon. To relate the performance of materials to their properties, the surface features were characterized using adsorption of nitrogen, thermal analysis, XRF, potentiometric titration, and elemental analysis. The results indicated that a high copper removal capacity could be linked to basic surface pH and specific compounds present on the surface. The high removal ability of materials obtained at 650 degrees C is attributed to cation exchange reactions between calcium and magnesium in aluminosilicates, formed on their surface during heat treatment, and copper. On the other hand, the high degree of mineralization of the surface of the materials obtained at 950 degrees C promotes copper complexation and its surface precipitation as hydroxides or hydroxylcarbonate entities. PMID:16901497

Seredych, Mykola; Bandosz, Teresa J

2006-08-09

56

Transformation of bisphenol A by manganese oxide-coated sand.  

UK PubMed Central (United Kingdom)

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

Lin K; Peng Y; Huang X; Ding J

2013-03-01

57

Surface behaviour in deuterium permeation through erbium oxide coatings  

Science.gov (United States)

Suppression of tritium permeation through structural materials is essential in order to mitigate fuel loss and radioactivity concerns. Ceramic coatings have been investigated for over three decades as tritium permeation barriers (TPBs); however, a very limited number of investigations on the mechanism of hydrogen-isotope permeation through the coatings have been reported. In this study, deuterium permeation behaviour of erbium oxide coatings fabricated by filtered arc deposition on reduced activation ferritic/martensitic steels has been investigated. The samples coated on both sides of the substrates showed remarkably lower permeability than those coated on one side, and the maximum reduction efficiency indicated a factor of 105 compared with the substrate. The different permeation behaviour between the coatings facing the high and low deuterium pressure sides has been found by the crystal structure analysis and the evaluation of the energy barriers. It is suggested that the permeation processes on the front and back surfaces are independent, and the TPB efficiency of the samples coated on both sides can be expressed by a multiplication of that of each side.

Chikada, T.; Suzuki, A.; Adelhelm, C.; Terai, T.; Muroga, T.

2011-06-01

58

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

International Nuclear Information System (INIS)

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

2003-01-01

59

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

Digital Repository Infrastructure Vision for European Research (DRIVER)

The electrochemical behavior at room temperature in a neutral sodium chloride aqueous solution of four types of metallorganic chemical vapor deposited aluminum oxide coatings on commercial Ti6242 titanium alloy was investigated. Polarization and electrochemical impedance curves revealed that porosit...

Boisier, Grégory; Raciulete, Monica; Samélor, Diane; Pébère, Nadine; Gleizes, Alain; Vahlas, Constantin

60

Kinetics and Properties of Micro Arc Oxidation Coatings Deposited on Commercial Al Alloys  

Science.gov (United States)

The micro arc oxidation (MAO) technique is being increasingly recognized as a novel and ecofriendly means of depositing dense ceramic oxide coatings on Al and its alloys. In the present study, the deposition kinetics, surface roughness, morphology, phase distribution and the microhardness of the MAO coatings deposited on ten different commercially available Al substrates having widely differing chemical composition has been investigated. Further, the tribological properties of the coatings obtained on different Al alloys in comparison with the bare substrates have also been evaluated using dry sand abrasion, solid-particle erosion and pin-on-disc dry sliding wear tests. The results clearly demonstrate that the alloying elements added to the Al substrate substantially influence the MAO coating deposition kinetics and coating properties. In the case of Al-Si alloys, the coating deposition kinetics is non-linear and the Al6Si2O13 (mullite) is observed to form. With increasing Si content, the corresponding mullite phase also increases. Increasing mullite content in the coating adversely affects the tribological performance. Excepting Al-Si alloys, all other alloys investigated including commercial purity Al exhibit linear coating deposition kinetics. Of all the alloys investigated, Al-Li alloy exhibits the highest coating deposition rate and the 6061 T6 Al alloy exhibits the best coating properties.

Krishna, L. Rama; Purnima, A. Sudha; Wasekar, Nitin P.; Sundararajan, G.

2007-02-01

 
 
 
 
61

Activity of Trypsin Adsorbed on Temperature and pH-Responsive Micron-Sized PS/P(NIPAM-MAA-MBAAm) Composite Polymer Particles  

Science.gov (United States)

Micron-sized polystyrene (PS) seed particles were prepared by dispersion polymerization of styrene in ethanol-water media. Seeded copolymerization of N-isopropyl acrylamide (NIPAM), methacrylic acid (MAA) and N,N`-methylene-bis-acrylamide (MBAAm) was then carried out in presence of PS seed particles. The produced PS/P(NIPAM-MAA-MBAAm) composite polymer particles exhibited volume phase transition to small changes in temperature and pH, respectively. Specific activities of trypsin aqueous solution (free trypsin) and trypsin in presence of PS seed and composite polymer particles were measured under identical conditions. Relative study suggested that trypsin adsorbed on PS/P(NIPAM-MAA-MBAAm) composite polymer particles retained their native conformation.

Ashraful Alam, M.; Jalil Miah, M. A.; Ahmad, Hasan

62

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

Energy Technology Data Exchange (ETDEWEB)

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

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

2000-01-01

63

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

International Nuclear Information System (INIS)

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

2010-02-15

64

Quantifying the influence of humic acid adsorption on colloidal microsphere deposition onto iron-oxide-coated sand  

Energy Technology Data Exchange (ETDEWEB)

This article describes an approach for quantifying microsphere deposition onto iron-oxide-coated sand under the influence of adsorbed Suwannee River Humic Acid (SRHA). The experimental technique involved a triple pulse injection of model latex microspheres (microspheres) in pulses of (1) microspheres, followed by (2) SRHA, and then (3) microspheres, into a column filled with iron-coated quartz sand as a water-saturated porous medium. A random sequential adsorption model (RSA) simulated the gradual rise in the first (microsphere) breakthrough curve (BTC). Using the same model calibration parameters a dramatic increase in concentration at the start of the second particle BTC, generated after SRHA injection, could be simulated by matching microsphere concentrations to extrapolated RSA output. RSA results and microsphere/SRHA recoveries showed that 1 {mu}g of SRHA could block 5.90 {+-} 0.14 x 10{sup 9} microsphere deposition sites. This figure was consistent between experiments injecting different SRHA masses, despite contrasting microsphere deposition/release regimes generating the second microsphere BTC. - This paper describes a method to quantify the influence of humic acid adsorption on particulate colloid deposition in saturated porous media.

Yang, X. [School of Planning, Architecture and Civil Engineering, Queen' s University Belfast, David Keir Building, Stranmillis Road, Belfast, BT9 5AG Northern Ireland (United Kingdom); Flynn, R., E-mail: r.flynn@qub.ac.u [School of Planning, Architecture and Civil Engineering, Queen' s University Belfast, David Keir Building, Stranmillis Road, Belfast, BT9 5AG Northern Ireland (United Kingdom); Kammer, F. von der; Hofmann, T. [Department of Environmental Geosciences, University of Vienna, Althanstrasse 14, 1090 Vienna (Austria)

2010-12-15

65

Quantifying the influence of humic acid adsorption on colloidal microsphere deposition onto iron-oxide-coated sand  

International Nuclear Information System (INIS)

This article describes an approach for quantifying microsphere deposition onto iron-oxide-coated sand under the influence of adsorbed Suwannee River Humic Acid (SRHA). The experimental technique involved a triple pulse injection of model latex microspheres (microspheres) in pulses of (1) microspheres, followed by (2) SRHA, and then (3) microspheres, into a column filled with iron-coated quartz sand as a water-saturated porous medium. A random sequential adsorption model (RSA) simulated the gradual rise in the first (microsphere) breakthrough curve (BTC). Using the same model calibration parameters a dramatic increase in concentration at the start of the second particle BTC, generated after SRHA injection, could be simulated by matching microsphere concentrations to extrapolated RSA output. RSA results and microsphere/SRHA recoveries showed that 1 ?g of SRHA could block 5.90 ± 0.14 x 109 microsphere deposition sites. This figure was consistent between experiments injecting different SRHA masses, despite contrasting microsphere deposition/release regimes generating the second microsphere BTC. - This paper describes a method to quantify the influence of humic acid adsorption on particulate colloid deposition in saturated porous media.

2010-01-01

66

Thermodynamic and kinetic controls on cotransport of Pantoea agglomerans cells and Zn through clean and iron oxide coated sand columns.  

Science.gov (United States)

Recent observations that subsurface bacteria quickly adsorb metal contaminants raise concerns that they may enhance metal transport, given the high mobility of bacteria themselves. However, metal adsorption to bacteria is also reversible, suggesting that mobility within porous medium will depend on the interplay between adsorption-desorption kinetics and thermodynamic driving forces for adsorption. Till now there has been no systematic investigation of these important interactions. This study investigates the thermodynamic and kinetic controls of cotransport of Pantoea agglomerans cells and Zn in quartz and iron-oxide coated sand (IOCS) packed columns. Batch kinetic studies show that significant Zn sorption on IOCS takes place within two hours. Adsorption onto P. agglomerans surfaces reaches equilibrium within 30 min. Experiments in flow through quartz sand systems demonstrate that bacteria have negligible effect on zinc mobility, regardless of ionic strength and pH conditions. Zinc transport exhibits significant retardation in IOCS columns at high pH in the absence of cells. Yet, when mobile bacteria (non attached) are passed through simultaneously with zinc, no facilitated transport is observed. Adsorption onto cells becomes significant and plays a role in mobile metal speciation only once the IOCS is saturated with zinc. This suggests that IOCS exhibits stronger affinity for Zn than cell surfaces. However, when bacteria and Zn are preassociated on entering the column, zinc transport is initially facilitated. Subsequently, zinc partly desorbs from the cells and redistributes onto the IOCS as a result of the higher thermodynamic affinity for IOCS. PMID:23153272

Kapetas, Leon; Ngwenya, Bryne T; Macdonald, Alan M; Elphick, Stephen C

2012-12-03

67

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

Directory of Open Access Journals (Sweden)

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

Neeta L. Lala; Velmurugan Thavasi; Seeram Ramakrishna

2009-01-01

68

Electrophoretic deposition of diffusion barrier titanium oxide coatings for nuclear reactor cladding applications  

Science.gov (United States)

Titanium oxide coating was deposited using electrophoretic deposition method.Deposition and sintering parameters were optimized to achieve the best coating quality.Fuel-cladding chemical interaction is reduced by TiO2 diffusion barrier coatings.Co-axial EPD was used to coat inside cladding tubular geometry.

Firouzdor, Vahid; Brechtl, Jamieson; Hauch, Benjamin; Sridharan, Kumar; Allen, Todd R.

2013-10-01

69

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

Science.gov (United States)

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

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

1993-10-01

70

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

UK PubMed Central (United Kingdom)

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

Edlou SM; Smajkiewicz A; Al-Jumaily GA

1993-10-01

71

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

Science.gov (United States)

Conversion of a granular molybdenum-doped, hexagonal tungsten bronze (MoW HTB) polyacrylonitrile (PAN) composite adsorbent to a leach resistant ceramic waste form capable of immobilizing adsorbed Cs+ and Sr2+ has been achieved by heating in air at temperatures in the range 600 1200 °C. Thermal treatment of the Cs- and Sr-loaded composite material at 1000 °C was sufficient to invoke a 60% reduction in volume of the composite while still retaining its spherical morphology. Cs-133 MAS NMR studies of this sample suite at 9.4 T and 14.1 T showed that multiple Cs sites are present throughout the entire thermal treatment range. Scanning electron microscopy investigations of the phase assemblages resulting from thermal treatment demonstrated that the full complement of Cs, and the majority of Sr, partitions into HTB phases (A0.16 0.3MO3; A = Cs+, Sr2+ and Na+; M = Mo, W). The potentially reducing conditions resulting from the removal of the PAN matrix or the presence of high concentrations of Na+ relative to either Cs+ or Sr2+ does not retard the formation of the high temperature HTB phases. The fraction of Cs+ and Sr2+ leached from the tungstate phase assemblages was superior or comparable with cesium hollandite (Cs0.8Ba0.4Ti8O18; f = ?8 × 10-5; rate = <1.2 × 10-4 g/m2/day) and strontium titanate (SrTiO3; f = 3.1 × 10-3; rate = 2.63 × 10-4 g/m2/day), respectively, using a modified PCT test in Millipore water at 90 °C. Furthermore, where aggressive leaching conditions were employed (0.1 M HNO3; 150 °C; 4 days), the tungstate phase assemblages displayed leach resistance almost two orders of magnitude greater than the reference phases.

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

2006-11-01

72

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

International Nuclear Information System (INIS)

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

2006-11-30

73

Adsorber fires  

International Nuclear Information System (INIS)

[en] During normal plant operation the activated carbon filter Systems exhaust air from controlled areas of the nuclear power plant. The system to be dealt with is equipped with two 100% filter trains (= 2 x 17.500 m3/h). The total carbon volume in the adsorbers amounts to V = 10 m3, and the total carbon weight G = 5.000 kg. The activated carbon (8 - 12 mesh) satisfies ANSI/ASME N 509, being impregnated on the base of 1.5% calcium iodide. The air flow passing the adsorber is directed from the bottom to the top of the carbon bed. In each case (plant operation or shut down) the heat transport will be improved by venting the margins between the carbon particles if the amount of carbon fines is reduced to a minimum. Sufficient protection of carbon filters will be accomplished by closing the exhaust damper of the building area at risk thus preventing heat intake or accumulation of contaminants such as HCL or SO2 originating from fire hazards outside of the system. Also avoiding the clogging of the intake surface of the filters by particles of soot. The capability of the adsorption of methyl iodide by the activated carbon shall be protected

1987-01-01

74

Preparation and characterization of niobium oxide coated cellulose fiber  

International Nuclear Information System (INIS)

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

1996-01-01

75

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

International Nuclear Information System (INIS)

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

1986-01-01

76

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

International Nuclear Information System (INIS)

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

1982-01-01

77

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

Energy Technology Data Exchange (ETDEWEB)

Conversion of a granular molybdenum-doped, hexagonal tungsten bronze (MoW-HTB)-polyacrylonitrile (PAN) composite adsorbent to a leach resistant ceramic waste form capable of immobilizing adsorbed Cs{sup +} and Sr{sup 2+} has been achieved by heating in air at temperatures in the range 600-1200 deg. C. Thermal treatment of the Cs- and Sr-loaded composite material at 1000 deg. C was sufficient to invoke a 60% reduction in volume of the composite while still retaining its spherical morphology. Cs-133 MAS NMR studies of this sample suite at 9.4 T and 14.1 T showed that multiple Cs sites are present throughout the entire thermal treatment range. Scanning electron microscopy investigations of the phase assemblages resulting from thermal treatment demonstrated that the full complement of Cs, and the majority of Sr, partitions into HTB phases (A{sub 0.16-0.3}MO{sub 3}; A = Cs{sup +}, Sr{sup 2+} and Na{sup +}; M = Mo, W). The potentially reducing conditions resulting from the removal of the PAN matrix or the presence of high concentrations of Na{sup +} relative to either Cs{sup +} or Sr{sup 2+} does not retard the formation of the high temperature HTB phases. The fraction of Cs{sup +} and Sr{sup 2+} leached from the tungstate phase assemblages was superior or comparable with cesium hollandite (Cs{sub 0.8}Ba{sub 0.4}Ti{sub 8}O{sub 18}; f = {approx}8 x 10{sup -5}; rate = <1.2 x 10{sup -4} g/m{sup 2}/day) and strontium titanate (SrTiO{sub 3}; f = 3.1 x 10{sup -3}; rate = 2.63 x 10{sup -4} g/m{sup 2}/day), respectively, using a modified PCT test in Millipore water at 90 deg. C. Furthermore, where aggressive leaching conditions were employed (0.1 M HNO{sub 3}; 150 deg. C; 4 days), the tungstate phase assemblages displayed leach resistance almost two orders of magnitude greater than the reference phases.

Griffith, Christopher S. [Australian Nuclear Science and Technology Organisation, Institute of Materials and Engineering Sciences, PMB 1, Menai, NSW 2234 (Australia); Sebesta, Ferdinand [Czech Technical University in Prague, Department of Nuclear Chemistry, Brehova 7, 115 19 Prague 1 (Czech Republic); Hanna, John V. [Australian Nuclear Science and Technology Organisation, Institute of Materials and Engineering Sciences, PMB 1, Menai, NSW 2234 (Australia); Yee, Patrick [Australian Nuclear Science and Technology Organisation, Institute of Materials and Engineering Sciences, PMB 1, Menai, NSW 2234 (Australia); Drabarek, Elizabeth [Australian Nuclear Science and Technology Organisation, Institute of Materials and Engineering Sciences, PMB 1, Menai, NSW 2234 (Australia); Smith, Mark E. [Department of Physics, University of Warwick, Gibbett Hill Road, Coventry CV47AL (United Kingdom); Luca, Vittorio [Australian Nuclear Science and Technology Organisation, Institute of Materials and Engineering Sciences, PMB 1, Menai, NSW 2234 (Australia)]. E-mail: vlu@ansto.gov.au

2006-11-30

78

The interfacial chemistry of metallized, oxide coated, and nanocomposite coated polymer films  

Energy Technology Data Exchange (ETDEWEB)

Aluminium, aluminium oxide, and aluminium/aluminium oxide nanocomposite coated polymer substrates have been characterized by X-ray photoelectron spectroscopy, transmission electron microscopy, argon ion sputter depth profiling, and gas permeation measurements. A comparison of the similarities and differences between these coatings has provided a detailed insight into the physicochemical origins of gas barrier associated with metallized plastics. Keywords: Aluminium; Aluminium oxide; Coatings; X-ray photoelectron spectroscopy ((orig.))

Barker, C.P. [Durham Univ. (United Kingdom). Dept. of Chemistry; Kochem, K.H. [HOECHST Aktiengesellschaft, Werk Kalle/Albert, Geschaftsbereich H, Rheingaustrasse 190-196, D-65174 Wiesbaden (Germany); Revell, K.M. [CAMVAC (Europe) Ltd., Burrell Way, Thetford, Norfolk IP24 3QY (United Kingdom); Kelly, R.S.A. [CAMVAC (Europe) Ltd., Burrell Way, Thetford, Norfolk IP24 3QY (United Kingdom); Badyal, J.P.S. [Durham Univ. (United Kingdom). Dept. of Chemistry

1995-02-15

79

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

UK PubMed Central (United Kingdom)

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

Cui WF; Jin L; Zhou L

2013-10-01

80

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

Directory of Open Access Journals (Sweden)

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

Stela Maria de Carvalho Fernandes; Lalgudi Venkataraman Ramanathan

2004-01-01

 
 
 
 
81

Origin of complex impact craters on native oxide coated silicon surfaces  

International Nuclear Information System (INIS)

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

2008-02-15

82

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

Scientific Electronic Library Online (English)

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

Fernandes, Stela Maria de Carvalho; Ramanathan, Lalgudi Venkataraman

2004-03-01

83

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

Directory of Open Access Journals (Sweden)

Full Text Available The purpose of this study was to use scanning electron microscopy (SEM) evaluation to determine the optimal anodizetion conditions needed to generate niobium oxide coatings on titanium alloy dental implant screws. Sand-blasted titanium alloy dental implants were anodized in dilute hydrofluoric acid (HF(aq)) solution using a Sorensen DLM 300-2 power supply. The HF concentration and anodization time were varied and the resulting implant surfaces were evaluated using a Jeol JSM-5310LV Scanning Electron Microscope to determine the ideal anodization conditions. While HF is necessary to facilitate oxide growth, increasing concentrations resulted in proportionate increases in coating delamination. In a similar manner, a minimum anodization time of 1 hour was necessary for oxide growth but longer times produced more delamination especially at higher HF(aq) concentrations. SEM imaging showed that implants anodized for 1 hour in a 0.1% HF(aq) aqueous solution had the best results. Anodization can be used to generate niobium oxide coatings on sand-blasted Ti alloy dental implants by balancing the competing factors of oxide growth and coating delamination. It is believed that these oxide coatings have the potential to improve osseointegration relative to untreated dental implants when evaluated in an in vivo study.

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

2012-01-01

84

Characteristics of element composition of aerosols adsorbed on leaves by radioactivation analysis and their effects on plants  

Energy Technology Data Exchange (ETDEWEB)

Aerosol deposits on leaves of various trees, especially cedar in different regions of Japan were collected to characterize the elemental composition using neutron activation analysis, ICP-AES, etc. and also investigate the effects of deposit aerosols on plants and the efficacy as an indicator for air pollution. Compared with the elemental composition of the soil, Se, Cr, Au, Br, As, Sb, Ag, etc. were more abundant in aerosols on cedar leaves. Especially, Sb is thought to be mostly derived from combustion of fossil fuels (exhaust gas from cars, etc.). Since Sb was accumulated on leaves at high levels and the analytical precision for Sb by neutron radioactivation was very high, the element was thought useful as an indicator for air pollution. If the amounts of Sb on the leaves of cedar and pine trees, which are widely distributed in Japan are determined, the degrees of pollution in all regions of Japan would be determined. In cedar trees of Saitama Prefecture where the deposit amounts of aerosols were comparatively larger, 42% of stoma was covered with the deposits, resulting that the rate of cuticular transpiration was increased and the amounts of basic elements leached from the leave surface was also increased. Thus, it was suggested that these changes might be the cause of recent declining of cedars in Japanese urban regions. (M.N.)

Takamatsu, Takejiro; Koshikawa, Masami [National Inst. for Environmental Studies, Tsukuba, Ibaraki (Japan); Sase, Hiroyuki; Masuzawa, Toshiyuki; Kawashima, Munetsugu; Takada, Jitsuya; Matsushita, Rokuji

1999-01-01

85

Characteristics of element composition of aerosols adsorbed on leaves by radioactivation analysis and their effects on plants  

International Nuclear Information System (INIS)

[en] Aerosol deposits on leaves of various trees, especially cedar in different regions of Japan were collected to characterize the elemental composition using neutron activation analysis, ICP-AES, etc. and also investigate the effects of deposit aerosols on plants and the efficacy as an indicator for air pollution. Compared with the elemental composition of the soil, Se, Cr, Au, Br, As, Sb, Ag, etc. were more abundant in aerosols on cedar leaves. Especially, Sb is thought to be mostly derived from combustion of fossil fuels (exhaust gas from cars, etc.). Since Sb was accumulated on leaves at high levels and the analytical precision for Sb by neutron radioactivation was very high, the element was thought useful as an indicator for air pollution. If the amounts of Sb on the leaves of cedar and pine trees, which are widely distributed in Japan are determined, the degrees of pollution in all regions of Japan would be determined. In cedar trees of Saitama Prefecture where the deposit amounts of aerosols were comparatively larger, 42% of stoma was covered with the deposits, resulting that the rate of cuticular transpiration was increased and the amounts of basic elements leached from the leave surface was also increased. Thus, it was suggested that these changes might be the cause of recent declining of cedars in Japanese urban regions. (M.N.)

1999-01-01

86

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

Science.gov (United States)

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

Dai, Mingzhi; Vogt, Bryan D

2012-07-06

87

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

UK PubMed Central (United Kingdom)

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

Dai M; Vogt BD

2012-12-01

88

Characterization of microarc oxidation coatings formed on AM60B magnesium alloy in silicate and phosphate electrolytes  

International Nuclear Information System (INIS)

Microarc oxidation coatings on AM60B magnesium alloy were prepared in silicate and phosphate electrolytes. Structure, composition, mechanical property, tribological, and corrosion resistant characteristics of the coatings was studied by scanning electron microscope (SEM), X-ray diffraction (XRD) and microhardness analyses, and by ball-on-disc friction and potentiodynamic corrosion testing. It is found that the coating produced from the silicate electrolyte is compact and uniform and is mainly composed of MgO and forsterite Mg2SiO4 phases, while the one formed in phosphate electrolyte is relatively porous and is mainly composed of MgO phase. The thick coating produced from a silicate electrolyte possesses a high hardness and provides a low wear rate (3.55 x 10-5 mm3/Nm) but a high friction coefficient against Si3N4 ball. A relatively low hardness and friction coefficient while a high wear rate (8.65 x 10-5 mm3/Nm) is recorded during the testing of the thick coating produced from a phosphate electrolyte. Both of these types of coatings provide effective protection for the corrosion resistance compared with the uncoated magnesium alloy. The coating prepared from the silicate electrolyte demonstrates better corrosion behavior due to the compacter microstructure.

2007-03-15

89

Peroxide induced tin oxide coating of graphene oxide at room temperature and its application for lithium ion batteries  

International Nuclear Information System (INIS)

[en] We describe a new, simple and low-temperature method for ultra-thin coating of graphene oxide (GO) by peroxostannate, tin oxide or a mixture of tin and tin oxide crystallites by different treatments. The technique is environmentally friendly and does not require complicated infrastructure, an autoclave or a microwave. The supported peroxostannate phase is partially converted after drying to crystalline tin oxide with average, 2.5 nm cassiterite crystals. Mild heat treatment yielded full coverage of the reduced graphene oxide by crystalline tin oxide. Extensive heat treatment in vacuum at >500? °C yielded a mixture of elemental tin and cassiterite tin oxide nanoparticles supported on reduced graphene oxide (rGO). The usefulness of the new approach was demonstrated by the preparation of two types of lithium ion anodes: tin oxide–rGO and a mixture of tin oxide and tin coated rGO composites (SnO2–Sn–rGO). The electrodes exhibited stable charge/discharge cyclability and high charging capacity due to the intimate contact between the conductive graphene and the very small tin oxide crystallites. The charging/discharging capacity of the anodes exceeded the theoretical capacity predicted based on tin lithiation. The tin oxide coated rGO exhibited higher charging capacity but somewhat lower stability upon extended charge/discharge cycling compared to SnO2–Sn–rGO. (paper)

2012-12-07

90

Granular iron oxide adsorbents to control natural organic matter and membrane fouling in ultrafiltration water treatment.  

Science.gov (United States)

Fine iron oxide particles (IOPs) are effective in removing natural organic matter (NOM) that causes membrane fouling in water treatment, but the separation of used IOPs is problematic. This study focused on the fabrication and use of granular iron oxide adsorbents, in combination with ultrafiltration (UF) membranes while investigating the NOM removal efficiency and fouling control. Sulfonated styrene-divinylbenzene copolymer beads were coated with two types of iron oxides (ferrihydrite and magnetite) and their performances were compared to that of fine IOPs. A significant amount of iron oxide coating (52-63 mg of Fe per g bead) was achieved by means of electrostatic binding and hydrolysis of iron ions. Iron oxide coated polymer (IOCP) beads were able to remove some amounts (?20%) of dissolved organic carbon (DOC) comparable to that achieved by IOPs within a short period of time (1000 kDa which is believed to be responsible for severe UF fouling. PMID:23764573

Cui, Xiaojun; Choo, Kwang-Ho

2013-05-11

91

Tunable Adsorbate-Adsorbate Interactions on Graphene  

Science.gov (United States)

We propose a mechanism to control the interaction between adsorbates on graphene. The interaction between a pair of adsorbates—the change in adsorption energy of one adsorbate in the presence of another—is dominated by the interaction mediated by graphene’s ? electrons and has two distinct regimes. Ab initio density functional, numerical tight-binding, and analytical calculations are used to develop the theory. We demonstrate that the interaction can be tuned in a wide range by adjusting the adsorbate-graphene bonding or the chemical potential.

Solenov, Dmitry; Junkermeier, Chad; Reinecke, Thomas L.; Velizhanin, Kirill A.

2013-09-01

92

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

Directory of Open Access Journals (Sweden)

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

Q. Fu; J. C. Wang; P. Chen; L. Chen; K. Wang; H. Deng; F. Chen; Q. Zhang

2012-01-01

93

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

Directory of Open Access Journals (Sweden)

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

VLADIMIR V. PANIC; BRANISLAV Z. NIKOLIC

2007-01-01

94

Evaluating the electrochemical capacitance of surface-charged nanoparticle oxide coatings.  

UK PubMed Central (United Kingdom)

While transition metal oxides have been thoroughly investigated as coatings for electrochemical capacitors due to their pseudocapacitance, little work has been done investigating other oxide coatings. There exists a whole class of nanoporous oxides typically synthesized by sol-gel chemistry techniques that have very high differential capacitance. This high differential capacitance has been attributed to the surface potential of these materials and the close approach of counterions near the surface of these oxides. This study focuses on investigating the electrochemical capacitance of non-transition metal oxide nanoparticle coatings when deposited on supporting electrodes. Here, we show that, by adding coatings of SiO(2), AlOOH, TiO(2), and ZrO(2) nanoparticles to graphite support electrodes, we can increase the electrochemical capacitance. We also show that the measured electrochemical capacitance of these oxide-coated electrodes directly relates to the electrophoretic mobility of these materials with the lowest values in capacitance occurring at or near the respective isoelectric pH (pH(IEP)) of each oxide.

Leonard KC; Suyama WE; Anderson MA

2012-04-01

95

Influence of ionic strength and pH on the limitation of latex microsphere deposition sites on iron-oxide coated sand by humic acid  

International Nuclear Information System (INIS)

This study, for the first time, investigates and quantifies the influence of slight changes in solution pH and ionic strength (IS) on colloidal microsphere deposition site coverage by Suwannee River Humic Acid (SRHA) in a column matrix packed with saturated iron-oxide coated sand. Triple pulse experimental (TPE) results show adsorbed SRHA enhances microsphere mobility more at higher pH and lower IS and covers more sites than at higher IS and lower pH. Random sequential adsorption (RSA) modelling of experimental data suggests 1 ?g of adsorbed SRHA occupied 9.28 ± 0.03 x 109 sites at pH7.6 and IS of 1.6 mMol but covered 2.75 ± 0.2 x 109 sites at pH6.3 and IS of 20 mMol. Experimental responses are suspected to arise from molecular conformation changes whereby SRHA extends more at higher pH and lower ionic strength but is more compact at lower pH and higher IS. Results suggest effects of pH and IS on regulating SRHA conformation were additive. - Highlights: ? We quantified the coupled role of pH and IS and humic acid on colloid deposition. ? Humic acid enhances microsphere mobility more at higher pH and lower IS. ? pH and IS may control the behaviour of humic acid by regulating its conformation. ? The effect of pH and IS on regulating humic acid conformation is additive. - This paper quantifies the impact of pH and ionic strength on the transient deposition behaviour of colloids in porous medium in the presence of humic acid.

2011-01-01

96

Performance of an indium-tin-oxide-coated cobalt oxide selective absorber  

Energy Technology Data Exchange (ETDEWEB)

Efforts have been made to improve the selective performance of a cobalt oxide absorber by providing it with an optimized transparent and I.R. reflective shield of indium-tin-oxide. For optimal selectivity of the spray-pyrolysed indium-tin-oxide coating, it has been observed that, besides a dopant (tin) concentration of 8.0 mol % in the indium oxide layer, a growth temperature of 500-550/sup 0/C and a minimum layer thickness of 0.3 ..mu..m is favourable. Applying this coating on the cobalt oxide absorber gives a better spectral-selective surface for intermediate-temperature solar collectors, with a solar absorptance of 0.90 and thermal emittance of 0.12-0.13.

Choudhury, C.

1986-01-01

97

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

International Nuclear Information System (INIS)

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

2012-03-30

98

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

International Nuclear Information System (INIS)

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

2009-03-09

99

Evaluation of the mechanical properties of microarc oxidation coatings and 2024 aluminium alloy substrate  

CERN Document Server

A determination of the phase constituents of ceramic coatings produced on Al-Cu-Mg alloy by microarc discharge in alkaline solution was performed using x-ray diffraction. The profiles of the hardness, H, and elastic modulus, E, across the ceramic coating were determined by means of nanoindentation. In addition, a study of the influence of microarc oxidation coatings on the tensile properties of the aluminium alloy was also carried out. The results show that the H-and E-profiles are similar, and both of them exhibit a maximum value at the same depth of coating. The distribution of the alpha-Al sub 2 O sub 3 phase content determines the H- and E-profiles of the coatings. The tensile properties of 2024 aluminium alloy show less change after the alloy has undergone microarc discharge surface treatment.

Xue Wen Bin; Deng Zhi Wei; Chen Ru Yi; Li Yong Liang; Zhang Ton Ghe

2002-01-01

100

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

Directory of Open Access Journals (Sweden)

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

Nie Yining; Kalapos Carol; Nie Xueyuan; Murphy Monica; Hussein Riyad; Zhang Jing

2010-01-01

 
 
 
 
101

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

UK PubMed Central (United Kingdom)

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

Nie Y; Kalapos C; Nie X; Murphy M; Hussein R; Zhang J

2010-01-01

102

Adsorbent-treated cat cracked gasoline in motor fuels  

Energy Technology Data Exchange (ETDEWEB)

A methof is described for supressing carburetor deposit formation of motor fuels containing untreated cat cracked gasoline by blending adsorbent-treated cat cracked gasoline into the motor fuel. Up to about 50 percent by weight of the total composition is adsorbent treated cat cracked gasoline, but preferably from about 5 to about 25 percent by weight of the total composition is adsorbent treated cat cracked gasoline. In a preferred embodiment a standard reference fuel capable of providing a predetermined level of carburetor deposit formation is provided by the addition of either adsorbent-treated cat cracked gasoline, untreated cat cracked gasoline, or aromatic amines to a base fuel.

Thomas, S.P.

1980-09-30

103

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

Energy Technology Data Exchange (ETDEWEB)

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

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

2009-11-13

104

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

International Nuclear Information System (INIS)

Protective coatings were successfully formed on biomedical NiTi alloy by micro-arc oxidation (MAO) using pulsed bipolar power supply. The coating surface exhibits a typical MAO porous structure, and the coating mainly consists of O, Al, Ti and Ni, with the atomic concentration of 65.11%, 27.77%, 2.20% and 2.8%, respectively. The thickness of MAO coating is about 24.0 ?m when the duration time of the MAO treatment was 90 min at 400 V constant voltage treatment. XRD analysis showed that micro-arc oxidation coating is composed of ?-Al2O3 and ?-Al2O3. The wear resistance of the coatings was investigated by ball-on-disk friction test. The microhardness of the NiTi alloy is greatly enhanced due to the formation of Al2O3 coating after micro-arc oxidation treatment. The friction coefficient of the coated NiTi is stable at 0.85 and the wear resistance is increased by 9 times compared with uncoated NiTi. The wear mechanism transforms from abrasive-dominant for the uncoated sample to adhesive-dominant for the coated sample.

1500-01-00

105

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

International Nuclear Information System (INIS)

Tungsten trioxide (WO3) electrochromic coatings have been formed on indium tin oxide-coated glass substrates by aqueous routes. Coating sols are obtained by dissolving tungsten powder in acetylated (APTA) or plain peroxotungstic acid (PTA) solutions. The structural evolution and electrochromic performance of the coatings as a function of calcination temperature (250 oC and 400 oC) have been reported. Differential scanning calorimetry and X-ray diffraction have shown that amorphous WO3 films are formed after calcination at 250 oC for both processing routes; however, the coatings that calcined at 400 oC were crystalline in both cases. The calcination temperature-dependent crystallinity of the coatings results in differences in optical properties of the coatings. Higher coloration efficiencies can be achieved with amorphous coatings than could be seen in the crystalline coatings. The transmittance values (at 800 nm) in the colored state are 35% and 56% for 250 oC and 400 oC-calcined coatings, respectively. The electrochemical properties are more significantly influenced by the method of sol preparation. The ion storage capacities designating the electrochemical properties are found in the range of 1.62-2.74 x 10-3 (mC cm-2) for APTA coatings; and 0.35-1.62 x 10-3 (mC cm-2) for PTA coatings. As a result, a correlation between the microstructure and the electrochromic performance has been established.

2009-11-02

106

Tin-oxide-coated anodized aluminium selective absorber surfaces. Pt. 2. Aging and durability  

Energy Technology Data Exchange (ETDEWEB)

Accelerated aging tests on tin-oxide-coated anodized aluminium selective absorber surfaces have been performed. It is shown that the tin oxide layer provides excellent protection for the anodized surface. The thermal stability of the double layer is equal to, or better than, the stability of the bare anodized surface. Both surfaces degrade very slowly at 450deg C. The anodic layer is porous and therefore not very scratch resistant and it degrades when exposed to humidity, both acidic and alcaline. It is shown that the tin oxide film, which is hard and chemically very stable, almost completely protects the anodized surface from chemical degradation. The mechanical wear resistance is also considerably improved. The optical selectivity does not quite match that of the the anodized surface, but the remarkable stability together with the solar parameters of {alpha}=0.91 and hemispherical emittance {epsilon}= 0.16 (normal emittance {epsilon}{sub n}=0.12) make this surface an interesting selective absorber surface. (orig.).

Roos, A.; Georgson, M. (Uppsala Univ. (Sweden). Dept. of Technology)

1991-03-01

107

Retention of tannic acid and condensed tannin by Fe-oxide-coated quartz sand.  

Science.gov (United States)

This paper intends to shed light on the interactions between tannin and mineral soil particles. For that purpose, aqueous solution of condensed tannin (CT) (derived from Black pine (Pinus nigra var. maritima)) and commercially available tannic acid (TA) were added to purified quartz (Qtz) sand and quartz sand coated with either goethite (Gt) or ferrihydrite (Fh). After solvent removal by evaporation the samples were extracted by water. The extracts were analysed for organic carbon, total phenolics and CT. The extractability of the two tannins was small and increased in the order Qtz-Fh < Qtz-Gt < Qtz. For all mineral samples, TA was more extractable than CT. Bonding of tannins to the mineral samples and the partial peptisation of the Fe oxide coatings upon the binding resulted in complex tannin release curves. Our results suggest that the inextractability of tannins from natural soils and the absence of tannins in soil leachates might be caused by strong adsorption on soil minerals such as Qtz and Fe (oxy)(hydr)oxides. The results of competition experiments with mixtures of both tannins demonstrate that the CTs, and TA in particular, can release large amounts of Fe (oxides), suggesting that the tannins are excellent metal-mobilising agents. We therefore suggest that the fate of tannins in the mineral soil environment is highly dependent on the abundance of weakly bonded secondary oxides. PMID:15914150

Kaal, J; Nierop, K G J; Verstraten, J M

2005-07-01

108

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

Scientific Electronic Library Online (English)

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

Lanza, Marcos Roberto V.; Bertazzoli, Rodnei

2002-06-01

109

Removal of lead ions by acid activated and manganese oxide-coated bentonite.  

UK PubMed Central (United Kingdom)

This paper presents the adsorption of Pb(II) from aqua solutions onto Unye (Turkey) bentonite in raw (RB), acid activated (AAB) and manganese oxide-coated (MCB) forms. Adsorption of Pb(II) by RB, AAB and MCB sample was investigated as a function of the initial Pb(II) concentration, solution pH, ionic strength, temperature and inorganic ligand (Cl(-)). Changes in the surfaces and structure were characterized by means of XRD, IR and potentiometric titration. The Langmuir monolayer adsorption capacities of RB, AAB and MCB in 0.1M KNO(3) solution were estimated as 16.70, 8.92 and 58.88 mg/g, respectively. The spontaneity of the adsorption process is established by decrease in DeltaG which varied from -21.60 to -28.60 kJ/mol (RB), -22.63 to -29.98 kJ/mol (AAB) and -19.57 to -26.22 (MCB) in temperature range 303-338 K.

Eren E; Afsin B; Onal Y

2009-01-01

110

Evaluation of cerium oxide coated Cu cermets as inert anodes for aluminum electrowinning  

Energy Technology Data Exchange (ETDEWEB)

Cu/NiFe{sub 2}O{sub 4} cermets were evaluated, with and without an in-situ deposited CEROX (TM; cerium oxide) coating, in 100 h laboratory A1 electrowinning tests. Bath ratio and current density were varied between tests and corrosion was determined by contamination of the aluminum and cryolite by cermet components (Cu, Fe, and Ni). Higher bath ratios of 1.5 to 1.6 led to less corrosion and thicker CEROX coatings. Lower current densities led to slightly less corrosion but much less oxidation of the Cu cermet substrate. At identical test conditions, the corrosion of the CEROX coated cermets was 1/7 that of an uncoated cermet. Corrosion was increased in CEROX coated cermets tested under unsaturated alumina conditions. The electrical conductivity of the CEROX coating was measured to be {approximately}0.2 ohm{sup {minus}1}cm{sup {minus}1}, resulting in a slight voltage penalty, depending on the thickness of the coating.

1992-08-01

111

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

International Nuclear Information System (INIS)

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

2005-07-22

112

Experimental study and numerical modelling of the nickel oxide coating on the Ni(111) surface  

Energy Technology Data Exchange (ETDEWEB)

The evolution of the nickel oxide coating developed on the mono-crystalline Ni(111) surface was studied both experimentally and by means of numerical modelling. The NiO/Ni system was submitted to a high-temperature creep in the oxygen atmosphere. Using the O{sup 18} diffusion method we were able to observe several deformation modes (diffusional creep, gliding at the interfaces, etc.) and periodic crack generation perpendicular to the stress direction. The periodicity of the cracks array depends strongly on the external stress applied to the oxide scale. Two-step numerical modelling of the process was performed using first a simplified 1D model and then the 3D finite elements approach. The modelling procedure takes into account epitaxial deformations due to the scale ordering and to the mismatch of the lattice parameters, the growth process and the periodic crack generation. Identification of the visco-elastic material law permits then to obtain the strain (and the stress) distribution in the scale and in the substrate. The comparison of the experimental data with the numerical results will allow the formulation of several criteria for the oxide scale adherence. (orig.)

Vallino, N.; Gaillet, L.; Lahoche, L.; Roelandt, J.M.; Moulin, G. [Universite de Technologie de, Compiegne (France). Dept. GSM; Lorman, V.L. [LPM, CNRS - Universite Montpellier 2, Place Eugene Bataillon, 34095, Montpellier (France); Rochal, S.B. [Faculty of Physics, Rostov State University, 5 Zorge St., 344090, Rostov-on-Don (Russian Federation)

2000-12-01

113

Reduced bleaching in organic nanofibers by bilayer polymer/oxide coating  

International Nuclear Information System (INIS)

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

2010-05-15

114

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

Science.gov (United States)

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

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

2009-02-21

115

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

UK PubMed Central (United Kingdom)

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

Boonfueng T; Axe L; Yee N; Hahn D; Ndiba PK

2009-05-01

116

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

Energy Technology Data Exchange (ETDEWEB)

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

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

2009-01-01

117

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

Directory of Open Access Journals (Sweden)

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

Teti Estiasih1); Moch Adnan2); Tranggono2); Suparmo2)

2005-01-01

118

Anodic oxide coatings on metals and anodic protection /2nd revised and enlarged edition/. Anodnye oksidnye pokrytiia na metallakh i anodnaia zashchita /2nd revised and enlarged edition/  

Energy Technology Data Exchange (ETDEWEB)

The theoretical principles underlying the formation of oxide and, in particular, anodic oxide coatings on metals produced by chemical oxidation, anodizing in solutions, and anodizing in cold plasmas are reviewed. The mechanisms and conditions of anodic oxidation are described, and the structure of anodic oxide coatings on aluminum, magnesium, beryllium, zinc, cadmium, iron, cobalt, nickel, titanium, zirconium, tantalum, and chromium alloys is examined. Attention is also given to various applictins of anodized coatings. 54 references.

Frantsevich, I.N.; Piliankevich, A.N.; Lavrenko, V.A.; Volfson, A.I.

1985-01-01

119

The Study of the Oxide Coating Effect on Bone-Implant Interface Formation by Means of Electron Microscopy Method with Energy Dispersive X-ray Analysis  

International Nuclear Information System (INIS)

The experimental results of the measurement of the tissue constituent elements distribution, as well as impurity elements in the tissues around a Ti-implant with protective TiO2 oxide coating are presented. Study of morphology, qualitative and quantitative analysis were carried out by means of scanning electron microscopy method with energy dispersive X-ray analysis. The results show weak migration of Ti into the bone tissue near the interface and protective role of the oxide coatings.

2006-01-01

120

Granular iron oxide adsorbents to control natural organic matter and membrane fouling in ultrafiltration water treatment.  

UK PubMed Central (United Kingdom)

Fine iron oxide particles (IOPs) are effective in removing natural organic matter (NOM) that causes membrane fouling in water treatment, but the separation of used IOPs is problematic. This study focused on the fabrication and use of granular iron oxide adsorbents, in combination with ultrafiltration (UF) membranes while investigating the NOM removal efficiency and fouling control. Sulfonated styrene-divinylbenzene copolymer beads were coated with two types of iron oxides (ferrihydrite and magnetite) and their performances were compared to that of fine IOPs. A significant amount of iron oxide coating (52-63 mg of Fe per g bead) was achieved by means of electrostatic binding and hydrolysis of iron ions. Iron oxide coated polymer (IOCP) beads were able to remove some amounts (? 20%) of dissolved organic carbon (DOC) comparable to that achieved by IOPs within a short period of time (<15 min). Regenerated IOCPs exhibited the same sorption capacity as the fresh ones. The integrated IOCP/UF system operation with a 15-min empty bed contact time and 10-h cyclic regeneration maintained the 20% DOC removal with no sign of significant membrane fouling. In contrast, a sharp transmembrane pressure buildup occurred in the UF system when no iron oxide pretreatment was applied, regardless of the types of membranes tested. Iron oxide adsorbed the NOM fraction with molecular weights of >1000 kDa which is believed to be responsible for severe UF fouling.

Cui X; Choo KH

2013-09-01

 
 
 
 
121

Mechanical-resistance measurements of adsorbents intended for renovation of AU-1500 adsorbers of NPP airdischarge purification systems  

International Nuclear Information System (INIS)

[en] The present paper deals wits the measurements mechanical frictional resistance of variety of new carbon adsorbents produced by Ukraine, Russia and Germany. The most promising from the strength standpoint coals have been determined for their use in the adsorbers of coal filters AU-1500 studies were made into the effect of fractional composition and degree of adsorption space filling with damp on the mechanical strength of adsorbent SKT-3I.

2011-01-01

122

Fabrication and evaluation of low-cost agarose-zinc nanoporous composite matrix: influence of adsorbent density and size distribution on the performance of expanded beds.  

Science.gov (United States)

Expanded bed adsorption (EBA), a promising and practical separation technique for adsorption of nanobioproduct/bioproduct, has been widely studied in the past two decades. The development of adsorbent with the special design for expanded bed process is a challenging course. To reduce the costs of adsorbent preparation, fine zinc powder was used as the inexpensive densifier. A series of matrices named Ag-Zn were prepared by water-in-oil emulsification method. The structure and morphology of the prepared matrix were studied by the optical microscope (OM) and scanning electron microscopy (SEM). The physical properties as a function of zinc powder ratio to agarose slurry were measured. The prepared matrices had regular spherical shape, and followed logarithmic normal size distribution with the range of 75-330 ?m, mean diameter of 140.54-191.11 ?m, wet density of 1.33-2.01 g/ml, water content of 0.45-0.75, porosity of 0.86-0.97 and pore size of about 40-90 nm. The bed expansion factor at the range of 2-3 was examined. The obtained results indicated that the expansion factor was decreased with increasing of matrix density. In addition, it was found that matrices with large particle size were suitable for high operation flow rate. The hydrodynamic properties were determined in expanded bed by the residence time distribution method (RTD). The effects of flow velocity, expansion factor and density of matrix on the hydrodynamic properties were also investigated. Moreover, the influence of particle size distribution on the performance of expanded bed has been studied. Therefore, three different particle size fractions (65-140, 215-280 and 65-280 ?m) were assessed. The results indicated that dispersion in liquid-solid expanded beds increased with increasing flow rate and expansion factor; and matrix with a wide particle size distribution leaded to a reduced axial dispersion compared to matrices with a narrow size distribution. The axial dispersion coefficient also enhanced with the increasing of matrix density. It was found that flow rate was the most essential factor to effect on the hydrodynamic characteristics in the bed. For all the prepared matrices, the values of axial mixing coefficients (D(axl)) were smaller than 1.0 × 10?? m²/s when flow velocities in expanded bed were less than 700 cm/h. All the results indicate that the prepared matrix show good expansion and stability in expanded bed; and it is suitable for expanded bed processes as an economical adsorbent. PMID:22920304

Asghari, Fateme; Jahanshahi, Mohsen

2012-08-13

123

Fabrication and evaluation of low-cost agarose-zinc nanoporous composite matrix: influence of adsorbent density and size distribution on the performance of expanded beds.  

UK PubMed Central (United Kingdom)

Expanded bed adsorption (EBA), a promising and practical separation technique for adsorption of nanobioproduct/bioproduct, has been widely studied in the past two decades. The development of adsorbent with the special design for expanded bed process is a challenging course. To reduce the costs of adsorbent preparation, fine zinc powder was used as the inexpensive densifier. A series of matrices named Ag-Zn were prepared by water-in-oil emulsification method. The structure and morphology of the prepared matrix were studied by the optical microscope (OM) and scanning electron microscopy (SEM). The physical properties as a function of zinc powder ratio to agarose slurry were measured. The prepared matrices had regular spherical shape, and followed logarithmic normal size distribution with the range of 75-330 ?m, mean diameter of 140.54-191.11 ?m, wet density of 1.33-2.01 g/ml, water content of 0.45-0.75, porosity of 0.86-0.97 and pore size of about 40-90 nm. The bed expansion factor at the range of 2-3 was examined. The obtained results indicated that the expansion factor was decreased with increasing of matrix density. In addition, it was found that matrices with large particle size were suitable for high operation flow rate. The hydrodynamic properties were determined in expanded bed by the residence time distribution method (RTD). The effects of flow velocity, expansion factor and density of matrix on the hydrodynamic properties were also investigated. Moreover, the influence of particle size distribution on the performance of expanded bed has been studied. Therefore, three different particle size fractions (65-140, 215-280 and 65-280 ?m) were assessed. The results indicated that dispersion in liquid-solid expanded beds increased with increasing flow rate and expansion factor; and matrix with a wide particle size distribution leaded to a reduced axial dispersion compared to matrices with a narrow size distribution. The axial dispersion coefficient also enhanced with the increasing of matrix density. It was found that flow rate was the most essential factor to effect on the hydrodynamic characteristics in the bed. For all the prepared matrices, the values of axial mixing coefficients (D(axl)) were smaller than 1.0 × 10?? m²/s when flow velocities in expanded bed were less than 700 cm/h. All the results indicate that the prepared matrix show good expansion and stability in expanded bed; and it is suitable for expanded bed processes as an economical adsorbent.

Asghari F; Jahanshahi M

2012-09-01

124

ADSORBENT FOR PROTECTION FACILITIES  

UK PubMed Central (United Kingdom)

FIELD: sorbents. SUBSTANCE: invention relates to production of carbon-based adsorbents, in particular those adsorbing organic vapors (benzene, toluene, cyclohexane, etc. ), inorganic gases and vapors (sulfur hydride, hydrogen cyanide, chlorine, etc.), acid gases and vapors (sulfur dioxide, hydrogen chloride, hydrogen fluoride, etc.), and ammonia in protection facilities. Adsorbent based on impregnated activated carbon is a mechanical mixture composed of two constituents, the first constituent (45-55 vol %) containing copper oxides 0.5-10.0% (calculated as copper) and sodium and/or potassium carbonate 3.0-17.0% and the second one (55-45 vol %) containing copper sulfate 12.0-15.0%. Carbon base utilized is activated carbon prepared from nut shell and/or fruit stone. EFFECT: prolonged protection time. 2 tbl

GALKIN E A; ROMANOV JU A; LJANG A V; LJANG I G

125

Clustering in adsorbed films  

International Nuclear Information System (INIS)

Recently, J.G. Dash has shown that adsorption isotherms can show distincts types of behavior. In class I the bulk vapor pressure is reached asymptotically for an infinite adsorbed amount; in Class II it is reached for a finite amount; in Class III no adsorption takes place at all. These possibilities can also be derived by a simple discussion of the possible forms of the free energy as function of the thickness of the adsorbed film. The question of clustering, i.e. the formation of drops, is also discussed

1978-01-01

126

Troubleshooting carbon adsorber systems  

Energy Technology Data Exchange (ETDEWEB)

Carbon adsorption systems offer an effective way to treat volatile organic compounds (VOCs) and odor emissions. Composed of four major components, these systems include an inlet stream and desorption media, absorber bed, outlet stream, and instrumentation. Today's tough environmental compliance regulations leave little room for operating errors. An inplant carbon adsorber may seem economically insignificant, but its malfunction could result in hefty noncompliance penalties. In an adequately sized, properly specified system, most equipment problems are prevented by following routine maintenance. The paper discusses some of the maintenance procedures: adjusting for inlet stream; maintaining the adsorber bed; caring for the outlet streams; and instrumentation maintenance.

Shah, G.C. (Fina Oil and Chemical, Bayport, TX (United States))

1994-03-01

127

Bacterial removal in flow-through columns packed with iron-manganese bimetallic oxide-coated sand.  

UK PubMed Central (United Kingdom)

The objective of this study was to investigate the performance of iron-manganese bimetallic oxide-coated sand (IMCS) in the removal of bacteria (Escherichia coli ATCC 11105) using small-scale (length = 20 cm, inner diameter = 2.5 cm) and 30-day long-term (length = 50 cm, inner diameter = 2.5 cm) column experiments. Results indicated that the bacterial removal capacity of IMCS (q(eq) = 0.66 g/g) was slightly lower than that of iron oxide-coated sand (ICS) (q(eq) = 0.69 g/g) but about two times greater than those of manganese oxide-coated sand (MCS, q(eq) = 0.30 g/g) and dual media containing ICS and MCS (q(eq) = 0.35 g/g). In IMCS, increasing the flow rate from 0.5 to 3.0 mL/min decreased the removal capacity from 1.14 to 0.64 g/g. Nitrate showed an enhancement effect on the removal capacity of IMCS at 1 and 10 mM, while phosphate and bicarbonate had both hindrance (1 mM) and enhancement (10 mM) effects, depending on their concentrations. The long-term column experiment (bacterial injection conc. = 4.2 × 10(6) CFU/mL) showed that IMCS could remove more than 99.9 % of bacteria within 13 days (effluent conc. = 1.6 × 10(2) CFU/mL). This study demonstrated that IMCS could be used as an adsorptive filter medium for bacterial removal in water treatment.

Park SJ; Lee CG; Kim SB; Chang YY; Yang JK

2012-01-01

128

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

Science.gov (United States)

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

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

2011-06-06

129

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

UK PubMed Central (United Kingdom)

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

Swaminathan V; Zeng H; Lawrynowicz D; Zhang Z; Gilbert JL

2011-08-01

130

Control of photophysical and photochemistry of colloidal quantum dots via metal and metal-oxide coated substrates  

Science.gov (United States)

We studied how deposition of a very thin layer of gold or chromium oxide on glass substrates can modify the way irradiation changes the fluorescence of CdSe/ZnS quantum dots. We found that the gold layer tends to shield the quantum dots from the substrate, preventing photoinduced fluorescence enhancement caused by the Coulomb blockage. In this case the emission of the quantum dots did not show also any broadening but rather a slight red shift, independent of the irradiation time. In the case of the chromium-oxide coated substrates we observed significant broadening and blue shift, indicating such oxide could enhance photo-oxidation of colloidal quantum dots significantly.

Sadeghi, S. M.; Nejat, A.

2013-03-01

131

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

Directory of Open Access Journals (Sweden)

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

Yi Liu; Ryuichi Sugimoto; Katsuhiro Sumi

2013-01-01

132

Adsorbent and adsorbent bed for materials capture and separation processes  

Energy Technology Data Exchange (ETDEWEB)

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

Liu, Wei (Richland, WA)

2011-01-25

133

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

International Nuclear Information System (INIS)

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

2010-01-01

134

Quantifying the influence of EDTA on polymer nanoparticle deposition and retention in an iron-oxide-coated sand column.  

UK PubMed Central (United Kingdom)

Ethylenediaminotetraacetic acid (EDTA) occurring in groundwater aquifers complicates the prediction of nanoparticle movement in the porous medium. This paper demonstrates an approach combining Triple Pulse Experiments (TPEs) and numerical modelling to quantify the influence of EDTA on the deposition and retention of polymer nanoparticles in a water-saturated column packed with iron-oxide-coated sand. TPEs injecting three successive pulses in the order of nanoparticle, EDTA, nanoparticle permit nanoparticle deposition in the absence and the presence of EDTA to be compared. Random Sequential Adsorption (RSA) modelling of the nanoparticle breakthrough curves combining mass balance calculation allows the influence of EDTA to be quantified. TPE results demonstrate that the injected EDTA eluted the oxide coatings (favorable deposition sites) from the sand surface and the resulting decline in sites led to enhanced nanoparticle mobility in the subsequent pulse. Quantification results suggest that at the experimental time-scale and under the controlled conditions, elution of one deposition site requires injection of 2.4 × 10(11) EDTA molecules. In total, 75 gram EDTA needs to be injected to remove all the column sites.

Yang X; Liang D; Deng S

2012-09-01

135

Carbon adsorbents from shale phenols  

Energy Technology Data Exchange (ETDEWEB)

The article describes the preparation of adsorbents from shale phenols, their properties and applications. Highly effective microporous adsorbents have been produced, with high sorption indices. New adsorbents can be useful for the purpose of air purification, maintaining the required temperatures in food storage facilities, as well as treating gaseous and liquid wastes from nuclear plant. 5 refs., 7 tabs.

Pokonova, Y.V. [St. Petersburg Technological Institute, St. Petersburg (Russian Federation)

1996-06-01

136

Study on the development of the adsorbent for extraction of uranium from seawater  

International Nuclear Information System (INIS)

The extraction of uranium from seawater involves adsorption, desorption, concentration and separation, of which the adsorption stage requires most development; uranium concentration in seawater is very low, its amount handled being extremely large. The authors have developed a metal-containing hydroxide - active carbon composite adsorbent and an AO resin adsorbent for uranium extraction from seawater. The following are described: the development of inorganic adsorbents - the preparation of a metal-containing hydroxide - active carbon adsorbent, the forming of a titanium - active carbon composite adsorbent, the extraction of uranium from seawater with a composite adsorbent; the development of organic adsorbents - the preparation of AO resin and uranium adsorption; the extraction of uranium from seawater with AO resin, the preparation of fibrous and bead-fibrous AO resin. (Mori, K.).

1987-01-01

137

Sand consolidation methods using adsorbable catalysts  

Energy Technology Data Exchange (ETDEWEB)

Methods are provided for selectively consolidating sand grains within a subterranean formation. First an acidic zirconium salt catalyst, such as ZrOCl/sub 2/, Zr(SO/sub 4/)/sub 2/, or ZrCl/sub 4/, is injected into the subterranean formation, wherein the acidic salt catalyst is adsorbed to the surface of the sand grains. Next a polymerizable resin composition such as furfuryl alcohol oligomer is introduced into the well formation. Polymerization of the resin occurs upon exposure to the elevated well temperatures and contact with the acid salt catalyst adsorbed to the sand grains. The polymerized resin serves to consolidate the surfaces of the sand grains while retaining permeability through the pore spaces. An ester of a weak organic acid is included with the resin compositions to control the extent of a polymerization by consuming the water by-product formed during the polymerization reaction.

Friedman, R. H.

1985-04-23

138

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

Scientific Electronic Library Online (English)

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

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

2005-08-01

139

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

Energy Technology Data Exchange (ETDEWEB)

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

Shirato, Wataru.

1993-03-19

140

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

International Nuclear Information System (INIS)

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

1991-12-12

 
 
 
 
141

Neutron scattering from adsorbed species  

International Nuclear Information System (INIS)

Neutron reflection has been used to investigate the structure of layers of water-soluble diblock copolymers poly(2-(dimethylamino)ethyl methacrylate-block-methyl methacrylate (poly(DMAEMA-b-MMA)) (70 mol% DMAEMA, Mn = 10k, 80 mol% DMAEMA, Mn = 10k, and 70 mol% DMAEMA, Mn = 20k) adsorbed at the air-liquid and solid-liquid interfaces. The surface tension behaviour of these copolymers at the air-liquid interface has also been investigated. The study of the structure of layers of poly(DMAEMA-b-MMA) adsorbed at the air-water interface forms the main part of the thesis. The surface structure, the effects of pH and ionic strength, and the effects of composition and molecular weight of the copolymers have been studied systematically. For the 70%-10k copolymer at pH 7.5, the adsorption isotherm shows that there is a surface phase transition. The concentration of copolymer at which the phase transition occurs is close to that at which micellar aggregation in the bulk solution also occurs. At low concentrations (below the CMC), the two blocks of the copolymer are approximately uniformly distributed in the direction normal to the interface and the layer is partially immersed in water. At high concentrations (above the CMC), the adsorbed layer has a cross-sectional structure resembling that expected for a micelle with the majority of the MMA blocks forming the core. The outer layers, comprising predominantly DMAEMA blocks, are not equivalent, being more highly extended on the aqueous side of the interface. The effects of pH and added electrolyte on the structure of layers of the 70%-10k copolymer show that the layered structure is promoted by any changes in the bulk solution that enhance the surface coverage but is inhibited by an increase in the fractional charge on the polyelectrolyte part of the copolymer. The effect of lowering the pH is to increase the positive charge on the weak polyelectrolyte block. Addition of electrolyte generally enhances the amount adsorbed and shifts the transition to the layered surface structure to lower bulk copolymer concentrations. Changes in composition and molecular weight of the copolymers show that the copolymers 80%-10k and 70%-20k form the same surface structures as 70%-10k. The 80%-10k copolymer is more surface active than 70%-10k copolymer and this parallels the tendency to aggregate into micelles in bulk solution. The increase in molecular weight from 10k to 20k decreases the surface activity of the 70% DMAEMA copolymer. The effects of pH and added electrolyte on the structure of a weak polyelectrolyte brush anchored by means of a hydrophobic block to a hydrophobic surface were studied. The copolymer was 70%-10k and the hydrophobic surface was a self-assembled monolayer of octadecyl trichlorosilane (OTS) on silicon surface. The MMA block was found to bind strongly and irreversibly to the OTS layer. The copolymer distribution could be described in terms of two uniform layers, a thin, dense layer next to the OTS surface containing all the MMA block and variable amounts of the DMAEMA segment, and a. more diffuse DMAEMA layer corresponding to the polyelectrolyte brush. The presence of the DMAEMA segment in the thin layer and the variation of this amount with pH and added electrolyte show that the region near the anchor layer of the MMA block is not ionized, in agreement with the model of a grafted weak polyelectrolyte proposed by Israels et al. (author)

1998-01-01

142

Neutron scattering from adsorbed species  

Energy Technology Data Exchange (ETDEWEB)

Neutron reflection has been used to investigate the structure of layers of water-soluble diblock copolymers poly(2-(dimethylamino)ethyl methacrylate-block-methyl methacrylate (poly(DMAEMA-b-MMA)) (70 mol% DMAEMA, M{sub n} = 10k, 80 mol% DMAEMA, M{sub n} = 10k, and 70 mol% DMAEMA, M{sub n} = 20k) adsorbed at the air-liquid and solid-liquid interfaces. The surface tension behaviour of these copolymers at the air-liquid interface has also been investigated. The study of the structure of layers of poly(DMAEMA-b-MMA) adsorbed at the air-water interface forms the main part of the thesis. The surface structure, the effects of pH and ionic strength, and the effects of composition and molecular weight of the copolymers have been studied systematically. For the 70%-10k copolymer at pH 7.5, the adsorption isotherm shows that there is a surface phase transition. The concentration of copolymer at which the phase transition occurs is close to that at which micellar aggregation in the bulk solution also occurs. At low concentrations (below the CMC), the two blocks of the copolymer are approximately uniformly distributed in the direction normal to the interface and the layer is partially immersed in water. At high concentrations (above the CMC), the adsorbed layer has a cross-sectional structure resembling that expected for a micelle with the majority of the MMA blocks forming the core. The outer layers, comprising predominantly DMAEMA blocks, are not equivalent, being more highly extended on the aqueous side of the interface. The effects of pH and added electrolyte on the structure of layers of the 70%-10k copolymer show that the layered structure is promoted by any changes in the bulk solution that enhance the surface coverage but is inhibited by an increase in the fractional charge on the polyelectrolyte part of the copolymer. The effect of lowering the pH is to increase the positive charge on the weak polyelectrolyte block. Addition of electrolyte generally enhances the amount adsorbed and shifts the transition to the layered surface structure to lower bulk copolymer concentrations. Changes in composition and molecular weight of the copolymers show that the copolymers 80%-10k and 70%-20k form the same surface structures as 70%-10k. The 80%-10k copolymer is more surface active than 70%-10k copolymer and this parallels the tendency to aggregate into micelles in bulk solution. The increase in molecular weight from 10k to 20k decreases the surface activity of the 70% DMAEMA copolymer. The effects of pH and added electrolyte on the structure of a weak polyelectrolyte brush anchored by means of a hydrophobic block to a hydrophobic surface were studied. The copolymer was 70%-10k and the hydrophobic surface was a self-assembled monolayer of octadecyl trichlorosilane (OTS) on silicon surface. The MMA block was found to bind strongly and irreversibly to the OTS layer. The copolymer distribution could be described in terms of two uniform layers, a thin, dense layer next to the OTS surface containing all the MMA block and variable amounts of the DMAEMA segment, and a. more diffuse DMAEMA layer corresponding to the polyelectrolyte brush. Thepresence of the DMAEMA segment in the thin layer and the variation of this amount with pH and added electrolyte show that the region near the anchor layer of the MMA block is not ionized, in agreement with the model of a grafted weak polyelectrolyte proposed by Israels et al. (author)

Shuwang An

1998-07-01

143

Thermal decomposition of methanol adsorbed on alumina  

International Nuclear Information System (INIS)

[en] The kinetic behavior of methanol adsorbed on alumina powder was studied by thermal desorption and isotopic tracer techniques using an ultrahigh vacuum system. Several products were desorbed; CH3OH is predominant at low temperatures, H2CO, H2O, and CH3OCH3 become significant at 5000K and higher, CO and CH4 are observed above 7000K (CO predominates), H2 is desorbed at both low and high temperatures peaking with H2CO and CO, and finally CO2 is observed in small amounts at all temperatures. The isotopic composition of ethers desorbed after coadsorption of CH3OH and CD3OD was investigated. Below 5000K, only CH3OCH3, CD3OCH3, and CD3OCD3 appeared, while above this temperature the deuterium in ethers approached a random distribution. From this result it is concluded that below 5000K, adsorbed methanol (methoxide) is stable with respect to hydrogen exchange whereas at higher temperatures the H for D exchange is facile. In the presence of gas phase CD3OD, thermal desorption was examined from CH3OH-preadsorbed substrate. The ether produced was primarily CH3OCH3 suggesting that ether is formed through the interaction of two adsorbed methoxides. The reactivity of adsorbed methoxides is discussed and it is suggested that heterogeneity is induced by adsorption and/or desorption

1976-01-01

144

Fretting wear behaviour of microarc oxidation coatings formed on titanium alloy against steel in unlubrication and oil lubrication  

Science.gov (United States)

Ceramic coatings were formed on Ti6Al4V alloy surface by microarc oxidation (MAO) in a Na2SiO3 system solution. Unlubricated, smear oil and oil bath lubricated fretting tests were performed on MAO coatings against 52100 steel on a fretting wear tester. Microstructural investigation of the worn surfaces was performed and the wear mechanisms were studied. The results show that the coatings are mainly composed of rutile and a small amount of anatase TiO2, both in nano grain structure. Friction coefficient of microarc oxidation coatings under oil bath lubrication was significantly reduced, favorable stable at 0.15, which indicates that the coatings with oil lubricated lowered the shear and adhesive stresses between contact surfaces, consequently alleviating the possibility of initiation and propagation of cracks in the inner layer of the coating or titanium alloy substrate.

Wang, Yaming; Lei, Tingquan; Guo, Lixin; Jiang, Bailing

2006-09-01

145

Influence of albumin and inorganic ions on electrochemical corrosion behavior of plasma electrolytic oxidation coated magnesium for surgical implants  

Science.gov (United States)

Magnesium and its alloys are of great interest for biodegradable metallic devices. However, the degradation behavior and mechanisms of magnesium treated with coating in physiological environment in the presence of organic compound such as albumin have not been elucidated. In this study, the plasma electrolytic oxidation coated magnesium immersed in four different simulated body fluids: NaCl, PBS and with the addition of albumin to investigate the influence of protein and inorganic ions on degradation behavior by electrochemical methods. The results of electrochemical tests showed that aggressive corrosion took place in 0.9 wt.% NaCl solution; whereas albumin can act as an inhibitor, its adsorption impeded further dissolution of the coating. The mechanism was attributed to the synergistic effect of protein adsorption and precipitation of insoluble salts.

Wan, Peng; Lin, Xiao; Tan, LiLi; Li, Lugee; Li, WeiRong; Yang, Ke

2013-10-01

146

Sorptive removal of cobalt, strontium and cesium onto manganese and iron oxide-coated montmorillonite from groundwater  

International Nuclear Information System (INIS)

Applicability of montmorillonite, manganese oxide-coated montmorillonite (MOCM) and iron oxide-coated montmorillonite (IOCM) as backfill materials in permeable reactive barrier (PRB) to remediate contaminated groundwater was investigated. Single- and bi-solute competitive sorptions of Co, Sr and Cs were conducted. The Freundlich, Langmuir and Dubinin-Radushkevich models fitted the single-solute sorption data well (R2 > 0.95). Maximum sorption capacities (qmL) of Co and Sr predicted by the Langmuir model were in the order of MOCM (0.37 mmol/g for Co and 0.28 mmol/g for Sr) > montmorillonite (0.27 mmol/g for Co and 0.19 mmol/g for Sr) ? IOCM (0.23 mmol/g for Co and 0.21 mmol/g for Sr), while those of Cs were in the order of montmorillonite (1.11 mmol/g) > MOCM (0.68 mmol/g) > IOCM (0.62 mmol/g). In the bi-solute sorptions, the sorbed amount of one solute decreased due to the presence of the other competing metal ion. Langmuir model parameters for single-solute (qmL and bL) and bi-solute (qmL* and bL*) sorptions were compared to analyze the effect of competition between the metal ions. The competitive Langmuir (R2 > 0.81) and P-factor (R2 > 0.82) models predicted the bi-solute competitive sorption data well but not the SRS model (0.003 2

2012-01-01

147

High performance Mo adsorbent PZC  

Energy Technology Data Exchange (ETDEWEB)

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

Anon.

1998-10-01

148

Container for shipment of adsorbents  

International Nuclear Information System (INIS)

A container is designed for the transport of granulated saturated adsorbents from the treatment of radioactive waste waters from nuclear power plants. The body of the container provided with a lid contains a collecting vessel consisting of a jacket with perforated bottom. In the upper part of the container there is a feeder for the adsorbent suspension. Water from the dewatered adsorbent is discharged under the perforated bottom of the collecting vessel and flows through the container lid. The design allows remote control of the adsorbent and concentrate filling and emptying of the container. (J.C.)

1983-01-13

149

Positronium chemistry in porous adsorbents  

International Nuclear Information System (INIS)

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

1981-04-16

150

Silicon effects on formation of EPO oxide coatings on aluminum alloys  

International Nuclear Information System (INIS)

Electrolytic plasma processes (EPP) can be used for cleaning, metal-coating, carburizing, nitriding, and oxidizing. Electrolytic plasma oxidizing (EPO) is an advanced technique to deposit thick and hard ceramic coatings on a number of aluminum alloys. However, the EPO treatment on Al-Si alloys with a high Si content has rarely been reported. In this research, an investigation was conducted to clarify the effects of silicon contents on the EPO coating formation, morphology, and composition. Cast hypereutectic 390 alloys (? 17% Si) and hypoeutectic 319 alloys (? 7% Si) were chosen as substrates. The coating morphology, composition, and microstructure of the EPO coatings on those substrates were investigated using scanning electron microscopy (SEM) with energy dispersive X-ray (EDX) analysis and X-ray diffraction (XRD). A stylus roughness tester was used for surface roughness measurement. It was found that the EPO process had four stages where each stage was corresponding to various coating surface morphology, composition, and phase structures, characterised by different coating growth mechanisms

2006-01-03

151

Silicon effects on formation of EPO oxide coatings on aluminum alloys  

Energy Technology Data Exchange (ETDEWEB)

Electrolytic plasma processes (EPP) can be used for cleaning, metal-coating, carburizing, nitriding, and oxidizing. Electrolytic plasma oxidizing (EPO) is an advanced technique to deposit thick and hard ceramic coatings on a number of aluminum alloys. However, the EPO treatment on Al-Si alloys with a high Si content has rarely been reported. In this research, an investigation was conducted to clarify the effects of silicon contents on the EPO coating formation, morphology, and composition. Cast hypereutectic 390 alloys ({approx} 17% Si) and hypoeutectic 319 alloys ({approx} 7% Si) were chosen as substrates. The coating morphology, composition, and microstructure of the EPO coatings on those substrates were investigated using scanning electron microscopy (SEM) with energy dispersive X-ray (EDX) analysis and X-ray diffraction (XRD). A stylus roughness tester was used for surface roughness measurement. It was found that the EPO process had four stages where each stage was corresponding to various coating surface morphology, composition, and phase structures, characterised by different coating growth mechanisms.

Wang, L. [Department of Mechanical, Automotive and Materials Engineering, University of Windsor, Windsor, ON, N9B 3P4 (Canada); Nie, X. [Department of Mechanical, Automotive and Materials Engineering, University of Windsor, Windsor, ON, N9B 3P4 (Canada)]. E-mail: xnie@uwindsor.ca

2006-01-03

152

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

UK PubMed Central (United Kingdom)

We describe laboratory and field results of a novel arsenic removal adsorbent called 'Arsenic Removal Using Bottom Ash' (ARUBA). ARUBA is prepared by coating particles of coal bottom ash, a waste material from coal fired power plants, with iron (hydr)oxide. The coating process is simple and conducted at room temperature and atmospheric pressure. Material costs for ARUBA are estimated to be low (approximately $0.08 per kg) and arsenic remediation with ARUBA has the potential to be affordable to resource-constrained communities. ARUBA is used for removing arsenic via a dispersal-and-removal process, and we envision that ARUBA would be used in community-scale water treatment centers. We show that ARUBA is able to reduce arsenic concentrations in contaminated Bangladesh groundwater to below the Bangladesh standard of 50 ppb. Using the Langmuir isotherm (R(2) = 0.77) ARUBA's adsorption capacity in treating real groundwater is 2.6 x 10(- 6)mol/g (0.20 mg/g). Time-to-90% (defined as the time interval for ARUBA to remove 90% of the total amount of arsenic that is removed at equilibrium) is less than 1 hour. Reaction rates (pseudo-second-order kinetic model, R(2) > or = 0.99) increase from 2.4 x 10(5) to 7.2 x 10(5) g mol(- 1)min(- 1) as the groundwater arsenic concentration decreases from 560 to 170 ppb. We show that ARUBA's arsenic adsorption density (AAD), defined as the milligrams of arsenic removed at equilibrium per gram of ARUBA added, is linearly dependent on the initial arsenic concentration of the groundwater sample, for initial arsenic concentrations of up to 1600 ppb and an ARUBA dose of 4.0 g/L. This makes it easy to determine the amount of ARUBA required to treat a groundwater source when its arsenic concentration is known and less than 1600 ppb. Storing contaminated groundwater for two to three days before treatment is seen to significantly increase ARUBA's AAD. ARUBA can be separated from treated water by coagulation and clarification, which is expected to be less expensive than filtration of micron-scale particles, further contributing to the affordability of a community-scale water treatment center.

Mathieu JL; Gadgil AJ; Addy SE; Kowolik K

2010-09-01

153

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

Energy Technology Data Exchange (ETDEWEB)

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

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

2010-06-01

154

Iron oxide coating films in soda-lime glass by triboadhesion  

Energy Technology Data Exchange (ETDEWEB)

In the triboadhesion process the coating material is passed through a rotating cotton mop and the substrate to be coated. The cotton mop rotates at high velocity and exerts pressure on the surface of the substrate. The combined effect of pressure and velocity of the coating mop on the substrate increases its temperature close to the melting point, allowing deposition and diffusion of the coating material within the substrate. After it is deposited, its particles are embedded within the base material forming a thin film composite. The amount of the coating material deposited on the substrate has its maximum at the surface and then decreases as a function of the local temperature within the base material. Bearing this in mind, in the present work, triboadhesion is employed to deposit iron oxide in a substrate of soda-lime glass, with the purpose of determining the feasibility of using this technique for solar control coatings. It was found, through electronic scan microscopy, that a composite material film is formed following the coating direction. Reflectance and transmittance tests were carried out on the glass samples. A 20% difference was found in the visible spectral region (VIS), and a reduction between 10 and 20% in the Near Infrared Region (NIR). These results showed that the triboadhesion is a promising technique for the application of thin films for solar control or solar cells

Aguilar, J. O.; Arjona, M. J. [Boulevard Bahia s/n esq. Ignacio Comonfort, Chetumal (Mexico); Rodriguez-Lelis, J. M. [Interior Internado Palmira s/n, Cuernavaca, Morelos (Mexico)

2009-04-15

155

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

International Nuclear Information System (INIS)

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

2006-07-25

156

Polyacrylate adsorbents for the selective adsorption of cholesterol-rich lipoproteins from plasma or blood.  

UK PubMed Central (United Kingdom)

Polyacrylate (PAA) adsorbents selectively bind low density lipoproteins (LDL) from human plasma and blood, whereas very low density lipoproteins (VLDL) are only minimally adsorbed. The adsorption of cholesterol-rich lipoproteins to PAA adsorbents is related to the molecular weight (mw) of the polyanion ligand. Ca(++) and Mg(++) inhibit the binding of LDL to PAA adsorbents. The chemical composition of the organic hardgels of the adsorbents does not have an influence on adsorption. The selective adsorption of LDL to PAA adsorbents can be explained to result from their low negative surface charge density and the specific colloid-chemical properties of the surface-bound PAA, which do not prevent LDL from binding to charge-like domains of the ligand. By contrast, VLDL and high density lipoproteins (HDL) are repelled from the adsorbents due to their higher negative surface charge density.

Heuck CC

2011-01-01

157

Polyacrylate adsorbents for the selective adsorption of cholesterol-rich lipoproteins from plasma or blood  

Directory of Open Access Journals (Sweden)

Full Text Available Polyacrylate (PAA) adsorbents selectively bind low density lipoproteins (LDL) from human plasma and blood, whereas very low density lipoproteins (VLDL) are only minimally adsorbed. The adsorption of cholesterol-rich lipoproteins to PAA adsorbents is related to the molecular weight (mw) of the polyanion ligand. Ca++ and Mg++ inhibit the binding of LDL to PAA adsorbents. The chemical composition of the organic hardgels of the adsorbents does not have an influence on adsorption. The selective adsorption of LDL to PAA adsorbents can be explained to result from their low negative surface charge density and the specific colloid-chemical properties of the surface-bound PAA, which do not prevent LDL from binding to charge-like domains of the ligand. By contrast, VLDL and high density lipoproteins (HDL) are repelled from the adsorbents due to their higher negative surface charge density.

Heuck, Claus-Chr.

2011-01-01

158

Evaluation of cerium oxide coated Cu cermets as inert anodes for aluminum electrowinning. Final report, August 1990--March 1992  

Energy Technology Data Exchange (ETDEWEB)

Cu/NiFe{sub 2}O{sub 4} cermets were evaluated, with and without an in-situ deposited CEROX (TM; cerium oxide) coating, in 100 h laboratory A1 electrowinning tests. Bath ratio and current density were varied between tests and corrosion was determined by contamination of the aluminum and cryolite by cermet components (Cu, Fe, and Ni). Higher bath ratios of 1.5 to 1.6 led to less corrosion and thicker CEROX coatings. Lower current densities led to slightly less corrosion but much less oxidation of the Cu cermet substrate. At identical test conditions, the corrosion of the CEROX coated cermets was 1/7 that of an uncoated cermet. Corrosion was increased in CEROX coated cermets tested under unsaturated alumina conditions. The electrical conductivity of the CEROX coating was measured to be {approximately}0.2 ohm{sup {minus}1}cm{sup {minus}1}, resulting in a slight voltage penalty, depending on the thickness of the coating.

1992-08-01

159

Carbon adsorbents from petroleum residues  

Energy Technology Data Exchange (ETDEWEB)

Data are presented on utilizing petroleum asphaltite as an addition to the charge and as a binder when producing adsorbents and also on the products of their thermal and chemical modification. Highly effective microporous adsorbents have been produced whose sorption indices are higher than industrial ones. They may be used as carriers of hemosorbents, clarifying carbons, and for selective isolation of the noble metals from multicomponent solutions. The new adsorbents may be useful for air purification in rooms, for keeping the required temperature in food storage, as well as for cleaning nuclear power plant gas effluents. (Author).

Pokonova, Yu.V. (Lensoviet Inst. of Technology, Leningrad (USSR))

1991-01-01

160

Carbon adsorbents from petroleum residues  

International Nuclear Information System (INIS)

[en] Data are presented on utilizing petroleum asphaltite as an addition to the charge and as a binder when producing adsorbents and also on the products of their thermal and chemical modification. Highly effective microporous adsorbents have been produced whose sorption indices are higher than industrial ones. They may be used as carriers of hemosorbents, clarifying carbons, and for selective isolation of the noble metals from multicomponent solutions. The new adsorbents may be useful for air purification in rooms, for keeping the required temperature in food storage, as well as for cleaning nuclear power plant gas effluents. (Author)

1991-01-01

 
 
 
 
161

Antimony doped tin oxide coating of muscovite clays by the Pechini route  

International Nuclear Information System (INIS)

[en] The preparation of antimony doped tin oxide (ATO) conductive thin films on mica (muscovite) clays is described. ATO coating solution was prepared from ethylene glycol monomer, citric acid ligand, SbCl3 and SnCl2 precursors in alcohol solution. Muscovite thin film coating was prepared by gradual addition of the precursor solution to a water-muscovite clay dispersion. Under appropriate precursor concentrations and temperature, aggregation of the clays and ATO particles was prevented, and the ATO film grew exclusively on the clay substrate. Heat treatment of the coated mica resulted in semi transparent and conductive clays which could be used for composite film formation. Whereas the Pechini route is widely used for dip coating of ATO films, here we extend the approach for coating particulate matter. The films were characterized by electronic microscopy, X-ray photoelectron spectroscopy, powder diffraction, and thermal analysis and the dependence of conductivity on calcination temperature and precursor concentrations are described.

2011-10-31

162

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

UK PubMed Central (United Kingdom)

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

Pan YK; Chen CZ; Wang DG; Yu X

2012-08-01

163

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

International Nuclear Information System (INIS)

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

2009-02-27

164

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

Science.gov (United States)

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

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

2013-01-01

165

FORMED OBJECT ADSORBING HAZARDOUS SUBSTANCE  

UK PubMed Central (United Kingdom)

A multifunctional formed object containing an adsorbent for hazardous substances is provided in the form of a water-soluble sheet or tablet. The formed object comprises a hazardous-substance-adsorbing formed object having a multiple function imparted thereto, and can be applied to a contaminated environment while preventing a fine powder from flying off or causing dust explosion and without necessitating much labor. After application, the formed object adsorptively fixes thereto a hazardous substance present in the contaminated environment. The hazardous

EUN HEESOO; FUKUI HIROAKI

166

Synthesis, Novel adsorbents, Pollutants, Wastewater, Kinetics, Equilibrium Study  

Directory of Open Access Journals (Sweden)

Full Text Available Increased industrial, agricultural and domestic activities have resulted in adding large amount of wastewater, containing a number of toxic pollutants, to the available fresh water resources. The presence of toxic pollutants adversely affects human and animal life and cause environmental pollution. This realization has placed pollution control and management, the most challenging task for researchers and practitioners worldwide. In Pakistan surface and ground water are mainly polluted from the byproducts of various industries including textile, metal, dying, chemicals, pharmaceutical, leather, pesticides, sugar processing and others. Industrial effluents and municipal water ultimately reaches to the rivers carried by drains and canals thus worsen the water pollution. It is reported that 60 % population of developing counties have no access to safe drinking water. The present research is an attempt to remove nitrates and phenols pollutants present in the aqueous media with the synthesized novel adsorbents. The aqueous samples include industrial effluents collected from 09 different industries of the Punjab. Each composite aqueous sample was characterized to determine the background concentration of nitrates and phenols. Nanoparticles of alumina were synthesized using different standardized methods with slight modifications to present novel materials for the removal of pollutants. In addition, meso alumina procured from Merck was applied as adsorbent for comparison with synthesized alumina particles. The results indicated higher concentrations of Nitrates and Phenols in the aqueous samples. The characterization also highlights that Tanneries can be regarded as the most polluted industry among other industrial units. The selected meso and synthesized alumina materials were applied as adsorbents in batch experiments. For this purpose, twelve series of batch experiment was conducted at variables of contact time, pH of the medium, adsorbent dose and adsorbate concentration. The data showed that adsorption on meso and nano materials is a time efficient process as two or more equilibrium is attained on contact of 30 minutes only. The rapid adsorption of nitrates by meso and nano adsorbents is attributed to the external surface adsorption, which is different from the micro porous adsorption process. It is interesting to note that exactly opposite sequence commands the removal of phenols and nitrates, both for meso adsorbents and nano adsorbents as well. Nano Alumina (AL2) being the poorer for nitrates among nano adsorbents take the lead for phenols removal. Furthermore, the meso adsorbents on average had proven as good adsorbents under all pH ranges. The application of Langmuir, Freundlich and Temkin models are found equally good for all adsorbents, whereas pseudo 2nd order kinetics is in best agreement with the experimental data.

Nasreen S.; Rafique U.

2012-01-01

167

Instability of waste plumes adsorbed on iron oxide in soils  

International Nuclear Information System (INIS)

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

1987-01-01

168

Growth and characterization of chromium oxide coatings prepared by pulsed-direct current reactive unbalanced magnetron sputtering  

International Nuclear Information System (INIS)

[en] Approximately 0.2-3.2 ?m thick single phase chromium oxide (Cr2O3) coatings with different oxygen flow rates were deposited on silicon and mild steel substrates at low substrate temperature (?60 deg. C) by pulsed-direct current (DC) reactive unbalanced magnetron sputtering. Two asymmetric bipolar-pulsed DC generators were used to co-sputter two Cr targets, in Ar + O2 plasma. The coatings were characterized using X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), nanoindentation hardness tester, optical microscopy, atomic force microscopy, micro-Raman spectroscopy, spectroscopic ellipsometry and potentiodynamic polarization techniques. The XRD data showed the presence of mixture of crystalline (rhombohedral Cr2O3) and amorphous phases for the coatings prepared with oxygen flow rate less than 10 sccm. A complete transformation to amorphous phase was observed at higher oxygen flow rates. The XRD results were supported by Raman spectroscopy data. The XPS data suggested that the chemical state of Cr was in the form of Cr3+. The chromium oxide coatings exhibited a maximum hardness of 22 GPa and an elastic modulus of 208 GPa. The coatings exhibited high thermal stability upon annealing in vacuum up to 500 deg. C and retained hardness as high as 17 GPa. Spectroscopic ellipsometry data indicated that coatings prepared at higher oxygen flow rates were dielectric in nature and those prepared at low oxygen flow rates exhibited an intermediate character, i.e., a transition between the dielectric and the metallic behavior. The corrosion behavior of Cr2O3 coating deposited on mild steel substrates was investigated using potentiodynamic polarization in 3.5% NaCl solution. The results indicated that Cr2O3 coating exhibited superior corrosion resistance as compared to the uncoated substrate

2008-12-30

169

Treatment of heavy metals by iron oxide coated and natural gravel media in Sustainable urban Drainage Systems.  

Science.gov (United States)

Sustainable urban Drainage Systems (SuDS) filter drains are simple, low-cost systems utilized as a first defence to treat road runoff by employing biogeochemical processes to reduce pollutants. However, the mechanisms involved in pollution attenuation are poorly understood. This work aims to develop a better understanding of these mechanisms to facilitate improved SuDS design. Since heavy metals are a large fraction of pollution in road runoff, this study aimed to enhance heavy metal removal of filter drain gravel with an iron oxide mineral amendment to increase surface area for heavy metal scavenging. Experiments showed that amendment-coated and uncoated (control) gravel removed similar quantities of heavy metals. Moreover, when normalized to surface area, iron oxide coated gravels (IOCGs) showed poorer metal removal capacities than uncoated gravel. Inspection of the uncoated microgabbro gravel indicated that clay particulates on the surface (a natural product of weathering of this material) augmented heavy metal removal, generating metal sequestration capacities that were competitive compared with IOCGs. Furthermore, when the weathered surface was scrubbed and removed, metal removal capacities were reduced by 20%. When compared with other lithologies, adsorption of heavy metals by microgabbro was 10-70% higher, indicating that both the lithology of the gravel, and the presence of a weathered surface, considerably influence its ability to immobilize heavy metals. These results contradict previous assumptions which suggest that gravel lithology is not a significant factor in SuDS design. Based upon these results, weathered microgabbro is suggested to be an ideal lithology for use in SuDS. PMID:23925197

Norris, M J; Pulford, I D; Haynes, H; Dorea, C C; Phoenix, V R

2013-01-01

170

Treatment of heavy metals by iron oxide coated and natural gravel media in Sustainable urban Drainage Systems.  

UK PubMed Central (United Kingdom)

Sustainable urban Drainage Systems (SuDS) filter drains are simple, low-cost systems utilized as a first defence to treat road runoff by employing biogeochemical processes to reduce pollutants. However, the mechanisms involved in pollution attenuation are poorly understood. This work aims to develop a better understanding of these mechanisms to facilitate improved SuDS design. Since heavy metals are a large fraction of pollution in road runoff, this study aimed to enhance heavy metal removal of filter drain gravel with an iron oxide mineral amendment to increase surface area for heavy metal scavenging. Experiments showed that amendment-coated and uncoated (control) gravel removed similar quantities of heavy metals. Moreover, when normalized to surface area, iron oxide coated gravels (IOCGs) showed poorer metal removal capacities than uncoated gravel. Inspection of the uncoated microgabbro gravel indicated that clay particulates on the surface (a natural product of weathering of this material) augmented heavy metal removal, generating metal sequestration capacities that were competitive compared with IOCGs. Furthermore, when the weathered surface was scrubbed and removed, metal removal capacities were reduced by 20%. When compared with other lithologies, adsorption of heavy metals by microgabbro was 10-70% higher, indicating that both the lithology of the gravel, and the presence of a weathered surface, considerably influence its ability to immobilize heavy metals. These results contradict previous assumptions which suggest that gravel lithology is not a significant factor in SuDS design. Based upon these results, weathered microgabbro is suggested to be an ideal lithology for use in SuDS.

Norris MJ; Pulford ID; Haynes H; Dorea CC; Phoenix VR

2013-01-01

171

FERTILIZER COMPOSITION  

UK PubMed Central (United Kingdom)

A pelletized fertilizer composition is provided which includes at least one active ingredient selected from urea, monoammonium phosphate (MAP), diammonium phosphate (DAP), potassium chloride and potassium sulphate. The composition is characterised in that it further includes charcoal onto which the at least one active ingredient is at least partially adsorbed, and it excludes potassium nitrate and ammonium nitrate.

ROZANOV ANDREI BORISOVICH; HARDIE AILSA GHILLAINE

172

Krypton retention on solid adsorbents  

International Nuclear Information System (INIS)

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 (-400 to -800C). Silver mordenite has a higher capacity for krypton retention, but is 50 times more expensive than hydrogen mordenite

1982-01-01

173

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

International Nuclear Information System (INIS)

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

1992-12-24

174

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

Energy Technology Data Exchange (ETDEWEB)

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

Wollrich, G.W.

1994-07-07

175

Method of processing spent adsorbents  

International Nuclear Information System (INIS)

Purpose: To make spent adsorbents combustible and prevent the dispersion of adsorbed substance upon combustion. Method: Organic compounds such as saccharides are adsorbed saturately on activated carbon or ion exchange resins. Further, saccharides are additionally incorporated, kneaded and dried into a block form. Then, they are burnt. For instance, after adding an aqueous 1% solution of sucrose by 0.5 liter per 1 kg of the activated carbon and uniformly kneading, they are dried at 1200C for about one hour. Subsequently, 0.5 liter of an aqueous 10% solution of sucrose are added, uniformly kneaded and dried at 1200C for about one hour into a block form. Upon igniting with burner, they can be combusted spontaneously with no flames to leave only metal-oxide cinders. The saccharides can be replaced with starches or gum arabic. If the concentration of the saccharides to be added is high, although the combustion velocity is increased, the risk of dispersing adsorbed substances may be resulted. (Ikeda, J.).

1982-05-12

176

Effects of adsorbates on submonolayer growth  

CERN Multimedia

The effects of adsorbates on nucleation and growth of two-dimensional islands is investigated by kinetic Monte Carlo simulations and rate equation theory. The variation of island morphology with adsorbate parameters is discussed and the temperature-dependence of island density in the case of immobile adsorbates is studied in detail. A set of rate equations for the description of nucleation in the presence of predeposited mobile and immobile adsorbates is developed.

Kotrla, M; Smilauer, P; Kotrla, Miroslav; Krug, Joachim; Smilauer, Pavel

2001-01-01

177

COMPOSITIONS  

UK PubMed Central (United Kingdom)

A fat continuous confectionery composition comprises less than 2% by weight of a fermentable sugar, and a sweetening component in an amount of at least 25% by weight of the composition. The sweetening component comprises at least 50% by weight non-hydrogenated isomaltulose and may also comprise at least 5% by weight inulin, dextrin or a mixture of inulin and dextrin. The composition may comprise milk or whey protein in an amount of between 1 and 10% by weight of the composition.

DE BROUWER MARIJKE; DERYCKE VEERLE

178

Development of new molybdenum adsorbent  

International Nuclear Information System (INIS)

[en] Neutron Irradiation and Testing Reactor Center has developed for production of medical isotope of 99Mo, the parent nuclide of 99mTc by the (n, ?) method use JMTR. The (n, ?) method has an advantage of easy manufacturing process and low radioactive wastes generation. However, the low radioactivity concentration of 99mTc is remaining as an issue. Therefore, PZC was developed as adsorbent of molybdenum. However, PZC has some faults. So, new adsorbent based on titanium (PTC), was developed for getting rid of faults. This time, 99Mo adsorption and 99mTc elution tests with PZC and PTC were carried out. As a result, the 99Mo adsorption performance of the PTC was lower than PZC, on the other hand, 99mTc elution performance of the PTC was higher than PZC. (author)

2011-01-01

179

Radiolysis methanol adsorbed on zeolite  

Energy Technology Data Exchange (ETDEWEB)

Radiolysis of methanol adsorbed on synthesized zeolite was investigated by means of product analysis. Molecular hydrogen, formaldehyde, and ethylene glycol are produced as major products. The G-value for the formation of H/sub 2/ increases with increasing amount of methanol adsorbed on zeolite and approaches ca. 2.1 at about 10/sup -2/ mol of methanol per g of zeolite, where the coverage of methanol is approximately unity and G-values of ca. 1.0 are observed for formaldehyde and ethylene glycol. Addition of an electron scavenger causes decrease in G(H/sub 2/). However, the hydrogen formation is not completely suppressed by N/sub 2/O, SF/sub 6/, or CCl/sub 4/. Kinetics in solution is useful for the interpretation of results and allows the estimation of the G-value for the generation of electron in zeolite and of its relative reactivity toward methanol and some electron scavengers.

Nakazato, Chiyoko; Murayama, Ryoji; Aoki, Masayoshi; Masuda, Takahiro

1987-08-01

180

METALLIC COMPOSITE AND COMPOSITION THEREOF  

UK PubMed Central (United Kingdom)

A metallic composite in which a conjugated compound having a molecular weight of 200 or more is adsorbed to a metallic nanostructure having an aspect ratio of 1.5 or more, for example, a metallic composite in which a compound having a group represented by the formula (I) or a repeating unit represented by the formula (II) or both of them is adsorbed to a metallic nanostructure having an aspect ratio of 1.5 or more, is useful for electronic devices such as a light-emitting device, a solar cell and an organic transistor.

HIGASHIMURA HIDEYUKI; IIJIMA TAKAYUKI; FUJIOKA MASAHIRO; TANAKA KENTA

 
 
 
 
181

Method And Apparatus For Regenerating Nox Adsorbers  

Energy Technology Data Exchange (ETDEWEB)

Methods and apparatuses for regenerating a NOx adsorber coupled with an exhaust of an engine. An actuator drives a throttle valve to a first position when regeneration of the NOx adsorber is desired. The first position is a position that causes the regeneration of the NOx adsorber. An actuator drives the throttle valve to a second position while regeneration of the NOx adsorber is still desired. The second position being a position that is more open than the first position and operable to regenerate a NOx adsorber.

Driscoll, J. Joshua (Dunlap, IL); Endicott, Dennis L. (Peoria, IL); Faulkner, Stephen A. (Stamford, GB); Verkiel, Maarten (Metamora, IL)

2006-03-28

182

Compositeness  

International Nuclear Information System (INIS)

In view of near future pp-bar, e/sup +/e/sup -/ and ep experiments with a reach for new particles up to 0(1 TeV), the interest in schemes with composite W/sup +-/ and Z bosons ins revived. Their viability is ascertained and a case study of a composite isoscalar partner with mass ? 250 Gev is reviewed. Particular emphasis is given to the strongly coupled standard model which predicts a rich spectrum of composite isoscalar bosons, among them color octet bosons, leptoquarks, dileptons and colored diquarks with masses ? 0(1 TeV). Their signatures in pp-bar reactions are detailed. As main recent activity in composite model building, the author views the composite Higgs mechanism, distinguished by a composite (pseudo-) Goldstone boson Higgs with an essentially calculable mass of the order of 200 GeV.

1986-07-04

183

Nitric oxide releasing material adsorbs more fibrinogen.  

UK PubMed Central (United Kingdom)

One mechanism of the failure of blood-contacting devices is clotting. Nitric oxide (NO) releasing materials are seen as a viable solution to the mediation of surface clotting by preventing platelet activation; however, NO's involvement in preventing clot formation extends beyond controlling platelet function. In this study, we evaluate NO's effect on factor XII (fibrinogen) adsorption and activation, which causes the initiation of the intrinsic arm of the coagulation cascade. This is done by utilizing a model plasticized poly(vinyl) chloride (PVC), N-diazeniumdiolate system and looking at the adsorption of fibrinogen, an important clotting protein, to these surfaces. The materials have been prepared in such a way to eliminate changes in surface properties between the control (plasticized PVC) and composite (NO-releasing) materials. This allows us to isolate NO release and determine the effect on the adsorption of fibrinogen, to the material surface. Surprisingly, it was found that an NO releasing material with a surface flux of 17.4 ± 0.5 × 10(-10) mol NO cm(-2) min(-1) showed a significant increase in the amount of fibrinogen adsorbed to the material surface compared to one with a flux of 13.0 ± 1.6 × 10(-10) mol NO cm(-2) min(-1) and the control (2334 ± 496, 226 ± 99, and 103 ±31% fibrinogen adsorbed of control, respectively). This study suggests that NO's role in controlling clotting is extended beyond platelet activation. © 2013 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 101A: 3201-3210, 2013.

Lantvit SM; Barrett BJ; Reynolds MM

2013-11-01

184

Nitric oxide releasing material adsorbs more fibrinogen.  

Science.gov (United States)

One mechanism of the failure of blood-contacting devices is clotting. Nitric oxide (NO) releasing materials are seen as a viable solution to the mediation of surface clotting by preventing platelet activation; however, NO's involvement in preventing clot formation extends beyond controlling platelet function. In this study, we evaluate NO's effect on factor XII (fibrinogen) adsorption and activation, which causes the initiation of the intrinsic arm of the coagulation cascade. This is done by utilizing a model plasticized poly(vinyl) chloride (PVC), N-diazeniumdiolate system and looking at the adsorption of fibrinogen, an important clotting protein, to these surfaces. The materials have been prepared in such a way to eliminate changes in surface properties between the control (plasticized PVC) and composite (NO-releasing) materials. This allows us to isolate NO release and determine the effect on the adsorption of fibrinogen, to the material surface. Surprisingly, it was found that an NO releasing material with a surface flux of 17.4 ± 0.5 × 10(-10) mol NO cm(-2) min(-1) showed a significant increase in the amount of fibrinogen adsorbed to the material surface compared to one with a flux of 13.0 ± 1.6 × 10(-10) mol NO cm(-2) min(-1) and the control (2334 ± 496, 226 ± 99, and 103 ±31% fibrinogen adsorbed of control, respectively). This study suggests that NO's role in controlling clotting is extended beyond platelet activation. © 2013 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 101A: 3201-3210, 2013. PMID:23554300

Lantvit, Sarah M; Barrett, Brittany J; Reynolds, Melissa M

2013-04-02

185

Use of brown coal coke as an adsorbent (Report on ECSC contract 7220-EC/114)  

Energy Technology Data Exchange (ETDEWEB)

Investigations which have been carried out on the use of brown coal as an adsorbent are reported. Brown coal coke produced in an industrial-scale rotary furnace was used as an adsorbent to treat industrial water, waste water and waste gases. The degree of purification reached depends on the composition of waste water, grain size of the coke and design of the adsorption plant.

1983-01-01

186

Thiophilic adsorbents for RIA and ELISA procedures.  

UK PubMed Central (United Kingdom)

Three types of agarose derivatives have been prepared and investigated as adsorbents for radioimmunoassay and ELISA analysis. The analytical systems were evaluated using beta 2 microglobulin as a model. After a competitive reaction between the immunocomponents in solution, the formed immune complexes were adsorbed onto the adsorbent in the presence of 0.5 M potassium sulfate in 0.1 M Tris, pH 7.5. The binding constant between the interaction site on human IgG and the adsorbent 3-(2-pyridylthio)-2-hydroxypropylagarose (Py-S-gel) was determined to be 1.5 x 10(7) M-1 and the binding capacity was 20 mg/ml gel. The immune complex was desorbed by deleting potassium sulfate from the buffer, and only 0.5% of the total applied protein remained after washing the adsorbent with 0.5 M NaOH. The same adsorbent can be used repetitively with different systems.

Oscarsson S; Chaga G; Porath J

1991-10-01

187

A novel fiber-based adsorbent technology  

Energy Technology Data Exchange (ETDEWEB)

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

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

1997-10-01

188

Compositionality  

UK PubMed Central (United Kingdom)

The first topic of the paper is to provide a formalization of the principle ofcompositionality of meaning. A mathematical model (based upon universalalgebra) is presented, and its properties are investigated. The second topic isto discuss arguments from the literature against compositionality (of Hintikka,Higginbotham, Pelletier, Partee, Schi#er and others). Methods are presentedthat help to obtain compositionality. It is argued that the principle is shouldnot be considered an empirical verifyable restriction, but a methodologicalprinciple that describes how a system for syntax and semantics should bedesigned. The paper has an appendix by B. Partee on the compositionaltreatment of genitives.# To appear in J.F.A.K. van Benthem & A. ter Meulen (eds.), Handbook of Logic and Linguistics,Elsevier Science Publishers, Amsterdam1 The principle of compositionality of meaning1.1 The principleThe principle of compositionality reads, in its best known formulation:The m...

Theo M. V. Janssen

189

Compositionality  

UK PubMed Central (United Kingdom)

The first topic of the paper is to provide a formalization of the principle ofcompositionality of meaning. A mathematical model (based upon universalalgebra) is presented, and its properties are investigated. The second topic isto discuss arguments from the literature against compositionality (of Hintikka,Higginbotham, Pelletier, Partee, Schi#er and others). Methods are presentedthat help to obtain compositionality. It is argued that the principle is shouldnot be considered an empirical verifyable restriction, but a methodologicalprinciple that describes how a system for syntax and semantics should bedesigned. The paper has an appendix by B. Partee on the compositionaltreatment of genitives.# To appear in J.F.A.K. van Benthem & A. ter Meulen (eds.), Handbook of Logic and Linguistics,Elsevier Science Publishers, Amsterdam1 The principle of compositionality of meaning1.1 The principleThe principle of compositionality reads, in its best known formulation:The meaning o...

Theo M. V. Janssen

190

Compositions  

UK PubMed Central (United Kingdom)

An ingestible particulate composition comprises: a) at least one compound selected from the group consisting of 2,4-dichlorobenzyl alcohol, amylmetacresol, cetylpyridinium chloride, hexitidine, hexylresorcinol, flurbiprofen, lidocaine, benzocaine, ibuprofen, paracetamol, pectin, menthol, and benzydamine and b) one or more bioadhesive materials. Resulting particulate compositions have excellent flow characteristics, dust suppression, organoleptic properties and stability. They are highly suitable for administration direction into a patient's mouth, and ingested to alleviate the symptoms of a sore throat.

CAMPBELL ALISTAIR

191

Hierarchically Structured Manganese Oxide-Coated Magnetic Nanocomposites for Efficient Removal of Heavy Metal Ions from Aqueous Systems.  

UK PubMed Central (United Kingdom)

In this study, hierarchical MnO2-coated magnetic nanocomposite (Fe3O4/MnO2) was synthesized by a mild hydrothermal process, and then its application for removing heavy metal ions from contaminated water systems was examined. Structural characterization showed that Fe3O4 nanoparticle core was coated with amorphous MnO2 shell with flowerlike morphology. The as-prepared nanocomposite had a large surface area and high magnetic saturation value, which ensure the good sorption ability and convenience of separation. The Fe3O4/MnO2 exhibited a greatly improved removal capacity toward four different heavy metals (Cd(II), Cu(II), Pb(II), Zn(II)) compared to unmodified Fe3O4 nanoparticles. The adsorption property of Fe3O4/MnO2 was studied with Cd(II) in more detail. The sorption equilibrium data were well fitted to the Langmuir model, and the maximum adsorption capacity toward Cd(II) was 53.2 mg•g-1. The Fe3O4/MnO2 retained over 80% of adsorption capacity under various solution conditions that are typically encountered in natural waters. This nanocomposite was easily recovered and reused through consecutive adsorption-desorption experiments with the assistance of external magnetic field. Overall findings propose that Fe3O4/MnO2 could be used as an effective recyclable adsorbent for heavy metal ions.

Kim EJ; Lee CS; Chang YY; Chang YS

2013-09-01

192

Adsorbent storage for natural gas vehicles  

Energy Technology Data Exchange (ETDEWEB)

This review with 75 references traces the background to natural gas vehicles, and examines the storage of natural gas, adsorbents, adsorbent fill-empty testing, and the use of a pre-adsorption system to remove heavier hydrocarbon from the natural gas which has a greater adsorption potential than methane prior to adsorption in the main storage tank. A diagram of a basic layout for a vehicular adsorbed natural gas storage system is provided, details of some studies of methane storage using Amoco type potassium hydroxide activated carbon adsorbents are tabulated. (UK)

Cook, T.L. [Atlanta Gas Light Co., GA (United States); Komodromos, C. [British Gas plc, Loughborough (United Kingdom); Quinn, D.F. [Royal Military College of Canada, Kingston, ONT (Canada); Ragan, S. [Sutcliffe Speakman Carbons Ltd., Ashton-in-Makersfield (United Kingdom)

1999-07-01

193

Bunched and dispersed carbon fiber adsorbents for dextoxication.  

UK PubMed Central (United Kingdom)

"Actilen" and "Vaulen" carbon fiber adsorbents in bunched, stapled and dispersed form for haemosorption, topical application and enterosorption have been developed. The sorbents possess homogeneously porous structure and chemically active surface which may be controlled in the process of material synthesis. Fiberous sorbents have stood toxicological trials and are now approved for clinical application. "Vaulen" enterosorbent developed by Leningrad Institute of Man-made Fibers and Composite Materials, Institute of General and Inorganic Chemistry of White Russian Academy of Sciences, Military Medical Academy and White Russian Scientific Research Sanitary Institute is recommended by the Pharmacological Committee of Soviet Ministry of Public Health to be ready for clinical application. Actilen carbon fiber adsorbent for haemosorption and topical application therapy was awarded a gold medal at the 1984 Leipzig Fair.

Fridman LI

1989-01-01

194

[Direction of amino acid adsorbed by surface film on titanium  

UK PubMed Central (United Kingdom)

The purpose of the study was to investigate the influence of the isoelectric point and residue of an amino acid on the adsorption of the amino acid by titanium in order to elucidate the adsorption of proteins by titanium. The direction of amino acid adsorbed by a titanium surface in an electrolytic solution was determined using X-ray photoelectron spectroscopy (XPS) and Fourier transform infrared reflection absorption spectroscopy (FT-IR-RAS). Apparently, the influence of amino acid on the composition and thickness of surface films on titanium is minimal if the film is formed in an electrolytic solution. The pH of the electrolytic solution and the residue of amino acids are responsible for the direction of the amino acid adsorbed by surface film formed on titanium in solution.

Hanawa T

1989-11-01

195

Adsorbed gas in coal seam  

Energy Technology Data Exchange (ETDEWEB)

Method of measurement and prospecting of the adsorbed gas in the coal seam are not yet integrated. In this experiment, two methods of measuring the gas desorption of the bored coal powder were used; one is the conventional method and another is a newly developed method. From the measurement and the calculation, it was found that Aiery's equation gave the highest amount of the lost gas, then the root t method, then finally the Darcy method. From the viewpoint of safety, Aiery's method seems best at the present time. In this measurement, the maximum gas occlusion was 14.49 m/sup 3/ per ton of coal. Measurement by means of gas desorption meter is quite effective for the man-power saving in instrumentation and analysis. (3 figs, 2 tabs, 6 refs)

Oga, Kotaro; Higuchi, Kiyoshi; Koizumi, Koichi

1988-04-01

196

Radiolysis of substances adsorbed on oxides surface  

International Nuclear Information System (INIS)

Experimental results of investigation into radiolysis of water molecules and nitrate anions on the surface of oxides powders are given. Effect of oxide nature, degree of its dispersity and presence of impurities on efficiency of adsorbate radiolysis is considered. Regularities of adsorbed substance radiolysis and possible mechanisms of processes are discussed.

1991-01-01

197

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

Science.gov (United States)

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

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

2010-12-01

198

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

UK PubMed Central (United Kingdom)

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

Hu B; Fugetsu B; Yu H; Abe Y

2012-05-01

199

Composition  

UK PubMed Central (United Kingdom)

A composition comprising dried microorganisms, obtainable by a process comprising: culturing one or more species of a microorganism admixing the cultured microorganism with one or more zeolite carriers such that the culture to carrier ratio is less than 1:4 (w/w) treating the microorganism with pulsed electromagnetic fields incubating the culture: carrier mixture for at least 6 hours and drying the microorganism so as to reduce the moisture level to between 1 wt % to 6 wt %. The combination of admixing the cultured microorganism with one or more carriers and treating the microorganism with pulsed electromagnetic fields results in the dried microorganisms in the composition have significantly enhanced initial survival rate and/or shelf-life.

PEDERSEN HANS CHRISTIAN; WEIERGANG INGE

200

Compositeness  

International Nuclear Information System (INIS)

My lectures will be devoted to an introductory discussion of compositeness for the Higgses, the W and Z and the quarks and leptons. This list does not contain massless vector bosons, like the gluons, associated to a local gauge symmetry. A theorem states that a theory with a Lorentz-covariant conserved current cannot have massless particles of spin greater than 1/2 with a nonvanishing value of the associated charge. This implies that massless spin-one particles can exist only if they are explicitly associated to a locally gauge-invariant symmetry (in this case, the current J? is not Lorentz-covariant). In other words, if one wants gauge invariance, one has to buy it from the beginning. There is no point in seeking for composite gluons when, in order to obtain them, one must have local colour symmetry already realized (and, therefore, gluons already there). (orig./BBO).

1984-07-06

 
 
 
 
201

COMPOSITION  

UK PubMed Central (United Kingdom)

A hair conditioning composition comprising an oil blend, said blend comprising: (i)from 10% to 95%, by weight based on total weight, of a first oily component which is selected from coconut oil, sunflower oil, almond oil and mixtures thereof, and (ii)from 5% to 90%, by weight based on total weight, of a second oily component which is one or more hydrocarbon oils of average carbon chain length less than 20 carbon atoms.

IVANOVA KATYA

202

Inorganic chemically active adsorbents (ICAAs)  

Energy Technology Data Exchange (ETDEWEB)

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

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

1997-10-01

203

Site blocking effects on adsorbed polyacrylamide conformation  

Science.gov (United States)

The use of polymers as flocculating additives is a common practice in many manufacturing environments. However, exactly how these polymers interact with surfaces is relatively unknown. One specific topic which is thought to be very important to flocculation is an adsorbed polymer's conformation. Substantial amounts of previous work, mainly using simulations, have been performed to elucidate the theory surrounding adsorbed polymer conformations. Yet, there is little experimental work which directly verifies current theory. In order to optimize the use of polymer flocculants in industrial applications, a better understanding of an adsorbed polymer's conformation on a surface beyond theoretical simulations is necessary. This work looks specifically at site blocking, which has a broad impact on flocculation, adsorption, and surface modification, and investigated its effects on the resulting adsorbed polymer conformation. Experimental methods which would allow direct determination of adsorbed polymer conformational details and be comparable with previous experimental results were first determined or developed. Characterization of an adsorbed polymer's conformation was then evaluated using dynamic light scattering, a currently accepted experimental technique to examine this. This commonly used technique was performed to allow the comparison of this works results with past literature. Next, a new technique using atomic force microscopy was developed, building on previous experimental techniques, to allow the direct determination of an adsorbed polymer's loop lengths. This method also was able to quantify changes in the length of adsorbed polymer tails. Finally, mesoscopic simulation was attempted using dissipative particle dynamics. In order to determine more information about an adsorbed polymer's conformation, three different environmental factors were analyzed: an adsorbed polymer on a surface in water, an adsorbed polymer on a surface in aqueous solutions of varying ionic strength, and an adsorbed polymer on a surface functionalized with site blocking additives. This work investigated these scenarios using a low charge density high molecular weight cationic polyacrylamide. Three different substrates, for polymer adsorption were analyzed: mica, anionic latex, and glass. It was determined that, similar to previous studies, the adsorbed polymer layer thickness in water is relatively small even for high molecular weight polymers, on the order of tens of nanometers. The loop length distribution of a single polymer, experimentally verified for the first time, revealed a broad span of loop lengths as high as 1.5 microns. However, the bulk of the distribution was found between 40 and 260 nanometers. For the first time, previous theoretical predictions regarding the salt effect on adsorbed polymer conformation were confirmed experimentally. It was determined that the adsorbed polymer layer thickness expanded with increasing ionic strength of the solvent. Using atomic force microscopy, it was determined that the adsorbed polymer loop lengths and tail lengths increased with increasing ionic strength, supporting the results found using dynamic light scattering. The effect of the addition of site blocking additives on a single polymer's conformation was investigated for the first time. It was determined that the addition of site blocking additives caused strikingly similar results as the addition of salt to the medium. The changes in adsorbed polymer's loop lengths was found to be inconsistent and minimal. However, the changes in an adsorbed polymer's free tail length was found to increase with increasing site blocking additive levels. These results were obtained using either PDADMAC or cationic nanosilica as site blocking additives.

Brotherson, Brett A.

204

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

Directory of Open Access Journals (Sweden)

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

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

2011-01-01

205

COMPOSITION.  

UK PubMed Central (United Kingdom)

The present invention provides a composition comprising (a) an antimicrobial compound of the formula (I) wherein R1 is a fatty acid chain R2 is a linear or branched alkyl residue having from 1 to 12 carbon atoms n is an integer from 0 to 10 X- is selected from Br-, I-, Cl- and HSO4 (b) an antimicrobial material selected from lanthionine bacteriocins, tea [Camellia sinensis] extract, hop [Humulus lupulus L.] extract, grape skin extract, grape seed extract, Uva Ursi extract and combinations thereof.

MYGIND TINA; SIGMUNDSSON ARNAR; FISCHER JANA

206

Composition  

UK PubMed Central (United Kingdom)

The present invention provides a composition comprising (a) an antimicrobial compound of the formula (I) wherein R1 is a fatty acid chain R2 is a linear or branched alkyl residue having from 1 to 12 carbon atoms n is an integer from 0 to 10 X- is selected from Br-, I-, Cl- and HSO4 (b) an antimicrobial material selected from lanthionine bacteriocins, tea [Camellia sinensis] extract, hop [Humulus lupulus L.] extract, grape skin extract, grape seed extract, Uva Ursi extract and combinations thereof.

MYGIND TINA; SIGMUNDSSON ARNAR; FISCHER JANA

207

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

International Nuclear Information System (INIS)

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

2009-04-15

208

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

Directory of Open Access Journals (Sweden)

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

A. Dudek; J. Iwaszko

2008-01-01

209

Regenerable activated bauxite adsorbent alkali monitor probe.  

Science.gov (United States)

This invention relates to a regenerable activated bauxite adsorber alkali monitor probe for field applications to provide reliable measurement of alkali-vapor 5 concentration in combustion gas with special emphasis on pressurized fluidized-bed combustion ...

S. H. D. Lee

1991-01-01

210

Spherical Adsorbers and Catalysts from Aluminium Oxides  

International Science & Technology Center (ISTC)

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

211

New liquid waste control with tannin adsorbent  

International Nuclear Information System (INIS)

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

1998-01-01

212

New liquid waste control with tannin adsorbent  

Energy Technology Data Exchange (ETDEWEB)

Since 1971, the Mitsubishi Nuclear Fuel Co., Ltd. (MNF) has been fabricating PWR fuels and developing related technology and processes. In the UF{sub 6} reconversion lines of MNF, the ammonium diuranate (ADU) process has been operating and the newly developed process of liquid waste treatment was installed last year. The characteristic of this process is to use insoluble tannin adsorbent which has been developed by MNF. The tannin adsorbent is not only an effective means to adsorb heavy metals such as uranium and plutonium but is also easy to incinerate at low temperature. Control of radioactive liquid waste from nuclear facilities is generally implemented by co-precipitation. However, it produces secondary wastes such as noncombustible materials which include radionuclides and it is anticipated that the storage and disposal of those wastes will be at high cost. Those are the reasons why tannin adsorbent has an advantage, and why MNF develops it. (author)

Nakamura, Yoshinobu; Shirato, Wataru; Nakamura, Yasuo [Mitsubishi Nuclear Fuel Co., Ltd. (Japan)

1998-07-01

213

IR investigations of surfaces and adsorbates  

Energy Technology Data Exchange (ETDEWEB)

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

Gwyn Williams

2001-12-10

214

Regenerable activated bauxite adsorbent alkali monitor probe  

Energy Technology Data Exchange (ETDEWEB)

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

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

1992-01-01

215

Regenerable activated bauxite adsorbent alkali monitor probe  

Energy Technology Data Exchange (ETDEWEB)

A regenerable activated bauxite adsorber alkali monitor probe for field applications to provide reliable measurement of alkali-vapor concentration in combustion gas with special emphasis on pressurized fluidized-bed combustion (PFBC) off-gas. More particularly, the invention relates to the development of a easily regenerable bauxite adsorbent for use in a method to accurately determine the alkali-vapor content of PFBC exhaust gases. 6 figs.

Lee, S.H.D.

1992-12-22

216

Regenerable activated bauxite adsorbent alkali monitor probe  

Energy Technology Data Exchange (ETDEWEB)

This invention relates to a regenerable activated bauxite adsorber alkali monitor probe for field applications to provide reliable measurement of alkali-vapor 5 concentration in combustion gas with special emphasis on pressurized fluidized-bed combustion (PFBC) off-gas. More particularly, the invention relates to the development of a easily regenerable bauxite adsorbent for use in a method to accurately determine the alkali-vapor content of PFBC 10 exhaust gases.

Lee, S.H.D.

1991-01-22

217

Zircaloy Oxidation in Air: Effects of Adsorbates  

Energy Technology Data Exchange (ETDEWEB)

The air oxidation of Zry and the effects of adsorbates on the oxidation are found by the intermittent measurements of the weight gain of specimens. LiOH and NaCl are the adsorbates tested in this paper. NaCl enhances the oxidation, where nonuniform stresses on the surface and Cl ions are the cause of the enhancement. LiOH also enhances the oxidation, where initial porous oxide seem to the reason.

Cho, Yoon Chol; Park, Kwang Heon [Kyunghee Univ., Suwon (Slovakia)

1995-09-15

218

Oil adsorbent and process for preparation thereof  

Energy Technology Data Exchange (ETDEWEB)

An effective and regenerable oil adsorbent is obtained from a pitch-like substance formed by heat-treating a heavy hydrocarbon oil to such an extent that the volatile matter content thereof is about 10% by weight to about 60% by weight, preferably about 30 to about 50% by weight. By using this oil adsorbent, oil-removing purification treatment of oil-contaminated water can be effectively achieved with economical advantages.

Hayashi, M.; Noguchi, K.; Tanaka, H.; Yoshimura, K.

1980-06-24

219

NMR study of nanophase Al/Al-oxide powder and consolidated composites  

Energy Technology Data Exchange (ETDEWEB)

{sup 27}Al Nuclear Magnetic Resonance (NMR) measurements from aluminum powders and consolidated nanophase aluminum made from those powders are presented. The signals from the metal and surface oxidation are easily separated and are compared before and after consolidation. The results presented indicate that the oxide coating becomes the interface region within the nanophase composite material and that during consolidation the metal has undergone a deformation equivalent to that seen for bulk material under a compressive strain of between 4% and 8%.

Suits, B.H.; Apte, P.; Wilken, D.E. [Michigan Technological Univ., Houghton, MI (United States). Dept. of Physics; Siegel, R.W. [Argonne National Lab., IL (United States). Materials Science Div.

1994-10-01

220

Supported Ag nanoparticles as trace iodide adsorbent from acetic acid  

Science.gov (United States)

Ag nanoparticles (AgNPs) were used as adsorbent to remove trace iodide from acetic acid. Under identical conditions, AgNPs adsorbent with 0.5 wt % Ag has the same performance as commercial adsorbent with 10 wt % Ag+. In addition, Ag loss of AgNPs adsorbent is remarkably lower than that of commercial adsorbent. The Ag content in AgNPs adsorbent affects its adsorption performance, and the optimal content is 1.0 wt %. Saturated AgNPs adsorbent can be regenerated by hydrogen reduction and reused with satisfying performance. The properties of AgNPs adsorbent are based on surface effect of nanoparticles, differing from commercial Ag+ type adsorbents. In a word, AgNPs adsorbent is of high efficiency, low Ag loss and easy recycling, thus making it "green adsorbent" for removing iodide from acetic acid.

Qian, Qingli; Shao, Shouyan; Yan, Fang; Ling, Chen; Yan, Fengwen; Cao, Hongbing; Guo, Cun-Yue; Yuan, Guoqing

2012-09-01

 
 
 
 
221

Thiophilic adsorbents for RIA and ELISA procedures.  

Science.gov (United States)

Three types of agarose derivatives have been prepared and investigated as adsorbents for radioimmunoassay and ELISA analysis. The analytical systems were evaluated using beta 2 microglobulin as a model. After a competitive reaction between the immunocomponents in solution, the formed immune complexes were adsorbed onto the adsorbent in the presence of 0.5 M potassium sulfate in 0.1 M Tris, pH 7.5. The binding constant between the interaction site on human IgG and the adsorbent 3-(2-pyridylthio)-2-hydroxypropylagarose (Py-S-gel) was determined to be 1.5 x 10(7) M-1 and the binding capacity was 20 mg/ml gel. The immune complex was desorbed by deleting potassium sulfate from the buffer, and only 0.5% of the total applied protein remained after washing the adsorbent with 0.5 M NaOH. The same adsorbent can be used repetitively with different systems. PMID:1940385

Oscarsson, S; Chaga, G; Porath, J

1991-10-25

222

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

Science.gov (United States)

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

Zhu, Xianyong; Liu, Jiaan

2013-10-01

223

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

Directory of Open Access Journals (Sweden)

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

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

2013-01-01

224

[Biocompatibility of silicon containing micro-arc oxidation coated magnesium alloy ZK60 with osteoblasts cultured in vitro].  

UK PubMed Central (United Kingdom)

OBJECTIVE: To research in vitro biocompatibility of silicon containing micro-arc oxidation (MAO) coated magnesium alloy ZK60 with osteoblasts. METHODS: The surface microstructure of silicon containing MAO coated magnesium alloy ZK60 was observed by a scanning electron microscopy (SEM), and chemical composition of the coating surface was determined by energy dispersive spectrum analysis. The experiments were divided into 4 groups: silicon containing MAO coated magnesium alloy ZK60 group (group A), uncoated magnesium alloy ZK60 group (group B), titanium alloy group (group C), and negative control group (group D). Extracts were prepared respectively with the surface area to extraction medium ratio (1.25 cm(2)/mL) according to ISO 10993-12 standard in groups A, B, and C, and were used to culture osteoblasts MC3T3-E1. The a-MEM medium supplemented with 10% fetal bovine serum was used as negative control in group D. The cell morphology was observed by inverted phase contrast microscopy. MTT assay was used to determine the cell viability. The activity of alkaline phosphatase (ALP) was detected. Cell attachment morphology on the surface of different samples was observed by SEM. The capability of protein adsorption of the coating surface was assayed, then DAPI and calcein-AM/ethidium homodimer 1 (calcein-AM/EthD-1) staining were carried out to observe cell adhesion and growth status. RESULTS: The surface characterization showed a rough and porous layer with major composition of Mg, O, and Si on the surface of silicon containing MAO coated magnesium alloy ZK60 by SEM. After cultured with the extract, cells grew well and presented good shape in all groups by inverted phase contrast microscopy, group A was even better than the other groups. At 5 days, MTT assay showed that group A presented a higher cell proliferation than the other groups (P < 0.05). Osteoblasts in groups A and C presented a better cell extension than group B under SEM, and group A exhibited better cell adhesion and affinity. Protein adsorption in group A [ (152.7 +/- 6.3) microg/mL] was significantly higher than that of group B [(96.3 +/-3.9) microg/mL] and group C [ (96.1 +/-8.7) microg/mL] (P < 0.05). At each time point, the adherent cells on the sample surface of group A were significantly more than those of groups B and C (P < 0.05). The calcein-AM/EthD-1 staining showed that groups A and C presented better cell adhesion and growth status than group B. The ALP activities in groups A and B were 15.55 +/-0.29 and 13.75 +/-0.44 respectively, which were significantly higher than those in group C (10.43 +/-0.79) and group D (10.73 +/-0.47) (P < 0.05), and group A was significantly higher than group B (P < 0.05). CONCLUSION: The silicon containing MAO coated magnesium alloy ZK60 has obvious promoting effects on the proliferation, adhesion, and differentiation of osteoblasts, showing a good biocompatibility, so it might be an ideal surface modification method on magnesium alloys.

Yang X; Yin Q; Zhang Y; Li M; Lan G; Lin X; Tan L; Yang K

2013-05-01

225

Comparison of the protein adsorption selectivity of salt-promoted agarose-based adsorbents. Hydrophobic, thiophilic and electron donor-acceptor adsorbents.  

UK PubMed Central (United Kingdom)

Protein adsorption of human serum onto six different agarose-based chromatographic gels that were representative of the salt-promoted adsorbent family [octyl- and phenyl-Sepharose, mercaptoethanol-divinyl sulfone agarose (T gel), mercaptomethylene pyridine-derivatized agarose gel (MP gel), tricyanoaminopropene-divinyl sulfone agarose (DVS-TCP gel), tricyanoamino-propene-bisoxirane agarose (bisoxirane-TCP gel)] was studied in the presence of moderate or high concentrations of the water structuring salt, sodium sulfate. Study of the protein adsorption selectivity by two-dimensional gel electrophoresis revealed an opposed selectivity for hydrophobic interaction adsorbents and electron donor-acceptor adsorbents. The T gel, MP gel and TCP gels belonged to the electron donor-acceptor adsorbents, displaying a main selectivity for immunoglobulins, whereas octyl-Sepharose belonged to the hydrophobic adsorbents, displaying a main selectivity for 'hydrophobic' proteins. Phenyl-Sepharose for its part was described as an example of a composite selectivity of both families. The conclusion of this work is two-fold: (1) hydrophobic interaction chromatography (HIC) and electron donor-acceptor chromatography (EDAC) have opposed protein selectivities and are both salt-promoted. As a main consequence, it means that high concentrations of a water-structuring salt can promote different types of weak molecular interactions, resulting in different protein adsorption selectivities: (2) thiophilic adsorption chromatography (TAC) should be renamed EDAC as similar protein selectivity is demonstrated for electron donor-acceptor ligand devoid of sulfur atoms.

Berna PP; Berna N; Porath J; Oscarsson S

1998-03-01

226

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

International Nuclear Information System (INIS)

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

1988-01-01

227

Relationship of reaction rate to amounts adsorbed for the low-temperature ortho-para hydrogen shift  

Energy Technology Data Exchange (ETDEWEB)

The relationships between the amounts of adsorbed reactant and product and the forward and reverse reaction rates were measured for the ortho-para hydrogen system on a chromia-alumina catalyst at 75.7 K. Total adsorption was measured rapidly; individual species isotherms as functions of pressure and composition were extracted from the total adsorption data. Reaction rates were determined as functions of pressure and composition using an integral, packed-bed reactor. The resulting relationship s between individual surface reaction rates and the amounts of adsorbed reactants are nonlinear. The observed results can be explained by a reaction mecha nism involving mobile adsorbed products and reactants. The reactants in this system primarily are physically adsorbed, so these results may be generalized to other systems only with caution.

Kauffman, D.; Brown, L.F.; Manogue, W.H.

1981-10-01

228

Removal of cyanide by eggshell as low-cost adsorbent  

Directory of Open Access Journals (Sweden)

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

Ghorban Asgari; AbdolMotaleb Seid Mohammadi; Amir Shabanlo; Jamal Mehr Ali Pour

2013-01-01

229

Novel Fiber-Based Adsorbent Technology  

Energy Technology Data Exchange (ETDEWEB)

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.

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

2001-08-31

230

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

UK PubMed Central (United Kingdom)

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

Yang J; Strickler JR; Gunasekaran S

2012-08-01

231

Protein purification using magnetic adsorbent particles  

DEFF Research Database (Denmark)

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

Franzreb, M; Siemann-Herzberg, M.

2006-01-01

232

METHOD FOR PRODUCING CARBON DIOXIDE CHEMICAL ADSORBENT  

UK PubMed Central (United Kingdom)

The invention relates to methods for producing carbon dioxide chemical adsorbent which is based on hydroxides of alkali and/ or alkali-earth metals and can be used in means for protecting respiratory organs. The method for producing carbon dioxide chemical adsorbent for respiratory systems involves combining alkali and/ or alkali-earth metal hydroxides with a fibrous material, shaping adsorbent in the form of a sheet and drying it. The alkali and/or alkali-earth metal hydroxides are used in the form of an aqueous dispersion and the alkali and/ or alkali-earth metal hydroxides is combined with the fibrous material by accommodating the aqueous dispersion between the layers of a porous fibrous material. The alkali and/or alkali-earth metal hydroxides such as potassium hydroxide, sodium hydroxide, lithium hydroxide, calcium hydroxide, magnesium hydroxide and the similar hydroxides chemically active to carbon dioxide can be used as metal hydroxides. The aqueous dispersion can be of a paste or suspension consistency or in the form of a solution. The following materials can be used as a porous fibrous material: fibre paper, glass-fiber mat, heat resistant non-flammable materials such as Nomex, Kevlar (Du Pont, USA), Rusar and Arselon (Russia) and any other alkali-proof low specific density materials. The invention makes it possible to increase by 20-40% the reaction capacity of the adsorbent, thereby extending the possibilities of using it in systems for removing carbon dioxide from air, the adsorbent production method being technologically simple.

GLADYSHEV NIKOLAI FEDOROVICH; GLADYSHEVA TAMARA VIKTOROVNA; KOZADAEV LEONID EDUARDOVICH; SIMANENKOV EDUARD ILIICH; PUTIN BORIS VIKTOROVICH; PUTIN SERGEI BORISOVICH; ARKHIPOVA MARINA PETROVNA; TYANIKOV ANATOLY VASILIEVICH

233

Local models for the interaction of adsorbates with surfaces  

Science.gov (United States)

Local models on the basis of the surface cluster approach have been applied extensively in the study of surface and adsorbate systems. The energetic details of the adsorbate-substrate interaction can be characterized in these models by the constrained space orbital variation (CSOV) method. This method allows a detailed study of adsorbate binding in different surface sites. Further, consequences of the chemisorptive interaction for adsorbate valence photoemission and vibrational properties of adsorbed molecules can be studied.

Hermann, K.; Bagus, P. S.

1987-09-01

234

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

Science.gov (United States)

Experimental results are presented for the verification of the specific interaction step of the ‘adsorbed template’ biogeochemical cycle, a simple model for a primitive prebiotic replication system. The experimental system consisted of gypsum as the mineral to which an oligonucleotide template attaches (Poly-C or Poly-U) and 5'-AMP, 5'-GMP, 5'-CMP and 5'-UMP as the interacting biomonomers. When Poly-C or Poly-U were used as adsorbed templates, 5'-GMP and 5'-AMP, respectively were observed to be the most strongly adsorbed species. Moreover, there exists a direct quantitative relationship between the quantity of cytidine or uracil residues in the adsorbed state and the amount of the complementary mononucleotide that is attached to it. NaCl added to the system in order to create conditions of high ionic strength seems to enhance the selectivity of the adsorption of the monmucleotides to these adsorbed templates.

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

1988-12-01

235

Leed study of small molecules adsorbed on thin epitaxial iron oxide layers  

Energy Technology Data Exchange (ETDEWEB)

1 monolayer FeO and 8 monolayers Fe3O4 films were formed by UHV deposition of iron on a Pt(111) single crystal followed by oxidation at 800 K. The composition of the films was determined by AES and their structure by LEED. Intensity-Voltage curves were recorded. CO, H2O, Methanol, ethylene and benzene were then adsorbed on the oxide films at temperatures between 130 K and 300 K. The adsorbed layers were characterized by AES, TPD and LEED.

Reniers, F.; Van Hove, M.; Somorjai, G. [Lawrence Berkeley National Lab., CA (United States)

1997-12-31

236

Separation of ash from regenerated adsorbent  

Energy Technology Data Exchange (ETDEWEB)

A process for separating ash particles from an aqueous slurry containing a mixture of regenerated adsorbent (e.g. carbon) and ash particles includes the steps of settling the slurry to produce a solid phase including the mixture of adsorbent and ash particles and supernatant or clarified aqueous phase. After separation of the aqueous phase, a slurry of the solid phase is diluted with water and a dispersing agent for promoting suspension of the ash particles and an anionic polymer for promoting settling of the adsorbent particles are added to the dilute solid phase slurry. The thus treated, dilute slurry is settled to produce an aqueous phase containing primarily suspended ash particles and a solid phase including carbon particles. After separation, the solid phase can be returned to a wastewater treatment system.

Hoffman, M.C.; Dietrich, M.J.; Oettinger, T.P.

1988-08-10

237

Standoff spectroscopy of surface adsorbed chemicals.  

UK PubMed Central (United Kingdom)

Despite its immediate applications, selective detection of trace quantities of surface adsorbed chemicals, such as explosives, without physically collecting the sample molecules is a challenging task. Standoff spectroscopic techniques offer an ideal method of detecting chemicals without using a sample collection step. Though standoff spectroscopic techniques are capable of providing high selectivity, their demonstrated sensitivities are poor. Here we describe standoff detection of trace quantities of surface adsorbed chemicals using two quantum cascade lasers operated simultaneously, with tunable wavelength windows that match with absorption peaks of the analytes. This standoff method is a variation of photoacoustic spectroscopy, where scattered light from the sample surface is used for exciting acoustic resonance of the detector. We demonstrate a sensitivity of 100 ng/cm(2) and a standoff detection distance of 20 m for surface adsorbed analytes such as explosives and tributyl phosphate.

Van Neste CW; Senesac LR; Thundat T

2009-03-01

238

Adsorbate transport on graphene by electromigration.  

UK PubMed Central (United Kingdom)

Chemical functionalization of graphene holds promise for various applications ranging from nanoelectronics to catalysis, drug delivery, and nanoassembly. In many applications it is important to be able to transport adsorbates on graphene in real time. We propose to use electromigration to drive the adsorbate transport across the graphene sheet. To assess the efficiency of electromigration, we develop a tight-binding model of electromigration of an adsorbate on graphene and obtain simple analytical expressions for different contributions to the electromigration force. Using experimentally accessible parameters of realistic graphene-based devices as well as electronic structure theory calculations to parametrize the developed model, we argue that electromigration on graphene can be efficient. As an example, we show that the drift velocity of atomic oxygen covalently bound to graphene can reach ~1 cm/s.

Solenov D; Velizhanin KA

2012-08-01

239

Adsorbate Transport on Graphene by Electromigration  

Science.gov (United States)

Chemical functionalization of graphene holds promise for various applications ranging from nanoelectronics to catalysis, drug delivery, and nanoassembly. In many applications it is important to be able to transport adsorbates on graphene in real time. We propose to use electromigration to drive the adsorbate transport across the graphene sheet. To assess the efficiency of electromigration, we develop a tight-binding model of electromigration of an adsorbate on graphene and obtain simple analytical expressions for different contributions to the electromigration force. Using experimentally accessible parameters of realistic graphene-based devices as well as electronic structure theory calculations to parametrize the developed model, we argue that electromigration on graphene can be efficient. As an example, we show that the drift velocity of atomic oxygen covalently bound to graphene can reach ˜1cm/s.

Solenov, Dmitry; Velizhanin, Kirill A.

2012-08-01

240

Enhanced adsorption of fluoride from aqueous solution using an iron-modified attapulgite adsorbent.  

UK PubMed Central (United Kingdom)

Attapulgite modified with iron was used as an adsorbent for fluoride removal from aqueous solutions. The pristine attapulgite and the iron-modified attapulgite composite were characterized by X-ray powder diffraction (XRD), Fourier transform infrared (FT-IR) techniques, and the pH point of zero charge measurement. The XRD analysis indicates the existence of iron oxide hydroxide (FeO[OH]) in the iron-modified attapulgite composite. The FT-IR spectra of the iron-modified attapulgite composite before and after adsorption indicate that the involvement of the hydroxide radical in the fluoride adsorption. The effects of pH, contact time, initial concentration, and temperature on fluoride adsorption by the adsorbent were studied in a batch system. Kinetics studies show that the fluoride adsorption kinetics over the adsorbent is well-described by the pseudo-second-order kinetic model. The fluoride adsorption isotherm is well-fitted by the Langmuir model. Desorption studies show that the iron-modified attapulgite adsorbent can be easily regenerated at pH 12.5. The adsorption mechanism is discussed in detail.

He ZL; Zhang GK; Xu W

2013-02-01

 
 
 
 
241

Indirect interactions of membrane-adsorbed cylinders  

CERN Multimedia

Biological and biomimetic membranes often contain aggregates of embedded or adsorbed macromolecules. In this article, the indirect interactions of cylindrical objects adhering to a planar membrane are considered theoretically. The adhesion of the cylinders causes a local perturbation of the equilibrium membrane shape, which leads to membrane-mediated interactions. For a planar membrane under lateral tension, the interaction is repulsive for a pair of cylinders adhering to the same side of the membrane, and attractive for cylinders adhering at opposite membrane sides. For a membrane in an external harmonic potential, the interaction of adsorbed cylinders is always attractive and increases if forces perpendicular to the membrane act on the cylinders.

Weikl, T R

2003-01-01

242

Nuclear magnetic relaxation of adsorbed water  

Energy Technology Data Exchange (ETDEWEB)

The authors study a model of a heterodynamic system applied to the description of the proton magnetic relaxation of adsorbed water molecules. It is assumed that the relaxation times are determined by the spectral density of the correlation function of the stochastic motion of the molecules and that the spin dynamic is not affected by the heterodynamism. They study the proton magnetic relaxation of water adsorbed in large NaX zeolite cavities. The study of the temperature dependence of the spin-lattice, spin-spin, and proton relaxation times for this object became the basis for the Pfeifer-Gutsze-Zhdanov model.

Tsitsishvili, V.G.

1987-11-01

243

Process for producing granular algal adsorbents  

UK PubMed Central (United Kingdom)

A process is described for the production of granular algal adsorbents having an average particle size of 0.1 to 10 mm, wherein an aqueous solvent is added to a mixture of 5 to 90 parts by weight of activated carbon having a particle size not larger than 2 mm and 10 to 95 parts by weight of algal powder composed of Chlorella and/or Spiruline, followed by granulation and drying. Adsorbents made by this process are effective filters for the removal of toxic and odiferous materials in smoke and air and are particularly useful in cigarette filters.

TAKANASHI SEIZI

244

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

UK PubMed Central (United Kingdom)

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

Gómez-Pacheco CV; Rivera-Utrilla J; Sánchez-Polo M; López-Peñalver JJ

2012-05-01

245

Preparation, characterization and application of a Ce-Ti oxide adsorbent for enhanced removal of arsenate from water  

Energy Technology Data Exchange (ETDEWEB)

Different metal doped TiO{sub 2} adsorbents were prepared through the precipitation and hydrolysis-precipitation methods. The novel Ce-Ti oxide adsorbent obtained by the hydrolysis-precipitation had much higher sorption capacity for As(V) than both the pure titanium dioxide and cerium oxide adsorbents, and the preparation conditions including the Ti/Ce molar ratio and polyvinyl alcohol (PVA) content were optimized. Environmental scanning electronic microscopy (ESEM) and X-ray diffraction (XRD) spectroscopic investigations revealed that the amorphous Ce-Ti hybrid adsorbent was composed of some nanoparticles in the size range of 100-200 nm, which aggregated to form the porous hybrid adsorbents, and the amorphous compositions and the small nanoparticles were related to the high sorption capacity for As(V). Batch sorption experiments including sorption kinetics, isotherm, effect of pH and competitive ions were investigated. The Ce-Ti adsorbent exhibited high sorption capacity for As(V) at pH below 7. Column studies showed that about 72,085 bed volumes of As(V) solution at the concentration of 50 {mu}g L{sup -1} and pH 6.5 were filtered when As(V) concentration in the effluent increased to 10 {mu}g L{sup -1}, and the average sorption capacity of As(V) on the Ce-Ti adsorbent was about 9.4 mg g{sup -1}.

Deng Shubo, E-mail: dengshubo@tsinghua.edu.cn [POPs Research Center, Tsinghua University, Beijing 100084 (China); Department of Environmental Science and Engineering, Tsinghua University, Beijing 100084 (China); Li Zhijian; Huang Jun [POPs Research Center, Tsinghua University, Beijing 100084 (China); Department of Environmental Science and Engineering, Tsinghua University, Beijing 100084 (China); Yu Gang, E-mail: yg-den@tsinghua.edu.cn [POPs Research Center, Tsinghua University, Beijing 100084 (China); Department of Environmental Science and Engineering, Tsinghua University, Beijing 100084 (China)

2010-07-15

246

Preparation, characterization and application of a Ce-Ti oxide adsorbent for enhanced removal of arsenate from water  

International Nuclear Information System (INIS)

Different metal doped TiO2 adsorbents were prepared through the precipitation and hydrolysis-precipitation methods. The novel Ce-Ti oxide adsorbent obtained by the hydrolysis-precipitation had much higher sorption capacity for As(V) than both the pure titanium dioxide and cerium oxide adsorbents, and the preparation conditions including the Ti/Ce molar ratio and polyvinyl alcohol (PVA) content were optimized. Environmental scanning electronic microscopy (ESEM) and X-ray diffraction (XRD) spectroscopic investigations revealed that the amorphous Ce-Ti hybrid adsorbent was composed of some nanoparticles in the size range of 100-200 nm, which aggregated to form the porous hybrid adsorbents, and the amorphous compositions and the small nanoparticles were related to the high sorption capacity for As(V). Batch sorption experiments including sorption kinetics, isotherm, effect of pH and competitive ions were investigated. The Ce-Ti adsorbent exhibited high sorption capacity for As(V) at pH below 7. Column studies showed that about 72,085 bed volumes of As(V) solution at the concentration of 50 ?g L-1 and pH 6.5 were filtered when As(V) concentration in the effluent increased to 10 ?g L-1, and the average sorption capacity of As(V) on the Ce-Ti adsorbent was about 9.4 mg g-1.

1000-01-00

247

ZEOLITE CONTAINING WASH COATS FOR ADSORBER HEAT EXCHANGERS AND TEMPERATURE CONTROLLED ADSORBERS  

UK PubMed Central (United Kingdom)

The present invention provides a process for applying a coating on a heat exchanger or a temperature controlled adsorber surface. This coating comprises a zeolite, an organic solvent, an organic siloxane resin that constitutes a binder and a plasticizing agent.

DUNNE STEPHEN R; DUNNE PAMELA J; BERSHITSKY ALEXANDER M; PROSZOWSKI MARIOLA J

248

Dynamic analysis of a closed-cycle solar adsorption refrigerator using two adsorbent-adsorbate pairs  

Energy Technology Data Exchange (ETDEWEB)

In this paper a dynamic analysis of a closed-cycle, solar adsorption refrigerator is presented. The instantaneous and daily system performance are studied using two adsorbent-adsorbate pairs, Zeolite 13X-Water and Chabazite-Methanol. The effect of design and operating parameters, including inert material thermal capacitance, matrix porosity, and evaporation and condenser temperatures on the solar and cycle coefficients of performance are evaluated.

Hajji, A. (Inst. Agronomique et Veterinaire Hassan II, Dept. di Genie Industriel Alimentaire, Rabat-Inst. (MA)); Worek, W. (Mechanical Engineering Dept., Univ. of Illinois at Chicago, Chicago, IL (US)); Lavan, Z. (Mechanical Engineering Dept., Illinois Inst. of Technology, Chicago, IL (US))

1991-05-01

249

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

DEFF Research Database (Denmark)

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

Schnadt, Joachim; Xu, Wei

2010-01-01

250

Compound adsorbent for adsorption ice maker on fishing boats  

Energy Technology Data Exchange (ETDEWEB)

Adsorption performances of three types of adsorbents, CaCl{sub 2} with different expansion space, simple compound adsorbent and solidified compound adsorbent made by CaCl{sub 2} and activated carbon, are tested, in which ammonia is used as refrigerant. The solidified compound adsorbent shows the best performance for adsorption ice makers on fishing boats for the larger filling quantity of adsorbent in adsorber. The mass transfer performance is improved by the additive of activated carbon in solidified compound adsorbent at the condition of low evaporating temperature. The volume cooling density of solidified compound adsorbent is about 35% improved at least in comparison with the optimal results of CaCl{sub 2} at the evaporating temperature of -15{sup o}C. (author)

Wang, L.W.; Wang, R.Z.; Wu, J.Y.; Wang, K. [Shanghai Jiao Tong University (China). Institute of Refrigeration and Cryogenics

2004-06-01

251

EMERGING TECHNOLOGY SUMMARY: DEMONSTRATION OF AMBERSORB 563 ADSORBENT TECHNOLOGY  

Science.gov (United States)

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

252

Selective radium adsorbent and method of its production  

International Nuclear Information System (INIS)

The selective adsorbent consists of the hydrophilic cross-linked copolymer of acrylonitrile with acrylamide and/or acrylic acid. The polyacrylonitrile copolymer forms a matrix in which the active ingradient is dispersed, selectively adsorbing Ra2+ ions in the form of particulates, preferably colloidal. The procedure for adsorbent preparation is described. (J.P.)

1980-01-01

253

Non-Equilibrium in Adsorbed Polymer Layers  

CERN Multimedia

High molecular weight polymer solutions have a powerful tendency to deposit adsorbed layers when exposed to even mildly attractive surfaces. The equilibrium properties of these dense interfacial layers have been extensively studied theoretically. A large body of experimental evidence, however, indicates that non-equilibrium effects are dominant whenever monomer-surface sticking energies are somewhat larger than kT, a common case. Polymer relaxation kinetics within the layer are then severely retarded, leading to non-equilibrium layers whose structure and dynamics depend on adsorption kinetics and layer ageing. Here we review experimental and theoretical work exploring these non-equilibrium effects, with emphasis on recent developments. The structure and dynamics in non-equilibrium polymer layers adsorbed from dilute polymer solutions and from polymer melts and more concentrated solutions is discussed. Two distinct classes of behaviour arise, depending on whether physisorption or chemisorption is involved. A g...

O'Shaughnessy, B

2005-01-01

254

Zeolites as alcohol adsorbents from aqueous solutions  

Directory of Open Access Journals (Sweden)

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

Cekova Blagica; Kocev Dragi; Kolcakovska Elena; Stojanova Daniela

2006-01-01

255

Molecular simulation of adsorbed natural gas  

Energy Technology Data Exchange (ETDEWEB)

Absorbed natural gas is being investigated as a substitute for gasoline., The most important factor in engineering studies is the maximum storage capacity of adsorbents for natural gas. Monte Carlo calculations were performed to simulate the adsorption of natural gas on activated carbon. Adsorption isotherms, storage capacities, and isoteric heats were determined from simulations and compared with experimental data. Simulations predict a maximum storage capacity of 244 V/V at 35 atm.

Matranga, K.R.; Stella, A.; Myers, A.L.; Glandt, E.D. (Univ. of Pennsylvania, Philadelphia (United States))

1992-11-01

256

4He clusters adsorbed on graphene  

Science.gov (United States)

We report the results of a study of 4HeN clusters, for 2?N?40, adsorbed on one and both sides of a graphene sheet. The ground-state properties are determined using variational and diffusion Monte Carlo calculations at zero temperature, and in addition path integral Monte Carlo simulations at finite temperature are performed for some selected cluster sizes. For the interaction of helium atoms with graphene, we compare several models: a smooth He-graphene potential that depends only on the distance to the graphene sheet and potentials constructed as a sum of individual He-C interactions where two possibilities for this He-C interaction are tested. In this way, we assess the effect of corrugation on the binding properties of helium clusters. Furthermore, we study the influence that the graphene-mediated McLachlan dispersion energy has on the He-He interaction. The McLachlan interaction weakens the attraction between helium atoms, which turns out to have a significant effect on the binding energy and the shape of adsorbed 4He clusters. We find that clusters adsorbed on opposite sides of graphene are bound, but according to the He-He pair distribution function across the graphene sheet, pair correlations are very weak. For a large enough number of particles, solidlike 3×3 structures start to become energetically preferred for the model of anisotropic corrugation without the McLachlan interaction. For the other models, the ground state of the studied clusters is clearly liquidlike.

Vranješ Marki?, L.; Stipanovi?, P.; Bešli?, I.; Zillich, R. E.

2013-09-01

257

A novel adsorbent photocatalyst consisting of titania and mesoporous silica nanoparticles  

International Nuclear Information System (INIS)

The nanoscale combination of crystalline titania and mesoporous silica particles was successfully applied as a photocatalytic adsorbent for the rapid removal from air and complete decomposition of organic molecules. The composites consisted of anatase particles ca. 7 nm in diameter and mesoporous silica particles 10-100 nm in diameter, which provided a specific surface area of more than 1000 m2/g. The composites were prepared through the assembly of surfactant micelles and siliceous species in the presence of the titania nanoparticles. Acetaldehyde was quickly removed from air due to the large surface area of the mesoporous silica and then was gradually decomposed into carbon dioxide under UV illumination with mass transfer between the adsorbent and the titania photocatalyst.

2005-11-25

258

Product development studies on surface-adsorbed nanoemulsion of olmesartan medoxomil as a capsular dosage form.  

Science.gov (United States)

The present study aimed at development of capsular dosage form of surface-adsorbed nanoemulsion (NE) of olmesartan medoxomil (OLM) so as to overcome the limitations associated with handling of liquid NEs without affecting their pharmaceutical efficacy. Selection of oil, surfactant, and cosurfactant for construction of pseudoternary phase diagrams was made on the basis of solubility of drug in these excipients. Rationally selected NE formulations were evaluated for percentage transmittance, viscosity, refractive index, globule size, zeta potential, and polydispersity index (PDI). Formulation (F3) comprising of Capmul MCM® (10% v/v), Tween 80® (11.25% v/v), polyethylene glycol 400 (3.75% v/v), and double-distilled water (75% v/v) displayed highest percentage cumulative drug release (%CDR; 96.69?±?1.841), least globule size (17.51?±?5.87 nm), low PDI (0.203?±?0.032), high zeta potential (-58.93?±?0.98 mV), and hence was selected as the optimized formulation. F3 was adsorbed over colloidal silicon dioxide (2 ml/400 mg) to produce free-flowing solid surface-adsorbed NE that presented a ready-to-fill capsule composition. Conversion of NE to surface-adsorbed NE and its reconstitution to NE did not affect the in vitro release profile of OLM as the similarity factor with respect to NE was found to be 66% and 73% respectively. The %CDR after 12 h for optimized NE, surface-adsorbed NE, and reconstituted NE was found to be 96.69?±?0.54, 96.07?±?1.76, and 94.78?±?1.57, respectively (p?>?0.05). The present study established capsulated surface-adsorbed NE as a viable delivery system with the potential to overcome the handling limitations of NE. PMID:22965661

Singh, Sumita; Pathak, Kamla; Bali, Vikas

2012-09-11

259

Product development studies on surface-adsorbed nanoemulsion of olmesartan medoxomil as a capsular dosage form.  

UK PubMed Central (United Kingdom)

The present study aimed at development of capsular dosage form of surface-adsorbed nanoemulsion (NE) of olmesartan medoxomil (OLM) so as to overcome the limitations associated with handling of liquid NEs without affecting their pharmaceutical efficacy. Selection of oil, surfactant, and cosurfactant for construction of pseudoternary phase diagrams was made on the basis of solubility of drug in these excipients. Rationally selected NE formulations were evaluated for percentage transmittance, viscosity, refractive index, globule size, zeta potential, and polydispersity index (PDI). Formulation (F3) comprising of Capmul MCM® (10% v/v), Tween 80® (11.25% v/v), polyethylene glycol 400 (3.75% v/v), and double-distilled water (75% v/v) displayed highest percentage cumulative drug release (%CDR; 96.69?±?1.841), least globule size (17.51?±?5.87 nm), low PDI (0.203?±?0.032), high zeta potential (-58.93?±?0.98 mV), and hence was selected as the optimized formulation. F3 was adsorbed over colloidal silicon dioxide (2 ml/400 mg) to produce free-flowing solid surface-adsorbed NE that presented a ready-to-fill capsule composition. Conversion of NE to surface-adsorbed NE and its reconstitution to NE did not affect the in vitro release profile of OLM as the similarity factor with respect to NE was found to be 66% and 73% respectively. The %CDR after 12 h for optimized NE, surface-adsorbed NE, and reconstituted NE was found to be 96.69?±?0.54, 96.07?±?1.76, and 94.78?±?1.57, respectively (p?>?0.05). The present study established capsulated surface-adsorbed NE as a viable delivery system with the potential to overcome the handling limitations of NE.

Singh S; Pathak K; Bali V

2012-12-01

260

Electron spin resonance study of nitric oxide adsorbed in Na-A zeolite  

Energy Technology Data Exchange (ETDEWEB)

The ESR spectrum of NO adsorbed in Na-A zeolite was reexamined. Unlike ESR spectra of NO observed earlier with other zeolites, the ESR spectrum of NO monomer in Na-A zeolite was found to be well-defined and resolved, reflecting the compositional uniformity (Si/Al ratio of 1) of the material. The study also revealed the formation of an unusual NO-NO triplet species within the cavities.

Kasal, P.H.; Gaura, R.M.

1982-10-14

 
 
 
 
261

Removal of adsorbent particles od copper ions by Jet flotation  

International Nuclear Information System (INIS)

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

2009-01-01

262

Photolysis of polycyclic aromatic hydrocarbons adsorbed on fly ash  

Energy Technology Data Exchange (ETDEWEB)

Polycyclic aromatic hydrocarbons (PAH) are formed by the combustion of almost any fuel under oxygen-deficient conditions. Previous laboratory studies have found that many PAH degrade with lifetimes as short as a few hours; however, studies of marine and lacustrine sediments, the ultimate sinks of PAH, have shown relative abundances of PAH which are similar to those in combustion sources; this suggests that PAH are stable in the atmosphere. Eighteen PAH adsorbed on carbon black and fifteen coal fly ashes of varying physical and chemical composition were photolyzed in order to study their atmospheric fate. Photolytic half-lives for these particle-bound PAH were found to be highly dependent on the substrate onto which they were adsorbed. On low-carbon fly ash, PAH showed a wide range of half-lives, indicating a relationship between PAH structure and photochemical reactivity. However, PAH on carbon black and fly ashes with a high-carbon content, show similar half-lives for most PAH including reactive PAH such as anthracene and benzo(a)pyrene. This indicates a photolytic process that is independent of structure and dependent on the physical and chemical nature of the fly ash. Surprisingly, no other parameter accounts for observed PAH reactivity. Substrate characteristics such as surface area, porosity, particle size, surface pH, and iron content have all been suggested to influence the rate of PAH degradation. However, these parameters, measured for substrates studied in this thesis, do not correlate with PAH reactivity. Because carbon black and high-carbon fly ashes stabilize reactive PAH, it is these substrates which would facilitate the transport of PAH from combustion sources through the atmosphere to ultimate sinks.

Behymer, T.D.

1987-01-01

263

Structured fixed-bed adsorber based on zeolite/sintered metal fibre for low concentration VOC removal  

Digital Repository Infrastructure Vision for European Research (DRIVER)

A novel adsorber with a structured fixed-bed made of sintered metal fibres (SMF) plates has been developed for purification of low-content VOCs gas-streams. The surface of the metal fibres was coated by a thin, homogeneous MFI-type (ZSM-5, Silicalite-1) zeolite film. The zeolite/SMF composite has be...

Nikolajsen, K; Kiwi-Minsker, L; Renken, A

264

Lead removal with adsorbing colloid flotation  

Energy Technology Data Exchange (ETDEWEB)

A process that removes lead from industrial waste by adsorbing colloid foam flotation has been designed and demonstrated. A system of ferric chloride and sodium lauryl sulfate, both relatively inexpensive chemicals, gave good performance with optimum dosages of sodium lauryl sulfate at 40 mg/l and trivalent iron at 150 mg/l. With optimum chemical and hydraulic conditions, the pilot plant was able to produce effluents with lead concentrations of less than 0.5 mg/l. The process may be especially attractive where space for heavy metals removal equipment is extremely limited.

Thackston, E.L.; Wilson, D.J.; Hanson, J.S.; Miller, D.L. Jr.

1980-02-01

265

Stability constants for silicate adsorbed to ferrihydrite  

DEFF Research Database (Denmark)

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

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

1994-01-01

266

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

Energy Technology Data Exchange (ETDEWEB)

Investigations of the properties of absorbed monolayers have received great experimental and theoretical attention recently, both because of the importance of surface processes in practical applications such as catalysis, and the importance of such systems to the understanding of the fundamentals of thermodynamics in two dimensions. We have adapted the composite bolometer technology to the construction of microcalorimeters. For these calorimeters, the adsorption substrate is an evaporated film deposited on one surface of an optically polished sapphire wafer. This approach has allowed us to make the first measurements of the heat capacity of submonolayer films of /sup 4/He adsorbed on metallic films. In contrast to measurements of /sup 4/He adsorbed on all other insulating substrates, we have shown that /sup 4/He on silver films occupies a two-dimensional gas phase over a broad range of coverages and temperatures. Our apparatus has been used to study the heat capacity of Indium flakes. CO multilayers, /sup 4/He adsorbed on sapphire and on Ag films and H/sub 2/ adsorbed on Ag films. The results are compared with appropriate theories. 68 refs., 19 figs.

Kenny, T.W.

1989-05-01

267

Modeling adsorption properties on the basis of microscopic, molecular, and structural descriptors for nonpolar adsorbents.  

UK PubMed Central (United Kingdom)

We propose a method for analytically predicting single-component adsorption isotherms from molecular, microscopic and structural descriptors of the adsorbate-adsorbent system and concepts of statistical thermodynamics. Expressions for Henry's constant and the heat of adsorption at zero coverage are derived. These functions depend on the pore size, pore shape, chemical composition, and density of the adsorbent material. They quantify the strength of the solid-fluid interaction, which governs the low-pressure part of the adsorption isotherm. For intermediate and high pressures, the fluid-fluid interactions must also be taken into account. Both solid-fluid and fluid-fluid interactions are combined within the framework of the Ruthven statistical model (RSM). The RSM thus constructs theoretical adsorption isotherms that are entirely based on microscopic molecular and structural descriptors. The theoretical results that we obtained are compared with experimental data for the adsorption of pure CO2 and CH4 on all-silica zeolites. The developed methodology allows for the estimation of the optimum properties of a nonpolar adsorbent for the adsorption of CO2 in cyclic adsorption processes.

García EJ; Pérez-Pellitero J; Jallut C; Pirngruber GD

2013-07-01

268

Comparison of Lead Removal by Various Types of Swine Bone Adsorbents  

Directory of Open Access Journals (Sweden)

Full Text Available The removal capacities of lead by bone adsorbents, prepared in various appropriate types, have been studied in a single component system using agitated batch sorption. The adsorbent characteristics before and after sorption were examined by electron microscopy, surface area analysis (BET), crystalline structure by x-ray diffractometer (XRD), chemical compositions by x-ray fluorescence (XRF) and by Fourier transform infrared (FT-IR). The results showed that the main component of swine bone adsorbents is calcium hydroxyl¬apatite with Ca/P ratio is 1.70; the calcium ion and the range of mesopores of the appropriate pore sizes are the important factors for the ion-exchange process and the sorption process. The effects of carbonization, activation, initial metal ion solution concentration, contact time and quantities of bone adsorbent mass were studied. The capacity removal of lead onto bone powder, bone char and activated bone char were 417, 1828 and 690 mg/g, respectively, for 10 mg/L and pH 5±0.1 of the initial lead ion solution concentration, with an agitation speed 175 rpm. The sorption isotherm was also studied and indicated that the Langmuir isotherm model closely fits the sorbtion of lead onto bone char.

Sudaratn Lurtwitayapont

2010-01-01

269

Correlation and prediction of liquid-phase adsorption on zeolites using group contributions based on adsorbate-solid solution theory  

Energy Technology Data Exchange (ETDEWEB)

Both correlation as well as prediction of experimental data for the adsorption of various binary liquid mixtures of alkanes and alkenes on NaX at different temperatures are presented. The theoretical background is based on the adsorbate-solid solution theory which conceives the adsorbed phase to be a mixture of the adsorbed species (adsorbate) and the adsorbent as an additional component. With the introduction of the Gibbs excess energy G{sup E*} for this hypothetical mixture, activity coefficients and composition of the adsorbed phase may be calculated. The Biggs excess energy and thus the activity coefficient of the adsorbed species depend strongly on the energetic heterogeneity of the solid surface which may be described by use of so-called group contribution models. These approaches, until now widely applied to predict fluid-phase equilibrium, are derived from statistical thermodynamics and take into account the energetic interactions between the respective components. For the application of this approach on thermodynamics of adsorption zeolites have to be divided into different functional groups such as SiO{sub 2}, AlO{sub 2}{sup {minus}}, and the respective cations. The interaction energies between these active sites and the functional groups of the adsorbed liquid molecules represent fundamental parameters of activity coefficient models based on group contributions such as UNIFAC. These parameters were determined by fitting four different adsorption systems. With the fitted values, six other systems were predicted. Both correlation and prediction include adsorption data at different temperatures. All calculations show excellent results with a mean relative deviation of 4.2% for the correlation and a mean deviation in the range of 8--17% for the predictions.

Berti, C.; Ulbig, P.; Burdorf, A.; Seippel, J.; Schulz, S.

1999-08-31

270

Application of bifunctional magnetic adsorbent to adsorb metal cations and anionic dyes in aqueous solution  

International Nuclear Information System (INIS)

[en] A magnetic adsorbent, amine-functionalized silica magnetite (NH2/SiO2/Fe3O4), has been synthesized to behave as an anionic or cationic adsorbent by adjusting the pH value of the aqueous solution to make amino groups protonic or neutral. NH2/SiO2/Fe3O4 were used to adsorb copper ions (metal cation) and Reactive Black 5 (RB5, anionic dye) in an aqueous solution in a batch system, and the maximum adsorption were found to occur at pH 5.5 and 3.0, respectively. The adsorption equilibrium data were all fitted the Langmuir isotherm equation reasonably well, with a maximum adsorption capacity of 10.41 mg g-1 for copper ions and of 217 mg g-1 for RB5. A pseudo-second-order model also could best describe the adsorption kinetics, and the derived activation energy for copper ions and RB5 were 26.92 kJ mol-1 and 12.06 kJ mol-1, respectively. The optimum conditions to desorb cationic and anionic adsorbates from NH2/SiO2/Fe3O4 were provided by a solution with 0.1 M HNO3 for copper ions and with 0.05 M NaOH for RB5.

2011-01-30

271

Iodine adsorbent handling method and device therefor  

Energy Technology Data Exchange (ETDEWEB)

After filling spent silver compound-added iodine adsorbent into a storage vessel, oxygen and inert gas are injected while exhausting gases in the storage vessel. In this case, an oxygen partial pressure in the storage vessel is measured by using a pressure gauge and an oxygen densitometer connected to an oxygen partial pressure measuring nozzle, and the inert gas and oxygen are kept to be injected till the partial pressure is increased to more than 1.92 x 10{sup -4} atm. After the oxygen partial pressure reaches the level, an oxygen nozzle, an inner gas exhaustion nozzle and the oxygen partial pressure measuring nozzle are sealed by plugs. Since the iodine adsorbent can be maintained in an atmosphere of higher than a reduction potential of silver ions, occurrence of a reducing reaction, namely, 2AgI {yields} 2Ag + I{sub 2} can be prevented to prevent iodine from releasing again. Namely, the leakage of iodine during storage and transporting steps can be prevented directly by using a simple method. (T.M.)

Watanabe, Shin-ichi; Kondo, Yoshikazu; Fukazawa, Tetsuo

1996-11-29

272

Iodine adsorbent handling method and device therefor  

International Nuclear Information System (INIS)

After filling spent silver compound-added iodine adsorbent into a storage vessel, oxygen and inert gas are injected while exhausting gases in the storage vessel. In this case, an oxygen partial pressure in the storage vessel is measured by using a pressure gauge and an oxygen densitometer connected to an oxygen partial pressure measuring nozzle, and the inert gas and oxygen are kept to be injected till the partial pressure is increased to more than 1.92 x 10-4 atm. After the oxygen partial pressure reaches the level, an oxygen nozzle, an inner gas exhaustion nozzle and the oxygen partial pressure measuring nozzle are sealed by plugs. Since the iodine adsorbent can be maintained in an atmosphere of higher than a reduction potential of silver ions, occurrence of a reducing reaction, namely, 2AgI ? 2Ag + I2 can be prevented to prevent iodine from releasing again. Namely, the leakage of iodine during storage and transporting steps can be prevented directly by using a simple method. (T.M.).

1995-05-22

273

Hexavalent chromium removal using indigenously developed adsorbents  

International Nuclear Information System (INIS)

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

2007-01-01

274

Separation and Recovery of Tetramethyl Ammonium Hydroxide with Zeolitic Adsorbents  

Directory of Open Access Journals (Sweden)

Full Text Available Separation and recovery of tetramethyl ammonium hydroxide (TMAH) has been investigated, employing several zeolites as adsorbents. Zeolite X, prepared by using TMAH as a structure directing agent, possesses highest adsorption ability among the adsorbents investigated in the present work, which corresponds to the specific surface area and pore volume of the zeolite. The adsorption amount of TMAH with the zeolitic adsorbents increases with increase in pH value in the aqueous solution, indicating the adsorption progresses via cation exchange mechanism. The chromatographic operation is finally conducted, using granulated zeolitic adsorbents to prevent from the pressure-drop, and the quantitative adsorption-elution processing of TMAH can be achieved.

Nishihama, S.; Takatori, K.; Yoshizuka, K.

2010-01-01

275

The existing forms of adsorbed Cr in sediment  

International Nuclear Information System (INIS)

The existing forms of adsorbed Cr and the effect of pH value and Cr(VI) concentration on the forms were studied by using sequential extraction and isotopic tracer technique. It was shown that the order of Cr adsorbed in different phases was Fe/Mn oxide > organic, and carbonate > residual > exchangeable. Adsorption of Cr in sediment was controlled by Cr(VI) concentration and pH value, but the distribution of Cr adsorbed in various phases was independent of these factors. Fe/Mn oxide and organic matter were the main adsorbent of Cr in sediment.

1995-01-01

276

Carbonaceous adsorbent regeneration and halocarbon displacement by hydrocarbon gases  

Energy Technology Data Exchange (ETDEWEB)

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

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

1994-01-01

277

Carbonaceous adsorbent regeneration and halocarbon displacement by hydrocarbon gases  

Energy Technology Data Exchange (ETDEWEB)

This invention describes a process for regeneration of halocarbon bearing carbonaceous adsorbents through which a carbonaceous adsorbent is contacted with hydrocarbon gases, preferably propane, butane and pentane at near room temperatures and at atmospheric pressure. As the hydrocarbon gases come in contact with the adsorbent, the hydrocarbons displace the halocarbons by physical adsorption. As a result of using this process, the halocarbon concentration and the hydrocarbon eluant is increased thereby allowing for an easier recovery of pure halocarbons. By using the process of this invention, carbonaceous adsorbents can be regenerated by an inexpensive process which also allows for subsequent re-use of the recovered halocarbons. 8 figures.

Senum, G.I.; Dietz, R.N.

1994-04-05

278

Theoretical insight of physical adsorption for a single-component adsorbent+adsorbate system: I. Thermodynamic property surfaces.  

Science.gov (United States)

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) CaCl2-in-silica gel+water system for cooling applications, and (ii) activated carbon (Maxsorb III)+methane system for gas storage. PMID:19140706

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

2009-02-17

279

Theoretical insight of physical adsorption for a single-component adsorbent+adsorbate system: I. Thermodynamic property surfaces.  

UK PubMed Central (United Kingdom)

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) CaCl2-in-silica gel+water system for cooling applications, and (ii) activated carbon (Maxsorb III)+methane system for gas storage.

Chakraborty A; Saha BB; Ng KC; Koyama S; Srinivasan K

2009-02-01

280

Testing of chemically treated adsorbent air purifiers  

Energy Technology Data Exchange (ETDEWEB)

New highly sensitive continuous monitors permit testing of air filters at parts-per-billion contaminant concentrations. This article describes testing of air purification filters intended for use in the National Archives 2 building in College Park, Maryland, using a test procedure that simulates the actual conditions of use. This test demonstrates both the effectiveness of the adsorbers at low contaminant levels, and the capability of existing instruments for conducting such tests. ASHRAE TC 2.3 (Gaseous Air Contaminants and Gas Contaminant Removal Equipment) is currently sponsoring research projects (follow-on studies to ASHRAE Project RP-674) aimed at developing a standard that will test and rate the performance of different types of gas phase air purification equipment at low concentrations. The work detailed in this article represents a first of this type of testing and a technical benchmark that may aid in the further development of ASHRAE gas phase performance standards.

Kelly, T.J. (Battelle Memorial Inst., Columbus, OH (United States). Dept. of Atmospheric Science and Applied Technology); Kinkead, D.A. (Extraction Systems Inc., Woonsocket, RI (United States))

1993-07-01

 
 
 
 
281

Utilization of Waste Eggshells as Humidity Adsorbent  

Directory of Open Access Journals (Sweden)

Full Text Available The chicken and duck eggshell powders were prepared and heated at 1300C for 4 h. The samples were analyzed by X-Ray Diffraction (XRD). It was found that Calcium Carbonate (CaCO3) from chicken and duck eggshells completely transformed into Calcium Oxide (CaO). Then the samples were placed in a box installed with a hygro-thermometer for humidity adsorption test in the range of 20-75% RH at 25C. Hydration rate for duck and chicken eggshells were 0.0625% RH min-1 (within 880 min) and 0.0482% RH min-1 (within 1140 min) respectively. The results show that CaO from the duck eggshells is a better adsorbent than that of chicken eggshells. Furthermore, after humidity adsorption, CaO obtained from both eggshells were partly transformed into portlandite (Ca(OH)2 was confirmed by the Rietveld refinement method and Scanning Electron Microscope (SEM).

P. Pongtonglor; E. Hoonnivathana; P. Limsuwan; S. Limsuwan; K. Naemchanthara

2011-01-01

282

Conformation of adsorbed comb copolymer dispersants.  

UK PubMed Central (United Kingdom)

Comb copolymers with an adsorbing backbone and nonadsorbing side chains can be very effective dispersants, particularly when a high ionic strength strongly penalizes electrostatic stabilization. For this reason, they have become essential components of concrete over the past decade. This article examines the steric hindrance characteristics of such polymers through the use of atomic force microscopy (AFM) on calcium silicate hydrate, the main hydration product of Portland cement. It is found that solution and surface properties (hydrodynamic radius, radius of gyration, surface coverage, steric layer thickness) and force-distance curves obtained during AFM measurements can be well described by a scaling approach derived in this paper. This represents the first real quantitative step in relating these properties directly to the molecular structure of such comb copolymer dispersants.

Flatt RJ; Schober I; Raphael E; Plassard C; Lesniewska E

2009-01-01

283

Quantum surface diffusion of interacting adsorbates  

CERN Document Server

A quantum atom-surface diffusion model with interacting adsorbates is proposed to the intermediate scattering function. Within this model, the intermediate scattering function is shown to be complex-valued and factorizable into a classical-like and a quantum-mechanical part. Applications to the diffusion of Na atoms on flat and corrugated Cu(001) surfaces at different coverages and surface temperatures are analyzed. As shown, quantum effects are relevant to diffusion at low surface temperatures and coverages even for relatively heavy particles, such as Na atoms. Below 100 K, the corresponding calculations are particularly appropriate to also obtain jump mechanisms and peak positions of the low-frequency frustrated translational modes and friction coefficients, commonly extracted from extrapolation to zero temperature.

Martinez-Casado, R; Miret-Artés, S

2008-01-01

284

Nanopatterned monolayers of an adsorbed chromophore.  

UK PubMed Central (United Kingdom)

A simple lift-off process was developed to rapidly fabricate nanopatterned photofunctional surfaces. Dye molecules of a perylene derivative (PDID) were adsorbed irreversibly on clean silicon through the holes of an electron-beam lithographied polymer mask. The subsequent removal of the mask in a proper solvent results in PDID nanosized regions of width as small as 30 nm for stripes and of diameter as small as 120 nm for dots. Numerical analyses of atomic force microscopy and laser-scanning confocal microscopy images show that the dye molecules are confined to the regions defined by the lithographic process, with the integrated fluorescence intensity being essentially proportional to the size of the nanofeatures. This demonstrates that a simple organic lift-off process compatible with clean-room technology, and not involving any chemical step, is able to produce photofunctional nanopatterned surfaces, even though the dye is not chemically bonded to the silicon surface.

Frederich N; Nysten B; Duwez AS; Muls B; Hofkens J; Jonas AM; Habib-Jiwan JL

2008-08-01

285

Nanopatterned monolayers of an adsorbed chromophore  

Energy Technology Data Exchange (ETDEWEB)

A simple lift-off process was developed to rapidly fabricate nanopatterned photofunctional surfaces. Dye molecules of a perylene derivative (PDID) were adsorbed irreversibly on clean silicon through the holes of an electron-beam lithographied polymer mask. The subsequent removal of the mask in a proper solvent results in PDID nanosized regions of width as small as 30 nm for stripes and of diameter as small as 120 nm for dots. Numerical analyses of atomic force microscopy and laser-scanning confocal microscopy images show that the dye molecules are confined to the regions defined by the lithographic process, with the integrated fluorescence intensity being essentially proportional to the size of the nanofeatures. This demonstrates that a simple organic lift-off process compatible with clean-room technology, and not involving any chemical step, is able to produce photofunctional nanopatterned surfaces, even though the dye is not chemically bonded to the silicon surface.

Frederich, N; Nysten, B; Jonas, A M [Unite de Physique et de Chimie des hauts Polymeres, Universite Catholique de Louvain, Croix du Sud 1, B-1348 Louvain-la-Neuve (Belgium); Duwez, A-S [NanoChemistry and Molecular Systems, Department of Chemistry, University of Liege, B6a Sart-Tilman, B-4000 Liege (Belgium); Muls, B; Habib-Jiwan, J-L [Unite de Chimie des Materiaux Organiques et Inorganiques, Universite Catholique de Louvain, Place Louis Pasteur 1, B-1348 Louvain-la-Neuve (Belgium); Hofkens, J [Department of Chemistry, Katholieke Universiteit Leuven, Celestijnenlaan 200F, 3001 Heverlee (Belgium)

2008-08-20

286

Adsorbed and Grafted Polymers at Equilibrium  

CERN Document Server

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

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

2000-01-01

287

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

DEFF Research Database (Denmark)

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.

Grabow, Lars; Larsen, Britt Hvolbæk

2010-01-01

288

Thermodynamic study of fatty acids adsorption on different adsorbents  

International Nuclear Information System (INIS)

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

2007-01-01

289

Anhydrous topical formulation for polyphenols adsorbed to binding carrier  

UK PubMed Central (United Kingdom)

Disclosed is a composition of matter, and method to formulate same, which is an anhydrous topical cream, gel or ointment base, a polyphenol and a suitable adsorbent binding carrier to which the polyphenol will bind for purposes of even disbursement within the cream, gel or base and which will not inhibit the ability of the polyphenols to be released on and into the aqueous environment of the skin when the topical mixture is applied thereto. The binding carrier provides the ability to disperse a hydrophilic polyphenol in a non-aqueous medium for purposes of topical application to the body. In particular, the present disclosure relates to the use of polyphenols such as tea catechins, and in particular green tea catechins, disbursed in an anhydrous base consisting of either saturated or unsaturated plant oils or waxes through the use of a variety of binding carriers including, but is not limited to, talcs and clays, alginates, algae, agars, gums, gelatins, celluloses, silica, silica gels, simethicone, salicylates, silicates and silicone resins, tragacanths, calcium carbonates and magnesium or zinc oxides. Such binding carriers are particularly useful when polyphenol concentrations exceed 0.2% w/w in the mixture, and their use is preferred when concentrations are between 1.0 to 20% w/w polyphenols.

BUDERER MATHEW; FORD PETER; ROENTCSH GEORGE; CERVELLI ROBERT; JOYCE HEATHER

290

Application of bifunctional magnetic adsorbent to adsorb metal cations and anionic dyes in aqueous solution  

Energy Technology Data Exchange (ETDEWEB)

A magnetic adsorbent, amine-functionalized silica magnetite (NH{sub 2}/SiO{sub 2}/Fe{sub 3}O{sub 4}), has been synthesized to behave as an anionic or cationic adsorbent by adjusting the pH value of the aqueous solution to make amino groups protonic or neutral. NH{sub 2}/SiO{sub 2}/Fe{sub 3}O{sub 4} were used to adsorb copper ions (metal cation) and Reactive Black 5 (RB5, anionic dye) in an aqueous solution in a batch system, and the maximum adsorption were found to occur at pH 5.5 and 3.0, respectively. The adsorption equilibrium data were all fitted the Langmuir isotherm equation reasonably well, with a maximum adsorption capacity of 10.41 mg g{sup -1} for copper ions and of 217 mg g{sup -1} for RB5. A pseudo-second-order model also could best describe the adsorption kinetics, and the derived activation energy for copper ions and RB5 were 26.92 kJ mol{sup -1} and 12.06 kJ mol{sup -1}, respectively. The optimum conditions to desorb cationic and anionic adsorbates from NH{sub 2}/SiO{sub 2}/Fe{sub 3}O{sub 4} were provided by a solution with 0.1 M HNO{sub 3} for copper ions and with 0.05 M NaOH for RB5.

Lin, Ya-Fen [Department of Chemical and Materials Engineering, National I-Lan University, I-Lan 260, Taiwan (China); Chen, Hua-Wei [Department of Cosmetic Application and Management, St. Mary' s Medicine Nursing and Management College, I-Lan, Taiwan (China); Chien, Poh-Sun [Department of Environmental Engineering, National I-Lan University, 1, Sec. 1, Shen-Lung Road, I-Lan, 260, Taiwan (China); Chiou, Chyow-San, E-mail: cschiou@niu.edu.tw [Department of Environmental Engineering, National I-Lan University, 1, Sec. 1, Shen-Lung Road, I-Lan, 260, Taiwan (China); Liu, Cheng-Chung [Department of Environmental Engineering, National I-Lan University, 1, Sec. 1, Shen-Lung Road, I-Lan, 260, Taiwan (China)

2011-01-30

291

Certain Peculiarities of the Raman Spectra of Adsorbed Molecules.  

Science.gov (United States)

In view of the fact that Raman spectra of compounds adsorbed on surfaces of glass, silica gel, and alumosilica gel has not been studied before, and in view of the additional information that Raman spectra can yield on the vibrational spectra of the adsorb...

E. V. Pershina S. S. Raskin

1971-01-01

292

Development of a Desulfurization Strategy for a NOx Adsorber Catalyst  

Energy Technology Data Exchange (ETDEWEB)

Improve NOx regeneration calibration developed in DECSE Phase I project to understand full potential of NOx adsorber catalyst over a range of operating temperatures. Develop and demonstrate a desulfurization process to restore NOx conversion efficiency lost to sulfur contamination. Investigate effect of desulfurization process on long-term performance of the NOx adsorber catalyst.

Tomazic, Dean

2000-08-20

293

Nature, strength, and consequences of indirect adsorbate interactions on metals  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Atoms and molecules adsorbed on metals affect each other indirectly even over considerable distances. Via systematic density-functional calculations, we establish the nature and strength of such interactions, and explain for what adsorbate systems they critically affect important materials propertie...

Bogicevic, A.; Ovesson, S.; Hyldgaard, P.; Lundqvist, B. I.; Brune, H.; Jennison, D. R.

294

A nuclear standard high-efficiency adsorber for iodine  

International Nuclear Information System (INIS)

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%

1988-01-01

295

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

International Nuclear Information System (INIS)

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

2005-05-15

296

Analysis and comparison of inertinite-derived adsorbent with conventional adsorbents.  

UK PubMed Central (United Kingdom)

To increase U.S. petroleum energy-independence, the University of Texas at Arlington (UT Arlington) has developed a coal liquefaction process that uses a hydrogenated solvent and a proprietary catalyst to convert lignite coal to crude oil. This paper reports on part of the environmental evaluation of the liquefaction process: the evaluation of the solid residual from liquefying the coal, called inertinite, as a potential adsorbent for air and water purification. Inertinite samples derived from Arkansas and Texas lignite coals were used as test samples. In the activated carbon creation process, inertinite samples were heated in a tube furnace (Lindberg, Type 55035, Arlington, UT) at temperatures ranging between 300 and 850 degrees C for time spans of 60, 90, and 120 min, using steam and carbon dioxide as oxidizing gases. Activated inertinite samples were then characterized by ultra-high-purity nitrogen adsorption isotherms at 77 K using a high-speed surface area and pore size analyzer (Quantachrome, Nova 2200e, Kingsville, TX). Surface area and total pore volume were determined using the Brunauer Emmet, and Teller method, for the inertinite samples, as well as for four commercially available activated carbons (gas-phase adsorbents Calgon Fluepac-B and BPL 4 x 6; liquid-phase adsorbents Filtrasorb 200 and Carbsorb 30). In addition, adsorption isotherms were developed for inertinite and the two commercially available gas-phase carbons, using methyl ethyl ketone (MEK) as an example compound. Adsorption capacity was measured gravimetrically with a symmetric vapor sorption analyzer (VTI, Inc., Model SGA-100, Kingsville, TX). Also, liquid-phase adsorption experiments were conducted using methyl orange as an example organic compound. The study showed that using inertinite from coal can be beneficially reused as an adsorbent for air or water pollution control, although its surface area and adsorption capacity are not as high as those for commercially available activated carbons. Implications: The United States currently imports two-thirds of its crude oil, leaving its transportation system especially vulnerable to disruptions in international crude supplies. UT Arlington has developed a liquefaction process that converts coal, abundant in the United States, to crude oil. This work demonstrated that the undissolvable solid coal residual from the liquefaction process, called inertinite, can be converted to an activated carbon adsorbent. Although its surface area and adsorption capacity are not as high as those for commercially available carbons, the inertinite source material would be available at no cost, and its beneficial reuse would avoid the need for disposal.

Gangupomu RH; Kositkanawuth K; Sattler ML; Ramirez D; Dennis BH; MacDonnell FM; Billo R; Priest JW

2012-05-01

297

Pyrolyzed feather fibers for adsorbent and high temperature applications  

Science.gov (United States)

Chicken feather fibers (CFF) are problematic and costly for the poultry industry in terms of managing maintenance and disposal. Considering their great availability, low cost, and unique protein structure, CFF can be an environmentally friendly and bio-renewable candidate to replace petroleum products. CFF's low degradation and melting temperature render them useless at high temperatures. Pyrolysis methods were developed for CFF by using two temperature steps to convert them into high temperature resistant and adsorbent fibers while retaining their original physical appearance and affine dimensions. An intermolecular crosslinking mechanism in the first step of pyrolysis at 215 ºC for 24 h provided an intact fibrous structure with no subsequent melting. The evidence obtained from the thermal, bulk, and surface analysis techniques was indication of the simultaneous side chain degradation, polypeptide backbone scission, disulfide bond cleavage, and isopeptide crosslinking. The variation in the reaction kinetics of disulfide bond cleavage and isopeptide crosslinking played an important role in the melting transition. Consequently, long-lasting heat treatments below the melting point provided sufficient crosslinks in the protein matrix to keep the fibrous structure intact. Water-insoluble and crosslinked CFF reinforced the triglyceride-fatty acid based composites by providing a 15 fold increase in storage and tensile modulus at room temperature. These thermally stable fibers can be used instead of CFF in composites which may require high temperature compounding and molding processes. The second step of pyrolysis at 400--450 ºC for 1 h resulted in microporous fibers with a micropore volume of ˜0.18 cm3/g STP and with a narrower pore size distribution than commercial activated carbons through thermal degradation. Nearly all accessible pores in the microporous pyrolyzed chicken feather fibers (PCFF) had diameters less than 1 nm and therefore, showed a potential to be used in applications such as adsorption, storage, and separation of small gas molecules. The maximum excess H2 storage capacity was 1.5 wt% at 77 K and at pressures below 2 MPa. The notable H2 adsorption of PCFF below 1 MPa can be justified by the abundance of microporosity and the nanopores available for H2 penetration. In the second step of the pyrolysis the protein matrix went through a series of transformations including cyclization and aromatization reactions above the melting point. A partially cyclic carbon-nitrogen framework (carbon/nitrogen ratio=2.38) supported by double and triple bonds and oxygen functionalities is the suggested structural model for the PCFF. The useful fibers and adsorbents produced from CFF in this dissertation can encourage researchers to use high temperature heat treatments on keratin-based fibers. Also, the identified pyrolysis mechanisms can serve as a guide for producing materials with desired properties from protein-based materials, particularly in textile, high performance composite and catalyst industries.

Senoz, Erman

298

Morphological characterization of furfuraldehyde resins adsorbents  

Energy Technology Data Exchange (ETDEWEB)

Sugar cane is one of the most traditional plantation cultivated crops in large areas in Brazil. The State University of the North of Rio de Janeiro, UENF, is currently engaged in a program aimed to exploit the potentialities of sugar cane industry as a self sustained non-polluting enterprise. One of the projects being carried out at the UENF is the transformation of sugar cane bagasse in precursor materials for the industry of furan derivatives such as the furfuraldehyde resins obtained by acid catalysis. The possibility of employing acid catalyzed furfuraldehyde resins as selective adsorbents has arisen during a comprehensive study of physical-chemical adsorption properties of these materials. The morphology of these resins depend on the synthesis method. Scanning Electron Microscopic studies of these materials which were synthesized, in bulk (FH-M) and solution (FH-D), showed differences in surface density and particle size. Using mercury porosimeter techniques and BET adsorption methods, it was found different pore size distributions and a decrement in surface area when solvent was employed in the synthesis process. By thermogravimetric analysis it was found similar weight losses (6%) of water adsorption and a small differences in thermal stabilities.

Sanchez, R.; Monteiro, S.N. [State Univ. of the North of Rio de Janeiro (Brazil); D`Almeida, J.R. [Rio de Janeiro-Catholic Univ. (Brazil)

1996-12-31

299

Neutron reflectivity study of adsorbed diblock copolymers  

International Nuclear Information System (INIS)

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

1994-01-01

300

Imaging the dynamics of individually adsorbed molecules.  

Science.gov (United States)

Although noise is observed in many experiments, it is rarely used as a source of information. However, valuable information can be extracted from noisy signals. The motion of particles on a surface induced, for example, by thermal activation or by the interaction with the tip of a scanning tunnelling microscope may lead to fluctuations or switching of the tunnelling current. The analysis of these processes gives insight into dynamics on a single atomic or molecular level. Unfortunately, scanning tunnelling microscopy (STM) is not a useful tool to study dynamics in detail, as it is an intrinsically slow technique. Here, we show that this problem can be solved by providing a full real-time characterization of random telegraph noise in the current signal. The hopping rate, the noise amplitude and the relative occupation of the involved states are measured as a function of the tunnelling parameters, providing spatially resolved maps. In contrast to standard STM, our technique gives access to transiently populated states revealing an electron-driven hindered rotation between the equilibrium and two metastable positions of an individually adsorbed molecule. The new approach yields a complete characterization of copper phthalocyanine molecules on Cu(111), ranging from dynamical processes on surfaces to the underlying electronic structure on the single-molecule level. PMID:23263642

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

2012-12-23

 
 
 
 
301

Interaction of PC-3 cells with fibronectin adsorbed on sulfonated polystyrene surfaces  

Directory of Open Access Journals (Sweden)

Full Text Available The ability of cancer cells to invade neighboring tissues is crucial for cell dissemination and tumor metastasis. It is generally assumed that cell adhesion to extracellular matrix proteins is an important stage of cancer progression. Hence, adhesion of cancer cells under in vitro conditions to proteins adsorbed on a substratum surface has been studied to provide a better understanding of cell-protein interaction mechanisms. A protein, adsorbed in an appropriate conformation on a substratum surface, creates a biologically active layer that regulates such cell functions as adhesion, spreading, proliferation and migration. In our study, we examined the interaction of PC-3 cells under in vitro conditions with fibronectin adsorbed on sulfonated polystyrene surfaces of a defined chemical composition and topography. We investigated cell adhesion to fibronectin and cell spreading. Using automatic, sequential microscopic image registration, we are the first to present observations of the dynamics of PC-3 cell spreading and the cell shape during this process. Our results show that cell adhesion and the shape of spreading cells strongly depend on the time interaction with fibronectin. The analysis of images of cytoskeletal protein distribution in the cell region near the cell-substratum interface revealed that induction of a signal cascade took place, which led to the reorganization of the cytoskeletal proteins and the activation of focal adhesion kinase (FAK). (Folia Histochemica et Cytobiologica 2011; Vol. 49, No. 4, pp. 706–718)

Anna Stachurska; Hanna M. Kowalczy?ska

2012-01-01

302

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

Science.gov (United States)

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

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

2013-01-01

303

Improved production of teicoplanin using adsorbent resin in fermentations.  

UK PubMed Central (United Kingdom)

AIMS: To use adsorbent resins in fermentations to eliminate toxic effects on growth, reduce feedback repression of production and assist in recovery of teicoplanin. METHODS AND RESULTS: An adsorbent resin was added to the culture broth for the adsorption of teicoplanin. Amberlite XAD-16, Diaion HP-20, charcoal and silica gel were investigated as adsorbent resins. The adsorbed teicoplanin was extracted from the resin by 80% methanol after fermentation. Antibiotic activity was quantified by the disc-agar diffusion assay against Bacillus substilis, and qualitative evaluations were based on HPLC using YMC-Pack ODS-A column. Diaion HP-20 was the most effective adsorbent resin when added at a concentration of 5% (w/v) in the inoculation stage. CONCLUSIONS: Addition of Diaion HP-20 in fermentations eliminated toxic effects on growth and reduced feedback repression of teicoplanin by adsorption. There was a 4.2-fold increase in the quantities of teicoplanin. Addition of adsorbent assisted in the recovery of teicoplanin by reducing the recovery steps. SIGNIFICANCE AND IMPACT OF THE STUDY: The results of this study provide useful information for the production of teicoplanin, a glycopeptide antibiotic produced by Actinoplanes teicomyceticus. Addition of adsorbent in fermentation increased productivity of teicoplanin by more than five times.

Lee JC; Park HR; Park DJ; Lee HB; Kim YB; Kim CJ

2003-01-01

304

Carbon dioxide pressure swing adsorption process using modified alumina adsorbents  

Energy Technology Data Exchange (ETDEWEB)

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

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

1999-01-01

305

UHV cell for Raman studies of gases adsorbed on metals  

Energy Technology Data Exchange (ETDEWEB)

We describe a UHV Raman cell for the study by laser Raman spectroscopy of gases adsorbed at low coverages on smooth metal surfaces. Provision is made for three samples, and the sample temperature is controlled from 100 to 800 K. The cell also contains a residual gas analyzer, an argon-ion sputter gun for cleaning the samples, and ports for observation of right-angle and oblique Raman scattering. Displayed are Raman spectra of CO on Ni(111) adsorbed from the chamber residual gases and Raman spectra of CH/sub 3/COCH/sub 3/ adsorbed on the same single crystal at 10 L exposure.

Arunkumar, K.A.; Marzouk, H.A.; Bradley, E.B.

1984-06-01

306

UHV cell for Raman studies of gases adsorbed on metals  

International Nuclear Information System (INIS)

[en] We describe a UHV Raman cell for the study by laser Raman spectroscopy of gases adsorbed at low coverages on smooth metal surfaces. Provision is made for three samples, and the sample temperature is controlled from 100 to 800 K. The cell also contains a residual gas analyzer, an argon-ion sputter gun for cleaning the samples, and ports for observation of right-angle and oblique Raman scattering. Displayed are Raman spectra of CO on Ni(111) adsorbed from the chamber residual gases and Raman spectra of CH3COCH3 adsorbed on the same single crystal at 10 L exposure

1984-01-01

307

Investigation of polymer brushes and adsorbed layers under shear  

International Nuclear Information System (INIS)

Neutron reflectometry was used to investigate the density profiles of polymer brushes and an adsorbed polymer layer under shear. The brushes consisted of end-functionalized deuterated polystyrene. The adsorbed polymer was a random copolymer of deuterated styrene and 4-vinylpyridine. The brush and the adsorbed layer were sheared by the flowing of solvents over the polymer, with a maximum shear rate of 104s-1. Density profiles of the brush and the layer were determined before, during and after shear. The shear had no observable effect on the polymer profiles in any of the experiments. We discuss these results in the context of other experiments and a recent theory. (orig.).

1997-01-01

308

PHYSICAL CHARACTERIZATION AND DESULFURIZATION OF BIOBRIQUETTE USING CALCIUM-BASED ADSORBENT  

Directory of Open Access Journals (Sweden)

Full Text Available Combustion of coal and co-combustion of their co-fuel contribute to gas emissions. Among the gas emissions are SOx, NOx, CO and CO2. Introduction of calcium based adsorbent is addressed to absorb SO2 that release to the atmosphere during the combustion process. Objective of the research is at first to observe the physical characteristics of biobriquettes as a function of briquette compositions (coal to palm kernel shell ratios) and Ca/S ratios (Ca in adsorbent and S in briquette) using a natural adsorbent (shellfish waste). The second objective is to investigate desulfurizationcharacteristics as a function of Ca/S ratios and desulfurization temperatures at coal to palm kernel shell ratio of 90:10 (wt %). Ratios of coal to palm kernel shell in this study are 90:10, 80:20, 70:30, 60:40 and 50:50; and Ca/S ratios are 1:1, 1.25:1, 1.5:1, 1.75:1 and 2:1. Binding agent used is the mixture of Jatropha curcas seeds and starch as much as 10% (wt). It was found that introducing the palm kernel shell and adsorbents in the coal briquette affect the water resistant and compressive strength. The highest water resistance and compressive strength were 5,165 second and 34 kg/cm2, respectively. The lowest SO2 level found in this study was 1 ppm for all Ca/S ratios, except for 1:1.

Mahidin; Asri Gani; Khairil

2011-01-01

309

Photoreactions of organic compounds adsorbed on zeolites  

International Nuclear Information System (INIS)

The internal spaces of zeolites can have effects on organic photochemical reactions. ?-Irradiation of zeolites enhances the low-temperature catalytic activity of alkyl aromatic compounds through their Broensted acid sites. The irradiated solids have long-lived excited states with lifetimes as long as years at room temperature. The reactions on the zeolites occur in the channels or cavities of those solids. The mechanism of these reactions involves the dealkylation of benzenium ion to a chemisorbed carbonium ion followed by transalkylation or isomerization. The intermolecular transalkylation reactions are prevented because their transition states would be too large to be accommodated in the cavities of zeolites. The reactivity is a function of the number of acid sites in the zeolite and increases as the degree of substitution of the alkyl group increases. The channel size of the zeolites controls the ratio of the product isomers. It was found that ?-irradiated H-mordenite treated with methylene chloride methylated iso-propylbenzene. When iso-propylbenzene containing iso-propylbenzenehydroperoxide was the reactant the yields of non-oxygenated products were enhanced while oxygenated products were also formed. The photolysis at 300 nm of trans-stilbene adsorbed on zeolites has also been studied. Isomerization to cis-stilbene, cyclo-addition to dihydrophenanthrene followed by oxidation to phenanthrene, and dimerization, all occur. The cis-trans photo-isomerization reaction of trans-stilbene on the zeolite is not favorable, because the sizes of the zeolite cavities and channels make the smaller trans-stilbene more stable than cis-stilbene. However, zeolites can catalyze the cycloaddition of cis-stilbene to dihydrophenanthrene which is subsequently oxidized to phenanthrene.

1990-01-01

310

Adsorption of remazol brilliant blue on an orange peel adsorbent  

Scientific Electronic Library Online (English)

Full Text Available Abstract in portuguese A novel orange peel adsorbent developed from an agricultural waste material was characterised and utilised for the removal of Remazol Brilliant Blue from an artificial textile-dye effluent. The adsorption thermodynamics of this dye-adsorbent pair was studied in a series of equilibrium experiments. The time to reach equilibrium was 15 h for the concentration range of 30 mg L-1 to 250 mg L-1. The adsorption capacity decreased with increasing temperature, from 9.7 mg L-1 at (more) 20 ºC to 5.0 mg L-1 at 60 ºC. Both the Langmuir and Freundlich isotherm models fitted the adsorption data quite reasonably. The thermodynamic analysis of dye adsorption onto the orange peel adsorbent indicated its endothermic and spontaneous nature. Thus, the application of orange peel adsorbent for the removal of dye from a synthetic textile effluent was successfully demonstrated.

Mafra, M. R.; Igarashi-Mafra, L.; Zuim, D. R.; Vasques, É. C.; Ferreira, M. A.

2013-09-01

311

Specific channels for electron energy dissipation in the adsorbed system.  

UK PubMed Central (United Kingdom)

Elastic electron scattering by the adsorbate covered Pt(100) single crystal surface and density of states (DOS) calculations highlight two peculiar channels for the primary electron energy consumption via the conventional threshold core level excitation coupled with particular electron transitions. The first channel affects the substrate atoms and implies Pt DOS shake-off and shake-up transitions and multiple plasmon excitations; the second one includes shake-off processes in the adsorbed layer and enables the valence state structure of the adsorbed species. The mechanism of electron transitions assumes that one-dimensional DOS at the vacuum level, in addition to vacant DOS at the Fermi level, is an active spot for allocation of excited electrons. The observed phenomena are supposed to be the general regularity of electron-solid interaction and a useful tool for fingerprinting the adsorbed layer at molecular level.

Cholach A; Tapilin V

2013-03-01

312

Re-generating method and device for tritium water adsorbent  

International Nuclear Information System (INIS)

Tritium is adsorbed in the form of tritium water to adsorbents used for a convenient tritium removing device. Accordingly, tritium water can be removed as tritium vapor by keeping the used adsorbents in an electric furnace at a high temperature for a certain period of time. Then, upon recovering the vapors, they are at first condensated in a first water collecting device not using a cooling device. Then, uncondensated tritium vapors are condensated in a second water collecting device having a cooling device. By using the 2-step water collecting devices, nearly about 100% of tritium vapors can be collected. Thus, the radioactive wastes can be de-volume into tritium water of less volume, and the adsorbents can be regenerated. (T.M.).

1988-10-11

313

Aminopolycarboxylic acid functionalized adsorbents for heavy metals removal from water.  

UK PubMed Central (United Kingdom)

Due to the excellent chelating properties of aminopolycarboxylic acid (APCAs), they can be used for the removal of metals from contaminated waters. This paper reviews the research results obtained for both commercial and self-prepared adsorbents functionalized with four most common APCAs: iminodiacetic acid (IDA), nitrilotriacetic acid (NTA), ethylenediaminetetraacetic acid (EDTA), and diethylenetriaminepentaacetic acid (DTPA). The structural characteristics and unique metal binding properties of these chelating adsorbents are presented. The theory of the adsorption phenomena is discussed based on the kinetics of adsorption, equilibrium adsorption isotherm models, and thermodynamic models. The most important applications of APCA-functionalized adsorbents are also described. APCA-functionalized adsorbents are found to be highly promising materials for metal removal from contaminated waters.

Repo E; Warcho? JK; Bhatnagar A; Mudhoo A; Sillanpää M

2013-09-01

314

TESTING OF CARBONACEOUS ADSORBENTS FOR REMOVAL OF POLLUTANTS FROM WATER  

Directory of Open Access Journals (Sweden)

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

RAISA NASTAS; MARINA TCACI; TATIANA GOREACIOC; V.RUSU; T.LUPASCU

2012-01-01

315

Atomic scale friction of molecular adsorbates during diffusion  

CERN Multimedia

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

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

2013-01-01

316

Adsorbents for uranium prepared from maleic anhydride polymers  

International Nuclear Information System (INIS)

Adsorbents for uranium were prepared from crosslinked maleic anhydride polymers and alkaline solution, hydroxylamine, 2-aminopyridine, 3-aminopyridine, (2-pyridylmethylene) diazane or [1-(2-pyridyl) ethylidene] diazane. Maleic acid polymer (I) showed good adsorptive ability for uranium in acidic uranium enriched seawater. In seawater, adsorbents prepared from maleic anhydride polymer and hydrazones (VI, VII) showed the adsorptive ability of 4 ?g/g in 10 days. (author)

1985-01-01

317

???????????? ????????? ??????????? ? ???????? ??????? ?????????????? USING OF NATURAL ADSORBENTS IN PROCESSES OF PETROLEUM PRODUCTS’ CLEARING ????????????? ????????? ??????????? ? ????????? ??????? ??????????????  

Directory of Open Access Journals (Sweden)

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

Sergey V. Ivanov; Antonina D. Kustovska; Sergey D. Nedaiborshch; ?lena V. Kharchenko

2008-01-01

318

Distribution of adsorbed molecules in electronic nose sensors  

DEFF Research Database (Denmark)

Neutron reflectivity measurements of thin films of electropolymerised poly(pyrrole) show that swelling of these insoluble polymers does occur following vapour adsorption. The variation in swelling found for different vapours is correlated with corresponding changes in polymer conductivity and mass of adsorbed vapour. This correlation suggests that hydrophobic and hydrophilic vapour species adsorb into regions of the membrane with different solvating environments (C) 2000 Elsevier Science B.V. All rights reserved.

Swann, M.J.; Glidle, A.

2000-01-01

319

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

International Nuclear Information System (INIS)

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

1989-01-01

320

New method for affinity adsorbent screening using gold colloids.  

UK PubMed Central (United Kingdom)

A rapid, effective method for the screening of adsorbent ligands based on the unique optical properties of gold colloid has been developed. Different interactions between adsorbate and ligands induce different states of aggregation of the gold colloid, and the associated distinct color changes of the colloid have been utilized to estimate the affinity of the ligands toward the adsorbate. In this work, phosphorylated peptide CGGFGGpSG was appended to a gold colloid to obtain the adsorbate-modified gold colloid (CG8-AuNPs). Candidate ligands Dpa-Zn(2+), DMAPAA, and AAn were copolymerized with acrylamide to form linear polymers and cross-linked CG8-AuNPs to induce aggregation. Screening of the candidate ligands revealed that Dpa-Zn(2+) showed the highest affinity among those tested, inducing a color change of the gold colloid at a concentration of 10 ?M, which is much lower than those of ligands DMAPAA (40 ?M) and AAn (almost no color change could be observed). Subsequent statistical adsorption experiments confirmed these screening results, with the adsorbent A-AAm-Dpa-Zn(2+) showing the highest adsorption capacity (426 mg/g) for CG-8, almost twice that of adsorbent A-AAm-DMAPAA. This reported method has low sample consumption, and the screening may be simply monitored by the naked eye.

Wang J; Wang W; Wei Q; Zhang S; Yuan Z

2011-09-01

 
 
 
 
321

Adsorbates effects in H^- - Na/Cu(111) collisions  

Science.gov (United States)

The (111) faces of Cu, Ag and Au present a band gap that extends just below the vacuum level at the ? gpoint [1]. The effect is to forbid electrons with energies in a certain range to be transferred into the metal along the surface normal. Thus, the presence of a band gap should dramatically influence various experiments in ion-surface collisions involving electron capture or loss. In recent years, this topic received a great interest [2 -- 4]. Adsorbates deposition makes the electron dynamics at such surfaces to be even more complex. We analyze some interesting adsorbates effects: (1) projectile energy levels and widths are strongly perturbed when this approaches close to an adsorbate atom; (2) scattering by adsorbates may be used to laterally confine surface state electrons; (3) adsorbates may enhance the band gap effect; (4) adsorbates tend to couple the surface states to the bulk states. Results for the H^- projectile interacting with a Na/Cu(111) surface are reported. [1] E.V. Chulkov, V.M. Silkin and P.M. Echenique 1999 Surf. Sci. 437, 330. [2] A.G. Borisov, A.K. Kazansky and J.P. Gauyacq 1999 Phys. Rev. B. 59, 10935. [3] H.S. Chakraborty, T. Niederhausen and U. Thumm 2004 Phys. Rev. A. 70, 052903. [4] B. Bahrim, B. Makarenko and J.W. Rabalais 2005 Surface Sci. 594, 62.

Bahrim, Bogdana; Yu, Song

2008-03-01

322

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

Directory of Open Access Journals (Sweden)

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

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

2013-01-01

323

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

UK PubMed Central (United Kingdom)

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

Jahangiri M; Adl J; Shahtaheri SJ; Rashidi A; Ghorbanali A; Kakooe H; Forushani AR; Ganjali MR

2013-01-01

324

Preparation of a New Adsorbent from Activated Carbon and Carbon Nanofiber (AC/CNF) for Manufacturing Organic-Vacbpour Respirator Cartridge  

Directory of Open Access Journals (Sweden)

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

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

2013-01-01

325

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

Science.gov (United States)

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

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

2013-01-26

326

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

DEFF Research Database (Denmark)

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

Lausche, Adam C.; Medford, Andrew J.

2013-01-01

327

Fracture resistance of a TiB/sub 2/ particle/SiC matrix composite at elevated temperature  

Energy Technology Data Exchange (ETDEWEB)

The fracture resistance of a commercial TiB/sub 2/ particle/SiC matrix composite was evaluated at temperatures ranging from 20 to 1400 C. A laser interferometric strain gauge (LiSG) was used to continuously monitor the crack mouth opening displacement (CMOD) of the chevron-notched and straight-notched, three-point bend specimens used. Crack growth resistance curves (R-curves) were determined from the load versus displacement curves and displacement calibrations. Fracture toughness, work-of-fracture, and R-curve levels were found to decrease with increasing temperature. Microstructure, fracture surface, and oxidation coat were examined to explain the fracture behavior. 23 references.

Jenkins, M.G.; Salem, J.A.; Seshadri, S.G.

1989-01-01

328

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

Directory of Open Access Journals (Sweden)

Full Text Available Zr(OH)4 particle can be formed and negatively charged in alkaline solution with K2ZrF6 addition. Based on this mechanism, Zr-containing ceramic coatings were fabricated on LY12 aluminum alloy by microarc oxidation (MAO) using K2ZrF6 as a special additive in Na2SiO3-KOH base electrolyte. The modulation effects of K2ZrF6 addition on micro-microstructure, element distribution and phase composition were analyzed by SEM, EDS and XRD, respectively. Heat resistance of MAO coatings formed on LY12 aluminum alloy in different electrolyte was investigated. The results show that the K2ZrF6 addition can increase the micro-arc oxidation rate and significantly alter the structure of MAO coatings. Both the top surface and inner surface of MAO coatings fabricated in Zr-containing electrolyte become relatively smooth. Compared with the coating formed in Zr-free electrolyte, a large amount of Zr element is found in the coating formed in electrolyte with K2ZrF6 addition. Two main phases, ?-Al2O3 and ?-Al2O3, are contained in Zr-free coating. In contrast, more amorphous phase is found in Zr-containing coating with reduced amount of crystalline alumina. Experimental results also demonstrate that Zr-containing coating exhibits higher heat resistance.

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

2010-01-01

329

Clinical long-term outcome after implantation of titanium nitride-oxide coated stents compared with paclitaxel- or sirolimus-eluting stents: propensity-score matched analysis.  

UK PubMed Central (United Kingdom)

AIMS: We performed a propensity score matched analysis to explore whether TiNOX stents are superior to paclitaxel- (PES) and sirolimus-eluting stents (SES) in routine clinical practice. METHODS AND RESULTS: A total of 1,607 patients undergoing implantation of SES, PES or TiNOX stents were prospectively entered into a stent registry and followed up for three years. Using propensity score matching, we compared clinical outcome among 319 pairs of patients treated with TiNOX stents or SES and 337 pairs of patients treated with TiNOX stents or PES. The primary outcome MACE, a composite of death, myocardial infarction, and target vessel revascularisation occurred in 20% of patients with TiNOX stents, 19% of patients with SES and 23% of patients with PES at 3-years. The hazard ratio was 1.00 comparing TiNOX stents with SES (95% CI 0.69-1.45, p=1.00), and 0.95 comparing TiNOX stents with PES (95% CI 0.66-1.36, p=0.78). CONCLUSION: We did not find evidence to suggest superiority of TiNOX stents over SES or PES. In view of similar clinical outcomes, but with the reduced duration of dual antiplatelet therapy used with the TiNOX stent, we suggest that TiNOX stents may be an alternative to drug-eluting stents in patients unsuitable for long-term dual antiplatelet therapy.

Limacher A; Räber L; Laube E; Lauterburg A; Lötscher S; Hess N; Moschovitis A; Baldinger SH; Wenaweser P; Meier B; Hess OM; Jüni P

2012-01-01

330

Irradiation of alkyl siloxanes in the adsorbed state. Part 3. The irradiation chemistry of hexamethyldisiloxane adsorbed onto silica. [Gamma Radiation  

Energy Technology Data Exchange (ETDEWEB)

Enhanced production of hydrogen, methane, and ethane from the ..gamma..-irradiation of hexamethyldisiloxane (MM) adsorbed onto silica compared to that from liquid MM results from energy transfer from the solid to the adsorbed layer. Chemical reactions with the surface are shown by deuterated products from the irradiation of MM on a deuterated silica and from extensive chemical cross-linking to the surface. These reactions predominate in the first monolayer of coverage.

Maeng, K.; Brown, G.R.; Trudel, G.J.; St-Pierre, L.E. (McGill Univ., Montreal, Quebec (Canada). Dept. of Chemistry)

1983-04-01

331

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

Energy Technology Data Exchange (ETDEWEB)

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

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

2012-07-15

332

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

International Nuclear Information System (INIS)

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

2012-01-01

333

Tobacco waste/industrial sludge based desulfurization adsorbents: effect of phase interactions during pyrolysis on surface activity.  

UK PubMed Central (United Kingdom)

Industrial waste derived adsorbents were obtained by pyrolysis of tobacco waste with either metal sludge or waste oil sludge from a shipyard. The materials were used as media to remove hydrogen sulfide at room temperature in the presence of moisture. The initial and exhausted adsorbents after the breakthrough tests were characterized using sorption of nitrogen, thermal analysis, XRD, elemental analysis, and surface pH measurements. It was found that mixing tobacco and industrial sludges results in a strong synergy, enhancing the catalytic properties of adsorbents. This synergy is observed in both surface chemistry and porosity. During pyrolysis, new mineral phases are formed as a result of solid-state reactions between the components of the sludges. They are highly dispersed on the surface of mesopores. A high volume of these pores is a result of activation of the carbon phase in the composite by alkaline earth metals and also by the release of water from the decomposition of an inorganic phase that is in the predominant quantity. A high temperature of pyrolysis is beneficial for the adsorbents due to the enhanced activation of the carbonaceous phase and the chemical stabilization of the inorganic phase. Samples obtained at low temperatures are sensitive to water, which deactivates their catalytic centers.

Seredych M; Bandosz TJ

2007-05-01

334

Tobacco waste/industrial sludge based desulfurization adsorbents: effect of phase interactions during pyrolysis on surface activity.  

Science.gov (United States)

Industrial waste derived adsorbents were obtained by pyrolysis of tobacco waste with either metal sludge or waste oil sludge from a shipyard. The materials were used as media to remove hydrogen sulfide at room temperature in the presence of moisture. The initial and exhausted adsorbents after the breakthrough tests were characterized using sorption of nitrogen, thermal analysis, XRD, elemental analysis, and surface pH measurements. It was found that mixing tobacco and industrial sludges results in a strong synergy, enhancing the catalytic properties of adsorbents. This synergy is observed in both surface chemistry and porosity. During pyrolysis, new mineral phases are formed as a result of solid-state reactions between the components of the sludges. They are highly dispersed on the surface of mesopores. A high volume of these pores is a result of activation of the carbon phase in the composite by alkaline earth metals and also by the release of water from the decomposition of an inorganic phase that is in the predominant quantity. A high temperature of pyrolysis is beneficial for the adsorbents due to the enhanced activation of the carbonaceous phase and the chemical stabilization of the inorganic phase. Samples obtained at low temperatures are sensitive to water, which deactivates their catalytic centers. PMID:17547202

Seredych, Mykola; Bandosz, Teresa J

2007-05-15

335

Lineshape broadening in surface diffusion of interacting adsorbates with quasi-elastic He atom scattering  

CERN Multimedia

The experimental lineshape broadening observed in adsorbate diffusion on metal surfaces with increasing coverage is usually assigned to the nature of the adsorbate-adsorbate interaction. Far from this idea, here we show that this broadening is easily understandable in terms of a fully stochastic model just considering two noise sources: (i) a Gaussian white noise accounting for the friction led by the surface on the adsorbates, and (ii) a shot noise replacing the physical adsorbate-adsorbate interaction potential because any trace of the latter is wiped out in the statistical limit (a large number of collisions for relatively long timescales). It is seen that the adsorbate-substrate interaction plays a relevant role in the observance of broadening regardless the type of adsorbate-adsorbate interaction potential assumed. Furthermore, contrary to what could be expected, for relatively weak adsorbate-substrate interactions the opposite effect is predicted: lineshapes get narrower as coverage increases.

Martinez-Casado, R; Sanz, A S; Miret-Artés, S

2007-01-01

336

Adsorbed serum proteins responsible for surface dependent human macrophage behavior.  

UK PubMed Central (United Kingdom)

Substrate specific cellular responses are the result of a complex biological system that includes protein adsorption, receptor-ligand binding, and signal transduction. This investigation attempted to identify specific proteins adsorbed from human serum that may be responsible for the previously reported in vitro surface dependent behavior of human macrophages and foreign body giant cells (FBGCs). The adsorption of human albumin, alpha(2)-macroglobulin, complement factor 3b, fibronectin, IgG, thrombospondin, vitronectin (VN), and von Willebrand factor (vWF) from a 25% serum solution was quantified with (125)I-labeled protein. Adsorption substrates included clean glass, alkyl-silane modified glass, amino-silane modified glass, poly(ethylene oxide) (PEO)-coupled glass, and the reference biomaterials poly(etherurethane urea), Silastic(R), and poly(tetrafluoroethylene) (PTFE). Following quantification of 2-h adsorption, surfaces were treated with sodium dodecyl sulfate (SDS) and the level of adsorbed proteins remaining was quantified. The pre- and post-SDS adsorption were both compared to previously reported surface dependent in vitro macrophage and FBGC behavior on the same surfaces; however, no correlations could be made. Adsorption strength, defined as the percentage of initially adsorbed protein that remained adsorbed after SDS treatment, correlated well with previously reported in vitro cellular behavior indicating that adsorbed vWF, IgG, and VN may be involved in the modulation of adherent macrophage and FBGC behavior. Those surfaces that strongly adsorbed vWF also inhibited long-term macrophage adhesion, while those surfaces that strongly adsorbed IgG promoted long-term macrophage adhesion. In addition, the highest levels of FBGC formation had been observed only on those surfaces that strongly adsorbed VN. Subsequent human monocyte cultures on protein preadsorbed substrates confirmed the inhibitory effect of adsorbed vWF and the promoting effect of IgG on longterm macrophage adhesion as predicted by adsorption strength correlations. However, preadsorbed VN was not observed to modulate FBGC formation, which is in contrast to the conclusions of the adsorption correlations.

Jenney CR; Anderson JM

2000-03-01

337

Regeneration of thermally polymerized frying oils with adsorbents  

UK PubMed Central (United Kingdom)

Two thermally polymerized palm oils used continuously for deep-fat frying of legume-based snacks for 30 and 36h were treated with various adsorbents as such and in binary and quaternary blends, in an attempt to regenerate them. Activated charcoal powder (ACH), aluminum oxide (ALO), aluminum hydroxide (ALH), activated clay (ACL), celite (CE) and silica gel (SG), activated carbon (ACA), frypowder (FP), britesorb (BR) and magnesol (MA) were evaluated for their efficacy in regenerating the oils in terms of their effects on physicochemical parameters such as free fatty acids (FFA), total polar materials (TPM), p-anisidine value (p-AV), conjugated dienes, viscosity and colour. Binary and quaternary adsorbent treatments were better than single adsorbents in improving the overall quality of the oils studied. The efficacy of the best adsorbent blend was further evaluated in a highly polymerized cottonseed oil collected from a local eatery. Use of such adsorbents is recommended for small processing units in the unorganized sector, where such polymerized oil is generally discarded.

Bhattacharya AtanuB; Sajilata MG; Tiwari SudhaR; Singhal RekhaS

2008-10-01

338

Structure and Reactivity of Adsorbed Fibronectin Films on Mica  

Science.gov (United States)

Understanding the interactions of adsorbed fibronectin (Fn) with other biomolecules is important for many biomedical applications. Fn is found in almost all body fluids, in the extracellular matrix, and plays a fundamental role in many biological processes. This study found that the structure (conformation, orientation) and reactivity of Fn adsorbed onto mica is dependent on the Fn surface concentration. Atomic force microscopy and x-ray photoelectron spectroscopy were used to determine the surface coverage of adsorbed Fn from isolated molecules at low surface coverage to full monolayers at high surface coverage. Both methods showed that the thickness of Fn film continued to increase after the mica surface was completely covered, consistent with Fn adsorbed in a more upright conformation at the highest surface-Fn concentrations. Time-of-flight secondary ion mass spectrometry showed that relative intensities of both sulfur-containing (cystine, methionine) and hydrophobic (glycine, leucine/isoleucine) amino acids varied with changing Fn surface coverage, indicating that the conformation of adsorbed Fn depended on surface coverage. Single-molecule force spectroscopy with collagen-related peptides immobilized onto the atomic force microscope tip showed that the specific interaction force between the peptide and Fn increases with increasing Fn surface coverage.

Hull, James R.; Tamura, Glen S.; Castner, David G.

2007-01-01

339

Toward a detailed characterization of oil adsorbates as "solid liquids".  

Science.gov (United States)

Solid lipid formulation systems are used to overcome oral bioavailability problems of poorly water-soluble drugs. One promising process is the conversion of a liquid lipid system in a free flowing powder by use of adsorbing excipients. The aim of this study was the detailed characterization of solid-liquid interactions in oil adsorbed to Fujicalin and Neusilin which were manufactured by means of dual asymmetric centrifugation or conventional mortar/pestle blending. The adsorption strength of the excipients was investigated by Benchtop-NMR and ESR spectroscopy revealing the highest adsorption power for the Neusilin products. The adsorbate production methods as well as the storage of the excipients impact their adsorption properties. Environmental scanning electron microscopy (ESEM) and confocal laser scanning microscopy (CLSM) show that dual asymmetric centrifugation leads to a smoothing of the particle surface, whereas the mortar/pestle blending results in an uneven surface and particle destruction. The oil distribution at the particles is inhomogeneous for both production methods. The micropolarity of the adsorbed oil was investigated by ESR spectroscopy and multispectral fluorescence imaging. The adsorbing process on Neusilin leads to an increased micropolarity of the oil component. The release of the oil component in aqueous media could be verified by Benchtop-NMR and multispectral fluorescence imaging. PMID:23275113

Kutza, Claudia; Metz, Hendrik; Kutza, Johannes; Syrowatka, Frank; Mäder, Karsten

2012-12-27

340

Toward a detailed characterization of oil adsorbates as "solid liquids".  

UK PubMed Central (United Kingdom)

Solid lipid formulation systems are used to overcome oral bioavailability problems of poorly water-soluble drugs. One promising process is the conversion of a liquid lipid system in a free flowing powder by use of adsorbing excipients. The aim of this study was the detailed characterization of solid-liquid interactions in oil adsorbed to Fujicalin and Neusilin which were manufactured by means of dual asymmetric centrifugation or conventional mortar/pestle blending. The adsorption strength of the excipients was investigated by Benchtop-NMR and ESR spectroscopy revealing the highest adsorption power for the Neusilin products. The adsorbate production methods as well as the storage of the excipients impact their adsorption properties. Environmental scanning electron microscopy (ESEM) and confocal laser scanning microscopy (CLSM) show that dual asymmetric centrifugation leads to a smoothing of the particle surface, whereas the mortar/pestle blending results in an uneven surface and particle destruction. The oil distribution at the particles is inhomogeneous for both production methods. The micropolarity of the adsorbed oil was investigated by ESR spectroscopy and multispectral fluorescence imaging. The adsorbing process on Neusilin leads to an increased micropolarity of the oil component. The release of the oil component in aqueous media could be verified by Benchtop-NMR and multispectral fluorescence imaging.

Kutza C; Metz H; Kutza J; Syrowatka F; Mäder K

2013-05-01

 
 
 
 
341

Five-year clinical outcome of titanium-nitride-oxide-coated bioactive stent implantation in a real-world population: a comparison with paclitaxel-eluting stents: the PORI registry.  

UK PubMed Central (United Kingdom)

AIMS: We sought to present the 5-year clinical outcome of the titanium-nitride-oxide-coated bioactive stents (BAS), as compared to paclitaxel-eluting stents (PES), in a real-world patient population. METHODS: From May 2003 to November 2004, we enrolled 405 consecutive patients who underwent percutaneous coronary intervention with either BAS or PES implantation. Patients were prospectively followed up for 5 years. The primary end-point was major adverse cardiac events (MACE) at 5-year follow-up including cardiac death, nonfatal myocardial infarction (MI), or target lesion revascularization. RESULTS: A total of 201 patients received BAS (218 lesions/221 stents) while 204 patients received PES (244 lesions/247 stents). Clinical follow-up for 5 years was completed in all patients. Cumulative MACE at the end of 5-year follow-up occurred in 34 (16.9%) patients in the BAS group, as compared to 53 (26%) in the PES group (OR 1.7, 95% CI 1.1-2.8, P = 0.03). This difference was mainly driven by a lower incidence of MI in the BAS group as compared with the PES group (9.5% vs. 20.6%, OR 2.5, 95% CI 1.4-4.4, P = 0.002). Stent thrombosis occurred in 16 (7.8%) patients in the PES group, while no one suffered stent thrombosis in the BAS group. CONCLUSION: BAS implantation in a real-world patient population achieves an excellent clinical outcome over 5-year follow-up, with a significantly lower incidence of MI, MACE, and stent thrombosis as compared to PES.

Karjalainen PP; Ylitalo A; Airaksinen JK; Nammas W

2011-02-01

342

Ketoimine modified silica as an adsorbent for gas chromatographic analysis of olefins.  

UK PubMed Central (United Kingdom)

New adsorbents for capillary complexation GC have been proposed. The adsorbents contain free ketoimine groups which enable binding copper(II) and chromium(III) chlorides. The adsorbents obtained have been characterised by elemental analysis, differential scanning calorimetry and electron spin resonance. The specific interactions between the adsorbent and adsorbate molecules have been characterised by retention parameters (retention index - I, specific retention volume - Vg, molecular retention index - deltaMe). Attempts were also made at separating mixtures of olefins.

Wawrzyniak R; Wasiak W

2005-12-01

343

Sprayable titanium composition  

Energy Technology Data Exchange (ETDEWEB)

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

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

1980-01-01

344

Surface modification of chromatography adsorbents by low temperature low pressure plasma  

DEFF Research Database (Denmark)

In this study we show how low temperature glow discharge plasma can be used to prepare bi-layered chromatography adsorbents with non-adsorptive exteriors. The commercial strong anion exchange expanded bed chromatography matrix, Q HyperZ, was treated with plasmas in one of two general ways. Using a purpose-designed rotating reactor, plasmas were employed to either: (i) remove anion exchange ligands at or close to the exterior surface of Q HyperZ, and replace them with polar oxygen containing functions (‘plasma etching and oxidation’); or (ii) bury the same surface exposed ligands beneath thin polymer coatings (‘plasma polymerization coating’) using appropriate monomers (vinyl acetate, vinyl pyrrolidone, safrole) and argon as the carrier gas. X-ray photoelectron spectroscopy analysis (first 10 nm depth) of Q HyperZ before and after the various plasma treatments confirmed that substantial changes to the elemental composition of Q HyperZ's exterior had been inflicted in all cases. The atomic percent changes in carbon, nitrogen, oxygen, yttrium and zirconium observed after being exposed to air plasma etching were entirely consistent with: the removal of pendant Q (trimethylammonium) functions; increased exposure of the underlying yttrium-stabilised zirconia shell; and introduction of hydroxyl and carbonyl functions. Following plasma polymerization treatments (with all three monomers tested), the increased atomic percent levels of carbon and parallel drops in nitrogen, yttrium and zirconium provided clear evidence that thin polymer coats had been created at the exteriors of Q HyperZ adsorbent particles. No changes in adsorbent size and surface morphology, nor any evidence of plasma-induced damage could be discerned from scanning electron micrographs, light micrographs and measurements of particle size distributions following 3 h exposure to air (220 V; 35.8 W L?1) or ‘vinyl acetate/argon’ (170 V; 16.5 W L?1) plasmas. Losses in bulk chloride exchange capacity before and after exposure to plasmas enabled effective modification depths within hydrated Q HyperZ adsorbent particles to be calculated as 0.2–1.2 ?m, depending on the conditions applied. The depth of plasma induced alteration was strongly influenced by the power input and size of the treated batch, i.e. dropping the power or increasing the batch size resulted in reduced plasma penetration and therefore shallower modification. The selectivity of ‘surface vs. core’ modification imparted to Q HyperZ by the various plasma treatments was evaluated in static and dynamic binding studies employing appropriate probes, i.e. plasmid DNA, sonicated calf thymus DNA and bovine serum albumin. In static binding studies performed with adsorbents that had been exposed to plasmas at the 5 g scale (25 g L?1 of plasma reactor), the highest ‘surface/core’ modification selectivity was observed for Q HyperZ that had been subjected to 3 h of air plasma etching at 220 V (35.8 W L?1). This treatment removed 53% of ‘surface’ DNA binding at the expense of a 9.3% loss in ‘core’ protein binding. Even more impressive results were obtained in dynamic expanded bed adsorption studies conducted with Q HyperZ adsorbents that had been treated with air (220 V, 3 h) and ‘vinyl acetate/argon’ (170 V, 3 h) plasmas at 10.5 g scale (52.5 g L?1 of plasma reactor). Following both plasma treatments: the 10% breakthrough capacities of the modified Q HyperZ adsorbents towards ‘surface’ binding DNA probes dropped very significantly (30–85%); the DNA induced inter-particle cross-linking and contraction of expanded beds observed during application of sonicated DNA on native Q HyperZ was completely eradicated; but the ‘core’ protein binding performance remained unchanged cf. that of the native Q HyperZ starting material.

Arpanaei, Ayyoob; Winther-Jensen, BjØrn

2010-01-01

345

High-performances carbonaceous adsorbents for hydrogen storage  

Science.gov (United States)

Activated carbons (ACs) with controlled microporosity have been prepared and their H2 storage performances have been tested in a gravimetric device. Such adsorbents are natural Chinese anthracites chemically activated with alkaline hydroxides, NaOH or KOH. Outstanding total storage capacities of hydrogen, as high as 6.6wt.% equivalent to excess capacity of 6.2 wt.%, have been obtained at 4MPa for some of these adsorbents. These values of hydrogen adsorption are among the best, if not the highest, ever published so far in the open literature. They are well above those of some commercial materials, e.g. Maxsorb-3, considered as a reference of high-performance adsorbent for hydrogen adsorption. Such exceptional storage capacities may be ascribed to a higher volume of micropores (< 2nm).

Zhao, Weigang; Fierro, Vanessa; Aylon, E.; Izquierdo, M. T.; Celzard, Alain

2013-03-01

346

Ultraviolet photoemission studies of methanol adsorbed on Ru(110)  

International Nuclear Information System (INIS)

[en] Methanol (CH3OH) adsorbed on Ru(110) has been studied under UHV conditions by angle-integrated ultraviolet photoemission (UPS) as part of a search for surface complexes related to intermediates present during the methanation reaction on Ru. For low exposures at 80 K, the UPS spectra indicate that the methanol chemisorbs non-dissociatively. In the initial layer, the work function drops linearly with exposure while the orbitals of adsorbed methanol remain fixed in binding energy relative to the Ru Fermi level. The relative spacings of the orbitals suggest that bonding to the substrate occurs via oxygen-derived orbitals. Of the two major desorption products, H2 and CO, hydrogen leaves the surface at lower temperatures. Upon heating the adsorbed methanol, the UPS spectra indicate that methanol decomposes on the surface before significant desorption occurs. (Auth.)

1977-09-16

347

Adsorption of radionuclides from aqueous solutions by inorganic adsorbents  

Energy Technology Data Exchange (ETDEWEB)

Radionuclides such as {sup 137}Cs and {sup 85}Sr were removed from dilute aqueous solutions by means of inorganic adsorbents. MS-13X and chabazite. Adsorption data of radionuclides on the inorganic adsorbents were satisfactorily correlated by the Dubinin-Astakov (DA) equation. Gaussian-type distributions of adsorption energies were obtained from the parameters of the DA equation by applying the condensation approach. A surface diffusion model was applied to estimate the intra-particle mass transfer of radionuclides. The range of surface diffusion coefficients estimated was 3.2 x 10{sup {minus}12} to 3.5 x 10{sup {minus}11} m{sup 2}/s. The adsorption model, which describes the surface diffusion mechanism with the DA equation, satisfactorily simulated the adsorption behavior of radionuclides on zeolites in batch adsorbers.

Kim, B.T.; Lee, H.K. [Korea Atomic Energy Research Inst., Taejon (Korea, Republic of); Moon, H. [Chonnam National Univ., Kwangju (Korea, Republic of); Lee, K.J. [Korea Advanced Inst. of Science and Technology, Taejon (Korea, Republic of)

1995-09-01

348

Adsorbent from Pongamia Pinnata Tree Bark for Zinc Adsorption  

Directory of Open Access Journals (Sweden)

Full Text Available Abstract—In the recent years, Pongamia pinnata trees are widely grown at farms for its seeds utilised for biofuel activities. Due to the easy availability of this tree bark, it is used as a viable adsorbent for removing some heavy metals from aqueous and waste water. In this context, the adsorption of Zinc on prepared adsorbent is very effective. In this study, investigations were made for the adsorption of zinc ions from aqueous and waste water. Batch adsorption studies to determine the optimum conditions of zinc ion removal were conducted to know the influence of experimental conditions such as pH of the solution, metal ion concentration, amount of adsorbent and contact time at room temperature. The results obtained show that the optimum pH range for the zinc removal is 5 – 5.4 and adsorption percent is higher than 95 %. Kinetic study was also made to determine rate constants.

Mamatha M.; Aravinda H. B.; Puttaiah E.T.; Manjappa S.

2013-01-01

349

Ultraviolet and electron radiation induced fragmentation of adsorbed ferrocene  

Energy Technology Data Exchange (ETDEWEB)

From thermal desorption spectroscopy we find that ferrocene, Fe(C{sub 5}H{sub 5}){sub 2}, adsorbs and desorbs associatively on Ag(100). Photoemission results indicate that the initially adsorbed surface species closely resembles that of molecular ferrocene. The shift in photoemission binding energies relative to the gas phase is largely independent of the molecular orbital. We find that ultraviolet light does lead to partial fragmentation of the ferrocene and that the molecular fragments are much more strongly bound to the surface than the associatively adsorbed ferrocene. Since fragmentation occurs only in the presence of incident radiation, selective area deposition from this class of molecules is possible. Using a focused electron beam in a scanning transmission electron microscope, we show that selective area deposition of features with resolution of a few hundred angstroms is readily achieved. {copyright} {ital 1996 American Institute of Physics.}

Welipitiya, D.; Green, A.; Woods, J.P.; Dowben, P.A. [Department of Physics and the Center for Materials Research and Analysis, Behlen Laboratory for Physics, University of Nebraska, Lincoln, Nebraska 68588-0111 (United States); Robertson, B.W.; Byun, D. [Department of Mechanical Engineering and the Center for Materials Research and Analysis, University of Nebraska, Lincoln, Nebraska 68588-0111 (United States); Zhang, J. [Solid State Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831-6030 (United States)

1996-06-01

350

Investigation of polymer brushes and adsorbed layers under shear  

Energy Technology Data Exchange (ETDEWEB)

Neutron reflectometry was used to investigate the density profiles of polymer brushes and an adsorbed polymer layer under shear. The brushes consisted of end-functionalized deuterated polystyrene. The adsorbed polymer was a random copolymer of deuterated styrene and 4-vinylpyridine. The brush and the adsorbed layer were sheared by the flowing of solvents over the polymer, with a maximum shear rate of 10{sup 4}s{sup -1}. Density profiles of the brush and the layer were determined before, during and after shear. The shear had no observable effect on the polymer profiles in any of the experiments. We discuss these results in the context of other experiments and a recent theory. (orig.). 23 refs.

Nguyen, D. [Brookhaven National Lab., Upton, NY (United States); Clarke, C.J.; Eisenberg, A.; Rafailovich, M.H.; Sokolov, J.; Smith, G.S.

1997-10-01

351

High-performances carbonaceous adsorbents for hydrogen storage  

International Nuclear Information System (INIS)

[en] Activated carbons (ACs) with controlled microporosity have been prepared and their H2 storage performances have been tested in a gravimetric device. Such adsorbents are natural Chinese anthracites chemically activated with alkaline hydroxides, NaOH or KOH. Outstanding total storage capacities of hydrogen, as high as 6.6wt.% equivalent to excess capacity of 6.2 wt.%, have been obtained at 4MPa for some of these adsorbents. These values of hydrogen adsorption are among the best, if not the highest, ever published so far in the open literature. They are well above those of some commercial materials, e.g. Maxsorb-3, considered as a reference of high-performance adsorbent for hydrogen adsorption. Such exceptional storage capacities may be ascribed to a higher volume of micropores (

2013-03-14

352

Metal loaded zeolite adsorbents for hydrogen cyanide removal.  

Science.gov (United States)

Metal (Cu, Co, or Zn) loaded ZSM-5 and Y zeolite adsorbents were prepared for the adsorption of hydrogen cyanide (HCN) toxic gas. The results showed that the HCN breakthrough capacity was enhanced significantly when zeolites were loaded with Cu. The physical and chemical properties of the adsorbents that influence the HCN adsorption capacity were analyzed. The maximal HCN breakthrough capacities were about the same for both zeolites at 2.2 mol of HCN/mol of Cu. The Cu2p XPS spectra showed that the possible species present were Cu2O and CuO. The N1s XPS data and FT-IR spectra indicated that CN(-) would be formed in the presence of Cu+/Cu2+ and oxygen gas, and the reaction product could be adsorbed onto Cu/ZSM-5 zeolite more easily than HCN. PMID:23923791

Ning, Ping; Qiu, Juan; Wang, Xueqian; Liu, Wei; Chen, Wei

2013-04-01

353

Phenol removal from wastewater by adsorption on zeolitic composite.  

UK PubMed Central (United Kingdom)

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

Bizerea Spiridon O; Preda E; Botez A; Pitulice L

2013-09-01

354

Phase Diagram of Adsorbate-Induced Row-Type-Alignments  

CERN Multimedia

The phase diagram of adsorbate-induced row-type-alignments, such as missing-row reconstructions induced by adsorbate-atoms on the FCC(110) surface, is calculated by the Blume-Emmery-Griffiths (BEG) model. In the model, we introduce adatom-adatom and dipole-dipole interactions between nearest-neighbor (NN) and next-nearest-neighbor (NNN) rows. The calculation of the temperature versus adatom chemical potential phase diagram is performed using mean-field approximation. It is indicated that when NN and NNN interactions are competitive, there appear either dipole or coverage modulated (incommensurate) phases at high temperatures for wide regime of the interactions.

Kang, M; Kaburagi, M

1999-01-01

355

Removal of uranium by the adsorbents produced from coffee residues  

International Nuclear Information System (INIS)

Large amounts of coffee residues contaminate the environment and reprocessing of them as valuable products such as adsorbents will be a good solution from an environmental and economic point of view. In this study some adsorbents were produced from coffee residues and used for batch removal experiments of uranium from aqueous solutions. The adsorption kinetics was found to follow the Lagergren equation. The adsorption process was described with the Langmuir and Freundlich isotherms. Additionally, the effect of different cations on the adsorption of uranium was studied. (author)

2007-01-01

356

Conductivity of Graphene with Resonant and Nonresonant Adsorbates  

Science.gov (United States)

We propose a unified description of transport in graphene with adsorbates that fully takes into account localization effects and loss of electronic coherence due to inelastic processes. We focus in particular on the role of the scattering properties of the adsorbates and analyze in detail cases with resonant or nonresonant scattering. For both models, we identify several regimes of conduction, depending on the value of the Fermi energy. Sufficiently far from the Dirac energy and at sufficiently small concentrations, the semiclassical theory can be a good approximation. Near the Dirac energy, we identify different quantum regimes, where the conductivity presents universal behaviors.

Trambly de Laissardière, Guy; Mayou, Didier

2013-10-01

357

Room temperature phosphorescence of nitrogen heterocycles adsorbed on silica gel  

Energy Technology Data Exchange (ETDEWEB)

The room temperature phosphorescence (RTP) of benzo(f)-quinoline adsorbed on several silica gel samples was investigated by luminescence, reflectance, and infrared spectroscopy to obtain a better understanding of the analytical conditions needed for strong RTP. The results showed that silica gel chromatoplates containing a polymeric binder with carboxyl groups were the best samples for inducing strong RTP from benzo(f)quinoline. The polymer itself was essential for inducing strong RTP. It was postulated that benzo(f)quinoline was adsorbed flatly on the surface with the carboxyl groups anchoring benzo(f)quinoline via hydrogen bonding with ..pi.. electrons. 5 figures, 4 tables.

Ford, C.D.; Hurtubise, R.J.

1980-04-01

358

Adsorbed liposome deformation studied with quartz crystal microbalance  

Science.gov (United States)

Deformation of surface-adsorbed liposomes is an important parameter that governs the kinetics of their transformations, but one that is very difficult to measure in the case of nm-size liposomes. We investigate the deformation of dimyristoyl phosphatidyl choline liposomes by quartz crystal microbalance (QCM) as a function of temperature and show that it follows the dependence of this lipid's bending modulus on temperature, as expected from theoretical considerations. To corroborate our approach, we model QCM response from adsorbed liposomes by explicitly considering their shape and mechanical properties.

Reviakine, Ilya; Gallego, Marta; Johannsmann, Diethelm; Tellechea, Edurne

2012-02-01

359

Electrochemical Studies of Paraquat Adsorbed onto Crystalline Apatite  

Directory of Open Access Journals (Sweden)

Full Text Available The carbon paste electrode (CPE) has been used to analyze the electrochemical behavior of paraquat (PQ) adsorbed onto synthesized hydroxyapatite phosphocalcique (HAP) in K2SO4 (0.1M). The cyclic voltammetry results obtained corrobate with square wave voltammetry. The influence of variables such as the concentration of paraquat adsorbed onto apatite (PQ/HAP), and the potential scan rate was tested.X-ray diffraction analysis (XRD), Fourier transformed infrared spectroscopy (FTIR) analysis and inductively coupled plasma-atomic emission spectrometry (ICP, AES) were used for characterization of the apatite.

Moulay Abderrahim EL MHAMMEDI; Abdelilah CHTAINI

2007-01-01

360

Simulations of the kinetic friction due to adsorbed surface layers  

CERN Document Server

Simulations of the kinetic friction due to a layer of adsorbed molecules between two crystalline surfaces are presented. The adsorbed layer naturally produces friction that is consistent with Amontons' laws and insensitive to parameters that are not controlled in experiments. The kinetic friction rises logarithmically with velocity as in many experimental systems. Variations with potential parameters and temperature follow variations in the static friction. This correlation is understood through analogy with the Tomlinson model and the trends are explained with a hard-sphere picture.

He, G; He, Gang; Robbins, Mark O.

2000-01-01

 
 
 
 
361

Cauliflower-like CuI nanostructures: Green synthesis and applications as catalyst and adsorbent  

International Nuclear Information System (INIS)

Highlights: ? In this study we report a green, environment-friendly, efficient, and direct one-step process for the preparation of CuI cauliflower. ? The as-formed CuI cauliflower shows excellent catalytic activity for coupling reaction between benzylamine and iodobenzene. ? The cauliflower-like CuI nanostructures have been successfully demonstrated as adsorbent for Cd (II) with high removal capacity. ? To the best of our knowledge, it is the first report that nanostructured CuI acts as catalyst for coupling reaction and adsorbent for heavy metal ion. ? It is also a good example for the organic combination of green chemistry and functional materials. - Abstract: Cauliflower-like CuI nanostructures is realized by an ampicillin-assisted clean, nontoxic, environmentally friendly synthesis strategy at room temperature. The morphology, composition, and phase structure of as-prepared powders were characterized by field emission scanning electron microscopy, X-ray diffraction, and X-ray photoelectron spectroscopy. The results show that ampicillin plays dual roles, reducing and morphology-directing agents, in the formation of the products. A possible growth mechanism of the cauliflower-like CuI nanostructures is tentatively proposed. The preliminary investigations show that the cauliflower-like CuI structure not only exhibits high catalytic activity with respect to coupling reaction between benzylamine and iodobenzene but also possesses high removal capacity for Cd (II), which may be ascribed to the high specific surface area of the special configuration. To the best of our knowledge, it is the first report that cauliflower-like CuI nanoparticles act as catalyst for coupling reaction and adsorbent for heavy metal ion.

2011-08-15

362

Cauliflower-like CuI nanostructures: Green synthesis and applications as catalyst and adsorbent  

Energy Technology Data Exchange (ETDEWEB)

Highlights: > In this study we report a green, environment-friendly, efficient, and direct one-step process for the preparation of CuI cauliflower. > The as-formed CuI cauliflower shows excellent catalytic activity for coupling reaction between benzylamine and iodobenzene. > The cauliflower-like CuI nanostructures have been successfully demonstrated as adsorbent for Cd (II) with high removal capacity. > To the best of our knowledge, it is the first report that nanostructured CuI acts as catalyst for coupling reaction and adsorbent for heavy metal ion. > It is also a good example for the organic combination of green chemistry and functional materials. - Abstract: Cauliflower-like CuI nanostructures is realized by an ampicillin-assisted clean, nontoxic, environmentally friendly synthesis strategy at room temperature. The morphology, composition, and phase structure of as-prepared powders were characterized by field emission scanning electron microscopy, X-ray diffraction, and X-ray photoelectron spectroscopy. The results show that ampicillin plays dual roles, reducing and morphology-directing agents, in the formation of the products. A possible growth mechanism of the cauliflower-like CuI nanostructures is tentatively proposed. The preliminary investigations show that the cauliflower-like CuI structure not only exhibits high catalytic activity with respect to coupling reaction between benzylamine and iodobenzene but also possesses high removal capacity for Cd (II), which may be ascribed to the high specific surface area of the special configuration. To the best of our knowledge, it is the first report that cauliflower-like CuI nanoparticles act as catalyst for coupling reaction and adsorbent for heavy metal ion.

Jiang Yi [College of Chemistry and Environmental Science, Henan Normal University, Xinxiang, Henan 453007 (China); Gao Shuyan, E-mail: shuyangao@htu.cn [College of Chemistry and Environmental Science, Henan Normal University, Xinxiang, Henan 453007 (China); Li Zhengdao; Jia Xiaoxia; Chen Yanli [College of Chemistry and Environmental Science, Henan Normal University, Xinxiang, Henan 453007 (China)

2011-08-15

363

CVD-grown anti-oxidation coatings on C/C and C/SiC composites; Oxidationsschutzschichten auf C/C- und C/SiC- Verbundwerkstoffen durch chemische Gasphasenabscheidung (CVD)  

Energy Technology Data Exchange (ETDEWEB)

Results of a study are presented which examined deposition and performance of multilayer coatings (three layers). The base layer (for adhesive bonding to substrate) consists of pyrolytic carbon (PyC), or carbon-graded silicon carbide films (C-SiC). The second layer (diffusion barrier) consists of hafnium carbide (HfC), and the surface layer material is silicon carbide. (orig./CB) [German] Dieser Arbeit liegt ein Multilayerschutzverbund aus drei Schichten zu Grunde. Die einzelnen Schichten erfuellen dabei folgende Funktionen: die Basisschicht stellt die haftvermittelnde Grundlage zum Substrat (C/C- oder C/SiC- Verbundwerkstoff) dar, die mittlere Schicht dient als Diffusionsbarriere fuer Sauerstoff und die abschliessende Deckschicht als Hochtemperatur-Oxidationsschutz. Als Basisschicht wird pyrolytischer Kohlenstoff (PyC) oder alternativ dazu kohlenstoffgradiertes Siliziumkarbid (C-SiC) aufgebracht. Die darueberliegende Diffusionsbarriere besteht aus Hafniumkarbid (HfC) und die abschliessende Deckschicht aus Siliciumkarbid (SiC). (orig.)

Wunder, V.; Popovska, N.; Emig, G. [Erlangen-Nuernberg Univ., Erlangen (Germany). Lehrstuhl fuer Technische Chemie 1

1999-07-01

364

Relationship between tightness of binding and immunogenicity in an aluminum-containing adjuvant-adsorbed hepatitis B vaccine.  

UK PubMed Central (United Kingdom)

Phospholipid-containing antigens, such as Hepatitis B Surface Antigen (HBsAg), adsorb to aluminum-containing adjuvants by ligand exchange of a phosphate group for a hydroxyl group on the adjuvant surface. In this study, a tightness of binding (TOB) assay was developed to characterize the strength of binding between HBsAg and aluminum hydroxyphosphate sulfate adjuvant containing two levels of phosphate. Antigen desorption was induced using either fluoride or phosphate as a competing ion. HBsAg, formulated as a monovalent or combination vaccine, showed decreased tightness of binding when the amount of phosphate in the adjuvant composition increased, indicating that there was less ligand exchange between HBsAg and the adjuvant. Furthermore, the physicochemical property of TOB was related to enhanced immunogenicity in a murine model. These data show that tightness of binding can be a useful characterization tool, and potential predictor of immunogenicity, during development of vaccines that adsorb to aluminum adjuvants via ligand exchange.

Egan PM; Belfast MT; Giménez JA; Sitrin RD; Mancinelli RJ

2009-05-01

365

Selection of non-adsorbing alkali components  

Energy Technology Data Exchange (ETDEWEB)

This project consists of three phases of laboratory experimental study. In phase I (screening), eight candidate materials, 304SS (serves as a base material for comparison), Hastelloy C-276, Hastelloy X, Haynes No. 188, Allonized 304SS, Pt-coated 304SS, and ceramic-coated 304SS, will be subjected to atmospheric TGA study under the simulated PFBC (oxidizing) environment with and without alkali vapor doping. Each candidate material will be evaluated for its resistance toward alkali-vapor capture. In addition, a post-test metallographic characterization of the sample will be performed to obtain a better understanding of the alkali capture mechanism and material behavior. The material(s) with little or no alkali-vapor adsorption will be selected as the promising material(s) for the Phase II study. In Phase II, the promising material(s) will be further tested in the TGA under elevated pressure to simulate the PFBC environment (in terms of temperature, pressure, and gas composition). The effect of pressure on the extent of alkali-vapor adsorption will be evaluated, and the test samples will be metallographically characterized. The most promising candidate material(s) will be identified and recommended for further tesfing in the actual PFBC environment. In Phase III, four materials will be selected from the eight candidate materials screened in the PFBC environment and will be evaluated for their alkali-vapor capture by atmospheric TGA under the coal gasification fuel gas (reducing) environment. The tested samples will also be metallographically characterized. The most promising material(s) will be identified and recommended for further testing in the actual coal gasification environment.

Lee, S.H.D.; Natesan, K.; Swift, W.M.

1992-01-01

366

Selection of non-adsorbing alkali components  

Energy Technology Data Exchange (ETDEWEB)

This project consists of three phases of laboratory experimental study. In phase I (screening), eight candidate materials, 304SS (serves as a base material for comparison), Hastelloy C-276, Hastelloy X, Haynes No. 188, Allonized 304SS, Pt-coated 304SS, and ceramic-coated 304SS, will be subjected to atmospheric TGA study under the simulated PFBC (oxidizing) environment with and without alkali vapor doping. Each candidate material will be evaluated for its resistance toward alkali-vapor capture. In addition, a post-test metallographic characterization of the sample will be performed to obtain a better understanding of the alkali capture mechanism and material behavior. The material(s) with little or no alkali-vapor adsorption will be selected as the promising material(s) for the Phase II study. In Phase II, the promising material(s) will be further tested in the TGA under elevated pressure to simulate the PFBC environment (in terms of temperature, pressure, and gas composition). The effect of pressure on the extent of alkali-vapor adsorption will be evaluated, and the test samples will be metallographically characterized. The most promising candidate material(s) will be identified and recommended for further tesfing in the actual PFBC environment. In Phase III, four materials will be selected from the eight candidate materials screened in the PFBC environment and will be evaluated for their alkali-vapor capture by atmospheric TGA under the coal gasification fuel gas (reducing) environment. The tested samples will also be metallographically characterized. The most promising material(s) will be identified and recommended for further testing in the actual coal gasification environment.

Lee, S.H.D.; Natesan, K.; Swift, W.M.

1992-11-01

367

Adsorption of sulphur dioxide on carbonaceous materials. I. The influence of the adsorbent texture on the amount adsorbed  

Energy Technology Data Exchange (ETDEWEB)

Adsorption on materials with wide differences in texture has been investigated. Consideration of the t-curve and the Dubinin-Astakhov equation for low-pressure argon isotherms made it possible to establish the prevailing adsorption mechanism. The existence of sub-micropores and narrower micropores affects the amount of SO/SUB/2 adsorbed. No correlation was found between the amount of SO/SUB/2 adsorbed and the specific surface area, the mesopore volume, or the total micropore volume. The materials tested were Norit activated coal, a Polish activated coke, Corax carbon black and Cabot graphitized carbon black. (In Polish)

Grzybek, T.

1981-01-01

368

Titania/CnTAB Nanoskeleton as adsorbent and photocatalyst for removal of alkylphenols dissolved in water.  

UK PubMed Central (United Kingdom)

We report here on the removal of alkylphenols (phenol, 4-n-propylphenol, 4-n-heptylphenol and 4-nonylphenol) dissolved in water using the composite particles of nanocrystalline titania and alkyltrimethylammonium bromide (CnH2n+1N(CH3)3Br, CnTAB; n=12, 14, 16 and 18) (named as TiO2/CnTAB Nanoskeleton) as adsorbents and photocatalysts. In particular, the adsorption of alkylphenols onto TiO2/CnTAB Nanoskeleton in water was investigated in terms of hydrophobic interaction between alkylphenols and CnTAB, surface area, pore structure and crystal size of TiO2/CnTAB Nanoskeleton. We revealed that CnTAB incorporated in the TiO2/CnTAB Nanoskeleton promotes the adsorption of alkylphenols onto TiO2/CnTAB Nanoskeleton due to the hydrophobic interaction between alkylphenols and CnTAB. On the other hand, the surface area, pore structure and crystal size of TiO2/CnTAB Nanoskeleton did not affect the adsorption of alkylphenols onto TiO2/CnTAB Nanoskeleton. We also found that the alkylphenols dissolved in water were completely removed by the combination of adsorption and photocatalytic degradation by the TiO2/CnTAB Nanoskeleton under UV irradiation. These results prove that the TiO2/CnTAB Nanoskeleton acts as in tandem an adsorbent and a photocatalyst for removal of alkylphenols dissolved in water.

Sakai T; Da Loves A; Okada T; Mishima S

2013-03-01

369

Proteome analysis of the plasma protein layer adsorbed to a rough titanium surface.  

UK PubMed Central (United Kingdom)

In this study a label-free proteomic approach was used to investigate the composition of the layer of protein adsorbed to rough titanium (Ti) after exposure to human blood plasma. The influence of the protein layer on the surface free energy (SFE) of the Ti was evaluated by contact angle measurements. Ti discs were incubated with blood plasma for 180 min at 37 °C, and the proteins recovered were subjected to liquid chromatography coupled to tandem mass spectrometry analysis. A total of 129 different peptides were identified and assigned to 25 distinct plasma proteins. The most abundant proteins were fibronectin, serum albumin, apolipoprotein A-I, and fibrinogen, comprising 74.54% of the total spectral counts. Moreover, the protein layer increased the SFE of the Ti (p < 0.05). The layer adsorbed to the rough Ti surface was composed mainly of proteins related to cell adhesion, molecule transportation, and coagulation processes, creating a polar and hydrophilic interface for subsequent interactions with host cells.

Dodo CG; Senna PM; Custodio W; Paes Leme AF; Del Bel Cury AA

2013-01-01

370

Dispersive kinetic of fluorescence decay of alloxazines adsorbed into cellulose  

Science.gov (United States)

The fluorescence decay of alloxazines adsorbed into microcrystalline cellulose shows a complex kinetics suggesting at least three emitting species. The exponential series method and the Albery model were used to calculate the underlying distributions, providing results about the decay rate constants or lifetime distributions.

Krawczyk, Alina; Sikorska, Ewa; Khmelinskii, Igor V.; Sikorski, Marek

2005-09-01

371

Hydraulic properties of adsorbed water films in unsaturated porous media  

Energy Technology Data Exchange (ETDEWEB)

Adsorbed water films strongly influence residual water saturations and hydraulic conductivities in porous media at low saturations. Hydraulic properties of adsorbed water films in unsaturated porous media were investigated through combining Langmuir's film model with scaling analysis, without use of any adjustable parameters. Diffuse double layer influences are predicted to be important through the strong dependence of adsorbed water film thickness (f) on matric potential ({Psi}) and ion charge (z). Film thickness, film velocity, and unsaturated hydraulic conductivity are predicted to vary with z{sup -1}, z{sup -2}, and z{sup -3}, respectively. In monodisperse granular media, the characteristic grain size ({lambda}) controls film hydraulics through {lambda}{sup -1} scaling of (1) the perimeter length per unit cross sectional area over which films occur, (2) the critical matric potential ({Psi}{sub c}) below which films control flow, and (3) the magnitude of the unsaturated hydraulic conductivity when {Psi} < {Psi}{sub c}. While it is recognized that finer textured sediments have higher unsaturated hydraulic conductivities than coarser sands at intermediate {Psi}, the {lambda}{sup -1} scaling of hydraulic conductivity predicted here extends this understanding to very low saturations where all pores are drained. Extremely low unsaturated hydraulic conductivities are predicted under adsorbed film-controlled conditions (generally < 0.1 mm y{sup -1}). On flat surfaces, the film hydraulic diffusivity is shown to be constant (invariant with respect to {Psi}).

Tokunaga, Tetsu K.

2009-03-01

372

Role of quantum vortices in atomic scattering from single adsorbates  

Digital Repository Infrastructure Vision for European Research (DRIVER)

5 pages, 4 figures -- PACS numbers: 79.20.Rf, 34.50.Dy, 34.10.+x, 03.65.Ta , The scattering of He atoms from adsorbed CO molecules on the Pt(111) surface is described within the formalism of quantum trajectories provided by Bohmian mechanics. We show that the main mechanism leading to the formation of ...

Sanz, Ángel S.; Borondo, Florentino; Miret-Artés, Salvador

373

Evaluation of solid adsorbents for collecting atmospheric chlorinated hydrocarbons  

Energy Technology Data Exchange (ETDEWEB)

The comparative efficiency of polyurethane foam (PUF) and Tenax-GC resin for collecting polychlorinated biphenyls (PCB) and chlorinated pesticides from 300-1600 cu m air was determined by side-by-side sampling with each adsorbent in the city of Columbia, South Carolina.

Bidleman, T.F.; Billings, W.N.; Simon, C.G.

1980-07-01

374

EVALUATION OF SOLID ADSORBENTS FOR COLLECTING ATMOSPHERIC CHLORINATED HYDROCARBONS  

Science.gov (United States)

The comparative efficiency of polyurethane foam (PUF) and Tenax-GC resin for collecting polychlorinated biphenyls (PCB) and chlorinated pesticides from 300-1600 cu m air was determined by side-by-side sampling with each adsorbent in the city of Columbia, South Carolina....

375

Adsorption of iodine by silver-impregnated hydrophobic adsorbent  

Energy Technology Data Exchange (ETDEWEB)

Hydrophobic adsorbents, which consist of porous styrene-divinylbenzene copolymer (SDB) impregnated with silver, were developed for the removal of iodine from the dissolver off-gas (DOG). The adsorption of iodine in a simulated off-gas including iodine, NO[sub x] and water vapor was examined by use of an adsorption column packed with the hydrophobic adsorbents. Silver impregnation methods using organic solutions were proposed. By use of dioxan and butylamine, which can swell the SDB easily, silver nitrate and metallic silver were uniformly distributed in the SDB particles. The breakthrough of iodine was not influenced by the presence of NO[sub x] and water vapor. For a macroporous SDB with the pore volume of 1.59 ml/g-SDB and the average pore diameter of 500A, impregnated with metallic silver at silver content of 28 wt%, a high adsorption capacity of 0.14g-I[sub 2]/cm[sup 3]-adsorbent was obtained, compared to that of a commercial adsorbent. AgNO[sub 3]-impregnated silica gel. The impregnated silver was utilized about 91% for the iodine adsorption. (author).

Takeshita, Kenji; Kumagai, Mikio; Takashima, Yoichi (Institute of Research and Innovation, Tokyo (Japan)); Matsumoto, Shiro; Koga, Jiro

1992-12-01

376

Utilization of Coal Fly Ash as CO Gas Adsorbent  

Digital Repository Infrastructure Vision for European Research (DRIVER)

This research focused on coal fly ash fabricated as CO adsorbent. Coal fly ash having grain size of 325 mesh was characterized by XRF, XRD and SEM-EDX. Physical activation was done at temperatures of 5000C, 5200C, 5400C, 5600C, 5800C and...

Dyah Sawitri; Ayu Lasryza

377

?SR investigation of ethyl radicals adsorbed on silica  

International Nuclear Information System (INIS)

[en] ?SR spectra of the ethyl radical adsorbed on porous silica were observed in transverse and in longitudinal magnetic fields in the temperature range 190-298 K. The line widths reflect the dynamic partial averaging of the hyperfine anisotropy due to reorientation and surface diffusion. (orig.)

1993-06-11

378

Raman spectra of CO adsorbed on Ni(100)  

International Nuclear Information System (INIS)

[en] Experimental results are discussed for laser Raman spectra of CO adsorbed on Ni(100) at -131C. Raman shifts are observed at 2050, 2028, 466 and 419 cm-1. Assignments are made for the modes based upon C/sub 2v/ C/sub 4v/ point groups. The assignments are compared with earlier experimental and theoretical work

1982-01-01

379

Raman spectra of CO adsorbed on Ni(100)  

Energy Technology Data Exchange (ETDEWEB)

Experimental results are discussed for laser Raman spectra of CO adsorbed on Ni(100) at -131C. Raman shifts are observed at 2050, 2028, 466 and 419 cm/sup -1/. Assignments are made for the modes based upon C/sub 2v/ C/sub 4v/ point groups. The assignments are compared with earlier experimental and theoretical work.

Bradley, E.B.; Arunkumar, K.A.

1982-02-01

380

Structure and Reactivity of Adsorbed Fibronectin Films on Mica  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Understanding the interactions of adsorbed fibronectin (Fn) with other biomolecules is important for many biomedical applications. Fn is found in almost all body fluids, in the extracellular matrix, and plays a fundamental role in many biological processes. This study found that the structure (confo...

Hull, James R.; Tamura, Glen S.; Castner, David G.

 
 
 
 
381

Supersolidity in quantum films adsorbed on graphene and graphite  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Using quantum Monte Carlo we have studied the superfluid density of the first layer of 4He and H2 adsorbed on graphene and graphite. Our main focus has been on the equilibrium ground state of the system, which corresponds to a registered ?3 × ?3 phase. The perfect solid phase of H2 shows no superflu...

Gordillo Bargueño, Maria Carmen; Cazorla, C.; Boronat Medico, Jordi

382

Supercritical fluid adsorption and desorption of lipids on various adsorbents  

Digital Repository Infrastructure Vision for European Research (DRIVER)

In present work the feasibility of using supercritical fluid chromatography (SFC) for separation of free fatty acids (FFA) and triglycerides has been examined. Lipids such as oleic acid and sunflower oil (containing 96% of triglycerides) were used , adsorption and desorption on adsorbents such as silic...

Škerget, Mojca; Knez, Željko

383

EMERGING TECHNOLOGY REPORT: DEMONSTRATION OF AMBERSORB 563 ADSORBENT TECHNOLOGY  

Science.gov (United States)

The Ambersorb (Rohm and Haas) Adsorbent technology demonstration was conducted over a 12-week period during the spring/summer of 1994 at Site 32/36 of the former Pease Air Force Base, Newington, N.H. he groundwater in this area is contaminated with a number of chlorinated organic...

384

EMERGING TECHNOLOGY REPORT: DEMONSTRATION OF AMBERSORBâ?¢ 563 ADSORBENT TECHNOLOGY  

Science.gov (United States)

The Ambersorbâ?¢ (Rohm and Haas) Adsorbent technology demonstration was conducted over a 12-week period during the spring/summer of 1994 at Site 32/36 of the former Pease Air Force Base, Newington, N.H. The groundwater in this area is contaminated with a number of chlorinated organ...

385

Study of Adsorbents for the Capture of CO2 in Post-combustion. Contribution of CIEMAT to Module 4 of the CENITCO2 Project  

International Nuclear Information System (INIS)

The main goal of CIEMAT within the CENIT-CO2 project has been the development of a process for CO2 capture from combustion flue gases by physical adsorption. In the first stage, screening studies to select promising adsorbents were carried out at laboratory scale, using simplified gas compositions. After that, pilot plant studies were performed using appropriate configurations of promising adsorbents under realistic conditions. CO2 adsorption cyclic capacity of different adsorbents has been studied. Lastly, for the adsorbent selected as most promising, its cyclic efficiency and selectivity for CO2 adsorption in the presence of other gaseous components (SO2, H2O, NO) of the combustion gas has been determined, as well as its performance along multiple sorption-desorption cycles in the presence of simulated combustion gas. None of the studied adsorbents, though being promising since they all have a capture efficiency of about 90%, seem to be susceptible of direct application to CO2 capture by physical adsorption under conditions representative of gases exiting the desulphurization tower of conventional pulverized coal combustion plants. As an alternative, the development of hybrid and regenerable solid sorbents (physical-chemical adsorption) is proposed or the application of new technologies under development such as the electrochemical promotion in capturing CO2. (Author) 33 refs.

2010-01-01

386

Germanium-oxide-coated carbon nanotubes  

International Nuclear Information System (INIS)

An ultrathin coating of individual multi-wall carbon nanotubes with germanium oxide was developed. Coated carbon nanotubes were prepared by in situ gelation of tetramethoxy germanium, forming an amorphous germanium oxide layer. The resulting germanium oxide/carbon nanotube nanocables were characterized by transmission electron microscopy (TEM), TEM/energy-dispersive x-ray spectroscopy, x-ray photoelectron spectroscopy (XPS) and current-voltage measurements. The ?10 nm thin germanium oxide layer provides excellent electrical insulating properties for individual carbon nanotubes.

2009-10-21

387

Natural material adsorbed onto a polymer to enhance immune function  

Directory of Open Access Journals (Sweden)

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

Reinaque AP; França EL; Scherer EF; Côrtes MA; Souto FJ; Honorio-França AC

2012-01-01

388

Self-assembled poly(N-methylaniline)-lignosulfonate spheres: from silver-ion adsorbent to antimicrobial material.  

UK PubMed Central (United Kingdom)

Self-assembled poly(N-methylaniline)-lignosulfonate (PNMA-LS) composite spheres with reactive silver-ion adsorbability were prepared from N-methylaniline by using lignosulfonate (LS) as a dispersant. The results show that the PNMA-LS composite consisted of spheres with good size distribution and an average diameter of 1.03-1.27 ?m, and the spheres were assembled by their final nanofibers with an average diameter of 19-34 nm. The PNMA-LS composite spheres exhibit excellent silver-ion adsorption; the maximum adsorption capacity of silver ions is up to 2.16 g g(-1) at an adsorption temperature of 308 K. TEM and wide-angle X-ray results of the PNMA-LS composite spheres after absorption of silver ions show that silver ions are reduced to silver nanoparticles with a mean diameter of about 11.2 nm through a redox reaction between the PNMA-LS composite and the silver ions. The main adsorption mechanism between the PNMA-LS composite and the silver ions is chelation and redox adsorption. In particular, a ternary PNMA-LS-Ag composite achieved by using the reducing reaction between PNMA-LS composite spheres and silver ions can be used as an antibacterial material with high bactericidal rate of 99.95 and 99.99% for Escherichia coli and Staphylococcus aureus cells, respectively.

Lü QF; Zhang JY; Yang J; He ZW; Fang CQ; Lin Q

2013-08-01

389

Adsorbate structures and catalytic reactions studied in the torrpressure range by scanning tunneling microscopy  

Energy Technology Data Exchange (ETDEWEB)

High-pressure, high-temperature scanning tunneling microscopy (HPHTSTM) was used to study adsorbate structures and reactions on single crystal model catalytic systems. Studies of the automobile catalytic converter reaction [CO + NO {yields} 1/2 N{sub 2} + CO{sub 2}] on Rh(111) and ethylene hydrogenation [C{sub 2}H{sub 4} + H{sub 2} {yields} C{sub 2}H{sub 6}] on Rh(111) and Pt(111) elucidated information on adsorbate structures in equilibrium with high-pressure gas and the relationship of atomic and molecular mobility to chemistry. STM studies of NO on Rh(111) showed that adsorbed NO forms two high-pressure structures, with the phase transformation from the (2 x 2) structure to the (3 x 3) structure occurring at 0.03 Torr. The (3 x 3) structure only exists when the surface is in equilibrium with the gas phase. The heat of adsorption of this new structure was determined by measuring the pressures and temperatures at which both (2 x 2) and (3 x 3) structures coexisted. The energy barrier between the two structures was calculated by observing the time necessary for the phase transformation to take place. High-pressure STM studies of the coadsorption of CO and NO on Rh(111) showed that CO and NO form a mixed (2 x 2) structure at low NO partial pressures. By comparing surface and gas compositions, the adsorption energy difference between topsite CO and NO was calculated. Occasionally there is exchange between top-site CO and NO, for which we have described a mechanism for. At high NO partial pressures, NO segregates into islands, where the phase transformation to the (3 x 3) structure occurs. The reaction of CO and NO on Rh(111) was monitored by mass spectrometry (MS) and HPHTSTM. From MS studies the apparent activation energy of the catalytic converter reaction was calculated and compared to theory. STM showed that under high-temperature reaction conditions, surface metal atoms become mobile. Ethylene hydrogenation and its poisoning by CO was also studied by STM on Rh(111) and Pt(111). Poisoning was found to coincide with decreased adsorbate mobility. Under ethylene hydrogenation conditions, no order is detected by STM at 300 K, as hydrogen and ethylidyne, the surface species formed by gas-phase ethylene, are too mobile. When CO is introduced, the reaction stops, and ordered structures appear on the surface. For Rh(111), the structure is predominantly a mixed c(4 x 2), though there are some areas of (2 x 2). For Pt(111), the structure is hexagonal and resembles the Moire pattern seen when Pt(111) is exposed to pure CO. From these studies it is concluded that CO poisons by stopping adsorbate mobility. This lack of adsorbate mobility prevents the adsorption of ethylene from the gas phase by hindering the creation of adsorption sites.

Hwang, Kevin Shao-Lin

2003-05-23

390

Novel adsorbent applicability for decontamination of printing wastewater  

Science.gov (United States)

Adsorption capacity of clayey minerals can be enhanced by replacing the natural exchangeable cations with organic cations, which makes the clay surface more hydrophobic. Different solids such as activated carbon, clay minerals, zeolites, metal oxides and organic polymers have been tested as effective adsorbents. On a global scale, clays have a large applicability for decontamination, purification of urban and industrial residual waters, protection of waste disposal areas, and purification of industrial gases and so on. Clay derivative materials with high adsorption capacities are very attractive from an economical point of view. Due to the economic constraints, a development of cost effective and clean processes is desired. Adsorption processes has proved to be the most effective, especially for effluents with moderate and low heavy metal concentrations, as like as in printing wastewaters. Among several removal technologies, the adsorption of Zn(II) ion onto NZ, B, pure C and C with PEG 600 addition could be of great importance for the printing wastewaters purification. However, the newly designed adsorbent of the defined pore size distribution and phase structure considered as the most suitable material for Zn(II) ion removal. The values of distribution coefficient (Kd) increased with decreasing of the adsorbent amount. The Kd values depend also on the type of used adsorbent, the following increased order is obtained: NZ Langmuir > DKR. The study also showed that the fired clay modified with PEG 600 addition has great potential (up to 93.5%) to remove Zn(II) ion from printing wastewaters. The results showed that fired clay, fired clay modified with polymer addition, natural zeolite and bentonite can be used for Zn(II) ion removal from printing wastewaters by adsorption method in laboratory batch mode. Based on higher affinity to the Zn(II) ion adsorption than fired clay, bentonite and zeolite it was concluded that feasibility of newly designed clayey adsorbent, fired clay with 5 mass% PEG addition is very good. A new designed clayey adsorbent is an effective and economical alternative for the Zn(II) ion removal from printing wastewaters. Acknowledgment: The authors acknowledge the financial support of the Ministry of Education, Science and Technological Development of the Republic of Serbia (Projects No. TR 34014, III 45008 and III 46009).

Kiurski, Jelena; Oros, Ivana; Ranogajec, Jonjaua; Kecic, Vesna

2013-04-01

391

Composite mixed foliage fertilizer and its preparation  

UK PubMed Central (United Kingdom)

A composite mixed foliage fertilizer and its production are disclosed. The fertilizer consists of amino-acid dry powder, iron, zinc, fast-effective nitrogen, phosphor and potassium fertilizer, plant growth regulator sodium nitrate, leaf wetting agent, adsorbent, penetrating agent and synergistic agent. It has better fertilizer effect, solubility and biological activity and more product yield.

GAO SHULIN ZHANG

392

Biodegradation of medium chain hydrocarbons by Acinetobacter venetianus 2AW immobilized to hair-based adsorbent mats.  

UK PubMed Central (United Kingdom)

The natural attenuation of hydrocarbons can be hindered by their rapid dispersion in the environment and limited contact with bacteria capable of oxidizing hydrocarbons. A functionalized composite material is described herein, that combines in situ immobilized alkane-degrading bacteria with an adsorbent material that collects hydrocarbon substrates, and facilitates biodegradation by the immobilized bacterial population. Acinetobacter venetianus 2AW was isolated for its ability to utilize hydrophobic n-alkanes (C10-C18) as the sole carbon and energy source. Growth of strain 2AW also resulted in the production of a biosurfactant that aided in the dispersion of complex mixtures of hydrophobic compounds. Effective immobilization of strain 2AW to the surface of Ottimat™ adsorbent hair mats via vapor phase deposition of silica provided a stable and reproducible biocatalyst population that facilitates in situ biodegradation of n-alkanes. Silica-immobilized strain 2AW demonstrated ca. 85% removal of 1% (v/v) tetradecane and hexadecane within 24 h, under continuous flow conditions. The methodology for immobilizing whole bacterial cells at the surface of an adsorbent, for in situ degradation of hydrocarbons, has practical application in the bioremediation of oil in water emulsions. Published 2011 American Institute of Chemical Engineers Biotechnol Prog., 2011.

Luckarift HR; Sizemore SR; Farrington KE; Fulmer PA; Biffinger JC; Nadeau LJ; Johnson GR

2011-11-01

393

Spectroscopic study of the Eu(fod)3 complex adsorbed on a 3-trimethoxypropylthioethylamine modified silica surface  

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Full Text Available By using 3-mercaptopropyltrimethoxysilane and ethylenediamine as precursors, the compound 3-trimethoxypropylhioethylamine was synthesized, and then used as a silylating agent to obrtain, through a sol-gel process, an organicmodification of a silica-gel sample. Asurface thus modified was used as a substrate for the adsorption of the luminescent Eu(fod)3·2H2O complex. Eu(fod)3·2H2O and the silicon hybrid were mixed in stoichiometric amounts to produce samples with 1 %, 5 % and 10 % (m/m) of adsorbed complex. The adsorbed complex was then studied from the spectroscopic point of view. The lifetimes measured for the emission process are 476, 542 and 566 ms for 1 %, 5 % and 10 % samples, respectively. Furthermore, comparison with experimental data for n-[3(trimethoxysilyl) propyl]-ethylenediamine modified silica gel surfaces emphasizes the prominenet role of the chemical composition of the silica modified surface on the spectroscopic properties of the adsorbed complex.

ROBSON F. DE FARIAS; SEVERINO ALVES JR.; MONICA F. BELIAN; MAGDAR. S. VIEIRA; JUCIMAR M. DE SOUZA; GILMARA G. PEDROSA; GILBERTO F. DE SA

2004-01-01

394

Dynamic separation of Szilard-Chalmers reaction products applied to the trioxalatochromium ion adsorbed on anionic exchange resin  

International Nuclear Information System (INIS)

A method of dynamic elution of recoiled 51Cr+3, formed by the Szilard-Chalmers reaction during the irradiation of trioxalatochromium ion adsorbed on anionic exchange resin is presented. The influence of some factors on the separation yield of chromium-51, such as: composition, concentration and flow rate of eluent, mesh size of the resin and irradiation time are studied. The results are compardd with those obtained by the static method, in which the recoiled atom is separated from the target after irradiation. Because of the high separation yield of chromium-51, the method of dynamic separation is proposed for routine production of this elemnt, with high specific activities. (author)

1979-01-01

395

Experimental investigation of contact resistance in adsorber of solar adsorption refrigeration  

Energy Technology Data Exchange (ETDEWEB)

The key component of a solar adsorption refrigeration unit is the adsorber packed with an adsorbent such as zeolite, active carbon and CaCI{sub 2}. One essential problem faced is the poor heat transfer in adsorbers, which strongly influences the performance of the system. Poly-aniline, with the advantage of superior thermal conduction, was introduced into an adsorber to increase the thermal conductivity of the adsorbents. As the thermal conductivity coefficient of adsorbent in the adsorber is enhanced, the thermal contact resistance of the interface becomes a significant proportion and needs to be improved. The heat transfer of solid interfaces, particularly the effects of the adsorbent granule or block with rough surfaces, is studied in this paper. Methods for decreasing the contact resistance using spreading adhesive or exerting pressure on the interface are presented and analysed. A test facility and relevant procedure are developed to measure the effects of different interfaces on the contact resistance. The heat transfer at the interface between the copper surface and the adsorbent granule or block is investigated, and its effect in improving the thermal performance of the adsorber in solar adsorption refrigeration is compared. The experimental results show that exerting pressure or spreading adhesive on the interface can reduce the contact resistance significantly without affecting the mass transfer of the adsorbent in an adsorber. (author)

Dongsheng Zhu [Hong Kong Polytechnic University (China). Dept. of Building Services Engineering; South China University of Technology, Guangzhou (China). Research Institute of Chemical Engineering; Shengwei Wang [Hong Kong Polytechnic University (China). Dept. of Building Services Engineering

2002-09-01

396

Transformations of carbon adsorbates on graphene substrates under extreme heat.  

UK PubMed Central (United Kingdom)

We describe new phenomena of structural reorganization of carbon adsorbates as revealed by in situ atomic-resolution transmission electron microscopy (TEM) performed on specimens at extreme temperatures. In our investigations, a graphene sheet serves as both a quasi-transparent substrate for TEM and as an in situ heater. The melting of gold nanoislands deposited on the substrate surface is used to evaluate the local temperature profile. At annealing temperatures around 1000 K, we observe the transformation of physisorbed hydrocarbon adsorbates into amorphous carbon monolayers and the initiation of crystallization. At temperatures exceeding 2000 K the transformation terminates in the formation of a completely polycrystalline graphene state. The resulting layers are bounded by free edges primarily in the armchair configuration.

Westenfelder B; Meyer JC; Biskupek J; Kurasch S; Scholz F; Krill CE 3rd; Kaiser U

2011-12-01

397

Allantoin as a solid phase adsorbent for removing endotoxins.  

UK PubMed Central (United Kingdom)

In this study we present a simple and robust method for removing endotoxins from protein solutions by using crystals of the small-molecule compound 2,5-dioxo-4-imidazolidinyl urea (allantoin) as a solid phase adsorbent. Allantoin crystalline powder is added to a protein solution at supersaturated concentrations, endotoxins bind and undissolved allantoin crystals with bound endotoxins are removed by filtration or centrifugation. This method removes an average of 99.98% endotoxin for 20 test proteins. The average protein recovery is ?80%. Endotoxin binding is largely independent of pH, conductivity, reducing agent and various organic solvents. This is consistent with a hydrogen-bond based binding mechanism. Allantoin does not affect protein activity and stability, and the use of allantoin as a solid phase adsorbent provides better endotoxin removal than anion exchange, polymixin affinity and biological affinity methods for endotoxin clearance.

Vagenende V; Ching TJ; Chua RJ; Gagnon P

2013-08-01

398

Stretching of a chain polymer adsorbed at a surface  

CERN Multimedia

In this paper we present simulations of a surface-adsorbed polymer subject to an elongation force. The polymer is modelled by a self-avoiding walk on a regular lattice. It is confined to a half-space by an adsorbing surface with attractions for every vertex of the walk visiting the surface, and the last vertex is pulled perpendicular to the surface by a force. Using the recently proposed flatPERM algorithm, we calculate the phase diagram for a vast range of temperatures and forces. The strength of this algorithm is that it computes the complete density of states from one single simulation. We simulate systems of sizes up to 256 steps.

Krawczyk, J; Rechnitzer, A; Owczarek, A L

2004-01-01

399

Radiolysis of alanine adsorbed in a clay mineral  

International Nuclear Information System (INIS)

[en] Optical activity in molecules is a chemical characteristic of living beings. In this work, we examine the hypothesis of the influence of different mineral surfaces on the development of a specific chirality in organic molecules when subjected to conditions simulating the primitive Earth during the period of chemical evolution. By using X-ray diffraction techniques and HPLC/ELSD to analyze aqueous suspensions of amino acids adsorbed on minerals irradiated in different doses with a cobalt-60 gamma source, the experiments attempt to prove the hypothesis that some solid surfaces (like clays and meteorite rocks) may have a concentration capacity and protective role against external sources of ionizing radiation (specifically ?-ray) for some organic compounds (like some amino acids) adsorbed on them. Preliminary results show a slight difference in the adsorption and radiolysis of the D-and L-alanine

2013-07-03

400

Radiolysis of alanine adsorbed in a clay mineral  

Energy Technology Data Exchange (ETDEWEB)

Optical activity in molecules is a chemical characteristic of living bein