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1

Composite silicide oxide coatings on refractory metals  

International Nuclear Information System (INIS)

Possibilities of laser technology application for dense ZrO2 or ZrO2-Y2O3 type coatings deposition on scalded molybdenum and for metallic under layers formation for the following silicides coatings deposition on niobium and molybdenum were studied. The method allowing to deposit composite coatings on refractory metals using diffusion, dross ing and laser techniques was developed. Figs. 4

1995-01-01

2

Luminescence of europium-doped anode oxide-coated films on the multilayer titanium-tantalum compositions  

International Nuclear Information System (INIS)

Luminescence of europium in anode oxide-coated films on thin-film titanium-tantalum compositions and process of their anode oxidation by means of chronovoltamperemetry at different order of metallic layers and annealing temperatures were investigations. Correlation of luminescence spectra and diagram of chronovoltamperemetry was shown. Luminescence spectra of samples are characterized by a few types of luminescent center corresponding to Eu3+ and the base

2001-01-01

3

Preparation of composite adsorbents and their characteristics  

International Nuclear Information System (INIS)

Composite adsorbents were prepared and tested for their ability to remove UO22+ in aqueous solution. Synthetic zeolite (zeolite-X) and natural zeolite (clinoptilolite) as an active component were mixed with polyacrylonitrile (PAN) solution as a binder to form the PAN-zeolite-X (composite-X) and PAN-clinoptilolite (composite-C) composite adsorbents. Optimum preparation conditions for the composites were determined. Effects of various parameters on the preparation of the composites were investigated. Each of the prepared composite adsorbents was treated with UO2(NO3)2 x 6H2O and Th(NO3)4 x 4H2O in aqueous solution to determine their sorption capacities. It was found that both composites have about four times higher thorium than uranium uptake capacity. XRD-diffraction patterns were obtained for zeolite-X, composite-X, clinoptilolite and composite-C. Surface area and cation exchange capacities (CEC) were also determined for both composites. (author)

2005-10-01

4

New carbon-silica composite adsorbents from elutrilithe  

Energy Technology Data Exchange (ETDEWEB)

Carbon-silica composite adsorbents with high surface area and pore volume were prepared from natural elutrilithe. The elutrilithe was chemically activated with K{sub 2}CO{sub 3} at 1123 K and then dissolved in water. The textural and adsorptive properties of the composite adsorbents can be adjusted by varying the pH and concentration of the sol mixture and the gel aging temperature. Composite adsorbents prepared at low concentration have high adsorption capacities for both water (43.4%) and cyclohexane (32.0%), exceeding those of ordinary commercial silica gel and active carbon. The adsorbents prepared at high concentration are more hydrophobic in nature, with adsorption capacities for water and cyclohexane of 18.5 and 41.5%, respectively. The composite adsorbents are resistant to repetitive adsorption and regeneration cycles.

Deng, X.; Yue, Y.; Gao, Z. [Fudan Univ., Shanghai (China). Dept. of Chemistry

1998-10-01

5

Kinetic study of lead adsorption to composite biopolymer adsorbent  

Energy Technology Data Exchange (ETDEWEB)

A kinetic study of lead adsorption to composite biopolymer adsorbents was carried out. Spherical and membranous adsorbents containing two biopolymers, humic acid and alginic acid, were used for lead adsorption in dilute acidic solutions. The shrinking core model derived by M.G. Rao and A.K. Gupta was applied to describe the rate process of lead adsorption to spherical adsorbents (average radii of 0.12, 0.15, and 0.16 cm). Furthermore, the shrinking core model was modified and adapted for description of the rate process of lead adsorption to membranous adsorbent (average thickness of 0.0216 cm). The adsorption rate process for both the cases was well described and average apparent lead diffusion coefficients of about 6 {times} 10{sup {minus}6} and 7 {times} 10{sup {minus}6} cm{sup 2}/s were found for the spherical and membranous adsorbents, respectively.

Seki, H.; Suzuki, A. [Hokkaido Univ., Hakodate (Japan). Dept. of Marine Bioresources Chemistry

1999-03-15

6

Kinetic Study of Lead Adsorption to Composite Biopolymer Adsorbent.  

Science.gov (United States)

A kinetic study of lead adsorption to composite biopolymer adsorbents was carried out. Spherical and membranous adsorbents containing two biopolymers, humic acid and alginic acid, were used for lead adsorption in dilute acidic solutions. The shrinking core model derived by M. G. Rao and A. K. Gupta (Chem. Eng. J. 24, 181, 1982) was applied to describe the rate process of lead adsorption to spherical adsorbents (average radii of 0.12, 0.15, and 0.16 cm). Furthermore, the shrinking core model was modified and adapted for description of the rate process of lead adsorption to membranous adsorbent (average thickness of 0.0216 cm). The adsorption rate process for the both cases was well described and average apparent lead diffusion coefficients of about 6 x 10(-6) and 7 x 10(-6) cm2 s-1 were found for the spherical and membranous adsorbents, respectively. Copyright 1999 Academic Press. PMID:10049553

Seki; Suzuki

1999-03-15

7

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.

Satishchandra V. Joshi

2012-01-01

8

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

Digital Repository Infrastructure Vision for European Research (DRIVER)

The protective ceramic coatings were prepared on SiC particle reinforced magnesium matrix composite by microarc oxidation (MAO) surface treatment technique. The surface morphology, cross-sectional microstructure and phase constituent of ceramic coatings were analyzed. And the microhardness profile, thermal shock resistance and electrochemical corrosion behavior of the coatings were measured. The ceramic coating consists of MgO, Mg2SiO4 and a few phases related to the ele...

Xue Wen-bin, Jin Qian

2009-01-01

9

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, 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 pa...

2011-01-01

10

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

11

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

12

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

2011-04-01

13

Uranium extraction from sea water with composite adsorbents, (4)  

International Nuclear Information System (INIS)

Composite hydrous titanium(IV)-iron(II) oxides prepared by precipitation from homogeneous solutions were studied with a view to developing magnetic adsorbents for uranium extraction from sea water. Higher uranium adsorption capacity was registered with homogeneous than with heterogeneous solution used for preparing the oxide. The adsorbents for uranium prepared from homogeneous solution moreover were found to require the copresence of urea and a suitable anion such as So42-, in order to provide strongly active adsorption of uranium. The value of saturated magnetization of the composite hydrous oxides decreased with increasing titanium mole fraction up to 0.75, increase of the titanium mole fraction had, on the other hand, the effect of enhancing uranium adsorption capacity, which however saturated beyond 0.75 titanium mole fraction. The change of enthalpy brought by the uranium adsorption on the composite hydrous titanium(IV)-iron(II) oxides was 10 kcal/mol, and the amount of change independent of the conditions of precipitation. (author)

1980-01-01

14

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

International Nuclear Information System (INIS)

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

2011-06-01

15

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

International Nuclear Information System (INIS)

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

2011-10-01

16

Adsorption of Radioactive Chromium onto Iron Oxide Coated Sand  

International Nuclear Information System (INIS)

Iron oxide coated sand (IOCS) has been prepared and used as granular sorbent for 51Cr radionuclide at different and specified concentration Ievels in aqueous solutions of constant ph value. Effect of different parameters such as: ph variation, contact time, 51Cr ion concentration and variation of temperature on the adsorption of the radionuclide onto IOCS material have been discussed. At high ph value about 9()% of 51Cr is adsorbed onto IOCS from the aqueous solution, The sorption capability of 51Cr and the effect of ion concentration on the adsorbitivity have been discussed. Adsorption isotherms of Langmuir and Freundlich were expressed and their adsorption isotherm parameters are tabulated

2008-05-01

17

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

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

Azhar Abdul Halim

2011-06-01

18

Controlled microstructure oxide coating for chemical sensors.  

Science.gov (United States)

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 bas...

G. C. Frye C. J. Brinker C. S. Ashley S. L. Martinez T. Bein

1990-01-01

19

The adsorption refrigeration characteristics of alkaline-earth metal chlorides and its composite adsorbents  

Energy Technology Data Exchange (ETDEWEB)

A study was conducted on the adsorption characteristics of the adsorption refrigeration working pairs using alkaline-earth metal chlorides as adsorbents and ammonia as refrigerant. The adsorption isotherms between alkaline-earth metal chlorides and nitrogen were studied. The study shows that the adsorbents of CaCl{sub 2}, SrCl{sub 2} provide better adsorption capability associated with ammonia when compared to that of MgCl{sub 2}, BaCl{sub 2}. CaSO{sub 4} was added into the CaCl{sub 2}, SrCl{sub 2} with a mass ratio 20%, respectively, in order to solve the swelling and smashing problems encountered with CaCl{sub 2}, SrCl{sub 2} adsorbent particles. The adsorption refrigeration experiments of composite adsorbents were investigated. The results show that the refrigeration capacity of the unit adsorbent of CaCl{sub 2}/CaSO{sub 4} is 1.26 times higher than that of CaCl{sub 2}, and SrCl{sub 2}/CaSO{sub 4} is 1.6 times higher than that of SrCl{sub 2} at 100 C. The mechanism of NH{sub 3} adsorption and the gelatification of CaSO{sub 4} were also discussed. BET (Brunauer-Emmett-Teller) specific surface area and pore structure of adsorbents were examined. Results show that the BET specific surface area and pore structure of composite adsorbents are retained well. This study indicates that the refrigeration capacity could be enhanced by compositing the adsorbents which indicates that composite adsorbents can perform better in adsorption refrigeration, and can be employed in adsorption refrigeration system using low-grade heat source. (author)

Wang, L.; Chen, L.; Wang, H.L.; Liao, D.L. [The School of Chemistry and Chemical Engineering, South China University of Technology, Guangzhou 510640, GuangDong (China)

2009-04-15

20

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

Science.gov (United States)

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. PMID:22137176

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

2012-01-15

 
 
 
 
21

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

Digital Repository Infrastructure Vision for European Research (DRIVER)

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, we...

DEYI ZHANG; YING MA; HUIXIA FENG; YUAN HAO

2012-01-01

22

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

Directory of Open Access Journals (Sweden)

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

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

2009-07-01

23

Sorption of U(VI) on natural sepiolite and sepiolite-agar agar composite adsorbent  

International Nuclear Information System (INIS)

Adsorption of uranium (VI) ions onto clay minerals is one of the significant reactions affecting the transport of uranium in the environment. The use of composite adsorbents for the removal of metal ions and radionuclide from industrial wastes has attracted great interest to researchers in recent years[1]. In this study, natural sepiolite type clay and an organic compound, agar agar, were chosen as the adsorbent material. Composite adsorbent was prepared from sepiolite and agar agar. Adsorption of uranium (VI) on this composite and on natural sepiolite adsorbent was investigated. Thermodynamic investigations were carried out to get more information about the adsorption of uranium. Adsorption of U (VI) has been studied as a function of solution pH, time, temperature and initial concentration of uranium on natural sepiolite and agar agar composite. The maximum sorption yield of U (VI) on composite and on sepiolite from batch experiments is calculated approximately 89% and 76% respectively in the optimum experimental adsorption condition. The adsorption data were fitted to Freundlich and Dubinin-Radushkevich (D-R) adsorption isotherms. Using the experimental data obtained different temperatures, thermodynamic constants ?Hdegree, ?Sdegree and ?Gdegree were calculated. The results show that the adsorption process on natural sepiolite and sepiolite-agar agar composite are both egzothermic natures. [1] S. M. Hasany, M. M. Saeed, M. Ahmed, J. Radioanal. Nucl. Chem. Vol. 252 (3), 477-484 (2002)

2006-09-06

24

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

25

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

Scientific Electronic Library Online (English)

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

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

26

Structure and decorative properties of titanium oxide coatings deposited from separated low-temperature plasma fluxes  

International Nuclear Information System (INIS)

Using X-ray diffraction analysis the structure and phase composition of titanium oxide coatings on the substrate of carbon steel 08kp were investigated in dependence on conditions of ion-plasma deposition. Oxygen partial pressure in a vacuum chamber was shown to be the most important parameter which determines the type of polymorphous modification and lattice constants of oxides. Depending on the above-mentioned parameter the coating can be single phase or constitute a mixture of phases. Unambiguous relationship of processing parameters to phase composition and optical properties of oxide coatings was established. 9 refs

1996-01-01

27

The base metal of the oxide-coated cathode  

Science.gov (United States)

The oxide-coated cathode has been the most widely used electron emitter in vacuum electronic devices. From one manufacturing company to another the emissive oxide is either a double—Ba, Sr—or a triple—Ba, Sr, Ca—oxide, having always the same respective compositions. Conversely, the base metal composition is very often proprietary because of its importance in the cathode emission performances. The present paper aims at explaining the operation of the base metal through a review. After a brief introduction, the notion of activator is detailed along with their diffusivities and their associated interfacial compounds. Then, the different cathode life models are described prior to few comments on the composition choice of a base metal. Finally, the specificities of the RCA/Thomson "bimetal" base metal are presented with a discussion on the optimized composition choice illustrated by a long-term life-test of five different melts.

Poret, F.; Roquais, J. M.

2005-09-01

28

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

Science.gov (United States)

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

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

2012-02-01

29

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

Energy Technology Data Exchange (ETDEWEB)

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

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

2013-07-01

30

Preparation and characterization of aluminium oxide coatings  

International Nuclear Information System (INIS)

Due to the importance of aluminium oxide coatings in industry and fusion reactor programme, its properties have been studied after depositing it on different substrates by electron beam evaporation method. Characterization of the coatings have been carried out using X-ray diffraction, scanning electron microscopy, Auger electron spectroscopy and Rutherford backscattering analysis. Coating adhesion is quite good (typically, the value 725 Kg/cm2 on monel-400). Results have been analysed and discussed. (author). 14 refs., 3 figures

1987-01-01

31

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

International Nuclear Information System (INIS)

To clarify the technical problems existing in the extraction process of uranium from sea water, uranium was extracted from natural sea water, with the granulated C-Ti-OH composite adsorbent. The adsorption of uranium from sea water was carried out by using the fixed bed that had been designed in our laboratory. The uranium recovery from the sea water was 13.9 % in the adsorption process of 56sub(d). The adsorbed uranium was eluted from the adsorbent with 0.5 sub(N) NaHCO"3-0.5 sub(N) Na"2CO"3 soln. at 70_0C. The elution recovery was 97.4 % after 35 h. The uranium contained in the eluate was concentrated in the anion exchange process to 20 times as much as in the eluate, and then 100 times in the solvent extraction process with oxine-chloroform and TOA- kerosene. About 0.7 g of yellow cake was prepared from natural sea water, and it was identified to be 2UO"2.NH"3.3H"2O by X-ray diffraction method and X-ray fluorometry. (author)

1981-01-01

32

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

Science.gov (United States)

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

Ceylan, ?eyda; Odaba??, Mehmet

2013-12-01

33

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

Directory of Open Access Journals (Sweden)

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

F. Asghari

2012-01-01

34

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

Science.gov (United States)

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

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

2014-05-01

35

Removal of dieldrin from aqueous solution by a novel triolein-embedded composite adsorbent  

International Nuclear Information System (INIS)

In this study, a novel triolein-embedded activated carbon composite adsorbent (CA-T) was prepared and applied for the adsorption and removal of dieldrin from aqueous systems. Experiments were carried out to investigate the adsorption behavior of dieldrin on CA-T, including adsorption isotherms, adsorption kinetics, the influence of initial concentration, temperature, shaking speed, pH and the addition of humic acid (HA) on adsorption. The adsorption isotherms accorded with Freundlich equation. Three kinetics models, including pseudo-first-order, pseudo-second-order and intraparticle diffusion models, were used to fit the experimental data. By comparing the correlation coefficients, it was found that both pseudo-second-order and intraparticle diffusion models were used to well describe the adsorption of dieldrin on CA-T. The addition of HA had little effect on dieldrin adsorption by CA-T. Results indicated that CA-T appeared to be a promising adsorbent for removing lipophilic dieldrin in trace amount, which was advantageous over pure granular activated carbon (GAC). The adsorption rate increased with increasing shaking speed, initial concentration and temperature, and remained almost unchanged in the pH range of 4-8. Thermodynamic calculations indicated that the adsorption reaction was spontaneous with a high affinity and the adsorption was an endothermic reaction

2007-03-06

36

Macrosorb Kieselguhr-agarose composite adsorbents. New tools for downstream process design and scale up. Scientific note.  

Science.gov (United States)

Incompressible Macrosorb composite adsorbents, while retaining all the desirable properties of traditional agarose-based hydrogel media, overcome the operational limitations imposed by the use of soft hydrogels: They permit useful application of fast flow rates without restrictions on bed depth and they can be used in fluidized bed mode. Considerations which are important when contemplating scaled-up processing are discussed. A comparative cost estimate for a production process for extracting albumin from bovine serum in column equipment illustrates the various advantages which may be exploited when using a composite adsorbent in place of a conventional soft gel equivalent. PMID:2845858

Bite, M G; Berezenko, S; Reed, F J; Derry, L

1988-08-01

37

Effects of temperature and adsorbates on the composition profile of Pt-Rh nanocatalysts A comparative study  

CERN Multimedia

Monte-Carlo simulation technique has been used to investigate the effect of temperature and adsorbed gases on the composition profile of unsupported Pt-Rh nanocatalysts. For a 2406 atom fcc cubo-octahedral Pt$_{\\rm{}50}$Rh$_{\\rm{}50}$ nanocatalyst the shell-wise composition for all the eight shells has been simulated. For the temperatures 700 K, 1000 K and 1300 K, the top shell of clean Pt-Rh nanocatalysts is found to be mildly Pt-enriched, while the second shell is Pt-depleted. The Pt concentration of the top shell shows a maximum at T = 1000 K. In presence of a quarter monolayer of adsorbed oxygen the top shell shows Rh enrichment, while all the other shells show Pt-enrichment. This is true for all the three temperatures for which the composition profiles have been studied.

De Sarkar, A; Sarkar, Abir De; Khanra, Badal C.

2001-01-01

38

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

Science.gov (United States)

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

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

1999-01-01

39

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

40

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

Energy Technology Data Exchange (ETDEWEB)

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

Karduck, P.; Burchard, W.G.; Mallener, M.

1988-07-01

 
 
 
 
41

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

International Nuclear Information System (INIS)

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

1988-01-01

42

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

International Nuclear Information System (INIS)

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

2012-06-30

43

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

Science.gov (United States)

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. PMID:23423866

Khan, Tabrez Alam; Chaudhry, Saif Ali; Ali, Imran

2013-08-01

44

Silicon oxide coatings as protection against corrosion  

International Nuclear Information System (INIS)

Silicon oxide films (SiO_x (0< or approx.x< or approx.2)) were deposited onto Inconel 617 alloy for the purpose of corrosion protection in an impure helium environment. The protective behaviour of the deposited films was examined as a function of their chemical composition. The hypostoichiometric SiO_x (x<2) coatings showed poor protective effects. Rather, they enhanced carburization of the Inconel 617 substrate. This is because the interdiffusion of silicon and nickel is faster than the oxidation of SiO_x to form protective SiO_2. In the helium environment used, the rate of supply of oxygen was quite low. Stoichiometric SiO_2 coatings, however, showed good protective qualities. They protected the Inconcel 617 substrate from carburization and from selective oxidation at 1170 and 1270 K for 200 h. However, some deterioration in the protective effect is expected for longer exposure to this environment at 1270 K. (orig.)

1986-12-01

45

Versatile wet deposition techniques for functional oxide coatings  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Functional oxide coatings are essential components in a variety of today's technical products and developments, but often applications are limited by the low flexibility and the high cost of the vapor phase deposition techniques used at present. Wet chemical processes based on the sol-gel and nanoparticle approaches can provide desired alternatives for a large number of such applications. This is shown for the high temperature sol-gel processing and the low-temperature nanoparticle approach w...

Aegerter, Michel A.; Pu?tz, Jo?rg; Gasparro, Guido; Al-dahoudi, Naji

2004-01-01

46

A study on the adsorption of sea water constituents onto the titanium-activated carbon composite adsorbent by spark source mass spectrometry  

International Nuclear Information System (INIS)

Both before and after adsorption of uranium from sea water, the concentrations of various elements on titanium-activated carbon composite adsorbent were determined by spark source mass spectrometry. From the results, the behaviors of sea water constituents in uranium adsorption process were discussed. Adsorptivity of the adsorbent for sea water constituents was evaluated by concentration factors which were calculated from element concentrations in the adsorbent and sea water. The order of adsorptivity for sea water constituents was as follows: alkali metals, halogens, sulphur < boron, alkaline earth metals < phosphor, arsenic < transition metals, uranium. (author)

1979-01-01

47

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

48

Antibacterial activity of zinc oxide-coated nanoporous alumina  

International Nuclear Information System (INIS)

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

2012-07-25

49

Adsorption characteristics of uranyl ions by manganese oxide coated sand in batch mode  

International Nuclear Information System (INIS)

In this paper, the sorption properties of manganese oxide coated sand (MOCS) towards uranium(VI) from aqueous solutions were studied in a batch adsorption system. Scanning electron microscope (SEM) and infrared (IR) analyses were used to characterize MOCS. Parameters affecting the adsorption of uranium(VI), such as the contact time, salt concentration, competitive ions, temperature and initial uranium(VI) concentration, were investigated. The equilibrium adsorption data were analyzed by Langmuir, Freundlich and Redlich-Peterson models using nonlinear regressive analysis. The results indicated that the Langmuir and Redlich-Peterson models provided the best correlation of experimental data. The kinetic experimental data were analyzed using three kinetic equations including pseudo-first order equation, pseudo-second order equation and intraparticle diffusion model to examine the mechanism of adsorption and potential rate-controlling step. The process mechanism was found to be complex, consisting of both surface adsorption and pore diffusion. The effective diffusion parameter D i values estimated in the order of 10-7 cm2 s-1 indicated that the intraparticle diffusion was not the rate-controlling step. Thermodynamic study showed that the adsorption was a spontaneous, endothermic process. Adsorbed U(VI) ions were desorbed effectively (about 94.7%) by 0.1 mol L-1 HNO3. The results indicated that MOCS can be used as an effective adsorbent for the treatment of industrial wastewaters contaminated with U(VI) ions. (author)

2011-04-01

50

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

51

Fabrication of yttrium oxide and erbium oxide coatings by PVD methods  

International Nuclear Information System (INIS)

The development of insulating coatings is one of the most important subjects in fusion reactor liquid lithium blanket research and development. The compounds aluminum nitride, yttrium oxide and erbium oxide are considered to be candidate materials for ceramic coatings because of their high electrical resistance and their high compatibility with liquid lithium. In the present study, two types of PVD methods were employed for fabrication of coatings, and their properties were examined. Yttrium oxide and erbium oxide coatings were fabricated by means of radio frequency (RF) sputtering, and erbium oxide coatings were fabricated by arc source plasma assisted deposition. The coatings were all close to their stoichimetric composition, and had higher resistances than that required in the fusion reactor (102-104 ?m). The coatings had the crystallinity observed by X-ray diffraction (XRD), which were influenced by fabrication parameters as high frequency electric power or substrate temperature. Annealing after fabrication makes coatings crystallized more while the crystallinity of the coatings fabricated at low temperature were inferior to that of the coatings fabricated at higher temperature

2005-11-01

52

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

53

Synthesis, structural and mechanical characterization of sputtered tungsten oxide coatings  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Tungsten oxide coatings were deposited without substrate bias by DC reactive magnetron sputtering of a tungsten target using oxygen as reactive gas. By tuning the partial pressure of oxygen (pO2/pAr) between 0 and 4, the oxygen content of the films was changed from 0 to 75 at.%. The structure of the films (investigated by X-ray diffraction) depends on their oxygen content. For low oxygen contents, the [alpha]-W and [beta]-W3O phases were observed (< 30 at.%), and with the increase of oxyge...

Parreira, N. M. G.; Carvalho, N. J. M.; Cavaleiro, A.

2006-01-01

54

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

Science.gov (United States)

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

Johnson, Christopher D; Worrall, Fred

2007-06-01

55

Adsorption of Radioactive 134Cs and 60Co ions onto iron oxide coated sand  

International Nuclear Information System (INIS)

Iron oxide coated sand (IOCS) has been prepared with different iron contents. The Fe concentration in the coating solution affects largely the Fe % in the coated layer of the prepared IOCS material. Ions has been used as granular sorbent for134Cs and 60Co radionuclides at tracer concentration levels in aqueous solutions of constant ph value. Effect of different parameters such as ph variation, contact time and 134Cs and 60Co ion concentrations on the adsorption of the radionuclides onto IOCS material have been discussed. At ph 8-10, about 90% of 60Co and 10% of 134Cs were adsorbed onto IOCS from the aqueous solution. The difference in the sorption capability of 134Cs and 60Co onto IOCS has been discussed. Also, the absorption of 60Co ions increases with increasing Fe % in the coated layer from 0.1 to 1.2 Fe % of IOCS material. Desorption % of 60Co ions from IOCS has been reached 95%. Adsorption of Pb(II) reached 95% from initial Pb(II) concentration of 49.0 mg/L, while the adsorption of Zn(II) ions reached 71% from initial Zn(II) concentration of 50.5 mg/L from their aqueous solutions

2003-01-01

56

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

Science.gov (United States)

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

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

2014-06-01

57

Method of forming oxide coatings. [for solar collector heating panels  

Science.gov (United States)

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. (inventor)

1983-01-01

58

Polymer adsorbers  

Energy Technology Data Exchange (ETDEWEB)

While conventional activated carbon and inorganic adsorbers are widely accepted in the chemical industry, the position of macroporous polymer adsorbers is unique with regard to their unusual selectivity and physical properties. Of the many applications of these adsorbers, the following are discussed: Removing chlorinated hydrocarbons from waste water, phenol adsorption on industrial waste water, removing BTX from refinery waste water, pesticide recovery from production waste water, oil recovery from waste water.

Ferraro, J.F.

1987-07-01

59

Laccase Immobilized on a PAN/Adsorbents Composite Nanofibrous Membrane for Catechol Treatment by a Biocatalysis/Adsorption Process  

Directory of Open Access Journals (Sweden)

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

Qingqing Wang

2014-03-01

60

Preparation and properties of cobalt oxides coated carbon fibers as microwave-absorbing materials  

International Nuclear Information System (INIS)

Cobalt oxides/carbon fibers (CoOx/CFs) composites were synthesized by thermal oxidation of cobalt coated carbon fibers (Co/CFs). The scanning electron microscopy images and X-ray diffraction pattern indicate that the layers are about 0.7 ?m and composed of Co3O4 and CoO (CoOx), the preferred condition for preparation of CoOx/CFs composites is to anneal Co/CFs precursors at 350 deg. C for 3 h in air. The coercivity, saturation magnetization and residual magnetization of the CoOx/CFs composites are 464.8 Oe, 10.62 emu/g and 2.21 emu/g, respectively. The reflectivity of cobalt oxides coated carbon fibers (1.11-5.12 mm in thickness) is less than -10 dB over the working frequency range of 4.04-18.00 GHz and less than -20 dB over 11.54-14.77 GHz. The lowest reflectivity is -45.16 dB at 13.41 GHz when the thickness is 1.50 mm.

2011-06-15

 
 
 
 
61

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

International Nuclear Information System (INIS)

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

2011-02-03

62

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

Energy Technology Data Exchange (ETDEWEB)

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

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

2011-02-03

63

Preparation and properties of cobalt oxides coated carbon fibers as microwave-absorbing materials  

Energy Technology Data Exchange (ETDEWEB)

Cobalt oxides/carbon fibers (CoO{sub x}/CFs) composites were synthesized by thermal oxidation of cobalt coated carbon fibers (Co/CFs). The scanning electron microscopy images and X-ray diffraction pattern indicate that the layers are about 0.7 {mu}m and composed of Co{sub 3}O{sub 4} and CoO (CoO{sub x}), the preferred condition for preparation of CoO{sub x}/CFs composites is to anneal Co/CFs precursors at 350 deg. C for 3 h in air. The coercivity, saturation magnetization and residual magnetization of the CoO{sub x}/CFs composites are 464.8 Oe, 10.62 emu/g and 2.21 emu/g, respectively. The reflectivity of cobalt oxides coated carbon fibers (1.11-5.12 mm in thickness) is less than -10 dB over the working frequency range of 4.04-18.00 GHz and less than -20 dB over 11.54-14.77 GHz. The lowest reflectivity is -45.16 dB at 13.41 GHz when the thickness is 1.50 mm.

Liu Ying; Zhang Zhongquan; Xiao Songtao; Qiang Chengwen; Tian Liangliang [Key Laboratory for the Magnetism and Magnetic Materials of the Ministry of Education, Lanzhou University, Lanzhou 730000 (China); Institute of Materials Science and Engineering, Lanzhou University, Lanzhou 730000 (China); Xu Jincheng, E-mail: xuhuan@lzu.edu.cn [Key Laboratory for the Magnetism and Magnetic Materials of the Ministry of Education, Lanzhou University, Lanzhou 730000 (China); Institute of Materials Science and Engineering, Lanzhou University, Lanzhou 730000 (China)

2011-06-15

64

Surface Behavior in Deuterium Permeation through Erbium Oxide Coating  

International Nuclear Information System (INIS)

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

2010-10-01

65

A highly efficient carboxyl-terminated hybrid adsorbent composite matrix for the adsorption of uranium (VI) and thorium(IV) from aqueous solutions and nuclear industry effluents  

International Nuclear Information System (INIS)

A novel hybrid adsorbent composite matrix, polymethacrylic acid-grafted chitosan/bentonite (PMAA-g-CTS/B) was prepared through graft copolymerization reaction of methacrylic acid and chitosan in the presence of bentonite and N,N'-methylene-bisacrylamide as cross linker. The composite was characterized using FTIR, XRD, surface area analyzer and Zeta potential measurements. The adsorption behavior of the composite towards U(VI) and Th(IV) from water, and simulated nuclear industry wastewater was studied using batch process. Adsorption-desorption experiments over four cycles illustrate the feasibility of the repeated uses of this composite for the extraction of U(VI) and Th(IV) from aqueous solutions. Kinetic and isotherm studies showed that the composite exhibit high adsorption capacity for U(VI) as well as Th(IV) ions. (author)

2010-03-01

66

XPS characterisation of plasma treated and zinc oxide coated PET  

International Nuclear Information System (INIS)

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

2009-02-15

67

Transformation of bisphenol A by manganese oxide-coated sand.  

Science.gov (United States)

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

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

2013-03-01

68

Inorganic adsorbents  

International Nuclear Information System (INIS)

Purpose: To enable selective and efficient removal of transition element such as cobalt from high-temperature water such as reactor water. Constitution: Porous titanium metal and water are filled in an autoclave. After tightly closing the autoclave, heating treatment is applied, by which the surface of the porous titanium metal is converted into titanium oxide. After washing the oxide with water and then drying, adsorbents can be obtained. When the adsorbents are filled in a reactor-water purifier and brought into direct contact with the reactor-water at high-tenperature, the adsorbents adsorb metal ions in the high-temperature water. Accordingly, since there is no requirement for cooling the reactor-water, metals ions can be removed with no heat loss. In addition, the amount of radioactivity in the reactor can be decreased. (Kawakami, Y.)

1983-11-25

69

Mechanism of formation of humus coatings on mineral surfaces 3. Composition of adsorbed organic acids from compost leachate on alumina by solid-state 13C NMR  

Science.gov (United States)

The adsorption of compost leachate DOC on alumina is used as a model for elucidation of the mechanism of formation of natural organic coatings on hydrous metal oxide surfaces in soils and sediments. Compost leachate DOC is composed mainly of organic acid molecules. The solid-state 13C NMR spectra of these organic acids indicate that they are very similar in composition to aquatic humic substances. Changes in the solid-state 13C NMR spectra of compost leachate DOC fractions adsorbed on alumina indicate that the DOC molecules are most likely adsorbed on metal oxide surfaces through a combination of polar and hydrophobic interaction mechanisms. This combination of polar and hydrophobic mechanism leads to the formation of bilayer coatings of the leachate molecules on the oxide surfaces.

Wershaw, R. L.; Llaguno, E. C.; Leenheer, J. A.

1996-01-01

70

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

Directory of Open Access Journals (Sweden)

Full Text Available 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.

M. Ashraful Alam

2008-01-01

71

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

72

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

Directory of Open Access Journals (Sweden)

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

Velmurugan Thavasi

2009-01-01

73

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

Science.gov (United States)

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

Jiang, Liping; Liu, Peng

2014-07-15

74

Manganese oxide-coated redox bars as an indicator for reducing soil conditions  

Science.gov (United States)

Field identification of reducing soil conditions is of concern not only for soil pedogenesis but also for nutrient and pollutant dynamics in soils. We manufactured manganese (Mn) oxide-coated polyvinyl chloride (PVC) bars and proved their suitability for identification of reducing soil conditions in both the laboratory and field. Birnessite (?-MnO2) was synthesized according to a recently published method and was coated onto white PVC bars. We used microcosm devices with adjusted redox potentials (EH) to distinguish the onset and intensity of depletion patterns along the Mn oxide-coating and soil column experiments combined with field application to validate the enhanced removal of Mn against Fe oxide-coated bars under anaerobe soil conditions. Field application was performed at a site with shallow and strongly fluctuating water tables where water table depth and soil temperature were monitored. Three microcosm experiments adjusted to oxidizing (EH ~500 mV, pH 7), weakly reducing (EH ~175 mV, pH 7) and moderately reducing conditions (EH ~25 mV, pH 7) showed depending on the EH no, slight, or intense removal of the Mn oxide-coating, respectively. Moreover, the removal of Mn oxide (225 mm2 d-1) in soil column experiments exceeded the removal of Fe oxide (118 mm2 d-1). The enhanced removal of the Mn oxide-coating was also found under anaerobe conditions in field application. Consequently, identifying of reducing conditions in soils by Mn oxide-coated bars is possible. We recommend using this methodology for short-term monitoring, e.g. on weekly basis, since tri- and tetravalent Mn is the preferred electron acceptor compared with trivalent Fe.

Dorau, Kristof; Mansfeldt, Tim

2014-05-01

75

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

76

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

77

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

78

Study of the formation and self-lubrication mechanisms of boric acid films on boric oxide coatings.  

Science.gov (United States)

An investigation was made of the formation and self-lubrication mechanisms of boric acid films on boric oxide coatings prepared by vacuum evaporation. Measured friction coefficients of a steel ball sliding on a boric-oxide-coated-steel disk and a sapphire...

A. Erdemir G. R. Fenske R. A. Erck

1990-01-01

79

Zero-valent iron and iron oxide-coated sand as a combination for removal of co-present chromate and arsenate from groundwater with humic acid  

International Nuclear Information System (INIS)

The combination of zero-valent iron (Fe0) and iron oxide-coated sand (IOCS) was used to remove Cr(VI) and As(V) from groundwater in this study. The efficiency and the removal mechanism of Cr(VI) and As(V) by using this combination, with the influence of humic acid (HA), were investigated using batch experiments. Results showed that, compared to using Fe0 or IOCS alone, the Fe0-IOCS can perform better on the removal of both Cr(VI) and As(V). Metal extraction studies showed that As(V) was mainly removed by IOCS and iron corrosion products while Cr(VI) was mainly removed by Fe0 and its corrosion products. Competition was found between Cr(VI) and As(V) for the adsorption sites on the iron corrosion products. HA had shown insignificant effects on Cr(VI) removal but some effects on As(V) removal kinetics. As(V) was adsorbed on IOCS at the earlier stage, but adsorbed/coprecipitated with the iron corrosion products at the later stage. - Research Highlights: ? Fe0-IOCS is better reactive media for removing Cr(VI) and As(V) from groundwater. ? As(V) was mainly removed by the IOCS and the iron corrosion products. ? Cr(VI) was mainly removed by Fe0 and its corrosion products. ? As(V) adsorption was inhibited in the presence of HA, when using Fe0 alone. ? IOCS can provide the adsorption sites for As(V) that complement the weakness of Fe0. - Chromate and arsenate-contaminated groundwater can be better treated by using combination of zero-valent iron and iron oxide-coated sand.

2011-02-01

80

Zero-valent iron and iron oxide-coated sand as a combination for removal of co-present chromate and arsenate from groundwater with humic acid  

Energy Technology Data Exchange (ETDEWEB)

The combination of zero-valent iron (Fe{sup 0}) and iron oxide-coated sand (IOCS) was used to remove Cr(VI) and As(V) from groundwater in this study. The efficiency and the removal mechanism of Cr(VI) and As(V) by using this combination, with the influence of humic acid (HA), were investigated using batch experiments. Results showed that, compared to using Fe{sup 0} or IOCS alone, the Fe{sup 0}-IOCS can perform better on the removal of both Cr(VI) and As(V). Metal extraction studies showed that As(V) was mainly removed by IOCS and iron corrosion products while Cr(VI) was mainly removed by Fe{sup 0} and its corrosion products. Competition was found between Cr(VI) and As(V) for the adsorption sites on the iron corrosion products. HA had shown insignificant effects on Cr(VI) removal but some effects on As(V) removal kinetics. As(V) was adsorbed on IOCS at the earlier stage, but adsorbed/coprecipitated with the iron corrosion products at the later stage. - Research Highlights: Fe{sup 0}-IOCS is better reactive media for removing Cr(VI) and As(V) from groundwater. As(V) was mainly removed by the IOCS and the iron corrosion products. Cr(VI) was mainly removed by Fe{sup 0} and its corrosion products. As(V) adsorption was inhibited in the presence of HA, when using Fe{sup 0} alone. IOCS can provide the adsorption sites for As(V) that complement the weakness of Fe{sup 0}. - Chromate and arsenate-contaminated groundwater can be better treated by using combination of zero-valent iron and iron oxide-coated sand.

Mak, Mark S.H.; Rao, Pinhua [Department of Civil and Environmental Engineering, Hong Kong University of Science and Technology (Hong Kong); Lo, Irene M.C., E-mail: cemclo@ust.h [Department of Civil and Environmental Engineering, Hong Kong University of Science and Technology (Hong Kong)

2011-02-15

 
 
 
 
81

Adsorber fires  

International Nuclear Information System (INIS)

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

1987-05-01

82

Studies on yttrium oxide coatings for corrosion protection against molten uranium  

International Nuclear Information System (INIS)

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

2012-12-01

83

Adsorber fires  

International Nuclear Information System (INIS)

The following conclusions are offered with respect to activated charcoal filter systems in nuclear power plants: (1) The use of activated charcoal in nuclear facilities presents a potential for deep-seated fires. (2) The defense-in-depth approach to nuclear fire safety requires that if an ignition should occur, fires must be detected quickly and subsequently suppressed. (3) Deep-seated fires in charcoal beds are difficult to extinguish. (4) Automatic water sprays can be used to extinguish fires rapidly and reliably when properly introduced into the burning medium. The second part of the conclusions offered are more like challenges: (1) The problem associated with inadvertent actuations of fire protection systems is not a major one, and it can be reduced further by proper design review, installation, testing, and maintenance. Eliminating automatic fire extinguishing systems for the protection of charcoal adsorbers is not justified. (2) Removal of automatic fire protection systems due to fear of inadvertent fire protection system operation is a case of treating the effect rather than the cause. On the other hand, properly maintaining automatic fire protection systems will preserve the risk of fire loss at acceptable levels while at the same time reducing the risk of damage presented by inadvertent operation of fire protection systems

1987-05-01

84

Efficient and versatile fibrous adsorbent based on magnetic amphiphilic composites of chrysotile/carbon nanostructures for the removal of ethynilestradiol.  

Science.gov (United States)

In this work, chrysotile was used as support to grow carbon nanotubes and nanofibers to produce fibrous amphiphilic magnetic nanostructured composites. Iron impregnated on the chrysotile surface at 1, 5 and 15 wt% was used as catalyst to grow carbon nanostructures by CVD (chemical vapor deposition) with ethanol at 800°C. Raman, TG/DTA, Mössbauer, XRD, BET, SEM, TEM, elemental analyses and contact angle measurements suggested the formation of a complex amphiphilic material containing up to 21% of nanostructured hydrophobic carbon supported on hydrophilic Mg silicate fibers with magnetic Fe cores protected by carbon coating. Adsorption tests for the hormone ethynilestradiol (EE), a hazardous water contaminant, showed remarkable adsorption capacities even compared to high surface area activated carbon and multiwall carbon nanotubes. These results are discussed in terms of the hydrophobic surface of the carbon nanotubes and nanofibers completely exposed and accessible for the adsorption of the EE molecules combined with the hydrophilic Mg silicate surface which allows good dispersion in water. The composites are magnetic and after adsorption the dispersed particles can be removed by a simple magnetic process. Moreover, the fibrous composites can be conformed as threads, screens and pellets to produce different filtering media. PMID:23399907

Teixeira, Ana Paula C; Purceno, Aluir D; de Paula, Camila C A; da Silva, Julio César C; Ardisson, José D; Lago, Rochel M

2013-03-15

85

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

Science.gov (United States)

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

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

2014-05-01

86

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

Digital Repository Infrastructure Vision for European Research (DRIVER)

Adsorption and desorption mechanisms of methylene blue (MB) removal with iron-oxide coated porous ce-ramics filter (IOCPCF) were investigated in batch and column mode. The results revealed that MB removal mechanisms included physical adsorption and chemical adsorption, of which chemical adsorption by surface ligand complex reaction played a dominant role after infrared spectrum analysis. Recycling agents were se-lected from dilute nitric acid (pH=3), sodium hydroxide solution (pH=12) and dist...

Li, Fangwen; Wu, Xiaoai; Ma, Songjiang; Xu, Zhongjian; Liu, Wenhua; Liu, Fen

2009-01-01

87

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

Digital Repository Infrastructure Vision for European Research (DRIVER)

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

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

2012-01-01

88

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

Digital Repository Infrastructure Vision for European Research (DRIVER)

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

2008-01-01

89

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

Digital Repository Infrastructure Vision for European Research (DRIVER)

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 ob...

2012-01-01

90

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

Science.gov (United States)

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

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

2013-10-01

91

Mechanical analysis of ultrathin oxide coatings on polymer substrates in situ in a scanning electron microscope  

International Nuclear Information System (INIS)

Uniaxial fragmentation tests were carried out in situ in a scanning electron microscope (SEM) on 10-nm-thick silicon oxide coatings deposited by plasma enhanced chemical vapor deposition on poly(ethylene terephthalate). In order to prevent charging effects due to the isolating nature of the oxide surface, an additional conductive gold layer was sputtered onto the coating prior to its tensile loading in the SEM chamber. The gold layer was shown not to affect initiation of tensile failure of the oxide coating, and was used to achieve optimal resolution by eliminating charging effects in the low-strain range. In contrast, in the high strain range, the failure behavior of the oxide coating was found to be modified by the gold layer. It was nevertheless possible to analyze the damage mechanisms of the thin coating without a gold layer due to sufficient crack opening. The coating cohesive strength was found to be equal to 5.1 GPa, and the coating/polymer interfacial strength was found to be equal to 84 MPa using a Weibull size-dependent probability of failure for the oxide, and assuming a perfectly plastic stress transfer between the different layers

2003-08-01

92

Aluminum oxide coating for post-growth photo emission wavelength tuning of indium phosphide nanowire networks  

Science.gov (United States)

Semiconductor-oxide nanostructure devices can be a very intriguing material platform if optoelectronic properties of the original semiconductor nanostructures can be tuned by explicitly controlling properties of the oxide coating. This paper describes our finding that optical properties of semiconductor nanowires can be tuned by depositing a thin layer of metal oxide. In this experiment, indium phosphide nanowires were grown by metal organic chemical vapor deposition on silicon substrates with gold catalyst. The nanowires formed three-dimensional nanowire networks from which collective optical properties were obtained. The nanowire network was coated with an aluminum oxide thin film deposited by plasma-enhanced atomic layer deposition. We studied the dependence of the peak wavelength of photoluminescence spectra on the thickness of the oxide coatings. We observed continuous blue shift in photoluminescence spectra when the thickness of the oxide coating was increased. The observed blue shift is attributed to the Burstein-Moss effect due to increased carrier concentration in the nanowire cores caused by repulsion from an intrinsic negative fixed charge from the oxide surface. Samples were further characterized by scanning electron microscopy, transmission electron microscopy, and selective area diffractometry in an attempt to explain the physical mechanisms for the blue shift.

Fryauf, David M.; Zhang, Junce; Norris, Kate J.; Diaz Leon, Juan; Kobayashi, Nobuhiko P.

2013-09-01

93

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.

Daniel L. Alge

2012-05-01

94

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.

Fernandes Stela Maria de Carvalho

2004-01-01

95

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

Scientific Electronic Library Online (English)

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

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

96

Cavitation erosion resistance of microarc oxidation coating on aluminium alloy  

Science.gov (United States)

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

Cheng, Feng; Jiang, Shuyun; Liang, Jun

2013-09-01

97

Chemical synthesis and characterization of manganese oxide coated Ni particles  

Science.gov (United States)

Nanosized Ni particles with an average diameter of about 8 nm were prepared by reducing of NiCl2 with sodium borohydride (NaBH4) in aqueous solution. By moderate annealing in protective atmosphere, the composite grew up to be 15-20 nm particles. Both of the as-prepared and annealed Ni particles were coated by a layer of manganese oxide via decomposition reaction in aqueous KMnO4 solution. Hysteresis loops of as-prepared samples show a large increase in the magnetization with decreasing temperature and an unsaturated component at high magnetic field. In contrast, the ferromagnetic characteristics of annealed one are much stronger with large magnetization and coercivity. The thermomagnetic curves verified the coexistence of ferromagnetic Ni and antiferromangetic Mn oxide phases. But there exists no exchange bias behavior in the samples, even though the interface structure between the ferromagnetic Ni core and the antiferromagnetic manganese oxides has been distinctly formed. The absence of exchange bias probably originates from the weak ferromagnetic characteristic of Ni cores.

An, Jing; Xu, LiHong; He, Jun; Zhao, DongLiang; Liu, ZhongYuan

2013-08-01

98

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

International Nuclear Information System (INIS)

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

99

Improving endothelial cell adhesion and proliferation on titanium by sol-gel derived oxide coating.  

Science.gov (United States)

In-stent restenosis becomes increasingly prevalent as a difficult-to-treat disease. An alternative therapeutic strategy is enhancing endothelialization on metallic stent surfaces. This study attempted to modify surface chemistry and topography of commercial pure titanium (cp-Ti) by different sol-gel derived oxide coatings (TiO(2), SiO(2), SiO(2)/TiO(2), and Nb(2)O(5)) to improve endothelialization. The physiochemical properties of the modified surfaces were characterized by ellipsometry, atomic force microscope, and sessile-drop method. The cell adhesion/proliferation quantity, cell adhesion morphology, and focal adhesion protein expression were evaluated with human pulmonary microvascular endothelial cell line. The thickness of oxide coatings approximates to 100 nm; significantly rougher nanoporous structure was found in the TiO(2) and Nb(2)O(5) coatings than that of cp-Ti. SiO(2) coating possesses the highest surface energy (75.1 mJ/m(2)) and the lowest was for cp-Ti (45.7 mJ/m(2)). TiO(2) coating showed significantly higher endothelial cell adhesion rate than others; TiO(2), Nb(2)O(5), and TiO(2)/SiO(2) coatings exhibited higher endothelial proliferation in 3-day assays than noncoated Ti. In hemocompatible test, they also showed good hemocompatibility. These results offer the insight into that certain oxide coatings on titanium could significantly improve endothelial cell adhesion and proliferation especially in early period, which will favor reaching the endothelialization rapidly and suitable as matrix for "endothelial seeding" stent. PMID:19274713

Chai, Feng; Ochsenbein, Anne; Traisnel, Michel; Busch, Ralf; Breme, Jürgen; Hildebrand, Hartmut F

2010-02-01

100

Synthesis, corrosion and wear of anodic oxide coatings on Ti-6Al-4V.  

Science.gov (United States)

Electrodeposited anodic oxide coatings were produced on Ti-6Al-4V substrates using aqueous electrolytes containing dissolved calcium and phosphorus. Different coatings were produced by varying the time periods. The coatings were characterised by XRD technique and TEM. The coatings were exposed to Simulated Body Fluid (SBF). Electrochemical polarisation and ac impedance studies too were performed on the coatings in SBF. Pins were coated and run against wooden disc in pin-on-disc type of wear tests. Coatings produced from long time electrolysis showed very good resistance to the attack of SBF and less wear compared to those produced from short time exposure. PMID:17143733

Narayanan, R; Mukherjee, Partho; Seshadri, S K

2007-05-01

 
 
 
 
101

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

Directory of Open Access Journals (Sweden)

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

Lanza Marcos Roberto V.

2002-01-01

102

A review of adsorbents and adsorbates in solid-vapour adsorption heat pump systems  

Energy Technology Data Exchange (ETDEWEB)

Worldwide efforts to use solid-vapour adsorption technology for heat pumps, have been intensified since the imposition of international restrictions on production and use of chlorofluorocarbons. Promising recent developments in Japan, Europe and USA, include the use of porous metal hydrides and composite adsorbents. A review of adsorbents and adsorbates use in various investigations on solid-vapour adsorption heat pump are presented in this paper, with an aim of initiating a novel concept experimental investigation. (author)

Srivastava, N.C.; Eames, I.W. [Nottingham Univ., Inst. of Building Technology, Nottingham (United Kingdom)

1997-08-01

103

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

2007-12-01

104

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

DEFF Research Database (Denmark)

Sorption to iron-oxide coated sand (IOCS) is a promosing technology for removal of the dissolved heavy metal fraction in stormwater runoff. The development of a new technology is necessary since studies of stormwater runoff from traffic areas indicate that an oil separator and detention pond may not guarantee that emission limit values set by the Danish EPA are satisfied. Runoff water was sampled from an urban highway, allowed to settle for 24 hours to simulate the effect of a detention pond, and finally spiked with metals to ensure concentration levels similar to high levels reported in the leterature (Pb=20, Cu=40, Zn=110, and Cr=15 ppb). Column experiments were conducted to test the influence of the infiltration rate (1 or 3 m/h) and the type of iron(hydr)oxide mineral (amorphous ferrihydrite and goethite coated sand). The results show that at least 90% of lead, copper and zinc can be removed by IOCS after 480 pore volumes. Control columns with uncoated filter sand show that lead, copper and zinc were removed with >95%, 35% and 5%, respectively. The removal of the negative metaloxy-ion, CrO4-3 was insignificant in both IOCS and sand columns at pH=7.7. Destruction of the columns after the experiments showed, that Pb, Cu and Zn penetrated to different depths in the columns. No saturation of lead was found in the first cm of the column after 1696 pore volumes of teated water. Copper showed a curved adsorption front, indicating that an infiltration speed of 3 m/h is sligtly too fast for the equilibrium between water phase and IOCS to be reached. The column with ferrihydrite was fully saturated with regard to zinc after 1696 pore volumes. In general the coating of goethite is found to be at least twice as effective as ferrihydrite with respect to the adsorption capacity of copper and zinc. Furthermore, desorption of metals from the IOCS by soaking in weak acid (pH=2.25) showed that 20%, 58% and 75% of the adsorbed Pb, Cu and Zn was recovered. Reuse of the IOCS after soaking in weak acis is possible, but it is likely to lower the adsorption capacities found in this study.

Møller, J.; Ledin, Anna

2002-01-01

105

Mn oxide coated catalytic membranes for a hybrid ozonation-membrane filtration: comparison of Ti, Fe and Mn oxide coated membranes for water quality.  

Science.gov (United States)

In this study the performance of catalytic membranes in a hybrid ozonation-ceramic membrane filtration system was investigated. The catalytic membranes were produced by coating commercial ceramic ultrafiltration membranes with manganese or iron oxide nanoparticles using a layer-by-layer self-assembly technique. A commercial membrane with a titanium oxide filtration layer was also evaluated. The performance of the coated and uncoated membranes was evaluated using water from a borderline eutrophic lake. The permeate flux and removal of the organic matter was found to depend on the type of the metal oxide present on the membrane surface. The performance of the manganese oxide coated membrane was superior to that of the other membranes tested, showing the fastest recovery in permeate flux when ozone was applied and the greatest reduction in the total organic carbon (TOC) in the permeate. The removal of trihalomethanes (THMs) and haloacetic acids (HAAs) precursors using the membrane coated 20 times with manganese oxide nanoparticles was significantly better than that for the membranes coated with 30 or 40 times with manganese oxide nanoparticles or 40 times with iron oxide nanoparticles. PMID:20822791

Byun, S; Davies, S H; Alpatova, A L; Corneal, L M; Baumann, M J; Tarabara, V V; Masten, S J

2011-01-01

106

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.

2011-07-01

107

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

Energy Technology Data Exchange (ETDEWEB)

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 {mu}g of adsorbed SRHA occupied 9.28 {+-} 0.03 x 10{sup 9} sites at pH7.6 and IS of 1.6 mMol but covered 2.75 {+-} 0.2 x 10{sup 9} 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.

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

2011-07-15

108

Properties of adsorbents composed of hydrous aluminum oxide, and its selective adsorption of lithium from sea water  

International Nuclear Information System (INIS)

Three types of adsorbents, hydrous aluminum oxide, composite of active carbon and hydrous aluminum oxide, and manganese dioxide added hydrous aluminum oxide, were prepared as adsorbents of lithium from sea water. Suppression of crystallization of hydrous aluminum oxide was observed in the composite adsorbent and manganese oxide added adsorbent. Of all the adsorbents prepared, amorphous ones adsorbed lithium ion selectively from lithium enriched sea water. (author)

1978-01-01

109

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

Directory of Open Access Journals (Sweden)

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

Songjiang MA

2009-05-01

110

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

CERN Multimedia

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

111

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

International Nuclear Information System (INIS)

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

112

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

Science.gov (United States)

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

113

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

Directory of Open Access Journals (Sweden)

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

Nie Yining

2010-09-01

114

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

International Nuclear Information System (INIS)

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

2013-02-15

115

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

116

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

International Nuclear Information System (INIS)

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

2005-07-22

117

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

Scientific Electronic Library Online (English)

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

Lanza, Marcos Roberto V.; Bertazzoli, Rodnei.

118

Nanostructured hydrophobic DC sputtered inorganic oxide coating for outdoor glass insulators  

Science.gov (United States)

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

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

2014-03-01

119

Annealing effects on microstructure and mechanical properties of chromium oxide coatings  

Energy Technology Data Exchange (ETDEWEB)

Reactive radio frequency magnetron sputter-deposited chromium oxide coatings were annealed at different temperatures and times. The influence of annealing temperature on the microstructure, surface morphology and mechanical properties was examined by X-ray diffraction, nanoindentation, pin-on-disc wear and scratch tests, respectively. X-ray results show that the chromium oxide sputtered at room temperature in low oxygen flux is primarily amorphous. Annealing below 400 deg. C did not cause much change, while annealing at higher temperature of 500 deg. C caused a significant change in microstructure and mechanical properties. Hardness increased from 12.3 GPa to 26 GPa, and the wearability improved with higher annealing temperature due to the formation of crystalline Cr{sub 2}O{sub 3} phase, which occurs at 470 deg. C. Annealing time had little effect on mechanical properties and microstructure, although coating surface roughness increased with a longer annealing time. Coating adhesion was improved by annealing, due to residual stress relief and possible interfacial interdiffusion.

Pang Xiaolu [Department of Materials Physics and Chemistry, University of Science and Technology Beijing, Beijing 100083 (China); Department of Mechanical Engineering, University of South Florida, Tampa, FL 33620 (United States); Gao Kewei [Department of Materials Physics and Chemistry, University of Science and Technology Beijing, Beijing 100083 (China)], E-mail: kwgao@yahoo.com; Luo Fei; Yang Huisheng; Qiao Lijie; Wang Yanbin [Department of Materials Physics and Chemistry, University of Science and Technology Beijing, Beijing 100083 (China); Volinsky, Alex A. [Department of Mechanical Engineering, University of South Florida, Tampa, FL 33620 (United States)

2008-06-02

120

Annealing effects on microstructure and mechanical properties of chromium oxide coatings  

International Nuclear Information System (INIS)

Reactive radio frequency magnetron sputter-deposited chromium oxide coatings were annealed at different temperatures and times. The influence of annealing temperature on the microstructure, surface morphology and mechanical properties was examined by X-ray diffraction, nanoindentation, pin-on-disc wear and scratch tests, respectively. X-ray results show that the chromium oxide sputtered at room temperature in low oxygen flux is primarily amorphous. Annealing below 400 deg. C did not cause much change, while annealing at higher temperature of 500 deg. C caused a significant change in microstructure and mechanical properties. Hardness increased from 12.3 GPa to 26 GPa, and the wearability improved with higher annealing temperature due to the formation of crystalline Cr2O3 phase, which occurs at 470 deg. C. Annealing time had little effect on mechanical properties and microstructure, although coating surface roughness increased with a longer annealing time. Coating adhesion was improved by annealing, due to residual stress relief and possible interfacial interdiffusion

2008-06-02

 
 
 
 
121

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

Energy Technology Data Exchange (ETDEWEB)

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

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

2012-03-30

122

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

123

Molecular Adsorber Coating  

Science.gov (United States)

A document discusses a zeolite-based sprayable molecular adsorber coating that has been developed to alleviate the size and weight issues of current ceramic puck-based technology, while providing a configuration that more projects can use to protect against degradation from outgassed materials within a spacecraft, particularly contamination-sensitive instruments. This coating system demonstrates five times the adsorption capacity of previously developed adsorber coating slurries. The molecular adsorber formulation was developed and refined, and a procedure for spray application was developed. Samples were spray-coated and tested for capacity, thermal optical/radiative properties, coating adhesion, and thermal cycling. Work performed during this study indicates that the molecular adsorber formulation can be applied to aluminum, stainless steel, or other metal substrates that can accept silicate-based coatings. The coating can also function as a thermal- control coating. This adsorber will dramatically reduce the mass and volume restrictions, and is less expensive than the currently used molecular adsorber puck design.

Straka, Sharon; Peters, Wanda; Hasegawa, Mark; Hedgeland, Randy; Petro, John; Novo-Gradac, Kevin; Wong, Alfred; Triolo, Jack; Miller, Cory

2011-01-01

124

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 (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. PMID:23764573

Cui, Xiaojun; Choo, Kwang-Ho

2013-09-01

125

Regenerative adsorbent heat pump  

Science.gov (United States)

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

Jones, Jack A. (Inventor)

1991-01-01

126

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

127

Extraction of uranium from seawater using magnetic adsorbents  

International Nuclear Information System (INIS)

A new process for the extraction of uranium from seawater was developed. In the process, uranium adsorption is effected using powdered magnetic adsorbents; the adsorbents are then separated from seawater using magnetic separation technology. This process is superior to a column method using a granulated hydrous titanium oxide adsorber bed in the following ways: (1) a higher rate of adsorption is realized because smaller particles are used in the uranium adsorption; and (2) blocking, which is inevitable in an adsorber bed, is eliminated. The composite hydrous titanium-iron oxide as a magnetic adsorbent having high uranium adsorption capacity and magnetization can be prepared by adding urea to a mixed solution of titanium sulfate and ferrous sulfate. Adsorption and desoprtion of uranium and the removal of the adsorbent using a small-scale uranium extraction plant (about 15 m"3/d) is reported, and the feasibility of uranium extraction from seawater by this process is demonstrated. 10 figures

1981-05-08

128

Ionogenic adsorbents based on local raw materials for radiation protection  

International Nuclear Information System (INIS)

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

2012-11-20

129

High temperature cobalt adsorbents  

International Nuclear Information System (INIS)

Purpose: To enable to absorb radioactive corrosion products in reactor water even in high temperature and high pressure water, thereby simplify the device and decrease the heat loss. Constitution: Adsorbents comprising from 50 to 70 w/o of Fe or Ni, from 30 to 50 w/o of Ti and from 0 to 5 w/o Li as the ingredient ratio are used in a reactor water clean up facility for removing radioactive corrosion products, particularly, cobalt ions from primary coolant circuits of a nuclear reactor. The use of the adsorbents under higher temperature and pressure than those for ion exchange resins employed so far is enabled by using such a ingredient ratio, by which the degradation in the adsorbing performance and release of once adsorbed impurities are eliminated. Accordingly, a facility for cleaning up the reactor water after once lowered to ambient temperature and normal pressure and then returning into the primary circuits after increasing to higher temperature and pressure is no more required. (Sekiya, K.)

1984-06-26

130

Effect of the oxide loading on the surface characteristics of LaNio3 oxide coated electrodes  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The LaNiO3 perovskite-type oxide is one of the most tested anode for the oxygen evolution reaction in alkaline solutions. It is well established that the oxide preparation conditions and the electrode fabrication are key factors to control the electrochemical behaviour of oxide coatings. In a previous work the authors studied the influence of preparation conditions of the oxide and support type on the electrochemical behaviour of Ni foam coated LaNiO3 electrodes. Ni foam was selected as suppo...

2011-01-01

131

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

Science.gov (United States)

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

Stenzel, Olaf

2014-02-01

132

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

Digital Repository Infrastructure Vision for European Research (DRIVER)

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...

2008-01-01

133

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

Directory of Open Access Journals (Sweden)

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

Yi Liu

2013-05-01

134

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

Scientific Electronic Library Online (English)

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

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

135

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

136

Characterization of hafnium oxide coatings on low activation martensitic steel at various O2/Ar flow ratios  

International Nuclear Information System (INIS)

Hafnium oxide coatings were prepared at various O2/Ar flow ratios by RF (radio frequency) magnetron sputtering on low activation Martensitic steel. The effects of O2/Ar flow ratio on the deposition rate and the properties of HfO2 are studied. The results show that the deposition rate decreases with increasing the O2/Ar flow ratio. Moreover, the coatings prepared at various O2/Ar flow ratios are compact and the main phase of the coatings is monoclinic. Additionally the coatings prepared at the O2/Ar ratios 0.7 and 1.2 were broken down under 1 MV/cm and show poor electrical insulation properties, while the coatings prepared at smaller O2/Ar flow ratios show better electrical insulation properties. (authors)

2009-07-01

137

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

Energy Technology Data Exchange (ETDEWEB)

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

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

2009-05-15

138

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

139

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 < 0.97). (author)

2012-05-01

140

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

Science.gov (United States)

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

Zhang, W. L.; Choi, H. J.

2014-05-01

 
 
 
 
141

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

International Nuclear Information System (INIS)

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

2008-04-01

142

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

Energy Technology Data Exchange (ETDEWEB)

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

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

2012-12-15

143

Structure and Dynamics of Adsorbed Polymer  

Science.gov (United States)

We study the time dependent composition and structure of macromolecules physisorbed from solution to a single solid surface. Measurements of the surface excess, segmental orientation, bound fraction, segment-surface interaction enthalpy, and adsorption-desorption kinetics were made using Fourier transform infrared spectroscopy in the mode of attenuated total reflection. The polymers were amorphous, linear and flexible. The work described focusses on three areas: (i) time scales of equilibration as an adsorbed molecule relaxes towards its lowest energy configuration, (ii) the specific conformational structure of the chains composing the layer, and (iii) the dependence of equilibrium conditions on the presence of solvent flow past the layer. In order to approach these questions quantitatively, it was first necessary to characterize our experimental system. This was done through studies of competitive adsorption of the polymers employed in the study, and through careful analysis of the oxidized substrate. We find that the classical description of polymer adsorption, based on free energy considerations, is quite limited in its range of applicability. In a weakly adsorbing system, polystyrene adsorbing from dilute cyclohexane onto silicon oxide, rearrangements in the direction of conformational equilibrium were remarkably slow. The time scales of equilibration increased exponentially with length of adsorbed chains. In a more tenaciously bound system, polymethyl -methacrylate in dilute carbon tetrachloride, relaxations were prohibited by steric impedance and segment-surface interactions. The layer was frozen in a nonequilibrium state. For this system, a distribution of conformations was constructed, showing that the earliest arriving molecules were bound in flattened conformations, while the later chains retained their solution-like isotropy. Finally, preliminary evidence of shear induced alignment is presented. The significance is to demonstrate the crippling restriction of present descriptions of adsorption properties to idealized quiescent interfacial environments.

Frantz, Peter Paul

144

Plasma electrolytic oxidation coatings on ?TiAl alloy for potential biomedical applications.  

Science.gov (United States)

In an attempt to enhance the potential of gamma titanium aluminide intermetallic alloy as a biomaterial, its surface characteristics were successfully modified using a calcium and phosphorous rich electrolyte through the application of plasma electrolytic oxidation. Scanning electron microscopy and atomic force microscopy were used to characterize the morphology and topographical features of the resulting coating while X-ray diffraction and energy dispersive spectroscopy were used to determine the surface oxide composition. The mechanical properties of the surface coating were characterized by nanoindentation studies. The results observed show the formation of a submicron scale porous structure and a concomitant increase in the surface roughness. The surface oxide was composed of rutile and anatase phases. Composition gradients of Ca and P were also present which can possibly enhance the biomaterial application potential of this treated surface. Nanoindentation measurements indicate the formation of a fairly compact oxide during the process. © 2013 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 102B: 988-1001, 2014. PMID:24259371

Lara Rodriguez, L; Sundaram, P A; Rosim-Fachini, E; Padovani, A M; Diffoot-Carlo, N

2014-07-01

145

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

Science.gov (United States)

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

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

2010-01-01

146

Method of processing inorganic adsorbents  

International Nuclear Information System (INIS)

Purpose: To greatly decrease the volume of spent inorganic adsorbents with ease while preventing the scattering of radioactive materials, and convert them into a state suitable to disposal. Method: Titanium type spent inorganic adsorbents are supplied to a reactor and, after evacuation, hydrogen is supplied to the inside of the reactor. At the same time, the inside of the reactor is heated by a heater to hydrogenate the inorganic adsorbents. After the hydrogenation, hydrogen is discharged to reduce the pressure inside the reactor. After the completion of the hydrogen removal, the powder of the inorganic adsorbents deposited at the bottom of the reactor is supplied to a compression molding device to form the powder into compression molding products. (Yoshino, Y.)

1984-03-28

147

Preparation of metal adsorbents from chitin/chitosan by radiation technology  

International Nuclear Information System (INIS)

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

2004-08-01

148

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

International Nuclear Information System (INIS)

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

2006-07-25

149

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

Energy Technology Data Exchange (ETDEWEB)

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

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

2006-07-25

150

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

International Nuclear Information System (INIS)

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

2006-07-28

151

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

Science.gov (United States)

A method for removal of iron and arsenic (III) from contaminated water using iron oxide-coated sand and limestone has been developed for drinking water. For the intended use, sand was coated with ferric chloride and used as filtering media. Limestone was added onto the coated sand and the effect of limestone addition on removal efficiency of iron and arsenic was monitored. Both batch and column experiments were conducted to investigate the efficiency of coated sand and limestone as filtering media. Maximum removal of iron (99.8 %) was obtained with coated sand at a dose of 5 g/100 ml and by adding 0.2 g/100 ml of limestone at pH 7.3. Arsenic (III) removal efficiency increased with the increased dose of coated sand and was best removed at pH 7.12. The maximum adsorption capacity for arsenic (III) obtained from Langmuir model was found to be 0.075 mg/g and the kinetics data followed pseudo-first order better than pseudo-second order. Energy dispersive X-ray analysis and FT-IR study proved the removal of iron and arsenic. Column experiment showed removal of iron and arsenic (III) to <0.3 mg/l and 10 ?g/l, respectively, from an initial concentration of 20 mg/l (iron) and 200 ?g/l (arsenic).

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

2014-06-01

152

Adsorption-dissolution reactions affecting the distribution and stability of CoIIEDTA in ion oxide-coated sand  

International Nuclear Information System (INIS)

The time-variant chemical behavior of CoIIEDTA (and other metal-EDTA complexes) was investigated in suspensions of iron oxide-coated sand to identify equilibrium and kinetic reactions that control the mobility of MeII-EDTA complexes in subsurface environments. Batch experiments were conducted to evaluate the adsorption as a function of pH, concentration, and time and to quantify the rate-controlling step(s) of dissolution of the iron oxide by EDTA complexes. Ionic Co2+ exhibited typical cation-like adsorption, whereas MeIIEDTA adsorption was ligand-like, increasing with decreasing pH. Adsorption isotherms for all reactive species exhibited Langmuir behavior, with site saturation occurring at molar values of tot. The adsorption of MeIIEDTA enhanced the apparent solubility of the iron oxide phase, which destabilized the CoIIEDTA complex, liberating Co2+ and FeIIIEDTA. The dissolution rate was an order of magnitude slower at pH 6.5 than at pH 4.5 and was influenced by the re-adsorption of solubilized FeIIIEDTA. Two multireaction kinetic models were developed that each included Langmuir adsorption for Co2+ and metal-EDTA species but differed in their depiction of the dissolution mechanism (i.e., ligand-versus proton-promoted dissolution). 45 refs., 8 figs., 6 tabs

1994-09-01

153

Lead adsorption, chemically-enhanced desorption, and equilibrium modeling in an iron-oxide-coated sand, synthetic groundwater system  

Energy Technology Data Exchange (ETDEWEB)

Oxides of iron are ubiquitous subsurface mineral constituents and control the mobility of metal ions in soils and groundwater by adsorptive retardation. In this laboratory study, iron-oxide-coated sand (IOCS) is used to model lead chemical behavior in soil using batch and column reactor experiments. Several parameters are varied in order to ascertain their effects: pH, ionic strength, complexation by organic ligands, competing cations, and reaction time. In equilibrium experiments, pH was the major factor that controlled the adsorption process, and increasing ionic strength somewhat decreased Pb adsorption below pH = 5 but had no influence at higher pH values. Using a surface complexation, triple-layer model (TLM), an inner-sphere surface reaction was successful in describing the effect of pH on Pb adsorption on IOCS over a range of Pb concentrations at constant ionic strength. EDTA greatly decreased Pb adsorption at equimolar and greater concentrations, with its effect increasing with pH above 6.0, but with a enhanced adsorption at acidic pHs below about 4.5. Soil column studies of Pb adsorption on IOCS are consistent with expectations from batch studies. Results of this study provide guidance in determining conditions that chemically enhance mobilization or immobilization of Pb in soil and groundwater.

Nelson, P.O.; Azizian, M.F. [Oregon State Univ., Corvallis, OR (United States)

1996-10-01

154

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

Energy Technology Data Exchange (ETDEWEB)

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 {approx} 1% tensile strain can reduce the total time to failure by as much as a third.

Sierros, Konstantinos A. [West Virginia University, Department of Mechanical and Aerospace Engineering, Morgantown, WV, 26506 (United States)], E-mail: kostas.sierros@mail.wvu.edu; Morris, Nicholas J.; Ramji, Karpagavalli; Cairns, Darran R. [West Virginia University, Department of Mechanical and Aerospace Engineering, Morgantown, WV, 26506 (United States)

2009-02-27

155

Formation of microarc oxidation coatings on magnesium alloy with photocatalytic performance  

Science.gov (United States)

Microarc oxidation (MAO) coatings were prepared on AZ91D magnesium alloy in a phosphate electrolyte with and without TiO2 nanoparticles. The effect of TiO2 nanoparticles in the electrolyte on the thickness, surface morphology, composition, structure, corrosion resistance and photocatalytic performance of the coatings were investigated. The appearance and structure of the coatings changed significantly after the TiO2 nanoparticles were added into the electrolyte. The coatings produced in the phosphate electrolyte displayed a grayish white appearance and were mainly composed of MgO and Mg3(PO4)2. However, the coatings formed in the electrolyte with various TiO2 nanoparticles had a blueish color and, additionally, contained the rutile TiO2 and Mg2TiO4. The results of corrosion and photocatalytic measurements show that the coatings formed in the electrolyte with TiO2 nanoparticles not only provided better corrosion protection for magnesium alloy but also exhibited photocatalytic properties.

Li, Weiping; Tang, Mingqi; Zhu, Liqun; Liu, Huicong

2012-10-01

156

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

157

Enhanced capacitive performance of TiO2 nanotubes with molybdenum oxide coating  

Science.gov (United States)

Alpha-phase MoO3 is electrochemically deposited on well-aligned TiO2 nanotubes which are synthesized by anodic oxidation. The morphology, composition and electrochemical behaviors of MoO3-coated and bare TiO2 nanotubes are studied. The former deliver greatly higher capacitance than the latter and their performance can be readily optimized by varying MoO3 deposition cycles. The large areal capacitance of 209.6 mF cm-2 at a scan rate of 5 mV s-1 is firstly achieved for TiO2 nanotube array electrode. In addition, the coated TiO2 nanotubes show significantly more capacitance than a dense MoO3 film. For example, they exhibit a capacitance up to 74.9 F g-1 at 5 mV s-1 in 1 M KCl solution, while the dense film only shows a capacitance of 32.3 F g-1 under same conditions. Such improvement is found ascribed to MoO3 with high pseudocapacity and TiO2 nanotubes with large surface area allowing efficient MoO3 nanoparticle loading and rapid charge transfer. This nanostructured electrode with features of facile synthesis and excellent performance is believed as a potential candidate for supercapacitor applications.

Guan, Dongsheng; Gao, Xianfeng; Li, Jianyang; Yuan, Chris

2014-05-01

158

The phase and microstructural analysis of protective oxide coatings on molybdenum  

International Nuclear Information System (INIS)

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

2011-01-01

159

Osteoblast responses to different oxide coatings produced by the sol-gel process on titanium substrates.  

Science.gov (United States)

In order to improve the osseointegration of endosseous implants made from titanium, the structure and composition of the surface were modified. Mirror-polished commercially pure (cp) titanium substrates were coated by the sol-gel process with different oxides: TiO(2), SiO(2), Nb(2)O(5) and SiO(2)-TiO(2). The coatings were physically and biologically characterized. Infrared spectroscopy confirmed the absence of organic residues. Ellipsometry determined the thickness of layers to be approximately 100nm. High resolution scanning electron microscopy (SEM) and atomice force microscopy revealed a nanoporous structure in the TiO(2) and Nb(2)O(5) layers, whereas the SiO(2) and SiO(2)-TiO(2) layers appeared almost smooth. The R(a) values, as determined by white-light interferometry, ranged from 20 to 50nm. The surface energy determined by the sessile-drop contact angle method revealed the highest polar component for SiO(2) (30.7mJm(-2)) and the lowest for cp-Ti and 316L stainless steel (6.7mJm(-2)). Cytocompatibility of the oxide layers was investigated with MC3T3-E1 osteoblasts in vitro (proliferation, vitality, morphology and cytochemical/immunolabelling of actin and vinculin). Higher cell proliferation rates were found in SiO(2)-TiO(2) and TiO(2), and lower in Nb(2)O(5) and SiO(2); whereas the vitality rates increased for cp-Ti and Nb(2)O(5). Cytochemical assays showed that all substrates induced a normal cytoskeleton and well-developed focal adhesion contacts. SEM revealed good cell attachment for all coating layers. In conclusion, the sol-gel-derived oxide layers were thin, pure and nanostructured; consequent different osteoblast responses to those coatings are explained by the mutual action and coadjustment of different interrelated surface parameters. PMID:18440883

Ochsenbein, Anne; Chai, Feng; Winter, Stefan; Traisnel, Michel; Breme, Jürgen; Hildebrand, Hartmut F

2008-09-01

160

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

Science.gov (United States)

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

Sliney, Harold E.

1960-01-01

 
 
 
 
161

Krypton retention on solid adsorbents  

International Nuclear Information System (INIS)

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

1980-10-23

162

The influence of substrate chemistry on the adhesion of electrolessly deposited Ni(P) on metal oxide coated ceramics  

Energy Technology Data Exchange (ETDEWEB)

The adhesion of electrolessly deposited Ni(P) on alumina ceramic substrates which were coated with thin SiO[sub 2], SnO[sub 2], TiO[sub 2], Al[sub 2]O[sub 3], Y[sub 2]O[sub 3], ZrO[sub 2] and (In,Sn)O[sub x] (ITO) films was studied. The adhesion was measured with the aid of the 90 peel test. Strong adhesion of Ni(P) was found for the substrates with ZrO[sub 2] and Al[sub 2]O[sub 3] coatings and weak adhesion for the substrates with SiO[sub 2], TiO[sub 2], SnO[sub 2], Y[sub 2]O[sub 3] and ITO coatings. The fracture path and the type of interfacial bonding were analysed using scanning electron microscopy, energy-dispersive analysis of X-rays and X-ray photoelectron spectroscopy. In the case of the strongly adhering samples, fracture took place through the metal layer and along the interface. In the case of the weakly adhering samples only interfacial failure was observed between the Ni(P) layer and the metal oxide coating. Cross-section transmission electron microscopy studies of the interfaces suggested that the differences in peel energy values are caused by differences in micromechanical interlocking at the metal oxide-Ni(P) interface. In addition, a weak boundary layer which was found to be present at the Ni(P)-alumina interface was absent in the case of the strongly adhering samples with the ZrO[sub 2] substrate coating. ((orig.))

Severin, J.W. (Philips Research Laboratories, Prof. Holstlaan 4, 5656 AA Eindhoven (Netherlands)); Weert, A.A.M. van (Philips Research Laboratories, Prof. Holstlaan 4, 5656 AA Eindhoven (Netherlands)); With, G. de (Philips Research Laboratories, Prof. Holstlaan 4, 5656 AA Eindhoven (Netherlands))

1994-10-01

163

Combined removal of SO2 and NO using sol-gel-derived copper oxide coated alumina sorbents/catalysts.  

Science.gov (United States)

The present paper reports experimental results on the removal of sulfur dioxide and nitrogen oxide from simulated flue gas using a copper oxide coated on alumina sorbent/catalyst prepared by the sol-gel method. Selective catalytic reduction of nitric oxide by ammonia over sol-gel derived CuO/gamma-Al2O3 sorbents/catalysts with different degrees of sulfation was studied in a fixed-bed packed reactor. The optimum temperature for NO reduction was found at 350 degrees C for both fresh and sulfated catalysts. The properties for simultaneous removal of SO2 and NO by the sol-gel-derived CuO/gamma-Al2O3 sorbents were studied using simulated dry flue gas. The optimum operating temperature for the combined deSO2/deNO operations was identified at 350 degrees C. At the space velocity of 5200 h(-1) and 350 degrees C, a fixed-bed reactor packed with the 7.9 wt% CuO/gamma-Al2O3 sorbent prepared by the sol-gel method offers SO2 sorption capacity of 2.3 mmol g(-1) and NO conversion of 92% with a dry simulated flue gas as the feed. Under these experimental conditions, the sol-gel derived sorbents/catalysts have comparable efficiency for removal of SO2 and NOx as their commercial counterparts. The significantly higher crush strength of the sol-gel derived sorbents/catalysts make them very promising for their use in the copper oxide process for combined removal of SO2 and NOx from flue gas in a single unit operation. PMID:14599142

Buelna, G; Lin, Y S

2003-09-01

164

Carbon nanotubes - the promising adsorbent in wastewater treatment  

International Nuclear Information System (INIS)

Carbon materials are a class of significant and widely used engineering adsorbent. As a new member of the carbon family, carbon nanotubes have exhibited great potentials in applications as composite reinforcements, field emitters for flat panel display, sensors, energy storage and energy conversion devices, and catalysts support phases, because of their extraordinary mechanical, electrical, thermal and structural properties. In particular, the large specific surface areas, as well as the high chemical and thermal stabilities, make carbon nanotubes an attractive adsorbent in wastewater treatment. The adsorption properties of the carbon nanotubes to a series of toxic agents, such as lead, cadmium and 1, 2-dichlorobenzene have been studied and the results show that carbon nanotubes are excellent and effective adsorbent for eliminating these harmful media in water. The effects of the morphologies and the surface status on the carbon nanotube adsorption capacities are also discussed

2007-03-01

165

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

166

Water vapor adsorption characteristics of honeycomb adsorbents  

International Nuclear Information System (INIS)

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

2010-12-01

167

Dispersed-phase adsorbents for biotechnology applications.  

Science.gov (United States)

A new type of adsorbent material has been developed in which very small adsorbent particles are entrapped in a hydrocolloidal gel matrix that is formed into small, monodisperse spherical beads. Examples of applications of this type of material include dis...

C. D. Scott

1987-01-01

168

Effects of adsorbates on submonolayer growth  

CERN Document Server

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

169

Intrinsic friction of adsorbed monolayers  

CERN Document Server

In the present paper we overview our recent results on intrinsic frictional properties of adsorbed monolayers, composed of mobile hard-core particles undergoing continuous exchanges with a vapor phase. Within the framework of a dynamical master equation approach, describing the time evolution of the system, we determine in the most general form the terminal velocity of some biased impure molecule - the tracer particle (TP), constrained to move inside the adsorbed monolayer probing its frictional properties, define the frictional forces as well as the particles density distribution in the monolayer. Results for one-dimensional solid substrates, appropriate to adsorbtion on polymer chains, are compared against the Monte Carlo simulation data, which confirms our analytical predictions.

Bénichou, O; Coninck, J D; Moreau, M; Oshanin, G

2001-01-01

170

Synthesis of Polypropylene Fiber/Hydrated Iron Oxide Nanocomposite Adsorbent  

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Composite adsorbent based on the polypropylene fibers with chemically bound nanoparticles of hydrated iron (III) oxide were synthesized by two-stage experiment: radiation-induced graft polymerization of acrylic acid onto the surface of polypropylene fibers followed by the in-situ formation of hydrated iron oxide nanoparticles and their stabilization on the fibers’ surface within the grafted layer. SEM and XRD investigations revealed a compact homogeneous layer of amorphous nanoaggregates (7...

2013-01-01

171

Preparations of PAN-based adsorbers for separation of cesium and cobalt from radioactive wastes  

International Nuclear Information System (INIS)

Ion-exchange adsorbers are widely used for radioisotope separation, as well as for the removal of hazardous fission products from aqueous waste prior to discharge to the environment. Inorganic exchangers are of particular interest because of their resistance to radiolytic damage and selectivity for specific fission products. Composite inorganic-organic adsorbers represent a group of inorganic ion exchangers modified by using binding organic material, polyacrylonitrile, for preparation of larger size particles with higher granular strength. At the same time, kinetics of ion exchange and sorption capacity of such composite adsorbers are not influenced by the binding polymer. The contents of active component in composite adsorber were varied over a very broad range of 5-95% of the dry weight of the composite adsorber, and tested for separation and concentration of various stimulated wastes. Three different inorganic sorbents, granular hexacyanoferrate-based ion exchanger, were developed for the removal of Cs and Co ions from waste solutions containing different complexing agents as detergents. Radiation and thermal stability studies show that these adsorbents can be used for medium-active waste treatment

2007-05-01

172

Preparations of PAN-based adsorbers for separation of cesium and cobalt from radioactive wastes  

Energy Technology Data Exchange (ETDEWEB)

Ion-exchange adsorbers are widely used for radioisotope separation, as well as for the removal of hazardous fission products from aqueous waste prior to discharge to the environment. Inorganic exchangers are of particular interest because of their resistance to radiolytic damage and selectivity for specific fission products. Composite inorganic-organic adsorbers represent a group of inorganic ion exchangers modified by using binding organic material, polyacrylonitrile, for preparation of larger size particles with higher granular strength. At the same time, kinetics of ion exchange and sorption capacity of such composite adsorbers are not influenced by the binding polymer. The contents of active component in composite adsorber were varied over a very broad range of 5-95% of the dry weight of the composite adsorber, and tested for separation and concentration of various stimulated wastes. Three different inorganic sorbents, granular hexacyanoferrate-based ion exchanger, were developed for the removal of Cs and Co ions from waste solutions containing different complexing agents as detergents. Radiation and thermal stability studies show that these adsorbents can be used for medium-active waste treatment.

Nilchi, A. [Jaber Ibn Hayan Research Laboratories, Atomic Energy Organization of Iran, P.O. Box 11365/8486, Tehran (Iran, Islamic Republic of)]. E-mail: anilchi@aeoi.org.ir; Atashi, H. [Sistan and Baluchestan University, Zahedan (Iran, Islamic Republic of); Javid, A.H. [Azad University, Tehran (Iran, Islamic Republic of); Saberi, R. [Jaber Ibn Hayan Research Laboratories, Atomic Energy Organization of Iran, P.O. Box 11365/8486, Tehran (Iran, Islamic Republic of)

2007-05-15

173

Preparations of PAN-based adsorbers for separation of cesium and cobalt from radioactive wastes.  

Science.gov (United States)

Ion-exchange adsorbers are widely used for radioisotope separation, as well as for the removal of hazardous fission products from aqueous waste prior to discharge to the environment. Inorganic exchangers are of particular interest because of their resistance to radiolytic damage and selectivity for specific fission products. Composite inorganic-organic adsorbers represent a group of inorganic ion exchangers modified by using binding organic material, polyacrylonitrile, for preparation of larger size particles with higher granular strength. At the same time, kinetics of ion exchange and sorption capacity of such composite adsorbers are not influenced by the binding polymer. The contents of active component in composite adsorber were varied over a very broad range of 5-95% of the dry weight of the composite adsorber, and tested for separation and concentration of various stimulated wastes. Three different inorganic sorbents, granular hexacyanoferrate-based ion exchanger, were developed for the removal of Cs and Co ions from waste solutions containing different complexing agents as detergents. Radiation and thermal stability studies show that these adsorbents can be used for medium-active waste treatment. PMID:17270450

Nilchi, A; Atashi, H; Javid, A H; Saberi, R

2007-05-01

174

Enhanced encapsulation of metoprolol tartrate with carbon nanotubes as adsorbent  

Science.gov (United States)

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

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

2011-12-01

175

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

International Nuclear Information System (INIS)

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

2013-02-15

176

Comparison of Lead Removal by Various Types of Swine Bone Adsorbents  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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 ads...

2010-01-01

177

Molecular filtration : the study of adsorbents  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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

Twumasi, Ebenezer

2011-01-01

178

Mean chain length of adsorbed supramolecular polymers  

Digital Repository Infrastructure Vision for European Research (DRIVER)

We present a theoretical study of reversible supramolecular polymers near an adsorbing surface. Mean chain lengths for free and adsorbed supramolecular polymers were calculated for a broad range of concentrations. As far as we know, this is the first report that describes a regime where the mean chain length decreases with increasing monomer concentration. It is shown that this anomalous behavior is caused by a change of the structure of the adsorbed layer

Zweistra, H. J. A.; Besseling, N. A. M.

2006-01-01

179

Oxygen evolution on Ir-Ru-Sn ternary oxide-coated electrodes in H[sub 2]SO[sub 4] solution: An approach employing statistical experimental strategy  

Energy Technology Data Exchange (ETDEWEB)

A systematic modeling analysis of Ir-Ru-Sn ternary oxide-coated electrodes fabricated by thermal decomposition is performed. Using mixture experimental design, empirical models are fitted and plotted as contour diagrams which facilitate comparisons with experimental trends noted by other investigators and reveal the synergistic/antagonistic effects between the mixed oxides. The results indicate that each component demonstrates different performances in either binary (Ir-Ru, Ir-Sn, and Ru-Sn) or ternary (Ir-Ru-Sn) systems, with the Ir 75% binary electrode being by far the most valuable anodic candidate for oxygen evolution in acidic media. X-ray photoelectron spectroscopy analysis shows that the Ir 75%-Ru 25% binary electrode surface is enriched with Ir, while Auger electron spectroscopy depth profile results demonstrate inhomogeneous bulk.

Shihmin Lin; Tenchen Wen (National Cheng Kung Univ., Tainan (Taiwan, Province of China). Dept. of Chemical Engineering)

1993-08-01

180

Application of vapor phase decomposition techniques (VPD/AAS and ICP-MS) for trace element analysis in oxide coatings on silicon  

International Nuclear Information System (INIS)

The use of VPD/AAS and ICP-MS techniques to measure metallic contamination in a silicon oxide film is described. Metallic contamination such as Na, Al, Ca, Cr, Fe, Cu and Zn which may be introduced during cleaning, etching oxide growth and ion implantation processes is demonstrated to be reliably and accurately monitored by this technique. In VPD techniques, an oxide film is decomposed by hydrofluoric acid vapor and all the metals on the silicon wafer surface are dissolved into a small volume of liquid. The liquid is then transferred to an AAS equipped with a graphite furnace or an ICP-MS for metal analysis. Since the entire oxide film is dissolved for analysis, VPD technique measures the average concentration of a metal in an oxide coating. Surface metal concentration as low as 109-1010 atoms/cm2 may be detected by these techniques. (orig.)

1995-05-01

 
 
 
 
181

Modification of optical and electrical properties of zinc oxide-coated porous silicon nanostructures induced by swift heavy ion  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Morphological and optical characteristics of radio frequency-sputtered zinc aluminum oxide over porous silicon (PS) substrates were studied before and after irradiating composite films with 130?MeV of nickel ions at different fluences varying from 1?×?1012 to 3?×?1013 ions/cm2. The effect of irradiation on the composite structure was investigated by scanning electron microscopy, X-ray diffraction (XRD), photoluminescence (PL), and cathodoluminescence spectroscopy. Current–voltag...

Kumar, Yogesh; Herrera-zaldivar, Manuel; Olive-me?ndez, Sion Federico; Singh, Fouran; Mathew, Xavier; Agarwal, Vivechana

2012-01-01

182

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

Digital Repository Infrastructure Vision for European Research (DRIVER)

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

Du Yu-cheng, Yan Jing

2011-01-01

183

Ecological applications of the irradiated adsorbents  

International Nuclear Information System (INIS)

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

2004-10-01

184

Mesoporous carbon nanomaterials as environmental adsorbents.  

Science.gov (United States)

The transportation and diffusion of the guest objects or molecules in the porous carbon nanomaterials can be facilitated by reducing the pathway and resistance. The reduced pathway depends on the porous nature of carbon nanomaterials. Classification of porous carbon materials by the International Union of Pure and Applied Chemistry (IUPAC) has given a new opportunity to design the pores as per their applicability and to understand the mobility of ions, atoms, and molecules in the porous network of carbon materials and also advanced their countless applicability. However, synthesis of carbon nanomaterials with a desired porous network is still a great challenge. Although, remarkable developments have taken place in the recent years, control over the pores size and/or hierarchical porous architectures, especially in the synthesis of carbon nanospheres (CNSs) and ordered mesoporous carbon (OMCs) is still intriguing. The micro and mesoporous CNSs and OMCs have been prepared by a variety of procedures and over a wide range of compositions using various different surfactant templates and carbon precursors etc. The mechanisms of formation of micromesopore in the CNSs and OMCs are still evolving. On the other hand, the urge for adsorbents with very high adsorption capacities for removing contaminants from water is growing steadily. In this review, we address the state-of-the-art synthesis of micro and mesoporous CNSs and OMCs, giving examples of their applications for adsorptive removals of contaminants including our own research studies. PMID:24749459

Tripathi, Pranav K; Gan, Lihua; Liu, Mingxian; Rao, Nageswara N

2014-02-01

185

Electrochemical corrosion behaviour of plasma electrolytic oxidation coatings on AM50 magnesium alloy formed in silicate and phosphate based electrolytes  

International Nuclear Information System (INIS)

PEO coatings were produced on AM50 magnesium alloy by plasma electrolytic oxidation process in silicate and phosphate based electrolytes using a pulsed DC power source. The microstructure and composition of the PEO coatings were analyzed by scanning electron microscopy (SEM) and X-ray Diffraction (XRD). The corrosion resistance of the PEO coatings was evaluated using open circuit potential (OCP) measurements, potentiodynamic polarisation tests and electrochemical impedance spectroscopy (EIS) in 0.1 M NaCl solution. It was found that the electrolyte composition has a significant effect on the coating evolution and on the resulting coating characteristics, such as microstructure, composition, coating thickness, roughness and thus on the corrosion behaviour. The corrosion resistance of the PEO coating formed in silicate electrolyte was found to be superior to that formed in phosphate electrolyte in both the short-term and long-term electrochemical corrosion tests.

2009-05-30

186

Fluorescence dynamics of microsphere-adsorbed sunscreens  

Science.gov (United States)

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

Krishnan, R.

2005-03-01

187

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

International Nuclear Information System (INIS)

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

1993-06-07

188

On-line monitoring methodology for determining E/sub r/ in carbon adsorber exhaust air  

Energy Technology Data Exchange (ETDEWEB)

Methodology was developed to determine the concentrations of US OSHA-regulated and odorous gaseous species in the adsorber exhaust air from a vehicle coating operation at an automotive assembly plant and to define appropriate instrumentation for the continuous monitoring of these species. On-line gas chromatography (GC) and total hydrocarbon (THC) instruments were employed. The main species identified in the adsorber effluent were n-butanol, methyl ethyl ketone, ethanol and ethyl acetate. The time for the adsorber effluent concentration to reach a fraction (E/sub r/) equal to 10% of the US OSHA value for the combined solvent mixture depended on the adsorber influent concentration. The correlation between the GC and the THC varied between 2 and 17%. The E/sub r/ value can be predicted by THC monitoring as long as the qualitative composition of the exhaust air does not change significantly. 13 references, 3 figures, 4 tables.

1984-07-01

189

Modification of optical and electrical properties of zinc oxide-coated porous silicon nanostructures induced by swift heavy ion  

Science.gov (United States)

Morphological and optical characteristics of radio frequency-sputtered zinc aluminum oxide over porous silicon (PS) substrates were studied before and after irradiating composite films with 130?MeV of nickel ions at different fluences varying from 1?×?1012 to 3?×?1013 ions/cm2. The effect of irradiation on the composite structure was investigated by scanning electron microscopy, X-ray diffraction (XRD), photoluminescence (PL), and cathodoluminescence spectroscopy. Current–voltage characteristics of ZnO-PS heterojunctions were also measured. As compared to the granular crystallites of zinc oxide layer, Al-doped zinc oxide (ZnO) layer showed a flaky structure. The PL spectrum of the pristine composite structure consists of the emission from the ZnO layer as well as the near-infrared emission from the PS substrate. Due to an increase in the number of deep-level defects, possibly oxygen vacancies after swift ion irradiation, PS-Al-doped ZnO nanocomposites formed with high-porosity PS are shown to demonstrate a broadening in the PL emission band, leading to the white light emission. The broadening effect is found to increase with an increase in the ion fluence and porosity. XRD study revealed the relative resistance of the film against the irradiation, i.e., the irradiation of the structure failed to completely amorphize the structure, suggesting its possible application in optoelectronics and sensing applications under harsh radiation conditions.

2012-01-01

190

Composite  

Science.gov (United States)

Particle distribution and hot workability of an in situ Al-TiCp composite were investigated. The composite was fabricated by an in situ casting method using the self-propagating high-temperature synthesis of an Al-Ti-C system. Hot-compression tests were carried out, and power dissipation maps were constructed using a dynamic material model. Small globular TiC particles were not themselves fractured, but the clustering and grain boundary segregation of the particles contributed to the cracking of the matrix by causing the debonding of matrix/particle interfaces and providing a crack propagation path. The efficiency of power dissipation increased with increasing temperature and strain rate, and the maximum efficiency was obtained at a temperature of 723 K (450 °C) and a strain rate of 1/s. The microstructural mechanism occurring in the maximum efficiency domain was dynamic recrystallization. The role of particles in the plastic flow and the microstructure evolution were discussed.

Kim, Su-Hyeon; Cho, Young-Hee; Lee, Jung-Moo

2014-06-01

191

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

192

Electric Properties of Adsorbed Polystyrenesulfonate.  

Science.gov (United States)

Counterion polarization of sodium and magnesium polystyrenesulfonate (NaPSS and MgPSS), adsorbed in an excess onto ellipsoidal beta-ferric hydrous oxide particles (beta-FeOOH), is studied in both the absence and the presence of added simple electrolytes, NaCl and MgCl(2). The amplitude of the low-frequency (10(2)-10(4) Hz) and the high-frequency (10(4)-10(6) Hz) electro-optical effects of NaPSS is found to decrease with increasing NaCl concentration, while the critical frequency of relaxation of both effects remains unchanged. Addition of MgCl(2) to the suspension containing MgPSS also reduces the amplitude of the low-frequency electro-optical effect, but the amplitude of the high-frequency effect increases. The increased number of mobile (not bound) divalent ions, which produce larger charge fluctuation, could explain the high-frequency effect increase in the presence of a small excess of MgCl(2). Substitution of Na(+) counterions of PSS by Mg(2+) is found to increase the critical frequency of relaxation and to reduce the amplitude of the low-frequency effect, probably due to the strong repulsion between bound divalent counterions. The polyion length remains nearly unchanged during this substitution, as evidenced by the constant relaxation time of the polyelectrolyte-coated particles. The increase of counterion valence is not found to affect the amplitude of the high-frequency electro-optical effect in the absence of added salt. Copyright 1999 Academic Press. PMID:10550248

Radeva

1999-12-01

193

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)

1998-05-03

194

Inner structure of adsorbed ionic microgel particles.  

Science.gov (United States)

Microgel particles of cross-linked poly(NIPAM-co-acrylic acid) with different acrylic acid contents are investigated in solution and in the adsorbed state. As a substrate, silicon with a poly(allylamine hydrochloride) (PAH) coating is used. The temperature dependence of the deswelling of the microgel particles was probed with atomic force microscopy (AFM). The inner structure of the adsorbed microgel particles was detected with grazing incidence small angle neutron scattering (GISANS). Small angle neutron scattering (SANS) on corresponding microgel suspensions was performed for comparison. Whereas the correlation length of the polymer network shows a divergence in the bulk samples, in the adsorbed microgel particles it remains unchanged over the entire temperature range. In addition, GISANS indicates changes in the particles along the surface normal. This suggests that the presence of a solid surface suppresses the divergence of internal fluctuations in the adsorbed microgels close to the volume phase transition. PMID:24920223

Wellert, Stefan; Hertle, Yvonne; Richter, Marcel; Medebach, Martin; Magerl, David; Wang, Weinan; Demé, Bruno; Radulescu, Aurel; Müller-Buschbaum, Peter; Hellweg, Thomas; von Klitzing, Regine

2014-06-24

195

Development of adsorbent for radioactive carbon dioxide  

International Nuclear Information System (INIS)

To develop an effective adsorbent for radioactive Carbon Dioxide, 14CO2, which is discharged to nearby atmosphere from nuclear power plants of CANDU type, we made some preliminary adsorbents and tested their abilities of CO2 removal. The chemical agents used was LiOH and we supported or impregnated it on the surface or the internal volume of activated Carbon(GW-H). The physical and chemical properties of various adsorbents were measured using methods such as XRD, BET. SEM images were taken to investigate the change of surface morphology of the adsorbents. Finally, amount of CO2 adsorption of them were verified under specific conditions. We found that mechanical mixing of LiOH and activated Carbon by Nitric Acid-treatment enhanced its CO2 removal efficiency to some degree

2003-11-27

196

Scattering studies of pluronics adsorbed on laponite  

International Nuclear Information System (INIS)

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

2003-06-25

197

IR investigations of surfaces and adsorbates  

CERN Document Server

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

Gwyn, W

2001-01-01

198

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

Directory of Open Access Journals (Sweden)

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

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

2011-10-01

199

Mesoporous Silica: A Suitable Adsorbent for Amines  

Directory of Open Access Journals (Sweden)

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

Abdollahzadeh-Ghom Sara

2009-01-01

200

Zeolites as alcohol adsorbents from aqueous solutions  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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...

Cekova Blagica; Kocev Dragi; Kolcakovska Elena; Stojanova Daniela

2006-01-01

 
 
 
 
201

Adsorption cooling using adsorbent-coated surfaces  

Energy Technology Data Exchange (ETDEWEB)

UOP has developed a technology for applying zeolite adsorbents directly to heat exchange surfaces. This paper demonstrates the effectiveness of using adsorbent-coated surfaces for adsorption cooling. Experimental results are presented for a two-bed system in which a UOP proprietary adsorbent is applied to heat exchange surfaces and water is used as the refrigerant. Because of small heat-transfer and mass-transfer resistance in the adsorbent coating, we can run the process at extremely short cycle times, resulting in a large specific cooling power (Watts per kilogram of adsorbent). The adsorbent developed for this application can be regenerated at low temperatures (95 to 110 C), which makes the UOP process ideal for industrial cooling applications when low-grade waste heat is available. (orig.) [German] Die Firma UOP GmbH hat neue Adsorbenzien entwickelt, die fuer solare Adsorptions-Waermepumpen besonders geeignet sind. DZZ-70 (bisheriger experimenteller Name: SC-9) ist ein Zeolith, der sich bereits bei niedrigen Temperaturen (95-110 C) regenerieren laesst. Neu ist auch die direkte Beschichtung von Waermetauscherblechen mit DZZ-70. Der wesentlich verbesserte Waermeuebergang fuehrt zu kuerzeren Zykluszeiten und damit zu hoeheren Kuehlleistungen. Es wird eine experimentelle Anlage vorgestellt, die mit einer DZZ-70 Beschichtung eine 6-fach groessere Kuehlleistung als mit herkoemmlichen 13X Zeolith in Kugelform erreicht. (orig.)

Dunne, S.R.; Taqvi, S.M. [UOP, Des Plaines, IL (United States)

2001-07-01

202

Reconformation of polyvinylamine adsorbed on glass fibers.  

Science.gov (United States)

Surface area exclusion chromatography was used to investigate the reconformation of fully hydrolyzed polyvinylamine. The polymer is adsorbed on stacked glass fiber filters constituting the stationary phase while the polymer solution is injected at the inlet of the chromatography column. From numerical simulation and experimental chromatograms of nonreconforming polyelectrolytes, the amount of polymer adsorbed per filter represented as a function of the filter position along the column (the histogram) was determined to be continuously decreasing and not to depend on the rate of elution. For polyvinylamine, the histograms are peaked and the height of the peak was determined to depend greatly on the rate of polymer supply to the column that was controlled by monitoring the polymer concentration and/or the rate of elution (mass-transfer-controlled adsorption). Modifications in the adsorption on the successive filters were converted into changes in the interfacial area of adsorbed molecules taking into account model histograms as well as experimental adsorption histograms of non reconforming systems. Macromolecule concentration in the mobile phase and contact time between solute and adsorbed molecules were determined to be the two parameters controlling the extent of polymer desorption. The unusual shape of the histogram thus was attributed to reconformation of the adsorbed polymer, which was stimulated by interfacial exchange between segments belonging to trains of adsorbed macromolecules and chain segments of solute ones. PMID:12885546

Widmaier, Josiane; Shulga, Alexander; Pefferkorn, Emile; Champ, Simon; Auweter, Helmut

2003-08-01

203

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

Directory of Open Access Journals (Sweden)

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

A. Dudek

2008-09-01

204

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

Science.gov (United States)

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

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

2014-04-01

205

Protective coatings based on composite materials  

International Nuclear Information System (INIS)

A study of the compatibility in compositions based on tungsten and molybdenum fibers with aluminum-oxide coatings in Nichrome matrices showed that a protective layer 1-3 ?m thick ensures stability of the reinforcing-phase-matrix contact at temperatures of 1100-1200 degrees C for 80-100 h. Yttrium, thorium, hafnium, and other oxides can also be used as barrier coatings, but they are brittle and sensitive to thermal shocks, and there is no universal method for depositing the oxides on continuous fibers

1986-02-01

206

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

Digital Repository Infrastructure Vision for European Research (DRIVER)

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

Yi Liu; Ryuichi Sugimoto; Katsuhiro Sumi

2013-01-01

207

Miscibility and interaction between 1-alkanol and short-chain phosphocholine in the adsorbed film and micelles.  

Science.gov (United States)

The miscibility and interaction of 1-hexanol (C6OH) and 1-heptanol (C7OH) with 1,2-dihexanoyl-sn-glycero-3-phosphocholine (DHPC) in the adsorbed films and micelles were investigated by measuring the surface tension of aqueous C6OH-DHPC and aqueous C7OH-DHPC solutions. The surface density, the mean molecular area, the composition of the adsorbed film, and the excess Gibbs energy of adsorption g(H,E), were estimated. Further, the critical micelle concentration of the mixtures was determined from the surface tension versus molality curves; the micellar composition was calculated. The miscibility of the 1-alkanols and DHPC molecules in the adsorbed film and micelles was examined using the phase diagram of adsorption (PDA) and that of micellization (PDM). The PDA and the composition dependence of g(H,E) indicated the non-ideal mixing of the 1-alkanols and DHPC molecules due to the attractive interaction between the molecules in the adsorbed film, while the PDM indicated that the 1-alkanol molecules were not incorporated in the micelles within DHPC rich region. The dependence of the mean molecular area of the mixtures on the surface composition suggested that the packing property of the adsorbed film depends on the chain length of 1-alkanol: C6OH expands the DHPC adsorbed film more than C7OH. PMID:17560093

Takajo, Yuichi; Matsuki, Hitoshi; Kaneshina, Shoji; Aratono, Makoto; Yamanaka, Michio

2007-09-01

208

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

Directory of Open Access Journals (Sweden)

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

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

2013-08-01

209

Study of plutonium adsorption by fibrous adsorbent  

International Nuclear Information System (INIS)

Japan Atomic Energy Research Institute and Unitika Ltd. have been conducting, under a joint effort, development of an inorganic fibrous adsorbent (FAC), which is capable of adsorbing plutonium (Pu) contained in radioactive liquid waste and which is also able to contribute to reduction of the volume of ?-waste by incineration. The fibrous adsorbent constitutes fibrous activated carbon of coal tar pitch derivative and has the following characteristics: (1) It has a large surface area. (2) Carbon constitutes more than 90% in the adsorbent; it is physically and chemically stable as an inorganic adsorbent; it is easy to be incinerated. (3) It is easy to be formed or molded into different shapes such as cartridges, and handling of the material is extremely easy. By using various kinds of Pu solution, we carried out tests and evaluations on the equilibrium adsorption quantity of Pu by the fibrous adsorbent, the adsorption property of the material by flow-through column test and the incineration property of the material in the cold test. The tests show that: (1) adsorption of Pu is the best with 0.8?0.9 mg-Pu/g-FAC when the concentration of nitric acid is near 1 M; (2) as the concentration of nitric acid is increased, its adsorption capacity becomes poorer; (3) when Pu coexists with Uranium (U), the adsorption capacity becomes slightly inferior; (4) in the flow-through column test, no breakthrough of Pu was observed until the volume of Pu liquid becomes about 3 times larger than the column volume; (5) in the incineration tests in the cold test using a laboratory scale incinerator, no flying of particles or soot was observed; and (6) it is possible to get good incineration at 500 ? 600 degrees C. The above results show that, by using the fibrous adsorbent, it became possible to remove Pu from radioactive liquid waste by adsorption, to reduce the volume only to residual ash by incineration, and to reduce substantially the volume of ?-waste

1994-03-03

210

Novel Fiber-Based Adsorbent Technology; FINAL  

International Nuclear Information System (INIS)

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

2001-01-01

211

Interplay of polyelectrolytes with different adsorbing surfaces  

Science.gov (United States)

We study the adsorption of polyelectrolytes from solution onto different adsorbing surfaces, focusing on the electrostatic interactions. Measurements of the surface excess, fractional ionization of chargeable groups, segmental orientation, and adsorption kinetics were made using Fourier transform infrared spectroscopy in the mode of attenuated total reflection. Different adsorbing surfaces, from single solid surfaces, solid surfaces modified with adsorbed polymer layer, to fluid-like surfaces-biomembranes were adopted. Both atomic force microscopy (AFM) and fluorescent techniques were employed to investigate the fluid-like surfaces in the absence and in the presence of polyelectrolytes. The work focuses on three primary issues: (i) the charge regulation of weak polyelectrolytes on both homogeneous and heterogeneous surfaces, (ii) the dynamics of adsorption when the surface possesses reciprocal mobility, i.e., biomembrane surface, and (iii) the structural and dynamical properties of the fluid-like surfaces interacting with polyelectrolytes. We find that the ionization of chargeable groups in weak polyelectrolytes is controlled by the charge balance between the adsorbates and the surfaces. A new interpretation of ionization in the adsorbed layer provides a new insight into the fundamental problem of whether ions of opposite charge associate or remain separate. Bjerrum length is found to be a criterion for the onset of surface ionization suppression, which helps to predict and control the conformation transition of proteins. In addition to the effect of different surfaces on the adsorption behavior of polyelectrolytes, we also focused on the response of the surfaces to the adsorbates. Chains that encountered sparsely-covered surfaces spread to maximize the number of segment-surface contacts at rates independent of the molar mass. Surface reconstruction rather than molar mass of the adsorbing molecules appeared to determine the rate of spreading. This contrasts starkly with traditional polymer adsorption onto surfaces whose structure is "frozen" and unresponsive. Finally, preliminary studies on dynamical properties of biomembrane surfaces interacting with polyelectrolytes are presented, using fluorescence correlation spectroscopy (FCS). The significance is to characterize domains induced by polyelectrolyte binding.

Xie, Feng

212

Removal of cyanide by eggshell as low-cost adsorbent  

Directory of Open Access Journals (Sweden)

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

Ghorban Asgari

2013-05-01

213

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

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

Saleh, Mohamed A.

2013-05-15

214

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

Energy Technology Data Exchange (ETDEWEB)

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

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

2011-07-01

215

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

International Nuclear Information System (INIS)

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

1992-04-01

216

Preparation and Performance of Pre-coated Carbon Layer for Carbon/Carbon Composites  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Pre-coated carbon layers on the surface of carbon/carbon composites were prepared firstly by slurry and high-temperature treatment for preparing the anti-oxidation coating with SiC concentration gradient. The micrographs and microstructures of the pre-coated carbon layer were characterized by SEM, Raman and XRD. The effects of different graphite content and carbonization temperature on the microstructure of pre-coated carbon layer were investigated. The bonding strength between the carbon lay...

Zhang Yu-lei, Li He-jun

2009-01-01

217

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

Energy Technology Data Exchange (ETDEWEB)

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

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

2013-02-15

218

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

International Nuclear Information System (INIS)

Highlights: ? A TiO2/graphite composite coating is produced on Ti alloy by one-step PEO process. ? The TiO2/graphite composite coating exhibits excellent self-lubricating behavior. ? The self-lubricating composite coating improves the wear resistance by comparison to the conventional PEO coating. - Abstract: One-step plasma electrolytic oxidation (PEO) process in a graphite-dispersed phosphate electrolyte was used to prepare a graphite-containing oxide composite coating on Ti6Al4V alloy. The composition and microstructure of the oxide coatings produced in the phosphate electrolytes with and without addition of graphite were analyzed by X-ray diffractometer (XRD), Raman spectroscopy, X-ray photoelectron spectroscopy (XPS) and scanning electron microscopy (SEM). The tribological properties of the uncoated Ti6Al4V alloy and oxide coatings were evaluated using a reciprocating ball-on-disk tribometer. Results showed that the graphite-containing oxide composite coating can be successfully produced on Ti6Al4V alloy in the graphite-dispersed phosphate electrolyte using PEO process. The graphite-containing oxide composite coating registered much lower friction coefficient and wear rate than the uncoated Ti6Al4V alloy and the oxide coating without graphite under dry sliding condition, exhibiting excellent self-lubricating property.

2012-09-01

219

Preparation and tribological properties of self-lubricating TiO{sub 2}/graphite composite coating on Ti6Al4V alloy  

Energy Technology Data Exchange (ETDEWEB)

Highlights: Black-Right-Pointing-Pointer A TiO{sub 2}/graphite composite coating is produced on Ti alloy by one-step PEO process. Black-Right-Pointing-Pointer The TiO{sub 2}/graphite composite coating exhibits excellent self-lubricating behavior. Black-Right-Pointing-Pointer The self-lubricating composite coating improves the wear resistance by comparison to the conventional PEO coating. - Abstract: One-step plasma electrolytic oxidation (PEO) process in a graphite-dispersed phosphate electrolyte was used to prepare a graphite-containing oxide composite coating on Ti6Al4V alloy. The composition and microstructure of the oxide coatings produced in the phosphate electrolytes with and without addition of graphite were analyzed by X-ray diffractometer (XRD), Raman spectroscopy, X-ray photoelectron spectroscopy (XPS) and scanning electron microscopy (SEM). The tribological properties of the uncoated Ti6Al4V alloy and oxide coatings were evaluated using a reciprocating ball-on-disk tribometer. Results showed that the graphite-containing oxide composite coating can be successfully produced on Ti6Al4V alloy in the graphite-dispersed phosphate electrolyte using PEO process. The graphite-containing oxide composite coating registered much lower friction coefficient and wear rate than the uncoated Ti6Al4V alloy and the oxide coating without graphite under dry sliding condition, exhibiting excellent self-lubricating property.

Mu, Ming [The Ministry of Education Key Laboratory, Conveyance Tools and Equipment, East China Jiaotong University, Nanchang 330013 (China); State Key Laboratory of Solid Lubrication, Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences, Lanzhou 730000 (China); Zhou, Xinjian, E-mail: zhouxj63@126.com [The Ministry of Education Key Laboratory, Conveyance Tools and Equipment, East China Jiaotong University, Nanchang 330013 (China); Xiao, Qian [The Ministry of Education Key Laboratory, Conveyance Tools and Equipment, East China Jiaotong University, Nanchang 330013 (China); Liang, Jun, E-mail: jliang@licp.cas.cn [State Key Laboratory of Solid Lubrication, Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences, Lanzhou 730000 (China); Huo, Xiaodi [State Key Laboratory of Solid Lubrication, Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences, Lanzhou 730000 (China)

2012-09-01

220

Stent strut coverage of titanium-nitride-oxide coated stent compared to paclitaxel-eluting stent in acute myocardial infarction: TITAX-OCT study.  

Science.gov (United States)

Drug-eluting stents (DES) have reduced the rate of restenosis but recent studies have raised concern over the risk of late stent thrombosis (LST). Incomplete stent endothelialization and delayed vascular healing have been associated with LST. The titanium-nitride-oxide coated bio-active stent (BAS) has shown promising results in patients with acute coronary syndromes, but there is little long-term optical coherence tomography (OCT) data comparing BAS with DES. The TITAX-AMI trial is a prospective, randomized, multicenter trial comparing BAS to paclitaxel-eluting stent (PES) in 425 patients with acute myocardial infarction. A total of 18 patients (9 per group) with no major cardiac events during follow-up, were enrolled in this substudy >36 months (mean 47 months) after stent implantation. Quantitative coronary angiography was performed and stent strut endothelialization and vascular healing were assessed with OCT. The binary stent strut coverage was significantly higher in the BAS group compared with the PES group (99.6 vs. 89.2%, p < 0.001) and there were less malapposed struts in the BAS group (0.2 vs. 13.8%, respectively, p < 0.001). The neointimal hyperplasia (NIH) thickness (266 ± 166 vs. 126 ?m ± 126 ?m, p < 0.001) and percentage of NIH area (26.2 vs. 7.6%, p < 0.001) were greater in the BAS group than in the PES group. Late incomplete endothelialization was not uncommon after PES implantation. Stents in the BAS group were completely endothelialized. This difference may contribute to the more common LST after PES implantation in the TITAX-AMI trial. PMID:22362097

Lehtinen, Tuomas; Airaksinen, K E Juhani; Ylitalo, Antti; Karjalainen, Pasi P

2012-12-01

 
 
 
 
221

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

222

Thermal behaviour of bicomponent adsorbent of ZrO2-MnO2 system  

International Nuclear Information System (INIS)

A study was made on thermal behaviour of hydrated bicomponent adsorbent, containing 65 mol% zirconium dioxide and 35 mol% manganese dioxide. It is shown that highly dispersed solid phase of bicomponent adsorbent of mentioned composition is based on amorphous solid solution. Porous structure is presented by micro- and transition pores. Temperature growth in 100-740 deg C range results to dehydration, granule shrinkage and redistribution of microporous structure to transition-porous one. Crystallization of solid solution with formation of cubic lattice of fluorite type takes place at 600 deg C

1990-01-01

223

Organosilicon ion-exchange and complexing adsorbents  

International Nuclear Information System (INIS)

Data on the ion-exchange and complexing organosilicon adsorbents published during the last 10–12 years, including the results of systematic research of the authors, are summarized and analyzed. The following types of substances are considered: silicas with covalently grafted modifiers, silicas and aluminosilicates with non-covalently grafted modifiers and carbofunctional polyorganylsilsesquioxanes prepared by polycondensation of appropriate organosilicon monomers. Adsorbents of these types find extensive practical use, in particular, as analytical reagents for determination of metals in natural and artificial specimens, agents for isolation of valuable elements from industrial wastes and agents for removal of especially hazardous components from wastes and effluents. The bibliography includes 109 references.

2013-05-31

224

Indirect interactions of membrane-adsorbed cylinders  

CERN Document Server

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

225

Radon emanation from radium specific adsorbents.  

Science.gov (United States)

Pilot studies were undertaken to quantify the total activity of radon that is eluted following no-flow periods from several Ra-226 adsorbents loaded to near exhaustion. The adsorbents studied included two types of barium sulphate impregnated alumina (ABA-8000 and F-1) and Dowex MSC-1 resin treated by either barium hydroxide or barium chloride. In parallel, radium loaded plain activated aluminas and Dowex MSC-1 resin were similarly investigated. The results revealed that radon was quantitatively eluted during the first few bed volumes of column operation after no-flow periods. Although similar radon elution profiles were obtained, the position of the radon peak was found to vary and depended on the adsorbent type. Radon levels up to 24 and 14 kBq dm(-3) were measured after a rest period of 72h from radium exhausted Dowex MSC-1 treated with barium chloride and F-1 impregnated alumina with barium sulphate, respectively. The eluted radon values measured experimentally were compared to those calculated theoretically from accumulated radium quantities for the different media. For plain adsorbents, an agreement better than 10% was obtained. For treated resin-types a consistency within 30% but for impregnated alumina-types high discrepancy between respective values were obtained. PMID:19879620

Alabdula'aly, Abdulrahman I; Maghrawy, Hamed B

2010-01-01

226

Photoemission spectroscopy of surfaces and adsorbates  

Energy Technology Data Exchange (ETDEWEB)

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

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

1982-01-01

227

Photoemission spectroscopy of surfaces and adsorbates  

Energy Technology Data Exchange (ETDEWEB)

Core level photoelectron spectroscopy is providing new information concerning the electronic properties of adsorbates and surfaces. Several examples will be discussed, including studies of adsorbed rare gas submonolayers and multilayers as well as clean metal surfaces. For rare gas multilayers adsorbed on metal surfaces, the photoelectrons and Auger electrons exhibit well-resolved increases in kinetic energy with decreasing distance between the excited atom and the substrate, allowing a direct labeling of the layers. These energy shifts are mainly due to the substrate screening effects, and can be described well by an image-charge model. For a Kr/Xe bilayer system prepared by first coating a Pd substrate with a monolayer of Kr and then overcoating with a layer of Xe, a thermally activated layer inversion process is observed when the temperature is raised, with Xe coming in direct contact with the substrate. For rare gas submonolayers adsorbed on the Al(111) surface, coverage-dependent core level shift and work function measurements provide information about the adatom spatial distributions, polarizabilities, and dipole moments for the ground and excited states. The 2p core level shifts for a clean Al(001) surface relative to the bulk have also been studied. The shifts have a large contribution from the initial-state effects. 20 references, 7 figures, 2 tables.

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

1982-01-01

228

Factors influencing antibiotics adsorption onto engineered adsorbents.  

Science.gov (United States)

The study evaluated the adsorption of two antibiotics by four engineered adsorbents (hypercrosslinked resin MN-202, macroporous resin XAD-4, activated carbon F-400, and multi-walled carbon nanotubes (MWCNT)) from aqueous solutions. The dynamic results demonstrated the dominant influence of pore size in adsorption. The adsorption amounts of antibiotics on XAD-4 were attributed to the hydrophobic effect, whereas steric hindrance or micropore-filling played a main role in the adsorption of antibiotics by F-400 because of its high microporosity. Aside from F-400, similar patterns of pH-dependent adsorption were observed, implying the importance of antibiotic molecular forms to the adsorption process for adsorbents. Increasing the ionic concentration with CaC12 produced particular adsorption characteristics on MWCNT at pH 2.0 and F-400 at pH 8.0, which were attributed to the highly available contact surfaces and molecular sieving, respectively. Its hybrid characteristics incorporating a considerable portion of mesopores and micropores made hypercross linked MN-202 a superior antibiotic adsorbent with high adsorption capacity. Furthermore, the adsorption capacity of MWCNT on the basis of surface area was more advantageous than that of the other adsorbents because MWCNT has a much more compact molecular arrangement. PMID:24218839

Xia, Mingfang; Li, Aimin; Zhu, Zhaolian; Zhou, Qin; Yang, Weiben

2013-07-01

229

Fly ash adsorbents for multi-cation wastewater treatment  

International Nuclear Information System (INIS)

Class “F” fly ash (FA), collected from the Central Heat and Power (CHP) Plant Brasov (Romania), with oxides composition SiO2/Al2O3 over 2.4 proved good adsorbent properties, and was further used for obtaining a new substrate with good adsorption capacity for heavy metals from multi-cation wastewater treatment. Firstly, the new adsorbent was characterized by AFM, XRD, DSC, FTIR and the surface energy was evaluated by contact angle measurements. The experimental data suggested that the new type of substrate is predominant crystalline with highly polar surface. The substrate was used for removing the Pb2+, Cd2+ and Zn2+ cations from mixed solutions. The results show high efficiency and selective adsorption the Pb2+ and Zn2+ cations. The optimized adsorption parameters were further used in thermodynamic and kinetic studies of the adsorption processes. The Langmuir and Freundlich models were used to describe the processes. The pseudo-second order kinetics could well model all the processes, indicating a surface concentration of the adsorption sites with the same order of magnitude as the cation concentrations.

2012-06-15

230

Displacer Effects on Pre-adsorbed Polystyrenes In Nanoporous Silica  

Science.gov (United States)

The addition of low molecular weight displacers has been used to probe the nature of adsorbed polymer chains on surfaces, and we have employed the displacers to understand the adsorption of polystyrene (PS) onto nanopores of silica particles in cyclohexane. When the radius of gyration (Rg) of PS is smaller than the pore radius (Rp) of the nanoporous silica, the displacement behavior of PS on nanopore surfaces is in quantitative agreement with that of PS on flat surfaces. However, when Rg of PS is larger than Rp of nanopores, the addition of displacers after preadsorbing PS in nanopores has increased the surface access of PS by a factor as large as 100% -200%, depending on the relative size ratio of Rg/Rp. On the contrary, when the displacers are mixed with cylcohexane prior to the PS adsorption in small nanopores, the surface access of PS is monotonically dependent of the composition of displacers. This suggests that the larger PS chains adsorbed in smaller pores are kinetically entrapped with severely limited mobility, and the addition of displacers will facilitate the diffusion of PS in nanopores by inducing a weaker surface binding and swelling of the congested PS chains in nanopores.

Ryu, Chang Y.; Kim, Chansu; Batson, Joel; Kumar, Sanat

2007-03-01

231

Adsorbent cartridge for the exhaust of diazo process machines  

International Nuclear Information System (INIS)

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

1982-01-01

232

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

Energy Technology Data Exchange (ETDEWEB)

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

Visa, Maria, E-mail: maria.visa@unitbv.ro [Transilvania University of Brasov, Department Renewable Energy Systems and Recycling, Eroilor 29, 500036 Brasov (Romania)

2012-12-15

233

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

International Nuclear Information System (INIS)

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

1983-10-17

234

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

235

Electron transfer behavior at polyoxometalate-adsorbed alkanethiol self-assembled monolayers  

International Nuclear Information System (INIS)

The interaction between polyoxometalate (POM) anions, SiMo12O404-, and a self-assembled monolayer (SAM) of dodecanethiol (DT) on Au surfaces was investigated using electrochemical methods, X-ray photoelectron spectroscopy, and scanning probe microscopy. The SiMo12O404- ions adsorb on the SAM of DT on Au to form a composite organic-inorganic hybrid layer. The adsorbed SiMo12O404- ion on the SAM layer shows its characteristic redox waves with an electron transfer rate slower than that on a bare Au electrode. The electron transfer behavior at DT-SAM could be regulated by the adsorption of SiMo12O404- depending on the charge of the investigated electroactive species: a significant increase toward a positively charged Ru(NH3)63+ ion, a moderate increase toward a neutral 1,1'-ferrocenedimethanol molecule and a slight decrease toward a negatively charged Fe(CN)63- ion. The effect of the chain length of alkanethiols on the adsorption of SiMo12O404- ion was also investigated: as the chain length decreases, the amount of the adsorbed POM increases and the electron transfer rate through the composite layers increases. The nature of SiMo12O404- ions adsorbed on the SAMs of alkanethiols on Au is discussed in detail.

2011-09-01

236

Electron transfer behavior at polyoxometalate-adsorbed alkanethiol self-assembled monolayers  

Science.gov (United States)

The interaction between polyoxometalate (POM) anions, SiMo 12O 404-, and a self-assembled monolayer (SAM) of dodecanethiol (DT) on Au surfaces was investigated using electrochemical methods, X-ray photoelectron spectroscopy, and scanning probe microscopy. The SiMo 12O 404- ions adsorb on the SAM of DT on Au to form a composite organic-inorganic hybrid layer. The adsorbed SiMo 12O 404- ion on the SAM layer shows its characteristic redox waves with an electron transfer rate slower than that on a bare Au electrode. The electron transfer behavior at DT-SAM could be regulated by the adsorption of SiMo 12O 404- depending on the charge of the investigated electroactive species: a significant increase toward a positively charged Ru(NH 3) 63+ ion, a moderate increase toward a neutral 1,1'-ferrocenedimethanol molecule and a slight decrease toward a negatively charged Fe(CN) 63- ion. The effect of the chain length of alkanethiols on the adsorption of SiMo 12O 404- ion was also investigated: as the chain length decreases, the amount of the adsorbed POM increases and the electron transfer rate through the composite layers increases. The nature of SiMo 12O 404- ions adsorbed on the SAMs of alkanethiols on Au is discussed in detail.

Chu, Yeonyi; Kim, Jandee; Choi, Suhee; Rhee, Choong Kyun; Kim, Jongwon

2011-09-01

237

Removal of gaseous radioiodine with solid adsorbents  

International Nuclear Information System (INIS)

In nuclear power plants only activated impregnated carbon is used to remove airborne radioiodine from exhaust air and off-gas. In reprocessing plants mostly wet washing processes are used for iodine removal. As solid iodine adsorbents, only silver containing materials have been qualified for cleaning the reprocessing off-gases which are poisoned with NOsub(x). Iodine filters with impregnated activated carbon can be designed for removal efficiencies of 99.99% for elemental iodine and 99% for methyl iodide (a typical airborne organic iodine compound) under the most unfavorable operational conditions. From the operational experience it can be concluded that a high bed depth (for example 20-50 cm) together with a residence time of about 1 s will ensure a high performance (>= 99% for CH3131I) and a reasonable time of operation (approx.= 1 a) of a well designed iodine filter with impregnated activated carbon as the adsorbent

1983-05-01

238

Adsorbents for radioactive organic solvent wastes  

International Nuclear Information System (INIS)

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

1984-09-08

239

Non-Equilibrium in Adsorbed Polymer Layers  

CERN Document Server

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

240

Zeolites as alcohol adsorbents from aqueous solutions  

Directory of Open Access Journals (Sweden)

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

Cekova Blagica

2006-01-01

 
 
 
 
241

Magnesium silicates adsorbents of organic compounds  

Science.gov (United States)

Studies were presented on production of highly dispersed magnesium silicate at a pilote scale. The process of silicate adsorbent production involved precipitation reaction using water glass (sodium metasilicate) solution and appropriate magnesium salt, preceded by an appropriate optimization stage. Samples of best physicochemical parameters were in addition modified (in order to introduce to silica surface of several functional groups) using the dry technique and various amounts of 3-isocyanatepropyltrimethoxysilane, 3-thiocyanatepropyltrimethoxysilane, N-phenyl-3-aminopropyltrimethoxysilane. The so prepared samples were subjected to a comprehensive physicochemical analysis. At the terminal stage of studies attempts were made to adsorb phenol from its aqueous solutions on the surface of unmodified and modified magnesium silicates. Particle size distributions were determined using the ZetaSizer Nano ZS apparatus. In order to define adsorptive properties of studied magnesium silicates isotherms of nitrogen adsorption/desorption on their surfaces were established. Efficiency of phenol adsorption was tested employing analysis of post-adsorption solution.

Ciesielczyk, Filip; Krysztafkiewicz, Andrzej; Jesionowski, Teofil

2007-08-01

242

Calculation of elastic diffuse LEED intensities from disordered adsorbates  

Energy Technology Data Exchange (ETDEWEB)

To calculate the diffuse intensity distribution produced by low-energy electrons elasticity scattered from an adsorbate randomly adsorbed on locally identical sites on an otherwise clean crystal surface, and (optionally) to derive from this a Y-function characteristic of the local bonding geometry of the adsorbate.

Saldin, D.K.; Pendry, J.B.

1986-11-01

243

Calculation of elastic diffuse LEED intensities from disordered adsorbates  

International Nuclear Information System (INIS)

To calculate the diffuse intensity distribution produced by low-energy electrons elasticity scattered from an adsorbate randomly adsorbed on locally identical sites on an otherwise clean crystal surface, and (optionally) to derive from this a Y-function characteristic of the local bonding geometry of the adsorbate. (orig.)

1986-11-01

244

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 Ra"2"+ ions in the form of particulates, preferably colloidal. The procedure for adsorbent preparation is described. (J.P.)

1980-01-01

245

Adsorption of Cu(II) to ferrihydrite and ferrihydrite-bacteria composites: Importance of the carboxyl group for Cu mobility in natural environments  

Science.gov (United States)

Bacterially associated iron (hydr)oxide composites are widespread in natural environments, and by analogy with isolated iron (hydr)oxides and bacteria, are important scavengers of dissolved trace-metals. We precipitated ferrihydrite via rapid Fe(III) hydrolysis in the absence and presence of the non-Fe metabolising, Gram-positive bacterium Bacillus subtilis, commonly found in natural waters, soils and sediments. We combined XRD, SEM, BET and Fe K-edge EXAFS to examine the mineralogy, morphology and crystallinity of the ferrihydrite composites. We find that the mineral fraction of the composites is unaltered in primary mineralogy, morphology and crystallinity compared to pure ferrihydrite. We then measured the adsorption of Cu to ferrihydrite and the ferrihydrite-B. subtilis composites as a function of pH and the ferrihydrite:bacteria mass ratio of the composites, and used EXAFS to determine the molecular mechanisms of Cu adsorption. We determine directly for the first time that Cu uptake by ferrihydrite-B. subtilis composites is the result of adsorption to both the ferrihydrite and B. subtilis fractions. Adsorption of Cu by the B. subtilis fraction results in significant Cu uptake in the low pH regime (pH ˜4, ˜20% of [Cu]total) and significantly enhanced Cu uptake in the mid pH regime. This composite sorption behaviour is in stark contrast to pure ferrihydrite, where Cu adsorption is negligible at low pH. Overall, for composites dominated by either ferrihydrite or B. subtilis, the bacterial fraction is exclusively responsible for Cu adsorption at low pH while the ferrihydrite fraction is predominantly responsible for adsorption at high pH. Furthermore, with an increased mass ratio of bacteria, the dominance of Cu adsorption to the bacterial fraction persists into the mid pH regime and extends significantly into the upper pH region. As such, the distribution of the total adsorbed Cu between the composite fractions is a function of both pH and the ferrihydrite:bacteria mass ratio of the composite. EXAFS shows that Cu adsorbs to ferrihydrite as an inner-sphere, (CuO4Hn)n - 6 bidentate edge-sharing complex; and to ferrihydrite composites as an inner-sphere, (CuO5Hn)n - 8 monodentate complex with carboxyl surface functional groups present on the bacterial fraction plus the bidentate edge-sharing complex on the ferrihydrite fraction. Our new results combined with previous work on Cu sorption to bacteria, humic substances and iron (hydr)oxides coated with humics, demonstrate the universal importance of the carboxyl moiety for Cu sorption and mobility in natural environments. Taken together these results show that Cu-carboxyl binding is the predominant mechanism by which Cu interacts with abiotic and biotic organic matter, and provides a ubiquitous control on Cu fate and mobility in natural waters, soils and sediments. Our results indicate that in environments where a significant proportion of iron (hydr)oxides are intimately intermixed with an organic fraction, we must consider Cu sequestration by these composites in addition to pure mineral phases.

Moon, Ellen M.; Peacock, Caroline L.

2012-09-01

246

Evaluation of adsorbents for road runoff treatment  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Six adsorbent materials have been tested to remove the organic pollutants (methyl tert-butyl ether (MTBE) and Naphthalene (Nap)) from road runoff. Compared to red alga, beer draff, semi-organophilic bentonite, and sponge iron, activated carbon (F300) and activated lignite (HOK) are more suitable materials for road runoff treatment. In experiments, both batch and column tests were conducted. The influences of de-icing salt and natural organic matter (NOM) on adsorption have also been considered.

Li, Yang

2013-01-01

247

Curvature Elasticity of an Adsorbed Polymer Layer  

Digital Repository Infrastructure Vision for European Research (DRIVER)

We study theoretically the change of the curvature moduli of a surfactant membrane due to the adsorption of a polymer solution. Using a mean field theory of polymer adsorption, we study both cases of reversible and irreversible polymer adsorption in good and ? solvents. The curvature moduli of the adsorbed polymer layers axe dominated by the short loops that the polymer forms on the membrane. The polymer contribution to the membrane bending modulus is always negative and the polymer contribu...

1997-01-01

248

Adsorbent density impact on gas storage capacities  

Digital Repository Infrastructure Vision for European Research (DRIVER)

In the literature, different approaches, terminologies, concepts and equations are used for calculating gas storage capacities. Very often, these approaches are not well defined, used and/or determined, giving rise to significant misconceptions. Even more, some of these approaches, very much associated with the type of adsorbent material used (e.g., porous carbons or new materials such as COFs and MOFs), impede a suitable comparison of their performances for gas storage applications. We revie...

2013-01-01

249

Vibrational anharmonicity of adsorbates on surfaces  

Digital Repository Infrastructure Vision for European Research (DRIVER)

A methodology for the calculation of anharmonic vibrational frequencies of adsorbates on surfaces is developed. The theoretical method which is used for the description of the vibrational dynamics is the VSCF (vibrational self-consistent field) method. The potential energy surface is computed in a modified fast-VSCF approach which yields a general and system-independent scheme for the calculation of anharmonic vibrational frequencies for large molecules; the method is not restricted to the ap...

2010-01-01

250

Desorption behaviour of regular adsorbed polyampholytic layers  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The desorption behaviour of the diblock polyampholyte PMAA-b-PDMAEMA, poly(methacrylic acid)-block-poly ((dimethylamino)ethyl methacrylate), preadsorbed on silicon substrates was investigated under the influence of several desorption agents. The investigated polyampholyte is known to adsorb in regular structures directly from aqueous solutions onto silicon substrates. While the adsorption process is mainly determined by electrostatic interactions, two kinds of desorption mechanism should be a...

Mahltig, Boris; Gohy, Jean-franc?ois; Je?ro?me, Robert; Pfuetze, G.; Stamm, Manfred

2003-01-01

251

Continuum Elastic Theory of Adsorbate Vibrational Relaxation  

CERN Multimedia

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

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

1997-01-01

252

Characterisation of lignite as an industrial adsorbent  

Energy Technology Data Exchange (ETDEWEB)

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

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

2011-04-15

253

Biological adsorbent for water decontamination from uranium  

International Nuclear Information System (INIS)

A study was made into the capacity of native and heat-denaturated mycelium to adsorb uranium salts from solutions and into the effect of uranium on the growth of the microorganism biomass. The presence of uranium did not inhibit the growth of Penicillium and Aspergillus strains used at a concentration of up to 5x10-4 M/dm3. Uranium added to a nutrient medium produced complexes with phosphorus ions which were adsorbed on the surface of growing hyphae, thus the removal of the mycelium also removed uranium. The results of the experiments with denaturated mycelium of the same strains suggested that uranium was also bound to the biomass with chemical bonds so that mycelium acted as a ''multifunction ion exchanger'' from which adsorbed uranium can be removed step by step by elution. A sorbent of a three-dimensional structure could be prepared from a dried native mycelium using reinforcing resins, which prevented leakage of the biomass. Uranium sorption by biosorbents is a function of the concentration of the cation sorbed and of the pH of the solution. (author)

1978-01-01

254

Activity of Aflatoxins Adsorbents in Poultry Feed  

Directory of Open Access Journals (Sweden)

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

Yasmin Mussaddeq

2000-01-01

255

Moessbauer spectroscopic studies of ferrocene adsorbed on silica gel  

International Nuclear Information System (INIS)

Moessbauer spectra of ferrocene adsorbed on silica gel were measured in order to study the state of adsorption. Ferrocene adsorbed on silica gel tended to oxidize in air and form ferricenium ion. It is assumed that the oxidation of adsorbed ferrocene was caused by surface hydroxyls on the silica gel and O2 in air. It was observed that ferrocene adsorbed weakly at 293 K, although the ferricenium ion adsorbed strongly at 293 K. Thus the adsorption states of ferrocene depend on the experimental condition. (orig.)

1990-07-01

256

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

International Nuclear Information System (INIS)

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

1983-10-17

257

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

2012-12-01

258

Preparation of sodium humate/{alpha}-aluminum oxide adsorbents for flue gas desulfurization  

Energy Technology Data Exchange (ETDEWEB)

A new composite adsorbent of sodium humate (HNa)=alpha-aluminium oxide ({alpha}-Al{sub 2}O{sub 3}) for flue gas desulfurization (FGD) was prepared using the impregnation method. Both the adsorbent of {alpha}-Al{sub 2}O{sub 3} and HNa={alpha}-Al{sub 2}O{sub 3} were characterized by Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), energy dispersive X-ray spectrometer (EDS), and scanning electron microscope (SEM). Desulfurization activity of the adsorbent impregnated with ammonia (NH{sub 4}OH) was investigated in a fixed-bed quartz reactor. Experimental results indicate that HNa, which coats the {alpha}-Al{sub 2}O{sub 3} fibers impregnated with HNa solution, improved the property of {alpha}-Al{sub 2}O{sub 3} support for FGD. On the other hand, the HNa-coating on the adsorbent of HNa/{alpha}-Al{sub 2}O{sub 3} impregnated with NH{sub 4}OH played an important role in enhancing the desulfurization property of the {alpha}-Al{sub 2}O{sub 3}. Due to the strong adsorption capability of HNa, more NH{sub 4}OH was adsorbed in the adsorbent of HNa/{alpha}-Al{sub 2}O{sub 3} the longer a high sulfur dioxide (SO{sub 2}) conversation rate was maintained. In addition, because the desulfurization product was a compound fertilizer consisting of ammonium sulfate ((NH{sub 4}){sub 2}SO{sub 4}), ammonium humate (HNH{sub 4}), and HNa, the recycling use of {alpha}-Al{sub 2}O{sub 3} was also easily achieved. Thus, this study can provide a new cost-effective way to remove SO{sub 2} from flue gas.

Sun, Z.G.; Gao, H.Y.; Hu, G.X.; Li, Y.H. [Shanghai Jiao Tong University, Shanghai (China)

2009-06-15

259

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

Science.gov (United States)

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

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

2012-09-01

260

Novel fungus-titanate bio-nanocomposites as high performance adsorbents for the efficient removal of radioactive ions from wastewater.  

Science.gov (United States)

Reclaimable adsorbents have a critical application in the adsorption of radioactive materials. In this study, the novel bio-nanocomposites comprising fungi and titanate nanotubes are successfully synthesized by a simple and low-cost method. Morphological characterizations and composite mechanism analysis confirm that the composites are sufficiently stable to avoid dust pollution resulting from the titanate nanomaterials. Adsorption experiments demonstrate that the bio-nanocomposites are efficient adsorbents with a saturated sorption capacity as high as 120 mg g(-1) (1.75 meq. g(-1)) for Ba(2+) ions. The results suggest that the bio-nanocomposites can be used as promising radioactive adsorbents for removing radioactive ions from water caused by nuclear leakage. PMID:24287628

Xu, Mingze; Wei, Guodong; Liu, Na; Zhou, Liang; Fu, Chengwei; Chubik, M; Gromov, A; Han, Wei

2014-01-21

 
 
 
 
261

Novel fungus-titanate bio-nanocomposites as high performance adsorbents for the efficient removal of radioactive ions from wastewater  

Science.gov (United States)

Reclaimable adsorbents have a critical application in the adsorption of radioactive materials. In this study, the novel bio-nanocomposites comprising fungi and titanate nanotubes are successfully synthesized by a simple and low-cost method. Morphological characterizations and composite mechanism analysis confirm that the composites are sufficiently stable to avoid dust pollution resulting from the titanate nanomaterials. Adsorption experiments demonstrate that the bio-nanocomposites are efficient adsorbents with a saturated sorption capacity as high as 120 mg g-1 (1.75 meq. g-1) for Ba2+ ions. The results suggest that the bio-nanocomposites can be used as promising radioactive adsorbents for removing radioactive ions from water caused by nuclear leakage.Reclaimable adsorbents have a critical application in the adsorption of radioactive materials. In this study, the novel bio-nanocomposites comprising fungi and titanate nanotubes are successfully synthesized by a simple and low-cost method. Morphological characterizations and composite mechanism analysis confirm that the composites are sufficiently stable to avoid dust pollution resulting from the titanate nanomaterials. Adsorption experiments demonstrate that the bio-nanocomposites are efficient adsorbents with a saturated sorption capacity as high as 120 mg g-1 (1.75 meq. g-1) for Ba2+ ions. The results suggest that the bio-nanocomposites can be used as promising radioactive adsorbents for removing radioactive ions from water caused by nuclear leakage. Electronic supplementary information (ESI) available: The experimental section and supplementary figures are shown in supplementary information. See DOI: 10.1039/c3nr03467d

Xu, Mingze; Wei, Guodong; Liu, Na; Zhou, Liang; Fu, Chengwei; Chubik, M.; Gromov, A.; Han, Wei

2013-12-01

262

Molecular factors in dendritic cell responses to adsorbed glycoconjugates.  

Science.gov (United States)

Carbohydrates and glycoconjugates have been shown to exert pro-inflammatory effects on the dendritic cells (DCs), supporting pathogen-induced innate immunity and antigen processing, as well as immunosuppressive effects in the tolerance to self-proteins. Additionally, the innate inflammatory response to implanted biomaterials has been hypothesized to be mediated by inflammatory cells interacting with adsorbed proteins, many of which are glycosylated. However, the molecular factors relevant for surface displayed glycoconjugate modulation of dendritic cell (DC) phenotype are unknown. Thus, in this study, a model system was developed to establish the role of glycan composition, density, and carrier cationization state on DC response. Thiol modified glycans were covalently bound to a model protein carrier, maleimide functionalized bovine serum albumin (BSA), and the number of glycans per BSA modulated. Additionally, the carrier isoelectric point was scaled from a pI of ?4.0 to ?10.0 using ethylenediamine (EDA). The DC response to the neoglycoconjugates adsorbed to wells of a 384-well plate was determined via a high throughput assay. The underlying trends in DC phenotype in relation to conjugate properties were elucidated via multivariate general linear models. It was found that glycoconjugates with more than 20 glycans per carrier had the greatest impact on the pro-inflammatory response from DCs, followed by conjugates having an isoelectric point above 9.5. Surfaces displaying terminal ?1-2 linked mannose structures were able to increase the inflammatory DC response to a greater extent than did any other terminal glycan structure. The results herein can be applied to inform the design of the next generation of combination products and biomaterials for use in future vaccines and implanted materials. PMID:24746228

Hotaling, Nathan A; Cummings, Richard D; Ratner, Daniel M; Babensee, Julia E

2014-07-01

263

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

International Nuclear Information System (INIS)

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

2008-04-01

264

Tight-binding model of adsorbate structures  

International Nuclear Information System (INIS)

Tight-binding calculations are presented of the ground state energies of metal atoms absorbed on the surface of the same or similar metals. We consider rows and clusters of adsorbate, and find significant energy variations as a function of the number of the atoms. Results are presented for the (001) face both for fcc and bcc crystals. General results that are applicable for any elemental fcc or bcc crystal are obtained in the present paper. We include only s-wave tight-binding orbits in the nearest neighbor approximation. copyright 1999 The American Physical Society

1999-05-01

265

?-radiolysis of methane adsorbed on ?-alumina  

International Nuclear Information System (INIS)

Previous studies showed that methane adsorbed on ?-alumina undergoes radiolysis to form chemisorbed precursor species. These decompose when heated to give C1-C3 alkane and alkene products together with hydrogen. The present study uses nitric oxide, nitrous oxide, sulphur hexafluoride, oxygen and carbon dioxide as additives to interfere with product formation, and so allows probable structures to be deduced for each precursor. Both alkane and alkene precursors involve alkylaluminium groups which decompose by homolytic fission of the Al-C bond. The alkane precursor has an accessible hydroxide ion from which a hydrogen atom can be extracted during desorption, whereas the alkene precursor does not. (author)

1979-01-01

266

Switching photochromic molecules adsorbed on optical microfibres.  

Science.gov (United States)

The internal state of organic photochromic spiropyran molecules adsorbed on optical microfibres is optically controlled and measured by state-dependent light absorption. Repeated switching between the states is achieved by exposure to the evanescent field of a few nanowatts of light guided in the microfibre. By adjusting the microfibre evanescent field strength the dynamic equilibrium state of the molecules is controlled. Time-resolved photoswitching dynamics are measured and modelled with a rate equation model. We also study how many times the photochromic system can be switched before undergoing significant photochemical degradation. PMID:22714300

Wiedemann, U; Alt, W; Meschede, D

2012-06-01

267

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

268

Spectroscopy and dynamics of orientationally structured adsorbates  

CERN Document Server

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

Rozenbaum, V M

2002-01-01

269

Detecting Adsorbed Sulfate and Phosphate on Nanophase Weathering Products on Mars  

Science.gov (United States)

Characterizing the mineralogy and chemistry of aqueous alteration phases on the martian surface is essential for understanding past aqueous processes because the types of secondary phases present and their chemical compositions tell us about the environments in which they formed. Orbital mid-infrared data and in-situ mineralogical and chemical data from the martian surface indicate that Si/Al- and Fe-bearing nanophase weathering products are widespread, including allophane and nanophase ferric oxide (npOx), which includes any combination of superparamagnetic hematite and goethite, ferrihydrite, schwertmannite, akaganeite, iddingsite, and palagonite (altered basaltic glass) [Morris et al., 2006; Michalski et al., 2006; Rampe et al., in press]. These weathering products have larger surface areas and variable surface charge and can adsorb anions and cations onto their surfaces. Some anions, such as sulfate and phosphate, specifically chemically adsorb onto mineral/mineraloid surfaces so that these complexes are covalently bonded and form ligands. Nanophase weathering products on Earth can specifically adsorb up to a few weight percent to a few tens of weight percent phosphate and sulfate, respectively [Parfitt and Smart, 1978; Jara et al., 2006]. Phosphate and sulfate have been identified in martian rocks and soils in abundances of up to ~5 wt.% and ~30 wt.%, respectively [Gellert et al., 2006; Ming et al., 2006], and it has been suggested that phosphate and sulfate ions may be adsorbed on nanophase weathering products on the martian surface [Greenwood and Blake, 2006; Morris et al., 2006]. What is relatively unknown is how to use in-situ and orbital instruments on Mars to determine if these ions are present as discrete minerals or adsorbed onto the surfaces of weathering products. We adsorbed phosphate and sulfate onto allophane surfaces in the laboratory. Here, we present laboratory measurements of phosphate- and sulfate-adsorbed allophane to compare to in-situ observations from CheMin and SAM on Mars Science Laboratory and remote observations from OMEGA, CRISM, and TES. CheMin- and OMEGA/CRISM-relevant laboratory measurements reveal minor differences between ion-free and ion-adsorbed allophane that would not be detectable by those instruments. However, SAM-relevant evolved gas analyses of sulfate-adsorbed allophane show a high-temperature (>950 C) release related to SO2 gas. The release at high temperatures suggests that sulfate was strongly bonded to the allophane surface. TES-relevant thermal-infrared emission spectra of phosphate- and sulfate-adsorbed allophane display broad absorptions near 1000 cm-1 from P-O and S-O vibrations. Our laboratory measurements suggest that ions adsorbed onto weathering product surfaces may be recognized on Mars with in-situ measurements by SAM on MSL and with orbital measurements from TES. Future experiments will include similar laboratory measurements of phosphate- and sulfate-adsorbed nanophase ferric oxides.

Rampe, E. B.; Morris, R. V.

2012-12-01

270

Adsorption characteristics of water vapor on honeycomb adsorbents  

Science.gov (United States)

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

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

2011-10-01

271

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

272

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

International Nuclear Information System (INIS)

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

1989-01-01

273

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

Directory of Open Access Journals (Sweden)

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

Bondar I.V.

2012-08-01

274

Binary mixture adsorbed in a slit pore: Field-induced population inversion near the bulk instability.  

Science.gov (United States)

The recently proposed method for modulating through an external field the composition of a binary fluid mixture adsorbed in a slit pore is discussed. The population inversion near the bulk (demixing) instability is first analyzed in the case of a symmetric mixture of nonadditive hard spheres, without field. It is next investigated for a mixture comprising dipolar particles subject to an external field. The influence of several factors on the adsorption curves including bulk composition, pore width, field direction, polarizability versus permanent dipoles, and temperature on this field induced population inversion is shown by Monte Carlo simulation. PMID:20866815

Brunet, C; Malherbe, J G; Amokrane, S

2010-08-01

275

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

276

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)

2007-10-01

277

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

International Nuclear Information System (INIS)

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

1986-01-01

278

The adsorption of water isotopomers on carbon adsorbents  

International Nuclear Information System (INIS)

Adsorption isotherms in the range 50-80 Deg C were measured by gas chromatography, and isosteric adsorption heats of isotopomers of water were calculated in the range of low fillings at two activated carbons (Norit and FAS) with close volume of micropores (0.38 and 0.37 cm3/g), but various surface chemistry (AC Norit with hydrophilic surface and AC FAS with hydrophobic one). Adsorption of H2O and D2O at AC Norit exceeds adsorption at AC FAS at all equilibrium pressures. Adsorption isotherms of H2O and D2O at every adsorbents are close, but some excess of isotherms and adsorption heats of D2O as compared with H2O ones observes. It is connected with the differences in adsorbate-adsorbent and adsorbate-adsorbate interactions as well as with the structure of molecules of adsorbates

2009-02-01

279

Separation and Recovery of Tetramethyl Ammonium Hydroxide with Zeolitic Adsorbents  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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...

2010-01-01

280

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.

2010-03-01

 
 
 
 
281

Adsorbate/absorbate interactions with organic ferroelectric polymers  

International Nuclear Information System (INIS)

We discuss the interactions of adsorbates with the organic ferroelectric copolymer poly(vinylidene fluoride (PVDF)-trifluoroethylene (TrFE)). Range of molecular adsorbates is discussed from the smaller polar molecules like water, which is small enough to both adsorb and absorb, to the larger macrocyclic metal-organic metal phthalocyanines. The changes in local dipole orientation may affect the strength of the coupling between adsorbate or absorbate and the copolymer poly(vinylidene fluoride-trifluoroethylene). The interface dipole interactions may also affect device properties. The dipole interactions are implicated at the interface between copper phthalocyanine and poly(vinylidene fluoride with trifluoroethylene) affecting the band offsets and the diode properties.

2009-08-01

282

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

283

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 been shown as an efficient adsorbent, in which VOCs in low content streams are first concentrated and desorbed in a second step with higher concentrations suitable for oxidation. The advantages of th...

2006-01-01

284

NOx Removal and Effect of Adsorbate-Adsorbate Interactions  

DEFF Research Database (Denmark)

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

Khan, Tuhin Suvra

2013-01-01

285

Characterization of adsorbents from local carbonaceous materials  

Energy Technology Data Exchange (ETDEWEB)

Analyzes physical and chemical properties of an adsorbent for water purification produced from brown coal Winkler gasification ash. A flowsheet for industrial production of activated carbon from this carbon containing ash is provided. Properties of the activated Winkler carbon are compared to those of unprocessed Winkler ash, further to brown coal high temperature coke and to an additional water purification carbon. Properties compared include pore distribution, electrical resistivity, content of functional groups, density, pore volume, aromaticity, C/H relation, volatile content and mean molecular mass. A structural model of a Winkler ash particle is also proposed. It is concluded that hard and semi-hard carbonaceous materials including both brown coal coke and Winkler ash are suitable for activation after mechanical preparation. 25 refs.

Huschenbett, R.; Kuemmel, R.; Winkler, F.; Moebius, R. (Technische Hochschule Carl Schorlemmer, Leuna-Merseburg (German Democratic Republic). Sektion Verfahrenstechnik)

1990-08-01

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

The condensation of water on adsorbed viruses.  

Science.gov (United States)

The wetting and dewetting behavior of biological nanostructures and to a greater degree single molecules is not well-known even though their contact with water is the basis for all biology. Here, we show that environmental electron microscopy (EM) can be applied as a means of imaging the condensation of water onto viruses. We captured the formation of submicrometer water droplets and filaments on single viral particles by environmental EM and by environmental transmission EM. The condensate structures are compatible with capillary condensation between adsorbed virus particles and with known droplet shapes on patterned surfaces. Our results confirm that such droplets exist down to <50 nm. The viruses preserved their shape after a condensation/evaporation cycle as expected from their stability in air and water. Moreover we developed procedures that overcome problems of beam damage and of resolving structures with a low atomic number. PMID:24160759

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

2013-11-26

288

In vitro hydroxyapatite adsorbed salivary proteins  

International Nuclear Information System (INIS)

In spite of the present knowledge about saliva components and their respective functions, the mechanism(s) of pellicle and dental plaque formation have hitherto remained obscure. This has prompted recent efforts on in vitro studies using hydroxyapatite (HA) as an enamel model. In the present study salivary proteins adsorbed to HA were extracted with TFA and EDTA and resolved by 2D electrophoresis over a pH range between 3 and 10, digested, and then analysed by MALDI-TOF/TOF mass spectrometry and tandem mass spectrometry. Nineteen different proteins were identified using automated MS and MS/MS data acquisition. Among them, cystatins, amylase, carbonic anhydrase, and calgranulin B, were identified

2004-07-23

289

Utilization of Waste Eggshells as Humidity Adsorbent  

Directory of Open Access Journals (Sweden)

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

S. Limsuwan

2011-01-01

290

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

291

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

International Nuclear Information System (INIS)

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

1997-06-03

292

Film morphology and orientation of amino silicone adsorbed onto cellulose substrate  

International Nuclear Information System (INIS)

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

2009-07-30

293

Outer-sphere Pb(II) adsorbed at specific surface sites on single crystal ??-alumina  

Science.gov (United States)

Solvated Pb(II) ions were found to adsorb as structurally well-defined outer-sphere complexes at specific sites on the ??-Al2O3 (0001) single crystal surface, as determined by grazing-incidence X-ray absorption fine structure (GI-XAFS) measurements. The XAFS results suggest that the distance between Pb(II) adions and the alumina surface is approximately 4.2 A??. In contrast, Pb(II) adsorbs as more strongly bound inner-sphere complexes on ??-Al2O3 (1102). The difference in reactivities of the two alumina surfaces has implications for modeling surface complexation reactions of contaminants in natural environments, catalysis, and compositional sector zoning of oxide crystals.

Bargar, J. R.; Towle, S. N.; Brown, Jr. , G. E.; Parks, G. A.

1996-01-01

294

Electron transfer behavior at polyoxometalate-adsorbed alkanethiol self-assembled monolayers  

Energy Technology Data Exchange (ETDEWEB)

The interaction between polyoxometalate (POM) anions, SiMo{sub 12}O{sub 40}{sup 4-}, and a self-assembled monolayer (SAM) of dodecanethiol (DT) on Au surfaces was investigated using electrochemical methods, X-ray photoelectron spectroscopy, and scanning probe microscopy. The SiMo{sub 12}O{sub 40}{sup 4-} ions adsorb on the SAM of DT on Au to form a composite organic-inorganic hybrid layer. The adsorbed SiMo{sub 12}O{sub 40}{sup 4-} ion on the SAM layer shows its characteristic redox waves with an electron transfer rate slower than that on a bare Au electrode. The electron transfer behavior at DT-SAM could be regulated by the adsorption of SiMo{sub 12}O{sub 40}{sup 4-} depending on the charge of the investigated electroactive species: a significant increase toward a positively charged Ru(NH{sub 3}){sub 6}{sup 3+} ion, a moderate increase toward a neutral 1,1'-ferrocenedimethanol molecule and a slight decrease toward a negatively charged Fe(CN){sub 6}{sup 3-} ion. The effect of the chain length of alkanethiols on the adsorption of SiMo{sub 12}O{sub 40}{sup 4-} ion was also investigated: as the chain length decreases, the amount of the adsorbed POM increases and the electron transfer rate through the composite layers increases. The nature of SiMo{sub 12}O{sub 40}{sup 4-} ions adsorbed on the SAMs of alkanethiols on Au is discussed in detail.

Chu, Yeonyi [Department of Chemistry, Chungbuk National University, Cheongju, Chungbuk 361-763 (Korea, Republic of); Kim, Jandee [Department of Chemistry, Chungnam National University, Daejeon 305-764 (Korea, Republic of); Choi, Suhee [Department of Chemistry, Chungbuk National University, Cheongju, Chungbuk 361-763 (Korea, Republic of); Rhee, Choong Kyun, E-mail: ckrhee@cnu.ac.kr [Department of Chemistry, Chungnam National University, Daejeon 305-764 (Korea, Republic of); Graduate School of Analytical Science and Technology, Chungnam National University, Daejeon 305-764 (Korea, Republic of); Kim, Jongwon, E-mail: jongwonkim@chungbuk.ac.kr [Department of Chemistry, Chungbuk National University, Cheongju, Chungbuk 361-763 (Korea, Republic of)

2011-09-01

295

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

CERN Multimedia

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

Dabo, Ismaila

2012-01-01

296

Cell for studying electron-adsorbed gas interactions  

International Nuclear Information System (INIS)

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

1967-01-01

297

Adsorption and adsorbate-induced restructuring: A LEED perspective  

Energy Technology Data Exchange (ETDEWEB)

The history of the surface crystallography of adsorbates on single crystals is reviewed, with emphasis on the development and contributions of low-energy electron diffraction (LEED). Highlighted aspects include: progress in LEED instrumentation and theory; atomic and molecular adsorption on metals and semiconductors; coadsorption; disordered overlayers; adsorbate-induced relaxations and reconstructions; and cluster-like bonding

Van Hove, M.A.; Somorjai, G.A. (Materials Sciences Division, Lawrence Berkeley Laboratory, and Department of Chemistry, University of California, Berkeley CA (United States))

1994-01-01

298

Metal adsorbent for alkaline etching aqua solutions of Si wafer  

International Nuclear Information System (INIS)

High performance adsorbent is expected to be synthesized for the removal of Ni and Cu ions from strong alkaline solution used in the surface etching process of Si wafer. Fibrous adsorbent was synthesized by radiation-induce emulsion graft polymerization onto polyethylene nonwoven fabric and subsequent amination. The reaction condition was optimized using 30 L reaction vessel and nonwoven fabric, 0.3 m width and 18 m long. The resulting fibrous adsorbent was evaluated by 48 wt% NaOH and KOH contaminated with Ni and Cu ions, respectively. The concentration levels of Ni and Cu ions was reduced to less than 1 ?g/kg (ppb) at the flow rate of 10 h?1 in space velocity. The life of adsorbent was 30 times higher than that of the commercialized resin. This novel adsorbent was commercialized as METOLATE® since the ability of adsorption is remarkably higher than that of commercial resin used practically in Si wafer processing. - Highlights: ? Adsorbent was synthesized by radiation-induced emulsion graft polymerization. ? Degree of grafting reached 120% at the pre-irradiation of 50 kGy. ? The resulting adsorbent removed Ni and Cu ion in strong alkaline solution. ? Adsorbent was commercialized for filter of Si wafer etchant.

2012-08-01

299

Synthesis of new adsorbents for Mo as an RI generator  

International Nuclear Information System (INIS)

Technetium-99m is widely used in the world for the purpose of diagnosis in nuclear medicine. The 99mTc is obtained from the parent nuclide of 99Mo adsorbed in a generator. Synthesis of Zr-based inorganic polymer, which has extremely high adsorbability of Mo and is applicable to the 99Mo product of low specific activity, was attempted. Five kinds of the precursors for Zr-based-polymer adsorbents were prepared by the hydrolysis of ZrCl4 and the reactions between ZrCl4 and poly (vinyl alcohol), isopropyl alcohol, ethylene glycol or glycerol. These precursors were converted into adsorbents by heating in Ar gas flow. Their structures were presumed from the pyrolysis behavior. Adsorption capacities of Mo of these adsorbents were dependent on the number of Cl atoms bonded to Zr atom in the molecules. It was suggested that the adsorption of Mo to these adsorbents was proceeded by chemical reaction between two neighboring Zr-Cl bonds and MoO42-. The adsorbent prepared from ZrCl4 and isopropyl alcohol showed the highest adsorption capacity of Mo (about 250 mg/g adsorbent) and 99mTc yield (about 80%) in eluant. (author)

1996-10-01

300

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

 
 
 
 
301

Distributions of uranium adsorbed from seawater in spherical polyacrylamidoxime chelating resins  

International Nuclear Information System (INIS)

Distributions of metals adsorbed from seawater in spherical polyacrylamidoxime chelating resins were measured by X-ray micro-analyzer. Distributions of uranium in adsorbents were different according to their gel structure or porosity. In the case of adsorbents with low swelling tendencies, uranium was adsorbed only in the superficial layers of the adsorbents. The amount of adsorbed uranium increased with increasing of contact time, but no uranium was detected in the center of adsorbent even after 331 days. Iron was adsorbed only in the surface layer. Magnesium was detected almost uniformly in all parts of adsorbent. Copper and zinc were detected very little. (author)

1983-10-17

302

Processing method and device for iodine adsorbing material  

Energy Technology Data Exchange (ETDEWEB)

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

Watanabe, Shin-ichi; Shiga, Reiko

1997-03-18

303

Flow boundary conditions for chain-end adsorbing polymer blends.  

Science.gov (United States)

Using the phenol-terminated polycarbonate blend as an example, we demonstrate that the hydrodynamic boundary conditions for a flow of an adsorbing polymer melt are extremely sensitive to the structure of the epitaxial layer. Under shear, the adsorbed parts (chain ends) of the polymer melt move along the equipotential lines of the surface potential whereas the adsorbed additives serve as the surface defects. In response to the increase of the number of the adsorbed additives the surface layer becomes thinner and solidifies. This results in a gradual transition from the slip to the no-slip boundary condition for the melt flow, with a nonmonotonic dependence of the slip length on the surface concentration of the adsorbed ends. PMID:16178621

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

2005-09-01

304

Effect of dissolved oxygen on phenols breakthrough from GAC adsorbers  

Energy Technology Data Exchange (ETDEWEB)

The study demonstrates that molecular oxygen plays an important role in the adsorption of organic compounds from water by activated carbon. It was determined that the adsorptive capacity of granular activated carbon (GAC) for o-cresol can increase by almost 200% as a result of the presence of molecular oxygen in the test environment (oxic conditions). This increase in adsorptive capacity is not due to biological activity but can be totally attributed to the polymerization of o-cresol on the carbon surface under oxic conditions. The rate of adsorbate polymerization is such that the presence of molecular oxygen does not influence adsorption kinetics during the first 12 hours of adsorbent-adsorbate contact. However, the concentration of dissolved oxygen in the feed to a GAC adsorber can significantly influence the breakthrough of adsorbate. (Copyright (c) 1992 IAWPRC.)

Vidic, R.D.; Suidan, M.T.

1992-01-01

305

Kinetic regimes of polyelectrolyte exchange between the adsorbed state and free solution  

Science.gov (United States)

We studied the exchange between the adsorbed state and free solution when polyelectrolyte chains, adsorbed to a solid surface of opposite charge, were displaced by chains of higher charge density. Metastable states of surface composition were extremely long-lived (>2-3 days). The system was a family of poly(1,4 vinyl)pyridines (PVP) with different fractions of charged segments (14%, 48%, and 98% quaternized and the same degree of polymerization); samples were exposed sequentially from aqueous D2O solution to a single silicon oxide substrate at pH where the surface carried a large negative charge (pH=9.2 or 10.5). Measurements were based on Fourier transform infrared spectroscopy in attenuated total reflection (FTIR-ATR). As a first conclusion, we found charge of adsorbed polymer to be conserved during extended exchange times, suggesting that charge at the surface (not mass adsorbed) regulated the dynamics of adsorption and desorption. Except at the highest ionic strength charge of polymer at the surface during the displacement process considerably exceeded that for the initially-adsorbed layer, suggesting an intermediate state in which newly-adsorbed chains were more extended from the surface and not yet equilibrated in their conformations. Second, we concluded that desorption was the rate-limiting step in adsorption-desorption, since the desorption rate responded more to changes of ionic strength than did the adsorption rate onto previously-adsorbed polymer. Ionic strength appeared to modulate the intensity of sticking to the surface. Third, we found that the initial stages of desorption obeyed a simple functional form, exponential in the square root of elapsed time. This is conclusively slower than a first-order kinetic process and suggests that desorption in this polyelectrolyte system was diffusion-controlled during the initial stages. It is the same functional form observed for flexible polymers in nonpolar solvents. Fourth, we concluded that at relatively low concentration of salts desorption proceeded in two stages; one subpopulation of adsorbed chains desorbed relatively quickly, with a rate exponential in the square root of time, and a second subpopulation was so much slower to be desorb that it appeared to be kinetically frozen at the surface. The higher the ionic strength, the less the polymer was kinetically frozen and this effect disappeared entirely for the highest ionic strength. The interpretation that the kinetically-frozen states reflected conformational heterogeneities within the adsorbed layer was supported by direct measurements of the dichroic ratio of adsorbed pyridinium rings. Finally, a new kinetic regime was observed at the highest salt concentrations, in which the exchange was inhibited by worsened solubility of the displaced molecules. It is significant that this regime began at salt concentrations significantly below the point of bulk insolubility. Since most organic polyelectrolytes may be considered to be a copolymer of polar charged units and hydrophobic uncharged units, this effect is expected to be general.

Sukhishvili, Svetlana A.; Granick, Steve

1998-10-01

306

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

Science.gov (United States)

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

Sheshmani, Shabnam; Ashori, Alireza; Hasanzadeh, Saeed

2014-07-01

307

Development of a simplified separation process of trivalent minor actinides from fission products using novel R-BTP/SiO2-P adsorbents  

International Nuclear Information System (INIS)

From a viewpoint of direct separation of trivalent minor actinides (MA: Am, Cm etc.) from fission products (FP) including rare earths (RE) in high level radioactive liquid waste, the authors have developed a simplified separation process using a single column packed with novel extraction adsorbents. Attention was paid to a new type of nitrogen-donor ligand, R-BTP (2,6-bis(5,6-dialkyl-1,2,4-triazin-3-yl)pyridine, R: alkyl group) as an extractant because it has higher extraction selectivity for Am(III) than RE(III). Since the R-BTP ligands show different properties such as adsorbability and stability when they have different alkyl groups, several R-BTP extraction adsorbents were prepared by impregnating the R-BTP ligands with different alkyl groups (isohexyl-, isoheptyl- and cyheptyl-BTP) into a porous silica/polymer composite support (SiO2-P particles). This work investigated: (1) fundamental properties of the synthesized R-BTP/SiO2-P adsorbents, (2) adsorption and desorption properties of Am and FP in nitric acid solution and water using the adsorbents in a batch experiment, (3) radiolytic and chemical stabilities of the adsorbents, and (4) the possibility for developing a simplified separation process of MA using the most promising adsorbent (isohexyl-BTP/SiO2-P) under temperature control between 25 and 50degC. (author)

2012-01-01

308

DBPs removal in GAC filter-adsorber.  

Science.gov (United States)

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

Kim, Jinkeun; Kang, Byeongsoo

2008-01-01

309

Directed random walk in adsorbed monolayer  

CERN Document Server

We study the dynamics of a tracer particle, which performs a totally directed random walk in an adsorbed monolayer composed of mobile hard-core particles undergoing continuous exchanges with a vapour phase. In terms of a mean-field-type approach, based on the decoupling of the tracer-particle-particle correlation functions into the product of pairwise, tracer-particle correlations, we determine the density profiles of the monolayer particles, as seen from the stationary moving tracer, and calculate its terminal velocity, V_{tr}. In the general case the latter is determined implicitly, as the solution of a certain transcendental equation. In two extreme limits of slow and fast monolayer particles diffusion, we obtain explicit asymptotic forms of V_{tr}. We show next that the density profile in the monolayer is strongly inhomogeneous: In front of the stationary moving tracer the local density is higher than the average value, \\rho_L, and approaches \\rho_L as an exponential function of the distance from the trac...

Bénichou, O; Moreau, M; Oshanin, G

1999-01-01

310

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

1994-07-04

311

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

312

Magnetic Fe3O4@C nanoparticles as adsorbents for removal of amoxicillin from aqueous solution.  

Science.gov (United States)

In the present study, powder activated carbon (PAC) combined with Fe(3)O(4) magnetite nanoparticles (MNPs) were used for the preparation of magnetic composites (MNPs-PAC), which was used as an adsorbent for amoxicillin (AMX) removal. The properties of magnetic activated carbon were characterized by scanning electron microscopy, transmission electron microscopy, X-ray diffraction, Brunaeur, Emmett and Teller and vibrating sample magnetometer. The operational factors affecting adsorption such as pH, contact time, adsorbent dosage, initial AMX concentration and temperature were studied in detail. The high surface area and saturation magnetization for the synthesized adsorbent were found to be 671.2 m(2)/g and 6.94 emu/g, respectively. The equilibrium time of the adsorption process was 90 min. Studies of adsorption equilibrium and kinetic models revealed that the adsorption of AMX onto MNPs-PAC followed Freundlich and Langmuir isotherms and pseudo-second-order kinetic models. The calculated values of the thermodynamic parameters, such as ?G°, ?H° and ?S° demonstrated that the AMX adsorption was endothermic and spontaneous in nature. It could be concluded that MNPs-PAC have a great potential for antibiotic removal from aquatic media. PMID:24434981

Kakavandi, Babak; Esrafili, Ali; Mohseni-Bandpi, Anoushiravan; Jonidi Jafari, Ahmad; Rezaei Kalantary, Roshanak

2014-01-01

313

Characterization of mixed alcohol monolayers adsorbed onto a Au(111) electrode using electro-fluorescence microscopy.  

Science.gov (United States)

A single-crystal Au(111) electrode modified with an adsorbed layer of 1-octadecanol (C18OH) or oleyl alcohol (OLA) in pure or mixed composition was characterized using electrochemical and in situ fluorescence microscopy. Cyclic voltammetry and differential capacitance measurements revealed a repeatable, potential-induced adsorption/desorption process of the surfactant to/from the electrode surface while charge density and film pressure measurements indicated quasi-ideal mixing of the two adsorbed alcohols. A layer less defective than pure C18OH was created with incorporated OLA. Optical characterization was accomplished using epi-fluorescence microscopy combined with electrochemistry (electro-fluorescence microscopy) through the incorporation of two fluorescent probes into the adsorbed surfactant layer. Since molecular luminescence is quenched by a nearby metal, fluorescence was only observed when the fluorescent dye/alcohol layers were desorbed and therefore separated from the metal surface. When desorbed, the structure of the alcohol layers were similar in character, revealing aggregated features which did not change in morphology over numerous desorption/re-adsorption cycles. We have also used the electro-fluorescence technique to estimate the distance separating the metal and desorbed surfactant and believe that the molecules are displaced from the electrode surface by a distance not more than 40 nm. PMID:16649810

Shepherd, Jeff L; Bizzotto, Dan

2006-05-01

314

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

Directory of Open Access Journals (Sweden)

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

G. Pirlo

2010-04-01

315

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

Hanna M. Kowalczy?ska

2012-01-01

316

FTIR spectroscopy of hydrogen, carbon monoxide, and methane adsorbed and co-adsorbed on zinc oxide  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Adsorption of dihydrogen, carbon monoxide and methane, and co-adsorption of H2/CO, H2/CH4 and CO/CH4 on zinc oxide was studied by means of Fourier transform infrared spectroscopy. Besides the already known dissociation of dihydrogen and molecular adsorption of CO, methane was found to be adsorbed molecularly on coordinatively unsaturated Zn2+ ions. Adsorption lowers the CH4 symmetry from Td to C3v, which is reflected in activation of the v1 (symmetric stretching) mode and discrete frequency s...

2001-01-01

317

Surface-porous carbon adsorbents for gas chromatography  

Energy Technology Data Exchange (ETDEWEB)

The purpose of this work was to study the chromatographic characteristics of surface-porous carbon adsorbents. Model gaseous mixtures (carbon dioxide + nitrogen, methane + nitrogen) were separated with the aid of the experimental adsorbents in the same column and under the same conditions. The results of the chromatographic investigations were used for determining the peak halfwidths, retention volumes, and separation criteria of the gases, and the heights equivalent to a theoretical plate corresponding to given flow rates of the carrier gas. The use of surface-porous adsorbents based on inorganic carbon compounds was found to reduce the time of chromatographic analysis without adverse effects on the separating power under the same conditions.

Ivakhnyu, G.K.; Babkin, O.E.; Ivanova, G.A.; Vorozhbitova, L.N.; Fedorov, N.F.

1987-09-10

318

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.)

1997-10-01

319

Two-dimensional semiconducting nanostructures based on single graphene sheets with lines of adsorbed hydrogen atoms  

Digital Repository Infrastructure Vision for European Research (DRIVER)

It is shown that lines of adsorbed hydrogen pair atoms divide the graphene sheet into strips and form hydrogen-based superlattice structures (2HG-SL). We show that the forming of 2HG-SL drastically changes the electronic properties of graphene from semimetal to semiconductor. The electronic spectra of "zigzag" (n,0) 2HG-SL is similar to that of (n,0) carbon nanotubes and have a similar oscillation of band gap with number n, but with non-zero minimal values. The composite dua...

Chernozatonskii, Leonid A.; Sorokin, Pavel B.; Bruning, Jochen W.

2007-01-01

320

Application of a new adsorbent for fluoride removal from aqueous solutions  

International Nuclear Information System (INIS)

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

2013-12-15

 
 
 
 
321

Application of a new adsorbent for fluoride removal from aqueous solutions  

Energy Technology Data Exchange (ETDEWEB)

Highlights: • A new adsorbent has been prepared. • The adsorbent is non-toxic and easy to synthesize. • HBO{sub 1} has displayed best capacity for the removal of fluoride. • Unlike most adsorbents, HBO{sub 1} is suitable for the removal of fluoride from water. • The process of removal has been optimized. -- Abstract: Hydrous bismuth oxides (HBOs) have been investigated as a possible adsorbent for fluoride removal from water. Apart from bismuth trioxide (Bi{sub 2}O{sub 3}) compound, three additional HBOs, named as HBO{sub 1}, HBO{sub 2}, and HBO{sub 3} were synthesized in the laboratory and examined for their relative potentials for fluoride removal from aqueous solutions. HBO{sub 1} was observed to have highest fluoride removal at 10 mg/L initial concentration in aqueous environment. Among competitive anions, sulfate and chloride affect the fluoride removal by HBO{sub 1} more adversely than bicarbonate. Characterization of HBOs using X-ray diffraction (XRD) pattern analyses indicated crystalline structures, and the broad chemical composition of materials showed successive increase of Bi(OH){sub 3} from HBO{sub 1} to HBO{sub 3}, with decrease of BiOCl in the same order. Fourier Transform Infrared (FTIR) spectroscopy analyses indicated presence of Bi-O bond and successively increasing number of peaks corresponding to OH ion from HBO{sub 1} to HBO{sub 3}. Scanning Electron Microscopic (SEM) images of HBOs show rough and porous structure of the materials. Presence of higher proportion of chloride compound in HBO{sub 1} with respect to others appears to be the factor responsible for its better performance in fluoride removal from aqueous solutions.

Srivastav, Arun Lal [Department of Applied Chemistry, Indian Institute of Technology (Banaras Hindu University), Varanasi 221005 (India); Singh, Prabhat K. [Department of Civil Engineering, Indian Institute of Technology (Banaras Hindu University), Varanasi 221005 (India); Srivastava, Varsha [Department of Applied Chemistry, Indian Institute of Technology (Banaras Hindu University), Varanasi 221005 (India); Sharma, Yogesh C., E-mail: ysharma.apc@itbhu.ac.in [Department of Applied Chemistry, Indian Institute of Technology (Banaras Hindu University), Varanasi 221005 (India)

2013-12-15

322

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.

Khairil

2011-11-01

323

Effect of chemical additives on biomass deposition onto beaded adsorbents.  

Science.gov (United States)

Common limitations encountered during the direct recovery of bioproducts from an unclarified feedstock are related to the presence of biomass in such processing systems. Biomass-related effects can be described as biomass-to-support deposition and cell-to-cell aggregation. In this work, a number of chemical additives were screened for their ability to inhibit either biomass deposition, cell aggregation, or a combination of both effects. Several interacting pairs were screened. These were composed of (i) a commercial chromatographic matrix harbouring a variety of ligand types and (ii) intact yeast cells - as a model biomass type. Studies were performed based on partitioning tests, colloid deposition experiments, and sorption performance studies in expanded beds. Results indicated that the coating of anion-exchanger beads with the synthetic polymer PVP 360 alleviated biomass deposition and consequently restored EBA process performance. This behaviour correlated well with calculations performed according to the XDLVO approach: the secondary (interaction) free energy pockets decreased from -230 kT to -100 kT in the absence and in the presence of PVP 360, respectively. Experiments performed in parallel demonstrated that total binding capacity for the model protein (BSA) - under dynamic conditions - remained almost constant (? 55.7 kg m(-3)). Other combinations of additives and adsorbents were tested. However, no solution chemistry was able to inhibit biomass deposition onto strong (composite) ion exchangers. Moreover, yeast cell deposition was only marginally decreased when hydrophobic interaction and pseudo-affinity supports were explored. The utilization of non-toxic polymers could help to avoid detrimental biomass deposition during expanded bed adsorption of bioproducts and other direct contact sequestration methods. PMID:20605108

Vennapusa, Rami Reddy; Fernandez-Lahore, Marcelo

2010-11-01

324

Structure determination of molecular adsorbates with dynamical LEED and HREELS  

Energy Technology Data Exchange (ETDEWEB)

Molecular adsorbate structures can be determined by combined Low-Energy Electron Diffraction (LEED) with High-Resolution Electron Energy Loss Spectroscopy (HREELS). The HREEL vibrational spectroscopy identifies the molecular species, whose bond lengths and angles are obtained by LEED. Appropriate calculational methods are required in LEED to solve complex molecular structures: such methods will be discussed for large molecules, for large unit cells and for disordered adsorbates. Results have been obtained for the following molecular species adsorbed on several low-Miller-index metal surfaces: CO, C/sub 2/H/sub 2/ ..-->.. CCH/sub 3/, C/sub 3/H/sub 4/, ..-->.. CCH/sub 2/CH/sub 3/ and C/sub 6/H/sub 6/. The presently available methods should be capable of solving a multitude of molecular adsorbate structures, including large molecules, coadsorbates and disordered species.

Van Hove, M.A.

1984-08-01

325

Possible uses of inorganic adsorbents in nuclear power engineering  

International Nuclear Information System (INIS)

A survey is presented of the research results of selected inorganic adsorbents available in Czechoslovakia. The research was carried out at UJV Rez with the aim of finding suitable applications of these adsorbents to the decontamination of liquid media and wastes from Czechoslovak nuclear power installations. Several examples are given to show the use of inorganic adsorbents abroad. Of the studied adsorbents, synthetic modernite was chosen which was investigated with regard to the removal of cesium radioisotopes from the coolant of the spent fuel transport and storage tank, further hydrated titanium dioxidde for trapoing Sr, Co and Mn from liquid media containing boric acid and borates, and natural clinoptilolite and mordenite for removing cesium from liquid wastes from special laundries of WWER nuclear power plants. (author)

1985-06-06

326

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

327

Development of ultrafiltration and adsorbents: April-September 1979  

International Nuclear Information System (INIS)

Tests were begun on influent from the radioactive waste disposed plant spiked with other actinides, but problems with the laboratory-scale reverse osmosis (RO) unit led to postponement of these tests. Laboratory-scale RO tests on solution spiked with fission products showed very good rejection (98 to 100%) of 60Co, 137Cs, and 131I. A literature search was made for references to actinide and fission product removal from waste streams by adsorbents. A table lists adsorbents and what elements they remove. A cross reference of adsorbents was compiled in a series of tables so that data from different waste treatment reports can be compared. Laboratory column experiments on Co, Cs, and I gave decontamination factors (DF) for several adsorbers. Engineering tests on Am, Pu, U, and Np are reported at several flow rates and at pH values of 3, 7, and 10. DFs for these actinides are reported

1980-01-01

328

TESTING OF CARBONACEOUS ADSORBENTS FOR REMOVAL OF POLLUTANTS FROM WATER  

Directory of Open Access Journals (Sweden)

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

RAISA NASTAS

2012-03-01

329

Re-generating method and device for tritium water adsorbent  

Energy Technology Data Exchange (ETDEWEB)

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.).

Numata, Shigeo; Hirata, Naruhito.

1990-04-16

330

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

331

Chirped pulse Two Photon Photoemission technique to study adsorbate dynamics  

Energy Technology Data Exchange (ETDEWEB)

Time resolved Two Photon Photoemission (TR 2PPE) is a well-known method in surface physics to study adsorbate dynamics. However, it's temporal resolution is limited by the Heisenberg uncertainty principle. Here we propose a novel method to observe dynamics of adsorbate states using Chirped Pulse Two Photon Photoemission (CP 2PPE). This method utilizes a suitable modified spectral phase of the exciting femtosecond laser pulse, modulated by a Fork prism pair. We apply this technique in the case of Cs/Cu(111), where we observe significant energy shifts of the excited adsorbate state (Cs*) as well as a peak broadening. The obeserved asymmetry in peak position is suggestive of possible adsorbate motion. We further propose to apply the method of CP 2PPE to systems with shorter time constants where time resolved methods are restricted.

Bader, Marianne; Sarkar, Indranil; Steeb, Felix; Ruffing, Andreas; Aeschlimann, Martin [Department of Physics, University of Kaiserslautern, 67663 Kaiserslautern (Germany)

2010-07-01

332

Carbon Dioxide Removal System of the Regenerable Solid Adsorbent Type.  

Science.gov (United States)

The development of a regenerable carbon dioxide removal system is discussed. The system utilizes solid zeolites to adsorb carbon dioxide and silica gel for predrying the gas stream. The system is completely regenerable, operates automatically and continuo...

G. A. Remus P. P. Nuccio R. J. Honegger

1969-01-01

333

Characterization of novel adsorbents for radiostrontium reduction in foods  

International Nuclear Information System (INIS)

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

1999-04-01

334

Spectroelectrochemical studies of metallophthalocyanines adsorbed on electrode surfaces  

Energy Technology Data Exchange (ETDEWEB)

Co(II) and Fe(II)-phthalocyanines adsorbed on platinum and various carbon electrode surfaces have been studied by spectroelectrochemical techniques. The metallophthalocyanine (MPc) films were prepared on substrate electrodes by a drop-dry method after dissolving them in pyridine. While not much change in the spectroscopic properties is observed for MPcs adsorbed at the platinum electrode, both the Soret and Q bands were significantly broadened when adsorbed on the carbon electrodes. Also, the metal-ligand charge-transfer (MLCT) bands are observed from CoPc films adsorbed on carbon substrates even if they are not reduced. These observations lead to the conclusion that the MPc molecules not only undergo oligomerization but also interact strongly with carbon surfaces by perhaps sharing the {pi}-electrons of carbon. MPcs have been used as effective catalysts for oxygen reduction, which is used as a cathode reaction in fuel cells and metal-air batteries.

Mho, S.; Ortiz, B.; Park, S.M. [Univ. of New Mexico, Albuquerque, NM (United States). Dept. of Chemistry; Ingersoll, D.; Doddapaneni, N. [Sandia National Labs., Albuquerque, NM (United States)

1995-05-01

335

In-line hydrocarbon adsorber system for ULEV  

Energy Technology Data Exchange (ETDEWEB)

An in-line hydrocarbon (HC) adsorber system was developed to reduce cold start HC emissions. The system comprises a first catalyst, adsorber unit, and a second catalyst for oxidation of desorbed HC. During cold start, exhaust gas is directed to the hydrocarbon adsorber using a fluidic flow diverter unit without any mechanical moving parts in the exhaust system. After the first catalyst lights off, the diverter is shut off and the major portion of the exhaust gas then flows directly to the second catalyst without heating the adsorber unit. After the second catalyst reaches light-off temperature additional air was added to oxidize the desorbed HC. The system attributes are: NMHC emissions in ULEV range; straight line axial flow; reliable design; and limited back pressure penalty. The system was tested on a 3.8L US vehicle.

Patil, M.D.; Hertl, W.; Williams, J.L.; Nagel, J.N. [Corning, Inc., NY (United States)

1996-09-01

336

Electronic structure of benzene adsorbed on Ni and Cu surfaces  

Energy Technology Data Exchange (ETDEWEB)

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

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

1997-04-01

337

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

338

The Density and Refractive Index of Adsorbing Protein Layers  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The structure of the adsorbing layers of native and denatured proteins (fibrinogen, ?-immunoglobulin, albumin, and lysozyme) was studied on hydrophilic TiO2 and hydrophobic Teflon-AF surfaces using the quartz crystal microbalance with dissipation and optical waveguide lightmode spectroscopy techniques. The density and the refractive index of the adsorbing protein layers could be determined from the complementary information provided by the two in situ instruments. The observed density and re...

Vo?ro?s, Janos

2004-01-01

339

Simulations of the kinetic friction due to adsorbed surface layers  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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 ...

He, Gang; Robbins, Mark O.

2000-01-01

340

Development of solid adsorbent materials for CO?capture  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The application of solid adsorbents for gas separation in pre-combustion carbon capture from gasification processes has gained attention in recent times. This is due to the potential of the technology to reduce the overall energy penalty associated with the capture process. However, this requires the development of solid adsorbent materials with large selectivity, large adsorption capacity, fast adsorption kinetics for CO2 coupled with good mechanical strength and thermal stability. In this ...

2013-01-01

 
 
 
 
341

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

International Nuclear Information System (INIS)

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

1989-01-01

342

???????????? ????????? ??????????? ? ???????? ??????? ?????????????? 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 D. Nedaiborshch

2008-02-01

343

Supramolecular organization of collagen layers adsorbed on polymers  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The aim of this work is to better understand the factors and mechanisms leading to the supramolecular organization of collagen layers adsorbed on polymers. Native collagen adsorption on polystyrene (PS) and plasma-oxidized polystyrene (PSox) substrates revealed that the adsorbed layer consists in two parts: a dense and thin sheet (~ 10 nm) in which fibrils are formed, as revealed by atomic force microscopy, and an overlying thick layer (~ 200 nm) which contains protruding molecules, as reveal...

Gurdak, Elzbieta

2006-01-01

344

Intrinsic Friction of Monolayers Adsorbed on Solid Surfaces  

CERN Multimedia

We overview recent results on intrinsic frictional properties of adsorbed monolayers, composed of mobile hard-core particles undergoing continuous exchanges with a vapor phase. In terms of a dynamical master equation approach we determine the velocity of a biased impure molecule - the tracer particle (TP), constrained to move inside the adsorbed monolayer probing its frictional properties, define the frictional forces exerted by the monolayer on the TP, as well as the particles density distribution in the monolayer.

Bénichou, O; Coninck, J D; Moreau, M; Oshanin, G

2003-01-01

345

Chemical reactivity and structural determination of metal and gaseous adsorbates on Cu{100} using TPD and LEED  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The structures formed by adsorbing thin-film platinum, formic acid and oxygen on Cu{ 100} single crystal are investigated by quantitative low-energy electrondiffraction (LEED) and Temperature Programmed Reaction Spectroscopy (TPRS) Symmetrized Automated Tensor LEED (SATLEED) calculations are used to determine the structure of the formed surface alloys and overlayers. TPRS was used to probe the surface reactivity of the systems studied while surface composition was obtained using Auger Electro...

Younis Ahmed, Hamid M.

2003-01-01

346

Adsorption of noble gas on various adsorbents at cryogenic temperatures  

International Nuclear Information System (INIS)

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

2007-04-22

347

Spermine Sepharose as a clustered-charge anion exchange adsorbent.  

Science.gov (United States)

We previously showed that the affinity and capacity of ion exchange adsorbents of a given total charge density are improved by immobilization of the charges in pre-ordered clusters, rather than individually in random locations. This previous work used pentalysinamide and pentaargininamide as clustered ligands. This approach allows close control of cluster size, but is uneconomically expensive for some research and most practical applications. In this work, we demonstrate that the inexpensive synthetic analog of the natural polyamine spermine (H2N-CH2-CH2-CH2-NH-CH2-CH2-CH2-CH2-NH-CH2-CH2-CH2-NH2) also can serve as the basis of effective clustered adsorbents. The calcium-depleted form of the protein ?-lactalbumin, and RNA from baker's yeast, were adsorbed on a spermine Sepharose adsorbent. This adsorbent exhibited enhanced ?-lactalbumin binding capacity (Qmax>1.6 and 1.3-fold higher than those for Qiagen DEAE and GE DEAE Sepharose adsorbents of much greater charge density) and higher initial binding affinity (Qmax/KD 2.4 and 2.1-fold higher, respectively). The new spermine-based matrix exhibited a higher value of the Z parameter, suggesting an increased number of apparent interaction sites between the protein and the resin, and functioned well in column mode. PMID:24296294

Dhamane, Sagar; Ruiz-Ruiz, Federico; Chen, Wen-hsiang; Kourentzi, Katerina; Benavides, Jorge; Rito-Palomares, Marco; Willson, Richard C

2014-01-10

348

Efforts to Consolidate Chalcogels with Adsorbed Iodine  

Energy Technology Data Exchange (ETDEWEB)

This document discusses ongoing work with non-oxide aerogels, called chalcogels, that are under development at the Pacific Northwest National Laboratory as sorbents for gaseous iodine. Work was conducted in fiscal year 2012 to demonstrate the feasibility of converting Sn2S3 chalcogel without iodine into a glass. This current document summarizes the work conducted in fiscal year 2013 to assess the consolidation potential of non-oxide aerogels with adsorbed iodine. The Sn2S3 and Sb13.5Sn5S20 chalcogels were selected for study. The first step in the process for these experiments was to load them with iodine (I2). The I2 uptake was ~68 mass% for Sn2S3 and ~50 mass% for Sb13.5Sn5S20 chalcogels. X-ray diffraction (XRD) of both sets of sorbents showed that metal-iodide complexes were formed during adsorption, i.e., SnI4 for Sn2S3 and SbI3 for Sb13.5Sn5S20. Additionally, metal-sulfide-iodide complexes were formed, i.e., SnSI for Sn2S3 and SbSI for Sb13.5Sn5S20. No XRD evidence for unreacted iodine was found in any of these samples. Once the chalcogels had reached maximum adsorption, the consolidation potential was assessed. Here, the sorbents were heated for consolidation in vacuum-sealed quartz vessels. The Sb13.5Sn5S20 chalcogel was heated both (1) in a glassy carbon crucible within a fused quartz tube and (2) in a single-containment fused quartz tube. The Sn2S3 chalcogel was only heated in a single-containment fused quartz tube. In both cases with the single-containment fused quartz experiments, the material consolidated nicely. However, in both cases, there were small fractions of metal iodides not incorporated into the final product as well as fused quartz particles within the melt due to the sample attacking the quartz wall during the heat treatment. The Sb13.5Sn5S20 did not appear to attack the glassy carbon crucible so, for future experiments, it would be ideal to apply a coating, such as pyrolytic graphite, to the inner walls of the fused quartz vessel to prevent melt attack.

Riley, Brian J.; Pierce, David A.; Chun, Jaehun

2013-08-28

349

Oxidation and Corrosion of Ceramics and Ceramic Matrix Composites  

Science.gov (United States)

Ceramics and ceramic matrix composites are candidates for numerous applications in high temperature environments with aggressive gases and possible corrosive deposits. There is a growing realization that high temperature oxidation and corrosion issues must be considered. There are many facets to these studies, which have been extensively covered in some recent reviews. The focus of this paper is on current research, over the past two years. In the authors' view, the most important oxidation and corrosion studies have focused on four major areas during this time frame. These are; (I) Oxidation of precursor-based ceramics; (II) Studies of the interphase material in ceramic matrix composites; (III) Water vapor interactions with ceramics, particularly in combustion environments; and (IV) Development of refractory oxide coatings for silicon-based ceramics. In this paper, we shall explore the most current work in each of these areas.

Jacobson, Nathan S.; Opila, Elizabeth J.; Lee, Kang N.

2000-01-01

350

Gold recovery from low concentrations using nanoporous silica adsorbent  

Science.gov (United States)

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

Aledresse, Adil

351

Uranium Adsorption with Composite Titanium-Iron Hydrous Oxide Microspheres.  

Science.gov (United States)

Microsphere type of composite hydrous titanium-iron oxides prepared by internal gelation method from homogeneous solutions were studied with a view to developing a better adsorbent for uranium recovery from seawater. Both uranium adsorption capacity and e...

T. J. Wen T. S. C. C. Huang

1983-01-01

352

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

2013-01-01

353

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.

Forushani Abbas Rahimi

2013-01-01

354

Utility of adsorbents in the purification of drinking water: a review of characterization, efficiency and safety evaluation of various adsorbents.  

Science.gov (United States)

Clean drinking water is one of the implicit requisites fora healthy human population. However the growing industrialization and extensive use of chemicals for various concerns, has increased the burden of unwanted pollutants in the drinking water of developing countries like India. The entry of potentially hazardous substances into the biota has been magnifying day by day. In the absence of a possible stoppage of these, otherwise, useful chemicals, the only way to maintain safer water bodies is to develop efficient purifying technologies. One such immensely beneficial procedure that has been in use is that of purification of water using 'adsorbents'. Indigenous minerals and natural plants products have potential for removing many pollutants viz. fluoride, arsenic, nitrate, heavy metals, pesticides as well as trihalomethanes. Adsorbents which are derived from carbon, alumina, zeolite, clay minerals, iron ores, industrial by products, and natural products viz. parts of the plants, herbs and algal biomass offer promising potential of removal. In the recent years attention has been paid to develop process involving screening/pretreatment/activation/impregnation using alkalies, acids, alum, lime, manganese dioxide, ferric chloride and other chemicals which are found to enhance their adsorbing efficiency. Chemical characterization of these adsorbents recapitulates the mechanism of the process. It is imperative to observe that capacities of the adsorbents may vary depending on the characteristics, chemical modifications and concentration of the individual adsorbent. Removal kinetics is found to be based on the experimental conditions viz. pH, concentration of the adsorbate, quantity of the adsorbent and temperature. It is suggested that isotherm model is suitable tool to assess the adsorption capacities in batch and column modes. Safety evaluation and risk assessment of the process/products may be useful to provide guidelines for its sustainable disposal. PMID:20120453

Dubey, Shashi Prabha; Gopal, Krishna; Bersillon, J L

2009-05-01

355

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

356

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

International Nuclear Information System (INIS)

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

2012-07-01

357

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

International Nuclear Information System (INIS)

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

2013-07-01

358

Improvement of corrosion and biological properties of microarc oxidized coatings on Mg-Zn-Zr alloy by optimizing negative power density parameters.  

Science.gov (United States)

Corrosion and biological properties of microarc oxidized calcium phosphate (CaP) coatings on Mg-Zn-Zr alloy were improved by optimizing negative power density parameters. Scanning electron microscope (SEM) and X-ray diffractometer (XRD) were employed to characterize the coating morphology and phase composition. The in vitro cytotoxicity and systemic toxicity tests were carried out to evaluate the coating biocompatibility. The degradability and bioactivity of the coatings were determined by in vitro simulated body fluid (SBF) immersion test. The coating microstructure, thickness and growth rate can be influenced by negative power density through changing direction of ions movements, rate of ions exchanges and affecting formation of plasma. The CaP coatings reduced the substrate degradation rate. Calcium phosphates, such as hydroxyapatite (Ca10(PO4)6(OH)2, HA) and calcium pyrophosphate (Ca2P2O7, CPP), etc., were induced after 30 days SBF immersion, indicating that the coatings have bioactivity. The CaP coatings have no toxicity to cell and living mice, indicating that the coatings are safe to serve as implants. PMID:24140795

Pan, Y K; Chen, C Z; Wang, D G; Zhao, T G

2014-01-01

359

Evaluation of Adsorption Properties for Cs and Sr Selective Adsorbents-13171  

International Nuclear Information System (INIS)

The development of effective treatment and disposal methods is very urgent and important subject. Tohoku University and UNION SHOWA have developed various selective adsorbents (zeolites, zeolite sheets and composites loaded with insoluble ferrocyanides) for the effective decontamination of radioactive Cs+ and Sr2+ As for Cs+ adsorption, CST, chabazite and insoluble ferrocyanides composites had relatively large distribution coefficients (Kd) above 103 cm3/g and excellent adsorption kinetics in seawater. Even after high temperature calcination at 1,100 deg. C, cesium was still immobilized in the calcined products of Cs+-zeolites, suggesting high immobilization ability of zeolites for Cs+. As for Sr2+ adsorption, A and X zeolites had relatively large Kd values around 102 cm3/g, and zeolite sheet (A zeolite) exhibited excellent adsorption kinetics in seawater. Considering the decontamination of radioactive Sr2+ in groundwater, the effects of Ca2+ and Mg2+ ions on the Kd value of Sr2+ were further examined by batch method. The Kd value of Sr2+ was almost independent of Mg2+ concentration up to 2,500 ppm, while gradually lowered in the presence of Ca2+ above 200 ppm, due to the differences in the ionic radius of hydrated ion. The Cs+ and Sr2+ adsorption ability for KNiFC-A (composite of A zeolite loaded with insoluble ferrocyanides) was examined by batch method. Here the matrix of composite (A zeolite) and loaded ferrocyanides (KNiFC) have high selectivity towards Sr2+ and Cs+, respectively. The Kd values of Sr2+ and Cs+ in seawater were estimated to be above 102 and 103 cm3/g, respectively, indicating the effectiveness for the decontamination of both Sr2+ and Cs+. The basic data on the Cs+ and Sr2+ adsorption properties for selective adsorbents are effective for the practical decontamination processes of these metal ions in seawater and groundwater. (authors)

2013-02-24

360

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

CERN Document Server

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

 
 
 
 
361

Use of activated natural adsorbent in white oil production  

Energy Technology Data Exchange (ETDEWEB)

This article reports on the preparation of an activated natural adsorbent (AGTs-2), based on bentonite from the Askansk deposit, for use in white oil production. Sulfuric acid was used for the bentonite activation. Data is presented on the decolorizing properties and filterability of the activated natural adsorbent in comparison with natural Zikeevo clay. It is determined that the production of a technical white oil with a TsNT color of 1 requires half the amount of AGTs-2 activated adsorbent in comparison with the Zikeevo clay. Both adsorbents have good neutralizing properties and all of the finished oils have a zero acid number. In the production of viscous white oils, the efficiency of contact finishing with the AGTs-2 is higher. The comparative data on the filtration rates of the oil/clay slurry for the different oil samples shows that when AGTs-2 is used, the filtration rate is 3-5 times that with the Zikeevo clay. It is concluded that the AGTs-2 activated natural adsorbent is preferable for white oil production. Includes 2 tables.

Potanina, V.A.; Dremova, T.I.; Kustova, G.L.; Mokhova, L.A.

1984-03-01

362

Adsorption of rare earths with crown ether adsorbents  

International Nuclear Information System (INIS)

Crown ether - phosphotungstic acid (PW) and crown ether -phosphomolybdic acid (PMo) precipitates, and also the granular entrapped crown ether - PMo (or PW) in polyacrylamide, were prepared and applied as adsorbents for rare earth metal ions. Adsorbents containing 15-crown-5, such as 15-crown-5 - PMo, were better adsorbents than the other crown ether precipitates. The adsorption capacity of 15-crown-5 - PMo for Eu3+ was determined and corresponded to about 0.166 mmol of Eu3+ per gram of the absorbent. The effects of pH and metal ion concentration on adsorption were also investigated. Crown ether - PMo (or PW) precipitates underwent hydrolysis at pH >= 1, but the granular entrapped crown ether - PMo (or PW) - polyacrylamide adsorbents were not hydrolysed at pH >= 1. The adsorption of individual rare earth ions with 15-crown-5 - PMo - polyacrylamide showed that Tb3+, Nd3+, Eu3+ and Gd3+ were readily adsorbed, but adsorption was difficult for Ce4+, Sm3+ and Dy3+. (author)

1985-01-01

363

High capacity cryogel-type adsorbents for protein purification.  

Science.gov (United States)

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

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

2014-08-15

364

Aminosilane-grafted polymer/silica hollow fiber adsorbents for CO? capture from flue gas.  

Science.gov (United States)

Amine/silica/polymer composite hollow fiber adsorbents are produced using a novel reactive post-spinning infusion technique, and the obtained fibers are shown to capture CO2 from simulated flue gas. The post-spinning infusion technique allows for functionalization of polymer/silica hollow fibers with different types of amines during the solvent exchange step after fiber spinning. The post-spinning infusion of 3-aminopropyltrimethoxysilane (APS) into mesoporous silica/cellulose acetate hollow fibers is demonstrated here, and the materials are compared with hollow fibers infused with poly(ethyleneimine) (PEI). This approach results in silica/polymer composite fibers with good amine distribution and accessibility, as well as adequate porosity retained within the fibers to facilitate rapid mass transfer and adsorption kinetics. The CO2 adsorption capacities for the APS-infused hollow fibers are shown to be comparable to those of amine powders with similar amine loadings. In contrast, fibers that are spun with presynthesized, amine-loaded mesoporous silica powders show negligible CO2 uptake and low amine loadings because of loss of amines from the silica materials during the fiber spinning process. Aminosilica powders are shown to be more hydrophilic than the corresponding amine containing composite hollow fibers, the bare polymer as well as silica support. Both the PEI-infused and APS-infused fibers demonstrate reduced CO2 adsorption upon elevating the temperature from 35 to 80 °C, in accordance with thermodynamics, whereas PEI-infused powders show increased CO2 uptake over that temperature range because of competing diffusional and thermodynamic effects. The CO2 adsorption kinetics as probed via TGA show that the APS-infused hollow fiber adsorbents have more rapid uptake kinetics than their aminosilica powder analogues. The adsorption performance of the functionalized hollow fibers is also assessed in CO2 breakthrough experiments. The breakthrough results show a sharp CO2 front for APS-grafted fibers, indicating fast kinetics with comparable pseudo-equilibrium capacities to the CO2 equilibrium capacities measured via thermogravimetric analysis (TGA). The results indicate the post-spinning infusion method provides a new platform for synthesizing composite polymer/silica/amine fibers that may facilitate the ultimate scale-up of practical fiber adsorbents for flue gas CO2 capture applications. PMID:23540568

Rezaei, Fateme; Lively, Ryan P; Labreche, Ying; Chen, Grace; Fan, Yanfang; Koros, William J; Jones, Christopher W

2013-05-01

365

The effect of the addition of colloidal iridium oxide into sol-gel obtained titanium and ruthenium oxide coatings on titanium on their electrochemical properties.  

Science.gov (United States)

Electrochemical properties of sol-gel processed Ti(0.6)Ir(0.4)O(2) and Ti(0.6)Ru(0.3)Ir(0.1)O(2) coatings on titanium substrate were investigated using cyclic voltammetry, polarization measurements and electrochemical impedance spectroscopy and compared to the properties of Ti(0.6)Ru(0.4)O(2) coating. The role of iridium oxide in the improvement of the electrocatalytic, capacitive and stability properties of titanium anodes activated by a RuO(2)-TiO(2) coating is discussed. The oxide sols were prepared by forced hydrolysis of the metal chlorides. The characterization by dynamic light scattering and X-ray diffraction showed that polydisperse oxide sols were obtained with the particles tending to form agglomerates. The presence of IrO(2) causes a suppression of the X-ray diffraction peaks of TiO(2) and RuO(2) in the sol-gel prepared Ti(0.6)Ir(0.4)O(2) and Ti(0.6)Ru(0.3)Ir(0.1)O(2) coatings. The IrO(2)-containing coatings had an enhanced charge storage ability and activity for the oxygen evolution reaction (OER) in comparison to Ti(0.6)Ru(0.4)O(2) coating. The voltammogram of the Ti(0.6)Ir(0.4)O(2)/Ti electrode showed well-resolved peaks related to Ir redox transitions, which are responsible for the enhanced charge storage ability of IrO(2)-containing coatings. Redox transitions of Ir were also registered in the high-frequency domain of the ac impedance spectra of the coatings as a semicircle with characteristics insensitive to the electrolyte composition and to the electrode potential prior to OER. However, the semicircle characteristics were different for the two IrO(2)-containing coatings, as well as at potentials outside the OER in comparison to those at which the OER occurs. PMID:20544088

Pani?, Vladimir V; Dekanski, Aleksandar B; Mitri?, Miodrag; Milonji?, Slobodan K; Miskovi?-Stankovi?, Vesna B; Nikoli?, Branislav Z

2010-07-21

366

Viability of banana pith use as adsorbent for uranium ions  

International Nuclear Information System (INIS)

In this work banana pith was investigated as adsorbent for uranium ions from nitric solutions. The use of this type of biomaterial reduces environmental impact of two forms, the banana pith that is considered a pollutant, is removed of place where was generated or deposited and contaminated effluents can be treated by this residual biomass. One another important aspect is the reutilization of both biomass and metals adsorbed that can be recovered by desorption processes. It is a natural material of low cost and easy application. Influence of adsorbent size and adsorption kinetic were studied. The studies of adsorption followed both Langmuir and Freundlich models. In concentration range of 0.1 - 4.0 g/L, the adsorption process was described better by Freundlich equation. (author)

2005-09-02

367

Radioactive diffusion gaseous probe technique for study adsorbent structure inhomogeneity  

International Nuclear Information System (INIS)

One of the versions of the method of diffusion gaseous probe - method of longitudinal shear in combination with autoradiography (ARG) - was used for characterising sorbents and catalysts, which are considered to be promising for reprocessing of sulfur-containing natural gases. Hydrogen sulfide, labelled with 35S was used as diffusion radioactive probe. Zeolite granules of 4A type and granulated adsorbents on the basis of CR and AM aluminium oxides, which are industrial catalysts of Clauss reaction developed at SNEA company, were used as objects under investigation. It is shown that technique for fabrication of 4A zeolite granules leads to asymmetrical pore distribution over the granule diameter. Technique for AM granule fabrication leads to occuRrence of local inhomogeneities of the structure in the form of narrow coaxial rings with decreased or increased local adsorption ability. Granules of adsorbent of CR type are characterized by rather homogeneous structure. It is recommended to use the mentioned method for industrial adsorbent diagnosis

1990-01-01

368

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

369

Ultraviolet and electron radiation induced fragmentation of adsorbed ferrocene  

International Nuclear Information System (INIS)

From thermal desorption spectroscopy we find that ferrocene, Fe(C5H5)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 1996 American Institute of Physics

1996-06-01

370

Carbonaceous adsorbents for the protection of the environment  

International Nuclear Information System (INIS)

Problems of utilization, production and characterization of brown coal carbonaceous adsorbents are included in the contributions. At first, the types of industrial important adsorbents - activated carbon, active coke and carbonaceous molecular sieves - their fields of application and the fundamental principles of their production are described. Four contributions deal with the utilization of active coke for environmental protection. New results of laboratory scale and of technical plants investigations for the waste gas cleaning and for the waste water treatment, respectively are described. Moreover, four contributions deal with the production of active coke and activated carbon under laboratory scale conditions and in an industrial plant, respectively. Problems of the characterization of carbonaceous adsorbents are included in two articles. (orig.)

1993-01-01

371

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.

2013-01-01

372

A new adsorbent for boron removal from aqueous solutions.  

Science.gov (United States)

A new adsorbent based on natural clinoptilolite and amorphous zirconium dioxide (ZrO2) was prepared for the uptake of boron from fresh water. The sorption behaviour of this adsorbent for boron was investigated using a batch system and found to obey Langmuir, Freundlich and Dubinin-Radushkevich (D-R) isotherm models. The ZrO2 loading level, pH, temperature, contact time, initial boron concentration and adsorbent dose, on the removal of boron were studied. It was found that the removal of boron increased while the adsorbent dose increased and the temperature decreased at an optimum pH (pH = 8) and a contact time of 30 min. At optimum conditions, the maximum boron percentage removal was 75%. According to the D-R model, the maximum capacity was estimated to be > 3 mg B/g of the adsorbent. The adsorption energy value (calculated as 9.13 kJ/mol) indicated that the adsorption of boron on clinoptilolite modified with ZrO2 was physical in nature. The parameters of the adsorption models and the pH investigations pointed to the possibility of a chemisorption process. The thermodynamic parameters (standard entropy deltaS degrees, enthalpy deltaH degrees , and free energy deltaG degrees changes) of boron adsorption were also calculated. The negative value of deltaS degrees indicated a decreased randomness at the solid-solution interface during the boron adsorption. Negative values of deltaH degrees showed the exothermic nature of the process. The negative values of deltaG degrees implied that the adsorption of boron on clinoptilolite modified with amorphous ZrO2 at 25 degrees C was spontaneous. It was considered that boron dissolved in water had been adsorbed both physically and chemically on clinoptilolite modified with 30% ZrO2. PMID:24191469

Kluczka, Joanna; Korolewicz, Teofil; Zo?otajkin, Maria; Simka, Wojciech; Raczek, Malwina

2013-01-01

373

Removal of fluoride from groundwater by adsorption onto La(III)- Al(III) loaded scoria adsorbent  

Science.gov (United States)

The La3+-Al3+ loaded scoria (La-Al-Scoria) was prepared as adsorbent for the fluoride removal from groundwater. The connecting time experiment indicated that the fluoride adsorption process reached equilibrium within 5 hours. The kinetics of fluoride ion adsorption onto La-Al-Scoria was followed the pseudo-second order with correlation coefficient value (R2) of 0.997. The isotherm data was well fitted to both of the Freundlich and Langmuir isotherm models, the R2 of Freundlich and Langmuir were 0.98 and 0.97, respectively. Subsequently, the adsorbent was characterized by scanning electron microscope (SEM), Energy dispersive analysis of X-ray (EDX), X-ray diffraction analysis (XRD) and X-ray Photoelectron Spectroscopy (XPS) measurements. SEM visual expressed that the dense canal surface structure of natural scoria appeared a large amount of rod-like composite after modification. The XRD and XPS instrumental studies revealed that the La3+ and Al3+ were loaded on the surface of modified scoria and the fluoride ion was adsorbed on the La-Al-Scoria. The large amount of La-Al-O composite oxide existed onto the surface of La-Al-Scoria was the immanent cause for the excellent adsorption capacity of fluoride ion.

Zhang, Shengyu; Lu, Ying; Lin, Xueyu; Su, Xiaosi; Zhang, Yuling

2014-06-01

374

AQUATIC PHOTOLYSIS OF OXY-ORGANIC COMPOUNDS ADSORBED ON GOETHITE.  

Science.gov (United States)

Organic materials that will not absorb light at wavelengths longer than 295 nanometers (the solar wavelength cutoff) may nevertheless, undergo electron transfer reactions initiated by light. These reactions occur when the organic materials are adsorbed as ligand complexes to the surface of iron oxy-hydroxide (goethite). The adsorbed materials can be either inner or outer coordination sphere complexes. Goethite was chosen as the iron oxyhydroxide surface because it has the highest thermodynamic stability of any of the oxyhydroxides in water and it can be synthesized easily, with high purity.

Goldberg, Marvin, C.

1985-01-01

375

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

Energy Technology Data Exchange (ETDEWEB)

Atoms and molecules adsorbed on metals affect each other even over considerable distances. In a tour-de-force of density-functional methods, the authors establish the nature and strength of such indirect interactions, and explain for what adsorbate systems they can critically affect important materials properties. These perceptions are verified in kinetic Monte Carlo simulations of epitaxial growth, and help rationalize a cascade of recent experimental reports on anomalously low diffusion prefactors. The authors focus their study on two metal systems: Al/Al(111) and Cu/Cu(111).

BOGICEVIC,ALEXANDER; OVESSON,S.; HYLDGAARD,P.; LUNDQVIST,B.I.; JENNISON,DWIGHT R.

2000-02-14

376

Phase Diagram of Adsorbate-Induced Row-Type-Alignments  

CERN Document Server

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

377

Simulations of the Static Friction Due to Adsorbed Molecules  

CERN Multimedia

The static friction between crystalline surfaces separated by a molecularly thin layer of adsorbed molecules is calculated using molecular dynamics simulations. These molecules naturally lead to a finite static friction that is consistent with macroscopic friction laws. Crystalline alignment, sliding direction, and the number of adsorbed molecules are not controlled in most experiments and are shown to have little effect on the friction. Temperature, molecular geometry and interaction potentials can have larger effects on friction. The observed trends in friction can be understood in terms of a simple hard sphere model.

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

2001-01-01

378

Cryogenic adsorption of hydrogen isotopes on carbonaceous adsorbents. Pt.2  

International Nuclear Information System (INIS)

Adsorption isotherms of H2 and D2 on activated carbon (AC), carbon molecular sieve (601) and carbon nano-fibers (CNF) are investigated at the liquid nitrogen temperature. Both the one-site and two-site Langmuir models are used for isotherm calculation. Results indicate that all isotherms of H2 and D2 on AC, 601 and CNF can be expressed well with the two-site Langmuir model. Accordingly, it can be inferred that, while adsorbed on carbonaceous adsorbents at the liquid nitrogen temperature, hydrogen isotope molecules should occupy the multiple types of active sites to form a localized monolayer

2003-03-01

379

Sers effect of hexamethylenetetramine adsorbed on a silver electrode  

Science.gov (United States)

Surface enhanced Raman scattering (SERS) of hexamethylenetetramine (HMTA) adsorbed on a silver electrode has been obtained and the dependence on the pH, applied potential, electrolyte anion and exciting radiation are discussed. Only certain totally symmetric modes presented enhancement. The pH variation of the solution from 9.0 to 5.0 produced modifications in the SERS spectra which could be explained by the presence of HMTA species at high pH values, while the species HMTAH + is adsorbed via both ion pair information and one of the nonprotonated nitrogens of the molecule at lower pH.

Bertolino, J. R.; Temperini, M. L. A.; Sala, O.

1988-08-01

380

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)

2007-09-01

 
 
 
 
381

Neointimal coverage and vasodilator response to titanium-nitride-oxide-coated bioactive stents and everolimus-eluting stents in patients with acute coronary syndrome: insights from the BASE-ACS trial.  

Science.gov (United States)

Incomplete stent endothelialization is associated with late and very late stent thrombosis. In a post hoc analysis of the BASE-ACS trial, we sought to assess neointimal coverage and coronary flow reserve (CFR) 9 months after implantation of titanium-nitride-oxide-coated bioactive stents (BAS) versus everolimus-eluting stents (EES) in patients with acute coronary syndrome (ACS). In the BASE-ACS trial, 827 patients with ACS were randomized to receive either BAS or EES. In the current study, we examined neointimal growth and strut coverage by optical coherence tomography and CFR by trans-thoracic echocardiography in 28 consecutive non-diabetic patients with the culprit lesion in the left anterior descending coronary artery. The primary endpoints were binary stent strut coverage and CFR at 9-month follow-up. A total of 13 patients were included in the BAS group (2,033 struts); 15 in the EES group (2,898 struts). Binary stent strut coverage was higher and malapposed struts lower with BAS versus EES (99.4 vs 89.2, and 0.2 vs 4.6%, respectively, p < 0.001 for both). Neointimal hyperplasia thickness was greater with BAS versus EES (274.2 vs 100.1 ?m, respectively, p < 0.001). CFR was lower with EES versus BAS (2.2 ± 0.8 vs. 3.0 ± 0.5, respectively, p = 0.001). Abnormal CFR (<2.5) were detected in 10 patients in the EES group versus one in the BAS group (p = 0.002). The current study demonstrated that in patients with ACS, BAS resulted in improved neointimal stent strut coverage and better coronary vasodilator function as compared with EES at 9-month follow-up. PMID:23996244

Karjalainen, Pasi; Kiviniemi, Tuomas O; Lehtinen, Tuomas; Nammas, Wail; Ylitalo, Antti; Saraste, Antti; Mikkelsson, Jussi; Pietila, Mikko; Biancari, Fausto; Airaksinen, Juhani K E

2013-12-01

382

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

383

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

384

Adsorption removal of cesium from drinking waters: a mini review on use of biosorbents and other adsorbents.  

Science.gov (United States)

Radiocesium (Cs) removal from waters becomes an emerging issue after the Fukushima Daiichi Nuclear Power Plant Disaster, during which a total of approximately 3.3×10(16) Bq Cs was released to contaminate the environment. This mini-review provided a summary on literature works to develop efficient adsorbent for removing Cs from waters. Adsorbent made of raw and modified minerals, composites particles, and biosorbents that are highly specific to Cs in the presence of other alkali and alkali earth metals were summarized. Development of Prussian blue (PB) nanoparticles on Cs removal and its potential use in drinking waterworks was discussed. This review is a unique report for adsorption removal of Cs from contaminated waters. PMID:24484852

Liu, Xiang; Chen, Guan-Ru; Lee, Duu-Jong; Kawamoto, Tohru; Tanaka, Hisashi; Chen, Man-Li; Luo, Yu-Kuo

2014-05-01

385

Phenol removal from wastewater by adsorption on zeolitic composite.  

Science.gov (United States)

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

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

2013-09-01

386

Utilization of Roselle charcoal as nitrate-nitrogen adsorbent  

Directory of Open Access Journals (Sweden)

Full Text Available Recently, the attempts have been made by utilizing natural material as an adsorbent for wastewater treatment due to its low cost, low energy requirement and the fewer chemicals used. In this study, Roselle (Hibiscus sabdariffa L. var. altissima was prepared to use as a charcoal adsorbent in the treatment process. The nitrate-nitrogen adsorption capacities of Roselle charcoal with 2 different particle sizes, A (4.75- .30 mm and B (2.00-4.75 mm were measured and compared with an activated carbon (AC. The equilibrium data fitted well with the Freundlich Isotherm. The K values related to the capacity of adsorbent for nitratenitrogen of such charcoal studied were in the following orders: AC > B > A expressed as 0.0321, 0.0147 and 0.0071 respectively. In addition, activated carbon required less contact time to reach equilibrium than both of Roselle charcoal A and B. Although removal efficiency of activated carbon was higher than that of Roselle charcoal, Roselle charcoal is an interesting alternative adsorbent due to the lower cost of its production.

Yimrattanabovorn, J.

2006-11-01

387

Removal of emerging contaminants of concern by alternative adsorbents.  

Science.gov (United States)

The effective removal of emerging contaminants of concern (ECCs) such as endocrine-disrupting chemicals, pharmaceutically active compounds, personal care products, and flame retardants is a desirable water treatment goal. In this study, one activated carbon, one carbonaceous resin, and two high-silica zeolites were studied to evaluate their effectiveness for the removal of an ECC mixture from lake water. Adsorption isotherm experiments were performed with a mixture of 28 ECCs at environmentally relevant concentrations ( approximately 200-900 ng/L). Among the tested adsorbents, activated carbon was the most effective, and activated carbon doses typically used for taste and odor control in drinking water (activated carbon because this adsorbent had a smaller volume of pores in the size range required for the adsorption of many ECCs ( approximately 6-9A). For the removal of ECC mixture constituents, zeolites were less effective than the carbonaceous adsorbents. Because zeolites contain pores of uniform size and shape, a few of the tested ECCs with matching pore size/shape requirements were well removed, but the adsorptive removal of others was negligible, even at zeolite doses of 100 mg/L. The results of this study demonstrate that effective adsorbents for the removal of a broad spectrum of ECCs from water should exhibit heterogeneity in pore size and shape and a large pore volume in the 6-9A size range. PMID:19577267

Rossner, Alfred; Snyder, Shane A; Knappe, Detlef R U

2009-08-01

388

An electronics circuit for a pulsed adsorbed dose calorimeter  

International Nuclear Information System (INIS)

Details of an electronics circuit to produce a pulsed rather than conventional dc excitation mechanism are presented for an adsorbed dose calorimeter. The use of pulsing is to increase the bridge output signal while containing troublesome thermistor self-heating to acceptable limits. (orig.)

1989-08-01

389

An electronics circuit for a pulsed adsorbed dose calorimeter  

Energy Technology Data Exchange (ETDEWEB)

Details of an electronics circuit to produce a pulsed rather than conventional dc excitation mechanism are presented for an adsorbed dose calorimeter. The use of pulsing is to increase the bridge output signal while containing troublesome thermistor self-heating to acceptable limits. (orig.).

Kubo, Hideo; Kageyama, Yoshiyuki; Perec, A. (Rochester Univ., NY (USA). Dept. of Radiation Oncology)

1989-08-01

390

EVALUATING VARIOUS ADSORBENTS AND MEMBRANES FOR REMOVING RADIUM FROM GROUNDWATER  

Science.gov (United States)

Field studies were conducted in Lemont, Il, to evaluate specific adsorbents and reverse osmosis (RO) membranes for removing radium from groundwater. adium selective complexer and barium-sulfate-loaded alumina appeared to have the best potential for low-cost adsorption of radium f...

391

Process for preparing a titanium suspension carrying adsorbed tritium  

International Nuclear Information System (INIS)

Tritium is usually available in the form of a gas adsorbed onto a metallic titanium plate, which is inconvenient so far as it is used as a discharge initiator. Here is provided a process for converting a titanium plate carrying adsorbed tritium into a suspension which is more conveniently usable as a discharge initiator for discharge tubes. Metallic titanium is deposited on Cu-Be alloy, onto which tritium is adsorbed. The plate is ground in a organic solvent (acetic esters, acetone, Ethylcellosolve, etc). with a slurry of finely powdered metallic titanium having a size of 0.1 micron or less. The resulting metallic powder is diluted with the organic solvent, to which a binder is added. In one example, a titanium plate carrying 5 curies of adsorbed tritium was ground with 5 g of a slurry of powdered titanium. The resulting powder was diluted with 5 liters of butyl acetate, into which was dissolved 5 g of collodion cotton as a binder. The resulting suspension contained 1 millicurie of tritium per cc. The inner wall of a discharge tube was coated with 0.005 cc of the suspension and dried. After 24 hours in the dark, the voltage of initial discharge was 145 volts which was comparable to the value in ambient illuminence. Without the coating, the voltage of initial discharge was 200 to 270 volts. (Kaichi, S.)

1971-01-01

392

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

393

Fast and efficient protein purification using membrane adsorber systems.  

Science.gov (United States)

The purification of proteins from complex cell culture samples is an essential step in proteomic research. Traditional chromatographic methods often require several steps resulting in time consuming and costly procedures. In contrast, protein purification via membrane adsorbers offers the advantage of fast and gentle but still effective isolation. In this work, we present a new method for purification of proteins from crude cell extracts via membrane adsorber based devices. This isolation procedure utilises the membranes favourable pore structure allowing high flow rates without causing high back pressure. Therefore, shear stress to fragile structures is avoided. In addition, mass transfer takes place through convection rather than diffusion, thus allowing very rapid separation processes. Based on this membrane adsorber technology the separation of two model proteins, human serum albumin (HSA) and immungluboline G (IgG) is shown. The isolation of human growth hormone (hGH) from chinese hamster ovary (CHO) cell culture supernatant was performed using a cation exchange membrane. The isolation of the enzyme penicillin acylase from the crude Escherichia coli supernatant was achieved using an anion exchange spin column within one step at a considerable purity. In summary, the membrane adsorber devices have proven to be suitable tools for the purification of proteins from different complex cell culture samples. PMID:16159680

Suck, Kirstin; Walter, Johanna; Menzel, Frauke; Tappe, Alexander; Kasper, Cornelia; Naumann, Claudia; Zeidler, Robert; Scheper, Thomas

2006-02-10

394

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

395

Activity of alkaline phosphatase adsorbed and grafted on "polydopamine" films.  

Science.gov (United States)

The oxidation of dopamine in slightly basic solutions and in the presence of oxygen as an oxidant allows for the deposition of dopamine-eumelanin ("polydopamine") films on almost all kinds of materials allowing for an easy secondary functionalization. Molecules carrying nucleophilic groups like thiols and amines can be easily grafted on those films. Herein we show that alkaline phosphatase (ALP), as a model enzyme, adsorbs to "polydopamine" films and part of the adsorbed enzyme is rapidly desorbed in contact with Tris buffer. However a significant part of the enzyme remains irreversibly adsorbed and keeps some enzymatic activity for at least 2weeks whereas ALP adsorbed on quartz slides is rapidly and quantitatively deactivated. In addition we estimated the Michaelis constant Km of the enzyme irreversibly bound to the "polydopamine" film. The Michaelis constant, and hence the affinity constant between paranitrophenol phosphate and ALP are almost identical between the enzyme bound on the film and the free enzyme in solution. Complementarily, it was found that "polydopamine" films display some phosphatase like catalytic activity. PMID:24935183

Ball, Vincent

2014-09-01

396

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

2012-08-01

397

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

398