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Sample records for oxide-coated composite adsorbent

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

    Energy Technology Data Exchange (ETDEWEB)

    Fan, Huan Jung; Anderson, P.R.

    1995-12-31

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

  2. Simple and Efficient Synthesis of Iron Oxide-Coated Silica Gel Adsorbents for Arsenic Removal: Adsorption Isotherms and Kinetic Study

    International Nuclear Information System (INIS)

    Iron oxide (ferrihydrite, hematite, and magnetite) coated silica gels were prepared using a low-cost, easily-scalable and straightforward method as the adsorbent material for arsenic removal application. Adsorption of the anionic form of arsenic oxyacids, arsenite (AsO2-) and arsenate (AsO4-3), onto hematite coated silica gel was fitted against non-linear 3-parameter-model Sips isotherm and 2-parameter-model Langmuir and Freundlich isotherm. Adsorption kinetics of arsenic could be well described by pseudo-second-order kinetic model and value of adsorption energy derived from non-linear Dubinin-Radushkevich isotherm suggests chemical adsorption. Although arsenic adsorption process was not affected by the presence of sulfate, chloride, and nitrate anions, as expected, bicarbonate and silicate gave moderate negative effects while the presence of phosphate anions significantly inhibited adsorption process of both arsenite and arsenate. When the actual efficiency to remove arsenic was tested against 1 L of artificial arsenic-contaminated groundwater (0.6 mg/L) in the presence competing anions, the reasonable amount (20 g) of hematite coated silica gel could reduce arsenic concentration to below the WHO permissible safety limit of drinking water of 10 ?g/L without adjusting pH and temperature, which would be highly advantageous for practical field application

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

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

    2009-05-01

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

  4. Reduced graphene oxide-coated hydroxyapatite composites stimulate spontaneous osteogenic differentiation of human mesenchymal stem cells.

    Science.gov (United States)

    Lee, Jong Ho; Shin, Yong Cheol; Jin, Oh Seong; Kang, Seok Hee; Hwang, Yu-Shik; Park, Jong-Chul; Hong, Suck Won; Han, Dong-Wook

    2015-07-21

    Human mesenchymal stem cells (hMSCs) have great potential as cell sources for bone tissue engineering and regeneration, but the control and induction of their specific differentiation into bone cells remain challenging. Graphene-based nanomaterials are considered attractive candidates for biomedical applications such as scaffolds in tissue engineering, substrates for SC differentiation and components of implantable devices, due to their biocompatible and bioactive properties. Despite the potential biomedical applications of graphene and its derivatives, only limited information is available regarding their osteogenic activity. This study concentrates upon the effects of reduced graphene oxide (rGO)-coated hydroxyapatite (HAp) composites on osteogenic differentiation of hMSCs. The average particle sizes of HAp and rGO were 1270 ± 476 nm and 438 ± 180 nm, respectively. When coated on HAp particulates, rGO synergistically enhanced spontaneous osteogenic differentiation of hMSCs, without hampering their proliferation. This result was confirmed by determining alkaline phosphatase activity and mineralization of calcium and phosphate as early and late stage markers of osteogenic differentiation. It is suggested that rGO-coated HAp composites can be effectively utilized as dental and orthopedic bone fillers since these graphene-based particulate materials have potent effects on stimulating the spontaneous differentiation of MSCs and show superior bioactivity and osteoinductive potential. PMID:26098486

  5. Arsenic Removal from Water Using Various Adsorbents: Magnetic Ion Exchange Resins, Hydrous Ion Oxide Particles, Granular Ferric Hydroxide, Activated Alumina, Sulfur Modified Iron, and Iron Oxide-Coated Microsand

    KAUST Repository

    Sinha, Shahnawaz

    2011-09-30

    The equilibrium and kinetic adsorption of arsenic on six different adsorbents were investigated with one synthetic and four natural types (two surface and two ground) of water. The adsorbents tested included magnetic ion exchange resins (MIEX), hydrous ion oxide particles (HIOPs), granular ferric hydroxide (GFH), activated alumina (AA), sulfur modified iron (SMI), and iron oxide-coated mic - rosand (IOC-M), which have different physicochemical properties (shape, charge, surface area, size, and metal content). The results showed that adsorption equilibriums were achieved within a contact period of 20 min. The optimal doses of adsorbents determined for a given equilibrium concentration of C eq = 10 ?g/L were 500 mg/L for AA and GFH, 520–1,300 mg/L for MIEX, 1,200 mg/L for HIOPs, 2,500 mg/L for SMI, and 7,500 mg/L for IOC-M at a contact time of 60 min. At these optimal doses, the rate constants of the adsorbents were 3.9, 2.6, 2.5, 1.9, 1.8, and 1.6 1/hr for HIOPs, AA, GFH, MIEX, SMI, and IOC-M, respectively. The presence of silicate significantly reduced the arsenic removal efficiency of HIOPs, AA, and GFH, presumably due to the decrease in chemical binding affinity of arsenic in the presence of silicate. Additional experiments with natural types of water showed that, with the exception of IOC-M, the adsorbents had lower adsorption capacities in ground water than with surface and deionized water, in which the adsorption capacities decreased by approximately 60–95 % .

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

    International Nuclear Information System (INIS)

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

  7. Graphene oxide coated coordination polymer nanobelt composite material: a new type of visible light active and highly efficient photocatalyst for Cr(vi) reduction.

    Science.gov (United States)

    Shi, Gui-Mei; Zhang, Bin; Xu, Xin-Xin; Fu, Yan-Hong

    2015-06-28

    A visible light active photocatalyst was synthesized successfully by coating graphene oxide (GO) on a coordination polymer nanobelt (CPNB) using a simple colloidal blending process. Compared with neat CPNB, the resulting graphene oxide coated coordination polymer nanobelt composite material (GO/CPNB) exhibits excellent photocatalytic efficiency in the reduction of K2Cr2O7 under visible light irradiation. In the composite material, GO performs two functions. Firstly, it cuts down the band gap (Eg) of the photocatalyst and extends its photoresponse region from the ultraviolet to visible light region. Secondly, GO exhibits excellent electron transportation ability that impedes its recombination with holes, and this can enhance photocatalytic efficiency. For GO, on its surface, the number of functional groups has a great influence on the photocatalytic performance of the resulting GO/CPNB composite material and an ideal GO"coater" to obtain a highly efficient GO/CPNB photocatalyst has been obtained. As a photocatalyst that may be used in the treatment of Cr(vi) in wastewater, GO/CPNB exhibited outstanding stability during the reduction of this pollutant. PMID:25997385

  8. Fundamental investigation on titanic acid-cordierite composite adsorbent

    International Nuclear Information System (INIS)

    A fundamental investigation was made on the adsorbent of uranium in sea-water for various titanic acid composite types. From the results of the experiment, the adsorption capacity of titanic acid-impregnated cordierite was increased to 1,900 ?g-U/g titanic acid when the concentration of uranium in sea-water was less than 0.1 ?g/l. A feasibility study was tried for 200 ton-U/ year plant by honeycomb-shape adsorbent by using an ocean current, and it was proposed that many adsorbent forms with air tank were arranged as the teeth of a saw on the sea surface. (author)

  9. Dual-protection of a graphene-sulfur composite by a compact graphene skin and an atomic layer deposited oxide coating for a lithium-sulfur battery

    Science.gov (United States)

    Yu, Mingpeng; Wang, Aiji; Tian, Fuyang; Song, Hongquan; Wang, Yinshu; Li, Chun; Hong, Jong-Dal; Shi, Gaoquan

    2015-03-01

    A reduced graphene oxide (rGO)-sulfur composite aerogel with a compact self-assembled rGO skin was further modified by an atomic layer deposition (ALD) of ZnO or MgO layer, and used as a free-standing electrode material of a lithium-sulfur (Li-S) battery. The rGO skin and ALD-oxide coating worked as natural and artificial barriers to constrain the polysulfides within the cathode region. As a result, the Li-S battery based on this electrode material exhibited superior cycling stability, good rate capability and high coulombic efficiency. Furthermore, ALD-ZnO coating was tested for performance improvement and found to be more effective than ALD-MgO coating. The ZnO modified G-S electrode with 55 wt% sulfur loading delivered a maximum discharge capacity of 998 mA h g-1 at a current density of 0.2 C. A high capacity of 846 mA h g-1 was achieved after charging/discharging for 100 cycles with a coulombic efficiency of over 92%. In the case of using LiNO3 as a shuttle inhibitor, this electrode showed an initial discharge capacity of 796 mA h g-1 and a capacity retention of 81% after 250 cycles at a current density of 1 C with an average coulombic efficiency higher than 99.7%.A reduced graphene oxide (rGO)-sulfur composite aerogel with a compact self-assembled rGO skin was further modified by an atomic layer deposition (ALD) of ZnO or MgO layer, and used as a free-standing electrode material of a lithium-sulfur (Li-S) battery. The rGO skin and ALD-oxide coating worked as natural and artificial barriers to constrain the polysulfides within the cathode region. As a result, the Li-S battery based on this electrode material exhibited superior cycling stability, good rate capability and high coulombic efficiency. Furthermore, ALD-ZnO coating was tested for performance improvement and found to be more effective than ALD-MgO coating. The ZnO modified G-S electrode with 55 wt% sulfur loading delivered a maximum discharge capacity of 998 mA h g-1 at a current density of 0.2 C. A high capacity of 846 mA h g-1 was achieved after charging/discharging for 100 cycles with a coulombic efficiency of over 92%. In the case of using LiNO3 as a shuttle inhibitor, this electrode showed an initial discharge capacity of 796 mA h g-1 and a capacity retention of 81% after 250 cycles at a current density of 1 C with an average coulombic efficiency higher than 99.7%. Electronic supplementary information (ESI) available: Procedures of ALD operation, supplementary figures and details of theoretical simulations. See DOI: 10.1039/c5nr00166h

  10. REVIEW: USE of COMPOSITE ADSORBENTS in ADSORPTION REFRIGERATION

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    Satishchandra V. Joshi

    2012-01-01

    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.

  11. Uranium extraction from sea water with composite adsorbents, (3)

    International Nuclear Information System (INIS)

    Measurements were made of the extent of magnetization shown by composite hydrous titanium (IV)-iron (II) oxide adsorbents for use in uranium extraction from sea water. The possibility of removing the adsorbent by means of high-gradient magnetic separation was demonstrated by calculations based on a force balance model. Removal experiments were also carried out, which demonstrated that the composite hydrous oxide can be trapped effectively: A composite hydrous oxide with 1:1 Ti-to-Fe mole ratio, of 400 -- 625 mesh particle size, proved to be removed to 99.9% by a magnetic field of 2.5 kOe, with the slurry flowing at 20 cm/s through a filter matrix 50 cm long packed to 90% void with 100 ?m diameter nickel wire stuffing. Together with the evaluations made of the electric power consumed by the high-gradient magnetic separators, the experimental results indicated the possibility of economically extracting uranium from sea water using these separators in combination with magnetic adsorbents. (author)

  12. Adsorption Characterization of Strontium on PAN/Zeolite Composite Adsorbent

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    Sabriye Yusan

    2011-04-01

    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.

  13. Oxide coating development

    Energy Technology Data Exchange (ETDEWEB)

    Stinton, D.P.

    1995-06-01

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

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

    International Nuclear Information System (INIS)

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

  15. Investigation on titanic acid-cordierite composite adsorbent

    International Nuclear Information System (INIS)

    An investigation was made on the method of preparing uranium adsorbent from titanic acid and cordierite by making the latter impregnate and support the former by the urea method. Also, the relations between the amount of uranium adsorbed in the prepared adsorbent and its property values were investigated. To prepare adsorbent having a high adsorption capacity, it was important for the mother liquid to have pH of around 8 and for the cordierite to have a specific surface area larger than about 700 m2/g per titanic acid. As the result of the above investigations, such conditions as the concentration of titanium, the amount of urea to be added into the prepared solution, etc. necessary for meeting the above requirements were made clear. The amount of uranium adsorbed in the adsorbent measured by a simple method for granular adsorbents after two-day impregnation was 40 to 50 ?g/g when the support had a specific area of 2m2/g and a grain size of 0.35 to 0.42 mm. In case the support having a specific surface area of 8m2/g was used, the adsorbent showed the possibility of saturated adsorption up to approximately 600?g/g. This granular adsorbent was found suitable for use in a fluidizing adsorption equipment. Therefore, a recovery plant of uranium from sea-water by the dispersion and deposition method was shown as an example of its application. (author)

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

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

    2009-07-01

    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.

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

    Energy Technology Data Exchange (ETDEWEB)

    Habibzadeh, Sajjad [Department of Chemical Engineering, McGill University, Montreal, QC (Canada); Li, Ling [Department of Anatomy and Cell Biology, McGill University, Montreal, QC (Canada); Omanovic, Sasha [Department of Chemical Engineering, McGill University, Montreal, QC (Canada); Shum-Tim, Dominique [Divisions of Cardiac Surgery and Surgical Research, Department of Surgery, McGill University, Montreal, QC (Canada); Davis, Elaine C., E-mail: elaine.davis@mcgill.ca [Department of Anatomy and Cell Biology, McGill University, Montreal, QC (Canada)

    2014-05-01

    Graphical abstract: - Highlights: • Ir/Ti-oxide coated surfaces are characterized by the so-called “cracked-mud” morphology. • 40% Ir in the coating material results in a morphologically uniform coating. • ECs and SMCs showed a desirable response to the Ir/Ti-oxide coated surfaces. • Ir/Ti-oxide coated surfaces are more bio/hemocompatible than the untreated 316L stainless steel. - Abstract: 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 Ir{sub x}Ti{sub 1?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 Ir{sub 0.2}Ti{sub 0.8}-oxide and Ir{sub 0.4}Ti{sub 0.6}-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 Ir{sub 0.2}Ti{sub 0.8}-oxide and Ir{sub 0.4}Ti{sub 0.6}-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.

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

    International Nuclear Information System (INIS)

    Graphical abstract: - Highlights: • Ir/Ti-oxide coated surfaces are characterized by the so-called “cracked-mud” morphology. • 40% Ir in the coating material results in a morphologically uniform coating. • ECs and SMCs showed a desirable response to the Ir/Ti-oxide coated surfaces. • Ir/Ti-oxide coated surfaces are more bio/hemocompatible than the untreated 316L stainless steel. - Abstract: 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

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

    International Nuclear Information System (INIS)

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

  20. Polytetrafluoroethylene/TiO2 Composite Pellets as Sulfur Adsorbents for Pressure Oxidation Leaching of Chalcopyrite

    Science.gov (United States)

    Govindaiah, Patakamuri; Grundy, Mark; Guerra, Eduard; Choi, Yeonuk; Ye, Zhibin

    2015-01-01

    In this study, we report the use of polytetrafluoroethylene/titanium dioxide (PTFE/TiO2) composite pellets as sulfur adsorbents in the extraction of copper from chalcopyrite by pressure oxidation leaching. PTFE/TiO2 composites of various compositions were prepared by compression molding followed by pelletization. The mass percentage of TiO2 filler in the PTFE matrix was varied from 0 to 35 wt pct. With the use of the composite pellets, significant enhancements in copper leaching were observed, indicating their role as adsorbents for the adsorption of molten elemental sulfur. In particular, the enhancement in copper extraction was increasingly pronounced (from 75 to 89 pct) with the increase of the mass percentage of TiO2 in the composite pellets from 0 to 35 wt pct. This is reasoned to result from the loss of TiO2 domains from the pellet surface, which creates additional rough hydrophobic surface to better capture elemental sulfur. The composite pellet adsorbents show excellent reusability, with the performance well maintained for 10 leaching cycles. In addition, the effectiveness of composite adsorbents at different chalcopyrite pulp densities was also investigated.

  1. 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

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

    Scientific Electronic Library Online (English)

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

    2012-03-01

    Full Text Available In this work, Microsilica, one kind of industry solid waste material, was utilized firstly to prepare a carbon-Microsilica composite adsorbent from a partial carbonization, mixture and sulfoxidation process and was proposed for the removal of Cr(VI) from solutions. The surface chemistry 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.

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

    Directory of Open Access Journals (Sweden)

    DEYI ZHANG

    2012-03-01

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

  4. Barium strontium oxide coated carbon nanotubes as field emitters

    Science.gov (United States)

    Jin, Feng; Liu, Yan; Day, Christopher M.

    2007-04-01

    The authors report a field emitter structure based on oxide coated carbon nanotubes (CNTs). This emitter consists of a thin tungsten ribbon with CNTs on the surface and a thin layer of low work function barium strontium oxide coating on the CNTs. This oxide coated CNT emitter was designed to combine the benefits of the high field enhancement factor from CNTs and the low work function from the emissive oxide coating. The field emission properties of the emitters were characterized. A field enhancement factor of 467 and a work function of 1.9eV were obtained for the oxide coated CNTs. Compared to the uncoated CNTs, the field emission from the oxide coated CNTs increased by a factor of 2-3. At 4.4V/?m, the field emission current of 23.6?A was obtained from an emitting surface of 0.012cm2.

  5. Raman and IR spectroscopic investigation of As adsorbed on Mn3O4 magnetic composites

    Science.gov (United States)

    Silva, Gabriela C.; Almeida, Fabiana S.; Dantas, Maria Sylvia S.; Ferreira, Angela M.; Ciminelli, Virginia S. T.

    Raman and IR spectra were recorded of the As-loaded Mn3O4 magnetic composites obtained from the adsorption studies performed with As(III). XANES results for the composite after As(III) removal tests show that the As adsorbed is at the oxidized arsenic form, As(V). Monodentate and bidentate surface complexes are suggested for arsenic adsorption onto the composite (5-16 mg/g). Precipitation of manganese arsenate is observed for high As loading (35 mg/g).

  6. Modeling of fixed-bed column studies for the adsorption of cadmium onto novel polymer-clay composite adsorbent

    International Nuclear Information System (INIS)

    Kaolinite clay was treated with polyvinyl alcohol to produce a novel water-stable composite called polymer-clay composite adsorbent. The modified adsorbent was found to have a maximum adsorption capacity of 20,400 ± 13 mg/L (1236 mg/g) and a maximum adsorption rate constant of ?7.45 x 10-3 ± 0.0002 L/(min mg) at 50% breakthrough. Increase in bed height increased both the breakpoint and exhaustion point of the polymer-clay composite adsorbent. The time for the movement of the Mass Transfer Zone (?) down the column was found to increase with increasing bed height. The presence of preadsorbed electrolyte and regeneration were found to reduce this time. Increased initial Cd2+ concentration, presence of preadsorbed electrolyte, and regeneration of polymer-clay composite adsorbent reduced the volume of effluent treated. Premodification of polymer-clay composite adsorbent with Ca- and Na-electrolytes reduced the rate of adsorption of Cd2+ onto polymer-clay composite and lowered the breakthrough time of the adsorbent. Regeneration and re-adsorption studies on the polymer-clay composite adsorbent presented a decrease in the bed volume treated at both the breakpoint and exhaustion points of the regenerated bed. Experimental data were observed to show stronger fits to the Bed Depth Service Time (BDST) model than the Thomas model.

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

    Energy Technology Data Exchange (ETDEWEB)

    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

    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)

  8. DPPG Liposomes Adsorbed on Polymer Cushions: Effect of Roughness on Amount, Surface Composition and Topography.

    Science.gov (United States)

    Duarte, Andreia A; Botelho do Rego, Ana M; Salerno, Marco; Ribeiro, Paulo A; El Bari, Nezha; Bouchikhi, Benachir; Raposo, Maria

    2015-07-01

    The adsorption of intact liposomes onto solid supports is a fundamental issue when preparing systems with encapsulated biological molecules. In this work, the adsorption kinetic of 1,2-dipalmitoyl-sn-glycero-3-[phospho-rac-(1-glycerol)] (sodium salt) liposomes onto cushions prepared from commom polyelectrolytes by the layer-by-layer technique was investigated with the main objective of finding the surface conditions leading to the adsorption of intact liposomes. For this purpose, different cushion surface roughnesses were obtained by changing the number of cushion bilayers. The adsorbed amount per unit area was measured through quartz crystal microbalance, surface morphology was characterized by atomic force microscopy, and the surface composition was assessed by X-ray photoelectron spectroscopy. The results show that (1) the amount of adsorbed lipids depends on the number of cushion bilayers, (2) the cushions are uniformly covered by the adsorbed lipids, and (3) the surface morphology of polymer cushions tunes liposome rupture and its adsorption kinetics. The fraction of ruptured liposomes, calculated from the measured amount of adsorbed lipids, is a function of surface roughness together with other surface morphology parameters, namely the dominating in-plane spatial feature size, the fractal dimension, and other textural features as well as amplitude and hybrid parameters. PMID:26076391

  9. Removal of hydrogen sulfide at ambient conditions on cadmium/GO-based composite adsorbents.

    Science.gov (United States)

    Florent, Marc; Wallace, Rajiv; Bandosz, Teresa J

    2015-06-15

    Cadmium-based materials with various hydroxide to carbonate ratios and their composites with graphite oxide were synthesized by a fast and simple precipitation procedure and then used as H2S adsorbents at ambient conditions in the dark or upon a visible light exposure. The structural properties and chemical features of the adsorbents were analyzed before and after hydrogen sulfide adsorption. The results showed that the high ratio of hydroxide to carbonate led to an improved H2S adsorption capacity. In moist conditions cadmium hydroxide was the best adsorbent. Moreover, it showed photoactive properties. While the incorporation of a graphene-based phase slightly decreased the extent of the improvement in the H2S adsorption capacity in moist conditions caused by photoactivity, its presence in the composites enhanced the performance in dry conditions. This was linked to photoactivity of CdS that can split H2S resulting in the formation of water in the system. The graphene-based phase enhanced the electron transfer and delayed the recombination of photoinduced charges. Carbonate-based materials showed a very good adsorption capacity in dark conditions in the presence of moisture. Upon the light exposure, CdS likely photocatalyzes the reduction of carbonate ions to formates/formaldehydes. Their deposition on the surface limits the number of sites available to H2S adsorption. PMID:25792480

  10. Attapulgite based LiCl composite adsorbents for cooling and air conditioning applications

    International Nuclear Information System (INIS)

    A series of attapulgite-based LiCl composites were prepared with mixing method, incorporating hygroscopic LiCl into porous surface of attapulgite clay. Sorption properties of these composites were performed with high vacuum gravimetric method, desorption performance by TG-DTA analysis, and characterization by X-ray diffraction. The results show that both attapulgite structure and chloride content play prime roles in water adsorption on the AT-LiCl adsorbents, especially during lower water pressure, while at higher pressure, adsorption performances strongly depend on chloride content. At 1500 Pa, water loading on AT-LiCl (30%) can be as high as 0.44 kg/kg, while at 750 Pa, the loading is 0.31 kg/kg, which is higher than commonly used zeolite 13X and silica gel. Based on sorption equilibrium curves, isosteric heat is calculated. This study shows that intension of water sorption on composite adsorbent is intermediate between that on zeolite 13X and silica gel. The composites can be effectively regenerated during 170-190 deg. C. AT-LiCl (30%) seems to be an efficient candidate for cooling or air conditioning applications, specially when utilization of heat sources at temperatures lower than 170 deg. C

  11. Testing and evaluation of oxide-coated iridium/rhenium chambers

    Science.gov (United States)

    Reed, Brian D.

    1993-01-01

    Iridium-coated rhenium provides long life operation of radiation-cooled rockets at temperatures up to 2200 C. Ceramic oxide coatings could be used to increase iridium/rhenium rocket lifetimes and allow operation in highly oxidizing environments. Ceramic oxide coatings promise to serve as both thermal and diffusion barriers for the iridium layer. Seven ceramic oxide-coated iridium/rhenium, 22 N rocket chambers were tested on gaseous hydrogen/gaseous oxygen propellants. Five chambers had thick (over 10 mils), monolithic coatings of either hafnia or zirconia. Two chambers had coatings with thicknesses less than 5 mils. One of these chambers had a thin-walled coating of zirconia infiltrated with sol gel hafnia. The other chamber had a coating composed of an iridium/oxide composite. The purpose of this test program was to assess the ability of the oxide coatings to withstand the thermal shock of combustion initiation, adhere under repeated thermal cycling, and operate in aggressively oxidizing environments. All of the coatings survived the thermal shock of combustion and demonstrated operation at mixture ratios up to 11. The iridium/oxide composite coated chamber included testing for over 29 minutes at mixture ratio 16. The thicker-walled coatings provided the larger temperature drops across the oxide layer (up to 570 C), but were susceptible to macrocracking and eventual chipping at a stress concentrator. The cracks apparently resealed during firing, under compression of the oxide layer. The thinner-walled coatings did not experience the macrocracking and chipping of the chambers seen with the thick, monolithic coatings. However, burnthroughs in the throat region did occur in both of the thin-walled chambers at mixture ratios well above stochiometric. The burn-throughs were probably the result of oxygen-diffusion through the oxide coating that allowed the underlying iridium and rhenium layers to be oxidized. The results of this test program indicated that the thin-walled oxide coatings are better suited for repeated thermal cycling than the thick-walled coating, while thicker coatings may be required for operation in aggressively oxidizing environments.

  12. Long Life Testing of Oxide-Coated Iridium/Rhenium Rockets

    Science.gov (United States)

    Reed, Brian D.

    1995-01-01

    22-N class rockets, composed of a rhenium (Re) substrate, an iridium (Ir) coating, and an additional composite coating consisting of Ir and a ceramic oxide, were tested on gaseous oxygen/gaseous hydrogen (GO2/GH2) propellants. Two rockets were tested, one for nearly 39 hours at a nominal mixture ratio (MR) of 4.6 and chamber pressure (Pc) of 469 kPa, and the other for over 13 hours at a nominal MR of 5.8 and 621 kPa Pc. Four additional Ir/Re rockets, with a composite Ir-oxide coating fabricated using a modified process, were also tested, including one for 1.3 hours at a nominal MR of 16.7 and Pc of 503 kPa. The long lifetimes demonstrated on low MR GO2/GH2 suggest greatly extended chamber lifetimes (tens of hours) in the relatively low oxidizing combustion environments of Earth storable propellants. The oxide coatings could also serve as a protective coating in the near injector region, where a still-mixing flowfield may cause degradation of the Ir layer. Operation at MR close to 17 suggests that oxide-coated Ir/Re rockets could be used in severely oxidizing combustion environments, such as high MR GO2/GH2, oxygen/hydrocarbon, and liquid gun propellants.

  13. Arsenic Removal from Aqueous Solutions Using Fe3O4-HBC Composite: Effect of Calcination on Adsorbents Performance

    OpenAIRE

    Baig, Shams Ali; Sheng, TianTian; Sun, Chen; Xue, XiaoQin; Tan, LiSha; Xu, XinHua

    2014-01-01

    The presence of elevated concentration of arsenic in water sources is considered to be health hazard globally. Calcination process is known to change the surface efficacy of the adsorbent. In current study, five adsorbent composites: uncalcined and calcined Fe3O4-HBC prepared at different temperatures (400°C and 1000°C) and environment (air and nitrogen) were investigated for the adsorptive removal of As(V) and As(III) from aqueous solutions determining the influence of solution's pH, conta...

  14. Characteristics of cobalt adsorption on titanium(IV) oxide-alumina composite adsorbents in high temperature water

    International Nuclear Information System (INIS)

    Titanium(IV) oxide-alumina composite adsorbents were prepared by hydrolysis of titanium (IV) and aluminum isopropoxide followed by drying and calcining their hydroxides, and their cobalt adsorption in high-temperature water was investigated. The adsorbent composed of titanium(IV) oxide and alumina, being 0.55 in mole fraction of titanium(IV) oxide and calcined at 500 0C for 5 h showed a surface area of 124 m2.g-1 and an equilibrium adsorption capacity of 110 ?eq.g-1 at 280 0C in a pH 4.45 solution containing cobalt ion at 3 ppm. The specific surface area of the composite adsorbent decreasea with increasing mole fraction of titanium(IV) oxide. However, the cobalt adsorption capacity at 280 0C increased with the titanium(IV) oxide mole fraction. Therefore, the cobalt adsorption in high temperature water seems to be controlled by titanium(IV) oxide in the composite adsorbent. From the measured adsorption capacity, it appears that a high specific surface area of titanium(IV) oxide in the adsorbent is maintained even when the adsorbent is calcined at the sintering temperature of titanium(IV) oxide. (author)

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

    Science.gov (United States)

    Ceylan, ?eyda; Odaba??, Mehmet

    2013-12-01

    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

  16. Adsorption character for removal Cu(II) by magnetic Cu(II) ion imprinted composite adsorbent

    International Nuclear Information System (INIS)

    A novel magnetic Cu(II) ion imprinted composite adsorbent (Cu(II)-MICA) was synthesized, characterized and applied for the selective removal Cu(II) from aqueous solution in the batch system. The adsorption-desorption and selectivity characteristics were investigated. The maximum adsorption occurred at pH 5-6. The equilibrium time was 6.0 h, and a pseudo-second-order model could best describe adsorption kinetics. The adsorption equilibrium data fit Langmuir isotherm equation well with a maximum adsorption capacity of 46.25 mg/g and Langmuir adsorption equilibrium constant of 0.0956 L/mg at 298 K. Thermodynamic parameters analysis predicted an exothermic nature of adsorption and a spontaneous and favourable process that could be mainly governed by physisorption mechanism. The relative selectivity coefficients of Cu(II)-MICA for Cu(II)/Zn(II) and Cu(II)/Ni(II) were 2.31, 2.66 times greater than the magnetic non-imprinted composite adsorbent (MNICA). Results suggested that Cu(II)-MICA was a material of efficient, low-cost, convenient separation under magnetic field and could be reused five times with about 14% regeneration loss

  17. Synthesis, structural and mechanical characterization of sputtered tungsten oxide coatings

    International Nuclear Information System (INIS)

    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 (p O2/p Ar) 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 ?-W and ?-W3O phases were observed ( 75 at.%, a nanocrystalline (WO3) structure was reached. The hardness and Young's modulus were evaluated by depth sensing indentation. The decrease in hardness followed the four different ranges of chemical compositions accordingly, from ? 23 GPa for pure W down to ? 7 GPa for WO3 films. A similar behaviour was observed for the Young's modulus, which ranged from 450 GPa to 150 GPa. The cohesion/adhesion of the films were investigated using a scratch-test apparatus. These coatings displayed a low adhesion (critical load, L c < 15 N) to the steel substrate because the depositions were carried out intentionally without an adhesion interfacial layer

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

    Science.gov (United States)

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

    1999-01-01

    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.

  19. Alumina-Activated Carbon Composite as Adsorbent of Procion Red Dye from Wastewater Songket Industry

    Directory of Open Access Journals (Sweden)

    Poedji Loekitowati Hariani

    2015-03-01

    Full Text Available Alumina-activated carbon composite has been synthesized and studied for adsorption procion red dye. Composite was prepared by precipitation method aluminium hydroxide on the surface of activated carbon followed by calcinations. The Fourier transform Infra Red (FTIR, Scanning Electron Microscopy-Energy Dispersive X-Ray Spectroscopy (SEM-EDS and Brunaeur Emmet Teller (BET surface are being used to characterize the adsorbent. Batch adsorption experiments were carried out for the adsorption of procion red dye. Effect of the mass of composite, stirrer speed, contact times and pH of the solution on the adsorption capacity were studied. The obtained optimum conditions applied to adsorp of procion red dye from wastewater songket industry. The result showed that the adsorption optimum at mass of alumina-activated carbon composite 0.1 g, stirrer speed 150 rpm, contact times 2 hours at pH of the solution 9. The adsorption isotherm data according to Langmuir isotherm. The alumina-activated carbon composite can be removal of procion red dye from wastewater songket industry with effectiveness adsorption of 88.21 %.

  20. Ultimate selenium(IV) monitoring and removal from water using a new class of organic ligand based composite adsorbent.

    Science.gov (United States)

    Awual, Md Rabiul; Yaita, Tsuyoshi; Suzuki, Shinichi; Shiwaku, Hideaki

    2015-06-30

    This work reports the selenium (Se(IV)) detection and removal from water by ligand functionalized organic-inorganic based novel composite adsorbent. The composite adsorbent was prepared by direct immobilization of N,N'-di(3-carboxysalicylidene)-3,4-diamino-5-hydroxypyrazole onto the mesoporous silica monolith. The adsorbent exhibited distinct color change in the presence of various concentrations of Se(IV). This was characterized by UV-vis spectroscopy, and the color change was observed by naked-eye observation. The detection limit was determined to be 1.14?g/L. The effect of solution pH, interferential metal ions, contact time, initial Se(IV) concentration, and adsorbent regeneration were evaluated. The maximum sorption capacity was determined based on the initial concentration. The data fitted well to the Langmuir isotherm model, and the maximum Se(IV) sorption capacity was 111.12mg/g. The presence of diverse competing ions did not affect the Se(IV) sorption capacity, and the adsorbent had almost no sorption capacity for these coexisting ions, which suggests the high selectivity to Se(IV) ions. The adsorbed Se(IV) was eluted with suitable eluent (0.10M NaOH) and simultaneously regenerated into the initial form for the next operation. The excellent reusability of the adsorbent was justified after eight consecutive sorption-elution-regeneration cycles. The proposed adsorbent is cost-effective and environmentally friendly and a potential candidate for treatment of water containing Se(IV). PMID:25771216

  1. Comparative Study on Kinetics of Chlorine Evolution Reaction for Ru-La-O Oxide Coatings

    Directory of Open Access Journals (Sweden)

    LONG Ping, XU Li-Kun, CUI Xiu-Fang, JIN Guo

    2015-05-01

    Full Text Available The Ti/RuO2 and Ti/Ru-La-O oxide coatings were prepared by thermal decomposition of the metal chlorides in the precursor solution. The specific adsorption of Cl? on coatings, the effect of La on the chlorine evolution reactions (ClER and the kinetic mechanism were investigated by using differential capacity (DC and polarization curves (PC. Results show that the coating surface exhibits significantly specific adsorption of Cl? in NaCl neutral solution, which has an influence on the kinetics of the chlorine evolution process, resulting in an increase of the Tafel slope and a decrease of the reaction order. The addition of lanthanum reduces the overpotential of Ti/RuO2 coating and enhances the exchange current density, which improves the chlorine evolution reaction of the coatings. Both kinetic mechanisms of recombination and electrochemical desorption of adsorbed intermediate species for the coatings are comparatively studied. It is confirmed that the Chlorine evolution reaction on Ru-La-O oxide coatings in NaCl neutral solution is controlled by the process of.

  2. Preparing oxidizer coated metal fuel particles

    Science.gov (United States)

    Shafer, J. I.; Simmons, G. M. (inventors)

    1974-01-01

    A solid propellant composition of improved efficiency is described which includes an oxidizer containing ammonium perchlorate, and a powered metal fuel, preferably aluminum or beryllium, in the form of a composite. The metal fuel is contained in the crystalline lattice framework of the oxidizer, as well as within the oxidizer particles, and is disposed in the interstices between the oxidizer particles of the composition. The propellant composition is produced by a process comprising the crystallization of ammonium perchlorate in water, in the presence of finely divided aluminum or beryllium. A suitable binder is incorporated in the propellant composition to bind the individual particles of metal with the particles of oxidizer containing occluded metal.

  3. Electrochemical combustion of indigo at ternary oxide coated titanium anodes

    Directory of Open Access Journals (Sweden)

    María I. León

    2014-12-01

    Full Text Available The film of iridium and tin dioxides doped with antimony (IrO2-SnO2–Sb2O5 deposited on a Ti substrate (mesh obtained by Pechini method was used for the formation of ·OH radicals by water discharge. Detection of ·OH radicals was followed by the use of the N,N-dimethyl-p-nitrosoaniline (RNO as a spin trap. The electrode surface morphology and composition was characterized by SEM-EDS. The ternary oxide coating was used for the electrochemical combustion of indigo textile dye as a model organic compound in chloride medium. Bulk electrolyses were then carried out at different volumetric flow rates under galvanostatic conditions using a filter-press flow cell. The galvanostatic tests using RNO confirmed that Ti/IrO2-SnO2-Sb2O5 favor the hydroxyl radical formation at current densities between 5 and 7 mA cm-2, while at current density of 10 mA cm-2 the oxygen evolution reaction occurs. The indigo was totally decolorized and mineralized via reactive oxygen species, such as (·OH, H2O2, O3 and active chlorine formed in-situ at the Ti/IrO2-SnO2-Sb2O5 surface at volumetric flow rates between 0.1-0.4 L min-1 and at fixed current density of 7 mA cm-2. The mineralization of indigo carried out at 0.2 L min-1 achieved values of 100 %, with current efficiencies of 80 % and energy consumption of 1.78 KWh m-3.

  4. Improved transmittance measurement with a magnesium oxide coated integrating sphere

    Science.gov (United States)

    Bowman, R. L.; Spisz, E. W.

    1972-01-01

    Simple and convenient technique has been found for extending transmittance measurement capability of conventional magnesium oxide coated integrating sphere system at low (near ultraviolet) wavelengths. Technique can be used to determine effect of contaminants on window materials and can also be used for measurements on thermal control coatings and telescope mirrors.

  5. Application of Carbon Composite Adsorbents Prepared from Coffee Waste and Clay for the Removal of Reactive Dyes from Aqueous Solutions

    Scientific Electronic Library Online (English)

    Davis C. dos, Santos; Matthew A., Adebayo; Eder C., Lima; Simone F. P., Pereira; Renato, Cataluña; Caroline, Saucier; Pascal S., Thue; Fernando M., Machado.

    2015-05-01

    Full Text Available A novel carbon composite was prepared from a mixture of coffee waste and clay with inorganic:organic ratio of 1.3 (CC-1.3). The mixture was pyrolysed at 700 °C. Considering the application of this adsorbent for removal of anionic dyes, the CC-1.3 was treated with a 6 mol L-1 HCl for 24 h to obtain A [...] CC-1.3. Fourier transform infrared (FTIR), N2 adsorption/desorption curves, scanning electron microscope (SEM) and powder X-ray diffractometry (XRD) were used for characterisation of CC-1.3 and ACC-1.3 carbon adsorbents. The adsorbents were effectively utilised for removal of reactive blue 19 (RB-19) and reactive violet 5 (RV-5) textile dyes from aqueous solutions. The maximum amounts of RB-19 dye adsorbed at 25 °C are 63.59 (CC-1.3) and 110.6 mg g-1 (ACC-1.3), and 54.34 (CC-1.3) and 94.32 mg g-1 (ACC-1.3) for RV-5 dye. Four simulated dye-house effluents were used to test the application of the adsorbents for treatment of effluents.

  6. Engineering the surface of a new class of adsorbents: metal-organic framework/graphite oxide composites.

    Science.gov (United States)

    Petit, Camille; Bandosz, Teresa J

    2015-06-01

    This paper reviews the results of several prior studies to highlight how the concept of the metal-organic framework/graphite oxide (MOF/GO) composites was developed towards their application as separation media for small molecule gases at ambient conditions. The studies are analyzed from a surface engineering standpoint. The MOF/GO composites have been developed considering both the advantages and drawbacks of the composite components: MOF provided a high porosity and reactive centers and GO a dense array of carbon atoms to increase dispersive interactions. The resulting materials showed a significant enhancement in porosity owing to the formation of pores at the interface of GO and MOF crystals. GO oxygen groups were identified as nucleation sites for the formation of the MOF crystals. Other heteroatoms like N also contributed to that effect and could positively enhance the composites structural/chemical heterogeneity. That heterogeneity governed the excellent performance of the composites as reactive adsorbents of NH3, H2S, NO2 and physical adsorbents of CO2 at ambient conditions. While the MOF structure collapsed upon exposure to toxic gases, it was preserved after CO2 adsorption indicating the recyclability of these materials. Systematic studies of the composite properties showed that such factors as the GO level of oxidation, flake sizes of a graphite precursor and the geometry of MOF crystals are of paramount importance dictating the final morphology of the composite. The properties of the composites make them potentially suitable for gas sensing or energy harvesting. PMID:25234622

  7. An efficient removal of methyl orange dye from aqueous solution by adsorption onto chitosan/MgO composite: A novel reusable adsorbent

    International Nuclear Information System (INIS)

    We report a novel multi-functional magnesium oxide (MgO) immobilized chitosan (CS) composite was prepared by chemical precipitation method. The CS–MgO composite was characterized by Fourier transform infrared spectroscopy, X-ray diffraction, transmission electron microscopy and zeta potential. The composite was applied as a novel adsorbent for removal of methyl orange model dye and the effect of adsorbent dosage, pH and contact time were studied. The adsorption kinetics followed a pseudo second order reaction. The adsorbent efficiency was unaltered even after five cycles of reuse. In addition, the composite exhibited a superior antibacterial efficacy of 93% within 24 h against Escherichia coli as measured by colony forming units. Based on the data of present investigation the composite being a biocompatible, eco-friendly and low-cost adsorbent with antibacterial activity could find potential applications in variety of fields and in particular environmental applications.

  8. An efficient removal of methyl orange dye from aqueous solution by adsorption onto chitosan/MgO composite: A novel reusable adsorbent

    Energy Technology Data Exchange (ETDEWEB)

    Haldorai, Yuvaraj; Shim, Jae-Jin, E-mail: jjshim@yu.ac.kr

    2014-02-15

    We report a novel multi-functional magnesium oxide (MgO) immobilized chitosan (CS) composite was prepared by chemical precipitation method. The CS–MgO composite was characterized by Fourier transform infrared spectroscopy, X-ray diffraction, transmission electron microscopy and zeta potential. The composite was applied as a novel adsorbent for removal of methyl orange model dye and the effect of adsorbent dosage, pH and contact time were studied. The adsorption kinetics followed a pseudo second order reaction. The adsorbent efficiency was unaltered even after five cycles of reuse. In addition, the composite exhibited a superior antibacterial efficacy of 93% within 24 h against Escherichia coli as measured by colony forming units. Based on the data of present investigation the composite being a biocompatible, eco-friendly and low-cost adsorbent with antibacterial activity could find potential applications in variety of fields and in particular environmental applications.

  9. Preparation of Nano Iron Oxide Coated Activated Sludge Granules and its Adsorption Properties for Cd (II Ions in Aqueous Solutions

    Directory of Open Access Journals (Sweden)

    Muhammad Hashemifar

    2014-05-01

    Full Text Available The purpose of this study is Preparation of nano iron oxide coated activated sludge granules and its adsorption properties for Cd (II ions in aqueous solutions. Activated sludge as biosorbent was modified using nano iron oxide coating and examined for removal of cadmium ions from aqueous solutions. The effect of parameters including amount of coating, contact time, solution pH, initial Cd concentration and adsorbent dosage was evaluated in batch experiments. The results showed that percentage removal of 91.6 was achieved by using modified sludge at alkaline pH 9 and contact time 120 min. The uptake of cadmium was best described by Langmuir-Freundlich isotherms. The kinetic study revealed that Cd (II adsorption was in agreement with pseudo second-order equation. The Cd (II loaded and unloaded granules were analyzed using Scanning Electron Microscopy (SEM and Fourier transform infrared spectroscopy (FTIR. Based on the obtained results, the modified activated sludge granules with nano iron oxide are an efficient adsorbent for removal of cadmium ions as inorganic water and wastewater pollutant.

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

    Science.gov (United States)

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

    2013-08-01

    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

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

    OpenAIRE

    Marek DZIENIEWICZ; Henryk SECHMAN; Maciej J. KOTARBA

    2009-01-01

    The near-surface geochemical survey of gases desorbed from sediment samples was carried out in the area of an abandoned ozokerite mine in Starunia, where remnants of mammoth and three woolly rhinoceroses and one almost completely preserved rhinoceros carcass were discovered in 1907 and 1929. Numerous hydrocarbon seeps (gas and oil "eyes") occur on the surface of the study area. Analyses of molecular and stable carbon isotope compositions of adsorbed gases were carried out in two variants. The...

  12. Versatile wet deposition techniques for functional oxide coatings

    OpenAIRE

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

    2004-01-01

    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...

  13. Electrochemical Deposition of Nanostructured Metal/Metal-Oxide Coatings

    OpenAIRE

    Eskhult, Jonas

    2007-01-01

    Electrochemical deposition finds applications in the electronics- and protective coating industries. The technique is a versatile tool for the synthesis of alloys and thin films. Knowledge of the fundamental aspects of the electrode processes enables the design of nanostructured materials. In this thesis, electrodeposition processes in solutions containing metal ion complexes were studied and new methods for the preparation of metal/metal-oxide coatings were developed and evaluated. Metal/met...

  14. The mechanical properties of metal oxide coated polyester films

    OpenAIRE

    Henry, BM; Howells, D.; Assender, HE; Grovenor, CRM

    2006-01-01

    This communication reports on a study of the microstructure, mechanical and gas barrier properties of PECVD metal oxide coatings on heat stabilised (HS) PET [poly(ethylene terephthalate)], primer-coated HS PET, filled PET and PEN [poly(ethylene naphthalate)] substrates. The coatings are highly conformal and exhibit very few large scale defects. Internal stresses in the coatings are found to be compressive for all substrates. The substrate is found to influence some of the mechanical propertie...

  15. Effects of MAR-M247 substrate (modified) composition on coating oxidation coating/substrate interdiffusion. M.S. Thesis. Final Report; [protective coatings for hot section components of gas turbine engines

    Science.gov (United States)

    Pilsner, B. H.

    1985-01-01

    The effects of gamma+gamma' Mar-M247 substrate composition on gamma+beta Ni-Cr-Al-Zr coating oxidation and coating/substrate interdiffusion were evaluated. These results were also compared to a prior study for a Ni-Cr-Al-Zr coated gamma Ni-Cr-Al substrate with equivalent Al and Cr atomic percentages. Cyclic oxidation behavior at 1130 C was investigated using change in weight curves. Concentration/distance profiles were measured for Al, Cr, Co, W, and Ta. The surface oxides were examined by X-ray diffraction and scanning electron microscopy. The results indicate that variations of Ta and C concentrations in the substrate do not affect oxidation resistance, while additions of grain boundary strengthening elements (Zr, Hf, B) increase oxidation resistance. In addition, the results indicate that oxidation phenomena in gamma+beta/gamma+gamma' Mar-M247 systems have similar characteristics to the l gamma+beta/gamma Ni-Cr-Al system.

  16. 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.

  17. Antibacterial activity of zinc oxide-coated nanoporous alumina

    Energy Technology Data Exchange (ETDEWEB)

    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

    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.

  18. Electron Beam Plasma Application for Synthesis of Bioactive Titanium Oxide Coatings

    Science.gov (United States)

    Vasilieva, T. M.; Sokolov, I. V.; Balakin, K. V.

    2015-03-01

    Prospective bio-medical applications of the electron-beam plasma (EBP) were experimentally studied. The EBP-treated titanium samples were investigated from the point of view of their bio-compatibility. The titanium oxide coatings were synthesized in the EBP of oxygen on the surface of plane titanium substrates and on the inner surface of the titanium tubes. The EBB-treatment was able to signifantly improve the surface uniformity and roughness. Titanium oxide TiO2 (IV) in the rutile form predominated in the coatings composition The bioactivity of synthesized TiO2-coatings was characterized by the water contact angle measurements and by the ability to precipitate hydroxyapatite from the model solution which simulated the composition of the body fluid. The studies showed the samples with plasmachemically synthesized TiO2-coatings to be more hydrophilic than untreated titanium and to precipitate hydroxyapatite on their surface effectively.

  19. Arsenic removal from aqueous solutions using Fe3O4-HBC composite: effect of calcination on adsorbents performance.

    Science.gov (United States)

    Baig, Shams Ali; Sheng, TianTian; Sun, Chen; Xue, XiaoQin; Tan, LiSha; Xu, XinHua

    2014-01-01

    The presence of elevated concentration of arsenic in water sources is considered to be health hazard globally. Calcination process is known to change the surface efficacy of the adsorbent. In current study, five adsorbent composites: uncalcined and calcined Fe3O4-HBC prepared at different temperatures (400°C and 1000°C) and environment (air and nitrogen) were investigated for the adsorptive removal of As(V) and As(III) from aqueous solutions determining the influence of solution's pH, contact time, temperature, arsenic concentration and phosphate anions. Characterizations from FTIR, XRD, HT-XRD, BET and SEM analyses revealed that the Fe3O4-HBC composite at higher calcination temperature under nitrogen formed a new product (fayalite, Fe2SiO4) via phase transformation. In aqueous medium, ligand exchange between arsenic and the effective sorbent site (?=?FeOOH) was established from the release of hydroxyl group. Langmuir model suggested data of the five adsorbent composites follow the order: Fe3O4-HBC-1000°C(N2)>Fe3O4-HBC (uncalcined)>Fe3O4-HBC-400°C(N2)>Fe3O4-HBC-400°C(air)>Fe3O4-HBC-1000°C(air) and the maximum As(V) and As(III) adsorption capacities were found to be about 3.35 mg g(-1) and 3.07 mg g(-1), respectively. The adsorption of As(V) and As(III) remained stable in a wider pH range (4-10) using Fe3O4-HBC-1000°C(N2). Additionally, adsorption data fitted well in pseudo-second-order (R2>0.99) rather than pseudo-first-order kinetics model. The adsorption of As(V) and As(III) onto adsorbent composites increase with increase in temperatures indicating that it is an endothermic process. Phosphate concentration (0.0l mM or higher) strongly inhibited As(V) and As(III) removal through the mechanism of competitive adsorption. This study suggests that the selective calcination process could be useful to improve the adsorbent efficiency for enhanced arsenic removal from contaminated water. PMID:24967645

  20. X-ray Diffraction Studies of the Structure and Thermochemistry of Alkaline-Earth Oxide-Coated Thermionic Cathodes

    Science.gov (United States)

    Karikari, E. K.; Bassey, E.; Wintucky, Edwin G.

    1998-01-01

    NASA LeRC has a broad, active cathode technology development program in which both experimental and theoretical studies are being employed to further development of thermionic cathodes for use as electron sources in vacuum devices for communications and other space applications. One important type of thermionic cathode under development is the alkaline-earth oxide-coated (BaO, SrO, CaO) cathode. Significant improvements in the emission characteristics of this cathode have been obtained through modification of the chemical composition and morphology of the oxide coating, with the best result thus far coming from the addition of In2O3 and Sc2O3. Whereas the In2O3 produces a finer, more uniform particle structure, the exact chemical state and role of the Sc2O3 in the emission enhancement is unknown. The purpose of this cooperative agreement is to combine the studies of the surface chemistry and electron emission at NASA LeRC of chemically modified oxide coatings with a study of the thermochemistry and crystal structure using X-ray diffraction equipment and expertise at Clark Atlanta University (CAU). The study at CAU is intended to provide the description and understanding of the structure and thermochemistry needed for further improvement and optimization of the modified coatings. A description of the experimental procedure, preliminary X-ray diffraction test results, together with the design of an ultrahigh vacuum chamber necessary for high temperature thermochemistry studies will be presented.

  1. Electrochemical properties of inorganic nanoporous oxide coated electrodes

    Science.gov (United States)

    Leonard, Kevin C.

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

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

    Science.gov (United States)

    Le Granvalet-Mancini, Maryline; Teeters, Dale

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

  3. Performance of magnetic activated carbon composite as peroxymonosulfate activator and regenerable adsorbent via sulfate radical-mediated oxidation processes.

    Science.gov (United States)

    Oh, Wen-Da; Lua, Shun-Kuang; Dong, Zhili; Lim, Teik-Thye

    2015-03-01

    Magnetic activated carbon composite (CuFe2O4/AC, MACC) was prepared by a co-precipitation-calcination method. The MACC consisted of porous micro-particle morphology with homogeneously distributed CuFe2O4 and possessed high magnetic saturation moment (8.1 emu g(-1)). The performance of MACC was evaluated as catalyst and regenerable adsorbent via peroxymonosulfate (PMS, Oxone(®)) activation for methylene blue (MB) removal. Optimum CuFe2O4/AC w/w ratio was 1:1.5 giving excellent performance and can be reused for at least 3 cycles. The presence of common inorganic ions, namely Cl(-) and NO3(-) did not exert significant influence on MB degradation but humic acid decreased the MB degradation rate. As a regenerable adsorbent, negligible difference in regeneration efficiency was observed when a higher Oxone(®) dosage was employed but a better efficiency was obtained at a lower MACC loading. The factors hindering complete MACC regeneration are MB adsorption irreversibility and AC surface modification by PMS making it less favorable for subsequent MB adsorption. With an additional mild heat treatment (150 °C) after regeneration, 82% of the active sites were successfully regenerated. A kinetic model incorporating simultaneous first-order desorption, second-order adsorption and pseudo-first order degradation processes was numerically-solved to describe the rate of regeneration. The regeneration rate increased linearly with increasing Oxone(®):MACC ratio. The MACC could potentially serve as a catalyst for PMS activation and regenerable adsorbent. PMID:25463211

  4. Synthesis, structural and mechanical characterization of sputtered tungsten oxide coatings

    OpenAIRE

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

    2006-01-01

    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 (

  5. Thermal and sputtered aluminum oxide coatings for high temperature electrical insulation

    Science.gov (United States)

    Kreider, K. G.; Semancik, S.

    1985-01-01

    Aluminum oxide coatings have been investigated as electrically insulating layers for mounting thin film Pt-Pt/Rh thermocouples on gas turbine blade and vane alloys (MAR M200 + Hf and MAR M509). Thermal oxides were grown directly onto NiCoCrAlY and FeCrAlY coatings on these alloys at temperature between 1300 and 1400 K in oxygen partial pressures 10 to the -7th to 2 x 10 to the 4th Pa. Although these thermal oxides exhibited good adherence, analytical characterizations using electron and optical microscopy, as well as X-ray photoelectron spectroscopy showed that they had defects and impurities which limited their insulating ability. The insulating quality of the coating was greatly improved however by reactively sputtering an aluminum oxide film over the thermal oxide. Results are presented on the electrical performance of the 2-5 micron thick composite layers for temperatures up to 1300 K.

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

    Science.gov (United States)

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

    2012-08-30

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

  7. Removal of metal ions from water solutions by iron/cobalt oxide coated keramzite.

    Science.gov (United States)

    Stefanova, R Y

    2001-01-01

    A method for coating hydrated iron, cobalt and iron/cobalt oxide on the surface of keramzite sand was developed. The coating parameters (pH, amount of coated metal, molar ratio Co/Fe, temperature of modification and time of treatment) controlling sorption ability of the coated layer were determined. The iron/cobalt coated keramzite thermally activated at 450 degrees C obtained at a molar ratio Co/Fe-0.516 is characterized and use for the removal of metal ions. The effect of contact time, solution pH, sorbate concentration, ionic strength and competing metal concentration on the sorption of copper, lead, zinc and cadmium was studied in batch experiments. The results reveal that the sorption rate of metal ions increases more rapidly in the initial period and reach metastable equilibrium within three hours. The sorption on coated keramzite follows both Langmuir and Freundlich's models. The data on the effect of pH showed that the sorption of all metal ions studied was markedly influenced by the solution pH. According to the concept of surface complexation model the experimental results support the assumption that metal adsorption at oxide coated keramzite sand could be better modeled as an innersphere surface reaction. The modified sorbent has a high selectivity towards copper and lead ions. The coated keramzite sand can be recommended as an efficient adsorbent for advanced water treatment of metal-bearing solutions and industrial wastewaters. PMID:11545353

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

    Energy Technology Data Exchange (ETDEWEB)

    Reddy Channu, V.S., E-mail: chinares02@gmail.com [Texas Biochemicals, Inc, College Station, TX 77840 (United States); Ravichandran, D. [Texas Biochemicals, Inc, College Station, TX 77840 (United States); Rambabu, B. [Solid State Ionics and Surface Sciences Lab, Department of Physics, Southern University and A and M College, Baton Rouge, LA 70813 (United States); Holze, Rudolf [Institut für Chemie, AG Elektrochemie, Technische Universität Chemnitz, Chemnitz D-09107 (Germany)

    2014-06-01

    Carbon- and graphene oxide-coated vanadium oxide nanomaterials were synthesized from a VOSO{sub 4} 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.

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

    International Nuclear Information System (INIS)

    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.

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

    International Nuclear Information System (INIS)

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

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

    Science.gov (United States)

    Mcdonald, G. E. (inventor)

    1983-01-01

    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.

  12. Oxide coatings on flexible substrates for electrochromic applications

    Science.gov (United States)

    Aleksandrova, M.

    2014-11-01

    One of the most studied classes of materials in the modern microelectronic devices are the metal oxides. There are different metal oxide films, such as electrodes, charge injecting and electrochromic coatings for displays or "smart" windows applications. This paper aims to describe the recent achievements for oxide coating deposition for flexible electrochromic displays. Although many deposition methods for production of such films have been developed, some of the achievements in the field of RF sputtering of transparent electrodes from indium-tin oxide on low-cost polyethyleneterephthalate substrate are presented. Attention is paid on some critical issues, such as films electro-optical parameters (sheet resistance, transparency in the visible range), adhesion, degradation due to stress and patterning ability.

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

    International Nuclear Information System (INIS)

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

  14. 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.

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

    Directory of Open Access Journals (Sweden)

    Marek DZIENIEWICZ

    2009-01-01

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

  16. Carboxyl-functionalized mesoporous silica–carbon composites as highly efficient adsorbents in liquid phase

    OpenAIRE

    Valle Vigón, Patricia; Sevilla Solís, Marta; Fuertes Arias, Antonio Benito

    2013-01-01

    [EN] Mesoporous silica–carbon composites functionalized with acidic oxygen groups were prepared by oxidation of a layer of carbon deposited inside the silica pores. The synthesis procedure involved the following steps: (a) removal of the silica surfactant, (b) impregnation of the silica pores with a carbon precursor, (c) carbonization and (d) oxidation with ammonium persulfate. The resulting silica–carbon composites contained around 25–30 wt.% of carbonaceous matter with a high density ...

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

    Science.gov (United States)

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

    2007-06-01

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

  18. Adsorbent compositions for the removal of hydrogen sulfide from fluid streams

    International Nuclear Information System (INIS)

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

  19. 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 tregenerated by the CO2 plasma treatment of PET.

  20. Novel transparent conducting sol-gel oxide coatings

    International Nuclear Information System (INIS)

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

  1. Adsorption of Th4+, U6+, Cd2+, and Ni2+ from aqueous solution by a novel modified polyacrylonitrile composite nanofiber adsorbent prepared by electrospinning

    International Nuclear Information System (INIS)

    In this study, SiO2 nanoparticles were modified by 3-aminopropyltriethoxysilane (APTES) and then applied to prepare a novel polyacrylonitrile (PAN) composite nanofiber adsorbent by the electrospinning method. In addition, the adsorbent was characterized by SEM, BET, and FTIR analyses. Then the effects of pH, SiO2 and APTES content, adsorbent dosage, contact time and temperature were investigated. Moreover, adsorption experiments were carried out with initial concentrations in the range of 30–500 mg L?1 and the adsorbent affinity for metal ions was in order of Th4+ > U6+ > Cd2+ > Ni2+. Furthermore, it was observed that the optimum pH for adsorption was different for each metal. Some isotherm and kinetic models were applied to analyze the experimental data, among which the Langmuir and pseudo-second order models were better than the others. The regeneration study showed that the adsorbent could be used for industrial processes repeatedly without any significant reduction in its adsorption capacity. Based on the Langmuir model, the maximum adsorption capacity of Th4+, U6+, Cd2+, and Ni2+ at 45 °C was 249.4, 193.1, 69.5 and 138.7 mg g?1, respectively. Besides, the calculated thermodynamic parameters showed an endothermic as well as chemical nature through the adsorption process

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

    Directory of Open Access Journals (Sweden)

    Qingqing Wang

    2014-03-01

    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.

  3. Hierarchical MWCNTs/Fe3O4/PANI magnetic composite as adsorbent for methyl orange removal.

    Science.gov (United States)

    Zhao, Ying; Chen, Hongli; Li, Jie; Chen, Changlun

    2015-07-15

    Multi-wall carbon nanotubes (MWCNTs) decorated with Fe3O4 nanoparticles (MWCNTs/Fe3O4) were modified by polyaniline (PANI). The adsorption kinetics of methyl orange (MO) on MWCNTs/Fe3O4/PANI could be fitted well by the pseudo-second-order model. The adsorption of MO on MWCNTs/Fe3O4/PANI was strongly dependent on pH values. The Langmuir isotherm model fitted MO adsorption isotherm better than the Freundlich model. The hierarchical MWCNTs/Fe3O4/PANI showed high adsorption capacity toward ionic dyes (446.25mgg(-1) for MO and 417.38mgg(-1) for Congo red (CR)). The nitrogen-containing functional groups of PANI decorated on MWCNTs/Fe3O4/PANI contributed to many effective adsorption sites and thus increased the adsorption capacity toward MO and CR. Moreover, PANI prevented Fe3O4 nanoparticles from dissolution, and hence improved the stability of MWCNTs/Fe3O4/PANI in solution. The experimental results showed that the MWCNTs/Fe3O4/PANI composite was a promising magnetic material for the preconcentration and separation of ionic dye pollutants from aqueous solutions in environmental pollution cleanup. PMID:25819003

  4. Characterization of carbonated tricalcium silicate and its sorption capacity for heavy metals: a micron-scale composite adsorbent of active silicate gel and calcite.

    Science.gov (United States)

    Chen, Quanyuan; Hills, Colin D; Yuan, Menghong; Liu, Huanhuan; Tyrer, Mark

    2008-05-01

    Adsorption-based processes are widely used in the treatment of dilute metal-bearing wastewaters. The development of versatile, low-cost adsorbents is the subject of continuing interest. This paper examines the preparation, characterization and performance of a micro-scale composite adsorbent composed of silica gel (15.9 w/w%), calcium silicate hydrate gel (8.2 w/w%) and calcite (75.9 w/w%), produced by the accelerated carbonation of tricalcium silicate (C(3)S, Ca(3)SiO(5)). The Ca/Si ratio of calcium silicate hydrate gel (C-S-H) was determined at 0.12 (DTA/TG), 0.17 ((29)Si solid-state MAS/NMR) and 0.18 (SEM/EDS). The metals-retention capacity for selected Cu(II), Pb(II), Zn(II) and Cr(III) was determined by batch and column sorption experiments utilizing nitrate solutions. The effects of metal ion concentration, pH and contact time on binding ability was investigated by kinetic and equilibrium adsorption isotherm studies. The adsorption capacity for Pb(II), Cr(III), Zn(II) and Cu(II) was found to be 94.4 mg/g, 83.0 mg/g, 52.1 mg/g and 31.4 mg/g, respectively. It is concluded that the composite adsorbent has considerable potential for the treatment of industrial wastewater containing heavy metals. PMID:17950999

  5. 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.)

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

    OpenAIRE

    VLADIMIR V. PANIC; BRANISLAV Z. NIKOLIC

    2007-01-01

    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 micro...

  7. 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.

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

    Energy Technology Data Exchange (ETDEWEB)

    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

    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.

  9. Negative pressures and melting point depression in oxide-coated liquid metal droplets

    Science.gov (United States)

    Spaepen, F.; Turnbull, D.

    1979-01-01

    Negative pressures and melting point depression in oxide-coated liquid metal droplets are studied. The calculation presented show the existence of large negative pressures when the oxide coating is thick enough. The change in the melting point caused by these negative pressures should be considered in studies of homogeneous crystal nucleation. Furthermore, since the negative pressure raises the entropy of the melt, it increases the entropy loss at the crystal-melt interface; the resulting increase of the surface tension could have a large effect on the homogeneous nucleation frequency.

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

    International Nuclear Information System (INIS)

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

  11. 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)

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

    1996-01-01

    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.

  12. 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

  13. Formulation of an alginate-vineyard pruning waste composite as a new eco-friendly adsorbent to remove micronutrients from agroindustrial effluents.

    Science.gov (United States)

    Vecino, X; Devesa-Rey, R; Moldes, A B; Cruz, J M

    2014-09-01

    The cellulosic fraction of vineyard pruning waste (free of hemicellulosic sugars) was entrapped in calcium alginate beads and evaluated as an eco-friendly adsorbent for the removal of different nutrients and micronutrients (Mg, P, Zn, K, N-NH4, SO4, TN, TC and PO4) from an agroindustrial effluent (winery wastewater). Batch adsorption studies were performed by varying the amounts of cellulosic adsorbent (0.5-2%), sodium alginate (1-5%) and calcium chloride (0.05-0.9M) included in the biocomposite. The optimal formulation of the adsorbent composite varied depending on the target contaminant. Thus, for the adsorption of cationic contaminants (Mg, Zn, K, N-NH4 and TN), the best mixture comprised 5% sodium alginate, 0.05M calcium chloride and 0.5% cellulosic vineyard pruning waste, whereas for removal of anionic compounds (P, SO4 and PO4), the optimal mixture comprised 1% sodium alginate, 0.9M calcium chloride and 0.5% cellulosic vineyard pruning waste. To remove TC from the winery wastewater, the optimal mixture comprised 3% of sodium alginate, 0.475M calcium chloride and 0.5% cellulosic vineyard pruning waste. PMID:24997896

  14. Insulating characteristics and hydrogen absorption of aluminum oxide coatings deposited by RF magnetron sputtering

    International Nuclear Information System (INIS)

    Aluminum oxide with high resistivity and tritium permeation resistance is considered as a promising candidate functional material for ITER. In this study, aluminum oxide coatings were prepared onto the China Low Activation Martensitic (CLAM) steel substrates via RF magnetron sputtering. The structure and the surface morphologies of the coatings prepared at various O2/Ar ratios were characterized via grazing incidence Xray diffraction, Raman spectroscopy and atomic force microscopy. The Janume resistivities of the coatings were measured. The hydrogen absorption of the coating samples was also studied. The results show that the aluminum oxide coatings prepared at O2/Ar ratios of 0.1 and 0.5 are amorphous, while the aluminum oxide coating prepared at an O2/Ar ratio of 0.4 h as a poor ? phase crystalline structure. The roughness average and the particle size of the coatings prepared at O2/Ar ratios of 0.1 and 0.4 are smaller than those prepared at an O2/Ar ratio of 0.5. The Janume resistivities of the coatings prepared at various O2/Ar ratios all exceed 2.7 x 1014 ?·cm, and the coating prepared at an O2/Ar ratio of 0.4 h as the largest resistivity, reaching 2.1 x 1015 ?·cm. The hydrogen absorption of the coating prepared at an O2/Ar ratio of 0.5 is the smallest. The electrical insulation and hydrogen absorption properties of the aluminum oxide coatings are afof the aluminum oxide coatings are affected significantly by O2/Ar ratios. (authors)

  15. 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)

    Velmurugan Thavasi

    2009-01-01

    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.

  16. Rusty nails adsorb trace plutonium from the environment

    International Nuclear Information System (INIS)

    Discarded rusty iron objects in the environment adsorb trace plutonium mobilized by oxygenated surface waters (e.g. rain, snow melt). Radiochemical and mass spectrometric analysis of the surface oxide coating of modest collections of rusty nails retrieved from remote locations provides a global fallout plutonium signal of up to 2 x 1010 atoms of 239Pu per sample. The median 239Pu measurement for 10 samples from five locations was 2.82 x 109 atoms. The average 240Pu/239Pu atom ratio was 0.176 ± 0.012, consistent with the value accepted for global fallout. (author)

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

    International Nuclear Information System (INIS)

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

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

    International Nuclear Information System (INIS)

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

  19. A Comparative Study of Natural Fiber and Glass Fiber Fabrics Properties with Metal or Oxide Coatings

    Science.gov (United States)

    Lusis, Andrej; Pentjuss, Evalds; Bajars, Gunars; Sidorovicha, Uljana; Strazds, Guntis

    2015-03-01

    Rapidly growing global demand for technical textiles industries is stimulated to develop new materials based on hybrid materials (yarns, fabrics) made from natural and glass fibres. The influence of moisture on the electrical properties of metal and metal oxide coated bast (flax, hemp) fibre and glass fibre fabrics are studied by electrical impedance spectroscopy and thermogravimetry. The bast fibre and glass fiber fabrics are characterized with electrical sheet resistance. The method for description of electrical sheet resistance of the metal and metal oxide coated technical textile is discussed. The method can be used by designers to estimate the influence of moisture on technical data of new metal coated hybrid technical textile materials and products.

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

    International Nuclear Information System (INIS)

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

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

    International Nuclear Information System (INIS)

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

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

    OpenAIRE

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

    2008-01-01

    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...

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

    OpenAIRE

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

    2012-01-01

    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...

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

    Directory of Open Access Journals (Sweden)

    Stela Maria de Carvalho Fernandes

    2004-03-01

    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.

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

    Scientific Electronic Library Online (English)

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

    2004-03-01

    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.

  6. 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

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

    Science.gov (United States)

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

    2013-09-01

    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.

  8. Cavitation erosion resistance of microarc oxidation coating on aluminium alloy

    International Nuclear Information System (INIS)

    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.

  9. 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)

  10. Biogas from MSW landfill: Composition and determination of chlorine content with the AOX (adsorbable organically bound halogens) technique

    International Nuclear Information System (INIS)

    An exhaustive characterization of the biogas from some waste disposal facilities has been carried out. The analysis includes the main components (methane, carbon dioxide, nitrogen and oxygen) as well as trace components such as hydrogen sulphide, ammonia and VOCs (volatile organic compounds) including siloxanes and halogenated compounds. VOCs were measured by GC/MS (Gas Chromatography/Mass Spectrometry) using two different procedures: thermal desorption of the Tenax TA and Carbotrap 349 tubes and SPME (Solid Phase Micro-Extraction). A method has been established to measure the total halogen content of the biogas with the AOX (adsorbable organically bound halogens) technique. The equipment used to analyze the samples was a Total Organic Halogen Analyzer (TOX-100). Similar results were obtained when comparing the TOX (Total Organic Halogen) values with those obtained by GC/MS. The halogen content in all the samples was under 22 mg Cl/Nm3 which is below the limit of 150 mg/Nm3 proposed in the Spanish Regulations for any use of the biogas. The low chlorine content in the biogas studied, as well as the low content of other trace compounds, makes it suitable for use as a fuel for electricity generating engines

  11. Origin of complex impact craters on native oxide coated silicon surfaces

    International Nuclear Information System (INIS)

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

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

    Directory of Open Access Journals (Sweden)

    Q. Fu

    2012-04-01

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

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

    Directory of Open Access Journals (Sweden)

    Lanza Marcos Roberto V.

    2002-01-01

    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.

  14. Voltage oxide removal for plating: A new method of electroplating oxide coated metals in situ

    International Nuclear Information System (INIS)

    A novel in situ method for electroplating oxide coated metals is described. Termed VORP, for voltage oxide removal for plating, the process utilizes a voltage pulse ?20-200 V, ?2 ms in duration, applied between working and counterelectrodes while both are immersed in a copper electrolyte. The pulse is almost immediately followed by galvanostatic plate-up. Adherent copper deposits up to ?4 ?m in height on stainless steel 316 coupons have been obtained. Temperature testing up to 260 deg. C in air does not affect the copper adhesion. A preliminary model for oxide removal is proposed utilizing concepts of dielectric breakdown

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

    International Nuclear Information System (INIS)

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

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

    Directory of Open Access Journals (Sweden)

    VLADIMIR V. PANIC

    2007-12-01

    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.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2014-07-15

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

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

    DEFF Research Database (Denmark)

    MØller, J.; Ledin, Anna

    2002-01-01

    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.

  19. Long-term corrosion inhibition mechanism of microarc oxidation coated AZ31 Mg alloys for biomedical applications

    International Nuclear Information System (INIS)

    Highlights: ? The corrosion behavior is significantly affected by the long-term immersion. ? The degradation is inhibited due to the corrosion product layer. ? The corrosion resistance is enhanced by optimized MAO electrolyte concentrations. ? The corrosion inhibition mechanism is presented by a Flash animation. - Abstract: This paper addresses the long-term corrosion behavior of microarc oxidation coated Mg alloys immersed in simulated body fluid for 28 days. The coatings on AZ31 Mg alloys were produced in the electrolyte of sodium phosphate (Na3PO4) at the concentration of 20 g/L, 30 g/L and 40 g/L, respectively. Scanning electron microscope (SEM) and optical micrograph were used to observe the microstructure of the samples before and after corrosion. The composition of the MAO coating and corrosion products were determined by X-Ray Diffraction (XRD). Corrosion product identification showed that hydroxyapatite (HA) was formed on the surface of the corroded samples. The ratio of Ca/P in HA determined by the X-ray Fluorescence (XRF) technique showed that HA is an acceptable biocompatible implant material. The potentiodynamic polarization and electrochemical impedance spectroscopy (EIS) were employed to characterize the corrosion rate and the electrochemical impedance. The corrosion resistance of the coated Mg alloys can be enhanced by optimizing the electrolyte concentrations for fabricating samples, and is enhanced after immersing the coated samples in simulated body fluid for more than 14 days. The enhanced corrosion resistance after long-term immersion is attributed to a corrosion product layer formed on the sample surface. The inhibition mechanism of the corrosion process is discussed and presented with an animation

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

    International Nuclear Information System (INIS)

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

  1. 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.ce of humic acid.

  2. 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...

  3. On the application of acoustic emission analysis to evaluate the integrity of protective oxide coatings

    International Nuclear Information System (INIS)

    Protective coatings extend the range of applications for materials. Surface properties can be selectively adapted for each problem. Thus bare high-temperature alloys for heat exchanging units e.g. in high-temperature systems for producing substitute natural gas do not have sufficient protection against undesirable tritium permeation from the helium primary gas into the substitute natural gas generated. A chromium oxid coating, on the other hand, of only a few ?m in thickness ensures a barrier effect combines with an inhibitive factor H = 1000. Good adhesion is required for a successful application, in the same way as good temperature cycling resistance under start-up and shut-down conditions is of decisive significance for every type of coating

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

    CERN Document Server

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

    2002-01-01

    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.

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

    International Nuclear Information System (INIS)

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

  6. 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

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

    Directory of Open Access Journals (Sweden)

    Nie Yining

    2010-09-01

    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.

  8. Is ash layer of ~ 8 Ma at ODP-758 from Bay of Bengal and Fe-Mn oxide coated pumice from Central Indian Ocean Basin are from same eruption ?

    Science.gov (United States)

    Pattan, J. N.; Jumaila, C.; Ahmad, S. M.; Khedekar, V.; Parthiban, G.; Padmakumari, V.

    2013-12-01

    An ash layer of ~8 Ma old is recovered from the Bay of Bengal ODP 758 site. Glass shards from this ash layer have been studied for their morphology and chemical composition to trace its source. Earlier, in the Central Indian Ocean Basin occurrence of uncoated and Fe-Mn oxide coated pumice which are of younger (few thousand years) and older (few Ma) in age were reported. Glass grains were separated from the Fe-Mn oxide coated pumice and a studied for morphology and chemical composition. In the present study, an attempt has been made to compare both ash layer and glass from the pumice to trace their source and relation between them if any. Glass shards from the ash layer exhibit bubble wall type morphology and presence of pumice shards while, glass from pumice have pumice shards, suggesting magmatic type of eruption. Electron Probe Micro Analysis of glass shards and glass shows has high content of SiO2 (79%) and total alkalies (6%) indicating rhyolite nature and rich in K- cal-alkaline series. Potassium content in pumice is relatively low as compared to glass shards probably suggest leaching of K by the sea water interaction. Other major oxide contents (Al2O3, TiO2, FeO, MnO and MgO) are nearly similar in both shard and pumice glass. Total rare earth element (?REE) of glass shard (147 ppm) and glass (158 ppm) are nearly same, enriched in light REE, with a pronounced negative Eu-anomaly and exhibit flat heavy REE distribution. Tectnomagmatic and triangular plots suggest that both glass shards and glass are of arc type origin. The nearest Indonesian Arc is most probably acting as the source for both of them. Pumice in the present study has 3-4 mm thick Fe-Mn oxide coatings. In Central Indian Ocean Basin earlier report suggested that Fe-Mn oxide accumulates at ~ 2 mm/Ma. This indicates that pumice are of ~6-8 Ma old which is nearly similar in age (~8 Ma) of ash layer encountered at ODP site 758. Therefore, the present study suggest that ash layer of ~ 8 Ma old and Fe-Mn oxide coated pumice may probably correspond to a single eruption from Indonesian Arc Volcanism. However, precise dating of these pumice needs to be carried out for further confirmation.

  9. Influence of mechanical abrasion of carbon adsorbents on aerodynamic resistance of filters of system of ventilation of NPS

    International Nuclear Information System (INIS)

    Influence of mechanical abrasion of granules on aerodynamic resistance of different carbon adsorbents at conditions similar to work of filters AU-1500 is studied. The change of fractional composition of the probed adsorbents by abrasion is determined. The obtained experimental data allow making conclusion about practicability using mixture of adsorbent Norit with different fractional composition for renewal of adsorbers of ventilation system of NPS.

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

    OpenAIRE

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

    2006-01-01

    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,...

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

    OpenAIRE

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

    2005-01-01

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

  12. 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

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2000-12-01

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

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2014-03-15

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

  15. Corrosion properties of steel protected by nanometre-thick oxide coatings

    International Nuclear Information System (INIS)

    Highlights: • 40–50 nm mixed alumina–tantala coatings were grown by atomic layer deposition. • Effects of substrate surface finish and oxide mix were analysed. • Nanolaminate stacks are better resistant to breakdown. • Localised corrosion occurs at pre-existing coating defects exposing substrate sites. • Substrate brushing and H2–Ar plasma pre-treatment hinder pit initiation. - Abstract: A comprehensive study of the corrosion properties of low alloy steel protected by 40–50 nm aluminium and tantalum mixed oxide coatings grown by atomic layer deposition is reported. Electrochemical and surface analysis was performed to address the effect of substrate surface finish and whether an oxide mixture or nanolaminate was used. There was no dissolution or breakdown for nanolaminate alumina/tantala stacks in acidic NaCl solution. Localised corrosion (pitting) took place when defects exposing the substrate pre-existed in the coating. Substrate pre-treatment by brushing and H2–Ar plasma was instrumental to block or slow down pit initiation by reducing the defect dimensions

  16. Fabrication of density-controlled graphene oxide-coated mesoporous silica spheres and their electrorheological activity.

    Science.gov (United States)

    Yoon, Chang-Min; Lee, Seungae; Hong, Seung Hee; Jang, Jyongsik

    2015-01-15

    A series of density-controlled graphene oxide-coated mesoporous silica spheres (GO/SiO2) are successfully synthesized to investigate the influence of the particle density on electrorheological (ER) activity. The particle density of mesoporous silica spheres is controlled by creating different sized pores via surfactant template and swelling agent incorporation method. Additionally, ball-milled graphene oxide is successfully coated onto the surface of various silica spheres (SiO2) through amine-modification to enhance ER efficiency. In this study, we investigate that mesoporous silica spheres-based ER fluid (GO/epSiO2) with lowest particle density exhibit most increased ER performance, which is 3-fold higher than that of similar sized neat silica spheres-based ER fluid (GO/nSiO2) without pore. In addition, the relationship between particle density, anti-sedimentation property, and ER performance is examined by applying Stokes' law and practical sedimentation observation. Furthermore, dielectric loss model is used to clarify the influence of dielectric property on ER activity. This newly designed ER study offers insight into the influence of the particle density on the performance of ER fluids. PMID:25454420

  17. One-step breaking and separating emulsion by tungsten oxide coated mesh.

    Science.gov (United States)

    Lin, Xin; Lu, Fei; Chen, Yuning; Liu, Na; Cao, Yingze; Xu, Liangxin; Wei, Yen; Feng, Lin

    2015-04-22

    Tungsten oxide coated mesh has been fabricated by a simple and inexpensive method. This coated mesh has a dual structure on the surface, consisting of microscale "flower" and nanoscale acicular crystal as the "petal". Combining the micro/nano structure of the surface and the native hydrophilic property of tungsten oxide, the coated mesh shows special wettability: superhydrophilic in air and superoleophobic under water. Because of the special wettability, such a mesh can be used to separate oil/water mixtures as well as emulsions. Attributed to the good water adsorption capacity of tungsten oxide, the abundant grooves of the micro/nanostructure, and the microsized pores of the surface, this coated mesh can accomplish the demulsification process and the separation process in one single-step, and no further post treatment is needed. As an "emulsion breaker and separator", this kind of mesh gives another idea of emulsion separation, which has prospective application in industrial fields such as water treatment and petroleum refining. PMID:25757033

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

    International Nuclear Information System (INIS)

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

  19. Titanium-nitride-oxide-coated Titan-2 bioactive coronary stent: a new breakthrough in interventional cardiology.

    Science.gov (United States)

    Karjalainen, P; Nammas, W

    2011-10-01

    The introduction of drug-eluting stents (DES) has revolutionized the field of interventional cardiology, since it has reduced the incidence of restenosis by 50% to 70%. However, recent worrisome data from registries and meta-analyses emphasized higher rates of late and very late stent thrombosis associated with DES. The recently introduced titanium-nitride-oxide-coated stent bioactive stent (Titan-2) was manufactured by a proprietary process to coat titanium-nitride-oxide on the surface of the stainless steel stent, based on a plasma technology using the nano-synthesis of gas and metal. This late-breaking stent has demonstrated an excellent biocompatibility, as reflected by lower rates of platelet aggregation and fibrin deposition, and better endothelialization. Preclinical and clinical trials and registries involving real-life unselected populations have shown a low rate of major adverse cardiac events at long-term follow-up. Restenosis rates were comparable with those of DES, with very rare stent thrombosis. Equally favorable results have been obtained in patients at high-risk of in-stent restenosis, such as diabetics and those with small coronary arteries. Results in patients presenting with acute coronary syndrome have been again comparable to those of DES, with tendency to lower rates of myocardial infarction and stent thrombosis. Comparisons with second generation drug-eluting stents have also been promising. PMID:21983305

  20. Novel concept of functional oxide coatings providing enhanced oxidation resistance to Ni-based superalloys

    International Nuclear Information System (INIS)

    Graphical abstract: - Highlights: • New concept for providing extended oxidation resistance to Ni-based superalloys. • Oxygen-defective nanostructured oxide coatings reduce the oxygen partial pressure at the substrate interface. • Pre-oxidation of the substrate during annealing with the formation of alpha-alumina. • Growth of CeAlO3 perovskite enhancing the adherence of the ceria top coat. • Microstructural stability of the coating system with no SRZ formation upon exposure. - Abstract: Aluminide-coated Ni-based superalloys are prone to microstructural instabilities during long-term exposure at high temperature with the growth of a secondary reaction zone (SRZ) detrimental from a mechanical viewpoint. This has been since overcome by the use of thermodynamically stable coatings (?-Ni/??-Ni3Al). However, additions of Pt and Hf are required to provide the formation of an exclusive ?-Al2O3 scale and improved oxidation resistance in cyclic and isothermal regimes. The present work proposes a new coating system that relies on the use of a superficial nanostructured functional oxide providing the establishment of a stable alumina while avoiding SRZ formation. Tailored oxygen-defective and multi-cracked coatings were designed for 2nd generation Ni-based superalloys and generated by electrosynthesis using a water-based solution. Cyclic oxidation tests were carried out at 1100 °Cural stability of the coating system were demonstrated

  1. Performance comparison of dye-sensitized solar cells by using different metal oxide- coated TiO2 as the photoanode

    Directory of Open Access Journals (Sweden)

    Sun Xuhui

    2014-01-01

    Full Text Available In order to increase the conversion efficiency of dye-sensitized solar cells, TiO2 photoanode surface is often covered with a metal oxide layer to form a core-shell composite structure. Different metal oxide coating on TiO2 as composite photoanodes can affect the cell efficiency variously. However, there still lacks the crosswise comparison among the effects of different metal oxides on TiO2 photoanode. In this study, TiO2 was coated with Al2O3, CaO, ZnO, MgO, Fe2O3 or Bi2O3 separately by liquid phase deposition method. The results indicated that cells with TiO2/Al2O3, TiO2/ZnO, TiO2/CaO, or TiO2/MgO composite film as a photoanode had higher conversion efficiency than those with un-coated TiO2 films. TiO2/Al2O3 showed the highest efficiency and TiO2/CaO ranked second. On the contrary, cells with TiO2/Bi2O3 or TiO2/Fe2O3 composite film as a photoanode had lower conversion efficiency than those with un-coated TiO2 films. The mechanism of the cell efficiency change was also investigated. To get higher conversion efficiency, matched energy level of the metal oxide with TiO2 is the first prerequisite, and then the optimum coating thickness is also a necessary condition.

  2. Reduced bleaching in organic nanofibers by bilayer polymer/oxide coating

    DEFF Research Database (Denmark)

    Tavares, Luciana; Kjelstrup-Hansen, Jakob

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

  3. Electrochemical oxidation of 2,4,5-trichlorophenoxyacetic acid by metal-oxide-coated Ti electrodes.

    Science.gov (United States)

    Maharana, Dusmant; Xu, Zesheng; Niu, Junfeng; Rao, Neti Nageswara

    2015-10-01

    Electrochemical oxidation of 2,4,5-trichlorophenoxyacetic acid (2,4,5-T) over metal-oxide-coated Ti anodes, i.e., Ti/SnO2-Sb/Ce-PbO2, Ti/SnO2-Sb and Ti/RuO2, was examined. The degradation efficiency of over 90% was attained at 20min at different initial concentrations (0.5-20mgL(-1)) and initial pH values (3.1-11.2). The degradation efficiencies of 2,4,5-T on Ti/SnO2-Sb/Ce-PbO2, Ti/SnO2-Sb and Ti/RuO2 anodes were higher than 99.9%, 97.2% and 91.5% at 30min, respectively, and the respective total organic carbon removal ratios were 65.7%, 54.6% and 37.2%. The electrochemical degradation of 2,4,5-T in aqueous solution followed pseudo-first-order kinetics. The compounds, i.e., 2,5-dichlorohydroquinone and 2,5-dihydroxy-p-benzoquinone, have been identified as the main aromatic intermediates by liquid chromatography-mass spectrometry. The results showed that the energy efficiencies of 2,4,5-T (20mgL(-1)) degradation with Ti/SnO2-Sb/Ce-PbO2 anode at the optimal current densities from 2 to 16mAcm(-2) ranged from 8.21 to 18.73kWhm(-3). PMID:25981800

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

    Directory of Open Access Journals (Sweden)

    Moch Adnan2

    2005-04-01

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

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

    International Nuclear Information System (INIS)

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

  6. Removal of arsenic from contaminated water sources by sorption onto iron-oxide-coated polymeric materials

    OpenAIRE

    Katsoyiannis, I.A.; ????????????, ?.?.; Zouboulis, a.I.; ??????????, ?.?

    2009-01-01

    The modification of polymeric materials (polystyrene and polyHIPE) by coating their surface with appropriate adsorbing agents (i.e. iron hydroxides) was investigated in the present work, in order to apply the modified media in the removal of inorganic arsenic anions from contaminated water sources. The method, termed adsorptive filtration, has been classified as an emerging technology in water treatment processes as it presents several advantages towards conventional technologies: the product...

  7. 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)

    Yi Liu

    2013-05-01

    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.

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

    International Nuclear Information System (INIS)

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

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

    Science.gov (United States)

    Yang, Xinyao; Liang, Dongxu; Deng, Shihuai

    2012-09-01

    Ethylenediaminotetraacetic acid (EDTA) occurring in groundwater aquifers complicates the prediction of nanoparticle movement in the porous medium. This paper demonstrates an approach combining Triple Pulse Experiments (TPEs) and numerical modelling to quantify the influence of EDTA on the deposition and retention of polymer nanoparticles in a water-saturated column packed with iron-oxide-coated sand. TPEs injecting three successive pulses in the order of nanoparticle, EDTA, nanoparticle permit nanoparticle deposition in the absence and the presence of EDTA to be compared. Random Sequential Adsorption (RSA) modelling of the nanoparticle breakthrough curves combining mass balance calculation allows the influence of EDTA to be quantified. TPE results demonstrate that the injected EDTA eluted the oxide coatings (favorable deposition sites) from the sand surface and the resulting decline in sites led to enhanced nanoparticle mobility in the subsequent pulse. Quantification results suggest that at the experimental time-scale and under the controlled conditions, elution of one deposition site requires injection of 2.4 × 10(11) EDTA molecules. In total, 75 gram EDTA needs to be injected to remove all the column sites. PMID:22797714

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2010-12-15

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

  11. 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 m3/d) is reported, and the feasibility of uranium extraction from seawater by this process is demonstrated. 10 figures

  12. Magnetic composite of Fe3O4 and activated carbon as a adsorbent for separation of trace Sr(II) from radioactive wastewater

    International Nuclear Information System (INIS)

    Magnetic adsorbent of Fe3O4 and activated carbon (Fe3O4/AC) was prepared by chemical coprecipitation technique, and was characterized by SEM, TEM, BET, XRD, and VSM techniques in details. The adsorption results of Sr(II) on Fe3O4/AC revealed that Sr(II) adsorption on Fe3O4/AC surface was an spontaneous and endothermic process, and can be well described by the pseudo-second-order model. The adsorption of Sr(II) on Fe3O4/AC increased with increasing pH, and decreased with increasing ionic strength. Fe3O4/AC can be easily separated from aqueous solution with an external magnetic field after application. (author)

  13. 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.

  14. Regenerative adsorbent heat pump

    Science.gov (United States)

    Jones, Jack A. (Inventor)

    1991-01-01

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

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

    Scientific Electronic Library Online (English)

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

    2005-08-01

    Full Text Available 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.

  16. Transporting method for adsorbing tower and the adsorbing tower

    International Nuclear Information System (INIS)

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

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

    Science.gov (United States)

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

    2014-11-01

    After clarifying the formation mechanism of a typical metal glycolate precipitate, Ti glycolate, in a polyol-mediated synthesis using acetone as a precipitation medium, we describe a simple template-free approach based on an ethylene glycol-mediated synthesis to fabricate mesoporous metal oxide coated-nanocarbon hybrid materials including TiO2 coated-carbon nanotube (CNT), SnO2 coated-CNT, Cu2O/CuO coated-CNT and TiO2 coated-graphene sheet (GS). In the approach, metal oxide precursors, metal glycolates, were first deposited on CNTs or GSs, and subsequently transformed to the metal oxide coatings by pyrolysis or hydrolysis. By a comparison between the characterization of two TiO2-CNT hybrid materials using carboxylated CNTs and pristine CNTs without carboxyl groups, the driving force for initiating the deposition of metal glycolates on the carboxylated CNTs is confirmed to be the hydrogen bonding between the carboxyl groups and the polymer chains in metal glycolate sols. The electrochemical performances of the mesoporous TiO2 coated-carboxylated CNTs and TiO2-pristine CNT hybrid materials were investigated. The results show that the mesoporous TiO2 coated-carboxylated CNT with a uniform core-shell nanostructure exhibits substantial improvement in the rate performance in comparison with its counterpart from 0.5 C to 100 C because of its higher electronic conductivity and shorter diffusion path for the lithium ion. At the extremely high rate of 100 C, the specific capacity of TiO2 of the former reaches 85 mA h g-1, twice as high as that of the latter.After clarifying the formation mechanism of a typical metal glycolate precipitate, Ti glycolate, in a polyol-mediated synthesis using acetone as a precipitation medium, we describe a simple template-free approach based on an ethylene glycol-mediated synthesis to fabricate mesoporous metal oxide coated-nanocarbon hybrid materials including TiO2 coated-carbon nanotube (CNT), SnO2 coated-CNT, Cu2O/CuO coated-CNT and TiO2 coated-graphene sheet (GS). In the approach, metal oxide precursors, metal glycolates, were first deposited on CNTs or GSs, and subsequently transformed to the metal oxide coatings by pyrolysis or hydrolysis. By a comparison between the characterization of two TiO2-CNT hybrid materials using carboxylated CNTs and pristine CNTs without carboxyl groups, the driving force for initiating the deposition of metal glycolates on the carboxylated CNTs is confirmed to be the hydrogen bonding between the carboxyl groups and the polymer chains in metal glycolate sols. The electrochemical performances of the mesoporous TiO2 coated-carboxylated CNTs and TiO2-pristine CNT hybrid materials were investigated. The results show that the mesoporous TiO2 coated-carboxylated CNT with a uniform core-shell nanostructure exhibits substantial improvement in the rate performance in comparison with its counterpart from 0.5 C to 100 C because of its higher electronic conductivity and shorter diffusion path for the lithium ion. At the extremely high rate of 100 C, the specific capacity of TiO2 of the former reaches 85 mA h g-1, twice as high as that of the latter. Electronic supplementary information (ESI) available. See DOI: 10.1039/C4NR04254A

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

    Science.gov (United States)

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

    2013-10-01

    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.

  19. Reduced graphene oxide coated polydimethylsiloxane film as an optoacoustic transmitter for high pressure and high frequency ultrasound generation

    Science.gov (United States)

    Lee, Seok Hwan; Lee, Yongseon; Yoh, Jack J.

    2015-02-01

    We demonstrate that reduced graphene oxide coated thin polydimethylsiloxane (rGO-PDMS) film is an effective optoacoustic transmitter for generating high pressure and high frequency ultrasound, previously unattainable using other techniques. Various coatings such as rGO-Aluminum, rGO-PDMS, PDMS-alone, and aluminum-alone are deposited on the glass substrate. Under a pulsed laser excitation, rGO-PDMS transmitter generated remarkable optoacoustic pressure which is 76 times stronger than Al-alone, 5 times stronger than PDMS-alone, and 2.2 times stronger than rGO-Al transmitter. The observed signal enhancement persisted over a broadband frequency range, and thus by optimizing the thermoelasticity of PDMS film and the thermal conductivity of rGO, a promising optoacoustic wave generation was confirmed for laser-induced ultrasound applications.

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

    OpenAIRE

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

    2008-01-01

    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...

  1. Influence of adsorbed polar molecules on the electronic transport in a composite material Li(1.1)V3O8-PMMA for lithium batteries.

    Science.gov (United States)

    Badot, J C; Ligneel, E; Dubrunfaut, O; Gaubicher, J; Guyomard, D; Lestriez, B

    2012-07-14

    The broadband dielectric spectroscopy (BDS) technique (40 to 10(10) Hz) is used here to measure the electronic transport across all observed size scales of a Li(1.1)V(3)O(8)-polymer-gel composite material for lithium batteries. Different electrical relaxations are evidenced, resulting from the polarizations at the different scales of the architecture: (i) atomic lattice (small-polaron hopping), (ii) particles, (iii) clusters of particles, and finally (iv) sample-current collector interface. A very good agreement with dc-conductivity measurements on a single macro-crystal [M. Onoda and I. Amemiya, J. Phys.: Condens. Matter, 2003, 15, 3079.] shows that the BDS technique does allow probing the bulk (intrinsic) electrical properties of a material in the form of a network of particles separated by boundaries in a composite. Moreover, this study highlights a lowering of the surface electronic conductivity of Li(1.1)V(3)O(8) particles upon adsorption of polar ethylene carbonate (EC) and propylene carbonate (PC) that trap surface polarons. This result is meaningful as EC and PC are typical constituents of a liquid electrolyte of lithium batteries. It is thus suggested that interactions between active material particles and the liquid electrolyte play a role in the electronic transport within composite electrodes used in a lithium battery. PMID:22652605

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

    International Nuclear Information System (INIS)

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

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2014-05-07

    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.

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

    International Nuclear Information System (INIS)

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

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2010-06-01

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

  6. 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

  7. Green Adsorbents for Wastewaters: A Critical Review

    Directory of Open Access Journals (Sweden)

    George Z. Kyzas

    2014-01-01

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

  8. High performance Mo adsorbent PZC

    Energy Technology Data Exchange (ETDEWEB)

    Anon.

    1998-10-01

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

  9. Positronium chemistry in porous adsorbents

    International Nuclear Information System (INIS)

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

  10. 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

  11. Introduce, research and testing of type ? adsorber

    International Nuclear Information System (INIS)

    Introduce the theory and function of Type ? Adsorber. Briefly describe the Type ? Adsorber designed by Shanghai Nuclear Engineering and Design Institute, and its testing to prove that the Type ? Adsorber has the advantages comparing with Type ? and ? Adsorbers. Also prove that the Type ? Adsorber designed by Shanghai Nuclear Engineering and Design Institute can be used in AP1000 and other nuclear power plants. (authors)

  12. Enhanced capacitive performance of TiO? nanotubes with molybdenum oxide coating

    Energy Technology Data Exchange (ETDEWEB)

    Guan, Dongsheng; Gao, Xianfeng; Li, Jianyang; Yuan, Chris, E-mail: cyuan@uwm.edu

    2014-05-01

    Highlights: • MoO? was firstly deposited on TiO? nanotubes for better supercapacitive behaviors. • Coated TiO? nanotubes showed much higher capacitance than pure TiO? or MoO? films. • Deposition cycles were optimized to gain the best capacitance of MoO?/TiO? hybrids. - Abstract: Alpha-phase MoO? is electrochemically deposited on well-aligned TiO? nanotubes which are synthesized by anodic oxidation. The morphology, composition and electrochemical behaviors of MoO?-coated and bare TiO? nanotubes are studied. The former deliver greatly higher capacitance than the latter and their performance can be readily optimized by varying MoO? 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 TiO? nanotube array electrode. In addition, the coated TiO? nanotubes show significantly more capacitance than a dense MoO? 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 MoO? with high pseudocapacity and TiO? nanotubes with large surface area allowing efficient MoO? 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.

  13. Enhanced capacitive performance of TiO2 nanotubes with molybdenum oxide coating

    International Nuclear Information System (INIS)

    Highlights: • MoO3 was firstly deposited on TiO2 nanotubes for better supercapacitive behaviors. • Coated TiO2 nanotubes showed much higher capacitance than pure TiO2 or MoO3 films. • Deposition cycles were optimized to gain the best capacitance of MoO3/TiO2 hybrids. - Abstract: 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

  14. 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 latucture 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.)

  15. Magnetic heating properties and neutron activation of tungsten-oxide coated biocompatible FePt core-shell nanoparticles.

    Science.gov (United States)

    Seemann, K M; Luysberg, M; Révay, Z; Kudejova, P; Sanz, B; Cassinelli, N; Loidl, A; Ilicic, K; Multhoff, G; Schmid, T E

    2015-01-10

    Magnetic nanoparticles are highly desirable for biomedical research and treatment of cancer especially when combined with hyperthermia. The efficacy of nanoparticle-based therapies could be improved by generating radioactive nanoparticles with a convenient decay time and which simultaneously have the capability to be used for locally confined heating. The core-shell morphology of such novel nanoparticles presented in this work involves a polysilico-tungstate molecule of the polyoxometalate family as a precursor coating material, which transforms into an amorphous tungsten oxide coating upon annealing of the FePt core-shell nanoparticles. The content of tungsten atoms in the nanoparticle shell is neutron activated using cold neutrons at the Heinz Maier-Leibnitz (FRMII) neutron facility and thereby transformed into the radioisotope W-187. The sizeable natural abundance of 28% for the W-186 precursor isotope, a radiopharmaceutically advantageous gamma-beta ratio of ???30% and a range of approximately 1mm in biological tissue for the 1.3MeV ?-radiation are promising features of the nanoparticles' potential for cancer therapy. Moreover, a high temperature annealing treatment enhances the magnetic moment of nanoparticles in such a way that a magnetic heating effect of several degrees Celsius in liquid suspension - a prerequisite for hyperthermia treatment of cancer - was observed. A rise in temperature of approximately 3°C in aqueous suspension is shown for a moderate nanoparticle concentration of 0.5mg/ml after 15min in an 831kHz high-frequency alternating magnetic field of 250Gauss field strength (25mT). The biocompatibility based on a low cytotoxicity in the non-neutron-activated state in combination with the hydrophilic nature of the tungsten oxide shell makes the coated magnetic FePt nanoparticles ideal candidates for advanced radiopharmaceutical applications. PMID:25445697

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

    International Nuclear Information System (INIS)

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

  17. Instability of waste plumes adsorbed on iron oxide in soils

    International Nuclear Information System (INIS)

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

  18. Adsorbed Water Illustration

    Science.gov (United States)

    2008-01-01

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

  19. Black Sprayable Molecular Adsorber Coating Project

    National Aeronautics and Space Administration — This novel molecular adsorber coating would alleviate the size, weight, and complexity issues of traditional molecular adsorber puck.  A flexible tape version...

  20. New applications of carbonaceous adsorbents

    International Nuclear Information System (INIS)

    Survey of the production, the properties and the definition of the three types of adsorbents activated carbon, activated coke and carbon molecular sieves and their applications in keeping air and water clean and in gas separation processes. (IHOE)

  1. Rotary adsorbers for continuous bulk separations

    Science.gov (United States)

    Baker, Frederick S. (Oak Ridge, TN)

    2011-11-08

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

  2. Magneto-controllable capture and release of cancer cells by using a micropillar device decorated with graphite oxide-coated magnetic nanoparticles.

    Science.gov (United States)

    Yu, Xiaolei; He, Rongxiang; Li, Shasha; Cai, Bo; Zhao, Libo; Liao, Lei; Liu, Wei; Zeng, Qian; Wang, Hao; Guo, Shi-Shang; Zhao, Xing-Zhong

    2013-11-25

    Aiming to highly efficient capture and analysis of circulating tumor cells, a micropillar device decorated with graphite oxide-coated magnetic nanoparticles is developed for magneto-controllable capture and release of cancer cells. Graphite oxide-coated, Fe3 O4 magnetic nanoparticles (MNPs) are synthesized by solution mixing and functionalized with a specific antibody, following by the immobilization of such modified MNPs on our designed micropillar device. For the proof-of-concept study, a HCT116 colorectal cancer cell line is employed to exam the capture efficiency. Under magnetic field manipulation, the high density packing of antibody-modified MNPs on the micropillars increases the local concentration of antibody, as well as the topographic interactions between cancer cells and micropillar surfaces. The flow rate and the micropillar geometry are optimized by studying their effects on capture efficiency. Then, a different number of HCT116 cells spiked in two kinds of cell suspension are investigated, yielding capture efficiency >70% in culture medium and >40% in blood sample, respectively. Moreover, the captured HCT116 cells are able to be released from the micropillars with a saturated efficiency of 92.9% upon the removal of applied magnetic field and it is found that 78% of the released cancer cells are viable, making them suitable for subsequent biological analysis. PMID:23650272

  3. 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)

  4. Carbon nanotubes - the promising adsorbent in wastewater treatment

    Science.gov (United States)

    Li, Y. H.; Zhao, Y. M.; Hu, W. B.; Ahmad, I.; Zhu, Y. Q.; Peng, X. J.; Luan, Z. K.

    2007-03-01

    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.

  5. 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

  6. Nanosize electropositive fibrous adsorbent

    Science.gov (United States)

    Tepper, Frederick; Kaledin, Leonid

    2005-01-04

    Aluminum hydroxide fibers approximately 2 nanometers in diameter and with surface areas ranging from 200 to 650 m.sup.2 /g have been fount to be highly electropositive. When dispersed in water they are able to attach to and retain electronegative particles. When combined into a composite filter with other fibers or particles they can filter bacteria and nano size particulates such as viruses and colloidal particles at high flux through the filter. Such filters can be used for purification and sterilization of water, biological, medical and pharmaceutical fluids, and as a collector/concentrator for detection and assay of mirobes and viruses. The alumina fibers are also capable of filtering sub-micron inorganic and metallic particles to produce ultra pure water. The fibers are suitable as a substrate for growth of cells. Macromolicules such as proteins may be separated from each other based on their electronegative charges.

  7. Pb Isotopes from Paleogene Fe-Mn Oxide Coatings from the Southern Ocean as a Proxy for Deep Water Circulation and Weathering Intensity.

    Science.gov (United States)

    Basak, C.; Martin, E. E.

    2007-12-01

    Pb isotopes extracted from Fe-Mn oxide coatings on bulk sediment are investigated as proxies for seawater Pb isotopes on Cenozoic time scales. Previous studies investigating long-term variations in weathering inputs and circulation patterns used Pb isotopes derived from Fe-Mn crust, but these crusts grow very slowly, are difficult to date, and have limited spatial resolution. Due to the slow growth rates they record a signal that is averaged over ~ 104-105 years, limiting the application to studies of long term changes. Initial results suggest that Pb isotopes extracted from Fe-Mn oxide coatings may be a proxy for more rapid variations in weathering and circulation. Comparison between the Pb isotopic values derived from these coatings and from fossil fish teeth for ~25 Ma old samples from ODP Site 1090 on the Aghulus Ridge (Southern Ocean) shows similar values, although there is a small systematic offset when plotted in 207Pb/204Pb vs. 206Pb/204Pb and 208Pb/204Pb vs.206Pb/204Pb space. This may be due to initial Pb concentrations in the hydroxyapatite of fossil fish teeth. Initial data from oxide coatings indicate a well-defined inverse correlation between values for ?Nd compared to 206Pb/204Pb, 207Pb/204Pb, and 208Pb/204Pb for samples ranging from 15-45 Ma at ODP Site 1090. Previous studies argue that the Nd isotopic variations at this site are largely driven by circulation, specifically the opening of Drake Passage followed by the influx of North Atlantic waters in response to development of the Antarctic Circumpolar Current (ACC) (Scher and Martin 2004, 2006 and in review). This correlation between the two isotopic systems suggests the Pb isotopic record is also dominated by a circulation signal. A 207Pb/204Pb vs. 206Pb/204Pb plot illustrates that Pb isotopic values varied over this interval as a function of the relative influx of Atlantic and Pacific waters, with the introduction of less radiogenic Pacific values indicating opening of Drake Passage, followed by the introduction of more radiogenic Atlantic waters. It is intriguing that Atlantic Pb signals are carried as far as the Southern Oceans given the short residence time of Pb (50-200yrs). Increased variability of Pb isotopic data and a decreased correlation to ? Nd values from 20 Ma and younger may record variations in more local weathering inputs.

  8. 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.

  9. Enhanced encapsulation of metoprolol tartrate with carbon nanotubes as adsorbent

    Science.gov (United States)

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

    2011-12-01

    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.

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

    International Nuclear Information System (INIS)

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

  11. Molecular filtration : the study of adsorbents

    OpenAIRE

    Twumasi, Ebenezer

    2011-01-01

    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...

  12. A novel fiber-based adsorbent technology

    Energy Technology Data Exchange (ETDEWEB)

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

    1997-10-01

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

  13. Quantification of trace metals in adsorbents

    International Nuclear Information System (INIS)

    Full text: Adsorbents are porous materials used to remove contaminants from water supplies. Presently, the quantitative trace metal analysis of adsorbents has been carried out using atomic absorption spectroscopy (AAS) and neutron activation analyses (NAA) despite these techniques having many inherent problems. We have used the technique of particle induced x-ray emission (PIXE) to overcome some of the current problems associated with the current techniques and compared the results against NAA and AAS. The results indicate that PIXE is capable of quantifying trace metals in adsorbents although some issues need to be resolved relating to the inhomogeneous internal structure of the adsorbent. Copyright (2005) Australian Institute of Physics

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

    Directory of Open Access Journals (Sweden)

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

    2011-10-01

    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.

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

    Directory of Open Access Journals (Sweden)

    A. Dudek

    2008-09-01

    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.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2014-04-30

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

  17. 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

  18. Filter-adsorber aging assessment

    International Nuclear Information System (INIS)

    An aging assessment of high-efficiency particulate (HEPA) air filters and activated carbon gas adsorption units was performed by the Pacific Northwest Laboratory as part of the U.S. Nuclear Regulatory Commission's (USNRC) Nuclear Plant Aging Research (NPAR) Program. This evaluation of the general process in which characteristics of these two components gradually change with time or use included the compilation of information concerning failure experience, stressors, aging mechanisms and effects, and inspection, surveillance, and monitoring methods (ISMM). Stressors, the agents or stimuli that can produce aging degradation, include heat, radiation, volatile contaminants, and even normal concentrations of aerosol particles and gasses. In an experimental evaluation of degradation in terms of the tensile breaking strength of aged filter media specimens, over forty percent of the samples did not meet specifications for new material. Chemical and physical reactions can gradually embrittle sealants and gaskets as well as filter media. Mechanisms that can lead to impaired adsorber performance are associated with the loss of potentially available active sites as a result of the exposure of the carbon to airborne moisture or volatile organic compounds. Inspection, surveillance, and monitoring methods have been established to observe filter pressure drop buildup, check HEPA filters and adsorbers for bypass, and determine the retention effectiveness of aged carbon. These evaluatifectiveness of aged carbon. These evaluations of installed filters do not reveal degradation in terms of reduced media strength but that under normal conditions aged media can continue to effectively retain particles. However, this degradation may be important when considering the likelihood of moisture, steam, and higher particle loadings during severe accidents and the fact it is probable that the filters have been in use for an extended period

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

    Science.gov (United States)

    Hu, Baiyang; Fugetsu, Bunshi; Yu, Hongwen; Abe, Yoshiteru

    2012-05-30

    We developed a spongiform adsorbent that contains Prussian blue, which showed a high capacity for eliminating cesium. An in situ synthesizing approach was used to synthesize Prussian blue inside diatomite cavities. Highly dispersed carbon nanotubes (CNTs) were used to form CNT networks that coated the diatomite to seal in the Prussian blue particles. These ternary (CNT/diatomite/Prussian-blue) composites were mixed with polyurethane (PU) prepolymers to produce a quaternary (PU/CNT/diatomite/Prussian-blue), spongiform adsorbent with an in situ foaming procedure. Prussian blue was permanently immobilized in the cell walls of the spongiform matrix and preferentially adsorbed cesium with a theoretical capacity of 167 mg/g cesium. Cesium was absorbed primarily by an ion-exchange mechanism, and the absorption was accomplished by self-uptake of radioactive water by the quaternary spongiform adsorbent. PMID:22464752

  20. NOx adsorber and method of regenerating same

    Science.gov (United States)

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

    2007-01-30

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

  1. Fluorescence dynamics of microsphere-adsorbed sunscreens

    Science.gov (United States)

    Krishnan, R.

    2005-03-01

    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.

  2. 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.

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

    Directory of Open Access Journals (Sweden)

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

    2013-08-01

    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.

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

    International Nuclear Information System (INIS)

    Highlights: • The PEO coating growth rate increased with the cathodic voltage increasing. • Higher cathodic voltage resulted in more compact coating structure. • The compact structure led to low surface roughness and high wear resistance. - Abstract: 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

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

    Energy Technology Data Exchange (ETDEWEB)

    Li, Qingbiao [State Key Laboratory of Solid Lubrication, Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences, Lanzhou 730000 (China); School of Science, Lanzhou University of Technology, Lanzhou 730050 (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); Liu, Baixing; Peng, Zhenjun [State Key Laboratory of Solid Lubrication, Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences, Lanzhou 730000 (China); Wang, Qing [School of Science, Lanzhou University of Technology, Lanzhou 730050 (China)

    2014-04-01

    Highlights: • The PEO coating growth rate increased with the cathodic voltage increasing. • Higher cathodic voltage resulted in more compact coating structure. • The compact structure led to low surface roughness and high wear resistance. - Abstract: 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 ?-Al{sub 2}O{sub 3} 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.

  6. Wear Behavior of Plasma-Sprayed Carbon Nanotube-Reinforced Aluminum Oxide Coating in Marine and High-Temperature Environments

    Science.gov (United States)

    Keshri, Anup Kumar; Agarwal, Arvind

    2011-12-01

    Wear behavior of plasma-sprayed carbon nanotube (CNT)-reinforced aluminum oxide (Al2O3) composite coatings are investigated at room temperature (298 K), elevated temperature (873 K), and in sea water. Lowest wear volume loss was observed in the sea water as compared to dry sliding at 298 and 873 K. Relative improvement in the wear resistance of Al2O3-8 wt.% CNT coating compared to Al2O3 was 72% at 298 K, 76% at 873 K, and 66% in sea water. The improvement in the wear resistance of Al2O3-CNT coatings is attributed to (i) larger area coverage by protective film on the wear surface at room temperature and in sea water, (ii) higher fracture toughness of Al2O3-CNT coatings due to CNT bridging between splats, and (iii) anti-friction effect of sea water. The average coefficient of friction (COF) was the lowest (0.55) in sea water and the highest (0.83) at 873 K for Al2O3-8 wt.% CNT coating.

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

    KAUST Repository

    Saleh, Mohamed A.

    2013-05-15

    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.

  8. Site blocking effects on adsorbed polyacrylamide conformation

    Science.gov (United States)

    Brotherson, Brett A.

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

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

    Science.gov (United States)

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

    2012-07-01

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

  10. Inorganic chemically active adsorbents (ICAAs)

    Energy Technology Data Exchange (ETDEWEB)

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

    1997-10-01

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

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2010-07-01

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

  12. Characterization of adsorbed dicarbonyls of rhodium

    International Nuclear Information System (INIS)

    We have studies the adsorbed states of CO on dispersed RH in Y zeolites by solid-state 13C NMR spectroscopy. The structure of the dicarbonyl form of adsorbed rhodium has been revealed using a Carr-Purcell-Meiboom-Gill multiple pulse sequence. NMR lineshape calculations show that adsorbed Rh(CO)2 species are undergoing a 180 deg. flipping motion about the C2 axis which bisects the C-Rh-C angle. Spectra calculated with this motional model have been compared with published spectra of CO on Rh-Y zeolites. (author). 7 refs.; 3 figs

  13. Composite

    Science.gov (United States)

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

    2014-06-01

    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.

  14. Composites

    Science.gov (United States)

    Taylor, John G.

    The Composites market is arguably the most challenging and profitable market for phenolic resins aside from electronics. The variety of products and processes encountered creates the challenges, and the demand for high performance in critical operations brings value. Phenolic composite materials are rendered into a wide range of components to supply a diverse and fragmented commercial base that includes customers in aerospace (Space Shuttle), aircraft (interiors and brakes), mass transit (interiors), defense (blast protection), marine, mine ducting, off-shore (ducts and grating) and infrastructure (architectural) to name a few. For example, phenolic resin is a critical adhesive in the manufacture of honeycomb sandwich panels. Various solvent and water based resins are described along with resin characteristics and the role of metal ions for enhanced thermal stability of the resin used to coat the honeycomb. Featured new developments include pultrusion of phenolic grating, success in RTM/VARTM fabricated parts, new ballistic developments for military vehicles and high char yield carbon-carbon composites along with many others. Additionally, global regional market resin volumes and sales are presented and compared with other thermosetting resin systems.

  15. Spherical Adsorbers and Catalysts from Aluminium Oxides

    International Science & Technology Center (ISTC)

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

  16. 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)

  17. Adsorption of p-Nitrophenol (PNP) on new adsorbents prepared from diatomite and charcoal

    International Nuclear Information System (INIS)

    Increasing attention has been paid to mesoporous materials with high surface area and narrow pore size distribution because of their diverse applications (e. g., adsorbents, catalysts, and host materials). Inorganic composite materials (ICM) prepared by a mixture of natural diatomite (macroporous materials) and charcoal (microporous material) in particular operative conditions. (Author)

  18. Defluoridization Using a Natural Adsorbent, Strychnos Potatorum

    OpenAIRE

    S.Rayappan; B.Jeyaprabha

    2014-01-01

    The study assessed the suitability of low-cost natural adsorbent to effectively remediate fluoride contaminated water. The removal of fluoride from aqueous solution by using Strychnos Potatorum was studied in batch technique. Influence of pH, adsorbent dose, contact time, co ions, speed and initial concentration on the adsorption were investigated. The maximum removal of fluoride ion was obtained at pH 7. The removal of fluoride was expressed with Langmuir and Freundlich isotherm. It was foun...

  19. Regenerable activated bauxite adsorbent alkali monitor probe

    Science.gov (United States)

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

    1992-01-01

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

  20. Mesoporous Silica: A Suitable Adsorbent for Amines

    Directory of Open Access Journals (Sweden)

    Abdollahzadeh-Ghom Sara

    2009-01-01

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

  1. Thermal and Structural Stability of Adsorbed Proteins

    OpenAIRE

    Sharma, Sumit; Berne, B. J.; Kumar, Sanat K.

    2010-01-01

    Experimental evidence suggests that proteins adsorbed to hydrophobic surfaces at low coverages are stabilized relative to the bulk. For larger coverages, proteins unfold and form ?-sheets. We performed computer simulations on model proteins and found that: 1), For weakly adsorbing surfaces, unfolded conformations lose more entropy upon adsorption than folded ones. 2), The melting temperature, both in the bulk and at surfaces, decreases with increasing protein concentration because of favorab...

  2. Zeolites as alcohol adsorbents from aqueous solutions

    OpenAIRE

    Cekova Blagica; Kocev Dragi; Kolcakovska Elena; Stojanova Daniela

    2006-01-01

    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...

  3. Photochemistry of Nitrate Adsorbed on Mineral Dust

    Science.gov (United States)

    Gankanda, A.; Grassian, V. H.

    2013-12-01

    Mineral dust particles in the atmosphere are often associated with adsorbed nitrate from heterogeneous reactions with nitrogen oxides including HNO3 and NO2. Although nitrate ion is a well-studied chromophore in natural waters, the photochemistry of adsorbed nitrate on mineral dust particles is yet to be fully explored. In this study, wavelength dependence of the photochemistry of adsorbed nitrate on different model components of mineral dust aerosol has been investigated using transmission FTIR spectroscopy. Al2O3, TiO2 and NaY zeolite were used as model systems to represent non-photoactive oxides, photoactive semiconductor oxides and porous materials respectively, present in mineral dust aerosol. In this study, adsorbed nitrate is irradiated with 254 nm, 310 nm and 350 nm narrow band light. In the irradiation with narrow band light, NO2 is the only detectable gas-phase product formed from nitrate adsorbed on Al2O3 and TiO2. The NO2 yield is highest at 310 nm for both Al2O3 and TiO2. Unlike Al2O3 and TiO2, in zeolite, adsorbed nitrate photolysis to nitrite is observed only at 310 nm during narrow band irradiation. Moreover gas phase products were not detected during nitrate photolysis in zeolite at all three wavelengths. The significance of these differences as related to nitrate photochemistry on different mineral dust components will be highlighted.

  4. Quantitative Measurements of Adsorbate-Adsorbate Interactions at Solid-Liquid Interfaces

    Science.gov (United States)

    Taranovskyy, A.; Tansel, T.; Magnussen, O. M.

    2010-03-01

    The interactions between adsorbates at a solid-liquid interface were studied by video-rate STM for the case of sulfur on Cu(100) electrode surfaces in HCl solution. Quantitative data were obtained by analyzing the Sad dimer dynamics within the surrounding c(2×2)-Cl adlattice as well as the adsorbate configurations. The interactions are repulsive for Sad separated by one or two lattice spacings and attractive at a separation of 2 with energies comparable to adsorbates at the solid-vacuum interface. The Sad diffusion barriers are significantly reduced in the vicinity of a neighboring adsorbate.

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

    Energy Technology Data Exchange (ETDEWEB)

    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

    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.

  6. Removal of cyanide by eggshell as low-cost adsorbent

    Directory of Open Access Journals (Sweden)

    Ghorban Asgari

    2013-05-01

    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.

  7. 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

    OpenAIRE

    Yi Liu; Ryuichi Sugimoto; Katsuhiro Sumi

    2013-01-01

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

  8. Electrochemical behavior of LiFePO4 cathode materials in the presence of anion adsorbents

    International Nuclear Information System (INIS)

    The poor rate capability is a major problem of olivine-structured lithium iron phosphate (LFP) cathode material in lithium-ion batteries due to its low electric conductivity and sluggish lithium diffusion. Other than the custom strategies to solve this problem like carbon coating and nano-size treatment, we simply mixed LFP with some anion adsorbents, which can store anions from the electrolytes swiftly. The effect of anion adsorbents on the performance of LFP composite electrode has been investigated by cyclic voltammetric tests and the corresponding apparent lithium diffusion coefficients have been measured

  9. Scanning tunneling microscopy theory for an adsorbate: Application to adenine adsorbed on a graphite surface

    Science.gov (United States)

    Ou-Yang, Hui; Marcus, R. A.; Källebring, Bruno

    1994-05-01

    An expression is obtained for the current in scanning tunneling microscopy (STM) for a single adsorbate molecule. For this purpose the ``Newns-Anderson'' treatment (a ``discrete state in a continuum'' treatment) is used to obtain wave functions and other properties of the adsorbate/substrate system. The current is expressed in terms of the adsorbate-tip matrix elements, and an effective local density of states of the adsorbate/substrate system, at the adsorbate. As an example, the treatment is applied to the STM image of adenine adsorbed on a graphite surface, and the results are compared with experiment. The dependence of the image on the position of adenine with respect to the underlying graphite is considered. A discussion is given of the type of experimental STM data needed for suitable comparison of theory and experiment. In an analysis of the calculations, the role of each atom, its neighbors, next nearest neighbors, etc., in an adsorbed molecule is considered. The need for using in the present calculation more orbitals than only the HOMO and the LUMO of the adsorbate is also noted.

  10. 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)

    Moon, Ellen M.; Peacock, Caroline L.

    2012-09-01

    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.

  11. Titanium dioxide/zeolite catalytic adsorbent for the removal of NO and acetone vapors.

    Science.gov (United States)

    Jan, Yan-Huei; Lin, Liang-Yi; Karthik, Mani; Bai, Hsunling

    2009-10-01

    This study delineates a simple and versatile approach for the removal of nitrogen monoxide (NO) and volatile organic vapors over composites of titanium dioxide (TiO2) catalyst/zeolite adsorbent under ultraviolet (UV) irradiation at ambient temperature. The catalytic adsorbents with different TiO2/H-ZSM-5 zeolite ratios were prepared by a simple insipient wetness impregnation method. It was found that a 60%/40% weight ratio of TiO2/H-ZSM-5 composite is most effective and can achieve over 90% efficiency for the removal of NO and acetone vapors. This composite also showed a better long-term activity than that of bulk TiO2 photocatalyst or zeolite adsorbent. The experimental results revealed that photocatalytic decomposition of NO was dramatically enhanced in the presence of acetone. NO also promoted the acetone oxidation under humid conditions. Furthermore, the co-existence of acetone and NO in the gaseous stream could reduce acid accumulation on the surface of the catalyst as confirmed by Fourier-transform infrared spectroscopy. Thus, the TiO2/zeolite catalytic adsorbent could have a high potential for the removal of multiple air pollutants in the indoor air environment. PMID:19842326

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

    International Nuclear Information System (INIS)

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

  13. A theory of adsorbate melting near the surfaces of adsorbents and in slit-shaped pores

    Science.gov (United States)

    Tovbin, Yu. K.

    2014-06-01

    Molecular principles of a theory of adsorbate melting near the open surfaces of adsorbents in the frozen state or in slit-shaped pores are discussed. The states of liquid and crystalline adsorbates are described in terms of a single molecular approach (the lattice gas model). The crystalline state is described using the concept of quasi-average distributions, for which the degeneracy of the density distribution function in the plane of the adsorbent is eliminated. Equations for the chemical potential of the adsorbate in defective crystals and vapor-liquid systems are derived with allowance for their vibrational motion, making it possible to calculate the concentration profile of the substance at the planar interface between two solid phases, between a solid and a liquid, and inside a slit-shaped pore.

  14. Defluoridization Using a Natural Adsorbent, Strychnos Potatorum

    Directory of Open Access Journals (Sweden)

    S.Rayappan

    2014-10-01

    Full Text Available The study assessed the suitability of low-cost natural adsorbent to effectively remediate fluoride contaminated water. The removal of fluoride from aqueous solution by using Strychnos Potatorum was studied in batch technique. Influence of pH, adsorbent dose, contact time, co ions, speed and initial concentration on the adsorption were investigated. The maximum removal of fluoride ion was obtained at pH 7. The removal of fluoride was expressed with Langmuir and Freundlich isotherm. It was found that the sufficient time for adsorption equilibrium of fluoride ion was 1 hour. The removal of fluoride ions was maximum for the adsorbent dosage of SP is 50mg/50ml. The fluoride adsorption was maximum at 60minutes. The adsorption of F- ion was maximum in the shaking speed of 120 rpm. The presence of interfering ions such as nitrate and carbonate showed positive effect while sulphate and chloride showed little negative effect and phosphate showed high negative effect for the adsorbent. The optimum initial fluoride concentration for SP adsorbent was 1mg/50ml.

  15. Protein purification using magnetic adsorbent particles

    DEFF Research Database (Denmark)

    Franzreb, M; Siemann-Herzberg, M.

    2006-01-01

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

  16. The dynamics and structures of adsorbed surfaces

    International Nuclear Information System (INIS)

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

  17. The Dynamics and Structures of Adsorbed Surfaces

    DEFF Research Database (Denmark)

    Nielsen, M; Ellenson, W. D.

    1978-01-01

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

  18. Microarc oxidized TiO2 based ceramic coatings combined with cefazolin sodium/chitosan composited drug film on porous titanium for biomedical applications.

    Science.gov (United States)

    Wei, Daqing; Zhou, Rui; cheng, Su; Feng, Wei; Li, Baoqiang; Wang, Yaming; Jia, Dechang; Zhou, Yu; Guo, Haifeng

    2013-10-01

    Porous titanium was prepared by pressureless sintering of titanium beads with diameters of 100, 200, 400 and 600 ?m. The results indicated that the mechanical properties of porous titanium changed significantly with different bead diameters. Plastic deformations such as necking phenomenon and dimple structure were observed on the fracture surface of porous titanium sintered by beads with diameter of 100 ?m. However, it was difficult to find this phenomenon on the porous titanium with a titanium bead diameter of 600 ?m. The microarc oxidized coatings were deposited on its surface to improve the bioactivity of porous titanium. Furthermore, the cefazolin sodium/chitosan composited films were fabricated on the microarc oxidized coatings for overcoming the inflammation due to implantation, showing good slow-release ability by addition of chitosan. And the release kinetic process of cefazolin sodium in composited films could be possibly fitted by a polynomial model. PMID:23910322

  19. Standoff spectroscopy of surface adsorbed chemicals.

    Science.gov (United States)

    Van Neste, C W; Senesac, L R; Thundat, T

    2009-03-01

    Despite its immediate applications, selective detection of trace quantities of surface adsorbed chemicals, such as explosives, without physically collecting the sample molecules is a challenging task. Standoff spectroscopic techniques offer an ideal method of detecting chemicals without using a sample collection step. Though standoff spectroscopic techniques are capable of providing high selectivity, their demonstrated sensitivities are poor. Here we describe standoff detection of trace quantities of surface adsorbed chemicals using two quantum cascade lasers operated simultaneously, with tunable wavelength windows that match with absorption peaks of the analytes. This standoff method is a variation of photoacoustic spectroscopy, where scattered light from the sample surface is used for exciting acoustic resonance of the detector. We demonstrate a sensitivity of 100 ng/cm(2) and a standoff detection distance of 20 m for surface adsorbed analytes such as explosives and tributyl phosphate. PMID:19186935

  20. Properties of adsorbed hydrogen films in nanospaces

    Science.gov (United States)

    Dohnke, Elmar; Gillespie, Andrew; Pfeifer, Peter

    2015-03-01

    Various high surface area materials were evaluated for their gas storage properties. From supercritical hydrogen isotherms at 77 Kelvin, we estimated the adsorbed film densities, film thicknesses and intrapore gas densities. Intrapore gas density is a measurement of the average hydrogen density within a pore. Furthermore, we investigated the correlation between the isosteric heat of adsorption, surface chemistry, and pore size distribution with an adsorbed film. In most of the samples both saturated film densities and intrapore gas densites exceed the liquid hydrogen density at 1 bar and 20 Kelvin. The saturated film density surpassed it even by 40%. The adsorbed film seems to be independent of the isosteric heat of adsorption or the samples pore size distribution. They behave like a universal constant for all carbon-based surfaces.

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

    Energy Technology Data Exchange (ETDEWEB)

    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

    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.

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

    International Nuclear Information System (INIS)

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

  3. Thermodynamics of alloyed nanoparticles for hydrogen evolution reaction including configurational and adsorbate effects

    Science.gov (United States)

    Wang, Lin-Lin; Tan, Teck L.; Johnson, Duane D.

    2015-03-01

    Changes in the chemical configuration of alloyed nanoparticle (NP) catalysts induced by adsorbates under working conditions are crucial to understand and design NP functionality. We extend the cluster expansion method to predict the configurational thermodynamics of alloyed NPs on equal footing with adsorbate thermodynamics based on density functional theory data. Exemplified with alloyed PdPt NPs having H-coverage up to a full layer, we describe both the configurational and adsorbate thermodynamics behavior simultaneously across the entire range of NP composition and H-coverage to obtain the H-adsorption isotherms and simulated cyclic voltammetry for hydrogen evolution reaction. Changes in the chemical configuration of alloyed nanoparticle (NP) catalysts induced by adsorbates under working conditions are crucial to understand and design NP functionality. We extend the cluster expansion method to predict the configurational thermodynamics of alloyed NPs on equal footing with adsorbate thermodynamics based on density functional theory data. Exemplified with alloyed PdPt NPs having H-coverage up to a full layer, we describe both the configurational and adsorbate thermodynamics behavior simultaneously across the entire range of NP composition and H-coverage to obtain the H-adsorption isotherms and simulated cyclic voltammetry for hydrogen evolution reaction. Supported by DOE-BES CSGB (DE-FG02-03ER15476), MSE (DE-AC02-07CH1135) and Ames Lab LDRD. Research was performed at the Ames Laboratory, which is operated for DOE by Iowa State University under Contract DE-AC02-07CH11358.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2010-07-15

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

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

    International Nuclear Information System (INIS)

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

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

    Science.gov (United States)

    Deng, Shubo; Li, Zhijian; Huang, Jun; Yu, Gang

    2010-07-15

    Different metal doped TiO(2) adsorbents were prepared through the precipitation and hydrolysis-precipitation methods. The novel Ce-Ti oxide adsorbent obtained by the hydrolysis-precipitation had much higher sorption capacity for As(V) than both the pure titanium dioxide and cerium oxide adsorbents, and the preparation conditions including the Ti/Ce molar ratio and polyvinyl alcohol (PVA) content were optimized. Environmental scanning electronic microscopy (ESEM) and X-ray diffraction (XRD) spectroscopic investigations revealed that the amorphous Ce-Ti hybrid adsorbent was composed of some nanoparticles in the size range of 100-200 nm, which aggregated to form the porous hybrid adsorbents, and the amorphous compositions and the small nanoparticles were related to the high sorption capacity for As(V). Batch sorption experiments including sorption kinetics, isotherm, effect of pH and competitive ions were investigated. The Ce-Ti adsorbent exhibited high sorption capacity for As(V) at pH below 7. Column studies showed that about 72,085 bed volumes of As(V) solution at the concentration of 50 microg L(-1) and pH 6.5 were filtered when As(V) concentration in the effluent increased to 10 microg L(-1), and the average sorption capacity of As(V) on the Ce-Ti adsorbent was about 9.4 mg g(-1). PMID:20403658

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

    International Nuclear Information System (INIS)

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

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2012-05-30

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

  9. 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.

  10. Fly ash adsorbents for multi-cation wastewater treatment

    Science.gov (United States)

    Visa, Maria; Isac, Luminita; Duta, Anca

    2012-06-01

    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.

  11. 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

  12. NUCLEAR MAGNETISM OF ADSORBED 3He

    OpenAIRE

    Godfrin, H.; Ruel, R.; Osheroff, D.

    1988-01-01

    The nuclear magnetism of atomic layers of 3He adsorbed on graphite has been studied by NMR measurements of the magnetization, line shifts and thermal time constants. The properties of this novel system are well described by the two-dimensional ferromagnetic Heisenberg Hamiltonian.

  13. Heterogeneous membranes filled with hypercrosslinked microparticle adsorbent.

    Czech Academy of Sciences Publication Activity Database

    Hradil, Ji?í; Krystl, V.; Hrabánek, P.; Bernauer, B.; Ko?i?ík, Milan

    2005-01-01

    Ro?. 65, 1-2 (2005), s. 57-68. ISSN 1381-5148 R&D Projects: GA ?R GA104/03/0680 Institutional research plan: CEZ:AV0Z40500505 Keywords : heterogeneous membranes * hypercrosslinked adsorbent * microparticles Subject RIV: CD - Macromolecular Chemistry Impact factor: 1.565, year: 2005

  14. Photoemission spectroscopy of surfaces and adsorbates

    International Nuclear Information System (INIS)

    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

  15. REVIEW: USE of COMPOSITE ADSORBENTS in ADSORPTION REFRIGERATION

    OpenAIRE

    Satishchandra V. Joshi; Vaibhav N. Deshmukh

    2012-01-01

    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...

  16. Surface redox reactions of cobaltocene adsorbed onto pyrolytic graphite (HOPG)

    Science.gov (United States)

    Henrion, O.; Jaegermann, W.

    1997-10-01

    Cobaltocene was adsorbed in UHV at 100 K onto cleaved pyrolytic graphite. The adsorbate bonding as well as the electronic properties of the interface were investigated by UPS and XPS. For cobaltocene exposures annealing to room temperature, the molecularly adsorbed species is desorbed. The potentials and adsorbate DOS at the interface are interpreted in terms of an electrochemical redox equilibrium and compared with electrolyte solutions.

  17. Zeolites as alcohol adsorbents from aqueous solutions

    Directory of Open Access Journals (Sweden)

    Cekova Blagica

    2006-01-01

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

  18. 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

  19. Non-Equilibrium in Adsorbed Polymer Layers

    CERN Document Server

    O'Shaughnessy, B

    2005-01-01

    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...

  20. Curvature Elasticity of an Adsorbed Polymer Layer

    OpenAIRE

    Clement, F.; Joanny, J.-F.

    1997-01-01

    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...

  1. Kenaf Core as CO2 Adsorbent

    Directory of Open Access Journals (Sweden)

    N. Zaini

    2014-01-01

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

  2. Limited Range Fractality of Randomly Adsorbed Rods

    OpenAIRE

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

    1997-01-01

    Multiple resolution analysis of two dimensional structures composed of randomly adsorbed penetrable rods, for densities below the percolation threshold, has been carried out using box-counting functions. It is found that at relevant resolutions, for box-sizes, $r$, between cutoffs given by the average rod length $$ and the average inter-rod distance $r_1$, these systems exhibit apparent fractal behavior. It is shown that unlike the case of randomly distributed isotropic obje...

  3. Activity of Aflatoxins Adsorbents in Poultry Feed

    Directory of Open Access Journals (Sweden)

    Yasmin Mussaddeq

    2000-01-01

    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.

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

    International Nuclear Information System (INIS)

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

  5. A novel adsorbent obtained by inserting carbon nanotubes into cavities of diatomite and applications for organic dye elimination from contaminated water.

    Science.gov (United States)

    Yu, Hongwen; Fugetsu, Bunshi

    2010-05-15

    A novel approach is described for establishing adsorbents for elimination of water-soluble organic dyes by using multi-walled carbon nanotubes (MWCNTs) as the adsorptive sites. Agglomerates of MWCNTs were dispersed into individual tubes (dispersed-MWCNTs) using sodium n-dodecyl itaconate mixed with 3-(N,N-dimethylmyristylammonio)-propanesulfonate as the dispersants. The resultant dispersed-MWCNTs were inserted into cavities of diatomite to form composites of diatomite/MWCNTs. These composites were finally immobilized onto the cell walls of flexible polyurethane foams (PUF) through an in situ PUF formation process to produce the foam-like CNT-based adsorbent. Ethidium bromide, acridine orange, methylene blue, eosin B, and eosin Y were chosen to represent typical water-soluble organic dyes for studying the adsorptive capabilities of the foam-like CNT-based adsorbent. For comparisons, adsorptive experiments were also carried out by using agglomerates of the sole MWCNTs as adsorbents. The foam-like CNT-based adsorbents were found to have higher adsorptive capacities than the CNT agglomerates for all five dyes; in addition, they are macro-sized, durable, flexible, hydrophilic and easy to use. Adsorption isotherms plotted based on the Langmuir equation gave linear results, suggesting that the foam-like CNT-based adsorbent functioned in the Langmuir adsorption manner. The foam-like CNT-based adsorbents are reusable after regeneration with aqueous ethanol solution. PMID:20045251

  6. Detecting Adsorbed Sulfate and Phosphate on Nanophase Weathering Products on Mars

    Science.gov (United States)

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

    2012-12-01

    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.

  7. Insights into the origin of the separation selectivity with silica hydride adsorbents.

    Science.gov (United States)

    Kulsing, Chadin; Nolvachai, Yada; Marriott, Philip J; Boysen, Reinhard I; Matyska, Maria T; Pesek, Joseph J; Hearn, Milton T W

    2015-02-19

    In this study, the surface properties of type-B silica have been compared with an unmodified silica hydride phase, a diamond hydride phase and silica hydride phases modified with bidentate anchored octyl (BDC8), bidentate anchored octadecyl (BDC18), phenyl and cholesteryl groups. Atomic distributions of the surface elemental composition of each type of stationary phase were determined using energy-dispersive X-ray spectroscopy. For the type-B silica, unmodified silica hydride, diamond hydride as well as BDC18 and cholesteryl silica hydride phases, the increase in carbon contents correlated with more negative surface ? potential values (R(2) = 0.92). The origin of these more negative ? potentials has been evaluated with mobile phases up to 100% (v/v) methanol content, with this property attributed to either an increase in the amount of adsorbed hydroxide ions or a decrease in the amount of adsorbed protons on the surfaces modified silica hydride phases of higher carbon content. This property of chemically modified silica hydride phases is in accordance with the unique propensity for hydroxide ions to be preferentially adsorbed onto hydrophobic surfaces of low permittivity and effects due to the specific accumulated water molecules associated with the electrical interfacial double layer of the adsorbent. PMID:25656442

  8. A novel magnetic 4A zeolite adsorbent synthesised from kaolinite type pyrite cinder (KTPC)

    Science.gov (United States)

    Wang, Weiqing; Feng, Qiming; Liu, Kun; Zhang, Guofan; Liu, Jing; Huang, Yang

    2015-01-01

    As a solid waste, kaolinite type pyrite cinder (KTPC) is a special pyrite cinder, its mineral components include metakaolin and magnetite, and the chemical compositions of these minerals include SiO2, Al2O3, FeO and Fe2O3. In this study, a novel magnetic 4A zeolite adsorbent was synthesised from KTPC using the hydrothermal method, and the optimum hydrothermal synthesis conditions were investigated using X-ray diffraction (XRD) and by determining the specific surface area (SSA) and the saturated cation exchange adsorption capacity (SCEAC) to Cs+. Under the optimum hydrothermal synthesis conditions, the magnetic 4A zeolite adsorbent can be synthesised with high crystallinity, and the SSA and SCEAC to Cs+ are 24.49 m2/g and 106.63 mg/g, respectively. The further characterisations of pore size distribution, scanning electron microscopy (SEM), energy dispersive X-ray (EDX), thermogravimetry-derivative thermogravimetry-differential thermal analysis (TG-DTG-DTA), Fourier transform infrared spectroscopy (FTIR), vibrating sample magnetometer (VSM) were performed. The results revealed that magnetic particles are coated onto the zeolite surface and further form magnetic aggregates, and the existing magnetic particles in KTPC do not change their crystal structure and do not affect the synthesis of the 4A zeolite. In addition, the synthesised 4A zeolite adsorbent can be used as a magnetic adsorbent in wastewater treatment with high magnetic sensitivity and is thermally stable up to approximately 900 °C.

  9. Surface phase separation in complex mixed adsorbing systems: An interface-bulk coupling effect

    Science.gov (United States)

    Pugnaloni, Luis A.; Ettelaie, Rammile; Dickinson, Eric

    2004-08-01

    The interfacial thermodynamics and structure of ternary mixtures of the type A+B+solvent are investigated. According to the Gibbs phase rule, the coupling between the bulk phase and the interfacial region—which is related to the reversibility of the adsorption of the corresponding species—is a determinant as to whether phase separation can be observed at the interface. For an n-component adsorbing solution, at least one of the species has to adsorb irreversibly over the experimental time scales in order not to fix more intensive variables than those required to observe surface phase separation. We present results for a lattice model planar interface consisting of the ternary mixture A+B+solvent. The solvent molecules and the type A molecules have fixed chemical potentials at the interface since they are equilibrated with a bulk solution. In contrast, the type B molecules are irreversibly adsorbed at the interface and do not equilibrate with the bulk. Mean-field theory is compared with Monte Carlo simulation. Interestingly, the spinodal line in the interaction-composition plane shows a reentrant on the B-rich phase side. We discuss the implications of these results for surface phase separation of adsorbing mixtures of proteins and low-molecular-weight surfactants.

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

    Energy Technology Data Exchange (ETDEWEB)

    Kenny, T.W.

    1989-05-01

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

  11. 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

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

    Directory of Open Access Journals (Sweden)

    Bondar I.V.

    2012-08-01

    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.

  13. Stability constants for silicate adsorbed to ferrihydrite

    DEFF Research Database (Denmark)

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

    1994-01-01

    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.

  14. Conformational Properties of an Adsorbed Charged Polymer

    CERN Document Server

    Cheng, C H; Cheng, Chi-Ho; Lai, Pik-Yin

    2004-01-01

    The behavior of a strongly charged polymer adsorbed on an oppositely charged surface of low-dielectric constant is formulated by the functional integral method. By separating the translational, conformational, and fluctuational degrees of freedom, the scaling behaviors for both the height of the polymer and the thickness of the diffusion layer are determined. Unlike the results predicted by scaling theory, we identified the continuous crossover from the weak compression to the compression regime. All teh analytical results are found to be consistent with Monte-Carlo simulations. Finally, an alternative (operational) definition of a charged polymer adsorption is proposed.

  15. Spectroscopy and dynamics of orientationally structured adsorbates

    CERN Document Server

    Rozenbaum, V M

    2002-01-01

    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

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

    International Nuclear Information System (INIS)

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

  17. 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)

  18. The existing forms of adsorbed Cr in sediment

    International Nuclear Information System (INIS)

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

  19. Video STM Studies of Adsorbate Diffusion at Electrochemical Interfaces

    Science.gov (United States)

    Tansel, T.; Magnussen, O. M.

    2006-01-01

    Direct in situ studies of the surface diffusion of isolated adsorbates at an electrochemical interface by high-speed scanning tunneling microscopy (video STM) are presented for sulfide adsorbates on Cu(100) in HCl solution. As revealed by a quantitative statistical analysis, the adsorbate motion can be described by thermally activated hopping between neighboring adsorption sites with an activation energy that increases linearly with electrode potential by 0.50 eV per V. This can be explained by changes in the adsorbate dipole moment during the hopping process and contributions from coadsorbates.

  20. Ageing of GA-J adsorbents for iodine filters

    International Nuclear Information System (INIS)

    The results are reported of a laboratory study into the static and dynamic ageing of adsorbent GA-J for iodine filters in nuclear power plants. The adsorbent ageing was assessed using the standard test of the efficiency of capture of 131I-labelled CH3I. It was found that the reduction in adsorbent efficiency due to static ageing was insignificant (approx. 2% per year) while the efficiency reduction due to dynamic ageing was marked. It was about 40% over one year of exposure to ambient air and was mainly due to adsorbent poisoning. (author)

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

    CERN Document Server

    Dabo, Ismaila

    2012-01-01

    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...

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

    DEFF Research Database (Denmark)

    Grabow, Lars; Larsen, Britt Hvolbæk

    2010-01-01

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

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2014-08-01

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

  4. NOx Removal and Effect of Adsorbate-Adsorbate Interactions

    DEFF Research Database (Denmark)

    Khan, Tuhin Suvra

    2013-01-01

    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.

  5. Composite 5A zeolite with ultrathin porous TiO2 coating for selective gas adsorption.

    Science.gov (United States)

    Song, Zhuonan; Huang, Yi; Wang, Lei; Li, Shiguang; Yu, Miao

    2015-01-01

    A composite zeolite adsorbent was prepared by conformally depositing an ultrathin porous TiO2 coating on the external surface of the 5A zeolite by molecular layer deposition (MLD) and subsequent calcination. The composite adsorbent showed significantly improved ideal adsorption selectivity for CO2-CH4, CO2-N2 and propylene-propane. PMID:25406720

  6. 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

  7. Limited Range Fractality of Randomly Adsorbed Rods

    CERN Document Server

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

    1997-01-01

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

  8. Nonlinear optical studies of molecular adsorbates

    International Nuclear Information System (INIS)

    In recent years, the possibility of employing laser interaction with surfaces as a surface diagnostic tool has attracted a great deal of attention. Optical second harmonic generation (SHG) and sum-frequency generation (SFG) have been proven to be most effective and versatile for surface and interfacial studies. By symmetry, these processes are forbidden in media with centrosymmetry, and can therefore be highly surface-specific. They have the advantages of being capable of high spatial temporal and spectral resolutions, suitable for in-situ, remote sensing of samples in hostile environment and applicable to all interfaces accessible to light. Indeed, they have been applied with great success to a large variety of surface and interfacial problems: probing adsorption and desorption of molecules from surfaces, measuring average molecular orientation of adsorbates, monitoring surface symmetry and surface phase transitions, conducting surface microscopy and spectroscopy, and many others. Here, we shall describe a few experiments recently carried out in our laboratory using these techniques

  9. The Stationary States of Adsorbed Hydrogen

    Science.gov (United States)

    Olsen, Raina; Taub, Haskell; Wexler, Carlos

    2012-02-01

    In order to investigate the impact of quantum effects on hydrogen adsorption, it is important to understand the stationary states occupied by adsorbed hydrogen molecules. We present experimental inelastic neutron scattering spectra which provide evidence for significant mixing of degrees of freedom which are normally decoupled in free space. Results suggest that simultaneous treatment of translational and rotational degrees of freedom and consideration of the potential corrugation are necessary for improved theoretical understanding of the problem. Numerical calculations of the full five dimensional single body potential are used to understand the origins of the experimentally observed stationary states. In addition, we briefly discuss how our results may be used to understand the shape of hydrogen adsorption isotherms.

  10. Effects of cathode current density on structure and corrosion resistance of plasma electrolytic oxidation coatings formed on ZK60 Mg alloy

    International Nuclear Information System (INIS)

    Current density is a key factor in plasma electrolytic oxidation (PEO) process. The aim of this paper is to study the effects of cathode current density on the composition, morphology, and corrosion resistance of ceramic coatings on ZK60 magnesium alloy prepared through bi-polar plasma electrolytic oxidation in Na3PO4 solution. The phase composition, morphology, and corrosion resistance were studied by X-ray Diffraction (XRD), Scanning Electron Microscope (SEM), Electrochemical Impedance Spectroscopy (EIS) and potentiodynamic polarization in 3.5% NaCl solution. It is found that the as-produced coatings are only composed of MgO. The increase of cathode current density made the coatings less porous and more compact. Analysis of EIS and potentiodynamic polarization technique on the samples shows that the corrosion resistance of the coated samples is better than that of ZK60 magnesium alloy, and that a bigger cathode current density can improve the corrosion resistance of as-prepared coatings.

  11. 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.

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

    Science.gov (United States)

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

    2014-11-01

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

  13. Flow boundary conditions for chain-end adsorbing polymer blends

    CERN Document Server

    Zhou, X; Site, L D; Kremer, K

    2005-01-01

    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 non-monotonic dependence of the slip length on the surface concentration of the adsorbed ends.

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

    International Nuclear Information System (INIS)

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

  15. Tribological properties of adsorbed PEO nanolayers on planar solids

    Science.gov (United States)

    Zeng, Wenduo; Jiang, Naisheng; Lindberg, Jake; Endoh, Maya K.; Koga, Tadanori

    2015-03-01

    We report tribological properties of irreversibly adsorbed poly(ethylene-oxide) (PEO) nanolayers onto planar Si substrates. The adsorbed nanolayers (~ 3 nm in thickness) were derived from spin-cast polymer thin films (~ 50 nm in thickness) via thermal annealing and subsequent solvent leaching with water. We characterized the formation process of the adsorbed nanolayers and the detailed surface/film structures by using x-ray reflectivity, grazing incidence x-ray diffraction, and atomic force microscopy. In addition, the contact angle and adhesive property of the adsorbed layers were characterized. We will discuss the structure-property relationship of the adsorbed nanolayers. T. K. acknowledges the partial financial support from NSF Grant No. CMMI-1332499.

  16. Pyrolyzed feather fibers for adsorbent and high temperature applications

    Science.gov (United States)

    Senoz, Erman

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

  17. Adsorption of mercury by carbonaceous adsorbents prepared from rubber of tyre wastes.

    Science.gov (United States)

    Manchón-Vizuete, E; Macías-García, A; Nadal Gisbert, A; Fernández-González, C; Gómez-Serrano, V

    2005-03-17

    Rubber from tyre wastes has been used to prepare carbonaceous adsorbents and the products obtained have been tested as adsorbents for mercury in aqueous solution. The adsorbents have been prepared by applying thermal, chemical and combined (thermal and chemical or vice versa) treatments. Tyre rubber has been: heated at 400 or 900 degrees C for 2 h in N2, chemically-treated with H2SO4, HNO3 or H2SO4/HNO3 solution for 24 h, and in two successive steps first heated at 400 degrees C for 2h in N2 and then treated with a H2SO4/HNO3 solution for 24 h, or vice versa. Resultant products have been characterised in terms of elementary composition and textural properties. The adsorption of mercury has been studied from kinetic and equilibrium standpoints. The treatments effected to tyre rubber decrease the carbon content and the hydrogen content. The oxygen content and the nitrogen content increase for the chemically-treated products. The heat treatment of tyre rubber results in a larger development of surface area, microporosity, and mesoporosity than the chemical treatments. These treatments, however, produce a great creation of macropores. In comparison to the starting rubber, the adsorption process of mercury is faster when the material is heated or treated with the H2SO4, HNO3 or 1:3 H2SO4/HNO3 solution. These adsorbents are either a non-porous solid or possess a high mesopore volume or a wide pore size distribution in the macropore range. The adsorption capacity is larger for products prepared by heat, chemical and combined treatments of the rubber. A common textural characteristic of these adsorbents is their better developed microporosity. The ability to adsorb mercury is higher for the heated products than for the chemically-treated ones. The maximum adsorption of mercury is 211 mg g(-1). The constant Kf of the Freundlich equation is as high as 108.9 mg g(-1). PMID:15752870

  18. Carbon dioxide pressure swing adsorption process using modified alumina adsorbents

    Science.gov (United States)

    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

    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.

  19. PHYSICAL CHARACTERIZATION AND DESULFURIZATION OF BIOBRIQUETTE USING CALCIUM-BASED ADSORBENT

    Directory of Open Access Journals (Sweden)

    Khairil

    2011-11-01

    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.

  20. 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

  1. Adsorbed block copolymer nanolayers on solids

    Science.gov (United States)

    Imbrogno, Jennifer; Sen, Mani; Kahn, Steven; Nishitsuji, Shotaro; Gowd, E. Bhoje; Endoh, Maya K.; Koga, Tadanori

    2015-03-01

    Directed self-assembly of block copolymers (BCP) has been used as an advanced lithography method. In this study, we aim to shed light onto the structures of BCP at the polymer melt-solid interface. Polystyrene-block-poly (4-vinylpyridine) (PS-b-P4VP) block copolymer was used. Spun-cast 32 nm PS-b-P4VP thick films on silicon substrates were (i) thermally annealed at high temperature above Tg of the polymers or (ii) solvent vapor annealing with chloroform (non-selective solvent) and subsequent 1-4, dioxane (selective solvent). Using atomic force microscopy (AFM), we found perpendicular hexagonally packed cylinders at the topmost surface of the resultant PS-b-P4VP films regardless of the annealing processing. In addition, to study the adsorbed layer structure, we rinsed the annealed films with toluene and characterized the morphologies and film structures using grazing incidence small-angle X-ray scattering, x-ray reflectivity and AFM. The details will be discussed.

  2. A new endotoxin adsorber: first clinical application.

    Science.gov (United States)

    Ullrich, H; Jakob, W; Fröhlich, D; Rothe, G; Prasser, C; Drobnik, W; Taeger, K; Meier-Hellmann, A; Reinhart, K; Zimmermann, M; Schmitz, G

    2001-10-01

    In an open, uncontrolled pilot study, 5 men and 1 woman with suspected gram-negative sepsis were treated with a new whole-blood endotoxin adsorption system. Lipopolysaccharide (LPS) adsorption was carried out by hemoperfusion over high-affinity polymethacrylate-bound albumin (Fresenius Endotoxin Adsorber EN 500). All patients suffered from endotoxemia (>20 pg/ml LAL) and met at least two systemic inflammatory response syndrome (SIRS) criteria. Four patients suffered from pneumonia due to mechanical ventilation, one from peritonitis, and one from pneumonia and peritonitis. Endotoxin adsorption was very well tolerated, and efficient LPS removal was shown in all patients. Apache II score immediately before immunoadsorption was 23.5 and was 22.3 after the last treatment. All 6 critically ill patients improved substantially and were discharged from the intensive care unit. LPS whole blood immunoadsorption is a promising new method. No side effects have been observed thus far. A large controlled study to prove clinical efficacy in patients with severe sepsis is under way. PMID:11778916

  3. 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)

    Mehdi Jahangiri

    2013-01-01

    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.

  4. Low Pressure Adsorbent for Recovery & Storage Vented Hydrogen Project

    National Aeronautics and Space Administration — A high performance fullerene-based adsorbent is proposed for recovery and storage hydrogen and separating helium via pressure-swing-adsorption (PSA) process....

  5. Atomic scale friction of molecular adsorbates during diffusion

    CERN Document Server

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

    2013-01-01

    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.

  6. Behavior of 137Cs in the water-adsorbent systems

    International Nuclear Information System (INIS)

    The 137Cs adsorption rate by adsorbents in the water increased with the time and it reached balance after 3h. The saturate values of adsorption rate were different with various adsorbents tested. Among them, zeolite, molecular sieve and montmorillonite were strong adsorbents to 137Cs, however, farinose clay, sandy loam 10 cm and clay loam 10 cm were cheap and available purification agents for 137Cs. The activation treatment improved adsorption ability of minerals to 137Cs. There was a power regression between the mineral size and the adsorption rate. Selecting suitable size might obtain an ideal effect of adsorption. Potassium ion inhibited the adsorption to 137Cs in the water body by adsorbents because of antagonism. The migration of 137Cs was very slow in the soil and 99% of 137Cs was concentrated in the surface soil (0-5 cm)

  7. 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)

  8. Adsorption of remazol brilliant blue on an orange peel adsorbent

    Scientific Electronic Library Online (English)

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

    2013-09-01

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

  9. Effect of adsorbed polymers on bubble--particle attachment.

    Science.gov (United States)

    Beaussart, Audrey; Parkinson, Luke; Mierczynska-Vasilev, Agnieszka; Ralston, John; Beattie, David A

    2009-12-01

    The influence of adsorbed dextrin-based polymers on the attachment of a rising air bubble to a talc surface has been investigated. Liquid film rupture and dynamic contact angle studies have highlighted the major role that adsorbed polymers can play in bubble-particle attachment. No direct link was established between the equilibrium contact angle of polymer-treated talc surfaces and talc flotation recovery. However, clear correlations were observed between the flotation recovery of polymer-treated talc and the measured wetting film rupture time and rate of dewetting for a bubble attaching to a talc basal plane surface treated with the polymers. The retardation of the three-phase contact line expansion caused by the adsorbed polymers was found to have the largest influence on the bubble-particle attachment. The effect of the morphology (coverage, distribution, and shape) of the adsorbed layer on the wetting film rupture and the motion of the receding water front is discussed. PMID:19860372

  10. Spectroelectrochemical studies of metallophthalocyanines adsorbed on electrode surfaces

    Energy Technology Data Exchange (ETDEWEB)

    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

    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.

  11. Development of novel adsorbents for environmental cleaning by radiation

    International Nuclear Information System (INIS)

    In order to improve our amenity spaces, the demand of non-odorous atmosphere is needed. Toxic gases such as trimethylamine and ammonia have been treated as the pollutant of the atmosphere. The development of an excellent and effective adsorbent for the toxic gases has been performed here and there all over the world. However, the development of the adsorbent with the consideration for conservation of environment must be made as one of the requisites. Therefore, we proposed the use of radiation for the preparation of toxic-gas-adsorbing materials. On the other hand, in our daily life, the large amount of calcium and magnesium contained in our drinking water has hindered the removal of a trace amount of pollutant such as lead. As a result, the development of the metal-ion-adsorbing material is very indispensable indeed. (J.P.N.)

  12. Electronic structure of benzene adsorbed on Ni and Cu surfaces

    Energy Technology Data Exchange (ETDEWEB)

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

    1997-04-01

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

  13. Theoretical atomic-force-microscopy study of adsorbed fullerene molecules

    Science.gov (United States)

    Girard, C.; Bouju, X.; Martin, O. J. F.; Dereux, A.; Chavy, C.; Tang, H.; Joachim, C.

    1993-11-01

    The capability of atomic-force microscopy (AFM) to localize both individual adsorbates and aggregates of adsorbed molecules was demonstrated a few years ago. More recently submonolayers of fullerene molecules deposited on a gold substrate have been imaged using such devices. In this paper, simulations of the atomic force between a thin probe tip and a set of adsorbed molecules is presented. The long-range part of the interaction is determined from a whole self-consistent procedure in which many-body effects are accounted for at all orders. In this description the probe tip interacts with the molecules and the surface through many-body dispersion forces. Short-range interactions are then included by using an atom-atom semiempirical pairwise potential. Simulations of AFM images of C60 adsorbed molecules are presented in two different modes of imaging: the constant-tip-height mode and the constant-force mode.

  14. TESTING OF CARBONACEOUS ADSORBENTS FOR REMOVAL OF POLLUTANTS FROM WATER

    Directory of Open Access Journals (Sweden)

    RAISA NASTAS

    2012-03-01

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

  15. Photoreactions of organic compounds adsorbed on zeolites

    International Nuclear Information System (INIS)

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

  16. Thermo-responsive adsorbent for size-selective protein adsorption.

    Science.gov (United States)

    Lee, Micky Fu Xiang; Chan, Eng Seng; Tam, Kam Chiu; Tey, Beng Ti

    2015-05-15

    A thermo-responsive random copolymer, POEGMA (poly(oligoethylene glycol) methacrylate) grafted on cationized agarose adsorbent was used for size selective protein adsorption. The effects of OEGMA300 ((oligoethylene glycol) methyl ether methacrylate, Mn=300g/mol) content and temperature on the adsorption of bovine serum albumin (BSA) were evaluated. Increasing the content of OEGMA300 resulted a reduction in BSA adsorption due to the enhanced shielding effect of OEGMA300 chains. Grafting of POEGMA chains onto cationized agarose adsorbent reduced the BSA adsorption by more than 95% at 26.5°C, which is below the LCST (lower critical solution temperature) of POEGMA. The BSA adsorption capacities for adsorbents grafted with 10 and 20mol% of OEGMA300 decreased by 48% and 46% respectively at 38°C, a temperature higher than their LCSTs. The temperature-dependent adsorption of BSA on the adsorbents was attributed to changes in the polymer conformation. The thermal transition of grafted POEGMA conformation exposed the ligand when the temperature was increased. Myoglobin (Myo), which was smaller than BSA, its adsorption behavior was less dependent on the polymer conformation. The adsorption of myoglobin onto the adsorbent with and without POEGMA showed similar percentage of reduction whereas the adsorption of BSA onto the adsorbent with POEGMA decreased by 7.6 times compared to the one without POEGMA. The packed bed of POEGMA grafted adsorbent was used for flow through separation of a protein mixture consisted of virus-like particle, Hepatitis B virus-like particle (HBVLP), BSA and insulin aspart. The recovery of HBVLP in 20mol% of OEGMA300 grafted adsorbent was increased by 19% compared to ungrafted adsorbent. The flow through of BSA can be reduced by increasing the operating temperature above LCST of 20mol% of OEGMA300 while the smaller protein, insulin aspart, remained adsorbed onto the cationized surface. Hence, this thermo-responsive adsorbent has a potential for size-selective separation of protein especially for the recovery of large biomolecule. PMID:25836051

  17. Kenaf Core as CO2 Adsorbent

    OpenAIRE

    Zaini, N.; Kamarudin, K. S. N.

    2014-01-01

    Kenaf is a green engineering material that has a great potential to be used as CO2 adsorbent. To enhance the capability of kenaf core as CO2 adsorbent, it should be cleaned and modified via various kinds of treatments. Prior to treatment process, the sample should be cleaned to remove all the adherent extraneous matters. In this study, kenaf core sample has been cleaned by using different types of cleaning methods such as using distilled water at room and b...

  18. Simulations of the Static Friction Due to Adsorbed Molecules

    OpenAIRE

    He, Gang; Robbins, Mark O.

    2001-01-01

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

  19. Simulations of the kinetic friction due to adsorbed surface layers

    OpenAIRE

    He, Gang; Robbins, Mark O.

    2000-01-01

    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 ...

  20. Electrochemical Studies of Paraquat Adsorbed onto Crystalline Apatite

    OpenAIRE

    El Mhammedi, Moulay Abderrahim; Chtaini, Abdelilah

    2007-01-01

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

  1. Some observations on the development of superior photocatalytic systems for application to water purification by the "adsorb and shuttle" or the interphase charge transfer mechanisms.

    Science.gov (United States)

    Langford, Cooper; Izadifard, Maryam; Radwan, Emad; Achari, Gopal

    2014-01-01

    Adsorb and shuttle (A/S) and interfacial charge transfer are the two major strategies for overcoming recombination in photocatalysis in this era of nanoparticle composites. Their relationships are considered here. A review of key literature is accompanied by a presentation of three new experiments within the overall aim of assessing the relation of these strategies. The cases presented include: A/S by a high silica zeolite/TiO2 composite, charge transfer (CT) between phases in a TiO2/WO3 composite and both A/S and CT by composites of TiO2 with powered activated carbon (AC) and single-walled carbon nanotubes (SWCNT). The opportunities presented by the two strategies for moving toward photocatalysts that could support applications for the removal of contaminants from drinking water or that lead to a practical adsorbent for organics that could be regenerated photocatalytically link this discussion to ongoing research here. PMID:25432008

  2. Some Observations on the Development of Superior Photocatalytic Systems for Application to Water Purification by the “Adsorb and Shuttle” or the Interphase Charge Transfer Mechanisms

    Directory of Open Access Journals (Sweden)

    Cooper Langford

    2014-11-01

    Full Text Available Adsorb and shuttle (A/S and interfacial charge transfer are the two major strategies for overcoming recombination in photocatalysis in this era of nanoparticle composites. Their relationships are considered here. A review of key literature is accompanied by a presentation of three new experiments within the overall aim of assessing the relation of these strategies. The cases presented include: A/S by a high silica zeolite/TiO2 composite, charge transfer (CT between phases in a TiO2/WO3 composite and both A/S and CT by composites of TiO2 with powered activated carbon (AC and single-walled carbon nanotubes (SWCNT. The opportunities presented by the two strategies for moving toward photocatalysts that could support applications for the removal of contaminants from drinking water or that lead to a practical adsorbent for organics that could be regenerated photocatalytically link this discussion to ongoing research here.

  3. 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.

  4. Gold recovery from low concentrations using nanoporous silica adsorbent

    Science.gov (United States)

    Aledresse, Adil

    The development of high capacity adsorbents with uniform porosity denoted 5%MP-HMS (5% Mercaptopropyl-Hexagonal Mesoporous Structure) to extract gold from noncyanide solutions is presented. The preliminary studies from laboratory simulated noncyanide gold solutions show that the adsorption capacities of these materials are among the highest reported. The high adsorption saturation level of these materials, up to 1.9 mmol/g (37% of the adsorbent weight) from gold chloride solutions (potassium tetrachloroaurate) and 2.9 mmol/g (57% of the adsorbent weight) from gold bromide solutions (potassium tetrabromoaurate) at pH = 2, is a noteworthy feature of these materials. This gold loading from [AuC4]- and [AuBr4 ]- solutions corresponds to a relative Au:S molar ratio of 2.5:1 and 3.8:1, respectively. These rates are significantly higher than the usual 1:1 (Au:S) ratio expected for metal ion binding with the material. The additional gold ions loaded have been spontaneously reduced to metallic gold in the mesoporous material. Experimental studies indicated high maximum adsorptions of gold as high as 99.9% recovery. Another promising attribute of these materials is their favourable adsorption kinetics. The MP-HMS reaches equilibrium (saturation) in less than 1 minute of exposure in gold bromide and less than 10 minutes in gold chloride. The MP-HMS materials adsorption is significantly improved by agitation and the adsorption capacity of Au (III) ions increases with the decrease in pH. The recovery of adsorbed gold and the regeneration of spent adsorbent were investigated for MP-HMS adsorbent. The regenerated adsorbent (MP-HMS) maintained its adsorption capacity even after repeated use and all the gold was successfully recovered from the spent adsorbent. For the fist time, a promising adsorbent system has been found that is capable of effectively concentrating gold thiosulphate complexes, whereas conventional carbon-inpulp (CIP) and carbon-in-leach (CIL) systems fail. The 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.

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

    DEFF Research Database (Denmark)

    Lausche, Adam C.; Medford, Andrew J.

    2013-01-01

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

  6. Mixed composition materials suitable for vacuum web sputter coating

    Science.gov (United States)

    Banks, Bruce A.; Rutledge, Sharon K.; Dever, Joyce A.; Bruckner, Eric J.; Walters, Patricia; Hambourger, Paul D.

    1996-01-01

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

  7. Efforts to Consolidate Chalcogels with Adsorbed Iodine

    Energy Technology Data Exchange (ETDEWEB)

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

    2013-08-28

    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.

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

    CERN Document Server

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

    2007-01-01

    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.

  9. Adsorbate-adsorbate interactions at electrochemical interfaces: S/Cu(001) in HCl solution

    Energy Technology Data Exchange (ETDEWEB)

    Taranovskyy, Andriy; Tansel, Tunay; Magnussen, Olaf [Institut fuer Experimentelle und Angewandte Physik, Universitaet Kiel, D-24098 Kiel (Germany)

    2008-07-01

    Following up our previous high-speed scanning tunneling microscopy study of sulfide tracer diffusion on Cu(001) in 0.01M HCl solution, we here present an analysis of the mutual motion of sulfide dimers in this system at room temperature. From the experimental video data histograms of the changes of the atomic configurations in subsequent frames were obtained. By fitting those to a theoretical model of dimer motion, based on solution of master equations, the hopping rates of S{sub a}d in the presence of a neighboring S{sub a}d were extracted. The pair interaction potential obtained from these rates shows an oscillatory distance dependence indicating anisotropic interactions. Also an influence of the electrode potential on the adsorbate interactions was observed.

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

    International Nuclear Information System (INIS)

    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.

  11. Lipid monolayers and adsorbed polyelectrolytes with different degrees of polymerization.

    Science.gov (United States)

    Ortmann, Thomas; Ahrens, Heiko; Lawrenz, Frank; Gröning, Andreas; Nestler, Peter; Günther, Jens-Uwe; Helm, Christiane A

    2014-06-17

    Polystyrene sulfonate (PSS) of different molecular weight M(w) is adsorbed to oppositely charged DODAB monolayers from dilute solutions (0.01 mmol/L). PSS adsorbs flatly in a lamellar manner, as is shown by X-ray reflectivity and grazing incidence diffraction (exception: PSS with M(w) below 7 kDa adsorbs flatly disordered to the liquid expanded phase). The surface coverage and the separation of the PSS chains are independent of PSS M(w). On monolayer compression, the surface charge density increases by a factor of 2, and the separation of the PSS chains decreases by the same factor. Isotherms show that on increase of PSS M(w) the transition pressure of the LE/LC (liquid expanded/liquid condensed) phase transition decreases. When the contour length exceeds the persistence length (21 nm), the transition pressure is low and constant. For low-M(w) PSS (<7 kDa) the LE/LC transition of the lipids and the disordered/ordered transition of adsorbed PSS occur simultaneously, leading to a maximum in the contour length dependence of the transition enthalpy. These findings show that lipid monolayers at the air/water interface are a suitable model substrate with adjustable surface charge density to study the equilibrium conformation of adsorbed polyelectrolytes as well as their interactions with a model membrane. PMID:24892967

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

    Science.gov (United States)

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

    2013-05-01

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

  13. Surface modification of chromatography adsorbents by low temperature low pressure plasma

    DEFF Research Database (Denmark)

    Arpanaei, Ayyoob; Winther-Jensen, BjØrn

    2010-01-01

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

  14. Silicon oxide coatings as protection against corrosion

    International Nuclear Information System (INIS)

    Silicon oxide films (SiOx (0x (xx to form protective SiO2. In the helium environment used, the rate of supply of oxygen was quite low. Stoichiometric SiO2 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.)

  15. Applications of Oxide Coatings in Photovoltaic Devices

    Directory of Open Access Journals (Sweden)

    Sonya Calnan

    2014-03-01

    Full Text Available Metalloid and metal based oxides are an almost unavoidable component in the majority of solar cell technologies used at the time of writing this review. Numerous studies have shown increases of ?1% absolute in solar cell efficiency by simply substituting a given layer in the material stack with an oxide. Depending on the stoichiometry and whether other elements are present, oxides can be used for the purpose of light management, passivation of electrical defects, photo-carrier generation, charge separation, and charge transport in a solar cell. In this review, the most commonly used oxides whose benefits for solar cells have been proven both in a laboratory and industrial environment are discussed. Additionally, developing trends in the use of oxides, as well as newer oxide materials, and deposition technologies for solar cells are reported.

  16. Plasma sprayed basalt/chromium oxide coatings.

    Czech Academy of Sciences Publication Activity Database

    Ageorges, H.; Medarhri, Z.; Ctibor, Pavel; Fauchais, P.

    2007-01-01

    Ro?. 11, ?. 1 (2007), s. 71-82. ISSN 1093-3611 Institutional research plan: CEZ:AV0Z20430508 Keywords : Chromia, basalt * plasma spraying * microstructure * phase analysis Subject RIV: JH - Ceramics, Fire-Resistant Materials and Glass Impact factor: 0.268, year: 2007

  17. Applications of Oxide Coatings in Photovoltaic Devices

    OpenAIRE

    Sonya Calnan

    2014-01-01

    Metalloid and metal based oxides are an almost unavoidable component in the majority of solar cell technologies used at the time of writing this review. Numerous studies have shown increases of ?1% absolute in solar cell efficiency by simply substituting a given layer in the material stack with an oxide. Depending on the stoichiometry and whether other elements are present, oxides can be used for the purpose of light management, passivation of electrical defects, photo-carrier generation, c...

  18. Mechanisms of the hydration of A-300 aerosol with adsorbed chlorides of alkali metals in an organic medium

    Science.gov (United States)

    Kravchenko, A. A.; Kuts, V. S.; Tsapko, M. D.; Krupskaya, T. V.; Turov, V. V.

    2015-05-01

    The hydration of systems obtained via the adsorption of alkali metal chlorides on A-300 nanosilica is studied by means of low-temperature 1H NMR spectroscopy. It is shown that in weakly polar organic media, adsorbed water is present in the form of weakly and strongly associated water. A reduction in the differentiation of adsorbed water in the SiO2/NaCl > SiO2/KCl > SiO2/LiCl series of composites is established that could be due to changes in the lattice parameters of SiO2. Quantum-chemical calculations are performed for the 1H NMR spectra of complexes containing clusters of Si8O12(OH)8 and hydrated ion pairs of alkali metal chlorides. These calculations allow us to explain the displacement in the chemical shifts of water protons.

  19. Effects of dispersed and adsorbed crude oil on microalgal and bacterial communities of cold seawater.

    Science.gov (United States)

    Siron, R; Pelletier, E; Roy, S

    1996-08-01

    : Mesocosm facilities consisting of five 3.5 m(3) stainless steel tanks filled with seawater from the St Lawrence Estuary (Québec, Canada) were used to conduct a 2 month experiment under the natural conditions prevailing at the end of the winter in subarctic environments, with seawater temperatures ranging from-1.5°C (surface ice cover) to 3°C. Various oil treatments were simulated in mesocosms: Forties crude oil was chemically dispersed, adsorbed onto an immersed substrate and spilled without any treatment. Total oil concentrations ranged from oil) to 44.6 mgl(-1) (dispersed oil). Contrasting with the parent crude oil and dispersed oil, the dissolved phase was enriched with low molecular weight polycyclic aromatic hydrocarbons (PAH). As revealed by pH variations, chlorophyll a contents and degraded pigments, the phytoplankton growth was inhibited early in tanks contaminated with dispersed and adsorbed oil. Although global measurements showed a recovery of the microalgal activity while the dispersed oil was diluted in a flow-through cascade system, the specific composition was quite different from the control, with an increase in small microflagellate species and a marked decline in the diversity of centric diatoms. Small microflagellates also dominated in the heavily oil-contaminated surface microlayer. The growth of viable heterotrophic bacteria (VHB) was immediately stimulated by both dispersed and adsorbed oil (10(4)-10(5) colony forming units per ml) and oil-degrading bacteria (ODB) reached maximum densities (10(2) CFU ml(-1)) later in the experiment. The adaptation of the indigenous community was assessed using the ODB/VHB ratio, which increased by ten times in the seawater contaminated with dispersed oil. No significant bacterial enhancement was observed in the tank that received untreated oil. No bacterial enrichment was found in the surface microlayer. In sediment traps, the bacterial density increased with the amount of total settling matter and oil residues. PMID:24193814

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

    International Nuclear Information System (INIS)

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

  1. 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)

  2. Current induced forces upon atoms adsorbed on conducting carbon nanotubes

    CERN Document Server

    Mingo, N; Han, J; Yang, Liu; Han, Jie

    2001-01-01

    We calculate the forces acting upon species adsorbed on a single wall carbon nanotube, in the presence of electric currents. We present a self consistent real space Green function method, which enables us to calculate the current induced forces from an ab-initio Hamiltonian. The method is applied to calculate the force on an adsorbed O atom on a (5,5) carbon nanotube, for different bias voltages and adsorption sites. For good contact regimes and biases of the order of Volts, the presence of a current can affect the potential energy surfaces considerably. Implications of these effects for the induced diffusion of the species are analyzed. The dependence of the force with the nanotube radius is studied. In addition, the magnitude of inelastic electron scattering, inducing vibrational heating, and its influence on the adsorbates' drift, is commented.

  3. Structure of adsorbed surfactants and polymers studies by neutron reflection

    International Nuclear Information System (INIS)

    Full text: The adsorption of surfactants depends on the chemical nature of the interface as well as the physical and chemical properties of the adsorbate. In this talk the structure of adsorbed layers of non-ionic surfactants on a variety of solid surfaces will be described and characterised by neutron reflection. The substrates include silica, grafted hydrocarbons, alcohols and acids. Further work has explored a range of adsorbates on spun-coated polystyrene films. Recent work looked at co-adsorption of a biopolymer (gelatine) and surfactants. A semi-empirical model to describe the changes in gelatine layers with pH will be presented. The co-adsorption of gelatine and ionic surfactants will also be described

  4. Experimental characterization of adsorbed protein orientation, conformation, and bioactivity.

    Science.gov (United States)

    Thyparambil, Aby A; Wei, Yang; Latour, Robert A

    2015-01-01

    Protein adsorption on material surfaces is a common phenomenon that is of critical importance in many biotechnological applications. The structure and function of adsorbed proteins are tightly interrelated and play a key role in the communication and interaction of the adsorbed proteins with the surrounding environment. Because the bioactive state of a protein on a surface is a function of the orientation, conformation, and accessibility of its bioactive site(s), the isolated determination of just one or two of these factors will typically not be sufficient to understand the structure-function relationships of the adsorbed layer. Rather a combination of methods is needed to address each of these factors in a synergistic manner to provide a complementary dataset to characterize and understand the bioactive state of adsorbed protein. Over the past several years, the authors have focused on the development of such a set of complementary methods to address this need. These methods include adsorbed-state circular dichroism spectropolarimetry to determine adsorption-induced changes in protein secondary structure, amino-acid labeling/mass spectrometry to assess adsorbed protein orientation and tertiary structure by monitoring adsorption-induced changes in residue solvent accessibility, and bioactivity assays to assess adsorption-induced changes in protein bioactivity. In this paper, the authors describe the methods that they have developed and/or adapted for each of these assays. The authors then provide an example of their application to characterize how adsorption-induced changes in protein structure influence the enzymatic activity of hen egg-white lysozyme on fused silica glass, high density polyethylene, and poly(methyl-methacrylate) as a set of model systems. PMID:25708632

  5. A new adsorbent for boron removal from aqueous solutions.

    Science.gov (United States)

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

    2013-01-01

    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

  6. Structure and dynamics of highly adsorbed semiflexible polymer melts

    Science.gov (United States)

    Carrillo, Jan-Michael; Cheng, Shiwang; Kumar, Rajeev; Goswami, Monojoy; Sokolov, Alexie; Sumpter, Bobby

    2015-03-01

    We present a detailed analysis of coarse-grained molecular dynamics simulations of melts of semi-flexible polymer chains in the presence of an adsorbing substrate. For polymer chains located far from the substrate the chain conformations follow the worm-like chain model, in contrast to the reflected Gaussian conformation near the substrate. This is demonstrated in the chain center-of-mass distribution normal to the substrate and the probability of a polymer chain ends to be the closest to the substrate. Both quantities agree with Silberberg's derivation for an ideal chain in the presence of a reflecting wall. We characterized the adsorbed chains and counted the number of loops and tails. For stiff chains, a tail and an adsorbed segment dominate the chain conformation of the adsorbed layer. Also, the mean-square end-to-end distance normal to the substrate is proportional to the normal component of the mean-square end-to-end distance of the tails. The tails do not follow the worm-like chain model and exhibit a stretched conformation. This picture for the adsorbed layer is akin to the ``polydisperse pseudobrush'' envisioned by Guiselin. We probe the dynamics of the segments by calculating the layer (z-)resolved intermediate coherent collective dynamics structure factor, S(q,t,z), for q values equivalent to the bond length. The segment dynamics is slower for stiffer chains. In the adsorbed layer, dynamics is slowed down and can be described by two relaxation times. Department of Energy, Office of Science DE-AC05-00OR227.

  7. Surface characterization of adsorbed asphaltene on a stainless steel surface

    International Nuclear Information System (INIS)

    X-ray photoelectron spectroscopy was used to characterize a single layer of adsorbed asphaltene on a metallic surface. The deposits were created by immersing a stainless steel disc into a dilute asphaltene solution with either toluene or dichloromethane as the solvent, although the toluene solution allowed for better control of the adsorbed asphaltene layer and less atmospheric oxygen contamination. The analyses for C 1s, S 2p3/2, N 1s and O 1s photoemission peaks indicated that different functional groups are present in the asphaltene layer including carboxylic, pyrrolic, pyridininc, thiophenic and sulfite, with slight differences in their binding energies

  8. High-performances carbonaceous adsorbents for hydrogen storage

    OpenAIRE

    Zhao, Weigang; Fierro, V.; Aylo?n Marquina, Elvira; Izquierdo Pantoja, Mari?a Teresa; Celzard, A.

    2013-01-01

    Activated carbons (ACs) with controlled microporosity have been prepared and their H 2 storage performances have been tested in a gravimetric device. Such adsorbents are natural Chinese anthracites chemically activated with alkaline hydroxides, NaOH or KOH. Outstanding total storage capacities of hydrogen, as high as 6.6wt.% equivalent to excess capacity of 6.2 wt.%, have been obtained at 4MPa for some of these adsorbents. These values of hydrogen adsorption are among the best, if not the hig...

  9. 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)

  10. Electrochemical Studies of Paraquat Adsorbed onto Crystalline Apatite

    Directory of Open Access Journals (Sweden)

    Moulay Abderrahim EL MHAMMEDI

    2007-09-01

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

  11. 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.

  12. Ion-exchange properties of microporous tungstates: novel adsorbents for nuclear waste management applications

    International Nuclear Information System (INIS)

    A hydrothermally prepared tungsten oxide-based phase, ATS-1 (ANSTO Tungstate Sorbent), of nominal composition, Na0.3Mo0.1W0.9O3.?H2O, has been shown to display promising selectivity for both Cs+ and Sr2+ cations from acidic simulant, indicative of the Intermediate Level Liquid Waste (ILLW) produced from 99Mo radioisotope production at the ANSTO site. The development of an inorganic ion-exchanger that displays such selectivity for both Cs+ and Sr2+ in acidic solutions has previously eluded researchers in the field of inorganic ion-exchangers. The ATS-1 adsorbent also displays exquisite selectivity for lead (and polonium) in low to high acidity solutions, and as such is being further investigated as a method to reduce the radiological hazard from 210Pb and 210Po during the processing of uranium ore bodies. The adsorption of Cs+, Sr2+ and Pb2+ cations by ATS-1 has been extensively investigated with respect to the kinetics of adsorption, capacity and the effect of competing cations viz. Na+, K+. The ATS-1 adsorbent has also been successfully granulated with an inert, organic matrix, which has consequently allowed the study of cation adsorption using more application-based, column separations. The results of these investigations suggest that these materials have potential application in several nuclear waste management issues in Australia at the present

  13. Alkali-induced nanopatterning of Ag(110) surface mediated by molecular adsorbate

    Energy Technology Data Exchange (ETDEWEB)

    Mercurio, Giuseppe; Willenbockel, Martin; Weiss, Christian; Temirov, Ruslan; Subach, Sergey; Tautz, Stefan [Peter Gruenberg Institut (PGI-3), Forschungszentrum Juelich, 52425 Juelich (Germany); JARA-Fundamentals of Future Information Technology (Germany); Bauer, Oliver; Fiedler, Benjamin; Sokolowski, Moritz [Institute for Physical and Theoretical Chemistry, University of Bonn (Germany)

    2011-07-01

    It is known for decades that alkali metals initiate the restructuring of fcc metal surfaces resulting in a composite patterned morphology. On the other hand, co-adsorbed metal atoms and organic molecules often form extended 2D networks due to the metal-molecular coordination reaction. Here we report on a new type of structural modification of the molecule-substrate interface, which is not only restricted to self-assembly of the adsorbed metal atoms and molecules, but it also involves significant morphological reorganization of the metallic surface. In the experiments, potassium atoms are deposited on a monolayer of the long-range ordered PTCDA/Ag(110) phase. Subsequent annealing forces potassium atoms to intercalate under the molecular layer partially unbinding PTCDA from the substrate. The complex interaction between potassium, PTCDA and substrate induces a significant silver mass-transfer and leads to the appearance of 1D stripe-structures of K atoms and PTCDA molecules on a nanopatterned silver surface. Structural and electronic properties of this pattern were studied by means of NIXSW, XPS, LEED and LT-STM.

  14. Cell adhesion to biomaterials: correlations between surface charge, surface roughness, adsorbed protein, and cell morphology.

    Science.gov (United States)

    Hallab, N J; Bundy, K J; O'Connor, K; Clark, R; Moses, R L

    1995-01-01

    Adhesion of cells to a biomaterial surface can be a major factor mediating its biocompatibility. In this investigation, jet impingement techniques were used to quantify strength of cellular adhesion to various material surfaces. The metals tested: HS25 (a cobalt-based alloy similar to F75), 316L stainless steel, Ti-6Al-4V, and commercially pure tantalum, exhibited nearly a fivefold increase in adhesion strength above that characteristic of the polymeric materials tested (PTFE, silicone rubber, and HDPE). The present study examines physical and biological factors that might influence fibroblast adhesion to the biomaterial surface. The relation between surface charge and cellular adhesion was investigated in a controlled manner by measuring adhesion strength over a range of charge densities. The cells showed charge and electrical potential-dependent adhesion maxima, suggesting that surface alloying for optimum adherence may be possible. In a preliminary series of experiments adsorbed serum protein layers on a series of materials of differing adherence were investigated using gel electrophoresis to assess protein composition. Analysis of adsorbed proteins revealed little difference in relative abundance or total adsorption quantity. SEM micrographs of cells on Ti-6Al-4V and silicone rubber (high and low adhesion materials, respectively) demonstrated differences in cell morphology and cell density. PMID:10172729

  15. WO x , SiO2, TiO2/Ti composites, fabricated by means of plasma electrolytic oxidation, as catalysts of ethanol dehydration into ethylene

    Science.gov (United States)

    Vasilyeva, M. S.; Rudnev, V. S.; Tulush, A. I.; Nedozorov, P. M.; Ustinov, A. Yu.

    2015-06-01

    WO3, SiO2, TiO2/Ti composites are fabricated and studied by means of X-ray diffraction analysis and X-ray photoelectron and IR spectroscopy. It is established that the surface of an oxide coating contains up to 2% of tungsten in the composition of WO3, SiO2, and TiO2, along with carbon compounds. Data on the catalytic activity of SiO2, TiO2/Ti and WO3, SiO2, TiO2/Ti composites in ethanol dehydration are obtained. In the case of WO3, SiO2, TiO2/Ti composites, the degree of conversion and the selectivity of ethanol transformation into ethylene at 480°C reaches 97%.

  16. Alpha spectrometry sample preparation using selectively adsorbing thin films

    Science.gov (United States)

    Surbeck

    2000-07-01

    Several years ago, Switzerland introduced limits for natural radionuclides in food, e.g. 1 Bq/l for 226Ra or 10 Bq/l for the sum of 238U and 234U in drinking water. To make enforcement by regional (cantonal) laboratories more attractive, simplified analytical methods had to be offered, at least for drinking water. A first step has been the development of radium adsorbing sheets. A 20 mm x 20 mm MnO2 film on a polyamide substrate adsorbs more than 80% of the radium present in a 100 ml water sample within 6 h. The film is thin enough to allow for high resolution alpha spectrometry. A second step now under way is to produce thin films, which selectively adsorb uranium. Actually, an ion exchange resin with diphosphonic and sulfonic acid groups is used for this purpose. Although not yet very thin, these films make possible energy resolutions far better than with any liquid scintillation alpha spectrometry method. Adsorption efficiencies are more than 80% after 20 h exposition to a 100 ml water sample (20 mm x 20 mm sheet). A third step is to have a system that measures radionuclide concentrations in water on-line. A prototype is presented where radionuclides are adsorbed on a film in contact with the water. A Si-detector placed on the other side of the film support counts the alphas passing through. PMID:10879845

  17. ?SR investigation of ethyl radicals adsorbed on silica

    International Nuclear Information System (INIS)

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

  18. The density and refractive index of adsorbing protein layers.

    Science.gov (United States)

    Vörös, Janos

    2004-07-01

    The structure of the adsorbing layers of native and denatured proteins (fibrinogen, gamma-immunoglobulin, albumin, and lysozyme) was studied on hydrophilic TiO(2) 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 refractive index changes during the protein-adsorption process indicated the presence of conformational changes (e.g., partial unfolding) in general, especially upon contact with the hydrophobic surface. The structure of the formed layers was found to depend on the size of the proteins and on the experimental conditions. On the TiO(2) surface smaller proteins formed a denser layer than larger ones and the layer of unfolded proteins was less dense than that adsorbed from the native conformation. The hydrophobic surface induced denaturation and resulted in the formation of thin compact protein films of albumin and lysozyme. A linear correlation was found between the quartz crystal microbalance measured dissipation factor and the total water content of the layer, suggesting the existence of a dissipative process that is related to the solvent molecules present inside the adsorbed protein layer. Our measurements indicated that water and solvent molecules not only influence the 3D structure of proteins in solution but also play a crucial role in their adsorption onto surfaces. PMID:15240488

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

    Energy Technology Data Exchange (ETDEWEB)

    Hwang, Kevin Shao-Lin

    2003-05-23

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

  20. Natural material adsorbed onto a polymer to enhance immune function

    Directory of Open Access Journals (Sweden)

    Reinaque AP

    2012-08-01

    Full Text Available Ana Paula Barcelos Reinaque,1 Eduardo Luzía França,2 Edson Fredulin Scherer,3 Mayra Aparecida Côrtes,1 Francisco José Dutra Souto,4 Adenilda Cristina Honorio-França51Post Graduate Program in Material Science, 2Institute of Biological and Health Science, Federal University of Mato Grosso, Barra do Garças, 3Post Graduate Program in Material Science, Institute of Biological and Health Science, Federal University of Mato Grosso, Pontal do Araguaia, 4Faculty of Medical Sciences, Federal University of Mato Grosso, Cuiabá, 5Institute of Biological and Health Science, Federal University of Mato Grosso, Pontal do Araguaia, MT, BrazilBackground: In this study, we produced poly(ethylene glycol (PEG microspheres of different sizes and adsorbing a medicinal plant mixture, and verified their effect in vitro on the viability, superoxide production, and bactericidal activity of phagocytes in the blood.Methods: The medicinal plant mixture was adsorbed onto PEG microspheres and its effects were evaluated by flow cytometry and fluorescence microscopy.Results: Adsorption of the herbal mixture onto the PEG microspheres was achieved and the particles were internalized by phagocytes. PEG microspheres bearing the adsorbed herbal mixture stimulated superoxide release, and activated scavenging and microbicidal activity in phagocytes. No differences in functional activity were observed when the phagocytes were not incubated with PEG microspheres bearing the adsorbed herbal mixture.Conclusion: This system may be useful for the delivery of a variety of medicinal plants and can confer additional protection against infection. The data reported here suggest that a polymer adsorbed with a natural product is a treatment alternative for enhancing immune function.Keywords: natural product, polymer, adsorption, immune function, phagocytes

  1. Desempenho do Stent Recoberto por Titânio-Óxido Nítrico em Pacientes com Doença Coronária Multiarterial / Performance of the Titanium-Nitride-Oxide Coated Stent in Patients with Multivessel Coronary Artery Disease

    Scientific Electronic Library Online (English)

    Thomas Edison Cintra, Osterne; Wilson Albino, Pimentel Filho; Fernando Augusto Molinori di Castro, Curado; Edson Alcides, Bocchi; Wellington Borges, Custódio; Gustavo Mello Gomes de, Matos; Pedro Henrique Luiggi, Teixeira; Marcos Venício Martins, Gori; Waigner Bento, Pupin Filho; Gustavo Vinicius Lambert, Olivotti; Jorge Roberto, Büchler; Stoessel Figueiredo de, Assis.

    2014-04-01

    Full Text Available Introdução: Até o momento, nenhum estudo avaliou o stent recoberto por titânio-óxido nítrico em pacientes com doença arterial coronariana multiarterial. Comparamos o desempenho do stent Titan-2® ao stents farmacológicos de segunda geração nesse cenário. Métodos: No período de 2011 a 2012, 284 pac [...] ientes foram tratados com o stent Titan-2®, dos quais 100 (35,2%) eram portadores de doença arterial coronariana multiarterial. Esse grupo foi comparado a 100 pacientes, de um grupo de 304 (38,9%), com doença arterial coronariana multiarterial, tratados com o stent farmacológico de segunda geração com polímeros duráveis ou biodegradáveis. O desfecho primário foi a ocorrência de eventos cardíacos adversos maiores em 1 ano. Resultados: Características clínicas, angiográficas e do procedimento não apresentaram diferenças entre os grupos. A maioria dos pacientes do grupo Titan-2® era do sexo masculino (70%), com idade de 68,4 ± 12,9 anos e 25% eram diabéticos. Predominaram os quadros clínicos estáveis (68%), 51% tinham acometimento triarterial e a função ventricular estava preservada. A incidência de eventos cardiovasculares adversos maiores em 1 ano no grupo Titan-2® foi de 21% (vs. 17%; p = 0,59), óbito ocorreu em 3% (vs. 2%; p > 0,99) dos pacientes, infarto do miocárdio em 5% (vs. 4%; p > 0,99) e nova revascularização miocárdica em 13% (vs. 11%; p = 0,83). Não foram constatadas tromboses de stent definitivas em nenhum grupo. Conclusões: O uso do Titan-2® apresentou resultados similares aos do stent farmacológico de segunda geração, o que o torna atrativo para ser utilizado no complexo cenário de pacientes portadores de doença arterial coronariana multiarterial. Abstract in english Background: To date, there are no studies evaluating the use of the titanium-nitride-oxide coated stent in patients with multivessel coronary artery disease. We have compared the performance of the Titan-2® stent to that of the second generation drug-eluting stents in this scenario. Methods: From [...] 2011 to 2012, 284 patients were treated with the Titan-2® stent, of which 100 (35.2%) had multivessel coronary artery disease. This group was compared to 100 patients, of a group of 304 (38.9%) patients with multivessel coronary artery disease treated with second generation drug-eluting stents with durable or biodegradable polymers. The primary endpoint was the occurrence of major adverse cardiovascular events at 1 year. Results: Clinical, angiographic and procedure-related characteristics of the patients did not show differences between groups. Most patients in the Titan-2® group were male (70%), mean age was 68.4 ± 12.9 years and 25% were diabetic. Stable symptomatic patients were prevalent (68%), 51% had three-vessel disease and ventricular function was preserved (55.6 ± 12.7%). The incidence of major adverse cardiovascular events at 1 year in the Titan-2® group was 21% (vs. 17%; p = 0.59), death was observed in 3% (vs. 2%; p > 0.99) of the patients, acute myocardial infarction in 5% (vs. 4%; p > 0.99) and a new revascularization procedure in 13% (vs. 11%; p = 0.83). Definitive stent thrombosis was not observed in either group. Conclusions: The Titan-2® stent showed similar results to those of the second-generation drug-eluting stents, which makes it attractive for use in the complex scenario of patients with multivessel coronary artery disease.

  2. NIST/ARPA-E Database of Novel and Emerging Adsorbent Materials - SRD 205

    National Institute of Standards and Technology, Department of Commerce — The NIST/ARPA-E Database of Novel and Emerging Adsorbent Materials is a free, web-based catalog of adsorbent materials and measured adsorption properties of...

  3. Interstitial and adsorbed phosphates in shelf sediments off Visakhapatnam, east coast of India

    Digital Repository Service at National Institute of Oceanography (India)

    Sarma, V.V; Raju, G.R.K.

    1991-01-01

    Spatial distribution of interstitial and adsorbed phosphates in the shelf sediments shows an increasing trend with distance from coastal to inshore region. Maximum concentration ranges of interstitial and adsorbed phosphates are 16-19 and 40-50 mu g...

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

    Science.gov (United States)

    Luckarift, Heather R; Sizemore, Susan R; Farrington, Karen E; Fulmer, Preston A; Biffinger, Justin C; Nadeau, Lloyd J; Johnson, Glenn R

    2011-01-01

    The natural attenuation of hydrocarbons can be hindered by their rapid dispersion in the environment and limited contact with bacteria capable of oxidizing hydrocarbons. A functionalized composite material is described herein, that combines in situ immobilized alkane-degrading bacteria with an adsorbent material that collects hydrocarbon substrates, and facilitates biodegradation by the immobilized bacterial population. Acinetobacter venetianus 2AW was isolated for its ability to utilize hydrophobic n-alkanes (C10-C18) as the sole carbon and energy source. Growth of strain 2AW also resulted in the production of a biosurfactant that aided in the dispersion of complex mixtures of hydrophobic compounds. Effective immobilization of strain 2AW to the surface of Ottimat™ adsorbent hair mats via vapor phase deposition of silica provided a stable and reproducible biocatalyst population that facilitates in situ biodegradation of n-alkanes. Silica-immobilized strain 2AW demonstrated ca. 85% removal of 1% (v/v) tetradecane and hexadecane within 24 h, under continuous flow conditions. The methodology for immobilizing whole bacterial cells at the surface of an adsorbent, for in situ degradation of hydrocarbons, has practical application in the bioremediation of oil in water emulsions. Published 2011 American Institute of Chemical Engineers Biotechnol Prog., 2011. PMID:21948333

  5. Spectroscopic study of the Eu(fod3 complex adsorbed on a 3-trimethoxypropylthioethylamine modified silica surface

    Directory of Open Access Journals (Sweden)

    GILBERTO F. DE SA

    2004-05-01

    Full Text Available By using 3-mercaptopropyltrimethoxysilane and ethylenediamine as precursors, the compound 3-trimethoxypropylhioethylamine was synthesized, and then used as a silylating agent to obrtain, through a sol-gel process, an organicmodification of a silica-gel sample. Asurface thus modified was used as a substrate for the adsorption of the luminescent Eu(fod3·2H2O complex. Eu(fod3·2H2O and the silicon hybrid were mixed in stoichiometric amounts to produce samples with 1 %, 5 % and 10 % (m/m of adsorbed complex. The adsorbed complex was then studied from the spectroscopic point of view. The lifetimes measured for the emission process are 476, 542 and 566 ms for 1 %, 5 % and 10 % samples, respectively. Furthermore, comparison with experimental data for n-[3(trimethoxysilyl propyl]-ethylenediamine modified silica gel surfaces emphasizes the prominenet role of the chemical composition of the silica modified surface on the spectroscopic properties of the adsorbed complex.

  6. Removal of alizarin red S (dye) from aqueous media by using alumina as an adsorbent

    International Nuclear Information System (INIS)

    Adsorption is potentially an attractive methodology for removing hazardous dyestuff and heavy metals from industrial effluents. In this work the removing efficiency of an industrially important dye Alizarin Red S from aqueous media using alumina as adsorbent has been investigated. Various parameters, which can influence the adsorption like, mesh size of adsorbent, contact time of solution with adsorbent, temperature, pH, adsorbent dose and stirring speed were optimized. (author)

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

    OpenAIRE

    Usenko, A. S.

    2013-01-01

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

  8. Measurement of the Mass and Rigidity of Adsorbates on a Microcantilever Sensor

    OpenAIRE

    Javier Tamayo; Zaballos, A; Johann Mertens; Montserrat Calleja; Daniel Ramos

    2007-01-01

    When microcantilevers are used in the dynamic mode, the resonance shift upon material adsorption depends on the position of the adsorbate along the microcantilever. We have previously described that the adsorbate stiffness needs to be considered in addition to its mass in order to correctly interpret the resonance shift. Here we describe a method that allows obtaining the Young's modulus of the adsorbed bacteria derived from the measurement of the frequency shift when adsorbates are placed cl...

  9. The Relationship between Platelet Adhesion on Surfaces and the Structure versus the Amount of Adsorbed Fibrinogen

    OpenAIRE

    Sivaraman, Balakrishnan; Latour, Robert A.

    2009-01-01

    While platelet adhesion to biomaterial surfaces is widely recognized to be related to adsorbed fibrinogen (Fg), it has remained controversial whether platelet adhesion is in response to the adsorbed amount or the adsorbed conformation of this protein. To address this issue, we designed a series of platelet adhesion studies to clearly separate these two factors, thus enabling us to definitively determine whether it is the amount or the conformation of adsorbed Fg that mediates platelet respons...

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

    International Nuclear Information System (INIS)

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

  11. Defluoridation of water via Light Weight Expanded Clay Aggregate (LECA): Adsorbent characterization, competing ions, chemical regeneration, equilibrium and kinetic modeling

    OpenAIRE

    Sepehr, Mohammad Noori; Kazemian, Hossein; Ghahramani, Esmail; Amrane, Abdeltif; Sivasankar, V.; Zarrabi, Mansur

    2014-01-01

    Natural, H2O2 and MgCl2 - modified Light Weight Expanded Clay Aggregate (LECA) were used as fluoride adsorbents. Characterization of LECA and its modified forms was done by infra-red, X-ray diffraction, scanning electron microscope and X-ray fluorescence studies. The specific surface area of HML and MGML was 3.34 and 3.97 times greater than that of NL (11.72 m2/g). Improved chemical composition of Magnesium (as oxide) to 15.6% by 2 M MgCl2 solution was ascertained through XRF results. The flu...

  12. Analysis of positron annihilation spectra and reemitted positrons from clean and hydrogen adsorbed Ni(111) surfaces

    International Nuclear Information System (INIS)

    The positron annihilation ?-ray spectra emitted from clean and hydrogen adsorbed Ni(111) surfaces are measured. We have discussed the disordered structures of adsorbed-hydrogens on Ni(111) surface studied by the positron annihilation spectra and reemitted slow positrons. The present experiments suggest the presence of the positronium hydride, PsH, on hydrogen-saturatedly adsorbed Ni(111) surface.

  13. Chitosan-cellulose composite materials: Preparation, Characterization and application for removal of microcystin

    Energy Technology Data Exchange (ETDEWEB)

    Tran, Chieu D., E-mail: chieu.tran@marquette.edu [Department of Chemistry, Marquette University, P.O. Box 1881, Milwaukee, WI 53201 (United States); Duri, Simon [Department of Chemistry, Marquette University, P.O. Box 1881, Milwaukee, WI 53201 (United States); Delneri, Ambra; Franko, Mladen [Laboratory for Environmental Research, University of Nova Gorica, Vipavska 13, 5001 Nova Gorica (Slovenia)

    2013-05-15

    Highlights: •A novel and recyclable synthetic method using an ionic liquid, a Green Solvent. •Ecocomposite materials were synthesized from cellulose (CEL) and chitosan (CS). •Adding CEL into CS substantially increases tensile strength of the composite. •The composite is much better adsorbent for cyanotoxins than other materials. •The composite can be reused because adsorbed microcystin can be desorbed. -- Abstract: We developed a simple and one-step method to prepare biocompatible composites from cellulose (CEL) and chitosan (CS). [BMIm{sup +}Cl{sup ?}], an ionic liquid (IL), was used as a green solvent to dissolve and prepare the [CEL + CS] composites. Since majority (>88%) of IL used was recovered for reuse by distilling the aqueous washings of [CEL + CS], the method is recyclable. XRD, FTIR, NIR, {sup 13}C CP-MAS-NMR and SEM were used to monitor the dissolution and to characterize the composites. The composite was found to have combined advantages of their components: superior mechanical strength (from CEL) and excellent adsorption capability for microcystin-LR, a deadly toxin produced by cyanobacteria (from CS). Specifically, the mechanical strength of the composites increased with CEL loading; e.g., up to 5× increase in tensile strength was achieved by adding 80% of CEL into CS. Kinetic results of adsorption confirm that unique properties of CS remain intact in the composite, i.e., it is not only a very good adsorbent for microcystin but also is better than all other available adsorbents. For example, it can adsorb 4× times more microcystin than the best reported adsorbent. Importantly, the microcystin adsorbed can be quantitatively desorbed to enable the composite to be reused with similar adsorption efficiency.

  14. Chitosan-cellulose composite materials: Preparation, Characterization and application for removal of microcystin

    International Nuclear Information System (INIS)

    Highlights: •A novel and recyclable synthetic method using an ionic liquid, a Green Solvent. •Ecocomposite materials were synthesized from cellulose (CEL) and chitosan (CS). •Adding CEL into CS substantially increases tensile strength of the composite. •The composite is much better adsorbent for cyanotoxins than other materials. •The composite can be reused because adsorbed microcystin can be desorbed. -- Abstract: We developed a simple and one-step method to prepare biocompatible composites from cellulose (CEL) and chitosan (CS). [BMIm+Cl?], an ionic liquid (IL), was used as a green solvent to dissolve and prepare the [CEL + CS] composites. Since majority (>88%) of IL used was recovered for reuse by distilling the aqueous washings of [CEL + CS], the method is recyclable. XRD, FTIR, NIR, 13C CP-MAS-NMR and SEM were used to monitor the dissolution and to characterize the composites. The composite was found to have combined advantages of their components: superior mechanical strength (from CEL) and excellent adsorption capability for microcystin-LR, a deadly toxin produced by cyanobacteria (from CS). Specifically, the mechanical strength of the composites increased with CEL loading; e.g., up to 5× increase in tensile strength was achieved by adding 80% of CEL into CS. Kinetic results of adsorption confirm that unique properties of CS remain intact in the composite, i.e., it is not only a very good adsorbent for microcystin but also is better than all other available adsorbents. For example, it can adsorb 4× times more microcystin than the best reported adsorbent. Importantly, the microcystin adsorbed can be quantitatively desorbed to enable the composite to be reused with similar adsorption efficiency

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

    Energy Technology Data Exchange (ETDEWEB)

    Nakai, Tomonori; Wakabayashi, Syunya; Mimura, Hitoshi; Niibori, Yuichi; Kurosaki, Fumio; Matsukura, Minoru [Dept. of Quantum Science and Energy Engineering, Graduate School of Engineering, Tohoku University,Aramaki-Aza-Aoba 6-6-01-2,Sendai, 980-8579 (Japan); Tanigawa, Hiroshi; Ishizaki, Eiji [UNION SHOWA K.K., 17-20, Mita 2-chome, Minato-ku, Tokyo 108-0073 (Japan)

    2013-07-01

    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{sup +} and Sr{sup 2+} As for Cs{sup +} adsorption, CST, chabazite and insoluble ferrocyanides composites had relatively large distribution coefficients (K{sub d}) above 10{sup 3} cm{sup 3}/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{sup +}-zeolites, suggesting high immobilization ability of zeolites for Cs{sup +}. As for Sr{sup 2+} adsorption, A and X zeolites had relatively large K{sub d} values around 10{sup 2} cm{sup 3}/g, and zeolite sheet (A zeolite) exhibited excellent adsorption kinetics in seawater. Considering the decontamination of radioactive Sr{sup 2+} in groundwater, the effects of Ca{sup 2+} and Mg{sup 2+} ions on the K{sub d} value of Sr{sup 2+} were further examined by batch method. The K{sub d} value of Sr{sup 2+} was almost independent of Mg{sup 2+} concentration up to 2,500 ppm, while gradually lowered in the presence of Ca{sup 2+} above 200 ppm, due to the differences in the ionic radius of hydrated ion. The Cs{sup +} and Sr{sup 2+} 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 Sr{sup 2+} and Cs{sup +}, respectively. The K{sub d} values of Sr{sup 2+} and Cs{sup +} in seawater were estimated to be above 10{sup 2} and 10{sup 3} cm{sup 3}/g, respectively, indicating the effectiveness for the decontamination of both Sr{sup 2+} and Cs{sup +}. The basic data on the Cs{sup +} and Sr{sup 2+} adsorption properties for selective adsorbents are effective for the practical decontamination processes of these metal ions in seawater and groundwater. (authors)

  16. Electron bombardment of water adsorbed on Zr(0001) surfaces

    International Nuclear Information System (INIS)

    A study of the effects of electron bombardment on water adsorbed on Zr(0001) is reported. Zirconium surfaces are dosed with isotopic water mixtures at 160 K followed by electron bombardment (485 eV). The system is then probed by low energy electron diffraction, temperature programmed desorption (TPD) and Auger electron spectroscopy (AES). No evidence is found that would indicate preferential mixing of hydrogen from the bulk with isotopic water dissociation products during TPD. However, electron bombardment results in the sharpening of a hydrogen/deuterium desorption peak near 320 K and the production of water near 730 K at low water exposures. In addition, although water does not oxidize Zr(0001) thermally, electron bombardment of adsorbed water induces a shift of about 2 eV in the Zr AES features indicating that the surface is partially oxidized by electron bombardment

  17. Nanocrystalline Akaganeite as Adsorbent for Surfactant Removal from Aqueous Solutions

    Directory of Open Access Journals (Sweden)

    Eleni A. Deliyanni

    2013-01-01

    Full Text Available The present study presents the effective use of nanocrystalline akaganeite for the adsorption of an anionic (SDS, a cationic (CTAB, and a nonionic (tween80 surfactant from wastewater. Equilibrium experiments, as well as thermodynamic analysis, were performed. The maximum SDS adsorption occurs at the lowest pH value (5, the opposite is observed for CTAB (pH = 11, while for tween80, the change of pH value did not affect the adsorption. The equilibrium data could be described by Freundlich and Langmuir isotherms. The maximum adsorption capacity at 25 °C (pH = 8 was 823.96 mg/g for SDS, 1007.93 mg/g for CTAB, and 699.03 mg/g for tween80. The thermodynamic parameters revealed the exothermic and spontaneity nature of the process. Also, FTIR measurements established that surfactants are adsorbed on the surface of akaganeite, replacing adsorbed water.

  18. Effect of adsorbed impurities on catalytic CO oxidation

    Directory of Open Access Journals (Sweden)

    I.S. Bzovska

    2009-01-01

    Full Text Available The effect of inactive adsorbed impurities on kinetics of catalytic synthesis of carbon dioxide is investigated in the framework of the lattice-gas model. Namely, two cases of equilibrium impurities with fast, compared with the reaction's rate, and slow self dynamics are analyzed. It is revealed that the adsorbed impurities shift the phase diagram to the region of lower temperatures and higher pressures pCO. In the case of slow impurities the bistable region is narrowed far more than in the case when their dynamics is fast and their distribution on the surface can be assumed to be equilibrium. The critical concentration of impurities at which the bistable region disappears, is found. From analysis of the kinetic equations the condition of the existence of the bifurcation region is analytically obtained.

  19. Determination of rates of radiation initiation of adsorbed monomers polymerization

    International Nuclear Information System (INIS)

    The rates of radiation initiation of radical polymerization v1 of vinylacetate and methyl methacrylate adsorbed on aerosil were determined by three various methods. At a monolayer packing on aerosil surface, v1 were found to be close for both monomers and constituted the value of (1.2+-1.3)x107 molecules/cm2 x s. On polymeriza, tion of vinylacetate on a methylated aerosil v1--(5.8,1.5)x107 molecules/cm2 x s. The dependences of v1 on the concentration of absorbed monomer and on temperature were studied. It was found that for a monolayer and lesser degrees of surface occupation the initiating active sites were formed predominantly due to irradiation energy absorbed by the adsorbent. Yields of polymers were found at various radiation doses

  20. Allantoin as a solid phase adsorbent for removing endotoxins.

    Science.gov (United States)

    Vagenende, Vincent; Ching, Tim-Jang; Chua, Rui-Jing; Gagnon, Pete

    2013-10-01

    In this study we present a simple and robust method for removing endotoxins from protein solutions by using crystals of the small-molecule compound 2,5-dioxo-4-imidazolidinyl urea (allantoin) as a solid phase adsorbent. Allantoin crystalline powder is added to a protein solution at supersaturated concentrations, endotoxins bind and undissolved allantoin crystals with bound endotoxins are removed by filtration or centrifugation. This method removes an average of 99.98% endotoxin for 20 test proteins. The average protein recovery is ?80%. Endotoxin binding is largely independent of pH, conductivity, reducing agent and various organic solvents. This is consistent with a hydrogen-bond based binding mechanism. Allantoin does not affect protein activity and stability, and the use of allantoin as a solid phase adsorbent provides better endotoxin removal than anion exchange, polymixin affinity and biological affinity methods for endotoxin clearance. PMID:24001944

  1. Effect of CO2 on a polystyrene adsorbed nanolayer

    Science.gov (United States)

    Barkley, Deborah; Jiang, Naisheng; Sendogdular, Levent; di, Xiaoyu; Sen, Mani; Endoh, Maya K.; Koga, Tadanori; Akgun, Bulent; Dimitriou, Michael; Satija, Sushil

    2015-03-01

    We report the role of compressed carbon dioxide (CO2) in a mobility gradient of polymer chains near a planar solid substrate. A series of bilayers of bottom hydrogenated polystyrene and top deuterated polystyrene layers were prepared on Si substrates, and high pressure neutron reflectivity (NR) was used to study diffusive motion at the polymer/polymer interface. The interdiffusion is hindered when the distance is less than 3Rg (Rg, radius of polymer gyration). This reduced chain diffusivity is attributed to CO2-induced polymer adsorption on the substrate, transforming the 0.6Rg thick region from the substrate interface into an irreversibly adsorbed polymer layer. The cohesion strength is attributed to loops in the adsorbed chains with which the neighboring chains can entangle. T. K. acknowledges the partial financial support from NSF Grants (CMMI-084626 and CMMI-1332499).

  2. Adsorbate-induced curvature and stiffening of graphene.

    Science.gov (United States)

    Svatek, Simon A; Scott, Oliver R; Rivett, Jasmine P H; Wright, Katherine; Baldoni, Matteo; Bichoutskaia, Elena; Taniguchi, Takashi; Watanabe, Kenji; Marsden, Alexander J; Wilson, Neil R; Beton, Peter H

    2015-01-14

    The adsorption of the alkane tetratetracontane (TTC, C44H90) on graphene induces the formation of a curved surface stabilized by a gain in adsorption energy. This effect arises from a curvature-dependent variation of a moiré pattern due to the mismatch of the carbon-carbon separation in the adsorbed molecule and the period of graphene. The effect is observed when graphene is transferred onto a deformable substrate, which in our case is the interface between water layers adsorbed on mica and an organic solvent, but is not observed on more rigid substrates such as boron nitride. Our results show that molecular adsorption can be influenced by substrate curvature, provide an example of two-dimensional molecular self-assembly on a soft, responsive interface, and demonstrate that the mechanical properties of graphene may be modified by molecular adsorption, which is of relevance to nanomechanical systems, electronics, and membrane technology. PMID:25469625

  3. Radiolysis of alanine adsorbed in a clay mineral

    International Nuclear Information System (INIS)

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

  4. Role of adsorbed water in radiolysis of polysaccharides

    International Nuclear Information System (INIS)

    The role of adsorbed water in radiolytic decomposition of polysaccharides (starch, dextran and cellulose) is considered. Irradiation of polysaccharide samples with natural moisture and preliminary dried in vacuum was conducted at room temperature by 60Co ?-rays in dose interval from 29 to 800 kGy, dose rate in irradiated volume is 2 Gy/s. It is pointed out that in all native polysaccharides two processes are induced by ?-irradiation. One proceeds with water adsorption, the second is accompanied by isolation of water, which accumulates in the sample irradiated and then is absorbed by the sample. The conclusion about participation first of water adsorbed and then water accumulated in dehydration process of primary macro-radicals is confirmed by the investigation results of H2 and CO2 accumulation dose dependences

  5. Adsorption studies of radon and xenon on different adsorbents

    International Nuclear Information System (INIS)

    Liquid noble gas detectors play a leading role for direct detection dark matter experiments. Particularly xenon with its high mass and the absence of radioactive isotopes is well suited as target material and used in the XENON project. To reduce background the detector of the next generation, the XENON1T detector, is planned to be operated with a dynamic, adsorption based purification system to clean the xenon from radon contamination. In the first part of this bachelor thesis, radon adsorption in presence of xenon was analyzed for different adsorbent samples, to find the best suited material for the radon removal system. In total one metal organic framework and two zeolites were tested. The second part of the thesis describes measurements of xenon adsorption isotherms on an activated carbon sample at different temperatures. These measurements should help to answer questions concerning the amount and type of adsorbent required to operate successfully the radon removal system planed for the XENON1T experiment.

  6. Removing 3,5-Dichlorophenol from Wastewater by Alternative Adsorbents

    Science.gov (United States)

    Kobeti?ová, Hana; Galbi?ková, Blanka; Šev?íková, Janka; Soldán, Maroš

    2014-12-01

    The main objective of this paper is to evaluate an efficiency of 3,5 - dichlorophenol removal from wastewater by using alternative adsorbents. Chlorophenols are organic compounds consisting of a benzene ring, OH groups and also atoms of chlorine. Chlorophenols may have a huge isomere variety that means there are differences in their chemical and physical properties. Due to their toxicity it is necessary to remove them from waste water and in this paper an alternative way of such process is described.

  7. Non-linear optical studies of adsorbates: Spectroscopy and dynamics

    International Nuclear Information System (INIS)

    In the first part of this thesis, we have established a systematic procedure to apply the surface optical second-harmonic generation (SHG) technique to study surface dynamics of adsorbates. In particular, we have developed a novel technique for studies of molecular surface diffusions. In this technique, the laser-induced desorption with two interfering laser beams is used to produce a monolayer grating of adsorbates. The monolayer grating is detected with diffractions of optical SHG. By monitoring the first-order second-harmonic diffraction, we can follow the time evolution of the grating modulation from which we are able to deduce the diffusion constant of the adsorbates on the surface. We have successfully applied this technique to investigate the surface diffusion of CO on Ni(111). The unique advantages of this novel technique will enable us to readily study anisotropy of a surface diffusion with variable grating orientation, and to investigate diffusion processes of a large dynamic range with variable grating spacings. In the second part of this work, we demonstrate that optical infrared-visible sum-frequency generation (SFG) from surfaces can be used as a viable surface vibrational spectroscopic technique. We have successfully recorded the first vibrational spectrum of a monolayer of adsorbates using optical infrared-visible SFG. The qualitative and quantitative correlation of optical SFG with infrared absorption and Raman scattering spectroscopies are examined and experimentally demonstrated. We have further investigated the possibility to use transient infrared-visible SFG to probe vibrational transients and ultrafast relaxations on surfaces. 146 refs

  8. Carbonaceous adsorbents in cryosorption pump applications; Future trends

    Science.gov (United States)

    Tripathi, S. Vijai; Kasthurirengan, S.; Udgata, S. S.; Gangradey, R.; Krishnamoorthy, V.; Surendra, Bhati

    2013-06-01

    Use of granular activated carbon in commercial cryosorption pumps is now, more or less well established. The development of advanced polymeric precursor based activated carbon adsorbents in various forms has opened a flood gate of possibilities vis-a-vis improvements in performance of cryosorption pumps, both in rate of adsorption and their ultimate capacity. This paper gives a summary of indigenous efforts towards this direction.

  9. Adsorbing Flotation of Copper Hydroxo Precipitates by Pyrite Fines

    OpenAIRE

    Zouboulis, a.I.; ??????????, ?.?.; Kydros, K.A.; Matis, K.A.; ??????, ?.?.; ?????, ?.?.

    2009-01-01

    The removal of copper ions from dilute aqueous solutions by the addition of mineral (pyrite) fine particles was undertaken by following an adsorbing (scavenging) flotation mechanism. Pyrite generally constitutes a residual or a solid industrial waste by-product in mixed sulfides processing plants. This paper suggests a further utilization for pyrite. The dissolved-air method was applied for solid/ liquid separation when the mineral particles were in the fine (subsieve) size range. Various unc...

  10. Quantum Films Adsorbed on Graphite: Third and Fourth Helium Layers

    OpenAIRE

    Pierce, Marlon; Manousakis, Efstratios

    2000-01-01

    Using a path-integral Monte Carlo method for simulating superfluid quantum films, we investigate helium layers adsorbed on a substrate consisting of graphite plus two solid helium layers. Our results for the promotion densities and the dependence of the superfluid density on coverage are in agreement with experiment. We can also explain certain features of the measured heat capacity as a function of temperature and coverage.

  11. Quantum Films Adsorbed on Graphite Third and Fourth Helium Layers

    CERN Document Server

    Pierce, M; Pierce, Marlon; Manousakis, Efstratios

    2001-01-01

    Using a path-integral Monte Carlo method for simulating superfluid quantum films, we investigate helium layers adsorbed on a substrate consisting of graphite plus two solid helium layers. Our results for the promotion densities and the dependence of the superfluid density on coverage are in agreement with experiment. We can also explain certain features of the measured heat capacity as a function of temperature and coverage.

  12. Preparation of lignin derivatives and their application as protease adsorbents

    OpenAIRE

    Xian-Su Cheng; Yin Lin; Run Fang

    2009-01-01

    Synthesis of two lignin derivatives, lignophenol and lignin-aminophenol, were presented in this article. The chemical structure and the func-tional groups of lignin derivatives were charac-terized through FT-IR analysis. The immobiliza-tion of three proteases (papain, trypsin and pepsin) on lignin and lignin derivatives was carried out using adsorption technique. The influence of contact time and pH on the enzyme adsorption by different adsorbents was inves-tigated. Furthermore, enzyme activi...

  13. Interfacial Friction of 4He Films Adsorbed on Porous Gold

    Science.gov (United States)

    Taniguchi, J.; Wataru, K.; Hasegawa, K.; Hieda, M.; Suzuki, M.

    2006-09-01

    We measured the interfacial friction of nonsuperfluid 4He films adsorbed on porous gold using the quartz-crystal microbalance (QCM) technique. Above about the first layer completion, decoupling due to a decrease in the interfacial friction was observed for a large oscillation amplitude of 1.6 nm below a certain temperature TS, which depends on the areal density of 4He. The completion of the first layer and the inert layer was found to strongly affect the interfacial friction.

  14. Adsorption capacity of various adsorbents for decolorization of wastewater

    OpenAIRE

    Rom?evi?, Gorana

    2014-01-01

    Adsorption is applied for the removal of dyes from wastewater effluent from textile and other industries. Dyes from wastewater need to be removed before it mixes with water bodies. Among the treatment options, adsorption appears to have considerable potential for the removal of colour from wastewaters. Activated carbon is the most widely used adsorbent, but its use is limited due to its high cost. This cost problem has led to a search for the use of alternate cheap and efficient materials. ...

  15. Mercury(II) Removal with Modified Magnetic Chitosan Adsorbents

    OpenAIRE

    George Z. Kyzas; Eleni A. Deliyanni

    2013-01-01

    Two modified chitosan derivatives were prepared in order to compare their adsorption properties for Hg(II) removal from aqueous solutions. The one chitosan adsorbent (CS) is only cross–linked with glutaraldehyde, while the other (CSm), which is magnetic, is cross-linked with glutaraldehyde and functionalized with magnetic nanoparticles (Fe3O4). Many possible interactions between materials and Hg(II) were observed after adsorption and explained via characterization with various techniques (SEM...

  16. Infrared Analysis Of Enzymes Adsorbed Onto Model Surfaces

    Science.gov (United States)

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

    1989-12-01

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

  17. Purification of Sardinella sp., Oil: Centrifugation and Bentonite Adsorbent

    OpenAIRE

    S.H. Suseno; Nurjanah, A.M. Jacoeb; Saraswati

    2014-01-01

    Centrifugation and purification using adsorbents is one example of a fish oil refining techniques applied to reduce impurities of fish oil. The study aimed to determine the sardine oil quality before treatment, to determine yield of fish oil after centrifugation treatment and to determine the influence of centrifugation speed and bentonite concentration on sardine oil quality. Factorial design with two factors was used in this study. Level of free fatty acid and peroxide value before purifica...

  18. Non-linear optical studies of adsorbates: Spectroscopy and dynamics

    Energy Technology Data Exchange (ETDEWEB)

    Zhu, Xiangdong.

    1989-08-01

    In the first part of this thesis, we have established a systematic procedure to apply the surface optical second-harmonic generation (SHG) technique to study surface dynamics of adsorbates. In particular, we have developed a novel technique for studies of molecular surface diffusions. In this technique, the laser-induced desorption with two interfering laser beams is used to produce a monolayer grating of adsorbates. The monolayer grating is detected with diffractions of optical SHG. By monitoring the first-order second-harmonic diffraction, we can follow the time evolution of the grating modulation from which we are able to deduce the diffusion constant of the adsorbates on the surface. We have successfully applied this technique to investigate the surface diffusion of CO on Ni(111). The unique advantages of this novel technique will enable us to readily study anisotropy of a surface diffusion with variable grating orientation, and to investigate diffusion processes of a large dynamic range with variable grating spacings. In the second part of this work, we demonstrate that optical infrared-visible sum-frequency generation (SFG) from surfaces can be used as a viable surface vibrational spectroscopic technique. We have successfully recorded the first vibrational spectrum of a monolayer of adsorbates using optical infrared-visible SFG. The qualitative and quantitative correlation of optical SFG with infrared absorption and Raman scattering spectroscopies are examined and experimentally demonstrated. We have further investigated the possibility to use transient infrared-visible SFG to probe vibrational transients and ultrafast relaxations on surfaces. 146 refs.

  19. Toxicity of Uranium Adsorbent Materials using the Microtox Toxicity Test

    Energy Technology Data Exchange (ETDEWEB)

    Park, Jiyeon; Jeters, Robert T.; Gill, Gary A.; Kuo, Li-Jung; Bonheyo, George T.

    2015-10-01

    The Marine Sciences Laboratory at the Pacific Northwest National Laboratory evaluated the toxicity of a diverse range of natural and synthetic materials used to extract uranium from seawater. The uranium adsorbent materials are being developed as part of the U. S. Department of Energy, Office of Nuclear Energy, Fuel Resources Program. The goal of this effort was to identify whether deployment of a farm of these materials into the marine environment would have any toxic effects on marine organisms

  20. Supercritical fluid adsorption and desorption of lipids on various adsorbents

    OpenAIRE

    S?kerget, Mojca; Knez, Z?eljko

    2012-01-01

    adsorption and desorption on adsorbents such as silica gel and neusilin using supercritical CO2 as mobile phase was investigated. The experiments were performed at 40 °C and in the pressure range from 13 to 30 MPa. Adsorption kinetic lines were determined by analysingbreakthrough curves. Several parameters such as rate of adsorption and desorption, loading, desorbed quantity and diffusion coefficients in solid phase were calculated.

  1. Distribution of metal and adsorbed guest species in zeolites

    International Nuclear Information System (INIS)

    Because of their high internal surface areas and molecular-size cavity dimensions, zeolites are used widely as catalysts, shape- selective supports, or adsorbents in a variety of important chemical processes. For metal-catalyzed reactions, active metal species must be dispersed to sites within the zeolite pores that are accessible to diffusing reactant molecules. The distribution of the metal, together with transport and adsorption of reactant molecules in zeolite powders, are crucial to ultimate catalyst performance. The nature of the metal or adsorbed guest distribution is known, however, to be dramatically dependent upon preparatory conditions. Our objective is to understand, at the molecular level, how preparatory treatments influence the distribution of guest species in zeolites, in order that macroscopic adsorption and reaction properties of these materials may be better understood. The sensitivity of xenon to its adsorption environment makes 129Xe NMR spectroscopy an important diagnostic probe of metal clustering and adsorbate distribution processes in zeolites. The utility of 129Xe NMR depends on the mobility of the xenon atoms within the zeolite-guest system, together with the length scale of the sample heterogeneity being studied. In large pore zeolites containing dispersed guest species, such as Pt--NaY, 129Xe NMR is insensitive to fine structural details at room temperature

  2. Preparation of lignin derivatives and their application as protease adsorbents

    Directory of Open Access Journals (Sweden)

    Xian-Su Cheng

    2009-12-01

    Full Text Available Synthesis of two lignin derivatives, lignophenol and lignin-aminophenol, were presented in this article. The chemical structure and the func-tional groups of lignin derivatives were charac-terized through FT-IR analysis. The immobiliza-tion of three proteases (papain, trypsin and pepsin on lignin and lignin derivatives was carried out using adsorption technique. The influence of contact time and pH on the enzyme adsorption by different adsorbents was inves-tigated. Furthermore, enzyme activity recovery was also evaluated. Results showed that lignin and lignin derivatives could adsorb proteases effectively and the adsorption capacity of lingo- phenol and lignin-aminophenol was higher than that of pure lignin. Meanwhile, the activity re-covery of papain and pepsin immobilized on lignin derivatives was very high. This pheno- menon suggested that there is a supramole- cular interaction between enzymes and lignin derivatives which do not inhibit enzyme activity. Therefore, lignophenol and lignin-aminophenol are both promising adsorbents for enzyme im-mobilization under acid and neutral conditions.

  3. Theoretical analyzing of monomers adsorbing in nano-slits.

    Science.gov (United States)

    Liu, Meitang; Pu, Minfeng; Ma, Hongwen; Mu, Bozhong

    2011-12-01

    A revised model based on Aranovich-Donohue Theory was built in this paper and was used to indicate the adsorbing behaviors of monomers in nano slits. This work tried to establish a theoretical model and get the fundamental mechanisms of the in situ-monomer-intercalation process which is the most common production method of polymer-layer silicate intercalated nanocomposite. According to the results, the multilevel adsorption and 3D phase transition phenomenon in nano slits predicted by Aranovich-Donohue Theory do not exit in reality. They are probably aroused by system errors caused by simple mean field approximation treatments. The nano slits have obvious boundary effects on density profile distribution of monomers. When the pore size increase, the density differences will be diminished. The adsorbing amounts will go up sharply in a narrow low-bulk-concentration region and will decrease rapidly at most bulk-concentration-regions accompanied by the increasing of interaction energies of adsorbates. This should attribute to the capillary condensation phenomenon. The newly established model will be definitely helpful to reveal the fundamental mechanisms of in situ-monomer-intercalation process for polymer-layer silicate intercalated nanocomposite. PMID:22409076

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2015-06-02

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

  5. Elimination of dyes from aqueous solutions using iron oxides and chitosan as adsorbents: a comparative study

    Directory of Open Access Journals (Sweden)

    Silvina Pirillo

    2009-01-01

    Full Text Available This work investigates the adsorption of Alizarin, Eriochrome Blue Black R and Fluorescein using chitosan, goethite and magnetite as adsorbents. For Alizarin, the best adsorbent is chitosan with a Langmuir parameter of 15.8 mmol dye/g adsorbent. For Eriochrome Blue Black R only 1.94 mmol dye/g chitosan is adsorbed. Langmuir parameters for the Alizarin adsorption on both iron oxides display one or two orders of magnitude lower than for chitosan and two orders of magnitude lower in the case of Eriochrome Blue Black R. Fluorescein does not adsorb in appreciable amounts on chitosan and it presents the lower affinity on the iron oxides.

  6. Current status of adsorbent for metal ions with radiation grafting and crosslinking techniques

    Science.gov (United States)

    Seko, Noriaki; Tamada, Masao; Yoshii, Fumio

    2005-07-01

    Removal of toxic metals from streaming water and ground water is important task to preserve environment. Radiation processing of grafting and crosslinking can synthesis adsorbent having high performances. Graft adsorbent can be synthesized by using the conventional polymer like polyethylene having variety shapes such as membrane, cloth, and fiber. Especially, the obtained fibrous adsorbent has 100 times higher rate of adsorption than that of commercialized resin. Fibrous adsorbent of iminodiacetate was applied to the removal of cadmium from the scallop waste. Furthermore, the amidoxime adsorbent is useful for recovery of rare metals such as uranium and vanadium in seawater. Novel fibrous adsorption for arsenic was synthesized by direct grafting of phosphoric monomer and following zirconium-loading. Crosslinked natural polymers like carboxymethyl chitin-chitosan in the paste-like state are applicable for the metal adsorbent. This adsorbent can be biodegraded after usage.

  7. Structural, compositional and morphological studies of thermally evaporated MoO3 thin films

    Science.gov (United States)

    Senthilkumar, R.; Ravi, G.

    2014-04-01

    Molybdenum oxide (MoO3) nanostructures were grown on different substrates such as glass, indium tin oxide coated glass and fluorine doped glass by thermal evaporation of MoO3 powder at elevated temperature (750°C) using tube furnace without any catalyst and then by subsequent O2/Ar flow rate. The morphology, composition and crystal structure were examined by using SEM, EDAX, Laser Raman and XRD. The films are polycrystalline with well-defined diffraction peaks and it consist of MoO3 with ?-orthorhombic structure. The synthesized MoO3 belongs to different morphologies, generally nanobelt and nanohunk structures. The EDAX spectra confirm the films are composed only of Mo and O atoms. The O/Mo ratio is nearly equal to 3 that shows the stoichiometry of MoO3.

  8. Structural, compositional and morphological studies of thermally evaporated MoO{sub 3} thin films

    Energy Technology Data Exchange (ETDEWEB)

    Senthilkumar, R., E-mail: raviganesa@rediffmail.com, E-mail: gravicrc@gmail.com; Ravi, G., E-mail: raviganesa@rediffmail.com, E-mail: gravicrc@gmail.com [Department of Physics, Alagappa University, Karaikudi - 630003 (India)

    2014-04-24

    Molybdenum oxide (MoO{sub 3}) nanostructures were grown on different substrates such as glass, indium tin oxide coated glass and fluorine doped glass by thermal evaporation of MoO{sub 3} powder at elevated temperature (750°C) using tube furnace without any catalyst and then by subsequent O{sub 2}/Ar flow rate. The morphology, composition and crystal structure were examined by using SEM, EDAX, Laser Raman and XRD. The films are polycrystalline with well-defined diffraction peaks and it consist of MoO{sub 3} with ?-orthorhombic structure. The synthesized MoO{sub 3} belongs to different morphologies, generally nanobelt and nanohunk structures. The EDAX spectra confirm the films are composed only of Mo and O atoms. The O/Mo ratio is nearly equal to 3 that shows the stoichiometry of MoO{sub 3}.

  9. Mixed waste: The treatment of organic radioactive waste by means of adsorbents

    International Nuclear Information System (INIS)

    Full text: The work described in this paper has been carried in the radioactive waste treatment facilities of the Nuclear Research Center Lo Aguirre, CEN LA, which are operated by Radioactive Waste Management Unit, UGDR. This last, centralizes its activities in order to manage all radioactive waste generated in the country due to the nuclear development. Features of danger and risks presented by organic radioactive liquid waste, make the need to develop a practicable alternative for its treatment and to allow the conditioning towards a suitable final disposal The raw material for this work, is an organic liquid waste arising from scintillation techniques, contaminated with Tritium. This mixed waste has to be treated and then conditioned in a solid form within a 200 I container, according with actual acceptance criteria for our temporary store for radioactive waste. The best formulation which allows to immobilize the liquid waste was determined. The first step consists in the adsorption treatment that waste is humbled. From the available adsorbents, two types were studied: adsorption granulat and diatomaceous earth. From the waste management standpoint, results with diatomaceous earth present physical characteristics better than the other Following, the second stage is the immobilization, which is achieved in a cement matrix made with puzzolanic cement (Polpaico 400) made in Chile. Later, due to cost and availability in the country, the diatomaceous earth is selected for the study, in the form of celite which is comparatively economic. The best mixture, with regard to physical feature, has the following composition: a 0.35 (w/w) water/cement ratio, which represents the needed quantity to obtain workability in the mixture, and it is the minimum amount of water to hydrating the cement; a waste/adsorbent ratio of 0.5 (v/v), in which the organic liquid is completely adsorbed and it is incorporated into the crystalline system of the solid form; and an adsorbed waste/cement ratio of 0.8 (w/w). In this mixture, quantity of cement is the minimum required to obtain a solid product with the due mechanical feature which stands the compression resistance desired. Setting time is about 8 hours. Samples are tested, at 7, 14,21 and 28 days since they were prepared to evaluate compression resistance, obtaining the minimum desired at 14 days aged with a 52 kg/cm2, which increase to 28 days. Weight composition of the final mixture is a 22.9% organic waste, 46.5 % cement, 14.3 % celite, and a 16.3 % water. A real scale (200 I standard drum) was prepared to study features in plant also. As a conclusion, it is shown that it is possible to treat the radioactive organic liquid, to obtain a solid product that complies with qualitative and quantitative physical parameters required to disposed of. Performance at real scale is simple and results are better than those in lab seal, reaching at 14 days aged a compression resistance upper than 100 kg/cm2. Research is followed to determine the leach test, the radiation effect and thermal cycle stability in samples. (author)

  10. Preparation and Characterization of Chitosan/Feldspar Biohybrid as an Adsorbent: Optimization of Adsorption Process via Response Surface Modeling

    Science.gov (United States)

    Yazdani, Maryam; Bahrami, Hajir; Arami, Mokhtar

    2014-01-01

    Chitosan/feldspar biobased beads were synthesized, characterized, and tested for the removal of Acid Black 1 dye from aquatic phases. A four-factor central composite design (CCD) accompanied by response surface modeling (RSM) and optimization was used to optimize the dye adsorption by the adsorbent (chitosan/feldspar composite) in 31 different batch experiments. Independent variables of temperature, pH, initial dye concentration, and adsorbent dose were used to change to coded values. To anticipate the responses, a quadratic model was applied. Analysis of variance (ANOVA) tested the significance of the process factors and their interactions. The adequacy of the model was investigated by the correlation between experimental and predicted data of the adsorption and the calculation of prediction errors. The results showed that the predicted maximum adsorption amount of 21.63?mg/g under the optimum conditions (pH 3, temperature 15°C, initial dye concentration 125?mg/L, and dose 0.2?g/50?mL) was close to the experimental value of 19.85?mg/g. In addition, the results of adsorption behaviors of the dye illustrated that the adsorption process followed the Langmuir isotherm model and the pseudo-second-order kinetic model. Langmuir sorption capacity was found to be 17.86?mg/g. Besides, thermodynamic parameters were evaluated and revealed that the adsorption process was exothermic and favourable. PMID:24587722

  11. Carbon fibre composite for ventilation air methane (VAM) capture.

    Science.gov (United States)

    Thiruvenkatachari, Ramesh; Su, Shi; Yu, Xin Xiang

    2009-12-30

    Coal mine methane (CMM) is not only a hazardous greenhouse gas but is also a wasted energy resource, if not utilised. This paper evaluates a novel adsorbent material developed for capturing methane from ventilation air methane (VAM) gas in underground coal mines. The adsorbent material is a honeycomb monolithic carbon fibre composite (HMCFC) consisting of multiple parallel flow-through channels and the material exhibits unique features including low pressure drop, good mechanical properties, ability to handle dust-containing gas streams, good thermal and electrical conductivity and selective adsorption of gases. During this study, a series of HMCFC adsorbents (using different types of carbon fibres) were successfully fabricated. Experimental data demonstrated the proof-of-concept of using the HMCFC adsorbent to capture methane from VAM gas. The adsorption capacity of the HMCFC adsorbent was twice that of commercial activated carbon. Methane concentration of 0.56% in the inlet VAM gas stream is reduced to about 0.011% after it passes through the novel carbon fibre composite adsorbent material at ambient temperature and atmospheric pressure. This amounts to a maximum capture efficiency of 98%. These encouraging laboratory scale studies have prompted further large scale trials and economic assessment. PMID:19733967

  12. Material prepared from drinking waterworks sludge as adsorbent for ammonium removal from wastewater

    Science.gov (United States)

    Yang, Lan; Wei, Jie; Liu, Zhongyuan; Wang, Jianli; Wang, Dongtian

    2015-03-01

    Drinking waterworks sludge (DWS) is not an effective adsorbent for ammonium removal without any treatment. In this study, DWS was used as a starting material to prepare ammonium adsorbent (M-DWS) by means of an ultrasonic assisted extraction and synthesis method. Two materials (M-DWS1# and M-DWS2#) were prepared according to two different routes. The composition, structure, and surface properties of DWS and M-DWS were characterized and their ammonium adsorption abilities were examined. Characterization results showed that the lamellar structure of DWS was converted into the spherical units of M-DWS and that the cation exchange capacity and specific surface area of M-DWS were many times higher than that of DWS. Batch test results indicated that the adsorption equilibrium data of M-DWS fitted well to both the Langmuir and Frendlich isotherms. The maximum adsorption capacity of M-DWS1# and M-DWS2# evaluated from the Langmuir isotherm was 6.11 mg/g and 5.10 mg/g, respectively. It was also observed that the initial pH affected ammonium adsorption on M-DWS greatly. Under an optimum pH of 7-8, the highest ammonium removal rate of 90% for M-DWS1# and 80% for M-DWS2# were achieved at an initial concentration of 50 mg NH4+/L. The advantage of M-DWS2# lies in its higher yield and less waste discharge compared with M-DWS1#.

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

    Science.gov (United States)

    Sakai, Toshio; Da Loves, Albar; Okada, Tomohiko; Mishima, Shozi

    2013-03-15

    We report here on the removal of alkylphenols (phenol, 4-n-propylphenol, 4-n-heptylphenol and 4-nonylphenol) dissolved in water using the composite particles of nanocrystalline titania and alkyltrimethylammonium bromide (CnH2n+1N(CH3)3Br, CnTAB; n=12, 14, 16 and 18) (named as TiO2/CnTAB Nanoskeleton) as adsorbents and photocatalysts. In particular, the adsorption of alkylphenols onto TiO2/CnTAB Nanoskeleton in water was investigated in terms of hydrophobic interaction between alkylphenols and CnTAB, surface area, pore structure and crystal size of TiO2/CnTAB Nanoskeleton. We revealed that CnTAB incorporated in the TiO2/CnTAB Nanoskeleton promotes the adsorption of alkylphenols onto TiO2/CnTAB Nanoskeleton due to the hydrophobic interaction between alkylphenols and CnTAB. On the other hand, the surface area, pore structure and crystal size of TiO2/CnTAB Nanoskeleton did not affect the adsorption of alkylphenols onto TiO2/CnTAB Nanoskeleton. We also found that the alkylphenols dissolved in water were completely removed by the combination of adsorption and photocatalytic degradation by the TiO2/CnTAB Nanoskeleton under UV irradiation. These results prove that the TiO2/CnTAB Nanoskeleton acts as in tandem an adsorbent and a photocatalyst for removal of alkylphenols dissolved in water. PMID:23419907

  14. Electron beam irradiation of dimethyl-(acetylacetonate) gold(III) adsorbed onto solid substrates

    International Nuclear Information System (INIS)

    Electron beam induced deposition of organometallic precursors has emerged as an effective and versatile method for creating two-dimensional and three-dimensional metal-containing nanostructures. However, to improve the properties and optimize the chemical composition of nanostructures deposited in this way, the electron stimulated decomposition of the organometallic precursors must be better understood. To address this issue, we have employed an ultrahigh vacuum-surface science approach to study the electron induced reactions of dimethyl-(acetylacetonate) gold(III) [AuIII(acac)Me2] adsorbed onto solid substrates. Using thin molecular films adsorbed onto cooled substrates, surface reactions, reaction kinetics, and gas phase products were studied in the incident energy regime between 40 and 1500 eV using a combination of x-ray photoelectron spectroscopy (XPS), reflection absorption infrared spectroscopy (RAIRS), and mass spectrometry (MS). XPS and RAIRS data indicate that electron irradiation of AuIII(acac)Me2 is accompanied by the reduction in AuIII to a metallic Au0 species embedded in a dehydrogenated carbon matrix, while MS reveals the concomitant evolution of methane, ethane, carbon monoxide, and hydrogen. The electron stimulated decomposition of AuIII(acac)Me2 is first-order with respect to the surface coverage of the organometallic precursor, and exhibits a rate constant that cursor, and exhibits a rate constant that is proportional to the electron flux. At an incident electron energy of 520 eV, the total reaction cross section was ?3.6x10-16 cm2. As a function of the incident electron energy, the maximum deposition yield was observed at ?175 eV. The structure of discrete Au-containing deposits formed at room temperature by rastering an electron beam across a highly ordered pyrolytic graphite substrate in the presence of a constant partial pressure of AuIII(acac)Me2 was also investigated by atomic force microscopy.

  15. Aluminium hydro(oxide)-based (AO) adsorbent for defluoridation of drinking water: Optimisation, performance comparison, and field testing

    Scientific Electronic Library Online (English)

    Eyobel, Mulugeta; Feleke, Zewge; C Annette, Johnson; Bhagwan Singh, Chandravanshi.

    2015-01-01

    Full Text Available In this study, the performance of different aluminium hydroxide-based adsorbents was compared in terms of fluoride adsorption capacity, potential for repetitive regeneration, surface acidity and surface site concentrations. The adsorbents were aluminium hydro(oxide) (AO), activated alumina (AA), and [...] pseudoboehmite (PB). The AO adsorbent was synthesised at different OH:Al ratios to optimise the fluoride adsorption capacity. The AO was pilot tested in a rural community in the Ethiopian Rift Valley where groundwaters are heavily enriched with fluoride. The maximum fluoride uptake was achieved for the AO adsorbent synthesised at OH:Al ratios between 2.5 and 2.7. The fluoride adsorption capacity of the adsorbents determined from mini-column studies was found to be 10.6, 1.9, and 2.4 mg/g for AO, AA, and PB, respectively. This significant difference in fluoride adsorption capacity is strongly related to the surface acidity and surface site concentration. The surface acidity (1.57 meq/g) and surface site concentration (0.74 meq/g) for AO is higher than that for AA and PB. The elemental composition analysis showed that AO has a lower % Al2O3 content than AA and PB, but higher sulphate (19.4%) and iron (2.2%) content. High resolution 27Al Magic Angle Spinning Nuclear Magnetic Resonance (27Al MAS NMR) spectra of AO, AA, and PB were recorded, to analyse the coordination geometry of solid Al species and the results showed that aluminium is coordinated octahedrally and tetrahedrally in all cases. Regeneration experiments showed that AA and PB can be regenerated for more than 3 cycles, whereas the potential for regeneration of AO for more than 3 cycles is limited. The results from a community defluoridation plant showed that fluoride in the feed water (8-10 mg/?) is removed below 0.1 mg/?. The average adsorption capacity was determined to be 2.11 mg/g based on continuous field monitoring results obtained until the fluoride content in the treated water exceeded the breakthrough value of 1.5 mg/?. No major operational problems and complaints from the beneficiaries were experienced during operation.

  16. Experiment on the thermal conductivity and permeability of physical and chemical compound adsorbents for sorption process

    Science.gov (United States)

    Jin, Z. Q.; Wang, L. W.; Jiang, L.; Wang, R. Z.

    2013-08-01

    For the adsorbents in the application of refrigeration, the density of the material inside the adsorber changes because the adsorption/desorption of the refrigerant inside the adsorbents. Consequently the thermal conductivity and permeability of the adsorbents also change. In order to investigate the heat and mass transfer performance of consolidated compound adsorbent under the different equilibrium state of adsorption/desorption, the thermal conductivity and permeability test system is set up using the guarded hot plate measuring method and the principle of Ergun equation. Then various mass ratios between adsorbent and matrix of consolidated physical and chemical compound adsorbents are developed and tested under different ammonia adsorption quantity. Result shows that the thermal conductivity and permeability have strong dependence with the ratios and consolidated density of the compound adsorbent. Meanwhile, the thermal conductivity and permeability of the chemical compound adsorbents vary significantly with different adsorption quantity of ammonia, and the values for the physical compound adsorbents almost maintain a constant value with different values of adsorption quantity.

  17. Adsorption of fluoride from aqueous solution by enhanced chitosan/bentonite composite.

    Science.gov (United States)

    Liu, Qian; Huang, Ruihua; Yang, Bingchao; Liu, Yanping

    2013-01-01

    In this work, enhanced chitosan/bentonite composite was prepared by treating chitosan/bentonite composite with concentrated hydrochloric acid (HCl). The adsorption of fluoride ions from aqueous solution onto the enhanced chitosan/bentonite composite was investigated. Adsorption studies were performed in a batch system, and the effects of various parameters, such as the pH value of the solution, adsorbent dosage and initial fluoride concentration, were evaluated. The optimum operating conditions for fluoride removal by the enhanced chitosan/bentonite composite were pH = 7 or so, and adsorbent dosage =1.2 g. Increasing initial fluoride concentration reduced the adsorption of fluoride onto the enhanced chitosan/bentonite composite. Furthermore, the presence of other co-anions weakened the adsorption of fluoride onto this adsorbent. The equilibrium adsorption isotherms were well described by both the Freundlich and Langmuir models. The maximum monolayer adsorption capacity was 2.95 mg/g at 293 K. PMID:24225111

  18. Advanced fire-resistant forms of activated carbon and methods of adsorbing and separating gases using same

    Energy Technology Data Exchange (ETDEWEB)

    Xiong, Yongliang; Wang, Yifeng

    2015-02-03

    Advanced, fire-resistant activated carbon compositions useful in adsorbing gases; and having vastly improved fire resistance are provided, and methods for synthesizing the compositions are also provided. The advanced compositions have high gas adsorption capacities and rapid adsorption kinetics (comparable to commercially-available activated carbon), without having any intrinsic fire hazard. They also have superior performance to Mordenites in both adsorption capacities and kinetics. In addition, the advanced compositions do not pose the fibrous inhalation hazard that exists with use of Mordenites. The fire-resistant compositions combine activated carbon mixed with one or more hydrated and/or carbonate-containing minerals that release H.sub.2O and/or CO.sub.2 when heated. This effect raises the spontaneous ignition temperature to over 500.degree. C. in most examples, and over 800.degree. C. in some examples. Also provided are methods for removing and/or separating target gases, such as Krypton or Argon, from a gas stream by using such advanced activated carbons.

  19. ISOTHERMAL AND THERMODYNAMICAL MODELING OF CHROMIUM (III) ADSORPTION BY COMPOSITES OF POLYANILINE WITH RICE HUSK AND SAW DUST

    OpenAIRE

    FARAH KANWAL; RABIA REHMAN; TARIQ MAHMUD; JAMIL ANWAR; RABIA ILYAS

    2012-01-01

    The adsorption of Cr (III) from water by polyaniline composites with rice husk and saw dust of Eucalyptus camaldulensis has been investigated in this study. The surface of adsorbents was characterized by FT-IR. Effect of various operational conditions like agitation time, initial pH, adsorbent dose, particle size of composites and temperature were studied in batch mode. The suitability of the data was confirmed by Langmuir and Freundlich isotherms. Thermodynamic studies showed that adsorption...

  20. Detection of adsorbed water and hydroxyl on the moon

    Science.gov (United States)

    Clark, R.N.

    2009-01-01

    Data from the Visual and Infrared Mapping Spectrometer (VIAAS) on Cassini during its flyby of the AAoon in 1999 show a broad absorption at 3 micrometers due to adsorbed water and near 2.8 micrometers attributed to hydroxyl in the sunlit surface on the AAoon. The amounts of water indicated in the spectra depend on the type of mixing and the grain sizes in the rocks and soils but could be 10 to 1000 parts per million and locally higher. Water in the polar regions may be water that has migrated to the colder environments there. Trace hydroxyl is observed in the anorthositic highlands at lower latitudes.

  1. Models for Monolayers Adsorbed on a Square Substrate

    CERN Document Server

    Biham, O; Vidali, G; Biham, Ofer; Vidali, Gianfranco

    1992-01-01

    Motivated by recent experimental studies of Hg and Pb monolayers on Cu(001) we introduce a zero temperature model of a monolayer adsorbed on a square substrate. Lennard-Jones potentials are used to describe the interaction between pairs of adlayer-adlayer and adlayer-substrate atoms. We study a special case in which the monolayer atoms form a perfect square structure and the lattice constant, position and orientation with respect to the substrate can vary to minimize the energy. We introduce a rule based on the Farey tree construction to generate systematically the most energetically favored phases and use it to calculate the phase diagram in this model.

  2. Slippage of 4He films adsorbed on porous gold

    Science.gov (United States)

    Wataru, Kazuhisa; Taniguchi, Junko; Hieda, Mitsunori; Suzuki, Masaru

    2005-08-01

    We measured the slippage of nonsuperfluid 4He films adsorbed on a porous gold substrate using the quartz-crystal microbalance (QCM) technique. The substrate has a highly uniform porous structure, and its effective surface area was 20 times larger than that of a flat substrate. It was found that the degree of slippage between 4He films and the substrate increases below a certain temperature TS, and that TS decreases with increasing 4He areal density. This increase depends strongly on the oscillating amplitude of the quartz crystal.

  3. Effects of adsorbates on Zircaloy oxidation in air

    International Nuclear Information System (INIS)

    The air-oxidation of Zry and the effects of adsorbates on the oxidation are found by the intermittent measurement of the weight gain of specimens. NaC1 enhances the oxidation, where nonuniform stresses on the surface and C1 ions are the cause. LiOH also enhances the oxidation, where the initial oxide formed by LiOH seems to the reason. The effects of fluorides on oxidation are also measured. NaF is most harmful and KF follows next. LiF does not effect the oxidation of Zry. Diffusion of fluorides in oxide determines the enhancement. (author)

  4. Effect of adsorbents on the absorption of lansoprazole with surfactant.

    Science.gov (United States)

    Ito, Yukako; Arai, Harumi; Uchino, Kaori; Iwasaki, Kouji; Shibata, Nobuhito; Takada, Kanji

    2005-01-31

    Lansoprazole (LPZ) is a representative drug that shows a high inter-subject variation of bioavailability (BA). Solid preparation composed of surfactant, adsorbent and LPZ were prepared to improve the dissolution and absorption of LPZ, and the BA of LPZ was measured in rats and dogs. As surfactant, Tween 80, polyoxy 60 hydrogenated caster oil derivative (HCO-60) and PEG-8 caprylic/capric glycerides (Labrasol) were used. As adsorbant, porous silicon dioxide (Sylysia 550, 320), magnesium aluminometa silicate (Neusilin S2, NS2N, US2) and porous calcium silicate (Florite RE) were used. After small intestinal administration of LPZ, 5.0 mg/kg, solution with HCO-60 showed the highest plasma LPZ concentration versus time curve of which C(max) and AUC was 0.46+/-0.01 microg/mL and 0.73+/-0.03 microgh/mL. By comparing to that after i.v. injection of LPZ solution, 2.0 mg/kg, the BA of LPZ from HCO-60 solution was 39.0%, which was about seven times higher than that of LPZ powder. To solidify the LPZ solution with HCO-60, adsorbents were used and the obtained solid preparations were used for in vitro release experiment. Sylysia 320, Neusilin S2 and Neusilin NS2 showed the T50% of about 1h. To evaluate the BA of these solid preparations, absorption study was performed in rats. Sylysia 550 system showed the higher AUC than other systems, showing the BA of 28.1%. Sylysia 550 system was filled in an enteric capsule and was orally administered to dogs and BA was compared with enteric tablet. The AUC of Sylysia 550 system was 2.16+/-0.26 microgh/mL and was greater than enteric tablet and the BA of 71.7% was obtained. Solid system composed of LPZ, surfactant and adsorbent has suggested the possibility as a good tool to improve the BA of LPZ. PMID:15652200

  5. Pinwheel and herringbone phases in systems of adsorbed molecules

    Science.gov (United States)

    Mederos, L.; Chacón, E.; Tarazona, P.

    1990-11-01

    We present a study of the phase diagram of molecules adsorbed on a triangular lattice, with quadrupole-quadrupole interactions and including the presence of vacancies. We analyze the effects of the short-range correlations with use of the cluster variational method, and we find that the pinwheel phase, which was only marginally stable in the mean-field approximation, is stabilized in a finite region of the temperature-density phase diagram. However, the long-range correlations, which are still missing in our approximation, may produce important changes in the phase diagram.

  6. CHARACTERIZATION OF MANGROVE BARK ADSORBENT AND ITS APPLICATION IN THE REMOVAL OF TEXTILE DYES FROM AQUEOUS SOLUTIONS

    OpenAIRE

    TAN LEAN SEEY; MOHD JAIN NOORDIN MOHD KASSIM

    2012-01-01

    Mangrove bark, a natural, low-cost agricultural waste in Malaysia has been studied for its potential application as an adsorbent in its modified form. Adsorbent was prepared by pre-treating the mangrove bark with formaldehyde. The adsorbent was characterized before applied as an adsorbent to adsorb textile dyes. In this study, the removal of a reactive (Reactive Black 5) and a basic (Malachite Green) dye from aqueous solutions were investigated. Batch experiments were carried out in this stud...

  7. Improving the Quality of Sardine Oil (Sardinella sp.) from Pekalongan-Indonesia Using Centrifugation and Adsorbents (Attapulgite, Bentonite and Zeolite)

    OpenAIRE

    Sugeng Heri Suseno; Jeny Ernawati Tambunan; Bustami Ibrahim; Ayu Fitri Izaki

    2014-01-01

    Fish oil by-product is generally of poor quality and therefore cannot be directly used, so it must be purification. Fish oil purification can be done by treatment centrifugation and addition adsorbent. The purpose of this study is to determine the best treatment addition adsorbent to improve the quality of fish oil. Fish oil purification is done by treatment using centrifugation and then adsorbed by the adsorbent. The lowest peroxide value on providing a combination of adsorbent attapulgite b...

  8. Equilibrium Adsorption of heavy Metals from Aqueous Solutions onto Poly aniline Stannic(IV) Phosphate Composite

    International Nuclear Information System (INIS)

    An adsorbent material has been prepared by immobilization of stannic(IV) phosphate within poly aniline composite. The produced adsorbent exhibit a high adsorption potential for Pb(II), Cd(Il) and Zn(lI) from aqueous solutions. The influence of initial metal ion concentration, adsorbent dose, ph and temperature on metal ion removal has been studied. The process was found to follow a first order rate kinetics. Thc intra-particle diffusion of metal ions through pores in the adsorbent was to be the main rate limiting step. The equilibrium data fit well with Langmuir adsorption isotherm model. The selectivity order of the adsorbent towards the metal ions was Pb(Il) > Cd(Il) >Zn(II). The adsorption rate constant and thermodynamic parameters were also given to predict the nature of adsorption

  9. Preparation and characterization of novel carbon dioxide adsorbents based on polyethylenimine-modified Halloysite nanotubes.

    Science.gov (United States)

    Cai, Haohao; Bao, Feng; Gao, Jie; Chen, Tao; Wang, Si; Ma, Rui

    2015-05-01

    New nano-sized carbon dioxide (CO2) adsorbents based on Halloysite nanotubes impregnated with polyethylenimine (PEI) were designed and synthesized, which were excellent adsorbents for the capture of CO2 at room temperature and had relatively high CO2 adsorption capacity. The prepared adsorbents were characterized by various techniques such as Fourier transform infrared spectrometry, gel permeation chromatography, dynamic light scattering, thermogravimetry, thermogravimetry-Fourier transform-infrared spectrometry, scanning electron microscopy and transmission electron microscopy. The adsorption characteristics and capacity were studied at room temperature, the highest CO2 adsorption capacity of 156.6?mg/g-PEI was obtained and the optimal adsorption capacity can reach a maximum value of 54.8?mg/g-adsorbent. The experiment indicated that this kind of adsorbent has a high stability at 80°C and PEI-impregnated adsorbents showed good reversibility and stability during cyclic adsorption-regeneration tests. PMID:25381878

  10. The impact of enzyme orientation and electrode topology on the catalytic activity of adsorbed redox enzymes

    International Nuclear Information System (INIS)

    It is well established that the structural details of electrodes and their interaction with adsorbed enzyme influences the interfacial electron transfer rate. However, for nanostructured electrodes, it is likely that the structure also impacts on substrate flux near the adsorbed enzymes and thus catalytic activity. Furthermore, for enzymes converting macro-molecular substrates it is possible that the enzyme orientation determines the nature of interactions between the adsorbed enzyme and substrate and therefore catalytic rates. In essence the electrode may impede substrate access to the active site of the enzyme. We have tested these possibilities through studies of the catalytic performance of two enzymes adsorbed on topologically distinct electrode materials. Escherichia coli NrfA, a nitrite reductase, was adsorbed on mesoporous, nanocrystalline SnO2 electrodes. CymA from Shewanella oneidensis MR-1 reduces menaquinone-7 within 200 nm sized liposomes and this reaction was studied with the enzyme adsorbed on SAM modified ultra-flat gold electrodes

  11. Effect of amount of monomer on radiation-induced polymerization of styrene adsorbed on silica gel

    International Nuclear Information System (INIS)

    The effect of amount of monomer on radiation-induced polymerization of styrene adsorbed on silica gel was investigated with the monomer amounting from less than monolayer adsorption to more than the equilibrium adsorption. The rate of graft polymerization and the molecular weight of the polymer changed with the amount of monomer adsorbed on silica gel. Maximum grafting efficiency was obtained at monolayer adsorption. The molecular weigh of graft polymer was higher than that of homopolymer in both radical and cationic polymerizations, and the ratio in molecular weight of graft polymer to that of homopolymer tends to be unity with increasing amount of adsorbed monomer. These results can mainly be explained in terms of the number of initiating species (radical and cation) that change in relation to the amount of adsorbed monomer. Propagation and termination change with amount of adsorbed monomer in relation to the molecular mobility of adsorbed monomer. 9 figures, 2 tables

  12. Solvent cleanup using base-treated silica gel solid adsorbent

    International Nuclear Information System (INIS)

    A solvent cleanup method using silica gel columns treated with either sodium hydroxide (NaOH) or lithium hydroxide (LiOH) has been investigated. Its effectiveness compares favorably with that of traditional wash methods. After treatment with NaOH solution, the gels adsorb HNO3, dibutyl phosphate (DBP), UO22+, Pu4+, various metal-ion fission products, and other species from the solvent. Adsorption mechanisms include neutralization, hydrolysis, polymerization, and precipitation, depending on the species adsorbed. Sodium dibutyl phosphate, which partially distributes to the solvent from the gels, can be stripped with water; the stripping coefficient ranges from 280 to 540. Adsorption rates are diffusion controlled such that temperature effects are relatively small. Recycle of the gels is achieved either by an aqueous elution and recycle sequence or by a thermal treatment method, which may be preferable. Potential advantages of this solvent cleanup method are that (1) some operational problems are avoided and (2) the amount of NaNO3 waste generated per metric ton of nuclear fuel reprocessed would be reduced significantly. 19 references, 6 figures, 12 tables

  13. Heterogeneous radiolysis of HCN adsorbed on a solid surface

    International Nuclear Information System (INIS)

    Hydrogen cyanide is a key molecule for chemical evolution studies because, when it is exposed to different sources of energy, it forms various compounds of biological importance. To understand the role of minerals in chemical evolution, a series of experiments was performed. First, the adsorption capacity of HCN on different surface minerals was studied; the results show that HCN is readily adsorbed onto the solids proposed (zeolite, serpentine, dolomite, and sodium montmorillonite), in particular zeolite and montmorillonite. Second, the radiolysis of HCN adsorbed on olivine (as an example of a mineral surface) was also followed; it was found that the rate of HCN decomposition by gamma irradiation is enhanced in the presence of the solid. The third series of studies show that organic material was produced in high abundance from HCN at high radiation doses. The radiolytic products included gases (CO2, NH4, and CO) and oligomeric materials that release carboxylic acids (succinic, malonic, citric, and tricarballylic acids) and amino acids upon acid hydrolysis. These experiments suggest that minerals could have participated actively in chemical evolution processes.

  14. Adsorbate Electric Fields on a Cryogenic Atom Chip

    CERN Document Server

    Chan, K S; Hufnagel, C; Dumke, R

    2013-01-01

    We investigate the behaviour of electric fields originating from adsorbates deposited on a cryogenic atom chip as it is cooled from room temperature to cryogenic temperature. Using Rydberg electromagnetically induced transparency we measure the field strength versus distance from a 1 mm square of YBCO patterned onto a YSZ chip substrate. We find a localized and stable dipole field at room temperature and attribute it to a saturated layer of chemically adsorbed rubidium atoms on the YBCO. As the chip is cooled towards 83 K we observe a change in sign of the electric field as well as a transition from a localized to a delocalized dipole density. We relate these changes to the onset of physisorption on the chip surface when the van der Waals attraction overcomes the thermal desorption mechanisms. Our findings suggest that, through careful selection of substrate materials, it may be possible to reduce the electric fields caused by atomic adsorption on chips, opening up experiments to controlled Rydberg-surface co...

  15. Mercury(II Removal with Modified Magnetic Chitosan Adsorbents

    Directory of Open Access Journals (Sweden)

    George Z. Kyzas

    2013-05-01

    Full Text Available Two modified chitosan derivatives were prepared in order to compare their adsorption properties for Hg(II removal from aqueous solutions. The one chitosan adsorbent (CS is only cross–linked with glutaraldehyde, while the other (CSm, which is magnetic, is cross-linked with glutaraldehyde and functionalized with magnetic nanoparticles (Fe3O4. Many possible interactions between materials and Hg(II were observed after adsorption and explained via characterization with various techniques (SEM/EDAX, FTIR, XRD, DTG, DTA, VSM, swelling tests. The adsorption evaluation was done studying various parameters as the effect of pH (optimum value 5 for adsorption and 2 for desorption, contact time (fitting to pseudo–first, –second order and Elovich equations, temperature (isotherms at 25, 45, 65 °C, in line with a brief thermodynamic analysis (?G0 0, ?S0 > 0. The maximum adsorption capacity (fitting with Langmuir and Freundlich model of CS and CSm at 25 °C was 145 and 152 mg/g, respectively. The reuse ability of the adsorbents prepared was confirmed with sequential cycles of adsorption-desorption.

  16. Removal of indoor formaldehyde over CMK-8 adsorbents.

    Science.gov (United States)

    Yu, Mi Jin; Kim, Ji Man; Park, Sung Hoon; Jeon, Jong-Ki; Park, Joonhong; Park, Young-Kwon

    2013-04-01

    CMK-8, a mesoporous carbon material, was activated using different methods for the adsorption of low-concentration airborne formaldehyde. KOH and ammonia treatments were used to activate CMK-8. A CMK-8 sample was treated with KOH first followed by an ammonia-treatment at 700 degrees C to determine the effect of a combination of the two treatment methods. The adsorbents prepared were characterized by X-ray diffraction, N2 adsorption-desorption and X-ray photoelectron spectroscopy. The KOH treatment increased the concentration of oxygen functional groups, whereas the ammonia-treatment generated a significant amount of nitrogen functional groups. The formaldehyde adsorption efficiency was highest when both KOH- and ammonia-treatments were applied to CMK-8. The ammonia-treated CMK-8 exhibited higher formaldehyde adsorption ability than the KOH-treated one, whereas non-activated CMK-8 showed the lowest formaldehyde adsorption efficiency. The number of nitrogen functional groups and the specific surface area appeared to significantly affect the formaldehyde adsorption capability of the adsorbents, whereas oxygen functional groups played a less important role. PMID:23763174

  17. Structural Properties of Polystyrene Adsorbed onto a Solid Surface

    Science.gov (United States)

    Tatek, Yergou; Tsige, Mesfin

    2010-03-01

    The understanding of the structural properties of polymer layers adsorbed onto a solid surface is of paramount importance in a wide variety of technical applications. For instance, an area where surface coating is important is the solar cell technology. It has been shown that the performance of solar cells can be greatly enhanced by polymer coating. In the present work we are studying the local conformation of chains in a thin film of polystyrene (PS) adsorbed on a solid substrate by using atomistically detailed simulations. The simulations are carried out by using the readily available and massively parallel molecular dynamics code known as LAMMPS. In particular, a special emphasis is given to the density and orientation of side chains (which consist of phenyl and methylene groups) at solid/polymer and air/polymer interfaces. Three types of substrate were used in our study: ?-quartz, graphite and amorphous silica. Moreover, we investigated the adsorption of PS chains of different tacticity. Our preliminary results show the presence of a peak of concentration of phenyl rings near the substrate/PS interface. This is tantamount to the existence of a local ordering in that region. Rings at both interfaces tend to point outward the film whereas rings away from the interfaces have no preferred orientation. Our results are in a large part in good agreement with previous experimental and simulation results.

  18. Structural properties of atactic polystyrene adsorbed onto solid surfaces

    Science.gov (United States)

    Tatek, Yergou B.; Tsige, Mesfin

    2011-11-01

    In the present work, we are studying the local conformation of chains in a thin film of polystyrene adsorbed on a solid substrate by using atomistically detailed simulations. The simulations are carried out by using the readily available and massively parallel molecular dynamics code known as LAMMPS. In particular, a special emphasis is given to the density and orientation of side chains (which consist of phenyl groups and methylene units) at solid/polymer and polymer/vacuum interfaces. Three types of substrates were used in our study: ?-quartz, graphite, and amorphous silica. Our investigation was restricted to atactic polystyrene. Our results show that the density and structural properties of side chains depend on the type of surface. An excess of phenyl rings is observed near the ?-quartz substrate while the film adsorbed on graphite is depleted in C6H5. Moreover, the orientation of the rings and methylene units on the substrate/film interface show a strong dependence on the type of the substrate, while the rings at the film/vacuum interface show a marked tendency to point outward, away from the film. The results we obtained are in a large part in good agreement with previous experimental and simulation results.

  19. Optical emissions from oxygen atom reactions with adsorbates

    Science.gov (United States)

    Oakes, David B.; Fraser, Mark E.; Gauthier-Beals, Mitzi; Holtzclaw, Karl W.; Malonson, Mark; Gelb, Alan H.

    1992-12-01

    Although most optical materials are inert to the ambient low earth orbit environment, high velocity oxygen atoms will react with adsorbates to produce optical emissions from the ultraviolet into the infrared. The adsorbates arise from chemical releases or outgassing from the spacecraft itself. We have been investigating kinetic and spectral aspects of these phenomenon by direct observation of the 0.2 to 13 micrometers chemiluminescence from the interaction of a fast atomic oxygen beam with a continuously dosed surface. The dosing gases include fuels, combustion products and outgassed species such as unsymmetrical dimethylhydrazine (UDMH), NO, H2O and CO. The surface studied include gold and magnesium fluoride. In order to relate the results to actual spacecraft conditions these phenomena have been explored as a function of O atom velocity, dosant flux and substrate temperature. UDMH dosed surfaces exhibit spectra typical (wavelength and intensity) of carbonaceous surfaces. The primary emitters are CO, CO2, and OH. H2O dosed surfaces are dominated by OH and /or H2O emission while CO dosed surfaces are dominated by CO and CO2 emissions. The nitric oxide dosed surface produces a glow from 0.4 to 5.4 micrometers due to NO2* continuum emission. The emission was observed to increase by a factor of two upon cooling the surface from 20 degree(s)C to -35 degree(s)C.

  20. Electron emission from thoriated tungsten with adsorbed cesium

    International Nuclear Information System (INIS)

    Development of high-efficiency, long-life converters stands as one of the most important goals in thermionic energy conversion (TEC). Such an accomplishment requires low-work-function emitters and collectors for effective electron emission and collection. In most conventional converters cesium adsorbed on electrodes reduces work functions - and ionized between electrodes neutralizes space charge and diminishes interelectrode losses. So measurement of electron emission through adsorbed cesium ranks high in the evaluation of a potential TEC-electrode material. The research reported here is of this nature. Results comprise electron-emission characteristics for cesiated tungsten alloys, containing one or, two percent thoria, determine by the plasma-anode technique originated by Marchuk, Houston, DeSteese, Kidd and Manda employed similar methods but advanced the apparatus in various ways. The Marchuk tube provides a cesium plasma to collect electrons thermionically emitted from a small wire loop of sample material. This probe operates at a few volts negative relative to the potential of the cesium plasma that immerses it

  1. Purification of Sardinella sp., Oil: Centrifugation and Bentonite Adsorbent

    Directory of Open Access Journals (Sweden)

    S.H. Suseno

    2014-01-01

    Full Text Available Centrifugation and purification using adsorbents is one example of a fish oil refining techniques applied to reduce impurities of fish oil. The study aimed to determine the sardine oil quality before treatment, to determine yield of fish oil after centrifugation treatment and to determine the influence of centrifugation speed and bentonite concentration on sardine oil quality. Factorial design with two factors was used in this study. Level of free fatty acid and peroxide value before purification was 35.53% and 170 mEq/kg. Yield of fish oil after centrifugation treatment has been ranged from 17.42±3.56 to 76.33±0.21%. The best treatment which could reduce the peroxide value and total oxidation was a treatment with centrifugation speed at 6500 rpm and bentonite concentration at 3%. Peroxide value and total oxidation of its treatment was 25.00±0.00 and 51.43±0.01 mEq/kg. The lowest value of p-anisidine was 1.29±0.05 mEq/kg and its value could be found in a treatment with centrifugation speed at 4500 rpm and bentonite concentration at 5%. The level of free fatty acid after purification process was ranged from 27.35 to 34.69%. Oil clarity tended to increase with the increase of centrifugation speed and adsorbent concentration.

  2. Treatment of uranium mining and milling wastewater using biological adsorbents

    International Nuclear Information System (INIS)

    Selected samples of waste microbial biomass originating from various industrial fermentation processes and biological treatment plants have been screened for biosorbent properties in conjunction with uranium, thorium and radium in aqueous solutions. Biosorption isotherms were used for the evaluation of biosorptive uptake capacity of the biomass. The biomass was also compared to synthetic adsorbents such as activated carbon. Determined uranium, thorium and radium biosorption isotherms were independent of the initial solution concentrations. Solution pH affected uptake. Rhizopus arrhizus at pH 4 exhibited the highest uranium and thorium biosorptive uptake capacity in excess of 180 Mg/g. It removed about 2.5 and 3.3 times more uranium than the ion exchange resin and activated carbon tested. Penicillium chrysogenum adsorbed 50000 pCi/g radium at pH 7 and at an equilibrium radium concentration of 1000 pCi/L. The most effective biomass types studied exhibited removals in excess of 99% of the radium in solution

  3. Home-made carbonaceous adsorbents for the iodine filter

    International Nuclear Information System (INIS)

    Assuming, that at the moment, an activated charcoal is the most widely used adsorbent in off-gas cleaning systems for elemental iodine removal, it was analyzed how to improve the adsorption properties of this filter material for removing the organic iodine compounds, especially in the presence of high relative humidity. Three different indigenous activated charcoals were selected for studies: two kinds of charcoal, designated as type A and N, as well as the charcoals used for flue gas desulfurization, as the third type S. These charcoals were impregnated with tin iodide (SnI2), potassium iodide (KI) and triethylenediamine (TEDA). Considering the results of the laboratory tests of the efficiency methyl iodide retention by the impregnated charcoals, it was concluded, that the carbonaceous adsorbent containing 1+1.5% KI showed efficient retention of the methyl iodide (CH3I), compared with, for example, foreign activated charcoals, as, NORIT-CGI 1% KI (West Germany) and GA-1 0.5% KI (Czechoslovakia). (author)

  4. CO2 electrochemical reduction via adsorbed halide anions

    Science.gov (United States)

    Ogura, Kotaro; Salazar-Villalpando, Maria D.

    2011-01-01

    The electrochemical reduction of CO2 was studied utilizing halide ions as electrolytes, specifically, aqueous solutions of KCl, KBr, KI. Electrochemical experiments were carried out in a laboratory-made, divided H-type cell. The working electrode was a copper mesh, while the counter and reference electrodes were a Pt wire and an Ag/AgCl electrode, respectively. The results of our work suggest a reaction mechanism for the electrochemical reduction of CO2 where the presence of Cu-X as the catalytic layer facilitates the electron transfer from the electrode to CO2. Electron-transfer to CO2 may occur via the X- ad(Br-, Cl-, I-)-C bond, which is formed by the electron flow from the specifically adsorbed halide anion to the vacant orbital of CO2. The stronger the adsorption of the halide anion to the electrode, the more strongly CO2 is restrained, resulting in higher CO2 reduction current. Furthermore, it is suggested that specifically adsorbed halide anions could suppress the adsorption of protons; leading to a higher hydrogen overvoltage. These effects may synergistically mitigate the over potential necessary for CO2 reduction, and thus increase the rate of electrochemical CO2 reduction.

  5. Membrane adsorbers comprising grafted glycopolymers for targeted lectin binding

    Science.gov (United States)

    Chenette, Heather C.S.; Husson, Scott M.

    2014-01-01

    This work details the design and testing of affinity membrane adsorbers for lectin purifications that incorporate glucose-containing glycopolymers. It is the selective interaction between the sugar residues of the glycopolymer and the complementary carbohydrate-binding domain of the lectin that provides the basis for the isolation and purification of lectins from complex biological media. The design approach used in these studies was to graft glycopolymer ‘tentacles’ from macroporous regenerated cellulose membranes by atom transfer radical polymerization. As shown in earlier studies, this design approach can be used to prepare high-productivity membrane adsorbers. The model lectin, concanavalin A (conA), was used to evaluate membrane performance in bind-and-elute purification, using a low molecular weight sugar for elution. The membrane capacity for binding conA was measured at equilibrium and under dynamic conditions using flow rates of 0.1 and 1.0 mL/min. The first Damkohler number was estimated to relate the adsorption rate to the convective mass transport rate through the membrane bed. It was used to assess whether adsorption kinetics or mass transport contributed the primary limitation to conA binding. Analyses indicate that this system is not limited by the accessibility of the binding sites, but by the inherent rate of adsorption of conA onto the glycopolymer. PMID:25866416

  6. Removal of nickel from wastewater using an agricultural adsorbent

    Scientific Electronic Library Online (English)

    Krishnie, Moodley; Ruella, Singh; Evans T, Musapatika; Maurice S, Onyango; Aoyi, Ochieng.

    2011-01-01

    Full Text Available Chemical wastewater streams may contain toxic compounds which are non-biodegradable, and therefore require advanced treatment techniques such as adsorption. However, application of adsorption processes is often limited by the cost of adsorbents. In this study, the adsorption capacity of a low-cost a [...] dsorbent (pine sawdust) was investigated by treating wastewater containing nickel (II) and other heavy metal ions. Results were analysed using response surface methodology and a factorial design was employed to determine the interactive effects of the various factors on the adsorption capacity. Furthermore, Langmuir and Freundlich adsorption isotherms were fitted to experimental data to characterise the adsorption of the nickel ions by the pine sawdust. As a result, the highest adsorption capacity was attained at the combined effect of low adsorbent dose, high pH and high initial concentration. On the other hand, the Freundlich isotherm fitted the experimental data better than the Langmuir isotherm. Results of this study indicate that the use of pine sawdust could be a promising solution to the elimination of nickel ions from multi-component aqueous solutions.

  7. Potential of single and double-combined adsorbents in removing chromium from an industrial wastewater

    OpenAIRE

    Mousavi S.F.; Rostamian R.; Aghakhani A.

    2014-01-01

    Nowadays, there is much attention in using low-cost methods for removing heavy metals’ pollution from wastewaters. In this research, the ability of different adsorbents including zeolite, peat, activated carbon, cationic resin and anionic resin (in single and double-combined forms) in decreasing Cr(III) and Cr(VI) concentration to below the legal limits from an industrial wastewater was investigated. The results showed that for single-adsorbent treatments, all adsorbents were more effective...

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

    International Nuclear Information System (INIS)

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

  9. Study on the performance of adsorbing uranium by attapulgite clay and its application

    International Nuclear Information System (INIS)

    The author studies the performances of acidity, adsorption rate, adsorptive reaction heat content, adsorptive capacity of adsorbing uranium by attapulgite clay. The optimum condition for adsorbing uranium is determined. It get a excellent condition for adsorbing uranium that uranium-bearing waste water is treated by dynamic method (exchange pole method), and the removing rate is above 99.95%. The residual concentration of uranium in discharge waste water reaches the state specified discharge standard (0.005 mg/l)

  10. Theoretical and experimental investigations of an adsorption heat pump with heat transfer between two adsorbers

    OpenAIRE

    Schawe, Dirk

    2001-01-01

    Two thermally powered and quasi-continuously working heat pumps with two adsorbers effected by the principles of adsorption are investigated. In contrast to adsorption heat pumps with a single adsorber these systems deal with a multiple heat and mass transformation between two different adsorptive materials to obtain higher performances. The adsorptive characteristics of both adsorbents should be designed in a way that the heat released from both the desorption-cycle as well as the adsorption...

  11. Simple model for scanning tunneling spectroscopy of noble metal surfaces with adsorbed Kondo impurities

    OpenAIRE

    Merino, J.; Gunnarsson, O.

    2003-01-01

    A simple model is introduced to describe conductance measurements between a scanning tunneling microscope (STM) tip and a noble metal surface with adsorbed transition metal atoms which display the Kondo effect. The model assumes a realistic parameterization of the potential created by the surface and a d3z2-r2 orbital for the description of the adsorbate. Fano lineshapes associated with the Kondo resonance are found to be sensitive to details of the adsorbate-substrate inter...

  12. Processing method for adsorbent of radioactive nuclide and radioactive liquid waste

    International Nuclear Information System (INIS)

    The adsorbent of the present invention comprises activated carbon having a specific surface area of greater than 600m2/g and aminomethyl phosphorate type functional groups applied on the surface thereof. TRU nuclides can be selectively adsorbed from the liquid wastes containing radioactive nuclides by using the adsorber of the present invention, thereby enabling to easily process radioactive liquid wastes, which was difficult to be processed so far. (T.M.)

  13. Technico-Economical Evaluation of CO2 Transport in an Adsorbed Phase

    OpenAIRE

    Mildred Lemus Perez; Manuel Rodriguez Susa; Mario Pellerano; Arnaud Delebarre

    2012-01-01

    This work considers the possibility to transport CO2 in an adsorbed phase and analyzes its cost as a function of transported quantities, transport conditions and transportation means. CO2 adsorption capacities of 6 different adsorbents, comprising 4 activated carbons and 2 zeolites, were empirically evaluated in a given range of pressure and temperature. The adsorbent with the highest mass adsorption capacity (AC1), as well as another sorbent desc...

  14. Kaolin-Carbon Adsorbents for Carotene Removal of Red Palm Oil.

    Science.gov (United States)

    Hussein, Mohd Zobir Bin; Kuang, Dzulkefly; Zainal, Zulkarnain; Teck, Tan Kian

    2001-03-01

    Kaolin-carbon adsorbents were prepared with and without sulfuric acid pretreatment followed by activation-carbonization at 500 degrees C. The total surface area of the resulting kaolin-carbon adsorbents was found to be decreased with the increase in kaolin loading. Sulfuric acid pretreatment of the precursor prior to the carbonization-activation processes resulted in the enhancement of total surface area but reduced the micropore surface area of the resulting adsorbents. At the same time, this improved carotene adsorption capacity from red palm oil. However, recovery of carotene from the carotene-adsorbed adsorbent is only improved when the acid pretreatment of the precursor was done at a high loading percentage of activated carbon. Similarly, the peroxide value (PV) increased. A maximum removal of carotene from red palm oil was obtained at 20% kaolin loading for both adsorbents prepared with and without sulfuric acid pretreatment with about 45 and 65% carotene removal, respectively, from a 30-ppm solution. This indicates that pretreatment with sulfuric acid, prior to the activation-carbonization process, increased the carotene uptake by the resulting adsorbent. However, a further increase in the kaolin loading resulted in the decrease of carotene removal. About 3-4% of carotene adsorbed can be recovered from both types of adsorbents under optimum condition, in which the percentage recovered decreased with the increase in kaolin loading. On the other hand, the PV increased with kaolin loading at around 54-64 mEq/kg for both types of adsorbents. It was also found that carotene uptake by the adsorbents is high if the adsorbent contains a high percentage of activated carbon. Similarly, carotene recovery is high and less oxidation can be observed, as indicated by the lower PV value. Copyright 2001 Academic Press. PMID:11237447

  15. A device for taking test-samples from a gas adsorbing cell

    International Nuclear Information System (INIS)

    The invention relates to a device for taking samples for the periodical checking of gas adsorbing cells. The adsorbing cell comprises an enclosure provided with a pair of spaced perforated sheets adapted to receive an adsorbent material therebetween, a sample-holder also adapted to be filled with the adsorbent material and provided with perforated opposed extremities, and means for removably mounting said sample holder between the sheets, so that a representative gas portion flowing through the cell also flow through the sample holder. The invention can be applied to gas treatment systems in nuclear power generators

  16. Biodegradable metal adsorbent synthesized by graft polymerization onto nonwoven cotton fabric

    International Nuclear Information System (INIS)

    A fibrous adsorbent for Hg ions was synthesized by radiation-induced emulsion graft polymerization of glycidyl methacrylate (GMA) onto a nonwoven cotton fabric and subsequent chemical modification. The optimal pre-irradiation dose for initiation of the graft polymerization of GMA, which minimized the effects of radiation damage on the mechanical strength of the nonwoven cotton fabric, was found to be 10 kGy. The GMA-grafted nonwoven cotton fabric was subsequently modified with ethylenediamine (EDA) or diethylenetriamine (DETA) to obtain a Hg adsorbent. The resulting amine-type adsorbents were evaluated for batch and continuous adsorption of Hg. In batch adsorption, the distribution coefficients of Hg reached 1.9x105 and 1.0x105 for EDA- and DETA-type adsorbents, respectively. A column packed with EDA-type adsorbent removed Hg from 1.8 ppm Hg solution at a space velocity of 100 h-1, which corresponds to 16,000 times the volume of the packed adsorbent. The adsorbed Hg on the EDA-type adsorbent could be completely eluted by 1 M HCl solution. A microbial oxidative degradation test revealed that the EDA-type adsorbent is biodegradable.

  17. Electronic properties of adsorbates and clean surfaces of metals and semiconductors

    International Nuclear Information System (INIS)

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

  18. Elimination of dyes from aqueous solutions using iron oxides and chitosan as adsorbents: a comparative study

    OpenAIRE

    Silvina Pirillo; Viviana Pedroni; Elsa Rueda; María Luján Ferreira

    2009-01-01

    This work investigates the adsorption of Alizarin, Eriochrome Blue Black R and Fluorescein using chitosan, goethite and magnetite as adsorbents. For Alizarin, the best adsorbent is chitosan with a Langmuir parameter of 15.8 mmol dye/g adsorbent. For Eriochrome Blue Black R only 1.94 mmol dye/g chitosan is adsorbed. Langmuir parameters for the Alizarin adsorption on both iron oxides display one or two orders of magnitude lower than for chitosan and two orders of magnitude lower in the case of ...

  19. Adsorption properties of Cs by inorganic adsorbents in sodium chloride solution

    International Nuclear Information System (INIS)

    Adsorption of Cs with five types of inorganic adsorbents (CST (Crystalline SilicoTitanate) powder, CST grain, synthetic mordenite powder, synthetic mordenite grain, and natural mordenite)) was carried out by batch methods in the aqueous solution of NaCl at room temperature, respectively. The concentration of Cs after the batch experiments decreased compared with the initial concentration of Cs when the ratio of the solution volume (ml) to the amount of the adsorbent (g) was 100 ml/g, and it was confirmed that the adsorbents used in the present study adsorbed Cs+ ion in the presence of Na+ and Cl- ions. (author)

  20. Detection of adsorbed explosive molecules using thermal response of suspended microfabricated bridges

    DEFF Research Database (Denmark)

    Yi, Dechang; Greve, Anders

    2008-01-01

    Here we present a thermophysical technique that is capable of differentiating vapor phase adsorbed explosives from nonexplosives and is additionally capable of differentiating individual species of common explosive vapors. This technique utilizes pairs of suspended microfabricated silicon bridges that can be heated in a controlled fashion. The differential thermal response of the bridges with and without adsorbed explosive vapor shows unique and reproducible characteristics depending on the nature of the adsorbed explosives. The tunable heating rate method described here is capable of providing unique signals for subnanogram quantities of adsorbed explosives within 50 ms. (C) 2008 American Institute of Physics.

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

    International Nuclear Information System (INIS)

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

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

    Science.gov (United States)

    Okamoto, Jiro; Sugo, Takanobu; Fujiwara, Kunio; Sekiguchi, Hideaki

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

  3. Comparison of treated laterite as arsenic adsorbent from different locations and performance of best filter under field conditions.

    Science.gov (United States)

    Maiti, Abhijit; Thakur, Barun Kumar; Basu, Jayanta Kumar; De, Sirshendu

    2013-11-15

    Arsenic pollution in groundwater is a worldwide concern due to its chronic effects on human health. Numerous studies have been carried out to obtain cost-effective arsenic removal method. Adsorption using natural materials or its treated forms is found to be cost-effective technology. Raw laterite (RL) or its treated form (TL) is studied recently as arsenic adsorbent for aqueous system. Laterite composition varies with geographical location and extent of lateritization. The study on effects of arsenic adsorption with varying composition of laterite is not explored yet. Four laterite samples with different compositions are examined to remove arsenic from water. These laterite samples are activated using an optimized acid followed by base treatment method in order to determine the effects of RL composition on arsenic adsorption behavior of TL. Higher iron and aluminum containing RL samples show higher arsenic adsorption behavior. Similarly, TL obtained from higher iron and aluminum containing RL sample shows the higher specific surface area (130-180 m(2) g(-1)) and pore volume (0.28-0.35 mL g(-1)). Two household filters using TL are deployed in arsenic affected area of Barasat, 24 Parganas (N), West Bengal, India and their performance is monitored for about a year. PMID:22785008

  4. Dry washing in biodiesel purification: a comparative study of adsorbents

    Scientific Electronic Library Online (English)

    Candice Schmitt, Faccini; Michele Espinosa da, Cunha; Maria Silvana Aranda, Moraes; Laiza C, Krause; Márcia C, Manique; Maria Regina A, Rodrigues; Edilson V, Benvenutti; Elina B, Caramão.

    2011-03-01

    Full Text Available O objetivo deste trabalho é comparar a eficiência de diferentes adsorventes na purificação de biodiesel produzido por transesterificação alcalina do óleo de soja (metanol/KOH). As metodologias propostas foram baseadas na utilização de Magnesol®, sílica, Amberlite BD10 DRY® e Purolite PD 206® como ad [...] sorventes e foram desenvolvidas por adsorção a 65 ºC. A eficiência de cada adsorvente foi medida através do teor residual de potássio, álcool, água e sabão, dissolvidos no biodiesel purificado. Como resultado, observamos que Magnesol® e sílica apresentaram melhores propriedades de adsorção que Amberlite BD10 DRY® e Purolite PD 206®, especialmente para remover sabão, glicerina livre e ligada e potássio. Em comparação com a lavagem ácida convencional, estas matrizes foram consideradas adequadas para a remoção de espécies contaminantes inorgânicas e orgânicas do biodiesel. Os principais resultados encontrados para estes dois adsorventes (Magnesol® 1% e sílica 2%) foram valores abaixo de 0,17 mg KOH g-1 de acidez, 1 mg kg-1 de potássio, 61 ppm de sabão, 500 mg kg-1 de água, 0,22% de metanol, 0,30% de glicerina livre e 0,03% de glicerina ligada Abstract in english The purpose of this work is to compare the efficiency of different adsorbents in the purification of biodiesel produced by alkaline transesterification of soybean oil (Methanol/KOH). The proposed methodologies were based on the use of Magnesol®, silica, Amberlite BD10 DRY® and Purolite PD 206® as ad [...] sorbents and were developed by adsorption at 65 ºC. The response of each adsorbent was measured through the residual potassium, alcohol, water and soaps dissolved in the purified biodiesel. As a result, we observe that Magnesol® and silica showed better adsorption properties than Amberlite BD10 DRY® and Purolite PD 206®, especially for removing soap, free and bonded glycerol and potassium. In comparison to the conventional acid water washing, these matrices were found to be equally appropriate for the removal of inorganic and organic contaminant species from biodiesel. The main results found for these two adsorbents (Magnesol® 1% and silica 2%) were values below 0.17 mg KOH g-1 for acid number, 1 mg kg-1 of K, 61 ppm of soap, 500 mg kg-1 of water, 0.22% of methanol and 0.03% of free glycerol

  5. Oral solid gentamicin preparation using emulsifier and adsorbent.

    Science.gov (United States)

    Ito, Yukako; Kusawake, Tomohiro; Ishida, Makoto; Tawa, Riichi; Shibata, Nobuhito; Takada, Kanji

    2005-06-20

    Oral gentamicin (GM) therapy has been challenged by formulating GM in oral solid preparation. GM was dispersed with a surfactant used for the self-microemulsifying drug delivery system (SMEDDS), PEG-8 caprylic/capric glycerides (Labrasol), and the mixture was solidified with several kinds of adsorbents. The used adsorbents were microporous calcium silicate (Florite RE), magnesium alminometa silicate (Neusilin US2), and silicon dioxide (Sylysia 320). In vitro release study showed that the percentage released of GM from each preparation per 2 h was 99.8+/-0.06% for Florite RE 10 mg, 96.7+/-1.16% for Florite RE 20 mg, 98.3+/-0.32% for Neusilin US2, and 94.4+/-0.23% for Sylysia 320. The T50% values were 0.35+/-0.05 h for Florite RE 10 mg, 0.34+/-0.03 h for Florite RE 20 mg, 0.26+/-0.03 h for Neusilin US2, and 0.15+/-0.01 h for Sylysia 320. The in vivo rat absorption study showed that Florite RE 10 mg preparation had the highest C(max) (2.14+/-0.67 microg/ml) and AUC (4.74+/-1.21 microg h/ml). Other preparations had C(max) and AUC of 0.69+/-0.10 microg/ml and 1.56+/-0.43 microg h/ml for Florite RE 20 mg, 1.07+/-0.31 microg/ml and 1.80+/-0.33 microg h/ml for Neusilin US2, and 0.99+/-0.21 microg/ml and 1.77+/-0.50 micorg h/ml for Sylysia 320, respectively. The bioavailability (BA) of GM from the microporous calcium silicate preparation, Florite RE 10 mg, was 14.1% in rats, derived by comparing the AUC obtained after intravenous injection of GM, 1.0 mg/kg, to another group of rats. The microporous calcium silicate preparation using Florite RE 10 mg was evaluated in dogs after oral administration in an enteric capsule, Eudragit S100 (50 mg/dog). High plasma GM levels were obtained (i.e., the C(max) was 1.26+/-0.20 microg/ml and the AUC was 2.59+/-0.33 microg h/ml). These results suggest that an adsorbent system is useful as an oral solid delivery system of poorly absorbable drugs such as GM. PMID:15908031

  6. Remobilization of toxic heavy metals adsorbed to bacterial wall-clay composites.

    OpenAIRE

    Flemming, C. A.; Ferris, F. G.; Beveridge, T. J.; Bailey, G. W.

    1990-01-01

    Significant quantities of Ag(I), Cu(II), and Cr(III) were bound to isolated Bacillus subtilis 168 walls, Escherichia coli K-12 envelopes, kaolinite and smectite clays, and the corresponding organic material-clay aggregates (1:1, wt/wt). These sorbed metals were leached with HNO3, Ca(NO3)2, EDTA, fulvic acid, and lysozyme at several concentrations over 48 h at room temperature. The remobilization of the sorbed metals depended on the physical properties of the organic and clay surfaces and on t...

  7. Lead Removal from water by low cost adsorbents: a review

    International Nuclear Information System (INIS)

    Lead is known to be toxic for human's body systems i.e. nervous, digestive and skeleton system even if it is present in low levels. The rapidly increasing population is appending many problems concerning water pollution. The presence of lead metal in drinking water is of special concern because of its persistence and toxicity. In this review paper lead toxicity, its contamination in water and the effects of various factors on adsorption of lead, reaction kinetics, nature of link between lead and surface of media are described. The general prominence has been given on the utilization of different agricultural, industrial wastes and low cost synthetic oxides as adsorbents for the removal of poisonous lead from water. (author)

  8. Infrared overtone spectroscopy of adsorbed hydrogen in MOF-5

    Science.gov (United States)

    FitzGerald, Stephen A.; Nelson, Jocienne N.; Gilmour, Elizabeth; Rowsell, Jesse L. C.

    2015-01-01

    Overtone spectroscopy is used to observe the rovibrational spectra of the hydrogen isotopologues H2, HD, and D2 adsorbed in the metal-organic framework known as MOF-5. It is shown that the overtone spectrum facilitates the identification of hydrogen modes which are obscured in the fundamental region by the presence of MOF-5 features. Further, the overtone spectrum of H2 at the primary adsorption site is greatly enhanced relative to other sites, and thus ambiguities about feature assignment can be avoided. The frequency (wavenumber) of the overtone modes are in good agreement with a Buckingham perturbative model while the relative intensity of the Q2 (0) pure vibrational mode is found to be anomalously large, most likely arising through mode coupling to the MOF-5 framework.

  9. Challenge to high-activity-level water treatment by adsorbents

    International Nuclear Information System (INIS)

    There are over 280,000 tonnes of contaminated water in the damaged Fukushima Daiichi Nuclear Plant site in various tanks and barges and a large amount of contaminated water is now producing at the rate of several tonnes/day owing to inevitable cooling of the reactor cores. SARRY (Simplified Active Water Retrieve and Recovery System) and ALPS (Advanced Liquid Processing System) are installed to remove Cs and multi-elements respectively utilizing ion exchangers (zeolite, crystalline silicon titanate, and metal ferrocyanides) from contaminated water. The author continues efforts to find effective and selective adsorbents for Cs and Sr by measuring partition data, adsorption isotherms and adsorption rate referring with chemical structure elucidated from X-ray diffraction and SEM techniques. The obtained data are presented. (S. Ohno)

  10. Enhanced self-diffusion of adsorbed methanol in silica aerogel

    Science.gov (United States)

    Lee, Jeongseop A.; Mounce, A. M.; Oh, Sangwon; Zimmerman, A. M.; Halperin, W. P.

    2014-11-01

    Molecular transport of a two-component system of liquid and vapor in a porous medium can be anomalously increased owing to fast exchange between the two phases [Phys. Rev. Lett. 63, 43 (1989), 10.1103/PhysRevLett.63.43]. We have investigated this phenomenon measuring the self-diffusion coefficient of methanol adsorbed in a 98% porosity aerogel using nuclear magnetic resonance field gradient techniques. We found enhancement of several orders of magnitude from which we determined the ballistic mean-free path in the vapor phase. We have grown globally uniform anisotropic aerogels and applied the diffusion measurements to characterize the anisotropy. Our results are important for understanding the novel properties of superfluid 3He confined within an aerogel framework and for application to other physical systems.

  11. Vapor pressure of plutonium carbide adsorbed on graphite

    International Nuclear Information System (INIS)

    An investigation was conducted to obtain data needed to make realistic estimates of plutonium contamination in the primary coolant system in High Temperature Gas-Cooled Reactors (HTGRs). The vapor pressure of plutonium over plutonium sesquicarbide (Pu2C3) adsorbed on the surface of H-451 graphite was found to be defined by adsorption isotherms at test temperatures of 1000, 1200, and 14000C. The vapor pressures at low concentrations of Pu2C3 on the surface of the graphite were up to three orders of magnitude below that of pure Pu2C3 at a given temperature. The heat of adsorption increases with decreasing Pu2C3 surface coverage with the measured value at 0.05 ?mol Pu2C3/m2 being 107.9 kcal/mol. The Pu2C3 concentration required for monolayer surface coverage on the graphite was found to be 3.27 ?mol/m2

  12. Excitation spectrum of hydrogen adsorbed to carbon nanotubes

    CERN Document Server

    Renker, B; Schweiss, P; Lebedkin, S; Hennrich, F

    2003-01-01

    We have studied the microscopic dynamics of hydrogen adsorbed to bundles of single walled carbon nanotubes using inelastic neutron scattering. Evidence is obtained for much higher storage capacities in chemically treated compared to as prepared material. This indicates an additional adsorption layer inside the tubes. Well pronounced excitations in the H2 spectrum at low energies confirm this conclusion. The desorption of hydrogen is monitored in real time as a function of temperature. Hydrogen storage is highly stable below 150 K in agreement with the harmonic evolution of the hydrogen spectrum, which indicates a strong binding potential. Above 200 K hydrogen can be released in a controlled way by simple heating. The excitation spectrum changes significantly during the release. Remnants of hydrogen persist up to 400 K.

  13. Application of Henry's Law for Binding Energies of Adsorbed Hydrogen

    Science.gov (United States)

    Gillespie, Andrew; Dohnke, Elmar; Stalla, David; Sweany, Mark; Pfeifer, Peter

    2015-03-01

    The method of isosteres is the simplest method used to calculate the differential enthalpy of adsorption. However, it is incredibly sensitive to the choice of model and respective fitting parameters. For a set of isotherms measured on a specific sample, most models converge upon a similar value at high coverage, but are inconsistent in the low pressure regime. In this talk, we investigate the application of various models for localized and mobile adsorption at low pressures in order to obtain binding energy of hydrogen to the adsorbent surface. Henry's Law analysis of the Langmuir Model of adsorption yield binding energies in excellent agreement with those obtained from the Clausius Clapeyron relation. Work supported by DOE-EERE, Award No. DE-FG36-08GO18142.

  14. Gamma radiation-polymerized methacrylates used as heavy metals adsorbents

    International Nuclear Information System (INIS)

    Heavy metal removal from aqueous solution is a priority research area since the actual methods are costly and a major drawback is the large amounts of sludge generated when applying traditional techniques. Adsorption is a physiochemical wastewater treatment process, which is gaining prominence as a means of producing high quality effluents, which are low in metal ion concentrations. The development of inexpensive adsorbents for the treatment of wastewater is an important area in environmental sciences. In this work we describe some of the physical and chemical phenomena that take place in the polymerization of methacrylates when gamma radiation is used. We explain how polymeric material characterization equipment are used for obtaining information regarding the material properties. Then we explain how the new polymeric material obtained can be use for the wastewater treatment. Finally, a comparison in the heavy metal removal from aqueous solution with other sorbent materials is presented. (Author)

  15. In-situ fabrication of MoSi2/SiC-Mo2C gradient anti-oxidation coating on Mo substrate and the crucial effect of Mo2C barrier layer at high temperature

    Science.gov (United States)

    Liu, Jun; Gong, Qianming; Shao, Yang; Zhuang, Daming; Liang, Ji

    2014-07-01

    MoSi2/SiC-Mo2C gradient coating on molybdenum was in situ prepared with pack cementation process by two steps: (1) carburizing with graphite powder to obtain a Mo2C layer on Mo substrate, and (2) siliconizing with Si powder to get a composite MoSi2/SiC layer on the upper part of Mo2C layer. The microstructure and elemental distribution in the coating were investigated with scanning electron microscopy (SEM), back scattered electron (BSE), energy dispersive spectroscopy (EDS), electron probe microanalysis (EPMA) and X-ray diffraction (XRD). Cyclic oxidation tests (at 500 °C, 1200 °C, 1400 °C and 1600 °C) demonstrated excellent oxidation resistance for the gradient composite coating and the mass loss was only 0.23% in 60 min at 1600 °C. XRD, EPMA, thermal dynamic and phase diagram analyses indicated that the Mo2C barrier layer played the key role in slowing down the diffusion of C and Si toward inner Mo substrate at high temperature and principally this contributed to the excellent anti-oxidation for Mo besides the outer MoSi2/SiC composite layer.

  16. In-situ fabrication of MoSi2/SiC–Mo2C gradient anti-oxidation coating on Mo substrate and the crucial effect of Mo2C barrier layer at high temperature

    International Nuclear Information System (INIS)

    MoSi2/SiC–Mo2C gradient coating on molybdenum was in situ prepared with pack cementation process by two steps: (1) carburizing with graphite powder to obtain a Mo2C layer on Mo substrate, and (2) siliconizing with Si powder to get a composite MoSi2/SiC layer on the upper part of Mo2C layer. The microstructure and elemental distribution in the coating were investigated with scanning electron microscopy (SEM), backscattered electron (BSE), energy dispersive spectroscopy (EDS), electron probe microanalysis (EPMA) and X-ray diffraction (XRD). Cyclic oxidation tests (at 500 °C, 1200 °C, 1400 °C and 1600 °C) demonstrated excellent oxidation resistance for the gradient composite coating and the mass loss was only 0.23% in 60 min at 1600 °C. XRD, EPMA, thermal dynamic and phase diagram analyses indicated that the Mo2C barrier layer played the key role in slowing down the diffusion of C and Si toward inner Mo substrate at high temperature and principally this contributed to the excellent anti-oxidation for Mo besides the outer MoSi2/SiC composite layer.

  17. In-situ fabrication of MoSi{sub 2}/SiC–Mo{sub 2}C gradient anti-oxidation coating on Mo substrate and the crucial effect of Mo{sub 2}C barrier layer at high temperature

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Jun [School of Materials Science and Engineering, Tsinghua University, Beijing 100084 (China); Key Laboratory for Advanced Materials Processing Technology, Ministry of Education, Beijing 100084 (China); State Key Laboratory of New Ceramics and Fine Processing, Beijing 100084 (China); Gong, Qianming, E-mail: gongqianming@mail.tsinghua.edu.cn [School of Materials Science and Engineering, Tsinghua University, Beijing 100084 (China); Key Laboratory for Advanced Materials Processing Technology, Ministry of Education, Beijing 100084 (China); State Key Laboratory of New Ceramics and Fine Processing, Beijing 100084 (China); Shao, Yang; Zhuang, Daming [School of Materials Science and Engineering, Tsinghua University, Beijing 100084 (China); Key Laboratory for Advanced Materials Processing Technology, Ministry of Education, Beijing 100084 (China); State Key Laboratory of New Ceramics and Fine Processing, Beijing 100084 (China); Liang, Ji [Key Laboratory for Advanced Materials Processing Technology, Ministry of Education, Beijing 100084 (China); Department of Mechanical Engineering, Tsinghua University, Beijing 100084 (China)

    2014-07-01

    MoSi{sub 2}/SiC–Mo{sub 2}C gradient coating on molybdenum was in situ prepared with pack cementation process by two steps: (1) carburizing with graphite powder to obtain a Mo{sub 2}C layer on Mo substrate, and (2) siliconizing with Si powder to get a composite MoSi{sub 2}/SiC layer on the upper part of Mo{sub 2}C layer. The microstructure and elemental distribution in the coating were investigated with scanning electron microscopy (SEM), backscattered electron (BSE), energy dispersive spectroscopy (EDS), electron probe microanalysis (EPMA) and X-ray diffraction (XRD). Cyclic oxidation tests (at 500 °C, 1200 °C, 1400 °C and 1600 °C) demonstrated excellent oxidation resistance for the gradient composite coating and the mass loss was only 0.23% in 60 min at 1600 °C. XRD, EPMA, thermal dynamic and phase diagram analyses indicated that the Mo{sub 2}C barrier layer played the key role in slowing down the diffusion of C and Si toward inner Mo substrate at high temperature and principally this contributed to the excellent anti-oxidation for Mo besides the outer MoSi{sub 2}/SiC composite layer.

  18. Liquid natural gas regasification combined with adsorbed natural gas filling system.

    Science.gov (United States)

    Roszak, Eliza Anna; Chorowski, Maciej

    2012-06-01

    The article provides an introduction to innovative method of Liquid Natural Gas (LNG) physical exergy practical utilization. The energy spent to liquefy natural gas (a thermodynamic minimum is about 0.13 kWh/l of LNG depending on pressure and chemical composition) can be partly recovered in the system making use either of the LNG low temperature (111 K) or its ability to increase the pressure in a storage vessel by heat absorption from the environment. The paper presents estimation of the LNG physical exergy and its dependence on the pressure and temperature. Then description and comparison of available natural gas storage methods (liquefaction, compression, adsorption) is given, with a special attention paid to Adsorbed Natural Gas (ANG) technology. Original data concerning adsorption isotherms of methane with activated carbon MaxsorbIII are presented. A concept of ANG storage technology coupled with the LNG regasification, is a promising technique of utilization of the LNG cold exergy. The energy efficient combination of ANG with LNG may help market progress of adsorption technology in natural gas storage and distribution. The ANG/LNG coupling is especially perspective in case of small capacity and distributed natural gas deposits exploitation.

  19. Shotgun proteomic analytical approach for studying proteins adsorbed onto liposome surface.

    Science.gov (United States)

    Capriotti, Anna Laura; Caracciolo, Giulio; Cavaliere, Chiara; Crescenzi, Carlo; Pozzi, Daniela; Laganà, Aldo

    2011-09-01

    The knowledge about the interaction between plasma proteins and nanocarriers employed for in vivo delivery is fundamental to understand their biodistribution. Protein adsorption onto nanoparticle surface (protein corona) is strongly affected by vector surface characteristics. In general, the primary interaction is thought to be electrostatic, thus surface charge of carrier is supposed to play a central role in protein adsorption. Because protein corona composition can be critical in modifying the interactive surface that is recognized by cells, characterizing its formation onto lipid particles may serve as a fundamental predictive model for the in vivo efficiency of a lipidic vector. In the present work, protein coronas adsorbed onto three differently charged cationic liposome formulations were compared by a shotgun proteomic approach based on nano-liquid chromatography-high-resolution mass spectrometry. About 130 proteins were identified in each corona, with only small differences between the different cationic liposome formulations. However, this study could be useful for the future controlled design of colloidal drug carriers and possibly in the controlled creation of biocompatible surfaces of other devices that come into contact with proteins into body fluids. PMID:21725631

  20. alpha(2A)-adrenergic receptor derived peptide adsorbates: a G-protein interaction study.

    Science.gov (United States)

    Vahlberg, Cecilia; Petoral, Rodrigo M; Lindell, Carina; Broo, Klas; Uvdal, Kajsa

    2006-08-15

    The affinity of alpha(2A)-adrenergic receptor (alpha(2A)-AR) derived peptide adsorbates for the functional bovine brain G-protein is studied in the search for the minimum sequence recognition. Three short peptides (GPR-i2c, GPR-i3n, and GPR-i3c) are designed to mimic the second and third intracellular loops of the receptor. X-ray photoelectron spectroscopy is used to study the chemical composition of the peptides and the binding strength to the surfaces. Chemisorption of the peptides to the gold substrates is observed. Infrared spectroscopy is used to study the characteristic absorption bands of the peptides. The presence of peptides on the surfaces is verified by prominent amide I and amide II bands. The interaction between the peptides and the G-protein is studied with surface plasmon resonance. It is shown that GPR-i3n has the highest affinity for the G-protein. Equilibrium analysis of the binding shows that the G-protein keeps its native conformation when interacting with GPR-i3c, but during the interaction with GPR-i2c and GPR-i3n the conformation of G-protein is changed, leading to the formation of aggregates and/or multilayers. PMID:16893224

  1. Controlling SO2 by Using Low Cost Adsorbents

    Directory of Open Access Journals (Sweden)

    Nenavath Gandhi

    2013-01-01

    Full Text Available Sulphur oxides are formed during high temperature combustion processes from the oxidation of sulphur in the air. The principal source of sulphur oxides is sulphur oxide (SO and sulphur dioxide (SO2, collectively known as SOx. SO and SO2 concentrations are therefore the highest in industrial area. Other important sources are power stations, heating plants, and industrial processes. Long-term exposure to sulphur dioxide may affect lung function, and that exposure to sulphur dioxide enhances the response to allergens in sensitized individuals. The feasibility of using waste materials as adsorbent for air pollutant SOx was evaluated in the present study. The experiments were carried out in laboratory on certain waste materials like Neem leaf powder, orange peel powder, custard apple leaf powder, Horse gram seed powder, Ragi seed powder, mango bark dust, mixed algae, and Neem bark dust. The experimental investigations were carried out by traditional adsorption studies, and they showed that all substances had certain capacity to adsorb SOx from aqueous solution of SOx. The order of adsorption by different low cost materials is Mango bark dust > Orange peel powder >Custard apple leaf powder> Neem leaf powder> Horse gram seed powder> Ragi seed powder> Neem bark powder, mixed algae by 98%>95%>88%>82%>80%>78%>77%>74%, respectively. At lower concentration the adsorption is more compared to higher concentration. It is found that the adsorption increases with an increase in surface area.DOI: http://dx.doi.org/10.5755/j01.erem.62.4.1947

  2. Band mapping of surface states vs. adsorbate coverage

    Energy Technology Data Exchange (ETDEWEB)

    Rotenberg, E. [Univ. of Oregon, Eugene, OR (United States)]|[Lawrence Berkeley National Lab., CA (United States); Kevan, S.D. [Univ. of Oregon, Eugene, OR (United States); Denlinger, J.D. [Univ. of Wisconsin, Milwaukee, WI (United States); Chung, Jin-Wook [POSTECH, KyungBuk Pohang (Korea, Republic of)

    1997-04-01

    The theory of electron bands, which arises from basic quantum mechanical principles, has been the cornerstone of solid state physics for over 60 years. Simply put, an energy band is an electron state in a solid whose energy varies with its momentum (similar to, but with a more complicated dependence than, how a free electron`s energy is proportional to its momentum squared). Much attention over the last 15 years has been given to the study of band structure of surfaces and interfaces, especially as the applications of these two-dimensional systems have become increasingly important to industry and science. The ultraESCA endstation at beamline 7.01 at the Advanced Light Source was developed for very high-energy - ({approximately}50 meV) and angular - (<1{degrees}) resolution photoemission studies of materials. The high flux (typically 10{sup 12} photons/sec) makes the detailed study of the evolution of bands possible. The authors are interested in learning how, when one forms a chemical bond between a metal and an overlaying atom or molecule, the resulting charge transfer to or from the adsorbate affects the surface bands. In some cases of interest, intermediate coverages lead to different band structure than at the extremes of clean and saturated surfaces. Surfaces of tungsten are particularly interesting, as their atomic geometry has been shown to be exquisitely sensitive to both the surface vibrational and electronic properties. In this study, the authors looked at the surface bands of tungsten ((110) surface), as a function both of coverage and mass of overlaying atoms. The adsorbed atoms were hydrogen and the alkali atoms lithium and cesium.

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

    International Nuclear Information System (INIS)

    The design, construction and test run of a solid adsorption solar refrigerator are presented. It used activated carbon/methanol as the adsorbent/adsorbate pair. The refrigerator has three major components: collector/generator/adsorber, condenser and evaporator. Its flat plate type collector/generator/adsorber used clear plane glass sheet of effective exposed area of 1.2 m2. The steel condenser tube with a square plan view was immersed in pool of stagnant water contained in a reinforced sandcrete tank. The evaporator is a spirally coiled copper tube immersed in stagnant water. Adsorbent cooling during the adsorption process is both by natural convection of air over the collector plate and tubes and night sky radiation facilitated by removing the collector box end cover plates. Ambient temperatures during the adsorbate generation and adsorption process varied over 18.5-34 deg. C. The refrigerator yielded evaporator temperatures ranging over 1.0-8.5 deg. C from water initially in the temperature range 24-28 deg. C. Accordingly, the maximum daily useful cooling produced was 266.8 kJ/m2 of collector area

  4. Preparation and adsorption property of xylan/poly(acrylic acid) magnetic nanocomposite hydrogel adsorbent.

    Science.gov (United States)

    Sun, Xiao-Feng; Liu, Baichen; Jing, Zhanxin; Wang, Haihong

    2015-03-15

    Adsorbents based on natural polysaccharides have attracted increasing interest because of their low-cost and biodegradability, particularly, polysaccharide-based nanocomposite adsorbents. In this study the xylan/poly(acrylic acid) magnetic nanocomposite hydrogel adsorbent was prepared from wheat straw xylan and Fe3O4 nanoparticles, and its adsorption property was studied on methylene blue removal. The prepared hydrogel adsorbent had a semi-interpenetrating network structure and exhibited a macro-porous structure with interconnected porous channels. Super-paramagnetic characteristic behavior was observed from magnetic analysis using a vibrating sample magnetometer. The optimum condition for methylene blue adsorption on the adsorbent was found at pH 8 with an adsorbent dosage of 3g/L and an initial concentration of 400mg/L, and the removal percentage reached above 90%. The adsorption isotherm of methylene blue on the prepared hydrogel adsorbent was fitted to the Langmuir model, and the pseudo-second-order kinetic model could describe the adsorption process. All obtained results indicated that the prepared hydrogel adsorbent is promising for water treatment applications. PMID:25542101

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

    International Nuclear Information System (INIS)

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

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

    International Nuclear Information System (INIS)

    In order to use as adsorbent for removal of the soluble corrosion products, mainly Co60 under PWR reactor coolant conditions (300 deg C, 160 kg/cm2), stable ZrO2 adsorbent was prepared using sol-gel process from zirconyl nitrate, AlO adsorbent was prepared by hydrolysis of aluminum isopropoxide, and titanium tetraisopropoxide, respectively. The prepared adsorbents were calcined at various temperature and analyzed by physical properties and the Co2+ adsorption capacity. And it was shown that the Co2+ adsorption capacity of the TiO2-Al2O3 adsorbents were found to have larger than that of ZrO2 and Al2O3 adsorbents in high-temperature water. ZrO2, Al2O3 and TiO2-Al2O3 adsorbents were found to be suitable high-temperature adsorbents for the removal of dissolved corrosion products, mainly Co in PWR reactor coolant conditions. 15 tabs., 51 figs., 55 refs. (Author)

  7. Characteristic loss spectra of molybdenum deposited films and ethylene adsorbed films

    International Nuclear Information System (INIS)

    Spectra of characteristic losses of electron energy of deposited molybdenum films have been investigated. Five peaks of losses were observed. Dependence of these losses on the primary electron energy and ethylene adsorption on the surface has been investigated as well. A wide band corresponding to the excitation of different adsorbate orbitals is appeared in film spectra with adsorbed sthylene

  8. Uptake of uranium from seawater by amidoxime-based polymeric adsorbent marine testing

    International Nuclear Information System (INIS)

    Amidoxime-based polymer adsorbents in the form of functionalized fibers were prepared at the Oak Ridge National Laboratory (ORNL) and screened in laboratory experiments, in terms of uranium uptake capacity, using spiked uranium solution and seawater samples. Batch laboratory experiments conducted with 5-gallon seawater tanks provided equilibrium information. Based on results from 5-gallon experiments, the best adsorbent was selected for field-testing of uranium adsorption from seawater. Flow-through column tests have been performed at different marine sites to investigate the uranium uptake rate and equilibrium capacity under diverse biogeochemistry. The maximum amount of uranium uptake from seawater tests at Sequim, WA, was 3.3 mg U/g adsorbent after eight weeks of contact of the adsorbent with seawater. This amount was three times higher than the maximum adsorption capacity achieved in this study by a leading adsorbent developed by the Japan Atomic Energy Agency (JAEA), which was 1.1 mg U/g adsorbent at equilibrium. The initial uranium uptake rate of the ORNL adsorbent was 2.6 times higher than that of the JAEA adsorbent under similar conditions. A mathematical model derived from the mass balance of uranium was employed to describe the data. (authors)

  9. A new, low-cost adsorbent: preparation, characterization, and adsorption behavior of Pb(II) and Cu(II).

    Science.gov (United States)

    Huang, Gailing; Wang, Dong; Ma, Shulan; Chen, Junli; Jiang, Ling; Wang, Peiyuan

    2015-05-01

    This work aimed to develop waste (i.e., sulfonated lignin) application in simulated wastewater treatment. Sulfonated lignin (LS), a byproduct of the paper industry, was intercalated into a parent host of layered double hydroxides (LDH) by swelling-restacking method. X-ray diffraction patterns of the composite confirmed that long-chain LS anions exited in the interlayer of Mg2Al-LDH in two forms: (1) a "flat" form with d003=0.88 nm; and (2) a "vertical" form with d003=9.08 nm. Results showed that the obtained Mg2Al-LS-LDH composite was highly selective and efficient for the removal of Pb(2+) and Cu(2+), especially Pb(2+), compared with the NO3-LDH precursor. The coexisting cations decreased the removal efficiency of Pb(2+) or Cu(2+) on Mg2Al-LS-LDH composite, which could be ascribed to outer-sphere sorption style, and the effect order of cations is Li(+)>Ca(2+)>K(+)>Na(+). The pseudo-second-order model appropriately described the sorption kinetics of Mg2Al-LS-LDH composite for Pb(2+) and Cu(2+). Sorption isotherms for Pb(2+) and Cu(2+) by the Mg2Al-LS-LDH composite were found to be more satisfactorily fitted by the Langmuir model than by the Freundlich one. With increased Pb(2+) or Cu(2+) concentration from 2 ppm to 200 ppm, the maximum absorption capacity of the composite toward Pb(2+) was ?123 mg/g and that toward Cu(2+) was ?64 mg/g. Therefore, a new, low-cost adsorbent was synthesized by utilizing the byproduct LS, which may be a potential remedy for Pb(2+) or Cu(2+) in contaminated water. PMID:25626135

  10. Elimination of dyes from aqueous solutions using iron oxides and chitosan as adsorbents: a comparative study

    Scientific Electronic Library Online (English)

    Silvina, Pirillo; Viviana, Pedroni; Elsa, Rueda; María, Luján Ferreira.

    Full Text Available This work investigates the adsorption of Alizarin, Eriochrome Blue Black R and Fluorescein using chitosan, goethite and magnetite as adsorbents. For Alizarin, the best adsorbent is chitosan with a Langmuir parameter of 15.8 mmol dye/g adsorbent. For Eriochrome Blue Black R only 1.94 mmol dye/g chito [...] san is adsorbed. Langmuir parameters for the Alizarin adsorption on both iron oxides display one or two orders of magnitude lower than for chitosan and two orders of magnitude lower in the case of Eriochrome Blue Black R. Fluorescein does not adsorb in appreciable amounts on chitosan and it presents the lower affinity on the iron oxides.

  11. Solid-state conversion of fly ash to effective adsorbents for Cu removal from wastewater.

    Science.gov (United States)

    Wang, Shaobin; Li, Lin; Zhu, Z H

    2007-01-10

    Solid-state conversion of fly ash to an amorphous aluminosilicate adsorbent (geopolymer) has been investigated under different conditions and the synthesised material has been tested for Cu2+ removal from aqueous solution. It has been found that higher reaction temperature and Na:FA ratio will make the adsorbents achieving higher removal efficiency. The adsorbent loading and Cu2+ initial concentration will also affect the removal efficiency while the adsorption capacity exhibits similarly at 30-40 degrees C. The adsorption capacity of the synthesised adsorbent shows much higher value than fly ash and natural zeolite. The capacity is 0.1, 3.5 and 92 mg/g, for fly ash, natural zeolite, and FA derived adsorbent, respectively. The kinetic studies indicate that the adsorption can be fitted by the second-order kinetic model. Langmuir and Freundlich isotherms also can fit to the adsorption isotherm. PMID:16839666

  12. Chirality transfer from gold nanocluster to adsorbate evidenced by vibrational circular dichroism

    Science.gov (United States)

    Dolamic, Igor; Varnholt, Birte; Bürgi, Thomas

    2015-01-01

    The transfer of chirality from one set of molecules to another is fundamental for applications in chiral technology and has likely played a crucial role for establishing homochirality on earth. Here we show that an intrinsically chiral gold cluster can transfer its handedness to an achiral molecule adsorbed on its surface. Solutions of chiral Au38(2-PET)24 (2-PET=2-phenylethylthiolate) cluster enantiomers show strong vibrational circular dichroism (VCD) signals in vibrations of the achiral adsorbate. Density functional theory (DFT) calculations reveal that 2-PET molecules adopt a chiral conformation. Chirality transfer from the cluster to the achiral adsorbate is responsible for the preference of one of the two mirror images. Intermolecular interactions between the adsorbed molecules on the crowded cluster surface seem to play a dominant role for the phenomena. Such chirality transfer from metals to adsorbates likely plays an important role in heterogeneous enantioselective catalysis. PMID:25960309

  13. Sequestering Nickel (II Ions from Aqueous Solutions Using Various Adsorbents: A Review

    Directory of Open Access Journals (Sweden)

    Olugbenga Solomon Bello

    2014-06-01

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

  14. Thermodynamic formalism of water uptakes on solid porous adsorbents for adsorption cooling applications

    International Nuclear Information System (INIS)

    This Letter presents a thermodynamic formulation to calculate the amount of water vapor uptakes on various adsorbents such as zeolites, metal organic frameworks, and silica gel for the development of an advanced adsorption chiller. This formalism is developed from the rigor of the partition distribution function of each water vapor adsorptive site on adsorbents and the condensation approximation of adsorptive water molecules and is validated with experimental data. An interesting and useful finding has been established that the proposed model is thermodynamically connected with the pore structures of adsorbent materials, and the water vapor uptake highly depends on the isosteric heat of adsorption at zero surface coverage and the adsorptive sites of the adsorbent materials. Employing the proposed model, the thermodynamic trends of water vapor uptakes on various adsorbents can be estimated

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

    International Nuclear Information System (INIS)

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

  16. Atmospheric fate of oil matter adsorbed on sea salt particles under UV light

    Science.gov (United States)

    Vaitilingom, M.; Avij, P.; Huang, H.; Valsaraj, K. T.

    2014-12-01

    The presence of liquid petroleum hydrocarbons at the sea water surface is an important source of marine pollution. An oil spill in sea-water will most likely occur due to an involuntary accident from tankers, offshore platforms, etc. However, a large amount of oil is also deliberately spilled in sea-water during the clean-out process of tank vessels (e.g. for the Mediterranean Sea, 490,000 tons/yr). Moreover, the pollution caused by an oil spill does not only affect the aquatic environment but also is of concern for the atmospheric environment. A portion of the oil matter present at the sea-water surface is transported into the atmosphere viaevaporation and adsorption at the surface of sea spray particles. Few studies are related to the presence of oil matter in airborne particles resulting from their adsorption on sea salt aerosols. We observed that the non-volatile oil matter was adsorbed at the surface of sea-salt crystals (av. size of 1.1 ?m). Due to their small size, these particles can have a significant residence time in the atmosphere. The hydrocarbon matter adsorbed at the surface of these particles can also be transformed by catalyzers present in the atmosphere (i.e. UV, OH, O3, ...). In this work, we focused on the photo-oxidation rates of the C16 to C30alkanes present in these particles. We utilized a bubble column reactor, which produced an abundance of small sized bubbles. These bubbles generated droplets upon bursting at the air-salt water interface. These droplets were then further dried up and lifted to the top of the column where they were collected as particles. These particles were incubated in a controlled reactor in either dark conditions or under UV-visible light. The difference of alkane content analyzed by GC-MS between the particles exposed to UV or the particles not exposed to UV indicated that up to 20% in mass was lost after 20 min of light exposure. The degradation kinetics varied for each range of alkanes (C16-20, C21-25, C26-30) from 20 to 60 ?g L-1 min-1. To observe the effect on air composition when samples are exposed to solar light, experiments were conducted under controlled atmospheric conditions: oxygen free or with O3 gas. The results showed the importance of the photo-transformation processes of oil in airborne particles and its relation to the gaseous nature of the ambient atmosphere.

  17. Adsorbate-induced anchoring transitions of liquid crystals on surfaces presenting metal salts with mixed anions.

    Science.gov (United States)

    Hunter, Jacob T; Abbott, Nicholas L

    2014-02-26

    We report that metal salts composed of mixtures of anions of differing coordination strength can be used to increase the sensitivity and selectivity of adsorbate-induced anchoring transitions of liquid crystals (LCs) supported on surfaces decorated with the metal salts. Specifically, the dynamics of anchoring transitions triggered by the adsorbate dimethyl methylphosphonate (DMMP) on surfaces of aluminum(III) salts were analyzed within the framework of a model for mass transport to reveal that the sensitivity of a nitrile-containing nematic LC to DMMP increased from 250 to 25 ppb when the composition of the (counter) anion was changed from 100% perchlorate to 90% nitrate and 10% perchlorate (by mole percent). To provide insight into these observations, polarization-modulation infrared reflectance-absorbance spectroscopy (PM-IRRAS) was used to show that the intensity of the absorption band in the IR spectrum corresponding to the coordinated state of the nitrile group (but not the position of the peak) decreased with the increase in the mole fraction of the strongly coordinating anion (nitrate) in the anion mixture, thus suggesting that the addition of the strongly coordinating anion decreased the number of coordination interactions (per unit area of the interface) but not the strength of the individual coordination interactions between the metal cation and the LC. We also measured the incorporation of the nitrate anion into the metal salt to decrease the effect of humidity on the dynamic response of the LC to DMMP, a result that is consistent with weaker interactions between the nitrate anion and water as compared to the perchlorate anion and water. Finally, the bidentate anion acetylacetonate was measured to cause a similar increase in sensitivity to DMMP when mixed with perchlorate in a 1:1 ratio (the resulting sensitivity of the system to DMMP was 100 ppb). Overall, these results suggest that tailoring the identity of the anion represents a general and facile approach for tuning the orientational response of LCs supported on metal salts to targeted analytes. PMID:24369715

  18. Carbon-fiber composite molecular sieves for gas separation

    Energy Technology Data Exchange (ETDEWEB)

    Jagtoyen, M.; Derbyshire, F.; Kimber, G.; Fei, Y.Q. [Univ. of Kentucky Center for Applied Energy Research, Lexington, KY (United States)

    1995-08-01

    The progress of research in the development of novel, rigid, monolithic adsorbent carbon fiber composites is described. Carbon fiber composites are produced at ORNL and activated at the CAER using steam or CO{sub 2} under different conditions, with the aims of producing a uniform degree of activation through the material, and of closely controlling pore structure and adsorptive properties The principal focus of the work to date has been to produce materials with narrow porosity for use in gas separations.

  19. ADSORPTION OF COLOR FROM A STOCK SOLUTION USING NEEM LEAVES POWDER AS A LOW-COST ADSORBENT

    OpenAIRE

    Ghanshyam G. Pandhare; Nikhilesh Trivedi; S. D. Dawande

    2013-01-01

    The regular commercial activated carbon is expensive, so there is a need of alternatives for such application. In present study Neem leaves powder activated using chemical treatment as a low-cost adsorbent. And experiment has done with different weight of adsorbent. The potential of Neem leaves powder adsorbent to remove color impurities from industrial effluent is good. Adsorption isotherm of color solution on adsorbent were determine and correlation with common isotherm equations such as Fr...

  20. The effect of the presence of Ag nanoparticles on the photocatalytic degradation of oxalic acid adsorbed on TiO2 nanoparticles monitored by ATR-FTIR

    International Nuclear Information System (INIS)

    Photocatalytic degradation of oxalic acid adsorbed on the Ag/P25 TiO2 composite nanoparticle films were investigated using ATR-FTIR technique under UV irradiation. Ag/P25 TiO2 composite nanoparticle films with various Ag content were tested. Topography and chemical structure/composition of the composite nanoparticle films were analyzed by AFM and XPS respectively. It was found that in the degradation reaction of the oxalic acid, the presence of only 2% Ag nanoparticles leads to six times more oxalic acid degradation compared to that degraded in the presence of pure P25 TiO2 nanoparticles. The degradation rate of the oxalic acid is three times higher in the case of Ag/TiO2 composite nanoparticle film than in the case of pure TiO2 nanoparticles. It was observed that both the rate of oxalic acid degradation and the degraded amount of the oxalic acid were significantly affected by Ag incorporation. - Highlights: • Uniform Ag/TiO2 composite nanoparticle films with various Ag content was prepared. • Photocatalytic degradation of oxalic acid flowing through the films was examined. • Degraded amount and degradation rate of the oxalic acid increase with Ag content. • Ag/TiO2 composite nanoparticle films show superior photocatalytic activity