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

    Science.gov (United States)

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

  3. Remediation of fluoride from drinking water using magnetic iron oxide coated hydrotalcite/chitosan composite.

    Science.gov (United States)

    Pandi, Kalimuthu; Periyasamy, Soodamani; Viswanathan, Natrayasamy

    2017-02-16

    The present study was performed to examine the probability of magnetic iron oxide fabricated hydrotalcite/chitosan (Fe3O4@HTCS) composite for the removal of excess fluoride content from drinking water. The developed Fe3O4@HTCS composite not only demonstrate the good separation ability but also display an extreme enhanced defluoridation capacity (DC) when compared to other base components and composite. The DCs of Fe3O4@HTCS composite, Fe3O4@HT composite, Fe3O4, HT and CS was found to be 5032, 3041, 1050, 1030 and 52mgF(-)/kg respectively. The structure and morphology of the prepared adsorbent and fluoride sorbed adsorbent was analysed using FTIR, SEM and EDAX with mapping techniques. The dependence of DC on various parameters like initial fluoride concentration, pH, contact time, interfering anions and temperature was studied by batch method. From isotherm modeling, the equilibrium data is well described by Freundlich, Langmuir and Dubinin-Radushkevich (D-R) isotherms. Thermodynamic parameters confirm the spontaneity and endothermic nature of the fluoride adsorption. The performance of Fe3O4@HTCS composite to field water sample designates its adaptable nature at field conditions.

  4. FORMATION AND RESEARCH OF MULTI-LAYER COMPOSITE PLASMA OXIDE COATINGS BASED ON ELEMENTS OF SCREEN METEROID PTOTECTION

    Directory of Open Access Journals (Sweden)

    V. A. Okovity

    2016-01-01

    Full Text Available The paper presents results of research for influence of plasma jet parameters (current, spraying distance, plasmasupporting nitrogen gas consumption, fractional composition of an initial powder and cooling degree by compressed air on characteristics of anti-meteorite coatings, subsequent processing modes by pulsed plasma. Properties of the obtained coatings and results of ballistic tests have been given in the paper. The proposed methodology has been based on complex metallographic, X-ray diffraction and electron microscopic investigations of anti-meteorite aluminum oxide coating. Optimization of air plasma spraying parameters for NiAl and Al2O3 materials has been carried out in the paper. The spraying parameters optimization has been executed on the basis of obtaining maximum materials utilization factor. Surface treatment of model screen elements with a double-layer composite coating (adhesive metal NiAl layer and hard ceramic oxide Al2O3 layer has been fulfilled while using compression plasma stream. Nitrogen has been used as working gas. Composite hard ceramic oxide Al2O3 coating is represented by porous structure consisting of 10–15 µm-size fused Al2O3 particles. Metallic inclusions formed due to erosion of plasmatron electrodes have been observed in the space between the particles. Surface of bilayer composite coatings has been processed by a compression plasma stream and due to nonsteady processes of melting and recrystallization high strength polycrystalline layer has been formed on their surface. In this context, those areas of the polycrystalline layer which had metal inclusions have appeared to be painted in various colors depending on chemical composition of the inclusions.

  5. A note on chemical composition and origin of ferromanganese oxide coated and uncoated pumice samples from central Indian Ocean basin

    Digital Repository Service at National Institute of Oceanography (India)

    Pattan, J.N.; Parthiban, G.; Moraes, C.; Rajalakshmi, R.; Lekshmi, S.; Athira, S.; JaiSankar, S.

    Pumice are explosive volcanic product, occur as uncoated or coated with ferromanganese (Fe-Mn) oxide and resides in association with ferromanganese nodules on the seabed in Central Indian Ocean Basin (CIOB). The older Fe-Mn oxide coated and younger...

  6. 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 μg/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 % .

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

    Energy Technology Data Exchange (ETDEWEB)

    Li, Zhijun [Key Laboratory of Superlight Materials and Surface Technology, College of Materials Science and Chemical Engineering, Harbin Engineering University, Harbin 150001 (China); Yuan, Yi, E-mail: yi.yuan@hrbeu.edu.cn [Key Laboratory of Superlight Materials and Surface Technology, College of Materials Science and Chemical Engineering, Harbin Engineering University, Harbin 150001 (China); Jing, Xiaoyan [Key Laboratory of Superlight Materials and Surface Technology, College of Materials Science and Chemical Engineering, Harbin Engineering University, Harbin 150001 (China)

    2012-11-15

    Highlights: Black-Right-Pointing-Pointer The PEO coatings exhibit tunable characteristics by controlling the current density. Black-Right-Pointing-Pointer The coating formed at 5 A/dm{sup 2} exhibits the highest corrosion resistance. Black-Right-Pointing-Pointer 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 {gamma}-Mg{sub 2}SiO{sub 4} and {alpha}-Mg{sub 2}SiO{sub 4} 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/dm{sup 2} is attributed to the compactness of the barrier layer and the highest MgO/Mg{sub 2}SiO{sub 4} ratio.

  8. Microstructure of a Mo-Si-C-N multi-layered anti-oxidation coating on carbon/carbon composites by fused slurry

    Institute of Scientific and Technical Information of China (English)

    LAI Zhonghong; MENG Songhe; ZHU Jingchuan; JEON Jaeho

    2009-01-01

    A Mo-Si-C-N multi-layered anti-oxidation coating was in-situ fabricated by introducing nitrogen atmosphere during the fused sintering of Mo-Si slurry pre-layer on carbon/carbon composites. The phase composition and microstructure of the Mo-Si-C-N coating were character-ized by X-ray diffractometry, optical microscopy, scanning electron microscopy with energy dispersive spectroscopy, X-ray photoelectron spectroscopy, and transmission electron microscopy. The Mo-Si-C-N coating exhibited a three-layered structure. Besides the MoSi2/Si main-layer and the SiC bonding-layer, a surface layer of about 10 μm in thickness was synthesized on the coating surface. The surface layer mainly consisted of SiC nanowires and contained some Si3N4 and Si phases. SiC nanowires of 10 to 200 nm in diameter presented a terrace and distortion structure. Transmission electron microscopy indicated that the SiC nanowires grew along the preferred direction. Dur-ing oxidation test, SiC nanowires transmuted into Sit2 glass, which can play an important role in improving the oxidation resistance of C/C composites.

  9. 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 (E(g)) 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.

  10. 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

    2015-03-12

    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%.

  11. 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

  12. 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.

  13. Characterization and adsorption behavior of a novel triolein-embedded activated carbon composite adsorbent

    Institute of Scientific and Technical Information of China (English)

    RU Jia; LIU Huijuan; QU Jiuhui; WANG Aimin; DAI Ruihua

    2005-01-01

    A novel triolein-embedded activated carbon composite adsorbent was developed. Experiments were carried out in areas such as the preparation method, the characterization of physicochemical properties, and the adsorption behavior of the composite adsorbent in removing dieldrin from aqueous solution. Results suggested that the novel composite adsorbent was composed of the supporting activated carbon and the surrounding triolein-embedded cellulose acetate membrane. The adsorbent was stable in water, for no triolein leakage was detected after soaking the adsorbent for five weeks. The adsorbent had good adsorption capability to dieldrin, which was indicated by a residual dieldrin concentration of 0.204 μg·L-1. The removal efficiency of the composite adsorbent was higher than the traditional activated carbon adsorbent.

  14. Fabrication and thermal conductivity improvement of novel composite adsorbents adding with nanoparticles

    Science.gov (United States)

    Wu, Qibai; Yu, Xiaofen; Zhang, Haiyan; Chen, Yiming; Liu, Liying; Xie, Xialin; Tang, Ke; Lu, Yiji; Wang, Yaodong; Roskilly, Anthony Paul

    2016-10-01

    Thermal conductivity is one of key parameters of adsorbents, which will affect the overall system performance of adsorption chiller. To improve adsorbent's thermal conductivity is always one of research focuses in chemisorption field. A new chemical composite adsorbent is fabricated by adding carbon coated metal(Aluminum and Nickel) nanoparticles with three different addition amounts into the mixture of chloride salts and natural expanded graphite aiming to improve the thermal conductivity. The preparation processes and its thermal conductivity of this novel composite adsorbent are reported and summarized. Experimental results indicate that the nanoparticles are homogenously dispersed in the composite adsorbent by applying the reported preparation processes. The thermal conductivity of the composite adsorbent can averagely enlarge by 20% when the weight ratio of the added nanoparticles is 10 wt%. Moreover, carbon coated aluminum nanoparticles exhibit more effective enlargement in thermal conductivity than nickel nanoparticles. As for the composite adsorbent of CaCl2-NEG, there is a big reinforcement from 30% to 50% for Al@C nanoparticles, however only 10% in maximum caused by Ni@C nanoparticles. The proposed research provides a methodology to design and prepare thermal conductive chemical composite adsorbent.

  15. Removing Cd2+ by Composite Adsorbent Nano-Fe3O4/Bacterial Cellulose

    Institute of Scientific and Technical Information of China (English)

    LU Min; GUAN Xiao-hui; WEI De-zhou

    2011-01-01

    A new composite adsorbent,nano-Fe3O4/bacterial cellulose(BC),was prepared through blending method.The process of adsorbing Cd2+ including its isotherm and kinetics measured was studied.The results show that the adsorption efficiency is improved because of huge surface area and surface coordination of nano-Fe3O4 particles.Its adsorption capacity is 27.97 mg/g and the maximum of Cd2+ removal is 74%.The adsorption kinetics can be described by pseudo-second rate model and the adsorption equilibrium by Langmuir type.The superparamagnetism of nano-Fe3O4 particles can help to solve the difficult separation of single BC adsorbent and lead to the quick separation of composite adsorbent from the liquid if a magnetic field was applied.Cd2+ can be desorbed effectively by EDTA and HCl from the composite adsorbent,which can make it be reused.

  16. The Relationship of Culture Media Composition and Chemical Composition on Spirulina sp for Metal Ion Adsorbent

    Directory of Open Access Journals (Sweden)

    Hilda Zulkifli

    2016-12-01

    Full Text Available The analysis relationship of Spirulina sp medium with chemical composition has been conducted. Chemical analysis was performed using X-Ray Fluorescence analysis. Furthermore, potention of Spirulina sp as adsorbent of metal ions was analyzed using FTIR spectroscopy. The results showed that metals such as Zn, Fe, Mn, Ca, Cu, and Mo were mainly metals in Spirulina sp. These metals were not correlated with cultivated medium of Spirulina sp. Analysis of potention Spirulina sp as metal ions adsorbent showed that Spirulina sp has functional groups –C=O and –OH as ligand. Intercation of metal ions Cu(II and Cr(III with Spirulina sp indicated that metal ions bond to –C=O functional group.

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

    Science.gov (United States)

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

    2014-02-01

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

  18. Copper ions removal from water using functionalized carbon nanotubes–mullite composite as adsorbent

    Energy Technology Data Exchange (ETDEWEB)

    Tofighy, Maryam Ahmadzadeh; Mohammadi, Toraj, E-mail: torajmohammadi@iust.ac.ir

    2015-08-15

    Highlights: • CNTs–mullite composite was prepared via chemical vapor deposition (CVD) method. • The prepared composite was modified with concentrated nitric acid and chitosan. • The modified CNTs–mullite composites were used as novel adsorbents. • Copper ion removal from water by the prepared adsorbents was performed. • Langmuir and Freundlich isotherms and two kinetic models were applied to fit the experimental data. - Abstract: Carbon nanotubes–mullite composite was synthesized by direct growth of carbon nanotubes on mullite particles via chemical vapor deposition method using cyclohexanol and ferrocene as carbon precursor and catalyst, respectively. The carbon nanotubes–mullite composite was oxidized with concentrated nitric acid and functionalized with chitosan and then used as a novel adsorbent for copper ions removal from water. The results demonstrated that modification with concentrated nitric acid and chitosan improves copper ions adsorption capacity of the prepared composite, significantly. Langmuir and Freundlich isotherms and two kinetic models were applied to fit the experimental data. The carbon nanotubes growth on mullite particles to form the carbon nanotubes–mullite composite with further modification is an inherently safe approach for many promising environmental applications to avoid some concerns regarding environment, health and safety. It was found that the modified carbon nanotubes–mullite composite can be considered as an excellent adsorbent for copper ions removal from water.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    1996-12-01

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

  20. Studies on broad spectrum corrosion resistant oxide coatings

    Indian Academy of Sciences (India)

    Someswar Datta

    2001-12-01

    The corrosion resistant oxide coatings, developed and applied by the conventional vitreous enamelling techniques, showed superior resistance to a range of mineral acids at various strengths and temperatures, alkaline solutions, boiling water and chrome plating solutions. These coatings possess considerable abrasion and impact resistance as well as high thermal shock resistance. The properties of the coating system have been studied in detail and found to be strongly dependent on composition and processing parameters. These coatings have been characterized by X-ray diffraction analysis and SEM studies. Some of the coating materials have been found to be biocompatible.

  1. Phosphorylated cellulose triacetate-silica composite adsorbent for recovery of heavy metal ion.

    Science.gov (United States)

    Srivastava, Niharika; Thakur, Amit K; Shahi, Vinod K

    2016-01-20

    Phosphorylated cellulose triacetate (CTA)/silica composite adsorbent was prepared by acid catalyzed sol-gel method using an inorganic precursor (3-aminopropyl triethoxysilane (APTEOS)). Reported composite adsorbent showed comparatively high adsorption capacity for Ni(II) in compare with different heavy metal ions (Cu(2+), Ni(2+), Cd(2+) and Pb(2+)). For Ni(II) adsorption, effect of time, temperature, pH, adsorbent dose and adsorbate concentration were investigated; different kinetic models were also evaluated. Thermodynamic parameters such as ΔG°, ΔH° and ΔS° were also estimated and equilibrium adsorption obeyed Langmuir and Freundlich isotherms. Developed adsorbent exhibited about 78.8% Ni(II) adsorption at pH: 6 and a suitable candidate for the removal of Ni(II) ions from wastewater. Further, about 65.5% recovery of adsorbed Ni(II) using EDTA solution was demonstrated, which suggested effective recycling of the functionalized beads would enable it to be used in the treatment of contaminated water in industry.

  2. The base metal of the oxide-coated cathode

    Energy Technology Data Exchange (ETDEWEB)

    Poret, F. [Thomson, S.B.U. Displays, Electron Optics Laboratory, Avenue du General de Gaulle, 21110 Genlis (France)]. E-mail: fabian.poret@thomson.net; Roquais, J.M. [Thomson, S.B.U. Displays, Electron Optics Laboratory, Avenue du General de Gaulle, 21110 Genlis (France)

    2005-09-15

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

  3. 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.

  4. High-capacity composite adsorbents for nucleic acids.

    Science.gov (United States)

    Tiainen, Peter; Rokebul Anower, M; Larsson, Per-Olof

    2011-08-05

    Cytopore™ is a bead-shaped, macroporous and easily compressible cellulose-based anion-exchange material intended for cultivation of anchor-dependent animal cells. Reticulated vitreous carbon (RVC) is a strong, non-compressible, high voidage (97%) matrix material that can be cut to desired geometrical shapes. Cytopore and RVC were combined to cylindrical composites (25 mm × 10 mm) fitted inside chromatography columns. The composite combined the advantageous properties of both its constituents, making it suitable for column chromatography. The composite could withstand very high flow rates without compaction of the bed (>25 column volumes/min; 4000 cm h(-1)). Chromatography runs with tracers showed a low HETP value (0.3mm), suggesting that pore flow was in operation. The dynamic binding capacities (10% breakthrough) per gram of dry weight Cytopore were determined for several compounds including DNA and RNA and were found to be 240-370 mg/g. The composite was used to isolate pUC 18-type plasmids from a cleared alkaline lysate in a good yield. Confocal microscopy studies showed that plasmids were bound not only to the surface of the Cytopore material but also within the matrix walls, thus offering an explanation to the very high binding capacities observed. The concept of using a composite prepared from a mechanically weak, high-binding material and a strong scaffold material may be applied to other systems as well.

  5. Ionic liquids modified graphene oxide composites: a high efficient adsorbent for phthalates from aqueous solution

    Science.gov (United States)

    Zhou, Xinguang; Zhang, Yinglu; Huang, Zuteng; Lu, Dingkun; Zhu, Anwei; Shi, Guoyue

    2016-12-01

    In 2015, more than 30% of erasers were found to contain a PAE content that exceeded the 0.1% limit established by the Quality and Technology Supervision Bureau of Jiangsu Province in China. Thus, strengthening the supervision and regulation of the PAE content in foods and supplies, in particular, remains necessary. Graphene oxide (GO) and its composites have drawn great interests as promising adsorbents for polar and nonpolar compounds. However, GO-based adsorbents are typically restricted by the difficult separation after treatment because of the high pressure in filtration and low density in centrifugation. Herein, a series of novel ionic liquids modified graphene oxide composites (GO-ILs) were prepared as adsorbents for phthalates (PAEs) in eraser samples, which overcame the conventional drawbacks. These novel composites have a combination of the high surface area of graphene oxide and the tunability of the ionic liquids. It is expected that the GO-ILs composites can be used as efficient adsorbents for PAEs from aqueous solution. This work also demonstrated a new technique for GO-based materials applied in sample preparation.

  6. Characterization of microarc oxidation coatings on pure titanium

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    The morphology, composition, and phase structure of the oxide coatings produced on the surface of pure titaniumby alternating-current microarc discharge in aluminate solution were investigated by X-ray diffraction and scanning electronmicroscopy. The profiles of the hardness H and the elastic modulus E in the coatings were determined using a nanoindenta-tion method. The concentration distributions of Ti, Al, and O in the coating show that this coating over 30 μm thick containstwo layers: an outer layer and an inner layer. The oxide coating is mainly composed of TiO2 rutile and Al2TiO5 compounds.During oxidation, the temperature in the microarc discharge channel was very high to make the local coating molten. Fromthe surface to the interior of the coating, H and E increase gradually, and then reach maximum values of 9.78 GPa and 176GPa respectively at a distance of 7 μm from the coating/titanium interface. They are also rather high near the interface.

  7. The comparison of Cu(Ⅱ) adsorption capability of baker's yeast, nano-titania and their composite adsorbent

    Institute of Scientific and Technical Information of China (English)

    ZHANG YunSong; WANG RenGuo; WANG XianXiang; LEI SanZhong; TONG DongMei

    2008-01-01

    The anatase nano-TiO2 powder, with crystal size between 40 and 80 nm, was prepared by the liquid phase hydrolysis of TiOCI4. At the same time, the nano-TiO2was utilized with the baker's yeast biomass as a composite adsorbent to adsorb the Cu ions in the artificial aqueous solution. The investigation showed that the composite adsorbent had a fine adsorption efficiency. The TiO2 in the composite ad-sorbent could cooperate well with baker's yeast to improve the adsorbing capability of Cu2+ under the following experimental conditions as well: a quantity of composite adsorbent of 5 g·L-1, pH≥4.0, an adsorption time of 40 rain and an initial concentration of Cu ions of 10 mg·L-1. In addition, the results of measurements, obtained with a scanning electron microscope, an infrared spectrophotometer and a Zeta potential analyzer, revealed that the baker's yeast and nano-TiO2 produced the composite ad-sorbent through coordination and hydrogen bonds in particular, etc. The stability of the composite adsorbent and the amount of titania loaded were largely dependent on the concentration of hydrogen ion in the solution.

  8. Decolorization of black liquor from bioethanol G2 production using iron oxide coating sands

    Science.gov (United States)

    Barlianti, Vera; Triwahyuni, Eka; Waluyo, Joko; Sari, Ajeng Arum

    2017-01-01

    Bioethanol G2 production using oil palm empty fruit bunch as raw material consists of four steps, namely pretreatment, hydrolysis, fermentation, and purification process. Pretreatment process generates black liquor that causes serious environmental pollution if it is released to the environment. The objective of this research is studying the ability of iron oxide coating sands to adsorb the color of black liquor. The iron oxide coating sands were synthesized from FeCl3.6H2O with quartz sands as support material. This research was conducted on batch mode using black liquor in various pH values. Result obtained that kind of iron oxide on quartz sands's surface was goethite. The result also indicated decreasing of color intensity of black liquor after adsorption process. This research supports local material utilization in environmental technology development to solve some environmental problems.

  9. 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

  10. Novel Nanosized Adsorbing Composite Cathode Materials for the Next Generational Lithium Battery

    Institute of Scientific and Technical Information of China (English)

    ZHANG Yong; ZHENG Wei; ZHANG Ping; WANG Lizhen; XIA Tongchi; HU Xinguo; YU Zhenxing

    2007-01-01

    A novel carbon-sulfur nano-composite material was synthesized by heating sublimed sulfur and high surface area activated carbon (HSAAC) under certain conditions. The physical and chemical performances of the novel carbon-sulfur nano-composite were characterized by scanning electron microscopy (SEM), Brunauer-Emmett-Teller (BET) and X-ray diffraction (XRD). The electrochemical performances of nano-composite were characterized by charge-discharge characteristic, cyclic voltammetry and electrochemical impendence spectroscopy (EIS). The experimental results indicate that the electrochemical capability of nanocomposite material was superior to that of traditional S-containing composite material. The cathode made by carbon-sulfur nano-composite material shows a good cycle ability and a high specific charge-discharge capacity. The HSAAC shows a vital role in adsorbing sublimed sulfur and the polysulfides within the cathode and is an excellent electric conductor for a sulfur cathode and prevents the shuttle behavior of the lithium-sulfur battery.

  11. Synthesis of bio-active titanium oxide coatings stimulated by electron-beam plasma

    Directory of Open Access Journals (Sweden)

    Vasilieva Tatiana

    2014-11-01

    Full Text Available Advantages of the electron-beam plasma (EBP for production of bioactive titanium oxide coatings were experimentally studied. The coatings were synthesized in EBP of oxygen on the surface of plane titanium substrates. A number of analytical techniques were used to characterize morphology, chemical composition, and structure of the synthesized titanium oxide. The analysis showed the titanium oxide (IV in the rutile form to predominate in the coatings composition.

  12. (3) Development of composite adsorbents for high decontamination and their selective adsorption properties

    Science.gov (United States)

    Mimura, Hitoshi; Yamagishi, Isao

    In an action for the convergence of the Fukushima Daiichi Nuclear Power Plant accident, the completion of Step 2 was declared in last December, 2011. As for the circulating cooling system supporting the cold shutdown of nuclear reactor, the temporary treatment equipment operation maintains stability. On the other hand, the establishment of permanent equipments, safety storage, treatment and disposal for the secondary solid wastes are urgent subjects. This special issue deals with the development of highly functional composite adsorbents and the evaluation of selective adsorption properties. The technical issues for the stable treatment and disposal of solid wastes are further discussed.

  13. Electrochemical regeneration of a reduced graphene oxide/magnetite composite adsorbent loaded with methylene blue.

    Science.gov (United States)

    Sharif, Farbod; Gagnon, Luke R; Mulmi, Suresh; Roberts, Edward P L

    2017-05-01

    In this work, two different reduced graphene oxide/iron oxide (rGO-IO) nanocomposites with different iron oxide loadings were fabricated using a one-step solvothermal method. The structure, properties and applications of the synthesized nanocomposites were evaluated with Raman spectroscopy, attenuated total reflectance Fourier transform infrared spectroscopy, thermogravimetric analysis, X-ray diffraction, electron microscopy, and energy-dispersive X-ray spectroscopy. The iron oxide is in the form of magnetite (Fe3O4), so that the resultant adsorbent can readily be separated from the treated water using a magnetic field. The ability of the nanocomposites to remove methylene blue (MB) from water by adsorption was investigated. The highest adsorptive capacity observed was 39 mg g(-1), for the composite containing 60 wt% iron oxide. The adsorptive capacity of the rGO-IO decreased to 26 mg g(-1) when the mass fraction of iron oxide was increased to 75 wt%. Electrochemical regeneration of MB loaded rGO-IO was also investigated. The electrochemical regeneration was found to be rapid and with low electrical energy consumption relative to conventional adsorbents, due to the high electrical conductivity and nonporous surface of the rGO. A regeneration efficiency of 100% was obtained after 30 min of electrochemical treatment using a 2 mm thick bed of rGO-IO loaded with 39 mg g(-1) MB, using a current density of 10 mA cm(-2). Multiple adsorption-electrochemical regeneration cycles demonstrated that the surface of the rGO was modified leading to increase in the adsorptive capacity to around 80 mg g(-1) after the second regeneration cycle. The morphology of the rGO was observed to change significantly after electrochemical regeneration, suggesting that the rGO based adsorbent materials could only be used for a few cycles.

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

    Energy Technology Data Exchange (ETDEWEB)

    Parreira, N.M.G. [ICEMS-Grupo de Materiais e Engenharia de Superficies, Faculdade de Ciencias e Tecnologia da Universidade de Coimbra-Polo II, 3030-201 Coimbra (Portugal)]. E-mail: nuno.parreira@dem.uc.pt; Carvalho, N.J.M. [ICEMS-Grupo de Materiais e Engenharia de Superficies, Faculdade de Ciencias e Tecnologia da Universidade de Coimbra-Polo II, 3030-201 Coimbra (Portugal)]. E-mail: nuno.carvalho@dem.uc.pt; Cavaleiro, A. [ICEMS-Grupo de Materiais e Engenharia de Superficies, Faculdade de Ciencias e Tecnologia da Universidade de Coimbra-Polo II, 3030-201 Coimbra (Portugal)]. E-mail: albano.cavaleiro@dem.uc.pt

    2006-07-03

    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 {sub O{sub 2}}/p {sub 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 {alpha}-W and {beta}-W{sub 3}O phases were observed (< 30 at.%), and with the increase of oxygen content (30 at.% < O < 67 at.%) the structure became amorphous. A transition region was obtained for oxygen content between 67 at.% and 75 at.%, and when O > 75 at.%, a nanocrystalline (WO{sub 3}) 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 {approx} 23 GPa for pure W down to {approx} 7 GPa for WO{sub 3} 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 {sub c} < 15 N) to the steel substrate because the depositions were carried out intentionally without an adhesion interfacial layer.

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

    Science.gov (United States)

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

    2012-09-01

    Removal of As(V) by adsorption from water solutions was studied using three different synthetic adsorbents. The adsorbents, (a) aluminium nanoparticles (Alu-NPs, polymers (polymer backbones of pure polyacrylamide (MIP-cryo) were of better stability than the amine containing polymer backbone (Alu-cryo). Both composites worked well in the studied pH range of pH 2-8. Adsorption tested in real wastewater spiked with arsenic showed that co-ions (nitrate, sulphate and phosphate) affected arsenic removal for Alu-cryo more than for MIP-cryo. Both composites still adsorbed well in the presence of counter-ions (copper and zinc) present at low concentrations (μg/l). The unchanged and selective adsorption in realistic water observed for MIP-cryo was concluded to be due to a successful imprinting, here controlled using a non-imprinted polymer (NIP). A development of MIP-cryo is needed, considering its low adsorption capacity.

  16. Bacterial adhesion on amorphous and crystalline metal oxide coatings

    Energy Technology Data Exchange (ETDEWEB)

    Almaguer-Flores, Argelia [Facultad de Odontología, División de Estudios de Posgrado e Investigación, Universidad Nacional Autónoma de México, Circuito exterior s/n, Ciudad Universitaria, 04510 México D.F. (Mexico); Silva-Bermudez, Phaedra, E-mail: suriel21@yahoo.com [Unidad de Ingeniería de Tejidos, Terapia Celular y Medicina Regenerativa, Instituto Nacional de Rehabilitación, Calzada México-Xochimilco No. 289, Col. Arenal de Guadalupe, 14389 México D.F. (Mexico); Instituto de Investigaciones en Materiales, Universidad Nacional Autónoma de México, Circuito Exterior s/n, Ciudad Universitaria, 04510 México D.F. (Mexico); Galicia, Rey; Rodil, Sandra E. [Instituto de Investigaciones en Materiales, Universidad Nacional Autónoma de México, Circuito Exterior s/n, Ciudad Universitaria, 04510 México D.F. (Mexico)

    2015-12-01

    Several studies have demonstrated the influence of surface properties (surface energy, composition and topography) of biocompatible materials on the adhesion of cells/bacteria on solid substrates; however, few have provided information about the effect of the atomic arrangement or crystallinity. Using magnetron sputtering deposition, we produced amorphous and crystalline TiO{sub 2} and ZrO{sub 2} coatings with controlled micro and nanoscale morphology. The effect of the structure on the physical–chemical surface properties was carefully analyzed. Then, we studied how these parameters affect the adhesion of Escherichia coli and Staphylococcus aureus. Our findings demonstrated that the nano-topography and the surface energy were significantly influenced by the coating structure. Bacterial adhesion at micro-rough (2.6 μm) surfaces was independent of the surface composition and structure, contrary to the observation in sub-micron (0.5 μm) rough surfaces, where the crystalline oxides (TiO{sub 2} > ZrO{sub 2}) surfaces exhibited higher numbers of attached bacteria. Particularly, crystalline TiO{sub 2}, which presented a predominant acidic nature, was more attractive for the adhesion of the negatively charged bacteria. The information provided by this study, where surface modifications are introduced by means of the deposition of amorphous or crystalline oxide coatings, offers a route for the rational design of implant surfaces to control or inhibit bacterial adhesion. - Highlights: • Amorphous (a) and crystalline (c) TiO{sub 2} and ZrO{sub 2} coatings were deposited. • The atomic ordering influences the coatings surface charge and nano-topography. • The atomic ordering modifies the bacterial adhesion for the same surface chemistry. • S. aureus adhesion was lower on a-TiO{sub 2} and a-ZrO{sub 2} than on their c-oxide counterpart. • E. coli adhesion on a-TiO{sub 2} was lower than on the c-TiO{sub 2}.

  17. The Overcoat Oil Lubrication of Microarc Oxidation Coating on Al Alloy by Liquid Plasma Technique

    Institute of Scientific and Technical Information of China (English)

    LUO Zhuang-zi; ZHANG Zhao-zhu; LIU Wei-ming; WANG Wen-jing; TIAN Jun

    2004-01-01

    Ceramic coatings were deposited on 2Al2 alloy with a 100 kW micro-arc oxidation equipment consisting of a potential adjustable ac power supply and alkali electrolyte. The structure of the micro-arc oxidiation coatings was examined using scanning electron microscopy and transmission electron microscopy. The tribological properties of the coatings sliding against steel under the drop and adsorption lubrication of liquid paraffin were evaluated with a Timken tester. The lower friction coefficient of 0.14 and longer wear life of 2450 m of overcoat were observed for the polished micro-arc oxidation coating of 180μm thick at a sliding speed 2. 50 m/s and load 1500 N. This is because the coating has an interlayer of suitable porosity and thickness, which helps to improve the deposition of lubricants and endure the higher load. In other words, the oil is able to adsorb in the porous holes of the overcoat and provided the lubrication of micro reservoir during friction, and the compact and relatively hard interlayer of oxidation coating is able to support heavy load and prevent the oil lubricating film from damage.

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

    Science.gov (United States)

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

    2011-03-15

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

  19. Effects of sodium tungstate on characteristics of microarc oxidation coatings formed on magnesium alloy in silicate-KOH electrolyte

    Institute of Scientific and Technical Information of China (English)

    DING Jun; LIANG Jun; HU Li-tian; HAO Jing-cheng; XUE Qun-ji

    2007-01-01

    Oxide coatings on AM60B magnesium alloy were prepared using the microarc oxidation(MAO) technique in silicate-KOH electrolyte with addition of 0-6.0 g/L Na2WO4. The MAO processes in base electrolyte with different concentrations of Na2WO4 were studied. The microstructure, compositions and mechanical tribological characteristics of the oxide coatings were also investigated by SEM, XRD, XPS, microhardness analysis and ball-on-disc friction testing, respectively. It is found that the addition of Na2WO4 into the base electrolyte has direct effect on the characteristics of voltage-time curves and breakdown voltage in MAO process. The number of micropores at top of the coating surface is increased by the addition of Na2WO4. The fraction of forsterite Mg2SiO4 in the oxide coating increases with increasing concentration of Na2WO4 in base electrolytes. Furthermore, the microhardness and wear resistance of oxide coatings are enhanced as well.

  20. 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.

  1. Co-precipitation synthesis of nano-composites consists of zinc and tin oxides coatings on glass with enhanced photocatalytic activity on degradation of Reactive Blue 160 KE2B.

    Science.gov (United States)

    Habibi, Mohammad Hossein; Mardani, Maryam

    2015-02-25

    Nano-composite containing zinc oxide-tin oxide was obtained by a facile co-precipitation route using tin chloride tetrahydrate and zinc chloride as precursors and coated on glass by Doctor Blade deposition. The crystalline structure and morphology of composites were evaluated by X-ray diffraction (XRD) and field emission scanning electron microscopy (FESEM). The XRD results showed peaks relative to zinc oxide with hexagonal wurtzite structure and tin oxide with tetragonal structure. FESEM observations showed that the nano-composite consisted of aggregates of particles with an average particle size of 18 nm. The photocatalytic activity of the pure SnO2, pure ZnO, ZnSnO3-Zn2SnO4 and ZnO-SnO2 nano-structure thin films was examined using the degradation of a textile dye Reactive Blue 160 (KE2B). ZnO-SnO2 nano-composite showed enhanced photo-catalytic activity than the pure zinc oxide and tin oxide. The enhanced photo-catalytic activity of the nano-composite was ascribed to an improved charge separation of the photo-generated electron-hole pairs.

  2. 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.

  3. Optimization of operating parameters of novel composite adsorbent for organic pollutants removal from POME using response surface methodology.

    Science.gov (United States)

    Adeleke, A O; Latiff, Ab Aziz Ab; Al-Gheethi, A A; Daud, Zawawi

    2017-05-01

    The present work aimed to develop a novel composite material made up of activated cow bone powder (CBP) as a starting material for reducing chemical oxygen demand (COD) and ammonia-nitrogen (NH3N) from palm oil mill effluent (POME). The optimization of the reduction efficiency was investigated using response surface methodology (RSM). Six independent variables used in the optimization experiments include pH (4-10), speed (0.27-9.66 rcf), contact time (2-24 h), particle size (1-4.35 mm), dilution factor (100-500) and adsorbent dosage (65-125 g/L). The chemical functional groups were determined using Fourier transform irradiation (FTIR). The elemental composition were detected using SEM-EDX, while thermal decomposition was investigated using thermo gravimetric analysis (TGA) in order to determine the effects of carbonization temperature on the adsorbent. The results revealed that the optimal reduction of COD and NH3N from raw POME was observed at pH 10, 50 rpm, within 2 h and 3 mm of particle size as well as at dilution factor of 500 and 125 g L(-1) of adsorbent dosage, the observed and predicted reduction were 89.60 vs. 85.01 and 75.61 vs. 74.04%, respectively for COD and NH3N. The main functional groups in the adsorbent were OH, NH, CO, CC, COC, COH, and CH. The SEM-EDX analysis revealed that the CBP-composite has a smooth surface with high contents of carbon. The activated CBP has very stable temperature profile with no significant weight loss (9.85%). In conclusion, the CBP-composite investigated here has characteristics high potential for the remediation of COD and NH3N from raw POME.

  4. FABRICATION AND PROPERTIES OF SiO2/ZIRCONIUM PHOSPHATE-B2O3-SiO2 ANTI-OXIDATION COATINGS FOR Cf/SiC COMPOSITES

    Directory of Open Access Journals (Sweden)

    Xue-Jin Yang

    2015-09-01

    Full Text Available This paper reports the fabrication of a novel SiO2/zirconium phosphate (ZrP-B2O3-SiO2 double-layer coating on Cf/SiC composites via brushing and sol-gel routes for achieving better anti-oxidation performance. The composition of raw materials and sintering temperature were studied to explore the possibility of development of ZrP coatings to meet the demand for oxidation resistance at high temperature. It was attempted to improve the self-healing ability of coatings via an additional SiO2 layer. Such double-layer coatings developed were characterized by Scanning Electron Microscopy (SEM, Energy Dispersive Spectrometer (EDS, X-ray Diffraction (XRD. The results showed that such coating was composed of a ZrP-B2O3-SiO2 multi-phase inner layer and a SiO2 outer layer. Better oxidation resistance was observed for coatings with higher contents of ZrP powders. After static oxidation at 1500oC for 20 min, the flexural strength of specimens containing 80 wt. % ZrP was up to 314.6 MPa, retaining 89.1 % of the original value of Cf/SiC composites.

  5. 新型SiC-MoSi2/Al-O-Ti炭/炭抗氧化复合涂层的制备及其性能研究%Study on the Preparation and Performance of New SiC-MoSi2/Al-O-Ti Multi Anti-oxidation Coating for C/C Composites

    Institute of Scientific and Technical Information of China (English)

    朱勤旺; 罗瑞盈

    2011-01-01

    A new kind of multi anti-oxidation coating was designed and manufactured by pack cementation and brushing method in this work. The coating was composed of self-healing inner layer, thermal expansion coefficient (CTE) matched intermediate layer and oxygen barrier layer. Morphology and component of the coating were carried out through scanning electron microscopy (SEM), X-Ray diffraction (XRD) and also the properties of anti-oxidation and thermal shock resistance were analyzed at temperatures of 1000 ℃ , 1300 ℃ and 1400 ℃. The results show that the coating can protect the C/C composites for more than 50 h at 1400 ℃ and it is still intact after 20 thermal cycle from room temperature to 1400 ℃.%采用包埋和涂刷法制备出一种新型的炭/炭复合材料抗氧化涂层,它由自愈合内涂层、热膨胀系数匹配过渡层、氧阻挡层三层复合而成.用SEM,XRD对它的组分和形貌进行了表征,同时测试了涂层在1 000,1 300和1 400℃下的抗氧化性能和抗热震性能.实验结果表明:该涂层能在1 400℃下有效保护炭/炭材料达50 h以上,经过20次室温到1 400℃的热震循环后,涂层仍然完整致密.

  6. Water-insoluble sericin/β-cyclodextrin/PVA composite electrospun nanofibers as effective adsorbents towards methylene blue.

    Science.gov (United States)

    Zhao, Rui; Wang, Yong; Li, Xiang; Sun, Bolun; Jiang, Ziqiao; Wang, Ce

    2015-12-01

    A novel water-insoluble sericin/β-cyclodextrin/poly (vinyl alcohol) composite nanofiber adsorbent was prepared by electrospinning and followed by thermal crosslinking for removal of cationic dye methylene blue from aqueous solution. Fourier transform infrared spectroscopy and solubility experiments confirmed that sericin and β-cyclodextrin were incorporated into the nanofibers and the crosslinking reaction occurred successfully. Kinetics, isotherms and thermodynamics analysis were studied for adsorption of methylene blue. The adsorption process is better fitted with the pseudo-second-order model and Langmuir isotherm model. The maximum adsorption capacities are 187.97, 229.89, and 261.10mg/g at the temperatures 293, 313 and 333 K, respectively. Thermodynamic parameters showed that methylene blue adsorption was endothermic and spontaneous. In addition, the fiber membrane adsorbent could be easily separated from dye solution and showed high recyclable removal efficiency. All these results suggest that crosslinked sericin/β-cyclodextrin/poly(vinyl alcohol) composite nanofibers could be potential recyclable adsorbents in dye wastewater treatment.

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

    Science.gov (United States)

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

    2012-08-01

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

  8. 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.

  9. Investigation of anodic oxide coatings on zirconium after heat treatment

    Energy Technology Data Exchange (ETDEWEB)

    Sowa, Maciej [Faculty of Chemistry, Silesian University of Technology, B. Krzywoustego Street 6, 44-100 Gliwice (Poland); Dercz, Grzegorz [Institute of Materials Science, University of Silesia, 75 Pułku Piechoty Street 1 A, 41-500 Chorzów (Poland); Suchanek, Katarzyna [The Henryk Niewodniczanski Institute of Nuclear Physics, Polish Academy of Sciences, Radzikowskiego Street 152, 31-342 Krakow (Poland); Simka, Wojciech, E-mail: wojciech.simka@polsl.pl [Faculty of Chemistry, Silesian University of Technology, B. Krzywoustego Street 6, 44-100 Gliwice (Poland)

    2015-08-15

    Highlights: • Oxide layers prepared via PEO of zirconium were subjected to heat treatment. • Surface characteristics were determined for the obtained oxide coatings. • Heat treatment led to the partial destruction of the anodic oxide layer. • Pitting corrosion resistance of zirconium was improved after the modification. - Abstract: Herein, results of heat treatment of zirconium anodised under plasma electrolytic oxidation (PEO) conditions at 500–800 °C are presented. The obtained oxide films were investigated by means of SEM, XRD and Raman spectroscopy. The corrosion resistance of the zirconium specimens was evaluated in Ringer's solution. A bilayer oxide coatings generated in the course of PEO of zirconium were not observed after the heat treatment. The resulting oxide layers contained a new sublayer located at the metal/oxide interface is suggested to originate from the thermal oxidation of zirconium. The corrosion resistance of the anodised metal was improved after the heat treatment.

  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 μg/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 μg/L, after 75 min at dosage of 5.0 g/L, pH 7.0 and 27 ± 2 °C. For 600 μg/L concentration, the maximum Langmuir monolayer adsorption capacity was found to be 270 μg/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, ΔH°, was -57.782, while the values of ΔG° 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, ΔS°= -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 μg/L concentration. It is interesting to note that the permissible limit of arsenic as per World Health Organization is 10

  11. Transparent Aluminium Oxide Coatings of Polymer Brushes.

    Science.gov (United States)

    Micciulla, Samantha; Duan, XiaoFei; Strebe, Julia; Löhmann, Oliver; Lamb, Robert N; von Klitzing, Regine

    2016-04-11

    A novel method for the preparation of transparent Al2O3 coatings of polymers is presented. An environmental-friendly sol-gel method is employed, which implies mild conditions and low costs. A thermoresponsive brush is chosen as a model surface. X-ray photoelectron spectroscopy is used to characterize the samples during the conversion of the precursor Al(OH)3 into oxide and to prove the mildness of the protocol. The study evidences a relation between lateral homogeneity of alumina and the wettability of the polymer surface by the precursor solution, while morphology and elasticity are dominated by the polymer properties. The study of the swelling behavior of the underneath brush reveals the absence of water uptake, proving the impermeability of the alumina layer. The broad chemical and structural variety of polymers, combined with the robustness of transparent alumina films, makes these composites promising as biomedical implants, protective sheets and components for electric and optical devices.

  12. 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.

  13. Synthesis of citric acid functionalized magnetic graphene oxide coated corn straw for methylene blue adsorption.

    Science.gov (United States)

    Ge, Heyi; Wang, Cuicui; Liu, Shanshan; Huang, Zhen

    2016-12-01

    The citric acid functionalized magnetic graphene oxide coated corn straw (CA-mGOCS) as a new adsorbent was synthesized in this work for the elimination of methylene blue (MB) from waste water. The as-prepared CA-mGOCS was tested by SEM, FTIR, XRD, Roman spectrum, TGA, particle size analyzer, BET and magnetic properties analyzer. Some factors affecting adsorption removal efficiency were explored. As a result, the addition of 5g CS (CA-mGO5CS) had the better adsorption performance than other adsorbents. The pseudo-second-order model and the Freundlich described the adsorption behavior well. The equilibrium adsorption capacity was 315.5mgg(-1) for MB at pH=12 and 298k. The electrostatic incorporation as well as hydrophobic interactions between CA-mGO5CS and MB determined the favourable adsorption property. Besides, the thermodynamic studies results ΔGadsorption was a spontaneous, exothermic and randomness decrease process. Finally, reusability studies imply that CA-mGO5CS has an excellent reproducibility.

  14. Novel Fe/glass composite adsorbent and its property for arsenic(V) removal

    Institute of Scientific and Technical Information of China (English)

    Wang Ying; Zhu Kongjun; Wang Fen; Yanagisawa Kazumichi

    2009-01-01

    An effective adsorbent for arsenic removal was synthesized by hydrothermal treatment of waste glass powder (HGP), followed by loading iron(III) oxyhydorxide on the surface of waste glass powder (GP). The ?Si-O-H group was formed on the surface of GP and the specific surface area of GP powder was slightly increased after hydrothermal treatment. FeOOH was loaded on the surface of HGP by the hydrolysis of FeCl3. The formation conditions of FeOOH were also investigated. The ability of this new adsorbent for arsenic removal was tested. The results indicate that the highest arsenic removal efficiency is about 97% for 1 mg/L As(V) solution at pH 6 and keeping time 2h.

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

    Energy Technology Data Exchange (ETDEWEB)

    Mimura, Hitoshi [Tohoku Univ., Sendai (Japan); Onodera, Yoshio

    2001-03-01

    Radionuclides in high-level liquid waste are classified into four groups such as transuranic elements (TRU) group, technetium - platinum group, strontium - cesium group, and others group. Cesium showed high adsorption selectivity to AMP [(NH{sub 4}){sub 3}PO{sub 4}12MoO{sub 3}3H{sub 2}O], AWP [(NH{sub 4}){sub 3}PO{sub 4}12WO{sub 3}3H{sub 2}O], and KNiFC(K{sub 2-x}Ni{sub x/2}[NiFe(CN){sub 6}]nH{sub 2}O). These inorganic ion exchangers with selectivity of cesium are possible to be supported by porous materials and to be immobilized by polymer. Some examples (AMP/Al{sub 2}O{sub 3}, AMP/alginate, and KNiFC/zeolite) are shown in this paper. KCuFC/alginate can adsorb Pd into KCuFC, Ru into alginate, but can not adsorb Rh. Accordingly, platinum metals (Pd, Ru and Rh) are separated by it. Pd, Ru and Rh in their mixed solution are mutually separated by using Cyanex 302/alginate and chromatography. Eu and Am adsorbed by Cyanex 301-alginate acid gel microcapsule were separated by gradient elution. Then, 98.8% of Eu and 91.3% of Am were eluted at pH 2 and pH 1, respectively. (S.Y.)

  16. Pore structure of new composite adsorbent SiO2·xH2O·yCaCl2 with high uptake of water from air

    Institute of Scientific and Technical Information of China (English)

    刘业凤; 王如竹

    2003-01-01

    A new composite adsorbent SiO2@xH2O@yCaCl2 which is composed of macro-porous silica gel and calcium chloride is introduced. In order to analyze its adsorption theory, adsorption and desorption isotherms, BET surface areas, pore volumes and average pore diameters of macro-porous silica gel and four composite adsorbent samples with different CaCl2 content are measured using SEM and Asap2010 apparatus. From the adsorption isotherms, desorption isotherms and lag loops, it can be deduced that the main pore structure in macro-porous silica gel and the new composite adsorbent have two shapes: taper with one top open and taper or hyperbolic taper with both ends open. Based on the analysis of pore diameter distribution and lag loop, a sketch map showing calcium chloride filled in pore of macro-porous silica gel is presented. The adsorption isotherms at 25℃ are measured. Experimental results show that the new composite adsorbent can adsorb more water than common adsorbents (macro-porous silica gel, micro-porous silica gel and synthetic zeolite 13X). In the light of the results of pore structure, adsorption isotherms and lyolysis phenomenon are analyzed.

  17. 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.

  18. Preparation and Characterization of Plasma-Sprayed Ultrafine Chromium Oxide Coatings

    Institute of Scientific and Technical Information of China (English)

    LIN Feng; JIANG Xianliang; YU Yueguang; ZENG Keli; REN Xianjing; LI Zhenduo

    2007-01-01

    Ultrafine chromium oxide coatings were prepared by plasma spraying with ultrafine feedstock. Processing parameters of plasma spraying were optimized. Optical microscope (OM) was used to observe the microstructure of the ultrafine chromium oxide coatings. Scanning electron microscopy (SEM) was used to observe the morphology and particle size of ultrafine powder feedstock as well as to examine the microstructure of the chromium oxide coating. In addition, hardness and bonding strength of the ultrafine chromium oxide coatings were measured.The results showed that the optimized plasma spraying parameters were suitable for ultrafine chromium oxide coating and the properties and microstructure of the optimized ultrafine chromium oxide coating were superior compared to conventional chromium oxide wear resistant coatings.

  19. Mesoporous silica/polyacrylamide composite: Preparation by UV-graft photopolymerization, characterization and use as Hg(II) adsorbent

    Science.gov (United States)

    Saad, Ali; Bakas, Idriss; Piquemal, Jean-Yves; Nowak, Sophie; Abderrabba, Manef; Chehimi, Mohamed M.

    2016-03-01

    MCM-41 ordered mesoporous silica was prepared, aminosilanized and grafted with polyacrylamide (PAAM) through in situ radical photopolymerization process. The resulting composite, denoted PAAM-NH2-MCM-41, the calcined and silanized reference MCM-41s were characterized by Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), thermogravimetric analysis (TGA), X-ray photoelectron spectroscopy (XPS), transmission electron microscopy (TEM), scanning electron microscopy (SEM) and N2 physisorption at 77 K. These complementary techniques brought strong supporting evidence for the silanization process followed by PAAM grafting. The surface composition was found to be PAAM-rich as judged by XPS. The composite was then employed for the uptake of Hg(II) from aqueous solutions. Adsorption was monitored versus pH, time, and temperature. The maximum adsorption capacity at 25 °C and pH 5.2 was 177 mg g-1. Kinetically, the equilibrium was reached within 60 min for a 100 mg L-1 mercury solution. The adsorption of Hg(II) on PAAM-NH2-MCM-41 composites followed second order kinetics. Thermodynamic parameters suggested that the favorable adsorption process is exothermic in nature and the adsorption is ascribed to a decrease in the degree of freedom of adsorbed ions which results in the entropy change. This work conclusively shows that mesoporous silica-polymer hybrid metal ion adsorbents (with robust silica-polymer interface) can be prepared in a simple way by in situ radical photopolymerization in the presence of aminosilanized silica acting as a support and a macro-hydrogen donor simultaneously.

  20. Mesoporous silica/polyacrylamide composite: Preparation by UV-graft photopolymerization, characterization and use as Hg(II) adsorbent

    Energy Technology Data Exchange (ETDEWEB)

    Saad, Ali, E-mail: ali.saad8803@gmail.com [Laboratory of Materials, Molecules and Applications, IPEST, University of Carthage, Sidi Bou Said road, B.P. 51, 2070 La Marsa (Tunisia); Faculté des Sciences de Tunis, Université El Manar, PO Box 248, El Manar II, 2092 Tunis (Tunisia); Univ Paris Diderot, Sorbonne Paris Cité, ITODYS, UMR 7086, CNRS, F-75013 Paris (France); Bakas, Idriss [Univ Paris Diderot, Sorbonne Paris Cité, ITODYS, UMR 7086, CNRS, F-75013 Paris (France); Laboratoire AQUAMAR, Equipe Matériaux Photocatalyse et Environnement, Faculté des Sciences, Université Ibn Zohr, B.P. 8106, Cité Dakhla, Agadir (Morocco); Piquemal, Jean-Yves; Nowak, Sophie [Univ Paris Diderot, Sorbonne Paris Cité, ITODYS, UMR 7086, CNRS, F-75013 Paris (France); Abderrabba, Manef, E-mail: abderrabbamanef@gmail.com [Laboratory of Materials, Molecules and Applications, IPEST, University of Carthage, Sidi Bou Said road, B.P. 51, 2070 La Marsa (Tunisia); Chehimi, Mohamed M., E-mail: chehimi@icmpe.cnrs.fr [Univ Paris Diderot, Sorbonne Paris Cité, ITODYS, UMR 7086, CNRS, F-75013 Paris (France); Université Paris Est, ICMPE (UMR7182), CNRS, UPEC, F-94320 Thiais (France)

    2016-03-30

    Graphical abstract: - Highlights: • Mesoporous silica/polyacrylamide nanocomposite adsorbent was prepared by UV-graft polymerization. • Polyacrylamide was successfully grafted onto the silanized mesoporous silica. • The Hg(II) adsorption capacity of the nanocomposite was as high as 177 mg g{sup −1} after 1 h at RT. • Adsorption process was found to fit pseudo second order kinetics and exothermic. - Abstract: MCM-41 ordered mesoporous silica was prepared, aminosilanized and grafted with polyacrylamide (PAAM) through in situ radical photopolymerization process. The resulting composite, denoted PAAM-NH{sub 2}-MCM-41, the calcined and silanized reference MCM-41s were characterized by Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), thermogravimetric analysis (TGA), X-ray photoelectron spectroscopy (XPS), transmission electron microscopy (TEM), scanning electron microscopy (SEM) and N{sub 2} physisorption at 77 K. These complementary techniques brought strong supporting evidence for the silanization process followed by PAAM grafting. The surface composition was found to be PAAM-rich as judged by XPS. The composite was then employed for the uptake of Hg(II) from aqueous solutions. Adsorption was monitored versus pH, time, and temperature. The maximum adsorption capacity at 25 °C and pH 5.2 was 177 mg g{sup −1}. Kinetically, the equilibrium was reached within 60 min for a 100 mg L{sup −1} mercury solution. The adsorption of Hg(II) on PAAM-NH{sub 2}-MCM-41 composites followed second order kinetics. Thermodynamic parameters suggested that the favorable adsorption process is exothermic in nature and the adsorption is ascribed to a decrease in the degree of freedom of adsorbed ions which results in the entropy change. This work conclusively shows that mesoporous silica–polymer hybrid metal ion adsorbents (with robust silica–polymer interface) can be prepared in a simple way by in situ radical photopolymerization in the presence of

  1. 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

    2015-03-02

    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.

  2. INVESTIGATION ON STRUCTURE, COMPOSITION, AND REGENERATION BEHAVIOR OF INDUSTRIAL S ZORB ADSORBENT%S Zorb工业吸附剂结构、组成及再生行为研究

    Institute of Scientific and Technical Information of China (English)

    徐莉; 邹亢; 徐广通; 毛安国

    2013-01-01

    The variations of structure,composition,and chemical properties of S Zorb adsorbent during the industrial regeneration process were studied.The structure and composition of adsorbent were characterized by XRD and FT-IR analysis.The chemical state changes of sulfur atom on the surface of adsorbent were examined by XPS.The formations of SO42-compounds in bulk phase of adsorbent were discussed,using the XRD phase quantitative analysis combined with the carbon and sulfur content analysis.The morphology of adsorbent was characterized by SEM analysis.It is found that the desulfurization activity of adsorbent is deeply dependent on both the content of zinc silicate phase and the regeneration rate of ZnS phase.The regeneration rate of ZnS phase increases with increasing of the relative content of oxygen during the regeneration process with increase of the by-product ZnSO4 content at the same time.The morphology and particle size of adsorbent are not changed after regeneration.%探讨了系列S Zorb吸附剂在工业再生过程中结构、组成和性质的变化规律.利用XRD、FT-IR表征了系列工业待生和再生吸附剂的结构和组成;利用XPS分析了吸附剂表面硫元素形态的变化规律;利用XRD物相定量结果和碳硫分析结果,探讨了吸附剂体相中硫酸根化合物的形成规律;利用SEM分析表征吸附剂的形貌.研究发现吸附剂的脱硫活性受硅酸锌含量和硫化锌再生率的协同影响,通过提高再生过程中氧气的相对含量可以显著提高硫化锌的再生率,但是会增加副产物硫酸锌的含量.再生前后吸附剂形貌和粒径均未发生明显变化.

  3. Vertically aligned WO₃ nanowire arrays grown directly on transparent conducting oxide coated glass: synthesis and photoelectrochemical properties.

    Science.gov (United States)

    Su, Jinzhan; Feng, Xinjian; Sloppy, Jennifer D; Guo, Liejin; Grimes, Craig A

    2011-01-12

    Photocorrosion stable WO(3) nanowire arrays are synthesized by a solvothermal technique on fluorine-doped tin oxide coated glass. WO(3) morphologies of hexagonal and monoclinic structure, ranging from nanowire to nanoflake arrays, are tailored by adjusting solution composition with growth along the (001) direction. Photoelectrochemical measurements of illustrative films show incident photon-to-current conversion efficiencies higher than 60% at 400 nm with a photocurrent of 1.43 mA/cm(2) under AM 1.5G illumination. Our solvothermal film growth technique offers an exciting opportunity for growth of one-dimensional metal oxide nanostructures with practical application in photoelectrochemical energy conversion.

  4. 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.

  5. Formation and composition of adsorbates on hydrophobic carbon surfaces from aqueous laccase-maltodextrin mixture suspension

    Science.gov (United States)

    Corrales Ureña, Yendry Regina; Lisboa-Filho, Paulo Noronha; Szardenings, Michael; Gätjen, Linda; Noeske, Paul-Ludwig Michael; Rischka, Klaus

    2016-11-01

    A robust procedure for the surface bio-functionalization of carbon surfaces was developed. It consists on the modification of carbon materials in contact with an aqueous suspension of the enzyme laccase from Trametes versicolor and the lyophilization agent maltodextrin, with the pH value adjusted close to the isoelectric point of the enzyme. We report in-situ investigations applying Quartz Crystal Microbalance with Dissipation (QCM-D) for carbon-coated sensor surfaces and, moreover, ex-situ measurements with static contact angle measurements, X-ray Photoelectron Spectroscopy (XPS) and Scanning Force Microscopy (SFM) for smooth Highly Oriented Pyrolytic Graphite (HOPG) substrates, for contact times between the enzyme formulation and the carbon material surface ranging from 20 s to 24 h. QCM-D studies reveals the formation of rigid layer of biomaterial, a few nanometers thin, which shows a strongly improved wettability of the substrate surface upon contact angle measurements. Following spectroscopic characterization, these layers are composed of mixtures of laccase and maltodextrin. The formation of these adsorbates is attributed to attractive interactions between laccase, the maltodextrin-based lyophilization agent and the hydrophobic carbon surfaces; a short-term contact between the aqueous laccase mixture suspension and HOPG surfaces is shown to merely result in de-wetting patterns influencing the results of contact angle measurements. The new enzyme-based surface modification of carbon-based materials is suggested to be applicable for the improvement of not only the wettability of low energy substrate surfaces with fluid formulations like coatings or adhesives, but also their adhesion in contact with hardened polymers.

  6. Formation and composition of adsorbates on hydrophobic carbon surfaces from aqueous laccase-maltodextrin mixture suspension

    Energy Technology Data Exchange (ETDEWEB)

    Corrales Ureña, Yendry Regina, E-mail: yendry386@hotmail.com [UNESP São Paulo State University, Av. Eng. Luiz Edmundo Carrijo Coube, 14-01, Bauru, São Paulo (Brazil); Fraunhofer Institute for Manufacturing Technology and Advanced Materials IFAM, Wiener Strasse 12, 28359 Bremen (Germany); Lisboa-Filho, Paulo Noronha [UNESP São Paulo State University, Av. Eng. Luiz Edmundo Carrijo Coube, 14-01, Bauru, São Paulo (Brazil); Szardenings, Michael [Fraunhofer Institute for Cell Therapy and Immunology IZI, Perlickstrasse 1, 04103 Leipzig (Germany); Gätjen, Linda; Noeske, Paul-Ludwig Michael; Rischka, Klaus [Fraunhofer Institute for Manufacturing Technology and Advanced Materials IFAM, Wiener Strasse 12, 28359 Bremen (Germany)

    2016-11-01

    Highlights: • Less than 10 nm layer formed on carbon based materials composed by laccase and maltodextrin. • Improvement of the wettability of carbon based materials. • A protein-polysaccharide biofilm layer formation at solid liquid interface. • Stable layers formed under buffer and water rinsing. - Abstract: A robust procedure for the surface bio-functionalization of carbon surfaces was developed. It consists on the modification of carbon materials in contact with an aqueous suspension of the enzyme laccase from Trametes versicolor and the lyophilization agent maltodextrin, with the pH value adjusted close to the isoelectric point of the enzyme. We report in-situ investigations applying Quartz Crystal Microbalance with Dissipation (QCM-D) for carbon-coated sensor surfaces and, moreover, ex-situ measurements with static contact angle measurements, X-ray Photoelectron Spectroscopy (XPS) and Scanning Force Microscopy (SFM) for smooth Highly Oriented Pyrolytic Graphite (HOPG) substrates, for contact times between the enzyme formulation and the carbon material surface ranging from 20 s to 24 h. QCM-D studies reveals the formation of rigid layer of biomaterial, a few nanometers thin, which shows a strongly improved wettability of the substrate surface upon contact angle measurements. Following spectroscopic characterization, these layers are composed of mixtures of laccase and maltodextrin. The formation of these adsorbates is attributed to attractive interactions between laccase, the maltodextrin-based lyophilization agent and the hydrophobic carbon surfaces; a short-term contact between the aqueous laccase mixture suspension and HOPG surfaces is shown to merely result in de-wetting patterns influencing the results of contact angle measurements. The new enzyme-based surface modification of carbon-based materials is suggested to be applicable for the improvement of not only the wettability of low energy substrate surfaces with fluid formulations like coatings

  7. Efficient adsorption of both methyl orange and chromium from their aqueous mixtures using a quaternary ammonium salt modified chitosan magnetic composite adsorbent.

    Science.gov (United States)

    Li, Kun; Li, Pei; Cai, Jun; Xiao, Shoujun; Yang, Hu; Li, Aimin

    2016-07-01

    A quaternary ammonium salt modified chitosan magnetic composite adsorbent (CS-CTA-MCM) was prepared by combination of Fe3O4 nanoparticles. Various techniques were used to characterize the molecular structure, surface morphology, and magnetic feature of this composite adsorbent. CS-CTA-MCM was employed for the removal of Cr(VI) and methyl orange (MO), an anionic dye, from water in respective single and binary systems. Compared with chitosan magnetic adsorbent (CS-MCM) without modification, CS-CTA-MCM shows evidently improved adsorption capacities for both pollutants ascribed to the additional quaternary ammonium salt groups. Based on the adsorption equilibrium study, MO bears more affinity to CS-CTA-MCM than Cr(VI) causing a considerable extent of preferential adsorption of dye over metal ions in their aqueous mixture. However, at weak acidic solutions, Cr(VI) adsorption is evidently improved due to more efficient Cr(VI) forms, i.e. dichromate and monovalent chromate, binding to this chitosan-based adsorbent. Thus chromium could be efficient removal together with MO at suitable pH conditions. The adsorption isotherms and kinetics indicate that adsorptions of Cr(VI) and MO by CS-CTA-MCM both follow a homogeneous monolayer chemisorption process. This magnetic adsorbent after saturated adsorption could be rapidly separated from water and easily regenerated using dilute NaOH aqueous solutions then virtually reused with little adsorption capacity loss.

  8. A novel modified graphene oxide/chitosan composite used as an adsorbent for Cr(VI) in aqueous solutions.

    Science.gov (United States)

    Zhang, Li; Luo, Hanjin; Liu, Peipei; Fang, Wei; Geng, Junjie

    2016-06-01

    A novel adsorbent for removal of hexavalent chromium (Cr(VI)) from aqueous solutions has been successfully prepared by modifying graphene oxide/chitosan composite with disodium ethylenediaminetetraacetate (EDTA-2Na) (GEC). This modified composite was characterized by various technologies; including scanning electron microscopy (SEM), Transmission Electron Microscopy (TEM), X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FT-IR). Batch adsorption experiments were carried out to evaluate the adsorption of Cr(VI) by GEC under different conditions. The results indicate that the adsorption of Cr(VI) on GEC was highly pH-dependent, with the highest adsorption capacity (86.17mg/g) occurring at pH 2. The kinetics of adsorption exhibited pseudo-second-order behavior. The adsorption data were well described by the Freundlich isotherm model. The adsorption capacity increased with increasing temperature. The calculated thermodynamic parameters indicate that the adsorption is a spontaneous, endothermic and feasible process. The further regeneration experiments showed the adsorption capacity of GEC for Cr(VI) decreased 5% after 7 times reuse, indicating the potential of the as-prepared material for practical application.

  9. An electrochemical approach to graphene oxide coated sulfur for long cycle life

    Science.gov (United States)

    Moon, Joonhee; Park, Jungjin; Jeon, Cheolho; Lee, Jouhahn; Jo, Insu; Yu, Seung-Ho; Cho, Sung-Pyo; Sung, Yung-Eun; Hong, Byung Hee

    2015-07-01

    Owing to the possibilities of achieving high theoretical energy density and gravimetric capacity, sulfur has been considered as a promising cathode material for rechargeable lithium batteries. However, sulfur shows rapid capacity fading due to the irreversible loss of soluble polysulfides and the decrease in active sites needed for conducting agents. Furthermore, the low electrical conductivity of sulfur hampers the full utilization of active materials. Here we report that graphene oxide coated sulfur composites (GO-S/CB) exhibit improved electrochemical stability as well as enhanced rate performance, evidenced by various electrochemical analyses. The cyclic voltammetry and the galvanostatic cycling analysis revealed that the GO plays key roles in homogenizing the nanocomposite structures of the electrodes, in improving the electrochemical contact, and in minimizing the loss of soluble polysulfide intermediates. An electrochemical impedance spectroscopy analysis also confirms the enhanced structural stability of the GO-S/CB composites after battery operation. As a result, the GO-S/CB exhibited excellent cycle stability and specific capacity as high as ~723.7 mA h g-1 even after 100 cycles at 0.5 C.Owing to the possibilities of achieving high theoretical energy density and gravimetric capacity, sulfur has been considered as a promising cathode material for rechargeable lithium batteries. However, sulfur shows rapid capacity fading due to the irreversible loss of soluble polysulfides and the decrease in active sites needed for conducting agents. Furthermore, the low electrical conductivity of sulfur hampers the full utilization of active materials. Here we report that graphene oxide coated sulfur composites (GO-S/CB) exhibit improved electrochemical stability as well as enhanced rate performance, evidenced by various electrochemical analyses. The cyclic voltammetry and the galvanostatic cycling analysis revealed that the GO plays key roles in homogenizing the

  10. 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 (446.25 mg g(-1) for MO and 417.38 mg g(-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.

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

    Science.gov (United States)

    Dastbaz, Abolfazl.; Keshtkar, Ali Reza.

    2014-02-01

    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.

  12. 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.

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

    Science.gov (United States)

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

    2014-03-19

    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.

  14. Protective Oxide Coating for Ionic Conductive Solid Electrolyte Interphase.

    Science.gov (United States)

    Kim, Yong Su; Kim, Seong Heon; Kim, Gyusung; Heo, Sung; Mun, Jinsoo; Han, Sungsoo; Jung, Heechul; Kyoung, Yong Koo; Yun, Dong Jin; Baek, Woon Joong; Doo, Seokgwang

    2016-11-16

    To employ Li-based batteries to their full potential in a wide range of energy-storage applications, their capacity and performance stability must be improved. Si is a viable anode material for Li-based batteries in electric vehicles due to its high theoretical capacity and good economic feasibility. However, it suffers from physical and chemical degradation, leading to unstable electrochemical performance and preventing its incorporation in new Li-based battery systems. Herein, we applied a poly(vinyl alcohol)-PO4 protective coating for Si-graphite anodes and confirmed an improvement in the electrochemical performance. The experimental results revealed that the polymer acts as a binder to alleviate the pulverization of the electrode. Furthermore, the oxide coating reduces the loss of Li2O, which has high ionic conductivity, during operation, resulting in the formation of a stable solid electrolyte interphase. Our findings suggest that a stable and ion-conducting anode/interphase can be developed by applying an oxide and polymer coating in combined approach. Therefore, this study is expected to provide a basis for the further development and design of high-performance Li-based battery systems.

  15. Adsorption of HSA, IgG and laminin-1 on model titania surfaces--effects of glow discharge treatment on competitively adsorbed film composition.

    Science.gov (United States)

    Santos, Olga; Svendsen, Ida E; Lindh, Liselott; Arnebrant, Thomas

    2011-10-01

    This study investigated the effect of glow discharge treatment of titania surfaces on plasma protein adsorption, by means of ellipsometry and mechanically assisted SDS elution. The adsorption and film elution of three plasma proteins, viz. human serum albumin (HSA), human immunoglobulin G (IgG) and laminin-1, as well as competitive adsorption from a mixture of the three proteins, showed that the adsorbed amount of the individual proteins after 1 h increased in the order HSA adsorbed films. No difference in the total adsorbed amounts of individual proteins, or from the mixture, was observed between untreated and glow discharge treated titania surfaces. However, the composition of the adsorbed films from the mixture differed between the untreated and glow discharge treated substrata. On glow discharge-treated titania the fraction of HSA increased, the fraction of laminin-1 decreased and the fraction of IgG was unchanged compared to the adsorption on the untreated titania, which was attributed to protein-protein interactions and competitive/associative adsorption behaviour.

  16. Lead isotopes in iron and manganese oxide coatings and their use as an exploration guide for concealed mineralization

    Science.gov (United States)

    Gulson, B.L.; Church, S.E.; Mizon, K.J.; Meier, A.L.

    1992-01-01

    Lead isotopes from Fe and Mn oxides that coat stream pebbles from around the Mount Emmons porphyry molybdenum deposit in Colorado were studied to assess the feasibility of using Pb isotopes to detect concealed mineral deposits. The Fe/Mn oxide coatings were analyzed to determine their elemental concentrations using ICP-AES. The Pb isotope compositions of solutions from a selected suite of samples were measured, using both thermal ionization and ICP mass spectrometry, to compare results determined by the two analytical methods. Heavy mineral concentrates from the same sites were also analyzed to compare the Pb isotope compositions of the Fe/Mn coatings with those found in panned concentrates. The Fe/Mn and 206Pb/204Pb ratios of the oxide coatings are related to the lithology of the host rocks; Fe/Mn oxide coatings on pebbles of black shale have higher Fe/Mn values than do the coatings on either sandstone or igneous rocks. The shale host rocks have a more radiogenic signature (e.g. higher 206Pb/ 204Pb) than the sandstone or igneous host rocks. The Pb isotope data from sandstone and igneous hosts can detect concealed mineralized rock on both a regional and local scale, even though there are contributions from: (1) metals from the main-stage molybdenite ore deposit; (2) metals from the phyllic alteration zone which has a more radiogenic Pb isotope signature reflecting hydrothermal leaching of Pb from the Mancos Shale; (3) Pb-rich base metal veins with a highly variable Pb isotope signature; and (4) sedimentary country rocks which have a more radiogenic Pb isotope signature. An investigation of within-stream variation shows that the Pb isotope signature of the molybdenite ore zone is retained in the Fe/Mn oxide coatings and is not camouflaged by contributions from Pb-rich base-metal veins that crop out upstream. In another traverse, the Pb isotope data from Fe/Mn oxide coatings reflect a complex mixing of Pb from the molybdenite ore zone and its hornfels margin, Pb

  17. Synthesis and characterization of 1-Methyl-3-Methoxysilyl Propyl Imidazolium Chloride - mesoporous silica composite as adsorbent for dehydration in industrial processes

    Energy Technology Data Exchange (ETDEWEB)

    Lievano, Javier F. Plata; Diaz, Luz A. Carreno, E-mail: lcarreno@uis.edu.co [Universidad Industrial de Santander (Colombia)

    2016-07-15

    Ionic liquid - mesoporous silica composite was synthesized as a new adsorbent for dehydration in industrial processes. An ionic liquid (IL) with proved dehydration properties has been covalently anchored to mesoporous silica. The parameters of the synthesis were studied to produce a solid and stable composite. The material was then characterized by SEM, BET, FTIR, NMR, Raman, XRD, XRF, MALDI and LDI confirming the presence of a covalent bond between the ionic liquid and the solid matrix. Evaluations have shown that the material kept the IL dehydration property. (author)

  18. RhB Adsorption Performance of Magnetic Adsorbent Fe3O4/RGO Composite and Its Regeneration through A Fenton-like Reaction

    Institute of Scientific and Technical Information of China (English)

    Yalin Qin; Mingce Long∗; Beihui Tan; Baoxue Zhou

    2014-01-01

    Adsorption is one of the most effective technologies in the treatment of colored matter containing wastewater. Graphene related composites display potential to be an effective adsorbent. However, the adsorp-tion mechanism and their regeneration approach are still demanding more efforts. An effective magnetically separable absorbent, Fe3O4 and reduced graphene oxide (RGO) composite has been prepared by an in situ coprecipitation and reduction method. According to the characterizations of TEM, XRD, XPS, Raman spectra and BET analyses, Fe3O4 nanoparticles in sizes of 10-20 nm are well dispersed over the RGO nanosheets, re-sulting in a highest specific area of 296.2 m2/g. The rhodamine B adsorption mechanism on the composites was investigated by the adsorption kinetics and isotherms. The isotherms are fitting better by Langmuir model, and the adsorption kinetic rates depend much on the chemical components of RGO. Compared to active carbon, the composite shows 3.7 times higher adsorption capacity and thirty times faster adsorption rates. Furthermore, with Fe3O4 nanoparticles as the in situ catalysts, the adsorption performance of composites can be restored by carrying out a Fenton-like reaction, which could be a promising regeneration way for the adsorbents in the organic pollutant removal of wastewater.

  19. 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.

  20. Corrosion evaluation of zirconium doped oxide coatings on aluminum formed by plasma electrolytic oxidation.

    Science.gov (United States)

    Bajat, Jelena; Mišković-Stanković, Vesna; Vasilić, Rastko; Stojadinović, Stevan

    2014-01-01

    The plasma electrolytic oxidation (PEO) of aluminum in sodium tungstate (Na(2)WO(4) · (2)H(2)O) and Na(2)WO(4) · (2)H(2)O doped with Zr was analyzed in order to obtain oxide coatings with improved corrosion resistance. The influence of current density in PEO process and anodization time was investigated, as well as the influence of Zr, with the aim to find out how they affect the chemical content, morphology, surface roughness, and corrosion stability of oxide coatings. It was shown that the presence of Zr increases the corrosion stability of oxide coatings for all investigated PEO times. Evolution of EIS spectra during the exposure to 3% NaCl, as a strong corrosive agent, indicated the highest corrosion stability for PEO coating formed on aluminum at 70 mA/cm(2) for 2 min in a zirconium containing electrolyte.

  1. Titanium-nitride-oxide-coated coronary stents: insights from the available evidence.

    Science.gov (United States)

    Karjalainen, Pasi P; Nammas, Wail

    2016-11-12

    Coating of stent surface with a biocompatible material is suggested to improve stent safety profile. A proprietary process was developed to coat titanium-nitride-oxide on the stent surface, based on plasma technology that uses the nano-synthesis of gas and metal. Preclinical in vitro and in vivo investigation confirmed blood compatibility of titanium (nitride-) oxide films. Titanium-nitride-oxide-coated stents demonstrated a better angiographic outcome, compared with bare-metal stents at mid-term follow-up; however, they failed to achieve non-inferiority for angiographic outcome versus second-generation drug-eluting stents. Observational studies showed adequate clinical outcome at mid-term follow-up. Non-randomized studies showed an outcome of titanium-nitride-oxide-coated stents comparable to - or better than - first-generation drug-eluting stents at long-term follow-up. Two randomized controlled trials demonstrated comparable efficacy outcome, and a better safety outcome of titanium-nitride-oxide-coated stents versus drug-eluting stents at long-term follow-up. Evaluation by optical coherence tomography at mid-term follow-up revealed better neointimal strut coverage associated with titanium-nitride-oxide-coated stents versus drug-eluting stents; yet, neointimal hyperplasia thickness was greater. Key messages Stents coated with titanium-nitride-oxide demonstrated biocompatibility in preclinical studies: they inhibit platelet and fibrin deposition, and reduce neointimal growth. In observational and non-randomized studies, titanium-nitride-oxide-coated stents were associated with adequate safety and efficacy outcome. In randomized trials of patients with acute coronary syndrome, titanium-nitride-oxide-coated stents were associated with a better safety outcome, compared with drug-eluting stents; efficacy outcome was comparable.

  2. 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.

  3. 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.

  4. Manganese-oxide-coated redox bars as an indicator of reducing conditions in soils.

    Science.gov (United States)

    Dorau, Kristof; Mansfeldt, Tim

    2015-03-01

    Identification of reducing conditions in soils is of concern not only for pedogenesis but also for nutrient and pollutant dynamics. We manufactured manganese (Mn)-oxide-coated polyvinyl chloride bars and proved their suitability for the identification of reducing soil conditions. Birnessite was synthesized and coated onto white polyvinyl chloride bars. The dark brown coatings were homogenous and durable. As revealed by microcosm devices with adjusted redox potentials (E), under oxidizing conditions (E ∼450 mV at pH 7) there was no Mn-oxide removal. Reductive dissolution of Mn-oxides, which is expressed by the removal of the coatings, started under weakly reducing conditions (E ∼175 mV) and was more intensive under moderately reducing conditions (∼80 mV). According to thermodynamics, the removal of Mn-oxide coatings (225 mm d) exceeded the removal of iron (Fe)-oxide coatings (118 mm d) in soil column experiments. This was confirmed in a soil with a shallow and strongly fluctuating water table where both types of redox bars were inserted. Consequently, it was possible to identify reducing conditions in soils using Mn-oxide-coated bars. We recommend this methodology for short-term monitoring because tri- and tetravalent Mn is the preferred electron acceptor compared with trivalent Fe, and this additionally offers the possibility of distinguishing between weakly and moderately reducing conditions. If dissolved Fe is abundant in soils, the possibility of nonenzymatic reduction of Mn has to be taken into account.

  5. CoxFe1-x oxide coatings on metallic interconnects for solid oxide fuel cells

    Science.gov (United States)

    Shen, Fengyu; Lu, Kathy

    2016-10-01

    In order to improve the performance of Cr-containing steel as an interconnect material for solid oxide fuel cells, CoFe alloy coatings with Co:Fe ratios of 9:1, 8:2, 7:3, 6:4, and 5:5 are deposited by electrodeposition and then oxidized to CoxFe1-x oxide coatings with a thickness of ∼6 μm as protective layers on the interconnect. The area specific resistance of the coated interconnect increases with the Fe content. Higher Co content oxide coatings are more effective in limiting the growth of the chromia scale while all coatings are effective in inhibiting Cr diffusion and evaporation. With the Co0.8Fe0.2 oxide coated interconnect, the electrochemical performance of the Sm0.5Sr0.5Co0.2Fe0.8O3 cathode is improved. Only 1.54 atomic percentage of Cr is detected on the surface of the Sm0.5Sr0.5Co0.2Fe0.8O3 cathode while no Cr is detected 0.66 μm or more into the cathode. CoxFe1-x oxide coatings are promising candidates for solid oxide fuel cell interconnects with the advantage of using existing cathode species for compatibility and performance enhancement.

  6. Evaluating the performance of modified adsorbent of zero valent iron nanoparticles – Chitosan composite for arsenate removal from aqueous solutions

    Directory of Open Access Journals (Sweden)

    K Yaghmaeian

    2016-03-01

    Full Text Available Background and Objective: Arsenic is one of the most toxic pollutants in groundwater and surface water. Arsenic could have lots of adverse impacts on human health. Therefore, access to new technologies is required to achieve the arsenic standard. Materials and Methods: The present study was conducted at laboratory scale in non-continuous batches. The adsorbent of zero-valent iron nanoparticles -Chitosan was produced through reducing ferric iron by sodium borohydride (NaBH4 in the presence of chitosan as a stabilizer. At first, the effect of various parameters such as contact time (5-120 min, pH (3-10, adsorbent dose (0.3-3.5 g/L and initial concentration of arsenate (2-10 mg/L were investigated on process efficiency. Then optimum conditions in terms of contact time, pH, adsorbent dose and initial concentration of arsenate were determined by RSM method. Freundlich and Langmuir isotherm model equilibrium constant, pseudo-first and second order kinetic constants were calculated. The residual arsenate was measured y using ICP-AES. Results: The optimum values based on RSM for pH, absorbent dose, contact time, and initial concentration of arsenate were 7.16, 3.04 g/L, 91.48 min, and 9.71 mg/L respectively. Langmuir isotherm with R2= 0.9904 for Arsenate was the best graph for the experimental data. According to Langmuir isotherm model, the maximum amount of arsenate adsorption was 135.14mg/g. . The investigation of arsenate adsorption kinetics showed that arsenate adsorption follows the pseudo-second kinetics model. Conclusion: This research showed that the adsorption process is depended on pH. With increasing pH, the ability of amine groups in chitosan are decreased to protonation, caused to decrease the efficiency of arsenate removal at high pH.

  7. A New Adsorbent Composite Material Based on Metal Fiber Technology and Its Application in Adsorption Heat Exchangers

    Directory of Open Access Journals (Sweden)

    Ursula Wittstadt

    2015-08-01

    Full Text Available In order to achieve process intensification for adsorption chillers and heat pumps, a new composite material was developed based on sintered aluminum fibers from a melt-extraction process and a dense layer of silico-aluminophosphate (SAPO-34 on the fiber surfaces. The SAPO-34 layer was obtained through a partial support transformation (PST process. Preparation of a composite sample is described and its characteristic pore size distribution and heat conductivity are presented. Water adsorption data obtained under conditions of a large pressure jump are given. In the next step, preparation of the composite was scaled up to larger samples which were fixed on a small adsorption heat exchanger. Adsorption measurements on this heat exchanger element that confirm the achieved process intensification are presented. The specific cooling power for the adsorption step per volume of composite is found to exceed 500 kW/m3 under specified conditions.

  8. 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.

  9. Corrosion properties of plasma electrolytic oxidation coatings on an aluminium alloy – The effect of the PEO process stage

    Energy Technology Data Exchange (ETDEWEB)

    Dehnavi, Vahid, E-mail: vdehnavi@uwo.ca [Department of Chemical and Biochemical Engineering, University of Western Ontario, London, N6A 5B9 ON (Canada); Shoesmith, David W., E-mail: dwshoesm@uwo.ca [Surface Science Western, Department of Chemistry, University of Western Ontario, London, N6A 5B7 ON (Canada); Luan, Ben Li, E-mail: Ben.Luan@nrc-cnrc.gc.ca [National Research Council Canada, 800 Collip Circle, London, N6G4X8 ON (Canada); Department of Chemistry, University of Western Ontario, London, N6A 5B7 ON (Canada); Yari, Mehdi, E-mail: myari@uwo.ca [Department of Chemistry, University of Western Ontario, London, N6A 5B7 ON (Canada); Liu, Xing Yang, E-mail: XingYang.Liu@nrc-cnrc.gc.ca [National Research Council Canada, 800 Collip Circle, London, N6G4X8 ON (Canada); Rohani, Sohrab, E-mail: srohani@uwo.ca [Department of Chemical and Biochemical Engineering, University of Western Ontario, London, N6A 5B9 ON (Canada)

    2015-07-01

    Plasma electrolytic oxidation (PEO) coatings were grown on an aluminium alloy substrate using different processing parameters which enabled samples to be coated to different stages of the PEO process. Electrochemical impedance spectroscopy (EIS) and linear polarization resistance (LPR) techniques were employed to investigate the impedance properties of the resulting oxide coatings which will determine the corrosion performance of the coated alloy. Scanning electron microscopy was used to relate the morphology of the coatings with their corrosion performance. A direct relationship was found between the stage of the PEO process, which affects the microstructure of the coatings, and the corrosion performance. Coating thickness and phase composition did not have any measurable influence on coating corrosion performance. To some degree corrosion performance could be tailored by the processing parameters. - Highlights: • Corrosion performance of PEO coatings was found to be dependent on coating stage. • The PEO stage determined by the process parameters controlled coatings morphology. • Samples coated at the end of stage 3 demonstrated better corrosion properties. • Coating thickness and phase composition showed no influence on corrosion resistance.

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

    Science.gov (United States)

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

    2013-10-01

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

  11. 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.

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

    Science.gov (United States)

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

    2013-03-15

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

  13. Investigation of rare earth sealing of porous micro-arc oxidation coating formed on AZ91D magnesium alloy

    Institute of Scientific and Technical Information of China (English)

    M.Laleh; Farzad Kargar; A.Sabour Rouhaghdam

    2012-01-01

    Magnesium and its alloys have been used in many industries,but they are reactive and require protection against aggressive environments.In this study,oxide coatings were applied on AZ91D magnesium alloy using micro-arc oxidation (MAO) process.Then,in order to seal the pores of the MAO coatings,the samples were immersed in cerium bath for different times.The surface morphologies and compositions of the coatings were analyzed by scanning electron microscopy (SEM) and X-ray energy dispersive spectroscopy (EDS),respectively.The corrosion behavior of the coatings was investigated with electrochemical impedance spectroscopy (EIS) and potentiodynamic polarization tests in 3.5 wt.% NaCl solution.The amount of the porosity of the coating was measured by electrochemical method.It was found that the sealing treatments by immersion in cerium bath successfully sealed the pores of the MAO coatings.The results of the corrosion tests showed that the MAO coating which was sealed in Ce bath for 10 min enhanced the corrosion resistance of the substrate significantly.Furthermore,this coating had the lowest amount of the porosity among the coatings.

  14. Synthesis and electrochemical performance of ruthenium oxide-coated carbon nanofibers as anode materials for lithium secondary batteries

    Science.gov (United States)

    Hyun, Yura; Choi, Jin-Yeong; Park, Heai-Ku; Lee, Chang-Seop

    2016-12-01

    In this study, ruthenium oxide (RuO2) coated carbon nanofibers (CNFs) were synthesized and applied as anode materials of Li secondary batteries. The CNFs were grown on Ni foam via chemical vapor deposition (CVD) method after CNFs/Ni foam was put into the 0.01 M RuCl3 solution. The ruthenium oxide-coated CNFs/Ni foam was dried in a dryer at 80 °C. The morphologies, compositions, and crystal quality of RuO2/CNFs/Ni foam were characterized by SEM, EDS, XRD, Raman spectroscopy, and XPS. The electrochemical characteristics of RuO2/CNFs/Ni foam as anode of Li secondary batteries were investigated using three-electrode cell. The RuO2/CNFs/Ni foam was directly employed as a working electrode without any binder, and lithium foil was used as the counter and reference electrodes. LiClO4 (1 M) was employed as electrolyte and dissolved in a mixture of propylene carbonate (PC): ethylene carbonate (EC) in a 1:1 volume ratio. The galvanostatic charge/discharge cycling and cyclic voltammetry measurements were carried out at room temperature by using a battery tester. In particular, synthesized RuO2/CNFs/Ni foam showed the highest retention rate (47.4%). The initial capacity (494 mAh/g) was reduced to 234 mAh/g after 30 cycles.

  15. Effect of electrolyte components on the magnetic and magnetoresistive characteristics of Fe-containing plasma electrolytic oxide coatings on titanium

    Science.gov (United States)

    Rudnev, V. S.; Adigamova, M. V.; Tkachenko, I. A.; Sergienko, V. I.; Yanushkevich, K. I.; Aplesnin, S. S.; Lukiyanchuk, I. V.; Morozova, V. P.; Medkov, M. A.

    2017-03-01

    The effect replacing Na3PO4 with Na2HPO4 in aqueous phosphate-borate-tungstate electrolyte that additionally contains Fe2(C2O4)3 on the magnetic and magnetoresistive characteristics of oxide coating/ titanium composites formed by means of plasma electrolytic oxidation (PEO) is investigated. It is established that PEO coatings with ferromagnetic characteristics form on titanium in an electrolyte containing Na3PO4 (pH 11) upon adding iron(III) oxalate, while replacing Na3PO4 with Na2HPO4 and the respective drop in the pH of the base electrolyte down to 9.8 results in the formation of coatings with different magnetic characteristics. The correlation between changes in the values of the charge carriers' activation energy and the magnetic susceptibility is demonstrated for the latter. An increase in the electric resistance of coatings in a magnetic field is observed, and the type of the magnetic resistance temperature dependence is established.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    1999-01-01

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

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

    Science.gov (United States)

    Dai, Mingzhi; Vogt, Bryan D

    2012-12-01

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

  18. 壳聚糖/明胶微球吸附脱色剂的制备%Preparation of adsorbent with chitosan/gelatin composite microspheres

    Institute of Scientific and Technical Information of China (English)

    薛海燕; 贺宝元; 王学川

    2011-01-01

    Chitosan-gelatin composite microspheres, as dye wastewater adsorbent, are prepared by inverse suspension polymerization , uSing chitosan ( CS ) and gelatin as raw material, glutaraldehyde as cross-linking agent.The SEM ( scanning alectron microscope) micrographs show that the particle size of microspheres is uniform with 20 μm in diameter.The data of FTIR spectra indicate that the cross-linking between chitosan-gelatin and glutaraldehyde is occurred.The adsorption charactaristics of acid red 337 by chitosan-gelatin composite microshperes are investigated.The experimental results show that the maximum adsorption rate can reach 98% under dye concentration 0.5 g/L, composita microspheras concentration 0.5 g/L.The optimum absorption conditions of composite microspheres are pH 2 ~ 3 , adsorption at 30 ℃ for 100 min.%以壳聚糖和明胶为原料,戊二醛为交联剂,采用反相悬浮乳液聚合法制备壳聚糖/明胶微球,可作为染液废水吸附剂.扫描电镜显示,微球粒径均匀,平均约20 μm;红外光谱数据则证明壳聚糖、明胶与戊二醛之间发生了交联.复合微球对染液中酸性红337的吸附性能试验表明,当染料质量浓度0.5 g/L,复合微球质量浓度0.5 g/L时,吸附率可达到98%;复合微球吸附的最佳条件是:pH值2~3,吸附时间100 min,温度30℃.

  19. Chitosan-Iron Oxide Coated Graphene Oxide Nanocomposite Hydrogel: A Robust and Soft Antimicrobial Biofilm.

    Science.gov (United States)

    Konwar, Achyut; Kalita, Sanjeeb; Kotoky, Jibon; Chowdhury, Devasish

    2016-08-17

    We report a robust biofilm with antimicrobial properties fabricated from chitosan-iron oxide coated graphene oxide nanocomposite hydrogel. For the first time, the coprecipitation method was used for the successful synthesis of iron oxide coated graphene oxide (GIO) nanomaterial. After this, films were fabricated by the gel-casting technique aided by the self-healing ability of the chitosan hydrogel network system. Both the nanomaterial and the nanocomposite films were characterized by techniques such as scanning electron microscopy, FT-IR spectroscopy, X-ray diffraction, and vibrating sample magnetometry. Measurements of the thermodynamic stability and mechanical properties of the films indictaed a significant improvement in their thermal and mechanical properties. Moreover, the stress-strain profile indicated the tough nature of the nanocomposite hydrogel films. These improvements, therefore, indicated an effective interaction and good compatibility of the GIO nanomaterial with the chitosan hydrogel matrix. In addition, it was also possible to fabricate films with tunable surface properties such as hydrophobicity simply by varying the loading percentage of GIO nanomaterial in the hydrogel matrix. Fascinatingly, the chitosan-iron oxide coated graphene oxide nanocomposite hydrogel films displayed significant antimicrobial activities against both Gram-positive and Gram-negative bacterial strains, such as methicillin-resistant Staphylococcus aureus, Staphylococcus aureus, and Escherichia coli, and also against the opportunistic dermatophyte Candida albicans. The antimicrobial activities of the films were tested by agar diffusion assay and antimicrobial testing based on direct contact. A comparison of the antimicrobial activity of the chitosan-GIO nanocomposite hydrogel films with those of individual chitosan-graphene oxide and chitosan-iron oxide nanocomposite films demonstrated a higher antimicrobial activity for the former in both types of tests. In vitro hemolysis

  20. Adsorption of Th{sup 4+}, U{sup 6+}, Cd{sup 2+}, and Ni{sup 2+} from aqueous solution by a novel modified polyacrylonitrile composite nanofiber adsorbent prepared by electrospinning

    Energy Technology Data Exchange (ETDEWEB)

    Dastbaz, Abolfazl [Department of Chemical engineering, University of Tehran, Tehran (Iran, Islamic Republic of); Keshtkar, Ali Reza, E-mail: akeshtkar@aeoi.org.ir [Nuclear Fuel Cycle Research School, Nuclear Science and Technology Research Institute, Tehran (Iran, Islamic Republic of)

    2014-02-28

    In this study, SiO{sub 2} 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, SiO{sub 2} 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{sup −1} and the adsorbent affinity for metal ions was in order of Th{sup 4+} > U{sup 6+} > Cd{sup 2+} > Ni{sup 2+}. 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 Th{sup 4+}, U{sup 6+}, Cd{sup 2+}, and Ni{sup 2+} at 45 °C was 249.4, 193.1, 69.5 and 138.7 mg g{sup −1}, respectively. Besides, the calculated thermodynamic parameters showed an endothermic as well as chemical nature through the adsorption process.

  1. 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.

  2. 3 D-Cf/SiC复合材料抗高温氧化涂层结构设计与自愈合机理%Structure design and self-sealing mechanism of anti-high temperature oxidation coatings of 3 D-Cf/SiC composites

    Institute of Scientific and Technical Information of China (English)

    陈志彦; 向洁琼; 邹世钦

    2014-01-01

    为了提高3D-Cf/SiC 复合材料耐高温氧化性能,采用CVD和粉末烧结技术相结合依次在其表面制成 CVD-SiC 粘接层-自愈合功能层-CVD-SiC 耐冲蚀层等抗高温氧化涂层。运用 TG、SEM 和 TEM等手段研究了自愈合机理。结果表明,抗高温氧化涂层自愈合机理主要是 B4 C 和 MoSi2等氧化增重形成在高温下可流动的玻璃相,玻璃相充填材料裂纹和空隙有效地阻碍氧气渗透。因而3D-Cf/SiC复合材料具有较好的耐高温氧化性能。%In order to increase anti-high temperature oxidation properties of 3D-Cf/SiC composites,oxidation re-sistant coatings,including a chemical vapor deposition (CVD)SiC bonding layer,a self-sealing active layer and a CVD-SiC erosion resistant layer,were prepared on carbon fiber reinforced silicon carbide (3D-Cf/SiC)com-posites by CVD and powder sintering technology.TG,SEM and TEM were used to research self-sealing mecha-nism of the coating.The results show that the self-healing mechanism of the coating was mainly that flowing glass phases oxidized of B4 C and MoSi2 fill in material cracks and pores,and block off the passage of oxygen at high temperature.So 3D-Cf/SiC composites have good high temperature oxidation resistance properties.

  3. Synthesis of linear low-density polyethylene-g-poly (acrylic acid)-co-starch/organo-montmorillonite hydrogel composite as an adsorbent for removal of Pb(ΙΙ) from aqueous solutions.

    Science.gov (United States)

    Irani, Maryam; Ismail, Hanafi; Ahmad, Zulkifli; Fan, Maohong

    2015-01-01

    The purpose of this work is to remove Pb(II) from the aqueous solution using a type of hydrogel composite. A hydrogel composite consisting of waste linear low density polyethylene, acrylic acid, starch, and organo-montmorillonite was prepared through emulsion polymerization method. Fourier transform infrared spectroscopy (FTIR), Solid carbon nuclear magnetic resonance spectroscopy (CNMR)), silicon(-29) nuclear magnetic resonance spectroscopy (Si NMR)), and X-ray diffraction spectroscope ((XRD) were applied to characterize the hydrogel composite. The hydrogel composite was then employed as an adsorbent for the removal of Pb(II) from the aqueous solution. The Pb(II)-loaded hydrogel composite was characterized using Fourier transform infrared spectroscopy (FTIR)), scanning electron microscopy (SEM)), and X-ray photoelectron spectroscopy ((XPS)). From XPS results, it was found that the carboxyl and hydroxyl groups of the hydrogel composite participated in the removal of Pb(II). Kinetic studies indicated that the adsorption of Pb(II) followed the pseudo-second-order equation. It was also found that the Langmuir model described the adsorption isotherm better than the Freundlich isotherm. The maximum removal capacity of the hydrogel composite for Pb(II) ions was 430mg/g. Thus, the waste linear low-density polyethylene-g-poly (acrylic acid)-co-starch/organo-montmorillonite hydrogel composite could be a promising Pb(II) adsorbent.

  4. Synthesis of linear low-density polyethylene-g-poly (acrylic acid)-co-starch/organo-montmorillonite hydrogel composite as an adsorbent for removal of Pb(Ⅱ) from aqueous solutions

    Institute of Scientific and Technical Information of China (English)

    Maryam Irani; Hanafi Ismail; Zulkifli Ahmad; Maohong Fan

    2015-01-01

    The purpose of this work is to remove Pb(Ⅱ) from the aqueous solution using a type of hydrogel composite.A hydrogel composite consisting of waste linear low density polyethylene,acrylic acid,starch,and organo-montmorillonite was prepared through emulsion polymerization method.Fourier transform infrared spectroscopy (FTIR),Solid carbon nuclear magnetic resonance spectroscopy (CNMR)),silicon-29 nuclear magnetic resonance spectroscopy (Si NMR)),and X-ray diffraction spectroscope ((XRD) were applied to characterize the hydrogel composite.The hydrogel composite was then employed as an adsorbent for the removal of Pb(Ⅱ) from the aqueous solution.The Pb(Ⅱ)-loaded hydrogel composite was characterized using Fourier transform infrared spectroscopy (FTIR)),scanning electron microscopy (SEM)),and X-ray photoelectron spectroscopy ((XPS)).From XPS results,it was found that the carboxyl and hydroxyl groups of the hydrogel composite participated in the removal of Pb(Ⅱ).Kinetic studies indicated that the adsorption of Pb(Ⅱ)followed the pseudo-second-order equation.It was also found that the Langmuir model described the adsorption isotherm better than the Freundlich isotherm.The maximum removal capacity of the hydrogel composite for Pb(Ⅱ) ions was 430 mg/g.Thus,the waste linear low-density polyethylene-g-poly (acrylic acid)-co-starch/organo-montmorillonite hydrogel composite could be a promising Pb(Ⅱ) adsorbent.

  5. AM50镁合金表面含氧化锆的微弧氧化复合涂层的形成过程%Formation process of composite plasma electrolytic oxidation coating containing zirconium oxides on AM50 magnesium alloy

    Institute of Scientific and Technical Information of China (English)

    刘锋; 单大勇; 宋影伟; 韩恩厚

    2011-01-01

    The formation processes of a composite ceramic coating on AM50 magnesium alloy prepared by plasma electrolytic oxidation (PEO) in a K2ZrF6 electrolyte solution were studied by scanning electron microscope (SEM) and energy dispersive X-ray spectroscope (EDX). Electrochemical impedance spectroscopy (EIS) tests were used to study the variation of the corrosion resistance of the coating during the PEO treatment. The results show that the coating formed on Mg alloy is mainly composed of MgO and MgF2 when the applied voltage is lower than the sparking voltage, and zirconium oxides start to be deposited on Mg substrate after the potential exceeding the sparking voltage. The corrosion resistance of the coating increases with increasing the applied voltage.%采用扫描电镜(SEM)和电子衍射能谱(EDX)研究在含K2ZrF6的溶液中AM50镁合金表而复合微弧体氧化涂层的形成过程.采用电化学阻抗谱(EIS)研究在微弧体氧化制备膜层过程中膜层耐腐蚀性能的变化.结果表明:当电压小于起弧电压时,合金表面膜层的主要成分为MgO和MgF3;当施加电压超过起弧电压时,锆氧化物开始在合金表面沉积,且膜层的耐腐蚀性随着电压的升高而提高.

  6. 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.)

  7. 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.

  8. Tribological properties of solid lubricating film/microarc oxidation coating on Al alloys

    Institute of Scientific and Technical Information of China (English)

    LUO Zhuang-zi; ZHANG Zhao-zhu; LIU Wei-min; TIAN Jun

    2005-01-01

    A process for preparation of solid lubricating films on micro-arc oxidation(MAO) coating was introduced to provide self-lubricating and wear-resistant multilayer coatings for aluminum alloys. The friction and wear behavior of various burnished and bonded solid lubricating films on the as-deposited and polished micro-arc oxidation coatings sliding against steel and ceramic counterparts was evaluated with a Timken tester and a reciprocating friction and wear tester, respectively. The burnished and bonded solid lubricating films on the polished micro-arc oxidation coatings are superior to the as-deposited ones in terms of the wear resistant behavior, because they lead to strengthened interfacial adhesion between the soft lubricating top-film and the hard polished MAO sub-coating, which helps increase the wear resistance of the solid lubricating film on multilayer coating. Thus the multilayer coatings are potential candidates as self-lubricating and wear-resistant coatings for Al alloy parts in engineering applications.

  9. Interface control of atomic layer deposited oxide coatings by filtered cathodic arc deposited sublayers for improved corrosion protection

    Energy Technology Data Exchange (ETDEWEB)

    Härkönen, Emma, E-mail: emma.harkonen@helsinki.fi [Laboratory of Inorganic Chemistry, University of Helsinki, P.O. Box 55, FIN-00014 Helsinki (Finland); Tervakangas, Sanna; Kolehmainen, Jukka [DIARC-Technology Inc., Espoo (Finland); Díaz, Belén; Światowska, Jolanta; Maurice, Vincent; Seyeux, Antoine; Marcus, Philippe [Laboratoire de Physico-Chimie des Surfaces, CNRS (UMR 7075) – Chimie ParisTech (ENSCP), F-75005 Paris (France); Fenker, Martin [FEM Research Institute, Precious Metals and Metals Chemistry, D-73525 Schwäbisch Gmünd (Germany); Tóth, Lajos; Radnóczi, György [Research Centre for Natural Sciences HAS, (MTA TKK), Budapest (Hungary); Ritala, Mikko [Laboratory of Inorganic Chemistry, University of Helsinki, P.O. Box 55, FIN-00014 Helsinki (Finland)

    2014-10-15

    Sublayers grown with filtered cathodic arc deposition (FCAD) were added under atomic layer deposited (ALD) oxide coatings for interface control and improved corrosion protection of low alloy steel. The FCAD sublayer was either Ta:O or Cr:O–Ta:O nanolaminate, and the ALD layer was Al{sub 2}O{sub 3}–Ta{sub 2}O{sub 5} nanolaminate, Al{sub x}Ta{sub y}O{sub z} mixture or graded mixture. The total thicknesses of the FCAD/ALD duplex coatings were between 65 and 120 nm. Thorough analysis of the coatings was conducted to gain insight into the influence of the FCAD sublayer on the overall coating performance. Similar characteristics as with single FCAD and ALD coatings on steel were found in the morphology and composition of the duplex coatings. However, the FCAD process allowed better control of the interface with the steel by reducing the native oxide and preventing its regrowth during the initial stages of the ALD process. Residual hydrocarbon impurities were buried in the interface between the FCAD layer and steel. This enabled growth of ALD layers with improved electrochemical sealing properties, inhibiting the development of localized corrosion by pitting during immersion in acidic NaCl and enhancing durability in neutral salt spray testing. - Highlights: • Corrosion protection properties of ALD coatings were improved by FCAD sublayers. • The FCAD sublayer enabled control of the coating-substrate interface. • The duplex coatings offered improved sealing properties and durability in NSS. • The protective properties were maintained during immersion in a corrosive solution. • The improvements were due to a more ideal ALD growth on the homogeneous FCAD oxide.

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

    Energy Technology Data Exchange (ETDEWEB)

    Polat, Aytekin, E-mail: apolat@nigde.edu.t [Department of Mechanical Engineering, Nigde University, Nigde 51100 (Turkey); Makaraci, Murat [Department of Mechanical Engineering, Kocaeli University, Kocaeli (Turkey); Usta, Metin [Department of Materials Science and Engineering, Gebze Institute of Technology, Kocaeli (Turkey)

    2010-08-20

    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 (R{sub a}) and critical load (L{sub c}) corresponding to adhesive failure of the coatings were increased simultaneously from 74 to 144 {mu}m, and 4.4 to 6.58 {mu}m, and 127.76 to 198.54 N, respectively. At the same time, the phase structure and composition of the coatings also varied by the participation of silicate ions in the reactions and their incorporation into the coating structure. Moreover, it was observed that the coating formed in the low sodium silicate concentration (4 g/l) had higher surface hardness (2020 HV) and improved wear resistance than the one (1800 HV) formed in the high sodium silicate concentration (8 g/l). The coatings produced in three different electrolytic solutions provided an excellent wear resistance and a load carrying capacity compared to the uncoated aluminum alloy.

  11. Molecularly Imprinted Filtering Adsorbents for Odor Sensing

    Directory of Open Access Journals (Sweden)

    Sho Shinohara

    2016-11-01

    Full Text Available Versatile odor sensors that can discriminate among huge numbers of environmental odorants are desired in many fields, including robotics, environmental monitoring, and food production. However, odor sensors comparable to an animal’s nose have not yet been developed. An animal’s olfactory system recognizes odor clusters with specific molecular properties and uses this combinatorial information in odor discrimination. This suggests that measurement and clustering of odor molecular properties (e.g., polarity, size using an artificial sensor is a promising approach to odor sensing. Here, adsorbents composed of composite materials with molecular recognition properties were developed for odor sensing. The selectivity of the sensor depends on the adsorbent materials, so specific polymeric materials with particular solubility parameters were chosen to adsorb odorants with various properties. The adsorption properties of the adsorbents could be modified by mixing adsorbent materials. Moreover, a novel molecularly imprinted filtering adsorbent (MIFA, composed of an adsorbent substrate covered with a molecularly imprinted polymer (MIP layer, was developed to improve the odor molecular recognition ability. The combination of the adsorbent and MIP layer provided a higher specificity toward target molecules. The MIFA thus provides a useful technique for the design and control of adsorbents with adsorption properties specific to particular odor molecules.

  12. Preparation of magnetic graphene/mesoporous silica composites with phenyl-functionalized pore-walls as the restricted access matrix solid phase extraction adsorbent for the rapid extraction of parabens from water-based skin toners.

    Science.gov (United States)

    Feng, Jianan; He, Xinying; Liu, Xiaodan; Sun, Xueni; Li, Yan

    2016-09-23

    In this work, phenyl-functionalized magnetic graphene/mesoporous silica composites (MG-mSiO2-Ph) were prepared and applied as restricted access matrix solid phase extraction (RAM-SPE) adsorbents to determine the parabens in commercially available retail cosmetics. MG-mSiO2-Ph composites were synthesized by a surfactant-mediated co-condensation reaction in which mesoporous silica with phenyl-functionalized pore-walls was coated on a magnetic graphene sheet. The obtained nano-composites were proven to be of sufficient quality for an ideal RAM-SPE adsorbent with a large specific surface area of 369m(2)g(-1), uniform mesopores of 2.8nm, and special phenyl-functionalized pore-walls. Parabens, such as methyl paraben, ethyl paraben and propyl paraben, were extracted from water-based skin toners using one step of the RAM-SPE and were then analysed by a HPLC-DAD system. The SPE conditions were optimized by studying the parameters, such as the adsorbent amount, elution solvent type, adsorption time and desorption time, that influence the extraction efficiency. For each analyte, there were good linearities of approximately 0.10-120μgmL(-1) with determination coefficients (R(2))>0.995. The sensitivity was as low as 0.01-0.025μgmL(-1) for the LOD, and the percent recoveries were 98.37-105.84%. The intra-day and inter-day RSDs were 1.44-6.11% (n=6) and 3.12-11.70% (n=6), respectively. The results indicated that this method with novel RAM-SPE adsorbents is sensitive and convenient. The results also offered an attractive alternative for the extraction and determination of paraben preservatives in a complex matrix, such as cosmetics.

  13. 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.

  14. Enhanced Rate Capability of Oxide Coated Lithium Titanate within Extended Voltage Ranges

    Directory of Open Access Journals (Sweden)

    Dongjoon eAhn

    2015-06-01

    Full Text Available Lithium titanate (Li4Ti5O12 or LTO is a promising negative electrode material of high power lithium-ion batteries, due to its superior rate capability and excellent capacity retention. However, the specific capacity of LTO is less than one half of that of graphite electrode. In this work, we applied ultrathin oxide coating on LTO by the atomic layer deposition (ALD technique, aiming for increasing the energy density by extending the cell voltage window and specific capacity of LTO. We demonstrated that a few nanometer thick Al2O3 coating can suppress the mechanical distortion of LTO cycled at low potential, which enable the higher specific capacity and excellent capacity retentio. Furthermore, the surface coating can facilitate the charge transfer, leading to significantly improved rate capabilities, comparing with the uncoated LTO.

  15. 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

  16. Improving the scratch resistance of sol-gel metal oxide coatings cured at 250 C through use of thermogenerated amines

    NARCIS (Netherlands)

    Langanke, J.; Arfsten, N.; Buskens, P.; Habets, R.; Klankermayer, J.; Leitner, W.

    2013-01-01

    Scratch resistant sol-gel metal oxide coatings typically require a thermal post-treatment step (curing process) at temperatures between 400 and 700 C. In this report, we demonstrate that the in situ generation of amines within sol-gel films facilitates the preparation of scratch resistant metal oxid

  17. Reduction of ripening time of full-scale manganese removal filters with manganese oxide-coated media

    NARCIS (Netherlands)

    Bruins, J.H.; Petrusevski, B.; Slokar, Y.M.; Huysman, K.; Joris, K.; Kruithof, J.C.; Kennedy, M.D.

    2015-01-01

    Effective manganese removal by conventional aeration-filtration with virgin filter media requires a long ripening time. The aim of this study was to assess the potential of manganese oxide-coated media to shorten the ripening time of filters with virgin media, under practical conditions. A full scal

  18. Modeling adsorption: Investigating adsorbate and adsorbent properties

    Science.gov (United States)

    Webster, Charles Edwin

    1999-12-01

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

  19. Hydrophobic Porous Material Adsorbs Small Organic Molecules

    Science.gov (United States)

    Sharma, Pramod K.; Hickey, Gregory S.

    1994-01-01

    Composite molecular-sieve material has pore structure designed specifically for preferential adsorption of organic molecules for sizes ranging from 3 to 6 angstrom. Design based on principle that contaminant molecules become strongly bound to surface of adsorbent when size of contaminant molecules is nearly same as that of pores in adsorbent. Material used to remove small organic contaminant molecules from vacuum systems or from enclosed gaseous environments like closed-loop life-support systems.

  20. 电解铜箔用涂层钛阳极表面结垢的去除%Descaling of oxide-coated titanium anode for manufacturing of electrolytic copper foils

    Institute of Scientific and Technical Information of China (English)

    徐海清; 胡耀红; 陈力格; 秦足足; 廖磊华; 张招贤

    2015-01-01

    采用X射线衍射(XRD)、X射线荧光光谱分析(XRF)测试了失效电解铜箔用钛阳极表面结垢成分,考察了BH−阳极除垢剂对电解铜箔用钛阳极表面结垢的去除效果,通过循环伏安曲线、极化曲线、强化寿命测试分析了 BH−阳极除垢剂对钛阳极电催化活性的影响,给出了电解铜箔用钛阳极在应用过程中的维护措施。结果表明,BH−阳极除垢剂可以有效去除结垢而不会破坏钛阳极表面的贵金属涂层,有利于延长钛阳极的寿命。%The composition of scale formed on surface of failure titanium anode used for manufacturing of electrolytic copper foils was examined by X-ray diffraction (XRD) and X-ray fluorescence analysis (XRF). The effectiveness of BH anode descaling agent on the oxide-titanium anode used for electrolytic copper foils was studied and its influence on electrocatalytic activity of the anode was analyzed through cyclic voltammetry, polarization curve measurement, and accelerated service life test. The maintenance methods for oxide-coated titanium anode during the manufacturing of electrolytic copper foils were presented. The results indicated that the BH anode descaling agent removes the scales effectively, and has no damage to the precious metal oxide coating, extending the service life of the oxide-coated titanium anode.

  1. 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.

  2. Thermal Conductivity of Epoxy Resin Reinforced with Magnesium Oxide Coated Multiwalled Carbon Nanotubes

    Directory of Open Access Journals (Sweden)

    Fei-Peng Du

    2013-01-01

    Full Text Available Magnesium oxide coated multiwalled carbon nanotubes (MgO@MWNT were fabricated and dispersed into epoxy matrix. The microstructures of MgO@MWNT and epoxy/MgO@MWNT nanocomposites were characterized by TEM and SEM. Electrical resistivity and thermal conductivity of epoxy nanocomposites were investigated with high resistance meter and thermal conductivity meter, respectively. MgO@MWNT has core-shell structure with MgO as shell and nanotube as core, and the thickness of MgO shell is ca. 15 nm. MgO@MWNT has been dispersed well in the epoxy matrix. MgO@MWNT loaded epoxy nanocomposites still retain electrical insulation inspite of the filler content increase. However, thermal conductivity of epoxy was increased with the MgO@MWNT content increasing. When MgO@MWNT content reached 2.0 wt.%, thermal conductivity was increased by 89% compared to neat epoxy, higher than that of unmodified MWNT nanocomposites with the same loading content.

  3. Effect of Negatively Charged Ions on the Formation of Microarc Oxidation Coating on 2024 Aluminium Alloy

    Institute of Scientific and Technical Information of China (English)

    Wei Yang; Bailing Jiang; Aiying Wang; Huiying Shi

    2012-01-01

    The present study deals with the effect of negatively charged ions on the ceramic coating formation on 2024 aluminium alloy during microarc oxidation (MAO) process. On the basis of the experimental results, two steps (the formation of an incipient film without arc presence and the growth of a ceramic coating with arc discharge) of MAO process have been observed. For comparison, four different negatively charged ions studied. It is proved that negatively charged ions strongly participated in the formation of an incipient film with high impedance value at the first step. The growth of ceramic coating depends on the combination between AI of the substrate and O from the electrolyte, and the negatively charged ions are little consumed. As an anodic oxide coating is prepared on the sample surface instead of the incipient film, the first step occurs easily and the growth of ceramic coating is accelerated. Furthermore, the mechanism of negatively charged ions in the formation of the MAO coating has been proposed.

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

    Energy Technology Data Exchange (ETDEWEB)

    1992-08-01

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

  5. Effects of oxide coating on the growth of single grain YBCO bulk superconductors

    Energy Technology Data Exchange (ETDEWEB)

    Park, S.D.; Jun, B.-H. [Neutron Science Division, Korea Atomic Energy Research Institute (KAERI), Daejeon 305-353 (Korea, Republic of); Park, B.J.; Jung, S.Y. [Superconductivity and Applications Group, Korea Electric Power Research Institute (KEPRI), Daejeon 305-380 (Korea, Republic of); Seong, B.S. [Neutron Science Division, Korea Atomic Energy Research Institute (KAERI), Daejeon 305-353 (Korea, Republic of); Kim, C.-J., E-mail: cjkim2@kaeri.re.k [Neutron Science Division, Korea Atomic Energy Research Institute (KAERI), Daejeon 305-353 (Korea, Republic of)

    2009-10-15

    Surface oxide coating and bottom inserting of oxide plates have been conducted to top seeded melt growth (TSMG) processed YBa{sub 2}Cu{sub 3}O{sub 7-y} (Y123) bulk superconductors with an aim of controlling the Y123 nucleation and growth. The coating medium for surfaces was Yb{sub 2}O{sub 3} solution and the bottom inserts were Yb{sub 2}O{sub 3}/Y{sub 2}O{sub 3} powder compact. Many vertical cracks were found to develop at the compact/insert interfaces when an Yb{sub 2}O{sub 3} insert was used, but the crack evolution was greatly reduced when a (Yb{sub 2}O{sub 3} + Y{sub 2}O{sub 3}) insert was used. The formation of the vertical cracks is ascribed to the difference in thermal expansion between the YBCO compact and bottom insert. Presence of vertical cracks was found to be crucial to the trapped magnetic field and levitation forces of single grain YBCO bulk superconductors. The Y123 nucleation and growth in TSMG-processed YBCO bulk superconductors were successfully controlled by conducting surface coating and bottom plating using a (Yb{sub 2}O{sub 3} + Y{sub 2}O{sub 3}) insert and as a result, the levitation properties were much enhanced.

  6. Role of Additives in Composite PEI/Oxide CO₂ Adsorbents: Enhancement in the Amine Efficiency of Supported PEI by PEG in CO₂ Capture from Simulated Ambient Air.

    Science.gov (United States)

    Sakwa-Novak, Miles A; Tan, Shuai; Jones, Christopher W

    2015-11-11

    Supported amines are promising candidate adsorbents for the removal of CO2 from flue gases and directly from ambient air. The incorporation of additives into polymeric amines such as poly(ethylenimine) (PEI) supported on mesoporous oxides is an effective strategy to improve the performance of the materials. Here, several practical aspects of this strategy are addressed with regards to direct air capture. The influence of three additives (CTAB, PEG200, PEG1000) was systematically explored under dry simulated air capture conditions (400 ppm of CO2, 30 °C). With SBA-15 as a model support for poly(ethylenimine) (PEI), the nature of the additive induced heterogeneities in the deposition of organic on the interior and exterior of the particles, an important consideration for future scale up to practical systems. The PEG200 additive increased the observed thermodynamic performance (∼60% increase in amine efficiency) of the adsorbents regardless of the PEI content, while the other molecules had less positive effects. A threshold PEG200/PEI value was identified at which the diffusional limitations of CO2 within the materials were nearly eliminated. The threshold PEG/PEI ratio may have physical origin in the interactions between PEI and PEG, as the optimal ratio corresponded to nearly equimolar OH/reactive (1°, 2°) amine ratios. The strategy is shown to be robust to the characteristics of the host support, as PEG200 improved the amine efficiency of PEI when supported on two varieties of mesoporous γ-alumina with PEI.

  7. UV protective zinc oxide coating for biaxially oriented polypropylene packaging film by atomic layer deposition

    Energy Technology Data Exchange (ETDEWEB)

    Lahtinen, Kimmo, E-mail: kimmo.lahtinen@lut.fi [ASTRaL, Lappeenranta University of Technology, Sammonkatu 12, FI-50130 Mikkeli (Finland); Kääriäinen, Tommi, E-mail: tommi.kaariainen@colorado.edu [ASTRaL, Lappeenranta University of Technology, Sammonkatu 12, FI-50130 Mikkeli (Finland); Johansson, Petri, E-mail: petri.johansson@tut.fi [Paper Converting and Packaging Technology, Tampere University of Technology, P.O.Box 589, FI-33101 Tampere (Finland); Kotkamo, Sami, E-mail: sami.kotkamo@tut.fi [Paper Converting and Packaging Technology, Tampere University of Technology, P.O.Box 589, FI-33101 Tampere (Finland); Maydannik, Philipp, E-mail: philipp.maydannik@lut.fi [ASTRaL, Lappeenranta University of Technology, Sammonkatu 12, FI-50130 Mikkeli (Finland); Seppänen, Tarja, E-mail: tarja.seppanen@lut.fi [ASTRaL, Lappeenranta University of Technology, Sammonkatu 12, FI-50130 Mikkeli (Finland); Kuusipalo, Jurkka, E-mail: jurkka.kuusipalo@tut.fi [Paper Converting and Packaging Technology, Tampere University of Technology, P.O.Box 589, FI-33101 Tampere (Finland); Cameron, David C., E-mail: david.cameron@miktech.fi [ASTRaL, Lappeenranta University of Technology, Sammonkatu 12, FI-50130 Mikkeli (Finland)

    2014-11-03

    Biaxially oriented polypropylene (BOPP) packaging film was coated with zinc oxide (ZnO) coatings by atomic layer deposition (ALD) in order to protect the film from UV degradation. The coatings were made at a process temperature of 100 °C using diethylzinc and water as zinc and oxygen precursors, respectively. The UV protective properties of the coatings were tested by using UV–VIS and infrared spectrometry, differential scanning calorimetry (DSC) and a mechanical strength tester, which characterised the tensile and elastic properties of the film. The results obtained with 36 and 67 nm ZnO coatings showed that the ZnO UV protective layer is able to provide a significant decrease in photodegradation of the BOPP film under UV exposure. While the uncoated BOPP film suffered a complete degradation after a 4-week UV exposure, the 67 nm ZnO coated BOPP film was able to preserve half of its original tensile strength and 1/3 of its elongation at break after a 6-week exposure period. The infrared analysis and DSC measurements further proved the UV protection of the ZnO coatings. The results show that a nanometre scale ZnO coating deposited by ALD is a promising option when a transparent UV protection layer is sought for polymer substrates. - Highlights: • Atomic layer deposited zinc oxide coatings were used as UV protection layers. • Biaxially oriented polypropylene (BOPP) film was well protected against UV light. • Formation of UV degradation products in BOPP was significantly reduced. • Mechanical properties of the UV exposed BOPP film were significantly improved.

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

    Science.gov (United States)

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

    2007-04-01

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

  9. Measurements of Total Hemispherical Emissivity of Several Stably Oxidized Metals and Some Refractory Oxide Coatings

    Science.gov (United States)

    Wade, William R.

    1959-01-01

    A description of the apparatus and methods used for obtaining total hemispherical emissivity is presented, and data for several stably oxidized metals are included. The metals which were tested included type 347 stainless steel, tungsten, and Haynes alloys B, C, X, and 25. No values of emissivity were obtained for tungsten or Haynes alloy B because of the nature of the oxides produced. The refractory oxide coatings tested were flame-sprayed alumina and zirconia. The results of the investigation indicate that strongly adherent, oxidized surfaces of a high stable emissivity can be produced on type 347 stainless steel for which the total hemispherical emissivity varied from 0.87 to 0.91 for temperatures from 600 F to 2,000 F. For this same temperature range, the Haynes alloys tested showed values of total hemispherical emissivity from 0.90 to 0.96 for alloy C, from 0.85 to 0.88 for alloy X, and from 0.85 to 0.89 for alloy 25. Haynes alloy B and tungsten formed nonadherent oxides at elevated temperatures and, therefore, stable emissivities were not obtained. The results obtained for the flame-sprayed ceramics (alumina and zirconia) showed considerably higher values of total emissivity than those measured for coatings applied by other methods. Emissivity values ranging from 0.69 to 0.44 for aluminum oxide and from 0.62 to 0.44 for zirconium oxide were measured for temperatures from 800 F to 2,000 F.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2009-11-02

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

  11. 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.

  12. 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.

  13. Effects of Al2O3 Nano-Particles on Corrosion Performance of Plasma Electrolytic Oxidation Coatings Formed on 6061 Aluminum Alloy

    Science.gov (United States)

    Vakili-Azghandi, Mojtaba; Fattah-alhosseini, Arash; Keshavarz, Mohsen K.

    2016-12-01

    Corrosion resistance improvement of plasma electrolyte oxidation coatings on 6061 aluminum alloy in silicate electrolyte containing Al2O3 nano-particles was studied, with particular emphasis on the microstructure, coating growth, and corrosion behavior in 3.5 wt.% NaCl solution. The microstructure of coatings, their thickness, and phase composition were characterized using scanning electron microscopy and x-ray diffraction. All characterization data showed that the maximum coating thickness and lowest amount of porosity were obtained in a low concentration of KOH, a high concentration of Na2SiO3, and moderate concentration of Al2O3 nano-particles in the electrolyte. This combination describes the optimum plasma electrolytic oxidation electrolyte, which has the best conductivity and oxidizing state, as well as the highest incorporation of electrolyte components in the coating growth process. On the other hand, incorporation and co-deposition of Al2O3 nano-particles were more pronounced than SiO3 2- ions in some level of molar concentration, which is due to the higher impact of electron discharge force on the adsorption of Al2O3 nano-particles. The electrochemical results showed that the best protective behavior was obtained in the sample having a coat with the lowest porosity and highest thickness.

  14. Effect of fulvic acid on adsorptive removal of Cr(VI) and As(V) from groundwater by iron oxide-based adsorbents

    KAUST Repository

    Uwamariya, V.

    2015-05-15

    Abstract Natural contamination has become a challenging problem in drinking water production due to metal contamination of groundwater throughout the world, and arsenic and chromium are well-known toxic elements. In this study, iron oxide-coated sand (IOCS) and granular ferric hydroxide (GFH) were used to study the effects of fulvic acid (FA) on the adsorptive removal of Cr(VI) and As(V) from synthetic groundwater. IOCS and GFH were characterized by SEM/EDS, and experiments were performed at different pH levels (6, 7, and 8). The surface of IOCS and GFH showed a high content of Fe and O (75 and 60 % of the atomic composition, respectively), suggesting that they can highly effectively adsorb Cr(VI) and As(V). Adsorption tests with the simultaneous presence of As(V) and FA, on the one hand, and Cr(VI) with FA, on the other hand, revealed that the role of FA on chromate and arsenate adsorption was insignificant at almost all pH values investigated with both adsorbents. A small influence as a result of FA was only observed for the removal of As(V) by IOCS at pH 6 with a decrease of 13 and 23 % when 2 and 5 mg/l were added to the synthetic water, respectively. It was also found that organic matter (OM) was leached from the IOCS during batch adsorption experiments. The use of FEEM revealed that humic-like, fulvic-like, and protein-like organic matter fractions are present on the IOCS surface. © 2015 Springer International Publishing Switzerland.

  15. 低温吸湿复合吸附剂的制备及吸湿性能%Preparation and dehumidification performance of composite adsorbent for low-temperature desiccants

    Institute of Scientific and Technical Information of China (English)

    赖艳华; 吴涛; 赵琳妍; 董震; 郝宗华; 陈常念; 吕明新

    2015-01-01

    针对冷库结霜严重制约其经济性的问题,化学固体吸附除湿防霜技术逐渐得到重视.本文将对水吸附能力较强的金属卤化物与容易定型且传热传质性能较好的分子筛相结合,制成复合吸附剂,建立了低温情况下吸附材料的吸湿性能测试系统,并进行了大量测试,给出了多种材料在?5℃、?10℃、?15℃下的吸湿量及吸湿速率变化,实验结果表明复合吸附剂的吸附性能与单纯的分子筛相比有了明显的改善,13X型分子筛浸渍浓度20%的NaBr溶液所得试样吸湿量和吸湿速率性能优越,复合过程中损失较少,成本低,可作为复合吸附剂应用于冷库除湿系统中.%Cold storage frost severely restricted its economy, to solve this problem, chemical adsorption dehumidification frost prevention technology has been paid great attention. Some kind of composite adsorbents have been made comparing metal halide which has great water adsorption capacity with molecular sieve, which has good heat and mass transfer properity, and is easy to shape. Moisture adsorption performance testing system has been constructed suitable for material under low temperature. A great many of tests have been made. The moisture adsorption capacity and rate of a variety of materials in?5℃,?10℃,?15℃ have been given. It is shown that the adsorption performance of compound adsorbent was obviously improved compared with pure molecular sieve. 13X molecular sieve dipping solution concentration 20% of NaBr had better amount of moisture adsorption and rate, less loss in the process of composition, low cost, which could be used in cold storage dehumidification system as a composite adsorbent.

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

    Science.gov (United States)

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

    2011-08-01

    Hard coatings for articulating surfaces of total joint replacements may improve the overall wear resistance. However, any coating approach must take account of changes in corrosion behavior. This preliminary assessment analyzes the corrosion kinetics, impedance and mechanical-electrochemical stability of 100 μm thick plasma sprayed chromium oxide (Cr₂O₃) coatings on bearing surfaces in comparison to the native alloy oxide films on Co-Cr-Mo and Ti-6Al-6V. Cyclic potentiodynamic polarization, electrochemical impedance spectroscopy, and mechanical abrasion under potentiostatic conditions were performed on coated and substrate surfaces in physiological saline. SEM analysis characterized the coating morphology. The results showed that the corrosion current density values of chromium oxide coatings (0.4-1.2 μA/cm²) were of the same order of magnitude as Ti-6Al-4V alloy. Mechanical abrasion did not increase corrosion rates of chromium oxide coatings but did for uncoated Co-Cr-Mo and Ti-6Al-4V. The impedance response of chromium oxide coatings was very different than Co-Cr-Mo and Ti-6Al-4V native oxides characterized by a defected coating model. More of a frequency-independent purely resistive response was seen in mid-frequency range for the coatings (CPE(coat) : 40-280 nF/cm² (rad/s)(1-α) , α: 0.67-0.83) whereas a more capacitive character is seen for Co-Cr-Mo and Ti-6Al-4V (CPE(ox) around 20 μF/cm² (rad/s)(1-α) , α around 0.9). Pores, interparticle gaps and incomplete fusion typical for thermal spray coatings were present in these oxides which could have influenced corrosion resistance. The coating microstructure could have allowed some fluid penetration. Overall, these coatings appear to have suitable corrosion properties for wear surfaces.

  17. Experimental Study of the Micro-Arc Oxide Coating Effect on Thermal Properties of an Aluminium Alloy Piston Head

    Directory of Open Access Journals (Sweden)

    N.Yu. Dudareva

    2015-09-01

    Full Text Available The purpose of the present study is to investigate the influence of differently sized microarc oxidation coatings, applied to the bottom of pistons made with an Al-12Si-Mg-Cu-Ni alloy, on its thermal properties by simulating the operation of a real engine. This study is based on the premise that the alumina coating thickness affects the heat transfer and temperature distribution in the piston. The analysis of thermal properties of pistons and suggestions for the optimal thermal barrier coating thickness are presented.

  18. Nanostructure Pt Electrode Obtained via Self-assembly of Nanoparticles on Conductive Oxide-coated Glass Substrate

    Institute of Scientific and Technical Information of China (English)

    WANG, Wei-Bo(王维波); LUO, Zhen(罗臻); XIAO, Xu-Rui(肖绪瑞); LIN, Yuan(林原)

    2004-01-01

    Self-assembly of platinum nanoparticles were applied to fabrication of counter electrode for dye-sensitized solar cells on conductive oxide-coated glass substrate. The present Pt electrode exhibits high exchange current density of 220 mA/cm2, which is comparable to those prepared by electrodeposition, magnetron sputtering or thermal decomposition of platinum chloride. After analysis by transmission electron microscopy (TEM), atomic force microscopy (AFM) and X-ray photoelectron spectroscopy (XPS), it was found that the catalyst was structurally characterized as nanosized platinum metal clusters and was continuously arranged on electrode surface. The present nanostructure electrode had high electrocatalytic activity for the reduction of iodine in organic solution.

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

    DEFF Research Database (Denmark)

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

    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...

  20. 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.

  1. 铝合金微弧氧化膜白色斑点成因分析%Analysis of white spot formation on the micro-arc oxidation coating of aluminum alloy

    Institute of Scientific and Technical Information of China (English)

    王青; 裴舒; 白利红; 武海玲; 苗成

    2011-01-01

    When micro-arc oxidation coatings were formed on aluminum alloy in silicate system electrolyte, white spots often appear on the coating, and the quality and appearance of work piece will be impaired. The composition of the white spots was analyzed by EDS and XRD. It is found that the white spots is SiO2. Furthermore, the formation reason was analyzed.%用硅酸盐体系电解液进行铝合金微弧氧化时,氧化膜表面出现白色斑点状物,影响零件质量和外观,对这种白色斑点状物进行EDS和XRD成分测试,同时还对形成原因进行分析.结果表明,白色斑点状物是由SiO2聚集而成.

  2. Stripping Process of the Magnesium Alloy Micro-arc Oxidation Coating%镁合金微弧氧化膜层退除工艺

    Institute of Scientific and Technical Information of China (English)

    李锦妍; 郝建民; 陈永楠; 陈宏

    2015-01-01

    the formula-tion of the coating stripping solution, using the stripping rate and surface roughness and the judgment criteria. The role of each component in the coating stripping solution was analyzed. The relationship between the weight loss and time during the stripping process, and the relationship of coating thickness with corrosion rate and roughness were discussed. The optimized coating stripping solution was then used to strip the magnesium alloy micro-arc oxidation coating, and the macro- and microstructure of the surface was observed. Results The extreme difference of the chemical reagents on the stripping rate and surface roughness of the magnesi-um alloy substrate after stripping was in the order of Rnitrate acid>RKF>Rcitric acid>RSDBS>Rcor osion inhibitor , indicating that the concentration of nitrate acid had the biggest effect on the stripping rate and surface roughness, followed by the concentration of potassium fluo-ride, and the concentrations of citric acid, SDBS and corrosion inhibitor had the least effect. During the whole process, the weight loss and the time did not have a linear relationship. The weight loss and the stripping rate were high in the beginning and at the end of the process, while in the middle of the process the weight loss and the time had a linear relationship, with a stripping rate lower the initial stripping rate. There were no corrosion products on the surface of the magnesium alloy according to the XRD pattern. As shown by SEM, the pores in the layer after the second micro-arc oxidation treatment on magnesium alloy were compact and uni-form, which had no obvious difference with the coating after the first treatment. Conclusion The best composition of the stripping so-lution for of the magnesium alloy micro-arc oxidation coating was nitric acid 90 mL/L, citric acid 8 g/L, potassium fluoride 35 g/L, dodecyl benzene sulfonic acid sodium 5 g/L, and corrosion inhibitor 6. 5 g/L. This solution led to good stripping of the magnesium

  3. Amplified photoacoustic performance and enhanced photothermal stability of reduced graphene oxide coated gold nanorods for sensitive photoacoustic imaging.

    Science.gov (United States)

    Moon, Hyungwon; Kumar, Dinesh; Kim, Haemin; Sim, Changbeom; Chang, Jin-Ho; Kim, Jung-Mu; Kim, Hyuncheol; Lim, Dong-Kwon

    2015-03-24

    We report a strongly amplified photoacoustic (PA) performance of the new functional hybrid material composed of reduced graphene oxide and gold nanorods. Due to the excellent NIR light absorption properties of the reduced graphene oxide coated gold nanorods (r-GO-AuNRs) and highly efficient heat transfer process through the reduced graphene oxide layer, r-GO-AuNRs exhibit excellent photothermal stability and significantly higher photoacoustic amplitudes than those of bare-AuNRs, nonreduced graphene oxide coated AuNRs (GO-AuNRs), or silica-coated AuNR, as demonstrated in both in vitro and in vivo systems. The linear response of PA amplitude from reduced state controlled GO on AuNR indicates the critical role of GO for a strong photothermal effect of r-GO-AuNRs. Theoretical studies with finite-element-method lab-based simulation reveal that a 4 times higher magnitude of the enhanced electromagnetic field around r-GO-AuNRs can be generated compared with bare AuNRs or GO-AuNRs. Furthermore, the r-GO-AuNRs are expected to be a promising deep-tissue imaging probe because of extraordinarily high PA amplitudes in the 4-11 MHz operating frequency of an ultrasound transducer. Therefore, the r-GO-AuNRs can be a useful imaging probe for highly sensitive photoacoustic images and NIR sensitive therapeutics based on a strong photothermal effect.

  4. Size selective hydrophobic adsorbent for organic molecules

    Science.gov (United States)

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

    1997-01-01

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

  5. 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.

  6. 凹土-氯化钙复合吸附剂的制冷性能%Adsorption Refrigeration Characteristic of Attapulgite Based Calcium Chloride Composite Adsorbents

    Institute of Scientific and Technical Information of China (English)

    万意; 李全国; 芮正球; 崔群; 陈海军; 王海燕; 姚虎卿

    2012-01-01

    采用凹凸棒粘土和氯化钙为主要原料,用溶解-混合法制备了复合吸附剂;采用正压重量法测量了复合吸附剂对氨的吸附等温线;并测定了吸附剂-氨工质对的制冷特性.结果表明:吸附温度30℃下,复合吸附剂对氨的平衡吸附量为1.1 kg/kg,与氯化钙对氨的平衡吸附量相当.在装填密度为600kg/m3,吸附温度为30℃、蒸发压力为0.25MPa、解吸温度为300℃条件下,对氨的吸附量达到0.89~0.92kg/kg,循环吸附量为0.55~0.58kg/kg,是纯氯化钙的1.7倍:复合吸附剂-氨工质对制冷量可达761.84kJ/kg,比氯化钙-氨工质对提高了70%.而且,复合吸附剂具有良好的吸附解吸稳定性能.%The composite absorbent is mainly consisted of attapulgite and CaCI2as the resources, which were prepared by the dissolution-mixed method, and the content of attapulgite in composite absorbent is 10%. Adsorption isotherms of ammonia on absorbents were determined by positive gravimetric method. Adsorption-desorption cycle performance and cooling characteristics of composite absorbent -ammonia working pairs was evaluated by self-made adsorption-desorption measuring device. Experimental results show that the equilibrium capacity of ammonia on the composite absorbent is up to l.lkg/kg at 30℃, which is equal to that of CaCl2. The conditions of loading density 600kg/m3, adsorption temperature 30℃, ammonia evaporation pressure 0.25 MPa, desorption temperature 300℃, adsorption capacity of ammonia in the composite absorbent and its cyclic adsorption capacity is 0.89-0.92 kg/kg and 0.55~0.58 kg/kg, respectively, which is 1.7 times than that of CaCl2-ammonia working pairs. The cooling capacity is up to 761.84kJ/kg, which is increased by 70% compared to CaCl2/ ammonia. What's more, composite absorbent has excellent adsorption and desorption stability.

  7. Cost-effective reduced graphene oxide-coated polyurethane sponge as a highly efficient and reusable oil-absorbent.

    Science.gov (United States)

    Liu, Yue; Ma, Junkui; Wu, Tao; Wang, Xingrui; Huang, Guanbo; Liu, Yu; Qiu, Haixia; Li, Yi; Wang, Wei; Gao, Jianping

    2013-10-23

    Reduced graphene oxide coated polyurethane (rGPU) sponges were fabricated by a facile method. The structure and properties of these rGPU sponges were characterized by Fourier transform infrared spectroscopy, thermal gravimetric analysis, X-ray diffraction, and scanning electron microscopy. The rGPU sponges are hydrophobic and oleophilic and show extremely high absorption for organic liquids. For all the organic liquids tested, the absorption capacities were higher than 80 g g(-1) and 160 g g(-1) (the highest value) was achieved for chloroform. In addition, the absorption capacity of the rGPU sponge did not deteriorate after it was reused 50 times, so the rGPU sponge has excellent recyclability.

  8. Influence of Electrolytes on the Microstructure of Microarc Oxidation Coatings on Ti-6Al-4V Alloy

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    Dense ceramic oxide coatings of about 50 μm may be prepared on Ti-6Al-4V alloy surface by alternating-currentmicroarc oxidation in aluminate and silicate solutions, respectively. Their phase constituent and microstructure werecharacterized using X-ray diffraction (XRD) and scanning electron microscopy (SEM). The results show that theelectrolytic ions have incorporated into the interior of the coatings. The coating formed in aluminate solution iscomposed of the rutile TiO2 and TiAl2O5 phases rather than the rutile, anatase and amorphous SiO2 phases for thecoating formed in silicate solution. However, TiAl2O5 content in the outer layer of the two coatings is much higherthan in the inner layer. It is suggested that all these oxides may result from a rapid solidification of the moltencoating in the microarc discharge zone.

  9. 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.

  10. 陶瓷纤维基硅胶/分子筛复合吸附剂的实验研究%Experimental Research on Silical Gel/Molecular Sieve Composite Adsorbents With Ceramic Fiber Matrix

    Institute of Scientific and Technical Information of China (English)

    蒋赣; 方玉堂; 丁静

    2011-01-01

    采用浸渍法在基材上原位反应生成硅胶,以硅溶胶作为分子筛的分散剂、黏合剂制备出陶瓷纤维基硅胶/分子筛复合吸附剂,采用静态法测定了吸附剂纸片和块体的吸附量,并利用静态吸附床结构来模拟转轮的工作状态,结果表明:在不同湿度条件下,复合吸附剂具有较高的静态和动态吸附量。%Silica gel/molecular sieve composite adsorbents(CA)were prepared by impregnation reaction on the ceramic fiber sheet which silica sol was used as dispersant and adhesive.The static adsorption performance of CA sheet and monolithic was tested,and their dynamic adsorption performance was also measured by using adsorbent bed to simulate the dehumidifying process of rotary-type dehumidifier.The results of experiments showed that CA had excellent dehumidifying ability under different humidity condition.

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

    Science.gov (United States)

    Katsoyiannis, Ioannis A; Zouboulis, Anastasios I

    2002-12-01

    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 production of high amounts of toxic sludge can be avoided and it is considered as economically more efficient; whereas it has not yet been applied in full-scale treatment plants for low-level arsenic removal. The present experiments showed that both modified media were capable in removing arsenic from the aqueous stream, leading to residual concentration of this toxic metalloid element below 10 microg/L, which is the new maximum concentration limit set recently by the European Commission and imposed by the USEPA. Though, among the examined materials, polyHIPE was found to be more effective in the removal of arsenic, as far as it concerns the maximum sorptive capacity before the filtration bed reaches the respective breakthrough point.

  12. 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)

  13. Fabrication of ceramic oxide-coated SWNT composites by sol-gel process with a polymer glue

    Energy Technology Data Exchange (ETDEWEB)

    Zhang Cheng; Gao Lei; Chen Yongming, E-mail: ymchen@iccas.ac.cn [Institute of Chemistry, Chinese Academy of Sciences, Laboratory of Polymer Physics and Chemistry (China)

    2011-09-15

    The functional copolymer bearing alkoxysilyl and pyrene groups, poly[3-(triethoxysilyl)propyl methacrylate]-co-[(1-pyrene-methyl) methacrylate] (TEPM{sub 13}-co-PyMMA{sub 3}), was synthesized via atom transfer radical polymerization. Attributing the {pi}-{pi} interaction of pyrene units with the walls of single-walled carbon nanotubes (SWNTs), this polymer could disperse and exfoliate SWNTs in different solvents through physical interaction as demonstrated by TEM, UV/Vis absorption, and FT-IR analysis. The alkoxysilyl groups functionalized SWNTs were reacted with different inorganic precursors via sol-gel reaction, and, as a results, silica, titania, and alumina were coated onto the surface of SWNTs, respectively via copolymers as a molecular glue. The nanocomposites of ceramic oxides/SWNTs were characterized by SEM analysis. Dependent upon the feed, the thickness of inorganic coating can be tuned easily. This study supplies a facile and general way to coat SWNTs with ceramic oxides without deteriorating the properties of pristine SWNTs.

  14. 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

  15. Characteristics of grain growth of microarc oxidation coatings on pure titanium

    Institute of Scientific and Technical Information of China (English)

    Wang Jian-Bo; Wu Han-Hua; Li Quan-Jun; Li Zhe-Kui; Gu Guang-Rui; Lü Xian-Yi; Zheng Wei-Tao; Jin Zeng-Sun

    2005-01-01

    Grainy titania coatings are prepared by microarc oxidation on pure titanium (TA2) substrates in a Na2SiO3-NaF electrolytic solution. The coating thickness is measured by an optical microscope with a CCD camera. Scanning electron microscope (SEM) and x-ray diffraction (XRD) are employed to characterize the microstructure and phase composition of coatings. The results show that the coating thickness increases linearly as the treatment time increases.The coatings are mainly composed of anatase and rutile (TiO2). With the increase of treatment time, the predominant phase composition varies from anatase to rutile, which indicates that phase transformation of anatase into rutile occurs in the oxidizing process. Meanwhile, the size of grains existing on the coating surface increases and thus the surface becomes much coarser.

  16. Influence of Divalent Cations on Deformation and Rupture of Adsorbed Lipid Vesicles.

    Science.gov (United States)

    Dacic, Marija; Jackman, Joshua A; Yorulmaz, Saziye; Zhdanov, Vladimir P; Kasemo, Bengt; Cho, Nam-Joon

    2016-06-28

    The fate of adsorbed lipid vesicles on solid supports depends on numerous experimental parameters and typically results in the formation of a supported lipid bilayer (SLB) or an adsorbed vesicle layer. One of the poorly understood questions relates to how divalent cations appear to promote SLB formation in some cases. The complexity arises from the multiple ways in which divalent cations affect vesicle-substrate and vesicle-vesicle interactions as well as vesicle properties. These interactions are reflected, e.g., in the degree of deformation of adsorbed vesicles (if they do not rupture). It is, however, experimentally challenging to measure the extent of vesicle deformation in real-time. Herein, we investigated the effect of divalent cations (Mg(2+), Ca(2+), Sr(2+)) on the adsorption of zwitterionic 1,2-dioleoyl-sn-glycero-3-phosphocholine (DOPC) lipid vesicles onto silicon oxide- and titanium oxide-coated substrates. The vesicle adsorption process was tracked using the quartz crystal microbalance-dissipation (QCM-D) and localized surface plasmon resonance (LSPR) measurement techniques. On silicon oxide, vesicle adsorption led to SLB formation in all cases, while vesicles adsorbed but did not rupture on titanium oxide. It was identified that divalent cations promote increased deformation of adsorbed vesicles on both substrates and enhanced rupture on silicon oxide in the order Ca(2+) > Mg(2+) > Sr(2+). The influence of divalent cations on different factors in these systems is discussed, clarifying experimental observations on both substrates. Taken together, the findings in this work offer insight into how divalent cations modulate the interfacial science of supported membrane systems.

  17. Preparation of micro-arc oxidation coatings on magnesium alloy and its thermal shock resistance property

    Institute of Scientific and Technical Information of China (English)

    JIANG Zhaohua; ZENG Xiaobin; YAO Zhongping

    2006-01-01

    In the NaAlO2-Na2SiO3 compound system, the ceramic coatings were prepared on magnesium alloy by micro-arc oxidation. The morphology, phase composition, and thermal shock resistance of the ceramic coatings were studied by scanning electron microscope, X-ray diffraction and thermal shock tests, respectively. The results showed that the ceramic coating contains MgO, MgAl2O4, as well as a little amount of Mg2SiO4. The thickness of the ceramic coatings induced ceramic coating is the best. The hardness of the ceramic coating is up to 10 GPa or so.

  18. Iron oxide coating films in soda-lime glass by triboadhesion

    Energy Technology Data Exchange (ETDEWEB)

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

    2009-04-15

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

  19. Characterization of calcium containing plasma electrolytic oxidation coatings on AM50 magnesium alloy

    Energy Technology Data Exchange (ETDEWEB)

    Srinivasan, P. Bala, E-mail: bala.srinivasan@gkss.de [Institute of Materials Research, GKSS-Forschungszentrum Geesthacht GmbH, D-21502 Geesthacht (Germany); Liang, J.; Blawert, C.; Stoermer, M.; Dietzel, W. [Institute of Materials Research, GKSS-Forschungszentrum Geesthacht GmbH, D-21502 Geesthacht (Germany)

    2010-04-01

    An attempt was made to produce calcium containing plasma electrolytic oxidation (PEO) coatings on AM50 magnesium alloy using an alkaline electrolyte. This study was performed in three alkaline electrolytes containing calcium hydroxide and sodium phosphate with three different mass ratios viz., 1:2.5, 1:5 and 1:7.5. All the three coatings produced were found to contain Ca and P in appreciable amounts. The concentration of P was found to be higher in the coatings obtained in the electrolytes with higher concentration of phosphate ions. Even though all the three coatings were found to be constituted with magnesium oxide and magnesium phosphate phases, X-ray diffraction analyses revealed that the phase composition was influenced by the phosphate ion concentration/conductivity of the electrolyte. Further, the PEO coating obtained in the 1:7.5 ratio electrolyte was found to contain di-calcium phosphate (monetite) and calcium peroxide phases, which were absent in the other two coatings. Potentiodynamic polarization studies performed in 0.1 M NaCl solution showed that the coatings obtained from the 1:5 ratio electrolyte possessed a superior corrosion resistance, which is attributed to the combined effect of thickness, compactness and phase/chemical composition of this coating.

  20. Substrate-adsorbate coupling in CO-adsorbed copper

    CERN Document Server

    Lewis, S P; Lewis, Steven P.; Rappe, Andrew M.

    1996-01-01

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

  1. Methane Recovery from Gaseous Mixtures Using Carbonaceous Adsorbents

    Science.gov (United States)

    Buczek, Bronisław

    2016-06-01

    Methane recovery from gaseous mixtures has both economical and ecological aspect. Methane from different waste gases like mine gases, nitrogenated natural gases and biogases can be treated as local source for production electric and heat energy. Also occurs the problem of atmosphere pollution with methane that shows over 20 times more harmful environmental effect in comparison to carbon dioxide. One of the ways utilisation such gases is enrichment of methane in the PSA technique, which requires appropriate adsorbents. Active carbons and carbon molecular sieve produced by industry and obtained in laboratory scale were examined as adsorbent for methane recuperation. Porous structure of adsorbents was investigated using densimetry measurements and adsorption of argon at 77.5K. On the basis of adsorption data, the Dubinin-Radushkevich equation parameters, micropore volume (Wo) and characteristics of energy adsorption (Eo) as well as area micropores (Smi) and BET area (SBET) were determined. The usability of adsorbents in enrichment of the methane was evaluated in the test, which simulate the basic stages of PSA process: a) adsorbent degassing, b) pressure raise in column by feed gas, c) cocurrent desorption with analysis of out flowing gas. The composition of gas phase was accepted as the criterion of the suitability of adsorbent for methane separation from gaseous mixtures. The relationship between methane recovery from gas mixture and texture parameters of adsorbents was found.

  2. 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.

  3. Development of highly faceted reduced graphene oxide-coated copper oxide and copper nanoparticles on a copper foil surface

    Directory of Open Access Journals (Sweden)

    Rebeca Ortega-Amaya

    2016-07-01

    Full Text Available This work describes the formation of reduced graphene oxide-coated copper oxide and copper nanoparticles (rGO-Cu2ONPs, rGO-CuNPs on the surface of a copper foil supporting graphene oxide (GO at annealing temperatures of 200–1000 °C, under an Ar atmosphere. These hybrid nanostructures were developed from bare copper oxide nanoparticles which grew at an annealing temperature of 80 °C under nitrogen flux. The predominant phase as well as the particle size and shape strongly depend on the process temperature. Characterization with transmission electron microscopy and scanning electron microscopy indicates that Cu or Cu2O nanoparticles take rGO sheets from the rGO network to form core–shell Cu–rGO or Cu2O–rGO nanostructures. It is noted that such ones increase in size from 5 to 800 nm as the annealing temperature increases in the 200–1000 °C range. At 1000 °C, Cu nanoparticles develop a highly faceted morphology, displaying arm-like carbon nanorods that originate from different facets of the copper crystal structure.

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

    Directory of Open Access Journals (Sweden)

    H Ijad panah

    2012-03-01

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

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

    Energy Technology Data Exchange (ETDEWEB)

    1992-08-01

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

  6. Development of highly faceted reduced graphene oxide-coated copper oxide and copper nanoparticles on a copper foil surface

    Science.gov (United States)

    Matsumoto, Yasuhiro; Espinoza-Rivas, Andrés M; Pérez-Guzmán, Manuel A; Ortega-López, Mauricio

    2016-01-01

    Summary This work describes the formation of reduced graphene oxide-coated copper oxide and copper nanoparticles (rGO-Cu2ONPs, rGO-CuNPs) on the surface of a copper foil supporting graphene oxide (GO) at annealing temperatures of 200–1000 °C, under an Ar atmosphere. These hybrid nanostructures were developed from bare copper oxide nanoparticles which grew at an annealing temperature of 80 °C under nitrogen flux. The predominant phase as well as the particle size and shape strongly depend on the process temperature. Characterization with transmission electron microscopy and scanning electron microscopy indicates that Cu or Cu2O nanoparticles take rGO sheets from the rGO network to form core–shell Cu–rGO or Cu2O–rGO nanostructures. It is noted that such ones increase in size from 5 to 800 nm as the annealing temperature increases in the 200–1000 °C range. At 1000 °C, Cu nanoparticles develop a highly faceted morphology, displaying arm-like carbon nanorods that originate from different facets of the copper crystal structure. PMID:27547618

  7. Effect of magnesium in aluminum alloys on characteristics of microarc oxidation coatings

    Institute of Scientific and Technical Information of China (English)

    LIU Yao-hui; LI Song; YU Si-rong; ZHU Xian-yong; XU Bai-ming

    2006-01-01

    Microarc oxidation(MAO) coatings were prepared on the surface of aluminum alloys with different contents of magnesium. The morphologies and surface roughness of the coatings were characterized by Confocal laser scanning microscopy(CLSM). Phase and chemical composition of the MAO coatings were analyzed by X-ray diffractometry(XRD) and X-ray photoelectron spectroscopy(XPS). The experimental results show that the coatings formed on different substrates have two-layer morphologies and are mainly composed of Al2O3 and Al-Si-O phases. In addition, the content of Al2O3 increases with increasing the content of magnesium. XPS results prove that magnesium from substrate indeed participates in the MAO process and is incorporated into the coating in the form of MgO. The coating formed on Al-3Mg substrate has the smallest mass loss and the lowest friction coefficient of 0.17-0.19.

  8. Preparation of Chromium Oxide Coatings on Aluminum Borate Whiskers by a Hydrothermal Deposition Process

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    Aluminum borate whiskers (9Al2O32B2O3) can be used to reinforce aluminum alloys to produce light and strong composites. However, the adverse interfacial reactions between the whiskers and the aluminum alloys inhibit their practical uses; therefore, a protective coating is needed on whiskers. In this work, aluminum borate whiskers were coated with chromium-coating deposits in a hydrothermal solution containing CrCl3, Na2C4H4O6, NaPH2O2, and H3BO3. The presence of the impurity P in the hydrothermal deposits can be avoided by reducing the amount of NaPH2O2 in the coating solution. Thermodynamic analysis was used to discuss the behavior of ions in the coating process. The subsequent heating of the hydrothermal products in air at 800 ℃ yielded smooth Cr2O3 films with a thickness of 0.060.07 μm.

  9. Structure and properties of carbonaceous adsorbents obtained from furanformolites

    Energy Technology Data Exchange (ETDEWEB)

    Pokonova, Y.B.; Oleinik, M.S.; Proskuryakov, V.A.

    1982-12-10

    We have shown previously (1) that a new copolycondensate based on petroleum residues -- fuaranformolite -- is a valuable carbon-containing raw material by the use of which carbonaceous adsorbents have been obtained. The latter can be used as catalysts and catalyst supports and also for the fine purification and separation of gases. The present paper is devoted to the study of the porous structure and sorption characteristics of the adsorbents obtained. High-strength carbonaceous adsorbents obtained from new copolymers of asphaltite -- fuaranformolites may, depending on the degree of burn-off, be used for the adsorption of poorly sorbed gases, of vapors of organic solvents, and of substances from solution. By varying the composition of the copolymer it is possible to direct the formation of the porous structure of the adsorbents in a desired manner.

  10. Corrosion, ion release and Mott-Schottky probe of chromium oxide coatings in saline solution with potential for orthopaedic implant applications

    Science.gov (United States)

    Ogwu, A. A.; Oje, A. M.; Kavanagh, J.

    2016-04-01

    We report our investigation on chromium oxide thin film coatings that show a negligible ion release during electrochemical corrosion testing in saline solution. The chemical constituents of the films prepared by reactive magnetron sputtering were identified to be predominantly Cr2O3 based on Raman spectroscopy anti-symmetric stretching vibration modes for CrIII-O and other peaks and an FTIR spectroscopy E u vibrational mode at 409 cm-1. X-ray photoelectron spectroscopy, multiplet fitting for 2P 3/2 and 2P 1/2 states also confirmed the predominantly Cr2O3 stoichiometry in the films. The prepared chromium oxide coatings showed superior pitting corrosion resistance compared to the native chromium oxide films on bare uncoated stainless steel when tested under open circuit potential, potentiodynamic polarisation and cyclic voltammetry in saline solution. The chromium ion released into solution during the corrosion testing of stainless steel substrates coated with chromium oxide coatings was found to be negligibly small based on atomic absorption spectroscopy measurements. Our Mott-Schottky analysis investigation showed that the negligibly small ion release from the chromium oxide coated steel substrates is most likely due to a much lower defect density on the surface of the deposited coatings compared to the native oxide layer on the uncoated steel substrates. This opens up the opportunity for using chromium oxide surface coatings in hip, knee and other orthopaedic implants where possible metal ion release in vivo still poses a great challenge.

  11. Preparation of Si-containing oxide coating and biomimetic apatite induction on magnesium alloy

    Science.gov (United States)

    Yu, Huijun; Dong, Qing; Dou, Jinhe; Pan, Yaokun; Chen, Chuanzhong

    2016-12-01

    Magnesium and its alloys are recently found important in the field of bone repairing for their ideal mechanical performance and excellent biocompatibility. Micro-arc oxidation (MAO) is a simple, controllable and efficient electrochemistry method that can prepare protective ceramic coatings on magnesium alloys. The properties of the MAO coating, such as thickness, microstructure, roughness and composition, can easily be controlled by adjusting the voltage, current density, duration or the electrolyte concentration. In this work, MAO coatings are prepared on ZK61 magnesium alloy at different voltages. The structure characteristics and element distributions of the coating are investigated by XRD, TEM, SEM and EPMA. The MAO samples are immersed in SBF for 7, 14 and 28 days respectively. The corrosion behaviors of the samples in SBF were also investigated by potentiodynamic polarization curves. The corrosion products were characterized by EDS and FT-IR. The MAO coated ZK61 alloy samples showed excellent corrosion resistance and bioactivity. The MAO method demonstrates a great potential in the preparation of degradable and bioactive orthopedic magnesium-based implants.

  12. Formation of Soluble Mercury Oxide Coatings: Transformation of Elemental Mercury in Soils.

    Science.gov (United States)

    Miller, Carrie L; Watson, David B; Lester, Brian P; Howe, Jane Y; Phillips, Debra H; He, Feng; Liang, Liyuan; Pierce, Eric M

    2015-10-20

    The impact of mercury (Hg) on human and ecological health has been known for decades. Although a treaty signed in 2013 by 147 nations regulates future large-scale mercury emissions, legacy Hg contamination exists worldwide and small-scale releases will continue. The fate of elemental mercury, Hg(0), lost to the subsurface and its potential chemical transformation that can lead to changes in speciation and mobility are poorly understood. Here, we show that Hg(0) beads interact with soil or manganese oxide solids and X-ray spectroscopic analysis indicates that the soluble mercury coatings are HgO. Dissolution studies show that, after reacting with a composite soil, >20 times more Hg is released into water from the coated beads than from a pure liquid mercury bead. An even larger, >700 times, release occurs from coated Hg(0) beads that have been reacted with manganese oxide, suggesting that manganese oxides are involved in the transformation of the Hg(0) beads and creation of the soluble mercury coatings. Although the coatings may inhibit Hg(0) evaporation, the high solubility of the coatings can enhance Hg(II) migration away from the Hg(0)-spill site and result in potential changes in mercury speciation in the soil and increased mercury mobility.

  13. Removal of Trace Arsenic to Meet Drinking Water Standards Using Iron Oxide Coated Multiwall Carbon Nanotubes.

    Science.gov (United States)

    Ntim, Susana Addo; Mitra, Somenath

    2011-05-12

    This study presents the removal of trace level arsenic to meet drinking water standards using an iron oxide-multi-walled carbon nanotube (Fe-MWCNT) hybrid as a sorbent. The synthesis was facilitated by the high degree of nanotube functionalization using a microwave assisted process, and a controlled assembly of iron oxide was possible where the MWCNT served as an effective support for the oxide. In the final product, 11 % of the carbon atoms were attached to Fe. The Fe-MWCNT was effective in arsenic removal to below the drinking water standard levels of 10 µg L(-1). The absorption capacity of the composite was 1723 µg g(-1) and 189 µg g(-1) for As(III) and As(V) respectively. The adsorption of As(V) on Fe-MWCNT was faster than that of As(III). The pseudo-second order rate equation was found to effectively describe the kinetics of arsenic adsorption. The adsorption isotherms for As(III) and As(V) fitted both the Langmuir and Freundlich models.

  14. Preparation and characterization of a novel adsorbent for removing lipophilic organic from water

    Institute of Scientific and Technical Information of China (English)

    LIU; Huijuan; DAI; Ruihua; QU; Jiuhui; RU; Jia

    2005-01-01

    A novel composite adsorbent containing a kind of lipid-triolein is studied. The adsorbent is prepared by embedding triolein into cellulose acetate (CA) sphere. The preparation method, the physical-chemical properties of the adsorbent and the removal efficiency of two organochlorinated pesticides are studied. The adsorbent is stable in water and no triolein leaks into water for 465 h soaking. The adsorbent has high adsorption capacity for organochlorinated pesticides such as dieldrin and aldrin. The results suggest that triolein-containing adsorbent could serve as a good adsorbent for lipophilic organic pollutants. The adsorption rate for lipophilic pollutants is very fast and has relation with the logKow of the compounds.

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

    Directory of Open Access Journals (Sweden)

    Heuck, Claus-Chr.

    2011-01-01

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

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

    Science.gov (United States)

    Heuck, Claus-Chr

    2011-01-24

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

  17. 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.

  18. Nano-Structured Magnesium Oxide Coated Iron Ore: Its Application to the Remediation of Wastewater Containing Lead.

    Science.gov (United States)

    Nagarajah, Ranjini; Jang, Min; Pichiah, Saravanan; Cho, Jongman; Snyder, Shane A

    2015-12-01

    Magnetically separable nano-structured magnesium oxide coated iron ore (IO(MgO)) was prepared using environmentally benign chemicals, such as iron ore (IO), magnesium(II) nitrate hexahydrate [Mg(NO3)2 x 6H2O] and urea; via an easy and fast preparation method. The lO(MgO) was characterized using X-ray diffraction (XRD), field-emission scanning electron microscopy (FE-SEM), energy-dispersive X-ray spectroscopy (EDS) and alternating gradient magnetometer (AGM) analyses. The isotherm and kinetic studies indicated that lO(MgO) has a comparably higher Langmuir constant (K(L), 1.69 L mg(-1)) and maximum sorption capacity (33.9 mg g(-1)) for lead (Pb) than other inorganic media. Based on MgO amount, the removal capacity of Pb by IO(MgO) was 2,724 mg Pb (g MgO)(-1), which was higher than that (1,980 mg g(-1)) for flowerlike magnesium oxide nanostructures reported by Cao et al. The kinetics, FE-SEM, elemental mapping and XRD results revealed that the substitution followed by precipitation was identified as the mechanism of Pb removal and plumbophyllite (Pb2Si4O10 x H2O) was the precipitated phase of Pb. A leaching test revealed that IOMgO) had negligible concentrations of leached Fe at pH 4-9. Since the base material, IO, is cheap and easily available, lO(MgO) could be produced in massive amounts and used for remediation of wastewater containing heavy metals, applying simple and fast magnetic separation.

  19. 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 γβ≈30% and a range of approximately 1mm in biological tissue for the 1.3MeV β-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.

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

    Science.gov (United States)

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

    2013-12-01

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

  1. Membrane adsorber for endotoxin removal

    Directory of Open Access Journals (Sweden)

    Karina Moita de Almeida

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

  2. Effect of Oxide Coating on Performance of Copper-Zinc Oxide-Based Catalyst for Methanol Synthesis via Hydrogenation of Carbon Dioxide

    Directory of Open Access Journals (Sweden)

    Tetsuo Umegaki

    2015-11-01

    Full Text Available The effect of oxide coating on the activity of a copper-zinc oxide–based catalyst for methanol synthesis via the hydrogenation of carbon dioxide was investigated. A commercial catalyst was coated with various oxides by a sol-gel method. The influence of the types of promoters used in the sol-gel reaction was investigated. Temperature-programmed reduction-thermogravimetric analysis revealed that the reduction peak assigned to the copper species in the oxide-coated catalysts prepared using ammonia shifts to lower temperatures than that of the pristine catalyst; in contrast, the reduction peak shifts to higher temperatures for the catalysts prepared using L(+-arginine. These observations indicated that the copper species were weakly bonded with the oxide and were easily reduced by using ammonia. The catalysts prepared using ammonia show higher CO2 conversion than the catalysts prepared using L(+-arginine. Among the catalysts prepared using ammonia, the silica-coated catalyst displayed a high activity at high temperatures, while the zirconia-coated catalyst and titania-coated catalyst had high activity at low temperatures. At high temperature the conversion over the silica-coated catalyst does not significantly change with reaction temperature, while the conversion over the zirconia-coated catalyst and titania-coated catalyst decreases with reaction time. From the results of FTIR, the durability depends on hydrophilicity of the oxides.

  3. Black Sprayable Molecular Adsorber Coating Project

    Data.gov (United States)

    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...

  4. Thickness effects on corrosion and wear resistance properties of micro-arc discharge oxide coatings on AZ91D magnesium alloys

    Institute of Scientific and Technical Information of China (English)

    HUANG Wei-jiu; LIU Ming; LI Zhao-feng; ZENG Rong-chang

    2006-01-01

    The microarc oxidation coatings with difference thickness were synthesized on AZ91D magnesium alloy. The microstructure and phase structure of the coatings were analyzed using SEM and XRD, the tribological properties and corrosion resistance behaviour of the coatings were also investigated. The results show that the coating contains two layers, a porous outer layer and relatively dense inner layer. The microhardness of the MAO coatings is four to six times higher than that of the magnesium alloy substrate. The MAO coatings have much better wear-resistance and corrosion resistance abilities than those of magnesium alloy substrate, but possess higher friction coefficient. The results further indicate that there is an optimization thickness for corrosion and wear resistance.

  5. Effects of metal oxide coatings on the thermal stability and electrical performance of LiCoCO 2 in a Li-ion cell

    Science.gov (United States)

    Kweon, Ho-Jin; Park, JeonJoon; Seo, JunWon; Kim, GeunBae; Jung, BokHwan; Lim, Hong S.

    A study is made of the effects of MgO and Al 2O 3 coatings on the electrical properties of LiCoO 2 cathode material on the thermal stability (differential scanning calorimetry (DSC)) of the charged cathode, and on the safety characteristics of 18650 Li-ion cells. Powdery active material is coated with Mg or Al alkoxide solutions followed by heat treatment in air at temperatures between 300 and 800 °C. The presence of the coating is confirmed by an elemental depth-profile analysis of the powder surface using secondary ion mass spectroscopy (SIMS) and X-ray photoelectron spectroscopy (XPS). Both oxide coatings, especially the Al 2O 3 coating, substantially improve the charge-discharge voltage characteristics, rate capability, capacity and rate-capability retention on cycling and thermal stability of the LiCoO 2 cathode. These beneficial effects are demonstrated in 18650 Li-ion cells.

  6. 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.

  7. Composition

    DEFF Research Database (Denmark)

    Bergstrøm-Nielsen, Carl

    2014-01-01

    Cue Rondo is an open composition to be realised by improvising musicians. See more about my composition practise in the entry "Composition - General Introduction". Caution: streaming the sound/video files will in some cases only provide a few minutes' sample, or the visuals will not appear at all...

  8. Composition

    DEFF Research Database (Denmark)

    Bergstrøm-Nielsen, Carl

    2011-01-01

    Strategies are open compositions to be realised by improvising musicians. See more about my composition practise in the entry "Composition - General Introduction". Caution: streaming the sound files will in some cases only provide a few minutes' sample. Please DOWNLOAD them to hear them in full...

  9. Composition

    DEFF Research Database (Denmark)

    Bergstrøm-Nielsen, Carl

    2010-01-01

    New Year is an open composition to be realised by improvising musicians. It is included in "From the Danish Seasons" (see under this title). See more about my composition practise in the entry "Composition - General Introduction". This work is licensed under a Creative Commons "by-nc" License. You...

  10. Experimental study of a three-adsorber sorption refrigerator for utilization of renewable sources of energy

    Science.gov (United States)

    Tsitovich, A. P.

    2013-03-01

    A three-adsorber refrigerator has been created and experimentally tested, in which use is made of a composite sorbent consisting of activated carbon fiber and alkali salts. This sorbent has a high capacity of storage of refrigeration characteristic of chemical coolers and a high sorption rate characteristic of adsorption refrigerators. The sorbent structure makes it possible to effect a convective intrapore process of cooling of the sorbent through intense two-phase heat transfer. A three-adsorber refrigerator has a higher refrigeration efficiency and smaller mass and overall dimensions than a traditional two-stage four-adsorber refrigerator.

  11. 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.

  12. Microporous carbonaceous adsorbents for CO2 separation via selective adsorption

    KAUST Repository

    Zhao, Yunfeng

    2015-01-01

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

  13. Nanoalloy electrocatalysis: simulating cyclic voltammetry from configurational thermodynamics with adsorbates.

    Science.gov (United States)

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

    2015-11-14

    We simulate the adsorption isotherms for alloyed nanoparticles (nanoalloys) with adsorbates to determine cyclic voltammetry (CV) during electrocatalysis. The effect of alloying on nanoparticle adsorption isotherms is provided by a hybrid-ensemble Monte Carlo simulation that uses the cluster expansion method extended to non-exchangeable coupled lattices for nanoalloys with adsorbates. Exemplified here for the hydrogen evolution reaction, a 2-dimensional CV is mapped for Pd-Pt nanoalloys as a function of both electrochemical potential and the global Pt composition, and shows a highly non-linear alloying effect on CV. Detailed features in CV arise from the interplay among the H-adsorption in multiple sites that is closely correlated with alloy configurations, which are in turn affected by the H-coverage. The origins of specific features in CV curves are assigned. The method provides a more complete means to design nanoalloys for electrocatalysis.

  14. 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.

  15. Synthesis and performance evaluation of Al/Fe oxide coated diatomaceous earth in groundwater defluoridation: Towards fluorosis mitigation.

    Science.gov (United States)

    Izuagie, Anthony A; Gitari, Wilson M; Gumbo, Jabulani R

    2016-08-23

    The quest to reduce fluoride in groundwater to WHO acceptable limit of 1.5 mg/L to prevent diseases such as teeth mottling and skeletal fluorosis was the motivation for this study. Al/Fe oxide-modified diatomaceous earth was prepared and its defluoridation potential evaluated by batch method. The sorbent with pHpzc 6.0 ± 0.2 is very reactive. The maximum 82.3% fluoride removal attained in 50 min using a dosage of 0.3 g/100 mL in 10 mg/L fluoride was almost attained within 5 min contact time; 81.3% being the percent fluoride removal at 5 min contact time. The sorbent has a usage advantage of not requiring solution pH adjustment before it can exhibit its fluoride removal potential. A substantial amount of fluoride (93.1%) was removed from solution when a sorbent dosage of 0.6 g/100 mL was contacted with 10 mg/L fluoride solution for 50 min at a mixing rate of 200 rpm. The optimum adsorption capacity of the adsorbent was 7.633 mg/g using a solution containing initially 100 mg/L fluoride. The equilibrium pH of the suspensions ranged between 6.77 and 8.26 for 10 and 100 mg/L fluoride solutions respectively. Contacting the sorbent at a dosage of 0.6 g/100 mL with field water containing 5.53 mg/L at 200 rpm for 50 min reduced the fluoride content to 0.928 mg/L-a value below the upper limit of WHO guideline of 1.5 mg/L fluoride in drinking water. The sorption data fitted to both Langmuir and Freundlich isotherms but better with the former. The sorption data obeyed only the pseudo-second-order kinetic, which implies that fluoride was chemisorbed.

  16. Effects of Surface Coating Preparation and Sliding Modes on Titanium Oxide Coated Titanium Alloy for Aerospace Applications

    Directory of Open Access Journals (Sweden)

    Bo Yuan Peng

    2014-01-01

    electrolytic oxidation (PEO. During the PEO procedure, a composition of silicate and phosphate was used as the electrolyte. In order to evaluate the coating, pin-on-disk (POD tribology tests and cyclic inclined sliding tests were used under dry room conditions. Furthermore, scanning electron microscopy (SEM and energy dispersive spectroscopy (EDS were utilized to examine the morphology and composition of the coating surfaces. The results of the POD tests revealed that the PEO coating could have a low coefficient of friction and suggested that high silicon concentrations in the PEO coatings take away oxygen from stoichiometric Ti oxides to create lubricating oxides. In addition, cyclic inclined sliding tests showed that smaller pores on the surface of the coating could permit a higher coating cohesive strength and allow the coated Ti alloy surface to perform better under high inclined sliding forces.

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

    Science.gov (United States)

    Kumar, Yogesh; Herrera-Zaldivar, Manuel; Olive-Méndez, Sion Federico; Singh, Fouran; Mathew, Xavier; Agarwal, Vivechana

    2012-07-02

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

  18. 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.

  19. Effect of Dissolvable Humic Acid on Benzotriazole Sorption by Iron Oxide Coated Quartz Sands%水溶性腐植酸对石英砂负载氧化铁吸附苯并三唑的影响

    Institute of Scientific and Technical Information of China (English)

    赵晓丽; 毕二平

    2015-01-01

    Dissolvable humic acid(DHA)plays an important role in sorption of pollutants in the environment. The effects of cation type and DHA concentration on sorption of DHA and benzotriazole(BTA)on iron oxide coated quartz sands(IOCQS)were studied using batch ex-periments. At the solution pH 6.0, electrostatic interaction plays an important role in the sorption of DHA by IOCQS. The isotherms of BTA sorption by IOCQS could be well described by Freundlich model. The effect of DHA on sorption of BTA was strongly determined by DHA concentration and electrolyte type. At 0~15.68 mg·L-1 of DHA concentration, DHA enhanced sorption of BTA on IOCQS in 0.01 mol·L-1 CaCl2 solution. Such enhancement was mainly resulted from cumulative sorption. Under different background electrolytes, the amount of ad-sorbed DHA was different, and the effect of DHA on BTA sorption by IOCQS was consequently different.%水溶性腐植酸(DHA)对环境中污染物的吸附有重要影响。通过批实验研究了阳离子类型、DHA浓度等因素对石英砂负载氧化铁吸附DHA和苯并三唑(BTA)的影响。结果表明:在溶液pH为6.0时,静电作用在石英砂负载氧化铁吸附DHA的过程中起重要作用,Freundlich模型能很好地描述石英砂负载氧化铁对BTA的吸附;DHA对石英砂负载氧化铁吸附BTA的影响程度与DHA浓度和电解质类型有关,当DHA浓度在0~15.68 mg·L-1范围时,在以0.01 mol·L-1 CaCl2为背景电解质的溶液中,DHA浓度越大,其促进BTA吸附越明显;DHA通过累积吸附作用,促进石英砂负载氧化铁对BTA的吸附;在不同的电解质溶液中,石英砂负载氧化铁对DHA的吸附量不同,从而对石英砂负载氧化铁吸附BTA的影响也不同。

  20. Binder-free graphene and manganese oxide coated carbon felt anode for high-performance microbial fuel cell.

    Science.gov (United States)

    Zhang, Changyong; Liang, Peng; Yang, Xufei; Jiang, Yong; Bian, Yanhong; Chen, Chengmeng; Zhang, Xiaoyuan; Huang, Xia

    2016-07-15

    A novel anode was developed by coating reduced graphene oxide (rGO) and manganese oxide (MnO2) composite on the carbon felt (CF) surface. With a large surface area and excellent electrical conductivity, this binder-free anode was found to effectively enhance the enrichment and growth of electrochemically active bacteria and facilitate the extracellular electron transfer from the bacteria to the anode. A microbial fuel cell (MFC) equipped with the rGO/MnO2/CF anode delivered a maximum power density of 2065mWm(-2), 154% higher than that with a bare CF anode. The internal resistance of the MFC with this novel anode was 79Ω, 66% lower than the regular one's (234Ω). Cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) analyses affirmed that the rGO/MnO2 composite significantly increased the anodic reaction rates and facilitated the electron transfer from the bacteria to the anode. The findings from this study suggest that the rGO/MnO2/CF anode, fabricated via a simple dip-coating and electro-deposition process, could be a promising anode material for high-performance MFC applications.

  1. The capture and destruction of Escherichia coli from simulated urban runoff using conventional bioretention media and iron oxide-coated sand.

    Science.gov (United States)

    Zhang, Lan; Seagren, Eric A; Davis, Allen P; Karns, Jeffrey S

    2010-08-01

    The performance, sustainability, and mechanisms of bacterial removal from stormwater runoff by bioretention systems are poorly understood. The potential for removal of microorganisms in bioretention systems was evaluated using column studies and simulated urban stormwater runoff. Conventional bioretention media (CBM) removed 82% of Escherichia coli O157:H7 strain B6914 cells; iron-oxide coated sand (IOCS) significantly enhanced capture, with 99% efficiency. This improvement possibly was because of the greater positive surface charge and roughness, of the IOCS. Trapped strain B6914 cells decayed more rapidly in CBM, however, with more than 99.98% die-off within one week compared with the IOCS in which approximately 48% of trapped cells survived. Predation and competition from native microorganisms in CBM were verified to play a dominant role in rapid destruction of trapped strain B6914. In particular, protozoan grazing appeared to play an important role, with the die-off of trapped B6914 increasing with increasing concentrations of protozoa.

  2. EMISSION REDUCTION FROM A DIESEL ENGINE FUELED BY CERIUM OXIDE NANO-ADDITIVES USING SCR WITH DIFFERENT METAL OXIDES COATED CATALYTIC CONVERTER

    Directory of Open Access Journals (Sweden)

    B. JOTHI THIRUMAL

    2015-11-01

    Full Text Available This paper reports the results of experimental investigations on the influence of the addition of cerium oxide in nanoparticle form on the major physiochemical properties and the performance of diesel. The fuel is modified by dispersing the catalytic nanoparticle by ultrasonic agitation. The physiochemical properties of sole diesel fuel and modified fuel are tested with ASTM standard procedures. The effects of the additive nanoparticles on the individual fuel properties, the engine performance, and emissions are studied, and the dosing level of the additive is optimized. Cerium oxide acts as an oxygen-donating catalyst and provides oxygen for the oxidation of CO during combustion. The active energy of cerium oxide acts to burn off carbon deposits within the engine cylinder at the wall temperature and prevents the deposition of non-polar compounds on the cylinder wall which results in reduction in HC emission by 56.5%. Furthermore, a low-cost metal oxide coated SCR (selective catalyst reduction, using urea as a reducing agent, along with different types of CC (catalytic converter, has been implemented in the exhaust pipe to reduce NOx. It was observed that a reduction in NOx emission is 50–60%. The tests revealed that cerium oxide nanoparticles can be used as an additive in diesel to improve complete combustion of the fuel and reduce the exhaust emissions significantly.

  3. 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.

  4. Chemical Modifications of Cassava Peel as Adsorbent Material for Metals Ions from Wastewater

    Directory of Open Access Journals (Sweden)

    Daniel Schwantes

    2016-01-01

    Full Text Available Residues from the processing of cassava roots (Manihot esculenta Crantz, or cassava peels, are evaluated as chemically modified adsorbents with H2O2, H2SO4, and NaOH, in the removal of metal ions Cd(II, Pb(II, and Cr(III from contaminated water. Modified adsorbents were chemically characterized for their chemical composition and pHPZC (point of zero charge, while adsorption tests determined the best conditions of pH, adsorbent mass, and contact time between adsorbent and adsorbate in the process of removal of the metal ions. Isotherms obtained from the preliminary results were linearized by Langmuir’s and Freudlich’s models. The thermodynamic parameters, such as ΔH, ΔG, and ΔS, were also evaluated. The modifying solutions proposed were effective in the modification of adsorbents and resulted in high capacity sorption materials. Equilibrium time between adsorbent and adsorbate for the solutions contaminated with metals is about 40 minutes. The Langmuir model adjusted to most results, indicating monolayers adsorption of Cd(II, Pb(II, and Cr(III. The values obtained for Langmuir Qm show a higher adsorption capacity caused by chemical modifications, with values such as 19.54 mg Cd(II per g of M. NaOH, 42.46 mg of Pb(II per g of M. NaOH, and 43.97 mg of Cr(III per g of M H2O2. Results showed that modified cassava peels are excellent adsorbent, renewable, high availability, and low-cost materials and a feasible alternative in the removal of metals in industries.

  5. Effects of Anodic Voltages on Microstructure and Properties of Plasma Electrolytic Oxidation Coatings on Biomedical NiTi Alloy

    Institute of Scientific and Technical Information of China (English)

    Jilin Xu; Fu Liu; Junming Luo; Liancheng Zhao

    2013-01-01

    Plasma electrolytic oxidation (PEO) coatings,formed under various anodic voltages (320-440 V) on biomedical NiTi alloy,are mainly composed of γ-Al2O3 crystal phase.The evolution of discharging sparks during the PEO process under different anodic voltages was observed.The surface and cross-sectional morphologies,composition,bonding strength,wear resistance and corrosion resistance of the coatings were investigated by scanning electron microscopy (SEM),thin-film X-ray diffraction (TF-XRD),energy dispersive X-ray spectrometry (EDS),surface roughness,direct pull-off test,ball-on-disk friction and wear test and potentiodynamic polarization test,respectively.The results showed that the evolution of discharging sparks during the PEO process directly influenced the microstructure of the PEO coatings and further influences the properties.When the anodic voltage increased from 320 V to 400 V,the corrosion resistance and wear resistance of the coatings slowly increased,and all the bonding strength was higher than 60 MPa; further increasing the anodic voltages,especially up to 440 V,although the thickness and γ-Al2O3 crystallinity of the coatings further increased,the microstructure and properties of the coatings were obviously deteriorated.

  6. 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 γ-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.

  7. Chitin Adsorbents for Toxic Metals: A Review

    Directory of Open Access Journals (Sweden)

    Ioannis Anastopoulos

    2017-01-01

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

  8. IR investigations of surfaces and adsorbates

    CERN Document Server

    Gwyn, W

    2001-01-01

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

  9. Behavior of macromolecules in adsorbed layers

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    A model for describing the behavior of macromolecules in adsorbed layers is developed by introducing a concept of distribution density of layer thickness U based on stochastic process and probabilistic statistics. The molecular behavior of layers adsorbed on clay particle surfaces is discussed; the random distribution and its statistics of the layer thickness are given by incorporating experimental results with an ionic polyelectrolyte with the molecular weight of 1.08×106 and chain charged density of 0.254.

  10. 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.

  11. ADSORBENTS USED IN THE CLEARANCE OF ENDOTOXIN

    Institute of Scientific and Technical Information of China (English)

    YU Mei; LIU Tao; Hou Guanghui; YUAN Zhi

    2003-01-01

    A series of modified poly (methyl methacrylate, PMMA) resins were prepared and compared their adsorption abilities to endotoxin. The results showed that adsorbents, which were grafted with tertiary amine and long spacing arms, had the best adsorption capacities and good blood compatibility, It is hopeful to be used as adsorbent in hemoperfusion for clinical clearance of endotoxin. The influence of original concentration of endotoxin on adsorption and the adsorption mechanism were also investigated.

  12. Dissolved Air Flotation of arsenic adsorbent particles

    Directory of Open Access Journals (Sweden)

    M. Santander

    2015-04-01

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

  13. The Dynamics and Structures of Adsorbed Surfaces

    DEFF Research Database (Denmark)

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

    1978-01-01

    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...

  14. Preparation of Zr,Al,Ti composite oxide adsorbents and their adsorption properties of EDTA-Cr%不同比例Zr、Al、Ti复合氧化物的制备及其对EDTA-Cr的吸附性能研究

    Institute of Scientific and Technical Information of China (English)

    马宏瑞; 马秀; 郭颖燕; 唐志刚

    2014-01-01

    Composite oxide adsorbents of ZrO2-A12 O3-TiO2 , with mesoporous , were pre-pared by co-precipitation method and characterized by TG-DSC ,X-ray diffraction ,BET and pore size analysis to investigate the effects of calcination temperature ,and time on the prop-erties of prepared composite oxides .The results showed that composite oxides synthesized with different metal proportions hold different temperatures of crystallization and crystal transformation .EDTA-Cr (1∶1 .25) was simulated ,under the experimental conditions ,as chromium tanning wastewater to evaluate the adsorping efficiencies of the composite oxides , w hich indicated that composite oxides calcinated at 750 ℃ for 3 hours absorbed more chromi-um with increasing addition of chromium and reached a maximum adsorption equilibrium of 167 mg/g .It is proved to be available to remove EDTA-Cr by our prepared absorbents .%采用共沉淀法制备纳米介孔ZrO2-Al2 O3-TiO2(记为Zr-A1-Ti)复合氧化物吸附剂,摩尔浓度比分别为2∶2∶1、3∶1∶1、1∶3∶1.考察750℃焙烧3 h对复合氧化物性能的影响,并采用热重分析、示差热分析、X射线衍射和比表面积及孔径测定对复合氧化物进行表征.结果表明,不同金属比例合成的复合氧化物具有不同的晶化温度及晶型转化温度.在实验室模拟EDTA-Cr(1∶1.25)条件下对制备的各复合氧化物吸附剂进行了评价:经750℃焙烧3 h所制得复合氧化物吸附剂对ED T A-铬的吸附在实验铬浓度条件下,随着铬浓度的增加吸附量增大,最大吸附量达到167 mg/g .综上可得所制备吸附剂对EDTA-Cr的去除是可行的.

  15. 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

  16. 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.

  17. 硅藻土/WO-PAM复合吸附剂制备及去除铯性能研究%Synthesis of Diatomite/WO-PAM Composite Adsorbent and Its Performance for Cesium Removal

    Institute of Scientific and Technical Information of China (English)

    杜玉成; 孙广兵; 郑广伟

    2015-01-01

    以硅藻土、丙烯酰胺/乙烯基阳(阴)离子单体共聚物为原料,以N,N-亚甲基双丙烯酰胺为交联剂、偶氮二异丁腈为引发剂,采用化学合成法制备了两种硅藻土/WO-PAM复合吸附剂。采用SEM、EDS、BET、FT-IR等对样品进行了表征,研究了样品对133Cs吸附规律。样品比表面积分别为88 m2/g、92 m2/g,133Cs的最大容量分别为165 mg/g、217 mg/g,初始质量浓度为10 mg/L的含133Cs污水,一次吸附去除率均达99%。%In this work, two composite absorbents, including diatomite/WO-cation PAM and diatomite/WO-anion PAM were prepared via chemical synthesis method by using N, N-methylene bis acrylamide as crosslinking agent and azodiisobutyronitrile as evocating agent. The samples were characterized by scanning electron microscope (SEM), energy-dispersive X-ray spectroscopy (EDS), Brunauer-Emmett-Teller (BET), and Fourier transform infrared spectrometry (FT-IR). With CsCl as the source of133Cs, the adsorption behavior for133Cs of the two samples was investigated. It was found that the surface areas of the two samples were 88 and 92m2/g, respectively, and the maximum adsorption capacity for133Cs were 165 and 217mg/g, respectively. As initial concentration of133Cs was 10mg/L, the removal efifciency of both the diatomite/WO-cation PAM and diatomite/WO-anion PAM for133Cs was 99%.

  18. POTENTIAL USE OF WOOL WASTE AS ADSORBENT FOR THE REMOVAL OF ACID DYES FROM WASTEWATER

    Directory of Open Access Journals (Sweden)

    BUCIŞCANU Ingrid

    2016-05-01

    Full Text Available At present, great amounts of raw wool are treated as waste and raise disposal problems. In the sustainable development context , wool is regarded as a biodegradable renewable resource and due to its complex chemical composition and fiber morphology, can find different useful applications. It is the aim of this paper to investigate the potential use of raw wool waste as a non-conventional adsorbent for Acid Red 337(AcR ,currently used for leather and wool dyeing. Two wool-based adsorbents were prepared, namely scoured coarse wool (Wool-S and wool activated with alcoholic solution of sodium hydroxide (Wool-A. Adsorbent dosage, dye concentration, pH and treatment time were factors taken in consideration for the assessment of the sorbate-adsorbent interaction. The removal efficiency (R % is mainly dependent on the solution pH and on the activation treatment applied to wool: at pH 3, the removal efficiency reaches the highest values of 42% on Wool-S and 99% on Wool-A. The adsorption rate is slow and needs almost 6 h to reach equilibrium. The experimental data best fitted the Langmuir equilibrium adsorption model, which proves that the adsorbent possess surface active sites to which the dye sorbate binds in monomolecular layer. Raw wool waste is a potential cheap, biodegradable and effective adsorbent for colored wastewater treatment.

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

    Science.gov (United States)

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

    2007-09-01

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

  20. Adsorbent Selection by Functional Group Interaction Screening for Peptide Recovery

    NARCIS (Netherlands)

    Wijntje, Renze; Bosch, Hans; Haan, de Andre B.; Bussman, Paul

    2005-01-01

    In order to selectively adsorb small peptides from complex aqueous feeds, selective adsorbents are required. The goal is to first find adsorbents with capacity for triglycine, as triglycine contains all groups common to small peptides. Selectivity studies will follow. Adsorbent selection was based o

  1. Preparation of Polyacrylonitrile-potassium Cobalt/Titanium Hexacyanoferrate (Ⅱ) Spherical Composite Adsorbents and Their Adsorption Properties for Cs+%聚丙烯腈-亚铁氰化钾钴/钛球形复合吸附剂制备及其对 Cs +的吸附性能研究

    Institute of Scientific and Technical Information of China (English)

    杜志辉; 贾铭椿; 门金凤; 丰世彬

    2014-01-01

    Polyacrylonitrile-potassium cobalt/titanium hexacyanoferrate (Ⅱ ) spherical composite adsorbents (PAN-KCoCF and PAN-KTiCF) were prepared to remove cesium ions from aqueous solution . The effects of contact time ,pH ,competition ions and initial cesium concentration on cesium sorption were investigated via batch experiments . The adsorptive kinetics and isotherms were analyzed . The characterization of PAN-KCoCF and PAN-KTiCF were performed by SEM ,FT-IR ,XRD ,etc .The results show that the cesium sorption of PAN-KCoCF and PAN-KTiCF can reach equilibrium after about 16 h .With the increase of pH ,the cesium sorption of PAN-KTiCF increases fast at first and maintains at an almost constant value ,while the cesium sorption of PAN-KCoCF isn’t almost affected .Compared with PAN-KTiCF ,the cesium sorption of PAN-KCoCF is more selective when K + , Na+ , NH+4 , Ca2+ or Mg2+ is added to solution .The sorption kinetics of two adsorbents for Cs+ can be described by pseudo-second-order equation ,and the sorption rate is mainly controlled by surface adsorption . The sorption of two adsorbents for cesium is monolayer adsorption ,and the sorption data can be interpreted in terms of Langmuir isotherm . The saturated adsorption capacities of PAN-KCoCF and PAN-KTiCF are 128.370 mg/g and 278.552 mg/g , respectively .%本文合成了聚丙烯腈-亚铁氰化钾钴/钛球形复合吸附剂(PAN-KCoCF和 PAN-KTiCF),通过静态吸附实验,研究了接触时间、pH值、竞争离子、Cs+初始浓度等对 PAN-KCoCF和 PAN-KTiCF吸附Cs+效果的影响,分析了吸附过程的反应动力学和吸附等温线,并用扫描电镜(SEM )、傅里叶红外光谱(FT-IR)、X射线衍射仪(XRD)等对吸附剂进行了分析。结果表明,PAN-KCoCF 和 PAN-KTiCF对Cs+的吸附平衡时间均为16 h ,随着pH值的增加,PAN-KTiCF对Cs+的吸附量先快速增大,随后趋于平缓,而PAN-KCoCF对Cs+的吸附量几乎不变

  2. Black Molecular Adsorber Coatings for Spaceflight Applications

    Science.gov (United States)

    Abraham, Nithin Susan; Hasegawa, Mark Makoto; Straka, Sharon A.

    2014-01-01

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

  3. Acid yellow 9 as a dispersing agent for carbon nanotubes: preparation of redox polymer-carbon nanotube composite film and its sensing application towards ascorbic acid and dopamine.

    Science.gov (United States)

    Kumar, S Ashok; Wang, Sea-Fue; Yang, Thomas C-K; Yeh, Chun-Ting

    2010-08-15

    In this study, we show that acid yellow 9 (4-amino-1-1'-azobenzene-3,4'-disulfonicacid, AY) is a good stabilizing agent for multi-walled carbon nanotubes (MWCNTs). MWCNTs dispersed in AY solution was remained stable about three months and even remained stable after centrifugation at 10,000 rpm for 30 min. Using MWCNTs/AY dispersion, thin-films were prepared on indium tin oxide coated glass electrode and glassy carbon electrodes. Further, dried films of MWCNTs/AY were subjected to electropolymerization in 0.1M H(2)SO(4) solution. Adsorbed AY molecules on MWCNTs get polymerized and they yield a polymer-MWCNTs nanocomposite film on electrode surface which is found to be electrochemically active in wide pH range (1-11). Characterization studies were performed using cyclic voltammetry and SEM. These studies are supported that hybrid material PAY/MWCNTs was obtained. Moreover, newly synthesized PAY-MWCNTs composite film showed excellent electrocatalytic activity towards oxidation of dopamine (DA) and ascorbic acid (AA) with high sensitivity in physiological pH. Linear sweep voltammetry was employed to the determination of DA in the presence of AA in the range of 2x10(-7) to 1.4x10(-6) M. Amperometry was employed to determination of AA at 0.0 V in the range from 1x10(-6) to 5.6x10(-5) M, and DA, uric acid are not interfered on the steady-state current of AA. In addition, real samples such as dopamine injection and AA spiked into human urine were analyzed using PAY/MWCNTs composite modified electrode and satisfactory results were obtained.

  4. STUDY ON THE ADSORPTION OF OXIDATION OF CROSSLINKED β—CYCLODEXTRIN AND ITS CXOMPOSITE ADSORBENT WITH DIALYTIC MEMBRANE

    Institute of Scientific and Technical Information of China (English)

    ShiLinqi; HeBuinglin

    1997-01-01

    An urea adsorbent with an aldo structure was obtained by the oxidation of a crosslinked β-cyclodextrin polymer.The highest urea adsorption capacity reached 56.7mg/g in 0.05Maqueous phosphate buffer 37℃ and pH=7.4,and decrease to 4.8mg/g in in aqueous human serum albumin.The composite adsorbent was prepared by the oxidation of a crosslinked β-cyclodextrin and dialytic membrane.It was found that the composite adsorbent has a higher urea adsorption selectivity and capacity compared to that of the oxidation of a crosslinked β-cyclodextrin adsorbent when urea is in aqueous human serum albumin.

  5. Adsorbent catalytic nanoparticles and methods of using the same

    Energy Technology Data Exchange (ETDEWEB)

    Slowing, Igor Ivan; Kandel, Kapil

    2017-01-31

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

  6. 氧化铁改性石英砂的复合挂膜与氨氮去除试验研究%EXPERIMENTAL STUDY ON COMPOUND FORMATION AND REMOVAL AMMONIA NITROGEN USING IRON OXIDE COATED SANDS

    Institute of Scientific and Technical Information of China (English)

    李冬梅; 刘贝; 庞治星; 刘培涛; 刘雄威; 李绍秀

    2012-01-01

    采用自制的氧化铁改性石英砂滤料(简称“改性砂”),对生物改性砂联合处理微污染物氨氮的复合挂膜启动性能以及滤料表面形态进行了试验研究,并与生物普通砂联用效果进行对比.结果表明,生物普通砂和生物改性砂在挂膜初期的生物量分别为15.46、13.79 nmol/g(n(P)/m(滤料)),稳定运行期分别为18.75、20.09 nmol/g;挂膜初期,生物普通砂与生物改性砂对质量浓度为1~2 mg/L氨氮的去除效果分别达到92%和95%;挂膜稳定期,前者对氨氮的去除效果约60%,后者稳定在80%左右;在不同氨氮质量浓度(0.5~4 mg/L)下,生物普通砂对氨氮去除率从60%上升至80%,生物改性砂的去除率从70%增至95%;过滤前后2种滤料表面形态均发生变化,生物改性砂表面孔隙更小,结构更加复杂多孔,表面粗糙程度进一步增加,对氨氮去除率高.%A homemade iron oxide cCoated sands filters with biological was used to remove ammonia nitrogen from contaminated source water, the process of compound formation start-up and the surface morphology of the two filters was carried out, and contrasted with the effect of biological-raw sands. The results were shown as follows: The biomass of the biological- raw sand filter, and biological-iron oxide coated sand filter were 15.46 and 13.79 nmol/g in the initial of formation, 18.75 and 20.09 nmol/g in the stable of formation. Removal of ammonia nitrogen with concentration among 1.0-2.0 mg/L using biological-raw sands and biological-iron oxide coated sands were 92% to 95% in the initial of formation, In the stable of formation, removal ammonia nitrogen using biological-raw sands stable about 60%, and removal ammonia nitrogen using biological-iron oxide coated sands stable about 80%. In different concentrations of ammonia nitrogen among 0.5~4.0 mg/L, removal efficiency of biological-raw sands from 60% rose to 80%, biological- iron oxide coated sands from 70% rose to

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

    DEFF Research Database (Denmark)

    Arpanaei, Ayyoob; Winther-Jensen, Bjørn; Theodosiou, E.

    2010-01-01

    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...... 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...

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

    KAUST Repository

    Chakraborty, Anutosh

    2009-07-07

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

  9. Effect of Adsorbent Diameter on the Performance of Adsorption Refrigeration

    Institute of Scientific and Technical Information of China (English)

    黄宏宇; 何兆红; 袁浩然; 小林敬幸; 赵丹丹; 窪田光宏; 郭华芳

    2014-01-01

    Adsorbents are important components in adsorption refrigeration. The diameter of an adsorbent can af-fect the heat and mass transfer of an adsorber. The effect of particle diameter on effective thermal conductivity was investigated. The heat transfer coefficient of the refrigerant and the void rate of the adsorbent layer can also affect the effective thermal conductivity of adsorbents. The performance of mass transfer in the adsorber is better when pressure drop decreases. Pressure drop decreases with increasing permeability. The permeability of the adsorbent layer can be improved with increasing adsorbent diameter. The effect of adsorbent diameter on refrigeration output power was experimentally studied. Output power initially increases and then decreases with increasing diameter under different cycle time conditions. Output power increases with decreasing cycle time under similar diameters.

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

    Science.gov (United States)

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

    1988-01-01

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

  11. Radon emanation from radium specific adsorbents.

    Science.gov (United States)

    Alabdula'aly, Abdulrahman I; Maghrawy, Hamed B

    2010-01-01

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

  12. Linear Sweep Voltammetry of Adsorbed Neutral Red.

    Science.gov (United States)

    1982-05-01

    E. Creager, G. T. Marks, D. A. Aikens and H. H. Richtol Prepared for Publication in Journal of Electroanalytical Chemistry Rensselaer Polytechnic... Electroanalytical Chemistry It. KEY WORDS (Continue oun reverse side It necessary mid Ideneliy by block ntaibor) Neutral Red, cyclic voltammetry, adsorbed dye 20

  13. Adsorbate Diffusion on Transition Metal Nanoparticles

    Science.gov (United States)

    2015-01-01

    catalysis . KEYWORDS: Heterogeneous catalysis , diffusion, edge barrier, transition metal nanoparticles, DFT calculations 2 Diffusion of adsorbed...species on transition metal surfaces is an important process for thin-film and nanostructure growth and for heterogeneous catalysis , among others.1-4 In...process for heterogeneously catalyzed reactions, and as a result, an atomistic understanding of the diffusion mechanism is very important. We

  14. Heparin interaction with protein-adsorbed surfaces

    NARCIS (Netherlands)

    Winterton, Lynn C.; Andrade, Joseph D.; Feijen, Jan; Kim, Sung Wan

    1986-01-01

    Albumin and fibrinogen show no binding affinity to varied molecular weights of heparin at physiological pH. Human plasma fibronectin was shown to bind heparins in both the solution and adsorbed states. Fibronectin was shown to have six active binding sites for heparins which may be sterically blocke

  15. Facile synthesis of MWCNT/SiO2 nano-composites as high-performance oil adsorbents%多壁碳纳米管/二氧化硅纳米复合材料的制备及其吸油性能

    Institute of Scientific and Technical Information of China (English)

    黄剑坤; 刘会娥; 黄扬帆; 马雁冰; 丁传芹

    2016-01-01

    以羧化多壁碳纳米管为基体、纳米硅溶胶粒为增强相,通过一步液相共混方法制备多壁碳纳米管/二氧化硅纳米复合材料。利用傅里叶变换红外光谱(FTIR)、电子扫描电镜(SEM)、热重(TGA)、孔结构分析(BET/BJH)对其进行了表征。以水中柴油为研究对象考察了该样品对水中柴油的吸附脱除效果,并与纳米二氧化硅胶粒、原生碳纳米管以及活性炭进行对比。结果表明:硅溶胶粒表面修饰后的多壁碳纳米管的聚团行为得以改善,而且材料具有微孔-介孔双孔道结构。对水中直馏柴油的去除率高达97.79%,并于1 h达到吸附平衡。整个吸附过程遵循准二级动力学模型,吸附体系的表观活化能为11.37 kJ·mol−1,吸附等温线与Freundlich模型较为吻合,吸附效果明显强于其他3种吸附剂。%Multi-walled carbon nanotubes-silica (MWCNT/SiO2)nano-composites were prepared from carboxylated MWCNTs and silica sol-gel nanoparticlesvia one-step scalable precipitation. Structure and physical properties of the nano-composite were characterized by Fourier transform infrared spectroscopy (FTIR), scanning electron microscope (SEM), thermogravimetric analysis (TGA), and porous surface area and pore size distribution analysis (BET & BJH). Adsorption removal of oil was evaluated in diesel water on the nano-composite in comparison with SiO2 sol-gel nanoparticles, pristine MWCNTs, and activated carbon. The nano-composite improved MWCNT agglomeration after surface modification by silica nanoparticles and formed dual microporous and mesoporous structures. The diesel removal efficiency of the nano-compositecould be up to 97.79% with adsorption equilibrium reached within 1 h. The adsorption process followed the pseudo second-order kinetics with the apparent activation energy at 11.37 kJ·mol−1 and the adsorption isotherms were fitted well with the Freundlich model. Overall, the nano-composite

  16. Effect of biofouling on the performance of amidoxime-based polymeric uranium adsorbents

    Energy Technology Data Exchange (ETDEWEB)

    Park, Jiyeon; Gill, Gary A.; Strivens, Jonathan E.; Kuo, Li-Jung; Jeters, Robert T.; Avila, Andrew; Wood, Jordana R.; Schlafer, Nicholas J.; Janke, Christopher J.; Miller, Erin A.; Thomas, Mathew; Addleman, Raymond S.; Bonheyo, George T.

    2016-01-27

    The Marine Science Laboratory at the Pacific Northwest National Laboratory evaluated the impact of biofouling on uranium adsorbent performance. A surface modified polyethylene adsorbent fiber provided by Oak Ridge National Laboratory, AF adsorbent, was tested either in the presence or absence of light to simulate deployment in shallow or deep marine environments. 42-day exposure tests in column and flume settings showed decreased uranium uptake by biofouling. Uranium uptake was reduced by up to 30 %, in the presence of simulated sunlight, which also increased biomass accumulation and altered the microbial community composition on the fibers. These results suggest that deployment below the photic zone would mitigate the effects of biofouling, resulting in greater yields of uranium extracted from seawater.

  17. Waste metal hydroxide sludge as adsorbent for a reactive dye.

    Science.gov (United States)

    Santos, Sílvia C R; Vílar, Vítor J P; Boaventura, Rui A R

    2008-05-30

    An industrial waste sludge mainly composed by metal hydroxides was used as a low-cost adsorbent for removing a reactive textile dye (Remazol Brilliant Blue) in solution. Characterization of this waste material included chemical composition, pH(ZPC) determination, particle size distribution, physical textural properties and metals mobility under different pH conditions. Dye adsorption equilibrium isotherms were determined at 25 and 35 degrees C and pH of 4, 7 and 10 revealing reasonably fits to Langmuir and Freundlich models. At 25 degrees C and pH 7, Langmuir fit indicates a maximum adsorption capacity of 91.0mg/g. An adsorptive ion-exchange mechanism was identified from desorption studies. Batch kinetic experiments were also conducted at different initial dye concentration, temperature, adsorbent dosage and pH. A pseudo-second-order model showed good agreement with experimental data. LDF approximation model was used to estimate homogeneous solid diffusion coefficients and the effective pore diffusivities. Additionally, a simulated real effluent containing the selected dye, salts and dyeing auxiliary chemicals, was also used in equilibrium and kinetic experiments and the adsorption performance was compared with aqueous dye solutions.

  18. Sustainable conversion of agro-wastes into useful adsorbents

    Science.gov (United States)

    Bello, Olugbenga Solomon; Owojuyigbe, Emmanuel Seun; Babatunde, Monsurat Abiodun; Folaranmi, Folasayo Eunice

    2016-11-01

    Preparation and characterization of raw and activated carbon derived from three different selected agricultural wastes: kola nut pod raw and activated (KNPR and KNPA), bean husk raw and activated (BHR and BHA) and coconut husk raw and activated (CHR and CHA) were investigated, respectively. Influences of carbonization and acid activation on the activated carbon were investigated using SEM, FTIR, EDX, pHpzc and Boehm titration techniques, respectively. Carbonization was done at 350 °C for 2 h followed by activation with 0.3 M H3PO4 (ortho-phosphoric acid). Results obtained from SEM, FTIR, and EDX revealed that, carbonization followed by acid activation had a significant influence on morphology and elemental composition of the samples. SEM showed well-developed pores on the surface of the precursors after acid treatment, FTIR spectra revealed reduction, broadening, disappearance or appearance of new peaks after acid activation. EDX results showed highest percentage of carbon by atom respectively in the order BHA > KNPA > CHA respectively. The pHpzc was found to be 5.32, 4.57 and 3.69 for KNPA, BHA and CHA, respectively. Boehm titration result compliments that of pHpzc, indicating that the surfaces of the prepared adsorbents are predominantly acidic. This study promotes a sustainable innovative use of agro-wastes in the production of cheap and readily available activated carbons, thereby ensuring more affordable water and effluent treatment adsorbents.

  19. Nitric oxide adsorbed on zeolites: EPR studies.

    Science.gov (United States)

    Yahiro, Hidenori; Lund, Anders; Shiotani, Masaru

    2004-05-01

    CW-EPR studies of NO adsorbed on sodium ion-exchanged zeolites were focused on the geometrical structure of NO monoradical and (NO)2 biradical formed on zeolites. The EPR spectrum of NO monoradical adsorbed on zeolite can be characterized by the three different g-tensor components and the resolved y-component hyperfine coupling with the 14N nucleus. Among the g-tensor components, the value of g(zz) is very sensitive to the local environment of zeolite and becomes a measure of the electrostatic field in zeolite. The temperature dependence of the g-tensor demonstrated the presence of two states of the Na-NO adduct, in rigid and rotational states. The EPR spectra of NO adsorbed on alkaline metal ion-exchanged zeolite and their temperature dependency are essentially the same as that on sodium ion-exchanged zeolite. On the other hand, for NO adsorbed on copper ion-exchanged zeolite it is known that the magnetic interaction between NO molecule and paramagnetic copper ion are observable in the spectra recorded at low temperature. The signals assigned to (NO)2 biradical were detected for EPR spectrum of NO adsorbed on Na-LTA. CW-EPR spectra as well as their theoretical calculation suggested that the two NO molecules are aligned along their N-O bond axes. A new procedure for automatical EPR simulation is described which makes it possible to analyze EPR spectrum easily. In the last part of this paper, some instances when other nitrogen oxides were used as a probe molecule to characterize the zeolite structure, chemical properties of zeolites, and dynamics of small molecules were described on the basis of selected literature data reported recently.

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

    DEFF Research Database (Denmark)

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

    1998-01-01

    Using density functional theory we study the effect of pre-adsorbed atoms on the dissociation of N(2) and the adsorption of N, N(2), and CO on Ru(0001). We have done calculations for pre-adsorbed Na, Cs, and S, and find that alkali atoms adsorbed close to a dissociating N(2) molecule will lower...... the barrier for dissociation, whereas S will increase it. The interaction with alkali atoms is mainly of an electrostatic nature. The poisoning by S is due to two kinds of repulsive interactions: a Pauli repulsion and a reduced covalent bond strength between the adsorbate and the surface d-electrons. In order...... to investigate these different interactions in more detail, we look at three different species (N atoms, and terminally bonded N(2) and CO) and use them as probes to study their interaction with two modifier atoms (Na and S). The two modifier atoms have very different properties, which allows us to decouple...

  1. 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.

  2. Carrier-dependent magnetic anisotropy of Gd-adsorbed graphene

    Science.gov (United States)

    Lu, Yuan; Zhou, Tie-ge; Shao, Bin; Zuo, Xu; Feng, Min

    2016-05-01

    Using first-principles calculation based on density functional theory, we study the magnetic anisotropy of Gd-adsorbed graphene and its dependence on carrier accumulation. We show that carrier accumulation not only impacts the magnitude of magnetic anisotropy but also switches its sign. Hole accumulation enhances the perpendicular anisotropy up to ˜16 meV per Gd atom, while electron accumulation switches the anisotropy from perpendicular to in-plane direction. Moreover, we find that the first order perturbation of spin-orbit coupling interaction induces a pseudo-gap at Γ for the perpendicular magnetization, which leads to the the anomalous magnetic anisotropy for the neutral composite. Our findings pave the way for magneto-electric materials based on rare-earth-decorated graphene for voltage-controlled spintronics.

  3. Carrier-dependent magnetic anisotropy of Gd-adsorbed graphene

    Directory of Open Access Journals (Sweden)

    Yuan Lu

    2016-05-01

    Full Text Available Using first-principles calculation based on density functional theory, we study the magnetic anisotropy of Gd-adsorbed graphene and its dependence on carrier accumulation. We show that carrier accumulation not only impacts the magnitude of magnetic anisotropy but also switches its sign. Hole accumulation enhances the perpendicular anisotropy up to ∼16 meV per Gd atom, while electron accumulation switches the anisotropy from perpendicular to in-plane direction. Moreover, we find that the first order perturbation of spin-orbit coupling interaction induces a pseudo-gap at Γ for the perpendicular magnetization, which leads to the the anomalous magnetic anisotropy for the neutral composite. Our findings pave the way for magneto-electric materials based on rare-earth-decorated graphene for voltage-controlled spintronics.

  4. Investigation on Adsorption State of Surface Adsorbate on Silicon Wafer

    Institute of Scientific and Technical Information of China (English)

    1999-01-01

    An adsorption kinetics model for adsorbate on the specularly polished silicon wafer was suggested. The mathematical model of preferential adsorption and the mechanism controlling the adsorption state of adsorbate were discussed.

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

    Science.gov (United States)

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

    2011-09-01

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

  6. 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.

  7. Analysis of Adsorbed Natural Gas Tank Technology

    Science.gov (United States)

    Knight, Ernest; Schultz, Conrad; Rash, Tyler; Dohnke, Elmar; Stalla, David; Gillespie, Andrew; Sweany, Mark; Seydel, Florian; Pfeifer, Peter

    With gasoline being an ever decreasing finite resource and with the desire to reduce humanity's carbon footprint, there has been an increasing focus on innovation of alternative fuel sources. Natural gas burns cleaner, is more abundant, and conforms to modern engines. However, storing compressed natural gas (CNG) requires large, heavy gas cylinders, which limits space and fuel efficiency. Adsorbed natural gas (ANG) technology allows for much greater fuel storage capacity and the ability to store the gas at a much lower pressure. Thus, ANG tanks are much more flexible in terms of their size, shape, and weight. Our ANG tank employs monolithic nanoporous activated carbon as its adsorbent material. Several different configurations of this Flat Panel Tank Assembly (FPTA) along with a Fuel Extraction System (FES) were examined to compare with the mass flow rate demands of an engine.

  8. Fluorescence of dyes adsorbed on highly organized nanostructured gold surfaces

    NARCIS (Netherlands)

    Levi, Stefano A.; Mourran, Ahmed; Spatz, Joachim P.; Veggel, van Frank C.J.M.; Reinhoudt, David N.; Möller, M.

    2002-01-01

    It is shown that fluorescent dyes can be adsorbed selectively on gold nanoparticles which are immobilized on a glass substrate and that the fluorescence originating from the adsorbed dyes exhibits significantly less quenching when compared to dyes adsorbed on bulk gold. Self-assembled monolayers of

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2015-09-30

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

  10. Behavior of macromolecules in adsorbed layers

    Institute of Scientific and Technical Information of China (English)

    牟伯中[1; 姚恒申[2; 罗平亚[3

    2000-01-01

    A model for describing the behavior ot macromoiecuies in aosoroea layers is developed by introducing a concept of distribution density of layer thickness U based on stochastic process and probabilistic statistics. The molecular behavior of layers adsorbed on clay particle surfaces is discussed; the random distribution and its statistics of the layer thickness are given by incorporating experimental results with an ionic polyelectrolyte with the molecular weight of 1.08×106and chain charged density of 0.254.

  11. MOLECULAR IMPRINTED POLYMERS--Novel Polymer Adsorbents

    Institute of Scientific and Technical Information of China (English)

    LI Haitao; XU Mancai; SHI Zuoqing; HE Binglin

    2001-01-01

    Molecular imprinted polymers (MIPs) are novel functional polymer materials and known as specific adsorbents for the template molecules. These novel functional polymers have promised potential applications in racemic resolution, sensor, chromatography, adsorptive separation and other fields. This review exhibits the approach for preparing MIPs, the features of MIPs obtained by different routes and the characteristics of adsorptive separations with MIPs. The molecular recognition mechanism and the idea of the present possibilities and limitations of molecular imprinting polymerization are discussed as well.

  12. Effective Thermal Conductivity of Adsorbent Packed Beds

    Science.gov (United States)

    Mori, Hideo; Hamamoto, Yoshinori; Yoshida, Suguru

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

  13. Remediation of AMD using industrial waste adsorbents

    Science.gov (United States)

    Mohammed, Nuur Hani Bte; Yaacob, Wan Zuhairi Wan

    2016-11-01

    The study investigates the characteristic of industrial waste as adsorbents and its potential as heavy metals absorbents in AMD samples. The AMD sample was collected from active mine pond and the pH was measured in situ. The metal contents were analyzed by ICP-MS. The AMD water was very acidic (pH< 3.5), and the average heavy metals content in AMD were high especially in Fe (822.029 mg/l). Fly ash was found to be the most effective absorbent material containing high percentage of CaO (57.24%) and SiO2 (13.88%), followed by ladle furnace slag containing of high amount of CaO (51.52%) and Al2O3 (21.23%), while biomass ash consists of SiO2 (43.07%) and CaO (12.97%). Tank analysis display a huge changes due to pH value change from acidity to nearly neutral phases. After 50 days, fly ash remediation successfully increase the AMD pH values from pH 2.57-7.09, while slag change from acidity to nearly alkaline phase from pH 2.60-7.3 and biomass has change to pH 2.54-6.8. Fly ash has successfully remove Fe, Mn, Cu, and Ni. Meanwhile, slag sample displays as an effective adsorbent to adsorb more Pb and Cd in acid mine drainage.

  14. 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

    :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.

  15. The Uranium from Seawater Program at the Pacific Northwest National Laboratory: Overview of Marine Testing, Adsorbent Characterization, Adsorbent Durability, Adsorbent Toxicity, and Deployment Studies

    Energy Technology Data Exchange (ETDEWEB)

    Gill, Gary A.; Kuo, Li-Jung; Janke, Chris J.; Park, Jiyeon; Jeters, Robert T.; Bonheyo, George T.; Pan, Horng-Bin; Wai, Chien; Khangaonkar, Tarang; Bianucci, Laura; Wood, Jordana R.; Warner, Marvin G.; Peterson, Sonja; Abrecht, David G.; Mayes, Richard T.; Tsouris, Costas; Oyola, Yatsandra; Strivens, Jonathan E.; Schlafer, Nicholas J.; Addleman, R. Shane; Chouyyok, Wilaiwan; Das, Sadananda; Kim, Jungseung; Buesseler, Ken; Breier, Crystal; D’Alessandro, Evan

    2016-02-07

    The Pacific Northwest National Laboratory’s (PNNL) Marine Science Laboratory (MSL) located along the coast of Washington State is evaluating the performance of uranium adsorption materials being developed for seawater extraction under realistic marine conditions with natural seawater. Two types of exposure systems were employed in this program: flow-through columns for testing of fixed beds of individual fibers and pellets and a recirculating water flume for testing of braided adsorbent material. Testing consists of measurements of the adsorption of uranium and other elements from seawater as a function of time, typically 42 to 56 day exposures, to determine the adsorbent capacity and adsorption rate (kinetics). Analysis of uranium and other trace elements collected by the adsorbents was conducted following strong acid digestion of the adsorbent with 50% aqua regia using either Inductively Coupled Plasma Optical Emission Spectrometry (ICP-OES) or Inductively Coupled Plasma Mass Spectrometer (ICP-MS). The ORNL 38H adsorbent had a 56 day adsorption capacity of 3.30 ± 0.68 g U/ kg adsorbent (normalized to a salinity of 35 psu), a saturation adsorption capacity of 4.89 ± 0.83 g U/kg of adsorbent material (normalized to a salinity of 35 psu) and a half-saturation time of 28 ± 10 days. The AF1 adsorbent material had a 56 day adsorption capacity of 3.9 ± 0.2 g U/kg adsorbent material (normalized to a salinity of 35 psu), a saturation capacity of 5.4 ± 0.2 g U/kg adsorbent material (normalized to a salinity of 35 psu) and a half saturation time of 23 ± 2 days. The ORNL amidoxime-based adsorbent materials are not specific for uranium, but also adsorb other elements from seawater. The major doubly charged cations in seawater (Ca and Mg) account for a majority of the cations adsorbed (61% by mass and 74% by molar percent). For the ORNL AF1 adsorbent material, U is the 4th most abundant element adsorbed by mass and 7th most abundant by molar percentage

  16. MOLECULAR IMPRINTED POLYMERS—Novel Polymer Adsorbents

    Institute of Scientific and Technical Information of China (English)

    LIHaitao; XUMancai; 等

    2001-01-01

    Molecular imprinted polymers(MIPs) are novel functional polymer materials and known as specific adsorbents for the template molecules,These novel functional polymers have promised potential applications in racemic resolution,sensor,chromatography,adsorptive separation and other fields.This review exhibits the approach for preparing MIPs,the features of MIPs obtained by different routes and the characteristics of adsorptive separations with MIPs.The molecular recognition mechanism and the idea of the present possibilities and limitations of molecular imprinting polymerization are discussed as well.

  17. Adsorption characteristics of water vapor on honeycomb adsorbents

    Science.gov (United States)

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

    2011-10-01

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

  18. Influence of superconductor film composition on adhesion strength of coated conductors

    Energy Technology Data Exchange (ETDEWEB)

    Kesgin, Ibrahim; Khatri, Narayan; Liu, Yuhao; Delgado, Louis; Galstyan, Eduard; Selvamanickam, Venkat

    2015-11-20

    The effect of high temperature superconductor (HTS) film composition on the adhesion strength of rare- earth barium copper oxide coated conductors (CCs) has been studied. It has been found that the mechanical integrity of the superconductor layer is very susceptible to the defects especially those along the ab plane, probably due to the weak interfaces between the defects and the matrix. Gd and Y in the standard composition were substituted with Sm and the number of in-plane defects was drastically reduced. Consequently, a four-fold increase in adhesion or peeling strength in Sm-based CCs was achieved compared to the standard GdYBCO samples.

  19. Magnetic carboxylated cellulose nanocrystals as adsorbent for the removal of Pb(II) from aqueous solution.

    Science.gov (United States)

    Lu, Jiao; Jin, Ru-Na; Liu, Chao; Wang, Yan-Fei; Ouyang, Xiao-Kun

    2016-12-01

    A novel magnetic carboxylated cellulose nanocrystal composite (CCN-Fe3O4) was prepared as an adsorbent for the adsorption of Pb(II) from aqueous solution. The new adsorbent was characterized by transmission electron microscopy, vibrating sample magnetometry, Fourier-transform infrared spectroscopy, and X-ray photoelectron spectroscopy. Batch experiments were carried out to investigate the effects of contact time, adsorbent dose, pH, and temperature on adsorption capacity. Pb(II) adsorption onto CCN-Fe3O4 reached equilibrium in 240min, and the maximum adsorption capacity of Pb(II) was 63.78mgg(-1) at 298.2K. The equilibrium data fitted the Langmuir isotherm model better than the Freundlich isotherm model, and they were well explained in terms of pseudo-second-order kinetics. Thermodynamics studies indicated that the adsorption of Pb(II) onto CCN-Fe3O4 was spontaneous and endothermic in nature. The adsorbent could also be regenerated with acid treatment and successfully reapplied.

  20. From MDF and PB wastes to adsorbents for the removal of pollutants

    Science.gov (United States)

    Gomes, J. A. F. L.; Azaruja, B. A.; Mourão, P. A. M.

    2016-09-01

    The production of activated carbons in powder and monolith forms, by physical activation with CO2, with specific surface areas between 804 and 1469 m2 g-1, porous volume between 0.33 and 0.59 cm3 g-1, with basic nature (PZC ∼ 9.6-10.6) was achieved in our lab, from medium density fibreboard (MDF) and particleboard (PB), engineered wood composites wastes. These highly porous adsorbents were applied in kinetic and equilibrium adsorption studies, in batch and dynamic modes, in powder and monolith forms, of specific adsorptives, considered pollutants, namely phenol (P), p-nitrophenol (PNP) and neutral red (NR). In batch the maximum adsorbed amount was 267, 162 and 92 mg g-1, for PNP, P and NR, respectively. The application of different kinetic models (pseudo-first order, pseudo-second order and intraparticle diffusion model) leads to a better knowledge of the adsorption mechanisms of those adsorptives. The results obtained in the kinetic and equilibrium tests show that the combination of the structural features and the surface chemistry nature of the adsorbents, with the adsorptives properties, establish the kinetic performance, the type and amount adsorbed for each system. This work confirms the potential of these types of wastes in the production of activated carbons and its application in adsorption from liquid phase.

  1. 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.

  2. An NMR study of adsorbed helium films

    Science.gov (United States)

    Kent, Anthony Joseph

    The properties of sub-monolayer Helium-3 films adsorbed on two totally different but planar substrates, Mylar† film and exfoliated graphite have been studied using NMR. The nuclear magnetic relaxation times T1 and T 2 have been measured as functions of fractional monolayer completion, temperature, substrate plane orientation and Larmor frequency using a specially designed and constructed NMR spectrometer system. The results obtained with a Mylar film substrate are consistent3with the formation of patches of solid 3He at regions of preferential adsorption on the substrate. Measurements of T2 m very low coverage 3He films on exfoliated graphite also indicate that the adsorbate forms areas of relatively high density solid, in agreement with the thermodynamic analysis of Elgin and Goodstein. Finally, detailed measurements of T2 as a function of all of the above parameters at low areal densities will help us to characterise the relaxation processes for the fluid phase of 33He on exfoliated graphite. †Mylar is the tradename of poly(ethelene-terephthalate) film, marketed by Du Pont.

  3. Dye sequestration using agricultural wastes as adsorbents

    Directory of Open Access Journals (Sweden)

    Kayode Adesina Adegoke

    2015-12-01

    Full Text Available Color is a visible pollutant and the presence of even minute amounts of coloring substance makes it undesirable due to its appearance. The removal of color from dye-bearing effluents is a major problem due to the difficulty in treating such wastewaters by conventional treatment methods. The most commonly used methods for color removal are biological oxidation and chemical precipitation. However, these processes are effective and economic only in the case where the solute concentrations are relatively high. Most industries use dyes and pigments to color their products. The presence of dyes in effluents is a major concern due to its adverse effect on various forms of life. The discharge of dyes in the environment is a matter of concern for both toxicological and esthetical reasons. It is evident from a literature survey of about 283 recently published papers that low-cost adsorbents have demonstrated outstanding removal capabilities for dye removal and the optimal equilibrium time of various dyes with different charcoal adsorbents from agricultural residues is between 4 and 5 h. Maximum adsorptions of acidic dyes were obtained from the solutions with pH 8–10. The challenges and future prospects are discussed to provide a better framework for a safer and cleaner environment.

  4. Optimizing heterosurface adsorbent synthesis for liquid chromatography

    Science.gov (United States)

    Bogoslovskii, S. Yu.; Serdan, A. A.

    2016-03-01

    The structural and geometric parameters of a silica matrix (SM) for the synthesis of heterosurface adsorbents (HAs) are optimized. Modification is performed by shielding the external surfaces of alkyl-modified silica (AS) using human serum albumin and its subsequent crosslinking. The structural and geometric characteristics of the SM, AS, and HA are measured via low-temperature nitrogen adsorption. It is found that the structural characteristics of AS pores with diameters D 9 nm reduces significantly due to adsorption of albumin. It is concluded that silica gel with a maximum pore size distribution close to 5 nm and a minimal proportion of pores with D > 9 nm is optimal for HA synthesis; this allows us to achieve the greatest similarity between the chromatographic retention parameters for HA and AS. The suitability of the synthesized adsorbents for analyzing drugs in biological fluids through direct sample injection is confirmed by chromatography. It was found that the percentage of the protein fraction detected at the outlet of the chromatographic column is 98%.

  5. TRMM project contamination control using molecular adsorbers

    Energy Technology Data Exchange (ETDEWEB)

    Straka, S.; Chen, P.; Thomson, S. [NASA Goddard Space Flight Center, Greenbelt, Maryland 20771 (United States); Bettini, R.; Triolo, J.; Carosso, N. [Swales and Associates, Inc., 5050 Powder Mill Road, Beltsville, Maryland 20705 (United States)

    1996-03-01

    The Tropical Rainfall Measuring Mission (TRMM) is a spacecraft under development by the National Aeronautics and Space Administration (NASA) and the National Space Development Agency of Japan (NASDA) and is scheduled for launch in August 1997. The spacecraft design includes the use of numerous optical instruments and the thermal control surfaces. In addition to the inherent contamination sensitivities of the optical and thermal systems, TRMM has had the added challenge of designing systems to function at a relatively low altitude (350 km), with solar exposure. Under these conditions, high atomic oxygen densities and potentially high levels of backscattered contamination (self-contamination), as well as UV photopolymerization effects, all pose major threats to sensitive TRMM elements. In considering the various contamination control paths to follow, the TRMM project management has opted for pursuing a relatively new, but very promising technology for the TRMM spacecraft in order to lower the on-orbit contamination levels. TRMM will be incorporating Molecular Adsorbers as part of the basic spacecraft design. This paper will summarize the TRMM requirements, describe the Molecular Adsorbers being fabricated for the mission, and discuss the expected benefits of this method of on-orbit contamination control. {copyright} {ital 1996 American Institute of Physics.}

  6. Equilibrium molecular theory of two-dimensional adsorbate drops on surfaces of heterogeneous adsorbents

    Science.gov (United States)

    Tovbin, Yu. K.

    2016-08-01

    A molecular statistical theory for calculating the linear tension of small multicomponent droplets in two-dimensional adsorption systems is developed. The theory describes discrete distributions of molecules in space (on a scale comparable to molecular size) and continuous distributions of molecules (at short distances inside cells) in their translational and vibrational motions. Pair intermolecular interaction potentials (the Mie type potential) in several coordination spheres are considered. For simplicity, it is assumed that distinctions in the sizes of mixture components are slight and comparable to the sizes of adsorbent adsorption centers. Expressions for the pressure tensor components inside small droplets on the heterogeneous surface of an adsorbent are obtained, allowing calculations of the thermodynamic characteristics of a vapor-fluid interface, including linear tension. Problems in refining the molecular theory are discussed: describing the properties of small droplets using a coordination model of their structure, considering the effect an adsorbate has on the state of a near-surface adsorbent region, and the surface heterogeneity factor in the conditions for the formation of droplets.

  7. Constructing a proton titration curve from ion-step measurements, applied to a membrane with adsorbed protein

    NARCIS (Netherlands)

    Eijkel, Jan C.T.; Bosch, Coen; Olthuis, Wouter; Bergveld, Piet

    1997-01-01

    A new measuring method is described for obtaining a proton titration curve. The curve is obtained from a microporous composite membrane, consisting of polystyrene beads in an agarose matrix, with lysozyme molecules adsorbed to the bead surface. The membrane is incorporated into a sensor system by de

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2015-09-30

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

  9. DESORPTION OF VOCs FROM POLYMERIC ADSORBENTS UNDER MICROWAVE FIELD

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    Desorption of volatile organic compounds (VOCs)from polymeric adsorbents by microwave was investigated experimentally. Two kinds of organic compounds, benzene and toluene,were separately used as adsorbates in this work. Results showed that the application of microwave to regenerate the polymeric adsorbents not only can get higher regeneration efficiency in comparison with the use of heat regeneration, but also make the temperatures of the fixed beds much lower than that when using the heat regeneratton The weaker the polarity of a polymeric adsorbent, the easier its regeneration was.

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

    KAUST Repository

    Chakraborty, Anutosh

    2009-02-17

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

  11. Carbon Dioxide Capture Adsorbents: Chemistry and Methods.

    Science.gov (United States)

    Patel, Hasmukh A; Byun, Jeehye; Yavuz, Cafer T

    2016-12-21

    Excess carbon dioxide (CO2 ) emissions and their inevitable consequences continue to stimulate hard debate and awareness in both academic and public spaces, despite the widespread lack of understanding on what really is needed to capture and store the unwanted CO2 . Of the entire carbon capture and storage (CCS) operation, capture is the most costly process, consisting of nearly 70 % of the price tag. In this tutorial review, CO2 capture science and technology based on adsorbents are described and evaluated in the context of chemistry and methods, after briefly introducing the current status of CO2 emissions. An effective sorbent design is suggested, whereby six checkpoints are expected to be met: cost, capacity, selectivity, stability, recyclability, and fast kinetics.

  12. The condensation of water on adsorbed viruses.

    Science.gov (United States)

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

    2013-11-26

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

  13. Trends in adsorbate induced core level shifts

    Science.gov (United States)

    Nilsson, Viktor; Van den Bossche, Maxime; Hellman, Anders; Grönbeck, Henrik

    2015-10-01

    Photoelectron core level spectroscopy is commonly used to monitor atomic and molecular adsorption on metal surfaces. As changes in the electron binding energies are convoluted measures with different origins, calculations are often used to facilitate the decoding of experimental signatures. The interpretation could in this sense benefit from knowledge on trends in surface core level shifts for different metals and adsorbates. Here, density functional theory calculations have been used to systematically evaluate core level shifts for (111) and (100) surfaces of 3d, 4d, and 5d transition metals upon CO, H, O and S adsorption. The results reveal trends and several non-intuitive cases. Moreover, the difficulties correlating core level shifts with charging and d-band shifts are underlined.

  14. Preparation and characterization of adsorbents for treatment of water associated with oil production

    KAUST Repository

    Sueyoshi, Mark

    2012-09-01

    Two sets of adsorbents were prepared from locally available raw materials, characterized and tested. The first set consists of crushed natural attapulgite and crushed attapulgite mixed with petroleum tank-bottom sludge and carbonized at 650 °C. Another set was prepared using trunk of date palm tree (Phoenix dactylifera) activated at 700 and 800°C. Both sets were characterized using BET surface area and pore distributions, FTIR, XRD, SEM and TEM. Natural attapulgite and attapulgite/sludge composite exhibited different characteristics and adsorptive capacities for oil removal from oily water. Adsorptive capacities were calculated from the breakthrough curves of a column test. An oily water solution of about 500 mg-oil/L was passed through both the attapulgite and attapulgite/sludge columns until the column effluent concentration exceeded a reference limit of 10 mg-oil/L. Uptake was calculated at this limit at 155 and 405 mg-oil/g-adsorbent, respectively. This was lower than the performance of a commercial activated carbon sample (uptake calculated at 730 mg-oil/g-adsorbent). Relatively, the date palm, carbonaceous-based adsorbent samples showed less significant differences in both bulk and surface properties. Uptake significantly improved to 1330-1425 mg-oil/g-adsorbent. Attempt was made to associate this performance with the difference in the surface areas between the two sets. However, other factors are found to be important as the second set has a range of surface area less than that of the commercial sample. As evidenced by FTIR, XRD and TEM, the activated carbonaceous materials developed porous structures which form defective graphitic sheet ensembles that serve as additional adsorption sites in the sample. © 2012 Elsevier B.V.

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

    Directory of Open Access Journals (Sweden)

    Deepak H Veeregowda

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

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

    DEFF Research Database (Denmark)

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

    2010-01-01

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

  17. Single bank NOx adsorber for heavy duty diesel engines

    NARCIS (Netherlands)

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

    2003-01-01

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

  18. Friction and diffusion dynamics of adsorbates at surfaces

    NARCIS (Netherlands)

    Fusco, C.

    2005-01-01

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

  19. Selective sorption of perfluorooctane sulfonate on molecularly imprinted polymer adsorbents

    Institute of Scientific and Technical Information of China (English)

    Shubo DENG; Danmeng SHUAI; Qiang YU; Jun HUANG; Gang YU

    2009-01-01

    Perfluorooctane sulfonate (PFOS), as a potential persistent organic pollutant, has been widely detected in water environments, and has become a great concern in recent years. PFOS is very stable and difficult to decompose using conventional techniques. Sorption may be an attractive method to remove it from water. In this study, the molecularly imprinted polymer (MIP) adsorbents were prepared through the polymerization of 4-vinylpyridine under different preparation conditions in order to remove perfluorooctane sulfonate (PFOS) from water. The MIP adsorbents using perfluorooctanoic acid (PFOA) as the template had good imprinting effects and could selectively remove PFOS from aqueous solution. The sorption behaviors including sorption kinetics,isotherms, and effect of pH, salt, and competitive anions were investigated. Experimental results showed that the sorption of PFOS On the MIP adsorbents was very fast, pH-dependent, and highly selective. The achieved fast sorption equilibrium within 1 h was attributed to the surface sorption on the fine adsorbents. The sorption isotherms showed that the sorption selectivity of PFOS on the MIP adsorbents decreased at high PFOS concentrations, which may be due to the double-layer sorption and the formation of PFOS micelles on the sorbent surface. The sorption of PFOS on the MIP adsorbents was mainly dominated by the electrostatic interaction between the protonated vinylpyridine on the adsorbent surface and the anionic PFOS. The prepared MIP adsorbents can potentially be applied in water and wastewater treatment for selective removal of PFOS.

  20. Mixed-matrix membrane adsorbers for protein separation

    NARCIS (Netherlands)

    Avramescu, Maria-Elena; Borneman, Zandrie; Wessling, Matthias

    2003-01-01

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

  1. Adsorbent Carbon Fabrics : New Generation Armour for Toxic Chemicals

    Directory of Open Access Journals (Sweden)

    K. Gurudatt

    1997-04-01

    Full Text Available Activated carbon in the form of a regular fabric obtained using viscose rayon precursor is a new generation adsorbent material having superior sorptional properties and is finding varied defence applications. Carbonisation and activation mechanisms and properties and applications of adsorbent carbort fibres made from viscose rayon precursor are reviewed in this paper.

  2. Synergistically strengthened 3D micro-scavenger cage adsorbent for selective removal of radioactive cesium

    Science.gov (United States)

    Jang, Sung-Chan; Kang, Sung-Min; Haldorai, Yuvaraj; Giribabu, Krishnan; Lee, Go-Woon; Lee, Young-Chul; Hyun, Moon Seop; Han, Young-Kyu; Roh, Changhyun; Huh, Yun Suk

    2016-12-01

    A novel microporous three-dimensional pomegranate-like micro-scavenger cage (P-MSC) composite has been synthesized by immobilization of iron phyllosilicates clay onto a Prussian blue (PB)/alginate matrix and tested for the removal of radioactive cesium from aqueous solution. Experimental results show that the adsorption capacity increases with increasing the inactive cesium concentration from 1 ppm to 30 ppm, which may be attributed to greater number of adsorption sites and further increase in the inactive cesium concentration has no effect. The P-MSC composite exhibit maximum adsorption capacity of 108.06 mg of inactive cesium per gram of adsorbent. The adsorption isotherm is better fitted to the Freundlich model than the Langmuir model. In addition, kinetics studies show that the adsorption process is consistent with a pseudo second-order model. Furthermore, at equilibrium, the composite has an outstanding adsorption capacity of 99.24% for the radioactive cesium from aqueous solution. This may be ascribed to the fact that the AIP clay played a substantial role in protecting PB release from the P-MSC composite by cross-linking with alginate to improve the mechanical stability. Excellent adsorption capacity, easy separation, and good selectivity make the adsorbent suitable for the removal of radioactive cesium from seawater around nuclear plants and/or after nuclear accidents.

  3. Adsorption of Fluoride Ion by Inorganic Cerium Based Adsorbent

    Institute of Scientific and Technical Information of China (English)

    Jiao Zhongzhi(焦中志); Chen Zhonglin; Yang Min; Zhang Yu; Li Guibai

    2004-01-01

    Excess of fluoride in drinking water is harmful to human health, the concentration of F- ions must be maintained in the range of 0.5 to 1.5 mg/L. An inorganic cerium based adsorbent (CTA) is developed on the basis of research of adsorption of fluoride on cerium oxide hydrate. Some adsorption of fluoride by CTA adsorbent experiments were carried out, and results showed that CTA adsorbent has a quick adsorption speed and a large adsorption capacity. Adsorption follows Freundlich isotherm, and low pH value helps fluoride removal. Some physical-chemical characteristics of CTA adsorbent were experimented, fluoride removal mechanism was explored, and results showed that hydroxyl group of CTA adsorbent played an important role in the fluoride removal.

  4. Bio-regeneration of π-complexation desulfurization adsorbents

    Institute of Scientific and Technical Information of China (English)

    LI; Wangliang; XING; Jianmin; XIONG; Xiaochao; SHAN; Guob

    2005-01-01

    The coupling of adsorption desulfurization and biodesulfurization is a new approach to produce clean fuels. Sulfur compounds are firstly adsorbed on adsorbents, and then the adsorbents are regenerated by microbial conversion. π-Complexation adsorbent, Cu(Ⅰ)-Y, was obtained by ion exchanging Y-type zeolite with Cu2+ and then by auto-reduction in helium at 450℃ for 3 h. Dibenzothiophene (DBT) was used as a model compound. The effects of cell concentration, volume of oil phase, the ratio of aqueous phase to adsorbent on DBT desorption by a bacterium were studied. The amounts of DBT desorbed and 2-HBP produced can be apparently increased with addition of n-octane. BDS activity can be improved by increasing cell concentration and the ratio of water-to-adsorbent. 89% of DBT desorbed from the adsorbents can be converted to 2-HBP within 6 h and almost 100% within 24 h, when the volume ratio of oil-to-water was 1/5 mL/mL, the cell concentration was 60 g·L-1, and the ratio of adsorbent-to-oil was 0.03 g·mL-1. The amount of 2-HBP produced was strongly dependent on the volume ratio of oil-to- water, cell concentration and amount of adsorbent. Adsorption capacity of the regenerated adsorbent is 95% that of the fresh one after being desorbed with Pseudomonas delafieldii R-8, washed with n-octane, dried at 100℃ for 24 h and auto-reduced in He.

  5. Treatment with activated carbon and other adsorbents as an effective method for removal of volatile compounds in agricultural distillates.

    Science.gov (United States)

    Balcerek, Maria; Pielech-Przybylska, Katarzyna; Patelski, Piotr; Dziekońska-Kubczak, Urszula; Jusel, Tomaš

    2017-01-20

    This study investigates the effect of treatment with activated carbon and other adsorbents on the chemical composition and organoleptics of a barley malt-based agricultural distillate. Contact with activated carbon is one of the methods by which the quality of raw distillates and spirit beverages can be improved. Samples placed in contact with 1 g activated carbon (SpiritFerm) per 100 ml distillate with ethanol content of 50% v v(-1) for 1 h showed the largest reductions in the concentrations of most volatile compounds (aldehydes, alcohols, esters). Increasing the dose of adsorbent to over 1 g 100 ml(-1) did not improve the purity of the agricultural distillate significantly. Of the tested compounds, acetaldehyde and methanol showed the lowest adsorption on activated carbon. The lowest concentrations of these congeners (expressed in mg l(-1) alcohol 100% v v(-1)) were measured in solutions with ethanol contents of 70-80% v v(-1), while solutions with an alcoholic strength by volume of 40% did not show statistically significant decreases in these compounds in relation the control sample. The reductions in volatile compounds were compared with those for other adsorbents based on silica or activated carbon and silica. An interesting alternative to activated carbon was found to be an adsorbent prepared from activated carbon and silica (Spiricol). Treatment with this adsorbent produced distillate with the lowest concentrations of acetaldehyde and isovaleraldehyde, and led to the greatest improvement in its organoleptics.

  6. 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.

  7. Mercury adsorption properties of sulfur-impregnated adsorbents

    Science.gov (United States)

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

    2002-01-01

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

  8. Mechanical Behaviour of Glassy Composite Seals for IT-SOFC Application

    DEFF Research Database (Denmark)

    Nielsen, Karsten Agersted; Solvang, Mette; Nielsen, Sofie Birkedal Lund

    2007-01-01

    to thermal cycling were then investigated on selected combinations of materials after ageing. Strongest bonding between sodium aluminosilicate glass composite and steel surfaces was obtained for sealing at 850°C. For the strongest interface, having shear strength of 2.35 MPa, rupture occurred in the glass...... matrix, meaning that the glass-steel interfaces are, in this case, even stronger. Application of transition metal oxide coatings on etched surfaces of Crofer 22APU steel showed a significant improvement in the development of a seamless transition zone between metal and glass, whereas the same coatings...

  9. Novel adhesive properties of poly(ethylene-oxide) adsorbed nanolayers

    Science.gov (United States)

    Zeng, Wenduo

    Solid-polymer interfaces play crucial roles in the multidisciplinary field of nanotechnology and are the confluence of physics, chemistry, biology, and engineering. There is now growing evidence that polymer chains irreversibly adsorb even onto weakly attractive solid surfaces, forming a nanometer-thick adsorbed polymer layer ("adsorbed polymer nanolayers"). It has also been reported that the adsorbed layers greatly impact on local structures and properties of supported polymer thin films. In this thesis, I aim to clarify adhesive and tribological properties of adsorbed poly(ethylene-oxide) (PEO) nanolayers onto silicon (Si) substrates, which remain unsolved so far. The adsorbed nanolayers were prepared by the established protocol: one has to equilibrate the melt or dense solution against a solid surface; the unadsorbed chains can be then removed by a good solvent, while the adsorbed chains are assumed to maintain the same conformation due to the irreversible freezing through many physical solid-segment contacts. I firstly characterized the formation process and the surface/film structures of the adsorbed nanolayers by using X-ray reflectivity, grazing incidence X-ray diffraction, and atomic force microscopy. Secondly, to compare the surface energy of the adsorbed layers with the bulk, static contact angle measurements with two liquids (water and glycerol) were carried out using a optical contact angle meter equipped with a video camera. Thirdly, I designed and constructed a custom-built adhesion-testing device to quantify the adhesive property. The experimental results provide new insight into the microscopic structure - macroscopic property relationship at the solid-polymer interface.

  10. The Electrochemical Properties of Thionine Adsorbed Monolayer on Gold Electrode

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    A gold electrode modified with adsorbed thionine monolayer was investigated with ac impedance and cyclic voltammetry method. It was found therewere some different redox properties for the adsorbed thionine depended on the different potential scanning rate. At the slower potential scanning rate (10 mV@s-1), the dimer of thionine appeared and possessed the catalytic activity for the oxidation of ascorbic acid.The underpotential deposition (UPD) and the bulk deposition of Cu2+ were also employed to investigate the monolayer of adsorbed thionine.

  11. ADSORPTION OF PHENYLACETIC ACID ON MACROPOROUS POLYMERIC ADSORBENTS

    Institute of Scientific and Technical Information of China (English)

    PANBingcai; CHENJinlong; 等

    2002-01-01

    Several macroporous polymeric adsorbents(NDA-999,XAD-8,X-5 and XAD-2)were emplyed in the study to adsorb phenylacetic acid from aqueous solution.Effect of salt and ambient temperature on adsorption was studied using NDA-999 adsorbent and the adsorption process conforms to Freundlich′s model reasonably.Adsorption dynamics were conducted in batch experiments in order to make clear the mechanism of adsorption process.It is proved that the squared driving force mass transfer model can be adopted to elucidate the process.The treatment process of industrial wastewater containing high strength of phenylacetic acid was proposed for cleaner production of phenylacetic acid.

  12. ADSORPTION OF PHENYLACETIC ACID ON MACROPOROUS POLYMERIC ADSORBENTS

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    Several macroporous polymeric adsorbents (NDA-999, XAD-8, X-5 and XAD-2) wereemployed in the study to adsorb phenylacetic acid from aqueous solution. Effect of salt and ambienttemperature on adsorption was studied using NDA-999 adsorbent and the adsorption processconforms to Freundlich's model reasonably. Adsorption dynamics were conducted in batchexperiments in order to make clear the mechanism of adsorption process. It is proved that thesquared driving force mass transfer model can be adopted to elucidate the process. The treatmentprocess of industrial wastewater containing high strength of phenylacetic acid was proposed forcleaner production of phenylacetic acid.

  13. Atom-Specific Identification of Adsorbed Chiral Molecules by Photoemission

    Science.gov (United States)

    Kim, J. W.; Carbone, M.; Dil, J. H.; Tallarida, M.; Flammini, R.; Casaletto, M. P.; Horn, K.; Piancastelli, M. N.

    2005-09-01

    The study of chiral adsorbed molecules is important for an analysis of enantioselectivity in heterogeneous catalysis. Here we show that such molecules can be identified through circular dichroism in core-level photoemission arising from the chiral carbon atoms in stereoisomers of 2,3-butanediol molecules adsorbed on Si(100), using circularly polarized x rays. The asymmetry in the carbon 1s intensity excited by right and left circularly polarized light is readily observed, and changes sign with the helicity of the radiation or handedness of the enantiomers; it is absent in the achiral form of the molecule. This observation demonstrates the possibility of determining molecular chirality in the adsorbed phase.

  14. [Study on LDL adsorbent modified by lauric acid].

    Science.gov (United States)

    Cong, Haixia; Du, Longbing; Fang, Bo; You, Chao

    2010-06-01

    A hydrophobic low-density lipoprotein cholesterol (LDL-C) adsorbent was synthesized with lauric acid and chitosan. The condition for adsorption was obtained by investigating the influence of adsorbent amount and adsorption time. The results of adsorption in vitro showed that the average adsorption rates for total cholesterol (TC), LDL-C, high-density lipoprotein cholesterol (HDL-C) and total protein (TP) were 47.7%, 84.7%, 18.1% and 5.9% respectively. The adsorbent possesses good selectivity in removing LDL-C.

  15. Preparation and Characterization of Impurely Irrigated Soil Adsorbent from Beaches

    Institute of Scientific and Technical Information of China (English)

    2011-01-01

    [Objective]We aimed to study the preparation methods of impurely irrigated soil adsorbent from beaches,as well as its ability to absorb phenol.[Method]Using hydrochloric acid as activator,we compared the influences of various soil adsorbents on the adsorption of phenol through the desired orthogonal tests where the usage of saw dust,concentration of hydrochloric acid,liquid-solid ratio and carbonization temperature varied.Afterwards,we characterized this soil adsorbent.[Result]The optimal conditions for pre...

  16. Preparation of Ag/TiO2-zeolite adsorbents, their desulfurization performance, and benzothiophene adsorption isotherms

    Science.gov (United States)

    Song, Hua; Yang, Gang; Song, Hua-Lin; Wang, Deng; Wang, Xue-Qin

    2017-02-01

    A series of Ag/TiO2-NaY (TY) composite adsorbents were successfully prepared and characterized by X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy, BET, scanning electron microscopy (SEM) and X-ray photoelectron spectroscopy (XPS) techniques. The effects of TiO2 and Ag contents on the structure and desulfurization performance of NaY zeolite were studied. The results show that anatase phase is the main form of TiO2 in AgTY adsorbent, and the Y-zeolite framework remained unchanged. AgTY with 6 wt % of Ag and 50 wt % of TiO2 exhibited the best desulfurization performance with the effluent volume of 63.2 mL/g at 10 mg/L sulfur breakthrough level (desulfurization rate of 95%). The benzothiophene (BT) removal performance of the various adsorbents follows the order: NaY < TiO2 < TY-50 < AgTY-50-6. The equilibrium data were modeled by Langmuir and Freundlich equations. The Langmuir model can describe well the adsorption isotherms of BT over AgTY.

  17. Sorbent track: Quantitative monitoring of adsorbed VOCs under in-situ plasma exposure

    Science.gov (United States)

    Jia, Zixian; Rousseau, Antoine

    2016-08-01

    Sorbent-TRACK is a new device developed to monitor adsorption and surface oxidation of pollutants under direct plasma exposure. It is based on direct transmitted Fourier Transformed Infrared (FTIR) spectroscopy. A pyrex reactor under controlled gas pressure and composition is inserted on the infrared beam of a commercially available Nicolet 5700 FTIR spectrometer. A substrate holder is located on the optical path of the infrared beam. A thin pellet of a dedicated catalyst (CeO2 in the present work) is inserted in a substrate holder and can be exposed to direct plasma treatment using a Dielectric Barrier Discharge. The time resolution of Sorbent-TRACK is limited by the time resolution of the Nicolet 5700 FTIR spectrometer and close to 30 s. The dynamic of the adsorption and plasma oxidation of acetone and isopropanol on CeO2 are studied and intermediates are monitored. Performances and sensitivity of Sorbent-TRACK are reported Adsorption and oxidation of acetone leads to production of adsorbed isobutene and acetic acid, where oxidation of isopropanol gives mainly to adsorbed acetone, mesityl oxide and acetate. An increase of the plasma power leads to an increase of the isopropanol and acetone oxidation rate and a related increase of the production of adsorbed intermediates.

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

    Directory of Open Access Journals (Sweden)

    Hanna M. Kowalczyńska

    2012-01-01

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

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

    Science.gov (United States)

    Stachurska, Anna; Kowalczyńska, Hanna M

    2011-01-01

    The ability of cancer cells to invade neighboring tissues is crucial for cell dissemination and tumor metastasis. It is generally assumed that cell adhesion to extracellular matrix proteins is an important stage of cancer progression. Hence, adhesion of cancer cells under in vitro conditions to proteins adsorbed on a substratum surface has been studied to provide a better understanding of cell-protein interaction mechanisms. A protein, adsorbed in an appropriate conformation on a substratum surface, creates a biologically active layer that regulates such cell functions as adhesion, spreading, proliferation and migration. In our study, we examined the interaction of PC-3 cells under in vitro conditions with fibronectin adsorbed on sulfonated polystyrene surfaces of a defined chemical composition and topography. We investigated cell adhesion to fibronectin and cell spreading. Using automatic, sequential microscopic image registration, we are the first to present observations of the dynamics of PC-3 cell spreading and the cell shape during this process. Our results show that cell adhesion and the shape of spreading cells strongly depend on the time interaction with fibronectin. The analysis of images of cytoskeletal protein distribution in the cell region near the cell-substratum interface revealed that induction of a signal cascade took place, which led to the reorganization of the cytoskeletal proteins and the activation of focal adhesion kinase (FAK).

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

    Directory of Open Access Journals (Sweden)

    G. Pirlo

    2010-04-01

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

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

    Science.gov (United States)

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

    2014-01-01

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

  2. 涂铝砂除锌吸附等温线研究及理论分析%Study and Theoretical Analysis on Adsorption Isotherm of Zinc Removal With Aluminum-Oxide-Coated Sand

    Institute of Scientific and Technical Information of China (English)

    高乃云; 徐迪民; 范瑾初; 严煦世

    2001-01-01

    The experiment and computation are introduced for adsorption isotherm of zinc removal with Aluminum-Oxide-Coated Sand (AOCS),which is described and analyzed by using the surface complexation and surface precipitation models.The isotherm of zinc removal is of Langmuir adsorption pattern and is valid for single-layer adsorption at low equilibrium concentration of Zn(Ⅱ).As the equilibrium concentration is increased to a certain extent,the sorption follows a Freundlich isotherm and multi-layer adsorption.However,further increase of the concentration results primarily in solid solution precipitation.%介绍了氧化铝涂层砂除锌吸附等温线试验、计算,并采用表面络合模型和沉积模型加以描述和分析。原水中Zn(Ⅱ)浓度低时,除锌吸附等温线属于Langmuir型,单层吸附;Zn(Ⅱ)平衡浓度增加到一定的范围时,属于Freundlich吸附等温线,多层吸附;Zn(Ⅱ)平衡浓度进一步增大,以固体溶液沉积为主。

  3. Effect of heat-treatment on phase formation and crystallization of sol–gel derived Al2O3, ZrO2–Y2O3, and Ta2O5 oxide coatings

    Directory of Open Access Journals (Sweden)

    Yang-Il Jung

    2015-06-01

    Full Text Available Various oxides of Al2O3, ZrO2–Y2O3, and Ta2O5 were coated on ferritic–martensitic steel for application as an environmental barrier layer. Sol–gel based coating was investigated to form the oxides by varying the coating parameters, such as the concentration of the precursors, the temperature of the curing, cycles of repeated runs, and additional heat-treatment. The obtained coatings revealed nano-sized granular structures. The surface morphologies were rough in alumina and zirconia, but appeared smooth in tantalum oxide. In the case of alumina and tantalum oxide, coated layers were mostly amorphous after pyrolysis at 750 °C. The crystalline phases were obtained after an additional heat-treatment at 950 °C. In the case of zirconia, a desirable oxide phase was formed when the samples were cured at 750 °C during the coating process. In addition to the heat-treatment after the coating, the repeated coatings were effective in crystallizing the coated layers and forming proper oxides.

  4. Corrosion behaviors and effects of corrosion products of plasma electrolytic oxidation coated AZ31 magnesium alloy under the salt spray corrosion test

    Science.gov (United States)

    Wang, Yan; Huang, Zhiquan; Yan, Qin; Liu, Chen; Liu, Peng; Zhang, Yi; Guo, Changhong; Jiang, Guirong; Shen, Dejiu

    2016-08-01

    The effects of corrosion products on corrosion behaviors of AZ31 magnesium alloy with a plasma electrolytic oxidation (PEO) coating were investigated under the salt spray corrosion test (SSCT). The surface morphology, cross-sectional microstructure, chemical and phase compositions of the PEO coating were determined using scanning electron microscopy (SEM) equipped with energy dispersive X-ray spectroscopy (EDS) and X-ray diffraction analysis (XRD), respectively. Further, the corrosion process of the samples under the SSCT was examined in a non-aqueous electrolyte (methanol) using electrochemical impedance spectroscopy (EIS) coupled with equivalent circuit. The results show that the inner layer of the coating was destroyed firstly and the corrosion products have significant effects on the corrosion behaviors of the coating. The results above are discussed and an electrochemical corrosion model is proposed in the paper.

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

    KAUST Repository

    Bollini, Praveen

    2012-11-21

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

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

    Data.gov (United States)

    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....

  7. A NOVEL METAL CHELATE AFFINITY ADSORBENT FOR PROTEIN UPTAKE

    Institute of Scientific and Technical Information of China (English)

    WANGYongjian; BAIShu; 等

    2001-01-01

    In this article,a spherical chitosan gel crosslinked by epichlorohydrin was prepared.It was then loaded with copper ions to produce a metal chelate affinity adsorbent for protein.The uptake of bovine serum albumin(BSA)by the affinity adsorbent was investigated.and the adsorption capacity for BSA as high as 40mg/g-wet beads was observed.The adsorption equilibrium data was well correlated by the Langmuir equation.The adsorption was considerably affected by pH.In additio.The amount of BSA adsorbed onto the beads decreased with the increasing of aqueous phase ionic strength,so adsorbed BAS can be desorbed by adjusting pH orionic strength of the solution.

  8. 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.

  9. Sol-Gel Synthesized Adsorbents for Metal Separation

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    A series of organo-ceramic adsorbents have been synthesized by a sol-gel processing technique for metal ion extraction. These adsorbents generally have significantly high metal uptake capacities, good physical-chemical stabilities, and well-designed pore geometries compared to other pre-existing metalchelating ceramic-based adsorbents. This work describes the synthesis and evaluation of pyrazole and calix[4]arene crown adsorbents for selective separation of platinum, palladium, and gold and cesium ions,respectively, from solutions. These materials exhibit mesoporous properties with high surface areas and pore volumes. The sol-gel synthesis starting with precursor silanes and titania results in gel particles of desired pore characteristics and high capacity and stability. Characterization studies, such as adsorption isotherms, breakthrough curves for fixed bed operation, and material stability, show promising results for applications to metal sepation.

  10. 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.

  11. Oil palm biomass as an adsorbent for heavy metals.

    Science.gov (United States)

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

    2014-01-01

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

  12. Residence time determination for adsorbent beds of different configurations

    Energy Technology Data Exchange (ETDEWEB)

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

    1995-02-01

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

  13. Distribution of adsorbed molecules in electronic nose sensors

    DEFF Research Database (Denmark)

    Swann, M.J.; Glidle, A.; Gadegaard, Nikolaj

    2000-01-01

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

  14. Plant waste materials from restaurants as the adsorbents for dyes

    OpenAIRE

    Pavlović Marija D.; Nikolić Ivan R.; Milutinović Milica D.; Dimitrijević-Branković Suzana I.; Šiler-Marinković Slavica S.; Antonović Dušan G.

    2015-01-01

    This paper has demonstrated the valorization of inexpensive and readily available restaurant waste containing most consumed food and beverage residues as adsorbents for methylene blue dye. Coffee, tea, lettuce and citrus waste have been utilized without any pre-treatment, thus the adsorption capacities and dye removal efficiency were determined. Coffee waste showed highest adsorbent capacity, followed by tea, lettuce and citrus waste. The dye removal was mo...

  15. 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

  16. Single-Step Assembly of Multifunctional Poly(tannic acid)-Graphene Oxide Coating To Reduce Biofouling of Forward Osmosis Membranes.

    Science.gov (United States)

    Hegab, Hanaa M; ElMekawy, Ahmed; Barclay, Thomas G; Michelmore, Andrew; Zou, Linda; Saint, Christopher P; Ginic-Markovic, Milena

    2016-07-13

    Graphene oxide (GO) nanosheets have antibacterial properties that have been exploited as a biocidal agent used on desalination membrane surfaces in recent research. Nonetheless, improved strategies for efficient and stable attachment of GO nanosheets onto the membrane surface are still required for this idea to be commercially viable. To address this challenge, we adopted a novel, single-step surface modification approach using tannic acid cross-linked with polyethylene imine as a versatile platform to immobilize GO nanosheets to the surface of polyamide thin film composite forward osmosis (FO) membranes. An experimental design based on Taguchi's statistical method was applied to optimize the FO processing conditions in terms of water and reverse solute fluxes. Modified membranes were analyzed using water contact angle, adenosine triphosphate bioluminescence, total organic carbon, Fourier transform infrared spectroscopy, ζ potential, X-ray photoelectron spectroscopy, transmission electron microscopy, and atomic force microscopy. These results show that membranes were modified with a nanoscale (<10 nm), smooth, hydrophilic coating that, compared to pristine membranes, improved filtration and significantly mitigated biofouling by 33% due to its extraordinary, synergistic antibacterial properties (99.9%).

  17. Anti-corrosion and wear properties of plasma electrolytic oxidation coating formed on high Si content Al alloy by sectionalized oxidation mode

    Science.gov (United States)

    Dai, Libin; Li, Wenfang; Zhang, Guoge; Fu, Nianqing; Duan, Qi

    2017-01-01

    In this study, a uniform and less defective ceramic coating was prepared on high Si content aluminium alloys by a sectionalized plasma electrolytic oxidation (PEO) mode. The PEO process of Al-9 wt. % Si binary alloy was performed under constant current mode followed by constant voltage mode. The surface micrographs and chemical compositions of different samples were analysed by scanning electron microscopy (SEM) and X-ray diffraction (XRD), respectively. Micro-hardness and reciprocal-sliding testers were used to measure the coatings hardness and tribological performance. It was found that the sectionalized PEO mode could produce hard and anti-friction passive oxide layers with smaller holes and fewer cracks on the Al-Si alloy, comparing with the single constant current mode. In addition, the results of polarization curves and electrochemical impedance spectroscopy (EIS) tests conducted in 3.5 wt. % NaCl solution revealed that the coatings obtained by sectionalized PEO mode had a higher corrosion resistance and provided better corrosion protection for Al-Si alloy.

  18. Effect of Al2O3 Micro-powder Additives on the Properties of Micro-arc Oxidation Coatings Formed on 6061 Aluminum Alloy

    Science.gov (United States)

    Wang, Ping; Wu, Ting; Xiao, You Tao; Pu, Jun; Guo, Xiao Yang; Huang, Jun; Xiang, Chun Lang

    2016-09-01

    Al2O3 micro-powder was suspended in the basis electrolyte to form micro-arc oxidation (MAO) coatings on 6061 aluminum alloy by MAO. During the stage of micro-arc oxidation, Al2O3 micro-powder with negative surface charge was melted by the micro-arc around the anode and incorporated into the MAO coatings. With the continuous addition of Al2O3 micro-powder, the oxidation voltages rose up firstly and then decreased. The surface and cross-sectional morphologies showed that the size of micropores decreased and the MAO coatings surface got loosened following the variation in Al2O3 micro-powder concentration. As a consequence of the changing coating structure, the corrosion resistance of the coatings decreased apparently. The micro-hardness of the coatings increased firstly and then decreased, opposite to the trend of the average friction coefficient. It revealed the minimum average friction coefficient of MAO coatings and maximum adhesion between the coatings and substrate when 2.0 g/L Al2O3 micro-powder was added into electrolyte. There were visible cracks and peelings on the coating surface merely at 4.0 g/L after thermal shock tests. The x-ray diffraction results indicated that the addition of Al2O3 micro-powder had less effect on the phase composition of MAO coatings.

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

    Science.gov (United States)

    Bahrim, Bogdana; Yu, Song

    2008-03-01

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

  20. Cryogenic adsorber design in a helium refrigeration system

    Science.gov (United States)

    Hu, Zhongjun; Zhang, Ning; Li, Zhengyu; Li, Q.

    2012-06-01

    The cryogenic adsorber is specially designed to eliminate impurities in gaseous helium such as O2, and N2 which is normally difficult to remove, based on the reversible cryotrapping of impurities on an activated carbon bed. The coconut shell activated carbon is adopted because of its developed micropore structure and specific surface area. This activated carbon adsorption is mostly determined by the micropore structure, and the adsorption rate of impurities is inversely proportional to the square of the particle sizes. The active carbon absorber's maximum permissible flow velocity is 0.25 m/s. When the gas flow velocity increases, the adsorption diffusion rate of the adsorbent is reduced, because an increase in the magnitude of the velocity resulted in a reduced amount of heat transfer to a unit volume of impure gas. According to the numerical simulation of N2 adsorption dynamics, the appropriate void tower link speed and the saturated adsorption capacity are determined. Then the diameter and height of the adsorber are designed. The mass transfer length should be taken into account in the adsorber height design. The pressure decrease is also calculated. The important factors that influence the adsorber pressure decrease are the void tower speed, the adsorbed layer height, and the active carbon particle shape and size.

  1. Activity of lactoperoxidase when adsorbed on protein layers.

    Science.gov (United States)

    Haberska, Karolina; Svensson, Olof; Shleev, Sergey; Lindh, Liselott; Arnebrant, Thomas; Ruzgas, Tautgirdas

    2008-09-15

    Lactoperoxidase (LPO) is an enzyme, which is used as an antimicrobial agent in a number of applications, e.g., food technology. In the majority of applications LPO is added to a homogeneous product phase or immobilised on product surface. In the latter case, however, the measurements of LPO activity are seldom reported. In this paper we have assessed LPO enzymatic activity on bare and protein modified gold surfaces by means of electrochemistry. It was found that LPO rapidly adsorbs to bare gold surfaces resulting in an amount of LPO adsorbed of 2.9mg/m(2). A lower amount of adsorbed LPO is obtained if the gold surface is exposed to bovine serum albumin, bovine or human mucin prior to LPO adsorption. The enzymatic activity of the adsorbed enzyme is in general preserved at the experimental conditions and varies only moderately when comparing bare gold and gold surface pretreated with the selected proteins. The measurement of LPO specific activity, however, indicate that it is about 1.5 times higher if LPO is adsorbed on gold surfaces containing a small amount of preadsorbed mucin in comparison to the LPO directly adsorbed on bare gold.

  2. 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

  3. Fabricating electrospun cellulose nanofibre adsorbents for ion-exchange chromatography.

    Science.gov (United States)

    Dods, Stewart R; Hardick, Oliver; Stevens, Bob; Bracewell, Daniel G

    2015-01-09

    Protein separation is an integral step in biopharmaceutical manufacture with diffusion-limited packed bed chromatography remaining the default choice for industry. Rapid bind-elute separation using convective mass transfer media offers advantages in productivity by operating at high flowrates. Electrospun nanofibre adsorbents are a non-woven fibre matrix of high surface area and porosity previously investigated as a bioseparation medium. The effects of compression and bed layers, and subsequent heat treatment after electrospinning cellulose acetate nanofibres were investigated using diethylaminoethyl (DEAE) or carboxylate (COO) functionalisations. Transbed pressures were measured and compared by compression load, COO adsorbents were 30%, 70% and 90% higher than DEAE for compressions 1, 5 and 10MPa, respectively, which was attributed to the swelling effect of hydrophilic COO groups. Dynamic binding capacities (DBCs) at 10% breakthrough were measured between 2000 and 12,000CV/h (2s and 0.3s residence times) under normal binding conditions, and DBCs increased with reactant concentration from 4 to 12mgBSA/mL for DEAE and from 10 to 21mglysozyme/mL for COO adsorbents. Comparing capacities of compression loads applied after electrospinning showed that the lowest load tested, 1MPa, yielded the highest DBCs for DEAE and COO adsorbents at 20mgBSA/mL and 27mglysozyme/mL, respectively. At 1MPa, DBCs were the highest for the lowest flowrate tested but stabilised for flowrates above 2000CV/h. For compression loads of 5MPa and 10MPa, adsorbents recorded lower DBCs than 1MPa as a result of nanofibre packing and reduced surface area. Increasing the number of bed layers from 4 to 12 showed decreasing DBCs for both adsorbents. Tensile strengths were recorded to indicate the mechanical robustness of the adsorbent and be related to packing the nanofibre adsorbents in large scale configurations such as pleated cartridges. Compared with an uncompressed adsorbent, compressions of 1, 5

  4. Elution by Le Chatelier's principle for maximum recyclability of adsorbents: applied to polyacrylamidoxime adsorbents for extraction of uranium from seawater.

    Science.gov (United States)

    Oyola, Yatsandra; Vukovic, Sinisa; Dai, Sheng

    2016-05-28

    Amidoxime-based polymer adsorbents have attracted interest within the last decade due to their high adsorption capacities for uranium and other rare earth metals from seawater. The ocean contains an approximated 4-5 billion tons of uranium and even though amidoxime-based adsorbents have demonstrated the highest uranium adsorption capacities to date, they are still economically impractical because of their limited recyclability. Typically, the adsorbed metals are eluted with a dilute acid solution that not only damages the amidoxime groups (metal adsorption sites), but is also not strong enough to remove the strongly bound vanadium, which decreases the adsorption capacity with each cycle. We resolved this challenge by incorporating Le Chatelier's principle to recycle adsorbents indefinitely. We used a solution with a high concentration of amidoxime-like chelating agents, such as hydroxylamine, to desorb nearly a 100% of adsorbed metals, including vanadium, without damaging the metal adsorption sites and preserving the high adsorption capacity. The method takes advantage of knowing the binding mode between the amidoxime ligand and the metal and mimics it with chelating agents that then in a Le Chatelier's manner removes metals by shifting to a new chemical equilibrium. For this reason the method is applicable to any ligand-metal adsorbent and it will make an impact on other extraction technologies.

  5. Performance evaluation of micro-arc oxidation coatings on pure titanium%纯钛微弧氧化膜的性能评价

    Institute of Scientific and Technical Information of China (English)

    李玉海; 卢世松; 赵晖; 赵艳

    2014-01-01

    The TiO2 ceramic coating with single component and larger surface area was prepared on pure titanium substrate by a novel process involving treatment of the MAO (micro-arc oxidation)and alkali-heat treatment, and then trained the coating in SBF(simulated body fluid)for the its bioactivity evaluation.The results showed that:the ceramic coating was mainly composed of anatase TiO2 ,and the porosity of the coating which with uni-form porous structure reached 1 2%;as a result of the wetting angle with SBF and deionized water,the coating treated by alkali-heat method showed good hydrophilic;The coating treated by alkali-heat method was com-pletely covered by bone-like apatite when it was cultured in SBF for 14 d,and the calcium deficiency apatite grew on the coating which with perfect bioactivity was similar to the human bone in composition.%采用微弧氧化-碱热处理复合的方法,在纯钛表面制备出较大表面积且成分单一的 TiO2陶瓷膜,并在模拟体液中对膜层的生物活性予以评价。结果表明,纯钛微弧氧化膜层主要由锐钛矿型的 TiO2构成,其表面孔径均匀,孔隙率达到12%;经碱热处理后,与模拟体液和去离子水的润湿角实验证明膜层具有较好的亲水性;碱热处理后的膜层置于模拟体液中培养14 d后,膜层表面被生长出的类骨磷灰石完全覆盖,证明其具有良好的生物活性,且生长出的缺钙型磷灰石与人体自然骨成分相似。

  6. Simple Adsorbates on Transition Metal Surfaces: A Joint Chemical and Physical Approach

    Science.gov (United States)

    1989-02-28

    commonly treated with benzotriazole ( BTA ) to inhibit corrosion. BTA is thought to lose a proton at N1 to the oxide coating, which is present on...commercially 5 available copper, through the formation of water. BTA ° is proposed to bind to the surface through the nitrogen lone pairs, rather thaii...bound copper-pyridine complexes exist, but only a few r- bound species have been found. It is unclear whether BTA - lies parallel or perpendicular to the

  7. Extracting Uranium from Seawater: Promising AF Series Adsorbents

    Energy Technology Data Exchange (ETDEWEB)

    Das, S.; Oyola, Y.; Mayes, Richard T.; Janke, Chris J.; Kuo, L. -J.; Gill, G.; Wood, J. R.; Dai, S.

    2016-04-20

    A new family of high-surface-area polyethylene fiber adsorbents named the AF series was recently developed at the Oak Ridge National Laboratory (ORNL). The AF series adsorbents were synthesized by radiation-induced graft polymerization of acrylonitrile and itaconic acid (at different monomer/comonomer mol ratios) onto high surface area polyethylene fibers. The degree of grafting (%DOG) of AF series adsorbents was found to be 154-354%. The grafted nitrile groups were converted to amidoxime groups by treating with hydroxylamine. The amidoximated adsorbents were then conditioned with 0.44 M KOH at 80 °C followed by screening at ORNL with sodium-based synthetic aqueous solution, spiked with 8 ppm uranium. The uranium adsorption capacity in simulated seawater screening ranged from 170 to 200 g-U/kg-ads irrespective of %DOG. A monomer/comonomer molar ratio in the range of 7.57-10.14 seemed to be optimum for highest uranium loading capacity. Subsequently, the adsorbents were also tested with natural seawater at Pacific Northwest National Laboratory (PNNL) using flow-through column experiments to determine uranium loading capacity with varying KOH conditioning times at 80 °C. The highest adsorption capacity of AF1 measured after 56 days of marine testing was demonstrated as 3.9 g-U/kg-adsorbent and 3.2 g-U/kg-adsorbent for 1 and 3 h of KOH conditioning at 80 °C, respectively. Based on capacity values of several AF1 samples, it was observed that changing KOH conditioning from 1 to 3 h at 80 °C resulted in a 22-27% decrease in uranium adsorption capacity in seawater.

  8. Biocompatibility of pure titanium implant surface micro-arc oxidation coating%纯钛种植体表面微弧氧化涂层的生物相容性

    Institute of Scientific and Technical Information of China (English)

    张强; 王健平; 胡美玲; 孟祥才; 王静

    2011-01-01

    BACKGROUND: Biological effects of various pure titanium implant surface micro -arc oxidation coatings are different.OBJECTIVE: To study the effects of three different micro -arc oxidation coating palatal implant titanium tablets on mouse osteoblast cell proliferation, alkaline phosphatase activity and beta 1-integrin gene expression level.METHODS: Using international common mice lines (MC3T3-E1), three different coated titanium pieces were used as influencing factors, pure titanium group as control group. MTT method and electron microscopic observation were conducted for cell adhesion and cell proliferation, PNPP was used for determination of alkaline phosphatase activity, RT-PCR method to detect beta 1-integrin expression in mouse osteoblasts.RESULTS AND CONCLUSION: The MTT value, alkaline phosphatase activity, beta 1-integrin gene expression level and electron microscopic observation showed calcium, phosphorus, magnesium, zinc coated titanium pieces of titanium dioxide had the best biocompatibility, titanium dioxide coating titanium containing calcium containing phosphorus salt was secondary, and titanium dioxide coated titanium slice was the worst. The results showed that mouse osteoblasts on the porous of calcium,phosphorus, magnesium, zinc coated titanium pieces had the best adhesion and proliferative abilities.%背景:各种纯钛种植体表面微弧氧化涂层效果不尽相同.目的:观察3种不同微弧氧化涂层种植体钛片对小鼠成骨细胞的细胞增殖、碱性磷酸酶活性和β1-integrin的基因表达水平的影响.方法:采用国际常用小鼠成骨细胞系(MC3T3-E1),3种不同涂层钛片作为影响因素,纯钛作为对照,采用MTT法和电镜法观察细胞附着和细胞增殖,PNPP法测定碱性磷酸酶的活性,RT-PCR法检测β1-integrin在小鼠成骨细胞中的表达.结果与结论:MTT值、碱性磷酸酶值、β1-integrin的基因表达水平和电镜观察均显示含钙、磷、镁、锌元素的二氧化钛涂

  9. Preparation of Lanthanum Nickel Oxide-Coated Ni Sheet Anodes and Their Application to Electrolytic Production of (CF3)3N in (CH3)4NF·4.0HF Melt

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    A new process for electrolytic production of a perfluorinated compound, (CF3)3N, using lanthanum nickel oxide-coated Ni sheet anode in the (CH3)4NF·4.0HF melt at room temperature, was developed. Thin films of the lanthanum nickel oxides were prepared on Ni sheets by sol-gel coating method using polyvinlylpyrrolidone(PVP). The main components of the thin films were La2O3, LaNiO3, and La2NiO4 at 500, 750 and 1000 ℃, respectively. The anode performance in the (CH3)4NF·4.0HF melt depends greatly on the main component of the thin film, and the LaNiO3-coated Ni sheet anode gives the best anode performance. The potential of LaNiO3-coated Ni sheet anode remains constant at 5.9 V during electrolysis at 20 mA·cm-2 in the (CH3)4NF·4.0HF melt for 100 h. This is because LaNiO3 and NiF3 and/or Ni2F5, the latter of which was formed during electrolysis, in the film give a high electronic conductivity to the surface film during electrolysis. The maximum mole fraction of (CF3)3N (21.4%) was obtained at 20 mA·cm-2 in (CH3)4NF·4.0HF melt using the LaNiO3-coated Ni sheet.

  10. Structural characteristics and oil-removal mechanisms of the adsorbents made from petrochemical sludge

    Institute of Scientific and Technical Information of China (English)

    LIU Jian-bin; SANG Yi-ming; TAN Wen-jie; HE Xu-wen; LI Fa-sheng

    2004-01-01

    A new type of carbon-inorganic absorbent with good oil-removing performance is prepared by sintering and activating petrochemical sludge. Of the absorbents prepared by three different methods (non-activated, vapor /840 ℃/6 h, CO2/1 000 ℃/2 h), the one prepared by the second method is the best in oil-removing, which can remove 60% of oil from petrochemical wastewater with a concentration of 76.42 mg/L. X-ray Diffraction (XRD) analysis shows that the constituents of the adsorbents are basically similar to those of inorganic granulating materials, such as SiO2, Al2O3, orthoclase feldspar, iron ore, etc. Composition analysis reveals that the activated absorbent has a large specific surface area with a high carbon content in activated compositions and a good oil-removing capability.

  11. Novel recyclable adsorbent for the removal of copper(II) and lead(II) from aqueous solution.

    Science.gov (United States)

    Niu, Yaolan; Li, Kan; Ying, Diwen; Wang, Yalin; Jia, Jinping

    2017-04-01

    Adsorbents synthesized with biopolymer have been widely used in the removal of toxic metal ions. Novel high-efficiency, recyclable, and low-cost adsorbents have received more and more attention. Chitosan and cellulose are the most abundant biopolymers in nature. Composite modified adsorbent (CSTEC) was synthesized as novel fibrous materials for the adsorption of Cu(2+) and Pb(2+) ions from water in this study. The functional fiber was characterized to investigate the surface appearance, functional groups, crystallinity, and thermal stability. The kinetics study revealed that adsorption processes of Cu(2+) and Pb(2+) ions on the CSTEC followed the second-order kinetics model. CSTEC showed better performance (Cu(2+), 95.24; Pb(2+), 144.93mgg(-1)) than most of other adsorbents. The co-existing ions (K(+), Na(+), Mg(2+)) had no significant influence on the removal of target ions by the CSTEC. The excellent reusability indicated that CSTEC had the promising application in the treatment of toxic metal pollution.

  12. Adsorption of Hg(II) from aqueous solutions using TiO2 and titanate nanotube adsorbents

    Science.gov (United States)

    López-Muñoz, María-José; Arencibia, Amaya; Cerro, Luis; Pascual, Raquel; Melgar, Álvaro

    2016-03-01

    Titania and titanate nanotubes were evaluated as adsorbents for the removal of Hg(II) from aqueous solution. Commercial titanium dioxide (TiO2-P25, Evonik), a synthesized anatase sample obtained by the sol-gel method (TiO2-SG) and titanate nanotubes (TNT) prepared via hydrothermal treatment were compared. Mercury adsorption was analysed by kinetic and equilibrium experiments, studying the influence of pH and the type of adsorbents. The kinetics of Hg(II) adsorption on titania and titanate nanotubes could be well described by the pseudo-second order model. It was found that the process is generally fast with small differences between adsorbents, which cannot be explained by their dissimilarities in textural properties. Equilibrium isotherm data were best fitted with the Sips isotherm model. The maximum adsorption capacities of Hg(II) were achieved with titanate nanotubes sample, whereas between both titania samples, TiO2-SG exhibited the highest mercury uptake. For all adsorbents, adsorption capacities were enhanced as pH was increased, achieving at pH 10 Hg(II) adsorption capacities of 100, 121, and 140 mg g-1 for TiO2-P25, TiO2-SG, and TNT, respectively. Differences between samples were discussed in terms of their crystalline phase composition and chemical nature of both, mercury species and surface active sites.

  13. Effect of biomass addition on the surface and adsorption characterization of carbon-based adsorbents from sewage sludge

    Institute of Scientific and Technical Information of China (English)

    Changzi Wu; Min Song; Baosheng Jin; Yimin Wu; Yaji Huang

    2013-01-01

    Sewage sludge with the additive corn cob was used as prescusor to prepare sludge-based carbon adsorbents by pyrolysis method.And then,the carbonizated products were activated with potassium hydroxide.The mixing ratio of the corn cob to sewage sludge was investigated.The surface area and pore size distribution,elemental composition,surface chemistry structure and the surface physical morphology were determined and compared.The results demonstrated that the addition of corn cob into the sewage sludge sample could effectively improve the surface area (from 287 to 591 m2/g) and the microporosity (from 5% to 48%) of the carbon based adsorbent,thus enhancing the adsorption behavior.The sulfur dioxide adsorption capacity was measured according to breakthrough test.It was found that the sulfur dioxide adsorption capacity of the adsorbents was obviously enhanced after the addition of the corn cob.It is presumed that not only highly porous adsorbents,but also a high metallic content of these materials are required to achieve good performances.

  14. Effect of biomass addition on the surface and adsorption characterization of carbon-based adsorbents from sewage sludge.

    Science.gov (United States)

    Wu, Changzi; Song, Min; Jin, Baosheng; Wu, Yimin; Huang, Yaji

    2013-02-01

    Sewage sludge with the additive corn cob was used as prescusor to prepare sludge-based carbon adsorbents by pyrolysis method. And then, the carbonizated products were activated with potassium hydroxide. The mixing ratio of the corn cob to sewage sludge was investigated. The surface area and pore size distribution, elemental composition, surface chemistry structure and the surface physical morphology were determined and compared. The results demonstrated that the addition of corn cob into the sewage sludge sample could effectively improve the surface area (from 287 to 591 m2/g) and the microporosity (from 5% to 48%) of the carbon based adsorbent, thus enhancing the adsorption behavior. The sulfur dioxide adsorption capacity was measured according to breakthrough test. It was found that the sulfur dioxide adsorption capacity of the adsorbents was obviously enhanced after the addition of the corn cob. It is presumed that not only highly porous adsorbents, but also a high metallic content of these materials are required to achieve good performances.

  15. Novel adsorbent from agricultural waste (cashew NUT shell for methylene blue dye removal: Optimization by response surface methodology

    Directory of Open Access Journals (Sweden)

    Ramalingam Subramaniam

    2015-09-01

    Full Text Available Activated carbon, prepared from an agricultural waste, cashew nut shell (CNS was utilized as an adsorbent for the removal of methylene blue (MB dye from aqueous solution. Batch adsorption study was carried out with variables like pH, adsorbent dose, initial dye concentration and time. The response surface methodology (RSM was applied to design the experiments, model the process and optimize the variable. A 24 full factorial central composite design was successfully employed for experimental design and analysis of the results. The parameters pH, adsorbent dose, initial dye concentration, and time considered for this investigation play an important role in the adsorption studies of methylene blue dye removal. The experimental values were in good agreement with the model predicted values. The optimum values of pH, adsorbent dose, initial dye concentration and time are found to be 10, 2.1846 g/L, 50 mg/L and 63 min for complete removal of MB dye respectively.

  16. 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.

  17. 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.

  18. Effect of zinc and cerium addition on property of copper-based adsorbents for phosphine adsorption

    Institute of Scientific and Technical Information of China (English)

    宁平; 易红宏; 余琼粉; 唐晓龙; 杨丽萍; 叶智青

    2010-01-01

    A series of copper-based activated carbon (AC) adsorbents were prepared in order to investigate the effect of Zn, Ce addition on Cu-based AC adsorbent for phosphine (PH3) adsorption removal from yellow phosphorous tail gas. N2 adsorption isotherm and X-ray diffrac-tion (XRD) results suggested that the addition of Zn could increase the adsorbent ultramicropores, decrease the adsorbent supermicropores and the adsorbent average pore diameter. Therefore it enhanced the PH3 adsorption capacity. Appropriate amoun...

  19. Studies on The Adsorption Capacity for Bilirubin of The Adsorbent Chitosan-β-Cyclodextrin

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    The adsorbent crosslinked chitosan-β-cyclodextrin (β-CD) was prepared by the reaction of glutaraldehyde with chitosan and β-cyclodextrin. This type of adsorbent has high adsorption capacity for unconjugated bilirubin. The adsorption capacity was related to the β-CD content of the adsorbent; phosphate buffer concentration; temperature; pH value; ionic strength and the adsorbent beads. The results indicated that the chitosan-β-CD was a good adsorbent for unconjugated bilirubin with high capacity.

  20. Electronic and electrochemical doping of graphene by surface adsorbates

    Directory of Open Access Journals (Sweden)

    Hugo Pinto

    2014-10-01

    Full Text Available Many potential applications of graphene require its precise and controllable doping with charge carriers. Being a two-dimensional material graphene is extremely sensitive to surface adsorbates, so its electronic properties can be effectively modified by deposition of different atoms and molecules. In this paper, we review two mechanisms of graphene doping by surface adsorbates, namely electronic and electrochemical doping. Although, electronic doping has been extensively studied and discussed in the literature, much less attention has been paid to electrochemical doping. This mechanism can, however, explain the doping of graphene by adsorbates for which no charge transfer is expected within the electronic doping model. In addition, electrochemical doping is in the origin of the hysteresis effects often observed in graphene-based field effect transistors when operating in the atmospheric environment.

  1. ADSORPTION OF DINITROPHENOLS ONTO POLYMERIC ADSORBENTS AND ITS MECHANISM

    Institute of Scientific and Technical Information of China (English)

    SHIZuoqing; XUMancai; 等

    2000-01-01

    The adsorption of 2,4-dinitrophenol and 2,6-dinitrophenol on non-polar and polar adsorbents was studied.The results showed that the equilibrium adsorption did not comply with the Langmuir equation and was not mono-layer adsorption .It is of interest to notice that the effect of pH on the adsorption of 2,4-or 2,6-dinitrophenol onto ADS-7 and ADS-21 was very small,The result is explained by hydrogen bonding interaction between 2,4-or 2,6-dinitrophenol and the adsorbent ADS-21.The large adsorption capacity of dinitrophenol onto ADS-21,which was about 500mg/g at an equilibrium concentration of 400mg/L,and the small dinitrophenol leakage in the effluent from ADS-21 column presented a good prospect for treatment of wastewater containing dinitrophenol with adsorbent ADS-21.

  2. Synthesis of silica adsorbent and its selective separation for flavone

    Institute of Scientific and Technical Information of China (English)

    Yuqing ZHANG; Yahui ZHANG; Zhen QIN; Zhenrong MA

    2008-01-01

    One kind of built,in silica adsorbent, which has high adsorption selectivity to rutin, was synthesized using molecular imprinting technology by the following steps:synthesis of precursor from the reaction between water soluble rutin (as template molecule) and the functional monomer chloropropyltriethoxysilane, co,hydrolysis of the precursor and tetraethoxysilane (TEOS), sol,gel aging process, and removal of template molecules. The results of adsorption experiment show that this adsorbent has a high adsorption capacity for rutin, and good adsorptionselectivity towards rutin even under the interference of a flavone with a similar structure. TEM photos suggest that nanocaves corresponding to rutin were formed inside the adsorbent while FTIR spectra indicate that new bond was generated during the recognition process.

  3. A Review of Adsorbents Used for Storm Water Runoff Cleaning

    Directory of Open Access Journals (Sweden)

    Andrius Agintas

    2011-04-01

    Full Text Available Heavy metals, petroleum products, sediments and other pollutants get in the environment with insufficiently cleaned storm water runoff. Contaminated storm water runoff is one of the most significant sources for pollution in rivers, lakes and estuaries. Storm water runoff must be treated using not only simple methods but also using adsorption processes. Adsorbents can be natural organic, natural nonorganic and synthetic. Main adsorption characteristic, way of utilization and storm water runoff inflow rate, quantity and pollution need to be investigated when trying to use adsorbents in reasonably way. It is very important to treat storm water properly during the primary mechanical treatment otherwise adsorbents will act as mechanical filters.Article in Lithuanian

  4. Aminosilane-grafted polymer/silica hollow fiber adsorbents for CO₂ capture from flue gas.

    Science.gov (United States)

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

    2013-05-01

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

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

    Science.gov (United States)

    Arpanaei, A; Winther-Jensen, B; Theodosiou, E; Kingshott, P; Hobley, T J; Thomas, O R T

    2010-10-29

    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

  6. Grazing incidence ion erosion in the presence of adsorbates

    Energy Technology Data Exchange (ETDEWEB)

    Redinger, A; Michely, T [II. Physikalisches Institut, Universitaet zu Koeln, 50937 Koeln (Germany); Rosandi, Y; Urbassek, H M [Fachbereich Physik, Technische Universitaet Kaiserslautern, Erwin-Schroedinger-Strasse, 67663 Kaiserslautern (Germany)], E-mail: redinger@ph2.uni-koeln.de

    2009-06-15

    The effect of a background pressure of adsorbable species on sputtering and surface damage in grazing incidence ion erosion of Pt(111) is investigated by scanning tunneling microscopy and molecular dynamics simulations. The background pressure implies a partial surface coverage with adsorbates, which in turn causes an enhancement of the erosion rate by a factor of up to 40 compared to the clean case. Partial pressures of molecular oxygen and carbon monoxide were maintained during ion erosion with 5 keV Ar{sup +} for various grazing angles between 81 deg. and 87 deg. and temperatures ranging from 400 to 550 K.

  7. AQUATIC PHOTOLYSIS OF OXY-ORGANIC COMPOUNDS ADSORBED ON GOETHITE.

    Science.gov (United States)

    Goldberg, Marvin C.

    1985-01-01

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

  8. Microstructure of sepiolite and its adsorbing properties to dodecanol

    Institute of Scientific and Technical Information of China (English)

    WANG Fei; LIANG Jin-sheng; TANG Qing-guo; MENG Jun-ping; WU Zi-zhao; LI Guo-sheng

    2006-01-01

    The acid treatment process,testing methods,microstrcture of sepiolite mineral materials and their adsorbing properties to dodecanol were studied respectively. The results show that by acid treatment to raw sepiolite thinner fibre clusters and single fibres turn up,the pore volume and the number of micropore and mesopore in sepiolite all increase,and adsorbing properties of modified sepiolite to dodecanol are improved significantly. In the combined materials of dodecanol and sepiolite prepared under the best condition,the proportion of dodecanol is 67.96%,and then it is much higher than the result calculated from traditional BET method.

  9. 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.

  10. Preparation of thiophilic paramagnetic adsorbent for separation of antibodies

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    The micron-sized mierospheres with superparamagnetic property were synthesized with vinyl acetate and divinylbenzene by microsuspension polymerization. After the complete alcoholysis, these hydroxyl-functionalized microspheres were activated by divinylfone and modified with mercaptoethanol to prepare the thiophilic magnetic adsorbent, which was used to specifically isolate immunoglobulin G (IgG) from human serum. This thiophilic magnetic adsorbent performed an evident salt-dependent adsorption behavior for IgG. Due to their salt-promoted adsorption towards IgG under high salt concentration, the absorbed antibodies could be extracted in low salt concentration with high purity.

  11. Hydrogen molecule on lithium adsorbed graphene: A DFT study

    Science.gov (United States)

    Kaur, Gagandeep; Gupta, Shuchi; Gaganpreet, Dharamvir, Keya

    2016-05-01

    Electronic structure calculations for the adsorption of molecular hydrogen on lithium (Li) decorated and pristine graphene have been studied systematically using SIESTA code [1] within the framework of the first-principle DFT under the Perdew-Burke-Ernzerhof (PBE) form of the generalized gradient approximation (GGA)[2], including spin polarization. The energy of adsorption of hydrogen molecule on graphene is always enhanced by the presence of co-adsorbed lithium. The most efficient adsorption configuration is when H2 is lying parallel to lithium adsorbed graphene which is in contrast to its adsorption on pristine graphene (PG) where it prefers perpendicular orientation.

  12. Selection of non-adsorbing alkali components

    Energy Technology Data Exchange (ETDEWEB)

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

    1992-11-01

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

  13. Selection of non-adsorbing alkali components

    Energy Technology Data Exchange (ETDEWEB)

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

    1992-01-01

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

  14. Inorganic-organic phase arrangement as a factor affecting gas-phase desulfurization on catalytic carbonaceous adsorbents.

    Science.gov (United States)

    Ansari, Adil; Bandosz, Teresa J

    2005-08-15

    Dried sewage sludge was physically mixed with waste paper (paper-to-sludge ratios from 25% to 75%). To increase the catalytic activity, from 1% to 6% calcium hydroxide was added to the mixtures. Then the precursors were carbonized at 950 degrees C. The performance of materials as H2S adsorbents was tested using a home-developed dynamic breakthrough test. The samples, before and after the adsorption process, were characterized by adsorption of nitrogen, potentiometric titration, thermal analysis, XRF, and SEM. Differences in the performance were linked to the surface properties. Itwas found that mixing paper with sludge increases the amount of H2S adsorbed/oxidized in comparison with that adsorbed/oxidized by the adsorbents obtained from pure precursors (sludge or waste paper) and the capacity is comparable to those of the best activated carbons existing on the market. Although both sewage sludge and waste paper provide the catalytic centers for hydrogen sulfide oxidation, the dispersion of the catalyst and its location within accessible pores is an important factor. The presence of cellulose in the precursor mixture leads to the formation of a light macroporous char whose particles physically separate the inorganic catalytic phase of the sewage sludge origin, decreasing the density of the adsorbent and thus providing more space for storage of oxidation products. This, along with calcium, contributes to a significant increase in the capacity of the materials as hydrogen sulfide adsorbents. On their surface about 30 wt % H2S can be adsorbed, mainly as elemental sulfur or sulfates. The results demonstrate the importance of the composition and arrangement of inorganic/ organic phases for the removal of hydrogen sulfide. The interesting finding is that although some microporosity is necessary to increase the storage area for oxidation products, the carbonaceous phase does not need to be highly microporous. It is important that it provides space for deposition of sulfur

  15. Composite Coatings with Ceramic Matrix Including Nanomaterials as Solid Lubricants for Oil-Less Automotive Applications

    Directory of Open Access Journals (Sweden)

    Posmyk A.

    2016-06-01

    Full Text Available The paper presents the theoretical basis of manufacturing and chosen applications of composite coatings with ceramic matrix containing nanomaterials as a solid lubricant (AHC+NL. From a theoretical point of view, in order to reduce the friction coefficient of sliding contacts, two materials are required, i.e. one with a high hardness and the other with low shear strength. In case of composite coatings AHC+NL the matrix is a very hard and wear resistant anodic oxide coating (AHC whereas the solid lubricant used is the nanomaterial (NL featuring a low shear strength such as glassy carbon nanotubes (GC. Friction coefficient of cast iron GJL-350 sliding against the coating itself is much higher (0.18-0.22 than when it slides against a composite coating (0.08-0.14. It is possible to reduce the friction due to the presence of carbon nanotubes, or metal nanowires.

  16. 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.

  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, cha...

  18. Polarity of an MCM-41 adsorbent surface modified with methyl and phenyl groups based on data from gas chromatography

    Science.gov (United States)

    Sukhareva, D. A.; Gus'kov, V. Yu.; Karpov, S. I.; Kudasheva, F. Kh.; Roessner, F.; Borodina, E. V.

    2016-02-01

    The polarity of an MCM-41 adsorbent surface and organosilylated composites based on it with grafted trimethylsilane and dimethylphenylsilane groups is studied via inverse gas chromatography at infinite dilution. The dispersion and specific components of the value proportional to the Helmholtz adsorption energy are calculated, and a comparative analysis of the surface polarity of MCM-41 and its modified analogs relative to the commercially available C-120 silica gel is performed. The electrostatic and donor-acceptor components of the specific Helmholtz adsorption energy are calculated through linear decomposition of the adsorption energy. It is established that MCM-41 is less polar than C-120. The modification of the initial adsorbent surface leads to a reduction in polarity, due mainly to the weakening of induction and orientation interactions. It is concluded that the surfaces of the modified samples retain the ability to form hydrogen bonds.

  19. Microstructure and Properties of Composite Coatings Obtained on Aluminium Alloys

    Directory of Open Access Journals (Sweden)

    Bara M.

    2016-09-01

    Full Text Available This paper presents methods of modifying the anode surface layers of Al2O3 by introducing carbon to their microstructure. Composite coatings were prepared using two different methods. In the first, coatings were formed by means of oxidation under constant current conditions. Anodic oxidation of aluminium was conducted in a multicomponent electrolyte with the addition of organic acids and graphite. The second method was based on the formation of oxide coatings in an electrolyte without the addition of graphite or heat treatment of the layers of succinic acid. The obtained coatings were tested using SEM, TEM, and GDOES (glow discharge optical emission spectrometry and their tribological and stereometric properties were measured. The study demonstrated the beneficial effects of the methods when used to improve the tribological properties of sliding couples.

  20. PREPARATION AND ADSORBABILITY OF DEXTRAN MICROSPHERES WITH UNIFORM DIAMETER

    Institute of Scientific and Technical Information of China (English)

    Ri-sheng Yao; Wen-xia Gao; Jing Sun; Ya-hua You

    2005-01-01

    The method of preparing uniform dextran microspheres with a narrow diameter distribution was introduced and the adsorbability of these microspheres was evaluated. The microspheres were prepared in W/O microemulsion using 0.5% dextran solution as the aqueous phase and n-hexane as the oil phase. Characteristics of the prepared dextran microspheres were examined with laser light blocking technique, optical microscope and ultraviolet spectrometer. The results show that the prepared dextran microspheres have uniform morphology and narrow diameter distribution, nearly 92% of them having a diameter of 56.6 μm. In vitro evaluation of adsorbability, wet dextran microspheres have good adsorption of 98.32 mg/g of model drug methylene blue in 20.86 mg/L methylene blue solution at 25℃. The adsorption of dried dextran microspheres under the same condition is 132.15 mg/g, which is even higher. And the adsorbability of dextran microspheres has significant relationship with the concentration of methylene blue and temperature. The adsorbability is better at lower temperature and higher concentration of methylene blue.

  1. High-capacity hydrogen storage in Al-adsorbed graphene

    Science.gov (United States)

    Ao, Z. M.; Peeters, F. M.

    2010-05-01

    A high-capacity hydrogen storage medium—Al-adsorbed graphene—is proposed based on density-functional theory calculations. We find that a graphene layer with Al adsorbed on both sides can store hydrogen up to 13.79wt% with average adsorption energy -0.193eV/H2 . Its hydrogen storage capacity is in excess of 6wt% , surpassing U. S. Department of Energy (DOE’s) target. Based on the binding-energy criterion and molecular-dynamics calculations, we find that hydrogen storage can be recycled at near ambient conditions. This high-capacity hydrogen storage is due to the adsorbed Al atoms that act as bridges to link the electron clouds of the H2 molecules and the graphene layer. As a consequence, a two-layer arrangement of H2 molecules is formed on each side of the Al-adsorbed graphene layer. The H2 concentration in the hydrogen storage medium can be measured by the change in the conductivity of the graphene layer.

  2. Analytical phase diagrams for colloids and non-adsorbing polymer

    NARCIS (Netherlands)

    Fleer, G.J.; Tuinier, R.

    2008-01-01

    We review the free-volume theory (FVT) of Lekkerkerker et al. [Europhys. Lett. 20 (1992) 5591 for the phase behavior of colloids in the presence of non-adsorbing polymer and we extend this theory in several aspects: (i) We take the solvent into account as a separate component and show that the natur

  3. HYDROGEN BONDING IN POLYMERIC ADSORBENTS BASED ADSORPTION AND SEPARATION

    Institute of Scientific and Technical Information of China (English)

    XUMancai; SHIZuoqing; 等

    2000-01-01

    After a concise introduction of hydrogen bonding effects in solute-solute and solute-solvent bonding,the design of polymeric adsorbents based on hydrogen bonding ,selectivity in adsorption through hydrogen bonding,and characterization of hydrogen bonding in adsorption and separation were reviewed with 28 references.

  4. Gelation of polymers adsorbed at a water-air interface.

    NARCIS (Netherlands)

    Cohen Stuart, M.A.; Keurentjes, J.T.F.; Bonekamp, B.C.; Fraaye, J.G.E.M.

    1986-01-01

    Rheological data on air—water interfaces with adsorbed water-soluble polymer layers are presented which prove the existence of a surface gel. The gel is found to behave thixotropically and its yield stress is determined under various conditions. The gelation seems to be related to the lack of relaxa

  5. Chiral switching by spontaneous conformational change in adsorbed organic molecules.

    Science.gov (United States)

    Weigelt, Sigrid; Busse, Carsten; Petersen, Lars; Rauls, Eva; Hammer, Bjørk; Gothelf, Kurt V; Besenbacher, Flemming; Linderoth, Trolle R

    2006-02-01

    Self-assembly of adsorbed organic molecules is a promising route towards functional surface nano-architectures, and our understanding of associated dynamic processes has been significantly advanced by several scanning tunnelling microscopy (STM) investigations. Intramolecular degrees of freedom are widely accepted to influence ordering of complex adsorbates, but although molecular conformation has been identified and even manipulated by STM, the detailed dynamics of spontaneous conformational change in adsorbed molecules has hitherto not been addressed. Molecular surface structures often show important stereochemical effects as, aside from truly chiral molecules, a large class of so-called prochiral molecules become chiral once confined on a surface with an associated loss of symmetry. Here, we investigate a model system in which adsorbed molecules surprisingly switch between enantiomeric forms as they undergo thermally induced conformational changes. The associated kinetic parameters are quantified from time-resolved STM data whereas mechanistic insight is obtained from theoretical modelling. The chiral switching is demonstrated to enable an efficient channel towards formation of extended homochiral surface domains. Our results imply that appropriate prochiral molecules may be induced (for example, by seeding) to assume only one enantiomeric form in surface assemblies, which is of relevance for chiral amplification and asymmetric heterogenous catalysis.

  6. Interactions of organic contaminants with mineral-adsorbed surfactants

    Science.gov (United States)

    Zhu, L.; Chen, B.; Tao, S.; Chiou, C.T.

    2003-01-01

    Sorption of organic contaminants (phenol, p-nitrophenol, and naphthalene) to natural solids (soils and bentonite) with and without myristylpyridinium bromide (MPB) cationic surfactant was studied to provide novel insight to interactions of contaminants with the mineral-adsorbed surfactant. Contaminant sorption coefficients with mineral-adsorbed surfactants, Kss, show a strong dependence on surfactant loading in the solid. At low surfactant levels, the Kss values increased with increasing sorbed surfactant mass, reached a maximum, and then decreased with increasing surfactant loading. The Kss values for contaminants were always higher than respective partition coefficients with surfactant micelles (Kmc) and natural organic matter (Koc). At examined MPB concentrations in water the three organic contaminants showed little solubility enhancement by MPB. At low sorbed-surfactant levels, the resulting mineral-adsorbed surfactant via the cation-exchange process appears to form a thin organic film, which effectively "adsorbs" the contaminants, resulting in very high Kss values. At high surfactant levels, the sorbed surfactant on minerals appears to form a bulklike medium that behaves essentially as a partition phase (rather than an adsorptive surface), with the resulting Kss being significantly decreased and less dependent on the MPB loading. The results provide a reference to the use of surfactants for remediation of contaminated soils/sediments or groundwater in engineered surfactant-enhanced washing.

  7. Extracting Uranium from Seawater: Promising AI Series Adsorbents

    Energy Technology Data Exchange (ETDEWEB)

    Das, S.; Oyola, Y.; Mayes, R. T.; Janke, C. J.; Kuo, L. -J.; Gill, G.; Wood, J. R.; Dai, S.

    2016-04-20

    A new series of adsorbents (AI10 through AI17) were successfully developed at ORNL by radiation induced graft polymerization (RIGP) of acrylonitrile (AN) and vinylphosphonic acid (VPA) (at different mole to mole ratios) onto high surface area polyethylene fiber, with high degrees of grafting (DOG) varying from 110 to 300%. The grafted nitrile groups were converted to amidoxime groups by reaction with 5 wt % hydroxylamine at 80 °C for 72 h. The amidoximated adsorbents were then conditioned with 0.44 M KOH at 80 °C followed by screening at ORNL with prescreening brine spiked with 8 ppm uranium. Uranium adsorption capacities in prescreening ranged from 171 to 187 g-U/kg-ads irrespective of percent DOG. The performance of the adsorbents with respect to uranium adsorption in natural seawater was also investigated using flow-throughcolumn testing at the Pacific Northwest National Laboratory (PNNL). Three hours of KOH conditioning led to higher uranium uptake than 1 h of conditioning. The adsorbent AI11, containing AN and VPA at the mole ratio of 3.52, emerged as the potential candidate for the highest uranium adsorption (3.35 g-U/kg-ads.) after 56 days of exposure in seawater flow-through-columns. The rate of vanadium adsorption over uranium linearly increased throughout the 56 days of exposure. The total mass of vanadium uptake was ~5 times greater than uranium after 56 days.

  8. Organobentonites as multifunctional adsorbents of organic and inorganic water pollutants

    Directory of Open Access Journals (Sweden)

    Jović-Jovičić Natаša

    2014-01-01

    Full Text Available The aim of this study was to find a low cost, easy to synthesize and efficient adsorbent for the simultaneous adsorption of both organic and inorganic pollutants (including textile dyes, toxic metals etc.. The starting material, domestic bentonite clay from Bogovina was modified with amounts of hexadecyltrimethylammonium cations corresponding to 0.5 and 1.0 times of the value of the cation exchange capacity value. The organobentonites were tested as adsorbents in a three-dye-containing solution, a three-component solution of Pb2+, Cd2+ and Ni2+ and a hexa- component solution containing all investigated dyes and toxic metal cations. The used adsorbents showed the highest affinity toward Acid Yellow 99 and Ni2+ ions. Dye adsorption was enhanced in the presence of toxic metal cations, while the adsorption of all toxic cations from the hexa-component solution was lower than from the three-component solution containing only toxic cations. The synthesized hexadecyltrimethylammonium bentonite could be regarded as an efficient multifunctional adsorbent for the investigated type of water pollutants.

  9. Interactions between adsorbed macromolecules : measurements on emulsions and liquid films

    NARCIS (Netherlands)

    Vliet, van T.

    1977-01-01

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

  10. The use of molecular adsorbers for spacecraft contamination control

    Energy Technology Data Exchange (ETDEWEB)

    Thomson, S.; Chen, P. [NASA Goddard Space Flight Center, Greenbelt, Maryland 20771 (United States); Triolo, J.; Carosso, N. [Swales and Associates, Inc., 5050 Powder Mill Road, Beltsville, Maryland 20705 (United States)

    1996-03-01

    In recent years, the technologies associated with contamination control in space environments have grown increasingly more sophisticated, due to the ever expanding need for improving and enhancing optical and thermal control systems for spacecraft. The presence of contaminants in optical and thermal control systems can cause serious degradation of performance and/or impact the lifetime of a spacecraft. It has been a goal of the global contamination community to develop new and more effective means for controlling contamination for spacecraft. This paper describes an innovative method for controlling molecular contaminants in space environments, via the utilization of Molecular Adsorbers. It has been found that the incorporation of appropriate molecular adsorbing materials within spacecraft volumes will decrease the overall contamination level within the cavity, thereby decreasing the potential for contaminants to migrate to more critical areas. In addition, it has been found that the placement of a Molecular Adsorber at a vent location actually serves as a molecular {open_quote}{open_quote}trap{close_quote}{close_quote} for the contaminants that would have otherwise been vented into the external spacecraft environment. This paper summarizes the theory, basic design, planned applications and significant results already obtained during the investigation of using Molecular Adsorbers for spacecraft contamination control purposes. {copyright} {ital 1996 American Institute of Physics.}

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

    Science.gov (United States)

    Ball, Vincent

    2014-09-01

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

  12. Laboratory retention of vapor-phase PAHs using XAD adsorbents

    Science.gov (United States)

    Lee, James J.; Huang, Kuo-Lin; Yu, Yaochien Y.; Chen, Minsung S.

    This investigation focuses on the retention of polycyclic aromatic hydrocarbons (PAHs) on XAD (-2, -4, and -16) resins, which is crucial for estimating PAH gas/particle partition coefficients. The XAD resins were found to exhibit higher specific retention volumes ( Vg, net gas-phase retention volume per unit weight (gram) of sorbent) than PUF for some 3-ring PAHs at 20 oC. The 3-ring compounds broke through the XAD adsorbents more easily than the 4-ring compounds at constant temperature. For the equation, Log Vg= m log PL+ b ( PL: subcooled liquid vapor pressure) the average m values were approximately -0.2 and -0.3 at 20 and 40 oC, respectively. Moreover, the Vg values were lower at 40 oC than at 20 oC for each PAH compound. The XAD-4 appeared to have a greater Vg value (adsorbent weight based) for each compound among the adsorbents at 40 oC. It was possible that PAH micropore adsorption dominated on XAD-4, different from the predominance of the PAH surface adsorption on the other two adsorbents.

  13. Comparison of natural adsorbents for metal removal from acidic effluent.

    Science.gov (United States)

    Blais, J F; Shen, S; Meunier, N; Tyagi, R D

    2003-02-01

    Adsorption tests were carried out in acidic synthetic solutions (pH 2.0) using 20 g l(-1) of various natural adsorbents and 0.25 mM of 11 different metals. In decreasing order, the most efficient adsorbents tested were: oyster shells, cedar bark, vermiculite, cocoa shells and peanut shells. In contrast, weak metal adsorption was demonstrated by: red cedar wood, peat moss, pine wood, corn cobs and perlite. Metal adsorption capacities in acidic synthetic solution followed the order: Pb2+> Cr3+> Cu2+> Fe2+> Al3+> Ni2+> Cd2+ > Mn2+ > Zn2+ > Ca2+, Mg2+. Alkaline treatment (0.75 M NaOH) increased the effectiveness of metal removal for the majority of adsorbents. In contrast, acid treatment (0.75 M H2SO4) either reduced or did not affect the adsorption capacity of the materials tested. Finally, oyster shells, red cedar wood, vermiculite, cocoa shells and peanut shells, were effective natural adsorbents for the selective recovery of lead and trivalent chromium from acidic effluent.

  14. Results of testing various natural gas desulfurization adsorbents

    Science.gov (United States)

    Israelson, Gordon

    2004-06-01

    This article presents the results of testing many commercially available and some experimental sulfur adsorbents. The desired result of our testing was to find an effective method to reduce the quantity of sulfur in natural gas to less than 100 ppb volume (0.1 ppm volume). An amount of 100 ppb sulfur is the maximum limit permitted for Siemens Westinghouse solid oxide fuel cells (SOFCs). The tested adsorbents include some that rely only on physical adsorption such as activated carbon, some that rely on chemisorption such as heated zinc oxide, and some that may use both processes. The testing was performed on an engineering scale with beds larger than those used for typical laboratory tests. All tests were done at about 3.45 barg (50 psig). The natural gas used for testing was from the local pipeline in Pittsburgh and averaged 6 ppm volume total sulfur. The primary sulfur species were dimethyl sulfide (DMS), isopropyl mercaptan, tertiary butyl mercaptan, and tetrahydrothiophene. Some tests required several months to achieve a sulfur breakthrough of the bed. It was found that DMS always came through a desulfurizer bed first, independent of adsorption process. Since the breakthrough of DMS always exceeds the 100 ppb SOFC sulfur limit before other sulfurs were detected, an index was created to rate the adsorbents in units of ppm DMS × absorbent bed volume. This index is useful for calculating the expected adsorbent bed lifetime before sulfur breakthrough when the inlet natural gas DMS content is known. The adsorbents that are included in these reports were obtained from suppliers in the United States, the Netherlands, Japan, and England. Three activated carbons from different suppliers were found to have identical performance in removing DMS. One of these activated carbons was operated at four different space velocities and again showed the same performance. When using activated carbon as the basis of comparison for other adsorbents, three high-performance adsorbents

  15. Synthesis of novel porous magnetic silica microspheres as adsorbents for isolation of genomic DNA.

    Science.gov (United States)

    Zhang, Zhichao; Zhang, Liming; Chen, Lei; Chen, Ligong; Wan, Qian-Hong

    2006-01-01

    An improved procedure is described for preparation of novel mesoporous microspheres consisting of magnetic nanoparticles homogeneously dispersed in a silica matrix. The method is based on a three-step process, involving (i) formation of hematite/silica composite microspheres by urea-formaldehyde polymerization, (ii) calcination of the composite particles to remove the organic constituents, and (iii) in situ transformation of the iron oxide in the composites by hydrogen reductive reaction. The as-synthesized magnetite/silica composite microspheres were nearly monodisperse, mesoporous, and magnetizable, with as typical values an average diameter of 3.5 microm, a surface area of 250 m(2)/g, a pore size of 6.03 nm, and a saturation magnetization of 9.82 emu/g. These magnetic particles were tested as adsorbents for isolation of genomic DNA from Saccharomyces cerevisiae cells and maize kernels. The results are quite encouraging as the magnetic particle based protocols lead to the extraction of genomic DNA with satisfactory integrity, yield, and purity. Being hydrophilic in nature, the porous magnetic silica microspheres are considered a good alternative to polystyrene-based magnetic particles for use in biomedical applications where nonspecific adsorption of biomolecules is to be minimized.

  16. Removal of Cu (II and Zn (II from water with natural adsorbents from cassava agroindustry residues

    Directory of Open Access Journals (Sweden)

    Daniel Schwantes

    2015-07-01

    Full Text Available Current study employs solid residues from the processing industry of the cassava (Manihot esculenta Crantz (bark, bagasse and bark + bagasse as natural adsorbents for the removal of metal ions Cu(II and Zn(II from contaminated water. The first stage comprised surface morphological characterization (SEM, determination of functional groups (IR, point of zero charge and the composition of naturally existent minerals in the biomass. Further, tests were carried out to evaluate the sorption process by kinetic, equilibrium and thermodynamic studies. The adsorbents showed a surface with favorable adsorption characteristics, with adsorption sites possibly derived from lignin, cellulose and hemicellulose. The dynamic equilibrium time for adsorption was 60 min. Results followed pseudo-second-order, Langmuir and Dubinin-Radushkevich models, suggesting a chemisorption monolayer. The thermodynamic parameters suggested that the biosorption process of Cu and Zn was endothermic, spontaneous or independent according to conditions. Results showed that the studied materials were potential biosorbents in the decontamination of water contaminated by Cu(II and Zn(II. Thus, the above practice complements the final stages of the cassava production chain of cassava, with a new disposal of solid residues from the cassava agroindustry activity.

  17. Development of long-life-cycle tablet ceramic adsorbent for geosmin removal from water solution

    Science.gov (United States)

    Chen, Rongzhi; Xue, Qiang; Zhang, Zhenya; Sugiura, Norio; Yang, Yingnan; Li, Miao; Chen, Nan; Ying, Zhao; Lei, Zhongfang

    2011-01-01

    In this study, the tablet ceramic adsorbent (TCA), a silica/iron(III) oxide composite material, has been developed for geosmin (GSM) removal from the water solution. The physicochemical characteristics of TCA were examined with XRD, SEM, EDX and BET analyses. The sorption characteristics of GSM on TCA were investigated in a batch system. Attempts have been made to understand the adsorption kinetics, the effect of initial GSM concentration, solution pH, and reaction time. The batch experiments equilibrium data were well fitted to the Lagergren kinetic equation, which indicate the first-order nature adsorption. Over 82% of the GSM was removed by the TCA within 600 min at an initial concentration of 200 ng/L with 20 g/L of TCA dose. The batch and regeneration study indicated that the TCA is a cost-effective GSM adsorbent with sufficient mechanical strength to retain its physical integrity after long-time adsorption, and high regeneration performance for long-life-cycle application. Almost no second contamination (toxic sludge or leached iron) was observed after adsorption, and the gas resultant of thermal regeneration is harmless to atmospheric environment.

  18. Zinc peroxide nanomaterial as an adsorbent for removal of Congo red dye from waste water.

    Science.gov (United States)

    Chawla, Sneha; Uppal, Himani; Yadav, Mohit; Bahadur, Nupur; Singh, Nahar

    2017-01-01

    In the past decade, various natural byproducts, advanced metal oxide composites and photocatalysts have been reported for removal of dyes from water. Although these materials are useful for select applications, they have some limitations such as use at fixed temperature, ultra violet (UV) light and the need for sophisticated experimental set up. These materials can remove dyes up to a certain extent but require long time. To overcome these limitations, a promising adsorbent zinc peroxide (ZnO2) nanomaterial has been developed for the removal of Congo red (CR) dye from contaminated water. ZnO2 is highly efficient even in the absence of sunlight to remove CR from contaminated water upto the permissible limits set by the World Health Organization (WHO) and the United States- Environmental Protection Agency (US-EPA). The adsorbent has a specific property to adjust the pH of the test solution within 6.5-7.5 range irrespective of acidic or basic nature of water. The adsorption capacity of the material for CR dye was 208mgg(-1) within 10min at 2-10pH range. The proposed material could be useful for the industries involved in water purification. The removal of CR has been confirmed by spectroscopic and microscopic techniques. The adsorption data followed a second order kinetics and Freundlich isotherm.

  19. Hybrid materials: Magnetite-Polyethylenimine-Montmorillonite, as magnetic adsorbents for Cr(VI) water treatment.

    Science.gov (United States)

    Larraza, Iñigo; López-Gónzalez, Mar; Corrales, Teresa; Marcelo, Gema

    2012-11-01

    Hybrid materials formed by the combination of a sodium rich Montmorillonite (MMT), with magnetite nanoparticles (40 nm, Fe(3)O(4) NPs) coated with Polyethylenimine polymer (PEI 800 g/mol or PEI 25000 g/mol) were prepared. The intercalation of the magnetite nanoparticles coated with PEI among MMT platelets was achieved by cationic exchange. The resulting materials presented a high degree of exfoliation of the MMT sheets and a good dispersion of Fe(3)O(4) NPs on both the surface and among the layers of MMT. The presence of amine groups in the PEI structure not only aids the exfoliation of the MMT layers, but also gives to the hybrid material the necessary functionality to interact with heavy metals. These hybrid materials were used as magnetic sorbent for the removal of hexavalent chromium from water. The effect that pH, Cr(VI) concentration, and adsorbent material composition have on the Cr(VI) removal efficiency was studied. A complete characterization of the materials was performed. The hybrid materials showed a slight dependence of the removal efficiency with the pH in a wide range (1-9). A maximum amount of adsorption capacity of 8.8 mg/g was determined by the Langmuir isotherm. Results show that these hybrid materials can be considered as potential magnetic adsorbent for the Cr(VI) removal from water in a wide range of pH.

  20. Bisphosphonate-adsorbed ceramic nanoparticles increase bone formation in an injectable carrier for bone tissue engineering

    Directory of Open Access Journals (Sweden)

    Tegan L Cheng

    2015-10-01

    Full Text Available Sucrose acetate isobutyrate (SAIB is a sugar-based carrier. We have previously applied SAIB as a minimally invasive system for the co-delivery of recombinant human bone morphogenetic protein-2 (rhBMP-2 and found synergy when co-delivering zoledronic acid (ZA and hydroxyapatite (HA nanoparticles. Alternative bioceramics were investigated in a murine SAIB/rhBMP-2 injection model. Neither beta-tricalcium phosphate (TCP nor Bioglass (BG 45S5 had a significant effect on bone volume (BV alone or in combination with the ZA. 14C-labelled ZA binding assays showed particle size and ceramic composition affected binding with nano-HA > micro-HA > TCP > BG. Micro-HA and nano-HA increased BV in a rat model of rhBMP-2/SAIB injection (+278% and +337%, and BV was further increased with ZA–adsorbed micro-HA and nano-HA (+530% and +889%. These data support the use of ZA–adsorbed nanoparticle-sized HA as an optimal additive for the SAIB/rhBMP-2 injectable system for bone tissue engineering.

  1. 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

  2. Preparation of Urea Nitrogen Adsorbent of Complex Type and Adsorption Capacity of Urea Nitrogen onto the Adsorbent

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    The urea nitroge n adsorbent of complex type, which consists of chitosan coated dialdehyde cellulose (CDAC) and immobilized urease in gelatin membrane (IE), was prepared. The cellulose, the dialdehyde cellulose (DAC) and the CDAC were characterized by scanning electronic microscope. The results indicate that the cellulose C2-C3 bond was broken under the oxidation of periodate and it was oxidated to DAC. The DAC was coated with chitosan and the CDAC was obtained. The adsorption of urea nitrogen onto the adsorbent in Na2HPO4-NaH2PO4 buffer solution was studied in batch system. The effects of the experiment parameters, including degree of oxidation of CDAC, initial urea nitrogen concentration, pH and temperature, on the adsorption capacity of urea nitrogen onto the adsorbent at CDAC/IE weight ratio 10:1 were investigated. The results indicate that these parameters affected significantly the adsorption capacity. The adsorption capacity of urea nitrogen onto the adsorbent was 36.7 mg/g at the degree of oxidation of CDAC 88%, initial urea nitrogen concentration 600 mg/L, pH 7.4 and temperature 37 ℃.

  3. Nano porous alkaline earth metal silicates as free fatty acid adsorbents from Crude Palm Oil (CPO)

    Science.gov (United States)

    Masmur, Indra; Sembiring, Seri Bima; Bangun, Nimpan; Kaban, Jamaran; Putri, Nabila Karina

    2017-01-01

    Free fatty acids(FFA) from Crude Palm Oil (CPO) have been adsorbed by alkaline earth metal silicate (M-silicate : M = Mg, Ca, Sr and Ba) adsorbents in ethanol using batch method. The adsorbents were prepared from the chloride salts of alkaline metals and Na2SiO3. The resulting white solid of the alkaline earth metal silicates were then heated at 800°C for 3 hours to enlarge their porosities. All adsorbents were characterized by SEM-EDX, XRD and BET. The EDX spectrum of SEM-EDX showed the appearance of all elements in the adsorbents, and the XRD spectrum of all adsorbents showed that they have crystobalite structure. The porosity of the adsorbents calculated by BET method showed that the porosities of the adsorbents range from 2.0884 - 2.0969 nm. All the adsorbents were used to adsorb the FFA from CPO containing 4.79%, 7.3%, 10.37% and 13.34% of FFA. The ratio of adsorbent to CPO to be used in adsorption of FFA from CPO were made 1:1, 1:2 and 1:3, with adsorption time of 1 hour. We found that the maximum adsorption of FFA from CPO was given by Ca-Silicate adsorbent which was between 69.86 - 94.78%, while the lowest adsorption was shown by Mg-silicate adsorbent which was 49.32 -74.53%.

  4. 13C NMR and XPS characterization of anion adsorbent with quaternary ammonium groups prepared from rice straw, corn stalk and sugarcane bagasse

    Science.gov (United States)

    Cao, Wei; Wang, Zhenqian; Zeng, Qingling; Shen, Chunhua

    2016-12-01

    Despite amino groups modified crop straw has been intensively studied as new and low-cost adsorbent for removal of anionic species from water, there is still a lack of clear characterization for amino groups, especially quaternary ammonium groups in the surface of crop straw. In this study, we used 13C NMR and XPS technologies to characterize adsorbents with quaternary ammonium groups prepared from rice straw, corn stalk and sugarcane bagasse. 13C NMR spectra clearly showed the presence of quaternary ammonium groups in lignocelluloses structure of modified crop straw. The increase of nitrogen observed in XPS survey spectra also indicated the existence of quaternary ammonium group in the surface of the adsorbents. The curve fitting of high-resolution XPS N1s and C1s spectra were conducted to probe the composition of nitrogen and carbon contained groups, respectively. The results showed the proportion of quaternary ammonium group significantly increased in the prepared adsorbent's surface that was dominated by methyl/methylene, hydroxyl, quaternary ammonium, ether and carbonyl groups. This study proved that 13C NMR and XPS could be successfully utilized for characterization of quaternary ammonium modified crop straw adsorbents.

  5. Facile preparation of magnetic separable powdered-activated-carbon/Ni adsorbent and its application in removal of perfluorooctane sulfonate (PFOS) from aqueous solution.

    Science.gov (United States)

    Liang, Xuanqi; Gondal, Mohammed A; Chang, Xiaofeng; Yamani, Zain H; Li, Nianwu; Lu, Hongling; Ji, Guangbin

    2011-01-01

    The main aim of this study was to synthesize magnetic separable Nickel/powdered activated carbon (Ni/PAC) and its application as an adsorbent for removal of PFOS from aqueous solution. In this work, the synthesized adsorbent using simple method was characterized by using X-ray diffractionometer (XRD), surface area and pore size analyzer, vibrating sample magnetometer (VSM), and high resolution transmission electron microscope (HRTEM). The surface area, pore volume and pore size of synthesized PAC was 1521.8 m(2)g(-1), 0.96 cm(3)g(-1), 2.54 nm, respectively. Different kinetic models: the pseudo-first-order model, the pseudo-second-order model, and three adsorption isotherms--Langmuir, Freundlich and Temkin--were applied to study the sorption kinetics and isothermal behavior of PFOS onto the surface of an as-prepared adsorbent. The rate constant using the pseudo-second-order model for removal of 150 ppm PFOS was estimated as 8.82×10(-5) and 1.64×10(-4) for PAC and 40% Ni/PAC, respectively. Our results demonstrated that the composite adsorbents exhibited a clear magnetic hysteretic behavior, indicating the potential practical application in magnetic separation of adsorbents from aqueous solution phase as well.

  6. Layered double hydroxide-based nanomaterials as highly efficient catalysts and adsorbents.

    Science.gov (United States)

    Li, Changming; Wei, Min; Evans, David G; Duan, Xue

    2014-11-01

    Layered double hydroxides (LDHs) are a class of anion clays consisting of brucite-like host layers and interlayer anions, which have attracted increasing interest in the fields of catalysis/adsorption. By virtue of the versatility in composition, morphology, and architecture of LDH materials, as well as their unique structural properties (intercalation, topological transformation, and self-assembly with other functional materials), LDHs display great potential in the design and fabrication of nanomaterials applied in photocatalysis, heterogeneous catalysis, and adsorption/separation processes. Taking advantage of the structural merits and various control synthesis strategies of LDHs, the active center structure (e.g., crystal facets, defects, geometric and electronic states, etc.) and macro-nano morphology can be facilely manipulated for specific catalytic/adsorbent processes with largely enhanced performances. In this review, the latest advancements in the design and preparation of LDH-based functional nanomaterials for sustainable development in catalysis and adsorption are summarized.

  7. Isotope tracer study of hydrogen spillover on carbon-based adsorbents for hydrogen storage.

    Science.gov (United States)

    Lachawiec, Anthony J; Yang, Ralph T

    2008-06-17

    A composite material comprising platinum nanoparticles supported on molecular sieve templated carbon was synthesized and found to adsorb 1.35 wt % hydrogen at 298 K and 100 atm. The isosteric heat of adsorption for the material at low coverage was approximately 14 kJ/mol, and it approached a value of 10.6 kJ/mol as coverage increased for pressures at and above 1 atm. The increase in capacity is attributed to spillover, which is observed with the use of isotopic tracer TPD. IRMOF-8 bridged to Pt/C, a material known to exhibit hydrogen spillover at room temperature, was also studied with the hydrogen-deuterium scrambling reaction for comparison. The isotherms were reversible. For desorption, sequential doses of H2 and D2 at room temperature and subsequent TPD yield product distributions that are strong indicators of the surface diffusion controlled reverse spillover process.

  8. Nanofiber adsorbents for high productivity continuous downstream processing.

    Science.gov (United States)

    Hardick, Oliver; Dods, Stewart; Stevens, Bob; Bracewell, Daniel G

    2015-11-10

    An ever increasing focus is being placed on the manufacturing costs of biotherapeutics. The drive towards continuous processing offers one opportunity to address these costs through the advantages it offers. Continuous operation presents opportunities for real-time process monitoring and automated control with potential benefits including predictable product specification, reduced labour costs, and integration with other continuous processes. Specifically to chromatographic operations continuous processing presents an opportunity to use expensive media more efficiently while reducing their size and therefore cost. Here for the first time we show how a new adsorbent material (cellulosic nanofibers) having advantageous convective mass transfer properties can be combined with a high frequency simulated moving bed (SMB) design to provide superior productivity in a simple bioseparation. Electrospun polymeric nanofiber adsorbents offer an alternative ligand support surface for bioseparations. Their non-woven fiber structure with diameters in the sub-micron range creates a remarkably high surface area material that allows for rapid convective flow operations. A proof of concept study demonstrated the performance of an anion exchange nanofiber adsorbent based on criteria including flow and mass transfer properties, binding capacity, reproducibility and life-cycle performance. Binding capacities of the DEAE adsorbents were demonstrated to be 10mg/mL, this is indeed only a fraction of what is achievable from porous bead resins but in combination with a very high flowrate, the productivity of the nanofiber system is shown to be significant. Suitable packing into a flow distribution device has allowed for reproducible bind-elute operations at flowrates of 2,400 cm/h, many times greater than those used in typical beaded systems. These characteristics make them ideal candidates for operation in continuous chromatography systems. A SMB system was developed and optimised to

  9. 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.

    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...

  10. The characteristics of the FCHA for adsorbing BSA in different solvent

    Institute of Scientific and Technical Information of China (English)

    MU Rui-hong; FANG Yu; DING Ning; NIU Jing-lu; YANG Hai-ling

    2001-01-01

    @@ INTRODUCTION It has been done the researches on interaction of proteins with biomaterials. Hydroxyapatite[HA] has excellent characteristics for adsorbing and desorbing biopolymers without denaturation because of high bioaffinity and biocompatibility. Therebyit has been applied as an adsorbent.

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

    OpenAIRE

    Usenko, A. S.

    2013-01-01

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

  12. Plant waste materials from restaurants as the adsorbents for dyes

    Directory of Open Access Journals (Sweden)

    Pavlović Marija D.

    2015-01-01

    Full Text Available This paper has demonstrated the valorization of inexpensive and readily available restaurant waste containing most consumed food and beverage residues as adsorbents for methylene blue dye. Coffee, tea, lettuce and citrus waste have been utilized without any pre-treatment, thus the adsorption capacities and dye removal efficiency were determined. Coffee waste showed highest adsorbent capacity, followed by tea, lettuce and citrus waste. The dye removal was more effective as dye concentration increases from 5 up to 60 mg/L. The favorable results obtained for lettuce waste have been especially encouraged, as this material has not been commonly employed for sorption purposes. Equilibrium data fitted very well in a Freundlich isotherm model, whereas pseudo-second-order kinetic model describes the process behavior. Restaurant waste performed rapid dye removal at no cost, so it can be adopted and widely used in industries for contaminated water treatment.

  13. Dynamics in Adsorbed Homopolymer Layers: Entanglements and Osmotic Effects

    Science.gov (United States)

    Santore, Maria; Mubarekyan, Ervin

    2001-03-01

    This work seeks the dynamic mechanism for the exchange of homopolymer chains between a dilute solution and a layer adsorbed at the solid-liquid interface. With the model system of polyethylene oxide (PEO) adsorbed onto silica from aqueous solution, it is shown that the behavior of saturated interfaces compared to starved layers reveals an interesting trend: The characteristic self exchange time is dependent only on coverage, not molecular weight, for chains of 100K or less. Therefore, it is concluded that classical entanglements do not play a role below 100K. For all molecular weights, when the coverage of 0.2 mg/m2 is exceeded, the interfacial dynamics become slow. At lower coverages, chains lie flat in train, with no loops or tails, and no lateral interactions either. The onset of slow dynamics at higher coverages may be a result of both surface crowding and the resistance of loops and tails to new chains approaching the layer.

  14. Topological features of engineered arrays of adsorbates in honeycomb lattices

    Energy Technology Data Exchange (ETDEWEB)

    Gonzalez-Arraga, Luis A., E-mail: ludovici83@gmail.com [IMDEA Nanociencia, Calle de Faraday, 9, Cantoblanco, 28049 Madrid (Spain); Lado, J.L. [International Iberian Nanotechnology Laboratory (INL), Av. Mestre Jose Veiga, 4715-330 Braga (Portugal); Guinea, Francisco [IMDEA Nanociencia, Calle de Faraday, 9, Cantoblanco, 28049 Madrid (Spain); School of Physics and Astronomy, University of Manchester, Oxford Road, Manchester M13 9PL (United Kingdom)

    2016-09-01

    Hydrogen adatoms are one of the most the promising proposals for the functionalization of graphene. The adatoms induce narrow resonances near the Dirac energy, which lead to the formation of magnetic moments. Furthermore, they also create local lattice distortions which enhance the spin–orbit coupling. The combination of magnetism and spin–orbit coupling allows for a rich variety of phases, some of which have non-trivial topological features. We analyze the interplay between magnetism and spin–orbit coupling in ordered arrays of adsorbates on honeycomb lattice monolayers, and classify the different phases that may arise. We extend our model to consider arrays of adsorbates in graphene-like crystals with stronger intrinsic spin–orbit couplings. We also consider a regime away from half-filling in which the Fermi level is at the bottom of the conduction band, we find a Berry curvature distribution corresponding to a Valley–Hall effect.

  15. Modeling diffusion of adsorbed polymer with explicit solvent.

    Science.gov (United States)

    Desai, Tapan G; Keblinski, Pawel; Kumar, Sanat K; Granick, Steve

    2007-05-25

    Computer simulations of a polymer chain of length N strongly adsorbed at the solid-liquid interface in the presence of explicit solvent are used to delineate the factors affecting the N dependence of the polymer lateral diffusion coefficient, D(||). We find that surface roughness has a large influence, and D(||) scales as D(||) approximately N(-x), with x approximately 3/4 and x approximately 1 for ideal smooth and corrugated surfaces, respectively. The first result is consistent with the hydrodynamics of a "particle" of radius of gyration R(G) approximately N(nu) (nu=0.75) translating parallel to a planar interface, while the second implies that the friction of the adsorbed chains dominates. These results are discussed in the context of recent measurements.

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

    CERN Document Server

    Ankrah, S; Ramsier, R D

    2003-01-01

    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. Simple Adsorbates on Transition Metal Surfaces; A Chemical and Theoretical Approach

    Science.gov (United States)

    1992-02-26

    benzotriazole ( BTA ), 1, to inhibit corrosion. Hl’ is thought to be lost to H I H5 NI C7/ N2 1 N3C5 H3 H2 the oxide coating, which is present on...commercially available copper, through the formation of water. BTA - is proposed to bind to the surface through the nitrogen lone pairG, rather than through the...marked preference to coordinate through the nitrogen lone pair. It is, however, unclear whether BTA - lies parallel or perpendicular to the copper

  18. Selective excitation of adsorbate vibrations on dissipative surfaces

    OpenAIRE

    2008-01-01

    The selective infrared (IR) excitation of molecular vibrations is a powerful tool to control the photoreactivity prior to electronic excitation in the ultraviolet / visible (UV/Vis) light regime ("vibrationally mediated chemistry"). For adsorbates on surfaces it has been theoretically predicted that IR preexcitation will lead to higher UV/Vis photodesorption yields and larger cross sections for other photoreactions. In a recent experiment, IR-mediated desorption of molecular hydrogen from a S...

  19. 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.

  20. ADSORPTION OF PHENOL AND NITROPHENOLS ON A HYPERCROSSLINKED POLYMERIC ADSORBENT

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    The adsorption of phenol and nitrophenols on hypercrosslinked polymeric adsorbent wasstudied as a function of the solution concentration and temperature. Adsorption isotherms of phenoland nitrophenols on hypercrosslinked resin were determined. These isotherms were modeledaccording to the Freundlich adsorption isotherm. The isotherms for phenol and nitrophenols onhypercrosslinked resin were assigned as L curves. Thermodynamic parameters were calculated for allphenol and nitrophenols. The kinetics experiment results showed that the adsorption rates were of thefirst-order kinetics. The rate constants at 303K were calculated.

  1. Bonding character of lithium atoms adsorbed on a graphene layer

    OpenAIRE

    Medeiros, P.V.C.; Mota,F.B.; Mascarenhas, A.J.S.; de Castilho, C. M. C.

    2011-01-01

    Acesso restrito: Texto completo. p. 529-531. This work uses first-principles calculations to investigate the aspects of the bonding character of lithium atoms adsorbed on a graphene layer. The presented results are in contradiction to other results that have recently appeared in the specialized literature, although they confirm some previous claims. In particular, a discussion of the characteristics of the bonding between lithium and carbon atoms and whether they interact via an sp2 ...

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

    Energy Technology Data Exchange (ETDEWEB)

    Park, Jiyeon [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Jeters, Robert T. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Gill, Gary A. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Kuo, Li-Jung [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Bonheyo, George T. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States)

    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.

  3. PREPARATION OF CHITOSAN COATED METAL AFFINITY CHROMATOGRAPHY ADSORBENT

    Institute of Scientific and Technical Information of China (English)

    AanTianwei; XuWeijiang; 等

    1998-01-01

    A new and an inexpensive adsorbent of chitosan coated silica for immobilized metal affinity chromatography(IMAC) was studied.After a double coating,the chitosan coated on silica beads could be up to 53.4mg/g silica beads.When pH>3.8,the metal ligand Cu2+ was chelated on the coated chitosan with a bound capacity of 14.6mg/g chitosan without introducing iminodiacetic acid(IDA).

  4. Activity of lactoperoxidase when adsorbed on protein layers

    OpenAIRE

    Haberska, Karolina; Svensson, Olof; Shleev, Sergey; Lindh, Liselott; Arnebrant, Thomas; Ruzgas, Tautgirdas

    2008-01-01

    Lactoperoxidase (LPO) is an enzyme, which is used as an antimicrobial agent in a number of applications, e.g., food technology. In the majority of applications LPO is added to a homogeneous product phase or immobilised on product surface. In the latter case, however, the measurements of LPO activity are seldom reported. In this paperwe have assessed LPO enzymatic activity on bare and protein modified gold surfaces by means of electrochemistry. It was found that LPO rapidly adsorbs to bare gol...

  5. Fixed-bed adsorption separation of xylene isomers over sio2/silicallite-1 core-shell adsorbents

    KAUST Repository

    Khan, Easir A.

    2013-12-29

    SiO2/Silicalite-1 core-shell material has been demonstrated as potential shape selective adsorbent in gas phase separation of p-xylene from a mixture of p/o-xylene isomers. The core-shell composite comprised of large silica core and thin polycrystalline silicalite-1 shell which was synthesized via a self-assembly of silicalite-1 nanocrystals on core silica surface followed by a secondary seeded growth method. The core materials, SiO2 used in this study has mesoporosity with an average pore diameter of 60Å and hence offers no shape selectivity for xylene isomers. However, the shell, silicalite-1 contains rigid pore structures and preferentially adsorbs p-xylene from their isomers mixtures. A series of adsorption fixed bed breakthrough adsorption/desorption experiment was performed to obtain the equilibrium isotherms and adsorption isotherm parameters of xylene isomers. The equilibrium isotherms of xylene isomers follow the Langmuir\\'s model. A chromatographic adsorption model has been used to describe the fixed-bed breakthrough profiles of xylene isomers. The model has successfully predicted the responses of the binary mixtures of p/o-xylene isomers. The SiO2/silicalite-1 core-shell adsorbents have shown para-selectivity as high as 15. © Bangladesh Uni. of Engg. & Tech.

  6. Inversion of type of separation system in planar chromatography of peptides, using C18 silica-based adsorbents.

    Science.gov (United States)

    Gwarda, Radosław Ł; Aletańska-Kozak, Monika; Matosiuk, Dariusz; Dzido, Tadeusz H

    2016-04-01

    Our previous results show, that C18 silica-based adsorbents used in high-performance thin-layer chromatography (HPTLC), provide complex retention mechanism basing on various polar and nonpolar interactions. Here we present, that in chromatography of peptides, due to mixed-mode properties of these adsorbents, there is a simple way to obtain inversion of separation system type (from reversed-phase, RP, to normal-phase, NP, and vice versa). The results presented provide detailed information how to obtain inversion mentioned and reflect the extent (the type and concentration of organic solvent, the type and concentration of ion-pairing reagent in the mobile phase) of this phenomenon. We show, that the system type inversion results in significant change of selectivity of separation, which may be especially useful in 2D separation of complex samples of basic/amphoteric compounds such as peptides. This results from the fact, that C18 silica-based HPTLC adsorbents, may be used in hydrophilic interaction chromatography (HILIC) or RP chromatography, in dependence on mobile phase composition.

  7. Modeling adsorbate-induced property changes of carbon nanotubes.

    Science.gov (United States)

    Groß, Lynn; Bahlke, Marc Philipp; Steenbock, Torben; Klinke, Christian; Herrmann, Carmen

    2017-05-05

    Because of their potential for chemical functionalization, carbon nanotubes (CNTs) are promising candidates for the development of devices such as nanoscale sensors or transistors with novel gating mechanisms. However, the mechanisms underlying the property changes due to functionalization of CNTs still remain subject to debate. Our goal is to reliably model one possible mechanism for such chemical gating: adsorption directly on the nanotubes. Within a Kohn-Sham density functional theory framework, such systems would ideally be described using periodic boundary conditions. Truncating the tube and saturating the edges in practice often offers a broader selection of approximate exchange-correlation functionals and analysis methods. By comparing the two approaches systematically for NH3 and NO2 adsorbates on semiconducting and metallic CNTs, we find that while structural properties are less sensitive to the details of the model, local properties of the adsorbate may be as sensitive to truncation as they are to the choice of exchange-correlation functional, and are similarly challenging to compute as adsorption energies. This suggests that these adsorbate effects are nonlocal. © 2017 Wiley Periodicals, Inc.

  8. Distribution of metal and adsorbed guest species in zeolites

    Energy Technology Data Exchange (ETDEWEB)

    Chmelka, B.F.

    1989-12-01

    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 {sup 129}Xe NMR spectroscopy an important diagnostic probe of metal clustering and adsorbate distribution processes in zeolites. The utility of {sup 129}Xe 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, {sup 129}Xe NMR is insensitive to fine structural details at room temperature.

  9. Development Trends in Porous Adsorbents for Carbon Capture.

    Science.gov (United States)

    Sreenivasulu, Bolisetty; Sreedhar, Inkollu; Suresh, Pathi; Raghavan, Kondapuram Vijaya

    2015-11-03

    Accumulation of greenhouse gases especially CO2 in the atmosphere leading to global warming with undesirable climate changes has been a serious global concern. Major power generation in the world is from coal based power plants. Carbon capture through pre- and post- combustion technologies with various technical options like adsorption, absorption, membrane separations, and chemical looping combustion with and without oxygen uncoupling have received considerable attention of researchers, environmentalists and the stake holders. Carbon capture from flue gases can be achieved with micro and meso porous adsorbents. This review covers carbonaceous (organic and metal organic frameworks) and noncarbonaceous (inorganic) porous adsorbents for CO2 adsorption at different process conditions and pore sizes. Focus is also given to noncarbonaceous micro and meso porous adsorbents in chemical looping combustion involving insitu CO2 capture at high temperature (>400 °C). Adsorption mechanisms, material characteristics, and synthesis methods are discussed. Attention is given to isosteric heats and characterization techniques. The options to enhance the techno-economic viability of carbon capture techniques by integrating with CO2 utilization to produce industrially important chemicals like ammonia and urea are analyzed. From the reader's perspective, for different classes of materials, each section has been summarized in the form of tables or figures to get a quick glance of the developments.

  10. Adsorption isotherm of non-azeotropic solution onto porous adsorbents

    Science.gov (United States)

    Bono, A.; Ramlan, N. A.; Anisuzzaman, S. M.; Chu, C. M.; Farm, Y. Y.

    2016-06-01

    Adsorption isotherm is essential component in the understanding of the adsorption process. Several methods of the measurements, analysis and interpretation of adsorption from solution have been reported in the literature. Most of the measurements of adsorption isotherm from solution were involved the measurement of excess isotherm conducted at low region of sorbates concentration. Direct interpretation of excess adsorption isotherm as adsorption isotherm is always been practice. Therefore, in this work a study on the measurement of the adsorption isotherm from solution of non-azeotropic organic solvent mixture onto porous adsorbents for whole range of liquid concentration was conducted. The study included the measurement of excess adsorption isotherm using conventional technique. Theoretical analysis and interpretation of adsorption isotherm from the excess isotherm were conducted using Pseudo Ideal Adsorption, Gibbs Dividing Plane Model and Langmuir-Fruendlich binary isotherm model. For organic solvents, acetone and propanol were chosen as the adsorbates due to the non-azeotropic properties in the mixture. Activated carbon and silicalite were chosen as adsorbents due to the different in their porosity such as macro porous and micro porous structure. The result of the study has revealed that the adsorption isotherm of non-azeotropic mixture onto activated carbon and silicalite can be interpreted as monolayer type of adsorption.

  11. Fluctuations in the number of irreversibly adsorbed particles

    Science.gov (United States)

    Adamczyk, Zbigniew; Szyk-Warszyńska, Lilianna; Siwek, B.; Weroński, P.

    2000-12-01

    Fluctuations in the number of colloid particles adsorbed irreversibly under pure diffusion transport conditions were determined as a function of surface density and ionic strength of the suspension. The experiments were carried out for monodisperse polystyrene latex particles of micrometer size range adsorbing irreversibly at mica surface. The surface density of adsorbed particles at various areas was determined using the direct microscope observation method. A new experimental cell was used enabling in situ observations of particles adsorption under conditions of negligible gravity effects. It was found that the particle density fluctuations for high ionic strength were in a good agreement with the theoretical results derived from the random sequential adsorption (RSA) model. Also, the theoretical results stemming from the equilibrium scaled particle theory reflected the experimental data satisfactorily. For lower ionic strength a deviation from the hard sphere behavior was experimentally demonstrated. This effect due to the repulsive electrostatic interactions was interpreted in terms of the effective hard particle concept. The universal dependence of variance on particle density obtained in this way was found in a good agreement with the RSA model for all ionic strength. These results proved that fluctuations in particle density of monolayer formed under diffusional conditions differ fundamentally from these obtained under ballistic transport conditions.

  12. Amine-functionalized porous silicas as adsorbents for aldehyde abatement.

    Science.gov (United States)

    Nomura, Akihiro; Jones, Christopher W

    2013-06-26

    A series of aminopropyl-functionalized silicas containing of primary, secondary, or tertiary amines is fabricated via silane-grafting on mesoporous SBA-15 silica and the utility of each material in the adsorption of volatile aldehydes from air is systematically assessed. A particular emphasis is placed on low-molecular-weight aldehydes such as formaldehyde and acetaldehyde, which are highly problematic volatile organic compound (VOC) pollutants. The adsorption tests demonstrate that the aminosilica materials with primary amines most effectively adsorbed formaldehyde with an adsorption capacity of 1.4 mmolHCHO g(-1), whereas the aminosilica containing secondary amines showed lower adsorption capacity (0.80 mmolHCHO g(-1)) and the aminosilica containing tertiary amines adsorbed a negligible amount of formaldehyde. The primary amine containing silica also successfully abated higher aldehyde VOC pollutants, including acetaldehyde, hexanal, and benzaldehyde, by effectively adsorbing them. The adsorption mechanism is investigated by (13)C CP MAS solid-state NMR and FT-Raman spectroscopy, and it is demonstrated that the aldehydes are chemically attached to the surface of aminosilica in the form of imines and hemiaminals. The high aldehyde adsorption capacities of the primary aminosilicas in this study demonstrate the utility of amine-functionalized silica materials for reduction of gaseous aldehydes.

  13. Adsorbent synthesis of polypyrrole/TiO2 for effective fluoride removal from aqueous solution for drinking water purification: Adsorbent characterization and adsorption mechanism.

    Science.gov (United States)

    Chen, Jie; Shu, Chiajung; Wang, Ning; Feng, Jiangtao; Ma, Hongyu; Yan, Wei

    2017-06-01

    More than 20 countries are still suffering problems of excessive fluoride containing water, and greater than 8mg/L fluoride groundwater has been reported in some villages in China. In order to meet the challenge in the drinking water defluoridation engineering, a high efficiency and affinity defluoridation adsorbent PPy/TiO2 composite was designed and synthetized by in-situ chemical oxidative polymerization. Fourier Transform Infrared Spectroscopy (FTIR), X-ray diffraction Investigator (XRD), X-ray photoelectron spectroscopy (XPS), Thermogravimetric analysis (TG), N2 isotherm analysis, Scanning Electron Microscopy (SEM) and Zeta potential analysis were conducted to characterize surface and textural properties of the as-prepared PPy/TiO2, and the possibility of fluoride adsorption was carefully estimated by adsorption isotherm and kinetic studies. Characterization investigations demonstrate the uniqueness of surface and textural properties, such as suitable specific surface area and abundant positively charged nitrogen atoms (N(+)), which indicate the composite is a suitable material for the fluoride adsorption. Adsorption isotherms and kinetics follow better with Langmuir and pseudo-second-order model, respectively. The maximum adsorption capacity reaches 33.178mg/g at 25°C according to Langmuir model, and particular interest was the ability to reduce the concentration of fluoride from 11.678mg/L to 1.5mg/L for drinking water at pH of 7 within 30min. Moreover, the adsorbent can be easily recycled without the loss of adsorption capacity after six cycles, greatly highlighting its outstanding affinity to fluoride, low-cost and novel to be used in the purification of fluoride containing water for drinking. Furthermore, the adsorption mechanism was extensively investigated and discussed by FTIR investigation and batch adsorption studies including effect of pH, surface potential and thermodynamics. The adsorption is confirmed to be a spontaneous and exothermic process

  14. Structure of polymer layers adsorbed from concentrated solutions

    Science.gov (United States)

    Auvray, Loïc; Auroy, Philippe; Cruz, Margarida

    1992-06-01

    We study by neutron scattering the interfacial strucuture of poly(dimethylsiloxane) layers irreversibly adsorbed from concentrated solutions or melts. We first measure the thickness h of the layers swollen by a good solvent as a function of the chain polymerisation index N and of the polymer volume fraction in the initial solution Φ. The relation h ≈ N^{0.8}Φ^{0.3}, recently predicted from an analogy between irreversibly adsorbed layers and grafted polymer brushes, describes well our results. We can therefore deduce that there is at least one large loop of about N monomers per adsorbed chain. We also study the shape of the polymer concentration profile in the layers by measuring on two samples the polymer-solid partial structure factor, that is proportional to the Fourier transform of the profile. The model of pseudobrushes predicts a concentration decay varying with the distance of the wall z as z^{-2/5}. This power law profile accounts quantitatively for the angular variation of the polymer-solid cross structure factor but it is difficult to distinguish it without anbiguity from less singular profiles. It implies that the adsorption of PDMS onto silica is sufficiently strong and fast to quench completely the loop distribution in the initial layer. Nous étudions par diffusion de neutrons la structure interfaciale de couches de poly(diméthylsiloxane) irréversiblement adsorbées sur de la silice à partir de solutions semidiluées et de fondus. Nous mesurons d'abord l'épaisseur h des couches gonflées par un bon solvant en fonction du degré de polymérisation des chaînes N et de la fraction volumique dans la solution initiale Φ. La relation h≈ N^{0.8}Φ^{0.3} récemment prédite à partir de l'analogie entre couches irréversiblement adsorbées et brosses de polymères greffés décrit bien nos résultats. Nous en déduisons qu'il existe au moins une grande boucle d'environ N monomères par chaîne adsorbée. Nous étudions aussi la forme du profil de

  15. Adsorbent-adsorbate interactions in the adsorption of Cd(II) and Hg(II) on ozonized activated carbons.

    Science.gov (United States)

    Sánchez-Polo, M; Rivera-Utrilla, J

    2002-09-01

    The present work investigated the effect of surface oxygenated groups on the adsorption of Cd(II) and Hg(II) by activated carbon. A study was undertaken to determine the adsorption isotherms and the influence of the pH on the adsorption of each metallic ion by a series of ozonized activated carbons. In the case of Cd(II), the adsorption capacity and the affinity of the adsorbent augmented with the increase in acid-oxygenated groups on the activated carbon surface. These results imply that electrostatic-type interactions predominate in this adsorption process. The adsorption observed at solution pH values below the pH(PZC) of the carbon indicates that other forces also participate in this process. Ionic exchange between -C pi-H3O+ interaction protons and Cd(II) ions would account for these findings. In the case of Hg(II), the adsorption diminished with an increase in the degree of oxidation of the activated carbon. The presence of electron-withdrawing groups on oxidized carbons decreases the electronic density of their surface, producing a reduction in the adsorbent-adsorbate dispersion interactions and in their reductive capacity, thus decreasing the adsorption of Hg(II) on the activated carbon. At pH values above 3, the pH had no influence on the adsorption of Hg(II) by the activated carbon, confirming that electrostatic interactions do not have a determinant influence on Hg(II) adsorption.

  16. Powder-based adsorbents having high adsorption capacities for recovering dissolved metals and methods thereof

    Science.gov (United States)

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

    2016-05-03

    A powder-based adsorbent and a related method of manufacture are provided. The powder-based adsorbent includes polymer powder 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 powder-based adsorbent includes irradiating polymer powder, grafting with polymerizable reactive monomers, reacting with hydroxylamine, and conditioning with an alkaline solution. Powder-based adsorbents formed according to the present method demonstrated a significantly improved uranium adsorption capacity per unit weight over existing adsorbents.

  17. Electric field cancellation on quartz: a Rb adsorbate induced negative electron affinity surface

    CERN Document Server

    Sedlacek, J A; Rittenhouse, S T; Weck, P F; Sadeghpour, H R; Shaffer, J P

    2015-01-01

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

  18. Comparative study of calcium alginate, activated carbon, and their composite beads on methylene blue adsorption.

    Science.gov (United States)

    Hassan, A F; Abdel-Mohsen, A M; Fouda, Moustafa M G

    2014-02-15

    Three adsorbents, calcium alginate beads (AB), sodium hydroxide activated carbon based coconut shells (C), and calcium alginate/activated carbon composite beads (ACB) were prepared. Their textural properties were characterized by N2-adsorption at -196°C and scanning electron microscopy. The porosity, surface area and total pore volume of C>ACB>AB, but AB adsorbent was more acidic function groups more than the other adsorbents. Adsorption experiments were conducted to examine the effects of adsorbent dosage, pH, time, temperature and initial concentration of methylene blue. Methylene blue adsorption on C, AB and ACB was observed at pH>6 to avoid the competition of H(+). The amount of dye adsorbed increases as the adsorbent dosage increase. Adsorption of dye follows pseudo-second order mechanism. Thermodynamic studies show spontaneous and endothermic nature of the overall adsorption process.

  19. Synthesis of nickel sulfide nanoparticles loaded on activated carbon as a novel adsorbent for the competitive removal of Methylene blue and Safranin-O.

    Science.gov (United States)

    Ghaedi, M; Pakniat, M; Mahmoudi, Z; Hajati, S; Sahraei, R; Daneshfar, A

    2014-04-05

    Nickel sulfide nanoparticle-loaded activated carbon (NiS-NP-AC) were synthesized as a novel adsorbent for simultaneous and rapid adsorption of Methylene blue (MB) and Safranin-O (SO), as most together compounds in wastewater. NiS-NP-AC was characterized using different techniques such as UV-visible, Fourier transform infrared spectroscopy (FTIR), energy-dispersive X-ray spectroscopy (EDX), X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM) and Brunauer-Emmett-Teller (BET). The surface area of the adsorbent was found to be very high (1018m(2)/g according BET). By using central composite design (CCD), the effects of variables such as pH, adsorbent dosage, MB concentration, SO concentration and contact time on binary dyes removal were examined and optimized values were found to be 8.1, 0.022g, 17.8mg/L, and 5mg/L and 5.46min, respectively. The very short time required for the dyes removal makes this novel adsorbent as a promising tool for wastewater treatment applications. Different models were applied to analyze experimental isotherm data. Modified-extended Langmuir model showed good fit to equilibrium data with maximum adsorption capacity at 0.022g of adsorbent. An empirical extension of competitive modified-extended Langmuir model was proposed to predict the simultaneous adsorption behavior of MB and SO. Kinetic models were applied to fit the experimental data at various adsorbent dosages and initial dyes concentrations. It was seen that pseudo-second-order equation is suitable to fit the experimental data. Individual removalof each dye was also studied.

  20. Properties of competitively adsorbed BSA and fibrinogen from their mixture on mixed and hybrid surfaces

    Science.gov (United States)

    Pandey, Lalit M.; Pattanayek, Sudip K.

    2013-01-01

    We have studied the adsorption of BSA and fibrinogen from their mixture onto surfaces with mixed self-assembled monolayer (SAM) of amine and octyl (ratio 1:1) and hybrid SAM. The properties of adsorbed proteins obtained from individual protein solution differ considerably from the properties of the adsorbed proteins obtained from mixture of proteins at same total concentration. The adsorbed amount of proteins is lesser and the adsorbed protein is more elastic if it is adsorbing from mixture of proteins. It is found that with increasing total protein concentration, adsorbed amount increases and elasticity of the adsorbed proteins decreases. The apparent displacements of BSA with Fb are observed on the graphs of change in frequency with time, which are obtained from quartz crystal microbalance.

  1. Adsorption of Heavy Metal Ions by Adsorbent from Waste Mycelium Chitin

    Institute of Scientific and Technical Information of China (English)

    苏海佳; 王丽娟; 等

    2002-01-01

    The adsorption properties of chitin adsorbent from mycelium of fermentation industries for the removal of heavy metal ions were studied.The result shows that the chitin adsorbent has high adsorption capacity for many heavy metal ions and Ni2+ in citric acid.The influence of pH was significant:When pH is higher than 4.0,the high adsorption capacity is obtained.otherwise H+ ion inhibits the adsorption of heavy metal ions.The comparison of the chitin adsorbent with some other commercial adsorbents was made,in which that the adsorption behavior of chitin adsorbent is close to that of commercial cation exchange adsorbents,and its cost is much lower than those commercial adsorbents.

  2. Description of adsorption equilibrium of PAHs on hypercrosslinked polymeric adsorbent using Polanyi potential theory

    Institute of Scientific and Technical Information of China (English)

    LONG Chao; LI AiMin; HU DaBo; LIU FuQiang; ZHANG QuanXing

    2008-01-01

    In this research, static adsorption of three polycyclic aromatic hydrocarbons (PAHs), naphthalene, acenaphthene, and fluorene, from aqueous solutions onto hypercrosslinked polymeric adsorbent within the temperature range of 288-308 K is investigated. Several isotherm equations are correlated with the equilibrium data, and the experimental data is found to fit the Polanyi-Dubinin-Manes model best within the entire range of concentrations, providing evidence that pore-filling is the dominating sorption mechanism for PAHs. The study shows that the molecular size of adsorbates has distinct in-fluence on adsorption capacity of hypercrosslinked polymeric adsorbent for the PAHs; the larger the adsorbate molecular size, the lower the adsorption equilibrium capacity. Based on the Polanyi-Dubinin-Manes model, the molecular size of adsorbates was introduced to adjust the adsorbate molar volume. Plots of qv vs. (σε/Vs) are collapsed to a single correlation curve for different adsorbates on hypercrosslinked polymeric resin.

  3. Modification of a magnetic carbon composite for ciprofloxacin adsorption.

    Science.gov (United States)

    Mao, Haixin; Wang, Shikui; Lin, Jian-Ying; Wang, Zengshuang; Ren, Jun

    2016-11-01

    A magnetic carbon composite, Fe3O4/C composite, was fabricated by one-step hydrothermal synthesis, modified by heat treatment under an inert atmosphere (N2), and then used as an adsorbent for ciprofloxacin (CIP) removal. Conditions for the modification were optimized according to the rate of CIP removal. The adsorbent was characterized by Fourier transform infrared spectroscopy, X-ray diffraction measurements, vibrating-sample magnetometry, scanning electron microscopy, transmission electron microscopy, and N2 adsorption/desorption isotherm measurements. The results indicate that the modified adsorbent has substantial magnetism and has a large specific area, which favor CIP adsorption. The effects of solution pH, adsorbent dose, contact time, initial CIP concentration, ion strength, humic acid and solution temperature on CIP removal were also studied. Our results show that all of the above factors influence CIP removal. The Langmuir adsorption isotherm fits the adsorption process well, with the pseudo second-order model describing the adsorption kinetics accurately. The thermodynamic parameters indicate that adsorption is mainly physical adsorption. Recycling experiments revealed that the behavior of adsorbent is maintained after recycling for five times. Overall, the modified magnetic carbon composite is an efficient adsorbent for wastewater treatment.

  4. A DFT study of halogen atoms adsorbed on graphene layers

    Energy Technology Data Exchange (ETDEWEB)

    Medeiros, Paulo V C; De Brito Mota, F; De Castilho, Caio M C [Grupo de Fisica de Superfcies e Materiais, Instituto de Fisica, Universidade Federal da Bahia, Campus Universitario da Federacao/Ondina, 40170-115 Salvador, Bahia (Brazil); Mascarenhas, Artur J S, E-mail: caio@ufba.br [Instituto Nacional de Ciencia e Tecnologia em Energia e Ambiente-INCT-E and A, Universidade Federal da Bahia, 40170-280 Salvador, Bahia (Brazil)

    2010-12-03

    In this work, ab initio density functional theory calculations were performed in order to study the structural and electronic properties of halogens (X = fluorine, chlorine, bromine or iodine) that were deposited on both sides of graphene single layers (X-graphene). The adsorption of these atoms on only one side of the layer with hydrogen atoms adsorbed on the other was also considered (H,X-graphene). The results indicate that the F-C bond in the F-graphene system causes an sp{sup 2} to sp{sup 3} transition of the carbon orbitals, and similar effects seem to occur in the H,X-graphene systems. For the other cases, two configurations are found: bonded (B) and non-bonded (NB). For the B configuration, the structural arrangement of the atoms was similar to F-graphene and H-graphene (graphane), although the electronic structures present some differences. In the NB configuration, the interaction between the adsorbed atoms and the graphene layer seems to be essentially of the van der Waals type. In these cases, the original shape of the graphene layer presents only small deviations from the pristine form and the adsorbed atoms reach equilibrium far from the sheet. The F-graphene structure has a direct bandgap of approximately 3.16 eV at the {Gamma} point, which is a value that is close to the value of 3.50 eV that was found for graphane. The Cl-graphene (B configuration), H,F-graphene and H,Cl-graphene systems have smaller bandgap values. All of the other systems present metallic behaviours. Energy calculations indicate the possible stability of these X-graphene layers, although some considerations about the possibility of spontaneous formation have to be taken into account.

  5. Use of Drinking Water Sludge as Adsorbent for H2S Gas Removal from Biogas

    Directory of Open Access Journals (Sweden)

    Sucheela Polruang

    2017-01-01

    Full Text Available This paper reports the results of a research project, which attempts to produce a low-cost adsorbent material from waste (drinking water sludge. The main objective of this work is to study the characteristics of drinking water sludge for its adsorptive properties including morphology, surface area, porosity and chemical composition. The effect of activation conditions on H2S gas adsorption efficiency of drinking water sludge was experimented. In this study, raw drinking water sludge was divided into 3 groups. In the first group, drinking water sludge was only oven dried at 105°C. For the other 2 groups, drinking water sludge was soaked in 2.5 M NaOH solution. After soaking, the sludge was divided into 2 groups (group 2 and 3. The second group was washed with distilled water until pH 7; while the third group was not. Biogas from a swine farm was used with an initial H2S gas concentration in the range of 2,000 - 4,000 ppm. The material analysis showed that more surface area and total volume of sludge can be obtained after activated with NaOH. From the adsorption experiments, it was found that the highest adsorption capacity (qe of 87.94 mg H2S/g adsorptive material can be achieved by using sludge from the third group. Moreover, by adding of 20 wt% iron filing into sludge of the third group the adsorption capacity increased to 105.22 mg H2S/g adsorptive material. Drinking water sludge can be considered as a high potential energy saving and low cost adsorbent for removal of H2S.

  6. Graphene symmetry-breaking with molecular adsorbates: modeling and experiment

    Science.gov (United States)

    Groce, M. A.; Hawkins, M. K.; Wang, Y. L.; Cullen, W. G.; Einstein, T. L.

    2012-02-01

    Graphene's structure and electronic properties provide a framework for understanding molecule-substrate interactions and developing techniques for band gap engineering. Controlled deposition of molecular adsorbates can create superlattices which break the degeneracy of graphene's two-atom unit cell, opening a band gap. We simulate scanning tunneling microscopy and spectroscopy measurements for a variety of organic molecule/graphene systems, including pyridine, trimesic acid, and isonicotinic acid, based on density functional theory calculations using VASP. We also compare our simulations to ultra-high vacuum STM and STS results.

  7. Detection of adsorbed water and hydroxyl on the Moon.

    Science.gov (United States)

    Clark, Roger N

    2009-10-23

    Data from the Visual and Infrared Mapping Spectrometer (VIMS) on Cassini during its flyby of the Moon 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 Moon. 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.

  8. Improved phenol adsorption from aqueous solution using electrically conducting adsorbents

    Energy Technology Data Exchange (ETDEWEB)

    Asghar, Hafiz Muhammad Anwaar; Hussain, Syed Nadir [The University of Manchester, Manchester (United Kingdom); Sattar, Hamed [University of Leeds, Leeds (United Kingdom); Brown, Nigel Willis [Daresbury Innovation Centre, Cheshire (United Kingdom); Roberts, Edward Pelham Lindfield [University of Calgary, Calgary (Canada)

    2014-05-15

    The electrically conducting and partially porous graphite based adsorbent (called Nyex{sup TM} 2000) was tested for its adsorption capacity and electrochemical regeneration ability for the removal of phenol from aqueous solution. Nyex{sup TM} 2000 was tested in comparison with Nyex{sup TM} 1000, which is currently being used for a number of industrial waste water treatment applications. Nyex{sup TM} 1000 exhibited small adsorption capacity of 0.1 mg g{sup -1} for phenol because of having small specific surface area of 1 m{sup 2} g{sup -1}. In contrast, Nyex{sup TM} 2000 with specific surface area of 17 m{sup 2} g{sup -1} delivered an adsorption capacity of 0.8 mg g{sup -1}, which was eight-fold higher than that of Nyex{sup TM} 1000. Nyex{sup TM} 2000 was successfully electrochemically regenerated by passing a current of 0.5 A, charge passed of 31 C g{sup -1} for a treatment time of 45 minutes. These electrochemical parameters were comparable to Nyex{sup TM} 1000 for which a current of 0.5 A, charge passed of 5 C g{sup -1} for a treatment time of 20 minutes were applied for complete oxidation of adsorbed phenol. The comparatively high charge density was found to be required for Nyex{sup TM} 2000, which is justified with its higher adsorption capacity. The FTIR results validated the mineralization of adsorbed phenol into CO{sub 2} and H{sub 2}O except the formation of few by-products, which were in traces when compared with the concentration of phenol removed from aqueous solution. The electrical energy as required for electrochemical oxidation of phenol adsorbed onto Nyex{sup TM} 1000 and 2000 was found to be 214 and 196 J mg{sup -1}, respectively. The comparatively low energy requirement for electrochemical oxidation using Nyex{sup TM} 2000 is consistent with its higher bed electrical conductivity, which is twice that of Nyex{sup TM} 1000.

  9. 3,5-Dichlorophenol Removal From Wastewater Using Alternative Adsorbents

    Science.gov (United States)

    Kobetičová, Hana; Lipovský, Marek; Wachter, Igor; Soldán, Maroš

    2015-06-01

    The main objective of this paper is to evaluate the efficiency of 3,5-dichlorophenol removal from wastewater by using alternative low cost adsorbents. Waste from the production and processing of metals (black nickel mud, red mud) and a biosorbent (Lemna minor) were used for this research. Initial concentration of the contaminant was 4 mmol L-1, the contact time of sorbent and waste water was 0 - 48 hrs and the temperature during experiment was 25 ± 0.2 °C. The results show that the highest removal efficiency of 3,5 - dichlorophenol (58.18 %) was reached by the red mud in 48 hours.

  10. 3,5-Dichlorophenol Removal From Wastewater Using Alternative Adsorbents

    Directory of Open Access Journals (Sweden)

    Kobetičová Hana

    2015-06-01

    Full Text Available The main objective of this paper is to evaluate the efficiency of 3,5-dichlorophenol removal from wastewater by using alternative low cost adsorbents. Waste from the production and processing of metals (black nickel mud, red mud and a biosorbent (Lemna minor were used for this research. Initial concentration of the contaminant was 4 mmol L−1, the contact time of sorbent and waste water was 0 - 48 hrs and the temperature during experiment was 25 ± 0.2 °C. The results show that the highest removal efficiency of 3,5 - dichlorophenol (58.18 % was reached by the red mud in 48 hours.

  11. Magnetically modified microbial cells: A new type of magnetic adsorbents

    Institute of Scientific and Technical Information of China (English)

    Ivo; Safarik; Mirka; Safarikova

    2007-01-01

    Microbial cells, either in free or immobilized form, can be used for the preconcentration or removal of metal ions, organic and inorganic xenobiotics or biologically active compounds. Magnetic modification of these cells enables to prepare magnetic adsorbents that can be easily manipulated in difficult-to-handle samples, such as suspensions, in the presence of external magnetic field. In this review, typical examples of magnetic modifications of microbial cells are presented, as well as their possible applications for the separation of organic xenobiotics and heavy metal ions.

  12. Structure of adsorbed monolayers. The surface chemical bond

    Energy Technology Data Exchange (ETDEWEB)

    Somorjai, G.A.; Bent, B.E.

    1984-06-01

    This paper attempts to provide a summary of what has been learned about the structure of adsorbed monolayers and about the surface chemical bond from molecular surface science. While the surface chemical bond is less well understood than bonding of molecules in the gas phase or in the solid state, our knowledge of its properties is rapidly accumulating. The information obtained also has great impact on many surface science based technologies, including heterogeneous catalysis and electronic devices. It is hoped that much of the information obtained from studies at solid-gas interfaces can be correlated with molecular behavior at solid-liquid interfaces. 31 references, 42 figures, 1 table.

  13. Electrically heated particulate filter regeneration using hydrocarbon adsorbents

    Science.gov (United States)

    Gonze, Eugene V [Pinckney, MI

    2011-02-01

    An exhaust system that processes exhaust generated by an engine is provided. The system generally includes a particulate filter (PF) that filters particulates from the exhaust wherein an upstream end of the PF receives exhaust from the engine. A grid of electrically resistive material selectively heats exhaust passing through the upstream end to initiate combustion of particulates within the PF. A hydrocarbon adsorbent coating applied to the PF releases hydrocarbons into the exhaust to increase a temperature of the combustion of the particulates within the PF.

  14. Behavior of adsorbed Poly-A onto sodium montmorillonite

    Energy Technology Data Exchange (ETDEWEB)

    Palomino-Aquino, Nayeli [Facultad de Estudios Superiores Iztacala, Universidad Nacional Autónoma de México (Mexico); Negrón-Mendoza, Alicia, E-mail: negron@nucleares.unam.mx [Instituto de Ciencias Nucleares, Universidad Nacional Autónoma de México (Mexico)

    2015-07-23

    The adsorption of Poly-A (a polynucleotide consisting of adenine, ribose and a phosphate group), onto a clay mineral, was studied to investigate the extent of adsorption, the site of binding, and the capacity of the clay to protect Poly-A, while it is adsorbed onto the clay, from external sources of energy. The results showed that Poly-A presented a high percentage of adsorption at the edges of the clay and that the survival of the polynucleotide was superior to irradiating the polymer in the absence of the clay.

  15. Temperature programmed desorption of weakly bound adsorbates on Au(111)

    Science.gov (United States)

    Engelhart, Daniel P.; Wagner, Roman J. V.; Meling, Artur; Wodtke, Alec M.; Schäfer, Tim

    2016-08-01

    We have performed temperature programmed desorption (TPD) experiments to analyze the desorption kinetics of Ar, Kr, Xe, C2H2, SF6, N2, NO and CO on Au(111). We report desorption activation energies (Edes), which are an excellent proxy for the binding energies. The derived binding energies scale with the polarizability of the molecules, consistent with the conclusion that the surface-adsorbate bonds arise due to dispersion forces. The reported results serve as a benchmark for theories of dispersion force interactions of molecules at metal surfaces.

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

    Directory of Open Access Journals (Sweden)

    Kobetičová Hana

    2014-12-01

    Full Text Available 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.

  17. Sustainable catalyst supports for carbon dioxide gas adsorbent

    Science.gov (United States)

    Mazlee, M. N.

    2016-07-01

    The adsorption of carbon dioxide (CO2) become the prime attention nowadays due to the fact that increasing CO2 emissions has been identified as a contributor to global climate change. Major sources of CO2 emissions are thermoelectric power plants and industrial plants which account for approximately 45% of global CO2 emissions. Therefore, it is an urgent need to develop an efficient CO2 reduction technology such as carbon capture and storage (CCS) that can reduce CO2 emissions particularly from the energy sector. A lot of sustainable catalyst supports have been developed particularly for CO2 gas adsorbent applications.

  18. Controllable Catalysis with Nanoparticles: Bimetallic Alloy Systems and Surface Adsorbates

    KAUST Repository

    Chen, Tianyou

    2016-05-16

    Transition metal nanoparticles are privileged materials in catalysis due to their high specific surface areas and abundance of active catalytic sites. While many of these catalysts are quite useful, we are only beginning to understand the underlying catalytic mechanisms. Opening the “black box” of nanoparticle catalysis is essential to achieve the ultimate goal of catalysis by design. In this Perspective we highlight recent work addressing the topic of controlled catalysis with bimetallic alloy and “designer” adsorbate-stabilized metal nanoparticles.

  19. FTIR spectroscopy combined with quantum chemical calculations to investigate adsorbed nitrate on aluminium oxide surfaces in the presence and absence of co-adsorbed water.

    Science.gov (United States)

    Baltrusaitis, Jonas; Schuttlefield, Jennifer; Jensen, Jan H; Grassian, Vicki H

    2007-09-28

    Surface reactions of nitrogen oxides with aluminium oxide particles result in the formation of adsorbed nitrate. Specifically, when alpha-Al(2)O(3) and gamma-Al(2)O(3) particles are exposed to gas-phase NO(2) and HNO(3) adsorbed nitrate forms on the surface. In this study, Fourier transform infrared (FTIR) spectroscopy is combined with quantum chemical calculations to further our understanding of the adsorbed nitrate product on aluminium oxide particle surfaces in the presence and absence of co-adsorbed water at 296 K. FTIR spectra of adsorbed nitrate on alpha-Al(2)O(3) and gamma-Al(2)O(3) particles are interpreted using calculated vibrational frequencies of nitrate coordinated to binuclear Al oxide cluster models. Comparison of the calculated and experimental vibrational frequencies of adsorbed nitrate establishes different modes of coordination (monodentate, bidentate and bridging) of the nitrate ion to the surface in the absence of adsorbed water. In the presence of co-adsorbed water, the nitrate ion becomes fully solvated, as shown by a comparison of the experimental nitrate infrared spectra as a function of relative humidity with the calculated nitrate vibrational frequencies for binuclear Al cluster compounds which contain both coordinated nitrate ions and water molecules. These calculations also suggest that adsorbed water can displace nitrate from direct coordination to the surface, leading to an outer-sphere nitrate adsorption complex as well as an inner-sphere complex. Furthermore, the relative humidity dependence of the spectra suggest that water does not evenly wet the surface even at high relative humidity, as there are open or bare surface sites where nitrate ions are not solvated. Besides adsorbed mondendate, bidendate, bridging and solvated nitrate, the presence of ion bound nitrate ion, partially solvated nitrate, molecular nitric acid, hydronium ion and H(3)O(+):NO(3)(-) ion pairs on the oxide surface are also discussed.

  20. 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.

  1. Evaluation of Adsorbed Arsenic and Potential Contribution to Shallow Groundwater in Tulare Lake Bed Area, Tulare Basin, California

    Science.gov (United States)

    Gao, S.; Fujii, R.; Chalmers, A.T.; Tanji, K.K.

    2004-01-01

    Elevated As concentrations in shallow groundwater in parts of the Tulare Basin, California, are a concern because of potential migration into deeper aquifers that could serve as a source of future drinking water. The objectives of this study were to evaluate adsorbed As and the potential contribution to groundwater using (i) isotopic dilution, (ii) successive extraction with an electrolyte solution resembling the pore-water chemical composition, and (iii) PO4 exchange for As. Sediment samples collected from 2 to 4 m below land surface in the Tulare Lake bed area contained a total As concentration of 24 mg As kg-1. Pore water extracted under hydraulic pressure contained a total As concentration of 590 ??g As L-1, which predominantly contained As as arsenate [As(V), 97%], a minor amount of arsenite [As(III), 3%], and non-detectable organic As. The isotopic dilution method [73As(V)] estimated that the concentration of adsorbed As(V) on the sediment was 5.7 mg As kg-1 at pH 8.5 and 6.7 mg As kg-1 at pH 7.5, respectively. Fourteen successive 24-h extractions with the artificial pore water released up to 57 to 61% of the adsorbed As(V) that was determined by isotopic dilution, indicating that only a portion of the adsorbed As could be released to groundwater. The phosphate-exchangeable As (0.1 M PO4, pH 8.5 or 7.5) was 63% of the isotopically exchangeable As(V). Thus, extraction of As by 0.1 M PO4 at ambient pHs is recommended as a method to determine the potential amount of As(V) on sediments that could be released to the solution phase. The overall results indicated that adsorbed As could be a significant source of As to groundwater. However, other factors that affect As transport such as the leaching rate need to be considered.

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

    Energy Technology Data Exchange (ETDEWEB)

    Tallent, O.K.; Mailen, J.C.; Pannell, K.D.

    1984-06-01

    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 HNO/sub 3/, dibutyl phosphate (DBP), UO/sub 2//sup 2 +/, Pu/sup 4 +/, 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 NaNO/sub 3/ waste generated per metric ton of nuclear fuel reprocessed would be reduced significantly. 19 references, 6 figures, 12 tables.

  3. Structure of Inert Gases Adsorbed in MCM-41

    Science.gov (United States)

    Evans, Dylan; Sokol, Paul

    One-dimensional quantum liquids of 3He or 4He have generated recent interest for investigation in the Luttinger liquid model. Unfortunately, current studies lack a clear demonstration of definitively one-dimensional behavior. We propose using the templated, porous material, MCM-41, as a host for an atomic Luttinger liquid. In general, the pores of MCM-41 are too wide to provide a strictly one-dimensional environment, so we investigate preplating these pores with inert gases to effectively reduce their diameter. We present the results of studies of the structure of inert gases in MCM-41. Nitrogen sorption isotherms were used to characterize the sample. Then, using inert gases as adsorbates, we determined the minimum effective pore diameter that can be achieved in our sample before capillary condensation takes over. X-ray powder diffraction (XRD) was performed on the ideally preplated sample to investigate the structure of the adsorbates in the nanopores. The XRD measurements are compared to simulations of core-shell cylinder model scattering, and the validity of the model is assessed. The prospects for creating a definitively one-dimensional channel for the application of studying the structure and dynamics of helium confined in one dimension are discussed. This work was supported by the National Science Foundation under Grant DGE-1069091.

  4. 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.

  5. 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...

  6. Heterogeneous radiolysis of HCN adsorbed on a solid surface

    Energy Technology Data Exchange (ETDEWEB)

    Colin-Garcia, M.; Ortega-Gutierrez, F. [Instituto de Geologia, Universidad Nacional Autonoma de Mexico, Ciudad Universitaria, 04510 Mexico D.F. (Mexico); Ramos-Bernal, S. [Instituto de Ciencias Nucleares, Universidad Nacional Autonoma de Mexico, Ciudad Universitaria, 04510 Mexico D.F. (Mexico); Negron-Mendoza, A., E-mail: negron@nucleares.unam.m [Instituto de Ciencias Nucleares, Universidad Nacional Autonoma de Mexico, Ciudad Universitaria, 04510 Mexico D.F. (Mexico)

    2010-07-21

    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 (CO{sub 2}, NH{sub 4}, 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.

  7. 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 (ΔG0 0, ΔS0 > 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.

  8. Cellulose: A review as natural, modified and activated carbon adsorbent.

    Science.gov (United States)

    Suhas; Gupta, V K; Carrott, P J M; Singh, Randhir; Chaudhary, Monika; Kushwaha, Sarita

    2016-09-01

    Cellulose is a biodegradable, renewable, non-meltable polymer which is insoluble in most solvents due to hydrogen bonding and crystallinity. Natural cellulose shows lower adsorption capacity as compared to modified cellulose and its capacity can be enhanced by modification usually by chemicals. This review focuses on the utilization of cellulose as an adsorbent in natural/modified form or as a precursor for activated carbon (AC) for adsorbing substances from water. The literature revealed that cellulose can be a promising precursor for production of activated carbon with appreciable surface area (∼1300m(2)g(-1)) and total pore volume (∼0.6cm(3)g(-1)) and the surface area and pore volume varies with the cellulose content. Finally, the purpose of review is to report a few controversies and unresolved questions concerning the preparation/properties of ACs from cellulose and to make aware to readers that there is still considerable scope for future development, characterization and utilization of ACs from cellulose.

  9. Palladium dimers adsorbed on graphene: A DFT study

    Energy Technology Data Exchange (ETDEWEB)

    Kaur, Gagandeep, E-mail: gaganj1981@yahoo.com [Department of Physics and Centre of Advanced Studies in Physics, Panjab University, Chandigarh-160014 (India); Chandigarh Engineering College, Landran, Mohali, Punjab (India); Gupta, Shuchi, E-mail: sgupta@pu.ac.in [University Institute of Engineering and Technology, Panjab University, Chandigarh -160014 (India); Dharamvir, Keya, E-mail: keya@pu.ac.in [Department of Physics and Centre of Advanced Studies in Physics, Panjab University, Chandigarh-160014 (India)

    2015-05-15

    The 2D structure of graphene shows a great promise for enhanced catalytic activity when adsorbed with palladium. We performed a systematic density functional theory (DFT) study of the adsorption of palladium dimer (Pd{sub 2}) on graphene using SIESTA package, in the generalized gradient approximation (GGA). The adsorption energy, geometry, and charge transfer of Pd{sub 2}-graphene system are calculated. Both horizontal and vertical orientations of Pd{sub 2} on graphene are studied. Our calculations revealed that the minimum energy configuration for Pd dimer is parallel to the graphene sheet with its two atoms occupying centre of adjacent hexagonal rings of graphene sheet. Magnetic moment is induced for Pd dimer adsorbed on graphene in vertical orientation while horizontal orientation of Pd dimer on graphene do not exhibit magnetism. Insignificant energy differences among adsorption sites means that dimer mobility on the graphene sheet is high. There is imperceptible distortion of graphene sheet perpendicular to its plane. However, some lateral displacements are seen.

  10. Dynamics of different molecules adsorbed in porous media

    Indian Academy of Sciences (India)

    S Mitra; V S Kamble; A K Tripathi; N M Gupta; R Mukhopadhyay

    2004-08-01

    We present in this paper a comparative study on the dynamics of benzene, cyclohexane, and methanol molecules, confined in the pores of MCM-41 molecular sieve and HZSM-5 zeolite. The quasi-elastic neutron scattering (QENS) measurements revealed that the physical state of these adsorbed molecules depended not only on the structural characteristics of the host matrix but also on the chemical properties, such as dipole moment, of the guest molecules. Thus, while no motion was observed in the time-scale of 10−10 –10−12 s in the case of methanol, the larger size benzene and cyclohexane molecules are found to perform six-fold and three-fold jump rotation, respectively, when adsorbed inside the cages of HZSM-5 at room temperature. At the same time, all the three molecules are found to undergo a translational motion inside the pores of MCM-41 molecular sieves, the value of diffusion constant being the lowest in case of methanol because of its higher polarity. Translationl motion of the guest molecules inside the pores of MCM-41 can be satisfactorily described by Chudley–Eliott fixed jump length diffusion and accordingly the residence time, jump length and diffusion constant are estimated.

  11. Membrane adsorbers as purification tools for monoclonal antibody purification.

    Science.gov (United States)

    Boi, Cristiana

    2007-03-15

    Downstream purification processes for monoclonal antibody production typically involve multiple steps; some of them are conventionally performed by bead-based column chromatography. Affinity chromatography with Protein A is the most selective method for protein purification and is conventionally used for the initial capturing step to facilitate rapid volume reduction as well as separation of the antibody. However, conventional affinity chromatography has some limitations that are inherent with the method, it exhibits slow intraparticle diffusion and high pressure drop within the column. Membrane-based separation processes can be used in order to overcome these mass transfer limitations. The ligand is immobilized in the membrane pores and the convective flow brings the solute molecules very close to the ligand and hence minimizes the diffusional limitations associated with the beads. Nonetheless, the adoption of this technology has been slow because membrane chromatography has been limited by a lower binding capacity than that of conventional columns, even though the high flux advantages provided by membrane adsorbers would lead to higher productivity. This review considers the use of membrane adsorbers as an alternative technology for capture and polishing steps for the purification of monoclonal antibodies. Promising industrial applications as well as new trends in research will be addressed.

  12. Fibrous adsorbent for removal of aqueous aromatic hydrocarbons.

    Science.gov (United States)

    Jung, Yong-Jun; Kiso, Yoshiaki; Oguchi, Tatsuo; Yamada, Toshiro; Takagi, Hiroo; Nishimura, Kazuyuki

    2007-01-01

    Bundles of a strongly hydrophobic fibrous material (p-phenylene-2,6-benzobisoxazole; PBO; Zylon) were employed as an adsorbent for the removal of aqueous aromatic compounds, because the PBO fibers are too rigid to be woven and did not entrap suspended solids. The removal performance for nine kinds of polyaromatic hydrocarbons (PAHs) and di-(2-ethylhexyl) phthalate (DEHP) was evaluated. PAHs and DEHP at initial concentrations of 50 microg L(-1) were removed at 72.5-99.9% and ca. 95%, respectively, although the removal efficiencies were affected by the phase ratio (fiber weight/solution volume). The logarithm of the partition coefficient (log K) for planar PAHs was linearly correlated with the logarithm of the n-octanol/water partition coefficient (log P), but nonplanar PAHs, such as cis-stilbene, p-terphenyl, and o-terphenyl, showed significantly lower adsorption performance. The adsorbed PAHs were not desorbed effectively with CH3CN, CH2Cl2, and toluene. On the other hand, DEHP was effectively desorbed with methanol.

  13. Application of 1H NMR spectroscopy method for determination of characteristics of thin layers of water adsorbed on the surface of dispersed and porous adsorbents.

    Science.gov (United States)

    Turov, V V; Leboda, R

    1999-02-01

    The paper presents 1H NMR spectroscopy as a perspective method of the studies of the characteristics of water boundary layers in the hydrated powders and aqueous dispergated suspensions of the adsorbents. The method involves measurements of temperature dependence proton signals intensity in the adsorbed water at temperatures lower than 273 K. Free energy of water molecules at the adsorbent/water interface is diminished due to the adsorption interactions causing the water dosed to the adsorbent surface freezes at T water can be determined from the intensity of the water signal of 1H NMR during the freezing-thawing process. Due to a disturbing action of the adsorbent surface, water occurs in the quasi-liquid state. As a result, it is observed in the 1H NMR spectra as a relatively narrow signal. The signal of ice is not registered due to great differences in the transverse relaxation times of the adsorbed water and ice. The method of measuring the free surface energy of the adsorbents from the temperature dependence of the signal intensity of non-freezing water is based on the fact that the temperature of water freezing decreases by the quantity which depends on the surface energy and the distance of the adsorbed molecules from the solid surface. The water at the interface freezes when the free energies of the adsorbed water and ice are equal. To illustrate the applicability of the method under consideration the series of adsorption systems in which the absorbents used differed in the surface chemistry and porous structure. In particular, the behaviour of water on the surface of the following adsorbents is discussed: non-porous and porous silica (aerosils, silica gels); chemically and physically modified non-porous and porous silica (silanization, carbonization, biopolymer deposition); and pyrogeneous Al2O3 and aluminasilicas. The effect of preliminary treatment of the adsorbent (thermal, high pressure, wetting with polar and non-polar solvents) on the characteristics

  14. 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.

  15. The Impact of Enzyme Orientation and Electrode Topology on the Catalytic Activity of Adsorbed Redox Enzymes

    Science.gov (United States)

    McMillan, Duncan G. G.; Marritt, Sophie J.; Kemp, Gemma L.; Gordon-Brown, Piers; Butt, Julea N.; Jeuken, Lars J. C.

    2014-01-01

    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. PMID:24634538

  16. The Impact of Enzyme Orientation and Electrode Topology on the Catalytic Activity of Adsorbed Redox Enzymes.

    Science.gov (United States)

    McMillan, Duncan G G; Marritt, Sophie J; Kemp, Gemma L; Gordon-Brown, Piers; Butt, Julea N; Jeuken, Lars J C

    2013-11-01

    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.

  17. Understanding the lateral movement of particles adsorbed at a solid-liquid interface.

    Science.gov (United States)

    Savaji, Kunal; Li, Xue; Couzis, Alexander

    2015-09-01

    In this paper we study the phenomenon of lateral movement of particles that are electrostatically adsorbed at a solid-liquid interface. The experimental system involves negatively charged silica particles of two different sizes (65 nm and 90 nm) that are exposed to the positively charged solid surface (silane coated silicon wafer) in sequential steps. The particle-adsorbed wafers are analyzed under a scanning electron microscope and the images are processed to determine the pair-correlation function for the particles adsorbed in the first step. From the pair correlation data and the particle surface coverage data we show that the adsorbed particles are mobile at the solid-liquid interface. In specific, we show that the adsorbed particles are mobile at the solid-liquid interface when there is a driving force for the adsorbed particles to move. The driving force in the scheme of experiments discussed in this paper is the reduction in the free energy of the system.

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

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Taewoon; Lee, Seung-Kon; Lee, Suseung; Lee, Jun Sig [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2015-10-15

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

  19. EFFECT OF WEAK INTERACTIONS ON PHENOL ADSORPTION FROM AQUEOUS SOLUTIONS BY AMINATED POLYMERIC ADSORBENTS

    Institute of Scientific and Technical Information of China (English)

    Wei-ming Zhang; Jin-long Chen; Ai-min Li; Bing-cai Pan; Qun Chen; Ming-yang He; Quan-xing Zhang

    2006-01-01

    Adsorption behaviors of phenol from aqueous solutions have been investigated in batch systems at 303 K and 318 K respectively, using hypercrosslinked polymeric adsorbent (CHA 111), aminated hypercrosslinked polymeric adsorbents (NDA101, NDA 103, NDA105) and weakly basic polymeric adsorbent (D301) with a view to studying the effect of hydrogen bonding and Van der Waals interactions between adsorbate and the adsorbent. All adsorption isotherms can be well fitted by Langmuir and Freundlich equations. Compared with D301 driven by hydrogen bonding interaction only and CHA111 driven by Van der Waals interaction only, phenol adsorption on aminated adsorbents driven by both hydrogen bonding and Van der Waals interactions were apparently different, i.e., negative effect for NDA105, positive effect for NDA101 and synergistic effect for NDA103. In this synergistic action, some weak interactions would contribute more or less to the adsorption than they work individually.

  20. Selection and evaluation of adsorbents for the removal of anionic surfactants from laundry rinsing water.

    Science.gov (United States)

    Schouten, Natasja; van der Ham, Louis G J; Euverink, Gert-Jan W; de Haan, André B

    2007-10-01

    Low-cost adsorbents were tested to remove anionic surfactants from laundry rinsing water to allow re-use of water. Adsorbents were selected corresponding to the different surfactant adsorption mechanisms. Equilibrium adsorption studies of linear alkyl benzene sulfonate (LAS) show that ionic interaction results in a high maximum adsorption capacity on positively charged adsorbents of 0.6-1.7 gLAS/g. Non-ionic interactions, such as hydrophobic interactions of LAS with non-ionic resins or activated carbons, result in a lower adsorption capacity of 0.02-0.6 gLAS/g. Negatively charged materials, such as cation exchange resins or bentonite clay, have negligible adsorption capacities for LAS. Similar results are obtained for alpha olefin sulfonate (AOS). Cost comparison of different adsorbents shows that an inorganic anion exchange material (layered double hydroxide) and activated carbons are the most cost-effective materials in terms of the amount of surfactant adsorbed per dollar worth of adsorbent.

  1. A WATER—COMPATIBLE PHENOLIC HYDROXYL ODIFIED POLYSTYRENE AS AN ADSORBENT FOR ADSORBING PHENOLIC COMPOUNDS FROM AQUEOUS SOLUTIONS

    Institute of Scientific and Technical Information of China (English)

    LIAimin; FeiZhenghao; 等

    2001-01-01

    A water-compatible phenolic hydroxyl modified polystyrene adsorbent (AM-1) for adsorbing and removing phenolic compounds from aqueous solutions was prepared by covalent bonding of phenolic hydroxyl groups to the surface of porous polystyrene-divinylbenzene beads,this resin can be used directly without wetting process.A comparison of the sorption properites of the new resin and Amberlite XAD-4 toward four phenolic compounds,phenol,p-cresol,p-chlorophenol,and p-nitrophenol was made.The capacities of equilibrium adsorption of AM-1 for all four phenolic compounds increased around 20% over that of Amberlite XAD-4,which may be contributed to pheonl hydroxyl group on the surface and the unusual poe distribution.At their dilute solution,the equilibrium adsorption capacities of AM-1 for phenol increased aout 62% over that of Amberlite XAD-4,while equilibrium adsorption capacities of the other three phenolic compounds increased 4-35%,suggesting an advantage of AM-1 over Amberlite XAD-4 in the collection of phenol.Freundlich isotherm equations and isosteric adsorption enthalpies for the four phenolic compunds indicate a physical adsorption process on the Amberlite XAD-4 and AM-1 resins,Column studies for phenol show that AM-1 resin has excellent adsorption and desorption performance.

  2. The Effects of Organic Adsorbates on the Underpotential Deposition of Silver on Pt(111) Electrodes

    Science.gov (United States)

    1993-01-01

    CV) The Effects of Organic Adsorbates on the Underpotential Deposition W.0 of Silver on Pt(111) Electrodes _• D. L. Taylor and H. D. Abruxla* D TIC...to determine the effects of competing organic adsorbates on the underpotential deposition of silver on Pt(111). The adsorbates studied are known to...hcis )n appive tor pubic release and sal Its distribution is unlimited. fu .. 93-12456 INTRODUCTION The process of underpotential deposition (UPD) of

  3. Experimental and Numerical Investigation of Enhancement of Heat and Mass Transfer in Adsorbent Beds

    Institute of Scientific and Technical Information of China (English)

    LiuZhenyan; FuZhumantffu

    1994-01-01

    Some interrelated parameters of heat and mass transfer in two phases of pressure rise and constant pressure are obtained by studying the desorption processes of two kinds of cylindrical adsorbent beds.with fins and without fins.Moreover,the effects of equivalent thermal conductivity of adsorbent beds,contact thermal transfer coefficient,heat transfer of fins,condensation temperature,uncondensable gas in the adsorber are analyzed.finally,enhancement of heat and mass transfer has been attained.

  4. The origin and characterization of conformational heterogeneity in adsorbed polymer layers

    Science.gov (United States)

    Douglas, Jack F.; Schneider, Hildegard M.; Frantz, Peter; Lipman, Robert; Granick, Steve

    1997-09-01

    The equilibration of polymer conformations tends to be sluggish in polymer layers adsorbed onto highly attractive substrates, so the structure of these layers must be understood in terms of the layer growth process rather than equilibrium theory. Initially adsorbed chains adopt a highly flattened configuration while the chains which arrive later must adapt their configurations to the increasingly limited space available for adsorption. Thus, the chains adsorbed in the late stage of deposition are more tenuously attached to the surface. This type of non-equilibrium growth process is studied for polymethylmethacrylate (PMMA) adsorbed on oxidized silicon where the segmental attraction is strong (0953-8984/9/37/005/img7/segment) and for polystyrene (PS) adsorbed on oxidized silicon from a carbon tetrachloride solution where the segmental attraction is relatively weak (0953-8984/9/37/005/img8/segment). Measurements were based on Fourier transform infrared spectroscopy in attenuated total reflection (FTIR - ATR). In both cases, the chains arriving first adsorbed more tightly, became flattened (as measured by the dichroic ratio), and occupied a disproportionately large fraction of the surface. This non-uniform structure persisted indefinitely for the strongly adsorbed PMMA chains, while the PS chains exhibited a gradual evolution, presumably reflecting an equilibration of the adsorbed layer occurring after long times. On the theoretical side, the initial heterogeneity of these adsorbed polymer layers is modelled using a random sequential adsorption (RSA) model where the size of the adsorbing species is allowed to adapt to the surface space available at the time of adsorption. The inhomogeneity in the size of adsorbing species (hemispheres) in this model is similar to the distribution of chain contacts in our measurements on adsorbed polymer layers. Owing to extensive variance around the mean, conformations having the mean number of chain contacts are least probable, which

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

    Science.gov (United States)

    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.

  6. CONDUCTIVITY METHOD APPLIED TO THE STUDY OF INTERACTION BETWEEN ADSORBENT AND ADSORBATE I.ADSORPTION OF LOW CONCENYRATION OF FREE ACID BY REGENERABLE CHITIN

    Institute of Scientific and Technical Information of China (English)

    ChenBingren; HeGuangping; 等

    1997-01-01

    The adsorption of low concentration of free acid by regenerable chitin is followed by electric conductance determination.The effect of acid concentratioin,content of functioinal amino groups,and ionic strength on adsorption was discussed.Experimental results indicate that the active centre of regenerable chitin is the free amino groups on ist surface ,and that the rate of adsorption of free acid was found to be affected by two factors:the interaction between the adsorbent and the adsorbate in solution and that between the adsorbate molecules or ions in solution.

  7. Nicotinic acid as a new co-adsorbent in dye-sensitized solar cells

    DEFF Research Database (Denmark)

    Nguyen, Phuong Tuyet; Nguyen, Vinh Son; Van Le, Tan Nhuut;

    2017-01-01

    with that of DSCs fabricated with two well-established co-adsorbents i.e., chenodeoxycholic acid (CDA) and octadecylphosphonic acid (OPA). The findings showed that under optimized co-adsorbent concentration (1 mM NTA, 0.03 mM CDA, 0.015 mM OPA), the efficiency of the corresponding solar cells increased to the same......With the aim of introduction a new inexpensive co-adsorbent to improve solar cell performance, the influence of nicotinic acid (NTA) used as a co-adsorbent in dye-sensitized solar cells (DSCs) was investigated. The findings showed that low concentrations of NTA (

  8. SYNTHESIS OF SPHERICAL MACROPOROUS ADSORBENT BASED ON UREA—FORMALDEHYDE CONDENSED POLYMER

    Institute of Scientific and Technical Information of China (English)

    XUMingcheng; XUMancai; 等

    2000-01-01

    Spherical macroporous adsorbents with active sites capable of hydrogen bonding adsorption based on urea-formaldehyde condensed polymer were synthesized via reversed suspension polymerization.The properties of the obtained adsorbent were also investigated in detail.The results showed that the water permeability could be improved by adding hydroxyl-contatining organic compound moiety into the adsorbent.The specific surface area and average pore diameter of these adsorbents increaswed while the porosity first increased then decreased with the increase of the amount of the added hydroxyl-containing compound.

  9. Toward an effective adsorbent for polar pollutants: formaldehyde adsorption by activated carbon.

    Science.gov (United States)

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

    2013-09-15

    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.

  10. Dynamic characteristics of helium adsorbents. Influence of the heat removal conditions

    Science.gov (United States)

    Shcherbachenko, R. I.; Grigor'ev, V. N.

    2008-06-01

    The static and dynamic characteristics of the adsorbent SKN-1K at 4.2K are investigated under conditions corresponding to the working conditions of adsorption pumps in dilution refrigerators. It is shown that gluing this adsorbent to the cooled surface leads to a substantial lowering of the pressure in the pump in the dynamic regime. On the basis of experimental data for the glued and free adsorbent an estimate is made of the hydrodynamic contribution to the pressure due to the resistance of the pores of the adsorbent. This estimate falls within the error of measurement.

  11. Electronic properties of NH4-adsorbed graphene nanoribbon as a promising candidate for a gas sensor

    Science.gov (United States)

    Harada, Naoki; Sato, Shintaro

    2016-05-01

    The electronic properties of NH4-adsorbed N = 7 armchair graphene nanoribbons (AGNRs) were theoretically investigated using self-consistent atomistic simulations to explore the feasibility of AGNRs as a gas sensing material. Whereas a pristine AGNR has a finite band gap and is an intrinsic semiconductor, an NH4-adsorbed AGNR exhibits heavily doped n-type properties similar to a graphene sheet with the molecules adsorbed. The electric characteristics of a back-gated AGNR gas sensor were also simulated and the drain current changed exponentially with increasing number of adsorbed molecules. We may conclude that an AGNR is promising as a highly sensitive gas-sensing material with large outputs.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2015-06-01

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

  13. Adsorbed polyelectrolyte coatings decrease Fe(0) nanoparticle reactivity with TCE in water: conceptual model and mechanisms.

    Science.gov (United States)

    Phenrat, Tanapon; Liu, Yueqiang; Tilton, Robert D; Lowry, Gregory V

    2009-03-01

    The surfaces of reactive nanoscale zerovalent iron (NZVI) particles used for in situ groundwater remediation are modified with polymers or polyelectrolytes to enhance colloidal stability and mobility in the subsurface. However, surface modification decreases NZVI reactivity. Here, the TCE dechlorination rate and reaction products are measured as a function of adsorbed polyelectrolyte mass for three commercially available polyelectrolytes used for NZVI surface modification including poly(styrene sulfonate) (PSS), carboxymethyl cellulose (CMC), and polyaspartate (PAP). The adsorbed mass, extended layer thickness, and TCE-polyelectrolyte partition coefficient are measured and used to explain the effect of adsorbed polyelectrolyte on NZVI reactivity. For all modifiers, the dechlorination rate constant decreased nonlinearly with increasing surface excess, with a maximum of a 24-fold decrease in reactivity. The TCE dechlorination pathways were not affected. Consistent with Scheutjens-Fleer theory for homopolymer adsorption, the nonlinear relationship between the dechlorination rate and the surface excess of adsorbed polyelectrolyte suggests that adsorbed polyelectrolyte decreases reactivity primarily by blocking reactive surface sites at low surface excess where they adsorb relatively flat onto the NZVI surface, and by a combination of site blocking and decreasing the aqueous TCE concentration at the NZVI surface due to partitioning of TCE to adsorbed polyelectrolytes. This explanation is also consistent with the effect of adsorbed polyelectrolyte on acetylene formation. This conceptual model should apply to other medium and high molecular weight polymeric surface modifiers on nanoparticles, and potentially to adsorbed natural organic matter.

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

    Energy Technology Data Exchange (ETDEWEB)

    Thiruvenkatachari, Ramesh [Commonwealth Scientific and Industrial Research Organisation (CSIRO), PO Box 883, Kenmore, Queensland 4069 (Australia); Su Shi, E-mail: Shi.Su@csiro.au [Commonwealth Scientific and Industrial Research Organisation (CSIRO), PO Box 883, Kenmore, Queensland 4069 (Australia); Yu Xinxiang [Commonwealth Scientific and Industrial Research Organisation (CSIRO), PO Box 883, Kenmore, Queensland 4069 (Australia)

    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.

  15. 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.

  16. 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 α-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}.

  17. Compositional and micro-scratch analyses of laser induced colored surface of titanium

    Science.gov (United States)

    Akman, Erhan; Cerkezoglu, Ecem

    2016-09-01

    Laser marking of metallic surface is a very important application for industry. It is revealed that controlled oxide layer generation above the treated surface leads to colored appearance of metals with interference effect. The oxide layer control is provided with laser and process parameters. In this study, different colors of the Grade 2 titanium samples have been obtained by varying the laser scanning speed. Chromaticity coordinates of the different color surface have been calculated from the reflectance spectrum of the samples. Compositional analyses have been performed using X-ray photoelectron spectroscopy and X-ray diffraction methods. To examine the mechanical properties of the surface, micro-scratch test has been applied to all the colored surfaces. Although delamination has been observed between two laser scanning speed as 950 mm/s and 450 mm/s, it can be said that the adhesion between the titanium substrate and the oxide coating is good.

  18. Enhancing the reactivity of gold: Nanostructured Au(111) adsorbs CO

    Science.gov (United States)

    Hoffmann, F. M.; Hrbek, J.; Ma, S.; Park, J. B.; Rodriguez, J. A.; Stacchiola, D. J.; Senanayake, S. D.

    2016-08-01

    Low-coordinated sites are surface defects whose presence can transform a surface of inert or noble metal such as Au into an active catalyst. Starting with a well-ordered Au(111) surface we prepared by ion sputtering gold surfaces modified by pits, used microscopy (STM) for their structural characterization and CO spectroscopy (IRAS and NEXAFS) for probing reactivity of surface defects. In contrast to the Au(111) surface CO adsorbs readily on the pitted surfaces bonding to low-coordinated sites identified as step atoms forming {111} and {100} microfacets. Pitted nanostructured surfaces can serve as interesting and easily prepared models of catalytic surfaces with defined defects that offer an attractive alternative to vicinal surfaces or nanoparticles commonly employed in catalysis science.

  19. Liquid 4He Adsorbed Films on Very Attractive Substrates

    Science.gov (United States)

    Urrutia, Ignacio; Szybisz, Leszek

    Adsorbed films of liquid 4He are analized, in the framework of Density Functional Theories (DF). In these systems, when the substrate becomes increasingly attractive, the thin films of 4He approaches the quasi-bidimensional limit. We study this strongly attractive substrate regime with two DF, the Orsay-Trento (OT) and a recent Hybrid proposal (Hyb), focusing in the energy behavior. It is showed that OT does not reproduce the correct limiting energy curve, and it implies that this functional could not provide reliable results for very strongly attractive substrates like Graphite (Gr). In other hand, with the Hyb DF, the correct energy behavior is found for the adsorption energy of 4He on Gr. These results show that OT should not be applied to quasi 2D (confinement) situations, and that Hyb DF provides a much more realistic description.

  20. Liquid 4He Adsorbed Films on Very Attractive Substrates

    Science.gov (United States)

    Urrutia, Ignacio; Szybisz, Leszek

    2006-09-01

    Adsorbed films of liquid 4He are analized, in the framework of Density Functional Theories (DF). In these systems, when the substrate becomes increasingly attractive, the thin films of 4He approaches the quasi-bidimensional limit. We study this strongly attractive substrate regime with two DF, the Orsay-Trento (OT) and a recent Hybrid proposal (Hyb), focusing in the energy behavior. It is showed that OT does not reproduce the correct limiting energy curve, and it implies that this functional could not provide reliable results for very strongly attractive substrates like Graphite (Gr). In other hand, with the Hyb DF, the correct energy behavior is found for the adsorption energy of 4He on Gr. These results show that OT should not be applied to quasi 2D (confinement) situations, and that Hyb DF provides a much more realistic description.

  1. Sunflower stalks as adsorbents for color removal from textile wastewater

    Energy Technology Data Exchange (ETDEWEB)

    Sun, G.; Xu, X. [Univ. of California, Davis, CA (United States). Div. of Textiles and Clothing

    1997-03-01

    Sunflower stalks as adsorbents for two basic dyes (Methylene Blue and Basic Red 9) and two direct dyes (Congo Red and Direct Blue 71) in aqueous solutions were studied with equilibrium isotherms and kinetic adsorptions. The maximum adsorptions of two basic dyes on sunflower stalks are very high, i.e., 205 and 317 mg/g for Methylene Blue and Basic Red 9, respectively. The two direct dyes have relatively lower adsorption on sunflower stalks. The adsorptive behaviors of sunflower stalk components are different. The pith, which is the soft and porous material in the center of stalks, has twice the adsorptive capacity of the skin. Particle sizes of sunflower stalks also affect the adsorption of dyes. The adsorption rates of two basic dyestuffs are much higher than that of the direct dyes. Within 30 min about 80% basic dyes were removed from the solutions.

  2. CALCULATION OF THE YOUNG'S MODULUS OF AN ADSORBED POLYMER LAYER

    Institute of Scientific and Technical Information of China (English)

    Rüdiger Stark; Michael Kappl; Hans-Jürgen Butt

    2007-01-01

    Polymer layers adsorbed to a surface or in a confined environment often change their mechanical properties. There is even the possibility of solidification of the confined layer. To judge the stiffness of such a layer, we used the Hertz model to calculate the Young's modulus of the polymer layer in the confinement of AFM experiments with silicon nitride tip with a radius of curvature of R ≈ 50 nm and a glass sphere attached to the cantilever R = 5 μm. Since there is no visible indentation of the layer in the AFM experiments, the layer is either penetrated very easily, or the indentation is too small to be seen in a force curve. The latter would be the case for a polymer layer with a Young's modulus above 4×108 Pa in case of an experiment with a silicon nitride tip and 4×105 Pa in case of a glass sphere.

  3. Photoluminescence Enhancement of Adsorbed Species on Si Nanoparticles.

    Science.gov (United States)

    Matsumoto, Taketoshi; Maeda, Masanori; Kobayashi, Hikaru

    2016-12-01

    We have fabricated Si nanoparticles from Si swarf using the beads milling method. The mode diameter of produced Si nanoparticles was between 4.8 and 5.2 nm. Si nanoparticles in hexane show photoluminescence (PL) spectra with peaks at 2.56, 2.73, 2.91, and 3.09 eV. The peaked PL spectra are attributed to the vibronic structure of adsorbed dimethylanthracene (DMA) impurity in hexane. The PL intensity of hexane with DMA increases by ~3000 times by adsorption on Si nanoparticles. The PL enhancement results from an increase in absorption probability of incident light by DMA caused by adsorption on the surface of Si nanoparticles.

  4. Spontaneous Symmetry Breaking in Metal Adsorbed Graphene Sheets

    CERN Document Server

    Jalbout, A F

    2012-01-01

    Graphene has received a great deal of attention and this has more recently extended to boron nitride sheets (BNS) with a similar structure. Both have hexagonal lattices and it is only the alternation of atoms in boron nitride, which changes the symmetry structure. This difference can for example be seen in the mean field equations, which for the corners of the Brillouin Zone are Dirac equations. For the case of graphene (equal atoms) we have the equation for massless particles, while for Boron Nitride has a finite gap and is more near a Dirac equation with mass near this gap.. Carbon structures in general and in particular also graphene can adsorb electron donors, such as alkaline atoms or molecules with a dipole moment. Typically these atoms and the dipoles can only attach in the sense to donate electron density. Some results for small sheet like structures are available.

  5. Charge transfer properties of pentacene adsorbed on silver: DFT study

    Energy Technology Data Exchange (ETDEWEB)

    N, Rekha T.; Rajkumar, Beulah J. M., E-mail: beulah-rajkumar@yahoo.co.in [PG & Research Department of Physics, Lady Doak College, Madurai 625002 (India)

    2015-06-24

    Charge transfer properties of pentacene adsorbed on silver is investigated using DFT methods. Optimized geometry of pentacene after adsorption on silver indicates distortion in hexagonal structure of the ring close to the silver cluster and deviations in co-planarity of carbon atoms due to the variations in bond angles and dihedral angles. Theoretically simulated absorption spectrum has a symmetric surface plasmon resonance peak around 486nm corresponding to the transfer of charge from HOMO-2 to LUMO. Theoretical SERS confirms the process of adsorption, tilted orientation of pentacene on silver surface and the charge transfers reported. Localization of electron density arising from redistribution of electrostatic potential together with a reduced bandgap of pentacene after adsorption on silver suggests its utility in the design of electro active organic semiconducting devices.

  6. Dynamics of monolayers adsorbed at the solid-liquid interface

    Energy Technology Data Exchange (ETDEWEB)

    Clarke, Stuart M. [BP Institute, Department of Chemistry, Univ. of Cambridge (United Kingdom); Inaba, Akira [Department of Chemistry, Osaka Univ., Osaka (Japan); Arnold, Thomas [Physical and Theoretical Chemistry Laboratory, Univ. of Oxford (United Kingdom); Thomas, Robert K.; Castro, Miguel A. [Instituto de Ciencia de Materiale de Sevilla, Avda. Americo Vespucio (Spain)

    2001-03-01

    Recently we have demonstrated, using a variety of techniques including calorimetry and neutron diffraction, the existence of translationally ordered two-dimensional phases of short chain n-alkanes (CnH2n+2) on the surface of graphite. Dodecane (n=12) is unusual in that it is found from diffraction experiments to adopt a structure with parallel molecules, similar to that seen for the odd alkanes, and exhibits a monolayer phase transition at 281 K, before the layer melts at 286 K. This additional transition is reminiscent of the rotator phase transitions seen in the longer bulk alkanes. In this work we present elastic incoherent neutron scattering (EISF) data which probe the dynamics of the monolayer and clearly demonstrate that the adsorbed layer is indeed far from static but has a high degree of rotational mobility. (author)

  7. Evaluation of {sup 131}I retention in several adsorbers

    Energy Technology Data Exchange (ETDEWEB)

    Catanoso, Marcela F.; Osso Junior, Joao Alberto, E-mail: marcela.forli@gmail.co, E-mail: jaosso@ipen.b [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil). Diretoria de Radiofarmacia

    2011-07-01

    Several iodine radioisotopes are used in nuclear medicine for treatment and diagnostic purposes. The radioisotope {sup 131}I is used both in diagnosis and therapy due to its physical characteristics of decay by {beta}{sup -} and its {gamma}-ray emissions suitable for diagnosis. It is routinely produced at IPEN through the irradiation of TeO{sub 2} targets in the IEA-R1m nuclear reactor. After the irradiation, the {sup 131}I is separated by dry distillation, where the targets are put in an oven, heated at 760 deg C for 2 hours and the {sup 131}I, volatile, is carried by an O{sub 2} gas stream. The aim of this work was to evaluate the retention and elution of {sup 131}I samples produced at IPEN in several adsorbers as part of a project aiming the purification of these radioisotopes, allowing the labeling of biomolecules. Samples of {sup 131}I were used for retention and elution studies with the following adsorbers: commercial cartridges, anionic resin columns and cationic resin column. The results showed that Ag cartridges and anionic resins Dowex 1X8, Dowex 3 and IRA 400 had a great iodine retention but no elution after using specific eluents. The QMA light, acid alumina, neutral alumina and cationic resin Dowex 50WX4 showed high retention and elution and QMA plus and cationic resin Dowex 50WX8 and Dowex 50WX12 had a good retention but lower elution. Regarding to the better retention and elution, Ag cartridges and resins showed a higher percentage of iodine retention but lower elution yield and QMA light, acid and neutral alumina cartridges showed better results. (author)

  8. 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

  9. Amino-functionalized mesoporous MCM-41 silica as an efficient adsorbent for water treatment: batch and fixed-bed column adsorption of the nitrate anion

    Science.gov (United States)

    Ebrahimi-Gatkash, Mehdi; Younesi, Habibollah; Shahbazi, Afsaneh; Heidari, Ava

    2015-11-01

    In the present study, amino-functionalized Mobil Composite Material No. 41 (MCM-41) was used as an adsorbent to remove nitrate anions from aqueous solutions. Mono-, di- and tri-amino functioned silicas (N-MCM-41, NN-MCM-41 and NNN-MCM-41) were prepared by post-synthesis grafting method. The samples were characterized by means of X-ray powder diffraction, FTIR spectroscopy, thermogravimetric analysis, scanning electron microscopy and nitrogen adsorption-desorption. The effects of pH, initial concentration of anions, and adsorbent loading were examined in batch adsorption system. Results of adsorption experiments showed that the adsorption capacity increased with increasing adsorbent loading and initial anion concentration. It was found that the Langmuir mathematical model indicated better fit to the experimental data than the Freundlich. According to the constants of the Langmuir equation, the maximum adsorption capacity for nitrate anion by N-MCM-41, NN-MCM-41 and NNN-MCM-41 was found to be 31.68, 38.58 and 36.81 mg/g, respectively. The adsorption kinetics were investigated with pseudo-first-order and pseudo-second-order model. Adsorption followed the pseudo-second-order rate kinetics. The coefficients of determination for pseudo-second-order kinetic model are >0.99. For continuous adsorption experiments, NNN-MCM-41 adsorbent was used for the removal of nitrate anion from solutions. Breakthrough curves were investigated at different bed heights, flow rates and initial nitrate anion concentrations. The Thomas and Yan models were utilized to calculate the kinetic parameters and to predict the breakthrough curves of different bed height. Results from this study illustrated the potential utility of these adsorbents for nitrate removal from water solution.

  10. Selective cesium removal from radioactive liquid waste by crown ether immobilized new class conjugate adsorbent

    Energy Technology Data Exchange (ETDEWEB)

    Awual, Md. Rabiul, E-mail: awual.rabiul@jaea.go.jp [Actinide Coordination Chemistry Group, Quantum Beam Science Centre (QuBS), Japan Atomic Energy Agency (SPring-8), Hyogo 679-5148 (Japan); Yaita, Tsuyoshi [Actinide Coordination Chemistry Group, Quantum Beam Science Centre (QuBS), Japan Atomic Energy Agency (SPring-8), Hyogo 679-5148 (Japan); Taguchi, Tomitsugu [Nano-Structure Synthesis Research Group, Quantum Beam Science Centre (QuBS), Japan Atomic Energy Agency, Tokai-mura, Ibaraki-ken 319-1195 (Japan); Shiwaku, Hideaki; Suzuki, Shinichi; Okamoto, Yoshihiro [Actinide Coordination Chemistry Group, Quantum Beam Science Centre (QuBS), Japan Atomic Energy Agency (SPring-8), Hyogo 679-5148 (Japan)

    2014-08-15

    Graphical abstract: - Highlights: • DB24C8 crown ether was functionalized for preparation of conjugate adsorbent. • Radioactive {sup 137}Cs can be selectively removed by the conjugate adsorbent. • Adsorbent can effectively capture Cs even in the presence of a high amount Na and K. • Adsorbent is reversible and able to be reused without significant deterioration. - Abstract: Conjugate materials can provide chemical functionality, enabling an assembly of the ligand complexation ability to metal ions that are important for applications, such as separation and removal devices. In this study, we developed ligand immobilized conjugate adsorbent for selective cesium (Cs) removal from wastewater. The adsorbent was synthesized by direct immobilization of dibenzo-24-crown-8 ether onto inorganic mesoporous silica. The effective parameters such as solution pH, contact time, initial Cs concentration and ionic strength of Na and K ion concentrations were evaluated and optimized systematically. This adsorbent was exhibited the high surface area-to-volume ratios and uniformly shaped pores in case cavities, and its active sites kept open functionality to taking up Cs. The obtained results revealed that adsorbent had higher selectivity toward Cs even in the presence of a high concentration of Na and K and this is probably due to the Cs–π interaction of the benzene ring. The proposed adsorbent was successfully applied for radioactive Cs removal to be used as the potential candidate in Fukushima nuclear wastewater treatment. The adsorbed Cs was eluted with suitable eluent and simultaneously regenerated into the initial form for the next removal operation after rinsing with water. The adsorbent retained functionality despite several cycles during sorption-elution-regeneration operations.

  11. Investigations on the adsorbents for uremic middle molecular toxins (II) —Influences of crosslinking agent chain length on the adsorption capacities of crosslinked chitosan adsorbents

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    Chitosan resins, which clinically served as adsorbents in hemoperfusion therapy, were prepared with reversed-phase suspension methodology using three differently structured crosslinking agents, methanal, glyoxal and glutaraldehyde. And the glyoxal and glutaraldehyde crosslinked chitosan resins were reduced with NaBH4 afterwards. By analyzing the results from FTIR and SEM, it was found that the reduction treatment to the adsorbents efficiently improved the chemical stability of these chitosan resins, and the shifts in crosslinking agents exerted influences over the morphologies of the adsorbents obviously. After being put to use in the adsorption tests upon some model uremic middle molecular toxins and BSA in vitro, all three adsorbents demon- strated a fairly realistic adsorption capability to the model toxins but little to BSA. And the adsorp- tion process reached the equilibrium in a clinically qualified short time. But the adsorption capaci- ties of these adsorbents to the model toxins were quite different. It had been found that with the growing of fatty chain length of crosslinking agent, these adsorbents showed a gradually increased adsorption capacity to the model toxins, and the glutaraldehyde crosslinked chitosan resin be- haved best.

  12. Effect of adsorbed films on friction of Al2O3-metal systems

    Science.gov (United States)

    Pepper, S. V.

    1976-01-01

    The kinetic friction of polycrystalline Al2O3 sliding on Cu, Ni, and Fe in ultrahigh vacuum was studied as a function of the surface chemistry of the metal. Clean metal surfaces were exposed to O2, Cl2, C2H4, and C2H3Cl, and the change in friction due to the adsorbed species was observed. Auger electron spectroscopy assessed the elemental composition of the metal surface. It was found that the systems exposed to Cl2 exhibited low friction, interpreted as the van der Waals force between the Al2O3 and metal chloride. The generation of metal oxide by oxygen exposures resulted in an increase in friction, interpreted as due to strong interfacial bonds established by reaction of metal oxide with Al2O3 to form the complex oxide (spinel). The only effect of C2H4 was to increase the friction of the Fe system, but C2H3Cl exposures decreases friction in both Ni and Fe systems, indicating the dominance of the chlorine over the ethylene complex on the surface

  13. Carbon-Based Adsorbents for Postcombustion CO2 Capture: A Critical Review.

    Science.gov (United States)

    Creamer, Anne Elise; Gao, Bin

    2016-07-19

    The persistent increase in atmospheric CO2 from anthropogenic sources makes research directed toward carbon capture and storage imperative. Current liquid amine absorption technology has several drawbacks including hazardous byproducts and a high-energy requirement for regeneration; therefore, research is ongoing to develop more practical methods for capturing CO2 in postcombustion scenarios. The unique properties of carbon-based materials make them specifically promising for CO2 adsorption at low temperature and moderate to high partial pressure. This critical review aims to highlight the development of carbon-based solid sorbents for postcombustion CO2 capture. Specifically, it provides an overview of postcombustion CO2 capture processes with solid adsorbents and discusses a variety of carbon-based materials that could be used. This review focuses on low-cost pyrogenic carbon, activated carbon (AC), and metal-carbon composites for CO2 capture. Further, it touches upon the recent progress made to develop metal organic frameworks (MOFs) and carbon nanomaterials and their general CO2 sorption potential.

  14. Shotgun proteomic analytical approach for studying proteins adsorbed onto liposome surface

    KAUST Repository

    Capriotti, Anna Laura

    2011-07-02

    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. © 2011 Springer-Verlag.

  15. Adsorptive desulfurization of model oil using untreated, acid activated and magnetite nanoparticle loaded bentonite as adsorbent

    Directory of Open Access Journals (Sweden)

    Muhammad Ishaq

    2017-02-01

    Full Text Available The present research work focuses on a novel ultraclean desulfurization process of model oil by the adsorption method using untreated, acid activated and magnetite nanoparticle loaded bentonite as adsorbent. The parameters investigated are effect of contact time, adsorbent dose, initial dibenzothiophene (DBT concentration and temperature. Experimental tests were conducted in batch process. Pseudo first and second order kinetic equations were used to examine the experimental data. It was found that pseudo second order kinetic equation described the data of the DBT adsorption onto all types of adsorbents very well. The isotherm data were analyzed using Langmuir and Freundlich isotherm models. The Langmuir isotherm model fits the data very well for the adsorption of DBT onto all three forms of adsorbents. The adsorption of DBT was also investigated at different adsorbent doses and was found that the percentage adsorption of DBT was increased with increasing the adsorbent dose, while the adsorption in mg/g was decreased with increasing the adsorbent dose. The prepared adsorbents were analyzed by scanning electron microscopy (SEM, energy dispersive X-ray spectrometry (EDX and X-ray diffraction (XRD.

  16. Selection and evaluation of adsorbents for the removal of anionic surfactants from laundry rinsing water

    NARCIS (Netherlands)

    Schouten, Natasja; Ham, Louis G.J. van der; Euverink, Gert-Jan W.; Haan, André B. de

    2007-01-01

    Low-cost adsorbents were tested to remove anionic surfactants from laundry rinsing water to allow re-use of water. Adsorbents were selected corresponding to the different surfactant adsorption mechanisms. Equilibrium adsorption studies of linear alkyl benzene sulfonate (LAS) show that ionic interact

  17. Adsorbate-metal bond effect on empirical determination of surface plasmon penetration depth.

    Science.gov (United States)

    Kegel, Laurel L; Menegazzo, Nicola; Booksh, Karl S

    2013-05-21

    The penetration depth of surface plasmons is commonly determined empirically from the observed response for adsorbate loading on gold surface plasmon resonance (SPR) substrates. However, changes in the SPR spectrum may originate from both changes in the effective refractive index near the metal surface and changes in the metal permittivity following covalent binding of the adsorbate layer. Herein, the significance of incorporating an additional adsorbate-metal bonding effect in the calculation is demonstrated in theory and in practice. The bonding effect is determined from the nonzero intercept of a SPR shift versus adsorbate thickness calibration and incorporated into the calculation of penetration depth at various excitation wavelengths. Determinations of plasmon penetration depth with and without the bonding response for alkanethiolate-gold are compared and are shown to be significantly different for a thiol monolayer adsorbate system. Additionally, plasmon penetration depth evaluated with bonding effect compensation shows greater consistency over different adsorbate thicknesses and better agreement with theory derived from Maxwell's equation, particularly for adsorbate thicknesses that are much smaller (<5%) than the plasmon penetration depth. The method is also extended to a more practically applicable polyelectrolyte multilayer adsorbate system.

  18. Dye removal from wastewater using the adsorbent developed from sewage sludge

    Institute of Scientific and Technical Information of China (English)

    CHEN Chun-yun; WANG Peng; ZHUANG Yuan-yi

    2005-01-01

    Sewage sludge was used to develop an effective carbon adsorbent. This adsorbent was employed for the removal of azo dye such as Direct Dark Brown M and Acid Mordant Brown RH. The adsorption of dyes on this adsorbent was studied as a function of contact time, concentration, pH and temperature by batch method. The equilibrium adsorption capacity of a carbonaceous adsorbent prepared from city wastewater treatment plant was 502, and 329.7 mg/g of Direct Dark Brown M and Acid Mordant Brown RH, respectively. The experimental data were analyzed by the Langmuir and Freundlich models of adsorption. Equilibrium data fitted well with the Langmuir model. The rates of adsorption were found to conform to the Lagergren second-order kinetics with good correlation. The equilibrium adsorption capacity of the carbonaceous adsorbents was determined with the Langmuir equation as well as the Lagergren second-order rate equation. The most ideal pH for adsorption of two dyes onto adsorbents was found to be 3 and below. The results indicate that the carbonaceous adsorbents could be employed as a low cost adsorbent in the removal of dyes from wastewater.

  19. Structure and dynamics of egg white ovalbumin adsorbed at the air/water interface

    NARCIS (Netherlands)

    Kudryashova, E.V.; Meinders, M.B.J.; Visser, A.J.W.G.; Hoek, A. van; Jongh, H.H.J. de

    2003-01-01

    The molecular properties of egg white ovalbumin adsorbed at the air/water interface were studied using infrared reflection absorption spectroscopy (IRRAS) and time-resolved fluorescence anisotropy (TRFA) techniques. Ovalbumin adsorbed at the air/ water interface adopts a characteristic partially unf

  20. Primary, secondary, and tertiary amines for CO2 capture: designing for mesoporous CO2 adsorbents.

    Science.gov (United States)

    Ko, Young Gun; Shin, Seung Su; Choi, Ung Su

    2011-09-15

    CO(2) emissions, from fossil-fuel-burning power plants, the breathing, etc., influence the global worming on large scale and the man's work efficiency on small scale. The reversible capture of CO(2) is a prominent feature of CO(2) organic-inorganic hybrid adsorbent to sequester CO(2). Herein, (3-aminopropyl) trimethoxysilane (APTMS), [3-(methylamino)propyl] trimethoxysilane (MAPTMS), and [3-(diethylamino) propyl] trimethoxysilane (DEAPTMS) are immobilized on highly ordered mesoporous silicas (SBA-15) to catch CO(2) as primary, secondary, and tertiary aminosilica adsorbents. X-ray photoelectron spectroscopy was used to analyze the immobilized APTMS, MAPTMS, and DEAPTMS on the SBA-15. We report an interesting discovery that the CO(2) adsorption and desorption on the adsorbent depend on the amine type of the aminosilica adsorbent. The adsorbed CO(2) was easily desorbed from the adsorbent with the low energy consumption in the order of tertiary, secondary, and primary amino-adsorbents while the adsorption amount and the bonding-affinity increased in the reverse order. The effectiveness of amino-functionalized (1(o), 2(o), and 3(o) amines) SBA-15s as a CO(2) capturing agent was investigated in terms of adsorption capacity, adsorption-desorption kinetics, and thermodynamics. This work demonstrates apt amine types to catch CO(2) and regenerate the adsorbent, which may open new avenues to designing "CO(2) basket".