WorldWideScience

Sample records for adsorbents

  1. Transporting method for adsorbing tower and the adsorbing tower

    International Nuclear Information System (INIS)

    Shimokawa, Nobuhiro.

    1996-01-01

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

  2. The state of physically adsorbed substances in microporous adsorbents

    International Nuclear Information System (INIS)

    Fomkin, A.A.

    1987-01-01

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

  3. 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

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

    DEFF Research Database (Denmark)

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

    2010-01-01

    a large tolerance to monatomic surface steps on the Ag(110) surface. The observed behaviour is explained in terms of strong intermolecular hydrogen bonding and a strong surface-mediated directionality, assisted by a sufficient degree of molecular backbone flexibility. In contrast, the same kind of step......-edge crossing is not observed when the molecules are adsorbed on the isotropic Ag(111) or more reactive Cu(110) surfaces. On Ag(111), similar 1-D assemblies are formed to those on Ag(110), but they are oriented along the step edges. On Cu(110), the carboxylic groups of NDCA are deprotonated and form covalent...... bonds to the surface, a situation which is also achieved on Ag(110) by annealing to 200 degrees C. These results show that the formation of particular self-assembled molecular nanostructures depends significantly on a subtle balance between the adsorbate-adsorbate and adsorbate-substrate interactions...

  5. 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.

  6. Orientational epitaxy in adsorbed monolayers

    International Nuclear Information System (INIS)

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

    1977-01-01

    The ground state for adsorbed monolayers on crystalline substrates is shown to involve a definite relative orientation of the substrate and adsorbate crystal axes, even when the relative lattice parameters are incommensurate. The rotation angle which defines the structure of the monolayer-substrate system is determined by the competition between adsorbate-substrate and adsorbate-adsorbate energy terms, and is generally not a symmetry angle. Numerical predictions are presented for the rare gas-graphite systems, whose interaction potentials are rather well known. Recent LEED data for some of these systems appear to corroborate these predictions

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

    International Nuclear Information System (INIS)

    Koske, P.H.; Ohlrogge, K.

    1984-01-01

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

  8. Positronium chemistry in porous adsorbents

    International Nuclear Information System (INIS)

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

    1981-01-01

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

  9. Ecological applications of the irradiated adsorbents

    International Nuclear Information System (INIS)

    Tusseyev, T.

    2004-01-01

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

  10. Iodine removal adsorbent histories, aging and regeneration

    International Nuclear Information System (INIS)

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

    1976-01-01

    The experience of efficiency changes with life under various test conditions is described. The adsorbents were periodically removed from both standby and continuously operating systems and tested under various test methods for residual iodine adsorption efficiency. Adsorbent from several conventional ''sampler'' cartridges versus the bulk adsorbent was also tested showing deficiency in the use of cartridge type sampling. Currently required test conditions were found inadequate to follow the aging of the adsorbent because pre-equilibration of the sample acts as a regenerant and the sample is not tested in the ''as is'' condition. The most stringent test was found to be the ambient temperature, high humidity test to follow the aging of the adsorbent. Several methods were evaluated to regenerate used adsorbents; of these high temperature steaming and partial reimpregnation were found to produce adsorbents with near identical properties of freshly prepared adsorbents

  11. 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.

  12. 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.

  13. 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)

  14. 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.

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

    International Nuclear Information System (INIS)

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

    1986-01-01

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

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

    International Nuclear Information System (INIS)

    Lovric, D.; Gumhalter, B.

    1988-01-01

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

  17. Krypton retention on solid adsorbents

    International Nuclear Information System (INIS)

    Monson, P.R. Jr.

    1980-01-01

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

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

    Energy Technology Data Exchange (ETDEWEB)

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

    1967-07-01

    The geometry and the technology of a cell used for investigations on electron-adsorbed gas interactions are described. The resonance frequencies of the surface ions which are created by the electron impact on the adsorbed gas are predicted by simplified calculations. The experimental data relative to carbon monoxide and neon are in good agreement with these predictions. (authors) [French] Les caracteristiques geometriques et technologiques generales d'une cellule d'etude des interactions entre un faisceau d'electrons et un gaz adsorbe sont donnees. Un calcul simplifie permet de prevoir les frequences de resonance des ions de surface crees par l'impact des electrons sur le gaz adsorbe. Les donnees experimentales sur l'oxyde de carbone et le neon confirment les previsions du calcul. (auteurs)

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

    Science.gov (United States)

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

    2017-08-15

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

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

    International Nuclear Information System (INIS)

    Koske, P.H.; Ohlrogge, K.

    1984-01-01

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

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

    International Nuclear Information System (INIS)

    Motojima, K.; Kawamura, F.

    1984-01-01

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

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

    International Nuclear Information System (INIS)

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

    2015-01-01

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

  3. 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

  4. Volatile organic compounds adsorption using different types of adsorbent

    Directory of Open Access Journals (Sweden)

    Pimanmes Chanayotha

    2014-09-01

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

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

    KAUST Repository

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

    2009-01-01

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

  6. 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....

  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. Method for modifying trigger level for adsorber regeneration

    Science.gov (United States)

    Ruth, Michael J.; Cunningham, Michael J.

    2010-05-25

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

  9. 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.

  10. Novel Fiber-Based Adsorbent Technology; FINAL

    International Nuclear Information System (INIS)

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

    2001-01-01

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

  11. WGS-Adsorbent Reaction Studies at Laboratory Scale

    International Nuclear Information System (INIS)

    Marano, M.; Torreiro, Y.

    2014-01-01

    This document reports the most significant results obtained during the experimental work performed under task WGS adsorbent experimental studies within CAPHIGAS project (National Research Plan 2008-2011, ref: ENE2009-08002). The behavior of the binary adsorbent-catalyst system which will be used in the hybrid system is described in this document. Main results reported here were used during the design and development of the hybrid system adsorbent catalyst- membrane proposed in the CAPHIGAS project. The influence of main operating parameters and the optimized volume ratio adsorbent-catalyst are also presented in this report. (Author)

  12. Dissolved Air Flotation of arsenic adsorbent particles

    Directory of Open Access Journals (Sweden)

    Mario Enrique Santander Muñoz

    2015-01-01

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

  13. Krypton retention on solid adsorbents

    International Nuclear Information System (INIS)

    Monson, P.R. Jr.

    1982-01-01

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

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

    International Nuclear Information System (INIS)

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

    2003-01-01

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

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

    International Nuclear Information System (INIS)

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

    2009-01-01

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

  16. 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.

  17. Development of adsorbents for recovery of uranium from seawater

    International Nuclear Information System (INIS)

    Egawa, Hiroaki; Furusaki, Shintaro.

    1987-01-01

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

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

    International Nuclear Information System (INIS)

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

    1988-01-01

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

  19. Irradiation Degradation of Adsorbents for Minor Actinides Recovery

    International Nuclear Information System (INIS)

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

    2015-01-01

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

  20. Investigations Into the Reusability of Amidoxime-Based Polymeric Uranium Adsorbents

    Energy Technology Data Exchange (ETDEWEB)

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

    2016-09-28

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

  1. Processing method and device for iodine adsorbing material

    International Nuclear Information System (INIS)

    Watanabe, Shin-ichi; Shiga, Reiko.

    1997-01-01

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

  2. 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.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2013-02-15

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

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

    International Nuclear Information System (INIS)

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

    2013-01-01

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

  5. 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.

  6. Nano-sized Adsorbate Structure Formation in Anisotropic Multilayer System

    Science.gov (United States)

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

    2017-05-01

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

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

    Science.gov (United States)

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

    2005-09-08

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

  8. 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.

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

    Science.gov (United States)

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

    2018-03-01

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

  10. Removal of adsorbent particles od copper ions by Jet flotation

    International Nuclear Information System (INIS)

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

    2009-01-01

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

  11. Properties and selection criteria for adsorbents

    International Nuclear Information System (INIS)

    Wirth, H.

    1976-01-01

    The paper gives a survey of the most important industrial adsorbents and of their suitability for different purposes. With special consideration of activated carbon, the properties and characteristic data are discussed which are used for assessing adsorbents. These, among other things, are as follows: specific surface area, pore size distribution, adsorption isotherms, hydrophobic properties, catalytic properties, chemical resistance, heat resistance, particle size and hardness. (orig.) [de

  12. Mixed-matrix membrane adsorbers for protein separation

    NARCIS (Netherlands)

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

    2003-01-01

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

  13. Thermodynamics of gas adsorption on solid adsorbents

    International Nuclear Information System (INIS)

    Budrugeac, P.

    1979-01-01

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

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

    KAUST Repository

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

    2016-01-01

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

  15. Photoemission spectroscopy of surfaces and adsorbates

    International Nuclear Information System (INIS)

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

    1982-01-01

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

  16. Selectivity of β-Sitosterol Imprinted Polymers as Adsorbent

    Science.gov (United States)

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

    2018-03-01

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

  17. 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

  18. Krypton retention on solid adsorbents

    International Nuclear Information System (INIS)

    Monson, P.R. Jr.

    1981-08-01

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

  19. Browns Ferry charcoal adsorber incident

    International Nuclear Information System (INIS)

    Mays, G.T.

    1979-01-01

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

  20. Adsorption of β-galactosidase on silica and aluminosilicate adsorbents

    Science.gov (United States)

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

    2015-03-01

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

  1. Production of Flocculants, Adsorbents, and Dispersants from Lignin.

    Science.gov (United States)

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

    2018-04-10

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

  2. Protein purification using magnetic adsorbent particles

    DEFF Research Database (Denmark)

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

    2006-01-01

    The application of functionalised magnetic adsorbent particles in combination with magnetic separation techniques has received considerable attention in recent years. The magnetically responsive nature of such adsorbent particles permits their selective manipulation and separation in the presence...... separations are fast, gentle, scaleable, easily automated, can achieve separations that would be impossible or impractical to achieve by other techniques, and have demonstrated credibility in a wide range of disciplines, including minerals processing, wastewater treatment, molecular biology, cell sorting...

  3. A nuclear standard high-efficiency adsorber for iodine

    International Nuclear Information System (INIS)

    Wang Jianmin; Qian Yinge

    1988-08-01

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

  4. Noble gas separation with the use of inorganic adsorbents

    International Nuclear Information System (INIS)

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

    1979-01-01

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

  5. Neutralization of Rubidium Adsorbate Electric Fields by Electron Attachment

    Energy Technology Data Exchange (ETDEWEB)

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

    2015-10-01

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

  6. Characterization of novel adsorbents for radiostrontium reduction in foods

    International Nuclear Information System (INIS)

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

    1999-01-01

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

  7. Methyl iodide tests on used adsorbents

    International Nuclear Information System (INIS)

    Kovach, J.L.

    1993-01-01

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

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

    Science.gov (United States)

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

    2006-05-01

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

  9. Production of Flocculants, Adsorbents, and Dispersants from Lignin

    Directory of Open Access Journals (Sweden)

    Jiachuan Chen

    2018-04-01

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

  10. Black molecular adsorber coatings for spaceflight applications

    Science.gov (United States)

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

    2014-09-01

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

  11. 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

  12. Synthesis and properties of porous zeolite aluminosilicate adsorbents

    International Nuclear Information System (INIS)

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

    2015-01-01

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

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

    International Nuclear Information System (INIS)

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

    1996-08-01

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

  14. Creation of the technical adsorbent from local raw materials

    International Nuclear Information System (INIS)

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

    2016-01-01

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

  15. Removal of VOCs from air stream with corrugated sheet as adsorbent

    Directory of Open Access Journals (Sweden)

    Rabia Arshad

    2016-10-01

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

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2006-05-15

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

  17. 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...

  18. Ionogenic adsorbents based on local raw materials for radiation protection

    International Nuclear Information System (INIS)

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

    2012-01-01

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

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

    KAUST Repository

    Li, Ang

    2016-01-01

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

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

    International Nuclear Information System (INIS)

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

    2013-01-01

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

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

    Energy Technology Data Exchange (ETDEWEB)

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

    1996-08-01

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

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

    Science.gov (United States)

    Lata, Sneh; Samadder, S R

    2016-01-15

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

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

    International Nuclear Information System (INIS)

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

    2011-01-01

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

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

    Directory of Open Access Journals (Sweden)

    Guangyan Tian

    2018-01-01

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

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2016-08-05

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

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

    International Nuclear Information System (INIS)

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

    2016-01-01

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

  7. Equilibrium and heat of adsorption of diethyl phthalate on heterogeneous adsorbents

    Energy Technology Data Exchange (ETDEWEB)

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

    2008-09-15

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

  8. Lotus Dust Mitigation Coating and Molecular Adsorber Coating

    Science.gov (United States)

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

    2015-01-01

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

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

    Science.gov (United States)

    Ćiçek, Ekrem; Dede, Bülent

    2013-12-01

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

  10. Black Sprayable Molecular Adsorber Coating

    Data.gov (United States)

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

  11. 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.

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

    International Nuclear Information System (INIS)

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

    1979-01-01

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

  13. Adsorption of uranium on adsorbents produced from used tires

    International Nuclear Information System (INIS)

    Mahramanlioglu, M.

    2003-01-01

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

  14. Heat transfer between adsorbate and laser-heated hot electrons

    International Nuclear Information System (INIS)

    Ueba, H; Persson, B N J

    2008-01-01

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

  15. Preparation of metal adsorbents from chitin/chitosan by radiation technology

    International Nuclear Information System (INIS)

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

    2004-01-01

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

  16. 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.

  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

  18. Enhanced vanillin production from ferulic acid using adsorbent resin.

    Science.gov (United States)

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

    2007-03-01

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

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

    International Nuclear Information System (INIS)

    Usenko, A S

    2014-01-01

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

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

    Directory of Open Access Journals (Sweden)

    Haider M. Zwain

    2014-01-01

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

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

    International Nuclear Information System (INIS)

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

    2010-01-01

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

  2. PERVAPORATION USING ADSORBENT-FILLED MEMBRANES

    Science.gov (United States)

    Membranes containing selective fillers, such as zeolites and activated carbon, can improve the separation by pervaporation. Applications of adsorbent-filled membranes in pervaporation have been demonstrated by a number of studies. These applications include removal of organic co...

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

    African Journals Online (AJOL)

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

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

    Science.gov (United States)

    Gupta, V K; Suhas

    2009-06-01

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

  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. Preparation and characterization of a novel adsorbent from Moringa oleifera leaf

    Science.gov (United States)

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

    2017-06-01

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

  7. SAPO-34 coated adsorbent heat exchanger for adsorption chillers

    International Nuclear Information System (INIS)

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

    2015-01-01

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

  8. 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...

  9. Electronic properties of adsorbates and clean surfaces of metals and semiconductors

    International Nuclear Information System (INIS)

    Lecante, J.

    1980-01-01

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

  10. Biological adsorbent for water decontamination from uranium

    Energy Technology Data Exchange (ETDEWEB)

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

    1978-01-01

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

  11. Biological adsorbent for water decontamination from uranium

    International Nuclear Information System (INIS)

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

    1978-01-01

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

  12. Characterisation of lignite as an industrial adsorbent

    Energy Technology Data Exchange (ETDEWEB)

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

    2011-04-15

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

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

    International Nuclear Information System (INIS)

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

    2015-01-01

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

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

    Science.gov (United States)

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

    2015-12-21

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

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

    International Nuclear Information System (INIS)

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

    2015-01-01

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

  16. The Dynamics and Structures of Adsorbed Surfaces

    DEFF Research Database (Denmark)

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

    1978-01-01

    . Elastic neutron diffraction measurements, determining the two-dimensional structural ordering of the adsorbed films, have been performed on layers of N2, Ar, H2, D2, O2, Kr, and He. Measurements on layers of larger molecules such as CD4 and ND3 have also been reported. Inelastic neutron scattering...... measurements, studying the dynamics of the adsorbed films are only possible in a few especially favourable cases such as 36Ar and D2 films, where the coherent phonon scattering cross-sections are very large. In other cases incoherent scattering from hydrogen can give information about e.g. the mobility...

  17. Adsorbents for radioactive organic solvent wastes

    International Nuclear Information System (INIS)

    Ichinose, Shigeo; Kiribayashi, Takehiko.

    1986-01-01

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

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

    Directory of Open Access Journals (Sweden)

    Nasim Habibi

    2017-08-01

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

  19. Scanning tunneling spectroscopy of Co adsorbates on superconducting Pb nanostructures

    Energy Technology Data Exchange (ETDEWEB)

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

    2015-07-01

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

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

    International Nuclear Information System (INIS)

    Koenst, J.W. Jr.

    1977-01-01

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

  1. Black Sprayable Molecular Adsorber Coating Project

    Data.gov (United States)

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

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

    Energy Technology Data Exchange (ETDEWEB)

    Boki, K

    1974-10-25

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

  3. Retention of radium from thermal waters on sand filters and adsorbents

    Energy Technology Data Exchange (ETDEWEB)

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

    2007-06-18

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

  4. Retention of radium from thermal waters on sand filters and adsorbents

    International Nuclear Information System (INIS)

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

    2007-01-01

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

  5. 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.

  6. 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.

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

    Science.gov (United States)

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

    2015-06-02

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

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

    International Nuclear Information System (INIS)

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

    2002-01-01

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

  9. 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.

  10. Green Adsorbents for Wastewaters: A Critical Review

    Science.gov (United States)

    Kyzas, George Z.; Kostoglou, Margaritis

    2014-01-01

    One of the most serious environmental problems is the existence of hazardous and toxic pollutants in industrial wastewaters. The major hindrance is the simultaneous existence of many/different types of pollutants as (i) dyes; (ii) heavy metals; (iii) phenols; (iv) pesticides and (v) pharmaceuticals. Adsorption is considered to be one of the most promising techniques for wastewater treatment over the last decades. The economic crisis of the 2000s led researchers to turn their interest in adsorbent materials with lower cost. In this review article, a new term will be introduced, which is called “green adsorption”. Under this term, it is meant the low-cost materials originated from: (i) agricultural sources and by-products (fruits, vegetables, foods); (ii) agricultural residues and wastes; (iii) low-cost sources from which most complex adsorbents will be produced (i.e., activated carbons after pyrolysis of agricultural sources). These “green adsorbents” are expected to be inferior (regarding their adsorption capacity) to the super-adsorbents of previous literature (complex materials as modified chitosans, activated carbons, structurally-complex inorganic composite materials etc.), but their cost-potential makes them competitive. This review is a critical approach to green adsorption, discussing many different (maybe in some occasions doubtful) topics such as: (i) adsorption capacity; (ii) kinetic modeling (given the ultimate target to scale up the batch experimental data to fixed-bed column calculations for designing/optimizing commercial processes) and (iii) critical techno-economical data of green adsorption processes in order to scale-up experiments (from lab to industry) with economic analysis and perspectives of the use of green adsorbents. PMID:28788460

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

    Science.gov (United States)

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

    2011-07-01

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

  12. Cost analysis of seawater uranium recovered by a polymeric adsorbent system

    International Nuclear Information System (INIS)

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

    2014-01-01

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

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

    DEFF Research Database (Denmark)

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

    1998-01-01

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

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

    Science.gov (United States)

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

    2013-01-01

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

  15. 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.

  16. Adsorption behavior of lithium from seawater using manganese oxide adsorbent

    International Nuclear Information System (INIS)

    Wajima, Takaaki; Munakata, Kenzo; Uda, Tatsuhiko

    2012-01-01

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

  17. Kinetics of conformational changes of fibronectin adsorbed onto model surfaces.

    Science.gov (United States)

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

    2008-05-01

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

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

    Directory of Open Access Journals (Sweden)

    Alexander Sperlich

    2017-06-01

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

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

    International Nuclear Information System (INIS)

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

    1982-01-01

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

  20. Simulations of the Static Friction Due to Adsorbed Molecules

    OpenAIRE

    He, Gang; Robbins, Mark O.

    2001-01-01

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

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

    DEFF Research Database (Denmark)

    Vives, E.; Lindgård, P.-A.

    1993-01-01

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

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

    Energy Technology Data Exchange (ETDEWEB)

    1971-05-01

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

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2017-09-29

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

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

    Science.gov (United States)

    Steiner, M; Boller, M

    2006-01-01

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

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

    Science.gov (United States)

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

    2003-08-01

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

  6. Solid adsorbents for removal of hydrogen sulphide from hot gas

    Energy Technology Data Exchange (ETDEWEB)

    Furimsky, E.; Yumura, Motoo

    1986-04-01

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

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

    International Nuclear Information System (INIS)

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

    2014-01-01

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

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

    Science.gov (United States)

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

    2017-10-01

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

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

    CSIR Research Space (South Africa)

    Debnath, S

    2015-01-01

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

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

    KAUST Repository

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

    2009-01-01

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

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

    International Nuclear Information System (INIS)

    Okamoto, Jiro; Sugo, Takanobu

    1990-01-01

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

  12. Specific binding-adsorbent assay method and test means

    International Nuclear Information System (INIS)

    1981-01-01

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

  13. Production of adsorbent from palm shell for radioactive iodine scrubbing process

    International Nuclear Information System (INIS)

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

    2010-01-01

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

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

    International Nuclear Information System (INIS)

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

    2010-01-01

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

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

    International Nuclear Information System (INIS)

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

    2010-01-01

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

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

    Science.gov (United States)

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

    2018-03-01

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

  17. 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.

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

    Directory of Open Access Journals (Sweden)

    Mazhar I. Khaskheli

    2014-06-01

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

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2012-09-15

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

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

    Science.gov (United States)

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

    2017-02-01

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

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

    International Nuclear Information System (INIS)

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

    2009-01-01

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

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

    International Nuclear Information System (INIS)

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

    2004-01-01

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

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

    Science.gov (United States)

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

    2015-03-01

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

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

    Directory of Open Access Journals (Sweden)

    Saad Hanash Ammar

    2015-12-01

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

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

    International Nuclear Information System (INIS)

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

    1989-01-01

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

  6. Stochastic Description of Activated Surface Diffusion with Interacting Adsorbates

    Science.gov (United States)

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

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

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

    International Nuclear Information System (INIS)

    Matsukawa, Hiroshi; Haraguchi, Kazuhiro; Ozaki, Shinsuke

    2007-01-01

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

  8. Quantitative relationship between adsorbed amount of solute and solvent composition

    International Nuclear Information System (INIS)

    Wang Yan; Geng Xindu; Zebolsky, Don M.

    2003-01-01

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

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2007-07-01

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

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

    Science.gov (United States)

    Eshraghi, Farahnaz; Nezamzadeh-Ejhieh, Alireza

    2018-03-08

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

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

    International Nuclear Information System (INIS)

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

    1978-01-01

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

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

    International Nuclear Information System (INIS)

    Moattar, F.; Hayeripour, S.

    2004-01-01

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

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

    Science.gov (United States)

    Maruyama, Masashi; Shibuya, Keisuke

    2017-08-22

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

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

    International Nuclear Information System (INIS)

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

    2008-08-01

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

  15. Infrared Analysis Of Enzymes Adsorbed Onto Model Surfaces

    Science.gov (United States)

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

    1989-12-01

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

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

    Science.gov (United States)

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

    2017-12-01

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

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

    Directory of Open Access Journals (Sweden)

    Renin Chang

    2017-01-01

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

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2016-05-15

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

  19. Adsorbates in a Box: Titration of Substrate Electronic States

    Science.gov (United States)

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

    2010-08-01

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

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

    International Nuclear Information System (INIS)

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

    1984-01-01

    The desorption of uranium from the granular titanium-activated carbon composite adsorbent (concentration of uranium: 25.5 mg/1-Ad), which adsorbed uranium from natural sea water, was examined by the column process with acidic eluent at room temperature. The column operation was able to be carried out without destruction of the granular adsorbent by the generation of the carbon dioxide, and free from disturbance of the eluent flow by precipitate of calcium sulfate dihydrate with sulfuric acid eluent. The amount of acid consumption by the adsorbent was 0.87 eq/1-Ad. The alkaline earth metals were eluted in the range of elution volume below 2 1/1-Ad, whereas uranium, iron, and titanium were eluted above 2 1/1-Ad. Therefore, uranium was separable from the alkaline earth metals which were adsorbed in the most quantity in the adsorbent. In the range of elution volume 2 to 12 1/1-Ad, the percentage of desorbed uranium and the concentration ratio of uranium were 80 %, 680 with 0.5 N sulfuric acid, and 59 %, 490 with 0.5 N hydrochloric acid, respectively. The percentage of dissolved titanium (DTI) was 0.3 % with 0.5 N sulfuric acid, 0.26 % with 0.5 N hydrochloric acid in the same range. (author)

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2014-04-15

    We optimized the preparation method of pellet-type adsorbents based on alum sludge with the aim of developing a high-performance material for the adsorption of gaseous trimethylamine. Effects of calcination temperature on physical and chemical properties of pellet-type adsorbents were investigated. The porous structure and surface characteristics of the adsorbents were studied using N{sub 2} adsorption and desorption isotherms, scanning electron microscope, X-ray diffraction, temperature-programmed desorption of ammonia, and infrared spectroscopy of adsorbed pyridine. The adsorbents obtained from the water treatment sludge are microporous materials with well-developed mesoporosity. The pellet-type adsorbent calcined at 500 .deg. C had the highest percentage of micropore volume and the smallest average pore diameter. The highest adsorption capacity in trimethylamine removal attained over the pellet-type adsorbent calcined at 500 .deg. C can be attributed to the highest number of acid sites as well as the well-developed microporosity.

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

    Energy Technology Data Exchange (ETDEWEB)

    Shvoeva, O P; Kuchava, G P; Evtikova, G A; Belyaeva, V K; Myasoedova, G V; Marov, I N [AN SSSR, Moscow (USSR). Inst. Geokhimii i Analiticheskoj Khimii

    1989-04-01

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

  3. Adsorption behavior of cation-exchange resin-mixed polyethersulfone-based fibrous adsorbents with bovine serum albumin

    NARCIS (Netherlands)

    Zhang, Y.; Zhang, Yuzhong; Borneman, Zandrie; Koops, G.H.; Wessling, Matthias

    2006-01-01

    The cation-exchange resin-mixed polyethersulfone (PES)-based fibrous adsorbents were developed to study their adsorption behavior with bovine serum albumin (BSA). A fibrous adsorbent with an open pore surface had much better adsorption behavior with a higher adsorbing rate. The adsorption capacity

  4. Sulfur removal from fuel using zeolites/polyimide mixed matrix membrane adsorbents

    International Nuclear Information System (INIS)

    Lin, Ligang; Wang, Andong; Dong, Meimei; Zhang, Yuzhong; He, Benqiao; Li, Hong

    2012-01-01

    Graphical abstract: Membrane adsorption process is proposed for sulfur removal. Three-dimensional network structure is key to fulfill adsorption function of MMMs, which adsorption/desorption behavior is markedly related with binding force with sulfur molecules. Highlights: ► Membrane adsorption process is proposed for sulfur removal. ► Three-dimensional network structure of MMMs is key to fulfill adsorption function. ► Adsorption/desorption behavior is markedly related with binding force. - Abstract: A novel membrane adsorption process was proposed for the sulfur removal from fuels. The mixed matrix membranes (MMMs) adsorbents composed of polyimide (PI) and various Y zeolites were prepared. By the detailed characterization of FT-IR, morphology, thermal and mechanical properties of MMMs adsorbents, combining the adsorption and desorption behavior research, the process–structure–function relationship was discussed. Field-emission scanning electron microscope (FESEM) images show that the functional particles are incorporated into the three-dimensional network structure. MMMs adsorbents with 40% of zeolites content possess better physical properties, which was confirmed by mechanical strength and thermo stability analysis. Influence factors including post-treatment, content of incorporated zeolites, adsorption time, temperature, initial sulfur concentration as well as sulfur species on the adsorption performance of MMMs adsorbents have been evaluated. At 4 wt.% zeolites content, adsorption capacity for NaY/PI, AgY/PI and CeY/PI MMMs adsorbents come to 2.0, 7.5 and 7.9 mg S/g, respectively. And the regeneration results suggest that the corresponding spent membranes can recover about 98%, 90% and 70% of the desulfurization capacity, respectively. The distinct adsorption and desorption behavior of MMMs adsorbents with various functional zeolites was markedly related with their various binding force and binding mode with sulfur compounds.

  5. Development of adsorbent for C-14 Gas trapping and characteristics evaluation

    International Nuclear Information System (INIS)

    Park, Geun Il; Kim, I. T.; Kim, K. W.

    2006-08-01

    Desorption characteristics of C-14 adsorbed on spent resin as H 14 CO 3 ion type by applying various stripping solutions were analyzed, and some experiments for gasification of C-14 to CO 2 gas with were also performed. Based on these results, the process concept for spent resin treatment was suggested. Real spent resin was prepared from sampling in storage tank in site 1 of Wolseung Nuclear Power Plant. Desorption characteristics of C-14 and cations of Cs, Co from spent IRN-150 resin was evaluated. Desorption efficiency of C-14 from spent resin by using H 3 PO 4 desorption solution was over 96% regardless of C-14 amount on initial spent resin when comparing a activity of C-14 on initial spent resin. Also, desorption percent of cation of Cs, Co from anion ion-exchange resin (IRN-77) showed that Co-60 was below 1%, Cs-134, 137 was in a range of 2 ∼ 5%. Fundamental studies include an development of adsorbent manufacturing technology and its performance evaluation for C-14 gas trapping, the adsorption process by adopting gas circulation method was suggested for the design of 14 CO 2 gas treatment system generated from spent resin treatment process. In order to predict adsorbent performance of CO 2 trapping, modelling was carried out to verify the breakthrough curves of CO 2 trapping by using soda lime adsorbent. The effect of humidity on CO 2 trapping by using soda lime adsorbent was modelled via chemical reaction in porous media. Assessment of the state-of-the-arts on the solidification of the used adsorbent showed that the cement matrix would be the best-available binder from the view points of the matrix compatibility, properties of the final waste form, simplicity of the process and relatively low cost

  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. Bicarbonate Elution of Uranium from Amidoxime-Based Polymer Adsorbents for Sequestering Uranium from Seawater

    Energy Technology Data Exchange (ETDEWEB)

    Pan, Horng-Bin [Department of Chemistry, University of Idaho, Moscow, Idaho 83844 USA; Wai, Chien M. [Department of Chemistry, University of Idaho, Moscow, Idaho 83844 USA; Kuo, Li-Jung [Pacific Northwest National Laboratory, Marine Sciences Laboratory, Sequim, Washington 98382 USA; Gill, Gary [Pacific Northwest National Laboratory, Marine Sciences Laboratory, Sequim, Washington 98382 USA; Tian, Guoxin [Lawrence Berkeley National Laboratory, Berkeley, California 94720 USA; Rao, Linfeng [Lawrence Berkeley National Laboratory, Berkeley, California 94720 USA; Das, Sadananda [Materials Science and Technology Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831 USA; Mayes, Richard T. [Materials Science and Technology Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831 USA; Janke, Christopher J. [Materials Science and Technology Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831 USA

    2017-05-02

    Uranium adsorbed on amidoxime-based polyethylene fibers in simulated seawater can be quantitatively eluted using 3 M KHCO3 at 40°C. Thermodynamic calculations are in agreement with the experimental observation that at high bicarbonate concentrations (3 M) uranyl ions bound to amidoxime molecules are converted to uranyl tris-carbonato complex in the aqueous solution. The elution process is basically the reverse reaction of the uranium adsorption process which occurs at a very low bicarbonate concentration (~10-3 M) in seawater. In real seawater experiments, the bicarbonate elution is followed by a NaOH treatment to remove natural organic matter adsorbed on the polymer adsorbent. Using the sequential bicarbonate and NaOH elution, the adsorbent is reusable after rinsing with deionized water and the recycled adsorbent shows no loss of uranium loading capacity based on real seawater experiments.

  8. Supercritical fluid regeneration of adsorbents

    Science.gov (United States)

    Defilippi, R. P.; Robey, R. J.

    1983-05-01

    The results of a program to perform studies supercritical (fluid) carbon dioxide (SCF CO2) regeneration of adsorbents, using samples of industrial wastewaters from manufacturing pesticides and synthetic solution, and to estimate the economics of the specific wastewater treatment regenerations, based on test data are given. Processing costs for regenerating granular activated carbon GAC) for treating industrial wastewaters depend on stream properties and regeneration throughput.

  9. Radiation-induced reactions of amino acids adsorbed on solid surfaces

    Energy Technology Data Exchange (ETDEWEB)

    Lopez-Esquivel Kranksith, L.; Negron-Mendoza, A. [Instituto de Ciencias Nucleares, Universidad Nacional Autonoma de Mexico, UNAM. Cd. Universitaria, A.P. 70-543, 04510 Mexico D.F. (Mexico); Mosqueira, F.G. [Direcion General de Divulgacion de la Ciencia, Universidad Nacional Autonoma de Mexico, Cd. Universitaria, AP. 70-487 Mexico D.F. (Mexico); Ramos-Bernal, Sergio, E-mail: ramos@nucleares.unam.m [Instituto de Ciencias Nucleares, Universidad Nacional Autonoma de Mexico, UNAM. Cd. Universitaria, A.P. 70-543, 04510 Mexico D.F. (Mexico)

    2010-07-21

    The purpose of this work is to study the adsorption of compounds such as amino acids on clays and carbon nanotubes (CNTs) as a possible phase in the chemical evolution that may have occurred on the primitive Earth or in extraterrestrial environments. We further study the behavior of amino acids adsorbed on these solid surfaces at different conditions of pH and levels of irradiation, simulating a high-radiation field at early Earth conditions. The relevance of this work is to explain the possible contribution of solids (clays and CNTs) as promoters of polymerization and as shields for the adsorbed organic compounds against external sources of energy. To this end, tryptophan, aspartic acid, and glutamic acid were adsorbed on fixed amounts of solid surfaces and were irradiated by a {sup 60}Co source for different periods of time at fixed dose rates. After irradiation, the amino acids were extracted from the solid and analyzed with UV and IR spectroscopes and high-performance liquid chromatography. The most efficient surface for adsorption of amino acids was clay, followed by CNTs. Studies of the gamma irradiation of amino acids adsorbed on clay (in the solid phase) show a low yield of recovery of the amino acid.

  10. Nicotinic acid as a new co-adsorbent in dye-sensitized solar cells

    DEFF Research Database (Denmark)

    Nguyen, Phuong Tuyet; Nguyen, Vinh Son; Pham Phan, Thu Anh

    2017-01-01

    With the aim of introduction a new inexpensive co-adsorbent to improve solar cell performance, the influence of nicotinic acid (NTA) used as a co-adsorbent in dye-sensitized solar cells (DSCs) was investigated. The findings showed that low concentrations of NTA (

  11. A Method for Field Calibration of the PA260 Phosphorus Analyzer Using Solid Adsorbent Materials

    Science.gov (United States)

    1989-12-01

    plant environment. The solid adsorbent approach has two major advantages over other traditional air sampling devices such as bubblers or impingers...GC (60/80 mesh) or Chromosorb 106 (80/100 mesh). Both adsorbents were supplied by Alltech Associates (Deerfield, IL). The adsorbents were packed in

  12. Surface-enhanced Raman Spectroscopy of Ethephone Adsorbed on Silver Surface

    International Nuclear Information System (INIS)

    Lee, Chul Jae; Kim, Hee Jin; Karim, Mohammad Rezaul; Lee, Mu Sang

    2006-01-01

    We investigated the Surface-enhanced Raman Spectroscopy (SERS) spectrum of ethephone (2- chloroethylphosphonic acid). We observed significant signals in the ordinary Raman spectrum for solid-state ethephone as well as when it was adsorbed on a colloidal silver surface, strong vibrational signals were obtained at a very low concentration. The SERS spectra were obtained by silver colloids that were prepared by the γ - irradiation method. The influence of pH and the influence of anion (Cl - , Br - , I - ) on the adsorption orientation were investigated. Two different adsorption mechanisms were deduced, depending on the experimental conditions. The chlorine atom or the chlorine and two oxygen atoms were adsorbed on the colloidal silver surface. Among halide ions, Br - and I - were more strongly adsorbed on the colloidal silver surfaces. As a result, the adsorption of ethephone was less effective due to their steric hinderance

  13. Alkali metal adsorbate sputtering by molecular impact

    International Nuclear Information System (INIS)

    Moran, J.P.; Wachman, H.Y.; Trilling, L.

    1974-01-01

    An exploratory study of the sputtering by a krypton molecular beam of rubidium adsorbed at low coverage on a tungsten substrate has been described in a previous paper. An extension of this work is reported now

  14. 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.

  15. Oxidation of adsorbed ferrous iron: kinetics and influence of process conditions.

    Science.gov (United States)

    Buamah, R; Petrusevski, B; Schippers, J C

    2009-01-01

    For the removal of iron from groundwater, aeration followed with rapid (sand) filtration is frequently applied. Iron removal in this process is achieved through oxidation of Fe(2 + ) in aqueous solution followed by floc formation as well as adsorption of Fe(2 + ) onto the filter media. The rate of oxidation of the adsorbed Fe(2 + ) on the filter media plays an important role in this removal process. This study focuses on investigating the effect of pH on the rate of oxidation of adsorbed Fe(2 + ). Fe(2 + ) has been adsorbed, under anoxic conditions, on iron oxide coated sand (IOCS) in a short filter column and subsequently oxidized by feeding the column with aerated water. Ferrous ions adsorbed at pH 5, 6, 7 and 8 demonstrated consumption of oxygen, when aerated water was fed into the column. The oxygen uptake at pH 7 and 8 was faster than at pH 5 and 6. However the difference was less pronounced than expected. The difference is attributed to the pH buffering effect of the IOCS. At feedwater pH 5, 6 and 7 the pH in the effluent was higher than in the influent, while a pH drop should occur because of oxidation of adsorbed Fe(2 + ). At pH 8, the pH dropped. These phenomena are attributed to the presence of calcium and /or ferrous carbonate in IOCS.

  16. Synthesis of magnetic ordered mesoporous carbon (Fe-OMC) adsorbent and its evaluation for fuel desulfurization

    Science.gov (United States)

    Farzin Nejad, N.; Shams, E.; Amini, M. K.

    2015-09-01

    In this work, magnetic ordered mesoporous carbon adsorbent was synthesized using soft templating method to adsorb sulfur from model oil (dibenzothiophene in n-hexane). Through this research, pluronic F-127, resorcinol-formaldehyde and hydrated iron nitrate were respectively used as soft template, carbon source and iron source. The adsorbent was characterized by X-ray diffraction, nitrogen adsorption-desorption isotherm and transmission electron microscopy. Nitrogen adsorption-desorption measurement revealed the high surface area (810 m2 g-1), maxima pore size of 3.3 nm and large pore volume (1.01 cm3 g-1) of the synthesized sample. The adsorbent showed a maximum adsorption capacity of 111 mg dibenzothiophene g-1 of adsorbent. Sorption process was described by the pseudo-second-order rate equation and could be better fitted by the Freundlich model, showing the heterogeneous feature of the adsorption process. In addition, the adsorption capacity of regenerated adsorbent was 78.6% of the initial level, after five regeneration cycles.

  17. Investigation on removal of malachite green using EM based compost as adsorbent.

    Science.gov (United States)

    Bhagavathi Pushpa, T; Vijayaraghavan, J; Sardhar Basha, S J; Sekaran, V; Vijayaraghavan, K; Jegan, J

    2015-08-01

    The discarded materials from different sources can be utilized as effective materials in wastewater remediation. This proposed study was aimed mainly to investigate the possibility of Effective Microorganisms based compost (EMKC), which is derived from the kitchen solid waste, as a non-conventional low cost adsorbent for the removal of malachite green from aqueous solution. Batch experiments were carried out to evaluate the optimum operating parameters like pH (2-9), initial dye concentration (50-1000mg/L), adsorbent particle size (0.6-2.36mm) and adsorbent dosage (2-12g/L). EMKC recorded maximum uptake of 136.6mg/g of MG at pH 8, initial dye concentration 1000mg/L, adsorbent particle size 1.18mm and adsorbent dosage 4g/L. Two and three parameter adsorption models were employed to describe experimental biosorption isotherm data. The results revealed that the Sips model resulted in better fit than other models. The pseudo-first and -second order models were applied to describe kinetic data, of which the pseudo-second order described experimental data better with high correlation coefficient. This investigation suggested that EMKC could be an effective and low cost material for the removal of malachite green dye from aqueous solution. Copyright © 2015 Elsevier Inc. All rights reserved.

  18. Heat capacity of xenon adsorbed in nanobundle grooves

    International Nuclear Information System (INIS)

    Chishko, K.A.; Sokolova, E.S.

    2016-01-01

    A model of one-dimensional real gas under external transverse force field is applied to interpret the experimentally observed thermodynamical properties of xenon deposited into groves on the surface of carbon nanobundles. This non-ideal gas model with pair interaction is not quite adequate to describe the dense adsorbates (especially at low temperature limit), but it makes possible to take into account easily the particle exchange between 1D adsorbate and 3D atmosphere which becomes an essential factor since intermediate (for xenon - of order 35 K) up to high (approx 100 K) temperatures. In this paper we treat the 1D real gas with only Lennard-Jones pair interaction, but at presence of exact equilibrium conditions on the atom numbers between low-dimensional adsorbate and three-dimensional atmosphere of the experimental cell. The low-temperature branch of the heat capacity has been fitted separately within the elastic atomic chain model to get the best agreement between theory and experiment in as wide as possible region just from zero temperature. The gas approximation is introduced from the temperatures where the chain heat capacity tends definitely to 1D equipartition law. In this case the principal parameters for both models can be chosen in such a way that the heat capacity C(T) of the chain goes continuously into the corresponding curve of the gas approximation. So, it seems to be expected that adequate interpretation for temperature dependences of the atomic adsorbate heat capacity can be obtained through a reasonable combination of 1D gas and phonon approaches. The principal parameters of the gas approximation (such a desorption energy) found from the fitting between theory and experiment for xenon heat capacity are in good agreement with corresponding data known in literature.

  19. Treatment of Refinery Waste Water Using Environmental Friendly Adsorbent

    Science.gov (United States)

    Devi, M. Geetha; Al-Moshrafi, Samira Mohammed Khamis; Al Hudaifi, Alaa; Al Aisari, Buthaina Hamood

    2017-12-01

    This research evaluates the effectiveness of activated carbon prepared from walnut shell in the removal of pollutants from refinery waste water by adsorption technique. A series of batch experiments were carried out by varying the effluent solution pH, stirring time, stirring speed and adsorbent dosage in the reduction of pollutants from refinery effluent. Characterization of the adsorbent was performed using Scanning Electron Microscopy (SEM), Brunauer Emmett and Teller (BET) isotherm and Fourier Transform Infrared (FTIR) Spectroscopy. The best quality activated carbon was obtained with a particle size of 0.75 µm, activation temperature of 800 °C and activation time 24 h. The maximum BET surface area obtained was 165.2653 m2/g. The experimental results demonstrates that the highest percentage reduction in COD was 79%, using 0.6 g walnut shell powder at an optimum stirring speed of 100 rpm, at pH 6 and 120 min of contact time. The outcome of the result shows that walnut shell carbon is a potentially useful adsorbent for the removal of pollutants from refinery waste water.

  20. Thermal properties of polyfurfuryl alcohol absorbed/adsorbed on arylated soy protein films

    CSIR Research Space (South Africa)

    Kumar, R

    2012-02-01

    Full Text Available In this study, polyfurfuryl alcohol was absorbed/adsorbed on soy protein isolate films by immersing the SPI films in acid-catalysed furfuryl alcohol solution for 60 h followed by complete curing at 145–150 -C for 2 h. PFA absorbed/adsorbed soy...

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

    Energy Technology Data Exchange (ETDEWEB)

    Wei, Wei [Department of Environmental Science and Engineering, Nanjing Normal University, Nanjing 210023 (China); Jiangsu Provincial Key Laboratory of Materials Cycling and Pollution Control, Nanjing Normal University, Nanjing 210023 (China); Jiangsu Center for Collaborative Innovation in Geographical Information Resource Development and Application, Nanjing Normal University, Nanjing 210023 (China); Yang, Lei; Zhong, Wenhui; Cui, Jing [Department of Environmental Science and Engineering, Nanjing Normal University, Nanjing 210023 (China); Wei, Zhenggui, E-mail: weizhenggui@gmail.com [Department of Environmental Science and Engineering, Nanjing Normal University, Nanjing 210023 (China); Jiangsu Provincial Key Laboratory of Materials Cycling and Pollution Control, Nanjing Normal University, Nanjing 210023 (China); Jiangsu Center for Collaborative Innovation in Geographical Information Resource Development and Application, Nanjing Normal University, Nanjing 210023 (China)

    2015-03-30

    Graphical abstract: - Highlights: • Poorly crystalline HAP was firstly used for FA removal from aqueous solution. • The maximum adsorption capacity was determined to be 90.20 mg/g at 318 K. • Adsorption kinetics, isotherms and thermodynamic have been studied in detail. • Adsorption mechanism involved surface complexation, electrostatic interaction and hydrogen bonding. - Abstract: In this study, poorly crystalline hydroxyapatite (HAP) was developed as an efficient adsorbent for the removal of fulvic acid (FA) from aqueous solution. Surface functionality, crystallinity, and morphology of the synthetic adsorbent were studied by Fourier-transformation infrared (FT-IR) spectroscopy, powder X-ray diffraction (XRD) and transmission electron microscopy (TEM). The effects of various parameters such as crystallinity of adsorbent, contact time, adsorbent dosage, pH, initial adsorbate concentration, temperature, ionic strength and the presence of alkaline earth metal ions on FA adsorption were investigated. Results indicated that the nanosized HAP calcined at lower temperature was poorly crystalline (X{sub c} = 0.23) and had better adsorption capacity for FA than those (X{sub c} = 0.52, 0.86) calcined at higher temperature. FA removal was increased with increases of adsorbent dosage, temperature, ionic strength and the presence of alkali earth metal ions, but decreased as the pH increased. Kinetic studies showed that pseudo-second-order kinetic model better described the adsorption process. Equilibrium data were best described by Sips models, and the estimated maximum adsorption capacity of poorly crystalline HAP was 90.20 mg/g at 318 K, displaying higher efficiency for FA removal than previously reported adsorbents. FT-IR results revealed that FA adsorption over the adsorbent could be attributed to the surface complexation between the oxygen atom of functional groups of FA and calcium ions of HAP. Regeneration studies indicated that HAP could be recyclable for a long

  2. Heating and cooling system for an on-board gas adsorbent storage vessel

    Science.gov (United States)

    Tamburello, David A.; Anton, Donald L.; Hardy, Bruce J.; Corgnale, Claudio

    2017-06-20

    In one aspect, a system for controlling the temperature within a gas adsorbent storage vessel of a vehicle may include an air conditioning system forming a continuous flow loop of heat exchange fluid that is cycled between a heated flow and a cooled flow. The system may also include at least one fluid by-pass line extending at least partially within the gas adsorbent storage vessel. The fluid by-pass line(s) may be configured to receive a by-pass flow including at least a portion of the heated flow or the cooled flow of the heat exchange fluid at one or more input locations and expel the by-pass flow back into the continuous flow loop at one or more output locations, wherein the by-pass flow is directed through the gas adsorbent storage vessel via the by-pass line(s) so as to adjust an internal temperature within the gas adsorbent storage vessel.

  3. 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.

  4. Structures of adsorbed CO on atomically smooth and on stepped sngle crystal surfaces

    International Nuclear Information System (INIS)

    Madey, T.E.; Houston, J.E.

    1980-01-01

    The structures of molecular CO adsorbed on atomically smooth surfaces and on surfaces containing monatomic steps have been studied using the electron stimulated desorption ion angular distribution (ESDIAD) method. For CO adsorbed on the close packed Ru(001) and W(110) surfaces, the dominant bonding mode is via the carbon atom, with the CO molecular axis perpendicular to the plane of the surface. For CO on atomicaly rough Pd(210), and for CO adsorbed at step sites on four different surfaces vicinal to W(110), the axis of the molecule is tilted or inclined away from the normal to the surface. The ESDIAD method, in which ion desorption angles are related to surface bond angles, provides a direct determination of the structures of adsorbed molecules and molecular complexes on surfaces

  5. MODIFICATION OF KELUD VOLCANIC ASH 2014 AS SELECTIVE ADSORBENT MATERIAL FOR COPPER(II METAL ION

    Directory of Open Access Journals (Sweden)

    Susila Kristianingrum

    2017-01-01

      This research aims to prepare an adsorbent from Kelud volcanic ash for better Cu(II adsorption efficiency than Kiesel gel 60G E'Merck. Adsorbent synthesis was done by dissolving 6 grams of volcanic ash activated 700oC 4 hours and washed with HCl 0.1 M into 200 ml of 3M sodium hydroxide with stirring and heating of 100 °C for 1 hour. The filtrate sodium silicate was then neutralized using sulfuric acid. The mixture was allowed to stand for 24 hours then filtered and washed with aquaDM, then dried and crushed. The procedure is repeated for nitric acid, acetic acid and formic acid with a contact time of 24 hours. The products were then characterized using FTIR and XRD, subsequently determined acidity, moisture content, and tested for its adsorption of the ion Cu (II with AAS. The results showed that the type of acid that produced highest rendemen is AK-H2SO4-3M ie 36.93%, acidity of the adsorbent silica gel synthesized similar to Kiesel gel 60G E'Merck ie adsorbent AK-CH3COOH-3M and the water content of the silica gel adsorbent synthesized similar to Kiesel gel 60G E'Merck ie adsorbent AK-H2SO4-2 M. The character of the functional groups of silica gel synthesized all have similarities with Kiesel gel 60G E'Merck as a comparison. Qualitative analysis by XRD for all modified adsorbent showed a dominant peak of SiO2 except adsorbent AK-H2SO4 amorphous and chemical bonds with FTIR indicates that it has formed a bond of Si-O-Si and Si-OH. The optimum adsorption efficiency of the metal ions Cu(II obtained from AK-H2SO4-5M adsorbent that is equal to 93.2617% and the optimum adsorption capacity of the Cu(II metal ions was obtained from the adsorbent AK-CH3COOH-3M is equal to 2.4919 mg/ g.   Keywords: adsorbents, silica gel, adsorption, kelud volcanic ash

  6. 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

  7. Properties and behaviour of SO{sub 2} adsorbents for CFBC

    Energy Technology Data Exchange (ETDEWEB)

    Smith, I.M.

    2007-11-15

    Sulphur capture in FBC boilers usually relies on addition of limestone, which is not used efficiently. Limestones with lower sulphation capacities are undesirable because they increase the raw materials and the residues requiring management. This increases operating costs and CO{sub 2} emissions. It is preferable to use less limestone or shells instead. The performance of adsorbents varies widely and depends mainly on their morphology and microstructure rather than on their chemical properties. Adsorption mechanisms are investigated. Fragmentation and attrition are important during calcination. Sulphation is affected by boiler size, configuration, operating conditions, oxidising and reducing zones, reactions with compounds in coal ash, and attrition. Preparation and handling of limestone at the plant is examined and care has to be taken to avoid moisture in all systems. Recently designed plants achieve an SO{sub 2} capture efficiency at or over 95% with addition of adsorbent at a Ca:S molar ratio of 2-2.5 depending on the sulphur content of the fuel and the reactivity of the adsorbent. Various methods of enhancing SO{sub 2} capture are reviewed. Sorbent reactivation by pressurised steam hydration or grinding/hydration appear to be most promising but are not yet used on full-scale CFBC. Fuels and operating conditions affect emissions control and the production of residues. The adsorbent requirement may be reduced by cofiring with low sulphur high calcium fuels and by optimising the furnace temperature for different fuels. The effect of sulphur capture on other emissions ie examined. NOx and N{sub 2}O emissions may be reduced by choice of fuels and adsorbent. An increase in CO{sub 2} emissions results from minimising use of limestone or by carbonization/calcination to capture CO{sub 2} before sulphation. 110 refs., 11 figs., 10 tab.

  8. 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.

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

    International Nuclear Information System (INIS)

    Zhu, Xiangdong.

    1989-08-01

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

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

    International Nuclear Information System (INIS)

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

    2016-01-01

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

  11. Infrared spectroscopic and voltammetric study of adsorbed CO on stepped surfaces of copper monocrystalline electrodes

    International Nuclear Information System (INIS)

    Koga, O.; Teruya, S.; Matsuda, K.; Minami, M.; Hoshi, N.; Hori, Y.

    2005-01-01

    Voltammetric and infrared (IR) spectroscopic measurements were carried out to study adsorbed CO on two series of copper single crystal electrodes n(111)-(111) and n(111)-(100) in 0.1M KH 2 PO 4 +0.1M K 2 HPO 4 at 0 o C. Reversible voltammetric waves were observed below -0.55V versus SHE for adsorption of CO which displaces preadsorbed phosphate anions. The electric charge of the redox waves is proportional to the step atom density for both single crystal series. This fact indicates that phosphate anions are specifically adsorbed on the step sites below -0.55V versus SHE. Voltammetric measurements indicated that (111) terrace of Cu is covered with adsorbed CO below -0.5V versus SHE. Nevertheless, no IR absorption band of adsorbed CO is detected from (111) terrace. Presence of adsorbed CO on (111) terrace is presumed which is not visible by the potential difference spectroscopy used in the present work. IR spectroscopic measurements showed that CO is reversibly adsorbed with an on-top manner on copper single crystal electrodes of n(111)-(111) and n(111)-(100) with approximately same wavenumber of C?O stretching vibration of 2070cm -1 . The IR band intensity is proportional to the step atom density. Thus CO is adsorbed on (111) or (100) steps on the single crystal surfaces. An analysis of the IR band intensity suggested that one CO molecule is adsorbed on every two or more Cu step atom of the monocrystalline surface. The spectroscopic data were compared with those reported for uhv system. The C-O stretching wavenumber of adsorbed CO in the electrode-electrolyte system is 30-40cm -1 lower than those in uhv system

  12. Transport of significant metals recovered in real sea experiment of adsorbents

    International Nuclear Information System (INIS)

    Takeda, Hayato; Tamada, Masao; Kasai, Noboru; Katakai, Akio; Hasegawa, Shin; Seko, Noriaki; Sugo, Takanobu; Kawabata, Yukiya

    2001-10-01

    Real sea experiment for the recovery of significant metals such as uranium and vanadium which dissolved in seawater with extremely low concentration has been carried out at the offing of Mutsu establishment to evaluate the adsorption performance of adsorbent synthesized by radiation-induced graft-polymerization. The significant metals of uranium and vanadium eluted from the adsorbent which was soaked in the real sea were adsorbed onto the conventional chelate resin. The chelate resin which adsorbed the metals was packed in a plastic (PVC) column and further put in a cylindrical stainless transport container. This container was transported to the facility for separation and purification by a truck for the exclusive loading. Then the recovers metals were purified there. The recovered metals contained the uranium of 150g (1.92 MBq) and less in one recovery experiment. The maximum concentration is 60 Bq/g when the uranium is adsorbed on the chelate resin. Transport of recovered metals can be treated as general substance since these amount and concentration are out of legal control. However, the recovered metals were transported in conformity to L type Transport as a voluntary regulation. Though there is no requirements of structural strength for L type package legally, the structural strength of container was designed on that of IP-2 type which is higher transport grade than L type to take its safety measure. Its strength analysis proved the safety under general transport process. The transport was based on the plan made in advance. (author)

  13. Desorption of uranium from titanium-activated carbon composite adsorbent with acidic eluent, 1

    International Nuclear Information System (INIS)

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

    1984-01-01

    An investigation was carried out on the desorption of uranium from titanium-activated carbon composite adsorbent with acidic eluent by the batch process. The rate of desorption of uranium with acidic eluent depended on temperature, showing an increase as the temperature was raised. But the rate of desorption with acidic eluent was less dependent on temperature than that obtained when mixed eluent of sodium carbonate-sodium hydrogencarbonate was used. The rate of desorption of uranium did not vary in the range of concentration from 0.3 to 0.5 N, and the rate of desorption with sulfuric acid was slightly higher than that obtained when hydrochloric acid was used. The amount of dissolved titanium decreased as the ratio of adsorbent to eluent (RAE) was increased. At RAE of 10 %, the percentage of dissolved titanium (DTI) was below 0.38 % with sulfuric acid, below 0.7 % with hydrochloric acid. These values were found to be higher than the ones with the carbonate eluent. The elements except uranium, which were adsorbed on the adsorbent, were eluted simultaneously with acidic eluent. The regeneration of the adsorbent after desorption, therefore, was found to be unnecessary. In a repeated test of adsorption-desorption treatment up to five times, the percentage of uranium adsorbed from natural sea water was approximately constant of 85 %. From these results, the application of column process to the desorption of uranium with acidic eluent at room temperature was proposed to be feasible. (author)

  14. Desorption of uranium from titanium-activated carbon composite adsorbent with acidic eluent, (1)

    International Nuclear Information System (INIS)

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

    1983-01-01

    An investigation was carried out on the desorption of uranium from titanium-activated carbon composite adsorbent with acidic eluent by the batch process. The rate of desorption of uranium with acidic eluent depended on temperature, showing an increase as the temperature was raised. But the rate of desorption with acidic eluent was less dependent on temperature than that obtained when mixed eluent of sodium carbonate-sodium hydrogencarbonate was used. The difference of the rate of desorption of uranium in the range of concentration from 0.3 to 0.5N was not found, and the rate of desorption with sulfuric acid was slightly higher than that obtained when hydrochloric acid was used. The amount of dissolved titanium decreased as the ratio of adsorbent to eluent (RAE) was increased. At RAE of 10%, the percentage of dissolved titanium (DTI) was below 0.38% with sulfuric acid, below 0.7% with hydrochloric acid. These values were found to be higher than the ones with the carbonate eluent. The elements except uranium, which were adsorbed on the adsorbent, were eluted simultaneously with acidic eluent. The regeneration of the adsorbent after desorption, therefore, was found to be unnecessary. In a repeated test of adsorption-desorption treatment up to five times, the percentage of uranium adsorbed from natural sea water was approximately constant of 85%. From these results, the application of column process to the desorption of uranium with acidic eluent at room temperature was proposed to be feasible. (author)

  15. Application of nanoporous silicas as adsorbents for chlorinated aromatic compounds. A comparative study

    Energy Technology Data Exchange (ETDEWEB)

    Moritz, Michał, E-mail: michal.moritz@put.poznan.pl [Poznan University of Technology, Faculty of Chemical Technology, Institute of Chemistry and Technical Electrochemistry, Piotrowo 3, 60-965 Poznań (Poland); Adam Mickiewicz University, Faculty of Chemistry, Umultowska 89b, 61-614 Poznań (Poland); Geszke-Moritz, Małgorzata, E-mail: Malgorzata.Geszke-Moritz@amu.edu.pl [NanoBioMedical Centre, Adam Mickiewicz University, Umultowska 85, 61-614 Poznań (Poland)

    2014-08-01

    The removal of two selected environmental pollutants such as 2,4-dichlorophenoxyacetic acid (2,4-D) and Triclosan (TC) was examined by adsorption experiments on the modified SBA-15 and MCF mesoporous silicas. Mesoporous adsorbents were modified by a grafting process with (3-aminopropyl)triethoxysilane (APTES) and 1-[3-(trimethoxysilyl)propyl]urea (TMSPU). Mesoporous materials were synthesized and characterized by N{sub 2} adsorption–desorption experiment, transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FT-IR), elemental analysis and adsorption studies. The results show that both APTES-functionalized SBA-15 and MCF nanoporous carriers are potentially good adsorbents for the removal of 2,4-D in a wide range of concentrations from 0.1 to 4 mg/cm{sup 3}. Maximum adsorption capacity of as-modified adsorbents for 2,4-D estimated from the Langmuir model was ∼ 280 mg/g. The ionic interaction between the adsorbent and 2,4-D seems to play a key role in the adsorption process of the pollutant on APTES-modified siliceous matrices. The efficiency of TC sorption onto all prepared mesoporous adsorbents was significantly lower as compared to the entrapment of 2,4-D. Experimental data were best fitted by the Langmuir isotherm model. The results of this study suggest that mesoporous silica-based materials are promising adsorbents for the removal of selected organic pollutants. - Graphical abstract: Adsorption of 2,4-dichlorophenoxyacetic acid and Triclosan inside 3-amino-functionalized mesoporous channel.

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

    Digital Repository Service at National Institute of Oceanography (India)

    Sarma; Raju, G.R.K.

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

  17. Role of adsorbates on current fluctuations in DC field emission

    International Nuclear Information System (INIS)

    Luong, M.; Bonin, B.; Long, H.; Safa, H.

    1996-01-01

    Field emission experiments in DC regime usually show important current fluctuations for a fixed electric field. These fluctuations are attributed to adsorbed layers (molecules or atoms), liable to affect the work function, height and shape of the potential barrier binding the electron in the metal. The role of these adsorbed species is investigated by showing that the field emission from a well desorbed sample is stable and reproducible and by comparing the emission from the same sample before and after desorption. (author)

  18. Catalytic isotope exchange reaction between deuterium gas and water pre-adsorbed on platinum/alumina

    International Nuclear Information System (INIS)

    Iida, Itsuo; Kato, Junko; Tamaru, Kenzi.

    1976-01-01

    The catalytic isotope exchange reaction between deuterium gas and the water pre-adsorbed on Pt/Al 2 O 3 was studied. At reaction temperatures above 273 K, the exchange rate was proportional to the deuterium pressure and independent of the amount of adsorbed water, which suggests that the rate determining step is the supply of deuterium from the gas phase. Its apparent activation energy was 38 kJ mol -1 . Below freezing point of water, the kinetic behaviour was different from that above freezing point. At higher deuterium pressures the rate dropped abruptly at 273 K. Below the temperature the apparent activation energy was 54 kJ mol -1 and the exchange rate depended not on the deuterium pressure but on the amount of the pre-adsorbed water. At lower pressures, however, the kinetic behaviour was the same as the above 273 K, till the rate of the supply of deuterium from the gas phase exceeded the supply of hydrogen from adsorbed water to platinum surface. These results suggest that below 273 K the supply of hydrogen is markedly retarded, the state of the adsorbed water differing from that above 273 K. It was also demonstrated that when the adsorbed water is in the state of capillary condensation, the exchange rate becomes very small. (auth.)

  19. Preparation and Evaluation of Adsorbents from Coal and Irvingia gabonensis Seed Shell

    Science.gov (United States)

    Ezeokonkwo, Mercy A.; Ofor, Okechukwu F.; Ani, Julius U.

    2017-12-01

    The adsorption of Cd(II) and Pb(II) ions on adsorbents prepared from sub-bituminous coal, lignite and a blend of coal and Irvingia gabonensis seed shells was investigated. Fourier transform infrared, scanning electron microscope and X-ray fluorescence analyses implicated hydroxyl, carbonyl, Al2O3 and SiO2 as being responsible for binding the metal ions on the porous adsorbents. The optimum adsorption of carbonized lignite for the removal of Cd(II) and Pb(II) ions from aqueous media were 80.93% and 87.85%, respectively. Batch adsorption was done by effect of adsorbent dosage, pH, contact time, temperature, particle size, and initial concentration. Equilibrium for the removal of Pb(II) and Cd(II) was established within 100 and 120 min respectively. Blending the lignite-derived adsorbent with Irvingia gabonensis seed shell improved the performance significantly. More improvement was observed on modification of the blend using NaOH and H3PO4. Pb(II) was preferentially adsorbed than Cd(II) in all cases. Adsorption of Cd(II) and Pb(II) ions followed Langmuir isotherm. The kinetics of adsorption was best described by pseudo-second order model. The potential for using a blend of coal and agricultural byproduct (Irvingia gabonensis seed shell) was found to be a viable alternative for removal of toxic heavy metals from aqueous solutions.

  20. Radioactive diffusion gaseous probe technique for study adsorbent structure inhomogeneity

    International Nuclear Information System (INIS)

    Zyuzin, A.Yu.; Korobkov, V.I.; Bekman, I.N.

    1990-01-01

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

  1. A lumped-parameter model for cryo-adsorber hydrogen storage tank

    Energy Technology Data Exchange (ETDEWEB)

    Senthil Kumar, V.; Raghunathan, K. [India Science Lab, General Motors R and D, Creator Building, International Technology Park, Bangalore 560066 (India); Kumar, Sudarshan [Chemical and Environmental Sciences Lab, General Motors R and D, 30500 Mound Road, Warren, MI 48090 (United States)

    2009-07-15

    One of the primary requirements for commercialization of hydrogen fuel-cell vehicles is the on-board storage of hydrogen in sufficient quantities. On-board storage of hydrogen by adsorption on nano-porous adsorbents at around liquid nitrogen temperatures and moderate pressures is considered viable and competitive with other storage technologies: liquid hydrogen, compressed gas, and metallic or complex hydrides. The four cryo-adsorber fuel tank processes occur over different time scales: refueling over a few minutes, discharge over a few hours, dormancy over a few days, and venting over a few weeks. The slower processes i.e. discharge, dormancy and venting are expected to have negligible temperature gradients within the bed, and hence are amenable to a lumped-parameter analysis. Here we report a quasi-static lumped-parameter model for the cryo-adsorber fuel tank, and discuss the results for these slower processes. We also describe an alternative solution method for dormancy and venting based on the thermodynamic state description. (author)

  2. Coal and Zea mays cob waste as adsorbents for removal of metallic ...

    African Journals Online (AJOL)

    The efficiency of coal (CO) and Zea mays (ZM) cob adsorbents for the removal of metallic ions from wastewater is reported. The adsorbents were used in both their granular (GCO and GZM) and powdered (PCO and PZM) forms respectively. Chromium, nickel, iron and cadmium were used as model ions. Efficiency of the ...

  3. Synthesis of magnetic ordered mesoporous carbon (Fe-OMC) adsorbent and its evaluation for fuel desulfurization

    International Nuclear Information System (INIS)

    Farzin Nejad, N.; Shams, E.; Amini, M.K.

    2015-01-01

    In this work, magnetic ordered mesoporous carbon adsorbent was synthesized using soft templating method to adsorb sulfur from model oil (dibenzothiophene in n-hexane). Through this research, pluronic F-127, resorcinol-formaldehyde and hydrated iron nitrate were respectively used as soft template, carbon source and iron source. The adsorbent was characterized by X-ray diffraction, nitrogen adsorption–desorption isotherm and transmission electron microscopy. Nitrogen adsorption–desorption measurement revealed the high surface area (810 m 2 g −1 ), maxima pore size of 3.3 nm and large pore volume (1.01 cm 3 g −1 ) of the synthesized sample. The adsorbent showed a maximum adsorption capacity of 111 mg dibenzothiophene g −1 of adsorbent. Sorption process was described by the pseudo-second-order rate equation and could be better fitted by the Freundlich model, showing the heterogeneous feature of the adsorption process. In addition, the adsorption capacity of regenerated adsorbent was 78.6% of the initial level, after five regeneration cycles. - Highlights: • Adsorptive desulfurization of model oil with magnetic ordered mesoporous carbon adsorbent, Fe-OMC, was studied. • Maximum adsorption capacity (q max ) of Fe-OMC for DBT was found to be 111.1 mg g −1 . • Freundlich isotherm best represents the equilibrium adsorption data. • Rate of DBT adsorption process onto Fe-OMC is controlled by at least two steps

  4. Selective cesium removal from radioactive liquid waste by crown ether immobilized new class conjugate adsorbent.

    Science.gov (United States)

    Awual, Md Rabiul; Yaita, Tsuyoshi; Taguchi, Tomitsugu; Shiwaku, Hideaki; Suzuki, Shinichi; Okamoto, Yoshihiro

    2014-08-15

    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. Copyright © 2014 Elsevier B.V. All rights reserved.

  5. Double-Layer Structured CO2 Adsorbent Functionalized with Modified Polyethyleneimine for High Physical and Chemical Stability.

    Science.gov (United States)

    Jeon, Sunbin; Jung, Hyunchul; Kim, Sung Hyun; Lee, Ki Bong

    2018-06-18

    CO 2 capture using polyethyleneimine (PEI)-impregnated silica adsorbents has been receiving a lot of attention. However, the absence of physical stability (evaporation and leaching of amine) and chemical stability (urea formation) of the PEI-impregnated silica adsorbent has been generally established. Therefore, in this study, a double-layer impregnated structure, developed using modified PEI, is newly proposed to enhance the physical and chemical stabilities of the adsorbent. Epoxy-modified PEI and diepoxide-cross-linked PEI were impregnated via a dry impregnation method in the first and second layers, respectively. The physical stability of the double-layer structured adsorbent was noticeably enhanced when compared to the conventional adsorbents with a single layer. In addition to the enhanced physical stability, the result of simulated temperature swing adsorption cycles revealed that the double-layer structured adsorbent presented a high potential working capacity (3.5 mmol/g) and less urea formation under CO 2 -rich regeneration conditions. The enhanced physical and chemical stabilities as well as the high CO 2 working capacity of the double-layer structured adsorbent were mainly attributed to the second layer consisting of diepoxide-cross-linked PEI.

  6. Magnetic susceptibility of oxygen adsorbed on the surface of spherical and fibrous activated carbon.

    Directory of Open Access Journals (Sweden)

    Kiyoshi Kawamura

    2009-02-01

    Full Text Available The magnetic susceptibilities of oxygen adsorbed on the surface of bead-shaped activated carbon and activated carbon fibers were evaluated as a function of temperature between 4.2 K and 300 K, and found to exhibit a sharp peak at around 50 K. This implies that the adsorbed oxygen molecules form an antiferromagnetic state. The relation between the susceptibility and the adsorbed mass suggest that the thickness of the adsorbed oxygen is thin enough to consider a two-dimensional structure for bead–shaped activated carbon and carbon fibers across the fiber axis but thick enough to regard it as three-dimensional along the fiber axis. The result is discussed with reference to the study on one-dimensional oxygen array.

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

    International Nuclear Information System (INIS)

    Kenny, T.W.

    1989-05-01

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

  8. Rotary adsorbers for waste air purification and solvent recovery

    International Nuclear Information System (INIS)

    Konrad, G.; Eigenberger, G.

    1994-01-01

    Rotary Adsorbers for Waste Air Purification and Solvent Recovery. Thanks to their compact construction and low pressure drops, adsorbers with rotating adsorbent beds are highly suitable both for retrofitting of waste air purification units and generally for the removal of absorbable components from gas streams. When used in conjunction with straightforward hot gas desorption they permit almost complete purification of gas flows with concomitant concentration of the separated components in the desorbate by a factor of 10 to 20. They can also be used in conjunction with recovery of the separated components by partial condensation of the desorbate. Owing to the fixed coupling of adsorption and desorption times, which is determined by the geometry of the unit, the behaviour of the system is distinctly different from that of conventional multiple bed systems in cyclic operation. A detailed model description and computer simulation of operating behaviour are particularly useful for their analysis. It is shown that the behaviour of commercially available rotor concepts can be much better understood in this way and new concepts for exhaust air purification with integrated solvent recovery can be developed which are characterised by significantly reduced energy requirements for desorption and condensation. (orig.) [de

  9. The Adsorption of Cr(VI Using Chitosan-Alumina Adsorbent

    Directory of Open Access Journals (Sweden)

    Darjito Darjito

    2013-12-01

    Full Text Available Chitosan as adsorbent has been used widely, however it was not effective yet for metal ions adsorption in industrial scale. In acidic condition, chitosan’s active site tends to decrease. This drawback can was solved by coating of chitosan active site on alumina. This paper discloses to overcome that limitation. The charateristic of the active side was analysed by FTIR spectrometry toward vibration N-H group at 1679.15 cm-1, C=O group of oxalate at 1703.30 cm-1, and Al-O group of alumina at 924.07 cm-1. The adsorption capacity of the developed adsorbent was tester to adsorb Cr(VI ions under various of pH value such as 1, 2, 3, 4, 5, 6, and 7. The contact time affect toward the adsorption was also reported in 20, 30, 40 50, 60, 70, and 80 minute. In addition, the concentration effects (100, 200, 300, 400, 500, and 600 ppm was also studied. Chromium (VI was measured using spectronic-20. Adsorption capacity was obtained at 66.90 mg/g under optimum conditions pH 2, and contact time 60 minute, respectively.

  10. Radiation-induced reactions in D, L-α-alanine adsorbed in solid surfaces

    International Nuclear Information System (INIS)

    Aguilar, E; Negrón-Mendoza, A.; Camargo, C.

    2013-01-01

    The aim of this work is to study the behavior under irradiation of D, L and D-L α-alanine adsorbed in solid surfaces, as possible phase in the chemical evolution that may have occurred on the primitive Earth or in extraterrestrial environments and to evaluate the contribution of solids (a clay mineral) as shields for the adsorbed amino acids against a external energy source. The results show that α-alanine is adsorbed in the surfaces as function of pH and its yield of decomposition in mineral suspension is lower than the system without the solid surface. These results show the importance of nuclear techniques in these types of studies. (author)

  11. Influence of adsorbed carbon dioxide on hydrogen electrosorption in palladium-platinum-rhodium alloys

    International Nuclear Information System (INIS)

    Lukaszewski, M.; Grden, M.; Czerwinski, A.

    2004-01-01

    Carbon dioxide electroreduction was applied to examine the processes of hydrogen electrosorption (adsorption, absorption and desorption) by thin electrodeposits of Pd-Pt-Rh alloys under conditions of cyclic voltammetric (CV) experiments. Due to different adsorption characteristics towards the adsorption product of the electroreduction of CO 2 (reduced CO 2 ) exhibited by the alloy components hydrogen adsorption and hydrogen absorption signals can be distinguished on CV curves. Reduced CO 2 causes partial blocking of hydrogen adsorbed on surface Pt and Rh atoms, without any significant effect on hydrogen absorption into alloy. It reflects the fact that adsorbed hydrogen bonded to Pd atoms does not participate in CO 2 reduction, while hydrogen adsorbed on Pt and Rh surface sites is inactive in the absorption reaction. In contrast, CO is adsorbed on all alloy components and causes a marked inhibition of hydrogen sorption (both adsorption and absorption)/desorption reactions

  12. pyIAST: Ideal adsorbed solution theory (IAST) Python package

    Science.gov (United States)

    Simon, Cory M.; Smit, Berend; Haranczyk, Maciej

    2016-03-01

    Ideal adsorbed solution theory (IAST) is a widely-used thermodynamic framework to readily predict mixed-gas adsorption isotherms from a set of pure-component adsorption isotherms. We present an open-source, user-friendly Python package, pyIAST, to perform IAST calculations for an arbitrary number of components. pyIAST supports several common analytical models to characterize the pure-component isotherms from experimental or simulated data. Alternatively, pyIAST can use numerical quadrature to compute the spreading pressure for IAST calculations by interpolating the pure-component isotherm data. pyIAST can also perform reverse IAST calculations, where one seeks the required gas phase composition to yield a desired adsorbed phase composition.

  13. Preparation and characterization of a novel electrospun ammonium molybdophosphate/polyacrylonitrile nanofiber adsorbent for cesium removal

    International Nuclear Information System (INIS)

    Amin Tabatabaeefar; Mohammad Ali Moosavian; Ali Reza Keshtkar

    2015-01-01

    Adsorption of Cs + ion from aqueous solution onto a novel electrospun ammonium molybdophosphate/polyacrylonitrile nanofiber adsorbent with variation in AMP content, adsorbent concentration, pH, contact time, initial concentration and temperature was studied. The physicochemical characterization was performed by FTIR, XRD, BET and SEM analyses. Langmuir, Freundlich and Dubinin-Radushkevich models were used for analysis of equilibrium data. Kinetic results showed that the experimental data best fitted the pseudo-second-order kinetic model. The adsorption affinity of metal ions onto adsorbent was in order of Cs + > Co 2+ > Mg 2+ > Ca 2+ > Sr 2+ . The adsorbent could be easily regenerated after five cycles of adsorption-desorption. (author)

  14. Removal of phenol from aqueous solution using rice straw as adsorbent

    Science.gov (United States)

    Sarker, Nandita; Fakhruddin, A. N. M.

    2017-06-01

    Phenol is an environmental pollutant; the present study was conducted to examine the adsorption of phenol by rice straw. For this purpose raw (untreated), physically treated (boiled and dried) and thermally treated (heated at 230 °C for 3 h to produce ash) rice straw were selected to determine phenol removal efficiency at different contact times and adsorbent dosages for 1 and Percentage of removal of phenol increased as the adsorbent dose increase. The removal efficiency increase in the order of: raw rice straw ash) rice straw. Langmuir and Freundlich isotherm was developed for 1 and ash) treated rice straw. Freundlich isotherm best fit the equilibrium data for 1 mm thermally treated rice straw. The results showed that thermally treated rice straw (ash) can be developed as a potential adsorbent for phenol removal from aqueous solution.

  15. Spin-polarized transport properties of Fe atomic chain adsorbed on zigzag graphene nanoribbons

    International Nuclear Information System (INIS)

    Zhang, Z L; Chen, Y P; Xie, Y E; Zhang, M; Zhong, J X

    2011-01-01

    The spin-polarized transport properties of Fe atomic chain adsorbed on zigzag graphene nanoribbons (ZGNRs) are investigated using the density-functional theory in combination with the nonequilibrium Green's function method. We find that the Fe chain has drastic effects on spin-polarized transport properties of ZGNRs compared with a single Fe atom adsorbed on the ZGNRs. When the Fe chain is adsorbed on the centre of the ZGNR, the original semiconductor transforms into metal, showing a very wide range of spin-polarized transport. Particularly, the spin polarization around the Fermi level is up to 100%. This is because the adsorbed Fe chain not only induces many localized states but also has effects on the edge states of ZGNR, which can effectively modulate the spin-polarized transports. The spin polarization of ZGNRs is sensitive to the adsorption site of the Fe chain. When the Fe chain is adsorbed on the edge of ZGNR, the spin degeneracy of conductance is completely broken. The spin polarization is found to be more pronounced because the edge state of one edge is destroyed by the additional Fe chain. These results have direct implications for the control of the spin-dependent conductance in ZGNRs with the adsorption of Fe chains.

  16. Investigations into the Effect of Current Velocity on Amidoxime-Based Polymeric Uranium Adsorbent Performance

    Energy Technology Data Exchange (ETDEWEB)

    Gill, Gary A. [Pacific Northwest National Lab. (PNNL), Sequim, WA (United States). Marine Sciences Lab.; Kuo, Li-Jung [Pacific Northwest National Lab. (PNNL), Sequim, WA (United States). Marine Sciences Lab.; Strivens, Jonathan E. [Pacific Northwest National Lab. (PNNL), Sequim, WA (United States). Marine Sciences Lab.; Wood, Jordana R. [Pacific Northwest National Lab. (PNNL), Sequim, WA (United States). Marine Sciences Lab.; Schlafer, Nicholas J. [Pacific Northwest National Lab. (PNNL), Sequim, WA (United States). Marine Sciences Lab.; Tsouris, Costas [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Environmental Sciences Division; Ladshaw, Austin [Georgia Inst. of Technology, Atlanta, GA (United States); Yiacoumi, Sotira [Georgia Inst. of Technology, Atlanta, GA (United States)

    2015-12-01

    The Fuel Resources Program at the U.S. Department of Energy’s (DOE), Office of Nuclear Energy (DOE-NE) is developing adsorbent technology to extract uranium from seawater. This technology is being developed to provide a sustainable and economically viable supply of uranium fuel for nuclear reactors (DOE, 2010). Among the key environmental variables to understand for adsorbent deployment in the coastal ocean is what effect flow-rates or linear velocity has on uranium adsorption capacity. The goal is to find a flow conditions that optimize uranium adsorption capacity in the shortest exposure time. Understanding these criteria will be critical in choosing a location for deployment of a marine adsorbent farm. The objective of this study was to identify at what linear velocity the adsorption kinetics for uranium extraction starts to drop off due to limitations in mass transport of uranium to the surface of the adsorbent fibers. Two independent laboratory-based experimental approaches using flow-through columns and recirculating flumes for adsorbent exposure were used to assess the effect of flow-rate (linear velocity) on the kinetic uptake of uranium on amidoxime-based polymeric adsorbent material. Time series observations over a 56 day period were conducted with flow-through columns over a 35-fold range in linear velocity from 0.29 to 10.2 cm/s, while the flume study was conducted over a narrower 11-fold range, from 0.48 to 5.52 cm/s. These ranges were specifically chosen to focus on the lower end of oceanic currents and expand above and below the linear velocity of ~ 2.5 cm/s adopted for marine testing of adsorbent material at PNNL.

  17. Characteristics of Microorganism's Fouling on Lithium Adsorbents in Okgye Harbor, Gangneung, Korea

    Science.gov (United States)

    Kim, J.; Yoon, H.; Kong, M.; Yoon, B.; Ryu, J.; Chung, K.; Kim, B.

    2013-12-01

    Marine microorganisms bring about serious ramification for nautical industry such as marine construction. Interaction of bacteria and phytoplankton causes biofouling to marine environments. To understand the marine microorganism's reaction on the inorganic surface, the experimental work carried out in pilot plant for lithium recovery field at Okgye Harbor, Gangneung, Korea through seasonal interval. To inquiry into the surface's effect for lithium recovery adsorbents by bacterial communities and phytoplankton, disk type inorganic adsorbents were immersed in same site at depth of 5 m for 7 days, 14 days and 21 days. Culturable marine bacteria were isolated and identified by 16S rRNA sequencing. Also, size and shape of marine organisms and the adsorption circumstance were investigated by SEM and CLSM (confocal laser scanning microscope). At longer exposure time of adsorbents, increase the bacterial number of individual. Vibrio sp., represented dominant species of biofouling after 21 days and marine phytoplankton increased 7 times after 7 days. Size of phytoplankton were about 50 ~ 100 μm in 0.25 mm2 area of lithium adsorbents. To increase lithium recovery rate of lithium adsorbents and to minimize the biofouling effects, it is necessary to conduct consistently field monitoring. Acknowledgments This research was supported by the national research project titled 'The Development of Technology for Extraction of Resources Dissolved in Seawater' of the Korea Institute of Geoscience and Mineral Resources (KIGAM) funded by the Ministry of Ocean and Fisheries.

  18. Removal of lead and zinc ions from water by low cost adsorbents.

    Science.gov (United States)

    Mishra, P C; Patel, R K

    2009-08-30

    In this study, activated carbon, kaolin, bentonite, blast furnace slag and fly ash were used as adsorbent with a particle size between 100 mesh and 200 mesh to remove the lead and zinc ions from water. The concentration of the solutions prepared was in the range of 50-100 mg/L for lead and zinc for single and binary systems which are diluted as required for batch experiments. The effect of contact time, pH and adsorbent dosage on removal of lead and zinc by adsorption was investigated. The equilibrium time was found to be 30 min for activated carbon and 3h for kaolin, bentonite, blast furnace slag and fly ash. The most effective pH value for lead and zinc removal was 6 for activated carbon. pH value did not effect lead and zinc removal significantly for other adsorbents. Adsorbent doses were varied from 5 g/L to 20 g/L for both lead and zinc solutions. An increase in adsorbent doses increases the percent removal of lead and zinc. A series of isotherm studies was undertaken and the data evaluated for compliance was found to match with the Langmuir and Freundlich isotherm models. To investigate the adsorption mechanism, the kinetic models were tested, and it follows second order kinetics. Kinetic studies reveals that blast furnace slag was not effective for lead and zinc removal. The bentonite and fly ash were effective for lead and zinc removal.

  19. Synthesis of magnetic ordered mesoporous carbon (Fe-OMC) adsorbent and its evaluation for fuel desulfurization

    Energy Technology Data Exchange (ETDEWEB)

    Farzin Nejad, N., E-mail: Farzinnejadn@ripi.ir [Petroleum Refining Technology Development Division, Research Institute of Petroleum Industry, Tehran 14857-33111 (Iran, Islamic Republic of); Shams, E.; Amini, M.K. [Department of Chemistry, University of Isfahan, Isfahan 81746-73441 (Iran, Islamic Republic of)

    2015-09-15

    In this work, magnetic ordered mesoporous carbon adsorbent was synthesized using soft templating method to adsorb sulfur from model oil (dibenzothiophene in n-hexane). Through this research, pluronic F-127, resorcinol-formaldehyde and hydrated iron nitrate were respectively used as soft template, carbon source and iron source. The adsorbent was characterized by X-ray diffraction, nitrogen adsorption–desorption isotherm and transmission electron microscopy. Nitrogen adsorption–desorption measurement revealed the high surface area (810 m{sup 2} g{sup −1}), maxima pore size of 3.3 nm and large pore volume (1.01 cm{sup 3} g{sup −1}) of the synthesized sample. The adsorbent showed a maximum adsorption capacity of 111 mg dibenzothiophene g{sup −1} of adsorbent. Sorption process was described by the pseudo-second-order rate equation and could be better fitted by the Freundlich model, showing the heterogeneous feature of the adsorption process. In addition, the adsorption capacity of regenerated adsorbent was 78.6% of the initial level, after five regeneration cycles. - Highlights: • Adsorptive desulfurization of model oil with magnetic ordered mesoporous carbon adsorbent, Fe-OMC, was studied. • Maximum adsorption capacity (q{sub max}) of Fe-OMC for DBT was found to be 111.1 mg g{sup −1}. • Freundlich isotherm best represents the equilibrium adsorption data. • Rate of DBT adsorption process onto Fe-OMC is controlled by at least two steps.

  20. Eliminating Heavy Metals from Water with NanoSheet Minerals as Adsorbents

    Directory of Open Access Journals (Sweden)

    Shaoxian Song

    2017-12-01

    Full Text Available Heavy metals usually referred to those with atomic weights ranging from 63.5 to 200.6. Because of natural-mineral dissolution and human activities such as mining, pesticides, fertilizer, metal planting and batteries manufacture, etc., these heavy metals, including zinc, copper, mercury, lead, cadmium and chromium have been excessively released into water courses, like underground water, lake and river, etc. The ingestion of the heavy metals-contaminated water would raise serious health problems to human beings even at a low concentration. For instance, lead can bring human beings about barrier to the normal function of kidney, liver and reproductive system, while zinc can cause stomach cramps, skin irritations, vomiting and anemia. Mercury is a horrible neurotoxin that may result in damages to the central nervous system, dysfunction of pulmonary and kidney, chest and dyspnea. Chromium (VI has been proved can cause many diseases ranging from general skin irritation to severe lung carcinoma. Accordingly, the World Health Organization announced the maximum contaminant levels (MCL for the heavy metals in drinking water. There are numerous processes for eliminating heavy metals from water in order to provide citizens safe drinking water, including precipitation, adsorption, ion exchange, membrane separation and biological treatment, etc. Adsorption is considered as a potential process for deeply removing heavy metals, in which the selection of adsorbents plays a predominant role. Nano-sheet minerals as the adsorbents are currently the hottest researches in the field. They are obtained from layered minerals, such as montmorillonite, graphite and molybdenite, through the processing of intercalation, electrochemical and mechanical exfoliation, etc. Nano-sheet minerals are featured by their large specific surface area, relatively low costs and active adsorbing sites, leading to be effective and potential adsorbents for heavy metals removal from water

  1. Dimensionless groups for multidimensional heat and mass transfer in adsorbed natural gas storage

    Energy Technology Data Exchange (ETDEWEB)

    Sphaier, L.A. [Universidade Federal Fluminense (UFF), Niteroi, RJ (Brazil). Programa de Pos-Graduacao em Engenharia Mecanica. Lab. de Mecanica Teorica e Aplicada], E-mail: lasphaier@mec.uff.br

    2010-07-01

    This paper provides a new methodology for analyzing heat and mass transfer in gas storage via adsorption. The foundation behind the proposed methodology comprises a set of physically meaningful dimensionless groups. A discussion regarding the development of such groups is herein presented, providing a fully normalized multidimensional formulation for describing the transport mechanisms involved in adsorbed gas storage. After such presentation, data from previous literature studies associated with the problem of adsorbed natural gas storage are employed for determining realistic values for the developed parameters. Then, a one-dimensional test-case problem is selected for illustrating the application of the dimensionless formulation for simulating the operation of adsorbed gas reservoirs. The test problem is focused on analyzing an adsorbed gas discharge operation. This problem is numerically solved, and the solution is verified against previously published literature data. The presented results demonstrate how a higher heat of sorption values lead to reduced discharge capacities. (author)

  2. Fruit waste adsorbent for ammonia nitrogen removal from synthetic solution: Isotherms and kinetics

    Science.gov (United States)

    Zahrim, AY; Lija, Y.; Ricky, L. N. S.; Azreen, I.

    2016-06-01

    In this study, four types of watermelon rind (WR) adsorbents; fresh WR, modified WR with sodium hydroxide (NaOH), potassium hydroxide (KOH) and sulphuric acid (H2SO4) were used as a potential low-cost adsorbent to remove NH3-N from solution. The adsorption data were fitted with the adsorption isotherm and kinetic models to predict the mechanisms and kinetic characteristics of the adsorption process. The equilibrium data agreed well with Langmuir isotherm model with highest correlation (R2=1.00). As for kinetic modelling, the adsorption process follows pseudo-second order for all four types of adsorbents which has R2 value of 1.0 and calculated adsorption capacity, Qe of 1.2148mg/g. The calculated Qe for pseudo-second order has the smallest difference with the experimental Qe and thus suggest that this adsorption process is mainly governed by chemical process involving cations sharing or exchange between WR adsorbent and NH3-N in the solution.

  3. Structural Changes of Silica Mesocellular Foam Supported Amine-Functionalized CO 2 Adsorbents Upon Exposure to Steam

    KAUST Repository

    Li, Wen

    2010-11-24

    Three classes of amine-functionalized mesocellular foam (MCF) materials are prepared and evaluated as CO2 adsorbents. The stability of the adsorbents under steam/air and steam/nitrogen conditions is investigated using a Parr autoclave reactor to simulate, in an accelerated manner, the exposure that such adsorbents will see under steam stripping regeneration conditions at various temperatures. The CO2 capacity and organic content of all adsorbents decrease after steam treatment under both steam/air and steam/nitrogen conditions, primarily due to structural collapse of the MCF framework, but with additional contributions likely associated with amine degradation during treatment under harsh conditions. Treatment with steam/air is found to have stronger effect on the CO2 capacity of the adsorbents compared to steam/nitrogen. © 2010 American Chemical Society.

  4. Structural Changes of Silica Mesocellular Foam Supported Amine-Functionalized CO 2 Adsorbents Upon Exposure to Steam

    KAUST Repository

    Li, Wen; Bollini, Praveen; Didas, Stephanie A.; Choi, Sunho; Drese, Jeffrey H.; Jones, Christopher W.

    2010-01-01

    Three classes of amine-functionalized mesocellular foam (MCF) materials are prepared and evaluated as CO2 adsorbents. The stability of the adsorbents under steam/air and steam/nitrogen conditions is investigated using a Parr autoclave reactor to simulate, in an accelerated manner, the exposure that such adsorbents will see under steam stripping regeneration conditions at various temperatures. The CO2 capacity and organic content of all adsorbents decrease after steam treatment under both steam/air and steam/nitrogen conditions, primarily due to structural collapse of the MCF framework, but with additional contributions likely associated with amine degradation during treatment under harsh conditions. Treatment with steam/air is found to have stronger effect on the CO2 capacity of the adsorbents compared to steam/nitrogen. © 2010 American Chemical Society.

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

    Energy Technology Data Exchange (ETDEWEB)

    Abbasi, Afshin

    2010-02-22

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

  6. Complexation of lysozyme with adsorbed PtBS-b-SCPI block polyelectrolyte micelles on silver surface.

    Science.gov (United States)

    Papagiannopoulos, Aristeidis; Christoulaki, Anastasia; Spiliopoulos, Nikolaos; Vradis, Alexandros; Toprakcioglu, Chris; Pispas, Stergios

    2015-01-20

    We present a study of the interaction of the positively charged model protein lysozyme with the negatively charged amphiphilic diblock polyelectrolyte micelles of poly(tert-butylstyrene-b-sodium (sulfamate/carboxylate)isoprene) (PtBS-b-SCPI) on the silver/water interface. The adsorption kinetics are monitored by surface plasmon resonance, and the surface morphology is probed by atomic force microscopy. The micellar adsorption is described by stretched-exponential kinetics, and the micellar layer morphology shows that the micelles do not lose their integrity upon adsorption. The complexation of lysozyme with the adsorbed micellar layers depends on the micelles arrangement and density in the underlying layer, and lysozyme follows the local morphology of the underlying roughness. When the micellar adsorbed amount is small, the layers show low capacity in protein complexation and low resistance in loading. When the micellar adsorbed amount is high, the situation is reversed. The adsorbed layers both with or without added protein are found to be irreversibly adsorbed on the Ag surface.

  7. Electrospun chitosan/baker's yeast nanofibre adsorbent: preparation ...

    Indian Academy of Sciences (India)

    poration, complexation, reverse osmosis and membrane pro- cesses [2–4]. ... activities and some human activities such as exploitation of uranium and ... bre adsorbent for U(VI) and Th(IV) removal from aqueous solutions. 2. Experimental ..... Adsorption capacity of uranium(VI) and thorium(IV) in binary systems. where. H.

  8. Heterogeneous membranes filled with hypercrosslinked microparticle adsorbent

    Czech Academy of Sciences Publication Activity Database

    Hradil, Jiří; Krystl, V.; Hrabánek, P.; Bernauer, B.; Kočiřík, Milan

    2005-01-01

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

  9. Selective cesium removal from radioactive liquid waste by crown ether immobilized new class conjugate adsorbent

    OpenAIRE

    Awual, M. R.; 矢板 毅; 田口 富嗣; 塩飽 秀啓; 鈴木 伸一; 岡本 芳浩

    2014-01-01

    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 DB24C8 onto inorganic mesoporous silica. The obtained results revealed that adsorbent had higher selectivity towards C...

  10. Scattering of atoms by molecules adsorbed at solid surfaces

    International Nuclear Information System (INIS)

    Parra, Zaida.

    1988-01-01

    The formalism of collisional time-correlation functions, appropriate for scattering by many-body targets, is implemented to study energy transfer in the scattering of atoms and ions from molecules adsorbed on metal surfaces. Double differential cross-sections for the energy and angular distributions of atoms and ions scattered by a molecule adsorbed on a metal surface are derived in the limit of impulsive collisions and within a statistical model that accounts for single and double collisions. They are found to be given by the product of an effective cross-section that accounts for the probability of deflection into a solid angle times a probability per unit energy transfer. A cluster model is introduced for the vibrations of an adsorbed molecule which includes the molecular atoms, the surface atoms binding the molecule, and their nearest neighbors. The vibrational modes of CO adsorbed on a Ni(001) metal surface are obtained using two different cluster models to represent the on-top and bridge-bonding situations. A He/OC-Ni(001) potential is constructed from a strongly repulsive potential of He interacting with the oxygen atom in the CO molecule and a van der Waals attraction accounting for the He interaction with the free Ni(001) surface. A potential is presented for the Li + /OC-Ni(001) where a coulombic term is introduced to account for the image force. Trajectory studies are performed and analyzed in three dimensions to obtain effective classical cross-sections for the He/OC-Ni(001) and Li + /OC-Ni(001) systems. Results for the double differential cross-sections are presented as functions of scattering angles, energy transfer and collisional energy. Temperature dependence results are also analyzed. Extensions of the approach and inclusion of effects such as anharmonicity, collisions at lower energies, and applications of the approach to higher coverages are discussed

  11. Characterization of Adsorbents for Cytokine Removal from Blood in an In Vitro Model.

    Science.gov (United States)

    Harm, Stephan; Gabor, Franz; Hartmann, Jens

    2015-01-01

    Cytokines are basic targets that have to be removed effectively in order to improve the patient's health status in treating severe inflammation, sepsis, and septic shock. Although there are different adsorbents commercially available, the success of their clinical use is limited. Here, we tested different adsorbents for their effective removal of cytokines from plasma and the resulting effect on endothelial cell activation. The three polystyrene divinylbenzene (PS-DVB) based adsorbents Amberchrom CG161c and CG300m and a clinically approved haemoperfusion adsorbent (HAC) were studied with regard to cytokine removal in human blood. To induce cytokine release from leucocytes, human blood cells were stimulated with 1 ng/ml LPS for 4 hours. Plasma was separated and adsorption experiments in a dynamic model were performed. The effect of cytokine removal on endothelial cell activation was evaluated using a HUVEC-based cell culture model. The beneficial outcome was assessed by measuring ICAM-1, E-selectin, and secreted cytokines IL-8 and IL-6. Additionally the threshold concentration for HUVEC activation by TNF-α and IL-1β was determined using this cell culture model. CG161c showed promising results in removing the investigated cytokines. Due to its pore size the adsorbent efficiently removed the key factor TNF-α, outperforming the commercially available adsorbents. The CG161c treatment reduced cytokine secretion and expression of cell adhesion molecules by HUVEC which underlines the importance of effective removal of TNF-α in inflammatory diseases. These results confirm the hypothesis that cytokine removal from the blood should approach physiological levels in order to reduce endothelial cell activation.

  12. Cu II Removal from Industrial Wastewater Using Low Cost Adsorbent

    Directory of Open Access Journals (Sweden)

    Salwa Hadi Ahmed

    2018-01-01

    Full Text Available Study the possibility of utilization of waste tires rubber ash (WTRA as a low-cost adsorbent and are available as a type of solid waste for the removal of copper ions from industrial wastewater. Depending on batch adsorption experiments, the effect of different parameters including pH, adsorbent dosage WTRA, contact time, initial concentration of the ion and shacking speed were studied. Results showed that the highest removal Cu+2 ions was 97.8% at pH equal to 6, 120 min contact time, dose WTRA 1.5 g/L, shacking speed 150 rpm. The experimental data were analyzed using the Freundlich and Langmuir isotherm models showed great compatibility with Langmuir model (R2=0.923. Adsorption kinetics was studied and the data was showed agree with Pseudo-first-order equation where the value of (kt=0.5115/min. The study also showed the possibility of using WTRA efficiently as adsorbent and low cost in the removal of copper ions from industrial waste water. DOI: http://dx.doi.org/10.25130/tjes.24.2017.17

  13. 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

  14. Filter-adsorber aging assessment

    Energy Technology Data Exchange (ETDEWEB)

    Winegardner, W.K. [Pacific Northwest Laboratory, Richland, WA (United States)

    1995-02-01

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

  15. Multiple sample setup for testing the hydrothermal stability of adsorbents in thermal energy storage applications

    International Nuclear Information System (INIS)

    Fischer, Fabian; Laevemann, Eberhard

    2015-01-01

    Thermal energy storage based on adsorption and desorption of water on an adsorbent can achieve high energy storage densities. Many adsorbents lose adsorption capacity when operated under unfavourable hydrothermal conditions during adsorption and desorption. The stability of an adsorbent against stressing hydrothermal conditions is a key issue for its usability in adsorption thermal energy storage. We built an experimental setup that simultaneously controls the hydrothermal conditions of 16 samples arranged in a matrix of four temperatures and four water vapour pressures. This setup allows the testing of potential adsorbents between temperatures of 50 °C and 350 °C and water vapour pressures of up to 32 kPa. A measurement procedure that allows the detection of the hydrothermal stability of an adsorbent after defined time spans has been designed. We verified the functionality of the multiple sample measurements with a microporous adsorbent, a zeolite NaMSX. The hydrothermal stability of this zeolite is tested by water uptake measurements. A standard deviation lower than 1% of the 16 samples for detecting the hydrothermal stability enables setting different conditions in each sample cell. Further, we compared the water uptake measurements by measuring their adsorption isotherms with the volumetric device BELSORP Aqua 3 from Bel Japan. (paper)

  16. Facile preparation of salt-tolerant anion-exchange membrane adsorber using hydrophobic membrane as substrate.

    Science.gov (United States)

    Fan, Jinxin; Luo, Jianquan; Chen, Xiangrong; Wan, Yinhua

    2017-03-24

    In this study, a polyvinylidene fluoride (PVDF) hydrophobic membrane with high mechanical property was used as substrate to prepare salt-tolerant anion-exchange (STAE) membrane adsorber. Effective hydrophilization and functionalization of PVDF membrane was realized via polydopamine (PDA) deposition, thus overcoming the drawbacks of hydrophobic substrates including poor water permeability, inert property as well as severe non-specific adsorption. The following polyallylamine (PAH) coupling was carried out at pH 10.0, where unprotonated amine groups on PAH chains were more prone to couple with PDA. This membrane adsorber could remain 75% of protein binding capacity when NaCl concentration increased from 0 to 150mM, while its protein binding capacity was independent of flow rate from 10 to 100 membrane volume (MV)/min due to its high mechanical strength (tensile strength: 43.58±2.30MPa). With 200mM NaCl addition at pH 7.5, high purity (above 99%) and high recovery (almost 100%) of Immunoglobulin G (IgG) were obtained when using the STAE membrane adsorber to separate IgG/human serum albumin (HSA) mixture, being similar to that without NaCl at pH 6.0 (both under the flow rate of 10-100MV/min). Finally, the reliable reusability was confirmed by five reuse cycles of protein binding and elution operations. In comparison with commercial membrane adsorber, the new membrane adsorber exhibited a better mechanical property, higher IgG polishing efficiency and reusability, while the protein binding capacity was lower due to less NH 2 density on the membrane. The outcome of this work not only offers a facile and effective approach to prepare membrane adsorbers based on hydrophobic membranes, but also demonstrates great potential of this new designed STAE membrane adsorbers for efficient monoclonal antibody (mAb) polishing. Copyright © 2017 Elsevier B.V. All rights reserved.

  17. Mercury removal from solution by superconducting magnetic separation with nanostructured magnetic adsorbents

    Energy Technology Data Exchange (ETDEWEB)

    Okamoto, T., E-mail: okamoto-takayuki@ed.tmu.ac.jp [Graduate School of Science and Engineering, Tokyo Metropolitan University, 1-1 Minami-Osawa, Hachioji, Tokyo 192-0397 (Japan); Tachibana, S.; Miura, O. [Graduate School of Science and Engineering, Tokyo Metropolitan University, 1-1 Minami-Osawa, Hachioji, Tokyo 192-0397 (Japan); Takeuchi, M. [Komazawa Jin Clinic, 1-19-8 Komazawa, Setagayaku, Tokyo 154-0012 (Japan)

    2011-11-15

    Recently, mercury Hg concentration in human blood increases due to expanding the global mercury contamination. Excess mercury bioaccumulation poses a significant health risk. In order to decrease mercury concentration in the environment and human blood, we have developed two different kinds of nanostructured magnetic adsorbents for mercury to apply them to superconducting magnetic separation instead of conventional filtration. One is magnetic beads (MBs) which have nanosize magnetite particles in the core and a lot of SH radicals on the surface to adsorb Hg ions effectively. MBs were developed mainly to remove mercury from human blood. The maximum amount of the adsorption for MBs is 6.3 mg/g in the solution in less than a minute. Dithiothreitol can easily remove mercury adsorbed to MBs, hence MBs can be reusable. The other is nanostructured magnetic activated carbon (MAC) which is activated carbon with mesopores and nanosize magnetite. The maximum amount of the adsorption for MAC is 38.3 mg/g in the solution. By heat-treatment mercury can be easily removed from MAC. We have studied superconducting magnetic separation using each adsorbent for mercury removal from solution.

  18. Removal of 4-Chlorophenol from Aqueous Solutions Using Graphene Oxide Nanoporous Adsorbent

    Directory of Open Access Journals (Sweden)

    akbar eslami

    2015-03-01

    Full Text Available In this study, graphene oxide was used as a nanostructured adsorbent with properties supposedly better than other common adsorbents to remove 4-chlorophenol from aqueous solutions. For this purpose, graphene oxide was initially synthesized using the Hummer's method and x-ray diffraction and scanning electron microscopy were employed to identify its morphology and structure. The variables involved in the absorption process (including 4-chlorophenol initial concentration, adsorbent dosage, and pH were investigated based on the one-factor-at-a-time method. Eventually, the data were confirmed against the Langmuir and Freundlich isotherms. It was found that the adsorption process reached equilibrium in 20 minutes. A dosage of 0.4 g/L graphene oxide at pH=8 brought about 90% removal of 10 mg/L 4-chlorophenol within 5 minutes. The adsorption isotherm was described well by the Langmuir isotherm model and the values for R2 and RL were recorded as 0.99 for and 0.34, respectively. Being a low cost and highly efficient process, the adsorption process using graphene oxide adsorbent may be recommended for the reduction and elimination of pollutants in the environment, especially those in aqueous solutions.

  19. Role of air bubbles overlooked in the adsorption of perfluorooctanesulfonate on hydrophobic carbonaceous adsorbents.

    Science.gov (United States)

    Meng, Pingping; Deng, Shubo; Lu, Xinyu; Du, Ziwen; Wang, Bin; Huang, Jun; Wang, Yujue; Yu, Gang; Xing, Baoshan

    2014-12-02

    Hydrophobic interaction has been considered to be responsible for adsorption of perfluorooctanesulfonate (PFOS) on the surface of hydrophobic adsorbents, but the long C-F chain in PFOS is not only hydrophobic but also oleophobic. In this study, for the first time we propose that air bubbles on the surface of hydrophobic carbonaceous adsorbents play an important role in the adsorption of PFOS. The level of adsorption of PFOS on carbon nanotubes (CNTs), graphite (GI), graphene (GE), and powdered activated carbon (PAC) decreases after vacuum degassing. Vacuum degassing time and pressure significantly affect the removal of PFOS by these adsorbents. After vacuum degassing at 0.01 atm for 36 h, the extent of removal of PFOS by the pristine CNTs and GI decreases 79% and 74%, respectively, indicating the main contribution of air bubbles to PFOS adsorption. When the degassed solution is recontacted with air during the adsorption process, the removal of PFOS recovers to the value obtained without vacuum degassing, further verifying the key role of air bubbles in PFOS adsorption. By theoretical calculation, the distribution of PFOS in air bubbles on the adsorbent surfaces is discussed, and a new schematic sorption model of PFOS on carbonaceous adsorbents in the presence of air bubbles is proposed. The accumulation of PFOS at the interface of air bubbles on the adsorbents is primarily responsible for its adsorption, providing a new mechanistic insight into the transport, fate, and removal of PFOS.

  20. Tetracycline removal from water by adsorption/bioadsorption on activated carbons and sludge-derived adsorbents.

    Science.gov (United States)

    Rivera-Utrilla, José; Gómez-Pacheco, Carla V; Sánchez-Polo, Manuel; López-Peñalver, Jesús J; Ocampo-Pérez, Raúl

    2013-12-15

    The objective of this study was to analyze the behavior of activated carbons with different chemical and textural natures in the adsorption of three tetracyclines (TCs) (tetracycline, oxytetracycline, and chlortetracycline). We also assessed the influence of the solution pH and ionic strength on the adsorption of these compounds and studied their removal by the combined use of microorganisms and activated carbon (bioadsorption). Sludge-derived materials were also used to remove TC from water. The capacity of these materials to adsorb TC was very high and was much greater than that of commercial activated carbon. This elevated adsorption capacity (512.1-672.0 mg/g) is explained by the high tendency of TC to form complex ions with some of the metal ions present in these materials. The medium pH and presence of electrolytes considerably affected TCs adsorption on commercial activated carbon. These results indicate that electrostatic adsorbent-adsorbate interactions play an important role in TC adsorption processes when conducted at pH values that produce TC deprotonation. The presence of bacteria during the TCs adsorption process decreases their adsorption/bioadsorption on the commercial activated carbon, weakening interactions between the adsorbate and the microfilm formed on the carbon surface. The adsorptive capacity was considerably lower in dynamic versus static regime, attributable to problems of TC diffusion into carbon pores and the shorter contact time between adsorbate and adsorbent. Copyright © 2013 Elsevier Ltd. All rights reserved.

  1. The application of textile sludge adsorbents for the removal of Reactive Red 2 dye.

    Science.gov (United States)

    Sonai, Gabriela G; de Souza, Selene M A Guelli U; de Oliveira, Débora; de Souza, Antônio Augusto U

    2016-03-01

    Sludge from the textile industry was used as a low-cost adsorbent to remove the dye Reactive Red 2 from an aqueous solution. Adsorbents were prepared through the thermal and chemical treatment of sludge originating from physical-chemical (PC) and biological (BIO) effluent treatment processes. The adsorbent characterization was carried out through physical-chemical analysis, X-ray fluorescence (XRF) spectroscopy, Fourier transform infrared (FTIR) spectroscopy, pHPZC determination, Boehm titration method, Brunauer-Emmett-Teller (BET) surface area analysis and scanning electron microscopy (SEM). Batch kinetic experiments and adsorption isotherm modeling were conducted under different pH and temperature conditions. The results for the kinetic studies indicate that the adsorption processes associated with these systems can be described by a pseudo-second-order model and for the equilibrium data the Langmuir model provided the best fit. The adsorption was strongly dependent on the pH but not on the temperature within the ranges studied. The maxima adsorption capacities were 159.3 mg g(-1) for the BIO adsorbent and 213.9 mg g(-1) for PC adsorbent at pH of 2 and 25 °C. Copyright © 2015 Elsevier Ltd. All rights reserved.

  2. Separation of Co(II) from dilute aqueous solutions by precipitate and adsorbing colloid flotation

    International Nuclear Information System (INIS)

    Aziz, M.; Benyamin, K.; Shakir, K.; Atomic Energy Establishment, Cairo

    1993-01-01

    Ion, precipitate and adsorbing colloid flotation of cobalt(II) have been investigated at different pH values, using N-dodecylpyridinium chloride (DPCl). A strong cationic surfactant, and sodium lauryl sulfate (NaLS), a strong anionic surfactant, as collectors. In case of adsorbing colloid flotation, hydrous manganese dioxide was used as an adsorbent. The precipitate flotation curves experimentally obtained with the two tested collectors were compared with the corresponding theoretical one calculated from the data published for Co(II) hydrolysis. The effects of the collector concentration, ageing of the water-MnO 2 -Co(II) system, bubbling time period, cobalt(II) concentration and foreign salts on the percent removal of Co(II) by adsorbing colloid flotation using DPCl as collector were determined. Removals approaching 100% could be achieved under the optimum conditions. (author) 44 refs.; 6 figs

  3. Determination of adsorbed protein concentration in aluminum hydroxide suspensions by near-infrared transmittance Spectroscopy

    DEFF Research Database (Denmark)

    Lai, Xuxin; Zheng, Yiwu; Jacobsen, Susanne

    2008-01-01

    , using the partial least square regression (PLSR) method to construct a calibration model. The linear concentration range of adsorbed BSA is from 0 to 1.75 mg/mL by using 10 mm path length cuvettes. The influence of the sedimentation in suspension, different buffers, and different aluminum hydroxide......Analysis of aluminum hydroxide based vaccines is difficult after antigen adsorption. Adsorbed protein is often assessed by measuring residual unadsorbed protein for quality control. A new method for the direct determination of adsorbed protein concentration in suspension using near-infrared (NIR......) transmittance spectroscopy is proposed here. A simple adsorption system using albumin from bovine serum (BSA) and aluminum hydroxide as a model system is employed. The results show that the NIR absorbance at 700-1300 nm is correlated to the adsorbed BSA concentration, measured by the ultraviolet (UV) method...

  4. 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.

  5. Distribution of metal and adsorbed guest species in zeolites

    International Nuclear Information System (INIS)

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

  6. Development of Molybdenum Adsorbent for 99Mo/99mTc Radioisotope Generator Based on Irradiated Natural Molybdenum

    International Nuclear Information System (INIS)

    Rohadi Awaludin; Hotman Lubis; Sriyono; Abidin; Herlina; Endang Sarmini; Indra Saptiama; Hambali

    2011-01-01

    Preparation of 99 Mo/ 99m Tc radioisotope generator using irradiated natural molybdenum requires an adsorbent with high absorption capacity. Zirconium-based materials (ZBM), adsorbent with adsorption capacity of about 183 mg(Mo) / g(adsorbent), has been successfully synthesized. However, the adsorbent was easily broken in the Mo adsorption process due to many fractures in the grain. To increase the hardness, the material was immersed in tetraethyl orthosilicate (TEOS) and coated by TEOS flow in a column. The hardness test results showed that the ZBM with TEOS treatment was not broken when immersed into the Mo solution. Observations using SEM showed that the fractures formed on the ZBM were successfully removed by TEOS treatment. Measurements using EDS showed that after TEOS treatment, the silicon was detected and the oxygen content increased in the material surface. Adsorption test results showed that the TEOS immersion decreased the adsorption capacity of molybdenum from 183 to 79.8 mg of Mo per gram of adsorbent. The TEOS flow-in a column gave material with relatively high adsorption capacity, 140 mgMo per gram adsorbent. The content of Silicon in the surface was lower than that of adsorbent immersed in TEOS. (author)

  7. First-principles study of pollutant molecules absorbed on polymeric adsorbents using the vdW-DF2 functional

    Science.gov (United States)

    Zhu, Jinguo; Wang, Yapeng; Tian, Ting; Zhang, Qianfan

    2018-03-01

    Polymeric adsorbents have been attracting increasing attention because of their favorable structrual properties and effectiveness of solving small molecules contaminants. However, due to the absence of deep insight into the adsorption mechanism of polymeric adsorbents, researches on new polymeric adsorbents can only be carried out by repeated experiments and tests, which is extremely inefficient. Therefore, investigating the adsorption process of polymeric adsorbents, especially the mechanism of adsorbing various air pollutant molecules by materials modelling and simulation, is of great significance. Here in this work, we systematically studied the adsorption mechanism by first-principles computation with van der Waals interaction. It demonstrates that the adsorption between them was pure physisorption originating from the hydrogen bond and intermolecular forces consisting of Keesom force, Debye force and London dispersion force. The proportions of these forces varied according to different adsorption systems. The adsorption effects were determined by the polymers’ dipole moment and polarizability. The adsorption performance of some polymers with special structures was also investigated to explore their possibility as potential adsorbents. The results of our simulation can provide some guidance for developing new polymeric adsorbents with better performance.

  8. From illite/smectite clay to mesoporous silicate adsorbent for efficient removal of chlortetracycline from water.

    Science.gov (United States)

    Wang, Wenbo; Tian, Guangyan; Zong, Li; Zhou, Yanmin; Kang, Yuru; Wang, Qin; Wang, Aiqin

    2017-01-01

    A series of mesoporous silicate adsorbents with superior adsorption performance for hazardous chlortetracycline (CTC) were sucessfully prepared via a facile one-pot hydrothermal reaction using low-cost illite/smectite (IS) clay, sodium silicate and magnesium sulfate as the starting materials. In this process, IS clay was "teared up" and then "rebuilt" as new porous silicate adsorbent with high specific surface area of 363.52m 2 /g (about 8.7 folds higher than that of IS clay) and very negative Zeta potential (-34.5mV). The inert SiOSi (Mg, Al) bonds in crystal framework of IS were broken to form Si(Al) O - groups with good adsorption activity, which greatly increased the adsorption sites served for holding much CTC molecules. Systematic evaluation on adsorption properties reveals the optimal silicate adsorbent can adsorb 408.81mg/g of CTC (only 159.7mg/g for raw IS clay) and remove 99.3% (only 46.5% for raw IS clay) of CTC from 100mg/L initial solution (pH3.51; adsorption temperature 30°C; adsorbent dosage, 3g/L). The adsorption behaviors of CTC onto the adsorbent follows the Langmuir isotherm model, Temkin equation and pseudo second-order kinetic model. The mesopore adsorption, electrostatic attraction and chemical association mainly contribute to the enhanced adsorption properties. As a whole, the high-efficient silicate adsorbent could be candidates to remove CTC from the wastewater with high amounts of CTC. Copyright © 2016. Published by Elsevier B.V.

  9. Synthesis of Hydrophilic Sulfur-Containing Adsorbents for Noble Metals Having Thiocarbonyl Group Based on a Methacrylate Bearing Dithiocarbonate Moieties

    Directory of Open Access Journals (Sweden)

    Haruki Kinemuchi

    2018-01-01

    Full Text Available Novel hydrophilic sulfur-containing adsorbents for noble metals were prepared by the radical terpolymerization of a methacrylate bearing dithiocarbonate moieties (DTCMMA, hydrophilic monomers, and a cross-linker. The resulting adsorbents efficiently and selectively adsorbed noble metals (Au, Ag, and Pd from various multielement aqueous solutions at room temperature owing to the thiocarbonyl group having high affinity toward noble metals. The metal adsorption by the adsorbents was proceeded by simple mixing followed by filtration. The noble metal selectivity of the adsorbent obtained from DTCMMA and N-isopropylacrylamide was higher than that of the adsorbent obtained from DTCMMA and N,N-dimethylacrylamide due to the lower nonspecific adsorption.

  10. Radiolysis of alanine adsorbed in a clay mineral

    Energy Technology Data Exchange (ETDEWEB)

    Aguilar-Ovando, Ellen Y.; Negron-Mendoza, Alicia [Instituto de Ciencias Nucleares, Universidad Nacional Autonoma de Mexico (UNAM), Circuito Exterior s/n, Ciudad Universitaria, Apartado Postal 70-543, Deleg. Coyoacan, C.P. 04510 (Mexico)

    2013-07-03

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

  11. Radiolysis of alanine adsorbed in a clay mineral

    International Nuclear Information System (INIS)

    Aguilar-Ovando, Ellen Y.; Negrón-Mendoza, Alicia

    2013-01-01

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

  12. Investigation of Adsorbed Gases Content in Coal Beds in Bosnia and Herzegovina

    Directory of Open Access Journals (Sweden)

    Sadadinovic, J.

    2008-09-01

    Full Text Available Investigation of the gas fraction in coal beds in Bosnia & Herzegovina has been performed systematically since 1988. Gas in coal beds can be present in free or adsorbed form, and dissolved in water. Methods of investigation are based on the direct approach, according to which the gas fraction is determined in the undisturbed coal bed.The quantity of the adsorbed and free gas in the coal bed is directly proportional to the gas pressure. Dependence is hyperbolic. The quantity of the free gas in mining conditions is being determined by measurement of the desorption index (Δp2. The desorption index for the Srednjobosanski coal basin ranges to 1571 Pa, and the free gas pressure in this coal basin amounts up to 3.75 MPa. The desorption index for coal beds in “Kreka” and “Banoviće” coal basins has negative values, which means that the free gas fraction within the coal beds is negligible, while separation of adsorbed gases is diffuse. The free gas pressure in the mentioned coal basins is below 0.1 MPa. Adsorbed gases within the coal are connected by physical adsorption according to Langmuir’s isothermal adsorption curve. Langmuir’s quantities, for coal bed conditions, ranges as follows: am from 0.826 to 9.52 m3 t–1 pcs, and b from 6.65 10–3 to 0.247 MPa–1. Adsorbed gas within Miocene coal beds contains methane in amounts of 1.49 m3 t–1 čus CH4 andcarbon(IVoxide in amounts of 0.15 m3 t–1 čus CO2. Adsorbed gas within Pliocene coal beds, without methane, dominant is content of carbon(IVoxide.The investigation of the gas content in coal beds of BiH conducted in this article reveal that the coal beds primarily contain methane, while others hydrocarbons such as ethane, ethene, propane, propene and butane are present sporadically in fraction below φ/10–6. Based on the investigation results conducted in this article, simple mathematical forms were obtained for quick calculation of the free gas quantity by measurement of the

  13. Characterisation of phase transition in adsorbed monolayers at the air/water interface.

    Science.gov (United States)

    Vollhardt, D; Fainerman, V B

    2010-02-26

    Recent work has provided experimental and theoretical evidence that a first order fluid/condensed (LE/LC) phase transition can occur in adsorbed monolayers of amphiphiles and surfactants which are dissolved in aqueous solution. Similar to Langmuir monolayers, also in the case of adsorbed monolayers, the existence of a G/LE phase transition, as assumed by several authors, is a matter of question. Representative studies, at first performed with a tailored amphiphile and later with numerous other amphiphiles, also with n-dodecanol, provide insight into the main characteristics of the adsorbed monolayer during the adsorption kinetics. The general conditions necessary for the formation of a two-phase coexistence in adsorbed monolayers can be optimally studied using dynamic surface pressure measurements, Brewster angle microscopy (BAM) and synchrotron X-ray diffraction at grazing incidence (GIXD). A characteristic break point in the time dependence of the adsorption kinetics curves indicates the phase transition which is largely affected by the concentration of the amphiphile in the aqueous solution and on the temperature. Formation and growth of condensed phase domains after the phase transition point are visualised by BAM. As demonstrated by a tailored amphiphile, various types of morphological textures of the condensed phase can occur in different temperature regions. Lattice structure and tilt angle of the alkyl chains in the condensed phase of the adsorbed monolayer are determined using GIXD. The main growth directions of the condensed phase textures are correlated with the two-dimensional lattice structure. The results, obtained for the characteristics of the condensed phase after a first order main transition, are supported by experimental bridging to the Langmuir monolayers. Phase transition of adsorbing trace impurities in model surfactants can strongly affect the characteristics of the main component. Dodecanol present as minor component in aqueous sodium

  14. Recycling of spent adsorbents for oxyanions and heavy metal ions in the production of ceramics.

    Science.gov (United States)

    Verbinnen, Bram; Block, Chantal; Van Caneghem, Jo; Vandecasteele, Carlo

    2015-11-01

    Spent adsorbents for oxyanion forming elements and heavy metals are classified as hazardous materials and they are typically treated by stabilization/solidification before landfilling. The use of lime or cement for stabilization/solidification entails a high environmental impact and landfilling costs are high. This paper shows that mixing spent adsorbents in the raw material for the production of ceramic materials is a valuable alternative to stabilize oxyanion forming elements and heavy metals. The produced ceramics can be used as construction material, avoiding the high economic and environmental impact of stabilization/solidification followed by landfilling. To study the stabilization of oxyanion forming elements and heavy metals during the production process, two series of experiments were performed. In the first series of experiments, the main pollutant, Mo was adsorbed onto iron-based adsorbents, which were then mixed with industrial sludge (3 w/w%) and heated at 1100°C for 30 min. Mo was chosen, as this element is easily adsorbed onto iron-based adsorbents and it is the element that is the most difficult to stabilize (i.e. the highest temperatures need to be reached before the concentrations in the leachate are reduced). Leaching concentration from the 97/3 sludge/adsorbent mixture before heating ranged between 85 and 154 mg/kg; after the heating process they were reduced to 0.42-1.48 mg/kg. Mo was actually stabilized, as the total Mo concentration after addition was not affected by the heat treatment. In the second series of experiments, the sludge was spiked with other heavy metals and oxyanion forming elements (Cr, Ni, Cu, Zn, As, Cd and Pb) in concentrations 5 times higher than the initial concentrations; after heat treatment the leachate concentrations were below the regulatory limit values. The incorporation of spent adsorbents in ceramic materials is a valuable and sustainable alternative to the existing treatment methods, saving raw materials in the

  15. Chitosan-edible oil based materials as upgraded adsorbents for textile dyes.

    Science.gov (United States)

    Dos Santos, Clayane Carvalho; Mouta, Rodolpho; Junior, Manoel Carvalho Castro; Santana, Sirlane Aparecida Abreu; Silva, Hildo Antonio Dos Santos; Bezerra, Cícero Wellington Brito

    2018-01-15

    Biopolymer chitosan is a low cost, abundant, environmentally friendly, very selective and efficient anionic dyes adsorbent, being a promising material for large-scale removal of dyes from wastewater. However, raw chitosan (CS) is an ineffective cationic dyes adsorbent and its performance is pH sensitive, thus, CS modifications that address these issues need to be developed. Here, we report the preparation and characterization of two new CS modifications using edible oils (soybean oil or babassu oil), and their adsorption performance for two dyes, one anionic (remazol red, RR) and one cationic (methylene blue, MB). Both modifications extended the pH range of RR adsorption. The babassu oil modification increased adsorption capacity of the cationic dye MB, whereas the soybean oil modification increased that of RR. Such improvements demonstrate the potential of these two new CS modifications as adsorbent candidates for controlling dyes pollution in effluents. Copyright © 2017 Elsevier Ltd. All rights reserved.

  16. Development of a computationally-designed polymeric adsorbent specific for mycotoxin patulin.

    Science.gov (United States)

    Piletska, Elena V; Pink, Demi; Karim, Kal; Piletsky, Sergey A

    2017-12-04

    Patulin is a toxic compound which is found predominantly in apples affected by mould rot. Since apples and apple-containing products are a popular food for the elderly, children and babies, the monitoring of the toxin is crucial. This paper describes a development of a computationally-designed polymeric adsorbent for the solid-phase extraction of patulin, which provides an effective clean-up of the food samples and allows the detection and accurate quantification of patulin levels present in apple juice using conventional chromatography methods. The developed bespoke polymer demonstrates a quantitative binding towards the patulin present in undiluted apple juice. The polymer is inexpensive and easy to mass-produce. The contributing factors to the function of the adsorbent is a combination of acidic and basic functional monomers producing a zwitterionic complex in the solution that formed stronger binding complexes with the patulin molecule. The protocols described in this paper provide a blueprint for the development of polymeric adsorbents for other toxins or different food matrices.

  17. Adsorbate Diffusion on Transition Metal Nanoparticles

    Science.gov (United States)

    2015-01-01

    correlation is a Bronsted-Evans-Polanyi ( BEP )- type of correlation, similar to other BEP correlations established earlier for surface-catalyzed bond- breaking...bond-making reactions.6-9 The universal BEP -type correlation is independent of the nature of the adsorbed species and that of the metal surface. For...a certain class of surface-catalyzed reactions, the existence of a BEP -type correlation reflects a similarity between the geometry of the transition

  18. Adsorption Characteristics of Different Adsorbents and Iron(III Salt for Removing As(V from Water

    Directory of Open Access Journals (Sweden)

    Josip Ćurko

    2016-01-01

    Full Text Available The aim of this study is to determine the adsorption performance of three types of adsorbents for removal of As(V from water: Bayoxide® E33 (granular iron(III oxide, Titansorb® (granular titanium oxide and a suspension of precipitated iron(III hydroxide. Results of As(V adsorption stoichiometry of two commercial adsorbents and precipitated iron(III hydroxide in tap and demineralized water were fitted to Freundlich and Langmuir adsorption isotherm equations, from which adsorption constants and adsorption capacity were calculated. The separation factor RL for the three adsorbents ranged from 0.04 to 0.61, indicating effective adsorption. Precipitated iron(III hydroxide had the greatest, while Titansorb had the lowest capacity to adsorb As(V. Comparison of adsorption from tap or demineralized water showed that Bayoxide and precipitated iron(III hydroxide had higher adsorption capacity in demineralized water, whereas Titansorb showed a slightly higher capacity in tap water. These results provide mechanistic insights into how commonly used adsorbents remove As(V from water.

  19. Comparison with adsorption of Re (VII) by two different γ-radiation synthesized silica-grafting of vinylimidazole/4-vinylpyridine adsorbents

    Energy Technology Data Exchange (ETDEWEB)

    Xiao, Pu [Beijing Key Laboratory for Solid Waste Utilization and Management, Department of Energy and Resources Engineering, College of Engineering, Peking University, Beijing 100871,China (China); Han, Dong; Zhai, Maolin [Beijing National Laboratory for Molecular Sciences, Radiochemistry and Radiation Chemistry Key Laboratory of Fundamental Science, The Key Laboratory of Polymer Chemistry and Physics of the Ministry of Education, College of Chemistry and Molecular Engineering, Peking University, Beijing 100871 (China); Xu, Ling, E-mail: lingxu@pku.edu.cn [Beijing Key Laboratory for Solid Waste Utilization and Management, Department of Energy and Resources Engineering, College of Engineering, Peking University, Beijing 100871,China (China); Li, Huibo, E-mail: hb0012@sina.com [China Institute of Atomic Energy, P.O. Box 275-26, Beijing 102413 (China)

    2017-02-15

    Highlights: • Two Re adsorbents were synthesized by grafting of vinylimidazole and vinylpyridine onto silanized silica gel via γ-radiation. • The Re adsorption capacities of SS-MPTS-VIMH and SS-MPTS-VPQ were 145.99 mg g{sup −1} and 71.08 mg g{sup −1}, respectively. • Both the adsorbents had fast adsorption kinetics, and could be used for column adsorption. • SS-MPTS-VPQ had good anti-interference abilities, and might be used for the disposal of Tc in the future. - Abstract: Two silica gel based adsorbents for Re (VII), i.e. SS-MPTS-VIMH and SS-MPTS-VPQ, were synthesised. Silica gel was used as the matrix for γ-radiation grafting, and the monomer of 1-vinyl imidazole (VIM) and 4-vinylpyridine (4-VP) was grafted onto the silica silanized by methacryloxy propyl trimethoxyl silane, respectively. A VIM concentration of 2 mol L{sup −1} and an absorbed dose of 30 kGy were the optimal grafting conditions for adsorbent SS-MPTS-VIM, and a 4-VP concentration of 4 mol L{sup −1} and an absorbed dose of 40 kGy were the optimal grafting conditions for adsorbent SS-MPTS-VP. At the certain condition, the grafting yield of SS-MPTS-VIM was 30.1% and that of SS-MPTS-VP was 21.0%. The adsorption capacity of adsorbent SS-MPTS-VIMH was 145.99 mg g{sup −1} and that of SS-MPTS-VPQ was 71.08 mg g{sup −1} according to the Langmuir model. The adsorbent SS-MPTS-VPQ had better adsorption properties of acid resistance and anti-interference than SS-MPTS-VIMH. Dynamic column experiments showed that protonated adsorbent SS-MTPS-VIMH could be recycled with good performance while quaternized adsorbent SS-MPTS-VPQ could not. The adsorbent SS-MPTS-VIMH belongs to weak anion exchange adsorbent and SS-MPTS-VPQ belongs to strong anion exchange adsorbent. This study paves a way to the synthesis and application of a novel silica base adsorbents for Re (VII).

  20. 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.

  1. WGS-Adsorbent Reaction Studies at Laboratory Scale; Estudios de la Reaccion WGS-Adsorbente a Escala de Laboratorio

    Energy Technology Data Exchange (ETDEWEB)

    Marano, M.; Torreiro, Y.

    2014-02-01

    This document reports the most significant results obtained during the experimental work performed under task WGS-adsorbent experimental studies within CAPHIGAS project (National Research Plan 2008-2011, ref: ENE2009-08002). The behavior of the binary adsorbent-catalyst system which will be used in the hybrid system is described in this document. Main results reported here were used during the design and development of the hybrid system adsorbent catalyst- membrane proposed in the CAPHIGAS project. The influence of main operating parameters and the optimized volume ratio adsorbent-catalyst are also presented in this report. (Author)

  2. Structure analysis of adsorbed star-like polymers with GISAS and SFM

    CERN Document Server

    Wolkenhauer, M; Wunnicke, O; Stamm, M; Roovers, J; Krosigk, G V; Cubitt, R

    2002-01-01

    The lateral structures of dried adsorbed binary mixtures of star polymers were investigated. Blends of protonated and deuterated polybutadiene stars were prepared from cyclohexane solutions and adsorbed onto silicon substrates. The number of arms and the molecular weight of the arms was varied. With grazing incidence small angle scattering techniques (GISAS) and scanning force microscopy (SFM), different dominant in-plane length scales were determined. The morphology of these structures is dominated by blob-like structures created from single stars or agglomerates of star polymers. (orig.)

  3. 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%.

  4. Amine-tethered solid adsorbents coupling high adsorption capacity and regenerability for CO2 capture from ambient air.

    Science.gov (United States)

    Choi, Sunho; Gray, McMahan L; Jones, Christopher W

    2011-05-23

    Silica supported poly(ethyleneimine) (PEI) materials are prepared via impregnation and demonstrated to be promising adsorbents for CO(2) capture from ultra-dilute gas streams such as ambient air. A prototypical class 1 adsorbent, containing 45 wt% PEI (PEI/silica), and two new modified PEI-based aminosilica adsorbents, derived from PEI modified with 3-aminopropyltrimethoxysilane (A-PEI/silica) or tetraethyl orthotitanate (T-PEI/silica), are prepared and characterized by using thermogravimetric analysis and FTIR spectroscopy. The modifiers are shown to enhance the thermal stability of the polymer-oxide composites, leading to higher PEI decomposition temperatures. The modified adsorbents present extremely high CO(2) adsorption capacities under conditions simulating ambient air (400 ppm CO(2) in inert gas), exceeding 2 mol(CO (2)) kg(sorbent)(-1), as well as enhanced adsorption kinetics compared to conventional class 1 sorbents. The new adsorbents show excellent stability in cyclic adsorption-desorption operations, even under dry conditions in which aminosilica adsorbents are known to lose capacity due to urea formation. Thus, the adsorbents of this type can be considered promising materials for the direct capture of CO(2) from ultra-dilute gas streams such as ambient air. Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  5. A novel starch-based adsorbent for removing toxic Hg(II) and Pb(II) ions from aqueous solution.

    Science.gov (United States)

    Huang, Li; Xiao, Congming; Chen, Bingxia

    2011-08-30

    A novel effective starch-based adsorbent was prepared through two common reactions, which included the esterification of starch with excess maleic anhydride in the presence of pyridine and the cross-linking reaction of the obtained macromonomer with acrylic acid by using potassium persulphate as initiator. The percentage of carboxylic groups of the macromonomer ranged from 14% to 33.4%. The cross-linking degree of the adsorbent was tailored with the amount of acrylic acid which varied from 10wt% to 80wt%. Both Fourier transform infrared spectra and thermogravimetric analysis results verified the structure of the adsorbent. The maximum gel fraction and swelling ratio of the adsorbent were about 72% and 6.25, respectively, and they were able to be adjusted with the amount of monomers. The weight loss percentage of the adsorbent could reach 96.9% after immersing in the buffer solution that contained α-amylase for 14h. It was found that the adsorption capacities of the adsorbent for lead and mercury ions could be 123.2 and 131.2mg/g, respectively. In addition, the adsorbent was able to remove ca. 51-90% Pb(II) and Hg(II) ions that existed in the decoctions of four medicinal herbals. Copyright © 2011 Elsevier B.V. All rights reserved.

  6. Application of adsorbent as a novel technique during ...

    African Journals Online (AJOL)

    STORAGESEVER

    2008-09-17

    Sep 17, 2008 ... hydrophilic compound (carbon), thermally activated at temperatures of 300, 500, 700 and ... carbon in microbial degradation of anthracene, elicits an enhanced disappearance rate of the ... persistence, toxicity and their tendency to bioaccumulate ... paper therefore, investigates the use of adsorbent (acti-.

  7. Order-disorder transitions in adsorbed systems on magnetic surfaces

    International Nuclear Information System (INIS)

    Aguilera-Granja, F.; Moran-Lopez, J.L.; Instituto Politecnico Nacional, Mexico City. Centro de Investigacion y de Estudios Avanzados); Falicov, L.M.

    1984-01-01

    It is investigated the effect of adsorbed atoms on the magnetic properties of ferromagnets. The Ising model is employed considering nearest neigbours with antiferromagnetic coupling between atoms. (M.W.O.) [pt

  8. Manganese-modified activated carbon fiber (Mn-ACF): Novel efficient adsorbent for Arsenic

    Energy Technology Data Exchange (ETDEWEB)

    Sun, Zhumei; Yu, Yichang; Pang, Shiyu; Du, Dongyun, E-mail: dydu666@yahoo.com.cn

    2013-11-01

    In this paper, a novel adsorbent, manganese-modified activated carbon fiber (Mn-ACF), was prepared and used for removal of As(V) from aqueous solution. The adsorbent was characterized by scanning electron microscopy (SEM) and X-ray photoelectron spectroscopy (XPS). Adsorption of As(V) onto the as-prepared adsorbent from aqueous solutions was investigated and discussed. The adsorption kinetic data were modeled using the pseudo-first-order and pseudo-second order, respectively. The experimental results indicate that the pseudo-second-order kinetic equation can better describe the adsorption kinetics. Furthermore, adsorption equilibrium data of As(V) on the as-prepared adsorbent were analyzed by Langmuir and Freundlich models, which suggested that the Langmuir model provides a better correlation of the experimental data. The adsorption capacities (q{sub max}) of As(V) on Mn-ACF at various temperatures, determined using the Langmuir equation, are 23.77, 33.23 and 36.53 mg g{sup −1} at 303, 313 and 323 K, respectively. To the best of our knowledge, this adsorption capacity for As(V) is much larger than those reported in literatures (7.50–16.58 mg g{sup −1}). Notably, the q{sub max} increases with increasing temperature, suggesting that adsorption of As(V) on Mn-ACF surface is an endothermic process, which is further confirmed by the calculated thermodynamic parameters including free energy, enthalpy, and entropy of adsorption process. The effect of experimental parameters such as pH and dosage of adsorbent on adsorption of As(V) were also studied. The present work will be useful in purification of groundwater.

  9. Characterization and Cadmium Ion-Removing Property of Adsorbents Synthesized from Inorganic Wastes

    Energy Technology Data Exchange (ETDEWEB)

    Ooishi, Kou; Ogino, Kana; Nishioka, Hiroshi; Muramatsu, Yasuji, E-mail: hnisioka@eng.u-hyogo.ac.jp [Department of Material Science and Chemistry, Graduate School of Engineering, University of Hyogo, 2167 Shosha, Himeji, Hyogo (Japan)

    2011-10-29

    Adsorbents for removing cadmium ions from water were synthesized from inorganic wastes such as oyster shells, drinking-water-treatment sludge (DWTS), and waste glass. The oyster shells and DWTS were pretreated by heating for 2 h at 1173 K before hydrothermal synthesis was started. The Al/(Al+Si) ratio was adjusted, and then, the mixture of pretreated materials was hydrothermally treated in a sodium hydroxide solution for 72 h at 423 K to synthesize the adsorbents. The synthesized adsorbent specimens were characterized by X-ray diffraction (XRD), thermogravimetric-differential thermal analysis (TG-DTA) measurements, and scanning electron microscopy (SEM). The main components of these specimens were aluminum-substituted tobermorite and sodalite. The formation of sodalite was dependent on the mass ratio of DWTS to glass. The maximum amount of cadmium ions were removed when the mass ratio of the pretreated material was 1:1:1. In the cadmium removal test, the adsorbent with this mass ratio removed almost 100% of the cadmium in a solution with a concentration of 10 mg L-1. Even in the presence of a 1000-fold excess of potassium ions or 10000-fold excess of sodium ions, approximately 80% of the cadmium ions were removed.

  10. Many-body dispersion effects in the binding of adsorbates on metal surfaces

    Energy Technology Data Exchange (ETDEWEB)

    Maurer, Reinhard J. [Department of Chemistry, Yale University, New Haven, Connecticut 06520 (United States); Ruiz, Victor G.; Tkatchenko, Alexandre [Fritz-Haber-Institut der Max-Planck-Gesellschaft, Faradayweg 4-6, D-14195 Berlin (Germany)

    2015-09-14

    A correct description of electronic exchange and correlation effects for molecules in contact with extended (metal) surfaces is a challenging task for first-principles modeling. In this work, we demonstrate the importance of collective van der Waals dispersion effects beyond the pairwise approximation for organic–inorganic systems on the example of atoms, molecules, and nanostructures adsorbed on metals. We use the recently developed many-body dispersion (MBD) approach in the context of density-functional theory [Tkatchenko et al., Phys. Rev. Lett. 108, 236402 (2012) and Ambrosetti et al., J. Chem. Phys. 140, 18A508 (2014)] and assess its ability to correctly describe the binding of adsorbates on metal surfaces. We briefly review the MBD method and highlight its similarities to quantum-chemical approaches to electron correlation in a quasiparticle picture. In particular, we study the binding properties of xenon, 3,4,9,10-perylene-tetracarboxylic acid, and a graphene sheet adsorbed on the Ag(111) surface. Accounting for MBD effects, we are able to describe changes in the anisotropic polarizability tensor, improve the description of adsorbate vibrations, and correctly capture the adsorbate–surface interaction screening. Comparison to other methods and experiment reveals that inclusion of MBD effects improves adsorption energies and geometries, by reducing the overbinding typically found in pairwise additive dispersion-correction approaches.

  11. Linear response theory of activated surface diffusion with interacting adsorbates

    Energy Technology Data Exchange (ETDEWEB)

    Marti' nez-Casado, R. [Department of Chemistry, Imperial College London, South Kensington, London SW7 2AZ (United Kingdom); Sanz, A.S.; Vega, J.L. [Instituto de Fi' sica Fundamental, Consejo Superior de Investigaciones Cientificas, Serrano 123, 28006 Madrid (Spain); Rojas-Lorenzo, G. [Instituto Superior de Tecnologi' as y Ciencias Aplicadas, Ave. Salvador Allende, esq. Luaces, 10400 La Habana (Cuba); Instituto de Fi' sica Fundamental, Consejo Superior de Investigaciones Cienti' ficas, Serrano 123, 28006 Madrid (Spain); Miret-Artes, S., E-mail: s.miret@imaff.cfmac.csic.es [Instituto de Fi' sica Fundamental, Consejo Superior de Investigaciones Cienti' ficas, Serrano 123, 28006 Madrid (Spain)

    2010-05-12

    Graphical abstract: Activated surface diffusion with interacting adsorbates is analyzed within the Linear Response Theory framework. The so-called interacting single adsorbate model is justified by means of a two-bath model, where one harmonic bath takes into account the interaction with the surface phonons, while the other one describes the surface coverage, this leading to defining a collisional friction. Here, the corresponding theory is applied to simple systems, such as diffusion on flat surfaces and the frustrated translational motion in a harmonic potential. Classical and quantum closed formulas are obtained. Furthermore, a more realistic problem, such as atomic Na diffusion on the corrugated Cu(0 0 1) surface, is presented and discussed within the classical context as well as within the framework of Kramer's theory. Quantum corrections to the classical results are also analyzed and discussed. - Abstract: Activated surface diffusion with interacting adsorbates is analyzed within the Linear Response Theory framework. The so-called interacting single adsorbate model is justified by means of a two-bath model, where one harmonic bath takes into account the interaction with the surface phonons, while the other one describes the surface coverage, this leading to defining a collisional friction. Here, the corresponding theory is applied to simple systems, such as diffusion on flat surfaces and the frustrated translational motion in a harmonic potential. Classical and quantum closed formulas are obtained. Furthermore, a more realistic problem, such as atomic Na diffusion on the corrugated Cu(0 0 1) surface, is presented and discussed within the classical context as well as within the framework of Kramer's theory. Quantum corrections to the classical results are also analyzed and discussed.

  12. Type of adsorbent and column height in adsorption process of used cooking oil

    Science.gov (United States)

    Hasnelly, Hervelly, Taufik, Yusman; Melany, Ivo Nila

    2015-12-01

    The purpose of this research was to find out the best adsorbent and column height that can adsorb color and soluble impurities substances in used cooking oil. This research was meant for knowledge development of refined cooking oil technology. The used of this research was giving out information on the recycling process of used cooking oil. Research design used 2 × 2 factorial pattern in randomized group design with 6 repetitions. The first factor is adsorbent type (J) that consist of activated carbon (J1) and Zeolit (J2). The second factor is column height (K) with variations of 15 cm (k1) and 20 cm (k2). Chemical analysis parameter are free fatty acid, water content and saponification value. Physical parameter measurement was done on color with Hunter Lab system analysis and viscosity using viscometer method. Chemical analysis result of preliminary research on used cooking oil showed water content of 1,9%, free fatty acid 1,58%, saponification value 130,79 mg KOH/g oil, viscosity 0,6 d Pas and color with L value of -27,60, a value 1,04 and b value 1,54. Result on main research showed that adsorbent type only gave effect on water content whereas column height and its interaction was not gave significant effect on water content. Interaction between adsorbent type (J) and column height (K) gave significant effect to free fatty acid, saponification value, viscosity and color for L, a and b value of recycled cooking oil.

  13. Transient desorption characteristics of fibrous organic adsorbent; Sen'ikei yuki kyuchakuzai no katoteki dacchaku tokusei

    Energy Technology Data Exchange (ETDEWEB)

    Inaba, H.; Ozaki, K.; Horibe, A. [Okayama University, Okayama (Japan). Faculty of Engineering; Shimoyama, R. [Okayama University, Okayama (Japan); Kida, T. [Japan Exlan Co. Ltd., Osaka (Japan)

    1999-11-25

    An experimental investigation was performed to determine time transient desorption characteristics of a fibrous type organic adsorbent, which was composed of the bridged complex of sodium polyacrylate as a new kind of adsorbent. The test fibrous adsorbent was packed in a cylindrical vessel, and dry air was passed through it. The experiments were conducted under various conditions of air velocity, temperature, relative humidity and vessel length. As a result, time pressure loss for the packed bed of the test fibrous adsorbent showed a similar tendency to that for the packed bed of spherical particles. The mass transfer data was correlated by the modified Sherwood number, the Reynolds number, the Schmidt number, the ratio of desorbed water vapor mass to fibrous absorbent mass, the nondimensional temperature and the ratio of vessel length to fiber diameter. Fourier number for the nondimensional temperature and the ratio of desorbed water vapor mass to fibrous adsorbent mass, the nondimensional temperature and the ratio of vessel length to fiber diameter. (author)

  14. Numerical Study on the Contribution of Convective Mass Transfer Inside High-Porosity Adsorbents in the VOC Adsorption Process

    DEFF Research Database (Denmark)

    Zhang, Ge; He, Wenna; Fang, Lei

    2013-01-01

    The transfer mechanism of volatile organic compounds (VOCs) being trapped inside the various types of adsorbents is usually regarded as mere diffusion. This paper investigated the contribution of convective mass transfer inside the adsorbents used for VOC air-cleaning. The adsorbents are typically...

  15. Neutron scattering from adsorbed species

    International Nuclear Information System (INIS)

    Shuwang An

    1998-01-01

    Neutron reflection has been used to investigate the structure of layers of water-soluble diblock copolymers poly(2-(dimethylamino)ethyl methacrylate-block-methyl methacrylate (poly(DMAEMA-b-MMA)) (70 mol% DMAEMA, M n = 10k, 80 mol% DMAEMA, M n = 10k, and 70 mol% DMAEMA, M n = 20k) adsorbed at the air-liquid and solid-liquid interfaces. The surface tension behaviour of these copolymers at the air-liquid interface has also been investigated. The study of the structure of layers of poly(DMAEMA-b-MMA) adsorbed at the air-water interface forms the main part of the thesis. The surface structure, the effects of pH and ionic strength, and the effects of composition and molecular weight of the copolymers have been studied systematically. For the 70%-10k copolymer at pH 7.5, the adsorption isotherm shows that there is a surface phase transition. The concentration of copolymer at which the phase transition occurs is close to that at which micellar aggregation in the bulk solution also occurs. At low concentrations (below the CMC), the two blocks of the copolymer are approximately uniformly distributed in the direction normal to the interface and the layer is partially immersed in water. At high concentrations (above the CMC), the adsorbed layer has a cross-sectional structure resembling that expected for a micelle with the majority of the MMA blocks forming the core. The outer layers, comprising predominantly DMAEMA blocks, are not equivalent, being more highly extended on the aqueous side of the interface. The effects of pH and added electrolyte on the structure of layers of the 70%-10k copolymer show that the layered structure is promoted by any changes in the bulk solution that enhance the surface coverage but is inhibited by an increase in the fractional charge on the polyelectrolyte part of the copolymer. The effect of lowering the pH is to increase the positive charge on the weak polyelectrolyte block. Addition of electrolyte generally enhances the amount adsorbed and

  16. Bioavailability in rats of metal adsorbed to soils

    International Nuclear Information System (INIS)

    Rubenstein, R.; Griffin, S.; Irene, S.; DeRosa, C.; Choudhury, H.

    1990-01-01

    The toxicity of metals to humans and animals has been well documented, however little data are available on the physiological bioavailability of metals from various soil types. These studies were designed to assess the bioavailability of sodium 75 selenate (NaS), 63 nickel chloride (NiCl) and 109 cadmium chloride (CdCl) adsorbed to sand or clay loam in rats. Each test compound was administered in seven dose groups: Group 1 - intravenously, Group 2 and 3 - oral aqueous solution by gavage, Groups 4-7 - aqueous suspension adsorbed to each soil type by gavage. Blood was collected from the jugular vein at intervals up to 48 hours post dosing and analyzed for radio-activity. Both NiCl and CdCl were poorly adsorbed from the soils. Approximately 3% of the CdCl bound to sand and 1.5% of the NiCl bound to clay loam were absorbed into the bloodstream. Approximately 0.5% and 0.1% of the CdCl bound to sand and clay, respectively were absorbed. NaS was well absorbed following oral administration with approximately 85% of the compound bound to sand and 94% bound to clay being absorbed into the blood. Bioavailability of metals from soil appears to be primarily affected by the ionic state of the metal. Anions, such as selenium, are more mobile in an acid environment and may leach more readily from soil. Cations, such as Ni and Cd may bind to soil more tightly, thus soil type becomes a factor affecting bioavailability

  17. Adsorbate-induced lifting of substrate relaxation is a general mechanism governing titania surface chemistry.

    Science.gov (United States)

    Silber, David; Kowalski, Piotr M; Traeger, Franziska; Buchholz, Maria; Bebensee, Fabian; Meyer, Bernd; Wöll, Christof

    2016-09-30

    Under ambient conditions, almost all metals are coated by an oxide. These coatings, the result of a chemical reaction, are not passive. Many of them bind, activate and modify adsorbed molecules, processes that are exploited, for example, in heterogeneous catalysis and photochemistry. Here we report an effect of general importance that governs the bonding, structure formation and dissociation of molecules on oxidic substrates. For a specific example, methanol adsorbed on the rutile TiO 2 (110) single crystal surface, we demonstrate by using a combination of experimental and theoretical techniques that strongly bonding adsorbates can lift surface relaxations beyond their adsorption site, which leads to a significant substrate-mediated interaction between adsorbates. The result is a complex superstructure consisting of pairs of methanol molecules and unoccupied adsorption sites. Infrared spectroscopy reveals that the paired methanol molecules remain intact and do not deprotonate on the defect-free terraces of the rutile TiO 2 (110) surface.

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

    International Nuclear Information System (INIS)

    Abdallah, W.A.; Taylor, S.D.

    2007-01-01

    X-ray photoelectron spectroscopy was used to characterize a single layer of adsorbed asphaltene on a metallic surface. The deposits were created by immersing a stainless steel disc into a dilute asphaltene solution with either toluene or dichloromethane as the solvent, although the toluene solution allowed for better control of the adsorbed asphaltene layer and less atmospheric oxygen contamination. The analyses for C 1s, S 2p 3/2 , N 1s and O 1s photoemission peaks indicated that different functional groups are present in the asphaltene layer including carboxylic, pyrrolic, pyridininc, thiophenic and sulfite, with slight differences in their binding energies

  19. Structure of solid surfaces and of adsorbates by low-energy electron diffraction

    International Nuclear Information System (INIS)

    Somorjai, G.A.

    1977-01-01

    LEED theory has developed to the point where the diffraction beam intensities can be computed using the locations of the surface atoms as the only adjustable parameters. The position of atoms in many clean monatomic solid surfaces and the surface structures of ordered monolayers of adsorbed atoms have been determined this way. Surface crystallography studies are now extended to small hydrocarbon molecules that are adsorbed on metal surfaces. These studies are reviewed

  20. High temperature dielectric properties of spent adsorbent with zinc sulfate by cavity perturbation technique

    Energy Technology Data Exchange (ETDEWEB)

    Lin, Guo [State Key Laboratory of Complex Nonferrous Metal Resources Clean Utilization, Kunming University of Science and Technology, Kunming, Yunnan 650093 (China); Faculty of Metallurgical and Energy Engineering, Kunming University of Science and Technology, Kunming, Yunnan 650093 (China); Key Laboratory of Unconventional Metallurgy, Ministry of Education, Kunming, Yunnan 650093 (China); National Local Joint Laboratory of Engineering Application of Microwave Energy and Equipment Technology, Kunming, Yunnan 650093 (China); Liu, Chenhui [State Key Laboratory of Complex Nonferrous Metal Resources Clean Utilization, Kunming University of Science and Technology, Kunming, Yunnan 650093 (China); Key Laboratory of Unconventional Metallurgy, Ministry of Education, Kunming, Yunnan 650093 (China); National Local Joint Laboratory of Engineering Application of Microwave Energy and Equipment Technology, Kunming, Yunnan 650093 (China); Faculty of Chemistry and Environment, Yunnan Minzu University, Kunming, Yunnan 650093 (China); Zhang, Libo, E-mail: libozhang77@163.com [State Key Laboratory of Complex Nonferrous Metal Resources Clean Utilization, Kunming University of Science and Technology, Kunming, Yunnan 650093 (China); Faculty of Metallurgical and Energy Engineering, Kunming University of Science and Technology, Kunming, Yunnan 650093 (China); Key Laboratory of Unconventional Metallurgy, Ministry of Education, Kunming, Yunnan 650093 (China); National Local Joint Laboratory of Engineering Application of Microwave Energy and Equipment Technology, Kunming, Yunnan 650093 (China); and others

    2017-05-15

    Highlights: • Cavity perturbation technique is employed to measure the dielectric properties. • Microwave absorption capability of ZnO is poor from 20 °C to 850 °C. • Dielectric properties of spent absorbent and zinc sulfate are influenced by temperature especially in high temperature stage. • Penetration depths and heating curve indicate spent adsorbent and ZnO·2ZnSO{sub 4}, ZnSO{sub 4} are excellent microwave absorber. • The pore structures of spent adsorbent are improved significantly by microwave-regeneration directly. - Abstract: Dielectric properties of spent adsorbent with zinc sulfate are investigated by cavity perturbation technique at 2450 MHz from 20 °C to approximately 1000 °C. Two weight loss stages are observed for spent adsorbent by thermogravimetric-differential scanning calorimeter (TG-DSC) analysis, and zinc sulfate is decomposed to ZnO·2ZnSO{sub 4} and ZnO at about 750 °C and 860 °C. Microwave absorption capability of ZnSO{sub 4} increases with increasing temperature and declines after ZnO generation on account of the poor dielectric properties. Dielectric properties of spent adsorbent are dependent on apparent density and noticed an interestingly linearly relationship at room temperature. The three parameters increase gently from 20 °C to 400 °C, but a sharp increase both in real part and imaginary part are found subsequently due to the volatiles release and regeneration of carbon. And material conductivity is improved, which contributes to the π-electron conduction appearance. Relationship between penetration depth and temperature further elaborate spent adsorbent is an excellent microwave absorber and the microwave absorption capability order of zinc compounds is ZnO·2ZnSO{sub 4}, ZnSO{sub 4} and ZnO. Heating characteristics suggest that heating rate is related with dielectric properties of materials. The pore structures of spent adsorbent are improved significantly and the surface is smoother after microwave-regeneration.

  1. Generating Atomistic Slab Surfaces with Adsorbates

    Science.gov (United States)

    2017-12-01

    slabs of various thickness and with various vacuum spacing need be calculated. This can occur in serial or simultaneously . If performed in serial, the...the user. Although the optimization of the slab thickness and vacuum padding can be done simultaneously , it is more computationally conservative to...monolayer is a slab (True if slab), the type of mesh desired (adsorbates.py was written for “Gamma”), how detailed the mesh should be (in units of inverse

  2. Alginate Adsorbent Immobilization Technique Promotes Biobutanol Production by Clostridium acetobutylicum Under Extreme Condition of High Concentration of Organic Solvent

    Directory of Open Access Journals (Sweden)

    Zhuoliang Ye

    2018-05-01

    Full Text Available In Acetone-Butanol-Ethanol fermentation, bacteria should tolerate high concentrations of solvent products, which inhibit bacteria growth and limit further increase of solvents to more than 20 g/L. Moreover, this limited solvent concentration significantly increases the cost of solvent separation through traditional approaches. In this study, alginate adsorbent immobilization technique was successfully developed to assist in situ extraction using octanol which is effective in extracting butanol but presents strong toxic effect to bacteria. The adsorbent improved solvent tolerance of Clostridium acetobutylicum under extreme condition of high concentration of organic solvent. Using the developed technique, more than 42% of added bacteria can be adsorbed to the adsorbent. Surface area of the adsorbent was more than 10 times greater than sodium alginate. Scanning electron microscope image shows that an abundant amount of pore structure was successfully developed on adsorbents, promoting bacteria adsorption. In adsorbent assisted ABE fermentation, there was 21.64 g/L butanol in extracting layer compared to negligible butanol produced with only the extractant but without the adsorbent, for the reason that adsorbent can reduce damaging exposure of C. acetobutylicum to octanol. The strategy can improve total butanol production with respect to traditional culture approach by more than 2.5 fold and save energy for subsequent butanol recovery, which effects can potentially make the biobutanol production more economically practical.

  3. Negative chromatography of hepatitis B virus-like particle: Comparative study of different adsorbent designs.

    Science.gov (United States)

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

    2016-05-06

    Purification of virus-like particles (VLPs) in bind-and-elute mode has reached a bottleneck. Negative chromatography has emerged as the alternative solution; however, benchmark of negative chromatography media and their respective optimized conditions are absent. Hence, this study was carried out to compare the performance of different negative chromatography media for the purification of hepatitis B VLPs (HB-VLPs) from clarified Escherichia coli feedstock. The modified anion exchange media, core-shell adsorbents (InertShell and InertLayer 1000) and polymer grafted adsorbents (SQ) were compared. The results of chromatography from packed bed column of core-shell adsorbents showed that there is a trade-off between the purity and recovery of HB-VLPs in the flowthrough fraction due to the shell thickness. Atomic force microscopic analysis revealed funnel-shaped pore channels in the shell layer which may contribute to the entrapment of HB-VLPs. A longer residence time at a lower feed flow rate (0.5ml/min) improved slightly the HB-VLPs purity in all modified adsorbents, but the recovery in InertShell reduced substantially. The preheat-treatment is not recommended for the negative chromatography as the thermal-induced co-aggregation of HCPs and HB-VLPs would flow along with HB-VLPs and thus reduced the HB-VLPs purity in the flowthrough. Further reduction in the feedstock concentration enhanced the purity of HB-VLPs especially in InertLayer 1000 but reduced substantially the recovery of HB-VLPs. In general, the polymer grafted adsorbent, SQ, performed better than the core-shell adsorbents in handling a higher feedstock concentration. Copyright © 2016 Elsevier B.V. All rights reserved.

  4. Applicability of Sol-Gel Derived Adsorbent for the Production of (n,f) 99Mo Generator

    International Nuclear Information System (INIS)

    Lee, Jun-Sig; Lee, Jong-Sup; Park, Ul-Jae; Son, Kwang-Jae; Han, Hyon-Soo; Kim, Myung Sic; Koo, Sung Chan; Chung, Young-Ju

    2007-01-01

    High performance adsorbents as the column material for (n,γ) 99 Mo/ 99 mTc and 188 W/ 188 Re generators have been developed at KAERI. These adsorbents should have enough loading capacities to produce such generators with high activities as the loading isotopes are not carrier-free. In this regard, the adsorbents are synthesized by sol-gel processing in which the ligand density can easily be adjusted and maximized. The marginal capacity of such adsorbents should be higher than 200 mg/g for molybdenum. From the previous works, the sol-gel processing techniques are adequately applied to meet the criteria. Further studies are being undertaken to employ the adsorbents for the production of high capacity (n,f) 99 Mo/ 99 mTc. Domestically, a private company has lined up the production facility of the molybdenum generator in the activity range of 300 ∼ 1,000 mCi/ea. The column elements are composed of manganese oxide doped on silica and alumina at the backup layer. In this column, the manganese oxide is the main reactive layer to retain (n,f) 99 Mo. The sol-gel derived adsorbent, in this study, is employed as the replacement of the manganese oxide doped silica in the column and tested for the loading efficiency of (n,f) 99 Mo, elution of 99 mTc, labeling property of the eluted 99 mTc. The same loading and elution procedures as the commercial production are applied for the tests and quality controls

  5. 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.

  6. On the influence of adsorber performance on plant design for the extraction of uranium from seawater

    International Nuclear Information System (INIS)

    Koske, P.H.; Ohlrogge, K.

    1983-01-01

    Based on simple seawater and dissolved uranium balances the influence of specific adsorber parameters on size and design of production plants with fluidized adsorber beds for the extraction of uranium from seawater is discussed. Besides a critical review of two recently published plant designs in the USA and Japan experimentally determined adsorber data for a polyamidoxim (PAO) granulate are presented together with an evaluation of their influence on the key plant parameters. (orig.) [de

  7. 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. Copyright © 2012 Elsevier B.V. All rights reserved.

  8. Removal of Lead from Water Using Calcium Alginate Beads Doped with Hydrazine Sulphate-Activated Red Mud as Adsorbent

    Directory of Open Access Journals (Sweden)

    A. Naga Babu

    2017-01-01

    Full Text Available Calcium alginate beads doped with hydrazine sulphate-treated red mud are investigated as adsorbent for extracting lead ions from water using batch methods of extraction. Different extraction conditions are optimised for maximum lead extraction. Substantial amount of lead is removed, and the adsorption ability is found to be 138.6 mg/g. Surface characterization using FTIR, EDX, and FESEM confirms that lead is “onto” the surface of the adsorbent. Thermodynamic parameters, adsorption isotherms, and kinetics of adsorption are analysed. Adsorption is “physisorption” in nature and spontaneous. The adsorbent developed can be regenerated using 0.1 M HCl. Thus regenerated adsorbent can be used as the adsorbent for further removal of lead at least 10 times, and this enables the complete removal of lead from water by repetitive use of the regenerated adsorbent. The beads facilitate the easy filtration. The methodology developed is successfully applied for removing lead from industrial waste waters.

  9. New apparatus for measuring radon adsorption on solid adsorbents

    International Nuclear Information System (INIS)

    Hassan, N.M.; Hines, A.L.; Ghosh, T.K.; Loyalka, S.K.; Ketring, A.R.

    1991-01-01

    A new experimental system was designed to measure radon uptake by solid adsorbents from air or other carrier gases/vapors. The total amount of radon adsorbed corresponding to a specific gas-phase concentration was determined by simultaneously measuring the solid-phase and gas-phase concentrations. The system was used to measure radon adsorption isotherms on BPL activated carbon at 288, 298, and 308 K and on silica gel and molecular sieve 13X at 298 K. The isotherms were of type III according to Brunauer's classification. The heat of adsorption data indicated that the BPL activated carbon provided a heterogeneous surface for radon adsorption. The equilibrium data were correlated by the Freundlich equation. In this paper the possible adsorption mechanism and the use of the adsorption isotherms to measure indoor radon concentrations are discussed

  10. Application of new mycotoxin adsorbent-bentonite clay “Askangel” in poultry feed

    OpenAIRE

    A. Chkuaseli; M. Khutsishvili-Maisuradze; A. Chagelishvili; K. Natsvaladze; T. Lashkarashvili; G. Chagelishvili; N. Maisuradze

    2016-01-01

    In order to mitigate the negative effect of mycotoxins the major researches have been conducted to obtain the mycotoxins adsorbent in recent years. As for the adsorbents, they are substances of a firm or liquid form, on which surface the mycotoxins are absorbed and prevent transition of mycotoxins from the intestines walls in to blood system. The bentonite clay obtained in western region of Georgia (Guria, Ozurgeti) is characterized with a broad range of ion exchange, high colloidal, enriched...

  11. Efficiency of moso bamboo charcoal and activated carbon for adsorbing radioactive iodine

    Energy Technology Data Exchange (ETDEWEB)

    Chien, Chuan-Chi; Huang, Ying-Pin; Wang, Wie-Chieh [ITRI South, Industrial Technology Research Institute, Tainan (China); Chao, Jun-Hsing; Wei, Yuan-Yao [Nuclear Science and Technology Development Center, National Tsing Hua University, Hsinchu (China)

    2011-02-15

    Preventing radioactive pollution is a troublesome problem but an urgent concern worldwide because radioactive substances cause serious health-related hazards to human being. The adsorption method has been used for many years to concentrate and remove radioactive pollutants; selecting an adequate adsorbent is the key to the success of an adsorption-based pollution abatement system. In Taiwan, all nuclear power plants use activated carbon as the adsorbent to treat radiation-contaminated air emission. The activated carbon is entirely imported; its price and manufacturing technology are entirely controlled by international companies. Taiwan is rich in bamboo, which is one of the raw materials for high-quality activated carbon. Thus, a less costly activated carbon with the same or even better adsorptive capability as the imported adsorbent can be made from bamboo. The objective of this research is to confirm the adsorptive characteristics and efficiency of the activated carbon made of Taiwan native bamboo for removing {sup 131}I gas from air in the laboratory. The study was conducted using new activated carbon module assembled for treating {sup 131}I-contaminated air. The laboratory results reveal that the {sup 131}I removal efficiency for a single-pass module is as high as 70%, and the overall efficiency is 100% for four single-pass modules operated in series. The bamboo charcoal and bamboo activated carbon have suitable functional groups for adsorbing {sup 131}I and they have greater adsorption capacities than commercial activated carbons. Main mechanism is for trapping of radioiodine on impregnated charcoal, as a result of surface oxidation. When volatile radioiodine is trapped by potassium iodide-impregnated bamboo charcoal, the iodo-compound is first adsorbed on the charcoal surface, and then migrates to iodide ion sites where isotope exchange occurs. (Copyright copyright 2011 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  12. Adsorbed Organic Material and Its Control on Wettability

    DEFF Research Database (Denmark)

    Matthiesen, Jesper; Hassenkam, Tue; Bovet, Nicolas Emile

    2017-01-01

    salinity. Here we quantified the response of sandstone core plug material in its preserved state (i.e., after storage in kerosene) and after the same core plug material was treated with ethanol and ozone to remove adsorbed organic compounds. We used the chemical force microscopy (CFM) mode of atomic force...... surfaces in artificial seawater (ASW; 35,600 ppm) and in ASW diluted to ∼1,500 ppm (ASW-low). Both before and after the ethanol/ozone treatment, and for both the alkane and the carboxylate functionalized tips, the adhesion was lower in ASW diluted to ∼1,500 ppm than in ASW. For both alkane and carboxylate...... ethanol/ozone treatment, to be a result of the loss of the organic material that was originally adsorbed on these surfaces, which adds to the charge density and thereby to the salinity dependent EDL force. Investigating the same area on the same pore surface, before and after removal of the organic...

  13. XPS and bioactivity study of the bisphosphonate pamidronate adsorbed onto plasma sprayed hydroxyapatite coatings

    International Nuclear Information System (INIS)

    McLeod, Kate; Kumar, Sunil; Smart, Roger St.C.; Dutta, Naba; Voelcker, Nicolas H.; Anderson, Gail I.; Sekel, Ron

    2006-01-01

    This paper reports the use of X-ray photoelectron spectroscopy (XPS) to investigate bisphosphonate (BP) adsorption onto plasma sprayed hydroxyapatite (HA) coatings commonly used for orthopaedic implants. BPs exhibit high binding affinity for the calcium present in HA and hence can be adsorbed onto HA-coated implants to exploit their beneficial properties for improved bone growth at the implant interface. A rigorous XPS analysis of pamidronate, a commonly used nitrogenous BP, adsorbed onto plasma sprayed HA-coated cobalt-chromium substrates has been carried out, aimed at: (a) confirming the adsorption of this BP onto HA; (b) studying the BP diffusion profile in the HA coating by employing the technique of XPS depth profiling; (c) confirming the bioactivity of the adsorbed BP. XPS spectra of plasma sprayed HA-coated discs exposed to a 10 mM aqueous BP solution (pamidronate) for periods of 1, 2 and 24 h showed nitrogen and phosphorous photoelectron signals corresponding to the BP, confirming its adsorption onto the HA substrate. XPS depth profiling of the 2 h BP-exposed HA discs showed penetration of the BP into the HA matrix to depths of at least 260 nm. The bioactivity of the adsorbed BP was confirmed by the observed inhibition of osteoclast (bone resorbing) cell activity. In comparison to the HA sample, the HA sample with adsorbed BP exhibited a 25-fold decrease in primary osteoclast cells

  14. A Novel Nanohybrid Nanofibrous Adsorbent for Water Purification from Dye Pollutants.

    Science.gov (United States)

    Homaeigohar, Shahin; Zillohu, Ahnaf Usman; Abdelaziz, Ramzy; Hedayati, Mehdi Keshavarz; Elbahri, Mady

    2016-10-19

    In this study, we devised a novel nanofibrous adsorbent made of polyethersulfone (PES) for removal of methylene blue (MB) dye pollutant from water. The polymer shows a low isoelectric point thus at elevated pHs and, being nanofibrous, can offer a huge highly hydroxylated surface area for adsorption of cationic MB molecules. As an extra challenge, to augment the adsorbent's properties in terms of adsorption capacity in neutral and acidic conditions and thermal stability, vanadium pentoxide (V₂O₅) nanoparticles were added to the nanofibers. Adsorption data were analyzed according to the Freundlich adsorption model. The thermodynamic parameters verified that only at basic pH is the adsorption spontaneous and in general the process is entropy-driven and endothermic. The kinetics of the adsorption process was evaluated by the pseudo-first- and pseudo-second-order models. The latter model exhibited the highest correlation with data. In sum, the adsorbent showed a promising potential for dye removal from industrial dyeing wastewater systems, especially when envisaging their alkaline and hot conditions.

  15. Removal of adsorbent particles od copper ions by Jet flotation; Remocion de particulas adsorbentes de iones cobre por flotacion Jet

    Energy Technology Data Exchange (ETDEWEB)

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

    2009-07-01

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

  16. Application of a new adsorbent for fluoride removal from aqueous solutions

    International Nuclear Information System (INIS)

    Srivastav, Arun Lal; Singh, Prabhat K.; Srivastava, Varsha; Sharma, Yogesh C.

    2013-01-01

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

  17. Ozonation of isoproturon adsorbed on silica particles under atmospheric conditions

    Science.gov (United States)

    Pflieger, Maryline; Grgić, Irena; Kitanovski, Zoran

    2012-12-01

    The results on heterogeneous ozonation of a phenylurea pesticide, isoproturon, under atmospheric conditions are presented for the first time in the present study. The study was carried out using an experimental device previously adopted and validated for the heterogeneous reactivity of organics toward ozone (Pflieger et al., 2011). Isoproturon was adsorbed on silica particles via a liquid-to-solid equilibrium with a load far below a monolayer (0.02% by weight/surface coverage of 0.5%). The rate constants were estimated by measuring the consumption of the organic (dark, T = 26 °C, RH isoproturon on the aerosol surface does not affect the kinetics of ozonation, indicating that both compounds are adsorbed on different surface sites of silica particles.

  18. Removal of Copper(II) Ions in Aqueous Solutions Using Tannin-Rich Plants as Natural Bio-Adsorbents

    Science.gov (United States)

    Paksamut, J.; Boonsong, P.

    2018-03-01

    In this study, the purpose of our interest is to investigatethe adsorption behavior of copper (II) ions in aqueous solution using some tannin-rich plants as natural bio-adsorbents such as mangosteen peels (Garciniamangostana L.), cassava leaves (Manihotesculenta Crantz) and Thai copper pod leaves (Sennasiamea (Lam.)) as powder form in different dosage of adsorbent plant materials.The adsorption capacities at different pH of solution and contact time were performed.All the experiments in this studywere chosen at room temperature by batch technique. From the experimental results showed that cassava leaves gave better adsorbent properties than mangosteen peels and Thai copper pod leaves. The increasing dosage of all adsorbents and contact time have been found to increase adsorption capacities. In this respect, the adsorption capacities depend crucially on the adsorbents and contact time. The optimum pH of copper (II) ions adsorption was pH4. According to this work, it was observed that bioadsorbent materials from tannin-rich plants could be used to remove copper (II) ions from aqueous solutions.

  19. Decontamination of adsorbed chemical warfare agents on activated carbon using hydrogen peroxide solutions.

    Science.gov (United States)

    Osovsky, Ruth; Kaplan, Doron; Nir, Ido; Rotter, Hadar; Elisha, Shmuel; Columbus, Ishay

    2014-09-16

    Mild treatment with hydrogen peroxide solutions (3-30%) efficiently decomposes adsorbed chemical warfare agents (CWAs) on microporous activated carbons used in protective garments and air filters. Better than 95% decomposition of adsorbed sulfur mustard (HD), sarin, and VX was achieved at ambient temperatures within 1-24 h, depending on the H2O2 concentration. HD was oxidized to the nontoxic HD-sulfoxide. The nerve agents were perhydrolyzed to the respective nontoxic methylphosphonic acids. The relative rapidity of the oxidation and perhydrolysis under these conditions is attributed to the microenvironment of the micropores. Apparently, the reactions are favored due to basic sites on the carbon surface. Our findings suggest a potential environmentally friendly route for decontamination of adsorbed CWAs, using H2O2 without the need of cosolvents or activators.

  20. The reduction of oil pollutants of petroleum products storage-tanks sludge using low-cost adsorbents

    Directory of Open Access Journals (Sweden)

    Mokhtari-Hosseini Zahra Beagom

    2017-01-01

    Full Text Available Disposal of storage tank sludge in oil depots is a major environmental concern due to the high concentration of hydrocarbons involved. This paper investigates the reduction of the sludge oil pollutants with initial oil and grease concentration of about 50 mass% using low cost adsorbents. Among the examined adsorbents, sawdust indicated the maximum removal of oil and grease. The screening and optimizing of process parameters were evaluated employing Plackett-Burman design and response surface method. For the optimized conditions, more than 60 mass% of oil and grease from the sludge was removed. Moreover, it was found that sawdust adsorption of the oil and grease approximately followed the Freundlich isotherm. The results indicated that oil pollutants of sludge could be reduced using sawdust as a low-cost, available and flammable adsorbent so that thus saturated adsorbents could be used as fuel in certain industries.

  1. 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.

  2. Integrin-mediated adhesion of human mesenchymal stem cells to extracellular matrix proteins adsorbed to polymer surfaces

    International Nuclear Information System (INIS)

    Dånmark, S; Mustafa, K; Finne-Wistrand, A; Albertsson, A-C; Patarroyo, M

    2012-01-01

    In vitro, degradable aliphatic polyesters are widely used as cell carriers for bone tissue engineering, despite their lack of biological cues. Their biological active surface is rather determined by an adsorbed layer of proteins from the surrounding media. Initial cell fate, including adhesion and proliferation, which are key properties for efficient cell carriers, is determined by the adsorbed layer of proteins. Herein we have investigated the ability of human bone marrow derived stem cells (hBMSC) to adhere to extracellular matrix (ECM) proteins, including fibronectin and vitronectin which are present in plasma and serum. hBMSC expressed integrins for collagens, laminins, fibronectin and vitronectin. Accordingly, hBMSC strongly adhered to these purified ECM proteins by using the corresponding integrins. Although purified fibronectin and vitronectin adsorbed to aliphatic polyesters to a lower extent than to cell culture polystyrene, these low levels were sufficient to mediate adhesion of hBMSC. It was found that plasma- and serum-coated polystyrene adsorbed significant levels of both fibronectin and vitronectin, and fibronectin was identified as the major adhesive component of plasma for hBMSC; however, aliphatic polyesters adsorbed minimal levels of fibronectin under similar conditions resulting in impaired cell adhesion. Altogether, the results suggest that the efficiency of aliphatic polyesters cell carriers could be improved by increasing their ability to adsorb fibronectin. (paper)

  3. Interaction of atomic hydrogen with ethylene adsorbed on nickel films

    International Nuclear Information System (INIS)

    Korchak, V.N.; Tret'yakov, I.I.; Kislyuk, M.U.

    1976-01-01

    The reactivity of ethylene adsorbed on the pure films of nickel at various temperatures was studied with respect to hydrogen atoms generated in the gaseous phase. The experiments were conducted in a glass vacuum apparatus enabling one to obtain the highest vacuum up to 2x20 -10 torr. The catalyst, nickel films, was produced by their deposition onto the walls of the glass reactor at a pressure of the residual gas of 10 -9 torr and a temperature of the walls of 25 deg C. Gas purity was analyzed by the mass spectrometric method. The ethylene adsorbed at the temperatures below 173 deg K reacted readily with the hydrogen atoms to yield ethane. The process ran without practically any activation energy involved and was limited by the attachment of the first hydrogen atom to the ethylene molecule. The efficiency of this interaction was 0.02 of the number of the hydrogen atoms collisions against the surface occupied by the ethylene. The adsorption of the ethylene at room and higher temperatures was accompanied by its disproportioning with the release of the hydrogen into the gaseous phase and a serious destruction of the ethylene molecules adsorbed to produce hydrogen residues interacting with neither molecular nor atomic hydrogen [ru

  4. Ameliorating Hemorheology by Direct Hemoperfusion with a Polymyxin B-immobilized Adsorbent

    Institute of Scientific and Technical Information of China (English)

    Li Yuan; Wang Xiang; Gao Wei; Cai Shaoxi

    2004-01-01

    Direct hemoperfusion (DHP) with an adsorbent column using polymyxin B-immobilized polystyrene beads has been used to investigate the changes of hemorheology in rabbits with endotoxemia. We measured whole blood viscosity and hemotocrit before and after DHP with polymyxin B-immobilized polystyrene beads. Reduction in blood endotoxin concentration by DHP therapy positively correlated with improvement in hemorheological indexs. Our findings indicate that the amelioration in hemorheology was related directly to endotoxin removal by the adsorbent column with polymyxin B-immobilize polystyrene beads. So DHP with polymyxin B-immobilized polystyrene beads seems to be an important therapeutic strategy for endotoxemia.

  5. Natural adsorbents of dyes from aqueous solution

    Science.gov (United States)

    Rahmani, Meryem; El Hajjaji, souad; Dahchour, Abdelmalek; El M'Rabet, Mohammadine

    2017-04-01

    Contamination of natural waters is a current environmental problem and lot of work has been done to find methods for its, prevention and remediation such as ionic exchange, adsorption on active carbon, filtration, electrolysis, biodegradation …etc. Adsorption is one of the most applied methods according to its effectiveness and easy management. Some adsorbents with good properties such as active alumina, zeolites, crop residues … etc, are suitable to substitute usual active carbon. This study aimed at the removal of dyes using oil shale as natural support, and its optimization by factorial experiment. Three factors were considered namly:pollutant concentration, pH and weight of the adsorbent. Tests have been performed with cationic and anionic dyes. Experimental results show that pseudo-first-order kinetic model provided the best fit to the experimental data for the adsorption by the oil shale. Langmuir, Freundlich and Temkin isotherm models were tested to fit experimental data, the adsorption equilibrium was well described by Freundlich isotherm for methylorange and Temkin for methyl blue. Analysis were completed by oil shale characterization educing XRD, IR, XRF techniques, and cationic exchange capacity.

  6. Feasibility of using drinking water treatment residuals as a novel chlorpyrifos adsorbent.

    Science.gov (United States)

    Zhao, Yuanyuan; Wang, Changhui; Wendling, Laura A; Pei, Yuansheng

    2013-08-07

    Recent efforts have increasingly focused on the development of low-cost adsorbents for pesticide retention. In this work, the novel reuse of drinking water treatment residuals (WTRs), a nonhazardous ubiquitous byproduct, as an adsorbent for chlorpyrifos was investigated. Results showed that the kinetics and isothermal processes of chlorpyrifos sorption to WTRs were better described by a pseudo-second-order model and by the Freundlich equation, respectively. Moreover, compared with paddy soil and other documented absorbents, the WTRs exhibited a greater affinity for chlorpyrifos (log Koc = 4.76-4.90) and a higher chlorpyrifos sorption capacity (KF = 5967 mg(1-n)·L·kg(-1)) owing to the character and high content of organic matter. Further investigation demonstrated that the pH had a slight but statistically insignificant effect on chlorpyrifos sorption to WTRs; solution ionic strength and the presence of low molecular weight organic acids both resulted in concentration-dependent inhibition effects. Overall, these results confirmed the feasibility of using WTRs as a novel chlorpyrifos adsorbent.

  7. Low Pressure Adsorbent for Recovery & Storage Vented Hydrogen, Phase I

    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....

  8. Study of radiation-induced polymerization of vinyl monomers adsorbed on inorganic substances. VIII. Polymerization of styrene and methyl methacrylate adsorbed on aerosil

    International Nuclear Information System (INIS)

    Fukano, K.; Kageyama, E.

    1976-01-01

    Aerosol is silica having a purity which is very high compared with that of silica gel and having, unlike silica gel, no micropores. To investigate the effects of impurities and micropores on the radiation-induced polymerization of styrene and methyl methacrylate adsorbed on silica gel, the radiation-induced polymerization of styrene and methyl methacrylate adsorbed on Aerosil was carried out. The results of both the styrene--Aerosil 300 system and the methyl methacrylate--Aerosil 300 system were similar to those of the styrene-silica gel and methyl methacrylate-silica gel systems, respectively. This suggests that in the radiation-induced polymerization of both styrene--silica gel and methyl methacrylate--silica gel systems the impurities and the presence of micropores have almost no effect on the reaction mechanism. The effect of aluminum as an impurity was investigated on the styrene--Aerosil MOX 170 system. It was found that aluminum accelerated the cationic polymerization

  9. Single stage batch adsorber design for efficient Eosin yellow removal by polyaniline coated ligno-cellulose.

    Science.gov (United States)

    Debnath, Sushanta; Ballav, Niladri; Maity, Arjun; Pillay, Kriveshini

    2015-01-01

    Polyaniline-coated lignin-based adsorbent (PLC) was synthesized and used for uptake of reactive dye eosin yellow (EY) from aqueous solution. The adsorption capability of the adsorbent was found to be more effective than the unmodified adsorbent (LC). In particular, the adsorption capability of the PLC was effective over a wider pH range. This could be owing to its higher point of zero charge, which is more favorable for the uptake of the anionic dye. Adsorption isotherm models suggested a monolayer adsorption was predominant. The mean free energy of adsorption (E(DR)) was found to have values between 8 and 16 kJ mol(-1) which suggests that an electrostatic mechanism of adsorption predominated over other underlying mechanisms. The adsorption process was also found to be spontaneous, with increasing negative free energy values observed at higher temperatures. Chemisorption process was supported by the changes in enthalpy above 40 kJ mol(-1) and by the results of desorption studies. This new adsorbent was also reusable and regenerable over four successive adsorption-desorption cycles. The single stage adsorber design revealed that PLC can be applicable as an effective biosorbent for the treatment of industrial effluents containing EY dye. Copyright © 2014 Elsevier B.V. All rights reserved.

  10. Recovery or removal of uranium contained in small quantity in waste water by tannic-group adsorbent

    Energy Technology Data Exchange (ETDEWEB)

    Komoto, Shigetoshi [Power Reactor and Nuclear Fuel Development Corp., Kamisaibara, Okayama (Japan). Ningyo Toge Works

    1991-12-01

    It was found that tannic compounds have a very strong affinity for uranium and thorium which are nuclear fuel materials, and the new uranium adsorbents composed mainly by tannic-group compounds were made. The solid-state refractory persimmon tannins in those compounds has the most superior capacity for uranium as high as 1.7 g of uranium on 1 g of the adsorbent. The tests adsorbing uranium on the adsorbent are carried out practically by using dam water of Ningyo-toge Works, PNC. Adsorption tests changed the pH or temperature of dam water, elution test, and adsorption-elution repeating test were performed, and it was found that uranium in dam water contained from ppb-level to ppm-level was recovered or removed with very excellent efficiency. (author).

  11. Optimization of the elaboration conditions of an adsorber for the hydrogen storage; Optimisation des conditions d'elaboration d'un adsorbant pour le stockage d'hydrogene

    Energy Technology Data Exchange (ETDEWEB)

    Fierro, V.; Mareche, J.F.; Furdin, G. [Nancy-1 Univ. Henri Poincare, UMR - CNRS 7555, Laboratoire de Chimie du Solide Mineral, 54 - Vandoeuvre-les-Nancy (France); Szczurek, A.; Albiniak, A. [Wroclaw Univ. of Technology, Laboratory for Lignites and Carbon Adsorbents, Institute of Chemistry and Technology of Petroleum and Coal (Poland); Latroche, M. [Chimie Metallurgique des Terres Rares, ICMPE, UMR 7182, CNRS, 94 - Thiais (France); Celzard, A. [Nancy-Univ., ENSTIB, Laboratoire de Chimie du Solide Mineral, UMR CNRS 7555, 88 - Epinal (France)

    2008-07-01

    The microporous carbon are very efficient adsorbents for the hydrogen storage, because of pores size under 2 nm. This study describes the optimization of the elaboration conditions for a carbon adsorbent for the hydrogen storage by adsorption. The storage capacity has been measured at 25 C for 20 MPa and also at 77 K for pressures between 6 and 9 MPa. the porous texture characterization has been realized by four molecule probes of increasing diameter: CO{sub 2}, N{sub 2}, C{sub 6}H{sub 6} and CCl{sub 4}. (A.L.B.)

  12. Iodine-adsorbent poisoning: FY-82 summary report

    International Nuclear Information System (INIS)

    Jolley, J.G.; Casper, L.A.

    1982-10-01

    Along with its positive attributes as an adsorbent of radioiodine in nuclear plant air cleaning systems, silver zeolite has the disadvantage of being susceptible to poisoning. (Poisoning is defined as the reduction of efficiency in radioiodine removal.) In view of the gravimetric and infrared spectroscopy data presented, π-bonded hydrocarbons, oxygenated organics, and halocarbons appear to be probable poisons of a silver zeolite filtration system

  13. Development of a new adsorbent from agro-industrial waste and its potential use in endocrine disruptor compound removal

    International Nuclear Information System (INIS)

    Rovani, Suzimara; Censi, Monique T.; Pedrotti, Sidnei L.; Lima, Éder C.; Cataluña, Renato; Fernandes, Andreia N.

    2014-01-01

    Highlights: • Development of a new adsorbent from agro-industrial waste. • Characterization by chemical and spectroscopic methods. • Alternative for the treatment of effluents that contain estrogens. • The AC adsorbent was successfully employed as solid phase adsorbent for the preconcentration of E2 and EE2 from aqueous solutions. - Abstract: A new activated carbon (AC) material was prepared by pyrolysis of a mixture of coffee grounds, eucalyptus sawdust, calcium hydroxide and soybean oil at 800 °C. This material was used as adsorbent for the removal of the endocrine disruptor compounds 17β-estradiol (E2) and 17α-ethinylestradiol (EE2) from aqueous solutions. The carbon material was characterized by scanning electron microscopy (SEM), infrared spectroscopy (FTIR), N 2 adsorption/desorption curves and point of zero charge (pH PZC ). Variables including the initial pH of the adsorbate solutions, adsorbent masses and contact time were optimized. The optimum range of initial pH for removal of endocrine disruptor compounds (EDC) was 2.0–11.0. The kinetics of adsorption were investigated using general order, pseudo first-order and pseudo-second order kinetic models. The Sips isotherm model gave the best fits of the equilibrium data (298 K). The maximum amounts of E2 and EE2 removed at 298 K were 7.584 (E2) and 7.883 mg g −1 (EE2) using the AC as adsorbent. The carbon adsorbent was employed in SPE (solid phase extraction) of E2 and EE2 from aqueous solutions

  14. Development of a new adsorbent from agro-industrial waste and its potential use in endocrine disruptor compound removal

    Energy Technology Data Exchange (ETDEWEB)

    Rovani, Suzimara; Censi, Monique T.; Pedrotti, Sidnei L.; Lima, Éder C.; Cataluña, Renato; Fernandes, Andreia N., E-mail: andreia.fernandes@ufrgs.br

    2014-04-01

    Highlights: • Development of a new adsorbent from agro-industrial waste. • Characterization by chemical and spectroscopic methods. • Alternative for the treatment of effluents that contain estrogens. • The AC adsorbent was successfully employed as solid phase adsorbent for the preconcentration of E2 and EE2 from aqueous solutions. - Abstract: A new activated carbon (AC) material was prepared by pyrolysis of a mixture of coffee grounds, eucalyptus sawdust, calcium hydroxide and soybean oil at 800 °C. This material was used as adsorbent for the removal of the endocrine disruptor compounds 17β-estradiol (E2) and 17α-ethinylestradiol (EE2) from aqueous solutions. The carbon material was characterized by scanning electron microscopy (SEM), infrared spectroscopy (FTIR), N{sub 2} adsorption/desorption curves and point of zero charge (pH{sub PZC}). Variables including the initial pH of the adsorbate solutions, adsorbent masses and contact time were optimized. The optimum range of initial pH for removal of endocrine disruptor compounds (EDC) was 2.0–11.0. The kinetics of adsorption were investigated using general order, pseudo first-order and pseudo-second order kinetic models. The Sips isotherm model gave the best fits of the equilibrium data (298 K). The maximum amounts of E2 and EE2 removed at 298 K were 7.584 (E2) and 7.883 mg g{sup −1} (EE2) using the AC as adsorbent. The carbon adsorbent was employed in SPE (solid phase extraction) of E2 and EE2 from aqueous solutions.

  15. [Ability of typical greenery shrubs of Beijing to adsorb and arrest PM2.5 ].

    Science.gov (United States)

    Liang, Dan; Wang, Bin; Wang, Yun-qi; Zhang, Hui-lan; Yang, Song-nan; Li, Ang

    2014-09-01

    Four typical types of green shrubs of Beijing (Euonymus japonicus, Buxus microphylla, Berberis thunbergii cv. atropurpurea, Taxus cuspidate cv. nana) were selected to study their capacities in adsorbing and arresting PM2.5 using both field observations and air chamber simulations. Concurrently, in order to analyze the pollution characteristics of Beijing in winter and spring, the PM2.5 concentrations of December 2012 to May 2013 were collected. Experimental results showed that: From the gas chamber experiments, the ability to adsorb and arrest PM2.5 was in the order of Berberis thunbergii cv. atropurpurea > Buxus microphylla > Taxus cuspidate cv. nana > Euonymus japonicus, mainly due to the differences in leaf characteristics; Outside measurement results showed that the ability to adsorb and arrest PM2.5 was ranked as Buxus microphylla > Berberis thunbergii cv. atropurpurea > Taxus cuspidate cv. nana > Euonymus japonicus. Chamber simulation and outdoor observation showed that Buxus microphylla and Berberis thunbergii cv. atropurpurea had strong ability to adsorb and arrest PM2.5; Meanwhile, the slight differences between the chamber simulation and outdoor observation results might be related to plant structure. Compared to tree species, the planting condition of shrub species was loose, and it greened quickly; By analyzing the Beijing PM2.5 concentration values in winter and spring, it was found that the PM2.5 concentration was particularly high in the winter of Beijing, and evergreen shrubs maintained the ability to adsorb and arrest PM2.5.

  16. Removal of uranium from aqueous solution by a low cost and high-efficient adsorbent

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Yun-Hai [State Key Laboratory Breeding Base of Nuclear Resources and Environment (East China Institute of Technology), Ministry of Education, Nanchang, 330013 (China); Key Laboratory of Radioactive Geology and Exploration Technology Fundamental Science for National Defense, East China Institute of Technology, Fuzhou, 344000 (China); Chemistry, Biological and Materials Sciences Department, East China Institute of Technology, Fuzhou, 344000 (China); Wang, You-Qun [Key Laboratory of Radioactive Geology and Exploration Technology Fundamental Science for National Defense, East China Institute of Technology, Fuzhou, 344000 (China); Chemistry, Biological and Materials Sciences Department, East China Institute of Technology, Fuzhou, 344000 (China); Zhang, Zhi-Bin, E-mail: zhangnjut@163.com [State Key Laboratory Breeding Base of Nuclear Resources and Environment (East China Institute of Technology), Ministry of Education, Nanchang, 330013 (China); Key Laboratory of Radioactive Geology and Exploration Technology Fundamental Science for National Defense, East China Institute of Technology, Fuzhou, 344000 (China); Chemistry, Biological and Materials Sciences Department, East China Institute of Technology, Fuzhou, 344000 (China); Cao, Xiao-Hong; Nie, Wen-Bin; Li, Qin [Key Laboratory of Radioactive Geology and Exploration Technology Fundamental Science for National Defense, East China Institute of Technology, Fuzhou, 344000 (China); Chemistry, Biological and Materials Sciences Department, East China Institute of Technology, Fuzhou, 344000 (China); Hua, Rong [State Key Laboratory Breeding Base of Nuclear Resources and Environment (East China Institute of Technology), Ministry of Education, Nanchang, 330013 (China); Key Laboratory of Radioactive Geology and Exploration Technology Fundamental Science for National Defense, East China Institute of Technology, Fuzhou, 344000 (China); Chemistry, Biological and Materials Sciences Department, East China Institute of Technology, Fuzhou, 344000 (China)

    2013-05-15

    In this study, a low-cost and high-efficient carbonaceous adsorbent (HTC-COOH) with carboxylic groups was developed for U(VI) removal from aqueous solution compared with the pristine hydrothermal carbon (HTC). The structure and chemical properties of resultant adsorbents were characterized by Scanning electron microscope (SEM), N{sub 2} adsorption–desorption, Fourier transform-infrared spectra (FT-IR) and acid–base titration. The key factors (solution pH, contact time, initial U(VI) concentrations and temperature) affected the adsorption of U(VI) on adsorbents were investigated using batch experiments. The adsorption of U(VI) on HTC and HTC-COOH was pH-dependent, and increased with temperature and initial ion concentration. The adsorption equilibrium of U(VI) on adsorbents was well defined by the Langmuir isothermal equation, and the monolayer adsorption capacity of HTC-COOH was found to be 205.8 mg/g. The kinetics of adsorption was very in accordance with the pseudo-second-order rate model. The adsorption processes of U(VI) on HTC and HTC-COOH were endothermic and spontaneous in nature according to the thermodynamics of adsorption. Furthermore, HTC-COOH could selectively adsorption of U(VI) in aqueous solution containing co-existing ions (Mg{sup 2+}, Co{sup 2+}, Ni{sup 2+}, Zn{sup 2+} and Mn{sup 2+}). From the results of the experiments, it is found that the HTC-COOH is a potential adsorbent for effective removal of U(VI) from polluted water.

  17. Removal of uranium from aqueous solution by a low cost and high-efficient adsorbent

    Science.gov (United States)

    Liu, Yun-Hai; Wang, You-Qun; Zhang, Zhi-Bin; Cao, Xiao-Hong; Nie, Wen-Bin; Li, Qin; Hua, Rong

    2013-05-01

    In this study, a low-cost and high-efficient carbonaceous adsorbent (HTC-COOH) with carboxylic groups was developed for U(VI) removal from aqueous solution compared with the pristine hydrothermal carbon (HTC). The structure and chemical properties of resultant adsorbents were characterized by Scanning electron microscope (SEM), N2 adsorption-desorption, Fourier transform-infrared spectra (FT-IR) and acid-base titration. The key factors (solution pH, contact time, initial U(VI) concentrations and temperature) affected the adsorption of U(VI) on adsorbents were investigated using batch experiments. The adsorption of U(VI) on HTC and HTC-COOH was pH-dependent, and increased with temperature and initial ion concentration. The adsorption equilibrium of U(VI) on adsorbents was well defined by the Langmuir isothermal equation, and the monolayer adsorption capacity of HTC-COOH was found to be 205.8 mg/g. The kinetics of adsorption was very in accordance with the pseudo-second-order rate model. The adsorption processes of U(VI) on HTC and HTC-COOH were endothermic and spontaneous in nature according to the thermodynamics of adsorption. Furthermore, HTC-COOH could selectively adsorption of U(VI) in aqueous solution containing co-existing ions (Mg2+, Co2+, Ni2+, Zn2+ and Mn2+). From the results of the experiments, it is found that the HTC-COOH is a potential adsorbent for effective removal of U(VI) from polluted water.

  18. Enhancement of mass transfer by ultrasound: Application to adsorbent regeneration and food drying/dehydration.

    Science.gov (United States)

    Yao, Ye

    2016-07-01

    The physical mechanisms of heat and mass transfer enhancement by ultrasound have been identified by people. Basically, the effect of 'cavitation' induced by ultrasound is the main reason for the enhancement of heat and mass transfer in a liquid environment, and the acoustic streaming and vibration are the main reasons for that in a gaseous environment. The adsorbent regeneration and food drying/dehydration are typical heat and mass transfer process, and the intensification of the two processes by ultrasound is of complete feasibility. This paper makes an overview on recent studies regarding applications of power ultrasound to adsorbent regeneration and food drying/dehydration. The concerned adsorbents include desiccant materials (typically like silica gel) for air dehumidification and other ones (typically active carbon and polymeric resin) for water treatment. The applications of ultrasound in the regeneration of these adsorbents have been proved to be energy saving. The concerned foods are mostly fruits and vegetables. Although the ultrasonic treatment may cause food degradation or nutrient loss, it can greatly reduce the food processing time and decrease drying temperature. From the literature, it can be seen that the ultrasonic conditions (i.e., acoustic frequency and power levels) are always focused on during the study of ultrasonic applications. The increasing number of relevant studies argues that ultrasound is a very promising technology applied to the adsorbent regeneration and food drying/dehydration. Copyright © 2016 Elsevier B.V. All rights reserved.

  19. 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.

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

    KAUST Repository

    Sueyoshi, Mark; Al-Maamari, Rashid S.; Jibril, Baba Y.; Tasaki, Masaharu; Okamura, Kazuo; Kuwagaki, Hitoshi; Yahiro, Hidenori; Sagata, Kunimasa; Han, Yu

    2012-01-01

    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.

  1. Evaluation of optimal silver amount for the removal of methyl iodide on silver-impregnated adsorbents

    International Nuclear Information System (INIS)

    Park, G.I.; Cho, I.H.; Kim, J.H.; Oh, W.Z.

    2001-01-01

    The adsorption characteristics of methyl iodide generated from the simulated off-gas stream on various adsorbents such as silver-impregnated zeolite (AgX), zeocarbon and activated carbon were investigated. An extensive evaluation was made on the optimal silver impregnation amount for the removal of methyl iodide at temperatures up to 300 deg. C. The degree of adsorption efficiency of methyl iodide on silver-impregnated adsorbent is strongly dependent on impregnation amount and process temperature. A quantitative comparison of adsorption efficiencies on three adsorbents in a fixed bed was investigated. The influence of temperature, methyl iodide concentration and silver impregnation amount on the adsorption efficiency is closely related to the pore characteristics of adsorbents. It shows that the effective impregnation ratio was about 10wt%, based on the degree of silver utilization for the removal of methyl iodide. The practical applicability of silver-impregnated zeolite for the removal of radioiodine generated from the DUPIC process was consequently proposed. (author)

  2. A new alternative adsorbent for the removal of cationic dyes from aqueous solution

    Directory of Open Access Journals (Sweden)

    T. Santhi

    2016-09-01

    Full Text Available Adsorption of Malachite green (MG and Methylene blue (MB from aqueous solutions on low cost adsorbent prepared from Annona squmosa seed (CAS is studied experimentally. Results obtained indicate that the removal efficiency of Malachite green and Methylene blue at 27 ± 2 °C exceeds 75.66% and 24.33% respectively, and that the adsorption process is highly pH-dependent. Results showed that the optimum pH for dye removal is 6.0. The amount of dye adsorbed from aqueous solution increases with the increase of the initial dye concentration. Smaller adsorbent particle adds to increase the percentage removal of Malachite green and Methylene blue. The equilibrium data fitted well to the Langmuir model (R2 > 0.97 and the adsorption kinetic followed the pseudo-second-order equation (R2 > 0.99. The maximum adsorption capacities of MG, MB on CAS are 25.91 mg g−1 and 08.52 mg g−1 respectively. These results suggest that A. squmosa seed is a potential low-cost adsorbent for the dye removal from industrial wastewater. The adsorption capacity of CAS on MG is greater than MB.

  3. Competitive Adsorption of Metals onto Magnetic Graphene Oxide: Comparison with Other Carbonaceous Adsorbents

    Directory of Open Access Journals (Sweden)

    Jin Hur

    2015-01-01

    Full Text Available Competitive adsorption isotherms of Cu(II, Pb(II, and Cd(II were examined on a magnetic graphene oxide (GO, multiwalled carbon nanotubes (MWCNTs, and powered activated carbon (PAC. A series of analyses confirmed the successful synthesis of the magnetic GO based on a simple ultrasonification method. Irrespective of the adsorbents, the adsorption was highly dependent on pH, and the adsorption was well described by the Langmuir isotherm model. The maximum adsorption capacities of the adsorbents were generally higher in the order of Pb(II > Cu(II > Cd(II, which is the same as the degree of the electronegativity and the hydrated radius of the metals, suggesting that the metal adsorption may be governed by an ion exchange between positively charged metals and negatively charged surfaces, as well as diffusion of metals into the surface layer. The adsorption of each metal was mostly lower for multi- versus single-metal systems. The antagonistic effects were influenced by solution pH as well as the type of metals, and they were higher in the order of the magnetic GO > MWCNT > PAC. Dissolved HS played a greater role than HS adsorbed onto the adsorbents, competing with the adsorption sites for metal complexation.

  4. Solid waste from leather industry as adsorbent of organic dyes in aqueous-medium

    International Nuclear Information System (INIS)

    Oliveira, Luiz C.A.; Goncalves, Maraisa; Oliveira, Diana Q.L.; Guerreiro, Mario C.; Guilherme, Luiz R.G.; Dallago, Rogerio M.

    2007-01-01

    The industrial tanning of leather usually produces considerable amounts of chromium-containing solid waste and liquid effluents and raises many concerns on its environmental effect as well as on escalating landfill costs. Actually, these shortcomings are becoming increasingly a limiting factor to this industrial activity that claims for alternative methods of residue disposals. In this work, it is proposed a novel alternative destination of the solid waste, based on the removal of organic contaminants from the out coming aqueous-residue. The adsorption isotherm pattern for the wet blue leather from the Aurea tanning industry in Erechim-RS (Brazil) showed that these materials present high activity on adsorbing the reactive red textile dye as well as other compounds. The adsorbent materials were characterized by IR spectroscopy and SEM and tested for the dye adsorption (reactive textile and methylene blue dyes). The concentrations of dyes were measured by UV-vis spectrophotometry and the chromium extraction from leather waste was realized by basic hydrolysis and determined by atomic absorption. As a low cost abundant adsorbent material with high adsorption ability on removing dye methylene blue (80 mg g -1 ) and textile dye reactive red (163 mg g -1 ), the leather waste is revealed to be a interesting alternative relatively to more costly adsorbent materials

  5. Solid waste from leather industry as adsorbent of organic dyes in aqueous-medium

    Energy Technology Data Exchange (ETDEWEB)

    Oliveira, Luiz C.A. [Universidade Federal de Lavras, Depto. de Quimica, Caixa Postal 37, CEP 37200.000, Lavras-MG (Brazil)]. E-mail: luizoliveira@ufla.br; Goncalves, Maraisa [Universidade Federal de Lavras, Depto. de Quimica, Caixa Postal 37, CEP 37200.000, Lavras-MG (Brazil); Oliveira, Diana Q.L. [Universidade Federal de Lavras, Depto. de Quimica, Caixa Postal 37, CEP 37200.000, Lavras-MG (Brazil); Guerreiro, Mario C. [Universidade Federal de Lavras, Depto. de Quimica, Caixa Postal 37, CEP 37200.000, Lavras-MG (Brazil); Guilherme, Luiz R.G. [Universidade Federal de Lavras, Depto. de Ciencia do solo, CEP 37200.000, Lavras-MG (Brazil); Dallago, Rogerio M. [URI-Campus Erechim, Av. 7 Setembro 1621, Centro, CEP 99700-000, Depto de Quimica, Erechim-RS (Brazil)

    2007-03-06

    The industrial tanning of leather usually produces considerable amounts of chromium-containing solid waste and liquid effluents and raises many concerns on its environmental effect as well as on escalating landfill costs. Actually, these shortcomings are becoming increasingly a limiting factor to this industrial activity that claims for alternative methods of residue disposals. In this work, it is proposed a novel alternative destination of the solid waste, based on the removal of organic contaminants from the out coming aqueous-residue. The adsorption isotherm pattern for the wet blue leather from the Aurea tanning industry in Erechim-RS (Brazil) showed that these materials present high activity on adsorbing the reactive red textile dye as well as other compounds. The adsorbent materials were characterized by IR spectroscopy and SEM and tested for the dye adsorption (reactive textile and methylene blue dyes). The concentrations of dyes were measured by UV-vis spectrophotometry and the chromium extraction from leather waste was realized by basic hydrolysis and determined by atomic absorption. As a low cost abundant adsorbent material with high adsorption ability on removing dye methylene blue (80 mg g{sup -1}) and textile dye reactive red (163 mg g{sup -1}), the leather waste is revealed to be a interesting alternative relatively to more costly adsorbent materials.

  6. Innovative Elution Processes for Recovering Uranium and Transition Metals from Amidoxime-based Adsorbents

    Energy Technology Data Exchange (ETDEWEB)

    Wai, Chien M. [Univ. of Idaho, Moscow, ID (United States). Dept. of Chemistry

    2017-04-18

    Amidoxime-based polymer fibers are considered one of the most promising materials for sequestering uranium from seawater. The high-surface-area polymer fibers containing amidoxime and carboxylate groups synthesized by Oak Ridge National Lab (ORNL-AF1) show very high uranium adsorption capacities known in the literature. Effective elution of uranium and repeated use of the adsorbent are important factors affecting the cost of producing uranium from seawater using this material. Traditional acid leaching of uranium followed by KOH conditioning of the fiber causes chemical changes and physical damage to the ORNL-AF1 adsorbent. Two alkaline solution leaching methods were developed by this project, one uses a highly concentrated (3 M) potassium bicarbonate solution at pH 8.3 and 40 °C; the other uses a mixture of sodium carbonate and hydrogen peroxide at pH 10.4. Both elution methods do not require KOH conditioning prior to reusing the fiber adsorbent. The conditions of eluting uranium from the amidoxime-based adsorbent using these alkaline solutions are confirmed by thermodynamic calculations. The bicarbonate elution method is selective for uranium recovery compared to other elution methods and causes no chemical change to the fiber material based on FTIR spectroscopy

  7. Sacrificial adsorbate for surfactants utilized in chemical floods of enhanced oil recovery operations

    Science.gov (United States)

    Johnson, Jr., James S.; Westmoreland, Clyde G.

    1982-01-01

    The present invention is directed to a sacrificial or competitive adsorbate for surfactants contained in chemical flooding emulsions for enhanced oil recovery operations. The adsorbate to be utilized in the method of the present invention is a caustic effluent from the bleach stage or the weak black liquor from the digesters and pulp washers of the kraft pulping process. This effluent or weak black liquor is injected into an oil-bearing subterranean earth formation prior to or concurrent with the chemical flood emulsion and is adsorbed on the active mineral surfaces of the formation matrix so as to effectively reduce adsorption of surfactant in the chemical flood. Alternatively, the effluent or liquor can be injected into the subterranean earth formation subsequent to a chemical flood to displace the surfactant from the mineral surfaces for the recovery thereof.

  8. New Fiber Materials with Sorption Capacity at 5.0 g-U/kg Adsorbent under Marine Testing Conditions

    Energy Technology Data Exchange (ETDEWEB)

    Saito, Tomonori [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Brown, S. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Das, Sadananda [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); Kuo, Li-Jung [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Strivens, Jonathan E. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Schlafer, Nicholas [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Wood, J. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Gill, G. A. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Flicker Byers, M. [Univ. of Texas, Austin, TX (United States); Schneider, Eric [Univ. of Texas, Austin, TX (United States)

    2016-03-30

    The Fuel Resources program of the Fuel Cycle Research and Development program of the Office of Nuclear Energy (NE) has focused on assuring that nuclear fuel resources are available in the United States for a long term. An immense source of uranium is seawater, which contains an estimated amount of 4.5 billion tonnes of dissolved uranium. Extraction of the uranium resource in seawater 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 make the seawater uranium recovery technology a cost competitive, viable technology. Under this program, Oak Ridge National Laboratory (ORNL) has developed several novel adsorbents, which enhanced the uranium capacity 4-5 times from the state-of-the art Japanese adsorbents. Uranium exists uniformly at a concentration of ~3.3 ppb in seawater. Because of the vast volume of the oceans, the total estimated amount of uranium in seawater is approximately 1000 times larger than its amount in terrestrial resources. However, due to the low concentration, a significant challenge remains for making the extraction of uranium from seawater a commercially viable alternative technology. The biggest challenge for this technology to overcome to efficiently reduce the extraction cost is to develop adsorbents with increased uranium adsorption capacity. Two major approaches were investigated for synthesizing novel adsorbents with enhanced uranium adsorption capacity. One method utilized conventional radiation induced graft polymerization (RIGP) to synthesize adsorbents on high-surface area trunk fibers and the other method utilized a chemical grafting technique, atom-transfer radical polymerization (ATRP). Both approaches have shown promising uranium extraction

  9. Adsorbed polymers in aqueous media. The relation between zeta-potential, layer thickness and ionic strength

    NARCIS (Netherlands)

    Cohen Stuart, M.A.; Mulder, J.W.

    1985-01-01

    Streaming potentials for glass capillaries with and without adsorbed poly(vinyl pyrrolidone) were used to determine the thickness of the adsorbed polymer layer. It was found that the thickness determined in this way is a strong function of the ionic strength of the solution. The results are compared

  10. La2O3 turinčių CO2 adsorbentų savybės ir taikymas

    OpenAIRE

    Ziutelis, Tomas

    2015-01-01

    In Master`s thesis "Properties and application of La2O3-containing CO2 adsorbents" adsorption properties of La2O3-containing carbon dioxide adsorbents were studied. Interaction between carbon dioxide and lanthanum oxide was evaluated. Equilibrium and kinetic parameters of experimental process were calculated. Based on the results of experiment the possibility of application of lanthanum oxide containing adsorbents for concentration of carbon dioxide from compressed air were evaluated.

  11. Contribution of Adsorbed Protein Films to Nanoscopic Vibrations Exhibited by Bacteria Adhering through Ligand-Receptor Bonds.

    Science.gov (United States)

    Song, Lei; Sjollema, Jelmer; Norde, Willem; Busscher, Henk J; van der Mei, Henny C

    2015-09-29

    Bacteria adhering to surfaces exhibit nanoscopic vibrations that depend on the viscoelasticity of the bond. The quantification of the nanoscopic vibrations of bacteria adhering to surfaces provides new opportunities to better understand the properties of the bond through which bacteria adhere and the mechanisms by which they resist detachment. Often, however, bacteria do not adhere to bare surfaces but to adsorbed protein films, on which adhesion involves highly specific ligand-receptor binding next to nonspecific DLVO interaction forces. Here we determine the contribution of adsorbed salivary protein and fibronectin films to vibrations exhibited by adhering streptococci and staphylococci, respectively. The streptococcal strain used has the ability to adhere to adsorbed salivary proteins films through antigen I/II ligand-receptor binding, while the staphylococcal strain used adheres to adsorbed fibronectin films through a proteinaceous ligand-receptor bond. In the absence of ligand-receptor binding, electrostatic interactions had a large impact on vibration amplitudes of adhering bacteria on glass. On an adsorbed salivary protein film, vibration amplitudes of adhering streptococci depended on the film softness as determined by QCM-D and were reduced after film fixation using glutaraldehyde. On a relatively stiff fibronectin film, cross-linking the film in glutaraldehyde hardly reduced its softness, and accordingly fibronectin film softness did not contribute to vibration amplitudes of adhering staphylococci. However, fixation of the staphylococcus-fibronectin bond further decreased vibration amplitudes, while fixation of the streptococcus bond hardly impacted vibration amplitudes. Summarizing, this study shows that both the softness of adsorbed protein films and the properties of the bond between an adhering bacterium and an adsorbed protein film play an important role in bacterial vibration amplitudes. These nanoscopic vibrations reflect the viscoelasticity of the

  12. Molecular analysis of petroleum derived compounds that adsorb onto gas hydrate surfaces

    International Nuclear Information System (INIS)

    Borgund, Anna E.; Hoiland, Sylvi; Barth, Tanja; Fotland, Per; Askvik, Kjell M.

    2009-01-01

    Field observations have shown that some streams of water, gas and crude oil do not form gas hydrate plugs during petroleum production even when operating within thermodynamic conditions for hydrate formation. Also, when studied under controlled laboratory conditions, some oils are found to form hydrate dispersed systems whereas others form plugs. Oils with low tendency to form hydrate plugs are believed to contain natural hydrate plug inhibiting components (NICs) that adsorb onto the hydrate surface, making them less water-wet and preventing the particles from agglomerating into large hydrate clusters. The molecular structure of the NICs is currently unknown. In this work, hydrate adsorbing components were extracted from crude oils using freon hydrates as an extraction phase. The fractions were found to be enriched in polar material, and more polar material is associated with hydrates generated in biodegraded crude oils than in non-biodegraded oils. Various fractionation schemes and analytical techniques have been applied in the search for molecular characterisation. The average molecular weights were found to be approximately 500 g/mole. GC-MS chromatograms show a large UCM (Unresolved Complex Mixture). Thus, GC-MS has a limited potential for identification of compounds. A commercial biosurfactant was used as a model compound in the search for similar structures in the extracts. The results from analysis of the hydrate adsorbing components suggest that the type and structure are more important for hydrate morphology than the amount of material adsorbed.

  13. Adsorbate-induced modification of electronic band structure of epitaxial Bi(111) films

    Energy Technology Data Exchange (ETDEWEB)

    Matetskiy, A.V., E-mail: mateckij@iacp.dvo.ru [Institute of Automation and Control Processes FEB RAS, 5 Radio Street, 690041 Vladivostok (Russian Federation); Bondarenko, L.V.; Tupchaya, A.Y.; Gruznev, D.V. [Institute of Automation and Control Processes FEB RAS, 5 Radio Street, 690041 Vladivostok (Russian Federation); Eremeev, S.V. [Institute of Strength Physics and Materials Science, 634021 Tomsk (Russian Federation); Tomsk State University, 634050 Tomsk (Russian Federation); Zotov, A.V. [Institute of Automation and Control Processes FEB RAS, 5 Radio Street, 690041 Vladivostok (Russian Federation); School of Natural Sciences, Far Eastern Federal University, 690950 Vladivostok (Russian Federation); Department of Electronics, Vladivostok State University of Economics and Service, 690600 Vladivostok (Russian Federation); Saranin, A.A. [Institute of Automation and Control Processes FEB RAS, 5 Radio Street, 690041 Vladivostok (Russian Federation); School of Natural Sciences, Far Eastern Federal University, 690950 Vladivostok (Russian Federation)

    2017-06-01

    Highlights: • Modification of electronic properties of ultrathin Bi films by adsorbates is demonstrated. • Due to electron doping from Cs adatoms, surface-state bands shift to higher binding energies. • As a result, only electron pockets are left in the Fermi map. • Tin acts as an acceptor dopant for Bi, shifting Fermi level upward. • As a result, only hole pockets are left in the Fermi map. - Abstract: Changes of the electronic band structure of Bi(111) films on Si(111) induced by Cs and Sn adsorption have been studied using angle-resolved photoemission spectroscopy and density functional theory calculations. It has been found that small amounts of Cs when it presents at the surface in a form of the adatom gas leads to shifting of the surface and quantum well states to the higher binding energies due to the electron donation from adsorbate to the Bi film. In contrast, adsorbed Sn dissolves into the Bi film bulk upon heating and acts as an acceptor dopant, that results in shifting of the surface and quantum well states upward to the lower binding energies. These results pave the way to manipulate with the Bi thin film electron band structure allowing to achieve a certain type of conductivity (electron or hole) with a single spin channel at the Fermi level making the adsorbate-modified Bi a reliable base for prospective spintronics applications.

  14. Disinfection of water with new chitosan-modified hybrid clay composite adsorbent

    Directory of Open Access Journals (Sweden)

    Emmanuel I. Unuabonah

    2017-08-01

    Full Text Available Hybrid clay composites were prepared from Kaolinite clay and Carica papaya seeds via modification with chitosan, Alum, NaOH, and ZnCl2 in different ratios, using solvothermal and surface modification techniques. Several composite adsorbents were prepared, and the most efficient of them for the removal of gram negative enteric bacteria was the hybrid clay composite that was surface-modified with chitosan, Ch-nHYCA1:5 (Chitosan: nHYCA = 1:5. This composite adsorbent had a maximum adsorption removal value of 4.07 × 106 cfu/mL for V. cholerae after 120 min, 1.95 × 106 cfu/mL for E. coli after ∼180 min and 3.25 × 106 cfu/mL for S. typhi after 270 min. The Brouers-Sotolongo model was found to better predict the maximum adsorption capacity (qmax of Ch-nHYCA1:5 composite adsorbent for the removal of E. coli with a qmax of 103.07 mg/g (7.93 × 107 cfu/mL and V. cholerae with a qmax of 154.18 mg/g (1.19 × 108 cfu/mL while the Sips model best described S. typhi adsorption by Ch-nHYCA1:5 composite with an estimated qmax of 83.65 mg/g (6.43 × 107 cfu/mL. These efficiencies do far exceed the alert/action levels of ca. 500 cfu/mL in drinking water for these bacteria. The simplicity of the composite preparation process and the availability of raw materials used for its preparation underscore the potential of this low-cost chitosan-modified composite adsorbent (Ch-nHYCA1:5 for water treatment.

  15. Structure and chemical composition of layers adsorbed at interfaces with champagne.

    Science.gov (United States)

    Aguié-Béghin, V; Adriaensen, Y; Péron, N; Valade, M; Rouxhet, P; Douillard, R

    2009-11-11

    The structure and the chemical composition of the layer adsorbed at interfaces involving champagne have been investigated using native champagne, as well as ultrafiltrate (UFch) and ultraconcentrate (UCch) obtained by ultrafiltration with a 10(4) nominal molar mass cutoff. The layer adsorbed at the air/liquid interface was examined by surface tension and ellipsometry kinetic measurements. Brewster angle microscopy demonstrated that the layer formed on polystyrene by adsorption or drop evaporation was heterogeneous, with a domain structure presenting similarities with the layer adsorbed at the air/liquid interface. The surface chemical composition of polystyrene with the adlayer was determined by X-ray photoelectron spectroscopy (XPS). The contribution of champagne constituents varied according to the liquid (native, UFch, and UCch) and to the procedure of adlayer formation (evaporation, adsorption, and adsorption + rinsing). However, their chemical composition was not significantly influenced either by ultrafiltration or by the procedure of deposition on polystyrene. Modeling this composition in terms of classes of model compounds gave approximately 35% (w/w) of proteins and 65% (w/w) of polysaccharides. In the adlayer, the carboxyl groups or esters represent about 18% of carbon due to nonpolypeptidic compounds, indicating the presence of either uronic acids in the complex structure of pectic polysaccharides or of polyphenolic esters. This structural and chemical information and its relationship with the experimental procedures indicate that proteins alone cannot be used as a realistic model for the macromolecules forming the adsorption layer of champagne. Polysaccharides, the other major macromolecular components of champagne wine, are assembled with proteins at the interfaces, in agreement with the heterogeneous character of the adsorbed layer at interfaces.

  16. Comparison of Analytical and Numerical Model of Adsorber/desorber of Silica Gel-Water Adsorption Heat Pump

    Directory of Open Access Journals (Sweden)

    Katarzyna Zwarycz-Makles

    2017-03-01

    Full Text Available In the paper comparison of an analytical and a numerical model of silica gel/water adsorber/desorber was presented. Adsorber/desorber as a part of the two–bed single–stage adsorption heat pump was discussed. The adsorption heat pump under consideration consists of an evaporator, two adsorber/desorber columns and a condenser. During operation of assumed adsorption heat pump only heat and mass transfer was taken into account. The both presented mathematical models were created to describe the temperature, heat and concentration changes in the adsorber/desorber and consequently to describe the performance of the adsorption heat pump. Adsorption equilibrium was described by the Dubinin-Astachov model. Adsorption and desorption process dynamics was described by application of the linear driving force model (LDF. In the analysis temperatures of evaporation and condensation were constant.

  17. Electron-Stimulated Desorption of Positive Ions from Methanol Adsorbed on a Solid Ar Substrate

    Science.gov (United States)

    Kawanowa, H.; Hanatani, K.; Gotoh, Y.; Souda, R.

    Electron-stimulated desorption (ESD) of positive ions from weakly physisorbed molecules has been investigated. From methanol adsorbed on a solid Ar substrate, the protonated cluster ions of the type H+(CH3OH)n (n = 1 - 4) are emitted, together with the fragment ions such as CHn+ (n = 0 - 3), H3O+, CHO+, CH3O+, etc. The yields of these ions are markedly enhanced at the smallest coverage and decay steeply with increasing coverage. Coulomb explosion between valence holes confined in adsorbed nanoclusters is responsible for the enhanced ion yields. Very few ions except for H+ are emitted from a thick layer as well as nanoclusters adsorbed directly on a metal substrate due to the delocalization of valence holes.

  18. Fundamental adsorption characteristics of carbonaceous adsorbents for 1,2,3,4-tetrachlorobenzene in a model gas of an incineration plant.

    Science.gov (United States)

    Inoue, Kenichiro; Kawamoto, Katsuya

    2005-08-01

    Carbonaceous adsorbents such as activated carbon have been used to reduce the emission of organic pollutants from incineration plants. However, with this method, the amount and type of adsorbent to be used are based only on empirical results, which may lead to overuse of the adsorbents. The fundamental adsorption characteristics of several kinds of activated carbon, activated coke, and carbide wood were examined using 1 ,2,3,4-tetrachlorobenzene as an adsorbate. The removal performance and various equilibrium adsorption characteristics of these adsorbents were analyzed using laboratory-scale adsorption equipment. The equilibrium adsorption amount increased by a factor of 1.9-3.2 at 150 degrees C compared with that at 190 degrees C. The effect of the moisture content on adsorption capacity was relatively small in comparison with that of the temperature. The micropore volume for pore diameters of 2 nm or less was the most important factor governing the adsorption capacity for all adsorbents. Activated carbon showed superior adsorption ability compared to activated coke and carbide wood, although all adsorbents were sufficient for practical use.

  19. M4FT-15OR03100415 - Update on COF-based Adsorbent Survey

    Energy Technology Data Exchange (ETDEWEB)

    Mayes, Richard T. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Dai, Sheng [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

    2015-02-01

    This letter report provides an update on activities focused on generating nanoporous adsorbents involving covalent organic frameworks (COF) and zeolitic imidazolium frameworks (ZIF). The adsorbents have been generated and screened in a uranyl-spiked brine (6 ppm U) to understand uranyl-binding behavior. Porous organic polymers (POP) also qualify under this title and are similar to the COF PPN-6 that is discussed herein. Seven COF/POP and one 1 ZIF were synthesized and screened for uranyl adsorption. Seawater screening is on-going via batch testing while flow screening systems are being developed at PNNL.

  20. The obtainment of carbon adsorbents and their compositions for cleaning industrial wastewater

    OpenAIRE

    JUMAEVA DILNOZA JURAYEVNA; TOIROV OLIMJON ZUVUROVICH

    2016-01-01

    The novel coal adsorbents based on Angren coal have been elaborated. They are the following: a) composite material obtained by addition in coal carbonates of alkaline-earth metals, allowing to rise sorption capacity adsorbent by 70-80% and use it can be used for sewage purification from some ions of inorganic impurities and decreasing of the water rigidity from 16.4 to 0.5 mg∙eq/l; b) heat-treated at 550 °C, with hydrophobic properties (wetting angle α = 99°), a porosity of 30%, capacity to k...

  1. Nicotinic acid as a new co-adsorbent in dye-sensitized solar cells

    Energy Technology Data Exchange (ETDEWEB)

    Nguyen, Phuong Tuyet, E-mail: ntphuong@hcmus.edu.vn [Faculty of Chemistry, University of Science, Vietnam National University, Ho Chi Minh City (Viet Nam); Nguyen, Vinh Son; Phan, Thu Anh Pham; Le, Tan Nhut Van; Le, Duyen My; Le, Duy Dang; Tran, Vy Anh [Faculty of Chemistry, University of Science, Vietnam National University, Ho Chi Minh City (Viet Nam); Huynh, Tuan Van [Faculty of Physics and Engineering Physics, University of Science, Vietnam National University, Ho Chi Minh City (Viet Nam); Lund, Torben [Department of Science, Systems and Models, Roskilde University DK-4000 (Denmark)

    2017-01-15

    Highlights: • Adsorption of Nicotinic acid on TiO{sub 2} surface is characterized by IR and XPS analysis. • The blocking effect of Nicotinic acid toward electron transfer on TiO{sub 2} electrode is indicated by recent developed method of cyclic voltammetry. • Low concentration of Nicotinic acid (<10 mM) helps to increase the amount of dye loading on TiO{sub 2} surface. • The use of Nicotinic acid at optimum concentration improves the efficiency of the resulting DSC from 3.14 to 5.02%. • Nicotinic acid enhances the cell performance by the same extend as other standard co-adsorbents at optimum concentrations. - Abstract: 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 (<10 mM) increased the N719 ruthenium dye loading on the TiO{sub 2} electrode surface by 10–12%, whereas higher concentrations of NTA lowered the dye loading. The adsorption of NTA onto the TiO{sub 2} electrode surface was studied by attenuated total reflectance Fourier transform infrared spectroscopy and X-ray photoelectron spectroscopy, and the blocking effect of NTA toward electron transfer between the electrode and 1,4-dicyanonaphthalene (redox couple electrolyte probe) was investigated by cyclic voltammetry. Subsequently, the performance of NTA in functional DSCs was evaluated by current–voltage (J–V) DSC characterization and compared 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 extent. Specifically, the use of NTA at optimum concentration improved the efficiency of the resulting DSC from 3.14 to 5.02%.

  2. Lithium adsorptive properties of a new selective adsorbent derived from Li1.33Mn1.67O4

    International Nuclear Information System (INIS)

    Miyai, Yoshitaka; Ooi, Kenta; Nishimura, Tomonobu; Kumamoto, Jyunji.

    1994-01-01

    A new selective adsorbent was prepared by the acid treatment of Li 1.33 Mn 1.67 O 4 with spinel structure, followed by granulation with PVC as a binder. The adsorbent showed the highest capacities for lithium from seawater ; the equilibrium lithium uptakes reached 25.5 mg·g -1 by the powdered adsorbent and 18 mg·g -1 by the granulated one at 25degC. The column adsorption study with the granulated adsorbent (diameter 0.7-1.4mm) showed that the lithium uptake reached about 14 mg·g -1 by passing seawater for 30 days. This lithium content is nearly equal to that of lithium ore. Although the lithium adsorption capacity of the granulated adsorbent decreased slightly by repeating the adsorption-desorption cycle, it kept a high capacity as well as a high strength abrasion during the repetition of 10 cycles. (author)

  3. Arsenic removal from water using a novel amorphous adsorbent developed from coal fly ash.

    Science.gov (United States)

    Zhang, Kaihua; Zhang, Dongxue; Zhang, Kai

    2016-01-01

    A novel effective adsorbent of alumina/silica oxide hydrate (ASOH) for arsenic removal was developed through simple chemical reactions using coal fly ash. The iron-modified ASOH with enhancing adsorption activity was further developed from raw fly ash based on the in situ technique. The adsorbents were characterized by X-ray diffraction, Fourier transform infrared spectrometry, scanning electron micrograph, laser particle size and Brunauer-Emmet-Teller surface area. The results show that the adsorbents are in amorphous and porous structure, the surface areas of which are 8-12 times that of the raw ash. The acidic hydrothermal treatment acts an important role in the formation of the amorphous structure of ASOH rather than zeolite crystal. A series of adsorption experiments for arsenic on them were studied. ASOH can achieve a high removal efficiency for arsenic of 96.4% from water, which is more than 2.5 times that of the raw ash. Iron-modified ASOH can enhance the removal efficiency to reach 99.8% due to the in situ loading of iron (Fe). The condition of synthesis pH = 2-4 is better for iron-modified ASOH to adsorb arsenic from water.

  4. Evaluation of pharmaceuticals removal by sewage sludge-derived adsorbents with rapid small-scale column tests

    Science.gov (United States)

    Zhang, P.; Ding, R.; Wallace, R.; Bandosz, T.

    2015-12-01

    New composite adsorbents were developed by pyrolyzing sewage sludge and fish waste (75:25 or 90:10 dry mass ratio) at 650 oC and 950 oC. Batch adsorption experiments demonstrated that the composite adsorbents were able to adsorb a wide range of organic contaminants (volatile organic compounds, pharmaceuticals and endocrine disrupting compounds (EDCs), and nitrosamine disinfection byproducts) with high capacities. Here we further examine the performance of the adsorbents for the simultaneous removal of 8 pharmaceuticals and EDCs with rapid small-scale column tests (RSSCT). Results show that the order of breakthrough in RSSCT is in general consistent with the affinity determined via batch tests. As expected, the maximum amount of adsorption for each compound obtained from RSSCT is identical to or less than that obtained from batch tests (with only one exception), due to adsorption kinetics. However, despite the very different input concentration (1 mg/L vs. 100 mg/L) and contact time (2 min empty bed contact time vs. 16 hour equilibrium time) used in RSSCT and batch tests, the maximum amount of pharmaceuticals and EDCs adsorbed under RSSCT is still about one half of that under equilibrium batch tests, validating the approach of using batch tests with much higher input concentrations to determine adsorption capacities. Results of a pilot-scale column test in a drinking water treatment plant for pharmaceuticals removal will also be presented.

  5. Shrimp pond wastewater treatment using pyrolyzed chicken feather as adsorbent

    Science.gov (United States)

    Moon, Wei Chek; Jbara, Mohamad Hasan; Palaniandy, Puganeshwary; Yusoff, Mohd Suffian

    2017-10-01

    In this study, chicken feather fiber was used as a raw material to prepare a non-expensive adsorbent by pyrolysis without chemical activation. The main pollutants treated in this study were chemical oxygen demand (COD) and ammoniacal nitrogen (NH3-N) from shrimp pond wastewater containing high concentrations of nutrients, which caused the eutrophication phenomenon in adjacent water. Batch adsorption studies were performed to investigate the effect of pH (5-8), mass of adsorbent (0.5-3 g), and shaking time (0.5-2 h) on the removal efficiency of COD and NH3- N. Experimental results showed that the optimum conditions were as follows: pH 5, 0.5 g of adsorbent, and 0.5 h of shaking. Under these conditions, 34.01% and 40.47% of COD and NH3-N were removed, respectively, from shrimp pond wastewater. The adsorption processes were best described by the Langmuir isotherm model for COD and NH3-N removal, with maximum monolayer adsorption capacity of 36.9 and 7.24 mg/g for COD and NH3-N, respectively. The results proved that chicken feather could remove COD and NH3-N from shrimp pond wastewater. However, further studies on thermal treatment should be carried out to increase the removal efficiency of pyrolyzed chicken feather fiber.

  6. Motion of Adsorbed Nano-Particles on Azobenzene Containing Polymer Films

    Directory of Open Access Journals (Sweden)

    Sarah Loebner

    2016-12-01

    Full Text Available We demonstrate in situ recorded motion of nano-objects adsorbed on a photosensitive polymer film. The motion is induced by a mass transport of the underlying photoresponsive polymer material occurring during irradiation with interference pattern. The polymer film contains azobenzene molecules that undergo reversible photoisomerization reaction from trans- to cis-conformation. Through a multi-scale chain of physico-chemical processes, this finally results in the macro-deformations of the film due to the changing elastic properties of polymer. The topographical deformation of the polymer surface is sensitive to a local distribution of the electrical field vector that allows for the generation of dynamic changes in the surface topography during irradiation with different light interference patterns. Polymer film deformation together with the motion of the adsorbed nano-particles are recorded using a homemade set-up combining an optical part for the generation of interference patterns and an atomic force microscope for acquiring the surface deformation. The particles undergo either translational or rotational motion. The direction of particle motion is towards the topography minima and opposite to the mass transport within the polymer film. The ability to relocate particles by photo-induced dynamic topography fluctuation offers a way for a non-contact simultaneous manipulation of a large number of adsorbed particles just in air at ambient conditions.

  7. Determination of Vanadium Binding Mode on Seawater-Contacted Polyamidoxime Adsorbents

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Zhicheng [Lawrence Berkeley National Laboratory (LBNL); Rao, Linfeng [Lawrence Berkeley National Laboratory (LBNL); Abney, Carter W. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Bryantsev, Vyacheslav [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Ivanov, Aleksandr [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

    2017-09-01

    Adsorbents developed for the recovery of uranium from seawater display poor selectivity over other transition metals present in the ocean, with vanadium particularly problematic. To improve selectivity, an indispensable step is the positive identification of metal binding environments following actual seawater deployment. In this work we apply x-ray absorption fine structure (XAFS) spectroscopy to directly investigate the vanadium binding environment on seawater-deployed polyamidoxime adsorbents. Comparison of the x-ray absorption near edge spectra (XANES) reveal marked similarities to recently a reported non-oxido vanadium (V) structure formed upon binding with cyclic imidedioxime, a byproduct of generating amidoxime functionalities. Density functional theory (DFT) calculations provided a series of putative vanadium binding environments for both vanadium (IV) and vanadium (V) oxidation states, and with both amidoxime and cyclic imidedioxime. Fits of the extended XAFS (EXAFS) data confirmed vanadium (V) is bound exclusively by the cyclic imidedioxime moiety in a 1:2 metal:ligand fashion, though a modest structural distortion is also observed compared to crystal structure data and computationally optimized geometries which is attributed to morphology effects from the polymer graft chain and the absence of crystal packing interactions. These results demonstrate that improved selectivity for uranium over vanadium can be achieved by suppressing the formation of cyclic imidedioxime during preparation of polyamidoxime adsorbents for seawater uranium recovery.

  8. Adsorptivity of uranium by aluminium-activated carbon composite adsorbent

    International Nuclear Information System (INIS)

    Katoh, Shunsaku; Sugasaka, Kazuhiko; Fujii, Ayako; Takagi, Norio; Miyai, Yoshitaka

    1976-01-01

    To research the adsorption process of uranium from sea water by aluminium-activated carbon composite adsorbent (C-Al-OH), the authors examined the effects of temperature, pH and carbonate ion concentration of the solution upon the adsorption of uranium, using sodium chloride solution and natural sea water. The continued mixing of the solution for the duration of two to four hours was required to attain the apparent equilibrium of adsorption. The adsorption velocity at an early stage and the uptake of uranium at the final stage showed an increase in proportion to a rise in the adsorption temperature. In the experiment of adsorption for which sodium chloride solution was used, the linear relationship between the logarithm of the distribution coefficient (K sub(d)) and the pH of the solution was recognized. The uptake of the uranium from the solution at the pH of 12 increased as the carbonate ion concentration in the solution decreased. The uranyl ion in the natural sea water was assumed to be uranyl carbonate complex ion (UO 2 (CO 3 ) 3 4- ). As the result of the calculation conducted by using the formation constants for uranyl complexes in literature, it was found that uranyl hydroxo complex ion (UO 2 (OH) 3 - ) increased in line with a decrease of the carbonate ion concentration in the solution. The above results of the experiment suggested that the adsorption of uranium by the adsorbent (C-Al-OH) was cationic adsorption or hydrolysis adsorption being related with the active proton on the surface of the adsorbent. (auth.)

  9. The design of a modular pilot plant based on the adsorber loop concept

    International Nuclear Information System (INIS)

    Koske, P.H.; Ohlrogge, K.

    1984-01-01

    The main design criteria for a pilot plant producing about 100 t uranium per year from seawater are discussed. The application of the ''adsorber loop concept'' for the contact between seawater and the adsorber granulate enables the employment of high seawater velocities. The seawater flow is accomplished by active pumping and the plant is supposed to be operating far from shores. Besides some informations on the theoretical background the essential engineering considerations are presented. (orig.) [de

  10. Adsorber fires

    International Nuclear Information System (INIS)

    Holmes, W.

    1987-01-01

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

  11. Adsorbent filled membranes for gas separation. Part 1. Improvement of the gas separation properties of polymeric membranes by incorporation of microporous adsorbents

    NARCIS (Netherlands)

    Duval, J.M.; Duval, J.-M.; Folkers, Albertje; Mulder, M.H.V.; Desgrandchamps, G.; Smolders, C.A.; Smolders, C.A.

    1993-01-01

    The effect of the introduction of specific adsorbents on the gas separation properties of polymeric membranes has been studied. For this purpose both carbon molecular sieves and zeolites are considered. The results show that zeolites such as silicate-1, 13X and KY improve to a large extent the

  12. Magnetic-supported cucurbituril: A recyclable adsorbent for the ...

    Indian Academy of Sciences (India)

    Administrator

    removal of humic acid from simulated water. QIN YANG* ... The commonly used adsorbents are activated carbon. (Deng and Bai ... Q[n] is practically insoluble in all common organic solvents. ... Q[n] has other advantages such as its strong rigid structure .... and it does not result in the phase change of Fe3O4. In addition ...

  13. Mercury chemisorption by sulfur adsorbed in porous materials

    NARCIS (Netherlands)

    Steijns, M.; Peppelenbos, A.; Mars, P.

    1976-01-01

    The sorption of mercury vapor by adsorbed sulfur in the zeolites CaA (= 5A) and NaX (=13X) and two types of active carbon has been measured at a temperature of 50°C. With increasing degree of micropore filling by sulfur the fraction of sulfur accessible to mercury atoms decreased for CaA and NaX.

  14. Elucidating the effects of adsorbent flexibility on fluid adsorption using simple models and flat-histogram sampling methods

    International Nuclear Information System (INIS)

    Shen, Vincent K.; Siderius, Daniel W.

    2014-01-01

    Using flat-histogram Monte Carlo methods, we investigate the adsorptive behavior of the square-well fluid in two simple slit-pore-like models intended to capture fundamental characteristics of flexible adsorbent materials. Both models require as input thermodynamic information about the flexible adsorbent material itself. An important component of this work involves formulating the flexible pore models in the appropriate thermodynamic (statistical mechanical) ensembles, namely, the osmotic ensemble and a variant of the grand-canonical ensemble. Two-dimensional probability distributions, which are calculated using flat-histogram methods, provide the information necessary to determine adsorption thermodynamics. For example, we are able to determine precisely adsorption isotherms, (equilibrium) phase transition conditions, limits of stability, and free energies for a number of different flexible adsorbent materials, distinguishable as different inputs into the models. While the models used in this work are relatively simple from a geometric perspective, they yield non-trivial adsorptive behavior, including adsorption-desorption hysteresis solely due to material flexibility and so-called “breathing” of the adsorbent. The observed effects can in turn be tied to the inherent properties of the bare adsorbent. Some of the effects are expected on physical grounds while others arise from a subtle balance of thermodynamic and mechanical driving forces. In addition, the computational strategy presented here can be easily applied to more complex models for flexible adsorbents

  15. Preparation of carbon dioxide adsorbents from the chemical activation of urea-formaldehyde and melamine-formaldehyde resins

    Energy Technology Data Exchange (ETDEWEB)

    T.C. Drage; A. Arenillas; K.M. Smith; C. Pevida; S. Piippo; C.E. Snape [University of Nottingham, Nottingham (United Kingdom). Nottingham Fuel and Energy Centre, School of Chemical, Environmental and Mining Engineering

    2007-01-15

    Adsorption is considered to be one of the more promising technologies for the capture of CO{sub 2} from flue gases. In general, nitrogen enrichment is reported to be effective in enhancing the specific adsorbent-adsorbate interaction for CO{sub 2}. Nitrogen enriched carbons were produced from urea-formaldehyde and melamine-formaldehyde resins polymerised in the presence of K{sub 2}CO{sub 3} as a chemical activation agent, with activation undertaken over a range of temperatures. CO{sub 2} adsorption capacity was determined to be dependent upon both textural properties and more importantly nitrogen functionality. Adsorbents capable of capturing above 8 wt.% CO{sub 2} at 25{sup o}C were produced from the chemical activation of urea-formaldehyde resin at 500{sup o}C. Chemical activation seems to produce more effective adsorbents than CO{sub 2} activation. 29 refs., 4 figs., 3 tabs.

  16. Characterization of Activated Carbon from Coal and Its Application as Adsorbent on Mine Acid Water Treatment

    Directory of Open Access Journals (Sweden)

    Siti Hardianti

    2017-06-01

    Full Text Available Anthracite and Sub-bituminous as activated carbon raw material had been utilized especially in mining field as adsorbent of dangerous heavy metal compound resulted in mining activity. Carbon from coal was activated physically and chemically in various temperature and particle sizes. Characterization was carried out in order to determine the adsorbent specification produced hence can be used and applied accordingly. Proximate and ultimate analysis concluded anthracite has fixed carbon 88.91% while sub-bituminous 49.05%. NaOH was used in chemical activation while heated at 400-500°C whereas physical activation was conducted at 800-1000°C. Activated carbon has high activity in adsorbing indicated by high iodine number resulted from analysis. SEM-EDS result confirmed that activated carbon made from coal has the quality in accordance to SNI and can be used as adsorbent in acid water treatment.

  17. Reduce NOx Emissions by Adsorber-Reduction Catalyst on Lean Burn Gasoline Engine

    Directory of Open Access Journals (Sweden)

    Dongpeng Yue

    2013-09-01

    Full Text Available The effect of a new catalyst system composed of traditional three way catalyst converter and adsorber-reduction catalysis converter on the emission characteristics and BSFC (Breake Specific Fuel Consumption- BSFCof a lean burn gasoline engine operated were investigated in this paper under different schemes of catalyst converter arrangement and different speeds and loads. The results show that the position of Three Way Catalyst is before the NOx adsorber Catalyst was the best scheme of catalyst converter arrangement. Which has the highest converter efficiency of reduction NOx emission in lean burn gasoline engine. The effects of speed on the exhaust emission and BSFC were also related to the ratio of lean burn time to rich burn time and the absolute value of both time of the adsorber-reduction catalyst converter. The load of the engine was the main influential factor to the exhaust emission characteristics and BSFC of lean burn gasoline engine, and the more load of the engine was, the more NOx emission , the less NOx conversion rate (CNOx and the better BSFC were.

  18. Syntheses of amine-type adsorbents with emulsion graft polymerization of glycidyl methacrylate

    International Nuclear Information System (INIS)

    Seko, N.; Bang, L.T.; Tamada, M.

    2007-01-01

    Glycidyl methacrylate (GMA) which was precursor monomer for the synthesis of metal ion adsorbent was emulsified by surfactant of Tween 20 (Tw-20). The emulsion of 5% GMA in the water was stable for 48 h at Tw-20 concentration of 0.5%. Graft polymerization of GMA on polyethylene fiber was carried out in the emulsion state at various pre-irradiation doses. Degree of grafting (Dg) reached 103%, 301% and 348% for 1 h grafting at 40 deg. C with pre-irradiation of 10, 30 and 40 kGy, respectively. But the Dg was depressed when the pre-irradiation dose was over 50 kGy since cross-linking occurred simultaneously in the trunk polymer. Dg decreased with increment of Tw-20 concentration in emulsion of 5% GMA at pre-irradiation of 40 kGy. The three kinds of amine-type adsorbents were synthesized by reacting diethylenetriamine (DETA), triethylenetetramine (TETA) and ethylenediamine (EDA) with GMA-grafted polyethylene fiber. The synthesized EDA-type adsorbent had the highest selectivity against U ion and the distribution coefficient was 2.0 x 10 6

  19. Clarification of the mechanism of sulfur trioxide electrolysis. Evaluation of SO3 and O atom adsorbed on Pt surface

    International Nuclear Information System (INIS)

    Suzuki, Chikashi; Nakagiri, Toshio

    2008-01-01

    We developed a hybrid thermo-chemical process, which included a SO 3 electrolysis process utilizing the heat supplied by a fast breeder reactor (FBR), as a new hydrogen production process. To clarify the mechanism of SO 3 electrolysis, we evaluated the electronic states of SO 3 and O atom adsorbed on the Pt (111) surface using first-principles calculations with a slab model. Moreover, we evaluated the chemical bonding states of SO 3 and adsorbed O using molecular orbital calculation on the basis of the calculations using a slab model. We found that there were two stable adsorbed SO 3 configurations on the Pt surface. From the molecular orbital calculation, it was found that the S-O bond became weak by SO 3 absorption, and it was conjectured that SO 3 dissociation proceeded through the intermediate state of adsorbed SO 2 and adsorbed O on the Pt surface. Moreover, we derived the O coverage considering the adsorbed SO 2 and evaluated the influence of SO 3 adsorption energy on the O coverage. (author)

  20. Breakthrough indicator for aromatic VOCs using needle trap samplers for activated carbon adsorbent.

    Science.gov (United States)

    Cheng, Wen-Hsi; Jiang, Jia-Rong; Huang, Yi-Ning; Huang, Shiun-Chian; Yu, Yan-Pin

    2012-08-01

    Internal circulation cabinets equipped with granular activated carbon (GAC) for adsorbing volatile organic compounds (VOCs) are widely used to store bottles containing organic solvents in universities, colleges, and hospital laboratories throughout Taiwan. This work evaluates the VOC adsorption capacities of GAC using various adsorption times for gas stream mixtures of 100 ppm toluene and 100 ppm o-xylene. Additionally, needle trap sampling (NTS) technology was used to indicate the time for renewing the GAC to avoid VOC breakthrough from adsorbents. Experimental results demonstrate that the proposed models can linearly express toluene and o-xylene adsorption capacities as the natural logarithm of adsorption time (ln(t)) and can accurately simulate the equilibrium adsorption capacities (Qe, g VOCs/g GAC) for gaseous toluene and o-xylene. The NTS, packed with 60-80 mesh divinylbenzene (DVB) particles, was compared in terms of extraction efficiency by simultaneously using the 75-microm Carboxen/polydimethylsiloxane-solid-phase microextraction (Carboxen/PDMS-SPME) fiber for time-weighted average (TWA) sampling, and experimental results indicated that the packed DVB-NTS achieved higher toluene extraction rates. Additionally, the NTS installed in the outlet air stream for adsorbing toluene and o-xylene exhausted through GAC accurately indicated toluene and o-xylene breakthrough times of 4700-5000 min. The GAC-NTS operational instructions to indicate the replacing time of adsorbent in the internal circulation cabinets are also included in this paper.

  1. Effect of nitrogen doping on titanium carbonitride-derived adsorbents used for arsenic removal

    Energy Technology Data Exchange (ETDEWEB)

    Han, Jisun [Department of Materials Science and Engineering, Seoul National University, Seoul 151-742 (Korea, Republic of); Lee, Soonjae [Center for Water Resource Cycle Research, Korea Institute of Science and Technology, Hwarang-ro 14-gil 5, Seongbuk-gu, Seoul 136-791 (Korea, Republic of); Choi, Keunsu [Computational Science Research Center, Korea Institute of Science and Technology, Hwarang-ro 14-gil 5, Seongbuk-gu, Seoul 136-791 (Korea, Republic of); Kim, Jinhong [Samsung Electronics Co.Ltd.,(Maetan dong) 129, Samsung-ro Yeongtong-gu, Suwonsi, Gyeonggi-do 443-742, Repubilc of Korea (Korea, Republic of); Ha, Daegwon [Department of Materials Science and Engineering, Seoul National University, Seoul 151-742 (Korea, Republic of); Lee, Chang-Gu [Center for Water Resource Cycle Research, Korea Institute of Science and Technology, Hwarang-ro 14-gil 5, Seongbuk-gu, Seoul 136-791 (Korea, Republic of); An, Byungryul [Department of Civil Engineering, Sangmyung University, Cheonan, Chungnam 31066 (Korea, Republic of); Lee, Sang-Hyup [Center for Water Resource Cycle Research, Korea Institute of Science and Technology, Hwarang-ro 14-gil 5, Seongbuk-gu, Seoul 136-791 (Korea, Republic of); Mizuseki, Hiroshi, E-mail: mizuseki@kist.re.kr [Computational Science Research Center, Korea Institute of Science and Technology, Hwarang-ro 14-gil 5, Seongbuk-gu, Seoul 136-791 (Korea, Republic of); Choi, Jae-Woo, E-mail: plead36@kist.re.kr [Center for Water Resource Cycle Research, Korea Institute of Science and Technology, Hwarang-ro 14-gil 5, Seongbuk-gu, Seoul 136-791 (Korea, Republic of); Department of Energy and Environmental Engineering, University of Science and Technology (UST), Daejeon 305-350 (Korea, Republic of); Kang, Shinhoo, E-mail: shinkang@snu.ac.kr [Department of Materials Science and Engineering, Seoul National University, Seoul 151-742 (Korea, Republic of)

    2016-01-25

    Highlights: • The N-doping can improve the As adsorption performance of carbon-based materials. • The material features high micro- and small meso-pores with exceptional surface area. • Pyrrolic N atoms distributed uniformly on the micropores act as adsorption sites. • The synthesis temperature affected pore properties and surface functional groups. - Abstract: Arsenic in water and wastewater is considered to be a critical contaminant as it poses harmful health risks. In this regard, to meet the stringent regulation of arsenic in aqueous solutions, nitrogen doped carbon-based materials (CN) were prepared as adsorbents and tested for the removal of arsenic ion from aqueous solutions. Nitrogen-doped carbon (CNs) synthesized by chlorination exhibited well-developed micro- and small meso-pores with uniform pore structures. The structure and characteristics of the adsorbents thus developed were confirmed by field-emission scanning electron microscopy, transmission electron microscopy, Brunauer–Emmett–Teller analysis, X-ray diffraction, X-ray photoelectron spectroscopy, and Fourier transform infrared spectroscopy. Among the CNs developed, CN700 exhibited high adsorption capacity for arsenic (31.08 mg/g). The adsorption efficiency for arsenic ion was confirmed to be affected by pyrrolic nitrogen and micro-pores. These results suggest that CNs are useful adsorbents for the treatment of arsenic, and in particular, CN700 demonstrates potential for application as an adsorbent for the removal of anionic heavy metals from wastewater and sewage.

  2. Removal of Indigo Carmine Dye from Aqueous Solution Using Magnesium Hydroxide as an Adsorbent

    Directory of Open Access Journals (Sweden)

    Thimmasandra Narayan Ramesh

    2015-01-01

    Full Text Available Magnesium hydroxide is used as an adsorbent for the removal of indigo carmine dye from aqueous solution. We have investigated the effectiveness of removal of indigo carmine dye from aqueous solutions at pH 6-7 and 12-13 using magnesium hydroxide thereby varying the dose of the adsorbent, concentration of the dye, duration, and temperature. Structural transformations of adsorbent during the adsorption process at different pH values are monitored using powder X-ray diffraction and infrared spectroscopy. Different types of adsorption isotherm models were evaluated and it was found that Langmuir isotherm fits well at both pH values (6-7 and 12-13. Adsorption of indigo carmine onto magnesium hydroxide at pH 6-7/pH 12-13 follows pseudo-second order rate kinetics.

  3. A heat transfer correlation for transient vapor uptake of powdered adsorbent embedded onto the fins of heat exchangers

    KAUST Repository

    Li, Ang

    2015-10-23

    We present a detailed study on the transient heat transfer phenomena of powdered-adsorbent mixed with an organic binder for adherence to the fins of a heat exchangers. The transient performance of such an adsorbent-heat exchanger configuration has significant application potential in the adsorption desalination plants and chillers but seldom addressed in the literature. An experiment is designed to measure the heat transfer for several adsorption temperatures under a single vapor component environment. Analysis on the experimental data indicates that the adsorbent-adsorbate interactions contribute about 75% of the total thermal resistances throughout the uptake processes. It is found that the initial local adsorption heat transfer coefficients are significantly higher than the average values due primarily to the thermal mass effect of the adsorbent–adsorbate interaction layers. From these experiments, a correlation for the transient local adsorption heat transfer coefficients is presented at the sub-atmospheric pressures and assorted application temperatures.

  4. Waste-based alternative adsorbents for the remediation of pharmaceutical contaminated waters: Has a step forward already been taken?

    Science.gov (United States)

    Silva, Carla Patrícia; Jaria, Guilaine; Otero, Marta; Esteves, Valdemar I; Calisto, Vânia

    2018-02-01

    When adsorption is considered for water treatment, commercial activated carbon is usually the chosen adsorbent for the removal of pollutants from the aqueous phase, particularly pharmaceuticals. In order to decrease costs and save natural resources, attempts have been made to use wastes as raw materials for the production of alternative carbon adsorbents. This approach intends to increase efficiency, cost-effectiveness, and also to propose an alternative and sustainable way for the valorization/management of residues. This review aims to provide an overview on waste-based adsorbents used on pharmaceuticals' adsorption. Experimental facts related to the adsorption behaviour of each adsorbent/pharmaceutical pair and some key factors were addressed. Also, research gaps that subsist in this research area, as well as future needs, were identified. Simultaneously, this review aims to clarify the current status of the research on pharmaceuticals' adsorption by waste-based adsorbents in order to recognize if the right direction is being taken. Copyright © 2017 Elsevier Ltd. All rights reserved.

  5. Study on development of adsorbent of acetaldehyde; Acetaldehyde yo kyuchakuzai no kaihatsu ni kansuru kenkyu

    Energy Technology Data Exchange (ETDEWEB)

    Noda, T. [Nippon Steel Corp., Tokyo (Japan); Suzuki, M. [The University of Tokyo, Tokyo (Japan). Institute of Industrial Science

    1997-07-10

    The adsorption of acetaldehyde by porous ceramics impregnated with hydrazinium aluminum sulfate (HAS) is studied. Silicagel, activated alumina, activated clay, and activated carbon are compared, and it is found that silicagel and activated clay are suitable as a substrate for HAS impregnated adsorbent. The adsorption mechanism of acetaldehyde by the adsorbent is believed to be one in which acetaldehyde reacts with hydrazinium and yields acetaldazine. The adsorption capacity of the adsorbent at low acetaldehyde concentration of 0.1 ppm was as large as 1.36 mol/kg. This adsorption capacity at 0.1 ppm acetaldehyde concentration is remarkably larger than that of conventional activated carbon. Hydrazinium decomposes easily in the air because it is a strong reducing agent and reacts with oxygen or carbon dioxide. But hydrazinium impregnated on porous ceramics with HAS becomes more stable and maintains reactivity with acetaldehyde for longer than six months. An adsorbent made of porous ceramics impregnated with HAS is useful as a deodorant for acetaldehyde. 8 refs., 6 figs., 6 tabs.

  6. Ceramics adsorbing virus and cells. Uirusu, saibo bunri ceramics

    Energy Technology Data Exchange (ETDEWEB)

    Hiraide, T. (Asahi Optical Co. Ltd., Tokyo (Japan))

    1993-07-01

    It has been reported that hydroxyapatite (HA), which is the main inorganic component of teeth and bones of homo sapiens and used for biomaterials such as artificial tooth roots, adsorbs viruses such as influenza viruses. In this article, the history of development up to now of HA and its adsorption mechanism of protein, virus, etc., are introduced. HA was applied for chromatography in 1956 becoming one of the separating and refining methods of protein and nucleic acid, then after the development of spherical porous HA, it has become applied for high speed liquid chromatography (HPLC). Also by means of a column filled with HA granules, T-cells have been able to be purified in a short time from lymphocyte which was separated from the blood of homo sapiens. Recently it has also been reported that HA granules can adsorb influenza viruses, Japanese encephalitis viruses, polio viruses and hepatitis B viruses, and a cold-preventative mask based upon this report is now on sale. 11 refs., 7 figs.

  7. Comparison of pre and post-combustion CO{sub 2} adsorbent technologies

    Energy Technology Data Exchange (ETDEWEB)

    T.C. Drage; A. Arenillas; K. Smith; C.E. Snape [University of Nottingham, Nottingham (United Kingdom). Nottingham Fuel and Energy Centre, School of Chemical, Environmental and Mining Engineering

    2006-07-01

    Adsorption is considered to be one of the most promising techniques for the capture of CO{sub 2} from flue gases. The application of adsorption to both post-combustion capture at pressures close to ambient and for high pressure pre-combustion capture applications, for example IGCC, are explored. Adsorption capacities as a function of adsorbent properties as well as strategies for regeneration, both thermal swing and pressure swing are described. Adsorption at both low and high pressures requires chemical and physical adsorbents respectively. Adsorption at high pressure has the advantage of potential temperature swing regeneration whilst maintaining CO{sub 2} pressure, reducing the overall costs associated with re-compression of the gas for transportation.

  8. The behavior of xenon dynamic adsorption on granular activated carbon packed bed adsorber

    International Nuclear Information System (INIS)

    Chongyang Zhou; Shujuan Feng; Guoqing Zhou; Yuren Jin; Junfu Liang; Jingming Xu

    2011-01-01

    In order to retard radioxenon release into the atmosphere from nuclear power station or to sensitively monitor its concentration to ensure environmental and human safety, it is necessary to know the behavior of xenon dynamic adsorption on granular activated carbon pack bed adsorber. The quantities, including the dynamic adsorption coefficient (k d ), the amount of xenon adsorbed (q), the length of mass transfer zone (L MTZ ) and the length of the unused bed (LUB), used to describe the adsorption behavior, were sorted out and calculated. The factors, including xenon concentrations, pressures and temperatures, to affect these quantities were investigated. The results show that: (1) The values of k d and q decrease with increasing temperatures, but increase with increasing pressures, (2) The values of L MTZ and LUB increase with increasing temperatures or pressures, but are independent of concentrations. Knowledge of these quantities is very helpful for packed bed adsorber operation. (author)

  9. Melatonin Nanoparticles Adsorbed to Polyethylene Glycol Microspheres as Activators of Human Colostrum Macrophages

    International Nuclear Information System (INIS)

    Hara, C.D.C.P.; Honorio-Frana, A.C.; Fagundes, D.L.G.; Guimares, P.C.L.; Franca, E.L.

    2013-01-01

    The effectiveness of hormones associated with polymeric matrices has amplified the possibility of obtaining new drugs to activate the immune system. Melatonin has been reported as an important immunomodulatory agent that can improve many cell activation processes. It is possible that the association of melatonin with polymers could influence its effects on cellular function. Thus, this study verified the adsorption of the hormone melatonin to polyethylene glycol (PEG) microspheres and analyzed its ability to modulate the functional activity of human colostrum phagocytes. Fluorescence microscopy and flow cytometry analyses revealed that melatonin was able to adsorb to the PEG microspheres. This system increased the release of superoxide and intracellular calcium. There was an increase of phagocytic and microbicidal activity by colostrum phagocytes when in the presence of melatonin adsorbed to PEG microspheres. The modified delivery of melatonin adsorbed to PEG microspheres may be an additional mechanism for its microbicidal activity and represents an important potential treatment for gastrointestinal infections of newborns.

  10. Melatonin Nanoparticles Adsorbed to Polyethylene Glycol Microspheres as Activators of Human Colostrum Macrophages

    Directory of Open Access Journals (Sweden)

    Cristiane de Castro Pernet Hara

    2013-01-01

    Full Text Available The effectiveness of hormones associated with polymeric matrices has amplified the possibility of obtaining new drugs to activate the immune system. Melatonin has been reported as an important immunomodulatory agent that can improve many cell activation processes. It is possible that the association of melatonin with polymers could influence its effects on cellular function. Thus, this study verified the adsorption of the hormone melatonin to polyethylene glycol (PEG microspheres and analyzed its ability to modulate the functional activity of human colostrum phagocytes. Fluorescence microscopy and flow cytometry analyses revealed that melatonin was able to adsorb to the PEG microspheres. This system increased the release of superoxide and intracellular calcium. There was an increase of phagocytic and microbicidal activity by colostrum phagocytes when in the presence of melatonin adsorbed to PEG microspheres. The modified delivery of melatonin adsorbed to PEG microspheres may be an additional mechanism for its microbicidal activity and represents an important potential treatment for gastrointestinal infections of newborns.

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

    Science.gov (United States)

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

    2006-06-01

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

  12. Versatile nature of hetero-chitosan based derivatives as biodegradable adsorbent for heavy metal ions; a review.

    Science.gov (United States)

    Ahmad, Mudasir; Manzoor, Kaiser; Ikram, Saiqa

    2017-12-01

    The polyfunctional chitosan can act as the biological macromolecule ligand not only for the adsorption and the recovery of metal ions from an aqueous media, but also for the fabrication of novel adsorbents which shows selectivity and better adsorption properties. The unmodified chitosan itself, a single cationic polysaccharide, has hydroxyl and amine groups carrying complex properties with the metal ions. In addition, the selectivity of metal ions, the adsorption efficiency and adsorption capacity of the adsorbent can be modified chemically. This review covers the synthetic strategies of chitosan towards the synthesis of hetero-chitosan based adsorbents via chemical modifications in past two decades. It also includes how chemical modification influences the metal adsorption with N, O, S and P containing chitosan derivatives. Hope this review article provides an opportunity for researchers in the future to explore the potential of chitosan as an adsorbent for removal of metal ions from wastewater. Copyright © 2017 Elsevier B.V. All rights reserved.

  13. Elution of Uranium and Transition Metals from Amidoxime-Based Polymer Adsorbents for Sequestering Uranium from Seawater

    Energy Technology Data Exchange (ETDEWEB)

    Pan, Horng-Bin; Kuo, Li-Jung; Wai, Chien M.; Miyamoto, Naomi; Joshi, Ruma; Wood, Jordana R.; Strivens, Jonathan E.; Janke, Christopher J.; Oyola, Yatsandra; Das, Sadananda; Mayes, Richard T.; Gill, Gary A.

    2015-11-30

    High-surface-area amidoxime and carboxylic acid grafted polymer adsorbents developed at Oak Ridge National Laboratory were tested for sequestering uranium in a flowing seawater flume system at the PNNL-Marine Sciences Laboratory. FTIR spectra indicate that a KOH conditioning process is necessary to remove the proton from the carboxylic acid and make the sorbent effective for sequestering uranium from seawater. The alkaline conditioning process also converts the amidoxime groups to carboxylate groups in the adsorbent. Both Na2CO3-H2O2 and hydrochloric acid elution methods can remove ~95% of the uranium sequestered by the adsorbent after 42 days of exposure in real seawater. The Na2CO3-H2O2 elution method is more selective for uranium than conventional acid elution. Iron and vanadium are the two major transition metals competing with uranium for adsorption to the amidoxime-based adsorbents in real seawater.

  14. Aging assessment of nuclear air-treatment system HEPA filters and adsorbers

    International Nuclear Information System (INIS)

    Winegardner, W.K.

    1993-08-01

    A Phase I aging assessment of high-efficiency particulate air (HEPA) filters and activated carbon gas adsorption units (adsorbers) was performed by the Pacific Northwest Laboratory (PNL) as part of the US Nuclear Regulatory Commission's (NRC) Nuclear Plant Aging Research (NPAR) Program. Information concerning design features; failure experience; aging mechanisms, effects, and stressors; and surveillance and monitoring methods for these key air-treatment system components was compiled. Over 1100 failures, or 12 percent of the filter installations, were reported as part of a Department of Energy (DOE) survey. Investigators from other national laboratories have suggested that aging effects could have contributed to over 80 percent of these failures. Tensile strength tests on aged filter media specimens indicated a decrease in strength. Filter aging mechanisms range from those associated with particle loading to reactions that alter properties of sealants and gaskets. Low radioiodine decontamination factors associated with the Three Mile Island (TMI) accident were attributed to the premature aging of the carbon in the adsorbers. Mechanisms that can lead to impaired adsorber performance include oxidation as well as the loss of potentially available active sites as a result of the adsorption of pollutants. Stressors include heat, moisture, radiation, and airborne particles and contaminants

  15. Oxidative Degradation of Aminosilica Adsorbents Relevant to Postcombustion CO 2 Capture

    KAUST Repository

    Bollini, Praveen

    2011-05-19

    Coal-fired power plant flue gas exhaust typically contains 3-10% oxygen. While it is known that the monoethanolamine (MEA) oxidative degradation rate is a critical parameter affecting liquid amine absorption processes, the effect of oxygen on the stability of solid amine adsorbents remains unexplored. Here, oxidative degradation of aminosilica materials is studied under accelerated oxidizing conditions to assess the stability of different supported amine structures to oxidizing conditions. Adsorbents constructed using four different silane coupling agents are evaluated, three with a single primary, secondary, or tertiary amine at the end of a propyl surface linker, with the fourth having one secondary propylamine separated from a primary amine by an ethyl linker. Under the experimental conditions used in this study, it was found that both amine type and proximity had a significant effect on oxidative degradation rates. In particular, the supported primary and tertiary amines proved to be stable to the oxidizing conditions used, whereas the secondary amines degraded at elevated treatment temperatures. Because secondary amines are important components of many supported amine adsorbents, it is suggested that the oxidative stability of such species needs to be carefully considered in assessments of postcombustion CO2 capture processes based on supported amines. © 2011 American Chemical Society.

  16. Oxidative Degradation of Aminosilica Adsorbents Relevant to Postcombustion CO 2 Capture

    KAUST Repository

    Bollini, Praveen; Choi, Sunho; Drese, Jeffrey H.; Jones, Christopher W.

    2011-01-01

    Coal-fired power plant flue gas exhaust typically contains 3-10% oxygen. While it is known that the monoethanolamine (MEA) oxidative degradation rate is a critical parameter affecting liquid amine absorption processes, the effect of oxygen on the stability of solid amine adsorbents remains unexplored. Here, oxidative degradation of aminosilica materials is studied under accelerated oxidizing conditions to assess the stability of different supported amine structures to oxidizing conditions. Adsorbents constructed using four different silane coupling agents are evaluated, three with a single primary, secondary, or tertiary amine at the end of a propyl surface linker, with the fourth having one secondary propylamine separated from a primary amine by an ethyl linker. Under the experimental conditions used in this study, it was found that both amine type and proximity had a significant effect on oxidative degradation rates. In particular, the supported primary and tertiary amines proved to be stable to the oxidizing conditions used, whereas the secondary amines degraded at elevated treatment temperatures. Because secondary amines are important components of many supported amine adsorbents, it is suggested that the oxidative stability of such species needs to be carefully considered in assessments of postcombustion CO2 capture processes based on supported amines. © 2011 American Chemical Society.

  17. Synthesis and characterization of sulfur-functionalized silica nanocapsules as mercury adsorbents

    Science.gov (United States)

    Palaniappan, Thenappan; Saman, Norasikin; Mat, Hanapi; Johari, Khairiraihanna

    2017-12-01

    Sulfur functionalized silica nanocapsules (S-SiNC) was successfully synthesized and characterized as a potential adsorbent for industrial applications. The synthesis of S-SiNC was carried out using the mircoemulsion templating method using cetyltrimethylammonium bromide (CTAB) as cationic surfactant, toluene as co-solvent, ammonia solution as catalyst, and tetraethylorthosilicate (TEOS) as the silica base. The S-SiNC adsorbent was characterized using Transmission Electron Microscope, Fourier Transformed Infra Red spectroscopy and nitrogen adsorption/desorption analysis. The physical and chemical properties of the SiNC changed as a result of the functionalization, hence affecting the extent of Hg(II) adsorption. The S-SiNCs were also tested in mercury ion [Hg(II)] adsorption via batch adsorption process with variation in initial Hg (II) concentration. It was found that there is a significant improvement in Hg(II) adsorption performance after being functionalized with elemental sulfur. The highest Hg(II) adsorption capacity was obtained for S-SiNC (107.875 mg/g), which significantly outperformed the blank SiNC. The experimental data obtained was found to be fitting well to the Langmuir isotherm model (R2= 0.979) compared to Freundlich isotherm model. Thus, the results demonstrated the potential application of sulfur functionalized silica nanocapsules as adsorbent in industrial applications.

  18. Al2O3-Cact-(CuO, Cr2O3, Co3O4 Adsorbents-Catalysts: Preparation and Characterization

    Directory of Open Access Journals (Sweden)

    Gitana DABRILAITĖ-KUDŽMIENĖ

    2013-03-01

    Full Text Available Al2O3-Cact-(CuO, Cr2O3 Co3O4 adsorbents-catalysts were prepared using Al2O3-Cact (alumina gel–activated carbon adsorbent and different amount of CuO, Cr2O3 and Co3O4. The active components were incorporated into wet alumina gel–carbon mixture using different conditions (by sol-gel method and mixing a milled metal oxides. Equilibrium adsorptive capacity measurements of alcohol vapours were carried out in order to determine the influence of preparation conditions on the stability of prepared adsorbents–catalysts. Specific surface area of the prepared adsorbents-catalysts were measured by BET method. It was established that for adsorbent-catalyst produced by sol-gel method SBET = 244.7 m2/g. Surface area SBET = 29.32 m2/g was obtained for adsorbent-catalyst with metal oxides. On the basis of these results it was assumed that active carbon was lost in this adsorbent-catalyst during the preparation process. Sol-gel derived adsorbent–catalyst was tested for the oxidation of methanol vapours. Catalytic oxidation was carried out in fixed-bed reactor. Experimental data indicate that adsorptive capacity of the adsorbent–catalyst is (3.232 – 3.259 mg/m3 CH3OH at relative air humidity is 40 % – 50 %. During a fast heating of CH3OH – saturated adsorbent-catalyst a part of adsorbate is converted to CO2 and H2O. Methanol conversion increases with increasing of adsorbent-catalyst heating rate.DOI: http://dx.doi.org/10.5755/j01.ms.19.1.3832

  19. Bioavailability of cadmium adsorbed on various oxides minerals to wetland plant species Phragmites australis

    International Nuclear Information System (INIS)

    Wang He; Jia Yongfeng; Wang Shaofeng; Zhu Huijie; Wu Xing

    2009-01-01

    The bioavailability of heavy metals strongly depends on their speciation in the environment. The effect of different chemical speciations of cadmium ions (i.e. adsorbed on different oxide minerals) on its bioavailability to wetland plant Phragmites australis was studied. Goethite, magnetite, gibbsite, alumina, and manganese oxide were chosen as representatives of metal (hydr)oxides commonly present in sediment. The cultivar system with Hoagland solution as nutrition supply, and single metal oxide with adsorbed Cd as contaminant was applied to study Cd accumulation by P. australis. The bioaccumulation degree in root after the 45-day treatment followed the order: Al(OH) 3 > Al 2 O 3 > Fe 3 O 4 > MnO 2 > FeOOH. The concentration of Cd in stem and leaf followed a similar order although it was considerably lower than that in root. Low-molecular-weight organic acids (LMWOAs), acetic acid, malic acid and citric acid were used to evaluate the desorbability of Cd from different oxides, which can be indicative of Cd-oxide bonding strength and Cd bioavailability. Desorption of Cd by acetic acid and malic acid followed the order: Al(OH) 3 > Fe 3 O 4 > Al 2 O 3 > FeOOH > MnO 2 , while by citric acid: Al(OH) 3 ≥ Al 2 O 3 > Fe 3 O 4 > FeOOH > MnO 2 . This was consistent with the Cd accumulation degree in the plant. Cd adsorbed on Al(OH) 3 was the most easily desorbable species and most bioavailable to P. australis among the oxide minerals, whereas MnO 2 adsorbed Cd was least desorbable by LMWOAs hence constituted the least bioavailable Cd species adsorbed on the oxide minerals.

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

    Science.gov (United States)

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

    2013-07-01

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

  1. Toluene and acetaldehyde removal from air on to graphene-based adsorbents with microsized pores.

    Science.gov (United States)

    Kim, Ji Min; Kim, Ji Hoon; Lee, Chang Yeon; Jerng, Dong Wook; Ahn, Ho Seon

    2018-02-15

    Volatile organic compound (VOC) gases can cause harm to the human body with exposure over the long term even at very low concentrations (ppmv levels); thus, effective absorbents for VOC gas removal are an important issue. In this study, accordingly, graphene-based adsorbents with microsized pores were used as adsorbents to remove toluene and acetaldehyde gases at low concentrations (30ppm). Sufficient amounts of the adsorbents were prepared for use on filters and were loaded uniformly at 0.1-0.5g on a 50×50mm 2 area, to evaluate their adsorption features with low gas concentrations. The morphology and chemical composition of the adsorbents were characterized using scanning electron microscopy, N 2 adsorption-desorption isotherms, X-ray photoelectron spectroscopy, and Raman spectroscopy. Microwave irradiation and heat treatment near 800°C under KOH activation resulted in enlargement of the pristine graphene surface and its specific surface area; maximum volume capacities of 3510m 3 /g and 630m 3 /g were observed for toluene and acetaldehyde gas. The high removal efficiency for toluene (98%) versus acetaldehyde (30%) gas was attributed to π-π interactions between the pristine graphene surface and toluene molecules. Copyright © 2017 Elsevier B.V. All rights reserved.

  2. Development and characterization of nifedipine-amino methacrylate copolymer solid dispersion powders with various adsorbents

    Directory of Open Access Journals (Sweden)

    Yotsanan Weerapol

    2017-07-01

    Full Text Available Solid dispersions of nifedipine (NDP, a poorly water-soluble drug, and amino methacrylate copolymer (AMCP with aid of adsorbent, that is, fumed silica, talcum, calcium carbonate, titanium dioxide, and mesoporous silica from rice husks (SRH, were prepared by solvent method. The physicochemical properties of solid dispersions, compared to their physical mixtures, were determined using powder X-ray diffractometry (PXRD and differential scanning calorimetry (DSC. The surface morphology of the prepared solid dispersions was examined by scanning electron microscopy (SEM. The dissolution of NDP from solid dispersions was compared to NDP powders. The effect of adsorbent type on NDP dissolution was also examined. The dissolution of NDP increased with the ratio of NDP:AMCP:adsorbent of 1:4:1 when compared to the other formulations. As indicated from PXRD patterns, DSC thermograms and SEM images, NDP was molecularly dispersed within polymer carrier or in an amorphous form, which confirmed the better dissolution of solid dispersions. Solid dispersions containing SRH provided the highest NDP dissolution, due to a porous nature of SRH, allowing dissolved drug to fill in the pores and consequently dissolve in the medium. The results suggested that solid dispersions containing adsorbents (SRH in particular demonstrated improved dissolution of poorly water-soluble drug when compared to NDP powder.

  3. A review on applicability of naturally available adsorbents for the removal of hazardous dyes from aqueous waste.

    Science.gov (United States)

    Sharma, Pankaj; Kaur, Harleen; Sharma, Monika; Sahore, Vishal

    2011-12-01

    The effluent water of many industries, such as textiles, leather, paper, printing, cosmetics, etc., contains large amount of hazardous dyes. There is huge number of treatment processes as well as adsorbent which are available for the processing of this effluent water-containing dye content. The applicability of naturally available low cast and eco-friendly adsorbents, for the removal of hazardous dyes from aqueous waste by adsorption treatment, has been reviewed. In this review paper, we have provided a compiled list of low-cost, easily available, safe to handle, and easy-to-dispose-off adsorbents. These adsorbents have been classified into five different categories on the basis of their state of availability: (1) waste materials from agriculture and industry, (2) fruit waste, (3) plant waste, (4) natural inorganic materials, and (5) bioadsorbents. Some of the treated adsorbents have shown good adsorption capacities for methylene blue, congo red, crystal violet, rhodamine B, basic red, etc., but this adsorption process is highly pH dependent, and the pH of the medium plays an important role in the treatment process. Thus, in this review paper, we have made some efforts to discuss the role of pH in the treatment of wastewater.

  4. Some economic considerations for a pilot plant based on the adsorber loop concept

    International Nuclear Information System (INIS)

    Koske, P.H.; Ohlrogge, K.; Jager, W.

    1984-01-01

    Some first order estimates about the production costs of seawater uranium are presented on the basis of a pilot plant with a capacity of about 100 t uranium per year. The plant is assumed to be operating at high seas using the ''adsorber loop concept'' for the contact between seawater and adsorber granulate. The effects of some process relevant components and parameters are discussed with regard to their contribution to the production costs and in order to analyse their cost-cutting potential. (orig.) [de

  5. Study of composite adsorbent synthesis and characterization for the removal of Cs in the high-salt and high-radioactive wastewater

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Jimin; Lee, Keun Young; Kim, Kwang Wook; Lee, Eil Hee; Chung, Dong Yong; Moon, Jei Kwon [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of); Hyun, Jae Hyuk [Chungnam National University, Daejeon (Korea, Republic of)

    2017-03-15

    For the removal of cesium (Cs) from high radioactive/high salt-laden liquid waste, this study synthesized a highly efficient composite adsorbent (potassium cobalt ferrocyanide (PCFC)-loaded chabazite (CHA)) and evaluated its applicability. The composite adsorbent used CHA, which could accommodate Cs as well as other molecules, as a supporting material and was synthesized by immobilizing the PCFC in the pores of CHA through stepwise impregnation/precipitation with CoCl{sub 2} and K{sub 4}Fe (CN){sub 6} solutions. When CHA, with average particle size of more than 10 μm, is used in synthesizing the composite adsorbent, the PCFC particles were immobilized in a stable form. Also, the physical stability of the composite adsorbent was improved by optimizing the washing methodology to increase the purity of the composite adsorbent during the synthesis. The composite adsorbent obtained from the optimal synthesis showed a high adsorption rate of Cs in both fresh water (salt-free condition) and seawater (high-salt condition), and had a relatively high value of distribution coefficient (larger than 10{sup 4} mL·g{sup -1}) regardless of the salt concentration. Therefore, the composite adsorbent synthesized in this study is an optimized material considering both the high selectivity of PCFC on Cs and the physical stability of CHA. It is proved that this composite adsorbent can remove rapidly Cs contained in high radioactive/high salt-laden liquid waste with high efficiency.

  6. Mathematical Modelling of Nitrate Removal from Water Using a Submerged Membrane Adsorption Hybrid System with Four Adsorbents

    Directory of Open Access Journals (Sweden)

    Mahatheva Kalaruban

    2018-01-01

    Full Text Available Excessive concentrations of nitrate in ground water are known to cause human health hazards. A submerged membrane adsorption hybrid system that includes a microfilter membrane and four different adsorbents (Dowex 21K XLT ion exchange resin (Dowex, Fe-coated Dowex, amine-grafted (AG corn cob and AG coconut copra operated at four different fluxes was used to continuously remove nitrate. The experimental data obtained in this study was simulated mathematically with a homogeneous surface diffusion model that incorporated membrane packing density and membrane correlation coefficient, and applied the concept of continuous flow stirred tank reactor. The model fit with experimental data was good. The surface diffusion coefficient was constant for all adsorbents and for all fluxes. The mass transfer coefficient increased with flux for all adsorbents and generally increased with the adsorption capacity of the adsorbents.

  7. Development of Highly Efficient Grafting Technique and Synthesis of Natural Polymer-Based Graft Adsorbent

    Energy Technology Data Exchange (ETDEWEB)

    Ueki, Y; Seko, N; Tamada, M [Japan Atomic Energy Agency, Quantum Beam Science Directorate, Takasaki (Japan)

    2012-09-15

    In the framework of the CRP, Japan has focused on the development of fibrous adsorbents for removal of toxic metal ions and recovery of significant metal ions from industrial wastewater and streaming water. Graft polymerization was carried out by using gamma irradiation facility and electron beam accelerator. Emulsion grafting is a novel topic for synthesis of metal ion adsorbents which are prepared from fibrous trunk polymers such as polyethylene fibre and biodegradable nonwoven fabrics. The emulsion grafting, where monomer micelles are dispersed in water in the presence of surfactant, is a highly efficient and economic grafting technique as compared to general organic solvent system. The resultant cotton-based adsorbent has high adsorption efficiency and high adsorption capacity for Hg, besides, it is biodegradable. Polylactic acid can also be used as a trunk material for the grafting. (author)

  8. Hexadimethrine-montmorillonite nanocomposite: Characterization and application as a pesticide adsorbent

    International Nuclear Information System (INIS)

    Gámiz, B.; Hermosín, M.C.; Cornejo, J.; Celis, R.

    2015-01-01

    Graphical abstract: - Highlights: • Characterization of hexadimethrine-montmorillonite nanocomposite was appraised. • Comparative studies with traditional HDTMA-montmorillonite were performed. • We investigated the pesticide adsorption mechanisms displayed by the nanocomposites. • Hexadimethrine-nanocomposite showed selective affinity for anionic pesticides. - Abstract: The goal of this work was to prepare and characterize a novel functional material by the modification of SAz-1 montmorillonite with the cationic polymer hexadimethrine (SA-HEXAD), and to explore the potential use of this nanocomposite as a pesticide adsorbent. Comparative preparation and characterization with the well-known hexadecyltrimethylammonium-modified SAz-1 montmorillonite (SA-HDTMA) was also assessed. The characterization was performed by elemental analysis, X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR), physisorption of N 2 , scanning electron microscopy (SEM) and Z potential measurements. The characterization and adsorption experiments showed that the extent of pesticide adsorption was markedly subjected to the structure and features of the surface of each organo-clay and also to the nature of the considered pesticide. SA-HEXAD displayed a high affinity for anionic pesticides which, presumably, were adsorbed by electrostatic attraction on positively-charged ammonium groups of the polymer not directly interacting with the clay. In contrast, SA-HDTMA displayed great adsorption of both uncharged and anionic pesticides with predominance of hydrophobic interactions. This work provided information about the surface properties of a new organic–inorganic nanohybrid material, SA-HEXAD, and its potential as an adsorbent for the removal of anionic organic pollutants from aqueous solutions

  9. Structural and electronic properties of the adsorbed and defected Cu nanowires: A density-functional theory study

    Energy Technology Data Exchange (ETDEWEB)

    Duan, Ying-Ni [College of Physics and Information Technology, Shaanxi Normal University, Xian 710062, Shaanxi (China); Department of Medical Engineering and Technology, Xinjiang Medical University, Urumqi 830011, Xinjiang (China); Zhang, Jian-Min, E-mail: jianm_zhang@yahoo.com [College of Physics and Information Technology, Shaanxi Normal University, Xian 710062, Shaanxi (China); Fan, Xiao-Xi [Department of Medical Engineering and Technology, Xinjiang Medical University, Urumqi 830011, Xinjiang (China); Xu, Ke-Wei [College of Physics and Mechanical and Electronic Engineering, Xian University of Arts and Science, Xian 710065, Shaanxi (China)

    2014-12-01

    Using first-principles calculations based on density-functional theory, we systematically investigate the influence of adsorbates (CO molecule and O atom) and defects (adsorb one extra Cu atom and monovacancy) on the structural and electronic properties of Cu{sub 5-1}NW and Cu{sub 6-1}NW. For both nanowires, CO molecule prefers to adsorb on the top site, while O atom prefers to adsorb on the center site. The hybridization between the CO and Cu states is dominated by the donation–backdonation process, which leads to the formation of bonding/antibonding pairs, 5σ{sub b}/5σ{sub a} and 2π{sub b}{sup ⁎}/2π{sub a}{sup ⁎}. The larger adsorption energies, larger charge transfers to O adatom and larger decrease in quantum conductance 3G{sub 0} for an O atom adsorbed on the Cu{sub 5-1}NW and Cu{sub 6-1}NW show both Cu{sub 5-1}NW and Cu{sub 6-1}NW can be used as an O sensor. Furthermore, the decrease in quantum conductance 1G{sub 0} for a CO molecule adsorbed on the Cu{sub 6-1}NW also shows the Cu{sub 6-1}NW can be used to detect CO molecule. So we expect these results may have implications for CuNW based chemical sensing. High adsorption energy of one extra Cu atom and relatively low formation energy of a monovacancy suggest that these two types of defects are likely to occur in the fabrication of CuNWs. One extra Cu atom does not decrease the quantum conductance, while a Cu monovacancy leads to a drop of the quantum conductance.

  10. Comparative analysis of the efficiencies of two low cost adsorbents ...

    African Journals Online (AJOL)

    ISHIOMA

    tanning, metallurgical operation and manufacturing have led to the release ... pulmonary fibrosis and inhibit many enzymatic functions. (Liphadzi ... sector is a low cost adsorbent for heavy metal but has ... as its economic value is less. The aim ...

  11. Utilization of fish bone as adsorbent of Fe3+ ion by controllable removal of its carbonaceous component

    Science.gov (United States)

    Nurhadi, M.; Kusumawardani, R.; Widiyowati, I. I.; Wirhanuddin; Nur, H.

    2018-05-01

    The performance of fish bone to adsorb Fe3+ ion in solution was studied. Powdered fish bone and carbonized fish bone were used as adsorbent. All absorbents were characterized by X-ray diffraction (XRD), IR spectroscopy, nitrogen adsorption, scanning electron microscopy (SEM) and TG analysis. Powdered fish bone and carbonized fish bone were effective as adsorbent for removing Fe3+ ion in solution. The metal adsorptions of Fe3+ ion were 94 and 98% for powdered fish bone and fish bone which carbonized at 400 and 500 °C.

  12. Influence of solvent on the infared spectrum of carbon monoxide adsorbed on platinum electrodes

    OpenAIRE

    Feltovich, Susanne D.

    1993-01-01

    The behavior of adsorbed carbon monoxide on platinum was studied using potential difference infrared spectroscopy. Three solvents and three electrolytes were chosen, and data gathered at both high and low adsorbate coverages. The rate of change of IR peak position with applied potential, the Stark tuning rate, was used as an indicator of the local electric field strength at the interface. It was determined that neither solvated cation size nor bulk dielectric constant accoun...

  13. Determination of Cr and Cd concentration adsorbed by chicken feathers

    International Nuclear Information System (INIS)

    Lopez M, A.; Cuapio O, L.A.; Cardenas P, S.; Balcazar, M.; Jauregui, V.; Bonilla P, A.

    2008-01-01

    In this work the results of the samples analysis of chicken feathers are presented, used as adsorber of the heavy metals Cd and Cr present in water solutions with well-known concentrations of these metals. It was used the Neutron Activation Analysis technique (AAN), using the TRIGA Mark-III reactor of the Nuclear Center of Mexico. The obtained results they show the advantages of having a versatile installation for the analysis of this type of samples. By means of the analysis of the results, it was determined the feasibility of using chicken feathers like adsorber of these metals present in polluted waters, additionally, it was detected the presence of others polluting elements in the inputs to prepare the reference solutions as well as in the processes, so much of preparation of the feathers like of the metals adsorption. (Author)

  14. Synthesis of low-cost adsorbent from rice bran for the removal of reactive dye based on the response surface methodology

    Science.gov (United States)

    Hong, Gui-Bing; Wang, Yi-Kai

    2017-11-01

    Rice bran is a major by-product of the rice milling industry and is abundant in Taiwan. This study proposed a simple method for modifying rice bran to make it a low-cost adsorbent to remove reactive blue 4 (RB4) from aqueous solutions. The effects of independent variables such as dye concentration (100-500 ppm), adsorbent dosage (20-120 mg) and temperature (30-60 °C) on the dye adsorption capacity of the modified rice bran adsorbent were investigated by using the response surface methodology (RSM). The results showed that the dye maximum adsorption capacity of the modified rice bran adsorbent was 151.3 mg g-1 with respect to a dye concentration of 500 ppm, adsorbent dosage of 65.36 mg, and temperature of 60 °C. The adsorption kinetics data followed the pseudo-second-order kinetic model, and the isotherm data fit the Langmuir isotherm model well. The maximum monolayer adsorption capacity was 178.57-185.19 mg g-1, which was comparable to that of other agricultural waste adsorbents used to remove RB4 from aqueous solutions in the literature. The thermodynamics analysis results indicated that the adsorption of RB4 onto the modified rice bran adsorbent is an endothermic, spontaneous monolayer adsorption that occurs through a physical process.

  15. A new polymeric adsorbent developing for uranium recovering and richment from aqueous media

    International Nuclear Information System (INIS)

    Gueler, H.; Aycik, G. A.; Sahiner, N.; Gueven, O.

    1997-01-01

    Using adsorbents is thought to be the most effective method for recovering the low concentrations of uranium in the aqueous media because of their fast and selective uptake of uranium, a sufficient adsorption capacity and high physical and chemical stability against the media. In this study, a new polymeric adsorbent bearing both hydrophilic groups providing swelling in water and amidoxime groups for chelating with uranyl ions (UO 2 ''2+) has been developed and its adsorptive ability for uranium from aqueous media has been investigated. The polymers obtained by irradiating the solution of polyethylene glycol (PEG) in acrylonitrile (AN) are defined as Interpenetrating Polymer Networks (IPNs) and the adsorbent has been obtained by applying the amidoximation reaction to the IPNs with a conversion of % 60 approximately. Kinetics of the conversion reaction of nitrile (CN) group to amidoxime (HONCNH 2 ) group has been studied by reacting with hydroxylamine (NH 2 OH) solution at a molar ratio of NH 2 OH/CN=1.25 in aqueous media at different temperatures, 30,40,50''0C, for 3-4 days. The degree of amidoximation was determined by UO 2 ''2+ ion adsorption and FTIR spectrometer and the UO 2 ''2+ ion adsorption values were found by both UV and gamma spectrometry and also by gravimetry. It was found that the polymeric adsorbent has a very high adsorption ability for uranium (∼ 540 mg U/g IPN/day)

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

    International Nuclear Information System (INIS)

    Esen, K.; Donat, R.; Cetisli, H.; Aytas, S.

    2006-01-01

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

  17. Theoretical investigation of the use of nanocages with an adsorbed halogen atom as anode materials in metal-ion batteries.

    Science.gov (United States)

    Razavi, Razieh; Abrishamifar, Seyyed Milad; Rajaei, Gholamreza Ebrahimzadeh; Kahkha, Mohammad Reza Rezaei; Najafi, Meysam

    2018-02-21

    The applicability of C 44 , B 22 N 22 , Ge 44 , and Al 22 P 22 nanocages, as well as variants of those nanocages with an adsorbed halogen atom, as high-performance anode materials in Li-ion, Na-ion, and K-ion batteries was investigated theoretically via density functional theory. The results obtained indicate that, among the nanocages with no adsorbed halogen atom, Al 22 P 22 would be the best candidate for a novel anode material for use in metal-ion batteries. Calculations also suggest that K-ion batteries which utilize these nanocages as anode materials would give better performance and would yield higher cell voltages than the corresponding Li-ion and Na-ion batteries with nanocage-based anodes. Also, the results for the nanocages with an adsorbed halogen atom imply that employing them as anode materials would lead to higher cell voltages and better metal-ion battery performance than if the nanocages with no adsorbed halogen atom were to be used as anode materials instead. Results further implied that nanocages with an adsorbed F atom would give higher cell voltages and better battery performance than nanocages with an adsorbed Cl or Br atom. We were ultimately able to conclude that a K-ion battery that utilized Al 21 P 22 with an adsorbed F atom as its anode material would afford the best metal-ion battery performance; we therefore propose this as a novel highly efficient metal-ion battery. Graphical abstract The results of a theoretical investigation indicated that Al 22 P 22 is a better candidate for a high-performance anode material in metal-ion batteries than Ge 44 is. Calculations also showed that K-ion batteries with nanocage-based anodes would produce higher cell voltages and perform better than the equivalent Li-ion and Na-ion batteries with nanocage-based anodes, and that anodes based on nanocages with an adsorbed F atom would perform better than anodes based on nanocages with an adsorbed Cl or Br atom.

  18. Regeneration of Waste Edible Oil by the Use of Virgin and Calcined Magnesium Hydroxide as Adsorbents.

    Science.gov (United States)

    Ogata, Fumihiko; Kawasaki, Naohito

    2016-01-01

    In this study, we prepared virgin (S, L) and calcined (S-380, S-1000, L-380, L-1000) magnesium hydroxide for regeneration of waste edible oil. Deterioration of soybean oil, rapeseed oil, and olive oil was achieved by heat and aeration treatment. The properties of the different adsorbents were investigated using specific surface area measurements, scanning electron microscopy, X-ray diffraction analysis, thermogravimetric-differential thermal analysis, and surface pH measurement. Moreover, the relationship between the changes in acid value (AV) and carbonyl value (CV) and the adsorbent properties were evaluated. The specific surface areas of S-380 and L-380 were greater than that of other adsorbents. In addition, the XRD results show that S-380 and L-380 contain both magnesium hydroxide and magnesium oxide structures. The decreases in AV and CV using S-380 and L-380 were greater than achieved using other adsorbents. The correlation coefficients between the decrease in AV and CV and specific surface area were 0.947 for soybean oil, 0.649 for rapeseed oil, and 0.773 for olive oil, respectively. The results obtained in this study suggest that a physical property of the adsorbent, namely specific surface area, was primarily responsible for the observed decreases in AV and CV. Overall, the results suggest that S-380 and L-380 are useful for the regeneration of waste edible oil.

  19. Using Adsorption Isotherm Studies to Determine Crosslinked Polymeric Adsorbent Performance in Heavy Metals Removal from Water

    Directory of Open Access Journals (Sweden)

    Nasrin Sheikh

    2015-01-01

    Full Text Available Polymeric adsorbents are useful tools for removing heavy metals from aqueous solutions. Adsorption models are efficient tools for accurate prediction and evaluation of the practical adsorption process in real situation. In this study, the two isotherms of Langmuir and Dubinin-Radushkevich models were employed to investigate the absorption performance of chitosan, PVA, and chitosan/PVA blend (with a weight ratio of 1:1 in the removal of Mn (II and Ni (II from aqueous solutions. The PVA adsorbent was crosslinked by both chemical and radiation methods while the others were crosslinked only chemically due to Chitosan’s lack of resistance to radiation. The results showed that the Langmuir model fitted the experimental data better than the Dubinin-Radushkevich one for both metals. The maximum adsorption capacity (qmax of the Langmuir model showed that the PVA/Chitosan adsorbent had the best adsorption compared to other adsorbents, with 52.63 mg/g for Ni and 30.30 mg/g for Mn (evidently more Ni was absorbed than Mn. Also, maximum adsorption by the chemically crosslinked PVA was 38.46 mg/g for Ni and 19.23 mg/g for Mn, which exhibits a higher level than adsorption by the radiation crosslinked PVA The results indicate that absorption capacity depends on the type of adsorbed metal, absorbent structure, and the crosslinking method employed.

  20. Performance evaluation of oxygen adsorbents using negative corona discharge–ion mobility spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Azadkish, Kamal; Jafari, Mohammad T., E-mail: jafari@cc.iut.ac.ir; Ghaziaskar, Hassan S.

    2017-02-08

    Trace amounts of oxygen was determined using negative corona discharge as an ionization source for ion mobility spectrometry. A point-in-cylinder geometry with novel design was used to establish the corona discharge without interferences of negative ions such as NO{sub X}{sup −}. The desirable background spectrum shows only electrons peak, providing the instrument capable of trace analysis of oxygen in gaseous samples. The limit of detection and linear dynamic range with high coefficient of determination (r{sup 2} = 0.9997), were obtained for oxygen as 8.5 and 28–14204 ppm, respectively. The relative standard deviations of the method for intraday and interday were obtained 4 and 11%, respectively. The satisfactory results revealed the ability of the negative corona discharge ion mobility spectrometry for investigating the performance of synthesized oxygen adsorbents in nitrogen streams. Two oxygen scavengers of MnO and Cu powder were prepared and the optimum temperature of the reactor containing MnO and Cu powder were obtained as 180 and 230 °C, respectively. Due to higher lifetime of copper powder, it was selected as the oxygen scavenger and some parameters such as: the type of adsorbent support, the size of adsorbent particles, and the amount of copper were studied for preparation of more efficient oxygen adsorbent. - Highlights: • Analysis of oxygen using negative corona discharge-ion mobility spectrometry was investigated for the first time. • Novel designed point-in-cylinder geometry was used to establish the corona discharge without interferences of negative ions. • The method was utilized to evaluate the performance of some synthesized oxygen scavengers.

  1. Factor Affecting Textile Dye Removal Using Adsorbent From Activated Carbon: A Review

    Directory of Open Access Journals (Sweden)

    Mohammad Razi Mohd Adib

    2017-01-01

    Full Text Available Industrial company such as textile, leather, cosmetics, paper and plastic generated wastewater containing large amount of dye colour. The removal of dye materials are importance as the presence of this kind of pollutant influence the quality of water and makes it aesthetically unpleasant. As their chemical structures are complicated, it is difficult to treat dyes with municipal waste treatment operations. Even a small quantity of dye does cause high visibility and undesirability. There have been various treatment technique reviewed for the removal of dye in wastewater. However, these treatment process has made it to another expensive treatment method. This review focus on the application of adsorbent in dye removal from textile wastewater as the most economical and effective method, adsorption has become the most preferred method to remove dye. The review provides literature information about different basis materials used to produce activated carbon like agricultural waste and industrial waste as well as the operational parameters factors in term of contact time, adsorbent dosage, pH solution and initial dye concentration that will affect the process in removing textile dye. This review approach the low cost and environmental friendly adsorbent for replacing conventional activated carbon.

  2. Investigation of adsorption of Rhodamine B onto a natural adsorbent Argemone mexicana.

    Science.gov (United States)

    Khamparia, Shraddha; Jaspal, Dipika

    2016-12-01

    The present study aims at exploring the potential of the seeds of a tropical weed, Argemone mexicana (AM), for the removal of a toxic xanthene textile dye, Rhodamine B (RHB), from waste water. Impact of pH, adsorbent dosage, particle size, contact time and dye concentration have been assessed during adsorption. The weed has been well characterized by several latest techniques thereby providing an indepth information of the mechanism during adsorption. About 80% removal has been attained with 0.06 g of adsorbent over the studied system. Thermodynamic and kinetic studies, followed by second order kinetic model, directed towards the endothermic nature of adsorption. The results obtained from batch experiments were modelled using Langmuir and Freundlich isotherm and were analysed on the basis of R 2 and six error functions for selection of appropriate model. Langmuir isotherm was found to be best fitted to the experimental data with high values of R 2 and lower values of error functions. Adsorption study revealed the affinity of AM seeds for the dye ions present in waste water, introducing a novel adsorbent in field of waste water treatment. Copyright © 2016 Elsevier Ltd. All rights reserved.

  3. STATISTICAL INVESTIGATION OF ADSORPTION OF TWO REACTIVE TEXTILE DYES BY VARIOUS ADSORBENTS

    Directory of Open Access Journals (Sweden)

    Ümmühan DANIŞ

    2002-03-01

    Full Text Available Textile industry, in which uses the dyestuffs containing coloured and complex chemical compounds, is both water consumer and water pollutant. The removal of these compounds from the wastewaters is one of the most important problems in the textile industry. In this study, the adsorption of two reactive dyes (Red Px and Yellow P onto Aşkale and Balkaya lignites, Bensan clay and powdered active carbon (PAC from aqueous solution was statistically investigated. The adsorption time, dye concentration, solid/liquid ratio and mixing rate were chosen as parameters. The effects of these parameters on the amount of dye adsorbed by the adsorbents were determined. The results obtained have been statistically evaluated by using the stepwise method and SPSS Sortware version (9.1. The experimental observations and statistical evaluations shown that the effective parameters on the adsorption are equilibrium dye concentration and solid/liquid ratio. It was found that the adsorptive behaviours of both lignites and clay are similar to each other, but powdered active carbon displays different adsorptive behaviour. Finally, the empirical equations showing the relation between amount of dye adsorbed and the effective parameters were developed.

  4. Storage in pressurized cylinders of Kr adsorbed on activated carbon. Fundamental principles

    International Nuclear Information System (INIS)

    Henrion, P.N.; Greff, J.F. de; Claes, W.; Leurs, A.

    1979-01-01

    Pressure of a few kg/cm 2 cause considerable adsorption of krypton on charcoal. In presence of this adsorbent, the aspects of krypton storage in a pressurized cylinder are modified in such a way that, eventually, a simplified engineered storage can be based on this procedure. As fission krypton generates heat and since the amount adsorbed is a function of temperature and pressure, there is no easy way of assessing the value of this concept. The purpose of this study was therefore to review the types of charcoal commercially available to examine their properties as adsorbents, as well as the thermal conductivity and the packing efficiency obtainable in beds made of these materials. The ways in which data are measured or estimated are explained in some detail. Heat transfer was evaluated by a simple mathematical model and, by means of selected values from the above data, realistic examples were treated, leading to explicit relationships between wall temperature, pressure and useful krypton load. Influence of krypton specific activity ( 85 Kr dilution) was also examined. The pressure vessels diameter is however of fundamental importance. The authors strongly recommend the use of specially designed, light-weight, relatively narrow pressure cylinders

  5. First-principles studies on 3d transition metal atom adsorbed twin graphene

    Science.gov (United States)

    Li, Lele; Zhang, Hong; Cheng, Xinlu; Miyamoto, Yoshiyuki

    2018-05-01

    Twin graphene is a new two-dimensional semiconducting carbon allotrope which is proposed recently. The structural, magnetic and electronic properties are investigated for 3d transition metal (TM) atom adsorbed twin graphene by means of GGA+U calculations. The results show most of single 3d transition metal atom except Zn can make twin graphene magnetization. The adsorption of single TM atom can also make the twin graphene systems turn to half metal (V adsorption), half-semiconductor (Fe adsorption) or metal (Sc, Cr, Mn, Co and Cu adsorption). The semiconducting nature still exists for Ti, Ni and Zn adsorption. All the 3d TM adatoms belong to n-type doping for transferring charge to the neighboring C atoms and have strong covalent bond with these C atoms. The influence of Hubbard U value on half-metallic V adsorbed system is also considered. As the U increases, the system can gradually transform from metal to half metal and metal. The effect of the coverage is investigated for two TM atoms (Sc-Fe) adsorption, too. We can know TM atoms adsorbed twin graphene have potentials to be spintronic device and nanomagnets from the results.

  6. Coconut Husk Adsorbent for the Removal of Methylene Blue Dye from Wastewater

    Directory of Open Access Journals (Sweden)

    Hasfalina Che bt Man

    2015-03-01

    Full Text Available A study to assess the efficiency of coconut husks (CHs in removing methylene blue (MB dye from wastewaters in Malaysia was carried out. A fixed bed column adsorber was set up using flow rates of 40 and 80 mL/min, and the adsorbent (CH was prepared using the base treatment method with NaOH as activating agent. Three different column bed depths (10, 20, and 25 cm and unit weights of adsorbent (103, 213, and 260 g were used. Two models, the bed depth service time (BDST and Thomas models, were used to validate the adsorption capacity results and breakthrough curve. Changing the bed depth from 20 to 25 cm did not result in a significant change in adsorption capacity, therefore a 20-cm bed depth is recommended as the most efficient. Similarly, adsorption capacity increased as flow rates increased from 40 to 80 mL/min, indicating that a flow rate of 80 mL/min yielded optimum efficiency. The two models also provided predictions with good fits of the bed depth effect, the adsorption capacity, and the breakthrough curve of CH for MB removal.

  7. Molecular Insights into the pH-Dependent Adsorption and Removal of Ionizable Antibiotic Oxytetracycline by Adsorbent Cyclodextrin Polymers

    Science.gov (United States)

    Zhang, Yu; Cai, Xiyun; Xiong, Weina; Jiang, Hao; Zhao, Haitong; Yang, Xianhai; Li, Chao; Fu, Zhiqiang; Chen, Jingwen

    2014-01-01

    Effects of pH on adsorption and removal efficiency of ionizable organic compounds (IOCs) by environmental adsorbents are an area of debate, because of its dual mediation towards adsorbents and adsorbate. Here, we probe the pH-dependent adsorption of ionizable antibiotic oxytetracycline (comprising OTCH2 +, OTCH±, OTC−, and OTC2−) onto cyclodextrin polymers (CDPs) with the nature of molecular recognition and pH inertness. OTCH± commonly has high adsorption affinity, OTC− exhibits moderate affinity, and the other two species have negligible affinity. These species are evidenced to selectively interact with structural units (e.g., CD cavity, pore channel, and network) of the polymers and thus immobilized onto the adsorbents to different extents. The differences in adsorption affinity and mechanisms of the species account for the pH-dependent adsorption of OTC. The mathematical equations are derived from the multiple linear regression (MLR) analysis of quantitatively relating adsorption affinity of OTC at varying pH to adsorbent properties. A combination of the MLR analysis for OTC and molecular recognition of adsorption of the species illustrates the nature of the pH-dependent adsorption of OTC. Based on this finding, γ-HP-CDP is chosen to adsorb and remove OTC at pH 5.0 and 7.0, showing high removal efficiency and strong resistance to the interference of coexisting components. PMID:24465975

  8. Adsorbate-driven cooling of carbene-based molecular junctions

    Czech Academy of Sciences Publication Activity Database

    Foti, Giuseppe; Vázquez, Héctor

    2017-01-01

    Roč. 8, Oct (2017), s. 2060-2068 ISSN 2190-4286 R&D Projects: GA ČR GA15-19672S EU Projects: European Commission(XE) 702114 - HEATEXMOL Institutional support: RVO:68378271 Keywords : adsorbate * carbene * current-induced heating and cooling * molecular junction * vibrations Subject RIV: BM - Solid Matter Physics ; Magnetism OBOR OECD: Condensed matter physics (including formerly solid state physics, supercond.) Impact factor: 3.127, year: 2016

  9. Removal of radionuclides from acid mine waters by retention on adsorbing materials

    International Nuclear Information System (INIS)

    Nascimento, M.R.L.; Fukuma, H.T.; Costa da, W.C.; Quinelato, A.L.; Gomes, H.A.; Garcia, O.Jr.

    2006-01-01

    This study proposes a method for decontamination of acid drainage water from a uranium mine, as an alternative process to lime treatment. The research embodied the recovery of uranium with an ion-exchange resin, treatment of effluent resin with lime, or with inorganic adsorbents and biosorbents. The uranium decontamination level using the resin process was 94% and allowed the recovery of this element as a commercial product. Among the inorganic adsorbents studied, phosphogypsum was effective for 226 Ra, 228 Ra, and 210 Pb removal. Among the biosorbents, Sargassum sp. was superior in relation to its specific capacity to accumulate and remove 226 Ra. (author)

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

    Science.gov (United States)

    Marangoni, Rafael; Mikowski, Alexandre; Wypych, Fernando

    2010-11-15

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

  11. Thermal effects of CO2 capture by solid adsorbents: some approaches by IR image processing

    International Nuclear Information System (INIS)

    Benevides Ferreira, J.F.; Pradere, C.; Batsale, J.C.; Jolly, J.; Pavageau, B.; Le Bourdon, G.; Mascetti, J.; Servant, L.

    2013-01-01

    Thanks to infrared thermography, we have studied the mechanisms of CO 2 capture by solid adsorbents (CO 2 capture via gas adsorption on various types of porous substrates) to better understand the physico-chemical mechanisms that control CO 2 -surface interactions. In order to develop in the future an efficient process for post-combustion CO 2 capture, it is necessary to quantify the energy of adsorption of the gas on the adsorbent (exothermic process). The released heat (heat of adsorption) is a key parameter for the choice of materials and for the design of capture processes. Infrared thermography is used, at first approach, to detect the temperature fields on a thin-layer of adsorbent during CO 2 adsorption. An analytical heat transfer model was developed to evaluate the adsorption heat flux and to estimate, via an inverse technique, the heat of adsorption. The main originality of our method is to estimate heat losses directly from the heat generated during the adsorption process. Then, the estimated heat loss is taken for an a posteriori calculation of the adsorption heat flux. Finally, the heat of adsorption may be estimated. The interest in using infrared thermography is also its ability to quickly change the experimental setup, for example, to switch from the adsorbent thin-layer to the adsorbent bed configuration. We present the first results tempting to link the thin-layer data to the propagation speed of the thermal front in a milli-fluidics adsorption bed, also observed by IR thermography. (authors)

  12. Removal of nickel from wastewater using an agricultural adsorbent

    African Journals Online (AJOL)

    2009-11-26

    Nov 26, 2009 ... qmax is the theoretical maximum adsorption capacity of the adsorbent (mg/g). KL is the Langmuir affinity constant (ℓ/mg). Ce is the supernatant equilibrium concentration of the system (mg/ℓ) (Febrianto et al., 2009). The Freundlich isotherm model can also be expressed in the linearised logarithmic form (Eq.

  13. 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

  14. Ultrasound aided in situ transesterification of crude palm oil adsorbed on spent bleaching clay

    International Nuclear Information System (INIS)

    Boey, Peng-Lim; Ganesan, Shangeetha; Maniam, Gaanty Pragas; Ali, Dafaalla Mohamed Hag

    2011-01-01

    Research highlights: → Crude palm oil adsorbed on spent bleaching clay converted to biodiesel. → Ultrasound dislodges adsorbed oil from spent bleaching clay into reaction mixture. → Co-solvents promotes miscibility of the reactants. -- Abstract: Adsorbed crude palm oil on spent bleaching clay (SBC) was in situ transesterified to methyl esters (biodiesel) by the aid of ultrasound and organic co-solvents (petroleum ether (PE) or ethyl methyl ketone (EMK)). The SBC under study was found to contain 24.2-27.0% of crude oil with free fatty acids (FFA) of 3.01% and moisture content of 0.29%. The optimized reaction conditions were as follows: methanol to oil molar ratio of 150:1; catalyst (KOH), 20%; reaction temperature, 60 ± 2 o C; reaction time, 2 h. Using PE as a co-solvent, highest conversion of 75.2% was achieved while 60% was recorded with EMK.

  15. Facile preparation of highly hydrophilic, recyclable high-performance polyimide adsorbents for the removal of heavy metal ions

    Energy Technology Data Exchange (ETDEWEB)

    Huang, Jieyang; Zheng, Yaxin; Luo, Longbo; Feng, Yan [State Key Laboratory of Polymer Material and Engineering, College of Polymer Science and Engineering, Sichuan University, Chengdu 610065 (China); Zhang, Chaoliang [State Key Laboratory of Oral Diseases, West China College of Stomatology, Sichuan University, Chengdu 610041 (China); Wang, Xu, E-mail: wx19861027@163.com [State Key Laboratory of Polymer Material and Engineering, College of Polymer Science and Engineering, Sichuan University, Chengdu 610065 (China); Liu, Xiangyang, E-mail: lxy6912@sina.com [State Key Laboratory of Polymer Material and Engineering, College of Polymer Science and Engineering, Sichuan University, Chengdu 610065 (China)

    2016-04-05

    Highlights: • High-performance polyimide was used as heavy metal adsorbents. • The contradiction between hydrophilicity and high performance of PI was solved. • Adsorption amount for Cu{sup 2+} of PI/silica was 77 times higher than that of PI. • The adsorption ability remained steady for more than 50 recycling processes. - Abstract: To obtain high-performance adsorbents that combine excellent adsorption ability, thermal stability, service life and recycling ability, polyimide (PI)/silica powders were prepared via a facile one-pot coprecipitation process. A benzimidazole unit was introduced into the PI backbone as the adsorption site. The benzimidazole unit induced more hydroxyls onto the silica, which provided hydrophilic sites for access by heavy metal ions. By comprehensively analyzing the effect of hydrophilcity, agglomeration, silica polycondensation, specific surface area and PI crystallinity, 10% was demonstrated to be the most proper feed silica content. The equilibrium adsorption amount (Q{sub e}) for Cu{sup 2+} of PI/silica adsorbents was 77 times higher than that of pure PI. Hydrogen chloride (HCl) was used as a desorbent for heavy metal ions and could be decomplexed with benzimidazole unit at around 300 °C, which was lower than the glass transition temperature of PI. The complexation and decomplexation process of HCl made PI/silica adsorbents recyclable, and the adsorption ability remained steady for more than 50 recycling processes. As PI/silica adsorbents possess excellent thermal stability, chemical resistance and radiation resistance and hydrophilicity, they have potential as superior recyclable adsorbents for collecting heavy metal ions from waste water in extreme environments.

  16. Bioavailability of cadmium adsorbed on various oxides minerals to wetland plant species Phragmites australis

    Energy Technology Data Exchange (ETDEWEB)

    Wang He, E-mail: he.wangworld@yahoo.com.cn [Key Laboratory of Terrestrial Ecological Process, Institute of Applied Ecology, Chinese Academy of Sciences, No. 72 Wenhua Road, Shenyang 110016 (China); Graduate School, Chinese Academy of Sciences, Beijing 100049 (China); Jia Yongfeng, E-mail: yongfeng.jia@iae.ac.cn [Key Laboratory of Terrestrial Ecological Process, Institute of Applied Ecology, Chinese Academy of Sciences, No. 72 Wenhua Road, Shenyang 110016 (China); Wang Shaofeng [Key Laboratory of Terrestrial Ecological Process, Institute of Applied Ecology, Chinese Academy of Sciences, No. 72 Wenhua Road, Shenyang 110016 (China); Zhu Huijie; Wu Xing [Key Laboratory of Terrestrial Ecological Process, Institute of Applied Ecology, Chinese Academy of Sciences, No. 72 Wenhua Road, Shenyang 110016 (China); Graduate School, Chinese Academy of Sciences, Beijing 100049 (China)

    2009-08-15

    The bioavailability of heavy metals strongly depends on their speciation in the environment. The effect of different chemical speciations of cadmium ions (i.e. adsorbed on different oxide minerals) on its bioavailability to wetland plant Phragmites australis was studied. Goethite, magnetite, gibbsite, alumina, and manganese oxide were chosen as representatives of metal (hydr)oxides commonly present in sediment. The cultivar system with Hoagland solution as nutrition supply, and single metal oxide with adsorbed Cd as contaminant was applied to study Cd accumulation by P. australis. The bioaccumulation degree in root after the 45-day treatment followed the order: Al(OH){sub 3} > Al{sub 2}O{sub 3} > Fe{sub 3}O{sub 4} > MnO{sub 2} > FeOOH. The concentration of Cd in stem and leaf followed a similar order although it was considerably lower than that in root. Low-molecular-weight organic acids (LMWOAs), acetic acid, malic acid and citric acid were used to evaluate the desorbability of Cd from different oxides, which can be indicative of Cd-oxide bonding strength and Cd bioavailability. Desorption of Cd by acetic acid and malic acid followed the order: Al(OH){sub 3} > Fe{sub 3}O{sub 4} > Al{sub 2}O{sub 3} > FeOOH > MnO{sub 2}, while by citric acid: Al(OH){sub 3} {>=} Al{sub 2}O{sub 3} > Fe{sub 3}O{sub 4} > FeOOH > MnO{sub 2}. This was consistent with the Cd accumulation degree in the plant. Cd adsorbed on Al(OH){sub 3} was the most easily desorbable species and most bioavailable to P. australis among the oxide minerals, whereas MnO{sub 2} adsorbed Cd was least desorbable by LMWOAs hence constituted the least bioavailable Cd species adsorbed on the oxide minerals.

  17. Dynamic study of adsorbers by a new gravimetric version of the Large Temperature Jump method

    International Nuclear Information System (INIS)

    Sapienza, Alessio; Santamaria, Salvatore; Frazzica, Andrea; Freni, Angelo; Aristov, Yuri I.

    2014-01-01

    Highlights: • We have carried out a dynamic study of adsorbers. • Activity performed by new gravimetric version of the Large Temperature Jump method. • The kinetics measurements have been carried out under real operating conditions. • Results can support the design of adsorbers for adsorption cooling systems. - Abstract: This paper presents a new experimental setup devoted to measure the ad-/desorption kinetics of an Ad-HEX (adsorbent + heat exchanger) under typical boundary conditions of an Adsorption Heat Transformer (AHT) as well as the results of the first test campaign carried out. The experimental apparatus can be considered as a gravimetric version of the known Large Temperature Jump method. In fact, the dynamic evolution of the uptake during the isobaric ad-/desorption stages is directly measured by a weighing system suitable to work in the range of 5–600 g of sample mass (adsorbent + HEX) with the accuracy ±0.1 g and the time response shorter than 0.1 s The experimental campaign was conducted on an Ad-HEX composed of granules of a commercial SAPO-34 adsorbent placed on a flat type aluminum HEX, under operating conditions reproducing two different thermodynamic cycles (T h = 90 °C, T e = 10 °C, T c = 30 and 35 °C), typical for adsorption air conditioning. The influence of the grain size (ranging from 0.350 to 2.5 mm) on the adsorption dynamics both in monolayer and multilayer configurations at variable and constant “heat transfer surface/adsorbent mass” ratios (S/m) was studied. The results showed that, for the Ad-HEX configurations tested, the adsorption dynamics can be properly described by a modified Linear Driving Force approach by the use of a single temperature-invariant characteristic time τ. The invariance of the specific cooling power was revealed when the S/m ratio was kept constant (S/m = 1.23 m 2 /kg). This ratio is found to be a useful parameter for both assessment of the dynamic perfection and optimization of various Ad

  18. Preparation of New Adsorbent Containing Hydroxamic Acid Groups by Electron Beam-Induced Grafting for Metal Ion Adsorption

    International Nuclear Information System (INIS)

    Suwanmala, Phiriyatorn; Hoshina, Hiroyuki; Seko, Noriaki; Tamada, Masao

    2007-08-01

    Full text: A new adsorbent containing hydroxamic acid groups was synthesized by electron beam-induced graft copolymerization of methyl acrylate (MA) onto nonwoven fabric composed of polyethylene-coated polypropylene fiber. Conversion of ester groups of the grafted copolymer into the hydroxamic groups was performed by treatment with an alkaline solution of hydroxylamine (HA). Adsorbent containing hydroxamic acid groups can adsorb 99% of UO2 2+ , 98% of V5+, 97% of Pb2+ and 96% of Al3+ at pH, 5, 4, 6, and 4, respectively, after coming into contact with 100 ppb metal solution for 24 h

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

    International Nuclear Information System (INIS)

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

    2015-01-01

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

  20. 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

  1. Nanostructured Fe2O3/Al2O3 Adsorbent for removal of As (V from water

    Directory of Open Access Journals (Sweden)

    Faranak Akhlaghian

    2017-04-01

    Full Text Available The presence of arsenate in drinking water causes adverse health effects including skin lesions, diabetes, cancer, damage to the nervous system, and cardiovascular diseases. Therefore, the removal of As (V from water is necessary. In this work, nanostructured adsorbent Fe2O3/Al2O3 was synthesized via the sol-gel method and applied to remove arsenate from polluted waters. First, the Fe2O3 load of the adsorbent was optimized. The Fe2O3/Al2O3 adsorbent was characterized by means of XRF, XRD, ASAP, and SEM techniques. The effects of the operating conditions of the batch process of As (V adsorption such as pH, adsorbent dose, contact time, and initial concentration of As (V solution were studied, and optimized. The thermodynamic study of the process showed that arsenate adsorption was endothermic. The kinetic model corresponded to the pseudo-second-order model. The Langmuir adsorption isotherm was better fitted to the experimental data. The Fe2O3/Al2O3 adsorbent was immobilized on leca granules and applied for As (V adsorption. The results showed that the immobilization of Fe2O3/Al2O3 on leca particles improved the As (V removal efficiency.

  2. Monitoring and toxicity evaluation of phytoplankton on lithium manganese oxide adsorbents at lithium recovery pilot plant field.

    Science.gov (United States)

    Yoon, H. O.; Kim, J. A.; Kim, J. C.; Chung, K. S.; Ryu, J. H.

    2015-12-01

    For recovery of rare mineral resources such as lithium or boron from seawater, the lithium adsorbent material have been made by Korea Institute of Geoscience and Mineral Resources (KIGAM) and pilot plant was conducted in Okgye Harbor, Gangneung, Korea. The application of lithium adsorbent in pilot plant, it is important to consider the impact on the marine environment. Especially phytoplankton communities are important marine microorganism to represent marine primary product. At the same time, phytoplankton is possible to induce the decrease of lithium recovery rate due to cause of biofouling to surfaces of lithium adsorbents. Therefore long-term and periodic monitoring of phytoplankton is necessary to understand the environmental impact and biofouling problems near the lithium pilot plant. The abundance and biomass of phytoplankton have been evaluated through monthly interval sampling from February 2013 to May 2015. Abundance and species diversity of phytoplankton went up to summer from winter. When lithium adsorbents were immersing to seawater, eco-toxicities of released substances were determined using Microtox with bioluminescence bacteria Vibrio fischeri. The adsorbents were soaked in sterilized seawater and aeration for 1, 3, 5, 7, 10 and 14 days intervals under controlled temperature. Maximum EC50 concentration was 61.4% and this toxicity was showed in more than 10 days exposure.

  3. 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.

  4. 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.

  5. REMOVAL OF REACTIVE DYES FROM WASTEWATER OF TEXTILE INDUSTRIES BY USING ENVIRONMENTAL FRIENDLY ADSORBENTS

    Directory of Open Access Journals (Sweden)

    ALAM Md Shamim

    2016-05-01

    Full Text Available This paper is aimed at developing a method to treat wastewater by using inexpensive adsorbents. Textile industries produce wastewater, otherwise known as effluent, as a bi-product of their production. The effluent contains several pollutants. Among the various stages of textile production, the operations in the dyeing plant, which include pre-treatments, dyeing, printing and finishing, produce the most pollution. The textile dyeing wastes contain unused or partially used organic compounds, and high level of different pollutants. They are often of strong color and may also be of high temperature. When disposed into water bodies or onto land these effluents will result in the deterioration of ecology and damage to aquatic life. Furthermore they may cause damage to fisheries and economic loss to fishermen and farmer, there may be impacts on human health which can be removed with the help of an effluent treatment plant (ETP. The “clean” water can then be safely discharged into the environment and ultimately save our environment from pollution. In this study, rice husk and cotton dust were used as an adsorbent. In this research work waste water was characterized with this useless adsorbents. The parameters which were tested in this study are DO, BOD, COD, TS, TDS and TSS. The results showed that the selected bio adsorbents have good potential for removal of reactive dyes from textile effluent.

  6. Enhanced adsorption of phenol from water by a novel polar post-crosslinked polymeric adsorbent

    International Nuclear Information System (INIS)

    Zeng Xiaowei; Fan Yunge; Wu Guolin; Wang Chunhong; Shi Rongfu

    2009-01-01

    A novel post-crosslinked polymeric adsorbent PDM-2 was prepared by Friedel-Crafts reaction of pendant vinyl groups without external crosslinking agent. Both the specific surface area and the pore volume of starting copolymer PDM-1 increased significantly after post-crosslinking. Batch adsorption runs of phenol from aqueous solution onto PDM-1 and PDM-2 were investigated. Commercial macroporous resins XAD-4 and AB-8 were chosen as the comparison. Experimental results showed that isotherms of phenol adsorption onto these four polymeric adsorbents could be represented by Freundlich model reasonably. PDM-2 exhibited higher adsorption capacity of phenol than other three adsorbents, which resulted from synergistic effect of larger specific surface area and polar groups on the network. The adsorption process for phenol was proved to be exothermic and spontaneous in nature. Thermodynamic parameters such as Gibb's free energy (ΔG), change in enthalpy (ΔH) and change in entropy (ΔS) were calculated. Kinetics studies indicated that phenol uptake onto PDM-1 and PDM-2 followed the pseudo-second order model and the intraparticle diffusion process was a rate-controlling step. Column adsorption runs demonstrated that nearly 100% regeneration efficiency for PDM-2 by 3 BV industrial alcohol and the adsorbate phenol can be easily recovered by further distilling. Continuous column adsorption-regeneration cycles indicated negligible capacity loss of PDM-2 during operation.

  7. Study on radiation-induced polymerization of vinyl monomers adsorbed on inorganic substances. II. Radiation-induced polymerization of methyl methacrylate adsorbed on several inorganic substances

    International Nuclear Information System (INIS)

    Fukano, K.; Kageyama, E.

    1975-01-01

    The radiation-induced polymerization of methyl methacrylate (MMA) adsorbed on such inorganic substances as silica gel, white carbon, silicic acid anhydride, zeolite, and activated alumina was carried out to compare with the case of styrene. The rate of radiation-induced polymerization adsorbed on inorganic substances was high compared with that of radiation-induced bulk state polymerization, as was the case with styrene. Inorganic substrates which contain aluminum as a component element are more likely to be grafted than those which consist of SiO 2 alone, as with styrene. The molecular weight distribution of unextractable polymer and extractable polymer differs, depending on the type of inorganic substance. Experiments by a preirradiation method were carried out in case of silica gel, white carbon, and silicic acid anhydride. GPC spectra of the polymer obtained were different from those of polymer formed by the simultaneous irradiation method. It appears that all the unextractable polymer is grafted to the inorganic surface with chemical bond

  8. Spin currents and filtering behavior in zigzag graphene nanoribbons with adsorbed molybdenum chains

    International Nuclear Information System (INIS)

    García-Fuente, A; Gallego, L J; Vega, A

    2015-01-01

    By means of density-functional-theoretic calculations, we investigated the structural, electronic and transport properties of hydrogen-passivated zigzag graphene nanoribbons (ZGNRs) on which a one-atom-thick Mo chain was adsorbed (with or without one or two missing atoms), or in which the passivating hydrogen atoms were replaced by Mo atoms. Mo-passivated ZGNRs proved to be nonmagnetic. ZGNRs with an adsorbed defect-free Mo chain were most stable with the Mo atoms forming dimers above edge bay sites, which suppressed the magnetic moments of the C atoms in that half of the ribbon; around the Fermi level of these systems, each spin component had a transmission channel via the Mo sp z band and one had an additional channel created by polarization of the ZGNR π * band, leading to a net spin current. The absence of an Mo dimer from an Mo chain adsorbed at the ZGNR edge made the system a perfect spin filter at low voltage bias by suppressing the Mo sp z band channels. Thus this last kind of hybrid system is a potential spin valve. (paper)

  9. The effects of mineral adsorbents added to broilers diet on breast meat quality

    Directory of Open Access Journals (Sweden)

    Okanović Đorđe G.

    2013-01-01

    Full Text Available The aim of these investigations was to determine the influence of mineral adsorbents “Minazel” and “Minazel Plus” added into broiler diet, on the carcass quality and nutritional, technological and sensory properties of breast meat. The examination was done on Cobb 500 provenience divided into 4 groups: control group C (fed without addition of mineral adsorbent, experimental group E I (0.5% of Minazel, experimental group E II (0.2% of Minazel Plus, experimental group E III (0.3% of Minazel Plus. The results showed that the broilers fed with the addition of mineral adsorbents, had a higher (P < 0.01 mass of chilled carcass “ready to grill“ and breast mass, than the broilers of the control group. Based on the parameters and criteria for defining the quality of chicken breast meat (pHu and L* it can be concluded that meat of all groups had in average "normal" quality. According to the results of sensory analyzed roasted breast meat, meat of experimental groups had preferable smell and tenderness. [Projekat Ministarstva nauke Republike Srbije, br. 46012

  10. The design of a modular pilot plant based on the adsorber loop concept

    International Nuclear Information System (INIS)

    Koske, P.H.; Ohlrogge, K.

    1984-01-01

    The main design criteria for a pilot plant producing about 100 t uranium per year from seawater are discussed. The application of the adsorber loop concept for the contact between seawater and the adsorber granulate enables the employment of considerably higher seawater velocities in the adsorber bed in comparison with a fluidized bed thus reducing the necessary bed area. The seawater flow is accomplished by active pumping and the plant is supposed to be operating far from shores on high seas in tropical or subtropical waters. For this range of operation an ordinary ships hull is preferred for the basic structure to some new more sophisticated but unproven design. Depending on the effective flow rate in the adsorption units one or a few ships with standard dimensions (i.e. large container ships of about 50000 BRT; 290 m length; 40 m width) are able to produce the intended amount of 100 tU per year. Besides some information on the theoretical background the essential engineering considerations are presented. (author)

  11. Utilization of mixed adsorbents to extend frying oil life cycle in poultry processing.

    Science.gov (United States)

    Udomkun, Patchimaporn; Innawong, Bhundit; Siasakul, Chatchalai; Okafor, Christopher

    2018-05-15

    The effects were studied of two different adsorbent combinations (com I; bentonite: activated carbon: celite = 3:4:1 and com II; bentonite: activated clay: celite = 3:4:1 + 1% citric acid) on the physico-chemical changes of oil used continuously for deep-fat frying of chicken drumsticks. The results showed that the % FFA was reduced by 44.3, PV by 50.2, and FOS reading by 40.1% in com I whereas reductions of 41.6, 44.9, and 32.8%, respectively, were found in com II. The oil treated with com II exhibited a lighter color than with com I. The changes of oil color in com I were L ∗ 30.7, a ∗ 1.7, and b ∗ 31.9%; in com II they were 53.2, 19.1, and 39.5% respectively. The higher the L ∗ observed, the better the oil quality obtained because of the bleaching ability of adsorbents. Therefore, the use of such adsorbents is recommended for poultry processing. Copyright © 2017 Elsevier Ltd. All rights reserved.

  12. Effectiveness of solar heating systems for the regeneration of adsorbents in recessed fruit and vegetable storages

    International Nuclear Information System (INIS)

    Khuzhakulov, S.M.; Uzakov, G.N.; Vardiyashvili, A.B

    2013-01-01

    A new method for the regeneration of adsorbents using solar heating systems is proposed. It provides energy saving through the control of the gas composition and humidity in recessed fruit and vegetable storages. The effectiveness of solar heating systems, such as a 'hot box' for the regeneration of adsorbents in fruit and vegetable storages is shown. (author)

  13. Adsorbent cartridge for the exhaust of diazo process machines

    International Nuclear Information System (INIS)

    Michlin, N.; Thies, E.J.

    1982-01-01

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

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

    International Nuclear Information System (INIS)

    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 3 , dibutyl phosphate (DBP), UO 2 2+ , Pu 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 3 waste generated per metric ton of nuclear fuel reprocessed would be reduced significantly. 19 references, 6 figures, 12 tables

  15. Carboxymethyl chitosan-modified magnetic-cored dendrimer as an amphoteric adsorbent

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Hye-Ran [Department of Civil and Environmental Engineering, Hanyang University, 222 Wangsimni-ro, Seongdong-gu, Seoul 133-791 (Korea, Republic of); Jang, Jun-Won [Pohang Institute of Metal Industry Advancement, 56 Jigok-ro, Nam-gu, Pohang-si, Gyeongsangbuk-do 790-834 (Korea, Republic of); Park, Jae-Woo, E-mail: jaewoopark@hanyang.ac.kr [Department of Civil and Environmental Engineering, Hanyang University, 222 Wangsimni-ro, Seongdong-gu, Seoul 133-791 (Korea, Republic of)

    2016-11-05

    Highlights: • Carboxymethyl chitosan was attached to magnetic-cored dendrimer as terminal groups. • High sorptive capacity of carboxymethyl chitosan is added to dendritic structure. • This new adsorbent can be easily separated from water with magnetic force. • It could be reused as an adsorbent more than five-times with simple pH adjustment. - Abstract: Carboxymethyl chitosan-modified magnetic-cored dendrimers (CCMDs) were successfully synthesized in a three step method. The synthesized samples were characterized using X-ray diffraction, transmission electron microscopy, scanning electron microscopy, vibrating sample magnetometer, thermogravimetry analysis, zeta potential analyzer, X-ray photoelectron spectroscopy, surface area analysis, and Fourier transform infrared spectroscopy. The CCMD exhibited selective adsorption for anionic and cationic compounds at specific pH conditions. With the substitution of amino groups of MD with carboxymethyl chitosan moieties, the adsorption sites for cationic compounds were greatly increased. Since the adsorption onto CCMD was mainly electrostatic interaction, the adsorption of MB and MO was significantly affected by the pHs. The optimal adsorption pH values were 3 and 11 for MO and MB. The maximal adsorption of MO and MB on the CCMD at pH values of 3 and 11 were 20.85 mg g{sup −1} and 96.31 mg g{sup −1}, respectively. Reuse of the CCMD as an adsorbent was experimentally tested through adsorption and desorption with simple pH control. More than 99% and 91% of the initial adsorption of MB and MO on the CCMD was maintained with five consecutive recycling.

  16. Gas-Solid Reaction Properties of Fluorine Compounds and Solid Adsorbents for Off-Gas Treatment from Semiconductor Facility

    Directory of Open Access Journals (Sweden)

    Shinji Yasui

    2012-01-01

    Full Text Available We have been developing a new dry-type off-gas treatment system for recycling fluorine from perfluoro compounds present in off-gases from the semiconductor industry. The feature of this system is to adsorb the fluorine compounds in the exhaust gases from the decomposition furnace by using two types of solid adsorbents: the calcium carbonate in the upper layer adsorbs HF and converts it to CaF2, and the sodium bicarbonate in the lower layer adsorbs HF and SiF4 and converts them to Na2SiF6. This paper describes the fluorine compound adsorption properties of both the solid adsorbents—calcium carbonate and the sodium compound—for the optimal design of the fixation furnace. An analysis of the gas-solid reaction rate was performed from the experimental results of the breakthrough curve by using a fixed-bed reaction model, and the reaction rate constants and adsorption capacity were obtained for achieving an optimal process design.

  17. Characterization of fractals with an adsorbed superfluid film

    International Nuclear Information System (INIS)

    Golov, A.I.; Berkutov, I.B.; Babuin, S.; Cousins, D.J.

    2003-01-01

    The tortuosity of a capillary-condensed film of superfluid 4 He adsorbed on 91%-porous silica aerogel has been measured, with transverse sound, as a function of helium coverage. Complementary data from 4 He adsorption isotherms and small-angle X-ray scattering have also been used for substrate characterization. The tortuosity is found to be roughly inversely proportional to the volume fraction of the liquid phase of helium

  18. The influence of white and blue silica gels as adsorbents in adsorptive-distillation of ethanol-water mixture

    Science.gov (United States)

    Megawati, Jannah, Reni Ainun; Rahayuningtiyas, Indi

    2017-01-01

    This research studied the difference of white and blue silica gels when used as an adsorbent for ethanol purification that is processed via Adsorptive-Distillation (AD) at 1 atm pressure. The effect of process duration to purification process is also recorded and studied to evaluate the performance of designed AD equipment. The experiment was conducted using boiling flask covered with a heating mantle and the temperature was maintained at 78°C. The vapour flowed into the adsorbent column and was condensed using water as a cooling medium. The initial ethanol concentration was 90.8% v/v and volume was 300 mL. Experiment shows that designed AD equipment could be used to purify ethanol. The average vapour velocity was about 39.29 and 45.91 m/s for white and blue silica gels, respectively, which is considered very high. Therefore the saturated adsorption could not be obtained. Highest ethanol concentration achieved using white silica gel is about 96.671% v/v after 50 minutes. Thus AD with white silica gel showed good performance and passed azeotropic point. But AD with blue silica gel showed a different result, the adsorption of blue silica gel failed to break the azeotropic point. The outlet average water concentration for white and blue silica gels is 3.54 and 3.42 mole/L. Based on the weight ratio of adsorbed water per adsorbent, at 55th minutes of time; this ratio of blue silica gel is about 0.053 gwater/gads. The time required by the blue silica to achieve 0.5 wwater-adsorbed/wwater-initial is 45 minutes, and the average outlet water concentration is 3.42 mole/L. Meanwhile, the time required by a white silica to complete 0.5 wwater-adsorbed/wwater-initial is 35 minutes, and the average outlet water level is 3.54 mole/L. Based on the results, the blue silica as an adsorbent for AD of ethanol-water mixture is better than white silica gel.

  19. [Characteristics and comparative study of a new drinking-water defluoridation adsorbent Bio-F].

    Science.gov (United States)

    Zhu, Chi; Zhao, Liang-Yuan; Yuan, Heng; Yang, Han-Ying; Li, Ang; Wang, Peng; Yang, Shao

    2009-04-15

    To evaluate the application potentiality pf a new type drinking-water defluoridation adsorbent Bio-F, comparative study on the defluoridation characteristics of common adsorbents activated alumina (AA), bone char (BC), activated clinoptilolite (AC) with Bio-F was conducted. The defluoridation characteristics under different conditions, such as particle diameter, pH, retention time, fluorine concentration, regeneration stability, were investigated by continuous-flow column experiments and static tests. The defluoridation efficiency of high fluoride underground water by four types of adsorbents was also compared. The results showed that F(-) adsorption kinetics of Bio-F fitted the Lagergren First-order equation (R2 = 0.9580). F(-) adsorption by Bio-F was found to fit the Langmuir adsorption isotherm (R2 = 0.9992). The results indicated that the static defluoridation capacity (DC) of Bio-F was 4.0883 mg x g(-1), which was about 1.8 folds and 5.8 folds of those of AA and AC respectively. DC of all four adsorbents was positively correlated with F(-) concentration and negatively correlated with particle size. High concentration of CO3(2-) and HCO3(-) reduced the DC of Bio-F (p retention time of Bio-F was 3-4 min, which was less than that of AC (20 min) and AA (11 min). The DC of Bio-F remained relatively stable in pH 4.0-9.0 and in regeneration since the DC variation was not more than 15%. The above results indicated that Bio-F was superior to AA, BC and AC in drinking-water defluoridation.

  20. Volumetric interpretation of protein adsorption: interfacial packing of protein adsorbed to hydrophobic surfaces from surface-saturating solution concentrations.

    Science.gov (United States)

    Kao, Ping; Parhi, Purnendu; Krishnan, Anandi; Noh, Hyeran; Haider, Waseem; Tadigadapa, Srinivas; Allara, David L; Vogler, Erwin A

    2011-02-01

    The maximum capacity of a hydrophobic adsorbent is interpreted in terms of square or hexagonal (cubic and face-centered-cubic, FCC) interfacial packing models of adsorbed blood proteins in a way that accommodates experimental measurements by the solution-depletion method and quartz-crystal-microbalance (QCM) for the human proteins serum albumin (HSA, 66 kDa), immunoglobulin G (IgG, 160 kDa), fibrinogen (Fib, 341 kDa), and immunoglobulin M (IgM, 1000 kDa). A simple analysis shows that adsorbent capacity is capped by a fixed mass/volume (e.g. mg/mL) surface-region (interphase) concentration and not molar concentration. Nearly analytical agreement between the packing models and experiment suggests that, at surface saturation, above-mentioned proteins assemble within the interphase in a manner that approximates a well-ordered array. HSA saturates a hydrophobic adsorbent with the equivalent of a single square or hexagonally-packed layer of hydrated molecules whereas the larger proteins occupy two-or-more layers, depending on the specific protein under consideration and analytical method used to measure adsorbate mass (solution depletion or QCM). Square or hexagonal (cubic and FCC) packing models cannot be clearly distinguished by comparison to experimental data. QCM measurement of adsorbent capacity is shown to be significantly different than that measured by solution depletion for similar hydrophobic adsorbents. The underlying reason is traced to the fact that QCM measures contribution of both core protein, water of hydration, and interphase water whereas solution depletion measures only the contribution of core protein. It is further shown that thickness of the interphase directly measured by QCM systematically exceeds that inferred from solution-depletion measurements, presumably because the static model used to interpret solution depletion does not accurately capture the complexities of the viscoelastic interfacial environment probed by QCM. Copyright © 2010

  1. Electronically driven adsorbate excitation mechanism in femtosecond-pulse laser desorption

    DEFF Research Database (Denmark)

    Brandbyge, Mads; Hedegård, Per; Heinz, T. F.

    1995-01-01

    a systematic theoretical treatment of this coupling process in the language of an electronic friction, which generates Langevin noise in the adsorbate center-of-mass degrees of freedom, while the electronic degrees of freedom are at a high temperature. Starting from an influence-functional path...

  2. Study of the Relationship between Taste Sensor Response and the Amount of Epigallocatechin Gallate Adsorbed Onto a Lipid-Polymer Membrane

    Directory of Open Access Journals (Sweden)

    Yuhei Harada

    2015-03-01

    Full Text Available A taste sensor using lipid-polymer membranes has been developed to evaluate the taste of foods, beverages and medicines. The response of the taste sensor, measured as a change in the membrane potential caused by adsorption (CPA, corresponds to the aftertaste felt by humans. The relationships between the CPA value and the amount of adsorbed taste substances, quinine and iso-α acid (bitterness, and tannic acid (astringency, have been studied so far. However, that of epigallocatechin gallate (EGCg has not been clarified, although EGCg is abundantly present in green tea as one of its astringent substances. This study aimed at clarifying the response of the taste sensor to EGCg and its relationship with the amount of EGCg adsorbed onto lipid-polymer membranes. The lipid concentration dependence of the CPA value was similar to that of the amount of adsorbed EGCg, indicating a high correlation between the CPA value and the amount of adsorbed EGCg. The CPA value increased with increasing amount of adsorbed EGCg; however, the CPA value showed a tendency of leveling off when the amount of adsorbed EGCg further increased.

  3. Diffusion-controlled oxygen reduction on multi-copper oxidase-adsorbed carbon aerogel electrodes without mediator

    Energy Technology Data Exchange (ETDEWEB)

    Tsujimura, S.; Kamitaka, Y.; Kano, K. [Division of Applied Life Sciences, Graduate School of Agriculture, Kyoto University, Sakyo-ku, Kyoto (Japan)

    2007-12-15

    Bioelectrocatalytic reduction of O{sub 2} into water was archived at diffusion-controlled rate by using enzymes (laccase from Trametes sp. and bilirubin oxidase from Myrothecium verrucaria, which belong to the family of multi-copper oxidase) adsorbed on mesoporous carbon aerogel particle without a mediator. The current density was predominantly controlled by the diffusion of dissolved O{sub 2} in rotating-disk electrode experiments, and reached a value as large as 10 mA cm{sup -2} at 1 atm O{sub 2}, 25 C, and 8,000 rpm on the laccase-adsorbed electrode. The overpotential of the bioelectrocatalytic reduction of O{sub 2} was 0.4-0.55 V smaller than that observed on a Pt disk electrode. Without any optimization, the laccase-adsorbed biocathode showed stable current intensity of the O{sub 2} reduction in an air-saturated buffer at least for 10 days under continuous flow system. (Abstract Copyright [2007], Wiley Periodicals, Inc.)

  4. Elementary sulfur in effluent from denitrifying sulfide removal process as adsorbent for zinc(II).

    Science.gov (United States)

    Chen, Chuan; Zhou, Xu; Wang, Aijie; Wu, Dong-hai; Liu, Li-hong; Ren, Nanqi; Lee, Duu-Jong

    2012-10-01

    The denitrifying sulfide removal (DSR) process can simultaneously convert sulfide, nitrate and organic compounds into elementary sulfur (S(0)), di-nitrogen gas and carbon dioxide, respectively. However, the S(0) formed in the DSR process are micro-sized colloids with negatively charged surface, making isolation of S(0) colloids from other biological cells and metabolites difficult. This study proposed the use of S(0) in DSR effluent as a novel adsorbent for zinc removal from wastewaters. Batch and continuous tests were conducted for efficient zinc removal with S(0)-containing DSR effluent. At pHremoval rates of zinc(II) were increased with increasing pH. The formed S(0) colloids carried negative charge onto which zinc(II) ions could be adsorbed via electrostatic interactions. The zinc(II) adsorbed S(0) colloids further enhanced coagulation-sedimentation efficiency of suspended solids in DSR effluents. The DSR effluent presents a promising coagulant for zinc(II) containing wastewaters. Copyright © 2012 Elsevier Ltd. All rights reserved.

  5. Kinetic studies of adsorption in the bioethanol dehydration using polyvinyl alcohol, zeolite and activated carbon as adsorbent

    Science.gov (United States)

    Laksmono, J. A.; Pratiwi, I. M.; Sudibandriyo, M.; Haryono, A.; Saputra, A. H.

    2017-11-01

    Bioethanol is considered as the most promising alternative fuel in the future due to its abundant renewable sources. However, the result of bioethanol production process using fermentation contains 70% v/v, and it still needs simultaneous purification process. One of the most energy-efficient purification methods is adsorption. Specifically, the rate of adsorption is an important factor for evaluating adsorption performance. In this work, we have conducted an adsorption using polyvinyl alcohol (PVA), zeolite and activated carbon as promising adsorbents in the bioethanol dehydration. This research aims to prove that PVA, zeolite, activated carbon is suitable to be used as adsorbent in bioethanol dehydration process through kinetics study and water adsorption selectivity performance. According to the results, PVA, zeolite and activated carbon are the potential materials as adsorbents in the bioethanol dehydration process. The kinetics study shows that 30°C temperature gave the optimum adsorption kinetics rate for PVA, zeolite, and activated carbon adsorbents which were 0.4911 min-1; 0.5 min-1; and 1.1272 min-1 respectively. In addition, it also shows that the activated carbon performed as a more potential adsorbent due to its higher pore volume and specific surface area properties. Based on the Arrhenius equation, the PVA works in the chemisorption mechanism, meanwhile zeolite and activated carbon work in the physisorption system as shown in the value of the activation energy which are 51.43 kJ/mole; 8.16 kJ/mole; and 20.30 kJ/mole. Whereas the water to ethanol selectivity study, we discover that zeolite is an impressive adsorbent compared to the others due to the molecular sieving characteristic of the material.

  6. Recovery of iron oxides from acid mine drainage and their application as adsorbent or catalyst.

    Science.gov (United States)

    Flores, Rubia Gomes; Andersen, Silvia Layara Floriani; Maia, Leonardo Kenji Komay; José, Humberto Jorge; Moreira, Regina de Fatima Peralta Muniz

    2012-11-30

    Iron oxide particles recovered from acid mine drainage represent a potential low-cost feedstock to replace reagent-grade chemicals in the production of goethite, ferrihydrite or magnetite with relatively high purity. Also, the properties of iron oxides recovered from acid mine drainage mean that they can be exploited as catalysts and/or adsorbents to remove azo dyes from aqueous solutions. The main aim of this study was to recover iron oxides with relatively high purity from acid mine drainage to act as a catalyst in the oxidation of dye through a Fenton-like mechanism or as an adsorbent to remove dyes from an aqueous solution. Iron oxides (goethite) were recovered from acid mine drainage through a sequential precipitation method. Thermal treatment at temperatures higher than 300 °C produces hematite through a decrease in the BET area and an increase in the point of zero charge. In the absence of hydrogen peroxide, the solids adsorbed the textile dye Procion Red H-E7B according to the Langmuir model, and the maximum amount adsorbed decreased as the temperature of the thermal treatment increased. The decomposition kinetics of hydrogen peroxide is dependent on the H(2)O(2) concentration and iron oxides dosage, but the second-order rate constant normalized to the BET surface area is similar to that for different iron oxides tested in this and others studies. These results indicate that acid mine drainage could be used as a source material for the production of iron oxide catalysts/adsorbents, with comparable quality to those produced using analytical-grade reagents. Copyright © 2012 Elsevier Ltd. All rights reserved.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2013-07-01

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

  8. Simplified radioimmunoassay of urinary drugs of abuse adsorbed on ion-exchange papers

    Energy Technology Data Exchange (ETDEWEB)

    Alexander, G.J.; Machiz, S.

    1977-10-01

    A convenient screening procedure for presence of drugs of abuse in urine consists of two steps: adsorption of the drugs from urine onto a paper loaded with cation-exchange resin and detection of the adsorbed drugs by direct radioimmunoassay. The first step can be performed in the field, the second in a central laboratory. Storage and transport to the laboratory are simplified because specimens adsorbed on dried paper are stable and can be sent in letter-mail. In the laboratory, a small disc of the ion-exchange paper is exposed to antigen and antibody, rinsed, and tested for radioactivity. Discs treated with positive urines are more radioactive than discs from negative urines.

  9. Aggregate formation of eosin-Y adsorbed on nanocrystalline TiO2 films

    Science.gov (United States)

    Yaguchi, Kaori; Furube, Akihiro; Katoh, Ryuzi

    2012-11-01

    We have studied the adsorption of eosin-Y on nanocrystalline TiO2 films with two different solvents namely acetonitrile (ACN) and ethanol (EtOH). A Langmuir-type adsorption isotherm was observed with ACN. In contrast, a Freundlich-type adsorption isotherm was observed with EtOH, suggesting that EtOH molecules co-adsorbed on TiO2 surface. Absorption spectra of the dye adsorbed films clearly show aggregate formation at high concentrations of dye in the solutions. From the analysis of the spectra, we conclude that head-to-tail type aggregates are observed with ACN, whereas various types of aggregates, including H-type and head-to-tail type aggregates, are observed with EtOH.

  10. Carbonised jackfruit peel as an adsorbent for the removal of Cd(II) from aqueous solution.

    Science.gov (United States)

    Inbaraj, B Stephen; Sulochana, N

    2004-08-01

    The fruit of the jack (Artocarpus heterophyllus) is one of the popular fruits in India, where the total area under this fruit is about 13,460 ha. A significant amount of peel (approximately 2,714-11,800 kg per tree per year) is discarded as agricultural waste, as apart from its use as a table fruit, it is popular in many culinary preparations. Treatment of jackfruit peel with sulphuric acid produced a carbonaceous product which was used to study its efficiency as an adsorbent for the removal of Cd(II) from aqueous solution. Batch experiments were performed as a function of process parameters; agitation time, initial metal concentration, adsorbent concentration and pH. Kinetic analyses made with Lagergren pseudo-first-order, Ritchie second-order and modified Ritchie second-order models showed better fits with modified Ritchie second-order model. The Langmuir-Freundlich (Sips equation) model best defined the experimental equilibrium data among the three isotherm models (Freundlich, Langmuir and Langmuir-Freundlich) tested. Taking a particular metal concentration, the optimum dose and pH required for the maximum metal removal was established. A complete recovery of the adsorbed metal ions from the spent adsorbent was achieved by using 0.01 M HCl.

  11. In vitro hydroxyapatite adsorbed salivary proteins

    International Nuclear Information System (INIS)

    Vitorino, Rui; Lobo, Maria Joao C.; Duarte, Jose; Ferrer-Correia, Antonio J.; Tomer, Kenneth B.; Dubin, Joshua R.; Domingues, Pedro M.; Amado, Francisco M.L.

    2004-01-01

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

  12. Solid-phase extraction and determination of trace elements in environmental samples using naphthalene adsorbent

    International Nuclear Information System (INIS)

    Pourreza, N.

    2004-01-01

    Naphthalene co-precipitated with quaternary ammonium salt such as tetraoctyl ammonium bromide and methyltrioctyl ammonium chloride have been used as adsorbent for solid phase extraction of metal ions such as Hg, Cd and Fe. The metal ions are retained on the adsorbent in a column as their complexes with suitable ligands and eluted by an eluent before instrumental measurements. The optimization of the procedures for solid phase extraction and consequent determination of trace elements and application to environmental samples especially water samples will be discussed. (author)

  13. Mass and Force Sensing of an Adsorbate on a Beam Resonator Sensor

    Directory of Open Access Journals (Sweden)

    Yin Zhang

    2015-06-01

    Full Text Available The mass sensing superiority of a micro-/nano-mechanical resonator sensor over conventional mass spectrometry has been, or at least is being firmly established. Because the sensing mechanism of a mechanical resonator sensor is the shifts of resonant frequencies, how to link the shifts of resonant frequencies with the material properties of an analyte formulates an inverse problem. Besides the analyte/adsorbate mass, many other factors, such as position and axial force, can also cause the shifts of resonant frequencies. The in situ measurement of the adsorbate position and axial force is extremely difficult if not impossible, especially when an adsorbate is as small as a molecule or an atom. Extra instruments are also required. In this study, an inverse problem of using three resonant frequencies to determine the mass, position and axial force is formulated and solved. The accuracy of the inverse problem solving method is demonstrated, and how the method can be used in the real application of a nanomechanical resonator is also discussed. Solving the inverse problem is helpful to the development and application of a mechanical resonator sensor for two reasons: reducing extra experimental equipment and achieving better mass sensing by considering more factors.

  14. Removal of basic dye from aqueous solutions using nano scale zero valent iron (NZVI) as adsorbent

    International Nuclear Information System (INIS)

    Khan, M. S.; Ahmad, A.; Bangash, F. K.; Shah, S. S.; Khan, P.

    2013-01-01

    Nano scale zero valent iron (NZVI) was synthesized and tested for the purification of waste water contaminated by the organic pollutants. In the present study removal of basic blue 3 dye was investigated by NZVI adsorbent. NZVI adsorbent was prepared in the presence of N/sub 2/ gas atmosphere by sodium boro- hydrate (NaHB/sub 4/) reduction method. The particle size of the prepared adsorbent was approximately in the range of 1 x 10/sup -2/nm to 2 x 10/sup -2/nm. The adsorption of basic blue 3 dyes was confirmed with various parameters such as ionic strength, contact time and initial dye concentrations. The experiments were carried out in a batch mode technique. The surface morphology was studied by SEM analysis technique. (author)

  15. Surface-enhanced raman spectroscopy of quinomethionate adsorbed on silver colloids

    International Nuclear Information System (INIS)

    Kim, Mak Soon; Kang, Jae Soo; Park, Si Bum; Lee, Mu Sang

    2003-01-01

    We have studied the surface-enhanced Raman spectroscopy (SERS) spectrum of quinomethionate (6-methyl-1,3-dithiolo(4,5-b)quinoxalin-2-one), which is an insecticide or fungicide used on vegetables and wheat. We observed no signals in the ordinary Raman spectra of solid-state quinomethionate, but when it was adsorbed on a colloidal silver surface, strong vibrational signals were obtained at a very low concentration. The SERS spectra were obtained by silver colloids prepared by the Creighton et al. method. The influence of pH and the aggregation inductors (Cl - , Br - , I - , F - ) on the adsorption mechanism was investigated. Two different adsorption mechanisms were deduced, depending on the experimental conditions: The one N atom or two N atoms are chemisorbed on an Ag surface. An important contribution of the chemical mechanism was inferred when the one N atom was perpendicularly adsorbed on a surface. It is possible that quinomethionate can be detected to about 10 -5 M

  16. INTERACTION OF CARBON DIOXIDE WITH CARBON ADSORBENTS BELOW 400 C

    Energy Technology Data Exchange (ETDEWEB)

    Deitz, V R; Carpenter, F G; Arnold, R G

    1963-06-15

    The adsorption of carbon dioxide on carbon adsorbents (FT carbon, coconut charcoal, acid-washed bone char) and adsorbents containing basic calcium phosphate (hydroxylapatite, bone char, ash of bone char) was studied. Special consideration was given to the pretreatment of the materials. The carbons equilibrated as rapidly as the temperature; the basic calcium phosphates showed a rapid initial adsorption followed by a very slow rate which continued for days. Linear adsorption isotherms were found on FT carbon and the isosteric heats varied slightiy with coverage. The isotherms for the remaining materials had varying curvature and were for the most part in the same sequence as the estimated surface areas. The isosteric heats of carbon dioxide correlated very well with the magnitude of surface hydroxyl groups, an estimate of which was made from the chemical composition. There appeared to be three increasing levels of interaction: (1) pure physical adsorption; (2) an adsorption complex having 'bicarbonate structure'; and (3) an adsorption complex having 'carbonate structure'. (auth)

  17. Pulling adsorbed polymers at an angle: A low temperature theory

    Science.gov (United States)

    Iliev, Gerasim; Whittington, Stuart

    2012-02-01

    We consider several partially-directed walk models in two- and three-dimensions to study the problem of a homopolymer interacting with a surface while subject to a force at the terminal monomer. The force is applied with a component parallel to the surface as well as a component perpendicular to the surface. Depending on the relative values of the force in each direction, the force can either enhance the adsorption transition or lead to desorption in an adsorbed polymer. For each model, we determine the associated generating function and extract the phase diagram, identifying states where the polymer is thermally desorbed, adsorbed, and under the influence of the force. We note the different regimes that appear in the problem and provide a low temperature approximation to describe them. The approximation is exact at T=0 and models the exact results extremely well for small values of T. This work is an extension of a model considered by S. Whittington and E. Orlandini.

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

    International Nuclear Information System (INIS)

    Tsezos, M.

    1983-01-01

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

  19. Low concentration CO2 capture using physical adsorbents: Are Metal-Organic Frameworks becoming the new benchmark materials?

    KAUST Repository

    Belmabkhout, Youssef; Guillerm, Vincent; Eddaoudi, Mohamed

    2016-01-01

    The capture and separation of traces and concentrated CO2 from important commodities such as CH4, H2, O2 and N2, is becoming important in many areas related to energy security and environmental sustainability. While trace CO2 concentration removal applications have been modestly studied for decades, the spike in interest in the capture of concentrated CO2 was motivated by the need for new energy vectors to replace highly concentrated carbon fuels and the necessity to reduce emissions from fossil fuel-fired power plants. CO2 capture from various gas streams, at different concentrations, using physical adsorbents, such as activated carbon, zeolites, and metal-organic frameworks (MOFs), is attractive. However, the adsorbents must be designed with consideration of many parameters including CO2 affinity, kinetics, energetics, stability, capture mechanism, in addition to cost. Here, we perform a systematic analysis regarding the key technical parameters that are required for the best CO2 capture performance using physical adsorbents. We also experimentally demonstrate a suitable material model of Metal Organic Framework as advanced adsorbents with unprecedented properties for CO2 capture in a wide range of CO2 concentration. These recently developed class of MOF adsorbents represent a breakthrough finding in the removal of traces CO2 using physical adsorption. This platform shows colossal tuning potential for more efficient separation agents.

  20. Low concentration CO2 capture using physical adsorbents: Are Metal-Organic Frameworks becoming the new benchmark materials?

    KAUST Repository

    Belmabkhout, Youssef

    2016-03-30

    The capture and separation of traces and concentrated CO2 from important commodities such as CH4, H2, O2 and N2, is becoming important in many areas related to energy security and environmental sustainability. While trace CO2 concentration removal applications have been modestly studied for decades, the spike in interest in the capture of concentrated CO2 was motivated by the need for new energy vectors to replace highly concentrated carbon fuels and the necessity to reduce emissions from fossil fuel-fired power plants. CO2 capture from various gas streams, at different concentrations, using physical adsorbents, such as activated carbon, zeolites, and metal-organic frameworks (MOFs), is attractive. However, the adsorbents must be designed with consideration of many parameters including CO2 affinity, kinetics, energetics, stability, capture mechanism, in addition to cost. Here, we perform a systematic analysis regarding the key technical parameters that are required for the best CO2 capture performance using physical adsorbents. We also experimentally demonstrate a suitable material model of Metal Organic Framework as advanced adsorbents with unprecedented properties for CO2 capture in a wide range of CO2 concentration. These recently developed class of MOF adsorbents represent a breakthrough finding in the removal of traces CO2 using physical adsorption. This platform shows colossal tuning potential for more efficient separation agents.

  1. A remarkable adsorbent for removal of contaminants of emerging concern from water: Porous carbon derived from metal azolate framework-6.

    Science.gov (United States)

    Bhadra, Biswa Nath; Jhung, Sung Hwa

    2017-10-15

    A series of metal-azolate frameworks or MAFs-MAF-4, -5, and -6-were synthesized and pyrolyzed to prepare porous carbons derived from MAFs (CDM-4, -5, -6, respectively). Not only the obtained carbons but also MAFs were characterized and applied for the adsorption of organic contaminants of emerging concern (CECs, including pharmaceuticals and personal care products) such as salicylic acid, clofibric acid, diclofenac sodium, bisphenol-A, and oxybenzone (OXB) from water. CDM-6 was found to be the most remarkable adsorbent among the tested ones (including activated carbon) for all the adsorbates. OXB was taken as a representative adsorbate for detailed adsorption studies as well as understanding the adsorption mechanism. H-bonding (H-acceptor: CDM; H-donor: CECs) was suggested as the principal mechanism for the adsorption of tested adsorbates. Finally, CDMs, especially CDM-6, were suggested as highly efficient and easily recyclable adsorbents for water purification. Copyright © 2017 Elsevier B.V. All rights reserved.

  2. A potential low cost adsorbent for the removal of cationic dyes from aqueous solutions

    Science.gov (United States)

    Uddin, Md. Tamez; Rahman, Md. Arifur; Rukanuzzaman, Md.; Islam, Md. Akhtarul

    2017-10-01

    This study was aimed at using mango leaf powder (MLP) as a potential adsorbent for the removal of methylene blue (MB) from aqueous solutions. Characterization of the adsorbent was carried out with scanning electron microscopy, Fourier transform infrared spectroscopy, and nitrogen adsorption-desorption analysis. The pH at the point of zero charge of the adsorbent was determined by titration method and was found a value to be 5.6 ± 0.2. Batch studies were performed to evaluate the influence of various experimental parameters like initial solution pH, contact time, initial concentration of dye and adsorbent dosage on the removal of MB. An adsorption-desorption study was carried out resulting the mechanism of adsorption was carried out by electrostatic force of attraction. The adsorption equilibrium time required for the adsorption of MB on MLP was almost 2 h and 85 ± 5% of the total amount of dye uptake was found to occur in the first rapid phase (30 min). The Langmuir and Freundlich isotherm models were used for modeling the adsorption equilibrium. The experimental equilibrium data could be well interpreted by Langmuir isotherm with maximum adsorption capacity of 156 mg/g. To state the sorption kinetics, the fits of pseudo-first-order and pseudo-second-order kinetic models were investigated. It was obtained that the adsorption process followed the pseudo-second-order rate kinetics. The above findings suggest that MLP can be effectively used for decontamination of dye containing wastewater.

  3. Remediation of Organic and Inorganic Arsenic Contaminated Groundwater using a Nonocrystalline TiO2 Based Adsorbent

    Energy Technology Data Exchange (ETDEWEB)

    Jing, C.; Meng, X; Calvache, E; Jiang, G

    2009-01-01

    A nanocrystalline TiO2-based adsorbent was evaluated for the simultaneous removal of As(V), As(III), monomethylarsonic acid (MMA), and dimethylarsinic acid (DMA) in contaminated groundwater. Batch experimental results show that As adsorption followed pseudo-second order rate kinetics. The competitive adsorption was described with the charge distribution multi-site surface complexation model (CD-MUSIC). The groundwater containing an average of 329 ?g L-1 As(III), 246 ?g L-1 As(V), 151 ?g L-1 MMA, and 202 ?g L-1 DMA was continuously passed through a TiO2 filter at an empty bed contact time of 6 min for 4 months. Approximately 11 000, 14 000, and 9900 bed volumes of water had been treated before the As(III), As(V), and MMA concentration in the effluent increased to 10 ?g L-1. However, very little DMA was removed. The EXAFS results demonstrate the existence of a bidentate binuclear As(V) surface complex on spent adsorbent, indicating the oxidation of adsorbed As(III). A nanocrystalline TiO2-based adsorbent could be used for the simultaneous removal of As(V), As(III), MMA, and DMA in contaminated groundwater.

  4. Adsorptive removal of organics from aqueous phase by acid-activated coal fly ash: preparation, adsorption, and Fenton regenerative valorization of "spent" adsorbent.

    Science.gov (United States)

    Wang, Nannan; Hao, Linlin; Chen, Jiaqing; Zhao, Qiang; Xu, Han

    2018-05-01

    Raw coal fly ash was activated to an adsorbent by sulfuric acid impregnation. The activation condition, the adsorption capacity, and the regenerative valorization of the adsorbent were studied. The results show that the optimal preparation conditions of the adsorbent are [H 2 SO 4 ] = 1 mol L -1 , activation time = 30 min, the ratio of coal fly ash to acid = 1:20 (g:mL), calcination temperature = 100 °C. The adsorption of p-nitrophenol on the adsorbent accords with the pseudo-second-order kinetic equation and the adsorption rate constant is 0.089 g mg -1  min -1 . The adsorption on this adsorbent can be considered enough after 35 min, when the corresponding adsorption capacity is 1.07 mg g -1 (85.6% of p-nitrophenol removal). Compared with raw coal fly ash, the adsorbent has a stable adsorption performance at low pH range (pH = 1-6) and the adsorption of p-nitrophenol is an exothermic process. Ninety minutes is required for the regenerative valorization of saturated adsorbent by Fenton process. The regenerative valorization for this saturated adsorbent can reach 89% under the optimal proposed conditions (30 °C, pH = 3, [H 2 O 2 ] = 5.0 mmol L -1 , [Fe 2+ ] = 5.5 mmol L -1 ). Within 15 experimental runs, the adsorbent has a better and better stability with the increase of experimental runs. Finally, the mechanism of activating coal fly ash is proposed, being verified by the results of the SEM and BET test.

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

    Science.gov (United States)

    Yu, Hongwen; Fugetsu, Bunshi

    2010-05-15

    A novel approach is described for establishing adsorbents for elimination of water-soluble organic dyes by using multi-walled carbon nanotubes (MWCNTs) as the adsorptive sites. Agglomerates of MWCNTs were dispersed into individual tubes (dispersed-MWCNTs) using sodium n-dodecyl itaconate mixed with 3-(N,N-dimethylmyristylammonio)-propanesulfonate as the dispersants. The resultant dispersed-MWCNTs were inserted into cavities of diatomite to form composites of diatomite/MWCNTs. These composites were finally immobilized onto the cell walls of flexible polyurethane foams (PUF) through an in situ PUF formation process to produce the foam-like CNT-based adsorbent. Ethidium bromide, acridine orange, methylene blue, eosin B, and eosin Y were chosen to represent typical water-soluble organic dyes for studying the adsorptive capabilities of the foam-like CNT-based adsorbent. For comparisons, adsorptive experiments were also carried out by using agglomerates of the sole MWCNTs as adsorbents. The foam-like CNT-based adsorbents were found to have higher adsorptive capacities than the CNT agglomerates for all five dyes; in addition, they are macro-sized, durable, flexible, hydrophilic and easy to use. Adsorption isotherms plotted based on the Langmuir equation gave linear results, suggesting that the foam-like CNT-based adsorbent functioned in the Langmuir adsorption manner. The foam-like CNT-based adsorbents are reusable after regeneration with aqueous ethanol solution. Copyright (c) 2009 Elsevier B.V. All rights reserved.

  6. Substrate induced ordering of molecular adsorbates on Au(111)

    International Nuclear Information System (INIS)

    Schott, J.H.; White, H.S.; Arana, C.R.

    1992-01-01

    Using scanning tunneling microscopy in dimethylformate, [Ru(bpy) 2 (bpy-(CH 2 ) x -bpy) 2+ ] (x = 4 and 5) monolayers adsorbed on the unreconstructed and √3 x 22 reconstructed surfaces of Au(111) were imaged in this paper. The substrate had a highly ordered pattern on the reconstructed surface, but random spatial distribution on the unreconstructed surface. 17 refs., 3 figs

  7. Graphene nanosheets and graphite oxide as promising adsorbents for removal of organic contaminants from aqueous solution.

    Science.gov (United States)

    Ji, Liangliang; Chen, Wei; Xu, Zhaoyi; Zheng, Shourong; Zhu, Dongqiang

    2013-01-01

    Graphenes are an emerging class of carbon nanomaterials whose adsorption properties toward organic compounds have not been well understood. In the present study, graphene nanosheets were prepared by reoxidation and abrupt heating of graphite oxide, which was prepared by sequential chemical oxidation of commercial nonporous graphite powder. Adsorption properties of three aromatic compounds (naphthalene, 2-naphthol, and 1-naphthylamine) and one pharmaceutical compound (tylosin) on graphene nanosheets and graphite oxide were examined to explore the potential of these two adsorbents for the removal of organic contaminants from aqueous solutions. Compared with the literature data of adsorption on carbon nanotubes, adsorption of bulky, flexible tylosin on graphene nanosheets exhibited markedly faster adsorption kinetics, which can be attributed to their opened-up layer structure. Graphene nanosheets and graphite oxide showed similar sequences of adsorption affinity: 1-naphthylamine > 2-naphthol > tylosin > naphthalene (with much larger differences observed on graphite oxide). It was proposed that the strong adsorption of the three aromatic compounds was mainly due to π-π electron donor-acceptor interactions with the graphitic surfaces of adsorbents. Additionally, Lewis acid-base interaction was likely an important factor contributing to the strong adsorption of 1-naphthylamine and tylosin, especially for the O-functionality-abundant graphite oxide. After being normalized on the basis of adsorbent surface area, adsorption affinities of all four tested adsorbates on graphene nanosheets were very close to those on nonporous graphite powder, reflecting complete accessibility of the adsorbent surface area in adsorption. Copyright © by the American Society of Agronomy, Crop Science Society of America, and Soil Science Society of America, Inc.

  8. Removal of Ni(II from aqueous solution using leaf, bark and seed of Moringa stenopetala adsorbents

    Directory of Open Access Journals (Sweden)

    A. A. Mengistie

    2013-04-01

    Full Text Available The present study investigates the possibility of using leaf, bark and seed of Moringa stenopetala as alternative adsorbents for removal of Ni(II from aqueous solutions. The optimum adsorption conditions for removal of Ni(II were found to be 30, 20 and 50 mg/L initial concentration, 1.5, 2 and 2.5 g adsorbent dose, 250, 250 and 300 rpm agitation speed, 90, 120 and 90 min contact time, 40, 30 and 23 oC temperature and pH of 5, 6 and 6 using leaf, bark and seed as adsorbent, respectively. At optimum experimental conditions the percent adsorption of synthetic wastewater sample was found to be 93.90, 96.25 and 97.50 for leaf, bark and seed, respectively. The tested experimental data best fits to pseudo-second order (R2 > 0.98 than pseudo-first order, Elovich and intraparticle diffusion kinetic models indicating rate limiting step to be chemisorption. It also fits to Langmuir (R2 > 0.895 using adsorbate variation and also R2 > 0.998 using both time and temperature variation data than Freundlich, Temkin and D-R isotherm models. D-R isotherm and thermodynamic study reveals formation of physical adsorption. Hence the adsorption mechanism could be regarded as physico-chemical adsorption process. The adsorption results of industrial wastewater also reveal that for removal of nickel 83% and 85% was obtained using bark and seed adsorbents, respectively. The new method of adsorption developed in this study is cheap, fast and environmental friendly.DOI: http://dx.doi.org/10.4314/bcse.v27i1.4

  9. Adsorption of aromatic compounds by carbonaceous adsorbents: a comparative study on granular activated carbon, activated carbon fiber, and carbon nanotubes.

    Science.gov (United States)

    Zhang, Shujuan; Shao, Ting; Kose, H Selcen; Karanfil, Tanju

    2010-08-15

    Adsorption of three aromatic organic compounds (AOCs) by four types of carbonaceous adsorbents [a granular activated carbon (HD4000), an activated carbon fiber (ACF10), two single-walled carbon nanotubes (SWNT, SWNT-HT), and a multiwalled carbon nanotube (MWNT)] with different structural characteristics but similar surface polarities was examined in aqueous solutions. Isotherm results demonstrated the importance of molecular sieving and micropore effects in the adsorption of AOCs by carbonaceous porous adsorbents. In the absence of the molecular sieving effect, a linear relationship was found between the adsorption capacities of AOCs and the surface areas of adsorbents, independent of the type of adsorbent. On the other hand, the pore volume occupancies of the adsorbents followed the order of ACF10 > HD4000 > SWNT > MWNT, indicating that the availability of adsorption site was related to the pore size distributions of the adsorbents. ACF10 and HD4000 with higher microporous volumes exhibited higher adsorption affinities to low molecular weight AOCs than SWNT and MWNT with higher mesopore and macropore volumes. Due to their larger pore sizes, SWNTs and MWNTs are expected to be more efficient in adsorption of large size molecules. Removal of surface oxygen-containing functional groups from the SWNT enhanced adsorption of AOCs.

  10. Probing the dynamics of 3He atoms adsorbed on MCM-41 with pulsed NMR

    Science.gov (United States)

    Huan, C.; Masuhara, N.; Adams, J.; Lewkowitz, M.; Sullivan, N. S.

    2018-03-01

    We report measurements of the nuclear spin-spin and spin-lattice relaxation times for 3He adsorbed on MCM-41 for temperatures 0.08 < T < 1.2 K. Deviations from Curie behavior are observed at low temperatures. The relaxation times exhibit a two-component behavior representing the differing dynamics of the mobile quasi-free molecules in the center of the tubes compared to the adsorbed layer on the walls. The amplitudes of the two components provide an accurate measure of the number of fluid-like molecules traveling in the center of the nanotubes.

  11. Electron and photon-beam induced reactions of adsorbed disilane: Low-temperature thin-film growth

    International Nuclear Information System (INIS)

    Bozso, F.; Avouris, Ph.

    1991-01-01

    Electrons and photons of sufficient energy can cause fragmentation and desorption of adsorbed molecules or fragments of them, by inducing electronic excitations to dissociative states. The surface species after such excitations are mostly of highly reactive radical character, which readily react with the substrate and with other molecular or radical species in the adsorbed layer. This paper discusses the adsorption, thermal and electron/photon-beam induced reactions of disilane, oxygen and ammonia on Si(111)-7x7, and the electron/photon-induced growth of silicon, silicon dioxide and silicon nitride films at 100K

  12. Effective embedded-atom potential for metallic adsorbates on crystalline surfaces

    International Nuclear Information System (INIS)

    Förster, G D; Magnin, Y; Rabilloud, F; Calvo, F

    2014-01-01

    Based on the embedded-atom method (EAM), an analytical effective potential is developed to model the interaction of a metallic adsorbate on a perfect crystalline substrate, which is also metallic. The many-body character of the original EAM potential is preserved in the adsorbate energy and in the alteration of the substrate energy due to the presence of the adsorbate. A mean-field-type version neglecting corrugation of the substrate is first derived based on rigorous integration of individual monolayers, followed by an approximate form for the perturbation of the substrate energy. Lateral corrugation is subsequently included by additional phenomenological terms respecting the symmetry of the substrate, again preserving the many-body nature of the original potential. The effective model contains four parameters to describe uncorrugated substrates and eight extra parameters to describe every order of the Fourier lateral expansion. These parameters were fitted to reproduce the adsorption energy of a sample of random configurations of realistic 2D and 3D clusters deposited on the (1 1 1) fcc surface, for metals for which popular EAM models have been parametrized. As a simple application, the local relaxation of pre-formed icosahedral or truncated octahedral clusters soft-landed and exposing (1 1 1) faces in epitaxy to the substrate has been simulated at 0 and 300 K. The deformation of small clusters to wet the substrate is correctly captured by the effective model. This agreement with the exact potential suggests that the present model should be useful for treating metallic environments in large-scale surface studies, notably in structural optimization or as a template for more general models parametrized from ab initio data. (paper)

  13. Determinants of protein elution rates from preparative ion-exchange adsorbents.

    Science.gov (United States)

    Angelo, James M; Lenhoff, Abraham M

    2016-04-01

    The rate processes involved in elution in preparative chromatography can affect both peak resolution and hence selectivity as well as practical factors such as facility fit. These processes depend on the physical structure of the adsorbent particles, the amount of bound solute, the solution conditions for operation or some combination of these factors. Ion-exchange adsorbents modified with covalently attached or grafted polymer layers have become widely used in preparative chromatography. Their often easily accessible microstructures offer substantial binding capacities for biomolecules, but elution has sometimes been observed to be undesirably slow. In order to determine which physicochemical phenomena control elution behavior, commercially available cellulosic, dextran-grafted and unmodified agarose materials were characterized here by their elution profiles at various conditions, including different degrees of loading. Elution data were analyzed under the assumption of purely diffusion-limited control, including the role of pore structure properties such as porosity and tortuosity. In general, effective elution rates decreased with the reduction of accessible pore volume, but differences among different proteins indicated the roles of additional factors. Additional measurements and analysis, including the use of confocal laser scanning microscopy to observe elution within single chromatographic particles, indicated the importance of protein association within the particle during elution. The use of protein stabilizing agents was explored in systems presenting atypical elution behavior, and l-arginine and disaccharide excipients were shown to alleviate the effects for one protein, lysozyme, in the presence of sodium chloride. Incorporation of these excipients into eluent buffer gave rise to faster elution and significantly lower pool volumes in elution from polymer-modified adsorbents. Copyright © 2016 Elsevier B.V. All rights reserved.

  14. Development of a new adsorbent from agro-industrial waste and its potential use in endocrine disruptor compound removal.

    Science.gov (United States)

    Rovani, Suzimara; Censi, Monique T; Pedrotti, Sidnei L; Lima, Eder C; Cataluña, Renato; Fernandes, Andreia N

    2014-04-30

    A new activated carbon (AC) material was prepared by pyrolysis of a mixture of coffee grounds, eucalyptus sawdust, calcium hydroxide and soybean oil at 800°C. This material was used as adsorbent for the removal of the endocrine disruptor compounds 17β-estradiol (E2) and 17α-ethinylestradiol (EE2) from aqueous solutions. The carbon material was characterized by scanning electron microscopy (SEM), infrared spectroscopy (FTIR), N2 adsorption/desorption curves and point of zero charge (pHPZC). Variables including the initial pH of the adsorbate solutions, adsorbent masses and contact time were optimized. The optimum range of initial pH for removal of endocrine disruptor compounds (EDC) was 2.0-11.0. The kinetics of adsorption were investigated using general order, pseudo first-order and pseudo-second order kinetic models. The Sips isotherm model gave the best fits of the equilibrium data (298K). The maximum amounts of E2 and EE2 removed at 298K were 7.584 (E2) and 7.883mgg(-1) (EE2) using the AC as adsorbent. The carbon adsorbent was employed in SPE (solid phase extraction) of E2 and EE2 from aqueous solutions. Copyright © 2014 Elsevier B.V. All rights reserved.

  15. sup(60)Co hot atom chemistry of tris(acetylacetonato) cobalt(III) adsorbed on silica gel

    International Nuclear Information System (INIS)

    Nishioji, H.; Sakai, Y.; Tominaga, T.

    1985-01-01

    The sup(60)Co hot atom reactions were studied in tris(acetylacetonato)cobalt(III) adsorbed on silica gel surface. sup(57)Fe Moessbauer spectra of tris(acetylacetonato)iron(III) in the corresponding system were also measured in order to examine the state of dispersion of complex molecules on silica gel. The retention formation processes were discussed in terms of the dependence of sup(60)Co retention on the adsorbed amount (concentration) of cobalt(III) complexes. (author)

  16. Evaluation of a dehumidifier with adsorbent coated heat exchangers for tropical climate operations

    KAUST Repository

    Oh, Seung Jin; Ng, Kim Choon; Chun, Wongee; Chua, Kian Jon Ernest

    2017-01-01

    This paper presents the evaluation of a solid desiccant dehumidifier equipped with adsorbent powder coated heat exchangers (PCHX). The main component of the solid desiccant dehumidifier includes two heat exchangers that are coated with silica gel RD type powders in order to increase water adsorption uptake by improving its heat and mass transfer. A series of experiment are conducted to evaluate two key performance indices, namely, moisture removal capacity (MRC) and thermal coefficient performance (COPth), under various hot and humid air conditions. Conventional granular adsorbent packed heat exchangers (GPHX) are employed to benchmark the performance of the adsorbent coated heat exchanger (PCHX). Results reveal that the PCHX exhibits higher uptake performance due to better heat and mass transfer. It is found that the moisture removal capacity increases from 7.4 g/kg to 11.0 g/kg with air flow rates of 35 kg/h, resulting in the extended contact time of the water vapor. Experiments also demonstrate that the moisture removal capacity is highly affected by inlet air humidity ratio. In addition, marked improvement in COPth can be achieved by a lowered hot water regeneration temperature.

  17. Ordered mesoporous carbon coating on cordierite: Synthesis and application as an efficient adsorbent

    Energy Technology Data Exchange (ETDEWEB)

    Wan, Ying, E-mail: ywan@shnu.edu.cn [Key Laboratory of Resource Chemistry of Ministry of Education, Shanghai Key Laboratory of Rare Earth Functional Materials, Shanghai Normal University, Shanghai 200234 (China); Department of Chemistry, Shanghai Normal University, Shanghai 200234 (China); Cui, Xiangting; Wen, Zhentao [Department of Chemistry, Shanghai Normal University, Shanghai 200234 (China)

    2011-12-30

    Highlight: Black-Right-Pointing-Pointer Surfactant self-assembly of ordered mesoporous carbon coating on honeycomb cordierite. Black-Right-Pointing-Pointer Carbon coating with opened, hexagonally ordered pore arrays. Black-Right-Pointing-Pointer Honeycomb adsorbents for removal of p-chlorophenol. Black-Right-Pointing-Pointer The adsorbents exhibit large processing volume, and great advantages in reusability. - Abstract: Ordered mesoporous carbon coating on the honeycomb cordierite substrate has been prepared using low-polymerized phenolic resins as carbon sources and triblock copolymer F127 as the structure directing agent via the evaporation induced self-assembly route. The high-resolution scanning electron microscopy (HRSEM), transmission electron microscopy (TEM), and nitrogen sorption techniques prove the hexagonally ordered pore arrays of carbon coating on the cordierite. The honeycomb monolith adsorbents coated by ordered mesoporous carbons are directly used without any activation, and exhibit adsorption capacities for chlorinated organic pollutants in water with 200 mg/g for p-chlorophenol and 178 mg/g for p-chloroaniline (with respect to the net carbon coating), high adsorption ratio for low-concentration pollutants, large processing volumes and reusability. More than 200 repeated times can be achieved without obvious loss in both adsorption capacity and weight.

  18. Evaluation of a dehumidifier with adsorbent coated heat exchangers for tropical climate operations

    KAUST Repository

    Oh, Seung Jin

    2017-03-10

    This paper presents the evaluation of a solid desiccant dehumidifier equipped with adsorbent powder coated heat exchangers (PCHX). The main component of the solid desiccant dehumidifier includes two heat exchangers that are coated with silica gel RD type powders in order to increase water adsorption uptake by improving its heat and mass transfer. A series of experiment are conducted to evaluate two key performance indices, namely, moisture removal capacity (MRC) and thermal coefficient performance (COPth), under various hot and humid air conditions. Conventional granular adsorbent packed heat exchangers (GPHX) are employed to benchmark the performance of the adsorbent coated heat exchanger (PCHX). Results reveal that the PCHX exhibits higher uptake performance due to better heat and mass transfer. It is found that the moisture removal capacity increases from 7.4 g/kg to 11.0 g/kg with air flow rates of 35 kg/h, resulting in the extended contact time of the water vapor. Experiments also demonstrate that the moisture removal capacity is highly affected by inlet air humidity ratio. In addition, marked improvement in COPth can be achieved by a lowered hot water regeneration temperature.

  19. Utilization of granular activated carbon adsorber for nitrates removal from groundwater of the Cluj region.

    Science.gov (United States)

    Moşneag, Silvia C; Popescu, Violeta; Dinescu, Adrian; Borodi, George

    2013-01-01

    The level of nitrates from groundwater from Cluj County and other areas from Romania have increased values, exceeding or getting close to the allowed limit values, putting in danger human and animal heath. In this study we used granular activated carbon adsorbent (GAC) for nitrate (NO(-)3) removal for the production of drinking water from groundwater of the Cluj county. The influences of the contact time, nitrate initial concentration, and adsorbent concentration have been studied. We determined the equilibrium adsorption capacity of GAC, used for NO(-)3 removal and we applied the Langmuir and Freundlich isotherm models. Ultraviolet-visible (UV-Vis) and Fourier transform infrared (FTIR) spectroscopy, X ray diffraction (XRD), Scanning Electron Microscopy (SEM) were used for process characterization. We also determined: pH, conductivity, Total Dissolved Solids and Total Hardness. The GAC adsorbents have excellent capacities of removing nitrate from groundwater from Cluj County areas.

  20. Coconut coir dust as a low cost adsorbent for the removal of cationic dye from aqueous solution

    Directory of Open Access Journals (Sweden)

    U.J. Etim

    2016-09-01

    Full Text Available Adsorption of methylene blue from aqueous solution onto coconut coir dust (CCD a low cost agricultural waste material in a batch process was investigated. Adsorption was studied as a function of amount of adsorbent, pH and concentration with time. It was found that percentage adsorption varied linearly with the amount of adsorbent and concentration with time but varies non-linearly with pH. Adsorption equilibrium data were represented by isotherm, kinetics and thermodynamics models. Three isotherm models namely Langmuir, Freundlich and Temkin were tested and adsorption was found to fit well into these models with R2 ⩾ 0.90. The kinetic data were well described by the pseudo-second order kinetic model. The adsorption process was endothermic with a mean change in enthalpy (ΔH (+17.87 KJ mol−1 and spontaneous with a mean free energy change (ΔG (−9.69 KJ mol−1. FTIR analyses of the adsorbent suggest that adsorption of the dye was through a chemical interaction of the functional groups on the surface of the adsorbent.