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Sample records for adsorptive properties

  1. Adsorption Properties of Chalk Reservoir Materials

    DEFF Research Database (Denmark)

    Okhrimenko, Denis

    Understanding adsorption energetics and wetting properties of calcium carbonate surfaces is essential for developing remediation strategies for aquifers, improving oil recovery, minimising risk in CO2 storage and optimising industrial processes. This PhD was focussed on comparing the vapour....../gas adsorption properties of synthetic calcium carbonate phases (calcite, vaterite and aragonite) with chalk, which is composed of biogenic calcite (>98%). In combination with data from nanotechniques, the results demonstrate the complexity of chalk behavior and the role of nanoscale clay particles. The results...

  2. PREPARATION OF ACTIVATED CARBON FIBER AND THEIR XENON ADSORPTION PROPERTIES (Ⅱ)-XENON ADSORPTION PROPERTIES

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    The adsorption of xenon from air has an interest in the monitoring of nuclear explosion oraccident, or in the treatment of nuclear waste gas. In this paper, the pore structure of several series ofactivated carbon fibers has been characterized. The adsorption properties of xenon on theseactivated carbon fibers under different temperatures have been studied in details. The results showthat the xenon adsorption amount on activated carbon fibers do not increase with specific surfacearea of adsorbents, but are closely related to their pore size distribution. Pores whose radius equal toor narrow than 0.4nm would be more advantageous to the adsorption of xenon.

  3. Adsorption properties of nitrobenzene in wastewater with silica aerogels

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    The adsorption properties of nitrobenzene from wastewater by hydrophobic silica aerogels were investigated.The effects of adsorption intensity by pH value,adsorption temperature,adsorption time and the amount of the silica aerogels were studied.The adsorption principle and mechanism of silica aerogels adsorbing nitrobenzene were discussed along with the Freundlich equation.The results showed that the adsorption intensity of the hydrophobic silica aerogels could reach 68.76% at better adsorption conditions of adsorption temperature 25°C,pH value 8.35,the amount of SiO2 aerogels dosage 3.33 g/L,and adsorption time of 30 min,and that the adsorption properties were related to the hydrophobility of aerogels,surface area of organic solution,structure of aerogels.

  4. Assessing the adsorption properties of shales

    Science.gov (United States)

    Pini, Ronny

    2015-04-01

    Physical adsorption refers to the trapping of fluid molecules at near liquid-like densities in the pores of a given adsorbent material. Fine-grained rocks, such as shales, contain a significant amount of nanopores that can significantly contribute to their storage capacity. As a matter of fact, the current ability to extract natural gas that is adsorbed in the rock's matrix is limited, and current technology focuses primarily on the free gas in the fractures (either natural or stimulated), thus leading to recovery efficiencies that are very low. Shales constitute also a great portion of so-called cap-rocks above potential CO2 sequestration sites; hereby, the adsorption process may limit the CO2 mobility within the cap-rock, thus minimizing the impact of leakage on the whole operation. Whether it is an unconventional reservoir or a cap-rock, understanding and quantifying the mechanisms of adsorption in these natural materials is key to improve the engineering design of subsurface operations. Results will be presented from a laboratory study that combines conventional techniques for the measurement of adsorption isotherms with novel methods that allows for the imaging of adsorption using x-rays. Various nanoporous materials are considered, thus including rocks, such as shales and coals, pure clay minerals (a major component in mudrocks) and engineered adsorbents with well-defined nanopore structures, such as zeolites. Supercritical CO2 adsorption isotherms have been measured with a Rubotherm Magnetic Suspension balance by covering the pressure range 0.1-20~MPa. A medical x-ray CT scanner has been used to identify three-dimensional patterns of the adsorption properties of a packed-bed of adsorbent, thus enabling to assess the spatial variability of the adsorption isotherm in heterogeneous materials. The data are analyzed by using thermodynamically rigorous measures of adsorption, such as the net- and excess adsorbed amounts and a recently developed methodology is

  5. Development of facile property calculation model for adsorption chillers based on equilibrium adsorption cycle

    Science.gov (United States)

    Yano, Masato; Hirose, Kenji; Yoshikawa, Minoru; Thermal management technology Team

    Facile property calculation model for adsorption chillers was developed based on equilibrium adsorption cycles. Adsorption chillers are one of promising systems that can use heat energy efficiently because adsorption chillers can generate cooling energy using relatively low temperature heat energy. Properties of adsorption chillers are determined by heat source temperatures, adsorption/desorption properties of adsorbent, and kinetics such as heat transfer rate and adsorption/desorption rate etc. In our model, dependence of adsorption chiller properties on heat source temperatures was represented using approximated equilibrium adsorption cycles instead of solving conventional time-dependent differential equations for temperature changes. In addition to equilibrium cycle calculations, we calculated time constants for temperature changes as functions of heat source temperatures, which represent differences between equilibrium cycles and real cycles that stemmed from kinetic adsorption processes. We found that the present approximated equilibrium model could calculate properties of adsorption chillers (driving energies, cooling energies, and COP etc.) under various driving conditions quickly and accurately within average errors of 6% compared to experimental data.

  6. Acoustic and adsorption properties of submerged wood

    Science.gov (United States)

    Hilde, Calvin Patrick

    Wood is a common material for the manufacture of many products. Submerged wood, in particular, is used in niche markets, such as the creation of musical instruments. An initial study performed on submerged wood from Ootsa Lake, British Columbia, provided results that showed that the wood was not suitable for musical instruments. This thesis re-examined the submerged wood samples. After allowing the wood to age unabated in a laboratory setting, the wood was retested under the hypothesis that the physical acoustic characteristics would improve. It was shown, however, that the acoustic properties became less adequate after being left to sit. The adsorption properties of the submerged wood were examined to show that the submerged wood had a larger accessible area of wood than that of control wood samples. This implied a lower amount of crystalline area within the submerged wood. From the combined adsorption and acoustic data for the submerged wood, relationships between the moisture content and speed of sound were created and combined with previous research to create a proposed model to describe how the speed of sound varies with temperature, moisture content and the moisture content corresponding to complete hydration of sorption sites within the wood.

  7. Influences of Soluble Salts on Adsorption Properties of Polycarboxylate Superplasticizers

    Institute of Scientific and Technical Information of China (English)

    WANG Dongmin; CHENG Peifu; XIONG Weifeng; SONG Taowen; WU Zengli

    2012-01-01

    Polycarboxylate (PC) superplasticizers with different chemical structures were synthesized through free radical co-polymerization reaction.A total organic carbon analyzer was used to investigate adsorption behaviors of PCs,and to evaluate influences of soluble salts on absorption properties of PCs.It is found that adsorption ratios of PCs on cement particles decrease greatly with the addition of Na2SO4; the adsorption ratio of ethers PC with Hydroxyethyl methacrylate (HEMA) group first increases then decreases with the addition of NaCl; the adsorption ratio of esters PC with short side chains first decreases then increases,while the adsorption ratio of ethers PC with HEMA group decreases with the addition of CaCl2; the adsorption ratio of esters PC with short side chains decreases with the addition of Ca(NO3)2; AlCl3 causes the decrease of the adsorption ratio of ethers PC with HEMA group.

  8. Adsorptive property of rice husk for uranium

    International Nuclear Information System (INIS)

    The adsorption experiments were researched by using the rice husk powder as the adsorbent to remove the U(VI) from aqueous solution. The affecting factors on the U(VI) removal rate such as rice husk particle size, pH, initial concentration, adsorption time, temperature and dosage of adsorbent were evaluated, kinetics and adsorption isotherm law were analyzed, and mechanisms for U(VI) removal were discussed by SEM, FT-IR and energy spectrum analysis. The results show that U(VI) removal rate increases with the decrease of the size of adsorbent, and with the increase of adsorbent dosage and temperature. The process of adsorption can be described by an equation of pseudo 2nd-order mode, and the relation coefficient is 1. The process of adsorption also fits to Freundlich isotherm (R2=0.995 4). The adsorption of uranium on rice husk changes the surface form of rice husk. Hydroxyl, carboxylic, P-O and Si-O are the main functional groups in the reaction with U(VI). The adsorption mechanism is mixture adsorption, including the physical and chemical adsorption. (authors)

  9. Tailoring fibre and paper properties using physical adsorption of polyelectrolytes

    OpenAIRE

    Marais, Andrew

    2012-01-01

    The adsorption of polyelectrolytes, both as monolayers and as multilayers, was investigated as an easy and non-expensive way of producing lignocellulosic fibrous materials with enhanced mechanical properties. In the first part of the work described in this thesis, the adsorption of a polyelectrolyte monolayer onto the surface of unbleached and unbeaten kraft pulp fibres with different kappa numbers was investigated. Adsorption isotherms were obtained in order to determine the amounts of polym...

  10. Adsorption properties of GaAs-CdS system

    International Nuclear Information System (INIS)

    The adsorption properties of GaAs-CdS solid solutions and the constituent binary systems with respect to CO and NH3 were studied by piezoquartz microweighing, temperature-programmed desorption, and IR spectroscopy. On the basis of an analysis of the measured αp=f(T), αT=f (p), and αT=f (t) dependences, the thermodynamic and kinetic characteristics of adsorption, earlier obtained acid-base and other physicochemical characteristics of adsorbents, and the electronic properties of the adsorbate molecules, the mechanism and regularities of the adsorption processes at various conditions and compositions of the system were established. A comparison of the adsorption properties of the GaAs and CdS individual binary compounds with their (GaAs)x(CdS)1-x solutions, multicomponent systems, revealed common and distinctive features. Optimal compositions of adsorbents suitable for manufacturing primary transducers in sensors for medical and environmental purposes were determined

  11. Adsorption Properties of the Cu(115) Surface

    DEFF Research Database (Denmark)

    Godowski, P. J.; Groso, A.; Hoffmann, S. V.; Onsgaard, Jens

    2010-01-01

    curve has been confirmed as a very convenient and precise procedure. The adsorbed state of CO at 130 K has been identified by registration of core levels obtained by the use synchrotron radiation photoelectron spectroscopy. The characteristics of the main is and satellite peaks have been analyzed in...... context of substrate geometry and compared with the ones of other copper planes. There are no indications of dissociative adsorption of CO, only residual carbon and oxygen were found after adsorbate desorption around 220 K. CO molecules show a strong tendency to "on top" adsorption in sites far from the...

  12. Controlled swelling and adsorption properties of polyacrylate/montmorillonite composites

    Energy Technology Data Exchange (ETDEWEB)

    Natkanski, Piotr [Faculty of Chemistry, Jagiellonian University, Ingardena 3, 30-060 Krakow (Poland); Kustrowski, Piotr, E-mail: kustrows@chemia.uj.edu.pl [Faculty of Chemistry, Jagiellonian University, Ingardena 3, 30-060 Krakow (Poland); Bialas, Anna; Piwowarska, Zofia [Faculty of Chemistry, Jagiellonian University, Ingardena 3, 30-060 Krakow (Poland); Michalik, Marek [Institute of Geological Sciences, Jagiellonian University, Oleandry 2a, 30-063 Krakow (Poland)

    2012-10-15

    A series of novel polyacrylate/montmorillonite composites was synthesized by in situ polymerization in aqueous slurry of clay. Dissociated (obtained by adding ammonium or sodium hydroxide) and undissociated forms of acrylic acid were used as monomers in the hydrogel synthesis. The structure and composition of the samples were studied by powder X-ray diffraction, diffuse reflectance infra-red Fourier transform spectroscopy, thermogravimetry and elemental analysis. It has been found that the kind of monomer influences strongly the location of a polymer chain in the formed composite. Complete intercalation of hydrogel into the interlayer space of montmorillonite was observed for sodium polyacrylate, whereas polyacrylic acid and ammonium polyacrylate mainly occupied the outer surface of the clay. The position of hydrogel determined the swelling and adsorption properties of the studied composites. The important factor influencing the kinetics of Fe(III) cation adsorption was pH. The analysis of adsorption isotherms allowed to propose the mechanism of Fe(III) cation adsorption. Highlights: Black-Right-Pointing-Pointer Polyacrylate hydrogels can be introduced into the interlayers of clay. Black-Right-Pointing-Pointer The position of hydrogel in the composite depends on the polymer type. Black-Right-Pointing-Pointer Ammonium polyacrylate places outside the clay, sodium one is intercalated into it. Black-Right-Pointing-Pointer Swelling and adsorption capacities can be controlled by the polymer position. Black-Right-Pointing-Pointer High adsorption efficiency in Fe(III) removal was observed.

  13. Adsorption Properties of Lignin-derived Activated Carbon Fibers (LACF)

    Energy Technology Data Exchange (ETDEWEB)

    Contescu, Cristian I. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Gallego, Nidia C. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Thibaud-Erkey, Catherine [United Technologies Research Center (UTRC), East Hartford, CT (United States); Karra, Reddy [United Technologies Research Center (UTRC), East Hartford, CT (United States)

    2016-04-01

    The object of this CRADA project between Oak Ridge National Laboratory (ORNL) and United Technologies Research Center (UTRC) is the characterization of lignin-derived activated carbon fibers (LACF) and determination of their adsorption properties for volatile organic compounds (VOC). Carbon fibers from lignin raw materials were manufactured at Oak Ridge National Laboratory (ORNL) using the technology previously developed at ORNL. These fibers were physically activated at ORNL using various activation conditions, and their surface area and pore-size distribution were characterized by gas adsorption. Based on these properties, ORNL did down-select five differently activated LACF materials that were delivered to UTRC for measurement of VOC adsorption properties. UTRC used standard techniques based on breakthrough curves to measure and determine the adsorption properties of indoor air pollutants (IAP) - namely formaldehyde and carbon dioxide - and to verify the extent of saturated fiber regenerability by thermal treatments. The results are summarized as follows: (1) ORNL demonstrated that physical activation of lignin-derived carbon fibers can be tailored to obtain LACF with surface areas and pore size distributions matching the properties of activated carbon fibers obtained from more expensive, fossil-fuel precursors; (2) UTRC investigated the LACF potential for use in air cleaning applications currently pursued by UTRC, such as building ventilation, and demonstrated their regenerability for CO2 and formaldehyde, (3) Both partners agree that LACF have potential for possible use in air cleaning applications.

  14. Porous and adsorption properties of hydrated cement paste

    Directory of Open Access Journals (Sweden)

    Marina Biljana S.

    2004-01-01

    Full Text Available Adsorption isotherms of benzene on hydrated cement pastes prepared by cement ground with and without the addition of grinding aids, triethanol amine (TEA and ethylene glycol (EG were investigated. The adsorption isotherms were interpreted by means of the Dubinin-Astakhov (DA and Dubinin-Radushkevich-Stoeckli (DRS equations. The microporous structure of cement gel (C-S-H in the cement pastes, and changes in the Gibbs free energy of adsorption were determined. The mechanical properties of the cement pastes were also measured. It was evident that pastes with additives had different parameters of the DRS and DA equations: the volume and dimensions of the gel pores, the distribution of the dimensions, the characteristic energy of adsorption, and the change in the Gibbs free energy of adsorption. The mechanical properties were also different. The dispersity of the additive-containing ground cements had a favorable effect on the hydration processes. When applying TEA, it was also necessary to analyze its influence on the chemical behavior of hydration in the starting period.

  15. Adsorption properties of the SAPO-5 molecular sieve

    KAUST Repository

    Hu, Enping

    2010-09-09

    The adsorption properties of an aluminophosphate molecular sieve, SAPO-5, were measured for a number of gases and vapors, including N2, water, isopropanol, and xylenes. The data showed that SAPO-5 is quite hydrophobic and has a strong selectivity of o-xylene over its isomers m- and p-xylene. © 2010 American Chemical Society.

  16. Impact of soil properties on selected pharmaceuticals adsorption in soils

    Science.gov (United States)

    Kodesova, Radka; Kocarek, Martin; Klement, Ales; Fer, Miroslav; Golovko, Oksana; Grabic, Roman; Jaksik, Ondrej

    2014-05-01

    The presence of human and veterinary pharmaceuticals in the environment has been recognized as a potential threat. Pharmaceuticals may contaminate soils and consequently surface and groundwater. Study was therefore focused on the evaluation of selected pharmaceuticals adsorption in soils, as one of the parameters, which are necessary to know when assessing contaminant transport in soils. The goals of this study were: (1) to select representative soils of the Czech Republic and to measure soil physical and chemical properties; (2) to measure adsorption isotherms of selected pharmaceuticals; (3) to evaluate impact of soil properties on pharmaceutical adsorptions and to propose pedotransfer rules for estimating adsorption coefficients from the measured soil properties. Batch sorption tests were performed for 6 selected pharmaceuticals (beta blockers Atenolol and Metoprolol, anticonvulsant Carbamazepin, and antibiotics Clarithromycin, Trimetoprim and Sulfamethoxazol) and 13 representative soils (soil samples from surface horizons of 11 different soil types and 2 substrates). The Freundlich equations were used to describe adsorption isotherms. The simple correlations between measured physical and chemical soil properties (soil particle density, soil texture, oxidable organic carbon content, CaCO3 content, pH_H2O, pH_KCl, exchangeable acidity, cation exchange capacity, hydrolytic acidity, basic cation saturation, sorption complex saturation, salinity), and the Freundlich adsorption coefficients were assessed using Pearson correlation coefficient. Then multiple-linear regressions were applied to predict the Freundlich adsorption coefficients from measured soil properties. The largest adsorption was measured for Clarithromycin (average value of 227.1) and decreased as follows: Trimetoprim (22.5), Metoprolol (9.0), Atenolol (6.6), Carbamazepin (2.7), Sulfamethoxazol (1.9). Absorption coefficients for Atenolol and Metoprolol closely correlated (R=0.85), and both were also

  17. Adsorption Properties of Adsorption Tower Filled with Calcium Superphosphate on NH3 Emitted from Composting System of Animal Wastes

    Institute of Scientific and Technical Information of China (English)

    Dandan LUI; Yunxiao CHONG; Qitang WU; Genyi WU; Dechun HE; Jinrong QIU; Zhencheng XU

    2012-01-01

    [Objective] This study aimed to investigate the adsorption properties of the adsorption tower filled with calcium superphosphate on ammonia volatilized with aer- ation. [Method] Adsorption tower filled with calcium superphosphate was adopted as experimental apparatus, which was constructed by poly vinyl chloride (PVC) circular tubes. With hartshorn as the source of ammonia volatilization, the effect of different ratios of height to diameter of the tower filled with equal amount of calcium super-phosphate on ammonia adsorption was investigated. In addition, adsorption tower with height-diameter ratio of 9.9 was selected to adsorb the ammonia emitted from the composting systems of pig manure and chicken manure with optimized and reg- ulated carbon-nitrogen ratio. [Result] Under certain volatilization rate, calcium super- phosphate particles in the adsorption tower could effectively adsorb the ammonia, and the adsorption efficiency was enhanced with the increase of height-diameter ra-tio, which could reach above 90% with height-diameter ratio of more than 1.1; the ammonia emitted from composting systems of pig manure and chicken manure with optimized and regulated carbon-nitrogen ratio could be completely absorbed using adsorption tower with height-diameter ratio of 9.9 filled with calcium superphosphate accounting for about 8% of the weight of composting materials. [Conclusion] Experi- mental results of this study provided reference for the application of adsorption tower filled with calcium superphosphate in the treatment of waste gas emitted from com- posting materials.

  18. Cadmium adsorption by coal combustion ashes-based sorbents-Relationship between sorbent properties and adsorption capacity

    International Nuclear Information System (INIS)

    A very interesting possibility of coal combustion ashes reutilization is their use as adsorbent materials, that can also take advantage from proper beneficiation techniques. In this work, adsorption of cadmium from aqueous solutions was taken into consideration, with the emphasis on the intertwining among waste properties, beneficiation treatments, properties of the beneficiated materials and adsorption capacity. The characterization of three solid materials used as cadmium sorbents (as-received ash, ash sieved through a 25 μm-size sieve and demineralized ash) was carried out by chemical analysis, infrared spectroscopy, laser granulometry and mercury porosimetry. Cadmium adsorption thermodynamic and kinetic tests were conducted at room temperature, and test solutions were analyzed by atomic absorption spectrophotometry. Maximum specific adsorption capacities resulted in the range 0.5-4.3 mg g-1. Different existing models were critically considered to find out an interpretation of the controlling mechanism for adsorption kinetics. In particular, it was observed that for lower surface coverage the adsorption rate is governed by a linear driving force while, once surface coverage becomes significant, mechanisms such as the intraparticle micropore diffusion may come into play. Moreover, it was shown that both external fluid-to-particle mass transfer and macropore diffusion hardly affect the adsorption process, which was instead regulated by intraparticle micropore diffusion: characteristic times for this process ranged from 4.1 to 6.1 d, and were fully consistent with the experimentally observed equilibrium times. Results were discussed in terms of the relationship among properties of beneficiated materials and cadmium adsorption capacity. Results shed light on interesting correlations among solid properties, cadmium capture rate and maximum cadmium uptake.

  19. Oxygen Storage Capacity and Adsorptive Property of Praseodymium Oxides

    Institute of Scientific and Technical Information of China (English)

    万颖; 马建新; 方明; 刘毅廷

    2003-01-01

    Oxygen storage and adsorptive properties of praseodymium oxides were investigated by pulse experiments and temperature-programmed desportion/reduction (TPD/TPR) experiments. Pr2O3 possesses the similar oxygen storage properties to CeO 2, and its dynamic oxygen storage capacity is 14.9 μmolg-1. The studies on TPD of O2, H2O and CO and TPR show that Pr2O3 provides more active sur face oxygen species and at a lower temperature than CeO2. It is suggested that Pr2O3 can be a well candidate as an oxygen storage component in automobile three-way catalyst.

  20. Synthesis and adsorption properties of chitosan-crown ether resins

    Institute of Scientific and Technical Information of China (English)

    彭长宏; 陈艺锋; 唐谟堂

    2003-01-01

    Two kinds of novel chitosan-crown ether resins, Schiff base type chitosan-benzo-15-crown-5 (CTS-B15)and chitosan-benzo-18-crown-6 (CTS-B18), were synthesized through the reaction between -NH2 in chitosan and -CHO in 4′-formyl benzo-crown ethers. Their structures were characterized by elemental analysis and FT-IR spectra analysis. The elemental analysis results show that the mass fractions of nitrogen in CTS-B15 and CTS-B18 are much lower than those of chitosan. The results of FT-IR spectra of CTS-B15 and CTS-B18 reveal that there exist characteristic peak of C= N, N-H and Ar, and characteristic peak of pyr anoside in the chain of chitosan-crown ether resins, showing that the structures of chitosan-crown ethers are as expected. The adsorption properties of CTS-B15 and CTS-B18 for Pd2+ , Cu2 + and Hg2+ were studied and the experimental results show that these adsorbents have both good adsorption characterization and especially high particular adsorption selectivity for Pd2+ when Cu2+ and Hg2+ are in coexistence, and the coefficients of selectivity of CTS-B15 and CTS-B18 for metal ions are KPd2+/cu2+ =7.56, KPd2+/Hg2+ = 68.00, Kcu2+/Hg2+ = 9.00 and KPd2+/cu2+ = 6.00, KPd2+/Hg2+ = 19. 00, Kcu2+/Hg2+ = 3.00, respectively.

  1. Influence of adsorption properties on radionuclide transport in fractured rock

    International Nuclear Information System (INIS)

    Most models predicting radionuclide transport in fractured rock include mechanisms of advection, dispersion, radioactive decay, and equilibrium adsorption between the solid and liquid phases. Recently, nonequilibrium adsorption has been given a great deal of attention. In this paper, the authors have successfully derived the analytical solutions to transport equations for a single fracture under various conditions covering no sorption, nonequilibrium adsorption, and equilibrium sorption

  2. Adsorption properties of leather modified by radiation induced grafting with methyl methacrylate and butyl acrylate

    International Nuclear Information System (INIS)

    Adsorption properties of leathers modified by radiation induced grafting with butyl acrylate and methyl methacrylate have been investigated by the McBain method. Isotherms of adsorption and desorption of water vapour have been obtained and the specific surface for various leathers calculated. No change in the adsorption properties of modified leather was noticed up to 25% content of grafted polymer. At higher polymer content deterioration of hygienic properties of modified leather was observed. From the adsorption measurements it has been concluded that the size of millipores undergoes random distribution and no specific group of pores prevails. Explanation of the observed phenomena is proposed. (author)

  3. Synthesis of amidoxime chelating fiber and its adsorption properties for Cu(II) ion

    International Nuclear Information System (INIS)

    In order to obtain the chelating fiber for adsorbing metal ions in apple juice, the effect of different conditions on adsorption properties of chelating fiber for Cu(II) ion were discussed, such as pH and the time of ad- sorption. The isotherm of adsorption has bee confirmed. The desorption and its regeneration were simply discussed, too. The results showed that the chelating fiber had good kinetic property and the adsorbed equilibrium completed almost within 20-30 min. The adsorption properties was affected by the temperature and pH. The adsorption process fits the isothermal equation of Freundlich. The chelating fiber could be used repeatedly. (authors)

  4. Adsorption properties of a natural zeolite-water pair for use in adsorption cooling cycles

    Energy Technology Data Exchange (ETDEWEB)

    Solmus, ismail; Yamali, Cemil; Baker, Derek; Caglar, Ahmet [Department of Mechanical Engineering, Middle East Technical University, 06531 Ankara (Turkey); Kaftanoglu, Bilgin [Department of Manufacturing Engineering, Atilim University, 06836 Ankara (Turkey)

    2010-06-15

    The equilibrium adsorption capacity of water on a natural zeolite has been experimentally determined at different zeolite temperatures and water vapor pressures for use in an adsorption cooling system. The Dubinin-Astakhov adsorption equilibrium model is fitted to experimental data with an acceptable error limit. Separate correlations are obtained for adsorption and desorption processes as well as a single correlation to model both processes. The isosteric heat of adsorption of water on zeolite has been calculated using the Clausius-Clapeyron equation as a function of adsorption capacity. The cyclic adsorption capacity swing for different condenser, evaporator and adsorbent temperatures is compared with that for the following adsorbent-refrigerant pairs: activated carbon-methanol; silica gel-water; and, zeolite 13X-water. Experimental results show that the maximum adsorption capacity of natural zeolite is nearly 0.12 kg{sub w}/kg{sub ad} for zeolite temperatures and water vapor pressures in the range 40-150 C and 0.87-7.38 kPa. (author)

  5. Preparation of titanium peroxide and its selective adsorption property on cationic dyes

    International Nuclear Information System (INIS)

    Titanium peroxide powder was prepared with the reaction of titanium sulfate and H2O2 and showed good selective adsorption property on cationic dyes. The obtained material was characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FT-IR), X-ray photoelectron spectroscopy (XPS) and thermogravimetric and differential scanning calorimetry (TG-DSC). The selective adsorption property was confirmed and evaluated by adsorption experiments of methyl orange (MO), phenol and three kinds of cationic dyes including methylene blue (MB), malachite green (MG) and neutral red (NR). The adsorption was very fast and adsorption equilibrium was reached in a very short time for all three cationic dyes. The adsorption kinetics of MB, MG and NR were studied then. It was found that the adsorption data fitted perfectly with the pseudo-second-order kinetics and the saturated adsorption capacities for MB, MG and NR were 224.37, 251.38 and 327.61 mg/g at 25 °C, respectively. The characterization and adsorption results indicated the controlling mechanism of adsorption processes could be electrostatic adsorption.

  6. Adsorption and correlation with their thermodynamic properties of triazine herbicides on soils

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    Adsorption of atrazine, prometryne and prometon was determined on six soils with different physical and chemical properties. Theadsorption isotherms of three herbicides could well fit Freundlich equation. On all of six soils, adsorption of herbicides increased in the order:atrazine ≈ prometon < prometryne. This order is quite the same to the calculation result of by means of excess thermodynamic properties oftriazine. The Freundlich adsorption constants, Kf, showed to have good correlation with organic matter(OM%) of soils for each of theseherbicides, suggesting that OM is the main factor, which dominates in the adsorption process of these triazine herbicides.

  7. Preparation and adsorption property of aminated cross linking microbeads of GMA/EGDMA for bilirubin

    Indian Academy of Sciences (India)

    Zhiping Chen; Baojiao Gao; Xiaofeng Yang

    2009-11-01

    Cross linking microbeads with a controllable diameter were synthesized by suspension copolymerization of the monomer glycidyl methacrylate (GMA) and the cross linking agent ethylene glycol dimethylacrylate (EGDMA). By the ring-opening reaction of the epoxy groups, the microbeads GMA/EGDMA were modified with different aminating agents and resulting in the aminated microbeads. The morphology of the microbeads was characterized by SEM. The adsorption property of aminated microbeads for bilirubin was investigated, and the effects of various factors, such as the chemical structures of the aminating agents, pH values of the medium and the presence of bovine serum albumin in the adsorption medium, on the adsorption property were examined. The experimental results show that the aminated microbeads have strong adsorption ability for bilirubin, and the isotherm adsorption behaviour is fitted to Freundlich equation satisfactorily. The adsorption ability of the aminated microbeads modified with hexanediamine is stronger than that of others, and the longer the molecule of multi-ethylene multiamine, the weaker the adsorption ability for bilirubin. The pH value of the medium affects the adsorption ability greatly, as pH = 6, the adsorption ability is strongest. In the presence of BSA, the microbeads still have a higher adsorption capacity towards bilirubin.

  8. Pd and Au nanoparticles on different oxide supports - stability and CO adsorption properties

    OpenAIRE

    Höbel, F.

    2008-01-01

    In this study, the structure and adsorption properties of oxide supported model catalyst surfaces were investigated on a microscopic level using a comprehensive set of surface science techniques. Specifically, molecular CO adsorption on well-defined model catalyst surfaces has been studied in a broad temperature and pressure regime. As a result, the study enabled one to gain a fundamental understanding on the relation between the microscopic structure of the model catalyst and its adsorption ...

  9. Gyroidal nanoporous carbons - Adsorption and separation properties explored using computer simulations

    OpenAIRE

    Furmaniak, S.; Gauden, P. A.; Terzyk, A. P.; Kowalczyk, P.

    2016-01-01

    Adsorption and separation properties of gyroidal nanoporous carbons (GNCs) - a new class of exotic nanocarbon materials are studied for the first time using hyper parallel tempering Monte Carlo Simulation technique. Porous structure of GNC models is evaluated by the method proposed by Bhattacharya and Gubbins. All the studied structures are strictly microporous. Next, mechanisms of Ar adsorption are described basing on the analysis of adsorption isotherms, enthalpy plots, the values of Henry'...

  10. Preparation and adsorption properties of macroporous tannin resins

    Institute of Scientific and Technical Information of China (English)

    Zhang Li-ping; Du Jie; Liu Jian

    2006-01-01

    In this paper, a new kind of adsorption resin with multi-phenolic hydroxyl was created by immobilizing black wattle bark tannins to chloromethyl polystyrene resin. Its adsorption capacity to cation dye was tested. With an orthogonal test the optimal conditions of synthesis were determined: the concentration of sodium hydroxide solution 1.0 mol·L-1; the reaction time is one hour and the mass concentration of tannins 5%. With single factorial experiment the optimal conditions of adsorption were confirmed: a solidified pH of 5.0; an adsorption temperature of 25℃ and a cation dye concentration of 100 mg·L-1. The adsorption for cation dye can be similar to Langmuir isotherms.

  11. Synthesis and Adsorption Property of Dihydroxyl Azacrown Ether—Grafted Chitosan

    Institute of Scientific and Technical Information of China (English)

    ZhiKuanYANG; LiZHUANG; 等

    2002-01-01

    A novel dihydroxyl azacrown ether chitosan was synthesized by reacting dihydroxyl azacrown ether with epoxy activated chitosan. The adsorption property of the azacrown ether chitosan for Pb2+, Cr3+, and Ag+, were determined. The experimental results showed that the dihydroxyl azacrown ether grafted chitosan has high adsorption capacity and high selectivity for some metal ions.

  12. Synthesis and Adsorption Property of Dihydroxyl Azacrown Ether-Grafted Chitosan

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    A novel dihydroxyl azacrown ether chitosan was synthesized by reacting dihydroxyl azacrown ether with epoxy activated chitosan. The adsorption property of the azacrown ether chitosan for Pb2+, Cr3+, and Ag+, were determined. The experimental results showed that the dihydroxyl azacrown ether grafted chitosan has high adsorption capacity and high selectivity for some metal ions.

  13. Mesoporous hydroxyapatite: Preparation, drug adsorption, and release properties

    International Nuclear Information System (INIS)

    Mesoporous hydroxyapatite (HA) was synthesized through gas–liquid chemical precipitation method at ambient temperature without any template. Structure, morphology and pore size distribution of HA were analyzed via X-ray powder diffraction, scanning electron microscopy, transmission electron microscopy, high-resolution electron microscopy and N2 adsorption/desorption. The chemotherapeutic agent doxorubicin (DOX) was used to investigate the drug adsorption and release behavior of HA. The kinetics of DOX adsorption on HA followed the pseudo-second-order rate expression. Adsorption isotherms at various temperatures were obtained, and the equilibrium data fitted the Langmuir model. The values of thermodynamic parameters (Gibbs free energy, entropy, and enthalpy changes) demonstrated that the adsorption process was spontaneous and endothermic. In vitro pH-responsive (pH = 7.4, 5.8) controlled release was investigated. DOX-loaded HA showed a slow, long-term, and steady release rate. The release rate at pH5.8 was larger than that at pH7.4. Consequently, the as-prepared mesoporous HA has potential applications in controlled drug delivery systems. - Highlights: • Mesoporous HA was synthesized by a simple precipitation method without any template. • The kinetics of adsorption followed the pseudo-second-order rate expression. • Thermodynamics investigation showed that adsorption was spontaneous and endothermic. • DOX-loaded HA showed a long-term, steady, and pH-controlled release rate

  14. Adsorption Properties of Chromium (VI by Chitosan Coated Montmorillonite

    Directory of Open Access Journals (Sweden)

    Dahe Fan

    2006-01-01

    Full Text Available The adsorption of chromium (VI by Chitosan Coated Montmorillonite (CCM from aqueous solution was studied. To evaluate the adsorption capacity, the effects of pH, initial concentration and temperature on the adsorption were investigated. The isothermal data was applied to Langmuir linear and the Freundlich linear isotherm equation and the thermodynamic parameters (ΔH, ΔG, ΔS were calculated according to the values of binding Langmuir constant, KL. Results indicated that the adsorption between CCM and chromium (VI was significantly physical, the negative ΔH constant at lower temperature confirmed that the more chromium (VI was adsorbed by chitosan coated montmorillonite at lower temperature. The kinetics of the sorption process of chromium (VI on chitosan coated montmorillonite were investigated using the pseudo-first order and pseudo-second order kinetics, results showed that the pseudo-second order equation model provided the best correlation with the experimental results.

  15. A novel reusable nanocomposite: FeOOH/CBC and its adsorptive property for methyl orange

    Science.gov (United States)

    Wang, Zhuanpei; Ma, Yongjun; He, Honglei; Pei, Chonghua; He, Ping

    2015-03-01

    Porous network-like FeOOH/ carbonized bacterial cellulose (FeOOH/CBC) nanocomposite was successfully prepared and used as adsorbent of organic dyes. The phases, morphology, structure and adsorptive properties of FeOOH/CBC nanocomposite were characterized by XRD, FI-IR, SEM, TEM, BET and UV-vis. The adsorption equilibrium of as-prepared FeOOH/CBC nanocomposite for methyl orange (MO) was achieved within one hour, with the maximum adsorption capacity for MO reaching 107.68 mg/g at pH 6.0 and 30 °C. As-prepared FeOOH/CBC nanocomposite maintains high adsorption activities after four times of adsorption and desorption, accompanying the removal rate for MO is up to 60% in 10 min.

  16. Predicting the adsorption properties of carbon dioxide corrosion inhibitors using a structure-activity relationship

    Energy Technology Data Exchange (ETDEWEB)

    Kinsella, B.; De Marco, R.; Jefferson, A.; Pejcic, B. [Western Australian Corrosion Research Group, Department of Applied Chemistry, Curtin University of Technology, GPO Box U1987, Perth, 6845, WA (Australia); Durnie, W. [Nalco/Exxon Energy Chemicals Ltd, Hardley, Hythe, Southampton (Australia)

    2004-07-01

    This paper presents a study of the influence of various chemical inhibitors on the corrosion rate of mild steel in brine electrolyte under carbon dioxide conditions. The performances as corrosion inhibitors were fitted to a Temkin adsorption isotherm, and various constants of adsorption (i.e., adsorption equilibrium constants and molecular interaction constants) have been obtained. The inhibitor adsorption mechanism has been discussed in terms of thermodynamics (i.e., {delta}H, {delta}G and {delta}S) and this revealed that some compounds chemisorbed onto the steel electrode. In addition, molecular modelling was undertaken using PCSPARTAN Plus and HyperChem Professional, and the various molecular parameters have been correlated with the thermodynamic adsorption properties of the inhibitors. A four-parameter fit for both negative and positive charged molecules is discussed. (authors)

  17. The study of adsorption properties of magnetic spinels. 2. Influence of synthesis conditions on adsorption of heavy metal ions

    OpenAIRE

    GRIBANOVA ELENA VLADIMIROVNA; VASUTIN OLEG ALEKSEEVICH; LARIONOV MAXIM IGOREVICH; KUCHEK ANASTASIJA EDUARDOVNA

    2015-01-01

    Analysis of sorption properties of the fine spinel Mn0.7Zn0.3Fe2O4, obtained by co-precipitation method (“basic” sample) and also: at different temperatures; in different media (“40% ethanol”) and surface modification in the liquid phase (“PVA” and “Zn”), was performed by adsorption of Cu 2+ and Pb 2+ ions. The concentration of these ions was determined by atomic emission spectroscopy with inductively coupled plasma on Perkin Elmer Optima 7300 DV. The experiments have shown that the best adsorpti...

  18. Preparation of porous nano barium ferrite and its adsorption properties on uranium

    International Nuclear Information System (INIS)

    The porous nano barium ferrite was made of Fe(NO3)3 and Ba(NO3)2 as raw materials, CTAB as surfactant by method of sol-gel and self-propagating combustion. The composition, morphology and magnetic properties of nano-rod barium ferrite were characterized by XRD, SEM and vibrating sample magnetometer. The adsorption properties of porous nano barium ferrite on uranium were studied with static adsorption and the effects of pH, adsorption temperature and oscillation time on adsorption properties were discussed. The results indicate that the average particle size of porous nano barium ferrite is 45-65 nm, the saturation magnetization and coercivity are 62.83 emu/g and 5481.0 Oe, respectively. Under the condition of the porous nano barium ferrite amount of 0.02 g, pH of 6, adsorption temperature of 25℃ and oscillation time of 30 min, the adsorption capacity of uranium on the porous nano barium ferrite reaches 921 μg/g. (authors)

  19. Preparation of activated carbons and their adsorption properties for greenhouse gases: CH4 and CO2

    Institute of Scientific and Technical Information of China (English)

    Hao Yang; Maochu Gong; Yaoqiang Chen

    2011-01-01

    Three kinds of activated carbons were prepared using coconut-shells as carbon precursors and characterized by XRD,FT-IR and texture property test.The results indicate that the prepared activated carbons were mainly amorphous and only a few impurity groups were adsorbed on their surfaces.The texture property test reveals that the activated carbons displayed different texture properties,especially the micropore size distribution.The adsorption capacities of the activated carbons were investigated by adsorbing CH4,CO2,N2 and O2 at 25 ℃ in the pressure range of 0-200 kPa.The results reveal that all the activated carbons had high CO2 adsorption capacity,one of which had the highest CO2 adsorption value of 2.55 mmol/g at 200 kPa.And the highest adsorption capacity for CH4 of the activated carbons can reach 1.93 mmol/g at 200 kPa.In the pressure range of 0-200 kPa,the adsorption capacities for N2 and O2 were increased linearly with the change of pressure and K-AC is an excellent adsorbent towards the adsorption separation of greenhouse gases.

  20. Adsorption/desorption properties of vacuum materials for the 6 GeV synchrotron

    International Nuclear Information System (INIS)

    Considerable attention must be paid to the vacuum and adsorption/desorption properties of all materials installed inside the vacuum envelope if the design goals of the 6 GeV synchrotron are to be met. Unfortunately, the data is very sparse in several key areas. Additionally, some procedures normally associated with good vacuum practice, such as air baking, may prove to be totally unsuitable on the basis of desorption properties. We present here a brief discussion of the adsorption, outgassing, electron-stimulated desorption (ESD), and photon-stimulated desorption (PSD) properties of vacuum materials as they relate to the design of a 6 GeV synchrotron

  1. Structural properties and adsorption capacity of holocellulose aerogels synthesized from an alkali hydroxide-urea solution

    Energy Technology Data Exchange (ETDEWEB)

    Kwon, Gu-Joong; Kim, Dae-Young; Hwang, Jae-Hyun; Kang, Joo-Hyon [Dongguk University, Seoul (Korea, Republic of)

    2014-05-15

    A tulip tree was used to synthesize a holocellulose aerogel from an aqueous alkali hydroxide-urea solution with the substitution of an organic solvent followed by freeze-drying. For comparison, the synthesized holocellulose aerogels were divided into two groups according to the source of the hydrogel, an upper suspended layer and a bottom concentrated layer of the centrifuged solution of cellulose and NaOH/urea solvents. We investigated the effects of the temperature of the pre-cooled NaOH/urea solution (i.e., dissolution temperature) on the pore structure and the adsorption capacity of the holocellulose aerogel. A nano-fibrillar network structure of the holocellulose aerogel was observed, with little morphological difference in pore structure for different dissolution temperatures. Both micropores and mesopores were observed in the holocellulose aerogel. The specific surface area of the holocellulose aerogel was generally greater at lower dissolution temperatures. In a series of adsorption tests using methylene blue, the holocellulose aerogel showed the greatest adsorption capacity at the lowest dissolution temperature tested ( -2 .deg. C). However, the dissolution temperature generally had little effect on the adsorption capacity. The holocellulose aerogel produced from the upper suspended layer of the centrifuged hydrogel solution showed a greater porosity and adsorption capacity than the one produced from the bottom concentrated layer. Overall, the aerogel made by utilizing a delignified tulip tree display a high surface area and a high adsorption property, indicating its possible application in eco-friendly adsorption materials.

  2. Structural properties and adsorption capacity of holocellulose aerogels synthesized from an alkali hydroxide-urea solution

    International Nuclear Information System (INIS)

    A tulip tree was used to synthesize a holocellulose aerogel from an aqueous alkali hydroxide-urea solution with the substitution of an organic solvent followed by freeze-drying. For comparison, the synthesized holocellulose aerogels were divided into two groups according to the source of the hydrogel, an upper suspended layer and a bottom concentrated layer of the centrifuged solution of cellulose and NaOH/urea solvents. We investigated the effects of the temperature of the pre-cooled NaOH/urea solution (i.e., dissolution temperature) on the pore structure and the adsorption capacity of the holocellulose aerogel. A nano-fibrillar network structure of the holocellulose aerogel was observed, with little morphological difference in pore structure for different dissolution temperatures. Both micropores and mesopores were observed in the holocellulose aerogel. The specific surface area of the holocellulose aerogel was generally greater at lower dissolution temperatures. In a series of adsorption tests using methylene blue, the holocellulose aerogel showed the greatest adsorption capacity at the lowest dissolution temperature tested ( -2 .deg. C). However, the dissolution temperature generally had little effect on the adsorption capacity. The holocellulose aerogel produced from the upper suspended layer of the centrifuged hydrogel solution showed a greater porosity and adsorption capacity than the one produced from the bottom concentrated layer. Overall, the aerogel made by utilizing a delignified tulip tree display a high surface area and a high adsorption property, indicating its possible application in eco-friendly adsorption materials.

  3. Influence of Al substitution on magnetism and adsorption properties of hematite

    Energy Technology Data Exchange (ETDEWEB)

    Cao, Shanshan; Kang, Feifei; Yang, Xin; Zhen, Zhen [College of Chemistry and Material Science, Hebei Normal University, Shijiazhuang 050024 (China); Liu, Hui, E-mail: liuhuicn@126.com [College of Chemistry and Material Science, Hebei Normal University, Shijiazhuang 050024 (China); Key Laboratory of Inorganic Nanomaterial of Hebei Province, Shijiazhuang 050024 (China); Chen, Rufen [College of Chemistry and Material Science, Hebei Normal University, Shijiazhuang 050024 (China); Key Laboratory of Inorganic Nanomaterial of Hebei Province, Shijiazhuang 050024 (China); Wei, Yu, E-mail: weiyu@mail.hebtu.edu.cn [College of Chemistry and Material Science, Hebei Normal University, Shijiazhuang 050024 (China); Key Laboratory of Inorganic Nanomaterial of Hebei Province, Shijiazhuang 050024 (China)

    2015-08-15

    A series of Al-substituted hematite was prepared. The structures and properties of as-prepared samples were characterized by various techniques. The magnetic property of the samples was determined and the adsorption of three dyes Acid Blue 74, Methylene Blue and Phenol Red onto the samples was investigated. The results showed that Al incorporation into the crystal structure of hematite occurs via isomorphous ionic substitution of Al for Fe. With increasing Al content, the particle size of samples decreases, the magnetization increases and the remanent magnetization remains unchanged. The coercivity of the samples increases with Al substitution up to n{sub Al}/n{sub Fe} 0.03, and then decreases as Al content further increases. Compared with Al-free hematite, Al-substituted samples exhibit better adsorption ability to all of the three dyes. The adsorption rates of the three dyes on the surface of Al substituted samples depend on the structure of dye, pH and Al content in hematite. - Graphical abstract: Effect of Al on the structure, magnetic properties and adsorption performance of hematite was investigated. - Highlights: • A series of Al-substituted α-Fe{sub 2}O{sub 3} was prepared. • Effect of Al content on the crystal structure and magnetic property of hematite was investigated. • Al-substituted hematite exhibits better adsorption ability than hematite.

  4. Influence of Al substitution on magnetism and adsorption properties of hematite

    International Nuclear Information System (INIS)

    A series of Al-substituted hematite was prepared. The structures and properties of as-prepared samples were characterized by various techniques. The magnetic property of the samples was determined and the adsorption of three dyes Acid Blue 74, Methylene Blue and Phenol Red onto the samples was investigated. The results showed that Al incorporation into the crystal structure of hematite occurs via isomorphous ionic substitution of Al for Fe. With increasing Al content, the particle size of samples decreases, the magnetization increases and the remanent magnetization remains unchanged. The coercivity of the samples increases with Al substitution up to nAl/nFe 0.03, and then decreases as Al content further increases. Compared with Al-free hematite, Al-substituted samples exhibit better adsorption ability to all of the three dyes. The adsorption rates of the three dyes on the surface of Al substituted samples depend on the structure of dye, pH and Al content in hematite. - Graphical abstract: Effect of Al on the structure, magnetic properties and adsorption performance of hematite was investigated. - Highlights: • A series of Al-substituted α-Fe2O3 was prepared. • Effect of Al content on the crystal structure and magnetic property of hematite was investigated. • Al-substituted hematite exhibits better adsorption ability than hematite

  5. Surface modification, characterization and adsorptive properties of a coconut activated carbon

    Science.gov (United States)

    Lu, Xincheng; Jiang, Jianchun; Sun, Kang; Xie, Xinping; Hu, Yiming

    2012-08-01

    A coconut activated carbon was modified using chemical methods. Different concentration of nitric acid oxidation of the conventional sample produced samples with weakly acidic functional groups. The oxidized samples were characterized by scanning electron micrograph, nitrogen absorption-desorption, Fourier transform infra red spectroscopy, Bothem method, pH titration, adsorption capacity of sodium and formaldehyde, and the adsorption mechanism of activated carbons was investigated. The results showed that BET surface area and pore volume of activated carbons were decreased after oxidization process, while acidic functional groups were increased. The surface morphology of oxidized carbons looked clean and eroded which was caused by oxidization of nitric acid. The oxidized carbons showed high adsorption capacity of sodium and formaldehyde, and chemical properties of activated carbon played an important role in adsorption of metal ions and organic pollutants.

  6. Adsorption of Ti atoms on zigzag silicene nanoribbons: influence on electric, magnetic, and thermoelectric properties

    International Nuclear Information System (INIS)

    We study the adsorption effects of Ti atoms on the physical properties of zigzag silicene nanoribbons using the density functional theory combined with the nonequilibrium Green’s function methods. The adsorption geometries, conductance spectra, current voltage curves, spin polarizations, magnetoresistance, and Seebeck coefficients are evaluated in different adsorption samples. Ti adatoms prefer sites inside the nanoribbons instead of on the edges. Two neighboring adatoms are attractively coupled and prefer being adsorbed on the same side. The giant magnetoresistance in nanoribbons of even width is usually greatly reduced, except in symmetric adsorption cases. Strong spin negative differential resistance phenomena can be observed and pure spin current can be produced by temperature gradient in specific cases. (paper)

  7. Surface modification, characterization and adsorptive properties of a coconut activated carbon

    International Nuclear Information System (INIS)

    A coconut activated carbon was modified using chemical methods. Different concentration of nitric acid oxidation of the conventional sample produced samples with weakly acidic functional groups. The oxidized samples were characterized by scanning electron micrograph, nitrogen absorption-desorption, Fourier transform infra red spectroscopy, Bothem method, pH titration, adsorption capacity of sodium and formaldehyde, and the adsorption mechanism of activated carbons was investigated. The results showed that BET surface area and pore volume of activated carbons were decreased after oxidization process, while acidic functional groups were increased. The surface morphology of oxidized carbons looked clean and eroded which was caused by oxidization of nitric acid. The oxidized carbons showed high adsorption capacity of sodium and formaldehyde, and chemical properties of activated carbon played an important role in adsorption of metal ions and organic pollutants.

  8. Adsorption properties of the components of the InSb-CdTe system

    International Nuclear Information System (INIS)

    Piezoquartz microweighing was used to study the adsorption of nitrogen dioxide on films prepared from solid solutions and the binary compounds of the InSb-CdTe system. An analysis of experimental dependences, thermodynamic and kinetic characteristics of adsorption, electrophysical, acid-base, and other physicochemical properties of the adsorbents (with consideration given to the electronic structure of the adsorbate molecule), as well as adsorption characteristic-composition diagrams, made it possible to establish the mechanism and regularities of adsorption processes for various experimental conditions and compositions of the system. Some aspects of the behavior of multicomponent solid solutions and the constituent binary compounds (InSb and CdTe) were found to be similar while the others different

  9. Adsorption-desorption properties and characterization of crosslinked Konjac glucomannan-graft-polyacrylamide-co-sodium xanthate.

    Science.gov (United States)

    Wang, Lu-Feng; Duan, Jia-Cai; Miao, Wen-Hua; Zhang, Ruo-Jie; Pan, Si-Yi; Xu, Xiao-Yun

    2011-02-28

    A new flocculant, based on Konjac-graft-poly (acrylamide)-co-sodium xanthate (CKAX), was synthesized in aqueous solution using epichlorohydrin (ECH) as the cross-linker and ceric ammonium nitrate (CAN) as the initiator. X-ray diffraction indicated the existence of strong interaction between KGM and reactant, including intermolecular and intramolecular hydrogen bonds. Microscopy images exhibited the appropriate pore size and distribution, which might be related to a higher capacity of flocculation and adsorption. Thermo gravimetric analysis showed that the synthetic polymer could improve the thermo-stability of the natural polysaccharides, and there was a positive correlation between polymer residual weight and flocculation. The adsorption and desorption properties for copper ions indicated that the adsorption rate could be described by a pseudo-second-order rate model, and the Freundlich model provides the best fit for the resulting adsorption isotherm. The flocculant can be regenerated in HNO(3) solution. PMID:21236570

  10. Adsorption-desorption properties and characterization of crosslinked Konjac glucomannan-graft-polyacrylamide-co-sodium xanthate

    International Nuclear Information System (INIS)

    A new flocculant, based on Konjac-graft-poly (acrylamide)-co-sodium xanthate (CKAX), was synthesized in aqueous solution using epichlorohydrin (ECH) as the cross-linker and ceric ammonium nitrate (CAN) as the initiator. X-ray diffraction indicated the existence of strong interaction between KGM and reactant, including intermolecular and intramolecular hydrogen bonds. Microscopy images exhibited the appropriate pore size and distribution, which might be related to a higher capacity of flocculation and adsorption. Thermo gravimetric analysis showed that the synthetic polymer could improve the thermo-stability of the natural polysaccharides, and there was a positive correlation between polymer residual weight and flocculation. The adsorption and desorption properties for copper ions indicated that the adsorption rate could be described by a pseudo-second-order rate model, and the Freundlich model provides the best fit for the resulting adsorption isotherm. The flocculant can be regenerated in HNO3 solution.

  11. Adsorption-desorption properties and characterization of crosslinked Konjac glucomannan-graft-polyacrylamide-co-sodium xanthate

    Energy Technology Data Exchange (ETDEWEB)

    Wang Lufeng; Duan Jiacai; Miao Wenhua; Zhang Ruojie; Pan Siyi [College of Food Science and Technology, Huazhong Agricultural University, No.1, Shizishan Street, Wuhan, Hubei 430070 (China); Xu Xiaoyun, E-mail: xiaoyunxu88@gmail.com [College of Food Science and Technology, Huazhong Agricultural University, No.1, Shizishan Street, Wuhan, Hubei 430070 (China)

    2011-02-28

    A new flocculant, based on Konjac-graft-poly (acrylamide)-co-sodium xanthate (CKAX), was synthesized in aqueous solution using epichlorohydrin (ECH) as the cross-linker and ceric ammonium nitrate (CAN) as the initiator. X-ray diffraction indicated the existence of strong interaction between KGM and reactant, including intermolecular and intramolecular hydrogen bonds. Microscopy images exhibited the appropriate pore size and distribution, which might be related to a higher capacity of flocculation and adsorption. Thermo gravimetric analysis showed that the synthetic polymer could improve the thermo-stability of the natural polysaccharides, and there was a positive correlation between polymer residual weight and flocculation. The adsorption and desorption properties for copper ions indicated that the adsorption rate could be described by a pseudo-second-order rate model, and the Freundlich model provides the best fit for the resulting adsorption isotherm. The flocculant can be regenerated in HNO{sub 3} solution.

  12. Adsorption properties of aluminium oxide modified with palladium, gold, and cerium oxide nanoparticles

    Science.gov (United States)

    Lanin, S. N.; Bannykh, A. A.; Vinogradov, A. E.; Kovaleva, N. V.; Lanina, K. S.; Nikolaev, S. A.

    2016-07-01

    The adsorption properties of nanocomposites based on γ-Al2O3 modified with CeO x , Au/CeO x , and Pd/CeO x nanoparticles with contents of deposited metals ranging from 0.07 to 1.71 wt % are investigated by means of dynamic sorption method. n-Alkanes (C6-C8), acetonitrile, diethyl ether, tetrahydrofuran, and dioxane are used as test adsorbates. Adsorption isotherms are measured, and the isosteric heats of adsorption of a number of test adsorbates are calculated. Electron-donor and electron-acceptor characteristics of the surfaces of γ-Al2O3-based nanocomposites are estimated. It is shown that Au(0.1%)/CeO x (0.07%)/γ-Al2O3 nanocomposite, which has the lowest content of nanoparticles of the deposited metals, has the highest adsorption activity.

  13. Sensitizing mechanism and adsorption properties of dye-sensitized TiO sub 2 thin films

    CERN Document Server

    Hu Zhi Xue; Wang Kong Jia

    2002-01-01

    The dye-sensitized TiO sub 2 complex films were prepared by the dye coat onto TiO sub 2 surfaces, and the sensitizing mechanism and adsorption properties of the dye-sensitized TiO sub 2 complex films were investigated. The influence of the application conditions of dye adsorbed on TiO sub 2 films on the amount of dye adsorption was discussed. Experimental results show that the concentration, the temperature of dye solutions and the dipping time of TiO sub 2 films in the dye solutions have a significant influence on the amount of dye adsorption. Cell test indicates that the conversion efficiency of light to electricity increases with the amount of dye adsorption

  14. Study of tin oxide: Surface properties and palladium adsorption

    Science.gov (United States)

    Katsiev, Khabiboulakh

    Surface properties of various single-crystalline SnO2 surfaces were studied and the growth of palladium was investigated in the low-coverage regime. Metal - oxide structures play an important role in microelectronics and nanotechnology. They are also widely used in catalysis. Small catalytically-active metal particles on metal oxide substrates are key features in the gas sensing mechanism: they dramatically increase the sensitivity and selectivity of solid-state gas sensors towards target gases. Tin Oxide is widely used in solid-state gas sensors for detection of combustible and toxic gases. Its sensitivity and selectivity strongly depends on catalytic dopants, such as Pd or Pt, on the surface of the material. Thus, the characterization of Pd growth on tin oxide may give new insights into the catalytic and gas sensing mechanisms, and also help to understand fundamental steps that lead to various metal-on-oxide growth modes. Upon deposition of Pd onto the reduced (101) surface of a SnO2 single crystal, 1D cluster growth was observed. Starting from very low coverages, one-dimensional Pd clusters grow on the terraces, which indicates that the Pd wets the reduced tin oxide surface. Pd deposition on the oxidized surface results in randomly distributed three-dimensional Pd clusters. The clusters are distributed at step edges and on terraces without any apparent preferential adsorption sites. The one-dimensional clusters are imaged in scanning tunneling microscopy (STM) as straight, parallel nanostructures oriented along the [-101] direction, all with the same characteristic width of 0.5 nm and a height of 1 monolayer (ML). X-ray photoelectron spectroscopy (XPS) experiments show no sign of Pd oxidation; i.e. Pd grows as a metal. There is a 0.5 eV shift in the Pd 3d 5/2 core level peak position to lower binding energy that occurs during the initial stages of the growth on the reduced surface. This is an indication of charge transfer from the Pd clusters to the substrate

  15. Effects of Peptide Adsorption on the Electronic Properties of Graphene

    Science.gov (United States)

    Akdim, Brahim; Kuang, Zhifeng; Kim, Sang; Naik, Rajesh; Farmer, Barry; Walsh, Tiffany; Pachter, Ruth

    2012-02-01

    In this work we aim to explain the increase in the electrical conductance in a single-layer graphene (SLG) field-effect transistor (FET) upon binding the peptide HSSYWYAFNNKT, which we previously demonstrated. The adsorption of the peptide onto the SLG has been carefully modeled by applying empirical molecular dynamics simulations with the AMOEBA force-field. The peptide adsorbed SLG structure demonstrates π-π stacking with aromatic amino acids, namely His,Tyr, Thr and Ph. Based on this large-scale peptide-SLG system, calculations on the electron transport using the nonequilibrium Green's function formalism at the extended Huckel level were carried out. Transmission eigenchannels and spectra, projected density of states, effects of modeling realistic leads (gold vs. graphene) and I-V characteristics will be discussed in detail. In this context, suppositions as to the mechanism of increased conductance for the peptide-SLG FET will be proposed.

  16. Modifying the catalytic and adsorption properties of metals and oxides

    Science.gov (United States)

    Yagodovskii, V. D.

    2015-11-01

    A new approach to interpreting the effect of promoters (inhibitors) of nonmetals and metals added to a host metal (catalyst) is considered. Theoretical calculations are based on a model of an actual two-dimensional electron gas and adsorbate particles. An equation is derived for the isotherm of induced adsorption on metals and semiconductors with respect to small fillings of θ ~ 0.1-0.15. The applicability of this equation is verified experimentally for metals (Ag, Pd, Cu, Fe, and Ni), graphitized ash, and semiconductor oxides Ta2O5, ZnO, and Ni. The applicability of the theoretical model of promotion is verified by the hydrogenation reaction of CO on ultradispersed nickel powder. The use of plasmachemical surface treatments of metals and oxides, accompanied by an increase in activity and variation in selectivity, are investigated based on the dehydrocyclization reactions of n-hexane and the dehydrogenation and dehydration of alcohols. It is established that such treatments for metals (Pt, Cu, Ni, and Co) raise their activity due to the growth of the number of active centers upon an increase in the activation energy. Applying XPES and XRD methods to metallic catalysts, it is shown that the rise in activity is associated with a change in their surface states (variation in the structural characteristics of metal particles and localization of certain forms of carbon in catalytically active centers). It is shown that plasmachemical treatments also alter their surface composition, surface activity, and raise their activity when used with complex phosphate oxides of the NASICON type. It is shown by the example of conversion of butanol-2 that abrupt variations in selectivity (prevalence of dehydration over dehydrogenation and vice versa) occur, depending on the type of plasma. It is concluded that plasmachemical treatments of metals and ZnO and NiO alter the isosteric heats and entropies of adsorption of isopropanol.

  17. Adsorption property of citrate dispersant on BaTiO3 particles in aqueous solution

    Institute of Scientific and Technical Information of China (English)

    SU Tao-long; ZHUANG Zhi-qiang

    2007-01-01

    Dispersion behavior of ultra fine BaTiO3 particles in the aqueous solution of ammonium citrate (NH4-CA) or citric acid lanthanum chelate (NH4-La-CA) was investigated. The dispersion property was characterized with sedimentation value. It is easier to obtain well dispersed slurry with NH4La-CA than NH4-CA. In an attempt to better understand the role of citric acid radical,simulation of the dispersant adsorption on BaTiO3 particle was performed with universal force field (UFF). It is demonstrated that the interaction between citric acid radical and BaTiO3 particle surface is a weak chemical adsorption. Trivalent citric acid radical is adsorbed on BaTiO3 particle surface with maximal adsorption energy. And, larger molecules of NH4-La-CA formed by adding La3+ lead to better dispersion property than NH4-CA.

  18. Adsorptive property of Cu2+-loaded montmorillonite clays for Escherichia coli K88 in vitro

    Institute of Scientific and Technical Information of China (English)

    Tong Guo; Shoujun Cao; Rui Su; Zhiqiang Li; Ping Hu; Zirong Xu

    2011-01-01

    The adsorption properties of Cu2+-loaded montmorillonite clays (MMT-Cu) for Escherichia coli K88 as a function of time,bacteria concentrations,pH,ionic strength and temperature were investigated.The results showed that the bacteria adsorption onto MMT-Cu surface reached equilibrium after 90 min.The percentages of E.coli K88 adsorbed onto the surfaces of MMT-Cu and montmorillonite clays (MMT) at equilibrium were 88.9% and 56.5%,respectively.Scanning electron microscopy revealed that a lot of E.coli K88 adhered to the surface of MMT-Cu.The zeta potential of MMT-Cu was relatively high as compared to that of MMT.The adsorptive ability of MMT-Cu for E.coli K88 was higher than that of MMT (P < 0.05).Moreover,pH,ionic strength and temperature produced a strong influence on the extent of E.coli K88 adsorption to surface of MMT-Cu and MMT.The mechanism of adsorption of E.coli onto MMT-Cu may involve electrostatic attraction and physiochemical properties of bacterial cell walls and minerals surfaces.

  19. Adsorption properties of boroxol ring doped zigzag boron nitride nanotube toward NO molecule using DFT

    Science.gov (United States)

    Zahedi, Ehsan; Babaie, Mahsa; Bahmanpour, Hooman

    2016-05-01

    In previous researches it is demonstrated that reactivity and sensitivity of boron nitride nanotubes (BNNTs) toward gas molecules can be modified by impurity. In this work, oxygen defect for three nitrogen sites was used to study the adsorption of NO molecule through the surface of boroxol ring of oxygen doped BNNT (7,0) with different adsorption patterns, including side-on and end-on. All calculations are performed using the DFT-B3LYP/6-31G∗ level of theory, and their electronic energies are corrected by gCP and D3 correction terms. High binding energies indicate that NO molecule undergoes chemical adsorption with large charge transfer from the tube which can significantly change electronic properties of the tube. Density of state (DOS) and partial DOS (PDOS) analyses revealed that adsorption of NO molecule on the boroxol ring position is covalent in nature with significant effect on the electronic properties of tube. The Laplacian of electron density, Lagrangian kinetic energy density, Hamiltonian kinetic energy density and potential energy density at bond critical points between the tube and NO indicate that the interaction between the tube and NO molecule is covalent in nature. Topological analysis of the electron localization function shows that electrons in the new formed bonds are approximately localized, meaning that the nature of adsorption process is chemical covalent. The studied nanotube is a suitable candidate to filter and eliminate NO gas molecule.

  20. Equilibrium geometric structure and electronic properties of Cl and H2O co-adsorption on Fe (100) surface

    Institute of Scientific and Technical Information of China (English)

    ZHAO Wei; WANG JiaDao; LIU FengBin; CHEN DaRong

    2009-01-01

    Based on the first principles density functional theory,the equilibrium geometric structure and surface electronic properties of Cl and H2O co-adsorption on the Fe (100) surface are investigated.The results indicate that the optimal adsorption site for Cl and H2O co-adsorption on the Fe (100) surface is the location of Cl at the bridge site and H2O at the top site.Compared with the Fe (100)/H2O adsorption system,remarkable changes in geometric structure and electronic properties occur,owing to the presence of Cl in the Fe (100)/(H2O+Cl) adsorption system.The analysis of equilibrium geometric structure and surface electronic properties shows that the presence of Cl in the Fe (100)/(H2O+Cl) ad-sorption system unstablizes the Fe surface,making it easy to lose electrons.

  1. BCN: a graphene analogue with remarkable adsorptive properties.

    Science.gov (United States)

    Raidongia, Kalyan; Nag, Angshuman; Hembram, K P S S; Waghmare, Umesh V; Datta, Ranjan; Rao, C N R

    2010-01-01

    A new analogue of graphene containing boron, carbon and nitrogen (BCN) has been obtained by the reaction of high-surface-area activated charcoal with a mixture of boric acid and urea at 900 degrees C. X-ray photoelectron spectroscopy and electron energy-loss spectroscopy reveal the composition to be close to BCN. The X-ray diffraction pattern, high-resolution electron microscopy images and Raman spectrum indicate the presence of graphite-type layers with low sheet-to-sheet registry. Atomic force microscopy reveals the sample to consist of two to three layers of BCN, as in a few-layer graphene. BCN exhibits more electrical resistivity than graphene, but weaker magnetic features. BCN exhibits a surface area of 2911 m(2) g(-1), which is the highest value known for a B(x)C(y)N(z) composition. It exhibits high propensity for adsorbing CO(2) ( approximately 100 wt %) at 195 K and a hydrogen uptake of 2.6 wt % at 77 K. A first-principles pseudopotential-based DFT study shows the stable structure to consist of BN(3) and NB(3) motifs. The calculations also suggest the strongest CO(2) adsorption to occur with a binding energy of 3.7 kJ mol(-1) compared with 2.0 kJ mol(-1) on graphene. PMID:19946909

  2. STUDY ON THE THERMODYNAMIC PROPERTIES OF ADSORPTION OF ETHYL BENZOATE AND DIETHYL PHTHALATE BY PHENOLIC RESIN ADSORBENTS

    Institute of Scientific and Technical Information of China (English)

    Zhong Wang; Zuo-qing Shi; Rong-fu Shi; Yun-ge Fan; Yi-zhong Yang

    2004-01-01

    This paper presents experimental observations on the adsorption of individual solutes by a simple thermodynamic framework, and the equilibrium adsorption of ethyl benzoate and diethyl phthalate on phenolic resin adsorbent in hexane solutions within the temperature range of 293-313 K. The experimental results show that the Freundlich adsorption law is applicable to the adsorption of ethyl benzoate and diethyl phthalate on the adsorbent, since all the correlative factors R' are larger than 0.99. The negative values of all the isosteric adsorption enthalpies for ethyl benzoate and diethyl phthalate indicate that they undergo exothermic processes, while their magnitudes (19-28 kJ/mol) manifest a hydrogen bonding sorption process. Other thermodynamic properties: the free energy changes and the entropy change associated with the adsorption have been calculated from the Gibbs adsorption equation and the Gibbs-Helmholtz equation.

  3. Cr-Doped ZnO Nanoparticles: Synthesis, Characterization, Adsorption Property, and Recyclability.

    Science.gov (United States)

    Meng, Alan; Xing, Jing; Li, Zhenjiang; Li, Qingdang

    2015-12-16

    In this paper, a mild solvothermal method has been employed to successfully synthesize a series of Cr-doped ZnO nanoparticles (NPs) with different Cr(3+) contents, which is a kind of novel and high-efficiency absorbent for the removal of acid dye methyl orange (MO) from aqueous solution. The as-prepared products were characterized by transmission electron microscopy (TEM), scanning electron microscopy (SEM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), Fourier transform infrared spectroscopy (FT-IR), Brunauer, Emmet, and Teller (BET), and Zeta potential measurements. In accordance with the adsorption capacity of the products, the obtained optimal Cr/Zn molar ratio is 6%. The adsorption process of MO on Cr-doped ZnO was investigated by kinetics, thermodynamics, and isotherm technologies, which, respectively, indicated that the adsorption was fast (adsorption reached equilibrium in 2 h) and followed a pseudo-second-order model, that the adsorption process was spontaneous and endothermic, and that it agreed well with the Langmuir isotherm with a maximum adsorption capacity of 310.56 mg g(-1). Moreover, a reasonable mechanism was proposed to elucidate the reasons for their adsorption behavior. In addition, a simple and low-cost chemical method was developed to separate and recycle ZnO and MO from the used adsorbent, effectively avoiding the secondary pollution. This work can not only describe efficient experimental approaches for obtaining novel adsorbents and recycling them but also offer valuable clues for the preparation and property study of other semiconductor adsorbents. PMID:26600320

  4. The adsorption properties of the ZnSe-CdSe system components

    International Nuclear Information System (INIS)

    Adsorption properties of solid solutions ZnxCd1-xSe and their binary components (ZnSe and CdSe) in reference to ammonia and carbon dioxide were studied by the method of thermodesorption spectroscopy with manometric and mass-spectrometric analysis of desorption products, IR and ESR spectroscopy. The adsorbents mentioned were powders with specific surface 0.91-1.40 m2/g and monocrystals. It was ascertained that ammonia, which is a probe for acid centers on the surface, is adsorbed better by 1-2 orders than carbon dioxide. It permitted making conclusion on the nature of active centers in the selenides studied and on adsorption mechanism. Regularities in the change of adsorption activity of components in the system ZnSe-CdSe were established

  5. Physical and lithium-adsorptive properties of manganese oxide adsorbent granulated with polyvinyl chloride (PVC)

    International Nuclear Information System (INIS)

    The granulation of powdered manganese-oxide adsorbent was carried out with PVC as a binder. A strength test on the basis of shaking method showed that the breakage of the granulated adsorbent was less than 1% when the PVC content was above 20%. The lithium adsorptive properties of the granulated adsorbent was investigated by both a batch and column methods. It showed a high selectivity for lithium in sea water. The added PVC had a slight influence on the lithium adsorptivity. The lithium uptake by the adsorbent (particle diameter, 2.0-2.8 mm) reached 4.5 mg·g-1 after the column operation for 50 days at 15-22 degC. The granule had a sufficient stability after the adsorption experiment. (author)

  6. The influence of the degree of cross-linking on the adsorption properties of chitosan beads.

    Science.gov (United States)

    Osifo, Peter O; Webster, Athena; van der Merwe, Hein; Neomagus, Hein W J P; van der Gun, Marius A; Grant, David M

    2008-10-01

    The influence of the degree of cross-linking (DCL) on chitosan beads was studied. Chitosan was prepared from the exoskeleton of Cape rock-lobsters, collected from the surroundings of Cape Town, South Africa. The chitosan beads were characterized; the beads water contents and pKa varied in the range of 90-96% and 4.3-6.0, respectively, and were found to decrease with increasing DCL (0.0-34.0%). A pH-model, which described the reversibility of the metal adsorbed onto the beads, was used to predict the equilibrium properties of copper adsorption onto the cross-linked beads. The model accounts for the effect of pH and the important model parameters, the equilibrium adsorption constant (Kads) and to a lesser extent the adsorbent adsorption capacity (qmax) showed to decrease with the DCL. The adsorbent capacity and the adsorption constant were determined as 3.8-5.0mmol/g chitosan and (9-90)x10(-4), respectively. The adsorption kinetics could be described using a shrinking core model and the effective diffusion coefficient (Deff) was determined as (8.0-25.8)x10(-11)m2/s. It was found that Deff decreases with the DCL mainly due to the decreased in water content of the beads at high DCL. PMID:18342504

  7. The surface modification of stainless steel and the correlation between the surface properties and protein adsorption.

    Science.gov (United States)

    Kang, Chan-Koo; Lee, Yoon-Sik

    2007-07-01

    Protein adsorption on a biomaterial surface is of great importance as it usually induces unfavorable biological cascades, with the result that much surface modification research has had to be performed in an effort to prevent this. In this study, we developed surface modification methods for stainless steel, which is a representative metal for biomedical device. The stainless steels were first smoothened to different extents by electropolishing, in order to obtain a rough or smooth surface. On these two kinds of substrates, we introduced epoxide groups to the metal surface by silanization with 3-glycidoxypropyltrimethoxysilane (GPTS). Then, various polymers such as poly(ethylene glycol) (PEG), poly(tetrahydrofuran glycol) (PTG), poly(propylene glycol) (PPG) and poly(dimethylsiloxane) (PDMS) were grafted on the silanized stainless steels. Each surface modification step was confirmed by various analytical methods. Contact angle measurement revealed that the surface hydrophilicity was controllable by polymer grafting. Root-mean-square (RMS) data of atomic force microscopy showed that surface roughness was dramatically changed by electropolishing. Based on these results, the correlation between surface properties and protein adsorption was investigated. In the protein adsorption study, we observed that all of the polymer-grafted stainless steels exhibited lower protein adsorption, when compared with bare stainless steel. Moreover, a hydrophilic and smooth surface was found to be the best of choice for decreasing the protein adsorption. PMID:17277988

  8. A pulse chromatographic study of the adsorption properties of the amino-MIL-53 (Al) metal-organic framework.

    Science.gov (United States)

    Couck, Sarah; Rémy, Tom; Baron, Gino V; Gascon, Jorge; Kapteijn, Freek; Denayer, Joeri F M

    2010-08-28

    Low-coverage adsorption properties of the metal-organic framework amino-MIL-53 (Al) were determined using the pulse chromatographic technique. By using n-alkanes, iso-alkanes, 1-alkenes, cyclohexane and benzene as probe molecules, the nature of the adsorptive interactions in amino-MIL-53 (Al) was studied. Henry adsorption constants and adsorption enthalpies of iso-alkanes are significantly lower than those of the linear alkanes, demonstrating the shape selective properties of amino-MIL-53. The presence of amino-groups in the pores of the material increases the electrostatic contributions with molecules containing double bonds. A simple model relates adsorption enthalpies to the number of hydrogen atoms and double bonds in the molecule. The effective pore size of the material was estimated based on the relationship between adsorption enthalpy and entropy. PMID:20532387

  9. Effect of liquid cow manure on andisol properties and atrazine adsorption.

    Science.gov (United States)

    Briceño, Gabriela; Demanet, Rolando; de la Luz Mora, María; Palma, Graciela

    2008-01-01

    Application of animal manure amendments to agricultural soils is a common practice to improve soil fertility through the addition of essential plant nutrients. This practice may increase the potential for atrazine (2-chloro-4-ethylamino-6-isopropylamino-1, 3, 5-triazine) leaching due to competition for adsorption sites between the pesticide and dissolved organic carbon (DOC) added through manure. We evaluated the influence of liquid cow manure (LCM) application on soil properties, atrazine adsorption, and the physicochemical controlling mechanisms in an Andisol. The LCM was applied at rates equivalent to 0, 100,000, 200,000, and 300,000 L ha(-1), resulting in treatments S-0, S-100, S-200, and S-300, respectively. The LCM application increased DOC and pH of the soils immediately on addition, but pH returned to S-0 values 30 d after application. The LCM application did not modify atrazine adsorption with the two lowest application rates (S-100 and S-200), but atrazine adsorption was decreased in S-300 (K(f) = 0.96) compared with the control (S-0) (K(f) = 1.19), possibly due to the competitive adsorption of DOC with the pesticide. The Fourier-transformed infrared analysis showed that LCM increased aliphaticity and presence of N-containing groups and polysaccharide-like groups in amended soils; however, these properties did not modify the atrazine interaction in the studied amended soils. Interestingly the addition of DOC to soil at the high application rate (S-300) reduced atrazine adsorption in this rich OM Andisol despite the LCM not raising the concentration of stable organic matter. The application of high rates of liquid manure containing DOC incurs an increased risk of pesticide leaching. PMID:18574184

  10. Characterization of sorption properties of selected soils from Lublin region by using water vapour adsorption method

    Science.gov (United States)

    Skic, Kamil; Boguta, Patrycja; Sokołowska, Zofia

    2016-04-01

    *The studies were carried out within the framework of a research project. The project was financed from funds of National Science Center on the base of decision number DEC-2013/11/D/NZ9/02545 Among many methods proposed to study sorption properties of soils an analysis of adsorption/ desorption isotherm is probably the easiest and most convenient one. It characterizes both quantity and quality of mineral and organic components and also their physical and physicochemical properties. The main aim of this study is comparison of sorption properties of selected Polish soils by using water vapour adsorption method. Samples were taken from the depth of 0-20 cm, from the Lublin region, eastern Poland. Soils were selected on the basis of their different physicochemical properties and were classified as: Haplic Fluvisol, Haplic Chernozem, Mollic Gleysol, Rendzic Phaeozem, Stagnic Luvisol, Haplic Cambisol (WG WRB 2006). Data taken from experimental adsorption isotherms were used to determine parameters of monolayer capacity, specific surface area and the total amount of vapour adsorbed at relative pressure of 0.974. Obtained adsorption and desorption isotherms reviled that adsorbate molecules interacted with the soil particles in different extent. Similar monolayer capacity was observed for Haplic Fluvisol, Haplic Chernozem and Stagnic Luvisol, while for Mollic Gleysol was more than 4 times higher. Mollic Gleysol was also characterized by highest values of specific surface area as well as quantity of adsorbed vapour at relative pressure of 0.974. Higher sorption was caused by presence of soil colloids which contains functional groups of a polar nature (mainly hydroxyls, phenolic and carboxyls). These groups similarly to silicates, oxides, hydratable cations as well as electric charge form adsorption centres for water vapour molecules.

  11. Adsorption, Separation, and Catalytic Properties of Densified Metal-Organic Frameworks

    Energy Technology Data Exchange (ETDEWEB)

    Nandasiri, Manjula I.; Jambovane, Sachin R.; McGrail, B. Peter; Schaef, Herbert T.; Nune, Satish K.

    2016-03-15

    Metal-organic frameworks (MOFs) are one of the widely investigated materials of 21st century due to their unique properties such as structural tailorability, controlled porosity and crystallinity. These exceptional properties make them promising candidates for various applications including gas adsorption and storage, separation, and catalysis. However, commercial applications of MOFs produced by conventional methods including solvothermal or hydrothermal synthesis are rather limited or restricted because they often produce fine powders. The use of MOF powders for industrial applications often results in pressure drop problems similar to the case with Zeolites. To realize these materials for practical applications, densification of MOFs is routinely employed to form pellets, extrudates or beads to improve the overall density, volumetric adsorption, mechanical and thermal properties. However, the improvements come with some drawbacks such as reduction in overall porosity, surface area, and gravimetric adsorption capacity. Thus, optimizing the properties of densified MOF’s by tuning the packing density is very crucial for realizing these materials for industrial applications. In this review, various methods of densification of MOFs, their properties, and applications are discussed.

  12. Investigation of the surface adsorption and biotribological properties of mucins

    DEFF Research Database (Denmark)

    Madsen, Jan Busk

    Tribology is the study of friction, wear, adhesion and lubrication. Biotribology covers all aspects of tribology that are related to biological systems. Most organisms face tribological challenges where increased friction is often desirable, such as walking, gripping and lifting objects or adhering...... physical barrier that reduces adhesion to, and penetration of, the epithelial cell layer by bacteria. The composition of the mucin macromolecules includes hydrophobic globular terminal domains that are separated by heavily glycosylated (hydrophilic) central domains. The central domains carry an overall...... mucins and their aqueous lubrication properties have led to them being proposed as possible biocompatible lubricants. In this thesis, we investigate the biotribological properties of two commercially available mucins on the soft, elastomeric and hydrophobic surface of PDMS under different conditions. Due...

  13. Influence of the pore structure and surface chemical properties of activated carbon on the adsorption of mercury from aqueous solutions

    International Nuclear Information System (INIS)

    Highlights: • Activated carbons with different pore structure and surface chemical properties were prepared by modification process. • HgCl2 as a pollution target to evaluate the adsorption performance. • Influence of pore structure and surface chemical properties of activated carbon on adsorption of mercury was investigated. -- Abstract: Reactivation and chemical modification were used to obtain modified activated carbons with different pore structure and surface chemical properties. The samples were characterized by nitrogen absorption–desorption, Fourier transform infrared spectroscopy and the Bothem method. Using mercury chloride as the target pollutant, the Hg2+ adsorption ability of samples was investigated. The results show that the Hg2+ adsorption capacity of samples increased significantly with increases in micropores and acidic functional groups and that the adsorption process was exothermic. Different models and thermodynamic parameters were evaluated to establish the mechanisms. It was concluded that the adsorption occurred through a monolayer mechanism by a two-speed process involving both rapid adsorption and slow adsorption. The adsorption rate was determined by chemical reaction

  14. Aqueous phase adsorption of different sized molecules on activated carbon fibers: Effect of textural properties.

    Science.gov (United States)

    Prajapati, Yogendra N; Bhaduri, Bhaskar; Joshi, Harish C; Srivastava, Anurag; Verma, Nishith

    2016-07-01

    The effect that the textural properties of rayon-based activated carbon fibers (ACFs), such as the BET surface area and pore size distribution (PSD), have on the adsorption of differently sized molecules, namely, brilliant yellow (BY), methyl orange (MO) and phenol (PH), was investigated in the aqueous phase. ACF samples with different BET areas and PSDs were produced by steam-activating carbonized fibers for different activation times (0.25, 0.5, and 1 h). The samples activated for 0.25 h were predominantly microporous, whereas those activated for relatively longer times contained hierarchical micro-mesopores. The adsorption capacities of the ACFs for the adsorbate increased with increasing BET surface area and pore volume, and ranged from 51 to 1306 mg/g depending on the textural properties of the ACFs and adsorbate size. The adsorption capacities of the hierarchical ACF samples followed the order BY > MO > PH. Interestingly, the number of molecules adsorbed by the ACFs followed the reverse order: PH > MO > BY. This anomaly was attributed to the increasing molecular weight of the PH, MO and BY molecules. The equilibrium adsorption data were described using the Langmuir isotherm. This study shows that suitable textural modifications to ACFs are required for the efficient aqueous phase removal of an adsorbate. PMID:27107386

  15. Thermoemission and adsorption properties of diborides of transition metals of IV-V groups in cesium vapours

    International Nuclear Information System (INIS)

    Emission and adsorption properties of titanium, zirconium, hafnium, vanadium diborides were studied in vacuum and cesium vapours. Some regularities were established in changes of thermoemission properties in transition from one boride to another. Under pressures p0K interaction of these diborides with cesium plasma is of adsorption character. Evaluation of absorption properties for the diborides in cesium vapours showed for oprimal surface coating with cesium the adsorption energy for cesium ions is qsub(a)=(1.1/1.3) eV and work function is phi sub(min)=(1.25/1.45) eV

  16. Liquid-phase adsorption of multi-ring thiophenic sulfur compounds on carbon materials with different surface properties.

    Science.gov (United States)

    Zhou, Anning; Ma, Xiaoliang; Song, Chunshan

    2006-03-16

    This work examines the effects of structural and surface properties of carbon materials on the adsorption of benzothiophene (BT), dibenzothiophene (DBT), 4-methyldibenzothiophene (4-MDBT) and 4,6-dimethyl-dibenzothiophene (4,6-DMDBT) in the presence of 10 wt % of aromatics in liquid alkanes that simulate sulfur compounds in diesel fuels. The equilibrium-adsorption capacity varies significantly, from 1.7 to 7.0 mg-S/g-A. The results show that different carbon materials have significantly different sulfur-adsorption capacities and selectivities that depend not only on textural structure but also on surface functional groups. The adsorption of multi-ring sulfur compounds on carbon materials was found to obey the Langmuir isotherm. On the basis of adsorption tests and the characterization of carbon materials by BET and XPS, the oxygen-containing functional groups on the surface appear to play an important role in increasing sulfur-adsorption capacity. The adsorption-selectivity trend of the carbon materials for various compounds increases in the order of BT adsorption over nickel-based adsorbents. The regeneration of spent activated carbons was also conducted by solvent washing. The high-adsorption capacity and selectivity for methyl DBTs indicate that certain activated carbons are promising adsorbents for selective adsorption for removing sulfur (SARS) as a new approach to ultra deep desulfurization of diesel fuels. PMID:16526705

  17. Thermoemission and adsorption properties of tungsten alloy with osmium in cesium atoms flow

    International Nuclear Information System (INIS)

    Thermoemission and absorption properties of (110) and (100) planes of monocrystal of W+0.5%Os melt in a flux of cesium atoms are studied. Despite the fact that the electron work function from planes (100) and (110) was only 0.05 eV different it turned out during adsorption of Cs atoms that plane (110) adsorbes cesium atoms much better and reduces the work function to a greater extent

  18. Polydisperse Adsorption: Pattern Formation Kinetics, Fractal Properties, and Transition to Order

    OpenAIRE

    Brilliantov, N. V.; Andrienko, Yu. A.; Krapivsky, P. L.; Kurths, J.

    1998-01-01

    We investigate the process of random sequential adsorption of polydisperse particles whose size distribution exhibits a power-law dependence in the small size limit, $P(R)\\sim R^{\\alpha-1}$. We reveal a relation between pattern formation kinetics and structural properties of arising patterns. We propose a mean-field theory which provides a fair description for sufficiently small $\\alpha$. When $\\alpha \\to \\infty$, highly ordered structures locally identical to the Apollonian packing are forme...

  19. Insights into Materials Properties from Ab Initio Theory : Diffusion, Adsorption, Catalysis & Structure

    OpenAIRE

    Blomqvist, Andreas

    2010-01-01

    In this thesis, density functional theory (DFT) calculations and DFT based ab initio molecular dynamics simulations have been employed in order to gain insights into materials properties like diffusion, adsorption, catalysis, and structure. In transition metals, absorbed hydrogen atoms self-trap due to localization of metal d-electrons. The self-trapping state is shown to highly influence hydrogen diffusion in the classical over-barrier jump temperature region. Li diffusion in Li-N-H systems ...

  20. Comparative study of carbon nanotubes and granular activated carbon: Physicochemical properties and adsorption capacities.

    Science.gov (United States)

    Gangupomu, Roja Haritha; Sattler, Melanie L; Ramirez, David

    2016-01-25

    The overall goal was to determine an optimum pre-treatment condition for carbon nanotubes (CNTs) to facilitate air pollutant adsorption. Various combinations of heat and chemical pre-treatment were explored, and toluene was tested as an example hazardous air pollutant adsorbate. Specific objectives were (1) to characterize raw and pre-treated single-wall (SW) and multi-wall (MW) CNTs and compare their physical/chemical properties to commercially available granular activated carbon (GAC), (2) to determine the adsorption capacities for toluene onto pre-treated CNTs vs. GAC. CNTs were purified via heat-treatment at 400 °C in steam, followed by nitric acid treatment (3N, 5N, 11N, 16N) for 3-12 h to create openings to facilitate adsorption onto interior CNT sites. For SWNT, Raman spectroscopy showed that acid treatment removed impurities up to a point, but amorphous carbon reformed with 10h-6N acid treatment. Surface area of SWNTs with 3 h-3N acid treatment (1347 m(2)/g) was higher than the raw sample (1136 m(2)/g), and their toluene maximum adsorption capacity was comparable to GAC. When bed effluent reached 10% of inlet concentration (breakthrough indicating time for bed cleaning), SWNTs had adsorbed 240 mg/g of toluene, compared to 150 mg/g for GAC. Physical/chemical analyses showed no substantial difference for pre-treated vs. raw MWNTs. PMID:26476807

  1. Dye adsorption and bactericidal properties of TiO2/chitosan coating layer.

    Science.gov (United States)

    Kamal, Tahseen; Anwar, Yasir; Khan, Sher Bahadar; Chani, Muhammad Tariq Saeed; Asiri, Abdullah M

    2016-09-01

    A new kind of titanium oxide dispersed in chitosan (TiO2/CS) nanocomposite adsorbent was prepared and adhered to high surface area substrate, cellulose microfibers mat (CMM). CS-CMM and TiO2/CS-CMM were used for the thymol violet (TV) dye removal from wastewater. Characterization of materials was carried out by X-ray diffraction, scanning electron microscope and energy dispersive X-ray spectroscopy. The adsorption properties of both the CS-CMM and TiO2/CS-CMM were investigated as a function of adsorbent dosage, solution pH, and contact time. It was revealed that the composites pretreated in the solution with higher pH value exhibited larger adsorption capacities. Kinetic studies showed that the composites could adsorb TV dye rapidly and reached the equilibrium in 90min. The adsorption process followed pseudo-second order kinetics and involved particle diffusion mechanism. The calculated maximum adsorption capacities of CS-CMM and TiO2/CS-CMM were 84.32 and 97.51mgg(-1), respectively. Compare to CS, the TiO2/CS nanocomposite coated CMM showed higher antibacterial characteristics as tested against Escherichia coli. PMID:27185126

  2. Predicting adsorption of aromatic compounds by carbon nanotubes based on quantitative structure property relationship principles

    Science.gov (United States)

    Rahimi-Nasrabadi, Mehdi; Akhoondi, Reza; Pourmortazavi, Seied Mahdi; Ahmadi, Farhad

    2015-11-01

    Quantitative structure property relationship (QSPR) models were developed to predict the adsorption of aromatic compounds by carbon nanotubes (CNTs). Five descriptors chosen by combining self-organizing map and stepwise multiple linear regression (MLR) techniques were used to connect the structure of the studied chemicals with their adsorption descriptor (K∞) using linear and nonlinear modeling techniques. Correlation coefficient (R2) of 0.99 and root-mean square error (RMSE) of 0.29 for multilayered perceptron neural network (MLP-NN) model are signs of the superiority of the developed nonlinear model over MLR model with R2 of 0.93 and RMSE of 0.36. The results of cross-validation test showed the reliability of MLP-NN to predict the K∞ values for the aromatic contaminants. Molar volume and hydrogen bond accepting ability were found to be the factors much influencing the adsorption of the compounds. The developed QSPR, as a neural network based model, could be used to predict the adsorption of organic compounds by CNTs.

  3. Adsorptive Properties of Dyes to Cellulosic Sheet and Discoloration of Dye Solution by UV-ray Irradiation

    Institute of Scientific and Technical Information of China (English)

    Zhou Yu; Iida Ikuho; Minato Kazuya; Kurosu Hiroshi

    2005-01-01

    The adsorptive properties and selectivity of dyes and water molecules to cellulosic sheet, dependence of adsorptive properties of dyes on the concentration of dye solution, and discoloration of the dye solution due to the UV-ray irradiation were determined for 18 kinds of commercial dyes. The results are as follows: 1) the adsorptive properties of dyes to cellulose sheet differed greatly, but did not depend on the dye types such as acidic, basic and so on; 2) adsorptive properties of dyes to cellulosic sheet depended on the concentration of dye solution and were classified into 4 types: concentration-independent, increasing or decreasing with dye concentration, and having a maximum. This classification was irrelevant to the dye types; 3) the irradiation of UV-ray did not cause significant discoloration of dye solution itself, which suggested that wood components as well as dye molecules influence the discoloration of wood.

  4. Relationship between adsorption of arsenic(III) and boron by soil and soil properties

    Energy Technology Data Exchange (ETDEWEB)

    Sakata, M.

    1987-11-01

    The distribution coefficients (K/sub d/) for arsenic(III) and boron in a linear adsorption isotherm were determined for 15 subsurface soils collected from different sites in Japan, and the relationship between those K/sub d/ values and soil properties was examined. The soils differed greatly in their chemical and physical properties. The K/sub d/ value for arsenic(III) was significantly correlated with the dithionite-extractable Fe content in the soils (r = 0.90), whereas a high positive correlation was also found between the K/sub d/ value for boron and the oxalate-extractable Al content in the soils (r = 0.98). These relationships imply that the adsorption of arsenic(III) and boron by soil is controlled mainly by levels of amorphous iron oxides and hydroxides for arsenic(III) and by levels of allophane for boron and are very useful for assessing the adsorption of arsenic(III) and boron released in the underlying soil layer at coal ash disposal sites. 22 references, 6 figures, 3 tables.

  5. Adsorption properties of CoPc molecule on epitaxial graphene/Ru(0 0 0 1)

    Energy Technology Data Exchange (ETDEWEB)

    Cai, Yiliang; Zhang, Hanjie; Song, Junjie; Zhang, Yuxi; Bao, Shining; He, Pimo, E-mail: phypmhe@zju.edu.cn

    2015-02-01

    Graphical abstract: - Highlights: • The adsorption behavior of CoPc on MG/Ru(0 0 0 1) was investigated by STM and DFT. • The impact of the defect in MG/Ru(0 0 0 1) on the adsorption properties was studied. • A central contrast was found for CoPcs adsorbed on intact and defective graphene. - Abstract: Combining the scanning tunneling microscopy (STM) and density functional theory (DFT), the adsorption properties of cobalt phthalocyanine (CoPc) on monolayer graphene/Ru(0 0 0 1) [MG/Ru(0 0 0 1)] have been investigated. At monolayer coverage, CoPc forms an ordered Kagome lattice, and a slight deformation for one lobe of CoPc and charge transfer from CoPc to Ru(0 0 0 1) substrate take place. The existence of the defect (vacancy) in graphene on Ru(0 0 0 1) increases the coupling between the Ru substrate and the epitaxial graphene. Such an increase of the coupling brings about an overall CoPc molecular energy level shift toward the low binding energy, which subsequently results in a central topographical contrast between the CoPc molecules on the intact and defective MG/Ru(0 0 0 1)

  6. Synthesis of Hydrophobic Mesoporous Material MFS and Its Adsorption Properties of Water Vapor

    Directory of Open Access Journals (Sweden)

    Guotao Zhao

    2014-01-01

    Full Text Available Fluorine-containing hydrophobic mesoporous material (MFS with high surface area is successfully synthesized with hydrothermal synthesis method by using a perfluorinated surfactant SURFLON S-386 template. The adsorption properties of water vapor on the synthesized MFS are also investigated by using gravimetric method. Results show that SEM image of the MFS depicted roundish morphology with the average crystal size of 1-2 μm. The BET surface area and total pore volume of the MFS are 865.4 m2 g−1 and 0.74 cm3 g−1 with a narrow pore size distribution at 4.9 nm. The amount of water vapor on the MFS is about 0.41 mmol g−1 at 303 K, which is only 52.6% and 55.4% of MCM-41 and SBA-15 under the similar conditions, separately. The isosteric adsorption heat of water on the MFS is gradually about 27.0–19.8 kJ mol−1, which decreases as the absorbed water vapor amount increases. The value is much smaller than that on MCM-41 and SBA-15. Therefore, the MFS shows more hydrophobic surface properties than the MCM-41 and SBA-15. It may be a kind of good candidate for adsorption of large molecule and catalyst carrier with high moisture resistance.

  7. Fast Prediction of Adsorption Properties for Platinum Nanocatalysts with Generalized Coordination Numbers

    DEFF Research Database (Denmark)

    Calle-Vallejo, Federico; Martinez, Jose I.; García Lastra, Juan Maria;

    2014-01-01

    Platinum is a prominent catalyst for a multiplicity of reactions because of its high activity and stability. As Pt nanoparticles are normally used to maximize catalyst utilization and to minimize catalyst loading, it is important to rationalize and predict catalytic activity trends in nanoparticles...... the generalized coordination numbers of the surface sites. This simple and predictive descriptor links the geometric arrangement of a surface to its adsorption properties. It generates linear adsorption-energy trends, captures finite-size effects, and provides more accurate descriptions than d......-band centers and usual coordination numbers. Unlike electronic-structure descriptors, which require knowledge of the densities of states, it is calculated manually. Finally, it was shown that an approximate equivalence exists between generalized coordination numbers and d-band centers....

  8. Porosity and adsorption properties of activated carbon derived from palm oil waste

    International Nuclear Information System (INIS)

    Activated carbon have extensively been used as adsorbents in industry for the removal of pollutant species from gases for the purpose of purification and recovery of chemicals. The adsorption properties of the carbons depend very much on the porosity and type of pore presents which can be generated and controlled during synthesis and activation steps. This paper reports the effect of chemical activation by ZnCl3, KOH and nh4OH on the porosity of carbon produced from palm oil industry waste. Type of pores will further be validated by the SEM micrograph. The amount of gas adsorbed, the adsorption capacities can also be estimated based on the BET experiments data. The applicability of the produced carbon materials for the removal and exchange of hazardous incinerator gas is discussed. (Author)

  9. Effect of Water Vapor Adsorption on Electrical Properties of Carbon Nanotube/Nanocrystalline Cellulose Composites.

    Science.gov (United States)

    Safari, Salman; van de Ven, Theo G M

    2016-04-13

    It has been long known that the electrical properties of cellulose are greatly influenced by adsorption of water vapor. Incorporating conductive nanofillers in a cellulose matrix is an example of an approach to tailor their characteristics for use in electronics and sensing devices. In this work, we introduce two new nanocomposites comprising carbon nanotubes (CNTs) and conventional or electrosterically stabilized nanocrystalline celluloses matrices. While conventional nanocrystalline cellulose (NCC) consists of a rigid crystalline backbone, electrosterically stabilized cellulose (ENCC) is composed of a rigid crystalline backbone with carboxylated polymers protruding from both ends. By tuning CNT loading, we can tailor a CNT/NCC composite with minimal electrical sensitivity to the ambient relative humidity, despite the fact that the composite has a high moisture uptake. The expected decrease in CNT conductivity upon water vapor adsorption, due to electron donation, is counterbalanced by an increase in the conductivity of NCC due to proton hopping at an optimum CNT loading (1-2%). Contrary to the CNT/NCC composite, a CNT/ENCC composite at 1% CNT loading shows insulating behavior for relative humidities up to 75%, after which the composite becomes conductive. This interesting behavior can be ascribed to the low moisture uptake of ENCC at low and moderate relative humidities due to the limited number of hydroxyl groups and hydrogen bond formation between carboxyl groups on ENCC, which endow ENCC with limited water molecule adsorption sites. PMID:26998641

  10. Adsorption and Flame Retardant Properties of Bio-Based Phytic Acid on Wool Fabric

    Directory of Open Access Journals (Sweden)

    Xian-Wei Cheng

    2016-04-01

    Full Text Available Bio-based phytic acid (PA as a nontoxic naturally occurring compound is a promising prospect for flame-retardant (FR modifications to polymers. In this work, PA was applied to wool fabric using an exhaustion technique, and the adsorption and FR properties of PA on wool fabric were studied. The flame retardancy of the treated wool fabrics depended greatly on the adsorption quantity of PA, which was related to the pH of treatment solution, immersing temperature and initial PA concentration. The Langmuir adsorption of PA took place due to electrostatic interactions between PA and wool fiber. The limiting oxygen index, vertical burning and pyrolysis combustion flow calorimetry tests revealed that the treated wool fabrics exhibited good flame retardancy. The measurements of the phosphorus content of the burned fabric residues and thermogravimetric analyses suggested that a significant condensed-phase FR action was applicable to the PA treated fabrics. PA treatment was found to have little adverse effect on the whiteness and mechanical performance of wool. Additionally, the washing resistance of the FR fabrics should be further improved.

  11. Adsorption and aqueous lubricating properties of charged and neutral amphiphilic diblock copolymers at a compliant, hydrophobic interface.

    Science.gov (United States)

    Røn, Troels; Javakhishvili, Irakli; Jankova, Katja; Hvilsted, Søren; Lee, Seunghwan

    2013-06-25

    We have investigated the adsorption and lubricating properties of neutral and charged amphiphilic diblock copolymers at a hydrophobic polydimethylsiloxane (PDMS) interface in an aqueous environment. The diblock copolymers consist of a hydrophilic block of either neutral poly(ethylene glycol) (PEG) or negatively charged poly(acrylic acid) (PAA) and of a hydrophobic block of polystyrene (PS) or poly(2-methoxyethyl acrylate) (PMEA), thus generating PEG-b-X or PAA-b-X, where X block is either PS or PMEA. The molecular weight ratios were roughly 1:1 with each block ca. 5 kDa. Comparing the neutral PEG and charged PAA buoyant blocks with all other conditions identical, the former showed superior adsorption onto nonpolar, hydrophobic PDMS surfaces from a neutral aqueous solution. PEG-based copolymers showed substantial adsorption for both PS and PMEA as the anchoring block, whereas PAA-based copolymers showed effective adsorption only when PMEA was employed as the anchoring block. For PAA-b-PS, the poor adsorption properties are chiefly attributed to micellization due to the high interfacial tension between the PS core and water. The poor lubricating properties of PAA-b-PS diblock copolymer for a PDMS-PDMS sliding contact was well correlated with the poor adsorption properties. PAA-b-PMEA copolymers, despite their sizable amount of adsorbed mass, showed insignificant lubricating effects. When the charges of the PAA-b-PMEA diblock copolymers were screened by either adding NaCl to the aqueous solution or by lowering the pH, both the adsorption and lubricity improved. We ascribe the poor adsorption and inferior aqueous lubricating properties of the PAA-based diblock copolymers compared to their PEG-based counterparts mainly to the electrostatic repulsion between charged PAA blocks, hindering the facile formation of the lubricating layer under cyclic tribological stress at the sliding PDMS-PDMS interface. PMID:23725290

  12. Carbon key-properties for microcystin adsorption in drinking water treatment: structure or surface chemistry?

    OpenAIRE

    Júlio, Maria de Fátima de Jesus Leal

    2011-01-01

    The carbon key-properties (structure and surface chemistry) for microcystin-LR (MC-LR) adsorption onto activated carbon were investigated. Waters with an inorganic background matrix approaching that of the soft natural water (2.5 mM ionic strength) were used. Also, model waters with controlled ionic make-up and NOM surrogate with similar size of MC-LR (tannic acid - TA) with MC-LR extracts were tested with activated carbon NORIT 0.8 SUPRA. For this AC, two particle sizes, 125-180 μm and 63-90...

  13. Clarification of the oxygen adsorption properties of YBaCo_4O_7 at high temperature by thermogravimetry

    Institute of Scientific and Technical Information of China (English)

    朱保峰; 郝好山; 张勇; 贾建峰; 胡行

    2010-01-01

    The oxygen adsorption/desorption properties of YBaCo4O7 at high temperature were investigated by thermogravimetry(TG) method,in which two types of oxygen adsorption were combined.The first type adsorbed oxygen at about 700 °C and released the adsorbed oxygen at 880 °C.After the first type oxygen desorption,even the temperature and oxygen flow were kept the same,a second type oxygen adsorption at about 880 °C occurred and the adsorbed oxygen were released at above 980 °C.The combination of these two types of...

  14. Adsorption and Aqueous Lubricating Properties of Charged and Neutral Amphiphilic Diblock Copolymers at a Compliant, Hydrophobic Interface

    DEFF Research Database (Denmark)

    Røn, Troels; Javakhishvili, Irakli; Jankova Atanasova, Katja;

    2013-01-01

    PEG and charged PAA buoyant blocks with all other conditions identical, the former showed superior adsorption onto nonpolar, hydrophobic PDMS surfaces from a neutral aqueous solution. PEGbased copolymers showed substantial adsorption for both PS and PMEA as the anchoring block, whereas PAA......-based copolymers showed effective adsorption only when PMEA was employed as the anchoring block. For PAA-b-PS, the poor adsorption properties are chiefly attributed to micellization due to the high interfacial tension between the PS core and water. The poor lubricating properties of PAA-b-PS diblock copolymer for......, hindering the facile formation of the lubricating layer under cyclic tribological stress at the sliding PDMS−PDMS interface. © American Chemical Society...

  15. The effects of crystallographic surface inhomogeneity on double-layer structure and adsorption properties of cadmium electrodes

    International Nuclear Information System (INIS)

    At Cd electrodes, electric double-layer structure was studied in solutions of surface-inactive electrolytes, while the adsorption properties were studied in solutions containing surface-active organic cations. Splitting of the adsorption-desorption peak of tetrabutylammonium ions was found at a polished polycrystalline Cd electrode. The splitting was not seen in solutions containing tetrapropyl- or tetraethylammonium ions, nor at a cadmium surface renewed by cutting inside the solution

  16. Influence of Epicuticular Physicochemical Properties on Porcine Rotavirus Adsorption to 24 Leafy Green Vegetables and Tomatoes.

    Directory of Open Access Journals (Sweden)

    Lu Lu

    Full Text Available Foodborne diseases are a persistent problem in the United States and worldwide. Fresh produce, especially those used as raw foods like salad vegetables, can be contaminated, causing illness. In this study, we determined the number of rotaviruses adsorbed on produce surfaces using group A porcine rotaviruses and 24 cultivars of leafy vegetables and tomato fruits. We also characterized the physicochemical properties of each produce's outermost surface layer, known as the epicuticle. The number of rotaviruses found on produce surfaces varied among cultivars. Three-dimensional crystalline wax structures on the epicuticular surfaces were found to significantly contribute to the inhibition of viral adsorption to the produce surfaces (p = 0.01. We found significant negative correlations between the number of rotaviruses adsorbed on the epicuticular surfaces and the concentrations of alkanes, fatty acids, and total waxes on the epicuticular surfaces. Partial least square model fitting results suggest that alkanes, ketones, fatty acids, alcohols, contact angle and surface roughness together can explain 60% of the variation in viral adsorption. The results suggest that various fresh produce surface properties need to be collectively considered for efficient sanitation treatments. Up to 10.8% of the originally applied rotaviruses were found on the produce surfaces after three washing treatments, suggesting a potential public health concern regarding rotavirus contamination.

  17. Characterizing adsorptive properties and DOC concentrations in soils of Northern European Russian tundra and taiga.

    Science.gov (United States)

    Oosterwoud, Marieke; Temminghoff, Erwin; van der Zee, Sjoerd

    2010-05-01

    Subarctic river basins have an enormous potential to mobilize and transport terrestrial OC to the Arctic Ocean, because 23-48% of the worlds soils organic carbon (SOC) is stored in the high latitude region. Currently the Arctic drainage basin (~24 x 106 km2) processes about 11% of the global dissolved organic carbon (DOC), which is exported to the ocean. About 10-25% of annual C input to the organic surface layer with litter is leached from the organic surface layers. As climate changes, the amount and chemical composition of DOC exported from these basins are expected to change. Adsorption of DOC on mineral phases is the key geochemical process for the release and removal of DOC from this potentially soluble carbon pool. Most DOC leached from organic horizons is adsorbed and retained in the subsoils. The adsorption depends much on the content of sesquioxides and amount of carbon previously accumulated in soils. Besides adsorption, polyvalent metal ions in solution, such as Al and Ca, can cause precipitation of DOC. Along with the decrease of DOC concentrations on its passage through mineral soil, there are major biochemical alterations of DOC composition. Hydrophobic compounds (humic and fulvic acids) of high molecular weight that are rich in acidic functional groups and aromatic compounds adsorb most strongly. Hydrophilic compounds can contribute to DOC adsorption but are also easily desorbed because of the weaker bonding strength. The aim of this study was to characterize the DOC concentrations and their chemical composition as well as the DOC adsorptive properties of soils found in a tundra and taiga catchment of Northern Russia. We sampled soil and soil solution from two catchments in the Komi Republic of European Northern Russia: a tundra (67N/62E) and a taiga (62N/50E). The soil samples were analysed for total organic carbon (Ct) and the content of sequioxides. By extracting soil samples with water we got an impression of the potentially extractable organic

  18. To what extent can mutual shifting of folded carbonaceous walls in slit-like pores affect their adsorption properties?

    International Nuclear Information System (INIS)

    We have performed systematic Monte Carlo studies on the influence of shifting the walls in slit-like systems constructed from folded graphene sheets on their adsorption properties. Specifically, we have analysed the effect on the mechanism of argon adsorption (T  =  87 K) and on adsorption and separation of three binary gas mixtures: CO2/N2, CO2/CH4 and CH4/N2 (T  =  298 K). The effects of the changes in interlayer distance were also determined. We show that folding of the walls significantly improves the adsorption and separation properties in comparison to ideal slit-like systems. Moreover, we demonstrate that mutual shift of sheets (for small interlayer distances) causes the appearance of small pores between opposite bulges. This causes an increase in vapour adsorption at low pressures. Due to overlapping of interactions with opposite walls causing an increase in adsorption energy, the mutual shift of sheets is also connected with the rise in efficiency of mixture separation. The effects connected with sheet orientation vanish as the interlayer distance increases. (paper)

  19. Production of granular activated carbon from agricultural wastes and determination of their physical, chemical and adsorption properties

    Energy Technology Data Exchange (ETDEWEB)

    Ayguen, A.; Duman, I. [Istanbul Technical Univ., Inst. of Science and Technology, Dept. of Metallurgical Engineering, Istanbul (Turkey); Yenisoy-Karakas, S. [TUeBITAK Marmara Research Center (MRC), Materials and Chemical Technologies Research Inst., Gebze Kocaeli (Turkey)

    2004-07-01

    The aim of this study is to produce activated carbons with good mechanical strength and high adsorption capacities toward various organics from food wastes such as walnut, almond, hazelnut shells and apricot stones. Turkey has huge amounts of these wastes in canning industry. The chemical activation with ZnCl{sub 2} was preferred to manufacture activated carbons. The best activation temperature and time were determined. Granular activated carbons were discussed with respect to their physical, chemical, surface area and adsorption properties. For all raw materials, the specific surface areas of greater than 730 m{sup 2} g{sup -1} were reached. As a result of the adsorption studies, adsorption capacities were in order of hazelnut> apricot stones> walnut> almond. The correlation coefficients obtained from Langmuir and Freundlich isotherms are in good agreement with the experimental results. (orig.)

  20. Biocompatible Eu-doped TiO{sub 2} nanodot film with in situ protein adsorption characterization property

    Energy Technology Data Exchange (ETDEWEB)

    Cheng, Kui; Zhu, Yifei [Department of Materials Science and Engineering, State Key Laboratory of Silicon Materials, Cyrus Tang Center for Sensor Materials and Applications, Zhejiang University, Hangzhou 310027 (China); Weng, Wenjian, E-mail: wengwj@zju.edu.cn [Department of Materials Science and Engineering, State Key Laboratory of Silicon Materials, Cyrus Tang Center for Sensor Materials and Applications, Zhejiang University, Hangzhou 310027 (China); The Shanghai Institute of Ceramics, Chinese Academy of Sciences, 1295 Dingxi Road, Shanghai, 200050 (China); Lin, Jun; Wang, Huiming [The First Affiliated Hospital of Medical College, Zhejiang University, Hangzhou, 310003 (China)

    2015-06-01

    Europium (Eu) doped TiO{sub 2} nanodot films were prepared through a phase-separation-induced self-assembly method. Eu was doped to impart the nanodots with luminescence property so that the protein adsorption could be in situ characterized quantitatively. Bovine serum albumin (BSA) was adsorbed on the surface of Eu-doped titanium nanodot films. It was found that the photo luminescence intensity at 616 nm decreased with the increase of BSA adsorption time. Also, Eu-doped TiO{sub 2} nanodot films showed good biocompatibility. These results suggested that Eu-doped TiO{sub 2} nanodot films could provide a feasible in situ way to evaluate protein adsorption if prepared on the surface of bioimplants. - Highlights: • Simple preparation of Eu doped TiO{sub 2} nanodot films • Eu doped nanodot films show good biocompatibility. • Easy in situ evaluation of protein adsorption via photo luminescence of Eu.

  1. Biocompatible Eu-doped TiO2 nanodot film with in situ protein adsorption characterization property

    International Nuclear Information System (INIS)

    Europium (Eu) doped TiO2 nanodot films were prepared through a phase-separation-induced self-assembly method. Eu was doped to impart the nanodots with luminescence property so that the protein adsorption could be in situ characterized quantitatively. Bovine serum albumin (BSA) was adsorbed on the surface of Eu-doped titanium nanodot films. It was found that the photo luminescence intensity at 616 nm decreased with the increase of BSA adsorption time. Also, Eu-doped TiO2 nanodot films showed good biocompatibility. These results suggested that Eu-doped TiO2 nanodot films could provide a feasible in situ way to evaluate protein adsorption if prepared on the surface of bioimplants. - Highlights: • Simple preparation of Eu doped TiO2 nanodot films • Eu doped nanodot films show good biocompatibility. • Easy in situ evaluation of protein adsorption via photo luminescence of Eu

  2. Polydopamine-mediated surface functionalization of electrospun nanofibrous membranes: Preparation, characterization and their adsorption properties towards heavy metal ions

    International Nuclear Information System (INIS)

    Graphical abstract: - Highlights: • A simple and versatile approach to produce PEI-functionalized nanofibers. • Novel PEI-functionalized PVC nanofibrous membrane was prepared. • Adsorption of PVC@PDA and PVC@PDA-PEI nanofibrous membranes for Cu2+ was tested. • Isotherms, kinetic model and thermodynamic parameters were investigated. • Adsorption mechanism of Cu2+ on modified membranes was inferred. - Abstract: In this paper, a simple and versatile approach for the fabrication of a polyethyleneimine (PEI)-functionalized nanofibrous membrane utilizing polydopamine (PDA) as a mediator is proposed. The morphology and structure of the PDA-coated and PEI-grafted nanofibrous membranes were confirmed using scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS) and attenuated total reflectance Fourier transform infrared (ATR-FTIR) spectroscopy. Due to a large specific surface area and long fibrous morphology, the synthesized membranes were used as novel adsorbents for copper ion (Cu2+) removal from aqueous solutions. The adsorption of Cu2+ was investigated on the synthesized membranes regarding the membrane dosages, initial solution pH values, initial solution concentrations, contact times and temperatures. In addition, the adsorption equilibrium data of PEI-grafted membranes were well fitted with the Langmuir adsorption isotherm, and a maximum adsorption capacity value of 33.59 mg g−1 was determined (while it was 21.94 mg g−1 for the PDA-coated membranes). The thermodynamic parameters indicated that Cu2+ absorption was a spontaneous and exothermic adsorption process. In addition, XPS peak differentiation imitating analysis permitted the proposal of a copper-amine coordination adsorption mechanism that can be used to explain changes in the adsorption properties compared to PDA coating nanofibrous membranes

  3. Polydopamine-mediated surface functionalization of electrospun nanofibrous membranes: Preparation, characterization and their adsorption properties towards heavy metal ions

    Energy Technology Data Exchange (ETDEWEB)

    Wu, Chunlin [School of Chemistry and Chemical Engineering, Shihezi University, Shihezi 832003 (China); Wang, Heyun [School of Chemistry and Chemical Engineering, Shihezi University, Shihezi 832003 (China); Key Laboratory for Green Processing of Chemical Engineering of Xinjiang bingtuan, Shihezi University, Shihezi 832003 (China); Wei, Zhong, E-mail: steven_weiz@sina.com [School of Chemistry and Chemical Engineering, Shihezi University, Shihezi 832003 (China); Key Laboratory for Green Processing of Chemical Engineering of Xinjiang bingtuan, Shihezi University, Shihezi 832003 (China); Li, Chuan; Luo, Zhidong [School of Chemistry and Chemical Engineering, Shihezi University, Shihezi 832003 (China)

    2015-08-15

    Graphical abstract: - Highlights: • A simple and versatile approach to produce PEI-functionalized nanofibers. • Novel PEI-functionalized PVC nanofibrous membrane was prepared. • Adsorption of PVC@PDA and PVC@PDA-PEI nanofibrous membranes for Cu{sup 2+} was tested. • Isotherms, kinetic model and thermodynamic parameters were investigated. • Adsorption mechanism of Cu{sup 2+} on modified membranes was inferred. - Abstract: In this paper, a simple and versatile approach for the fabrication of a polyethyleneimine (PEI)-functionalized nanofibrous membrane utilizing polydopamine (PDA) as a mediator is proposed. The morphology and structure of the PDA-coated and PEI-grafted nanofibrous membranes were confirmed using scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS) and attenuated total reflectance Fourier transform infrared (ATR-FTIR) spectroscopy. Due to a large specific surface area and long fibrous morphology, the synthesized membranes were used as novel adsorbents for copper ion (Cu{sup 2+}) removal from aqueous solutions. The adsorption of Cu{sup 2+} was investigated on the synthesized membranes regarding the membrane dosages, initial solution pH values, initial solution concentrations, contact times and temperatures. In addition, the adsorption equilibrium data of PEI-grafted membranes were well fitted with the Langmuir adsorption isotherm, and a maximum adsorption capacity value of 33.59 mg g{sup −1} was determined (while it was 21.94 mg g{sup −1} for the PDA-coated membranes). The thermodynamic parameters indicated that Cu{sup 2+} absorption was a spontaneous and exothermic adsorption process. In addition, XPS peak differentiation imitating analysis permitted the proposal of a copper-amine coordination adsorption mechanism that can be used to explain changes in the adsorption properties compared to PDA coating nanofibrous membranes.

  4. Study on hydrogen atom adsorption and diffusion properties on Mg (0001) surface

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    Hydrogen atom adsorption and diffusion properties on clean and vacancy defective Mg (0001) surface have been investigated systematically by using a first-principles calculations method based on the density functional theory. The calculation results of adsorption energy and diffusion energy barrier show that hydrogen atom is apt to be adsorbed at fcc and hcp sites on clean Mg (0001) surface, and fcc adsorption site is found to be more preferred. The highest diffusion energy barrier is estimated as 0.6784 eV for the diffusion of hydrogen from clean Mg (0001) surface into its bulk. Surface effects, which affect hydrogen diffusion obviously, results in a slow diffusion velocity of hydrogen from surface to subsurface, while a fast one from subsurface to bulk, indicating the range of surface effects is only restricted within two topmost layers of Mg (0001) surface. Comparatively, Mg atom vacancy on Mg (0001) surface not only enhances the chemisorption interaction between H and Mg surface, but also benefits H atom diffusion in Mg bulk with relatively more diffusion paths compared with that of clean surface. Besides, hydrogen atom is found to occupy mostly the tetrahedral interstice when it diffuses into the Mg bulk. Further analysis of the density of states (DOS) shows that the system for hydrogen atom to be adsorbed at fcc site has a lower DOS value (N (EF)) at Fermi level and more bonding elec- trons at the energy range blow the Fermi level of H/Mg (0001) system as compared with that at hcp site. On the other hand, the enhanced chemisorption interaction between hydrogen and defective surface should be attributed to the fact that the electronic structures of Mg (0001) surface are modified by an Mg vacancy, and the bonding electrons of the topmost layer Mg atoms are transferred from low energy range to Fermi level, which is in favor of improving the surface activity of Mg (0001) surface.

  5. Study on hydrogen atom adsorption and diffusion properties on Mg (0001) surface

    Institute of Scientific and Technical Information of China (English)

    ZHANG dian; ZHOU DianWu; LIU dinShui

    2009-01-01

    Hydrogen atom adsorption and diffusion properties on clean and vacancy defective Mg (0001) surface have been investigated systematically by using a first-principles calculations method based on the density functional theory. The calculation results of adsorption energy and diffusion energy barrier show that hydrogen atom is apt to be adsorbed at fcc and hcp sites on clean Mg (0001) surface, and fcc adsorption site is found to be more preferred. The highest diffusion energy barrier is estimated as 0.6784 eV for the diffusion of hydrogen from clean Mg (0001) surface into its bulk. Surface effects,which affect hydrogen diffusion obviously, results in a slow diffusion velocity of hydrogen from surface to subsurface, while a fast one from subsurface to bulk, indicating the range of surface effects is only restricted within two topmost layers of Mg (0001) surface. Comparatively, Mg atom vacancy on Mg(0001) surface not only enhances the chemisorption interaction between H and Mg surface, but also benefits H atom diffusion in Mg bulk with relatively more diffusion paths compared with that of clean surface. Besides, hydrogen atom is found to occupy mostly the tetrahedral interstice when it diffuses into the Mg bulk. Further analysis of the density of states (DOS) shows that the system for hydrogen atom to be adsorbed at fcc site has a lower DOS value (N (EF)) at Fermi level and more bonding electrons at the energy range blow the Fermi level of H/Mg (0001) system as compared with that at hcp site.On the other hand, the enhanced chemisorption interaction between hydrogen and defective surface should be attributed to the fact that the electronic structures of Mg (0001) surface are modified by an Mg vacancy, and the bonding electrons of the topmost layer Mg atoms are transferred from low energy range to Fermi level, which is in favor of improving the surface activity of Mg (0001) surface.

  6. Study on H atoms diffusion and adsorption properties of MgH2-V systems

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    Based on experimental results that VH0.81/MgH2 interface was found during the process of mechanically milling MgH2+5at.%V nanocomposite, H atoms diffusion and adsorption properties of MgH2-V systems have been investigated by using a first-principles plane-wave pseudopotential method based on the density functional theory. The results are as follows. When VH/MgH2 interface is formed due to V alloying MgH2 phase, the vacancy formed by H atoms near VH phase region is more stable than that without V alloying, while vacancy near MgH2 phase region is less stable than that without V alloying. During the process of H atoms diffusion after V alloying, the max migration barrier energy of H atoms in MgH2-V systems is reduced compared with that of MgH2 phase, which means that H atoms diffuse easily. When H diffuses into VH from MgH2 across VH/MgH2 interface, among three substitutions such as the replacement of H for V vacancy, or interstitial site or V atoms, the replacement of H for V vacancy has the strongest diffusion ability, next interstitial site, and finally V atoms site. As far as H adsorbed on different surfaces of VH phase is concerned, physical adsorption is carried out more easily than chemical adsorption, and the behavior of H atoms adsorbed on the surface near VH phase region can be found more easily than that near MgH2 phase region.

  7. Properties and characterization of Au3+-adsorption by mycelial waste of Streptomyces aureofaciences

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    Mycelial waste of Streptomyces aureofaciences procured from the aureomycin fermentation industry is used as biosorbent for Au3+. The properties of Au3+ adsorption by the mycelial waste are studied. The results indicate that the optimum pH value of Au3+ adsorption is 3.5. The biosorption is a rapid and non-temperature-dependent process. The biosorptive capacity with 45.6 mg/g and efficiency with 91.2% are achieved under the conditions of pH 3.5 and 30℃ for 45 min, in which the ratio is 50 mg/g dry weight for the concentrations of initial Au3+ and the myceliai waste. The Au3+ ions adsorbed on the mycelial waste can be eluted. The observation in a transmission electron microscope shows that the Au3+ ions can be reduced to Au particles by the mycelial waste and the Au0 can become gold crystals with different forms and sizes. X-ray photoelectron spectroscopy analysis further proves that the Au3+ can be reduced to Au0 by the mycelial waste.

  8. Optical, structural and adsorption properties of zinc peroxide/hydrogel nanohybrid films

    International Nuclear Information System (INIS)

    Hybrid nanofilms from zinc-peroxide/poly(acrylamide) (ZnO2/PAAm) and zinc-peroxide/poly(N-isopropyl-acrylamide) (ZnO2/PNIPAAm) were prepared using the photopolymerization procedure. The thin layers were prepared by the combination of the Layer-by-Layer (LbL) self-assembly method and photopolymerization using UV light in every step of the procedure. The hybrid multilayer films consisting of layers of zinc peroxide nanoparticles and hydrogel alternating in a sandwich-like fashion with thicknesses of 65-246 nm. The chemical structures of the hybrid films were investigated by FTIR spectroscopy, their morphology was studied by atomic force microscopy (AFM). The build up of the films was studied by measuring the optical reflection spectrum, and we have calculated the refractive index and layer thickness of the hybrid layers using simulating software. The adsorption properties of the ZnO2/hydrogel nanohybrid composite networks were investigated by measuring water and ethanol vapour adsorption by a quartz crystal microbalance (QCM). It was established that on partially hydrophobic ZnO2/PNIPAAm hybrids the adsorbed amounts were lower, against the hydrophilic ZnO2/PAAm film the vapour amount was higher. These results correspond to those of the bulk gel swelling results.

  9. ADSORPTION PROPERTIES OF NICKEL-BASED MAGNETIC ACTIVATED CARBON PREPARED BY PD-FREE ELECTROLESS PLATING

    Directory of Open Access Journals (Sweden)

    Boyang Jia

    2011-02-01

    Full Text Available Nickel-based magnetic activated carbon was synthesized from coconut shell activated carbon by electroless plating with palladium-free activation. The effect of plating solution volume on metallic ratio and adsorption capacity were evaluated. The effect of metallic ratio on specific area, pore volume, and magnetic properties were investigated. The morphologies of activated carbon before and after plating were observed by SEM, and the composition of the layer was analyzed by EDS analysis. The results showed that the metallic ratio was increased with the increase of the plating solution volume. The magnetic activated carbon showed high adsorption capacity for methylene blue and a high iodine number. Those values reached 142.5 mg/g and 1035 mg/g, respectively. The specific area and pore volume decreased from 943 m2/g to 859 m2/g and 0.462 ml/g to 0.417 ml/g, respectively. And the layer was more compact and continuous when the metallic ratio reached 16.37 wt.%. In the layer, there was about 97 wt.% nickel and 3 wt.% phosphorus, which indicates that the layer was a low-phosphorus one. At the same time, magnetism was enhanced, making the product suitable for some special applications.

  10. Optical, structural and adsorption properties of zinc peroxide/hydrogel nanohybrid films

    Energy Technology Data Exchange (ETDEWEB)

    Sebok, Daniel; Janovak, Laszlo [Department of Physical Chemistry and Materials Sciences, University of Szeged, H-6720 Szeged (Hungary); Dekany, Imre, E-mail: i.dekany@chem.u-szeged.hu [Department of Physical Chemistry and Materials Sciences, University of Szeged, H-6720 Szeged (Hungary); Supramolecular and Nanostructured Materials Research Group of the Hungarian Academy of Sciences, H-6720 Szeged, Aradi v.t. 1. (Hungary)

    2010-06-15

    Hybrid nanofilms from zinc-peroxide/poly(acrylamide) (ZnO{sub 2}/PAAm) and zinc-peroxide/poly(N-isopropyl-acrylamide) (ZnO{sub 2}/PNIPAAm) were prepared using the photopolymerization procedure. The thin layers were prepared by the combination of the Layer-by-Layer (LbL) self-assembly method and photopolymerization using UV light in every step of the procedure. The hybrid multilayer films consisting of layers of zinc peroxide nanoparticles and hydrogel alternating in a sandwich-like fashion with thicknesses of 65-246 nm. The chemical structures of the hybrid films were investigated by FTIR spectroscopy, their morphology was studied by atomic force microscopy (AFM). The build up of the films was studied by measuring the optical reflection spectrum, and we have calculated the refractive index and layer thickness of the hybrid layers using simulating software. The adsorption properties of the ZnO{sub 2}/hydrogel nanohybrid composite networks were investigated by measuring water and ethanol vapour adsorption by a quartz crystal microbalance (QCM). It was established that on partially hydrophobic ZnO{sub 2}/PNIPAAm hybrids the adsorbed amounts were lower, against the hydrophilic ZnO{sub 2}/PAAm film the vapour amount was higher. These results correspond to those of the bulk gel swelling results.

  11. SURFACE MODIFICATION OF TITANIUM FILMS WITH SODIUM ION IMPLANTATION: SURFACE PROPERTIES AND PROTEIN ADSORPTION

    Institute of Scientific and Technical Information of China (English)

    K. Y. Cai

    2007-01-01

    Sodium implanted titanium films with different ion doses were characterized to correlate their ion implantation parameters. Native titanium films and ion implanted titanium films were characterized with combined techniques of X-ray photoelectron spectroscopy (XPS), atomic force microscopy (AFM), and light microscopy (LM). The surface presented increased sodium concentration on treated titanium films with ion dose increasing, except for the group with the highest ion dose of 4× 1017 ions/cm2. XPS depth profiling displayed that sodium entered titanium film around 25-50 nm depth depending on its implantation ion dose. AFM characterization showed that sodium ion implantation treatment changed the surface morphology from a relatively smooth titanium film to rough surfaces corresponding to different implantation doses.After sodium implantation, implanted titanium films presented big particles with island structure morphology. The surface morphology and particle growth displayed the corresponding trend.Fibrinogen adsorption on these titanium films was performed to correlate with the surface properties of treated titanium films. The results show that protein adsorption on ion-implanted samples with dose of 2 × 1017 and 4 × 1017 are statistically higher (p < 0. 01) than samples treated with dose of 5×1016 and 1 ×1017, as well as the control samples.

  12. Effect of support structure on CO2 adsorption properties of pore-expanded hyperbranched aminosilicas

    KAUST Repository

    Drese, Jeffrey H.

    2012-03-01

    Hyperbranched aminosilica (HAS) CO 2 adsorbents are prepared by the ring-opening polymerization of aziridine from SBA-15 mesoporous silica, as in the original synthesis of HAS materials, as well as over an array of new support materials with substantially larger average pore diameters to elucidate the effect of support porosity on final adsorbent properties. Pore-expanded hyperbranched aminosilica (PEHAS) CO 2 adsorbents are prepared from several different pore-expanded, ordered mesoporous silicas including pore-expanded SBA-15, mesocellular foam, and a large-pore commercial silica. The effect of the nature of the silica support is determined by examining the degree of aziridine polymerization and the CO 2 adsorption kinetics and capacities of the resulting organic/inorganic hybrid materials. Comparisons are made to non-pore-expanded SBA-15 based HAS adsorbents, reported previously, where pores become blocked at higher amine loadings. The PEHAS materials unexpectedly possess lower amine loadings than the previously reported HAS materials and do not exhibit pore blocking. The use of acetic acid as a catalyst during PEHAS synthesis only marginally increases amine loading. The adsorption kinetics of PEHAS adsorbents are similar to HAS adsorbents with low amine loadings and do not show the detrimental effects of pore-blocking. However, the inability to synthesize PEHAS adsorbents with high amine loadings via this approach limits the total amount of CO 2 captured per gram of material, compared to HAS adsorbents with high amine loadings. © 2011 Elsevier Inc. All rights reserved.

  13. Synthesis and characterization of Ag nanoparticles decorated mesoporous sintered activated carbon with antibacterial and adsorptive properties

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Wenxia; Xiao, Kaijun, E-mail: fekjxiao@scut.edu.cn; He, Tinglin; Zhu, Liang, E-mail: zhuliang@scut.edu.cn

    2015-10-25

    In this study, the sliver nanoparticles (AgNPs) immobilized on the sintered activated carbon (Ag/SAC) were synthesized by the ultrasonic-assisted impregnation method and were characterized by scanning electron microscope (SEM), X-ray diffraction (XRD) and nitrogen adsorption. SEM showed that the AgNPs were well embedded in the SAC and immersion time had an important influence on final morphologies of AgNPs. Longer immersing duration caused significant aggregation of the AgNPs. The XRD data revealed that the successful synthesis of AgNPs on the SAC and immobilizing AgNPs on sintered active carbon did not change the crystalline degree of SAC. Texture characteristics were determined by analysis of the N{sub 2}/77 K isotherms. The minimum inhibitory concentration (MIC) of Ag/SAC against Escherichia coli (DH5α) and Staphyloccocus aureus (ATCC 29213) was evaluated by a broth dilution method. MICs such as 5 mg/L (against E. coli) and 10 mg/L (against S. aureus) suggest that Ag/SAC have predominant antibacterial activity compared to active carbon. - Highlights: • Sintered active carbon (SAC) was coated with Ag via a facile approach. • The Ag/SAC exhibit good adsorption properties and excellent antibacterial effects. • The Ag/SAC was durable and stable in the application of water purification.

  14. Modification process optimization, characterization and adsorption property of granular fir-based activated carbon

    International Nuclear Information System (INIS)

    Highlights: • Granular fir-based activated carbon (GFAC) was modified with H2O2. • Orthogonal array design method was used to optimize the modification process. • Optimized parameters were: aqueous H2O2 concentration 1.0 mol l−1, modification temperature and time 30.0 °C and 4.0 h. • Adsorption capacity of the modified GFAC increased by 500.0% (caramel), 59.7% (methylene blue), 32.5% (phenol), and 15.1% (I2). • The pore structure parameters and surface oxygen groups changed in the modified GFAC. - Abstract: Granular fir-based activated carbon (GFAC) was modified with H2O2, and orthogonal array experimental design method was used to optimize the process. The properties of the original and modified GFAC were characterized by N2 adsorption–desorption isotherms, Brunauer–Emmett–Teller (BET) equation, Barett–Joyner–Halenda (BJH) equation, field emission scanning electron microscopy (FESEM), and Fourier transform infrared spectroscopy (FT-IR) analysis, etc. When 10.00 g of GFAC with particle size of 0.25–0.85 mm was modified by 150.0 ml of aqueous H2O2 solution, the optimized conditions were found to be as follows: aqueous H2O2 solution concentration 1.0 mol·l−1, modification temperature 30.0 °C, modification time 4.0 h. Modified under the optimized conditions, decolonization of caramel, methylene blue adsorption, phenol adsorption and iodine number of the modified GFAC increased by 500.0%, 59.7%, 32.5%, and 15.1%, respectively. The original and optimally modified GFAC exhibited adsorption isotherms of hybrid Type I–IV isotherms with H4 hysteresis. BET surface area, micropore area, total pore volume, micropore volume, and microporosity of the modified GFAC increased by 7.33%, 11.25%, 3.89%, 14.23%, 9.91%, respectively. Whereas the average pore width decreased by 3.16%. In addition, the amount of surface oxygen groups (such as carbonyl or carboxyl) increased in the modified GFAC

  15. Activated Carbon Adsorption Properties of the Residual Matters in Textile Dyeing and Printing Secondary Effluent

    Institute of Scientific and Technical Information of China (English)

    TIAN Qing; LI Fang; LIU Fang; YANG Bo; CHEN Ji-hua

    2008-01-01

    The research employed the adsorption isotherm measurement, the batch kinetic adsorption and the rapid small-scale carbon column test (RSSCT) to find out the characteristics and main impacting factors of granular activated carbon (GAC) adsorption, in treating the textile dyeing-printing/polyester alkali de-weighting secondary effluent (TSE). The adsorption affinities and capacities for the organics surrogated by CODCr, color and UV254 (UV absorbency at λ= 254 nm) predicted by isotherm, small-scale-fixed bed were discussed. Adsorption rates for CODCr, color and UV254 are much different and carbon particle size dependent. The color adsorption rate and capacity should be taken as the main consideration factors in designing bio-activated carbon filter(BACF). The breakthrough of GAC adsorption column is mainly influenced by the low MW readily adsorbable organics in TSE. UVm is a good adsorption breakthrough indicator. The study provides References for BACFs' design and operation control in textile secondary effluent (TSE) tertiary treatment.

  16. Surface modification of spinel λ-MnO2 and its lithium adsorption properties from spent lithium ion batteries

    International Nuclear Information System (INIS)

    Highlights: • A method is designed to synthesize a λ-MnO2 ion-sieve for lithium ions adsorption. • Ultrasonic treatment with acid is highly efficient for lithium ions extraction. • Surface modification by CeO2 is used to improve the adsorption capacity. • A 0.5 wt.% CeO2-coated ion-sieve shows the best adsorption properties. • λ-MnO2 ion-sieves are promising for recovering scarce lithium resources. - Abstract: Spinel λ-MnO2 ion-sieves are promising materials because of their high selectivity toward lithium ions, and this can be applied to the recovery of lithium from spent lithium ion batteries. However, manganese dissolution loss during the delithiation of LiMn2O4 causes a decrease in adsorption capacity and poor cycling stability for these ion-sieves. To improve the lithium adsorption properties of λ-MnO2 ion-sieves, surface modification with a CeO2 coating was studied using hydrothermal-heterogeneous nucleation. The structure, morphology and composition of the synthesized materials were determined by XRD, SEM, TEM and EDS. The effect of hydrothermal synthesis conditions and the amount of CeO2 coating on the adsorption performance of λ-MnO2 were also investigated. A 0.5 wt.% CeO2-coated ion-sieve was synthesized by heating at 120 °C for 3 h and it had better adsorption properties than the bare samples. The effect of ultrasonic treatment on the lithium extraction ratio from LiMn2O4 upon acid treatment at various temperatures was studied and the results were compared with conventional mechanical stirring. We found that ultrasonic treatment at lower temperature gave almost the same maximum lithium extraction ratio and was more efficient and economic

  17. Quantifying differences in the impact of variable chemistry on equilibrium uranium(VI) adsorption properties of aquifer sediments

    Science.gov (United States)

    Stoliker, Deborah L.; Kent, Douglas B.; Zachara, John M.

    2011-01-01

    Uranium adsorption-desorption on sediment samples collected from the Hanford 300-Area, Richland, WA varied extensively over a range of field-relevant chemical conditions, complicating assessment of possible differences in equilibrium adsorption properties. Adsorption equilibrium was achieved in 500-1000 h although dissolved uranium concentrations increased over thousands of hours owing to changes in aqueous chemical composition driven by sediment-water reactions. A nonelectrostatic surface complexation reaction, >SOH + UO22+ + 2CO32- = >SOUO2(CO3HCO3)2-, provided the best fit to experimental data for each sediment sample resulting in a range of conditional equilibrium constants (logKc) from 21.49 to 21.76. Potential differences in uranium adsorption properties could be assessed in plots based on the generalized mass-action expressions yielding linear trends displaced vertically by differences in logKc values. Using this approach, logKc values for seven sediment samples were not significantly different. However, a significant difference in adsorption properties between one sediment sample and the fines (Kc uncertainty were improved by capturing all data points within experimental errors. The mass-action expression plots demonstrate that applying models outside the range of conditions used in model calibration greatly increases potential errors.

  18. Evaluation of Protein Adsorption on Atmospheric Plasma Deposited Coatings Exhibiting Superhydrophilic to Superhydrophobic Properties

    OpenAIRE

    Stallard, Charlie P.; McDonnell, Kevin; Onayemi, O. D.; et al.

    2012-01-01

    Protein adsorption is one of the key parameters influencing the biocompatibility of medical device materials. This study investigates serum protein adsorption and bacterial attachment on polymer coatings deposited using an atmospheric pressure plasma jet system. The adsorption of bovine serum albumin and bovine fibrinogen (Fg) onto siloxane and fluorinated siloxane elastomeric coatings that exhibit water contact angles (θ) ranging from superhydrophilic (θ 150°) ...

  19. Structural and Electronic Properties of Folic Acid Adsorption on the Carbon Nanotubes: A Density Functional Theory Study

    Directory of Open Access Journals (Sweden)

    Shahla Hamedani

    2015-03-01

    Full Text Available In this study, we studied the adsorption behavior of folic acid on the (5,0 zigzag and (5,5 armchair single-walled carbon nanotube (SWCNT by Density Functional Theory (DFT. Geometry optimizations were carried out at the B3LYP/6-31 G* level of theory using the Gaussian 09 suite of programs. The adsorption energies, the quantum molecular descriptors analysis and the structural changes at the adsorption site are indicative of chemisorption (adsorption energy -31.673 kcal/mol on the zigzag SWCNT surface, while the adsorption is physical (adsorption energy -9.70 kcal/mol in nature on the armchair SWCNT surface. The density of the states (DOS Plots, Natural bond orbital (NBO analysis, and HOMO and LUMO are witness to the substantial changes in the electronic properties of the SWCNT systems after the attachment adsorbed species with the tube surface. These results are extremely relevant in order to diagnosis the potential applications of carbon nanotubes as drug delivery systems.

  20. Physical and Hydrodynamic Properties of Spherical Cellulose—Titanium Dioxide Composite Matrix for Expanded Bed Adsorption

    Institute of Scientific and Technical Information of China (English)

    雷引林; 林东强; 姚善泾; 刘坐镇; 朱自强

    2003-01-01

    Expanded bed adsorption (EBA) has been widely used in industrial downstream bioprocessing,Solid matrix is the principal pillar supporting the successful application of EBA.A novel spherical ceelulose-titanium dioxide composite matrix was prepared through the method of water-in-oil suspension thermal regeneration.Its typical physical properties were wet density 1.18g.cm-3,,diameters in the range of 100-300μm ,porosity 85.5%,and water content 72.3%.Expansion characteristics and liquid mixing performance of the matrix in expanded bed were investigated using water and 10% (by mass )glycerol solution as mobile phases,The results indicate that the custom-assembled matrix has a stable flow hydrodynamics and exhibits the same degree of liquid-phase mixing or column efficiency as the commercially available Streamline adsorbent.

  1. Structural and elastic properties and stability characteristics of oxygenated carbon nanotubes under physical adsorption of polymers

    Energy Technology Data Exchange (ETDEWEB)

    Ansari, R., E-mail: r_ansari@guilan.ac.ir [Department of Mechanical Engineering, University of Guilan, P.O. Box 3756, Rasht (Iran, Islamic Republic of); Ajori, S. [Department of Mechanical Engineering, University of Guilan, P.O. Box 3756, Rasht (Iran, Islamic Republic of); Rouhi, S. [Department of Mechanical Engineering, Langroud Branch, Islamic Azad University, Langroud (Iran, Islamic Republic of)

    2015-03-30

    Highlights: • Buckling of functionalized CNTs under physical adsorption of polymer is studied. • Molecular dynamics simulations are employed for the study. • Values of the critical buckling load and critical strain are shown to increase. • Values of Young's modulus and their variations are dependent on adsorbed polymer type. - Abstract: The importance of covalent and non-covalent functionalization approaches for modification the properties of carbon nanotubes is being more widely recognized. To this end, elastic properties and buckling behavior of oxygenated CNT with atomic oxygen and hydroxyl under physical adsorption of PE (Polyethylene) and PEO (Poly (ethylene oxide)) are determined through employing the molecular dynamics (MD) simulations. The results demonstrate that non-covalent bonding of polymer on the surface of oxygenated CNT causes reductions in the variations of critical buckling load and critical strain compared to oxygenated CNTs. Critical buckling load and critical strain of oxygenated CNT/polymer are higher than those of oxygenated CNT. Also, it is demonstrated that critical buckling load and critical strain values in the case of oxygenated CNT/polymer are independent of polymer type unlike the value of Young's modulus. It is shown that variations of Young's modulus decrease as PE adsorbed on the surface of oxygenated CNT. Moreover, the presence of oxygen atom on PEO chain leads to bigger variations of Young's modulus with weight percentage of chemisorbed component, i.e. atomic oxygen and hydroxyl. It is also demonstrated that Young's modulus reduces more considerably in the presence of PEO chain compared to PE one.

  2. Adsorption behavior and adhesive properties of biopolyelectrolyte multilayers formed from cationic and anionic starch.

    Science.gov (United States)

    Johansson, Erik; Lundström, Lisa; Norgren, Magnus; Wågberg, Lars

    2009-07-13

    Cationic starch (D.S. 0.065) and anionic starch (D.S. 0.037) were used to form biopolyelectrolyte multilayers. The influence of the solution concentration of NaCl on the adsorption of starch onto silicon oxide substrates and on the formation of multilayers was investigated using stagnation point adsorption reflectometry (SPAR) and quartz crystal microbalance with dissipation (QCM-D). The wet adhesive properties of the starch multilayers were examined by measuring pull-off forces with the AFM colloidal probe technique. It was shown that polyelectrolyte multilayers (PEM) can be successfully constructed from cationic starch and anionic starch at electrolyte concentrations of 1 mM NaCl and 10 mM NaCl. The water content of the PEMs was approximately 80% at both electrolyte concentrations. However, the thickness of the PEMs formed at 10 mM NaCl was approximately twice the thickness formed at 1 mM NaCl. The viscoelastic properties of the starch PEMs, modeled as Voigt elements, were dependent on the polyelectrolyte that was adsorbed in the outermost layer. The PEMs appeared to be more rigid when capped by anionic starch than when capped by cationic starch. The wet adhesive pull-off forces increased with layer number and were also dependent on the polyelectrolyte adsorbed in the outermost layer. Thus, starch PEM treatment has a large potential for increasing the adhesive interaction between solid substrates to levels higher than can be reached by a single layer of cationic starch. PMID:21197962

  3. Adsorption of ionic liquid onto halloysite nanotubes: Thermal and mechanical properties of heterophasic PE-PP copolymer nanocomposites

    Science.gov (United States)

    Bischoff, E.; Simon, D. A.; Liberman, S. A.; Mauler, R. S.

    2016-03-01

    The surface adsorption of inorganic clays with ionic liquids has attracted much attention due to improve the interaction of hydrophilic clay with the hydrophobic polymers. However, successful organic adsorption strongly depends on the characteristics of ionic liquid (anion, chain size and concentration), and the reaction conditions (as polarity of solvent). In this study, such factors were analyzed and correlated with morphology, thermal and mechanical properties of the nanocomposites. The heterophasic ethylene-propylene copolymer nanocomposites were prepared by melt intercalation method in a twin screw co-rotating extruder. The halloysite nanotubes (HNT) was used as filler - natural and modified with different ionic liquids. The results showed that a better distribution and dispersion of the nanoparticles was achieved in the samples with modified HNT (m-HNT) and was more significant when the ionic liquid adsorption was conducted in a less polar solvent. The thermal stability of the nanocomposites with m- HNT was higher compared to the neat CP. Additionally, the better balance in the mechanical properties was obtained by the use of the more hydrophobic ionic liquid and higher concentration with improve of 27% in the Young Modulus without loss in the impact properties at room temperature. These superior behaviors of ionic liquid adsorption products exhibit properties suitable for many industrial applications.

  4. Dynamic adsorption properties of xenon on activated carbons and their structure characterization

    International Nuclear Information System (INIS)

    Background: In recent years, adsorption of radioactive xenon by activated carbon has been increasingly applied to the treatment of off-gas in nuclear power project. Though pore structure of activated carbon has a great impact on its dynamic adsorption coefficients for xenon, the concerned research is rare. Purpose: It is very necessary to figure out the relationship between the pore structure and the dynamic adsorption coefficients for the purpose of the selection and development of activated carbon. Methods: In this study, the dynamic adsorption coefficients of xenon on four kinds of activated carbons were measured on a dynamic adsorption platform under the condition of 25℃, OMPa (gauge pressure). And these four kinds of activated carbons were characterized by nitrogen adsorption and SEM. Results: The results show that the activated carbon of JH12-16 with the specific surface area of 991.9 m2·g-1 has the largest xenon dynamic adsorption coefficient among these activated carbons. Conclusions: The dynamic adsorption coefficient of xenon on activated carbon doesn't increase with the specific surface area or the pore volume. The mesopore and macropore only play the role of passageway for xenon adsorption. The most suitable pore for xenon adsorption is the pore with the pore size ranged from 0.55 to 0.6 nm. (authors)

  5. Interfacial properties of asymmetrically functionalized citrate-stabilized gold and silver nanoparticles related to molecular adsorption

    Science.gov (United States)

    Park, Jong-Won

    A detailed understanding of the conformation of adsorbed molecules and regional surface functionalization of metal nanoparticles (MNPs) is challenging for nanometer-size (10 -- 100 m) materials and necessary for fundamental studies and applications. The studies are motivated by open questions related to surface chemistry of noble MNPs. Although citrate-stabilized gold NPs (AuNPs) have been widely used, the citrate layer is not well-understood. Thiols have been suggested to displace citrate anions adsorbed on metal surfaces due to strong gold-sulfur interaction, but quantitative experimental evidence of the extent of ligand-exchange has not been reported. Whereas asymmetrically-functionalized AuNPs are utilized for nanoparticle assembly due to the interparticle coupling of localized surface plasmons, the interface between asymmetric nanoparticles in single assemblies has not been studied. Noble MNPs with sizes smaller than citrate-stabilized AuNPs also need to be surface-modified for stability in water for biological applications. The dissertation presents investigations of the chemical and physical properties of gold and silver NPs (AgNPs) related to ligand adsorption at the metal surface. Firstly, self-assembled layers of citrate adsorbed on AuNP (111), (110), and (100) surfaces were proposed, based on geometric considerations and spectroscopic investigations by infrared (IR) and X-ray photoelectron spectroscopy (XPS). Adsorption characteristics of citrate are the unique structure of adsorbed species, intermolecular interactions through hydrogen bonds and van der Waals attractions, bilayer formation, surface coverage, nanoparticle-stabilization role, and chirality. Secondly, IR and XPS studies showed coadsorption of thiolate on the surface of citrate-stabilized AuNPs. Steric, chelating effects and intermolecular interactions are the origins of the strong adsorption of citrate on AuNP surfaces. Surface coverage was determined from XPS analyses. Thirdly, an

  6. Three-Dimensional Assembly of Yttrium Oxide Nanosheets into Luminescent Aerogel Monoliths with Outstanding Adsorption Properties.

    Science.gov (United States)

    Cheng, Wei; Rechberger, Felix; Niederberger, Markus

    2016-02-23

    The preparation of macroscopic materials from two-dimensional nanostructures represents a great challenge. Restacking and random aggregation to dense structures during processing prevents the preservation of the two-dimensional morphology of the nanobuilding blocks in the final body. Here we present a facile solution route to ultrathin, crystalline Y2O3 nanosheets, which can be assembled into a 3D network by a simple centrifugation-induced gelation method. The wet gels are converted into aerogel monoliths of macroscopic dimensions via supercritical drying. The as-prepared, fully crystalline Y2O3 aerogels show high surface areas of up to 445 m(2)/g and a very low density of 0.15 g/cm(3), which is only 3% of the bulk density of Y2O3. By doping and co-doping the Y2O3 nanosheets with Eu(3+) and Tb(3+), we successfully fabricated luminescent aerogel monoliths with tunable color emissions from red to green under UV excitation. Moreover, the as-prepared gels and aerogels exhibit excellent adsorption capacities for organic dyes in water without losing their structural integrity. For methyl blue we measured an unmatched adsorption capacity of 8080 mg/g. Finally, the deposition of gold nanoparticles on the nanosheets gave access to Y2O3-Au nanocomposite aerogels, proving that this approach may be used for the synthesis of catalytically active materials. The broad range of properties including low density, high porosity, and large surface area in combination with tunable photoluminescence makes these Y2O3 aerogels a truly multifunctional material with potential applications in optoelectronics, wastewater treatment, and catalysis. PMID:26756944

  7. Effect of process parameters on the morphology and adsorption properties of nanocrystalline boehmite

    Directory of Open Access Journals (Sweden)

    Obrenović Zoran

    2014-01-01

    Full Text Available In the last decade, exploration of transition alumina phases with good adsorption properties has attracted a great research interest from both a fundamental and a practical point of view. The transition phases of alumina are metastable polymorphs of aluminum oxide formed through the thermal dehydration of aluminum trihydroxide and aluminum oxyhydroxide. Powder X-ray diffraction (XRD, Fourier-transformed infrared spectroscopy (FT-IR, scanning electron microscopy (SEM and low-temperature nitrogen absorption studies were employed to trace the formation of the transition phases of alumina. In this work transition alumina powders were synthesized starting from sodium aluminate solution prepared from Bayer liquor. The neutralization of sodium aluminate solution was performed with the use of sulphuric acid, while glucose was added in the starting solution. In this way, the single phase nanocrystalline boehmite was obtained. As-synthesized boehmite powders have high surface area (above 360 m2/g and the average crystallite size less than 5 nm. The results showed that the properties of the powders (structure, morphology are strongly influenced by the initial pH value of sodium aluminate solution, as well as by the duration of neutralization step. [Projekat Ministarstva nauke Republike Srbije, br. III 45021

  8. Relationship between Production Method and Adsorption Property of Charcoal; Mokutan no seizo hoho to kyuchaku tokusei no kankei

    Energy Technology Data Exchange (ETDEWEB)

    Abe, Ikuo.; Iwasaki, Satoshi. [Osaka Municiipal Technical Research Institute, Osaka (Japan); Iwata, Yoshimi.; Kominami, Hiroshi.; Kera, Yoshiya. [Kinki University, Osaka (Japan). Faculty of Science and Engineering

    1998-12-31

    Charcoals were prepared from Japanese cypress (C. obtusa) and Japanese Oak (Q. mongolica) by three carbonization methods, (a) in a nitrogen stream, (b) in an air stream, (c) in a container with cover. The relationship between the carbonization methods and the adsorption properties and the following results were obtained. Regardless of the carbonization method or the kind of wood used, the surface of charcoals prepared at low temperature was acidic and that of charcoals prepared at high temperature basic. The surface of charcoals prepared by method (c) showed the highest acidity. When benzene, iodine and phenol were adsorbed for short periods onto charcoals prepared by methods (a) and (c), the charcoal prepared at 600 degree C had the largest mean pore size, and also showed the fastest adsorption rate and the highest adsorption capacity. Of the charcoals prepared by method (b), the charcoal prepared at 900 degree C had the highest absorption capacity. The charcoal prepared at 1000 degree C showed a decrease in adsorption capacity because of thermal shrinkage of the pores. For all methods, adsorption capacity for water vapor was lowest in the charcoal prepared at 600 degree C. However, the amount of water vapor desorbed when humidity decreased was highest in the charcoal prepared at 600 degree C. It was found that the 600 degree C charcoal is the best use in humidity-control. (author)

  9. Thermo-physical properties of silica gel for adsorption desalination cycle

    KAUST Repository

    Thu, Kyaw

    2013-02-01

    Thermo-physical properties, surface characteristics and water vapor uptake capacity are key parameters in the selection of adsorbent for an adsorption desalination (AD) cycle. In the AD cycles, silica gel is used as adsorbent due to their high water vapor uptake capacity, reliability, repeatability and inexpensiveness as compared to other adsorbents. Three types of commercially available silica gels (Type-RD 2560,Type-A5BW and Type-A++) are investigated using a surface characteristic analyzer and their thermo-physical properties are evaluated using several analysis methods. The instrument used in this investigation employs the static volumetric method with liquid Nitrogen at 77 K as the filing fluid. The surface area of each adsorbent is studied using Brunauer-Emmett-Teller (BET) method whilst the pore size distribution (PSD) analysis is conducted with the Non-Local Density Functional Theory (NLDFT). It is observed that the Type-A++ silica gel (granular type) possesses the highest surface area of 863.6 m2/g amongst the three parent silica gels studied. It has a two-maxima or bimodal distribution pattern where the pore diameters are distributed mostly between 10 Å and 30 Å. Water vapor uptake capacity of silica gels are studied with water vapor dosage apparatus and the results show that the Type-A++ silica gel exhibits a highest equilibrium uptake at 537 cm3/g. These thermo-physical properties are essential for the design and the numerical simulation of AD cycles. © 2012 Published by Elsevier Ltd.

  10. STUDY ON THE PROPERTIES OF DIFFERENT ACTIVATED CARBON FIBERS AND THEIR ADSORPTION CHARACTERISTICS FOR FORMALDEHYDE

    Institute of Scientific and Technical Information of China (English)

    H.Q. Rong; Z.Y. Ryu; J.T. Zheng

    2001-01-01

    Porous structure and surface chemistry of activated carbon fibers obtained by differ-ent precursors and activation methods were investigated. Adsorption isotherms werecharacterized by nitrogen adsorption at 77K over a relative pressure range from 10 6to 1. The regularization method according to Density Functional Theory (DFT) wasemployed to calculate the pore size distribution in the samples. Their specific surfaceareas were calculated by BET method, micropore volume and microporous specificsurface area calculated by t-plot method and MPD by Horvath-Kawazoe equation. Mi-cropore volume of rayon-based ACF was higher than that of other samples. The staticand dynamic adsorption capacity for formaldehyde on different ACFs was determined.The results show that steam activated Rayon-based A CFs had higher adsorption capac-ity than that of steam and KOH activated PAN-A CFs. Breakthrough curves illustratedthat Rayon-ACFs had longer breakthrough time, thus they possessed higher adsorp-tion capacity for formaldehyde than that of PAN-ACFs. The entire sample had smalladsorption capacity and short breakthrough time for water. Rayon-A CFs had exccl-lent adsorption selectivity for formaldehyde than PAN-ACFs. And the samples withhigh surface areas had relatively high adsorption capacity for formaldehyde. Elementaicontent of different A CFs were performed. Rayon-based A CFs contained more oxygenthan PAN-ACFs, which may be attributed to their excellent adsorption capacity forformaldehyde.

  11. Synthesis of corrosion inhibitors from corn oil fatty acids and study of their adsorption properties

    International Nuclear Information System (INIS)

    The imidazoline derivatives were synthesized from corn oil fatty acids and triethylenetetramine. The corrosion inhibition efficiency studies of these imidazolines were performed in H2S solutions by gravimetric method. The adsorption behaviour of the compounds obeys the Langmuir isotherm and the interaction between the inhibitor molecule and the metal surface is a strong chemical reaction with high Gibbs free adsorption energy

  12. Oxygen adsorption and electronic transport properties of Fe-substituted YBaCo{sub 4}O{sub 7} compounds

    Energy Technology Data Exchange (ETDEWEB)

    Hao, Haoshan, E-mail: hao@haue.edu.cn [School of Science, Henan Institute of Engineering, Zhengzhou 451191 (China); He, Qinglin [School of Science, Jiaozuo Teacher' s College, Jiaozuo 454001 (China); Cheng, Yongguang; Zhao, Limin [School of Science, Henan Institute of Engineering, Zhengzhou 451191 (China)

    2014-05-01

    Graphical abstract: - Highlights: • The conduction mechanism of YBaCo{sub 4}O{sub 7} system was established. • The effect of Fe substitution on the electronic transport was discussed. • The effect of oxygen adsorption/desorption processes on the transport properties was investigated. - Abstract: YBaCo{sub 4−x}Fe{sub x}O{sub 7} (0.0 ≤ x ≤ 0.8) samples were prepared by the solid-state reaction method and the effect of Fe substitution and oxygen adsorption/desorption on the electronic transport properties was investigated from room temperature to 900 °C. Fe for Co substitution results in a slight decline in the oxygen storage capacity at lower temperature (200–400 °C) and an increase of the phase-decomposition temperature at higher temperature (700–900 °C). Both the hole concentration and mobility are reduced in the Fe-containing compositions. Electrical resistivity, Seebeck coefficient, and conduction activation energy increase with the increasing Fe content. A close correlativity between oxygen adsorption and electronic transport behavior was observed in YBaCo{sub 4−x}Fe{sub x}O{sub 7} system. Oxygen adsorption decreases the electrical resistivity and Seebeck coefficients because of the increase of hole concentration at lower temperature and the phase decomposition at higher temperature.

  13. The relationship between formate adsorption energy and electronic properties: A first principles density functional theory study

    Institute of Scientific and Technical Information of China (English)

    MORIKAWA; Yoshitada; NAKAMURA; Junji

    2009-01-01

    First principles density functional theory calculations have been performed for the chemisorption of formate adsorption on some metal surfaces. For the most stable adsorption site of short-bridge, the calculated formate adsorption energy follows the order of Au(110) < Ag(110) < Cu(110) < Pd(110) < Pt(110) < Ni(110) < Rh(110) < Fe(100) < Mo(100), and a clear linear correlation exists between the adsorption energy and the corresponding heat of formation of metal oxides. Moreover, it has been found that the formate adsorption energy for the transition metals can be correlated well with its d-band center (εd), and the IB Group metals can be described by the coupling matrix element square (Vad2).

  14. Study of Adsorption and Flocculation Properties of Natural Clays to Remove Prorocentrum lima.

    Science.gov (United States)

    Louzao, Maria Carmen; Abal, Paula; Fernández, Diego A; Vieytes, Mercedes R; Legido, José Luis; Gómez, Carmen P; Pais, Jesus; Botana, Luis M

    2015-10-01

    High accumulations of phytoplankton species that produce toxins are referred to as harmful algal blooms (HABs). HABs represent one of the most important sources of contamination in marine environments, as well as a serious threat to public health, fisheries, aquaculture-based industries, and tourism. Therefore, methods effectively controlling HABs with minimal impact on marine ecology are required. Marine dinoflagellates of the genera Dinophysis and Prorocentrum are representative producers of okadaic acid (OA) and dinophysistoxins responsible for the diarrhetic shellfish poisoning (DSP) which is a human intoxication caused by the consumption of shellfish that bioaccumulate those toxins. In this work we explore the use of natural clay for removing Prorocentrum lima. We evaluate the adsorption properties of clays in seawater containing the dinoflagellates. The experimental results confirmed the cell removal through the flocculation of algal and mineral particles leading to the formation of aggregates, which rapidly settle and further entrain cells during their descent. Moreover, the microscopy images of the samples enable one to observe the clays in aggregates of two or more cells where the mineral particles were bound to the outer membranes of the dinoflagellates. Therefore, this preliminary data offers promising results to use these clays for the mitigation of HABs. PMID:26426051

  15. Contribution to the study of chemical and physical properties of mineral coals and mineral active coals. New method of determination of adsorption isotherms

    International Nuclear Information System (INIS)

    For a better understanding of the influence of factors which influence the coal activation process, this research thesis aims at following, step by step, the evolution of texture and chemical properties of a mineral coal submitted to a series of treatments which allow its progressive transformation into an active coal. The first part reports sample preparation and the study of chemical properties, notably surface functions. The second part addresses physical properties of samples: study of porosity by electronic microscopy, apparatus used to study gas adsorption, helium adsorption by solid surfaces at room temperature, study of the porous texture by gas adsorption

  16. Synthesis, characterization, and mercury adsorption properties of hybrid mesoporous aluminosilicate sieve prepared with fly ash

    International Nuclear Information System (INIS)

    A novel hybrid mesoporous aluminosilicate sieve (HMAS) was prepared with fly ash and impregnated with zeolite A precursors. This improved the mercury adsorption of HMAS compared to original MCM-41. The HMAS was characterized by X-ray diffraction (XRD), nitrogen adsorption–desorption, Fourier transform infrared (FTIR) analysis, transmission electron microscopy (TEM) images and 29Si and 27Al magic angle spinning nuclear magnetic resonance (MAS NMR) spectra. These showed that the HMAS structure was still retained after impregnated with zeolite A. But the surface area and pore diameter of HMAS decreased due to pore blockage. Adsorption of mercury from aqueous solution was studied on untreated MCM-41and HMAS. The mercury adsorption rate of HMAS was higher than that of origin MCM-41. The adsorption of mercury was investigated on HMAS regarding the pH of mercury solution, initial mercury concentration, and the reaction temperature. The experimental data fit well to Langmuir and Freundlich isotherm models. The Dublin–Radushkevich isotherm and the characterization show that the mercury adsorption on HMAS involved the ion-exchange mechanisms. In addition, the thermodynamic parameters suggest that the adsorption process was endothermic in nature. The adsorption of mercury on HMAS followed the first order kinetics.

  17. Synthesis, characterization, and mercury adsorption properties of hybrid mesoporous aluminosilicate sieve prepared with fly ash

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Minmin [School of Environmental Science and Engineering, Tongji University, 1239 Siping Road, Shanghai 200092 (China); Hou, Li-an, E-mail: 11liuminmin@tongji.edu.cn [School of Environmental Science and Engineering, Tongji University, 1239 Siping Road, Shanghai 200092 (China); Xi, Beidou; Zhao, Ying; Xia, Xunfeng [China Research Academy of Environmental Science, Beijing 200012 (China)

    2013-05-15

    A novel hybrid mesoporous aluminosilicate sieve (HMAS) was prepared with fly ash and impregnated with zeolite A precursors. This improved the mercury adsorption of HMAS compared to original MCM-41. The HMAS was characterized by X-ray diffraction (XRD), nitrogen adsorption–desorption, Fourier transform infrared (FTIR) analysis, transmission electron microscopy (TEM) images and {sup 29}Si and {sup 27}Al magic angle spinning nuclear magnetic resonance (MAS NMR) spectra. These showed that the HMAS structure was still retained after impregnated with zeolite A. But the surface area and pore diameter of HMAS decreased due to pore blockage. Adsorption of mercury from aqueous solution was studied on untreated MCM-41and HMAS. The mercury adsorption rate of HMAS was higher than that of origin MCM-41. The adsorption of mercury was investigated on HMAS regarding the pH of mercury solution, initial mercury concentration, and the reaction temperature. The experimental data fit well to Langmuir and Freundlich isotherm models. The Dublin–Radushkevich isotherm and the characterization show that the mercury adsorption on HMAS involved the ion-exchange mechanisms. In addition, the thermodynamic parameters suggest that the adsorption process was endothermic in nature. The adsorption of mercury on HMAS followed the first order kinetics.

  18. Scaling properties of adsorption energies for hydrogen-containing molecules on transition-metal surfaces

    DEFF Research Database (Denmark)

    Abild-Pedersen, Frank; Greeley, Jeffrey Philip; Studt, Felix;

    2007-01-01

    Density functional theory calculations are presented for CHx, x=0,1,2,3, NHx, x=0,1,2, OHx, x=0,1, and SHx, x=0,1 adsorption on a range of close-packed and stepped transition-metal surfaces. We find that the adsorption energy of any of the molecules considered scales approximately with the adsorp...... adsorption energy of the central, C, N, O, or S atom, the scaling constant depending only on x. A model is proposed to understand this behavior. The scaling model is developed into a general framework for estimating the reaction energies for hydrogenation and dehydrogenation reactions....

  19. Comparison of biocompatibility and adsorption properties of different plastics for advanced microfluidic cell and tissue culture models.

    Science.gov (United States)

    van Midwoud, Paul M; Janse, Arnout; Merema, Marjolijn T; Groothuis, Geny M M; Verpoorte, Elisabeth

    2012-05-01

    Microfluidic technology is providing new routes toward advanced cell and tissue culture models to better understand human biology and disease. Many advanced devices have been made from poly(dimethylsiloxane) (PDMS) to enable experiments, for example, to study drug metabolism by use of precision-cut liver slices, that are not possible with conventional systems. However, PDMS, a silicone rubber material, is very hydrophobic and tends to exhibit significant adsorption and absorption of hydrophobic drugs and their metabolites. Although glass could be used as an alternative, thermoplastics are better from a cost and fabrication perspective. Thermoplastic polymers (plastics) allow easy surface treatment and are generally transparent and biocompatible. This study focuses on the fabrication of biocompatible microfluidic devices with low adsorption properties from the thermoplastics poly(methyl methacrylate) (PMMA), polystyrene (PS), polycarbonate (PC), and cyclic olefin copolymer (COC) as alternatives for PDMS devices. Thermoplastic surfaces were oxidized using UV-generated ozone or oxygen plasma to reduce adsorption of hydrophobic compounds. Surface hydrophilicity was assessed over 4 weeks by measuring the contact angle of water on the surface. The adsorption of 7-ethoxycoumarin, testosterone, and their metabolites was also determined after UV-ozone treatment. Biocompatibility was assessed by culturing human hepatoma (HepG2) cells on treated surfaces. Comparison of the adsorption properties and biocompatibility of devices in different plastics revealed that only UV-ozone-treated PC and COC devices satisfied both criteria. This paper lays an important foundation that will help researchers make informed decisions with respect to the materials they select for microfluidic cell-based culture experiments. PMID:22444457

  20. Scaling properties in the adsorption of ionic polymeric surfactants on generic nanoparticles of metallic oxides by mesoscopic simulation

    CERN Document Server

    Mayoral, E

    2014-01-01

    We study the scaling of adsorption isotherms of polyacrylic dispersants on generic surfaces of metallic oxides $XnOm$ as a function of the number of monomeric units, using Electrostatic Dissipative Particle Dynamics simulations. The simulations show how the scaling properties in these systems emerge and how the isotherms rescale to a universal curve, reproducing reported experimental results. The critical exponent for these systems is also obtained, in perfect agreement with the scaling theory of deGennes. Some important applications are mentioned.

  1. Thermodynamic properties of hydrogen-water adsorption at terraces and steps of Pt(111) vicinal surface electrodes

    Science.gov (United States)

    Gómez-Marín, Ana M.; Feliu, Juan M.

    2016-04-01

    In this work, the effect of temperature on the adsorption states of Pt(111) vicinal surface electrodes in perchloric acid is studied through a thermodynamic analysis. The method allows calculating thermodynamic properties of the interface. In this framework, the concept of the generalized isotherm and the statistical thermodynamics description are applied to calculate formal entropies, enthalpies and Gibbs energies, ΔGbari0, of the adsorption processes at two-dimensional terraces and one-dimensional steps. These values are compared with data from literature. Additionally, the effect of the step density on ΔGbari0 and on the lateral interactions between adsorbed species, ωij, at terraces and steps is also determined. Calculated ΔGbari0, entropies and enthalpies are almost temperature-independent, especially at steps, but they depend on the step orientation. In contrast, ΔGbari0 and ωij at terraces depend on the step density, following a linear tendency for terrace lengths larger than 5 atoms. However, while ΔGbari0 increases with the step density, ωij decreases. Results were explained by considering the modification in the energetic surface balance by hydrogen, Hads, and water, H2Oads, co-adsorption on the electrode, which in turn determines the whole adsorption processes on terraces and steps.

  2. Analysis of adsorption properties of typical partial discharge gases on Ni-SWCNTs using density functional theory

    Science.gov (United States)

    Zhang, Xiaoxing; Gui, Yingang; Xiao, Hanyan; Zhang, Ying

    2016-08-01

    To develop novel nanomaterial for online detection and diagnosis of insulated faults in SF6 insulated equipment, the nickel-doped single wall carbon nanotubes (Ni-SWCNTs) are proposed and its sensing capabilities for the measurement of typical decomposition products (SO2, SOF2 and SO2F2) of SF6 insulated gas are investigated in this work. The geometric configurations of decomposition products and (8, 0) zigzag Ni-SWCNTs, and adsorption properties are studied based on the first-principle density functional theory (DFT) methods implemented in the DMol3 package of Materials Studio. Three interaction models, single molecule, double identical molecules and double foreign molecules adsorption, have been studied to fully characterize the gas sensing mechanism under different situations. Simulation results reveal that Ni-SWCNTs have different sensitivity and selectivity to SO2 than SOF2 and SO2F2. The conductivity of Ni-SWCNTs increases in the following order: SO2 > SOF2 after SO2 and SOF2 adsorption. Conversely, the adsorption of SO2F2 onto Ni-SWCNTs slightly decreases its conductivity.

  3. Adsorption of cationic surfactants and their effects on the interfacial properties of quartz

    Science.gov (United States)

    Jia, Renhe

    This dissertation is primarily concerned with an investigation of the interfacial behavior of natural quartz in aqueous solution where the adsorption of various cationic surfactants is involved. The broad objective of this research was to delineate the mechanisms involved in the adsorption of cationic surfactants using experimental determination of adsorption isotherms, zeta potentials, suspension turbidity, contact angles, induction times, as well as Hallimond tube flotation response. With dodecylpyridinium chloride as the model surfactant, four-region adsorption isotherms were observed and found to correlate well with zeta potential, suspension stability and contact angle measurements. Calculations of adsorption energy showed strong specific adsorption in Region I, probably resulting from H-bonding of the pyridinium headgroup to active sites on the silica. As a result of hemimicelle formation at the solid-liquid interface in Region II, pronounced increases in the adsorption density, zeta potential, and surface hydrophobicity were observed. The stability of quartz suspensions showed a significant drop in this region. In Region III, the zeta potential is reversed and the stability of the suspensions begins to increase again. In this region, the surface hydrophobicity of quartz decreases with further surfactant adsorption, suggesting reverse orientation of the adsorbed surfactant ions. In Region IV, the adsorption isotherm and zeta potential reach a plateau when the surfactant concentration reaches the CMC, and the surface becomes completely hydrophilic. The molecular structure of surfactant ions (chain length, number of hydrocarbon chains and number of headgroups) was found to significantly affect their surface activity. Increasing the hydrocarbon chain length of the surfactant lowers the concentration of surfactant required for minimum suspension stability, as well as redispersion. The adsorption is stronger for surfactants whose structure permits hydrogen bonding

  4. Influence of sulfur coverage on the adsorption properties of S/Ir (001): a DFT study

    International Nuclear Information System (INIS)

    Using DFT calculations, we studied sulfur adsorbed on Ir (001) surface as a function of cover- age varying from 0.11 to 1.0 ML. Results shows that for lower coverages (θS≤ 0.50 ML) calculated adsorption energy is nearly unchanged, then it substantially decreases with the increasing coverage. Coverage-dependent modifications of surface d-band electronic structure upon S adsorption are discussed. (authors)

  5. Effects of pyrolysis temperature on soybean stover- and peanut shell-derived biochar properties and TCE adsorption in water.

    Science.gov (United States)

    Ahmad, Mahtab; Lee, Sang Soo; Dou, Xiaomin; Mohan, Dinesh; Sung, Jwa-Kyung; Yang, Jae E; Ok, Yong Sik

    2012-08-01

    Conversion of crop residues into biochars (BCs) via pyrolysis is beneficial to environment compared to their direct combustion in agricultural field. Biochars developed from soybean stover at 300 and 700 °C (S-BC300 and S-BC700, respectively) and peanut shells at 300 and 700 °C (P-BC300 and P-BC700, respectively) were used for the removal of trichloroethylene (TCE) from water. Batch adsorption experiments showed that the TCE adsorption was strongly dependent on the BCs properties. Linear relationships were obtained between sorption parameters (K(M) and S(M)) and molar elemental ratios as well as surface area of the BCs. The high adsorption capacity of BCs produced at 700 °C was attributed to their high aromaticity and low polarity. The efficacy of S-BC700 and P-BC700 for removing TCE from water was comparable to that of activated carbon (AC). Pyrolysis temperature influencing the BC properties was a critical factor to assess the removal efficiency of TCE from water. PMID:22721877

  6. Cheap adsorbent. Part 1: active cokes from lignites and improvement of their adsorptive properties by mild oxidation

    Energy Technology Data Exchange (ETDEWEB)

    Finqueneisel, G.; Zimny, T.; Albiniak, A.; Siemieniewska, T.; Vogt, D.; Weber, J.V. [Laboratoire de Chimie Industrielle, Saint-Avold (France)

    1998-05-01

    Cheap adsorbents were produced starting from two different lignites. About 500 kg of each coal was pyrolyzed in a rotary kiln at semi-pilot scale. Characterization of the obtained chars is made in terms of porosity development, surface functional groups and adsorptive properties determined for both 4-nitrophenol and lead. A post-oxidative treatment at low temperature is proposed in order to improve the adsorptive capacities of the initial chars by the introduction of oxygen containing functional groups, which are widely involved in chemisorption. The conditions of the post-treatment were chosen to be easily exported in an industrial process, for example during the cooling step. The importance of both lignite characteristics (ash content, water content) and pyrolysis conditions is demonstrated. The positive effect of a simple post-oxidative treatment is shown by a strong increase in the adsorptive capacities, and correlated to the evolution of the porosites and surface oxygen functionalities. Considering unit area, the properties of the active cokes are similar to those of commercial active carbon, but their specific areas are less developed (about 400 m{sup 2} g{sup -1}). 17 refs., 7 figs., 7 tabs.

  7. Adsorption Properties of Ni(II by D301R Anion Exchange Resin

    Directory of Open Access Journals (Sweden)

    Song Xiuling

    2014-01-01

    Full Text Available The adsorption of Ni(II with D301R resin was investigated in this paper. The results showed that the saturated extent of adsorption Ni(II by the resin was 84.3 mg/g. The equilibrium data of Ni(II sorption was better described by Langmuir isotherm model (r2=0.994 while that of Ni(II sorption also fitted in Freundlich isotherm model within the experimental concentration range. The amount of the constant (q0 of Ni(II under 298 K in Langmuir model was 76.92 mg/g, which was close to the experimental results. The constant n was within 2–10 in Freundlich model; it was shown that adsorption of Ni(II by the resin was easy to take place. The uptake kinetics followed the Lagergren pseudo-first-order rate equation (r2=0.9813. The particle diffusion controlled the adsorption process of Ni(II. The coefficient of the intraparticle diffusion increased with the increase of the pH values and the concentration of Ni(II in aqueous solution. There was a drop of 20.1 cm−1 for the bending vibration frequency of N–H bond. Results showed that the adsorption of Ni(II by D301R anion exchange resin was the surface complexation through the infrared spectrum analysis.

  8. Depth distribution of 137Cs adsorption property of clay minerals influenced by mineral weathering

    International Nuclear Information System (INIS)

    Radiocesium adsorption potential of mica clay mineral can increase as it is weathered, because K depletion in mica interlayer sites generates new Cs selective sites. However, in soils weathered under field conditions, the increase in 137Cs adsorption potential associated with mineral weathering has not been observed extensively. We investigated four soil profiles from Japan and Thailand with different soil pH ranges (3.3-4.0, 4.2-4.3, 5.0-5.7, and 5.5-7.3). The solid/liquid distribution coefficients of Cs (CsKd) in clay (137Cs adsorption potential of mica clay minerals. In three soil profiles, CsKd value in clay was the largest at a surface horizon and was decreased with depth, whereas in the most acidic of Podzolic soil profile, it was the largest at B horizon. The large CsKd value in surface clays relative to deeper horizons were well associated with that of 2.0-1.0 μm clay fraction. We assumed that the 137Cs adsorption potential increased at surface horizons mainly because coarser clay micas were weathered and generated Cs selective sites. The exceptional result obtained in Podzolic soil profile suggests that too intensive weathering destruct mica structure and may decrease in Cs adsorption potential of mica clay minerals. (author)

  9. The effect of polymer adsorption on the wetting properties of partially hydrophobized magnetite.

    Science.gov (United States)

    Potapova, E; Grahn, M; Holmgren, A; Hedlund, J

    2012-02-01

    Upon reverse flotation of iron ore, the surface of the iron ore concentrate may become partially hydrophobized due to adsorption of flotation collector, which is facilitated by the calcium ions present in the process water. Hydrophobic areas on the concentrate surface may introduce problems in subsequent pelletization of the concentrate. A possible way to restore the wettability of the surface could be by modifying the surface with a hydrophilic polymer. The effect of hydrophilic polymers of different types, viz. cationic, anionic, and non-ionic, on the wettability of the magnetite surface after adsorption of a surfactant was investigated. Although all the polymers could adsorb on magnetite at pH 8.5, the contact angle measurements revealed that only anionic ammonium polyacrylate could decrease the contact angle of synthetic magnetite after surfactant adsorption to a level close to that of as-synthesized magnetite. Such effect was probably achieved due to shielding of the hydrophobic surfactant chains from the aqueous phase by hydrophilic polyacrylate molecules. The fact that polyacrylate adsorption on magnetite occurred via calcium ions makes polyacrylate suitable for application in calcium-rich process water. The results presented in this work illustrate that ammonium polyacrylate could be successfully used to improve the wettability of magnetite after adsorption of surfactants. PMID:22047916

  10. Removal of aqueous uranyl ions by magnetic functionalized carboxymethylcellulose and adsorption property investigation

    International Nuclear Information System (INIS)

    Highlights: • The solvent in this synthetic is only water, it is very friendly to the environment. • Adsorbent with active surface rich in functional groups. • A magnetism is linked to this material and make it easy to separation. • Synthesis is in a facile pathway, the temperature are lower than 100 °C. • The maximum adsorption capacity toward uranium(VI) is 122.48 mg/g at 45 °C. - Abstract: Magnetic carboxymethylcellulose (CMC/Fe3O4) was used as a framework adsorption material to remove uranium ions from aqueous solutions. Carboxyl functional groups were grafted onto the CMC/Fe3O4. The maximum adsorption capacity of the magnetic composite toward U(VI) was 122.48 mg/g. Kinetic and thermodynamic parameters of the adsorption process were estimated. The pseudo-second-order model was more suitable and it proved to be an endothermic and spontaneous process. The Langmuir and Freundlich models were applied to evaluate the adsorption isotherm. The data matched well with Langmuir model after equilibrium was reached and with Freundlich model before equilibrium was reached

  11. Surface modification of glass beads with glutaraldehyde: Characterization and their adsorption property for metal ions

    International Nuclear Information System (INIS)

    In this study, a new material that adsorbs the metal ions was prepared by modification of the glass beads surfaces with glutaraldehyde. First, the glass beads were etched with 4 M NaOH solution. Then, they were reacted with 3-aminopropyl-triethoxysilane (APTES). Finally, silanized glass beads were treated with 25% of glutaraldehyde solution. The characterization studies by using Fourier Transform Infrared Spectroscopy (FT-IR), Thermal Gravimetric Analysis (TGA), elemental analysis and Scanning Electron Microscopy (SEM) indicated that modification of the glass bead surfaces was successfully performed. The adsorption studies exhibited that the modified glass beads could be efficiently used for the removal of the metal cations and anion (chromate ion) from aqueous solutions via chelation and ion-exchange mechanisms. For both Pb(II) and Cr(VI), selected as model ions, the adsorption equilibrium was achieved in 60 min and adsorption of both ions followed the second-order kinetic model. It was found that the sorption data was better represented by the Freundlich isotherm in comparison to the Langmuir and Redlich-Peterson isotherm models. The maximum adsorption capacities for Pb(II) and Cr(VI) were 9.947 and 11.571 mg/g, respectively. The regeneration studies also showed that modified glass beads could be re-used for the adsorption of Pb(II) and Cr(VI) from aqueous solutions over three cycles.

  12. 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.

  13. Synthesis and adsorption properties of chitosan-silica nanocomposite prepared by sol-gel method

    Science.gov (United States)

    Budnyak, Tetyana M.; Pylypchuk, Ievgen V.; Tertykh, Valentin A.; Yanovska, Elina S.; Kolodynska, Dorota

    2015-02-01

    A hybrid nanocomposite material has been obtained by in situ formation of an inorganic network in the presence of a preformed organic polymer. Chitosan biopolymer and tetraethoxysilane (TEOS), which is the most common silica precursor, were used for the sol-gel reaction. The obtained composite chitosan-silica material has been characterized by physicochemical methods such as differential thermal analyses (DTA); carbon, hydrogen, and nitrogen (CHN) elemental analysis; nitrogen adsorption/desorption isotherms, scanning electron microscopy (SEM); and Fourier transform infrared (FTIR) spectroscopy to determine possible interactions between silica and chitosan macromolecules. Adsorption of microquantities of V(V), Mo(VI), and Cr(VI) oxoanions from the aqueous solutions by the obtained composite has been studied in comparison with the chitosan beads, previously crosslinked with glutaraldehyde. The adsorption capacity and kinetic sorption characteristics of the composite material were estimated.

  14. Effect of the preparation conditions of Al-3%Y powder on its structural and adsorption properties

    Science.gov (United States)

    Ryabina, A. V.; Shevchenko, V. G.

    2016-01-01

    In view of the great practical utility of aluminum-rare earth metal (REM) powders as adsorbents and catalyst supports, the dispersion composition and morphology of Al-3%Y alloy powder particles obtained by various methods (gas plasma recondensation, nitrogen sputtering) were studied by low-temperature nitrogen adsorption, scanning electron microscopy, XRD, etc. The phase composition of the powders was determined, and the amount of active aluminum was calculated. The nitrogen adsorption on the powder surface was studied experimentally at-196°C at relative pressures of P/Ps = 10-3-0.999. The specific surface areas of the powders were determined.

  15. Adsorptive and electrical properties of InSb-ZnSe films

    International Nuclear Information System (INIS)

    An energy gap width and electric conductivity of InSb-ZnSe system specimens are determined. Using vacuum evaporation with subsequent vacuum heat treatment solid solutions of (InSb)x(ZnSe)1-x are synthesized and identified. Simultaneous measurements of CO adsorption and electric conductivity in solid solution and binary compound (InSb, ZnSe) films are made. In the pressure of CO the dependences of electric conductivity on temperature, pressure, time are analogous to those for adsorption and obey classic laws. Under adsorbate effect the electric conductivity of components of the system increases the more the higher the temperature and the initial pressure

  16. Photo- and thermochromic and adsorption properties of porous coordination polymers based on bipyridinium carboxylate ligands.

    Science.gov (United States)

    Toma, Oksana; Mercier, Nicolas; Allain, Magali; Kassiba, Abdel Adi; Bellat, Jean-Pierre; Weber, Guy; Bezverkhyy, Igor

    2015-09-21

    The zwitterionic bipyridinium carboxylate ligand 1-(4-carboxyphenyl)-4,4'-bipyridinium (hpc1) in the presence of 1,4-benzenedicarboxylate anions (BDC(2-)) and Zn(2+) ions affords three porous coordination polymers (PCPs): [Zn5(hpc1)2(BDC)4(HCO2)2]·2DMF·EtOH·H2O (1), [Zn3(hpc1)(BDC)2(HCO2)(OH)(H2O)]·DMF·EtOH·H2O (2), and [Zn10(hpc1)4(BDC)7(HCO2)2(OH)4(EtOH)2]·3DMF·3H2O (3), with the formate anions resulting from the in situ decomposition of dimethylformamide (DMF) solvent molecules. 1 and 3 are photo- and thermochromic, turning dark green as a result of the formation of bipyridinium radicals, as shown by electron paramagnetic resonance measurements. Particularly, crystals of 3 are very photosensitive, giving an eye-detectable color change upon exposure to the light of the microscope in air within 1-2 min. A very nice and interesting feature is the regular discoloration of crystals from the "edge" to the "core" upon exposition to O2 (reoxidation of organic radicals) due to the diffusion of O2 inside the pores, with this discoloration being slower in an oxygen-poor atmosphere. The formation of organic radicals is explained by an electron transfer from the oxygen atoms of the carboxylate groups to pyridinium cycles. In the structure of 3', [Zn10(hpc1)4(BDC)7(OH)6(H2O)2], resulting from the heating of sample 3 (desolvation and loss of CO molecules due to the decomposition of formate anions), no suitable donor-acceptor interaction is present, and as a consequence, this compound does not exhibit any chromic properties. The presence of permanent porosity in desolvated 1, 2, and 3' is confirmed by methanol adsorption at 25 °C with the adsorbed amount reaching 5 wt % for 1, 10 wt % for 3', and 13 wt % for 2. The incomplete desorption of methanol at 25 °C under vacuum points to strong host-guest interactions. PMID:26370743

  17. Effect of oxidation degree on the synthesis and adsorption property of magnetite/graphene nanocomposites

    Science.gov (United States)

    Luo, Kun; Mu, Yuanying; Wang, Peng; Liu, Xiaoteng

    2015-12-01

    A facile approach is demonstrated to synthesize a series of magnetite/graphene nanocomposites by solvothermal method, which can be easily collected after removal of pollutants without secondary pollution of graphene powders. Raman and FT-IR analyses show that the reduction of the mixing vapor of ammonia and hydrazine at different reaction periods generates the discrepancy of oxidation degree for reduced graphene oxide (rGO), which can be kept after the solvothermal synthesis of Fe3O4/rGO nanocomposites. Batch adsorption experiments indicate that the nanocomposite with maximum oxidation degree of rGO presents the largest magnetization of 35.4 emu g-1 and adsorption capacity of 59.2 mg g-1 for Cu2+, while the one with minimum oxidation degree exhibits the strongest adsorption of 39.0 mg g-1 for methylene blue accompanied with appropriate magnetization of 9.0 emu g-1, and only 23% of initial capacity was lost after seven recycling use. The adsorption kinetics of the both composites follows the pseudo-second-order model, suggestive of physical and chemical interactions between the pollutants and adsorbent. The results suggest that the oxidation degree of the rGO substrate can apparently influence both the structure and the adsorbing behavior of Fe3O4/rGO nanocomposites, which allows the control over the adsorbent performance according to the pollutant of interest.

  18. Fabrication of interfacial functionalized porous polymer monolith and its adsorption properties of copper ions

    Energy Technology Data Exchange (ETDEWEB)

    Han, Jiaxi; Du, Zhongjie; Zou, Wei; Li, Hangquan; Zhang, Chen, E-mail: zhangch@mail.buct.edu.cn

    2014-07-15

    Highlights: • Interface functionalized PGMA porous monolith was fabricated. • The adsorption capacity of Cu{sup 2+} was 35.3 mg/g. • The effects of porous structure on the adsorption of Cu{sup 2+} were studied. • The adsorption behaviors of porous monolith were studied. - Abstract: The interfacial functionalized poly (glycidyl methacrylate) (PGMA) porous monolith was fabricated and applied as a novel porous adsorbent for copper ions (Cu{sup 2+}). PGMA porous material with highly interconnected pore network was prepared by concentrated emulsion polymerization template. Then polyacrylic acid (PAA) was grafted onto the interface of the porous monolith by the reaction between the epoxy group on PGMA and a carboxyl group on PAA. Finally, the porous monolith was interfacial functionalized by rich amount of carboxyl groups and could adsorb copper ions effectively. The chemical structure and porous morphology of the porous monolith were measured by Fourier transform infrared spectroscopy and scanning electron microscopy. Moreover, the effects of pore size distribution, pH value, co-existing ions, contacting time, and initial concentrations of copper ions on the adsorption capacity of the porous adsorbents were studied.

  19. The Adsorption Properties of Bacillus atrophaeus Spores on Single-Wall Carbon Nanotubes

    Directory of Open Access Journals (Sweden)

    P. Cortes

    2009-01-01

    Full Text Available An adsorption equilibrium and a kinetic study of Bacillus atrophaeus on Single-Wall Carbon Nanotubes (SWCNTs were here performed to provide the basis for developing biosensor devices for detecting threatening micro-organisms in water supply systems. B. atrophaeus spores and carbon nanotubes were subjected to a batch adsorption process to document their equilibria and kinetics. Here, commercial nanotubes were either studied as received or were acid-purified before adsorption experiments. The Bacillus spores appear to show higher affinity towards the purified nanotubes than to the as-received nanomaterial. The effective diffusivity of the spores onto the purified nanotubes was found to be approximately 30 percent higher than onto the as-received nanotubes. It seems that the removal of amorphous carbon from the as-received nanotubes through a purification process yielded an intimate nantoubes-spore interaction as revealed by transmission electron microscopy. Freundlich model successfully correlated the adsorption equilibrium data for the nanotubes-spore interaction. Transmission electron micrographs showed extensive contact between the Bacillus and the purified nanotubes, but the association appeared less intimate between the spores and the as-received nanotubes.

  20. Effect of crosslinker on the swelling and adsorption properties of cationic superabsorbent

    Indian Academy of Sciences (India)

    TARUN SHARMA; GIRIDHAR MADRAS

    2016-06-01

    In the present study, superabsorbents (SAPs) of cationicmonomer [2-(methacryloyloxy) ethyl] trimethylammonium chloride have been prepared by free radical solution polymerization with different crosslinkers. They were subjected to repeated cycles of swelling and de-swelling in deionized water and NaCl solution. The conductivity of the swelling medium was measured and related to the swelling/de-swelling characteristics of the SAPs. The swelling capacity was also determined in saline solution. The swelling and de-swelling processes were described by first-order kinetics. The SAPs exhibited varied swelling capacity for crosslinkers of the same functionality as well as different functionality. The SAPs were used to adsorb the dye Orange G at different initial concentrations of the dye. The equilibrium adsorption data followed the Langmuir adsorption isotherms. The SAPs were also used to adsorb three other dyes, namely, Congo red, Amido black and Alizarin cyanine green. They exhibited different adsorption capacities for different dyes. The adsorption phenomenon was found to follow first-order kinetics.

  1. Ion Adsorption at the Rutile-Water Interface: Linking Molecular and Macroscopic Properties

    Czech Academy of Sciences Publication Activity Database

    Zhang, Z.; Fenter, P.; Cheng, L.; Sturchio, N. C.; Bedzyk, M. J.; Předota, Milan; Bandura, A.; Kubicki, J. D.; Lvov, S. N.; Cummings, P. T.; Chialvo, A. A.; Ridley, M. K.

    2004-01-01

    Roč. 20, č. 12 (2004), s. 4954-4969. ISSN 0743-7463 R&D Projects: GA ČR GP203/03/P083 Institutional research plan: CEZ:AV0Z4072921 Keywords : ion adsorption rutile Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 3.295, year: 2004

  2. Dye-adsorption capacity of bituminous fly ash and its pozzolanic property after used as dye-adsorbent

    Directory of Open Access Journals (Sweden)

    Penpolcharoen, M.

    2004-02-01

    Full Text Available Bituminous fly ash, which is an industrial waste, was used as an adsorbent to remove dyestuff from the textile-dye wastewater. The batch kinetic and isotherm experiments of the synthetic wastewater were firstly conducted to determine the adsorption behavior and optimal conditions for adsorption. The optimal conditions were then applied to the actual textile-dye wastewater. Under the original conditions of fly ash and wastewater, the results indicated that the color could be removed up to 86.65% by 12 g of the fly ash /L of the wastewater within 30 min. Its adsorption was described by the Freundlich isotherm. The dye-adsorbed fly ash was further studied on its pozzolanic property in terms of compressive strength by using it as a partial substitute to Portland cement type I to produce mortar. The result revealed that the highest compressive strength was of the sample containing 10% by weight of the dye-adsorbed fly ash in replacement of cement. It possessed 215 kg/cm2 at 28 days, which is 92.67% of the sample containing 10% by weight of the original fly ash in replacement of cement, or 83.33 of the cement mortar. For the environmental concern, leachabilities of lead (Pb, chromium (Cr, copper (Cu and zinc (Zn from all mortars were also carried out. No leaching of the heavy metals from any samples could be detected. Hence, the dye-adsorbed fly ash can be used as an environmental friendly construction material.

  3. SYNTHESES AND ADSORPTION PROPERTIES OF PHENOL-FORMALDEHYDE TYPE CHELATING RESINS BEARING THE FUNCTIONAL GROUP OF TARTARIC ACID

    Institute of Scientific and Technical Information of China (English)

    Rong-jun Qu; Chun-nuan Ji; Yan-zhi Sun; Zhong-fang Li; Guo-xiang Cheng; Ren-feng Song

    2004-01-01

    Several kinds of novel chelating resins bearing the functional group of tartaric acid (TTA-FQ-12, TTA-FQ-23, and TTA-FQ-34) were synthesized by reacting epoxy maleic anhydride, which was prepared through the oxidization reaction of maleic anhydride by hydrogen peroxide, with phenol-formaldehyde resin containing polyamine (FQ resins series). The effects of such factors as reaction time, reaction temperature and pH value on the loading capacity of TTA in resins were investigated. The results showed that the optimum reaction conditions are as follows: time 9-12 h; temperature 90-105℃;pH value 6-10. The loading capacities of TTA can reach 0.15, 0.14, and 0.11 mmol/g-1 when the functional group of FQ resin was -OCH2CH2NHC2H4NH2, -O(CH2CH2NH)2C2H4NH2 and -O(CH2CH2NH)3C2H4NH2), respectively. The structures of resins were characterized by FTIR spectra. The primary study on the adsorption properties of the resins for metal ions showed that there are two kinds of adsorption mechanisms i.e. ion exchange and chelate in the adsorption process.TTA-FQ resins have much higher adsorption selectivity for Pb2+and Zn2+ than for Cu2+ and Ni2+. These resins can probably be used for separating Pb2+ or Zn2+ in the mixture of metal ions or for treating wastewater containing heavy metal ions.

  4. Low-coverage adsorption properties of the metal-organic framework MIL-47 studied by pulse chromatography and Monte Carlo simulations.

    Science.gov (United States)

    Finsy, Vincent; Calero, Sofia; García-Pérez, Elena; Merkling, Patrick J; Vedts, Gill; De Vos, Dirk E; Baron, Gino V; Denayer, Joeri F M

    2009-05-14

    Low-coverage adsorption properties of the metal-organic framework MIL-47 were determined by a combined experimental and simulation study. Henry constants and low coverage adsorption enthalpies of C5-C8 linear and branched alkanes, cyclohexane and benzene were measured from 120 to 240 degrees C using pulse gas chromatography. An adapted force field for linear and branched alkanes in MIL-47 was used to compute the adsorption properties of those molecules. A new set of charges was developed for simulations with benzene in MIL-47. The adsorption enthalpy of linear alkanes increases with about 7.6 kJ mol(-1) per additional -CH2- group. Henry adsorption constants of iso-alkanes are slightly lower than those of the linear chains but the MIL-47 framework is not imposing steric constraints on the branched chains. Benzene and cyclohexane are adsorbed less strongly than n-hexane as they have less hydrogen atoms. For the studied non-polar molecules, the adsorption energies are dominated by van der Waals interactions and benzene adsorption is additionally influenced by Coulombic interactions. The simulated tendencies are in good agreement with the experiments. PMID:19421556

  5. Memory Effect of Mg―Al Hydrotalcites and Its Chromium(VI) Adsorption Property

    OpenAIRE

    ZHAO Ce, ZENG Hong-Yan, WANG Ya-Ju, LIU Ping-Le, LI Yu-Qin, YANG Yong-Jie

    2011-01-01

    Mg―Al hydrotalcite (MAH) with high crystallinity was prepared using urea method. The memory effect and the chromium(VI) adsorption property of Mg―Al Hydrotalcites were studied. The MAH, reconstructed MAH (RMAH), calcined MAH (MAO) and calcined RMAH (RMAO) were characterized by XRD, FT―IR, SEM and DSC as well as self―deconvolution analyses. The results showed that the MAH and RMAH possessed a layered structure of hyd...

  6. Thermodynamic Property Surfaces for Adsorption of R507A, R134a, and n -Butane on Pitch-Based Carbonaceous Porous Materials

    KAUST Repository

    Chakraborty, Anutosh

    2010-10-01

    The thermodynamic property surfaces of R507A, R134a, and n-butane on pitch-based carbonaceous porous material (Maxsorb III) are developed from rigorous classical thermodynamics and experimentally measured adsorption isotherm data. These property fields enable us to compute the entropy, enthalpy, internal energy, and heat of adsorption as a function of pressure, temperature, and the amount of adsorbate. The entropy and enthalpy maps are necessary for the analysis of adsorption cooling cycle and gas storage. We have shown here that it is possible to plot an adsorption cooling cycle on the temperature-entropy (T-s) and enthalpy-uptake (h-x) maps. Copyright © Taylor and Francis Group, LLC 2010.

  7. Impact of chabazite SSZ-13 textural properties and chemical composition on CO2 adsorption applications

    Energy Technology Data Exchange (ETDEWEB)

    Prodinger, Sebastian; Vemuri, Venkata Rama Ses; Varga, Tamas; McGrail, B. Peter; Motkuri, Radha K.; Derewinski, Miroslaw A.

    2016-04-01

    Chabazite SSZ-13 samples with varying silica content (Si/Al from 6 to 35) were synthesized in both stirring and static conditions to obtain material with changing particle size and morphology and thoroughly analysed with various characterization techniques. The role of particle size and chemical compositions of SSZ-13 chabazite on CO2 and N2 adsorption measurements was investigated. The Si/Al ratio played a major role for CO2 adsorption with Al-rich SSZ-13 showing a higher CO2 uptake than Al-poor material. This was attributed to the high density of active charged species in the chabazite cage. Particle size also played an important role in the sorption capacities with smaller particles, obtained in stirring conditions, showing enhanced CO2 uptakes compared to larger particles of same chemical composition. This was associated with an increased density of surface active sites and shorter diffusion pathways.

  8. Mg-MOF-74@SBA-15 hybrids: Synthesis, characterization, and adsorption properties

    International Nuclear Information System (INIS)

    Nanocrystals of Mg-MOF-74 have been immobilized into the mesopores of SBA-15 rods to fabricate Mg-MOF-74@SBA-15 hybrid materials. To furnish such composites, a relatively simple synthetic strategy has been adopted by direct dispersion of the metal-organic framework (MOF) precursors in SBA-15 matrix to prepare the hybrid materials in situ. The hybrid materials have been characterized using powder X-ray diffraction and several spectroscopic and microscopic techniques, which suggest growth of the MOF nanocrystals inside the SBA-15 mesopores and the composites exhibit characteristics of both the components. N2 adsorption isotherms at 77 K reveal that the composites contain additional mesopores, compared to only micropores of pristine MOF nanocrystals. In addition to such combination of both micro and mesoporosity, the composites also demonstrate significant CO2 adsorption at room temperature

  9. Mg-MOF-74@SBA-15 hybrids: Synthesis, characterization, and adsorption properties

    Directory of Open Access Journals (Sweden)

    Anindita Chakraborty

    2014-12-01

    Full Text Available Nanocrystals of Mg-MOF-74 have been immobilized into the mesopores of SBA-15 rods to fabricate Mg-MOF-74@SBA-15 hybrid materials. To furnish such composites, a relatively simple synthetic strategy has been adopted by direct dispersion of the metal-organic framework (MOF precursors in SBA-15 matrix to prepare the hybrid materials in situ. The hybrid materials have been characterized using powder X-ray diffraction and several spectroscopic and microscopic techniques, which suggest growth of the MOF nanocrystals inside the SBA-15 mesopores and the composites exhibit characteristics of both the components. N2 adsorption isotherms at 77 K reveal that the composites contain additional mesopores, compared to only micropores of pristine MOF nanocrystals. In addition to such combination of both micro and mesoporosity, the composites also demonstrate significant CO2 adsorption at room temperature.

  10. Mg-MOF-74@SBA-15 hybrids: Synthesis, characterization, and adsorption properties

    Energy Technology Data Exchange (ETDEWEB)

    Chakraborty, Anindita; Maji, Tapas Kumar, E-mail: tmaji@jncasr.ac.in [Molecular Materials Laboratory, Chemistry and Physics of Materials Unit, Jawaharlal Nehru Centre for Advanced Scientific Research, Jakkur, Bangalore 560064 (India)

    2014-12-01

    Nanocrystals of Mg-MOF-74 have been immobilized into the mesopores of SBA-15 rods to fabricate Mg-MOF-74@SBA-15 hybrid materials. To furnish such composites, a relatively simple synthetic strategy has been adopted by direct dispersion of the metal-organic framework (MOF) precursors in SBA-15 matrix to prepare the hybrid materials in situ. The hybrid materials have been characterized using powder X-ray diffraction and several spectroscopic and microscopic techniques, which suggest growth of the MOF nanocrystals inside the SBA-15 mesopores and the composites exhibit characteristics of both the components. N{sub 2} adsorption isotherms at 77 K reveal that the composites contain additional mesopores, compared to only micropores of pristine MOF nanocrystals. In addition to such combination of both micro and mesoporosity, the composites also demonstrate significant CO{sub 2} adsorption at room temperature.

  11. Adsorption properties and porous structure of sulfuric acid treated bentonites determined - SHORT COMMUNICATION

    Directory of Open Access Journals (Sweden)

    SNEZANA BREZOVSKA

    2005-02-01

    Full Text Available In a previous paper adsorption isotherms of benzene vapor on natural bentonite from Ginovci, Macedonia, and forms acid activated with 10 % and 15 % solutions of hydrochloric were interpreted by means of the Dubinin–Radushkevich–Stoeckli and Dubinin–Astakhov equations; the investigation has been continued with bentonites acid activated with 10 % and 15 % solutions of sulfuric acid where X-ray analysis indicates smaller structural changes. Using the above equations, the heterogeneity of the micropores and the energetic heterogeneity of the bentonites were determined from the differential distribution of the micropore volume with respect to the structural parameter of the equations characterizing the microporous structure and to the molar free energy of adsorption. Activated bentonites obtain bigger pores but also a certain quantity of new small pores appear during acid activation with the higher concentration of acid. The micropore volumes, determined from the adsorption of benzene vapor, of bentonites activated with 10 % and 15 % solution of hydrochloric acid (144.60 cm3 kg-1 and 110.06 cm3 kg-1, respectively, decrease in comparison with that of natural bentonite (162.55 cm3 kgv.1 In contrast, the values of the micropore volume for bentonities treated with 10 % and 15 % solutions of sulfuric acids increase (169.19 cm3 kg-1 and 227.74 cm3 kg-1. That is due to the difference in the structural changes occurring during activation with hydrochloric and sulfuric acids. The values of the free energy of adsorption of benzene vapor for natural bentonite are higher than those of the acid acitivated bentonities, what is in accordance with the structural and porosity changes.

  12. Adsorption properties and advanced textural characterization of novel micro/mesoporous zeolites

    Czech Academy of Sciences Publication Activity Database

    Rathouský, Jiří; Thommes, M.

    Amsterdam : Elsevier B.V./Ltd, 2007 - (Xu, R.; Gao, Z.; Chen, J.; Yan, W.), s. 1042-1047 ISBN 978-0-444-53068-4. - (Studies in surface science and catalysis. Vol. 170) R&D Projects: GA MŠk 1M0577 Institutional research plan: CEZ:AV0Z40400503 Keywords : micro/mesoporous zeolites * adsorption * textural characterization Subject RIV: CF - Physical ; Theoretical Chemistry

  13. The effect of doped Pd atoms on the geometries and optical adsorption properties of Au cluster: Au32−nPdn (n = 1, 2, 4 and 6)

    International Nuclear Information System (INIS)

    The geometries and optical adsorption properties of Au32−nPdn (n = 1, 2, 4, 6) alloy clusters were investigated within the static and time-dependent density functional theory. Our results confirm that Pd atoms favor to replace the inner Au atoms rather than the surface Au atoms of the cluster, which agrees well with previous reports. The optical adsorption property of the Au32 cluster is significantly changed by the Pd doping. Our calculations show that the optical adsorption of Pd-doped alloy cluster in the visible light region is remarkably enhanced compared to the pure Au32 cluster, especially in the lower energy sections. The analysis of the electronic structures of Au26Pd6, Au32 and Pd32 were performed to reveal the roles of doped Pd atoms. It is found that the doped Pd atoms increase the density of state around the Fermi level of the alloy clusters, which causes the enhanced optical adsorption of the Au–Pd alloy cluster in the visible light region. - Highlights: • The optical adsorption property of Au–Pd alloy cluster were investigated by TDDFT calculations. • Pd atoms favor the inner site in the Au–Pd alloy cluster. • The orbitals of Pd atoms substantively involve the states around the Fermi level of the alloy cluster. • Pd doping can enhance the optical adsorption of Au cluster under the visible light

  14. Synthesis, characterization, swelling and dye adsorption properties of starch incorporated acrylic gels.

    Science.gov (United States)

    Mandal, Bidyadhar; Ray, Samit Kumar

    2015-11-01

    Several hydrogels were prepared by a free radical polymerization of acrylic acid (AA), sodium acrylate (SA) and AA/hydroxy ethyl methacrylate (HEMA) in the presence of starch in water. These starch incorporated acrylic gels were prepared by varying the concentration of the initiator, monomer, crosslinker and the starch. The resulting gels were characterized by FTIR, SEM, XRD, DTA-TGA, pH at point zero charge (PZC), swelling and the diffusion in water. The gels showed high adsorption and removal% of Safranine T (ST) and Brilliant Cresyl Blue (BCB) dyes from water. The swelling and the adsorption data were fitted to different kinetic models and isotherms. Amongst the three kinds of gels, the starch incorporated sodium polyacrylate gel showed the highest adsorption of 9.7-85.3mg/L (97-61% removal) of BCB dye and 9.1-83mg/L (91-60% removal) of ST dye for a feed dye concentration of 10-140mg/L. PMID:26318665

  15. Structural, electronic and magnetic properties of linear monoatomic chains adsorption on beryllium oxide nanotube: First-principle study

    Energy Technology Data Exchange (ETDEWEB)

    Ma, Liang-Cai, E-mail: maliangcai@126.com [School of Physics and Electrical Information Engineering, Ningxia University, Yinchuan 750021, Ningxia (China); Zhao, Hong-Sheng; Yan, Wen-Jie [School of Physics and Electrical Information Engineering, Ningxia University, Yinchuan 750021, Ningxia (China)

    2013-03-15

    By using first-principle calculations, we have systematically investigated the structural, electronic and magnetic properties of six 3d transition metals (TM=Sc, Ti, V, Cr, Mn and Fe) linear monoatomic chains adsorbed on the (5,5) single-walled beryllium oxide nanotube (BeONT) at five different sites. The results indicate that all TM chains can be spontaneously adsorbed on the outer surface of the BeONT; and the O site is the most stable adsorption site for all TM chains with the highest binding energies, while the adsorption on the Z site is unstable. The dispersion character occurs in energy band curves of stable TM/BeONT systems and brings about the band gap disappearance in comparison with that of pure (5,5) BeONT. Interestingly, the Ti/BeONT and V/BeONT systems at O site show half-metal character; Cr at O site and Fe at O site as well as V at H site have high spin polarization P(E{sub F}) and these adsorbed systems are usable in spintronics devices. The TM chain adsorbed BeONT systems exhibit high stability, promising electronic properties and high magnetic moments, which may be useful for a wide variety of next-generation nanoelectronic device components. - Highlights: Black-Right-Pointing-Pointer All TM chains can be spontaneously adsorbed on the outer surface of BeONT. Black-Right-Pointing-Pointer O site is the most stable adsorption site with the highest binding energies. Black-Right-Pointing-Pointer Ti/BeONT and V/BeONT systems at O sites show half-metal character. Black-Right-Pointing-Pointer TM chain adsorbed BeONT systems exhibit high magnetic moments.

  16. Metal organic framework derived magnetically separable 3-dimensional hierarchical Ni@C nanocomposites: Synthesis and adsorption properties

    Science.gov (United States)

    Song, Yixuan; Qiang, Tingting; Ye, Ming; Ma, Qiuyang; Fang, Zhen

    2015-12-01

    Design an effective absorbent that has high surface area, and perfect recyclable is imperative for pollution elimination. Herein, we report a facile two-step strategy to fabricate magnetically separable 3-dimensional (3D) hierarchical carbon-coated nickel (Ni@C) nanocomposites by calcinating nickel based metal organic framework (Ni3(OH)2(C8H4O4)2(H2O)4). SEM and TEM images illuminate that the nanocomposites were constructed by 8 nm nickel nanoparticle encapsulated in 3D flake like carbon. The specific surface area of the obtained nanocomposites is up to 120.38 m2 g-1. Room temperature magnetic measurement indicates the nanocomposites show soft magnetism property, which endows the nanocomposites with an ideal fast magnetic separable property. The maximum adsorption capacity of the nanocomposites for rhodamine B is 84.5 mg g-1. Furthermore, the nanocomposites also exhibit a high adsorption capacity for heavy metal ions. The adsorbent can be very easily separated from the solution by using a common magnet without exterior energy. The as-prepared Ni@C nanocomposites can apply in waste water treatment on a large-scale as a new adsorbent with high efficiency and excellent recyclability.

  17. Study on adsorption and desorption properties of the starch grafted p-tert-butyl-calix[n]arene for butyl Rhodamine B solution

    International Nuclear Information System (INIS)

    The adsorbents of starch grafted p-tert-butyl-calix[4,6,8]arene-SGCn (SGC4, SGC6, SGC8) are prepared. The products are characterized by FTIR, elemental analysis, thermal gravimetric analysis and scanning electron microscope. Static adsorption behavior is studied by using SGC8 as adsorbent, butyl Rhodamine B (BRB) solution as simulation dye wastewater. The adsorption of BRB onto SGC8 fits the second order kinetic model and the apparent adsorption rate constant is 0.002 g mg-1 min-1 at 25 deg. C. The equilibrium adsorption data are interpreted using Langmuir and Freundlich models. The adsorption of BRB onto SGC8 is better represented by the Langmuir equation. The thermodynamic parameters for the adsorption reaction are calculated through van't Hoff analysis. The adsorbent may be easily regenerated by using ethanol solution as desorption agent to extract dye from SGC8. The rate of desorption of BRB is dependent on the concentration of ethanol and the temperature. SGC8 exhibits excellent adsorption and desorption properties toward dye molecule. The new-style adsorbent of SGC8 is regarded as a potential adsorbent to deal with dye or organic wastewater.

  18. Adsorption of Acetanilide Herbicides on Soil and Its Components: IV. Sorption of Acetanilide Herbicides on Soils and Its Correlation with Soil Properties

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    Sorption of acetanilide herbicides, metolachlor, acetochlor, pretilachlor and butachlor on eight soils with various physical and chemical properties was studied. The adsorption isotherms could fit Freundlich equation well (r2 >= 0.91) and the adsorption extents increased in the order: metolachlor < acetochlor < pretilachlor < butachlor. The product of Freundlich adsorption constants, Kf (1/n), showed to have a good correlation with organic matter content (OM) of soils for each of these herbicides, suggesting that OM is the primary factor dominating in the adsorption process of these acetanilide herbicides. Multivariant correlation regression between Kf(i/n) and two factors, water solubility (Sw) of herbicides and OM, was also performed. Kf(1/n) correlated with 1/Sw and OM/Sw well, showing that high Sw corresponds to a weak tendency to adsorb on soils. Infrared (IR) spectra and electron spin resonance (ESR) parameters confirmed that multifunctional H-bonds and charge-transfer bonds were the main adsorption mechanisms of these acetanilide herbicides. The abilities of herbicides to form these adsorption bonds with HA increased in the same order as the extent of adsorption.

  19. Effects of hydrogen adsorption on the properties of double wall BN and (BN)xCy nanotubes

    Science.gov (United States)

    Freitas, A.; Azevedo, S.; Kaschny, J. R.

    2016-01-01

    In the present contribution, we apply first-principles calculations, based on the density functional theory, to study the effects of hydrogen adsorption on the structural and electronic properties of boron nitride and hybrid carbon-boron nitride double wall nanotubes. The results demonstrate that the hydrogen decoration induces significant structural deformation and an appreciable reduction in the gap energy. When the number of hydrogen atoms introduced on the outer wall is increased, desorption of hydrogen pairs are observed. The calculations indicate that each adsorbed hydrogen atom induces a structural deformation with an energetic cost of about 68 meV/atom. It is also found that the introduction of hydrogen atoms can be applied as an efficient tool for tuning the electronic properties of such structures.

  20. Effect of organic matter properties, clay mineral type and thermal maturity on gas adsorption in organic-rich shale systems

    Science.gov (United States)

    Zhang, Tongwei; Ellis, Geoffrey S.; Ruppel, Stephen C.; Milliken, Kitty; Lewan, Mike; Sun, Xun

    2013-01-01

    A series of CH4 adsorption experiments on natural organic-rich shales, isolated kerogen, clay-rich rocks, and artificially matured Woodford Shale samples were conducted under dry conditions. Our results indicate that physisorption is a dominant process for CH4 sorption, both on organic-rich shales and clay minerals. The Brunauer–Emmett–Teller (BET) surface area of the investigated samples is linearly correlated with the CH4 sorption capacity in both organic-rich shales and clay-rich rocks. The presence of organic matter is a primary control on gas adsorption in shale-gas systems, and the gas-sorption capacity is determined by total organic carbon (TOC) content, organic-matter type, and thermal maturity. A large number of nanopores, in the 2–50 nm size range, were created during organic-matter thermal decomposition, and they significantly contributed to the surface area. Consequently, methane-sorption capacity increases with increasing thermal maturity due to the presence of nanopores produced during organic-matter decomposition. Furthermore, CH4 sorption on clay minerals is mainly controlled by the type of clay mineral present. In terms of relative CH4 sorption capacity: montmorillonite ≫ illite – smectite mixed layer > kaolinite > chlorite > illite. The effect of rock properties (organic matter content, type, maturity, and clay minerals) on CH4 adsorption can be quantified with the heat of adsorption and the standard entropy, which are determined from adsorption isotherms at different temperatures. For clay-mineral rich rocks, the heat of adsorption (q) ranges from 9.4 to 16.6 kJ/mol. These values are considerably smaller than those for CH4 adsorption on kerogen (21.9–28 kJ/mol) and organic-rich shales (15.1–18.4 kJ/mol). The standard entropy (Δs°) ranges from -64.8 to -79.5 J/mol/K for clay minerals, -68.1 to -111.3 J/mol/K for kerogen, and -76.0 to -84.6 J/mol/K for organic-rich shales. The affinity of CH4 molecules for sorption on organic matter

  1. Tuning the adsorption properties of isoreticular pyrazolate-based metal-organic frameworks through ligand modification.

    Science.gov (United States)

    Colombo, Valentina; Montoro, Carmen; Maspero, Angelo; Palmisano, Giovanni; Masciocchi, Norberto; Galli, Simona; Barea, Elisa; Navarro, Jorge A R

    2012-08-01

    Two isoreticular series of pyrazolate-based 3D open metal-organic frameworks, MBDP_X, adopting the NiBDP and ZnBDP structure types [H(2)BDP = 1,4-bis(1H-pyrazol-4-yl)benzene], were synthesized with the new tagged organic linkers H(2)BDP_X (X = -NO(2), -NH(2), -OH). All of the MBDP_X materials have been characterized through a combination of techniques. IR spectroscopy proved the effective presence of tags, while X-ray powder diffraction (XRPD) witnessed their isoreticular nature. Simultaneous TG/DSC analyses (STA) demonstrated their remarkable thermal stability, while variable-temperature XRPD experiments highlighted their high degree of flexibility related to guest-induced fit processes of the solvent molecules included in the channels. A structural isomer of the parent NiBDP was obtained with a sulfonate tagged ligand, H(2)BDP_SO(3)H. Structure solution from powder diffraction data collected at three different temperatures (room temperature, 90, and 250 °C) allowed the determination of its structure and the comprehension of its solvent-related flexible behavior. Finally, the potential application of the tagged MOFs in selective adsorption processes for gas separation and purification purposes was investigated by conventional single component adsorption isotherms, as well as by advanced experiments of pulse gas chromatography and breakthrough curve measurements. Noteworthy, the results show that functionalization does not improve the adsorption selectivity (partition coefficients) for the resolution of gas mixtures characterized by similar high quadrupole moments (e.g., CO(2)/C(2)H(2)); however, the resolution of gas mixtures containing molecules with highly differentiated polarities (i.e., N(2)/CO(2) or CH(4)/CO(2)) is highly improved. PMID:22765315

  2. CO2 adsorption properties of char produced from brown coal impregnated with alcohol amine solutions.

    Science.gov (United States)

    Baran, Paweł; Zarębska, Katarzyna; Czuma, Natalia

    2016-07-01

    Carbon dioxide (CO2) emission reduction is critical to mitigating climate change. Power plants for heating and industry are significant sources of CO2 emissions. There is a need for identifying and developing new, efficient methods to reduce CO2 emissions. One of the methods used is flue gas purification by CO2 capture through adsorption. This study aimed to develop CO2 adsorbent out of modified brown coal impregnated with solutions of first-, second-, and third-order amines. Low-temperature nitrogen adsorption isotherms and CO2 isotherms were measured for the prepared samples. The results of experiments unexpectedly revealed that CO2 sorption capacity decreased after impregnation. Due to lack of strait trends in CO2 sorption capacity decrease, the results were closely analyzed to find the reason for the inconsistencies. It was revealed that different amines represent different affinities for CO2 and that the size and structure of impregnating factor has influence on the CO2 sorption capacity of impregnated material. The character of a support was also noticeable as well for impregnation results as for the affinity to CO2. The influence of amine concentration used was investigated along with the comparison on how the theoretical percentage of the impregnation on the support influenced the results. The reaction mechanism of tertiary amine was taken into consideration in connection to no presence of water vapor during the experiments. Key findings were described in the work and provide a strong basis for further studies on CO2 adsorption on amine-impregnated support. PMID:27317051

  3. Inhibition properties and adsorption behavior of imidazole and 2-phenyl-2-imidazoline on AA5052 in 1.0 M HCl solution

    International Nuclear Information System (INIS)

    Highlights: • IM and 2-PI show corrosion inhibition for AA5052 in HCl solution. • Synergistic effect between IM and 2-PI is observed and its mechanism is assumed. • Adsorption properties are estimated using ΔGads0, ΔHads0 and Ea, respectively. • Adsorption structures and inhibition mechanism for AA5052 are proposed. - Abstract: The inhibition behavior of imidazole (IM) and 2-phenyl-2-imidazoline (2-PI) for AA5052 was investigated by weight loss, electrochemical, contact angle measurements and scanning electron microscopy. The results show that IM and 2-PI can inhibit the corrosion of AA5052 and the inhibition efficiency of 2-PI is higher. The adsorption properties of them are estimated using ΔGads0, ΔHads0 and Ea. The results reveal that the adsorption processes are exothermic reactions mainly by a monolayer chemisorption mechanism, and follow Langmuir adsorption isotherm. The differences of the monolayer adsorption structure between IM and 2-PI on AA5052 surface are analyzed, and the inhibition mechanisms are proposed

  4. Density Functional Theory Investigation of Adsorption Properties of CO, CO2 and H2O on γ-Al2O3 Supported Pt Clusters

    Science.gov (United States)

    Sensoy, Mehmet Gokhan; Ustunel, Hande; Toffoli, Daniele

    2014-03-01

    The water-gas shift reaction is a key catalytic process for the production of clean H2 gas for fuel cells.[2] In this study, we use plane wave pseudopotential density functional theory to study the adsorption properties and the activation of CO, CO2 and H2O on Pt clusters supported on the (001) surface of γ-Al2O3. A systematic study has been conducted to identify the most stable adsorption sites for both monoatomic and diatomic Pt clusters. Several stable adsorption geometries have been identified for the adsorbates, and their interaction with both the precious metal and the support is characterized in terms of adsorption energies and the nature of the bond between the adsorbed molecules and the precious metal. This work is supported by TUBITAK of Turkey (Grant No. 112T542), TR-GRID ULAKBIM and UHEM (Grant No. 1001942012).

  5. Effect of strong acids on red mud structural and fluoride adsorption properties.

    Science.gov (United States)

    Liang, Wentao; Couperthwaite, Sara J; Kaur, Gurkiran; Yan, Cheng; Johnstone, Dean W; Millar, Graeme J

    2014-06-01

    The removal of fluoride using red mud has been improved by acidifying red mud with hydrochloric, nitric and sulphuric acid. The acidification of red mud causes sodalite and cancrinite phases to dissociate, confirmed by the release of sodium and aluminium into solution as well as the disappearance of sodalite bands and peaks in infrared and X-ray diffraction data. The dissolution of these mineral phases increases the amount of available iron and aluminium oxide/hydroxide sites that are accessible for the adsorption of fluoride. However, concentrated acids have a negative effect on adsorption due to the dissolution of these iron and aluminium oxide/hydroxide sites. The removal of fluoride is dependent on the charge of iron and aluminium oxide/hydroxides on the surface of red mud. Acidifying red mud with hydrochloric, nitric and sulphuric acid resulted in surface sites of the form ≡SOH2(+) and ≡SOH. Optimum removal is obtained when the majority of surface sites are in the form ≡SOH2(+) as the substitution of a fluoride ion does not cause a significant increase in pH. This investigation shows the importance of having a low and consistent pH for the removal of fluoride from aqueous solutions using red mud. PMID:24703681

  6. The adsorption geometry and bonding properties of PTCDA on Ag(110)

    Energy Technology Data Exchange (ETDEWEB)

    Bauer, Oliver; Fiedler, Benjamin; Schmitz, Christoph H.; Sokolowski, Moritz [Institut fuer Physikalische und Theoretische Chemie, Universitaet Bonn (Germany); Mercurio, Giuseppe; Subach, Sergey; Tautz, Frank Stefan [Peter Gruenberg Institut (PGI-3), Forschungszentrum Juelich (Germany); JARA-Fundamentals of Future Information Technology (Germany)

    2011-07-01

    The vertical bonding distance of an adsorbate to the underlying surface can be regarded as a quantity related to the strength and the chemisorptive character of the bond. The Normal-Incidence X-ray Standing Wave (NIXSW) technique has recently been used to determine the bonding distance of perylene-3,4,9,10-tetracarboxylic acid dianhydride (PTCDA) on (111) coinage metal surfaces. In addition, we have investigated the adsorption geometry of PTCDA in the monolayer regime on the more open Ag(110) surface: We find a bonding distance of the perylene core to the substrate which is significantly smaller than the sum of the vdW radii of both Ag and C, indicating a strong chemical interaction. Furthermore, the PTCDA molecule adsorbs in an arc-like geometry with the O atoms being even closer to the surface than the perylene core. This hints at strong local, covalent Ag-O intercations. The experimental results are discussed in the framework of the Newns-Anderson model and the recent finding, that for coinage metal (111) surfaces the adsorption height of PTCDA correlates with the work function of the bare substrate.

  7. Analysis of adsorption layer on lubricating frictional surface by neutron reflectometry and its tribological properties

    International Nuclear Information System (INIS)

    Neutron reflectometry is able to observe directly a solid surface in lubricant. The principle, characteristics and the sample holder of neutron reflectometry are explained. Some experimental results are reported. Three diamond like carbon (DLC) films; the normal, hydrophilic and hydrophobic DLC, on silicon block in heavy water were observed by the neutron reflectometer (C3-1-2) at the JRR-3M reactor at JAEA. The results showed that the friction coefficient of hydrophilic DLC was the smallest value and that of hydrophobic DLC was the largest one. About 70 nm thick of iron film on silicon block under air, poly-alpha-olefin (PAO) and PAO plus additive were tested by MINE at JRR-3M. About 3 nm thickness of adsorption layers on the iron surface were observed. The friction coefficient of iron film under PAO was 0.1 and that under PAO plus additive was 0.07. This result showed that the adsorption layer with additive had a strong influence on the friction coefficient. Stribeck curve, the coherent scattering length, the optical system of MINE, the neutron reflectivity profile of nickel standard thin film on Si block, the reflectivity of hydrophilic DLC film/water, hydrophobic DLC film/water and iron film on Si block/lubricant, structure of sample holder, features of DLC film, and interface model of normal DLC film/water are illustrated. (S.Y.)

  8. Adsorption properties of carbonized polyacrylonitrile deposited on γ-alumina and silica gel by precipitation polymerization

    International Nuclear Information System (INIS)

    The precipitation polymerization method was used for the deposition of various contents of polyacrylonitrile on two oxide-type supports (γ-alumina and silica gel). The synthesized materials were characterized by thermal analysis performed in inert and oxidizing atmospheres. The mechanism of polyacrylonitrile decomposition was proposed. In order to gain effective adsorbents of volatile organic compounds the polyacrylonitrile/support composites were carbonized at elevated temperatures. The texture and morphology of the calcined materials were examined by low-temperature sorption of N2 and scanning electron microscopy, respectively. An influence of thermal treatment conditions and carbonaceous species loading on adsorption capacity of methyl-ethyl ketone vapour was also determined. Attenuated total reflection Fourier transform infrared spectroscopy measurements revealed that the ladder-type polyacrylonitrile species formed above 250 oC and stable up to about 350-400 oC are the most effective sites for methyl-ethyl ketone sorption. The carbonaceous species dispersion was found to be an additional factor influencing the adsorption capacity of the carbonized polyacrylonitrile/support composites.

  9. Adsorption of Microperoxidase-11 in Vertical Silica Mesochannels and Electrochemical Investigation of Its Electron Transfer Properties

    International Nuclear Information System (INIS)

    Highlights: • Vertical silica mesochannels (SMCs) were prepared on the indium tin oxide (ITO) electrode. • Microperoxidase-11 (MP-11) monomers were adsorbed to SMCs via electrostatic interaction. • The electron transfer reaction was studied by voltammetry. - Abstract: Microperoxidase-11 (MP-11) is an excellent model for hemoproteins such as cytochrome c. In this work, we report the adsorption of MP-11 onto silica mesochannels (SMCs) vertically attached to the indium tin oxide (ITO) electrode surface via the electrostatic attraction. Given the diameter of SMCs (2 ∼ 3 nm) is comparable to the molecular dimension of MP-11 (1.1 × 1.7 × 3.3 nm), only its monomeric form was selectively adsorbed by SMCs, as revealed by the UV-visible spectroscopy measurements. The cyclic voltammgram of adsorbed MP-11 molecules showed that the peak current was linearly dependent on the scan rate, suggesting the occurrence of a surface controlled process. And thus estimated surface coverage was indicative of adsorption of multiple MP-11 molecules in a SMC. We inferred that the electron transfer reaction is kinetically limited by the electron communication between MP-11 molecules adjacent to the electrode and the electrode. The rate constant was estimated to be 8.3 s−1

  10. Cationic cellulose nanofibers from waste pulp residues and their nitrate, fluoride, sulphate and phosphate adsorption properties.

    Science.gov (United States)

    Sehaqui, Houssine; Mautner, Andreas; Perez de Larraya, Uxua; Pfenninger, Numa; Tingaut, Philippe; Zimmermann, Tanja

    2016-01-01

    Cationic cellulose nanofibers (CNF) having 3 different contents of positively charged quaternary ammonium groups have been prepared from waste pulp residues according to a water-based modification method involving first the etherification of the pulp with glycidyltrimethylammonium chloride followed by mechanical disintegration. The cationic nanofibers obtained were observed by scanning electron microscopy and the extent of the reaction was evaluated by conductometric titration, ζ-potential measurements, and thermogravimetric analyses. The cationic CNF had a maximum cationic charge content of 1.2mmolg(-1) and positive ζ-potential at various pH values. Sorption of negatively charged contaminants (fluoride, nitrate, phosphate and sulphate ions) and their selectivity onto cationic CNF have been evaluated. Maximum sorption of ∼0.6mmolg(-1) of these ions by CNF was achieved and selectivity adsorption studies showed that cationic CNF are more selective toward multivalent ions (PO4(3-) and SO4(2-)) than monovalent ions (F(-) and NO3(-)). In addition, we demonstrated that cationic CNF can be manufactured into permeable membranes capable of dynamic nitrate adsorption by utilizing a simple paper-making process. PMID:26453885

  11. GIS-NaP1 zeolite microspheres as potential water adsorption material: Influence of initial silica concentration on adsorptive and physical/topological properties

    Science.gov (United States)

    Sharma, Pankaj; Song, Ju-Sub; Han, Moon Hee; Cho, Churl-Hee

    2016-03-01

    GIS-NaP1 zeolite samples were synthesized using seven different Si/Al ratios (5–11) of the hydrothermal reaction mixtures having chemical composition Al2O3:xSiO2:14Na2O:840H2O to study the impact of Si/Al molar ratio on the water vapour adsorption potential, phase purity, morphology and crystal size of as-synthesized GIS-NaP1 zeolite crystals. The X-ray diffraction (XRD) observations reveal that Si/Al ratio does not affect the phase purity of GIS-NaP1 zeolite samples as high purity GIS-NaP1 zeolite crystals were obtained from all Si/Al ratios. Contrary, Si/Al ratios have remarkable effect on the morphology, crystal size and porosity of GIS-NaP1 zeolite microspheres. Transmission electron microscopy (TEM) evaluations of individual GIS-NaP1 zeolite microsphere demonstrate the characteristic changes in the packaging/arrangement, shape and size of primary nano crystallites. Textural characterisation using water vapour adsorption/desorption, and nitrogen adsorption/desorption data of as-synthesized GIS-NaP1 zeolite predicts the existence of mix-pores i.e., microporous as well as mesoporous character. High water storage capacity 1727.5 cm3 g‑1 (138.9 wt.%) has been found for as-synthesized GIS-NaP1 zeolite microsphere samples during water vapour adsorption studies. Further, the total water adsorption capacity values for P6 (1299.4 mg g‑1) and P7 (1388.8 mg g‑1) samples reveal that these two particular samples can absorb even more water than their own weights.

  12. Synthesis, characterization and adsorption properties of magnetite/reduced graphene oxide nanocomposites.

    Science.gov (United States)

    Qi, Tingting; Huang, Chenchen; Yan, Shan; Li, Xiu-Juan; Pan, Si-Yi

    2015-11-01

    Three kinds of magnetite/reduced graphene oxide (MRGO) nanocomposites were prepared by solvothermal, hydrothermal and co-precipitation methods. The as-prepared nanocomposites were characterized and compared by Fourier transform infrared spectroscopy, scanning electron microscopy, transmission electron microscopy, X-ray diffraction and zeta potential. The results showed that MRGO made by different methods differed in surface functional groups, crystal structure, particle sizes, surface morphology and surface charge. Due to their unlike features, these nanocomposites displayed dissimilar performances when they were used to adsorb drugs, dyes and metal ions. The MRGO prepared by the co-precipitation method showed special adsorption ability to negative ions, but those synthesized by the solvothermal method obtained the best extraction ability and reusability to the others and showed a good prospective in magnetic solid-phase extraction. Therefore, it is highly recommended to use the right preparation method before application in order to attain the best extraction performance. PMID:26452936

  13. Incorporation of graphene nanosheets into cellulose aerogels: enhanced mechanical, thermal, and oil adsorption properties

    Science.gov (United States)

    Wan, Caichao; Li, Jian

    2016-02-01

    In this paper, novel graphene/cellulose (GC) aerogels were prepared based on a green NaOH/PEG solution. Scanning electron microscope observation indicates that the three-dimensional network skeleton structure of cellulose aerogels is tightly covered by the compact sheet structure. X-ray diffraction and Raman spectroscopy analyses demonstrate that the graphene nanosheets have been successfully synthesized and embedded in the cellulose aerogels. The incorporation of graphene nanosheets gives rise to the significant improvement in the specific surface area and pore volume, thermal stability, mechanical strength, and oil adsorption efficiency of GC aerogels. Therefore, the green hybrid GC aerogels have more advantages over the pure cellulose aerogels in treating oil-containing wastewater or oil spills under the harsh environment.

  14. Magnetic properties and adsorptive performance of manganese–zinc ferrites/activated carbon nanocomposites

    International Nuclear Information System (INIS)

    Owing to the unique microstructure and high specific surface area, activated carbon (AC) could act as an excellent adsorbent for wastewater treatment and good carrier for functional materials. In this paper, manganese–zinc ferrites (Mn0.5Zn0.5Fe2O4: MZF) were anchored into AC by hydrothermal method, resulting in the excellent magnetic response for AC nanocomposites in wastewater treatment. All results demonstrated the magnetic nanoparticles presented a spinel phase structure and existed in the pores of AC. The saturation magnetization (Ms) of MZF/AC nanocomposites increased with the ferrites content, while the pore volume and specific surface area declined. The Sample-5 possessed the specific surface area of 1129 m2 g−1 (close to 1243 m2 g−1 of AC) and Ms of 3.96 emu g−1. Furthermore, the adsorptive performance for organic dyes was studied and 99% methylene blue was adsorbed in 30 min. The magnetic AC nanocomposites could be separated easily from solution by magnetic separation technique. - Graphical abstract: The Sample-5 presented both good magnetic response and high BET surface area up to 1129 m2 g−1 (close to AC of 1243 m2 g−1), which could be separated completely for about 60 s. MZF/AC nanocomposites (Sample-3, 4, 5) in our work could be used as the magnetic absorbents, which could be separated easily by an outer magnet after the MB adsorption. - Highlights: • Mn0.5Zn0.5Fe2O4 (MZF) as few as possible was implanted into activated carbon (AC) for the higher surface area. • Sample-5 possessed the high specific surface area (1129 m2 g−1) and the suitable Ms (3.96 emu g−1). • Methylene blue was adsorbed almost completely by MZF/AC nanocomposites in 30 min. • MZF/AC nanocomposites were separated easily from solution by magnetic separation technique

  15. Characterization and determination of the thermodynamic and kinetic properties of the adsorption of molybdenum (VI) onto microcrystalline anthracene modified with 8-hydroxyquinoline

    International Nuclear Information System (INIS)

    A reliable and effective method for the determination of trace molybdenum in effluents is proposed. Molybdenum (VI) is analyzed by Microwave Plasma Torch Optical Emission Spectrometry (MPT-OES) based on the adsorption collection onto microcrystalline anthracene modified with 8-hydroxyquinoline. The possible reaction mechanism was discussed in detail and the optimum conditions for adsorption of Mo (VI) were confirmed. The experimental data were fitted well with the pseudo-second-order kinetic model and Langmuir model at all studied temperatures. The calculated thermodynamic parameters (ΔGT, ΔHT and ΔST) showed that the adsorption of molybdenum onto microcrystalline anthracene was feasible, spontaneous and endothermic at 280-320 K. The recovery of this method is in the range of 96.5%-103.3% with preconcentration factor of 100 and the limit detection after preconcentration is 0.078 μg L-1. The proposed method has been successfully applied to the determination of trace Mo (VI) in environmental water samples with satisfactory results. Highlights: → The preparation of the sorbent, MICRO-AN-8-hydroxyquinoline, is relatively simple. → Excellent properties of the sorbent have been illustrated in detail. → Exhaustive data concerning Mo(VI) adsorption behavior are provided. → Adsorption mechanism is firstly discussed from the view of ion-exchange reaction. → Offer reference for the studies on other metal ions adsorption onto the sorbent.

  16. Adsorption of Acetanilide Herbicides on Soil and Its COmponents: Ⅳ.Sorption of Acetanilide Herbicides on Soils and Its Correlation with Soil Properties

    Institute of Scientific and Technical Information of China (English)

    LIUWEIPING; WANGQIQUAN; 等

    2001-01-01

    Sorption of acetanilide herbicides,metolachlor,acetochlor,pretilachlor and butachlor on eight soils with various physical and chemical properties was studied,The adsporption isotherms could fit Freundlich equation well(r2≥0.91) and the adsorption extents increased in the order:metolachloradsorption constants,Kf(1/n),showed to have a good correlation with organic matter content(OM) of soils for each of these herbicides,suggesting that OM is the primary factor dominating in the adsorption process of these acetanilide herbicides.Multivariant orrelation regression between Kf(1/n) and two factors,water solubility(Sw) of herbicides and OM,was also performed,Kf(1/n) correlated with 1/Sw and OM/Sw well showing that high Sw corresponds to a weak tendency to adsorb on soils.Infrared(IR) spectra and electron pin resonance(ESR) parameters confirmed that multifunctional H-bonds and charge-transfer bonds were the mian adsorption mechanismes of these acetanilitde herbicides,The abilities of herbicides to form these adsorption bonds with HA increased in the same order as the extent of adsorption.

  17. Preparation, characterization and adsorption properties of chitosan modified magnetic graphitized multi-walled carbon nanotubes for highly effective removal of a carcinogenic dye from aqueous solution

    International Nuclear Information System (INIS)

    Novel chitosan-modified magnetic graphitized multi-walled carbon nanotubes (CS-m-GMCNTs) were synthesized via a suspension cross-linking method. Composition, morphology and magnetic properties of as-prepared CS-m-GMCNTs were characterized by XRD, SEM-EDS, BET and VSM. The large saturation magnetization (12.27 emu g−1) allows fast separation of CS-m-GMCNTs from treated aqueous solution. The adsorption of congo red (CR) on CS-m-GMCNTs was strongly dependent on pH, temperature of the aqueous phase and adsorbent dosage. Up to 100 and 94.58% color removal could be achieved in 100 min contact time with 10 and 50 mg L−1 of initial concentrations, respectively. The adsorption capacity of CR onto CS-m-GMCNTs could reach 262.9 mg g−1. The pseudo-second-order kinetic model with high correlation coefficients (R2 > 0.999) was suitable to describe the process of CR adsorption onto CS-m-GMCNTs. The Langmuir model fitted the adsorption isotherm data better than the Freundlich model. Values of thermodynamic parameters (ΔG°, ΔH° and ΔS°) indicated that the adsorption process was strongly dependent on temperature of the aqueous phase, and spontaneous and endothermic process in nature. Therefore, CS-m-GMCNTs adsorbent displays main advantages of excellent dispersion, convenience separation and high adsorption capacity, which implies their potential application in the environmental cleanup.

  18. Characterization and determination of the thermodynamic and kinetic properties of the adsorption of molybdenum (VI) onto microcrystalline anthracene modified with 8-hydroxyquinoline

    Energy Technology Data Exchange (ETDEWEB)

    Wang Xu [College of Chemistry and Environmental Science, Henan Normal University, Henan Key Laboratory for Environmental Pollution Control, Xinxiang, Henan 453007 (China); Zhang Yan [College of Chemistry and Chemical Engineering, Henan Institute of Science and Technology, Xinxiang, Henan 453003 (China); Li Quanmin, E-mail: mercury6068@hotmail.com [College of Chemistry and Environmental Science, Henan Normal University, Henan Key Laboratory for Environmental Pollution Control, Xinxiang, Henan 453007 (China)

    2011-12-01

    A reliable and effective method for the determination of trace molybdenum in effluents is proposed. Molybdenum (VI) is analyzed by Microwave Plasma Torch Optical Emission Spectrometry (MPT-OES) based on the adsorption collection onto microcrystalline anthracene modified with 8-hydroxyquinoline. The possible reaction mechanism was discussed in detail and the optimum conditions for adsorption of Mo (VI) were confirmed. The experimental data were fitted well with the pseudo-second-order kinetic model and Langmuir model at all studied temperatures. The calculated thermodynamic parameters ({Delta}G{sup T}, {Delta}H{sup T} and {Delta}S{sup T}) showed that the adsorption of molybdenum onto microcrystalline anthracene was feasible, spontaneous and endothermic at 280-320 K. The recovery of this method is in the range of 96.5%-103.3% with preconcentration factor of 100 and the limit detection after preconcentration is 0.078 {mu}g L{sup -1}. The proposed method has been successfully applied to the determination of trace Mo (VI) in environmental water samples with satisfactory results. Highlights: {yields} The preparation of the sorbent, MICRO-AN-8-hydroxyquinoline, is relatively simple. {yields} Excellent properties of the sorbent have been illustrated in detail. {yields} Exhaustive data concerning Mo(VI) adsorption behavior are provided. {yields} Adsorption mechanism is firstly discussed from the view of ion-exchange reaction. {yields} Offer reference for the studies on other metal ions adsorption onto the sorbent.

  19. A lead-porphyrin metal-organic framework: gas adsorption properties and electrocatalytic activity for water oxidation.

    Science.gov (United States)

    Dai, Fangna; Fan, Weidong; Bi, Jiahui; Jiang, Peng; Liu, Dandan; Zhang, Xirui; Lin, Huan; Gong, Chuanfang; Wang, Rongming; Zhang, Liangliang; Sun, Daofeng

    2016-01-01

    A 3D non-interpenetrating porous metal-organic framework [Pb2(H2TCPP)]·4DMF·H2O (Pb-TCPP) (H6TCPP = 5,10,15,20-tetra(carboxyphenyl)porphyrin) was synthesized by employment of a robust porphyrin ligand. Pb-TCPP exhibits a one-dimensional channel possessing fairly good capability of gas sorption for N2, H2, Ar, and CO2 gases, and also features selectivity for CO2 over CH4 at 298 K. Furthermore, Pb-TCPP shows electrocatalytic activity for water oxidation in alkaline solution. It is the first 3D porous Pb-MOF that exhibits both gas adsorption properties and electrocatalytic activity for an oxygen evolution reaction (OER). PMID:26606194

  20. Combined Neutron Diffraction and Adsorption Isotherm Study of the Anomalous Wetting Properties of NH3 on Graphite

    International Nuclear Information System (INIS)

    The wetting properties of NH3 films on graphite have been examined over a temperature range of approximately 50K (centered about the bulk triple point of 195.4K) using a combination of high-resolution vapor pressure isotherms and elastic neutron diffraction. Between 172 and 215K, a single adsorption step appears at reduced pressures above 0.5. As the system is cooled, the position of this step (which is shown to be associated with the formation of a thin liquid film) increases smoothly between 0.5 and 0.95. Evidence is put forward that there is a transition from complete wetting to incomplete wetting to nonwetting. Also, the role of cluster formation and hydrogen bonding is discussed. copyright 1997 The American Physical Society

  1. Effects of engineered nano-titanium dioxide on pore surface properties and phosphorus adsorption of sediment: Its environmental implications

    International Nuclear Information System (INIS)

    Highlights: → The attachment of Enano-TiO2 to surface enhanced markedly sediment BET surface area and t-Plot external surface area. → The fill of Enano-TiO2 into the micropores reduced significantly the sediment t-Plot micropore surface area. → Enano-TiO2 could increase sediment phosphorus (P) adsorption maximum and decrease in sediment P binding energy. → P would be easily released because of the decreasing P binding energy of the sediment with elevated Enano-TiO2. - Abstract: Understanding the environmental safety and human health implications of engineered nanoparticles (ENPs) is of worldwide importance. As an important ENPs, engineered nano-TiO2 (Enano-TiO2) may have been substantially deposited in aquatic sediments because of its widely uses. Sediment pore surface properties would be thus significantly influenced due to the large surface area of Enano-TiO2. In this study, Enano-TiO2 was found to greatly impact on sediment pore surface properties. The attachment of Enano-TiO2 particles to sediment surfaces enhanced markedly BET specific surface area and t-Plot external specific surface area, and thereby increased sediment phosphorus (P) adsorption maximum (Smax). Contrarily, the fill of Enano-TiO2 particles into the micropores of sediments could significantly reduce t-Plot micropore specific surface area, and cause slight decrease in sediment P binding energy (K). Clearly, P sorbed in sediment would be easily released because of the decreasing P binding energy of the sediment with elevated Enano-TiO2. Enano-TiO2 would thus cause aggravated endogenous pollution in water if such sediment was re-suspended on disturbance. The results obtained in this study contribute to our increasing knowledge of how to regulate physicochemical behavior of pollutants in sediments under the influences of Enano-TiO2 and/or similar ENPs.

  2. Syntheses, characterization and adsorption properties for Pb2+ of silica-gel functionalized by dendrimer-like polyamidoamine and 5-sulfosalicylic acid

    Science.gov (United States)

    Wu, Xiongzhi; Luo, Liangliang; Chen, Ziyan; Liang, Kailing

    2016-02-01

    Silica-gel adsorbents PAMAM-n.0SSASG (n = 1-4) with dendrimer-like polyamidoamine (PAMAM) and 5-sulfosalicylic acid as functional groups were prepared and characterized with FTIR, SEM, TG, elemental analysis and porous structure analysis. Micro-column enrichment and measurement of Pb2+ with graphite furnace atomic absorption spectroscopy (GFAAS) was studied with PAMAM-n.0SSASG (n = 1-4) as adsorbent. It was emphasized to investigate the relationship between dynamic adsorption/desorption rates, adsorption capacities, and grafting percentage of PAMAM onto silica-gel surface. Experiments showed that the generation increase of grafted PAMAM changed the pore diameter distribution of adsorbent and obviously improved adsorption/desorption property for Pb2+. Adsorption capacity of PAMAM-n.0SSASG (n = 1-4) was 14.04, 17.43, 20.07 and 25.05 mg g-1 for Pb2+ respectively. An enrichment factor of 200 was obtained with PAMAM-4.0SSASG as adsorbent and with 2000 mL Pb2+ solution (1.0 ng mL-1). The priority of adsorption property of PAMAM-4.0SSASG was explained by steric hindrance effect of PAMAM on adsorption/desorption, and selective adsorption of 5-sulfosalicylic acid with Pb2+. With PAMAM-4.0SSASG as adsorbent, GFAAS method for analysis of Pb2+ combined with micro-column enrichment was proposed and applied to the determination of Pb2+ of standard reference sample and sea water sample.

  3. Correlation between the Microstructure of Porous Materials and the Adsorption Properties of H2 and D2

    International Nuclear Information System (INIS)

    ligands, employed as linkers. The material properties can be optimized by changing these two main components. Owing to their high porosity, high storage capacity at low temperature, and excellent reversibility kinetics, MOFs have attracted a considerable attention as potential solid-state hydrogen storage materials. This novel class of porous adsorbents has been extensively investigated within this thesis. The greatest challenge for porous adsorbents is to increase the strength of the H2 binding interaction, and bring adsorption closer to RT conditions. Several strategies, aimed at improving hydrogen adsorption potential in MOFs are closely investigated. These strategies comprise the inclusion of open metal sites and the optimization of the pore size and, thus, the adsorption energy by ligand modification. The influence of the coordinatively unsaturated metal centers, liberated by the removal of metal-bound volatile species, has been particularly investigated. As for carbon materials, the H2-MOF interaction potential is especially enhanced in materials with the pore size comparable to the kinetic diameter of the hydrogen molecule. Such effects may result from the overlap of the potential field due to the proximity of the pore wall, which strengthen the interaction potential with the adsorbate molecule. However, smaller pores prevent hydrogen penetration and induce diffusion limitations. Furthermore, the molecular transport in confined pores at low temperatures may be significantly affected by quantum effects.

  4. A novel zinc(II) metal–organic framework with a diamond-like structure: synthesis, study of thermal robustness and gas adsorption properties

    Czech Academy of Sciences Publication Activity Database

    Almáši, M.; Zeleňák, V.; Zukal, Arnošt; Kuchár, J.; Čejka, Jiří

    2016-01-01

    Roč. 45, č. 3 (2016), s. 1233-1242. ISSN 1477-9226 R&D Projects: GA ČR GA14-07101S Institutional support: RVO:61388955 Keywords : synthesis * gas adsorption properties * physical chemistry Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 4.197, year: 2014

  5. Mesoporous zirconium titanium oxides. Part 2: Synthesis, porosity, and adsorption properties of beads.

    Science.gov (United States)

    Sizgek, G Devlet; Sizgek, Erden; Griffith, Christopher S; Luca, Vittorio

    2008-11-01

    Mesoporous zirconium titanium mixed-oxide beads having disordered wormhole textures and mole fractions of Zr (x) ranging from x=0.25 to 0.67 have been prepared. The bead preparation method combined the forced hydrolysis of mixtures of zirconium-titanium alkoxides in the presence of long-chain carboxylates with external gelation. Uniformly sized beads could be produced in the size range 0.5-1.1 mm by varying the droplet size and viscosity of the mixed-oxide sol, thus making them suitable for large-scale column chromatographic applications. The beads exhibited narrow pore size distributions with similar mean pore diameters of around 3.7 nm. The specific surface areas of the beads were linked to the Zr mole fraction in the precursor solution and were generally greater than 350 m2/g for x=0.5. A combination of scanning transmission electron microscopy and X-ray absorption fine structure analysis indicated that the pore walls of the beads were composed of atomically dispersed Zr and Ti to form a continuous network of Zr-O-Ti bonds. Mass transport in the beads was evaluated by monitoring the kinetics of vanadate and vanadyl adsorption at pH 10.5 and 0.87, respectively. PMID:18828618

  6. Response properties in the adsorption-desorption model on a triangular lattice

    Science.gov (United States)

    Šćepanović, J. R.; Stojiljković, D.; Jakšić, Z. M.; Budinski-Petković, Lj.; Vrhovac, S. B.

    2016-06-01

    The out-of-equilibrium dynamical processes during the reversible random sequential adsorption (RSA) of objects of various shapes on a two-dimensional triangular lattice are studied numerically by means of Monte Carlo simulations. We focused on the influence of the order of symmetry axis of the shape on the response of the reversible RSA model to sudden perturbations of the desorption probability Pd. We provide a detailed discussion of the significance of collective events for governing the time coverage behavior of shapes with different rotational symmetries. We calculate the two-time density-density correlation function C(t ,tw) for various waiting times tw and show that longer memory of the initial state persists for the more symmetrical shapes. Our model displays nonequilibrium dynamical effects such as aging. We find that the correlation function C(t ,tw) for all objects scales as a function of single variable ln(tw) / ln(t) . We also study the short-term memory effects in two-component mixtures of extended objects and give a detailed analysis of the contribution to the densification kinetics coming from each mixture component. We observe the weakening of correlation features for the deposition processes in multicomponent systems.

  7. Effect of the Chromium Ion Adsorption on the Photoluminescent Properties of Titanium Dioxide

    Directory of Open Access Journals (Sweden)

    V.V. Shimanovska

    2016-03-01

    Full Text Available We have studied the photoluminescence (PL of nanocrystalline titanium dioxide (TiO2, synthesized by the thermal hydrolysis in the form of anatase (A or rutile (R, the surface of which has been modified by adsorption of chromium ions (Cr3+. The samples were characterized by X-ray diffraction, X-ray fluorescence, Raman spectroscopy and optical absorption. PL spectra were excited by a nitrogen UV laser. It was found that the processes of the PL emission and optical absorption near the band gap edge of anatase and rutile TiO2 occur with the same electronic transitions. In the Cr3+-doped R/TiO2, the process of nonradiative Auger recombination leads to the quenching of the PL intensity. The Cr3+ ion doping in А/TiO2 leads to short-wave and long-wave shifts of the PL peaks due to the Burstein-Moss effect and due to the contribution of radiation "tails" of the electron density of states, respectively. PL intensity of the Cr3+-doped A/TiO2 at low concentration of Cr3+ (up to 0.5 at. % increases in comparison with the undoped A/TiO2 due to the formation of additional centers of radiative recombination of carriers. With increasing concentration of Cr3+ (~ 1.0 at. %, the TiO2 PL intensity decreases due to the concentration quenching.

  8. Effect of the Alkyl Chain Length on the Adsorption Properties of Malonamide Chelating Resins

    International Nuclear Information System (INIS)

    In order to investigate the effect of the alkyl chain length of malonamide chelating resins on the rate of uptake of U(VI) ions and Ce(III) Ions, lV,N,N',N'-tetraethyl malonamide (TEMA), N,N,N',N'-tetra-n-propyl malonamide (TPrMA), lV,lV,N',N'-tetra-n-butyl malonamide (TBMA) and N,l V,N',N'-tetra-n-pentyl malonamide (Tamp) chelating resins were synthesized by chemically bonding these function groups to CMS-DVB co-polymer beads. N,lV,N',N'-tetraphenyl malonamide (TPhMA) chelating resin was also investigated and the results of these resins were compared with those of N,lY,N',N-tetra methylmalonamide (TMMA) previously reported. The batch technique was used to study the thermodynamic equilibrium, in terms of distribution coefficient, and the kinetics of the adsorption U(VI) and Ce(III) ions from 3 M HNO3, Acid, and 3 M NaNO3 + 0.05 M HNO3, Salt, media. The introduction ratio of the function group into the polymer base and the uptake of U(VI) ions and C(III) ions were found to decrease with the increase in the alkyl chain length. The uptake was found to diminish in case of TPhMA resin due to the decrease of the function group ratio and the steric-hinder effect

  9. Effects of Mn, Cu doping concentration to the properties of magnetic nanoparticles and arsenic adsorption capacity in wastewater

    Energy Technology Data Exchange (ETDEWEB)

    Thi, Tran Minh, E-mail: tranminhthi@hnue.edu.vn; Trang, Nguyen Thi Huyen; Van Anh, Nguyen Thi

    2015-06-15

    Highlights: • Investigation the decrease of saturate magnetic moment of Fe{sub 3}O{sub 4} over time. • Substitution of Mn, Cu ions into Fe position to create stable properties of materials. • Investigate the surface and mesopore structure of nanoparticles. • The arsenic adsorption capacity of Cu doped Fe{sub 3}O{sub 4} nanomaterials is higher than of Fe{sub 3}O{sub 4} and Mn doped Fe{sub 3}O{sub 4} nanomaterials. - Abstract: The research results of Fe{sub 3}O{sub 4} and Mn, Cu doped Fe{sub 3}O{sub 4} nanomaterials synthesized by a chemical method for As(III) wastewater treatment are presented in this paper. The X-ray diffraction patterns and transmission electron microscopy images showed that samples had the cubic spinel structure with the grain sizes were varied from 9.4 nm to 18.1 nm. The results of vibrating sample magnetometer measurements at room temperature showed that saturation magnetic moments of Fe{sub 1−x}Cu{sub x}Fe{sub 2}O{sub 4} and Fe{sub 1−x}Mn{sub x}Fe{sub 2}O{sub 4} samples decreased from 65.9 emu/g to 53.2 emu/g and 65.9 emu/g to 61.5 emu/g, respectively, with the increase of Cu, Mn concentrations from 0.0 to 0.15. The nitrogen adsorption–desorption isotherm of a typical Fe{sub 3}O{sub 4} sample at 77 K was studied in order to investigate the surface and porous structure of nanoparticles by BET method. The specific surface area of Fe{sub 3}O{sub 4} magnetic nanoparticles was calculated about of 100.2 m{sup 2}/g. The pore size distribution of about 15–20 nm calculated by the BJH (Barrett, Joyner, and Halendar) method at a relative pressure P/P{sub 0} of about 1. Although the saturation magnetic moments of samples decreased when the increase of doping concentration, but the arsenic adsorption capacity of Cu doped Fe{sub 3}O{sub 4} nanoparticles is better than that of Fe{sub 3}O{sub 4} and Mn doped Fe{sub 3}O{sub 4} nanoparticles in a solution with pH = 7. In the solution with a pH > 14, the arsenic adsorption of magnetic

  10. Effects of Mn, Cu doping concentration to the properties of magnetic nanoparticles and arsenic adsorption capacity in wastewater

    International Nuclear Information System (INIS)

    Highlights: • Investigation the decrease of saturate magnetic moment of Fe3O4 over time. • Substitution of Mn, Cu ions into Fe position to create stable properties of materials. • Investigate the surface and mesopore structure of nanoparticles. • The arsenic adsorption capacity of Cu doped Fe3O4 nanomaterials is higher than of Fe3O4 and Mn doped Fe3O4 nanomaterials. - Abstract: The research results of Fe3O4 and Mn, Cu doped Fe3O4 nanomaterials synthesized by a chemical method for As(III) wastewater treatment are presented in this paper. The X-ray diffraction patterns and transmission electron microscopy images showed that samples had the cubic spinel structure with the grain sizes were varied from 9.4 nm to 18.1 nm. The results of vibrating sample magnetometer measurements at room temperature showed that saturation magnetic moments of Fe1−xCuxFe2O4 and Fe1−xMnxFe2O4 samples decreased from 65.9 emu/g to 53.2 emu/g and 65.9 emu/g to 61.5 emu/g, respectively, with the increase of Cu, Mn concentrations from 0.0 to 0.15. The nitrogen adsorption–desorption isotherm of a typical Fe3O4 sample at 77 K was studied in order to investigate the surface and porous structure of nanoparticles by BET method. The specific surface area of Fe3O4 magnetic nanoparticles was calculated about of 100.2 m2/g. The pore size distribution of about 15–20 nm calculated by the BJH (Barrett, Joyner, and Halendar) method at a relative pressure P/P0 of about 1. Although the saturation magnetic moments of samples decreased when the increase of doping concentration, but the arsenic adsorption capacity of Cu doped Fe3O4 nanoparticles is better than that of Fe3O4 and Mn doped Fe3O4 nanoparticles in a solution with pH = 7. In the solution with a pH > 14, the arsenic adsorption of magnetic nanoparticles is insignificant

  11. Applicability of carbon and boron nitride nanotubes as biosensors: Effect of biomolecular adsorption on the transport properties of carbon and boron nitride nanotubes

    Science.gov (United States)

    Zhong, Xiaoliang; Mukhopadhyay, Saikat; Gowtham, S.; Pandey, Ravindra; Karna, Shashi P.

    2013-04-01

    The effect of molecular adsorption on the transport properties of single walled carbon and boron nitride nanotubes (CNTs and BNNTs) is investigated using density functional theory and non-equilibrium Green's function methods. The calculated I-V characteristics predict noticeable changes in the conductivity of semiconducting BNNTs due to physisorption of nucleic acid base molecules. Specifically, guanine which binds to the side wall of BNNT significantly enhances its conductivity by introducing conduction channels near the Fermi energy of the bioconjugated system. For metallic CNTs, a large background current masks relatively small changes in current due to the biomolecular adsorption. The results therefore suggest the suitability of BNNTs for biosensing applications.

  12. Experimental study and computerized simulation of the elements fixation in trace on mineral oxides. Contribution to the study of natural solids adsorption properties

    International Nuclear Information System (INIS)

    The aim of this work is to identify some natural or synthetical materials allowing the nuclear wastes confinement in underground geological sites by adsorption of radioelements. The materials composition variety which can be used is very large it is then necessary to make use of models able to predict solid complexes behaviour towards the adsorption from known properties of parent constituents. This type of model still does not exist and its focusing requires the demonstration of mineral complexes parent constituents intrinsic properties additivity. The oxides as aluminium or silicon oxides being parent constituents, the author has demonstrated their properties additivity in an aluminium-silicon oxides physical mixture and in an aluminium silicate : the kaolinite. These surface properties have been determined for different quantities of aluminium and silicon oxides in a 0,1 M sodium nitrate. This study has been realized following the steps below : choice of a theoretical concept describing the adsorption adapted to the studied solid-solution system : the surface complexation model at constant capacitance; the focusing of a surface chemical and physical parameters determination method; the verification of these properties additivity on the aluminium-silicon oxides mixture and on the kaolinite. The studied cation for the adsorption on these materials is the ytterbium trivalent ion because the behaviour of the trivalent ions towards the adsorption is not very well known and because the lanthanides are considered as compounds similar to some fission products present in radioactive wastes. The method used for this work is applicable to all the other ions. (O.L.). 73 refs., 91 figs., 14 tabs

  13. Gas adsorption/separation properties of metal directed self-assembly of two coordination polymers with 5-nitroisophthalate

    International Nuclear Information System (INIS)

    Two new coordination polymers, namely, [Co(µ-nip)(µ-bpe)]n (1) and [Zn(µ-nip)(µ-bpe)]n (2) (nip: 5-nitroisophthalate, bpe: 1,2-bis(4-pyridyl)ethane) were hydrothermally synthesized and structurally characterized by single crystal X-ray diffraction, IR spectroscopy, elemental analysis and thermal analysis. Moreover, atomically detailed simulation studies of complex 2 for CO2/CH4 adsorption and separation were performed. Complex 1 consists of two dimensional (2D) (4,4) grid networks with the point symbol of 44.62. Complex 2 exhibits a 3-fold interpenetrating 3D framework with 65.8-dmp topology. Thermal properties of the complexes showed that both complexes were stable over 320 °C. Simulation studies demonstrated that complex 2 can separate CO2 from CH4 at low pressures at 273 K. - Graphical abstract: In this study, two new coordination polymers, namely, [Co(µ-nip)(µ-bpe)]n (1) and [Zn(µ-nip)(µ-bpe)]n (2) (nip: 5-nitroisophthalate, bpe: 1,2-bis(4-pyridyl)ethane) were hydrothermally synthesized and structurally characterized by single crystal X-ray diffraction, IR spectroscopy, elemental analysis and thermal analysis. Moreover, atomically detailed simulation studies of complex 2 for CO2/CH4 adsorption and separation were performed. Complex 1 consists of two dimensional (2D) (4,4) grid networks with the point symbol of 44.62. Complex 2 exhibits a 3-fold interpenetrating 3D framework with 65.8-dmp topology. Simulation studies demonstrated that complex 2 can separate CO2 from CH4 at low pressures at 273 K. Display Omitted - Highlights: • Two new coordination polymers with 5-nitroisophthalate and 1,2-bis(4-pyridyl)ethane. • Atomically detailed simulation studies of the complexes. • Complex 2 can be proposed as molecular sieve to separate CO2 from CH4 at low pressures

  14. Effect of Surface Chemistry and Physical Properties of Carbon Nanotubes on the Adsorption of Polycyclic Aromatic Hydrocarbons in Aqueous Solutions

    OpenAIRE

    Ramzan, Muhammad

    2013-01-01

    Adsorption behavior of seven different carbon nanotubes (CNTs) towards polycyclic aromatic hydrocarbons (PAHs) was studied in moderately hard reconstituted water (MHRW) with and without dissolved natural organic matter (NOM). At one concentration, adsorption of phenanthrene towards these CNTs was determined using negligible depletion solid phase micro extraction (nd-SPME) followed by GC-MS analysis. The single walled carbon nanotubes (SWCNTs) showed much higher adsorption than all other CNTs....

  15. Modification of the adsorption and catalytic properties of micro-and mesoporous materials by reactions with organometallic complexes

    Institute of Scientific and Technical Information of China (English)

    LEFEBVRE; Frédéric; PUTAJ; Piotr; BASSET; Jean-Marie

    2010-01-01

    This review describes the work of two laboratories in the field of the modification of micro-and mesoporous molecular sieves through reactions with organometallic complexes.The modification of zeolites can occur inside the pore channels or on the external surface,depending on the size of the organometallic complex.When the modification occurs on the external surface,it results in a decrease of the pore entrance,which will lead in turn to a modification of the sorption properties of the zeolite,by decreasing the rate of the adsorption(mainly by a kinetic control).Such a material can be also used in catalysis,because the external acid sites,which are responsible for side-reactions,have been removed upon grafting.When small organometallic complexes are used,they can fill the channels and cages of the zeolite and react with internal hydroxyl groups.Due to the high acidity of zeolites,the reaction occurs very easily(for example at-100℃ on faujasite),in contrast to what is observed on the external surface,therefore leading to high metal loadings.In that case,the modification of the sorption properties will be mainly related to a thermodynamic control.The resulting materials can be useful in catalysis,by combining the activity of the organometallic complex and properties(for example shape-selectivity) of the zeolite.Modification of mesoporous molecular sieves occurs always in the pores and results in altering of the sorption properties of the solid,by changing the interaction type between the sorbent and the sorbate.For example the sorption isotherm of alkanes is changed from type II to type III according to the IUPAC nomenclature.

  16. Temperature and magnetism bi-responsive molecularly imprinted polymers: Preparation, adsorption mechanism and properties as drug delivery system for sustained release of 5-fluorouracil.

    Science.gov (United States)

    Li, Longfei; Chen, Lin; Zhang, Huan; Yang, Yongzhen; Liu, Xuguang; Chen, Yongkang

    2016-04-01

    Temperature and magnetism bi-responsive molecularly imprinted polymers (TMMIPs) based on Fe3O4-encapsulating carbon nanospheres were prepared by free radical polymerization, and applied to selective adsorption and controlled release of 5-fluorouracil (5-FU) from an aqueous solution. Characterization results show that the as-synthesized TMMIPs have an average diameter of about 150nm with a typical core-shell structure, and the thickness of the coating layer is approximately 50nm. TMMIPs also displayed obvious magnetic properties and thermo-sensitivity. The adsorption results show that the prepared TMMIPs exhibit good adsorption capacity (up to 96.53mg/g at 25°C) and recognition towards 5-FU. The studies on 5-FU loading and release in vitro suggest that the release rate increases with increasing temperature. Meanwhile, adsorption mechanisms were explored by using a computational analysis to simulate the imprinted site towards 5-FU. The interaction energy between the imprinted site and 5-FU is -112.24kJ/mol, originating from a hydrogen bond, Van der Waals forces and a hydrophobic interaction between functional groups located on 5-FU and a NIPAM monomer. The electrostatic potential charges and population analysis results suggest that the imprinted site of 5-FU can be introduced on the surface of TMMIPs, confirming their selective adsorption behavior for 5-FU. PMID:26838836

  17. Strong basic anion exchangers with adsorption properties for chlorocomplex uranyl ion

    International Nuclear Information System (INIS)

    candidates for the adsorption of uranyl chlorocomplexes as it has been already demonstrated by the preliminary tests carried out comparative with some commercial anion exchange resins special synthesized for uranium isotope exchange. (authors)

  18. Thermoemission properties of lanthanum hexaboride in vacuum and at oxygen adsorption

    Energy Technology Data Exchange (ETDEWEB)

    Karetnikov, D.V.; Koryukin, V.A.; Obrezumov, V.P.

    1982-09-01

    Emission properties of lanthanum hexaboride were studied. Histograms of the distribution of work function on the surface were obtained under different temperature and time conditions. The effect of oxygen on work function and spectral degree of the sample blackness was studied. The authors determined dynamic characteristics of the interaction of oxygen with hot and cold surface.

  19. Thermoemission properties of lanthanum hexaboride in vacuum and at oxygen adsorption

    International Nuclear Information System (INIS)

    Emission properties of lanthan hexaboride were studied. Histograms of the distribution of work function on the surface were obtained under different temperature and time conditions. The effect of oxygen on work function and spectral degree of the sample blackness was studied. The authors determined dynamic characteristics of the interaction of oxygen with hot and cold surface

  20. Fluorinated graphenes as advanced biosensors - effect of fluorine coverage on electron transfer properties and adsorption of biomolecules

    Science.gov (United States)

    Urbanová, Veronika; Karlický, František; Matěj, Adam; Šembera, Filip; Janoušek, Zbyněk; Perman, Jason A.; Ranc, Václav; Čépe, Klára; Michl, Josef; Otyepka, Michal; Zbořil, Radek

    2016-06-01

    Graphene derivatives are promising materials for the electrochemical sensing of diverse biomolecules and development of new biosensors owing to their improved electron transfer kinetics compared to pristine graphene. Here, we report complex electrochemical behavior and electrocatalytic performance of variously fluorinated graphene derivatives prepared by reaction of graphene with a nitrogen-fluorine mixture at 2 bars pressure. The fluorine content was simply controlled by varying the reaction time and temperature. The studies revealed that electron transfer kinetics and electrocatalytic activity of CFx strongly depend on the degree of fluorination. The versatility of fluorinated graphene as a biosensor platform was demonstrated by cyclic voltammetry for different biomolecules essential in physiological processes, i.e. NADH, ascorbic acid and dopamine. Importantly, the highest electrochemical performance, even higher than pristine graphene, was obtained for fluorinated graphene with the lowest fluorine content (CF0.084) due to its high conductivity and enhanced adsorption properties combining π-π stacking interaction with graphene regions with hydrogen-bonding interaction with fluorine atoms.Graphene derivatives are promising materials for the electrochemical sensing of diverse biomolecules and development of new biosensors owing to their improved electron transfer kinetics compared to pristine graphene. Here, we report complex electrochemical behavior and electrocatalytic performance of variously fluorinated graphene derivatives prepared by reaction of graphene with a nitrogen-fluorine mixture at 2 bars pressure. The fluorine content was simply controlled by varying the reaction time and temperature. The studies revealed that electron transfer kinetics and electrocatalytic activity of CFx strongly depend on the degree of fluorination. The versatility of fluorinated graphene as a biosensor platform was demonstrated by cyclic voltammetry for different biomolecules

  1. Adsorption of polyhydroxyl based surfactants

    OpenAIRE

    Matsson, Maria

    2005-01-01

    Adsorption on solid surfaces from solution is a fundamental property of a surfactant. It might even be the most important aspect of surfactant behavior, since it influences many applications, such as cleaning, detergency, dispersion, separation, flotation, and lubrication. Consequently, fundamental investigations of surfactant adsorption are relevant to many areas. The main aim of this thesis has been to elucidate the adsorption properties, primarily on the solid/water interface, of a particu...

  2. Physicochemical properties and adsorption of cholesterol by okra (Abelmoschus esculentus) powder.

    Science.gov (United States)

    Chen, Yi; Zhang, Bing-Cheng; Sun, Yu-Han; Zhang, Jian-Guo; Sun, Han-Ju; Wei, Zhao-Jun

    2015-12-01

    Okra (Abelmoschus esculentus) is a widely used medicine and functional food. In order to clarify the effects of the particle size on its functional properties, okra pods were subjected to superfine grinding, and its properties were determined using different methods. Four particle size levels of okra powders were prepared: 380 to 250, 250 to 75, 75 to 40 and less than 40 μm. The results showed that superfine grinding technology could efficiently pulverize the particles into the submicron scale, whose distribution was close to a Gaussian distribution. With decreasing okra powder size, the specific surface area, water holding capacity (WHC), water-retention capacity (WRC), oil-binding capacity (OBC), tapped density and total flavonoids extraction were increased significantly (p grinding. These results suggest that okra powder can be used in food manufacturing as a functional food ingredient. PMID:26359588

  3. Adsorption Properties of Bentonite with In Situ Immobilized Polyaniline Towards Anionic Forms of Cr(VI, Mo(VI, W(VI, V(V

    Directory of Open Access Journals (Sweden)

    Kateryna RYABCHENKO

    2016-05-01

    Full Text Available A new composite material bentonite-PANI was synthesized by in situ immobilization of polyaniline (PANI on the surface of natural mineral bentonite. It was established as a result of the modification of bentonite a surface area and an interlayer distance of mineral decrease and particles of bentonite transformed of irregular shape with different porosity on irregularly shaped particles of smaller size. It has been found that the total Cr(VI ions extraction took place under the acid conditions (pH=1 – 2 and W(VI ions have been well adsorbed in the pH range from 1 to 8 by the composite bentonite-PANI unlike the initial mineral. Whereas adsorption of oxo anions of V(V and Mo(VI made up some 50%. It is proved that the in situ immobilization of bentonite by polyaniline leads to increasing the value of adsorption capacity towards the investigated ions compared with the initial mineral. It was established that the adsorption properties of the synthesized composite with respect to the studied oxo ions were worse than the adsorption properties of composite vermiculite-PANI, similar to the composite Sokyryntsyy clinoptilolite-PANI and better than composites of polyaniline with Podilskyy saponite and Karelian shungite.DOI: http://dx.doi.org/10.5755/j01.ms.22.2.6976

  4. The relationship between formate adsorption energy and electronic properties:A first principles density functional theory study

    Institute of Scientific and Technical Information of China (English)

    MA HongYan; WANG GuiChang; MORIKAWA Yoshitada; NAKAMURA Junji

    2009-01-01

    First principles density functional theory calculations have been performed for the chemisorption of formate adsorption on some metal surfaces.For the most stable adsorption site of short-bridge,the calculated formate adsorption energy follows the order of Au(110) < Ag(110) < Cu(110) < Pd(110) < Pt(110)< Ni(110)< Rh(110)< Fe(100)< Mo(100),and a clear linear correlation exists between the adsorption energy and the corresponding heat of formation of metal oxides.Moreover,it has been found that the formate adsorption energy for the transition metals can be correlated well with its d-band center (εd),and the IB Group metals can be described by the coupling matrix element square (Vad2).

  5. Adsorption properties of biomass-based activated carbon prepared with spent coffee grounds and pomelo skin by phosphoric acid activation

    Science.gov (United States)

    Ma, Xiaodong; Ouyang, Feng

    2013-03-01

    Activated carbon prepared from spent coffee grounds and pomelo skin by phosphoric acid activation had been employed as the adsorbent for ethylene and n-butane at room temperature. Prepared activated carbon was characterized by means of nitrogen adsorption-desorption, X-ray powder diffraction, scanning electron microscope and Fourier transform infrared spectroscope. It was confirmed that pore structure played an important role during the adsorption testes. Adsorption isotherms of ethylene and n-butane fitted well with Langmuir equation. The prepared samples owned better adsorption capacity for n-butane than commercial activated carbon. Isosteric heats of adsorptions at different coverage were calculated through Clausius-Clapeyron equation. Micropore filling effect was explained in a thermodynamic way.

  6. GIS-NaP1 zeolite microspheres as potential water adsorption material: Influence of initial silica concentration on adsorptive and physical/topological properties

    OpenAIRE

    Pankaj Sharma; Ju-Sub Song; Moon Hee Han; Churl-Hee Cho

    2016-01-01

    GIS-NaP1 zeolite samples were synthesized using seven different Si/Al ratios (5–11) of the hydrothermal reaction mixtures having chemical composition Al2O3:xSiO2:14Na2O:840H2O to study the impact of Si/Al molar ratio on the water vapour adsorption potential, phase purity, morphology and crystal size of as-synthesized GIS-NaP1 zeolite crystals. The X-ray diffraction (XRD) observations reveal that Si/Al ratio does not affect the phase purity of GIS-NaP1 zeolite samples as high purity GIS-NaP1 z...

  7. The effect of topological defects and oxygen adsorption on the electronic transport properties of single-walled carbon-nanotubes

    Energy Technology Data Exchange (ETDEWEB)

    Grujicic, M.; Cao, G.; Singh, R

    2003-04-30

    Ab initio density functional theory (DFT) calculations of the interactions between isolated infinitely-long semiconducting zig-zag (10, 0) or isolated infinitely-long metallic arm-chair (5, 5) single-walled carbon-nanotubes (SWCNTs) and single oxygen-molecules are carried out in order to determine the character of molecular-oxygen adsorption and its effect on electronic transport properties of these SWCNTs. A Green's function method combined with a nearest-neighbor tight-binding Hamiltonian in a non-orthogonal basis is used to compute the electrical conductance of SWCNTs and its dependence on the presence of topological defects in SWCNTs and of molecular-oxygen adsorbates. The computational results obtained show that in both semiconducting and metallic SWCNTs, oxygen-molecules are physisorbed to the defect-free nanotube walls, but when such walls contain topological defects, oxygen-molecules become strongly chemisorbed. In semiconducting (10, 0) SWCNTs, physisorbed O{sub 2}-molecules are found to significantly increase electrical conductance while the effect of 7-5-5-7 defects is practically annulled by chemisorbed O{sub 2}-molecules. In metallic (5, 5) SWCNTs, both O{sub 2} adsorbates and 7-5-5-7 defects are found to have a relatively small effect on electrical conductance of these nanotubes.

  8. Adsorption properties of gold(III), molybdenum(VI) and vanadium(V) on surface of green-teaparticles in aqueous solutions

    International Nuclear Information System (INIS)

    The adsorption properties of Au(III), Mo(VI) and V(V) ions on surface of the Japanese green-tea (powder tea) particles were examined by measurements of the adsorption percentage and by plotting the adsorption isotherm curves in aqueous solutions of pH 1∼6. The powder tea was treated with formaline in a dilute sulfuric acid. A 100 ml sample solution containing Au, Mo and/or V was mixed with the treated tea (0.1 or 0.5 g for usual use) under stirring for 30 min. The solution was then centrifuged and the concentrations of Au(III), Mo(VI) and V(V) ions in the supernatant solution were determined with the atomic absorption spectrometer. Au and Mo at pH 1∼6, and V at pH 3∼6 were adsorbed over 80% on the tea. The maximum adsorption amounts under the conditions were determined by the isotherm and Langmuir plots to be 23, 12 and 3.5 mg g-1 for Au, Mo and V, respectively. It was found that 50μg Au, 200μg Mo, and 150μg V in a 100 ml solution containing 10 or 30 g Zn(NO3)2·6H2O were quantitatively adsorbed on 0.1 g of the tea. Effect of NaCl, Na2SO4, Na2C2O4, 8-quinolinol, 1, 10-phenanthroline and EDTA (Na2[H2edta]) on the adsorbability of Au, Mo and V was examined. The adsorption percentage of Au did not change at all by addition of anyone of them. On the other hand, adsorption of Mo and V was seriously inhibited by addition of EDTA, and that of Mo was remarkably inhibited by addition of 1,10-phenanthroline. (author)

  9. A density functional study on properties of a Cu3Zn material and CO adsorption onto its surfaces

    Science.gov (United States)

    Tang, Qian-Lin; Duan, Xiao-Xuan; Liu, Bei; Wei, An-Qing; Liu, Sheng-Long; Wang, Qi; Liang, Yan-Ping; Ma, Xiao-Hua

    2016-02-01

    Prior experimental and theoretical efforts have provided strong evidence that the formation of α-brass such as Cu3Zn alloys in Cu/ZnO/Al2O3 CO2/CO hydrogenation catalysts enhances dramatically the catalytic activity toward methanol synthesis. In this work, a density functional theory (DFT) slab model has been adopted to get information concerning the bulk and surface properties of DO23-like Cu3Zn and to explore CO molecular adsorption, which will help pave the way to future rationalization of the impact of surface alloying on Cu/ZnO-based catalysis for CO2 and CO hydrogenations. Our calculations imply that the bulk modulus and cohesive energy of the binary solid solution lie between the corresponding ones for the individual components, but only the former quantity equals its composition weighted average. From the DFT-computed surface energies, the stability of Cu3Zn surfaces was predicted to be reinforced in the sequence (1 1 0) < (1 0 1) < (1 1 1) < (1 0 0) = (0 0 1) < (2 1 4) < (1 1 4), which can be interpreted as sensitive to the density change of surface dangling bonds. The downward shifts in the C-O stretch frequency measured experimentally over methanol synthesis catalysts at successively elevated reduction temperatures were correctly reproduced by the present simulation for the adsorption of CO to take place at Cu3Zn(1 1 4), Cu3Zn(2 1 4) and, as a reference, Cu(1 1 1). This agreement confirms the total energy results that indicate that the flat (1 1 4) and stepped (2 1 4) facets are the most stable and abundant ones in the Cu3Zn particles formed. It was found that a subtle compromise between the cost of fragment distortions and the large stabilization due to molecule-surface interaction is the way to control and optimize the reactivity of the Cu-based alloy to CO chemisorption. Intriguingly, electronic structure evaluation reveals that as far as all the alloy surfaces under scrutiny are concerned, a layer of CO brought a decrease, not an increase, in work

  10. Preparation, characterization and dye adsorption properties of γ-Fe2O3/SiO2/chitosan composite

    International Nuclear Information System (INIS)

    A γ-Fe2O3/SiO2/chitosan composite was prepared by water-in-oil emulsification, and characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM). Effects of various factors, including adsorbent dosage, initial dye concentration, solution pH, and competing anions, on the adsorption of methyl orange from aqueous solutions by the resulting composite were studied by batch adsorption experiments. The adsorption kinetics was found to follow the pseudo-second-order kinetic model, and intraparticle diffusion was related to the adsorption, but not as a sole rate-controlling step. The equilibrium adsorption data were well described by the Freundlich isotherm model. Evaluation of the thermodynamic parameters ΔG°, ΔH°, and ΔS° revealed that the adsorption process was naturally feasible, spontaneous, and exothermic. The composite was proven to be efficient, suitable and promising for the removal of methyl orange from aqueous solutions since it has a relatively higher adsorption capacity than other low-cost adsorbents.

  11. Adsorption properties and mechanism of U(Ⅵ) onto β-cyclodextrin cross-linked magnetic chitosan

    International Nuclear Information System (INIS)

    A β-cyclodextrin cross-linked magnetic chitosan, prepared by the method of graft copolymer, was used to adsorb U(Ⅵ) from aqueous solution. The effects of initial solution pH, adsorption time, temperature and other factors on U(Ⅵ) removal rate by p-cyclodextrin cross-linked magnetic chitosan were studied. The adsorption experimental results show that the adsorption equilibrium time of U(Ⅵ) onto β-cyclodextrin cross linked magnetic chitosan is 60 min, and low temperature and high adsorbent dosage are beneficial for the adsorption. The optimum pH for the adsorption ranges from 3.0 to 6.0. The desorption experimental results show that the U(Ⅵ) adsorption removal rate is reduced by only 7.41% after desorption of U(Ⅵ) in the β-cyclodextrin cross-linked magnetic chitosan for 5 times. SEM results show that the surface of β-cyclodextrin cross-linked magnetic chitosan is rough. Furthermore, the IR analysis shows that the -OH and -NH2 are the main binding sites on surface of β-cyclodextrin cross-linked magnetic chitosan, and its original structure has no significant change after adsorption of U(Ⅵ). (authors)

  12. Adsorption-Desorption of Hexaconazole in Soils with Respect to Soil Properties, Temperature, and pH

    Directory of Open Access Journals (Sweden)

    Maznah Zainol

    2016-07-01

    Full Text Available The effect of temperature and pH on adsorption-desorption of fungicide hexaconazole was studied in two Malaysian soil types; namely clay loam and sandy loam. The adsorption-desorption experiment was conducted using the batch equilibration technique and the residues of hexaconazole were analysed using the GC-ECD. The results showed that the adsorption-desorption isotherms of hexaconazole can be described with Freundlich equation. The Freundlich sorption coefficient (Kd values were positively correlated to the clay and organic matter content in the soils. Hexaconazole attained the equilibrium phase within 24 h in both soil types studied. The adsorption coefficient (Kd values obtained for clay loam soil and sandy loam soil were 2.54 mL/g and 2.27 mL/g, respectively, indicating that hexaconazole was weakly sorbed onto the soils due to the low organic content of the soils. Regarding thermodynamic parameters, the Gibb’s free energy change (ΔG analysis showed that hexaconazole adsorption onto soil was spontaneous and exothermic, plus it exhibited positive hysteresis. A strong correlation was observed between the adsorption of hexaconazole and pH of the soil solution. However, temperature was found to have no effect on the adsorption of hexaconazole onto the soils; for the range tested.

  13. Adsorption and Diffusion Properties of Ethylene, Benzene and Ethylbenzene in the Cylindrical Pore under Alkylation Reaction near Critical Regions by DCV-GCMD Simulation

    Institute of Scientific and Technical Information of China (English)

    刘涛; 刘洪来; 袁渭康

    2005-01-01

    A cylindrical pore model was used to represent approximately the pore of β-zeolite catalyst that had been used in the alkylation of benzene with ethylene and spherical Lennard-Jones molecules represented the components of the reaction system-ethylene, benzene and ethylbenzene. The dual control volume-grand canonical molecular dynamics (DCV-GCMD) method was used to simulate the adsorption and transport properties of three components under reaction in the cylindrical pore at 250℃ and 270℃ in the pressure range from 1 MPa to 8 MPa. The state map of the reactant mixture in the bulk phase could be divided into several different regions around its critical points. The simulated adsorption and transport properties in the pore were compared between the different near-critical regions. The thorough analysis suggested that the high pressure liquid region is the most suitable region for the alkylation reaction of benzene under the near-critical condition.

  14. Synthesis of aminated GMA-DVB copolymer and their adsorption properties for nitrate

    Energy Technology Data Exchange (ETDEWEB)

    Hwang, T.S.; Lee, S.A. [Chungnam National University, Taejeon (Korea); Lee, M.J. [Korea Atomic Energy Research Institute, Taejeon (Korea)

    2001-05-01

    In this study, we synthesized bead-type GMA-DVB copolymer using glycidylmethacrylate (GMA) with high reactivity and hydrophilicity. Macrorecticular anion exchanger containing the trimethylammonium group were then prepared by amination with trimethylammonium chloride. We observed that the size of NO{sub 3}{sup -} is smaller than that of SO{sub 4}{sup 2-} which disturb NO{sub 3}{sup -} removal in most of coexitent anions in ground water. Thus we investigated selective affinity for NO{sub 3}{sup -} and properties of individual ion exchangers with various DVB content. For each resins, we confirmed formation of copolymer by FT-IR spectrometer and investigated ion exchange capacity, swelling ratio, the amination yield and the effect with degree of crosslinking on adsorbability for nitrate. When amount of DVB is 4 wt%, amination yield, ion exchange capacity and swelling ratio was 384.3%, 3.25 meq/g and 77.1%, respectively. In these result, it can found that synthetic optimal condition is 4wt% DVB content for monomer. (author). 15 refs., 1 tab., 7 figs.

  15. Emission-adsorption properties of carbide and boride phase of coatings obtained by the method of direct electron-beam evaporation in the barium-containing flow

    International Nuclear Information System (INIS)

    Emission-adsorption properties of TiCsub(0.72), TiB2 and Nb2C coatings on molybdenum obtained by direct electron-beam evaporation are studied by the thermoemission method in the flow of the standard saturated aluminate cathode evaporation products. The Mo-electrode emission is suppressed most of all when applying the TiCsub(0.72) coating

  16. Magnetic adsorbent constructed from the loading of amino functionalized Fe3O4 on coordination complex modified polyoxometalates nanoparticle and its tetracycline adsorption removal property study

    Science.gov (United States)

    Ou, Jinzhao; Mei, Mingliang; Xu, Xinxin

    2016-06-01

    A magnetic polyoxometalates based adsorbent has been synthesized successfully through the loading of amino functionalized Fe3O4 (NH2-Fe3O4) on nanoparticle of a coordination complex modified polyoxometalates (CC/POMNP). FTIR illustrate there exist intense hydrogen bonds between NH2-Fe3O4 and CC/POMNP, which keep the stability of this adsorbent. At room temperature, this adsorbent exhibits ferromagnetic character with saturation magnetization of 8.19 emu g-1, which provides prerequisite for fast magnetic separation. Water treatment experiment illustrates this POM based magnetic adsorbent exhibits high adsorption capacity on tetracycline. The adsorption process can be described well with Temkin model, which illustrates the interaction between adsorbent and tetracycline plays the dominated role in tetracycline removal. The rapid, high efficient tetracycline adsorption ability suggests this POM based magnetic adsorbent exhibits promising prospect in medical and agriculture waste water purification. A magnetic polyoxometalates based adsorbent, which exhibits excellent tetracycline adsorption removal property has been synthesized through the loading of NH2-Fe3O4 on coordination complex modified polyoxometalates

  17. Adsorption properties and inhibition of mild steel corrosion in hydrochloric solution by some newly synthesized diamine derivatives: Experimental and theoretical investigations

    Energy Technology Data Exchange (ETDEWEB)

    Herrag, L.; Hammouti, B.; Elkadiri, S.; Aouniti, A. [Laboratoire de Chimie Appliquee et Environnement, LCAE-URAC18, Faculte des Sciences, Universite Mohammed Premier, B.P. 717, M-6000 Oujda (Morocco); Jama, C. [Unite Materiaux et Transformations (UMET), Ingenierie des Systemes Polymeres, CNRS UMR 8207, ENSCL, B.P. 90108, F-59652 Villeneuve d' Ascq Cedex (France); Vezin, H. [Laboratoire de Spectrochimie Infrarouge et Raman (LASIR), UMR-CNRS 8516, Universite des Sciences et Technologies de Lille, Batiment C5, F-59655 Villeneuve d' Ascq Cedex (France); Bentiss, F., E-mail: fbentiss@enscl.f [Laboratoire de Chimie de Coordination et d' Analytique (LCCA), Faculte des Sciences, Universite Chouaib Doukkali, B.P. 20, M-24000 El Jadida (Morocco)

    2010-09-15

    New diamine derivatives, namely 2-[{l_brace}2-[bis-(2-hydroxyethyl)amino]ethyl{r_brace}(2-hydroxyethyl)amino]ethanol (DAME) and 2-[{l_brace}2-[bis-(2-hydroxyethyl)amino]ethyl{r_brace}(2-hydroxyethyl)amino]propanol (DAMP) were synthesised and their inhibitive action against the corrosion of mild steel in 1 M HCl solution were investigated at 308 K. The detailed study of DAME is given using gravimetric measurements and polarization curves method. Results show that DAME is a good inhibitor and inhibition efficiency reaches 91.7% at 10{sup -3} M. Tafel polarization study revealed that DAME acts as a mixed-type inhibitor. The inhibitor adsorption process in mild steel/DAME/hydrochloric acid system was studied at different temperatures (308-353 K) by means of weight loss measurements. The adsorption of DAME on steel surface obeyed Langmuir's adsorption isotherm. The kinetic and thermodynamic parameters for mild steel corrosion and inhibitor adsorption, respectively, were determined and discussed. The comparative study of inhibitive performance of the two diamine derivatives revealed that DAME is more effective than DAMP. Quantitative Structure-Activity Relationship (QSAR) approach has been conducted in attempt to correlate the corrosion inhibition properties of these diamine derivatives with their calculated quantum chemical parameters.

  18. HYDROGEN ADSORPTION PROPERTIES OF METAL-ORGANIC FRAMEWORKS WITHIN THE DENSITY-FUNCTIONAL BASED TIGHT-BINDING APPROACH

    OpenAIRE

    BASSEM ASSFOUR; THAER ASSAAD; ADNAN ODEH

    2014-01-01

    Practical methods for hydrogen storage are still a prime challenge in the realization of an energy economy based on Hydrogen. Metal organic frameworks (MOFs) are crystalline ultra-porous materials with ability to trap and store voluminous amounts of gas molecules. MOFs represent an encouraging storage method relying on their enormous surface area. However, MOFs show reduced hydrogen uptake at room temperature due to low adsorption energy of hydrogen. To increase the adsorption uptake of MOFs ...

  19. Dye-adsorption capacity of bituminous fly ash and its pozzolanic property after used as dye-adsorbent

    OpenAIRE

    Penpolcharoen, M.

    2004-01-01

    Bituminous fly ash, which is an industrial waste, was used as an adsorbent to remove dyestuff from the textile-dye wastewater. The batch kinetic and isotherm experiments of the synthetic wastewater were firstly conducted to determine the adsorption behavior and optimal conditions for adsorption. The optimal conditions were then applied to the actual textile-dye wastewater. Under the original conditions of fly ash and wastewater, the results indicated that the color could be removed up to 86.6...

  20. Insight into the adsorption of PPCPs by porous adsorbents: Effect of the properties of adsorbents and adsorbates.

    Science.gov (United States)

    Zhu, Zengyin; Xie, Jiawen; Zhang, Mancheng; Zhou, Qing; Liu, Fuqiang

    2016-07-01

    Adsorption is an efficient method for removal of pharmaceuticals and personal care products (PPCPs). Magnetic resins are efficient adsorbents for water treatment and exhibit potential for PPCP removal. In this study, the magnetic hypercrosslinked resin Q100 was used for adsorption of PPCPs. The adsorption behavior of this resin was compared with those of two activated carbons, namely, Norit and F400D. Norit exhibited the fastest adsorption kinetics, followed by Q100. Norit featured a honeycomb shape and long-range ordered pore channels, which facilitated the diffusion of PPCPs. Moreover, the large average pore size of Q100 reduced diffusion resistance. The adsorbed amounts of 11 PPCPs on the three adsorbents increased with increasing adsorbate hydrophobicity. For Q100, a significant linear correlation was observed between the adsorption performance for PPCPs and hydrophobicity (logD value) of adsorbates (R(2) = 0.8951); as such, PPCPs with high logD values (>1.69) could be efficiently removed. Compared with those of Norit and F400D, the adsorption performance of Q100 was less affected by humic acid because of the dominant hydrophobic interaction. Furthermore, Q100 showed improved regeneration performance, which renders it promising for PPCP removal in practical applications. PMID:27131811

  1. Magnetic Zn (II) ion-imprinted polymer prepared by the surface imprinting technique and its adsorption properties.

    Science.gov (United States)

    Zhang, Hui-xin; Dou, Qian; Jin, Xiu-hong; Zhang, Jie; Yang, Ting-ru; Han, Xu; Wang, Dong-dong

    2015-01-01

    A novel magnetic Zn (II) ion-imprinted polymer was prepared by the surface ion-imprinted technique by using magnetic Fe3O4@SiO2 microspheres as supporter, methacrylic acid and salicylaldoxime as monomers, ethylene glycol dimethacrylate as the crosslinker. The products were characterized by Fourier transform infrared, X-ray photoelectron spectrometer, vibrating sample magnetometer and scanning electron microscope. The adsorption experiments showed that the imprinted polymer was employed successfully in comparison with non-imprinted polymer. When the temperature was in a range of 291-297 K, the maximum adsorption was about 52.69 mg g(-1) with an optimal pH 6.0 for an equilibrium time of 40 min. The imprinted polymer possessed high selectivity and specific recognition towards Zn (II). The Langmuir adsorption model was more favourable than the Freundlich or the Temkin adsorption model. Thermodynamic experiment showed that the adsorption was a spontaneous and endothermic process for Zn (II). The mechanism for Zn (II) adsorption on the imprinted polymer was investigated. PMID:25919981

  2. First principles investigations of the influence of O-adsorption on the structural and electronic properties of TiC(111) surfaces with vacancies

    Science.gov (United States)

    Ilyasov, Victor V.; Pham, Khang D.; Yalovega, Galina E.; Ershov, Igor V.; Ilyasov, Alexey V.; Nguyen, Chuong V.

    2016-07-01

    We used ab initio calculations to systematically investigate the adsorption of atomic oxygen on non-stoichiometric polar TiC(111) and Ti xC y(111) with Ti/C vacancies surface simulating its potential tructions with laser radiation. Local atomic structures of O/Ti xC y(111) polar surfaces were studied in the selected models as well as their thermodynamic and electronic properties based on the density functional theory. The bond length and adsorption energy for various reconstructions of the O/Ti xC y(111) surface atomic structure were established. We also have examined the effects of oxygen adsorption upon the band and electron spectra of TiC(111) surface in its various reconstructions. We have established a correlation between the energy level of flat bands (- 5.1 eV and - 5.7 eV) responsible for the doublet of singular peaks corresponding to partial densities of oxygen 2p electrons and the energy of oxygen adsorption in non-stoichiometric O/TiC y(111) systems. Effective charges of the oxygen atom and the titanium and carbon atoms nearest to it were identified in the examined adsorption models. We have established charge transfer from titanium atom to oxygen and carbon atoms determined by the reconstruction of local atomic and electronic structures. Charge transfer correlates with the electronegativity values of titanium, carbon, and oxygen atoms, and chemisorption processes. Calculated values of structural parameters in the studied models of ultrathin O/TiC(111) and O/Ti xC y(111) films correlate well with experimental findings and other theoretical results.

  3. Preparation of magnetic CoFe2O4-functionalized graphene sheets via a facile hydrothermal method and their adsorption properties

    International Nuclear Information System (INIS)

    Magnetic CoFe2O4-functionalized graphene sheets (CoFe2O4-FGS) nanocomposites have been synthesized by hydrothermal treatment of inorganic salts and thermal exfoliated graphene sheets. Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) observations show that cobalt ferrite nanoparticles with sizes of 10-40 nm are well dispersed on graphene sheets. OH- was recognized as a tie to integrate the inorganic salts with the graphene sheets, which made reaction started and developed on the surface of graphene sheets and formed cobalt ferrite nanoparticles on graphene sheets. The adsorption kinetics investigation revealed that the adsorption of methyl orange from aqueous solution over the as-prepared CoFe2O4-FGS nanocomposites followed pseudo-second-order kinetic model and the adsorption capacity was examined as high as 71.54 mg g-1. The combination of the superior adsorption of FGS and the magnetic properties of CoFe2O4 nanoparticles can be used as a powerful separation tool to deal with water pollution. -- Graphical abstract: OH- was recognized as a tie to integrate the inorganic salts with the graphene sheets, which made reaction started and developed on the surface of graphene sheets and formed cobalt ferrite nanoparticles on graphene sheets. Display Omitted Research highlights: → CoFe2O4-FGS have been prepared via a facile hydrothermal method. → CoFe2O4 nanoparticles with sizes of 10-40 nm are well dispersed on graphene sheets. → CoFe2O4-FGS with superior adsorption can be used for water treatment.

  4. Comparative study of adsorption properties of Turkish fly ashes II. The case of chromium (VI) and cadmium (II)

    Energy Technology Data Exchange (ETDEWEB)

    Bayat, Belgin

    2002-12-02

    The purpose of the study described in this paper was to compare the removal of Cr(VI) and Cd(II) from an aqueous solution using two different Turkish fly ashes; Afsin-Elbistan and Seyitomer as adsorbents. The influence of four parameters (contact time, solution pH, initial metal concentration in solution and ash quality) on the removal at 20{+-}2 deg. C was studied. Fly ashes were found to have a higher adsorption capacity for the adsorption of Cd(II) as compared to Cr(VI) and both Cr(VI) and Cd(II) required an equilibrium time of 2 h. The adsorption of Cr(VI) was higher at pH 4.0 for Afsin-Elbistan fly ash (25.46%) and pH 3.0 for Seyitomer fly ash (30.91%) while Cd(II) was adsorbed to a greater extent (98.43% for Afsin-Elbistan fly ash and 65.24% for Seyitomer fly ash) at pH 7.0. The adsorption of Cd(II) increased with an increase in the concentrations of these metals in solution while Cr(VI) adsorption decreased by both fly ashes. The lime (crystalline CaO) content in fly ash seemed to be a significant factor in influencing Cr(VI) and Cd(II) ions removal. The linear forms of the Langmuir and Freundlich equations were utilised for experiments with metal concentrations of 55{+-}2 mg/l for Cr(VI) and 6{+-}0.2 mg/l for Cd(II) as functions of solution pH (3.0-8.0). The adsorption of Cr(VI) on both fly ashes was not described by both the Langmuir and Freundlich isotherms while Cd(II) adsorption on both fly ashes satisfied only the Langmuir isotherm model. The adsorption capacities of both fly ashes were nearly three times less than that of activated carbon for the removal of Cr(VI) while Afsin-Elbistan fly ash with high-calcium content was as effective as activated carbon for the removal of Cd(II). Therefore, there are possibilities for use the adsorption of Cd(II) ions onto fly ash with high-calcium content in practical applications in Turkey.

  5. Nanohardness, corrosion and protein adsorption properties of CuAlO2 films deposited on 316L stainless steel for biomedical applications

    Science.gov (United States)

    Chang, Shih-Hang; Chen, Jian-Zhang; Hsiao, Sou-Hui; Lin, Guan-Wei

    2014-01-01

    This study preliminarily assesses the biomedical applications of CuAlO2 coatings according to nanoindentation, electrochemical, and protein adsorption tests. Nanoindentation results revealed that the surface hardness of 316L stainless steel increased markedly after coating with CuAlO2 films. Electrochemical tests of corrosion potential, breakdown potential, and corrosion current density showed that the corrosion resistance properties of 316L stainless steel are considerably improved by CuAlO2 coatings. Bicinchoninic acid (BCA) protein assay results revealed that the protein adsorption behavior of 316L stainless steel did not exhibit notable differences with or without CuAlO2 coatings. A CuAlO2 coating of 100 nm thickness improved the surface nanohardness and corrosion resistance ability of 316L stainless steel. CuAlO2 is a potential candidate for biomaterial coating applications, particularly for surface modification of fine, delicate implants.

  6. Characterization and ciprofloxacin adsorption properties of activated carbons prepared from biomass wastes by H3PO4 activation.

    Science.gov (United States)

    Sun, Yuanyuan; Li, Hong; Li, Guangci; Gao, Baoyu; Yue, Qinyan; Li, Xuebing

    2016-10-01

    As biomass wastes, Arundo donax Linn and pomelo peel were used as precursors for activated carbons (ALAC and PPAC) preparation by phosphoric acid activation. The pore structure and surface acidic functional groups of both carbons were characterized by nitrogen adsorption/desorption experiment, NH3-temperature-programmed desorption (NH3-TPD) and Fourier transform infrared spectroscopy (FTIR). A batch of experiments was carried out to investigate the adsorption performances of ciprofloxacin under different conditions. Results showed that PPAC exhibited larger surface area (1252m(2)/g) and larger portion of mesoporous, while ALAC was typical of microporous materials. Results from NH3-TPD suggested that ALAC was characteristic of more acidic functional group than PPAC. The maximum monolayer adsorption capability was 244mg/g for ALAC and 400mg/L for PPAC. Kinetics studies showed intra-particle diffusion was not the unique rate-controlling step. Boundary layer resistance existed between adsorbent and adsorbate. PMID:27034157

  7. A Three-Dimensional Dynamic Metal-Organic Framework with Fourfold Interpenetrating Diamondoid Networks and Selective Adsorption Properties.

    Science.gov (United States)

    Ju, Ping; Jiang, Long; Lu, Tong-Bu

    2015-07-01

    A three-dimensional metal-organic framework (1) with fourfold interpenetrating diamondoid networks was constructed using a macrocyclic nickel(II) complex and a tetracarboxylic ligand 4,4',4″,4‴-(cyclohexane-1,2-diyibis(azanetriyl))tetrakis(methylene)tetrabenzoic acid as building blocks. Despite the fourfold interpenetration, 1 possesses one-dimensional channels that are occupied by water and CH3CN guest molecules. Once the guest molecules were removed, the framework and pores in desolvated 1 are dynamic with large adsorption hysteresis loops, which exhibit selective gas adsorption for CO2 at 195 K over N2 and H2 at 77 K and selective adsorption for methanol, ethanol, and n-propanol over isopropanol at 298 K. PMID:26083145

  8. Effect of temperature and NO2 surface adsorption on electrical properties of screen printed ITO thin film

    Science.gov (United States)

    Madhi, I.; Meddeb, W.; Bouzid, B.; Saadoun, M.; Bessaïs, B.

    2015-11-01

    Indium tin oxide films with thicknesses of about 1 μm were prepared using the screen printing technique. Preliminary X-ray diffraction studies show that the formed ITO crystallizes in the cubic crystal system. The crystallite size (D) and the microstrain (ɛstr) were investigated using Scherrer formula and Williamson-Hall analysis. Scanning electron microscopy and transmission electron microscopy show that the ITO films are granular, essentially composed of uniformly distributed sub-spherical - like grains. The variation of the DC conductivity with temperature confirms the presence of three activation energies, indicating the presence of different scattering mechanisms essentially dominated by oxygen adsorption and thermal excitation of electrons in the conduction band. Detailed studies of the dielectric parameters (i.e., ɛ* and tan δ) of the compound as a function of temperature and NO2 adsorption (at various range of frequencies) reveal that their values are strongly dependent on temperature and NO2 adsorption.

  9. Adsorption Properties of Ionic Species on Cross-linked Chitosans Modified with Catechol and Salicylic Acid Moieties

    OpenAIRE

    Oshita, Koji; Takayanagi, Toshio; Oshima, Mitsuko; Motomizu, Shoji

    2008-01-01

    Catechol-type chitosan resin and salicylic acid-type chitosan resin were easily synthesized for use in estimating the adsorption behavior of 34 elements at pH 1 - 7 in aquatic media. The catechol-type chitosan resin could adsorb Cu(II) at pH 3 - 7, In(III) at pH 4 - 6, Pb(II) and lanthanoids at pH 5 - 7, and U(VI) at pH 4 - 7 more effectively than the salicylic acid-type chitosan resin and the cross-linked chitosan resin (base material). Adsorption ability was in the order: catechol-type chit...

  10. Preparation of polyacrylonitrile-potassium cobalt/titanium hexacyanoferrate (Ⅱ) spherical composite adsorbents and their adsorption properties for Cs+

    International Nuclear Information System (INIS)

    Polyacrylonitrile-potassium cobalt/titanium hexacyanoferrate (Ⅱ) spherical composite adsorbents (PAN-KCoCF and PAN-KTiCF) were prepared to remove cesium ions from aqueous solution. The effects of contact time, pH, competition ions and initial cesium concentration on cesium sorption were investigated via batch experiments. The adsorptive kinetics and isotherms were analyzed. The characterization of PAN-KCoCF and PAN-KTiCF were performed by SEM, FT-IR, XRD, etc. The results show that the cesium sorption of PAN-KCoCF and PAN-KTiCF can reach equilibrium after about 16 h. With the increase of pH, the cesium sorption of PAN-KTiCF increases fast at first and maintains at an almost constant value, while the cesium sorption of PAN-KCoCF isn't almost affected. Compared with PAN-KTiCF, the cesium sorption of PAN-KCoCF is more selective when K+, Na+, NH4+, Ca2+ or Mg2+ is added to solution. The sorption kinetics of two adsorbents for Cs+ can be described by pseudo second-order equation, and the sorption rate is mainly controlled by surface adsorption. The sorption of two adsorbents for cesium is monolayer adsorption, and the sorption data can be interpreted in terms of Langmuir isotherm. The saturated adsorption capacities of PAN-KCoCF and PAN-KTiCF are 128.370 mg/g and 278.552 mg/g, respectively. (authors)

  11. Adsorption of nitrate from aqueous solution by magnetic amine-crosslinked biopolymer based corn stalk and its chemical regeneration property.

    Science.gov (United States)

    Song, Wen; Gao, Baoyu; Xu, Xing; Wang, Fang; Xue, Nan; Sun, Shenglei; Song, Wuchang; Jia, Ruibao

    2016-03-01

    A novel adsorbent of magnetic amine-crosslinked biopolymer based corn stalk (MAB-CS) was synthesized and used for nitrate removal from aqueous solution. The characters and adsorption mechanisms of this bio-adsorbent were determined by using VSM, TGA, XRD, SEM, TEM, FT-IR and XPS, respectively. The results revealed that the saturated magnetization of MAB-CS reached 6.25 emu/g. Meanwhile, the studies of various factors indicated that this novel magnetic bio-adsorbent performed well over a considerable wide pH range of 6.0 ∼ 9.0, and the presence of PO4(3-) and SO4(2-) would markedly decrease the nitrate removal efficiency. Furthermore, the nitrate adsorption by MAB-CS perfectly fitted the Langmuir isotherm model (R(2)=0.997-0.999) and pseudo second order kinetic model (R(2)=0.953-0.995). The calculated nitrate adsorption capacity of MAB-CS was 102.04 mg/g at 318 K by Langmuir model, and thermodynamic study showed that nitrate adsorption is an spontaneous endothermic process. The regeneration experiments indicated its merit of regeneration and stability with the recovery efficient of 118 ∼ 147%. By integrating the experimental results, it was found that the removal of nitrate was mainly via electrostatic attraction and ion exchange. And this novel bio-adsorbent prepared in this work could achieve effective removal of nitrate and rapid separation from effluents simultaneously. PMID:26561752

  12. Inhibitive and Adsorption Properties of Ethanolic Extract of Allium Cepa for the Corrosion of -?Brass in HNO3 Solutions

    OpenAIRE

    Fouda, Abd El-Aziz S.; Nofal, Ashraf M.; Maher, Reham

    2015-01-01

    Ethanol extract of allium cepa has been evaluated as a green corrosion inhibitor for ?-brass in HNO3 solutions using weight loss, potentiodynamic polarization, electrochemical impedance spectroscopy (EIS) and electrochemical frequency modulation (EFM) techniques. Potentiodynamic polarization measurements showed that this extract acts as a mixed type inhibitor. The inhibition efficiency increases with increasing the extract concentration, but decreases with raising the temperature. The adsorpt...

  13. Thermogravimetric Study on Oxygen Adsorption/Desorption Properties of Double Perovskite Structure Oxides REBaCo2O5+δ (RE= Pr, Gd, Y)

    Institute of Scientific and Technical Information of China (English)

    Hao Haoshan; Zheng Lu; Wang Yingfang; Liu Shijiang; Hu Xing

    2007-01-01

    The oxygen adsorption/desorption properties of double perovskite structure oxides PrBaCo2O5+δ, GdBaCo2O5+δ, and YBaCo2O5+δ were investigated by the thermogravimetry (TG) method in the temperature range of 400~900 ℃. The calculated oxygen adsorption/desorption surface reaction rate constants ka and kd of these double perovskite structure oxides were larger than the commonly used cubic perovskite oxides, such as Ba0.95Ca0.05Co0.8Fe0.2O3-δ and Ba0.5Sr0.5Co0.8Fe0.2O3-δ, whereas, the oxygen permeation flux was comparable to that of the latter, which was attributed to the smaller difference of oxygen vacancy in oxygen and nitrogen atmosphere (Δδ/Vmol) in these double perovskite structure oxides. The large oxygen adsorption/desorption rate constants of GdBaCo2O5+δ and PrBaCo2O5+δ made them nice catalyst coating materials, on other membrane surfaces, to improve the oxygen permeability.

  14. Comparative studies on the adsorption properties of powdered activated carbon and propenoic acid modified sawdust in the treatment of secondary palm oil mill effluent

    International Nuclear Information System (INIS)

    Propenoic acid monomer was used to modify pulped cellulosic materials (sawdust). The sorption properties of the propenoic acid modified sawdust (PAMS) were compared with those of powdered activated carbon (PAC) in the tertiary treatment of palm oil mill effluent, previously clarified with iron (III) chloride plus lime (secondary effluent). The adsorption processes were effected in a fluidized bed reactor (FBR) at a pressure of 80 kilo Newton per meter square (kNm/sup -2/). Optimum amount of PAC and PAMS used for the fluidized adsorption of contaminants from the secondary palm oil mill effluent (POME) were 2.5 g/1 and 4.0 g/1, respectively. These sorption processes were found to be optimum at 10 min and 50 min for PAC and PAMS, respectively. At optimum sorption conditions, removal differentials of 28.6%/g chemical oxygen demand, 19.1%/g suspended solids, and 19.3%/g colour in favour of PAC were established. The application of optimum conditions for adsorption, for both adsorbents, to the bulk treatment of the palm oil mill effluent yielded a clear effluent with wider reuse applicability. (author)

  15. Adsorption characteristics, recognition properties, and preliminary application of nordihydroguaiaretic acid molecularly imprinted polymers prepared by sol-gel surface imprinting technology

    Science.gov (United States)

    Liao, Sen; Zhang, Wen; Long, Wei; Hou, Dan; Yang, Xuechun; Tan, Ni

    2016-02-01

    In this paper, a new core-shell composite of nordihydroguaiaretic acid (NDGA) molecularly imprinted polymers layer-coated silica gel (MIP@SiO2) was prepared through sol-gel technique and applied as a material for extraction of NDGA from Ephedra. It was synthesized using NDGA as the template molecule, γ-aminopropyltriethoxysilane (APTS) and methyltriethoxysilane (MTEOS) as the functional monomers, tetraethyl orthosilicate (TEOS) as the cross-linker and ethanol as the porogenic solvent in the surface of silica. The non-imprinted polymers layer-coated silica gel (NIP@SiO2) were prepared with the same procedure, but with the absence of template molecule. In addition, the optimum adsorption affinity occurred when the molar ratio of NDGA:APTS:MTEOS:TEOS was 1:6:2:80. The prepared MIP@SiO2 and NIP@SiO2 were analyzed by scanning electron microscopy (SEM), thermogravimetric analysis (TGA), and Fourier transform-infrared spectroscopy (FT-IR). Their affinity properties to NDGA were evaluated through dynamic adsorption, static adsorption, and selective recognition experiments, and the results showed the saturated adsorption capacity of MIP@SiO2 could reach to 5.90 mg g-1, which was two times more than that of NIP@SiO2. High performance liquid chromatography (HPLC) was used to evaluate the extraction of NDGA from the medicinal plant ephedra by the above prepared materials, and the results indicated that the MIP@SiO2 had potential application in separation of the natural active component NDGA from medicinal plants.

  16. Grafting of organosilane derived from 3-glycidoxypropyltrimethoxysilane and thiourea onto magnesium phyllosilicate by sol-gel process and investigation of metal adsorption properties

    International Nuclear Information System (INIS)

    A layered inorganic-organic magnesium silicate (Mg-GTPS-TU) has been successfully synthesized by using sol-gel based precursor under mild temperature conditions and a new silylaing agent (GTPS-TU) derived from 3-glycidoxypropyltrimethoxysilane (GTPS) and thiourea (TU) as the silicon source. The hybrid material was characterized through elemental analysis, infrared spectroscopy, X-ray diffractometry, thermogravimetry, and carbon and silicon solid-state nuclear magnetic resonance spectroscopy. The result confirmed the attachment of organic functionality to the inorganic silicon network. The inter-lamellar distance for the hybrid material was found to be 18.8 A. Metal adsorption characteristics follows Cr(III) >Mn(II)>Zn(II) with more affinity towards Cr(III) in dilute aqueous solution. Evaluation of thermodynamic parameters ΔH and ΔS for Cr(III) were found to be 25.44 J mol-1 and 79.9 J mol-1 K-1, respectively, indicating adsorption process to be endothermic in nature. The negative value of ΔG indicated the feasibility and spontaneity of ongoing adsorption process at relatively higher temperature. The presence of multiple coordination sites in the attached organic functionality expresses the potentiality of the hybrid material containing new silylating agent for heavy cation removal from eco-system. - Abstract: We report the synthesis and adsorption properties of a layered inorganic-organic magnesium silicate (Mg-GTPS-TU) derived from a new silylaing agent from 3-glycidoxypropyltrimethoxysilane (GTPS) and thiourea (TU) as the silicon source. Display Omitted

  17. CARBON DIOXIDE ADSORPTION PROPERTY OF ACTIVATED CARBON FROM BIOMASS%生物质活性炭吸附二氧化碳的性能研究

    Institute of Scientific and Technical Information of China (English)

    廖景明; 肖军; 沈来宏; 常连成

    2013-01-01

    利用农业废弃物玉米秆、麦壳和稻壳为原料,二氧化碳为活化剂一步法制备生物质活性炭,研究活性炭制备时间和活化剂浓度对二氧化碳吸附性能的影响.结果表明,玉米秆为原料制备的活性炭比稻壳和麦壳活性炭具有更发达的孔隙结构,二氧化碳吸附能力更强;该文获得的活性炭的最适宜制备条件为制备温度800℃,制备时间30min,活化剂浓度为20%;在二氧化碳吸附分压为10%时,吸附率达到1.86%,当分压增大到100%时,吸附率可达6.3%以上;且中孔孔容对二氧化碳吸附性能的影响作用明显.%Activated carbons were prepared from agricultural wastes (corn stalk, wheat hull and rice hull) with one-step process by utilizing carbon dioxide as activator. The effects of both preparation time and concentration of activator on the CO2 adsorption property of activated carbons were studied in this paper. The results show that the activated carbons prepared from corn stalks have more developed porous structure than those from wheat hulls and rice hulls and consequently have higher CO2 adsorption capacity. The suitable preparation condition of activated carbons for CO2 capture is at 800℃ with 20% CO2 flow for 30 minutes. The adsorption rate reaches to 1. 86% while CO2 partial pressure is 10%. When increasing the CO2 partial pressure from 10% to 100% , the adsorption rate could be more than 6.3%. Particularly, the CO2 adsorption property of activated carbons is affected obviously by meso-pore volume.

  18. Characterization of crude oil-water and solid -water interfaces and adsorption / desorption properties of crude oil fractions: The effect of low salinity water and pH

    Energy Technology Data Exchange (ETDEWEB)

    Farooq, Umer

    2010-09-15

    The reservoirs of conventional oil are rapidly depleting because of increased production and consumption of crude oil in the world. Mature and mostly depleted oil reservoirs require advanced recovery techniques to sustain the production rates. During the past years, a variety of enhanced oil recovery (EOR) methods have been developed and implemented to increase the oil recovery from mature reservoirs. Low Salinity Waterflooding (LSW) is an emerging EOR process of injecting water containing low concentrations (<4000 ppm) of total dissolved solids into the reservoir. This moderate cost process yields relatively higher incremental recoveries than other water based recovery methods. Investigation of mechanisms for increased recovery is quite challenging because this process depends upon complex crude oil/water/rock properties. This work was done to study the surface chemistry of typical reservoir surfaces where LSW can be used for EOR. The oil water and solid-water interfaces were characterised in low salinity aqueous solutions and investigated how the electrolytes and pH of solutions affect the interfacial and surface properties. The influence of low saline aqueous solution on the desorption behaviour of different fractions (acid-free oil and base-free oil) of crude oils was also explored. Reservoir minerals are sensitive to small changes in solution properties and therefore model, outcrop and reservoir particles were characterized in low salinity aqueous solutions. The extent of ionic adsorption on the mineral surfaces was found by various techniques. Particles were also characterized with respect to their elemental compositions. Asphaltene adsorption/desorption on reservoir rock surfaces play an important role in EOR processes. Various injection sequences of low saline aqueous solution of Na +, Ca2+ and sea water were considered to study the desorption of asphaltenes from silica surfaces. Composition of the aqueous phase influenced the interfacial properties of

  19. Preparation of a novel biosorbent ISCB and its adsorption and desorption properties of uranium ions in aqueous solution

    International Nuclear Information System (INIS)

    A novel biosorbent-immobilized Saccharomyces Cerevisiae beads (ISCB) was prepared by the sodium alginate-gelatin embedding method after dry cells had been cross-linked by formaldehyde. The kinetic model can be described by the pseudo-second-order model well, its correlation coefficient R 2 is 0.9952 ± 0.051; and the isotherm models is fitted to Langmuir adsorption model. The maximum uranium biosorption capacity was calculated to be (163.9 ± 12.2 mg g-1), indicating that ISCB is a good biosorbent. The uranium adsorption percent p is over 90 % after ISCB have been regenerated 8 times using EDTA and HNO3, implying that the ISCB has a good reusability. (author)

  20. Adsorption Properties of Low-Cost Biomaterial Derived from Prunus amygdalus L. for Dye Removal from Water

    Science.gov (United States)

    Deniz, Fatih

    2013-01-01

    The capability of Prunus amygdalus L. (almond) shell for dye removal from aqueous solutions was investigated and methyl orange was used as a model compound. The effects of operational parameters including pH, ionic strength, adsorbent concentration and mesh size, dye concentration, contact time, and temperature on the removal of dye were evaluated. The adsorption kinetics conformed to the pseudo-second-order kinetic model. The equilibrium data pointed out excellent fit to the Langmuir isotherm model with maximum monolayer adsorption capacity of 41.34 mg g−1 at 293 K. Thermodynamic analysis proved a spontaneous, favorable, and exothermic process. It can be concluded that almond shell might be a potential low-cost adsorbent for methyl orange removal from aqueous media. PMID:23935442

  1. Synthesis and Adsorption Property of SiO2@Co(OH2 Core-Shell Nanoparticles

    Directory of Open Access Journals (Sweden)

    Yongde Meng

    2015-04-01

    Full Text Available Silica nanoparticles were directly coated with cobalt hydroxide by homogeneous precipitation of slowly decomposing urea in cobalt nitrate solution. The cobalt hydroxide was amorphous, and its morphology was nanoflower-like. The BET (Brunauer-Emmett-Teller surface area of the core-shell composite was 221 m2/g. Moreover, the possible formation procedure is proposed: the electropositive cobalt ions were first adsorbed on the electronegative silica nanoparticles surface, which hydrolyzed to form cobalt hydroxide nanoparticles. Then, the cobalt hydroxide nanoparticles were aggregated to form nanoflakes. Finally, the nanoflakes self-assembled, forming cobalt hydroxide nanoflowers. Adsorption measurement showed that the core-shell composite exhibited excellent adsorption capability of Rhodamine B (RB.

  2. Adsorption Properties of Low-Cost Biomaterial Derived from Prunus amygdalus L. for Dye Removal from Water

    Directory of Open Access Journals (Sweden)

    Fatih Deniz

    2013-01-01

    Full Text Available The capability of Prunus amygdalus L. (almond shell for dye removal from aqueous solutions was investigated and methyl orange was used as a model compound. The effects of operational parameters including pH, ionic strength, adsorbent concentration and mesh size, dye concentration, contact time, and temperature on the removal of dye were evaluated. The adsorption kinetics conformed to the pseudo-second-order kinetic model. The equilibrium data pointed out excellent fit to the Langmuir isotherm model with maximum monolayer adsorption capacity of 41.34 mg g−1 at 293 K. Thermodynamic analysis proved a spontaneous, favorable, and exothermic process. It can be concluded that almond shell might be a potential low-cost adsorbent for methyl orange removal from aqueous media.

  3. Corrosion Inhibition and Adsorption Properties of Ethanolic Extract of Calotropis for Corrosion of Aluminium in Acidic Media

    OpenAIRE

    Sudesh Kumar; Suraj Prakash Mathur

    2013-01-01

    The corrosion inhibition of aluminium in sulfuric acid solution in the presence of different plant parts, namely, leaves, latex, and fruit was studied using weight loss method and thermometric method. The ethanolic extracts of Calotropis procera and Calotropis gigantea act as an inhibitor in the acid environment. The inhibition efficiency increases with increase in inhibitor concentration. The plant parts inhibit aluminium, and inhibition is attributed, due to the adsorption of the plant part...

  4. Adsorption Properties of Low-Cost Biomaterial Derived from Prunus amygdalus L. for Dye Removal from Water

    OpenAIRE

    Fatih Deniz

    2013-01-01

    The capability of Prunus amygdalus L. (almond) shell for dye removal from aqueous solutions was investigated and methyl orange was used as a model compound. The effects of operational parameters including pH, ionic strength, adsorbent concentration and mesh size, dye concentration, contact time, and temperature on the removal of dye were evaluated. The adsorption kinetics conformed to the pseudo-second-order kinetic model. The equilibrium data pointed out excellent fit to the Langmuir isother...

  5. The adsorption properties of Pb(II) and Cd(II) on functionalized graphene prepared by electrolysis method

    International Nuclear Information System (INIS)

    The functionalized graphene (GNSPF6) was fabricated by simple and fast method of electrolysis with potassium hexafluorophosphate solution as electrolyte under the static potential of 15 V. The characterization results of transmission electron microscopy, atom force microscopy, X-ray photoelectron spectroscopy, X-ray powder diffraction, Raman spectroscopy and thermogravimetric analysis indicate that graphite rod was completely exfoliated to graphene layer containing 30 wt.% PF6- with the average thickness ca. 1.0 nm. Our sample of GNSPF6 was developed for the removal of Pb(II) or Cd(II) ions from water, and the determined adsorption capacities are 406.6 mg/g (pH = 5.1) for Pb(II) and 73.42 mg/g (pH = 6.2) for Cd(II), which is much higher than that by our previous sample of GNSC8P and carbon nanotube. The adsorption processes reach equilibrium in just 40 min and the adsorption isotherms are described well by Langmuir and Freundlich classical isotherms models.

  6. Rapid adsorption properties of flower-like BiOI nanoplates synthesized via a simple EG-assisted solvothermal process

    International Nuclear Information System (INIS)

    Uniform well-crystallized flower-like BiOI nanoplates contained 3.7 nm mesopores, which may be attributed to the internanosheet spaces of BiOI with maximum pore diameters of about 30 nm, were successfully synthesized via a simple ethylene glycol-assisted solvothermal method. The as-prepared porous BiOI nanoplates exhibited excellent adsorption ability, and the saturated extent of adsorption of BiOI over an RhB solution was as high as 197 mg/g, which is much higher than those for BiOCl and BiOBr prepared via the same method and with a similar surface area. The probable adsorption mechanism could have originated from the interaction between the I atom in BiOI and a proton in RhB at different pH values and temperatures. With visible light irradiation (λ > 420 nm), 80 % of the RhB was degraded in 4 h, while BiOI still demonstrated reasonably outstanding photocatalytic ability under green light (λ = 550 ± 15 nm) because of its low-energy gap (1.72 eV). The degradation test for BiOI under irradiation at λ = 550 ± 15 nm is an excellent achievement for field applications because the catalyst can be applied in solar irradiation to remove organic pollutants, which may be of great value BiOI complex

  7. Mesoporous zirconium titanium oxides. Part 3. Synthesis and adsorption properties of unfunctionalized and phosphonate-functionalized hierarchical polyacrylonitrile-F-127-templated beads.

    Science.gov (United States)

    Sizgek, G Devlet; Griffith, Christopher S; Sizgek, Erden; Luca, Vittorio

    2009-10-01

    A method is presented for the preparation of zirconium titanate mixed oxides in bead form having hierarchical pore structure. This method entailed the use of both preformed polyacrylonitrile (PAN) polymer beads and surfactants as templates. The templates were removed by calcination at temperatures below about 500 degrees C, resulting in mixed oxide beads with trimodal pore size distributions and interconnected pores. The pore size distributions as determined using nitrogen adsorption-desorption showed clear maxima at 4.5 and 45 nm length scales and also clear evidence of microporosity. The macroporous framework morphology was a replica of the PAN beads with radial structure. The mesoporous framework possessed wormhole-like pores with pore size of about 6 nm that was consistent with the F-127 triblock copolymer template used. The mixed oxide beads exhibited surface areas of 215 and 185 m2/g after calcination at 500 and 600 degrees C. Thermal stability up to 650 degrees C is unprecedented for bulk systems. The adsorption properties were characterized using uranyl as the target cation and the mass transport in the beads with the present hierarchical architectures has been shown to be exceptional. The beads were functionalized with 4-amino,1-hydroxy,1,1-bis-phosphonic acid (HABDP) and amino-tris-methylene phosphonic acid (ATMP) and the adsorption properties for the extraction of uranyl sulfate complexes from acidic solution examined. Of the two molecules investigated, ATMP functionalization resulted in the best extraction efficiency with equilibrium uptake of about 90% of uranium available in solution between pH 1 and 2. The beads could potentially be utilized as catalysts, catalyst supports, adsorbents, and separation materials. PMID:19746937

  8. Adsorption Properties of MFM-400 and MFM-401 with CO2 and Hydrocarbons: Selectivity Derived from Directed Supramolecular Interactions.

    Science.gov (United States)

    Ibarra, Ilich A; Mace, Amber; Yang, Sihai; Sun, Junliang; Lee, Sukyung; Chang, Jong-San; Laaksonen, Aatto; Schröder, Martin; Zou, Xiaodong

    2016-08-01

    ([Sc2(OH)2(BPTC)]) (H4BPTC = biphenyl-3,3',5,5'-tetracarboxylic acid), MFM-400 (MFM = Manchester Framework Material, previously designated NOTT), and ([Sc(OH)(TDA)]) (H2TDA = thiophene-2,5-dicarboxylic acid), MFM-401, both show selective and reversible capture of CO2. In particular, MFM-400 exhibits a reasonably high CO2 uptake at low pressures and competitive CO2/N2 selectivity coupled to a moderate isosteric heat of adsorption (Qst) for CO2 (29.5 kJ mol(-1)) at zero coverage, thus affording a facile uptake-release process. Grand canonical Monte Carlo (GCMC) and density functional theory (DFT) computational analyses of CO2 uptake in both materials confirmed preferential adsorption sites consistent with the higher CO2 uptake observed experimentally for MFM-400 over MFM-401 at low pressures. For MFM-400, the Sc-OH group participates in moderate interactions with CO2 (Qst = 33.5 kJ mol(-1)), and these are complemented by weak hydrogen-bonding interactions (O···H-C = 3.10-3.22 Å) from four surrounding aromatic -CH groups. In the case of MFM-401, adsorption is provided by cooperative interactions of CO2 with the Sc-OH group and one C-H group. The binding energies obtained by DFT analysis for the adsorption sites for both materials correlate well with the observed moderate isosteric heats of adsorption for CO2. GCMC simulations for both materials confirmed higher uptake of EtOH compared with nonpolar vapors of toluene and cyclohexane. This is in good correlation with the experimental data, and DFT analysis confirmed the formation of a strong hydrogen bond between EtOH and the hydrogen atom of the hydroxyl group of the MFM-400 and MFM-401 framework (FW) with H-OEtOH···H-OFW distances of 1.77 and 1.75 Å, respectively. In addition, the accessible regeneration of MFM-400 and MFM-401 and release of CO2 potentially provide minimal economic and environmental penalties. PMID:27030923

  9. Application of adsorption methods to determine the effect of pH and Cu-stress on the changes in the surface properties of the roots

    Science.gov (United States)

    Szatanik-Kloc, Alicja

    2014-10-01

    Rye plants were grown in a nutrient solution prepared according to Hoagland for 2 weeks at pH 7, next for 14 days at pH 4.5 (without Cu+2) and in the presence of 20, 50, or 100 mg dm-3 copper ions. The control plants were grown continuously at pH 7. The physicochemical surface properties of the roots were examined using two adsorbates - polar (water vapour) and non-polar (nitrogen). The surface properties of the roots grown at pH 4.5 without Cu+2 were apparently the same as those of controls. The roots of rye which grew in the presence of Cu+2 were characterized by lower (relative to controls) specific surface area values. Statistically significant differences in the size of the apparent surface area (determined by water vapour) were reported for roots incubated with copper ions at a concentration of 20 and 50 mg dm-3. The average water vapour adsorption energy of the root surface decreased under the stress conditions. There were no statistically significant differences for the free surface area and characteristic energy of nitrogen adsorption.

  10. Acid/base bifunctional carbonaceous nanomaterial with large surface area: Preparation, characterization, and adsorption properties for cationic and anionic compounds

    International Nuclear Information System (INIS)

    Nanostructured carbonaceous materials are extremely important in the nano field, yet developing simple, mild, and “green” methods that can make such materials possess large surface area and rich functional groups on their surfaces still remains a considerable challenge. Herein, a one-pot and environment-friendly method, i.e., thermal treatment (180 °C; 18 h) of water mixed with glucose and chitosan (CTS), has been proposed. The resultant carbonaceous nanomaterials were characterized by field emitting scanning electron microscope, N2 adsorption/desorption, Fourier transform infrared spectroscope, X-ray photoelectron spectroscopy, and zeta-potential analysis. It was found that, in contrast to the conventional hydrothermally carbonized product from pure glucose, with low surface area (9.3 m2 g−1) and pore volume (0.016 cm3 g−1), the CTS-added carbonaceous products showed satisfactory textural parameters (surface area and pore volume up to 254 m2 g−1 and 0.701 cm3 g−1, respectively). Moreover, it was also interestingly found that these CTS-added carbonaceous products possessed both acidic (–COOH) and basic (–NH2) groups on their surfaces. Taking the advantages of large surface area and –COOH/–NH2 bifunctional surface, the carbonaceous nanomaterials exhibited excellent performance for adsorptions of cationic compound (i.e., methylene blue) at pH 10 and anionic compound (i.e., acid red 18) at pH 2, respectively. This work not only provides a simple and green route to prepare acid/base bifunctional carbonaceous nanomaterials with large surface area but also well demonstrates their potential for application in adsorption. - Highlights: • A simple and green method was proposed to prepare carbon nanomaterials. • The carbon product showed acid/base bifunctional surface with large surface area. • The carbon material could efficiently adsorb both cationic and anionic compounds

  11. Adsorption and catalytic hydrolysis of carbaryl and atrazine on pig manure-derived biochars: Impact of structural properties of biochars

    International Nuclear Information System (INIS)

    Highlights: ► High ash content biochar can increase solution pH and released metal ions. ► Ash in biochar can combine pesticide through specific interactions. ► Composition and structure of biochar is favor for the hydrolysis of pesticides. -- Abstract: Biochars were produced from pig manure to elucidate the influence of biochars with high ash contents on the fate of pesticides. Adsorption and catalytic hydrolysis of carbaryl and atrazine on original biochars and deashed biochars were investigated. The two pesticides were substantially adsorbed by the biochars, with organic carbon normalized sorption coefficient (Koc) values of 102.65–103.66 L/kg for carbaryl and 101.90–103.57 L/kg for atrazine at Ce of 0.5 mg/L. Hydrophobic effect alone could not explain the sorption, and several other processes including pore-filling and π–π electron donor–acceptor interactions were involved in pesticide adsorption. Adsorption increased greatly on the deashed biochar, indicating that some organic sorption sites in the original biochars were blocked or difficult to access due to their interactions with inorganic moiety. The pesticides were found to hydrolyze faster in the presence of biochars, and in the presence of biochar pyrolyzed at 700 °C, carbaryl and atrazine were decomposed by 71.8% and 27.9% in 12 h, respectively. The elevated solution pH was the main reason for the enhanced hydrolysis; however both the mineral surface and dissolved metal ions released from the biochars were confirmed to catalyze the hydrolysis

  12. Mesoporous hollow Zn2SiO4:Mn2+ nanospheres: The study of photoluminescence and adsorption properties

    International Nuclear Information System (INIS)

    Graphical abstract: Mesoporous hollow structure of Zn2SiO4:Mn2+ phosphors. - Highlights: • Mesoporous hollow Zn2SiO4:Mn2+ nanospheres are prepared via the layer-by-layer technique. • The Zn2SiO4:Mn2+ nanospheres exhibit better adsorption capabilities of Pb2+, Fe3+ than Cd2+. • The Zn2SiO4:Mn2+ nanospheres exhibit strong green emission around 524 nm. • With the increase of doped Mn2+ concentration, the emission peak shows a red-shift. - Abstract: Mesoporous hollow Zn2SiO4:Mn2+ nanospheres were prepared via the layer-by-layer technique using CTAB as surfactant. The structures/microstructures and morphologies of the as-synthesized phosphors were characterized by X-ray diffraction, scanning electron microscope, transmission electron microscope and N2 adsorption–desorption porosimetry. The adsorption capacity to remove toxic metal ions in water was tested and the results showed that the Zn2SiO4:Mn2+ nanospheres exhibited better adsorption capabilities of Pb2+, Fe3+ than Cd2+. Moreover, the as-obtained hollow Zn2SiO4:Mn2+ phosphors exhibited strong green emission around 524 nm at room temperature. When the atomic ratio of Zn to Mn was 97:3, the emission intensity of Zn2SiO4:Mn2+ phosphor was about 1.2 times that of commercial phosphors. Furthermore, with the increase of doped Mn2+ concentration, the emission peak showed a red-shift

  13. THE PREPARATION OF CROSSLINKED N,O—CARBOXYMETHYL CHITOSAN RESINS AND THEIR ADSORPTION PROPERTIES FOR TRIGLYCERIDE IN SERUM

    Institute of Scientific and Technical Information of China (English)

    YuYihau; GuHanqing

    1997-01-01

    Crosslinked N,O-carboxymethyl chitosan resins which can selectively adsorb triglyceride,were prepared by the reaction of N,O-carboxymethyl chitosan with glutaraldehyde solution.Adsorption experiments were performed by adding the resins to the serum.The results showed that this type of adsoirbent could cut down the concentration of triglyceride in serum by 56.4%(3.35mg/g resin)at most,while concentration of the total protein(TP) decreased only by 10.9% at least,so this novel adsorbent can be used to cure hypertriglyceridemia by hemoperfusion in the future.

  14. Growth of epitaxial Pt1-xPbx alloys by surface limited redox replacement and study of their adsorption properties.

    Science.gov (United States)

    Mercer, M P; Plana, D; Fermίn, D J; Morgan, D; Vasiljevic, N

    2015-10-01

    The surface limited redox replacement (SLRR) method has been used to design two-dimensional Pt-Pb nanoalloys with controlled thickness, composition, and structure. The electrochemical behavior of these alloys has been systematically studied as a function of alloy composition. A single-cell, two-step SLRR protocol based on the galvanic replacement of underpotentially deposited monolayers of Pb with Pt was used to grow epitaxial Pt1-xPbx (x galvanic replacement step, the Pb atomic content can be controlled in the films. Electrochemical analysis of the alloys showed that the adsorption of both H and CO exhibits similar, and systematic, decreases with small increases in the Pb content. These measurements, commonly used in electrocatalysis for the determination of active surface areas of Pt, suggested area values much lower than those expected based on the net Pt composition in the alloy as measured by XPS. These results show that Pb has a strong screening effect on the adsorption of both H and CO. Moreover, changes in alloy composition result in a negative shift in the potential of the peaks of CO oxidation that scales with the increase of Pb content. The results suggest electronic and bifunctional effects of incorporated Pb on the electrochemical behavior of Pt. The study illustrates the potential of the SLRR methodology, which could be employed in the design of 2-dimensional bimetallic Pt nanoalloys for fundamental studies of electrocatalytic behavior in fuel cell reactions dependent on the nature of alloying metal and its composition. PMID:26372676

  15. Immobilization of functional materials onto poly (styrene-co-divinylbenzene) gels by gamma irradiation and adsorption properties

    International Nuclear Information System (INIS)

    Pectin and triallylisocyanurate (TAIC) were immobilized onto poly(styrene-co-divinylbenzene) (PSD) beads by irradiating in the range of 2.5 to 25 kGy using γ-rays from a 60Co source. The adsorption performance of methyl-2-benzimidazolylcarbamate (MBC) treated with immobilized Pectin-TAIC beads was investigated. Pectin was effective to enhance the MBC uptakes at pH 11, in contrast to pH 3 for TAIC. The amounts of MBC uptake of immobilized Pectin-TAIC beads were 1.3-3.9 times higher than those of PSD beads which were only irradiated without the use of Pectin and TAIC in the range of pH 3 to pH 11. The difference was due to the introduction of both the hydrophilicity and hydrophobicity for immobilized beads by γ-irradiation. Ten cycles of adsorption-desorption assays show that the sorption performance of immobilized Pectin-TAIC beads shows excellent reproducibility, suggesting that the immobilized Pectin-TAIC beads are a useful adsorbent for the extraction of MBC from environmental water. (author)

  16. Studies on Adsorption and Corrosion Inhibitive Properties of Indoline Compounds on N80 Steel in Hydrochloric Acid

    Science.gov (United States)

    Yadav, M.; Sarkar, T. K.; Purkait, Taniya

    2015-12-01

    Corrosion inhibition performance of synthesized indoline compounds, namely, 3'-(4-(1-acetyl-5-(4-methoxyphenyl)-4,5-dihydro-1H-pyrazol-3-yl)phenyl)spiro[indoline-3,2'-thiazolidine]-2,4'-dione (MPIT ) and 1-(4-(1-acetyl-5-(4-methoxyphenyl)-4,5-dihydro-1H-pyrazol-3-yl)phenyl)spiro[imidazolidine-2,3'-indoline]-2',5-dione (MPII) on N80 steel in 15% HCl solution was studied using weight loss measurement, potentiodynamic polarization, and electrochemical impedance spectroscopy (EIS) techniques. Polarization studies showed that both studied inhibitors were of mixed type in nature. The adsorption of inhibitors on the N80 steel surface obeys Langmuir adsorption isotherm. The potential of zero charge ( E PZC) for the N80 steel was determined by EIS method. Scanning electron microscopy, energy-dispersive x-ray spectroscopy, and atomic force microscopy were used to characterize the surface morphology of uninhibited and inhibited N80 steel specimens. The density functional theory was employed for theoretical calculations.

  17. Acid/base bifunctional carbonaceous nanomaterial with large surface area: Preparation, characterization, and adsorption properties for cationic and anionic compounds

    Energy Technology Data Exchange (ETDEWEB)

    Li, Kai; Ma, Chun–Fang; Ling, Yuan; Li, Meng [Department of Chemistry, Faculty of Material Science and Chemistry, China University of Geosciences, Wuhan 430074 (China); Gao, Qiang, E-mail: gaoqiang@cug.edu.cn [Department of Chemistry, Faculty of Material Science and Chemistry, China University of Geosciences, Wuhan 430074 (China); Engineering Research Center of Nano-Geo Materials of Ministry of Education, China University of Geosciences, Wuhan 430074 (China); Luo, Wen–Jun, E-mail: heartnohome@yahoo.com.cn [Department of Chemistry, Faculty of Material Science and Chemistry, China University of Geosciences, Wuhan 430074 (China)

    2015-07-15

    Nanostructured carbonaceous materials are extremely important in the nano field, yet developing simple, mild, and “green” methods that can make such materials possess large surface area and rich functional groups on their surfaces still remains a considerable challenge. Herein, a one-pot and environment-friendly method, i.e., thermal treatment (180 °C; 18 h) of water mixed with glucose and chitosan (CTS), has been proposed. The resultant carbonaceous nanomaterials were characterized by field emitting scanning electron microscope, N{sub 2} adsorption/desorption, Fourier transform infrared spectroscope, X-ray photoelectron spectroscopy, and zeta-potential analysis. It was found that, in contrast to the conventional hydrothermally carbonized product from pure glucose, with low surface area (9.3 m{sup 2} g{sup −1}) and pore volume (0.016 cm{sup 3} g{sup −1}), the CTS-added carbonaceous products showed satisfactory textural parameters (surface area and pore volume up to 254 m{sup 2} g{sup −1} and 0.701 cm{sup 3} g{sup −1}, respectively). Moreover, it was also interestingly found that these CTS-added carbonaceous products possessed both acidic (–COOH) and basic (–NH{sub 2}) groups on their surfaces. Taking the advantages of large surface area and –COOH/–NH{sub 2} bifunctional surface, the carbonaceous nanomaterials exhibited excellent performance for adsorptions of cationic compound (i.e., methylene blue) at pH 10 and anionic compound (i.e., acid red 18) at pH 2, respectively. This work not only provides a simple and green route to prepare acid/base bifunctional carbonaceous nanomaterials with large surface area but also well demonstrates their potential for application in adsorption. - Highlights: • A simple and green method was proposed to prepare carbon nanomaterials. • The carbon product showed acid/base bifunctional surface with large surface area. • The carbon material could efficiently adsorb both cationic and anionic compounds.

  18. Carbon nanomaterials for gas adsorption

    CERN Document Server

    Terranova, Maria Letizia

    2012-01-01

    Research in adsorption of gases by carbon nanomaterials has experienced considerable growth in recent years, with increasing interest for practical applications. Many research groups are now producing or using such materials for gas adsorption, storage, purification, and sensing. This book provides a selected overview of some of the most interesting scientific results regarding the outstanding properties of carbon nanomaterials for gas adsorption and of interest both for basic research and technological applications. Topics receiving special attention in this book include storage of H, purific

  19. Modification of electronic properties during adsorption of conjugate organic molecules on the surface of polycrystalline SnO2

    Science.gov (United States)

    Komolov, A. S.; Komolov, S. A.; Lazneva, E. F.; Gavrikov, A. A.; Repin, P. S.

    2012-02-01

    The modification of the electronic structure during adsorption of ultrathin copper phthalocyanine (CuPc) and 3, 4, 9, 10 perylene-tetracarboxylic-dianhydride (PTCDA) coatings on the surface of polycrystalline tin dioxide is traced. Auger electron spectroscopy is employed to find changes in the atomic composition of the surface. It is found with the help of low-energy electron total current spectroscopy using a testing beam of electrons with energies up to 30 eV that the total current spectra typical of organic films are formed when the thickness of the coating being deposited is 2-7 nm. The formation of an interface layer 1.5-2.0 nm in thickness is detected, in which the intensity of the structure of the total current spectra decreases and the effect of interaction of PTCDA molecules with the SnO2 surface is manifested.

  20. Adsorption and switching properties of a N-benzylideneaniline based molecular switch on a Au(111) surface

    International Nuclear Information System (INIS)

    High resolution electron energy loss spectroscopy has been employed to analyze the adsorption geometry and the photoisomerization ability of the molecular switch carboxy-benzylideneaniline (CBA) adsorbed on Au(111). CBA on Au(111) adopts a planar (trans) configuration in the first monolayer (ML) as well as for higher coverages (up to 6 ML), in contrast to the strongly nonplanar geometry of the molecule in solution. Illumination with UV light of CBA in direct contact with the Au(111) surface (≤1 ML) caused no changes in the vibrational structure, whereas at higher coverages (>1 ML) pronounced modifications of vibrational features were observed, which we assign to a trans→cis isomerization. Thermal activation induced the back reaction to trans-CBA. We propose that the photoisomerization is driven by a direct (intramolecular) electronic excitation of the adsorbed CBA molecules in the second ML (and above) analogous to CBA in the liquid phase.

  1. Statistical properties of abnormal nano-sized adsorbate islands growth in a model of adsorptive multilayer system

    Science.gov (United States)

    Kharchenko, Vasyl O.; Kharchenko, Dmitrii O.

    2015-07-01

    A generalized model for nano-sized islands growth in substratum-mediated adsorption multilayer system is proposed. It is shown that the system manifests cascade of first order transitions related to the number of growing atomic layers. We have found that pattern formation on low layers is governed by a rate of adatom transference between neighboring layers. Critical coverage and critical island size governing adsorbate islands formation are defined. Anomalous dynamics of adsorbate island size growth and a crossover of dynamical regimes are discussed. Distributions of adsorbate/vacancy islands over their sizes are studied in details. It is shown that the linear size of vacancy/adsorbate islands varies from 20 to 100 nm.

  2. Diversity and As-adsorption properties of Mn(II)-oxidizing bacteria within tropical wetlands of the Mekong Delta

    Science.gov (United States)

    Ying, S. C.; Kocar, B. D.; Fendorf, S.; Francis, C. A.

    2007-12-01

    Manganese (Mn) and iron (Fe) oxides are ubiquitous minerals that occur under similar redox conditions in terrestrial systems and have high sorptive capacities for many trace metals, including arsenic (As). In most natural environments, Fe oxidation is dominated by abiotic processes, while Mn oxides are primarily formed via bacterial Mn(II) oxidation, and both processes can profoundly impact the mobility of metal(loid) contaminants. Deciphering the mechanisms involved in arsenic transport within soils and sediments is essential for aiding many Southeast Asian countries, including Cambodia, where naturally occurring As is in groundwater at concentrations well above the WHO recommended limit. Although numerous past studies have characterized the effects of As adsorption onto Fe and Mn oxides individually, it is unknown whether, in the presence of both oxides, there is preferential adsorption of As onto one oxide over the other. In the present study, we examine the competitive retention of As(III) and As(V) on goethite and biogenic Mn oxides using Donnan membranes--where each oxides is isolated by a semi-permeable membrane through which arsenic can migrate. Mn(II)-oxidizing bacteria, isolated from several Mn-rich sites along the Mekong River and wetland areas within the Mekong delta, were dominated by a diverse array of Bacillus strains that rapidly oxidize Mn(II) within three to five days in liquid culture. The results of this study not only expand our knowledge of the diversity and biogeochemical importance of terrestrial Mn(II)-oxidizing bacteria, but also contribute to our understanding the relative impact of Fe and Mn oxides on arsenic retention within natural wetlands.

  3. Selective adsorption of tannins onto hide collagen fibres

    Institute of Scientific and Technical Information of China (English)

    廖学品; 陆忠兵; 石碧

    2003-01-01

    Hide collagen of animals is used to prepare adsorbent material and its adsorption properties to tannins are investigated. It is indicated that the collagen fibres has excellent adsorption selectivity and high adsorption capacity to tannins. The adsorption rate of tannins is more than 90% whilst less than 10% of functional components are retained by the adsorbent. The adsorption mechanism of tannins onto hide collagen fibres is hydrogen-bonding association. Freundlich model can be used to describe the adsorption isotherms, and the pseudo-second-order rate model can be used to describe adsorption kinetics.

  4. A two-fold interpenetrated flexible bi-pillared-layer framework of Fe(II) with interesting solvent adsorption property

    Indian Academy of Sciences (India)

    Ritesh Haldar; Tapas Kumar Majia

    2011-11-01

    A two-fold interpenetrated microporous bi-pillared-layer framework of Fe(II), {[Fe(2,6-napdc)(4,4'-bipy)](EtOH)(H2O)} (1) (2,6-napdc =2,6-naphthalenedicarboxylate; 4,4'-bipy=4,4'-bipyridine) composed of mixed ligand system has been synthesized and structurally characterized. The 2,6-napdc linkers form a 2D corrugated sheet of {Fe(2,6-napdc)} by linking the secondary building unit of Fe2(CO2)2 in the plane, which are further connected by double 4,4'-bipy pillars resulting in a bi-pillared-layer type 3D framework. The 3D framework is two-fold interpenetrated and exhibits a 3D channel structure (4.0 × 3.5, 1.5 × 0.5 and 2.2 × 2.1 Å2) occupied by the guest water and ethanol molecules. Framework 1 shows high thermal stability, and the desolvated framework (1′) renders permanent porosity realized by N2 adsorption profile at 77K (BET surface area of ∼ 52 m2 g-1). Moreover, the framework 1′ also uptakes different solvent vapours (water, methanol and ethanol) and their type-I profile suggest strong interaction with pore surfaces and overall hydrophilic nature of the framework. Temperature dependent magnetic measurements suggest overall antiferromagnetic behaviour in compound 1.

  5. CdS nanocrystals/TiO2/crosslinked chitosan composite: Facile preparation, characterization and adsorption-photocatalytic properties

    International Nuclear Information System (INIS)

    CdS nanocrystals deposited on TiO2/crosslinked chitosan composite (CdS/TiO2/CSC) were prepared in an attempt to photocatalyze decolorization of water soluble azo dye in aqueous solution under simulated solar light irradiation. CdS/TiO2/CSC was characterized by X-ray diffraction (XRD), energy-dispersive spectroscopy (EDS), and scanning electron microscopy (SEM). The characterization results proved that CdS nanocrystals has successfully been deposited on/in TiO2/crosslinked chitosan composite. The adsorption ability of CdS/TiO2/CSC was approximately 2.66 mg methyl orange (a typical water soluble azo dye) per gram. The photocatalytic decolorization of methyl orange solution reached 99.1% by CdS/TiO2/CSC after simulated solar light irradiation for 210 min. Kinetics analysis indicated that photocatalytic decolorization of methyl orange solution by CdS/TiO2/CSC obeyed first-order kinetic Langmuir-Hinshelwood mechanism (R2 > 0.997). CdS/TiO2/CSC exhibited enhanced photocatalytic activity under simulated solar light irradiation compared with photocatalysts reported before and the photocatalytic activity of CdS/TiO2/CSC maintained at 89.0% of initial decolorization rate after five batch reactions. The presence of NO3− accelerated the decolorization of methyl orange solution by CdS/TiO2/CSC, while SO42− and Cl− had an inhibitory effect on the decolorization of methyl orange. Therefore, present experimental results indicated to assess the applicability of CdS/TiO2/CSC as a suitable and promising photocatalyst for effective decolorization treatment of dye-containing effluents.

  6. Inhibiting properties and adsorption of an amine based fatty acid corrosion inhibitor on carbon steel in aqueous carbon dioxide solutions

    Energy Technology Data Exchange (ETDEWEB)

    Buchweishaija, Joseph

    1997-12-31

    Carbon dioxide corrosion is a major corrosion problem in oil and gas production systems and many organic inhibitors have been tested and used to protect the substrate from corrosion. This thesis studies the mechanism of interaction of the inhibitor molecule with the metallic substrate and how this affects the dissolution rate of the metal. The performance of a commercial amine based fatty acid corrosion inhibitor has been investigated using rotating cylinder electrodes and carbon steel electrodes in CO{sub 2} saturated formation water in the temperature range between 35 to 80{sup o}C. The corrosion process was monitored by electrochemical impedance measurements, and at the end of each experiment full polarization curves were recorded. When the inhibitor was applied on noncorroded electrodes, high inhibitor performance, over 99.7%, was observed independent of temperature. On precorroded electrodes inhibitor performance was found to depend on temperature and time of precorrosion. Above 60{sup o}C, the inhibitor performance decreased with increasing time of precorrosion, presumably because of the formation of a corrosion film of either iron carbonate or a combination of iron carbonate and iron carbide which prevent the inhibitor from reaching the surface. The inhibitor protection efficiency was assumed to be associated with the degree of inhibitor coverage at the material surface, and adsorption isotherms have been calculated in the concentration range between 0.1 ppm and 100 ppm. A Langmuir isotherm was found to give the best fit. The inhibitor performance on a 2 days precorroded rotating electrode was investigated at different solution pH ranging between 4.5 and 6.5 at 35{sup o}C. 130 refs., 80 figs., 22 tabs.

  7. Production of granular activated carbon from food-processing wastes (walnut shells and jujube seeds) and its adsorptive properties.

    Science.gov (United States)

    Bae, Wookeun; Kim, Jongho; Chung, Jinwook

    2014-08-01

    Commercial activated carbon is a highly effective absorbent that can be used to remove micropollutants from water. As a result, the demand for activated carbon is increasing. In this study, we investigated the optimum manufacturing conditions for producing activated carbon from ligneous wastes generated from food processing. Jujube seeds and walnut shells were selected as raw materials. Carbonization and steam activation were performed in a fixed-bed laboratory electric furnace. To obtain the highest iodine number, the optimum conditions for producing activated carbon from jujube seeds and walnut shells were 2 hr and 1.5 hr (carbonization at 700 degrees C) followed by 1 hr and 0.5 hr (activation at 1000 degrees C), respectively. The surface area and iodine number of activated carbon made from jujube seeds and walnut shells were 1,477 and 1,184 m2/g and 1,450 and 1,200 mg/g, respectively. A pore-distribution analysis revealed that most pores had a pore diameter within or around 30-40 angstroms, and adsorption capacity for surfactants was about 2 times larger than the commercial activated carbon, indicating that waste-based activated carbon can be used as alternative. Implications: Wastes discharged from agricultural and food industries results in a serious environmental problem. A method is proposed to convert food-processing wastes such as jujube seeds and walnut shells into high-grade granular activated carbon. Especially, the performance of jujube seeds as activated carbon is worthy of close attention. There is little research about the application ofjujube seeds. Also, when compared to two commercial carbons (Samchully and Calgon samples), the results show that it is possible to produce high-quality carbon, particularly from jujube seed, using a one-stage, 1,000 degrees C, steam pyrolysis. The preparation of activated carbon from food-processing wastes could increase economic return and reduce pollution. PMID:25185390

  8. Adsorption and wetting.

    NARCIS (Netherlands)

    Schlangen, L.J.M.

    1995-01-01

    Adsorption and wetting are related phenomena. In order to improve knowledge of both and their relations, experiments, thermodynamics and a theoretical interpretation have been connected, starring n-alkanes.Starting from the Gibbs adsorption equation thermodynamic relations between vapour adsorption

  9. Effects of wood polymers and extractives on the adsorption of wet-end chemicals and the properties of the sheet - MPKY 03

    Energy Technology Data Exchange (ETDEWEB)

    Bobacka, V.; Lindholm, J.; Nurmi, M.; Naesman, J. [Aabo Akademi, Turku (Finland). Lab. of Paper Chemistry; Holmbom, B.; Konn, J.; Sundberg, A.; Willfoer, S. [Aabo Akademi, Turku (Finland). Lab. of Forest Products Chemistry

    1998-12-31

    The effects of deposition of dissolved and colloidal substances (disco, DCS) together with fixing agents on the wet end chemistry, and the paper quality have been studied. Increased amounts of wood resin in handsheets results in lower strength properties and friction of the sheets. Addition of isolated polysaccharides together with wood resin results in higher strength properties compared, at the same resin content, to sheets without added polysaccharides. Disco substances released from TMP were adsorbed/deposited onto different fillers. It is possible to determine the distribution of aggregated wood resin in handsheets of kraft pulp by confocal laser scanning microscopy. Addition of iron salts to a TMP suspension results in a decrease in the brightness of the fibers. The adsorption of cationic starch and cationic polyacrylamide was studied as well as the flocculation of a peroxide bleached TMP and mixture of TMP and kraft pulp in the presence of retention aids and fixing agents. The fixing agent had a minor effect on the flocculation in peroxide bleached TMP, while cationic starch induced flocculation after a threshold. When added together, cationic starch induced flocculation immediately. The retention of carbohydrates in the mixture was not much influenced by the presence of fixing agents and retention aids, but the extractives were efficiently retained. Colloidal substances adsorb both cationic starch and polyacrylamide. Of the dissolved substances, pectic acids are most efficiently aggregated. (orig.)

  10. Effect of pore structure and surface chemical properties on adsorption properties of activated carbons%孔结构和表面化学性质对活性炭吸附性能的影响

    Institute of Scientific and Technical Information of China (English)

    刘立恒; 辜敏; 鲜学福

    2012-01-01

    Adsorption isotherms of CO2,CH4 and N2 on three granular activated carbons(GAC-C,GAC-P and GAC-T) were determined at room temperature.Pore structure and surface chemical properties of granular activated carbons were characterized,and the effect of them on adsorption properties was investigated.The results showed that the relationships of gases adsorption capacity and uptake coefficient on granular activated carbons were CO2〉CH4〉N2,because of the differences of adsorption mechanism,pore structure,surface functional groups and molecular polarity.The adsorption capacities of CH4 and N2 were mainly controlled by micropore volume of activated carbon,and the differences of N2 and CO2 adsorption capacity were affected by micropores from 0.572 to 2.0 nm and pores from 0.4 to 6.0 nm,respectively.And uptake coefficient of CH4,was more relational with mesopore and macropore,while uptake coefficients of N2 and CO2 were mainly controlled by micropore and macropore,respectively.%测定了室温下3种活性炭(GAC-C、GAC-P和GAC-T)对CO2、CH4和N2的吸附性能,并对颗粒活性炭孔结构和表面化学性质进行了表征,探讨了孔结构和表面化学性质对活性炭吸附性能的影响。结果表明:由于吸附机理、孔结构、表面含氧官能团和分子极性的差异,CO2、CH4和N2在活性炭上的饱和吸附量和吸附常数的关系为CO2〉CH4〉N2;CH4和N2的饱和吸附量主要受活性炭微孔孔容的影响,N2和CO2饱和吸附量的差异分别是由0.572~2.0 nm的微孔和0.4~6 nm的孔引起的;CH4吸附常数主要受较大中孔和大孔影响,N2吸附常数与微孔密切相关,大孔对CO2的吸附常数影响最大。

  11. Geometrical Properties Can Predict CO2 and N2 Adsorption Performance of Metal-Organic Frameworks (MOFs) at Low Pressure.

    Science.gov (United States)

    Fernandez, Michael; Barnard, Amanda S

    2016-05-01

    Metal-organic frameworks (MOFs) are nanoporous materials with exceptional host-guest properties poised for groundbreaking innovations in gas separation applications according to high-throughput (HT) screening data. However, MOF structural libraries are nearly infinite in practice and so statistical and information technology will play a fundamental role in implementing and rationalizing MOF virtual screening. In this work, we apply k-means clustering and archetypal analysis (AA) to identify the truly significant nanoporous structures in a large library of ∼82 000 virtual MOFs. Quantitative structure-property relationship (QSPR) models of the theoretical CO2 and N2 uptake capacities were also developed using a calibration set of ∼16 000 hypothetical MOF structures derived from the prototypes and archetype frameworks. Since uptake capacities correlated poorly to the void fraction, surface area and pore size but these properties were used to build binary classifier predictors that successfully identify "high-performing" nanoporous materials in an external test set of ∼65 000 MOFs with accuracy higher than 94%. The accuracy of the classification decreased for MOFs with fluorine substituents. The classification models can serve as efficient filtering tools to detecting promising high-performing candidates at the early stage of virtual high-throughput screening of novel porous materials. PMID:27022760

  12. Adsorption of phenol on wood surfaces

    Science.gov (United States)

    Mamleeva, N. A.; Lunin, V. V.

    2016-03-01

    Adsorption of phenol on aspen and pine wood is investigated. It is shown that adsorption isotherms are described by the Langmuir model. The woods' specific surface areas and adsorption interaction constants are determined. It is found that the sorption of phenol on surfaces of aspen and pine is due to Van der Waals interactions ( S sp = 45 m2/godw for aspen and 85 m2/godw for pine). The difference between the adsorption characteristics is explained by properties of the wood samples' microstructures.

  13. Adsorption Properties of PVA/PAA/clay Composite Hydrogel Synthesized by Gamma Radiation and its Application in Removal of Crystal Violet Dye from Its Aqueous Solution

    International Nuclear Information System (INIS)

    Copolymer hydrogels composed of Poly vinyl alcohol (PVA) and Poly acrylic acid (PAA) were prepared by γ-irradiation in the presence of N,N’ methylene bis acrylamide (MBAM) as crosslinking agent or bentonite clay. The copolymers were characterized by FTIR and SEM. The dye adsorption experiments for Crystal Violet dye (CV) were carried out by using bath procedure. UV-visible absorption spectroscopy was used to determine the adsorption behavior. The effect of different copolymer composition, clay concentration, ph, contact time, adsorbent dose, initial dye concentration, and adsorption temperature were investigated to obtain the best experimental conditions. The adsorption equilibrium was attained after about 24h. of contact time. It was found that the adsorption process was correlated with Freundlich isotherm equation. Kinetic and thermodynamic studies of CV dye onto the prepared hydrogels were also evaluated

  14. DFT modelling of hydrogen sulphide adsorption on α-Cr2O3 (0001) surface

    Science.gov (United States)

    Maldonado, Frank; Stashans, Arvids

    2016-05-01

    Density functional theory has been used to predict properties of hydrogen sulphide, H2S, adsorption on the α-Cr2O3 (0001) surface. Five energetically most favourable adsorption configurations have been selected for the study. Our work reveals adsorption geometries as well as discusses electronic and magnetic properties of the adsorbate on chromium oxide surface. It is shown that two different adsorption types, namely molecular adsorption and dissociative adsorption, can take place leading to two sets of adsorption energies. The most favourable arrangement is found to correspond to the case of dissociative adsorption with molecular hydrogen forming OH group at the α-Cr2O3 (0001) surface.

  15. Optimization of fermentation conditions and properties of an exopolysaccharide from Klebsiella sp. H-207 and application in adsorption of hexavalent chromium.

    Directory of Open Access Journals (Sweden)

    Li Qiang

    Full Text Available The novel exopolysaccharide HZ-7 is produced by Klebsiella sp. H-207, and its fermentation conditions were optimized by response surface methodology (RSM. In this study, the optimized medium consisted of sucrose 31.93 g/L, KNO(3 2.17 g/L and K(2HPO(4 5.47 g/L; while the optimized culture conditions consisted of seed age 13 h, with an inoculum size of 10.6% and incubation temperature of 28.9°C. A maximum HZ-7 yield of about 15.05 g/L was achieved under the optimized conditions using RSM and single-factor experiments. Next the exopolysaccharide HZ-7 was partially purified and characterized. The resulting product showed good properties, such as high concentration of uronic acid (41.67%, low average molecular weight (about 1.94×10(5 Da and porous surface structure, were very advantageous to biosorption. Therefore HZ-7 was applied to absorb hexavalent chromium (Cr(VI. The maximum adsorption efficiency (99.2% which was obtained at an initial pH of 1.0 along with an initial Cr(VI concentration of 20 mg/L, was not affected by ordinary metal ions and temperature. These data suggest Klebsiella sp. H-207 exopolysaccharide will be promising potential for industrial application.

  16. Adsorption at the biocompatible α-pinene-water interface and emulsifying properties of two eco-friendly surfactants.

    Science.gov (United States)

    Trujillo-Cayado, Luis Alfonso; Ramírez, Pablo; Alfaro, María Carmen; Ruíz, Manuela; Muñoz, José

    2014-10-01

    In this contribution, we provide an accurate characterization at the α-pinene/water interface of two commercial polyoxytheylene glycerol ester surfactants which differ in the number of ethylene oxide (EO) groups, comprising a systematic analysis of interfacial pressure isotherms, dynamic curves, interfacial rheology and emulsifying properties. Polyoxyethylene glycerol esters derived from cocoa oil are non-ionic surfactants obtained from a renewable source which fulfill the environmental and toxicological requirements to be used as eco-friendly emulsifying agents. α-Pinene is a renewable biosolvent completely insoluble in water, which could find numerous applications. Interfacial rheology and equilibrium interfacial pressure data fitted a rigorous reorientation model that assumes that the surfactant molecules, when adsorbed at the interface, can acquire two orientations. The surfactant with the highest number of EO groups (Levenol C201) turned out to be more surface active at the α-pinene/water interface. In addition, the surfactant with the lowest number of EO groups (Levenol H&B) is solubilized into the adjacent oil phase. Slightly concentrated α-pinene emulsions were obtained using both surfactants. Nevertheless, more stable α-pinene emulsions with smaller droplet sizes and lower polidispersity were obtained when Levenol C201 was used as emulsifier instead of Levenol H&B. The systematic characterization presented in this work provides important new findings on the interfacial and emulsifying properties of polyoxytheylene glycerol ester surfactants, which can be applied in the rational development of new biocompatible products. PMID:25129697

  17. Study on adsorption properties of crosslinked xanthated chitosan for Pb2+%交联黄原酸壳聚糖对铅离子的吸附研究

    Institute of Scientific and Technical Information of China (English)

    王崇侠; 宋庆平; 丁纯梅

    2012-01-01

    In this work, crosslinked xanthated chitosan was prepared from crosslinking and xanthate reaction using chitosan as materials and its structure were characterized by XRD,FT-IR Its adsorption properties toward Pb2+were studied and various adsorption factors were further studied,including initial pH value,adsorption temperature and adsorption time. The results showed that the adsorption capability of chitosan and crosslinked xanthated chitosan to Pb2+ are 126. 8mg/g,238. 9mg/g respectively,when it was initiated at[ Pb2+ ]0.01M ,pH S and kept at 25℃ for 2 h. The adsorption capability of crosslinked xanthated chitosan is 1. 89 times of chitosan.%以壳聚糖为原料,通过交联和黄原酸化反应制备出交联黄原酸壳聚糖,采用FT-IR和XRD表征了其结构,并探讨壳聚糖及交联黄原酸壳聚糖对pb2+的吸附性能.研究了初始溶液pH值、温度以及吸附时间等因素对Pb2+吸附量的影响.结果表明,在Pb2+起始浓度0.01 M,起始溶液pH=5,室温25℃吸附2h条件下,壳聚 糖和交联黄原酸壳聚糖对铅离子的吸附量分别为126.8 mg/g和238.9 mg/g,交联黄原酸壳聚糖吸附能力为壳聚糖的1.89倍.

  18. Adsorption at the air-water interface and emulsification properties of grain legume protein derivatives from pea and broad bean.

    Science.gov (United States)

    Tsoukala, A; Papalamprou, E; Makri, E; Doxastakis, G; Braudo, E E

    2006-12-01

    Functional properties of native and modified (through induced autolysis) pea (Pisum sativum L.) and broad bean (Vicia faba L.) protein derivatives are studied. In specific, protein solubility and behavior at the air-water interface through surface pressure measurements are investigated. Furthermore the ability of the protein products to act as emulsifying agents and to stabilize emulsions is studied through oil droplet size distribution measurements and by the protein adsorbed at the oil-water interface. The data reveal that the ability of the proteins to act as surfactants and build up a rigid film around the oil droplets, mainly depends on their suitable molecular configuration and structure. Hydrolysis did not promote the functionality of the legume proteins. Broad bean exhibited better functionality than pea, before and after hydrolysis. Some comparisons were also made with lupin (Lupinus albus L.) protein isolate. PMID:17049437

  19. Effect of copper stress on growth characteristics and fermentation properties of Saccharomyces cerevisiae and the pathway of copper adsorption during wine fermentation.

    Science.gov (United States)

    Sun, Xiangyu; Liu, Lingling; Zhao, Yu; Ma, Tingting; Zhao, Fang; Huang, Weidong; Zhan, Jicheng

    2016-02-01

    The effect of copper stress on the fermentation performance of Saccharomyces cerevisiae and its copper adsorption pathway during alcoholic fermentation were investigated in this study. At the limits imposed by the regulations of the European Union and South African (⩽ 20 mg/l), copper had no effect on the cell growth of S. cerevisiae, but its fermentation performance was inhibited to a certain extent. Therefore, the regulated limit should be further reduced (⩽ 12.8 mg/l). Under 9.6-19.2 mg/l copper stress, S. cerevisiae could absorb copper; the copper removal ratio and the unit strain adsorption were 60-81% and 2.72-9.65 mg/g, respectively. S. cerevisiae has a non-biological adsorption of copper, but compared with biological (living yeast) adsorption, the non-biological adsorption was very low. The copper adsorption way of S. cerevisiae was primarily via biological (living yeast) adsorption, which was a two-step process. PMID:26304318

  20. Adsorption and wetting.

    OpenAIRE

    Schlangen, L.J.M.

    1995-01-01

    Adsorption and wetting are related phenomena. In order to improve knowledge of both and their relations, experiments, thermodynamics and a theoretical interpretation have been connected, starring n-alkanes.Starting from the Gibbs adsorption equation thermodynamic relations between vapour adsorption and wetting are derived. The surface pressure of a film, formed by vapour adsorption on a solid surface, is calculated by integrating the vapour adsorption isotherm. The surface pressure at the sat...

  1. Microcalorimetric Study of the Catalytic Properties of SBA-15 Modified with Cu or Fe for Adsorption/Oxidation of methyl mercaptane

    Directory of Open Access Journals (Sweden)

    Liliana Giraldo

    2014-01-01

    Full Text Available SBA-15 modified with Cu or Fe was used for adsorption/oxidation of methyl mercapthane in the vapour phase. These solids were synthesized from SBA-15 using the template method with a non-ionic surfactant and impregnating the SBA-15 with Cu and Fe. The solids were characterized by using XRD, FTIR and isotherms of adsorption in N2. An increase in the surface area, pore volume and mesoporosity of the SBA-15 with each metal was observed. Adsorption microcalorimetry is an effective method to measure thermal effects generated during the decomposition of methyl mercapthane.

  2. The chemical properties of bimetallic surfaces: Importance of ensemble and electronic effects in the adsorption of sulfur and SO 2

    Science.gov (United States)

    Rodriguez, José A.

    The understanding of the interaction of sulfur with bimetallic surfaces is a critical issue for preventing the deactivation of hydrocarbon reforming catalysts and for the design of better hydrodesulfurization catalysts. The alloying or combination of two metals can lead to materials with special chemical properties due to an interplay of “ensemble” and “electronic” effects. In recent years, several new interesting phenomena have been discovered when studying the interaction of sulfur with bimetallic surfaces using the modern techniques of surface science. Very small amounts of sulfur are able to induce dramatic changes in the morphology of bimetallic surfaces that combine noble metals (Cu, Ag, Au) and transition metals. This phenomenon can lead to big modifications in the activity and selectivity of bimetallic catalysts used for hydrocarbon reforming. In many cases, bimetallic bonding produces a significant redistribution of charge around the bonded metals. The electronic perturbations associated with the formation of a heteronuclear metal-metal bond can affect the reactivity of the bonded metals toward sulfur. This can be a very important issue to consider when trying to minimize the negative effects of sulfur poisoning (Sn/Pt versus Ag/Pt and Cu/Pt catalysts) or when trying to improve the performance of desulfurization catalysts (Co/Mo and Ni/Mo systems). Clearly much more work is necessary in this area, but new concepts are emerging that can be useful for designing more efficient bimetallic catalysts.

  3. Adsorption properties of the nanozirconia/anionic polyacrylamide system-Effects of surfactant presence, solution pH and polymer carboxyl groups content

    Science.gov (United States)

    Wiśniewska, Małgorzata; Chibowski, Stanisław; Urban, Teresa

    2016-05-01

    The adsorption mechanism of anionic polyacrylamide (PAM) on the nanozirconia surface was examined. The effects of solution pH, carboxyl groups content in macromolecules and anionic surfactant (sodium dodecyl sulfate-SDS) addition were determined. The more probable structure of polymer adsorption layer was characterized based on the data obtained from spectrophotometry, viscosimetry and potentiometric titration methods. The adsorbed amount of polymer, size of macromolecules in the solution and surface charge density of ZrO2 particles in the absence and presence of PAM were assessed, respectively. Analysis of these results indicated that the increase of solution pH and content of carboxyl groups in the polymeric chains lead to more expanded conformations of adsorbing macromolecules. As a result, the adsorption of anionic polyacrylamide decreased. The SDS presence caused the significant increase of PAM adsorbed amount at pH 3, whereas at pH 6 and 9 the surfactant addition resulted in reduction of polymer adsorption level.

  4. Study of adsorption properties and inhibition of mild steel corrosion in hydrochloric acid media by water soluble composite poly (vinyl alcohol-o-methoxy aniline)

    OpenAIRE

    R. Karthikaiselvi; S. Subhashini

    2014-01-01

    The efficiency of new water soluble composite namely, poly (vinyl alcohol-o-methoxy aniline) PVAMOA has been studied for corrosion inhibition of mild steel in 1 M hydrochloric acid (HCl). Corrosion inhibition was investigated using weight loss, potentiodynamic polarization and electrochemical impedance studies. The kinetic and thermodynamic parameters for mild steel corrosion and inhibitor adsorption respectively, were determined and discussed. The adsorption of PVAMOA on the mild steel surfa...

  5. Biochar pyrolytically produced from municipal solid wastes for aqueous As(V) removal: adsorption property and its improvement with KOH activation.

    Science.gov (United States)

    Jin, Hongmei; Capareda, Sergio; Chang, Zhizhou; Gao, Jun; Xu, Yueding; Zhang, Jianying

    2014-10-01

    Biochar converted from waste products is being considered as an alternative adsorbent for removal of aqueous heavy metal(loid)s. In this work, experimental and modeling investigations were conducted to examine the effect of biochars pyrolytically produced from municipal solid wastes on removing aqueous As(V) before and after activated by 2M KOH solution. Results showed that the highest adsorption capacity of pristine biochars was 24.49 mg/g. The pseudo-second-order model and Langmuir adsorption isotherm model can preferably describe the adsorption process. The activated biochar showed enhanced As(V) adsorption ability with an adsorption capacity of 30.98 mg/g, which was more than 1.3 times of pristine biochars, and 2-10 times of modified biochars reported by other literatures. Increase of surface area and changes of porous texture, especially the functional groups on the surface of activated biochars are the major contributors to its more efficient adsorption of As(V). PMID:25103038

  6. Adsorption of F2Cdbnd CFCl on TiO2 nano-powder: Structures, energetics and vibrational properties from DRIFT spectroscopy and periodic quantum chemical calculations

    Science.gov (United States)

    Tasinato, Nicola; Moro, Daniele; Stoppa, Paolo; Pietropolli Charmet, Andrea; Toninello, Piero; Giorgianni, Santi

    2015-10-01

    Photodegradation over titanium dioxide (TiO2) is a very appealing technology for removing environmental pollutants from the air, the adsorption interaction being the first step of the whole reaction pathway. In the present work the adsorption of F2Cdbnd CFCl (chlorotrifluoroethene, halon 1113), a compound used by industry and detected in the atmosphere, on a commercial TiO2 nano-powder is investigated experimentally by in situ DRIFT spectroscopy and theoretically through periodic ab initio calculations rooted in DFT. The spectra of the adsorbed molecule suggest that the anchoring to the surface mainly takes place through F atoms. Theoretically, five adsorption configurations for the molecule interacting with the anatase (1 0 1) surface are simulated at B3LYP level and for each of them, structures, binding energies and vibrational frequencies are derived. The interplay between theory and experiments shows the coexistence of different adsorption configurations, the foremost ones featuring the interaction of one F atom with a fivefold coordinated Ti4+ of the surface. These two adsorption models, which mostly differ for the orientation of the adsorbate with respect to the surface, feature a binding energy of -45.6 and -41.0 kJ mol-1 according to dispersion corrected DFT calculations. The favorable adsorption interaction appears as an important requirement toward the application of titanium dioxide technologies for the photocatalytic degradation of halon 1113.

  7. The effect of mixed HCl-KCl competitive adsorbate on Pt adsorption and catalytic properties of Pt-Sn/Al2O3 catalysts in propane dehydrogenation

    Science.gov (United States)

    Zangeneh, Farnaz Tahriri; Taeb, Abbas; Gholivand, Khodayar; Sahebdelfar, Saeed

    2015-12-01

    The effect of competitive adsorbate concentration and combination on the adsorption of H2PtCl6 onto γ-Al2O3 in the preparation and performance of PtSnK/γ-Al2O3 catalyst for propane dehydrogenation was investigated. The catalysts were prepared by sequential impregnation of Sn and Pt precursors. The effect of competitor concentration on Pt adsorption was studied by using hydrochloric acid (0.1-0.3 M) and the effect of pH was studied by using KCl/HCl mixtures at constant (0.1 M) total chloride ion concentration. The catalysts were characterized by nitrogen adsorption/desorption, XRD, XRF, SEM and CO chemisorption. The catalytic performance tests were carried out in a fixed-bed quartz reactor under kinetic controlled condition for proper catalyst screening. It was found that the corrosive competitor HCl could be partially substituted with KCl without appreciable impact on catalyst performance with the advantage of lower acid attack on the support and reduced leaching of the deposited tin. A model based on initial concentration and uptake of the adsorbates was developed to obtain the adsorption parameters. Values of 890 μmol/g and 600 lit/mol were obtained for adsorption site concentration of the tin-impregnated support and equilibrium constant for Pt adsorption, respectively, for HCl concentration range of 0.1-0.3 M.

  8. Surfactant adsorption to soil components and soils.

    Science.gov (United States)

    Ishiguro, Munehide; Koopal, Luuk K

    2016-05-01

    Soils are complex and widely varying mixtures of organic matter and inorganic materials; adsorption of surfactants to soils is therefore related to the soil composition. We first discuss the properties of surfactants, including the critical micelle concentration (CMC) and surfactant adsorption on water/air interfaces, the latter gives an impression of surfactant adsorption to a hydrophobic surface and illustrates the importance of the CMC for the adsorption process. Then attention is paid to the most important types of soil particles: humic and fulvic acids, silica, metal oxides and layered aluminosilicates. Information is provided on their structure, surface properties and primary (proton) charge characteristics, which are all important for surfactant binding. Subsequently, the adsorption of different types of surfactants on these individual soil components is discussed in detail, based on mainly experimental results and considering the specific (chemical) and electrostatic interactions, with hydrophobic attraction as an important component of the specific interactions. Adsorption models that can describe the features semi-quantitatively are briefly discussed. In the last part of the paper some trends of surfactant adsorption on soils are briefly discussed together with some complications that may occur and finally the consequences of surfactant adsorption for soil colloidal stability and permeability are considered. When we seek to understand the fate of surfactants in soil and aqueous environments, the hydrophobicity and charge density of the soil or soil particles, must be considered together with the structure, hydrophobicity and charge of the surfactants, because these factors affect the adsorption. The pH and ionic strength are important parameters with respect to the charge density of the particles. As surfactant adsorption influences soil structure and permeability, insight in surfactant adsorption to soil particles is useful for good soil management. PMID

  9. Synthesis and characterization of a novel Mg–Al hydrotalcite-loaded kaolin clay and its adsorption properties for phosphate in aqueous solution

    Energy Technology Data Exchange (ETDEWEB)

    Deng, Lin, E-mail: denglinlyn@126.com; Shi, Zhou, E-mail: 369329062@qq.com

    2015-07-15

    Highlights: • Kaolin clay was coalesced with Mg–Al hydrotalcite to form composite adsorbent (MKC). • MKC was synthesized through modified co-precipitation method. • MKC gave high adsorption of phosphate over a wide pH range of 2.5–9.5. • MKC is an economical and environmentally friendly adsorbent for phosphate removal and recycling. - Abstract: The mesoporous modified kaolin clay (MKC) was synthesized by loading Mg–Al hydrotalcite onto kaolin clay through coprecipitation method and applied for adsorption of phosphate from aqueous solution. Several techniques, including Brunauer–Emmett–Teller (BET), thermal analysis (TG–DTA), and Fourier transform infrared spectroscopy (FTIR) were employed to characterize the adsorbents. The effects of adsorbent dosage, solution pH, initial phosphate concentration, contact time, temperature, and coexistent anions on phosphate adsorption have been investigated. MKC exhibited a strong uptake affinity to phosphate in a wide pH range of 2.5–9.5, with the maximum adsorptive removal of 98.03%, at adsorbent dosage of 0.2 g/50 mL, pH 7.5, and initial phosphate concentration 25 mg L{sup −1}. The adsorption kinetics followed the pseudo-second-order kinetic model. The Langmuir isothermal model well described the adsorption isotherm data, showing a maximum adsorption capacity for phosphate up to 11.92 mg g{sup −1} at 298 K. The obtained thermodynamic parameters revealed that the adsorption of phosphate onto MKC was an exothermic and spontaneous process. Coexistent chloride, nitrate, and sulfate ions displayed an adverse effect on phosphate adsorption following the order of SO{sub 4}{sup 2−} > NO{sub 3}{sup −} > Cl{sup −}. A mechanism of adsorption that involved (i) electrostatic attraction of hydroxyl groups of the adsorbent with negatively charged phosphate ions, and (ii) anion exchange of NO{sub 3}{sup −} ions that were associated with the surface or interlayer of the adsorbent with anionic phosphate ions in

  10. Adsorption of xylene para- and meta- isomers in NaX and BaX zeolites. Study of properties-structure relations; Adsorption des isomeres para- et meta- du xylene dans les zeolithes NaX et BaX. Etude des relations proprietes-structure

    Energy Technology Data Exchange (ETDEWEB)

    Descours, A.

    1997-02-14

    The separation of para-xylene from C8 aromatics is performed industrially bu adsorption process on zeolitic molecular sieves. The sorption properties of these zeolites are strongly linked to their structure, and their comprehension require an accurate knowledge of the interactions between sorbate molecules and zeolitic structure. The aim of this work is to characterise from a structural point of view the adsorption of para- and meta-xylenes in BaX and NaX zeolites. The former is selective for para-xylene, and the latter has not selective properties for para- and meta-isomers of xylene. For each zeolite, the adsorption of pure para-xylene and meta-xylene or a mixture of the two isomers, is investigated as a function of coverage. Powder neutron diffraction is used to determine the crystalline structure of these zeolites and the different crystallographic adsorption sites of the molecules. The influence of coverage on sorbate-sorbent and sorbate-sorbate interactions is investigated. Infrared spectroscopy allows to determine the chemical environment of the sorbate molecules at low coverage or when the coverage increases, and is particularly effective for the study of the binary mixture of xylenes. This study is performed by sorbing a mixture of xylene isomers, or by sorbing these isomers successively. Infrared studies and crystallographic analysis are compared in order to get a consistent description of adsorption mechanism of xylene isomers for both zeolites as a function of coverage. The role of coverage, of cation type, an the presence of the two xylene isomers is the super-cages is essential. For both zeolites, the increase of coverage actually leads to steric hindrances between sorbed molecules and molecular rearrangements. These reorganizations are connected to the cationic distribution of NaX and BaX zeolites. The sorbed molecules are connected to the cationic distribution of NaX and BaX zeolites. The sorbed molecules are particularly confined in BaX zeolite

  11. Research on phosphorus adsorption properties of sandstone from Chao Lake shore%巢湖湖岸砂石的磷吸附特性研究

    Institute of Scientific and Technical Information of China (English)

    蔡莹; 吴蕾; 陈云峰

    2012-01-01

    The sandstone in Chao Lake shore,which rich in iron,aluminum,manganese and other elements,was used to study the adsorption of phosphorus in water.Results show that there is both physisorption and chemisorption in the adsorption process,and chemisorption is dominant.The adsorption process accords with the quasi secondary dynamic model.The adsorption effect is related with initial phosphorus concentration,and the critical concentration point of phosphorus release and adsorption is about 0.04 mg/L.The phosphorus adsorption generated by sandstone accords with Langmuir isotherm equation,and the maximum absorption capacity is about 1 428.57 mg/kg.The peculiar sandstone is better than ordinary sandstone in phosphorus adsorption,which is economically available.%以巢湖湖岸上富含铁、铝、锰等元素的砂石为实验材料,研究其对水体中磷的吸附效果。实验表明:在砂石对磷的吸附过程中,同时存在着物理吸附和化学吸附,且以化学吸附作用为主,符合准二级动力学模型;砂石对磷的作用与溶液初始磷浓度有关,磷释放与吸附的临界浓度点约为0.04 mg/L;砂石对磷的吸附符合Langmuir等温吸附方程,最大吸附量约为1 428.57 mg/kg,对磷的吸附效果比普通沙石要好,且经济易得。

  12. Insights into the adsorption capacity and breakthrough properties of a synthetic zeolite against a mixture of various sulfur species at low ppb levels.

    Science.gov (United States)

    Vellingiri, Kowsalya; Kim, Ki-Hyun; Kwon, Eilhann E; Deep, Akash; Jo, Sang-Hee; Szulejko, Jan E

    2016-01-15

    The sorptive removal properties of a synthetic A4 zeolite were evaluated against sulfur dioxide (SO2) and four reference reduced sulfur compounds (RSC: hydrogen sulfide (H2S), methanethiol (CH3SH), dimethyl sulfide (DMS, (CH3)2S), and dimethyl disulfide (DMDS, CH3SSCH3). To this end, a sorbent bed of untreated (as-received) A4 zeolite was loaded with gaseous standards at four concentration levels (10-100 part-per-billion (ppb (v/v)) at four different volumes (0.1, 0.2, 0.5, and 1 L increments) in both increasing (IO: 0.1-1.0 L) and decreasing volume order (DO: 1.0 to 0.1 L). Morphological properties were characterized by PXRD, FTIR, and BET analysis. The removal efficiency of SO2 decreased from 100% for all concentrations at 0.1 L (initial sample volume) to ∼82% (100 ppb) or ∼96% (10 ppb) at 3.6 L. In contrast, removal efficiency of RSC was near 100% at small loading volumes but then fell sharply, irrespective of concentration (10-100 ppb) (e.g., 32% (DMS) to 52% (H2S) at 100 ppb). The adsorption capacity of zeolite, if expressed in terms of solid-gas partition coefficient (e.g., similar to the Henry's law constant (mmol kg(-1) Pa(-1))), showed moderate variabilities with the standard concentration levels and S compound types such as the minimum of 2.03 for CH3SH (at 20 ppb) to the maximum of 13.9 for SO2 (at 10 ppb). It clearly demonstrated a notable distinction in the removal efficiency of A4 zeolite among the different S species in a mixture with enhanced removal efficiency of SO2 compared to the RSCs. PMID:26562781

  13. Solvothermal synthesis of MnFe{sub 2}O{sub 4}-graphene composite—Investigation of its adsorption and antimicrobial properties

    Energy Technology Data Exchange (ETDEWEB)

    Chella, Santhosh [Centre for Nanotechnology Research, VIT University, Vellore 632014 (India); Kollu, Pratap, E-mail: pk419@cam.ac.uk [Thin Film Magnetism Group, Cavendish Laboratory, Department of Physics, University of Cambridge, Cambridge CB3 0HE (United Kingdom); Komarala, Eswara Vara P R; Doshi, Sejal [Department of Metallurgical Engineering and Materials Science, Indian Institute of Technology Bombay, Mumbai (India); Saranya, Murugan; Felix, Sathiyanathan; Ramachandran, Rajendran [Centre for Nanotechnology Research, VIT University, Vellore 632014 (India); Saravanan, Padmanapan [Defence Metallurgical Research Laboratory, Hyderabad 5000058 (India); Koneru, Vijaya Lakshmi [Development Alternatives, Qutub Institutional Area, New Delhi 110016 (India); Venugopal, Velmurugan [Centre for Nanotechnology Research, VIT University, Vellore 632014 (India); Jeong, Soon Kwan [Climate Change Technology Research Division, Korea Institute of Energy Research, Yuseong-gu, Daejeon 305-343 (Korea, Republic of); Nirmala Grace, Andrews, E-mail: anirmalagrace@vit.ac.in [Centre for Nanotechnology Research, VIT University, Vellore 632014 (India)

    2015-02-01

    Graphical abstract: - Highlights: • Graphene manganese ferrite composite was synthesized by a solvothermal process. • Adsorption of Pb and Cd metal ions were tested with MnFe{sub 2}O{sub 4}-G material. • The MnFe{sub 2}O{sub 4}-G material showed good adsorption capacity for metal ions. • MnFe{sub 2}O{sub 4}-G showed the higher antibacterial activity of 82%, than graphene. - Abstract: Graphene manganese ferrite (MnFe{sub 2}O{sub 4}-G) composite was prepared by a solvothermal process. The as-prepared graphene manganese ferrite composite was tested for the adsorption of lead (Pb(II)) and cadmium (Cd(II)) ions by analytical methods under diverse experimental parameters. With respect to contact time measurements, the adsorption of Pb and Cd ions increased and reached equilibrium within 120 and 180 min at 37 °C with a maximum adsorption at pH 5 and 7 respectively. The Langmuir model correlates to the experimental data showing an adsorption capacity of 100 for Pb(II) and 76.90 mg g{sup −1} for Cd(II) ions. Thermodynamic studies revealed that the adsorption of Pb and Cd ions onto MnFe{sub 2}O{sub 4}-G was spontaneous, exothermic and feasible in the range of 27–47 °C. Cytotoxicity behavior of graphene against bacterial cell membrane is well known. To better understand its antimicrobial mechanism, the antibacterial activity of graphene and MnFe{sub 2}O{sub 4}-G nanocomposite was compared. Under similar concentration and incubation conditions, nanocomposite MnFe{sub 2}O{sub 4}-G dispersion showed the highest antibacterial activity of 82%, as compared to graphene showing 37% cell loss. Results showed that the prepared composite possess good adsorption efficiency and thus could be considered as an excellent material for removal of toxic heavy metal ions as explained by adsorption isotherm. Hence MnFe{sub 2}O{sub 4}-G can be used as an adsorbent as well as an antimicrobial agent.

  14. Modification of polyetherurethane for biomedical application by radiation induced grafting. II. Water sorption, surface properties, and protein adsorption of grafted films

    International Nuclear Information System (INIS)

    A series of polyetherurethane films grafted by means of gamma radiation with hydrophilic or reactive monomers (2-hydroxyethyl methacrylate, 2,3-epoxypropyl methacrylate, 2,3-dihydroxypropyl methacrylate, and acrylamide) and partially chemically modified were subjected to various physico-chemical investigation methods involving water sorption, contact angle, and protein adsorption measurements. From contact angle data the interfacial free energy gamma sw between grafted films and water was calculated. It was found that the water uptake of grafted films increases with grafting yield or, in the case of grafted and afterwards chemically modified films, with reaction yield; the diffusion coefficient of water in the modified films also increases with grafting yield. Contact angle studies revealed all grafted films to have surfaces more hydrophilic than the ungrafted trunk polymer. The degree of hydrophilicity--especially of HEMA-grafted films--strongly depends on grafting conditions. For some grafted samples with high surface hydrophilicity very low interfacial free energies approaching zero were measured. The study of the competitive adsorption of bovine serum albumin, gamma-globulin, and fibrinogen from a synthetic protein solution onto modified films showed that the adsorption of albumin increases markedly with increasing grafting yields, whereas the fibrinogen and gamma-globulin adsorption only slightly increases. A correlation between interfacial free energy and protein adsorption in the sense of the minimum interfacial free energy hypothesis was found only for samples with grafting yields below 5%. At higher grafting yields the increased surface area complicates the analysis

  15. Study on the oxygen adsorption property of nitrogen-containing metal-free carbon-based cathode catalysts for oxygen reduction reaction

    International Nuclear Information System (INIS)

    We study the characteristics of oxygen adsorption on metal-free carbon-based cathode catalysts derived from nitrogen-containing polyamide (PA) and nitrogen-free phenolic resin (PhRs). Electrochemical analysis and Raman spectroscopy showed higher 2-electron oxygen reduction reaction (ORR) activity and more defect sites in PA than PhRs. The increase in the amount of adsorbed oxygen in PA was also identified by oxygen adsorption isotherms. In situ X-ray photoelectron spectroscopy revealed that graphite-like nitrogen contributes to oxygen adsorption and C=O components are dominant in PA. These experimental results indicate that the adsorbed C=O components near the graphite-like nitrogen can be assigned as active sites for 2-electron ORR.

  16. Ab Initio Calculations of the Electronic Properties of Polypyridine Transition Metal Complexes and Their Adsorption on Metal Surfaces in the Presence of Solvent and Counterions

    DEFF Research Database (Denmark)

    Jónsson, E. Ö.; Thygesen, Kristian Sommer; Ulstrup, Jens;

    2011-01-01

    Os(II)/(III) and Co(II)/(III) polypyridine complexes in aqueous solution are robust molecular entities both in freely solute state and adsorbed on Au(111)- and Pt(111)-electrode surfaces. This class of robust coordination chemical compounds have recently been characterized by electrochemical...... structure of the complexes in the presence of the solvent, are conserved upon adsorption, whereas the structural features of the different oxidation states are completely lost upon adsorption under vacuum conditions. Detailed microscopic insight such as offered by the present study will be important in...

  17. Investigation of radiotracer adsorption

    International Nuclear Information System (INIS)

    Results of laboratory investigation of adsorption of radiotracers in several soil materials are presented. Compounds were chosen which are applied in hydrogeology for tracer determination of underground water flow parameters. Adsorption values were measured as functions of the following parameters: solution concentration, adsorption duration, concentration of hydrogen ions and ion strength of the solution. The most interesting results are: a linear dependence of adsorption on the solution concentration (observed in a wide range of concentrations), and an extended period (several tens of minutes) necessary for the adsorption system to achieve a state approaching dynamic equilibrium. (author)

  18. Adsorption and inhibitive properties of a new heterocyclic furan Schiff base on corrosion of copper in HCl 1 M: Experimental and theoretical investigation

    Energy Technology Data Exchange (ETDEWEB)

    Issaadi, S., E-mail: issaadi-s@univ-setif.dz; Douadi, T.; Chafaa, S.

    2014-10-15

    Highlights: • The new Schiff base is a good corrosion inhibitor for copper in 1 M HCl. • SEM and FT-IR analysis indicates that copper corrosion can be inhibited due to the adsorption of Schiff base on copper surface. • Quantum chemical calculations reveal O and N atoms are proper adsorption sites. - Abstract: A new corrosion inhibitor namely (NE)-N-(furan-2-ylmethylidene)-4-({4-[E)-(furan-2-ylmethylidene) amino] phenyl} ethyl) aniline (SB)has been synthesized and its influence on corrosion inhibition of copper in 1 M hydrochloric acid solution has been studied by both electrochemical impedance spectroscopy (EIS) and Tafel polarization measurements. The investigated inhibitor has shown good inhibition efficiency in 1 M HCl. Adsorption of SB on copper surface follows the Langmuir isotherm. Copper surface characterization was performed using scanning electron microscopy (SEM) and Fourier transform infrared spectroscopy (FT-IR). Quantum chemical calculations show that SB has large negative charge in nitrogen and oxygen atoms, which facilitates the adsorption of SB on the copper surface.

  19. Emulsifying properties and oil/water (O/W) interface adsorption behavior of heated soy proteins: effects of heating concentration, homogenizer rotating speed, and salt addition level.

    Science.gov (United States)

    Cui, Zhumei; Chen, Yeming; Kong, Xiangzhen; Zhang, Caimeng; Hua, Yufei

    2014-02-19

    The adsorption of heat-denatured soy proteins at the oil/water (O/W) interface during emulsification was studied. Protein samples were prepared by heating protein solutions at concentrations of 1-5% (w/v) and were then diluted to 0.3% (w/v). The results showed that soy proteins that had been heated at higher concentrations generated smaller droplet size of emulsion. Increase in homogenizer rotating speed resulted in higher protein adsorption percentages and lower surface loads at the O/W interface. Surface loads for both unheated and heated soy proteins were linearly correlated with the unadsorbed proteins' equilibrium concentration at various rotating speeds. With the rise in NaCl addition level, protein adsorption percentage and surface loads of emulsions increased, whereas lower droplet sizes were obtained at the ionic strength of 0.1 M. The aggregates and non-aggregates displayed different adsorption behaviors when rotating speed or NaCl concentration was varied. PMID:24460091

  20. Adsorption of molecular hydrogen on nanostructered surfaces

    International Nuclear Information System (INIS)

    Were investigated the effect of the structural characteristics of model nanoporous environments on the adsorption of molecular hydrogen. The adsorption properties of the target nanostructures (graphene and ZnO sheets, carbon foams, metal-organic frameworks) are evaluated in a broad range of thermodynamic conditions. The study is carried out within the density functional theory for quantum fluids at finite temperature (QLDFT), which allows to account for the many-body and quantum delocalization effects in a single theoretical framework. The exchange-correlation (excess) functional is derived from the empirical equation of state of the homogeneous system. We focus on the evaluation of hydrogen storage capacities of the substrates and on the emergence of quantum effects triggered by the confinement imposed by the host structure. The approach provides accurate estimates of the hydrogen storage capacities for realistic adsorptive media. The relation between the microscopic structure of the hydrogen fluid and the calculated adsorption properties is also addressed. (full text)

  1. Thiol-functionalized Fe3O4/SiO2 microspheres with superparamagnetism and their adsorption properties for Au(III) ion separation

    Science.gov (United States)

    Peng, Xiangqian; Zhang, Wei; Gai, Ligang; Jiang, Haihui; Tian, Yan

    2016-08-01

    Thiol-functionalized Fe3O4/SiO2 microspheres (Fe3O4/SiO2-SH) with high saturation magnetization (69.3 emu g-1), superparamagnetism, and good dispersibility have been prepared by an ethylene glycol reduction method in combination with a modified Stöber method. The as-prepared composite magnetic spheres are characterized with fourier transform infrared spectroscopy (FT-IR), zeta potential, X-ray powder diffraction (XRD), transmission electron microscopy (TEM), and superconducting quantum interference magnetometer, and tested in separation of Au(III) ions from aqueous solutions. The data for Au(III) adsorption on Fe3O4/SiO2-SH are analyzed with the Langmuir, Freundlich, Temkin, and Dubinin-Radushkevich isotherm models, and the pseudo-first-order, pseudo-second-order, and intraparticle diffusion kinetics models. The adsorption behaviors of Au(III) on Fe3O4/SiO2-SH follow the Langmuir isotherm model, and the adsorption process conforms to the pseudo-second-order kinetic model. The maximum adsorption capacity of Au(III) on Fe3O4/SiO2-SH is 43.7 mg g-1. Acetate anions play an important role yet Cu(II) ions have little interference in the adsorption of Au(III) on the adsorbent. A satisfactory recovery percentage of 89.5% is acquired by using an eluent with 1 M thiourea and 5% HCl, although thiols have a high affinity to Au(III) ions based on the hard-soft acid-base (HSAB) theory by Pearson.

  2. 套种不同牧草的果园土壤对铵的吸附特性研究%Study on the Ammonia Nitrogen Adsorption Properties of Orchard Soil Interplanted with Different Forages

    Institute of Scientific and Technical Information of China (English)

    郑涛; 李发林; 黄炎和; 郑域茹; 林阳春; 林晓兰; 武英; 谢南松

    2012-01-01

    以套种不同牧草的果园土壤为研究对象,通过室内等温吸附实验,分析比较了各个处理对氨态氮的吸附特性,并将结果用不同的数学模型拟合进行分析.结果表明:当土壤的氨浓度超过一临界值时,其对氨离子的吸附量会出现明显上升,而在此临界值以下则变化不明显;套种不同牧草可不同程度地提高土壤的铵吸附能力,具体表现为圆叶决明>百喜草>平托花生>宽叶雀稗>CK(自然生日本草);各处理土壤铵等温吸附与多项式拟合效果最佳,与Freundlich、Temkin方程拟合达显著水平,Langmuir方程的拟合结果较差.%The orchard soil interplanted with different forages was used in the indoor isothermal adsorption experiment, and the ammonia nitrogen adsorption properties of different trentments were analyzed and compared with mathematical models. It showed that the adsorption of ammonia ion in soil would be increased obviously when the ammonium concentration was over the critical value, while that would not change significantly when the ammonium concentration was lower than the critical value. Intercropped different forages could improve the ammonia nitrogen adsorption properties, contributing in the following order: Chamaecrista Rotundifolia>Paspalujn notatum Flugge>Arachis pintoi>Pspalum Wettsteinii>CK.. The isothermal adsorption of different trentments had the best simulating effect with the polynomial, the simulating effect with Freundilch and Temkin reached significant level, and the simulating effect with Langmuir was poor.

  3. Study on adsorption properties of H103 macroreticular resin to phenol%H103大孔树脂吸附苯酚性能研究

    Institute of Scientific and Technical Information of China (English)

    许敏; 张林生

    2011-01-01

    The static adsorption experiment of phenol by H103,a macroreticular resin,was carried out under different conditions.The results showed that macroreticular resin for adsorption of phenol from aqueous solution adsorbed very quickly within 60 min and reached basic balance.With the mass concentration increasing the static adsorption capability for adsorption of phenol by macroreicular resin increased.The adsorption data could be well fitted by the Freundlich adsorption isotherm model.Dynamic treating of a fine chemical wastewater containing phenol was investigated.Results showed that the removal efficiency of phenol and COD in wastewater was near 91.9% and ≥ 69.3%,respectively,at room temprature and a fix-bed flow rate of 3 BV/h.When the saturated resin regenerated by 5% NaOH solution,the phenol regeneration rate can reach 86.5%,which achieved the recovery of phenol effectively.%通过静态吸附实验,研究了不同条件下H103大孔树脂对水中苯酚的吸附性能。结果表明,树脂对水中苯酚的吸附速率较快,60 min内基本达到平衡。树脂对水中苯酚的吸附量随其初始浓度的增加而增加,并呈线性关系。吸附数据采用Freundlich吸附等温线模型拟合结果较好。动态处理某精细化工含酚废水结果表明,室温下固定床流速为3 BV/h时,废水中苯酚去除率接近91.9%,COD去除率≥69.3%。饱和树脂采用5%NaOH溶液再生,苯酚再生率为86.5%,有效实现了酚的回收。

  4. Surface-complexation modeling of radionuclide adsorption in subsurface environments

    International Nuclear Information System (INIS)

    Requirements for applying the surface-complexation modeling approach to simulating radionuclide adsorption onto geologic materials are discussed. Accurate description of adsorption behavior requires that chemical properties of both adsorbent and adsorbate be characterized in conjunction with determinations of extent of adsorption. Critical chemical properties of adsorbents include dissolution and oxidation/reduction behavior, types and densities of adsorption sites, and interaction of sites with solution components. Important adsorbate properties include hydrolysis, complexation, oxidation/reduction, and oligomerization. Adsorption behavior is described by a set of chemical reactions and binding constants between: adsorption sites and solution components, adsorbate and solution components, and adsorbate and adsorption sites. Methods for implementing such an approach are discussed;examples based on solute adsorption onto oxides are presented. The approach currently used to simulate sorption onto geologic materials, i.e., the determination of distribution coefficients, yields estimates that are disparate and subject to large errors. Implementation of the surface-complexation modeling approach would greatly improve the predictability of the role of adsorption in regulating radionuclide transport in subsurface environments. Research efforts should be directed towards understanding radionuclide adsorption onto fixed-charge minerals (e.g., clays), carbonate minerals, and poly-mineralic assemblages representative of those present at potential repositories. 123 refs., 19 figs., 18 tabs

  5. The Adsorption Mechanism of Modified Activated Carbon on Phenol

    Directory of Open Access Journals (Sweden)

    Lin J. Q.

    2016-01-01

    Full Text Available Modified activated carbon was prepared by thermal treatment at high temperature under nitrogen flow. The surface properties of the activated carbon were characterized by Boehm titration, BET and point of zero charge determination. The adsorption mechanism of phenol on modified activated carbon was explained and the adsorption capacity of modified activated carbon for phenol when compared to plain activated carbon was evaluated through the analysis of adsorption isotherms, thermodynamic and kinetic properties. Results shows that after modification the surface alkaline property and pHpzc value of the activated carbon increase and the surface oxygen-containing functional groups decrease. The adsorption processes of the plain and modified carbon fit with Langmuir isotherm equation well, and the maximum adsorption capacity increase from 123.46, 111.11, 103.09mg/g to 192.31, 178.57, 163,93mg/g under 15, 25 and 35°C after modification, respectively. Thermodynamic parameters show that the adsorption of phenol on activated carbon is a spontaneously exothermic process of entropy reduction, implying that the adsorption is a physical adsorption. The adsorption of phenol on activated carbon follows the pseudo-second-order kinetics (R2>0.99. The optimum pH of adsorption is 6~8.

  6. Study on the adsorption properties of O3, SO2, and SO3 on B-doped graphene using DFT calculations

    Science.gov (United States)

    Rad, Ali Shokuhi; Shabestari, Sahand Sadeghi; Mohseni, Soheil; Aghouzi, Samaneh Alijantabar

    2016-05-01

    We investigated the structure, adsorption, electronic states, and charge transfer of O3, SO2 and SO3 molecules on the surface of a B-doped graphene using density functional theory (DFT). We found weak physisorption of SO2 (-10.9 kJ/mole, using B3LYP-D) and SO3 (-15.7 kJ/mole, using B3LYP-D) on the surface of B-doped graphene while there is strong chemisorption for O3 (-96.3 kJ/mole, using B3LYP-D) on this surface. Our results suggest the potential of B-doped graphene as a selective sensor/adsorbent for O3 molecule. We noticed some change in hybridizing of boron from sp2 to sp3 upon adsorption of O3 which cases transformation of the adsorbent from 2D to 3D.

  7. Adsorption of light alkanes on coconut nanoporous activated carbon

    Directory of Open Access Journals (Sweden)

    K. S. Walton

    2006-12-01

    Full Text Available This paper presents experimental results for adsorption equilibrium of methane, ethane, and butane on nanoporous activated carbon obtained from coconut shells. The adsorption data were obtained gravimetrically at temperatures between 260 and 300K and pressures up to 1 bar. The Toth isotherm was used to correlate the data, showing good agreement with measured values. Low-coverage equilibrium constants were estimated using virial plots. Heats of adsorption at different loadings were also estimated from the equilibrium data. Adsorption properties for this material are compared to the same properties for BPL activated carbon and BAX activated carbon.

  8. A comparative study of size-controlled worm-like amylopectin nanoparticles and spherical amylose nanoparticles: Their characteristics and the adsorption properties of polyphenols.

    Science.gov (United States)

    Qiu, Chao; Qin, Yang; Zhang, Shuangling; Xiong, Liu; Sun, Qingjie

    2016-12-15

    Polyphenols are known to have potent antioxidant capacity and other health-beneficial bioactivities. However, extremely low absorption rate of polyphenols restricts their bioactivity in vivo. Development of biopolymer nanoparticle carrier is a promising solution. For the first time, we have successfully prepared worm-like amylopectin nanoparticles (APNPs) and spherical amylose nanoparticles (AMNPs) using fractionated amylose and amylopectin from potato starch. Additionally, adsorption kinetics and adsorption isotherms of three polyphenols (procyanidins, epicatechins and catechins) on AMNPs and APNPs were investigated. We found that procyanidins, epicatechins, and catechins could bind to AMNPs at levels of up to 1.2, 1.5, and 1.4g/g, respectively, while the APNPs demonstrated higher adsorption amounts of 1.4, 4.3, and 2.2g/g, respectively. Furthermore, the particle size of polyphenol-loaded nanoparticles was not significantly changed. The results suggested that APNPs and AMNPs can be applied as an effective nanocarrier by delivering active compounds for nutraceutical and pharmaceutical industries. PMID:27451221

  9. Determination of adsorptive and catalytic properties of copper, silver and iron contain titanium-pillared bentonite for the removal bisphenol A from aqueous solution

    Science.gov (United States)

    Tomul, Fatma; Turgut Basoglu, Funda; Canbay, Hale

    2016-01-01

    Ti-pillared bentonite, Cu, Ag and Fe modified Ti-pillared bentonite and Cu/Ti- and Fe/Ti-mixed pillared bentonite were synthesized using different titanium sources by direct synthesis or by modification after synthesis. The effects of synthesis conditions on the surface characteristics, pore structure and acidity of the pillared bentonites were investigated by SEM-EDS, XPS, XRD, N2-adsorption/desorption and FTIR analyses before and after ammonia adsorption. The results of EDS, XPS and XRD analysis confirmed that titanium, copper, silver and iron were incorporated into the bentonite structure. In the XRD patterns, the formation of delaminated structure reflecting the non-parallel distribution of the bentonite layers by pillaring with Ti, Cu/Ti and Fe/Ti-pillars was observed. XPS spectra indicated the presence of TiO2, CuO, Ag and Ag2O and Fe2O3 species depending on the source of active metals in the synthesized samples. In the FTIR spectra, an increase in the Bronsted/Lewis peak intensity was observed with the loading of copper and iron, whereas a decrease in Lewis and Bronsted acidities was observed with incorporation of silver. Adsorption studies indicated that the adsorption capacity of the sample synthesized using titanium (IV) propoxide and incorporating iron to the structure by ion exchange (Fe-PTi-PILC) were higher than those in other samples. The adsorption of BPA (bisphenol A) by all tested samples was found to fit the Langmuir isotherm. In the catalytic wet peroxide oxidation (CWPO) over PTi-PILC (prepared by titanium (IV) propoxide), Fe-PTi-PILC and Cu-PTi-PILC (prepared by copper impregnated Ti-pillared bentonite) samples, BPA values close to complete conversion were achieved within 30 min at 25 °C, pH 4 and 5 g/L mcat. CWPO results showed that increasement of pH causes a decrease the rate of oxidation. On the other hand, by the time catalyst and BPA concentration is increased, the rate of oxidation is increased as well.

  10. Mapping the Surface Adsorption Forces of Nanomaterials in Biological Systems

    Science.gov (United States)

    Xia, Xin R.; Monteiro-Riviere, Nancy A.; Mathur, Sanjay; Song, Xuefeng; Xiao, Lisong; Oldenberg, Steven J.; Fadeel, Bengt; Riviere, Jim E.

    2011-01-01

    The biological surface adsorption index (BSAI) is a novel approach to characterize surface adsorption energy of nanomaterials that is the primary force behind nanoparticle aggregation, protein corona formation, and other complex interactions of nanomaterials within biological systems. Five quantitative nanodescriptors were obtained to represent the surface adsorption forces (hydrophobicity, hydrogen bond, polarity/polarizability, and lone-pair electrons) of the nanomaterial interaction with biological components. We have mapped the surface adsorption forces over 16 different nanomaterials. When the five-dimensional information of the nanodescriptors was reduced to two dimensions, the 16 nanomaterials were classified into distinct clusters according their surface adsorption properties. BSAI nanodescriptors are intrinsic properties of nanomaterials useful for quantitative structure–activity relationship (QSAR) model development. This is the first success in quantitative characterization of the surface adsorption forces of nanomaterials in biological conditions, which could open a quantitative avenue in predictive nanomedicine development, risk assessment, and safety evaluation of nanomaterials. PMID:21999618

  11. Adsorption of polar, nonpolar, and substituted aromatics to colloidal graphene oxide nanoparticles

    NARCIS (Netherlands)

    Wang, Fang; Haftka, Joris J H; Sinnige, Theo L.; Hermens, Joop L M; Chen, Wei

    2014-01-01

    We conducted batch adsorption experiments to understand the adsorptive properties of colloidal graphene oxide nanoparticles (GONPs) for a range of environmentally relevant aromatics and substituted aromatics, including model nonpolar compounds (pyrene, phenanthrene, naphthalene, and 1,3-dichlorobenz

  12. Stability characteristics and structural properties of single- and double-walled boron-nitride nanotubes under physical adsorption of Flavin mononucleotide (FMN) in aqueous environment using molecular dynamics simulations

    Science.gov (United States)

    Ansari, R.; Ajori, S.; Ameri, A.

    2016-03-01

    The non-cytotoxic properties of Boron-nitride nanotubes (BNNTs) and the ability of stable interaction with biomolecules make them so promising for biological applications. In this research, molecular dynamics (MD) simulations are performed to investigate the structural properties and stability characteristics of single- and double-walled BNNTs under physical adsorption of Flavin mononucleotide (FMN) in vacuum and aqueous environments. According to the simulation results, gyration radius increases by rising the weight percentage of FMN. Also, the results demonstrate that critical buckling force of functionalized BNNTs increases in vacuum. Moreover, it is observed that by increasing the weight percentage of FMN, critical force of functionalized BNNTs rises. By contrast, critical strain reduces by functionalization of BNNTs in vacuum. Considering the aqueous environment, it is observed that gyration radius and critical buckling force of functionalized BNNTs increase more considerably than those of functionalized BNNTs in vacuum, whereas the critical strains approximately remain unchanged.

  13. Synthesis and adsorption properties of Pb2+ chromogenic imprinted adsorbent%铅离子显色印迹吸附剂的制备及其吸附性能

    Institute of Scientific and Technical Information of China (English)

    程文霞; 刘成伦; 谢太平

    2013-01-01

    以pb2+为模版分子,在硅胶表面接枝双硫腙,利用溶胶-凝胶法合成一种pb2+显色印迹吸附剂(MIPs).采用红外(IR)和扫描电镜(SEM)对MIPs进行了表征.通过平衡吸附实验,研究了MIPs的吸附性能、显色性能和其对pb2+的选择识别性能.结果表明,双硫腙通过与硅胶形成氢键而接枝在硅胶表面;MIPs对pb2+的显色限为10μmol/L;在Cd2+存在的条件下,其对pb2+的相对选择系数为250;MIPs对pb2+的吸附可以用Langmiur等温吸附方程来拟合,吸附焓变为66.054kJ/mol.制备的MIPs在5min内吸附率可以达到97%,可以用于含铅废水中pb2+的分离和测定.%A new type of Pb2+ chromogenic imprinted adsorbent was prepared by sol-gel approach with Pb2+ as the template and dithizone grafting onto the silica gel surface. The adsorbent was characterized by FT-IR and scanning electron microscopy. The adsorption property, chromogenic property and selective recognition ability of the adsorbent were studied by equilibrium-adsorption method. Results showed that the dithizone was coated on the silica gel through hydrogen bond. The chromogenic limit of the printed adsorbent was 10μmol/L,the relative selectivity coefficient was 250 while Cd2+ existed; the extraction behavior of the Pb2+ was conformed by Langmuir's equation and the enthalpy of adsorption was 66. 054kJ/mol. The adsorption capacity reached 97% in 5 min and it could be used for separation and determination of trace Pb2+ in the waste water.

  14. Adsorption studies on cellulose surfaces by combinations of interfacial techniques

    OpenAIRE

    Eronen, Paula

    2011-01-01

    In this work, the adsorption of various polymers on cellulose surfaces was studied in detail at molecular level. Special attention was paid on the interactions between renewable polysaccharides and different nanofibrillated cellulose (NFC) grades. Polymer or nanoparticle adsorption in aqueous medium was explored as a strategy to functionalize NFC. The role of pulp raw material and chemical pre-treatment on the NFC properties was clarified via indirect adsorption studies with ultrathin NFC fil...

  15. Mechanisms of Ions Adsorption by Nanodiamonds in Aqueous Suspensions

    Directory of Open Access Journals (Sweden)

    K.A. Laptinskiy

    2013-12-01

    Full Text Available This work is devoted to the study of adsorption properties and adsorption mechanisms of the original (I6, modified (I6COOH nanodiamonds and charcoal dispersed in water, with respect to dissolved ions (Cu2 +, Pb2 +, NO3 –, CH3COO – using optical spectroscopy methods: Raman and IR spectroscopies, absorption, dynamic light scattering. Mechanisms of anions and cations adsorption were studied.

  16. Characterization of zeolite-based coatings for adsorption heat pumps

    CERN Document Server

    Freni, Angelo; Bonaccorsi, Lucio; Chmielewski, Stefanie; Frazzica, Andrea; Calabrese, Luigi; Restuccia, Giovanni

    2015-01-01

    This book proposes a radically new approach for characterizing thermophysical and mechanical properties of zeolite-based adsorbent coatings for Adsorptive Heat Transformers (AHT). It presents a developed standard protocol for the complete characterization of advanced coated adsorbers. Providing an in-depth analysis of the different procedures necessary for evaluating the performance of adsorbers, it also presents an analysis of their stability under the hydrothermal and mechanical stresses during their entire life cycle. Adsorptive Heat Transformers (AHT), especially adsorption chillers and

  17. A Simple Adsorption Experiment

    Science.gov (United States)

    Guirado, Gonzalo; Ayllon, Jose A.

    2011-01-01

    The study of adsorption phenomenon is one of the most relevant and traditional physical chemistry experiments performed by chemistry undergraduate students in laboratory courses. In this article, we describe an easy, inexpensive, and straightforward way to experimentally determine adsorption isotherms using pieces of filter paper as the adsorbent…

  18. Effect of pendant isophthalic acid moieties on the adsorption properties of light hydrocarbons in HKUST-1-like tbo -MOFs: Application to methane purification and storage

    KAUST Repository

    Belmabkhout, Youssef

    2014-01-01

    Equilibrium adsorption of methane (CH4), C2+ gases (ethane (C2H6), ethylene (C2H4), propane (C3H8), and propylene (C3H6)), and carbon dioxide (CO2) was measured on a series of tbo-MOFs (topological analogues of the prototypical MOF, HKUST-1, correspondingly dubbed tbo-MOF-1), which were developed via the supermolecular building layer (SBL) pillaring strategy. Specifically, tbo-MOF-2 and its isoreticular, functionalized analogue, tbo-MOF-2-{CH2O[Ph(CO2H)2]}2 (or tbo-MOF-3), which is characterized by pendant isophthalic acid moieties freely pointing into the cavities, were evaluated on the basis of potential use in methane storage and C2+/CH4 separation. The parent, tbo-MOF-2, showed high gravimetric and volumetric CH4 uptake, close to the U.S. Department of Energy (DOE) target for methane storage at 35 bar and room temperature. Though the presence of the pendant isophthalic acid moiety in the analogous compound, tbo-MOF-3, led to a decrease in total CH4 uptake, due mainly to the reduced size of the cavities, interestingly, it increased the affinity of the SBL-based tbo-MOF platform for propane, propene, ethane, and ethylene at low pressures compared with CH4, due additionally to the enhanced interactions of the highly polarizable light hydrocarbons with the isophthalic acid moiety. Using Ideal Adsorption Solution Theory (IAST), the predicted mixture adsorption equilibria for the C3H8/CH4, C3H6/CH4, C2H6/CH4, C2H4/CH4, and C3H8/CO2 systems showed high adsorption selectivity for C2+ over methane for tbo-MOF-3 compared with tbo-MOF-2. The high working storage capacity of tbo-MOF-2 and the high affinity of tbo-MOF-3 for C2+ over CH4 and CO2 make tbo-MOF an ideal platform for studies in gas storage and separation.

  19. A theoretical study of nitric oxide adsorption and dissociation on copper-exchanged zeolites SSZ-13 and SAPO-34: the impact of framework acid-base properties.

    Science.gov (United States)

    Uzunova, Ellie L; Mikosch, Hans

    2016-04-20

    The adsorption of nitric oxide as dinitrosyls and the deNOx proton-mediated reaction mechanism are assessed using electronic structure methods and transition state theory. Dinitrosyls bind to copper cations either via a N-atom or via an O-atom, with N-binding being more stable. In their ground states, dinitrosyls reach a planar configuration with the metal cation. The two nitric oxide molecules are kept together in O-bonded dinitrosyls by the N-N bond and the adsorption complex obtains a cyclic planar structure, while N-bonded dinitrosyls have out-of-plane conformations with low energy barriers. An asymmetric structure ZCu(ON)(NO) with one N-bonded nitrosyl and the other O-bonded is of the lowest stability. The cyclic hyponitrite ZCu(ON)2 adsorption complex undergoes O-N bond breaking upon protonation of one oxygen atom and this lowers the energy barrier of the first reaction step of nitric oxide dissociation to yield N2O and a hydroxylated copper site ZCu(OH) by 45 kJ mol(-1) for Cu-SAPO-34 and by 46 kJ mol(-1) for Cu-SSZ-13. The more stable N-bonded dinitrosyl ZCu(NO)2 provides less favorable reaction which passes through the asymmetric ZCu(ON)(NO) intermediate structure. Brønsted acid sites facilitate the reversal of one nitrosyl group. The role of proton transfer from a Brønsted acid site to dinitrosyls is not limited to the initial step of facilitating the N-O bond cleavage, but it also contributes to the stabilization of intermediate oxygen species formed at the copper site as hydroxide ZCu(OH) and hydroperoxide, ZCuOOH. Without protonation, the unstable ZCuO intermediate causes structural deformation with strongly lengthened T-O bonds in the framework. The rate determining step is N2O decomposition to N2 and O2, whether starting with a ZCu(NO)2 or a ZCu(ON)2 adsorption complex, and Cu-SSZ-13 has a clear advantage with an energy barrier of 195 kJ mol(-1)vs. 265 kJ mol(-1) for Cu-SAPO-34. In the final step the Brønsted acid site is restored by proton

  20. NO adsorption studies on silicene nanosheet: DFT investigation

    Energy Technology Data Exchange (ETDEWEB)

    Chandiramouli, R., E-mail: rcmoulii@gmail.com [School of Electrical & Electronics Engineering, SASTRA University, Tirumalaisamudram, Thanjavur 613 401 (India); Srivastava, Anurag [Advanced Materials Research Group, Computational Nanoscience & Technology Laboratory, ABV-Indian Institute of Information Technology & Management Gwalior (M.P.), Gwalior 474 015 (India); Nagarajan, V. [School of Electrical & Electronics Engineering, SASTRA University, Tirumalaisamudram, Thanjavur 613 401 (India)

    2015-10-01

    Graphical abstract: - Highlights: • The adsorption characteristics of NO on silicene nanosheets are studied using density functional theory. • The NO adsorption characteristics are studied in pristine, Al and P substituted silicene nanosheet. • NO adsorption properties depend on adsorbed energy, HOMO-LUMO gap and Mulliken charge transfer. • The substitution of P atoms in silicene nanosheet enhances the NO adsorption properties. - Abstract: The electronic properties, structural stability and nitric oxide (NO) adsorption characteristics on pristine, Al and P substituted silicene nanosheet are studied using density functional theory with B3LYP/LanL2DZ basis set. The structural stability of silicene nanostructure is discussed in terms of formation energy. The formation energy, dipole moment, point symmetry, ionization potential and electron affinity of silicene nanosheet are reported. The adsorption characteristics of NO on silicene nanosheet are explored in terms of adsorption energy, energy gap and Mulliken charge transfer. The favorable adsorption site of NO on silicene nanosheet is identified and reported. From the observations, it is inferred that the adsorption characteristics of NO are prominent on pristine and P substituted silicene nanosheet.

  1. NO adsorption studies on silicene nanosheet: DFT investigation

    International Nuclear Information System (INIS)

    Graphical abstract: - Highlights: • The adsorption characteristics of NO on silicene nanosheets are studied using density functional theory. • The NO adsorption characteristics are studied in pristine, Al and P substituted silicene nanosheet. • NO adsorption properties depend on adsorbed energy, HOMO-LUMO gap and Mulliken charge transfer. • The substitution of P atoms in silicene nanosheet enhances the NO adsorption properties. - Abstract: The electronic properties, structural stability and nitric oxide (NO) adsorption characteristics on pristine, Al and P substituted silicene nanosheet are studied using density functional theory with B3LYP/LanL2DZ basis set. The structural stability of silicene nanostructure is discussed in terms of formation energy. The formation energy, dipole moment, point symmetry, ionization potential and electron affinity of silicene nanosheet are reported. The adsorption characteristics of NO on silicene nanosheet are explored in terms of adsorption energy, energy gap and Mulliken charge transfer. The favorable adsorption site of NO on silicene nanosheet is identified and reported. From the observations, it is inferred that the adsorption characteristics of NO are prominent on pristine and P substituted silicene nanosheet

  2. Adsorption of single-strand alkylammonium salts on bentonite, surface properties of the modified clay and polymer nanocomposites formation by a two-roll mill

    International Nuclear Information System (INIS)

    The adsorption of tallow alkylammonium salts onto bentonite from the Lopburi province in Thailand, and the effect of surface wettability on the formation of polymer-clay nanocomposites are reported. We looked specifically at octadecyltrimethyl ammonium chloride (S18), a popular member of the tallow alkylammonium salt family. The adsorption of S18 onto the bentonite interlayer can be divided into three distinct stages depending upon the initial concentration of S18. These stages are (a) monolayer formation, (b) intermediate state of double layer formation and (c) double layer formation. A decrease in surface energy driven by drops in the values of the polar and dispersive components was observed as the amount of surfactant surface coverage increased. Using thermal gravimetric analysis (TGA), the critical surface energy (CSE) of organoclay was found to decrease as the amount of absorbed S18 increased. S18 organoclay with different degrees of surface coverage was used in a two-roll mill to prepare high-density polyetheylene (HDPE)-clay nanocomposites. The oxidized polyethylene wax (OWax) was used as a dispersing agent to promote the delamination of the organoclay platelets. The results from X-ray diffraction (XRD) and transmission electron microscope (TEM) indicated a difference in the dispersing capability of the organoclay.

  3. Sensing Properties of Gas Sensor Based on Adsorption of NO2 with Defect, Pristine, Fe and Si-MoS2 Layer

    Directory of Open Access Journals (Sweden)

    S.R. Shakil

    2014-11-01

    Full Text Available Two-dimensional (2D layered materials are currently being considered as entrant for future electronic devices. Molybdenum disulphide (MoS2 belongs to a family of layered transitional metal dichalcogenides(TMDS,has a unique characteristics of showing intrinsic semiconducting nature is being considered a major advantageous over graphene (which has no intrinsic band gap as a two-dimensional (2D channel material in field effect transistors(FET. In the paper, the results of investigations are presented concerning the affects of adsorption of NO2 gas on the surface of MoS2, defect-MoS2, Si-MoS2 and Fe-MoS2 layer. The changes density of states (DOS and electrostatic difference potential of Si-MoS2 by applying different gate voltage were studied. We proposed that, NO2 might play an important role on MoS2 layer that can be used as gas sensor. In the research, it has been shown that in the case of gas sensor, the adsorption of NO2 with MoS2, Fe-MoS2, Si-MoS2 and defect-MoS2 play an important rule for sensing behavior.

  4. Theoretical analysis of the combined effects of sulfur vacancies and analyte adsorption on the electronic properties of single-layer MoS2

    Science.gov (United States)

    Akdim, Brahim; Pachter, Ruth; Mou, Shin

    2016-05-01

    We report a first-principles theoretical investigation on the electronic structure and electron transport of defective single-layer (SL) MoS2, as well as of corresponding structures adsorbed with benzyl viologen (BV), which was shown to provide improved performance of a field effect transistor. O2 adsorption was included to gain an understanding of the response upon air-exposure. Following analysis of the structure and stability of sulfur single vacancy and line defects in SL MoS2, we investigated the local transport at the adsorbed sites via a transport model that mimics a scanning tunneling spectroscopy experiment. Distinct current-voltage characteristics were indicated for adsorbed oxygen species at a sulfur vacancy. The electronic structures of defective MoS2 indicated the emergence of impurity states in the bandgap due to sulfur defects and oxygen adsorption. Electron transport calculations for the MoS2 surface with an extended defect in a device setting demonstrated that physisorption of BV enhances the output current, while facile chemisorption by O2 upon air-exposure causes degradation of electron transport.

  5. The adsorptive properties of powdered carbon materials with a strongly differentiated porosity and their applications in electroanalysis and solid phase microextraction.

    Science.gov (United States)

    Kuśmierek, K; Sankowska, M; Skrzypczyńska, K; Świątkowski, A

    2015-05-15

    The adsorption of 4-chlorophenol from an aqueous solution on carbonaceous materials (one carbon black and two powdered activated carbons) with a strongly differentiated porosity was investigated. The kinetic data were fitted well to the pseudo-second order model. The amount of 4-chlorophenol adsorbed at equilibrium was increased with an increase in the specific surface area of the tested materials. The adsorption isotherms were analyzed using the Langmuir and Freundlich models. The Langmuir isotherm was slightly favorable (R(2)>0.99) rather than the Freundlich isotherm (R(2)>0.98). Carbon materials were also used for the modification of carbon paste electrodes as well as for the preparation of novel solid phase microextraction fibers. The peak current of the differential pulse voltammetry curves was increased along with the amount of added carbon paste electrode modifier. The signal response was closely related to the porosity of the materials used, and increased with the increase in the specific surface area. The amount of 4-chlorophenol extracted from the samples by the solid phase microextraction fiber's surface was also correlated with the specific surface area of the tested materials. All the novel fibers were better than the commercially available fibers prepared from polidimethylosiloxane. PMID:25660709

  6. Fluoride and lead adsorption on carbon nanotubes

    Institute of Scientific and Technical Information of China (English)

    WANG Shuguang; LI Yanhui

    2004-01-01

    The properties and applications of CNT have been studied extensively since Iijima discovered them in 1991[1,2]. They have exceptional mechanical properties and unique electrical property, highly chemical stability and large specific surface area. Thus far, they have widely potential applications in many fields. They can be used as reinforcing materials in composites[3], field emissions[4], hydrogen storage[5], nanoelectronic components[6], catalyst supports[7], adsorption material and so on. However, the study on the potential application of CNT, environmental protection field in particular, was hardly begun.Long[8] et al. reported that CNT had a significantly higher dioxin removal efficiency than that of activated carbon. The Langmuir adsorption constant is 2.7 × 1052, 1.3 × 1018 respectively. The results indicated that CNT is potential candidate for the removal of micro-organic pollutants. However, the reports on the CNT used as fluoride and heavy metal adsorbent are seldom.In this paper, A novel material, alumina supported on carbon nanotubes (Al2O3/CNT), was prepared from carbon nanotubes and Al(NO3)3. X-ray diffraction (XRD) spectra demonstrate that alumina is amorphous, and scanning electron microscope (SEM) images show that CNT and alumina are homogeneously mixed. Furthermore, the fluoride adsorption behavior on the surface of Al2O3/CNT has been investigated and compared with other adsorbents. The results indicate that Al2O3/CNT has a high adsorption capacity, with a saturation adsorption capacity of 39.4 mg/g. It is also found that the adsorption capacity of Al2O3/CNT is 3.0~4.5 times that of γ-Al2O3while almost equal to that of IRA-410 polymeric resin at 25 ℃. The adsorption isotherms of fluoride on Al2O3/CNT is fit the Freundlich equation well, optimal pH ranging from 5.0 to 9.0.Also in this paper, a novel material, modified carbon nanotubes (CNT), was prepared from carbon nanotubes and HNO3 under boiling condition. Infrared spectroscopy (IR

  7. Adsorption of polar, nonpolar, and substituted aromatics to colloidal graphene oxide nanoparticles

    International Nuclear Information System (INIS)

    We conducted batch adsorption experiments to understand the adsorptive properties of colloidal graphene oxide nanoparticles (GONPs) for a range of environmentally relevant aromatics and substituted aromatics, including model nonpolar compounds (pyrene, phenanthrene, naphthalene, and 1,3-dichlorobenzene) and model polar compounds (1-naphthol, 1-naphthylamine, 2,4-dichlorophenol, and 2,4-dinitrotoluene). GONPs exhibited strong adsorption affinities for all the test compounds, with distribution coefficients on the order of 103–106 L/kg. Adsorption to GONPs is much more linear than to carbon nanotubes (CNTs) and C60, likely because GO nanoflakes are essentially individually dispersed (rendering adsorption sites of similar adsorption energy) whereas CNT/C60 are prone to bundling/aggregation. For a given compound GONPs and CNTs often exhibit different adsorption affinities, which is attributable to the differences in both the morphology and surface chemistry between the two nanomaterials. Particularly, the high surface O-content of GONPs enables strong H-bonding and Lewis acid–base interactions with hydroxyl- and amino-substituted aromatics. -- Highlights: • Graphene oxide nanoparticles (GONPs) exhibit strong adsorption for aromatics. • GONPs show distinctly different adsorption properties than other carbon particles. • Unique surface chemistry and morphology control adsorption properties of GONPs. • Adsorption is relatively linear because GO nanoflakes are individually dispersed. • High surface O-content enables strong H-bonding and Lewis acid–base interactions. -- Colloidal graphene oxide nanoparticles exhibit strong adsorption affinities and characteristic adsorption properties for environmentally relevant aromatics and substituted aromatics

  8. Adsorption of xenon and krypton on shales

    International Nuclear Information System (INIS)

    Parameters for the adsorption of Xe and Kr on shales and related samples have been measured by a method that uses a mass spectrometer as a manometer. The gas partial pressures used were 10-11 atm or less; the corresponding adsorption coverages are only small fractions of a monolayer, and Henry's Law behavior is expected and observed. Heats of adsorption in the range 2 to 7 kcal/mol were observed. Henry constants of the order of magnitude 1 cm3 STP g-1 atm-1 at 0 to 250C are obtained by extrapolation. Adsorption properties are variable by sample, but the general range suggests that shales might be sufficiently good adsorbents that equilibrium adsorption with modern air may account for a nontrivial fraction of the atmospheric inventory of Xe (perhaps even Kr). It seems doubtful, however, that this effect can account for the deficiency of atmospheric Xe in comparison with the planetary gas patterns observed in meteorites. If gas is adsorbed on interior surfaces in shale clays and can communicate with sample exteriors only through very narrow channels, and thus only very slowly, equilibrium adsorption may make substantial contributions to experimentally observed 'trapped' gases without the need for any further trapping mechanism. (author)

  9. The adsorption and separation properties of S-ibuprofen molecularly imprinted membrane%S-布洛芬印迹复合膜的吸附及拆分性能

    Institute of Scientific and Technical Information of China (English)

    赵丹; 程永琪; 张卫东; 任钟旗

    2013-01-01

    A composite membrane ( MIM ) molecularly imprinted with S-ibuprofen has been prepared by using a poly (vinylidene fluoride) (PVDF) membrane as supporting membrane, S-ibuprofen as template, acrylamide (AM) as functional monomer, and ethylene glycol dimethacrylate (EGDMA) as cross-linking agent via free radical polymerization. The adsorption and chiral resolution properties of the MIM for racemic ibuprofen were evaluated. The results indicated that the prepared MIM had a certain specific adsorption ability for S-ibuprofen. The adsorption a-mount increased with increasing ibuprofen concentration from 0. 1 to 0. 5 mmol/L, but the adsorption selectivity factor decreased from 1. 68 to 1. 14. The resolution ability of the MIM was evaluated by permeability testing. The permeation amounts of R-ibuprofen and S-ibuprofen were 0. 378 and 0. 313 μmol/(cm2·h) , respectively, and the separation factor could reach 1. 21.%以聚偏氟乙烯(PVDF)微孔滤膜为基膜,S-布洛芬为模板分子,丙烯酰胺为功能单体,乙二醇二甲基丙烯酸酯为交联剂,采用热引发表面自由基聚合的方式制备了S-布洛芬印迹复合膜,并研究了其对布洛芬外消旋体的吸附及拆分性能.结果表明,该印迹膜对S-布洛芬具有一定的特异性吸附能力,当布洛芬异构体浓度在0.1 ~0.5mmol/L范围内逐渐增大时,吸附量也逐渐增大,吸附选择性因子则由1.68降至1.14;该膜对布洛芬异构体具有一定的拆分能力,渗透实验进行7h,膜对R-布洛芬及S-布洛芬的渗透量分别为0.378和0.313μmol/(cm2 ·h),分离因子可达到1.21.

  10. 氨基功能化SBA-15的制备及对三价铬吸附性能的研究%Preparation of Amino-functionalized SBA-15 and Its Adsorption Property to Cr^3+

    Institute of Scientific and Technical Information of China (English)

    田志茗; 李乐园; 隋朝

    2012-01-01

    Amino-functionalized mesoporous material SBA-15 (NH2-SBA 15) was prepared by a post-grafting method using 3-aminopropyltrimethoxy-silane (APTMS). The NH2-SBA-15 was characterized by X-ray diffraction (XRD), infrared spectroscopy (IR), transmission electron microscopy (TEM), scanning electron microscopy (SEM) and N2 adsorption/desorption isotherms. It was proved that ATPMS was grafted on SBA-15, and NHe-SBA-15 remained to keep the hexagonal, mesoporous structure. Adsorption property of NH2-SBA-15 to Cr^3+ ion was studied. It was found that in an aqueous medium of pH 4. 5 containing 140 mg·L^-1 Cr^3+ ion, the NH2-SBA-15 behaved to adsorb strongly and equilibrium of adsorption was achieved after 6h at the temperature of 60 ℃, and the adsorptive capacity of Cr^3+ ion at equilibrium was 15.59 mg ·L^-1.%以3-氨丙基三乙氧基硅烷(APTMS)为功能化试剂,用后嫁接法对介孔分子筛SBA-15进行化学改性,制备氨基功能化NH2-SBA-15。采用X射线衍射、红外光谱、透射电子显微镜、扫描电子显微镜、N2吸附-脱附等手段对NH2-SBA-15进行了表征。结果表明:ATPES成功地嫁接到介孔材料SBA-15上,NH2-SBA-15仍保持了SBA-15六方介孔结构。将此材料作为Cr抖的有效吸附剂进一步研究NH2-SBA-15的吸附性能,结果表明:介质PH值为4.5、温度为60℃、Cr^3+溶液质量浓度为140mg·L^-1、吸附时间为6h时,吸附剂的吸附量达15.59mg·L^-1。

  11. Ligand and ensemble effects in adsorption on alloy surfaces

    DEFF Research Database (Denmark)

    Liu, Ping; Nørskov, Jens Kehlet

    2001-01-01

    Density functional theory is used to study the adsorption of carbon monoxide, oxygen and nitrogen on various Au/Pd(111) bimetallic alloy surfaces. By varying the Au content in the surface we are able to make a clear separation into geometrical (or ensemble) effects and electronic (or ligand......) effects determining the adsorption properties....

  12. adsorption, eosin, humic, peat

    OpenAIRE

    Anshar, Andi Muhammad

    2015-01-01

    Eosin is one of the dyes commonly used in the industry and has the potential to cause pollution of the water environment. The Eosin pollution treatment methods used in this study was the adsorption method using humin fraction obtained from the peat land comes from Kalimantan. From the research data showed that the adsorption of eosin in humin result of washing with HCl / HF optimum at pH 4 and a contact time of 60 minutes with the adsorption-order rate was 8,4 x 10-3 min-1

  13. Adsorption of Na, Mg, and Al atoms on BN nanotubes

    International Nuclear Information System (INIS)

    Adsorption of three metals (Na, Mg, and Al) on the surface of BN nanotubes (BNNT) has been investigated by using density functional theory. Adsorption energies for Na and Al atoms have been calculated to be about − 0.22 to − 0.61 eV, respectively. Upon the metal adsorption, energy gap between highest occupied and lowest unoccupied orbitals of the tube is dramatically decreased, resulting in enhanced electrical conductivity. However, in the case of Mg atom, the low adsorption energy cannot change electronic property of the tube. The semi-conductive BNNT transform to n-type semiconductor after adsorption of Na atom. The metal adsorption modifies work function of the BNNT and consequently the field-emission current densities of metal-BNNT may be significantly enhanced. - Highlights: ► Adsorption of Na, Mg, and Al atoms on the BN nanotubes (BNNT) was studied. ► Adsorption energies for Na and Al atoms are about − 0.22 to − 0.61 eV, respectively. ► Energy gap of the tube dramatically decreases upon the metals adsorption. ► Semiconductor BNNT transform to n-type ones upon adsorption of Na and Al atoms. ► The field-emission current densities of metal-BNNT may be significantly enhanced.

  14. Adsorption of Na, Mg, and Al atoms on BN nanotubes

    Energy Technology Data Exchange (ETDEWEB)

    Beheshtian, Javad [Department of Chemistry, Shahid Rajaee Teacher Training University, P.O. Box: 16875-163, Tehran (Iran, Islamic Republic of); Peyghan, Ali Ahmadi, E-mail: ahmadi.iau@gmail.com [Young Researchers Club, Islamic Azad University, Islamshahr Branch, Tehran (Iran, Islamic Republic of); Bagheri, Zargham [Physics group, Science department, Islamic Azad University, Islamshahr Branch, P.O. Box: 33135-369, Islamshahr, Tehran (Iran, Islamic Republic of)

    2012-12-30

    Adsorption of three metals (Na, Mg, and Al) on the surface of BN nanotubes (BNNT) has been investigated by using density functional theory. Adsorption energies for Na and Al atoms have been calculated to be about - 0.22 to - 0.61 eV, respectively. Upon the metal adsorption, energy gap between highest occupied and lowest unoccupied orbitals of the tube is dramatically decreased, resulting in enhanced electrical conductivity. However, in the case of Mg atom, the low adsorption energy cannot change electronic property of the tube. The semi-conductive BNNT transform to n-type semiconductor after adsorption of Na atom. The metal adsorption modifies work function of the BNNT and consequently the field-emission current densities of metal-BNNT may be significantly enhanced. - Highlights: Black-Right-Pointing-Pointer Adsorption of Na, Mg, and Al atoms on the BN nanotubes (BNNT) was studied. Black-Right-Pointing-Pointer Adsorption energies for Na and Al atoms are about - 0.22 to - 0.61 eV, respectively. Black-Right-Pointing-Pointer Energy gap of the tube dramatically decreases upon the metals adsorption. Black-Right-Pointing-Pointer Semiconductor BNNT transform to n-type ones upon adsorption of Na and Al atoms. Black-Right-Pointing-Pointer The field-emission current densities of metal-BNNT may be significantly enhanced.

  15. Adsorption of uranium with multiwall carbon nanotubes modified by formaldehyde

    International Nuclear Information System (INIS)

    Purified multiwall carbon nanotubes (MWCNTs) were modified with formaldehyde and the dispersibility of MWCNTs was greatly improved after modification. The modified MWCNTs were used to study the adsorption of uranium from aqueous solution. pH, contact time, temperature, initial concentration of uranium and modified MWCNTs concentrations were investigated to estimate the adsorptive properties. The results show that uranium adsorption percentage strongly depends on the pH, initial concentration of uranium and modified MWCNTs content, and is slightly influenced by contact time, temperature and ionic strength. The adsorptivity increases over the range of pH=2.0-7.0. The maximum adsorptivity is 46.44 mg/g as the initial concentration of uranium reaches 50 μg/mL. The equilibrium data obey both Langmuir and Freundlich isotherms well, and the maximal theoretical adsorption capacity is 55.87 mg/g for the modified MWCNTs. (authors)

  16. Hybrid adsorptive membrane reactor

    Science.gov (United States)

    Tsotsis, Theodore T. (Inventor); Sahimi, Muhammad (Inventor); Fayyaz-Najafi, Babak (Inventor); Harale, Aadesh (Inventor); Park, Byoung-Gi (Inventor); Liu, Paul K. T. (Inventor)

    2011-01-01

    A hybrid adsorbent-membrane reactor in which the chemical reaction, membrane separation, and product adsorption are coupled. Also disclosed are a dual-reactor apparatus and a process using the reactor or the apparatus.

  17. Hybrid adsorptive membrane reactor

    Science.gov (United States)

    Tsotsis, Theodore T.; Sahimi, Muhammad; Fayyaz-Najafi, Babak; Harale, Aadesh; Park, Byoung-Gi; Liu, Paul K. T.

    2011-03-01

    A hybrid adsorbent-membrane reactor in which the chemical reaction, membrane separation, and product adsorption are coupled. Also disclosed are a dual-reactor apparatus and a process using the reactor or the apparatus.

  18. 球形纤维素-钛白粉复合基质的扩张床流体混合特性%Physical and Hydrodynamic Properties of Spherical Cellulose-Titanium Dioxide Composite Matrix for Expanded Bed Adsorption

    Institute of Scientific and Technical Information of China (English)

    雷引林; 林东强; 姚善泾; 刘坐镇; 朱自强

    2003-01-01

    Expanded bed adsorption (EBA) has been widely used in industrial downstream bioprocessing. Solid matrix is the principal pillar supporting the successful application of EBA. A novel spherical cellulose-titanium dioxide composite matrix was prepared through the method of water-in-oil suspension thermal regeneration. Its typical physical properties were wet density 1.18g.cm-3, diameters in the range of 100-300μm, porosity 85.5%,and water content 72.3%. Expansion characteristics and liquid mixing performance of the matrix in expanded bed were investigated using water and 10% (by mass) glycerol solution as mobile phases. The results indicate that the custom-assembled matrix has a stable flow hydrodynamics and exhibits the same degree of liquid-phase mixing or column efficiency as the commercially available Streamline adsorbent.

  19. Adsorption behaviour of bulgur.

    Science.gov (United States)

    Erbaş, Mustafa; Aykın, Elif; Arslan, Sultan; Durak, Atike N

    2016-03-15

    The aim of this research was to determine the adsorption behaviour of bulgur. Three different particle sizes (2dry matter and 4.96-16.57, respectively. Constant k was between 0.85 and 0.93, and GAB equation was determined to fit very well for bulgur adsorption, because of %E values lower than 10%. Bulgur must be stored below 70% relative humidity and with less than 10 g water per 100 g of dry mater. PMID:26575716

  20. Structure sensitivity in adsorption

    DEFF Research Database (Denmark)

    Hammer, Bjørk; Nielsen, Ole Holm; Nørskov, Jens Kehlet

    The structure sensitivity of CO adsorption on different flat, stepped, kinked and reconstructed Pt surfaces is studied using large-scale density-functional calculations. We find an extremely strong structure sensitivity in the adsorption energy with variations up to 1 eV (or 100%) from one...... structure to the next. We propose a model to explain this behavior, and use it to discuss more generally the origin of structure sensitivity in heterogeneous catalysis....

  1. Adsorption Phenomena at Organic-Inorganic Interfaces

    OpenAIRE

    Bachmann, M.; Janke, W.

    2007-01-01

    The qualitative solvent- and temperature-dependent conformational behavior of a peptide in the proximity of solid substrates with different adsorption properties is investigated by means of a simple lattice model. The resulting pseudophase diagrams exhibit a complex structure, which can be understood by analysing the minima of the free-energy landscape in dependence of appropriate system parameters.

  2. Relationship between carbon microstructure, adsorption energy and hydrogen adsorption capacity at different temperatures

    International Nuclear Information System (INIS)

    Various microporous materials such as activated carbons, nano-tubes, synthetic microporous carbons as well as metal organic framework materials are being considered for hydrogen storage applications by means of physical adsorption. To develop materials of practical significance for hydrogen storage it is important to understand the relationships between pore sizes, adsorption energies and adsorption capacities. The pore size distribution (PSD) characterization is traditionally obtained from the analysis of nitrogen adsorption isotherms measured at 77 K. However, a portion of the pores accessible to H2 may not be accessible to N2 at this temperature. Therefore, it was recently proposed to use the DFT analysis of H2 adsorption isotherms to characterize pore structure of materials considered for hydrogen storage applications. In present work, adsorption isotherms of H2 and N2 at cryogenic temperatures are used for the characterization of carbon materials. Adsorption measurements were performed with Autosorb 1 MP (Quantachrome Instruments, Boynton Beach, Florida, USA). As an example, Fig 1 compares PSDs calculated for the activated carbon sample (F400, Calgon Carbon) using combined H2 and N2 data, and using N2 isotherm only. The nitrogen derived PSD does not include certain amount of micropores which are accessible to H2 but not to N2 molecules. Obviously, the difference in the calculated PSDs by the two methods will depend on the actual content of small micropores in a given sample. Carbon adsorption properties can also be characterized by the isosteric heat of adsorption, Qst, related to the adsorption energy and dependent on the carbon pore/surface structure. Fig 2 shows Qst data calculated using the Clausius-Clapeyron equation from H2 isotherms measured at 77 K and 87 K for the carbon molecular sieve CMS 5A (Takeda), oxidized single wall nano-tubes (SWNT), and graphitized carbon black (Supelco). The Qst values decrease with increasing pore sizes. The highest Qst is

  3. Efficient adsorption of phenanthrene by simply synthesized hydrophobic MCM-41 molecular sieves

    Science.gov (United States)

    Hu, Yun; He, Yinyun; Wang, Xiaowen; Wei, Chaohai

    2014-08-01

    Hydrophobic molecular sieve MCM-41 including surfactant template was synthesized by a simple method. The adsorption properties of this material toward phenanthrene were studied. The effects of adsorbent dose and pH value on the adsorption process as well as the adsorption mechanism and reuse performance were investigated. The template-containing MCM-41 showed a significant adsorption for phenanthrene, due to its hydrophobicity created by the surfactant template in MCM-41. The solution pH had little effect on the adsorption capacity. The adsorption kinetic could be fitted well with pseudo-second-order kinetic model. The adsorption equilibrium was fitted well by the linear model, and the adsorption process followed the liquid/solid phase distribution mechanism. The thermodynamic results indicated that the adsorption was a spontaneous and exothermic process.

  4. Adsorption of Lead Ions by Linde type F(K Zeolite

    Directory of Open Access Journals (Sweden)

    Han Chenghui

    2016-01-01

    Full Text Available The Test was to examine the adsorption property of Pb(II irons by Linde type F (K zeolite. The zeolite was synthesized by fly ash. The adsorbent dosage, pH, reaction temperature and reaction time were investigated. The adsorption isotherm and adsorption kinetics equation were studied. The results showed the adsorbent dosage, pH, reaction temperature and reaction time had significant effects on the adsorption of Pb(II irons. The removal rate was improved with the increasing of zeolite dosage. The saturated adsorption capacity was decreased gradually. The adsorption of Pb(II irons tended to saturate when initial pH was 6. With the increasing of temperature, the equilibration time of adsorption was shorter. Langmuir isotherm was more applicable to explain the monolayer adsorption procedure of Pb(II on Linde type F(K zeolite. For adsorption kinetics, pseudo-second order model showed better calculation results.

  5. ADSORPTION OF ATRAZINE ON SELECTED VERTISOLS AND ALFISOLS

    Directory of Open Access Journals (Sweden)

    K.V. Naga Madhuri

    2012-08-01

    Full Text Available Adsorption of atrazine was studied on two Vertisols and two Alfisols varying in their physico-chemical properties. Soils were equilibrated with various concentrations of atrazine using batch techniques.Adsorption affinity for atrazine was approximated by Freundlich constant (Kf, which is a measure of the strength ordegree of adsorption. Kdvalues were calculated for atrazine despite some non-linearity in adsorption on bothVertisols and Alfisols. The Kdvalues are greater for Vertisols than Alfisols and increased with organic carboncontent. Correlations were worked out between extent of adsorption and soil properties and were positivelycorrelated with organic carbon (r = 0.688, clay content ( r = 0.712 and clay + organic carbon (r = 0.708. KOCvalues were calculated taking into account the organic carbon content for both Vertisols and Alfisols

  6. Competitive Protein Adsorption - Multilayer Adsorption and Surface Induced Protein Aggregation

    DEFF Research Database (Denmark)

    Holmberg, Maria; Hou, Xiaolin

    2009-01-01

    high concentration with investigation of single protein adsorption and interdependent adsorption between two specific proteins enables us to map protein adsorption sequences during competitive protein adsorption. Our study shows that proteins can adsorb in a multilayer fashion onto the polymer surfaces......In this study, competitive adsorption of albumin and IgG (immunoglobulin G) from human serum solutions and protein mixtures onto polymer surfaces is studied by means of radioactive labeling. By using two different radiolabels (125I and 131I), albumin and IgG adsorption to polymer surfaces is...... and that the outcome of IgG adsorption is much more sensitive to surface characteristics than the outcome of albumin adsorption. Using high concentrations of protein solution and hydrophobic polymer surfaces during adsorption can induce IgG aggregation, which is observed as extremely high Ig...

  7. Graphene-based porous materials with tunable surface area and CO2 adsorption properties synthesized by fluorine displacement reaction with various diamines.

    Science.gov (United States)

    Li, Baoyin; Fan, Kun; Ma, Xin; Liu, Yang; Chen, Teng; Cheng, Zheng; Wang, Xu; Jiang, Jiaxing; Liu, Xiangyang

    2016-09-15

    A mild, operationally simple and controllable protocol for preparing graphene-based porous materials is essential to achieve a good pore-design development. In this paper, graphene-based porous materials with tunable surface area were constructed by the intercalation of fluorinated graphene (FG) based on the reaction of reactive CF bonds attached to graphene sheets with various amine-terminated molecules. In the porous materials, graphene sheets are like building blocks, and the diamines covalently grafted onto graphene framework act as pillars. Various diamines are successfully grafted onto graphene sheets, but the grafting ratio of diamines and reduction degree of FG differ greatly and depend on the chemical reactivity of diamines. Pillared diamine molecules chemically anchor at one end and are capable of undergoing a different reaction on the other end, resulting in three different conformations of graphene derivatives. Nitrogen sorption isotherms revealed that the surface area and pore distribution of the obtained porous materials depend heavily on the size and structure of diamine pillars. CO2 uptake capacity characterization showed that ethylenediamine intercalated FG achieved a high CO2 uptake density of 18.0 CO2 molecules per nm(2) at 0°C and 1.1bars, and high adsorption heat, up to 46.1kJmol(-1) at zero coverage. PMID:27280538

  8. Photocurrent-voltage of a dye-sensitized nanocrystalline TiO2 solar cells influenced by N719 dye adsorption properties.

    Science.gov (United States)

    Lee, Jae-Wook; Hwang, Kyung-Jun; Park, Dong-Won; Park, Kyung-Hee; Shim, Wang-Geun; Kim, Sang-Chai

    2007-11-01

    Titanium particles of single-phase anatase nanocrystallites were prepared by the hydrolysis of titanium tetraisopropoxide. A dye-sensitized solar cell (DSSC) was fabricated by adsorbing cis-bis(isothiocyanato)bis(2,2'-bipyridyl-4,4'-dicarboxylato)-ruthenium(II)bis-tetrabutylammonium dye (N719) onto TiO2 film. The samples were characterized by XRD, TEM, FE-SEM, AFM, and Brunauer-Emmett-Teller (BET) analysis. The influence of the acetic acid treatment of TiO2 electrode with different concentrations on the photovoltaic performance of DSSC was investigated. It was found that DSSC had better photoelectric performance when the TiO2 electrode was treated by acetic acid of 0.5 M. An equivalent circuit analysis using the one-diode model was used to evaluate the influences of adsorption quantity and acetic acid treatment on the energy conversion efficiency of DSSC. A nonlinear least-square optimization method was used to determine five model parameters. PMID:18047044

  9. Physical properties of nanostructured (PbSx(CuS1−x composite thin films grown by successive ionic layer adsorption and reaction method

    Directory of Open Access Journals (Sweden)

    A.U. Ubale

    2016-03-01

    Full Text Available Nanostructured ternary semiconducting (PbSx(CuS1−x thin films were grown on glass substrates by successive ionic layer adsorption and reaction (SILAR technique at room temperature. The structural, morphological and optical characterizations of the films were carried out by X-ray diffraction, scanning electron microscopy and UV–Vis spectrophotometer respectively. The structural studies revealed that, (PbSx(CuS1−x films are nanocrystalline in nature and have mixed phase of cubic PbS and hexagonal CuS. The optical absorption measurements showed that band gap energy of (PbSx(CuS1−x can be engineered between 2.57 and 2.28 eV by varying compositional parameter ‘x’. The room temperature dc dark electrical resistivity of PbS film is found to be 28.85 Ωcm and it decreases when content of Cu in composite increases and becomes 0.05 Ωcm for pure CuS. The thermo-emf measurements showed that the as deposited (PbSx(CuS1−x films are of n-type. The water angle contact measurements of (PbSx(CuS1−x, revealed that, films are hydrophilic in nature and it could be advantageous in electrochemical application.

  10. 蛋壳及蛋壳膜吸附性质的研究进展%Research progress in adsorption properties of eggshell and eggshell membrane

    Institute of Scientific and Technical Information of China (English)

    韩玉; 汪兰; 孙智达; 杜欣; 杜金平

    2012-01-01

    Since the domestic egg industry is developing rapidly,a lot of egg shell resources are available, which attracted many scientists' eyes. A large number of researches have been done by different researchers. This paper reviewed the usage situation of eggshell and eggshell membrane adsorption ability, which provides new ideas that are helpful for further research and benefit for the development and use of egg shell resources.%目前国内禽蛋行业发展迅速,随之带来了大量的蛋壳资源,这引起很多科学家对蛋壳开发利用的关注,并做了大量的研究。本文主要针对目前国内外对蛋壳及蛋壳膜的吸附性质的研究利用现状做一个概述,以便为蛋壳资源的开发利用以及更深一步的研究提供新的思路。

  11. High surface adsorption properties of carbon-based nanomaterials are responsible for mortality, swimming inhibition, and biochemical responses in Artemia salina larvae

    Energy Technology Data Exchange (ETDEWEB)

    Mesarič, Tina, E-mail: tina.mesaric84@gmail.com [Department of Biology, Biotechnical Faculty, University of Ljubljana (Slovenia); Gambardella, Chiara, E-mail: chiara.gambardella@ge.ismar.cnr.it [Institute of Marine Sciences, National Research Council, Genova (Italy); Milivojević, Tamara, E-mail: milivojevictamara@gmail.com [Department of Biology, Biotechnical Faculty, University of Ljubljana (Slovenia); Faimali, Marco, E-mail: marco.faimali@ismar.cnr.it [Institute of Marine Sciences, National Research Council, Genova (Italy); Drobne, Damjana, E-mail: damjana.drobne@bf.uni-lj.si [Department of Biology, Biotechnical Faculty, University of Ljubljana (Slovenia); Centre of Excellence in Nanoscience and Nanotechnology (CO Nanocentre), Ljubljana (Slovenia); Centre of Excellence in Advanced Materials and Technologies for the Future (CO NAMASTE), Ljubljana (Slovenia); Falugi, Carla, E-mail: carlafalugi@hotmail.it [Department of Earth, Environment and Life Sciences, University of Genova, Genova (Italy); Makovec, Darko, E-mail: darko.makovec@ijs.si [Jožef Stefan Institute, Jamova 39, 1000 Ljubljana (Slovenia); Jemec, Anita, E-mail: anita.jemec@bf.uni-lj.si [Department of Biology, Biotechnical Faculty, University of Ljubljana (Slovenia); Sepčić, Kristina, E-mail: kristina.sepcic@bf.uni-lj.si [Department of Biology, Biotechnical Faculty, University of Ljubljana (Slovenia)

    2015-06-15

    Highlights: • Carbon-based nanomaterials adsorb onto the body surface of A. salina larvae. • Surface adsorption results in concentration–dependent inhibition of larval swimming. • Carbon-based nanomaterials induce no significant mortality of A. salina larvae. - Abstract: We investigated the effects of three different carbon-based nanomaterials on brine shrimp (Artemia salina) larvae. The larvae were exposed to different concentrations of carbon black, graphene oxide, and multiwall carbon nanotubes for 48 h, and observed using phase contrast and scanning electron microscopy. Acute (mortality) and behavioural (swimming speed alteration) responses and cholinesterase, glutathione-S-transferase and catalase enzyme activities were evaluated. These nanomaterials were ingested and concentrated in the gut, and attached onto the body surface of the A. salina larvae. This attachment was responsible for concentration–dependent inhibition of larval swimming, and partly for alterations in the enzyme activities, that differed according to the type of tested nanomaterials. No lethal effects were observed up to 0.5 mg/mL carbon black and 0.1 mg/mL multiwall carbon nanotubes, while graphene oxide showed a threshold whereby it had no effects at 0.6 mg/mL, and more than 90% mortality at 0.7 mg/mL. Risk quotients calculated on the basis of predicted environmental concentrations indicate that carbon black and multiwall carbon nanotubes currently do not pose a serious risk to the marine environment, however if uncontrolled release of nanomaterials continues, this scenario can rapidly change.

  12. High surface adsorption properties of carbon-based nanomaterials are responsible for mortality, swimming inhibition, and biochemical responses in Artemia salina larvae

    International Nuclear Information System (INIS)

    Highlights: • Carbon-based nanomaterials adsorb onto the body surface of A. salina larvae. • Surface adsorption results in concentration–dependent inhibition of larval swimming. • Carbon-based nanomaterials induce no significant mortality of A. salina larvae. - Abstract: We investigated the effects of three different carbon-based nanomaterials on brine shrimp (Artemia salina) larvae. The larvae were exposed to different concentrations of carbon black, graphene oxide, and multiwall carbon nanotubes for 48 h, and observed using phase contrast and scanning electron microscopy. Acute (mortality) and behavioural (swimming speed alteration) responses and cholinesterase, glutathione-S-transferase and catalase enzyme activities were evaluated. These nanomaterials were ingested and concentrated in the gut, and attached onto the body surface of the A. salina larvae. This attachment was responsible for concentration–dependent inhibition of larval swimming, and partly for alterations in the enzyme activities, that differed according to the type of tested nanomaterials. No lethal effects were observed up to 0.5 mg/mL carbon black and 0.1 mg/mL multiwall carbon nanotubes, while graphene oxide showed a threshold whereby it had no effects at 0.6 mg/mL, and more than 90% mortality at 0.7 mg/mL. Risk quotients calculated on the basis of predicted environmental concentrations indicate that carbon black and multiwall carbon nanotubes currently do not pose a serious risk to the marine environment, however if uncontrolled release of nanomaterials continues, this scenario can rapidly change

  13. 磺化木质素系聚合物的结构及其在氧化铝上的吸附特性%THE STRUCTURE CHARACTERISTICS OF SULFONATED LIGNIN-BASED POLYMER AND ITS ADSORPTION PROPERTIES ON ALUMINA

    Institute of Scientific and Technical Information of China (English)

    郭闻源; 杨东杰; 李荣; 邱学青

    2012-01-01

    以造纸黑液中的碱木质素为主要原料,通过磺化和缩聚反应制备了磺化木质素高分子聚合物SBAL.TEM和1H-NMR测试结果表明SBAL是以木质素的疏水骨架为中心,以磺酸基和羧基组成亲水性侧链的球形结构.GPC测试结果表明其重均分子量达到了 24880 Da,是碱木质素的7.38倍,电位滴定测试结果表明,其磺化度达到2.70 mmol·g -1.通过流变曲线、吸附等温线、zeta电位、XPS测试研究了其对氧化铝在水中的分散机理及其吸附特性.掺SBAL的氧化铝浆体,在pH=3~ 12范围内SBAL对其具有良好的分散降黏作用.溶液pH对SBAL的分子构型和吸附特性有较大的影响,随pH增加,SBAL中磺酸基、羧基和酚羟基逐渐电离,分子的伸展程度逐渐增大.随pH增加,SBAL在氧化铝上的吸附质量减少,吸附层由致密逐渐变得疏松,pH小于等电点时以静电吸附为主,pH大于等电点时以非静电的特性吸附为主.当SBAL的用量小于临界值(0.5 wt%)时,其在氧化铝表面形成单分子层吸附,在颗粒间起到静电排斥作用;当用量大于临界值时,其在颗粒表面形成聚集体吸附而起到空间位阻作用.%A sulfonated lignin-based polymer, SBAL, was prepared by sulfomethylation, etherification and polycondensation reaction using alkali lignin from the alkaline pulping spent liquor of bamboo as main material. TEM and H-NMR results showed that the structure of SBAL was loose spherical, the center of which was the hydrophobic skeletons of lignin, the long side chains with sulfonic and carboxyl groups were distributed on its surface. GPC and potentiometric titration results showed that the Mw of SBAL reached 24880 Da, 7.38 times of the alkali lignin, and the sulfonic group content was 2.70 mmol·g-1. The adsorption properties and the dispersion efficiencies of SBAL were investigated by means of isothermal adsorption, XPS, zeta potential and rheological experiments. At pH 3 ~ 12, the SBAL as

  14. Novel nano bearings constructed by physical adsorption

    Science.gov (United States)

    Zhang, Yongbin

    2015-09-01

    The paper proposes a novel nano bearing formed by the physical adsorption of the confined fluid to the solid wall. The bearing is formed between two parallel smooth solid plane walls sliding against one another, where conventional hydrodynamic lubrication theory predicted no lubricating effect. In this bearing, the stationary solid wall is divided into two subzones which respectively have different interaction strengths with the lubricating fluid. It leads to different physical adsorption and slip properties of the lubricating fluid at the stationary solid wall respectively in these two subzones. It was found that a significant load-carrying capacity of the bearing can be generated for low lubricating film thicknesses, because of the strong physical adsorption and non-continuum effects of the lubricating film.

  15. Hydrophobic nano-carrier for lysozyme adsorption

    Indian Academy of Sciences (India)

    CANAN ALTUNBAS; FULDEN ZEYNEP URAL; MURAT UYGUN; NESIBE AVCIBASI; UGUR AVCIBASI; DENIZ AKTAS UYGUN; SINAN AKGÖL

    2016-04-01

    In this work, poly(HEMA–APH) nanoparticles were synthesized by surfactant-free emulsion polymerization technique.Magnetic behaviour was introduced by simple addition of Fe$_3$O$_4$ into the polymerization medium.Characterization of the nanoparticle was carried out by FTIR, ESR, SEM, AFM and EDX analyses. These synthesized magnetic nanoparticles were used for adsorption of lysozyme. For this purpose, adsorption conditions wereoptimized and maximum lysozyme binding capacity was found to be 278.8 mg g$^{−1}$ polymer in pH 7.0 phosphate buffer at 25$^{\\circ}$C. Desorption and reusability properties of the nanoparticles were investigated and lysozyme adsorption efficiency did not change significantly at the end of the 10 successive reuses.

  16. Adsorption behavior of epirubicin hydrochloride on carboxylated carbon nanotubes.

    Science.gov (United States)

    Chen, Zhe; Pierre, Dramou; He, Hua; Tan, Shuhua; Pham-Huy, Chuong; Hong, Hao; Huang, Jilong

    2011-02-28

    The aim of this study was to understand the interaction between carboxylated carbon nanotubes (c-CNTs) and anticancer agents and evaluate the drug-loading ability of c-CNTs. We prepared carboxylated multi-walled carbon nanotubes (c-MWNTs) with nitric acid treatment, then evaluated the adsorption ability of c-MWNTs as adsorbents for loading of the anticancer drug, epirubicin hydrochloride (EPI), and investigated the adsorption behavior of EPI on c-MWNTs. Unmodified multi-walled carbon nanotubes (MWNTs) and single-walled carbon nanotubes (SWNTs) were included as comparative adsorbents. The results showed that carbon nanotubes were able to form supramolecular complexes with EPI via π-π stacking and possessed favorable loading properties as drug carriers. The Freundilich adsorption model was successfully employed to describe the adsorption process. Because of the high surface area and hydrogen bonding, c-MWNTs' adsorption efficiency was the highest and the most stable and their drug-loading capacity was superior to that of MWNTs. With the increase of pH, the adsorption capacity of EPI on the c-MWNTs increased. Low-temperature facilitated the adsorption. More rapid EPI adsorption rate and higher drug-loading ability were observed from c-MWNTs with smaller diameter. Moreover, the adsorption kinetics of EPI on c-MWNTs could be well depicted by using the pseudo-second-order kinetic model. PMID:21145959

  17. Adsorption and Desorption Properties of Phytic Acid from Rice Bran on Anion Exchange Resin%阴离子交换树脂对米糠植酸的吸附解吸性能

    Institute of Scientific and Technical Information of China (English)

    王琳; 罗建平; 查学强; 张海林; 潘利华

    2011-01-01

    通过静态和动态试验研究了6种阴离子交换树脂对植酸的吸附与解吸性能.结果表明,D201树脂对植酸的吸附交换作用较好,且在pH值为2.2时吸附能力最强,静态吸附量达到94.54 mg/g,1.5 mol/L的NaOH溶液利于植酸解吸;Freundlich吸附等温方程可以较好地描述D201树脂对植酸的等温吸附,表明吸附在常温下进行即可;D201树脂对植酸的吸附过程符合Lagergren一级速率方程,表观吸附速率常数k与植酸起始植酸浓度呈负相关关系,与温度呈正相关关系.在D201树脂对植酸的动态吸附与解吸过程中,层析柱管径、上样液浓度、上样液流速和洗脱剂流速对吸附与解吸效果影响较大.%The absorption and desorption properties of phytic acid on anion exchange resin were investigated through static and dynamic experiments. The results showed that D201 resin had the best exchange adsorption performance among all tested resins. The static absorption capacity of D201 resin reached 94. 54 mg/g when the pH value of phytic acid solution was adjusted to 2. 2, and sodium hydroxide solution of 1. 5 mol/L was beneficial to desorption. The absorption behavior of D201 resin for phytic acid obeyed the Freundlich adsorption isotherm equation, indicating that the absorption can be performed under normal temperature. The absorption kinetic data complied with Lagergren pseudo-first-order rate equation. The apparent adsorption rate k has a negative correlation with the initial concentration of phytic acid and has a positive correlation with temperature. As far as the dynamic absorption and desorption of phytic acid on D201 resin was concerned, the effects of chromatography column diameter, sample concentration, sample flowing velocity and eluant flowing velocity were notably observed.

  18. Experimental study and computerized simulation of the elements fixation in trace on mineral oxides. Contribution to the study of natural solids adsorption properties; Etude experimentale et modelisation de la fixation d`elements en trace sur des oxydes mineraux. Contribution a l`etude des proprietes adsorbantes des solides naturels

    Energy Technology Data Exchange (ETDEWEB)

    Marmier, N.

    1994-12-01

    The aim of this work is to identify some natural or synthetical materials allowing the nuclear wastes confinement in underground geological sites by adsorption of radioelements. The materials composition variety which can be used is very large it is then necessary to make use of models able to predict solid complexes behaviour towards the adsorption from known properties of parent constituents. This type of model still does not exist and its focusing requires the demonstration of mineral complexes parent constituents intrinsic properties additivity. The oxides as aluminium or silicon oxides being parent constituents, the author has demonstrated their properties additivity in an aluminium-silicon oxides physical mixture and in an aluminium silicate : the kaolinite. These surface properties have been determined for different quantities of aluminium and silicon oxides in a 0,1 M sodium nitrate. This study has been realized following the steps below : choice of a theoretical concept describing the adsorption adapted to the studied solid-solution system : the surface complexation model at constant capacitance; the focusing of a surface chemical and physical parameters determination method; the verification of these properties additivity on the aluminium-silicon oxides mixture and on the kaolinite. The studied cation for the adsorption on these materials is the ytterbium trivalent ion because the behaviour of the trivalent ions towards the adsorption is not very well known and because the lanthanides are considered as compounds similar to some fission products present in radioactive wastes. The method used for this work is applicable to all the other ions. (O.L.). 73 refs., 91 figs., 14 tabs.

  19. Investigation of the polyvinyl alcohol stabilization mechanism and adsorption properties on the surface of ternary mixed nanooxide AST 50 (Al2O3–SiO2–TiO2)

    International Nuclear Information System (INIS)

    A new adsorbent consisting of fumed, mixed alumina, silica, and titania in various proportions (AST 50) was investigated. The studied material was prepared by chemical vapor deposition method. The diameter of AST 50 primary particles was equal to about 51 nm which denotes that it can be classified as a nanomaterial. In the presented paper, the adsorption properties of polyvinyl alcohol on the ternary oxide were investigated. The polymer macromolecules were characterized by two different molecular weights and degree of hydrolysis. The polymer adsorption reaches the maximum at pH 3 and decreases with the solution pH rise. The reduction of the adsorbed PVA macromolecules is related to the electrostatic repulsion forces occurring in the studied system. The AST 50 point of zero charge (pHpzc) obtained from the potentiometric titration is equal to 4.7. Due to the nonionic character of the analyzed macromolecular compound, the polymer attendance has an insignificant effect on the AST 50 surface charge density. In the case of the adsorbent particles zeta potential, the obtained dependencies are different in the absence and presence of PVA. The shift of the slipping plane and displacement of the counter-ions from Stern layer by the adsorbed polymer chains have the greatest effect on the ζ potential value. The stability measurements indicate that the AST 50 suspensions in the presence of the background electrolyte at pH 3 and 6 are unstable. In turn, in an alkaline medium the mixed oxide suspensions exhibit the highest durability, which is a result of a large number of the negative charges on the AST 50 surface. The addition of PVA 100 significantly improves the suspension stability at pH 3 and 6; at higher pH value, the polymer presence does not influence the system durability. It is related to the steric and electrosteric stabilization of the colloidal particles by the adsorbed polyvinyl alcohol macromolecules

  20. Synthesis of decoupage-like carbon sheets and their adsorption properties%剪纸状碳的合成及其吸附性能

    Institute of Scientific and Technical Information of China (English)

    郑贤东; 朱永春; 鞠治成; 李倩文; 钱逸泰

    2011-01-01

    以二茂铁和四氯乙烯作为反应物,采用热解法在600℃反应10 h得到一种高产率的剪纸状的碳片.扫描电镜的结果表明,剪纸状碳材料的厚度为20~40 nm,宽度为100~200nm.通过氮气吸附-脱附等温曲线计算出产物的比表面积高达1 209m2/g,孔径分布在0.58~1.2 nm之间.一系列对比实验表明,合成剪纸状碳材料的最佳条件为:0.093 g二茂铁,反应温度为600℃,反应时间为10 h.通过调整二茂铁与四氯乙烯的比例,可控制产物的形貌从剪纸状转化为空心球.剪纸状碳对于苯酚的吸附性能(82%)要远高于对罗丹明B的吸附性能(48%),并对其给出了可能的解释.%Decoupage-like carbon sheets(DLCSs)were obtained on a large scale by pyrolysis of tetrachloroethylene and ferrocene in an autoclave at 600 ℃ for 10 h.The scanning electron microscopy(SEM)images show that the thickness and the width of DLCSs are about 20~40 nm,100~200 nm,respectively.The nitrogen adsorption/desorption isotherm experiments reveal that the Brunauer-Emmett-Teller(BET)specific surface area of the product is 1 209 m2/g and the pore-size distribution is concentrated in the range of 0.58 ~ 1.2 nm.A series of comparative experimental results demonstrate that the most favorable temperature,amount of ferrocene and reaction time are 600 ℃,0.093 g and 10 h for synthesis of DLCSs.By adjusting reaction parameters,hollow carbon spheres and carbon sheets can also be selectively prepared using onepot reactions.A possible formation mechanism for the DLCSs was proposed based on the diffusion-limited aggregation(DLA)model.The adsorption behavior of DLCSs were evaluated by the removal of phenol and Rhodamine B(RB),which can remove about 82% of phenol and 48%of RB without any other additives.A possible reason for this phenomenon was also discussed.

  1. Regenerative adsorption distillation system

    KAUST Repository

    Ng, Kim Choon

    2013-12-26

    There is provided a regenerative adsorption distillation system comprising a train of distillation effects in fluid communication with each other. The train of distillation effects comprises at least one intermediate effect between the first and last distillation effects of the train, each effect comprising a vessel and a condensing tube for flow of a fluid therein. The system further comprises a pair of adsorption-desorption beds in vapour communication with the last effect and at least one intermediate effect, wherein the beds contain an adsorbent that adsorbs vapour from the last effect and transmits desorbed vapour into at least one of the intermediate effect.

  2. Hydrogen adsorption on sulphur-doped SiC nanotubes

    Science.gov (United States)

    Sevak Singh, Ram

    2016-07-01

    Hydrogen (H2) is an energy carrier and clean fuel that can be used for a broad range of applications that include fuel cell vehicles. Therefore, development of materials for hydrogen storage is demanded. Nanotubes, in this context, are appropriate materials. Recently, silicon carbide nanotube (SiCNTs) have been predicted as potential nanomaterials for hydrogen storage, and atomic doping into the nanotubes improves the H2 adsorption. Here, we report H2 adsorption properties of sulphur-doped (S-doped) SiCNTs using first-principles calculations based on density functional theory. The H2 adsorption properties are investigated by calculations of energy band structures, density of states (DOS), adsorption energy and Mulliken charge population analysis. Our findings show that, compared to the intrinsic SiCNT, S-doped SiCNT is more sensitive to H2 adsorption. H2 gas adsorption on S-doped C-sites of SiCNT brings about significant modulation of the electronic structure of the nanotube, which results in charge transfer from the nanotube to the gas, and dipole–dipole interactions cause chemisorptions of hydrogen. However, in the case of H2 gas adsorption on S-doped Si-sites of the nanotube, lesser charge transfer from the nanotube to the gas results in physisorptions of the gas. The efficient hydrogen sensing properties of S-doped SiCNTs, studied here, may have potential for its practical realization for hydrogen storage application.

  3. Physical adsorption and molecular dynamics

    International Nuclear Information System (INIS)

    Some aspects of noble gases adsorption (except He) on graphite substracts are reviewed. Experimental results from this adsorption are analyzed and compared with molecular dynamics calculations. (L.C.)

  4. 大尺寸SiO2大孔材料的表面改性及其吸附陛能%Surface Modified Large-sized SiO2 Macroporous Materials and their Adsorption Properties

    Institute of Scientific and Technical Information of China (English)

    张群; 梁云霄; 张育淇

    2012-01-01

    以具有三维骨架结构的环氧树脂大孔聚合物为整体型模板,利用硅酸酯原位溶胶-凝胶过程和高温烧结法制备出大尺寸SiO2大孔材料,通过水热法用铝酸钠对材料进行表面改性,得到铝掺杂SiO2大孔材料(Al-SiO2),并用SEM、FTIR和XPS对大孔材料进行了表征.以Cu^2+和Pb^2+为模拟污染物,研究改性大孔材料的吸附性能.结果表明:改性大孔材料对Cu^2+和Pb^2+均具有良好吸附能力;Al-SiO2对Cu^2+和Pb^2+的最大吸附量分别为71mg·g^-1和138mg·g^-1,0.100gAl-SiO2对100mL50mg·L^-1水溶液中Pb^2+的去除率达到95.3%,重复使用3次后的去除率保持在89.8%.%Large-sized SiO2 macroporous materials are prepared using a three-dimensional (3D) skeletal epoxy resin macroporous polymer as template through an in situ sol-gel process of ethyl silicate and a subsequent calcination at high temperature. The SiO2 macroporous materials are modified with sodium aluminate through hydrothermal method. The Al-doped SiO2 macroporous materials (Al-SiO2) are obtained and characterized by SEM, FTIR and XPS. Cu^2+ and Pb^2+ are selected as simulative pollutants, the adsorption properties of the modified SiO2 macroporous materials are investigated. The results show that the modified macroporous materials have satisfactory adsorption capacity for Cu^2+ and Pb^2+. Using Al-SiO2 as adsorbents, the maximum adsorption capacities of Cu^2+ and Pb^2+ are 71 mg.g^-1 and 138 mg.g^-1, respectively. The removal efficiency of Pb^2+ is found to be 95.3% at an initial concentration of 50 mg·L^-1, 100 mL aqueous solution and 0.100 g Al-SiO2. After 3 cycles of adsorption, 89.8% removal efficiency of Pb^2+ is maintained.

  5. Adsorption of caffeic acid on titanium dioxide: A spectroscopic study

    Science.gov (United States)

    Barreto, Wagner José; Ando, Rômulo A.; Estevão, Bianca Martins; Zanoni, Kassio Papi da Silva

    2012-06-01

    Caffeic acid is an ortho-phenol found in vegetable tissues presenting important properties such as carcinogenesis inhibitor, anti-oxidant, anti-viral, anti-inflammatory and anti-rheumatic actions. It was observed that caffeic acid was not degraded in daylight during the adsorption on TiO2 at pH 4.8. The adsorption fit very well to a Brunauer-Emmett-Teller isotherm equation with a monolayer coverage of 68.15 mg gTiO-1 and saturation coverage of 195.4 mg gTiO-1. A strong adsorption of caffeic acid was verified on TiO2 for the dry solid obtained from the mixture. The Raman and IR spectroscopies revealed that the adsorption should occur through the interaction of the diphenol oxygens with contribution of CC double bond of the acrylic group, however, the carboxylic acid group did not have participation in the adsorption.

  6. Porous organic polymers with anchored aldehydes: A new platform for post-synthetic amine functionalization en route for enhanced CO2 adsorption properties

    KAUST Repository

    Guillerm, Vincent

    2014-01-01

    A novel porous organic polymer has been synthesized using the molecular building block approach to deliberately encompass aldehyde functionalities amenable to post functionalization. The resultant porous framework allows a facile, one-step quantitative and post-synthetic functionalization by amines, permitting enhanced CO2 sorption properties. © 2014 The Royal Society of Chemistry.

  7. The adsorption, stability and properties of Mn6Cr Single-Molecule-Magnets studied by means of nc-AFM, STM, XAS and Spin-resolved Photoelectron Spectroscopy

    International Nuclear Information System (INIS)

    The ionic single-molecule-magnet [MnIII6CrIII]3 with corresponding three counterions has been deposited on different surfaces and studied with respect to its structure and its electronic and magnetic properties. This is the first time that spin polarization of photoelectrons ejected by means of circularly polarized synchrotron radiation has been measured in a single-molecule-magnet.

  8. New Adsorption Methods.

    Science.gov (United States)

    Wankat, Phillip C.

    1984-01-01

    Discusses a simple method for following the movement of a solute in an adsorption or ion exchange system. This movement is used to study a variety of operational methods, including continuous flow and pulsed flow counter-current operations and simulated counter-current systems. Effect of changing thermodynamic variables is also considered. (JM)

  9. Adsorption on the carbon nanotubes

    Institute of Scientific and Technical Information of China (English)

    DING Yi; YANG Xiao-bao; NI Jun

    2006-01-01

    Adsorption on single walled carbon nanotubes (SWCNTs) is a subject of growing experimental and theoretical interest.The possible adsorbed patterns of atoms and molecules on the single-walled carbon nanotubes vary with the diameters and chirality of the tubes due to the confinement.The curvature of the carbon nanotube surface enlarges the distance of the adsorbate atoms and thus enhances the stability of high coverage structures of adsorbate.There exist two novel high-coverage stable structures of potassium adsorbed on SWCNTs,which are not stable on graphite.The electronic properties of SWCNTs can be modified by adsorbate atoms and metal-semiconductor and semiconductor-semi-conductor transitions can be achieved by the doping of alkali atoms.

  10. Lead adsorption capacities of different components in natural surface coatings

    Institute of Scientific and Technical Information of China (English)

    DONG De-ming; HUA Xiu-yi; LI Yu; JI Liang; ZHANG Jing-jing

    2004-01-01

    Pb adsorption capacities of Fe oxide, Mn oxide and organic materials in natural surface coatings( biofilms and associated minerals) collected in three lakes, two ponds and a river in Jilin Province, China and Cayuga Lake in US were studied. A novel extraction technique was employed to remove one or more component(s) from the surface coatings. Pb adsorption to surface coatings before and after extraction was performed to determine the adsorptive properties of the extracted component(s). The statistical analysis of observed Pb adsorption was carried out using nonlinear least squares fitting(NLSF) to estimate the Pb adsorption capacity of each component of surface coatings. For each body of water, the estimated Pb adsorption capacity of Mn oxide(mol Pb/mol Mn) was significantly higher than that of Fe oxide( mol Pb/ mol Fe). The value of estimated adsorption capacities of organic materials with the unit mol Pb per kg COD was similar to or less than that of Fe oxides with the unit mol Pb per mol Fe. Comparison of components of surface coatings in different waters showed that the estimated Pb adsorption capacities of components in surface coatings developed in different natural waters were different,especially for Mn oxides.

  11. Textural Characterization and Energetics of Porous Solids by Adsorption Calorimetry

    Directory of Open Access Journals (Sweden)

    Vanessa Silenia Garcia-Cuello

    2011-06-01

    Full Text Available An adsorption microcalorimeter was designed and built in our laboratory and used for the determination of differential adsorption heats in different samples of porous solids: activated carbon granules, activated carbon pellets, an activated carbon monolith and a zeolite sample. This work shows the relationship between adsorption heat and the pore size of different porous solids using adsorption of NH3, CO and N2O. The result shows that the thermal effect can be related with textural properties and superficial chemical groups of the studied porous solids. The values of differential heats of N2O adsorption in the investigated systems have shown that this interaction is weaker than that with CO. Small amounts of N2O are chemisorbed in the investigated systems. For the room temperature adsorption of N2O, the strongest active sites for the interaction with Brönsted acid groups in the ACM structure were identified. The values determined are between −60 kJ/mol and −110 kJ/mol for ZMOR and ACM, respectively, for the adsorption of N2O and −95 kJ/mol and −130 kJ/mol for the adsorption of CO.

  12. Adsorption behavior of some radionuclides on the Chinese weathered coal

    International Nuclear Information System (INIS)

    The equilibrium and kinetic properties of Am(III), Eu(III) and Cs(I) ions adsorption by three weathered coals (WCs) from China, have been investigated in batch stirred-tank experiments. The effects of contact time, solution acidity and initial sorbate concentration on the adsorption of Am(III), Eu(III) and Cs(I) by Yuxian(YX) Tongchuan (TC) and Pingxiang (PX) WC were evaluated. The radionuclide ions are able to form complex compounds with carboxylic and phenolic groups of WCs and they are also bounded with phenolic groups even at high acidity reaction solution (>0.1 mol/L). Mechanisms including ion exchange, complexation and adsorption to the coal surface are possible in the sorption process. The acidity of the solution played an important role in the adsorption. Even acidity as high as 0.1 mol/L, 60% of Am(III) or Eu(III), 40% of Cs(I) were found to be sorbed on the YX WC, which had the best adsorption capacity for Am(III) and Eu(III). Our batch adsorption studies showed the equilibrium adsorption data fit the linear Langmuir and Freundlich adsorption isotherm. The maximum equilibrium uptake of Eu(III) were 0.412, 3.701, 5.446 mmol/g for JXWC, TCWC and YXWC, respectively

  13. Albumin adsorption on oxide thin films studied by spectroscopic ellipsometry

    Energy Technology Data Exchange (ETDEWEB)

    Silva-Bermudez, P., E-mail: suriel21@yahoo.com [Instituto de Investigaciones en Materiales, Universidad Nacional Autonoma de Mexico, Circuito Exterior s/n, C.U., 04510, Mexico D.F. (Mexico); Unidad de Posgrado, Facultad de Odontologia, Universidad Nacional Autonoma de Mexico, CU, 04510, Mexico D.F. (Mexico); Rodil, S.E.; Muhl, S. [Instituto de Investigaciones en Materiales, Universidad Nacional Autonoma de Mexico, Circuito Exterior s/n, C.U., 04510, Mexico D.F. (Mexico)

    2011-12-15

    Thin films of tantalum, niobium, zirconium and titanium oxides were deposited by reactive magnetron sputtering and their wettability and surface energy, optical properties, roughness, chemical composition and microstructure were characterized using contact angle measurements, spectroscopic ellipsometry, profilometry, X-ray photoelectron spectroscopy and X-ray diffraction, respectively. The purpose of the work was to correlate the surface properties of the films to the Bovine Serum Albumin (BSA) adsorption, as a first step into the development of an initial in vitro test of the films biocompatibility, based on standardized protein adsorption essays. The films were immersed into BSA solutions with different protein concentrations and protein adsorption was monitored in situ by dynamic ellipsometry; the adsorption-rate was dependent on the solution concentration and the immersion time. The overall BSA adsorption was studied in situ using spectroscopic ellipsometry and it was found to be influenced by the wettability of the films; larger BSA adsorption occurred on the more hydrophobic surface, the ZrO{sub 2} film. On the Ta{sub 2}O{sub 5}, Nb{sub 2}O{sub 5} and TiO{sub 2} films, hydrophilic surfaces, the overall BSA adsorption increased with the surface roughness or the polar component of the surface energy.

  14. Effect of Li Adsorption on the Electronic and Hydrogen Storage Properties of Acenes: A Dispersion-Corrected TAO-DFT Study

    CERN Document Server

    Seenithurai, Sonai

    2016-01-01

    Due to the presence of strong static correlation effects and noncovalent interactions, accurate prediction of the electronic and hydrogen storage properties of Li-adsorbed acenes with n linearly fused benzene rings (n = 3 - 8) has been very challenging for conventional electronic structure methods. To meet the challenge, we study these properties using our recently developed thermally-assisted-occupation density functional theory (TAO-DFT) with dispersion corrections. In contrast to pure acenes, the binding energies of H2 molecules on Li-adsorbed acenes are in the ideal binding energy range (about 20 to 40 kJ/mol per H2). Besides, the H2 gravimetric storage capacities of Li-adsorbed acenes are in the range of 9.9 to 10.7 wt%, satisfying the United States Department of Energy (USDOE) ultimate target of 7.5 wt%. On the basis of our results, Li-adsorbed acenes can be high-capacity hydrogen storage materials for reversible hydrogen uptake and release at ambient conditions.

  15. Effect of Li Adsorption on the Electronic and Hydrogen Storage Properties of Acenes: A Dispersion-Corrected TAO-DFT Study

    Science.gov (United States)

    Seenithurai, Sonai; Chai, Jeng-Da

    2016-01-01

    Due to the presence of strong static correlation effects and noncovalent interactions, accurate prediction of the electronic and hydrogen storage properties of Li-adsorbed acenes with n linearly fused benzene rings (n = 3–8) has been very challenging for conventional electronic structure methods. To meet the challenge, we study these properties using our recently developed thermally-assisted-occupation density functional theory (TAO-DFT) with dispersion corrections. In contrast to pure acenes, the binding energies of H2 molecules on Li-adsorbed acenes are in the ideal binding energy range (about 20 to 40 kJ/mol per H2). Besides, the H2 gravimetric storage capacities of Li-adsorbed acenes are in the range of 9.9 to 10.7 wt%, satisfying the United States Department of Energy (USDOE) ultimate target of 7.5 wt%. On the basis of our results, Li-adsorbed acenes can be high-capacity hydrogen storage materials for reversible hydrogen uptake and release at ambient conditions. PMID:27609626

  16. Effect of Li Adsorption on the Electronic and Hydrogen Storage Properties of Acenes: A Dispersion-Corrected TAO-DFT Study.

    Science.gov (United States)

    Seenithurai, Sonai; Chai, Jeng-Da

    2016-01-01

    Due to the presence of strong static correlation effects and noncovalent interactions, accurate prediction of the electronic and hydrogen storage properties of Li-adsorbed acenes with n linearly fused benzene rings (n = 3-8) has been very challenging for conventional electronic structure methods. To meet the challenge, we study these properties using our recently developed thermally-assisted-occupation density functional theory (TAO-DFT) with dispersion corrections. In contrast to pure acenes, the binding energies of H2 molecules on Li-adsorbed acenes are in the ideal binding energy range (about 20 to 40 kJ/mol per H2). Besides, the H2 gravimetric storage capacities of Li-adsorbed acenes are in the range of 9.9 to 10.7 wt%, satisfying the United States Department of Energy (USDOE) ultimate target of 7.5 wt%. On the basis of our results, Li-adsorbed acenes can be high-capacity hydrogen storage materials for reversible hydrogen uptake and release at ambient conditions. PMID:27609626

  17. A coordination chemistry approach for modeling trace element adsorption

    International Nuclear Information System (INIS)

    The traditional distribution coefficient, Kd, is highly dependent on the water chemistry and the surface properties of the geological system being studied and is therefore quite inappropriate for use in predictive models. Adsorption, one of the many processes included in Kd values, is described here using a coordination chemistry approach. The concept of adsorption of cationic trace elements by solid hydrous oxides can be applied to natural solids. The adsorption process is thus understood in terms of a classical complexation leading to the formation of surface (heterogeneous) ligands. Applications of this concept to some freshwater, estuarine and marine environments are discussed. (author)

  18. AIR SEPARATION BY PRESSURE SWING ADSORPTION USING SUPERIOR ADSORBENTS

    Energy Technology Data Exchange (ETDEWEB)

    Ralph T. Yang

    2001-08-31

    Li-X zeolite (Si/Al = 1.0) is currently the best sorbent for use in the separation of air by adsorption processes. In particular, pressure swing adsorption (PSA) using zeolite sorbents is being increasingly used for air separation. Silver is also known to strongly affect the adsorptive properties of zeolites; and it is known that thermal vacuum dehydration of silver zeolites leads to the formation of silver clusters within the zeolite. In this work we have synthesized type X zeolites containing Ag and also varying mixtures of Li and Ag. In this project, we developed the Ag-containing zeolite as the best sorbent for air separation. We have also studied Co-ligand compounds as oxygen-selective sorbents. Syntheses, structural characterization and adsorption properties have been performed on all sorbents. The results are described in detail in 5 chapters.

  19. Oxygen adsorption on pyrite (100) surface by density functional theory

    Institute of Scientific and Technical Information of China (English)

    孙伟; 胡岳华; 邱冠周; 覃文庆

    2004-01-01

    Pyrite (FeS2) bulk and (100) surface properties and the oxygen adsorption on the surface were studied by using density functional theory methods. The results show that in the formation of FeS2 (100) surface, there exists a process of electron transfer from Fe dangling bond to S dangling bond. In this situation, surface Fe and S atoms have more ionic properties. Both Fe2+ and S2- have high electrochemistry reduction activity, which is the base for oxygen adsorption. From the viewpoint of adsorption energy, the parallel form oxygen adsorption is in preference.The result also shows that the state of oxygen absorbed on FeS2 surface acts as peroxides rather than O2.

  20. Managing numerical errors in random sequential adsorption

    Science.gov (United States)

    Cieśla, Michał; Nowak, Aleksandra

    2016-09-01

    Aim of this study is to examine the influence of a finite surface size and a finite simulation time on a packing fraction estimated using random sequential adsorption simulations. The goal of particular interest is providing hints on simulation setup to achieve desired level of accuracy. The analysis is based on properties of saturated random packing of disks on continuous and flat surfaces of different sizes.

  1. Traps for phosphorus adsorption

    International Nuclear Information System (INIS)

    Several AL2O3 supported oxides such as: NiO, CuO, Co2O3 BaO, CeO2 and ZnO were investigated for phosphorus adsorption. Zno/y-Al2O3 exhibited the highest phosphorus adsorption capacity. However, since it diminishes the activity of to the reaction mixture it should be located upstream of the NoX catalyst, i.e. 0,3% Pd-H-MOR, in order to protect it against p poisoning. The treatment procedure with citric acid was effective for the removal of more than 70% phosphorus from the adsorbent, ZnO/y-Al2O3

  2. Adsorption dynamics of methyl violet onto granulated mesoporous carbon: Facile synthesis and adsorption kinetics.

    Science.gov (United States)

    Kim, Yohan; Bae, Jiyeol; Park, Hosik; Suh, Jeong-Kwon; You, Young-Woo; Choi, Heechul

    2016-09-15

    A new and facile one-step synthesis method for preparing granulated mesoporous carbon (GMC) with three-dimensional spherical mesoporous symmetry is prepared to remove large molecular weight organic compounds in aqueous phase. GMC is synthesized in a single step using as-synthesized mesoporous carbon particles and organic binders through a simple and economical synthesis approach involving a simultaneous calcination and carbonization process. Characterization results obtained from SEM, XRD, as well as surface and porosity analysis indicate that the synthesized GMC has similar physical properties to those of the powdered mesoporous carbon and maintains the Brunauer-Emmett-Teller (BET) surface area and pore volume because the new synthesis method prevents the collapse of the pores during the granulation process. Batch adsorption experiments revealed GMC showed a substantial adsorption capacity (202.8 mg/g) for the removal of methyl violet as a target large molecular contaminant in aqueous phase. The mechanisms and dynamics modeling of GMC adsorption were also fully examined, which revealed that surface diffusion was rate limiting step on adsorption process of GMC. Adsorption kinetics of GMC enables 3 times faster than that of granular activated carbon in terms of surface diffusion coefficient. This is the first study, to the best of our knowledge, to synthesize GMC as an adsorbent for water purification by using facile granulation method and to investigate the adsorption kinetics and characteristics of GMC. This study introduces a new and simple method for the synthesis of GMC and reveals its adsorption characteristics for large molecular compounds in a water treatment. PMID:27262123

  3. General framework for adsorption processes on dynamic interfaces

    Science.gov (United States)

    Schmuck, Markus; Kalliadasis, Serafim

    2016-03-01

    We propose a novel and general variational framework modelling particle adsorption mechanisms on evolving immiscible fluid interfaces. A by-product of our thermodynamic approach is that we systematically obtain analytic adsorption isotherms for given equilibrium interfacial geometries. We validate computationally our mathematical methodology by demonstrating the fundamental properties of decreasing interfacial free energies by increasing interfacial particle densities and of decreasing surface pressure with increasing surface area.

  4. Molecular simulations in microporous materials: adsorption and separation

    OpenAIRE

    J. M. Castillo

    2010-01-01

    The adsorption of water on hydrophobic zeolites such as silicalite and on hydrophilic MOF (metal-organic framework), Cu-BTC, is completely different, as described in chapters 2 and 4. While in hydrophobic materials water adsorption isotherms are very steep and difficult to measure, both experimentally and by simulation, in hydrophilic materials water adsorbs easily and its isotherms are similar to the isotherms of other molecules. The key property to understand these differences is the dipole...

  5. Adsorption Behaviour of Liquid 4He on Cesium Substrates

    OpenAIRE

    Iov, Valentin

    2004-01-01

    The aim of this thesis is to investigate the wetting properties of 4He on cesium substrates using optical and electrical methods. Due to the fact that the cesium substrates are deposited at low temperatures onto a thin silver underlayer, it is necessary firstly to study and understand the adsorption of helium on silver. The work presented here is structured as follows: some of the fundamental concepts on the theory of physisorbed films, such as van der Waals interaction, adsorption isotherms ...

  6. Hydrogen adsorption on bimetallic PdAu(111) surface alloys:minimum adsorption ensemble, ligand and ensemble effects, and ensemble confinement

    OpenAIRE

    Takehiro, Naoki; Liu, Ping; Bergbreiter, Andreas; K. Nørskov, Jens; Behm, R. Juergen

    2014-01-01

    The adsorption of hydrogen on structurally well defined PdAu-Pd(111) monolayer surface alloys was investigated in a combined experimental and theoretical study, aiming at a quantitative understanding of the adsorption and desorption properties of individual PdAu nanostructures. Combining the structural information obtained by high resolution scanning tunneling microscopy (STM), in particular on the abundance of specific adsorption ensembles at different Pd surface concentrations, with informa...

  7. About using microwave irradiation in competitive adsorption processes

    International Nuclear Information System (INIS)

    The use of microwave radiation for improving adsorption selectivity towards some species in co-adsorption processes is investigated. The microwave effect is evaluated and discussed at a microscopic level based on a set of co-adsorption experiments conducted with various zeolites (NaX, NaY, DAY, NaA) and using two different couples of adsorbates contrasted in polarity: H2O/CO2 and H2O/Toluene. These experiments conducted without heating, under microwave or conventional thermal heating, demonstrate that microwaves do not affect co-adsorption equilibrium by another manner than the thermodynamic effect. Temperature is the controlling parameter of the adsorption equilibrium and adsorption selectivity is identical as soon as the same temperature is reached, independently of the heating system which is used. Nevertheless, temperature heterogeneity, often obtained under microwaves, can be a way of improving selectivity and co-adsorption processes. Simulations of the temperature bed distribution under microwave irradiation have been made for particular zeolite bed configurations. The model accounts for the electromagnetic wave propagation coupled to energy conversion and heat transfer phenomena. From these results, a new process combining several adsorbent beds of contrasted selectivity towards species and of different dielectric properties is proposed. It uses microwave regeneration taking advantage of the temperature heterogeneity. It is a way to obtain energy efficient adsorption processes and high purity adsorbate recovery. -- Highlights: ► Experimental study of co-adsorption under microwaves. ► Microwaves affect only co-adsorption equilibrium by the thermodynamic effect. ► Modelling of the temperature bed distribution under microwave irradiation. ► A new efficient process is proposed for high purity adsorbate recovery

  8. Efficient adsorption of phenanthrene by simply synthesized hydrophobic MCM-41 molecular sieves

    International Nuclear Information System (INIS)

    Graphical abstract: - Highlights: • Simply synthesized template-containing MCM-41 is used for phenanthrene adsorption. • Template-containing MCM-41 has much higher adsorption capacity than pure MCM-41. • The adsorption process follows the liquid/solid phase distribution mechanism. - Abstract: Hydrophobic molecular sieve MCM-41 including surfactant template was synthesized by a simple method. The adsorption properties of this material toward phenanthrene were studied. The effects of adsorbent dose and pH value on the adsorption process as well as the adsorption mechanism and reuse performance were investigated. The template-containing MCM-41 showed a significant adsorption for phenanthrene, due to its hydrophobicity created by the surfactant template in MCM-41. The solution pH had little effect on the adsorption capacity. The adsorption kinetic could be fitted well with pseudo-second-order kinetic model. The adsorption equilibrium was fitted well by the linear model, and the adsorption process followed the liquid/solid phase distribution mechanism. The thermodynamic results indicated that the adsorption was a spontaneous and exothermic process

  9. Efficient adsorption of phenanthrene by simply synthesized hydrophobic MCM-41 molecular sieves

    Energy Technology Data Exchange (ETDEWEB)

    Hu, Yun, E-mail: huyun@scut.edu.cn; He, Yinyun; Wang, Xiaowen; Wei, Chaohai

    2014-08-30

    Graphical abstract: - Highlights: • Simply synthesized template-containing MCM-41 is used for phenanthrene adsorption. • Template-containing MCM-41 has much higher adsorption capacity than pure MCM-41. • The adsorption process follows the liquid/solid phase distribution mechanism. - Abstract: Hydrophobic molecular sieve MCM-41 including surfactant template was synthesized by a simple method. The adsorption properties of this material toward phenanthrene were studied. The effects of adsorbent dose and pH value on the adsorption process as well as the adsorption mechanism and reuse performance were investigated. The template-containing MCM-41 showed a significant adsorption for phenanthrene, due to its hydrophobicity created by the surfactant template in MCM-41. The solution pH had little effect on the adsorption capacity. The adsorption kinetic could be fitted well with pseudo-second-order kinetic model. The adsorption equilibrium was fitted well by the linear model, and the adsorption process followed the liquid/solid phase distribution mechanism. The thermodynamic results indicated that the adsorption was a spontaneous and exothermic process.

  10. The role of the internal molecular free volume in defining organic porous copolymer properties: tunable porosity and highly selective CO2 adsorption.

    Science.gov (United States)

    Zhang, Yindong; Zhu, Yunlong; Guo, Jun; Gu, Shuai; Wang, Yuanyuan; Fu, Yu; Chen, Dongyang; Lin, Yijun; Yu, Guipeng; Pan, Chunyue

    2016-04-20

    A series of novel azo-functionalized copolymerized networks (simply known as NOP-34 series) with tunable permanent microporosity and highly selective carbon dioxide capture are disclosed. The synthesis was accomplished by Zn-induced reductive cross-coupling copolymerization of two nitrobenzene-like building blocks with different 'internal molecular free volumes' (IMFVs), i.e., 2,7,14-trinitrotriptycene and 2,2',7,7'-tetranitro-9,9'-spirobifluorene, with different molar ratios. Increasing the content of spirobifluorene (SBF) segments with a smaller IMFV relative to that of triptycene leads to an unconventional rise-fall pattern in porosity. Unlike most reported porous copolymers whose surface area lies between the corresponding homopolymers, the copolymer NOP-34@7030 with 30% SBF segments unprecedentedly shows the largest Brunauer-Emmett-Teller specific surface area (up to 823 m(2) g(-1)) as well as promoted CO2 uptake abilities (from 2.31 to 3.22 mmol g(-1), at 273 K/1.0 bar). The 100% triptycene(TPC)-derived homopolymer (NOP-34@1000) with a moderate surface area shows the highest CO2/N2 IAST selectivity of 109 (273 K) among the five samples, surpassing most known nanoporous organic polymers. This may contribute significantly to our understanding of the relationship of IMFVs with the properties of copolymerized materials. PMID:27054609

  11. The Effect of Inorganic Salt to the Competitive Adsorption Properties between Sulfate and Polycarboxylate Superplasticizer%无机盐对硫酸盐与聚羧酸减水剂相互作用的影响

    Institute of Scientific and Technical Information of China (English)

    刘娟红; 高霞; 纪洪广

    2013-01-01

    The purpose of this paper is to explore the effect mechanism of sulfate salt on polycarboxylate superplasticizer dispersion and to improve the sulfate adsorption properties of polycarboxylate superplasticizer.Fly ash is incorporated into the predetermined mass ratio of sodium sulfate to change mass fraction of sulfate,then adding inorganic salts in the sulfate-polycarboxylate system through the total content of organic carbon(TOC),ζ potential as well as infrared spectrum experiment.The results show that when the sulfate content in fly ash is 3 %,add in 3 % barium nitrate,organic carbon content of the admixture solution increased from 898 mg/L to 914 mg/L,zeta potential absolute value was increased from 11.11 mV to 14.6 mV;add in 3 % calcium chloride additive solution,organic carbon content increased from 898 mg/L to 1 141 mg/L,zeta potential absolute value was increased from 11.11 mV to15.91 mV;At the same time when the sulfate content in fly ash is 3 %,the percentage of transmittance in the infrared spectrum decreased,but inorganic salt(3% barium nitrate or 3% calcium chloride)is added to the system,the percentage transmittance in the IR greatly improved.The conclusion is that inherent interaction is existed between sodium and polycarboxylate superplasticizer.The higher the sodium mass fraction in fly ash,the greater the amount adsorption of polycarboxylate superplasticizer adsorption,and join in orgainic salt in the system of Sulfate and polycarboxylate can weaken the impact of sulfate on the adsorption properties of polycarboxylate superplasticizer.%目的 探讨硫酸盐对聚羧酸减水剂分散效果的影响机理,改善硫酸盐对聚羧酸减水剂吸附性能的影响.方法 在粉煤灰中掺入硫酸钠以改变其体系中硫酸盐的含量,然后在硫酸盐-聚羧酸体系中加入无机盐,采用总有机碳质量浓度(TOC)、ζ电位以及红外光谱等试验.结果 当粉煤灰中硫酸钠质量分数为3%时,加入3%的硝酸

  12. Copper adsorption in tropical oxisols

    Directory of Open Access Journals (Sweden)

    Silveira Maria Lucia Azevedo

    2003-01-01

    Full Text Available Cu adsorption, at concentrations between 0 to 800 mg L-1, was evaluated in surface and subsurface samples of three Brazilian soils: a heavy clayey-textured Rhodic Hapludalf (RH, a heavy clayey-textured Anionic ''Rhodic'' Acrudox (RA and a medium-textured Anionic ''Xanthic'' Acrudox (XA. After adsorption, two consecutive extractions were performed to the samples which received 100 mg L-1 copper. Surface samples adsorbed higher amounts of Cu than the subsurface, and exhibited lower Cu removed after the extractions, reinforcing the influence of the organic matter in the reactions. Cu adsorption was significant in the subsurface horizons of the Oxisols, despite the positive balance of charge, demonstrating the existence of mechanisms for specific adsorption, mainly related to the predominance of iron and aluminum oxides in the mineral fractions. In these samples, Cu was easily removed from the adsorption sites. RH demonstrated a higher capacity for the Cu adsorption in both horizons.

  13. Chromium (VI) adsorption on boehmite

    Energy Technology Data Exchange (ETDEWEB)

    Granados-Correa, F. [Instituto Nacional de Investigaciones Nucleares, Apartado Postal 18-1027 Col., Escandon, Delegacion Miguel Hidalgo, C.P. 11801 Mexico, D.F. (Mexico)], E-mail: fgc@nuclear.inin.mx; Jimenez-Becerril, J. [Instituto Nacional de Investigaciones Nucleares, Apartado Postal 18-1027 Col., Escandon, Delegacion Miguel Hidalgo, C.P. 11801 Mexico, D.F. (Mexico)

    2009-03-15

    Boehmite was synthesized and characterized in order to study the adsorption behavior and the removal of Cr(VI) ions from aqueous solutions as a function of contact time, initial pH solution, amount of adsorbent and initial metal ion concentration, using batch technique. Adsorption data of Cr(VI) on the boehmite were analyzed according to Freundlich, Langmuir and Dubinin-Radushkevich (D-R) adsorption models. Thermodynamic parameters for the adsorption system were determinated at 293, 303, 313 and 323 K temperatures. The kinetic values and thermodynamic parameters from the adsorption process show that the Cr(VI) ions adsorption on boehmite is an endothermic and spontaneous process. These results show that the boehmite could be considered as a potential adsorbent for chromium ions in aqueous solutions.

  14. Adsorption Model for Off-Gas Separation

    Energy Technology Data Exchange (ETDEWEB)

    Veronica J. Rutledge

    2011-03-01

    The absence of industrial scale nuclear fuel reprocessing in the U.S. has precluded the necessary driver for developing the advanced simulation capability now prevalent in so many other countries. Thus, it is essential to model complex series of unit operations to simulate, understand, and predict inherent transient behavior and feedback loops. A capability of accurately simulating the dynamic behavior of advanced fuel cycle separation processes will provide substantial cost savings and many technical benefits. The specific fuel cycle separation process discussed in this report is the off-gas treatment system. The off-gas separation consists of a series of scrubbers and adsorption beds to capture constituents of interest. Dynamic models are being developed to simulate each unit operation involved so each unit operation can be used as a stand-alone model and in series with multiple others. Currently, an adsorption model has been developed in gPROMS software. Inputs include gas stream constituents, sorbent, and column properties, equilibrium and kinetic data, and inlet conditions. It models dispersed plug flow in a packed bed under non-isothermal and non-isobaric conditions for a multiple component gas stream. The simulation outputs component concentrations along the column length as a function of time from which the breakthrough data is obtained. It also outputs temperature along the column length as a function of time and pressure drop along the column length. Experimental data will be input into the adsorption model to develop a model specific for iodine adsorption on silver mordenite as well as model(s) specific for krypton and xenon adsorption. The model will be validated with experimental breakthrough curves. Another future off-gas modeling goal is to develop a model for the unit operation absorption. The off-gas models will be made available via the server or web for evaluation by customers.

  15. Adsorption Model for Off-Gas Separation

    International Nuclear Information System (INIS)

    The absence of industrial scale nuclear fuel reprocessing in the U.S. has precluded the necessary driver for developing the advanced simulation capability now prevalent in so many other countries. Thus, it is essential to model complex series of unit operations to simulate, understand, and predict inherent transient behavior and feedback loops. A capability of accurately simulating the dynamic behavior of advanced fuel cycle separation processes will provide substantial cost savings and many technical benefits. The specific fuel cycle separation process discussed in this report is the off-gas treatment system. The off-gas separation consists of a series of scrubbers and adsorption beds to capture constituents of interest. Dynamic models are being developed to simulate each unit operation involved so each unit operation can be used as a stand-alone model and in series with multiple others. Currently, an adsorption model has been developed in gPROMS software. Inputs include gas stream constituents, sorbent, and column properties, equilibrium and kinetic data, and inlet conditions. It models dispersed plug flow in a packed bed under non-isothermal and non-isobaric conditions for a multiple component gas stream. The simulation outputs component concentrations along the column length as a function of time from which the breakthrough data is obtained. It also outputs temperature along the column length as a function of time and pressure drop along the column length. Experimental data will be input into the adsorption model to develop a model specific for iodine adsorption on silver mordenite as well as model(s) specific for krypton and xenon adsorption. The model will be validated with experimental breakthrough curves. Another future off-gas modeling goal is to develop a model for the unit operation absorption. The off-gas models will be made available via the server or web for evaluation by customers.

  16. ADSORPTION OF PHENOL IN NON—AQUEOUS SYSTEM BASED ON HYDROGEN—BONDING

    Institute of Scientific and Technical Information of China (English)

    XUMancai; SHIZuoqing; 等

    2000-01-01

    Two hydrogen-bonding adsorbents-macroporous crosslinked poly(P-nitrostyrene)and poly(p-vinylbenzyl amide)-were synthesized,and the adsorption property of phenol from cyclohexane solution onto the adsorbents was studied,The differential adsorption heasts for varied adsorption capacities calculated from the adsorption isotherms according to the Claperyron-Clausius equation lay in the range of hydrogen bond energy (8-50kJ/mol),The adsorption capaccity of o-nitrophenol in cyclohexane was moch less than that of phenol under the same condition.The adsorption capacity of phenol from cyclohexane onto polyacrylonitrile was much less than that onto poly(p-nitrostyrene)or poly(p-vinylbenzyl amide),All these results revealed that adsorption of phenol from cyclohexane by poly(p-nitrostyrene) or poly(p-vinylbenzyl amide)is based on hydrogen-bonding.

  17. Adsorption of Pb(II by Activated Pyrolytic Char from Used Tire

    Directory of Open Access Journals (Sweden)

    Lu Ping

    2016-01-01

    Full Text Available As a renewable resource, the pyrolytic char derived from used tire has promising adsorption capacities owing to its similar structure and properties with active carbon. The purification and activation of the pyrolytic char from used tire, as well as the application of this material in the adsorption of Pb(II in water is conducted. The influences on the adsorption capacity by temperature and pH value are investigated and discussed; the adsorption thermodynamics and kinetics are also studied. The results show that the pyrolytic char from used tire has remarkable adsorption capacity for Pb(II, and the adsorption is an endothermic process complying with the Langmuir isotherm. The adsorption kinetics is a pseudo second-order reaction.

  18. Adsorption studies on ground shells of hazelnut and almond.

    Science.gov (United States)

    Bulut, Yasemin; Tez, Zeki

    2007-10-01

    Adsorption behaviour of Ni(II), Cd(II) and Pb(II) from aqueous solutions by shells of hazelnut and almond were investigated. The structural properties and surface chemistry of the shells were characterized using sorption of nitrogen and Boehm titration. The equilibrium time was found to be 120 min. The equilibrium adsorption capacity of shells were obtained by using linear Langmuir and Freundlich adsorption isotherms. The equilibrium adsorption level was determined to be a function of the solution contact time, concentration and temperature. The thermodynamic parameters have been determined. The negative values of free change (DeltaG) indicated the spontaneous nature of the adsorption of Ni(II), Cd(II) and Pb(II) onto shells of hazelnut and almond and the positive values of enthalpy change (DeltaH) suggested the endothermic nature of the adsorption process. The best correlation coefficients were obtained for the pseudo second-order kinetic model. Ion exchange is probably one of the major adsorption mechanisms for binding divalent metal ions to the shells of hazelnut and almond. The selectivity order of the adsorbents is Pb(II)>Cd(II)>Ni(II). PMID:17467899

  19. Adsorption of ammonia on treated stainless steel and polymer surfaces

    Science.gov (United States)

    Vaittinen, O.; Metsälä, M.; Persijn, S.; Vainio, M.; Halonen, L.

    2014-05-01

    Adsorption of dynamically diluted ammonia at part-per-billion to low part-per-million concentrations in dry nitrogen was studied with treated and non-treated stainless steel and polymer test tubes. The treatments included electropolishing and two types of coatings based on amorphous silicon. Cavity ring-down spectroscopy with an external cavity diode laser operating in the near-infrared wavelength range was used to monitor the adsorption process in real time in continuous-flow conditions to obtain quantitative assessment of the adsorptive properties of the studied surfaces. The investigated polymers were all less adsorptive than any of the treated or non-treated stainless steel surfaces. Some of the commercial coatings reduced the adsorption loss of stainless steel by a factor of ten or more. Polyvinylidene fluoride was found to be superior (less adsorption) to the four other studied polymer coatings. The number of adsorbed ammonia molecules per surface area obtained at different ammonia gas phase concentrations was modeled with Langmuir and Freundlich isotherms. The time behavior of the adsorption-desorption process occurring in the time scale of seconds and minutes was simulated with a simple kinetic model.

  20. Adsorption and collective paramagnetism

    CERN Document Server

    Selwood, Pierce W

    1962-01-01

    Adsorption and Collective Paramagnetism describes a novel method for studying chemisorption. The method is based on the change in the number of unpaired electrons in the adsorbent as chemisorption occurs. The method is applicable to almost all adsorbates, but it is restricted to ferromagnetic adsorbents such as nickel, which may be obtained in the form of very small particles, that is to say, to ferromagnetic adsorbents with a high specific surface. While almost all the data used illustratively have been published elsewhere this is the first complete review of the subject. The book is addresse

  1. Study of plutonium adsorption by fibrous adsorbent

    International Nuclear Information System (INIS)

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

  2. Advanced adsorption cooling cum desalination cycle: A thermodynamic framework

    KAUST Repository

    Chakraborty, Anutosh

    2011-01-01

    We have developed a thermodynamic framework to calculate adsorption cooling cum desalination cycle performances as a function of pore widths and pore volumes of highly porous adsorbents, which are formulated from the rigor of thermodynamic property surfaces of adsorbent-adsorbate system and the adsorption interaction potential between them. Employing the proposed formulations, the coefficient of performance (COP) and overall performance ratio (OPR) of adsorption cycle are computed for various pore widths of solid adsorbents. These results are compared with experimental data for verifying the proposed thermodynamic formulations. It is found from the present analysis that the COP and OPR of adsorption cooling cum desalination cycle is influenced by (i) the physical characteristics of adsorbents, (ii) characteristics energy and (iii) the surface-structural heterogeneity factor of adsorbent-water system. The present study confirms that there exists a special type of adsorbents having optimal physical characteristics that allows us to obtain the best performance.

  3. Adsorption of inorganic anionic contaminants on surfactant modified minerals

    Directory of Open Access Journals (Sweden)

    MAGDALENA TOMASEVIC-CANOVIC

    2003-11-01

    Full Text Available Organo-mineral complexes were obtained by treatment of aluminosilicate minerals (zeolite, bentonite and diatomaceous earth with a primary amine (oleylamine and an alkyl ammonium salt (stearyldimethylbenzyl ammonium chloride. The modification of the zeolite surface was carried out in two steps. The first step was treatment of the zeolite with 2 M HCl. This acid treatment of the zeolite increased its affinity for neutral molecules such as surface-active amines. The second step of the modification was the adsorption of oleylamine on the acid treated zeolite. Four types of organo-mineral complexes were prepared and their anion adsorption properties were compared to those of organo-zeolite. The adsorption of sulphate, bichromate and dihydrogenphosphate anions on the organo-mineral complexes was investigated. The anion adsorption measurements showed that the most efficient adsorbent for anion water pollutants was the primary amine modified H+-form zeolite.

  4. Adsorption phenomena and anchoring energy in nematic liquid crystals

    CERN Document Server

    Barbero, Giovanni

    2005-01-01

    Despite the large quantity of phenomenological information concerning the bulk properties of nematic phase liquid crystals, little is understood about the origin of the surface energy, particularly the surface, interfacial, and anchoring properties of liquid crystals that affect the performance of liquid crystal devices. Self-contained and unique, Adsorption Phenomena and Anchoring Energy in Nematic Liquid Crystals provides an account of new and established results spanning three decades of research into the problems of anchoring energy and adsorption phenomena in liquid crystals.The book contains a detailed discussion of the origin and possible sources of anchoring energy in nematic liquid crystals, emphasizing the dielectric contribution to the anchoring energy in particular. Beginning with fundamental surface and anchoring properties of liquid crystals and the definition of the nematic phase, the authors explain how selective ion adsorption, dielectric energy density, thickness dependence, and bias voltage...

  5. Comparative study of cesium adsorption on dioctahedral and trioctahedral smectites

    International Nuclear Information System (INIS)

    Bentonites which are characterized by good rheological, mineralogical and chemical stability is considered used as sealing barriers in multibarrier Slovak system of deep geological repository for high-level radioactive waste and spent nuclear fuel. In Slovak Republic there are several significant deposits of bentonite, which are characterized by appropriate adsorption properties and meet the geotechnical requirements for this type of barriers. Study of adsorption properties of bentonites and other smectites is an essential step for developing the migration model long-lived corrosion and activation products, and fission products of uranium. Nuclear wastes contain the most important nuclear fission products, radioisotopes 134Cs and 137Cs. The present paper investigates and compares the cesium adsorption properties of Slovak and North America bentonites composed mainly of dioctahedral smectite montmorillonite (J, L, SAz-1 and STx-1) and trioctahedral smectites saponite (SapCa-2) and hectorite (SHCa-1). (author)

  6. Adsorptive removal of Cu(II) from aqueous solutions using collagen-tannin resin

    Energy Technology Data Exchange (ETDEWEB)

    Sun Xia; Huang Xin [Department of Biomass Chemistry and Engineering, Sichuan University, Chengdu 610065 (China); Liao Xuepin, E-mail: xpliao@scu.edu.cn [Department of Biomass Chemistry and Engineering, Sichuan University, Chengdu 610065 (China); National Engineering Laboratory for Clean Technology of Leather Manufacture, Sichuan University, Chengdu 610065 (China); Shi Bi, E-mail: shibi@scu.edu.cn [National Engineering Laboratory for Clean Technology of Leather Manufacture, Sichuan University, Chengdu 610065 (China)

    2011-02-28

    The collagen-tannin resin (CTR), as a novel adsorbent, was prepared via a reaction of collagen with black wattle tannin and aldehyde, and its adsorption properties to Cu(II) were systematically investigated, including pH effect, adsorption equilibrium, adsorption kinetics, and column adsorption. The adsorption capacity of Cu(II) on CTR was pH-dependent, and it increased with the increase of solution pH. The adsorption isotherms were well described by Langmuir isotherm model with correlating constant (R{sup 2}) higher than 0.99. The adsorption capacity determined at 303 K was high up to 0.26 mmol/g, which was close to the value (0.266 mmol/g) estimated from Langmuir equation. The adsorption capacity was increased with the increase of temperature, and thermodynamic calculations suggested that the adsorption of Cu(II) on CTR is an endothermic process. The adsorption kinetics were well fitted by the pseudo-second-order rate model. Further column studies suggested that CTR was effective for the removal of Cu(II) from solutions, and more than 99% of Cu(II) was desorbed from column using 0.1 mol/L HNO{sub 3} solution. The CTR column can be reused to adsorb Cu(II) without any loss of adsorption capacity.

  7. Adsorptive removal of Cu(II) from aqueous solutions using collagen-tannin resin

    International Nuclear Information System (INIS)

    The collagen-tannin resin (CTR), as a novel adsorbent, was prepared via a reaction of collagen with black wattle tannin and aldehyde, and its adsorption properties to Cu(II) were systematically investigated, including pH effect, adsorption equilibrium, adsorption kinetics, and column adsorption. The adsorption capacity of Cu(II) on CTR was pH-dependent, and it increased with the increase of solution pH. The adsorption isotherms were well described by Langmuir isotherm model with correlating constant (R2) higher than 0.99. The adsorption capacity determined at 303 K was high up to 0.26 mmol/g, which was close to the value (0.266 mmol/g) estimated from Langmuir equation. The adsorption capacity was increased with the increase of temperature, and thermodynamic calculations suggested that the adsorption of Cu(II) on CTR is an endothermic process. The adsorption kinetics were well fitted by the pseudo-second-order rate model. Further column studies suggested that CTR was effective for the removal of Cu(II) from solutions, and more than 99% of Cu(II) was desorbed from column using 0.1 mol/L HNO3 solution. The CTR column can be reused to adsorb Cu(II) without any loss of adsorption capacity.

  8. Contribution of Ash Content Related to Methane Adsorption Behaviors of Bituminous Coals

    Directory of Open Access Journals (Sweden)

    Yanyan Feng

    2014-01-01

    Full Text Available Methane adsorption isotherms on coals with varying ash contents were investigated. The textural properties were characterized by N2 adsorption/desorption isotherm at 77 K, and methane adsorption characteristics were measured at pressures up to 4.0 MPa at 298 K, 313 K, and 328 K, respectively. The Dubinin-Astakhov model and the Polanyi potential theory were employed to fit the experimental data. As a result, ash content correlated strongly to methane adsorption capacity. Over the ash range studied, 9.35% to 21.24%, the average increase in methane adsorption capacity was 0.021 mmol/g for each 1.0% rise in ash content. With the increasing ash content range of 21.24%~43.47%, a reduction in the maximum adsorption capacities of coals was observed. In addition, there was a positive correlation between the saturated adsorption capacity and the specific surface area and micropore volume of samples. Further, this study presented the heat of adsorption, the isosteric heat of adsorption, and the adsorbed phase specific heat capacity for methane adsorption on various coals. Employing the proposed thermodynamic approaches, the thermodynamic maps of the adsorption processes of coalbed methane were conducive to the understanding of the coal and gas simultaneous extraction.

  9. The adsorption behavior of functional particles modified by polyvinylimidazole for Cu(II) ion

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Ruixin; Men, Jiying; Gao, Baojiao [School of Chemical Engineering and Environment, North University of China, Taiyuan (China)

    2012-03-15

    In this paper, a novel composite material the silica grafted by poly(N-vinyl imidazole) (PVI), i.e., PVI/SiO{sub 2}, was prepared using 3-methacryloxypropyl trimethoxysilane (MPS) as intermedia through the ''grafting from'' method. The adsorption behavior of metal ions by PVI/SiO{sub 2} was researched by both static and dynamic methods. Experimental results showed that PVI/SiO{sub 2} possessed very strong adsorption ability for metal ions. For different metal ions, PVI/SiO{sub 2} exhibited different adsorption abilities with the following order of adsorption capacity: Cu{sup 2+}> Cd{sup 2+}> Zn{sup 2+}. The adsorption material PVI/SiO{sub 2} was especially good at adsorbing Cu(II) ion and the saturated adsorption capacity could reach up to 49.2 mg/g. The empirical Freundlich isotherm was found to describe well the equilibrium adsorption data. Higher temperatures facilitated the adsorption process and thus increased the adsorption capacity. The pH and grafting amount of PVI had great influence on the adsorption amount. In addition, PVI/SiO{sub 2} particles had excellent eluting and regenerating property using diluted hydrochloric acid solution as eluent. The adsorption ability trended to steady during 10 cycles. (Copyright copyright 2012 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  10. Effects of copper and aluminum on the adsorption of sulfathiazole and tylosin on peat and soil

    International Nuclear Information System (INIS)

    Effects of copper (Cu) and aluminum (Al) on the adsorption of sulfathiazole (STZ) and tylosin (T) to peat and soil were investigated using a batch equilibration method. Results show that Cu suppressed STZ adsorption onto peat and soil at pH 5.0 due to the formation of STZ–Cu complexes and/or Cu bridge. In contrast, Al only decreased STZ adsorption at pH 6.0. As for T, both Cu and Al suppressed its adsorption over the entire pH range owing to three reasons: 1) electrostatic competition between Cu/Al and T+; 2) Cu/Al adsorption made the soil and peat surface less negatively charged, which was unfavorable for T+ adsorption; 3) the shrunken pore size of peat and soil retarded the diffusion of large-sized T into these pores. -- Highlights: • Cu decreases STZ adsorption at pH 5.0. • Al decreases STZ adsorption at pH 6.0. • Cu and Al suppress T adsorption. • Cu and Al change partial properties of peat and soil. -- Cu and Al changed the adsorption behavior of STZ and T in soil and peat via complexation and/or change in partial properties of peat and soil

  11. Adsorption of oxazole and isoxazole on BNNT surface: A DFT study

    International Nuclear Information System (INIS)

    Highlights: • The adsorption of oxazole and isoxazole over (6,0) and (5,5) BNNTs is studied. • The adsorption energies and structural changes are inductive of covalent adsorption. • The solvent plays an important role in improving the adsorption properties. • The adsorption witnesses substantial changes in electronic properties of the BNNT. • The functionalization of the BNNTs open up their applicability as drug carrier. - Abstract: The adsorption behavior of oxazole and isoxazole heterocycles over the (6,0) zigzag and (5,5) armchair boron nitride nanotube (BNNT) has been studied within the formalism of density functional theory (DFT). The adsorption energies, the frontier molecular orbital (FMO) analysis and the structural changes at the adsorption site are indicative of covalent adsorption on the zigzag BNNT surface, while the adsorption is physical in nature on the armchair BNNT surface. The role of solvent in improving the adsorption properties over the BNNT surface is elucidated by reoptimizing the structures in aqueous phase. The solvation energy is indicative of remarkable increase in the solubility of BNNTs after adsorption of heterocyclic rings. The Density of states (DOS) Plots, natural bond orbital (NBO) analysis and the quantum molecular descriptors (QMD) are witness to the substantial changes in the electronic properties of the BNNT systems following the attachment of these heterocycles with the tube surface. The study envisages the functionalization of the BNNT as well as its applicability as carrier of the drugs containing heterocyclic rings oxazole and isoxazole with marked sensitivity to the type of adsorbate and the adsorbent

  12. Adsorption and STM imaging of tetracyanoethylene on Ag(001): An ab-initio study

    OpenAIRE

    Deilmann, Thorsten; Krüger, Peter; Rohlfing, Michael; Wegner, Daniel

    2016-01-01

    We investigate the adsorption of a single tetracyanoethylene (TCNE) molecule on the silver (001) surface. Adsorption structures, electronic properties, and scanning tunneling microscopy (STM) images are calculated within density-functional theory. Adsorption occurs most favorably in on-top configuration, with the C=C double bond directly above a silver atom and the four N atoms bound to four neighboring Ag atoms. The lowest unoccupied molecular orbital of TCNE becomes occupied due to electron...

  13. Adsorption of oxazole and isoxazole on BNNT surface: A DFT study

    Energy Technology Data Exchange (ETDEWEB)

    Kaur, Jasleen, E-mail: jasleen.chem@gmail.com; Singla, Preeti, E-mail: preetisingla21@gmail.com; Goel, Neetu, E-mail: neetugoel@pu.ac.in

    2015-02-15

    Highlights: • The adsorption of oxazole and isoxazole over (6,0) and (5,5) BNNTs is studied. • The adsorption energies and structural changes are inductive of covalent adsorption. • The solvent plays an important role in improving the adsorption properties. • The adsorption witnesses substantial changes in electronic properties of the BNNT. • The functionalization of the BNNTs open up their applicability as drug carrier. - Abstract: The adsorption behavior of oxazole and isoxazole heterocycles over the (6,0) zigzag and (5,5) armchair boron nitride nanotube (BNNT) has been studied within the formalism of density functional theory (DFT). The adsorption energies, the frontier molecular orbital (FMO) analysis and the structural changes at the adsorption site are indicative of covalent adsorption on the zigzag BNNT surface, while the adsorption is physical in nature on the armchair BNNT surface. The role of solvent in improving the adsorption properties over the BNNT surface is elucidated by reoptimizing the structures in aqueous phase. The solvation energy is indicative of remarkable increase in the solubility of BNNTs after adsorption of heterocyclic rings. The Density of states (DOS) Plots, natural bond orbital (NBO) analysis and the quantum molecular descriptors (QMD) are witness to the substantial changes in the electronic properties of the BNNT systems following the attachment of these heterocycles with the tube surface. The study envisages the functionalization of the BNNT as well as its applicability as carrier of the drugs containing heterocyclic rings oxazole and isoxazole with marked sensitivity to the type of adsorbate and the adsorbent.

  14. Liquid-Phase Adsorption Fundamentals.

    Science.gov (United States)

    Cooney, David O.

    1987-01-01

    Describes an experiment developed and used in the unit operations laboratory course at the University of Wyoming. Involves the liquid-phase adsorption of an organic compound from aqueous solution on activated carbon, and is relevant to adsorption processes in general. (TW)

  15. Enhancement of CO2 Adsorption and Catalytic Properties by Fe-Doping of [Ga2(OH)2(L)] (H4L = Biphenyl-3,3′,5,5′-tetracarboxylic Acid), MFM-300(Ga2)

    Science.gov (United States)

    2016-01-01

    Metal–organic frameworks (MOFs) are usually synthesized using a single type of metal ion, and MOFs containing mixtures of different metal ions are of great interest and represent a methodology to enhance and tune materials properties. We report the synthesis of [Ga2(OH)2(L)] (H4L = biphenyl-3,3′,5,5′-tetracarboxylic acid), designated as MFM-300(Ga2), (MFM = Manchester Framework Material replacing NOTT designation), by solvothermal reaction of Ga(NO3)3 and H4L in a mixture of DMF, THF, and water containing HCl for 3 days. MFM-300(Ga2) crystallizes in the tetragonal space group I4122, a = b = 15.0174(7) Å and c = 11.9111(11) Å and is isostructural with the Al(III) analogue MFM-300(Al2) with pores decorated with −OH groups bridging Ga(III) centers. The isostructural Fe-doped material [Ga1.87Fe0.13(OH)2(L)], MFM-300(Ga1.87Fe0.13), can be prepared under similar conditions to MFM-300(Ga2) via reaction of a homogeneous mixture of Fe(NO3)3 and Ga(NO3)3 with biphenyl-3,3′,5,5′-tetracarboxylic acid. An Fe(III)-based material [Fe3O1.5(OH)(HL)(L)0.5(H2O)3.5], MFM-310(Fe), was synthesized with Fe(NO3)3 and the same ligand via hydrothermal methods. [MFM-310(Fe)] crystallizes in the orthorhombic space group Pmn21 with a = 10.560(4) Å, b = 19.451(8) Å, and c = 11.773(5) Å and incorporates μ3-oxo-centered trinuclear iron cluster nodes connected by ligands to give a 3D nonporous framework that has a different structure to the MFM-300 series. Thus, Fe-doping can be used to monitor the effects of the heteroatom center within a parent Ga(III) framework without the requirement of synthesizing the isostructural Fe(III) analogue [Fe2(OH)2(L)], MFM-300(Fe2), which we have thus far been unable to prepare. Fe-doping of MFM-300(Ga2) affords positive effects on gas adsorption capacities, particularly for CO2 adsorption, whereby MFM-300(Ga1.87Fe0.13) shows a 49% enhancement of CO2 adsorption capacity in comparison to the homometallic parent material. We thus report herein the

  16. Theoretical investigation of OCN− adsorption onto boron nitride nanotubes

    International Nuclear Information System (INIS)

    Highlights: ► Adsorption behavior of OCN− on (6, 0) and (8, 0) BNNTs based on density functional theory. ► OCN− is strongly bound to BNNTs in corresponding configurations. ► The effect of the OCN− adsorption on the geometries and electronic properties of related BNNTs is investigated. ► BNNTs is suggested as superior sensor for OCN− comparing with CNTs. - Abstract: First-principles calculations based on density functional theory (DFT) method are used to investigate the adsorption properties of OCN− on H-capped zigzag and armchair single-walled BN nanotubes (BNNTs). The results indicate that OCN− is strongly bound to the outer surface of zigzag (6, 0) BNNTs in comparison with armchair (5, 5) BNNT. Binding energy and equilibrium distance corresponding to the most stable configuration are found to be −486.79 kJ mol−1 and 1.526 Å, respectively being typical for the chemisorptions. Energy gap, dipole moment, natural atomic orbital occupancies and global indices for most stable configuration are calculated. Furthermore, the effect of the OCN− adsorption on the geometries and electronic properties of related BNNT is also studied. The calculated density of states (DOS) reveals that there is a significant orbital hybridization between two species in adsorption process being an evidence of strong interaction. Therefore, one can conclude that BNNTs play an important role as suitable sensor.

  17. Adsorption and co-adsorption of diclofenac and Cu(II) on calcareous soils.

    Science.gov (United States)

    Graouer-Bacart, Mareen; Sayen, Stéphanie; Guillon, Emmanuel

    2016-02-01

    Pharmaceuticals are emerging contaminants and their presence in different compartments of the environment has been detected in many countries. In this study, laboratory batch experiments were conducted to characterize the adsorption of diclofenac, a widely used non-steroidal anti-inflammatory drug, on six calcareous soils. The adsorption of diclofenac was relatively low, which may lead to a risk of groundwater contamination and plant uptake. A correlation between the soil-water distribution coefficient Kd and soil characteristics has been highlighted. Indeed, diclofenac adsorption as a function of soil organic matter content (% OM) and Rt=% CaCO3/% OM was successfully described through a simple empirical model, indicating the importance of considering the inhibiting effect of CaCO3 on OM retention properties for a better assessment of diclofenac fate in the specific case of calcareous soils. The simultaneous co-adsorption of diclofenac and copper - a ubiquitous pollutant in the environment - at the water/soil interface, was also investigated. It appeared quite unexpectedly that copper did not have a significant influence on diclofenac retention. PMID:26599281

  18. Hydrogen adsorption in metal-organic frameworks

    International Nuclear Information System (INIS)

    Metal-Organic Frameworks (MOFs) have recently received considerable attention because of their high specific micropore volume and the ability to store gas molecules exceeding the storage capacity of traditional adsorbents. A variety of differences in the MOFs structures makes it difficult to analyze the influence of different factors on hydrogen uptake capabilities in MOFs. We have investigated the influence of the minor structural changes of the MOFs on their hydrogen storage capacity. The influence of the incorporated metal was shown for following isostructural compounds: Cu3(BTC)2 (BTC=1,3,5-benzenetricarboxylate) and Mo3(BTC)2; Zn2(BDC)2DABCO and Co2(BDC)2DABCO (BDC=1,4-benzenedicarboxylate, DABCO=1,4-diazabicyclo[2.2.2]octane). Our research interest is directed also towards the discovery of new MOFs, as well as adjusting the pore dimensions of MOFs, using different building blocks, solvent and solvent mixtures, in order to improve gas uptake and adsorption properties. Magnesium-based MOFs were found with the same network topology, very small pore size and selective adsorption behaviour. They show a guest-induced reversible structure transformation due to the flexibility of the Mg3-cluster and the organic linkers. This effect could be used for fitting the pore sizes and for the increase of gas sorption capability in Mg contained MOFs after all. The hydrogen adsorption was also studied in several Al-based IRMOFs

  19. Adsorption of Cs-137 and U-238 in semi-arid soils

    International Nuclear Information System (INIS)

    Is of great importance to determine the adsorption properties of the soils where radioactive wastes are stored, fundamentally of the radioisotopes contained in these wastes, with the purpose of knowing like will be their behavior in the event of happening radionuclide migration toward the surrounding means. Therefore, in this work the adsorption properties of 137Cs+ and 238UO22+ in soils coming from the Storage Center of Radioactive Wastes are studied. Was studied the effect of the soil type and the particle size of the soil in the adsorption properties of Cs (I) and U (Vi). 13 soil samples and six different particle sizes were analyzed. The adsorption studies were carried out by the radiotracers technique in static way. The results indicate an important adsorption affinity toward the Cs-137 and a very vulnerable affinity for the 238UO22+. (author)

  20. Evaluation of the Adsorption Performance and Sustainability of Exfoliated Graphite Nanoplatelets (xGnP for VOCs

    Directory of Open Access Journals (Sweden)

    Seong Jin Chang

    2015-11-01

    Full Text Available Exfoliated graphite nanoplatelets (xGnP, which combine the layered structure and low price of nanoclays with the superior mechanical, electrical, and thermal properties of carbon nanotubes, are very cost-effective, and can simultaneously provide a multitude of physical and chemical property enhancements. In this study, we evaluated xGnP’s adsorption performance of volatile organic compounds (VOCs according to thermal extractor (TE analysis for seven days in order to use the xGnP as an adsorption material of pollutants. In addition, we carried out a sustainability evaluation in order to evaluate its adsorption capacity over 28 days. The results indicate that the adsorption performance of xGnP is higher than for other adsorption materials such as zeolite. Also, we determined that the adsorption performance of xGnP is maintained continuously for 28 days and that its adsorption capacity is large.

  1. Pulse gas chromatographic study of adsorption of substituted aromatics and heterocyclic molecules on MIL-47 at zero coverage.

    Science.gov (United States)

    Duerinck, Tim; Couck, Sarah; Vermoortele, Frederik; De Vos, Dirk E; Baron, Gino V; Denayer, Joeri F M

    2012-10-01

    The low coverage adsorptive properties of the MIL-47 metal organic framework toward aromatic and heterocyclic molecules are reported in this paper. The effect of molecular functionality and size on Henry adsorption constants and adsorption enthalpies of alkyl and heteroatom functionalized benzene derivates and heterocyclic molecules was studied using pulse gas chromatography. By means of statistical analysis, experimental data was analyzed and modeled using principal component analysis and partial least-squares regression. Structure-property relationships were established, revealing and confirming several trends. Among the molecular properties governing the adsorption process, vapor pressure, mean polarizability, and dipole moment play a determining role. PMID:22958218

  2. Adsorption of Atenolol on Kaolinite

    Directory of Open Access Journals (Sweden)

    Yingmo Hu

    2015-01-01

    Full Text Available In this study the adsorption of atenolol (AT, a β-blocker, on kaolinite, a clay mineral of low surface charge, was investigated under varying initial AT concentration, equilibrium time, solution pH, ionic strength, and temperature conditions. The results showed that the amounts of AT uptake by kaolinite were close to its cation exchange capacity value and the AT adsorption was almost instantaneous, suggesting a surface adsorption. The adsorption was exothermic and the free energy of adsorption was small negative, indicating physical adsorption. The increase in ionic strength of the solution drastically reduced AT uptake on kaolinite. A significant reduction in AT uptake was found at solution pH below 5 or above 10. The FTIR results showed band shifting and disappearance for NH bending vibration and benzene ring skeletal vibration at 3360 and 1515 cm−1 and band splitting at 1412 and 1240 cm−1 attributed to C–N valence vibration coupled with NH bending vibrations and alkyl aryl ether linkage, suggesting the participation of NH, –O–, and benzene ring for AT adsorption on kaolinite.

  3. Adsorption Desalination: A Novel Method

    KAUST Repository

    Ng, Kim Choon

    2010-11-15

    The search for potable water for quenching global thirst remains a pressing concern throughout many regions of the world. The demand for new and sustainable sources and the associated technologies for producing fresh water are intrinsically linked to the solving of potable water availability and hitherto, innovative and energy efficient desalination methods seems to be the practical solutions. Quenching global thirst by adsorption desalination is a practical and inexpensive method of desalinating the saline and brackish water to produce fresh water for agriculture irrigation, industrial, and building applications. This chapter provides a general overview of the adsorption fundamentals in terms of adsorption isotherms, kinetics, and heat of adsorption. It is then being more focused on the principles of thermally driven adsorption desalination methods. The recent developments of adsorption desalination plants and the effect of operating conditions on the system performance in terms of specific daily water production and performance ratio are presented. Design of a large commercial adsorption desalination plant is also discussed herein.

  4. Adsorption of polymeric brushes: Bridging

    Science.gov (United States)

    Johner, Albert; Joanny, Jean-François

    1992-04-01

    We study the adsorption of grafted polymer layers on a planar surface parallel to the grafting surface. The layer consists of two types of chains: nonadsorbed chains with a free end and adsorbed chains forming bridges between the two plates. In the limit of strong adsorption a dead zone exists in the vicinity of the adsorbing plate; its size increases with the adsorption strength. Two adsorption mechanisms are possible: adsorption of the last monomer only and adsorption of all the monomers. In both cases the adsorption regimes at equilibrium (when no external force acts on the plates) are discussed within the framework of the self-consistent mean-field theory. We also give scaling laws taking into account excluded volume correlations. Finally, we consider situations where a finite external force, either tangential or normal to the plates, is applied on the adsorbing plate. Pulling and tangential forces both reduce the fraction of bridges and eventually lead to rupture, whereas compressional forces favor bridging. For normal forces, force vs distance profiles between planes and crossed cylinders are given.

  5. Adsorption of Oxaliplatin by Hydroxyapatite

    Directory of Open Access Journals (Sweden)

    Papageorgiou A.

    2007-12-01

    Full Text Available Hydroxyapatite (HAP is the main inorganic component of human skeleton. The last years a lot of interest is focused on its use as drug carrier. In this work the in vitro adsorption of the anti-cancer drug oxaliplatin, by HAP, from its aqueous solution was studied. Various initial concentrations of oxaliplatin aqueous solutions were used in order to determine the maximum adsorption capacity of HAP. Oxaliplatin's concentrations were determined through Pt determinations by atomic absorption spectrometry with flame technique, in the equilibrated solutions after shaking for 48 hours and filtering the HAP-oxaliplatin slurries. The maximum adsorption capacity was found to be 49.1 mg oxaliplatin/g HAP. In order to determine the time needed for the maximum adsorption to be achieved, six oxaliplatin - HAP slurries were prepared. The slurries had initial oxaliplatin concentrations the one that corresponds to the maximum adsorption capacity of the HAP added. The oxaliplatin determination was carried out after 0, 10, 20, 30, 40 and 48 hours in each different slurry. The maximum adsorption capacity was achieved after 20 hours. The adsorption of oxaliplatin by HAP was found to follow the Freundlich equation.

  6. Highly efficient adsorption of chlorophenols onto chemically modified chitosan

    Science.gov (United States)

    Zhou, Liang-Chun; Meng, Xiang-Guang; Fu, Jing-Wei; Yang, Yu-Chong; Yang, Peng; Mi, Chun

    2014-02-01

    A novel chemically modified chitosan CS-SA-CD with phenol and β-cyclodextrin groups was prepared. The adsorptions of phenol, 2-chlorophenol (2-CP), 4-chlorophenol (4-CP), 2,4-dichlorophenol (DCP) and 2,4,6-trichlorophenol (TCP) on the functional chitosan from aqueous solution were investigated. CS-SA-CD exhibited excellent adsorption ability for chlorophenols especially for DCP and TCP. The maximum adsorption capacities of phenol, 2-CP, 4-CP, DCP and TCP on CS-SA-CD were 59.74, 70.52, 96.43, 315.46 and 375.94 mg/g, respectively. The scanning electron microscope and Brunauer-Emmett-Teller analyses revealed that the introduction of phenol group changed the surface morphology and surface properties of chitosan. The modified chitosan CS-SA-CD possesses larger surface areas (4.72 m2/g), pore volume (7.29 × 10-3 mL/g) and average pore diameter (59.99 Å) as compared to those of chitosan 3.27 m2/g, 2.00 × 10-3 mL/g and 15.95 Å, respectively. The enhanced adsorption of chlorophenols was also attributed to the interaction of hydrogen bond between Cl atom and sbnd OH group. The adsorption of chlorophenols on CS-SA-CD followed the pseudo-second-order kinetic model. Adsorbent could be regenerated easily and the regenerated CS-SA-CD remained 80-91% adsorption efficiency.

  7. Highly efficient adsorption of chlorophenols onto chemically modified chitosan

    International Nuclear Information System (INIS)

    A novel chemically modified chitosan CS-SA-CD with phenol and β-cyclodextrin groups was prepared. The adsorptions of phenol, 2-chlorophenol (2-CP), 4-chlorophenol (4-CP), 2,4-dichlorophenol (DCP) and 2,4,6-trichlorophenol (TCP) on the functional chitosan from aqueous solution were investigated. CS-SA-CD exhibited excellent adsorption ability for chlorophenols especially for DCP and TCP. The maximum adsorption capacities of phenol, 2-CP, 4-CP, DCP and TCP on CS-SA-CD were 59.74, 70.52, 96.43, 315.46 and 375.94 mg/g, respectively. The scanning electron microscope and Brunauer–Emmett–Teller analyses revealed that the introduction of phenol group changed the surface morphology and surface properties of chitosan. The modified chitosan CS-SA-CD possesses larger surface areas (4.72 m2/g), pore volume (7.29 × 10−3 mL/g) and average pore diameter (59.99 Å) as compared to those of chitosan 3.27 m2/g, 2.00 × 10−3 mL/g and 15.95 Å, respectively. The enhanced adsorption of chlorophenols was also attributed to the interaction of hydrogen bond between Cl atom and -OH group. The adsorption of chlorophenols on CS-SA-CD followed the pseudo-second-order kinetic model. Adsorbent could be regenerated easily and the regenerated CS-SA-CD remained 80–91% adsorption efficiency.

  8. ADSORPTION CHARACTERISTICS OF L-HISTIDINE ON ACTIVE CARBON

    Institute of Scientific and Technical Information of China (English)

    2005-01-01

    Adsorption properties of L-histidine on active carbon were studied in the paper, which are affected by the main parameters, such as the quantity percent of active carbon, pH value of the solution, the time of adsorption equilibrium and adsorption temperature. The results indicate that adsorption equilibrium time of L-his on active carbon is about 80 minutes. With the increasing of the quantity percent of active carbon, the adsorbance of L-his decreases sharply, and increases lighter after that. When the quantity percent of active carbon is 10%, the adsorbance reaches the minimum.pH value of solution and extraction temperature have great affection on the adsorption. When the pH value is higher or lower than the pI of L-his, the adsorbance is small, even zero. It is proven that the experimental equilibrium data which are obtained under the conditions of 80 ℃and pH=1.0, are fitted with the Freundlich equation: q=2.5914c0.8097. The results can provide certain references in L-his adsorption process of industrial operation.

  9. Adsorption of volatile hydrocarbons in iron polysulfide chalcogels

    KAUST Repository

    Ahmed, Ejaz

    2014-11-01

    We report the synthesis, characterization and possible applications of three new metal-chalcogenide aerogels KFe3Co3S 21, KFe3Y3S22 and KFe 3Eu3S22. Metal acetates react with the alkali metal polychalcogenides in formamide/water mixture to form extended polymeric frameworks that exhibit gelation phenomena. Amorphous aerogels obtained after supercritical CO2 drying have BET surface area from 461 to 573 m 2/g. Electron microscopy images and nitrogen adsorption measurements showed that pore sizes are found in micro (below 2 nm), meso (2-50 nm), and macro (above 50 nm) porous regions. These chalcogels possess optical bandgaps in the range of 1.55-2.70 eV. These aerogels have been studied for the adsorption of volatile hydrocarbons and gases. A much higher adsorption of toluene in comparison with cyclohexane and cyclopentane vapors have been observed. The adsorption capacities of the three volatile hydrocarbons are found in the following order: toluene > cyclohexane > cyclopentane. It has been observed that high selectivity in adsorption is feasible with high-surface-area metal chalcogenides. Similarly, almost an eight to ten times increase in adsorption selectivity towards CO2 over H2/CH4 was observed in the aerogels. Moreover, reversible ion-exchange properties for K+/Cs+ ions have also been demonstrated. © 2014 Elsevier Inc. All rights reserved.

  10. Adsorption of dyes onto activated carbon prepared from olive stones

    Institute of Scientific and Technical Information of China (English)

    Souad NAJAR-SOUISSI; Abdelmottaleb OUEDERNI; Abdelhamid RATEL

    2005-01-01

    Activated carbon was produced from olive stones(OSAC) by a physical process in two steps. The adsorption character of this activated carbon was tested on three colour dyes molecules in aqueous solution: Methylene blue(MB), Rhodamine B(RB) and Congo Red(CR). The adsorption equilibrium was studied through isotherms construction at 30℃, which were well described by Langmuir model.The adsorption capacity on the OSAC was estimated to be 303 mg/g, 217 mg/g and 167 mg/g respectively for MB, RB and CR. This activated carbon has a similar adsorption properties to that of commercial ones and show the same adsorption performances. The adsorption kinetics of the MB molecule in aqueous solution at different initial concentrations by OSAC was also studied. Kinetic experiments were well fitted by a simple intra-particle diffusion model. The measured kinetics constant was influenced by the initial concentration and we found the following correlation: Kid = 1.55 C00.51 .

  11. On thermodynamics of methane+carbonaceous materials adsorption

    KAUST Repository

    Rahman, Kazi Afzalur

    2012-01-01

    This study presents the theoretical frameworks for the thermodynamic quantities namely the heat of adsorption, specific heat capacity, entropy, and enthalpy for the adsorption of methane onto various carbonaceous materials. The proposed theoretical frameworks are developed from the rigor of thermodynamic property surfaces of a single component adsorbate-adsorbent system and by incorporating the micropore filling theory approach, where the effect of adsorbed phase volume is considered. The abovementioned thermodynamic properties are quantitatively evaluated from the experimental uptake data for methane adsorption onto activated carbons such as Maxsorb III at temperatures ranging from 120 to 350 K and pressures up to 25 bar. Employing the proposed thermodynamic approaches, this paper shows the thermodynamic maps of the charge and discharge processes of adsorbed natural gas (ANG) storage system for understanding the behaviors of natural gas in ANG vessel. © 2011 Elsevier Ltd. All rights reserved.

  12. Review of solid adsorption solar refrigeration II: An overview of the principles and theory

    International Nuclear Information System (INIS)

    A review of the basic principles and theories of solid adsorption solar refrigeration is presented. The cycle performance thermodynamics is also reviewed, and the criteria for selection of adsorbent/adsorbent pairs are reported. The practically realised solar adsorption cooling systems were categorized by their adsorbate operating pressure ranges as low and high pressure systems, and their pertinent design features are given. Adsorption equilibrium models that account for the adsorption properties of a pair of adsorbent/adsorbate and act as state equations in analytical models of the machine are reported

  13. Hydrogen adsorption in doped porous carbons

    International Nuclear Information System (INIS)

    Full text of publication follows: Hydrogen is a clean fuel that will be used in automotive transport when the problem of storage will be solved. The difficulties of H2 storage (available space, security and performance, etc...) require a material that can store 5 weight % of hydrogen. Research is focused on new materials that can assume the constraints imposed by the automotive applications. Among these materials, the nano-structured carbons (nano-fibers and single walled carbon nano-tubes) were claimed to be promising by numerous authors [1-3]. The more promising carbon materials for hydrogen adsorption are those having micropores (i. e. single walled carbon nano-tubes and activated carbon), for which the energy of sorption of hydrogen molecules is theoretically higher [7- 8]. Presently, the best performance of hydrogen adsorption was found in super-activated micro-porous carbons sorbing 5 weight % at 77 K, and almost 0.5 % at room temperature and 6 MPa [9]. Up to now, the performance of these materials can still be improved as the known mechanism of sorption in these carbon materials: physisorption controlled by Van der Waals attractive forces through London interaction is efficient at cryogenic temperatures (77 K) where the interaction between adsorbent and adsorbate becomes stronger. One way to improve the attractive interaction between adsorbent and molecule is to increase the forces due to the interaction of electrical field and induced dipole of the molecule. This can be theoretically tailored in carbon materials through the electron charge transfer by electron donors who can provide an increase in the electrical field al the surface of the adsorbent. Then, the doping of carbon substrates, appearing to be a promising method to increase the energy of adsorption has been proposed in recent papers as a solution to obtain good hydrogen adsorption properties at appropriate temperatures close to room temperatures [10-12]. Thus, we have studied the adsorption

  14. Hydrogen adsorption in doped porous carbons

    International Nuclear Information System (INIS)

    Full text of publication follows: Hydrogen is a clean fuel that will be used in automotive transport when the problem of storage will be solved. The difficulties of H2 storage (available space, security and performance, etc...) require a material that can store 5 weight % of hydrogen. Research is focused on new materials that can assume the constraints imposed by the automotive applications. Among these materials, the nano-structured carbons (nano-fibers and single walled carbon nano-tubes) were claimed to be promising by numerous authors [1-3]. The more promising carbon materials for hydrogen adsorption are those having micropores (i. e. single walled carbon nano-tubes and activated carbon), for which the energy of sorption of hydrogen molecules is theoretically higher [7-8]. Presently, the best performance of hydrogen adsorption was found in super-activated microporous carbons sorbing 5 weight % at 77 K, and almost 0.5 % at room temperature and 6 MPa [9]. Up to now, the performance of these materials can still be improved as the known mechanism of sorption in these carbon materials: physi-sorption controlled by Van der Waals attractive forces through London interaction is efficient at cryogenic temperatures (77 K) where the interaction between adsorbent and adsorbate becomes stronger. One way to improve the attractive interaction between adsorbent and molecule is to increase the forces due to the interaction of electrical field and induced dipole of the molecule. This can be theoretically tailored in carbon materials through the electron charge transfer by electron donors who can provide an increase in the electrical field at the surface of the adsorbent. Then, the doping of carbon substrates, appearing to be a promising method to increase the energy of adsorption has been proposed in recent papers as a solution to obtain good hydrogen adsorption properties at appropriate temperatures close to room temperatures [10-12]. Thus, we have studied the adsorption

  15. 载镧活性炭对水中氟离子的吸附性能研究%Study on Adsorptive Properties to Fluoride Ion of Lanthanum-loaded Activated Carbon

    Institute of Scientific and Technical Information of China (English)

    胡之阳; 唐思远; 王静; 赵亮

    2011-01-01

    Lanthanum(Ⅲ)-loaded activated carbon is prepared in the current study through acid modification followed by lanthanum impregnation.The adsorption behavior of the material to fluoride ion in water are studied through static adsorption experiment.The result shows,the solution pH values had a major impact on fluoride adsorption with optimal removal(above 96%) observed in acidic solutions,the adsorption isotherm could be well fitted by the Langmuir equation,and the estimated maximum uptake capacity is 21.4 mg/g.%通过酸改性和负载镧改性,制备出一种载镧活性炭吸附材料。采用静态吸附试验研究了该材料对水中氟离子的吸附行为。研究结果表明,该载镧活性炭吸附材料对氟离子的去除率可达到96%以上,较低的pH值有利于吸附,吸附行为符合Langmuir型吸附等温式,最大吸附容量为21.4 mg/g。

  16. Adsorption Behavior and Mechanisms of Surfactants by Farmland Soils in Northeast China

    Institute of Scientific and Technical Information of China (English)

    2011-01-01

    The adsorption of two nonionic surfactants polyethylene glycol tert-octylphenyl ether Triton X-100 (TX-100), polyoxyethylene lauryl ether(Brij35) and an anionic surfactant sodium dodecyl benzene sulfonate(SDBS) by two soils(S1, S2) of different natures and their respective organic-matter-extracted samples(S3, S4) were investigated. These adsorption isotherms show different adsorption stages of different types of surfactants by soils. The data fitted Langmuir equation very well. The adsorption maximum capacity(Q0) indicates that TX-100 and SDBS were in the sequence of S3〉S4〉S1〉S2 in adsorption, however, Brij35 was in the sequence of S4〉S3〉S1〉S2 in adsorption. And the adsorption amounts of the different surfactants by soils followed the order of TX-100〉Brij35〉SDBS. Meanwhile, the adsorption of the nonionic surfactants TX-100 and Brij35 decreased with the increase of their ethylene oxide(EO) numbers. The results indicate that both soil organic matter and mineral played important roles in the adsorption of surfactants, and the adsorption of the surfactants by soils was affected by the physicochemical properties and structures of the soils and surfactants, especially the mineral type and content of soil.

  17. Adsorption of tetracycline from aqueous solutions onto multi-walled carbon nanotubes with different oxygen contents

    Science.gov (United States)

    Yu, Fei; Ma, Jie; Han, Sheng

    2014-06-01

    Oxidized multi-walled carbon nanotubes (MWCNTs) with different oxygen contents were investigated for the adsorption of tetracycline (TC) from aqueous solutions. As the surface oxygen content of the MWCNTs increased, the maximum adsorption capacity and adsorption coefficient of TC increased to the largest values and then decreased. The relation can be attributed to the interplay between the nanotubes' dispersibility and the water cluster formation upon TC adsorption. The overall adsorption kinetics of TC onto CNTs-3.2%O might be dependent on both intra-particle diffusion and boundary layer diffusion. The maximum adsorption capacity of TC on CNTs-3.2%O was achieved in the pH range of 3.3-8.0 due to formation of water clusters or H-bonds. Furthermore, the presence of Cu2+ could significantly enhanced TC adsorption at pH of 5.0. However, the solution ionic strength did not exhibit remarkable effect on TC adsorption. In addition, when pH is beyond the range (3.3-8.0), the electrostatic interactions caused the decrease of TC adsorption capacity. Our results indicate that surface properties and aqueous solution chemistry play important roles in TC adsorption on MWCNTs.

  18. Adsorption of volatile organic compounds in porous metal-organic frameworks functionalized by polyoxometalates

    International Nuclear Information System (INIS)

    The functionalization of porous metal-organic frameworks (Cu3(BTC)2) was achieved by incorporating Keggin-type polyoxometalates (POMs), and further optimized via alkali metal ion-exchange. In addition to thermal gravimetric analysis, IR, single-crystal X-ray diffraction, and powder X-ray diffraction, the adsorption properties were characterized by N2 and volatile organic compounds (VOCs) adsorption measurements, including short-chain alcohols (C<4), cyclohexane, benzene, and toluene. The adsorption enthalpies estimated by the modified Clausius-Clapeyron equation provided insight into the impact of POMs and alkali metal cations on the adsorption of VOCs. The introduction of POMs not only improved the stability, but also brought the increase of adsorption capacity by strengthening the interaction with gas molecules. Furthermore, the exchanged alkali metal cations acted as active sites to interact with adsorbates and enhanced the adsorption of VOCs. - Graphical Abstract: The adsorption behavior of volatile organic compounds in porous metal-organic frameworks functionalized by polyoxometalates has been systematically evaluated. Highlights: → Functionalization of MOFs was achieved by incorporating Keggin-type POMs. → Introduction of POMs improved the thermal stability and adsorption capacity. → Alkali metal ion-exchange modified the inclusion state and also enhanced the adsorption. → Adsorption enthalpies were estimated to study the impact of POMs and alkali metal cations.

  19. Adsorption Characteristics of Pb(2+) onto Wine Lees-Derived Biochar.

    Science.gov (United States)

    Zhu, Qihong; Wu, Jun; Wang, Lilin; Yang, Gang; Zhang, Xiaohong

    2016-08-01

    Biochar has great advantages in soil amendment and polluted soil remediation. Herein, the pore and adsorption properties of wine lees-derived biochar were explored. Specifically, the adsorption isotherm and kinetics of Pb(2+) onto wine lees-derived biochar were examined. Experimental results revealed that wine lees-derived biochar featured large specific surface area and total pore volume, and high contents of -COOH and -OH on its surface. Adsorption of Pb(2+) onto wine lees-derived biochar proceeded via a multilayer adsorption mechanism, as described by the Freundlich adsorption model. Adsorption kinetics followed the Lagergren pseudo-second-order kinetics model; adsorption equilibrium was achieved within 30-60 min. Furthermore, the effect of solution pH on the adsorption of Pb(2+) was investigated. Within the studied pH range of 3-6, the adsorption capacity increased with increasing pH. Under established optimized conditions, wine lees-derived biochar achieved a Pb(2+) adsorption capacity of 79.12 mg/g. PMID:26920696

  20. Adsorption and quantitative estimation of uranium by calcium alginate beads coated with CdS quantum dots

    International Nuclear Information System (INIS)

    A novel method has been developed for quantitative determination of uranium (VI) in the range of 5 - 70 mg/L from fluorescence quenching property of CdS quantum dots coated on calcium alginate microbeads, which revealed linear Stern Volmer plot. These CdS functionalized microbeads exhibited adsorption phenomenon where the maximum adsorption capacity (Qe) was measured to be 7.58 mg/g. The mechanism of adsorption of U (VI) favoured monolayer adsorption as reflected from Langmuir adsorption isotherm. (author)

  1. Increased adsorption of histidine-tagged proteins onto tissue culture polystyrene

    DEFF Research Database (Denmark)

    Holmberg, Maria; Hansen, Thomas Steen; Lind, Johan Ulrik;

    2012-01-01

    In this study we compare histidine-tagged and native proteins with regards to adsorption properties. We observe significantly increased adsorption of proteins with an incorporated polyhistidine amino acid motif (HIS-tag) onto tissue culture polystyrene (TCPS) compared to similar proteins without...... and ethylenediaminetetraacetic acid (EDTA), as well as adsorption performed at different pH and ionic strength indicates that the high adsorption is caused by electrostatic interaction between negatively charged carboxylate groups on the TCPS surface and positively charged histidine residues in the proteins. Pre......-adsorption of bovine serum albumin (BSA) does not decrease the adsorption of HIS-tagged proteins onto TCPS. Our findings identify a potential problem in using HIS-tagged signalling molecule in assays with cells cultured on TCPS, since the concentration of the molecule in solution might be affected and this could...

  2. Carbon dioxide and nitrogen adsorption on cation-exchanged SSZ-13 zeolites.

    Science.gov (United States)

    Pham, Trong D; Liu, Qingling; Lobo, Raul F

    2013-01-15

    Samples of high-silica SSZ-13, ion exchanged with protons and alkali-metal cations Li(+), Na(+), and K(+), were investigated using adsorption isotherms of CO(2) and N(2). The results show that Li-, Na-SSZ-13 have excellent CO(2) capacity at ambient temperature and pressure; in general, Li-SSZ-13 shows the highest capacity for N(2), CO(2) particularly in the low-pressure region. The effect of cation type and Si/Al ratio (6 and 12) on the adsorption properties was investigated through analysis of adsorption isotherms and heats of adsorption. The separation of CO(2) in a flue gas mixture was evaluated for these adsorbents in the pressure swing adsorption and vacuum pressure adsorption processes. PMID:23249267

  3. 改性细菌纤维素硫酸酯对Pb(Ⅱ)吸附性能的影响%Influnce on adsorption property modified bacterial cellulose sulfate to Pb (Ⅱ)

    Institute of Scientific and Technical Information of China (English)

    王吟; 孙凤玲; 杨一琼

    2016-01-01

    Taking bacterial cellulose (BC) as raw material,the paper prepared a modified bacterial cellulose sulphate adsorption material and carried out characterization analysis.It took the removal of Pb (Ⅱ) which is a typical heavy metal pollutant as the target,and investigated the impact of different reaction time,pH value of solution and reaction temperature on the adsorption behavior of Pb (Ⅱ).The results showed that the adsorption capacity of modified bacterial cellulose has been improved.The amount of adsorption on Pb (Ⅱ) by the material increases with the increase of pH and decreases with the increase of temperature.The adsorption process fits two stage reaction equation and Langmuir equation.%以廉价且资源丰富的细菌纤维素为原料,研究制备了改性细菌纤维素硫酸酯吸附材料,并对其进行表征分析.以典型重金属污染物Pb(Ⅱ)为去除目标,考察了不同反应时间、溶液pH和反应温度等对改性细菌纤维素吸附Pb(Ⅱ)的影响.结果表明:经改性后细菌纤维素的吸附性能有所增加;其对Pb(Ⅱ)的平衡吸附量随pH的增大而增加,随温度的增加而减小;吸附过程符合拟二级反应方程和Langmuir吸附等温方程.

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

    International Nuclear Information System (INIS)

    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 pH2O = 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/kgads 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

  5. Adsorption of dyes using different types of clay: a review

    Science.gov (United States)

    Adeyemo, Aderonke Ajibola; Adeoye, Idowu Olatunbosun; Bello, Olugbenga Solomon

    2015-09-01

    Increasing amount of dyes in the ecosystem particularly in wastewater has propelled the search for more efficient low-cost adsorbents. The effective use of the sorption properties (high surface area and surface chemistry, lack of toxicity and potential for ion exchange) of different clays as adsorbents for the removal of different type of dyes (basic, acidic, reactive) from water and wastewater as potential alternatives to activated carbons has recently received widespread attention because of the environmental-friendly nature of clay materials. Insights into the efficiencies of raw and modified/activated clay adsorbents and ways of improving their efficiencies to obtain better results are discussed. Acid-modified clay resulted in higher rate of dye adsorption and an increased surface area and porosity (49.05 mm2 and 53.4 %). Base-modified clay has lower adsorption capacities, while ZnCl2-modified clay had the least rate of adsorption with a surface area of 44.3 mm2 and porosity of 43.4 %. This review also explores the grey areas of the adsorption properties of the raw clays and the improved performance of activated/modified clay materials with particular reference to the effects of pH, temperature, initial dye concentration and adsorbent dosage on the adsorption capacities of the clays. Various challenges encountered in using clay materials are highlighted and a number of future prospects for the adsorbents are proposed.

  6. Molecular adsorption on graphene

    Science.gov (United States)

    Kong, Lingmei; Enders, Axel; Rahman, Talat S.; Dowben, Peter A.

    2014-11-01

    Current studies addressing the engineering of charge carrier concentration and the electronic band gap in epitaxial graphene using molecular adsorbates are reviewed. The focus here is on interactions between the graphene surface and the adsorbed molecules, including small gas molecules (H2O, H2, O2, CO, NO2, NO, and NH3), aromatic, and non-aromatic molecules (F4-TCNQ, PTCDA, TPA, Na-NH2, An-CH3, An-Br, Poly (ethylene imine) (PEI), and diazonium salts), and various biomolecules such as peptides, DNA fragments, and other derivatives. This is followed by a discussion on graphene-based gas sensor concepts. In reviewing the studies of the effects of molecular adsorption on graphene, it is evident that the strong manipulation of graphene’s electronic structure, including p- and n-doping, is not only possible with molecular adsorbates, but that this approach appears to be superior compared to these exploiting edge effects, local defects, or strain. However, graphene-based gas sensors, albeit feasible because huge adsorbate-induced variations in the relative conductivity are possible, generally suffer from the lack of chemical selectivity.

  7. Protein Adsorption in Three Dimensions

    OpenAIRE

    Vogler, Erwin A.

    2011-01-01

    Recent experimental and theoretical work clarifying the physical chemistry of blood-protein adsorption from aqueous-buffer solution to various kinds of surfaces is reviewed and interpreted within the context of biomaterial applications, especially toward development of cardiovascular biomaterials. The importance of this subject in biomaterials surface science is emphasized by reducing the “protein-adsorption problem” to three core questions that require quantitative answer. An overview of the...

  8. Amphiphile Adsorption on Rigid Polyelectrolytes

    OpenAIRE

    Kuhn, Paulo S.; Levin, Yan; Barbosa, Marcia C.; Ravazzolo, Ana Paula

    2007-01-01

    A theory is presented which quantitatively accounts for the cooperative adsorption of cationic surfactants to anionic polyelectrolytes. For high salt concentration we find that the critical adsorption concentration (CAC) is a bilinear function of the polyion monomer and salt concentrations, with the coefficients dependent only on the type of surfactant used. The results presented in the paper might be useful for designing more efficient gene delivery systems.

  9. Weak adsorption and prewetting transitions

    International Nuclear Information System (INIS)

    We review the theory of prewetting and wetting transitions in relation to recent studies of noble gas and H2 adsorption on alkali metal surfaces. An essential feature is that the adsorption potential have extremely small well depths. Open theoretical issues include the accuracy of the potentials, the approximations used in the statistical mechanics, and dynamic effects of the substrate. New adsorbates and substrates are discussed. (orig.)

  10. Effect of effluent organic matter on the adsorption of perfluorinated compounds onto activated carbon

    Energy Technology Data Exchange (ETDEWEB)

    Yu, Jing [State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing 210046 (China); College of Environmental Science and Engineering, Yangzhou University, 196 West Huayang Road, Yangzhou 225127 (China); Lv, Lu, E-mail: esellu@nju.edu.cn [State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing 210046 (China); Lan, Pei [State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing 210046 (China); College of Environmental Science and Engineering, Yangzhou University, 196 West Huayang Road, Yangzhou 225127 (China); Zhang, Shujuan [State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing 210046 (China); Pan, Bingcai, E-mail: bcpan@nju.edu.cn [State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing 210046 (China); Zhang, Weiming [State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing 210046 (China)

    2012-07-30

    Highlights: Black-Right-Pointing-Pointer The presence of EfOM significantly reduced the adsorption capacities and rates of PFCs. Black-Right-Pointing-Pointer Low-molecular-weight EfOM compounds (<1 kDa) compete for adsorption sites of PFSs directly. Black-Right-Pointing-Pointer Large-molecular-weight EfOM compounds (>30 kDa) affect the adsorption through pore blockage or restriction effect. Black-Right-Pointing-Pointer Changes in surface properties of PAC caused by preloaded EfOM could affect PFCs adsorption. - Abstract: Effect of effluent organic matter (EfOM) on the adsorption of perfluorooctane sulfonate (PFOS) and perfluorooctanoate (PFOA) onto powdered activated carbon (PAC) was quantitatively investigated at environmentally relevant concentration levels. The adsorption of both perfluorinated compounds (PFCs) onto PAC followed pseudo-second order kinetics and fitted the Freundlich model well under the given conditions. Intraparticle diffusion was found to be the rate-controlling step in the PFC adsorption process onto PAC in the absence and presence of EfOM. The presence of EfOM, either in PFC-EfOM simultaneous adsorption onto fresh PAC or in PFC adsorption onto EfOM-preloaded PAC, significantly reduced the adsorption capacities and sorption rates of PFCs. The pH of zero point of charge was found to be 7.5 for fresh PAC and 4.2 for EfOM-preloaded PAC, suggesting that the adsorbed EfOM imparted a negative charge on PAC surface. The effect of molecular weight distribution of EfOM on the adsorption of PFCs was investigated with two EfOM fractions obtained by ultrafiltration. The low-molecular-weight compounds (<1 kDa) were found to be the major contributors to the significant reduction in PFC adsorption capacity, while large-molecular-weight compounds (>30 kDa) had much less effect on PFC adsorption capacity.

  11. Adsorption of Phosphate on Goethite: An Undergraduate Research Laboratory Project

    Science.gov (United States)

    Tribe, Lorena; Barja, Beatriz C.

    2004-01-01

    A laboratory experiment on the adsorption of phosphate on goethite is presented, which also includes discussion on surface properties, interfaces, acid-base equilibrium, molecular structure and solid state chemistry. It was seen that many students were able to produce qualitatively correct results for a complex system of real interest and they…

  12. Molecular simulation of fibronectin adsorption onto polyurethane surfaces

    Science.gov (United States)

    Polyethylene glycol-based polyurethanes have been widely used in biomedical applications, however are prone to swelling. A natural polyol, castor oil can be incorporated into these polyurethanes to control the degree of the swelling, which alters mechanical properties and protein adsorption characte...

  13. TIRF and its application to protein adsorption. Electrostatics and orientation.

    NARCIS (Netherlands)

    Bos, M.A.

    1994-01-01

    The aim of the study in this thesis was to develop a method for determining the orientation of adsorbed protein molecules and to study the influence of the electrical potential of the interface on the interfacial properties of proteins, including their orientation.In the adsorption of proteins on so

  14. Adsorption Properties of Amino Acids on Ca/SBA-15 Prepared by Calcium Modification under Microwave Radiation%氨基酸在微波辅助钙改性SBA-15上的吸附性能

    Institute of Scientific and Technical Information of China (English)

    张三山; 张德喜; 肖建国; 刘亚纯; 伏再辉

    2012-01-01

    The calcium modified SBA-15 materials, denoted as Ca / SBA-15 ( MW ) , were prepared by solid-phase method under microwave radiation. The structure of the materials was characterized by small angle XRD, N2 adsorption-desorption, and TEM. Adsorption performance of four typical amino acids on Ca/SBA-15( MW) was studied. Effects of the. calcium loading and pH of amino acid solution on the adsorption performance were investigated. The results show that the calcium modified materials prepared by this method still retain similar structural characteristics of SBA-15, and calcium species are uniformly dispersed in the mesoporous material pore channel. Ca/ SBA-15 (MW) displays better adsorption ability to the adsorption of acidic glutamic acid at pH = 2.0 - 10 as compared to pure silicon SBA-15. Moreover, their adsorption capacity is proportional to calcium content of the samples. For the adsorption of basic amino acid lysine( Lys) , Ca/SBA-15 ( MW) shows the weaker adsorption ability at pH < 10 compared with SBA-15, whereas its adsoiption ability is stronger than that of SBA-15 when the pH value of adsorption solution was adjusted to 10. For the adsorption of some neutral amino acids such as phenylalanine and alanine on SBA-15, their adsorption amount was low at pH =2. 0 ~6. 0 and pH =6. 0 ~ 10. When pH value was ca. 6.0, the maximum adsorption amount of phenylalanine and alanine over SBA-15 was up to 0. 34 and 0. 17 mmol/g, respectively. Ca/SBA-15 ( MW) exhibits a weak adsorption capacity to alanine, and hardly adsorbed phenylalanine. This is likely due to the surface hydrophilicity of the calcium-containing samples, which can lead to a poor adsorption interaction with hydrophobic alanine and especially phenylalanine.%采用微波辐射固相法制备了钙改性SBA-15材料Ca/SBA-15 (MW),借助小角XRD、N2吸附-脱附实验及TEM表征了Ca/SBA-15 (MW)的结构,研究了4种典型的氨基酸在Ca/SBA- 15 (MW)上的吸附性能,并考察了钙负载量和pH值对其

  15. Thiol-functionalized polysilsesquioxane as efficient adsorbent for adsorption of Hg(II) and Mn(II) from aqueous solution

    Energy Technology Data Exchange (ETDEWEB)

    Niu, Yuzhong, E-mail: niuyuzhong@126.com; Qu, Rongjun; Liu, Xiguang; Mu, Lei; Bu, Baihui; Sun, Yuting; Chen, Hou; Meng, Yangfeng; Meng, Lina; Cheng, Lin

    2014-04-01

    Highlights: • PMPSQ was promising adsorbent for the removal of Hg(II) and Mn(II). • The adsorption kinetics followed the pseudo-second-order model. • The adsorption isotherms can be described by the monolayer Langmuir model. • The adsorption was controlled by film diffusion and chemical ion-exchange mechanism. - Abstract: Thiol-functionalized polysilsesquioxane was synthesized and used for the adsorption of Hg(II) and Mn(II) from aqueous solution. Results showed that the optimal pH was about 6 and 5 for Hg(II) and Mn(II), respectively. Adsorption kinetics showed that the adsorption equilibriums were established within 100 min and followed pseudo-second-order model. Adsorption isotherms revealed that the adsorption capacities increased with the increasing of temperature. The adsorption was found to be well described by the monolayer Langmuir isotherm model and took place by chemical ion-exchange mechanism. The thermodynamic properties indicated the adsorption processes were spontaneous and endothermic nature. Selectively adsorption showed that PMPSQ can selectively adsorb Hg(II) from binary ion systems in the presence of the coexistent ions Mn(II), Cu(II), Pb(II), Co(II), and Ni(II). Based on the results, it is concluded that PMPSQ had comparable high adsorption efficiency and could be potentially used for the removal of Hg(II) and Mn(II) from aqueous solution.

  16. ADSORPTION OF POLYCHLORINATED BIPHENYLS BY SOILS

    OpenAIRE

    Mihaela Preda; Radu Lăcătuşu; Dumitru Marian Motelică; Nicoleta Vrînceanu; Veronica Tănase

    2010-01-01

    The behavior of polychlorinated biphenyls (PCBs) in soil is determined by several factors including adsorption, mobility and degradation. Adsorption, directly or indirectly, influences the other factors. Adsorption process is generally evaluated by using adsorption isotherms representing the relationship between the quantity of substance adsorbed per unit weight and concentration of the substance in solution at equilibrium. They allow determination of the adsorption constant, which is directl...

  17. Adsorption refrigeration technology theory and application

    CERN Document Server

    Wang, Ruzhu; Wu, Jingyi

    2014-01-01

    Gives readers a detailed understanding of adsorption refrigeration technology, with a focus on practical applications and environmental concerns Systematically covering the technology of adsorption refrigeration, this book provides readers with a technical understanding of the topic as well as detailed information on the state-of-the-art from leading researchers in the field. Introducing readers to background on the development of adsorption refrigeration, the authors also cover the development of adsorbents, various thermodynamic theories, the design of adsorption systems and adsorption refri

  18. Adsorption of ofloxacin and norfloxacin on carbon nanotubes: Hydrophobicity- and structure-controlled process

    Energy Technology Data Exchange (ETDEWEB)

    Peng, Hongbo [Faculty of Environmental Science and Engineering, Kunming University of Science and Technology, Kunming, Yunnan 650093 (China); Pan, Bo, E-mail: panbocai@gmail.com [Faculty of Environmental Science and Engineering, Kunming University of Science and Technology, Kunming, Yunnan 650093 (China); Wu, Min; Liu, Ying; Zhang, Di [Faculty of Environmental Science and Engineering, Kunming University of Science and Technology, Kunming, Yunnan 650093 (China); Xing, Baoshan [Department of Plant, Soil and Insect Sciences, University of Massachusetts, Amherst, MA 01003 (United States)

    2012-09-30

    Highlights: Black-Right-Pointing-Pointer A significant relationship between K{sub d} and SSA for both OFL and NOR on CNTs. Black-Right-Pointing-Pointer No relationship was observed between K{sub d}s and oxygen content of CNTs. Black-Right-Pointing-Pointer Normalizing K{sub d}s by solubilites enlarged OFL and NOR sorption difference. Black-Right-Pointing-Pointer OFL and NOR sorption was controlled by their structural- and hydrophobic-properties. - Abstract: Adsorption of antibiotics on solid particles is a key process controlling their fate in the subsurface. This study compared the adsorption of ofloxacin and norfloxacin (NOR) on carbon nanotubes (CNTs) to evaluate the role of structural and hydrophobic properties in regulating their adsorption. A significant relationship was observed between single-point adsorption coefficients (K{sub d}) and specific surface area (highly hydrophobic), but not between K{sub d}s and oxygen content. This result suggested that site-specific adsorption was not important but hydrophobic effect may have an important contribution to OFL and NOR adsorption on CNTs. However, normalizing the adsorption coefficients by OFL and NOR solubilities enlarged their adsorption difference indicating that hydrophobicity was not the only factor controlling the difference between OFL and NOR adsorption on CNTs. Their chemical structures show that both chemicals could interact with CNTs through an electron-donor-acceptor mechanism. This mechanism was correlated with the different adsorption of OFL and NOR on functionalized CNTs (namely hydroxylized, carboxylized, and graphitized CNTs). This study revealed that OFL and NOR adsorption was controlled by their both structural- and hydrophobic-properties.

  19. Adsorptive removal of heavy metals by magnetic nanoadsorbent: an equilibrium and thermodynamic study

    Science.gov (United States)

    Shirsath, D. S.; Shirivastava, V. S.

    2015-11-01

    An efficient and new magnetic nanoadsorbent photocatalyst was fabricated by co-precipitation technique. This research focuses on understanding metal removal process and developing a cost-effective technology for treatment of heavy metal-contaminated industrial wastewater. In this investigation, magnetic nanoadsorbent has been employed for the removal of Zn(II) ions from aqueous solutions by a batch adsorption technique. The adsorption equilibrium data fitted very well to Langmuir and Freundlich adsorption isotherm models. The thermodynamics of Zn(II) ions adsorption onto the magnetic nanoadsorbents indicated that the adsorption was spontaneous, endothermic and physical in nature. Surface morphology of magnetic nanoadsorbent by scanning electron microscopy (SEM) and elemental analysis by EDX technique. The structural and photocatalytic properties of magnetic nanoadsorbent were characterized using X-ray diffraction (XRD) and FTIR techniques. Also, the magnetic properties of synthesized magnetic nanoadsorbent were determined by vibrating spinning magnetometer (VSM).

  20. The dynamic adsorption of Xe on a fixed bed adsorber at 77 K

    CERN Document Server

    Long, Bin; Wang, Qun- Shu; Feng, Shu- Juan; Zhou, Guo- Qing; Feng, Tian- Cheng; Tian, Yan- Jie; Ma, Huai- Cheng

    2016-01-01

    During the design of fixed bed adsorbers, it is vital to understand the dynamic adsorption properties of the system. Because temperature is one of the most important factors affecting adsorbent performance, such that the dynamic adsorption coefficients tend to increase as the temperature decreases, the dynamic adsorption characteristics of Xe on a fixed bed adsorber at 77 K were studied in the present work to minimize the volume of fixed bed adsorber, employing a variety of adsorbents under different operational conditions. The results show that the adsorption performance of carbon molecular sieve is superior to that of activated carbon. And both operational conditions and the presence of gaseous impurities were found to affect adsorption properties.

  1. Effect of temperature on the adsorption of short alkanes in the zeolite ssz-13-adapting adsorption isotherms to microporous materials

    NARCIS (Netherlands)

    Jiang, Tao; Göltl, Florian; Bulo, Rosa E.; Sautet, Philippe

    2014-01-01

    Understanding the diffusion and adsorption of hydrocarbons in zeolites is a highly important topic in the field of catalysis in micro-and mesoporous materials. Especially, the properties of alkanes in zeolites have been studied extensively. A theoretical description of these processes is challenging

  2. Trichloroethylene (TCE) adsorption using sustainable organic mulch

    International Nuclear Information System (INIS)

    Soluble substrates (electron donors) have been commonly injected into chlorinated solvent contaminated plume to stimulate reductive dechlorination. Recently, different types of organic mulches with economic advantages and sustainable benefits have received much attention as new supporting materials that can provide long term sources of electron donors for chlorinated solvent bioremediation in engineered biowall systems. However, sorption capacities of organic mulches for chlorinated solvents have not been studied yet. In this study, the physiochemical properties of organic mulches (pine, hardwood and cypress mulches) were measured and their adsorption capacity as a potential media was elucidated. Single, binary and quaternary isotherm tests were conducted with trichloroethylene (TCE), tetrachloroethylene (PCE), trans-dichloroethylene (trans-DCE) and cis-dichloroethylene (cis-DCE). Among the three tested mulches, pine mulch showed the highest sorption capacity for the majority of the tested chemicals in single isotherm test. In binary or quaternary isotherm tests, competition among chemicals appears to diminish the differences in Qe for tested mulches. However, pine mulch also showed higher adsorption capacity for most chemicals when compared to hardwood and cypress mulches in the two isotherm tests. Based upon physicochemical properties of the three mulches, higher sorption capacity of pine mulch over hardwood and cypress mulches appears to be attributed to a higher organic carbon content and the lower polarity.

  3. Preparation of Functionalized Carbonaceous Magnetic Mesoporous Composite and Its Adsorption Property to Uranium%功能化炭基磁性介孔材料的制备及其对铀的吸附性能

    Institute of Scientific and Technical Information of China (English)

    彭国文; 肖方竹; 孙世雄; 张志军; 胡南; 王晓亮; 丁德馨

    2015-01-01

    以介孔氧化硅SBA-15为模板 ,通过纳米浇筑法在模板孔道中引入不同质量的铁源和炭源作为前驱物 ,经过原位聚合反应 ,再使用[3-(三甲氧基硅烷)丙基]脲(UPTS)和氨丙基三乙氧基硅烷(APS)有机试剂对其表面进行后嫁接改性 ,得到介孔结构规整有序的功能化炭基磁性介孔材料(FCMMC).并通过红外光谱(FT-IR)、N2 吸附-脱附分别表征了FCMMC的结构.考察了溶液pH值、铀初始浓度、吸附剂用量和吸附时间等因素对FCMMC吸附铀的影响.结果表明 :炭基和铁基均被负载在介孔氧化硅基体上 ,FCMMC具有较高的比表面积和较窄的孔径分布.FCMMC吸附铀的最佳条件为 :pH=6.0、铀初始浓度25 mg/L、FCMMC用量40 mg、吸附时间1.0 h.对吸附动力学模型和吸附等温模型进行了分析 ,FCMMC对铀的吸附动力学过程符合准二级动力学模型 ,吸附等温线符合Langmuir等温线模型 ,最大理论吸附量为128.69 mg/g.同时 ,使用3种不同的解吸剂对FCMMC解吸再生8次后 ,其对铀的吸附率均在80% 以上 ,说明FCMMC具有良好的再生性能.%The macroporous silica SBA-15 as the hard template ,a novel functionalized carbonaceous magnetic mesoporous composite (FCMMC ) with highly ordered meso-porous structure was obtained using ferric nitrate and glucose as the precursors via one-step nanocasting followed by in-situ polymerization reaction ,and using organic reagents UPTS and APS after grafting modification on its surface .FT-IR and N2 adsorption-stripping experiment were used to characterize FCMMC ,and the factors impacting the adsorption of uranium on FCMMC were investigated including pH value ,initial concen-tration of uranium ions ,FCMMC dosage and adsorption time .The results show that the carbon and iron resource are successfully loaded on the mesoporous silica substrate , respectively .And FCMMC has high specific surface area and narrow pore size distribu-tion .The optimal adsorption

  4. Effects of polyethyleneimine adsorption on rheology of bentonite suspensions

    Indian Academy of Sciences (India)

    A Alemdar; N Öztekin; F B Erim; Ö I Ece; N Güngör

    2005-06-01

    The influence of the cationic polymer, polyethyleneimine polymer (PEI) on the flow behaviour of bentonite suspensions (2%, w/w), was studied. XRD, zeta potential and adsorption studies were done together with rheological measurements. The addition of PEI at concentration ranges of 10-5–4.5 g/l and their rheological properties and stability of bentonite suspensions were studied. The adsorption rates for the bentonite suspensions are very fast. The XRD results showed that the PEG molecules did not intercalate into the layers of the clay.

  5. Extremely high negative electron affinity of diamond via magnesium adsorption

    OpenAIRE

    O'Donnell, Kane M.; Edmonds, Mark T.; Tadich, Anton; Thomsen, Lars; Stacey, Alastair; Schenk, Alex; Pakes, Chris I.; Ley, Lothar

    2015-01-01

    We report large negative electron affinity (NEA) on diamond (100) using magnesium adsorption on a previously oxygen-terminated surface. The measured NEA is up to $(-2.01\\pm0.05)$ eV, the largest reported negative electron affinity to date. Despite the expected close relationship between the surface chemistry of Mg and Li species on oxygen-terminated diamond, we observe differences in the adsorption properties between the two. Most importantly, a high-temperature annealing step is not required...

  6. Adsorption of oxygen on InB5 compounds

    International Nuclear Information System (INIS)

    Results of complex studying oxygen adsorption on real surface of indium group A3B5 type compounds in the 250-670 K temperature range and under 1-150 Pa pressures are presented. Adsorption characteristics and regularities of their variation in InSb, InAs, InP series are determined. Adsorbed oxygen effect on electrophysical and magnetic properties of the above-mentioned compounds is studied. A scheme of mechanism of oxygen interaction with InB5 surface is suggested

  7. Adsorption by powders and porous solids principles, methodology and applications

    CERN Document Server

    Rouquerol, Jean; Llewellyn, Philip; Maurin, Guillaume; Sing, Kenneth SW

    2013-01-01

    The declared objective of this book is to provide an introductory review of the various theoretical and practical aspects of adsorption by powders and porous solids with particular reference to materials of technological importance. The primary aim is to meet the needs of students and non-specialists who are new to surface science or who wish to use the advanced techniques now available for the determination of surface area, pore size and surface characterization. In addition, a critical account is given of recent work on the adsorptive properties of activated carbons, oxides, clays and zeolit

  8. 磁性壳聚糖/β-环糊精复合微球的制备及其吸附性能%Preparation and Adsorption Properties of a Novel Chitosan/β-Cyclodextrin Magnetic Microspheres

    Institute of Scientific and Technical Information of China (English)

    何秋星; 王学文; 陈文婷

    2012-01-01

    以反相悬浮交联法制备磁性壳聚糖/β-环糊精复合微球.用光学显微镜、红外光谱仪、振动样品磁强计(VSM)对微球进行了表征,并研究其对模型蛋白(木瓜蛋白酶)的吸附行为.结果表明,微球为完整的球形,具有良好的磁响应性.模型蛋白在微球上的吸附关系既可用Langmuir方程描述,又可用计量置换吸附Freundlich方程描述,且更符合Freundlich方程描述;聚丙烯酰胺凝胶电泳(SDS-PAGE)结果表明,吸附的模型蛋白能从磁性粒子表面完整地脱附下来.%A series of novel magnetic microspheres were prepared by inverse suspension crosslinking method from chitosan,β-cyclodextrin and Fe3O4. The obtained magnetic microspheres were characterized by means of optical microscope, IR and VSM. The adsorption behaviour of those microspheres towards papain was investigated. The results show that the microspheres were in a spherical shape with good magnetic response. The adsorption behaviour of the microspheres towards papain was described by both the Langmuir adsorption isotherm and the Freundlich isotherm, which shows that the adsorption behaviour fitted more to the Freundlich isotherm. Sodium dodecyl sulfatepolyacrylamide gel electrophoresis (SDS - PAGE) shows that the papain could be desorbed from the magnetic microspheres without denaturation.

  9. A Photochemical Reactor for the Study of Kinetics and Adsorption Phenomena

    Science.gov (United States)

    Poce-Fatou, J. A.; Gil, M. L. A.; Alcantara, R.; Botella, C.; Martin, J.

    2004-01-01

    The interaction between light and matter is examined with the help of a photochemical experiment. This experiment is useful for the investigation of heterogeneous catalysis, semiconductor properties and adsorption phenomena.

  10. Analytical and numerical study of particles with binary adsorption

    OpenAIRE

    Dias, Cristóvão S.; Araújo, Nuno A. M.; Cadilhe, António

    2012-01-01

    Electro-oxidation of ethanol represents a key process in fuel-cells technology. We introduce a generalization of the random sequential adsorption model to study the long timescale and large length scale properties of the electro-oxidation process. We provide an analytical solution for one dimension and Monte Carlo results in two dimensions. We characterize the coverage and percolation properties of the jammed state and unveil the influence of quenched impurities in the selectivity of oxidatio...

  11. Thermostimulated exoemission and adsorption centres of BeO-ceramics

    International Nuclear Information System (INIS)

    Dehydration and adsorption effects on the parameters of thermally stimulated exoemission (TSE) from ceramic samples of BeO are investigated. Adsorption of active gases increase the emissivity of BeO if it is dehydrated by thermovacuum treatment. For the original hydrated sample the adsorption results in a small decrease of TSE intensity. For recombination proceeding in the mobile surface layer it is necessary that it should have some optimum concentration of adsorbed particles. It is an explanation for the data obtained. The results of the experiments lead to the conclusion that the discrepancies between the existing data on exoemission properties of BeO are caused by the difference in pretreatment technique and readout conditions accepted by different experimenters. (author)

  12. Hydrogen adsorption on nitrogen and boron doped graphene

    International Nuclear Information System (INIS)

    Hydrogen adsorption on boron and nitrogen doped graphene is investigated in detail by means of first-principles calculations. A comprehensive study is performed of the structural, electronic, and magnetic properties of chemisorbed hydrogen atoms and atom pairs near the dopant sites. The main effect of the substitutional atoms is charge doping which is found to greatly affect the adsorption process by increasing the binding energy at the sites closest to the substitutional species. It is also found that doping does not induce magnetism despite the odd number of electrons per atom introduced by the foreign species, and that it quenches the paramagnetic response of chemisorbed H atoms on graphene. Overall, the effects are similar for B and N doping, with only minor differences in the adsorption energetics due to different sizes of the dopant atoms and the accompanying lattice distortions. (paper)

  13. Adsorption of radon from a humid atmosphere on activated carbon

    International Nuclear Information System (INIS)

    Temperature and relative humidity can influence the adsorption capacity of radon on activated carbon to a great extent, depending on the physical properties of the carbon. Experiments were carried out to measure the radon uptake by an activated carbon in the presence of water vapor in a specially designed adsorption apparatus. The radon concentrations in the gas and solid phases were measured simultaneously once the adsorption equilibrium and the radioactive equilibrium between the radon daughter products were reached. The experiments in the presence of water vapor were carried out using two approaches. In one case the activated carbon was preequilibrated with water vapor prior to exposing it to radon. In the other case the carbon was exposed to a mixture of water vapor and radon. The uptake capacity for radon decreased substantially when both components were introduced together compared to when carbon was preequilibrated with water

  14. Study of sulfur dioxide adsorption on Y zeolite

    Directory of Open Access Journals (Sweden)

    IOAN SANDULESCU

    2004-07-01

    Full Text Available Sulfur dioxide adsorptive properties of Y zeolite, the structure of which was confirmed by XRD, were investigated at temperatures within the 25–200 ºC range and sulfur dioxide concentrations between 0.9 to 6 % (vol./vol.. It was found that this sorbent possesses a relatively high adsorption capacity. The Y zeolite did not lose its activity during 20 adsorption-desorption-regeneration cycles. The manner in which sulfur dioxide is adsorbed on Y type zeolite was also investigated by analyzing the sample with and without adsorbed SO2, using IR spectroscopy, as well as total and Lewis acidity measurements. The sulfur dioxide molecule is probably adsorbed by hydrogen bonding to one or two conveniently positioned surface hydroxyl groups.

  15. Adsorption of ionizable organic contaminants on multi-walled carbon nanotubes with different oxygen contents

    Energy Technology Data Exchange (ETDEWEB)

    Li Xiaona; Zhao Huimin [Key Laboratory of Industrial Ecology and Environmental Engineering (MOE), School of Environmental Science and Technology, Dalian University of Technology, Linggong Road 2, Liaoning Province, Dalian 116024 (China); Quan Xie, E-mail: quanxie@dlut.edu.cn [Key Laboratory of Industrial Ecology and Environmental Engineering (MOE), School of Environmental Science and Technology, Dalian University of Technology, Linggong Road 2, Liaoning Province, Dalian 116024 (China); Chen Shuo; Zhang Yaobin; Yu Hongtao [Key Laboratory of Industrial Ecology and Environmental Engineering (MOE), School of Environmental Science and Technology, Dalian University of Technology, Linggong Road 2, Liaoning Province, Dalian 116024 (China)

    2011-02-15

    Multi-walled carbon nanotubes (MWNTs), which are considered to be promising candidates for the adsorption of toxic organics, are released into aqueous environment with their increasing production and application. In this study, the adsorption behaviors of five structurally related ionizable organic contaminants namely perfluorooctane sulfonate (PFOS), perfluorooctanoic acid (PFOA), perfluorooctanesulfonamide (PFOSA), 2,4-dichlorophenoxyacetic acid (2,4-D) and 4-n-nonylphenol (4-NP) onto MWNTs with different oxygen contents (3.84-22.85%) were investigated. The adsorption kinetics was investigated and simulated with pseudo-second-order model. The adsorption isotherms were found to be fitted with Freundlich model and influenced by both the properties of organic chemicals and the oxygen contents of MWNTs. As adsorption capacity decreases dramatically with the increasing of oxygen contents, the MWNTs with the lowest oxygen contents possess the highest adsorption capacity among four MWNTs. For the MWNTs with the oxygen contents of 3.84%, the adsorption affinity related with hydrophobic interaction and {pi}-electron polarizability decreased in the order of 4-NP > PFOSA > PFOS > 2,4-D > PFOA. Furthermore, the adsorption characters of five contaminants were affected by solution pH and solute pK{sub a} considering electrostatic repulse force and hydrogen bonding, which showed the adsorption of MWNTs with lower oxygen content is much sensitive to solution chemistry.

  16. Adsorption of ionizable organic contaminants on multi-walled carbon nanotubes with different oxygen contents

    International Nuclear Information System (INIS)

    Multi-walled carbon nanotubes (MWNTs), which are considered to be promising candidates for the adsorption of toxic organics, are released into aqueous environment with their increasing production and application. In this study, the adsorption behaviors of five structurally related ionizable organic contaminants namely perfluorooctane sulfonate (PFOS), perfluorooctanoic acid (PFOA), perfluorooctanesulfonamide (PFOSA), 2,4-dichlorophenoxyacetic acid (2,4-D) and 4-n-nonylphenol (4-NP) onto MWNTs with different oxygen contents (3.84-22.85%) were investigated. The adsorption kinetics was investigated and simulated with pseudo-second-order model. The adsorption isotherms were found to be fitted with Freundlich model and influenced by both the properties of organic chemicals and the oxygen contents of MWNTs. As adsorption capacity decreases dramatically with the increasing of oxygen contents, the MWNTs with the lowest oxygen contents possess the highest adsorption capacity among four MWNTs. For the MWNTs with the oxygen contents of 3.84%, the adsorption affinity related with hydrophobic interaction and π-electron polarizability decreased in the order of 4-NP > PFOSA > PFOS > 2,4-D > PFOA. Furthermore, the adsorption characters of five contaminants were affected by solution pH and solute pKa considering electrostatic repulse force and hydrogen bonding, which showed the adsorption of MWNTs with lower oxygen content is much sensitive to solution chemistry.

  17. Resolution of Adsorption and Partition Components of Organic Compounds on Black Carbons.

    Science.gov (United States)

    Chiou, Cary T; Cheng, Jianzhong; Hung, Wei-Nung; Chen, Baoliang; Lin, Tsair-Fuh

    2015-08-01

    Black carbons (BCs) may sequester non-ionic organic compounds by adsorption and/or partition to varying extents. Up to now, no experimental method has been developed to accurately resolve the combined adsorption and partition capacity of a compound on a BC. In this study, a unique "adsorptive displacement method" is introduced to reliably resolve the adsorption and partition components for a solute-BC system. It estimates the solute adsorption on a BC by the use of an adsorptive displacer to displace the adsorbed target solute into the solution phase. The method is validated by tests with uses of activated carbon as the model carbonaceous adsorbent, soil organic matter as the model carbonaceous partition phase, o-xylene and 1,2,3-trichlorobenzene as the reference solutes, and p-nitrophenol as the adsorptive displacer. Thereafter, the adsorption-partition resolution was completed for the two solutes on selected model BCs: four biochars and two National Institute of Standards and Technology (NIST) standard soots (SRM-2975 and SRM-1650b). The adsorption and partition components resolved for selected solutes with given BCs and their dependences upon solute properties enable one to cross-check the sorption data of other solutes on the same BCs. The resolved components also provide a theoretical basis for exploring the potential modes and extents of different solute uptakes by given BCs in natural systems. PMID:26114972

  18. Eriobotrya japonica seed biocomposite efficiency for copper adsorption: Isotherms, kinetics, thermodynamic and desorption studies.

    Science.gov (United States)

    Mushtaq, Mehwish; Bhatti, Haq Nawaz; Iqbal, Munawar; Noreen, Saima

    2016-07-01

    Adsorption techniques are widely used to remove pollutants from wastewater; however, composites are gaining more importance due to their excellent adsorption properties. Bentonite composite with Eriobotrya japonica seed was prepared and used for the adsorption of copper (Cu) metal from aqueous media. The process variables such as pH, Cu(II) ions initial concentration, adsorbent dose, contact time and temperature were optimized for maximum Cu(II) adsorption. At pH 5, adsorbent dose 0.1 g, contact time 45 min, Cu(II) ions initial concentration 75 mg/L and temperature 45 °C, maximum Cu(II) adsorption was achieved. Desorption studies revealed that biocomposite is recyclable. Langmuir, Freundlich and Harkins-Jura isotherms as well as pseudo-first and pseudo-second-order kinetics models were applied to understand the adsorption mechanism. Thermodynamic parameters (ΔG(0), ΔH(0) and ΔS(0)) suggest that the adsorption process was spontaneous and endothermic in nature. The pseudo-second-order kinetic model and Langmuir isotherm fitted well to the adsorption data. Results showed that biocomposite was more efficient for Cu(II) adsorption in comparison to individuals native Eriobotrya japonica seed biomass and Na-bentonite. PMID:27039361

  19. Co-adsorption of Trichloroethylene and Arsenate by Iron-Impregnated Granular Activated Carbon.

    Science.gov (United States)

    Deng, Baolin; Kim, Eun-Sik

    2016-05-01

    Co-adsorption of trichloroethylene (TCE) and arsenate [As(V)] was investigated using modified granular activated carbons (GAC): untreated, sodium hypochlorite-treated (NaClO-GAC), and NaClO with iron-treated GAC (NaClO/Fe-GAC). Batch experiments of single- [TCE or As(V)] and binary- [TCE and As(V)] components solutions are evaluated through Langmuir and Freundlich isotherm models and adsorption kinetic tests. In the single-component system, the adsorption capacity of As(V) was increased by the NaClO-GAC and the NaClO/Fe-GAC. The untreated GAC showed a low adsorption capacity for As(V). Adsorption of TCE by the NaClO/Fe-GAC was maximized, with an increased Freundlich constant. Removal of TCE in the binary-component system was decreased 15% by the untreated GAC, and NaClO- and NaClO/Fe-GAC showed similar efficiency to the single-component system because of the different chemical status of the GAC surfaces. Results of the adsorption isotherms of As(V) in the binary-component system were similar to adsorption isotherms of the single-component system. The adsorption affinities of single- and binary-component systems corresponded with electron transfer, competitive adsorption, and physicochemical properties. PMID:27131303

  20. A biological oil adsorption filter

    Energy Technology Data Exchange (ETDEWEB)

    Pasila, A. [University of Helsinki (Finland). Dept. of Agricultural Engineering and Household Technology

    2005-12-01

    A new oil adsorption method called adsorption filtration (AF) has been developed. It is a technology where by oil residues can be cleaned from water by running it through a simple filter made from freeze treated, dried, milled and then fragmented plant material. By choosing suitable plants and fragmentation sizes it is possible to produce filters, which pass water but adsorb oil. The aim of this study was to investigate the possibilities of manufacturing oil adsorbing filter materials from reed canary grass (Phalaris arundinacea), flax (Linum usitatissimum L.) or hemp fibre (Cannabis sativa L.). The oil (80 ml) was mixed with de-ionised water (200 ml) and this mixture was filtered through 10 or 20 g adsorption filters. Fine spring harvested hemp fibre (diameter less than 1 mm) and reed canary grass fragments adsorb 2-4 g of oil per gram of adsorption material compared to 1-3 g of water. Adsorption filtration is thus a novel way of gathering spilled oil in shallow coastal waters before the oil reaches the shore. (author)