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Adsorption Properties (adsorption + property)

Distribution by Scientific Domains

Chemistry	60%
Polymers and Materials Science	28%
3 Other Domains	12%

Distribution within Chemistry

General & Introductory Chemistry	33%
Chemical Engineering	20%

Selected Abstracts

Titelbild: Solid Solutions of Soft Porous Coordination Polymers: Fine-Tuning of Gas Adsorption Properties (Angew. Chem.

ANGEWANDTE CHEMIE, Issue 28 2010
28/2010)
Die Eigenschaften poröser Gerüste lassen sich über mesoskalige Domänen in porösen Koordinationspolymeren (PCPs) einstellen. In ihrer Zuschrift auf S.,4930,ff. beschreiben S. Horike, S. Kitagawa et,al. die Synthese von Kristallen, die zweierlei elastische Schichten enthalten. Über die Zusammensetzung dieser festen PCP-Lösungen können das Gassorptionsverhalten variiert und die Fähigkeit zur Trennung eines CO2/CH4 -Gemischs gegenüber den Stammverbindungen verbessert werden. [source]

Solid Solutions of Soft Porous Coordination Polymers: Fine-Tuning of Gas Adsorption Properties

ANGEWANDTE CHEMIE, Issue 28 2010
Tomohiro Fukushima
Die Trennung von CO2und CH4 in einer Mischung wurde optimiert, indem die Zusammensetzung fester Lösungen aus ineinandergreifenden zweidimensionalen Netzen mit zwei unterschiedlichen Isophthalatliganden variiert wurde (siehe Bild). Die Charakteristika der festen Lösungen hingen vom Verhältnis der Liganden ab, das die Elastizität der Netze und dadurch auch deren Adsorptionseigenschaften beeinflusste. [source]

ChemInform Abstract: Theoretical Study on (Al2O3)n (n = 1,10 and 30) Fullerenes and H2 Adsorption Properties.

CHEMINFORM, Issue 24 2008
Jiao Sun
Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a "Full Text" option. The original article is trackable via the "References" option. [source]

Confinement in Nanopores at the Oxide/Water Interface: Modification of Alumina Adsorption Properties

CHEMISTRY - A EUROPEAN JOURNAL, Issue 20 2008
Manuel Baca Dr.
Abstract There is limited knowledge on the influence of the pore size on surface phenomena (adsorption, dissolution, precipitation, etc.) at the oxide/water interface and a better understanding of the space confinement in nanoscale pores should have practical implications in different areas, such as transport of contaminants in the environment or heterogeneous catalyst preparation, to name a few. To investigate the modifications of the oxide adsorption properties at the oxide/water interface in a confined environment, the surface acidobasic and ion adsorption properties of six different aluminas (5 porous commercial aluminas with pore diameters ranging from 25 to 200,Å and 1 non-porous alumina) were determined by means of acid,base titration and Ni(II) adsorption. It is shown that the confinement has a moderate impact on the alumina adsorption capacity because all materials have similar surface charging behaviours and ion saturation coverages. However, a confined geometry has a much larger impact on the ion adsorption constants, which decrease drastically when the average pore diameter decreases below 200,Å. These results are discussed in terms of nanoscale pore space confinement. [source]

A Novel Self-assembled Supramolecular Complex {[Cu(n) (en)2·H2O] [Cu(I)2(CN)4]}n with Honeycomb-like Structure and Its Adsorption Properties

CHINESE JOURNAL OF CHEMISTRY, Issue 12 2002
Xiao-Ping Shen
Abstract A novel supramolecular complex {[Cu(n)(en)2·H2O]·[Cu(I)2(CN)4]}n (en = ethylenediamine), in which the cyanide-bridged Cu(I) forms the honeycomb-like skeleton host and the Cu(n) complex ion [Cu(en)2·H2O]2+ is encapsulated in the center of the channel cavity of the skeleton, was synthesized by two different methods. The complex was also characterized by elemental analysis, ICP analysis, IR spectra and thermal analysis. The adsorption and desorption studies of the complex indicate that H2O and NH3 can be desorbed and re-adsorbed without collapse of the channel structure of the supramolecule. [source]

Structural Characterization and Protein Adsorption Property of Hydroxyapatite Particles Modified With Zinc Ions

JOURNAL OF THE AMERICAN CERAMIC SOCIETY, Issue 2 2007
Satoshi Hayakawa
Zinc-containing hydroxyapatite particles (Zn/HAp) were prepared by an ion exchange reaction process involving hydroxyapatite (HAp) particles with aqueous solutions containing various amounts of zinc nitrate. The Zn2+ ion was partially substituted for the Ca2+ ion position in the HAp lattice, and hence, the obtained samples had changed little in crystallinity, particle size, and specific surface area. Adsorption of bovine serum albumin (BSA) and ,2 -microglobulin (,2 -MG) in solutions containing both BSA and ,2 -MG was examined. As the Zn2+ ion content in the apatites increased, the adsorbed amount of BSA was almost constant, whereas that of ,2 -MG increased. [source]

Adsorption properties of microwave synthesized inorgano,organo montmorillonite

ASIA-PACIFIC JOURNAL OF CHEMICAL ENGINEERING, Issue 2 2010
Miray Emreol
Abstract The aim of this study is to determine the adsorption properties of microwave synthesized inorgano,organo montmorillonites. Microwave irradiation is preferred because of its low time and energy consumption properties, forming an advantage in industrial applications. In addition to the intercalation of Keggin and hexadecyltrimethylammonium (HDTMA+) cations, the aging process of pillaring solution was also carried out through the microwave irradiation. Both inorgano clays, namely the parents, and their inorgano,organo derivatives, were prepared by using the same amounts of aluminum by keeping the OH,/Al3+ and Al3+/clay ratios constant. The HDTMA+/clay ratio was changed in inorgano-organo clays (IOCs) during the preparation. The effects of these parameters on the surface properties and adsorption behaviors of the samples were investigated by conducting X-ray diffraction (XRD), Fourier transform infrared (FTIR) and simultaneous thermal analyses (STA), as well as batch adsorption experiments, in which phenol was used as a model pollutant. The results of XRD analyses reveal that the intercalation is successfully achieved. The existence of the Keggin and HDTMA+ cations was observed in FTIR spectra of the samples. Through the STA, it was determined that the existence of organic layer increases the dehydroxylation temperature and the thermal behavior of inorgano-organo montmorillonites strongly depends on the structure of the parent clay. An increase in the adsorption efficiencies with increasing HDTMA+/clay ratio was observed, except with the highest ratio. The behavior of this sample was explained by the formation of the second HDTMA+ layer leading to the hydrophilic surface formation. Copyright © 2009 Curtin University of Technology and John Wiley & Sons, Ltd. [source]

Synthesis,Structure,Property Relationships for Hyperbranched Aminosilica CO2 Adsorbents

ADVANCED FUNCTIONAL MATERIALS, Issue 23 2009
Jeffrey H. Drese
Abstract Hyperbranched aminosilica (HAS) adsorbents are prepared via the ring-opening polymerization of aziridine in the presence of mesoporous silica SBA-15 support. The aminopolymers are covalently bound to the silica support and capture CO2 reversibly in a temperature swing process. Here, a range of HAS materials are prepared with different organic loadings. The effects of organic loading on the structural properties and CO2 adsorption properties of the resultant hybrid materials are examined. The residual porosity in the HAS adsorbents after organic loading, as well as the molecular weights and degrees of branching for the separated aminopolymers, are determined to draw a relationship between adsorbent structure and performance. Humid adsorption working capacities and apparent adsorption kinetics are determined from experiments in a packed-bed flow system monitored by mass spectrometry. Dry adsorption isotherms are presented for one HAS adsorbent with a high amine loading at 35 and 75,°C. These combined results establish the relationships between adsorbent synthesis, structure, and CO2 adsorption properties of the family of HAS materials. [source]

Synthesis and Characterization of a Composite Zeolite,Metglas Carbon Dioxide Sensor,

ADVANCED FUNCTIONAL MATERIALS, Issue 7 2005
G. Giannakopoulos
Abstract The synthesis of a faujasite,Metglas composite material that can be used in gas-sensing applications is presented. A continuous faujasite film was synthesized on a Metglas magnetoelastic strip using the secondary growth method. The ability of the new composite to remotely sense carbon dioxide in a nitrogen atmosphere at room temperature over a wide range of concentrations is demonstrated by monitoring the changes in the resonance frequency of the strip. The novel sensor combines the electromagnetic properties of the magnetoelastic material with the adsorption properties of the faujasite crystals. Experiments performed over a period of a few months showed that the composite sensor remained fully operational, thus indicating its long-term stability. Furthermore, the present work demonstrates that a zeolite,Metglas composite can be used as a sensor of an analyte in a mixture as long as it adsorbs selectively larger amounts of the particular analyte than other compounds present in the mixture. [source]

Parametric study on the silica gel,calcium chloride composite desiccant rotary wheel employing fractal BET adsorption isotherm

INTERNATIONAL JOURNAL OF ENERGY RESEARCH, Issue 1 2005
X. J. Zhang
Abstract In this paper a family of new silica gel,calcium chloride composite adsorbents is presented for desiccant rotary wheel in dehumidification system. For these desiccants the water sorption equilibrium has been measured in a wide relative vapour pressure range. This experimental study shows that the vapour adsorption properties of the composites using calcium chloride as impregnated salt can be controllably modified by varying the amount of the salt inside the pores. The thermodynamic performance of such desiccant rotary wheel is analysed based on the adsorption equilibrium equations obtained through nonlinear regressions using fractal BET theory. The simulation results show that the new composite desiccants can be effectively used in a rotary wheel dehumidifier and to improve its performance, various optimum operational/system parameters have been identified. Copyright © 2005 John Wiley & Sons, Ltd. [source]

Preparation and adsorption properties of chitosan,poly(acrylic acid) nanoparticles for the removal of nickel ions

JOURNAL OF APPLIED POLYMER SCIENCE, Issue 4 2008
Jian-Wen Wang
Abstract Chitosan (CS) nanoparticles with different mean sizes ranging from 100 to 195 nm were prepared by ionic gelation of CS and poly(acrylic acid) (PAA). Variations in the final solution pH value and CS : PAA volume ratio were examined systematically for their effects on nanoparticle size, intensity of surface charge, and tendency toward particle aggregation. The sorption capacity and sorption isotherms of the CS,PAA nanoparticles for nickel ions were evaluated. The parameters for the adsorption of nickel ions by the CS,PAA nanoparticles were also investigated. The CS,PAA nanoparticles could sorb nickel ions effectively. The sorption rate for nickel ions was affected significantly by the initial concentration of the solution, sorbent amount, particle size, and pH value of the solution. The samples of nanoparticles were well correlated with Langmuir's isotherm model, and the adsorption kinetics of nickel correlated well with the pseudo-second-order model. The maximum capacity for nickel sorption deduced from the use of the Langmuir isotherm equation was 435 mg/g, which was significantly higher than that of the micrometer-sized CS. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2008 [source]

Effects of oxidation time on the structure and properties of polyacrylonitrile-based activated carbon hollow fiber

JOURNAL OF APPLIED POLYMER SCIENCE, Issue 1 2007
Junfen Sun
Abstract Polyacrylonitrile (PAN) hollow fibers were pretreated with ammonium dibasic phosphate, then further oxidized in air, carbonized in nitrogen, and activated with carbon dioxide. The effects of oxidation time of PAN hollow fiber precursor on the microstructure, specific surface, pore size distribution, and adsorption properties of PAN-based activated carbon hollow fiber (PAN-ACHF) were studied in this work. Both of specific surface area and adsorption ratio to VB12 reach maximums when PAN hollow fibers are oxidized for 5 h in air. The adsorption ratios for creatinine are all higher than 90% over all oxidation time. After 5 h of oxidation, the number of pores on the surface obviously increases, and the pore size is uniform. After 7 h of oxidation, the number of macropores in PAN-ACHF increases. The dominant pore sizes of mesopores in PAN-ACHF range from 2 to 5 nm. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2007 [source]

Material design using molecular modeling for hydrogen storage

AICHE JOURNAL, Issue 2 2009
F. Darkrim Lamari
Abstract Using grand canonical Monte-Carlo simulations, the adsorption capacities and isosteric heats of hydrogen on activated carbons, graphite nanofibers, and bundles of carbon nanotubes are estimated for identical thermodynamic states. These computations allow a systematic, meaningful, and unbiased comparison of the adsorption properties of hydrogen in such porous materials. The comparison shows that the hydrogen storage capacity can be optimized, but only to a limited extent, in adjusting the material pore sizes and functionalizing a part of the adsorption sites. Therefore, at room temperature and up to 70.0 MPa, for the three models of carbonaceous adsorbents, the hydrogen maximal excess adsorption is of the order of 2% of the adsorbent mass. © 2009 American Institute of Chemical Engineers AIChE J, 2009 [source]

A simple automated method of quantitative characterization of foam behaviour,

POLYMER INTERNATIONAL, Issue 4 2003
Dr Klaus Lunkenheimer
Abstract There are various methods available to measure foam stability. However, their main drawback is that their results are hardly comparable because definite boundary conditions are missing. One particular disadvantage is that there is no method which is applicable to systems of very low (transient or ,wet' foams) as well as of very high (metastable or ,dry' foams) foam stability. Here, we put forward a novel automatic, pneumatic method that is applicable to both systems. Its principle relies on the measurement of the foam produced by dispersing a definite amount of gas in a definite volume of solution at constant gas velocity. Foam and draining solution are determined simultaneously. This method has advantages over all other methods in several respects such as: (1) it represents a simple and definite procedure under well-defined boundary conditions, (2) it is generally applicable to all kinds of foam, and (3) it provides new standard parameters for the quantitative characterization of foamability and foam stability. The standard parameters can be related to the basic adsorption properties and the structure of the surfactant. The method's capability is demonstrated with three different non-ionic and ionic surfactants belonging to the wet (n-octanoic acid) and dry foam systems (n-nonyl-,- D -glucopyranoside and sodium dodecylsulfate). Copyright © 2003 Society of Chemical Industry [source]

Surface properties of poly(lactic/glycolic acid),pluronic® blend films

POLYMERS FOR ADVANCED TECHNOLOGIES, Issue 11-12 2003
É. Kiss
Abstract Poly(dl -lactide) (PLA) and two of its random copolymers with glycolic acid, poly(dl -lactide- co -glycolide) (PLGA) with 75/25 and 50/50 component ratios of lactide/glycolide were blended with poly(ethylene oxide)/poly(propylene oxide)/poly(ethylene oxide) (PEO,PPO,PEO) triblock non-ionic surfactants, known by the Pluronic® trade names of PE6100, PE6400 and PE6800. The surface chemical compositions of the blended films were identified by X-ray photoelectron spectroscopy (XPS). Based on the component of the carbon signal assigned to the ether carbon of the Pluronic® molecule, quantification of the surface accumulation of the Pluronic® additive, compared to its bulk concentration, was performed. The data demonstrated that PEO-containing surfaces were prepared by the blending process. A significant surface hydrophilization, characterized by wettability measurements, was obtained by applying the Pluronics® at a concentration of 1.0,9.1,wt% in the blends. The composition of the surface layer and, in accordance with this, the wettability of the film were found to be dependent on the type of Pluronic® and on the composition of the unmodified polymer. Protein adsorption on the polymer films was measured by the FT-IR ATR spectroscopic technique. The adsorbed amount of bovine serum albumin onto PLA was highly reduced when the polymer was blended with a Pluronic®. The increased hydrophilicity and the reduced protein adsorption properties of the PLA and PLGA obtained by blending with PEO compounds might contribute to their applications as drug carrier systems with great potential. Copyright © 2003 John Wiley & Sons, Ltd. [source]

Molecular-selective adsorption property of chemically surface modified nanoporous alumina membrane by di(1-naphthyl)silanediol to anthracenes

APPLIED ORGANOMETALLIC CHEMISTRY, Issue 3 2010
Kenji Kakiage
Abstract Nano-porous alumina membrane (NPAM) formed by the anodic oxidation of aluminum is an attractive composite as the base material for a functional filter, because of its honeycombed ordered structure with large surface area per weight and also high shape stability. In this work, we investigated the adsorption properties of the NPAM possessing ,-electron systems on the surface, which were produced through chemical surface modification by di(1-naphthyl)silanediol, to aromatic compounds using anthracenes as typical aromatic compounds. The chemically surface-modified NPAM exhibited strong affinity to anthracene molecules and the affinity was observed to be weakened remarkably with the introduction of methyl and phenyl substituents to anthracene, indicating a molecular-selective adsorption property of the NPAM. Copyright © 2009 John Wiley & Sons, Ltd. [source]

Determination of physical behaviour of feed pellets in Mediterranean water

AQUACULTURE RESEARCH, Issue 2 2006
Paolo Vassallo
Abstract Settled uneaten feed causes the most intense impact under sea cages, and settling velocity of the feed pellets represents a key parameter for waste dispersion models. Even if some data about physical properties of feed pellets have been published in the framework of salmonid rearing, there is a complete lack of information related to the Mediterranean Sea, as regards typical values of temperature, salinity and feed composition for Gilthead Sea Bream (Sparus aurata L.) and Sea Bass (Dicentrarchus labrax L.). In this study we try to fill this lack, determining dimensions, water adsorption properties, floating times and settling velocities of a typical growing sequence of pellets for the species mentioned above, under defined laboratory conditions reproducing Mediterranean Sea water. The settling velocity increases with pellet size from 0.087, for the smallest pellet (3 mm), to 0.144 m s,1, for the 5 mm pellet. The biggest extruded pellet (6 mm) falls slower (0.088 m s,1). The floating time before pellet's fall is found to be a critical parameter in determining settling velocity. The latter depends on pellet's size, water temperature and salinity. The examined pellets reach a 42% of weight increase after 10 min of immersion, while no appreciable dimension change is observed. Our results are in part different from previous ones and could play a role in evaluating and modelling Mediterranean aquaculture environmental impact. [source]

Adsorption properties of microwave synthesized inorgano,organo montmorillonite

Protein adsorption at air,water interfaces: A combination of details

BIOPOLYMERS, Issue 1-2 2004
Harmen H. J. de Jongh
Abstract Using a variety of spectroscopic techniques, a number of molecular functionalities have been studied in relation to the adsorption process of proteins to air,water interfaces. While ellipsometry and drop tensiometry are used to derive information on adsorbed amount and exerted surface pressure, external reflection circular dichroism, infrared, and fluorescence spectroscopy provide, next to insight in layer thickness and surface layer concentration, molecular details like structural (un)folding, local mobility, and degree of protonation of carboxylates. It is shown that the exposed hydrophobicity of the protein or chemical reactivity of solvent-exposed groups may accelerate adsorption, while increased electrostatic repulsion slows down the process. Also aggregate formation enhances the fast development of a surface pressure. A more bulky appearance of proteins lowers the collision intensity in the surface layer, and thereby the surface pressure, while it is shown to be difficult to affect protein interactions within the surface layer on basis of electrostatic interactions. This work illustrates that the adsorption properties of a protein are a combination of molecular details, rather than determined by a single one. © 2004 Wiley Periodicals, Inc. Biopolymers, 2004 [source]

A Novel Magnetic Affinity Support for Protein Adsorption and Purification

BIOTECHNOLOGY PROGRESS, Issue 1 2001
Xiao-Dong Tong
A novel magnetic support was prepared by an oxidization-precipitation method with poly(vinyl alcohol) (PVA) as the entrapment material. Transmission electron microscopy indicated that the magnetic particles had a core-shell structure, containing many nanometer-sized magnetic cores stabilized by the cross-linked PVA. The particles showed a high magnetic responsiveness in magnetic field, and no aggregation of the particles was observed after the particles had been treated in the magnetic field. These facts indicated that the particles were superparamagnetic. Cibacron blue 3GA (CB) was coupled to the particles to prepare a magnetic affinity support (MAS) for protein adsorption. Lysozyme was used as a model protein to test the adsorption properties of the MAS. The adsorption equilibrium of lysozyme to the MAS was described by the Langmuir-type isotherm. The capacity for lysozyme adsorption was more than 70 mg/g MAS (wet weight) at a relatively low CB coupling density (3,5 ,mol/g). In addition, 1.0 M NaCl solution could be used to dissociate the adsorbed lysozyme. Finally, the MAS was recycled for the purification of alcohol dehydrogenase (ADH) from clarified yeast homogenates. Under proper conditions, the magnetic separation yielded over 5-fold purification of the enzyme with 60% recovery of the enzyme activity. [source]

Confinement in Nanopores at the Oxide/Water Interface: Modification of Alumina Adsorption Properties

Mechanism of Charging of Au Atoms and Nanoclusters on Li Doped SiO2/Mo(112) Films

CHEMPHYSCHEM, Issue 2 2010
Umberto Martinez Dr.
Abstract We present the results of supercell DFT calculations on the adsorption properties of Au atoms and small clusters (Aun, n,5) on a SiO2/Mo(112) thin film and on the same system modified by doping with Li atoms. The adsorbed Li atoms penetrate into the pores of the silica film and become stabilized at the interface where they donate one electron to the Mo metal. As a consequence, the work function of the Li-doped SiO2/Mo(112) film is reduced and results in modified adsorption properties. In fact, while on the undoped SiO2/Mo(112) film Au interacts only very weakly, on the Li-doped surface Au atoms and clusters bind with significant bond strengths. The calculations show that this is due to the occurrence of an electron transfer from the SiO2/Mo(112) interface to the adsorbed gold. The occurrence of the charge transfer is related to the work function of the support but also to the possibility for the silica film to undergo a strong polaronic distortion. [source]