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Sample records for aromatiques polycycliques adsorbes

  1. Les hydrocarbures aromatiques polycycliques dans l'environnement : la réhabilitation des anciens sites industriels The Polycyclic Aromatic Hydrocarbons in the Environment : the Former Industrial Sites Remediation

    OpenAIRE

    Costes J. M.; Druelle V.

    2006-01-01

    Les hydrocarbures aromatiques polycycliques ou HAP peuvent être d'origine naturelle mais ils proviennent principalement des processus de pyrolyse. On peut les retrouver dans les sols de certains anciens sites industriels. Cela peut être le cas des sites d'anciennes usines à gaz. Même si aucune conséquence sur la santé humaine n'a été signalée et même si les risques paraissent virtuels, le principe de précaution rend nécessaire de s'occuper des risques liés à ces anciens sites industriels. Gaz...

  2. Les hydrocarbures aromatiques polycycliques dans l'environnement : la réhabilitation des anciens sites industriels The Polycyclic Aromatic Hydrocarbons in the Environment : the Former Industrial Sites Remediation

    Directory of Open Access Journals (Sweden)

    Costes J. M.

    2006-12-01

    Full Text Available Les hydrocarbures aromatiques polycycliques ou HAP peuvent être d'origine naturelle mais ils proviennent principalement des processus de pyrolyse. On peut les retrouver dans les sols de certains anciens sites industriels. Cela peut être le cas des sites d'anciennes usines à gaz. Même si aucune conséquence sur la santé humaine n'a été signalée et même si les risques paraissent virtuels, le principe de précaution rend nécessaire de s'occuper des risques liés à ces anciens sites industriels. Gaz de France, propriétaire de 467 sites d'anciennes usines à gaz assume l'héritage industriel dans le cadre d'un protocole signé avec le ministère de l'Environnement. Après une étude des sols, une évaluation des risques est réalisée. En fonction des résultats de cette évaluation des risques et de l'usage du site (actuel et prévu, des solutions de traitement peuvent être mises en Suvre. Parmi les techniques applicables aux sols pollués par des HAP, un intérêt particulier s'est porté sur les traitements biologiques, en pleine évolution, qui offrent une solution économique bien adaptée au traitement de grands volumes de sols souillés par une pollution organique moyennement concentrée. Polycyclic aromatic hydrocarbons (PAHs can be found under natural conditions but they can be produced by pyrolysis processes. They can be found in former industrial sites subsoil, especially on Manufactured Gas Plant sites (MGP sites. Gaz de France has inherited the patrimony of former French gas companies on nationalisation in 1946; consequently, Gaz De France is still the owner of 467 of manufactured gas plants. Even if no impact on human health has been detected and even if the risks seem to be virtual, Gaz de France has to prevent any environmental consequence due to the possible presence of residues in the subsoil of the sites: a protocol has been signed with the French Ministry of Environment. Following the investigations on the site, a

  3. Les hydrocarbures aromatiques polycycliques dans l'environnement. Deuxième partie : La dégradation par voie microbienne Polycyclic Aromatic Hydrocarbons in the Environment. Part Two: Microbial Degradation

    Directory of Open Access Journals (Sweden)

    Bouchez M.

    2006-11-01

    Full Text Available La microbiologie de la dégradation des hydrocarbures aromatiques polycycliques (HAP est un domaine de recherche en plein développement. C'est à la fois le devenir dans l'environnement de ces composés ubiquistes et génotoxiques et l'utilisation de procédés microbiologiques de dépollution des sols industriels contaminés par ces produits qui motivent cet intérêt. On présente ici une synthèse des connaissances actuelles dans ce domaine. Les organismes dégradeurs sont essentiellement les bactéries et les champignons. Le processus de dégradation, aérobie, est initié par des oxygénases. Les bactéries utilisent les HAP de deux à quatre cycles comme substrats de croissance, ce qui conduit à leur minéralisation. Les champignons, lignolytiques et non lignolytiques, attaquent les HAP par cométabolisme, ce que font également les bactéries. L'ensemble des micro-organismes dégradant les HAP, et les voies métaboliques impliquées, sont présentés. Le mode d'accession des micro-organismes à leurs substrats très peu solubles est un point important. Les études menées avec les bactéries ont montré l'existence de deux mécanismes, le transfert par solubilisation dans la phase aqueuse et l'accession interfaciale directe. Un autre aspect présenté est le devenir des HAP, en termes de bilans carbone, lors de la dégradation bactérienne de HAP individuels et de mélanges de HAP. Des taux de minéralisation élevés peuvent être obtenus. Dans le cas des mélanges, ces taux élevés impliquent la mise en oeuvre de microflores complexes où le cométabolisme joue un rôle important. Les progrès accomplis ces dernières années conduisent à ne plus considérer les HAP comme des composés intrinsèquement récalcitrants à la biodégradation. Dans l'environnement, un facteur important limitant la dégradation des HAP est leur accessibilité aux micro-organismes. The microbiology of the degradation of polycyclic aromatic hydrocarbons

  4. Fenton's reagent as a remediation process in water treatment: application to the degradation of polycyclic aromatic hydrocarbons in waters and sewage sludges; La reaction de fenton comme procede de rehabilitation dans le traitement des eaux: application a la degradation des hydrocarbures aromatiques polycycliques dans les eaux et les boues residuaires

    Energy Technology Data Exchange (ETDEWEB)

    Flotron, V.

    2004-05-15

    This study is related to the application of Fenton's reagent to remedy matrices contaminated by polycyclic aromatic hydrocarbons (PAHs). In aqueous solution, the choice of the reagent implementation is important, in order to generate enough radicals to oxidize pollutants. Degradation of the organic compounds is possible, but a large difference in reactivity is observed between 'alternant' and 'non-alternant' PAHs (with a five carbon atoms cycle). Besides, if a few specific precautions are omitted, the PAHs can sorb onto the flask inside surface, and therefore not undergo oxidation. The results on sewage sludges show that under certain conditions (high reagent concentrations), the pollutants can be oxidised although they are adsorbed. Moreover, it appears that the matrix itself plays an important role, as the iron oxides seem to be able to decompose hydrogen peroxide, and thus initiate Fenton reaction. Its application to contaminated soils and sediments is also possible. (author)

  5. Filtration d’une huile dopée avec quatre hydrocarbures aromatiques polycycliques (HAP sur des plaques garnies en charbon actif

    Directory of Open Access Journals (Sweden)

    Sidani Marion

    2012-11-01

    Full Text Available Powdered activated carbon is used in oils and fats refining to bleach and purify vegetable oils and fish oils. Actually, this powder makes it possible to detoxify crude fish oils and to eliminate contaminants like PAH, dioxin and PCB. Nevertheless, the powdered activated carbon used is painful because it is pulverulent. Nowadays, producers advise filtration plates filled with this powder. The aim of this study is to check the efficiency of such plates in the PAH elimination and verify the respect of the new 2011 regulation (2 μg/kg for benzo(apyrene, 10 μg/kg for the sum of benzo(apyrene, benzo(bfluoranthene, benzo (aanthracene and chrysene.

  6. Aromatic polycyclic hydrocarbons in the environment - I - Sources. Les hydrocarbures aromatiques polycycliques chlores presents dans l'environnement - I - Sources

    Energy Technology Data Exchange (ETDEWEB)

    Bard, D. (Electricite de France (EDF), 75 - Paris (France))

    Chlorinated aromatic polycyclic hydrocarbons, which include polychlorinated dibenzo-p-dioxins (PCDDs), polychlorinated dibenzofurans (PCDFs), polychlorobiphenyls (PCBs) and others, are persistent, ubiquitous compounds in the environment of industrialized countries. In this paper, we present a short review of the known sources of these compounds. These include industrial sources, such as processing, accidents, and waste disposal of chlorophenols, diphenylethers herbicides, chlorinated aliphatics and PCBs processing: petroleum refining industry, municipal and industrial waste incineration; reclamation or recycling of copper and steel; pulp and paper cork, pesticides (hexachlorocyclohexanes-HCH) and metallurgical (nickel and magnesium) processing. In addition, these compounds appear as being formed naturally in traces quantities in many circumstances of organic matter combustion or pyrolysis. As a result, they have been found in chimney soots, stoves... They are also produced in car exhausts. Another natural mechanism of formation could be the photochemical degradation of higher chlorinated isomers to lower ones. Since it cannot be excluded that these compounds may be carcinogenic for humans at low doses, efforts should be made to limit to as low as reasonably achievable the inputs to the environment of HAPC from artificial origin. (Author). 46 refs., 8 tabs.

  7. Filtration d’une huile dopée avec quatre hydrocarbures aromatiques polycycliques (HAP) sur des plaques garnies en charbon actif

    OpenAIRE

    Sidani Marion; Gaud Marie; Pagès Xavier; Morin Odile; Gouband Morgan; Buchoux Jérôme; Goulet Jérémy; Birot Céline; Galan Virginie

    2012-01-01

    Powdered activated carbon is used in oils and fats refining to bleach and purify vegetable oils and fish oils. Actually, this powder makes it possible to detoxify crude fish oils and to eliminate contaminants like PAH, dioxin and PCB. Nevertheless, the powdered activated carbon used is painful because it is pulverulent. Nowadays, producers advise filtration plates filled with this powder. The aim of this study is to check the efficiency of such plates in the PAH elimination and verify the res...

  8. Caractérisation géostatistique de pollutions industrielles de sols: cas des hydrocarbures aromatiques polycycliques sur d'anciens sites de cokeries

    OpenAIRE

    Jeannée, Nicolas

    2001-01-01

    Estimating polycyclic aromatic hydrocarbons concentrations in soil at former industrial sites poses several practical problems on account of the properties of the contaminants and the history of site : - collection and preparation of samples from highly heterogeneous material, - high short scale variability, particularly in presence of backfill, - highly contrasted grades making the variogram inference complicated. The sampling strategy generally adopted for contamined sites is based on the h...

  9. Diagnostic de sols pollués par des hydrocarbures aromatiques polycycliques (HAP) a l'aide de la spectrophotométrie UV.

    OpenAIRE

    Crone, Magalie

    2001-01-01

    Polycyclic aromatic hydrocarbons (PAHs) were produced by many pyrolitic or combustion processes. They were found in soils, often in high concentrations. Remediation of indu striai sites contaminated by P AHs requires an initial diagnosis of the pollution. In this perspective, an analytical procedure based on UV spectrophotometry was developped and validated with about 80 soil samples. Different exploitation methods of the samples UV spectra enable to develop simple and rapid characterisation ...

  10. Approche alternative du lavage de sols pollués par des hydrocarbures aromatiques polycycliques : utilisation des cyclodextrines avec procédés de recyclage

    OpenAIRE

    Viglianti, Christophe

    2007-01-01

    Manufactured Gas Plants sites are mostly contaminated by Polycyclic Aromatic Hydrocarbons (PAHs) under the form of hydrophobic coal tar. Soil washing often uses surfactants or organic solvents, which have a significant environmental impact. This PhD work proposes an alternative way, based on seminatural, non-toxic and easily biodegradable cage-like molecules, β-cyclodextrins. They are able to solubilize hydrophobic molecules, as PAHs, thus extracted them from soil. In order to minimize produc...

  11. Synthèse de composés aromatiques polycycliques distordus par réaction de Scholl vers des nanorubans de carbone courbés

    OpenAIRE

    Pradhan, Anirban

    2013-01-01

    Carbon nanoribbons are today of great interest as graphene segments with modulable electronic properties. Whilst top down techniques give giant ribbons, bottom-up organic synthesis may lead to exactly designed nanoribbons of controlled geometries. The Scholl reaction is a precious chemical tool for that purpose since it yields efficiently to the graphitization of long and flexible polyphenylene precursors.Surprisingly, twisted structures may be obtained preferentially even if less crowded iso...

  12. Diagnosis of soils polluted by aromatic hydrocarbons; Diagnostic de sols pollues par des hydrocarbures aromatiques polycycliques (HAP) a l'aide de la spectrophotometrie UV

    Energy Technology Data Exchange (ETDEWEB)

    Crone, M.

    2000-01-28

    Polycyclic aromatic hydrocarbons (PAHs) were produced by many pyrolytic or combustion processes. They were found in soils, often in high concentrations. Remediation of industrial sites contaminated by PAHs requires an initial diagnosis of the pollution. In this perspective, an analytical procedure based on UV spectrophotometry was developed and validated with about 80 soil samples. Different exploitation methods of the samples UV spectra enable to develop simple and rapid characterisation tools. A PAH UV index is proposed for the estimation of global PAH concentration. A more accurate exploitation of the spectra gives an indication on the presence or the absence of some individual PAH like benzo[a]pyrene. A maturity index based on a two wavelength approach constitutes an indicator of the potential evolution of soil contamination in natural conditions. Laboratory methodology was adapted to field analyses and a test kit was designed for this purpose. The test duration is 20 minutes. (author)

  13. Bioavailability of Polycyclic Aromatic Hydrocarbons in aquatic ecosystems : influence of natural and anthropic organic matter; Biodisponibilite des hydrocarbures aromatiques polycycliques dans les ecosystemes aquatiques: influence de la matiere organique naturelle et anthropique

    Energy Technology Data Exchange (ETDEWEB)

    Gourlay, C.

    2004-11-01

    Aquatic ecosystems receive micro-pollutants. They also contain organic matter (OM) of natural and anthropogenic origins. The contaminant bioavailability in aquatic media is determined by the interactions between contaminants and OM. This work deals with the influence of organic matter from anthropogenic media on the bioavailability of hydrophobic organic pollutants. Polycyclic Aromatic Hydrocarbons (PAHs) have been used as model contaminants, since they are widely spread in urban media. In anthropogenic media, some OM may be bio-degraded. Up to now, most researches focused on the interactions between contaminants and humic OM that are mostly non-degradable, using physico-chemical characterizations of OM. On the contrary, in this work, the biodegradability of OM was deliberately taken into account. Indeed, we assume that the contaminant affinity for OM evolves during OM biodegradation, so that pollutants may be released in a bio-available form and then may be bond again by biodegradation sub-products. In laboratory evaluation, PAH bioavailability was assessed through the measurements of the bioaccumulation in Daphnia magna. The influence of organic matter on the bioavailability of PAHs and the evolution of this influence along OM bacterial mineralization were proved, as well as the strong binding efficiency of degradation by-products. A model of observed phenomena was elaborated. These observations about urban and natural OM effect were compared to in situ PAH bioavailability measurements in the river Seine basin. In this case, the bioavailability was estimated using Semi-Permeable Membrane Device (SPMD) sampling technique. (author)

  14. The aromatic polycyclic chlorinated hydrocarbons (HAPC) or ''dioxin'' 30 june 2000; Les hydrocarbures aromatiques polycycliques chlores (HAPC) ou ''dioxines'' 30 juin 2000

    Energy Technology Data Exchange (ETDEWEB)

    Coulombier, D.; Plenel, L.

    2000-06-01

    The authors propose in this paper a pocket-book on the dioxin also called HAPC. It presents the emission sources of the dioxin, the population exposed, the effects on the public health, the risk assessment, the dioxin in the food and the environment and the regulation in the domain. (A.L.B.)

  15. Geostatistical characterization of soil pollution at industrial sites Case of polycyclic aromatic hydrocarbons at former coking plants; Caracterisation geostatistique de pollutions industrielles de sols cas des hydrocarbures aromatiques polycycliques sur d'anciens sites de cokeries

    Energy Technology Data Exchange (ETDEWEB)

    Jeannee, N.

    2001-05-15

    Estimating polycyclic aromatic hydrocarbons concentrations in soil at former industrial sites poses several practical problems on account of the properties of the contaminants and the history of site: 1)collection and preparation of samples from highly heterogeneous material, 2) high short scale variability, particularly in presence of backfill, 3) highly contrasted grades making the vario-gram inference complicated. The sampling strategy generally adopted for contaminated sites is based on the historical information. Systematic sampling recommended for geostatistical estimation is often considered to be excessive and unnecessary. Two former coking plants are used as test cases for comparing several geostatistical methods for estimating (i) in situ concentrations and (ii) the probability that they are above a pollution threshold. Several practical and methodological questions are considered: 1) the properties of various estimators of the experimental vario-gram and the validity of the results; 2) the use of soft data, such as historical information, organoleptic observations and semi-quantitative methods, with a view to improve the precision of the estimates; 3) the comparison of standard sampling strategies, taking into account vertical repartition of grades and the history of the site. Multiple analyses of the same sample give an approximation of the sampling error. Short scale sampling shows the difficulty of selecting soils in the absence of a spatial structure. Sensitivity studies are carried out to assess how densely sampled soft data can improve estimates. By using mainly existing models, this work aims at giving practical recommendations for the characterization of soil pollution. (author)

  16. Characterization of arene di-oxygenases involved in polycyclic aromatic hydrocarbons biodegradation in Mycobacterium sp. 6PY1; Caracterisation d'arene dioxygenases impliquees dans la biodegradation des hydrocarbures aromatiques polycycliques chez Mycobacterium sp. 6PY1

    Energy Technology Data Exchange (ETDEWEB)

    Kuony, S.

    2005-06-15

    This thesis deals with the bacterial biodegradation of pollutants called polycyclic aromatic hydrocarbons (PAHs). The bacterium Mycobacterium sp. 6PY1 was isolated from a polluted soil for its ability to use pyrene, a 4-ring PAH, as sole source of carbon and energy. To learn about the pyrene metabolic pathway, the identification of the enzymes involved in this process has been undertaken using a proteomic approach. This approach revealed the occurrence of two ring-hydroxylating di-oxygenases in strain 6PY1, which could catalyze the initial attack of pyrene. The goal of this study was to clone the genes encoding the di-oxygenases identified in Mycobacterium sp. 6PY1, over-express these genes in an heterologous system in order to facilitate the purification of the corresponding enzymes, and determine the biochemical and catalytic properties of these enzymes. The pdoA1B1 genes encoding the terminal component of a di-oxygenase were cloned and over-expressed in Escherichia coli. The catalytic properties of this enzyme, called Pdo1, were determined in vivo by measuring the oxidation products of 2- to 4-ring PAHs by gas chromatography coupled to mass spectrometry (GC-MS). Analysis of the selectivity of the enzyme, as determined using GC-MS, showed that Pdo1 preferentially oxidized 3- or 4-ring PAHs, including phenanthrene and pyrene, but was inactive on di-aromatic compounds such as naphthalene and biphenyl. Pdo1 was unstable and was therefore purified in inactive form. The genes encoding a second di-oxygenase component were found in a locus containing two other catabolic genes. The pdoA2B2 genes encoded an enzyme called Pdo2 showing a narrow specificity towards 2- to 3-ring PAHs, and a high preference for phenanthrene. Pdo2 is an a3{beta}3 hexamer, containing [2Fe-2S] Rieske clusters which confer it a characteristic absorbance spectrum. A third set of genes possibly encoding another di-oxygenase was discovered in the genome of Mycobacterium sp. 6PY1. This set is closely similar in sequence to that encoding Pdo1, suggesting that both isoenzymes are able two oxidize pyrene. In order to function, the ring-hydroxylating di-oxygenases require two electron-transfer proteins: a ferredoxin and a reductase. The electron carriers associated to Pdo1 and Pdo2 were not identified. However, the activity of the two di-oxygenases was stimulated in vivo by co-expressing accessory genes recruited from other bacteria. Finally, immuno-detection experiments using specific antibodies showed that the enzymes Pdo1 and Pdo2 were co-induced in the presence of PAHs, but differentially regulated according to growth conditions. (author)

  17. Re-mobilisation des hydrocarbures aromatiques polycycliques de terres industrielles de cokerie et mécanismes impliqués dans le "vieillissement" du fluoranthène

    OpenAIRE

    Vessigaud, Sandrine

    2007-01-01

    PAH are persistent organic pollutants in soils. In the framework of industrial waste lands rehabilitation, one needs to understand the reasons of their strong retention and to assess their potential for water remobilization. For these purposes, the remobilization potential of industrial polluted matrices was assessed during 6 months in closed reactors with a monthly renewal of the solution. Adsorption / desorption experiments with 14C-fluoranthene on the same matrices and an agricultural soil...

  18. Synthesis of a polycyclic aromatic hydrocarbon marked with carbon-14: (b, d e f) dibenzo-chrysene {sup 14}C-7,14; Synthese d'un hydrocarbure aromatique polycyclique marque au carbone 14: le dibenzo (b, d e f) chrysene {sup 14}C-7,14

    Energy Technology Data Exchange (ETDEWEB)

    Chatelain, G. [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

    1965-07-01

    (b, d e f) dibenzo-chrysene C-7,14 has been synthesized from radioactive carbon dioxide and the organic magnesium compound derived from 1,5 dibromo naphthalene. The product has been purified by a very precise series of fractionated chromatographs on alumina having a chromatographic activity. This has necessitated the development of a special technique. (author) [French] Le dibenzo (b, d e f) chrysene 14C-7,14 a ete synthetise au depart de gaz carbonique radioactif et de bis-organomagnesien derive du dibromo-1,5 naphtalene. Le produit a ete purifie par une serie de chromatographies fractionnees sur alumine d'activite chromatographique tres precise. Ceci a fait l'objet d'une mise au point de technique. (auteur)

  19. Caractérisation et origine des métaux traces, hydrocarbures aromatiques polycycliques et pesticides transportés par les retombées atmosphériques et les eaux de ruissellement dans les bassins versants séparatifs péri-urbains.

    OpenAIRE

    Lamprea, Katerine

    2009-01-01

    Depuis une trentaine d'années, les eaux de ruissellement sont considérées comme une source importante de pollution des milieux naturels en raison de leur concentration élevée en micropolluants. Les dépôts atmosphériques, l'érosion des surfaces imperméables (toitures, chaussées, trottoirs et parkings) et le lessivage des dépôts générés principalement par le transport, les chauffages et les industries sont les principales sources identifiées. L'objectif du travail présenté dans ce mémoire est d...

  20. Influence des solvants aromatiques sur les propriétés optiques du bleu de phtalocyanine de cuivre en milieu pictural

    Directory of Open Access Journals (Sweden)

    Catherine Defeyt

    2010-11-01

    Full Text Available Actuellement, cinq formes de bleu de phtalocyanine de cuivre sont utilisées comme pigments artistiques: PB15, :1, :2, :3, :4, et :6. PB15 qui correspond à la forme la plus utilisée après PB15 :3 est sujette à la cristallisation. Ce phénomène qui s’observe plus particulièrement en présence de solvants aromatiques entraîne un glissement de teinte du bleu vers le vert et une perte du pouvoir couvrant du pigment. Or, l’usage de solvants aromatiques dans le champ de la conservation-restauration de peintures de chevalet est relativement commun. Citons par exemple, le toluène et les xylènes qui entrent dans la composition de certains mélanges de solvants, de certains types vernis (Laropal A81 et d’adhésifs (Beva 371. C'est pourquoi il est nécessaire d’effectuer une recherche de manière à déterminer si les conditions d’utilisation des solvants aromatiques en conservation-restauration provoquent la cristallisation de PB15. Dans cet article, les premiers résultats obtenus sur des échantillons de PB15, :1, :2, :3, :4 et :6 en poudre sont présentés. Les cinq formes susmentionnées ont été examinées sous microscope polarisant et analysées par spectroscopie infrarouge à transformée de Fourier et diffraction de rayons X, avant et après leur immersion dans les solvants aromatiques, de façon à pouvoir comparer les propriétés optiques et chimiques.Currently, five forms of copper phthalocyanine blue, PB15, :1, :2, :3, :4, and :6, are used as artistic pigments. PB15, the most widespread form afterwards PB15:3 is prone to crystallisation. This phenomenon changes the metastable α form into a coarsely crystalline form with an attendant loss of tinctorial strength. Crystal growth can occur in many media but is most often seen in paints containing aromatic solvents. The use of aromatic solvents as part of conservation treatments of paintings is relatively common. For example, the toluene and  the xylenes found

  1. Bio-raffinage de plantes aromatiques et médicinales appliqué à l'Hibiscus sabdariffa L. et à l'Artemisia annua

    OpenAIRE

    Endrias, Abraham

    2006-01-01

    L'objectif de l'étude était d'évaluer les potentialités aromatiques et médicinales de deux plantes (Hibiscus sabdariffa et Artemisia annua). Les performances et rendement de plusieurs méthodes d'extraction et de solvants sur des calices et des graines d'hibiscus, issus de trois pays (Vietnam, Sénégal et Mexique) ont été comparés. Les profils en composés volatifs diffèrent selon les extraits. La teneur en acide gras, stérols et tocophérols des huiles des graines d'hibiscus est comparable à cel...

  2. Petrochemistry - Aromatics; Petrochimie - Aromatiques

    Energy Technology Data Exchange (ETDEWEB)

    Anon.

    2005-09-01

    The assignment of Unipetrol chemical activities to the Czech group Agrofert by the Polish PKN Orlen is suspended and would be renegotiated. Oman Oil Company (OOC) is joining in the Korean LG International and in its subsidiary company Oman Refinery Company (ORC) for the construction of its new aromatics complex on its site of Sohar (Oman). This plan represents an investment of one milliard of dollars; it will produce 800000 t/year of para-xylene and 210000 t/year of benzene. The unit would be operational at the third trimester 2008. (O.M.)

  3. Molecular Adsorber Coating

    Science.gov (United States)

    Straka, Sharon; Peters, Wanda; Hasegawa, Mark; Hedgeland, Randy; Petro, John; Novo-Gradac, Kevin; Wong, Alfred; Triolo, Jack; Miller, Cory

    2011-01-01

    A document discusses a zeolite-based sprayable molecular adsorber coating that has been developed to alleviate the size and weight issues of current ceramic puck-based technology, while providing a configuration that more projects can use to protect against degradation from outgassed materials within a spacecraft, particularly contamination-sensitive instruments. This coating system demonstrates five times the adsorption capacity of previously developed adsorber coating slurries. The molecular adsorber formulation was developed and refined, and a procedure for spray application was developed. Samples were spray-coated and tested for capacity, thermal optical/radiative properties, coating adhesion, and thermal cycling. Work performed during this study indicates that the molecular adsorber formulation can be applied to aluminum, stainless steel, or other metal substrates that can accept silicate-based coatings. The coating can also function as a thermal- control coating. This adsorber will dramatically reduce the mass and volume restrictions, and is less expensive than the currently used molecular adsorber puck design.

  4. Regenerative adsorbent heat pump

    Science.gov (United States)

    Jones, Jack A. (Inventor)

    1991-01-01

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

  5. High performance Mo adsorbent PZC

    Energy Technology Data Exchange (ETDEWEB)

    Anon.

    1998-10-01

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

  6. Substrate-adsorbate coupling in CO-adsorbed copper

    CERN Document Server

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

    1996-01-01

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

  7. Black Sprayable Molecular Adsorber Coating Project

    Data.gov (United States)

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

  8. Protein purification using magnetic adsorbent particles

    DEFF Research Database (Denmark)

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

    2006-01-01

    The application of functionalised magnetic adsorbent particles in combination with magnetic separation techniques has received considerable attention in recent years. The magnetically responsive nature of such adsorbent particles permits their selective manipulation and separation in the presence...... of development of protein separation using magnetic adsorbent particles and identify the obstacles that must be overcome if protein purification with magnetic adsorbent particles is to find its way into industrial practice....... of other suspended solids. Thus, it becomes possible to magnetically separate selected target species directly out of crude biological process liquors (e.g. fermentation broths, cell disruptates, plasma, milk, whey and plant extracts) simply by binding them on magnetic adsorbents before application...

  9. A novel fiber-based adsorbent technology

    Energy Technology Data Exchange (ETDEWEB)

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

    1997-10-01

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

  10. Filter-adsorber aging assessment

    International Nuclear Information System (INIS)

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

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

    OpenAIRE

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

    1994-01-01

    An expression is obtained for the current in scanning tunneling microscopy (STM) for a single adsorbate molecule. For this purpose the ``Newns–Anderson'' treatment (a ``discrete state in a continuum'' treatment) is used to obtain wave functions and other properties of the adsorbate/substrate system. The current is expressed in terms of the adsorbate–tip matrix elements, and an effective local density of states of the adsorbate/substrate system, at the adsorbate. As an example, the treatment i...

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2014-04-30

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

  13. NOx adsorber and method of regenerating same

    Science.gov (United States)

    Endicott, Dennis L.; Verkiel, Maarten; Driscoll, James J.

    2007-01-30

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

  14. Nanovalved Adsorbents for CH4 Storage.

    Science.gov (United States)

    Song, Zhuonan; Nambo, Apolo; Tate, Kirby L; Bao, Ainan; Zhu, Minqi; Jasinski, Jacek B; Zhou, Shaojun J; Meyer, Howard S; Carreon, Moises A; Li, Shiguang; Yu, Miao

    2016-05-11

    A novel concept of utilizing nanoporous coatings as effective nanovalves on microporous adsorbents was developed for high capacity natural gas storage at low storage pressure. The work reported here for the first time presents the concept of nanovalved adsorbents capable of sealing high pressure CH4 inside the adsorbents and storing it at low pressure. Traditional natural gas storage tanks are thick and heavy, which makes them expensive to manufacture and highly energy-consuming to carry around. Our design uses unique adsorbent pellets with nanoscale pores surrounded by a coating that functions as a valve to help manage the pressure of the gas and facilitate more efficient storage and transportation. We expect this new concept will result in a lighter, more affordable product with increased storage capacity. The nanovalved adsorbent concept demonstrated here can be potentially extended for the storage of other important gas molecules targeted for diverse relevant functional applications. PMID:27124722

  15. Impact des communautés microbiennes sur la dynamique de dégradation de micropolluants organiques au sein d’écosystèmes épuratoires et sur l’expression de leur toxicité

    OpenAIRE

    Braun, Florence

    2012-01-01

    Les activités anthropiques génèrent une contamination à de faibles doses des boues de station d’épuration par des micropolluants organiques persistants tels que les hydrocarbures aromatiques polycycliques (HAP), les polychlorobiphényles et le nonylphénol. Cette étude porte sur la détermination de l’influence des microorganismes au cours de la méthanisation sur le devenir de ces trois familles de micropolluants. Un protocole spécifique a été mis au point pour extraire des microorganismes de le...

  16. Inorganic chemically active adsorbents (ICAAs)

    Energy Technology Data Exchange (ETDEWEB)

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

    1997-10-01

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

  17. Heat transfer to the adsorbent in solar adsorption cooling device

    Science.gov (United States)

    Pilat, Peter; Patsch, Marek; Papucik, Stefan; Vantuch, Martin

    2014-08-01

    The article deals with design and construction of solar adsorption cooling device and with heat transfer problem in adsorber. The most important part of adsorption cooling system is adsorber/desorber containing adsorbent. Zeolith (adsorbent) type was chosen for its high adsorption capacity, like a coolant was used water. In adsorber/desorber occur, at heating of adsorbent, to heat transfer from heat change medium to the adsorbent. The time required for heating of adsorber filling is very important, because on it depend flexibility of cooling system. Zeolith has a large thermal resistance, therefore it had to be adapted the design and construction of adsorber. As the best shows the tube type of adsorber with double coat construction. By this construction is ensured thin layer of adsorbent and heating is quick in all volume of adsorbent. The process of heat transfer was experimentally measured, but for comparison simulated in ANSYS, too.

  18. States of water adsorbed on perindopril crystals

    Science.gov (United States)

    Stepanov, V. A.; Khmelevskaya, V. S.; Bogdanov, N. Yu.; Gorchakov, K. A.

    2011-10-01

    The relationship between the structural state of adsorbed water, the crystal structure of the substances, and the solubility of the perindopril salt C19H32N2O5 · C4H11N in water was studied by IR spectroscopy and X-ray diffractometry. The high-frequency shift of the stretching vibrations of adsorbed water and the solubility depend on the crystal structure of the drug substance. A reversible chemical reaction occurred between the adsorbed water and the perindopril salt.

  19. New liquid waste control with tannin adsorbent

    International Nuclear Information System (INIS)

    Since 1971, the Mitsubishi Nuclear Fuel Co., Ltd. (MNF) has been fabricating PWR fuels and developing related technology and processes. In the UF6 reconversion lines of MNF, the ammonium diuranate (ADU) process has been operating and the newly developed process of liquid waste treatment was installed last year. The characteristic of this process is to use insoluble tannin adsorbent which has been developed by MNF. The tannin adsorbent is not only an effective means to adsorb heavy metals such as uranium and plutonium but is also easy to incinerate at low temperature. Control of radioactive liquid waste from nuclear facilities is generally implemented by co-precipitation. However, it produces secondary wastes such as noncombustible materials which include radionuclides and it is anticipated that the storage and disposal of those wastes will be at high cost. Those are the reasons why tannin adsorbent has an advantage, and why MNF develops it. (author)

  20. IR investigations of surfaces and adsorbates

    CERN Document Server

    Gwyn, W

    2001-01-01

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

  1. ADSORBENTS USED IN THE CLEARANCE OF ENDOTOXIN

    Institute of Scientific and Technical Information of China (English)

    YU Mei; LIU Tao; Hou Guanghui; YUAN Zhi

    2003-01-01

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

  2. Mesoporous Silica: A Suitable Adsorbent for Amines

    Directory of Open Access Journals (Sweden)

    Abdollahzadeh-Ghom Sara

    2009-01-01

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

  3. Behavior of macromolecules in adsorbed layers

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

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

  4. Hydrophobic Porous Material Adsorbs Small Organic Molecules

    Science.gov (United States)

    Sharma, Pramod K.; Hickey, Gregory S.

    1994-01-01

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

  5. Dissolved Air Flotation of arsenic adsorbent particles

    Directory of Open Access Journals (Sweden)

    M. Santander

    2015-04-01

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

  6. Photochemistry of Nitrate Adsorbed on Mineral Dust

    Science.gov (United States)

    Gankanda, A.; Grassian, V. H.

    2013-12-01

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

  7. 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

  8. Novel Fiber-Based Adsorbent Technology; FINAL

    International Nuclear Information System (INIS)

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

  9. Black Molecular Adsorber Coatings for Spaceflight Applications

    Science.gov (United States)

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

    2014-01-01

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

  10. Size selective hydrophobic adsorbent for organic molecules

    Science.gov (United States)

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

    1997-01-01

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

  11. Defluoridization Using a Natural Adsorbent, Strychnos Potatorum

    Directory of Open Access Journals (Sweden)

    S.Rayappan

    2014-10-01

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

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

    International Nuclear Information System (INIS)

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

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

    KAUST Repository

    Chakraborty, Anutosh

    2009-07-07

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

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

    Institute of Scientific and Technical Information of China (English)

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

    2014-01-01

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

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

    Science.gov (United States)

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

    1988-01-01

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

  16. Organosilicon Ion-Exchange and Complexing Adsorbents

    Institute of Scientific and Technical Information of China (English)

    M. Voronkov; N. Vlasova; Yu. Pozhidaev; L. Belousova

    2005-01-01

    @@ 1Introduction Modification of mineral synthetic or natural substrates by organosilicon G-functionally substituted monomers, copolycondensation of the latter with organic and organosilicon compounds, and hydrolytic polycondensation of these monomers are the most widely used methods of synthesis of organosilicon adsorbents.

  17. Radon emanation from radium specific adsorbents.

    Science.gov (United States)

    Alabdula'aly, Abdulrahman I; Maghrawy, Hamed B

    2010-01-01

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

  18. The Dynamics and Structures of Adsorbed Surfaces

    DEFF Research Database (Denmark)

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

    1978-01-01

    Reviews neutron scattering work performed on films of simple gas atoms and molecules adsorbed primarily on graphite surfaces. Exfoliated graphite substrates such as Grafoil were first used in this kind of measurements about five years ago and new results have been reported at an increasing pace. ...

  19. Le transfert des micropolluants organiques dans la chaîne alimentaire Etat et perspectives de recherche

    Directory of Open Access Journals (Sweden)

    Feidt Cyril

    2000-09-01

    Full Text Available Les hydrocarbures aromatiques polycycliques ont récemment défrayé la chronique à plusieurs reprises. Cet article se propose de faire le point sur les propriétés de ces molécules en vue de donner un aperçu des voies pour la recherche d’outils d’évaluation et de gestion des risques liés à ces molécules. De nombreuses molécules peuvent prétendre appartenir à cette famille. Nous traiterons de celles les plus communément impliquées dans les problèmes de sécurité alimentaire, à savoir la famille des dioxines-furanes ou polychloro-dibenzo-paradioxines/furanes (PCDD/F, celle des composés polychlorés biphényles (PCB et enfin celle des hydrocarbures aromatiques polycycliques (HAP que nous réserverons dans ce texte aux composés non chlorés.

  20. Development and Testing of Molecular Adsorber Coatings

    Science.gov (United States)

    Abraham, Nithin; Hasegawa, Mark; Straka, Sharon

    2012-01-01

    The effect of on-orbit molecular contamination has the potential to degrade the performance of spaceflight hardware and diminish the lifetime of the spacecraft. For example, sensitive surfaces, such as optical surfaces, electronics, detectors, and thermal control surfaces, are vulnerable to the damaging effects of contamination from outgassed materials. The current solution to protect these surfaces is through the use of zeolite coated ceramic adsorber pucks. However, these pucks and its additional complex mounting hardware requirements result in several disadvantages, such as size, weight, and cost related concerns, that impact the spacecraft design and the integration and test schedule. As a result, a new innovative molecular adsorber coating was developed as a sprayable alternative to mitigate the risk of on-orbit molecular contamination. In this study, the formulation for molecular adsorber coatings was optimized using various binders, pigment treatment methods, binder to pigment ratios, thicknesses, and spray application techniques. The formulations that passed coating adhesion and vacuum thermal cycling tests were further tested for its adsorptive capacity. Accelerated molecular capacitance tests were performed in an innovatively designed multi-unit system containing idealized contaminant sources. This novel system significantly increased the productivity of the testing phase for the various formulations that were developed. Work performed during the development and testing phases has demonstrated successful application of molecular adsorber coatings onto metallic substrates, as well as, very promising results for the adhesion performance and the molecular capacitance of the coating. Continued testing will assist in the qualification of molecular adsorber coatings for use on future contamination sensitive spaceflight missions.

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

    DEFF Research Database (Denmark)

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

    1998-01-01

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

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

    Institute of Scientific and Technical Information of China (English)

    1999-01-01

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

  3. Zeolites as alcohol adsorbents from aqueous solutions

    Directory of Open Access Journals (Sweden)

    Cekova Blagica

    2006-01-01

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

  4. Computer simulations of adsorbed liquid crystal films

    Science.gov (United States)

    Wall, Greg D.; Cleaver, Douglas J.

    2003-01-01

    The structures adopted by adsorbed thin films of Gay-Berne particles in the presence of a coexisting vapour phase are investigated by molecular dynamics simulation. The films are adsorbed at a flat substrate which favours planar anchoring, whereas the nematic-vapour interface favours normal alignment. On cooling, a system with a high molecule-substrate interaction strength exhibits substrate-induced planar orientational ordering and considerable stratification is observed in the density profiles. In contrast, a system with weak molecule-substrate coupling adopts a director orientation orthogonal to the substrate plane, owing to the increased influence of the nematic-vapour interface. There are significant differences between the structures adopted at the two interfaces, in contrast with the predictions of density functional treatments of such systems.

  5. Removal of micropollutants from water by nanocomposite membrane adsorbers

    OpenAIRE

    Niedergall, K.; Bach, M.; Hirth, T.; Tovar, G.E.M.; Schiestel, T.

    2014-01-01

    Nanoscaled spheric polymer adsorbers with a variety of chemical surface functionalities were synthesized by miniemulsion polymerization and inverse miniemulsion polymerization. The nanospheres were embedded in polyethersulfone (PES) matrices by a wet-phase inversion process to form nanocomposite membrane adsorbers. The resulting membrane adsorbers were characterized by scanning electron microscopy (SEM), pore size measurements, water flux measurements and various adsorption experiments. The m...

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

    NARCIS (Netherlands)

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

    2002-01-01

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

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2015-09-30

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

  8. Behavior of macromolecules in adsorbed layers

    Institute of Scientific and Technical Information of China (English)

    牟伯中[1; 姚恒申[2; 罗平亚[3

    2000-01-01

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

  9. Green Adsorbents for Wastewaters: A Critical Review

    Directory of Open Access Journals (Sweden)

    George Z. Kyzas

    2014-01-01

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

  10. Orbital tomography for highly symmetric adsorbate systems

    Science.gov (United States)

    Stadtmüller, B.; Willenbockel, M.; Reinisch, E. M.; Ules, T.; Bocquet, F. C.; Soubatch, S.; Puschnig, P.; Koller, G.; Ramsey, M. G.; Tautz, F. S.; Kumpf, C.

    2012-10-01

    Orbital tomography is a new and very powerful tool to analyze the angular distribution of a photoemission spectroscopy experiment. It was successfully used for organic adsorbate systems to identify (and consequently deconvolute) the contributions of specific molecular orbitals to the photoemission data. The technique was so far limited to surfaces with low symmetry like fcc(110) oriented surfaces, owing to the small number of rotational domains that occur on such surfaces. In this letter we overcome this limitation and present an orbital tomography study of a 3,4,9,10-perylene-tetra-carboxylic-dianhydride (PTCDA) monolayer film adsorbed on Ag(111). Although this system exhibits twelve differently oriented molecules, the angular resolved photoemission data still allow a meaningful analysis of the different local density of states and reveal different electronic structures for symmetrically inequivalent molecules. We also discuss the precision of the orbital tomography technique in terms of counting statistics and linear regression fitting algorithm. Our results demonstrate that orbital tomography is not limited to low-symmetry surfaces, a finding which makes a broad field of complex adsorbate systems accessible to this powerful technique.

  11. Effective Thermal Conductivity of Adsorbent Packed Beds

    Science.gov (United States)

    Mori, Hideo; Hamamoto, Yoshinori; Yoshida, Suguru

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

  12. NOx Removal and Effect of Adsorbate-Adsorbate Interactions

    DEFF Research Database (Denmark)

    Khan, Tuhin Suvra

    low-index metal surfaces. Furthermore, I have used DFT calculated adsorption and transition state energies coupled with a microkinetic model to study two industrially important catalytic reactions, NH3 oxidation and selective catalytic reduction of NOx, to obtain the catalytic trends and understand...... these challenges systematically and have developed some new methods and models to counter those challenges and obtain some general understanding of the catalytic process. I have developed an adsorbate-adsorbate interaction model to include the coverage dependency of the adsorption energy in kinetic models...

  13. Adsorption equilibria and kinetics for phenol and cresol onto polymeric adsorbents: Effects of adsorbents/adsorbates structure and interface

    International Nuclear Information System (INIS)

    Phenol and cresol (o-, m-, and p-) were selected as the adsorbates with different dipole moment (cresol > phenol, methyl being electron-drawing group) and solubility (phenol > cresol, methyl being hydrophobic group). Macropore polymers (NDA-1800 and XAD-4), hypercrosslinked polymers (NDA-100), and chemically modified adsorbents (NDA-150 and NDA-99), were comparatively used to investigate the adsorption properties including equilibria, thermodynamics and kinetics. First, all of the results about equilibria show that the adsorption data fit well to the Freundlich model. The adsorption capacity of NDA-99 and NDA-150 especially for phenol is larger in a certain extent than other three types of polymers. The hydrophobic interaction from large specific surface was mainly occurred, while the polar groups containing oxygen and amine markedly enhance the adsorption process via hydrogen interaction. Furthermore, the adsorption amount for NDA-99 and XAD-4 decrease linearly with the solubility of solutes tested. Then, the negative values of enthalpy demonstrate the predominantly exothermic and physical solid-extraction processes. Finally, the relatively more rapid adsorption process could be found onto NDA-150 than NDA-99, with the reason of the double larger pore size of the former. In conclusion, solubility of solute, together with surface area, pore size and modified groups, extremely exerts influences to the adsorption performances

  14. MOLECULAR IMPRINTED POLYMERS—Novel Polymer Adsorbents

    Institute of Scientific and Technical Information of China (English)

    LIHaitao; XUMancai; 等

    2001-01-01

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

  15. Optimizing heterosurface adsorbent synthesis for liquid chromatography

    Science.gov (United States)

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

    2016-03-01

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

  16. Dye sequestration using agricultural wastes as adsorbents

    Directory of Open Access Journals (Sweden)

    Kayode Adesina Adegoke

    2015-12-01

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

  17. The persistence length of adsorbed dendronized polymers.

    Science.gov (United States)

    Grebikova, Lucie; Kozhuharov, Svilen; Maroni, Plinio; Mikhaylov, Andrey; Dietler, Giovanni; Schlüter, A Dieter; Ullner, Magnus; Borkovec, Michal

    2016-07-21

    The persistence length of cationic dendronized polymers adsorbed onto oppositely charged substrates was studied by atomic force microscopy (AFM) and quantitative image analysis. One can find that a decrease in the ionic strength leads to an increase of the persistence length, but the nature of the substrate and of the generation of the side dendrons influence the persistence length substantially. The strongest effects as the ionic strength is being changed are observed for the fourth generation polymer adsorbed on mica, which is a hydrophilic and highly charged substrate. However, the observed dependence on the ionic strength is much weaker than the one predicted by the Odijk, Skolnik, and Fixman (OSF) theory for semi-flexible chains. Low-generation polymers show a variation with the ionic strength that resembles the one observed for simple and flexible polyelectrolytes in solution. For high-generation polymers, this dependence is weaker. Similar dependencies are found for silica and gold substrates. The observed behavior is probably caused by different extents of screening of the charged groups, which is modified by the polymer generation, and to a lesser extent, the nature of the substrate. For highly ordered pyrolytic graphite (HOPG), which is a hydrophobic and weakly charged substrate, the electrostatic contribution to the persistence length is much smaller. In the latter case, we suspect that specific interactions between the polymer and the substrate also play an important role. PMID:27353115

  18. Investigation of drug-porous adsorbent interactions in drug mixtures with selected porous adsorbents.

    Science.gov (United States)

    Madieh, Shadi; Simone, Michael; Wilson, Wendy; Mehra, Dev; Augsburger, Larry

    2007-04-01

    The adsorption of drugs onto porous substrates may prove to be a convenient method by which to enhance the dissolution rate of certain poorly water-soluble drugs in body fluids. The purpose of this research is to provide a better understanding of the type of interactions occurring between drugs and certain pharmaceutically acceptable porous adsorbents that leads to enhanced drug dissolution rates. The interactions between ibuprofen (acidic drug), acetaminophen (acidic drug), dipyridamole (basic drug), and the porous adsorbents used (calcium silicate and silica gel) were investigated using differential scanning calorimetry (DSC), powder X-ray diffraction (PXRD), and Fourier Transform infrared spectroscopy (FTIR). DSC and PXRD results indicated a significant loss of crystallinity of both ibuprofen and acetaminophen but not dipyridamole. In the case of ibuprofen, FTIR results indicated the ionization of the carboxylic group based on the shift in the FTIR carboxylic band. Dissolution of ibuprofen from its mixtures with porous adsorbents was found to be significantly higher compared to the neat drug, whereas dipyridamole dissolution from its mixtures with porous adsorbents was not significantly different from that of the neat drug. PMID:17221849

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

    Science.gov (United States)

    Tovbin, Yu. K.

    2016-08-01

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

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

    DEFF Research Database (Denmark)

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

    2010-01-01

    The adsorption of 2,6-naphthalenedicarboxylic acid (NDCA) molecules on the Ag(110), Cu(110), and Ag(111) surfaces at room temperature has been studied by means of scanning tunnelling microscopy (STM). Further supporting results were obtained using X-ray photoelectron spectroscopy (XPS) and soft X......-ray absorption spectroscopy (XAS). On the Ag(110) support, which had an average terrace width of only 15 nm, the NDCA molecules form extended one-dimensional (1-D) assemblies, which are oriented perpendicular to the step edges and have lengths of several hundred nanometres. This shows that the assemblies have a......-edge crossing is not observed when the molecules are adsorbed on the isotropic Ag(111) or more reactive Cu(110) surfaces. On Ag(111), similar 1-D assemblies are formed to those on Ag(110), but they are oriented along the step edges. On Cu(110), the carboxylic groups of NDCA are deprotonated and form covalent...

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2015-09-30

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

  2. Optimizing Conditions to Cholesterol Adsorbed with Carboxymethyl Chitosan

    OpenAIRE

    Mardiyah Kurniasih; Dwi Kartika; Riyanti Riyanti

    2016-01-01

    A research on optimizing conditions to cholesterol adsorbed have been performed. Optimization was performed by varying: contact time, adsorbent weight and temperature of the system's. A full factorial experimental design was used in this study. Characterization performed on the synthesized chitosan and carboxymethyl chitosan including FTIR, water content, ash content, solubility, porosity, and swelling effect. The results showed that carboxymethyl chitosan able to adsorb cholesterol under con...

  3. DESORPTION OF VOCs FROM POLYMERIC ADSORBENTS UNDER MICROWAVE FIELD

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

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

  4. 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.

  5. Trends in adsorbate induced core level shifts

    Science.gov (United States)

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

    2015-10-01

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

  6. Linear transport models for adsorbing solutes

    Science.gov (United States)

    Roth, K.; Jury, W. A.

    1993-04-01

    A unified linear theory for the transport of adsorbing solutes through soils is presented and applied to analyze movement of napropamide through undisturbed soil columns. The transport characteristics of the soil are expressed in terms of the travel time distribution of the mobile phase which is then used to incorporate local interaction processes. This approach permits the analysis of all linear transport processes, not only the small subset for which a differential description is known. From a practical point of view, it allows the direct use of measured concentrations or fluxes of conservative solutes to characterize the mobile phase without first subjecting them to any model. For complicated flow regimes, this may vastly improve the identification of models and estimation of their parameters for the local adsorption processes.

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

    DEFF Research Database (Denmark)

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

    2010-01-01

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

  8. Thermodynamic study of fatty acids adsorption on different adsorbents

    International Nuclear Information System (INIS)

    This work has as objective the study about the adsorption behavior of fatty acids (acetic, propionic, and butyric) on activated carbon and on modified and unmodified montmorillonite clays as a function of temperature and initial concentration of the adsorbate, through adsorption isotherms and their thermodynamic parameters (ΔG, ΔH, and ΔS). The activated carbon presented a higher adsorption capacity due to its relatively large surface area, compared to others adsorbents. The polar characteristic of fatty acids decreased with the increase in the length of non-polar hydrocarbon chain, improving the affinity between the activated carbon (non-polar adsorbent) and the acids. The adsorption capacity of modified montmorillonite (polar adsorbent) was favored due to the presence of the organic cation among its layers, which make the surface more hydrophobic and organophilic when compared to the unmodified montmorillonite surface. The amount of fatty acids adsorbed in the adsorbents surface increased with the concentration, at constant temperature, and decreased with the increase of temperature, at constant concentration. The amount of fatty acids adsorbed in the three adsorbents was related to the surface area and polarity of the adsorbent, concentration and solubility of the adsorbate and temperature of the solution. The negative values of ΔG and ΔH showed that the adsorption on activated carbon and on modified and unmodified montmorillonite clays was a spontaneous and an exothermic process. The decrease in the values of ΔG, with the increase of temperature, demonstrated that the adsorption was benefited by the high temperature and the positive values of ΔS showed that the fatty acids molecules were in a more randomic condition in the adsorbed state than in solution. The experimental results obtained at the temperatures of (298, 303, 313, and 323) K showed that experimental data were well represented by the Langmuir and Freundlich isotherms models

  9. Single bank NOx adsorber for heavy duty diesel engines

    NARCIS (Netherlands)

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

    2003-01-01

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

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

    Institute of Scientific and Technical Information of China (English)

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

    2009-01-01

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

  11. Structure and properties of water film adsorbed on mica surfaces

    Science.gov (United States)

    Zhao, Gutian; Tan, Qiyan; Xiang, Li; Cai, Di; Zeng, Hongbo; Yi, Hong; Ni, Zhonghua; Chen, Yunfei

    2015-09-01

    The structure profiles and physical properties of the adsorbed water film on a mica surface under conditions with different degrees of relative humidity are investigated by a surface force apparatus. The first layer of the adsorbed water film shows ice-like properties, including a lattice constant similar with ice crystal, a high bearing capacity that can support normal pressure as high as 4 MPa, a creep behavior under the action of even a small normal load, and a character of hydrogen bond. Adjacent to the first layer of the adsorbed water film, the water molecules in the outer layer are liquid-like that can flow freely under the action of external loads. Experimental results demonstrate that the adsorbed water layer makes the mica surface change from hydrophilic to weak hydrophobic. The weak hydrophobic surface may induce the latter adsorbed water molecules to form water islands on a mica sheet.

  12. Adsorption of Fluoride Ion by Inorganic Cerium Based Adsorbent

    Institute of Scientific and Technical Information of China (English)

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

    2004-01-01

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

  13. Structure and properties of water film adsorbed on mica surfaces.

    Science.gov (United States)

    Zhao, Gutian; Tan, Qiyan; Xiang, Li; Cai, Di; Zeng, Hongbo; Yi, Hong; Ni, Zhonghua; Chen, Yunfei

    2015-09-14

    The structure profiles and physical properties of the adsorbed water film on a mica surface under conditions with different degrees of relative humidity are investigated by a surface force apparatus. The first layer of the adsorbed water film shows ice-like properties, including a lattice constant similar with ice crystal, a high bearing capacity that can support normal pressure as high as 4 MPa, a creep behavior under the action of even a small normal load, and a character of hydrogen bond. Adjacent to the first layer of the adsorbed water film, the water molecules in the outer layer are liquid-like that can flow freely under the action of external loads. Experimental results demonstrate that the adsorbed water layer makes the mica surface change from hydrophilic to weak hydrophobic. The weak hydrophobic surface may induce the latter adsorbed water molecules to form water islands on a mica sheet.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2014-08-01

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

  15. Modification of the sulphur resistance of platinum by addition of metals for aromatics hydrogenation; Modification de la thioresistance du platine par ajouts d'elements metalliques pour l'hydrogenation d'aromatiques

    Energy Technology Data Exchange (ETDEWEB)

    Guillon, E.

    1999-09-15

    The aim of this study is based on the understanding of sulphur resistance of platinum catalytic systems. In this work, bimetallic systems (Pt-Ge, Pt-Au and Pt-Pd) supported on {gamma}-alumina have been studied. Preparation methods have been chosen to give the best control of the physicochemical properties of final system. Electronic and geometrical properties of the metallic phase were characterised by various techniques (TPR, infrared spectroscopy of adsorbed CO (IR(CO)), EXAFS, LEIS). Ortho-xylene hydrogenation in presence of 100 ppm of sulphur was used as model catalytic test in order to study the sulphur resistance of the catalysts. It has been shown that germanium and palladium act as electro-acceptors toward platinum. The ranking of catalytic activity in presence of sulphur is as followed: Pt-Pd > Pt-Au {approx_equal} Pt >> Pt-Ge {approx_equal} 0. The best sulphur resistance for Pt-Pd was obtained for the composition Pt{sub 20}Pd{sub 80} (Pd/Pt=4). An eggshell PdS structure with Pt (sulfur free) core is proposed. These works show that the sulphur resistance of platinum is not only linked with its electronic properties. They allow us to propose an original concept of sulphur resistant catalyst taking into account each catalytic parameters such as chemical bonding of S and aromatic compounds on the metallic site, physico-chemical characteristics of the bimetallic aggregates (particle size, structure, surface composition) and electronic modification of surface atoms in bimetallic catalysts. (author)

  16. Mercury adsorption properties of sulfur-impregnated adsorbents

    Science.gov (United States)

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

    2002-01-01

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

  17. Methane Recovery from Gaseous Mixtures Using Carbonaceous Adsorbents

    Science.gov (United States)

    Buczek, Bronisław

    2016-06-01

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

  18. ADSORPTION OF PHENYLACETIC ACID ON MACROPOROUS POLYMERIC ADSORBENTS

    Institute of Scientific and Technical Information of China (English)

    PANBingcai; CHENJinlong; 等

    2002-01-01

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

  19. ADSORPTION OF PHENYLACETIC ACID ON MACROPOROUS POLYMERIC ADSORBENTS

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

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

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

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

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

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

    KAUST Repository

    Bollini, Praveen

    2012-11-21

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

  2. Radiation grafted adsorbents for newly emerging environmental applications

    Science.gov (United States)

    Mahmoud Nasef, Mohamed; Ting, T. M.; Abbasi, Ali; Layeghi-moghaddam, Alireza; Sara Alinezhad, S.; Hashim, Kamaruddin

    2016-01-01

    Radiation induced grafting (RIG) is acquired to prepare a number of adsorbents for newly emerging environmental applications using a single route involving RIG of glycidymethacrylate (GMA) onto polyethylene-polypropylene (PE-PP) non-woven fabric. The grafted fabric was subjected to one of three functionalization reactions to impart desired ionic characters. This included treatment with (1) N-dimethyl-D-glucamine, (2) triethylamine and (3) triethylamine and alkalisation with KOH. Fourier transform infrared spectroscopy (FTIR) and scanning electron microscope (SEM) were used to study the changes in chemical and physical structures of the obtained fibrous adsorbents. The potential applications of the three adsorbents for removal of boron from solutions, capturing CO2 from CO2/N2 mixtures and catalysing transesterification of triacetin/methanol to methyl acetate (biodiesel) were explored. The obtained fibrous adsorbents provide potential alternatives to granular resins for the investigated applications and require further development.

  3. A NOVEL METAL CHELATE AFFINITY ADSORBENT FOR PROTEIN UPTAKE

    Institute of Scientific and Technical Information of China (English)

    WANGYongjian; BAIShu; 等

    2001-01-01

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

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

    Directory of Open Access Journals (Sweden)

    M. R. Mafra

    2013-09-01

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

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

    Directory of Open Access Journals (Sweden)

    RAISA NASTAS

    2012-03-01

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

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

    Data.gov (United States)

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

  7. Sol-Gel Synthesized Adsorbents for Metal Separation

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

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

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

    Energy Technology Data Exchange (ETDEWEB)

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

    1997-04-01

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

  9. Development of novel adsorbents for environmental cleaning by radiation

    International Nuclear Information System (INIS)

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

  10. Development of solid adsorbent materials for CO₂capture

    OpenAIRE

    Ogbuka, Chidi Premie

    2013-01-01

    The application of solid adsorbents for gas separation in pre-combustion carbon capture from gasification processes has gained attention in recent times. This is due to the potential of the technology to reduce the overall energy penalty associated with the capture process. However, this requires the development of solid adsorbent materials with large selectivity, large adsorption capacity, fast adsorption kinetics for CO2 coupled with good mechanical strength and thermal stability. In this ...

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

    OpenAIRE

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

    2015-01-01

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

  12. Electronic and electrochemical doping of graphene by surface adsorbates

    OpenAIRE

    Hugo Pinto; Alexander Markevich

    2014-01-01

    Many potential applications of graphene require its precise and controllable doping with charge carriers. Being a two-dimensional material graphene is extremely sensitive to surface adsorbates, so its electronic properties can be effectively modified by deposition of different atoms and molecules. In this paper, we review two mechanisms of graphene doping by surface adsorbates, namely electronic and electrochemical doping. Although, electronic doping has been extensively studied and discussed...

  13. THE USE OF LOW COST ADSORBENTS FOR PURIFICATION WASTEWATER

    OpenAIRE

    Višekruna, Antonija; Štrkalj, Anita; Marinić Pajc, Ljiljana

    2011-01-01

    Adsorption is one of the effective methods of advanced wastewater treatment, which industries employ to reduce hazardous organic and inorganic wastes in effluents. The use of low cost adsorbent has been investigated as a replacement for current costly methods of removing toxic substances from wastewater. In this article, the use of low cost adsorbents for the removal of toxic substances from wastewater has been reviewed.

  14. Residence time determination for adsorbent beds of different configurations

    Energy Technology Data Exchange (ETDEWEB)

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

    1995-02-01

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

  15. Efforts to Consolidate Chalcogels with Adsorbed Iodine

    Energy Technology Data Exchange (ETDEWEB)

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

    2013-08-28

    This document discusses ongoing work with non-oxide aerogels, called chalcogels, that are under development at the Pacific Northwest National Laboratory as sorbents for gaseous iodine. Work was conducted in fiscal year 2012 to demonstrate the feasibility of converting Sn2S3 chalcogel without iodine into a glass. This current document summarizes the work conducted in fiscal year 2013 to assess the consolidation potential of non-oxide aerogels with adsorbed iodine. The Sn2S3 and Sb13.5Sn5S20 chalcogels were selected for study. The first step in the process for these experiments was to load them with iodine (I2). The I2 uptake was ~68 mass% for Sn2S3 and ~50 mass% for Sb13.5Sn5S20 chalcogels. X-ray diffraction (XRD) of both sets of sorbents showed that metal-iodide complexes were formed during adsorption, i.e., SnI4 for Sn2S3 and SbI3 for Sb13.5Sn5S20. Additionally, metal-sulfide-iodide complexes were formed, i.e., SnSI for Sn2S3 and SbSI for Sb13.5Sn5S20. No XRD evidence for unreacted iodine was found in any of these samples. Once the chalcogels had reached maximum adsorption, the consolidation potential was assessed. Here, the sorbents were heated for consolidation in vacuum-sealed quartz vessels. The Sb13.5Sn5S20 chalcogel was heated both (1) in a glassy carbon crucible within a fused quartz tube and (2) in a single-containment fused quartz tube. The Sn2S3 chalcogel was only heated in a single-containment fused quartz tube. In both cases with the single-containment fused quartz experiments, the material consolidated nicely. However, in both cases, there were small fractions of metal iodides not incorporated into the final product as well as fused quartz particles within the melt due to the sample attacking the quartz wall during the heat treatment. The Sb13.5Sn5S20 did not appear to attack the glassy carbon crucible so, for future experiments, it would be ideal to apply a coating, such as pyrolytic graphite, to the inner walls of the fused quartz vessel to prevent

  16. Evaluation of a cesium adsorbent grafted with ammonium 12-molybdophosphate

    Science.gov (United States)

    Shibata, Takuya; Seko, Noriaki; Amada, Haruyo; Kasai, Noboru; Saiki, Seiichi; Hoshina, Hiroyuki; Ueki, Yuji

    2016-02-01

    A fibrous cesium (Cs) adsorbent was developed using radiation-induced graft polymerization with a cross-linked structure containing a highly stable adsorption ligand. The ligand, ammonium 12-molybdophosphate (AMP), was successfully introduced onto the fibrous polyethylene trunk material. The resulting Cs adsorbent contained 36% nonwoven fabric polyethylene (NFPE), 1% AMP, 2% triallyl isocyanurate (TAIC) and 61% glycidyl methacrylate (GMA). The adsorbent's Cs adsorption capacity was evaluated using batch and column tests. It was determined that the adsorbent could be used in a wide pH range. The amount of desorbed molybdenum, which can be used as an estimate for AMP stability on the Cs adsorbent, was minimized at the standard drinking water pH range of 5.8-8.6. Based from the inspection on the adherence of these results to the requirements set forth by the Food Sanitation Act by a third party organization, it can be concluded that the developed Cs adsorbent can be safely utilized for drinking water.

  17. Optimizing Conditions to Cholesterol Adsorbed with Carboxymethyl Chitosan

    Directory of Open Access Journals (Sweden)

    Mardiyah Kurniasih

    2016-05-01

    Full Text Available A research on optimizing conditions to cholesterol adsorbed have been performed. Optimization was performed by varying: contact time, adsorbent weight and temperature of the system's. A full factorial experimental design was used in this study. Characterization performed on the synthesized chitosan and carboxymethyl chitosan including FTIR, water content, ash content, solubility, porosity, and swelling effect. The results showed that carboxymethyl chitosan able to adsorb cholesterol under conditions optimal adsorbent with cholesterol ratio (1:200 with a contact time of 90 minutes at temperature of 40 °C. Meanwhile, at a temperature of 55 °C carboxymethyl chitosan capable of adsorb cholesterol under conditions optimal adsorbent with cholesterol ratio (1:300 with a contact time of 30 minutes. Chitosan and carboxymethyl chitosan synthesized has a water content of 7.4 and 10.2%, ash content of 0.14 and 2.29%, solubility in distilled water at 1.10-5and 1.98.10-3%, solubility in acetic acid 0.02 and 0.04%, porosity at 88.3% and 88.8%, and swelling at 163.13 and 182.98%.

  18. Cryogenic adsorber design in a helium refrigeration system

    Science.gov (United States)

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

    2012-06-01

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

  19. Activity of lactoperoxidase when adsorbed on protein layers.

    Science.gov (United States)

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

    2008-09-15

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

  20. Gold recovery from low concentrations using nanoporous silica adsorbent

    Science.gov (United States)

    Aledresse, Adil

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

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

    Science.gov (United States)

    Oyola, Yatsandra; Vukovic, Sinisa; Dai, Sheng

    2016-05-28

    Amidoxime-based polymer adsorbents have attracted interest within the last decade due to their high adsorption capacities for uranium and other rare earth metals from seawater. The ocean contains an approximated 4-5 billion tons of uranium and even though amidoxime-based adsorbents have demonstrated the highest uranium adsorption capacities to date, they are still economically impractical because of their limited recyclability. Typically, the adsorbed metals are eluted with a dilute acid solution that not only damages the amidoxime groups (metal adsorption sites), but is also not strong enough to remove the strongly bound vanadium, which decreases the adsorption capacity with each cycle. We resolved this challenge by incorporating Le Chatelier's principle to recycle adsorbents indefinitely. We used a solution with a high concentration of amidoxime-like chelating agents, such as hydroxylamine, to desorb nearly a 100% of adsorbed metals, including vanadium, without damaging the metal adsorption sites and preserving the high adsorption capacity. The method takes advantage of knowing the binding mode between the amidoxime ligand and the metal and mimics it with chelating agents that then in a Le Chatelier's manner removes metals by shifting to a new chemical equilibrium. For this reason the method is applicable to any ligand-metal adsorbent and it will make an impact on other extraction technologies. PMID:27117598

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

    International Nuclear Information System (INIS)

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

  3. Quantification des sources de polluants dans un bassin versant séparatif à Nantes : des retombées atmosphériques jusqu'au réseau d'assainissement

    OpenAIRE

    LAMPREA, Diana Katerine; Ruban, Véronique; Deneele, Dimitri

    2009-01-01

    Des polluants tels que les éléments traces métalliques, les hydrocarbures aromatiques polycycliques (HAP) et les pesticides (glyphosate, AMPA et diuron) on été mesurés dans les retombées atmosphériques, les eaux de ruissellement de toiture et les eaux de ruissellement transportées à l'exutoire d'un bassin versant drainé par un réseau d'assainissement séparatif. Les résultats de cette étude ont montré que les matières en suspension, les métaux (zinc, cuivre et plomb) et le glyphosate sont les ...

  4. Characterization of atmospheric deposition and runoff water on a small suburban catchment

    OpenAIRE

    LAMPREA, K; Ruban, Véronique

    2010-01-01

    Une étude a été menée dans le cadre de l'IRSTV (Institut de Recherche en Sciences et Techniques de la Ville) afin de caractériser les retombées atmosphériques et les eaux de ruissellement d'un petit bassin versant séparatif périurbain (31 ha) à Nantes. Les métaux traces, les hydrocarbures aromatiques polycycliques (HAP) et les pesticides ont été mesurés. La caractérisation des retombées atmosphériques montre une grande variabilité des concentrations en métaux, sans lien avec les caractéris...

  5. Adsorption of rare earths with crown ether adsorbents

    International Nuclear Information System (INIS)

    Crown ether - phosphotungstic acid (PW) and crown ether -phosphomolybdic acid (PMo) precipitates, and also the granular entrapped crown ether - PMo (or PW) in polyacrylamide, were prepared and applied as adsorbents for rare earth metal ions. Adsorbents containing 15-crown-5, such as 15-crown-5 - PMo, were better adsorbents than the other crown ether precipitates. The adsorption capacity of 15-crown-5 - PMo for Eu3+ was determined and corresponded to about 0.166 mmol of Eu3+ per gram of the absorbent. The effects of pH and metal ion concentration on adsorption were also investigated. Crown ether - PMo (or PW) precipitates underwent hydrolysis at pH >= 1, but the granular entrapped crown ether - PMo (or PW) - polyacrylamide adsorbents were not hydrolysed at pH >= 1. The adsorption of individual rare earth ions with 15-crown-5 - PMo - polyacrylamide showed that Tb3+, Nd3+, Eu3+ and Gd3+ were readily adsorbed, but adsorption was difficult for Ce4+, Sm3+ and Dy3+. (author)

  6. [DSC and FTIR study of adsorbed lysozyme on hydrophobic surface].

    Science.gov (United States)

    Lei, Zu-meng; Geng, Xin-peng; Dai, Li; Geng, Xin-du

    2008-09-01

    During a process of hen egg white lysozyme adsorption and folding on a moderately hydrophobic surface (PEG-600), the effects of salt((NH4)2SO4) concentrations, surface coverage and denaturant (guanidine hydrochloride, GuHCl) concentrations on thermal stability and the changes in the molecular conformation of adsorbed native and denatured lysozyme without aqueous solution were studied with a combination of differential scanning calorimetry (DSC) with FTIR spectroscopy. The results showed that temperature due to endothermic peaks was reduced and the disturbance increased at higher temperature with the increase in salt concentration and surface coverage of adsorbed protein. beta-Sheet and beta-Turn stucture increased while alpha-Helix structure decreased after the adsorption. The peaks corresponding to both C-C stretching frequency in 1400-1425 cm(-1) and amide I band frequency in 1650-1670 cm(-1) of adsorbed denatured lysozyme can be detected in FTIR spectra while that due to amide I band frequency of adsorbed native lysozyme almost can't be observed. Adsorption resulted in structural loss of adsorbed native lysozyme, whose performance was less stable. PMID:19093560

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

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

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

  8. ADSORPTION OF DINITROPHENOLS ONTO POLYMERIC ADSORBENTS AND ITS MECHANISM

    Institute of Scientific and Technical Information of China (English)

    SHIZuoqing; XUMancai; 等

    2000-01-01

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

  9. Metal loaded zeolite adsorbents for hydrogen cyanide removal

    Institute of Scientific and Technical Information of China (English)

    Ping Ning; Juan Qiu; Xueqian Wang; Wei Liu; Wei Chen

    2013-01-01

    Metal (Cu,Co,or Zn) loaded ZSM-5 and Y zeolite adsorbents were prepared for the adsorption of hydrogen cyanide (HCN) toxic gas.The results showed that the HCN breakthrough capacity was enhanced significantly when zeolites were loaded with Cu.The physical and chemical properties of the adsorbents that influence the HCN adsorption capacity were analyzed.The maximal HCN breakthrough capacities were about the same for both zeolites at 2.2 mol of HCN/mol of Cu.The Cu2p XPS spectra showed that the possible species present were Cu2O and CuO.The N1s XPS data and FT-IR spectra indicated that CN-would be formed in the presence of Cu+/Cu2+and oxygen gas,and the reaction product could be adsorbed onto Cu/ZSM-5 zeolite more easily than HCN.

  10. Lotus Dust Mitigation Coating and Molecular Adsorber Coating

    Science.gov (United States)

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

    2015-01-01

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

  11. Emanation-thermal analysis of basalt fiber adsorbents

    International Nuclear Information System (INIS)

    Complex emanation-thermal analysis is used for investigating structural changes in basalt adsorbents taking place during thermal affects on material. Adsorbent is prepared by two-stage treatment of staple basalt fibers by hydrochloric acid. Isotherms of sorption of liquid nitrogen vapors by new sorbents are measured. Areas of the open surface, porosity and pores size spectra of leached fibers are calculated. It is determined by the method of thermostimulated gassing that adsorbed water is in two energetically different states in porous basalt fiber: basic part of water vapors is desorbed at 90-110 Deg C, remained part -at 300-320 Deg C. Full regeneration of sorbent requires warming up to 550 Deg C

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

    Directory of Open Access Journals (Sweden)

    Andrius Agintas

    2011-04-01

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

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

    Institute of Scientific and Technical Information of China (English)

    Yuqing ZHANG; Yahui ZHANG; Zhen QIN; Zhenrong MA

    2008-01-01

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

  14. Decontamination of radioactive process waste water by adsorbing colloid flotation

    International Nuclear Information System (INIS)

    Adsorbing colloid flotation was tested to remove 144Ce, 60Co, 65Zn, and 89Sr from radioactive process waste water. Potassium oleate was used as the collector, and Fe(III) hydroxide, Al(III) hydroxide or Co(II) hydroxide as the coprecipitant. Under optimal conditions, removals exceeding 99% could be achieved for 65Zn with any of the tested coprecipitants, for 144Ce with Fe(III) and Co(II) hydroxides and for 60Co with only Co(II) hydroxide. For 89Sr removals of 90% could be achieved only with Fe(III) hydroxide. The adsorbing colloid flotation process was compared with both chemical precipitation and ion exchange. Advantages of adsorbing colloid flotation are discussed. (author)

  15. Extracting uranium from seawater: Promising AF series adsorbents

    International Nuclear Information System (INIS)

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

  16. 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

  17. Preparation of thiophilic paramagnetic adsorbent for separation of antibodies

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

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

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

    Science.gov (United States)

    Goldberg, Marvin C.

    1985-01-01

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

  19. Removal of uranium by the adsorbents produced from coffee residues

    International Nuclear Information System (INIS)

    Large amounts of coffee residues contaminate the environment and reprocessing of them as valuable products such as adsorbents will be a good solution from an environmental and economic point of view. In this study some adsorbents were produced from coffee residues and used for batch removal experiments of uranium from aqueous solutions. The adsorption kinetics was found to follow the Lagergren equation. The adsorption process was described with the Langmuir and Freundlich isotherms. Additionally, the effect of different cations on the adsorption of uranium was studied. (author)

  20. Photoinduced Surface Dynamics of CO Adsorbed on a Platinum Electrode

    OpenAIRE

    Noguchi, Hidenori; Okada, Tsubasa; Uosaki, Kohei

    2006-01-01

    The surface dynamics of adsorbed CO molecules formed by dissociative adsorption of HCHO at a polycrystalline Pt electrode/electrolyte solution interface was studied by picosecond time-resolved sum-frequency generation (TR-SFG) spectroscopy. A SFG peak at 2050-2060 cm^[-1] was observed at the Pt electrode in HClO4 solution containing HCHO at 0-300 mV (vs Ag/AgCl), indicating the formation of adsorbed CO at an atop site of the Pt surface as a result of dissociative adsorption of HCHO. The peak ...

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

    Science.gov (United States)

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

    2016-05-01

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

  2. Adsorption of iodine by silver-impregnated hydrophobic adsorbent

    International Nuclear Information System (INIS)

    Hydrophobic adsorbents, which consist of porous styrene-divinylbenzene copolymer (SDB) impregnated with silver, were developed for the removal of iodine from the dissolver off-gas (DOG). The adsorption of iodine in a simulated off-gas including iodine, NOx and water vapor was examined by use of an adsorption column packed with the hydrophobic adsorbents. Silver impregnation methods using organic solutions were proposed. By use of dioxan and butylamine, which can swell the SDB easily, silver nitrate and metallic silver were uniformly distributed in the SDB particles. The breakthrough of iodine was not influenced by the presence of NOx and water vapor. For a macroporous SDB with the pore volume of 1.59 ml/g-SDB and the average pore diameter of 500A, impregnated with metallic silver at silver content of 28 wt%, a high adsorption capacity of 0.14g-I2/cm3-adsorbent was obtained, compared to that of a commercial adsorbent. AgNO3-impregnated silica gel. The impregnated silver was utilized about 91% for the iodine adsorption. (author)

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

    NARCIS (Netherlands)

    Vliet, van T.

    1977-01-01

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

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

    Directory of Open Access Journals (Sweden)

    Jović-Jovičić Natаša

    2014-01-01

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

  5. EVALUATING VARIOUS ADSORBENTS AND MEMBRANES FOR REMOVING RADIUM FROM GROUNDWATER

    Science.gov (United States)

    Field studies were conducted in Lemont, Ill., to evaluate specific adsorbents and reverse osmosis (RO) membranes for removing radium from groundwater. A radium-selective complexer and barium-sulfate-loaded alumina appeared to have the best potential for low-cost adsorption of ra...

  6. Agricultural By-products as Mercury Adsorbents in Gas Applications

    Science.gov (United States)

    Increased emphasis on reduction of mercury emissions from coal fired electric power plans have resulted in environmental regulations that may in the future require application of activated carbons as mercury sorbents. The sorbents could be injected into the flue gas stream where is adsorbs the merc...

  7. Agricultural Waste as Sources for Mercury Adsorbents in Gas Applications

    Science.gov (United States)

    Increased emphasis on reduction of mercury emissions from coal fired electric power plants have resulted in environmental regulations that may in the future require application of activated carbons as mercury sorbents. The sorbents could be injected into the flue gas stream where it adsorbs the mer...

  8. Extracting uranium from seawater: Promising AI series adsorbents

    International Nuclear Information System (INIS)

    A series of adsorbent (AI10 through AI17) were successfully developed at ORNL by radiation induced graft polymerization (RIGP) of acrylonitrile (AN) and vinylphosphonic acid (VPA) (at different mole/mole ratios) onto high surface area polyethylene fiber, with higher degree of grafting which ranges from 110 300%. The grafted nitrile groups were converted to amidoxime groups by reaction with 10 wt% hydroxylamine at 80 C for 72 hours. The amidoximated adsorbents were then conditioned with 0.44M KOH at 80 C followed by screening at ORNL with simulated seawater spiked with 8 ppm uranium. Uranium adsorption capacity in simulated seawater screening ranged from 171-187 g-U/kg-ads irrespective of %DOG. The performance of the adsorbents for uranium adsorption in natural seawater was also carried out using flow-through-column at Pacific Northwest National Laboratory (PNNL). The three hours KOH conditioning was better for higher uranium uptake than one hour. The adsorbent AI11 containing AN and VPA at the mole ration of 3.52, emerged as the potential candidate for higher uranium adsorption (3.35 g-U/Kg-ads.) after 56 days of exposure in the seawater in the flow-through-column. The rate vanadium adsorption over uranium was linearly increased throughout the 56 days exposure. The total vanadium uptake was ~5 times over uranium after 56 days

  9. Interactions of organic contaminants with mineral-adsorbed surfactants

    Science.gov (United States)

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

    2003-01-01

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

  10. PREPARATION AND ADSORBABILITY OF DEXTRAN MICROSPHERES WITH UNIFORM DIAMETER

    Institute of Scientific and Technical Information of China (English)

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

    2005-01-01

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

  11. HYDROGEN BONDING IN POLYMERIC ADSORBENTS BASED ADSORPTION AND SEPARATION

    Institute of Scientific and Technical Information of China (English)

    XUMancai; SHIZuoqing; 等

    2000-01-01

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

  12. Microporous carbonaceous adsorbents for CO2 separation via selective adsorption

    KAUST Repository

    Zhao, Yunfeng

    2015-01-01

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

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

    Directory of Open Access Journals (Sweden)

    Reinaque AP

    2012-08-01

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

  14. Effect of adsorbent addition on floc formation and clarification.

    Science.gov (United States)

    Younker, Jessica M; Walsh, Margaret E

    2016-07-01

    Adding adsorbent into the coagulation process is an emerging treatment solution for targeting hard-to-remove dissolved organic compounds from both drinking water and industrial wastewater. The impact of adding powdered activated carbon (PAC) or organoclay (OC) adsorbents with ferric chloride (FeCl3) coagulant was investigated in terms of potential changes to the coagulated flocs formed with respect to size, structure, and breakage and regrowth properties. The ability of dissolved air flotation (DAF) and sedimentation (SED) clarification processes to remove hybrid adsorbent-coagulant flocs was also evaluated through clarified water quality analysis of samples collected in bench-scale jar test experiments. The jar tests were conducted using both a synthetic fresh water and oily wastewater test water spiked with dissolved aromatic compounds phenol and naphthalene. Results of the study demonstrated that addition of adsorbent reduced the median coagulated floc size by up to 50% but did not affect floc strength or regrowth potential after application of high shear. Experimental results in fresh water demonstrated that sedimentation was more effective than DAF for clarification of both FeCl3-PAC and FeCl3-OC floc aggregates. However, experimental tests performed on the synthetic oily wastewater showed that coagulant-adsorbent floc aggregates were effectively removed with both DAF and sedimentation treatment, with lower residual turbidity achieved in clarified water samples than with coagulation treatment alone. Addition of OC or PAC into the coagulation process resulted in removals of over half, or nearly all of the dissolved aromatics, respectively. PMID:27064206

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

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

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

  16. Novel adsorbent applicability for decontamination of printing wastewater

    Science.gov (United States)

    Kiurski, Jelena; Oros, Ivana; Ranogajec, Jonjaua; Kecic, Vesna

    2013-04-01

    Adsorption capacity of clayey minerals can be enhanced by replacing the natural exchangeable cations with organic cations, which makes the clay surface more hydrophobic. Different solids such as activated carbon, clay minerals, zeolites, metal oxides and organic polymers have been tested as effective adsorbents. On a global scale, clays have a large applicability for decontamination, purification of urban and industrial residual waters, protection of waste disposal areas, and purification of industrial gases and so on. Clay derivative materials with high adsorption capacities are very attractive from an economical point of view. Due to the economic constraints, a development of cost effective and clean processes is desired. Adsorption processes has proved to be the most effective, especially for effluents with moderate and low heavy metal concentrations, as like as in printing wastewaters. Among several removal technologies, the adsorption of Zn(II) ion onto NZ, B, pure C and C with PEG 600 addition could be of great importance for the printing wastewaters purification. However, the newly designed adsorbent of the defined pore size distribution and phase structure considered as the most suitable material for Zn(II) ion removal. The values of distribution coefficient (Kd) increased with decreasing of the adsorbent amount. The Kd values depend also on the type of used adsorbent, the following increased order is obtained: NZ Langmuir > DKR. The study also showed that the fired clay modified with PEG 600 addition has great potential (up to 93.5%) to remove Zn(II) ion from printing wastewaters. The results showed that fired clay, fired clay modified with polymer addition, natural zeolite and bentonite can be used for Zn(II) ion removal from printing wastewaters by adsorption method in laboratory batch mode. Based on higher affinity to the Zn(II) ion adsorption than fired clay, bentonite and zeolite it was concluded that feasibility of newly designed clayey adsorbent

  17. Nanofiber adsorbents for high productivity continuous downstream processing.

    Science.gov (United States)

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

    2015-11-10

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

  18. The cultivation of of medicinal and aromatique plants in Romania

    Directory of Open Access Journals (Sweden)

    Leon Sorin MUNTEAN

    1985-08-01

    Full Text Available Scientific research regarding medicinal plants started first in Cluj, where the Research Station for Medicinal Plants was first organized in Europe (1904. Research in this field was continued after 1930 by the staff of the Agronomy Researh Institute of Romania (ICAR. Beginning with 1975 the national research programme regarding the medicinal plants is coordinated by the Research Station for Medicinal and Aromatic Plants -SCPMA - Fundulea. Studies are performed in the experimental fields and in the laboratories of this institute and different other research stations and universities in Romania. Beginning with 1979, a new specialized periodical - Herba Romanica - published the main results in the field. At present there are cultivated in Romania about 60 different medicinal and aromatic plant species. Recently a tendency emerged toward the concentration of the production to the most suitable regions and the specialization of different farms for the cultivation of a more restricted number of species. In the second part of the paper the species studied and/or cultivated in the experimental fields of the Agronomy Institute Cluj-Napoca are presented with a chronological list of papers published by the stuff in the period 1975-1984.

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

    Digital Repository Service at National Institute of Oceanography (India)

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

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

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

    Institute of Scientific and Technical Information of China (English)

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

    2001-01-01

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

  1. Removal of acutely hazardous pharmaceuticals from water using multi-template imprinted polymer adsorbent.

    Science.gov (United States)

    Venkatesh, Avinash; Chopra, Nikita; Krupadam, Reddithota J

    2014-05-01

    Molecularly imprinted polymer adsorbent has been prepared to remove a group of recalcitrant and acutely hazardous (p-type) chemicals from water and wastewaters. The polymer adsorbent exhibited twofold higher adsorption capacity than the commercially used polystyrene divinylbenzene resin (XAD) and powdered activated carbon adsorbents. Higher adsorption capacity of the polymer adsorbent was explained on the basis of high specific surface area formed during molecular imprinting process. Freundlich isotherms drawn showed that the adsorption of p-type chemicals onto polymer adsorbent was kinetically faster than the other reference adsorbents. Matrix effect on adsorption of p-type chemicals was minimal, and also polymer adsorbent was amenable to regeneration by washing with water/methanol (3:1, v/v) solution. The polymer adsorbent was unaltered in its adsorption capacity up to 10 cycles of adsorption and desorption, which will be more desirable in cost reduction of treatment compared with single-time-use activated carbon. PMID:24499987

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

    Institute of Scientific and Technical Information of China (English)

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

    2005-01-01

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

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

    Science.gov (United States)

    Santore, Maria; Mubarekyan, Ervin

    2001-03-01

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

  4. Adsorbed molecules in external fields: Effect of confining potential.

    Science.gov (United States)

    Tyagi, Ashish; Silotia, Poonam; Maan, Anjali; Prasad, Vinod

    2016-12-01

    We study the rotational excitation of a molecule adsorbed on a surface. As is well known the interaction potential between the surface and the molecule can be modeled in number of ways, depending on the molecular structure and the geometry under which the molecule is being adsorbed by the surface. We explore the effect of change of confining potential on the excitation, which is largely controlled by the static electric fields and continuous wave laser fields. We focus on dipolar molecules and hence we restrict ourselves to the first order interaction in field-molecule interaction potential either through permanent dipole moment or/and the molecular polarizability parameter. It is shown that confining potential shapes, strength of the confinement, strongly affect the excitation. We compare our results for different confining potentials. PMID:27387127

  5. Modeling diffusion of adsorbed polymer with explicit solvent.

    Science.gov (United States)

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

    2007-05-25

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

  6. Ordered molecular layer structure of lubricating oil adsorbed films

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    Low-angle X-ray diffraction has been applied to analyze the structure of stearic acid LB films and self-grown surface adsorbed films of aluminium product metalworking lubricants. The results show that LB films exhibit a good layer-like ordered structure in the normal direction of film-carrying surface, while in the tangential direction, they do not show a cyclically ordered molecular arrangement; as for the self-grown surface adsorbed films of aluminium sheet and strip metalworking lubricants, their molecules are orderly arranged to certain degree in both the tangential and the normal directions of film-carrying surface, and they have a short-range ordered structure. Moreover, the better the orientation of normal molecules is, the higher the oil film strength is, and the smaller the friction factor is.

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

    Directory of Open Access Journals (Sweden)

    Pavlović Marija D.

    2015-01-01

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

  8. Development of high temperature adsorbent in PWR primary system

    International Nuclear Information System (INIS)

    Radiation exposure reduction in PWR is one of the most important problems to be solved. We have developed a high temperature Co adsorbent (HTA), which could be directly applied under primary reactor coolant conditions. This adsorbent was Fe-Ti-O system ceramics, and was fabricated to a suitable form for using in a packed column. Through those experiments of adsorption tests, compatibility tests, leaching tests and hot loop tests, it was found that HTA had superior adsorption capability to not only Co and Ni-ion but also many other transition metal ions. And it was also found that HTA was compatible with high temperature water, as well as advantageous for its waste solidification. Based on the experimental results, dose reduction effect was evaluated by a computer code. From this evaluation, it was found that more than 50 % dose reduction could be expected, when an advanced reactor coolant clean-up (RCC) system with HTA would be realized. (author)

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

    Science.gov (United States)

    Gonzalez-Arraga, Luis A.; Lado, J. L.; Guinea, Francisco

    2016-09-01

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

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

    Science.gov (United States)

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

  11. Sulfometuron incorporation in cationic micelles adsorbed on montmorillonite

    OpenAIRE

    Mishael, Y. G.; Undabeytia López, Tomás; Rytwo, Giora; Papahadjopoulos Sternberg, B.; Rubin, Baruch; Nir, Shlomo

    2002-01-01

    The aim of this study was to understand the interactions between alkylammonium cations present as monomers and micelles and a clay mineral, montmorillonite, to develop slow release formulations of anionic herbicides, such as sulfometuron (SFM) whose leaching in soils is an environmental and economic problem. In the proposed formulation the herbicide is incorporated in positively charged micelles of quaternary amine cations, which in turn adsorb on the negatively charged clay. The adsorption o...

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2015-10-01

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

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

    OpenAIRE

    Kobetičová Hana; Galbičková Blanka; Ševčíková Janka; Soldán Maroš

    2014-01-01

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

  14. Dynamic scanning probe microscopy of adsorbed molecules on graphite

    OpenAIRE

    Berdunov, N.; Pollard, A J; Beton, P. H.

    2008-01-01

    We have used a combined dynamic scanning tunneling and atomic force microscope to study the organisation of weakly bound adsorbed molecules on a graphite substrate. Specifically we have acquired images of islands of the perylene derivative molecules. These weakly bound molecules may be imaged in dynamic STM, in which the probe is oscillated above the surface. We show that molecular resolution may be readily attained and that a similar mode of imaging may be realised using conventional STM arr...

  15. PREPARATION OF CHITOSAN COATED METAL AFFINITY CHROMATOGRAPHY ADSORBENT

    Institute of Scientific and Technical Information of China (English)

    AanTianwei; XuWeijiang; 等

    1998-01-01

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

  16. Equipment review: The molecular adsorbents recirculating system (MARS®)

    OpenAIRE

    Boyle, Martin; Kurtovic, Jelica; Bihari, David; Riordan, Stephen; Steiner, Christian

    2004-01-01

    The molecular adsorbents recirculating system (MARS®) is a form of artificial liver support that has the potential to remove substantial quantities of albumin-bound toxins that have been postulated to contribute to the pathogenesis of liver cell damage, haemodynamic instability and multi-organ failure in patients with acute liver failure (ALF) and acute-on-chronic liver failure (AoCLF). These toxins include fatty acids, bile acids, tryptophan, bilirubin, aromatic amino acids and nitric oxide....

  17. Adsorption capacity of various adsorbents for decolorization of wastewater

    OpenAIRE

    Romčević, Gorana

    2014-01-01

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

  18. Fate of adsorbable micropollutants through sludge drying and composting processes

    OpenAIRE

    Besnault, S.; Martin Ruel, S.; Choubert, JM.; Budzinski, H.; Miege, C.; Esperanza, M.; Noyon, N.; Garnaud, S.; Coquery, M.

    2012-01-01

    The objective of the paper was to evaluate the fate of 79 adsorbed micropollutants through 9 sludge treatment processes. A specific sampling strategy was applied to follow a “batch” of sludge through the treatment (inlet and outlet sludge, intermediary mixture for some processes such as composting and condensates). Mass balances were established to calculate micropollutants removal efficiencies and the fate of the substances through these facilities was evaluated. In order to limi...

  19. [Activity of methane-oxidizing bacteria in the adsorbed state].

    Science.gov (United States)

    Nesterov, A I; Nazarenko, A V

    1975-01-01

    Adsorption of pure cultures of methane oxidizing bacteria, Methylosinus trichosporium 20 and Methylococcus ucrainicus 21, on glass and coal was studied; the former strain was sorbed on both sorbents, the latter strain was sorbed on coal but not on glass. The rate of methane oxidation by the cells of adsorbed microorganisms was higher than in the case of free cells, and increased with a decrease in dimensions of the sorbent particles. PMID:1207502

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

    International Nuclear Information System (INIS)

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

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

    OpenAIRE

    Andrius Agintas; Marina Valentukevičienė

    2011-01-01

    Heavy metals, petroleum products, sediments and other pollutants get in the environment with insufficiently cleaned storm water runoff. Contaminated storm water runoff is one of the most significant sources for pollution in rivers, lakes and estuaries. Storm water runoff must be treated using not only simple methods but also using adsorption processes. Adsorbents can be natural organic, natural nonorganic and synthetic. Main adsorption characteristic, way of utilization and storm water runoff...

  2. Onion membrane: an efficient adsorbent for decoloring of wastewater

    OpenAIRE

    Saber-Samandari, Samaneh; Heydaripour, Jalil

    2015-01-01

    Background Recently, researchers have tried to design synthetic materials by replicating natural materials as an adsorbent for removing various types of environmental pollutants, which have reached to the risky levels in nature for many countries in the world. In this research, the potential of onion membrane obtained from intermediate of onion shells for adsorption of methylene blue (MB) as a model cationic dye was exhibited. Methods Before and after adsorption, the membrane was characterize...

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

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

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

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

    International Nuclear Information System (INIS)

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

  5. Development Trends in Porous Adsorbents for Carbon Capture.

    Science.gov (United States)

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

    2015-11-01

    Accumulation of greenhouse gases especially CO2 in the atmosphere leading to global warming with undesirable climate changes has been a serious global concern. Major power generation in the world is from coal based power plants. Carbon capture through pre- and post- combustion technologies with various technical options like adsorption, absorption, membrane separations, and chemical looping combustion with and without oxygen uncoupling have received considerable attention of researchers, environmentalists and the stake holders. Carbon capture from flue gases can be achieved with micro and meso porous adsorbents. This review covers carbonaceous (organic and metal organic frameworks) and noncarbonaceous (inorganic) porous adsorbents for CO2 adsorption at different process conditions and pore sizes. Focus is also given to noncarbonaceous micro and meso porous adsorbents in chemical looping combustion involving insitu CO2 capture at high temperature (>400 °C). Adsorption mechanisms, material characteristics, and synthesis methods are discussed. Attention is given to isosteric heats and characterization techniques. The options to enhance the techno-economic viability of carbon capture techniques by integrating with CO2 utilization to produce industrially important chemicals like ammonia and urea are analyzed. From the reader's perspective, for different classes of materials, each section has been summarized in the form of tables or figures to get a quick glance of the developments. PMID:26422294

  6. Two dimensional condensation of argon adsorbed on lamellar halides

    International Nuclear Information System (INIS)

    Lamellar halides such as NiCl2, FeCl2, NiBr2, MnBr2, MgBr2, CdBr2, CoI2, FeI2, MnI2, CaI2 and PbI2 were sublimed in a rapid stream of dry nitrogen. The adsorption of argon on such materials shows stepped isotherms which reveal two dimensional condensations. From sets of isotherms the Helmholtz free energy, the internal energy and the entropy of the successive layers are determined. From the entropy of the first layer the role of the potential relief of the adsorbent surface on the structure of the adsorbed layer may be determined while the Helmholtz free energy reveals how the ionic character of the adsorbent governs the attractive force of adsorption. The study of the second third and fourth layers shows that their growth follows quite a different behaviour depending on whether the Van der Waals diameter of argon is greater or smaller than the distance between adjacent anions on the crystal surface. A proposition is made to account for the difference in the critical temperatures of the first and second dense layers in terms of the vibrationnal state of their respective substrate. The occurence for the maximum critical temperature observed of corresponding to a triangular layer 3% more expanded than the (111) plane of solid argon is discussed

  7. Fluctuations in the number of irreversibly adsorbed particles

    Science.gov (United States)

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

    2000-12-01

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

  8. Distribution of metal and adsorbed guest species in zeolites

    International Nuclear Information System (INIS)

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

  9. Distribution of metal and adsorbed guest species in zeolites

    Energy Technology Data Exchange (ETDEWEB)

    Chmelka, B.F.

    1989-12-01

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

  10. Specific binding-adsorbent assay method and test means

    International Nuclear Information System (INIS)

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

  11. Development Trends in Porous Adsorbents for Carbon Capture.

    Science.gov (United States)

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

    2015-11-01

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

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

    Science.gov (United States)

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

    2016-06-01

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

  13. Photoinduced surface dynamics of CO adsorbed on a platinum electrode.

    Science.gov (United States)

    Noguchi, Hidenori; Okada, Tsubasa; Uosaki, Kohei

    2006-08-10

    The surface dynamics of adsorbed CO molecules formed by dissociative adsorption of HCHO at a polycrystalline Pt electrode/electrolyte solution interface was studied by picosecond time-resolved sum-frequency generation (TR-SFG) spectroscopy. A SFG peak at 2050-2060 cm(-1) was observed at the Pt electrode in HClO(4) solution containing HCHO at 0-300 mV (vs Ag/AgCl), indicating the formation of adsorbed CO at an atop site of the Pt surface as a result of dissociative adsorption of HCHO. The peak position varied with potential by approximately 33 cm(-1)/V, as previously found in an infrared reflection absorption spectroscopy (IRAS) study. Irradiation of an intense picosecond visible pulse (25 ps, 532 nm) caused an instant intensity decrease and broadening of the CO peak accompanied by the emergence of a new broad peak at approximately 1980 cm(-1) within the time resolution of the system. These results suggest a decrease and increase in the populations of CO adsorbed on atop and bridge sites, respectively, upon visible pump pulse irradiation. PMID:16884215

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

    Science.gov (United States)

    Nomura, Akihiro; Jones, Christopher W

    2013-06-26

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

  15. Structure of polymer layers adsorbed from concentrated solutions

    Science.gov (United States)

    Auvray, Loïc; Auroy, Philippe; Cruz, Margarida

    1992-06-01

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

  16. Powder-based adsorbents having high adsorption capacities for recovering dissolved metals and methods thereof

    Science.gov (United States)

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

    2016-05-03

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

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

    International Nuclear Information System (INIS)

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

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

    Science.gov (United States)

    Seko, Noriaki; Tamada, Masao; Yoshii, Fumio

    2005-07-01

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

  19. Adsorption of Heavy Metal Ions by Adsorbent from Waste Mycelium Chitin

    Institute of Scientific and Technical Information of China (English)

    苏海佳; 王丽娟; 等

    2002-01-01

    The adsorption properties of chitin adsorbent from mycelium of fermentation industries for the removal of heavy metal ions were studied.The result shows that the chitin adsorbent has high adsorption capacity for many heavy metal ions and Ni2+ in citric acid.The influence of pH was significant:When pH is higher than 4.0,the high adsorption capacity is obtained.otherwise H+ ion inhibits the adsorption of heavy metal ions.The comparison of the chitin adsorbent with some other commercial adsorbents was made,in which that the adsorption behavior of chitin adsorbent is close to that of commercial cation exchange adsorbents,and its cost is much lower than those commercial adsorbents.

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

    Institute of Scientific and Technical Information of China (English)

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

    2005-01-01

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

  1. Amine-pillared Nanosheet Adsorbents for CO2 Capture Applications

    Science.gov (United States)

    Jiang, Hui

    Amine-functionalized solid adsorbents have gained attention within the last decade for their application in carbon dioxide capture, due to their many advantages such as low energy cost for regeneration, tunable structure, elimination of corrosion problems, and additional advantages. However, one of the challenges facing this technology is to accomplish both high CO 2 capture capacity along with high CO2 diffusion rates concurrently. Current amine-based solid sorbents such as porous materials similar to SBA-15 have large pores diffusion entering molecules; however, the pores become clogged upon amine inclusion. To meet this challenge, our group's solution involves the creation of a new type of material which we are calling-amino-pillared nanosheet (APN) adsorbents which are generated from layered nanosheet precursors. These materials are being proposed because of their unique lamellar structure which exhibits ability to be modified by organic or inorganic pillars through consecutive swelling and pillaring steps to form large mesoporous interlayer spaces. After the expansion of the layer space through swelling and pillaring, the large pore space can be functionalized with amine groups. This selective functionalization is possible by the choice of amine group introduced. Our choice, large amine molecules, do not access the micropore within each layer; however, either physically or chemically immobilized onto the surface of the mesoporous interlayer space between each layer. The final goal of the research is to investigate the ability to prepare APN adsorbents from a model nanoporous layered materials including nanosheets precursor material MCM-22(P) and nanoporous layered silicate material AMH-3. MCM-22(P) contains 2-dimensional porous channels, 6 membered rings (MB) openings perpendicular to the layers and 10 MB channels in the plane of the layers. However, the transport limiting openings (6 MB) to the layers is smaller than CO2 gas molecules. In contrast, AMH-3 has

  2. A DFT study of halogen atoms adsorbed on graphene layers

    Energy Technology Data Exchange (ETDEWEB)

    Medeiros, Paulo V C; De Brito Mota, F; De Castilho, Caio M C [Grupo de Fisica de Superfcies e Materiais, Instituto de Fisica, Universidade Federal da Bahia, Campus Universitario da Federacao/Ondina, 40170-115 Salvador, Bahia (Brazil); Mascarenhas, Artur J S, E-mail: caio@ufba.br [Instituto Nacional de Ciencia e Tecnologia em Energia e Ambiente-INCT-E and A, Universidade Federal da Bahia, 40170-280 Salvador, Bahia (Brazil)

    2010-12-03

    In this work, ab initio density functional theory calculations were performed in order to study the structural and electronic properties of halogens (X = fluorine, chlorine, bromine or iodine) that were deposited on both sides of graphene single layers (X-graphene). The adsorption of these atoms on only one side of the layer with hydrogen atoms adsorbed on the other was also considered (H,X-graphene). The results indicate that the F-C bond in the F-graphene system causes an sp{sup 2} to sp{sup 3} transition of the carbon orbitals, and similar effects seem to occur in the H,X-graphene systems. For the other cases, two configurations are found: bonded (B) and non-bonded (NB). For the B configuration, the structural arrangement of the atoms was similar to F-graphene and H-graphene (graphane), although the electronic structures present some differences. In the NB configuration, the interaction between the adsorbed atoms and the graphene layer seems to be essentially of the van der Waals type. In these cases, the original shape of the graphene layer presents only small deviations from the pristine form and the adsorbed atoms reach equilibrium far from the sheet. The F-graphene structure has a direct bandgap of approximately 3.16 eV at the {Gamma} point, which is a value that is close to the value of 3.50 eV that was found for graphane. The Cl-graphene (B configuration), H,F-graphene and H,Cl-graphene systems have smaller bandgap values. All of the other systems present metallic behaviours. Energy calculations indicate the possible stability of these X-graphene layers, although some considerations about the possibility of spontaneous formation have to be taken into account.

  3. Controllable Catalysis with Nanoparticles: Bimetallic Alloy Systems and Surface Adsorbates

    KAUST Repository

    Chen, Tianyou

    2016-05-16

    Transition metal nanoparticles are privileged materials in catalysis due to their high specific surface areas and abundance of active catalytic sites. While many of these catalysts are quite useful, we are only beginning to understand the underlying catalytic mechanisms. Opening the “black box” of nanoparticle catalysis is essential to achieve the ultimate goal of catalysis by design. In this Perspective we highlight recent work addressing the topic of controlled catalysis with bimetallic alloy and “designer” adsorbate-stabilized metal nanoparticles.

  4. Graphene symmetry-breaking with molecular adsorbates: modeling and experiment

    Science.gov (United States)

    Groce, M. A.; Hawkins, M. K.; Wang, Y. L.; Cullen, W. G.; Einstein, T. L.

    2012-02-01

    Graphene's structure and electronic properties provide a framework for understanding molecule-substrate interactions and developing techniques for band gap engineering. Controlled deposition of molecular adsorbates can create superlattices which break the degeneracy of graphene's two-atom unit cell, opening a band gap. We simulate scanning tunneling microscopy and spectroscopy measurements for a variety of organic molecule/graphene systems, including pyridine, trimesic acid, and isonicotinic acid, based on density functional theory calculations using VASP. We also compare our simulations to ultra-high vacuum STM and STS results.

  5. Sustainable catalyst supports for carbon dioxide gas adsorbent

    Science.gov (United States)

    Mazlee, M. N.

    2016-07-01

    The adsorption of carbon dioxide (CO2) become the prime attention nowadays due to the fact that increasing CO2 emissions has been identified as a contributor to global climate change. Major sources of CO2 emissions are thermoelectric power plants and industrial plants which account for approximately 45% of global CO2 emissions. Therefore, it is an urgent need to develop an efficient CO2 reduction technology such as carbon capture and storage (CCS) that can reduce CO2 emissions particularly from the energy sector. A lot of sustainable catalyst supports have been developed particularly for CO2 gas adsorbent applications.

  6. Detection of adsorbed water and hydroxyl on the moon

    Science.gov (United States)

    Clark, R.N.

    2009-01-01

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

  7. 3,5-Dichlorophenol Removal From Wastewater Using Alternative Adsorbents

    Directory of Open Access Journals (Sweden)

    Kobetičová Hana

    2015-06-01

    Full Text Available The main objective of this paper is to evaluate the efficiency of 3,5-dichlorophenol removal from wastewater by using alternative low cost adsorbents. Waste from the production and processing of metals (black nickel mud, red mud and a biosorbent (Lemna minor were used for this research. Initial concentration of the contaminant was 4 mmol L−1, the contact time of sorbent and waste water was 0 - 48 hrs and the temperature during experiment was 25 ± 0.2 °C. The results show that the highest removal efficiency of 3,5 - dichlorophenol (58.18 % was reached by the red mud in 48 hours.

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

    Directory of Open Access Journals (Sweden)

    Kobetičová Hana

    2014-12-01

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

  9. 3,5-Dichlorophenol Removal From Wastewater Using Alternative Adsorbents

    Science.gov (United States)

    Kobetičová, Hana; Lipovský, Marek; Wachter, Igor; Soldán, Maroš

    2015-06-01

    The main objective of this paper is to evaluate the efficiency of 3,5-dichlorophenol removal from wastewater by using alternative low cost adsorbents. Waste from the production and processing of metals (black nickel mud, red mud) and a biosorbent (Lemna minor) were used for this research. Initial concentration of the contaminant was 4 mmol L-1, the contact time of sorbent and waste water was 0 - 48 hrs and the temperature during experiment was 25 ± 0.2 °C. The results show that the highest removal efficiency of 3,5 - dichlorophenol (58.18 %) was reached by the red mud in 48 hours.

  10. Magnetically modified microbial cells: A new type of magnetic adsorbents

    Institute of Scientific and Technical Information of China (English)

    Ivo; Safarik; Mirka; Safarikova

    2007-01-01

    Microbial cells, either in free or immobilized form, can be used for the preconcentration or removal of metal ions, organic and inorganic xenobiotics or biologically active compounds. Magnetic modification of these cells enables to prepare magnetic adsorbents that can be easily manipulated in difficult-to-handle samples, such as suspensions, in the presence of external magnetic field. In this review, typical examples of magnetic modifications of microbial cells are presented, as well as their possible applications for the separation of organic xenobiotics and heavy metal ions.

  11. Temperature programmed desorption of weakly bound adsorbates on Au(111)

    Science.gov (United States)

    Engelhart, Daniel P.; Wagner, Roman J. V.; Meling, Artur; Wodtke, Alec M.; Schäfer, Tim

    2016-08-01

    We have performed temperature programmed desorption (TPD) experiments to analyze the desorption kinetics of Ar, Kr, Xe, C2H2, SF6, N2, NO and CO on Au(111). We report desorption activation energies (Edes), which are an excellent proxy for the binding energies. The derived binding energies scale with the polarizability of the molecules, consistent with the conclusion that the surface-adsorbate bonds arise due to dispersion forces. The reported results serve as a benchmark for theories of dispersion force interactions of molecules at metal surfaces.

  12. Behavior of adsorbed Poly-A onto sodium montmorillonite

    Energy Technology Data Exchange (ETDEWEB)

    Palomino-Aquino, Nayeli [Facultad de Estudios Superiores Iztacala, Universidad Nacional Autónoma de México (Mexico); Negrón-Mendoza, Alicia, E-mail: negron@nucleares.unam.mx [Instituto de Ciencias Nucleares, Universidad Nacional Autónoma de México (Mexico)

    2015-07-23

    The adsorption of Poly-A (a polynucleotide consisting of adenine, ribose and a phosphate group), onto a clay mineral, was studied to investigate the extent of adsorption, the site of binding, and the capacity of the clay to protect Poly-A, while it is adsorbed onto the clay, from external sources of energy. The results showed that Poly-A presented a high percentage of adsorption at the edges of the clay and that the survival of the polynucleotide was superior to irradiating the polymer in the absence of the clay.

  13. Structure of adsorbed monolayers. The surface chemical bond

    International Nuclear Information System (INIS)

    This paper attempts to provide a summary of what has been learned about the structure of adsorbed monolayers and about the surface chemical bond from molecular surface science. While the surface chemical bond is less well understood than bonding of molecules in the gas phase or in the solid state, our knowledge of its properties is rapidly accumulating. The information obtained also has great impact on many surface science based technologies, including heterogeneous catalysis and electronic devices. It is hoped that much of the information obtained from studies at solid-gas interfaces can be correlated with molecular behavior at solid-liquid interfaces. 31 references, 42 figures, 1 table

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

    Science.gov (United States)

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

    2013-08-01

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

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

    International Nuclear Information System (INIS)

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

  16. Heterogeneous radiolysis of HCN adsorbed on a solid surface

    Energy Technology Data Exchange (ETDEWEB)

    Colin-Garcia, M.; Ortega-Gutierrez, F. [Instituto de Geologia, Universidad Nacional Autonoma de Mexico, Ciudad Universitaria, 04510 Mexico D.F. (Mexico); Ramos-Bernal, S. [Instituto de Ciencias Nucleares, Universidad Nacional Autonoma de Mexico, Ciudad Universitaria, 04510 Mexico D.F. (Mexico); Negron-Mendoza, A., E-mail: negron@nucleares.unam.m [Instituto de Ciencias Nucleares, Universidad Nacional Autonoma de Mexico, Ciudad Universitaria, 04510 Mexico D.F. (Mexico)

    2010-07-21

    Hydrogen cyanide is a key molecule for chemical evolution studies because, when it is exposed to different sources of energy, it forms various compounds of biological importance. To understand the role of minerals in chemical evolution, a series of experiments was performed. First, the adsorption capacity of HCN on different surface minerals was studied; the results show that HCN is readily adsorbed onto the solids proposed (zeolite, serpentine, dolomite, and sodium montmorillonite), in particular zeolite and montmorillonite. Second, the radiolysis of HCN adsorbed on olivine (as an example of a mineral surface) was also followed; it was found that the rate of HCN decomposition by gamma irradiation is enhanced in the presence of the solid. The third series of studies show that organic material was produced in high abundance from HCN at high radiation doses. The radiolytic products included gases (CO{sub 2}, NH{sub 4}, and CO) and oligomeric materials that release carboxylic acids (succinic, malonic, citric, and tricarballylic acids) and amino acids upon acid hydrolysis. These experiments suggest that minerals could have participated actively in chemical evolution processes.

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

    Energy Technology Data Exchange (ETDEWEB)

    Tallent, O.K.; Mailen, J.C.; Pannell, K.D.

    1984-06-01

    A solvent cleanup method using silica gel columns treated with either sodium hydroxide (NaOH) or lithium hydroxide (LiOH) has been investigated. Its effectiveness compares favorably with that of traditional wash methods. After treatment with NaOH solution, the gels adsorb HNO/sub 3/, dibutyl phosphate (DBP), UO/sub 2//sup 2 +/, Pu/sup 4 +/, various metal-ion fission products, and other species from the solvent. Adsorption mechanisms include neutralization, hydrolysis, polymerization, and precipitation, depending on the species adsorbed. Sodium dibutyl phosphate, which partially distributes to the solvent from the gels, can be stripped with water; the stripping coefficient ranges from 280 to 540. Adsorption rates are diffusion controlled such that temperature effects are relatively small. Recycle of the gels is achieved either by an aqueous elution and recycle sequence or by a thermal treatment method, which may be preferable. Potential advantages of this solvent cleanup method are that (1) some operational problems are avoided and (2) the amount of NaNO/sub 3/ waste generated per metric ton of nuclear fuel reprocessed would be reduced significantly. 19 references, 6 figures, 12 tables.

  18. Home-made carbonaceous adsorbents for the iodine filter

    International Nuclear Information System (INIS)

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

  19. Adsorbate Electric Fields on a Cryogenic Atom Chip

    CERN Document Server

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

    2013-01-01

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

  20. Fibrous adsorbent for removal of aqueous aromatic hydrocarbons.

    Science.gov (United States)

    Jung, Yong-Jun; Kiso, Yoshiaki; Oguchi, Tatsuo; Yamada, Toshiro; Takagi, Hiroo; Nishimura, Kazuyuki

    2007-01-01

    Bundles of a strongly hydrophobic fibrous material (p-phenylene-2,6-benzobisoxazole; PBO; Zylon) were employed as an adsorbent for the removal of aqueous aromatic compounds, because the PBO fibers are too rigid to be woven and did not entrap suspended solids. The removal performance for nine kinds of polyaromatic hydrocarbons (PAHs) and di-(2-ethylhexyl) phthalate (DEHP) was evaluated. PAHs and DEHP at initial concentrations of 50 microg L(-1) were removed at 72.5-99.9% and ca. 95%, respectively, although the removal efficiencies were affected by the phase ratio (fiber weight/solution volume). The logarithm of the partition coefficient (log K) for planar PAHs was linearly correlated with the logarithm of the n-octanol/water partition coefficient (log P), but nonplanar PAHs, such as cis-stilbene, p-terphenyl, and o-terphenyl, showed significantly lower adsorption performance. The adsorbed PAHs were not desorbed effectively with CH3CN, CH2Cl2, and toluene. On the other hand, DEHP was effectively desorbed with methanol.

  1. Ceramics adsorbing virus and cells. Uirusu, saibo bunri ceramics

    Energy Technology Data Exchange (ETDEWEB)

    Hiraide, T. (Asahi Optical Co. Ltd., Tokyo (Japan))

    1993-07-01

    It has been reported that hydroxyapatite (HA), which is the main inorganic component of teeth and bones of homo sapiens and used for biomaterials such as artificial tooth roots, adsorbs viruses such as influenza viruses. In this article, the history of development up to now of HA and its adsorption mechanism of protein, virus, etc., are introduced. HA was applied for chromatography in 1956 becoming one of the separating and refining methods of protein and nucleic acid, then after the development of spherical porous HA, it has become applied for high speed liquid chromatography (HPLC). Also by means of a column filled with HA granules, T-cells have been able to be purified in a short time from lymphocyte which was separated from the blood of homo sapiens. Recently it has also been reported that HA granules can adsorb influenza viruses, Japanese encephalitis viruses, polio viruses and hepatitis B viruses, and a cold-preventative mask based upon this report is now on sale. 11 refs., 7 figs.

  2. Structure of Inert Gases Adsorbed in MCM-41

    Science.gov (United States)

    Evans, Dylan; Sokol, Paul

    One-dimensional quantum liquids of 3He or 4He have generated recent interest for investigation in the Luttinger liquid model. Unfortunately, current studies lack a clear demonstration of definitively one-dimensional behavior. We propose using the templated, porous material, MCM-41, as a host for an atomic Luttinger liquid. In general, the pores of MCM-41 are too wide to provide a strictly one-dimensional environment, so we investigate preplating these pores with inert gases to effectively reduce their diameter. We present the results of studies of the structure of inert gases in MCM-41. Nitrogen sorption isotherms were used to characterize the sample. Then, using inert gases as adsorbates, we determined the minimum effective pore diameter that can be achieved in our sample before capillary condensation takes over. X-ray powder diffraction (XRD) was performed on the ideally preplated sample to investigate the structure of the adsorbates in the nanopores. The XRD measurements are compared to simulations of core-shell cylinder model scattering, and the validity of the model is assessed. The prospects for creating a definitively one-dimensional channel for the application of studying the structure and dynamics of helium confined in one dimension are discussed. This work was supported by the National Science Foundation under Grant DGE-1069091.

  3. Fibrous adsorbent for removal of aqueous aromatic hydrocarbons.

    Science.gov (United States)

    Jung, Yong-Jun; Kiso, Yoshiaki; Oguchi, Tatsuo; Yamada, Toshiro; Takagi, Hiroo; Nishimura, Kazuyuki

    2007-01-01

    Bundles of a strongly hydrophobic fibrous material (p-phenylene-2,6-benzobisoxazole; PBO; Zylon) were employed as an adsorbent for the removal of aqueous aromatic compounds, because the PBO fibers are too rigid to be woven and did not entrap suspended solids. The removal performance for nine kinds of polyaromatic hydrocarbons (PAHs) and di-(2-ethylhexyl) phthalate (DEHP) was evaluated. PAHs and DEHP at initial concentrations of 50 microg L(-1) were removed at 72.5-99.9% and ca. 95%, respectively, although the removal efficiencies were affected by the phase ratio (fiber weight/solution volume). The logarithm of the partition coefficient (log K) for planar PAHs was linearly correlated with the logarithm of the n-octanol/water partition coefficient (log P), but nonplanar PAHs, such as cis-stilbene, p-terphenyl, and o-terphenyl, showed significantly lower adsorption performance. The adsorbed PAHs were not desorbed effectively with CH3CN, CH2Cl2, and toluene. On the other hand, DEHP was effectively desorbed with methanol. PMID:17585293

  4. Contact and friction of nanoasperities: effects of adsorbed monolayers.

    Science.gov (United States)

    Cheng, Shengfeng; Luan, Binquan; Robbins, Mark O

    2010-01-01

    Molecular dynamics simulations are used to study contact between a rigid, nonadhesive, and spherical tip with radius of order 30 nm and a flat elastic substrate covered with a fluid monolayer of adsorbed chain molecules. Previous studies of bare surfaces showed that the atomic scale deviations from a sphere that are present on any tip constructed from discrete atoms lead to significant deviations from continuum theory and dramatic variability in friction forces. Introducing an adsorbed monolayer leads to larger deviations from continuum theory but decreases the variations between tips with different atomic structure. Although the film is fluid, it remains in the contact and behaves qualitatively like a thin elastic coating except for certain tips at high loads. Measures of the contact area based on the moments or outer limits of the pressure distribution and on counting contacting atoms are compared. The number of tip atoms making contact during a time interval Deltat grows as a power of Deltat when the film is present and as the logarithm of Deltat for bare surfaces. Friction is measured by displacing the tip at a constant velocity or pulling the tip with a spring. Both static and kinetic friction rise linearly with load at small loads. Transitions in the state of the film lead to nonlinear behavior at large loads. The friction is less clearly correlated with contact area than load. PMID:20365427

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

    International Nuclear Information System (INIS)

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

  6. Dynamics of different molecules adsorbed in porous media

    Indian Academy of Sciences (India)

    S Mitra; V S Kamble; A K Tripathi; N M Gupta; R Mukhopadhyay

    2004-08-01

    We present in this paper a comparative study on the dynamics of benzene, cyclohexane, and methanol molecules, confined in the pores of MCM-41 molecular sieve and HZSM-5 zeolite. The quasi-elastic neutron scattering (QENS) measurements revealed that the physical state of these adsorbed molecules depended not only on the structural characteristics of the host matrix but also on the chemical properties, such as dipole moment, of the guest molecules. Thus, while no motion was observed in the time-scale of 10−10 –10−12 s in the case of methanol, the larger size benzene and cyclohexane molecules are found to perform six-fold and three-fold jump rotation, respectively, when adsorbed inside the cages of HZSM-5 at room temperature. At the same time, all the three molecules are found to undergo a translational motion inside the pores of MCM-41 molecular sieves, the value of diffusion constant being the lowest in case of methanol because of its higher polarity. Translationl motion of the guest molecules inside the pores of MCM-41 can be satisfactorily described by Chudley–Eliott fixed jump length diffusion and accordingly the residence time, jump length and diffusion constant are estimated.

  7. Vibrational spectroscopic studies of adsorbates on bimetallic surfaces. Doctoral thesis

    Energy Technology Data Exchange (ETDEWEB)

    Kuhn, W.K.

    1992-12-01

    In this work, well-defined bimetallic surfaces have been studied using carbon monoxide adsorption in conjunction with infrared reflection absorption spectroscopy (IRAS). These studies have indicated that for CO adsorbed on Cu overlayers, the bond between the CO and the Cu adatoms is comprised of both pi-back-donation and polarization interaction components. The sum of the contributions from these effects determines the observed bond strength with the observed CO stretching frequency being determined by the relative contributions of the components. In addition, it was determined that IR spectra of adsorbed CO show a remarkable sensitivity to surface structure. Three-dimensional Cu clusters, well-ordered two dimensional Cu islands and isolated Cu atoms are distinctively characterized by their CO IR peaks. In addition, both disorder-order and order-order transitions are observed for the metal overlayers on the single crystal metal substrates. It was also observed that localized segregation and ordering of mixed Co and S overlayers on a Mo(110) substrate occurs upon annealing.

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

    Directory of Open Access Journals (Sweden)

    S.H. Suseno

    2014-01-01

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

  9. Palladium dimers adsorbed on graphene: A DFT study

    Energy Technology Data Exchange (ETDEWEB)

    Kaur, Gagandeep, E-mail: gaganj1981@yahoo.com [Department of Physics and Centre of Advanced Studies in Physics, Panjab University, Chandigarh-160014 (India); Chandigarh Engineering College, Landran, Mohali, Punjab (India); Gupta, Shuchi, E-mail: sgupta@pu.ac.in [University Institute of Engineering and Technology, Panjab University, Chandigarh -160014 (India); Dharamvir, Keya, E-mail: keya@pu.ac.in [Department of Physics and Centre of Advanced Studies in Physics, Panjab University, Chandigarh-160014 (India)

    2015-05-15

    The 2D structure of graphene shows a great promise for enhanced catalytic activity when adsorbed with palladium. We performed a systematic density functional theory (DFT) study of the adsorption of palladium dimer (Pd{sub 2}) on graphene using SIESTA package, in the generalized gradient approximation (GGA). The adsorption energy, geometry, and charge transfer of Pd{sub 2}-graphene system are calculated. Both horizontal and vertical orientations of Pd{sub 2} on graphene are studied. Our calculations revealed that the minimum energy configuration for Pd dimer is parallel to the graphene sheet with its two atoms occupying centre of adjacent hexagonal rings of graphene sheet. Magnetic moment is induced for Pd dimer adsorbed on graphene in vertical orientation while horizontal orientation of Pd dimer on graphene do not exhibit magnetism. Insignificant energy differences among adsorption sites means that dimer mobility on the graphene sheet is high. There is imperceptible distortion of graphene sheet perpendicular to its plane. However, some lateral displacements are seen.

  10. Mercury(II Removal with Modified Magnetic Chitosan Adsorbents

    Directory of Open Access Journals (Sweden)

    George Z. Kyzas

    2013-05-01

    Full Text Available Two modified chitosan derivatives were prepared in order to compare their adsorption properties for Hg(II removal from aqueous solutions. The one chitosan adsorbent (CS is only cross–linked with glutaraldehyde, while the other (CSm, which is magnetic, is cross-linked with glutaraldehyde and functionalized with magnetic nanoparticles (Fe3O4. Many possible interactions between materials and Hg(II were observed after adsorption and explained via characterization with various techniques (SEM/EDAX, FTIR, XRD, DTG, DTA, VSM, swelling tests. The adsorption evaluation was done studying various parameters as the effect of pH (optimum value 5 for adsorption and 2 for desorption, contact time (fitting to pseudo–first, –second order and Elovich equations, temperature (isotherms at 25, 45, 65 °C, in line with a brief thermodynamic analysis (ΔG0 0, ΔS0 > 0. The maximum adsorption capacity (fitting with Langmuir and Freundlich model of CS and CSm at 25 °C was 145 and 152 mg/g, respectively. The reuse ability of the adsorbents prepared was confirmed with sequential cycles of adsorption-desorption.

  11. Work function of alkali metal-adsorbed molybdenium dichalcogenides

    Science.gov (United States)

    Kim, Sol; Jhi, Seung-Hoon

    2015-03-01

    The lowest work function of materials, reported so far over the last few decades, is an order of 1eV experimentally and theoretically. Designing materials that has work-function less than 1eV is essential in the thermionic energy conversion. To explore new low work function materials, we study MoX2(X =S, Se, Te) adsorbed with alkali metals (Li, Na, K, Rb and Cs), and investigate the charge transfer, the formation of surface dipole, and the change in work function using first-principles calculations. It is found that the charge transfer from alkali metals to MoX2substrates decreases as the atomic number of adsorbates increases. Regardless of the amount of the charge transfer, K on MoTe2 exhibits the biggest surface dipole moment, which consequently makes the surface work function the lowest. We show that the formation of the surface dipole is a key in changing the work function. We find the trimerization of Mo atoms in the substrate with the lowest work-function, which may contribute to enhancement of the surface dipole.

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

    Science.gov (United States)

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

    2013-04-01

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

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

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Taewoon; Lee, Seung-Kon; Lee, Suseung; Lee, Jun Sig [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2015-10-15

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

  14. The Impact of Enzyme Orientation and Electrode Topology on the Catalytic Activity of Adsorbed Redox Enzymes

    Science.gov (United States)

    McMillan, Duncan G. G.; Marritt, Sophie J.; Kemp, Gemma L.; Gordon-Brown, Piers; Butt, Julea N.; Jeuken, Lars J. C.

    2014-01-01

    It is well established that the structural details of electrodes and their interaction with adsorbed enzyme influences the interfacial electron transfer rate. However, for nanostructured electrodes, it is likely that the structure also impacts on substrate flux near the adsorbed enzymes and thus catalytic activity. Furthermore, for enzymes converting macro-molecular substrates it is possible that the enzyme orientation determines the nature of interactions between the adsorbed enzyme and substrate and therefore catalytic rates. In essence the electrode may impede substrate access to the active site of the enzyme. We have tested these possibilities through studies of the catalytic performance of two enzymes adsorbed on topologically distinct electrode materials. Escherichia coli NrfA, a nitrite reductase, was adsorbed on mesoporous, nanocrystalline SnO2 electrodes. CymA from Shewanella oneidensis MR-1 reduces menaquinone-7 within 200 nm sized liposomes and this reaction was studied with the enzyme adsorbed on SAM modified ultra-flat gold electrodes. PMID:24634538

  15. The Impact of Enzyme Orientation and Electrode Topology on the Catalytic Activity of Adsorbed Redox Enzymes.

    Science.gov (United States)

    McMillan, Duncan G G; Marritt, Sophie J; Kemp, Gemma L; Gordon-Brown, Piers; Butt, Julea N; Jeuken, Lars J C

    2013-11-01

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

  16. EFFECT OF WEAK INTERACTIONS ON PHENOL ADSORPTION FROM AQUEOUS SOLUTIONS BY AMINATED POLYMERIC ADSORBENTS

    Institute of Scientific and Technical Information of China (English)

    Wei-ming Zhang; Jin-long Chen; Ai-min Li; Bing-cai Pan; Qun Chen; Ming-yang He; Quan-xing Zhang

    2006-01-01

    Adsorption behaviors of phenol from aqueous solutions have been investigated in batch systems at 303 K and 318 K respectively, using hypercrosslinked polymeric adsorbent (CHA 111), aminated hypercrosslinked polymeric adsorbents (NDA101, NDA 103, NDA105) and weakly basic polymeric adsorbent (D301) with a view to studying the effect of hydrogen bonding and Van der Waals interactions between adsorbate and the adsorbent. All adsorption isotherms can be well fitted by Langmuir and Freundlich equations. Compared with D301 driven by hydrogen bonding interaction only and CHA111 driven by Van der Waals interaction only, phenol adsorption on aminated adsorbents driven by both hydrogen bonding and Van der Waals interactions were apparently different, i.e., negative effect for NDA105, positive effect for NDA101 and synergistic effect for NDA103. In this synergistic action, some weak interactions would contribute more or less to the adsorption than they work individually.

  17. A WATER—COMPATIBLE PHENOLIC HYDROXYL ODIFIED POLYSTYRENE AS AN ADSORBENT FOR ADSORBING PHENOLIC COMPOUNDS FROM AQUEOUS SOLUTIONS

    Institute of Scientific and Technical Information of China (English)

    LIAimin; FeiZhenghao; 等

    2001-01-01

    A water-compatible phenolic hydroxyl modified polystyrene adsorbent (AM-1) for adsorbing and removing phenolic compounds from aqueous solutions was prepared by covalent bonding of phenolic hydroxyl groups to the surface of porous polystyrene-divinylbenzene beads,this resin can be used directly without wetting process.A comparison of the sorption properites of the new resin and Amberlite XAD-4 toward four phenolic compounds,phenol,p-cresol,p-chlorophenol,and p-nitrophenol was made.The capacities of equilibrium adsorption of AM-1 for all four phenolic compounds increased around 20% over that of Amberlite XAD-4,which may be contributed to pheonl hydroxyl group on the surface and the unusual poe distribution.At their dilute solution,the equilibrium adsorption capacities of AM-1 for phenol increased aout 62% over that of Amberlite XAD-4,while equilibrium adsorption capacities of the other three phenolic compounds increased 4-35%,suggesting an advantage of AM-1 over Amberlite XAD-4 in the collection of phenol.Freundlich isotherm equations and isosteric adsorption enthalpies for the four phenolic compunds indicate a physical adsorption process on the Amberlite XAD-4 and AM-1 resins,Column studies for phenol show that AM-1 resin has excellent adsorption and desorption performance.

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

    International Nuclear Information System (INIS)

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

  19. The origin and characterization of conformational heterogeneity in adsorbed polymer layers

    Science.gov (United States)

    Douglas, Jack F.; Schneider, Hildegard M.; Frantz, Peter; Lipman, Robert; Granick, Steve

    1997-09-01

    The equilibration of polymer conformations tends to be sluggish in polymer layers adsorbed onto highly attractive substrates, so the structure of these layers must be understood in terms of the layer growth process rather than equilibrium theory. Initially adsorbed chains adopt a highly flattened configuration while the chains which arrive later must adapt their configurations to the increasingly limited space available for adsorption. Thus, the chains adsorbed in the late stage of deposition are more tenuously attached to the surface. This type of non-equilibrium growth process is studied for polymethylmethacrylate (PMMA) adsorbed on oxidized silicon where the segmental attraction is strong (0953-8984/9/37/005/img7/segment) and for polystyrene (PS) adsorbed on oxidized silicon from a carbon tetrachloride solution where the segmental attraction is relatively weak (0953-8984/9/37/005/img8/segment). Measurements were based on Fourier transform infrared spectroscopy in attenuated total reflection (FTIR - ATR). In both cases, the chains arriving first adsorbed more tightly, became flattened (as measured by the dichroic ratio), and occupied a disproportionately large fraction of the surface. This non-uniform structure persisted indefinitely for the strongly adsorbed PMMA chains, while the PS chains exhibited a gradual evolution, presumably reflecting an equilibration of the adsorbed layer occurring after long times. On the theoretical side, the initial heterogeneity of these adsorbed polymer layers is modelled using a random sequential adsorption (RSA) model where the size of the adsorbing species is allowed to adapt to the surface space available at the time of adsorption. The inhomogeneity in the size of adsorbing species (hemispheres) in this model is similar to the distribution of chain contacts in our measurements on adsorbed polymer layers. Owing to extensive variance around the mean, conformations having the mean number of chain contacts are least probable, which

  20. Attractive and repulsive interactions between and within adsorbed ribonuclease A layers.

    OpenAIRE

    Belfort, G; Lee, C S

    1991-01-01

    Adsorbed layers of pancreatic RNase A on molecularly smooth mica in aqueous solution attract inorganic mica surfaces whereas they repel similarly adsorbed RNase A layers. As the clean mica surface is covered with RNase A, the attractive interaction slowly diminishes with time and eventually converts to a purely repulsive interaction. Solvent is squeezed out of the solution in the gap during compression of the two surfaces so that the adsorbed protein concentration, as measured directly by the...

  1. Theory of Inelastic Tunneling Current-Driven Motions of Single Adsorbates (Review Article)

    OpenAIRE

    Ueba, H.; Tikhodeev, S. G.; Persson, B.N.J.

    2010-01-01

    The theory of inelastic electron tunneling spectroscopy (IETS) and motions of single adsorbed atoms and molecules on metal surfaces induced by vibrational excitation with a scanning tunneling microscope (STM) is reviewed. The theory of STM-IETS is described using the adsorbate-induced resonance model. Elementary processes of how an adsorbate overcomes the potential barrier along the reaction coordinate (RC) by inelastic tunneling current are described with a focus on direct excitation of the ...

  2. Experimental and Numerical Investigation of Enhancement of Heat and Mass Transfer in Adsorbent Beds

    Institute of Scientific and Technical Information of China (English)

    LiuZhenyan; FuZhumantffu

    1994-01-01

    Some interrelated parameters of heat and mass transfer in two phases of pressure rise and constant pressure are obtained by studying the desorption processes of two kinds of cylindrical adsorbent beds.with fins and without fins.Moreover,the effects of equivalent thermal conductivity of adsorbent beds,contact thermal transfer coefficient,heat transfer of fins,condensation temperature,uncondensable gas in the adsorber are analyzed.finally,enhancement of heat and mass transfer has been attained.

  3. The Removal of Dye from Aqueous Solution by Adsorption on Low Cost Adsorbents

    OpenAIRE

    J. J. Chamargore; Bharad, J. V.; Madje, B. R.; Ubale, M. B.

    2010-01-01

    Removal of color from aqueous solution by using low cost easily available adsorbent was conducted by batch experiment. The potential of the low cost adsorbent (Marble powder-treated and untreated) to remove methylene red from aqueous solution were assessed at room temperature. Laboratory investigation of the potential of marble powder and sulphuric acid treated marble powder to remove dye color from aqueous solution has been studied. Parameters studied included pH, adsorbent dose, initial dye...

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

    OpenAIRE

    Zwain, Haider M.; Mohammadtaghi Vakili; Irvan Dahlan

    2014-01-01

    This review examines a variety of adsorbents and discusses mechanisms, modification methods, recovery and regeneration, and commercial applications. A summary of available researches has been composed by a wide range of potentially low-cost modified adsorbents including activated carbon, natural source adsorbents (clay, bentonite, zeolite, etc.), biosorbents (black gram husk, sugar-beet pectin gels, citrus peels, banana and orange peels, carrot residues, cassava waste, algae, algal, marine gr...

  5. Performance of Laterite Soil Grains as Adsorbent in the Removal of Chromium

    OpenAIRE

    Syama I J; Arun Kumar Thalla; Manu D S

    2015-01-01

    The present study aims to examine the efficiency of laterite grains (LG) and acid activated laterite grains (AALG) as an adsorbent for removal hexavalent chromium and ferric ion from synthetic wastewater, under laboratory conditions. Adsorption of hexavalent chromium and ferric ion from synthetic wastewater is examined by batch and column studies wherein it is found to be dependent on pH, Contact time, adsorbent dosage and initial adsorbate concentration. Percentage removal enhances with the ...

  6. Calculation of Henry constant on the base of critical parameters of adsorbable gas

    International Nuclear Information System (INIS)

    Calculation of Henry constant using correlation between critical parameters Psub(c), Tsub(c) and adsorption energy, determined by the value of internal pressure in molecular field of adsorbent, has been made. The calculated Henry constants for Ar, Kr and Xe, adsorbed by MoS2 and zeolite NaX, are compared with the experimental ones. The state of the molecules adsorbed is evaluated

  7. Preparation of the fibrous adsorbent containing amidoxime group or triazine group

    International Nuclear Information System (INIS)

    Amidoxime fiber and triazine fiber were prepared by chemical modification of commercially available polyacrylonitril fiber. It was found that the amidoxime fiber is efficient to adsorb uranium ions in the artificial seawater. The efficency of the preferential adsorption decreases by treatment the material with an acid or an alkaline solution. The triazine fiber adsorbs uranium ions only in aqueous solutions of such uranyl acetate, in the absence of other ions. In the artificial seawater, it adsorbs other ions instead of uranium. (author)

  8. CONDUCTIVITY METHOD APPLIED TO THE STUDY OF INTERACTION BETWEEN ADSORBENT AND ADSORBATE I.ADSORPTION OF LOW CONCENYRATION OF FREE ACID BY REGENERABLE CHITIN

    Institute of Scientific and Technical Information of China (English)

    ChenBingren; HeGuangping; 等

    1997-01-01

    The adsorption of low concentration of free acid by regenerable chitin is followed by electric conductance determination.The effect of acid concentratioin,content of functioinal amino groups,and ionic strength on adsorption was discussed.Experimental results indicate that the active centre of regenerable chitin is the free amino groups on ist surface ,and that the rate of adsorption of free acid was found to be affected by two factors:the interaction between the adsorbent and the adsorbate in solution and that between the adsorbate molecules or ions in solution.

  9. Detection of adsorbed explosive molecules using thermal response of suspended microfabricated bridges

    DEFF Research Database (Denmark)

    Yi, Dechang; Greve, Anders; Hales, Jan Harry;

    2008-01-01

    Here we present a thermophysical technique that is capable of differentiating vapor phase adsorbed explosives from nonexplosives and is additionally capable of differentiating individual species of common explosive vapors. This technique utilizes pairs of suspended microfabricated silicon bridges...... that can be heated in a controlled fashion. The differential thermal response of the bridges with and without adsorbed explosive vapor shows unique and reproducible characteristics depending on the nature of the adsorbed explosives. The tunable heating rate method described here is capable of providing...... unique signals for subnanogram quantities of adsorbed explosives within 50 ms. (C) 2008 American Institute of Physics....

  10. SYNTHESIS OF SPHERICAL MACROPOROUS ADSORBENT BASED ON UREA—FORMALDEHYDE CONDENSED POLYMER

    Institute of Scientific and Technical Information of China (English)

    XUMingcheng; XUMancai; 等

    2000-01-01

    Spherical macroporous adsorbents with active sites capable of hydrogen bonding adsorption based on urea-formaldehyde condensed polymer were synthesized via reversed suspension polymerization.The properties of the obtained adsorbent were also investigated in detail.The results showed that the water permeability could be improved by adding hydroxyl-contatining organic compound moiety into the adsorbent.The specific surface area and average pore diameter of these adsorbents increaswed while the porosity first increased then decreased with the increase of the amount of the added hydroxyl-containing compound.

  11. Dynamic characteristics of helium adsorbents. Influence of the heat removal conditions

    Science.gov (United States)

    Shcherbachenko, R. I.; Grigor'ev, V. N.

    2008-06-01

    The static and dynamic characteristics of the adsorbent SKN-1K at 4.2K are investigated under conditions corresponding to the working conditions of adsorption pumps in dilution refrigerators. It is shown that gluing this adsorbent to the cooled surface leads to a substantial lowering of the pressure in the pump in the dynamic regime. On the basis of experimental data for the glued and free adsorbent an estimate is made of the hydrodynamic contribution to the pressure due to the resistance of the pores of the adsorbent. This estimate falls within the error of measurement.

  12. Investigations into Alternative Desorption Agents for Amidoxime-Based Polymeric Uranium Adsorbents

    Energy Technology Data Exchange (ETDEWEB)

    Gill, Gary A.; Kuo, Li-Jung; Strivens, Jonathan E.; Wood, Jordana R.; Wai, Chien; Pan, Horng-Bin

    2015-06-15

    Amidoxime-based polymeric braid adsorbents that can extract uranium (U) from seawater are being developed to provide a sustainable supply of fuel for nuclear reactors. A critical step in the development of the technology is to develop elution procedures to selectively remove U from the adsorbents and to do so in a manner that allows the adsorbent material to be reused. This study investigates use of high concentrations of bicarbonate along with targeted chelating agents as an alternative means to the mild acid elution procedures currently in use for selectively eluting uranium from amidoxime-based polymeric adsorbents.

  13. Investigations into Alternative Desorption Agents for Amidoxime-Based Polymeric Uranium Adsorbents

    Energy Technology Data Exchange (ETDEWEB)

    Gill, Gary A. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Kuo, Li-Jung [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Strivens, Jonathan E. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Wood, Jordana R. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Wai, Chien [LCW Supercritical Technologies, Inc., Seattle, WA (United States); Pan, Horng-Bin [Univ. of Idaho, Moscow, ID (United States)

    2015-06-01

    Amidoxime-based polymeric braid adsorbents that can extract uranium (U) from seawater are being developed to provide a sustainable supply of fuel for nuclear reactors. A critical step in the development of the technology is to develop elution procedures to selectively remove U from the adsorbents and to do so in a manner that allows the adsorbent material to be reused. This study investigates use of high concentrations of bicarbonate along with targeted chelating agents as an alternative means to the mild acid elution procedures currently in use for selectively eluting uranium from amidoxime-based polymeric adsorbents.

  14. Toward an effective adsorbent for polar pollutants: formaldehyde adsorption by activated carbon.

    Science.gov (United States)

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

    2013-09-15

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

  15. Photoluminescence Enhancement of Adsorbed Species on Si Nanoparticles.

    Science.gov (United States)

    Matsumoto, Taketoshi; Maeda, Masanori; Kobayashi, Hikaru

    2016-12-01

    We have fabricated Si nanoparticles from Si swarf using the beads milling method. The mode diameter of produced Si nanoparticles was between 4.8 and 5.2 nm. Si nanoparticles in hexane show photoluminescence (PL) spectra with peaks at 2.56, 2.73, 2.91, and 3.09 eV. The peaked PL spectra are attributed to the vibronic structure of adsorbed dimethylanthracene (DMA) impurity in hexane. The PL intensity of hexane with DMA increases by ~3000 times by adsorption on Si nanoparticles. The PL enhancement results from an increase in absorption probability of incident light by DMA caused by adsorption on the surface of Si nanoparticles.

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

    Science.gov (United States)

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

    2016-05-01

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

  17. Enhancing the reactivity of gold: Nanostructured Au(111) adsorbs CO

    Science.gov (United States)

    Hoffmann, F. M.; Hrbek, J.; Ma, S.; Park, J. B.; Rodriguez, J. A.; Stacchiola, D. J.; Senanayake, S. D.

    2016-08-01

    Low-coordinated sites are surface defects whose presence can transform a surface of inert or noble metal such as Au into an active catalyst. Starting with a well-ordered Au(111) surface we prepared by ion sputtering gold surfaces modified by pits, used microscopy (STM) for their structural characterization and CO spectroscopy (IRAS and NEXAFS) for probing reactivity of surface defects. In contrast to the Au(111) surface CO adsorbs readily on the pitted surfaces bonding to low-coordinated sites identified as step atoms forming {111} and {100} microfacets. Pitted nanostructured surfaces can serve as interesting and easily prepared models of catalytic surfaces with defined defects that offer an attractive alternative to vicinal surfaces or nanoparticles commonly employed in catalysis science.

  18. The adsorbed state of a thiol on palladium nanoparticles.

    Science.gov (United States)

    Rogers, Scott M; Dimitratos, Nikolaos; Jones, Wilm; Bowker, Michael; Kanaras, Antonios G; Wells, Peter P; Catlow, C Richard A; Parker, Stewart F

    2016-06-29

    In the present work, a combination of imaging, spectroscopic and computational methods shows that 1-dodecanethiol undergoes S-deprotonation to form 1-dodecanethiolate on the surface of palladium nanoparticles, which then self-assembles into a structure that shows a high degree of order. The alkyl chain is largely in the all-trans conformation, which occurs despite the small size of the nanoparticle, (mean diameter = 3.9 nm). Inelastic neutron scattering spectroscopy is readily able to characterise organic surface layers on nanoparticles; the nature of the material is irrelevant: whether the nanoparticle core is an oxide, a metal or a semiconductor makes no difference. Comparison to DFT calculations allows insights into the nature and conformation of the adsorbed layer. PMID:27087637

  19. Application of Henry's Law for Binding Energies of Adsorbed Hydrogen

    Science.gov (United States)

    Gillespie, Andrew; Dohnke, Elmar; Stalla, David; Sweany, Mark; Pfeifer, Peter

    2015-03-01

    The method of isosteres is the simplest method used to calculate the differential enthalpy of adsorption. However, it is incredibly sensitive to the choice of model and respective fitting parameters. For a set of isotherms measured on a specific sample, most models converge upon a similar value at high coverage, but are inconsistent in the low pressure regime. In this talk, we investigate the application of various models for localized and mobile adsorption at low pressures in order to obtain binding energy of hydrogen to the adsorbent surface. Henry's Law analysis of the Langmuir Model of adsorption yield binding energies in excellent agreement with those obtained from the Clausius Clapeyron relation. Work supported by DOE-EERE, Award No. DE-FG36-08GO18142.

  20. Challenge to high-activity-level water treatment by adsorbents

    International Nuclear Information System (INIS)

    There are over 280,000 tonnes of contaminated water in the damaged Fukushima Daiichi Nuclear Plant site in various tanks and barges and a large amount of contaminated water is now producing at the rate of several tonnes/day owing to inevitable cooling of the reactor cores. SARRY (Simplified Active Water Retrieve and Recovery System) and ALPS (Advanced Liquid Processing System) are installed to remove Cs and multi-elements respectively utilizing ion exchangers (zeolite, crystalline silicon titanate, and metal ferrocyanides) from contaminated water. The author continues efforts to find effective and selective adsorbents for Cs and Sr by measuring partition data, adsorption isotherms and adsorption rate referring with chemical structure elucidated from X-ray diffraction and SEM techniques. The obtained data are presented. (S. Ohno)

  1. CALCULATION OF THE YOUNG'S MODULUS OF AN ADSORBED POLYMER LAYER

    Institute of Scientific and Technical Information of China (English)

    Rüdiger Stark; Michael Kappl; Hans-Jürgen Butt

    2007-01-01

    Polymer layers adsorbed to a surface or in a confined environment often change their mechanical properties. There is even the possibility of solidification of the confined layer. To judge the stiffness of such a layer, we used the Hertz model to calculate the Young's modulus of the polymer layer in the confinement of AFM experiments with silicon nitride tip with a radius of curvature of R ≈ 50 nm and a glass sphere attached to the cantilever R = 5 μm. Since there is no visible indentation of the layer in the AFM experiments, the layer is either penetrated very easily, or the indentation is too small to be seen in a force curve. The latter would be the case for a polymer layer with a Young's modulus above 4×108 Pa in case of an experiment with a silicon nitride tip and 4×105 Pa in case of a glass sphere.

  2. Spontaneous Symmetry Breaking in Metal Adsorbed Graphene Sheets

    CERN Document Server

    Jalbout, A F

    2012-01-01

    Graphene has received a great deal of attention and this has more recently extended to boron nitride sheets (BNS) with a similar structure. Both have hexagonal lattices and it is only the alternation of atoms in boron nitride, which changes the symmetry structure. This difference can for example be seen in the mean field equations, which for the corners of the Brillouin Zone are Dirac equations. For the case of graphene (equal atoms) we have the equation for massless particles, while for Boron Nitride has a finite gap and is more near a Dirac equation with mass near this gap.. Carbon structures in general and in particular also graphene can adsorb electron donors, such as alkaline atoms or molecules with a dipole moment. Typically these atoms and the dipoles can only attach in the sense to donate electron density. Some results for small sheet like structures are available.

  3. Adsorbent comparisons for anesthetic gas capture in hospital air emissions.

    Science.gov (United States)

    Mehrata, Mina; Moralejo, Carol; Anderson, William A

    2016-08-23

    For the development of emission control strategies, activated carbon, zeolite, molecular sieves, and a silica gel were tested for adsorption of the newer anesthetic gases isoflurane, sevoflurane, and desflurane from air. The activated carbon Norit GCA 48 was selected for the best performance, and adsorption isotherms at room temperature were developed for the three anesthetics. Equilibrium capacities for this carbon were in the range of 500 to 1,000 mg g(-1) for these anesthetics at partial pressures ranging from 5 to 45 Torr, with the most volatile compound (desflurane) showing the least favorable adsorption. Activated carbons are therefore suggested for use as effective adsorbents in emission control of these anesthetic gases from hospitals. PMID:27222158

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

    Directory of Open Access Journals (Sweden)

    Yuan Lu

    2016-05-01

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

  5. Evaluation of {sup 131}I retention in several adsorbers

    Energy Technology Data Exchange (ETDEWEB)

    Catanoso, Marcela F.; Osso Junior, Joao Alberto, E-mail: marcela.forli@gmail.co, E-mail: jaosso@ipen.b [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil). Diretoria de Radiofarmacia

    2011-07-01

    Several iodine radioisotopes are used in nuclear medicine for treatment and diagnostic purposes. The radioisotope {sup 131}I is used both in diagnosis and therapy due to its physical characteristics of decay by {beta}{sup -} and its {gamma}-ray emissions suitable for diagnosis. It is routinely produced at IPEN through the irradiation of TeO{sub 2} targets in the IEA-R1m nuclear reactor. After the irradiation, the {sup 131}I is separated by dry distillation, where the targets are put in an oven, heated at 760 deg C for 2 hours and the {sup 131}I, volatile, is carried by an O{sub 2} gas stream. The aim of this work was to evaluate the retention and elution of {sup 131}I samples produced at IPEN in several adsorbers as part of a project aiming the purification of these radioisotopes, allowing the labeling of biomolecules. Samples of {sup 131}I were used for retention and elution studies with the following adsorbers: commercial cartridges, anionic resin columns and cationic resin column. The results showed that Ag cartridges and anionic resins Dowex 1X8, Dowex 3 and IRA 400 had a great iodine retention but no elution after using specific eluents. The QMA light, acid alumina, neutral alumina and cationic resin Dowex 50WX4 showed high retention and elution and QMA plus and cationic resin Dowex 50WX8 and Dowex 50WX12 had a good retention but lower elution. Regarding to the better retention and elution, Ag cartridges and resins showed a higher percentage of iodine retention but lower elution yield and QMA light, acid and neutral alumina cartridges showed better results. (author)

  6. Controlling SO2 by Using Low Cost Adsorbents

    Directory of Open Access Journals (Sweden)

    Nenavath Gandhi

    2013-01-01

    Full Text Available Sulphur oxides are formed during high temperature combustion processes from the oxidation of sulphur in the air. The principal source of sulphur oxides is sulphur oxide (SO and sulphur dioxide (SO2, collectively known as SOx. SO and SO2 concentrations are therefore the highest in industrial area. Other important sources are power stations, heating plants, and industrial processes. Long-term exposure to sulphur dioxide may affect lung function, and that exposure to sulphur dioxide enhances the response to allergens in sensitized individuals. The feasibility of using waste materials as adsorbent for air pollutant SOx was evaluated in the present study. The experiments were carried out in laboratory on certain waste materials like Neem leaf powder, orange peel powder, custard apple leaf powder, Horse gram seed powder, Ragi seed powder, mango bark dust, mixed algae, and Neem bark dust. The experimental investigations were carried out by traditional adsorption studies, and they showed that all substances had certain capacity to adsorb SOx from aqueous solution of SOx. The order of adsorption by different low cost materials is Mango bark dust > Orange peel powder >Custard apple leaf powder> Neem leaf powder> Horse gram seed powder> Ragi seed powder> Neem bark powder, mixed algae by 98%>95%>88%>82%>80%>78%>77%>74%, respectively. At lower concentration the adsorption is more compared to higher concentration. It is found that the adsorption increases with an increase in surface area.DOI: http://dx.doi.org/10.5755/j01.erem.62.4.1947

  7. Evaluation of 131I retention in several adsorbers

    International Nuclear Information System (INIS)

    Several iodine radioisotopes are used in nuclear medicine for treatment and diagnostic purposes. The radioisotope 131I is used both in diagnosis and therapy due to its physical characteristics of decay by β- and its γ-ray emissions suitable for diagnosis. It is routinely produced at IPEN through the irradiation of TeO2 targets in the IEA-R1m nuclear reactor. After the irradiation, the 131I is separated by dry distillation, where the targets are put in an oven, heated at 760 deg C for 2 hours and the 131I, volatile, is carried by an O2 gas stream. The aim of this work was to evaluate the retention and elution of 131I samples produced at IPEN in several adsorbers as part of a project aiming the purification of these radioisotopes, allowing the labeling of biomolecules. Samples of 131I were used for retention and elution studies with the following adsorbers: commercial cartridges, anionic resin columns and cationic resin column. The results showed that Ag cartridges and anionic resins Dowex 1X8, Dowex 3 and IRA 400 had a great iodine retention but no elution after using specific eluents. The QMA light, acid alumina, neutral alumina and cationic resin Dowex 50WX4 showed high retention and elution and QMA plus and cationic resin Dowex 50WX8 and Dowex 50WX12 had a good retention but lower elution. Regarding to the better retention and elution, Ag cartridges and resins showed a higher percentage of iodine retention but lower elution yield and QMA light, acid and neutral alumina cartridges showed better results. (author)

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

    Energy Technology Data Exchange (ETDEWEB)

    Awual, Md. Rabiul, E-mail: awual.rabiul@jaea.go.jp [Actinide Coordination Chemistry Group, Quantum Beam Science Centre (QuBS), Japan Atomic Energy Agency (SPring-8), Hyogo 679-5148 (Japan); Yaita, Tsuyoshi [Actinide Coordination Chemistry Group, Quantum Beam Science Centre (QuBS), Japan Atomic Energy Agency (SPring-8), Hyogo 679-5148 (Japan); Taguchi, Tomitsugu [Nano-Structure Synthesis Research Group, Quantum Beam Science Centre (QuBS), Japan Atomic Energy Agency, Tokai-mura, Ibaraki-ken 319-1195 (Japan); Shiwaku, Hideaki; Suzuki, Shinichi; Okamoto, Yoshihiro [Actinide Coordination Chemistry Group, Quantum Beam Science Centre (QuBS), Japan Atomic Energy Agency (SPring-8), Hyogo 679-5148 (Japan)

    2014-08-15

    Graphical abstract: - Highlights: • DB24C8 crown ether was functionalized for preparation of conjugate adsorbent. • Radioactive {sup 137}Cs can be selectively removed by the conjugate adsorbent. • Adsorbent can effectively capture Cs even in the presence of a high amount Na and K. • Adsorbent is reversible and able to be reused without significant deterioration. - Abstract: Conjugate materials can provide chemical functionality, enabling an assembly of the ligand complexation ability to metal ions that are important for applications, such as separation and removal devices. In this study, we developed ligand immobilized conjugate adsorbent for selective cesium (Cs) removal from wastewater. The adsorbent was synthesized by direct immobilization of dibenzo-24-crown-8 ether onto inorganic mesoporous silica. The effective parameters such as solution pH, contact time, initial Cs concentration and ionic strength of Na and K ion concentrations were evaluated and optimized systematically. This adsorbent was exhibited the high surface area-to-volume ratios and uniformly shaped pores in case cavities, and its active sites kept open functionality to taking up Cs. The obtained results revealed that adsorbent had higher selectivity toward Cs even in the presence of a high concentration of Na and K and this is probably due to the Cs–π interaction of the benzene ring. The proposed adsorbent was successfully applied for radioactive Cs removal to be used as the potential candidate in Fukushima nuclear wastewater treatment. The adsorbed Cs was eluted with suitable eluent and simultaneously regenerated into the initial form for the next removal operation after rinsing with water. The adsorbent retained functionality despite several cycles during sorption-elution-regeneration operations.

  9. Adsorbate-adsorbate interactions and chemisorption at different coverage studied by accurate {\\em ab initio} calculations: CO on transition metal surfaces

    OpenAIRE

    Mason, Sara E.; Grinberg, Ilya; Rappe, Andrew M.

    2005-01-01

    We use density functional theory (DFT) with the generalized gradient approximation (GGA) and our first-principles extrapolation method for accurate chemisorption energies {[Mason {\\em et al.}, Phys. Rev. B {\\bf 69}, 161401R (2004)]} to calculate the chemisorption energy for CO on a variety of transition metal surfaces for various adsorbate densities and patterns. We identify adsorbate through-space repulsion, bonding competition, and substrate-mediated electron delocalization as key factors d...

  10. Investigations on the adsorbents for uremic middle molecular toxins (II) —Influences of crosslinking agent chain length on the adsorption capacities of crosslinked chitosan adsorbents

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    Chitosan resins, which clinically served as adsorbents in hemoperfusion therapy, were prepared with reversed-phase suspension methodology using three differently structured crosslinking agents, methanal, glyoxal and glutaraldehyde. And the glyoxal and glutaraldehyde crosslinked chitosan resins were reduced with NaBH4 afterwards. By analyzing the results from FTIR and SEM, it was found that the reduction treatment to the adsorbents efficiently improved the chemical stability of these chitosan resins, and the shifts in crosslinking agents exerted influences over the morphologies of the adsorbents obviously. After being put to use in the adsorption tests upon some model uremic middle molecular toxins and BSA in vitro, all three adsorbents demon- strated a fairly realistic adsorption capability to the model toxins but little to BSA. And the adsorp- tion process reached the equilibrium in a clinically qualified short time. But the adsorption capaci- ties of these adsorbents to the model toxins were quite different. It had been found that with the growing of fatty chain length of crosslinking agent, these adsorbents showed a gradually increased adsorption capacity to the model toxins, and the glutaraldehyde crosslinked chitosan resin be- haved best.

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

    International Nuclear Information System (INIS)

    In order to use as adsorbent for removal of the soluble corrosion products, mainly Co60 under PWR reactor coolant conditions (300 deg C, 160 kg/cm2), stable ZrO2 adsorbent was prepared using sol-gel process from zirconyl nitrate, AlO adsorbent was prepared by hydrolysis of aluminum isopropoxide, and titanium tetraisopropoxide, respectively. The prepared adsorbents were calcined at various temperature and analyzed by physical properties and the Co2+ adsorption capacity. And it was shown that the Co2+ adsorption capacity of the TiO2-Al2O3 adsorbents were found to have larger than that of ZrO2 and Al2O3 adsorbents in high-temperature water. ZrO2, Al2O3 and TiO2-Al2O3 adsorbents were found to be suitable high-temperature adsorbents for the removal of dissolved corrosion products, mainly Co in PWR reactor coolant conditions. 15 tabs., 51 figs., 55 refs. (Author)

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

    Science.gov (United States)

    Lata, Sneh; Samadder, S R

    2016-01-15

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

  13. Scandium-Triflate/Metal-Organic Frameworks: Remarkable Adsorbents for Desulfurization and Denitrogenation.

    Science.gov (United States)

    Khan, Nazmul Abedin; Jhung, Sung Hwa

    2015-12-01

    Scandium-triflate (Sc(OTf)3) was introduced for the first time on metal-organic frameworks (MOFs), to utilize acidic Sc(OTf)3 for adsorptive desulfurization and denitrogenation of fuel containing benzothiophene (BT), dibenzothiophene (DBT), quinoline (QUI), and indole (IND). A remarkable improvement in the adsorption capacity (about 65% based on the weight of adsorbents; 90% based on the surface area of the adsorbents) was observed with the Sc(OTf)3/MOFs as compared to the virgin MOFs for the adsorption of BT from liquid fuel. The basic QUI was also adsorbed preferentially onto the acidic Sc(OTf)3/MOFs. However, nonsupported Sc(OTf)3 showed negligible adsorption capacities. The improved adsorptive performance for BT, DBT, and QUI might be derived from acid-base interactions between the acidic Sc(OTf)3 and basic adsorbates. On the other hand, the Sc(OTf)3, loaded on MOFs, reduced the adsorption capacity for neutral IND due to lack of interaction between the neutral adsorbate and acidic adsorbent and the reduced porosities of the modified adsorbents. The reusability of the adsorbents was found satisfactory up to the fourth run. On the basis of the result, it is suggested that metal-triflates, such as Sc(OTf)3, can be prospective materials for adsorptive desulfurization/denitrogenation of fuels when supported on porous materials such as MOFs. PMID:26575418

  14. Synergistic process design: Reducing drying energy consumption by optimal adsorbent selection

    NARCIS (Netherlands)

    Atuonwu, J.C.; Straten, van G.; Deventer, van H.C.; Boxtel, van A.J.B.

    2013-01-01

    This work analyzes the synergy between two complementary unit operations - adsorbent dehumidification and drying - and presents a mixed integer nonlinear programming approach to optimize energy performance in a two-stage system. Combined with active constraint analysis, the adsorbent properties that

  15. Structure and dynamics of egg white ovalbumin adsorbed at the air/water interface

    NARCIS (Netherlands)

    Kudryashova, E.V.; Meinders, M.B.J.; Visser, A.J.W.G.; Hoek, A. van; Jongh, H.H.J. de

    2003-01-01

    The molecular properties of egg white ovalbumin adsorbed at the air/water interface were studied using infrared reflection absorption spectroscopy (IRRAS) and time-resolved fluorescence anisotropy (TRFA) techniques. Ovalbumin adsorbed at the air/ water interface adopts a characteristic partially unf

  16. Potentiality of agricultural adsorbent for the sequestering of metal ions from wastewater

    Directory of Open Access Journals (Sweden)

    P.C. Emenike

    2016-12-01

    Full Text Available The expensive nature of metal ions detoxification from wastewater have restricted the use of conventional treatment technologies. Cheap, alternative measures have been adopted to eliminate metal contamination, and adsorptions using agricultural adsorbents seem to be the way forward. The use of agricultural adsorbents for cadmium (II, copper (II and lead (II ion removal has gained more interest in literature due to the level of contamination in water bodies. This review shed lights on the removal proficiency of various low–cost agricultural adsorbent for the elimination of cadmium (II, copper (II and lead (II ions, considering performance, surface modification, equilibrium adsorptive studies, kinetic characteristics, coefficient of correlation (R2 and reuse. Furthermore, these agricultural adsorbents have displayed better performance when rivaled with commercial/conventional adsorbent. Observations from different adsorptive capacities presented owe their performance to surface area improvement/modification, pH of the adsorbent, ionic potential of the solution, initial concentration and elemental component of the adsorbent. However, gaps have been identified to improve applicability, sorption performance, economic viability, optimization, and commercialization of suitable agricultural adsorbents.

  17. Electronically driven adsorbate excitation mechanism in femtosecond-pulse laser desorption

    DEFF Research Database (Denmark)

    Brandbyge, Mads; Hedegård, Per; Heinz, T. F.;

    1995-01-01

    Femtosecond-pulse laser desorption is a process in which desorption is driven by a subpicosecond temperature pulse of order 5000 K in the substrate-adsorbate electron system, whose energy is transferred into the adsorbate center-of-mass degrees of freedom by a direct coupling mechanism. We presen...

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

    DEFF Research Database (Denmark)

    Lai, Xuxin; Zheng, Yiwu; Jacobsen, Susanne;

    2008-01-01

    Analysis of aluminum hydroxide based vaccines is difficult after antigen adsorption. Adsorbed protein is often assessed by measuring residual unadsorbed protein for quality control. A new method for the direct determination of adsorbed protein concentration in suspension using near-infrared (NIR...... in vaccine production as a method for quality control and quality assurance....

  19. Poly(vinylpyridine) adsorbent for the removal of SIPA from its aqueous solution

    Institute of Scientific and Technical Information of China (English)

    Wei Hua Tao; Ai Min Li; Chao Long; Hong Ming Qian

    2009-01-01

    Poly(vinylpyridine) WH-225 resin was prepared and characterized.Compared with the commercial hypercrosslinked adsorbent NDA-100 and macroporous adsorbent XAD-4 resins,the newly synthesized poly(vinylpyridine) WH-225 resin exhibited the highest adsorption capacity toward SIPA from aqueous solution.

  20. Adsorbate-metal bond effect on empirical determination of surface plasmon penetration depth.

    Science.gov (United States)

    Kegel, Laurel L; Menegazzo, Nicola; Booksh, Karl S

    2013-05-21

    The penetration depth of surface plasmons is commonly determined empirically from the observed response for adsorbate loading on gold surface plasmon resonance (SPR) substrates. However, changes in the SPR spectrum may originate from both changes in the effective refractive index near the metal surface and changes in the metal permittivity following covalent binding of the adsorbate layer. Herein, the significance of incorporating an additional adsorbate-metal bonding effect in the calculation is demonstrated in theory and in practice. The bonding effect is determined from the nonzero intercept of a SPR shift versus adsorbate thickness calibration and incorporated into the calculation of penetration depth at various excitation wavelengths. Determinations of plasmon penetration depth with and without the bonding response for alkanethiolate-gold are compared and are shown to be significantly different for a thiol monolayer adsorbate system. Additionally, plasmon penetration depth evaluated with bonding effect compensation shows greater consistency over different adsorbate thicknesses and better agreement with theory derived from Maxwell's equation, particularly for adsorbate thicknesses that are much smaller (<5%) than the plasmon penetration depth. The method is also extended to a more practically applicable polyelectrolyte multilayer adsorbate system. PMID:23566015

  1. SHIFTS IN ADSORBATE VIBRATIONAL FREQUENCIES DUE TO INTERNAL ELECTRIC-FIELDS

    NARCIS (Netherlands)

    BAGUS, PS; ILLAS, F

    1994-01-01

    A new physical mechanism is proposed to explain the shifts in vibrational frequency of negatively adsorbed species on a metal surface. Ab initio cluster model calculations for NO adsorbed Dn Ag(111) in two different orientations, N-down and O-down, suggest that the low-coverage HREELS peak appearing

  2. Sorption of methylene blue on treated agricultural adsorbents: equilibrium and kinetic studies

    Science.gov (United States)

    Tiwari, D. P.; Singh, S. K.; Sharma, Neetu

    2015-03-01

    Agricultural adsorbents are reported to have a remarkable performance for adsorption of dyes. In the present study, formaldehyde and sulphuric acid treated two agricultural adsorbents; potato peel and neem bark are used to adsorb methylene blue. On the whole, the acid-treated adsorbents are investigated to have high sorption efficiency compared to HCHO treated adsorbents. The percentage removal efficiency of H2SO4 treated potato peel (APP) increases considerably high from 75 to 100 % with increase in adsorbent dose, whereas the removal efficiency of H2SO4 treated neem bark (ANB) is found to be 98 % after adding the first dose only. The monolayer sorption behaviour of HCHO treated potato peel (PP) and APP is well defined by Langmuir, whereas the chemisorptions behaviour of HCHO treated neem bark (NB) and ANB is suggested by Temkin's isotherm model. The maximum adsorption capacity measured is highest in ANB followed by NB, PP and APP with the values of 1000, 90, 47.62 and 40.0 mg/g, respectively. The pseudo-second-order kinetic model fitted well with the observed data of all the four adsorbents. The results obtained reveal that NB and ANB both are good adsorbents compared to PP and APP.

  3. Solid-state conversion of fly ash to effective adsorbents for Cu removal from wastewater.

    Science.gov (United States)

    Wang, Shaobin; Li, Lin; Zhu, Z H

    2007-01-10

    Solid-state conversion of fly ash to an amorphous aluminosilicate adsorbent (geopolymer) has been investigated under different conditions and the synthesised material has been tested for Cu2+ removal from aqueous solution. It has been found that higher reaction temperature and Na:FA ratio will make the adsorbents achieving higher removal efficiency. The adsorbent loading and Cu2+ initial concentration will also affect the removal efficiency while the adsorption capacity exhibits similarly at 30-40 degrees C. The adsorption capacity of the synthesised adsorbent shows much higher value than fly ash and natural zeolite. The capacity is 0.1, 3.5 and 92 mg/g, for fly ash, natural zeolite, and FA derived adsorbent, respectively. The kinetic studies indicate that the adsorption can be fitted by the second-order kinetic model. Langmuir and Freundlich isotherms also can fit to the adsorption isotherm.

  4. Preparation of ferric-activated sludge-based adsorbent from biological sludge for tetracycline removal.

    Science.gov (United States)

    Yang, Xin; Xu, Guoren; Yu, Huarong; Zhang, Zhao

    2016-07-01

    Ferric activation was novelly used to produce sludge-based adsorbent (SBA) from biological sludge through pyrolysis, and the adsorbents were applied to remove tetracycline from aqueous solution. The pyrolysis temperature and mass ratio (activator/dried sludge) greatly influenced the surface area and pore characteristics of SBA. Ferric activation could promote the porous structure development of adsorbents, and the optimum preparation conditions were pyrolysis temperature 750°C and mass ratio (activator/dried sludge) 0.5. In batch experiments, ferric-activated SBA showed a higher adsorption capacity for tetracycline than non-activated SBA, because the enhanced mesoporous structure favored the diffusion of tetracycline into the pores, the iron oxides and oxygen-containing functional groups in the adsorbents captured tetracycline by surface complexation. The results indicate that ferric activation is an effective approach for preparing adsorbents from biological sludge to remove tetracycline, providing a potential option for waste resource recovery. PMID:27038265

  5. Removal of murexide (dye) from aqueous media using rice husk as an adsorbent

    International Nuclear Information System (INIS)

    The use of low-cost and eco friendly adsorbent was investigated as an ideal alternative to the current expensive methods of removing dyes from wastewater. Rice husk was used as an adsorbent for the removal of Murexide from aqueous solutions. The rate of adsorption was investigated under various parameters such as size of adsorbent, contact time of solution with adsorbent, temperature, pH, adsorbent dose and stirring speed for the removal of this dye. Langmuir isotherm was also applied to evaluate maximum adsorption capacity of rice husk for Murexide. On the basis of results obtained, it is proposed that rice husk can be effectively used for the elimination of Murexide from waste water. (author)

  6. Electric field cancellation on quartz by Rb adsorbate-induced negative electron affinity

    Science.gov (United States)

    Shaffer, James

    2016-05-01

    We investigate the (0001) surface of single crystal quartz with a submonolayer of Rb adsorbates. Using Rydberg atom electromagnetically induced transparency, we investigate the electric fields resulting from Rb adsorbed on the quartz surface, and measure the activation energy of the Rb adsorbates. We show that the adsorbed Rb induces a negative electron affinity (NEA) on the quartz surface. The NEA surface allows low energy electrons to bind to the surface and cancel the electric field from the Rb adsorbates. Our results are important for integrating Rydberg atoms into hybrid quantum systems and the fundamental study of atom-surface interactions, as well as applications for electrons bound to a 2D surface. This work was supported by the DARPA Quasar program by a Grant through ARO (60181-PH-DRP) and the AFOSR (FA9550-12-1-0282),.

  7. Estimation of the Isotherms of Phenol on Activated Carbons and Polymeric Adsorbents under Supercritical Condition

    Institute of Scientific and Technical Information of China (English)

    奚红霞; 谢兰英; 李祥斌; 李忠

    2003-01-01

    A method named as "volume-expanding and pressure-reducing adsorption" is proposed. It can be used to measure the isotherms under supercritical condition. The adsorption isotherms of phenol on activated carbons and polymeric adsorbents are estimated and compared respectively for the systems of "phenol-activated carbon-supercritical fluid CO2" and "phenol-polymeric adsorbent-supercritical fluid CO2". The results show that the amount of phenol adsorbed on the activated carbons and the polymeric adsorbents under the supercritical condition is much less than that under the general condition, which can be utilized to develop a technology regenerating the activated carbon with supercritical fluid. Moreover, the effects of ethyl alcohol, used as the third component, on the isotherms of phenol on the activated carbons and polymeric adsorbents under the supercritical condition are also investigated.

  8. Thermodynamic formalism of water uptakes on solid porous adsorbents for adsorption cooling applications

    Energy Technology Data Exchange (ETDEWEB)

    Sun, Baichuan; Chakraborty, Anutosh, E-mail: AChakraborty@ntu.edu.sg [School of Mechanical and Aerospace Engineering, Nanyang Technological University, 50 Nanyang Avenue, Singapore 639798 (Singapore)

    2014-05-19

    This Letter presents a thermodynamic formulation to calculate the amount of water vapor uptakes on various adsorbents such as zeolites, metal organic frameworks, and silica gel for the development of an advanced adsorption chiller. This formalism is developed from the rigor of the partition distribution function of each water vapor adsorptive site on adsorbents and the condensation approximation of adsorptive water molecules and is validated with experimental data. An interesting and useful finding has been established that the proposed model is thermodynamically connected with the pore structures of adsorbent materials, and the water vapor uptake highly depends on the isosteric heat of adsorption at zero surface coverage and the adsorptive sites of the adsorbent materials. Employing the proposed model, the thermodynamic trends of water vapor uptakes on various adsorbents can be estimated.

  9. Thermodynamic formalism of water uptakes on solid porous adsorbents for adsorption cooling applications

    Science.gov (United States)

    Sun, Baichuan; Chakraborty, Anutosh

    2014-05-01

    This Letter presents a thermodynamic formulation to calculate the amount of water vapor uptakes on various adsorbents such as zeolites, metal organic frameworks, and silica gel for the development of an advanced adsorption chiller. This formalism is developed from the rigor of the partition distribution function of each water vapor adsorptive site on adsorbents and the condensation approximation of adsorptive water molecules and is validated with experimental data. An interesting and useful finding has been established that the proposed model is thermodynamically connected with the pore structures of adsorbent materials, and the water vapor uptake highly depends on the isosteric heat of adsorption at zero surface coverage and the adsorptive sites of the adsorbent materials. Employing the proposed model, the thermodynamic trends of water vapor uptakes on various adsorbents can be estimated.

  10. 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.

  11. Poly(ethylene oxide) Mushrooms Adsorbed at Silica-Ionic Liquid Interfaces Reduce Friction.

    Science.gov (United States)

    Sweeney, James; Webber, Grant B; Atkin, Rob

    2016-03-01

    The adsorbed layer conformation and lubricity of 35, 100, and 300 kDa PEO adsorbed to ionic liquid (IL)-silica interfaces from 0.01 wt % solutions have been investigated using colloid probe atomic force microscopy. The ILs used were propylammonium nitrate (PAN) and 1-butyl-3-methylimidazolium tetrafluoroborate ([BMIM][BF4]), which are protic and aprotic ILs, respectively. Normal force curves reveal steric interactions consistent with adsorbed polymer layers which are best fit using the mushroom model. Friction measurements show that the adsorbed polymer layer markedly reduces friction compared to surfaces sliding in the pure ILs and that lubricity increases with polymer length. When polymer is adsorbed to the sliding surfaces, friction is controlled by the creation and disruption of intermolecular interactions between entangled chains and the dragging of polymer chains through the interpenetration region. These experiments show that added polymer can reduce friction while maintaining the useful properties of ILs as lubricants. PMID:26844589

  12. Effective thermal conductivity of expanded graphite-CaCl2 composite adsorbent for chemical adsorption chillers

    International Nuclear Information System (INIS)

    This paper presents experimental data on the thermal conductivity for three types of adsorbent, namely, pure CaCl2 powder, simple composite adsorbent and consolidated composite adsorbent. The thermal conductivities were measured by the 'hot wire method' at a fixed pressure and temperature under an ammonia atmosphere. Effective thermal conductivities of the expanded graphite-CaCl2 . nNH3 (n = 2, 4, 8) consolidated composite adsorbent are in the range of 7.05-9.2 W m-1 K-1, which are significant higher values than those of the powders bed of 0.3-0.4 W m-1 K-1. The obtained results show that the composite adsorbent thermal conductivity λ has a strong dependence on the bulk density, the weight fraction of expanded graphite and the ammoniated state of CaCl2

  13. SYNERGISTIC INTERACTIONS ON PHENOL ADSORPTION FROM AQUEOUS SOLUTIONS BY POLYMERIC ADSORBENTS

    Institute of Scientific and Technical Information of China (English)

    Wei-ming Zhang; Jin-long Chen; Bing-cai Pan; Quan-xing Zhang; Bo Zhang; Fan Wang

    2005-01-01

    In this paper, the adsorption behaviors of phenol on polymeric adsorbents (Amberlite XAD4, NDA101, and D301)were investigated in batch system at 293, 303, and 313 K, respectively. As the results shown, the adsorption isotherms of phenol on all adsorbents can be well fitted by Langmuir and Freundlich equations, which indicate a favorable and exothermic process. The adsorption capacity on a newly developed aminated adsorbent, NDA101, on which adsorption could be achieved by both hydrogen bonding interaction and π-π interaction, are higher than that on a weak base adsorbent, D301, on which adsorption could be achieved by hydrogen bonding interaction only, and on a nonpolar adsorbent, XAD4, on which adsorption could be achieved by π-π interaction only. The results of this paper indicate that the synergistic effect of some weak interactions, which occur simultaneously would contribute more to the adsorption than that occur individually.

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

    Science.gov (United States)

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

    2015-10-01

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

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

    Institute of Scientific and Technical Information of China (English)

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

    2011-01-01

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

  16. Development of carbon dioxide adsorbent from rice husk char

    Science.gov (United States)

    Abang, S.; Janaun, J.; Anisuzzaman, S. M.; Ikhwan, F. S.

    2016-06-01

    This study was mainly concerned about the development of carbon dioxide (CO2) adsorbent from rice husk (RH). Several chemical treatments were used to produce activated rice husk char (RHAC) from RH. Initially the RH was refluxed with 3M of sodium hydroxide (NaOH) solution, activation followed by using 0.5M of zinc chloride (ZnCl2) solution and finally acidic treatment by using 0.1M of hydrochloric acid (HCl). Then, the RHAC was functionalized by using 3-chloropropylamine hydrochloride (3-CPA) and noted as RHN. RHN samples were characterized with scanning electron microscopy (SEM), mercury intrusion porosimetry (MIP), fourier transform infrared spectroscopy (FTIR). Based on the SEM, the RHN sample had a large pore diameter compared to RH sample after being treated. Based on MIP data, the average pore diameter between RH and RHAC samples were increased significantly from 0.928 microns to 1.017 microns. The RHN sample also had higher total porosity (%) compared to RHAC and RH (58.45%, 47.82% and 45.57% respectively). The total specific surface area of the sample was much increasing from RHO to RHAC (29.17 m2/g and 62.94 m2/g respectively) and slightly being decreasing from RHAC to RHN (58.88 m2/g). FTIR result showed the present of weak band at 1587 cm-1 which demonstrating of the amine group present on the sample. The CO2 capture result showed that the decreasing of operating temperature can increase the breakthrough time of CO2 capture. On the contrary decreasing of CO2 gas flow rate can increase the breakthrough time of CO2 capture. The highest total amount of CO2 adsorbed was 25338.57 mg of CO2/g of RHN sample by using 100 mL/min of gas flow rate at 30oC. Based on adsorption isotherm analysis, the Freundlich isotherm was the best isotherm to describe the CO2 adsorption on the sample.

  17. Tunable magnetism in metal adsorbed fluorinated nanoporous graphene

    Science.gov (United States)

    Kumar, Pankaj; Sharma, Vinit; Reboredo, Fernando A.; Yang, Li-Ming; Pushpa, Raghani

    2016-01-01

    Developing nanostructures with tunable magnetic states is crucial for designing novel data storage and quantum information devices. Using density functional theory, we investigate the thermodynamic stability and magnetic properties of tungsten adsorbed tri-vacancy fluorinated (TVF) graphene. We demonstrate a strong structure-property relationship and its response to external stimuli via defect engineering in graphene-based materials. Complex interplay between defect states and the chemisorbed atom results in a large magnetic moment of 7 μB along with high in-plane magneto-crystalline anisotropy energy (MAE) of 17 meV. Under the influence of electric field, spin crossover effect accompanied by a change in the MAE is observed. The ascribed change in spin-configuration is caused by the modification of exchange coupling between defect states and a change in the occupation of d-orbitals of the metal complex. Our predictions open a promising way towards controlling the magnetic properties in graphene based spintronic and non-volatile memory devices. PMID:27554975

  18. Dietary bioavailability of Cu adsorbed to colloidal hydrous ferric oxide

    Science.gov (United States)

    Cain, Daniel J.; Croteau, Marie-Noële; Fuller, Christopher C.

    2013-01-01

    The dietary bioavailability of copper (Cu) adsorbed to synthetic colloidal hydrous ferric oxide (HFO) was evaluated from the assimilation of 65Cu by two benthic grazers, a gastropod and a larval mayfly. HFO was synthesized, labeled with 65Cu to achieve a Cu/Fe ratio comparable to that determined in naturally formed HFO, and then aged. The labeled colloids were mixed with a food source (the diatom Nitzschia palea) to yield dietary 65Cu concentrations ranging from 211 to 2204 nmol/g (dry weight). Animals were pulse fed the contaminated diet and assimilation of 65Cu from HFO was determined following 1–3 days of depuration. Mass transfer of 65Cu from HFO to the diatom was less than 1%, indicating that HFO was the source of 65Cu to the grazers. Estimates of assimilation efficiency indicated that the majority of Cu ingested as HFO was assimilated (values >70%), implying that colloidal HFO potentially represents a source of dietary Cu to benthic grazers, especially where there is active formation and infiltration of these particles into benthic substrates.

  19. Utilization of Rice Husk as Pb Adsorbent in Blood Cockles

    Science.gov (United States)

    Rohaeti, Eti; Permata Sari, Wenny; Batubara, Irmanida

    2016-01-01

    Water pollution by lead affects blood cockles, a potential source of food. The aim of this research is to compare rice husk (RH) and rice husk carbon (RHC) in reducing the concentration of lead in blood cockles. RH and RHC were activated with NaOH 1 M, and then the optimal conditions and maximum capacity were determined. This research showed that RH and RHC had maximum adsorbancy capacities of 28.7326 mg/g and 51.5464 mg/g at optimal condition. The optimal adsorption condition for RH in 100 ml Pb solution is 0.32 gram, pH 5, for 4 hours. The optimal adsorption condition for RHC in 100 ml Pb solution is 0.20 gram, pH 5, for 2 hours. Lead content in blood cockles from the north waters of Jakarta (1.9658 mg/kg) is beyond the threshold limit. Lead adsorption by RH and RHC could reduce lead content in blood cockles by about 40% and 31%, respectively.

  20. Tunable magnetism in metal adsorbed fluorinated nanoporous graphene.

    Science.gov (United States)

    Kumar, Pankaj; Sharma, Vinit; Reboredo, Fernando A; Yang, Li-Ming; Pushpa, Raghani

    2016-01-01

    Developing nanostructures with tunable magnetic states is crucial for designing novel data storage and quantum information devices. Using density functional theory, we investigate the thermodynamic stability and magnetic properties of tungsten adsorbed tri-vacancy fluorinated (TVF) graphene. We demonstrate a strong structure-property relationship and its response to external stimuli via defect engineering in graphene-based materials. Complex interplay between defect states and the chemisorbed atom results in a large magnetic moment of 7 μB along with high in-plane magneto-crystalline anisotropy energy (MAE) of 17 meV. Under the influence of electric field, spin crossover effect accompanied by a change in the MAE is observed. The ascribed change in spin-configuration is caused by the modification of exchange coupling between defect states and a change in the occupation of d-orbitals of the metal complex. Our predictions open a promising way towards controlling the magnetic properties in graphene based spintronic and non-volatile memory devices. PMID:27554975

  1. Raman fingerprint of doping due to metal adsorbates on graphene.

    Science.gov (United States)

    Iqbal, M W; Singh, Arun Kumar; Iqbal, M Z; Eom, Jonghwa

    2012-08-22

    The properties of single-layer graphene are strongly affected by metal adsorbates and clusters on graphene. Here, we study the effect of a thin layer of chromium (Cr) and titanium (Ti) metals on chemical vapor deposition (CVD)-grown graphene by using Raman spectroscopy and transport measurements. The Raman spectra and transport measurements show that both Cr and Ti metals affect the structure as well as the electronic properties of the CVD-grown graphene. The shift of peak frequencies, intensities and widths of the Raman bands are analyzed after the deposition of metal films of different thickness on CVD-grown graphene. The shifts in G and 2D peak positions indicate the doping effect of graphene by Cr and Ti metals. While p-type doping was observed for Cr-coated graphene, n-type doping was observed for Ti-coated graphene. The doping effect is also confirmed by measuring the gate voltage dependent resistivity of graphene. We have also found that annealing in Ar atmosphere induces a p-type doping effect on Cr- or Ti-coated CVD-grown graphene. PMID:22814217

  2. Raman fingerprint of doping due to metal adsorbates on graphene

    International Nuclear Information System (INIS)

    The properties of single-layer graphene are strongly affected by metal adsorbates and clusters on graphene. Here, we study the effect of a thin layer of chromium (Cr) and titanium (Ti) metals on chemical vapor deposition (CVD)-grown graphene by using Raman spectroscopy and transport measurements. The Raman spectra and transport measurements show that both Cr and Ti metals affect the structure as well as the electronic properties of the CVD-grown graphene. The shift of peak frequencies, intensities and widths of the Raman bands are analyzed after the deposition of metal films of different thickness on CVD-grown graphene. The shifts in G and 2D peak positions indicate the doping effect of graphene by Cr and Ti metals. While p-type doping was observed for Cr-coated graphene, n-type doping was observed for Ti-coated graphene. The doping effect is also confirmed by measuring the gate voltage dependent resistivity of graphene. We have also found that annealing in Ar atmosphere induces a p-type doping effect on Cr- or Ti-coated CVD-grown graphene. (paper)

  3. Tunable magnetism in metal adsorbed fluorinated nanoporous graphene

    Science.gov (United States)

    Kumar, Pankaj; Sharma, Vinit; Reboredo, Fernando A.; Yang, Li-Ming; Pushpa, Raghani

    2016-08-01

    Developing nanostructures with tunable magnetic states is crucial for designing novel data storage and quantum information devices. Using density functional theory, we investigate the thermodynamic stability and magnetic properties of tungsten adsorbed tri-vacancy fluorinated (TVF) graphene. We demonstrate a strong structure-property relationship and its response to external stimuli via defect engineering in graphene-based materials. Complex interplay between defect states and the chemisorbed atom results in a large magnetic moment of 7 μB along with high in-plane magneto-crystalline anisotropy energy (MAE) of 17 meV. Under the influence of electric field, spin crossover effect accompanied by a change in the MAE is observed. The ascribed change in spin-configuration is caused by the modification of exchange coupling between defect states and a change in the occupation of d-orbitals of the metal complex. Our predictions open a promising way towards controlling the magnetic properties in graphene based spintronic and non-volatile memory devices.

  4. Effects of ambient conditions on adsorbed surfactant and polymer monolayers

    International Nuclear Information System (INIS)

    The physical properties of surfactant-coated and polyelectrolyte-coated surfaces in adhesive contact in air have been studied using the surface forces apparatus technique. Various physisorbed monolayers with different head groups and chains (or polymer segments) were prepared both by adsorption form solution (self-assembly) and by the Langmuir-Blodgett deposition technique. The results show that many monolayer properties depend on the atmospheric conditions such as the relative humidity or presence of organic vapors and that these properties can further change when two monolayer-coated surfaces are brought into contact. These properties include monolayer composition and structure, thickness and compressibility, fluidity and phase state (i.e., whether solid, gel, or liquid), and the adhesion between two monolayer-coated surfaces. In addition, we find that both out-of-plane and in-plane (lateral) phase transitions can be induced in certain adsorbed monolayers when they are subjected to a compressive stress. The results provide new insights into molecular ordering and dynamics in physisorbed monolayers and how monolayers are affected when they are exposed to vapors or when they interact with other surfaces. 18 refs., 13 figs., 4 tabs

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

    Directory of Open Access Journals (Sweden)

    Haider M. Zwain

    2014-01-01

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

  6. Molecular separations with breathing metal-organic frameworks: modelling packed bed adsorbers.

    Science.gov (United States)

    Van Assche, Tom R C; Baron, Gino V; Denayer, Joeri F M

    2016-03-14

    Various metal-organic framework (MOFs) adsorbents show peculiar adsorption behaviour as they can adopt different crystal phases, each phase with its own adsorption characteristics. Besides external stimuli such as temperature or light, different species of guest adsorbate can trigger a transition (breathing) of the host structure at a different pressure. Such phase transitions also occur during dynamic separations on a packed bed of adsorbent, where the concentrations of the adsorbates vary throughout axial column distance and time. This work presents a general strategy to model the adsorption behavior of such phase changing adsorbents during column separations and focuses on remarkable model predictions for pure components and binary mixtures in diluted and non-diluted conditions. During binary breakthrough experiments, the behaviour of flexible adsorbents is quite complex. A succession of complete or even partial phase transformations (resulting in phase coexistence) can occur during the adsorption process. A variety of unusual breakthrough profiles is observed for diluted binary mixtures. Simulations reveal at least five types of breakthrough profiles to emerge. The occurrence of these cases can be rationalized by the hodograph technique, combined with the phase diagram of the adsorbent. The remarkable experimental breakthrough profiles observed for ortho-xylene/ethylbenzene (diluted) and CO2/CH4 (non-diluted) separation on the flexible MIL-53 framework can be rationalized by application of the proposed model strategy. PMID:26885972

  7. The Recovery of Used Palm Cooking Oil Using Bagasse as Adsorbent

    Directory of Open Access Journals (Sweden)

    Rizki Wannahari

    2012-01-01

    Full Text Available Problem statement: The use and reduce cooking oil is a common phenomena in our society. While some of this cooking oil is further refine most of it however and not subject to any filtration in the refining process medium such as carbon active, silica are commonly use. Approach: The used of bagasse as adsorbent is not common. This is odd especially when structural component of bagasse which is made up of carbon material is suitable as adsorbent and the fact that, adsorbent bagasse further reduce solid waste disposal and hence reducing one source of environmental pollution. Results: This study was undertaken to explore the possibility of using bagasse as adsorbent. Specifically, bagasse is being experimented to reduce the harmful content such as Free Fatty Acid (FFA and color density in used cooking oil. The variation of adsorbent weight and contact time are used in this research as parameters to determine the effective time and the amount of adsorbent that should be used in the oil refining process. From the experiment conducted, it can be established that bagasse when use as an adsorbent can reduce FFA to 82.14% which is lower the harmful limit. Conclusion/Recommendations: This result is obtained when using 7.5 gr of bagasse for 60 m contact time. Similarly, the color of oil is reduced to 75.67% which is significant and this is base on 10 gr of bagasse with 60 m of contact time.

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

    International Nuclear Information System (INIS)

    In this work, magnetic ordered mesoporous carbon adsorbent was synthesized using soft templating method to adsorb sulfur from model oil (dibenzothiophene in n-hexane). Through this research, pluronic F-127, resorcinol-formaldehyde and hydrated iron nitrate were respectively used as soft template, carbon source and iron source. The adsorbent was characterized by X-ray diffraction, nitrogen adsorption–desorption isotherm and transmission electron microscopy. Nitrogen adsorption–desorption measurement revealed the high surface area (810 m2 g−1), maxima pore size of 3.3 nm and large pore volume (1.01 cm3 g−1) of the synthesized sample. The adsorbent showed a maximum adsorption capacity of 111 mg dibenzothiophene g−1 of adsorbent. Sorption process was described by the pseudo-second-order rate equation and could be better fitted by the Freundlich model, showing the heterogeneous feature of the adsorption process. In addition, the adsorption capacity of regenerated adsorbent was 78.6% of the initial level, after five regeneration cycles. - Highlights: • Adsorptive desulfurization of model oil with magnetic ordered mesoporous carbon adsorbent, Fe-OMC, was studied. • Maximum adsorption capacity (qmax) of Fe-OMC for DBT was found to be 111.1 mg g−1. • Freundlich isotherm best represents the equilibrium adsorption data. • Rate of DBT adsorption process onto Fe-OMC is controlled by at least two steps

  9. Towards Understanding KOH Conditioning of Amidoxime-based Polymer Adsorbents for Sequestering Uranium from Seawater

    Energy Technology Data Exchange (ETDEWEB)

    Pan, Horng-Bin; Kuo, Li-Jung; Wood, Jordana R.; Strivens, Jonathan E.; Gill, Gary A.; Janke, C.; Wai, Chien M.

    2015-11-16

    Conditioning of polymer fiber adsorbents grafted with amidoxime and carboxylic acid groups is necessary to make the materials hydrophilic for sequestering uranium from seawater. Spectroscopic techniques were employed to study the effectiveness of the traditional KOH conditioning method (2.5% KOH at 80 oC) on recently developed high-surface-area amidoxime-based polymer fiber adsorbents developed at Oak Ridge National Laboratory. FTIR spectra reveal that the KOH conditioning process removes the proton from the carboxylic acids and also converts the amidoxime groups to carboxylate groups in the adsorbent. With prolonged KOH treatment (>1 hr) at 80 oC, physical damage to the adsorbent material occurs which can lead to a significant reduction in the adsorbent’s uranium adsorption capability in real seawater during extended exposure times (>21 days). The physical damage to the adsorbent can be minimized by lowering KOH conditioning temperature. For the high-surface-area amidoxime-based adsorbents, 20 min of conditioning in 2.5% KOH at 80 oC or 1 hr of conditioning in 2.5% KOH at 60 oC appears sufficient to achieve de-protonation of the carboxylic acid with minimal harmful effects to the adsorbent material. The use of NaOH instead of KOH can also reduce the cost of the base treatment process required for conditioning the amidoxime-based sorbents with minimal loss of adsorption capacity (≤ 7%).

  10. Regenerable adsorbent for removing ammonia evolved from anaerobic reaction of animal urine

    Institute of Scientific and Technical Information of China (English)

    CHOU Liang-hsing; TSAI Ru-in; CHANG Jen-ray; LEE Maw-tien

    2006-01-01

    The waste gas evolved fiom biodegradation of animal mine contains ammonia causing environmental concerns. A new and effective method for removing ammonia from such waste gas using reactive adsorption is presented. In the process, activated carbon impregnated with H2SO4(H2SO4/C) is employed. Ammonia in the waste gas reacts with H2SO4 on the adsorbent instantaneously and completely to form (NH4)2SO4. The H2SO4/C adsorbent is high in NH3 adsorption capacity and regenerable. The NH3 removal capacity of this regenerable adsorbent is more than 30 times that of the adsorbents used normally in the industry. The spent H2SO4/C is regenerated by flowing low-pressure steam through the adsorbent bed to remove the (NH4)2SO4 fiom the adsorbent. The regeneration by-product is concentrated (NH4)2SO4 solution, which is a perfect liquid fertilizer for local use. Re-soaking the activated carbon with H2SO4 solution rejuvenates the activity of the adsorbent. Thus the H2SO4/C can be reused repeatedly. In the mechanism of this reactive adsorption process, trace of H2O in the waste gas is a required, which lends itself to treating ammonia gas saturated with moisture from biodegradation of animal urìne.

  11. Performance evaluation of low cost adsorbents in reduction of COD in sugar industrial effluent.

    Science.gov (United States)

    Parande, Anand K; Sivashanmugam, A; Beulah, H; Palaniswamy, N

    2009-09-15

    Studies on reduction of chemical oxygen demand (COD) in effluent from sugar industry have been carried out by employing different absorbents optimizing various parameters, such as initial concentration of adsorbate, pH, adsorbent dosage and contact time. Experimental studies were carried out in batches using metakaolin, tamarind nut carbon and dates nut carbon as adsorbents by keeping initial adsorbent dosage at 1 g l(-1), agitation time over a range of 30-240 min, adsorbent dosage at 100-800 mg l(-1) by varying the pH range from 4 to 10. Characterization of there adsorbents were done using techniques such as Fourier transforms infra red spectroscopy (FTIR), X-ray diffraction (XRD) and scanning electron microscope (SEM). The experimental adsorption data fitted well to Langmuir and Freundlich adsorption isotherms. The isotherms of the adsorbents indicate appreciable adsorption capacity. Higher COD removal was observed at neutral pH conditions. Studies reveal that maximum reduction efficiency of COD takes place using metakaolin as an absorbent at a dosage of 500 mg l(-1) in a contact time of 180 min at pH 7 and it could be used as an efficient absorbent for treating sugar industrial effluent.

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

    KAUST Repository

    Li, Ang

    2016-01-01

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

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2015-09-15

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

  14. Adsorptive Removal of Dye from Industrial Effluents Using Natural Iraqi Palygorskite Clay as Low-Cost Adsorbent

    OpenAIRE

    Dakhil Nasir Taha; Isra'a Sadi Samaka; Luma Ahmed Mohammed

    2013-01-01

    Palygorskite clay has been investigated as low cost and ecofriendly adsorbent for the removal Basic Red 2(BR-2) from aqueous solution. Batch adsorption studies are carried out by observing effect of amount of adsorbent dose, contact time, pH, initial concentration of ( BR-2) and particle size of adsorbent on the adsorption capacity of the adsorbent were studied. Adsorption data fits the Langmuir and Freundlich adsorption isotherms. The calculated value of the Langmuir parameter for adsorption...

  15. A WATER-COMPATIBLE PHENOLIC HYDROXYL MODIFIED POLYSTYRENE AS AN ADSORBENT FOR ADSORBING PHENOLIC COMPOUNDS FROM AQUEOUS SOLUTIONS

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    A water-compatible phenolic hydroxyl modified polystyrene adsorbent (AM-1) foradsorbing and removing phenolic compounds from aqueous solutions was prepared by covalent bonding of phenolic hydroxyl groups to the surface of porous polystyrene-divinylbenzene beads, this resin can be used directly without wetting process. A comparison of the sorption properties of the new resin and Amberlite XAD-4 toward four phenolic compounds, phenol, p-cresol, p-chlorophenol,and p-nitrophenol was made. The capacities of equilibrium adsorption of AM-l for all four phenolic compounds increased around 20% over that of Amberlite XAD-4, which may be contributed to phenol hydroxyl group on the surface and the unusual pore distributior. At their dilute solution, the equilibrium adsorption capacities of AM-1 for phenol increased about 62% over that of Amberlite X4D-4, while equilibrium adsorption capacities of the other three phenolic compounds increased 4-35%, suggesting an advantage of AM-I over Amberlite XAD-4 in the collection of phenol.Freundlich isotherm equations and isosteric adsorption enthalpies for the four phenolic compounds indicate a physical adsorption process on the Amberlite XAD-4 and AM-I resins. Column studies for phenol show that AM-1 resin has excellent adsorption and desorption performance.

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

    Directory of Open Access Journals (Sweden)

    Daniel Schwantes

    2016-01-01

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

  17. Mesoporous carbon adsorbents from melamine-formaldehyde resin using nanocasting technique for CO2 adsorption.

    Science.gov (United States)

    Goel, Chitrakshi; Bhunia, Haripada; Bajpai, Pramod K

    2015-06-01

    Mesoporous carbon adsorbents, having high nitrogen content, were synthesized via nanocasting technique with melamine-formaldehyde resin as precursor and mesoporous silica as template. A series of adsorbents were prepared by varying the carbonization temperature from 400 to 700°C. Adsorbents were characterized thoroughly by nitrogen sorption, X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), thermogravimetric analysis (TGA), elemental (CHN) analysis, Fourier transform infrared (FTIR) spectroscopy and Boehm titration. Carbonization temperature controlled the properties of the synthesized adsorbents ranging from surface area to their nitrogen content, which play major role in their application as adsorbents for CO2 capture. The nanostructure of these materials was confirmed by XRD and TEM. Their nitrogen content decreased with an increase in carbonization temperature while other properties like surface area, pore volume, thermal stability and surface basicity increased with the carbonization temperature. These materials were evaluated for CO2 adsorption by fixed-bed column adsorption experiments. Adsorbent synthesized at 700°C was found to have the highest surface area and surface basicity along with maximum CO2 adsorption capacity among the synthesized adsorbents. Breakthrough time and CO2 equilibrium adsorption capacity were investigated from the breakthrough curves and were found to decrease with increase in adsorption temperature. Adsorption process for carbon adsorbent-CO2 system was found to be reversible with stable adsorption capacity over four consecutive adsorption-desorption cycles. From three isotherm models used to analyze the equilibrium data, Temkin isotherm model presented a nearly perfect fit implying the heterogeneous adsorbent surface.

  18. Removal of Indigo Carmine Dye from Aqueous Solution Using Magnesium Hydroxide as an Adsorbent

    OpenAIRE

    Thimmasandra Narayan Ramesh; Vani Pavagada Sreenivasa

    2015-01-01

    Magnesium hydroxide is used as an adsorbent for the removal of indigo carmine dye from aqueous solution. We have investigated the effectiveness of removal of indigo carmine dye from aqueous solutions at pH 6-7 and 12-13 using magnesium hydroxide thereby varying the dose of the adsorbent, concentration of the dye, duration, and temperature. Structural transformations of adsorbent during the adsorption process at different pH values are monitored using powder X-ray diffraction and infrared spec...

  19. Cu Secondary Adsorption by Some Variable Charge Soils After Adsorbing SO42—

    Institute of Scientific and Technical Information of China (English)

    DONGYUAN-YAN; WANGSHU-YU

    1993-01-01

    Cu secondary adsorption by three variable charge soils collected from hubei Province and Hunan Province was investigated.The amount of Cu secondary adsorption increased with that of SO42- elementary adsorption and conformed with the Langmuir,freundlich and Temkin isotherms.Desorption of secondary-adsorbed Cu indicated that the hysteresis ratio decreased as Cu secondary adsorption increased,which meant that secondry-adsorbed Cu existed not only in the exchangeable form but also in the bridge form and specifically adsorbed form.The amount of Cu secondary adsorption increased with the temperature.

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

    Science.gov (United States)

    Tsitovich, A. P.

    2013-03-01

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

  1. Preparation and Characterization of a Novel Spherical Cellulose Adsorbent for Reduction Adsorption of Trichloroacetic Acid

    Institute of Scientific and Technical Information of China (English)

    LIN Chun-Xiang; TIAN Chen; LIU Yi-Fan; CHENG Yang-Jian; LIN Zhang; LIU Ming-Hua

    2014-01-01

    A novel spherical cellulose adsorbent has been prepared by homogeneous graft polymerization of N,N'-methylenebisacrylamide (MBA) onto cellulose in an ionic liquid,1-N-butyl-3-methylimidazolium chloride (BMIMC1),which was then partially amine methylated through Marmich reaction to get bifunctionalized materials containing both amide and sulphinate moities.Factors affecting the attachment of functional groups were investigated.The adsorbent was characterized by Elemental Analysis (EA),Fourier Transform Infrared Spectroscopy (FTIR) and Scanning Electron Microscope (SEM).Cellulose adsorbent was then tested for its potential applications in the reduction adsorption of trichloroacetic acid (TCAA) from aqueous solutions.

  2. Synthesis of highly effective adsorbents from natural raw materials (zeolites)

    International Nuclear Information System (INIS)

    Natural raw materials bentonite, silica tuff and diatomaceous earth from Macedonia were used in synthesis of zeolites type A, ZSM-5 and multilayer silicate magadiite-adsorbents. The bentonite was subject to pretreatment with acids (HCl and H2SO4 - 5, 10, 15 and W%) or NaOH, and used in synthesis of zeolite type A having molar ratio of: 2Na2O : Al2O3 : 2SiO2 : 100H2O. Silicate tuff was applied (without any pretreatment, in a two stage reaction) in a high temperature synthesis, using butylamine as an organic 'template' component in order to get high silica zeolite type ZSM-5 having molar ratio of: 59.37SiO2 : Al2O3 : 3.84Na2O : 1.90R2O : 2025.10H2O. Multilayer silicate magadiite MS-H was synthesized from natural raw material diatomaceous earth. The product with a molar ratio of: 8SiO2 : Na2O : 75H2O showed the best characteristics. The proposed method of alkaline pretreatment is a new one and it is acceptable from the economy point of view due to low energy consumption. The conclusion shows that the final result of the synthesis was not perfect, i.e. it has 70% of zeolite ZSM-5 and the rest were some amorphous phases. This product is suitable for industrial application in catalytic processes due to the fact that commercial catalyst contain typically 20 to 50% of zeolite type ZSM-5. On the other hand, the magadiite being multilayer silicate with no aluminium inside, is well suited as a carrier due to its ability of intercalation. The experimental results indicate that natural raw materials from Macedonia could be used for synthesis of synthetical silicates with high qualities and acceptable overall costs, specially when alkaline pretreatment is used. 14 refs., 4 tabs., 11 figs

  3. Dissolution improvement of nebivolol hydrochloride using solid dispersion adsorbate technique

    Directory of Open Access Journals (Sweden)

    Harsh Shah

    2015-01-01

    Full Text Available Nebivolol hydrochloride is unique antihypertensive drug, which gets completely absorbed upon oral administration, with t max 1.5-4 h. The poor aqueous solubility leads to slow rate of absorption. An attempt has been made to enhance dissolution of nebivolol (NB using solid dispersion (SD and SD adsorbate (SDA techniques. Various hydrophilic excipients such as polyethylene glycol 6000 (PEG, gelucire 50/13 (GL, and neusilin US2 (NUS at different ratios were used. The prepared SDA of NB was characterized for % drug yield and other physical characteristics and in vitro drug dissolution studies in 0.1N HCl (pH 1.2. The formulation optimized on the basis of in vitro drug dissolution and % drug content was also characterized by the Fourier transform infrared (FTIR spectroscopy; differential scanning calorimetry (DSC, X-ray powder diffractometry analysis (XRD. The FTIR study indicated no interaction between the drug and polymer. DSC thermograms showed the significant change in melting peak of the NB when prepared as SDA suggesting the change in crystallinity of NB. The data from the XRD showed that the drug was still detectable in its solid state in the SDA of PEG and disappeared in case of higher ratio of GL. An increased dissolution rate of NB at pH 1.2 was observed when the drug was dispersed in these carriers in the form of physical mixtures (PMs, SDs by solvent evaporation methods (SMs, SDs by fusion method and SDAs by fusion method. NB released faster from the SDAs than from the pure crystalline drug, the PMs, the SMs, or the SDs. Thus, this study was proved as a promising approach for the improvement of dissolution rate and solubility of NB.

  4. Single walled carbon nanotubes functionally adsorbed to biopolymers for use as chemical sensors

    Science.gov (United States)

    Johnson, Jr., Alan T.; Gelperin, Alan; Staii, Cristian

    2011-07-12

    Chemical field effect sensors comprising nanotube field effect devices having biopolymers such as single stranded DNA functionally adsorbed to the nanotubes are provided. Also included are arrays comprising the sensors and methods of using the devices to detect volatile compounds.

  5. Recovery of Th(IV) from aqueous solution by reassembled collagen-tannin fiber adsorbent

    International Nuclear Information System (INIS)

    A novel adsorbent, collagen immobilized tannin adsorbent (CITA), was prepared and its adsorption behaviors to Th(IV) were investigated. CITA was n fibrous state due to the reassembly of collagen molecules by the inducement of tannin. This adsorbent loaded a greater amount of tannin and exhibited higher adsorption capacity to Th(IV) than the tannin immobilized adsorbent prepared from collagen fiber. The adsorption of CITA to Th(IV) is mainly attributed to surface complexation, which is a pH- rather than an ionic strength-dependent process. The adsorption kinetics and isotherms were described by pseudo-second-order rate model and Freundlich equation, respectively. Column adsorption studies indicated that CITA is available for effectively recovering Th(IV) from aqueous solution. (author)

  6. A Cascaded Discharge Plasma-Adsorbent Technique for Engine Exhaust Treatment

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    A cascaded system of electrical discharges (non-thermal plasma) and adsorptionprocess was investigated for the removal of oxides of Nitrogen (NOx) and total hydrocarbons(THC) from an actual diesel engine exhaust. The non-thermal plasma and adsorption processeswere separately studied first and then the cascaded process was studied. In this study, differenttypes of adsorbents were used. The NOx removal efficiency was higher with plasma-associatedadsorption (cascaded) process compared to the individual processes and the removal efficiencywas found almost invariant in time. When associated by plasma, among the adsorbents studied,activated charcoal and MS-13X were more effective for NOx and THC removal respectively. Theexperiments were conducted at no load and at 50 % load conditions. The plasma reactor was keptat room temperature throughout the experiment, while the temperature of the adsorbent reactorwas varied. A relative comparison of adsorbents was discussed at the end.

  7. Synthesis and uranium adsorption performance of a novel modified lignin-based adsorbent

    International Nuclear Information System (INIS)

    The modified lignin-based adsorbent containing the strong-base and weak-base group, was prepared by two-step chemical modification of acid-precipitation lignin, which is low-cost, and abundant renewable natural polymers: (1) introduced weak-base group by mannich reaction; (2)introduced strong-base group by O-alkylatio reaction.The adsorbent was characterized by Fourier Transform Infrared Spectroscopy (FT-IR) and Elementary Analysis(EA), which demonstrated amino group was successfully introduced into the lignin. In order to assess the possibility of adsorption effect, the adsorption experiments of uranium on lignin-based adsorbent, were carried out in the static mode at room temperature. The removal rate of uranium of the wastewatere could reach 93%, under such conditions as pH value 2, uranium concentration 6 mg/L, and adsorbent dosage 10 g/L, etc. (authors)

  8. Synthesis and uranium adsorption performance of a novel modified lignin-based adsorbent

    International Nuclear Information System (INIS)

    The modified lignin-based adsorbent containing the strong-base and weak-base group, was prepared by two-step chemical modification of acid-precipitation lignin, which is a low-cost and abundant renewable natural polymer: 1) weak-base group introduced by Mannich reaction; 2) strong-base group introduced by O-alkylation reaction. The adsorbent was characterized by Fourier transform infrared spectroscopy (FT-IR) and elementary analysis (EA), which demonstrated amino group was successfully introduced into the lignin. In order to assess the adsorption effect, the uranium adsorption experiments of lignin-based adsorbent were carried out in the static mode at room temperature. The removal rate of uranium from the wastewater could reach 93% under such conditions as pH value 2, uranium concentration 6 mg/L, adsorbent dosage 10 g/L etc. (authors)

  9. Growth of Aligned Multiwall Carbon Nanotubes and the Effect of Adsorbates on the Field Emission Properties

    Science.gov (United States)

    Milne, W. I.; Teo, K. B. K.; Lansley, S. B.; Chhowalla, M.; Amaratunga, G. A. J.; Semet, V.; Binh, Vu Thien; Pirio, G.; Legagneux, P.

    2003-10-01

    In attempt to decipher the field emission characteristics of multiwall carbon nanotubes (MWCNTs), we have developed a fabrication method based on plasma enhanced chemical vapour deposition (PECVD) to provide utmost control of the nanotube structure such as their alignment, individual position, diameter, length and morphology. We investigated the field emission properties of these nanotubes to elucidate the effect of adsorbates on the nanotubes. Our results show that although the adsorbates cause an apparent lowering of the required turn on voltage/field of the nanotubes, the adsorbates undesirably cause a saturation of the current, large temporal fluctuations in the current, and also a deviation of the emission characteristics from Fowler-Nordheim like emission. The adsorbates are easily removed by extracting an emission current of 1 uA per nanotube or using a high applied electric field (˜25V/um).

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

    Science.gov (United States)

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

    2012-05-30

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

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

    Directory of Open Access Journals (Sweden)

    Kiyoshi Kawamura

    2009-02-01

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

  12. AMMONIA AND COD REMOVAL FROM SYNTHETIC LEACHATE USING RICE HUSK COMPOSITE ADSORBENT

    Directory of Open Access Journals (Sweden)

    Azhar Abdul Halim

    2011-06-01

    Full Text Available Ammonia and chemical oxygen demand (COD were the most two problematic parameters in the landfill leachate. In this study, a new composite adsorbent derived from rice husk ash waste is evaluated with respect to its ability to remove these contaminants from synthetic leachate. Results indicate that the new composite adsorbent is able to adsorb both ammonia and COD. It has a higher adsorption capacity for ammonia (Q = 2.2578 mg/g and an almost equal adsorption capacity for COD (Q = 2.8893 when compared with commercially activated carbon. The adsorption kinetics of this new product for ammonia and COD were primarily represented by the pseudo second-order mechanism. The overall adsorption rate of the ammonia and COD adsorption processes appears to be determined by chemisorption process. The regenerated composite adsorbent indicated higher adsorption capacities of ammonia and COD, i.e. 12.9366 mg/g and 3.1162 mg/g, respectively.

  13. Adsorption and Desorption of Carbon Dioxide and Water Mixtures on Synthetic Hydrophobic Carbonaceous Adsorbents

    Science.gov (United States)

    Finn, John E.; Harper, Lynn D. (Technical Monitor)

    1994-01-01

    Several synthetic carbonaceous adsorbents produced through pyrolysis of polymeric materials are available commercially. Some appear to have advantages over activated carbon for certain adsorption applications. In particular, they can have tailored hydrophobicities that are significantly greater than that of activated carbon, while moderately high surfaces areas are retained. These sorbents are being investigated for possible use in removing trace contaminants and excess carbon dioxide from air in closed habitats, plant growth chambers, and other applications involving purification of humid gas streams. We have analyzed the characteristics of a few of these adsorbents through adsorption and desorption experiments and standard characterization techniques. This paper presents pure and multicomponent adsorption data collected for carbon dioxide and water on two synthetic carbonaceous adsorbents having different hydrophobicities and capillary condensation characteristics. The observations are interpreted through consideration of the pore structure and surface chemistry of the solids and interactions between adsorbed carbon dioxide, water, and the solvent gas.

  14. ADSORPTION OF PHENOLIC COMPOUNDS ONTO THE SPHERICAL MACROPOROUS ADSORBENT BASED ON UREA—FORMALDEHYDE CONDENSED POLYMER

    Institute of Scientific and Technical Information of China (English)

    XuMingcheng; XUMancai; 等

    2000-01-01

    Adsorption of phenol,catechol and resorcinol,which vary in their ability to interact with the adsorbent through hydrogen bond,were used to investigate the adsorption mechanistic interaction.The adsorption enthalpies of the above mentioned compound onto the adsorbent were calculated and thermodynamic analysis was carried out.The results showed the adsorbent with the lowest adsorption enthalpies for the sorbate such as catechol with intermolecular hydrogen bond also display the lowest adsorption affinity.On the other hand,the more of the groups available for hydrogen bond interaction,the higher of the adsorption affinity.These observations support the contention that phenol adsorption is driven predominantly by specific interaction of the solute with active sites on the surface of the adsorbent.

  15. Inorganic ion exchangers and adsorbents for chemical processing in the nuclear fuel cycle

    International Nuclear Information System (INIS)

    The application of inorganic ion exchangers and adsorbents to both waste treatment and the recovery of fission products and actinides were of primary concern at this meeting. The meeting covered the two major fields of fundamental studies and industrial applications

  16. A novel aminated polymeric adsorbent for removing refractory dissolved organic matter from landfill leachate treatment plant

    Institute of Scientific and Technical Information of China (English)

    ZHANG Long; LI Aimin; WANG Jinnan; LU Yufei; ZHOU Youdong

    2009-01-01

    Refractory dissolved organic matter (DOM) from landfill leachate treatment plant was with high dissolved organic carbon (DOC) content.An aminated polymeric adsorbent NDA-8 with tertiary amino groups and sufficient mesopore was synthesized, which exhibited high adsorption capacity to the DOM (raw water after coagulation).Resin NDA-8 performed better in the uptake of the DOM than resin DAX-8 and A100.Electrostatic attraction was considered as the decisive interaction between the adsorbent and adsorbate.Special attention was paid to the correlation between porous structure and adsorption capacity.The mesopore of NDA-8 played a crucial role during uptake of the DOM.In general, resin in chloride form performed a higher removal rate of DOC.According to the column adsorption test, total adsorption capacity of NDA-8 was calculated to 52.28 mg DOC/mL wet resin.0.2 mol/L sodium hydroxide solution could regenerate the adsorbent efficiently.

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

    International Nuclear Information System (INIS)

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

  18. Removal and recycle of phosphate from treated water of sewage plants with zirconium ferrite adsorbent by high gradient magnetic separation

    Energy Technology Data Exchange (ETDEWEB)

    Ito, D; Nishimura, K; Miura, O [Graduate School of Science and Engineering, Tokyo Metropolitan University, Hachioji, Tokyo, 192-0397 (Japan)], E-mail: dai@eei.metro-u.ac.jp

    2009-03-01

    Zirconium ferrite particles are good adsorbent for phosphate ions. Magnetic separation characteristics for removal of phosphate from treated water of sewage plants with the adsorbent have been studied to prevent eutrophication of semi-enclosed bay, e.g. the bay of Tokyo. Based on the adsorption for the phosphate ions and ferromagnetic properties of the zirconium ferrite adsorbent, high gradient magnetic separation characteristics with using superconducting magnet was discussed. Very rapid magnetic filtration velocity, i.e. 1m/s, and regeneration properties of the adsorbent indicate that the zirconium ferrite is the excellent adsorbent for phosphorus removal and recycle from treated water of large scale sewage plants.

  19. Heterogeneous Reactions of Surface-Adsorbed Catechol: A Comparison of Tropospheric Aerosol Surrogates

    Science.gov (United States)

    Hinrichs, R. Z.; Woodill, L. A.

    2009-12-01

    Surface-adsorbed organics can alter the chemistry of tropospheric solid-air interfaces, such as aerosol and ground level surfaces, thereby impacting photochemical cycles and altering aerosol properties. The nature of the surface can also influence the chemistry of the surface-adsorbed organic. We employed diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS) to monitor the adsorption of gaseous catechol on several tropospheric aerosol surrogates and to investigate the subsequent reactivity of adsorbed-catechol with nitrogen dioxide and, in separate preliminary experiments, ozone. Graphite, kaolinite, and sodium halide (NaF, NaCl, NaBr) powders served as carbonaceous, mineral and sea salt aerosol surrogates, respectively. Broad OH stretching bands for adsorbed catechol shifted to lower wavenumber with peak frequencies following the trend NaBr > NaCl > NaF ≈ kaolinite, consistent with the increasing basicity of the halide anions and basic Brønsted sites on kaolinite. The dark heterogeneous reaction of NO2 with NaCl-adsorbed catechol at relative humidity (RH) 4-nitrocatechol and oxidation forming 1,2-benzoquinone and the ring cleavage product muconic acid, with product yields of 88%, 8%, and 4%, respectively. 4-Nitrocatechol was the dominant product for catechol adsorbed on NaF and kaolinite, while NaBr-adsorbed catechol produced less 4-nitrocatechol and more 1,2-benzoquinone and muconic acid. For all three sodium halides, the reactions of NO2 with adsorbed catechol were orders of magnitude faster than between NO2 and each NaX substrate. 4-Nitrocatechol rates and product yields were consistent with the relative ability of each substrate to enhance the deprotonated nature of adsorbed-catechol. Increasing the relative humidity caused the rate of each product channel to decrease and also altered the product branching ratios. Most notably, 1,2-benzoquinone formation decreased significantly even at 13% RH. The dramatic reactivity of surface-adsorbed

  20. PURIFICATION OF GINKGO LEAVES EXTRACT WITH MACROPOROUS ADSORBENT BASED ON UREA—FORMALDEHYDE CONDENSED POLYMERS

    Institute of Scientific and Technical Information of China (English)

    XUMingcheng; XUMancai; 等

    2000-01-01

    The relationship between the adsorption properties for the active components of ginkgo leaves and the structure of the adsorbents based on urea-formaldehyde condensed polymers was investigated.The results revealed that these adsorbents showed very high adsorpton selectivity for both flavonol glycosides and terpene lactones contained in ginkgo leaves.Thus,an adsorption separation procedure for purification of ginkgo leaves extracts was developed.

  1. Preparation and Adsorption Properties of PAM Based Adsorbents for Plasma Lipoproteins

    Institute of Scientific and Technical Information of China (English)

    Hai Tao LI; Zhi YUAN; Xin Fu CHEN; Bin LIU; Bin SHEN; Bing Lin HE

    2004-01-01

    Crosslinked macroporous polyacrylamide(PAM)was prepared with inverse phase suspension polymerization technique.After treatment with hydrazine,the polymer was functionalized with chloroacetic acid,trifluoroacetic acid diethylenetriaminepentaacetic acid (DEPAA), and maleic acid, respectively,and PAM based adsorbents bearing carboxyl functional groups for low density lipoprotein(LDL)apheresis use were obtained.The blood compatibility and the adsorption properties for plasma lipoproteins of PAM based adsorbents were investigated.

  2. Uses of -Fe2O3 and fly ash as solid adsorbents

    Indian Academy of Sciences (India)

    J Shakhapure; H Vijayanand; S Basavaraja; V Hiremath; A Venkataraman

    2005-12-01

    Solid adsorbents have shown great promise for control of particulate and non-particulate matter and as gas sensing devices in recent times. In the present study, adsorption of environmental toxic pollutant such as lead ions on solid adsorbents viz. -Fe2O3 and fly ash, are reported. Considerable adsorption was observed on fly ash when compared to -Fe2O3 surface. These studies are characterized by employing solid state and solution studies.

  3. Application of chemically modified beach sand as low cost efficient adsorbent for dye removal

    OpenAIRE

    Reza Ansari; Ali Mohammad-khah; Mansoureh Nazmi

    2013-01-01

    In the current work, beach sand (BS) and beach sand coated with polyaniline (BS/Pani) were used as an efficient green adsorbent for dye removal from aqueous solutions. Methylene blue (MB) was chosen as a test probe for the evaluation of the selected adsorbents for dye removal efficiency. The adsorption experiments were carried out in batch system and the effect of some important empirical parameters affecting adsorption processes were then investigated. The experimental data were also analyze...

  4. Narrow-pore zeolites and zeolite-like adsorbents for CO2 separation

    OpenAIRE

    Cheung, Ocean

    2014-01-01

    A range of porous solid adsorbents were synthesised and their ability to separate and capture carbon dioxide (CO2) from gas mixtures was examined. CO2 separation from flue gas – a type of exhaust gas from fossil fuel combustion that consists of CO2 mixed with mainly nitrogen and biogas (consists of CO2 mixed with mainly methane) were explicitly considered. The selected adsorbents were chosen partly due to their narrow pore sizes. Narrow pores can differentiate gas molecules of different sizes...

  5. Adsorption Kinetics for the Removal of Hazardous Dye Congo Red by Biowaste Materials as Adsorbents

    OpenAIRE

    Sumanjit Kaur; Seema Rani; Rakesh Kumar Mahajan

    2013-01-01

    The present work aims to investigate the removal of dye congo red from aqueous solutions by two low-cost biowaste adsorbents such as ground nut shells charcoal (GNC) and eichhornia charcoal (EC) under various experimental conditions. The effect of contact time, ionic strength, temperature, pH, dye concentration, and adsorbent dose on the removal of dye was studied. The kinetic experimental data were fitted to pseudo-first order, pseudo-second order, intraparticle diffusion, Elovich model, and...

  6. VALORIZATION AND BIODECOLORIZATION OF DYE ADSORBED ON LIGNOCELLULOSICS USING WHITE ROT FUNGI

    OpenAIRE

    Nesrin Ozmen,; Ozfer Yesilada

    2012-01-01

    Biosorption of dyes by lignocelluloses may be an effective method for removing dyes from textile effluents. However, the resulting dye-adsorbed lignocellulosic materials may constitute another pollution problem. An integrated method can solve this problem. Here, various lignocelluloses were tested for their Astrazon Black and Astrazon Blue dyes removal activities. The dye adsorbed after 30 min contact time was 90% (45 mg/L), 70% (35 mg/L), and 98% (49 mg/L) for wheat bran, pine cone, and cott...

  7. A novel approach for arsenic adsorbents regeneration using MgO

    OpenAIRE

    Tresintsi, Sofia; Simeonidis, Konstantinos; Katsikini, Maria; Paloura, Eleni; Bantsis, Georgios; Mitrakas, Manassis

    2014-01-01

    An integrated procedure for the regeneration of iron oxy-hydroxide arsenic adsorbents by granulated MgO is proposed in this study. A continuous recirculation configuration, with a NaOH solution flowing sequentially through the saturated adsorbent (leaching step) and the MgO (adsorption step) column beds, was optimized by utilizing the high arsenic adsorption efficiency of MgO at strong alkaline environments. Experimental results indicated that the total amount of leached arsenic was captured ...

  8. Auger electron spectroscopy as a tool for measuring intramolecular charges of adsorbed molecules

    Science.gov (United States)

    Magkoev, T. T.

    1993-10-01

    A way for the determination of the values of intramolecular charges of adsorbed molecules of some binary dielectrics, based on Auger electron spectroscopy (AES), is proposed. These values can be obtained from the coverage dependences of the ratios of intensities of anion KL 23L 23 and KL 1L 1 Auger transitions, which are sensitive to the amount of charge at the 2p-orbitals. As an example, MgO adsorbed on Mo(110) is presented.

  9. Quantification of adsorbed human serum albumin : a comparison between radioimmunoassay and simple null ellipsometry

    OpenAIRE

    Benesch, Johan; Askendal, A.; Tengvall, P.

    2000-01-01

    Radioimmunoassay (RIA) and null ellipsometry are two common methods to quantify adsorbed proteins. However, the accuracy of null ellipsometry with a constant protein refractive index (n 1.465, k 0) at l 632.8 nm has this far not been explored. The present study compared the methods, and the degree of agreement between the simplified single wavelength null ellipsometry and RIA to quantify adsorbed proteins was explored on different surfaces. The quantification methods agreed well w...

  10. Mitigation of chromatography adsorbent lot performance variability through control of buffer solution design space.

    Science.gov (United States)

    Aono, Hiromasa; Iliescu, Ionela; Cecchini, Doug; Wood, Susanne; McCue, Justin T

    2013-11-29

    The separation of undesired product-related impurities often poses a challenge in the purification of protein therapeutic species. Product-related impurity species, which may consist of undesirable isoforms, aggregated, or misfolded variants of the desired monomeric form of the product, can be challenging to remove using preparatory scale chromatographic techniques. When using anion exchange chromatography to remove undesirable product-related impurities, the separation can be highly sensitive to relatively small changes in the chromatography operating conditions, including changes to buffer solution pH, buffer solution conductivity protein loading, and operating temperature. When performing difficult separations, slight changes to the chemical and physical properties of the anion exchange adsorbent lot may also impact the separation profile. Such lot-to-lot variability may not be readily measurable by the adsorbent manufacturer, since variability can be highly dependent on a specific protein separation. Consequently, manufacturers of chromatographic adsorbents may not be able to control adsorbent lot to lot variability tightly enough to prevent differences from occurring when performing difficult product-related separations at the preparatory scale. In such cases, it is desirable to design a chromatography step with a control strategy which accounts for adsorbent lot to lot variability in the separation performance. In order to avoid the undesired changes to process consistency and product quality, a proper adjustment of the column operating conditions can be implemented, based on the performance of each adsorbent lot or lot mixture. In this work, we describe how the adjustment of the column buffer solution composition can be used as a design space based-control strategy used to ensure consistent process performance and product quality are achieved for an anion exchange chromatography step susceptible to adsorbent lot to lot performance variability. In addition, a

  11. The Effect of Melatonin Adsorbed to Polyethylene Glycol Microspheres on the Survival of MCF-7 Cells.

    Science.gov (United States)

    França, Eduardo Luzía; Honorio-França, Adenilda Cristina; Fernandes, Rubian Trindade da Silva; Marins, Camila Moreira Ferreira; Pereira, Claudia Cristina de Souza; Varotti, Fernando de Pilla

    2016-01-01

    Although melatonin exhibits oncostatic properties such as antiproliferative effects, the oral bioavailability of this hormone is less than 20%. Modified drug release systems have been used to improve the pharmacological efficiency of drugs. These systems can change the pharmacokinetics and biodistribution of the associated drugs. Thus, this study investigated the effect of melatonin adsorbed to polyethylene glycol (PEG) microspheres on MCF-7 human breast cancer cells. The MCF-7 cells were obtained from the American Type Culture Collection. MCF-7 cells were preincubated for 24 h with or without melatonin (100 ng/ml), PEG microspheres or melatonin adsorbed to PEG microspheres (100 ng/ml). Viability, intracellular calcium release and apoptosis in MCF-7 cells were determined by flow cytometry. MCF-7 cells incubated with melatonin adsorbed to PEG microspheres showed a lower viability rate (40.0 ± 8.3 with melatonin adsorbed to PEG microspheres compared to 54.1 ± 7.3 with melatonin; 81.8 ± 12.5 with PEG microsphere and 92.7 ± 4.1 with medium), increased spontaneous intracellular Ca2+ release (27.0 ± 8.6 with melatonin adsorbed to PEG microspheres compared to 21.5 ± 13.4 with melatonin; 10.1 ± 5.4 with PEG microsphere and 9.1 ± 5.6 with medium) and increased apoptosis index (51.2 ± 2.7 with melatonin adsorbed to PEG microspheres compared to 36.0 ± 2.1 with melatonin; 4.9 ± 0.5 with PEG microsphere and 3.1 ± 0.6 with medium). The results indicate that melatonin adsorbed to PEG microspheres exerts antitumor effects on human MCF-7 breast cancer cells. However, clinical tests must be performed to confirm the use of melatonin adsorbed to PEG microspheres as an alternative therapy against cancer. PMID:26445481

  12. Separation and Purification of Thrombin-like Enzymes by Affinity Adsorbents

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    An affinity adsorbent, benzamidineSepharose 4B, was used to separate and purify thrombinlike enzymes. The paminobenzamidine as a specific ligand was coupled to the matrix-Sepharose 4B. The recombinant thrombinlike enzyme-defibrase was used as a model in order to evaluate the efficiency of this biospecific affinity adsorbent. The homogeneity of the enzyme preparation was comfirmed as one band on sodium dodecyl sulfatepolyacrylamide gel electrophoresis.

  13. Imaging the potential distribution of charged adsorbates on graphene by low-energy electron holography

    CERN Document Server

    Latychevskaia, Tatiana; Escher, Conrad; Fink, Hans-Werner

    2016-01-01

    While imaging individual atoms can routinely be achieved in high resolution transmission electron microscopy, visualizing the potential distribution of individually charged adsorbates leading to a phase shift of the probing electron wave is still a challenging task. Since low-energy electrons are sensitive to localized potential gradients, we employed this tool in the 30 eV kinetic energy range to visualize the potential distribution of localized charged adsorbates present on free-standing graphene.

  14. Development of nitrogen enriched nanostructured carbon adsorbents for CO2 capture.

    Science.gov (United States)

    Goel, Chitrakshi; Bhunia, Haripada; Bajpai, Pramod K

    2015-10-01

    Nanostructured carbon adsorbents containing high nitrogen content were developed by templating melamine-formaldehyde resin in the pores of mesoporous silica by nanocasting technique. A series of adsorbents were prepared by altering the carbonization temperature from 400 to 700 °C and characterized in terms of their textural and morphological properties. CO2 adsorption performance was investigated at various temperatures from 30 to 100 °C by using a thermogravimetric analyzer under varying CO2 concentrations. Multiple adsorption-desorption experiments were also carried out to investigate the adsorbent regenerability. X-ray diffraction (XRD) and transmission electron microscopy (TEM) confirmed the development of nanostructured materials. Fourier transform infrared spectroscopy (FTIR) and elemental analysis indicated the development of carbon adsorbents having high nitrogen content. The surface area and pore volume of the adsorbent carbonized at 700 °C were found to be 266 m(2) g(-1) and 0.25 cm(3) g(-1) respectively. CO2 uptake profile for the developed adsorbents showed that the maximum CO2 adsorption occurred within ca. 100 s. CO2 uptake of 0.792 mmol g(-1) at 30 °C was exhibited by carbon obtained at 700 °C with complete regenerability in three adsorption-desorption cycles. Furthermore, kinetics of CO2 adsorption on the developed adsorbents was studied by fitting the experimental data of CO2 uptake to three kinetic models with best fit being obtained by fractional order kinetic model with error% within range of 5%. Adsorbent surface was found to be energetically heterogeneous as suggested by Temkin isotherm model. Also the isosteric heat of adsorption for CO2 was observed to increase from ca. 30-44 kJ mol(-1) with increase in surface coverage.

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

    International Nuclear Information System (INIS)

    Metal adsorbent containing hydroxamic acid groups was successfully synthesized by radiation-induced graft copolymerization of methyl acrylate (MA) onto cassava starch. The optimum conditions for grafting were studied in terms of % degree of grafting (Dg). Conversion of the ester groups present in poly(methyl acrylate)-grafted-cassava starch copolymer into hydroxamic acid was carried out by treatment with hydroxylamine (HA) in the presence of alkaline solution. The maximum percentage conversion of the ester groups of the grafted copolymer, %Dg = 191 (7.63 mmol/g of MA), into the hydroxamic groups was 70% (5.35 mmol/g of MA) at the optimum conditions: in a mixture solution of 20% HA (w/v) and methanol solution (methanol:H2O = 5:1) 300 mL, pH 13, reaction time 2 h, and 20 g of grafted copolymer. The adsorbent was characterized by FTIR, TGA, and DSC. The presence of electron donating groups in adsorbent containing hydroxamic acid groups gives the ability to form polycomplexes with metal ions. The ability of the adsorbent to adsorb various metals was investigated in order to evaluate the possibility of its use in metal adsorption. The adsorbent exhibited a remarkable % adsorption for Cd2+, Al3+, UO22+, V5+ and Pb2+ at pH 3, 4, 5, 4, and 3, respectively. The adsorbent of 191%Dg had total adsorption capacities of 2.6, 1.46, 1.36, 1.15, and 1.6 mmol/g adsorbent for Cd2+, Al3+, UO22+, V5+ and Pb2+, respectively, in the batch mode adsorption. (author)

  16. Experimental study and modelling of competitive adsorption equilibria of aromatics in liquid phase on X and Y faujasites; Etude experimentale et modelisation des equilibres d'adsorption competitive d'aromatiques en phase liquide sur des faujasites X et Y

    Energy Technology Data Exchange (ETDEWEB)

    Tournier, H.

    2000-10-13

    The separation of p-xylene from C{sub 8} aromatics is performed industrially by selective adsorption on zeolitic molecular sieves. The aim of this work is to study and model adsorption equilibria of C{sub 8} and C{sub 10} aromatics on X and Y zeolites. The experimental data are obtained by an entirely automated equipment allowing to work in a large range of temperature (50 deg. C - 250 deg. C). With this equipment, we can follow the evolution of the composition of the liquid phase and determine the composition of the adsorbed phase at equilibrium by a mass balance calculation and with an inert component. Two analytical techniques are used to determine the composition of the liquid phase: (1) a classical method using a gas chromatograph (GC) allowed to measure selectivities in the concentration range (3%-97%) in a component; (2) an original method based on the use and on the measure of {sup 13}C labelled xylenes was developed to investigate the ranges of strongly contrasting concentrations [0-3%] and [97%-100%] in a component, which are representative of high purity domains. Lastly, three thermodynamic models are used to describe the adsorption equilibria: the Langmuir-Freundlich model, the quasi-chemical model and the statistical model. The last model is the more interesting, because it is based on physical considerations. A new statistical model has been developed with taking into account some observations coming from adsorption phenomenon in zeolites. (author)

  17. Geometric and electronic structures of potassium-adsorbed rubrene complexes

    Science.gov (United States)

    Li, Tsung-Lung; Lu, Wen-Cai

    2015-06-01

    The geometric and electronic structures of potassium-adsorbed rubrene complexes are studied in this article. It is found that the potassium-rubrene (K1RUB) complexes inherit the main symmetry characteristics from their pristine counterparts and are thus classified into D2- and C2h-like complexes according to the relative orientations of the four phenyl side groups. The geometric structures of K1RUB are governed by two general effects on the total energy: Deformation of the carbon frame of the pristine rubrene increases the total energy, while proximity of the potassium ion to the phenyl ligands decreases the energy. Under these general rules, the structures of D2- and C2h-like K1RUB, however, exhibit their respective peculiarities. These peculiarities can be illustrated by their energy profiles of equilibrium structures. For the potassium adsorption-sites, the D2-like complexes show minimum-energy basins, whereas the C2h-like ones have single-point minimum-energies. If the potassium atom ever has the energy to diffuse from the minimum-energy site, the potassium diffusion path on the D2-like complexes is most likely along the backbone in contrast to the C2h-like ones. Although the electronic structures of the minimum-energy structures of D2- and C2h-like K1RUB are very alike, decompositions of their total spectra reveal insights into the electronic structures. First, the spectral shapes are mainly determined by the facts that, in comparison with the backbone carbons, the phenyl carbons have more uniform chemical environments and far less contributions to the electronic structures around the valence-band edge. Second, the electron dissociated from the potassium atom mainly remains on the backbone and has little effects on the electronic structures of the phenyl groups. Third, the two phenyls on the same side of the backbone as the potassium atom have more similar chemical environments than the other two on the opposite side, which leads to the largely enhanced

  18. Geometric and electronic structures of potassium-adsorbed rubrene complexes

    Energy Technology Data Exchange (ETDEWEB)

    Li, Tsung-Lung, E-mail: quantum@mail.ncyu.edu.tw [Department of Electrophysics, National Chia-Yi University, Chiayi 60004, Taiwan (China); Lu, Wen-Cai, E-mail: wencailu@jlu.edu.cn [Laboratory of Fiber Materials and Modern Textile and Growing Base for State Key Laboratory, College of Physics, Qingdao University, Qingdao, Shandong 266071 (China); State Key Laboratory of Theoretical and Computational Chemistry, Institute of Theoretical Chemistry, Jilin University, Changchun, Jilin 130021 (China)

    2015-06-28

    The geometric and electronic structures of potassium-adsorbed rubrene complexes are studied in this article. It is found that the potassium-rubrene (K{sub 1}RUB) complexes inherit the main symmetry characteristics from their pristine counterparts and are thus classified into D{sub 2}- and C{sub 2h}-like complexes according to the relative orientations of the four phenyl side groups. The geometric structures of K{sub 1}RUB are governed by two general effects on the total energy: Deformation of the carbon frame of the pristine rubrene increases the total energy, while proximity of the potassium ion to the phenyl ligands decreases the energy. Under these general rules, the structures of D{sub 2}- and C{sub 2h}-like K{sub 1}RUB, however, exhibit their respective peculiarities. These peculiarities can be illustrated by their energy profiles of equilibrium structures. For the potassium adsorption-sites, the D{sub 2}-like complexes show minimum-energy basins, whereas the C{sub 2h}-like ones have single-point minimum-energies. If the potassium atom ever has the energy to diffuse from the minimum-energy site, the potassium diffusion path on the D{sub 2}-like complexes is most likely along the backbone in contrast to the C{sub 2h}-like ones. Although the electronic structures of the minimum-energy structures of D{sub 2}- and C{sub 2h}-like K{sub 1}RUB are very alike, decompositions of their total spectra reveal insights into the electronic structures. First, the spectral shapes are mainly determined by the facts that, in comparison with the backbone carbons, the phenyl carbons have more uniform chemical environments and far less contributions to the electronic structures around the valence-band edge. Second, the electron dissociated from the potassium atom mainly remains on the backbone and has little effects on the electronic structures of the phenyl groups. Third, the two phenyls on the same side of the backbone as the potassium atom have more similar chemical environments

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

    International Nuclear Information System (INIS)

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

  20. 2-chlorophenol sorption from aqueous solution using granular activated carbon and polymeric adsorbents

    Science.gov (United States)

    Ghatbandhe, A. S.; Jahagirdar, H. G.; Yenkie, M. K. N.; Deosarkar, S. D.

    2013-08-01

    Adsorption equilibrium and kinetics of 2-chlorophenol (2-CP) one of the chlorophenols (CPs) onto bituminous coal based Filtrasorb-400 grade granular activated carbon and three different types of polymeric adsorbents were studied in aqueous solution in a batch system. Langmuir isotherm models were applied to experimental equilibrium data of 2-CP adsorption. Equilibrium data fitted very well to the Langmuir equilibrium models of 2-CP. Adsorbent monolayer capacity Q Langmuir constant b and adsorption rate constants k a were evaluated. 2-CP adsorption using GAC is very rapid in the first hour of contact where 70-80% of the adsorbate is removed by GAC followed by a slow approach to equilibrium. Whereas in case of polymeric adsorbents 60-65% of the adsorbate is removed in the first 30 min which is then followed by a slow approach to equilibrium. The order of adsorption of 2-CP on different adsorbents used in the study is found to be in following order: F-400 > XAD-1180 > XAD-4 > XAD-7HP.

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

    Directory of Open Access Journals (Sweden)

    BUCIŞCANU Ingrid

    2016-05-01

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

  2. Preparations of PAN-based adsorbers for separation of cesium and cobalt from radioactive wastes

    Energy Technology Data Exchange (ETDEWEB)

    Nilchi, A. [Jaber Ibn Hayan Research Laboratories, Atomic Energy Organization of Iran, P.O. Box 11365/8486, Tehran (Iran, Islamic Republic of)]. E-mail: anilchi@aeoi.org.ir; Atashi, H. [Sistan and Baluchestan University, Zahedan (Iran, Islamic Republic of); Javid, A.H. [Azad University, Tehran (Iran, Islamic Republic of); Saberi, R. [Jaber Ibn Hayan Research Laboratories, Atomic Energy Organization of Iran, P.O. Box 11365/8486, Tehran (Iran, Islamic Republic of)

    2007-05-15

    Ion-exchange adsorbers are widely used for radioisotope separation, as well as for the removal of hazardous fission products from aqueous waste prior to discharge to the environment. Inorganic exchangers are of particular interest because of their resistance to radiolytic damage and selectivity for specific fission products. Composite inorganic-organic adsorbers represent a group of inorganic ion exchangers modified by using binding organic material, polyacrylonitrile, for preparation of larger size particles with higher granular strength. At the same time, kinetics of ion exchange and sorption capacity of such composite adsorbers are not influenced by the binding polymer. The contents of active component in composite adsorber were varied over a very broad range of 5-95% of the dry weight of the composite adsorber, and tested for separation and concentration of various stimulated wastes. Three different inorganic sorbents, granular hexacyanoferrate-based ion exchanger, were developed for the removal of Cs and Co ions from waste solutions containing different complexing agents as detergents. Radiation and thermal stability studies show that these adsorbents can be used for medium-active waste treatment.

  3. Low-cost magnetic adsorbent for As(III) removal from water: adsorption kinetics and isotherms.

    Science.gov (United States)

    Kango, Sarita; Kumar, Rajesh

    2016-01-01

    Magnetite nanoparticles as adsorbent for arsenic (As) were coated on sand particles. The coated sand was used for the removal of highly toxic element 'As(III)' from drinking water. Here, batch experiments were performed with the variation of solution pH, adsorbent dose, contact time and initial arsenic concentration. The adsorbent showed significant removal efficiency around 99.6 % for As(III). Analysis of adsorption kinetics revealed that the adsorbent follows pseudo-second-order kinetics model showing R (2) = 0.999, whereas for pseudo-first-order kinetics model, the value of R (2) was 0.978. In the case of adsorption equilibrium, the data is well fitted with Langmuir adsorption isotherm model (R (2) > 0.99), indicating monolayer adsorption of As(III) on the surface of adsorbent. The existence of commonly present ions in water influences the removal efficiency of As(III) minutely in the following order PO4 (3-) > HCO3 (-) > Cl(-) > SO4 (2-). The obtained adsorbent can be used to overcome the problem of water filtration in rural areas. Moreover, as the nano-magnetite is coated on the sand, it avoids the problem of extraction of nanoparticles from treated water and can easily be removed by a simple filtration process. PMID:26711813

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2007-06-18

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

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

    Science.gov (United States)

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

    2014-12-01

    Hydrophobic interaction has been considered to be responsible for adsorption of perfluorooctanesulfonate (PFOS) on the surface of hydrophobic adsorbents, but the long C-F chain in PFOS is not only hydrophobic but also oleophobic. In this study, for the first time we propose that air bubbles on the surface of hydrophobic carbonaceous adsorbents play an important role in the adsorption of PFOS. The level of adsorption of PFOS on carbon nanotubes (CNTs), graphite (GI), graphene (GE), and powdered activated carbon (PAC) decreases after vacuum degassing. Vacuum degassing time and pressure significantly affect the removal of PFOS by these adsorbents. After vacuum degassing at 0.01 atm for 36 h, the extent of removal of PFOS by the pristine CNTs and GI decreases 79% and 74%, respectively, indicating the main contribution of air bubbles to PFOS adsorption. When the degassed solution is recontacted with air during the adsorption process, the removal of PFOS recovers to the value obtained without vacuum degassing, further verifying the key role of air bubbles in PFOS adsorption. By theoretical calculation, the distribution of PFOS in air bubbles on the adsorbent surfaces is discussed, and a new schematic sorption model of PFOS on carbonaceous adsorbents in the presence of air bubbles is proposed. The accumulation of PFOS at the interface of air bubbles on the adsorbents is primarily responsible for its adsorption, providing a new mechanistic insight into the transport, fate, and removal of PFOS. PMID:25365738

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

    Science.gov (United States)

    Moritz, Michał; Geszke-Moritz, Małgorzata

    2014-08-01

    The removal of two selected environmental pollutants such as 2,4-dichlorophenoxyacetic acid (2,4-D) and Triclosan (TC) was examined by adsorption experiments on the modified SBA-15 and MCF mesoporous silicas. Mesoporous adsorbents were modified by a grafting process with (3-aminopropyl)triethoxysilane (APTES) and 1-[3-(trimethoxysilyl)propyl]urea (TMSPU). Mesoporous materials were synthesized and characterized by N2 adsorption-desorption experiment, transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FT-IR), elemental analysis and adsorption studies. The results show that both APTES-functionalized SBA-15 and MCF nanoporous carriers are potentially good adsorbents for the removal of 2,4-D in a wide range of concentrations from 0.1 to 4 mg/cm(3). Maximum adsorption capacity of as-modified adsorbents for 2,4-D estimated from the Langmuir model was ~280 mg/g. The ionic interaction between the adsorbent and 2,4-D seems to play a key role in the adsorption process of the pollutant on APTES-modified siliceous matrices. The efficiency of TC sorption onto all prepared mesoporous adsorbents was significantly lower as compared to the entrapment of 2,4-D. Experimental data were best fitted by the Langmuir isotherm model. The results of this study suggest that mesoporous silica-based materials are promising adsorbents for the removal of selected organic pollutants.

  7. Adsorbate modification of the structural, electronic, and magnetic properties of ferromagnetic fcc {110} surfaces

    Science.gov (United States)

    Gunn, D. S. D.; Jenkins, Stephen J.

    2011-03-01

    We identify trends in structural, electronic, and magnetic modifications that occur on ferromagnetic {110} surfaces upon varying either the substrate material or the adsorbate species. First, we have modeled the adsorption of several first-row p-block elements on the surface of fcc Co{110} at two coverages [0.5 and 1.0 monolayer (ML)]. All adsorbates were found to expand the distance between the first and second substrate layers and to contract the distance between the second and third layers. The energetic location of a characteristic trough in the density-of-d-states difference plot correlates with the direction of the adsorbate magnetic coupling to the surface, and a trend of antiferromagnetic to ferromagnetic coupling to the surface was observed across the elements from boron to fluorine. A high fluorine adatom coverage (1.0 ML) was found to enhance the surface spin magnetic moment by 11%. Second, we also calculate and contrast adsorption of 0.5 and 1.0 ML of carbon, nitrogen, and oxygen adatoms on fcc iron, cobalt, and nickel {110} surfaces and compare the structural, electronic, and magnetic properties of these systems. Carbon and nitrogen are found to couple antiferromagnetically, and oxygen ferromagnetically, to all surfaces. It was found that antiferromagnetically coupled adsorbates retained their largest spin moment values on iron, whereas ferromagnetically coupled adsorbates possessed their lowest moments on this surface. The strongly localized influence of these adsorbates is clearly illustrated in partial density-of-states plots for the surface atoms.

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

    International Nuclear Information System (INIS)

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

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

    International Nuclear Information System (INIS)

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

  10. Performance of Laterite Soil Grains as Adsorbent in the Removal of Chromium

    Directory of Open Access Journals (Sweden)

    Syama I J

    2015-04-01

    Full Text Available The present study aims to examine the efficiency of laterite grains (LG and acid activated laterite grains (AALG as an adsorbent for removal hexavalent chromium and ferric ion from synthetic wastewater, under laboratory conditions. Adsorption of hexavalent chromium and ferric ion from synthetic wastewater is examined by batch and column studies wherein it is found to be dependent on pH, Contact time, adsorbent dosage and initial adsorbate concentration. Percentage removal enhances with the increase in adsorbent dosage and with low pH, the optimal removal is achieved at pH=2. AALG is found to investigate possibility of improvement in removal efficiency of hexavalent chromium. The removal efficiency of AALG is found to be significantly higher than the efficiency obtained from LG, at pH=7. An adsorbent dosage 2g of LG is found to be optimum for removal of ferric ion with low initial concentration of 2.5 mg/L. The equilibrium adsorption data obtained from batch studies were fitted with Langmuir and freundlich isotherm for both hexavalent chromium and ferric ions. The percentage removal obtained from batch adsorption studies were found to be higher than that obtained by column studies for both the adsorbates.

  11. Low-cost magnetic adsorbent for As(III) removal from water: adsorption kinetics and isotherms.

    Science.gov (United States)

    Kango, Sarita; Kumar, Rajesh

    2016-01-01

    Magnetite nanoparticles as adsorbent for arsenic (As) were coated on sand particles. The coated sand was used for the removal of highly toxic element 'As(III)' from drinking water. Here, batch experiments were performed with the variation of solution pH, adsorbent dose, contact time and initial arsenic concentration. The adsorbent showed significant removal efficiency around 99.6 % for As(III). Analysis of adsorption kinetics revealed that the adsorbent follows pseudo-second-order kinetics model showing R (2) = 0.999, whereas for pseudo-first-order kinetics model, the value of R (2) was 0.978. In the case of adsorption equilibrium, the data is well fitted with Langmuir adsorption isotherm model (R (2) > 0.99), indicating monolayer adsorption of As(III) on the surface of adsorbent. The existence of commonly present ions in water influences the removal efficiency of As(III) minutely in the following order PO4 (3-) > HCO3 (-) > Cl(-) > SO4 (2-). The obtained adsorbent can be used to overcome the problem of water filtration in rural areas. Moreover, as the nano-magnetite is coated on the sand, it avoids the problem of extraction of nanoparticles from treated water and can easily be removed by a simple filtration process.

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

    Science.gov (United States)

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

    2015-09-01

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

  13. Preparation of metal adsorbent from poly(methyl acrylate)-grafted-cassava starch via gamma irradiation

    International Nuclear Information System (INIS)

    Metal adsorbent containing hydroxamic acid groups was successfully synthesized by radiation-induced graft copolymerization of methyl acrylate (MA) onto cassava starch. The optimum conditions for grafting were studied in terms of % degree of grafting (Dg). Conversion of the ester groups present in poly(methyl acrylate)-grafted-cassava starch copolymer into hydroxamic acid was carried out by treatment with hydroxylamine (HA) in the presence of alkaline solution. The maximum percentage conversion of the ester groups of the grafted copolymer, % Dg=191 (7.63 mmol/g of MA), into the hydroxamic groups was 70% (5.35 mmol/g of MA) at the optimum condition. The adsorbent of 191%Dg had total adsorption capacities of 2.6, 1.46, 1.36, 1.15 and 1.6 mmol/g-adsorbent for Cd2+, Al3+, UO22+, V5+ and Pb2+, respectively, in the batch mode adsorption. - Highlights: ► Adsorbent containing hydroxamic acid group was prepared by radiation-induced grafting. ► The adsorbent exhibited a remarkable % adsorption for Cd2+, Al3+, UO22+, V5+ and Pb2+. ► The selectivity of adsorbent towards metal ions used is in this order: Cd2+>Pb2+> Al3+> UO22+ > V5+.

  14. Adsorbent filled membranes for gas separation. Part 1. Improvement of the gas separation properties of polymeric membranes by incorporation of microporous adsorbents

    NARCIS (Netherlands)

    Duval, J.-M.; Folkers, B.; Mulder, M.H.V.; Desgrandchamps, G.; Smolders, C.A.

    1993-01-01

    The effect of the introduction of specific adsorbents on the gas separation properties of polymeric membranes has been studied. For this purpose both carbon molecular sieves and zeolites are considered. The results show that zeolites such as silicate-1, 13X and KY improve to a large extent the separ

  15. Adsorption capacities of activated carbons for geosmin and 2-methylisoborneol vary with activated carbon particle size: Effects of adsorbent and adsorbate characteristics.

    Science.gov (United States)

    Matsui, Yoshihiko; Nakao, Soichi; Sakamoto, Asuka; Taniguchi, Takuma; Pan, Long; Matsushita, Taku; Shirasaki, Nobutaka

    2015-11-15

    The adsorption capacities of nine activated carbons for geosmin and 2-methylisoborneol (MIB) were evaluated. For some carbons, adsorption capacity substantially increased when carbon particle diameter was decreased from a few tens of micrometers to a few micrometers, whereas for other carbons, the increase of adsorption capacity was small for MIB and moderate for geosmin. An increase of adsorption capacity was observed for other hydrophobic adsorbates besides geosmin and MIB, but not for hydrophilic adsorbates. The parameter values of a shell adsorption model describing the increase of adsorption capacity were negatively correlated with the oxygen content of the carbon among other characteristics. Low oxygen content indicated low hydrophilicity. The increase of adsorption capacity was related to the hydrophobic properties of both adsorbates and activated carbons. For adsorptive removal of hydrophobic micropollutants such as geosmin, it is therefore recommended that less-hydrophilic activated carbons, such as coconut-shell-based carbons, be microground to a particle diameter of a few micrometers to enhance their equilibrium adsorption capacity. In contrast, adsorption by hydrophilic carbons or adsorption of hydrophilic adsorbates occur in the inner pores, and therefore adsorption capacity is unchanged by particle size reduction. PMID:26302219

  16. Adsorption capacities of activated carbons for geosmin and 2-methylisoborneol vary with activated carbon particle size: Effects of adsorbent and adsorbate characteristics.

    Science.gov (United States)

    Matsui, Yoshihiko; Nakao, Soichi; Sakamoto, Asuka; Taniguchi, Takuma; Pan, Long; Matsushita, Taku; Shirasaki, Nobutaka

    2015-11-15

    The adsorption capacities of nine activated carbons for geosmin and 2-methylisoborneol (MIB) were evaluated. For some carbons, adsorption capacity substantially increased when carbon particle diameter was decreased from a few tens of micrometers to a few micrometers, whereas for other carbons, the increase of adsorption capacity was small for MIB and moderate for geosmin. An increase of adsorption capacity was observed for other hydrophobic adsorbates besides geosmin and MIB, but not for hydrophilic adsorbates. The parameter values of a shell adsorption model describing the increase of adsorption capacity were negatively correlated with the oxygen content of the carbon among other characteristics. Low oxygen content indicated low hydrophilicity. The increase of adsorption capacity was related to the hydrophobic properties of both adsorbates and activated carbons. For adsorptive removal of hydrophobic micropollutants such as geosmin, it is therefore recommended that less-hydrophilic activated carbons, such as coconut-shell-based carbons, be microground to a particle diameter of a few micrometers to enhance their equilibrium adsorption capacity. In contrast, adsorption by hydrophilic carbons or adsorption of hydrophilic adsorbates occur in the inner pores, and therefore adsorption capacity is unchanged by particle size reduction.

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

    International Nuclear Information System (INIS)

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

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

    Energy Technology Data Exchange (ETDEWEB)

    Visa, Maria, E-mail: maria.visa@unitbv.ro [Transilvania University of Brasov, Department Renewable Energy Systems and Recycling, Eroilor 29, 500036 Brasov (Romania)

    2012-12-15

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

  19. Comparison of Fixed and Fluidized Beds Adsorber with Economic, Engineering, and Environmental approach

    Directory of Open Access Journals (Sweden)

    SEDIGHEH ATRKAR-ROSHAN

    2015-10-01

    Full Text Available Release  Volatile  organic  compounds  (VOCs  as  environmental  and  occupational  pollutant  cause  macro perspective affect such as climate change, humans and economic consequences. Although fixed bed absorber is widely used as a controlling method because of its economically and availability, but these absorbers are facing some issue like high pressure drop, non-uniform distribution of fluid, channeling and blocking. Fixed and fluidized beds adsorbent was compared from three economic, environmental and engineering perspectives using Multi Criteria Decision Making analysis (MCDA technique. An annular fluidized bed adsorber was designed and charged with 50-100 µm (100-140 ASTM mesh activated carbon (AC particles. Effects of factors like flow rate, particle size, inlet concentration and adsorption capacity of VOCs was investigated under steady state. In the flow rate less than 0.25(Lit.min-1, inlet gas slowly passes through the void spaces of the bed’s particles. By increasing the inlet flow from 0.3(Lit/min-1, bubbles start to form in the bed and the bed pressure drop decrease. The pressure drop of 6 (g of AC in minimum fluidization velocity was 20(KN.m-2. However, the pressure drop of 10 and 20(g of AC were 150 and 420(KN.m-2 respectively. “maximin” technique used for comparison of two beds indicated that minimum score of pack bed absorber are 0.37 while the minimum score of fluidized bed adsorber are 0.5. It indicated when the adsorbent particles are smaller, fluidized bed adsorber are more suitable to use. In addition, using MCDA technique indicated that annular fluidized bed adsorber could considered as an alternative of fixed beds adsorber.

  20. Promotion of CO oxidation on PdO(101) by adsorbed H2O

    Science.gov (United States)

    Choi, Juhee; Pan, Li; Mehar, Vikram; Zhang, Feng; Asthagiri, Aravind; Weaver, Jason F.

    2016-08-01

    We investigated the influence of adsorbed H2O on the oxidation of CO on PdO(101) using temperature programmed reaction spectroscopy (TPRS), reflection absorption infrared spectroscopy (RAIRS) and density functional theory (DFT) calculations. We find that water inhibits CO adsorption on PdO(101) by site blocking, but also provides a more facile pathway for CO oxidation compared with the bare oxide surface. In the presence of adsorbed H2O, the oxidation of CO on PdO(101) produces a CO2 TPRS peak that is centered at a temperature ~ 50 K lower than the main CO2 TPRS peak arising from CO oxidation on clean PdO(101) (~ 330 vs. 380 K). RAIRS shows that CO continues to adsorb on atop-Pd sites of PdO(101) when H2O is co-adsorbed, and provides no evidence of other reactive intermediates. DFT calculations predict that the CO oxidation mechanism follows the same steps for CO adsorbed on PdO(101) with and without co-adsorbed H2O, wherein an atop-CO species recombines with an oxygen atom from the oxide surface lattice. According to DFT, hydrogen bonding interactions with adsorbed H2O species stabilize the carboxyl-like transition structure and intermediate that result from the initial recombination of CO and O on the PdO(101) surface. This stabilization lowers the energy barrier for CO oxidation on PdO(101) by ~ 10 kJ/mol, in good agreement with our experimental estimate.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2015-03-30

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

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

    Science.gov (United States)

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

    2015-11-01

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

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

    Science.gov (United States)

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

    2015-11-01

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

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

    Energy Technology Data Exchange (ETDEWEB)

    McLeod, Kate [Ian Wark Research Institute, University of South Australia, Mawson Lakes, SA 5095 (Australia); Kumar, Sunil [Ian Wark Research Institute, University of South Australia, Mawson Lakes, SA 5095 (Australia)]. E-mail: sunil.kumar@unisa.edu.au; Smart, Roger St.C. [Applied Centre for Structural and Synchrotron Studies (ACeSSS), University of South Australia, Mawson Lakes, SA 5095 (Australia); Dutta, Naba [Ian Wark Research Institute, University of South Australia, Mawson Lakes, SA 5095 (Australia); Voelcker, Nicolas H. [School of Chemistry, Physics and Earth Sciences, Flinders University, Bedford Park, SA 5042 (Australia); Anderson, Gail I. [Department of Surgery, Flinders Medical Centre, Flinders University, Bedford Park, SA 5042 (Australia); Sekel, Ron [St. George Hospital, Kogarah, Sydney, NSW 2217 (Australia)

    2006-12-30

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

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

    Science.gov (United States)

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

    2006-12-01

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

  6. Adsorption/Desorption Behavior of Water Vapor in an Adsorbent Desiccant Rotor

    Science.gov (United States)

    Tsujiguchi, Takuya; Kodama, Akio

    To clarify the operating and design concept of desiccant rotor, which is a most important component of an adsorptive desiccant cooling process, adsorption / desorption behavior of water vapor in a desiccant rotor has been investigated by means of computer simulation. Mass transfer coefficient in the mathematical model could be related to cycle time by applying the penetration theory. Considering this relationship, influences of the rotation speed of the desiccant rotor, process / regeneration air velocity and their velocity ratio were investigated. It was found that the optimum rotation speed tended to disappear when the regeneration air temperature was low and its humidity was considerably small compared to the process inlet air, since the product air condition approached to regeneration air condition as the rotation speed increased. Decrease of the dehumidifying performance was observed at higher air velocity and the corresponding higher rotation speed since the adsorbent rotor was not fully regenerated due to shorter regeneration time and shorter residence time of process / regeneration air in the adsorbent rotor prevented the mass transfer between air and adsorbent. It was also found that the dehumidifying performance was not improved even though the adsorbent was fully regenerated by higher regeneration air velocity as the sensible heat transferred from the regeneration zone via adsorbent itself increased and disturbed adsorption.

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

    Energy Technology Data Exchange (ETDEWEB)

    Takeda, Hayato; Tamada, Masao; Kasai, Noboru; Katakai, Akio; Hasegawa, Shin; Seko, Noriaki; Sugo, Takanobu [Japan Atomic Energy Research Inst., Takasaki, Gunma (Japan). Takasaki Radiation Chemistry Research Establishment; Onuma, Kenji [Mitsubishi Materials Corp., Tokyo (Japan); Kawabata, Yukiya [Ebara Research Co., Ltd., Fujisawa, Kanagawa (Japan)

    2001-10-01

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

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

    Science.gov (United States)

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

    2015-12-01

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

  9. VALORIZATION AND BIODECOLORIZATION OF DYE ADSORBED ON LIGNOCELLULOSICS USING WHITE ROT FUNGI

    Directory of Open Access Journals (Sweden)

    Nesrin Ozmen,

    2012-02-01

    Full Text Available Biosorption of dyes by lignocelluloses may be an effective method for removing dyes from textile effluents. However, the resulting dye-adsorbed lignocellulosic materials may constitute another pollution problem. An integrated method can solve this problem. Here, various lignocelluloses were tested for their Astrazon Black and Astrazon Blue dyes removal activities. The dye adsorbed after 30 min contact time was 90% (45 mg/L, 70% (35 mg/L, and 98% (49 mg/L for wheat bran, pine cone, and cotton stalk, respectively. These dye-adsorbed lignocellulosic wastes then were used as solid substrates to produce laccase enzyme with Funalia trogii and Trametes versicolor under solid state fermentation (SSF. Among the lignocellulosic substrates, the dye-adsorbed wheat bran served as the best solid substrate for laccase production under SSF. Therefore, it was also tested as a solid source for laccase production under submerged fermentation. During solid state fermentation, these two fungi were able to highly decolorize these dyes. While F. trogii decolorized 80% of Astrazon Black dye adsorbed onto wheat bran, T. versicolor decolorized 86%. On the other hand, the decolorization values for Astrazon Blue dye were 69% and 84%, respectively.

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

    Science.gov (United States)

    Maurer, Reinhard J; Ruiz, Victor G; Tkatchenko, Alexandre

    2015-09-14

    A correct description of electronic exchange and correlation effects for molecules in contact with extended (metal) surfaces is a challenging task for first-principles modeling. In this work, we demonstrate the importance of collective van der Waals dispersion effects beyond the pairwise approximation for organic-inorganic systems on the example of atoms, molecules, and nanostructures adsorbed on metals. We use the recently developed many-body dispersion (MBD) approach in the context of density-functional theory [Tkatchenko et al., Phys. Rev. Lett. 108, 236402 (2012) and Ambrosetti et al., J. Chem. Phys. 140, 18A508 (2014)] and assess its ability to correctly describe the binding of adsorbates on metal surfaces. We briefly review the MBD method and highlight its similarities to quantum-chemical approaches to electron correlation in a quasiparticle picture. In particular, we study the binding properties of xenon, 3,4,9,10-perylene-tetracarboxylic acid, and a graphene sheet adsorbed on the Ag(111) surface. Accounting for MBD effects, we are able to describe changes in the anisotropic polarizability tensor, improve the description of adsorbate vibrations, and correctly capture the adsorbate-surface interaction screening. Comparison to other methods and experiment reveals that inclusion of MBD effects improves adsorption energies and geometries, by reducing the overbinding typically found in pairwise additive dispersion-correction approaches. PMID:26374001

  11. Epoxide-functionalization of polyethyleneimine for synthesis of stable carbon dioxide adsorbent in temperature swing adsorption.

    Science.gov (United States)

    Choi, Woosung; Min, Kyungmin; Kim, Chaehoon; Ko, Young Soo; Jeon, Jae Wan; Seo, Hwimin; Park, Yong-Ki; Choi, Minkee

    2016-01-01

    Amine-containing adsorbents have been extensively investigated for post-combustion carbon dioxide capture due to their ability to chemisorb low-concentration carbon dioxide from a wet flue gas. However, earlier studies have focused primarily on the carbon dioxide uptake of adsorbents, and have not demonstrated effective adsorbent regeneration and long-term stability under such conditions. Here, we report the versatile and scalable synthesis of a functionalized-polyethyleneimine (PEI)/silica adsorbent which simultaneously exhibits a large working capacity (2.2 mmol g(-1)) and long-term stability in a practical temperature swing adsorption process (regeneration under 100% carbon dioxide at 120 °C), enabling the separation of concentrated carbon dioxide. We demonstrate that the functionalization of PEI with 1,2-epoxybutane reduces the heat of adsorption and facilitates carbon dioxide desorption (>99%) during regeneration compared with unmodified PEI (76%). Moreover, the functionalization significantly improves long-term adsorbent stability over repeated temperature swing adsorption cycles due to the suppression of urea formation and oxidative amine degradation. PMID:27572662

  12. INFLUENCE OF ADSORBED AND DISSOLVED CARBOXYMETHYL CELLULOSE ON FIBRE SUSPENSION DISPERSING, DEWATERABILITY, AND FINES RETENTION

    Directory of Open Access Journals (Sweden)

    Henrikki Liimatainen

    2009-02-01

    Full Text Available The effect of adsorbed and soluble carboxymethyl cellulose (CMC on dispersing, dewaterability, and fines retention of pulp fibre suspensions was investigated. CMC was added to a suspension in the presence of electrolytes, causing its adsorption to the fibre surfaces, or to a suspension without electrolytes, so that it stayed in the liquid phase. Both the CMC adsorbed on fibre surfaces and that in the liquid phase were able to disperse the fibre suspension due to the ability of CMC to reduce fibre-to-fibre friction in both phases. Adsorbed CMC promoted the formation of a water-rich microfibrillar gel on the fibre surfaces through the spreading out of microfibrils, leading to a decrease in friction at the fibre-fibre contact points and to the increased dispersion of fibres. CMC in the liquid phase of the suspension was in turn thought to prevent fibre-to-fibre contacts due to the large physical size of the CMC molecules. CMC in both phases had detrimental effects on dewatering of the pulp suspension, but adsorbed CMC caused more plugging of the filter cake, and this was attributed to its ability to disperse fibre fines, in particular. Thus, adsorbed CMC also reduced fines retention considerably more than did CMC in the liquid phase of a suspension.

  13. Enhanced removal of nitrate from water using surface modification of adsorbents--a review.

    Science.gov (United States)

    Loganathan, Paripurnanda; Vigneswaran, Saravanamuthu; Kandasamy, Jaya

    2013-12-15

    Elevated concentration of nitrate results in eutrophication of natural water bodies affecting the aquatic environment and reduces the quality of drinking water. This in turn causes harm to people's health, especially that of infants and livestock. Adsorbents with the high capacity to selectively adsorb nitrate are required to effectively remove nitrate from water. Surface modifications of adsorbents have been reported to enhance their adsorption of nitrate. The major techniques of surface modification are: protonation, impregnation of metals and metal oxides, grafting of amine groups, organic compounds including surfactant coating of aluminosilicate minerals, and heat treatment. This paper reviews current information on these techniques, compares the enhanced nitrate adsorption capacities achieved by the modifications, and the mechanisms of adsorption, and presents advantages and drawbacks of the techniques. Most studies on this subject have been conducted in batch experiments. These studies need to include continuous mode column trials which have more relevance to real operating systems and pilot-plant trials. Reusability of adsorbents is important for economic reasons and practical treatment applications. However, only limited information is available on the regeneration of surface modified adsorbents. PMID:24211565

  14. Physico-chemical properties of biodiesel manufactured from waste frying oil using domestic adsorbents

    Science.gov (United States)

    Ismail, Samir Abd-elmonem A.; Ali, Rehab Farouk M.

    2015-06-01

    We have evaluated the efficiency of sugar cane bagasse ash (SCBA), date palm seed carbon (DPSC), and rice husk ash (RHA) as natural adsorbents and compared them with the synthetic adsorbent Magnesol XL for improving the quality of waste frying oil (WFO) and for the impact on the physicochemical properties of the obtained biodiesel. We measured moisture content, refractive index (RI), density, acid value (AV), iodine value (IV), peroxide value (PV), and saponification value (SV), as well as fatty acid profile. Purification treatments with various levels of adsorbents caused significant (P ≤ 0.05) decreases in free fatty acids (FFAs), PVs, and IVs. The highest yields (86.45 and 87.80%) were observed for biodiesel samples produced from WFO treated with 2% Magnesol and 3% of RHA, respectively, followed by samples treated with 2 and 3% of DPSC or RHA. Pre-treatments caused a significant decrease in the content of C 18:2 linoleic acids, consistent with a significant increase in the content of monounsaturated and saturated fatty acids (MUFA) in the treated samples. The highest oxidation value (COX) (1.30) was observed for biodiesel samples produced from WFO without purification treatments. However, the lowest values (0.44-0.73) were observed for biodiesel samples produced from WFO treated with different levels of adsorbents. Our results indicate that pre-treatments with different levels of adsorbents regenerated the quality of WFO and improved the quality of the obtained biodiesel.

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

    Science.gov (United States)

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

    2015-01-01

    Polyaniline-coated lignin-based adsorbent (PLC) was synthesized and used for uptake of reactive dye eosin yellow (EY) from aqueous solution. The adsorption capability of the adsorbent was found to be more effective than the unmodified adsorbent (LC). In particular, the adsorption capability of the PLC was effective over a wider pH range. This could be owing to its higher point of zero charge, which is more favorable for the uptake of the anionic dye. Adsorption isotherm models suggested a monolayer adsorption was predominant. The mean free energy of adsorption (E(DR)) was found to have values between 8 and 16 kJ mol(-1) which suggests that an electrostatic mechanism of adsorption predominated over other underlying mechanisms. The adsorption process was also found to be spontaneous, with increasing negative free energy values observed at higher temperatures. Chemisorption process was supported by the changes in enthalpy above 40 kJ mol(-1) and by the results of desorption studies. This new adsorbent was also reusable and regenerable over four successive adsorption-desorption cycles. The single stage adsorber design revealed that PLC can be applicable as an effective biosorbent for the treatment of industrial effluents containing EY dye. PMID:25256550

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

    Science.gov (United States)

    Yao, Ye

    2016-07-01

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

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

    International Nuclear Information System (INIS)

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

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2012-05-30

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

  19. Characterization of production of free gluconic acid by Gluconobacter suboxydans adsorbed on ceramic honeycomb monolith.

    Science.gov (United States)

    Shiraishi, F; Kawakami, K; Kono, S; Tamura, A; Tsuruta, S; Kusunoki, K

    1989-05-01

    Gluconobacter suboxydans IFO 3290 was immobilized by adsorption on ceramic honeycomb monolith and continuous production of free gluconic acid from glucose was performed in an aerated reactor. The effects of reactor residence time, aeration rate, and glucose concentration were investigated on the gluconic acid yield. Observation of SEM photographs revealed that the cells were adsorbed with a high density not only on the outer surface of the support but also on the inner surface of large pores. From measurement of the number of the adsorbed cells, it was elucidated that the biofilm comprised a monolayer or bilayer of the cells. Maximum specific rate of growth was estimated for the free and adsorbed cells, and the adsorbed cells were found to grow at a fast rate compared with the free cells. In the continuous fermentation performed for one month at the glucose concentration of 100 kg/m(3), reactor residence time of 3.5 h and aeration rate of 900 cm(3)/min, the activity of the adsorbed cells was appreciably stable. The high productivity of 26.3 kg/(m(3)-reactor . h) was attained with the gluconic acid yield of 84.6% and glucose conversion of 94%.

  20. Competitive and cooperative adsorption behaviors of phenol and aniline onto nonpolar macroreticular adsorbents

    Institute of Scientific and Technical Information of China (English)

    ZHANG Wei-ming; CHEN Jin-long; PAN Bing-cai; ZHANG Quan-xing

    2005-01-01

    The adsorption behaviors of phenol and aniline on nonpolar macroreticular adsorbents( NDA100 and Amberlite XAD4) were investigated in single or binary batch system at 293K and 313K respectively in this study. The results indicated that the adsorption isotherms of phenol and aniline on both adsorbents in both systems fitted well Langmuir equation, which indicated a favourable and exothermic process. At the lower equilibrium concentrations, the individual amount adsorbed of phenol or aniline or macroreticular adsorbents in single-component systems was higher than those in binary-component systems because of the competition between phenol and aniline towards the adsorption sites. It is noteworthy, on the contrast, that at higher concentrations, the total uptake amounts of phenol and aniline in binary-component systems were obviously larger than that in single-component systems, and a large excess was noted on the adsorbent surface at saturation, which is presumably due to the cooperative effect primarily arisen from the hydrogen bonding or weak acidbase interaction between phenol and aniline.

  1. Lead Removal from Aqueous Solutions Using Novel Gel Adsorbent Synthesized from Natural Condensed Tannin

    Institute of Scientific and Technical Information of China (English)

    占新民; 赵璇; AKANEMiyazaki; YOSHIONakano

    2003-01-01

    Lead has caused serious environmental pollution due to its toxicity, accumulation in food chains and persistence in nature. In this paper, removal of lead from aqueous solutions is investigated using a novel gel adsorbent synthesized from natural condensed tannin. The novel adsorbent performs in aqueous solutions as a weak base with valid basic groups of 1.2mmol·g-1 tannin gel particles and therefore results in the elevation of pH value of aqueous solutions. Even when initial pH is 3.6, final pH at equilibrium can climb up to 6.5 that is above the pH value for Pb(OH)2 precipitation formation and then lead can be removed from wastewater by this so-called surface precipitation. The adsorption isotherm can be expressed by the Langmuir equation and the maximum capacity for adsorption of Pb is up to 92mg·g-l(based on dry adsorbent) when initial pH value is 3.6. Hence, the adsorbent does offer favorable properties in lead removal with respect to its high adsorption capacity at low initial pH value,which is advantageous to lead removal from acidic wastewater. A model is put forward to describe the individual adsorption phenomenon of the tannin gel adsorbent.

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

    Science.gov (United States)

    Yao, Ye

    2016-07-01

    The physical mechanisms of heat and mass transfer enhancement by ultrasound have been identified by people. Basically, the effect of 'cavitation' induced by ultrasound is the main reason for the enhancement of heat and mass transfer in a liquid environment, and the acoustic streaming and vibration are the main reasons for that in a gaseous environment. The adsorbent regeneration and food drying/dehydration are typical heat and mass transfer process, and the intensification of the two processes by ultrasound is of complete feasibility. This paper makes an overview on recent studies regarding applications of power ultrasound to adsorbent regeneration and food drying/dehydration. The concerned adsorbents include desiccant materials (typically like silica gel) for air dehumidification and other ones (typically active carbon and polymeric resin) for water treatment. The applications of ultrasound in the regeneration of these adsorbents have been proved to be energy saving. The concerned foods are mostly fruits and vegetables. Although the ultrasonic treatment may cause food degradation or nutrient loss, it can greatly reduce the food processing time and decrease drying temperature. From the literature, it can be seen that the ultrasonic conditions (i.e., acoustic frequency and power levels) are always focused on during the study of ultrasonic applications. The increasing number of relevant studies argues that ultrasound is a very promising technology applied to the adsorbent regeneration and food drying/dehydration. PMID:26964979

  3. Numerical Analysis on Adsorption Characteristics of Activated Carbon/Ethanol Pair in Finned Tube Type Adsorber

    Science.gov (United States)

    Makimoto, Naoya; Kariya, Keishi; Koyama, Shigeru

    The cycle performance of adsorption cooling system depends on the thermophysical properties of the adsorbent/refrigerant pair and configuration of the adsorber/desorber heat exchanger. In this study, a twodimensional analysis is carried out in order to clarify the performance of the finned tube type adsorber/desorber heat exchanger using a highly porous activated carbon powder (ACP)/ethanol pair. The simulation results show that the average cooling capacity per unit volume of adsorber/desorber heat exchanger and coefficient of performance (COP) can be improved by optimizing fin thickness, fin height, fin pitch and tube diameter. The performance of a single stage adsorption cooling system using ACP/ethanol pair is also compared with that of activated carbon fiber (ACF)/ethanol pair. It is found that the cooling capacities of each adsorbent/refrigerant pair increase with the decrease of adsorption/desorption time and the cooling capacity of ACP/ethanol pair is approximately 2.5 times as much as that of ACF/ethanol pair. It is also shown that COP of ACP/ethanol pair is superior to that of ACF/ethanol pair.

  4. Visualization and Measurement of Adsorption/Desorption Process of Ethanol in Activated Carbon Adsorber

    Science.gov (United States)

    Asano, Hitoshi; Murata, Kenta; Takenaka, Nobuyuki; Saito, Yasushi

    Adsorption refrigerator is one of the efficient tools for waste heat recovery, because the system is driven by heat at relative low temperature. However, the coefficient of performance is low due to its batch operation and the heat capacity of the adsorber. In order to improve the performance, it is important to optimize the configuration to minimize the amount of driving heat, and to clarify adsorption/desorption phenomena in transient conditions. Neutron radiography was applied to visualize and measure the adsorption amount distribution in an adsorber. The visualization experiments had been performed at the neutron radiography facility of E-2 port of Kyoto University Research Reactor. Activated carbon and ethanol were used as the adsorbent and refrigerant. From the acquired radiographs, adsorption amount was quantitatively measured by applying the umbra method using a checkered neutron absorber with boron powder. Then, transient adsorption and desorption processes of a rectangular adsorber with 84 mm in width, 50 mm in height and 20 mm in depth were visualized. As the result, the effect of fins in the adsorbent layer on the adsorption amount distribution was clearly visualized.

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

    Science.gov (United States)

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

    2014-09-01

    Four typical types of green shrubs of Beijing (Euonymus japonicus, Buxus microphylla, Berberis thunbergii cv. atropurpurea, Taxus cuspidate cv. nana) were selected to study their capacities in adsorbing and arresting PM2.5 using both field observations and air chamber simulations. Concurrently, in order to analyze the pollution characteristics of Beijing in winter and spring, the PM2.5 concentrations of December 2012 to May 2013 were collected. Experimental results showed that: From the gas chamber experiments, the ability to adsorb and arrest PM2.5 was in the order of Berberis thunbergii cv. atropurpurea > Buxus microphylla > Taxus cuspidate cv. nana > Euonymus japonicus, mainly due to the differences in leaf characteristics; Outside measurement results showed that the ability to adsorb and arrest PM2.5 was ranked as Buxus microphylla > Berberis thunbergii cv. atropurpurea > Taxus cuspidate cv. nana > Euonymus japonicus. Chamber simulation and outdoor observation showed that Buxus microphylla and Berberis thunbergii cv. atropurpurea had strong ability to adsorb and arrest PM2.5; Meanwhile, the slight differences between the chamber simulation and outdoor observation results might be related to plant structure. Compared to tree species, the planting condition of shrub species was loose, and it greened quickly; By analyzing the Beijing PM2.5 concentration values in winter and spring, it was found that the PM2.5 concentration was particularly high in the winter of Beijing, and evergreen shrubs maintained the ability to adsorb and arrest PM2.5. PMID:25518685

  6. Effect of colloidal particle size on adsorbed monodisperse and bidisperse monolayers.

    Science.gov (United States)

    Rosenberg, Rachel T; Dan, Nily

    2011-07-19

    Coating hydrogel films or microspheres by an adsorbed colloidal shell is one synthesis method for forming colloidosomes. The colloidal shell allows control of the release rate of encapsulated materials, as well as selective transport. Previous studies found that the packing density of self-assembled, adsorbed colloidal monolayers is independent of the colloidal particle size. In this paper we develop an equilibrium model that correlates the packing density of charged colloidal particles in an adsorbed shell to the particle dimensions in monodisperse and bidisperse systems. In systems where the molar concentration in solution is fixed, the increase in adsorption energy with increasing particle size leads to a monotonic increase in the monolayer packing density with particle radius. However, in systems where the mass fraction of the particles in the adsorbing solutions is fixed, increasing particle size also reduces the molar concentration of particles in solution, thereby reducing the probability of adsorption. The result is a nonmonotonic dependence of the packing density in the adsorbed layer on the particle radius. In bidisperse monolayers composed of two particle sizes, the packing density in the layer increases significantly with size asymmetry. These results may be utilized to design the properties of colloidal shells and coatings to achieve specific properties such as transport rate and selectivity.

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

    Science.gov (United States)

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

    2015-01-01

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

  8. Synthesis of novel aminated cellulose microsphere adsorbent for efficient Cr(VI) removal

    Science.gov (United States)

    Yu, Tianlin; Liu, Siqi; Xu, Min; Peng, Jing; Li, Jiuqiang; Zhai, Maolin

    2016-08-01

    A novel aminated cellulose microsphere adsorbent (CVN) was successfully prepared by radiation-induced graft polymerization of vinylbenzyl chloride (VBC) onto cellulose microsphere (CMS), followed by amination. Micro-FTIR, XPS and SEM confirmed the structure of CVN. The adsorption behavior of Cr(VI) onto CVN from solution was well fitted by the pseudo-second order kinetic model. The isothermal adsorption of Cr(VI) was observed at pH 4.68 with adsorption capacity of 129 mg/g in accordance with Langmuir thermal model, and the removal of Cr(VI) from solution could be 91% at a low amount (20 mg) of adsorbent. The best pH for adsorption of Cr(VI) was nearly 3.08, and with the increasing of temperature, the adsorption capacity of Cr(VI) increased. XPS analysis confirmed the adsorption mechanism of Cr(VI) was ion-exchange mechanism, while common co-ions such as Na+, Mg2+, Cu2+, Ca2+, Zn2+, Ni2+, Cl-, NO3- has no significant effect on the adsorption capacity of Cr(VI), and the Cr(VI) removal of 80% still could be obtained compared with that of fresh CVN adsorbent. Finally, spent CVN could be regenerated under 2 mol/L NaCl. The work indicated that aminated cellulose adsorbent could be prepared successfully by radiation-induced grafting and amination and CVN is a promising bio-adsorbent in the removing Cr(VI) from waste water.

  9. PVDF membranes containing hybrid nanoparticles for adsorbing cationic dyes: physical insights and mechanism

    Science.gov (United States)

    Sharma, Maya; Madras, Giridhar; Bose, Suryasarathi

    2016-07-01

    In this study, Fe (iron) and Ag (silver) based adsorbents were synthesized using solution combustion and in situ reduction techniques. The synthesized adsorbents were comprehensively characterized by different techniques including electron microscopy, BET, XRD, Zeta potential etc. Three chlorinated cationic dyes used were malachite green, methyl violet and pyronin Y. These dyes were adsorbed on various synthesized adsorbents [iron III oxide (Fe2O3)], iron III oxide decorated silver nanoparticles by combustion synthesis technique [Fe2O3–Ag(C)] and iron III oxide decorated silver nanoparticles using in situ reduction, [Fe2O3–Ag (S)]. The isotherm and the adsorption kinetics have been studied systematically. The kinetic data can be explained by the pseudo second order model and the adsorption equilibrium followed Langmuir isotherm. The equilibrium and kinetics results suggest that Fe2O3–Ag(S) nanoparticles showed the maximum adsorption among all the adsorbents. Hence, Polyvinylidene fluoride based membranes containing Fe2O3–Ag(S) nanoparticles were prepared via phase inversion (precipitation immersion using DMF/water) technique. The adsorption kinetics were studied in detail and it was observed that the composite membrane showed synergistic improvement in dye adsorption. Such membranes can be used for water purification.

  10. Fiber-based adsorbents having high adsorption capacities for recovering dissolved metals and methods thereof

    Energy Technology Data Exchange (ETDEWEB)

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

    2016-09-06

    A fiber-based adsorbent and a related method of manufacture are provided. The fiber-based adsorbent includes polymer fibers with grafted side chains and an increased surface area per unit weight over known fibers to increase the adsorption of dissolved metals, for example uranium, from aqueous solutions. The polymer fibers include a circular morphology in some embodiments, having a mean diameter of less than 15 microns, optionally less than about 1 micron. In other embodiments, the polymer fibers include a non-circular morphology, optionally defining multiple gear-shaped, winged-shaped or lobe-shaped projections along the length of the polymer fibers. A method for forming the fiber-based adsorbents includes irradiating high surface area polymer fibers, grafting with polymerizable reactive monomers, reacting the grafted fibers with hydroxylamine, and conditioning with an alkaline solution. High surface area fiber-based adsorbents formed according to the present method demonstrated a significantly improved uranium adsorption capacity per unit weight over existing adsorbents.

  11. Design approaches for a cycling adsorbent/photocatalyst system for indoor air purification: formaldehyde example.

    Science.gov (United States)

    Chin, Paul; Ollis, David F

    2008-04-01

    A kinetic model for a cycling adsorbent/photocatalyst combination for formaldehyde removal in indoor air (Chin et al. J. Catalysis 2006, 237, 29-37) was previously developed in our lab, demonstrating agreement with lab-scale batch operation data of other researchers (Shiraishi et al. Chem. Engineer. Sci. 2003, 58, 929-934). Model parameters evaluated included adsorption equilibrium and rate constants for the adsorbent (activated carbon) honeycomb rotor, and catalytic rate constant for pseudo-first-order formaldehyde destruction in the titanium dioxide photoreactor. This paper explores design consequences for this novel system. In particular, the batch parameter values are used to model both adsorbent and photocatalyst behavior for continuous operation in typical residential home challenges. Design variables, including realistic make-up air fraction, adsorbent honeycomb rotation speed, and formaldehyde source emission rate, are considered to evaluate the ability of the system to achieve World Health Organization pollutant guidelines. In all circumstances, the size of the required rotating adsorbent bed and photoreactor for single-stage operation and the resultant formaldehyde concentration in the home are calculated. The ability of how well such a system might be accommodated within the typical dimensions of commercial ventilation ducts is also considered.

  12. Graphene nanosheets and graphite oxide as promising adsorbents for removal of organic contaminants from aqueous solution.

    Science.gov (United States)

    Ji, Liangliang; Chen, Wei; Xu, Zhaoyi; Zheng, Shourong; Zhu, Dongqiang

    2013-01-01

    Graphenes are an emerging class of carbon nanomaterials whose adsorption properties toward organic compounds have not been well understood. In the present study, graphene nanosheets were prepared by reoxidation and abrupt heating of graphite oxide, which was prepared by sequential chemical oxidation of commercial nonporous graphite powder. Adsorption properties of three aromatic compounds (naphthalene, 2-naphthol, and 1-naphthylamine) and one pharmaceutical compound (tylosin) on graphene nanosheets and graphite oxide were examined to explore the potential of these two adsorbents for the removal of organic contaminants from aqueous solutions. Compared with the literature data of adsorption on carbon nanotubes, adsorption of bulky, flexible tylosin on graphene nanosheets exhibited markedly faster adsorption kinetics, which can be attributed to their opened-up layer structure. Graphene nanosheets and graphite oxide showed similar sequences of adsorption affinity: 1-naphthylamine > 2-naphthol > tylosin > naphthalene (with much larger differences observed on graphite oxide). It was proposed that the strong adsorption of the three aromatic compounds was mainly due to π-π electron donor-acceptor interactions with the graphitic surfaces of adsorbents. Additionally, Lewis acid-base interaction was likely an important factor contributing to the strong adsorption of 1-naphthylamine and tylosin, especially for the O-functionality-abundant graphite oxide. After being normalized on the basis of adsorbent surface area, adsorption affinities of all four tested adsorbates on graphene nanosheets were very close to those on nonporous graphite powder, reflecting complete accessibility of the adsorbent surface area in adsorption.

  13. Epoxide-functionalization of polyethyleneimine for synthesis of stable carbon dioxide adsorbent in temperature swing adsorption

    Science.gov (United States)

    Choi, Woosung; Min, Kyungmin; Kim, Chaehoon; Ko, Young Soo; Jeon, Jae Wan; Seo, Hwimin; Park, Yong-Ki; Choi, Minkee

    2016-08-01

    Amine-containing adsorbents have been extensively investigated for post-combustion carbon dioxide capture due to their ability to chemisorb low-concentration carbon dioxide from a wet flue gas. However, earlier studies have focused primarily on the carbon dioxide uptake of adsorbents, and have not demonstrated effective adsorbent regeneration and long-term stability under such conditions. Here, we report the versatile and scalable synthesis of a functionalized-polyethyleneimine (PEI)/silica adsorbent which simultaneously exhibits a large working capacity (2.2 mmol g-1) and long-term stability in a practical temperature swing adsorption process (regeneration under 100% carbon dioxide at 120 °C), enabling the separation of concentrated carbon dioxide. We demonstrate that the functionalization of PEI with 1,2-epoxybutane reduces the heat of adsorption and facilitates carbon dioxide desorption (>99%) during regeneration compared with unmodified PEI (76%). Moreover, the functionalization significantly improves long-term adsorbent stability over repeated temperature swing adsorption cycles due to the suppression of urea formation and oxidative amine degradation.

  14. Removal of cationic dyes from aqueous solution using magnetic multi-wall carbon nanotube nanocomposite as adsorbent

    International Nuclear Information System (INIS)

    A magnetic multi-wall carbon nanotube (MMWCNT) nanocomposite was synthesized and was used as an adsorbent for removal of cationic dyes from aqueous solutions. The MMWCNT nanocomposite was composed of commercial multi-wall carbon nanotubes and iron oxide nanoparticles. The properties of this magnetic adsorbent were characterized by scanning electron microscopy, X-ray diffraction and BET surface area measurements. Adsorption characteristics of the MMWCNT nanocomposite adsorbent were examined using methylene blue, neutral red and brilliant cresyl blue as adsorbates. Experiments were carried out to investigate adsorption kinetics, adsorption capacity of the adsorbent and the effect of adsorption dosage and solution pH values on the removal of cationic dyes. Kinetic data were well fitted by a pseudo second-order model. Freundlich model was used to study the adsorption isotherms. The prepared MMWCNT adsorbent displayed the main advantage of separation convenience compared to the present adsorption treatment.

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

    DEFF Research Database (Denmark)

    Zhang, Ge; He, Wenna; Fang, Lei;

    2013-01-01

    The transfer mechanism of volatile organic compounds (VOCs) being trapped inside the various types of adsorbents is usually regarded as mere diffusion. This paper investigated the contribution of convective mass transfer inside the adsorbents used for VOC air-cleaning. The adsorbents are typically...... characterized by their high porosity and thickness which can be as thin as hundreds of microns. By numerical simulation, it was found that the air flow could penetrate the adsorbent matrix when the porosity was high. When the porosity is about 0.7 or even higher, the velocity profile inside the adsorbent...... and cavity would form, approximately, a consecutive parabola. The convective mass transfer inside the adsorbents would have little impact on the axial VOC transfer but could affect the average adsorption rate significantly at high porosities. The Peclet number Pe which is based on the inlet velocity...

  16. Application of insoluble tannin adsorbent to alpha aqueous waste treatment in NUCEF

    International Nuclear Information System (INIS)

    The use of insoluble tannin adsorbent has been investigated as a means to reduce the volume of aqueous waste contaminated with americium. This work is aimed at reducing the volume of TRU waste generated within NUCEF where experiments related to back end of the nuclear fuel cycle are performed. Insoluble tannin adsorbent is a gelled material consisting of C, H and O which can be easily incinerated. The distribution coefficient and adsorption capacity of americium in insoluble tannin have been investigated and found to be 1000 ml/g in 0.02 M HNO3 and 0.013 mmol/g-dried tannin, respectively. The prospect of applying the adsorbent to the treatment of aqueous waste contaminated with americium appears promising. (author)

  17. Hard coal as a potential low-cost adsorbent for removal of 4-chlorophenol from water.

    Science.gov (United States)

    Kuśmierek, Krzysztof; Zarębska, Katarzyna; Świątkowski, Andrzej

    2016-01-01

    The potential use of raw hard coals as low-cost adsorbents for the removal of 4-chlorophenol (4-CP) from aqueous solutions was examined. The effect of experimental parameters such as the pH and salt presence was evaluated. The kinetic studies showed the equilibrium time was found to be 2 h for all of the adsorbents and that the adsorption process followed the pseudo-second order kinetic model. The adsorption isotherms of the 4-CP on the hard coals were fitted to the Langmuir, Freundlich, Langmuir-Freundlich, Sips and Redlich-Peterson equations. Based on the results obtained, hard coals appear to be a promising adsorbent for the removal of some hazardous water pollutants, like 4-CP and related compounds. PMID:27120657

  18. Removal of Indigo Carmine Dye from Aqueous Solution Using Magnesium Hydroxide as an Adsorbent

    Directory of Open Access Journals (Sweden)

    Thimmasandra Narayan Ramesh

    2015-01-01

    Full Text Available Magnesium hydroxide is used as an adsorbent for the removal of indigo carmine dye from aqueous solution. We have investigated the effectiveness of removal of indigo carmine dye from aqueous solutions at pH 6-7 and 12-13 using magnesium hydroxide thereby varying the dose of the adsorbent, concentration of the dye, duration, and temperature. Structural transformations of adsorbent during the adsorption process at different pH values are monitored using powder X-ray diffraction and infrared spectroscopy. Different types of adsorption isotherm models were evaluated and it was found that Langmuir isotherm fits well at both pH values (6-7 and 12-13. Adsorption of indigo carmine onto magnesium hydroxide at pH 6-7/pH 12-13 follows pseudo-second order rate kinetics.

  19. Application of magnetic particles modified with amino groups to adsorb copper ions in aqueous solution

    Institute of Scientific and Technical Information of China (English)

    Yafen Lin; Huawei Chen; Kaelong Lin; Boryann Chen; Chyowsan Chiou

    2011-01-01

    A magnetic adsorbent can be easily recovered from treated water by magnetic force, without requiring further downstream treatment.In this research, amine-functionalized silica magnetite has been synthesized using N-[3-(trimethoxysilyl)propyl]-ethylenediamine (TPED) as a surface modification agent.The synthesized magnetic amine adsorbents were used to adsorb copper ions in an aqueous solution in a batch system, and the maximum adsorption was found to occur at pH 5.5 ± 0.1.The adsorption equilibrium data fitted the Langmuir isotherm equation reasonably well, with a maximum adsorption capacity of 10.41 mg/g.A pseudo second-order model could best describe the adsorption kinetics, and the derived activation energy was 26.92 kJ/mol.The optimum condition to desorb Cu2+ from NH2/SiO2/Fe3O4 was provided by a solution with 0.1 mol/L HNO3.

  20. Melatonin Nanoparticles Adsorbed to Polyethylene Glycol Microspheres as Activators of Human Colostrum Macrophages

    International Nuclear Information System (INIS)

    The effectiveness of hormones associated with polymeric matrices has amplified the possibility of obtaining new drugs to activate the immune system. Melatonin has been reported as an important immunomodulatory agent that can improve many cell activation processes. It is possible that the association of melatonin with polymers could influence its effects on cellular function. Thus, this study verified the adsorption of the hormone melatonin to polyethylene glycol (PEG) microspheres and analyzed its ability to modulate the functional activity of human colostrum phagocytes. Fluorescence microscopy and flow cytometry analyses revealed that melatonin was able to adsorb to the PEG microspheres. This system increased the release of superoxide and intracellular calcium. There was an increase of phagocytic and microbicidal activity by colostrum phagocytes when in the presence of melatonin adsorbed to PEG microspheres. The modified delivery of melatonin adsorbed to PEG microspheres may be an additional mechanism for its microbicidal activity and represents an important potential treatment for gastrointestinal infections of newborns.

  1. Synthesis of Novel Chelating Adsorbents for Boron Uptake from Aqueous Solutions

    Institute of Scientific and Technical Information of China (English)

    王丽那; 齐涛; 张懿

    2006-01-01

    Two kinds of novel chelating adsorbents have been synthesized to separate boron from aqueous solutions. One is the boron-specific chelating resin, synthesized by the functionalization of macroporous poly (glycidyl methacrylate-cotrimethylolpropane trimethacrylate), with N-methylglucamine. The other is the organic-inorganic hybrid mesoporous SBA-15 with polyol functional groups, prepared by a two-step post-grafting method. The resin can adsorb boron in almost all pH range, and its maximum uptake capacity reaches 1.15 mmol/g. The present study of the polyol-functionalized SBA-15 shows that the post-grafting is successful and the resulting adsorbent has the uptake capacity of 0.63 mmol/g.

  2. Preparation of Ammonia Adsorbent by Carbonizing and Activating Mixture of Biomass Material and Hygroscopic Salt

    Institute of Scientific and Technical Information of China (English)

    LONG Zhen; BU Xianbiao; LU Zhenneng; LI Huashan; MA Weibin

    2015-01-01

    We put forward a new and ingenious method for the preparation of a new adsorbent by soaking, carbonizing and activating the mixture of hygroscopic salt and biomass material. The new adsorbent has high porosity, uniform distribution and high content of CaCl2, and exhibits high adsorption performance. The ammonia uptake and specific cooling power (SCP) at 5 min adsorption time can reach as high as 0.19 g•g-1 and 793.9 W•kg-1, respectively. The concept of utilizing the biomass materials and hygroscopic salts as raw materials for the preparation of adsorbents is of practical interest with respect to the potential quantity of biomass materials around the world, indicating that there would be a new market for biomass materials.

  3. Removal of Anionic Metal Ions from Wastewater by Hydroxide-type Adsorbents

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    Generally speaking, anionic metal concentrations in wastewater from industries and mineral processing plants are well above the allowed limits for effluent set by the Ministry of Environment of Japan. Nowadays, the removal of anionic ions has been considered difficult and development of new process is desperately needed. In this paper, we report the development of three hydroxide-type adsorbents, illustrating their adsorption efficiency in removing As, Se, Mo and Sb ions from aqueous solutions. The main finding of this work was that the adsorption behavior was influenced very much by both the pH and the adsorbent concentration. Nevertheless, the newly developed hydroxide-type adsorbents were very effective in reducing the concentration of those anionic ions.

  4. Adsorption of cyclic hydrocarbons on Pt and the interaction of the adsorbed species with hydrogen

    International Nuclear Information System (INIS)

    The adsorption of six-membered hydrocarbon cycles and cyclopentane and the interaction of hydrogen with the adsorbed layer on polycrystalline Pt-foil have been studied. The work function change (Δφ) was followed by a Kelvin probe and the C/Pt peak ratio was determined by Auger electron spectroscopy. Combining these two techniques made it possible to distinguish between chemisorption via σ-bonds and π-complex formation. Benzene and toluene adsorbed first as π-complex while cyclohexane showed initially a partial aromatization and a π-complex-like bonding to the surface. Excess hydrocarbon or addition of hydrogen transformed the π-complex into σ-bonded species. Cyclopentane adsorbed via σ-bonds and showed no significant hydrogen effect

  5. Removal of basic dye from aqueous solutions using nano scale zero valent iron (NZVI) as adsorbent

    International Nuclear Information System (INIS)

    Nano scale zero valent iron (NZVI) was synthesized and tested for the purification of waste water contaminated by the organic pollutants. In the present study removal of basic blue 3 dye was investigated by NZVI adsorbent. NZVI adsorbent was prepared in the presence of N/sub 2/ gas atmosphere by sodium boro- hydrate (NaHB/sub 4/) reduction method. The particle size of the prepared adsorbent was approximately in the range of 1 x 10/sup -2/nm to 2 x 10/sup -2/nm. The adsorption of basic blue 3 dyes was confirmed with various parameters such as ionic strength, contact time and initial dye concentrations. The experiments were carried out in a batch mode technique. The surface morphology was studied by SEM analysis technique. (author)

  6. Tuberose sticks as an adsorbent in the removal of methylene blue from aqueous solution

    International Nuclear Information System (INIS)

    The use of low-cost and ecofriendly adsorbents has been investigated as an ideal alternative to the current expensive methods of removing dyes from wastewater. Methylene Blue was used as model compound. The effects of contact time, initial dye concentration (20, 30, 40, 50 mg/L), pH and adsorbent dosages have been studied at 25 C. The equilibrium time was found to be 30 min for all the dye concentrations. A maximum removal of 80% was obtained at pH 11.0 for an adsorbent dose 50 mg/50 mL of 40 mg/L dye concentration. Adsorption increased with increase in pH. Maximum desorption of 50% was achieved in water medium at pH 2.0. (author)

  7. Experimental and theoretical studies of L-cysteine adsorbed at Ag(1 1 1) electrodes

    Energy Technology Data Exchange (ETDEWEB)

    Santos, E.; Avalle, L. [Facultad de Matematica, Astronomia y Fisica, Universidad Nacional de Cordoba, 5000 Cordoba (Argentina); Poetting, K.; Jones, H. [University of Ulm, 89069 Ulm (Germany); Velez, P. [Facultad de Ciencias Quimicas, Universidad Nacional de Cordoba, 5000 Cordoba (Argentina)

    2008-10-01

    We have investigated L-cysteine adsorbed on Ag(1 1 1) electrodes under different conditions. We have employed experimental and theoretical approaches to obtain a better understanding of the adsorbed layer. An estimation of the coverage from charge measurements and the second harmonic response shows C{sub 3v} symmetry for the interface indicating a ({radical}3 x {radical}3)R 30 overlayer. The theoretical calculations show a variety of different structures with local adsorption energy minima. Particularly, under special initial conditions, zwitterionic structures adsorbed at different sites have been found. This can account for the multiplicity of redox processes observed experimentally below the potential of zero charge. The presence of an external field produces the stabilization of the zwitterion by interaction of the amino/carboxylic groups with the substrate. (author)

  8. Novel Non-Conventional Adsorbent for the Remediation of Dye Bearing Wastewater

    Directory of Open Access Journals (Sweden)

    Srinivasan Pachamuthu

    2015-07-01

    Full Text Available An adsorbent prepared from an agricultural waste was studied for its efficiency in removal colour. The process parameters were analyzed like agitation time, initial dye concentration, adsorbent dose, pH and temperature. The adsorption mechanism followed pseudo-first order rate expression and the rate is mainly controlled by intra-particle diffusion. The monolayer adsorption capacity obtained from the Langmuir isotherm plot found to be around 45 mg/g at an initial pH 8, the thermodynamic studies show that the adsorption is spontaneous and endothermic in nature, which was indicated by the negative value of free energy change and positive value of enthalpy change. This study proves that novel activated carbon is a promising adsorbent for remediation of textile effluent in a sustainable manner.

  9. Quantitative analysis of Cu and Co adsorbed on fish bones via laser-induced breakdown spectroscopy

    Science.gov (United States)

    Rezk, R. A.; Galmed, A. H.; Abdelkreem, M.; Ghany, N. A. Abdel; Harith, M. A.

    2016-09-01

    In the present work, laser-induced breakdown spectroscopy (LIBS) has been applied for qualitative and quantitative analysis of heavy metals adsorbed by fish bones. Fish bones were used as a natural and low cost heavy metal sorbent (mainly Cu and Co) from synthetic wastewater. The removal efficiency of the adsorbent was studied as a function of initial metal concentration and pH value. Optimal experimental conditions were evaluated for improving the sensitivity of LIBS technique through parametric dependence studies. Furthermore, calibration curves were constructed based on X-ray fluorescence (XRF) analysis technique, whereas, the limits of detection (LOD) for Cu and Co were calculated. The results were validated by comparing LIBS data with those obtained by XRF spectrometry. The results of the two techniques are strongly correlated which verified the feasibility of using LIBS to detect traces of heavy metals adsorbed from wastewater by fish bones. This study reflects the potential of using LIBS in environmental applications.

  10. Study on preparation of a vovel silica adsorbent and its selective separation applied to genistein

    Directory of Open Access Journals (Sweden)

    Yuqing Zhang

    2008-03-01

    Full Text Available In order to selectively separate genistein from its crude solution, a novel silica adsorbent was prepared using genistein as the template molecule, gamma-aminopropylthriethoxysilane as the functional monomer and tetraethyl orthosilicate as the cross-linker. It was analyzed by the BET, FTIR, TEM characteristics, the static adsorption experiment, and selective adsorption experiment. The results show that the silica adsorbent has high specific area, special selectivity and high adsorption capacity for genistein. It can recognize and bind genistein in aqueous solution, and lots of nanopores distribute on its surface uniformly. It is concluded that both the shape and size of the recognition sites matching the template molecule result in the performance of this adsorbent to bind genistein and that there are strong ionic and hydrogen bond attractions between the phenolic hydroxyl and the -NH2.

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

    Science.gov (United States)

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

    1982-01-01

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

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2016-01-27

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

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

    International Nuclear Information System (INIS)

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

  14. Effect of Aluminum Source on Adsorption Performance of Lithium Orthosilicate Based Adsorbents from Kaolin Clay

    Institute of Scientific and Technical Information of China (English)

    XIE Hongyan; DING Tong; LI Yulong; MA Zhi; CHEN Weiqiang

    2015-01-01

    A novel lithium orthosilicate based adsorbent doping with halloysite nanotubes (HNTs) was synthesized with Kaolin clay and SiO2 by an impregnation-precipitation method. The samples were characterized by X-ray diffraction and scanning electron microscopy, nitrogen adsorption-desorption isotherm analysis and thermo-gravimetry, respectively. The results indicate that the reactivity of Li4SiO4 for CO2 absorption can be enhanced by doping alumina. Different alu-minum sources result in different degrees of the CO2 adsorption performance. It is also found that the CO2 capture amount of the adsorbent doping with Halloysite nanotubes is 15.25wt.% at 560℃, which is better than that of the ad-sorbent doping withγ-Al2O3(i.e., 10.88wt.%).

  15. The Use of Amberlite Adsorbents for Green Chromatography Determination of Volatile Organic Compounds in Air

    Directory of Open Access Journals (Sweden)

    Luis Juan-Peiró

    2012-01-01

    Full Text Available Passive samplers have been widely used for volatile organic compounds determination. Following the green chemistry tendency of the direct determination of adsorbed compounds in membrane-based devices through using head space direct chromatography analysis, this work has evaluated the use of Amberlite XAD-2, XAD-4, and XAD-16 adsorbents as a filling material for passive samplers. Direct analysis of the membranes by HS-GC-MS involves a solvent-free method avoiding any sample treatment. For exposed membranes, recoveries ranged from 10% to 203%, depending on the compound and adsorbent used. The limit of the detection values ranged from 1 to 140 ng per sampler. Acceptable precision and sensitivity levels were obtained for the XAD resins assayed.

  16. Decontamination of a radioactive process waste water by adsorbing colloid flotation

    International Nuclear Information System (INIS)

    As a part of a research programme on the treatment of a radioactive process waste water by foam separation techniques, adsorbing colloid flotation was tested to remove 144Ce, 60Co, 65Zn and 89Sr from the waste water. Potassium oleate was used as the collector, and Fe(III) hydroxide, Al(III) hydroxide or Co(II) hydroxide as the coprecipitant. Under the optimal conditions; removals exceeding 99% could be achieved for 65Zn with any of the tested coprecipitants, for 144Ce with Fe(III) and Co(II) hydroxides and for 60Co with only Co(II) hydroxide. For 89Sr removals > 90% could be achieved with only Fe(III) hydroxide. The adsorbing colloid flotation process was compared with both chemical precipitation and ion exchange, and advantages of adsorbing colloid flotation were enumerated. (author)

  17. Removal of lead from aqueous solutions by condensed tannin gel adsorbent

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    Lead has caused serious environmental pollution due toits toxicity, accumulation in food chains and persistence innature. In this paper, lead removal from aqueous solutions wasinvestigated using condensed tannin gel adsorbent synthesized froma natural tannin compound. It is found that the adsorption isstrongly affected by pH values of aqueous solutions. Within pHrange of 3.5-6, when initial lead concentration is 100 mg/L,removal efficiency is more than 90%. Adsorption equilibrium isreached within 150 minutes. The adsorption isotherm fits well withthe Langmuir equation, by which the saturated adsorption uptake of190 mg Pb2+/g dry tannin gel adsorbent is obtained. By means of thermodynamics analysis, it is revealed that the process isexothermic and the adsorption heat is up to 38.4 kJ/mol. Withrespect to high efficiency, moderate pH requirement and minimizedsecond pollution, the tannin gel adsorbent exhibits a promisingpotential in the removal of lead from wastewater.

  18. Preparation of metal adsorbent from poly(methyl acrylate)-grafted-cassava starch via gamma irradiation

    Science.gov (United States)

    Suwanmala, Phiriyatorn; Hemvichian, Kasinee; Hoshina, Hiroyuki; Srinuttrakul, Wannee; Seko, Noriaki

    2012-08-01

    Metal adsorbent containing hydroxamic acid groups was successfully synthesized by radiation-induced graft copolymerization of methyl acrylate (MA) onto cassava starch. The optimum conditions for grafting were studied in terms of % degree of grafting (Dg). Conversion of the ester groups present in poly(methyl acrylate)-grafted-cassava starch copolymer into hydroxamic acid was carried out by treatment with hydroxylamine (HA) in the presence of alkaline solution. The maximum percentage conversion of the ester groups of the grafted copolymer, % Dg=191 (7.63 mmol/g of MA), into the hydroxamic groups was 70% (5.35 mmol/g of MA) at the optimum condition. The adsorbent of 191%Dg had total adsorption capacities of 2.6, 1.46, 1.36, 1.15 and 1.6 mmol/g-adsorbent for Cd2+, Al3+, UO22+, V5+ and Pb2+, respectively, in the batch mode adsorption.

  19. On-surface magnetochemistry: controlling spins in adsorbed molecules by a chemical switch

    International Nuclear Information System (INIS)

    Full text: We are interested in controlling the magnetic properties of paramagnetic molecules adsorbed on ferromagnetic substrates. The transition-metal ions in the surface-adsorbed porphyrins / phthalocyanines have a free top site for an additional ligand to bind and to control the magnetic properties of the on-surface complex. We show switching-off, tuning and switching-on the magnetic moments in the adsorbed complexes. Because of the interaction with the surface, the exact outcome of those reactions can be different. The axial-ligand allows to modify this interaction and can thus be used to control the exchange-interaction with the substrate. We combine element specific x-ray magnetic circular dichroism (XMCD) with STM and DFT+U. (author)

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

    DEFF Research Database (Denmark)

    Vives, E.; Lindgård, P.-A.

    1993-01-01

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

  1. NOX Reduction Using an Electrochemical Cell with NOX adsorbents

    DEFF Research Database (Denmark)

    Shao, Jing

    -Pt-Al2O3 adsorption layer. The effects of the NOx adsorbents on the electrode processes were characterized by electrochemical impedance spectroscopy (EIS). The impedance analysis revealed that the NOx adsorbents greatly enhanced the electrode activity, mainly contributed by the promotion of adsorption......This thesis studied the electrochemical cells modified by NOx adsorbents for the NOx reduction under O2-rich conditions. The structure of a multilayer electrochemical cell with a NOx adsorption layer was optimized by removing a yttria-stabilized zirconia (YSZ) cover layer coated on a Pt....../Ni/YSZ electrode. It was found that the NOx removal properties of the electrochemical cell were dramatically enhanced through this optimization, which was attributed to the extensive release of selective reaction sites for NOx species and a strong promotion for NOx reduction from the interaction of the directly...

  2. Investigation of Performances and Mechanism of Fluoride Removal by Fe(Ⅲ)-Loaded Ligand Exchange Cotton Cellulose Adsorbent

    Institute of Scientific and Technical Information of China (English)

    ZHAO Ya-ping; LI Xiu-yan; LIU Lu; CHEN Fu-hua

    2005-01-01

    Novel adsorbent, Fe( Ⅲ )-loaded ligand exchange cotton cellulose adsorbent [Fe(Ⅲ)LECCA], was used to investigate the adsorption performances and mechanism of fluoride removal from aqueous solutions. The adsorbent was found to adsorb fluoride rapidly and effectively. The fluoride removal was influenced by pH. Adsorption mode followed first-order reaction at different temperature, theapparent adsorption maximal integer coordination ratio of fluoride with Fe (Ⅲ)LECCA was 3: 1. The ligand exchange mechanism of adsorption was elucidated through chemical methods and IR spectral analysis.

  3. Adsorbents made from waste ashes and post-consumer PET and their potential utilization in wastewater treatment.

    Science.gov (United States)

    Zhang, Fu-Shen; Itoh, Hideaki

    2003-08-01

    This study was carried out to prepare low-cost adsorbents from different types of waste ashes and post-consumer PET for use in industrial wastewater treatment. PET was melted and blended with ashes. The mixture was then carbonized to form different types of adsorbents. Heavy metal leaching from the adsorbents was greatly reduced compared to leaching from the bulk ashes. The BET surface area of the adsorbents ranged from 115 to 485m(2)/g. The acidic sites on the adsorbents varied from 0.84 to 1.56meq./g, higher than that of the PET carbon. The adsorption of methylene blue (MB) or heavy metals on the adsorbents was not in accordance with their surface areas because acidic sites reaction, affinity adsorption and cation exchange all contribute to the adsorption of the adsorbents. The isotherm for MB adsorption on the adsorbents can be well described by the Langmuir or Freundlich equation but heavy metal adsorption cannot. It is believed that the adsorbents produced in this manner can be used in wastewater treatments for discoloration and heavy metal removal. PMID:12935763

  4. Comparison of adsorbents for H2S and D4 removal for biogas conversion in a solid oxide fuel cell.

    Science.gov (United States)

    Sigot, Léa; Ducom, Gaëlle; Benadda, Belkacem; Labouré, Claire

    2016-01-01

    Biogas contains trace compounds detrimental for solid oxide fuel cell (SOFC) application, especially sulphur-containing compounds and volatile organic silicon compounds (VOSiCs). It is therefore necessary to remove these impurities from the biogas for fuelling an SOFC. In this paper, dynamic lab-scale adsorption tests were performed on synthetic polluted gas to evaluate the performance of a polishing treatment to remove hydrogen sulphide (H2S - sulphur compound) and octamethylcyclotetrasiloxane (D4 - VOSiC). Three kinds of adsorbents were tested: an activated carbon, a silica gel (SG) and a zeolite (Z). Z proved to be the best adsorbent for H2S removal, with an adsorbed quantity higher than [Formula: see text] at the SOFC tolerance limit. However, as concerns D4 removal, SG was the most efficient adsorbent, with an adsorbed quantity of about 184 mgD4/gSG at the SOFC tolerance limit. These results could not be explained by structural characteristics of the adsorbents, but they were partly explained by chemical interactions between the adsorbate and the adsorbent. In these experiments, internal diffusion was the controlling step, Knudsen diffusion being predominant to molecular diffusion. As Z was also a good adsorbent for D4 removal, competition phenomena were investigated with Z for the simultaneous removal of H2S and D4. It was shown that H2S retention was dramatically decreased in the presence of D4, probably due to D4 polymerization resulting in pore blocking.

  5. Adsorbents made from waste ashes and post-consumer PET and their potential utilization in wastewater treatment.

    Science.gov (United States)

    Zhang, Fu-Shen; Itoh, Hideaki

    2003-08-01

    This study was carried out to prepare low-cost adsorbents from different types of waste ashes and post-consumer PET for use in industrial wastewater treatment. PET was melted and blended with ashes. The mixture was then carbonized to form different types of adsorbents. Heavy metal leaching from the adsorbents was greatly reduced compared to leaching from the bulk ashes. The BET surface area of the adsorbents ranged from 115 to 485m(2)/g. The acidic sites on the adsorbents varied from 0.84 to 1.56meq./g, higher than that of the PET carbon. The adsorption of methylene blue (MB) or heavy metals on the adsorbents was not in accordance with their surface areas because acidic sites reaction, affinity adsorption and cation exchange all contribute to the adsorption of the adsorbents. The isotherm for MB adsorption on the adsorbents can be well described by the Langmuir or Freundlich equation but heavy metal adsorption cannot. It is believed that the adsorbents produced in this manner can be used in wastewater treatments for discoloration and heavy metal removal.

  6. To-date spacecraft applications and demonstration testing results, and future product development for new molecular adsorber technologies

    Science.gov (United States)

    Thomson, Shaun; Hansen, Patricia; Straka, Sharon; Chen, Philip; Triolo, Jack; Bettini, Ron; Carosso, Paolo; Carosso, Nancy

    1997-01-01

    The use of molecular adsorbers, in order to aid in the reduction of the spacecraft contamination levels, is discussed. Molecular adsorbers are characterized by an extremely large surface area, molecularly-porous substructure, and processing charged sites capable of retaining molecular contaminant species. Molecular adsorbers were applied on two Hubble Space Telescope servicing missions, as well as on the tropical rainfall measuring mission. The use of molecular adsorbers carries the potential for low cost, easy fabrication and integration of reliable means for reducing the contamination level around spacecraft.

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

    Energy Technology Data Exchange (ETDEWEB)

    Marano, M.; Torreiro, Y.

    2014-02-01

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

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

    Science.gov (United States)

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

    2016-05-01

    Purification of virus-like particles (VLPs) in bind-and-elute mode has reached a bottleneck. Negative chromatography has emerged as the alternative solution; however, benchmark of negative chromatography media and their respective optimized conditions are absent. Hence, this study was carried out to compare the performance of different negative chromatography media for the purification of hepatitis B VLPs (HB-VLPs) from clarified Escherichia coli feedstock. The modified anion exchange media, core-shell adsorbents (InertShell and InertLayer 1000) and polymer grafted adsorbents (SQ) were compared. The results of chromatography from packed bed column of core-shell adsorbents showed that there is a trade-off between the purity and recovery of HB-VLPs in the flowthrough fraction due to the shell thickness. Atomic force microscopic analysis revealed funnel-shaped pore channels in the shell layer which may contribute to the entrapment of HB-VLPs. A longer residence time at a lower feed flow rate (0.5ml/min) improved slightly the HB-VLPs purity in all modified adsorbents, but the recovery in InertShell reduced substantially. The preheat-treatment is not recommended for the negative chromatography as the thermal-induced co-aggregation of HCPs and HB-VLPs would flow along with HB-VLPs and thus reduced the HB-VLPs purity in the flowthrough. Further reduction in the feedstock concentration enhanced the purity of HB-VLPs especially in InertLayer 1000 but reduced substantially the recovery of HB-VLPs. In general, the polymer grafted adsorbent, SQ, performed better than the core-shell adsorbents in handling a higher feedstock concentration. PMID:27059397

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

    International Nuclear Information System (INIS)

    Desorption characteristics of C-14 adsorbed on spent resin as H14CO3 ion type by applying various stripping solutions were analyzed, and some experiments for gasification of C-14 to CO2 gas with were also performed. Based on these results, the process concept for spent resin treatment was suggested. Real spent resin was prepared from sampling in storage tank in site 1 of Wolseung Nuclear Power Plant. Desorption characteristics of C-14 and cations of Cs, Co from spent IRN-150 resin was evaluated. Desorption efficiency of C-14 from spent resin by using H3PO4 desorption solution was over 96% regardless of C-14 amount on initial spent resin when comparing a activity of C-14 on initial spent resin. Also, desorption percent of cation of Cs, Co from anion ion-exchange resin (IRN-77) showed that Co-60 was below 1%, Cs-134, 137 was in a range of 2 ∼ 5%. Fundamental studies include an development of adsorbent manufacturing technology and its performance evaluation for C-14 gas trapping, the adsorption process by adopting gas circulation method was suggested for the design of 14CO2 gas treatment system generated from spent resin treatment process. In order to predict adsorbent performance of CO2 trapping, modelling was carried out to verify the breakthrough curves of CO2 trapping by using soda lime adsorbent. The effect of humidity on CO2 trapping by using soda lime adsorbent was modelled via chemical reaction in porous media. Assessment of the state-of-the-arts on the solidification of the used adsorbent showed that the cement matrix would be the best-available binder from the view points of the matrix compatibility, properties of the final waste form, simplicity of the process and relatively low cost

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2014-08-01

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

  11. Interaction between adsorbed hydrogen and potassium on a carbon nanocone containing material as studied by photoemission

    Energy Technology Data Exchange (ETDEWEB)

    Yu, Xiaofeng [Nesna University College, 8700 Nesna (Norway); Raaen, Steinar, E-mail: sraaen@ntnu.no [Physics Department, Norwegian University of Science and Technology, 7491 Trondheim (Norway)

    2015-09-14

    Hydrogen adsorption on a potassium doped carbon nanocone containing material was studied by photoelectron spectroscopy and work function measurement. The valence band spectra indicate that there is charge transfer from potassium to carbon. Upon deposition on carbon potassium is in its ionic state for lower doping and shows both ionic and metallic behavior at higher doping. Adsorption of hydrogen facilitates diffusion of potassium on the carbon material as seen by changes in the K{sub 2p} core level spectrum. Variations in the measured sample work function indicate that hydrogen initially adsorb on the K dopants and subsequently adsorb on the carbon cone containing material.

  12. Molecular structure and Equilibrium forces of bovine submaxillary mucin adsorbed at a solid-liquid interface

    DEFF Research Database (Denmark)

    Zappone, Bruno; Patil, Navinkumar J.; Madsen, Jan Busk;

    2015-01-01

    By combining dynamic light scattering, circular dichroism spectroscopy, atomic force microscopy, and surface force apparatus, the conformation of bovine submaxillary mucin in dilute solution and nanomechanical properties of mucin layers adsorbed on mica have been investigated. The samples were......, yet of the same order of magnitude as the diameter, indicating that the molecule can be modeled as a relatively rigid polymeric chain due to the large persistence length of the central glycosylated domain. Mucin molecules adsorbed abundantly onto mica from saline buffer, generating polymer-like, long...

  13. Use of Low-cost Adsorbents to Chlorophenols and Organic Matter Removal of Petrochemical Wastewater

    Directory of Open Access Journals (Sweden)

    Aretha Moreira de Oliveira

    2013-11-01

    Full Text Available The removal of 2,4 diclorophenol (2,4-DCF and 2,4,6 trichlorophenol (2,4,6 TCF present in  petrochemical wastewater was evaluated using low-cost adsorbents, such as chitin, chitosan and coconut shells. Batch studies showed that the absorption efficiency for 2,4 DCF and 2,4,6 TCF follow the order: chitosan > chitin > coconut shells. Langmuir and Freundlich models have been applied to experimental isotherms data, to better understand the adsorption mechanisms. Petrochemical wastewater treatment with fixed bed column system using chitinous adsorbents showed a removal of COD (75% , TOG (90% and turbidity (74-89%.

  14. Characterization and Testing of Amidoxime-Based Adsorbent Materials to Extract Uranium from Natural Seawater

    Energy Technology Data Exchange (ETDEWEB)

    Kuo, Li-Jung; Janke, Christopher J.; Wood, Jordana R.; Strivens, Jonathan E.; Das, S.; Oyola, Y.; Mayes, R. T.; Gill, Gary A.

    2016-04-20

    Extraction of uranium (U) from seawater for use as a nuclear fuel is a significant challenge due to the low concentration of U in seawater (∼3.3 ppb) and difficulties to selectively extract U from the background of major and trace elements in seawater. The Pacific Northwest National Laboratory (PNNL)’s Marine Sciences Laboratory (MSL) has been serving as a marine test site for determining performance characteristics (adsorption capacity, adsorption kinetics, and selectivity) of novel amidoxime-based polymeric adsorbents developed at Oak Ridge National Laboratory (ORNL) under natural seawater exposure conditions. This manuscript describes the performance of three formulations (38H, AF1, AI8) of amidoxime-based polymeric adsorbents produced at ORNL in MSL’s ambient seawater testing facility. The adsorbents were produced in two forms, fibrous material (40−100 mg samples) and braided material (5−10 g samples), and exposed to natural seawater using flow-through columns and recirculating flumes. All three formulations demonstrated high 56 day uranium adsorption capacity (>3 g U/kg adsorbent). The AF1 formulation had the best uranium adsorption performance, with a 56 day capacity of 3.9 g U/ kg adsorbent, a saturation capacity of 5.4 g U/kg adsorbent, and ∼25 days half-saturation time. The two exposure methods, flowthrough columns and flumes, were demonstrated to produce similar performance results, providing confidence that the test methods were reliable, that scaling up from 10’s of mg quantities of exposure in flow-through columns to gram quantities in flumes produced similar results, and confirm that the manufacturing process produces a homogeneous adsorbent. Adsorption kinetics appear to be element specific, with half-saturation times ranging from minutes for the major cations in seawater, to 8−10 weeks for V and Fe. Reducing the exposure time provides a potential pathway to improve the adsorption capacity of U by reducing the V/U ratio on the

  15. Local field distribution and configuration of CO molecules adsorbed on the nanostructure platinum surface

    Institute of Scientific and Technical Information of China (English)

    Huang Xiao-Jing; He Su-Zhen; Wu Chen-Xu

    2006-01-01

    This paper shows that the local electric field distribution near the nanostructure metallic surface is obtained by solving the Laplace equation, and furthermore, the configuration of CO molecules adsorbed on a Pt nanoparticle surface is obtained by using Monte Carlo simulation. It is found that the uneven local electric field distribution induced by the nanostructure surface can influence the configuration of carbon monoxide (CO) molecules by a force, which drags the adsorbates to the poles of the nanoparticles. This result, together with our results obtained before, may explain the experimental results that the nanostructure metallic surface can lead to abnormal phenomena such as anti-absorption infrared effects.

  16. New method for the preparation of adsorbent with high adsorption capacity

    Institute of Scientific and Technical Information of China (English)

    WANG Yongjian; LIU Jianfeng; DUO Jia; YU Yaoting

    2005-01-01

    Polyamidoamine (PAMAM) is a type of macro- molecule having a definite chemical structure and a large number of terminal functional groups. The synthetic approach of the adsorbent with high adsorption capacity involved arching of PAMAM onto cellulose beads by reaction with epichlorohydrin. The product thus prepared had a large number of amino groups of 2.94 mmol/g derived from 0.23 mmol/g epoxy groups on cellulose beads. This method presents an effective method for the preparation of high-loading adsorbents.

  17. Determination of the coefficient of iodine absorption carbon materials adsorber ventilation NPP using stable isotopes

    International Nuclear Information System (INIS)

    Submitted by nuclear-physical methods of determining the coefficient of absorption of iodine carbon materials using stable isotopes of iodine. Designed and created by pumping and measuring iodine content units. The processes of dynamic sorption of iodine on industrial carbon adsorbents studied the possibility of determining the iodine content of nuclear-physical methods and presents the metrological characteristics x-ray method. Application methods allow for the certification of carbon adsorbents gas cleaning systems and improve the safety of nuclear power plant operation

  18. Mechanism and Removal Efficiency of C.I. Acid Blake 1 by Pumice Stone Adsorbent

    OpenAIRE

    Norouzi, M; M. Zarrabi; M Noori Sepehr; M.R Samarghandi; F Amraie

    2011-01-01

    "n "n "nBackgrounds and Objectives: Treatment of colored wastewater is one of the important challenges of environmental engineers. Adsorption process is a key option for removal of organic matter from wastewater. The aim of present work was to investigate pumice stone as an adsorbent for removal of Acid Black 1 from aqueous solution."nMaterials and Methods: Removal of Acid Black 1 by pumice stone was investigated. Acid Hyrdo Chloric(HCL) 1 N was used to increse adsorbent porosity. Various par...

  19. A reexamination of the effects of adsorbates on the Raman spectrum of gibbsite.

    Science.gov (United States)

    Cunningham, K.W.; Goldberg, M.C.

    1983-01-01

    Previous workers have attributed substantial changes in the Raman intensities of the OH stretching bands in solid, powdered gibbsite of surface area 10 m2/g to surface interactions with the adsorbates 093Ca2+,HxPO43x- and SiO2.xH2O. These changes apparently resulted from an unsatisfactory Raman measurement procedure as a re-examination using an internal intensity standard (Na2C2O4 crystals) with gibbsite of surface area 39 m2/g showed no significant changes in the low-frequency band-height ratios of gibbsite and adsorbates.-D.J.M.

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

    International Nuclear Information System (INIS)

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

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

    OpenAIRE

    Sadadinovic, J.; Mičević, S.

    2008-01-01

    Investigation of the gas fraction in coal beds in Bosnia & Herzegovina has been performed systematically since 1988. Gas in coal beds can be present in free or adsorbed form, and dissolved in water. Methods of investigation are based on the direct approach, according to which the gas fraction is determined in the undisturbed coal bed.The quantity of the adsorbed and free gas in the coal bed is directly proportional to the gas pressure. Dependence is hyperbolic. The quantity of the free gas in...

  2. On stabilization of free radicals under γ-irradiation of molecules adsorbed by zeolites

    International Nuclear Information System (INIS)

    Investigated are ESR spectra and stability of free radicals forming as a result of γ-irradiation at -196 deg of triethylbenzol, diethyl spirit of dimethylmalon acid and tret butylbenzol, sorbed by NaX and CaX zeolites at room and increased temperatures. Anomalously high stability is characteristic only of radicals formed of γ-irradiated molecules, traversing close to the diameter of zeolite entry windows. The obtained data testifies to the effect that radiospectroscopy in combination with radiation effect on the adsorbed substances can successfully be used as the most sensitive method for porous structure characteristic of mineral adsorbents, in particular, for direct investigation of activized physical adsorption processes

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

    CERN Document Server

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

    2002-01-01

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

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

    Institute of Scientific and Technical Information of China (English)

    Li Yuan; Wang Xiang; Gao Wei; Cai Shaoxi

    2004-01-01

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

  5. Charge-transfer photodissociation of adsorbed molecules via electron image states

    CERN Document Server

    Jensen, E T

    2007-01-01

    The 248nm and 193nm photodissociation of submonolayer quantities of CH$_3$Br and CH$_3$I adsorbed on thin layers of n-hexane indicate that the dissociation is caused by dissociative electron attachment from sub-vacuum level photoelectrons created in the copper substrate. The characteristics of this photodissociation-- translation energy distributions and coverage dependences show that the dissociation is mediated by an image potential state which temporarily traps the photoelectrons near the n-hexane--vacuum interface, and then the charge transfers from this image state to the affinity level of a co-adsorbed halomethane which then dissociates.

  6. Superparamagnetic adsorbents for high-gradient magnetic fishing of lectins out of legume extracts

    DEFF Research Database (Denmark)

    Heebøll-Nielsen, Anders; Dalkiær, M.; Hubbuch, Jürgen;

    2004-01-01

    This work presents the development, testing, and application in high-gradient magnetic fishing of superparamagnetic supports for adsorption of lectins. Various approaches were examined to produce affinity, mixed mode, and hydrophobic charge induction type adsorbents. In clean monocomponent systems......-linked adsorbents supplied sufficient competition to dissolved sugars to selectively bind concanavalin A in an extract of jack beans. The dextran-linked supports were employed in a high-gradient magnetic fishing experiment, in which concanavalin A was purified to near homogeneity from a crude, unclarified extract...

  7. In situ modification of chromatography adsorbents using cold atmospheric pressure plasmas

    Science.gov (United States)

    Olszewski, P.; Willett, T. C.; Theodosiou, E.; Thomas, O. R. T.; Walsh, J. L.

    2013-05-01

    Efficient manufacturing of increasingly sophisticated biopharmaceuticals requires the development of new breeds of chromatographic materials featuring two or more layers, with each layer affording different functions. This letter reports the in situ modification of a commercial beaded anion exchange adsorbent using atmospheric pressure plasma generated within gas bubbles. The results show that exposure to He-O2 plasma in this way yields significant reductions in the surface binding of plasmid DNA to the adsorbent exterior, with minimal loss of core protein binding capacity; thus, a bi-layered chromatography material exhibiting both size excluding and anion exchange functionalities within the same bead is produced.

  8. The biogeochemical cycle of the adsorbed template. I - formation of the template

    Science.gov (United States)

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

    1987-01-01

    Experimental results are presented for the verification of the first adsorption step of the 'adsorbed template' biogeochemical cycle, a simple model for a primitive prebiotic replication system. The adsorption of Poly-C, Poly-U, Poly-A, Poly-G, and 5'-AMP, 5'-GMP, 5'-CMP and 5'-UMP onto gypsum was studied. It was found that under the conditions of the experiment, the polymers have a very high affinity for the mineral surface, while the monomers adsorb much less efficiently.

  9. An in-situ RBS system for measuring nuclides adsorbed at the liquid-solid interface

    Energy Technology Data Exchange (ETDEWEB)

    Morita, K.; Yuhara, J.; Ishigami, R. [Nagoya Univ. (Japan). School of Engineering] [and others

    1997-03-01

    An in-situ RBS system has been developed in which heavier nuclides adsorbed at the inner surface of a thin lighter window specimen of liquid container in order to determine the rate constants for their sorption and release at the interface. The testing of a thin silicon window of the sample assembly, in which Xe gas of one atmosphere was enclosed, against the bombardment of the probing ion beam has been performed. A desorption behavior of a lead layer adsorbed at the SiO{sub 2} layer of silicon window surface into deionized water has been measured as a preliminary experiment. (author)

  10. Controlled uniform coating from the interplay of Marangoni flows and surface-adsorbed macromolecules

    CERN Document Server

    Kim, Hyoungsoo; Um, Eujin; Jacobi, Ian; Button, Ernie; Stone, Howard A

    2016-01-01

    Surface coatings and patterning technologies are essential for various physicochemical applications. In this Letter, we describe key parameters to achieve uniform particle coatings in binary solutions: First, multiple sequential Marangoni flows, set by solute and surfactant simultaneously, prevent non-uniform particle distributions and continuously mix suspended materials during droplet evaporation. Second, we show the importance of particle-surface interactions that can be established by surface-adsorbed macromolecules. To achieve a uniform deposit in a binary mixture a small concentration of surfactant and surface-adsorbed polymer (0.05 wt% each) is sufficient, which offers a new physicochemical avenue for control of coatings.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2015-02-01

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

  12. Interlocking order parameter fluctuations in structural transitions between adsorbed polymer phases.

    Science.gov (United States)

    Martins, Paulo H L; Bachmann, Michael

    2016-01-21

    By means of contact-density chain-growth simulations of a simple coarse-grained lattice model for a polymer grafted at a solid homogeneous substrate, we investigate the complementary behavior of the numbers of surface-monomer and monomer-monomer contacts under various solvent and thermal conditions. This pair of contact numbers represents an appropriate set of order parameters that enables the distinct discrimination of significantly different compact phases of polymer adsorption. Depending on the transition scenario, these order parameters can interlock in perfect cooperation. The analysis helps understand the transitions from compact filmlike adsorbed polymer conformations into layered morphologies and dissolved adsorbed structures, respectively, in more detail.

  13. Molecular adsorbates under high pressure: a study using surface-enhanced Raman scattering spectroscopy

    International Nuclear Information System (INIS)

    Molecules adsorbed on metal surfaces were studied in a diamond anvil cell with Ar pressure-transmission medium up to several GPa pressure using Raman spectroscopy. The problem with studying molecules on surfaces is the small number density. This problem was overcome using photonic substrates to amplify the Raman intensity by factors of 106 in the case of self-assembled monolayers on Ag-coated nanoarrays, where the probed region contained ∼109 molecules, and >109 in the case of the dye Rhodamine 6G on Ag nanoaggregates, where <106 molecules were probed. Pressure effects on the adsorbate vibrations and on the underlying nanostructures are discussed.

  14. Nanoclay-Based Solid-Amine Adsorbents for Carbon Dioxide Capture

    Science.gov (United States)

    Roth, Elliot A.

    The objective of this research was to develop an efficient, low cost, recyclable solid sorbent for carbon dioxide adsorption from large point sources, such as coal-fired power plants. The current commercial way to adsorb CO 2 is to use a liquid amine or ammonia process. These processes are used in industry in the "sweetening" of natural gas, but liquid based technologies are not economically viable in the adsorption of CO2 from power plants due to the extremely large volume of CO2 and the inherent high regeneration costs of cycling the sorbent. Therefore, one of the main objectives of this research was to develop a novel sorbent that can be cycled and uses very little energy for regeneration. The sorbent developed here is composed of a nanoclay (montmorillonite), commonly used in the production of polymer nanocomposites, grafted with commercially available amines. (3-aminopropyl) trimethoxysilane (APTMS) was chemically grafted to the edge hydroxyl groups of the clay. While another amine, polyethylenimine (PEI), was attached to the surface of the clay by electrostatic interactions. To confirm the attachment of amines to the clay, the samples were characterized using FTIR and the corresponding peaks for amines were observed. The amount of amine loaded onto the support was determined by TGA techniques. The treated clay was initially analyzed for CO2 adsorption in a pure CO 2 stream. The adsorption temperatures that had the highest adsorption capacity were determined to be between 75°C and 100°C for all of the samples tested at atmospheric pressure. The maximum CO2 adsorption capacity observed was with nanoclay treated with both APTMS and PEI at 85°C. In a more realistic flue gas of 10% CO2 and 90% N2, the adsorbents had essentially the same overall CO2 adsorption capacity indicating that the presence of nitrogen did not hinder the adsorption of CO2. Adsorption studies in pure CO2 at room temperature under pressure from 40-300 PSI were also conducted. The average

  15. 扩张床吸附剂:制备及功能化%Adsorbents for Expanded Bed Adsorption: Preparation and Functionalization

    Institute of Scientific and Technical Information of China (English)

    赵珺; 姚善泾; 林东强

    2009-01-01

    Expanded bed adsorption (EBA), a promising and practical separation technique, has been widely stud-ied in the past two decades. The development of adsorbents for EBA process is a challenging course, with the spe-cial design and preparation according to the target molecules and specific expanded bed systems. Many types of supporting matrices for expanded bed adsorbents have been developed, and their preparation methods are being consummated gradually. These matrices are activated and then coupled with ligands to form functionalized adsorb-ents, including ion-exchange adsorbents, affinity adsorbents, mixed mode adsorbents, hydrophobic charge induction chromatography adsorbents and others. In this review, the preparation of the matrices for EBA process is summa-rized, and the coupling of ligands to the matrices to prepare functionalized adsorbents is discussed as well.

  16. OZONE REACTION WITH N-ALDEHYDES (N=4-10), BENZALDEHYDE, ETHANOL, ISOPROPANOL, AND N-PROPANOL ADSORBED ON A DUAL-BED GRAPHITIZED CARBON/CARBON MOLECULAR SIEVE ADSORBENT CARTRIDGE

    Science.gov (United States)

    Ozone reacts with n-aldehydes (n = 4 - 10), benzaldehyde, ethanol, isopropanol, and n-propanol adsorbed on a dual-bed graphitized carbon/carbon molecular sieve adsorbent cartridge. Destruction of n-aldehydes increases with n number and with ozone concentration. In some samp...

  17. A DRIFTS STUDY OF THE MORPHOLOGY AND SURFACE ADSORBATE COMPOSITION OF AN OPERATING METHANOL SYNTHESIS CATALYST

    NARCIS (Netherlands)

    BAILEY, S; FROMENT, GF; SNOECK, JW; WAUGH, KC

    1995-01-01

    The nature of the species adsorbed on a Cu/ZnO/Al2O3 catalyst while it was producing methanol has been elucidated in this study using DRIFTS. The species are carbonates, formate, CO, oxygen atoms (similar to 2% of a monolayer) and methoxy on the Cu and methoxy on the ZnO. The frequencies observed fo

  18. Neutron Scattering Study of Nitrogen Adsorbed on Basal Plane Oriented Graphite

    DEFF Research Database (Denmark)

    Kjems, Jørgen; Passell, L.; Taub, H.;

    1976-01-01

    Thermal-neutron scattering has been used to investigate the structure of nitrogen films adsorbed on Grafoil, a basal-plane-oriented graphite. Diffraction scans were made at coverages between 1/3 of a monolayer and 7/4 monolayers over a temperature range from 10 to 90 K. The observed line shapes...

  19. Linear hydrogen adsorbate structures on graphite induced by self-assembled molecular monolayers

    DEFF Research Database (Denmark)

    Nilsson, Louis; Sljivancanin, Zeljko; Balog, Richard;

    2012-01-01

    Combined scanning tunnelling microscopy measurements and density functional theory calculations reveal a method to induce linear structures of hydrogen adsorbates on graphite by covering the surface with a self-assembled molecular monolayer of cyanuric acid and exposing it to atomic hydrogen...

  20. Study on development of adsorbent of acetaldehyde; Acetaldehyde yo kyuchakuzai no kaihatsu ni kansuru kenkyu

    Energy Technology Data Exchange (ETDEWEB)

    Noda, T. [Nippon Steel Corp., Tokyo (Japan); Suzuki, M. [The University of Tokyo, Tokyo (Japan). Institute of Industrial Science

    1997-07-10

    The adsorption of acetaldehyde by porous ceramics impregnated with hydrazinium aluminum sulfate (HAS) is studied. Silicagel, activated alumina, activated clay, and activated carbon are compared, and it is found that silicagel and activated clay are suitable as a substrate for HAS impregnated adsorbent. The adsorption mechanism of acetaldehyde by the adsorbent is believed to be one in which acetaldehyde reacts with hydrazinium and yields acetaldazine. The adsorption capacity of the adsorbent at low acetaldehyde concentration of 0.1 ppm was as large as 1.36 mol/kg. This adsorption capacity at 0.1 ppm acetaldehyde concentration is remarkably larger than that of conventional activated carbon. Hydrazinium decomposes easily in the air because it is a strong reducing agent and reacts with oxygen or carbon dioxide. But hydrazinium impregnated on porous ceramics with HAS becomes more stable and maintains reactivity with acetaldehyde for longer than six months. An adsorbent made of porous ceramics impregnated with HAS is useful as a deodorant for acetaldehyde. 8 refs., 6 figs., 6 tabs.

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

    Energy Technology Data Exchange (ETDEWEB)

    Kenny, T.W.

    1989-05-01

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

  2. Single walled carbon nanotubes with functionally adsorbed biopolymers for use as chemical sensors

    Science.gov (United States)

    Johnson, Jr., Alan T

    2013-12-17

    Chemical field effect sensors comprising nanotube field effect devices having biopolymers such as single stranded DNA or RNA functionally adsorbed to the nanotubes are provided. Also included are arrays comprising the sensors and methods of using the devices to detect volatile compounds.

  3. Evaluation of commercial chromatographic adsorbents for the direct capture of polyclonal rabbit antibodies from clarified antiserum

    DEFF Research Database (Denmark)

    Bak, Hanne; Thomas, O.R.T.

    2007-01-01

    We have carried out a rigorous evaluation of eight commercially available packed bed chromatography adsorbents for direct capture and purification of immumoglobulins from clarified rabbit antiserum. Three of these materials featured rProtein A (rProtein A Sepharose Fast Flow, Mabselect, Prosep r...

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2015-08-15

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

  5. REMOVAL OF REACTIVE DYES FROM WASTEWATER OF TEXTILE INDUSTRIES BY USING ENVIRONMENTAL FRIENDLY ADSORBENTS

    Directory of Open Access Journals (Sweden)

    ALAM Md Shamim

    2016-05-01

    Full Text Available This paper is aimed at developing a method to treat wastewater by using inexpensive adsorbents. Textile industries produce wastewater, otherwise known as effluent, as a bi-product of their production. The effluent contains several pollutants. Among the various stages of textile production, the operations in the dyeing plant, which include pre-treatments, dyeing, printing and finishing, produce the most pollution. The textile dyeing wastes contain unused or partially used organic compounds, and high level of different pollutants. They are often of strong color and may also be of high temperature. When disposed into water bodies or onto land these effluents will result in the deterioration of ecology and damage to aquatic life. Furthermore they may cause damage to fisheries and economic loss to fishermen and farmer, there may be impacts on human health which can be removed with the help of an effluent treatment plant (ETP. The “clean” water can then be safely discharged into the environment and ultimately save our environment from pollution. In this study, rice husk and cotton dust were used as an adsorbent. In this research work waste water was characterized with this useless adsorbents. The parameters which were tested in this study are DO, BOD, COD, TS, TDS and TSS. The results showed that the selected bio adsorbents have good potential for removal of reactive dyes from textile effluent.

  6. The chemistry of copper-containing sulfur adsorbents in the presence of mercaptans

    Energy Technology Data Exchange (ETDEWEB)

    Turbeville, Wayne; Yap, Nora [Sued-Chemie Inc., 1600 W. Hill St., Louisville, KY 40210 (United States)

    2006-09-15

    A brief review of the chemistry of copper and thiols is given and a contrast is made to the behavior of copper-containing adsorbents used for the desulfurization of liquid hydrocarbon streams that are routinely treated in refinery processes. A study was made of the chemistry between copper adsorbents and model liquid feed streams containing mercaptans. It was found that sulfur capacity can be quite high, greater than 8% by weight, and is dependent on the dispersion of the copper oxide on the adsorbent. In addition, it is shown that bulk copper is involved in the adsorption of mercaptans, as there is significantly more sulfur than there is copper on the surface. At a temperature of approximately 150{sup o}C, very well formed lamellar crystals of copper(I) thiolate are formed, which indicates that the copper migrates from the surface of the catalyst to expose bulk copper for further reaction. When the temperature is raised to 190{sup o}C, there is evidence that the copper(I) butanethiolate decomposes to copper(I) sulfide. Reaction mechanisms are proposed for the process of desulfurization of liquid hydrocarbon streams containing mercaptans when using a copper-containing adsorbent. (author)

  7. Regeneration and efficiency characterization of hybrid adsorbent for thermal energy storage of excess and solar heat

    Energy Technology Data Exchange (ETDEWEB)

    Dicaire, Daniel; Tezel, F. Handan [University of Ottawa, Department of Chemical and Biological Engineering, 161 Louis Pasteur, Colonel By Hall, A402, Ottawa, ON, K1N 6N5 (Canada)

    2011-03-15

    Adsorption Thermal Energy Storage (TES) is a promising technology for long term thermal energy storage of excess and solar heat. By using the exothermic reversible adsorption process, excess heat from an incinerator or solar heat from the summer can be stored and then released for heating during the winter. The usefulness of the storage system relies heavily on the temperature and quality of the heat available for regeneration of the adsorbent as it affects the storage efficiency, the amount of water released from the adsorbent and in turn the performance or energy density of the storage system. In this study, a lab scale high throughput open loop forced air adsorption TES has been built. A series of adsorption experiments were performed to determine the effect of adsorption flow rate and cycling on the chosen best performing adsorbent, AA13X from Rio Tinto Alcan. Regeneration characterization experiments were performed to determine the effect of flow rate, temperature and feed air relative humidity on the regeneration and performance of the system. The results were compared with another adsorbent to verify the observed trend. Finally, the efficiency of the thermal storage system was calculated. (author)

  8. Study complex of properties of the adsorbent for renewal filters of ventilation systems NPP

    International Nuclear Information System (INIS)

    Using standard and developed at NSC KIPT techniques it was carried out a comprehensive research of working characteristics (aerodynamic resistance in conditions modeling work adsorber AU-1500; mechanical strength abrasion; adsorption capacity for iodine and methyl iodide) of activated coals from different manufacturers, intended for use in rehabilitation and reconstruction of the adsorption filter ventilation system at NPP

  9. Selection of adsorbents for in-situ coupling technology of adsorptive desulfurization and biodesulfurization

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    In-situ coupling of adsorptive desulfurization and biodesulfurization is a new desulfurization technol- ogy for fossil oil. It has the merits of high-selectivity of biodesulfurization and high-rate of adsorptive desulfurization. It is carried out by assembling nano-adsorbents onto surfaces of microbial cells. In this work, In-situ coupling desulfurization technology of widely used desulfurization adsorbents of γ-Al2O3, Na-Y molecular sieves, and active carbon with Pseudomonas delafieldii R-8 were studied. Results show that Na-Y molecular sieves restrain the activity of R-8 cells and active carbon cannot desorb the sub- strate dibenzothiophene (DBT). Thus, they are not applicable to in-situ coupling desulfurization tech- nology. Gamma-Al2O3 can adsorb DBT from oil phase quickly, and then desorb it and transfer it to R-8 cells for biodegradation, thus increasing desulfurization rate. It is also found that nano-sized γ-Al2O3 increases desulfurization rate more than regular-sized γ-Al2O3. Therefore, nano- γ-Al2O3 is regarded as the better adsorbent for this in-situ coupling desulfurization technology.

  10. A Modified Chitosan Adsorbent for Selective Removal of Low Density Lipoprotein

    Institute of Scientific and Technical Information of China (English)

    Guo Qi FU; Ke Yu SHI; Zhi YUAN; Wen Qiang NIU; Bing Lin HE; Bin LIU; Bin SHEN; Yan LIU

    2004-01-01

    A modified chitosan adsorbent was synthesized through a simple preparation procedure, and it demonstrated good adsorption performance for selective removal of low density lipoprotein in human plasma. Phase inversion technique was employed to form chitosan beads, to which epoxy groups were then introduced by reacting with ethyleneglycol diglycidylether, and tryptophan was subsequently coupled to the epoxy-activated beads.

  11. [Characteristics and comparative study of a new drinking-water defluoridation adsorbent Bio-F].

    Science.gov (United States)

    Zhu, Chi; Zhao, Liang-Yuan; Yuan, Heng; Yang, Han-Ying; Li, Ang; Wang, Peng; Yang, Shao

    2009-04-15

    To evaluate the application potentiality pf a new type drinking-water defluoridation adsorbent Bio-F, comparative study on the defluoridation characteristics of common adsorbents activated alumina (AA), bone char (BC), activated clinoptilolite (AC) with Bio-F was conducted. The defluoridation characteristics under different conditions, such as particle diameter, pH, retention time, fluorine concentration, regeneration stability, were investigated by continuous-flow column experiments and static tests. The defluoridation efficiency of high fluoride underground water by four types of adsorbents was also compared. The results showed that F(-) adsorption kinetics of Bio-F fitted the Lagergren First-order equation (R2 = 0.9580). F(-) adsorption by Bio-F was found to fit the Langmuir adsorption isotherm (R2 = 0.9992). The results indicated that the static defluoridation capacity (DC) of Bio-F was 4.0883 mg x g(-1), which was about 1.8 folds and 5.8 folds of those of AA and AC respectively. DC of all four adsorbents was positively correlated with F(-) concentration and negatively correlated with particle size. High concentration of CO3(2-) and HCO3(-) reduced the DC of Bio-F (p water defluoridation.

  12. Structural and sorption characteristics of adsorbed humic acid on clay minerals.

    Science.gov (United States)

    Wang, Kaijun; Xing, Baoshan

    2005-01-01

    Clay-humic complexes are commonly distributed in natural environments. They play very important roles in regulating the transport and retention of hydrophobic organic contaminants in soils and sediments. This study examined the structural changes of humic acid (HA) after adsorption by clay minerals and determined phenanthrene sorption by clay-humic complexes. Solid- and liquid-state 13C nuclear magnetic resonance (NMR), for the first time, provided direct evidence for HA fractionation during adsorption on mineral surfaces, that is, aliphatic fractions were preferentially adsorbed by clay minerals while aromatic fractions were left in the solution. The ratio of UV absorbance of HA at 465 and 665 nm (E4 to E6 ratio), which is related to aromaticity, corroborated with the NMR results. For both montmorillonite and kaolinite, adsorbed HA fractions had higher sorption linearity (N) and affinity (K(oc)) than the source HA. The K(oc) of adsorbed HA for the clay-humic complexes could be up to several times higher than that of the source HA. This large increase may be contributed by the low polarity of the bound HA. Moreover, for each mineral, the N values of adsorbed HA increased with increasing HA loading. It is believed that HA may develop a more condensed structure on mineral surface at lower HA loading level due to the stronger interactions between HA and mineral surface as a result of close contacts. PMID:15647564

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

    International Nuclear Information System (INIS)

    Investigations of the properties of absorbed monolayers have received great experimental and theoretical attention recently, both because of the importance of surface processes in practical applications such as catalysis, and the importance of such systems to the understanding of the fundamentals of thermodynamics in two dimensions. We have adapted the composite bolometer technology to the construction of microcalorimeters. For these calorimeters, the adsorption substrate is an evaporated film deposited on one surface of an optically polished sapphire wafer. This approach has allowed us to make the first measurements of the heat capacity of submonolayer films of 4He adsorbed on metallic films. In contrast to measurements of 4He adsorbed on all other insulating substrates, we have shown that 4He on silver films occupies a two-dimensional gas phase over a broad range of coverages and temperatures. Our apparatus has been used to study the heat capacity of Indium flakes. CO multilayers, 4He adsorbed on sapphire and on Ag films and H2 adsorbed on Ag films. The results are compared with appropriate theories. 68 refs., 19 figs

  14. Application of chemically modified beach sand as low cost efficient adsorbent for dye removal

    Directory of Open Access Journals (Sweden)

    Reza Ansari

    2013-10-01

    Full Text Available In the current work, beach sand (BS and beach sand coated with polyaniline (BS/Pani were used as an efficient green adsorbent for dye removal from aqueous solutions. Methylene blue (MB was chosen as a test probe for the evaluation of the selected adsorbents for dye removal efficiency. The adsorption experiments were carried out in batch system and the effect of some important empirical parameters affecting adsorption processes were then investigated. The experimental data were also analyzed by Langmuir and Freundlich adsorption models. Based on the correlation coefficient values obtained (R2, it was found that equilibrium data for both adsorbents fitted well with both models. Adsorption data were also examined by pseudo-first-order and pseudo-second-order models and their respective rate constants were estimated. It was found that sorption of MB dye onto BS/Pani is fitted very well with pseudo-second-order kinetic model. Using the equilibrium concentration constants obtained at different temperatures, important thermodynamic parameters of the sorption process were calculated. It was found that the chemically modified beach sand is an effective and low cost adsorbent for dye removal from aqueous solutions.

  15. Local electric field and configuration of CO molecules adsorbed on a nanostructured surface with nanocones

    Institute of Scientific and Technical Information of China (English)

    You Rong-Yi; Huang Xiao-Jing

    2009-01-01

    Based on the nanostructured surface model that the (platinum,Pt) nanocones grow out symmetrically from a plane substrate,the local electric field near the conical nanoparticle surface is computed and discussed. On the basis of these results,the adsorbed CO molecules are modelled as dipoles,and three kinds of interactions,I.e. Interactions between dipoles and local electric field,between dipoles and dipoles,as well as between dipoles and nanostructured substrate,are taken into account. The spatial configuration of CO molecules adsorbed on the nanocone surface is then given by Monte-Carlo simulation. Our results show that the CO molecules adsorbed on the nanocone surface cause local agglomeration under the action of an external electric field,and this agglomeration becomes more compact with decreasing conical angle,which results in a stronger interaction among molecules. These results serve as a basis for explaining abnormal phenomena such as the abnormal infrared effect (AIRE),which was found when CO molecules were adsorbed on the nancetructured transition-metal surface.

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

    Science.gov (United States)

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

    2016-06-01

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

  17. Surface-enhanced Raman Scattering from Molecules Adsorbed on Mixed Silver/Gold Nanoparticle Surfaces

    Institute of Scientific and Technical Information of China (English)

    FANG Jing-huai; HUANG Yun-xia; LI Xia; DOU Xiao-ming

    2004-01-01

    @@ Introduction Since the first discovery of Surface-Enhanced Raman Scattering(SERS) from pyridine molecules adsorbed at roughened silver electrodes in 1974 by Fleischmann et al.[1],the research of SERS has made tremendous progress in applications of it to various fields of science and technology[2-8].

  18. Characterization of commercial ceramic adsorbents and its application on naphthenic acids removal of petroleum distillates

    Directory of Open Access Journals (Sweden)

    Juliana Pereira Silva

    2007-06-01

    Full Text Available The mixture of carboxylic acids present in petroleum oil and directly responsible for its acidity and corrosiveness in liquid phase during the refine process is denominated "naphthenic acids". These acids are also present in distilled fraction of petroleum, causing several problems in final products quality. A possible way to remove the carboxilic acids from petroleum distilled fractions is the adsorption in porous materials. However, the results obtained until now indicate that ion exchange resins would be the best adsorbents for this process, which would probably increase its cost. In this work, two commercial adsorbents (clay and activated alumina were characterized by a set of physical-chemistry techniques and evaluated concerning their capacity of removing naphthenic acids from a light petroleum fraction. It was verified the influence of a thermal treatment previous to the adsorption in its physical-chemistry characteristics and its properties. A high reduction of the TAN values was verified in the residual oils from both adsorbent, although there was a competition among all the compounds present in the light oil fraction for the adsorption sites, which can be probably related to the thermal pre-treatment. These results were related to corrosion yield experiments, and it was observed that the adsorbent pretreatment also affected the reduction in corrosion yields for both alumina and clay.

  19. Low cost adsorbents for the removal of organic pollutants from wastewater.

    Science.gov (United States)

    Ali, Imran; Asim, Mohd; Khan, Tabrez A

    2012-12-30

    Water pollution due to organic contaminants is a serious issue because of acute toxicities and carcinogenic nature of the pollutants. Among various water treatment methods, adsorption is supposed as the best one due to its inexpensiveness, universal nature and ease of operation. Many waste materials used include fruit wastes, coconut shell, scrap tyres, bark and other tannin-rich materials, sawdust and other wood type materials, rice husk, petroleum wastes, fertilizer wastes, fly ash, sugar industry wastes blast furnace slag, chitosan and seafood processing wastes, seaweed and algae, peat moss, clays, red mud, zeolites, sediment and soil, ore minerals etc. These adsorbents have been found to remove various organic pollutants ranging from 80 to 99.9%. The present article describes the conversion of waste products into effective adsorbents and their application for water treatment. The possible mechanism of adsorption on these adsorbents has also been included in this article. Besides, attempts have been made to discuss the future perspectives of low cost adsorbents in water treatment. PMID:23023039

  20. Comparative study on adsorption of perfluorooctane sulfonate (PFOS) and perfluorooctanoate (PFOA) by different adsorbents in water.

    Science.gov (United States)

    Yao, Yuan; Volchek, Konstantin; Brown, Carl E; Robinson, Adam; Obal, Terry

    2014-01-01

    Perfluorinated compounds (PFCs) are emerging environmental pollutants. Perfluorooctane sulfonate (PFOS) and perfluorooctanoate (PFOA) are the two primary PFC contaminants that are widely found in water, particularly in groundwater. This study compared the adsorption behaviors of PFOS and PFOA on several commercially available adsorbents in water. The tested adsorbents include granular activated carbon (GAC: Filtrasorb 400), powdered activated carbon, multi-walled carbon nanotube (MCN), double-walled carbon nanotube, anion-exchange resin (AER: IRA67), non-ion-exchange polymer, alumina, and silica. The study demonstrated that adsorption is an effective technique for the removal of PFOS/PFOA from aqueous solutions. The kinetic tests showed that the adsorption onto AER reaches equilibrium rapidly (2 h), while it takes approximately 4 and 24 h to reach equilibrium for MCN and GAC, respectively. In terms of adsorption capacity, AER and GAC were identified as the most effective adsorbents to remove PFOS/PFOA from water. Furthermore, MCN, AER, and GAC proved to have high PFOS/PFOA removal efficiencies (≥98%). AER (IRA67) and GAC (Filtrasorb 400) were thus identified as the most promising adsorbents for treating PFOS/PFOA-contaminated groundwater at mg L(-1) level based on their equilibrium times, adsorption capacities, removal efficiencies, and associated costs. PMID:25521134