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Sample records for adsorb large amounts

  1. Determination of maximal amount of minor gases adsorbed in a shale sample by headspace gas chromatography.

    PubMed

    Zhang, Chun-Yun; Hu, Hui-Chao; Chai, Xin-Sheng; Pan, Lei; Xiao, Xian-Ming

    2014-02-01

    In this paper, we present a novel method for determining the maximal amount of ethane, a minor gas species, adsorbed in a shale sample. The method is based on the time-dependent release of ethane from shale samples measured by headspace gas chromatography (HS-GC). The study includes a mathematical model for fitting the experimental data, calculating the maximal amount gas adsorbed, and predicting results at other temperatures. The method is a more efficient alternative to the isothermal adsorption method that is in widespread use today.

  2. DPPG Liposomes Adsorbed on Polymer Cushions: Effect of Roughness on Amount, Surface Composition and Topography.

    PubMed

    Duarte, Andreia A; Botelho do Rego, Ana M; Salerno, Marco; Ribeiro, Paulo A; El Bari, Nezha; Bouchikhi, Benachir; Raposo, Maria

    2015-07-01

    The adsorption of intact liposomes onto solid supports is a fundamental issue when preparing systems with encapsulated biological molecules. In this work, the adsorption kinetic of 1,2-dipalmitoyl-sn-glycero-3-[phospho-rac-(1-glycerol)] (sodium salt) liposomes onto cushions prepared from commom polyelectrolytes by the layer-by-layer technique was investigated with the main objective of finding the surface conditions leading to the adsorption of intact liposomes. For this purpose, different cushion surface roughnesses were obtained by changing the number of cushion bilayers. The adsorbed amount per unit area was measured through quartz crystal microbalance, surface morphology was characterized by atomic force microscopy, and the surface composition was assessed by X-ray photoelectron spectroscopy. The results show that (1) the amount of adsorbed lipids depends on the number of cushion bilayers, (2) the cushions are uniformly covered by the adsorbed lipids, and (3) the surface morphology of polymer cushions tunes liposome rupture and its adsorption kinetics. The fraction of ruptured liposomes, calculated from the measured amount of adsorbed lipids, is a function of surface roughness together with other surface morphology parameters, namely the dominating in-plane spatial feature size, the fractal dimension, and other textural features as well as amplitude and hybrid parameters. PMID:26076391

  3. Relationship between the amount of bitter substances adsorbed onto lipid/polymer membrane and the electric response of taste sensors.

    PubMed

    Toko, Kiyoshi; Hara, Daichi; Tahara, Yusuke; Yasuura, Masato; Ikezaki, Hidekazu

    2014-01-01

    The bitterness of bitter substances can be measured by the change in the membrane electric potential caused by adsorption (CPA) using a taste sensor (electronic tongue). In this study, we examined the relationship between the CPA value due to an acidic bitter substance and the amount of the bitter substance adsorbed onto lipid/polymer membranes, which contain different lipid contents, used in the taste sensor. We used iso-α-acid which is an acidic bitter substance found in several foods and beverages. The amount of adsorbed iso-α-acid, which was determined by spectroscopy, showed a maximum at the lipid concentration 0.1 wt % of the membrane, and the same phenomenon was observed for the CPA value. At the higher lipid concentration, however, the amount adsorbed decreased and then remained constant, while the CPA value decreased monotonically to zero. This constant adsorption amount was observed when the membrane potential in the reference solution did not change with increasing lipid concentration. The decrease in CPA value in spite of the constant adsorption amount is caused by a decrease in the sensitivity of the membrane as the surface charge density increases. The reason why the peaks appeared in both the CPA value and adsorption amount is based on the contradictory adsorption properties of iso-α-acid. The increasing charged lipid concentration of the membrane causes an increasing electrostatic attractive interaction between iso-α-acid and the membrane, but simultaneously causes a decreasing hydrophobic interaction that results in decreasing adsorption of iso-α-acid, which also has hydrophobic properties, onto the membrane. Estimates of the amount of adsorption suggest that iso-α-acid molecules are adsorbed onto both the surface and interior of the membrane. PMID:25184491

  4. Adsorption of enzymes to stimuli-responsive polymer brushes: Influence of brush conformation on adsorbed amount and biocatalytic activity.

    PubMed

    Koenig, Meike; Bittrich, Eva; König, Ulla; Rajeev, Bhadra Lakshmi; Müller, Martin; Eichhorn, Klaus-Jochen; Thomas, Sabu; Stamm, Manfred; Uhlmann, Petra

    2016-10-01

    Polyelectrolyte brushes can be utilized to immobilize enzymes on macroscopic surfaces. This report investigates the influence of the pH value of the surrounding medium on the amount and the activity of enzymes adsorbed to poly(2-vinylpyridine) and poly(acrylic acid) brushes, as well as the creation of thermoresponsive biocatalytically active coatings via the adsorption of enzymes onto a mixed brush consisting of a polyelectrolyte and temperature-sensitive poly(N-isopropylacryl amide). Spectroscopic ellipsometry and attenuated total reflection-Fourier transform infrared spectroscopy are used to monitor the adsorption process. Additionally, infrared spectra are evaluated in terms of the secondary structure of the enzymes. Glucose oxidase is used as a model enzyme, where the enzymatic activity is measured after different adsorption conditions. Poly(acrylic acid) brushes generally adsorb larger amounts of enzyme, while less glucose oxidase is found on poly(2-vinylpyridine), which however exhibits higher specific activity. This difference in activity could be attributed to a difference in secondary structure of the adsorbed enzyme. For glucose oxidase adsorbed to mixed brushes, switching of enzymatic activity between an active state at 20°C and a less active state at 40°C as compared to the free enzyme in solution is observed. However, this switching is strongly depending on pH in mixed brushes of poly(acrylic acid) and poly(N-isopropylacryl amide) due to interactions between the polymers.

  5. Adsorption of enzymes to stimuli-responsive polymer brushes: Influence of brush conformation on adsorbed amount and biocatalytic activity.

    PubMed

    Koenig, Meike; Bittrich, Eva; König, Ulla; Rajeev, Bhadra Lakshmi; Müller, Martin; Eichhorn, Klaus-Jochen; Thomas, Sabu; Stamm, Manfred; Uhlmann, Petra

    2016-10-01

    Polyelectrolyte brushes can be utilized to immobilize enzymes on macroscopic surfaces. This report investigates the influence of the pH value of the surrounding medium on the amount and the activity of enzymes adsorbed to poly(2-vinylpyridine) and poly(acrylic acid) brushes, as well as the creation of thermoresponsive biocatalytically active coatings via the adsorption of enzymes onto a mixed brush consisting of a polyelectrolyte and temperature-sensitive poly(N-isopropylacryl amide). Spectroscopic ellipsometry and attenuated total reflection-Fourier transform infrared spectroscopy are used to monitor the adsorption process. Additionally, infrared spectra are evaluated in terms of the secondary structure of the enzymes. Glucose oxidase is used as a model enzyme, where the enzymatic activity is measured after different adsorption conditions. Poly(acrylic acid) brushes generally adsorb larger amounts of enzyme, while less glucose oxidase is found on poly(2-vinylpyridine), which however exhibits higher specific activity. This difference in activity could be attributed to a difference in secondary structure of the adsorbed enzyme. For glucose oxidase adsorbed to mixed brushes, switching of enzymatic activity between an active state at 20°C and a less active state at 40°C as compared to the free enzyme in solution is observed. However, this switching is strongly depending on pH in mixed brushes of poly(acrylic acid) and poly(N-isopropylacryl amide) due to interactions between the polymers. PMID:27447452

  6. Generalized convulsions after consuming a large amount of gingko nuts.

    PubMed

    Miwa, H; Iijima, M; Tanaka, S; Mizuno, Y

    2001-02-01

    We report a 36-year-old woman, without any past or family histories of epilepsy, who presented frequent vomiting and generalized convulsions. About 4 h before the convulsion, she had consumed approximately 70-80 gingko nuts, seeds of Gingko biloba, in an attempt to improve her health. It is important to know that convulsion may be induced if a large amount of gingko nuts is consumed. The neurotoxicity of gingko nuts, particularly their convulsion-inducing effect, should be recognized.

  7. Study of the Relationship between Taste Sensor Response and the Amount of Epigallocatechin Gallate Adsorbed Onto a Lipid-Polymer Membrane

    PubMed Central

    Harada, Yuhei; Tahara, Yusuke; Toko, Kiyoshi

    2015-01-01

    A taste sensor using lipid-polymer membranes has been developed to evaluate the taste of foods, beverages and medicines. The response of the taste sensor, measured as a change in the membrane potential caused by adsorption (CPA), corresponds to the aftertaste felt by humans. The relationships between the CPA value and the amount of adsorbed taste substances, quinine and iso-α acid (bitterness), and tannic acid (astringency), have been studied so far. However, that of epigallocatechin gallate (EGCg) has not been clarified, although EGCg is abundantly present in green tea as one of its astringent substances. This study aimed at clarifying the response of the taste sensor to EGCg and its relationship with the amount of EGCg adsorbed onto lipid-polymer membranes. The lipid concentration dependence of the CPA value was similar to that of the amount of adsorbed EGCg, indicating a high correlation between the CPA value and the amount of adsorbed EGCg. The CPA value increased with increasing amount of adsorbed EGCg; however, the CPA value showed a tendency of leveling off when the amount of adsorbed EGCg further increased. PMID:25781512

  8. Study of the relationship between taste sensor response and the amount of epigallocatechin gallate adsorbed onto a lipid-polymer membrane.

    PubMed

    Harada, Yuhei; Tahara, Yusuke; Toko, Kiyoshi

    2015-01-01

    A taste sensor using lipid-polymer membranes has been developed to evaluate the taste of foods, beverages and medicines. The response of the taste sensor, measured as a change in the membrane potential caused by adsorption (CPA), corresponds to the aftertaste felt by humans. The relationships between the CPA value and the amount of adsorbed taste substances, quinine and iso-α acid (bitterness), and tannic acid (astringency), have been studied so far. However, that of epigallocatechin gallate (EGCg) has not been clarified, although EGCg is abundantly present in green tea as one of its astringent substances. This study aimed at clarifying the response of the taste sensor to EGCg and its relationship with the amount of EGCg adsorbed onto lipid-polymer membranes. The lipid concentration dependence of the CPA value was similar to that of the amount of adsorbed EGCg, indicating a high correlation between the CPA value and the amount of adsorbed EGCg. The CPA value increased with increasing amount of adsorbed EGCg; however, the CPA value showed a tendency of leveling off when the amount of adsorbed EGCg further increased. PMID:25781512

  9. Transmission of large amounts of scientific data using laser technology

    NASA Astrophysics Data System (ADS)

    Isaev, E. A.; Tarasov, P. A.

    2016-08-01

    Currently, the volume of figures generated by different research scientific projects (the Large Hadron Collider (Large Hadron Collider, LHC), The Square Kilometre Array (SKA)), can reach tens of petabytes per day. The only technical solution that allows you to transfer such large amounts of scientific data to the places of their processing is the transfer of information by means of laser technology, using different propagation environment. This article discusses the possibility of data transmission via fiber-optic networks, data transmission using the modulation binary stream of light source by a special LED light source, the neccessity to apply laser technologies for deep space communications, the principle for an unlimited expansion of the capacity of laser data link. Also in this study is shown the need for a substantial increase in data transfer speed via a pre-existing communication networks and via the construction of new channels of communication that will cope with the transfer of very large scale data volumes, taking into account the projected rate of growth.

  10. Very Large Amounts of Radiation are Required to Produce Cancer

    PubMed Central

    Brooks, Antone L.; Hui, T. Edmond; Couch, Lezlie A.

    2007-01-01

    The public fear of radiation is in part driven by the Linear No Threshold Hypothesis (LNTH), or the concept that each and every ionization increases the risk for cancer. Even if this were true, it is important to recognize that the increased risk is very small at low doses and cannot be detected. This paper demonstrates the large number of assumptions and extrapolations needed when using the LNTH to estimate low-dose cancer risk. The manuscript provides information at every level of biological organization suggesting that many of these linear assumptions do not hold. While the initial damage may be produced linearly with dose, the processing of that damage is very non-linear. Finally, the paper provides the unique prospective on radiation-induced cancer, demonstrating that it takes large amounts (total energy) of radiation delivered to large populations to detect an increase in cancer frequency. These observations are supported by both theoretical calculations and examples based on past human radiation exposure. PMID:18648559

  11. Discovering Related Clinical Concepts Using Large Amounts of Clinical Notes.

    PubMed

    Ganesan, Kavita; Lloyd, Shane; Sarkar, Vikren

    2016-01-01

    The ability to find highly related clinical concepts is essential for many applications such as for hypothesis generation, query expansion for medical literature search, search results filtering, ICD-10 code filtering and many other applications. While manually constructed medical terminologies such as SNOMED CT can surface certain related concepts, these terminologies are inadequate as they depend on expertise of several subject matter experts making the terminology curation process open to geographic and language bias. In addition, these terminologies also provide no quantifiable evidence on how related the concepts are. In this work, we explore an unsupervised graphical approach to mine related concepts by leveraging the volume within large amounts of clinical notes. Our evaluation shows that we are able to use a data driven approach to discovering highly related concepts for various search terms including medications, symptoms and diseases. PMID:27656096

  12. Discovering Related Clinical Concepts Using Large Amounts of Clinical Notes

    PubMed Central

    Ganesan, Kavita; Lloyd, Shane; Sarkar, Vikren

    2016-01-01

    The ability to find highly related clinical concepts is essential for many applications such as for hypothesis generation, query expansion for medical literature search, search results filtering, ICD-10 code filtering and many other applications. While manually constructed medical terminologies such as SNOMED CT can surface certain related concepts, these terminologies are inadequate as they depend on expertise of several subject matter experts making the terminology curation process open to geographic and language bias. In addition, these terminologies also provide no quantifiable evidence on how related the concepts are. In this work, we explore an unsupervised graphical approach to mine related concepts by leveraging the volume within large amounts of clinical notes. Our evaluation shows that we are able to use a data driven approach to discovering highly related concepts for various search terms including medications, symptoms and diseases. PMID:27656096

  13. Discovering Related Clinical Concepts Using Large Amounts of Clinical Notes.

    PubMed

    Ganesan, Kavita; Lloyd, Shane; Sarkar, Vikren

    2016-01-01

    The ability to find highly related clinical concepts is essential for many applications such as for hypothesis generation, query expansion for medical literature search, search results filtering, ICD-10 code filtering and many other applications. While manually constructed medical terminologies such as SNOMED CT can surface certain related concepts, these terminologies are inadequate as they depend on expertise of several subject matter experts making the terminology curation process open to geographic and language bias. In addition, these terminologies also provide no quantifiable evidence on how related the concepts are. In this work, we explore an unsupervised graphical approach to mine related concepts by leveraging the volume within large amounts of clinical notes. Our evaluation shows that we are able to use a data driven approach to discovering highly related concepts for various search terms including medications, symptoms and diseases.

  14. Discovering Related Clinical Concepts Using Large Amounts of Clinical Notes

    PubMed Central

    Ganesan, Kavita; Lloyd, Shane; Sarkar, Vikren

    2016-01-01

    The ability to find highly related clinical concepts is essential for many applications such as for hypothesis generation, query expansion for medical literature search, search results filtering, ICD-10 code filtering and many other applications. While manually constructed medical terminologies such as SNOMED CT can surface certain related concepts, these terminologies are inadequate as they depend on expertise of several subject matter experts making the terminology curation process open to geographic and language bias. In addition, these terminologies also provide no quantifiable evidence on how related the concepts are. In this work, we explore an unsupervised graphical approach to mine related concepts by leveraging the volume within large amounts of clinical notes. Our evaluation shows that we are able to use a data driven approach to discovering highly related concepts for various search terms including medications, symptoms and diseases.

  15. Making large amounts of meteorological plots easily accessible to users

    NASA Astrophysics Data System (ADS)

    Lamy-Thepaut, Sylvie; Siemen, Stephan; Sahin, Cihan; Raoult, Baudouin

    2015-04-01

    The European Centre for Medium-Range Weather Forecasts (ECMWF) is an international organisation providing its member organisations with forecasts in the medium time range of 3 to 15 days, and some longer-range forecasts for up to a year ahead, with varying degrees of detail. As part of its mission, ECMWF generates an increasing number of forecast data products for its users. To support the work of forecasters and researchers and to let them make best use of ECMWF forecasts, the Centre also provides tools and interfaces to visualise their products. This allows users to make use of and explore forecasts without having to transfer large amounts of raw data. This is especially true for products based on ECMWF's 50 member ensemble forecast, where some specific processing and visualisation are applied to extract information. Every day, thousands of raw data are being pushed to the ECMWF's interactive web charts application called ecCharts, and thousands of products are processed and pushed to ECMWF's institutional web site ecCharts provides a highly interactive application to display and manipulate recent numerical forecasts to forecasters in national weather services and ECMWF's commercial customers. With ecCharts forecasters are able to explore ECMWF's medium-range forecasts in far greater detail than has previously been possible on the web, and this as soon as the forecast becomes available. All ecCharts's products are also available through a machine-to-machine web map service based on the OGC Web Map Service (WMS) standard. ECMWF institutional web site provides access to a large number of graphical products. It was entirely redesigned last year. It now shares the same infrastructure as ECMWF's ecCharts, and can benefit of some ecCharts functionalities, for example the dashboard. The dashboard initially developed for ecCharts allows users to organise their own collection of products depending on their work flow, and is being further developed. In its first

  16. Knowledge discovery: Extracting usable information from large amounts of data

    SciTech Connect

    Whiteson, R.

    1998-12-31

    The threat of nuclear weapons proliferation is a problem of world wide concern. Safeguards are the key to nuclear nonproliferation and data is the key to safeguards. The safeguards community has access to a huge and steadily growing volume of data. The advantages of this data rich environment are obvious, there is a great deal of information which can be utilized. The challenge is to effectively apply proven and developing technologies to find and extract usable information from that data. That information must then be assessed and evaluated to produce the knowledge needed for crucial decision making. Efficient and effective analysis of safeguards data will depend on utilizing technologies to interpret the large, heterogeneous data sets that are available from diverse sources. With an order-of-magnitude increase in the amount of data from a wide variety of technical, textual, and historical sources there is a vital need to apply advanced computer technologies to support all-source analysis. There are techniques of data warehousing, data mining, and data analysis that can provide analysts with tools that will expedite their extracting useable information from the huge amounts of data to which they have access. Computerized tools can aid analysts by integrating heterogeneous data, evaluating diverse data streams, automating retrieval of database information, prioritizing inputs, reconciling conflicting data, doing preliminary interpretations, discovering patterns or trends in data, and automating some of the simpler prescreening tasks that are time consuming and tedious. Thus knowledge discovery technologies can provide a foundation of support for the analyst. Rather than spending time sifting through often irrelevant information, analysts could use their specialized skills in a focused, productive fashion. This would allow them to make their analytical judgments with more confidence and spend more of their time doing what they do best.

  17. Expert system shell to reason on large amounts of data

    NASA Technical Reports Server (NTRS)

    Giuffrida, Gionanni

    1994-01-01

    The current data base management systems (DBMS's) do not provide a sophisticated environment to develop rule based expert systems applications. Some of the new DBMS's come with some sort of rule mechanism; these are active and deductive database systems. However, both of these are not featured enough to support full implementation based on rules. On the other hand, current expert system shells do not provide any link with external databases. That is, all the data are kept in the system working memory. Such working memory is maintained in main memory. For some applications the reduced size of the available working memory could represent a constraint for the development. Typically these are applications which require reasoning on huge amounts of data. All these data do not fit into the computer main memory. Moreover, in some cases these data can be already available in some database systems and continuously updated while the expert system is running. This paper proposes an architecture which employs knowledge discovering techniques to reduce the amount of data to be stored in the main memory; in this architecture a standard DBMS is coupled with a rule-based language. The data are stored into the DBMS. An interface between the two systems is responsible for inducing knowledge from the set of relations. Such induced knowledge is then transferred to the rule-based language working memory.

  18. Determination of small and large amounts of fluorine in rocks

    USGS Publications Warehouse

    Grimaldi, F.S.; Ingram, B.; Cuttitta, F.

    1955-01-01

    Gelatinous silica and aluminum ions retard the distillation of fluorine in the Willard and Winter distillation method. A generally applicable, simple method for the determination of fluorine in rocks containing aluminum or silicon or both as major constituents was desired. In the procedure developed, the sample is fused with a mixture of sodium carbonate and zinc oxide, leached with water, and filtered. The residue is granular and retains nearly all of the silica. The fluorine in the filtrate is distilled directly from a perchloric acid-phosphoric acid mixture. Phosphoric acid permits the quantitative distillation of fluorine in the presence of much aluminum at the usual distillation temperature and without the collection of large volumes of distillate. The fluorine is determined either by microtitration with thorium nitrate or colorimetrically with thoron. The procedure is rapid and has yielded excellent results on silicate rocks and on samples from the aluminum phosphate (leached) zone of the Florida phosphate deposits.

  19. Comparison Analysis among Large Amount of SNS Sites

    NASA Astrophysics Data System (ADS)

    Toriumi, Fujio; Yamamoto, Hitoshi; Suwa, Hirohiko; Okada, Isamu; Izumi, Kiyoshi; Hashimoto, Yasuhiro

    In recent years, application of Social Networking Services (SNS) and Blogs are growing as new communication tools on the Internet. Several large-scale SNS sites are prospering; meanwhile, many sites with relatively small scale are offering services. Such small-scale SNSs realize small-group isolated type of communication while neither mixi nor MySpace can do that. However, the studies on SNS are almost about particular large-scale SNSs and cannot analyze whether their results apply for general features or for special characteristics on the SNSs. From the point of view of comparison analysis on SNS, comparison with just several types of those cannot reach a statistically significant level. We analyze many SNS sites with the aim of classifying them by using some approaches. Our paper classifies 50,000 sites for small-scale SNSs and gives their features from the points of network structure, patterns of communication, and growth rate of SNS. The result of analysis for network structure shows that many SNS sites have small-world attribute with short path lengths and high coefficients of their cluster. Distribution of degrees of the SNS sites is close to power law. This result indicates the small-scale SNS sites raise the percentage of users with many friends than mixi. According to the analysis of their coefficients of assortativity, those SNS sites have negative values of assortativity, and that means users with high degree tend to connect users with small degree. Next, we analyze the patterns of user communication. A friend network of SNS is explicit while users' communication behaviors are defined as an implicit network. What kind of relationships do these networks have? To address this question, we obtain some characteristics of users' communication structure and activation patterns of users on the SNS sites. By using new indexes, friend aggregation rate and friend coverage rate, we show that SNS sites with high value of friend coverage rate activate diary postings

  20. Adsorbent materials for carbon dioxide capture from large anthropogenic point sources.

    PubMed

    Choi, Sunho; Drese, Jeffrey H; Jones, Christopher W

    2009-01-01

    Since the time of the industrial revolution, the atmospheric CO(2) concentration has risen by nearly 35 % to its current level of 383 ppm. The increased carbon dioxide concentration in the atmosphere has been suggested to be a leading contributor to global climate change. To slow the increase, reductions in anthropogenic CO(2) emissions are necessary. Large emission point sources, such as fossil-fuel-based power generation facilities, are the first targets for these reductions. A benchmark, mature technology for the separation of dilute CO(2) from gas streams is via absorption with aqueous amines. However, the use of solid adsorbents is now being widely considered as an alternative, potentially less-energy-intensive separation technology. This Review describes the CO(2) adsorption behavior of several different classes of solid carbon dioxide adsorbents, including zeolites, activated carbons, calcium oxides, hydrotalcites, organic-inorganic hybrids, and metal-organic frameworks. These adsorbents are evaluated in terms of their equilibrium CO(2) capacities as well as other important parameters such as adsorption-desorption kinetics, operating windows, stability, and regenerability. The scope of currently available CO(2) adsorbents and their critical properties that will ultimately affect their incorporation into large-scale separation processes is presented.

  1. Challenges and strategies in the preparation of large-volume polymer-based monolithic chromatography adsorbents.

    PubMed

    Ongkudon, Clarence M; Kansil, Tamar; Wong, Charlotte

    2014-03-01

    To date, the number of published reports on the large-volume preparation of polymer-based monolithic chromatography adsorbents is still lacking and is of great importance. Many critical factors need to be considered when manufacturing a large-volume polymer-based monolith for chromatographic applications. Structural integrity, validity, and repeatability are thought to be the key factors determining the usability of a large-volume monolith in a separation process. In this review, we focus on problems and solutions pertaining to heat dissipation, pore size distribution, "wall channel" effect, and mechanical strength in monolith preparation. A template-based method comprising sacrificial and nonsacrificial techniques is possibly the method of choice due to its precise control over the porous structure. However, additional expensive steps are usually required for the template removal. Other strategies in monolith preparation are also discussed.

  2. A simple biosynthetic pathway for large product generation from small substrate amounts

    NASA Astrophysics Data System (ADS)

    Djordjevic, Marko; Djordjevic, Magdalena

    2012-10-01

    A recently emerging discipline of synthetic biology has the aim of constructing new biosynthetic pathways with useful biological functions. A major application of these pathways is generating a large amount of the desired product. However, toxicity due to the possible presence of toxic precursors is one of the main problems for such production. We consider here the problem of generating a large amount of product from a potentially toxic substrate. To address this, we propose a simple biosynthetic pathway, which can be induced in order to produce a large number of the product molecules, by keeping the substrate amount at low levels. Surprisingly, we show that the large product generation crucially depends on fast non-specific degradation of the substrate molecules. We derive an optimal induction strategy, which allows as much as three orders of magnitude increase in the product amount through biologically realistic parameter values. We point to a recently discovered bacterial immune system (CRISPR/Cas in E. coli) as a putative example of the pathway analysed here. We also argue that the scheme proposed here can be used not only as a stand-alone pathway, but also as a strategy to produce a large amount of the desired molecules with small perturbations of endogenous biosynthetic pathways.

  3. Regenerative adsorbent heat pump

    NASA Technical Reports Server (NTRS)

    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.

  4. Study on Properties of Environment-friendly Concrete Containing Large Amount of Industrial by-products

    NASA Astrophysics Data System (ADS)

    Fujiwara, H.; Maruoka, M.; Sadayama, C.; Nemoto, M.; Yoshikawa, K.; Yamaji, M.

    2015-11-01

    This study aims to reduce CO2 discharged from the cement and concrete industries by effective use of industrial by-products, such as fly ash, blast furnace slag, and so on. In this paper, the properties of concrete containing large amount of industrial by-products and very small amount of alkaline activator including cement or sludge from ready mixed concrete plant are analyzed. As the result, it was confirmed that concretes containing large amount of industrial by-products can achieve sufficient compressive strength. However, these concretes showed poor frost resistance. It was thought that the reason was coarsening of air void system and this caused their poor frost resistance. Therefore, in order to micronize the air void system and improve frost resistance, the combination of air entraining agent and antifoaming agent was applied. By this method, it was confirmed that the frost resistance of some these concrete improved. In this study, other properties of these concretes, such as fresh properties and other durability were evaluated and it was confirmed that these concretes show sufficient properties.

  5. Tritium fuel cycle in ITER and DEMO: Issues in handling large amount of fuel

    NASA Astrophysics Data System (ADS)

    Tanabe, T.

    2013-07-01

    Since tritium resources are very limited, economical conversion of fusion energy to electricity and/or heat must have an enough margin to keep self-fuel-sufficiency and simultaneously ensure tritium safety. To realize this, tritium inventory in reactor systems, which use ˜1017 Bq (a few kg) of tritium, should be kept as small as possible, under strict accountancy or regulation of a few tens Bq (˜pg). In present tokamaks, however, hydrogen retention rate is significantly large, i.e. more than 5% of fueled hydrogen is continuously piled up in their vacuum vessels, which must not be allowed in a reactor. Moreover, both fuelling and burning efficiencies are very poor, only a few % or less. Accordingly, huge amount of tritium fuel must be recycled. In the paper, after the introduction of tritium as a hydrogen radioisotope, important issues to establish safe and economical tritium fuel cycle for a fusion reactor will be summarized considering the handling of large amounts of tritium, i.e. confinement, leakage, contamination, permeation, regulation and tritium accountancy.

  6. Rapid and effective DNA extraction method with bead grinding for a large amount of fungal DNA.

    PubMed

    Watanabe, M; Lee, K; Goto, K; Kumagai, S; Sugita-Konishi, Y; Hara-Kudo, Y

    2010-06-01

    To identify a rapid method for extracting a large amount of DNA from fungi associated with food hygiene, extraction methods were compared using fungal pellets formed rapidly in liquid media. Combinations of physical and chemical methods or commercial kits were evaluated with 3 species of yeast, 10 species of ascomycetous molds, and 4 species of zygomycetous molds. Bead grinding was the physical method, followed by chemical methods involving sodium dodecyl sulfate (SDS), cetyl trimethyl ammonium bromide (CTAB), and benzyl chloride and two commercial kits. Quantity was calculated by UV absorbance at 260 nm, quality was determined by the ratio of UV absorbance at 260 and 280 nm, and gene amplifications and electrophoresis profiles of whole genomes were analyzed. Bead grinding with the SDS method was the most effective for DNA extraction for yeasts and ascomycetous molds, and bead grinding with the CTAB method was most effective with zygomycetous molds. For both groups of molds, bead grinding with the CTAB method was the best approach for DNA extraction. Because this combination also is relatively effective for yeasts, it can be used to extract a large amount of DNA from a wide range of fungi. The DNA extraction methods are useful for developing gene indexes to identify fungi with molecular techniques, such as DNA fingerprinting.

  7. Application of ultradisperse magnetic adsorbents for removal of small concentrations of pollutants from large volumes of water

    NASA Astrophysics Data System (ADS)

    Nechitailo, Galina S.; Kuznetsov, Anatoli; Kuznetsov, Oleg

    2016-07-01

    Pollution of natural bodies of water (rivers, lakes, ground water, etc) is unfortunately very common, both from natural sources like volcanic activity; and, even more importantly, from human activity, including disposal of industrial and municipal waste, mining, etc. Many toxic substances are harmful for humans and other organisms even in very low concentrations (e.g., less than 1 µg/L of cadmium is harmful, for Hg it is 0.5 µg/L, for phenol - 1 µg/L), and can remain in water for decades or longer. Cleaning large volumes of water even from low concentrations of pollutants is a challenging technological task and is very expensive. We propose to use suspension of ultradisperse magnetic adsorbents, for example, nanostructured ferro-carbon particles, produced by plasmachemical technique, for removing small concentrations of pollutants from large volumes of water. The suspension is introduced into the water. Due to their small sizes and densities similar to water (we measured the density of FC-4 ferro-carbon to be about 1 g/cm3; presumably due to porosity) the particles do not sediment for a long time (hours, days or longer), move due to Brownian motion and adsorb a variety of substances from the water. The particle surface can be modified to provide selectivity of the adsorption. Sorption capacities of ferro-carbon adsorbents is in dozens of percent. Therefore, to collect 1 kg of a pollutant, 2 to 20 kg of the adsorbents is required. Then the particles with the adsorbed contaminant can be collected (e.g., downstream of the river) using a variety of magnetic traps. The traps can consist of ferromagnetic wires and permanent magnets, a variety of simple and inexpensive designs are available. As a model system, the kinetics of adsorption of a highly diluted (0.002 mg/ml) aqueous solution of a low molecular weight compound (toluidine blue) by a small concentration of a ferro-carbon powder (FC-4) was studied by spectrophotometry. Before each measurement, the particles

  8. Geo-reCAPTCHA: Crowdsourcing large amounts of geographic information from earth observation data

    NASA Astrophysics Data System (ADS)

    Hillen, Florian; Höfle, Bernhard

    2015-08-01

    The reCAPTCHA concept provides a large amount of valuable information for various applications. First, it provides security, e.g., for a form on a website, by means of a test that only a human could solve. Second, the effort of the user for this test is used to generate additional information, e.g., digitization of books or identification of house numbers. In this work, we present a concept for adapting the reCAPTCHA idea to create user-generated geographic information from earth observation data, and the requirements during the conception and implementation are depicted in detail. Furthermore, the essential parts of a Geo-reCAPTCHA system are described, and afterwards transferred, to a prototype implementation. An empirical user study is conducted to investigate the Geo-reCAPTCHA approach, assessing time and quality of the resulting geographic information. Our results show that a Geo-reCAPTCHA can be solved by the users of our study on building digitization in a short amount of time (19.2 s on average) with an overall average accuracy of the digitizations of 82.2%. In conclusion, Geo-reCAPTCHA has the potential to be a reasonable alternative to the typical reCAPTCHA, and to become a new data-rich channel of crowdsourced geographic information.

  9. Analytics to Better Interpret and Use Large Amounts of Heterogeneous Data

    NASA Astrophysics Data System (ADS)

    Mathews, T. J.; Baskin, W. E.; Rinsland, P. L.

    2014-12-01

    Data scientists at NASA's Atmospheric Science Data Center (ASDC) are seasoned software application developers who have worked with the creation, archival, and distribution of large datasets (multiple terabytes and larger). In order for ASDC data scientists to effectively implement the most efficient processes for cataloging and organizing data access applications, they must be intimately familiar with data contained in the datasets with which they are working. Key technologies that are critical components to the background of ASDC data scientists include: large RBMSs (relational database management systems) and NoSQL databases; web services; service-oriented architectures; structured and unstructured data access; as well as processing algorithms. However, as prices of data storage and processing decrease, sources of data increase, and technologies advance - granting more people to access to data at real or near-real time - data scientists are being pressured to accelerate their ability to identify and analyze vast amounts of data. With existing tools this is becoming exceedingly more challenging to accomplish. For example, NASA Earth Science Data and Information System (ESDIS) alone grew from having just over 4PBs of data in 2009 to nearly 6PBs of data in 2011. This amount then increased to roughly10PBs of data in 2013. With data from at least ten new missions to be added to the ESDIS holdings by 2017, the current volume will continue to grow exponentially and drive the need to be able to analyze more data even faster. Though there are many highly efficient, off-the-shelf analytics tools available, these tools mainly cater towards business data, which is predominantly unstructured. Inadvertently, there are very few known analytics tools that interface well to archived Earth science data, which is predominantly heterogeneous and structured. This presentation will identify use cases for data analytics from an Earth science perspective in order to begin to identify

  10. DataPipeline: automated importing and fitting of large amounts of biophysical data.

    PubMed

    Farrell, Damien; Nielsen, Jens Erik

    2012-11-01

    Raw data from experiments across the biological sciences comes in a large variety of text formats. In small or medium sized laboratories researchers often use an assorted collection of software to interpret, fit, and visualize their data. The spreadsheet is commonly the core component of such a workflow. The limitations of such programs for large amounts of heterogeneous data can be frustrating. We report the construction of DataPipeline, a desktop and command-line application that automates the tasks of importing, fitting, and plotting of text-based data. The software is designed to simplify the process of importing text data from various sources using simple configuration files to describe raw file formats. Once imported, curve fitting can be performed using custom fitting models designed by the user inside the application. Fitted parameters can be grouped together as new datasets to be fitted to other models and experimental uncertainties propagated to give error estimates. This software will be useful for processing of data from high through-put biological experiments or for rapid visualization of pilot data without the need for a chain of different programs to carry out each step. DataPipeline and source code is available under an open source license. The software can be freely downloaded at http://code.google.com/p/peat/downloads/list.

  11. High-speed readout method of ID information on a large amount of electronic tags

    NASA Astrophysics Data System (ADS)

    Nagate, Wataru; Sasabe, Masahiro; Nakano, Hirotaka

    2006-10-01

    An electronic tag such as RFID is expected to create new services that cannot be achieved by the traditional bar code. Specifically, in a distribution system, simultaneous readout method of a large amount of electronic tags embedded in products is required to reduce costs and time. In this paper, we propose novel methods, called Response Probability Control (RPC), to accomplish this requirement. In RPC, a reader firstly sends an ID request to electronic tags in its access area. It succeeds reading information on a tag only if other tags do not respond. To improve the readout efficiency, the reader appropriately controls the response probability in accordance with the number of tags. However, this approach cannot entirely avoid a collision of multiple responses. When a collision occurs, ID information is lost. To reduce the amount of lost data, we divide the ID registration process into two steps. The reader first gathers the former part of the original ID, called temporal ID, according to the above method. After obtaining the temporal ID, it sequentially collects the latter part of ID, called remaining ID, based on the temporal ID. Note that we determine the number of bits of a temporal ID in accordance with the number of tags in the access area so that each tag can be distinguishable. Through simulation experiments, we evaluate RPC in terms of the readout efficiency. Simulation results show that RPC can accomplish the readout efficiency 1.17 times higher than the traditional method where there are a thousand of electronic tags whose IDs are 128 bits.

  12. Mesoporous Silica Nanoparticles as an Adsorbent for Preconcentration and Determination of Trace Amount of Nickel in Environmental Samples by Atom Trap Flame Atomic Absorption Spectrometry

    NASA Astrophysics Data System (ADS)

    Shirkhanloo, H.; Falahnejad, M.; Zavvar Mousavi, H.

    2016-01-01

    A rapid enrichment method based on solid-phase extraction (SPE) has been established for preconcentration and separation of trace Ni(II) ions in water samples prior to their determination by atom trap flame atomic absorption spectrometry. A column filled with bulky NH2-UVM7 was used as the novel adsorbent. Under optimal conditions, the linear range, limit of detection (LOD), and preconcentration factor (PF) were 3-92 μg/L, 0.8 μg/L, and 100, respectively. The validity of the method was checked by the standard reference material.

  13. How to extract clinically useful information from large amount of dialysis related stored data.

    PubMed

    Vito, Domenico; Casagrande, Giustina; Bianchi, Camilla; Costantino, Maria L

    2015-01-01

    The basic storage infrastructure used to gather data from the technological evolution also in the healthcare field was leading to the storing into public or private repository of even higher quantities of data related to patients and their pathological evolution. Big data techniques are spreading also in medical research. By these techniques is possible extract information from complex heterogeneous sources, realizing longitudinal studies focused to correlate the patient status with biometric parameters. In our work we develop a common data infrastructure involving 4 clinical dialysis centers between Lombardy and Switzerland. The common platform has been build to store large amount of clinical data related to 716 dialysis session of 70 patient. The platform is made up by a combination of a MySQL(®) database (Dialysis Database) and a MATLAB-based mining library (Dialysis MATlib). A statistical analysis of these data has been performed on the data gathered. These analyses led to the development of two clinical indexes, representing an example of transformation of big data into clinical information. PMID:26737858

  14. The development of transgenic mice for the expression of large amounts of human lysozyme in milk.

    PubMed

    Wu, Xiaojie; Lin, Yanli; Xi, Yongyi; Shao, Zhenlu; Zhou, Yanrong; Liu, Fang; Chen, Hongxing

    2014-06-01

    Human lysozyme (hLYZ) has important potential applications as antimicrobial medicine and food additive. To develop a robust expression vector that ensures expression of large amounts of hLYZ in milk, here a 26,267 bp chimeric mouse whey acidic protein (mWAP)::hLYZ cassette was constructed and used as a mammary gland-specific expression vector, in which a 3,010 bp genomic sequence in the 24,466 bp mWAP gene locus was substituted by a 4,811 bp genomic sequence of hLYZ, exactly from the start codon to the stop codon. Corresponding transgenic mice were generated, and enzymatically-active hLYZ was expressed at 18.4-35 g l(-1) in the milk of most transgenic mouse lines. Our transgenic mice carrying chimeric mWAP::hLYZ represent a model system for cost-effective production of hLYZ. PMID:24563307

  15. Biological soil crusts emit large amounts of NO and HONO affecting the nitrogen cycle in drylands

    NASA Astrophysics Data System (ADS)

    Tamm, Alexandra; Wu, Dianming; Ruckteschler, Nina; Rodríguez-Caballero, Emilio; Steinkamp, Jörg; Meusel, Hannah; Elbert, Wolfgang; Behrendt, Thomas; Sörgel, Matthias; Cheng, Yafang; Crutzen, Paul J.; Su, Hang; Pöschl, Ulrich; Weber, Bettina

    2016-04-01

    Dryland systems currently cover ˜40% of the world's land surface and are still expanding as a consequence of human impact and global change. In contrast to that, information on their role in global biochemical processes is limited, probably induced by the presumption that their sparse vegetation cover plays a negligible role in global balances. However, spaces between the sparse shrubs are not bare, but soils are mostly covered by biological soil crusts (biocrusts). These biocrust communities belong to the oldest life forms, resulting from an assembly between soil particles and cyanobacteria, lichens, bryophytes, and algae plus heterotrophic organisms in varying proportions. Depending on the dominating organism group, cyanobacteria-, lichen-, and bryophyte-dominated biocrusts are distinguished. Besides their ability to restrict soil erosion they fix atmospheric carbon and nitrogen, and by doing this they serve as a nutrient source in strongly depleted dryland ecosystems. In this study we show that a fraction of the nitrogen fixed by biocrusts is metabolized and subsequently returned to the atmosphere in the form of nitric oxide (NO) and nitrous acid (HONO). These gases affect the radical formation and oxidizing capacity within the troposphere, thus being of particular interest to atmospheric chemistry. Laboratory measurements using dynamic chamber systems showed that dark cyanobacteria-dominated crusts emitted the largest amounts of NO and HONO, being ˜20 times higher than trace gas fluxes of nearby bare soil. We showed that these nitrogen emissions have a biogenic origin, as emissions of formerly strongly emitting samples almost completely ceased after sterilization. By combining laboratory, field, and satellite measurement data we made a best estimate of global annual emissions amounting to ˜1.1 Tg of NO-N and ˜0.6 Tg of HONO-N from biocrusts. This sum of 1.7 Tg of reactive nitrogen emissions equals ˜20% of the soil release under natural vegetation according

  16. Behavioral responses of cotton mice (Peromyscus gossypinus) to large amounts of coarse woody debris.

    SciTech Connect

    Hinkleman, Travis M.

    2004-08-01

    Hinkleman, Travis M. 2004. MS Thesis. Clemson University, Clemson, South Carolina. 62 pp. Coarse woody debris (CWD) is any log, snag, or downed branch >10 cm in diameter. As a major structural feature of forest ecosystems, CWD serves as an important habitat component for a variety of organisms. Rodents frequently use CWD for travel routes and daytime refugia. Although rodents are known to use CWD extensively and selectively, the use and selection of CWD by rodents may vary according to the abundance of CWD. The purpose of this project was to determine the effect of CWD abundance on the habitat use patterns of a common terrestrial rodent, the cotton mouse (Peromyscus gossypinus). I tracked cotton mice with fluorescent pigments and radiotelemetry in 6 plots, situated in loblolly pine (Pinus taeda) stands, with manipulated levels of woody debris. Treatment plots had 6x the amount of woody debris as control plots. I determined log use and movement patterns from the paths produced by powder-tracking, and I identified daytime refugia by radio-tracking. Travel along logs was almost exclusively associated with the surface of logs (91%). The proportion of a movement path associated with logs was not the best predictor of path complexity; rather, the sex of the individual was the only significant indicator of relative displacement (i.e., males moved farther from the point of release than females) and vegetation cover was the only significant predictor of mean turning angle (i.e., increasing vegetation cover yielded more convoluted paths). Mice used logs to a greater extent on treatment plots (23.7%) than mice on control plots (4.8%). Mice on treatment plots used logs with less decay, less ground contact, and more bark than logs used by mice on control plots. Differences in log use patterns were largely a result of the attributes of available logs, but mice used logs selectively on treatment plots. Refuges were highly associated with woody debris, including refuges in rotting

  17. Effect of large amounts of dihydroxyacetone in the diet of rats.

    NASA Technical Reports Server (NTRS)

    Shapira, J.

    1972-01-01

    Experiments in which dihydroxyacetone (DHA) was used as nutrient for growing rats have not fulfilled the expectation that DHA could be used as a significant portion of the diet. Any attempt to treat major cerebral damage by prolonged administration of DHA is strongly contraindicated. For this reason, regenerated formose mixtures containing appreciable amounts of DHA will not be suitable as a significant portion of the diet for the crews of long-duration space missions.

  18. The ATLAS Eventindex: an event catalogue for experiments collecting large amounts of data

    NASA Astrophysics Data System (ADS)

    Barberis, D.; Cranshaw, J.; Dimitrov, G.; Favareto, A.; Fernández Casaní, Á.; González de la Hoz, S.; Hřivnáč, J.; Malon, D.; Nowak, M.; Salt Cairols, J.; Sánchez, J.; Sorokoletov, R.; Zhang, Q.; Atlas Collaboration

    2014-06-01

    Modern scientific experiments collect vast amounts of data that must be catalogued to meet multiple use cases and search criteria. In particular, high-energy physics experiments currently in operation produce several billion events per year. A database with the references to the files including each event in every stage of processing is necessary in order to retrieve the selected events from data storage systems. The ATLAS EventIndex project is studying the best way to store the necessary information using modern data storage technologies (Hadoop, HBase etc.) that allow saving in memory key-value pairs and select the best tools to support this application from the point of view of performance, robustness and ease of use. This paper describes the initial design and performance tests and the project evolution towards deployment and operation during 2014.

  19. 26 CFR 301.6867-1 - Presumptions where owner of large amount of cash is not identified.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 26 Internal Revenue 18 2011-04-01 2011-04-01 false Presumptions where owner of large amount of cash is not identified. 301.6867-1 Section 301.6867-1 Internal Revenue INTERNAL REVENUE SERVICE, DEPARTMENT OF THE TREASURY (CONTINUED) PROCEDURE AND ADMINISTRATION PROCEDURE AND ADMINISTRATION Jeopardy, Bankruptcy, and Receiverships Jeopardy §...

  20. Draft Genome Sequence of Rheinheimera sp. F8, a Biofilm-Forming Strain Which Produces Large Amounts of Extracellular DNA

    PubMed Central

    Szewzyk, Ulrich

    2016-01-01

    Rheinheimera sp. strain F8 is a biofilm-forming gammaproteobacterium that has been found to produce large amounts of filamentous extracellular DNA. Here, we announce the de novo assembly of its genome. It is estimated to be 4,464,511 bp in length, with 3,970 protein-coding sequences and 92 RNA-coding sequences. PMID:26966195

  1. 18O depletion in monsoon rain relates to large scale organized convection rather than the amount of rainfall.

    PubMed

    Lekshmy, P R; Midhun, M; Ramesh, R; Jani, R A

    2014-07-11

    Oxygen isotopic variations in rainfall proxies such as tree rings and cave calcites from South and East Asia have been used to reconstruct past monsoon variability, mainly through the amount effect: the observed (18)O depletion of rain with increasing amount, manifested as a negative correlation of the monthly amount of tropical rain with its δ(18)O, both measured at the same station. This relation exhibits a significant spatial variability, and at some sites (especially North-East and peninsular India), the rainfall proxies are not interpretable by this effect. We show here that relatively higher (18)O-depletion in monsoon rain is not related necessarily to its amount, but rather, to large scale organized convection. Presenting δ(18)O analyses of ~654 samples of daily rain collected during summer 2012 across 9 stations in Kerala, southern India, we demonstrate that although the cross correlations between the amounts of rainfall in different stations is insignificant, the δ(18)O values of rain exhibit highly coherent variations (significant at P = 0.05). Significantly more (18)O-depletion in the rain is caused by clouds only during events with a large spatial extent of clouds observable over in the south eastern Arabian Sea.

  2. 18O depletion in monsoon rain relates to large scale organized convection rather than the amount of rainfall

    PubMed Central

    Lekshmy, P. R.; Midhun, M.; Ramesh, R.; Jani, R. A.

    2014-01-01

    Oxygen isotopic variations in rainfall proxies such as tree rings and cave calcites from South and East Asia have been used to reconstruct past monsoon variability, mainly through the amount effect: the observed 18O depletion of rain with increasing amount, manifested as a negative correlation of the monthly amount of tropical rain with its δ18O, both measured at the same station. This relation exhibits a significant spatial variability, and at some sites (especially North-East and peninsular India), the rainfall proxies are not interpretable by this effect. We show here that relatively higher 18O-depletion in monsoon rain is not related necessarily to its amount, but rather, to large scale organized convection. Presenting δ18O analyses of ~654 samples of daily rain collected during summer 2012 across 9 stations in Kerala, southern India, we demonstrate that although the cross correlations between the amounts of rainfall in different stations is insignificant, the δ18O values of rain exhibit highly coherent variations (significant at P = 0.05). Significantly more 18O-depletion in the rain is caused by clouds only during events with a large spatial extent of clouds observable over in the south eastern Arabian Sea. PMID:25012535

  3. Extensive Recombination Due to Heteroduplexes Generates Large Amounts of Artificial Gene Fragments during PCR

    PubMed Central

    Liu, Jia; Song, Hongshuo; Liu, Donglai; Zuo, Tao; Lu, Fengmin; Zhuang, Hui; Gao, Feng

    2014-01-01

    Artificial recombinants can be generated during PCR when more than two genetically distinct templates coexist in a single PCR reaction. These recombinant amplicons can lead to the false interpretation of genetic diversity and incorrect identification of biological phenotypes that do not exist in vivo. We investigated how recombination between 2 or 35 genetically distinct HIV-1 genomes was affected by different PCR conditions using the parallel allele-specific sequencing (PASS) assay and the next generation sequencing method. In a standard PCR condition, about 40% of amplicons in a PCR reaction were recombinants. The high recombination frequency could be significantly reduced if the number of amplicons in a PCR reaction was below a threshold of 1013–1014 using low thermal cycles, fewer input templates, and longer extension time. Heteroduplexes (each DNA strand from a distinct template) were present at a large proportion in the PCR products when more thermal cycles, more templates, and shorter extension time were used. Importantly, the majority of recombinants were identified in heteroduplexes, indicating that the recombinants were mainly generated through heteroduplexes. Since prematurely terminated extension fragments can form heteroduplexes by annealing to different templates during PCR amplification, recombination has a better chance to occur with samples containing different genomes when the number of amplicons accumulate over the threshold. New technologies are warranted to accurately characterize complex quasispecies gene populations. PMID:25211143

  4. Three horizontal muscle surgery for large-angle infantile esotropia: validation of a table of amounts of surgery

    PubMed Central

    Camuglia, J E; Walsh, M J; Gole, G A

    2011-01-01

    Purpose To validate a table of amounts of three horizontal muscle surgery in patients with large-angle infantile esotropia (≥60 prism dioptres, PD). Methods A prospective interventional case series reporting the postoperative alignment of 51 patients (27 male, 24 female) over a 15-year period was conducted. Surgery amounts were according to a published table developed on a previous patient cohort (n=49), using bilateral medial rectus recession with graded unilateral lateral rectus resection. Kaplan–Meier life-table survival curves were formulated for success to orthotropia (±10 PD) after one and subsequent horizontal muscle surgeries for up to 8 years follow-up. Results The median preoperative deviation was 65 PD (range 60–80 PD) and median age at surgery was 11.8 months (range 5.1 months–3.6 years). Surgical success to orthotropia (±10 PD) after one surgery was 100% at 2 months, 95.7% at 6 months, 91.3% at 12 months, 77.8% at 4 years, and 73.6% at 8 years. Postoperative failure requiring further horizontal surgery occurred in 17.6% (residual esotropia 4, consecutive exotropia 5). Conclusions Our second cohort has reproduced the success rate of the previous cohort (77.8% vs 77.1% at 4 years). If the published table of surgical amounts is used, three horizontal muscle surgery in large-angle infantile esotropia (≥60 PD) appears to have a good long-term success rate, and does not lead to the high rates of either residual esotropia or consecutive exotropia reported by others in the literature. PMID:21818127

  5. Adsorbent phosphates

    NASA Technical Reports Server (NTRS)

    Watanabe, S.

    1983-01-01

    An adsorbent which uses as its primary ingredient phosphoric acid salts of zirconium or titanium is presented. Production methods are discussed and several examples are detailed. Measurements of separating characteristics of some gases using the salts are given.

  6. Impacts of Large Amounts of Wind Power on Design and Operation of Power Systems; Results of IEA Collaboration

    SciTech Connect

    Parsons, B.; Ela, E.; Holttinen, H.; Meibom, P.; Orths, A.; O'Malley, M.; Ummels, B. C.; Tande, J.; Estanqueiro, A.; Gomez, E.; Smith, J. C.

    2008-06-01

    There are a multitude of studies completed and ongoing related to the cost of wind integration. However, the results are not easy to compare. An international forum for exchange of knowledge of power system impacts of wind power has been formed under the IEA Implementing Agreement on Wind Energy. IEA WIND R&D Task 25 on “Design and Operation of Power Systems with Large Amounts of Wind Power” produced a state-of-the-art report in October 2007, where the most relevant wind-power grid integration studies were analyzed, especially regarding methodologies and input data. This paper summarizes the results from 18 case studies, with discussion on differences in methodology as well as issues that have been identified to impact the cost of wind integration.

  7. Precisions Measurement for the Grasp of Welding Deformation amount of Time Series for Large-Scale Industrial Products

    NASA Astrophysics Data System (ADS)

    Abe, R.; Hamada, K.; Hirata, N.; Tamura, R.; Nishi, N.

    2015-05-01

    As well as the BIM of quality management in the construction industry, demand for quality management of the manufacturing process of the member is higher in shipbuilding field. The time series of three-dimensional deformation of the each process, and are accurately be grasped strongly demanded. In this study, we focused on the shipbuilding field, will be examined three-dimensional measurement method. The shipyard, since a large equipment and components are intricately arranged in a limited space, the installation of the measuring equipment and the target is limited. There is also the element to be measured is moved in each process, the establishment of the reference point for time series comparison is necessary to devise. In this paper will be discussed method for measuring the welding deformation in time series by using a total station. In particular, by using a plurality of measurement data obtained from this approach and evaluated the amount of deformation of each process.

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

    PubMed

    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

  9. High Reynolds Number Investigation of a Flush-Mounted, S-Duct Inlet With Large Amounts of Boundary Layer Ingestion

    NASA Technical Reports Server (NTRS)

    Berrier, Bobby L.; Carter, Melissa B.; Allan, Brian G.

    2005-01-01

    An experimental investigation of a flush-mounted, S-duct inlet with large amounts of boundary layer ingestion has been conducted at Reynolds numbers up to full scale. The study was conducted in the NASA Langley Research Center 0.3-Meter Transonic Cryogenic Tunnel. In addition, a supplemental computational study on one of the inlet configurations was conducted using the Navier-Stokes flow solver, OVERFLOW. Tests were conducted at Mach numbers from 0.25 to 0.83, Reynolds numbers (based on aerodynamic interface plane diameter) from 5.1 million to 13.9 million (full-scale value), and inlet mass-flow ratios from 0.29 to 1.22, depending on Mach number. Results of the study indicated that increasing Mach number, increasing boundary layer thickness (relative to inlet height) or ingesting a boundary layer with a distorted profile decreased inlet performance. At Mach numbers above 0.4, increasing inlet airflow increased inlet pressure recovery but also increased distortion. Finally, inlet distortion was found to be relatively insensitive to Reynolds number, but pressure recovery increased slightly with increasing Reynolds number.

  10. Human eosinophils express, relative to other circulating leukocytes, large amounts of secretory 14-kD phospholipase A2.

    PubMed

    Blom, M; Tool, A T; Wever, P C; Wolbink, G J; Brouwer, M C; Calafat, J; Egesten, A; Knol, E F; Hack, C E; Roos, D; Verhoeven, A J

    1998-04-15

    Human eosinophils perform several functions dependent on phospholipase A2 (PLA2) activity, most notably the synthesis of platelet-activating factor (PAF) and leukotriene C4 (LTC4). Several forms of PLA2 have been identified in mammalian cells. In the present study, the 14-kD, secretory form of PLA2 was detected in human eosinophils by immunocytochemical staining with the specific monoclonal antibody (MoAb) 4A1. In contrast, preparations of neutrophils, monocytes, lymphocytes, and basophils did not show detectable staining. With two MoAbs in a sandwich enzyme-linked immunosorbent assay (ELISA), large amounts of sPLA2 were detected in lysates of eosinophils, that were 20-fold to 100-fold higher than in the other circulating leukocytes (ie, neutrophils, basophils, monocytes, and lymphocytes). In addition, with a commercially available sPLA2 activity assay kit, we were able to show high activity of sPLA2 in human eosinophils relative to neutrophils. Investigations at the ultrastructural level showed that sPLA2 in eosinophils is mainly located in specific granules. Immunoelectron microscopy also visualized sPLA2 within phagosomes after addition of opsonized particles to the eosinophils. However, sPLA2 was not detected in the cell-free supernatants of activated eosinophils, in contrast to eosinophil-cationic protein (ECP), which colocalizes with sPLA2 in resting eosinophils. These findings warrant further studies into the role of sPLA2 in eosinophil function.

  11. Soil sampling and isolation of extracellular DNA from large amount of starting material suitable for metabarcoding studies.

    PubMed

    Taberlet, Pierre; Prud'Homme, Sophie M; Campione, Etienne; Roy, Julien; Miquel, Christian; Shehzad, Wasim; Gielly, Ludovic; Rioux, Delphine; Choler, Philippe; Clément, Jean-Christophe; Melodelima, Christelle; Pompanon, François; Coissac, Eric

    2012-04-01

    DNA metabarcoding refers to the DNA-based identification of multiple species from a single complex and degraded environmental sample. We developed new sampling and extraction protocols suitable for DNA metabarcoding analyses targeting soil extracellular DNA. The proposed sampling protocol has been designed to reduce, as much as possible, the influence of local heterogeneity by processing a large amount of soil resulting from the mixing of many different cores. The DNA extraction is based on the use of saturated phosphate buffer. The sampling and extraction protocols were validated first by analysing plant DNA from a set of 12 plots corresponding to four plant communities in alpine meadows, and, second, by conducting pilot experiments on fungi and earthworms. The results of the validation experiments clearly demonstrated that sound biological information can be retrieved when following these sampling and extraction procedures. Such a protocol can be implemented at any time of the year without any preliminary knowledge of specific types of organisms during the sampling. It offers the opportunity to analyse all groups of organisms using a single sampling/extraction procedure and opens the possibility to fully standardize biodiversity surveys.

  12. [A large amount of distilled water ineffective for prevention of bladder cancer cell implantation at the time of transurethral resection].

    PubMed

    Sakai, Yasuyuki; Fujii, Yasuhisa; Hyochi, Nobuhiko; Masuda, Hitoshi; Kawakami, Satoru; Kobayashi, Tsuyoshi; Kageyama, Yukio; Kihara, Kazunori

    2006-03-01

    A previous study indicated that distilled water could prevent bladder tumor cell implantation in an in vitro assay. We investigated whether a large amount of distilled water irrigation prevented recurrence of superficial bladder cancer in the clinical setting and then we estimated whether cancer cell implantation at the time of transurethral resection is a major mechanism of recurrence. Between May 2000 and January 2002, 22 patients with primary, superficial bladder carcinoma who underwent transurethral resection of bladder tumors (TURBT) were enrolled in this study. The patients underwent bladder washout with 1,000 ml distilled water immediately after TURBT, and then intravesical irrigation with 3,000 ml water for three hours. Control patients were randomly chosen from those who previously underwent TURBT in our hospital and had similar prognostic factors. The 1- and 2-year recurrence-free rates in the patients undergoing distilled water irrigation were both 45% and those in the control patients were 65% and 45%, respectively. There were no significant differences between the two groups. This result indicates that distilled water was ineffective in preventing recurrence of superficial bladder tumor. PMID:16617868

  13. Effects of interactive transport and scavenging of smoke on the calculated temperature change resulting from large amounts of smoke

    SciTech Connect

    MacCracken, M.C.; Walton, J.J.

    1984-12-01

    Several theoretical studies with numerical models have shown that substantial land-surface cooling can occur if very large amounts (approx. 100 x 10/sup 12/ = 100 Tg) of highly absorbing sooty-particles are injected high into the troposphere and spread instantaneously around the hemisphere (Turco et al., 1983; Covey et al. 1984; MacCracken, 1983). A preliminary step beyond these initial calculations has been made by interactively coupling the two-layer, three-dimensional Oregon State University general circulation model (GCM) to the three-dimensional GRANTOUR trace species model developed at the Lawrence Livermore National Laboratory. The GCM simulation includes treatment of tropospheric dynamics and thermodynamics and the effect of soot on solar radiation. The GRANTOUR simulation includes treatment of particle transport and scavenging by precipitation, although no satisfactory verification of the scavenging algorithm has yet been possible. We have considered the climatic effects of 150 Tg (i.e., the 100 Mt urban war scenario from Turco et al., 1983) and of 15 Tg of smoke from urban fires over North America and Eurasia. Starting with a perpetual July atmospheric situation, calculation of the climatic effects as 150 Tg of smoke are spread slowly by the winds, rather than instantaneously dispersed as in previous calculations, leads to some regions of greater cooling under the denser parts of the smoke plumes and some regions of less severe cooling where smoke arrival is delayed. As for the previous calculations, mid-latitude decreases of land surface air temperature for the 150 Tg injection are greater than 15/sup 0/C after a few weeks. For a 15 Tg injection, however, cooling of more than several degrees centigrade only occurs in limited regions under the dense smoke plumes present in the first few weeks after the injection. 10 references, 9 figures.

  14. SN 2010mb: Direct evidence for a supernova interacting with a large amount of hydrogen-free circumstellar material

    SciTech Connect

    Ben-Ami, Sagi; Gal-Yam, Avishay; Rabinak, Itay; Yaron, Ofer; Arcavi, Iair; Ofek, Eran O.; Mazzali, Paolo A.; Gnat, Orly; Modjaz, Maryam; Sullivan, Mark; Bildsten, Lars; Poznanski, Dovi; Bloom, Joshua S.; Nugent, Peter E.; Horesh, Assaf; Kulkarni, Shrinivas R.; Perley, Daniel; Kasliwal, Mansi M.; Quimby, Robert; Xu, Dong

    2014-04-10

    We present our observations of SN 2010mb, a Type Ic supernova (SN) lacking spectroscopic signatures of H and He. SN 2010mb has a slowly declining light curve (LC) (∼600 days) that cannot be powered by {sup 56}Ni/{sup 56}Co radioactivity, the common energy source for Type Ic SNe. We detect signatures of interaction with hydrogen-free circumstellar material including a blue quasi-continuum and, uniquely, narrow oxygen emission lines that require high densities (∼10{sup 9} cm{sup –3}). From the observed spectra and LC, we estimate that the amount of material involved in the interaction was ∼3 M {sub ☉}. Our observations are in agreement with models of pulsational pair-instability SNe described in the literature.

  15. Increased Mortality of Respiratory Diseases, Including Lung Cancer, in the Area with Large Amount of Ashfall from Mount Sakurajima Volcano

    PubMed Central

    Higuchi, Kenta; Koriyama, Chihaya; Akiba, Suminori

    2012-01-01

    Objectives. Mount Sakurajima in Japan is one of the most active volcanoes in the world. This work was conducted to examine the effect of volcanic ash on the chronic respiratory disease mortality in the vicinity of Mt. Sakurajima. Methods. The present work examined the standardized mortality ratios (SMRs) of respiratory diseases during the period 1968–2002 in Sakurajima town and Tarumizu city, where ashfall from the volcano recorded more than 10.000 g/m2/yr on average in the 1980s. Results. The SMR of lung cancer in the Sakurajima-Tarumizu area was 1.61 (95% CI = 1.44–1.78) for men and 1.67 (95% CI = 1.39–1.95) for women while it was nearly equal to one in Kanoya city, which neighbors Tarumizu city but located at the further position from Mt. Sakurajima, and therefore has much smaller amounts of ashfall. Sakurajima-Tarumizu area had elevated SMRs for COPDs and acute respiratory diseases while Kanoya did not. Conclusions. Cristobalite is the most likely cause of the increased deaths from those chronic respiratory diseases since smoking is unlikely to explain the increased mortality of respiratory diseases among women since the proportion of smokers in Japanese women is less than 20%, and SPM levels in the Sakurajima-Tarumizu area were not high. Further studies seem warranted. PMID:22536275

  16. Draft Genome Sequence of Agreia bicolorata Strain AC-1804, a Producer of Large Amounts of Carotenoid Pigments, Isolated from Narrow Reed Grass Infected by the Phytoparasitic Nematode

    PubMed Central

    Siniagina, Maria; Malanin, Sergey; Boulygina, Eugenia; Grygoryeva, Tatiana; Yarullina, Dina; Ilinskaya, Olga

    2015-01-01

    Here, we report the draft genome sequence of Agreia bicolorata strain AC-1804, isolated from narrow reed grass galls induced by a plant-parasitic nematode which is able to produce large amounts of carotenoid pigments. The draft genome sequence of 3,919,485 bp provides a resource for carotenoid pathway research. PMID:26634752

  17. Monitoring feed amounts in goliath groupers (Epinephelus itajara) using behavioral conditioning in a large mixed species exhibit.

    PubMed

    Kittell, Michele M; Ratte, Magan E

    2008-09-01

    Goliath groupers (Epinephelus itajara) are large charismatic species, which are often residents in public aquaria. This study reports a novel approach to feeding techniques for three resident goliath groupers. Because of the size and depth of their exhibit, the groupers were conditioned to hand feed from aquarists. Daily food logs were recorded including the type and number of species, how often the groupers were fed, and how often they accepted the offered food. Mackerel, herring, and sardine represented the highest percentage of the diet, whereas capelin, squid, and shrimp were the lowest percentage. Over a one-year period, records showed that grouper 1 and grouper 3 ate fairly consistently throughout the year. Grouper 2 had a higher degree of variation in his monthly feeding average with a decrease from May to September and an increase through April. Grouper 1 and grouper 3 took food from the aquarists most consistently with a monthly average of 88.8+/-10.8 and 89.7+/-6.15% of the time, respectively. Grouper 2 was not as consistent, hand feeding at only 74.5+/-16.2% of the time offered. Diet management and behavioral conditioning with the goliath groupers have established consistent husbandry records and therefore better monitoring of the individual fish's long-term health status. Zoo Biol 27:414-419, 2008. (c) 2008 Wiley-Liss, Inc.

  18. Monitoring feed amounts in goliath groupers (Epinephelus itajara) using behavioral conditioning in a large mixed species exhibit.

    PubMed

    Kittell, Michele M; Ratte, Magan E

    2008-09-01

    Goliath groupers (Epinephelus itajara) are large charismatic species, which are often residents in public aquaria. This study reports a novel approach to feeding techniques for three resident goliath groupers. Because of the size and depth of their exhibit, the groupers were conditioned to hand feed from aquarists. Daily food logs were recorded including the type and number of species, how often the groupers were fed, and how often they accepted the offered food. Mackerel, herring, and sardine represented the highest percentage of the diet, whereas capelin, squid, and shrimp were the lowest percentage. Over a one-year period, records showed that grouper 1 and grouper 3 ate fairly consistently throughout the year. Grouper 2 had a higher degree of variation in his monthly feeding average with a decrease from May to September and an increase through April. Grouper 1 and grouper 3 took food from the aquarists most consistently with a monthly average of 88.8+/-10.8 and 89.7+/-6.15% of the time, respectively. Grouper 2 was not as consistent, hand feeding at only 74.5+/-16.2% of the time offered. Diet management and behavioral conditioning with the goliath groupers have established consistent husbandry records and therefore better monitoring of the individual fish's long-term health status. Zoo Biol 27:414-419, 2008. (c) 2008 Wiley-Liss, Inc. PMID:19360635

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

    NASA Astrophysics Data System (ADS)

    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.

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

    PubMed

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

    2014-01-01

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

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

    PubMed

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

    2014-01-01

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

  2. Primary, secondary, and tertiary amines for CO2 capture: designing for mesoporous CO2 adsorbents.

    PubMed

    Ko, Young Gun; Shin, Seung Su; Choi, Ung Su

    2011-09-15

    CO(2) emissions, from fossil-fuel-burning power plants, the breathing, etc., influence the global worming on large scale and the man's work efficiency on small scale. The reversible capture of CO(2) is a prominent feature of CO(2) organic-inorganic hybrid adsorbent to sequester CO(2). Herein, (3-aminopropyl) trimethoxysilane (APTMS), [3-(methylamino)propyl] trimethoxysilane (MAPTMS), and [3-(diethylamino) propyl] trimethoxysilane (DEAPTMS) are immobilized on highly ordered mesoporous silicas (SBA-15) to catch CO(2) as primary, secondary, and tertiary aminosilica adsorbents. X-ray photoelectron spectroscopy was used to analyze the immobilized APTMS, MAPTMS, and DEAPTMS on the SBA-15. We report an interesting discovery that the CO(2) adsorption and desorption on the adsorbent depend on the amine type of the aminosilica adsorbent. The adsorbed CO(2) was easily desorbed from the adsorbent with the low energy consumption in the order of tertiary, secondary, and primary amino-adsorbents while the adsorption amount and the bonding-affinity increased in the reverse order. The effectiveness of amino-functionalized (1(o), 2(o), and 3(o) amines) SBA-15s as a CO(2) capturing agent was investigated in terms of adsorption capacity, adsorption-desorption kinetics, and thermodynamics. This work demonstrates apt amine types to catch CO(2) and regenerate the adsorbent, which may open new avenues to designing "CO(2) basket". PMID:21708387

  3. Adsorbed natural gas storage with activated carbon

    SciTech Connect

    Sun, Jian; Brady, T.A.; Rood, M.J.

    1996-12-31

    Despite technical advances to reduce air pollution emissions, motor vehicles still account for 30 to 70% emissions of all urban air pollutants. The Clean Air Act Amendments of 1990 require 100 cities in the United States to reduce the amount of their smog within 5 to 15 years. Hence, auto emissions, the major cause of smog, must be reduced 30 to 60% by 1998. Natural gas con be combusted with less pollutant emissions. Adsorbed natural gas (ANG) uses adsorbents and operates with a low storage pressure which results in lower capital costs and maintenance. This paper describes the production of an activated carbon adsorbent produced from an Illinois coal for ANG.

  4. Modeling adsorption: Investigating adsorbate and adsorbent properties

    NASA Astrophysics Data System (ADS)

    Webster, Charles Edwin

    1999-12-01

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

  5. Separation of traces and large amounts of lead from gram amounts of bismuth, tin, cadmium, and indium by cation exchange chromatography in hydrochloric acid - methanol using a macroporous resin

    SciTech Connect

    Strelow, F.W.E.

    1985-10-01

    Traces and small amounts of lead can be separated from gram amounts of Bi, Sn, Cd, and In by eluting these elements with 0.5 M HCl in 50% methanol from a column containing only 2.7 mL (1g) of Bio-Rad AG MP-50 macroporous cation exchange resin of 100-200 mesh particle size in the H form. A 5.4 mL (2 g) resin column separates up to 100 mg of lead. Lead can be eluted effectively with 3.0 M aqueous HCl. Separations are sharp and quantitative. In combination with flame atomic absorption spectrometry, the method has been applied for the determination of lead in pure metals or chemicals of the above elements. Relative standard deviations were better than 1% for samples containing 10 ppm of lead or more. The sensitivity is less than 0.1 ppm. Relevant elution curves and results of analyses of binary synthetic mixtures and actual samples are presented. 7 references, 4 figures, 2 tables.

  6. Molecular Adsorber Coating

    NASA Technical Reports Server (NTRS)

    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.

  7. Using specialized adsorbents for remediation

    SciTech Connect

    Hochmuth, D.P.; Grant, A.

    1995-11-01

    This paper describes two remediation case studies in which specialized adsorbents were used. In one case, the adsorbents were used to treat effluent from a soil vapor extraction system. In the other case, the adsorbents were used to treat air from a groundwater air stripper. The specialized adsorbents effectively removed volatile organic compounds from each air stream.

  8. Where will large amounts of materials accumulated within the economy go?--A material flow analysis of construction minerals for Japan.

    PubMed

    Hashimoto, Seiji; Tanikawa, Hiroki; Moriguchi, Yuichi

    2007-01-01

    For all countries analyzed so far, Material Flow Analysis/Accounting (MFA) studies indicate that the overall stock of materials within the economy is growing. Most are construction minerals such as asphalt, cement, sand and gravel, crushed stone, and other aggregates. In the analyses described in this paper, flows and stocks of construction minerals were estimated for Japan from the past to the future to elucidate: (1) the mechanisms by which construction minerals become waste, and (2) the future supply of and demand for recycled crushed stone. The following conclusions were drawn: (1) The amounts of waste construction minerals generated have been and will be at much lower levels than the domestic demand for construction minerals. These differences might indicate consistent growth of the stock of construction minerals, which will become waste in the future. However, certain amounts of materials that we account for as stock can be interpreted already in the environment as dead stock or dissipated waste; such materials can be called "missing stock" or "dissipated stock". Capturing that missing or dissipated stock is very important because it provides information that clarifies the environmental impacts and loss of resources that these materials cause; it allows estimation of appropriate future waste generation. (2) The amount of construction minerals that are recognized as waste was estimated to increase in the future. An imbalance in the supply of and demand for recycled crushed stone will likely occur in the near future if an expected decline in future road construction is considered.

  9. Novel adsorbent applicability for decontamination of printing wastewater

    NASA Astrophysics Data System (ADS)

    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 < B = pure C < C with PEG 600 addition. The adsorption equilibrium data of Zn(II) ion on NZ, B, pure C and C with PEG 600 were analyzed in terms of the Freundlich, Langmuir and Dubinin-Kaganer-Radushkevich (DKR) isotherm models. The characteristic parameters for each isotherms and related correlation coefficients were determined. The values of correlation coefficient (R2) indicated the following order of the isotherm models: Freundlich > Langmuir > DKR. The study also showed that the fired clay modified with PEG 600 addition has great potential

  10. Atomic absorption spectrophotometric determination of microgram levels of Co, Ni, Cu, Pb, and Zn in soil and sediment extracts containing large amounts of Mn and Fe

    USGS Publications Warehouse

    Chao, T.T.; Sanzolone, R.F.

    1973-01-01

    An atomic absorption spectrophotometric method has been developed for the determination of seven metal ions in the hydroxylamine extract of soils and sediments. Mn, Fe, and Zn are directly determined in the aqueous extract upon dilution. Co, Ni, Cu, and Pb in a separate aliquot of the extract are chelated with APDC (ammonium pyrrolidine dithiocarbamate) and extracted into MIBK (methyl isobutyl ketone) before determination. Data are presented to show the quantitative recovery of microgram levels of Co, Ni, Cu, and Pb by APDC-MIBK chelation-extraction from synthetic solutions containing as much as 2,000 ug/ml (micrograms per milliliter) Mn or 50 ug/ml Fe. Recovery of known amounts of the metal ions from sample solutions is equally satisfactory. Reproducible results are obtained by replicate analyses of two sediment samples for the seven metals.

  11. Method for quantitative determination and separation of trace amounts of chemical elements in the presence of large quantities of other elements having the same atomic mass

    DOEpatents

    Miller, C.M.; Nogar, N.S.

    1982-09-02

    Photoionization via autoionizing atomic levels combined with conventional mass spectroscopy provides a technique for quantitative analysis of trace quantities of chemical elements in the presence of much larger amounts of other elements with substantially the same atomic mass. Ytterbium samples smaller than 10 ng have been detected using an ArF* excimer laser which provides the atomic ions for a time-of-flight mass spectrometer. Elemental selectivity of greater than 5:1 with respect to lutetium impurity has been obtained. Autoionization via a single photon process permits greater photon utilization efficiency because of its greater absorption cross section than bound-free transitions, while maintaining sufficient spectroscopic structure to allow significant photoionization selectivity between different atomic species. Separation of atomic species from others of substantially the same atomic mass is also described.

  12. Adsorbent and adsorbent bed for materials capture and separation processes

    SciTech Connect

    Liu, Wei

    2011-01-25

    A method device and material for performing adsorption wherein a fluid mixture is passed through a channel in a structured adsorbent bed having a solid adsorbent comprised of adsorbent particles having a general diameter less than 100 um, loaded in a porous support matrix defining at least one straight flow channel. The adsorbent bed is configured to allow passage of a fluid through said channel and diffusion of a target material into said adsorbent under a pressure gradient driving force. The targeted molecular species in the fluid mixture diffuses across the porous support retaining layer, contacts the adsorbent, and adsorbs on the adsorbent, while the remaining species in the fluid mixture flows out of the channel.

  13. Recombinant MUC1 mucin with a breast cancer-like O-glycosylation produced in large amounts in Chinese-hamster ovary cells.

    PubMed Central

    Bäckström, Malin; Link, Thomas; Olson, Fredrik J; Karlsson, Hasse; Graham, Rosalind; Picco, Gianfranco; Burchell, Joy; Taylor-Papadimitriou, Joyce; Noll, Thomas; Hansson, Gunnar C

    2003-01-01

    We have developed an expression system for the production of large quantities of recombinant MUC1 mucin in CHO-K1 (Chinese-hamster ovary K1) cells. The extracellular part of human MUC1, including 16 MUC1 tandem repeats, was produced as a fusion protein with murine IgG Fc, with an intervening enterokinase cleavage site for the removal of the Fc tail. Stable MUC1-IgG-producing CHO-K1 clones were generated and were found to secrete MUC1-IgG into the culture medium. After adaptation to suspension culture in protein-free medium in a bioreactor, the fusion protein was secreted in large quantities (100 mg/l per day) into the culture supernatant. From there, MUC1 could be purified to homogeneity using a two-step procedure including enterokinase cleavage and ion-exchange chromatography. Capillary liquid chromatography MS of released oligosaccharides from CHO-K1-produced MUC1 identified the main O-glycans as Galbeta1-3GalNAc (core 1) and mono- and di-sialylated core 1. The glycans occupied on average 4.3 of the five potential O-glycosylation sites in the tandem repeats, as determined by nano-liquid chromatography MS of partially deglycosylated Clostripain-digested protein. A very similar O-glycan profile and site occupancy was found in MUC1-IgG produced in the breast carcinoma cell line T47D, which has O-glycosylation typical for breast cancer. In contrast, MUC1-IgG produced in another breast cancer cell line, MCF-7, showed a more complex pattern with both core 1- and core 2-based O-glycans. This is the first reported production of large quantities of recombinant MUC1 with a breast cancer-like O-glycosylation that could be used for the immunotherapy of breast cancer. PMID:12950230

  14. Kaempferia parviflora, a plant used in traditional medicine to enhance sexual performance contains large amounts of low affinity PDE5 inhibitors

    PubMed Central

    Temkitthawon, Prapapan; Hinds, Thomas R.; Beavo, Joseph A.; Viyoch, Jarupa; Suwanborirux, Khanit; Pongamornkul, Wittaya; Sawasdee, Pattara; Ingkaninan, Kornkanok

    2014-01-01

    Aim of the study A number of medicinal plants are used in traditional medicine to treat erectile dysfunction. Since cyclic nucleotide PDEs inhibitors underlie several current treatments for this condition, we sought to show whether these plants might contain substantial amounts of PDE5 inhibitors. Materials and methods Forty one plant extracts and eight 7-methoxyflavones from Kaempferia parviflora Wall. ex Baker were screened for PDE5 and PDE6 inhibitory activities using the two-step radioactive assay. The PDE5 and PDE6 were prepared from mice lung and chicken retinas, respectively. All plant extracts were tested at 50 μg/ml whereas the pure compounds were tested at 10 μM. Results From forty one plant extracts tested, four showed the PDE5 inhibitory effect. The chemical constituents isolated from rhizomes of Kaempferia parviflora were further investigated on inhibitory activity against PDE5 and PDE6. The results showed that 7-methoxyflavones from this plant showed inhibition toward both enzymes. The most potent PDE5 inhibitor was 5,7-dimethoxyflavone (IC50 = 10.64 ± 2.09 μM, selectivity on PDE5 over PDE6 = 3.71). Structure activity relationship showed that the methoxyl group at C-5 position of 7-methoxyflavones was necessary for PDE5 inhibition. Conclusions Kaempferia parviflora rhizome extract and its 7-methoxyflavone constituents had moderate inhibitory activity against PDE5. This finding provides an explanation for enhancing sexual performance in the traditional use of Kaempferia parviflora. Moreover, 5,7-dimethoxyflavones should make a useful lead compound to further develop clinically efficacious PDE5 inhibitors. PMID:21884777

  15. From adsorption to condensation: the role of adsorbed molecular clusters.

    PubMed

    Yaghoubian, Sima; Zandavi, Seyed Hadi; Ward, C A

    2016-08-01

    The adsorption of heptane vapour on a smooth silicon substrate with a lower temperature than the vapour is examined analytically and experimentally. An expression for the amount adsorbed under steady state conditions is derived from the molecular cluster model of the adsorbate that is similar to the one used to derive the equilibrium Zeta adsorption isotherm. The amount adsorbed in each of a series of steady experiments is measured using a UV-vis interferometer, and gives strong support to the amount predicted to be adsorbed. The cluster distribution is used to predict the subcooling temperature required for the adsorbed vapour to make a disorder-order phase transition to become an adsorbed liquid, and the subcooling temperature is found to be 2.7 ± 0.4 K. The continuum approach for predicting the thickness of the adsorbed liquid film originally developed by Nusselt is compared with that measured and is found to over-predict the thickness by three-orders of magnitude. PMID:27426944

  16. [Melting in adsorbed films

    SciTech Connect

    Simon, M.I.

    1992-01-01

    Over the past several years we have been developing a new approach to cloning large fragments of mammalian DNA in E. coli. which will permit detailed analysis of complex genomes. In January 1992 we began construction of an arrayed total human genomic library prepared in our BAC vector. Our goal is to create a 4-5X library which will be accessible for screening both by colony hybridization and by PCR. Our efforts in 1992 have been focused on expanding this library, characterizing specific clones isolated from the library, and demonstrating the use of BACs and Fosmids in creating physical maps. As a Model for the use of BACs in physical mapping, we have begun mapping human chromosome 22. In addition to their stability and ease of handling, BACs and Fosniids offer the advantage of permitting isolation of relatively large amounts of pure DNA which should greatly facilitate contig construction. We have created a 7X chromosome 22-specific Fosmid library consisting of clones obtained from DNA from a hybrid cell line.

  17. Surface properties of mesoporous carbon-silica gel adsorbents

    SciTech Connect

    Leboda, R.; Turov, V.V.; Charmas, B.; Skubiszewska-Zieba, J.; Gun'ko, V.M.

    2000-03-01

    Carbon/silica (carbosil) samples prepared utilizing mesoporous silica gel (Si-60) modified by methylene chloride pyrolysis were studied by nitrogen adsorption, quasi-isothermal thermogravimetry, p-nitrophenol adsorption from aqueous solution, and {sup 1}H NMR methods. The structural characteristics and other properties of carbosils depend markedly on the synthetic conditions and the amount of carbon deposited. The changes in the pore size distribution with increasing carbon concentration suggest grafting of carbon mainly in pores, leading to diminution of the mesopore radii. However, heating pure silica gel at the pyrolysis temperature of 550 C leads to an increase in the pore radii. The quasi-isothermal thermogravimetry and {sup 1}H NMR spectroscopy methods used to investigate the water layers on carbosils showed a significant capability of carbosils to adsorb water despite a relatively large content of the hydrophobic carbon deposit, which represents a nonuniform layer incompletely covering the oxide surface.

  18. Nitrogen-rich porous adsorbents for CO2 capture and storage.

    PubMed

    Li, Pei-Zhou; Zhao, Yanli

    2013-08-01

    The construction of physical or chemical adsorbents for CO2 capture and sequestration (CCS) is a vital technology in the interim period on the way towards a sustainable low-carbon future. The search for efficient materials to satisfy the increasing demand for CCS has become extremely important. Porous materials, including porous silica, porous carbons, and newly developed metal-organic frameworks and porous organic polymers, possessing regular and well-defined porous geometry and having a high surface area and pore volume, have been widely studied for separations on laboratory scale. On account of the dipole-quadrupole interactions between the polarizable CO2 molecule and the accessible nitrogen site, the investigations have indicated that the incorporation of accessible nitrogen-donor groups into the pore walls of porous materials can improve the affinity to CO2 and increase the CO2 uptake capacity and selectivity. The CO2 -adsorption process based on solid nitrogen-rich porous adsorbents does generally not require heating of a large amount of water (60-70 wt%) for regeneration, while such a heating approach cannot be avoided in the regeneration of amine-based solution absorption processes. Thus, nitrogen-rich porous adsorbents show good regeneration properties without sacrificing high separation efficiency. As such, nitrogen-rich porous materials as highly promising CO2 adsorbents have been broadly fabricated and intensively investigated. This Focus Review highlights recent significant advances in nitrogen-rich porous materials for CCS.

  19. Activity of lactoperoxidase when adsorbed on protein layers.

    PubMed

    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. Graphene protected surface state on Ir(111) with adsorbed lithium

    NASA Astrophysics Data System (ADS)

    Lazic, Predrag; Pervan, Petar; Petrovic, Marin; Srut-Rakic, Iva; Pletikosic, Ivo; Kralj, Marko; Milun, Milorad; Valla, Tonica

    It is well known that electronic surface states (SS) get strongly perturbed upon the chemical adsorption of very small amount of adsorbates. Adsorption of lithium atoms on Ir(111) is no exception to that rule. Iridium SS gets strongly perturbed and is practically eradicated - it can not be seen as a sharp peak in the ARPES measurement. However, if the system is prepared with graphene on top of Ir/Li system, the iridium SS reappears. We present a combined experimental and theoretical study of the described system. Using the density functional theory calculations for large unit cells with disordered lithium atoms geometries on the (111) surface of iridium we were able to reproduce the results of the ARPES measurements - showing clearly that the SS signal is strongly suppressed when lithium is adsorbed, while it is almost unchanged when lithium is intercalated (i.e. with graphene on top of it). Looking at the projected density of states we constructed a rather simple model explaining this behavior which seems to be general.

  1. Magnesium silicates adsorbents of organic compounds

    NASA Astrophysics Data System (ADS)

    Ciesielczyk, Filip; Krysztafkiewicz, Andrzej; Jesionowski, Teofil

    2007-08-01

    Studies were presented on production of highly dispersed magnesium silicate at a pilote scale. The process of silicate adsorbent production involved precipitation reaction using water glass (sodium metasilicate) solution and appropriate magnesium salt, preceded by an appropriate optimization stage. Samples of best physicochemical parameters were in addition modified (in order to introduce to silica surface of several functional groups) using the dry technique and various amounts of 3-isocyanatepropyltrimethoxysilane, 3-thiocyanatepropyltrimethoxysilane, N-phenyl-3-aminopropyltrimethoxysilane. The so prepared samples were subjected to a comprehensive physicochemical analysis. At the terminal stage of studies attempts were made to adsorb phenol from its aqueous solutions on the surface of unmodified and modified magnesium silicates. Particle size distributions were determined using the ZetaSizer Nano ZS apparatus. In order to define adsorptive properties of studied magnesium silicates isotherms of nitrogen adsorption/desorption on their surfaces were established. Efficiency of phenol adsorption was tested employing analysis of post-adsorption solution.

  2. Semi-quantitative Measure of Fluid Amount and Distribution in and Around the Fault Zone During and After a Large Seismic Slip, an Example From Kamishiro-Fault During 2014 North Nagano Earthquake

    NASA Astrophysics Data System (ADS)

    Tanaka, H.; Ma, K. F.

    2015-12-01

    Exploring the relationship between mode of seismicity and distribution and amount fluids in and around the fault zone is one of the most important issues to understand the mechanism of earthquake generation. However, quantitative measure of amount and distribution of the fluids has been difficult target to estimate so far. We tried to overcome this barrier by using transient discharge of hot-spring fluids associated with a large earthquake. On November 22, 2014 at 22:08, a large earthquake (M 6.7 depth 5.0 km) occurred at the Hakuba area, Northern part of Nagano Prefecture (Naganoken-Hokubu Earthquake). The Kamishiro Fault, striking NS and dipping moderately to the east, and one of the active traces of Itoigawa-Shizuoka Tectonic Line, was activated by the earthquake, and generated the surface displacements (reverse + left lateral, less than 0.5m) mainly at the southern trace of the fault. Eight hours after the main shock, hot spring suddenly gushed out at the northern part of Kamishiro Fault. We kept measuring the flow amount, electric conductivity, pH, chemical- and isotopic- characteristics of the spring-fluids for four months until transient spring was dried out. A clear trend of exponential decay of flow amount was observed (R2 = 8.63) with time, and total volume of fluid sprang out is estimated to be 7300 m3. Using our fluid - porous fracture zone model and Darcy-Brinkman's equation, we estimated fluid pressure right after the main shock at the focal depth. Based on the results of observation and calculation, we discuss the relationship between mode of seismicity and fluid condition in and around the activated fault zone.

  3. Mercury adsorption properties of sulfur-impregnated adsorbents

    USGS Publications Warehouse

    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.

  4. Nanoclay-Based Solid-Amine Adsorbents for Carbon Dioxide Capture

    NASA Astrophysics Data System (ADS)

    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

  5. Analysis of Adsorbed Natural Gas Tank Technology

    NASA Astrophysics Data System (ADS)

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

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

  6. A rapid and practical strategy for the determination of platinum, palladium, ruthenium, rhodium, iridium and gold in large amounts of ultrabasic rock by inductively coupled plasma optical emission spectrometry combined with ultrasound extraction

    NASA Astrophysics Data System (ADS)

    Zhang, Gai; Tian, Min

    2015-04-01

    This proposed method regulated the determination of platinum, palladium, ruthenium, rhodium, iridium and gold in platinum-group ores by nickel sulfide fire assay—inductively coupled plasma optical emission spectrometry (ICP-OES) combined with ultrasound extraction for the first time. The quantitative limits were 0.013-0.023μg/g. The samples were fused to separate the platinum-group elements from matrix. The nickel sulfide button was then dissolved with hydrochloric acid and the insoluble platinum-group sulfide residue was dissolved with aqua regia by ultrasound bath and finally determined by ICP-OES. The proposed method has been applied into the determination of platinum-group element and gold in large amounts of ultrabasic rocks from the Great Dyke of Zimbabwe.

  7. The entropies of adsorbed molecules.

    PubMed

    Campbell, Charles T; Sellers, Jason R V

    2012-10-31

    Adsorbed molecules are involved in many reactions on solid surface that are of great technological importance. As such, there has been tremendous effort worldwide to learn how to predict reaction rates and equilibrium constants for reactions involving adsorbed molecules. Theoretical calculation of both the rate and equilibrium constants for such reactions requires knowing the entropy and enthalpy of the adsorbed molecule. While much effort has been devoted to measuring and calculating the enthalpies of well-defined adsorbates, few measurements of the entropies of adsorbates have been reported. We present here a new way to determine the standard entropies of adsorbed molecules (S(ad)(0)) on single crystal surfaces from temperature programmed desorption data, prove its accuracy by comparison to entropies measured by equilibrium methods, and apply it to published data to extract new entropies. Most importantly, when combined with reported entropies, we find that at high coverage, they linearly track the entropy of the gas-phase molecule at the same temperature (T), such that S(ad)(0)(T) = 0.70 S(gas)(0)(T) - 3.3R (R = the gas constant), with a standard deviation of only 2R over a range of 50R. These entropies, which are ~2/3 of the gas, are huge compared to most theoretical predictions. This result can be extended to reliably predict prefactors in the Arrhenius rate constant for surface reactions involving such species, as proven here for desorption. PMID:23033909

  8. Cryogenic adsorber design in a helium refrigeration system

    NASA Astrophysics Data System (ADS)

    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.

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

    NASA Astrophysics Data System (ADS)

    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.

  10. Effective Thermal Conductivity of Adsorbent Packed Beds

    NASA Astrophysics Data System (ADS)

    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.

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

    SciTech Connect

    Weinelt, M.; Nilsson, A.; Wassdahl, N.

    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.

  12. Waste water treatment for heavy metal toxins using plant and hair as adsorbents.

    PubMed

    Krishnan, S S; Cancilla, A; Jervis, R E

    1988-01-01

    The adsorption of cadmium, mercury and lead by Cattails (Typha Plant) and human hair has been investigated to assess their possible use as adsorbents in the treatment of industrial wastewater. Capacity experiments were performed, and it was found that significant amounts of cadmium, mercury and lead were adsorbed by Cattails, while only mercury was adsorbed by hair. Depending upon the concentration, adsorption capacities varied from 1 to 27 mg of metal per gram of adsorbent. The relatively fast uptake of cadmium and lead by Cattail leaves suggests that a continuous process is viable. The results are similar in the case of hair and mercury.

  13. Rotary adsorbers for continuous bulk separations

    DOEpatents

    Baker, Frederick S.

    2011-11-08

    A rotary adsorber for continuous bulk separations is disclosed. The rotary adsorber includes an adsorption zone in fluid communication with an influent adsorption fluid stream, and a desorption zone in fluid communication with a desorption fluid stream. The fluid streams may be gas streams or liquid streams. The rotary adsorber includes one or more adsorption blocks including adsorbent structure(s). The adsorbent structure adsorbs the target species that is to be separated from the influent fluid stream. The apparatus includes a rotary wheel for moving each adsorption block through the adsorption zone and the desorption zone. A desorption circuit passes an electrical current through the adsorbent structure in the desorption zone to desorb the species from the adsorbent structure. The adsorbent structure may include porous activated carbon fibers aligned with their longitudinal axis essentially parallel to the flow direction of the desorption fluid stream. The adsorbent structure may be an inherently electrically-conductive honeycomb structure.

  14. Uranium Adsorbent Fibers Prepared by Atom-Transfer Radical Polymerization from Chlorinated Polypropylene and Polyethylene Trunk Fibers

    SciTech Connect

    Brown, Suree; Chatterjee, Sabornie; Li, Meijun; Yue, Yanfeng; Tsouris, Costas; Janke, Christopher J.; Saito, Tomonori; Dai, Sheng

    2015-12-10

    Seawater contains a large amount of uranium (~4.5 billion tons) which can serve as a limitless supply of an energy source. However, in order to make the recovery of uranium from seawater economically feasible, lower manufacturing and deployment costs are required, and thus, solid adsorbents must have high uranium uptake, reusability, and high selectivity toward uranium. In this study, atom-transfer radical polymerization (ATRP), without the radiation-induced graft polymerization (RIGP), was used for grafting acrylonitrile (AN) and tert-butyl acrylate (tBA) from a new class of trunk fibers, forming adsorbents in a readily deployable form. The new class of trunk fibers was prepared by the chlorination of PP round fiber, hollow-gear-shaped PP fiber, and hollow-gear-shaped PE fiber. During ATRP, degrees of grafting (d.g.) varied according to the structure of active chlorine sites on trunk fibers and ATRP conditions, and the d.g. as high as 2570% was obtained. Resulting adsorbent fibers were evaluated in U-spiked simulated seawater and the maximum adsorption capacity of 146.6 g U/kg, much higher than that of a standard adsorbent JAEA fiber (75.1 g/kg), was obtained. This new type of trunk fibers can be used for grafting a variety of uranium-interacting ligands, including designed ligands that are highly selective toward uranium.

  15. Uranium Adsorbent Fibers Prepared by Atom-Transfer Radical Polymerization from Chlorinated Polypropylene and Polyethylene Trunk Fibers

    DOE PAGES

    Brown, Suree; Chatterjee, Sabornie; Li, Meijun; Yue, Yanfeng; Tsouris, Costas; Janke, Christopher J.; Saito, Tomonori; Dai, Sheng

    2015-12-10

    Seawater contains a large amount of uranium (~4.5 billion tons) which can serve as a limitless supply of an energy source. However, in order to make the recovery of uranium from seawater economically feasible, lower manufacturing and deployment costs are required, and thus, solid adsorbents must have high uranium uptake, reusability, and high selectivity toward uranium. In this study, atom-transfer radical polymerization (ATRP), without the radiation-induced graft polymerization (RIGP), was used for grafting acrylonitrile (AN) and tert-butyl acrylate (tBA) from a new class of trunk fibers, forming adsorbents in a readily deployable form. The new class of trunk fibers wasmore » prepared by the chlorination of PP round fiber, hollow-gear-shaped PP fiber, and hollow-gear-shaped PE fiber. During ATRP, degrees of grafting (d.g.) varied according to the structure of active chlorine sites on trunk fibers and ATRP conditions, and the d.g. as high as 2570% was obtained. Resulting adsorbent fibers were evaluated in U-spiked simulated seawater and the maximum adsorption capacity of 146.6 g U/kg, much higher than that of a standard adsorbent JAEA fiber (75.1 g/kg), was obtained. This new type of trunk fibers can be used for grafting a variety of uranium-interacting ligands, including designed ligands that are highly selective toward uranium.« less

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

    SciTech Connect

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

    2015-09-30

    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

  17. Selection and evaluation of adsorbents for the removal of anionic surfactants from laundry rinsing water.

    PubMed

    Schouten, Natasja; van der Ham, Louis G J; Euverink, Gert-Jan W; de Haan, André B

    2007-10-01

    Low-cost adsorbents were tested to remove anionic surfactants from laundry rinsing water to allow re-use of water. Adsorbents were selected corresponding to the different surfactant adsorption mechanisms. Equilibrium adsorption studies of linear alkyl benzene sulfonate (LAS) show that ionic interaction results in a high maximum adsorption capacity on positively charged adsorbents of 0.6-1.7 gLAS/g. Non-ionic interactions, such as hydrophobic interactions of LAS with non-ionic resins or activated carbons, result in a lower adsorption capacity of 0.02-0.6 gLAS/g. Negatively charged materials, such as cation exchange resins or bentonite clay, have negligible adsorption capacities for LAS. Similar results are obtained for alpha olefin sulfonate (AOS). Cost comparison of different adsorbents shows that an inorganic anion exchange material (layered double hydroxide) and activated carbons are the most cost-effective materials in terms of the amount of surfactant adsorbed per dollar worth of adsorbent.

  18. Determination of Points of Zero Charge of Natural and Treated Adsorbents

    NASA Astrophysics Data System (ADS)

    Nasiruddin Khan, M.; Sarwar, Anila

    Although particle size and its measurement are intuitively familiar to particle technologists, the concept of point of zero charge (pzc) is less widely understood and applied. This is unfortunate since it is at least as fundamentally important as particle size in determining the behavior of particulate materials, especially those with sizes in the colloidal range below a micrometer. pzc is related to the charge on the surface of the particle and strongly depends on the pH of the material; so it influences a wide range of properties of colloidal materials, such as their stability, interaction with electrolytes, suspension rheology, and ion exchange capacity. The pH dependence of surface charges was quantified for four different adsorbent-aqueous solution interfaces. The points of zero charge were determined for activated charcoal, granite sand, lakhra coal, and ground corn cob materials using three methods: (1) the pH drift method, measuring pH where the adsorbent behaves as a neutral specie; (2) potentiometric titration, measuring the adsorption of H+ and OH- on surfaces in solutions of varying ionic strengths; (3) direct assessment of the surface charge via nonspecific ion adsorption as a function of pH. The intrinsic acidity constants for acid and base equilibria, pK a1 s and pK a2 s, were also calculated. Lakhra coal was found to have the lowest pzc value among all other adsorbents studied owing to the presence of a large amount of humus material. The results were used to explain general connections among points of zero charges, cation exchange capacity, and base saturation % of adsorbents.

  19. Intracellular calcium is a target of modulation of apoptosis in MCF-7 cells in the presence of IgA adsorbed to polyethylene glycol

    PubMed Central

    Honorio-França, Adenilda Cristina; Nunes, Gabriel Triches; Fagundes, Danny Laura Gomes; de Marchi, Patrícia Gelli Feres; Fernandes, Rubian Trindade da Silva; França, Juliana Luzia; França-Botelho, Aline do Carmo; Moraes, Lucélia Campelo Albuquerque; Varotti, Fernando de Pilla; França, Eduardo Luzía

    2016-01-01

    Purpose Clinical and epidemiological studies have indicated that breastfeeding has a protective effect on breast cancer risk. Protein-based drugs, including antibodies, are being developed to attain better forms of cancer therapy. Secretory IgA (SIgA) is the antibody class in human breast milk, and its activity can be linked to the protective effect of breastfeeding. The aim of this study was to investigate the effect of polyethylene glycol (PEG) microspheres with adsorbed SIgA on MCF-7 human breast cancer cells. Methods The PEG microspheres were characterized by flow cytometry and fluorescence microscopy. The MCF-7 cells were obtained from American Type Culture Collection. MCF-7 cells were pre-incubated for 24 hours with or without SIgA (100 ng/mL), PEG microspheres or SIgA adsorbed in PEG microspheres (100 ng/mL). Viability, intracellular calcium release, and apoptosis in MCF-7 cells were determined by flow cytometry. Results Fluorescence microscopy and flow cytometry analyses revealed that SIgA was able to adsorb to the PEG microspheres. The MCF-7 cells that were incubated with PEG microspheres with adsorbed SIgA showed decreased viability. MCF-7 cells that were incubated with SIgA or PEG microspheres with adsorbed SIgA had increased intracellular Ca2+ levels. In the presence of SIgA, an increase in the percentage of apoptotic cells was observed. The highest apoptosis index was observed when the cells were treated with PEG microspheres with adsorbed SIgA. Conclusion These data suggest that colostral SIgA adsorbed to PEG microspheres has antitumor effects on human MCF-7 breast cancer cells and that the presence of large amounts of this protein in secreted breast milk may provide protection against breast tumors in women who breastfed. PMID:26893571

  20. Nitric oxide releasing material adsorbs more fibrinogen.

    PubMed

    Lantvit, Sarah M; Barrett, Brittany J; Reynolds, Melissa M

    2013-11-01

    One mechanism of the failure of blood-contacting devices is clotting. Nitric oxide (NO) releasing materials are seen as a viable solution to the mediation of surface clotting by preventing platelet activation; however, NO's involvement in preventing clot formation extends beyond controlling platelet function. In this study, we evaluate NO's effect on factor XII (fibrinogen) adsorption and activation, which causes the initiation of the intrinsic arm of the coagulation cascade. This is done by utilizing a model plasticized poly(vinyl) chloride (PVC), N-diazeniumdiolate system and looking at the adsorption of fibrinogen, an important clotting protein, to these surfaces. The materials have been prepared in such a way to eliminate changes in surface properties between the control (plasticized PVC) and composite (NO-releasing) materials. This allows us to isolate NO release and determine the effect on the adsorption of fibrinogen, to the material surface. Surprisingly, it was found that an NO releasing material with a surface flux of 17.4 ± 0.5 × 10(-10) mol NO cm(-2) min(-1) showed a significant increase in the amount of fibrinogen adsorbed to the material surface compared to one with a flux of 13.0 ± 1.6 × 10(-10) mol NO cm(-2) min(-1) and the control (2334 ± 496, 226 ± 99, and 103 ±31% fibrinogen adsorbed of control, respectively). This study suggests that NO's role in controlling clotting is extended beyond platelet activation. PMID:23554300

  1. Establishment of hepatitis A vaccine (inactivated, non-adsorbed) BRP batches 2 and 3.

    PubMed

    Morgeaux, S; Manniam, I; Variot, P; Buchheit, K H; Daas, A; Wierer, M; Costanzo, A

    2015-01-01

    The current hepatitis A vaccine (HAV), inactivated, non-adsorbed, European Pharmacopoeia (Ph. Eur.) Biological Reference Preparation (BRP) is used for the in vitro potency assay of HAV as prescribed by the Ph. Eur. general chapter 2.7.14 Assay of hepatitis A vaccine. This reference preparation was calibrated in 2008 through an international collaborative study and was assigned a potency of 12 IU/mL. During use of this BRP it appeared to be inapplicable in certain cases due to a low nominal antigen content. Consequently, the European Directorate for the Quality of Medicines and HealthCare (EDQM) established replacement batches for this BRP, calibrated against the 1(st) WHO International Standard (IS) for HAV (inactivated), using the standard in vitro ELISA (enzyme-linked immunosorbent assay) method validated previously. The results of the study showed that the candidate BRPs were suitable for the intended purpose, and following completion of the study, they were adopted in November 2014 by the Ph. Eur. Commission as HAV (inactivated, non-adsorbed) BRP batches 2 and 3, with an assigned potency of 1350 IU/mL, for in vitro antigen content determination by ELISA. As the amount of material in each vial largely exceeds the amount required for the performance of a single assay, the BRPs are to be aliquoted by users as single-use aliquots and refrozen below -50 °C prior to their use as reference preparations.

  2. High capacity cryogel-type adsorbents for protein purification.

    PubMed

    Singh, Naveen Kumar; Dsouza, Roy N; Grasselli, Mariano; Fernández-Lahore, Marcelo

    2014-08-15

    Cryogel bodies were modified to obtain epoxy groups by graft-copolymerization using both chemical and gamma irradiation initiation techniques. The free epoxy adsorbents were reacted further to introduce diethylaminoethanol (DEAE) functionalities. The resulting weak anion-exchange cryogel adsorbents showed dynamic binding capacities of ca. 27±3mg/mL, which was significantly higher than previously reported for this type of adsorbent material. Gamma irradiated grafting initiation showed a 4-fold higher capacity for proteins than chemical grafting initiation procedures. The phosphate capacity for these DEAE cryogels was 119mmol/L and also showed similar column efficiency as compared to commercial adsorbents. The large pores in the cryogel structure ensure convective transport of the molecules to active binding sites located on the polymer-grafted surface of cryogels. However, as cryogels have relatively large pores (10-100μm), the BET area available for surface activation is low, and consequently, the capacity of the cryogels is relatively low for biomolecules, especially when compared to commercial beaded adsorbents. Nevertheless, we have shown that gamma ray mediated surface grafting of cryogel matrices greatly enhance their functional and adsorptive properties.

  3. High capacity cryogel-type adsorbents for protein purification.

    PubMed

    Singh, Naveen Kumar; Dsouza, Roy N; Grasselli, Mariano; Fernández-Lahore, Marcelo

    2014-08-15

    Cryogel bodies were modified to obtain epoxy groups by graft-copolymerization using both chemical and gamma irradiation initiation techniques. The free epoxy adsorbents were reacted further to introduce diethylaminoethanol (DEAE) functionalities. The resulting weak anion-exchange cryogel adsorbents showed dynamic binding capacities of ca. 27±3mg/mL, which was significantly higher than previously reported for this type of adsorbent material. Gamma irradiated grafting initiation showed a 4-fold higher capacity for proteins than chemical grafting initiation procedures. The phosphate capacity for these DEAE cryogels was 119mmol/L and also showed similar column efficiency as compared to commercial adsorbents. The large pores in the cryogel structure ensure convective transport of the molecules to active binding sites located on the polymer-grafted surface of cryogels. However, as cryogels have relatively large pores (10-100μm), the BET area available for surface activation is low, and consequently, the capacity of the cryogels is relatively low for biomolecules, especially when compared to commercial beaded adsorbents. Nevertheless, we have shown that gamma ray mediated surface grafting of cryogel matrices greatly enhance their functional and adsorptive properties. PMID:24980092

  4. Effect of cation on HTO / H{sub 2}O separation and dehydration characteristics of Y-type zeolite adsorbent

    SciTech Connect

    Iwai, Y.; Uzawa, M.; Yamanishi, T.

    2008-07-15

    Several types of adsorbers have been studied as they are considered for the first stage of water detritiation systems processing more than 100 kg/h of high-level tritiated water generated in a future fusion plant. Zeolite is a suitable adsorbent since it is an inorganic material having a large water capacity. Rapid dehydration characteristics as well as a large HTO/H{sub 2}O separation factor is necessary for the adsorber to minimize its size. Present experiments were focused on the effect of cations on HTO /H{sub 2}O separation and dehydration characteristics of Y-type zeolites. The selected cations are Na, K and Ca. The framework SiO{sub 2}/Al{sub 2}O{sub 3} ratio of the zeolites is fixed to 5.0 in the present experiments. It was found that the isotope separation factors are around 1.1-1.2 under static conditions. As for dehydration, operating temperature fixes the capacity of movable water from the zeolites. The capacity at room temperature is NaY > CaY > KY. HTO dehydration characteristics depend on the accumulated purge gas amount, while the purge gas rate is less influential. Effect of temperature on HTO dehydration is also less influential especially in the early stage of dehydration. Pressure swing is an effective method for HTO dehydration. (authors)

  5. Supercritical fluid regeneration of adsorbents

    NASA Astrophysics Data System (ADS)

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

    1983-05-01

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

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

    PubMed Central

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

    2015-01-01

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

  7. Comprehensive study of mesoporous carbon functionalized with carboxylate groups and magnetic nanoparticles as a promising adsorbent.

    PubMed

    Chi, Yue; Geng, Wangchang; Zhao, Liang; Yan, Xiao; Yuan, Qing; Li, Nan; Li, Xiaotian

    2012-03-01

    Highly ordered mesoporous carbon functionalized with carboxylate groups and magnetic nanoparticles has been successfully synthesized. By oxidative treatment using (NH(4))(2)S(2)O(8) and H(2)SO(4) mixed solution, numerous hydrophilic groups were created in the mesopores without destroying the ordered mesostructure of CMK-3. Through the in situ reduction in Fe(3+), magnetic nanoparticles were successfully introduced into the mesopores, resulting in the multifunctional mesoporous carbon Fe-CMK-3. The obtained hybrid carbon material possesses ordered mesostructure, high Brunauer-Emmett-Teller (BET) surface area up to 1013 m(2)/g, large pore volume of about 1.16 cm(3)/g, carboxylic surface, and excellent magnetic property. When used as an adsorbent, Fe-CMK-3 exhibits excellent performances for removing toxic organic compounds from waster-water, with a high adsorption capacity, an extremely rapid adsorption rate, and an easy magnetically separable process. In the case of requiring emergency removal of large amount of organic pollutants in aqueous, the hybrid carbon adsorbent would be an ideal choice.

  8. Method And Apparatus For Regenerating Nox Adsorbers

    DOEpatents

    Driscoll, J. Joshua; Endicott, Dennis L.; Faulkner, Stephen A.; Verkiel, Maarten

    2006-03-28

    Methods and apparatuses for regenerating a NOx adsorber coupled with an exhaust of an engine. An actuator drives a throttle valve to a first position when regeneration of the NOx adsorber is desired. The first position is a position that causes the regeneration of the NOx adsorber. An actuator drives the throttle valve to a second position while regeneration of the NOx adsorber is still desired. The second position being a position that is more open than the first position and operable to regenerate a NOx adsorber.

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

    SciTech Connect

    Sun, Baichuan; Chakraborty, Anutosh

    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.

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

    NASA Astrophysics Data System (ADS)

    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.

  11. Ultraviolet and electron radiation induced fragmentation of adsorbed ferrocene

    SciTech Connect

    Welipitiya, D.; Green, A.; Woods, J.P.; Dowben, P.A.; Robertson, B.W.; Byun, D.; Zhang, J.

    1996-06-01

    From thermal desorption spectroscopy we find that ferrocene, Fe(C{sub 5}H{sub 5}){sub 2}, adsorbs and desorbs associatively on Ag(100). Photoemission results indicate that the initially adsorbed surface species closely resembles that of molecular ferrocene. The shift in photoemission binding energies relative to the gas phase is largely independent of the molecular orbital. We find that ultraviolet light does lead to partial fragmentation of the ferrocene and that the molecular fragments are much more strongly bound to the surface than the associatively adsorbed ferrocene. Since fragmentation occurs only in the presence of incident radiation, selective area deposition from this class of molecules is possible. Using a focused electron beam in a scanning transmission electron microscope, we show that selective area deposition of features with resolution of a few hundred angstroms is readily achieved. {copyright} {ital 1996 American Institute of Physics.}

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

    NASA Astrophysics Data System (ADS)

    Ito, D.; Nishimura, K.; Miura, O.

    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.

  13. Oil adsorbent produced by the carbonization of rice husks.

    PubMed

    Kumagai, Seiji; Noguchi, Yosuke; Kurimoto, Yasuji; Takeda, Koichi

    2007-01-01

    In this study, rice husks considered to be agricultural waste are converted into an adsorbent intended for use in the disposal of oil spills. The raw and refined (defiberized) husks of Japanese Akita Komachi rice were pyrolyzed in a vacuum (500 Pa) at 300-800 degrees C. The amount of A-heavy and B-heavy oils adsorbed on the carbonized rice husk were then evaluated. Oil adsorption is dependent on the type of oil. Rice husks refined and then pyrolyzed at 600-700 degrees C (1.0 g) adsorbed >6.0 g of B-heavy oil and <1.5 g of water, which indicates their usefulness as an adsorbent for oil spill cleanup in Japan. The refining process contributes to an improvement in the oil adsorption capacity, while the carbonization time (at 600 degrees C) has only a minor influence. The residual fluid components in the carbonized rice husks, rather than their porosity, are closely related to oil adsorption capacity.

  14. Evaluation of gaseous fluorocarbon adsorption isotherms on porous adsorbents under high pressure

    SciTech Connect

    Kaliappan, S.; Furuya, E.G.; Noll, K.E.; Chang, H.T.; Wang, H.C.

    1996-11-01

    In this study data have been collected to aid in the design of a control system that will remove fluorocarbons by adsorbing onto porous adsorbents. A bench scale experimental adsorption system had been designed using high accuracy MKS pressure transducers of 10,000 torr (two nos.) and a 100 torr connected to digital readout units. Tetrafluoromethane (CF{sub 4}) one of the fluorinated carbon family has been selected to evaluate the adsorption characteristics on porous adsorbents. The CF{sub 4} was charged to a sample reservoir in the test system at 200 psig pressure and at 22 C was allowed into an adsorption chamber at small increment of pressure rise. The pressure drop, using a Valydine PS 309 differential pressure gauge from the sample reservoir and the pressure buildup in the adsorption chamber were measured and the amount of CF{sub 4} adsorbed onto the adsorbents was calculated using ideal gas law. Various adsorbents, molecular sieve 13X, Silicagel (14 x 20), Beads Activated Carbon, Granular Activated Carbons PCB 6 x 16, BPL 4 x 10, F300, and F400 had been studied. It has been found that GAC-PCB 6 x 16 has the highest adsorbing capacity of 0.51 gm/gm at the conditions established. GAC-F300 had the second highest adsorbing capacity of 0.413 gm/gm, among all the adsorbents tested. The isotherms were analyzed using several equations employing both two parameters and three parameters. The relationship between the constants and physical properties of adsorbent solids and adsorbate molecules is discussed. The result of this study will be utilized to design a pressure swing fluorocarbon adsorption system that can be economically (using recycle of the collected fluorocarbons) applied to fluorocarbon removal in the electronic industry.

  15. Extraction of palladium from acidic solutions with the use of carbon adsorbents

    SciTech Connect

    O.N. Kononova; N.G. Goryaeva; N.B. Dostovalova; S.V. Kachin; A.G. Kholmogorov

    2007-08-15

    We studied the sorption of palladium(II) on LKAU-4, LKAU-7, and BAU carbon adsorbents from model hydrochloric acid solutions and the solutions of spent palladium-containing catalysts. It was found that sorbents based on charcoal (BAU) and anthracite (LKAU-4) were characterized by high sorption capacities for palladium. The kinetics of the saturation of carbon adsorbents with palladium(II) ions was studied, and it was found that more than 60% of the initial amount of Pd(II) was recovered in a 1-h contact of an adsorbent with a model solution. This value for the solutions of spent catalysts was higher than 35%.

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

    PubMed

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

    2016-08-01

    Zinc oxide (ZnO)-coated zeolite adsorbents were developed by both nitric acid modification and Zn(NO3)2·6H2O functionalization of zeolite 4A. The developed adsorbents were used for the removal of humic acid (HA) from aqueous solutions. The synthesized materials were characterized by porosimetry analysis, scanning electron microscopy, X-Ray diffraction analysis, and high resolution transmission electron microscopy. The maximum adsorption capacity of the adsorbents at 21±1°C was about 60mgCg(-1). The results showed that the positive charge density of ZnO-coated zeolite adsorbents was proportional to the amount of ZnO coated on zeolite and thus, ZnO-coated zeolite adsorbents exhibited a greater affinity for negatively charged ions. Furthermore, the adsorption capacity of ZnO-coated zeolite adsorbents increased markedly after acid modification. Adsorption experiments demonstrated ZnO-coated zeolite adsorbents possessed high adsorption capacity to remove HA from aqueous solutions mainly due to strong electrostatic interactions between negative functional groups of HA and the positive charges of ZnO-coated zeolite adsorbents.

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

    NASA Astrophysics Data System (ADS)

    Magkoev, T. T.

    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.

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

    NASA Astrophysics Data System (ADS)

    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.

  19. Development of carbon dioxide adsorbent from rice husk char

    NASA Astrophysics Data System (ADS)

    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.

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

    NASA Astrophysics Data System (ADS)

    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

  1. Probing interactions between TiO 2 photocatalyst and adsorbing species using quartz crystal microbalance

    NASA Astrophysics Data System (ADS)

    Morand, R.; Noworyta, K.; Augustynski, J.

    2002-10-01

    Photoactivity of nanocrystalline TiO 2 films is shown to be strongly affected by the presence in aqueous solution of salicylic acid, known to form Ti(IV)salicylate surface complexes. In particular, the photooxidation of methanol - an effective hole scavenger - at TiO 2 appears to be in part, or even completely inhibited by the additions of increasing amounts of salicylic acid. The chemisorption of salicylic and also phthalic acid on TiO 2 was followed using quartz crystal microbalance, QCM. The observed resonant frequency changes of the quartz crystal bearing TiO 2 films, accompanying increasing additions of the benzoic acids to the contacting solutions, indicate large displacement of water as a consequence of the adsorbent-imparted hydrophobicity of the interface.

  2. A novel fiber-based adsorbent technology

    SciTech Connect

    Reynolds, T.A.

    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.

  3. Quasiparticle excitations of adsorbates on doped graphene

    NASA Astrophysics Data System (ADS)

    Lischner, Johannes; Wickenburg, Sebastian; Wong, Dillon; Karrasch, Christoph; Wang, Yang; Lu, Jiong; Omrani, Arash A.; Brar, Victor; Tsai, Hsin-Zon; Wu, Qiong; Corsetti, Fabiano; Mostofi, Arash; Kawakami, Roland K.; Moore, Joel; Zettl, Alex; Louie, Steven G.; Crommie, Mike

    Adsorbed atoms and molecules can modify the electronic structure of graphene, but in turn it is also possible to control the properties of adsorbates via the graphene substrate. In my talk, I will discuss the electronic structure of F4-TCNQ molecules on doped graphene and present a first-principles based theory of quasiparticle excitations that captures the interplay of doping-dependent image charge interactions between substrate and adsorbate and electron-electron interaction effects on the molecule. The resulting doping-dependent quasiparticle energies will be compared to experimental scanning tunnelling spectra. Finally, I will also discuss the effects of charged adsorbates on the electronic structure of doped graphene.

  4. EVALUATION OF SOLID ADSORBENTS FOR THE COLLECTION AND ANALYSES OF AMBIENT BIOGENIC VOLATILE ORGANICS

    EPA Science Inventory

    Micrometeorological flux measurements of biogenic volatile organic compounds (BVOCs) usually require that large volumes of air be collected (whole air samples) or focused during the sampling process (cryogenic trapping or gas-solid partitioning on adsorbents) in order to achiev...

  5. Adsorption characteristics of water vapor on gear-pellet and honeycomb-pellet types of adsorbents containing A-type zeolite

    SciTech Connect

    Nakamura, A.; Munakata, K.; Hara, K.; Narita, S.; Sugiyama, T.; Kotoh, K.; Tanaka, M.; Uda, T.

    2015-03-15

    It is necessary to recover or process tritiated species that are extensively coexistent in nuclear fusion installations. A conventional way to recover tritium release to atmosphere is catalytic oxidation of tritiated species and adsorption of tritiated water vapor on adsorbents with high surface areas. Therefore, new adsorbents with low pressure loss and high surface areas need to be developed and utilized for such large-scale adsorption systems. In this study, attention was focused on new adsorbents, which are gear-type pellet MS5A adsorbent, gear-type pellet MS4A adsorbent and honeycomb-type pellet MS5A adsorbent. The adsorption characteristics of the new adsorbent were comparatively studied with conventional type of adsorbents (pellet-type MS5A adsorbent and pebble-type MS5A adsorbent), in terms of adsorption capacity, pressure loss and adsorption rate. It was found that the adsorption capacity of water vapor on the gear-type adsorbents is higher than that on a honeycomb-type adsorbent. The experimental breakthrough curves indicate that the adsorption rates of water vapor on gear-type and honeycomb-type adsorbents are smaller than that on conventional type adsorbents. Various adsorption models were also tested to correlate the experimental isotherms. It was found that the Langmuir-Freundlich model could properly correlate the experimental adsorption isotherms.

  6. The uranium from seawater program at PNNL: Overview of marine testing, adsorbent characterization, adsorbent durability, adsorbent toxicity, and deployment studies

    DOE PAGES

    Gill, Gary A.; Kuo, Li -Jung; Janke, Christopher James; Park, Jiyeon; Jeters, Robert T.; Bonheyo, George T.; Pan, Horng -Bin; Wai, Chien; Khangaonkar, Tarang P.; Bianucci, Laura; et al

    2016-02-07

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

  7. Visualization and Measurement of Adsorption/Desorption Process of Ethanol in Activated Carbon Adsorber

    NASA Astrophysics Data System (ADS)

    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.

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

    SciTech Connect

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

    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.

  9. Database of Novel and Emerging Adsorbent Materials

    National Institute of Standards and Technology Data Gateway

    SRD 205 NIST/ARPA-E Database of Novel and Emerging Adsorbent Materials (Web, free access)   The NIST/ARPA-E Database of Novel and Emerging Adsorbent Materials is a free, web-based catalog of adsorbent materials and measured adsorption properties of numerous materials obtained from article entries from the scientific literature. Search fields for the database include adsorbent material, adsorbate gas, experimental conditions (pressure, temperature), and bibliographic information (author, title, journal), and results from queries are provided as a list of articles matching the search parameters. The database also contains adsorption isotherms digitized from the cataloged articles, which can be compared visually online in the web application or exported for offline analysis.

  10. NOx adsorber and method of regenerating same

    DOEpatents

    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.

  11. Fluorescence dynamics of microsphere-adsorbed sunscreens

    NASA Astrophysics Data System (ADS)

    Krishnan, R.

    2005-03-01

    Sunscreens are generally oily substances which are prepared in organic solvents, emulsions or dispersions with micro- or nanoparticles. These molecules adsorb to and integrate into skin cells. In order to understand the photophysical properties of the sunscreen, we compare steady-state and time-resolved fluorescence in organic solvent of varying dielectric constant ɛ and adsorbed to polystyrene microspheres and dispersed in water. Steady-state fluorescence is highest and average fluorescence lifetime longest in toluene, the solvent of lowest ɛ. However, there is no uniform dependence on ɛ. Sunscreens PABA and padimate-O show complex emission spectra. Microsphere-adsorbed sunscreens exhibit highly non-exponential decay, illustrative of multiple environments of the adsorbed molecule. The heterogeneous fluorescence dynamics likely characterizes sunscreen adsorbed to cells.

  12. [Synthesis and application of the polyacrylamide beads acting as LDL adsorbent's matrices].

    PubMed

    Yu, Xixun; Li, Li; Yue, Yilun; Chen, Huaiqing

    2004-08-01

    This study in pursuit of the synthetic technologies and structure characterization of polyacrylamide-based matrices (PAM beads) for low density lipoprotein (LDL) adsorbent and their adsorbability for LDL was intended for an experimental evidence of developing advanced matrices for LDL adsorbent. PAM beads were synthesized by inverse suspension polymerization, and their structure characterization was characterized by SEM, image analyzer and small angle X-ray scattering. The tripeptide serine-aspartic-glutamic acid (SDE) was coupled on the PAM beads to prepare the LDL adsorbents whose adsorbability for LDL was determined in vitro. The results showed that the PAM beads with the average size diameter 142.1 microm and the average pore diameter 119.8 nm could act as the matrices in accordance with the requirement of adsorbent for LDL. When the amount of acrylamide and the crosslinking agent N,N'-methylene-bis(acrylamide) was fixed, the average pore diameter decreased with the increase of the crosslinking agent content. Although the nonspecific binding of PAM beads for LDL was low, they could selectively adsorb LDL after coupling the SDE on the PAM beads.

  13. [Synthesis and application of the polyacrylamide beads acting as LDL adsorbent's matrices].

    PubMed

    Yu, Xixun; Li, Li; Yue, Yilun; Chen, Huaiqing

    2004-08-01

    This study in pursuit of the synthetic technologies and structure characterization of polyacrylamide-based matrices (PAM beads) for low density lipoprotein (LDL) adsorbent and their adsorbability for LDL was intended for an experimental evidence of developing advanced matrices for LDL adsorbent. PAM beads were synthesized by inverse suspension polymerization, and their structure characterization was characterized by SEM, image analyzer and small angle X-ray scattering. The tripeptide serine-aspartic-glutamic acid (SDE) was coupled on the PAM beads to prepare the LDL adsorbents whose adsorbability for LDL was determined in vitro. The results showed that the PAM beads with the average size diameter 142.1 microm and the average pore diameter 119.8 nm could act as the matrices in accordance with the requirement of adsorbent for LDL. When the amount of acrylamide and the crosslinking agent N,N'-methylene-bis(acrylamide) was fixed, the average pore diameter decreased with the increase of the crosslinking agent content. Although the nonspecific binding of PAM beads for LDL was low, they could selectively adsorb LDL after coupling the SDE on the PAM beads. PMID:15357437

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

    PubMed

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

    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.

  15. MOFs as adsorbents for low temperature heating and cooling applications.

    PubMed

    Henninger, Stefan K; Habib, Hesham A; Janiak, Christoph

    2009-03-01

    The 3D metal-organic framework (MOF) (3)(infinity){[Ni(3)(mu(3)-btc)(2)(mu(4)-btre)(2)(mu-H(2)O)(2)]. approximately 22H(2)O} is found to be a reversibly dehydratable-hydratable water-stable MOF material with a large loading spread of 210 g/kg as a candidate for solid adsorbents in heat transformation cycles for refrigeration, heat pumping, and heat storage. PMID:19206233

  16. The effect of mineral bond strength and adsorbed water on fault gouge frictional strength

    USGS Publications Warehouse

    Morrow, C.A.; Moore, Diane E.; Lockner, D.A.

    2000-01-01

    Recent studies suggest that the tendency of many fault gouge minerals to take on adsorbed or interlayer water may strongly influence their frictional strength. To test this hypothesis, triaxial sliding experiments were conducted on 15 different single-mineral gouges with various water-adsorbing affinities. Vacuum dried samples were sheared at 100 MPa, then saturated with water and sheared farther to compare dry and wet strengths. The coefficients of friction, μ, for the dry sheet-structure minerals (0.2-0.8), were related to mineral bond strength, and dropped 20-60% with the addition of water. For non-adsorbing minerals (μ = 0.6-0.8), the strength remained unchanged after saturation. These results confirm that the ability of minerals to adsorb various amounts of water is related to their relative frictional strengths, and may explain the anomalously low strength of certain natural fault gouges.

  17. Effect of adsorbed chlorine and oxygen on shear strength of iron and copper junctions

    NASA Technical Reports Server (NTRS)

    Wheeler, D. R.

    1975-01-01

    Static friction experiments were performed in ultrahigh vacuum at room temperature on copper, iron, and steel contacts selectively contaminated with oxygen and chlorine in submonolayer amounts. The concentration of the adsorbates was determined with Auger electron spectroscopy and was measured relative to the saturation concentration of oxygen on iron (concentration 1.0). The coefficient of static friction decreased with increasing adsorbate concentration. It was independent of the metal and the adsorbate. The results compared satisfactorily with an extension of the junction growth theory to heterogeneous interfaces. The reduction in interfacial shear strength was measured by the ratio sub a/sub m where sub a is the shear strength of the interface with an adsorbate concentration of 1.0, and sub m is the strength of the clean metal interface. This ratio was 0.835 + or - 0.012 for all the systems tested.

  18. Effect of adsorbed chlorine and oxygen on the shear strength of iron and copper junctions

    NASA Technical Reports Server (NTRS)

    Wheeler, D. R.

    1976-01-01

    Static-friction experiments were performed in ultrahigh vacuum at room temperature on copper, iron, and steel contacts selectively contaminated with oxygen and chlorine in submonolayer amounts. The concentration of the adsorbates was determined with Auger electron spectroscopy and was measured relative to the saturation concentration of oxygen on iron (concentration, 1.0). The coefficient of static friction decreased with increasing adsorbate concentration; however, it was independent of the type of metal and the adsorbate species. The results compared satisfactorily with an extension of the junction growth theory to heterogeneous interfaces. The reduction in interfacial shear strength was measured by the ratio of the shear strength of the interface with an adsorbate concentration of 1.0 and the strength of the clean metal interface. This ratio was about 0.835 for all the systems tested.

  19. Inorganic chemically active adsorbents (ICAAs)

    SciTech Connect

    Ally, M.R.; 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.

  20. Characterization of carbon cryogel microspheres as adsorbents for VOC.

    PubMed

    Yamamoto, Takuji; Kataoka, Sho; Ohmori, Takao

    2010-05-15

    Adsorption characteristics of carbon cryogel microspheres (CC microspheres) with controlled porous structure composed of mesopores (2 nmadsorbents for a volatile organic compound (VOC). The amount of toluene, as a model VOC, adsorbed on the CC microspheres could be changed by varying either the size of the mesopores or the volume of the micropores. The peak temperature of the temperature-programmed desorption profiles of toluene from the CC microspheres was higher than that from granular activated carbon (GAC) with numerous micropores, indicating that toluene is adsorbed more strongly on CC microspheres than on GAC. To permit the practical use of CC microspheres, the adsorption characteristic of moisture on CC microspheres and GAC were evaluated. The effect of adsorption of moisture on the gas permeation property of an adsorption module prepared from the CC microspheres was also examined. PMID:20042276

  1. Detection of adsorbed water and hydroxyl on the moon

    USGS Publications Warehouse

    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.

  2. Detection of adsorbed water and hydroxyl on the Moon.

    PubMed

    Clark, Roger N

    2009-10-23

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

  3. Titanium-incorporated organic–inorganic hybrid adsorbent for improved CO{sub 2} adsorption performance

    SciTech Connect

    Zhang, Xiaoyun; Qin, Hongyan; Zhang, Sisi; Wu, Wei

    2015-02-15

    Highlights: • Titanium-incorporated organic–inorganic hybrid adsorbent was prepared. • The incorporation of Ti to the adsorbent showed significant effect. • The sorbent shows high CO{sub 2} capture capacity both in pure and diluted CO{sub 2} at RT. • The sorbent exhibits a high recycling stability after 15 cycling runs. - Abstract: The CO{sub 2} adsorption performance of acrylonitrile (AN)–tetraethylenepentamine (TEPA) adduct (hereafter referred to as TN) impregnated adsorbent was greatly enhanced by introduction of Titanium atom into the silica matrix. The adsorbents were characterized by X-ray fluorescence spectrometry (XRF), X-ray diffraction (XRD), transmission electron microscopy (TEM), N{sub 2} adsorption/desorption, UV–vis spectroscopy, Fourier transform infrared (FTIR) spectroscopy. The adsorption experiments together with the physicochemical characterization demonstrated that these adsorbents containing an optimal amount of Titanium (Ti/Si ≈ 0.1) remarkably reinforced the CO{sub 2} adsorption capacity and recycling stability. The highest CO{sub 2} uptakes reached 4.65 and 1.80 mmol CO{sub 2}/g adsorbent at 25 °C under 90% CO{sub 2} (CO{sub 2}/N{sub 2}, 90:10 V/V) and 1% CO{sub 2} (CO{sub 2}/N{sub 2}, 1:99 V/V) conditions for sample Ti(0.1)-DMS-TN, respectively. Repeated adsorption/desorption cycles revealed that the Ti-incorporated adsorbent showed only a tiny decrease in adsorption capacity (1.778 mmol CO{sub 2}/g adsorbent after 15 cycles, decreased by 0.95%), significantly enhanced the adsorbent recycling stability.

  4. States of water adsorbed on perindopril crystals

    NASA Astrophysics Data System (ADS)

    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.

  5. Volumetric Interpretation of Protein Adsorption: Capacity Scaling with Adsorbate Molecular Weight and Adsorbent Surface Energy

    PubMed Central

    Parhi, Purnendu; Golas, Avantika; Barnthip, Naris; Noh, Hyeran; Vogler, Erwin A.

    2009-01-01

    Silanized-glass-particle adsorbent capacities are extracted from adsorption isotherms of human serum albumin (HSA, 66 kDa), immunoglobulin G (IgG, 160 kDa), fibrinogen (Fib, 341 kDa), and immunoglobulin M (IgM, 1000 kDa) for adsorbent surface energies sampling the observable range of water wettability. Adsorbent capacity expressed as either mass-or-moles per-unit-adsorbent-area increases with protein molecular weight (MW) in a manner that is quantitatively inconsistent with the idea that proteins adsorb as a monolayer at the solution-material interface in any physically-realizable configuration or state of denaturation. Capacity decreases monotonically with increasing adsorbent hydrophilicity to the limit-of-detection (LOD) near τo = 30 dyne/cm (θ~65o) for all protein/surface combinations studied (where τo≡γlvocosθ is the water adhesion tension, γlvo is the interfacial tension of pure-buffer solution, and θ is the buffer advancing contact angle). Experimental evidence thus shows that adsorbent capacity depends on both adsorbent surface energy and adsorbate size. Comparison of theory to experiment implies that proteins do not adsorb onto a two-dimensional (2D) interfacial plane as frequently depicted in the literature but rather partition from solution into a three-dimensional (3D) interphase region that separates the physical surface from bulk solution. This interphase has a finite volume related to the dimensions of hydrated protein in the adsorbed state (defining “layer” thickness). The interphase can be comprised of a number of adsorbed-protein layers depending on the solution concentration in which adsorbent is immersed, molecular volume of the adsorbing protein (proportional to MW), and adsorbent hydrophilicity. Multilayer adsorption accounts for adsorbent capacity over-and-above monolayer and is inconsistent with the idea that protein adsorbs to surfaces primarily through protein/surface interactions because proteins within second (or higher

  6. Preparation of DNA-adsorbed TiO2 particles--augmentation of performance for environmental purification by increasing DNA adsorption by external pH regulation.

    PubMed

    Amano, Takeharu; Toyooka, Tatsushi; Ibuki, Yuko

    2010-01-01

    We have previously developed a novel photocatalyst, DNA-attached titanium dioxide (DNA-TiO(2)), useful for the recovery and decomposition of chemicals [Suzuki et al. Environ. Sci. Technol. 42, 8076, 2008]. Chemicals accumulated in DNA near the surface of TiO(2) and were degraded under UV light. The efficiency of their removal was dependent on the amount of DNA adsorbed on TiO(2), indicating the attachment of larger amounts of DNA to result in higher efficiency. In this study, we succeeded in improving the performance of DNA-TiO(2) by increasing the amount of DNA adsorbed by regulating the external pH. The adsorption of DNA by TiO(2) dramatically increased at pH2, to about fourfold that at other pH values (pH4-10). Repeating the process of DNA addition increased the adsorption further. The attached DNA was stable on the surface of TiO(2) at pH2-10 and 4-56 degrees C, the same as DNA-TiO(2) prepared at pH7. As the DNA-TiO(2) prepared at pH2 retained much DNA on its surface, chemicals (methylene blue, ethidium bromide, etc.) which could intercalate or react with DNA were effectively removed from solutions. The photocatalytic degradation was slow at first, but the final degradation rate was higher than for non-adsorbed TiO(2) and DNA-TiO(2) prepared at pH7. These results indicated that preparation of DNA-TiO(2) at pH2 has advantages in that much DNA can be attached and large amounts of chemicals can be concentrated in the DNA, resulting in extensive decomposition under UV light.

  7. Morphological characterization of furfuraldehyde resins adsorbents

    SciTech Connect

    Sanchez, R.; Monteiro, S.N.; D`Almeida, J.R.

    1996-12-31

    Sugar cane is one of the most traditional plantation cultivated crops in large areas in Brazil. The State University of the North of Rio de Janeiro, UENF, is currently engaged in a program aimed to exploit the potentialities of sugar cane industry as a self sustained non-polluting enterprise. One of the projects being carried out at the UENF is the transformation of sugar cane bagasse in precursor materials for the industry of furan derivatives such as the furfuraldehyde resins obtained by acid catalysis. The possibility of employing acid catalyzed furfuraldehyde resins as selective adsorbents has arisen during a comprehensive study of physical-chemical adsorption properties of these materials. The morphology of these resins depend on the synthesis method. Scanning Electron Microscopic studies of these materials which were synthesized, in bulk (FH-M) and solution (FH-D), showed differences in surface density and particle size. Using mercury porosimeter techniques and BET adsorption methods, it was found different pore size distributions and a decrement in surface area when solvent was employed in the synthesis process. By thermogravimetric analysis it was found similar weight losses (6%) of water adsorption and a small differences in thermal stabilities.

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

    PubMed

    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

  9. Modeling diffusion of adsorbed polymer with explicit solvent.

    PubMed

    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.

  10. Allantoin as a solid phase adsorbent for removing endotoxins.

    PubMed

    Vagenende, Vincent; Ching, Tim-Jang; Chua, Rui-Jing; Gagnon, Pete

    2013-10-01

    In this study we present a simple and robust method for removing endotoxins from protein solutions by using crystals of the small-molecule compound 2,5-dioxo-4-imidazolidinyl urea (allantoin) as a solid phase adsorbent. Allantoin crystalline powder is added to a protein solution at supersaturated concentrations, endotoxins bind and undissolved allantoin crystals with bound endotoxins are removed by filtration or centrifugation. This method removes an average of 99.98% endotoxin for 20 test proteins. The average protein recovery is ∼80%. Endotoxin binding is largely independent of pH, conductivity, reducing agent and various organic solvents. This is consistent with a hydrogen-bond based binding mechanism. Allantoin does not affect protein activity and stability, and the use of allantoin as a solid phase adsorbent provides better endotoxin removal than anion exchange, polymixin affinity and biological affinity methods for endotoxin clearance.

  11. PERVAPORATION USING ADSORBENT-FILLED MEMBRANES

    EPA Science Inventory

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

  12. Regenerable activated bauxite adsorbent alkali monitor probe

    DOEpatents

    Lee, Sheldon H. D.

    1992-01-01

    A regenerable activated bauxite adsorber alkali monitor probe for field applications to provide reliable measurement of alkali-vapor concentration in combustion gas with special emphasis on pressurized fluidized-bed combustion (PFBC) off-gas. More particularly, the invention relates to the development of a easily regenerable bauxite adsorbent for use in a method to accurately determine the alkali-vapor content of PFBC exhaust gases.

  13. Regenerable activated bauxite adsorbent alkali monitor probe

    DOEpatents

    Lee, S.H.D.

    1992-12-22

    A regenerable activated bauxite adsorber alkali monitor probe for field applications to provide reliable measurement of alkali-vapor concentration in combustion gas with special emphasis on pressurized fluidized-bed combustion (PFBC) off-gas. More particularly, the invention relates to the development of a easily regenerable bauxite adsorbent for use in a method to accurately determine the alkali-vapor content of PFBC exhaust gases. 6 figs.

  14. Mesoporous Silica: A Suitable Adsorbent for Amines

    PubMed Central

    2009-01-01

    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. PMID:20628459

  15. Hydrophobic Porous Material Adsorbs Small Organic Molecules

    NASA Technical Reports Server (NTRS)

    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.

  16. A new soil test for quantitative measurement of available and adsorbed boron

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Boron soil tests currently in use, do not extract all plant available B but are used by relating the extractable amount of B to plant B content. There is a need to accurately measure all plant available or adsorbed B because B can be toxic to plants at elevated concentrations and can cause marked y...

  17. Direct Observation of the Photodegradation of Anthracene and Pyrene Adsorbed onto Mangrove Leaves

    PubMed Central

    Wang, Ping; Wu, Tun-Hua; Zhang, Yong

    2014-01-01

    An established synchronous fluorimetry method was used for in situ investigation of the photodegradation of pyrene (PYR) and anthracene (ANT) adsorbed onto fresh leaves of the seedlings of two mangrove species, Aegiceras corniculatum (L.) Blanco (Ac) and Kandelia obovata (Ko) in multicomponent mixtures (mixture of the ANT and PYR). Experimental results indicated that photodegradation was the main transformation pathway for both ANT and PYR in multicomponent mixtures. The amount of the PAHs volatilizing from the leaf surfaces and entering the inner leaf tissues was negligible. Over a certain period of irradiation time, the photodegradation of both PYR and ANT adsorbed onto the leaves of Ac and Ko followed first-order kinetics, with faster rates being observed on Ac leaves. In addition, the photodegradation rate of PYR on the leaves of the mangrove species in multicomponent mixtures was much slower than that of adsorbed ANT. Compared with the PAHs adsorbed as single component, the photodegradation rate of ANT adsorbed in multicomponent mixtures was slower, while that of PYR was faster. Moreover, the photodegradation of PYR and ANT dissolved in water in multicomponent mixtures was investigated for comparison. The photodegradation rate on leaves was much slower than in water. Therefore, the physical-chemical properties of the substrate may strongly influence the photodegradation rate of adsorbed PAHs. PMID:25144741

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

    PubMed

    Huang, Li; Xiao, Congming; Chen, Bingxia

    2011-08-30

    A novel effective starch-based adsorbent was prepared through two common reactions, which included the esterification of starch with excess maleic anhydride in the presence of pyridine and the cross-linking reaction of the obtained macromonomer with acrylic acid by using potassium persulphate as initiator. The percentage of carboxylic groups of the macromonomer ranged from 14% to 33.4%. The cross-linking degree of the adsorbent was tailored with the amount of acrylic acid which varied from 10wt% to 80wt%. Both Fourier transform infrared spectra and thermogravimetric analysis results verified the structure of the adsorbent. The maximum gel fraction and swelling ratio of the adsorbent were about 72% and 6.25, respectively, and they were able to be adjusted with the amount of monomers. The weight loss percentage of the adsorbent could reach 96.9% after immersing in the buffer solution that contained α-amylase for 14h. It was found that the adsorption capacities of the adsorbent for lead and mercury ions could be 123.2 and 131.2mg/g, respectively. In addition, the adsorbent was able to remove ca. 51-90% Pb(II) and Hg(II) ions that existed in the decoctions of four medicinal herbals. PMID:21724326

  19. Distribution of metal and adsorbed guest species in zeolites

    SciTech Connect

    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.

  20. Aminosilica materials as adsorbents for the selective removal of aldehydes and ketones from simulated bio-oil.

    PubMed

    Drese, Jeffrey H; Talley, Anne D; Jones, Christopher W

    2011-03-21

    The fast pyrolysis of biomass is a potential route to the production of liquid biorenewable fuel sources. However, degradation of the bio-oil mixtures due to reaction of oxygenates, such as aldehydes and ketones, reduces the stability of the liquids and can impact long-term storage and shipping. Herein, solid aminosilica adsorbents are described for the selective adsorptive removal of reactive aldehyde and ketone species. Three aminosilica adsorbents are prepared through the reaction of amine-containing silanes with pore-expanded mesoporous silica. A fourth aminosilica adsorbent is prepared through the ring-opening polymerization of aziridine from pore-expanded mesoporous silica. Adsorption experiments with a representative mixture of bio-oil model compounds are presented using each adsorbent at room temperature and 45 °C. The adsorbent comprising only primary amines adsorbs the largest amount of aldehydes and ketones. The overall reactivity of this adsorbent increases with increasing temperature. Additional aldehyde screening experiments show that the reactivity of aldehydes with aminosilicas varies depending on their chemical functionality. Initial attempts to regenerate an aminosilica adsorbent by acid hydrolysis show that they can be at least partially regenerated for further use. PMID:21246749

  1. Structural features of polymer adsorbent LiChrolut EN and interfacial behavior of water and water/organic mixtures.

    PubMed

    Gun'ko, V M; Turov, V V; Zarko, V I; Nychiporuk, Y M; Goncharuk, E V; Pakhlov, E M; Yurchenko, G R; Kulik, T V; Palyanytsya, B B; Borodavka, T V; Krupskaya, T V; Leboda, R; Skubiszewska-Zieba, J; Osovskii, V D; Ptushinskii, Y G; Turov, A V

    2008-07-01

    The structural and adsorption characteristics of polymer adsorbent LiChrolut EN and the behavior of adsorbed water and water/organic mixtures were studied using adsorption, microcalorimetry, transmission and scanning electron microscopy, mass spectrometry, infrared spectroscopy, 1H NMR spectroscopy with layer-by-layer freezing-out of liquids (190-273 K), and thermally stimulated depolarization current method (90-265 K). This adsorbent is characterized by large specific surface area (approximately 1500 m2/g) and pore volume (0.83 cm3/g) with a major contribution of narrow pores (R<10 nm) of a complicated shape (long hysteresis loop is in nitrogen adsorption-desorption isotherm). The adsorbent includes aromatic and aliphatic structures and oxygen-containing functionalities and can effectively adsorb organics and water/organic mixtures. On co-adsorption of water and organics (dimethyl sulfoxide, chloroform, methane), there is a weak influence of one on another adsorbate due to their poor mixing in pores. Weakly polar chloroform displaces a fraction of water from narrow pores. These effects can explain high efficiency of the adsorbent in solid-phase extraction of organics from aqueous solutions. The influence of structural features of several carbon and polymer adsorbents on adsorbed nitrogen, water and water/organics is compared on the basis of the adsorption and 1H NMR data. PMID:18440015

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

    SciTech Connect

    Zhu, Xiangdong.

    1989-08-01

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

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

    NASA Astrophysics Data System (ADS)

    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).

  4. Size selective hydrophobic adsorbent for organic molecules

    NASA Technical Reports Server (NTRS)

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

    1997-01-01

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

  5. Black Molecular Adsorber Coatings for Spaceflight Applications

    NASA Technical Reports Server (NTRS)

    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.

  6. Black molecular adsorber coatings for spaceflight applications

    NASA Astrophysics Data System (ADS)

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

    2014-09-01

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

  7. Method for modifying trigger level for adsorber regeneration

    DOEpatents

    Ruth, Michael J.; Cunningham, Michael J.

    2010-05-25

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

  8. Multicomponent adsorption of alcohols onto silicalite-1 from aqueous solution: isotherms, structural analysis, and assessment of ideal adsorbed solution theory.

    PubMed

    Bai, Peng; Tsapatsis, Michael; Siepmann, J Ilja

    2012-11-01

    Configurational-bias Monte Carlo (CBMC) simulations in the isobaric-isothermal version of the Gibbs ensemble (GE) were carried out to probe the adsorption from aqueous solutions of methanol and/or ethanol onto silicalite-1. This methodology does require neither specification of the chemical potential nor any reference to activity models based on experimental data. The CBMC-GE methodology can be applied to the complete range of mixture compositions from pure water to pure alcohols and can also be used when multiple solute types are present at high concentration. The simulations demonstrate high selectivities for the alcohols (α(ethanol) > α(methanol)) almost over the entire composition range. The ideal adsorbed solution theory is found to substantially underpredict the amount of sorbed water and leads to very large errors for low alcohol solution concentrations. The simulations indicate that, at lower loadings, the adsorbed alcohol molecules can serve as seeds for water adsorption but, at higher loadings, alcohols displace water molecules from their preferred region.

  9. Amine-pillared Nanosheet Adsorbents for CO2 Capture Applications

    NASA Astrophysics Data System (ADS)

    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

  10. Gaseous and adsorbed PAH in an iron foundry.

    PubMed Central

    Knecht, U; Elliehausen, H J; Woitowitz, H J

    1986-01-01

    The increased risk of lung cancer among foundry workers is assumed to be associated with the inhalation of gaseous and particle bound polycyclic aromatic hydrocarbons (PAH). These compounds are produced during pyrolysis of carbon containing loading material in the moulding sand. The concentrations of 20 PAH, some of which are carcinogenic, have been determined in the dusty casting area of an iron foundry by means of gas chromatography and mass spectrometry. The total dust was fractionated by means of a precision cascade impactor. It was possible to differentiate the PAH load in microgram/mg dust in seven particle size fractions ranging from 0.36- greater than or equal to 24.95 microns. Initially, there was an increase of the adsorbed PAH mass concentration with increasing particle diameter up to a maximum of 1.1 microgram/mg in the dust of the 1.57 micron fraction. Thereafter there was a continuous decrease of PAH mass concentration with increasing particle size. When the differing weights of the seven fractions are taken into account, however, the total PAH load of the individual fractions increases steadily with increasing particle size. The inhalable fine dust, 31.4% of the total dust, contains 49.9% of the total adsorbed PAH. The gas phase contained on average three times more carcinogenic PAH with four and five rings than was adsorbed on the dust. Thus the percentage of the gaseous substances amounts to 77% of the total PAH load at the place of work in an iron foundry. PMID:3801335

  11. Work function of alkali metal-adsorbed molybdenium dichalcogenides

    NASA Astrophysics Data System (ADS)

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

    NASA Astrophysics Data System (ADS)

    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. Activity of catalase adsorbed to carbon nanotubes: effects of carbon nanotube surface properties.

    PubMed

    Zhang, Chengdong; Luo, Shuiming; Chen, Wei

    2013-09-15

    Nanomaterials have been studied widely as the supporting materials for enzyme immobilization. However, the interactions between enzymes and carbon nanotubes (CNT) with different morphologies and surface functionalities may vary, hence influencing activities of the immobilized enzyme. To date how the adsorption mechanisms affect the activities of immobilized enzyme is not well understood. In this study the adsorption of catalase (CAT) on pristine single-walled carbon nanotubes (SWNT), oxidized single-walled carbon nanotubes (O-SWNT), and multi-walled carbon nanotubes (MWNT) was investigated. The adsorbed enzyme activities decreased in the order of O-SWNT>SWNT>MWNT. Fourier transforms infrared spectroscopy (FTIR) and circular dichrois (CD) analyses reveal more significant loss of α-helix and β-sheet of MWNT-adsorbed than SWNT-adsorbed CAT. The difference in enzyme activities between MWNT-adsorbed and SWNT-adsorbed CAT indicates that the curvature of surface plays an important role in the activity of immobilized enzyme. Interestingly, an increase of β-sheet content was observed for CAT adsorbed to O-SWNT. This is likely because as opposed to SWNT and MWNT, O-SWNT binds CAT largely via hydrogen bonding and such interaction allows the CAT molecule to maintain the rigidity of enzyme structure and thus the biological function.

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

    NASA Technical Reports Server (NTRS)

    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.

  15. Radon emanation from radium specific adsorbents.

    PubMed

    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.

  16. Unoccupied electronic states in adsorbate systems

    NASA Astrophysics Data System (ADS)

    Bertel, E.

    1991-11-01

    Experimental work on unoccupied electronic states in adsorbate systems on metallic substrates is reviewed with emphasis on recent developments. The first part is devoted to molecular adsorbates. Weakly chemisorbed hydrocarbons are briefly discussed. An exhaustive inverse photoemission (IPE) study of the CO bond to the transition metals Ni, Pb, and Pt is presented. Adsorbed NO is taken as an example to demonstrate the persisting discrepancies in the interpretation of IPE spectra. Atomic adsorbates are discussed in the second part. The quantum well state model is applied to interpret the surface states in reconstructing and non-reconstructing adsorption systems of alkali metals and hydrogen. A recent controversy on the unoccupied electronic states of the Cu(110)/O p(2×1) surface is critically reviewed. The quantum well state model is then compared to tight binding and local-density-functional calculations of the unoccupied bands and the deficiencies of the various approaches are pointed out. Finally, the relation between the surface state model and more chemically oriented models of surface bonding is briefly discussed.

  17. Continuum elastic theory of adsorbate vibrational relaxation

    NASA Astrophysics Data System (ADS)

    Lewis, Steven P.; Pykhtin, M. V.; Mele, E. J.; Rappe, Andrew M.

    1998-01-01

    An analytical theory is presented for the damping of low-frequency adsorbate vibrations via resonant coupling to the substrate phonons. The system is treated classically, with the substrate modeled as a semi-infinite elastic continuum and the adsorbate overlayer modeled as an array of point masses connected to the surface by harmonic springs. The theory provides a simple expression for the relaxation rate in terms of fundamental parameters of the system: γ=mω¯02/AcρcT, where m is the adsorbate mass, ω¯0 is the measured frequency, Ac is the overlayer unit-cell area, and ρ and cT are the substrate mass density and transverse speed of sound, respectively. This expression is strongly coverage dependent, and predicts relaxation rates in excellent quantitative agreement with available experiments. For a half-monolayer of carbon monoxide on the copper (100) surface, the predicted damping rate of in-plane frustrated translations is 0.50×1012s-1, as compared to the experimental value of (0.43±0.07)×1012s-1. Furthermore it is shown that, for all coverages presently accessible to experiment, adsorbate motions exhibit collective effects which cannot be treated as stemming from isolated oscillators.

  18. Synthesis of novel aminated cellulose microsphere adsorbent for efficient Cr(VI) removal

    NASA Astrophysics Data System (ADS)

    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.

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

    NASA Astrophysics Data System (ADS)

    ćiçek, Ekrem; Dede, Bülent

    2013-12-01

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

  20. Development and Testing of Molecular Adsorber Coatings

    NASA Technical Reports Server (NTRS)

    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. Structure of polymer layers adsorbed from concentrated solutions

    NASA Astrophysics Data System (ADS)

    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

  2. In Situ Investigation the Photolysis of the PAHs Adsorbed on Mangrove Leaf Surfaces by Synchronous Solid Surface Fluorimetry

    PubMed Central

    Wang, Ping; Wu, Tun-Hua; Zhang, Yong

    2014-01-01

    An established synchronous solid surface fluorimetry (S-SSF) was utilized for in situ study the photolysis processes of anthracene (An) and pyrene (Py) adsorbed on the leaf surfaces of Kandelia obovata seedlings (Ko) and Aegiceras corniculata (L.) Blanco seedlings (Ac). Experimental results demonstrated that the photolysis of An and Py adsorbed on the leaf surfaces of two mangrove species under the laboratory conditions, followed first-order kinetics with their photolysis rates in the order of Ac>Ko. In addition, with the same amount of substances, the photolysis rate of An adsorbed on the same mangrove leaf surfaces was much faster than the adsorbed Py. In order to investigate further, the photolysis processes of An and Py in water were also studied for comparison. And the photolysis of An and Py in water also followed first-order kinetics. Moreover, for the same initial amount, the photolysis rate of the PAH in water was faster than that adsorbed on the leaf surfaces of two mangrove species. Therefore, photochemical behaviors of PAHs were dependent not only on their molecular structures but also the physical-chemical properties of the substrates on which they are adsorbed. PMID:24404158

  3. 20 CFR 228.52 - Restored amount.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 20 Employees' Benefits 1 2010-04-01 2010-04-01 false Restored amount. 228.52 Section 228.52... SURVIVOR ANNUITIES The Tier II Annuity Component § 228.52 Restored amount. (a) General. A restored amount...(er) had ten years of creditable railroad service prior to January 1, 1975. (b) Amount. The amount...

  4. 20 CFR 228.52 - Restored amount.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 20 Employees' Benefits 1 2011-04-01 2011-04-01 false Restored amount. 228.52 Section 228.52... SURVIVOR ANNUITIES The Tier II Annuity Component § 228.52 Restored amount. (a) General. A restored amount...(er) had ten years of creditable railroad service prior to January 1, 1975. (b) Amount. The amount...

  5. Mobilization of arsenite by dissimilatory reduction of adsorbed arsenate

    USGS Publications Warehouse

    Zobrist, J.; Dowdle, P.R.; Davis, J.A.; Oremland, R.S.

    2000-01-01

    Sulfurospirillum barnesii is capable of anaerobic growth using ferric iron or arsenate as electron acceptors. Cell suspensions of S. barnesii were able to reduce arsenate to arsenite when the former oxyanion was dissolved in solution, or when it was adsorbed onto the surface of ferrihydrite, a common soil mineral, by a variety of mechanisms (e.g., coprecipitation, presorption). Reduction of Fe(III) in ferrihydrite to soluble Fe(II) also occurred, but dissolution of ferrihydrite was not required in order for adsorbed arsenate reduction to be achieved. This was illustrated by bacterial reduction of arsenate coprecipitated with aluminum hydroxide, a mineral that does not undergo reductive dissolution. The rate of arsenate reduction was influenced by the method in which arsenate became associated with the mineral phases and may have been strongly coupled with arsenate desorption rates. The extent of release of arsenite into solution was governed by adsorption of arsenite onto the ferrihydrite or alumina phases. The results of these experiments have interpretive significance to the mobilization of arsenic in large alluvial aquifers, such as those of the Ganges in India and Bangladesh, and in the hyporheic zones of contaminated streams.Sulfurospirillum barnesii is capable of anaerobic growth using ferric iron or arsenate as electron acceptors. Cell suspensions of S. barnesii were able to reduce arsenate to arsenite when the former oxyanion was dissolved in solution, or when it was adsorbed onto the surface of ferrihydrite a common soil mineral, by a variety of mechanisms (e.g., coprecipitation, presorption). Reduction of Fe(III) in ferrihydrite to soluble Fe(II) also occurred, but dissolution of ferrihydrite was not required in order for adsorbed arsenate reduction to be achieved. This was illustrated by bacterial reduction of arsenate coprecipitated with aluminum hydroxide, a mineral that does not undergo reductive dissolution. The rate of arsenate reduction was

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

    NASA Astrophysics Data System (ADS)

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

    2016-09-01

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

  7. Natural Transformation of Azotobacter vinelandii by Adsorbed Chromosomal DNA: Role of Adsorbed DNA Conformation

    NASA Astrophysics Data System (ADS)

    Lv, N.; Zilles, J.; Nguyen, H.

    2008-12-01

    Recent increases in antibiotic resistance among pathogenic microorganisms and the accompanying public health concerns result both from the widespread use of antibiotics and from the transfer of antibiotic resistance genes among microorganisms. To understand the transfer of antibiotic resistance genes and identify efficient measures to minimize these transfers, an interdisciplinary approach was used to identify physical and chemical factors that control the fate and biological availability of extracellular DNA. Quartz crystal microbalance with dissipation (QCM-D) was used to study extracellular DNA adsorption and the conformation of the adsorbed DNA on silica and natural organic matter (NOM) surfaces. Solution chemistry was varied systematically to investigate the role of adsorbed DNA conformation on transformation. Gene transfer was assessed under the same conditions using natural transformation of chromosomal DNA into the soil bacteria Azotobacter vinelandii. DNA adsorbed to both silica and NOM surfaces has a more compact and rigid conformation in the presence of Ca2+ compared to Na+. Extracellular DNA adsorbed on silica and NOM surfaces transformed A. vinelandii. The transformation efficiency of adsorbed DNA was up to 4 orders of magnitude lower than that of dissolved DNA. Preliminary results suggest that the presence of Ca2+ in groundwater (e.g. hardness) reduces the availability of adsorbed DNA for transformation.

  8. EMERGING TECHNOLOGY SUMMARY: DEMONSTRATION OF AMBERSORB 563 ADSORBENT TECHNOLOGY

    EPA Science Inventory

    A field pilot study was conducted to demonstrate the technical feasibility and cost-effectiveness of Ambersorb® 5631 carbonaceous adsorbent for remediating groundwater contaminated with volatile organic compounds (VOCs). The Ambersorb adsorbent technology demonstration consist...

  9. Activated carbon prepared from coffee pulp: potential adsorbent of organic contaminants in aqueous solution.

    PubMed

    Gonçalves, Maraisa; Guerreiro, Mário César; Ramos, Paulize Honorato; de Oliveira, Luiz Carlos Alves; Sapag, Karim

    2013-01-01

    The processing of coffee beans generates large amounts of solid and liquid residues. The solid residues (pulp, husk and parchment) represent a serious environmental problem and do not have an adequate disposal mechanism. In this work, activated carbons (ACs) for adsorption of organic compounds were prepared from coffee pulp by controlled temperature at different pulp/Na2HPO4 ratios (4:1, 2:1, 5:4 and 1:1). The N2 adsorption/desorption isotherms showed ACs with high quantities of mesopores and micropores and specific surface areas of 140, 150, 450 and 440 m(2)g(-1) for AC 4:1, AC 2:1, AC 5:4 and AC 1:1, respectively. The prepared material AC 5:4 showed a higher removal capacity of the organic contaminants methylene blue (MB), direct red (DR) and phenol than did a Merck AC. The maximum capacities for this AC are approximately 150, 120 and 120 mg g(-1) for MB, DR and phenol, respectively. Thus, a good adsorbent was obtained from coffee pulp, an abundant Brazilian residue.

  10. Computer simulations of adsorbed liquid crystal films

    NASA Astrophysics Data System (ADS)

    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.

  11. Gas storage using fullerene based adsorbents

    NASA Technical Reports Server (NTRS)

    Loutfy, Raouf O. (Inventor); Lu, Xiao-Chun (Inventor); Li, Weijiong (Inventor); Mikhael, Michael G. (Inventor)

    2000-01-01

    This invention is directed to the synthesis of high bulk density high gas absorption capacity adsorbents for gas storage applications. Specifically, this invention is concerned with novel gas absorbents with high gravimetric and volumetric gas adsorption capacities which are made from fullerene-based materials. By pressing fullerene powder into pellet form using a conventional press, then polymerizing it by subjecting the fullerene to high temperature and high inert gas pressure, the resulting fullerene-based materials have high bulk densities and high gas adsorption capacities. By pre-chemical modification or post-polymerization activation processes, the gas adsorption capacities of the fullerene-based adsorbents can be further enhanced. These materials are suitable for low pressure gas storage applications, such as oxygen storage for home oxygen therapy uses or on-board vehicle natural gas storage. They are also suitable for storing gases and vapors such as hydrogen, nitrogen, carbon dioxide, and water vapor.

  12. Aquaculture of Uranium in Seawater by a Fabric-Adsorbent Submerged System

    SciTech Connect

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

    2003-11-15

    The total amount of uranium dissolved in seawater at a uniform concentration of 3 mg U/m{sup 3} in the world's oceans is 4.5 billion tons. An adsorption method using polymeric adsorbents capable of specifically recovering uranium from seawater is reported to be economically feasible. A uranium-specific nonwoven fabric was used as the adsorbent packed in an adsorption cage 16 m{sup 2} in cross-sectional area and 16 cm in height. We submerged three adsorption cages in the Pacific Ocean at a depth of 20 m at 7 km offshore of Japan. The three adsorption cages consisted of stacks of 52 000 sheets of the uranium-specific non-woven fabric with a total mass of 350 kg. The total amount of uranium recovered by the nonwoven fabric was >1 kg in terms of yellow cake during a total submersion time of 240 days in the ocean.

  13. Ottawa moves to decriminalize small amounts of marijuana.

    PubMed

    Thaczuk, Derek

    2003-08-01

    Making good on a promise made in December 2002, the federal government has tabled a bill that would decriminalize possession of small amounts of marijuana. However, the bill would also toughen penalties for growing large amounts. The bill is part of a renewed Canada Drug Strategy that emphasizes the need to discourage cannabis use. PMID:14746294

  14. Orbital tomography for highly symmetric adsorbate systems

    NASA Astrophysics Data System (ADS)

    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.

  15. [Melting in adsorbed films]. Progress report 1992

    SciTech Connect

    Simon, M.I.

    1992-12-31

    Over the past several years we have been developing a new approach to cloning large fragments of mammalian DNA in E. coli. which will permit detailed analysis of complex genomes. In January 1992 we began construction of an arrayed total human genomic library prepared in our BAC vector. Our goal is to create a 4-5X library which will be accessible for screening both by colony hybridization and by PCR. Our efforts in 1992 have been focused on expanding this library, characterizing specific clones isolated from the library, and demonstrating the use of BACs and Fosmids in creating physical maps. As a Model for the use of BACs in physical mapping, we have begun mapping human chromosome 22. In addition to their stability and ease of handling, BACs and Fosniids offer the advantage of permitting isolation of relatively large amounts of pure DNA which should greatly facilitate contig construction. We have created a 7X chromosome 22-specific Fosmid library consisting of clones obtained from DNA from a hybrid cell line.

  16. Selective Response of Mesoporous Silicon to Adsorbants with Nitro Groups

    SciTech Connect

    McLeod, John A.; Kurmaev, Ernst Z.; Sushko, Petr V.; Boyko, Teak D.; Levitsky, Igor A.; Moewes, Alexander

    2012-01-30

    We demonstrate that the electronic structure of mesoporous silicon is affected by adsorption of nitrobased explosive molecules in a compound-selective manner. This selective response is demonstrated by probing the adsorption of two nitro-based molecular explosives (trinitrotoluene and cyclotrimethylenetrinitramine) and a nonexplosive nitro-based aromatic molecule (nitrotoluene) on mesoporous silicon using soft X-ray spectroscopy. The Si atoms strongly interact with adsorbed molecules to form Si-O and Si-N bonds, as evident from the large shifts in emission energy present in the Si L2,3 X-ray emission spectroscopy (XES) measurements. Furthermore, we find that the energy gap (band gap) of mesoporous silicon changes depending on the adsorbant, as estimated from the Si L2,3 XES and 2p X-ray absorption spectroscopy (XAS) measurements. Our ab initio molecular dynamics calculations of model compounds suggest that these changes are due to spontaneous breaking of the nitro groups upon contacting surface Si atoms. This compound-selective change in electronic structure may provide a powerful tool for the detection and identification of trace quantities of airborne explosive molecules.

  17. Fluctuations of surface-enhanced Raman spectra of CO adsorbed on gold substrates

    NASA Astrophysics Data System (ADS)

    Kudelski, Andrzej; Pettinger, Bruno

    2004-01-01

    Surface-enhanced Raman scattering (SERS) of CO adsorbed on roughened gold surfaces has been studied using a Raman microscope with high spatial resolution. Sequentially recorded SERS spectra showed variations of Raman lines in their number, intensity, frequency, and halfwidth. Sometimes, in addition to the band for CO adsorbed at top sites, Raman peaks for bridge-bonded CO appear, showing large intensity fluctuations. Obviously, SERS fluctuations represent a more general property of SERS and point to local restructuring of substrates that changes temporarily the character of adsorption sites and/or their contribution to SERS. The single molecule 'blinking' effect is also discussed.

  18. Epoxide-functionalization of polyethyleneimine for synthesis of stable carbon dioxide adsorbent in temperature swing adsorption.

    PubMed

    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

  19. Characterization of production of free gluconic acid by Gluconobacter suboxydans adsorbed on ceramic honeycomb monolith.

    PubMed

    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. Epoxide-functionalization of polyethyleneimine for synthesis of stable carbon dioxide adsorbent in temperature swing adsorption

    NASA Astrophysics Data System (ADS)

    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.

  1. Epoxide-functionalization of polyethyleneimine for synthesis of stable carbon dioxide adsorbent in temperature swing adsorption.

    PubMed

    Choi, Woosung; Min, Kyungmin; Kim, Chaehoon; Ko, Young Soo; Jeon, Jae Wan; Seo, Hwimin; Park, Yong-Ki; Choi, Minkee

    2016-08-30

    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.

  2. Epoxide-functionalization of polyethyleneimine for synthesis of stable carbon dioxide adsorbent in temperature swing adsorption

    PubMed Central

    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

  3. Development and characterization of activated hydrochars from orange peels as potential adsorbents for emerging organic contaminants.

    PubMed

    Fernandez, M E; Ledesma, B; Román, S; Bonelli, P R; Cukierman, A L

    2015-05-01

    Activated hydrochars obtained from the hydrothermal carbonization of orange peels (Citrus sinensis) followed by various thermochemical processing were assessed as adsorbents for emerging contaminants in water. Thermal activation under flows of CO2 or air as well as chemical activation with phosphoric acid were applied to the hydrochars. Their characteristics were analyzed and related to their ability to uptake three pharmaceuticals (diclofenac sodium, salicylic acid and flurbiprofen) considered as emerging contaminants. The hydrothermal carbonization and subsequent activations promoted substantial chemical transformations which affected the surface properties of the activated hydrochars; they exhibited specific surface areas ranging from 300 to ∼620 m(2)/g. Morphological characterization showed the development of coral-like microspheres dominating the surface of most hydrochars. Their ability to adsorb the three pharmaceuticals selected was found largely dependent on whether the molecules were ionized or in their neutral form and on the porosity developed by the new adsorbents. PMID:25742754

  4. Novel surfactant-based adsorbent material for groundwater remediation.

    PubMed

    Venditti, F; Angelico, R; Ceglie, A; Ambrosone, L

    2007-10-01

    Many surfactants aggregate spontaneously in aqueous media to form small spherical structures called micelles. Among the numerous technical applications it is known that micelles have the ability to dissolve in their hydrophobic part significant amounts of water-insoluble organic compounds. In this study we investigated through UV-vis spectroscopy the micellar solubilization of 2,4,5-trichlorophenol (Tcp), an intermediate product of the microbial degradation of the broad-leaf herbicide 2,4,5-trichlorophenoxyacetic (2,4,5-T). Our results show that in the presence of the anionic surfactant sodium dodecylsulfate SDS the water solubility of Tcp increases six-fold whereas with cationic CTAB and nonionic Triton-X 100 the partition of chlorinated compound is not efficient. After the excess amount of the pollutant solubilized in SDS-micelles has been precipitated with CaCl2 the remaining fraction of Tcp has been successfully reduced within the toxicological limit for drinkable water through a cocurrent multistage operation. Finally, potential use in the decontamination of wastewater or soils of the new adsorbent material has been compared with the most commonly used activated carbon and silica gel.

  5. Reduced colloidal repulsion imparted by adsorbed polymer of particle dimensions.

    PubMed

    Wen, Yu Ho; Lin, Po-Chang; Lee, Chun Yi; Hua, Chi Chung; Lee, Tai-Chou

    2010-09-01

    This work investigated the detailed interparticle interactions in a concentrated polymer-coated colloidal system in which the bare colloidal particles and the adsorbed polymers are of comparable size and, hence, the polymer adsorption cannot be foreseen to induce repulsive or attractive interactions. Specifically, poly(ethylene oxide) (PEO) chains (R(g) approximately 10nm) adsorbed onto fine silica colloidal particles (SAXS-determined radius approximately 7.4nm; width of log-normal size distribution approximately 0.28) were considered as a model system, for which the impact of a small amount of polymer adsorption (0.18mg/m(2)) in controlling the interactions of the PEO-coated silica particles was systematically explored by analyzing the small-angle X-ray scattering (SAXS) data against three interaction potentials-the equivalent hard-sphere (EHS) potential, the Hayter-Penfold-Yukawa (HPY) potential, and the square-well (SW) potential. Moreover, the SAXS analysis was enforced by dynamic light scattering (DLS) for predetermining the adsorption behavior, as well as for evaluating the possibility of polymer bridging. Under a dilute condition, the DLS analysis showed no sign of forming colloidal multiplets. In concentrated dispersions, both the HPY and SW potentials clearly revealed a systematic decrease of colloidal repulsions with increased PEO coverage, ascribed to a partially "screened" electrostatic interaction and/or the formation of PEO-bridged silica doublets. The present findings have interesting implications for controlling the colloidal interactions and microstructures of fine polymer-coated particles in dense or condensed phases.

  6. 20 CFR 228.51 - Takeback amount.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 20 Employees' Benefits 1 2010-04-01 2010-04-01 false Takeback amount. 228.51 Section 228.51... SURVIVOR ANNUITIES The Tier II Annuity Component § 228.51 Takeback amount. (a) The 1983 amendments to the... annuity component be offset from the amount of the tier II annuity. This amount is the takeback...

  7. 20 CFR 340.2 - Amount recoverable.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 20 Employees' Benefits 1 2011-04-01 2011-04-01 false Amount recoverable. 340.2 Section 340.2... RECOVERY OF BENEFITS § 340.2 Amount recoverable. For purposes of this part, an “amount recoverable” is an amount of unemployment, sickness, or maternity benefits paid under the Railroad Unemployment...

  8. 14 CFR 1300.13 - Guarantee amount.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 14 Aeronautics and Space 5 2011-01-01 2010-01-01 true Guarantee amount. 1300.13 Section 1300.13....13 Guarantee amount. (a) Under Section 101(a)(1) of the Act, the Board is authorized to enter into... loan amount guaranteed to a single air carrier may not exceed that amount that, in the Board's...

  9. 27 CFR 70.243 - Exempt amount.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 27 Alcohol, Tobacco Products and Firearms 2 2011-04-01 2011-04-01 false Exempt amount. 70.243... Excise and Special (Occupational) Tax Limitations § 70.243 Exempt amount. Amount payable to the taxpayer... exempt from levy as follows: (a) If the payroll period is weekly, an amount equal to: (1) The sum of:...

  10. 13 CFR 120.930 - Amount.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 13 Business Credit and Assistance 1 2011-01-01 2011-01-01 false Amount. 120.930 Section 120.930... Program (504) 504 Loans and Debentures § 120.930 Amount. (a) Generally, a 504 loan may not exceed 40..., the Debenture amount will be reduced by the amount that the unused contingency reserve exceeds...

  11. 13 CFR 120.930 - Amount.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 13 Business Credit and Assistance 1 2010-01-01 2010-01-01 false Amount. 120.930 Section 120.930... Program (504) 504 Loans and Debentures § 120.930 Amount. (a) Generally, a 504 loan may not exceed 40..., the Debenture amount will be reduced by the amount that the unused contingency reserve exceeds...

  12. 27 CFR 70.243 - Exempt amount.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 27 Alcohol, Tobacco Products and Firearms 2 2010-04-01 2010-04-01 false Exempt amount. 70.243... Excise and Special (Occupational) Tax Limitations § 70.243 Exempt amount. Amount payable to the taxpayer... exempt from levy as follows: (a) If the payroll period is weekly, an amount equal to: (1) The sum of:...

  13. 24 CFR 594.15 - Allocation amounts.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 24 Housing and Urban Development 3 2011-04-01 2010-04-01 true Allocation amounts. 594.15 Section... § 594.15 Allocation amounts. (a) Amounts and match requirement. HUD will make grants, in the form of... for less than the maximum amount established by statute, and to limit the number of times a...

  14. 20 CFR 228.51 - Takeback amount.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 20 Employees' Benefits 1 2011-04-01 2011-04-01 false Takeback amount. 228.51 Section 228.51... SURVIVOR ANNUITIES The Tier II Annuity Component § 228.51 Takeback amount. (a) The 1983 amendments to the... annuity component be offset from the amount of the tier II annuity. This amount is the takeback...

  15. 46 CFR Sec. 2 - Amount of bond.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 46 Shipping 8 2014-10-01 2014-10-01 false Amount of bond. Sec. 2 Section 2 Shipping MARITIME ADMINISTRATION, DEPARTMENT OF TRANSPORTATION A-NATIONAL SHIPPING AUTHORITY BONDING OF SHIP'S PERSONNEL Sec. 2 Amount of bond. The amount of the bond must be governed by the amount of monies advanced or value of...

  16. 46 CFR Sec. 2 - Amount of bond.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 46 Shipping 8 2013-10-01 2013-10-01 false Amount of bond. Sec. 2 Section 2 Shipping MARITIME ADMINISTRATION, DEPARTMENT OF TRANSPORTATION A-NATIONAL SHIPPING AUTHORITY BONDING OF SHIP'S PERSONNEL Sec. 2 Amount of bond. The amount of the bond must be governed by the amount of monies advanced or value of...

  17. 46 CFR Sec. 2 - Amount of bond.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 46 Shipping 8 2011-10-01 2011-10-01 false Amount of bond. Sec. 2 Section 2 Shipping MARITIME ADMINISTRATION, DEPARTMENT OF TRANSPORTATION A-NATIONAL SHIPPING AUTHORITY BONDING OF SHIP'S PERSONNEL Sec. 2 Amount of bond. The amount of the bond must be governed by the amount of monies advanced or value of...

  18. 46 CFR Sec. 2 - Amount of bond.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 46 Shipping 8 2012-10-01 2012-10-01 false Amount of bond. Sec. 2 Section 2 Shipping MARITIME ADMINISTRATION, DEPARTMENT OF TRANSPORTATION A-NATIONAL SHIPPING AUTHORITY BONDING OF SHIP'S PERSONNEL Sec. 2 Amount of bond. The amount of the bond must be governed by the amount of monies advanced or value of...

  19. 46 CFR Sec. 2 - Amount of bond.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 46 Shipping 8 2010-10-01 2010-10-01 false Amount of bond. Sec. 2 Section 2 Shipping MARITIME ADMINISTRATION, DEPARTMENT OF TRANSPORTATION A-NATIONAL SHIPPING AUTHORITY BONDING OF SHIP'S PERSONNEL Sec. 2 Amount of bond. The amount of the bond must be governed by the amount of monies advanced or value of...

  20. Adsorbent capability testing using desorption efficiency method on palm oil fiber

    NASA Astrophysics Data System (ADS)

    Manap, Nor Rahafza Abdul; Shamsudin, Roslinda

    2015-09-01

    The palm oil fiber had been used as filler in making thermoplastics, biocomposites and also used as adsorbent in treating waste water. In this study, palm oil fiber was used as adsorbent to treat indoor air pollutants that caused by toluene, ethylbenzene, ortho-, meta-, and para- xylene (o-, m-, p-xylene). Known amount of pollutants, ranges between 1.3 to 28 ppm was spiked into palm oil fiber and left in refrigerator for 24 hours. Then, elution of the pollutants was carried out by carbon disulphide as mobile phase or eluent. The ability of palm oil fiber as adsorbent was determine using desorption efficiency technique by gas chromatography with flame ionization detector (GC/FID). The desorption efficiency percentage given by toluene was in the range of 88.9% to 100%, 91% to 100% for ethylbenzene, 65% to 100% for pm-xylene and 92.9% to 100% for o-xylene. This percentage indicates that palm oil fiber can be used as adsorbent to treat indoor air pollutants.

  1. Configuration of bovine serum albumin adsorbed on polymer particles with grafted dextran corona.

    PubMed

    Vauthier, Christine; Lindner, Peter; Cabane, Bernard

    2009-03-01

    The configuration of BSA macromolecules adsorbed on the surfaces of poly(alkylcyanoacrylate) nanoparticles has been determined using small angle neutron scattering (SANS). The nanoparticles were made by anionic emulsion polymerization (AEP) and self-assembly of dextran-poly(isobutylcyanoacrylate) (PICBA) copolymers. They have a hydrophobic PICBA core and a hydrophilic dextran corona. In vivo, they are recognized by the macrophages of the mononuclear phagocyte system. The amount of BSA bound to the particles, at adsorption equilibrium, has been determined through immunodiffusion, immunoelectrophoresis, and SANS. For particles with a radius of 25.3nm, the adsorption was found to saturate at 64 adsorbed BSA molecules per particle. The configuration of the adsorbed BSA molecules was determined from the SANS scattering curves, first at full contrast, and then at contrast match. Both experiments indicate that the BSA molecules are adsorbed on the PICBA core, in a flat configuration. This result may be important for understanding the in vivo opsonization mechanisms of nanoparticles and their resulting biodistribution.

  2. Photoacoustic spectroscopy of surface adsorbed molecules using a nanostructured coupled resonator array

    NASA Astrophysics Data System (ADS)

    Lee, Dongkyu; Kim, Seonghwan; Van Neste, C. W.; Lee, Moonchan; Jeon, Sangmin; Thundat, Thomas

    2014-01-01

    A rapid method of obtaining photoacoustic spectroscopic signals for trace amounts of surface adsorbed molecules using a nanostructured coupled resonator array is described. Explosive molecules adsorbed on a nanoporous anodic aluminum oxide cantilever, which has hexagonally ordered nanowells with diameters and well-to-well distances of 35 nm and 100 nm, respectively, are excited using pulsed infrared (IR) light with a frequency matching the common mode resonance frequency of the coupled resonator. The common mode resonance amplitudes of the coupled resonator as a function of illuminating IR wavelength present a photoacoustic IR absorption spectrum representing the chemical signatures of the adsorbed explosive molecules. In addition, the mass of the adsorbed molecules as an orthogonal signal for quantitative analysis is determined by measuring the variation of the localized, individual mode resonance frequency of a cantilever on the array. The limit of detection of the ternary mixture of explosive molecules (1:1:1 of trinitrotoluene (TNT), cyclotrimethylene trinitramine (RDX) and pentaerythritol tetranitrate (PETN)) is estimated to be ˜100 ng cm-2. These multi-modal signals enable us to perform quantitative and rapid chemical sensing and analysis in ambient conditions.

  3. Al-doped graphene as a new nanostructure adsorbent for some halomethane compounds: DFT calculations

    NASA Astrophysics Data System (ADS)

    Rad, Ali Shokuhi

    2016-03-01

    We have studied the electronic structure and property of pristine as well as Al-doped graphene sheets towards adsorption of some halomethane compounds (trichloromethane, dichloromethane, and difluoromethane) using density functional theory (DFhsT) calculations. The adsorption energies have been calculated for each adsorbed-adsorbent system. Based on our results, compared to pristine graphene, the Al-doped graphene causes significant adsorption energy, higher charge transferring, and smaller bond distances to halomethane compounds. Our calculated adsorption energies of trichloromethane, dichloromethane, and difluoromethane on Al-doped graphene were - 54.1, - 68.3, and - 123.2 kJ mol- 1, respectively, which are categorized in the chemisorption region while the adsorption of these molecules on pristine graphene release insignificant energies which correspond to very weak adsorption on it. Furthermore, we used charge transfer analysis to search the amount of electron allocation. Orbital analysis including the density of states (DOS) was done to find the possible orbital hybridization between adsorbates and two graphene sheets. These results imply the suitability of Al-doped graphene as a good adsorbent/sensor for halomethane compounds.

  4. Carbonised jackfruit peel as an adsorbent for the removal of Cd(II) from aqueous solution.

    PubMed

    Inbaraj, B Stephen; Sulochana, N

    2004-08-01

    The fruit of the jack (Artocarpus heterophyllus) is one of the popular fruits in India, where the total area under this fruit is about 13,460 ha. A significant amount of peel (approximately 2,714-11,800 kg per tree per year) is discarded as agricultural waste, as apart from its use as a table fruit, it is popular in many culinary preparations. Treatment of jackfruit peel with sulphuric acid produced a carbonaceous product which was used to study its efficiency as an adsorbent for the removal of Cd(II) from aqueous solution. Batch experiments were performed as a function of process parameters; agitation time, initial metal concentration, adsorbent concentration and pH. Kinetic analyses made with Lagergren pseudo-first-order, Ritchie second-order and modified Ritchie second-order models showed better fits with modified Ritchie second-order model. The Langmuir-Freundlich (Sips equation) model best defined the experimental equilibrium data among the three isotherm models (Freundlich, Langmuir and Langmuir-Freundlich) tested. Taking a particular metal concentration, the optimum dose and pH required for the maximum metal removal was established. A complete recovery of the adsorbed metal ions from the spent adsorbent was achieved by using 0.01 M HCl.

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

    NASA Astrophysics Data System (ADS)

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

    2015-12-01

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

  6. Effect of Polarity of Activated Carbon Surface, Solvent and Adsorbate on Adsorption of Aromatic Compounds from Liquid Phase.

    PubMed

    Goto, Tatsuru; Amano, Yoshimasa; Machida, Motoi; Imazeki, Fumio

    2015-01-01

    In this study, introduction of acidic functional groups onto a carbon surface and their removal were carried out through two oxidation methods and outgassing to investigate the adsorption mechanism of aromatic compounds which have different polarity (benzene and nitrobenzene). Adsorption experiments for these aromatics in aqueous solution and n-hexane solution were conducted in order to obtain the adsorption isotherms for commercial activated carbon (BAC) as a starting material, its two types of oxidized BAC samples (OXs), and their outgassed samples at 900 °C (OGs). Adsorption and desorption kinetics of nitrobenzene for the BAC, OXs and OGs in aqueous solution were also examined. The results showed that the adsorption of benzene molecules was significantly hindered by abundant acidic functional groups in aqueous solution, whereas the adsorbed amount of nitrobenzene on OXs gradually increased as the solution concentration increased, indicating that nitrobenzene can adsorb favourably on a hydrophilic surface due to its high dipole moment, in contrast to benzene. In n-hexane solution, it was difficult for benzene to adsorb on any sample owing to the high affinity between benzene and n-hexane solvent. On the other hand, adsorbed amounts of nitrobenzene on OXs were larger than those of OGs in n-hexane solution, implying that nitrobenzene can adsorb two adsorption sites, graphene layers and surface acidic functional groups. The observed adsorption and desorption rate constants of nitrobenzene on the OXs were lower than those on the BAC due to disturbance of diffusion by the acidic functional groups.

  7. Recovery of Technetium Adsorbed on Charcoal

    SciTech Connect

    Engelmann, Mark D.; Metz, Lori A.; Ballou, Nathan E.

    2006-05-01

    Two methods capable of near complete recovery of technetium adsorbed on charcoal are presented. The first involves liquid extraction of the technetium from the charcoal by hot 4M nitric acid. An average recovery of 98% (n=3) is obtained after three rounds of extraction. The second method involves dry ashing with air in a quartz combustion tube at 400-450 C. This method yields an average recovery of 96% (n=5). Other thermal methods were attempted, but resulted in reduced recovery and incomplete material balance

  8. Conformational properties of an adsorbed charged polymer.

    PubMed

    Cheng, Chi-Ho; Lai, Pik-Yin

    2005-06-01

    The behavior of a strongly charged polymer adsorbed on an oppositely charged surface of a low-dielectric constant is formulated by the functional integral method. By separating the translational, conformational, and fluctuational degrees of freedom, the scaling behaviors for both the height of the polymer and the thickness of the diffusion layer are determined. Unlike the results predicted by scaling theory, we identified the continuous crossover from the weak compression to the compression regime. All the analytical results are found to be consistent with Monte Carlo simulations. Finally, an alternative (operational) definition of a charged polymer adsorption is proposed. PMID:16089715

  9. Radiation synthesis of a new amidoximated UHMWPE fibrous adsorbent with high adsorption selectivity for uranium over vanadium in simulated seawater

    NASA Astrophysics Data System (ADS)

    Gao, Qianhong; Hu, Jiangtao; Li, Rong; Xing, Zhe; Xu, Lu; Wang, Mouhua; Guo, Xiaojing; Wu, Guozhong

    2016-05-01

    A new kind of highly efficient adsorbent material has been fabricated in this study for the purpose of extracting uranium from seawater. Ultra-high molecular weight polyethylene (UHMWPE) fiber was used as a trunk material for the adsorbent, which was prepared by a series of modification reactions, as follows: (1) grafting of glycidyl methacrylate (GMA) and methyl acrylate (MA) onto UHMWPE fibers via 60Co γ-ray pre-irradiation; (2) aminolyzation of UHMWPE fiber by the ring-opening reaction between of epoxy groups PGMA and ethylene diamine (EDA); (3) Michael addition of amino groups with acrylonitrile (AN) to yield nitrile groups; (4) amidoximation of the attached nitrile moieties by hydroxylamine in dimethyl sulfoxide-water mixture. Modified UHMWPE fibers were characterized by means of attenuated total reflectance-Fourier transformed infrared spectroscopy (ATR-FTIR), thermogravimetric analysis (TGA) and scanning electron microscopy (SEM) to confirm the attachment of amidoxime (AO) groups onto the UHMWPE fibers. The results of X-ray diffraction (XRD) and single fiber tensile strength verified that the modified UHMWPE fiber retained excellent mechanical properties at a low absorbed radiation dose. The adsorption performance of the UHMWPE fibrous adsorbent was evaluated by subjecting it to an adsorption test in simulated seawater using a continuous-flow mode. The amount of uranium adsorbed by this AO-based UHMWPE fibrous adsorbent was 1.97 mg-U/g after 42 days. This new adsorbent also showed high selectivity for the uranyl ion, and its selectivity for metal ions was found to decrease in the following order: U>Cu>Fe>Ca>Mg>Ni>Zn>Pb>V>Co. The adsorption selectivity for uranium is significantly higher than that for vanadium. In addition, preparation of this modified adsorbent consumes much smaller amounts of the toxic acrylonitrile monomer than the conventional preparation methods of AO-based polyethylene fibers.

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

    SciTech Connect

    Kenichiro Inoue; Katsuya Kawamoto

    2005-08-01

    Carbonaceous adsorbents such as activated carbon have been used to reduce the emission of organic pollutants from municipal solid wastes incineration plants. However, with this method, the amount and type of adsorbent to be used are based only on empirical results, which may lead to overuse of the adsorbents. The fundamental adsorption characteristics of several kinds of activated carbon, activated coke, and carbide wood were examined using 1,2,3,4-tetrachlorobenzene as an adsorbate. The removal performance and various equilibrium adsorption characteristics of these adsorbents were analyzed using laboratory-scale adsorption equipment. The equilibrium adsorption amount increased by a factor of 1.9-3.2 at 150{sup o}C compared with that at 190{sup o}C. The effect of the moisture content on adsorption capacity was relatively small in comparison with that of the temperature. The micropore volume for pore diameters of 2 nm or less was the most important factor governing the adsorption capacity for all adsorbents. Activated carbon showed superior adsorption ability compared to activated coke and carbide wood, although all adsorbents were sufficient for practical use. 45 refs., 10 figs., 6 tabs.

  11. Atmospheric fate of oil matter adsorbed on sea salt particles under UV light

    NASA Astrophysics Data System (ADS)

    Vaitilingom, M.; Avij, P.; Huang, H.; Valsaraj, K. T.

    2014-12-01

    The presence of liquid petroleum hydrocarbons at the sea water surface is an important source of marine pollution. An oil spill in sea-water will most likely occur due to an involuntary accident from tankers, offshore platforms, etc. However, a large amount of oil is also deliberately spilled in sea-water during the clean-out process of tank vessels (e.g. for the Mediterranean Sea, 490,000 tons/yr). Moreover, the pollution caused by an oil spill does not only affect the aquatic environment but also is of concern for the atmospheric environment. A portion of the oil matter present at the sea-water surface is transported into the atmosphere viaevaporation and adsorption at the surface of sea spray particles. Few studies are related to the presence of oil matter in airborne particles resulting from their adsorption on sea salt aerosols. We observed that the non-volatile oil matter was adsorbed at the surface of sea-salt crystals (av. size of 1.1 μm). Due to their small size, these particles can have a significant residence time in the atmosphere. The hydrocarbon matter adsorbed at the surface of these particles can also be transformed by catalyzers present in the atmosphere (i.e. UV, OH, O3, ...). In this work, we focused on the photo-oxidation rates of the C16 to C30alkanes present in these particles. We utilized a bubble column reactor, which produced an abundance of small sized bubbles. These bubbles generated droplets upon bursting at the air-salt water interface. These droplets were then further dried up and lifted to the top of the column where they were collected as particles. These particles were incubated in a controlled reactor in either dark conditions or under UV-visible light. The difference of alkane content analyzed by GC-MS between the particles exposed to UV or the particles not exposed to UV indicated that up to 20% in mass was lost after 20 min of light exposure. The degradation kinetics varied for each range of alkanes (C16-20, C21-25, C26

  12. Adsorbed Fibrinogen Enhances Production of Bone- and Angiogenic-Related Factors by Monocytes/Macrophages

    PubMed Central

    Maciel, Joana; Oliveira, Marta I.; Colton, Erica; McNally, Amy K.; Oliveira, Carla; Anderson, James M.

    2014-01-01

    Macrophages are phagocytic cells with great importance in guiding multiple stages of inflammation and tissue repair. By producing a large number of biologically active molecules, they can affect the behavior of other cells and events, such as the foreign body response and angiogenesis. Since protein adsorption to biomaterials is crucial for the inflammatory process, we addressed the ability of the pro-inflammatory molecule fibrinogen (Fg) to modulate macrophage behavior toward tissue repair/regeneration. For this purpose, we used chitosan (Ch) as a substrate for Fg adsorption. Freshly isolated human monocytes were seeded on Ch substrates alone or previously adsorbed with Fg, and allowed to differentiate into macrophages for 10 days. Cell adhesion and morphology, formation of foreign body giant cells (FBGC), and secretion of a total of 80 cytokines and growth factors were evaluated. Both substrates showed similar numbers of adherent macrophages along differentiation as compared with RGD-coated surfaces, which were used as positive controls. Fg did not potentiate FBGC formation. In addition, actin cytoskeleton staining revealed the presence of punctuate F-actin with more elongated and interconnecting cells on Ch substrates. Antibody array screening and quantification of inflammation- and wound-healing-related factors indicated an overall reduction in Ch-based substrates versus RGD-coated surfaces. At late times, most inflammatory agents were down-regulated in the presence of Fg, in contrast to growth factor production, which was stimulated by Fg. Importantly, on Ch+Fg substrates, fully differentiated macrophages produced significant amounts of macrophage inflammatory protein-1delta (MIP-1δ), platelet-derived growth factor-BB, bone morphogenetic protein (BMP)-5, and BMP-7 compared with Ch alone. In addition, other important factors involved in bone homeostasis and wound healing, such as growth hormone, transforming growth factor-β3, and insulin-like growth factor

  13. Mimetite Formation from Goethite-Adsorbed Ions.

    PubMed

    Kleszczewska-Zębala, Anna; Manecki, Maciej; Bajda, Tomasz; Rakovan, John; Borkiewicz, Olaf J

    2016-06-01

    Bioavailability of arsenic in contaminated soils and wastes can be reduced to insignificant levels by precipitation of mimetite Pb5(AsO4)3Cl. The objective of this study is to elucidate mechanisms of the reaction between solution containing lead ions and arsenates adsorbed on synthetic goethite (AsO4-goethite), or arsenate ions in the solution and goethite saturated with adsorbed Pb (Pb-goethite). These reactions, in the presence of Cl, result in rapid crystallization of mimetite. Formation of mimetite is faster than desorption of AsO4 but slower than desorption of Pb from the goethite surface. Slow desorption of arsenates from AsO4-goethite results in heterogeneous precipitation and formation of mimetite incrustation on goethite crystals. Desorption of lead from Pb-goethite is at least as fast as diffusion and advection of AsO4 and Cl in suspension allowing for homogeneous crystallization of mimetite in intergranular solution. Therefore, the mechanism of nucleation is primarily driven by the kinetics of constituent supply to the saturation front, rather than by the thermodynamics of nucleation. The products of the reactions are well documented using microscopy methods such as scanning electron microscopy, electron backscattered diffraction, X-ray diffraction, and Fourier transform infrared spectroscopy.

  14. The persistence length of adsorbed dendronized polymers.

    PubMed

    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

  15. Optimizing heterosurface adsorbent synthesis for liquid chromatography

    NASA Astrophysics Data System (ADS)

    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 < 6 nm do not change during HA synthesis, while the volume of pores with diameters of 6 nm < D < 9 nm shrinks slightly due to the adsorption of albumin in the pore orifices. It is established that the volume of 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. Equilibrium molecular theory of two-dimensional adsorbate drops on surfaces of heterogeneous adsorbents

    NASA Astrophysics Data System (ADS)

    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.

  17. 29 CFR 4219.13 - Amount of liability for de minimis amounts.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 29 Labor 9 2011-07-01 2011-07-01 false Amount of liability for de minimis amounts. 4219.13 Section... Redetermination of Withdrawal Liability Upon Mass Withdrawal § 4219.13 Amount of liability for de minimis amounts. An employer that is liable for de minimis amounts shall be liable to the plan for the amount by...

  18. pH Dependence of Adsorbed Fibrinogen Conformation and Its Effect on Platelet Adhesion.

    PubMed

    Hu, Yu; Jin, Jing; Liang, Haojun; Ji, Xiangling; Yin, Jinghua; Jiang, Wei

    2016-04-26

    Quartz crystal microbalance with dissipation (QCM-D) and dual polarization interferometry (DPI) were used to investigate fibrinogen (Fib) adsorption behavior on different surfaces by changing the pH value. Moreover, integrin adhesion to the adsorbed Fibs was studied using DPI. Qualitative and quantitative studies of platelet adhesion to the adsorbed Fibs were performed using scanning electron microscopy (SEM), confocal laser scanning microscope (CLSM), and released lactate dehydrogenase (LDH) assay. Experimental results indicated that the conformation and orientation of the absorbed Fibs depended on surface property and pH cycling. For the hydrophilic surface, Fibs adsorbed at pH 7.4 and presented a αC-hidden orientation. As a result, no integrin adhesion was observed, and a small number of platelets were adhered because the αC-domains were hidden under the Fib molecule. By changing the rinsing solution pH from 7.4 to 3.2 and then back to 7.4, the adsorbed Fib orientation became αC-exposed via the transformation of Fib conformation during pH cycling. Therefore, integrin adhesion was more likely to occur, and more platelets were adhered and activated. For the hydrophobic surface, the adsorbed Fibs became more spread and stretched due to the strong interaction between the Fibs and surface. αC-exposed orientation remained unchanged when the rinsing solution pH changed from 7.4 to 3.2 and then back to 7.4. Therefore, a large number of integrins and platelets were adhered to the adsorbed Fibs, and almost all of the adhered platelets were activated. PMID:27035056

  19. Extraction of uranium from seawater using magnetic adsorbents

    SciTech Connect

    Yamashita, H.; Fujita, K.; Nakajima, F.; Ozawa, Y.; Murata, T.

    1981-01-01

    A new process for the extraction of uranium from seawater was developed. In the process, uranium adsorption is effected using powdered magnetic adsorbents; the adsorbents are then separated from seawater using magnetic separation technology. This process is superior to a column method using a granulated hydrous titanium oxide adsorber bed in the following ways: (1) a higher rate of adsorption is realized because smaller particles are used in the uranium adsorption; and (2) blocking, which is inevitable in an adsorber bed, is eliminated. The composite hydrous titanium-iron oxide as a magnetic adsorbent having high uranium adsorption capacity and magnetization can be prepared by adding urea to a mixed solution of titanium sulfate and ferrous sulfate. Adsorption and desoprtion of uranium and the removal of the adsorbent using a small-scale uranium extraction plant (about 15 m/sup 3//d) is reported, and the feasibility of uranium extraction from seawater by this process is demonstrated. 10 figures.

  20. Functionalized-MnO2/chitosan nanocomposites: A promising adsorbent for the removal of lead ions.

    PubMed

    Mallakpour, Shadpour; Madani, Maryam

    2016-08-20

    In the current study, the surface of alpha manganese dioxide nanorod (α-MnO2) functionalized with γ-aminopropyltriethoxysilane (APTS). The α-MnO2-APTS was used as filler for preparation of chitosan (CS) nanocomposites (NCs). The α-MnO2-APTS/CS NCs were crosslinked with different amount of glutaraldehyde (GA). The effects of the GA content on the morphology, thermal properties and adsorption of NC films were studied. The Fourier transform infrared (FT-IR) results verified the grafting of APTS onto α-MnO2. The amount of APTS grafted onto α-MnO2 was found to be 20wt% by thermo gravimetric analysis. Presented results also show that with increasing crosslinker agent concentration, the thermal stability of CS films were increased. The α-MnO2-APTS/CS NCs were tested and evaluated as a potential adsorbent for the removal of lead ions. The results showed that the adsorbent exhibited a favorable performance for the removal of lead ions. Therefore, α-MnO2-APTS/CS NCs could serve as promising adsorbents. PMID:27178908

  1. Treatment of malachite green-containing wastewater using poultry feathers as adsorbent.

    PubMed

    Beak, Mi H; Ijagbemi, Christianah O; Kim, Dong S

    2009-04-01

    The feasibility of using feathers, a waste from poultry as an absorbent for malachite green in dye wastewater was studied. The batch adsorption tests were shown to be influenced by the concentration of the dye, reaction temperature, solution pH, and pre-treatment with ethanol. In order to establish the equilibrium state of the process, a kinetic study was conducted for an optimal practice of adsorption treatment process. The adsorption reached equilibrium within 120 min in the range of dye concentration studied. It was found that the adsorption rate increases especially at low concentrations of dye and the adsorption data fitted well to the first-order reaction kinetics over all dye concentration range. Absolute amount of adsorbed malachite green at equilibrium condition decreased as concentration decreases. Adsorption of malachite green on poultry feathers fitted well to the Langmuir isotherm model. As temperature increases, the adsorbed amount of malachite green at equilibrium also increased, indicating an endothermic adsorption reaction. In addition, the color removal of malachite green rapidly increased with increase in dye's water pH. The pre-treatment of adsorbent with ethanol produced initial slow rate of malachite green removal but after about 100 min of reaction time, same removal rate was observed compare with the untreated feathers.

  2. Recovery of iron oxides from acid mine drainage and their application as adsorbent or catalyst.

    PubMed

    Flores, Rubia Gomes; Andersen, Silvia Layara Floriani; Maia, Leonardo Kenji Komay; José, Humberto Jorge; Moreira, Regina de Fatima Peralta Muniz

    2012-11-30

    Iron oxide particles recovered from acid mine drainage represent a potential low-cost feedstock to replace reagent-grade chemicals in the production of goethite, ferrihydrite or magnetite with relatively high purity. Also, the properties of iron oxides recovered from acid mine drainage mean that they can be exploited as catalysts and/or adsorbents to remove azo dyes from aqueous solutions. The main aim of this study was to recover iron oxides with relatively high purity from acid mine drainage to act as a catalyst in the oxidation of dye through a Fenton-like mechanism or as an adsorbent to remove dyes from an aqueous solution. Iron oxides (goethite) were recovered from acid mine drainage through a sequential precipitation method. Thermal treatment at temperatures higher than 300 °C produces hematite through a decrease in the BET area and an increase in the point of zero charge. In the absence of hydrogen peroxide, the solids adsorbed the textile dye Procion Red H-E7B according to the Langmuir model, and the maximum amount adsorbed decreased as the temperature of the thermal treatment increased. The decomposition kinetics of hydrogen peroxide is dependent on the H(2)O(2) concentration and iron oxides dosage, but the second-order rate constant normalized to the BET surface area is similar to that for different iron oxides tested in this and others studies. These results indicate that acid mine drainage could be used as a source material for the production of iron oxide catalysts/adsorbents, with comparable quality to those produced using analytical-grade reagents.

  3. Bubble-surface interactions with graphite in the presence of adsorbed carboxymethylcellulose.

    PubMed

    Wu, Jueying; Delcheva, Iliana; Ngothai, Yung; Krasowska, Marta; Beattie, David A

    2015-01-21

    The adsorption of carboxymethylcellulose (CMC), and the subsequent effect on bubble-surface interactions, has been studied for a graphite surface. CMC adsorbs on highly oriented pyrolytic graphite (HOPG) in specific patterns: when adsorbed from a solution of low concentration it forms stretched, isolated and sparsely distributed chains, while upon adsorption from a solution of higher concentration, it forms an interconnected network of multilayer features. The amount and topography of the adsorbed CMC affect the electrical properties as well as the wettability of the polymer-modified HOPG surface. Adsorption of CMC onto the HOPG surface causes the zeta potential to be more negative and the modified surface becomes more hydrophilic. This increase in both the absolute value of zeta potential and the surface hydrophilicity originates from the carboxymethyl groups of the CMC polymer. The effect of the adsorbed polymer layer on wetting film drainage and bubble-surface/particle attachment was determined using high speed video microscopy to monitor single bubble-surface collision, and single bubble Hallimond tube flotation experiments. The time of wetting film drainage and the time of three-phase contact line spreading gets significantly longer for polymer-modified HOPG surfaces, indicating that the film rupture and three-phase contact line expansion were inhibited by the presence of polymer. The effect of longer drainage times and slower dewetting correlated with reduced flotation recovery. The molecular kinetic (MK) model was used to quantify the effect of the polymer on dewetting dynamics, and showed an increase in the jump frequency for the polymer adsorbed at the higher concentration.

  4. Isomerization reactions on single adsorbed molecules.

    PubMed

    Morgenstern, Karina

    2009-02-17

    Molecular switches occur throughout nature. In one prominent example, light induces the isomerization of retinal from the compact 11-cis form to the elongated all-trans form, a conversion that triggers the transformation of light into a neural impulse in the eye. Applying these natural principles to synthetic systems offers a promising way to construct smaller and faster nanoelectronic devices. In such systems, electronic switches are essential components for storage and logical operations. The development of molecular switches on the single-molecule level would represent a major step toward incorporating molecules as building units into nanoelectronic circuits. Molecular switches must be both reversible and bistable. To meet these requirements, a molecule must have at least two different thermally stable forms and a way to repeatedly interconvert between those forms based on changes in light, heat, pressure, magnetic or electric fields, pH, mechanical forces, or electric currents. The conversion should be connected to a measurable change in electronic, optical, magnetic, or mechanical properties. Because isomers can differ significantly in physical and chemical properties, isomerization could serve as a molecular switching mechanism. Integration of molecular switches into larger circuits will probably require arranging them on surfaces, which will require a better understanding of isomerization reactions in these environments. In this Account, we describe our scanning tunneling microscopy studies of the isomerization of individual molecules adsorbed on metal surfaces. Investigating chlorobenzene and azobenzene derivatives on the fcc(111) faces of Ag, Cu, and Au, we explored the influence of substituents and the substrate on the excitation mechanism of the isomerization reaction induced by inelastically tunneling electrons. We achieved an irreversible configurational (cis-trans) isomerization of individual 4-dimethyl-amino-azobenzene-4-sulfonic acid molecules on Au

  5. Carbonaceous adsorbent regeneration and halocarbon displacement by hydrocarbon gases

    DOEpatents

    Senum, Gunnar I.; Dietz, Russell N.

    1994-01-01

    This invention describes a process for regeneration of halocarbon bearing carbonaceous adsorbents through which a carbonaceous adsorbent is contacted with hydrocarbon gases, preferably propane, butane and pentane at near room temperatures and at atmospheric pressure. As the hydrocarbon gases come in contact with the adsorbent, the hydrocarbons displace the halocarbons by physical adsorption. As a result of using this process, the halocarbon concentration and the hydrocarbon eluant is increased thereby allowing for an easier recovery of pure halocarbons. By using the process of this invention, carbonaceous adsorbents can be regenerated by an inexpensive process which also allows for subsequent re-use of the recovered halocarbons.

  6. Carbonaceous adsorbent regeneration and halocarbon displacement by hydrocarbon gases

    DOEpatents

    Senum, G.I.; Dietz, R.N.

    1994-04-05

    This invention describes a process for regeneration of halocarbon bearing carbonaceous adsorbents through which a carbonaceous adsorbent is contacted with hydrocarbon gases, preferably propane, butane and pentane at near room temperatures and at atmospheric pressure. As the hydrocarbon gases come in contact with the adsorbent, the hydrocarbons displace the halocarbons by physical adsorption. As a result of using this process, the halocarbon concentration and the hydrocarbon eluant is increased thereby allowing for an easier recovery of pure halocarbons. By using the process of this invention, carbonaceous adsorbents can be regenerated by an inexpensive process which also allows for subsequent re-use of the recovered halocarbons. 8 figures.

  7. Calibrating the Bending of Molecule Adsorbed Nanoscale Si Cantilevers with a Modified Stoney Formula

    NASA Astrophysics Data System (ADS)

    Zang, Ji; Liu, Feng

    2007-03-01

    Fundamental understanding of mechanical bending of molecule adsorbed nanoscale thin films is of both scientific and technological importance. Our current understanding, however, is limited within macroscopic analysis that neglects the atomic details of film structure and surface effects. Here, we report atomistic simulation and theoretical analysis of bending of freestanding nanometer-thick silicon (Si) films induced by adsorption of hydrogen and acetylene molecules. It reveals the dominant role of atomic surface structure and surface stress in governing their bending behavior. We show that the bending curvature of molecule adsorbed Si nanofilm does not follow the classical Stoney formula, and we develop a modified Stoney formula by taking into account of the effects arising from atomic surface reconstruction and surface stress. Our findings suggest that re-calibration has to be made in detecting trace amount of molecules by nanoscale Si mechanochemical sensors.

  8. 24 CFR 201.10 - Loan amounts.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 24 Housing and Urban Development 2 2010-04-01 2010-04-01 false Loan amounts. 201.10 Section 201.10... IMPROVEMENT AND MANUFACTURED HOME LOANS Loan and Note Provisions § 201.10 Loan amounts. (a) Property... following maximum loan amounts: (i) Single family property improvement loans—$25,000, except that a loan...

  9. 29 CFR 4302.3 - Penalty amount.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 29 Labor 9 2010-07-01 2010-07-01 false Penalty amount. 4302.3 Section 4302.3 Labor Regulations... PENALTIES FOR FAILURE TO PROVIDE CERTAIN MULTIEMPLOYER PLAN NOTICES § 4302.3 Penalty amount. The maximum daily amount of the penalty under section 4302 of ERISA shall be $110....

  10. 33 CFR 25.513 - Amount claimed.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 33 Navigation and Navigable Waters 1 2010-07-01 2010-07-01 false Amount claimed. 25.513 Section 25.513 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY GENERAL CLAIMS Foreign Claims § 25.513 Amount claimed. The claimant shall state the amount claimed in the currency of...

  11. 31 CFR 50.95 - Final amount.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 31 Money and Finance: Treasury 1 2010-07-01 2010-07-01 false Final amount. 50.95 Section 50.95... on Annual Liability § 50.95 Final amount. (a) Treasury shall determine if, as a final proration... that in the aggregate bring the insurer's total insured loss payments up to an amount equal to...

  12. 14 CFR 1261.102 - Maximum amount.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 14 Aeronautics and Space 5 2011-01-01 2010-01-01 true Maximum amount. 1261.102 Section 1261.102...) Employees' Personal Property Claims § 1261.102 Maximum amount. From October 1, 1982, to October 30, 1988, the maximum amount that may be paid under the Military Personnel and Civilian Employees' Claim Act...

  13. 29 CFR 4071.3 - Penalty amount.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 29 Labor 9 2011-07-01 2011-07-01 false Penalty amount. 4071.3 Section 4071.3 Labor Regulations... FAILURE TO PROVIDE CERTAIN NOTICES OR OTHER MATERIAL INFORMATION § 4071.3 Penalty amount. The maximum daily amount of the penalty under section 4071 of ERISA shall be $1,100....

  14. 33 CFR 135.203 - Amount required.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 33 Navigation and Navigable Waters 2 2010-07-01 2010-07-01 false Amount required. 135.203 Section... Financial Responsibility for Offshore Facilities § 135.203 Amount required. (a) Each facility that is used... the amount of $35,000,000. (b) Evidence of financial responsibility established and maintained by...

  15. 13 CFR 500.202 - Loan amount.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 13 Business Credit and Assistance 1 2010-01-01 2010-01-01 false Loan amount. 500.202 Section 500.202 Business Credit and Assistance EMERGENCY OIL AND GAS GUARANTEED LOAN BOARD EMERGENCY OIL AND GAS GUARANTEED LOAN PROGRAM Oil and Gas Guaranteed Loans § 500.202 Loan amount. The aggregate amount of...

  16. 46 CFR 308.100 - Insured amount.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 46 Shipping 8 2010-10-01 2010-10-01 false Insured amount. 308.100 Section 308.100 Shipping... and Disbursements Insurance § 308.100 Insured amount. An applicant for war risk hull insurance shall state the amount of insurance desired but any payment of claim for damage to or actual or...

  17. 33 CFR 135.203 - Amount required.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 33 Navigation and Navigable Waters 2 2011-07-01 2011-07-01 false Amount required. 135.203 Section... Financial Responsibility for Offshore Facilities § 135.203 Amount required. (a) Each facility that is used... the amount of $35,000,000. (b) Evidence of financial responsibility established and maintained by...

  18. 5 CFR 838.1006 - Amounts payable.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 5 Administrative Personnel 2 2011-01-01 2011-01-01 false Amounts payable. 838.1006 Section 838... Benefits § 838.1006 Amounts payable. (a) Money held by an executive agency or OPM that may be payable at... payments (refunds), the amount of the lump-sum credit. (3) In cases involving former spouse annuities,...

  19. 29 CFR 4302.3 - Penalty amount.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 29 Labor 9 2011-07-01 2011-07-01 false Penalty amount. 4302.3 Section 4302.3 Labor Regulations... PENALTIES FOR FAILURE TO PROVIDE CERTAIN MULTIEMPLOYER PLAN NOTICES § 4302.3 Penalty amount. The maximum daily amount of the penalty under section 4302 of ERISA shall be $110....

  20. 29 CFR 4071.3 - Penalty amount.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 29 Labor 9 2010-07-01 2010-07-01 false Penalty amount. 4071.3 Section 4071.3 Labor Regulations... FAILURE TO PROVIDE CERTAIN NOTICES OR OTHER MATERIAL INFORMATION § 4071.3 Penalty amount. The maximum daily amount of the penalty under section 4071 of ERISA shall be $1,100....

  1. 46 CFR 308.100 - Insured amount.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 46 Shipping 8 2011-10-01 2011-10-01 false Insured amount. 308.100 Section 308.100 Shipping... and Disbursements Insurance § 308.100 Insured amount. An applicant for war risk hull insurance shall state the amount of insurance desired but any payment of claim for damage to or actual or...

  2. 14 CFR 1261.102 - Maximum amount.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 14 Aeronautics and Space 5 2010-01-01 2010-01-01 false Maximum amount. 1261.102 Section 1261.102...) Employees' Personal Property Claims § 1261.102 Maximum amount. From October 1, 1982, to October 30, 1988, the maximum amount that may be paid under the Military Personnel and Civilian Employees' Claim Act...

  3. 46 CFR 308.403 - Insured amounts.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 46 Shipping 8 2011-10-01 2011-10-01 false Insured amounts. 308.403 Section 308.403 Shipping... Builder's Risk Insurance § 308.403 Insured amounts. (a) Prelaunching period. The amount insured during... 10 percent, all as determined from the builder's records. (b) Postlaunching period. The...

  4. 31 CFR 50.95 - Final amount.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 31 Money and Finance: Treasury 1 2011-07-01 2011-07-01 false Final amount. 50.95 Section 50.95... on Annual Liability § 50.95 Final amount. (a) Treasury shall determine if, as a final proration... that in the aggregate bring the insurer's total insured loss payments up to an amount equal to...

  5. 33 CFR 25.513 - Amount claimed.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 33 Navigation and Navigable Waters 1 2011-07-01 2011-07-01 false Amount claimed. 25.513 Section 25.513 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY GENERAL CLAIMS Foreign Claims § 25.513 Amount claimed. The claimant shall state the amount claimed in the currency of...

  6. 31 CFR 235.5 - Reclamation amounts.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 31 Money and Finance:Treasury 2 2011-07-01 2011-07-01 false Reclamation amounts. 235.5 Section 235.5 Money and Finance: Treasury Regulations Relating to Money and Finance (Continued) FISCAL SERVICE... ON DESIGNATED DEPOSITARIES § 235.5 Reclamation amounts. Amounts received by way of reclamation...

  7. 46 CFR 308.403 - Insured amounts.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 46 Shipping 8 2010-10-01 2010-10-01 false Insured amounts. 308.403 Section 308.403 Shipping... Builder's Risk Insurance § 308.403 Insured amounts. (a) Prelaunching period. The amount insured during... 10 percent, all as determined from the builder's records. (b) Postlaunching period. The...

  8. 12 CFR 1208.75 - Amounts withheld.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 12 Banks and Banking 7 2011-01-01 2011-01-01 false Amounts withheld. 1208.75 Section 1208.75 Banks... Wage Garnishment § 1208.75 Amounts withheld. (a) Upon receipt of the garnishment order issued under... period the amount of garnishment described in paragraphs (b) through (d) of this section. (b) Subject...

  9. 13 CFR 500.202 - Loan amount.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 13 Business Credit and Assistance 1 2011-01-01 2011-01-01 false Loan amount. 500.202 Section 500.202 Business Credit and Assistance EMERGENCY OIL AND GAS GUARANTEED LOAN BOARD EMERGENCY OIL AND GAS GUARANTEED LOAN PROGRAM Oil and Gas Guaranteed Loans § 500.202 Loan amount. The aggregate amount of...

  10. 7 CFR 1424.8 - Payment amounts.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 7 Agriculture 10 2012-01-01 2012-01-01 false Payment amounts. 1424.8 Section 1424.8 Agriculture... AGRICULTURE LOANS, PURCHASES, AND OTHER OPERATIONS BIOENERGY PROGRAM § 1424.8 Payment amounts. (a) An eligible producer may be paid the amount specified in this section, subject to the availability of funds....

  11. 7 CFR 1424.8 - Payment amounts.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 7 Agriculture 10 2011-01-01 2011-01-01 false Payment amounts. 1424.8 Section 1424.8 Agriculture... AGRICULTURE LOANS, PURCHASES, AND OTHER OPERATIONS BIOENERGY PROGRAM § 1424.8 Payment amounts. (a) An eligible producer may be paid the amount specified in this section, subject to the availability of funds....

  12. 7 CFR 1424.8 - Payment amounts.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 7 Agriculture 10 2014-01-01 2014-01-01 false Payment amounts. 1424.8 Section 1424.8 Agriculture... AGRICULTURE LOANS, PURCHASES, AND OTHER OPERATIONS BIOENERGY PROGRAM § 1424.8 Payment amounts. (a) An eligible producer may be paid the amount specified in this section, subject to the availability of funds....

  13. 24 CFR 594.15 - Allocation amounts.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 24 Housing and Urban Development 3 2010-04-01 2010-04-01 false Allocation amounts. 594.15 Section... DEVELOPMENT COMMUNITY FACILITIES JOHN HEINZ NEIGHBORHOOD DEVELOPMENT PROGRAM Funding Allocation and Criteria § 594.15 Allocation amounts. (a) Amounts and match requirement. HUD will make grants, in the form...

  14. 31 CFR 235.5 - Reclamation amounts.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 31 Money and Finance: Treasury 2 2010-07-01 2010-07-01 false Reclamation amounts. 235.5 Section 235.5 Money and Finance: Treasury Regulations Relating to Money and Finance (Continued) FISCAL SERVICE... ON DESIGNATED DEPOSITARIES § 235.5 Reclamation amounts. Amounts received by way of reclamation...

  15. Air stripper VOC treatment using specialized adsorbents

    SciTech Connect

    Craven, C.N.; Blystone, P.G.; Grant, A.

    1994-12-31

    Abatement of volatile organic compound (VOC) emissions is required by federal, state and local regulatory agencies. Sources of VOC emissions include air stripping processes at groundwater remediation and industrial wastewater operations. The Purus A2000 system is an innovative emission control system that utilizes specialized adsorbent resins, on-site regeneration and solvent recovery for abatement of VOCs. This paper describes two applications in which air stripper off-gas is treated by the Purus A2000 Adsorption System. The first is a groundwater remediation pump-and-treat operation in which the air stripper off-gas contains chlorinated solvents. At the second site, benzene and styrene emissions from an industrial wastewater air stripper operation were successfully treated. At both sites the recovered solvent was recycled. Capital and operating costs will be compared to other treatment methods.

  16. Trends in adsorbate induced core level shifts

    NASA Astrophysics Data System (ADS)

    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.

  17. Linear transport models for adsorbing solutes

    NASA Astrophysics Data System (ADS)

    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.

  18. The persistence length of adsorbed dendronized polymers

    NASA Astrophysics Data System (ADS)

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

    2016-07-01

    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.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

  19. Efficiency of sepiolite in broilers diet as uranium adsorbent.

    PubMed

    Mitrović, Branislava M; Jovanović, Milijan; Lazarević-Macanović, Mirjana; Janaćković, Djordje; Krstić, Nikola; Stojanović, Mirjana; Mirilović, Milorad

    2015-05-01

    The use of phosphate mineral products in animal nutrition, as a major source of phosphor and calcium, can lead to uranium entering the food chain. The aim of the present study was to determine the protective effect of natural sepiolite and sepiolite treated with acid for broilers after oral intake of uranium. The broilers were contaminated for 7 days with 25 mg/uranyl nitrate per day. Two different adsorbents (natural sepiolite and sepiolite treated with acid) were given via gastric tube immediately after the oral administration of uranium. Natural sepiolite reduced uranium distribution by 57% in kidney, 80% in liver, 42% in brain, and 56% in muscle. A lower protective effect was observed after the administration of sepiolite treated with acid, resulting in significant damage of intestinal villi in the form of shortening, fragmentation, and necrosis, and histopathological lesions on kidney in the form of edema and abruption of epithelial cells in tubules. When broilers received only sepiolite treated with acid (no uranyl nitrate), shortening of intestinal villi occurred. Kidney injuries were evident when uranium concentrations in kidney were 0.88 and 1.25 µg/g dry weight. It is concluded that adding of natural sepiolite to the diets of broilers can reduce uranium distribution in organs by significant amount without adverse side effects.

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

    PubMed

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

    2016-09-23

    In this work, phenyl-functionalized magnetic graphene/mesoporous silica composites (MG-mSiO2-Ph) were prepared and applied as restricted access matrix solid phase extraction (RAM-SPE) adsorbents to determine the parabens in commercially available retail cosmetics. MG-mSiO2-Ph composites were synthesized by a surfactant-mediated co-condensation reaction in which mesoporous silica with phenyl-functionalized pore-walls was coated on a magnetic graphene sheet. The obtained nano-composites were proven to be of sufficient quality for an ideal RAM-SPE adsorbent with a large specific surface area of 369m(2)g(-1), uniform mesopores of 2.8nm, and special phenyl-functionalized pore-walls. Parabens, such as methyl paraben, ethyl paraben and propyl paraben, were extracted from water-based skin toners using one step of the RAM-SPE and were then analysed by a HPLC-DAD system. The SPE conditions were optimized by studying the parameters, such as the adsorbent amount, elution solvent type, adsorption time and desorption time, that influence the extraction efficiency. For each analyte, there were good linearities of approximately 0.10-120μgmL(-1) with determination coefficients (R(2))>0.995. The sensitivity was as low as 0.01-0.025μgmL(-1) for the LOD, and the percent recoveries were 98.37-105.84%. The intra-day and inter-day RSDs were 1.44-6.11% (n=6) and 3.12-11.70% (n=6), respectively. The results indicated that this method with novel RAM-SPE adsorbents is sensitive and convenient. The results also offered an attractive alternative for the extraction and determination of paraben preservatives in a complex matrix, such as cosmetics. PMID:27575922

  1. Formation Process of Eosin Y-Adsorbing ZnO Particles by Electroless Deposition and Their Photoelectric Conversion Properties.

    PubMed

    Nagaya, Satoshi; Nishikiori, Hiromasa; Mizusaki, Hideaki; Wagata, Hajime; Teshima, Katsuya

    2015-06-01

    The thin films consisting of crystalline ZnO particles were prepared on fluorine-doped tin oxide electrodes by electroless deposition. The particles were deposited from an aqueous solution containing zinc nitrate, dimethyamine-borane, and eosin Y at 328 K. As the Pd particles were adsorbed on the substrate, not only the eosin Y monomer but also the dimer and debrominated species were rapidly adsorbed on the spherical ZnO particles, which were aggregated and formed secondary particles. On the other hand, in the absence of the Pd particles, the monomer was adsorbed on the flake-shaped ZnO particles, which vertically grew on the substrate surface and had a high crystallinity. The photoelectric conversion efficiency was higher for the ZnO electrodes containing a higher amount of the monomer during light irradiation. PMID:25978089

  2. Surfactant-modified montmorillonite as a nanosized adsorbent for removal of an insecticide: kinetic and isotherm studies.

    PubMed

    Hassani, Aydin; Khataee, Alireza; Karaca, Semra; Shirzad-Siboni, Mehdi

    2015-01-01

    Surfactant-modified montmorillonites (MMT) were prepared using trimethyloctylammonium bromide (TMOAB) and employed as a nanosized adsorbent to remove diazinon from aqueous solutions. The prepared adsorbent was characterized using Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), scanning electron microscopy (SEM) and energy-dispersive X-ray (EDX). The dependence of removal efficiency on initial diazinon concentration, amount of adsorbent, pH of the solution and ionic strength was investigated. The affinity sequence for ion adsorption on TMOAB/MMT was in the order: without anion> sodium carbonate> sodium bicarbonate> sodium sulphate> sodium chloride. The adsorption kinetic and isotherm were best fit by a pseudo-second-order kinetic and Langmuir isotherm models, respectively. PMID:26006742

  3. Molecular Structure and Equilibrium Forces of Bovine Submaxillary Mucin Adsorbed at a Solid-Liquid Interface.

    PubMed

    Zappone, Bruno; Patil, Navinkumar J; Madsen, Jan B; Pakkanen, Kirsi I; Lee, Seunghwan

    2015-04-21

    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 prepared by additional chromatographic purification of commercially available products. The mucin molecule was found to have a z-average hydrodynamic diameter of ca. 35 nm in phosphate buffered solution, without any particular secondary or tertiary structure. The contour length of the mucin is larger than, 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-ranged, repulsive, and nonhysteretic forces upon compression of the adsorbed layers. Detailed analysis of such forces suggests that adsorbed mucins had an elongated conformation favored by the stiffness of the central domain. Acidification of aqueous media was chosen as means to reduce mucin-mucin and mucin-substrate electrostatic interactions. The hydrodynamic diameter in solution did not significantly change when the pH was lowered, showing that the large persistence length of the mucin molecule is due to steric hindrance between sugar chains, rather than electrostatic interactions. Remarkably, the force generated by an adsorbed layer with a fixed surface coverage also remained unaltered upon acidification. This observation can be linked to the surface-protective, pH-resistant role of bovine submaxillary mucin in the variable environmental conditions of the oral cavity. PMID:25806669

  4. Determination of surface properties of iron hydroxide-coated alumina adsorbent prepared for removal of arsenic from drinking water.

    PubMed

    Hlavay, József; Polyák, Klára

    2005-04-01

    A novel type adsorbent was prepared by in situ precipitation of Fe(OH)3 on the surface of activated Al2O3 as a support material. The iron content of the adsorbent was 0.31+/-0.003% m/m (56.1 mmol/g); its mechanical and chemical stability proved to be appropriate in solutions. The total capacity of the adsorbent was 0.12 mmol/g, and the pH of zero point of charge, pH(zpc) = 6.9+/-0.3. Depending on the pH of solutions, the adsorbent can be used for binding of both anions and cations, if pH(eq) < pH(zpc) anions are sorbed on the surface of adsorbent (S) through [SOH2+] and [SOH] groups. A graphical method was used for the determination of pH(iep) (isoelectric points) of the adsorbent and values of pH(iep) = 6.1+/-0.3 for As(III) and pH(iep) = 8.0+/-0.3 for As(V) ions were found. The amount of surface charged groups (Q) was about zero within the a pH range of 6.5-8.6, due to the practically neutral surface formed on the adsorption of As(V) ions. At acidic pH (pH 4.7), Q = 0.19 mol/kg was obtained. The adsorption of arsenate and arsenite ions from solutions of 0.1-0.4 mmol/L was represented by Langmuir-type isotherms. A great advantage of the adsorbent is that it can be used in adsorption columns, and low waste technology for removal of arsenic from drinking water can be developed.

  5. Lysozyme fractionation from egg white at pilot scale by means of tangential flow membrane adsorbers: Investigation of the flow conditions.

    PubMed

    Brand, Janina; Voigt, Katharina; Zochowski, Bianca; Kulozik, Ulrich

    2016-03-18

    The application of membrane adsorbers instead of classical packed bed columns for protein fractionation is still a growing field. In the case of egg white protein fractionation, the application of classical chromatography is additionally limited due to its high viscosity that impairs filtration. By using tangential flow membrane adsorbers as stationary phase this limiting factor can be left out, as they can be loaded with particle containing substrates. The flow conditions existing in tangential flow membrane adsorbers are not fully understood yet. Thus, the aim of the present study was to gain a deeper understanding of the transport mechanisms in tangential flow membrane adsorbers. It was found that loading in recirculation mode instead of single pass mode increased the binding capacity (0.39 vs. 0.52 mg cm(-2)). Further, it was shown that either higher flow rates (0.39 mg cm(-2) vs. 0.57 mg cm(-2) at 1 CV min(-1) or 20 CV min(-1), respectively) or higher amounts of the target protein in the feed (0.24 mg cm(-2) vs. 0.85 mg cm(-2) for 2.5 or 39.0 g lysozyme, respectively) led to more protein binding. These results show that, in contrast to radial flow or flat sheet membrane adsorbers, the transport in tangential flow membrane adsorbers is not purely based on convection, but on a mix of convection and diffusion. Additionally, investigations concerning the influence of fouling formation were performed that can lead to transport limitations. It was found that this impact is neglectable. It can be concluded that the usage of tangential flow membrane adsorbers is very recommendable for egg white protein fractionations, although the transport is partly diffusion-limited. PMID:26898148

  6. Removal of antibiotics from water using sewage sludge- and waste oil sludge-derived adsorbents.

    PubMed

    Ding, Rui; Zhang, Pengfei; Seredych, Mykola; Bandosz, Teresa J

    2012-09-01

    Sewage sludge- and waste oil sludge-derived materials were tested as adsorbents of pharmaceuticals from diluted water solutions. Simultaneous retention of eleven antibiotics plus two anticonvulsants was examined via batch adsorption experiments. Virgin and exhausted adsorbents were examined via thermal and FTIR analyses to elucidate adsorption mechanisms. Maximum adsorption capacities for the 6 materials tested ranged from 80 to 300 mg/g, comparable to the adsorption capacities of antibiotics on various activated carbons (200-400 mg/g) reported in the literature. The performance was linked to surface reactivity, polarity and porosity. A large volume of pores similar in size to the adsorbate molecules with hydrophobic carbon-based origin of pore walls was indicated as an important factor promoting the separation process. Moreover, the polar surface of an inorganic phase in the adsorbents attracted the functional groups of target molecules. The presence of reactive alkali metals promoted reaction with acidic groups, formation of salts and their precipitation in the pore system. PMID:22673337

  7. Removal of antibiotics from water using sewage sludge- and waste oil sludge-derived adsorbents.

    PubMed

    Ding, Rui; Zhang, Pengfei; Seredych, Mykola; Bandosz, Teresa J

    2012-09-01

    Sewage sludge- and waste oil sludge-derived materials were tested as adsorbents of pharmaceuticals from diluted water solutions. Simultaneous retention of eleven antibiotics plus two anticonvulsants was examined via batch adsorption experiments. Virgin and exhausted adsorbents were examined via thermal and FTIR analyses to elucidate adsorption mechanisms. Maximum adsorption capacities for the 6 materials tested ranged from 80 to 300 mg/g, comparable to the adsorption capacities of antibiotics on various activated carbons (200-400 mg/g) reported in the literature. The performance was linked to surface reactivity, polarity and porosity. A large volume of pores similar in size to the adsorbate molecules with hydrophobic carbon-based origin of pore walls was indicated as an important factor promoting the separation process. Moreover, the polar surface of an inorganic phase in the adsorbents attracted the functional groups of target molecules. The presence of reactive alkali metals promoted reaction with acidic groups, formation of salts and their precipitation in the pore system.

  8. Structural and sorption characteristics of adsorbed humic acid on clay minerals.

    PubMed

    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

  9. The preparation of novel adsorbent materials with efficient adsorption performance for both chromium and methylene blue.

    PubMed

    Li, Leilei; Liu, Feng; Duan, Huimin; Wang, Xiaojiao; Li, Jianbo; Wang, Yanhui; Luo, Chuannan

    2016-05-01

    The hydroxy-functionalized ionic liquids (ILs) modified with magnetic chitosan/grapheneoxide (MG-ILs-OH) were synthesized. The surface morphology of MG-ILs-OH was characterized by transmission electron microscopy, X-ray diffraction, thermo gravimetric analysis and Fourier transform infrared spectroscopy techniques. It was found that the adsorption kinetics is well fitted by a pseudo-second-order model and the adsorption isotherms agree well with the Langmuir model, and the MG-ILs-OH could be repeatedly used by simple treatment. The results showed that the addition of ILs-OH can largely increase the adsorption sites (hydroxy and amino groups) and adsorption properties. The MG-ILs-OH were used as adsorbent for the removal of methylene blue (MB) and Cr(VI) from simulated wastewater with a fast solid-liquid separation in the presence of external magnetic field. The maximum obtained adsorption capacities of MB and Cr(VI) were 243.31 and 107.99 mg/g, respectively. The application of MG-ILs-OH could effectively solve the problem that the adsorbent only adsorb similar adsorbate.

  10. Miscibility of sodium chloride and sodium dodecyl sulfate in the adsorbed film and aggregate.

    PubMed

    Iyota, Hidemi; Krastev, Rumen

    2009-04-01

    The adsorption, micelle formation, and salting out of sodium dodecyl sulfate in the presence of sodium chloride were studied from the viewpoint of their mixed adsorption and aggregate formation. The surface tension of aqueous solutions of a sodium chloride-sodium dodecyl sulfate mixture was measured as a function of the total molality and composition of the mixture. Phase diagrams of adsorption and aggregate formation were obtained by applying thermodynamic equations to the surface tension. Judging from the phase diagrams, sodium chloride and sodium dodecyl sulfate are miscible in the adsorbed film at very large composition of sodium chloride and in the salted-out crystalline particle, while they are immiscible in the micelle. The miscibilities in the adsorbed film, micelle, and crystalline particle increase in the following order: particle > adsorbed film > micelle. The difference in miscibility among the oriented states was ascribed to the difference in geometry between the adsorbed film and micelle and to the interaction between bilayer surfaces in the particle.

  11. Facile preparation of highly hydrophilic, recyclable high-performance polyimide adsorbents for the removal of heavy metal ions.

    PubMed

    Huang, Jieyang; Zheng, Yaxin; Luo, Longbo; Feng, Yan; Zhang, Chaoliang; Wang, Xu; Liu, Xiangyang

    2016-04-01

    To obtain high-performance adsorbents that combine excellent adsorption ability, thermal stability, service life and recycling ability, polyimide (PI)/silica powders were prepared via a facile one-pot coprecipitation process. A benzimidazole unit was introduced into the PI backbone as the adsorption site. The benzimidazole unit induced more hydroxyls onto the silica, which provided hydrophilic sites for access by heavy metal ions. By comprehensively analyzing the effect of hydrophilcity, agglomeration, silica polycondensation, specific surface area and PI crystallinity, 10% was demonstrated to be the most proper feed silica content. The equilibrium adsorption amount (Qe) for Cu(2+) of PI/silica adsorbents was 77 times higher than that of pure PI. Hydrogen chloride (HCl) was used as a desorbent for heavy metal ions and could be decomplexed with benzimidazole unit at around 300°C, which was lower than the glass transition temperature of PI. The complexation and decomplexation process of HCl made PI/silica adsorbents recyclable, and the adsorption ability remained steady for more than 50 recycling processes. As PI/silica adsorbents possess excellent thermal stability, chemical resistance and radiation resistance and hydrophilicity, they have potential as superior recyclable adsorbents for collecting heavy metal ions from waste water in extreme environments. PMID:26736172

  12. Enhanced CO2 adsorptive performance of PEI/SBA-15 adsorbent using phosphate ester based surfactants as additives.

    PubMed

    Cheng, Dandan; Liu, Yue; Wang, Haiqiang; Weng, Xiaole; Wu, Zhongbiao

    2015-12-01

    In this study, a series of polyetherimide/SBA-15: 2-D hexagonal P6mm, Santa Barbara USA (PEI/SBA-15) adsorbents modified by phosphoric ester based surfactants (including tri(2-ethylhexyl) phosphate (TEP), bis(2-ethylhexyl) phosphate (BEP) and trimethyl phosphonoacetate (TMPA)) were prepared for CO2 adsorption. Experimental results indicated that the addition of TEP and BEP had positive effects on CO2 adsorption capacity over PEI/SBA-15. In particular, the CO2 adsorption amount could be improved by around 20% for 45PEI-5TEP/SBA-15 compared to the additive-free adsorbent. This could be attributed to the decrease of CO2 diffusion resistance in the PEI bulk network due to the interactions between TEP and loaded PEI molecules, which was further confirmed by adsorption kinetics results. In addition, it was also found that the cyclic performance of the TEP-modified adsorbent was better than the surfactant-free one. This could be due to two main reasons, based on the results of in situ DRIFT and TG-DSC tests. First and more importantly, adsorbed CO2 species could be desorbed more rapidly over TEP-modified adsorbent during the thermal desorption process. Furthermore, the enhanced thermal stability after TEP addition ensured lower degradation of amine groups during adsorption/desorption cycles. PMID:26702962

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

    PubMed

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

    2014-04-30

    A new activated carbon (AC) material was prepared by pyrolysis of a mixture of coffee grounds, eucalyptus sawdust, calcium hydroxide and soybean oil at 800°C. This material was used as adsorbent for the removal of the endocrine disruptor compounds 17β-estradiol (E2) and 17α-ethinylestradiol (EE2) from aqueous solutions. The carbon material was characterized by scanning electron microscopy (SEM), infrared spectroscopy (FTIR), N2 adsorption/desorption curves and point of zero charge (pHPZC). Variables including the initial pH of the adsorbate solutions, adsorbent masses and contact time were optimized. The optimum range of initial pH for removal of endocrine disruptor compounds (EDC) was 2.0-11.0. The kinetics of adsorption were investigated using general order, pseudo first-order and pseudo-second order kinetic models. The Sips isotherm model gave the best fits of the equilibrium data (298K). The maximum amounts of E2 and EE2 removed at 298K were 7.584 (E2) and 7.883mgg(-1) (EE2) using the AC as adsorbent. The carbon adsorbent was employed in SPE (solid phase extraction) of E2 and EE2 from aqueous solutions. PMID:24647264

  14. Enhanced CO2 adsorptive performance of PEI/SBA-15 adsorbent using phosphate ester based surfactants as additives.

    PubMed

    Cheng, Dandan; Liu, Yue; Wang, Haiqiang; Weng, Xiaole; Wu, Zhongbiao

    2015-12-01

    In this study, a series of polyetherimide/SBA-15: 2-D hexagonal P6mm, Santa Barbara USA (PEI/SBA-15) adsorbents modified by phosphoric ester based surfactants (including tri(2-ethylhexyl) phosphate (TEP), bis(2-ethylhexyl) phosphate (BEP) and trimethyl phosphonoacetate (TMPA)) were prepared for CO2 adsorption. Experimental results indicated that the addition of TEP and BEP had positive effects on CO2 adsorption capacity over PEI/SBA-15. In particular, the CO2 adsorption amount could be improved by around 20% for 45PEI-5TEP/SBA-15 compared to the additive-free adsorbent. This could be attributed to the decrease of CO2 diffusion resistance in the PEI bulk network due to the interactions between TEP and loaded PEI molecules, which was further confirmed by adsorption kinetics results. In addition, it was also found that the cyclic performance of the TEP-modified adsorbent was better than the surfactant-free one. This could be due to two main reasons, based on the results of in situ DRIFT and TG-DSC tests. First and more importantly, adsorbed CO2 species could be desorbed more rapidly over TEP-modified adsorbent during the thermal desorption process. Furthermore, the enhanced thermal stability after TEP addition ensured lower degradation of amine groups during adsorption/desorption cycles.

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

    PubMed

    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. PMID:26374054

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

    PubMed

    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.

  17. Process for producing an activated carbon adsorbent with integral heat transfer apparatus

    NASA Technical Reports Server (NTRS)

    Jones, Jack A. (Inventor); Yavrouian, Andre H. (Inventor)

    1996-01-01

    A process for producing an integral adsorbent-heat exchanger apparatus useful in ammonia refrigerant heat pump systems. In one embodiment, the process wets an activated carbon particles-solvent mixture with a binder-solvent mixture, presses the binder wetted activated carbon mixture on a metal tube surface and thereafter pyrolyzes the mixture to form a bonded activated carbon matrix adjoined to the tube surface. The integral apparatus can be easily and inexpensively produced by the process in large quantities.

  18. Porous materials as high performance adsorbents for CO2 capture, gas separation and purification

    NASA Astrophysics Data System (ADS)

    Wang, Jun

    Global warming resulted from greenhouse gases emission has received a widespread attention. Among the greenhouse gases, CO2 contributes more than 60% to global warming due to its huge emission amount. The flue gas contains about 15% CO2 with N2 as the balance. If CO2 can be separated from flue gas, the benefit is not only reducing the global warming effect, but also producing pure CO2 as a very useful industry raw material. Substantial progress is urgent to be achieved in an industrial process. Moreover, energy crisis is one of the biggest challenges for all countries due to the short life of fossil fuels, such as, petroleum will run out in 50 years and coal will run out in 150 years according to today's speed. Moreover, the severe pollution to the environment caused by burning fossil fuels requires us to explore sustainable, environment-friendly, and facile energy sources. Among several alternative energy sources, natural gas is one of the most promising alternative energy sources due to its huge productivity, abundant feed stock, and ease of generation. In order to realize a substantial adsorption process in industry, synthesis of new adsorbents or modification of existing adsorbent with improved properties has become the most critical issue. This dissertation reports systemic characterization and development of five serials of novel adsorbents with advanced adsorption properties. In chapter 2, nitrogen-doped Hypercross-linking Polymers (HCPs) have been synthesized successfully with non-carcinogenic chloromethyl methyl ether (CME) as the cross-linking agent within a single step. Texture properties, surface morphology, CO2/N2 selectivity, and adsorption heat have been presented and demonstrated properly. A comprehensive discussion on factors that affect the CO2 adsorption and CO2/N 2 separation has also been presented. It was found that high micropore proportion and N-content could effectively enhance CO2 uptake and CO2/N2 separation selectivity. In chapter 3, a

  19. Porous materials as high performance adsorbents for CO2 capture, gas separation and purification

    NASA Astrophysics Data System (ADS)

    Wang, Jun

    Global warming resulted from greenhouse gases emission has received a widespread attention. Among the greenhouse gases, CO2 contributes more than 60% to global warming due to its huge emission amount. The flue gas contains about 15% CO2 with N2 as the balance. If CO2 can be separated from flue gas, the benefit is not only reducing the global warming effect, but also producing pure CO2 as a very useful industry raw material. Substantial progress is urgent to be achieved in an industrial process. Moreover, energy crisis is one of the biggest challenges for all countries due to the short life of fossil fuels, such as, petroleum will run out in 50 years and coal will run out in 150 years according to today's speed. Moreover, the severe pollution to the environment caused by burning fossil fuels requires us to explore sustainable, environment-friendly, and facile energy sources. Among several alternative energy sources, natural gas is one of the most promising alternative energy sources due to its huge productivity, abundant feed stock, and ease of generation. In order to realize a substantial adsorption process in industry, synthesis of new adsorbents or modification of existing adsorbent with improved properties has become the most critical issue. This dissertation reports systemic characterization and development of five serials of novel adsorbents with advanced adsorption properties. In chapter 2, nitrogen-doped Hypercross-linking Polymers (HCPs) have been synthesized successfully with non-carcinogenic chloromethyl methyl ether (CME) as the cross-linking agent within a single step. Texture properties, surface morphology, CO2/N2 selectivity, and adsorption heat have been presented and demonstrated properly. A comprehensive discussion on factors that affect the CO2 adsorption and CO2/N 2 separation has also been presented. It was found that high micropore proportion and N-content could effectively enhance CO2 uptake and CO2/N2 separation selectivity. In chapter 3, a

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

    SciTech Connect

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

    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.

  1. Preparation of magnetic metal organic frameworks adsorbent modified with mercapto groups for the extraction and analysis of lead in food samples by flame atomic absorption spectrometry.

    PubMed

    Wang, Yang; Chen, Huanhuan; Tang, Jie; Ye, Guiqin; Ge, Huali; Hu, Xiaoya

    2015-08-15

    A novel magnetic metal organic frameworks adsorbent modified with mercapto groups was synthesized and developed for extraction and spectrophotometric determination of trace lead. The adsorbent was characterized by Fourier transforms infrared spectrometer, X-ray diffraction, scanning electron microscopy and vibrating sample magnetometry. The results indicated the adsorbents exhibited high adsorption capacities for lead due to the chelation mechanism between metal cations and mercapto groups. Meanwhile, the lead sorption onto the adsorbents could be easily separated from aqueous solution using a magnetic separation method. Under the optimal conditions, a linear calibration curve in the range from 1 to 20 μg L(-1) was achieved with an enrichment factor of 100. The limits of detection and quantitation for lead were found to be 0.29 and 0.97 μg L(-1), respectively. The developed method was successfully applied to the determination of trace amounts of lead in food samples and certified reference material with satisfactory results. PMID:25794739

  2. Preparation of magnetic metal organic frameworks adsorbent modified with mercapto groups for the extraction and analysis of lead in food samples by flame atomic absorption spectrometry.

    PubMed

    Wang, Yang; Chen, Huanhuan; Tang, Jie; Ye, Guiqin; Ge, Huali; Hu, Xiaoya

    2015-08-15

    A novel magnetic metal organic frameworks adsorbent modified with mercapto groups was synthesized and developed for extraction and spectrophotometric determination of trace lead. The adsorbent was characterized by Fourier transforms infrared spectrometer, X-ray diffraction, scanning electron microscopy and vibrating sample magnetometry. The results indicated the adsorbents exhibited high adsorption capacities for lead due to the chelation mechanism between metal cations and mercapto groups. Meanwhile, the lead sorption onto the adsorbents could be easily separated from aqueous solution using a magnetic separation method. Under the optimal conditions, a linear calibration curve in the range from 1 to 20 μg L(-1) was achieved with an enrichment factor of 100. The limits of detection and quantitation for lead were found to be 0.29 and 0.97 μg L(-1), respectively. The developed method was successfully applied to the determination of trace amounts of lead in food samples and certified reference material with satisfactory results.

  3. NASA Applications of Molecular Adsorber Coatings

    NASA Technical Reports Server (NTRS)

    Abraham, Nithin S.

    2015-01-01

    The Molecular Adsorber Coating (MAC) is a new, innovative technology that was developed to reduce the risk of molecular contamination on spaceflight applications. Outgassing from materials, such as plastics, adhesives, lubricants, silicones, epoxies, and potting compounds, pose a significant threat to the spacecraft and the lifetime of missions. As a coating made of highly porous inorganic materials, MAC offers impressive adsorptive capabilities that help capture and trap contaminants. Past research efforts have demonstrated the coating's promising adhesion performance, optical properties, acoustic durability, and thermal stability. These results advocate its use near or on surfaces that are targeted by outgassed materials, such as internal optics, electronics, detectors, baffles, sensitive instruments, thermal control coatings, and vacuum chamber test environments. The MAC technology has significantly progressed in development over the recent years. This presentation summarizes the many NASA spaceflight applications of MAC and how the coatings technology has been integrated as a mitigation tool for outgassed contaminants. For example, this sprayable paint technology has been beneficial for use in various vacuum chambers for contamination control and hardware bake-outs. The coating has also been used in small instrument cavities within spaceflight instrument for NASA missions.

  4. Bowl inversion of surface-adsorbed sumanene.

    PubMed

    Jaafar, Rached; Pignedoli, Carlo A; Bussi, Giovanni; Aït-Mansour, Kamel; Groening, Oliver; Amaya, Toru; Hirao, Toshikazu; Fasel, Roman; Ruffieux, Pascal

    2014-10-01

    Bowl-shaped π-conjugated compounds offer the possibility to study curvature-dependent host-guest interactions and chemical reactivity in ideal model systems. For surface-adsorbed π bowls, however, only conformations with the bowl opening pointing away from the surface have been observed so far. Here we show for sumanene on Ag(111) that both bowl-up and bowl-down conformations can be stabilized. Analysis of the molecular layer as a function of coverage reveals an unprecedented structural phase transition involving a bowl inversion of one-third of the molecules. On the basis of scanning tunneling microscopy (STM) and complementary atomistic simulations, we develop a model that describes the observed phase transition in terms of a subtle interplay between inversion-dependent adsorption energies and intermolecular interactions. In addition, we explore the coexisting bowl-up and -down conformations with respect to host-guest binding of methane. STM reveals a clear energetic preference for methane binding to the concave face of sumanene. PMID:25181621

  5. Sleep and Delinquency: Does the Amount of Sleep Matter?

    ERIC Educational Resources Information Center

    Clinkinbeard, Samantha S.; Simi, Pete; Evans, Mary K.; Anderson, Amy L.

    2011-01-01

    Sleep, a key indicator of health, has been linked to a variety of indicators of well-being such that people who get an adequate amount generally experience greater well-being. Further, a lack of sleep has been linked to a wide range of negative developmental outcomes, yet sleep has been largely overlooked among researchers interested in adolescent…

  6. 45 CFR 32.8 - Amounts withheld.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... debtor's disposable pay exceeds an amount equivalent to thirty times the minimum wage. See 29 CFR 870.10... 45 Public Welfare 1 2011-10-01 2011-10-01 false Amounts withheld. 32.8 Section 32.8 Public Welfare DEPARTMENT OF HEALTH AND HUMAN SERVICES GENERAL ADMINISTRATION ADMINISTRATIVE WAGE GARNISHMENT § 32.8...

  7. 20 CFR 617.45 - Amount.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... weight authorized under the Federal travel regulations (see 41 CFR part 101-7), between such locations... 20 Employees' Benefits 3 2011-04-01 2011-04-01 false Amount. 617.45 Section 617.45 Employees... WORKERS UNDER THE TRADE ACT OF 1974 Relocation Allowances § 617.45 Amount. (a) Items allowable. The...

  8. 12 CFR 313.95 - Amounts withheld.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... thirty times the minimum wage. See 29 CFR 870.10. (c) When a debtor's pay is subject to withholding... 12 Banks and Banking 4 2011-01-01 2011-01-01 false Amounts withheld. 313.95 Section 313.95 Banks... CORPORATE DEBT COLLECTION Administrative Wage Garnishment § 313.95 Amounts withheld. (a) Upon receipt of...

  9. 20 CFR 617.34 - Amount.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... the Federal travel regulations (see 41 CFR part 101-7) for the locality where the job search is... travel regulations (see 41 CFR part 101-7) for such roundtrip travel by the usual route from the... WORKERS UNDER THE TRADE ACT OF 1974 Job Search Allowances § 617.34 Amount. (a) Computation. The amount...

  10. 20 CFR 617.34 - Amount.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... the Federal travel regulations (see 41 CFR part 101-7) for the locality where the job search is... travel regulations (see 41 CFR part 101-7) for such roundtrip travel by the usual route from the... WORKERS UNDER THE TRADE ACT OF 1974 Job Search Allowances § 617.34 Amount. (a) Computation. The amount...

  11. 20 CFR 617.34 - Amount.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... the Federal travel regulations (see 41 CFR part 101-7) for the locality where the job search is... travel regulations (see 41 CFR part 101-7) for such roundtrip travel by the usual route from the... WORKERS UNDER THE TRADE ACT OF 1974 Job Search Allowances § 617.34 Amount. (a) Computation. The amount...

  12. 33 CFR 135.203 - Amount required.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 33 Navigation and Navigable Waters 2 2012-07-01 2012-07-01 false Amount required. 135.203 Section 135.203 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED... Financial Responsibility for Offshore Facilities § 135.203 Amount required. (a) Each facility that is...

  13. 33 CFR 135.203 - Amount required.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 33 Navigation and Navigable Waters 2 2014-07-01 2014-07-01 false Amount required. 135.203 Section 135.203 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED... Financial Responsibility for Offshore Facilities § 135.203 Amount required. (a) Each facility that is...

  14. 23 CFR 1335.8 - Grant amounts.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 23 Highways 1 2011-04-01 2011-04-01 false Grant amounts. 1335.8 Section 1335.8 Highways NATIONAL HIGHWAY TRAFFIC SAFETY ADMINISTRATION, DEPARTMENT OF TRANSPORTATION STATE HIGHWAY SAFETY DATA IMPROVEMENTS § 1335.8 Grant amounts. (a) Start-up grant. A State that qualifies for a start-up grant under §...

  15. 23 CFR 1335.8 - Grant amounts.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 23 Highways 1 2010-04-01 2010-04-01 false Grant amounts. 1335.8 Section 1335.8 Highways NATIONAL HIGHWAY TRAFFIC SAFETY ADMINISTRATION, DEPARTMENT OF TRANSPORTATION STATE HIGHWAY SAFETY DATA IMPROVEMENTS § 1335.8 Grant amounts. (a) Start-up grant. A State that qualifies for a start-up grant under §...

  16. 13 CFR 400.202 - Loan amount.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ....202 Business Credit and Assistance EMERGENCY STEEL GUARANTEE LOAN BOARD EMERGENCY STEEL GUARANTEE LOAN PROGRAM Steel Guarantee Loans § 400.202 Loan amount. (a) The aggregate amount of loan principal guaranteed under this Program to a single Qualified Steel Company may not exceed $ 250 million. (b) Of...

  17. 13 CFR 400.202 - Loan amount.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ....202 Business Credit and Assistance EMERGENCY STEEL GUARANTEE LOAN BOARD EMERGENCY STEEL GUARANTEE LOAN PROGRAM Steel Guarantee Loans § 400.202 Loan amount. (a) The aggregate amount of loan principal guaranteed under this Program to a single Qualified Steel Company may not exceed $ 250 million. (b) Of...

  18. 13 CFR 400.202 - Loan amount.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ....202 Business Credit and Assistance EMERGENCY STEEL GUARANTEE LOAN BOARD EMERGENCY STEEL GUARANTEE LOAN PROGRAM Steel Guarantee Loans § 400.202 Loan amount. (a) The aggregate amount of loan principal guaranteed under this Program to a single Qualified Steel Company may not exceed $ 250 million. (b) Of...

  19. 13 CFR 400.202 - Loan amount.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ....202 Business Credit and Assistance EMERGENCY STEEL GUARANTEE LOAN BOARD EMERGENCY STEEL GUARANTEE LOAN PROGRAM Steel Guarantee Loans § 400.202 Loan amount. (a) The aggregate amount of loan principal guaranteed under this Program to a single Qualified Steel Company may not exceed $ 250 million. (b) Of...

  20. 13 CFR 400.202 - Loan amount.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ....202 Business Credit and Assistance EMERGENCY STEEL GUARANTEE LOAN BOARD EMERGENCY STEEL GUARANTEE LOAN PROGRAM Steel Guarantee Loans § 400.202 Loan amount. (a) The aggregate amount of loan principal guaranteed under this Program to a single Qualified Steel Company may not exceed $ 250 million. (b) Of...

  1. 31 CFR 50.95 - Final amount.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 31 Money and Finance: Treasury 1 2013-07-01 2013-07-01 false Final amount. 50.95 Section 50.95 Money and Finance: Treasury Office of the Secretary of the Treasury TERRORISM RISK INSURANCE PROGRAM Cap on Annual Liability § 50.95 Final amount. (a) Treasury shall determine if, as a final...

  2. 31 CFR 50.95 - Final amount.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 31 Money and Finance: Treasury 1 2014-07-01 2014-07-01 false Final amount. 50.95 Section 50.95 Money and Finance: Treasury Office of the Secretary of the Treasury TERRORISM RISK INSURANCE PROGRAM Cap on Annual Liability § 50.95 Final amount. (a) Treasury shall determine if, as a final...

  3. 31 CFR 50.95 - Final amount.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 31 Money and Finance: Treasury 1 2012-07-01 2012-07-01 false Final amount. 50.95 Section 50.95 Money and Finance: Treasury Office of the Secretary of the Treasury TERRORISM RISK INSURANCE PROGRAM Cap on Annual Liability § 50.95 Final amount. (a) Treasury shall determine if, as a final...

  4. Growth and Dissolution of Calcite in the Presence of Adsorbed Stearic Acid.

    PubMed

    Ricci, Maria; Segura, Juan José; Erickson, Blake W; Fantner, Georg; Stellacci, Francesco; Voïtchovsky, Kislon

    2015-07-14

    The interaction of organic molecules with the surface of calcite plays a central role in many geochemical, petrochemical, and industrial processes and in biomineralization. Adsorbed organics, typically fatty acids, can interfere with the evolution of calcite when immersed in aqueous solutions. Here we use atomic force microscopy in liquid to explore in real-time the evolution of the (1014) surface of calcite covered with various densities of stearic acid and exposed to different saline solutions. Our results show that the stearic acid molecules tend to act as "pinning points" on the calcite's surface and slow down the crystal's restructuring kinetics. Depending on the amount of material adsorbed, the organic molecules can form monolayers or bilayer islands that become embedded into the growing crystal. The growth process can also displaces the organic molecules and actively concentrate them into stacked multilayers. Our results provide molecular-level insights into the interplay between the adsorbed fatty acid molecules and the evolving calcite crystal, highlighting mechanisms that could have important implications for several biochemical and geochemical processes and for the oil industry.

  5. A Reliable Hybrid Adsorbent for Efficient Radioactive Cesium Accumulation from Contaminated Wastewater

    NASA Astrophysics Data System (ADS)

    Awual, Md. Rabiul; Yaita, Tsuyoshi; Miyazaki, Yuji; Matsumura, Daiju; Shiwaku, Hideaki; Taguchi, Tomitsugu

    2016-01-01

    Cesium (Cs) removal from nuclear liquid wastewater has become an emerging issue for safeguarding public health after the accident at the Fukushima Daiichi Nuclear Power Plant. A novel macrocyclic ligand of o-benzo-p-xylyl-22-crown-6-ether (OBPX22C6) was developed and successfully immobilized onto mesoporous silica for the preparation of hybrid adsorbent. The benzene ring π electron is the part of crown ether of OBPX22C6 for easy orientation of the macrocyclic compound for making the π electron donation with Cs complexation. The potential and feasibility of the hybrid adsorbent as being Cs selective was evaluated in terms of sensitivity, selectivity and reusability. The results clarified that the Cs removal process was rapid and reached saturation within a short time. Considering the effect of competitive ions, sodium (Na) did not markedly affect the Cs adsorption whereas potassium (K) was slightly affected due to the similar ionic radii. However, the oxygen in long ethylene glycol chain in OBPX22C6 was expected to show strong coordination, including Cs-π interaction with Cs even in the presence of the high amount of K and Na. Due to its high selectivity and reusability, significant volume reduction is expected as this promising hybrid adsorbent is used for Cs removal in Fukushima wastewater.

  6. As(V) adsorption onto nanoporous titania adsorbents (NTAs): effects of solution composition.

    PubMed

    Han, Dong Suk; Batchelor, Bill; Park, Sung Hyuk; Abdel-Wahab, Ahmed

    2012-08-30

    This study has focused on developing two nanoporous titania adsorbents (NTA) to enhance removal efficiency of adsorption process for As(V) by characterizing the effects of pH and phosphate concentration on their sorption capacities and behaviors. One type of adsorbent is a mesoporous titania (MT) solid phase and the other is group of a highly ordered mesoporous silica solids (SBA-15) that can incorporate different levels of reactive titania sorption sites. Microscopic analysis showed that Ti((25))-SBA-15 (Ti/SBA=0.25 g/g) had titania nanostructured mesopores that do not rupture the highly ordered hexagonal silica framework. However, MT has disordered, wormhole-like mesopores that are caused by interparticle porosity. Adsorption experiments showed that Ti((25))-SBA-15 had a greater sorption capacity for As(V) than did Ti((15))-SBA-15 or Ti((35))-SBA-15 and the amount of As(V) adsorbed generally decreased as pH increased. Higher removal of As(V) was observed with Ti((25))-SBA-15 than with MT at pH 4, but MT had higher removals at higher pH (7, 9.5), even though MT has a lower specific surface area. However, in the presence of phosphate, MT showed higher removal of As(V) at low pH rather than did Ti((25))-SBA-15. As expected, the NTAs showed very fast sorption kinetics, but they followed a bi-phasic sorption pattern.

  7. Adsorption / Desorption Behavior of Water Vapor in an Adsorbent Desiccant Rotor

    NASA Astrophysics Data System (ADS)

    Tsujiguchi, Takuya; Kodama, Akio

    Adsorption / desorption behavior of water vapor onto desiccant rotor has been investigated to improve the desiccant cooling system by means of computer simulation. In this paper, we paid attention to the relationship between the equilibrium amount of water adsorbed onto the desiccant material and the relative humidity, that is adsorption isotherm as a principal characteristic feature of adsorbent. Considering actual adsorbents, five types of adsorption isotherms were assumed to clarify the influence of adsorption isotherm on the dehumidifying performance. After the investigation on the influences of some operating conditions on the dehumidifying performance at each selected adsorption isotherm, it was found that higher dehumidifying performance and reduction of length of desiccant rotor could be achieved by selecting appropriate adsorption isotherm. It was also predicted that S-shaped adsorption isotherm which is raised sharply at relative humidity around 15 % could produce the lowest air humidity at regeneration air temperature 80 °C. Moreover influence of the intraparticle diffusion coefficient which significantly influence on the adsorption / desorption rate was discussed choosing two adsorption isotherm from the above five isotherms. It seems that effective range of the intraparticle diffusion coefficient for the significant improvement of the dehumidifying performance was strongly influenced by the shape of adsorption isotherm.

  8. A Reliable Hybrid Adsorbent for Efficient Radioactive Cesium Accumulation from Contaminated Wastewater.

    PubMed

    Awual, Md Rabiul; Yaita, Tsuyoshi; Miyazaki, Yuji; Matsumura, Daiju; Shiwaku, Hideaki; Taguchi, Tomitsugu

    2016-01-28

    Cesium (Cs) removal from nuclear liquid wastewater has become an emerging issue for safeguarding public health after the accident at the Fukushima Daiichi Nuclear Power Plant. A novel macrocyclic ligand of o-benzo-p-xylyl-22-crown-6-ether (OBPX22C6) was developed and successfully immobilized onto mesoporous silica for the preparation of hybrid adsorbent. The benzene ring π electron is the part of crown ether of OBPX22C6 for easy orientation of the macrocyclic compound for making the π electron donation with Cs complexation. The potential and feasibility of the hybrid adsorbent as being Cs selective was evaluated in terms of sensitivity, selectivity and reusability. The results clarified that the Cs removal process was rapid and reached saturation within a short time. Considering the effect of competitive ions, sodium (Na) did not markedly affect the Cs adsorption whereas potassium (K) was slightly affected due to the similar ionic radii. However, the oxygen in long ethylene glycol chain in OBPX22C6 was expected to show strong coordination, including Cs-π interaction with Cs even in the presence of the high amount of K and Na. Due to its high selectivity and reusability, significant volume reduction is expected as this promising hybrid adsorbent is used for Cs removal in Fukushima wastewater.

  9. A Reliable Hybrid Adsorbent for Efficient Radioactive Cesium Accumulation from Contaminated Wastewater

    PubMed Central

    Awual, Md. Rabiul; Yaita, Tsuyoshi; Miyazaki, Yuji; Matsumura, Daiju; Shiwaku, Hideaki; Taguchi, Tomitsugu

    2016-01-01

    Cesium (Cs) removal from nuclear liquid wastewater has become an emerging issue for safeguarding public health after the accident at the Fukushima Daiichi Nuclear Power Plant. A novel macrocyclic ligand of o-benzo-p-xylyl-22-crown-6-ether (OBPX22C6) was developed and successfully immobilized onto mesoporous silica for the preparation of hybrid adsorbent. The benzene ring π electron is the part of crown ether of OBPX22C6 for easy orientation of the macrocyclic compound for making the π electron donation with Cs complexation. The potential and feasibility of the hybrid adsorbent as being Cs selective was evaluated in terms of sensitivity, selectivity and reusability. The results clarified that the Cs removal process was rapid and reached saturation within a short time. Considering the effect of competitive ions, sodium (Na) did not markedly affect the Cs adsorption whereas potassium (K) was slightly affected due to the similar ionic radii. However, the oxygen in long ethylene glycol chain in OBPX22C6 was expected to show strong coordination, including Cs-π interaction with Cs even in the presence of the high amount of K and Na. Due to its high selectivity and reusability, significant volume reduction is expected as this promising hybrid adsorbent is used for Cs removal in Fukushima wastewater. PMID:26818070

  10. A Reliable Hybrid Adsorbent for Efficient Radioactive Cesium Accumulation from Contaminated Wastewater.

    PubMed

    Awual, Md Rabiul; Yaita, Tsuyoshi; Miyazaki, Yuji; Matsumura, Daiju; Shiwaku, Hideaki; Taguchi, Tomitsugu

    2016-01-01

    Cesium (Cs) removal from nuclear liquid wastewater has become an emerging issue for safeguarding public health after the accident at the Fukushima Daiichi Nuclear Power Plant. A novel macrocyclic ligand of o-benzo-p-xylyl-22-crown-6-ether (OBPX22C6) was developed and successfully immobilized onto mesoporous silica for the preparation of hybrid adsorbent. The benzene ring π electron is the part of crown ether of OBPX22C6 for easy orientation of the macrocyclic compound for making the π electron donation with Cs complexation. The potential and feasibility of the hybrid adsorbent as being Cs selective was evaluated in terms of sensitivity, selectivity and reusability. The results clarified that the Cs removal process was rapid and reached saturation within a short time. Considering the effect of competitive ions, sodium (Na) did not markedly affect the Cs adsorption whereas potassium (K) was slightly affected due to the similar ionic radii. However, the oxygen in long ethylene glycol chain in OBPX22C6 was expected to show strong coordination, including Cs-π interaction with Cs even in the presence of the high amount of K and Na. Due to its high selectivity and reusability, significant volume reduction is expected as this promising hybrid adsorbent is used for Cs removal in Fukushima wastewater. PMID:26818070

  11. Fabrication of Micro-Lens Array using a Chemically Adsorbed Monomolecular Layer

    NASA Astrophysics Data System (ADS)

    Okada, Kazushi; Oohira, Fumikazu; Hosogi, Maho; Hashiguchi, Gen; Mihara, Yutaka; Ogawa, Kazufumi; Shiwaku, Kazuya

    We proposed a new method of patterning a chemically adsorbed monomolecular layer on the substrate and then dropping UV cure material to form a lens shape using oil repellent effect of this film. The curvature radius of the lens was controlled by the amount of the dropped UV cure material. Using this method, a micro-lens array of various radiuses was fabricated. The formed micro-lens array shapes are transferred by the electro-plating and then the micro dies are fabricated, which are used for molding the plastic lens array. The optical characteristic of the molded micro-lens was evaluated.

  12. Hollow mesoporous carbon spheres with magnetic cores and their performance as separable bilirubin adsorbents.

    PubMed

    Guo, Limin; Cui, Xiangzhi; Li, Yongsheng; He, Qianjun; Zhang, Lingxia; Bu, Wenbo; Shi, Jianlin

    2009-09-01

    Hollow mesoporous carbon spheres with magnetic cores are directly replicated from hollow mesoporous aluminosilicate spheres with hematite cores by a simple incipient-wetness impregnation technique. The amount of magnetic cores and the saturation magnetization value can be easily tuned by changing the concentration of iron nitrate solution used in the synthesis procedure. As-prepared hollow mesoporous carbon spheres with magnetic cores are used as separable bilirubin adsorbents and show very good adsorptive properties. The characteristics of as-prepared composites are examined by XRD, N(2) sorption, TEM, vibrating-sample magnetometry, and UV/Vis spectroscopy. PMID:19582733

  13. Development of Composite Adsorbents for LLW Treatment and Their Adsorption Properties for Cs and Sr - 13127

    SciTech Connect

    Susa, Shunsuke; Mimura, Hitoshi; Ito, Yoshiyuki; Saito, Yasuo

    2013-07-01

    In this study, the composite adsorbents (KCoFC-NM (NM: natural mordenite), KCoFC-SG (SG: porous silica gel), AMP-SG and so on) were prepared by impregnation-precipitation methods. As for the distribution properties, the largest K{sub d,Cs} value of 3.8 x 10{sup 4} cm{sup 3}/g was obtained for KCoFC-SG (Davi.) composite. KCoFC-SG (NH, MB5D) and T-KCFC also had relatively large K{sub d,Cs} values above 1.0 x 10{sup 4} cm{sup 3}/g. The uptake rate of Cs{sup +} ions was examined by batch method. KCoFC-SG (NH, MB5D) and AMP-SG (Davi.) had relatively large uptake rate of Cs{sup +}, and the uptake attained equilibrium within 1 h. The maximum uptake capacity of Cs{sup +} ions was estimated to be above 0.5 mmol/g for KCoFC-NM and KCoFC-CP composites. KCoFC-X composite had a relatively large uptake capacity of Cs{sup +} ions (0.23 mmol/g > 0.17 mmol/g (T-KCFC)) and this composite also had a selectivity towards Sr{sup 2+} ions; KCoFC-X is effective adsorbent for both Cs{sup +} and Sr{sup 2+} ions. The largest value of K{sub d,Sr} was estimated to be 218 cm{sup 3}/g for titanic acid-PAN. Titanic acid-PAN had the largest uptake rate of Sr{sup 2+} ions, and the uptake attained equilibrium within 8 h. Adsorbability of other nuclides was further examined by batch method. All adsorbents had adsorbability for Rb{sup +} and RuNO{sup 3+} ions. KCoFC-SG (NH), KCoFC-CP and T-KCFC had higher selectivity towards Cs{sup +} than other adsorbents; these adsorbents had adsorbability to Cs{sup +} ions even in the presence of Ba{sup 2+}, Ca{sup 2+} and Mg{sup 2+} ions. The separation factor of K{sub d,Sr}/K{sub d,Ba} for titanic acid-PAN was about 1, indicating that the K{sub d,Sr} for titanic acid-PAN tends to decrease with Ba{sup 2+} concentration. As for the breakthrough properties, the largest 5 % breakpoint and 5 % breakthrough capacity of Cs{sup +} ions were estimated to be 47.1 cm{sup 3} and 0.07 mmol/g for the column of KCoFC-SG (NH), respectively. The order of 5 % breakthrough capacity

  14. Carbon dioxide pressure swing adsorption process using modified alumina adsorbents

    DOEpatents

    Gaffney, T.R.; Golden, T.C.; Mayorga, S.G.; Brzozowski, J.R.; Taylor, F.W.

    1999-06-29

    A pressure swing adsorption process for absorbing CO[sub 2] from a gaseous mixture containing CO[sub 2] comprises introducing the gaseous mixture at a first pressure into a reactor containing a modified alumina adsorbent maintained at a temperature ranging from 100 C and 500 C to adsorb CO[sub 2] to provide a CO[sub 2] laden alumina adsorbent and a CO[sub 2] depleted gaseous mixture and contacting the CO[sub 2] laden adsorbent with a weakly adsorbing purge fluid at a second pressure which is lower than the first pressure to desorb CO[sub 2] from the CO[sub 2] laden alumina adsorbent. The modified alumina adsorbent which is formed by depositing a solution having a pH of 3.0 or more onto alumina and heating the alumina to a temperature ranging from 100 C and 600 C, is not degraded by high concentrations of water under process operating conditions. 1 fig.

  15. Carbon dioxide pressure swing adsorption process using modified alumina adsorbents

    DOEpatents

    Gaffney, Thomas Richard; Golden, Timothy Christopher; Mayorga, Steven Gerard; Brzozowski, Jeffrey Richard; Taylor, Fred William

    1999-01-01

    A pressure swing adsorption process for absorbing CO.sub.2 from a gaseous mixture containing CO.sub.2 comprising introducing the gaseous mixture at a first pressure into a reactor containing a modified alumina adsorbent maintained at a temperature ranging from 100.degree. C. and 500.degree. C. to adsorb CO.sub.2 to provide a CO.sub.2 laden alumina adsorbent and a CO.sub.2 depleted gaseous mixture and contacting the CO.sub.2 laden adsorbent with a weakly adsorbing purge fluid at a second pressure which is lower than the first pressure to desorb CO.sub.2 from the CO.sub.2 laden alumina adsorbent. The modified alumina adsorbent which is formed by depositing a solution having a pH of 3.0 or more onto alumina and heating the alumina to a temperature ranging from 100.degree. C. and 600.degree. C., is not degraded by high concentrations of water under process operating conditions.

  16. Novel adhesion properties of irreversibly adsorbed polymer chains

    NASA Astrophysics Data System (ADS)

    Chen, Zhizhao; Sen, Mani; Cheung, Justin; Barkley, Deborah; Jiang, Naisheng; Zeng, Wenduo; Endoh, Maya K.; Koga, Tadanori

    The stability of thin polymer films on solids is of vital interest in traditional technologies and in new emerging nanotechnologies. We recently found that nanoscale structures of polymer chains adsorbed onto a silicon (Si) substrate (``adsorbed nanolayers'') play a crucial role in the thermal stability of the film. To understand the adhesion mechanism at the adsorbed polymer-free polymer interface, we mimicked the interface by preparing bilayers where a 200 nm-thick polymer film and an adsorbed nanolayer, both prepared on Si, were pressed together at high temperature. The bilayers were then subjected to an adhesion test by measuring the critical normal force required to separate the two films. Polystyrene was used as a model. The results are intriguing as they show an absence of adhesion between the ``flattened'' adsorbed chains, which lie flat on the solid, and the chemically identical free chains. On the other hand, the ``loosely adsorbed'' polymer chains, which are formed as a result of limited adsorption space on the solid surface, do display a degree of adhesion with the bulk polymer. We postulate that the loosely adsorbed chains act as ``connectors'' which promote adhesion effectively across the solid-polymer interface. We acknowledge the financial support from NSF Grant No. CMMI-1332499.

  17. Methane Recovery from Gaseous Mixtures Using Carbonaceous Adsorbents

    NASA Astrophysics Data System (ADS)

    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. Efficient adsorbents of nanoporous aluminosilicate monoliths for organic dyes from aqueous solution.

    PubMed

    El-Safty, Sherif A; Shahat, Ahmed; Awual, Md Rabiul

    2011-07-01

    Growing public awareness on the potential risk to humans of toxic chemicals in the environment has generated demand for new and improved methods for toxicity assessment and removal, rational means for health risk estimation. With the aim of controlling nanoscale adsorbents for functionality in molecular sieving of organic pollutants, we fabricated cubic Im3m mesocages with uniform entrance and large cavity pores of aluminosilicates as highly promising candidates for the colorimetric monitoring of organic dyes in an aqueous solution. However, a feasible control over engineering of three-dimensional (3D) mesopore cage structures with uniform entrance (~5 nm) and large cavity (~10 nm) allowed the development of nanoadsorbent membranes as a powerful tool for large-quantity and high-speed (in minutes) adsorption/removal of bulk molecules such as organic dyes. Incorporation of high aluminum contents (Si/Al=1) into 3D cubic Im3m cage mesoporous silica monoliths resulted in small, easy-to-use optical adsorbent strips. In such adsorption systems, natural surfaces of active acid sites of aluminosilicate strips strongly induced both physical adsorption of chemically responsive dyes and intraparticle diffusion into cubic Im3m mesocage monoliths. Results likewise indicated that although aluminosilicate strips with low Si/Al ratios exhibit distortion in pore ordering and decrease in surface area and pore volume, enhancement of both molecular converges and intraparticle diffusion onto the network surfaces and into the pore architectures of adsorbent membranes was achieved. Moreover, 3D mesopore cage adsorbents are reversible, offering potential for multiple adsorption assays.

  19. Exciton Splitting of Adsorbed and Free 4-Nitroazobenzene Dimers: A Quantum Chemical Study.

    PubMed

    Titov, Evgenii; Saalfrank, Peter

    2016-05-19

    Molecular photoswitches such as azobenzenes, which undergo photochemical trans ↔ cis isomerizations, are often mounted for possible applications on a surface and/or surrounded by other switches, for example, in self-assembled monolayers. This may suppress the isomerization cross section due to possible steric reasons, or, as recently speculated, by exciton coupling to neighboring switches, leading to ultrafast electronic quenching (Gahl et al., J. Am. Chem. Soc. 2010, 132, 1831). The presence of exciton coupling has been anticipated from a blue shift of the optical absorption band, compared to molecules in solution. From the theory side the need arises to properly analyze and quantify the change of absorption spectra of interacting and adsorbed switches. In particular, suitable methods should be identified, and effects of intermolecule and molecule-surface interactions on spectra should be disentangled. In this paper by means of time-dependent Hartree-Fock (TD-HF), various flavors of time-dependent density functional theory (TD-DFT), and the correlated wave function based coupled-cluster (CC2) method we investigated the 4-nitroazobenzene molecule as an example: The low-lying singlet excited states in the isolated trans monomer and dimer as well as their composites with a silicon pentamantane nanocluster, which serves also as a crude model for a silicon surface, were determined. As most important results we found that (i) HF, CC2, range-separated density functionals, or global hybrids with large amount of exact exchange are able to describe exciton (Davydov) splitting properly, while hybrids with small amount of exact exchange fail producing spurious charge transfer. (ii) The exciton splitting in a free dimer would lead to a blue shift of the absorption signal; however, this effect is almost nullified or even overcompensated by the shift arising from van der Waals interactions between the two molecules. (iii) Adsorption on the Si "surface" leads to a further

  20. Removal of microcystin-LR from drinking water using a bamboo-based charcoal adsorbent modified with chitosan.

    PubMed

    Zhang, Hangjun; Zhu, Guoying; Jia, Xiuying; Ding, Ying; Zhang, Mi; Gao, Qing; Hu, Ciming; Xu, Shuying

    2011-01-01

    A new kind of low-cost syntactic adsorbent from bamboo charcoal and chitosan was developed for the removal of microcystin-LR from drinking water. Removal efficiency was higher for the syntactic adsorbent when the amount of bamboo charcoal was increased. The optimum dose ratio of bamboo charcoal to chitosan was 6:4, and the optimum amount was 15 mg/L; equilibrium time was 6 hr. The adsorption isotherm was non-linear and could be simulated by the Freundlich model (R2 = 0.9337). Adsorption efficiency was strongly affected by pH and natural organic matter (NOM). Removal efficiency was 16% higher at pH 3 than at pH 9. Efficiency rate was reduced by 15% with 25 mg/L NOM (UV254 = 0.089 cm(-1)) in drinking water. This study demonstrated that the bamboo charcoal modified with chitosan can effectively remove microcystin-LR from drinking water.

  1. Surface enhanced Raman scattering of pyrazole adsorbed on silver colloids

    NASA Astrophysics Data System (ADS)

    Muniz-Miranda, Maurizio; Neto, Natale; Sbrana, Giuseppe

    1999-05-01

    SERS spectra of pyrazole adsorbed on silver hydrosol at different pH values and on silver colloidal substrate deposited on filters were obtained and interpreted on the basis of the existence of three forms in equilibrium, cationic, neutral and anionic. SERS data indicate that the neutral molecule is preferentially adsorbed in acidic environment, pyrazolide anion is instead favoured over all the other pH values. Addition of chloride anions induces the formation of reaction products when pyrazole is adsorbed on silver hydrosols, while this effect is missing on dry silver substrate.

  2. Synthesis of adsorbents with dendronic structures for protein hydrophobic interaction chromatography.

    PubMed

    Mata-Gómez, Marco A; Yaman, Sena; Valencia-Gallegos, Jesus A; Tari, Canan; Rito-Palomares, Marco; González-Valdez, José

    2016-04-22

    Here, we introduced a new technology based on the incorporation of dendrons-branched chemical structures-onto supports for synthesis of HIC adsorbents. In doing so we studied the synthesis and performance of these novel HIC dendron-based adsorbents. The adsorbents were synthesized in a facile two-step reaction. First, Sepharose 4FF (R) was chemically modified with polyester dendrons of different branching degrees i.e. third (G3) or fifth (G5) generations. Then, butyl-end valeric acid ligands were coupled to dendrons via ester bond formation. UV-vis spectrophotometry and FTIR analyses of the modified resins confirmed the presence of the dendrons and their ligands on them. Inclusion of dendrons allowed the increment of ligand density, 82.5 ± 11 and 175.6 ± 5.7 μmol ligand/mL resin for RG3 and RG5, respectively. Static adsorption capacity of modified resins was found to be ∼ 60 mg BSA/mL resin. Interestingly, dynamic binding capacity was higher at high flow rates, 62.5 ± 0.8 and 58.0 ± 0.5mg/mL for RG3 and RG5, respectively. RG3 was able to separate lipase, β-lactoglobulin and α-chymotrypsin selectively as well as fractionating of a whole proteome from yeast. This innovative technology will improve the existing HIC resin synthesis methods. It will also allow the reduction of the amount of adsorbent used in a chromatographic procedure and thus permit the use of smaller columns resulting in faster processes. Furthermore, this method could potentially be considered as a green technology since both, dendrons and ligands, are formed by ester bonds that are more biodegradable allowing the disposal of used resin waste in a more ecofriendly manner when compared to other exiting resins.

  3. Synthesis of adsorbents with dendronic structures for protein hydrophobic interaction chromatography.

    PubMed

    Mata-Gómez, Marco A; Yaman, Sena; Valencia-Gallegos, Jesus A; Tari, Canan; Rito-Palomares, Marco; González-Valdez, José

    2016-04-22

    Here, we introduced a new technology based on the incorporation of dendrons-branched chemical structures-onto supports for synthesis of HIC adsorbents. In doing so we studied the synthesis and performance of these novel HIC dendron-based adsorbents. The adsorbents were synthesized in a facile two-step reaction. First, Sepharose 4FF (R) was chemically modified with polyester dendrons of different branching degrees i.e. third (G3) or fifth (G5) generations. Then, butyl-end valeric acid ligands were coupled to dendrons via ester bond formation. UV-vis spectrophotometry and FTIR analyses of the modified resins confirmed the presence of the dendrons and their ligands on them. Inclusion of dendrons allowed the increment of ligand density, 82.5 ± 11 and 175.6 ± 5.7 μmol ligand/mL resin for RG3 and RG5, respectively. Static adsorption capacity of modified resins was found to be ∼ 60 mg BSA/mL resin. Interestingly, dynamic binding capacity was higher at high flow rates, 62.5 ± 0.8 and 58.0 ± 0.5mg/mL for RG3 and RG5, respectively. RG3 was able to separate lipase, β-lactoglobulin and α-chymotrypsin selectively as well as fractionating of a whole proteome from yeast. This innovative technology will improve the existing HIC resin synthesis methods. It will also allow the reduction of the amount of adsorbent used in a chromatographic procedure and thus permit the use of smaller columns resulting in faster processes. Furthermore, this method could potentially be considered as a green technology since both, dendrons and ligands, are formed by ester bonds that are more biodegradable allowing the disposal of used resin waste in a more ecofriendly manner when compared to other exiting resins. PMID:27018188

  4. Mysterious Lattice Rotations in Adsorbed Monolayers

    NASA Astrophysics Data System (ADS)

    Diehl, Renee D.

    1997-03-01

    Lattice rotations due to a mismatch in structure have been observed in film growth for many years, probably beginning in the 1930's with the Nishiyama-Wasserman and Kurdjumov-Sachs orientations observed when fcc(111) films grow on bcc(110) surfaces, or vice versa. Early analysis of this problem was carried out with the aid of Moiré patterns and the observation that the preferred lattice orientations are those which maximize the Moiré fringe spacing. Later energy calculations indicated that the structures which were predicted by the the Moiré technique actually do correspond to energy minima. Epitaxial rotation in adsorbed monolayers is a conceptually simpler problem since in principle it involves only two planes of atoms, and it was first observed in 1977 for Ar on a graphite surface(C. G. Shaw, M. D. Chinn, S. C. Fain, Jr. Phys. Rev. Lett. 41 (1978) 955.). This observation came only a few months after a new theory, based on the expected elastic behavior of an overlayer, was developed by A. D. Novaco and J. P. McTague(A. D. Novaco and J. P. McTague, Phys. Rev. Lett. 38 (1977) 1286.), and the agreement with the experimental results was remarkable. It was later shown that a few symmetry principles similar to those used for the film growth studies sometimes can also predict the observed structures. However, the situation for incommensurate layers physisorbed on metal surfaces currently looks bleak. None of the existing theories or models appears to describe the experimental results. New data for physisorbed gases on metal surfaces will be presented, along with some half-baked (and probably wrong) ideas for what might be happening. This work was supported by NSF.

  5. Tunable magnetism in metal adsorbed fluorinated nanoporous graphene.

    PubMed

    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

  6. Tunable magnetism in metal adsorbed fluorinated nanoporous graphene

    DOE PAGES

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

    2016-08-24

    Developing nanostructures with tunable magnetic states is crucial for designing novel data storage and quantum information devices. Using density functional theory, we study 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 ismore » 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. In conclusion, our predictions open a promising way towards controlling the magnetic properties in graphene based spintronic and non-volatile memory devices.« less

  7. Tunable magnetism in metal adsorbed fluorinated nanoporous graphene

    NASA Astrophysics Data System (ADS)

    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.

  8. Tunable magnetism in metal adsorbed fluorinated nanoporous graphene.

    PubMed

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

    2016-08-24

    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.

  9. Tunable magnetism in metal adsorbed fluorinated nanoporous graphene

    PubMed Central

    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

  10. Volumetric Interpretation of Protein Adsorption: Ion-Exchange Adsorbent Capacity, Protein pI, and Interaction Energetics

    PubMed Central

    Noh, Hyeran; Yohe, Stefan; Vogler, Erwin A.

    2008-01-01

    Adsorption of lysozyme (Lys), human serum albumin (HSA), and immunoglobulin G (IgG) to anion- and cation-exchange resins is dominated by electrostatic interactions between protein and adsorbent. The solution-depletion method of measuring adsorption shows, however, that these proteins do not irreversibly adsorb to ion-exchange surfaces, even when the charge disparity between adsorbent and protein inferred from protein pI is large. Net-positively-charged Lys (pI = 11) and net-negatively-charged HSA (pI = 5.5) adsorb so strongly to sulfopropyl sepharose (SP; a negatively-charged, strong cation exchange resin, −0.22 mmol/mL exchange capacity) that both resist displacement by net-neutral IgG (pI = 7.0) in simultaneous adsorption-competition experiments. By contrast, IgG readily displaces both Lys and HSA adsorbed either to quarternary-ammonium sepharose (Q; a positively-charged, strong anion exchanger, + 0.22 mmol/mL exchange capacity) or octadecyl sepharose (ODS, a neutral hydrophobic resin, 0 mmol/mL exchange capacity). Thus it is concluded that adsorption results do not sensibly correlate with protein pI and that pI is actually a rather poor predictor of affinity for ion-exchange surfaces. Adsorption of Lys, HSA, and IgG to ion-exchange resins from stagnant solution leads to adsorbed multi-layers, into-or-onto which IgG adsorbs in adsorption-competition experiments. Comparison of adsorption to ion-exchange resins and neutral ODS leads to the conclusion that the apparent standard free-energy-of-adsorption ΔGadso of Lys, HSA, and IgG is not large in comparison to thermal energy due to energy-compensating interactions between water, protein, and ion-exchange surfaces that leaves a small net ΔGadso. Thus water is found to control protein adsorption to a full range of substratum types spanning hydrophobic (poorly water wettable) surfaces, hydrophilic surfaces bearing relatively-weak Lewis acid/base functionalities that wet with (hydrogen bond to) water but do not

  11. 45 CFR 32.8 - Amounts withheld.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... debtor's disposable pay exceeds an amount equivalent to thirty times the minimum wage. See 29 CFR 870.10... paragraph (b) of this section. The employer may use the SF-329C “Wage Garnishment Worksheet” to...

  12. 45 CFR 32.8 - Amounts withheld.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... debtor's disposable pay exceeds an amount equivalent to thirty times the minimum wage. See 29 CFR 870.10... paragraph (b) of this section. The employer may use the SF-329C “Wage Garnishment Worksheet” to...

  13. 45 CFR 32.8 - Amounts withheld.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... debtor's disposable pay exceeds an amount equivalent to thirty times the minimum wage. See 29 CFR 870.10... paragraph (b) of this section. The employer may use the SF-329C “Wage Garnishment Worksheet” to...

  14. 45 CFR 32.8 - Amounts withheld.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... debtor's disposable pay exceeds an amount equivalent to thirty times the minimum wage. See 29 CFR 870.10... paragraph (b) of this section. The employer may use the SF-329C “Wage Garnishment Worksheet” to...

  15. 20 CFR 340.2 - Amount recoverable.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... Employees' Benefits RAILROAD RETIREMENT BOARD REGULATIONS UNDER THE RAILROAD UNEMPLOYMENT INSURANCE ACT... amount of unemployment, sickness, or maternity benefits paid under the Railroad Unemployment Insurance..., unemployment, sickness or maternity benefits under any law other than the Railroad Unemployment Insurance...

  16. Dynamics of H2 adsorbed in porous materials as revealed by computational analysis of inelastic neutron scattering spectra.

    PubMed

    Pham, Tony; Forrest, Katherine A; Space, Brian; Eckert, Juergen

    2016-06-29

    The inelastic scattering of neutrons from adsorbed H2 is an effective and highly sensitive method for obtaining molecular level information on the type and nature of H2 binding sites in porous materials. While these inelastic neutron scattering (INS) spectra of the hindered rotational and translational excitations on the adsorbed H2 contain a significant amount of information, much of this can only be reliably extracted by means of a detailed analysis of the spectra through the utilization of models and theoretical calculations. For instance, the rotational tunneling transitions observed in the INS spectra can be related to a value for the barrier to rotation for the adsorbed H2 with the use of a simple phenomenological model. Since such an analysis is dependent on the model, it is far more desirable to use theoretical methods to compute a potential energy surface (PES), from which the rotational barriers for H2 adsorbed at a particular site can be determined. Rotational energy levels and transitions for the hindered rotor can be obtained by quantum dynamics calculations and compared directly with experiment with an accuracy subject only to the quality of the theoretical PES. In this paper, we review some of the quantum and classical mechanical calculations that have been performed on H2 adsorbed in various porous materials, such as clathrate hydrates, zeolites, and metal-organic frameworks (MOFs). The principal aims of these calculations have been the interpretation of the INS spectra for adsorbed H2 along with the extraction of atomic level details of its interaction with the host. We describe calculations of the PES used for two-dimensional quantum rotation as well as rigorous five-dimensional quantum coupled translation-rotation dynamics, and demonstrate that the combination of INS measurements and computational modeling can provide important and detailed insights into the molecular mechanism of H2 adsorption in porous materials. PMID:27160665

  17. Dynamics of H2 adsorbed in porous materials as revealed by computational analysis of inelastic neutron scattering spectra.

    PubMed

    Pham, Tony; Forrest, Katherine A; Space, Brian; Eckert, Juergen

    2016-06-29

    The inelastic scattering of neutrons from adsorbed H2 is an effective and highly sensitive method for obtaining molecular level information on the type and nature of H2 binding sites in porous materials. While these inelastic neutron scattering (INS) spectra of the hindered rotational and translational excitations on the adsorbed H2 contain a significant amount of information, much of this can only be reliably extracted by means of a detailed analysis of the spectra through the utilization of models and theoretical calculations. For instance, the rotational tunneling transitions observed in the INS spectra can be related to a value for the barrier to rotation for the adsorbed H2 with the use of a simple phenomenological model. Since such an analysis is dependent on the model, it is far more desirable to use theoretical methods to compute a potential energy surface (PES), from which the rotational barriers for H2 adsorbed at a particular site can be determined. Rotational energy levels and transitions for the hindered rotor can be obtained by quantum dynamics calculations and compared directly with experiment with an accuracy subject only to the quality of the theoretical PES. In this paper, we review some of the quantum and classical mechanical calculations that have been performed on H2 adsorbed in various porous materials, such as clathrate hydrates, zeolites, and metal-organic frameworks (MOFs). The principal aims of these calculations have been the interpretation of the INS spectra for adsorbed H2 along with the extraction of atomic level details of its interaction with the host. We describe calculations of the PES used for two-dimensional quantum rotation as well as rigorous five-dimensional quantum coupled translation-rotation dynamics, and demonstrate that the combination of INS measurements and computational modeling can provide important and detailed insights into the molecular mechanism of H2 adsorption in porous materials.

  18. Viscoelastic properties of adsorbed and cross-linked polypeptide and protein layers at a solid-liquid interface.

    PubMed

    Dutta, Amit K; Nayak, Arpan; Belfort, Georges

    2008-08-01

    The real-time changes in viscoelasticity of adsorbed poly(L-lysine) (PLL) and adsorbed histone (lysine rich fraction) due to cross-linking by glutaraldehyde and corresponding release of associated water were investigated using a quartz crystal microbalance with dissipation monitoring (QCM-D) and attenuated total reflection Fourier transform infrared spectroscopy (ATR/FTIR). The kinetics of PLL and histone adsorption were measured through changes in mass adsorbed onto a gold-coated quartz surface from changes in frequency and dissipation and using the Voigt viscoelastic model. Prior to cross-linking, the shear viscosity and shear modulus of the adsorbed PLL layer were approximately 3.0 x 10(-3) Pas and approximately 2.5 x 10(5) Pa, respectively, while after cross-linking, they increased to approximately 17.5 x 10(-3) Pas and approximately 2.5 x 10(6) Pa, respectively. For the adsorbed histone layer, shear viscosity and shear modulus increased modestly from approximately 1.3 x 10(-3) to approximately 2.0 x 10(-3) Pas and from approximately 1.2 x 10(4) to approximately 1.6 x 10(4) Pa, respectively. The adsorbed mass estimated from the Sauerbrey equation (perfectly elastic) and the Voigt viscoelastic model differ appreciably prior to cross-linking whereas after cross-linking they converged. This is because trapped water molecules were released during cross-linking. This was confirmed experimentally via ATR/FTIR measurements. The variation in viscoelastic properties increased substantially after cross-linking presumably due to fluctuation of the randomly cross-linked network structure. An increase in fluctuation of the viscoelastic properties and the loss of imbibed water could be used as a signature of the formation of a cross-linked network and the amount of cross-linking, respectively. PMID:18508070

  19. Breakthrough in Xenon Capture and Purification Using Adsorbent-Supported Silver Nanoparticles.

    PubMed

    Deliere, Ludovic; Coasne, Benoit; Topin, Sylvain; Gréau, Claire; Moulin, Christophe; Farrusseng, David

    2016-07-01

    Rare gas capture and purification is a major challenge for energy, environment, and health applications. Of utmost importance for the nuclear industry, novel separation processes for Xe are urgently needed for spent nuclear fuel reprocessing and nuclear activity monitoring. The recovered, non-radioactive Xe is also of high economic value for lighting, surgical anesthetic, etc. Here, using adsorption and breakthrough experiments and statistical mechanics molecular simulation, we show the outstanding performance of zeolite-supported silver nanoparticles to capture/separate Xe at low concentrations (0.087-100 ppm). We also establish the efficiency of temperature swing adsorption based on such adsorbents for Xe separation from Kr/Xe mixtures and air streams corresponding to off-gases generated by nuclear reprocessing. This study paves the way for the development of novel, cost-efficient technologies relying on the large selectivity/capacity of adsorbent-supported silver nanoparticles which surpass all materials ever tested. PMID:27249317

  20. Preparation of Graphene Oxide-Based Hydrogels as Efficient Dye Adsorbents for Wastewater Treatment

    NASA Astrophysics Data System (ADS)

    Guo, Haiying; Jiao, Tifeng; Zhang, Qingrui; Guo, Wenfeng; Peng, Qiuming; Yan, Xuehai

    2015-06-01

    Graphene oxide (GO) sheets exhibit superior adsorption capacity for removing organic dye pollutants from an aqueous environment. In this paper, the facile preparation of GO/polyethylenimine (PEI) hydrogels as efficient dye adsorbents has been reported. The GO/PEI hydrogels were achieved through both hydrogen bonding and electrostatic interactions between amine-rich PEI and GO sheets. For both methylene blue (MB) and rhodamine B (RhB), the as-prepared hydrogels exhibit removal rates within about 4 h in accordance with the pseudo-second-order model. The dye adsorption capacity of the hydrogel is mainly attributed to the GO sheets, whereas the PEI was incorporated to facilitate the gelation process of GO sheets. More importantly, the dye-adsorbed hydrogels can be conveniently separated from an aqueous environment, suggesting potential large-scale applications of the GO-based hydrogels for organic dye removal and wastewater treatment.

  1. On the interplay between chemical reactions and phase transitions for molecules adsorbed on solid surfaces

    NASA Astrophysics Data System (ADS)

    Stiles, M.; Metiu, H.

    1986-02-01

    There is a large body of experimental evidence suggesting that the rate of product formation in a reaction between adsorbed molecules is deeply modified when one of the reagents undergoes a phase transition or, more broadly speaking, an aggregation of some kind. Specific examples are: H2 and CO oxidation; methanol transformation into a methoxy radical on O/Cu; the water reaction with oxygen to form 2OH; the decomposition of N2O on Pt(111) which is affected by a phase transition in the outermost Pt layer; and the oxidation of Ni7. It is suspected that similar effects might operate on supported metal catalysts. We use Monte Carlo simulations to examine the manner in which reagent aggregation affects the reaction rate between molecules adsorbed on a solid surface. We discuss the temperature and concentration dependence of the rate of product formation.

  2. Viral clearance by flow-through mode ion exchange columns and membrane adsorbers.

    PubMed

    Miesegaes, G R; Lute, S C; Read, E K; Brorson, K A

    2014-01-01

    Anion exchange (AEX) is a common downstream purification operation for biotechnology products manufactured in cell culture such as therapeutic monoclonal antibodies (mAbs) and Fc-fusion proteins. We present a head-to-head comparison of the viral clearance efficiency of AEX adsorbers and column chromatography using the same process fluids and comparable run conditions. We also present overall trends from the CDER viral clearance database. In our comparison of multiple brands of resins and adsorbers, clearance of three model viruses (PPV, X-MuLV, and PR772) was largely comparable, with some exceptions which may reflect run conditions that had not been optimized on a resin/membrane specific basis.

  3. Radiation grafted adsorbents for newly emerging environmental applications

    NASA Astrophysics Data System (ADS)

    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.

  4. Trace contaminant studies of HSC adsorbent. M.S. Thesis

    NASA Technical Reports Server (NTRS)

    Yieh, D. T. N.

    1978-01-01

    The adsorption and desorption of fifteen trace contaminants on HSC (polyethylenimine coated acrylic ester) adsorbent were experimentally investigated with the following two objectives: to test the removal potential and the adsorption reversibility of the selected trace contaminants, and to test the effect a preadsorbed trace contaminant has on the CO2 adsorption capacity. The experimental method for acquiring the adsorption equilibrium data used is based on the volumetric (or displacement) concept of vacuum adsorption. From the experimental results, it was found that the HSC adsorbent has good adsorption potential for contaminants of alcohol compounds, esters, and benzene compounds; whereas, adsorption of ketone compounds, oxidizing and reducing agents are detrimental to the adsorbent. In addition, all liquid contaminants reduce the CO2 capacity of HSC adsorbent.

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

    NASA Astrophysics Data System (ADS)

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

    2015-03-01

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

  6. Mycotoxin detoxication of animal feed by different adsorbents.

    PubMed

    Huwig, A; Freimund, S; Käppeli, O; Dutler, H

    2001-06-20

    The contamination of animal feed with mycotoxins represents a worldwide problem for farmers. These toxins originate from molds whose growth on living and stored plants is almost unavoidable particularly under moist conditions. Mycotoxin-containing feed can cause serious diseases in farm animals resulting in suffering and even death and thus can cause substantial economic losses. The most applied method for protecting animals against mycotoxicosis is the utilization of adsorbents mixed with the feed which are supposed to bind the mycotoxins efficiently in the gastro-intestinal tract. Aluminosilicates are the preferred adsorbents, followed by activated charcoal and special polymers. The efficiency of mycotoxin binders, however, differs considerably depending mainly on the chemical structure of both the adsorbent and the toxin. This review describes the most important types of adsorbents and the respective mechanisms of adsorption. Data of the in vitro and in vivo efficacy of detoxication are given.

  7. New insights into perfluorinated adsorbents for analytical and bioanalytical applications.

    PubMed

    Marchetti, Nicola; Guzzinati, Roberta; Catani, Martina; Massi, Alessandro; Pasti, Luisa; Cavazzini, Alberto

    2015-01-01

    Perfluorinated (F-) adsorbents are generally prepared by bonding perfluoro-functionalized silanes to silica gels. They have been employed for a long time essentially as media for solid-phase extraction of F-molecules or F-tagged molecules in organic chemistry and heterogeneous catalysis. More recently, this approach has been extended to proteomics and metabolomics. Owing to their unique physicochemical properties, namely fluorophilicity and proteinophilicity, and a better understanding of some fundamental aspects of their behavior, new applications of F-adsorbents in the field of environmental science and bio-affinity studies can be envisaged. In this article, we revisit the most important features of F-adsorbents by focusing, in particular, on some basic information that has been recently obtained through (nonlinear) chromatographic studies. Finally, we try to envisage new applications and possibilities that F-adsorbents will allow in the near future. PMID:25358910

  8. Residence time determination for adsorbent beds of different configurations

    SciTech Connect

    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.

  9. Synthesis and optimization of a new starch-based adsorbent for dehumidification of air in a pressure-swing dryer

    SciTech Connect

    Anderson, L.E.; Gulati, M.; Westgate, P.J.; Kvam, E.P.; Bowman, K.; Ladisch, M.R.

    1996-04-01

    Corn grits selectivity adsorb water from many types of organic vapors and are used commercially to dry 2.8 billion L of fuel-grade fermentation ethanol annually. Evaluation of grits in a pressure-swing dryer at 308 kPa, combined with analyses of their physical properties, showed that the specific surface of the grits (0.5 m{sup 2}/g) limited steady-state drying of air to a dewpoint of {minus}20 C. By selectivity taking advantage of the best features of the natural material, a new class of natural adsorbents with a higher affinity for water was then synthesized using materials derived from corn: starch and cob flour. The chemical composition of the synthesized adsorbent was determined, as well as specific physical properties. Scanning electron microscopy showed the synthesized adsorbent surface had a large number of macropores (10--25 {mu}m in diameter) unlike corn grits which have limited porosity. This material gave reasonable and reproducible results similar to those obtained with molecular sieves using a commercially available pressure-swing air dryer. After 70 h of operation at 30 psi, the new adsorbent provided air at a dewpoint of {minus}63 C. The methods for preparing this material and an explanation of its performance in terms of macroscopic and microscopic structural characteristics are described.

  10. Efforts to Consolidate Chalcogels with Adsorbed Iodine

    SciTech Connect

    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

  11. Control of acid gases using a fluidized bed adsorber.

    PubMed

    Chiang, Bo-Chin; Wey, Ming-Yen; Yeh, Chia-Lin

    2003-08-01

    During incineration, secondary pollutants such as acid gases, organic compounds, heavy metals and particulates are generated. Among these pollutants, the acid gases, including sulfur oxides (SO(x)) and hydrogen chloride (HCl), can cause corrosion of the incinerator piping and can generate acid rain after being emitted to the atmosphere. To address this problem, the present study used a novel combination of air pollution control devices (APCDs), composed of a fluidized bed adsorber integrated with a fabric filter. The major objective of the work is to demonstrate the performance of a fluidized bed adsorber for removal of acid gases from flue gas of an incinerator. The adsorbents added in the fluidized bed adsorber were mainly granular activated carbon (AC; with or without chemical treatment) and with calcium oxide used as an additive. The advantages of a fluidized bed reactor for high mass transfer and high gas-solid contact can enhance the removal of acid gases when using a dry method. On the other hand, because the fluidized bed can filter particles, fine particles prior to and after passing through the fluidized bed adsorber were investigated. The competing adsorption on activated carbon between different characteristics of pollutants was also given preliminary discussion. The results indicate that the removal efficiencies of the investigated acid gases, SO(2) and HCl, are higher than 94 and 87%, respectively. Thus, a fluidized bed adsorber integrated with a fabric filter has the potential to replace conventional APCDs, even when there are other pollutants at the same time.

  12. Synthesis and CO₂ adsorption properties of molecularly imprinted adsorbents.

    PubMed

    Zhao, Yi; Shen, Yanmei; Bai, Lu; Hao, Rongjie; Dong, Liyan

    2012-02-01

    A series of molecularly imprinted adsorbents of CO(2) were developed by molecular self-assembly procedures, using ethanedioic acid, acrylamide, and ethylene glycol dimethacrylate as template, functional monomer, and cross-linker, respectively. Textural properties of these adsorbents were characterized by N(2) adsorption experiment, thermo-gravimetric analysis, and Fourier transform infrared spectroscopy. CO(2) adsorption capacities of adsorbents were investigated by thermo-gravimetric balance under 15% CO(2)/85% Ar atmosphere. Adsorption selectivity of CO(2) was studied by fixed-bed adsorption/desorption experiments. All the adsorbents displayed good thermal stability at 200 °C. Among them, MIP1b, with the higher amine content, exhibited the largest CO(2) capacity, which maintained steady after 50 adsorption-desorption cycles. Although MIP3 showed the highest specific surface, the CO(2) capacity was lower than that of MIP1b. CO(2) adsorption mechanism of molecularly imprinted adsorbents was determined to be physical sorption according to the adsorption enthalpies integrated from the DSC heatflow profiles. The calculated separation factors of CO(2) under 15% CO(2)/85% N(2) atmosphere were above 100 for all adsorbents.

  13. The leucine rich amelogenin protein (LRAP) adsorbs as monomers or dimers onto surfaces

    SciTech Connect

    Tarasevich, Barbara J.; Lea, Alan S.; Shaw, Wendy J.

    2010-03-15

    Amelogenin and amelogenin splice variants are believed to be involved in controlling the formation of the highly anisotropic and ordered hydroxyapatite crystallites that form enamel. The adsorption behavior of amelogenin proteins onto substrates is very important because protein-surface interactions are critical to it’s function. We have studied the adsorption of LRAP, a splice variant of amelogenin which may also contribute to enamel function, onto model self-assembled monolayers on gold containing of COOH, CH3, and NH2 end groups. Dynamic light scattering (DLS) experiments indicated that LRAP in phosphate buffered saline (PBS) and solutions at saturation with calcium phosphate contained aggregates of nanospheres. Null ellipsometry and atomic force microscopy (AFM) were used to study protein adsorption amounts and structures. Relatively high amounts of adsorption occurred onto the CH3 and NH2 surfaces from both calcium phosphate and PBS solutions. Adsorption was also promoted onto COOH surfaces when calcium was present in the solutions suggesting an interaction that involves calcium bridging with the negatively charged C-terminus. The ellipsometry and AFM studies suggested that the protein adsorbed onto all surfaces as LRAP monomers. We propose that the monomers adsorb onto the surfaces by disassembling or “shedding” from the nanospheres that are present in solution. This work reveals the importance of small subnanosphere-sized structures of LRAP at interfaces, structures that may be important in the biomineralization of tooth enamel.

  14. Removal of formaldehyde by adsorption and plasma treatment of mineral adsorbent

    NASA Astrophysics Data System (ADS)

    Saulich, K.; Müller, S.

    2013-01-01

    Formaldehyde is a harmful ambient air pollutant which can be produced by incomplete combustion processes, e.g. in power plants or automobiles. In this work a cycled adsorption and discharge process using mineral granulate in a packed bed dielectric barrier discharge plasma reactor was applied for formaldehyde (99 ppm) removal from gas streams. The mineral granulate used consisted of 80% halloysite and showed a good adsorption capacity for formaldehyde. In the discharge step, the adsorbed formaldehyde molecules were decomposed to COx and hydrocarbons in a N2 plasma at a low input discharge power of 2.2 W. The decomposition performance on adsorbed formaldehyde molecules was studied depending on space-time, a specific oxygen fraction of the carrier gas and the influence of temperature. With rising N2 space times in the discharge area, the total amount of decomposed formaldehyde molecules increased and the decomposition reaction mechanism shifted to CO2 formation. An oxygen fraction in the carrier gas further raised the oxidized amount of formaldehyde to CO2. The mineral granulate showed satisfied regeneration ability during the cycled plasma process.

  15. Gold recovery from low concentrations using nanoporous silica adsorbent

    NASA Astrophysics Data System (ADS)

    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

  16. Utility of adsorbents in the purification of drinking water: a review of characterization, efficiency and safety evaluation of various adsorbents.

    PubMed

    Dubey, Shashi Prabha; Gopal, Krishna; Bersillon, J L

    2009-05-01

    Clean drinking water is one of the implicit requisites fora healthy human population. However the growing industrialization and extensive use of chemicals for various concerns, has increased the burden of unwanted pollutants in the drinking water of developing countries like India. The entry of potentially hazardous substances into the biota has been magnifying day by day. In the absence of a possible stoppage of these, otherwise, useful chemicals, the only way to maintain safer water bodies is to develop efficient purifying technologies. One such immensely beneficial procedure that has been in use is that of purification of water using 'adsorbents'. Indigenous minerals and natural plants products have potential for removing many pollutants viz. fluoride, arsenic, nitrate, heavy metals, pesticides as well as trihalomethanes. Adsorbents which are derived from carbon, alumina, zeolite, clay minerals, iron ores, industrial by products, and natural products viz. parts of the plants, herbs and algal biomass offer promising potential of removal. In the recent years attention has been paid to develop process involving screening/pretreatment/activation/impregnation using alkalies, acids, alum, lime, manganese dioxide, ferric chloride and other chemicals which are found to enhance their adsorbing efficiency. Chemical characterization of these adsorbents recapitulates the mechanism of the process. It is imperative to observe that capacities of the adsorbents may vary depending on the characteristics, chemical modifications and concentration of the individual adsorbent. Removal kinetics is found to be based on the experimental conditions viz. pH, concentration of the adsorbate, quantity of the adsorbent and temperature. It is suggested that isotherm model is suitable tool to assess the adsorption capacities in batch and column modes. Safety evaluation and risk assessment of the process/products may be useful to provide guidelines for its sustainable disposal.

  17. Multiscale simulations of protein G B1 adsorbed on charged self-assembled monolayers.

    PubMed

    Liu, Jie; Liao, Chenyi; Zhou, Jian

    2013-09-10

    The orientation of an antibody plays an important role in the development of immunosensors. Protein G is an antibody binding protein, which specifically targets the Fc fragment of an antibody. In this work, the orientation of prototypical and mutated protein G B1 adsorbed on positively and negatively charged self-assembled monolayers was studied by parallel tempering Monte Carlo and all-atom molecular dynamics simulations. Both methods present generally similar orientation distributions of protein G B1 for each kind of surface. The root-mean-square deviation, DSSP, gyration radius, eccentricity, dipole moment, and superimposed structures of protein G B1 were analyzed. Moreover, the orientation of binding antibody was also predicted in this work. Simulation results show that with the same orientation trends, the mutant exhibits narrower orientation distributions than does the prototype, which was mainly caused by the stronger dipole of the mutant. Both kinds of proteins adsorbed on charged surfaces were induced by the competition of electrostatic interaction and vdW interaction; the electrostatic interaction energy dominated the adsorption behavior. The protein adsorption was also largely affected by the distribution of charged residues within the proteins. Thus, the prototype could adsorb on a negatively charged surface, although it keeps a net charge of -4 e. The mutant has imperfect opposite orientation when it adsorbed on oppositely charged surfaces. For the mutant on a carboxyl-functionalized self-assembled monolayer (COOH-SAM), the orientation was the same as that inferred by experiments. While for the mutant on amine-functionalized self-assembled monolayer (NH2-SAM), the orientation was induced by the competition between attractive interactions (led by ASP40 and GLU56) and repulsive interactions (led by LYS10); thus, the perfect opposite orientation could not be obtained. On both surfaces, the adsorbed protein could retain its native conformation. The desired

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

    PubMed

    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

  19. Expanded graphite loaded with lanthanum oxide used as a novel adsorbent for phosphate removal from water: performance and mechanism study.

    PubMed

    Zhang, Ling; Gao, Yan; Li, Mengxue; Liu, Jianyong

    2015-01-01

    A novel adsorbent of expanded graphite (EG) loaded with lanthanum oxide (EG-LaO) was prepared for phosphate removal from water and characterized by scanning electron microscopy (SEM) and Fourier transform infrared (FT-IR) spectroscopy. The effects of impregnation time, La3+ concentration, activation time, and activation temperature on the phosphate removal performance of the adsorbent were studied for optimization of preparation conditions. Isothermal adsorption studies suggested that the Langmuir model fits the experimental data well. Adsorption kinetics investigation showed that the pseudo-second-order model fits the experimental data quite well, indicating that the adsorption process is mainly a process of chemical adsorption, and chloride ions compete to react with the active sites of the adsorbent but do not prevent phosphate from adsorbing onto EG-LaO. The adsorption mechanism studies were performed by a pH dependence study of the adsorption amount. The results demonstrated that the probable mechanisms of phosphate adsorption on EG-LaO were electrostatic and Lewis acid-base interactions in addition to ion exchange.

  20. Diffusion in confinement: kinetic simulations of self- and collective diffusion behavior of adsorbed gases

    SciTech Connect

    Abouelnasr, MKF; Smit, B

    2012-01-01

    The self- and collective-diffusion behaviors of adsorbed methane, helium, and isobutane in zeolite frameworks LTA, MFI, AFI, and SAS were examined at various concentrations using a range of molecular simulation techniques including Molecular Dynamics (MD), Monte Carlo (MC), Bennett-Chandler (BC), and kinetic Monte Carlo (kMC). This paper has three main results. (1) A novel model for the process of adsorbate movement between two large cages was created, allowing the formulation of a mixing rule for the re-crossing coefficient between two cages of unequal loading. The predictions from this mixing rule were found to agree quantitatively with explicit simulations. (2) A new approach to the dynamically corrected Transition State Theory method to analytically calculate self-diffusion properties was developed, explicitly accounting for nanoscale fluctuations in concentration. This approach was demonstrated to quantitatively agree with previous methods, but is uniquely suited to be adapted to a kMC simulation that can simulate the collective-diffusion behavior. (3) While at low and moderate loadings the self- and collective-diffusion behaviors in LTA are observed to coincide, at higher concentrations they diverge. A change in the adsorbate packing scheme was shown to cause this divergence, a trait which is replicated in a kMC simulation that explicitly models this behavior. These phenomena were further investigated for isobutane in zeolite MFI, where MD results showed a separation in self- and collective-diffusion behavior that was reproduced with kMC simulations.

  1. Covalent triazine-based framework: A promising adsorbent for removal of perfluoroalkyl acids from aqueous solution.

    PubMed

    Wang, Bingyu; Lee, Linda S; Wei, Chenhui; Fu, Heyun; Zheng, Shourong; Xu, Zhaoyi; Zhu, Dongqiang

    2016-09-01

    Perfluoroalkyl acids (PFAAs) are highly stable, persistent, and ubiquitous in the environment with significant concerns growing with regards to both human and ecosystem health. Due to the high stability to both biological and chemical attack, the only currently feasible approach for their removal from water is adsorbent technology. The main objective of this study was to assess a covalent triazine-based framework (CTF) adsorbent for removal from aqueous solutions of perfluoro C4, C6, and C8 carboxylates and sulfonates including the two C8s most commonly monitored, perfluorooctanoic acid (PFOA) and perfluorooctane sulfonate (PFOS). Adsorption affinity and capacity were quantified and compared to three commonly used sorbents: pulverized microporous activated carbon, single-walled carbon nanotubes, and Amberlite IRA-400 anion-exchange resin. CTF adsorbent exhibited pronouncedly higher adsorption affinity and capacity of PFAAs than other test sorbents. The remarkably strong adsorption to CTF can be attributed to the favored electrostatic interaction between the protonated triazine groups on the inner wall of the hydrophobic CTF pore and the negatively charged head groups of the PFAAs intercalated between the CTF layers. The homogeneous, nanosized pores (1.2 nm) of CTF hindered adsorption of a large-sized dissolved humic acid, thus minimizing the suppression of PFAA adsorption. Additionally, regeneration of CTF was easily accomplished by simply raising pH > 11, which inhibited the electrostatic adsorptive interaction of PFAAs. PMID:27389552

  2. Magnetic graphene-carbon nanotube iron nanocomposites as adsorbents and antibacterial agents for water purification.

    PubMed

    Sharma, Virender K; McDonald, Thomas J; Kim, Hyunook; Garg, Vijayendra K

    2015-11-01

    One of the biggest challenges of the 21st century is to provide clean and affordable water through protecting source and purifying polluted waters. This review presents advances made in the synthesis of carbon- and iron-based nanomaterials, graphene-carbon nanotubes-iron oxides, which can remove pollutants and inactivate virus and bacteria efficiently in water. The three-dimensional graphene and graphene oxide based nanostructures exhibit large surface area and sorption sites that provide higher adsorption capacity to remove pollutants than two-dimensional graphene-based adsorbents and other conventional adsorbents. Examples are presented to demonstrate removal of metals (e.g., Cu, Pb, Cr(VI), and As) and organics (e.g., dyes and oil) by grapheme-based nanostructures. Inactivation of Gram-positive and Gram-negative bacterial species (e.g., Escherichia coli and Staphylococcus aureus) is also shown. A mechanism involving the interaction of adsorbents and pollutants is briefly discussed. Magnetic graphene-based nanomaterials can easily be separated from the treated water using an external magnet; however, there are challenges in implementing the graphene-based nanotechnology in treating real water. PMID:26498500

  3. Adsorption and conformational modification of fibronectin and fibrinogen adsorbed on hydroxyapatite. A QCM-D study.

    PubMed

    Fernández-Montes Moraleda, Belén; San Román, Julio; Rodríguez-Lorenzo, Luís M

    2016-10-01

    Hydroxyapatite is a bioactive ceramic frequently used for bone engineering/replacement. One of the parameters that influence the biological response to implanted materials is the conformation of the first adsorbed protein layer. In this work, the adsorption and conformational changes of two fibroid serum proteins; fibronectin and fibrinogen adsorbed onto four different hydroxyapatite powders are studied with a Quartz Crystal Microbalance with Dissipation (QCM-D). Each of the calcined apatites adsorbs less protein than their corresponding synthesized samples. Adsorption on synthesized samples yields always an extended conformation whereas a reorganization of the layer is observed for the calcined samples. Fg acquires a "Side on" conformation in all the samples at the beginning of the experiment except for one of the synthesized samples where an "End-on" conformation is obtained during the whole experiment. The Extended conformation is the active conformation for Fn. This conformation is favored by apatites with large specific surface area (SSA) and on highly concentrated media. Apatite surface features should be considered in the selection or design of materials for bone regeneration, since it is possible to control the conformation mode of attachment of Fn and Fg by an appropriate selection of them. © 2016 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 104A: 2585-2594, 2016.

  4. Adsorption and conformational modification of fibronectin and fibrinogen adsorbed on hydroxyapatite. A QCM-D study.

    PubMed

    Fernández-Montes Moraleda, Belén; San Román, Julio; Rodríguez-Lorenzo, Luís M

    2016-10-01

    Hydroxyapatite is a bioactive ceramic frequently used for bone engineering/replacement. One of the parameters that influence the biological response to implanted materials is the conformation of the first adsorbed protein layer. In this work, the adsorption and conformational changes of two fibroid serum proteins; fibronectin and fibrinogen adsorbed onto four different hydroxyapatite powders are studied with a Quartz Crystal Microbalance with Dissipation (QCM-D). Each of the calcined apatites adsorbs less protein than their corresponding synthesized samples. Adsorption on synthesized samples yields always an extended conformation whereas a reorganization of the layer is observed for the calcined samples. Fg acquires a "Side on" conformation in all the samples at the beginning of the experiment except for one of the synthesized samples where an "End-on" conformation is obtained during the whole experiment. The Extended conformation is the active conformation for Fn. This conformation is favored by apatites with large specific surface area (SSA) and on highly concentrated media. Apatite surface features should be considered in the selection or design of materials for bone regeneration, since it is possible to control the conformation mode of attachment of Fn and Fg by an appropriate selection of them. © 2016 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 104A: 2585-2594, 2016. PMID:27254464

  5. Magnetic graphene-carbon nanotube iron nanocomposites as adsorbents and antibacterial agents for water purification.

    PubMed

    Sharma, Virender K; McDonald, Thomas J; Kim, Hyunook; Garg, Vijayendra K

    2015-11-01

    One of the biggest challenges of the 21st century is to provide clean and affordable water through protecting source and purifying polluted waters. This review presents advances made in the synthesis of carbon- and iron-based nanomaterials, graphene-carbon nanotubes-iron oxides, which can remove pollutants and inactivate virus and bacteria efficiently in water. The three-dimensional graphene and graphene oxide based nanostructures exhibit large surface area and sorption sites that provide higher adsorption capacity to remove pollutants than two-dimensional graphene-based adsorbents and other conventional adsorbents. Examples are presented to demonstrate removal of metals (e.g., Cu, Pb, Cr(VI), and As) and organics (e.g., dyes and oil) by grapheme-based nanostructures. Inactivation of Gram-positive and Gram-negative bacterial species (e.g., Escherichia coli and Staphylococcus aureus) is also shown. A mechanism involving the interaction of adsorbents and pollutants is briefly discussed. Magnetic graphene-based nanomaterials can easily be separated from the treated water using an external magnet; however, there are challenges in implementing the graphene-based nanotechnology in treating real water.

  6. Removal of arsenic from groundwater by granular titanium dioxide adsorbent.

    PubMed

    Bang, Sunbaek; Patel, Manish; Lippincott, Lee; Meng, Xiaoguang

    2005-07-01

    A novel granular titanium dioxide (TiO2) was evaluated for the removal of arsenic from groundwater. Laboratory experiments were carried out to investigate the adsorption capacity of the adsorbent and the effect of anions on arsenic removal. Batch experimental results showed that more arsenate [As(V)] was adsorbed on TiO2 than arsenite [As(III)] in US groundwater at pH 7.0. The adsorption capacities for As(V) and As(III) were 41.4 and 32.4 mgg(-1) TiO2, respectively. However, the adsorbent had a similar adsorption capacity for As(V) and As(III) (approximately 40 mgg(-1)) when simulated Bangladesh groundwater was used. Silica (20 mgl(-1)) and phosphate (5.8 mgl(-1)) had no obvious effect on the removal of As(V) and As(III) by TiO2 at neutral pH. Point-of-entry (POE) filters containing 3 l of the granular adsorbent were tested for the removal of arsenic from groundwater in central New Jersey, USA. Groundwater was continuously passed through the filters at an empty bed contact time (EBCT) of 3 min. Approximately 45,000 bed volumes of groundwater containing an average of 39 microgl(-1) of As(V) was treated by the POE filter before the effluent arsenic concentration increased to 10 microgl(-1). The total treated water volumes per weight of adsorbent were about 60,000 l per 1 kg of adsorbent. The field filtration results demonstrated that the granular TiO2 adsorbent was very effective for the removal of arsenic in groundwater. PMID:15924958

  7. 7 CFR 1421.304 - Payment amount.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 2012 Crop of Wheat, Barley, Oats, and Triticale § 1421.304 Payment amount. (a) The grazing payment rate... payment rate in effect for the predominant class of wheat in the county where the farm is located as of... three (3) similar farms. For triticale, the payment yield shall be the yield for wheat from three...

  8. 7 CFR 1421.304 - Payment amount.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 2012 Crop of Wheat, Barley, Oats, and Triticale § 1421.304 Payment amount. (a) The grazing payment rate... payment rate in effect for the predominant class of wheat in the county where the farm is located as of... three (3) similar farms. For triticale, the payment yield shall be the yield for wheat from three...

  9. 7 CFR 1421.304 - Payment amount.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 2012 Crop of Wheat, Barley, Oats, and Triticale § 1421.304 Payment amount. (a) The grazing payment rate... payment rate in effect for the predominant class of wheat in the county where the farm is located as of... three (3) similar farms. For triticale, the payment yield shall be the yield for wheat from three...

  10. 7 CFR 1421.304 - Payment amount.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 2012 Crop of Wheat, Barley, Oats, and Triticale § 1421.304 Payment amount. (a) The grazing payment rate... payment rate in effect for the predominant class of wheat in the county where the farm is located as of... three (3) similar farms. For triticale, the payment yield shall be the yield for wheat from three...

  11. 7 CFR 1421.304 - Payment amount.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 2012 Crop of Wheat, Barley, Oats, and Triticale § 1421.304 Payment amount. (a) The grazing payment rate... payment rate in effect for the predominant class of wheat in the county where the farm is located as of... three (3) similar farms. For triticale, the payment yield shall be the yield for wheat from three...

  12. 14 CFR 1300.13 - Guarantee amount.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 14 Aeronautics and Space 5 2010-01-01 2010-01-01 false Guarantee amount. 1300.13 Section 1300.13 Aeronautics and Space AIR TRANSPORTATION SYSTEM STABILIZATION OFFICE OF MANAGEMENT AND BUDGET AVIATION DISASTER RELIEF-AIR CARRIER GUARANTEE LOAN PROGRAM Minimum Requirements and Application Procedures §...

  13. 24 CFR 201.10 - Loan amounts.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... MORTGAGE AND LOAN INSURANCE PROGRAMS UNDER NATIONAL HOUSING ACT AND OTHER AUTHORITIES TITLE I PROPERTY... actual cost of the project plus any applicable fees and charges authorized at § 201.25(b), up to the... exceed the sum of the following itemized amounts, up to a maximum of $48,600: (i) 130 percent of the...

  14. 21 CFR 1309.11 - Fee amounts.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 9 2010-04-01 2010-04-01 false Fee amounts. 1309.11 Section 1309.11 Food and Drugs DRUG ENFORCEMENT ADMINISTRATION, DEPARTMENT OF JUSTICE REGISTRATION OF MANUFACTURERS, DISTRIBUTORS, IMPORTERS AND EXPORTERS OF LIST I CHEMICALS Fees for Registration and Reregistration § 1309.11 Fee...

  15. 21 CFR 1309.11 - Fee amounts.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 9 2011-04-01 2011-04-01 false Fee amounts. 1309.11 Section 1309.11 Food and Drugs DRUG ENFORCEMENT ADMINISTRATION, DEPARTMENT OF JUSTICE REGISTRATION OF MANUFACTURERS, DISTRIBUTORS, IMPORTERS AND EXPORTERS OF LIST I CHEMICALS Fees for Registration and Reregistration § 1309.11 Fee...

  16. 27 CFR 70.243 - Exempt amount.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 27 Alcohol, Tobacco Products and Firearms 2 2014-04-01 2014-04-01 false Exempt amount. 70.243 Section 70.243 Alcohol, Tobacco Products and Firearms ALCOHOL AND TOBACCO TAX AND TRADE BUREAU, DEPARTMENT... as wages, salary, or other income for each payroll period described in § 70.244 of this part...

  17. 27 CFR 70.243 - Exempt amount.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 27 Alcohol, Tobacco Products and Firearms 2 2013-04-01 2013-04-01 false Exempt amount. 70.243 Section 70.243 Alcohol, Tobacco Products and Firearms ALCOHOL AND TOBACCO TAX AND TRADE BUREAU, DEPARTMENT... as wages, salary, or other income for each payroll period described in § 70.244 of this part...

  18. 27 CFR 70.243 - Exempt amount.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 27 Alcohol, Tobacco Products and Firearms 2 2012-04-01 2011-04-01 true Exempt amount. 70.243 Section 70.243 Alcohol, Tobacco Products and Firearms ALCOHOL AND TOBACCO TAX AND TRADE BUREAU, DEPARTMENT... as wages, salary, or other income for each payroll period described in § 70.244 of this part...

  19. 33 CFR 133.7 - Requests: Amount.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... POLLUTION FINANCIAL RESPONSIBILITY AND COMPENSATION OIL SPILL LIABILITY TRUST FUND; STATE ACCESS § 133.7... amount anticipated for immediate removal action for a single oil pollution incident, but, in any event... quantity and composition of the oil, weather conditions and customary costs of similar services in...

  20. 33 CFR 133.7 - Requests: Amount.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... POLLUTION FINANCIAL RESPONSIBILITY AND COMPENSATION OIL SPILL LIABILITY TRUST FUND; STATE ACCESS § 133.7... amount anticipated for immediate removal action for a single oil pollution incident, but, in any event... quantity and composition of the oil, weather conditions and customary costs of similar services in...

  1. 33 CFR 133.7 - Requests: Amount.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... POLLUTION FINANCIAL RESPONSIBILITY AND COMPENSATION OIL SPILL LIABILITY TRUST FUND; STATE ACCESS § 133.7... amount anticipated for immediate removal action for a single oil pollution incident, but, in any event... quantity and composition of the oil, weather conditions and customary costs of similar services in...

  2. 33 CFR 133.7 - Requests: Amount.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... POLLUTION FINANCIAL RESPONSIBILITY AND COMPENSATION OIL SPILL LIABILITY TRUST FUND; STATE ACCESS § 133.7... amount anticipated for immediate removal action for a single oil pollution incident, but, in any event... quantity and composition of the oil, weather conditions and customary costs of similar services in...

  3. 33 CFR 133.7 - Requests: Amount.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... POLLUTION FINANCIAL RESPONSIBILITY AND COMPENSATION OIL SPILL LIABILITY TRUST FUND; STATE ACCESS § 133.7... amount anticipated for immediate removal action for a single oil pollution incident, but, in any event... quantity and composition of the oil, weather conditions and customary costs of similar services in...

  4. 40 CFR 35.9050 - Assistance amount.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 1 2010-07-01 2010-07-01 false Assistance amount. 35.9050 Section 35.9050 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY GRANTS AND OTHER FEDERAL ASSISTANCE STATE AND LOCAL ASSISTANCE Financial Assistance for the National Estuary Program § 35.9050...

  5. 40 CFR 35.9050 - Assistance amount.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 1 2011-07-01 2011-07-01 false Assistance amount. 35.9050 Section 35.9050 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY GRANTS AND OTHER FEDERAL ASSISTANCE STATE AND LOCAL ASSISTANCE Financial Assistance for the National Estuary Program § 35.9050...

  6. 40 CFR 35.9050 - Assistance amount.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 1 2013-07-01 2013-07-01 false Assistance amount. 35.9050 Section 35.9050 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY GRANTS AND OTHER FEDERAL ASSISTANCE STATE AND LOCAL ASSISTANCE Financial Assistance for the National Estuary Program § 35.9050...

  7. 40 CFR 35.9050 - Assistance amount.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 1 2014-07-01 2014-07-01 false Assistance amount. 35.9050 Section 35.9050 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY GRANTS AND OTHER FEDERAL ASSISTANCE STATE AND LOCAL ASSISTANCE Financial Assistance for the National Estuary Program § 35.9050...

  8. 40 CFR 35.9050 - Assistance amount.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 1 2012-07-01 2012-07-01 false Assistance amount. 35.9050 Section 35.9050 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY GRANTS AND OTHER FEDERAL ASSISTANCE STATE AND LOCAL ASSISTANCE Financial Assistance for the National Estuary Program § 35.9050...

  9. 20 CFR 340.2 - Amount recoverable.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... amount of unemployment, sickness, or maternity benefits paid under the Railroad Unemployment Insurance... been determined to be days of unemployment or sickness; (c) Recoverable under section 4(a-1)(ii) of the..., unemployment, sickness or maternity benefits under any law other than the Railroad Unemployment Insurance...

  10. 20 CFR 340.2 - Amount recoverable.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... amount of unemployment, sickness, or maternity benefits paid under the Railroad Unemployment Insurance... been determined to be days of unemployment or sickness; (c) Recoverable under section 4(a-1)(ii) of the..., unemployment, sickness or maternity benefits under any law other than the Railroad Unemployment Insurance...

  11. 20 CFR 340.2 - Amount recoverable.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... amount of unemployment, sickness, or maternity benefits paid under the Railroad Unemployment Insurance... been determined to be days of unemployment or sickness; (c) Recoverable under section 4(a-1)(ii) of the..., unemployment, sickness or maternity benefits under any law other than the Railroad Unemployment Insurance...

  12. Cyclic ethers adsorbed on Ru(001)

    NASA Astrophysics Data System (ADS)

    Walczak, M. M.; Thiel, P. A.

    1990-11-01

    The three cyclic ethers 1,3-dioxane. 1,4-dioxane and 1,3,5-trioxane all exhibit multiple desorption states from Ru(001) between 200 and 310 K, in addition to the multilayer and metastable states at lower temperature. Most distinctive are the two low-temperature α-states. which are similar in shape, position, and relative population for all three compounds. This suggests that these states are associated with configurations which are accessible to all three molecules. The data also indicate that there is some molecular decomposition to gaseous CO and H 2. 1,4-Dioxane yields the largest amounts of these decomposition products, suggesting that this molecule is most susceptible to surface-catalyzed decomposition. The desorption data for the three cyclic ethers are grossly similar to each other, and also to the straight-chain diethers which we have previously studied.

  13. In vitro and in vivo evaluation of ordered mesoporous silica as a novel adsorbent in liquisolid formulation

    PubMed Central

    Chen, Bao; Wang, Zhouhua; Quan, Guilan; Peng, Xinsheng; Pan, Xin; Wang, Rongchang; Xu, Yuehong; Li, Ge; Wu, Chuanbin

    2012-01-01

    Background A liquisolid technique has been reported to be a new approach to improve the release of poorly water-soluble drugs for oral administration. However, an apparent limitation of this technique is the formulation of a high dose because a large amount of liquid vehicle is needed, which finally results in a low-dose liquisolid formulation. Silica as an absorbent has been used extensively in liquisolid formulations. Although nanoparticle silica can be prepared and used to improve liquid adsorption capacity, loading a high dose of drug into a liquisolid is still a challenge. With the aim of improving adsorption capacity and accordingly achieving high drug loading, ordered mesoporous silica with a high surface area and narrow pore size distribution was synthesized and used in a liquisolid formulation. Methods Ordered mesoporous silica was synthesized and its particle size and morphology were tailored by controlling the concentration of cetyltrimethyl ammonium bromide. The ordered mesoporous silica synthesized was characterized by transmission electron microscopy, scanning electron microscopy, Fourier transform infrared spectroscopy, small-angle x-ray diffraction, wide angle x-ray diffraction, and nitrogen adsorption-desorption measurements. The liquid adsorption capacity of ordered mesoporous silica was subsequently compared with that of conventional silica materials using PEG400 as the model liquid. Carbamazepine was chosen as a model drug to prepare the liquisolid formulation, with ordered mesoporous silica as the adsorbent material. The preparation was evaluated and compared with commercially available fast-release carbamazepine tablets in vitro and in vivo. Results Characterization of the ordered mesoporous silica synthesized in this study indicated a huge Brunauer–Emmett–Teller surface area (1030 m2/g), an ordered mesoporous structure with a pore size of 2.8 nm, and high adsorption capacity for liquid compared with conventional silica. Compared with fast

  14. Sequence-defined Energetic Shifts Control the Disassembly Kinetics and Microstructure of Amelogenin Adsorbed onto Hydroxyapatite (100)

    SciTech Connect

    Tao, Jinhui; Buchko, Garry W.; Shaw, Wendy J.; De Yoreo, Jim; Tarasevich, Barbara J.

    2015-11-03

    The interactions between proteins and surfaces are critical to a number of important processes including biomineralization, the biocompatibility of biomaterials, and the function of biosensors. Although many proteins exist as monomers or small oligomers, amelogenin is a unique protein that self-assembles into supramolecular structures called “nanospheres,” aggregates of 100’s of monomers that are 20-60 nm in diameter. The nanosphere quaternary structure is observed in solution, however, the quaternary structure of amelogenin adsorbed onto hydroxyapatite (HAP) surfaces is not known even though it may be important to amelogenin’s function in forming highly elongated and intricately assembled HAP crystallites during enamel formation. We report studies of the interactions of the enamel protein, amelogenin (rpM179), with a well-defined (100) face prepared by synthesis of large crystals of HAP. High resolution, in-situ atomic force microscopy (AFM) was used to directly observe protein adsorption onto HAP at the molecular level within an aqueous solution environment. Our study shows that the amelogenin nanospheres disassemble onto the HAP surface, breaking down into oligomeric (25-mer) subunits of the larger nanosphere. In some cases, the disassembly event is directly observed by in situ imaging for the first time. Quantification of the adsorbate amounts by size analysis led to the determination of a protein binding energy (17.1 kbT) to a specific face of HAP (100). The kinetics of disassembly are greatly slowed in aged solutions, indicating there are time-dependent increases in oligomer-oligomer binding interactions within the nanosphere. A small change in the sequence of amelogenin by the attachment of a histidine tag to the N-terminus of rpM179 to form rp(H)M180 results in the adsorption of a complete second layer on top of the underlying first layer. Our research elucidates how supramolecular protein structures interact and break down at surfaces and how small

  15. Removal of phosphate from water by a Fe-Mn binary oxide adsorbent.

    PubMed

    Zhang, Gaosheng; Liu, Huijuan; Liu, Ruiping; Qu, Jiuhui

    2009-07-15

    Phosphate removal is important in the control of eutrophication of water bodies and adsorption is one of the promising approaches for this purpose. A Fe-Mn binary oxide adsorbent with a Fe/Mn molar ratio of 6:1 for phosphate removal was synthesized by a simultaneous oxidation and coprecipitation process. Laboratory experiments were carried out to investigate adsorption kinetics and equilibrium, in batch mode. The effects of different experimental parameters, namely contact time, initial phosphate concentration, solution pH, and ionic strength on the phosphate adsorption were investigated. The adsorption data were analyzed by both Freundlich and Langmuir isotherm models and the data were well fit by the Freundlich isotherm model. Kinetic data correlated well with the pseudo-second-order kinetic model, suggesting that the adsorption process might be chemical sorption. The maximal adsorption capacity was 36 mg/g at pH 5.6. The phosphate adsorption was highly pH dependent. The effects of anions such as Cl(-),SO42-, and CO32- on phosphate removal were also investigated. The results suggest that the presence of these ions had no significant effect on phosphate removal. The phosphate removal was mainly achieved by the replacement of surface hydroxyl groups by the phosphate species and formation of inner-sphere surface complexes at the water/oxide interface. In addition, the adsorbed phosphate ions can be effectively desorbed by dilute NaOH solutions. This adsorbent, with large adsorption capacity and high selectivity, is therefore a very promising adsorbent for the removal of phosphate ions from aqueous solutions.

  16. Adlayer structure dependent ultrafast desorption dynamics in carbon monoxide adsorbed on Pd (111).

    PubMed

    Hong, Sung-Young; Xu, Pan; Camillone, Nina R; White, Michael G; Camillone, Nicholas

    2016-07-01

    We report our ultrafast photoinduced desorption investigation of the coverage dependence of substrate-adsorbate energy transfer in carbon monoxide adlayers on the (111) surface of palladium. As the CO coverage is increased, the adsorption site population shifts from all threefold hollows (up to 0.33 ML), to bridge and near bridge (>0.5 to 0.6 ML) and finally to mixed threefold hollow plus top site (at saturation at 0.75 ML). We show that between 0.24 and 0.75 ML this progression of binding site motifs is accompanied by two remarkable features in the ultrafast photoinduced desorption of the adsorbates: (i) the desorption probability increases roughly two orders magnitude, and (ii) the adsorbate-substrate energy transfer rate observed in two-pulse correlation experiments varies nonmonotonically, having a minimum at intermediate coverages. Simulations using a phenomenological model to describe the adsorbate-substrate energy transfer in terms of frictional coupling indicate that these features are consistent with an adsorption-site dependent electron-mediated energy coupling strength, ηel, that decreases with binding site in the order: three-fold hollow > bridge and near bridge > top site. This weakening of ηel largely counterbalances the decrease in the desorption activation energy that accompanies this progression of adsorption site motifs, moderating what would otherwise be a rise of several orders of magnitude in the desorption probability. Within this framework, the observed energy transfer rate enhancement at saturation coverage is due to interadsorbate energy transfer from the copopulation of molecules bound in three-fold hollows to their top-site neighbors.

  17. Adlayer structure dependent ultrafast desorption dynamics in carbon monoxide adsorbed on Pd (111)

    NASA Astrophysics Data System (ADS)

    Hong, Sung-Young; Xu, Pan; Camillone, Nina R.; White, Michael G.; Camillone, Nicholas

    2016-07-01

    We report our ultrafast photoinduced desorption investigation of the coverage dependence of substrate-adsorbate energy transfer in carbon monoxide adlayers on the (111) surface of palladium. As the CO coverage is increased, the adsorption site population shifts from all threefold hollows (up to 0.33 ML), to bridge and near bridge (>0.5 to 0.6 ML) and finally to mixed threefold hollow plus top site (at saturation at 0.75 ML). We show that between 0.24 and 0.75 ML this progression of binding site motifs is accompanied by two remarkable features in the ultrafast photoinduced desorption of the adsorbates: (i) the desorption probability increases roughly two orders magnitude, and (ii) the adsorbate-substrate energy transfer rate observed in two-pulse correlation experiments varies nonmonotonically, having a minimum at intermediate coverages. Simulations using a phenomenological model to describe the adsorbate-substrate energy transfer in terms of frictional coupling indicate that these features are consistent with an adsorption-site dependent electron-mediated energy coupling strength, ηel, that decreases with binding site in the order: three-fold hollow > bridge and near bridge > top site. This weakening of ηel largely counterbalances the decrease in the desorption activation energy that accompanies this progression of adsorption site motifs, moderating what would otherwise be a rise of several orders of magnitude in the desorption probability. Within this framework, the observed energy transfer rate enhancement at saturation coverage is due to interadsorbate energy transfer from the copopulation of molecules bound in three-fold hollows to their top-site neighbors.

  18. Structure and Reactivity of Adsorbed Fibronectin Films on Mica

    PubMed Central

    Hull, James R.; Tamura, Glen S.; Castner, David G.

    2007-01-01

    Understanding the interactions of adsorbed fibronectin (Fn) with other biomolecules is important for many biomedical applications. Fn is found in almost all body fluids, in the extracellular matrix, and plays a fundamental role in many biological processes. This study found that the structure (conformation, orientation) and reactivity of Fn adsorbed onto mica is dependent on the Fn surface concentration. Atomic force microscopy and x-ray photoelectron spectroscopy were used to determine the surface coverage of adsorbed Fn from isolated molecules at low surface coverage to full monolayers at high surface coverage. Both methods showed that the thickness of Fn film continued to increase after the mica surface was completely covered, consistent with Fn adsorbed in a more upright conformation at the highest surface-Fn concentrations. Time-of-flight secondary ion mass spectrometry showed that relative intensities of both sulfur-containing (cystine, methionine) and hydrophobic (glycine, leucine/isoleucine) amino acids varied with changing Fn surface coverage, indicating that the conformation of adsorbed Fn depended on surface coverage. Single-molecule force spectroscopy with collagen-related peptides immobilized onto the atomic force microscope tip showed that the specific interaction force between the peptide and Fn increases with increasing Fn surface coverage. PMID:17890402

  19. In vitro evaluation of the capacity of zeolite and bentonite to adsorb aflatoxin B1 in simulated gastrointestinal fluids.

    PubMed

    Thieu, N Q; Pettersson, H

    2008-09-01

    Anin vitro study using single concentration and isotherm adsorption was carried out to evaluate the capacity of Vietnamese produced zeolite and bentonite to adsorb aflatoxin B1 (AFB1) in simulated gastrointestinal fluids (SGFs), and a commercial sorbent hydrated sodium calcium aluminosilicate (HSCAS) was used as reference. In this study, AFB1 solution was mixed with sorbents (0.3, 0.4 and 0.5% w/v) in SGFs at pH 3 and pH 7 and shaken for 8 h, centrifuged and the supernatant measured by Vicam fluorometer. Adsorption of AFB1 onto zeolite and bentonite varied according to the pH of SGFs and was lower than HSCAS. Linearity between the increased amount of AFB1 adsorbed on sorbents and the decrease of sorbent concentration was observed for bentonite and HSCAS, except for zeolite in SGFs at pH 7. The observed maximum amounts of AFB1 adsorbed on bentonite and HSCAS were 1.54 and 1.56 mg/g, respectively. The adsorption capacities of bentonite and HSCAS for AFB1 were 12.7 and 13.1 mg/g, respectively, from fitting the data to the Freundlich isotherm equation. Improvement in processing and purification for bentonite is needed to enhance the surface area, which would probably result in better adsorptive capacity for this sorbent. PMID:23604746

  20. Performance of mango seed adsorbents in the adsorption of anthraquinone and azo acid dyes in single and binary aqueous solutions.

    PubMed

    Dávila-Jiménez, Martín M; Elizalde-González, María P; Hernández-Montoya, Virginia

    2009-12-01

    In this study the husk of mango seed and two carbonaceous adsorbents prepared from it were used to study the adsorption behavior of eight acid dyes. The adsorbed amount in mmol m(-2) decayed asymptotically as the molecular volume and area increased. The interaction between the studied dyes and the mesoporous carbon was governed by the ionic species in solution and the acidic/basic groups on the surface. Less than 50% of the external surface of the microporous carbon became covered with the dyes molecules, though monolayer formation demonstrating specific interactions only with active sites on the surface and the adsorption magnitudes correlated with the shape parameter of the molecule within a particular dye group. The adsorption behavior in mixtures was determined by the molecular volume of the constituents; the greater the molecular volume difference, the greater the effect on the adsorbed amount. We also demonstrated that the raw husk of the mango seed can be used to remove up to 50% from model 50 mg l(-1) solutions of the studied acid dyes.

  1. Amplification of trace amounts of nucleic acids

    DOEpatents

    Church, George M.; Zhang, Kun

    2008-06-17

    Methods of reducing background during amplification of small amounts of nucleic acids employ careful analysis of sources of low level contamination. Ultraviolet light can be used to reduce nucleic acid contaminants in reagents and equipment. "Primer-dimer" background can be reduced by judicious design of primers. We have shown clean signal-to-noise with as little as starting material as one single human cell (.about.6 picogram), E. coli cell (.about.5 femtogram) or Prochlorococcus cell (.about.3 femtogram).

  2. Theoretical framework for the interpretation of STM images of adsorbates.

    PubMed

    Kenkre, V M; Biscarini, F; Bustamante, C

    1992-07-01

    A theoretical formalism for the interpretation of STM images of adsorbates is developed by approaching the calculation of the observed current as a transport problem in quantum statistical mechanics. The STM configuration is treated as a system of three groups of states--the substrate, the adsorbate and the tip--in contact with a thermal reservoir, with which it exchanges energy. A new definition of current is introduced, and shown to be related to that given in the traditional transfer Hamiltonian approach. The transport instrument used for the description is the stochastic Liouville equation, known to have the advantage of allowing the incorporation of thermal effects as well as arbitrary degree of coherence in the quantum transport. Some preliminary calculations of STM images of simple adsorbate models are presented.

  3. Lotus Dust Mitigation Coating and Molecular Adsorber Coating

    NASA Technical Reports Server (NTRS)

    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.

  4. Method of recovering adsorbed liquid compounds from molecular sieve columns

    DOEpatents

    Burkholder, Harvey R.; Fanslow, Glenn E.

    1983-01-01

    Molecularly adsorbed volatile liquid compounds are recovered from molecular sieve adsorbent columns by directionally applying microwave energy to the bed of the adsorbent to produce a mixed liquid-gas effluent. The gas portion of the effluent generates pressure within the bed to promote the discharge of the effluent from the column bottoms. Preferably the discharged liquid-gas effluent is collected in two to three separate fractions, the second or intermediate fraction having a substantially higher concentration of the desorbed compound than the first or third fractions. The desorption does not need to be assisted by passing a carrier gas through the bed or by applying reduced pressure to the outlet from the bed.

  5. Adsorption of lead ions on composite biopolymer adsorbent

    SciTech Connect

    Seki, Hideshi; Suzuki, Akira

    1996-04-01

    A fundamental study about the application of biopolymers to the recovery of lead from dilute solution was carried out. A membranous composite biopolymer adsorbent containing two kind of biopolymers, alginic acid (AA) and humic acid (HA), was prepared. HA, which has high solubility in water, was almost completely immobilized in the adsorbent by a combination of calcium alginate gel and activated carbon powder. A general model for complexation between divalent metal ions and acidic sites on biopolymers was applied to explain the adsorption mechanism of lead on the adsorbent (HA-M). The results showed that the complexation constants and the complexation capacities of lead-AA and lead-HA systems were scarcely influenced by immobilization.

  6. Method of recovering adsorbed liquid compounds from molecular sieve columns

    DOEpatents

    Burkholder, H.R.; Fanslow, G.E.

    1983-12-20

    Molecularly adsorbed volatile liquid compounds are recovered from molecular sieve adsorbent columns by directionally applying microwave energy to the bed of the adsorbent to produce a mixed liquid-gas effluent. The gas portion of the effluent generates pressure within the bed to promote the discharge of the effluent from the column bottoms. Preferably the discharged liquid-gas effluent is collected in two to three separate fractions, the second or intermediate fraction having a substantially higher concentration of the desorbed compound than the first or third fractions. The desorption does not need to be assisted by passing a carrier gas through the bed or by applying reduced pressure to the outlet from the bed. 8 figs.

  7. Modified Mesoporous Silica (SBA–15) with Trithiane as a new effective adsorbent for mercury ions removal from aqueous environment

    PubMed Central

    2014-01-01

    Background Removal of mercury from aqueous environment has been highly regarded in recent years and different methods have been tested for this purpose. One of the most effective ways for mercury ions (Hg+2) removal is the use of modified nano porous compounds. Hence, in this work a new physical modification of mesoporous silica (SBA-15) with 1, 3, 5 (Trithiane) as modifier ligand and its application for the removal of Hg+2 from aqueous environment has been investigated. SBA-15 and Trithiane were synthesized and the presence of ligand in the silica framework was demonstrated by FTIR spectrum. The amounts of Hg+2 in the samples were determined by cold vapor generation high resolution continuum source atomic absorption spectroscopy. Also, the effects of pH, stirring time and weight of modified SBA-15 as three major parameters for effective adsorption of Hg+2 were studied. Results The important parameter for the modification of the adsorbent was Modification ratio between ligand and adsorbent in solution which was 1.5. The results showed that the best Hg+2 removal condition was achieved at pH = 5.0, stirring time 15 min and 15.0 mg of modified adsorbent. Moreover, the maximum percentage removal of Hg+2 and the capacity of adsorbent were 85% and 10.6 mg of Hg+2/g modified SBA-15, respectively. Conclusions To sum up, the present investigation introduced a new modified nano porous compound as an efficient adsorbent for removal of Hg+2 from aqueous environment. PMID:25097760

  8. Interaction of alkali atoms with water multilayers adsorbed on TiO 2(1 1 0): a study with MIES and UPS

    NASA Astrophysics Data System (ADS)

    Krischok, S.; Höfft, O.; Kempter, V.

    2003-06-01

    The chemistry of alkali atoms (Li, Na, K, Cs) embedded in a multilayer aqueous environment was studied with metastable impact electron spectroscopy (MIES) and ultraviolet photoemission spectroscopy (UPS) (HeI and II) under ultra high vacuum (UHV) conditions. The water multilayers were grown at 130 K on a rutile, 1×1 reconstructed, TiO 2(1 1 0) single crystal. The behavior of the multilayer system was investigated as a function of the temperature (130-500 K). Due to the relatively large escape depth of the emitted electrons UPS provides spectroscopic information about several layers in contrast to MIES which is only sensitive to the outermost layer. This allows us to discriminate between species adsorbed at the water multilayer and species, which are embedded in the solvent or at the substrate-solvent interface. Furthermore, MIES is, in contrast to UPS, very sensitive to the outermost s-states of adsorbed alkali atoms, which are considered to be responsible for the high reactivity of these metals. The present study gives insight into the complicated chemistry of alkali atoms added to an aqueous multilayer system. The chosen combination of MIES and UPS allows us to distinguish clearly between various phases depending on the amount of offered alkali atoms. For low alkali concentrations the alkali atoms penetrate the water surface whereby they dissociate some water. With increasing exposure more and more water molecules become dissociated, whereby the outermost water layer remains intact. Finally, the chemistry between water and alkali atoms takes place at the outermost surface too, which is manifested by the formation of OH-groups at the surface. With further increasing alkali concentration the atoms start to adsorb as neutral atoms; whereby the spectrum of the alkali species is then strongly influenced by the underlying solvent system. For very high exposure the observed spectra are not influenced by the underlying aqueous system anymore; the formation of an alkali

  9. Experimental characterization of adsorbed protein orientation, conformation, and bioactivity

    PubMed Central

    Thyparambil, Aby A.; Wei, Yang; Latour, Robert A.

    2015-01-01

    Protein adsorption on material surfaces is a common phenomenon that is of critical importance in many biotechnological applications. The structure and function of adsorbed proteins are tightly interrelated and play a key role in the communication and interaction of the adsorbed proteins with the surrounding environment. Because the bioactive state of a protein on a surface is a function of the orientation, conformation, and accessibility of its bioactive site(s), the isolated determination of just one or two of these factors will typically not be sufficient to understand the structure–function relationships of the adsorbed layer. Rather a combination of methods is needed to address each of these factors in a synergistic manner to provide a complementary dataset to characterize and understand the bioactive state of adsorbed protein. Over the past several years, the authors have focused on the development of such a set of complementary methods to address this need. These methods include adsorbed-state circular dichroism spectropolarimetry to determine adsorption-induced changes in protein secondary structure, amino-acid labeling/mass spectrometry to assess adsorbed protein orientation and tertiary structure by monitoring adsorption-induced changes in residue solvent accessibility, and bioactivity assays to assess adsorption-induced changes in protein bioactivity. In this paper, the authors describe the methods that they have developed and/or adapted for each of these assays. The authors then provide an example of their application to characterize how adsorption-induced changes in protein structure influence the enzymatic activity of hen egg-white lysozyme on fused silica glass, high density polyethylene, and poly(methyl-methacrylate) as a set of model systems. PMID:25708632

  10. A new adsorbent for boron removal from aqueous solutions.

    PubMed

    Kluczka, Joanna; Korolewicz, Teofil; Zołotajkin, Maria; Simka, Wojciech; Raczek, Malwina

    2013-01-01

    A new adsorbent based on natural clinoptilolite and amorphous zirconium dioxide (ZrO2) was prepared for the uptake of boron from fresh water. The sorption behaviour of this adsorbent for boron was investigated using a batch system and found to obey Langmuir, Freundlich and Dubinin-Radushkevich (D-R) isotherm models. The ZrO2 loading level, pH, temperature, contact time, initial boron concentration and adsorbent dose, on the removal of boron were studied. It was found that the removal of boron increased while the adsorbent dose increased and the temperature decreased at an optimum pH (pH = 8) and a contact time of 30 min. At optimum conditions, the maximum boron percentage removal was 75%. According to the D-R model, the maximum capacity was estimated to be > 3 mg B/g of the adsorbent. The adsorption energy value (calculated as 9.13 kJ/mol) indicated that the adsorption of boron on clinoptilolite modified with ZrO2 was physical in nature. The parameters of the adsorption models and the pH investigations pointed to the possibility of a chemisorption process. The thermodynamic parameters (standard entropy deltaS degrees, enthalpy deltaH degrees , and free energy deltaG degrees changes) of boron adsorption were also calculated. The negative value of deltaS degrees indicated a decreased randomness at the solid-solution interface during the boron adsorption. Negative values of deltaH degrees showed the exothermic nature of the process. The negative values of deltaG degrees implied that the adsorption of boron on clinoptilolite modified with amorphous ZrO2 at 25 degrees C was spontaneous. It was considered that boron dissolved in water had been adsorbed both physically and chemically on clinoptilolite modified with 30% ZrO2.

  11. Experimental characterization of adsorbed protein orientation, conformation, and bioactivity.

    PubMed

    Thyparambil, Aby A; Wei, Yang; Latour, Robert A

    2015-01-01

    Protein adsorption on material surfaces is a common phenomenon that is of critical importance in many biotechnological applications. The structure and function of adsorbed proteins are tightly interrelated and play a key role in the communication and interaction of the adsorbed proteins with the surrounding environment. Because the bioactive state of a protein on a surface is a function of the orientation, conformation, and accessibility of its bioactive site(s), the isolated determination of just one or two of these factors will typically not be sufficient to understand the structure-function relationships of the adsorbed layer. Rather a combination of methods is needed to address each of these factors in a synergistic manner to provide a complementary dataset to characterize and understand the bioactive state of adsorbed protein. Over the past several years, the authors have focused on the development of such a set of complementary methods to address this need. These methods include adsorbed-state circular dichroism spectropolarimetry to determine adsorption-induced changes in protein secondary structure, amino-acid labeling/mass spectrometry to assess adsorbed protein orientation and tertiary structure by monitoring adsorption-induced changes in residue solvent accessibility, and bioactivity assays to assess adsorption-induced changes in protein bioactivity. In this paper, the authors describe the methods that they have developed and/or adapted for each of these assays. The authors then provide an example of their application to characterize how adsorption-induced changes in protein structure influence the enzymatic activity of hen egg-white lysozyme on fused silica glass, high density polyethylene, and poly(methyl-methacrylate) as a set of model systems. PMID:25708632

  12. Adsorbent selection for endosulfan removal from water environment.

    PubMed

    Sudhakar, Y; Dikshit, A K

    1999-01-01

    In the present study, an attempt was made to select a low cost adsorbing material for the removal of endosulfan [C,C'-(1,4,5,6,7,7-hexachloro-8,9,10- trinorborn-5-en-2,3-ylene)(dimethylsulphite)] from water. Various low cost adsorbents like wood charcoal, kimberlite tailings, silica, macro fungi sojar caju were tried with activated charcoal as reference material. The above materials were selected from various sources encompassing organic, inorganic, clayey, and biological sources. For the selection of suitable adsorbent for endosulfan uptake, maximum adsorption capacity (Qmax) was chosen as the parameter. Kinetic profiles of removal were generated for all the materials to assess the equilibrium time. Equilibrium studies were carried out for all materials to assess the adsorption equilibrium model that they followed. The model that gave the best correlation coefficient by linear regression analysis, was adopted for the calculation of Qmax of the corresponding adsorbent material. Using linearised forms of equilibrium models like Langmuir, BET, and Freundlich, maximum adsorptive capacities were determined. Activated charcoal showed the best adsorptive capacity with Qmax of 2.145 mg/g followed by wood charcoal 1.773 mg/g, sojar caju 1.575 mg/g, kimberlite tailings 0.8821 mg/g, and silica 0.3231 mg/g. Albeit activated charcoal gave better performance, it was not considered as a candidate material because of its high cost. Wood charcoal was the next best adsorbent with Qmax 1.773 mg/g. Therefore, wood charcoal was chosen as the best material for endosulfan removal. The study of physical and chemical characteristics of wood charcoal revealed that it is a potential adsorbent and can even be improved further.

  13. A new adsorbent for boron removal from aqueous solutions.

    PubMed

    Kluczka, Joanna; Korolewicz, Teofil; Zołotajkin, Maria; Simka, Wojciech; Raczek, Malwina

    2013-01-01

    A new adsorbent based on natural clinoptilolite and amorphous zirconium dioxide (ZrO2) was prepared for the uptake of boron from fresh water. The sorption behaviour of this adsorbent for boron was investigated using a batch system and found to obey Langmuir, Freundlich and Dubinin-Radushkevich (D-R) isotherm models. The ZrO2 loading level, pH, temperature, contact time, initial boron concentration and adsorbent dose, on the removal of boron were studied. It was found that the removal of boron increased while the adsorbent dose increased and the temperature decreased at an optimum pH (pH = 8) and a contact time of 30 min. At optimum conditions, the maximum boron percentage removal was 75%. According to the D-R model, the maximum capacity was estimated to be > 3 mg B/g of the adsorbent. The adsorption energy value (calculated as 9.13 kJ/mol) indicated that the adsorption of boron on clinoptilolite modified with ZrO2 was physical in nature. The parameters of the adsorption models and the pH investigations pointed to the possibility of a chemisorption process. The thermodynamic parameters (standard entropy deltaS degrees, enthalpy deltaH degrees , and free energy deltaG degrees changes) of boron adsorption were also calculated. The negative value of deltaS degrees indicated a decreased randomness at the solid-solution interface during the boron adsorption. Negative values of deltaH degrees showed the exothermic nature of the process. The negative values of deltaG degrees implied that the adsorption of boron on clinoptilolite modified with amorphous ZrO2 at 25 degrees C was spontaneous. It was considered that boron dissolved in water had been adsorbed both physically and chemically on clinoptilolite modified with 30% ZrO2. PMID:24191469

  14. Extracting uranium from seawater: Promising AF series adsorbents

    SciTech Connect

    Das, Sadananda; Oyola, Y.; Mayes, Richard T.; Janke, Christopher James; Kuo, Li-Jung; Gill, Gary; Wood, Jordana; Dai, Sheng

    2015-11-02

    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.

  15. Extracting uranium from seawater: Promising AF series adsorbents

    DOE PAGES

    Das, Sadananda; Oyola, Y.; Mayes, Richard T.; Janke, Christopher James; Kuo, Li-Jung; Gill, Gary; Wood, Jordana; Dai, Sheng

    2015-11-02

    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 8more » 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.« less

  16. Adsorbent selection for endosulfan removal from water environment.

    PubMed

    Sudhakar, Y; Dikshit, A K

    1999-01-01

    In the present study, an attempt was made to select a low cost adsorbing material for the removal of endosulfan [C,C'-(1,4,5,6,7,7-hexachloro-8,9,10- trinorborn-5-en-2,3-ylene)(dimethylsulphite)] from water. Various low cost adsorbents like wood charcoal, kimberlite tailings, silica, macro fungi sojar caju were tried with activated charcoal as reference material. The above materials were selected from various sources encompassing organic, inorganic, clayey, and biological sources. For the selection of suitable adsorbent for endosulfan uptake, maximum adsorption capacity (Qmax) was chosen as the parameter. Kinetic profiles of removal were generated for all the materials to assess the equilibrium time. Equilibrium studies were carried out for all materials to assess the adsorption equilibrium model that they followed. The model that gave the best correlation coefficient by linear regression analysis, was adopted for the calculation of Qmax of the corresponding adsorbent material. Using linearised forms of equilibrium models like Langmuir, BET, and Freundlich, maximum adsorptive capacities were determined. Activated charcoal showed the best adsorptive capacity with Qmax of 2.145 mg/g followed by wood charcoal 1.773 mg/g, sojar caju 1.575 mg/g, kimberlite tailings 0.8821 mg/g, and silica 0.3231 mg/g. Albeit activated charcoal gave better performance, it was not considered as a candidate material because of its high cost. Wood charcoal was the next best adsorbent with Qmax 1.773 mg/g. Therefore, wood charcoal was chosen as the best material for endosulfan removal. The study of physical and chemical characteristics of wood charcoal revealed that it is a potential adsorbent and can even be improved further. PMID:10048207

  17. Nanoscale Probing of Adsorbed Species by Tip-Enhanced Raman Spectroscopy

    NASA Astrophysics Data System (ADS)

    Pettinger, Bruno; Ren, Bin; Picardi, Gennaro; Schuster, Rolf; Ertl, Gerhard

    2004-03-01

    Tip-enhanced Raman spectroscopy (TERS) is based on the optical excitation of localized surface plasmons in the tip-substrate cavity, which provides a large but local field enhancement near the tip apex. We report on TERS with smooth single crystalline surfaces as substrates. The adsorbates were CN- ions at Au(111) and malachite green isothiocyanate (MGITC) molecules at Au(111) and Pt(110) using either Au or Ir tips. The data analysis yields Raman enhancements of about 4×105 for CN- and up to 106 for MGITC at Au(111) with a Au tip, probing an area of less than 100nm radius.

  18. Adsorption Removal of Environmental Hormones of Dimethyl Phthalate Using Novel Magnetic Adsorbent.

    PubMed

    Chang, Chia-Chi; Tseng, Jyi-Yeong; Ji, Dar-Ren; Chiu, Chun-Yu; Lu, De-Sheng; Chang, Ching-Yuan; Yuan, Min-Hao; Chang, Chiung-Fen; Chiou, Chyow-San; Chen, Yi-Hung; Shie, Je-Lueng

    2015-01-01

    Magnetic polyvinyl alcohol adsorbent M-PVAL was employed to remove and concentrate dimethyl phthalate DMP. The M-PVAL was prepared after sequential syntheses of magnetic Fe3O4 (M) and polyvinyl acetate (M-PVAC). The saturated magnetizations of M, M-PVAC, and M-PVAL are 57.2, 26.0, and 43.2 emu g(-1) with superparamagnetism, respectively. The average size of M-PVAL by number is 0.75 μm in micro size. Adsorption experiments include three cases: (1) adjustment of initial pH (pH0) of solution to 5, (2) no adjustment of pH0 with value in 6.04-6.64, and (3) adjusted pH0 = 7. The corresponding saturated amounts of adsorption of unimolecular layer of Langmuir isotherm are 4.01, 5.21, and 4.22 mg g(-1), respectively. Values of heterogeneity factor of Freundlich isotherm are 2.59, 2.19, and 2.59 which are greater than 1, revealing the favorable adsorption of DMP/M-PVAL system. Values of adsorption activation energy per mole of Dubinin-Radushkevich isotherm are, respectively, of low values of 7.04, 6.48, and 7.19 kJ mol(-1), indicating the natural occurring of the adsorption process studied. The tiny size of adsorbent makes the adsorption take place easily while its superparamagnetism is beneficial for the separation and recovery of micro adsorbent from liquid by applying magnetic field after completion of adsorption. PMID:26258169

  19. Determinants of protein elution rates from preparative ion-exchange adsorbents.

    PubMed

    Angelo, James M; Lenhoff, Abraham M

    2016-04-01

    The rate processes involved in elution in preparative chromatography can affect both peak resolution and hence selectivity as well as practical factors such as facility fit. These processes depend on the physical structure of the adsorbent particles, the amount of bound solute, the solution conditions for operation or some combination of these factors. Ion-exchange adsorbents modified with covalently attached or grafted polymer layers have become widely used in preparative chromatography. Their often easily accessible microstructures offer substantial binding capacities for biomolecules, but elution has sometimes been observed to be undesirably slow. In order to determine which physicochemical phenomena control elution behavior, commercially available cellulosic, dextran-grafted and unmodified agarose materials were characterized here by their elution profiles at various conditions, including different degrees of loading. Elution data were analyzed under the assumption of purely diffusion-limited control, including the role of pore structure properties such as porosity and tortuosity. In general, effective elution rates decreased with the reduction of accessible pore volume, but differences among different proteins indicated the roles of additional factors. Additional measurements and analysis, including the use of confocal laser scanning microscopy to observe elution within single chromatographic particles, indicated the importance of protein association within the particle during elution. The use of protein stabilizing agents was explored in systems presenting atypical elution behavior, and l-arginine and disaccharide excipients were shown to alleviate the effects for one protein, lysozyme, in the presence of sodium chloride. Incorporation of these excipients into eluent buffer gave rise to faster elution and significantly lower pool volumes in elution from polymer-modified adsorbents.

  20. Adsorption Removal of Environmental Hormones of Dimethyl Phthalate Using Novel Magnetic Adsorbent

    PubMed Central

    Chang, Chia-Chi; Tseng, Jyi-Yeong; Ji, Dar-Ren; Chiu, Chun-Yu; Lu, De-Sheng; Chang, Ching-Yuan; Yuan, Min-Hao; Chang, Chiung-Fen; Chiou, Chyow-San; Chen, Yi-Hung; Shie, Je-Lueng

    2015-01-01

    Magnetic polyvinyl alcohol adsorbent M-PVAL was employed to remove and concentrate dimethyl phthalate DMP. The M-PVAL was prepared after sequential syntheses of magnetic Fe3O4 (M) and polyvinyl acetate (M-PVAC). The saturated magnetizations of M, M-PVAC, and M-PVAL are 57.2, 26.0, and 43.2 emu g−1 with superparamagnetism, respectively. The average size of M-PVAL by number is 0.75 μm in micro size. Adsorption experiments include three cases: (1) adjustment of initial pH (pH0) of solution to 5, (2) no adjustment of pH0 with value in 6.04–6.64, and (3) adjusted pH0 = 7. The corresponding saturated amounts of adsorption of unimolecular layer of Langmuir isotherm are 4.01, 5.21, and 4.22 mg g−1, respectively. Values of heterogeneity factor of Freundlich isotherm are 2.59, 2.19, and 2.59 which are greater than 1, revealing the favorable adsorption of DMP/M-PVAL system. Values of adsorption activation energy per mole of Dubinin-Radushkevich isotherm are, respectively, of low values of 7.04, 6.48, and 7.19 kJ mol−1, indicating the natural occurring of the adsorption process studied. The tiny size of adsorbent makes the adsorption take place easily while its superparamagnetism is beneficial for the separation and recovery of micro adsorbent from liquid by applying magnetic field after completion of adsorption. PMID:26258169

  1. Optimisation of the detection of bacterial proteases using adsorbed immunoglobulins as universal substrates.

    PubMed

    Abuknesha, Ram A; Jeganathan, Fiona; Wildeboer, Dirk; Price, Robert G

    2010-06-15

    Bacterial proteases, Type XXIV from Bacillus licheniformens and Type XIV from Streptomyces griseus, were used to investigate the utility and optimisation of a solid phase assay for proteases, using immunoglobulin proteins as substrates. Immunoglobulins IgA and IgG were adsorbed on to surfaces of ELISA plates and exposed to various levels of the bacterial proteases which led to digestion and desorption of proportional amounts of the immunoglobulins. The assay signal was developed by measuring the remaining proteins on the polystyrene surface with appropriate enzyme-labelled anti-immunoglobulin reagents. The assay was fully optimised in terms of substrate levels employing ELISA techniques to titrate levels of adsorbed substrates and protease analytes. The critical factor which influences assay sensitivity was found to be the substrate concentration, the levels of adsorbed immunoglobulins. The estimated detection limits for protease XXIV and XIV were 10micro units/test and 9micro units/test using IgA as a substrate. EC(50) values were calculated as 213 and 48micro units/test for each protease respectively. Using IgG as a substrate, the estimated detection limits were 104micro units/test for protease XXIV and 9micro units/test for protease XIV. EC(50) values were calculated at 529micro units/test and 28micro units/test for protease XXIV and XIV respectively. The solid phase protease assay required no modification of the substrates and the adsorption step is merely simple addition of immunoglobulins to ELISA plates. Adsorption of the immunoglobulins to polystyrene enabled straightforward separation of reaction mixtures prior to development of assay signal. The assay exploits the advantages of the technical facilities of ELISA technology and commercially available reagents enabling the detection and measurement of a wide range of proteases. However, the key issue was found to be that in order to achieve the potential performance of the simple assay, optimisation of the

  2. Nature, strength, and consequences of indirect adsorbate interactions on metals

    SciTech Connect

    BOGICEVIC,ALEXANDER; OVESSON,S.; HYLDGAARD,P.; LUNDQVIST,B.I.; JENNISON,DWIGHT R.

    2000-02-14

    Atoms and molecules adsorbed on metals affect each other even over considerable distances. In a tour-de-force of density-functional methods, the authors establish the nature and strength of such indirect interactions, and explain for what adsorbate systems they can critically affect important materials properties. These perceptions are verified in kinetic Monte Carlo simulations of epitaxial growth, and help rationalize a cascade of recent experimental reports on anomalously low diffusion prefactors. The authors focus their study on two metal systems: Al/Al(111) and Cu/Cu(111).

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

    NASA Astrophysics Data System (ADS)

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

    2010-08-01

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

  4. Carbon adsorbents from products of solid fuel processing

    SciTech Connect

    Pokonova, Yu.V.; Grabovskii, A.I.

    1995-01-10

    Total shale phenols (mixture of alkylresorcinols) or their solution in commercial-grade furfural can be used for forming carbon adsorbents with high mechanical strength (up to 97%), high microporosity (up to 0.41 cm{sup 3}{center_dot}cm{sup -3}), and higher sorption capacity. Samples with medium burnout exhibit higher selectivity (than those molded from conventional wood tar) in the recovery of noble metals from multicomponent metal salt solutions. In these parameters they surpass commercial adsorbents as well. Samples with low burnout exhibit high selectivity and separation ability with respect to gas mixtures.

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

    USGS Publications Warehouse

    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.

  6. Structural characterization of adsorbed helical and beta-sheet peptides

    NASA Astrophysics Data System (ADS)

    Samuel, Newton Thangadurai

    Adsorbed peptides on surfaces have potential applications in the fields of biomaterials, tissue engineering, peptide microarrays and nanobiotechnology. The surface region, the "biomolecular interface" between a material and the biological environment, plays a crucial role in these applications. As a result, characterization of adsorbed peptide structure, especially with respect to identity, concentration, spatial distribution, conformation and orientation, is important. The present research employs NEXAFS (near-edge X-ray absorption fine structure spectroscopy) and SFG (sum frequency generation spectroscopy) to provide information about the adsorbed peptide structure. Soft X-ray NEXAFS is a synchrotron-based technique which typically utilizes polarized X-rays to interrogate surfaces under ultra-high vacuum conditions. SFG is a non-linear optical technique which utilizes a combination of a fixed visible and a tunable infrared laser beams to generate a surface-vibrational spectrum of surface species. SFG has the added advantage of being able to directly analyze the surface-structure at the solid-liquid interface. The main goals of the present research were twofold: characterize the structure of adsorbed peptides (1) ex situ using soft X-ray NEXAFS, and (2) in situ using non-linear laser spectroscopy (SFG). Achieving the former goal involved first developing a comprehensive characterization of the carbon, nitrogen and oxygen k-edge NEXAFS spectra for amino acids, and then using a series of helical and beta-sheet peptides to demonstrate the sensitivity of polarization-dependent NEXAFS to secondary structure of adsorbed peptides. Characterizing the structure of adsorbed peptides in situ using SFG involved developing a model system to probe the solid-liquid interface in situ; demonstrating the ability to probe the molecular interactions and adsorbed secondary structure; following the time-dependent ordering of the adsorbed peptides; and establishing the ability to obtain

  7. Affinity Adsorbents Based on Carriers Activated by Epoxy-compounds

    NASA Astrophysics Data System (ADS)

    Klyashchitskii, B. A.; Kuznetsov, P. V.

    1984-10-01

    The review is devoted to the synthesis and applications of affinity adsorbents based on carriers activated by epoxy-compounds. The methods for the introduction of epoxy-groups into carriers of different chemical types are discussed and conditions for the immobilisation of three-dimensional spacers and low-molecular-weight and polymeric ligands on carriers containing epoxy-groups are considered. Data are presented on the properties and applications of adsorbents of this type in affinity chromatography. The bibliography includes 144 references.

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

    NASA Astrophysics Data System (ADS)

    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.

  9. 24 CFR 576.45 - Reallocation of grant amounts; returned or unused amounts.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 24 Housing and Urban Development 3 2011-04-01 2010-04-01 true Reallocation of grant amounts; returned or unused amounts. 576.45 Section 576.45 Housing and Urban Development Regulations Relating to Housing and Urban Development (Continued) OFFICE OF ASSISTANT SECRETARY FOR COMMUNITY PLANNING...

  10. 29 CFR 4219.13 - Amount of liability for de minimis amounts.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 29 Labor 9 2013-07-01 2013-07-01 false Amount of liability for de minimis amounts. 4219.13 Section 4219.13 Labor Regulations Relating to Labor (Continued) PENSION BENEFIT GUARANTY CORPORATION WITHDRAWAL LIABILITY FOR MULTIEMPLOYER PLANS NOTICE, COLLECTION, AND REDETERMINATION OF WITHDRAWAL...

  11. 29 CFR 4219.13 - Amount of liability for de minimis amounts.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 29 Labor 9 2012-07-01 2012-07-01 false Amount of liability for de minimis amounts. 4219.13 Section 4219.13 Labor Regulations Relating to Labor (Continued) PENSION BENEFIT GUARANTY CORPORATION WITHDRAWAL LIABILITY FOR MULTIEMPLOYER PLANS NOTICE, COLLECTION, AND REDETERMINATION OF WITHDRAWAL...

  12. 29 CFR 4219.13 - Amount of liability for de minimis amounts.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 29 Labor 9 2010-07-01 2010-07-01 false Amount of liability for de minimis amounts. 4219.13 Section 4219.13 Labor Regulations Relating to Labor (Continued) PENSION BENEFIT GUARANTY CORPORATION WITHDRAWAL LIABILITY FOR MULTIEMPLOYER PLANS NOTICE, COLLECTION, AND REDETERMINATION OF WITHDRAWAL...

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

    PubMed

    Ansari, Adil; Bandosz, Teresa J

    2005-08-15

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

  14. Removal of Direct Red 12B by garlic peel as a cheap adsorbent: Kinetics, thermodynamic and equilibrium isotherms study of removal

    NASA Astrophysics Data System (ADS)

    Asfaram, A.; Fathi, M. R.; Khodadoust, S.; Naraki, M.

    2014-06-01

    The removal of dyes from industrial waste is very important from health and hygiene point of view and for environmental protection. In this work, efficiency and performance of garlic peel (GP) adsorbent for the removal of Direct Red 12B (DR12B) from wastewater was investigated. The influence of variables including pH, concentration of the dye and amount of adsorbent, particle size, contact time and temperature on the dye removal has been investigated. It was observed that the pseudo-second-order kinetic model fits better with good correlation coefficient and the equilibrium data fitted well with the Langmuir model. More than 99% removal efficiency was obtained within 25 min at adsorbent dose of 0.2 g per 50 ml for initial dye concentration of 50 mg L-1. Calculation of various thermodynamic parameters such as, Gibb's free energy, entropy and enthalpy of the on-going adsorption process indicate feasibility and endothermic nature of DR12B adsorption.

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

    PubMed

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

    2012-11-01

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

  16. Cadmium telluride nanoparticles loaded on activated carbon as adsorbent for removal of sunset yellow

    NASA Astrophysics Data System (ADS)

    Ghaedi, M.; Hekmati Jah, A.; Khodadoust, S.; Sahraei, R.; Daneshfar, A.; Mihandoost, A.; Purkait, M. K.

    2012-05-01

    Adsorption is a promising technique for decolorization of effluents of textile dyeing industries but its application is limited due to requirement of high amounts of adsorbent required. The objective of this study was to assess the potential of cadmium telluride nanoparticles loaded onto activated carbon (CdTN-AC) for the removal of sunset yellow (SY) dye from aqueous solution. Adsorption studies were conducted in a batch mode varying solution pH, contact time, initial dye concentration, CdTN-AC dose, and temperature. In order to investigate the efficiency of SY adsorption on CdTN-AC, pseudo-first-order, pseudo-second-order, Elovich, and intra-particle diffusion kinetic models were studied. It was observed that the pseudo-second-order kinetic model fits better than other kinetic models with good correlation coefficient. Equilibrium data were fitted to the Langmuir model. Thermodynamic parameters such as enthalpy, entropy, activation energy, and sticking probability were also calculated. It was found that the sorption of SY onto CdTN-AC was spontaneous and endothermic in nature. The proposed adsorbent is applicable for SY removal from waste of real effluents including pea-shooter, orange drink and jelly banana with efficiency more than 97%.

  17. Mutagenicity of organic pollutants adsorbed on suspended particulate matter in the center of Wrocław (Poland)

    NASA Astrophysics Data System (ADS)

    Bełcik, Maciej; Trusz-Zdybek, Agnieszka; Galas, Ewa; Piekarska, Katarzyna

    2014-10-01

    Mutagenicity of pollutants adsorbed on suspended dust of the PM10 fraction, collected in winter and summer season alike over the Wrocław city centre (Poland) was studied using the standard Salmonella assay (plate-incorporation) and the Kado modified assay (microsuspension method). The dust was collected using Staplex high volume air sampler. Further on it was extracted with dichloromethane in a Soxhlet apparatus. PAH content in extracts was determined by the high performance liquid chromatography technique using fluorescence detection, whereas the nitro-PAH content- by the gas chromatography using mass detection. Two Salmonella typhimurium strains, TA98 and YG1041, were used in the assays. The assays were conducted with and without a metabolic activation. Investigated air pollution extracts differed against each other with regard to a total content as well as to a percentage of individual compounds, depending on the sampling season. Both the total PAH content and the nitro-PAH content in the tested samples, and their spectrum as well, were found the highest in winter season. Higher mutagenic effect was noted for the dust extract from samples collected in wintertime than from those collected in summer. Pollutants directly affecting the genetic material and those showing such indirect action were present in the examined samples. The YG1041 strain turned out to be the most sensitive, which was the sign that large amounts of nitro-aromatic compounds were present in the tested samples. Obtained results proved that the Kado modified Salmonella assay would be useful for the atmospheric air pollution monitoring in urban agglomerations. Mutagenic effect in assays conducted according to the Kado procedure was obtained by using in the assays lower concentrations of tested extracts, compared to the classical assay.

  18. Extracting uranium from seawater: Promising AI series adsorbents

    DOE PAGES

    Das, Sadananda; Oyola, Y.; Mayes, Richard T.; Janke, Christopher James; Kuo, Li-Jung; Gill, Gary; Wood, Jordana; Dai, Sheng

    2015-11-10

    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 frommore » 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.« less

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

    EPA Science Inventory

    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...

  20. Activation volumes of enzymes adsorbed on silica particles.

    PubMed

    Schuabb, Vitor; Czeslik, Claus

    2014-12-30

    The immobilization of enzymes on carrier particles is useful in many biotechnological processes. In this way, enzymes can be separated from the reaction solution by filtering and can be reused in several cycles. On the other hand, there is a series of examples of free enzymes in solution that can be activated by the application of pressure. Thus, a potential loss of enzymatic activity upon immobilization on carrier particles might be compensated by pressure. In this study, we have determined the activation volumes of two enzymes, α-chymotrypsin (α-CT) and horseradish peroxidase (HRP), when they are adsorbed on silica particles and free in solution. The experiments have been carried out using fluorescence assays under pressures up to 2000 bar. In all cases, activation volumes were found to depend on the applied pressure, suggesting different compressions of the enzyme-substrate complex and the transition state. The volume profiles of free and adsorbed HRP are similar. For α-CT, larger activation volumes are found in the adsorbed state. However, up to about 500 bar, the enzymatic reaction of α-CT, which is adsorbed on silica particles, is characterized by a negative activation volume. This observation suggests that application of pressure might indeed be useful to enhance the activity of enzymes on carrier particles.

  1. Interactions of organic contaminants with mineral-adsorbed surfactants

    USGS Publications Warehouse

    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.

  2. RADIOLYSIS OF ORGANIC COMPOUNDS IN THE ADSORBED STATE

    DOEpatents

    Sutherland, J.W.; Allen, A.O.

    1961-10-01

    >A method of forming branch chained hydrocarbons by means of energetic penetrating radiation is described. A solid zeolite substrate is admixed with a cobalt ion and is irradiated with a hydrocarbon adsorbed therein. Upon irradiation with gamma rays, there is an increased yield of branched and lower molecular straight chain compounds. (AEC)

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

    Technology Transfer Automated Retrieval System (TEKTRAN)

    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...

  4. Hydraulic properties of adsorbed water films in unsaturated porous media

    SciTech Connect

    Tokunaga, Tetsu K.

    2009-03-01

    Adsorbed water films strongly influence residual water saturations and hydraulic conductivities in porous media at low saturations. Hydraulic properties of adsorbed water films in unsaturated porous media were investigated through combining Langmuir's film model with scaling analysis, without use of any adjustable parameters. Diffuse double layer influences are predicted to be important through the strong dependence of adsorbed water film thickness (f) on matric potential ({Psi}) and ion charge (z). Film thickness, film velocity, and unsaturated hydraulic conductivity are predicted to vary with z{sup -1}, z{sup -2}, and z{sup -3}, respectively. In monodisperse granular media, the characteristic grain size ({lambda}) controls film hydraulics through {lambda}{sup -1} scaling of (1) the perimeter length per unit cross sectional area over which films occur, (2) the critical matric potential ({Psi}{sub c}) below which films control flow, and (3) the magnitude of the unsaturated hydraulic conductivity when {Psi} < {Psi}{sub c}. While it is recognized that finer textured sediments have higher unsaturated hydraulic conductivities than coarser sands at intermediate {Psi}, the {lambda}{sup -1} scaling of hydraulic conductivity predicted here extends this understanding to very low saturations where all pores are drained. Extremely low unsaturated hydraulic conductivities are predicted under adsorbed film-controlled conditions (generally < 0.1 mm y{sup -1}). On flat surfaces, the film hydraulic diffusivity is shown to be constant (invariant with respect to {Psi}).

  5. Gd uptake experiments for preliminary set of functionalized adsorbents

    SciTech Connect

    Clinton Noack

    2015-03-16

    These data summarize adsorption experiments conducted with Gd in 0.5 M NaCl. Results represent preliminary, proof-of-concept data utilizing fine-powder silica gel as the adsorbent support. Future testing will focus on larger, application-appropriate beads.

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

    NASA Astrophysics Data System (ADS)

    Pflieger, Maryline; Grgić, Irena; Kitanovski, Zoran

    2012-12-01

    The results on heterogeneous ozonation of a phenylurea pesticide, isoproturon, under atmospheric conditions are presented for the first time in the present study. The study was carried out using an experimental device previously adopted and validated for the heterogeneous reactivity of organics toward ozone (Pflieger et al., 2011). Isoproturon was adsorbed on silica particles via a liquid-to-solid equilibrium with a load far below a monolayer (0.02% by weight/surface coverage of 0.5%). The rate constants were estimated by measuring the consumption of the organic (dark, T = 26 °C, RH < 1%). The experimental data were fitted by both the modified Langmuir-Hinshelwood and the Eley-Rideal patterns, resulting in atmospheric lifetimes of heterogeneous ozonation of 4 and 6 days, respectively (for 40 ppb of O3). Parameters, such as the number and the quantity of pesticides adsorbed on the solid support, which can significantly influence the heterogeneous kinetics, were investigated as well. The results obtained suggest that the organic compound is adsorbed in multilayer aggregates on the aerosol even though submonolayer coverage is assumed. The presence of a second herbicide, trifluralin, together with isoproturon on the aerosol surface does not affect the kinetics of ozonation, indicating that both compounds are adsorbed on different surface sites of silica particles.

  7. Chitosan membrane adsorber for low concentration copper ion removal.

    PubMed

    Wang, Xiaomin; Li, Yanxiang; Li, Haigang; Yang, Chuanfang

    2016-08-01

    Thin chitosan membranes with symmetric and interconnected pore structure were prepared using silica as porogen, and their physical properties including pore structure, pore size distribution, porosity and water affinity were analyzed. The membrane showed a maximum Cu(II) adsorption capacity of 87.5mg/g in static adsorption, and the adsorption fitted pseudo-second order kinetics and Toth adsorption isotherm. The membranes were then stacked in layers as an adsorber to remove small concentration Cu(II) from water dynamically. At feed concentration of 5mg/L, the adsorber could retain Cu(II) effectively when its thickness reached over 200μm, and the performance was further improved by using more membranes layers. Within a certain limit, the adsorber showed a 'flow-independent' loading behavior, an indication of fast mass transfer inside the membrane. The adsorption process was correlated well with bed depth service time (BDST) model, Thomas model and Yoon and Nelson model, and the adsorber was also found to be regenerable and re-usable. PMID:27112875

  8. EMERGING TECHNOLOGY REPORT: DEMONSTRATION OF AMBERSORB™ 563 ADSORBENT TECHNOLOGY

    EPA Science Inventory

    The Ambersorb™ (Rohm and Haas) Adsorbent technology demonstration was conducted over a 12-week period during the spring/summer of 1994 at Site 32/36 of the former Pease Air Force Base, Newington, N.H. The groundwater in this area is contaminated with a number of chlorinated organ...

  9. Complexation of trace metals by adsorbed natural organic matter

    USGS Publications Warehouse

    Davis, J.A.

    1984-01-01

    The adsorption behavior and solution speciation of Cu(II) and Cd(II) were studied in model systems containing colloidal alumina particles and dissolved natural organic matter. At equilibrium a significant fraction of the alumina surface was covered by adsorbed organic matter. Cu(II) was partitioned primarily between the surface-bound organic matter and dissolved Cu-organic complexes in the aqueous phase. Complexation of Cu2+ with the functional groups of adsorbed organic matter was stronger than complexation with uncovered alumina surface hydroxyls. It is shown that the complexation of Cu(II) by adsorbed organic matter can be described by an apparent stability constant approximately equal to the value found for solution phase equilibria. In contrast, Cd(II) adsorption was not significantly affected by the presence of organic matter at the surface, due to weak complex formation with the organic ligands. The results demonstrate that general models of trace element partitioning in natural waters must consider the presence of adsorbed organic matter. ?? 1984.

  10. Extracting uranium from seawater: Promising AI series adsorbents

    SciTech Connect

    Das, Sadananda; Oyola, Y.; Mayes, Richard T.; Janke, Christopher James; Kuo, Li-Jung; Gill, Gary; Wood, Jordana; Dai, Sheng

    2015-11-10

    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.

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

    Technology Transfer Automated Retrieval System (TEKTRAN)

    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...

  12. DESIGNING FIXED-BED ADSORBERS TO REMOVE MIXTURES OF ORGANICS.

    EPA Science Inventory

    A liquid-phase granular activated carbon (GAC) pilot plant and a full-scale GAC adsorber were designed, built, and operated in order to evaluate their performance for treating a groundwater contaminated with several volatile and synthetic organic chemicals. Several empty bed con...

  13. Interactions of organic contaminants with mineral-adsorbed surfactants.

    PubMed

    Zhu, Lizhong; Chen, Baoliang; Tao, Shu; Chiou, Cary T

    2003-09-01

    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 insightto 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.

  14. Characterization of iron oxide nanoparticles adsorbed with cisplatin for biomedical applications

    NASA Astrophysics Data System (ADS)

    Kettering, Melanie; Zorn, Heike; Bremer-Streck, Sibylle; Oehring, Hartmut; Zeisberger, Matthias; Bergemann, Christian; Hergt, Rudolf; Halbhuber, Karl-Jürgen; Kaiser, Werner A.; Hilger, Ingrid

    2009-09-01

    The aim of this study was to characterize the behaviour of cisplatin adsorbed magnetic nanoparticles (cis-MNPs) for minimal invasive cancer treatments in preliminary in vitro investigations. Cisplatin was adsorbed to magnetic nanoparticles (MNPs) by simple incubation. For stability determinations, cis-MNPs were incubated in dH2O, phosphate-buffered saline (PBS) and fetal calf serum (FCS) at 4-121 °C up to 20 weeks. Hydrodynamic diameters were measured using laser diffraction. The extent of cisplatin linkage was determined by atomic absorption spectrometry. The magnetite core size was assessed by vibrating sample magnetometry and transmission electron microscopy. The specific loss power (SLP) was measured in an alternating magnetic field. Our results showed that a maximum of 10.3 ± 1.6 (dH2O), 10 ± 1.6 (PBS) and 13.4 ± 2.2 (FCS) mg cisplatin g-1 Fe could be adsorbed to MNPs. With hyperthermal (42 °C) or thermal ablative (60 °C) temperatures, used for therapeutic approaches, cisplatin did not desorb from cis-MNPs in dH2O during incubation times of 180 or 30 min, respectively. In PBS and FCS, cisplatin amounts adsorbed to MNPs decreased rapidly to approximately 50% and 25% at these temperatures. This cisplatin release will be necessary for successful chemotherapeutic activity and should increase the therapeutic effect of magnetic heating treatment in medicinal applications. The hydrodynamic diameters of MNPs or cis-MNPs were around 70 nm and magnetization data showed superparamagnetic behaviour. The obtained mean core diameter was around 12 nm. The SLP of the sample was calculated to be 75.5 ± 1.6 W g-1. In conclusion, cis-MNPs exhibit advantageous features for a facilitated desorption of cisplatin in biological media and the heating potential is adequate for hyperthermic treatments. Therefore, even though further detailed investigations are still necessary, tentative use in local tumour therapies aiming at a specific chemotherapeutic release in combination

  15. Nanopore reactive adsorbents for the high-efficiency removal of waste species

    DOEpatents

    Yang, Arthur Jing-Min; Zhang, Yuehua

    2005-01-04

    A nanoporous reactive adsorbent incorporates a relatively small number of relatively larger reactant, e.g., metal, enzyme, etc., particles (10) forming a discontinuous or continuous phase interspersed among and surrounded by a continuous phase of smaller adsorbent particles (12) and connected interstitial pores (14) therebetween. The reactive adsorbent can effectively remove inorganic or organic impurities in a liquid by causing the liquid to flow through the adsorbent. For example, silver ions may be adsorbed by the adsorbent particles (12) and reduced to metallic silver by reducing metal, such as ions, as the reactant particles (10). The column can be regenerated by backwashing with the liquid effluent containing, for example, acetic acid.

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

    PubMed

    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

  17. Possibility of observable amount of gravitational waves from inflation.

    PubMed

    Pilo, L; Riotto, A; Zaffaroni, A

    2004-05-21

    The curvaton and inhomogeneous reheating scenarios for the generation of the cosmological curvature perturbation on large scales represent an alternative to the standard slow-roll scenario. The basic assumption of these mechanisms is that the initial curvature perturbation due to the inflaton field is negligible. This is usually attained by lowering the energy scale of inflation, thereby concluding that the amount of gravitational waves produced during inflation is highly suppressed. We show that the curvaton and inhomogeneous reheating scenarios are compatible with a level of gravity-wave fluctuations which may well be observed in future satellite experiments.

  18. [Amount and quality of food advertisement on Brazilian television].

    PubMed

    Almeida, Sebastião de Sousa; Nascimento, Paula Carolina B D; Quaioti, Teresa Cristina Bolzan

    2002-06-01

    The main objective of the study was to analyze the amount and quality of food advertisement on Brazilian television in three different times of the day. The results showed that food products, when compared to other products, were the most frequently advertised, regardless of the time of the day in a given week analyzed. Television promotes food predominantly high in fat and/or sugar and salt. The large number of high fat and/or sugar and salt products advertised can contribute to changing food habits of children and teenagers, and increasing the incidence of obesity in the population.

  19. Case studies for heavy metals removal using a granular, magnesium-based adsorbent

    SciTech Connect

    Walter, M.D.; Witkowski, J.T.; Reyes, A.

    1994-12-31

    Environmental regulations have become increasingly severe regarding the types and amounts of pollutants that may be released into the environment. In particular, metal finishers are commonly restricted to the metal concentrations and pH of waste water that may be discharged into natural waterways, municipal sewers, etc. This paper details a granular Magnesium-based Adsorbent (FloMag{trademark} G) which has been used to remove various metals from surface finishing waste water streams. The metals treated in this study include copper, nickel, and zinc. Effluent concentrations of the treated metals are typically less than 0.5 mg/L. Three case studies are presented detailing the performance of FloMag{trademark} G as well as information about how FloMag{trademark} G removes metals from solution.

  20. Column preconcentration and faas determination of heavy metal ions using Artemisia Siberi as an adsorbent.

    PubMed

    Mousavi, Hassan Zavvar; Derakhshankhah, Jalal

    2014-01-01

    A new column procedure for the determination of trace amounts of cadmium (II), lead (II), nickel (II), zinc (II), and copper (II), which combines flame atomic absorption spectrometry is described. These metals were sorbed on Artemisia siberi herb as an adsorbent at pH 4.0 and eluted with 3 mL of 1.5 M HNO3. The influences of analytical parameters including pH, flow rate, sample volume, type of eluent, and effect of diverse salts and cations on the recoveries of analyte ions were studied. The developed procedure provides preconcentration factors of about 117. LODs were 0.2 (Cd), 0.4 (Cu), 0.2 (Ni), 0.6 (Zn), and 1.4 (Pb) μg/L. The present method was successfully applied to the determination of the above-mentioned ions in water samples from Semnan, Iran. Recoveries greater than 95% and RSDs below 10% were obtained. PMID:25632447

  1. Protein immobilization in hollow nanostructures and investigation of the adsorbed protein behavior.

    PubMed

    Qian, Xi; Levenstein, Alex; Gagner, Jennifer E; Dordick, Jonathan S; Siegel, Richard W

    2014-02-11

    Understanding nanomaterial-biomolecule interactions is critical to develop broad applications in sensors, devices, and therapeutics. During the past decade, in-depth studies have been performed on the effect of nanoscale surface topography on adsorbed protein structure and function. However, a fundamental understanding of nanobio interactions at concave surfaces is limited; the greatest challenge is to create a nanostructure that allows such interactions to occur and to be characterized. We have synthesized hollow nanocages (AuNG) through careful control of morphology and surface chemistry. Lysozyme was used as a model to probe interactions between a protein and these nanostructures. Solid Au nanoparticles with a similar morphology and surface chemistry were also used as a reference. Through a series of quantitative analyses of protein adsorption profiles and enzymatic activity assays of both nanobioconjugates, we discovered that a significant amount of protein could be delivered into the core of AuNG, while maintaining a substantial fraction of native activity.

  2. Adsorbable organic halogens generation and reduction during degradation of phenol by UV radiation/sodium hypochlorite.

    PubMed

    Zeng, Qing-Fu; Fu, Jie; Shi, Yin-Tao; Xia, Dong-Sheng; Zhu, Hai-Liang

    2009-02-01

    The degradation of phenol by UV radiation/sodium hypochlorite (UV/NaClO) was investigated. The degradation processes were analyzed by a UV-visible spectrometer, total organic carbon analyzer, and gas chromatography-mass spectroscopy. The experimental results indicate that phenol can be photodegraded by UV/NaClO effectively. However, adsorbable organic halogens (AOX) were produced during the degradation process. Analysis of the mechanism of degradation indicates that the decrease in pH value would increase the formation of AOX. Also, dissolved oxygen greatly increased the rate of phenol degradation and reduced the formation of AOX. Therefore, appropriate conditions could increase degradation and inhibit chlorination. Adjusting the pH value and increasing the amount of oxygen were effective methods.

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

    SciTech Connect

    Li, Tsung-Lung; Lu, Wen-Cai

    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

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

    NASA Astrophysics Data System (ADS)

    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

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

    PubMed

    Li, Tsung-Lung; Lu, Wen-Cai

    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 (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

  6. The amount of heat resources and available heat of treated sewage

    SciTech Connect

    Cho, M.K.; Cho, C.G.; Pang, S.K.

    1999-07-01

    The purpose of this research is to understand the amount of regional heat resources from treated sewage, and present the heat resources data available to develop a heat recovery system. In this study, the amount of treated sewage in disposal plants are investigated on a nationwide scale in seven large cities and nine provinces in Korea. As the result of this study, the amount of treated sewage was determined to be 3,223,572,000 ton/year on a nationwide scale, and the quantity of it amounted to 73.6% in large cities including Seoul. The location of sewage disposal plants and the amount of heat resources were visualized on the map using a GIS database of them on personal computer. The amount of available heat resources turned out to be enormous, a capacity equivalent to 45 Mcal/month in the case of Taejon city.

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

    PubMed

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

    2011-10-01

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

  8. Effect of habitat amount, configuration and quality in fragmented landscapes

    NASA Astrophysics Data System (ADS)

    Mortelliti, Alessio; Sozio, Giulia; Boccacci, Francesca; Ranchelli, Elisa; Cecere, Jacopo G.; Battisti, Corrado; Boitani, Luigi

    2012-11-01

    Landscape changes are driven by several factors, such as habitat loss, fragmentation and degradation. Untangling the independent contribution of each process is crucial, since effective conservation actions depend on the clear identification of the threatening process. Nevertheless in most landscape scale studies configuration metrics are often grouped together without further distinguishing between different habitat properties (e.g. subdivision vs scatteredness of habitat patches) furthermore few landscape scale studies have included measurements of habitat quality thus possibly overlooking important interactions with landscape structure. In order to tackle these issues we carried out a large scale field study following an experimental design that allowed us to disentangle the independent role of landscape processes. We chose the European reed warbler (Acrocephalus scirpaceus) as model species due to its ecological characteristics. Probability of the reed warbler presence increased in landscapes with increasing amounts of habitat and increased with the proportion of flooded reed bed patches in the landscape; variables related to the configuration of habitat, instead, did not play a relevant role in shaping distribution patterns. Results of the modelling inference revealed a crucial complementarity between habitat quality and landscape structure: regulation of the amount of water in the canals increased the habitat suitability of patches only for landscapes with intermediate amounts of habitat.

  9. Magnetic nano graphene oxide as solid phase extraction adsorbent coupled with liquid chromatography to determine pseudoephedrine in urine samples.

    PubMed

    Taghvimi, Arezou; Hamishehkar, Hamed; Ebrahimi, Mahmoud

    2016-01-15

    This paper reports on a method based on magnetic solid phase extraction (MSPE) for the determination of pseudoephedrine. Magnetic nanographene oxide (MNGO) was applied as a new adsorbent for the extraction of pseudoephedrine from urine samples. Synthesis of MNGO was characterized by Fourier transform infrared (FT-IR) spectroscopy, scanning electron microscopy (SEM), powder X-ray diffraction (XRD), and vibrating sample magnetometer (VSM). The main factors influencing extraction efficiency, including the amounts of sample volume, amount of adsorbent, type and amount of extraction organic solvent, time of extraction and desorption, pH, ionic strength of extraction medium, and agitation rate, were investigated and optimized. Under optimized extraction conditions, a good linearity was observed in the range of 100-2000ng/mL with a correlation coefficient of 0.9908 (r(2)). Limit of detection (LOD) and limit of quantification (LOQ) were 25 and 82.7ng/mL, respectively. Inter-day and intra-day precision and accuracy were 6.01 and 0.34 (%), and 8.70 and 0.29 (%), respectively. The method was applied for the determination of pseudoephedrine in urine samples of volunteers receiving pseudoephedrine with the recovery of 96.42. It was concluded that the proposed method can be applied in diagnostic clinics.

  10. Nanofiber adsorbents for high productivity continuous downstream processing.

    PubMed

    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

  11. Nuclear DNA Amounts in Macaronesian Angiosperms

    PubMed Central

    SUDA, JAN; KYNCL, TOMÁŠ; FREIOVÁ, RADKA

    2003-01-01

    Nuclear DNA contents for 104 Macaronesian angiosperms, with particular attention on Canary Islands endemics, were analysed using propidium iodide flow cytometry. Prime estimates for more than one‐sixth of the whole Canarian endemic flora (including representatives of 11 endemic genera) were obtained. The resulting 1C DNA values ranged from 0·19 to 7·21 pg for Descurainia bourgeauana and Argyranthemum frutescens, respectively (about 38‐fold difference). The majority of species, however, possessed (very) small genomes, with C‐values <1·6 pg. The tendency towards small nuclear DNA contents and genome sizes was confirmed by comparing average values for Macaronesian and non‐Macaronesian representatives of individual families, genera and major phylogenetic lineages. Our data support the hypothesis that the insular selection pressures in Macaronesia favour small C‐values and genome sizes. Both positive and negative correlations between infrageneric nuclear DNA amount variation and environmental conditions on Tenerife were also found in several genera. PMID:12824074

  12. Hollow-fiber-based adsorbers for gas separation by pressure-swing adsorption

    SciTech Connect

    Feng, X.; Pan, C.Y.; McMinis, C.W.; Ivory, J.; Ghosh, D.

    1998-07-01

    Hollow-fiber-based adsorbers for gas separation by pressure-swing adsorption (PSA) was studied experimentally. The high efficiency of hollow-fiber-based adsorbers for gas separation was illustrated by hydrogen separation using fine-powder-activated carbon and molecular sieve as adsorbents. The adsorption equilibrium and dynamics of the hollow-fiber adsorbers were determined. The pressure drop of the gas flowing through the adsorbers was also examined. The adsorbers were tested for hydrogen separation from nitrogen, carbon dioxide, and a multicomponent gas mixture simulating ammonia synthesis purge gas. The PSA systems using the hollow-fiber adsorbers were very effective for hydrogen purification. The high separation efficiency is derived from the fast mass-transfer rate and low pressure drop, two key features of hollow-fiber-based adsorbers.

  13. Detecting the mass and position of an adsorbate on a drum resonator

    PubMed Central

    Zhang, Y.; Zhao, Y. P.

    2014-01-01

    The resonant frequency shifts of a circular membrane caused by an adsorbate are the sensing mechanism for a drum resonator. The adsorbate mass and position are the two major (unknown) parameters determining the resonant frequency shifts. There are infinite combinations of mass and position which can cause the same shift of one resonant frequency. Finding the mass and position of an adsorbate from the experimentally measured resonant frequencies forms an inverse problem. This study presents a straightforward method to determine the adsorbate mass and position by using the changes of two resonant frequencies. Because detecting the position of an adsorbate can be extremely difficult, especially when the adsorbate is as small as an atom or a molecule, this new inverse problem-solving method should be of some help to the mass resonator sensor application of detecting a single adsorbate. How to apply this method to the case of multiple adsorbates is also discussed. PMID:25294971

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

    PubMed

    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

  15. Poly(ionic liquid) immobilized magnetic nanoparticles as new adsorbent for extraction and enrichment of organophosphorus pesticides from tea drinks.

    PubMed

    Zheng, Xiaoyan; He, Lijun; Duan, Yajing; Jiang, Xiuming; Xiang, Guoqiang; Zhao, Wenjie; Zhang, Shusheng

    2014-09-01

    New poly(ionic liquid) immobilized magnetic nanoparticles (PIL-MNPs) were synthesized via co-polymerization of 1-vinyl-3-hexylimidazolium-based ionic liquid and vinyl-modified magnetic particles and were characterized by Fourier transform infrared spectroscopy, X-ray diffraction, transmission electron microscopy, and magnetic measurements. The PIL-MNPs were utilized as adsorbent phases in magnetic solid-phase extraction (MSPE). The extraction and enrichment efficiency were evaluated by using four organophosphorus pesticides (parathion, fenthion, phoxim and temephos) as test analytes. Various parameters, such as amount of adsorbent, adsorption time, desorption solvent and time, and ionic strength were investigated. The proposed method showed good linearity for the analytes in the concentration range of 1-200μgL(-1) with a correlation coefficient (R)>0.9963. Low limit of detection of 0.01μgL(-1) and high enrichment factors ranging from 84 to 161 were achieved. The proposed method has been successfully used to determine organophosphorus pesticides from three tea drink samples with satisfactory recovery of 81.4-112.6% and RSDs of 4.5-11.3%. The PIL-MNP adsorbent can be reused for 20 times without a noticeable decrease in extraction efficiency.

  16. Microwave-assisted activated carbon from cocoa shell as adsorbent for removal of sodium diclofenac and nimesulide from aqueous effluents.

    PubMed

    Saucier, Caroline; Adebayo, Matthew A; Lima, Eder C; Cataluña, Renato; Thue, Pascal S; Prola, Lizie D T; Puchana-Rosero, M J; Machado, Fernando M; Pavan, Flavio A; Dotto, G L

    2015-05-30

    Microwave-induced chemical activation process was used to prepare an activated carbon from cocoa shell for efficient removal of two anti-inflammatories, sodium diclofenac (DFC) and nimesulide (NM), from aqueous solutions. A paste was obtained from a mixture of cocoa shell and inorganic components; with a ratio of inorganic: organic of 1 (CSC-1.0). The mixture was pyrolyzed in a microwave oven in less than 10 min. The CSC-1.0 was acidified with a 6 mol L(-1) HCl under reflux to produce MWCS-1.0. The CSC-1.0 and MWCS-1.0 were characterized using FTIR, SEM, N2 adsorption/desorption curves, X-ray diffraction, and point of zero charge (pHpzc). Experimental variables such as initial pH of the adsorbate solutions and contact time were optimized for adsorptive characteristics of MWCS-1.0. The optimum pH for removal of anti-inflammatories ranged between 7.0 and 8.0. The kinetic of adsorption was investigated using general order, pseudo first-order and pseu do-second order kinetic models. The maximum amounts of DCF and NM adsorbed onto MWCS-1.0 at 25 °C are 63.47 and 74.81 mg g(-1), respectively. The adsorbent was tested on two simulated hospital effluents. MWCS-1.0 is capable of efficient removal of DCF and NM from a medium that contains high sugar and salt concentrations.

  17. Photoelectric response of purple membrane fragments adsorbed on a lipid monolayer supported by mercury and characterization of the resulting interphase.

    PubMed

    Dolfi, Andrea; Aloisi, Giovanni; Guidelli, Rolando

    2002-09-01

    Purple membrane (PM) fragments were adsorbed on a dioleoylphosphatidylcholine (DOPC) monolayer supported by mercury to investigate the kinetics of light-driven proton transport by bacteriorhodopsin (bR). PM fragments were also adsorbed on a mercury-supported triethyleneoxythiol (TET) monolayer. On both monolayers, the light-on current exhibits a finite, potential dependent stationary component that decreases linearly with a positive shift in the applied potential. The light-on and light-off capacitive photocurrents were interpreted on the basis of a simple equivalent circuit, which accounts for the potential dependence of the stationary light-on current. The potential of zero stationary current is about equal to +0.010 V vs. saturated calomel electrode (SCE) on DOPC-coated mercury. The absolute potential difference across the PM fragments adsorbed at this applied potential was estimated on the basis of extrathermodynamic considerations and amounts to about +260 mV; it compares favorably with the value, +250 mV, of the transmembrane potential of zero stationary current across an oocyte plasma membrane incorporating bR [Biophys. J. 74 (1998) 403.]. The effect of the proton pumping activity of photoexcited PM fragments on the electroreduction kinetics of ubiquinone-10 incorporated in the DOPC monolayer underlying the PM fragments was investigated.

  18. Silver and zinc oxide nanostructures loaded on activated carbon as new adsorbents for removal of methylene green: a comparative study.

    PubMed

    Ghaedi, M; Karimi, H; Yousefi, F

    2014-09-01

    In this study, the removal of methylene green (MG) from aqueous solution based on two new adsorbents including silver nanoparticles and zinc oxide nanorods loaded on activated carbon (Ag-NP-AC and ZnO-NR-AC, respectively) has been carried out. The dependency of removal process to variables such as contact time, pH, amount of adsorbents, and initial MG concentration were examined and optimized. It was found that the maximum MG removal percentage was achieved at pH = 7.0 following stirring at 400 r min(-1) for 7 and 6 min for Ag-NP-AC and ZnO-NR-AC, respectively. Equilibrium data were well fitted with the Langmuir model having maximum adsorption capacity of 166.7 and 200 mg g(-1) for Ag-NP-AC and ZnO-NR-AC, respectively. Thermodynamic parameters of MG adsorption on Ag-NP-AC such as enthalpy and entropy changes, activation energy, sticking probability, and Gibbs free energy changes show the spontaneous and endothermic nature of the removal process. Among different conventional kinetic models, the pseudo second-order kinetics in addition to particle diffusion mechanism is the best and efficient model for the prediction and explanation of experimental data of MG adsorption onto both adsorbents.

  19. Decomposition of NO over [Co]-ZSM-5 zeolite: Effect of co-adsorbed O{sub 2}

    SciTech Connect

    Chang, Y.; McCarty, J.G.

    1998-09-10

    The decomposition of NO over four Co-containing ZSM-5 zeolites and Pr, Ga-, and Cu-exchanged ZSM-5 zeolites was investigated using the isotope labeled {sup 15}N{sup 18}O and a temperature-programmed desorption (TPD) technique. The authors found that [Co]-ZSM-5 that contains Co in the framework had the highest activity for NO decomposition, almost an order of magnitude greater than that previously reported for a zeolite catalyst, namely Cu-ZSM-5 obtained under steady-state conditions. The phenomenally high activity of [Co]-ZSM-5 is due to the unique incorporation of Co{sup 2+} in the siliceous MFI structure. For all the catalysts investigated, co-adsorption of NO and O{sub 2} led to a substantial increase in the amount of NO{sub x} adsorbed. However, the adsorbed species were not necessarily NO{sub 2} as reported by others. The authors believe that the interaction between adsorbed NO{sub x} species and O{sub 2} is responsible for enhancing the rate of NO{sub x} decomposition. It is obvious that the framework Co{sup 2+} behaves very differently from Co{sup 2+} in the countercation position and from extra-framework CoO such as that supported on or dispersed on the surface of silicalite also having the same MFI structure.

  20. Molecular adsorbent recirculating system as artificial support therapy for liver failure: a meta-analysis.

    PubMed

    Vaid, Arjun; Chweich, Haval; Balk, Ethan M; Jaber, Bertrand L

    2012-01-01

    Molecular Adsorbent Recirculating System (MARS) is an artificial liver support system that has been developed for patients with liver failure until the liver regains function or as a bridge to transplantation. We conducted a meta-analysis to examine the efficacy of this promising therapy. We searched MEDLINE, EMBASE, and the Cochrane Registry of Controlled Trials databases, and abstracts from the proceedings of several scientific meetings. Patients with acute, acute on chronic, and hyperacute liver failure were included and we compared MARS with standard medical therapy. Randomized and nonrandomized controlled trials were included and Molecular Adsorbent Recirculating System was the intervention used. We evaluated net change in total bilirubin levels, improvement in hepatic encephalopathy and mortality. Nine randomized controlled trials and one nonrandomized controlled study met criteria and were included. By meta-analysis, MARS resulted in a significant decrease in total bilirubin levels (net change -7.0 mg/dl; 95% CI -10.4, -3.7; p < 0.001) and in an improvement in the West-Haven grade of hepatic encephalopathy (odds ratio [OR] 3.0; 95% CI 1.9, 5.0; p < 0.001). There was no beneficial effect on mortality (OR 0.91; 95% CI 0.64, 1.31; p = 0.62). The limitations of this study include a small sample size, an inability to blind with significant heterogeneity among studies, and variable definitions of liver failure. The Molecular Adsorbent Recirculating System is associated with a significant improvement in total bilirubin levels and hepatic encephalopathy but has no impact on survival. Large studies are required to assess the merit of this promising therapy on patient-centered outcomes. PMID:22210651