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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

    2014-02-07

    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. Copyright © 2013 Elsevier B.V. All rights reserved.

  2. Relationship between the Amount of Bitter Substances Adsorbed onto Lipid/Polymer Membrane and the Electric Response of Taste Sensors

    PubMed Central

    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

  3. 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

  4. 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

  5. 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.

  6. 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.

  7. 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

  8. Elephant’s breast milk contains large amounts of glucosamine

    PubMed Central

    TAKATSU, Zenta; TSUDA, Muneya; YAMADA, Akio; MATSUMOTO, Hiroshi; TAKAI, Akira; TAKEDA, Yasuhiro; TAKASE, Mitsunori

    2016-01-01

    Hand-reared elephant calves that are nursed with milk substitutes sometimes suffer bone fractures, probably due to problems associated with nutrition, exercise, sunshine levels and/or genetic factors. As we were expecting the birth of an Asian elephant (Elephas maximus), we analyzed elephant’s breast milk to improve the milk substitutes for elephant calves. Although there were few nutritional differences between conventional substitutes and elephant’s breast milk, we found a large unknown peak in the breast milk during high-performance liquid chromatography-based amino acid analysis and determined that it was glucosamine (GlcN) using liquid chromatography/mass spectrometry. We detected the following GlcN concentrations [mean ± SD] (mg/100 g) in milk hydrolysates produced by treating samples with 6M HCl for 24 hr at 110°C: four elephant’s breast milk samples: 516 ± 42, three cow’s milk mixtures: 4.0 ± 2.2, three mare’s milk samples: 12 ± 1.2 and two human milk samples: 38. The GlcN content of the elephant’s milk was 128, 43 and 14 times greater than those of the cow’s, mare’s and human milk, respectively. Then, we examined the degradation of GlcN during 0–24 hr hydrolyzation with HCl. We estimated that elephant’s milk contains >880 mg/100 g GlcN, which is similar to the levels of major amino acids in elephant’s milk. We concluded that a novel GlcN-containing milk substitute should be developed for elephant calves. The efficacy of GlcN supplements is disputed, and free GlcN is rare in bodily fluids; thus, the optimal molecular form of GlcN requires a further study. PMID:28049867

  9. Plasma protein adsorption to zwitterionic poly (carboxybetaine methacrylate) modified surfaces: chain chemistry and end-group effects on protein adsorption kinetics, adsorbed amounts and immunoblots.

    PubMed

    Abraham, Sinoj; Bahniuk, Markian S; Unsworth, Larry D

    2012-12-01

    Protein-surface interactions are crucial to the overall biocompatability of biomaterials, and are thought to be the impetus towards the adverse host responses such as blood coagulation and complement activation. Only a few studies hint at the ultra-low fouling potential of zwitterionic poly(carboxybetaine methacrylate) (PCBMA) grafted surfaces and, of those, very few systematically investigate their non-fouling behavior. In this work, single protein adsorption studies as well as protein adsorption from complex solutions (i.e. human plasma) were used to evaluate the non-fouling potential of PCBMA grafted silica wafers prepared by nitroxide-mediated free radical polymerization. PCBMAs used for surface grafting varied in charge separating spacer groups that influence the overall surface charges, and chain end-groups that influence the overall hydrophilicity, thereby, allows a better understanding of these effects towards the protein adsorption for these materials. In situ ellipsometry was used to quantify the adsorbed layer thickness and adsorption kinetics for the adsorption of four proteins from single protein buffer solutions, viz, lysozyme, α-lactalbumin, human serum albumin and fibrinogen. Total amount of protein adsorbed on surfaces differed as a function of surface properties and protein characteristics. Finally, immunoblots results showed that human plasma protein adsorption to these surfaces resulted, primarily, in the adsorption of human serum albumin, with total protein adsorbed amounts being the lowest for PCBMA-3 (TEMPO). It was apparent that surface charge and chain hydrophilicity directly influenced protein adsorption behavior of PCBMA systems and are promising materials for biomedical applications.

  10. 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.

  11. Large-Scale Membrane- and Lignin-Modified Adsorbent-Assisted Extraction and Preconcentration of Triazine Analogs and Aflatoxins

    PubMed Central

    Hu, Shun-Wei; Chen, Shushi

    2017-01-01

    The large-scale simultaneous extraction and concentration of aqueous solutions of triazine analogs, and aflatoxins, through a hydrocarbon-based membrane (e.g., polyethylene, polyethylene/polypropylene copolymer) under ambient temperature and atmospheric pressure is reported. The subsequent adsorption of analyte in the extraction chamber over the lignin-modified silica gel facilitates the process by reducing the operating time. The maximum adsorption capacity values for triazine analogs and aflatoxins are mainly adsorption mechanism-dependent and were calculated to be 0.432 and 0.297 mg/10 mg, respectively. The permeation, and therefore the percentage of analyte extracted, ranges from 1% to almost 100%, and varies among the solvents examined. It is considered to be vapor pressure- and chemical polarity-dependent, and is thus highly affected by the nature and thickness of the membrane, the discrepancy in the solubility values of the analyte between the two liquid phases, and the amount of adsorbent used in the process. A dependence on the size of the analyte was observed in the adsorption capacity measurement, but not in the extraction process. The theoretical interaction simulation and FTIR data show that the planar aflatoxin molecule releases much more energy when facing toward the membrane molecule when approaching it, and the mechanism leading to the adsorption. PMID:28398252

  12. Large-Scale Membrane- and Lignin-Modified Adsorbent-Assisted Extraction and Preconcentration of Triazine Analogs and Aflatoxins.

    PubMed

    Hu, Shun-Wei; Chen, Shushi

    2017-04-11

    The large-scale simultaneous extraction and concentration of aqueous solutions of triazine analogs, and aflatoxins, through a hydrocarbon-based membrane (e.g., polyethylene, polyethylene/polypropylene copolymer) under ambient temperature and atmospheric pressure is reported. The subsequent adsorption of analyte in the extraction chamber over the lignin-modified silica gel facilitates the process by reducing the operating time. The maximum adsorption capacity values for triazine analogs and aflatoxins are mainly adsorption mechanism-dependent and were calculated to be 0.432 and 0.297 mg/10 mg, respectively. The permeation, and therefore the percentage of analyte extracted, ranges from 1% to almost 100%, and varies among the solvents examined. It is considered to be vapor pressure- and chemical polarity-dependent, and is thus highly affected by the nature and thickness of the membrane, the discrepancy in the solubility values of the analyte between the two liquid phases, and the amount of adsorbent used in the process. A dependence on the size of the analyte was observed in the adsorption capacity measurement, but not in the extraction process. The theoretical interaction simulation and FTIR data show that the planar aflatoxin molecule releases much more energy when facing toward the membrane molecule when approaching it, and the mechanism leading to the adsorption.

  13. 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.

  14. A MODIFIED METHOD OF OBTAINING LARGE AMOUNTS OF RICKETTSIA PROWAZEKI BY ROENTGEN IRRADIATION OF RATS

    PubMed Central

    Macchiavello, Atilio; Dresser, Richard

    1935-01-01

    The radiation method described by Zinsser and Castaneda for obtaining large amounts of Rickettsia has been carried out successfully with an ordinary radiographic machine. This allows the extension of the method to those communities which do not possess a high voltage Roentgen therapy unit as originally employed. PMID:19870416

  15. Consumption with Large Sip Sizes Increases Food Intake and Leads to Underestimation of the Amount Consumed

    PubMed Central

    Bolhuis, Dieuwerke P.; Lakemond, Catriona M. M.; de Wijk, Rene A.; Luning, Pieternel A.; de Graaf, Cees

    2013-01-01

    Background A number of studies have shown that bite and sip sizes influence the amount of food intake. Consuming with small sips instead of large sips means relatively more sips for the same amount of food to be consumed; people may believe that intake is higher which leads to faster satiation. This effect may be disturbed when people are distracted. Objective The objective of the study is to assess the effects of sip size in a focused state and a distracted state on ad libitum intake and on the estimated amount consumed. Design In this 3×2 cross-over design, 53 healthy subjects consumed ad libitum soup with small sips (5 g, 60 g/min), large sips (15 g, 60 g/min), and free sips (where sip size was determined by subjects themselves), in both a distracted and focused state. Sips were administered via a pump. There were no visual cues toward consumption. Subjects then estimated how much they had consumed by filling soup in soup bowls. Results Intake in the small-sip condition was ∼30% lower than in both the large-sip and free-sip conditions (P<0.001). In addition, subjects underestimated how much they had consumed in the large-sip and free-sip conditions (P<0.03). Distraction led to a general increase in food intake (P = 0.003), independent of sip size. Distraction did not influence sip size or estimations. Conclusions Consumption with large sips led to higher food intake, as expected. Large sips, that were either fixed or chosen by subjects themselves led to underestimations of the amount consumed. This may be a risk factor for over-consumption. Reducing sip or bite sizes may successfully lower food intake, even in a distracted state. PMID:23372657

  16. Detection of tiny amounts of fissile materials in large-sized containers with radioactive waste

    NASA Astrophysics Data System (ADS)

    Batyaev, V. F.; Skliarov, S. V.

    2018-01-01

    The paper is devoted to non-destructive control of tiny amounts of fissile materials in large-sized containers filled with radioactive waste (RAW). The aim of this work is to model an active neutron interrogation facility for detection of fissile ma-terials inside NZK type containers with RAW and determine the minimal detectable mass of U-235 as a function of various param-eters: matrix type, nonuniformity of container filling, neutron gen-erator parameters (flux, pulse frequency, pulse duration), meas-urement time. As a result the dependence of minimal detectable mass on fissile materials location inside container is shown. Nonu-niformity of the thermal neutron flux inside a container is the main reason of the space-heterogeneity of minimal detectable mass in-side a large-sized container. Our experiments with tiny amounts of uranium-235 (<1 g) confirm the detection of fissile materials in NZK containers by using active neutron interrogation technique.

  17. 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

  18. Presentation of a large amount of moving objects in a virtual environment

    NASA Astrophysics Data System (ADS)

    Ye, Huanzhuo; Gong, Jianya; Ye, Jing

    2004-05-01

    It needs a lot of consideration to manage the presentation of a large amount of moving objects in virtual environment. Motion state model (MSM) is used to represent the motion of objects and 2n tree is used to index the motion data stored in database or files. To minimize the necessary memory occupation for static models, cache with LRU or FIFO refreshing is introduced. DCT and wavelet work well with different playback speeds of motion presentation because they can filter low frequencies from motion data and adjust the filter according to playback speed. Since large amount of data are continuously retrieved, calculated, used for displaying, and then discarded, multithreading technology is naturally employed though single thread with carefully arranged data retrieval also works well when the number of objects is not very big. With multithreading, the level of concurrence should be placed at data retrieval, where waiting may occur, rather than at calculating or displaying, and synchronization should be carefully arranged to make sure that different threads can collaborate well. Collision detection is not needed when playing with history data and sampled current data; however, it is necessary for spatial state prediction. When the current state is presented, either predicting-adjusting method or late updating method could be used according to the users' preference.

  19. 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.

  20. 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.

  1. Semantic interoperability challenges to process large amount of data perspectives in forensic and legal medicine.

    PubMed

    Jaulent, Marie-Christine; Leprovost, Damien; Charlet, Jean; Choquet, Remy

    2018-07-01

    This article is a position paper dealing with semantic interoperability challenges. It addresses the Variety and Veracity dimensions when integrating, sharing and reusing large amount of heterogeneous data for data analysis and decision making applications in the healthcare domain. Many issues are raised by the necessity to conform Big Data to interoperability standards. We discuss how semantics can contribute to the improvement of information sharing and address the problem of data mediation with domain ontologies. We then introduce the main steps for building domain ontologies as they could be implemented in the context of Forensic and Legal medicine. We conclude with a particular emphasis on the current limitations in standardisation and the importance of knowledge formalization. Copyright © 2016 Elsevier Ltd and Faculty of Forensic and Legal Medicine. All rights reserved.

  2. 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

  3. Generation Expansion Planning With Large Amounts of Wind Power via Decision-Dependent Stochastic Programming

    SciTech Connect

    Zhan, Yiduo; Zheng, Qipeng P.; Wang, Jianhui

    Power generation expansion planning needs to deal with future uncertainties carefully, given that the invested generation assets will be in operation for a long time. Many stochastic programming models have been proposed to tackle this challenge. However, most previous works assume predetermined future uncertainties (i.e., fixed random outcomes with given probabilities). In several recent studies of generation assets' planning (e.g., thermal versus renewable), new findings show that the investment decisions could affect the future uncertainties as well. To this end, this paper proposes a multistage decision-dependent stochastic optimization model for long-term large-scale generation expansion planning, where large amounts of windmore » power are involved. In the decision-dependent model, the future uncertainties are not only affecting but also affected by the current decisions. In particular, the probability distribution function is determined by not only input parameters but also decision variables. To deal with the nonlinear constraints in our model, a quasi-exact solution approach is then introduced to reformulate the multistage stochastic investment model to a mixed-integer linear programming model. The wind penetration, investment decisions, and the optimality of the decision-dependent model are evaluated in a series of multistage case studies. The results show that the proposed decision-dependent model provides effective optimization solutions for long-term generation expansion planning.« less

  4. Evaluation of Flush-Mounted, S-Duct Inlets with Large Amounts of Boundary Layer Ingestion

    NASA Technical Reports Server (NTRS)

    Berrier, Bobby L.; Morehouse, Melissa B.

    2003-01-01

    A new high Reynolds number test capability for boundary layer ingesting inlets has been developed for the NASA Langley Research Center 0.3-Meter Transonic Cryogenic Tunnel. Using this new capability, an experimental investigation of four S-duct inlet configurations with large amounts of boundary layer ingestion (nominal boundary layer thickness of about 40% of inlet height) was conducted at realistic operating conditions (high subsonic Mach numbers and full-scale Reynolds numbers). The objectives of this investigation were to 1) provide a database for CFD tool validation on boundary layer ingesting inlets operating at realistic conditions and 2) provide a baseline inlet for future inlet flow-control studies. Tests were conducted at Mach numbers from 0.25 to 0.83, Reynolds numbers (based on duct exit diameter) from 5.1 million to a full-scale value of 13.9 million, and inlet mass-flow ratios from 0.39 to 1.58 depending on Mach number. Results of this investigation indicate that inlet pressure recovery generally decreased and inlet distortion generally increased with increasing Mach number. Except at low Mach numbers, increasing inlet mass-flow increased pressure recovery and increased distortion. Increasing the amount of boundary layer ingestion (by decreasing inlet throat height) or ingesting a boundary layer with a distorted (adverse) profile decreased pressure recovery and increased distortion. Finally, increasing Reynolds number had almost no effect on inlet distortion but increased inlet recovery by about one-half percent at a Mach number near cruise.

  5. Evaluation of Flush-Mounted, S-Duct Inlets With Large Amounts of Boundary Layer Ingestion

    NASA Technical Reports Server (NTRS)

    Berrier, Bobby L.; Morehouse, Melissa B.

    2003-01-01

    A new high Reynolds number test capability for boundary layer ingesting inlets has been developed for the NASA Langley Research Center 0.3-Meter Transonic Cryogenic Tunnel. Using this new capability, an experimental investigation of four S-duct inlet configurations with large amounts of boundary layer ingestion (nominal boundary layer thickness of about 40% of inlet height) was conducted at realistic operating conditions (high subsonic Mach numbers and full-scale Reynolds numbers). The objectives of this investigation were to 1) develop a new high Reynolds number, boundary-layer ingesting inlet test capability, 2) evaluate the performance of several boundary layer ingesting S-duct inlets, 3) provide a database for CFD tool validation, and 4) provide a baseline inlet for future inlet flow-control studies. Tests were conducted at Mach numbers from 0.25 to 0.83, Reynolds numbers (based on duct exit diameter) from 5.1 million to a fullscale value of 13.9 million, and inlet mass-flow ratios from 0.39 to 1.58 depending on Mach number. Results of this investigation indicate that inlet pressure recovery generally decreased and inlet distortion generally increased with increasing Mach number. Except at low Mach numbers, increasing inlet mass-flow increased pressure recovery and increased distortion. Increasing the amount of boundary layer ingestion (by decreasing inlet throat height and increasing inlet throat width) or ingesting a boundary layer with a distorted profile decreased pressure recovery and increased distortion. Finally, increasing Reynolds number had almost no effect on inlet distortion but increased inlet recovery by about one-half percent at a Mach number near cruise.

  6. 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

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

    SciTech Connect

    Hinkleman, Travis M.

    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 habitatmore » 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

  8. 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.

  9. Dodecylbenzene sulfonate-coated magnetite nanoparticles as a new adsorbent for solid phase extraction-spectrophotometric determination of ultra trace amounts of ammonium in water samples.

    PubMed

    Eskandari, Habibollah; Shariati, Mohammad Reza

    2011-10-17

    A new method was proposed for the determination of ammonium based on the preconcentration with dodecylbenzene sulfonate modified magnetite nanoparticles. Ammonium was oxidized to nitrite by hypobromite and then the nitrite produced was determined spectrophotometrically, using sulfabenzamide and N-(1-naphthyl) ethylenediamine after solid phase extraction. The azo dye produced was desorbed by an appropriate small volume of sodium hydroxide prior to the absorbance measurement. The linear calibration graphs were obtained in the concentration range of 0.03-6.00 ng mL(-1) ammonium. The relative standard deviation and recovery percents were 1.0 and 99.0, respectively, for 1.0 ng mL(-1) ammonium, and the limit of detection was 3.2 ng L(-1) ammonium. The interfering effects of a large number of diverse ions on the determination of ammonium were studied. The method was applied to the determination of ammonium in various types of water resources. The results revealed a high efficiency for the recommended ammonium determination method. Copyright © 2011 Elsevier B.V. All rights reserved.

  10. A method to study response of large trees to different amounts of available soil water

    Treesearch

    D.H. Marx; Shi-Jean S. Sung; J.S. Cunningham; M.D. Thompson; L.M. White

    1995-01-01

    A method was developed to manipulate available soil water on large trees by intercepting thrufall with gutters placed under tree canopies and irrigating the intercepted thrufall onto other trees. With this design, trees were exposed for 2 years to either 25% less thrufall, normal thrufall, or 25% additional thrufall.Undercanopy construction in these plots moderately...

  11. A Method to Study Response of Large Trees to Different Amounts of Available Soil Water

    Treesearch

    Donald H. Marx; Shi-jean S. Sung; James S. Cunningham; Michael D. Thompson; Linda M. White

    1995-01-01

    A method was developed to manipulate available soil water on large trees by intercepting thrufall with gutters placed under tree canopies and irrigating the intercepted thrufall onto other trees. With this design, trees were exposed for 2 years to either 25 percent less thrufall, normal tbrufall,or 25 percent additional thrufall. Undercanopy construction in these plots...

  12. Boreal Forests Sequester Large Amounts of Mercury over Millennial Time Scales in the Absence of Wildfire.

    PubMed

    Giesler, Reiner; Clemmensen, Karina E; Wardle, David A; Klaminder, Jonatan; Bindler, Richard

    2017-03-07

    Alterations in fire activity due to climate change and fire suppression may have profound effects on the balance between storage and release of carbon (C) and associated volatile elements. Stored soil mercury (Hg) is known to volatilize due to wildfires and this could substantially affect the land-air exchange of Hg; conversely the absence of fires and human disturbance may increase the time period over which Hg is sequestered. Here we show for a wildfire chronosequence spanning over more than 5000 years in boreal forest in northern Sweden that belowground inventories of total Hg are strongly related to soil humus C accumulation (R 2 = 0.94, p < 0.001). Our data clearly show that northern boreal forest soils have a strong sink capacity for Hg, and indicate that the sequestered Hg is bound in soil organic matter pools accumulating over millennia. Our results also suggest that more than half of the Hg stock in the sites with the longest time since fire originates from deposition predating the onset of large-scale anthropogenic emissions. This study emphasizes the importance of boreal forest humus soils for Hg storage and reveals that this pool is likely to persist over millennial time scales in the prolonged absence of fire.

  13. A MBD-seq protocol for large-scale methylome-wide studies with (very) low amounts of DNA.

    PubMed

    Aberg, Karolina A; Chan, Robin F; Shabalin, Andrey A; Zhao, Min; Turecki, Gustavo; Staunstrup, Nicklas Heine; Starnawska, Anna; Mors, Ole; Xie, Lin Y; van den Oord, Edwin Jcg

    2017-09-01

    We recently showed that, after optimization, our methyl-CpG binding domain sequencing (MBD-seq) application approximates the methylome-wide coverage obtained with whole-genome bisulfite sequencing (WGB-seq), but at a cost that enables adequately powered large-scale association studies. A prior drawback of MBD-seq is the relatively large amount of genomic DNA (ideally >1 µg) required to obtain high-quality data. Biomaterials are typically expensive to collect, provide a finite amount of DNA, and may simply not yield sufficient starting material. The ability to use low amounts of DNA will increase the breadth and number of studies that can be conducted. Therefore, we further optimized the enrichment step. With this low starting material protocol, MBD-seq performed equally well, or better, than the protocol requiring ample starting material (>1 µg). Using only 15 ng of DNA as input, there is minimal loss in data quality, achieving 93% of the coverage of WGB-seq (with standard amounts of input DNA) at similar false/positive rates. Furthermore, across a large number of genomic features, the MBD-seq methylation profiles closely tracked those observed for WGB-seq with even slightly larger effect sizes. This suggests that MBD-seq provides similar information about the methylome and classifies methylation status somewhat more accurately. Performance decreases with <15 ng DNA as starting material but, even with as little as 5 ng, MBD-seq still achieves 90% of the coverage of WGB-seq with comparable genome-wide methylation profiles. Thus, the proposed protocol is an attractive option for adequately powered and cost-effective methylome-wide investigations using (very) low amounts of DNA.

  14. Amounts and activity concentrations of radioactive wastes from the cleanup of large areas contaminated in nuclear accidents

    SciTech Connect

    Lehto, J.; Ikaeheimonen, T.K.; Salbu, B.

    The fallout from a major nuclear accident at a nuclear plant may result in a wide-scale contamination of the environment. Cleanup of contaminated areas is of special importance if these areas are populated or cultivated. All cleanup measures generate high amounts of radioactive waste, which have to be treated and disposed of in a safe manner. Scenarios assessing the amounts and activity concentrations of radioactive wastes for various cleanup measures after severe nuclear accidents have been worked out for urban, forest and agricultural areas. These scenarios are based on contamination levels and ares of contaminated lands from a model accident,more » which simulates a worst case accident at a nuclear power plant. Amounts and activity concentrations of cleanup wastes are not only dependent on the contamination levels and areas of affected lands, but also on the type of deposition, wet or dry, on the time between the deposition and the cleanup work, on the season, at which the deposition took place, and finally on the level of cleanup work. In this study practically all types of cleanup wastes were considered, whether or not the corresponding cleanup measures are cost-effective or justified. All cleanup measures are shown to create large amounts of radioactive wastes, but the amounts, as well as the activity concentrations vary widely from case to case.« less

  15. Cutting Edge: Protection by Antiviral Memory CD8 T Cells Requires Rapidly Produced Antigen in Large Amounts.

    PubMed

    Remakus, Sanda; Ma, Xueying; Tang, Lingjuan; Xu, Ren-Huan; Knudson, Cory; Melo-Silva, Carolina R; Rubio, Daniel; Kuo, Yin-Ming; Andrews, Andrew; Sigal, Luis J

    2018-05-15

    Numerous attempts to produce antiviral vaccines by harnessing memory CD8 T cells have failed. A barrier to progress is that we do not know what makes an Ag a viable target of protective CD8 T cell memory. We found that in mice susceptible to lethal mousepox (the mouse homolog of human smallpox), a dendritic cell vaccine that induced memory CD8 T cells fully protected mice when the infecting virus produced Ag in large quantities and with rapid kinetics. Protection did not occur when the Ag was produced in low amounts, even with rapid kinetics, and protection was only partial when the Ag was produced in large quantities but with slow kinetics. Hence, the amount and timing of Ag expression appear to be key determinants of memory CD8 T cell antiviral protective immunity. These findings may have important implications for vaccine design. Copyright © 2018 by The American Association of Immunologists, Inc.

  16. Highly Sensitive GMO Detection Using Real-Time PCR with a Large Amount of DNA Template: Single-Laboratory Validation.

    PubMed

    Mano, Junichi; Hatano, Shuko; Nagatomi, Yasuaki; Futo, Satoshi; Takabatake, Reona; Kitta, Kazumi

    2018-03-01

    Current genetically modified organism (GMO) detection methods allow for sensitive detection. However, a further increase in sensitivity will enable more efficient testing for large grain samples and reliable testing for processed foods. In this study, we investigated real-time PCR-based GMO detection methods using a large amount of DNA template. We selected target sequences that are commonly introduced into many kinds of GM crops, i.e., 35S promoter and nopaline synthase (NOS) terminator. This makes the newly developed method applicable to a wide range of GMOs, including some unauthorized ones. The estimated LOD of the new method was 0.005% of GM maize events; to the best of our knowledge, this method is the most sensitive among the GM maize detection methods for which the LOD was evaluated in terms of GMO content. A 10-fold increase in the DNA amount as compared with the amount used under common testing conditions gave an approximately 10-fold reduction in the LOD without PCR inhibition. Our method is applicable to various analytical samples, including processed foods. The use of other primers and fluorescence probes would permit highly sensitive detection of various recombinant DNA sequences besides the 35S promoter and NOS terminator.

  17. Antibody recognition of the glycoprotein g of viral haemorrhagic septicemia virus (VHSV) purified in large amounts from insect larvae.

    PubMed

    Encinas, Paloma; Gomez-Sebastian, Silvia; Nunez, Maria Carmen; Gomez-Casado, Eduardo; Escribano, Jose M; Estepa, Amparo; Coll, Julio

    2011-06-21

    There are currently no purification methods capable of producing the large amounts of fish rhabdoviral glycoprotein G (gpG) required for diagnosis and immunisation purposes or for studying structure and molecular mechanisms of action of this molecule (ie. pH-dependent membrane fusion). As a result of the unavailability of large amounts of the gpG from viral haemorrhagic septicaemia rhabdovirus (VHSV), one of the most dangerous viruses affecting cultured salmonid species, research interests in this field are severely hampered. Previous purification methods to obtain recombinant gpG from VHSV in E. coli, yeast and baculovirus grown in insect cells have not produced soluble conformations or acceptable yields. The development of large-scale purification methods for gpGs will also further research into other fish rhabdoviruses, such as infectious haematopoietic necrosis virus (IHNV), spring carp viremia virus (SVCV), hirame rhabdovirus (HIRRV) and snakehead rhabdovirus (SHRV). Here we designed a method to produce milligram amounts of soluble VHSV gpG. Only the transmembrane and carboxy terminal-deleted (amino acid 21 to 465) gpG was efficiently expressed in insect larvae. Recognition of G21-465 by ß-mercaptoethanol-dependent neutralizing monoclonal antibodies (N-MAbs) and pH-dependent recognition by sera from VHSV-hyperimmunized or VHSV-infected rainbow trout (Oncorhynchus mykiss) was demonstrated. Given that the purified G21-465 conserved some of its most important properties, this method might be suitable for the large-scale production of fish rhabdoviral gpGs for use in diagnosis, fusion and antigenicity studies.

  18. Antibody recognition of the glycoprotein g of viral haemorrhagic septicemia virus (VHSV) purified in large amounts from insect larvae

    PubMed Central

    2011-01-01

    Background There are currently no purification methods capable of producing the large amounts of fish rhabdoviral glycoprotein G (gpG) required for diagnosis and immunisation purposes or for studying structure and molecular mechanisms of action of this molecule (ie. pH-dependent membrane fusion). As a result of the unavailability of large amounts of the gpG from viral haemorrhagic septicaemia rhabdovirus (VHSV), one of the most dangerous viruses affecting cultured salmonid species, research interests in this field are severely hampered. Previous purification methods to obtain recombinant gpG from VHSV in E. coli, yeast and baculovirus grown in insect cells have not produced soluble conformations or acceptable yields. The development of large-scale purification methods for gpGs will also further research into other fish rhabdoviruses, such as infectious haematopoietic necrosis virus (IHNV), spring carp viremia virus (SVCV), hirame rhabdovirus (HIRRV) and snakehead rhabdovirus (SHRV). Findings Here we designed a method to produce milligram amounts of soluble VHSV gpG. Only the transmembrane and carboxy terminal-deleted (amino acid 21 to 465) gpG was efficiently expressed in insect larvae. Recognition of G21-465 by ß-mercaptoethanol-dependent neutralizing monoclonal antibodies (N-MAbs) and pH-dependent recognition by sera from VHSV-hyperimmunized or VHSV-infected rainbow trout (Oncorhynchus mykiss) was demonstrated. Conclusions Given that the purified G21-465 conserved some of its most important properties, this method might be suitable for the large-scale production of fish rhabdoviral gpGs for use in diagnosis, fusion and antigenicity studies. PMID:21693048

  19. The Application Law of Large Numbers That Predicts The Amount of Actual Loss in Insurance of Life

    NASA Astrophysics Data System (ADS)

    Tinungki, Georgina Maria

    2018-03-01

    The law of large numbers is a statistical concept that calculates the average number of events or risks in a sample or population to predict something. The larger the population is calculated, the more accurate predictions. In the field of insurance, the Law of Large Numbers is used to predict the risk of loss or claims of some participants so that the premium can be calculated appropriately. For example there is an average that of every 100 insurance participants, there is one participant who filed an accident claim, then the premium of 100 participants should be able to provide Sum Assured to at least 1 accident claim. The larger the insurance participant is calculated, the more precise the prediction of the calendar and the calculation of the premium. Life insurance, as a tool for risk spread, can only work if a life insurance company is able to bear the same risk in large numbers. Here apply what is called the law of large number. The law of large numbers states that if the amount of exposure to losses increases, then the predicted loss will be closer to the actual loss. The use of the law of large numbers allows the number of losses to be predicted better.

  20. 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. Copyright © 2016 Elsevier Ltd. All rights reserved.

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

    PubMed

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

    2017-08-15

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

  2. Treatment of wastewater containing a large amount of suspended solids by a novel multi-staged UASB reactor.

    PubMed

    Uemura, S; Harada, H; Ohashi, A; Torimura, S

    2005-12-01

    Treatment of artificial wastewater containing a large amount of suspended solids comprised of soybean processing waste and pig fodder was studied using a novel multi-staged upflow anaerobic sludge blanket reactor. The reactor consisted of three compartments, each containing a gas solid separator. The wastewater had chemical oxygen demand of approximately 21600 mg l(-1), suspended solids of 12800 mg l(-1), and an ammonia concentration of 945 mg l(-1). A continuous experiment without effluent circulation showed that the multi-staged reactor was not that effective for the treatment of wastewater containing a large amount of suspended solids. However, operation of the reactor with circulation of effluent enabled the reactor to achieve organic removal of 85% and approximately 70% methane conversion at loading rates of between 4.0 to 5.4 kg-chemical oxygen demand per cubic meter per day, meaning that the reactor was more effective when effluent was circulated. Morphological investigation revealed that the crude fiber in the sludge was partially degraded and that it had many small depressions on its surface. Evolved biogas may have become caught in these depressions of the fibers and caused washout of the sludge.

  3. 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.

  4. Enhanced membrane filtration of wood hydrolysates for hemicelluloses recovery by pretreatment with polymeric adsorbents.

    PubMed

    Koivula, Elsi; Kallioinen, Mari; Sainio, Tuomo; Antón, Enrique; Luque, Susana; Mänttäri, Mika

    2013-09-01

    In this study adsorption of foulants from birch and pine/eucalyptus wood hydrolysates on two polymeric adsorbents was studied aiming to reduce the membrane fouling. The effect of the pretreatment of hydrolysate on polyethersulphone membrane performance was studied in dead-end filtration experiments. Adsorption pretreatment improved significantly filtration capacity and decreased membrane fouling. Especially high-molecular weight lignin was efficiently removed. A multistep adsorption pretreatment was found to reduce the amount of adsorbent required. While large adsorbent amount was shown to increase flux in filtration, it was found also to cause significant hemicellulose losses. Copyright © 2013 Elsevier Ltd. All rights reserved.

  5. 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.This CD-ROM supplement contains inlet data including: Boundary layer data, Duct static pressure data, performance-AIP (fan face) data, Photos, Tunnel wall P-PTO data and definitions.

  6. 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.

  7. Methods to isolate a large amount of generative cells, sperm cells and vegetative nuclei from tomato pollen for "omics" analysis.

    PubMed

    Lu, Yunlong; Wei, Liqin; Wang, Tai

    2015-01-01

    The development of sperm cells (SCs) from microspores involves a set of finely regulated molecular and cellular events and the coordination of these events. The mechanisms underlying these events and their interconnections remain a major challenge. Systems analysis of genome-wide molecular networks and functional modules with high-throughput "omics" approaches is crucial for understanding the mechanisms; however, this study is hindered because of the difficulty in isolating a large amount of cells of different types, especially generative cells (GCs), from the pollen. Here, we optimized the conditions of tomato pollen germination and pollen tube growth to allow for long-term growth of pollen tubes in vitro with SCs generated in the tube. Using this culture system, we developed methods for isolating GCs, SCs and vegetative cell nuclei (VN) from just-germinated tomato pollen grains and growing pollen tubes and their purification by Percoll density gradient centrifugation. The purity and viability of isolated GCs and SCs were confirmed by microscopy examination and fluorescein diacetate staining, respectively, and the integrity of VN was confirmed by propidium iodide staining. We could obtain about 1.5 million GCs and 2.0 million SCs each from 180 mg initiated pollen grains, and 10 million VN from 270 mg initiated pollen grains germinated in vitro in each experiment. These methods provide the necessary preconditions for systematic biology studies of SC development and differentiation in higher plants.

  8. 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

  9. Essential strategies to optimize asymmetric PCR conditions as a reliable method to generate large amount of ssDNA aptamers.

    PubMed

    Heiat, Mohammad; Ranjbar, Reza; Latifi, Ali Mohammad; Rasaee, Mohammad Javad; Farnoosh, Gholamreza

    2017-07-01

    Asymmetric PCR, a simple method to generate single-stranded DNA (ssDNA) aptamers in systematic evaluation of ligand by exponential enrichments rounds, is coupled with limitations. We investigated the essential strategies for optimization of conditions to perform a high-quality asymmetric PCR. Final concentrations of primers and template, the number of PCR cycles, and annealing temperature were selected as optimizing variables. The qualities of visualized PCR products were analyzed by ImageJ software. The highest proportion of interested DNA than unwanted products was considered as optimum conditions. Results revealed that the best values for primers ratio, final template concentration, annealing temperature, and PCR cycles were, respectively, 30:1, 1 ng/μL, 55 °C, and 20 cycles for the first and 50:1, 2 ng/μL, 59 °C, and 20 cycles for other rounds. No significant difference was found between optimized asymmetric PCR results in the rounds of two to eight (P > 0.05). The ssDNA quality in round 10 was significantly better than other rounds (P < 0.05). Generally, the ssDNA product with less dimers, double-stranded DNA (dsDNA), and smear are preferable. The dsDNA contamination is the worst, because it can act as antidote and inhibits aptameric performance. Therefore, to choose the best conditions, the lower amount of dsDNA is more important than other unwanted products. © 2016 International Union of Biochemistry and Molecular Biology, Inc.

  10. Increased mortality of respiratory diseases, including lung cancer, in the area with large amount of ashfall from Mount Sakurajima volcano.

    PubMed

    Higuchi, Kenta; Koriyama, Chihaya; Akiba, Suminori

    2012-01-01

    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. 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. 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. 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.

  11. 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". Copyright © 2011. Published by Elsevier Inc.

  12. Delimitation of the Thoracosphaeraceae (Dinophyceae), including the calcareous dinoflagellates, based on large amounts of ribosomal RNA sequence data.

    PubMed

    Gottschling, Marc; Soehner, Sylvia; Zinssmeister, Carmen; John, Uwe; Plötner, Jörg; Schweikert, Michael; Aligizaki, Katerina; Elbrächter, Malte

    2012-01-01

    The phylogenetic relationships of the Dinophyceae (Alveolata) are not sufficiently resolved at present. The Thoracosphaeraceae (Peridiniales) are the only group of the Alveolata that include members with calcareous coccoid stages; this trait is considered apomorphic. Although the coccoid stage apparently is not calcareous, Bysmatrum has been assigned to the Thoracosphaeraceae based on thecal morphology. We tested the monophyly of the Thoracosphaeraceae using large sets of ribosomal RNA sequence data of the Alveolata including the Dinophyceae. Phylogenetic analyses were performed using Maximum Likelihood and Bayesian approaches. The Thoracosphaeraceae were monophyletic, but included also a number of non-calcareous dinophytes (such as Pentapharsodinium and Pfiesteria) and even parasites (such as Duboscquodinium and Tintinnophagus). Bysmatrum had an isolated and uncertain phylogenetic position outside the Thoracosphaeraceae. The phylogenetic relationships among calcareous dinophytes appear complex, and the assumption of the single origin of the potential to produce calcareous structures is challenged. The application of concatenated ribosomal RNA sequence data may prove promising for phylogenetic reconstructions of the Dinophyceae in future. Copyright © 2011 Elsevier GmbH. All rights reserved.

  13. 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.

  14. Old age and underlying interstitial abnormalities are risk factors for development of ARDS after pleurodesis using limited amount of large particle size talc.

    PubMed

    Shinno, Yuki; Kage, Hidenori; Chino, Haruka; Inaba, Atsushi; Arakawa, Sayaka; Noguchi, Satoshi; Amano, Yosuke; Yamauchi, Yasuhiro; Tanaka, Goh; Nagase, Takahide

    2018-01-01

    Talc pleurodesis is commonly performed to manage refractory pleural effusion or pneumothorax. It is considered as a safe procedure as long as a limited amount of large particle size talc is used. However, acute respiratory distress syndrome (ARDS) is a rare but serious complication after talc pleurodesis. We sought to determine the risk factors for the development of ARDS after pleurodesis using a limited amount of large particle size talc. We retrospectively reviewed patients who underwent pleurodesis with talc or OK-432 at the University of Tokyo Hospital. Twenty-seven and 35 patients underwent chemical pleurodesis using large particle size talc (4 g or less) or OK-432, respectively. Four of 27 (15%) patients developed ARDS after talc pleurodesis. Patients who developed ARDS were significantly older than those who did not (median 80 vs 66 years, P = 0.02) and had a higher prevalence of underlying interstitial abnormalities on chest computed tomography (CT; 2/4 vs 1/23, P < 0.05). No patient developed ARDS after pleurodesis with OK-432. This is the first case series of ARDS after pleurodesis using a limited amount of large particle size talc. Older age and underlying interstitial abnormalities on chest CT seem to be risk factors for developing ARDS after talc pleurodesis. © 2017 Asian Pacific Society of Respirology.

  15. An adsorbent with a high adsorption capacity obtained from the cellulose sludge of industrial residues.

    PubMed

    Orlandi, Géssica; Cavasotto, Jéssica; Machado, Francisco R S; Colpani, Gustavo L; Magro, Jacir Dal; Dalcanton, Francieli; Mello, Josiane M M; Fiori, Márcio A

    2017-02-01

    One of the major problems in effluent treatment plants of the cellulose and paper industry is the large amount of residual sludge generated. Therefore, this industry is trying to develop new methods to treat such residues and to use them as new products, such as adsorbents. In this regard, the objective of this work was to develop an adsorbent using the raw activated sludge generated by the cellulose and paper industry. The activated cellulose sludge, after being dried, was chemically activated with 42.5% (v/v) phosphoric acid at 85 °C for 1 h and was charred at 500 °C, 600 °C and 700 °C for 2 h. The efficiency of the obtained adsorbent materials was evaluated using kinetic tests with methylene blue solutions. Using the adsorption kinetics, it was verified that the three adsorbents showed the capacity to adsorb dye, and the adsorbent obtained at a temperature of 600 °C showed the highest adsorption capacity of 107.1 mg g -1 . The kinetic model that best fit the experimental data was pseudo-second order. The Langmuir-Freudlich isotherm adequately described the experimental data. As a result, the cellulose sludge generated by the cellulose and paper industries could be used as an adsorbent. Copyright © 2016 Elsevier Ltd. All rights reserved.

  16. 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

  17. Large Amounts of Reactivated Virus in Tears Precedes Recurrent Herpes Stromal Keratitis in Stressed Rabbits Latently Infected with Herpes Simplex Virus.

    PubMed

    Perng, Guey-Chuen; Osorio, Nelson; Jiang, Xianzhi; Geertsema, Roger; Hsiang, Chinhui; Brown, Don; BenMohamed, Lbachir; Wechsler, Steven L

    2016-01-01

    Recurrent herpetic stromal keratitis (rHSK), due to an immune response to reactivation of herpes simplex virus (HSV-1), can cause corneal blindness. The development of therapeutic interventions such as drugs and vaccines to decrease rHSK have been hampered by the lack of a small and reliable animal model in which rHSK occurs at a high frequency during HSV-1 latency. The aim of this study is to develop a rabbit model of rHSK in which stress from elevated temperatures increases the frequency of HSV-1 reactivations and rHSK. Rabbits latently infected with HSV-1 were subjected to elevated temperatures and the frequency of viral reactivations and rHSK were determined. In an experiment in which rabbits latently infected with HSV-1 were subjected to ill-defined stress as a result of failure of the vivarium air conditioning system, reactivation of HSV-1 occurred at over twice the normal frequency. In addition, 60% of eyes developed severe rHSK compared to <1% of eyes normally. All episodes of rHSK were preceded four to five days prior by an unusually large amount of reactivated virus in the tears of that eye and whenever this unusually large amount of reactivated virus was detected in tears, rHSK always appeared 4-5 days later. In subsequent experiments using well defined heat stress the reactivation frequency was similarly increased, but no eyes developed rHSK. The results reported here support the hypothesis that rHSK is associated not simply with elevated reactivation frequency, but rather with rare episodes of very high levels of reactivated virus in tears 4-5 days earlier.

  18. Large Amounts of Reactivated Virus in Tears Precedes Recurrent Herpes Stromal Keratitis in Stressed Rabbits Latently Infected with Herpes Simplex Virus

    PubMed Central

    Perng, Guey-Chuen; Osorio, Nelson; Jiang, Xianzhi; Geertsema, Roger; Hsiang, Chinhui; Brown, Don; BenMohamed, Lbachir; Wechsler, Steven L.

    2017-01-01

    Aim Recurrent herpetic stromal keratitis (rHSK), due to an immune response to reactivation of herpes simplex virus (HSV-1), can cause corneal blindness. The development of therapeutic interventions such as drugs and vaccines to decrease rHSK have been hampered by the lack of a small and reliable animal model in which rHSK occurs at a high frequency during HSV-1 latency. The aim of this study is to develop a rabbit model of rHSK in which stress from elevated temperatures increases the frequency of HSV-1 reactivations and rHSK. Materials and methods Rabbits latently infected with HSV-1 were subjected to elevated temperatures and the frequency of viral reactivations and rHSK were determined. Results In an experiment in which rabbits latently infected with HSV-1 were subjected to ill-defined stress as a result of failure of the vivarium air conditioning system, reactivation of HSV-1 occurred at over twice the normal frequency. In addition, 60% of eyes developed severe rHSK compared to <1% of eyes normally. All episodes of rHSK were preceded four to five days prior by an unusually large amount of reactivated virus in the tears of that eye and whenever this unusually large amount of reactivated virus was detected in tears, rHSK always appeared 4–5 days later. In subsequent experiments using well defined heat stress the reactivation frequency was similarly increased, but no eyes developed rHSK. Conclusions The results reported here support the hypothesis that rHSK is associated not simply with elevated reactivation frequency, but rather with rare episodes of very high levels of reactivated virus in tears 4–5 days earlier. PMID:25859798

  19. 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.

  20. Accumulation of Polyhydroxyalkanoic Acid Containing Large Amounts of Unsaturated Monomers in Pseudomonas fluorescens BM07 Utilizing Saccharides and Its Inhibition by 2-Bromooctanoic Acid

    PubMed Central

    Lee, Ho-Joo; Choi, Mun Hwan; Kim, Tae-Un; Yoon, Sung Chul

    2001-01-01

    A psychrotrophic bacterium, Pseudomonas fluorescens BM07, which is able to accumulate polyhydroxyalkanoic acid (PHA) containing large amounts of 3-hydroxy-cis-5-dodecenoate unit up to 35 mol% in the cell from unrelated substrates such as fructose, succinate, etc., was isolated from an activated sludge in a municipal wastewater treatment plant. When it was grown on heptanoic acid (C7) to hexadecanoic acid (C16) as the sole carbon source, the monomer compositional characteristics of the synthesized PHA were similar to those observed in other fluorescent pseudomonads belonging to rRNA homology group I. However, growth on stearic acid (C18) led to no PHA accumulation, but instead free stearic acid was stored in the cell. The existence of the linkage between fatty acid de novo synthesis and PHA synthesis was confirmed by using inhibitors such as acrylic acid and two other compounds, 2-bromooctanoic acid and 4-pentenoic acid, which are known to inhibit β-oxidation enzymes in animal cells. Acrylic acid completely inhibited PHA synthesis at a concentration of 4 mM in 40 mM octanoate-grown cells, but no inhibition of PHA synthesis occurred in 70 mM fructose-grown cells in the presence of 1 to 5 mM acrylic acid. 2-Bromooctanoic acid and 4-pentenoic acid were found to much inhibit PHA synthesis much more strongly in fructose-grown cells than in octanoate-grown cells over concentrations ranging from 1 to 5 mM. However, 2-bromooctanoic acid and 4-pentenoic acid did not inhibit cell growth at all in the fructose media. Especially, with the cells grown on fructose, 2-bromooctanoic acid exhibited a steep rise in the percent PHA synthesis inhibition over a small range of concentrations below 100 μM, a finding indicative of a very specific inhibition, whereas 4-pentenoic acid showed a broad, featureless concentration dependence, suggesting a rather nonspecific inhibition. The apparent inhibition constant Ki (the concentration for 50% inhibition of PHA synthesis) for 2

  1. Cytokine adsorbing columns.

    PubMed

    Taniguchi, Takumi

    2010-01-01

    Sepsis induces the activation of complement and the release of inflammatory cytokines such as TNF-alpha and IL-1beta. The inflammatory cytokines and nitric oxide induced by sepsis can decrease systemic vascular resistance, resulting in profound hypotension. The combination of hypotension and microvascular occlusion results in tissue ischemia and ultimately leads to multiple organ failure. Recently, several experimental and clinical studies have reported that treatment for adsorption of cytokines is beneficial during endotoxemia and sepsis. Therefore, the present article discusses cytokine adsorbing columns. These columns, such as CytoSorb, CYT-860-DHP, Lixelle, CTR-001 and MPCF-X, the structures of which vary significantly, have excellent adsorption rates for inflammatory cytokines such as TNF-alpha, IL-1beta, IL-6 and IL8. Many studies have demonstrated that treatment with cytokine adsorbing columns has beneficial effects on the survival rate and inflammatory responses in animal septic models. Moreover, several cases have been reported in which treatment with cytokine adsorbing columns is very effective in hemodynamics and organ failures in critically ill patients. Although further investigations and clinical trials are needed, in the future treatment with cytokine adsorbing columns may play a major role in the treatment of hypercytokinemia such as multiple organ failure and acute respiratory distress syndrome. Copyright 2010 S. Karger AG, Basel.

  2. Fermented Citrus reticulata (ponkan) fruit squeezed draff that contains a large amount of 4'-demethylnobiletin prevents MK801-induced memory impairment.

    PubMed

    Kawahata, Ichiro; Suzuki, Tatsuya; Rico, Evelyn Gutiérrez; Kusano, Shuichi; Tamura, Hiroshi; Mimaki, Yoshihiro; Yamakuni, Tohru

    2017-10-01

    A previous study reported biotransformation of a citrus peel polymethoxyflavone, nobiletin, by Aspergillus enabling production of 4'-demethylnobiletin, and the product's antimutagenic activity. However, the effects of fermented citrus peel on the basal forebrain-hippocampal system remain unidentified. Citrus reticulata (ponkan) fruit squeezed draffs are generated as mass waste in beverage factories. In this study using PC12D cells and cultured central nervous system neurons, we therefore examined whether Aspergillus kawachii-fermented citrus fruit squeezed draff could affect cAMP response element (CRE)- and choline acetyltransferase gene (ChAT) promoter region-mediated transcriptional activities relevant to memory formation and cholinergic function. Our current fermentation yielded approximately 80% nobiletin bioconversion, and a sample of hot-water extract of the fermented fruit squeezed draff was stronger than that of the unfermented one in facilitating CRE-mediated transcription in cultured hippocampal neurons as well as in PC12D cells. A sample of 0-80% ethanol-eluted fraction of Diaion HP-20 column-adsorbed components of the preparation obtained by the fermentation concentration-dependently and more strongly facilitated CRE-mediated transcription than did the fraction of the unfermented one in both cell culture systems. In a separate study, this polymethoxyflavone-rich fraction of the fermented fruit squeezed draff showed a potent ability to facilitate CRE-mediated and ChAT transcription in a co-culture of hippocampal neurons and basal forebrain neurons. Repeated oral gavage of mice with the fermented fraction sample prevented MK801-impaired memory formation in mice. These findings suggest that the 4'-demethylnobiletin-rich fraction prepared from the Aspergillus-fermented ponkan squeezed draff has a potential anti-dementia effect.

  3. Factors associated with the amount of public home care received by elderly and intellectually disabled individuals in a large Norwegian municipality.

    PubMed

    Døhl, Øystein; Garåsen, Helge; Kalseth, Jorid; Magnussen, Jon

    2016-05-01

    This study reports an analysis of factors associated with home care use in a setting in which long-term care services are provided within a publicly financed welfare system. We considered two groups of home care recipients: elderly individuals and intellectually disabled individuals. Routinely collected data on users of public home care in the municipality of Trondheim in October 2012, including 2493 people aged 67 years or older and 270 intellectually disabled people, were used. Multivariate regression analysis was used to analyse the relationship between the time spent in direct contact with recipients by public healthcare personnel and perceived individual determinants of home care use (i.e. physical disability, cognitive impairment, diagnoses, age and gender, as well as socioeconomic characteristics). Physical disability and cognitive impairment are routinely registered for long-term care users through a standardised instrument that is used in all Norwegian municipalities. Factor analysis was used to aggregate the individual items into composite variables that were included as need variables. Both physical disability and cognitive impairment were strong predictors of the amount of received care for both elderly and intellectually disabled individuals. Furthermore, we found a negative interaction effect between physical disability and cognitive impairment for elderly home care users. For elderly individuals, we also found significant positive associations between weekly hours of home care and having comorbidity, living alone, living in a service flat and having a safety alarm. The reduction in the amount of care for elderly individuals living with a cohabitant was substantially greater for males than for females. For intellectually disabled individuals, receiving services involuntarily due to severe behavioural problems was a strong predictor of the amount of care received. Our analysis showed that routinely collected data capture important predictors of home

  4. 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.

  5. Factors influencing antibiotics adsorption onto engineered adsorbents.

    PubMed

    Xia, Mingfang; Li, Aimin; Zhu, Zhaolian; Zhou, Qin; Yang, Weiben

    2013-07-01

    The study evaluated the adsorption of two antibiotics by four engineered adsorbents (hypercrosslinked resin MN-202, macroporous resin XAD-4, activated carbon F-400, and multi-walled carbon nanotubes (MWCNT)) from aqueous solutions. The dynamic results demonstrated the dominant influence of pore size in adsorption. The adsorption amounts of antibiotics on XAD-4 were attributed to the hydrophobic effect, whereas steric hindrance or micropore-filling played a main role in the adsorption of antibiotics by F-400 because of its high microporosity. Aside from F-400, similar patterns of pH-dependent adsorption were observed, implying the importance of antibiotic molecular forms to the adsorption process for adsorbents. Increasing the ionic concentration with CaC12 produced particular adsorption characteristics on MWCNT at pH 2.0 and F-400 at pH 8.0, which were attributed to the highly available contact surfaces and molecular sieving, respectively. Its hybrid characteristics incorporating a considerable portion of mesopores and micropores made hypercross linked MN-202 a superior antibiotic adsorbent with high adsorption capacity. Furthermore, the adsorption capacity of MWCNT on the basis of surface area was more advantageous than that of the other adsorbents because MWCNT has a much more compact molecular arrangement.

  6. 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

  7. 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

  8. Sequencing of the large dsDNA genome of Oryctes rhinoceros nudivirus using multiple displacement amplification of nanogram amounts of virus DNA.

    PubMed

    Wang, Yongjie; Kleespies, Regina G; Ramle, Moslim B; Jehle, Johannes A

    2008-09-01

    The genomic sequence analysis of many large dsDNA viruses is hampered by the lack of enough sample materials. Here, we report a whole genome amplification of the Oryctes rhinoceros nudivirus (OrNV) isolate Ma07 starting from as few as about 10 ng of purified viral DNA by application of phi29 DNA polymerase- and exonuclease-resistant random hexamer-based multiple displacement amplification (MDA) method. About 60 microg of high molecular weight DNA with fragment sizes of up to 25 kbp was amplified. A genomic DNA clone library was generated using the product DNA. After 8-fold sequencing coverage, the 127,615 bp of OrNV whole genome was sequenced successfully. The results demonstrate that the MDA-based whole genome amplification enables rapid access to genomic information from exiguous virus samples.

  9. A review on applicability of naturally available adsorbents for the removal of hazardous dyes from aqueous waste.

    PubMed

    Sharma, Pankaj; Kaur, Harleen; Sharma, Monika; Sahore, Vishal

    2011-12-01

    The effluent water of many industries, such as textiles, leather, paper, printing, cosmetics, etc., contains large amount of hazardous dyes. There is huge number of treatment processes as well as adsorbent which are available for the processing of this effluent water-containing dye content. The applicability of naturally available low cast and eco-friendly adsorbents, for the removal of hazardous dyes from aqueous waste by adsorption treatment, has been reviewed. In this review paper, we have provided a compiled list of low-cost, easily available, safe to handle, and easy-to-dispose-off adsorbents. These adsorbents have been classified into five different categories on the basis of their state of availability: (1) waste materials from agriculture and industry, (2) fruit waste, (3) plant waste, (4) natural inorganic materials, and (5) bioadsorbents. Some of the treated adsorbents have shown good adsorption capacities for methylene blue, congo red, crystal violet, rhodamine B, basic red, etc., but this adsorption process is highly pH dependent, and the pH of the medium plays an important role in the treatment process. Thus, in this review paper, we have made some efforts to discuss the role of pH in the treatment of wastewater.

  10. 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.

  11. Remediation of AMD using industrial waste adsorbents

    NASA Astrophysics Data System (ADS)

    Mohammed, Nuur Hani Bte; Yaacob, Wan Zuhairi Wan

    2016-11-01

    The study investigates the characteristic of industrial waste as adsorbents and its potential as heavy metals absorbents in AMD samples. The AMD sample was collected from active mine pond and the pH was measured in situ. The metal contents were analyzed by ICP-MS. The AMD water was very acidic (pH< 3.5), and the average heavy metals content in AMD were high especially in Fe (822.029 mg/l). Fly ash was found to be the most effective absorbent material containing high percentage of CaO (57.24%) and SiO2 (13.88%), followed by ladle furnace slag containing of high amount of CaO (51.52%) and Al2O3 (21.23%), while biomass ash consists of SiO2 (43.07%) and CaO (12.97%). Tank analysis display a huge changes due to pH value change from acidity to nearly neutral phases. After 50 days, fly ash remediation successfully increase the AMD pH values from pH 2.57-7.09, while slag change from acidity to nearly alkaline phase from pH 2.60-7.3 and biomass has change to pH 2.54-6.8. Fly ash has successfully remove Fe, Mn, Cu, and Ni. Meanwhile, slag sample displays as an effective adsorbent to adsorb more Pb and Cd in acid mine drainage.

  12. 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

  13. Diffusion Monte Carlo simulations of gas phase and adsorbed D2-(H2)n clusters

    NASA Astrophysics Data System (ADS)

    Curotto, E.; Mella, M.

    2018-03-01

    We have computed ground state energies and analyzed radial distributions for several gas phase and adsorbed D2(H2)n and HD(H2)n clusters. An external model potential designed to mimic ionic adsorption sites inside porous materials is used [M. Mella and E. Curotto, J. Phys. Chem. A 121, 5005 (2017)]. The isotopic substitution lowers the ground state energies by the expected amount based on the mass differences when these are compared with the energies of the pure clusters in the gas phase. A similar impact is found for adsorbed aggregates. The dissociation energy of D2 from the adsorbed clusters is always much higher than that of H2 from both pure and doped aggregates. Radial distributions of D2 and H2 are compared for both the gas phase and adsorbed species. For the gas phase clusters, two types of hydrogen-hydrogen interactions are considered: one based on the assumption that rotations and translations are adiabatically decoupled and the other based on nonisotropic four-dimensional potential. In the gas phase clusters of sufficiently large size, we find the heavier isotopomer more likely to be near the center of mass. However, there is a considerable overlap among the radial distributions of the two species. For the adsorbed clusters, we invariably find the heavy isotope located closer to the attractive interaction source than H2, and at the periphery of the aggregate, H2 molecules being substantially excluded from the interaction with the source. This finding rationalizes the dissociation energy results. For D2-(H2)n clusters with n ≥12 , such preference leads to the desorption of D2 from the aggregate, a phenomenon driven by the minimization of the total energy that can be obtained by reducing the confinement of (H2)12. The same happens for (H2)13, indicating that such an effect may be quite general and impact on the absorption of quantum species inside porous materials.

  14. 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.

  15. Rotary adsorbers for continuous bulk separations

    DOEpatents

    Baker, Frederick S [Oak Ridge, TN

    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.

  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

    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.more » 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

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

    SciTech Connect

    Brown, Suree; Chatterjee, Sabornie; Li, Meijun

    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

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

    DOE PAGES

    Brown, Suree; Chatterjee, Sabornie; Li, Meijun; ...

    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

  19. Bioavailability of organic and inorganic phosphates adsorbed on short-range ordered aluminum precipitate.

    PubMed

    Shang, C; Caldwell, D E; Stewart, J W; Tiessen, H; Huang, P M

    1996-01-01

    A nonreductive community-level study of P availability was conducted using various forms of adsorbed P. Orthophosphate (Pi), inositol hexaphosphate (IHP), and glucose 6-phosphate (G6P) were adsorbed to a short-range ordered Al precipitate. These bound phosphates provided a P source sufficient to support the growth of microbial communities from acidic Brazilian soils (oxisols). Adsorbed IHP, the most abundant form of organic phosphate in most soils, had the lowest bioavailability among the three phosphates studied. Adsorbed G6P and Pi were almost equally available. The amount of adsorbed Pi (1 cmol P kg(-1)) required to support microbial growth was at least 30 times less than that of IHP (30 cmol P kg(-1)). With increased surface coverage, adsorbed IHP became more bioavailable. This availability was attributed to a change in the structure of surface complexes and presumably resulted from the decreased number of high-affinity surface sites remaining at high levels of coverage. It thus appears that the bioavailability of various forms of adsorbed phosphate was determined primarily by the stability of the phosphate-surface complexes that they formed, rather than by the total amount of phosphate adsorbed. IHP, having the potential to form stable multiple-ring complexes, had the highest surface affinity and the lowest bioavailability. Bioaggregates consisting of bacteria and Al precipitate were observed and may be necessary for effective release of adsorbed P. Bacteria in the genera Enterobacter and Pseudomonas were the predominate organisms selected during these P-limited enrichments.

  20. [Concentrated adsorbed, cultured antirabies vaccine].

    PubMed

    Dulina, A V; Shafeeva, R S; Morogova, V M; Krutilina, D V; Nigamov, F N

    1980-11-01

    In animal experiments the antigenic activity of adsorbed concentrated tissue-culture rabies vaccine was shown to be significantly higher in comparison with the nonadsorbed concentrated preparation when introduced in 2 intramuscular injections at an interval of 21 and 30 days, as well as in comparison with commercial tissue-culture vaccine when introduced subcutaneously in a 14-day course of daily injections.

  1. 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.

  2. Novel adsorbent for DNA adsorption: Fe(3+)-attached sporopollenin particles embedded composite cryogels.

    PubMed

    Ceylan, Şeyda; Odabaşı, Mehmet

    2013-12-01

    The aim of this study is to prepare supermacroporous cryogels embedded with Fe(3+)-attached sporopollenin particles (Fe(3++)-ASPs) having large surface area for high DNA adsorption capacity. Supermacroporous poly(2-hydroxyethyl methacrylate) (PHEMA)-based monolithic cryogel column embedded with Fe3+(+)-ASPs was prepared by radical cryo-copolymerization of 2-hydroxyethyl methacrylate (HEMA) with N,N´-methylene- bis-acrylamide (MBAAm) as cross-linker directly in a plastic syringe for DNA adsorption studies. Firstly, Fe3+(+) ions were attached to the sporopollenin particles (SPs), then the supermacroporous PHEMA cryogel with embedded Fe(3++)-ASPs was produced by free radical polymerization using N,N,N´, N´-Tetramethylethylenediamine (TEMED) and ammonium persulfate (APS) as initiator/activator pair in an ice bath. Optimum conditions of adsorption experiments were performed at pH 6.0 (0.02 M Tris buffer containing 0.2 M NaCl), with flow rate of 0.5 mL/min, and at 5°C. The maximum amount of DNA adsorption from aqueous solution was very high (109 mg/g SPs) with initial concentration of 3 mg/mL. It was observed that DNA could be repeatedly adsorbed and desorbed with this composite cryogel without significant loss of adsorption capacity. As a result, higher amounts of DNA adsorbed these composite cryogels are expected to be good candidate for achieving higher removal of anti-DNA antibodies from systemic lupus erythematosus (SLE) patients plasma.

  3. 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.

  4. Uptake of uranium from seawater by amidoxime-based polymeric adsorbent marine testing

    SciTech Connect

    Tsouris, C.; Kim, J.; Oyola, Y.

    2013-07-01

    Amidoxime-based polymer adsorbents in the form of functionalized fibers were prepared at the Oak Ridge National Laboratory (ORNL) and screened in laboratory experiments, in terms of uranium uptake capacity, using spiked uranium solution and seawater samples. Batch laboratory experiments conducted with 5-gallon seawater tanks provided equilibrium information. Based on results from 5-gallon experiments, the best adsorbent was selected for field-testing of uranium adsorption from seawater. Flow-through column tests have been performed at different marine sites to investigate the uranium uptake rate and equilibrium capacity under diverse biogeochemistry. The maximum amount of uranium uptake from seawater tests at Sequim, WA, wasmore » 3.3 mg U/g adsorbent after eight weeks of contact of the adsorbent with seawater. This amount was three times higher than the maximum adsorption capacity achieved in this study by a leading adsorbent developed by the Japan Atomic Energy Agency (JAEA), which was 1.1 mg U/g adsorbent at equilibrium. The initial uranium uptake rate of the ORNL adsorbent was 2.6 times higher than that of the JAEA adsorbent under similar conditions. A mathematical model derived from the mass balance of uranium was employed to describe the data. (authors)« less

  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. 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.

  7. Quantum impurity models for magnetic adsorbates on superconductor surfaces

    NASA Astrophysics Data System (ADS)

    Žitko, Rok

    2018-05-01

    Magnetic atoms adsorbed on surfaces have a quenched orbital moment while their ground-state spin multiplet is partially split as a consequence of the spin-orbit coupling which, even if intrinsically weak, has a large effect due to the abrupt change of the potential at the surface. Such metal adsorbates should be modelled using quantum impurity models that include the relevant internal degrees of freedom and the interaction terms, in particular the magnetic anisotropy and the Kondo exchange coupling. When adsorbed on superconducting surfaces, these impurities have complex spectra of sub-gap excitations due to magnetic anisotropy splitting and Kondo screening. Both anisotropy splitting and Zeeman splitting due to the external magnetic field are significantly renormalized by the coupling to the substrate electrons. In this work I discuss the quantum-to-classical crossover and the applicability of classical static-local-spin picture for discussing magnetic nanostructures on superconductors.

  8. Uptake of Uranium from Seawater by Amidoxime-Based Polymeric Adsorbent: Field Experiments, Modeling, and Updated Economic Assessment

    SciTech Connect

    Kim, Jungseung; Tsouris, Constantinos; Oyola, Yatsandra

    2014-04-09

    Uranium recovery from seawater has been investigated for several decades for the purpose of securing nuclear fuel for energy production. In this study, field column experiments have been performed at the Marine Sciences Laboratory of the Pacific Northwest National Laboratory (PNNL) using a laboratory-proven, amidoxime-based polymeric adsorbent developed at the Oak Ridge National Laboratory (ORNL). The adsorbent was packed either in in-line filters or in flow-through columns. The maximum amount of uranium uptake from seawater was 3.3 mg of U/g of adsorbent after 8 weeks of contact between the adsorbent and seawater. This uranium adsorption amount was about 3 timesmore » higher than the maximum amount achieved in this study by a leading adsorbent developed at the Japan Atomic Energy Agency (JAEA).« less

  9. 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.

  10. Oxygen sensor via the quenching of room-temperature phosphorescence of perdeuterated phenanthrene adsorbed on Whatman 1PS filter paper.

    PubMed

    Ramasamy, S M; Hurtubise, R J

    1998-11-01

    Perdeuterated phenanthrene (d-phen) exhibits strong room-temperature phosphorescence (RTP) when adsorbed on Whatman 1PS filter paper. An oxygen sensor was developed that depends on oxygen quenching of RTP intensity of adsorbed d-phen. The system designed employed a continuous flow of nitrogen or nitrogen-air onto the adsorbed phosphor. The sensor is simple to prepare and needs no elaborate fabrication procedure, but did show a somewhat drifting baseline for successive determinations of oxygen. Nevertheless, very good reproducibility was achieved with the RTP quenching data by measuring the RTP intensities just before and at the end of each oxygen determination. The calibration plots gave a nonlinear relationship over the entire range of oxygen (0-21%). However, a linear range was obtained up to 1.10% oxygen. A detection limit of 0.09% oxygen in dry nitrogen was acquired. Also, carbon dioxide was found to have a minimal effect on the RTP quenching. Thus, oxygen could be measured accurately in relatively large amounts of carbon dioxide. The performance of the oxygen sensor was evaluated by comparing data obtained with a commercial electrochemical trace oxygen analyzer. Also, additional information on the quenching phenomena for this system was obtained from the RTP lifetime data acquired at various oxygen contents.

  11. 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...

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

    SciTech Connect

    Gill, Gary A.; Kuo, Li -Jung; Janke, Christopher James

    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

  13. 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; ...

    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

  14. 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.

    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 studiedmore » 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.« less

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

    SciTech Connect

    Janke, Chris; Yatsandra, Oyola; Mayes, Richard

    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.

  16. 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.

  17. NOx adsorber and method of regenerating same

    DOEpatents

    Endicott, Dennis L [Peoria, IL; Verkiel, Maarten [Metamora, IL; Driscoll, James J [Dunlap, IL

    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.

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

    PubMed

    Steiner, M; Boller, M

    2006-01-01

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

  19. Lysozyme adsorption onto mesoporous materials: effect of pore geometry and stability of adsorbents.

    PubMed

    Vinu, Ajayan; Miyahara, Masahiko; Hossain, Kazi Zakir; Takahashi, Motoi; Balasubramanian, Veerappan Vaithilingam; Mori, Toshiyuki; Ariga, Katsuhiko

    2007-03-01

    In this paper, adsorption of lysozyme onto two kinds of mesoporous adsorbents (KIT-5 and AISBA-15) has been investigated and the results on the effects of pore geometry and stability of the adsorbents are also discussed. The KIT-5 mesoporous silica materials possess cage-type pore geometry while the AISBA-15 adsorbent has mesopores of cylindrical type with rather large diameter (9.7 nm). Adsorption of lysozyme onto AISBA-15 aluminosilicate obeys a Langmuir isotherm, resulting in pore occupation of 25 to 30%. In contrast, the KIT-5 adsorbents showed very small adsorption capacities for the lysozyme adsorption, typically falling in 6 to 13% of pore occupation. The cage-type KIT-5 adsorbents have narrow channel (4 to 6 nm) where penetration of the lysozyme (3 x 3 x 4.5 nm) might be restricted. The KIT-5 adsorbent tends to collapse after long-time immersion in water, as indicated by XRD patterns, while the AISBA-15 adsorbent retains its regular structure even after immersion in basic water for 4 days. These facts confirm superiority of the AISBA-15 as an adsorbent as compared with the KIT-5 mesoporous silicates. This research strikingly demonstrates the selection of mesoporous materials is crucial to achieve efficient immobilization of biomaterials in aqueous environment.

  20. Selective Gas Capture Ability of Gas-Adsorbent-Incorporated Cellulose Nanofiber Films.

    PubMed

    Shah, Kinjal J; Imae, Toyoko

    2016-05-09

    The 2,2,6,6-tetramethylpiperidine-1-oxyl radical-oxidized cellulose nanofibers (TOCNF) were hybridized with cation and anion-exchange organoclays, where poly(amido amine) dendrimers were loaded to enhance the functionality of gas adsorption, since dendrimers have the high adsorbability and the enough selectivity on the gas adsorption. The thin films were prepared from the organoclay-TOCNF hybrids and supplied to the gas adsorption. The adsorption of CO2 and NH3 gases increased with an increasing amount of organoclays in TOCNF films, but the behavior of the increase depended on gases, clays, and dendrimers. The hydrotalcite organoclay-TOCNF films displayed the highest adsorption of both gases, but the desorption of CO2 gas from hydrotalcite organoclay-TOCNF films was drastically high in comparison with the other systems. While the CO2 gas is adsorbed and remained on cationic dendrimer sites in cation-exchange organoclay-TOCNF films, the CO2 gas is adsorbed on cationic clay sites in anion exchange organoclay-TOCNF films, and it is easily desorbed from the films. The NH3 adsorption is inversive to the CO2 adsorption. Then the CO2 molecules adsorbed on the cationic dendrimers and the NH3 molecules adsorbed on the anionic dendrimers are preferably captured in these adsorbents. The present research incorporated dendrimers will be contributing to the development of gas-specialized adsorbents, which are selectively storable only in particular gases.

  1. Hydroxyapatite-gelatin nanocomposite as a novel adsorbent for nitrobenzene removal from aqueous solution

    NASA Astrophysics Data System (ADS)

    Wei, Wei; Sun, Rong; Jin, Zhu; Cui, Jing; Wei, Zhenggui

    2014-02-01

    A novel adsorbent of hydroxyapatite-gelatin (HAP-GEL) nanocomposite was developed for nitrobenzene removal from aqueous solution. The adsorbent was characterized and its performance in nitrobenzene removal was evaluated. The effects of contact time, adsorbent dosage, temperature, pH, ionic strength, humic acid, and the presence of solvent on nitrobenzene adsorption, as well as the thermodynamic parameters for adsorption equilibrium were also investigated. Results showed that HAP-GEL nanocomposite possessed good adsorption ability to nitrobenzene. The adsorption process was fast, and it reached a steady state after only 1 min. Nitrobenzene removal was increased with an increasing amount of adsorbent dosage but decreased as the temperature and pH increased. Meanwhile the amount of nitrobenzene adsorbed decreased with an increase of ionic strength from 0.01 to 1.0 mol/L and humic acid from 10 to 50 mg/L. The adsorption isotherm studies showed that both Langmuir and Freundlich models could fit the experimental data well, and the maximum adsorption capacity was estimated to be 42.373 mg/g. The thermodynamic parameters suggested that the adsorption of nitrobenzene on HAP-GEL nanocomposite was physisorption, spontaneous and exothermic in nature. Findings of this study demonstrated the potential utility of the HAP-GEL nanocomposite as an effective adsorbent for nitrobenzene removal from aqueous solution.

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

    PubMed

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

    2015-12-21

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

  3. 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.

  4. 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.

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

    SciTech Connect

    Zhang, Xiaoyun; Qin, Hongyan; Zhang, Sisi

    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–vismore » 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.« less

  6. To-date spacecraft applications and demonstration testing results, and future product development for new molecular adsorber technologies

    NASA Technical Reports Server (NTRS)

    Thomson, Shaun; Hansen, Patricia; Straka, Sharon; Chen, Philip; Triolo, Jack; Bettini, Ron; Carosso, Paolo; Carosso, Nancy

    1997-01-01

    The use of molecular adsorbers, in order to aid in the reduction of the spacecraft contamination levels, is discussed. Molecular adsorbers are characterized by an extremely large surface area, molecularly-porous substructure, and processing charged sites capable of retaining molecular contaminant species. Molecular adsorbers were applied on two Hubble Space Telescope servicing missions, as well as on the tropical rainfall measuring mission. The use of molecular adsorbers carries the potential for low cost, easy fabrication and integration of reliable means for reducing the contamination level around spacecraft.

  7. 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...

  8. Monitoring by Control Technique - Activated Carbon Adsorber

    EPA Pesticide Factsheets

    Stationary source emissions monitoring is required to demonstrate that a source is meeting the requirements in Federal or state rules. This page is about Activated Carbon Adsorber control techniques used to reduce pollutant emissions.

  9. Chitin Adsorbents for Toxic Metals: A Review

    PubMed Central

    Anastopoulos, Ioannis; Bhatnagar, Amit; Bikiaris, Dimitrios N.; Kyzas, George Z.

    2017-01-01

    Wastewater treatment is still a critical issue all over the world. Among examined methods for the decontamination of wastewaters, adsorption is a promising, cheap, environmentally friendly and efficient procedure. There are various types of adsorbents that have been used to remove different pollutants such as agricultural waste, compost, nanomaterials, algae, etc., Chitin (poly-β-(1,4)-N-acetyl-d-glucosamine) is the second most abundant natural biopolymer and it has attracted scientific attention as an inexpensive adsorbent for toxic metals. This review article provides information about the use of chitin as an adsorbent. A list of chitin adsorbents with maximum adsorption capacity and the best isotherm and kinetic fitting models are provided. Moreover, thermodynamic studies, regeneration studies, the mechanism of adsorption and the experimental conditions are also discussed in depth. PMID:28067848

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

    PubMed

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

    2016-12-05

    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. Copyright © 2016 Elsevier B.V. All rights reserved.

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

    NASA Astrophysics Data System (ADS)

    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.

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

    PubMed

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

    2013-10-04

    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. Copyright © 2013 Elsevier B.V. All rights reserved.

  13. CO adsorption on ion bombarded Ni(111): characterization by photoemission from adsorbed xenon

    NASA Astrophysics Data System (ADS)

    Fu, Sabrina S.; Malafsky, Geoffrey P.; Hsu, David S. Y.

    1993-11-01

    The adsorption of CO on Ni(111), ion bombarded with various fluences of 1.0 keV Ar + ions, has been investigated using photoemission from adsorbed xenon (PAX). After ion bombardment of the Ni(111) surface, various amounts of CO were adsorbed, followed by adsorption of xenon at 85 K. Two pressures of xenon were used in examining the 3d {5}/{2} peak of xenon: 5 × 10 -6 and 7 × 10 -10 Torr. PAX data taken at both pressures show that CO selectively adsorbs onto the defect (step) sites created by ion bombardment. In addition, it was found that the amount of CO which could occupy a defect site previously occupied by one Xe atom varied from 10 to 2.5, depending on the ion fluence.

  14. 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.

  15. Nanofiber adsorbents for high productivity downstream processing.

    PubMed

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

    2013-04-01

    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. To improve the purification productivity of biological molecules by chromatography, cellulose nanofiber adsorbents were fabricated and assembled into a cartridge and filter holder format with a volume of 0.15 mL, a bed height of 0.3 mm and diameter of 25 mm. The present study investigated the performance of diethylaminoethyl (DEAE) derivatized regenerated cellulose nanofiber adsorbents based on criteria including mass transfer and flow properties, binding capacity, and fouling effects. Our results show that nanofibers offer higher flow and mass transfer properties. The non-optimized DEAE-nanofiber adsorbents indicate a binding capacity of 10% that of packed bed systems with BSA as a single component system. However, they operate reproducibly at flowrates of a hundred times that of packed beds, resulting in a potential productivity increase of 10-fold. Lifetime studies showed that this novel adsorbent material operated reproducibly with complex feed material (centrifuged and 0.45 µm filtered yeast homogenate) and harsh cleaning-in-place conditions over multiple cycles. DEAE nanofibers showed superior operating performance in permeability and fouling over conventional adsorbents indicating their potential for bioseparation applications. Copyright © 2012 Wiley Periodicals, Inc.

  16. TiO2/porous adsorbents: Recent advances and novel applications.

    PubMed

    MiarAlipour, Shayan; Friedmann, Donia; Scott, Jason; Amal, Rose

    2018-01-05

    This article reviews two interrelated areas of research: the first is the use of TiO 2 -supported adsorbent materials as enhanced heterogeneous photocatalysts and their application to various reactions for organic pollutant removal from air and water; the second is the combination of adsorbent materials with TiO 2 photocatalysts which aims to efficiently regenerate adsorbent materials using illumination. By reviewing both areas of research, the following topics are covered; (i) photocatalytic activation of TiO 2; (ii) related properties of photocatalytic TiO 2; (iii) shortcomings of photocatalytic processes; (iv) preparation methods of composite TiO 2 /adsorbent materials and their photocatalytic performance; (v) properties of common adsorbents and their applications for pollutant removal from air and water; (vi) adsorbent regeneration methods and their economic and operational issues; (vii) conclusions and future outlooks. This topic has not been previously reviewed to such an extent, and considerable knowledge can be gained from assembling the large number of studies on adsorption-photocatalysis combinations. As such, this review provides guidance for researchers working in the fields of environmental and chemical engineering focussing on organic pollutant removal and the engineering of new high performance photocatalytic TiO 2 -supported porous adsorbent materials. Copyright © 2017 Elsevier B.V. All rights reserved.

  17. Possible pore size effects on the state of tris(8-quinolinato)aluminum(III) (Alq3) adsorbed in mesoporous silicas and their temperature dependence.

    PubMed

    Tagaya, Motohiro; Ogawa, Makoto

    2008-12-07

    The states of tris(8-quinolinato)aluminum(III) (Alq3) adsorbed in mesoporous silicas with different pore sizes (2.5, 3.1 and 5.0 nm) were investigated. Alq3 was successfully occluded into the mesoporous silicas from solution and the adsorbed amount of Alq3 per BET surface area was effectively controlled by changing the added amount Alq3 to the solution. The state of Alq3 in the mesopore varied depending on the pore size as well as the adsorbed amount of Alq3 as revealed by variation of the photoluminescence spectra. The luminescence of the adsorbed Alq3 was found to be temperature-dependent, indicating the mobility of the adsorbed Alq3 to temperature variations. The temperature-dependence also depended on the pore size. The guest-guest interactions between Alq3 molecules as well as the host-guest interactions between Alq3 and the mesopore were controlled by the pore size.

  18. Direct observation of the photodegradation of anthracene and pyrene adsorbed onto mangrove leaves.

    PubMed

    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.

  19. 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

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

    USDA-ARS?s Scientific Manuscript database

    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...

  1. A Recombinant Potato virus Y Infectious Clone Tagged with the Rosea1 Visual Marker (PVY-Ros1) Facilitates the Analysis of Viral Infectivity and Allows the Production of Large Amounts of Anthocyanins in Plants

    PubMed Central

    Cordero, Teresa; Mohamed, Mohamed A.; López-Moya, Juan-José; Daròs, José-Antonio

    2017-01-01

    Potato virus Y (PVY) is a major threat to the cultivation of potato and other solanaceous plants. By inserting a cDNA coding for the Antirrhinum majus Rosea1 transcription factor into a PVY infectious clone, we created a biotechnological tool (PVY-Ros1) that allows infection by this relevant plant virus to be tracked by the naked eye with no need for complex instrumentation. Rosea1 is an MYB-type transcription factor whose expression activates the biosynthesis of anthocyanin pigments in a dose-specific and cell-autonomous manner. Our experiments showed that the mechanical inoculation of solanaceous plants with PVY-Ros1 induced the formation of red infection foci in inoculated tissue and solid dark red pigmentation in systemically infected tissue, which allows disease progression to be easily monitored. By using silver nanoparticles, a nanomaterial with exciting antimicrobial properties, we proved the benefits of PVY-Ros1 to analyze novel antiviral treatments in plants. PVY-Ros1 was also helpful for visually monitoring the virus transmission process by an aphid vector. Most importantly, the anthocyanin analysis of infected tobacco tissues demonstrated that PVY-Ros1 is an excellent biotechnological tool for molecular farming because it induces the accumulation of larger amounts of anthocyanins, antioxidant compounds of nutritional, pharmaceutical and industrial interest, than those that naturally accumulate in some fruits and vegetables well known for their high anthocyanin content. Hence these results support the notion that the virus-mediated expression of regulatory factors and enzymes in plants facilitates easy quick plant metabolism engineering. PMID:28428782

  2. Interplay of polyelectrolytes with different adsorbing surfaces

    NASA Astrophysics Data System (ADS)

    Xie, Feng

    We study the adsorption of polyelectrolytes from solution onto different adsorbing surfaces, focusing on the electrostatic interactions. Measurements of the surface excess, fractional ionization of chargeable groups, segmental orientation, and adsorption kinetics were made using Fourier transform infrared spectroscopy in the mode of attenuated total reflection. Different adsorbing surfaces, from single solid surfaces, solid surfaces modified with adsorbed polymer layer, to fluid-like surfaces-biomembranes were adopted. Both atomic force microscopy (AFM) and fluorescent techniques were employed to investigate the fluid-like surfaces in the absence and in the presence of polyelectrolytes. The work focuses on three primary issues: (i) the charge regulation of weak polyelectrolytes on both homogeneous and heterogeneous surfaces, (ii) the dynamics of adsorption when the surface possesses reciprocal mobility, i.e., biomembrane surface, and (iii) the structural and dynamical properties of the fluid-like surfaces interacting with polyelectrolytes. We find that the ionization of chargeable groups in weak polyelectrolytes is controlled by the charge balance between the adsorbates and the surfaces. A new interpretation of ionization in the adsorbed layer provides a new insight into the fundamental problem of whether ions of opposite charge associate or remain separate. Bjerrum length is found to be a criterion for the onset of surface ionization suppression, which helps to predict and control the conformation transition of proteins. In addition to the effect of different surfaces on the adsorption behavior of polyelectrolytes, we also focused on the response of the surfaces to the adsorbates. Chains that encountered sparsely-covered surfaces spread to maximize the number of segment-surface contacts at rates independent of the molar mass. Surface reconstruction rather than molar mass of the adsorbing molecules appeared to determine the rate of spreading. This contrasts starkly

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

    PubMed Central

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

    2017-01-01

    A multi-functional polystyrene based adsorbent (NKU-9) with a unique mesoporous and a high surface area was prepared by suspension polymerization for removal of therapeutic toxins in blood purification. The adsorbent produced had an almost equal amount of mesopore distribution in the range from 2 to 50 nm. The adsorption of serum toxins with different molecular weights were examined by in vitro adsorption assays and compared with some clinical currently used adsorbents such as HA-330, Cytosorb and BL-300 which are produced by China, America and Japan, respectively. Test results indicated that the adsorption rate for pentobarbital by NKU-9 was 81.24% which is nearly as high as HA-330 (81.44%). The latter adsorbent is currently used for acute detoxification treatment in China. To reach adsorption equilibrium, NKU-9 was faster than HA-330, which implies short treatment time. For the removal of middle molecular toxins such as β2-microglobulin (98.88%), NKU-9 performed better adsorptive selectivity than Cytosorb (92.80%). In addition, NKU-9 showed high performance for the removal of albumin-bound toxins (e.g., bilirubin), and its adsorption rate for total bilirubin (80.79%) in plasma was 8.4% higher than that of anion exchange resin BL-300 which is currently used to eliminate bilirubin in clinic. Therefore, our results indicate that the newly developed adsorbent with a wide distribution and almost equal amount of mesopores is a multifunctional adsorbent for high efficient removal of serum toxins with different molecular weights which might be an excellent blood purification adsorbent especially to treat diseases that conventional medical methods are low or not efficient. PMID:28149527

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

    PubMed

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

    2017-02-01

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

  5. Viscoelastic properties of cationic starch adsorbed on quartz studied by QCM-D.

    PubMed

    Tammelin, Tekla; Merta, Juha; Johansson, Leena-Sisko; Stenius, Per

    2004-12-07

    The adsorption and viscoelastic properties of layers of a cationic polyelectrolyte (cationic starch, CS, with 2-hydroxy-3-trimethylammoniumchloride as the substituent) adsorbed from aqueous solutions (pH 7.5, added NaCl 0, 1, 100, and 500 mM) on silica were studied with a quartz crystal microbalance with dissipation (QCM-D). Three different starches were investigated (weight-average molecular weights M(w) approximately 8.7 x 10(5) and 4.5 x 10(5) with degree of substitution DS = 0.75 and M(w) approximately 8.8 x 10(5) with DS = 0.2). At low ionic strength, the adsorbed layers are thin and rigid and the amount adsorbed can be calculated using the Sauerbrey equation. When the ionic strength is increased, significant changes take place in the amount of adsorbed CS and the viscoelasticity of the adsorbed layer. These changes were analyzed assuming that the layer can be described as a Voigt element on a rigid surface in contact with purely viscous solvent. It was found that CS with low charge density forms a thicker and more mobile layer with higher viscosity and elasticity than CS with high charge density. The polymers adsorbed on the silica even when the ionic strength was so high that electrostatic interactions were effectively screened. At this high ionic strength, it was possible to study the effect of molecular weight and molecular weight distribution of the CS on the properties of the adsorbed film. Increasing the molecular weight of CS resulted in a larger hydrodynamic thickness. CS with a narrow molecular weight distribution formed a more compact and rigid layer than broadly distributed CS, presumably due to the better packing of the molecules.

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

    PubMed

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

    2015-01-20

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

  7. 3D Oxidized Graphene Frameworks: An Efficient Adsorbent for Methylene Blue

    NASA Astrophysics Data System (ADS)

    Pandey, Abhishek; Deb, Madhurima; Tiwari, Shreya; Pawar, Pranav Bhagwan; Saxena, Sumit; Shukla, Shobha

    2018-04-01

    Extraordinary properties of graphene and its derivatives have found application in varied areas such as energy, electronics, optical devices and sensors, to name a few. Large surface area along with specialized functional groups make these materials attractive for removal of dye molecules in solution via adsorption. Industrial effluents contain large amounts of toxic chemicals resulting in pollution of water bodies, which pose environmental hazards in general. Here we report application of 3D oxidized graphene frameworks in the efficient removal of cationic dye molecules such as methylene blue via adsorption. Systematic parametric studies investigating the effect of the initial dye concentration, pH and contact time have been performed. Spectroscopic analysis of the filtrate suggests that tortuous paths in 3D oxidized graphene frameworks result in efficient removal of dye molecules due to enhanced interaction. The hydroxyl groups retained in these 3D oxidized graphene frameworks facilitate adsorption of the dye molecules while passing through the adsorbent. pH studies suggest that maximum removal efficiency for methylene blue was achieved at pH value of 9. The results suggest that these 3D oxidized graphene frameworks can be used for purification of large volumes of contaminated water from cationic dyes in waste water treatment plants.

  8. 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. Copyright © 2011 Elsevier B.V. All rights reserved.

  9. 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. Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  10. Membrane Perturbation Induced by Interfacially Adsorbed Peptides

    PubMed Central

    Zemel, Assaf; Ben-Shaul, Avinoam; May, Sylvio

    2004-01-01

    The structural and energetic characteristics of the interaction between interfacially adsorbed (partially inserted) α-helical, amphipathic peptides and the lipid bilayer substrate are studied using a molecular level theory of lipid chain packing in membranes. The peptides are modeled as “amphipathic cylinders” characterized by a well-defined polar angle. Assuming two-dimensional nematic order of the adsorbed peptides, the membrane perturbation free energy is evaluated using a cell-like model; the peptide axes are parallel to the membrane plane. The elastic and interfacial contributions to the perturbation free energy of the “peptide-dressed” membrane are evaluated as a function of: the peptide penetration depth into the bilayer's hydrophobic core, the membrane thickness, the polar angle, and the lipid/peptide ratio. The structural properties calculated include the shape and extent of the distorted (stretched and bent) lipid chains surrounding the adsorbed peptide, and their orientational (C-H) bond order parameter profiles. The changes in bond order parameters attendant upon peptide adsorption are in good agreement with magnetic resonance measurements. Also consistent with experiment, our model predicts that peptide adsorption results in membrane thinning. Our calculations reveal pronounced, membrane-mediated, attractive interactions between the adsorbed peptides, suggesting a possible mechanism for lateral aggregation of membrane-bound peptides. As a special case of interest, we have also investigated completely hydrophobic peptides, for which we find a strong energetic preference for the transmembrane (inserted) orientation over the horizontal (adsorbed) orientation. PMID:15189858

  11. 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.

  12. 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.

  13. Adsorbent catalytic nanoparticles and methods of using the same

    DOEpatents

    Slowing, Igor Ivan; Kandel, Kapil

    2017-01-31

    The present invention provides an adsorbent catalytic nanoparticle including a mesoporous silica nanoparticle having at least one adsorbent functional group bound thereto. The adsorbent catalytic nanoparticle also includes at least one catalytic material. In various embodiments, the present invention provides methods of using and making the adsorbent catalytic nanoparticles. In some examples, the adsorbent catalytic nanoparticles can be used to selectively remove fatty acids from feedstocks for biodiesel, and to hydrotreat the separated fatty acids.

  14. 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.

  15. Efficiency of basalt zeolite and Cuban zeolite to adsorb ammonia released from poultry litter.

    PubMed

    Nuernberg, Giselle B; Moreira, Marcelo A; Ernani, Paulo R; Almeida, Jaime A; Maciel, Tais M

    2016-12-01

    Confined poultry production is an important livestock activity, which generates large amounts of waste associated with the potential for environmental pollution and ammonia (NH 3 ) emissions. The release of ammonia negatively affects poultry production and decreases the N content of wastes that could be used as soil fertilizers. The objective of this study was to evaluate a low-cost, simple and rapid method to simulate ammonia emissions from poultry litter as well as to quantify the reduction in the ammonia emissions to the environment employing two adsorbent zeolites, a commercial Cuban zeolite (CZ) and a ground basalt Brazilian rock containing zeolite (BZ). The experiments were conducted in a laboratory, in 2012-2013. The zeolites were characterized by X-ray diffraction (XRD), X-ray fluorescence spectrometry (XRF), physical adsorption of N 2 (BET) and scanning electron microscopy (SEM). Ammonia released from poultry litter and its simulation from NH 4 OH solution presented similar capture rates of 7.99 × 10 -5 and 7.35 × 10 -5  mg/h, respectively. Both zeolites contain SiO 2 and Al 2 O 3 as major constituents, with contents of 84% and 12% in the CZ, and 51% and 12% in the BZ, respectively, besides heulandite groups. Their BET surface areas were 89.4 and 11.3 m 2  g -1 , respectively, and the two zeolites had similar surface morphologies. The zeolites successfully adsorbed the ammonia released, but CZ was more efficient than BZ, since to capture all of the ammonia 5 g of CZ and 20 g of BZ were required. This difference is due to higher values for the superficial area, porosity, CEC and acid site strength of CZ relatively to BZ. The proposed methodology was shown to be an efficient method to simulate and quantify the ammonia released from poultry litter. Copyright © 2016 Elsevier Ltd. All rights reserved.

  16. 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

  17. Correlation between surface morphology and surface forces of protein A adsorbed on mica.

    PubMed Central

    Ohnishi, S; Murata, M; Hato, M

    1998-01-01

    We have investigated the morphology and surface forces of protein A adsorbed on mica surface in the protein solutions of various concentrations. The force-distance curves, measured with a surface force apparatus (SFA), were interpreted in terms of two different regimens: a "large-distance" regimen in which an electrostatic double-layer force dominates, and an "adsorbed layer" regimen in which a force of steric origin dominates. To further clarify the forces of steric origin, the surface morphology of the adsorbed protein layer was investigated with an atomic force microscope (AFM) because the steric repulsive forces are strongly affected by the adsorption mode of protein A molecules on mica. At lower protein concentrations (2 ppm, 10 ppm), protein A molecules were adsorbed "side-on" parallel to the mica surfaces, forming a monolayer of approximately 2.5 nm. AFM images at higher concentrations (30 ppm, 100 ppm) showed protruding structures over the monolayer, which revealed that the adsorbed protein A molecules had one end oriented into the solution, with the remainder of each molecule adsorbed side-on to the mica surface. These extending ends of protein A overlapped each other and formed a "quasi-double layer" over the mica surface. These AFM images proved the existence of a monolayer of protein A molecules at low concentrations and a "quasi-double layer" with occasional protrusions at high concentrations, which were consistent with the adsorption mode observed in the force-distance curves. PMID:9449346

  18. 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.

  19. Adsorbate Diffusion on Transition Metal Nanoparticles

    DTIC Science & Technology

    2015-01-01

    different sizes and shapes using density functional theory calculations. We show that nanoparticles bind adsorbates more strongly than the...structure theoretical methods, a quantitative study with accurate density functional theory (DFT) calculations is still missing. Here, we perform a...functional theory . The projector augmented wave (PAW) potentials29,30 were used for electron- ion interactions and the generalized gradient approximation

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

    PubMed

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

    2017-01-01

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

  1. 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.

  2. 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.

  3. Desorption of isopropyl alcohol from adsorbent with non-thermal plasma.

    PubMed

    Shiau, Chen Han; Pan, Kuan Lun; Yu, Sheng Jen; Yan, Shaw Yi; Chang, Moo Been

    2017-09-01

    Effective desorption of isopropyl alcohol (IPA) from adsorbents with non-thermal plasma is developed. In this system, IPA is effectively adsorbed with activated carbon while dielectric barrier discharge is applied to replace the conventional thermal desorption process to achieve good desorption efficiency, making the treatment equipment smaller in size. Various adsorbents including molecular sieves and activated carbon are evaluated for IPA adsorption capacity. The results indicate that BAC has the highest IPA adsorption capacity (280.31 mg IPA/g) under the operating conditions of room temperature, IPA of 400 ppm, and residence time of 0.283 s among 5 adsorbents tested. For the plasma desorption process, the IPA selectivity of 89% is achieved with BAC as N 2 is used as desorbing gas. In addition, as air or O 2 is used as desorbing gas, the IPA desorption concentration is reduced, because air and O 2 plasmas generate active species to oxidize IPA to form acetone, CO 2 , and even CO. Furthermore, the results of the durability test indicate that the amount of IPA desorbed increases with increasing desorption times and plasma desorption process has a higher energy efficiency if compared with thermal desorption. Overall, this study indicates that non-thermal plasma is a viable process for removing VOCs to regenerate adsorbent.

  4. 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

  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. Effect of adsorbed/intercalated anionic dyes into the mechanical properties of PVA: layered zinc hydroxide nitrate nanocomposites.

    PubMed

    Marangoni, Rafael; Mikowski, Alexandre; Wypych, Fernando

    2010-11-15

    Zinc hydroxide nitrate (ZHN) was adsorbed with anions of blue dyes (Chicago sky blue, CSB; Evans blue, EB; and Niagara blue, NB) and intercalated with anions of orange dyes (Orange G, OG; Orange II, OII; methyl orange, MO). Transparent, homogeneous and colored nanocomposite films were obtained by casting after dispersing the pigments (dye-intercalated/adsorbed into LHSs) into commercial poly(vinyl alcohol) (PVA). The films were characterized by XRD, UV-Vis spectroscopy, and mechanical testing. The mechanical properties of the PVA compounded with the dye-intercalated/adsorbed ZHN were evaluated, and reasonable increases in Young's modulus and ultimate tensile strength were observed, depending on the amount and choice of layered filler. These results demonstrate the possibility of using a new class of layered hydroxide salts intercalated and adsorbed with anionic dyes to prepare multifunctional polymer nanocomposite materials. Copyright © 2010 Elsevier Inc. All rights reserved.

  7. 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.

  8. Performance evaluation of oxygen adsorbents using negative corona discharge-ion mobility spectrometry.

    PubMed

    Azadkish, Kamal; Jafari, Mohammad T; Ghaziaskar, Hassan S

    2017-02-08

    Trace amounts of oxygen was determined using negative corona discharge as an ionization source for ion mobility spectrometry. A point-in-cylinder geometry with novel design was used to establish the corona discharge without interferences of negative ions such as NO X - . The desirable background spectrum shows only electrons peak, providing the instrument capable of trace analysis of oxygen in gaseous samples. The limit of detection and linear dynamic range with high coefficient of determination (r 2  = 0.9997), were obtained for oxygen as 8.5 and 28-14204 ppm, respectively. The relative standard deviations of the method for intraday and interday were obtained 4 and 11%, respectively. The satisfactory results revealed the ability of the negative corona discharge ion mobility spectrometry for investigating the performance of synthesized oxygen adsorbents in nitrogen streams. Two oxygen scavengers of MnO and Cu powder were prepared and the optimum temperature of the reactor containing MnO and Cu powder were obtained as 180 and 230 °C, respectively. Due to higher lifetime of copper powder, it was selected as the oxygen scavenger and some parameters such as: the type of adsorbent support, the size of adsorbent particles, and the amount of copper were studied for preparation of more efficient oxygen adsorbent. Copyright © 2016 Elsevier B.V. All rights reserved.

  9. 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...

  10. Gas storage using fullerene based adsorbents

    NASA Technical Reports Server (NTRS)

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

  11. Green Adsorbents for Wastewaters: A Critical Review

    PubMed Central

    Kyzas, George Z.; Kostoglou, Margaritis

    2014-01-01

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

  12. Simulations of noble gases adsorbed on graphene

    NASA Astrophysics Data System (ADS)

    Maiga, Sidi; Gatica, Silvina

    2014-03-01

    We present results of Grand Canonical Monte Carlo simulations of adsorption of Kr, Ar and Xe on a suspended graphene sheet. We compute the adsorbate-adsorbate interaction by a Lennard-Jones potential. We adopt a hybrid model for the graphene-adsorbate force; in the hybrid model, the potential interaction with the nearest carbon atoms (within a distance rnn) is computed with an atomistic pair potential Ua; for the atoms at r>rnn, we compute the interaction energy as a continuous integration over a carbon uniform sheet with the density of graphene. For the atomistic potential Ua, we assume the anisotropic LJ potential adapted from the graphite-He interaction proposed by Cole et.al. This interaction includes the anisotropy of the C atoms on graphene, which originates in the anisotropic π-bonds. The adsorption isotherms, energy and structure of the layer are obtained and compared with experimental results. We also compare with the adsorption on graphite and carbon nanotubes. This research was supported by NSF/PRDM (Howard University) and NSF (DMR 1006010).

  13. 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.

  14. Nuclear dna amounts in angiosperms.

    PubMed

    Bennett, M D; Smith, J B

    1976-05-27

    The number of angiosperm species for which nuclear DNA amount estimates have been made has nearly trebled since the last collected lists of such values were published, and therefore, publication of a more comprehensive list is over due. This paper lists absolute nuclear DNA amounts for 753 angiosperm species. The dats were assembled primarily for reference purposes, and so the species are listed in alphabetical order, as this was felt to be more helpful to cyto- and biochemists whom, it is anticipated, will be among its major users. The paper also reviews aspects of the history, nomenclature, methods, accuracy and problems of nuclear DNA estimation in angiosperms. No attempt is made to reconsider those aspects of nuclear DNA estimation which have been fully revised previously, although the bibliography of such aspects is given. Instead, the paper is intended as a source of basic information regarding the terminology, practice and limitations of nuclear DNA estimation, especially by Feulgen microdensitometry, as currently practiced.

  15. Structural properties of atactic polystyrene adsorbed onto solid surfaces.

    PubMed

    Tatek, Yergou B; Tsige, Mesfin

    2011-11-07

    In the present work, we are studying the local conformation of chains in a thin film of polystyrene adsorbed on a solid substrate by using atomistically detailed simulations. The simulations are carried out by using the readily available and massively parallel molecular dynamics code known as LAMMPS. In particular, a special emphasis is given to the density and orientation of side chains (which consist of phenyl groups and methylene units) at solid/polymer and polymer/vacuum interfaces. Three types of substrates were used in our study: α-quartz, graphite, and amorphous silica. Our investigation was restricted to atactic polystyrene. Our results show that the density and structural properties of side chains depend on the type of surface. An excess of phenyl rings is observed near the α-quartz substrate while the film adsorbed on graphite is depleted in C(6)H(5). Moreover, the orientation of the rings and methylene units on the substrate/film interface show a strong dependence on the type of the substrate, while the rings at the film/vacuum interface show a marked tendency to point outward, away from the film. The results we obtained are in a large part in good agreement with previous experimental and simulation results.

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

    SciTech Connect

    Saito, Tomonori; Brown, S.; Das, Sadananda

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

  17. Removing ammonium from water and wastewater using cost-effective adsorbents: A review.

    PubMed

    Huang, Jianyin; Kankanamge, Nadeeka Rathnayake; Chow, Christopher; Welsh, David T; Li, Tianling; Teasdale, Peter R

    2018-01-01

    Ammonium is an important nutrient in primary production; however, high ammonium loads can cause eutrophication of natural waterways, contributing to undesirable changes in water quality and ecosystem structure. While ammonium pollution comes from diffuse agricultural sources, making control difficult, industrial or municipal point sources such as wastewater treatment plants also contribute significantly to overall ammonium pollution. These latter sources can be targeted more readily to control ammonium release into water systems. To assist policy makers and researchers in understanding the diversity of treatment options and the best option for their circumstance, this paper produces a comprehensive review of existing treatment options for ammonium removal with a particular focus on those technologies which offer the highest rates of removal and cost-effectiveness. Ion exchange and adsorption material methods are simple to apply, cost-effective, environmentally friendly technologies which are quite efficient at removing ammonium from treated water. The review presents a list of adsorbents from the literature, their adsorption capacities and other parameters needed for ammonium removal. Further, the preparation of adsorbents with high ammonium removal capacities and new adsorbents is discussed in the context of their relative cost, removal efficiencies, and limitations. Efficient, cost-effective, and environmental friendly adsorbents for the removal of ammonium on a large scale for commercial or water treatment plants are provided. In addition, future perspectives on removing ammonium using adsorbents are presented. Copyright © 2017. Published by Elsevier B.V.

  18. 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

  19. Nanoporous Boron Nitride as Exceptionally Thermally Stable Adsorbent: Role in Efficient Separation of Light Hydrocarbons.

    PubMed

    Saha, Dipendu; Orkoulas, Gerassimos; Yohannan, Samuel; Ho, Hoi Chun; Cakmak, Ercan; Chen, Jihua; Ozcan, Soydan

    2017-04-26

    In this work, nanoporous boron nitride sample was synthesized with a Brunauer-Emmett-Teller (BET) surface area of 1360 m 2 /g and particle size 5-7 μm. The boron nitride was characterized with X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), and electron microscopy (TEM and SEM). Thermogravimetric analysis (TGA) under nitrogen and air and subsequent analysis with XPS and XRD suggested that its structure is stable in air up to 800 °C and in nitrogen up to 1050 °C, which is higher than most of the common adsorbents reported so far. Nitrogen and hydrocarbon adsorption at 298 K and pressure up to 1 bar suggested that all hydrocarbon adsorption amounts were higher than that of nitrogen and the adsorbed amount of hydrocarbon increases with an increase in its molecular weight. The kinetics of adsorption data suggested that adsorption becomes slower with the increase in molecular weight of hydrocarbons. The equilibrium data suggested that that boron nitride is selective to paraffins in a paraffin-olefin mixture and hence may act as an "olefin generator". The ideal adsorbed solution theory (IAST)-based selectivity for CH 4 /N 2 , C 2 H 6 /CH 4 , and C 3 H 8 /C 3 H 6 was very high and probably higher than the majority of adsorbents reported in the literature. IAST-based calculations were also employed to simulate the binary mixture adsorption data for the gas pairs of CH 4 /N 2 , C 2 H 6 /CH 4 , C 2 H 6 /C 2 H 4 , and C 3 H 8 /C 3 H 6 . Finally, a simple mathematical model was employed to simulate the breakthrough behavior of the above-mentioned four gas pairs in a dynamic column experiment. The overall results suggest that nanoporous boron nitride can be used as a potential adsorbent for light hydrocarbon separation.

  20. 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. Copyright © 2015 Elsevier Ltd. All rights reserved.

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

    PubMed

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

    2018-01-15

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

  2. Determination of Adsorption Equations for Chloro Derivatives of Aniline on Halloysite Adsorbents Using Inverse Liquid Chromatography.

    PubMed

    Słomkiewicz, Piotr M; Szczepanik, Beata; Garnuszek, Magdalena; Rogala, Paweł; Witkiewicz, Zygfryd

    2017-11-01

    Chloro derivatives of aniline are commonly used in the production of dyes, pharmaceuticals, and agricultural agents. They are toxic compounds with a large accumulation ability and low natural biodegradability. Halloysite is known as an efficient adsorbent of toxic compounds, such as phenols or herbicides, from wastewater. Inverse LC was applied to measure the adsorption of aniline and 2-chloroaniline (2-CA), 3-chloroaniline (3-CA), and 4-chloroaniline (4-CA) on halloysite adsorbents. A peak division (PD) method was used to determine a Langmuir equation in accordance with the adsorption measurement results. The values of adsorption equilibrium constants and enthalpy were determined and compared by breakthrough curve and PD methods. The physical sense of the calculated adsorption enthalpy values was checked by applying Boudart's entropy criteria. Of note, adsorption enthalpy values for halloysite adsorbents decreased in the following order: aniline > 4-CA > 2-CA > 3-CA.

  3. Binary chromatographic data and estimation of adsorbent porosities. [data for system n-heptane/n-pentane

    NASA Technical Reports Server (NTRS)

    Meisch, A. J.

    1972-01-01

    Data for the system n-pentane/n-heptane on porous Chromosorb-102 adsorbent were obtained at 150, 175, and 200 C for mixtures containing zero to 100% n-pentane by weight. Prior results showing limitations on superposition of pure component data to predict multicomponent chromatograms were verified. The thermodynamic parameter MR0 was found to be a linear function of sample composition. A nonporous adsorbent failed to separate the system because of large input sample dispersions. A proposed automated data processing scheme involving magnetic tape recording of the detector signals and processing by a minicomputer was rejected because of resolution limitations of the available a/d converters. Preliminary data on porosity and pore size distributions of the adsorbents were obtained.

  4. The Uranium from Seawater Program at the Pacific Northwest National Laboratory: Overview of Marine Testing, Adsorbent Characterization, Adsorbent Durability, Adsorbent Toxicity, and Deployment Studies

    SciTech Connect

    Gill, Gary A.; Kuo, Li-Jung; Janke, Chris J.

    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« less

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

    PubMed Central

    2017-01-01

    Calcium alginate beads doped with hydrazine sulphate-treated red mud are investigated as adsorbent for extracting lead ions from water using batch methods of extraction. Different extraction conditions are optimised for maximum lead extraction. Substantial amount of lead is removed, and the adsorption ability is found to be 138.6 mg/g. Surface characterization using FTIR, EDX, and FESEM confirms that lead is “onto” the surface of the adsorbent. Thermodynamic parameters, adsorption isotherms, and kinetics of adsorption are analysed. Adsorption is “physisorption” in nature and spontaneous. The adsorbent developed can be regenerated using 0.1 M HCl. Thus regenerated adsorbent can be used as the adsorbent for further removal of lead at least 10 times, and this enables the complete removal of lead from water by repetitive use of the regenerated adsorbent. The beads facilitate the easy filtration. The methodology developed is successfully applied for removing lead from industrial waste waters. PMID:29527385

  6. Adsorbent materials from paper industry waste materials and their use in Cu(II) removal from water.

    PubMed

    Méndez, A; Barriga, S; Fidalgo, J M; Gascó, G

    2009-06-15

    This paper deals with the removal of Cu(2+) from water using adsorbent materials prepared from paper industry waste materials (one de-inking paper sludge and other sludge from virgin pulp mill). Experimental results showed that de-inking paper sludge leads to mesoporous materials (V(mic)/V(T)=0.13 and 0.14), whereas the sludge from virgin pulp mill produces high microporous adsorbents (V(mic)/V(T)=0.39 and 0.41). Adsorbent materials were then used for Cu(2+) removal from water at acid pH. During water treatment, heavy metals lixiviation from adsorbent materials was not produced. However, important Ca and Mg leaching was observed. Final pH significantly increases after treatment of water with adsorbent materials probably due to their elevated CaCO(3) content. In general, highest Cu(2+) removal was obtained using adsorbent materials from de-inking paper sludge. This result could be due to their higher content in oxygenated surface groups, high average pore diameter, elevated superficial charge density, high CaCO(3) amount and high Ca and Mg exchange content.

  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. Selective removal of organochlorine pesticides (OCPs) from aqueous solution by triolein-embedded composite adsorbent.

    PubMed

    Ru, J; Liu, H J; Qu, J H; Wang, A M; Dai, R H; Wang, Z J

    2007-01-01

    A novel composite adsorbent (CA-T) was used for the selective removal of organochlorine pesticides (OCPs) from aqueous solution. The adsorbent was composed of the supporting activated carbon and the surrounding triolein-embedded cellulose acetate membrane. Scanning electron microscopy (SEM), N2 adsorption isotherms and fluorescence methods were used to characterize the physicochemical properties of CA-T. Triolein was perfectly embedded in the cellulose acetate membrane and deposited on the surface of activated carbon. The adsorbent was stable in water and no triolein leakage was detected during the test periods. Some organochlorine pesticides (OCPs), such as dieldrin, endrin, aldrin, and heptachlor epoxide, were used as model contaminants and removed by CA-T in laboratory batch experiments. The adsorption isotherm followed the Freundlich equation and the kinetic data fitted well to the pseudo-second-order reaction model. Results also indicated that CA-T appeared to be a promising adsorbent with good selectivity and satisfactory removal rate for lipophilic OCPs from aqueous solutions when present in trace amounts. The adsorption rate and removal efficiency for lipophilic OCPs were positively related to their octanol-water partition coefficients (log K(ow)). Lower residual concentrations of OCPs were achieved when compared to granular activated carbon (GAC).

  9. Toluene and acetaldehyde removal from air on to graphene-based adsorbents with microsized pores.

    PubMed

    Kim, Ji Min; Kim, Ji Hoon; Lee, Chang Yeon; Jerng, Dong Wook; Ahn, Ho Seon

    2018-02-15

    Volatile organic compound (VOC) gases can cause harm to the human body with exposure over the long term even at very low concentrations (ppmv levels); thus, effective absorbents for VOC gas removal are an important issue. In this study, accordingly, graphene-based adsorbents with microsized pores were used as adsorbents to remove toluene and acetaldehyde gases at low concentrations (30ppm). Sufficient amounts of the adsorbents were prepared for use on filters and were loaded uniformly at 0.1-0.5g on a 50×50mm 2 area, to evaluate their adsorption features with low gas concentrations. The morphology and chemical composition of the adsorbents were characterized using scanning electron microscopy, N 2 adsorption-desorption isotherms, X-ray photoelectron spectroscopy, and Raman spectroscopy. Microwave irradiation and heat treatment near 800°C under KOH activation resulted in enlargement of the pristine graphene surface and its specific surface area; maximum volume capacities of 3510m 3 /g and 630m 3 /g were observed for toluene and acetaldehyde gas. The high removal efficiency for toluene (98%) versus acetaldehyde (30%) gas was attributed to π-π interactions between the pristine graphene surface and toluene molecules. Copyright © 2017 Elsevier B.V. All rights reserved.

  10. 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.

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

    PubMed

    Oliveira, Luiz C A; Gonçalves, Maraísa; Oliveira, Diana Q L; Guerreiro, Mário C; Guilherme, Luiz R G; Dallago, Rogério M

    2007-03-06

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

  12. A potential low cost adsorbent for the removal of cationic dyes from aqueous solutions

    NASA Astrophysics Data System (ADS)

    Uddin, Md. Tamez; Rahman, Md. Arifur; Rukanuzzaman, Md.; Islam, Md. Akhtarul

    2017-10-01

    This study was aimed at using mango leaf powder (MLP) as a potential adsorbent for the removal of methylene blue (MB) from aqueous solutions. Characterization of the adsorbent was carried out with scanning electron microscopy, Fourier transform infrared spectroscopy, and nitrogen adsorption-desorption analysis. The pH at the point of zero charge of the adsorbent was determined by titration method and was found a value to be 5.6 ± 0.2. Batch studies were performed to evaluate the influence of various experimental parameters like initial solution pH, contact time, initial concentration of dye and adsorbent dosage on the removal of MB. An adsorption-desorption study was carried out resulting the mechanism of adsorption was carried out by electrostatic force of attraction. The adsorption equilibrium time required for the adsorption of MB on MLP was almost 2 h and 85 ± 5% of the total amount of dye uptake was found to occur in the first rapid phase (30 min). The Langmuir and Freundlich isotherm models were used for modeling the adsorption equilibrium. The experimental equilibrium data could be well interpreted by Langmuir isotherm with maximum adsorption capacity of 156 mg/g. To state the sorption kinetics, the fits of pseudo-first-order and pseudo-second-order kinetic models were investigated. It was obtained that the adsorption process followed the pseudo-second-order rate kinetics. The above findings suggest that MLP can be effectively used for decontamination of dye containing wastewater.

  13. 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.

  14. The molecular mechanism of mediation of adsorbed serum proteins to endothelial cells adhesion and growth on biomaterials.

    PubMed

    Yang, Dayun; Lü, Xiaoying; Hong, Ying; Xi, Tingfei; Zhang, Deyuan

    2013-07-01

    To explore molecular mechanism of mediation of adsorbed proteins to cell adhesion and growth on biomaterials, this study examined endothelial cell adhesion, morphology and viability on bare and titanium nitride (TiN) coated nickel titanium (NiTi) alloys and chitosan film firstly, and then identified the type and amount of serum proteins adsorbed on the three surfaces by proteomic technology. Subsequently, the mediation role of the identified proteins to cell adhesion and growth was investigated with bioinformatics analyses, and further confirmed by a series of cellular and molecular biological experiments. Results showed that the type and amount of adsorbed serum proteins associated with cell adhesion and growth was obviously higher on the alloys than on the chitosan film, and these proteins mediated endothelial cell adhesion and growth on the alloys via four ways. First, proteins such as adiponectin in the adsorbed protein layer bound with cell surface receptors to generate signal transduction, which activated cell surface integrins through increasing intracellular calcium level. Another way, thrombospondin 1 in the adsorbed protein layer promoted TGF-β signaling pathway activation and enhanced integrins expression. The third, RGD sequence containing proteins such as fibronectin 1, vitronectin and thrombospondin 1 in the adsorbed protein layer bound with activated integrins to activate focal adhesion pathway, increased focal adhesion formation and actin cytoskeleton organization and mediated cell adhesion and spreading. In addition, the activated focal adhesion pathway promoted the expression of cell growth related genes and resulted in cell proliferation. The fourth route, coagulation factor II (F2) and fibronectin 1 in the adsorbed protein layer bound with cell surface F2 receptor and integrin, activated regulation of actin cytoskeleton pathway and regulated actin cytoskeleton organization. Copyright © 2013 Elsevier Ltd. All rights reserved.

  15. 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.

  16. 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.

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

    PubMed

    Inoue, Kenichiro; Kawamoto, Katsuya

    2005-08-01

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

  18. 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%.

  19. Natural adsorbents of dyes from aqueous solution

    NASA Astrophysics Data System (ADS)

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

    2017-04-01

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

  20. Structure of Irreversibly Adsorbed Star Polymers

    NASA Astrophysics Data System (ADS)

    Akgun, Bulent; Aykan, Meryem Seyma; Canavar, Seda; Satija, Sushil K.; Uhrig, David; Hong, Kunlun

    Formation of irreversibly adsorbed polymer chains on solid substrates have a huge impact on the wetting, glass transition, aging and polymer chain mobility in thin films. In recent years there has been many reports on the formation, kinetics and dynamics of these layers formed by linear homopolymers. Recent studies showed that by varying the number of polymer arms and arm molecular weight one can tune the glass transition temperature of thin polymer films. Using polymer architecture as a tool, the behavior of thin films can be tuned between the behavior of linear chains and soft colloids. We have studied the effect of polymer chain architecture on the structure of dead layer using X-ray reflectivity (XR) and atomic force microscopy. Layer thicknesses and densities of flattened and loosely adsorbed chains has been measured for linear, 4-arm, and 8-arm star polymers with identical total molecular weight as a function of substrate surface energy, annealing temperature and annealing time. Star polymers have been synthesized using anionic polymerization. XR measurements showed that 8-arm star PS molecules form the densest and the thickest dead layers among these three molecules.

  1. Electronic properties of NH{sub 4}-adsorbed graphene nanoribbon as a promising candidate for a gas sensor

    SciTech Connect

    Harada, Naoki, E-mail: harada.naoki@jp.fujitsu.com; Sato, Shintaro

    2016-05-15

    The electronic properties of NH{sub 4}-adsorbed N = 7 armchair graphene nanoribbons (AGNRs) were theoretically investigated using self-consistent atomistic simulations to explore the feasibility of AGNRs as a gas sensing material. Whereas a pristine AGNR has a finite band gap and is an intrinsic semiconductor, an NH{sub 4}-adsorbed AGNR exhibits heavily doped n-type properties similar to a graphene sheet with the molecules adsorbed. The electric characteristics of a back-gated AGNR gas sensor were also simulated and the drain current changed exponentially with increasing number of adsorbed molecules. We may conclude that an AGNR is promising as a highly sensitive gas-sensingmore » material with large outputs.« less

  2. 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

  3. Characterization of natural organic matter adsorption in granular activated carbon adsorbers.

    PubMed

    Velten, Silvana; Knappe, Detlef R U; Traber, Jacqueline; Kaiser, Hans-Peter; von Gunten, Urs; Boller, Markus; Meylan, Sébastien

    2011-07-01

    The removal of natural organic matter (NOM) from lake water was studied in two pilot-scale adsorbers containing granular activated carbon (GAC) with different physical properties. To study the adsorption behavior of individual NOM fractions as a function of time and adsorber depth, NOM was fractionated by size exclusion chromatography (SEC) into biopolymers, humics, building blocks, and low molecular weight (LMW) organics, and NOM fractions were quantified by both ultraviolet and organic carbon detectors. High molecular weight biopolymers were not retained in the two adsorbers. In contrast, humic substances, building blocks and LMW organics were initially well and irreversibly removed, and their effluent concentrations increased gradually in the outlet of the adsorbers until a pseudo-steady state concentration was reached. Poor removal of biopolymers was likely a result of their comparatively large size that prevented access to the internal pore structure of the GACs. In both GAC adsorbers, adsorbability of the remaining NOM fractions, compared on the basis of partition coefficients, increased with decreasing molecular size, suggesting that increasingly larger portions of the internal GAC surface area could be accessed as the size of NOM decreased. Overall DOC uptake at pseudo-steady state differed between the two tested GACs (18.9 and 28.6 g-C/kg GAC), and the percent difference in DOC uptake closely matched the percent difference in the volume of pores with widths in the 1-50 nm range that was measured for the two fresh GACs. Despite the differences in NOM uptake capacity, individual NOM fractions were removed in similar proportions by the two GACs. Copyright © 2011 Elsevier Ltd. All rights reserved.

  4. 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.

  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. Verification of chloride adsorption effect of mortar with salt adsorbent

    NASA Astrophysics Data System (ADS)

    Hoshina, T.; Nakajima, N.; Sudo, H.; Date, S.

    2017-11-01

    In order to investigate the chloride adsorption effect of mortar mixed with chloride adsorbent, electrophoresis test using mortar specimen and immersion dry repeated test were conducted to evaluate chloride adsorption effect. As a result, it was confirmed that soluble salt content that causes corrosion of rebar in the specimen was reduced by the chloride adsorbent and corrosion inhibiting effect of the rebar was also obtained. It was also confirmed that by increasing dosage of the chloride adsorbent, the chloride adsorbing effect becomes larger as well..

  7. 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. Copyright © 2012 Elsevier Ltd. All rights reserved.

  8. Rapid detection of trace amounts of surfactants using nanoparticles in fluorometric assays

    NASA Astrophysics Data System (ADS)

    Härmä, Harri; Laakso, Susana; Pihlasalo, Sari; Hänninen, Pekka; Faure, Bertrand; Rana, Subhasis; Bergström, Lennart

    2010-01-01

    Rapid microtiter assays that utilize the time-resolved fluorescence resonance energy transfer or quenching of dye-labeled proteins adsorbed onto the surfaces of polystyrene or maghemite nanoparticles have been developed for the detection and quantification of trace amounts of surfactants at concentrations down to 10 nM.Rapid microtiter assays that utilize the time-resolved fluorescence resonance energy transfer or quenching of dye-labeled proteins adsorbed onto the surfaces of polystyrene or maghemite nanoparticles have been developed for the detection and quantification of trace amounts of surfactants at concentrations down to 10 nM. Electronic supplementary information (ESI) available: Experimental details and Fig. S1 and S2. See DOI: 10.1039/b9nr00172g

  9. Differences between tethered polyelectrolyte chains adsorbed onto bare mica and hydrophobically modified mica, comparison with theory.

    NASA Astrophysics Data System (ADS)

    Balastre, Marc; Tamashiro, Mario N.; Hernandez, Ernesto; Pincus, Philip; Tirrell, Matthew

    2001-03-01

    End-grafted polymers generated from the adsorption of asymmetric diblock copolymers on solid surface play an important role in many areas of science and technology. While the small insoluble block acts as an anchor, the charged soluble block confers useful properties to the surface. This study looks at tethered layers of poly(styrene sulfonate)/poly(t-butyl styrene) (PtBS-PSS) adsorbed on both mica (hydrophilic) and octadecyltriethoxysilane (OTE) modified mica (hydrophobic). Normal compressing forces at two different constant grafting densities (bare and modified mica) were measured with the surface force apparatus and compared with theoretical prediction. The effect of salt concentration (Cs) upon the thickness of the self-assembled layers (Lo) was measured in each case. For adsorption of diblock copolymers onto OTE the resulting scaling relationship is much closer to the brush theory, Lo Cs-1/3. This result suggests that the adsorbed amount on mica is not high enough to form a brush.

  10. Morin Flavonoid Adsorbed on Mesoporous Silica, a Novel Antioxidant Nanomaterial

    PubMed Central

    Arriagada, Francisco; Correa, Olosmira; Günther, Germán; Nonell, Santi; Mura, Francisco; Olea-Azar, Claudio

    2016-01-01

    Morin (2´,3, 4´,5,7-pentahydroxyflavone) is a flavonoid with several beneficial health effects. However, its poor water solubility and it sensitivity to several environmental factors avoid its use in applications like pharmaceutical and cosmetic. In this work, we synthetized morin-modified mesoporous silica nanoparticles (AMSNPs-MOR) as useful material to be used as potential nanoantioxidant. To achieve this, we characterized its adsorption kinetics, isotherm and the antioxidant capacity as hydroxyl radical (HO•) scavenger and singlet oxygen (1O2) quencher. The experimental data could be well fitted with Langmuir, Freundlich and Temkin isotherm models, besides the pseudo-second order kinetics model. The total quenching rate constant obtained for singlet oxygen deactivation by AMSNPs-MOR was one order of magnitude lower than the morin rate constant reported previously in neat solvents and lipid membranes. The AMSNPs-MOR have good antioxidant properties by itself and exhibit a synergic effect with morin on the antioxidant property against hydroxyl radical. This effect, in the range of concentrations studied, was increased when the amount of morin adsorbed increased. PMID:27812111

  11. Adsorption of aromatic compounds by carbonaceous adsorbents: a comparative study on granular activated carbon, activated carbon fiber, and carbon nanotubes.

    PubMed

    Zhang, Shujuan; Shao, Ting; Kose, H Selcen; Karanfil, Tanju

    2010-08-15

    Adsorption of three aromatic organic compounds (AOCs) by four types of carbonaceous adsorbents [a granular activated carbon (HD4000), an activated carbon fiber (ACF10), two single-walled carbon nanotubes (SWNT, SWNT-HT), and a multiwalled carbon nanotube (MWNT)] with different structural characteristics but similar surface polarities was examined in aqueous solutions. Isotherm results demonstrated the importance of molecular sieving and micropore effects in the adsorption of AOCs by carbonaceous porous adsorbents. In the absence of the molecular sieving effect, a linear relationship was found between the adsorption capacities of AOCs and the surface areas of adsorbents, independent of the type of adsorbent. On the other hand, the pore volume occupancies of the adsorbents followed the order of ACF10 > HD4000 > SWNT > MWNT, indicating that the availability of adsorption site was related to the pore size distributions of the adsorbents. ACF10 and HD4000 with higher microporous volumes exhibited higher adsorption affinities to low molecular weight AOCs than SWNT and MWNT with higher mesopore and macropore volumes. Due to their larger pore sizes, SWNTs and MWNTs are expected to be more efficient in adsorption of large size molecules. Removal of surface oxygen-containing functional groups from the SWNT enhanced adsorption of AOCs.

  12. 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.

  13. Headgroup effects of template monolayers on the adsorption behavior and conformation of glucose oxidase adsorbed at air/liquid interfaces.

    PubMed

    Wang, Ke-Hsuan; Syu, Mei-Jywan; Chang, Chien-Hsiang; Lee, Yuh-Lang

    2011-06-21

    Stearic acid (SA) and octadecylamine (ODA) monolayers at the air/liquid interface were used as template layers to adsorb glucose oxidase (GOx) from aqueous solution. The effect of the template monolayers on the adsorption behavior of GOx was studied in terms of the variation of surface pressure, the evolution of surface morphology observed by BAM and AFM, and the conformation of adsorbed GOx. The results show that the presence of a template monolayer can enhance the adsorption rate of GOx; furthermore, ODA has a higher ability, compared to SA, to adsorb GOx, which is attributed to the electrostatic attractive interaction between ODA and GOx. For adsorption performed on a bare surface or on an SA monolayer, the surface pressure approaches an equilibrium value (ca. 8 mN/m) after 2 to 3 h of adsorption and remains nearly constant in the following adsorption process. For the adsorption on an ODA monolayer, the surface pressure will increase further 1 to 2 h after approaching the first equilibrium pressure, which is termed the second adsorption stage. The measurement of circular dichroism (CD) spectroscopy indicates that the Langmuir-Blodgett films of adsorbed GOx transferred at the first equilibrium state (π = 8 mN/m) have mainly a β-sheet conformation, which is independent of the type of template monolayers. However, the ODA/GOx LB film transferred at the second adsorption stage has mainly an α-helix conformation. It is concluded that the specific interaction between ODA and GOx not only leads to a higher adsorption rate and adsorbed amount of GOx but also induces a conformation change in adsorbed GOx from β-sheet to α-helix. The present results indicate that is possible to control the conformation of adsorbed protein by selecting the appropriate template monolayer. © 2011 American Chemical Society

  14. Internal Reflection Spectra of Surface Compounds and Adsorbed Molecules

    NASA Astrophysics Data System (ADS)

    Zolotarev, V. M.; Lygin, V. I.; Tarasevich, B. N.

    1981-01-01

    The application of attenuated total reflection (ATR) spectroscopy in surface studies of inorganic adsorbents and catalysts, polymers, and optically transparent electrodes is discussed. The basic principles of ATR spectroscopy as applied to surface phenomena are considered, with special reference to thin films, industrial adsorbents and catalysts, and polymer degradation processes. 276 references.

  15. Analysis and comparison of inertinite-derived adsorbent with conventional adsorbents.

    PubMed

    Gangupomu, Roja Haritha; Kositkanawuth, Ketwalee; Sattler, Melanie L; Ramirez, David; Dennis, Brian H; MacDonnell, Frederick M; Billo, Richard; Priest, John W

    2012-05-01

    To increase U.S. petroleum energy-independence, the University of Texas at Arlington (UT Arlington) has developed a coal liquefaction process that uses a hydrogenated solvent and a proprietary catalyst to convert lignite coal to crude oil. This paper reports on part of the environmental evaluation of the liquefaction process: the evaluation of the solid residual from liquefying the coal, called inertinite, as a potential adsorbent for air and water purification. Inertinite samples derived from Arkansas and Texas lignite coals were used as test samples. In the activated carbon creation process, inertinite samples were heated in a tube furnace (Lindberg, Type 55035, Arlington, UT) at temperatures ranging between 300 and 850 degrees C for time spans of 60, 90, and 120 min, using steam and carbon dioxide as oxidizing gases. Activated inertinite samples were then characterized by ultra-high-purity nitrogen adsorption isotherms at 77 K using a high-speed surface area and pore size analyzer (Quantachrome, Nova 2200e, Kingsville, TX). Surface area and total pore volume were determined using the Brunauer Emmet, and Teller method, for the inertinite samples, as well as for four commercially available activated carbons (gas-phase adsorbents Calgon Fluepac-B and BPL 4 x 6; liquid-phase adsorbents Filtrasorb 200 and Carbsorb 30). In addition, adsorption isotherms were developed for inertinite and the two commercially available gas-phase carbons, using methyl ethyl ketone (MEK) as an example compound. Adsorption capacity was measured gravimetrically with a symmetric vapor sorption analyzer (VTI, Inc., Model SGA-100, Kingsville, TX). Also, liquid-phase adsorption experiments were conducted using methyl orange as an example organic compound. The study showed that using inertinite from coal can be beneficially reused as an adsorbent for air or water pollution control, although its surface area and adsorption capacity are not as high as those for commercially available activated

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

  17. 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. Copyright © 2015. Published by Elsevier B.V.

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

    PubMed

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

    2005-09-08

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

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

    NASA Astrophysics Data System (ADS)

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

    2017-05-01

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

  20. Kondo effect in single cobalt phthalocyanine molecules adsorbed on Au(111) monoatomic steps

    NASA Astrophysics Data System (ADS)

    Zhao, Aidi; Hu, Zhenpeng; Wang, Bing; Xiao, Xudong; Yang, Jinlong; Hou, J. G.

    2008-06-01

    The Kondo effect in single dehydrogenated cobalt phthalocyanine (CoPc) molecules adsorbed on Au(111) monoatomic steps was studied with a low temperature scanning tunneling microscope. The CoPc molecules adsorbed on Au(111) monoatomic steps show two typical configurations, which can be dehydrogenated to reveal Kondo effect. Moreover, the Kondo temperatures (TK) measured for different molecules vary in a large range from ~150 to ~550 K, increasing monotonically with decreasing Co-Au distance. A simple model consisting of a single Co 3dz2 orbital and a Au 6s orbital is considered and gives a qualitative explanation to the dependence. The large variation of TK is attributed to the variation of the interaction between the magnetic-active cobalt ion and the Au substrate resulted from different Co-Au distances.

  1. 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

    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 wasmore » 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.« less

  2. 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.

  3. EFFECT OF SIMULATED SULFURIC ACID RAIN ON THE CHEMISTRY OF A SULFATE-ADSORBING FOREST SOIL

    EPA Science Inventory

    Simulated H2SO4 rain (pH 3.0, 3.5, 4.0) or control rain (pH 5.6) was applied for 3.5 yr to large lysimeter boxes containing a sulfate-adsorbing forest soil and either red alder (Alnus rubra) or sugar maple (Acer saccharum) seedlings. After removal of the plants and the litter lay...

  4. 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

  5. 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.

  6. Imaging the wave functions of adsorbed molecules

    PubMed Central

    Lüftner, Daniel; Ules, Thomas; Reinisch, Eva Maria; Koller, Georg; Soubatch, Serguei; Tautz, F. Stefan; Ramsey, Michael G.; Puschnig, Peter

    2014-01-01

    The basis for a quantum-mechanical description of matter is electron wave functions. For atoms and molecules, their spatial distributions and phases are known as orbitals. Although orbitals are very powerful concepts, experimentally only the electron densities and -energy levels are directly observable. Regardless whether orbitals are observed in real space with scanning probe experiments, or in reciprocal space by photoemission, the phase information of the orbital is lost. Here, we show that the experimental momentum maps of angle-resolved photoemission from molecular orbitals can be transformed to real-space orbitals via an iterative procedure which also retrieves the lost phase information. This is demonstrated with images obtained of a number of orbitals of the molecules pentacene (C22H14) and perylene-3,4,9,10-tetracarboxylic dianhydride (C24H8O6), adsorbed on silver, which are in excellent agreement with ab initio calculations. The procedure requires no a priori knowledge of the orbitals and is shown to be simple and robust. PMID:24344291

  7. 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 which...

  8. 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... 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 which...

  9. 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.

  10. 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.

  11. 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.

  12. 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

  13. 197 Au Mössbauer study of the gold species adsorbed on carbon from cyanide solutions

    NASA Astrophysics Data System (ADS)

    Kongolo, K.; Bahr, A.; Friedl, J.; Wagner, F. E.

    1990-04-01

    The gold species present on activated carbon after adsorption from solutions of Au(CN)2 - have been studied by197Au Mössbauer spectroscopy as a function of the pH value of the solution, the loading of the carbon, the coadsorption of polyvalent cations, and the treatment of the samples after adsorption. The gold was found to be adsorbed mainly as Au(CN)2 -. Coadsorbed polyvalent cations (Ca²+, Gd³+) have no influence on the Mössbauer parameters of the adsorbed gold complex. After adsorption from acidic solutions (pH ≲ 4), one finds a substantial amount of adsorbed gold with Mössbauer parameters similar to those of crystalline AuCN. Presumably, this gold is bound in Aux(CN)x+1 oligomers which form during drying. An additional product with Mössbauer parameters close to those of KAu(CN)2Cl2 was observed on dried samples after adsorption at pH 1. A minor gold species with an uncommonly small electric quadrupole splitting was found on wet carbons but disappeared on drying.

  14. 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.

  15. Novel adhesive properties of poly(ethylene-oxide) adsorbed nanolayers

    NASA Astrophysics Data System (ADS)

    Zeng, Wenduo

    Solid-polymer interfaces play crucial roles in the multidisciplinary field of nanotechnology and are the confluence of physics, chemistry, biology, and engineering. There is now growing evidence that polymer chains irreversibly adsorb even onto weakly attractive solid surfaces, forming a nanometer-thick adsorbed polymer layer ("adsorbed polymer nanolayers"). It has also been reported that the adsorbed layers greatly impact on local structures and properties of supported polymer thin films. In this thesis, I aim to clarify adhesive and tribological properties of adsorbed poly(ethylene-oxide) (PEO) nanolayers onto silicon (Si) substrates, which remain unsolved so far. The adsorbed nanolayers were prepared by the established protocol: one has to equilibrate the melt or dense solution against a solid surface; the unadsorbed chains can be then removed by a good solvent, while the adsorbed chains are assumed to maintain the same conformation due to the irreversible freezing through many physical solid-segment contacts. I firstly characterized the formation process and the surface/film structures of the adsorbed nanolayers by using X-ray reflectivity, grazing incidence X-ray diffraction, and atomic force microscopy. Secondly, to compare the surface energy of the adsorbed layers with the bulk, static contact angle measurements with two liquids (water and glycerol) were carried out using a optical contact angle meter equipped with a video camera. Thirdly, I designed and constructed a custom-built adhesion-testing device to quantify the adhesive property. The experimental results provide new insight into the microscopic structure - macroscopic property relationship at the solid-polymer interface.

  16. Thermal properties of adsorbed molecule in external field

    NASA Astrophysics Data System (ADS)

    Devi, Sumana; Vidhani, Bhavna; Prasad, Vinod

    2018-05-01

    Thermodynamic properties such as free energy, internal energy, entropy and specific heat of an adsorbed molecule are systematically investigated in static electric field for four different confinements. The confined potentials taken are suitable for different experimental conditions and are very useful in determining properties of molecules adsorbed under different environments. The time independent Schrödinger equation is solved numerically using accurate 9-point finite difference method. The Energy spectrum thus obtained is used to find thermal properties of the adsorbed molecule. Interesting results are obtained and explained.

  17. [Effects of various adsorbants on coagulation factors (author's transl)].

    PubMed

    Soulier, J P; Prou-Wartelle, O

    1975-01-01

    Adsorption of clotting factors by various adsorbants is studied (tricalcium phosphate, baryum sulfate or carbonate or citrate, calcium oxalate, aluminium hydroxyde and several silicate such as: kaolin, celite, bentonite, attapulgite, beidellite, asbestos). The main properties of each adsorbant are listed as well as several applications such as: selective adsorption of fibrinogen, separation between fibrinogen and factor VIII, separation of factor II from the other components of the prothrombin complex. Activation of factors XII and XI by the various silicates, as well as the activation of factor V by attapulgite are studied. Finally, the action of such adsorbants on the fibrinolytic system is summarized.

  18. 45 CFR 32.8 - Amounts withheld.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ...) of this section, or (ii) An amount equal to 25% of the debtor's disposable pay less the amount(s... first pay day after the employer receives the order. However, if the first pay day is within 10 days after receipt of the order, the employer may begin deductions on the second pay day. (k) An employer may...

  19. 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 loan...

  20. 27 CFR 70.243 - Exempt amount.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... as wages, salary, or other income for each payroll period described in § 70.244 of this part are exempt from levy as follows: (a) If the payroll period is weekly, an amount equal to: (1) The sum of: (i...) If the payroll period is not weekly, the amount exempt from levy shall be an amount which as nearly...

  1. 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 on...

  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 of...

  3. 46 CFR Sec. 2 - Amount of bond.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... Amount of bond. The amount of the bond must be governed by the amount of monies advanced or value of slop chest property entrusted, and shall, at all times, not be less than the value of slop chest property entrusted plus advances of monies for which a satisfactory accounting has not been made. ...

  4. 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

  5. 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.

  6. Tunable magnetism in metal adsorbed fluorinated nanoporous graphene

    DOE PAGES

    Kumar, Pankaj; Sharma, Vinit; Reboredo, Fernando A.; ...

    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 μ B 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 MAEmore » 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. In conclusion, our predictions open a promising way towards controlling the magnetic properties in graphene based spintronic and non-volatile memory devices.« less

  7. 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.

  8. 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.

  9. 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.

  10. Selectivity of β-Sitosterol Imprinted Polymers as Adsorbent

    NASA Astrophysics Data System (ADS)

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

    2018-03-01

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

  11. Atomic scale friction of molecular adsorbates during diffusion.

    PubMed

    Lechner, B A J; de Wijn, A S; Hedgeland, H; Jardine, A P; Hinch, B J; Allison, W; Ellis, J

    2013-05-21

    Experimental observations suggest that molecular adsorbates exhibit a larger friction coefficient than atomic species of comparable mass, yet the origin of this increased friction is not well understood. We present a study of the microscopic origins of friction experienced by molecular adsorbates during surface diffusion. Helium spin-echo measurements of a range of five-membered aromatic molecules, cyclopentadienyl, pyrrole, and thiophene, on a copper(111) surface are compared with molecular dynamics simulations of the respective systems. The adsorbates have different chemical interactions with the surface and differ in bonding geometry, yet the measurements show that the friction is greater than 2 ps(-1) for all these molecules. We demonstrate that the internal and external degrees of freedom of these adsorbate species are a key factor in the underlying microscopic processes and identify the rotation modes as the ones contributing most to the total measured friction coefficient.

  12. Arsenic Adsorption from Water Using Graphene-Based Materials as Adsorbents: a Critical Review

    NASA Astrophysics Data System (ADS)

    Yang, Xuetong; Xia, Ling; Song, Shaoxian

    2017-07-01

    Adsorption is widely applied to remove arsenic from water. This paper reviewed and compared the recent progresses on the arsenic removal by adsorption using two-dimensional and three-dimensional graphene-based materials as adsorbents. Functional graphene sheet achieved the largest As(III) adsorption capacity of 138.79mg/g, while Mg-Al LDH/GO2 showed the largest As(V) adsorption capacity of 183.11mg/g. Parameters including pH, temperature, co-existing ions and loaded metal or metal oxide affected the adsorption process. The adsorption mechanisms of graphene-based materials for As(III) and As(V) could be explained by surface complexation and the electrostatic attraction, respectively. Future works are suggested to focus on regenerating of two-dimensional graphene-based adsorbents and developing the three-dimensional with large specific surface area and better adsorption performance.

  13. The amount effect and marginal value.

    PubMed

    Rachlin, Howard; Arfer, Kodi B; Safin, Vasiliy; Yen, Ming

    2015-07-01

    The amount effect of delay discounting (by which the value of larger reward amounts is discounted by delay at a lower rate than that of smaller amounts) strictly implies that value functions (value as a function of amount) are steeper at greater delays than they are at lesser delays. That is, the amount effect and the difference in value functions at different delays are actually a single empirical finding. Amount effects of delay discounting are typically found with choice experiments. Value functions for immediate rewards have been empirically obtained by direct judgment. (Value functions for delayed rewards have not been previously obtained.) The present experiment obtained value functions for both immediate and delayed rewards by direct judgment and found them to be steeper when the rewards were delayed--hence, finding an amount effect with delay discounting. © Society for the Experimental Analysis of Behavior.

  14. Adsorbed water and thin liquid films on Mars

    NASA Astrophysics Data System (ADS)

    Boxe, C. S.; Hand, K. P.; Nealson, K. H.; Yung, Y. L.; Yen, A. S.; Saiz-Lopez, A.

    2012-07-01

    At present, bulk liquid water on the surface and near-subsurface of Mars does not exist due to the scarcity of condensed- and gas-phase water, pressure and temperature constraints. Given that the nuclei of soil and ice, that is, the soil solid and ice lattice, respectively, are coated with adsorbed and/or thin liquid films of water well below 273 K and the availability of water limits biological activity, we quantify lower and upper limits for the thickness of such adsorbed/water films on the surface of the Martian regolith and for subsurface ice. These limits were calculated based on experimental and theoretical data for pure water ice and water ice containing impurities, where water ice containing impurities exhibit thin liquid film enhancements, ranging from 3 to 90. Close to the cold limit of water stability (i.e. 273 K), thin liquid film thicknesses at the surface of the Martian regolith is 0.06 nm (pure water ice) and ranges from 0.2 to 5 nm (water ice with impurities). An adsorbed water layer of 0.06 nm implies a dessicated surface as the thickness of one monolayer of water is 0.3 nm but represents 0.001-0.02% of the Martian atmospheric water vapour inventory. Taking into account the specific surface area (SSA) of surface-soil (i.e. top 1 mm of regolith and 0.06 nm adsorbed water layer), shows Martian surface-soil may contain interfacial water that represents 6-66% of the upper- and lower-limit atmospheric water vapour inventory and almost four times and 33%, the lower- and upper-limit Martian atmospheric water vapour inventory. Similarly, taking the SSA of Martian soil, the top 1 mm or regolith at 5 nm thin liquid water thickness, yields 1.10×1013 and 6.50×1013 litres of waters, respectively, 55-325 times larger than Mars' atmospheric water vapour inventory. Film thicknesses of 0.2 and 5 nm represent 2.3×104-1.5×106 litres of water, which is 6.0×10-7-4.0×10-4%, respectively, of a 10 pr μm water vapour column, and 3.0×10-6-4.0×10-4% and 6.0×10

  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. Storm impacts upon the composition of organic matrices in Nagara River--a study based on molecular weight and activated carbon adsorbability.

    PubMed

    Li, Fusheng; Yuasa, Akira; Chiharada, Hajime; Matsui, Yoshihiko

    2003-09-01

    The impacts of a heavy storm of rain on the composition of natural organic matter (NOM) in Nagara River water were studied in terms of molecular weights (MWs) and activated carbon (AC) adsorbabilities using six water samples collected during a critical Typhoon weather condition. The composition in MWs was analyzed using a HPSEC system and that in adsorbabilities was characterized using parameters devised to reflect NOMs average adsorptive strength (K(M)), adsorptive strength polydispersity (sigma), affinity to AC (1/n) and non-adsorbable fraction (C(non)/C(T0)), respectively. These parameters were determined by model description of observed isotherms with a distributed fictive component method. The heavy storm of rain brought higher content of larger organic components into the river source, thus causing changes of NOMs weight-averaged MWs in the range of 2962-3495 Dalton and MW polydispersity in the narrow range of 1.153-1.226. Comparison of K(M) and sigma values for all samples assessed with both indices of TOC and UV260 showed that large proportions of the storm-induced organic components had adsorptive strengths similar to those existent before the storm, with the presence levels for components revealing much strong and weak adsorbabilities being low. Among all organic components brought into the river by the storm of rain, the percentages of non-adsorbable ones was lower (smaller C(non)/C(T0) values); and the adsorbable ones had generally more affinity to the adsorbents used (smaller 1/n values).

  17. 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.

  18. 20 CFR 340.2 - Amount recoverable.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 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 Act...

  19. Extracting Uranium from Seawater: Promising AF Series Adsorbents

    SciTech Connect

    Das, S.; Oyola, Y.; Mayes, Richard T.

    A new family of high-surface-area polyethylene fiber adsorbents named the AF series was recently developed at the Oak Ridge National Laboratory (ORNL). The AF series adsorbents were synthesized by radiation-induced graft polymerization of acrylonitrile and itaconic acid (at different monomer/comonomer 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 0.44 M KOH at 80 °C followed by screening at ORNL with sodium-based synthetic aqueous solution, spiked withmore » 8 ppm uranium. The uranium adsorption capacity in simulated seawater screening ranged from 170 to 200 g-U/kg-ads irrespective of %DOG. A monomer/comonomer molar 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 column experiments to determine uranium loading capacity with varying KOH conditioning times 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 1 and 3 h of KOH conditioning at 80 °C, respectively. Based on capacity values of several AF1 samples, it was observed that changing KOH conditioning from 1 to 3 h at 80 °C resulted in a 22-27% decrease in uranium adsorption capacity in seawater.« less

  20. Activity, conformation and dynamics of cutinase adsorbed on poly(methyl methacrylate) latex particles.

    PubMed

    Baptista, R P; Santos, A M; Fedorov, A; Martinho, J M G; Pichot, C; Elaïssari, A; Cabral, J M S; Taipa, M A

    2003-05-08

    The adsorption of a recombinant cutinase from Fusarium solani pisi onto the surface of 100 nm diameter poly(methyl methacrylate) (PMMA) latex particles was evaluated. Adsorption of cutinase is a fast process since more than 70% of protein molecules are adsorbed onto PMMA at time zero of experiment, irrespective of the tested conditions. A Langmuir-type model fitted both protein and enzyme activity isotherms at 25 degrees C. Gamma(max) increased from 1.1 to 1.7 mg m(-2) and U(max) increased from 365 to 982 U m(-2) as the pH was raised from 4.5 to 9.2, respectively. A decrease (up to 50%) in specific activity retention was observed at acidic pH values (pH 4.5 and 5.2) while almost no inactivation (eta(act) congruent with 87-94%) was detected upon adsorption at pH 7.0 and 9.2. Concomitantly, far-UV circular dichroism (CD) spectra evidenced a reduction in the alpha-helical content of adsorbed protein at acidic pH values while at neutral and alkaline pH the secondary structure of adsorbed cutinase was similar to that of native protein. Fluorescence anisotropy decays showed the release of some constraints to the local motion of the Trp69 upon protein adsorption at pH 8.0, probably due to the disruption of the tryptophan-alanine hydrogen bond when the tryptophan interacts with the PMMA surface. Structural data associated with activity measurements at pH 7.0 and 9.2 showed that cutinase adsorbs onto PMMA particles in an end-on orientation with active site exposed to solvent and full integrity of cutinase secondary structure. Hydrophobic interactions are likely the major contribution to the adsorption mechanism at neutral and alkaline pH values, and a higher amount of protein is adsorbed to PMMA particles with increasing temperature at pH 9.2. The maximum adsorption increased from 88 to 140 mg cutinase per g PMMA with temperature raising from 25 to 50 degrees C, at pH 9.2.

  1. 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. Copyright © 2015 Elsevier B.V. All rights reserved.

  2. 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. © 2016 Wiley Periodicals, Inc.

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

    PubMed

    Abouelnasr, Mahmoud K F; Smit, Berend

    2012-09-07

    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.

  4. 14 CFR 1300.13 - Guarantee amount.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 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 § 1300... loan amount guaranteed to a single air carrier may not exceed that amount that, in the Board's sole...

  5. 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 MARITIME ADMINISTRATION, DEPARTMENT OF TRANSPORTATION EMERGENCY OPERATIONS WAR RISK INSURANCE War Risk Hull and Disbursements Insurance § 308.100 Insured amount. An applicant for war risk hull insurance shall...

  6. 46 CFR 308.100 - Insured amount.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 46 Shipping 8 2014-10-01 2014-10-01 false Insured amount. 308.100 Section 308.100 Shipping MARITIME ADMINISTRATION, DEPARTMENT OF TRANSPORTATION EMERGENCY OPERATIONS WAR RISK INSURANCE War Risk Hull and Disbursements Insurance § 308.100 Insured amount. An applicant for war risk hull insurance shall...

  7. 46 CFR 308.100 - Insured amount.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 46 Shipping 8 2013-10-01 2013-10-01 false Insured amount. 308.100 Section 308.100 Shipping MARITIME ADMINISTRATION, DEPARTMENT OF TRANSPORTATION EMERGENCY OPERATIONS WAR RISK INSURANCE War Risk Hull and Disbursements Insurance § 308.100 Insured amount. An applicant for war risk hull insurance shall...

  8. 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 MARITIME ADMINISTRATION, DEPARTMENT OF TRANSPORTATION EMERGENCY OPERATIONS WAR RISK INSURANCE War Risk Hull and Disbursements Insurance § 308.100 Insured amount. An applicant for war risk hull insurance shall...

  9. 46 CFR 308.100 - Insured amount.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 46 Shipping 8 2012-10-01 2012-10-01 false Insured amount. 308.100 Section 308.100 Shipping MARITIME ADMINISTRATION, DEPARTMENT OF TRANSPORTATION EMERGENCY OPERATIONS WAR RISK INSURANCE War Risk Hull and Disbursements Insurance § 308.100 Insured amount. An applicant for war risk hull insurance shall...

  10. 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 the...

  11. 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 the...

  12. 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 the...

  13. 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 the...

  14. 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 the...

  15. 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…

  16. Formic Acid Dissociative Adsorption on NiO(111): Energetics and Structure of Adsorbed Formate

    DOE PAGES

    Zhao, Wei; Doyle, Andrew D.; Morgan, Sawyer E.; ...

    2017-11-21

    Here, the dissociative adsorption of carboxylic acids on oxide surfaces is important for understanding adsorbed carboxylates, which are important as intermediates in catalytic reactions, for the organo-functionalization of oxide surfaces, and in many other aspects of oxide surface chemistry. We present here the first direct experimental measurement of the heat of dissociative adsorption of any carboxylic acid on any single-crystal oxide surface. The enthalpy of the dissociative adsorption of formic acid, the simplest carboxylic acid, to produce adsorbed formate and hydrogen (as a surface hydroxyl) on a (2 × 2)-NiO(111) surface is measured by single crystal adsorption calorimetry. The differentialmore » heat of adsorption decreases with formic acid coverage from 202 to 99 kJ/mol at saturation (0.25 ML). The structure of the adsorbed products is clarified by density functional theory (DFT) calculations, which provide energies in reasonable agreement with the calorimetry. These calculations show that formic acid readily dissociates on both the oxygen and Ni terminations of the octapolar NiO(111) surfaces, donating its acid H to a surface lattice oxygen, while HCOO adsorbs preferentially with bridging-type geometry near the M-O 3/O-M 3 sites. The calculated energetics at low coverages agrees well with experimental data, while larger differences are observed at high coverage (0.25 ML). The large decrease in experimental heat of adsorption with coverage can be brought into agreement with the DFT energies if we assume that both types of octapolar surface terminations (O- and Ni-) are present on the starting surface.« less

  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. Formic Acid Dissociative Adsorption on NiO(111): Energetics and Structure of Adsorbed Formate

    SciTech Connect

    Zhao, Wei; Doyle, Andrew D.; Morgan, Sawyer E.

    Here, the dissociative adsorption of carboxylic acids on oxide surfaces is important for understanding adsorbed carboxylates, which are important as intermediates in catalytic reactions, for the organo-functionalization of oxide surfaces, and in many other aspects of oxide surface chemistry. We present here the first direct experimental measurement of the heat of dissociative adsorption of any carboxylic acid on any single-crystal oxide surface. The enthalpy of the dissociative adsorption of formic acid, the simplest carboxylic acid, to produce adsorbed formate and hydrogen (as a surface hydroxyl) on a (2 × 2)-NiO(111) surface is measured by single crystal adsorption calorimetry. The differentialmore » heat of adsorption decreases with formic acid coverage from 202 to 99 kJ/mol at saturation (0.25 ML). The structure of the adsorbed products is clarified by density functional theory (DFT) calculations, which provide energies in reasonable agreement with the calorimetry. These calculations show that formic acid readily dissociates on both the oxygen and Ni terminations of the octapolar NiO(111) surfaces, donating its acid H to a surface lattice oxygen, while HCOO adsorbs preferentially with bridging-type geometry near the M-O 3/O-M 3 sites. The calculated energetics at low coverages agrees well with experimental data, while larger differences are observed at high coverage (0.25 ML). The large decrease in experimental heat of adsorption with coverage can be brought into agreement with the DFT energies if we assume that both types of octapolar surface terminations (O- and Ni-) are present on the starting surface.« less

  19. Vibrational Studies of Adsorbate-Induced Reconstruction on Molybdenum Surfaces.

    NASA Astrophysics Data System (ADS)

    Lopinski, Gregory Peter

    Adsorbate-induced rearrangement of the substrate structure strongly modifies the adsorbate-substrate and adsorbate-adsorbate interactions, leading to the complex behavior observed in many chemisorption systems. In this thesis the H/Mo(211), O/Mo(211) and Na/Mo(100) systems have been studied using high resolution electron energy loss spectroscopy (HREELS) to observe vibrations of the adsorbed atoms. The vibrational data is correlated with observations of the long-range order probed by LEED as well as the work function changes induced by adsorption. Adsorbate -induced substrate reconstruction plays an important role in all three of these systems. Studies of the coadsorption systems O+H/Mo(211) and Na+O/Mo(100) indicate how these effects can influence interactions between adsorbates. For H/Mo(211), above 1ML a (1 x 1) to (1 x 2) transition is observed and attributed to modification of the substrate periodicity. Below 1ML, H atoms are bridge bonded and induce local distortions of the substrate. The transition to the (1 x 2) phase involves the ordering of these displacements and occupation of three-fold sites partially populated by conversion of the bridge bonded species. This conversion accounts for the sawtooth-like coverage dependence of the work function. The structural model proposed for this system is also supported by the desorption parameters and partial molar entropy extracted from adsorption isobars. Oxygen adsorption on Mo(211) involves the occupation of multiple binding sites, with both the long-range order and the local geometry of the adsorbate phases strongly temperature dependent. Coadsorption of low coverages of oxygen and hydrogen leads to segregation of the two adsorbates which can be understood in terms of a substrate-mediated repulsive interaction between O and H. For Na/Mo(100), the frequency of the Na-Mo symmetric stretch mode does not shift with coverage although the mode intensity is strongly coverage dependent. The absence of a frequency shift

  20. 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

  1. Framework for scalable adsorbate–adsorbate interaction models

    DOE PAGES

    Hoffmann, Max J.; Medford, Andrew J.; Bligaard, Thomas

    2016-06-02

    Here, we present a framework for physically motivated models of adsorbate–adsorbate interaction between small molecules on transition and coinage metals based on modifications to the substrate electronic structure due to adsorption. We use this framework to develop one model for transition and one for coinage metal surfaces. The models for transition metals are based on the d-band center position, and the models for coinage metals are based on partial charges. The models require no empirical parameters, only two first-principles calculations per adsorbate as input, and therefore scale linearly with the number of reaction intermediates. By theory to theory comparison withmore » explicit density functional theory calculations over a wide range of adsorbates and surfaces, we show that the root-mean-squared error for differential adsorption energies is less than 0.2 eV for up to 1 ML coverage.« less

  2. 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.

  3. 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.

  4. 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.

  5. Extracting uranium from seawater: Promising AF series adsorbents

    DOE PAGES

    Das, Sadananda; Oyola, Y.; Mayes, Richard T.; ...

    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

  6. Extracting uranium from seawater: Promising AF series adsorbents

    SciTech Connect

    Das, Sadananda; Oyola, Y.; Mayes, Richard T.

    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

  7. 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.

  8. Penicillium sp. strain that efficiently adsorbs lignosulfonate in the presence of sulfate ion.

    PubMed

    Aoyama, Akihisa; Kurane, Ryuichiro; Nagai, Kazuo

    2013-03-01

    Lignin is one of the major water insoluble substances that support the physical properties of plants and can be solubilized by sulfite or alkaline treatment in accordance with pulpification. The lignin derivatives produced by both the sulfite and the kraft processes are called lignosulfonate (LS) and kraft lignin (KL), respectively, and both derivatives show a broad spectrum of optical absorbance from ultraviolet to visible light. When the spore suspension of an isolated Penicillium sp., Penicillium sp. A, was inoculated to a medium containing 0.1% commercial LS, absorbance at 480 nm (A480) almost completely disappeared after 5 days of cultivation. Maximum decolorization of the culture broth was observed when the microbe was cultured in the 0.8% LS medium reaching 88%, and the amount of LS removed was calculated to be 7 g/L. In a similar assay with the dark-liquid containing KL, 80% of the A480 of a 20% (v/v) dark-liquid medium disappeared after 5 days of culturing and the amount of KL removed was calculated to be 2.9 g/L. These values significantly exceeded the previously reported amounts with respect to substrate concentration and decolorization. Furthermore, since similar results were obtained in the cases of both LS and KL, it is expected that the present strain is able to non-specifically adsorb a wide range of lignin derivatives, because most of the colored substances were recovered in the culture sediments. Thus, the strain can be used to clean up waste fluids containing water soluble lignin derivatives, adsorb lignin derivatives in waste fluids before dehydration. Copyright © 2012 The Society for Biotechnology, Japan. Published by Elsevier B.V. All rights reserved.

  9. 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.

  10. SERS spectra of pyridine adsorbed on nickel film prepared by magnetron sputtering

    NASA Astrophysics Data System (ADS)

    Li, Daoyong; Ouyang, Yu; Chen, Li; Cao, Weiran; Shi, Shaohua

    2011-02-01

    As a repeating well and cheaper enhancement substrate, the nickel film was fabricated with magnetron sputtering coating instrument. Surface enhanced Raman spectra (SERS) of pyridine adsorbed on this nickel film are compared with the experimental values of gaseous pyridine, the theoretical value of pyridine solution listed in other literatures and our method is better than electro-chemical etching electrode method for large scale preparation. The enhancement factor of the nickel film is calculated and the result indicates that magnetron sputtering coating technology is feasible for obtaining good SERS active surface.

  11. Adsorbed Molecules and Surface Treatment Effect on Optical Properties of ZnO Nanowires Grown by MOCVD

    NASA Astrophysics Data System (ADS)

    Jabri, S.; Souissi, H.; Sallet, V.; Lusson, A.; Meftah, A.; Galtier, P.; Oueslati, M.

    2017-07-01

    We have investigated the optical properties of ZnO nanowires grown by metalorganic chemical vapor deposition (MOCVD) with nitrous oxide (N2O) as oxygen precursor. Photoluminescence (PL) and Raman measurements showed the influence of adsorbed molecules on the optical properties. Low-temperature (4 K) PL studies on the surface exciton (SX) at 3.3660 eV elucidated the nature and origin of this emission. In particular, surface treatment by annealing at high temperature under inert gas reduced the emission intensity of SX. Raman vibrational spectra proved that presence of a considerable amount of adsorbed molecules on the surface of ZnO nanowires plays a key role in the occurrence of surface excitons.

  12. The influence of adsorbent microstructure upon adsorption equilibria: Investigations of a model system

    NASA Astrophysics Data System (ADS)

    Kaminsky, R. D.; Monson, P. A.

    1991-08-01

    We present a theoretical study of the influence of the microstructure of a porous adsorbent upon associated adsorption behavior. A model is developed which describes the interactions of adsorbed molecules with an adsorbent treated as a matrix of particles each of which is a continuum of interaction centers. The model leads to an analytic expression for the adsorbate-adsorbent particle potential which is an analog of the 9-3 potential model for adsorption on planar solid surfaces. To illustrate the utility of the approach, an application to methane adsorbed in a microporous silica gel is presented. Several adsorbent microstructures are investigated, including a variety of crystal lattices as well as structures derived from equilibrium configurations of hard spheres. Adsorption in these structures is studied through calculation of Henry's law constants and by using grand canonical Monte Carlo simulation to determine adsorption isotherms and the structure of adsorbed fluids. The results obtained are related to details of the adsorbent microstructure.

  13. 77 FR 59618 - Medicare Program; Medicare Appeals; Adjustment to the Amount in Controversy Threshold Amounts for...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-09-28

    ...This notice announces the annual adjustment in the amount in controversy (AIC) threshold amounts for Administrative Law Judge (ALJ) hearings and judicial review under the Medicare appeals process. The adjustment to the AIC threshold amounts will be effective for requests for ALJ hearings and judicial review filed on or after January 1, 2013. The calendar year 2013 AIC threshold amounts are $140 for ALJ hearings and $1,400 for judicial review.

  14. 78 FR 59702 - Medicare Program; Medicare Appeals: Adjustment to the Amount in Controversy Threshold Amounts for...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-09-27

    ...This notice announces the annual adjustment in the amount in controversy (AIC) threshold amounts for Administrative Law Judge (ALJ) hearings and judicial review under the Medicare appeals process. The adjustment to the AIC threshold amounts will be effective for requests for ALJ hearings and judicial review filed on or after January 1, 2014. The calendar year 2014 AIC threshold amounts are $140 for ALJ hearings and $1,430 for judicial review.

  15. 76 FR 59138 - Medicare Program; Medicare Appeals; Adjustment to the Amount in Controversy Threshold Amounts for...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-09-23

    ...This notice announces the annual adjustment in the amount in controversy (AIC) threshold amounts for Administrative Law Judge (ALJ) hearings and judicial review under the Medicare appeals process. The adjustment to the AIC threshold amounts will be effective for requests for ALJ hearings and judicial review filed on or after January 1, 2012. The calendar year 2012 AIC threshold amounts are $130 for ALJ hearings and $1,350 for judicial review.

  16. 75 FR 58407 - Medicare Program; Medicare Appeals; Adjustment to the Amount in Controversy Threshold Amounts for...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-09-24

    ...This notice announces the annual adjustment in the amount in controversy (AIC) threshold amounts for Administrative Law Judge (ALJ) hearings and judicial review under the Medicare appeals process. The adjustment to the AIC threshold amounts will be effective for requests for ALJ hearings and judicial review filed on or after January 1, 2011. The 2011 AIC threshold amounts are $130 for ALJ hearings and $1,300 for judicial review.

  17. 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.

  18. 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%.

  19. Removal of dieldrin from aqueous solution by a novel triolein-embedded composite adsorbent.

    PubMed

    Ru, Jia; Liu, Huijuan; Qu, Jiuhui; Wang, Aimin; Dai, Ruihua

    2007-03-06

    In this study, a novel triolein-embedded activated carbon composite adsorbent (CA-T) was prepared and applied for the adsorption and removal of dieldrin from aqueous systems. Experiments were carried out to investigate the adsorption behavior of dieldrin on CA-T, including adsorption isotherms, adsorption kinetics, the influence of initial concentration, temperature, shaking speed, pH and the addition of humic acid (HA) on adsorption. The adsorption isotherms accorded with Freundlich equation. Three kinetics models, including pseudo-first-order, pseudo-second-order and intraparticle diffusion models, were used to fit the experimental data. By comparing the correlation coefficients, it was found that both pseudo-second-order and intraparticle diffusion models were used to well describe the adsorption of dieldrin on CA-T. The addition of HA had little effect on dieldrin adsorption by CA-T. Results indicated that CA-T appeared to be a promising adsorbent for removing lipophilic dieldrin in trace amount, which was advantageous over pure granular activated carbon (GAC). The adsorption rate increased with increasing shaking speed, initial concentration and temperature, and remained almost unchanged in the pH range of 4-8. Thermodynamic calculations indicated that the adsorption reaction was spontaneous with a high affinity and the adsorption was an endothermic reaction.

  20. A novel approach for arsenic adsorbents regeneration using MgO.

    PubMed

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

    2014-01-30

    An integrated procedure for the regeneration of iron oxy-hydroxide arsenic adsorbents by granulated MgO is proposed in this study. A continuous recirculation configuration, with a NaOH solution flowing sequentially through the saturated adsorbent (leaching step) and the MgO (adsorption step) column beds, was optimized by utilizing the high arsenic adsorption efficiency of MgO at strong alkaline environments. Experimental results indicated that the total amount of leached arsenic was captured by MgO whereas the regenerated iron oxy-hydroxide recovered around 80% of its removal capacity upon reuse. The improved adsorption capacity of MgO for As(V), which is maximized at pH 10, is explained by the intermediate hydration to Mg(OH)2 and the following As(V) oxy-anions adsorption on its surface through the formation of monodentate inner sphere complexes, as it is deduced from the AsK-edge X-ray absorption fine structure (EXAFS) analysis. In addition to the economical-benefits, corresponding tests proved that the solid wastes of this process, namely spent MgO/Mg(OH)2, can be environmentally safely disposed as stable additives in cement products, while the alkaline solution is completely detoxified and can be recycled to the regeneration task. Copyright © 2013 Elsevier B.V. All rights reserved.

  1. Kinetic Assembly of Near-IR Active Gold Nanoclusters using Weakly Adsorbing Polymers to Control Size

    PubMed Central

    Tam, Jasmine M.; Murthy, Avinash K.; Ingram, Davis R.; Nguyen, Robin; Sokolov, Konstantin V.; Johnston, Keith P.

    2013-01-01

    Clusters of metal nanoparticles with an overall size less than 100 nm and high metal loadings for strong optical functionality, are of interest in various fields including microelectronics, sensors, optoelectronics and biomedical imaging and therapeutics. Herein we assemble ~5 nm gold particles into clusters with controlled size, as small as 30 nm and up to 100 nm, which contain only small amounts of polymeric stabilizers. The assembly is kinetically controlled with weakly adsorbing polymers, PLA(2K)-b-PEG(10K)-b-PLA(2K) or PEG (MW = 3350), by manipulating electrostatic, van der Waals (VDW), steric, and depletion forces. The cluster size and optical properties are tuned as a function of particle volume fractions and polymer/gold ratios to modulate the interparticle interactions. The close spacing between the constituent gold nanoparticles and high gold loadings (80–85% w/w gold) produce a strong absorbance cross section of ~9×10−15 m2 in the NIR at 700 nm. This morphology results from VDW and depletion attractive interactions that exclude the weakly adsorbed polymeric stabilizer from the cluster interior. The generality of this kinetic assembly platform is demonstrated for gold nanoparticles with a range of surface charges from highly negative to neutral, with the two different polymers. PMID:20361735

  2. The Density and Refractive Index of Adsorbing Protein Layers

    PubMed Central

    Vörös, Janos

    2004-01-01

    The structure of the adsorbing layers of native and denatured proteins (fibrinogen, γ-immunoglobulin, albumin, and lysozyme) was studied on hydrophilic TiO2 and hydrophobic Teflon-AF surfaces using the quartz crystal microbalance with dissipation and optical waveguide lightmode spectroscopy techniques. The density and the refractive index of the adsorbing protein layers could be determined from the complementary information provided by the two in situ instruments. The observed density and refractive index changes during the protein-adsorption process indicated the presence of conformational changes (e.g., partial unfolding) in general, especially upon contact with the hydrophobic surface. The structure of the formed layers was found to depend on the size of the proteins and on the experimental conditions. On the TiO2 surface smaller proteins formed a denser layer than larger ones and the layer of unfolded proteins was less dense than that adsorbed from the native conformation. The hydrophobic surface induced denaturation and resulted in the formation of thin compact protein films of albumin and lysozyme. A linear correlation was found between the quartz crystal microbalance measured dissipation factor and the total water content of the layer, suggesting the existence of a dissipative process that is related to the solvent molecules present inside the adsorbed protein layer. Our measurements indicated that water and solvent molecules not only influence the 3D structure of proteins in solution but also play a crucial role in their adsorption onto surfaces. PMID:15240488

  3. 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...

  4. Characteristics of Microactive Carbon from Bamboo Var. Petung as Adsorbent

    NASA Astrophysics Data System (ADS)

    Wirawan, I. P. S.; Sutrisno; Seminar, K. B.; Nelwan, L. O.

    2018-05-01

    Bamboo has unique characteristics, such as in the carbonization process at a temperature of 500°C, the carbon characteristics is homogeneous. The characteristics of bamboo have great potential as a future bio-energy resource. Apart from being a bio-energy source of bamboo can also be used as an adsorbent material in the form of activated carbon. Activated carbon is the most inexpensive and easy to produce adsorbent material. One of the activated carbons of bamboo materials used is the micro-active carbon from bamboo. Microactivated carbon bamboo has a pore structure which is good for adsorption because of its surface area being much better than the other adsorbent, mainly on mesopore and micropore pore size. The purpose of this research is to make micro-activated carbon adsorbent bamboo var. petungand to analyze their characteristics. The characteristic of microactivecarbon was analyzed by SEM EDS and Iod number. The result showed a variation in pore size from 1μm to 11.157μm. The surface area of micro-active carbon of 200 mesh and 80 mesh is 1954.95 m2g-1 and 1516.34 m2g-1.

  5. [Management of severe sepsis using a Cytokin-adsorber].

    PubMed

    Houschyar, Khosrow Siamak; Rein, Susanne; Weissenberg, Kristian; Duscher, Dominik; Philipps, Hubertus Maria; Nietzschmann, Ina; Schulz, Torsten; Siemers, Frank

    2018-02-01

    Based on a representative case, which was treated in our center for severe burn injuries, the severity of the Waterhouse-Friderichsen syndrome and the complexity of the prolonged course of treatment are illustrated. Special attention is focused on the new treatment paradigm using the CytoSorb® adsorber.

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

    USDA-ARS?s Scientific Manuscript database

    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...

  7. 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.

  8. Extracting uranium from seawater: Promising AI series adsorbents

    DOE PAGES

    Das, Sadananda; Oyola, Y.; Mayes, Richard T.; ...

    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

  9. Nonadiabatic dynamics of electron scattering from adsorbates in surface bands

    NASA Astrophysics Data System (ADS)

    Gumhalter, Branko; Šiber, Antonio; Buljan, Hrvoje; Fauster, Thomas

    2008-10-01

    We present a comparative study of nonadiabatic dynamics of electron scattering in quasi-two-dimensional surface band which is induced by the long-range component of the interactions with a random array of adsorbates. Using three complementary model descriptions of intraband spatiotemporal propagation of quasiparticles that go beyond the single-adsorbate scattering approach we are able to identify distinct subsequent regimes of evolution of an electron following its promotion into an unoccupied band state: (i) early quadratic or ballistic decay of the initial-state survival probability within the Heisenberg uncertainty window, (ii) preasymptotic exponential decay governed by the self-consistent Fermi golden rule scattering rate, and (iii) asymptotic decay described by a combined inverse power-law and logarithmic behavior. The developed models are applied to discuss the dynamics of intraband adsorbate-induced scattering of hot electrons excited into the n=1 image-potential band on Cu(100) surface during the first stage of a two-photon photoemission process. Estimates of crossovers between the distinct evolution regimes enable assessments of the lifespan of a standard quasiparticle behavior and thereby of the range of applicability of the widely used Fermi golden rule and optical Bloch equations approach for description of adsorbate-induced quasiparticle decay and dephasing in ultrafast experiments.

  10. 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)

  11. Gd uptake experiments for preliminary set of functionalized adsorbents

    DOE Data Explorer

    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.

  12. Unusual Entropy of Adsorbed Methane on Zeolite-Templated Carbon

    SciTech Connect

    Stadie, Nicholas P.; Murialdo, Maxwell; Ahn, Channing C.

    2015-11-25

    Methane adsorption at high pressures and across a wide range of temperatures was investigated on the surface of three porous carbon adsorbents with complementary structural properties. The measured adsorption equilibria were analyzed using a method that can accurately account for nonideal fluid properties and distinguish between absolute and excess quantities of adsorption, and that also allows the direct calculation of the thermodynamic potentials relevant to adsorption. On zeolite-templated carbon (ZTC), a material that exhibits extremely high surface area with optimal pore size and homogeneous structure, methane adsorption occurs with unusual thermodynamic properties that are greatly beneficial for deliverable gas storage:more » an enthalpy of adsorption that increases with site occupancy, and an unusually low entropy of the adsorbed phase. The origin of these properties is elucidated by comparison of the experimental results with a statistical mechanical model. The results indicate that temperature-dependent clustering (i.e., reduced configurations) of the adsorbed phase due to enhanced lateral interactions can account for the peculiarities of methane adsorbed on ZTC.« less

  13. 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...

  14. Extracting uranium from seawater: Promising AI series adsorbents

    SciTech Connect

    Das, Sadananda; Oyola, Y.; Mayes, Richard T.

    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

  15. Extracting Uranium from Seawater: Promising AI Series Adsorbents

    SciTech Connect

    Das, S.; Oyola, Y.; Mayes, R. T.

    A new series of adsorbents (AI10 through AI17) were successfully developed at ORNL by radiation induced graft polymerization (RIGP) of acrylonitrile (AN) and vinylphosphonic acid (VPA) (at different mole to mole ratios) onto high surface area polyethylene fiber, with high degrees of grafting (DOG) varying from 110 to 300%. The grafted nitrile groups were converted to amidoxime groups by reaction with 5 wt % hydroxylamine at 80 °C for 72 h. The amidoximated adsorbents were then conditioned with 0.44 M KOH at 80 °C followed by screening at ORNL with prescreening brine spiked with 8 ppm uranium. Uranium adsorption capacitiesmore » in prescreening ranged from 171 to 187 g-U/kg-ads irrespective of percent DOG. The performance of the adsorbents with respect to uranium adsorption in natural seawater was also investigated using flow-throughcolumn testing at the Pacific Northwest National Laboratory (PNNL). Three hours of KOH conditioning led to higher uranium uptake than 1 h of conditioning. The adsorbent AI11, containing AN and VPA at the mole ratio of 3.52, emerged as the potential candidate for the highest uranium adsorption (3.35 g-U/kg-ads.) after 56 days of exposure in seawater flow-through-columns. The rate of vanadium adsorption over uranium linearly increased throughout the 56 days of exposure. The total mass of vanadium uptake was ~5 times greater than uranium after 56 days.« less

  16. 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.

  17. Enhanced encapsulation of metoprolol tartrate with carbon nanotubes as adsorbent

    NASA Astrophysics Data System (ADS)

    Garala, Kevin; Patel, Jaydeep; Patel, Anjali; Dharamsi, Abhay

    2011-12-01

    A highly water-soluble antihypertensive drug, metoprolol tartrate (MT), was selected as a model drug for preparation of multi-walled carbon nanotubes (MWCNTs)-impregnated ethyl cellulose (EC) microspheres. The present investigation was aimed to increase encapsulation efficiency of MT with excellent adsorbent properties of MWCNTs. The unique surface area, stiffness, strength and resilience of MWCNTs have drawn much anticipation as carrier for highly water-soluble drugs. Carbon nanotubes drug adsorbate (MWCNTs:MT)-loaded EC microspheres were further optimized by the central composite design of the experiment. The effects of independent variables (MWCNTs:MT and EC:adsorbate) were evaluated on responses like entrapment efficiency (EE) and t 50 (time required for 50% drug release). The optimized batch was compared with drug alone EC microspheres. The results revealed high degree of improvement in encapsulation efficiency for MWCNTs:MT-loaded EC microspheres. In vitro drug release study exhibited complete release form drug alone microspheres within 15 h, while by the same time only 50-60% drug was released for MWCNTs-impregnated EC microspheres. The optimized batch was further characterized by various instrumental analyses such as scanning electron microscopy, powder X-ray diffraction and differential scanning calorimetry. The results endorse encapsulation of MWCNTs:MT adsorbate inside the matrix of EC microspheres, which might have resulted in enhanced encapsulation and sustained effect of MT. Hence, MWCNTs can be utilized as novel carriers for extended drug release and enhanced encapsulation of highly water-soluble drug, MT.

  18. Determination of Adsorption Capacity and Kinetics of Amidoxime-Based Uranium Adsorbent Braided Material in Unfiltered Seawater Using a Flume Exposure System

    SciTech Connect

    Gill, Gary A.; Kuo, Li-Jung; Strivens, Jonathan E.

    days. The amount of biomass increase retained by the adsorbent in the dark flume was only a quarter of that observed in the light-exposed flume. Biofouling in sunlit surface seawater has the potential to reduce uranium adsorption capacity by ~30% after 42 days of exposure. Minimal or no adsorption loss due to biofouling occurred in the dark flume exposure. Attempts to assess time series measurements of uranium adsorption capacity using “snips” off a master braid are fraught with problems due to the inability to easily determine the mass of the adsorbent material when the biofouling is present. The ability to determine the adsorption of biogenically important trace elements (e.g. Fe, Mn, Zn, Cu, and Sr) on biofouled adsorbents is also problematic.« less

  19. Magnetic copper-based metal organic framework as an effective and recyclable adsorbent for removal of two fluoroquinolone antibiotics from aqueous solutions.

    PubMed

    Wu, Gege; Ma, Jiping; Li, Shuang; Guan, Jing; Jiang, Bo; Wang, Liyan; Li, Jinhua; Wang, Xiaoyan; Chen, Lingxin

    2018-05-30

    Fe 3 O 4 /HKUST-1 magnetic copper based metal-organic frameworks (MOF) were synthesized by a simple and facile method and applied as an effective and recyclable adsorbent for the adsorptive removal of two widely used ciprofloxacin (CIP) and norfloxacin (NOR) fluoroquinolone antibiotics (FQAs) from aqueous solutions. Fe 3 O 4 /HKUST-1 was thoroughly characterized, and the major influence factors including solution pH, adsorbent amount and salt concentration were investigated. Compared to the reported adsorbents, Fe 3 O 4 /HKUST-1 has a very high adsorption rate, and it is found that CIP and NOR could be removed within 30 min. Moreover, the maximum adsorption capacities of the magnetic composites toward CIP and NOR reached as high as 538 mg g -1 and 513 mg g -1 , respectively, much higher than those of most of the reported adsorbents for these two FQAs. The saturation magnetization value of Fe 3 O 4 /HKUST-1 was 44 emu g -1 , which was sufficient for the separation of the Fe 3 O 4 /HKUST-1adsorbent from the aqueous solution by the application of an external magnetic field. Additionally, this magnetic material showed a good reusability with the adsorption capability decreasing only slightly after reuse for ten cycles. These results indicated that the magnetic composites Fe 3 O 4 /HKUST-1 may be a promising adsorbent in the decontamination of FQAs from wastewater due to its high adsorption capability, fast kinetics, easy separation from water, and excellent recyclability. The adsorption mechanism was proposed based on the effects of pH on adsorption and on the zeta potential of the adsorbent. For the adsorption of CIP and NOR by Fe 3 O 4 /HKUST-1, both electrostatic and π-π interactions may be important. Copyright © 2018 Elsevier Inc. All rights reserved.

  20. Effect of the morphology of adsorbed oleate on the wettability of a collophane surface

    NASA Astrophysics Data System (ADS)

    Ye, Junjian; Zhang, Qin; Li, Xianbo; Wang, Xianchen; Ke, Baolin; Li, Xianhai; Shen, Zhihui

    2018-06-01

    The adsorption of surfactants on a solid surface could alter its wettability, which offers a wide range of relevant applications such as mineral flotation, hydrophobic material preparation and nanomaterial dispersion. The morphology of adsorbed oleate on a collophane surface was visualized using the peakforce tapping mode of atomic force microscopy (AFM), and its effect on the wettability of collophane was analysed by contact angle measurements, adsorption measurements and molecular dynamics (MD) simulations. The AFM images demonstrated that the adsorbed structure varied with different oleate concentrations. First, the small cylindrical micelles with concomitant monolayer and bilayer structures were observed above the hemimicelle concentration (hmc) of 1 × 10-5 mol/L, which enhanced the hydrophobicity of the collophane surface, and the collophane surface was not completely covered with the oleate monolayer due to surface heterogeneity. Then, large cylindrical micelles with a major bilayer were formed as the critical micelle concentration (cmc) of 1 × 10-3 mol/L was approached, which decreased its hydrophobicity, and finally the formation of large cylindrical micelles with multilayer at the cmc caused the hydrophilicity of the collophane surface. Therefore, there was a suitable equilibrium concentration between the hmc and cmc for oleate as a collector during mineral flotation, and oleate could also be used as a dispersant for colloidal stability when its equilibrium concentration reached the cmc. The effect of the adsorbed structure on the wettability of collophane was also confirmed by MD simulations. This study provides a good understanding of the surface modification of particles by surfactants for flotation and dispersion applications.

  1. Development of silver nanoparticle-doped adsorbents for the separation and recovery of radioactive iodine from alkaline solutions.

    PubMed

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

    2017-11-01

    Removing radioactive iodine from solutions containing fission products is essential for nuclear facility decontamination, radioactive waste treatment, and medical isotope production. For example, the production of high-purity fission 99 Mo by irradiation of 235 U with neutrons involves the removal of iodine from an alkaline solution of the irradiated target (which contains numerous fission products and a large quantity of aluminate ions) using silver-based materials or anion-exchange resins. To be practically applicable, the utilized iodine adsorbent should exhibit a decontamination factor of at least 200. Herein, the separation of radioactive iodine from alkaline solutions was achieved using alumina doped with silver nanoparticles (Ag NPs). Ag NPs have a larger surface area than Ag powder/wires and can thus adsorb iodine more effectively and economically, whereas alumina is a suitable inert support that does not adsorb 99 Mo and is stable under basic conditions. The developed adsorbents with less impurities achieved iodine removal and recovery efficiencies of 99.7 and 62%, respectively, thus being useful for the production of 131 I, a useful medical isotope. Copyright © 2017. Published by Elsevier Ltd.

  2. Patchy reaction-diffusion and population abundance: the relative importance of habitat amount and arrangement

    Treesearch

    Curtis H. Flather; Michael Bevers

    2002-01-01

    A discrete reaction-diffusion model was used to estimate long-term equilibrium populations of a hypothetical species inhabiting patchy landscapes to examine the relative importance of habitat amount and arrangement in explaining population size. When examined over a broad range of habitat amounts and arrangements, population size was largely determined by a pure amount...

  3. 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.

  4. 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. Copyright © 2016 Elsevier Ltd. All rights reserved.

  5. Live microbial cells adsorb Mg2+ more effectively than lifeless organic matter

    NASA Astrophysics Data System (ADS)

    Qiu, Xuan; Yao, Yanchen; Wang, Hongmei; Duan, Yong

    2018-03-01

    The Mg2+ content is essential in determining different Mg-CaCO3 minerals. It has been demonstrated that both microbes and the organic matter secreted by microbes are capable of allocating Mg2+ and Ca2+ during the formation of Mg-CaCO3, yet detailed scenarios remain unclear. To investigate the mechanism that microbes and microbial organic matter potentially use to mediate the allocation of Mg2+ and Ca2+ in inoculating systems, microbial mats and four marine bacterial strains ( Synechococcus elongatus, Staphylococcus sp., Bacillus sp., and Desulfovibrio vulgaris) were incubated in artificial seawater media with Mg/Ca ratios ranging from 0.5 to 10.0. At the end of the incubation, the morphology of the microbial mats and the elements adsorbed on them were analyzed using scanning electronic microscopy (SEM) and energy diffraction spectra (EDS), respectively. The content of Mg2+ and Ca2+ adsorbed by the extracellular polysaccharide substances (EPS) and cells of the bacterial strains were analyzed with atomic adsorption spectroscopy (AAS). The functional groups on the surface of the cells and EPS of S. elongatus were estimated using automatic potentiometric titration combined with a chemical equilibrium model. The results show that live microbial mats generally adsorb larger amounts of Mg2+ than Ca2+, while this rarely is the case for autoclaved microbial mats. A similar phenomenon was also observed for the bacterial strains. The living cells adsorb more Mg2+ than Ca2+, yet a reversed trend was observed for EPS. The functional group analysis indicates that the cell surface of S. elongatus contains more basic functional groups (87.24%), while the EPS has more acidic and neutral functional groups (83.08%). These features may be responsible for the different adsorption behavior of Mg2+ and Ca2+ by microbial cells and EPS. Our work confirms the differential Mg2+ and Ca2+ mediation by microbial cells and EPS, which may provide insight into the processes that microbes use to

  6. Stabilization of arsenic and fluoride bearing spent adsorbent in clay bricks: Preparation, characterization and leaching studies.

    PubMed

    Rathore, Vineet Kumar; Mondal, Prasenjit

    2017-09-15

    The presence of arsenic and fluoride in groundwater has been observed throughout the world. Many technologies have been developed by various research groups in order to tackle this problem. Adsorption has emerged as one of the best possible technique for the removal of arsenic, fluoride and many other pollutants from drinking water. Although a considerable amount of work has been published on the adsorptive removal of arsenic and fluoride, the area related to the management of spent adsorbent is not well explored. Present paper deals with the adsorptive removal of arsenic and fluoride from aqueous solution by three different types of adsorbents, namely, thermally treated laterite (TTL), acid-base treated laterite (ABTL) and aluminum oxide/hydroxide nanoparticles (AHNP). Under the experimental conditions in batch operation, the adsorption capacities of TTL, ABLT and AHNP for arsenic are found to be 6.43 μg/g, 9.25 μg/g and 48.5 μg/g respectively, whereas for fluoride, these values are found as 0.21 mg/g, 0.85 mg/g and 4.65 mg/g respectively. After adsorption, the spent adsorbents have been stabilized in the form of clay bricks. The effects of spent adsorbent concentration on the properties of bricks and their leaching properties are investigated. The bricks have been tested for various properties like density, percentage water absorption, shrinkage, compressive strength and efflorescence. The maximum values of density and shrinkage of the bricks formed are found as 2.3 g/cm 3 and 10.2%, whereas the percentage water absorption and compressive strength of the bricks are found between 11 and 14% and 35 to 150 kgf/cm 2 respectively. All the test results are in accordance with the criteria set by Indian Standards. The leaching test of arsenic and fluoride from the bricks reveals that their maximum values in leachate are 510 μg/L and 2.1 mg/L respectively, which are below the permissible limits of USEPA standards. Copyright © 2017 Elsevier Ltd. All rights

  7. Heterogeneous Reactions of Limonene on Mineral Dust: Impacts of Adsorbed Water and Nitric Acid.

    PubMed

    Lederer, Madeline R; Staniec, Allison R; Coates Fuentes, Zoe L; Van Ry, Daryl A; Hinrichs, Ryan Z

    2016-12-08

    Biogenic volatile organic compounds (BVOCs), including the monoterpene limonene, are a major source of secondary organic aerosol (SOA). While gas-phase oxidation initiates the dominant pathway for BVOC conversion to SOA, recent studies have demonstrated that biogenic hydrocarbons can also directly react with acidic droplets. To investigate whether mineral dust may facilitate similar reactive uptake of biogenic hydrocarbons, we studied the heterogeneous reaction of limonene with mineral substrates using condensed-phase infrared spectroscopy and identified the formation of irreversibly adsorbed organic products. For kaolinite, Arizona Test Dust, and silica at 30% relative humidity, GC-MS identified limonene-1,2-diol as the dominant product with total organic surface concentrations on the order of (3-5) × 10 18 molecules m -2 . Experiments with 18 O-labeled water support a mechanism initiated by oxidation of limonene by surface redox sites forming limonene oxide followed by water addition to the epoxide to form limonenediol. Limonene uptake on α-alumina, γ-alumina, and montmorillonite formed additional products in high yield, including carveol, carvone, limonene oxide, and α-terpineol. To model tropospheric processing of mineral aerosol, we also exposed each mineral substrate to gaseous nitric acid prior to limonene uptake and identified similar surface adsorbed products that were formed at rates 2 to 5 times faster than without nitrate coatings. The initial rate of reaction was linearly dependent on gaseous limonene concentration between 5 × 10 12 and 5 × 10 14 molecules cm -3 (0.22-20.5 ppm) consistent with an Eley-Rideal-type mechanism in which gaseous limonene reacts directly with reactive surface sites. Increasing relative humidity decreased the amount of surface adsorbed products indicating competitive adsorption of surface adsorbed water. Using a laminar flow tube reactor we measured the uptake coefficient for limonene on kaolinite at 25% RH to range from

  8. How restrained eaters perceive the amount they eat.

    PubMed

    Jansen, A

    1996-09-01

    The cognitive model of binge eating states that it is the awareness of a broken diet that disinhibits the restrained eater. It is, according to that model, the perception of having overeaten that triggers disinhibited eating. However, although the perception of the amount eaten plays a central role in cognitive restraint theory, it has never directly been tested how restrained subjects perceive the amount of food they eat. In the present studies, participants were given ad libitum access to large amounts of palatable food and both their perception of the amount eaten and their estimated caloric intake were compared with the amount they actually ate. The restrained participants in these studies ate more than the unrestrained participants. In the first and second studies, the restrained participants consumed 571 and 372 'forbidden' calories respectively, without having the feeling that they had eaten very much, let alone too much. Moreover in both studies, the restrained eaters underestimated their caloric intake, whereas unrestrained eaters estimated their caloric intake quite well. The potential implications of the present findings for the cognitive restraint model are discussed.

  9. Hydrolysis of particulate settleable solids (PSS) in activated sludge is determined by the bacteria initially adsorbed in the sewage.

    PubMed

    Benneouala, Mourad; Bareha, Younès; Mengelle, Evrard; Bounouba, Mansour; Sperandio, Mathieu; Bessiere, Yolaine; Paul, Etienne

    2017-11-15

    Up to half of the organic fraction of an urban wastewater is made up of particulate settleable solids (PSS). In activated sludge process (AS) this material is rapidly adsorbed on to microbial flocs but is only slowly and partially degraded. To better understand and predict the degradation kinetics observed, a determination of the proportion of hydrolytic bacteria is required. As inoculum is usually added in the biodegradation tests, a comparison is required between the roles of bacteria introduced with the inoculum and those attached to the substrate. In this work, respirometric batch experiments were performed on PSS collected from upstream or downstream of the sewers of Toulouse city. Toilet paper (TP) and cellulose, two model particulate substrates, were also investigated. To understand the role of the active biomass in hydrolysis, increasing concentrations of AS were added to a certain amount of PSS or TP. No correlation was observed between the concentration of AS and the rate and duration of degradation of the particulate matter. Simulations performed after calibration of the model ASM-1 allowed the fraction of hydrolytic bacteria to be estimated in both the substrate and the AS-inoculum. Only a very small fraction of the bacteria of AS and of the substrate samples were found to be efficient for hydrolysis. Hydrolysis was mainly initiated by a small proportion of the microorganisms, and especially by cells already attached to PSSs. Moreover, the fraction of bacteria able to hydrolyse large particles present in an inoculum of AS depended on the initial contamination of the surface of the particles. Copyright © 2017 Elsevier Ltd. All rights reserved.

  10. 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 Assistance...

  11. 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 Assistance...

  12. 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 Assistance...

  13. 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 Assistance...

  14. 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 Assistance...

  15. 21 CFR 1309.11 - Fee amounts.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 9 2014-04-01 2014-04-01 false Fee amounts. 1309.11 Section 1309.11 Food and Drugs DRUG ENFORCEMENT ADMINISTRATION, DEPARTMENT OF JUSTICE REGISTRATION OF MANUFACTURERS, DISTRIBUTORS.... (a) For each application for registration or reregistration to manufacture the applicant shall pay an...

  16. 21 CFR 1309.11 - Fee amounts.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 9 2013-04-01 2013-04-01 false Fee amounts. 1309.11 Section 1309.11 Food and Drugs DRUG ENFORCEMENT ADMINISTRATION, DEPARTMENT OF JUSTICE REGISTRATION OF MANUFACTURERS, DISTRIBUTORS.... (a) For each application for registration or reregistration to manufacture the applicant shall pay an...

  17. 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.... (a) For each application for registration or reregistration to manufacture the applicant shall pay an...

  18. 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.... (a) For each application for registration or reregistration to manufacture the applicant shall pay an...

  19. 20 CFR 617.45 - Amount.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 20 Employees' Benefits 3 2010-04-01 2010-04-01 false Amount. 617.45 Section 617.45 Employees' Benefits EMPLOYMENT AND TRAINING ADMINISTRATION, DEPARTMENT OF LABOR TRADE ADJUSTMENT ASSISTANCE FOR... weight authorized under the Federal travel regulations (see 41 CFR part 101-7), between such locations...

  20. 33 CFR 133.7 - Requests: Amount.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 133.7 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) MARINE 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...

  1. 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) MARINE POLLUTION FINANCIAL RESPONSIBILITY AND COMPENSATION OFFSHORE OIL POLLUTION COMPENSATION FUND...

  2. 33 CFR 133.7 - Requests: Amount.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 133.7 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) MARINE 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...

  3. 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 135.203 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) MARINE POLLUTION FINANCIAL RESPONSIBILITY AND COMPENSATION OFFSHORE OIL POLLUTION COMPENSATION FUND...

  4. 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 135.203 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) MARINE POLLUTION FINANCIAL RESPONSIBILITY AND COMPENSATION OFFSHORE OIL POLLUTION COMPENSATION FUND...

  5. 33 CFR 133.7 - Requests: Amount.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 133.7 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) MARINE 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...

  6. 33 CFR 133.7 - Requests: Amount.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 133.7 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) MARINE 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...

  7. 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) MARINE POLLUTION FINANCIAL RESPONSIBILITY AND COMPENSATION OFFSHORE OIL POLLUTION COMPENSATION FUND...

  8. 33 CFR 133.7 - Requests: Amount.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 133.7 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) MARINE 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...

  9. 33 CFR 135.203 - Amount required.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 33 Navigation and Navigable Waters 2 2013-07-01 2013-07-01 false Amount required. 135.203 Section 135.203 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) MARINE POLLUTION FINANCIAL RESPONSIBILITY AND COMPENSATION OFFSHORE OIL POLLUTION COMPENSATION FUND...

  10. 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 Money and Finance: Treasury Office of the Secretary of the Treasury TERRORISM RISK INSURANCE PROGRAM Cap... insurers based on an adjusted PLRP, and aggregate insured losses still remain within the cap on annual...

  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 (3...

  12. 46 CFR 308.403 - Insured amounts.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... MARITIME ADMINISTRATION, DEPARTMENT OF TRANSPORTATION EMERGENCY OPERATIONS WAR RISK INSURANCE War Risk... total amount of war risk insurance obtainable from companies authorized to do an insurance business in a... not included in the contract price: Provided, that no war risk insurance is obtainable from companies...

  13. 46 CFR 308.403 - Insured amounts.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... MARITIME ADMINISTRATION, DEPARTMENT OF TRANSPORTATION EMERGENCY OPERATIONS WAR RISK INSURANCE War Risk... total amount of war risk insurance obtainable from companies authorized to do an insurance business in a... not included in the contract price: Provided, That no war risk insurance is obtainable from companies...

  14. 46 CFR 308.403 - Insured amounts.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... MARITIME ADMINISTRATION, DEPARTMENT OF TRANSPORTATION EMERGENCY OPERATIONS WAR RISK INSURANCE War Risk... total amount of war risk insurance obtainable from companies authorized to do an insurance business in a... not included in the contract price: Provided, That no war risk insurance is obtainable from companies...

  15. 46 CFR 308.403 - Insured amounts.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... MARITIME ADMINISTRATION, DEPARTMENT OF TRANSPORTATION EMERGENCY OPERATIONS WAR RISK INSURANCE War Risk... total amount of war risk insurance obtainable from companies authorized to do an insurance business in a... not included in the contract price: Provided, That no war risk insurance is obtainable from companies...

  16. 46 CFR 308.403 - Insured amounts.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... MARITIME ADMINISTRATION, DEPARTMENT OF TRANSPORTATION EMERGENCY OPERATIONS WAR RISK INSURANCE War Risk... total amount of war risk insurance obtainable from companies authorized to do an insurance business in a... not included in the contract price: Provided, That no war risk insurance is obtainable from companies...

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

    SciTech Connect

    Li, Tsung-Lung, E-mail: quantum@mail.ncyu.edu.tw; Lu, Wen-Cai, E-mail: wencailu@jlu.edu.cn; State Key Laboratory of Theoretical and Computational Chemistry, Institute of Theoretical Chemistry, Jilin University, Changchun, Jilin 130021

    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,more » 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

  18. Modifying protein adsorption by layers of glutathione pre-adsorbed on Au(111)

    NASA Astrophysics Data System (ADS)

    Vallée, Anne; Humblot, Vincent; Méthivier, Christophe; Dumas, Paul; Pradier, Claire-Marie

    2011-12-01

    Molecular interaction with metal surfaces raises fundamental questions regarding their binding tendency, their dispersion on the surface, as well as their conformation which may change their biological properties; addressing these questions, and being able to tune protein interactions, is of primary importance for the control of biointerfaces. In this study, one tripeptide, GSH (glu-cys-gly), was used to condition gold surfaces and thus influence the adsorption of bovine serum albumin (BSA). Depending on the pH value of the GSH solution, cationic, zwitterionic or anionic forms of the tripeptide could be stabilised on the surface, before interacting with BSA solutions. The amount of proteins was observed to depend both on the chemical state of the adsorbed underlying peptide and on the solvent of the protein solution, indicating an important role of electrostatic interactions upon protein adsorption. Moreover, atomic force microscopy (AFM), and synchrotron IR microscopy revealed a heterogeneous distribution of proteins on the GSH layer.

  19. 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

  20. 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.

  1. Sum frequency generation and solid-state NMR study of the structure, orientation, and dynamics of polystyrene-adsorbed peptides

    PubMed Central

    Weidner, Tobias; Breen, Nicholas F.; Li, Kun; Drobny, Gary P.; Castner, David G.

    2010-01-01

    The power of combining sum frequency generation (SFG) vibrational spectroscopy and solid-state nuclear magnetic resonance (ssNMR) spectroscopy to quantify, with site specificity and atomic resolution, the orientation and dynamics of side chains in synthetic model peptides adsorbed onto polystyrene (PS) surfaces is demonstrated in this study. Although isotopic labeling has long been used in ssNMR studies to site-specifically probe the structure and dynamics of biomolecules, the potential of SFG to probe side chain orientation in isotopically labeled surface-adsorbed peptides and proteins remains largely unexplored. The 14 amino acid leucine-lysine peptide studied in this work is known to form an α-helical secondary structure at liquid-solid interfaces. Selective, individual deuteration of the isopropyl group in each leucine residue was used to probe the orientation and dynamics of each individual leucine side chain of LKα14 adsorbed onto PS. The selective isotopic labeling methods allowed SFG analysis to determine the orientations of individual side chains in adsorbed peptides. Side chain dynamics were obtained by fitting the deuterium ssNMR line shape to specific motional models. Through the combined use of SFG and ssNMR, the dynamic trends observed for individual side chains by ssNMR have been correlated with side chain orientation relative to the PS surface as determined by SFG. This combination provides a more complete and quantitative picture of the structure, orientation, and dynamics of these surface-adsorbed peptides than could be obtained if either technique were used separately. PMID:20628016

  2. Amplification of trace amounts of nucleic acids

    DOEpatents

    Church, George M [Brookline, MA; Zhang, Kun [Brighton, MA

    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).

  3. 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. Copyright © 2015 Elsevier B.V. All rights reserved.

  4. 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) Amore » 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.« less

  5. Shock compression and flash-heating of molecular adsorbates on the picosecond time scale

    NASA Astrophysics Data System (ADS)

    Berg, Christopher Michael

    An ultrafast nonlinear coherent laser spectroscopy termed broadband multiplex vibrational sum-frequency generation (SFG) with nonresonant suppression was employed to monitor vibrational transitions of molecular adsorbates on metallic substrates during laser-driven shock compression and flash-heating. Adsorbates were in the form of well-ordered self-assembled monolayers (SAMs) and included molecular explosive simulants, such as nitroaromatics, and long chain-length alkanethiols. Based on reflectance measurements of the metallic substrates, femtosecond flash-heating pulses were capable of producing large-amplitude temperature jumps with DeltaT = 500 K. Laser-driven shock compression of SAMs produced pressures up to 2 GPa, where 1 GPa ≈ 1 x 104 atm. Shock pressures were estimated via comparison with frequency shifts observed in the monolayer vibrational transitions during hydrostatic pressure measurements in a SiC anvil cell. Molecular dynamics during flash-heating and shock loading were probed with vibrational SFG spectroscopy with picosecond temporal resolution and sub-nanometer spatial resolution. Flash-heating studies of 4-nitrobenzenethiolate (NBT) on Au provided insight into effects from hot-electron excitation of the molecular adsorbates at early pump-probe delay times. At longer delay times, effects from the excitation of SAM lattice modes and lower-energy NBT vibrations were shown. In addition, flash-heating studies of alkanethiolates demonstrated chain disordering behaviors as well as interface thermal conductances across the Au-SAM junction, which was of specific interest within the context of molecular electronics. Shock compression studies of molecular explosive simulants, such as 4-nitrobenzoate (NBA), demonstrated the proficiency of this technique to observe shock-induced molecular dynamics, in this case orientational dynamics, on the picosecond time scale. Results validated the utilization of these refined shock loading techniques to probe the shock

  6. Food wastes derived adsorbents for carbon dioxide and benzene gas sorption.

    PubMed

    Opatokun, Suraj Adebayo; Prabhu, Azhagapillai; Al Shoaibi, Ahmed; Srinivasakannan, C; Strezov, Vladimir

    2017-02-01

    Food wastes are produced worldwide in large quantities that could have potential to produce higher value products, including industrial adsorbents. The present work attempts valorization of food waste by CO 2 activation and functionalization through nitric acid and melamine treatment. The prepared porous materials were subjected to gas phase adsorption of CO 2 and benzene gases. The resultant highly porous carbon materials with surface area range from 797 to 1025 m 2 /g were synthesized showing uptake capacities of 4.41, 4.07, 4.18 and 4.36 mmol/g of CO 2 and 345, 305, 242.5 and 380.7 mg/g of C 6 H 6 respectively for PyF515, PyF520, PyF715 and PyF720 in the absence of doped carbon matrix. Differential thermogravimetric (DTG) analysis showed the thermostability of the precursors to validate selected initial pyrolysis temperatures (500 and 700 °C). C 6 H 6 sorption lies mainly in the physisorption region for all adsorbents ensuring re-generation potential. PyF720 and PyF520 recorded the highest isosteric enthalpy of 64.4 kJ/mol and 48.7 kJ/mol respectively, despite the low degree of coverage of the latter. Thus, PyF515 and PyF720 demonstrated the potential for use as sustainable and cost effective adsorbents for benzene gas containment suitable for swing adsorption system. Copyright © 2016 Elsevier Ltd. All rights reserved.

  7. Photoemission into water adsorbed on metals: Probing dissociative electron transfer using theory

    NASA Astrophysics Data System (ADS)

    Zhang, Yu; Whitten, J. L.

    The photoinduced dissociation of water adsorbed on a silver nanoparticle is explored using theory to probe reaction pathways that produce hydrogen. Ab initio configuration theory is used to describe the systems. A formulation that allows excited electronic states embedded in a near continuum of lower energy states to be calculated accurately is described. Electron attachment of a photoemitted electron to adsorbed water can lead to the formation of H2 at a very low energy barrier with oxygen remaining on the Ag surface. A large energy barrier to form H2 plus adsorbed O is found for the ground state. The excited state has a much smaller barrier to OH stretch; however, to dissociate, the system must cross over from the excited state to the ground state potential energy surface. The cross over point is near the transition state for a ground state process. A characteristic feature of the excited state potential curve is an increase in energy in the early stages of OH stretch as the charge transfer state evolves from a state with considerable Rydberg character to one that has a typical OH antibonding molecular orbital. Another pathway releases a H atom leaving OH on the surface. Effects due to doping of a Ag nanoparticle with a K electron donor atom are compared with those caused by a Fermi level shift due to an applied potential. Results are also reported for electron transfer to a solvated lithium ion, Li(H2O) 6+, near the surface of a silver particle. A steering mechanism is found that involves the interaction of a hydridic hydrogen formed after electron transfer with an acidic hydrogen of a second solvated water molecule.

  8. Charge-transfer excited state in pyrene-1-carboxylic acids adsorbed on titanium dioxide nanoparticles

    NASA Astrophysics Data System (ADS)

    Krawczyk, S.; Nawrocka, A.; Zdyb, A.

    2018-06-01

    The electronic structure of excited photosensitizer adsorbed at the surface of a solid is the key factor in the electron transfer processes that underlie the efficiency of dye-sensitized solar cells and photocatalysts. In this work, Stark effect (electroabsorption) spectroscopy has been used to measure the polarizability and dipole moment changes in electronic transitions of pyrene-1-carboxylic (PCA), -acetic (PAA) and -butyric (PBA) acids in ethanol, both free and adsorbed on colloidal TiO2, in glassy ethanol at low temperature. The lack of appreciable increase of dipole moment in the excited state of free and adsorbed PAA and PBA points that two or more single bonds completely prevent the expansion of π-electrons from the aromatic ring towards the carboxylic group, thus excluding the possibility of direct electron injection into TiO2. In free PCA, the pyrene's forbidden S0 → S1 transition has increased intensity, exhibits a long progression in 1400 cm-1 Ag mode and is associated with |Δμ| of 2 D. Adsorption of PCA on TiO2 causes a broadening and red shift of the S0 → S1 absorption band and an increase in dipole moment change on electronic excitation to |Δμ| = 6.5 D. This value increased further to about 15 D when the content of acetic acid in the colloid was changed from 0.2% to 2%, and this effect is ascribed to the surface electric field. The large increase of |Δμ| points that the electric field effect can not only change the energetics of electron transfer from the excited sensitizer into the solid, but can also shift the molecular electronic density, thus directly influencing the electronic coupling factor relevant for electron transfer at the molecule-solid interface.

  9. 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. © The Author(s) 2014.

  10. Monitoring and Control of an Adsorption System Using Electrical Properties of the Adsorbent for Organic Compound Abatement.

    PubMed

    Hu, Ming-Ming; Emamipour, Hamidreza; Johnsen, David L; Rood, Mark J; Song, Linhua; Zhang, Zailong

    2017-07-05

    Adsorption systems typically need gas and temperature sensors to monitor their adsorption/regeneration cycles to separate gases from gas streams. Activated carbon fiber cloth (ACFC)-electrothermal swing adsorption (ESA) is an adsorption system that has the potential to be controlled with the electrical properties of the adsorbent and is studied here to monitor and control the adsorption/regeneration cycles without the use of gas and temperature sensors and to predict breakthrough before it occurs. The ACFC's electrical resistance was characterized on the basis of the amount of adsorbed organic gas/vapor and the adsorbent temperature. These relationships were then used to develop control logic to monitor and control ESA cycles on the basis of measured resistance and applied power values. Continuous sets of adsorption and regeneration cycles were performed sequentially entirely on the basis of remote electrical measurements and achieved ≥95% capture efficiency at inlet concentrations of 2000 and 4000 ppm v for isobutane, acetone, and toluene in dry and elevated relative humidity gas streams, demonstrating a novel cyclic ESA system that does not require gas or temperature sensors. This contribution is important because it reduces the cost and simplifies the system, predicts breakthrough before its occurrence, and reduces emissions to the atmosphere.

  11. First-principles configurational thermodynamics of alloyed nanoparticles with adsorbates

    NASA Astrophysics Data System (ADS)

    Wang, Lin-Lin; Tan, Teck L.; Johnson, Duane D.

    2014-03-01

    Transition-metal, alloyed nanoparticles (NPs) are key components in current and emerging energy technologies because they are found to improve catalytic activity and selectivity for many energy-conversion processes. However, thermodynamic investigations of the compositional profile of alloyed nanoparticles, which determines their catalytic properties, have been limited mostly to NP core-shell preference without the presence of adsorbates. Here, by extending cluster expansion methods to treat both alloyed nanoparticles and adsorbates, we study the configurational thermodynamics of bimetallic NPs under chemically reactive conditions, using databases from density functional theory calculations. With a few examples, we show that such simulations can provide information needed for rational design of NP catalysts. DOE/BES under DE-FG02-03ER15476 (Catalysis) and DE-AC02-07CH11358 at the Ames Laboratory.

  12. Radiolysis of alanine adsorbed in a clay mineral

    SciTech Connect

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

    2013-07-03

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

  13. Nanoalloy electrocatalysis: simulating cyclic voltammetry from configurational thermodynamics with adsorbates.

    PubMed

    Wang, Lin-Lin; Tan, Teck L; Johnson, Duane D

    2015-11-14

    We simulate the adsorption isotherms for alloyed nanoparticles (nanoalloys) with adsorbates to determine cyclic voltammetry (CV) during electrocatalysis. The effect of alloying on nanoparticle adsorption isotherms is provided by a hybrid-ensemble Monte Carlo simulation that uses the cluster expansion method extended to non-exchangeable coupled lattices for nanoalloys with adsorbates. Exemplified here for the hydrogen evolution reaction, a 2-dimensional CV is mapped for Pd-Pt nanoalloys as a function of both electrochemical potential and the global Pt composition, and shows a highly non-linear alloying effect on CV. Detailed features in CV arise from the interplay among the H-adsorption in multiple sites that is closely correlated with alloy configurations, which are in turn affected by the H-coverage. The origins of specific features in CV curves are assigned. The method provides a more complete means to design nanoalloys for electrocatalysis.

  14. Nanoalloy electrocatalysis: Simulating cyclic voltammetry from configurational thermodynamics with adsorbates

    SciTech Connect

    Wang, Lin -Lin; Tan, Teck L.; Johnson, Duane D.

    2015-02-27

    We simulate the adsorption isotherms for alloyed nanoparticles (nanoalloys) with adsorbates to determine cyclic voltammetry (CV) during electrocatalysis. The effect of alloying on nanoparticle adsorption isotherms is provided by a hybrid-ensemble Monte Carlo simulation that uses the cluster expansion method extended to non-exchangeable coupled lattices for nanoalloys with adsorbates. Exemplified here for the hydrogen evolution reaction, a 2-dimensional CV is mapped for Pd–Pt nanoalloys as a function of both electrochemical potential and the global Pt composition, and shows a highly non-linear alloying effect on CV. Detailed features in CV arise from the interplay among the H-adsorption in multiple sites thatmore » is closely correlated with alloy configurations, which are in turn affected by the H-coverage. The origins of specific features in CV curves are assigned. As a result, the method provides a more complete means to design nanoalloys for electrocatalysis.« less

  15. Development of the Molecular Adsorber Coating for Spacecraft and Instrument Interiors

    NASA Technical Reports Server (NTRS)

    Abraham, Nithin

    2011-01-01

    On-orbit Molecular Contamination occurs when materials outgas and deposit onto very sensitive interior surfaces of the spacecraft and instruments. The current solution, Molecular Adsorber Pucks, has disadvantages, which are reviewed. A new innovative solution, Molecular Adsorber Coating (MAC), is currently being formulated, optimized, and tested. It is a sprayable alternative composed of Zeolite-based coating with adsorbing properties.

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

    EPA Science Inventory

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

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

    DTIC Science & Technology

    1989-12-01

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

  18. Heat capacity of xenon adsorbed on nanobundle grooves

    NASA Astrophysics Data System (ADS)

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

    2016-02-01

    A model of a one-dimensional nonideal gas in an external transverse force field is used to interpret the experimentally observed thermodynamic properties of xenon deposited in grooves on the surface of carbon nanobundles. A nonideal gas model with pairwise interactions is not entirely adequate for describing dense adsorbates (at low temperatures), but makes it easy to account for the exchange of particles between the 1D adsorbate and the 3D atmosphere, which is an important factor at intermediate (on the order of 35 K for xenon) and, especially, high (˜100 K) temperatures. In this paper, we examine a 1D real gas taking only the one-dimensional Lennard-Jones interaction into account, but under exact equilibrium with respect to the number of particles between the 1D adsorbate and the 3D atmosphere of the measurement cell. The low-temperature branch of the specific heat is fitted independently by an elastic chain model so as to obtain the best agreement between theory and experiment over the widest possible region, beginning at zero temperature. The gas approximation sets in after temperatures for which the phonon specific heat of the chain essentially transforms to a one-dimensional equipartition law. Here the basic parameters of both models can be chosen so that the heat capacity C(T) of the chain transforms essentially continuously into the corresponding curve for the gas approximation. Thus, it can be expected that an adequate interpretation of the real temperature dependences of the specific heat of low-dimensionality atomic adsorbates can be obtained through a reasonable combination of the phonon and gas approximations. The main parameters of the gas approximation (such as the desorption energy) obtained by fitting the theory to experiments on the specific heat of xenon correlate well with published data.

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

    NASA Astrophysics Data System (ADS)

    Kobetičová, Hana; Galbičková, Blanka; Ševčíková, Janka; Soldán, Maroš

    2014-12-01

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

  20. A study of vibrating nanotubes with additional adsorbed masses

    NASA Astrophysics Data System (ADS)

    Adler, Joan; Adler, Omri

    2017-11-01

    We describe calculations of the electronic density surrounding strained nanotubes. These are then used to estimate the nanotube wall width. This width is an essential parameter for the analysis of the nanotube vibrations. By studying the effect of additional adsorbed molecules on the nanotubes’ vibrations and their frequency changes we can deduce the molecules’ mass. Our calculations show that the strain does not greatly affect the nanotube width, but the vibrations change sufficiently for the mass to be detected.

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

    SciTech Connect

    Park, Jiyeon; Jeters, Robert T.; Gill, Gary A.

    2015-10-01

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

  2. 48 CFR 970.5215-1 - Total available fee: Base fee amount and performance fee amount.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ..., Profit, and Other Incentives—Facility Management Contracts” if contained in the contract. (d) Performance... fee amount and performance fee amount. 970.5215-1 Section 970.5215-1 Federal Acquisition Regulations System DEPARTMENT OF ENERGY AGENCY SUPPLEMENTARY REGULATIONS DOE MANAGEMENT AND OPERATING CONTRACTS...

  3. Theory of raman scattering from molecules adsorbed at semiconductor surfaces

    NASA Astrophysics Data System (ADS)

    Ueba, H.

    1983-09-01

    A theory is presented to calculate the Raman polarizability of an adsorbed molecule at a semiconductor surface, where the electronic excitation in the molecular site interacts with excitons (elementary excitations in the semiconductor) through non-radiative energy transfer between them, in an intermediate state in the Raman scattering process. The Raman polarizability thus calculated is found to exhibit a peak at the energy corresponding to a resonant excitation of excitons, thereby suggesting the possibility of surface enhanced Raman scattering on semiconductor surfaces. The mechanism studied here can also give an explanation of a recent observation of the Raman excitation profiles of p-NDMA and p-DMAAB adsorbed on ZnO or TiO 2, where those profiles were best described by assuming a resonant intermediate state of the exciton transition in the semiconductors. It is also demonstrated that in addition to vibrational Raman scattering, excitonic Raman scattering of adsorbed molecules will occur in the coupled molecule-semiconductor system, where the molecular returns to its ground electronic state by leaving an exciton in the semiconductor. A spectrum of the excitonic Raman scattering is expected to appear in the background of the vibrational Raman band and to be characterized by the electronic structure of excitons. A desirable experiment is suggested for an examination of the theory.

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

    NASA Astrophysics Data System (ADS)

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

    2017-10-01

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

  5. Development Trends in Porous Adsorbents for Carbon Capture.

    PubMed

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

    2015-11-03

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

  6. Treatment of Refinery Waste Water Using Environmental Friendly Adsorbent

    NASA Astrophysics Data System (ADS)

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

    2017-12-01

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

  7. Evaluation of Adsorbed Arsenic and Potential Contribution to Shallow Groundwater in Tulare Lake Bed Area, Tulare Basin, California

    USGS Publications Warehouse

    Gao, S.; Fujii, R.; Chalmers, A.T.; Tanji, K.K.

    2004-01-01

    Elevated As concentrations in shallow groundwater in parts of the Tulare Basin, California, are a concern because of potential migration into deeper aquifers that could serve as a source of future drinking water. The objectives of this study were to evaluate adsorbed As and the potential contribution to groundwater using (i) isotopic dilution, (ii) successive extraction with an electrolyte solution resembling the pore-water chemical composition, and (iii) PO4 exchange for As. Sediment samples collected from 2 to 4 m below land surface in the Tulare Lake bed area contained a total As concentration of 24 mg As kg-1. Pore water extracted under hydraulic pressure contained a total As concentration of 590 ??g As L-1, which predominantly contained As as arsenate [As(V), 97%], a minor amount of arsenite [As(III), 3%], and non-detectable organic As. The isotopic dilution method [73As(V)] estimated that the concentration of adsorbed As(V) on the sediment was 5.7 mg As kg-1 at pH 8.5 and 6.7 mg As kg-1 at pH 7.5, respectively. Fourteen successive 24-h extractions with the artificial pore water released up to 57 to 61% of the adsorbed As(V) that was determined by isotopic dilution, indicating that only a portion of the adsorbed As could be released to groundwater. The phosphate-exchangeable As (0.1 M PO4, pH 8.5 or 7.5) was 63% of the isotopically exchangeable As(V). Thus, extraction of As by 0.1 M PO4 at ambient pHs is recommended as a method to determine the potential amount of As(V) on sediments that could be released to the solution phase. The overall results indicated that adsorbed As could be a significant source of As to groundwater. However, other factors that affect As transport such as the leaching rate need to be considered.

  8. Forest amount affects soybean productivity in Brazilian agricultural frontier

    NASA Astrophysics Data System (ADS)

    Rattis, L.; Brando, P. M.; Marques, E. Q.; Queiroz, N.; Silverio, D. V.; Macedo, M.; Coe, M. T.

    2017-12-01

    Over the past three decades, large tracts of tropical forests have been converted to crop and pasturelands across southern Amazonia, largely to meet the increasing worldwide demand for protein. As the world's population continue to grow and consume more protein per capita, forest conversion to grow more crops could be a potential solution to meet such demand. However, widespread deforestation is expected to negatively affect crop productivity via multiple pathways (e.g., thermal regulation, rainfall, local moisture, pest control, among others). To quantify how deforestation affects crop productivity, we modeled the relationship between forest amount and enhanced vegetation index (EVI—a proxy for crop productivity) during the soybean planting season across southern Amazonia. Our hypothesis that forest amount causes increased crop productivity received strong support. We found that the maximum MODIS-based EVI in soybean fields increased as a function of forest amount across three spatial-scales, 0.5 km, 1 km, 2 km, 5 km, 10 km, 15 km and 20 km. However, the strength of this relationship varied across years and with precipitation, but only at the local scale (e.g., 500 meters and 1 km radius). Our results highlight the importance of considering forests to design sustainable landscapes.

  9. The role of adsorbed water on the friction of a layer of submicron particles

    USGS Publications Warehouse

    Sammis, Charles G.; Lockner, David A.; Reches, Ze’ev

    2011-01-01

    Anomalously low values of friction observed in layers of submicron particles deformed in simple shear at high slip velocities are explained as the consequence of a one nanometer thick layer of water adsorbed on the particles. The observed transition from normal friction with an apparent coefficient near μ = 0.6 at low slip speeds to a coefficient near μ = 0.3 at higher slip speeds is attributed to competition between the time required to extrude the water layer from between neighboring particles in a force chain and the average lifetime of the chain. At low slip speeds the time required for extrusion is less than the average lifetime of a chain so the particles make contact and lock. As slip speed increases, the average lifetime of a chain decreases until it is less than the extrusion time and the particles in a force chain never come into direct contact. If the adsorbed water layer enables the otherwise rough particles to rotate, the coefficient of friction will drop to μ = 0.3, appropriate for rotating spheres. At the highest slip speeds particle temperatures rise above 100°C, the water layer vaporizes, the particles contact and lock, and the coefficient of friction rises to μ = 0.6. The observed onset of weakening at slip speeds near 0.001 m/s is consistent with the measured viscosity of a 1 nm thick layer of adsorbed water, with a minimum particle radius of approximately 20 nm, and with reasonable assumptions about the distribution of force chains guided by experimental observation. The reduction of friction and the range of velocities over which it occurs decrease with increasing normal stress, as predicted by the model. Moreover, the analysis predicts that this high-speed weakening mechanism should operate only for particles with radii smaller than approximately 1 μm. For larger particles the slip speed required for weakening is so large that frictional heating will evaporate the adsorbed water and weakening will not occur.

  10. Comparing dissolved reactive phosphorus measured by DGT with ferrihydrite and titanium dioxide adsorbents: anionic interferences, adsorbent capacity and deployment time.

    PubMed

    Panther, Jared G; Teasdale, Peter R; Bennett, William W; Welsh, David T; Zhao, Huijun

    2011-07-18

    Two adsorbents (Metsorb and ferrihydrite) used in binding layers with the diffusive gradients in a thin film technique were evaluated for the measurement of dissolved reactive phosphorous (DRP) in synthetic and natural waters. Possible interferences were investigated with Cl(-) (up to 1.35 mol L(-1)) and SO(4)(2-) (up to 0.056 mol L(-1)) having no affect on either DGT binding layer, and HCO(3)(-) (up to 5.7 mmol L(-1)) having no effect on Metsorb-DGT, over 4 days. However, HCO(3)(-) interfered with the ferrihydrite-DGT measurement at concentrations typical of many natural waters (≥0.7 mmol L(-1)) after a deployment period of 1-2 days. The capacity of the Metsorb binding phase for DGT response was ∼37,000 ng P, whereas the capacities of a low-mass (17.8 mg of adsorbent per DGT sampler) and high-mass (29.2mg of adsorbent per DGT sampler) ferrihydrite binding phase were substantially lower (∼15,000 ng P and ∼25,000 ng P, low-mass and high-mass, respectively). Increasing the capacity of the ferrihydrite adsorbent allowed the ferrihydrite-DGT to be utilized for up to 3 days before interference by HCO(3)(-) was observed. Seawater deployments demonstrated that even high-capacity ferrihydrite-DGT devices underestimated the DRP concentration by 37%, whereas Metsorb-DGT measurements were accurate. The Metsorb-DGT is superior to the ferrihydrite-DGT for determining DRP over deployment times greater than 1 day and in waters with ≥0.7 mmol L(-1) HCO(3)(-). Based on the experience obtained from this detailed validation process, the authors propose a number of key requirements that need to be considered when developing new DGT binding layers, with testing the performance over longer deployment times being critical. Copyright © 2011 Elsevier B.V. All rights reserved.

  11. Three-dimensionally porous graphene: A high-performance adsorbent for removal of albumin-bonded bilirubin.

    PubMed

    Ma, Chun Fang; Gao, Qiang; Xia, Kai Sheng; Huang, Zhi Yuan; Han, Bo; Zhou, Cheng Gang

    2017-01-01

    The development of bilirubin adsorbents with high adsorption efficiencies towards albumin-bonded bilirubin is still a considerable challenge. In this work, a three-dimensionally porous graphene (3D-pGR) has been fabricated through a simple carbon dioxide (CO 2 ) activation of thermally exfoliated graphite oxide (EGO). Intriguingly, the resultant 3D-pGR material showed hierarchically micro-meso-macroporous structure, high specific surface area of up to 843m 2 g -1 , and large pore volume as high as 2.71cm 3 g -1 . Besides, the large planar π-configuration structure of 3D-pGR made it possible to compete effectively with albumin for bilirubin binding. Taking advantages of these fantastic characteristics, the 3D-pGR was demonstrated to be extraordinarily efficient for bilirubin removal from a bovine serum albumin (BSA)-rich solution. Under optimized conditions, the maximum adsorption capacity of 3D-pGR for BSA-bonded bilirubin was up to 126.1mgg -1 , which is not only significantly higher than the adsorption capacities of currently available adsorbents towards albumin-bonded bilirubin, but also superior to those of many reported adsorbents towards free bilirubin. In addition, the hemolysis assay of 3D-pGR indicated that this material had negligible hemolysis effect. Findings from this study may open up important new possibilities for removal of protein-bonded toxins. Copyright © 2016 Elsevier B.V. All rights reserved.

  12. Spinel type CoFe oxide porous nanosheets as magnetic adsorbents with fast removal ability and facile separation.

    PubMed

    Ge, X; Gu, C D; Wang, X L; Tu, J P

    2015-09-15

    Adsorption is often time consuming due to slow diffusion kinetic. Sizing he adsorbent down might help to accelerate adsorption. For CoFe spinel oxide, a magnetically separable adsorbent, the preparation of nanosheets faces many challenges including phase separation, grain growth and difficulty in preparing two-dimensional materials. In this work, we prepared porous CoFe oxide nanosheet with chemical formula of Co2.698Fe0.302O4 through topochemical transformation of a CoFe precursor, which has a layered double hydroxide (LDH) analogue structure and a large interlayer spacing. The LDH precursor was synthesized from a cheap deep eutectic solvent (DES) system. The calcined Co2.698Fe0.302O4 has small grain size (10-20nm), nanosheet morphology, and porous structure, which contribute to a large specific surface area of 79.5m(2)g(-1). The Co2.698Fe0.302O4 nanosheets show fast removal ability and good adsorption capacity for both organic waste (305mgg(-1) in 5min for Congo red) and toxic heavy metal ion (5.27mgg(-1) in 30min for Cr (VI)). Furthermore, the Co2.698Fe0.302O4 can be separated magnetically. Considering the precursor can be prepared through a fast, simple, surfactant-free and high-yield synthetic strategy, this work should have practical significance in fabricating adsorbents. Copyright © 2015 Elsevier Inc. All rights reserved.

  13. Poultry manure as raw material for mercury adsorbents in gas applications

    SciTech Connect

    Klasson, K.T.; Lima, I.M.; Boihem, L.L.

    2009-09-30

    The quantity of poultry manure generated each year is large, and technologies that take advantage of the material should be explored. At the same time, increased emphasis on the reduction of mercury emissions from coal-fired electric power plants has 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 they could adsorb the mercury. The sorbents (now containing mercury) would be removed via filtration or other means from the flue gas. Our preliminary work has demonstrated that activated carbon made from poultrymore » manure can adsorb mercury from air with good efficiency. In laboratory experiments, an activated carbon made from turkey cake manure removed the majority of elemental mercury from a hot air stream. Other activated carbons made from chicken and turkey litter manure were also efficient. In general, unwashed activated carbons made from poultry manure were more efficient in removing mercury than their acid-washed counterparts. The results suggest that the adsorption of mercury was mainly due to chemisorption on the surface of the carbon. Other potential uses for the activated carbons are the removal of mercury from air and natural gas.« less

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

    PubMed

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

    2016-07-04

    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. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  15. Advanced wide-field surface plasmon microscopy of single adsorbing nanoparticles

    NASA Astrophysics Data System (ADS)

    Nizamov, Shavkat; Scherbahn, Vitali; Mirsky, Vladimir M.

    2017-05-01

    In-situ detection and characterization of nanoparticles in biological media as well as in food or other complex samples is still a big challenge for existing analytical methods. Here we describe a label-free and cost-effective analytical method for detection of nanoparticles in the concentration range 106 -1010 NPs/ml. The proposed method is based on the surface plasmon resonance microscopy (SPRM) with a large field of view ( 1.3mm2 ). It is able to detect and count adsorbing nanoparticles individually, totally up to the hundreds of thousands of NPs on the sensor surface. At constant diffusion conditions the detection rate is proportional to the number concentration of NPs, this provides an approach to determine the NPs concentration. The adsorption of nanoparticle can be manipulated by the surface functionalization, pH and electrolyte concentration of suspensions. Images of detected nanoparticles can be quantified in order to characterize them individually. The image intensity grows quasi-linearly with nanoparticle size for the given material. However, the size and material of nanoparticle cannot be resolved directly from the image. For determination of chemical composition, SPRM can be assisted by electrochemical analysis. In this case, the gold sensor surface is used both as a resonant media for plasmon microscopy and as a working electrode. Under potential sweep, the adsorbed NPs can be subjected to electrochemical dissolution, which is detected optically. The potential of this conversion characterizes the material of NPs.

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

    DOEpatents

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

    2016-05-03

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

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

    DOEpatents

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

    2015-06-02

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

  18. 29 CFR 4219.14 - Amount of liability for 20-year-limitation amounts.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... amount equal to the present value of all initial withdrawal liability payments for which the employer was not liable pursuant to section 4219(c)(1)(B) of ERISA. The present value of such payments shall be...

  19. Carbon coated magnetic nanoparticles as a novel magnetic solid phase extraction adsorbent for simultaneous extraction of methamphetamine and ephedrine from urine samples.

    PubMed

    Taghvimi, Arezou; Hamishehkar, Hamed

    2017-01-15

    This paper develops a highly selective, specific and efficient method for simultaneous determination of ephedrine and methamphetamine by a new carbon coated magnetic nanoparticles (C/MNPs) as a magnetic solid phase extraction (MSPE) adsorbent in biological urine medium. The characterization of synthesized magnetic nano adsorbent was completely carried out by various characterization techniques like Fourier transform infrared (FT-IR) spectroscopy, powder x-ray diffraction (XRD), scanning electron microscopy (SEM) and vibrating sample magnetometer (VSM). Nine important parameters influencing extraction efficiency including amount of adsorbent, amounts of sample volume, pH, type and amount of extraction organic solvent, time of extraction and desorption, agitation rate and ionic strength of extraction medium, were studied and optimized. Under optimized extraction conditions, a good linearity was observed in the concentration range of 100-2000ng/mL for ephedrine and 100-2500ng/mL for methamphetamine. Analysis of positive urine samples was carried out by proposed method with the recovery of 98.71 and 97.87% for ephedrine and methamphetamine, respectively. The results indicated that carbon coated magnetic nanoparticles could be applied in clinical and forensic laboratories for simultaneous determination of abused drugs in urine media. Copyright © 2016 Elsevier B.V. All rights reserved.

  20. Application of advanced sampling and analysis methods to predict the structure of adsorbed protein on a material surface

    PubMed Central

    Abramyan, Tigran M.; Hyde-Volpe, David L.; Stuart, Steven J.; Latour, Robert A.

    2017-01-01

    The use of standard molecular dynamics simulation methods to predict the interactions of a protein with a material surface have the inherent limitations of lacking the ability to determine the most likely conformations and orientations of the adsorbed protein on the surface and to determine the level of convergence attained by the simulation. In addition, standard mixing rules are typically applied to combine the nonbonded force field parameters of the solution and solid phases the system to represent interfacial behavior without validation. As a means to circumvent these problems, the authors demonstrate the application of an efficient advanced sampling method (TIGER2A) for the simulation of the adsorption of hen egg-white lysozyme on a crystalline (110) high-density polyethylene surface plane. Simulations are conducted to generate a Boltzmann-weighted ensemble of sampled states using force field parameters that were validated to represent interfacial behavior for this system. The resulting ensembles of sampled states were then analyzed using an in-house-developed cluster analysis method to predict the most probable orientations and conformations of the protein on the surface based on the amount of sampling performed, from which free energy differences between the adsorbed states were able to be calculated. In addition, by conducting two independent sets of TIGER2A simulations combined with cluster analyses, the authors demonstrate a method to estimate the degree of convergence achieved for a given amount of sampling. The results from these simulations demonstrate that these methods enable the most probable orientations and conformations of an adsorbed protein to be predicted and that the use of our validated interfacial force field parameter set provides closer agreement to available experimental results compared to using standard CHARMM force field parameterization to represent molecular behavior at the interface. PMID:28514864

  1. Effects of surface imperfections on the binding of CH 3OH and H 2O on FeS 2(100): using adsorbed Xe as a probe of mineral surface structure

    NASA Astrophysics Data System (ADS)

    Guevremont, J. M.; Strongin, D. R.; Schoonen, M. A. A.

    1997-11-01

    Studies are presented that investigate the adsorption and binding of CH 3OH and H 2O on the atomically clean (100) crystallographic plane of pyrite, FeS 2. Temperature programmed desorption suggests that both reactants adsorb molecularly at 90 K and desorb thermally between 170 and 400 K depending on the surface coverage. Photoemission of adsorbed xenon (PAX) suggests that the surface of pyrite is heterogeneous and contains a significant fraction of defect sites that are believed to be, at least in part, anion vacancy or sulfur-deficient sites. An upper limit of 0.2 is proposed for the fraction of surface sites that are defects on FeS 2(100). PAX indicates that these defect sites at low adsorbate coverage serve as the exclusive binding sites for H 2O and CH 3OH adsorbate. We speculate, on the basis of our ability to interpret PAX data for pyrite, that PAX may be of use for understanding the effect of short range order on adsorbate binding on other complex mineral surfaces. On the basis of high resolution electron energy loss spectroscopy, it is found that some dissociation of the adsorbate occurs on the pyrite. Vibrational data obtained with this technique suggests that FeO species result from the adsorbate decomposition. After saturation of the defect sites, further molecular adsorption is accommodated on the less reactive surface that we postulate is largely disulfide, the characteristic structural group of pyrite.

  2. The application of reused powdered wastes as adsorbent for treating arsenic containing mine drainage.

    PubMed

    Park, Youn-Jong; Yang, Jae-Kyu; Choi, Sang-Il

    2008-07-15

    This study examined the potential reuse of powdered wastes (PW) generated during the sanding and sawing process in a local chemical company in Korea with the viewpoint of the recycling these wastes and minimizing the level of contamination. The PW contained 40-60% aluminum hydroxide and 30-45% matrix resin. As a potential adsorbent, the suitability of thermal treated PW to remove arsenic from synthetic and real wastewater was investigated. As a pretreatment process, the reused adsorbent from PW was calcined at 550 degrees C for 3 hrs in a furnace. The calcination characteristics of PW were examined both quantitatively and qualitatively by X-ray fluorescence (XRF), and qualitatively by X-ray diffraction (XRD). The major inorganic composition of the calcined PW (CPW) was aluminum oxide with poor crystallinity. The CPW contained well developed meso-pores (0.143 cm(3) g(-1)) and showed a specific surface area of 234 m(2) g(-1). The pH of the zero point charge (pH(pzc)) of the CPW was determined to be 7.8 by acid-base titration. From the batch adsorption tests, the complete removal of arsenic (up to 20 mg L(-1)) was observed with CPW (2 g) at pH ranging from 3.0 to 8.0. However, there was a significant decrease in arsenate adsorption at higher pH. A kinetics study indicated that the uptake of arsenate followed a second-order rate equation. In the presence of sulfate, the removal of arsenate was increasingly affected by the sulfate concentration. The application of CPW to the removal of 4 different real mine drainages was also carried out. Mine drainage contains a relatively high arsenate concentration as well as sulfate. Whilst the amount of arsenic removed from real mine drainage by CPW was slightly lower than that removed from synthetic wastewater due to competitive sorption by multiple ions, the adsorption of arsenate showed rapid removal within 10 min with good removal efficiency, which meets the national wastewater discharge limits. These results suggest that CPW

  3. Extraction of triazole fungicides in environmental waters utilizing poly (ionic liquid)-functionalized magnetic adsorbent.

    PubMed

    Liu, Cheng; Liao, Yingmin; Huang, Xiaojia

    2017-11-17

    This work prepared a new poly (ionic liquid)-functionalized magnetic adsorbent (PFMA) for the extraction of triazole fungicides (TFs) in environmental waters prior to determination by high performance liquid chromatography/diode array detection (HPLC-DAD). A polymerizable ionic liquid, 1-methyl-3-allylimidazolium bis(trifluoromethylsulfonyl)imide was employed to copolymerize with divinylbenzene on the surface of modified magnetite to fabricate the PFMA. The morphology, spectroscopic and magnetic properties of the new adsorbent were investigated by different techniques. A series of key parameters that influence the extraction performance including the amount of PFMA, desorption solvent, adsorption and desorption time, sample pH value and ionic strength were optimized in detail. Under the optimum conditions, the prepared PFMA could extract targeted TFs effectively and quickly under the format of magnetic solid-phase extraction (MSPE). Satisfactory linearities were achieved in the range of 0.1-200.0μg/L for triadimenol and 0.05-200.0μg/L for other TFs with good coefficients of determination above 0.99 for all analytes. The limits of detection (S/N=3) and limits of quantification (S/N=10) for TFs were in the range of 0.0050-0.0078μg/L and 0.017-0.026μg/L, respectively. Environmental waters including lake, river and well waters were used to demonstrate the applicability of developed MSPE-HPLC-DAD method, and satisfactory recoveries and repeatability were obtained. Copyright © 2017 Elsevier B.V. All rights reserved.

  4. Lake Water Quality Improvement by Using Waste Mussel Shell Powder as an Adsorbent

    NASA Astrophysics Data System (ADS)

    Zukri, N. I.; Khamidun, M. H.; Sapiren, M. S.; Abdullah, S.; Rahman, M. A. A.

    2018-04-01

    Lake water in UTHM was slightly greenish in color indicating the eutrophication process. Eutrophication problem is due to excessive amount of nutrient in the lake water which causes nuisance growth of algae and other aquatic plant. The improvement of lake water quality should be conducted wisely in preventing from eutrophication problem by using a suitable water treatment method. Natural materials, agricultural wastes and industrial wastes are locally available sources can be utilized as low-cost adsorbents. The natural abundant source of waste mussel’s shells is advantages to use as basis material to produce the low cost adsorbent for water treatment. Batch experiments were carried out with the preparation 500 ml volume of lake water sample with the dosage of 2.5g, 7.5g and 12.5g. Then the solution shaking in an incubator with 200 rpm shaking speed. The various dosage of mussel shell greatly affected pollutants removal. Both of NH4+ and PO43- have a higher percentage removal with 31.28% and 21.74% at the 7.5g of sample dosage. Other parameters such as COD and TSS also shown good percentage of removal at 7.5g of dosage sample with 44.45% and 25% respectively. While, dosage at 2.5g was performed as a good adsorption capacity of NH4+, PO43-, COD and TSS as high as 0.142, 0.234, 7.6 and 20 mg/g, respectively. These experimental results suggested that the use of mussel shell powder as good basis material in removing pollutants from lake water.

  5. Development of a cost-effective CO2 adsorbent from petroleum coke via KOH activation

    NASA Astrophysics Data System (ADS)

    Jang, Eunji; Choi, Seung Wan; Hong, Seok-Min; Shin, Sangcheol; Lee, Ki Bong

    2018-01-01

    The capture of CO2 via adsorption is considered an effective technology for decreasing global warming issues; hence, adsorbents for CO2 capture have been actively developed. Taking into account cost-effectiveness and environmental concerns, the development of CO2 adsorbents from waste materials is attracting considerable attention. In this study, petroleum coke (PC), which is the carbon residue remaining after heavy oil upgrading, was used to produce high-value-added porous carbon for CO2 capture. Porous carbon materials were prepared by KOH activation using different weight ratios of KOH/PC (1:1, 2:1, 3:1, and 4:1) and activation temperatures (600, 700, and 800 °C). The specific surface area and total pore volume of resulting porous carbon materials increased with KOH amount, reaching up to 2433 m2/g and 1.11 cm3/g, respectively. The sample prepared under moderate conditions with a KOH/PC weight ratio of 2:1 and activation temperature of 700 °C exhibited the highest CO2 adsorption uptake of 3.68 mmol/g at 25 °C and 1 bar. Interestingly, CO2 adsorption uptake was linearly correlated with the volume of micropores less than 0.8 nm, indicating that narrow micropore volume is crucial for CO2 adsorption. The prepared porous carbon materials also exhibited good selectivity for CO2 over N2, rapid adsorption, facile regeneration, and stable adsorption-desorption cyclic performance, demonstrating potential as a candidate for CO2 capture.

  6. Water and ion transport in ultra-adsorbing porous magnesium carbonate studied by dielectric spectroscopy

    NASA Astrophysics Data System (ADS)

    Pochard, Isabelle; Frykstrand, Sara; Ahlström, Olle; Forsgren, Johan; Strømme, Maria

    2014-01-01

    Porous materials are used in application areas ranging from drug and vaccine delivery, medical implants, molecular sieves and cosmetics to catalysis and humidity control. In the present work, we employed an alternative approach to gain in-depth understanding about water interaction properties in such materials by the use of dielectric spectroscopy and thereby show that it is possible to obtain information that is not accessible from the more commonly employed water interaction analysis techniques. Specifically, the complex dielectric response of Upsalite, a novel, super-hydroscopic, high-surface area, porous magnesium carbonate material was measured in isothermal frequency scans between 10-3 and 106 Hz at controlled relative humidity (RH). We found the dielectric constant of the dry material to be 1.82. The ratio of bound to free water present in Upsalite after adsorption at room temperature was found to be high irrespective of the surrounding humidity with values ranging from ˜67% to ˜90%. We further found that OH- ions are the charge carriers responsible for the electrode polarization observed in the dielectric response and that the amount of these ions that are free to move in the material corresponds to a concentration of the order of 1-10 μmol l-1 independent of RH. Finally, the OH- diffusion coefficient displayed a drastic decrease with decreasing RH, typical of transport in unsaturated conditions. The presented results provide detailed insight about water interactions in the novel water adsorbing material under study and it is foreseen that the employed analysis methods can be used to evaluate other types of moisture adsorbing materials as well as the movement of functional species in the pores of inorganic drug delivery materials and materials tailored for adsorption of harmful charged species.

  7. Preparation of activated carbon from waste plastics polyethylene terephthalate as adsorbent in natural gas storage

    NASA Astrophysics Data System (ADS)

    Yuliusman; Nasruddin; Sanal, A.; Bernama, A.; Haris, F.; Ramadhan, I. T.

    2017-02-01

    The main problem is the process of natural gas storage and distribution, because in normal conditions of natural gas in the gas phase causes the storage capacity be small and efficient to use. The technology is commonly used Compressed Natural Gas (CNG) and Liquefied Natural Gas (LNG). The weakness of this technology safety level is low because the requirement for high-pressure CNG (250 bar) and LNG requires a low temperature (-161°C). It takes innovation in the storage of natural gas using the technology ANG (Adsorbed Natural Gas) with activated carbon as an adsorbent, causing natural gas can be stored in a low pressure of about 34.5. In this research, preparation of activated carbon using waste plastic polyethylene terephthalate (PET). PET plastic waste is a good raw material for making activated carbon because of its availability and the price is a lot cheaper. Besides plastic PET has the appropriate characteristics as activated carbon raw material required for the storage of natural gas because the material is hard and has a high carbon content of about 62.5% wt. The process of making activated carbon done is carbonized at a temperature of 400 ° C and physical activation using CO2 gas at a temperature of 975 ° C. The parameters varied in the activation process is the flow rate of carbon dioxide and activation time. The results obtained in the carbonization process yield of 21.47%, while the yield on the activation process by 62%. At the optimum process conditions, the CO2 flow rate of 200 ml/min and the activation time of 240 minutes, the value % burn off amounted to 86.69% and a surface area of 1591.72 m2/g.

  8. Development of a membrane adsorber based capture step for the purification of yellow fever virus.

    PubMed

    Pato, Tânia P; Souza, Marta Cristina O; Silva, Andréa N M R; Pereira, Renata C; Silva, Marlon V; Caride, Elena; Gaspar, Luciane P; Freire, Marcos S; Castilho, Leda R

    2014-05-19

    Yellow fever (YF) is an endemic disease in some tropical areas of South America and Africa that presents lethality rate between 20 and 50%. There is no specific treatment and to control this disease a highly effective live-attenuated egg based vaccine is widely used for travelers and residents of areas where YF is endemic. However, recent reports of rare, sometimes fatal, adverse events post-vaccination have raised concerns. In order to increase safety records, alternative strategies should be considered, such as developing a new inactivated vaccine using a cell culture based technology, capable of meeting the demands in cases of epidemic. With this goal, the production of YF virus in Vero cells grown on microcarriers and its subsequent purification by chromatographic techniques was studied. In this work we investigate the capture step of the purification process of the YF virus. At first, virus stability was studied over a wide pH range, showing best results for the alkaline region. Considering this result and the pI of the envelope protein previously determined in silico, a strong anion exchanger was considered most suitable. Due to the easy scalability, simplicity to handle, absence of diffusional limitations and suitability for virus handling of membrane adsorbers, a Q membrane was evaluated. The amount of antigen adsorbed onto the membrane was investigated within the pH range for virus stability, and the best pH for virus adsorption was considered to be 8.5. Finally, studies on gradient and step elution allowed to determine the most adequate salt concentration for washing (0.15M) and virus elution (0.30 M). Under these operating conditions, it was shown that this capture step is quite efficient, showing high product recovery (93.2±30.3%) and efficient DNA clearance (0.9±0.3 ng/dose). Copyright © 2014 Elsevier Ltd. All rights reserved.

  9. Adsorption and structure of the adsorbed layer of ionic surfactants.

    PubMed

    Ivanov, Ivan B; Ananthapadmanabhan, Kavssery P; Lips, Alex

    2006-11-16

    Our goal in this study was to investigate theoretically and experimentally the adsorption of ionic surfactants and the role of different factors in the mechanism of adsorption, the adsorption parameters and the structure of the adsorbed layer. We used available literature data for the interfacial tension, sigma, vs. concentration, C(s), for sodium dodecyl sulfate (SDS) in three representative systems with Air/Water (A/W), Oil/Water (O/W) and Oil/Water + 0.1 M NaCl (O/WE) interfaces. We derived 6 new adsorption isotherms and 6 new equations of state (EOS) based on the adsorption isotherms for non-ionic surfactants of Langmuir, Volmer and Helfand-Frisch-Lebowitz (HFL) with interaction term betatheta2/2 in the EOS, theta=alphaGamma being the degree of coverage, with Gamma--adsorption and alpha--minimum area per molecule. We applied Gouy equation for high surface potentials and modified it to account for partial penetration of the counterions in the adsorbed layer. The equations were written in terms of the effective concentration C=[C(s)(C(s)+C(el))](1/2), where C(s) and C(el) are, respectively concentrations of the surfactant and the electrolyte. We showed that the adsorption constant K was model independent and derived an equation for the effective thickness of the adsorbed layer, delta(s). We found also that the minimum area per molecule, alpha, is larger than the true area, alpha(0), which depends on the adsorption model and is a function of the adsorption Gamma. The interaction term betatheta2/2 in the Langmuir EOS was found to be exact for small beta<1, but for the Volmer EOS it turned out to be only a crude approximation. Semi-quantitative considerations about the interaction between adsorbed discrete charges revealed that at A/W interface part of the adsorbed surfactant molecules are partially immersed in water, which leads to decreased repulsion and increased adsorption Gamma. At O/W the larger adsorption energy keeps the surfactant molecules on the surface

  10. Removal of sulfamethazine by hypercrosslinked adsorbents in aquatic systems.

    PubMed

    Grimmett, Maria E

    2013-01-01

    Four hundred tons of sulfamethazine are fed to livestock annually in North America to prevent disease and promote growth, but most of the drug is excreted unmetabolized into the environment. Because of slow degradation and high mobility, sulfamethazine contaminates groundwater supplies and causes aquatic ecosystem damage. Current water treatment methods to remove pharmaceuticals are not universally effective and have considerable limitations, which necessitate newer remediation techniques. Hypercrosslinked adsorbents, polystyrene polymers 100% crosslinked with methylene bridges, show promise because of high surface areas, high mechanical strength, and regenerable properties. This study screened four Purolite hypercrosslinked adsorbents (MN152, MN250, PAD400, and PAD600) to remove sulfamethazine from contaminated water and then characterized the most efficient resin, MN250, with batch adsorption and desorption experiments to optimize its use. Sulfamethazine adsorption onto MN250 displayed an L-class isotherm shape consistent with monolayer adsorption, negligible solute-solute interactions at the adsorbent surface, and decreasing activation energies of desorption with increasing surface coverage. MN250 had a maximum experimental adsorption capacity of 111 mg g, showing high correlation to the Langmuir and Freundlich models. Adsorption kinetics revealed prolonged adsorption over 59 h and were best described by Ho's pseudo-second-order model. There was minimal desorption from MN250 in distilled water, indicating an irreversible adsorption process. MN250's high capacity for sulfamethazine adsorption, minimal desorption in water, and ability to be regenerated make it a practical solution for sulfamethazine removal in areas that have contaminated groundwater supplies (e.g., areas near concentrated livestock operations), especially as current treatment methods have significant drawbacks. Copyright © by the American Society of Agronomy, Crop Science Society of America, and

  11. Adsorption equilibrium and dynamics of gasoline vapors onto polymeric adsorbents.

    PubMed

    Jia, Lijuan; Yu, Weihua; Long, Chao; Li, Aimin

    2014-03-01

    The emission of gasoline vapors is becoming a significant environmental problem especially for the population-dense area and also results in a significant economic loss. In this study, adsorption equilibrium and dynamics of gasoline vapors onto macroporous and hypercrosslinked polymeric resins at 308 K were investigated and compared with commercial activated carbon (NucharWV-A 1100). The results showed that the equilibrium and breakthrough adsorption capacities of virgin macroporous and hypercrosslinked polymeric resins were lower than virgin-activated carbon. Compared with origin adsorbents, however, the breakthrough adsorption capacities of the regenerated activated carbon for gasoline vapors decreased by 58.5 % and 61.3 % when the initial concentration of gasoline vapors were 700 and 1,400 mg/L, while those of macroporous and hypercrosslinked resins decreased by 17.4 % and 17.5 %, and 46.5 % and 45.5 %, respectively. Due to the specific bimodal property in the region of micropore (0.5-2.0 nm) and meso-macropore (30-70 nm), the regenerated hypercrosslinked polymeric resin exhibited the comparable breakthrough adsorption capacities with the regenerated activated carbon at the initial concentration of 700 mg/L, and even higher when the initial concentration of gasoline vapors was 1,400 mg/L. In addition, 90 % of relative humidity had ignorable effect on the adsorption of gasoline vapors on hypercrosslinked polymeric resin. Taken together, it is expected that hypercrosslinked polymeric adsorbent would be a promising adsorbent for the removal of gasoline vapors from gas streams.

  12. Improved of Natural Gas Storage with Adsorbed Natural Gas (ANG) Technology Using Activated Carbon from Plastic Waste Polyethylene Terepthalate

    NASA Astrophysics Data System (ADS)

    Yuliusman; Nasruddin; Sanal, A.; Bernama, A.; Haris, F.; Hardhi, M.

    2017-07-01

    Indonesia imports high amount of Fuel Oil. Although Indonesia has abundant amount of natural gas reserve, the obstacle lies within the process of natural gas storage itself. In order to create a safe repository, the ANG (Adsorbed Natural Gas) technology is planned. ANG technology in itself has been researched much to manufacture PET-based activated carbon for natural gas storage, but ANG still has several drawbacks. This study begins with making preparations for the equipment and materials that will be used, by characterizing the natural gas, measuring the empty volume, and degassing. The next step will be to examine the adsorption process. The maximum storage capacity obtained in this study for a temperature of 27°C and pressure of 35 bar is 0.0586 kg/kg, while for the desorption process, a maximum value for desorption efficiency was obtained on 35°C temperature with a value of 73.39%.

  13. STM observation of the chemical reaction of atomic hydrogen on the N-adsorbed Cu(001) surface

    NASA Astrophysics Data System (ADS)

    Hattori, Takuma; Yamada, Masamichi; Komori, Fumio

    2017-01-01

    Chemical reaction of atomic hydrogen with the N-adsorbed Cu(001) surfaces was investigated at room temperature by scanning tunnel microscopy. At the low exposure of atomic hydrogen, it reacted with the N atoms and turned to be the NH species on the surface. The reaction rate is proportional to the amount of the unreacted N atoms. By increasing the exposure of atomic hydrogen from this condition, the amount of nitrogen species on the surface decreased. This is attributed to the formation of ammonia and its desorption from the surface. The NH species on the surface turn to NH3 through the surface NH2 species by atomic hydrogen. Coexistence of the clean Cu surface enhances the rate of ammonia formation owing to atomic hydrogen migrating on the clean surface.

  14. Contaminant removal from enclosed atmospheres by regenerable adsorbents

    NASA Technical Reports Server (NTRS)

    Goldsmith, R. L.; Mcnulty, K. J.; Freedland, G. M.; Turk, A.; Nwankwo, J.

    1974-01-01

    A system for removing contaminants from spacecraft atmospheres was studied, which utilizes catalyst-impregnated activated carbon followed by in-situ regeneration by low-temperature catalytic oxidation of the adsorbed contaminants. Platinum was deposited on activated carbon by liquid phase impregnation with chloroplatinic acid, followed by drying and high-temperature reduction. Results were obtained for the seven selected spacecraft contaminants by means of three experimental test systems. The results indicate that the contaminants could be removed by oxidation with very little loss in adsorptive capacity. The advantages of a catalyst-impregnated carbon for oxidative regeneration are found to be significant enough to warrent its use.

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

    NASA Astrophysics Data System (ADS)

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

    2012-02-01

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

  16. Titanate-based adsorbents for radioactive ions entrapment from water.

    PubMed

    Yang, Dongjiang; Liu, Hongwei; Zheng, Zhanfeng; Sarina, Sarina; Zhu, Huaiyong

    2013-03-21

    This feature article reviews some titanate-based adsorbents for the removal of radioactive wastes (cations and anions) from water. At the beginning, we discuss the development of the conventional ion-exchangeable titanate powders for the entrapment of radioactive cations, such as crystalline silicotitanate (CST), monosodium titanate (MST), peroxotitanate (PT). Then, we specially emphasize the recent progress in the uptake of radioactive ions by one-dimensional (1D) sodium titanate nanofibers and nanotubes, which includes the synthesis and phase transformation of the 1D nanomaterials, adsorption ability (capacity, selectivity, kinetics, etc.) of radioactive cations and anions, and the structural evolution during the adsorption process.

  17. 3,5-Dichlorophenol Removal From Wastewater Using Alternative Adsorbents

    NASA Astrophysics Data System (ADS)

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

    2015-06-01

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

  18. Molecular switches from benzene derivatives adsorbed on metal surfaces

    PubMed Central

    Liu, Wei; Filimonov, Sergey N.; Carrasco, Javier; Tkatchenko, Alexandre

    2013-01-01

    Transient precursor states are often experimentally observed for molecules adsorbing on surfaces. However, such precursor states are typically rather short-lived, quickly yielding to more stable adsorption configurations. Here we employ first-principles calculations to systematically explore the interaction mechanism for benzene derivatives on metal surfaces, enabling us to selectively tune the stability and the barrier between two metastable adsorption states. In particular, in the case of the tetrachloropyrazine molecule, two equally stable adsorption states are identified with a moderate and conceivably reversible barrier between them. We address the feasibility of experimentally detecting the predicted bistable behaviour and discuss its potential usefulness in a molecular switch. PMID:24157660

  19. Behavior of adsorbed Poly-A onto sodium montmorillonite

    SciTech Connect

    Palomino-Aquino, Nayeli; Negrón-Mendoza, Alicia, E-mail: negron@nucleares.unam.mx

    2015-07-23

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

  20. Conformational Phase Diagram for Polymers Adsorbed on Ultrathin Nanowires

    NASA Astrophysics Data System (ADS)

    Vogel, Thomas; Bachmann, Michael

    2010-05-01

    We study the conformational behavior of a polymer adsorbed at an attractive stringlike nanowire and construct the complete structural phase diagram in dependence of the binding strength and effective thickness of the nanowire. For this purpose, Monte Carlo optimization techniques are employed to identify lowest-energy structures for a coarse-grained model of a polymer in contact with the nanowire. Among the representative conformations in the different phases are, for example, compact droplets attached to the wire and also nanotubelike monolayer films wrapping it in a very ordered way. We here systematically analyze low-energy shapes and structural order parameters to elucidate the transitions between the structural phases.

  1. Conformational phase diagram for polymers adsorbed on ultrathin nanowires.

    PubMed

    Vogel, Thomas; Bachmann, Michael

    2010-05-14

    We study the conformational behavior of a polymer adsorbed at an attractive stringlike nanowire and construct the complete structural phase diagram in dependence of the binding strength and effective thickness of the nanowire. For this purpose, Monte Carlo optimization techniques are employed to identify lowest-energy structures for a coarse-grained model of a polymer in contact with the nanowire. Among the representative conformations in the different phases are, for example, compact droplets attached to the wire and also nanotubelike monolayer films wrapping it in a very ordered way. We here systematically analyze low-energy shapes and structural order parameters to elucidate the transitions between the structural phases.

  2. Electrically heated particulate filter regeneration using hydrocarbon adsorbents

    DOEpatents

    Gonze, Eugene V [Pinckney, MI; Ament, Frank [Troy, MI

    2011-02-01

    An exhaust system that processes exhaust generated by an engine is provided. The system generally includes a particulate filter (PF) that filters particulates from the exhaust wherein an upstream end of the PF receives exhaust from the engine. A grid of electrically resistive material selectively heats exhaust passing through the upstream end to initiate combustion of particulates within the PF. A hydrocarbon adsorbent coating applied to the PF releases hydrocarbons into the exhaust to increase a temperature of the combustion of the particulates within the PF.

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

    NASA Astrophysics Data System (ADS)

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

    2018-03-01

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

  4. Highly effective removal of mercury and lead ions from wastewater by mercaptoamine-functionalised silica-coated magnetic nano-adsorbents: Behaviours and mechanisms

    NASA Astrophysics Data System (ADS)

    Bao, Shuangyou; Li, Kai; Ning, Ping; Peng, Jinhui; Jin, Xu; Tang, Lihong

    2017-01-01

    A novel hybrid material was fabricated using mercaptoamine-functionalised silica-coated magnetic nanoparticles (MAF-SCMNPs) and was effective in the extraction and recovery of mercury and lead ions from wastewater. The properties of this new magnetic material were explored using various characterisation and analysis methods. Adsorbent amounts, pH levels and initial concentrations were optimised to improve removal efficiency. Additionally, kinetics, thermodynamics and adsorption isotherms were investigated to determine the mechanism by which the fabricated MAF-SCMNPs adsorb heavy metal ions. The results revealed that MAF-SCMNPs were acid-resistant. Sorption likely occurred by chelation through the amine group and ion exchange between heavy metal ions and thiol functional groups on the nanoadsorbent surface. The equilibrium was attained within 120 min, and the adsorption kinetics showed pseudo-second-order (R2 > 0.99). The mercury and lead adsorption isotherms were in agreement with the Freundlich model, displaying maximum adsorption capacities of 355 and 292 mg/g, respectively. The maximum adsorptions took place at pH 5-6 and 6-7 for Hg(II) and Pb(II), respectively. The maximum adsorptions were observed at 10 mg and 12 mg adsorbent quantities for Hg(II) and Pb(II), respectively. The adsorption process was endothermic and spontaneous within the temperature range of 298-318 K. This work demonstrates a unique magnetic nano-adsorbent for the removal of Hg(II) and Pb(II) from wastewater.

  5. Formation of Molecular Networks: Tailored Quantum Boxes and Behavior of Adsorbed CO in Them

    NASA Astrophysics Data System (ADS)

    Wyrick, Jon; Sun, Dezheng; Kim, Dae-Ho; Cheng, Zhihai; Lu, Wenhao; Zhu, Yeming; Luo, Miaomiao; Kim, Yong Su; Rotenberg, Eli; Kim, Kwangmoo; Einstein, T. L.; Bartels, Ludwig

    2011-03-01

    We show that the behavior of CO adsorbed into the pores of large regular networks on Cu(111) is significantly affected by their nano-scale lateral confinement and that formation of the networks themselves is directed by the Shockley surface state. Saturation coverages of CO are found to exhibit persistent dislocation lines; at lower coverages their mobility increases. Individual CO within the pores titrate the surface state, providing crucial information for understanding formation of the network as a result of optimization of the number N of electrons bound within each pore. Determination of N is based on quinone-coverage-dependent UPS data and an analysis of states of particles in a pore-shaped box (verified by CO's titration); a wide range of possible pore shapes and sizes has been considered. Work at UCR supported by NSF CHE 07-49949; at UMD by NSF CHE 07-50334 & UMD NSF-MRSEC DMR 05-20471.

  6. Metallofullerenes as fuel cell electrocatalysts: a theoretical investigation of adsorbates on C59Pt.

    PubMed

    Gabriel, Margaret A; Genovese, Luigi; Krosnicki, Guillaume; Lemaire, Olivier; Deutsch, Thierry; Franco, Alejandro A

    2010-08-28

    Nano-structured electrode degradation in state-of-the-art polymer electrolyte membrane fuel cells (PEMFCs) is one of the main shortcomings that limit the large-scale development and commercialization of this technology. During normal operating conditions of the fuel cell, the PEMFC lifetime tends to be limited by coarsening of the cathode's Pt-based catalyst and by corrosion of the cathode's carbon black support. Because of their chemical properties, metallofullerenes such as C(59)Pt may be more electrochemically stable than the Pt/C mixture. In this paper we investigate, by theoretical methods, the stability of oxygen reduction reaction (ORR) adsorbates on the metallofullerene C(59)Pt and evaluate its potential as a PEMFC fuel cell catalyst.

  7. Investigation of the SERS Spectra of Hydroquinone Molecule Adsorbed on Titanium Dioxide

    NASA Astrophysics Data System (ADS)

    Polubotko, A. M.; Chelibanov, V. P.

    2018-01-01

    The paper analyzes the SERS spectrum of hydroquinone adsorbed on nanoparticles of titanium dioxide (TiO2). It is seen that the enhancement is stronger for a larger mean size of nanoparticles that is in agreement with an electrostatic approximation. In addition, it is found that there are the lines, which are forbidden in usual Raman spectra. There is also an enhancement caused both by the normal and tangential components of the electric field. This result is in agreement with the theory of SERS on semiconductor and dielectric substrates. The discovery of the forbidden lines indicates on the sufficiently large role of the strong quadrupole light-molecule interaction in such a system.

  8. Development of a 3-step straight-through purification strategy combining membrane adsorbers and resins.

    PubMed

    Hughson, Michael D; Cruz, Thayana A; Carvalho, Rimenys J; Castilho, Leda R

    2017-07-01

    The pressures to efficiently produce complex biopharmaceuticals at reduced costs are driving the development of novel techniques, such as in downstream processing with straight-through processing (STP). This method involves directly and sequentially purifying a particular target with minimal holding steps. This work developed and compared six different 3-step STP strategies, combining membrane adsorbers, monoliths, and resins, to purify a large, complex, and labile glycoprotein from Chinese hamster ovary cell culture supernatant. The best performing pathway was cation exchange chromatography to hydrophobic interaction chromatography to affinity chromatography with an overall product recovery of up to 88% across the process and significant clearance of DNA and protein impurities. This work establishes a platform and considerations for the development of STP of biopharmaceutical products and highlights its suitability for integration with single-use technologies and continuous production methods. © 2017 American Institute of Chemical Engineers Biotechnol. Prog., 33:931-940, 2017. © 2017 American Institute of Chemical Engineers.

  9. Deformability of adsorbents during adsorption and principles of the thermodynamics of solid-phase systems

    NASA Astrophysics Data System (ADS)

    Tovbin, Yu. K.

    2017-09-01

    A microscopic theory of adsorption, based on a discrete continuum lattice gas model for noninert (including deformable) adsorbents that change their lattice parameters during adsorption, is presented. Cases of the complete and partial equilibrium states of the adsorbent are considered. In the former, the adsorbent consists of coexisting solid and vapor phases of adsorbent components, and the adsorbate is a mobile component of the vapor phase with an arbitrary density (up to that of the liquid adsorbate phase). The adsorptive transitioning to the bound state changes the state of the near-surface region of the adsorbent. In the latter, there are no equilibrium components of the adsorbent between the solid and vapor phases. The adsorbent state is shown to be determined by its prehistory, rather than set by chemical potentials of vapor of its components. Relations between the microscopic theory and thermodynamic interpretations are discussed: (1) adsorption on an open surface, (2) two-dimensional stratification of the adsorbate mobile phase on an open homogeneous surface, (3) small microcrystals in vacuum and the gas phase, and (4) adsorption in porous systems.

  10. The Influence of Cloud Field Uniformity on Observed Cloud Amount

    NASA Astrophysics Data System (ADS)

    Riley, E.; Kleiss, J.; Kassianov, E.; Long, C. N.; Riihimaki, L.; Berg, L. K.

    2017-12-01

    Two ground-based measurements of cloud amount include cloud fraction (CF) obtained from time series of zenith-pointing radar-lidar observations and fractional sky cover (FSC) acquired from a Total Sky Imager (TSI). In comparison with the radars and lidars, the TSI has a considerably larger field of view (FOV 100° vs. 0.2°) and therefore is expected to have a different sensitivity to inhomogeneity in a cloud field. Radiative transfer calculations based on cloud properties retrieved from narrow-FOV overhead cloud observations may differ from shortwave and longwave flux observations due to spatial variability in local cloud cover. This bias will impede radiative closure for sampling reasons rather than the accuracy of cloud microphysics retrievals or radiative transfer calculations. Furthermore, the comparison between observed and modeled cloud amount from large eddy simulations (LES) models may be affected by cloud field inhomogeneity. The main goal of our study is to estimate the anticipated impact of cloud field inhomogeneity on the level of agreement between CF and FSC. We focus on shallow cumulus clouds observed at the U.S. Department of Energy Atmospheric Radiation Measurement Facility's Southern Great Plains (SGP) site in Oklahoma, USA. Our analysis identifies cloud field inhomogeneity using a novel metric that quantifies the spatial and temporal uniformity of FSC over 100-degree FOV TSI images. We demonstrate that (1) large differences between CF and FSC are partly attributable to increases in inhomogeneity and (2) using the uniformity metric can provide a meaningful assessment of uncertainties in observed cloud amount to aide in comparing ground-based measurements to radiative transfer or LES model outputs at SGP.

  11. SO x /NO x Removal from Flue Gas Streams by Solid Adsorbents: A Review of Current Challenges and Future Directions

    SciTech Connect

    Rezaei, Fateme; Rownaghi, Ali A.; Monjezi, Saman

    One of the main challenges in the power and chemical industries is to remove generated toxic or environmentally harmful gases before atmospheric emission. To comply with stringent environmental and pollutant emissions control regulations, coal-fired power plants must be equipped with new technologies that are efficient and less energy-intensive than status quo technologies for flue gas cleanup. While conventional sulfur oxide (SOx) and nitrogen oxide (NOx) removal technologies benefit from their large-scale implementation and maturity, they are quite energy-intensive. In view of this, the development of lower-cost, less energy-intensive technologies could offer an advantage. Significant energy and cost savings can potentiallymore » be realized by using advanced adsorbent materials. One of the major barriers to the development of such technologies remains the development of materials that are efficient and productive in removing flue gas contaminants. In this review, adsorption-based removal of SOx/NOx impurities from flue gas is discussed, with a focus on important attributes of the solid adsorbent materials as well as implementation of the materials in conventional and emerging acid gas removal technologies. The requirements for effective adsorbents are noted with respect to their performance, key limitations, and suggested future research directions. The final section includes some key areas for future research and provides a possible roadmap for the development of technologies for the removal of flue gas impurities that are more efficient and cost-effective than status quo approaches.« less

  12. The effect of sputter temperature on vacancy island behavior on Ni(111) measured by photoemission of adsorbed xenon

    NASA Astrophysics Data System (ADS)

    Malafsky, Geoffrey P.

    1994-04-01

    The temperature dependence of vacancy coalescence on an ion bombarded Ni(111) surface is measured by photoemission of adsorbed xenon (PAX). The Ni(111) crystal is sputtered by a low fluence (0.06 ML incident ions) Ar + ion beam with incident kinetic energies of 500-3000 eV. The Xe coverage decreases rapidly with increasing temperature between 88 and 375 K with little additional change from 375 to 775 K. The PAX spectra are acquired with a Xe chamber pressure of 8 × 10 -10 Torr and at a temperature of 88 K. Under these conditions, the Xe is selectively adsorbed at defect sites which would make the Xe coverage proportional to the surface defect density on simple defect structures but the large size of the Xe atom relative to the Ni atom prevents the direct relationship of Xe coverage to the defect density when complex and varying defect structures are present. The decrease in Xe coverage is not attributed to the loss of defect sites by adatom-vacancy recombination but the changing vacancy island shape and size with temperature which alters the ratio of adsorbed Xe atoms to surface vacancy sites. This ratio decreases with increasing temperature as the vacancy islands progress from small and irregularly shaped islands to larger and hexagonally shaped islands. This transition is seen in Monte Carlo simulations of the kinetically driven atomic diffusion on the sputtered surface.

  13. Physical adsorption at the nanoscale: Towards controllable scaling of the substrate-adsorbate van der Waals interaction

    NASA Astrophysics Data System (ADS)

    Ambrosetti, Alberto; Silvestrelli, Pier Luigi; Tkatchenko, Alexandre

    2017-06-01

    The Lifshitz-Zaremba-Kohn (LZK) theory is commonly considered as the correct large-distance limit for the van der Waals (vdW) interaction of adsorbates (atoms, molecules, or nanoparticles) with solid substrates. In the standard approximate form, implicitly based on local dielectric functions, the LZK approach predicts universal power laws for vdW interactions depending only on the dimensionality of the interacting objects. However, recent experimental findings are challenging the universality of this theoretical approach at finite distances of relevance for nanoscale assembly. Here, we present a combined analytical and numerical many-body study demonstrating that physical adsorption can be significantly enhanced at the nanoscale. Regardless of the band gap or the nature of the adsorbate specie, we find deviations from conventional LZK power laws that extend to separation distances of up to 10-20 nm. Comparison with recent experimental observations of ultra-long-ranged vdW interactions in the delamination of graphene from a silicon substrate reveals qualitative agreement with the present theory. The sensitivity of vdW interactions to the substrate response and to the adsorbate characteristic excitation frequency also suggests that adsorption strength can be effectively tuned in experiments, paving the way to an improved control of physical adsorption at the nanoscale.

  14. Selective adsorption for removal of nitrogen compounds from hydrocarbon streams over carbon-based adsorbents

    NASA Astrophysics Data System (ADS)

    Almarri, Masoud S.

    desulfurization of model diesel fuel, which contains equimolar concentrations of nitrogen (i.e., quinoline and indole), sulfur (i.e., dibenzothiophene and 4,6-dimethyldibenzothiophene), and aromatic compounds (naphthalene, 1-methylnaphthalene, and fluorene), was examined. The results revealed that when both nitrogen and sulfur compounds coexist in the fuel, the type and density of oxygen functional groups on the surface of the activated carbon are crucial for selective adsorption of nitrogen compounds but have negligible positive effects for sulfur removal. The adsorption of quinoline and indole is largely governed by specific interactions. There is enough evidence to support the importance of dipole--dipole and acid-base-specific interactions for the adsorption of both quinoline and indole. Modified carbon is a promising material for the efficient removal of the nitrogen compounds from light cycle oil (LCO). Adsorptive denitrogenation of LCO significantly improved the hydrodesulfurization (HDS) performance, especially for the removal of the refractory sulfur compounds such as 4-methyldibenzothiophene and 4,6-dimethyldibenzothiophene. An essential factor in applying activated carbon for adsorptive denitrogenation and desulfurization of liquid hydrocarbon streams is regeneration after saturation. The regeneration method of the saturated adsorbents consisted of toluene washing followed by heating to remove the remaining toluene. The results show that the spent activated carbon can be regenerated to completely recover the adsorption capacity. The high capacity and selectivity of activated carbon for nitrogen compounds, along with their ability to be regenerated, indicate that activated carbon is a promising adsorbent for the deep denitrogenation of liquid hydrocarbon streams.

  15. Sustainable conversion of agro-wastes into useful adsorbents

    NASA Astrophysics Data System (ADS)

    Bello, Olugbenga Solomon; Owojuyigbe, Emmanuel Seun; Babatunde, Monsurat Abiodun; Folaranmi, Folasayo Eunice

    2017-11-01

    Preparation and characterization of raw and activated carbon derived from three different selected agricultural wastes: kola nut pod raw and activated (KNPR and KNPA), bean husk raw and activated (BHR and BHA) and coconut husk raw and activated (CHR and CHA) were investigated, respectively. Influences of carbonization and acid activation on the activated carbon were investigated using SEM, FTIR, EDX, pHpzc and Boehm titration techniques, respectively. Carbonization was done at 350 °C for 2 h followed by activation with 0.3 M H3PO4 (ortho-phosphoric acid). Results obtained from SEM, FTIR, and EDX revealed that, carbonization followed by acid activation had a significant influence on morphology and elemental composition of the samples. SEM showed well-developed pores on the surface of the precursors after acid treatment, FTIR spectra revealed reduction, broadening, disappearance or appearance of new peaks after acid activation. EDX results showed highest percentage of carbon by atom respectively in the order BHA > KNPA > CHA respectively. The pHpzc was found to be 5.32, 4.57 and 3.69 for KNPA, BHA and CHA, respectively. Boehm titration result compliments that of pHpzc, indicating that the surfaces of the prepared adsorbents are predominantly acidic. This study promotes a sustainable innovative use of agro-wastes in the production of cheap and readily available activated carbons, thereby ensuring more affordable water and effluent treatment adsorbents.

  16. Pulling adsorbed polymers at an angle: A low temperature theory

    NASA Astrophysics Data System (ADS)

    Iliev, Gerasim; Whittington, Stuart

    2012-02-01

    We consider several partially-directed walk models in two- and three-dimensions to study the problem of a homopolymer interacting with a surface while subject to a force at the terminal monomer. The force is applied with a component parallel to the surface as well as a component perpendicular to the surface. Depending on the relative values of the force in each direction, the force can either enhance the adsorption transition or lead to desorption in an adsorbed polymer. For each model, we determine the associated generating function and extract the phase diagram, identifying states where the polymer is thermally desorbed, adsorbed, and under the influence of the force. We note the different regimes that appear in the problem and provide a low temperature approximation to describe them. The approximation is exact at T=0 and models the exact results extremely well for small values of T. This work is an extension of a model considered by S. Whittington and E. Orlandini.

  17. Forces between Two Glass Surfaces with Adsorbed Hexadecyltrimethylammonium Salicylate.

    PubMed

    Imae, T; Kato, M; Rutland, M

    2000-02-22

    Forces have been measured for hexadecyltrimethylammonium salicylate (C(16)TASal) layers on glass beads. During the inward process, hydrophobic attraction occurred at lower adsorption of C(16)TASal and electrostatic repulsion interactions happened at higher adsorption. While the jump-in phenomenon was observed for solutions of concentrations below the critical micelle concentration (cmc = 0.15 mM), the step-in phenomenon was characteristic for solutions at the cmc and above the cmc, suggesting the push-out of adsorbed C(16)TASal layers and/or inserted micelles. The remarkable pull-off phenomenon on the outward process occurred for all solutions, indicating a strong interaction between C(16)TASal molecules. For aqueous 0.15 mM C(16)TASal solutions of various NaSal concentrations, on the inward process, the electrostatic repulsive interaction decreased with adding NaSal. This is due to the electrostatic shielding by salt excess. The height of the force wall on the inward process reached a maximum at 0.01 M NaSal, but the interlocking between molecules on two surfaces during the outward process was minimized at 0.1 M NaSal. These tendencies, which are different from that of the electrostatic repulsion interaction, imply the strong cohesion between adsorbed C(16)TASal layers.

  18. Electronic damping of anharmonic adsorbate vibrations at metallic surfaces

    NASA Astrophysics Data System (ADS)

    Tremblay, Jean Christophe; Monturet, Serge; Saalfrank, Peter

    2010-03-01

    The nonadiabatic coupling of an adsorbate close to a metallic surface leads to electronic damping of adsorbate vibrations and line broadening in vibrational spectroscopy. Here, a perturbative treatment of the electronic contribution to the lifetime broadening serves as a building block for a new approach, in which anharmonic vibrational transition rates are calculated from a position-dependent coupling function. Different models for the coupling function will be tested, all related to embedding theory. The first two are models based on a scattering approach with (i) a jellium-type and (ii) a density functional theory based embedding density, respectively. In a third variant a further refined model is used for the embedding density, and a semiempirical approach is taken in which a scaling factor is chosen to match harmonic, single-site, first-principles transition rates, obtained from periodic density functional theory. For the example of hydrogen atoms on (adsorption) and below (subsurface absorption) a Pd(111) surface, lifetimes of and transition rates between vibrational levels are computed. The transition rates emerging from different models serve as input for the selective subsurface adsorption of hydrogen in palladium starting from an adsorption site, by using sequences of infrared laser pulses in a laser distillation scheme.

  19. Radiolytic stability of gibbsite and boehmite with adsorbed water

    NASA Astrophysics Data System (ADS)

    Huestis, Patricia; Pearce, Carolyn I.; Zhang, X.; N'Diaye, Alpha T.; Rosso, Kevin M.; LaVerne, Jay A.

    2018-04-01

    Aluminum oxyhydroxide (boehmite, AlOOH) and aluminum hydroxide (gibbsite, Al(OH)3) powders with adsorbed water were irradiated with γ-rays and 5 MeV He ions (α-particles) in order to determine overall radiation stability and chemical modification to the surface. No variation in overall phase or crystallinity due to radiolysis was observed with X-ray diffraction (XRD) and Raman spectroscopy for doses up to 2 MGy with γ-rays and 175 MGy with α-particles. Temperature programed desorption (TPD) of the water from the surface to the gas phase indicated that the water was chemisorbed and strongly bound. Water adsorption sites are of similar energy for both gibbsite and boehmite. Observation of the water adsorbed on the surface of gibbsite and boehmite with diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS) showed broad peaks at 3100-3600 cm-1 due to OH stretching that slowly decreased on heating to 500 °C, which corresponds well with the water vapor evolution observed with TPD. Both materials were found to be amorphous following heating to 500 °C. X-ray photoelectron spectroscopy (XPS) indicated surface reduction of Al(III) to Al metal on radiolysis with α-particles. Complete loss of chemisorbed water and the formation of bulk O atoms was observed following radiolysis with α-particles.

  20. Radiolytic stability of gibbsite and boehmite with adsorbed water

    SciTech Connect

    Huestis, Patricia; Pearce, Carolyn I.; Zhang, X.

    Aluminum oxyhydroxide (boehmite, AlOOH) and aluminum hydroxide (gibbsite, Al(OH)3) powders with adsorbed water were irradiated with -rays and 5 MeV He ions (α-particles) in order to determine overall radiation stability and chemical modification to the surface. No variation in overall phase or crystallinity due to radiolysis was observed with X-ray diffraction (XRD) and Raman spectroscopy for doses up to 2 MGy with -rays and 175 MGy with α-particles. Temperature programed desorption (TPD) of the water from the surface to the gas phase indicated that the water was chemisorbed and strongly bound. Water adsorption sites are of similar energy for bothmore » gibbsite and boehmite. Observation of the water adsorbed on the surface of gibbsite and boehmite with diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS) showed broad peaks at 3100-3600 cm-1 due to OH stretching that slowly decreased on heating to 500oC, which corresponds well with the water vapor evolution observed with TPD. Both materials were found to be amorphous following heating to 500oC. X-ray photoelectron spectroscopy (XPS) indicated surface reduction of Al(III) to Al metal on radiolysis with α-particles. Complete loss of chemisorbed water and the formation of bulk O atoms was observed following radiolysis with α-particles.« less

  1. Adsorbed Polymer Nanolayers on Solids: Mechanism, Structure and Applications

    NASA Astrophysics Data System (ADS)

    Sen, Mani Kuntal

    In this thesis, by combining various advanced x-ray scattering, spectroscopic and other surface sensitive characterization techniques, I report the equilibrium polymer chain conformations, structures, dynamics and properties of polymeric materials at the solid-polymer melt interfaces. Following the introduction, in chapter 2, I highlight that the backbone chains (constituted of CH and CH2 groups) of the flattened polystyrene (PS) chains preferentially orient normal to the weakly interactive substrate surface via thermal annealing regardless of the initial chain conformations, while the orientation of the phenyl rings becomes randomized, thereby increasing the number of surface-segmental contacts (i.e., enthalpic gain) which is the driving force for the flattening process of the polymer chains even onto a weakly interactive solid. In chapter 3, I elucidate the flattened structures in block copolymer (BCP) thin films where both blocks lie flat on the substrate, forming a 2D randomly phase-separated structure irrespective of their microdomain structures and interfacial energetics. In chapter 4, I reveal the presence of an irreversibly adsorbed BCP layer which showed suppressed dynamics even at temperatures far above the individual glass transition temperatures of the blocks. Furthermore, this adsorbed BCP layer plays a crucial role in controlling the microdomain orientation in the entire film. In chapter 5, I report a radically new paradigm of designing a polymeric coating layer of a few nanometers thick ("polymer nanolayer") with anti-biofouling properties.

  2. Chemical and structural characterization of copper adsorbed on mosses (Bryophyta).

    PubMed

    González, Aridane G; Jimenez-Villacorta, Felix; Beike, Anna K; Reski, Ralf; Adamo, Paola; Pokrovsky, Oleg S

    2016-05-05

    The adsorption of copper on passive biomonitors (devitalized mosses Hypnum sp., Sphagnum denticulatum, Pseudoscleropodium purum and Brachythecium rutabulum) was studied under different experimental conditions such as a function of pH and Cu concentration in solution. Cu assimilation by living Physcomitrella patents was also investigated. Molecular structure of surface adsorbed and incorporated Cu was studied by X-ray Absorption Spectroscopy (XAS). Devitalized mosses exhibited the universal adsorption pattern of Cu as a function of pH, with a total binding sites number 0.05-0.06 mmolg(dry)(-1) and a maximal adsorption capacity of 0.93-1.25 mmolg(dry)(-1) for these devitalized species. The Extended X-ray Absorption Fine Structure (EXAFS) fit of the first neighbor demonstrated that for all studied mosses there are ∼4.5 O/N atoms around Cu at ∼1.95 Å likely in a pseudo-square geometry. The X-ray Absorption Near Edge Structure (XANES) analysis demonstrated that Cu(II)-cellulose (representing carboxylate groups) and Cu(II)-phosphate are the main moss surface binding moieties, and the percentage of these sites varies as a function of solution pH. P. patens exposed during one month to Cu(2+) yielded ∼20% of Cu(I) in the form of Cu-S(CN) complexes, suggesting metabolically-controlled reduction of adsorbed and assimilated Cu(2+). Copyright © 2016 Elsevier B.V. All rights reserved.

  3. Prepared multifunctional aerogel for high performance supercapacitors and effective adsorbents

    NASA Astrophysics Data System (ADS)

    Zhang, Yimei; Wang, Fei; Ou, Ping; Zhu, Hao; Zhao, Yalong; Wang, Liquan; Chen, Zhuang; Li, Shuai

    2018-05-01

    Energy and environment as the current research hots pot, how to effectively combine the two is very important and full of challenge. In this research, we design a new type multifunctional aerogel material, which not only can applied for supuercapacitors, but also acted as adsorbents for adsorb organic pollutant. This multifunctional aerogel was prepared by one-pot hydrothermal and freeze-drying method based on elongated TiO2 nanotubes (eTNTs) and graphene. During the hydrothermal process, the graphene nanosheets and eTNTs self-assembled into three-dimensional (3D) interconnected networks, in which the eTNTs with uniform size are intercalate the pore interconnected framework. The results show that the as-prepared eTNTs/graphene aerogel (TGA) exhibits a high specific surface area of 343.2 m2 g‑1. The highly porous and interconnected 3D nanostructure provided efficient migration of electrolyte ions and electrons, and thus the TGA exhibited excellent electrochemical performance for supercapacitors. The binder free TGA electrode possessed high performance electrochemical properties with an excellent specific capacitance (476.8 F g‑1 at scan rate of 5 mV s‑1), and outstanding cycle stability (92% capacitance retention after 5000 cycles). In addition, the TGA also showed admirable adsorption capacity for organic pollutant of bisphenol A, which reached 523.5 mg g‑1. The excellent electrochemical and adsorption capacities suggest the TGA to be the promising materials application in energy storage and environmental remediation.

  4. 9 CFR 381.412 - Reference amounts customarily consumed per eating occasion.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... appropriate national food consumption surveys. (2) The Reference Amounts are calculated for an infant or child... are based on data set forth in appropriate national food consumption surveys. Such Reference Amounts... child under 4 years of age. (3) An appropriate national food consumption survey includes a large sample...

  5. 9 CFR 381.412 - Reference amounts customarily consumed per eating occasion.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... appropriate national food consumption surveys. (2) The Reference Amounts are calculated for an infant or child... are based on data set forth in appropriate national food consumption surveys. Such Reference Amounts... child under 4 years of age. (3) An appropriate national food consumption survey includes a large sample...

  6. 9 CFR 317.312 - Reference amounts customarily consumed per eating occasion.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... appropriate national food consumption surveys. (2) The Reference Amounts are calculated for an infant or child... are based on data set forth in appropriate national food consumption surveys. Such Reference Amounts... child under 4 years of age. (3) An appropriate national food consumption survey includes a large sample...

  7. 9 CFR 317.312 - Reference amounts customarily consumed per eating occasion.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... appropriate national food consumption surveys. (2) The Reference Amounts are calculated for an infant or child... are based on data set forth in appropriate national food consumption surveys. Such Reference Amounts... child under 4 years of age. (3) An appropriate national food consumption survey includes a large sample...

  8. 9 CFR 381.412 - Reference amounts customarily consumed per eating occasion.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... appropriate national food consumption surveys. (2) The Reference Amounts are calculated for an infant or child... are based on data set forth in appropriate national food consumption surveys. Such Reference Amounts... child under 4 years of age. (3) An appropriate national food consumption survey includes a large sample...

  9. 9 CFR 317.312 - Reference amounts customarily consumed per eating occasion.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... appropriate national food consumption surveys. (2) The Reference Amounts are calculated for an infant or child... are based on data set forth in appropriate national food consumption surveys. Such Reference Amounts... child under 4 years of age. (3) An appropriate national food consumption survey includes a large sample...

  10. What Determines the Amount Students Borrow? Revisiting the Crisis-Convenience Debate

    ERIC Educational Resources Information Center

    Hart, Natala K.; Mustafa, Shoumi

    2008-01-01

    Recent studies have questioned the wisdom in blaming college costs for the escalation of student loans. It would appear that less affluent students borrow large amounts because inexpensive subsidized loans are available. This study attempted to verify the claim, estimating a model of the amount of loan received by students as a function of net…

  11. 48 CFR 970.5215-1 - Total available fee: Base fee amount and performance fee amount.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... unilateral determination made by the DOE Operations/Field Office Manager, or designee. (3) The evaluation of.../Field Office Manager, or designee, will be (insert title of DOE Operations/Field Office Manager, or... available fee amount earned determinations. The DOE Operations/Field Office Manager, or designee, shall...

  12. 48 CFR 970.5215-1 - Total available fee: Base fee amount and performance fee amount.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... unilateral determination made by the DOE Operations/Field Office Manager, or designee. (3) The evaluation of.../Field Office Manager, or designee, will be (insert title of DOE Operations/Field Office Manager, or... available fee amount earned determinations. The DOE Operations/Field Office Manager, or designee, shall...

  13. 48 CFR 970.5215-1 - Total available fee: Base fee amount and performance fee amount.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... unilateral determination made by the DOE Operations/Field Office Manager, or designee. (3) The evaluation of.../Field Office Manager, or designee, will be (insert title of DOE Operations/Field Office Manager, or... available fee amount earned determinations. The DOE Operations/Field Office Manager, or designee, shall...

  14. 48 CFR 970.5215-1 - Total available fee: Base fee amount and performance fee amount.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... unilateral determination made by the DOE Operations/Field Office Manager, or designee. (3) The evaluation of.../Field Office Manager, or designee, will be (insert title of DOE Operations/Field Office Manager, or... available fee amount earned determinations. The DOE Operations/Field Office Manager, or designee, shall...

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

    PubMed

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

    2011-07-01

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

  16. Preparation and characterization of novel carbon dioxide adsorbents based on polyethylenimine-modified Halloysite nanotubes.

    PubMed

    Cai, Haohao; Bao, Feng; Gao, Jie; Chen, Tao; Wang, Si; Ma, Rui

    2015-01-01

    New nano-sized carbon dioxide (CO2) adsorbents based on Halloysite nanotubes impregnated with polyethylenimine (PEI) were designed and synthesized, which were excellent adsorbents for the capture of CO2 at room temperature and had relatively high CO2 adsorption capacity. The prepared adsorbents were characterized by various techniques such as Fourier transform infrared spectrometry, gel permeation chromatography, dynamic light scattering, thermogravimetry, thermogravimetry-Fourier transform-infrared spectrometry, scanning electron microscopy and transmission electron microscopy. The adsorption characteristics and capacity were studied at room temperature, the highest CO2 adsorption capacity of 156.6 mg/g-PEI was obtained and the optimal adsorption capacity can reach a maximum value of 54.8 mg/g-adsorbent. The experiment indicated that this kind of adsorbent has a high stability at 80°C and PEI-impregnated adsorbents showed good reversibility and stability during cyclic adsorption-regeneration tests.

  17. 27 CFR 40.133 - Amount of individual bond.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... amount, the manufacturer shall immediately file a strengthening or superseding bond as required by this subpart. The amount of any such bond (or the total amount including strengthening bonds, if any) need not...

  18. 27 CFR 40.133 - Amount of individual bond.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... amount, the manufacturer shall immediately file a strengthening or superseding bond as required by this subpart. The amount of any such bond (or the total amount including strengthening bonds, if any) need not...

  19. Querying Large Biological Network Datasets

    ERIC Educational Resources Information Center

    Gulsoy, Gunhan

    2013-01-01

    New experimental methods has resulted in increasing amount of genetic interaction data to be generated every day. Biological networks are used to store genetic interaction data gathered. Increasing amount of data available requires fast large scale analysis methods. Therefore, we address the problem of querying large biological network datasets.…

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

    PubMed

    Habibi, Nasim; Rouhi, Parham; Ramavandi, Bahman

    2017-08-01

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

  1. Just the Right Amount of Reinforcement

    NASA Technical Reports Server (NTRS)

    Walton, Greg

    1998-01-01

    Lockheed Martin Skunk Works, is taking the next step towards economical low-Earth-orbit (LEO) operations with NASA's X-33 technology demonstrator, that uses composite tanks for liquid hydrogen (LH sub2) fuel storage and structural support, The X-33 is a 53% scale model of the VentureStar single-stage-to-orbit (SSTO) reusable launch vehicle(RLV) projected to orbit payloads at a rate, of $1,000 per pound beginning in 2004 In order to make VentureStar completely reusable and economical engineers are using composite materials throughout the spacecrafts structure. The first test of the design comes in 1999 on the X-33 technology demonstrator. Two of the primary structures that engineers will be evaluating are the carbon fiber/epoxy LH2 fuel tanks. The 29-ft long by 18-ft wide tanks, which fill two-thirds of the X-33's interior, serve a dual purpose carrying fuel and providing structural support to the walls of the spacecraft. Fiber placement makes it possible to build the fuel tanks, large, light and strong enough to satisfy X33's requirements. Lockheed Martin choose the fabrication technology to produce the eight sections of each tank because of fiber placement's ability to handle complex surfaces, speed and repeatability.

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

    SciTech Connect

    Gill, Gary A.; Kuo, Li-Jung; Strivens, Jonathan E.

    2015-06-01

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

  3. Biodegradable metal adsorbent synthesized by graft polymerization onto nonwoven cotton fabric

    NASA Astrophysics Data System (ADS)

    Sekine, Ayako; Seko, Noriaki; Tamada, Masao; Suzuki, Yoshio

    2010-01-01

    A fibrous adsorbent for Hg ions was synthesized by radiation-induced emulsion graft polymerization of glycidyl methacrylate (GMA) onto a nonwoven cotton fabric and subsequent chemical modification. The optimal pre-irradiation dose for initiation of the graft polymerization of GMA, which minimized the effects of radiation damage on the mechanical strength of the nonwoven cotton fabric, was found to be 10 kGy. The GMA-grafted nonwoven cotton fabric was subsequently modified with ethylenediamine (EDA) or diethylenetriamine (DETA) to obtain a Hg adsorbent. The resulting amine-type adsorbents were evaluated for batch and continuous adsorption of Hg. In batch adsorption, the distribution coefficients of Hg reached 1.9×10 5 and 1.0×10 5 for EDA- and DETA-type adsorbents, respectively. A column packed with EDA-type adsorbent removed Hg from 1.8 ppm Hg solution at a space velocity of 100 h -1, which corresponds to 16,000 times the volume of the packed adsorbent. The adsorbed Hg on the EDA-type adsorbent could be completely eluted by 1 M HCl solution. A microbial oxidative degradation test revealed that the EDA-type adsorbent is biodegradable.

  4. Effect of Solid to Liquid Ratio on Heavy Metal Removal by Geopolymer-Based Adsorbent

    NASA Astrophysics Data System (ADS)

    Ariffin, N.; Abdullah, M. M. A. B.; Arif Zainol, M. R. R. Mohd; Baltatu, M. S.; Jamaludin, L.

    2018-06-01

    Microstructure of three-dimensional aluminosilicate which similar to zeolite cause geopolymer based adsorbent accepted in the treatment of wastewater. This paper presents an investigation on the copper removal from the wastewater by varying the solid to liquid ratio in the fly ash, kaolin and sludge-based geopolymer adsorbent. The adsorption test was conducted to study the efficiency of the adsorbent and the copper concentration was examined by using Atomic Adsorption Spectrometry (AAS). The optimum solid to liquid ratio with the highest percentage removal were 1.0, 0.5 and 0.8 for fly ash-based geopolymer, kaolin-based geopolymer and sludge-based geopolymer adsorbent.

  5. Preparation of amino acid-based polymer functionalized magnetic nanoparticles as adsorbents for analysis of plant growth regulators in bean sprouts.

    PubMed

    Ji, Shilei; Qi, Li; Li, Nan; Wang, Minglin

    2016-09-01

    A novel magnetic solid phase extraction (MSPE) adsorbent has been developed for enriching two plant growth regulators, including 2,4-dichlorophenoxyacetic acid (2,4-D) and 4-chlorophenoxyacetic acid (4-CPA), in bean sprouts. For preparing the MSPE adsorbent, poly(N-methacryloyl-L-phenylalanine methyl ester (P(MA-L-Phe-OMe)), amino acid-based polymer, was modified onto the magnetic nanoparticles via "grafting to" method by free radical polymerization. The resultant P(MA-L-Phe-OMe)-functionalized magnetic nanoparticles (Fe3O4@P(MA-L-Phe-OMe)) were characterized by Fourier transform infrared (FT-IR) spectroscopy and elemental analysis. The adsorption amount of Fe3O4@P(MA-L-Phe-OMe) nanoparticles to 2,4-D and 4-CPA were 39.82mgg(-1) and 29.02mgg(-1), respectively. Moreover, the prepared MSPE adsorbents showed good selectivity towards 2,4-D and 4-CPA due to the hydrophobic interactions and electrostatic forces between the target analytes and Fe3O4@P(MA-L-Phe-OMe). The results demonstrated that the proposed MSPE adsorbents have high affinity to the targets 2,4-D and 4-CPA. Under the optimized conditions, the proposed materials were successfully applied to enrich 2,4-D and 4-CPA in bean sprouts samples. The recovery values of the bean sprouts solution spiked the targets were from 90.9% to 96.4% with the relative standard deviations of 2.3-3.9%. Our work proved that the novel Fe3O4@P(MA-L-Phe-OMe) nanoparticles were the good adsorbents of magnetic solid phase extraction (MSPE) and have good potential for the analysis of trace compound in real samples. Copyright © 2016 Elsevier B.V. All rights reserved.

  6. The determination of optimum condition in water hyacinth drying process by mixed adsorption drying method and modified fly ash as an adsorbent

    NASA Astrophysics Data System (ADS)

    Saputra, Asep Handaya; Putri, Rizky Anggreini

    2017-05-01

    Water hyacinth is an aquatic weed that has a very fast growth which makes it becomes a problem to the ecosystem. On the other hand, water hyacinth has a high fiber content (up to 20% by weight) which makes it potential to become raw material for composites and textile industries. As an aquatic plant, water hyacinth has a high initial moisture content that reaches more than 90%. Meanwhile the moisture content of fiber as a raw material for composite and textile industry should not be more than 10% to maintain the good quality of the products. Mixed adsorption drying method is one of the innovative method that can replace conventional drying process. Fluidization method which has been commonly used in agricultural and pharmaceutical products drying, can be enhanced by combining it with the adsorption method as performed in this study. In mixed fluidization-adsorption drying method, fly ash as adsorbent and water hyacinth fiber were put together into the fluidization column where the drying air evaporate the moisture content in water hyacinth fiber. In addition, the adsorbent adsorb the moisture content in the drying air to make the moisture content of the drying air remain low. The drying process is performed in various temperature and composition of water hyacinth and adsorbent in order to obtain the optimum drying condition. In addition, the effect of fly ash pellet and fly ash powder to the drying process was also performed. The result shows that the higher temperature and the more amount of adsorbent results in the faster drying rate. Fly ash pellet shows a better adsorption since it has a smaller pore diameter and wider surface area. The optimum temperature obtained from this study is 60°C and the optimum ratio of water hyacinth and fly ash is 50:50.

  7. Comparison of cadmium hydroxide nanowires and silver nanoparticles loaded on activated carbon as new adsorbents for efficient removal of Sunset yellow: Kinetics and equilibrium study.

    PubMed

    Ghaedi, Mehrorang

    2012-08-01

    Adsorption of Sunset yellow (SY) onto cadmium hydroxide nanowires loaded on activated carbon (Cd(OH)(2)-NW-AC) and silver nanoparticles loaded on activated carbon (Ag-NP-AC) was investigated. The effects of pH, contact time, amount of adsorbents, initial dye concentration, agitation speed and temperature on Sunset yellow removal on both adsorbents were studied. Following the optimization of variables, the experimental data were fitted to different conventional isotherm models like Langmuir, Freundlich, Tempkin and Dubinin-Radushkevich (D-R) based on linear regression coefficient R(2) the Langmuir isotherm was found to be the best fitting isotherm model and the maximum monolayer adsorption capacities calculated based on this model for Cd(OH)(2)-NW-AC and Ag-NP-AC were found to be 76.9 and 37.03mg g(-1) at room temperatures, respectively. The experimental fitting of time dependency of adsorption of SY onto both adsorbent shows the applicability of second order kinetic model for interpretation of kinetic data. The pseudo-second order model best fits the adsorption kinetics. Thermodynamic parameters such as enthalpy, entropy, activation energy, sticking probability, and Gibb's free energy changes were also calculated. It was found that the sorption of SY over (Cd(OH)(2)-NW-AC) and (Ag-NP-AC) was spontaneous and endothermic in nature. Efficiency of the adsorbent was also investigated using real effluents and more than 95% SY removal for both adsorbents was observed. Copyright © 2012 Elsevier B.V. All rights reserved.

  8. Optimum Tolerance Design Using Component-Amount and Mixture-Amount Experiments

    SciTech Connect

    Piepel, Gregory F.; Ozler, Cenk; Sehirlioglu, Ali Kemal

    2013-08-01

    One type of tolerance design problem involves optimizing component and assembly tolerances to minimize the total cost (sum of manufacturing cost and quality loss). Previous literature recommended using traditional response surface (RS) designs and models to solve this type of tolerance design problem. In this article, component-amount (CA) and mixture-amount (MA) approaches are proposed as more appropriate for solving this type of tolerance design problem. The advantages of the CA and MA approaches over the RS approach are discussed. Reasons for choosing between the CA and MA approaches are also discussed. The CA and MA approaches (experimental design, response modeling,more » and optimization) are illustrated using real examples.« less

  9. Effective Hubbard model for Helium atoms adsorbed on a graphite

    NASA Astrophysics Data System (ADS)

    Motoyama, Yuichi; Masaki-Kato, Akiko; Kawashima, Naoki

    Helium atoms adsorbed on a graphite is a two-dimensional strongly correlated quantum system and it has been an attractive subject of research for a long time. A helium atom feels Lennard-Jones like potential (Aziz potential) from another one and corrugated potential from the graphite. Therefore, this system may be described by a hardcore Bose Hubbard model with the nearest neighbor repulsion on the triangular lattice, which is the dual lattice of the honeycomb lattice formed by carbons. A Hubbard model is easier to simulate than the original problem in continuous space, but we need to know the model parameters of the effective model, hopping constant t and interaction V. In this presentation, we will present an estimation of the model parameters from ab initio quantum Monte Carlo calculation in continuous space in addition to results of quantum Monte Carlo simulation for an obtained discrete model.

  10. Porous silicon powder as an adsorbent of heavy metal (nickel)

    NASA Astrophysics Data System (ADS)

    Nabil, Marwa; Motaweh, Hussien A.

    2018-04-01

    New and inexpensive nanoporous silicon (NPS) powder was prepared by alkali chemical etching using sonication technique and was subsequently investigated as an adsorbent in batch systems for the adsorption Ni(II) ions in an aqueous solution. The optimum conditions for the Ni(II) ion adsorption capacity of the NPS powder were studied in detail by varying parameters such as the initial Ni(II) concentration, the solution pH value, the adsorption temperature and contact time. The results indicated that the maximum adsorption capacity and the maximum removal percent of Ni(II) reached 2665.33 mg/g and 82.6%, respectively, at an initial Ni(II) concentration of 100 mg/L, adsorption time of 30 min and no effect of the solution pH and adsorption temperature.

  11. Charge transfer properties of pentacene adsorbed on silver: DFT study

    NASA Astrophysics Data System (ADS)

    N, Rekha T.; Rajkumar, Beulah J. M.

    2015-06-01

    Charge transfer properties of pentacene adsorbed on silver is investigated using DFT methods. Optimized geometry of pentacene after adsorption on silver indicates distortion in hexagonal structure of the ring close to the silver cluster and deviations in co-planarity of carbon atoms due to the variations in bond angles and dihedral angles. Theoretically simulated absorption spectrum has a symmetric surface plasmon resonance peak around 486nm corresponding to the transfer of charge from HOMO-2 to LUMO. Theoretical SERS confirms the process of adsorption, tilted orientation of pentacene on silver surface and the charge transfers reported. Localization of electron density arising from redistribution of electrostatic potential together with a reduced bandgap of pentacene after adsorption on silver suggests its utility in the design of electro active organic semiconducting devices.

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

    DOE PAGES

    Hoffmann, F. M.; Hrbek, J.; Ma, S.; ...

    2015-12-02

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

  13. 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. Copyright © 2015 Elsevier B.V. All rights reserved.

  14. Mustard plant ash: a source of micronutrient and an adsorbent for removal of 2,4-dichlorophenoxyacetic acid.

    PubMed

    Trivedi, Nikhilesh S; Mandavgane, Sachin A; Kulkarni, Bhaskar D

    2016-10-01

    The work highlights the utilization of an agricultural waste mustard plant ash (MPA) as a soil additive and an adsorbent. MPA was characterized by X-ray fluorescence (XRF), energy-dispersive X-ray spectroscopy (EDX), proximate analysis, CHNS analysis, Brunauer-Emmett-Teller (BET) surface area analysis, zeta potential measurements, Fourier transform infrared (FTIR), scanning electron microscopy (SEM), and transmission electron microscopy (TEM). XRF analysis confirmed the presence of CaO (31.35 %), K 2 O (18.55 %), and P 2 O 5 (6.99 %), all of which act as micronutrients to plants. EDX also confirms high amount of elemental O, Ca, K, and P. The adsorptive ability of MPA was investigated using a commonly used herbicide, 2,4-dichlorophenoxyacetic acid (2,4-D), as a representative chemical. Batch adsorption experiments were conducted to study the effect of different operational parameters such as adsorbent dose, initial 2,4-D concentration, contact time, and temperature on the adsorption process. Data from experiments were fitted to various kinetic and isothermal models. The pseudo-second-order kinetic model was found to show the best fit (R 2  > 0.99), with the highest k 2 value of the order 10 5 . Based on the study results, dosage of MPA/hectare for different crops has been recommended for effective removal of 2,4-D. To our knowledge, this is the first study in which MPA has been characterized in detail and investigated for dual applications (as an adsorbent and as a soil additive).

  15. Ballistic thermophoresis of adsorbates on free-standing graphene.

    PubMed

    Panizon, Emanuele; Guerra, Roberto; Tosatti, Erio

    2017-08-22

    The textbook thermophoretic force which acts on a body in a fluid is proportional to the local temperature gradient. The same is expected to hold for the macroscopic drift behavior of a diffusive cluster or molecule physisorbed on a solid surface. The question we explore here is whether that is still valid on a 2D membrane such as graphene at short sheet length. By means of a nonequilibrium molecular dynamics study of a test system-a gold nanocluster adsorbed on free-standing graphene clamped between two temperatures [Formula: see text] apart-we find a phoretic force which for submicron sheet lengths is parallel to, but basically independent of, the local gradient magnitude. This identifies a thermophoretic regime that is ballistic rather than diffusive, persisting up to and beyond a 100-nanometer sheet length. Analysis shows that the phoretic force is due to the flexural phonons, whose flow is known to be ballistic and distance-independent up to relatively long mean-free paths. However, ordinary harmonic phonons should only carry crystal momentum and, while impinging on the cluster, should not be able to impress real momentum. We show that graphene and other membrane-like monolayers support a specific anharmonic connection between the flexural corrugation and longitudinal phonons whose fast escape leaves behind a 2D-projected mass density increase endowing the flexural phonons, as they move with their group velocity, with real momentum, part of which is transmitted to the adsorbate through scattering. The resulting distance-independent ballistic thermophoretic force is not unlikely to possess practical applications.

  16. Ballistic thermophoresis of adsorbates on free-standing graphene

    PubMed Central

    Panizon, Emanuele; Guerra, Roberto; Tosatti, Erio

    2017-01-01

    The textbook thermophoretic force which acts on a body in a fluid is proportional to the local temperature gradient. The same is expected to hold for the macroscopic drift behavior of a diffusive cluster or molecule physisorbed on a solid surface. The question we explore here is whether that is still valid on a 2D membrane such as graphene at short sheet length. By means of a nonequilibrium molecular dynamics study of a test system—a gold nanocluster adsorbed on free-standing graphene clamped between two temperatures ΔT apart—we find a phoretic force which for submicron sheet lengths is parallel to, but basically independent of, the local gradient magnitude. This identifies a thermophoretic regime that is ballistic rather than diffusive, persisting up to and beyond a 100-nanometer sheet length. Analysis shows that the phoretic force is due to the flexural phonons, whose flow is known to be ballistic and distance-independent up to relatively long mean-free paths. However, ordinary harmonic phonons should only carry crystal momentum and, while impinging on the cluster, should not be able to impress real momentum. We show that graphene and other membrane-like monolayers support a specific anharmonic connection between the flexural corrugation and longitudinal phonons whose fast escape leaves behind a 2D-projected mass density increase endowing the flexural phonons, as they move with their group velocity, with real momentum, part of which is transmitted to the adsorbate through scattering. The resulting distance-independent ballistic thermophoretic force is not unlikely to possess practical applications. PMID:28774954

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

    SciTech Connect

    Hong, Sung -Young; Xu, Pan; Camillone, Nina R.

    Here, 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 probabilitymore » 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, η el, that decreases with binding site in the order: three-fold hollow > bridge and near bridge > top site. This weakening of η el 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.« less

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

    SciTech Connect

    Hong, Sung-Young; Camillone, Nina R.; Camillone, Nicholas, E-mail: nicholas@bnl.gov

    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 increasesmore » 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, η{sub el}, that decreases with binding site in the order: three-fold hollow > bridge and near bridge > top site. This weakening of η{sub el} 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.« less

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

    DOE PAGES

    Hong, Sung -Young; Xu, Pan; Camillone, Nina R.; ...

    2016-07-01

    Here, 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 probabilitymore » 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, η el, that decreases with binding site in the order: three-fold hollow > bridge and near bridge > top site. This weakening of η el 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.« less

  20. Silica/graphene oxide nanocomposites: Potential adsorbents for solid phase extraction of trace aflatoxins in cereal crops coupled with high performance liquid chromatography.

    PubMed

    Yu, Li; Ma, Fei; Ding, Xiaoxia; Wang, Hengling; Li, Peiwu

    2018-04-15

    Graphene oxide wrapped silica nanocomposites were synthesized and selected as solid phase extraction adsorbents for high performance liquid chromatography analysis of aflatoxins. The major parameters affecting extraction efficiency were optimized, including the amount of adsorbents, extraction time and desorption conditions. The limit of detections and the limit of quantifications were from 0.1 to 0.3 µg/kg and from 0.3 to 1.0 µg/kg, respectively. The recoveries of aflatoxins in the spiked maize and rice samples were in the range of 76.8-104.7% and 81.1-106.9%, respectively, and with the RSDs less than 12.4%. The proposed method was proven to be simple, rapid and reliable for routine analysis of aflatoxins in crops. Copyright © 2017 Elsevier Ltd. All rights reserved.

  1. Hurricane Isabel, Amount of Atmospheric Water Vapor Observed By AIRS

    NASA Image and Video Library

    2003-09-20

    This false-color image shows the amount of atmospheric water vapor observed by AIRS two weeks prior to the passage of Hurricane Isabel, and then when it was a Category 5 storm. The region shown includes parts of South America and the West Indies. Puerto Rico is the large island below the upper left corner. Total water vapor represents the depth of a layer if all the water vapor in the atmosphere were to condense and fall to the surface. The color bar on the right sides of the plots give the thickness of this layer in millimeters (mm). The first image, from August 28, shows typical tropical water vapor amounts over the ocean: between roughly 25 and 50 mm, or 1 to 2 inches. The highest values of roughly 80 mm, seen as a red blob over South America, corresponds to intense thunderstorms. Thunderstorms pull in water vapor from surrounding regions and concentrate it, with much of it then falling as rain. http://photojournal.jpl.nasa.gov/catalog/PIA00430

  2. Does the amount of school choice matter for student engagement?

    PubMed Central

    Vaughn, Michael G.; Witko, Christopher

    2013-01-01

    School choice may increase student engagement by enabling students to attend schools that more closely match their needs and preferences. But this effect on engagement may depend on the characteristics of the choices available. Therefore, we consider how the amount of educational choice of different types in a local educational marketplace affects student engagement using a large, national population of 8th grade students. We find that more choice of regular public schools in the elementary and middle school years is associated with a lower likelihood that students will be severely disengaged in eighth grade, and more choices of public schools of choice has a similar effect but only in urban areas. In contrast, more private sector choice does not have such a general beneficial effect. PMID:23682202

  3. 20 CFR 416.538 - Amount of underpayment or overpayment.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... difference between the amount paid to a recipient and the amount of payment actually due such recipient for a... difference between the amount paid and the amount actually due for that month. The period ends with the month... require no change with respect to a prior determination of overpayment or to the period relating to such...

  4. Developments toward large-scale bacterial bioprocesses in the presence of bulk amounts of organic solvents.

    PubMed

    Schmid, A; Kollmer, A; Mathys, R G; Witholt, B

    1998-08-01

    Many pseudomonads and other bacteria can grow on aliphatic and aromatic hydrocarbons that occur in the environment. We are examining the potential of such organisms as biocatalysts for the oxidation of a variety of substituted aliphatic and aromatic compounds. To attain a high production rate of oxidation products via such biotransformations, we have focused on two-liquid phase culture systems. In these systems, cells are grown in liquid media consisting of an aqueous phase containing water-soluble growth substrates and droplets of a water-immicible organic solvent containing bioconversion substrates and products. For industrial applications of such two-liquid phase processes, several questions remain. What are the maximum rates at which apolar compounds can be transferred from the apolar phase to cells growing in the aqueous phase, i.e., what are the maximum space-time yields attainable in two-liquid phase fermentations under practical conditions? What does an efficient downstream processing of two-liquid phase medium involve? What safety regimes should be considered in working with flammable organic solvents? Can elevated pressure be used to increase oxygen transfer? Based on answers to these questions, we have recently developed a high-pressure, explosion-proof bioreactor system with Bioengineering AG (Wald, Switzerland), which will be installed in our pilot plant and used to explore two-liquid phase bioconversions at a pilot scale.

  5. Removal of salicylic acid as an emerging contaminant by a polar nano-dendritic adsorbent from aqueous media.

    PubMed

    Arshadi, M; Mousavinia, F; Abdolmaleki, M K; Amiri, M J; Khalafi-Nezhad, A

    2017-05-01

    A polar nano-dendritic adsorbent containing amine groups (SAPAMAA) was synthesized onto the nanoparticles of SiO 2 Al 2 O 3 and its uptake of salicylic acid (SA) from the synthetic and real water was investigated. The synthesized nanomaterials were fully studied by nuclear magnetic resonance spectrum ( 1 H NMR and 13 C NMR), Fourier transform infrared spectroscopy (FT-IR), zeta potential (ζ), inductively coupled plasma atomic emission spectroscopy (ICP-AES), scanning electron microscopy (SEM), transmission electron microscopy (TEM), Brunauer-Emmett-Teller (BET) and elemental analysis. Various parameters such as the effect of the contact time, adsorbent dosage, initial SA concentrations, effect of solution's temperature, interfering ions, the hydrophobicity of the nanoadsorbent and initial pH were assessed. The contact time to approach equilibrium for higher adsorption was 15min (252.8mgg -1 ). The isotherms could be fitted by Sips model (with the average relative error of 6.6) and the kinetic data could be characterized by pseudo-second-order rate equation (with the average relative error of 13.0), implying chemical adsorption as the ratelimiting step of uptake process which was supported by the experimental data from the effect of interfering ions, zeta potential, and altering of the adsorbent's hydrophobicity. The uptake capacities decreased with temperature increasing, and showed that the uptake of SA was chemically exothermic in nature between 15 and 80°C. In addition, the spent SAPAMAA could be regenerated by the removal of adsorbed SA with NaOH and ethanol to regain the original SAPAMAA, the regenerated SAPAMAA also exhibited the high adsorption capacity after 10 runs. Moreover, SAPAMAA could also be applied to uptake SA from a real water (Anzali lagoon water). We envisage that the prepared nano-dendritic with remarkable characteristics such as environmentally friendly, low-cost, easy preparation in large quantity, high mechanical and chemical stability

  6. Potential of polyaniline modified clay nanocomposite as a selective decontamination adsorbent for Pb(II) ions from contaminated waters; kinetics and thermodynamic study.

    PubMed

    Piri, Somayeh; Zanjani, Zahra Alikhani; Piri, Farideh; Zamani, Abbasali; Yaftian, Mohamadreza; Davari, Mehdi

    2016-01-01

    Nowadays significant attention is to nanocomposite compounds in water cleaning. In this article the synthesis and characterization of conductive polyaniline/clay (PANI/clay) as a hybrid nanocomposite with extended chain conformation and its application for water purification are presented. Clay samples were obtained from the central plain of Abhar region, Abhar, Zanjan Province, Iran. Clay was dried and sieved before used as adsorbent. The conductive polyaniline was inflicted into the layers of clay to fabricate a hybrid material. The structural properties of the fabricated nanocomposite are studied by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR) and scanning electron microscope (SEM). The elimination process of Pb(II) and Cd(II) ions from synthetics aqueous phase on the surface of PANI/clay as adsorbent were evaluated in batch experiments. Flame atomic absorption instrument spectrophotometer was used for determination of the studied ions concentration. Consequence change of the pH and initial metal amount in aqueous solution, the procedure time and the used adsorbent dose as the effective parameters on the removal efficiency was investigated. Surface characterization was exhibited that the clay layers were flaked in the hybrid nanocomposite. The results show that what happen when a nanocomposite polyaniline chain is inserted between the clay layers. The adsorption of ions confirmed a pH dependency procedure and a maximum removal value was seen at pH 5.0. The adsorption isotherm and the kinetics of the adsorption processes were described by Temkin model and pseudo-second-order equation. Time of procedure, pH and initial ion amount have a severe effect on adsorption efficiency of PANI/clay. By using suggested synthesise method, nano-composite as the adsorbent simply will be prepared. The prepared PANI/clay showed excellent adsorption capability for decontamination of Pb ions from contaminated water. Both of suggested synthesise and

  7. Cadmium hydroxide nanowire loaded on activated carbon as efficient adsorbent for removal of Bromocresol Green

    NASA Astrophysics Data System (ADS)

    Ghaedi, Mehrorang; Khajesharifi, Habibollah; Hemmati Yadkuri, Amin; Roosta, Mostafa; Sahraei, Reza; Daneshfar, Ali

    2012-02-01

    In the present research, cadmium hydroxide nanowire loaded on activated carbon (Cd(OH) 2-NW-AC) was synthesized and characterized. This new adsorbent was applied for the removal of Bromocresol Green (BCG) molecules from aqueous solutions. The influence of effective variables such as solution pH, contact time, initial BCG concentration, amount of Cd(OH) 2-NW-AC and temperature on the adsorption efficiency of BCG in batch system was examined. During all experiments BCG contents were determined by UV-Vis spectrophotometer. Fitting the experimental data to different kinetic models including pseudo-first-order, pseudo-second-order, Elovich and intra-particle diffusion kinetic models show the suitability of the pseudo-second-order kinetic model to interpret in the experimental data. Equilibrium isotherm studies were examined by application of different conventional models such as Langmuir, Freundlich and Tempkin models to explain the experimental data. Based on considering R2 value as criterion the adsorption data well fitted to Langmuir model with maximum adsorption capacity of 108.7 mg g -1. Thermodynamic parameters (Gibb's free energy, entropy and enthalpy) of adsorption were calculated according to general procedure to take some information about the on-going adsorption process. The high negative value of Gibb's free energy and positive value of enthalpy show the feasibility and endothermic nature of adsorption process.

  8. Cadmium hydroxide nanowire loaded on activated carbon as efficient adsorbent for removal of Bromocresol Green.

    PubMed

    Ghaedi, Mehrorang; Khajesharifi, Habibollah; Hemmati Yadkuri, Amin; Roosta, Mostafa; Sahraei, Reza; Daneshfar, Ali

    2012-02-01

    In the present research, cadmium hydroxide nanowire loaded on activated carbon (Cd(OH)(2)-NW-AC) was synthesized and characterized. This new adsorbent was applied for the removal of Bromocresol Green (BCG) molecules from aqueous solutions. The influence of effective variables such as solution pH, contact time, initial BCG concentration, amount of Cd(OH)(2)-NW-AC and temperature on the adsorption efficiency of BCG in batch system was examined. During all experiments BCG contents were determined by UV-Vis spectrophotometer. Fitting the experimental data to different kinetic models including pseudo-first-order, pseudo-second-order, Elovich and intra-particle diffusion kinetic models show the suitability of the pseudo-second-order kinetic model to interpret in the experimental data. Equilibrium isotherm studies were examined by application of different conventional models such as Langmuir, Freundlich and Tempkin models to explain the experimental data. Based on considering R(2) value as criterion the adsorption data well fitted to Langmuir model with maximum adsorption capacity of 108.7 mg g(-1). Thermodynamic parameters (Gibb's free energy, entropy and enthalpy) of adsorption were calculated according to general procedure to take some information about the on-going adsorption process. The high negative value of Gibb's free energy and positive value of enthalpy show the feasibility and endothermic nature of adsorption process. Copyright © 2011 Elsevier B.V. All rights reserved.

  9. Spectroscopic studies of conformational changes of β-lactoglobulin adsorbed on gold nanoparticle surfaces.

    PubMed

    Winuprasith, Thunnalin; Suphantharika, Manop; McClements, David Julian; He, Lili

    2014-02-15

    In this work, we investigated the conformational changes of a globular protein (β-lactoglobulin, β-lg) coated on the surface of 200 nm gold nanoparticles (GNPs) using a number of analytical techniques: dynamic light scattering (DLS); particle electrophoresis (ζ-potential); localized surface plasmon resonance (LSPR) spectroscopy; transmission electron microscopy (TEM); and surface-enhanced Raman scattering (SERS). The β-lg (pH 3) concentration had a pronounced effect on the aggregation and surface charge of β-lg-coated GNPs. The surface charge of GNPs changed from negative to positive as increasing amounts of β-lg molecule were added, indicating that the globular protein molecules adsorbed to the surfaces of the particles. Extensive particle aggregation occurred when β-lg did not saturate the GNP surfaces, which was attributed to electrostatic bridging flocculation. Modifications in LSPR and SERS spectra after addition of β-lg to the GNP suspensions supported the adsorption of β-lg to the particle surfaces. Moreover, SERS highlighted the importance of a number of specific molecular groups in the binding interaction, and suggested conformational changes of the globular protein after adsorption. This research provides useful information for characterizing and understanding the interactions between globular proteins and colloidal particles. Copyright © 2013 Elsevier Inc. All rights reserved.

  10. Ca and Fe modified biochars as adsorbents of arsenic and chromium in aqueous solutions.

    PubMed

    Agrafioti, Evita; Kalderis, Dimitrios; Diamadopoulos, Evan

    2014-12-15

    This work investigated the production of Ca and Fe modified biochars in order to use them for the removal of arsenic As(V) and chromium Cr(VI) from aqueous solutions. Rice husk was impregnated with CaO at an impregnation ratio 0.114, while both rice husk and the organic fraction of municipal solid wastes were impregnated with Fe(0) and Fe(3+) at impregnation ratios 0.114 and 0.23. The modified biochars exhibited high As(V) removal capacity (>95%), except for the case of rice husk impregnated with Fe(0), whose removal capacity reached only 58%. All modified biochars exhibited much better As(V) removal capacity compared to the non-impregnated biochars. However, the Cr(VI) removal rates were not as high as the As(V) ones. The maximum Cr(VI) removal was observed in the case of rice husk biochar impregnated with 2.3% w/w Fe(3+), whereas the majority of impregnation agents examined did not manage to enhance the biochars' Cr(VI) removal ability. The equilibrium study showed that the Freundlich model can adequately describe the sorption process for the majority of samples examined. Analysis of the amount of Fe present in the equilibrium solutions suggested that the main mechanisms of As(V) and Cr(VI) removal were possibly metal precipitation and electrostatic interactions between the modified biochars and the adsorbate. Copyright © 2014 Elsevier Ltd. All rights reserved.

  11. Investigation of 2,4-dinitrophenylhydrazine impregnated adsorbent tubes for the collection of airborne aldehydes

    SciTech Connect

    Holdren, M.W.; Smith, D.L.; Russell, N.K.

    1988-06-01

    The objective of the study was to investigate the use of 2,4-dinitrophenylhydrazine (DNPH) impregnated adsorbents for sampling airborne aldehydes. Experimental results using a 17 cu m environmental chamber and various spiked amounts of aldehyde material (low ppb levels) showed that the DNPH coated cartridge and the DNPH/acetonitrile impinger methods gave equivalent results. Blank levels of the DNPH-coated cartridges were studied as a function of storage time using various containers and temperature conditions. Canisters pressurized with zero-grade nitrogen provided the best storage device. Lower blank levels were also obtained when the cartridges were stored at lower temperatures. Blank levels appear tomore » equilibrate after six days of storage. To assure that quality data will be obtained, cartridges should be grouped according to batch number and blank levels should be determined prior to any field monitoring effort. Blank cartridge levels should be an order of magnitude lower than sample cartridge level. High performance liquid chromatography with UV detection proved to be a sensitive and stable analytical method for the DNPH derivatives.« less

  12. Utilization Chitosan-p-t-Butylcalix[4]Arene for Red MX 8B Adsorbent

    NASA Astrophysics Data System (ADS)

    Handayani, D. S.; Kusumaningsih, T.; Hak, L. A.

    2017-02-01

    Adsorption of Procion Red MX 8B using chitosan dan chitosan-linked p-t-butylcalix[4]arene has been done. The research aimed to understand the adsorption of Procion Red MX 8B using chitosan p-t-butylcalix[4]arene compared to ordinary chitosan. The research was conducted in a batch process varying in pH, contact time and initial concentration of the Procion Red MX 8B. The amount of dye adsorbed was determined using UV-Vis spectrophotometer and the adsorben was characterized using FTIR and SEM-EDX spectrophotometer. The result showed that the optimum condition was achieved when the pH was set at 4, contact time 135 minutes and initial concentration at 200 ppm. The kinetic analysis showed that the adsorption followed Ho kinetic model and pseudo second order with the adsorption rate constant was 3.69×10-3 g/mg.minute and 2.03×10-3 g/mg.minute. The isotherm analysis showed that the adsorption process tend to occur following the Langmuir model with maximum capacity for chitosan and chitosan-linked p-t-butylcalix[4]arene 136.09 mg/g and 147.35 mg/g respectively. The adsorption energy of chitosan and chitosan-linked p-t-butylcalix[4]arene at 30.53 kJ/mole and 33.65 kJ/mole.

  13. Impact of Bioreduction on Remobilization of Adsorbed Cadmium on Iron Minerals in Anoxic Condition.

    PubMed

    Ghorbanzadeh, Nasrin; Lakzian, Amir; Halajnia, Akram; Choi, Ui-Kyu; Kim, Ki-Hyun; Kim, Jong-Oh; Kurade, Mayur; Jeon, Byong-Hun

    2017-06-01

      The impact of bioreduction on the remobilization of adsorbed cadmium Cd(II) on minerals, including hematite, goethite, and two iron(III)-rich clay minerals nontronites (NAU-1 and NAU-2) under anoxic conditions was investigated. Langmuir isotherm equation better described the sorption of Cd(II) onto the all minerals. The maximum adsorption capacity was 6.2, 18.1, 3.6, and 4 mg g-1 for hematite, goethite, NAU-1 and NAU-2, respectively. The desorption of Cd(II) was due to the production of Fe(II) as a result of bioreduction of structural Fe(III) in the minerals by Shewanella putrefaciens. The bioreduction of Cd(II)-loaded Fe(III) minerals was negligible during the initial 5 days followed by a rapid increase up to 20 days. The amount of Cd(II) in solution phase at the end of 30 days increased up to 0.07 mmol L-1 for hematite, NAU-1, and NAU-2 and 0.02 mmol L-1 for goethite. The X-ray diffraction study showed negligible changes in bioreduced minerals phases.

  14. MUTAGENIC CHARACTERISTICS OF RIVER WATERS FLOWING THROUGH LARGE METROPOLITAN AREAS IN NORTH AMERICA

    EPA Science Inventory

    Mutagenic characteristics of river waters flowing through large metropolitan areas in North America

    The hanging technique using blue rayon, which specifically adsorbs mutagens with multicyclic planar structures, has the advantages over most conventional methods of not havi...

  15. Highly selective and efficient removal of lead with magnetic nano-adsorbent: Multivariate optimization, isotherm and thermodynamic studies.

    PubMed

    Khani, Rouhollah; Sobhani, Sara; Beyki, Mostafa Hossein

    2016-03-15

    2-Hydroxyethylammonium sulfonate immobilized on γ-Fe2O3 nanoparticles (γ-Fe2O3-2-HEAS) was synthesized by the reaction of n-butylsulfonated γ-Fe2O3 with ethanolamine. The structure of the resulting product was confirmed by fourier transform infrared (FT-IR) spectra, X-ray diffraction (XRD) spectrometry, transmission electron microscopy (TEM), thermogravimetric analysis (TGA), elemental analysis, N2 adsorption-desorption and vibrating sample magnetometer (VSM) techniques. The supported ionic liquid on γ-Fe2O3 was applied as a new and green adsorbent to remove Pb(II) from aqueous solution. The effect of adsorption parameters such as pH, shaking time and amount of the adsorbent were investigated using two level three factor (2(3)) full factorial central composite design with the help of Design-Expert, Stat-Ease Inc. version 9.0 software. The significance of independent variables and their interactions were tested by means of the analysis of variance (ANOVA) with 95% confidence limits (α=0.05). The thermodynamic parameters of the adsorption process are estimated. It is found that the process is exothermic and spontaneous. The Langmuir and Freundlich models have been also applied to evaluate the removal efficiency and the data were correlated well with the Freundlich model. Copyright © 2015 Elsevier Inc. All rights reserved.

  16. Multi-pesticides residue analysis of grains using modified magnetic nanoparticle adsorbent for facile and efficient cleanup.

    PubMed

    Liu, Zhenzhen; Qi, Peipei; Wang, Xiangyun; Wang, Zhiwei; Xu, Xiahong; Chen, Wenxue; Wu, Liyu; Zhang, Hu; Wang, Qiang; Wang, Xinquan

    2017-09-01

    A facile, rapid sample pretreatment method was developed based on magnetic nanoparticles for multi-pesticides residue analysis of grains. Magnetite (Fe 3 O 4 ) nanoparticles modified with 3-(N,N-diethylamino)propyltrimethoxysilane (Fe 3 O 4 -PSA) and commercial C18 were selected as the cleanup adsorbents to remove the target interferences of the matrix, such as fatty acids and non-polar compounds. Rice was used as the representative grain sample for method optimization. The amount of Fe 3 O 4 -PSA and C18 were systematically investigated for selecting the suitable purification conditions, and the simultaneous determination of 50 pesticides and 8 related metabolites in rice was established by liquid chromatography-tandem mass spectrometry. Under the optimal conditions, the method validation was performed including linearity, sensitivity, matrix effect, recovery and precision, which all satisfy the requirement for pesticides residue analysis. Compared to the conventional QuEChERS method with non-magnetic material as cleanup adsorbent, the present method can save 30% of the pretreatment time, giving the high throughput analysis possible. Copyright © 2017 Elsevier Ltd. All rights reserved.

  17. Negative chromatography purification of hepatitis B virus-like particles using poly(oligo(ethylene glycol) methacrylate) grafted cationic adsorbent.

    PubMed

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

    2015-10-09

    Poly(oligo(ethylene glycol) methacrylate) (POEGMA), an inert polymer was grafted onto an anion exchange adsorbent for the exclusion of relatively larger hepatitis B virus-like particles (HB-VLPs) from the anion exchange ligand (Q) and at the same time this process allowed the selective adsorption of smaller size Escherichia coli host cell proteins (HCPs). The chain lengths of the POEGMA grafted were modulated by varying the amount of monomers used in the polymer grafting. The purification factor and yield of the HB-VLPs obtained from the flow-through of negative chromatography were 2.3 and 66.0±3.1%, respectively, when shorter chain length of POEGMA (SQ) was grafted. Adsorbent grafted with longer chain of POEGMA (LQ) excluded some HCPs that are larger in size together with the HB-VLPs, reducing the purity of the recovered HB-VLPs. Further heat-treatment of the flow-through pool from SQ followed by centrifugation increased the purity of heat stable HB-VLPs to 87.5±1.1%. Heat-treatment of the flow through sample resulted in thermal denaturation and aggregation of HCPs, while the heat stable HB-VLPs still remained intact as observed under a transmission electron microscope. The performance of the negative chromatography together with heat treatment in the purification of HB-VLPs is far better than the reported bind-and-elute techniques. Copyright © 2015 Elsevier B.V. All rights reserved.

  18. Magnetic hydroxyapatite nanoparticles: an efficient adsorbent for the separation and removal of nitrate and nitrite ions from environmental samples.

    PubMed

    Ghasemi, Ensieh; Sillanpää, Mika

    2015-01-01

    A novel type of magnetic nanosorbent, hydroxyapatite-coated Fe2O3 nanoparticles was synthesized and used for the adsorption and removal of nitrite and nitrate ions from environmental samples. The properties of synthesized magnetic nanoparticles were characterized by scanning electron microscopy, Fourier transform infrared spectroscopy, and X-ray powder diffraction. After the adsorption process, the separation of γ-Fe2O3@hydroxyapatite nanoparticles from the aqueous solution was simply achieved by applying an external magnetic field. The effects of different variables on the adsorption efficiency were studied simultaneously using an experimental design. The variables of interest were amount of magnetic hydroxyapatite nanoparticles, sample volume, pH, stirring rate, adsorption time, and temperature. The experimental parameters were optimized using a Box-Behnken design and response surface methodology after a Plackett-Burman screening design. Under the optimum conditions, the adsorption efficiencies of magnetic hydroxyapatite nanoparticles adsorbents toward NO3(-) and NO2(-) ions (100 mg/L) were in the range of 93-101%. The results revealed that the magnetic hydroxyapatite nanoparticles adsorbent could be used as a simple, efficient, and cost-effective material for the removal of nitrate and nitrite ions from environmental water and soil samples. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  19. Evaluation of mixed valent iron oxides as reactive adsorbents for arsenic removal.

    PubMed

    Mishra, Dhananjay; Farrell, James

    2005-12-15

    The objective of this research was to determine if Fe(II)-bearing iron oxides generate ferric hydroxides at sufficient rates for removing low levels of arsenic in packed-bed reactors, while at the same time avoiding excessive oxide production that contributes to bed clogging in oxygenated waters. Column experiments were performed to determine the effectiveness of three media for arsenic removal over a range in empty bed contact times, influent arsenic concentrations, dissolved oxygen (DO) levels, and solution pH values. Corrosion rates of the media as a function of the water composition were determined using batch and electrochemical methods. Rates of arsenic removal were first order in the As(V) concentration and were greater for media with higher corrosion rates. As(V) removal increased with increasing DO levels primarily due to faster oxidation of the Fe2+ released by media corrosion. To obtain measurable amounts of arsenic removal in 15 mM NaCl electrolyte solutions containing 50 microg/L As(V), the rate of Fe2+ released by the media needed to be at least 15 times greater than the As(V) feed rate into the column. In waters containing 30 mg/L of silica and 50 microg/L of As(V), measurable amounts of arsenic removal were obtained only for Fe2+ release rates that were at least 200 times greater than the As(V) feed rate. Although all columns showed losses in hydraulic conductivity overthe course of 90 days of operation, the conductivity values remained high, and the losses could be reversed by backwashing the media. The reaction products produced by the media in domestic tap water had average As-to-Fe ratios that were approximately 25% higher than those for a commercially available adsorbent.

  20. Removal of Heavy Metal Contamination from Peanut Skin Extracts by Waste Biomass Adsorbents

    USDA-ARS?s Scientific Manuscript database

    Each year, 3.6 million pounds of peanuts are harvested in the United States. Consequent processing, however, generates large amounts of waste biomass as only the seed portion of the fruit is consumed. The under-utilization of waste biomass is a lost economic opportunity to the industry. In particula...

  1. Empirical relationships between tree fall and landscape-level amounts of logging and fire

    PubMed Central

    Blanchard, Wade; Blair, David; McBurney, Lachlan; Stein, John; Banks, Sam C.

    2018-01-01

    Large old trees are critically important keystone structures in forest ecosystems globally. Populations of these trees are also in rapid decline in many forest ecosystems, making it important to quantify the factors that influence their dynamics at different spatial scales. Large old trees often occur in forest landscapes also subject to fire and logging. However, the effects on the risk of collapse of large old trees of the amount of logging and fire in the surrounding landscape are not well understood. Using an 18-year study in the Mountain Ash (Eucalyptus regnans) forests of the Central Highlands of Victoria, we quantify relationships between the probability of collapse of large old hollow-bearing trees at a site and the amount of logging and the amount of fire in the surrounding landscape. We found the probability of collapse increased with an increasing amount of logged forest in the surrounding landscape. It also increased with a greater amount of burned area in the surrounding landscape, particularly for trees in highly advanced stages of decay. The most likely explanation for elevated tree fall with an increasing amount of logged or burned areas in the surrounding landscape is change in wind movement patterns associated with cutblocks or burned areas. Previous studies show that large old hollow-bearing trees are already at high risk of collapse in our study area. New analyses presented here indicate that additional logging operations in the surrounding landscape will further elevate that risk. Current logging prescriptions require the protection of large old hollow-bearing trees on cutblocks. We suggest that efforts to reduce the probability of collapse of large old hollow-bearing trees on unlogged sites will demand careful landscape planning to limit the amount of timber harvesting in the surrounding landscape. PMID:29474487

  2. Empirical relationships between tree fall and landscape-level amounts of logging and fire.

    PubMed

    Lindenmayer, David B; Blanchard, Wade; Blair, David; McBurney, Lachlan; Stein, John; Banks, Sam C

    2018-01-01

    Large old trees are critically important keystone structures in forest ecosystems globally. Populations of these trees are also in rapid decline in many forest ecosystems, making it important to quantify the factors that influence their dynamics at different spatial scales. Large old trees often occur in forest landscapes also subject to fire and logging. However, the effects on the risk of collapse of large old trees of the amount of logging and fire in the surrounding landscape are not well understood. Using an 18-year study in the Mountain Ash (Eucalyptus regnans) forests of the Central Highlands of Victoria, we quantify relationships between the probability of collapse of large old hollow-bearing trees at a site and the amount of logging and the amount of fire in the surrounding landscape. We found the probability of collapse increased with an increasing amount of logged forest in the surrounding landscape. It also increased with a greater amount of burned area in the surrounding landscape, particularly for trees in highly advanced stages of decay. The most likely explanation for elevated tree fall with an increasing amount of logged or burned areas in the surrounding landscape is change in wind movement patterns associated with cutblocks or burned areas. Previous studies show that large old hollow-bearing trees are already at high risk of collapse in our study area. New analyses presented here indicate that additional logging operations in the surrounding landscape will further elevate that risk. Current logging prescriptions require the protection of large old hollow-bearing trees on cutblocks. We suggest that efforts to reduce the probability of collapse of large old hollow-bearing trees on unlogged sites will demand careful landscape planning to limit the amount of timber harvesting in the surrounding landscape.

  3. REGENERATION AND REACTIVATION OF CARBON ADSORBENTS BY RADIO FREQUENCY INDUCTION HEATING

    EPA Science Inventory

    1. Electrical Properties of Adsorbents: We measured the electric permittivity of four commercially available carbon adsorbents (supplied by Wesvaco Inc) over the radio frequency range (1 to 40 MHz). Westvaco is by far the largest volume supplier of activated carbon...

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

    PubMed

    Lata, Sneh; Samadder, S R

    2016-01-15

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

  5. Rigorous Mathematical Modeling of Adsorption System with Electrothermal Regeneration of the Used Adsorbent

    DTIC Science & Technology

    2006-12-01

    DISTRIBUTION STATEMENT. ________//signature//________________ ________//signature//________________ PATRICK D. SULLIVAN, Ph.D., P.E. SANDRA R ...adsorber, at r =1.24 cm: (a) gas phase; (b) solid phase..................................................................................... 30 46 The...34 57 Axial profiles of the gas velocity during adsorption in the 2-cartridge adsorber at r =1.25cm..... 34 60

  6. Towards understanding KOH conditioning of amidoxime-based oolymer adsorbents for sequestering uranium from seawater

    SciTech Connect

    Pan, Horng-Bin; Kuo, Li-Jung; Wood, Jordana

    2015-11-17

    Conditioning of polymer fiber adsorbents grafted with amidoxime and carboxylic acid groups is necessary to make the materials hydrophilic for sequestering uranium from seawater. In this paper, spectroscopic techniques were employed to study the effectiveness of the traditional KOH conditioning method (2.5% KOH at 80⁰C) on recently developed high-surface-area amidoxime-based polymer fiber adsorbents developed at Oak Ridge National Laboratory. FTIR spectra reveal that the KOH conditioning process removes the proton from the carboxylic acids and also converts the amidoxime groups to carboxylate groups in the adsorbent. With prolonged KOH treatment (>1 hr) at 80⁰C, physical damage to the adsorbent materialmore » occurs which can lead to a significant reduction in the adsorbent's uranium adsorption capability in real seawater during extended exposure times (>21 days). The physical damage to the adsorbent can be minimized by lowering KOH conditioning temperature. For the high-surface-area amidoxime-based adsorbents, 20 min of conditioning in 2.5% KOH at 80⁰C or 1 hr of conditioning in 2.5% KOH at 60⁰C appears sufficient to achieve de-protonation of the carboxylic acid with minimal harmful effects to the adsorbent material. Lastly, the use of NaOH instead of KOH can also reduce the cost of the base treatment process required for conditioning the amidoxime-based sorbents with minimal loss of adsorption capacity (≤7%).« less

  7. Insight into Multifunctional Reactive Adsorbents: Engaging Chemistry, Porosity, Photoactivity and Conductivity into Decontamination Process

    DTIC Science & Technology

    2017-06-07

    AUTHORS 7. PERFORMING ORGANIZATION NAMES AND ADDRESSES 15. SUBJECT TERMS b. ABSTRACT 2. REPORT TYPE 17. LIMITATION OF ABSTRACT 15. NUMBER OF PAGES 5d...Insight Into Multifunctional Reactive Adsorbents: Engaging Chemistry , Porosity, Photoactivity and Conductivity into Decontamination Process The...Office P.O. Box 12211 Research Triangle Park, NC 27709-2211 CWA decontamination, multifunctional adsorbents, porosity, surface chemistry

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

    PubMed

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

    2017-10-01

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

  9. Evaluation of Aluminium Dross as Adsorbent for Removal of Carcinogenic Congo Red Dye in Wastewater

    NASA Astrophysics Data System (ADS)

    Zakaria, Mohamad Zulfika Hazielim b.; Zauzi, Nur Syuhada Ahmad; Baini, Rubiyah; Sutan, Norsuzailina Mohamed; Rezaur Rahman, Md

    2017-06-01

    In this study, aluminium dross waste generated from aluminium smelting industries was employed as adsorbent in removing of congo red dye in aqueous solution. The raw aluminium dross as adsorbent was characterized using Scanning Electron Microscope (SEM), Brunauer-Emmett-Teller (BET) for surface area and X-Ray Fluorescence (XRF) Spectroscopy. Adsorption experiments were carried out by batch system at different adsorbent mass, pH, and initial dye concentration. The results showed that the per cent removal of dye increased as adsorbent mass increased. It was found that 0.4 gram of adsorbent can remove approximately 100 % of dye at pH 9 for dye concentration 20 and 40 ppm. Therefore, it can be concluded that raw aluminium dross without undergone any treatment can be effectively used for the adsorption of congo red in textile wastewater related industries.

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

    NASA Astrophysics Data System (ADS)

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

    2017-06-01

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

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

    SciTech Connect

    Pan, Horng-Bin; Wai, Chien M.; Kuo, Li-Jung

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

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

    SciTech Connect

    Pan, Horng-Bin; Wai, Chien M.; Kuo, Li-Jung

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

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

    DOE PAGES

    Pan, Horng-Bin; Wai, Chien M.; Kuo, Li-Jung; ...

    2017-05-02

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

  14. Synthesis of Composite Adsorbent from Calcium Carbonate and Cocos Nucifera Carbon Powder Crosslinked with Biopolymer Matrix

    NASA Astrophysics Data System (ADS)

    Kamaruddin, M. A.; Bakri, M. M. A.; Norashiddin, F. A.; Zawawi, M. H.; Zainol, M. R. R. A.

    2018-03-01

    The use of coconut shell based adsorbent for removing various pollutants from wastewater offers attractive advantages such as exceptional adsorption capacity with larger surface area, low-cost and biocompatibility for a wide range of pollutants. The same goes for calcium carbonate based adsorbent, which provides better removal for metals ions through precipitation method. In fact, recycling of waste material is considered environmentally preferable and is supported by public opinion and government policy. However, because of unit operations mechanisms and effectiveness are different to one another in downstream process, it is quite difficult to provide good adsorbent that exhibits dual attributes of hydrophobic and hydrophilic characters. This paper provides brief process for sintering of composite adsorbent for separation and purification of industrial wastewater application. Characterization was performed by physical and chemical approach. Results prove that the inclusion of biopolymer as composite binder improved mechanical properties of the composite adsorbent.

  15. Using GRACE to constrain precipitation amount over cold mountainous basins

    NASA Astrophysics Data System (ADS)

    Behrangi, Ali; Gardner, Alex S.; Reager, John T.; Fisher, Joshua B.

    2017-01-01

    Despite the importance for hydrology and climate-change studies, current quantitative knowledge on the amount and distribution of precipitation in mountainous and high-elevation regions is limited due to instrumental and retrieval shortcomings. Here by focusing on two large endorheic basins in High Mountain Asia, we show that satellite gravimetry (Gravity Recovery and Climate Experiment (GRACE)) can be used to provide an independent estimate of monthly accumulated precipitation using mass balance equation. Results showed that the GRACE-based precipitation estimate has the highest agreement with most of the commonly used precipitation products in summer, but it deviates from them in cold months, when the other products are expected to have larger errors. It was found that most of the products capture about or less than 50% of the total precipitation estimated using GRACE in winter. Overall, Global Precipitation Climatology Project (GPCP) showed better agreement with GRACE estimate than other products. Yet on average GRACE showed 30% more annual precipitation than GPCP in the study basins. In basins of appropriate size with an absence of dense ground measurements, as is a typical case in cold mountainous regions, we find GRACE can be a viable alternative to constrain monthly and seasonal precipitation estimates from other remotely sensed precipitation products that show large bias.

  16. Heavy metals in Iberian soils: Removal by current adsorbents/amendments and prospective for aerogels.

    PubMed

    Vareda, João P; Valente, Artur J M; Durães, Luisa

    2016-11-01

    Heavy metals are dangerous pollutants that in spite of occurring naturally are released in major amounts to the environment due to anthropogenic activities. After being released in the environment, the heavy metals end up in the soils where they accumulate as they do not degrade, adversely affecting the biota. Because of the dynamic equilibria between soil constituents, the heavy metals may be present in different phases such as the solid phase (immobilized contaminants) or dissolved in soil solution. The latter form is the most dangerous because the ions are mobile, can leach and be absorbed by living organisms. Different methods for the decontamination of polluted soils have been proposed and they make use of two different approaches: mobilizing the heavy metals, which allows their removal from soil, or immobilization that maintains the metal concentrations in soils but keeps them in an inert form due to mechanisms like precipitation, complexation or adsorption. Mobilization of the heavy metals is known to cause leaching and increase plant uptake, so this treatment can cause greater problems. Aerogels are incredible nanostructured, lightweight materials with high surface area and tailorable surface chemistry. Their application in environmental cleaning has been increasing in recent years and very promising results have been obtained. The functionalization of the aerogels can give them the ability to interact with heavy metals, retaining the latter via strong adsorptive interactions. Thus, this review surveys the existing literature for remediation of soils using an immobilization approach, i.e. with soil amendments that increase the soil sorption/retention capacity for heavy metals. The considered framework was a set of heavy metals with relevance in polluted Iberian soils, namely Cd, Cr, Cu, Ni, Pb and Zn. Moreover, other adsorbents, especially aerogels, have been used for the removal of these contaminants from aqueous media; because groundwater and soil

  17. Assessing ligand selectivity for uranium over vanadium ions to aid in the discovery of superior adsorbents for extraction of UO 2 2+ from seawater

    DOE PAGES

    Ivanov, Alexander S.; Bryantsev, Vyacheslav S.

    2016-06-06

    Uranium is used as the basic fuel for nuclear power plants, which generate significant amounts of electricity and have life cycle carbon emissions that are as low as renewable energy sources. However, the extraction of this valuable energy commodity from the ground remains controversial, mainly because of environmental and health impacts. Alternatively, seawater offers an enormous uranium resource that may be tapped at minimal environmental cost. Nowadays, amidoxime polymers are the most widely utilized sorbent materials for large-scale extraction of uranium from seawater, but they are not perfectly selective for uranyl, UO 2 2+. In particular, the competition between UOmore » 2 2+ and VO 2+/VO2+ cations poses a significant challenge to the effi-cient mining of UO 2 2+. Thus, screening and rational design of more selective ligands must be accomplished. One of the key components in achieving this goal is the establishment of computational techniques capable of assessing ligand selec-tivity trends. Here, we report an approach based on quantum chemical calculations that achieves high accuracy in repro-ducing experimental aqueous stability constants for VO 2+/VO 2+ complexes with ten different oxygen donor lig-ands. The predictive power of the developed computational protocol was demonstrated for amidoxime-type ligands, providing greater insights into new design strategies for the development of the next generation of adsorbents with high selectivity toward UO 2 2+over VO 2+/VO 2+ ions. Furthermore, the results of calculations suggest that alkylation of amidox-ime moieties present in poly(acrylamidoxime) sorbents can be a potential route to better discrimination between the uranyl and competing vanadium ions within seawater.« less

  18. Optimal Electromagnetic (EM) Geophysical Techniques to Map the Concentration of Subsurface Ice and Adsorbed Water on Mars and the Moon

    NASA Astrophysics Data System (ADS)

    Stillman, D. E.; Grimm, R. E.

    2013-12-01

    dielectric spectroscopy at the Cold Regions Research and Engineering Laboratory (CRREL) permafrost tunnel in Fox, AK. We were able to detect the ice relaxation in the subsurface despite the considerable amount of subsurface unfrozen water due to the presence of montmorillonite clay and much warmer temperatures than Mars or permanently shadowed regions of the Moon. While dielectric spectroscopy can be used to determine ice and adsorbed water content it does not possess the high resolution mapping capability of a GPR. Moreover, GPR cannot detect subsurface ice content in ice-sediment mixtures as evidenced in the interpretation of the Medusae Fossae Formation. Orbital radar surveys show this unit has a low attenuation and a dielectric permittivity near 4. This allows the formation to be interpreted as ice-rich or a dry high-porosity volcanic tuff unit. Therefore, combining GPR and dielectric spectroscopy will enable high-resolution structural and volatile mapping of the subsurface. Furthermore, the addition of neutron spectroscopy would add total hydrogen abundance in the top meter. This could lead to the determination of how much hydrogen resides in ice, adsorbed water, and minerals.

  19. Adsorbent for hydroquinone removal based on graphene oxide functionalized with magnetic cyclodextrin-chitosan.

    PubMed

    Li, Leilei; Fan, Lulu; Sun, Min; Qiu, Huamin; Li, Xiangjun; Duan, Huimin; Luo, Chuannan

    2013-07-01

    Magnetic cyclodextrin-chitosan/graphene oxide (CCGO) with high surface area was synthesized via a simple chemical bonding method. The characteristics results of FTIR, SEM, TEM and XRD showed that CCGO was prepared. The large saturation magnetization (22.35 emu/g) of the synthesized nanoparticles allows fast separation of the CCGO from liquid suspension. These composites could efficiently remove hydroquinone from simulated wastewater with a facile subsequent solid-liquid separation because of their large area, abundant hydroxyl and amino groups with handy operation, and hydrophobicity. The hydroquinone removal process was found to obey the Freundlich adsorption model and its kinetics followed pseudo-second-order rate equation. The hydroquinone removal mechanism of CCGO might be attributed to the electrostatic adsorption of hydroquinone in the form of negatively charged hydroquinone by positively charged chitosan, accompanying hydroquinone absorbed by cavities of the cyclodextrin, and forming hydrogen bonds between hydroquinone and the hydroxyl groups on the surface of CCGO. The used CCGO could be recovered with ethanol. This study provides a promising nanostructured adsorbent with easy separation property for heavy metal ions removal. Copyright © 2013 Elsevier B.V. All rights reserved.

  20. Evaluation of Adsorption Characteristics of a Fibrous Adsorbent Containing Zwitter-Ionic Functional Group, Targeting Organic Acids.

    PubMed

    Nakazawa, Akira; Tang, Ning; Inoue, Yoshinori; Kamichatani, Waka; Katoh, Toshifumi; Saito, Mitsuru; Obara, Kenji; Toriba, Akira; Hayakawa, Kazuichi

    2017-01-01

    Diallylamine-maleic acid copolymer (DAM)-nonwoven fabric (DAM-f), a fibrous adsorbent, contains DAM with zwitter-ionic functional groups and forms a hydration layer on the surface. The aim of this report was to evaluate the adsorption selectivity of DAM-f to semi-volatile organic acid (C1-C5). In the aqueous phase, formic acid dissolved in the hydration layer bound to the imino group of DAM-f due to anion exchange interaction. In the gas phase, the adsorption amounts of organic acids increased with the exposure time. Moreover, the adsorption rate constants correlated with the air/water partition coefficients (log K aw ) for formic acid, propionic acid, butyric acid, valeric acid and isovaleric acid, except for acetic acid. These results indicate that DAM-f is highly selective to hydrophilic compounds which easily move from the air to the hydration layer of DAM-f.